Soil and vegetation recovery following Acacia dealbata clearing in the Tsitsa catchment, Eastern Cape Province of South Africa: implications for ecological restoration
- Authors: Balintulo, Putuma
- Date: 2022-04-06
- Subjects: Acacia South Africa Eastern Cape , Invasive plants South Africa Eastern Cape , Working for Water Programme , Soil restoration South Africa Eastern Cape , Plant nutrients South Africa Eastern Cape , Restoration ecology South Africa Eastern Cape , Clearing of land South Africa Eastern Cape , Legacy effect
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290778 , vital:56783
- Description: Invasion by alien plant species in South Africa continues to compromise the stability of ecosystems by causing declines in biodiversity, altering soil nutrients and processes, and subsequently transforming ecosystem functionality. Control of invasive alien plant species has been widely implemented in South Africa to minimize their negative impacts; however, the legacy effects can persist long after the plant has been removed. The impacts of Acacia dealbata clearing on soil properties and native vegetation recovery remains understudied despite their significance in ecological restoration and monitoring. This comparative study determined the impacts of A. dealbata clearing on both soil physicochemical properties and vegetation in the Eastern Cape Province of South Africa. Soils were collected from three different clearing treatments, namely, cleared, invaded, and uninvaded, on 5 m x 5 m plots over three summer months. The plots were replicated four times for each clearing treatment, making a total of 72 sampling plots. Soils were assessed for soil pH, resistivity, P, C, N, and exchangeable cations as well as soil moisture content, penetration resistance, infiltration rate, hydraulic conductivity, and water repellency. Clearing of A. dealbata did not have any significant effects on most soil nutrients, however, there were variations in soil pH, resistance, and Na. Soil pH was significantly higher in the uninvaded treatments than in the cleared and invaded treatments. Soil moisture content was significantly higher in the cleared treatments than the adjacent invaded and uninvaded treatments, but this was observed in the month of December only. Soil penetration resistance and infiltration rates were significantly higher in the month of December in the cleared treatments. For all clearing treatments, no significant differences were recorded for soil hydraulic conductivity. These results on changes in soil properties following A. dealbata clearing are varied, with some soil properties showing decreases, an indication that removal of A. dealbata has the potential to shift soil properties towards a positive recovery trajectory. This study further assessed whether the clearing of A. dealbata facilitates the recovery of native plant species. Vegetation surveys were conducted in the three above-mentioned treatments and plots. Results showed little recruitment of native grasses and forbs, but the persistence of A. dealbata seedlings in the cleared treatments. Species richness and Shannon-Wiener diversity index were significantly (P < 0.05) higher in the cleared and invaded treatments than the uninvaded treatments, and this was more visible for trees and shrubs. Cover for all species was significantly higher (P < 0.05) in the uninvaded than the cleared and invaded treatments. This study observed the recruitment of some native species in the cleared treatments that were not present in the invaded treatments. Therefore, the recruitment and establishment of some native species, mostly grasses, in the cleared treatments gives assurance that passive restoration is on a positive vegetation recovery trajectory that can lead to recovery of native vegetation after A. dealbata clearing. Therefore, the study concludes that investing in ecological restoration after alien plant clearing is a necessity for complete ecosystem recovery to be achieved. Overall, the study concludes that the removal of A. dealbata triggers changes to some soil properties. Similarly, the study observed recruitment of some native grasses in cleared areas, an indication that alien plant clearing facilitates changes in both soil properties and vegetation. However, soil and vegetation recovery are being hampered by the regrowth of A. dealbata and secondary invaders that were observed in the cleared treatments. Two key recommendations of this study are (i) clearing follow-up to remove recruiting seedlings of invasive plant species and secondary invaders should be timeous and well-funded, and (ii) active restoration should be considered to speed-up soil and vegetation recovery processes. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Balintulo, Putuma
- Date: 2022-04-06
- Subjects: Acacia South Africa Eastern Cape , Invasive plants South Africa Eastern Cape , Working for Water Programme , Soil restoration South Africa Eastern Cape , Plant nutrients South Africa Eastern Cape , Restoration ecology South Africa Eastern Cape , Clearing of land South Africa Eastern Cape , Legacy effect
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290778 , vital:56783
- Description: Invasion by alien plant species in South Africa continues to compromise the stability of ecosystems by causing declines in biodiversity, altering soil nutrients and processes, and subsequently transforming ecosystem functionality. Control of invasive alien plant species has been widely implemented in South Africa to minimize their negative impacts; however, the legacy effects can persist long after the plant has been removed. The impacts of Acacia dealbata clearing on soil properties and native vegetation recovery remains understudied despite their significance in ecological restoration and monitoring. This comparative study determined the impacts of A. dealbata clearing on both soil physicochemical properties and vegetation in the Eastern Cape Province of South Africa. Soils were collected from three different clearing treatments, namely, cleared, invaded, and uninvaded, on 5 m x 5 m plots over three summer months. The plots were replicated four times for each clearing treatment, making a total of 72 sampling plots. Soils were assessed for soil pH, resistivity, P, C, N, and exchangeable cations as well as soil moisture content, penetration resistance, infiltration rate, hydraulic conductivity, and water repellency. Clearing of A. dealbata did not have any significant effects on most soil nutrients, however, there were variations in soil pH, resistance, and Na. Soil pH was significantly higher in the uninvaded treatments than in the cleared and invaded treatments. Soil moisture content was significantly higher in the cleared treatments than the adjacent invaded and uninvaded treatments, but this was observed in the month of December only. Soil penetration resistance and infiltration rates were significantly higher in the month of December in the cleared treatments. For all clearing treatments, no significant differences were recorded for soil hydraulic conductivity. These results on changes in soil properties following A. dealbata clearing are varied, with some soil properties showing decreases, an indication that removal of A. dealbata has the potential to shift soil properties towards a positive recovery trajectory. This study further assessed whether the clearing of A. dealbata facilitates the recovery of native plant species. Vegetation surveys were conducted in the three above-mentioned treatments and plots. Results showed little recruitment of native grasses and forbs, but the persistence of A. dealbata seedlings in the cleared treatments. Species richness and Shannon-Wiener diversity index were significantly (P < 0.05) higher in the cleared and invaded treatments than the uninvaded treatments, and this was more visible for trees and shrubs. Cover for all species was significantly higher (P < 0.05) in the uninvaded than the cleared and invaded treatments. This study observed the recruitment of some native species in the cleared treatments that were not present in the invaded treatments. Therefore, the recruitment and establishment of some native species, mostly grasses, in the cleared treatments gives assurance that passive restoration is on a positive vegetation recovery trajectory that can lead to recovery of native vegetation after A. dealbata clearing. Therefore, the study concludes that investing in ecological restoration after alien plant clearing is a necessity for complete ecosystem recovery to be achieved. Overall, the study concludes that the removal of A. dealbata triggers changes to some soil properties. Similarly, the study observed recruitment of some native grasses in cleared areas, an indication that alien plant clearing facilitates changes in both soil properties and vegetation. However, soil and vegetation recovery are being hampered by the regrowth of A. dealbata and secondary invaders that were observed in the cleared treatments. Two key recommendations of this study are (i) clearing follow-up to remove recruiting seedlings of invasive plant species and secondary invaders should be timeous and well-funded, and (ii) active restoration should be considered to speed-up soil and vegetation recovery processes. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2022
- Full Text:
- Date Issued: 2022-04-06
The impact of urban gardening on household food security: evidence from Makhanda East, Eastern Cape Province, South Africa
- Bruwer, Guillaume Marcel Xavier
- Authors: Bruwer, Guillaume Marcel Xavier
- Date: 2022-04-06
- Subjects: Food security South Africa Makhanda , Urban agriculture South Africa Makhanda , Urban gardening South Africa Makhanda , Sustainable development South Africa Makhanda , South Africa Economic conditions , Subsistence farming South Africa Makhanda , Economic impact analysis South Africa Makhanda , Propensity Score Matching (PSM)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/263575 , vital:53640
- Description: Urban gardening in townships is a common coping strategy employed by poor inhabitants to improve food security, earn income through sales, and generate cost-savings through home consumption of fresh produce. Food security is a cornerstone of human development and welfare, and the achievement thereof remains a global challenge. The majority of academic research and policy documentation traditionally positions food insecurity as a rural phenomenon. However, recent trends point to an increase in food insecurity in urban areas, particularly in low-income areas such as townships. In South Africa, rapid urbanization has led to burgeoning townships and rapidly expanding low-income informal settlements characterised by poverty, unemployment, and food insecurity. Research concerned with the role that urban agricultural production plays in contributing to the food security of poor households is scarce and not well understood. This research, therefore, aimed to contribute to the limited research which specifically examines urban food security, and the role urban agriculture play in the achievement of household food security. The study employed collective action theory and utility theory to firstly provides an in-depth examination of the determinants of participation in urban gardening using Probit regression modeling. The second research objective was to perform an impact evaluation of participation in urban gardening on selected household food security indicators including Household Dietary Diversity Scores (HDDS), the Household Hunger Scale (HHS) and the Coping Strategy Index (CSI) using Propensity Score Matching (PSM). Purposive and snowball sampling methods were employed to obtain a sample of 60 urban gardeners and a control group of 55 non-gardening households from Extension 6, 7 and 10 townships as well as Joza Location in Makhanda East, Eastern Cape Province. Households were surveyed using a structured household food security questionnaire. A focus group discussion was held with the Linomtha Community Garden members and key informant interviews were undertaken with important stakeholders such as the local extension officers. Descriptive analysis revealed that urban gardening households (UGs) had older household heads who were less educated, and that land and water availability were the dominant constraints to increases in agricultural production. Results from the probit and average marginal effects models showed that the likelihood of participation significantly increased when household unemployment and dependency increased and that households who were engaged in off-farm economic activity were more likely to participate in urban gardening. The impact evaluation was performed using PSM and Average Treatment Effect on the Treated (ATT). Analysis illustrated that participation in urban gardening does significantly reduce both the full CSI and Reduced CSI. Thus, participation in urban gardening improves the food security of participating households by significantly reducing the frequency of participating households (UGs) applying undesirable coping strategies such as sending children elsewhere other than the household, borrowing food from other households and reducing the number of meals eaten in a day due to food shortages. This study posits that urban gardening alone will not eradicate the rampant food insecurity and poverty which pervades in South Africa’s townships. However, urban gardening participation does contribute to the construction of a sustainable, urban livelihood by reducing the number and severity of the undesirable coping strategies that food insecure households employ by providing some nutritious produce as well improved social capital through gardening networks and supporting institutions. It is recommended that policy makers, at a national and municipal level, need to create a clearer directive for the integration of urban food production into the urban food marketplace thus increasing access to income generating channels for small-scale home, and community gardeners. Co-operation between private and public institutions for food security and urban gardeners needs to be fostered and awareness of opportunities to participate in urban gardens needs to be improved. Central to the developmental challenges that rapid increases in urbanization and food insecurity in poor urban areas, is the need for national and local governments to improve access to economic opportunities in township areas - both in urban agriculture and in other, skills intensive sectors. , Thesis (MEcon) -- Faculty of Commerce, Economics and Economic History, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Bruwer, Guillaume Marcel Xavier
- Date: 2022-04-06
- Subjects: Food security South Africa Makhanda , Urban agriculture South Africa Makhanda , Urban gardening South Africa Makhanda , Sustainable development South Africa Makhanda , South Africa Economic conditions , Subsistence farming South Africa Makhanda , Economic impact analysis South Africa Makhanda , Propensity Score Matching (PSM)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/263575 , vital:53640
- Description: Urban gardening in townships is a common coping strategy employed by poor inhabitants to improve food security, earn income through sales, and generate cost-savings through home consumption of fresh produce. Food security is a cornerstone of human development and welfare, and the achievement thereof remains a global challenge. The majority of academic research and policy documentation traditionally positions food insecurity as a rural phenomenon. However, recent trends point to an increase in food insecurity in urban areas, particularly in low-income areas such as townships. In South Africa, rapid urbanization has led to burgeoning townships and rapidly expanding low-income informal settlements characterised by poverty, unemployment, and food insecurity. Research concerned with the role that urban agricultural production plays in contributing to the food security of poor households is scarce and not well understood. This research, therefore, aimed to contribute to the limited research which specifically examines urban food security, and the role urban agriculture play in the achievement of household food security. The study employed collective action theory and utility theory to firstly provides an in-depth examination of the determinants of participation in urban gardening using Probit regression modeling. The second research objective was to perform an impact evaluation of participation in urban gardening on selected household food security indicators including Household Dietary Diversity Scores (HDDS), the Household Hunger Scale (HHS) and the Coping Strategy Index (CSI) using Propensity Score Matching (PSM). Purposive and snowball sampling methods were employed to obtain a sample of 60 urban gardeners and a control group of 55 non-gardening households from Extension 6, 7 and 10 townships as well as Joza Location in Makhanda East, Eastern Cape Province. Households were surveyed using a structured household food security questionnaire. A focus group discussion was held with the Linomtha Community Garden members and key informant interviews were undertaken with important stakeholders such as the local extension officers. Descriptive analysis revealed that urban gardening households (UGs) had older household heads who were less educated, and that land and water availability were the dominant constraints to increases in agricultural production. Results from the probit and average marginal effects models showed that the likelihood of participation significantly increased when household unemployment and dependency increased and that households who were engaged in off-farm economic activity were more likely to participate in urban gardening. The impact evaluation was performed using PSM and Average Treatment Effect on the Treated (ATT). Analysis illustrated that participation in urban gardening does significantly reduce both the full CSI and Reduced CSI. Thus, participation in urban gardening improves the food security of participating households by significantly reducing the frequency of participating households (UGs) applying undesirable coping strategies such as sending children elsewhere other than the household, borrowing food from other households and reducing the number of meals eaten in a day due to food shortages. This study posits that urban gardening alone will not eradicate the rampant food insecurity and poverty which pervades in South Africa’s townships. However, urban gardening participation does contribute to the construction of a sustainable, urban livelihood by reducing the number and severity of the undesirable coping strategies that food insecure households employ by providing some nutritious produce as well improved social capital through gardening networks and supporting institutions. It is recommended that policy makers, at a national and municipal level, need to create a clearer directive for the integration of urban food production into the urban food marketplace thus increasing access to income generating channels for small-scale home, and community gardeners. Co-operation between private and public institutions for food security and urban gardeners needs to be fostered and awareness of opportunities to participate in urban gardens needs to be improved. Central to the developmental challenges that rapid increases in urbanization and food insecurity in poor urban areas, is the need for national and local governments to improve access to economic opportunities in township areas - both in urban agriculture and in other, skills intensive sectors. , Thesis (MEcon) -- Faculty of Commerce, Economics and Economic History, 2022
- Full Text:
- Date Issued: 2022-04-06
The effectiveness of networking and collaboration in creative hubs: a case of Hub@Goethe
- Authors: De Beer, Magdalena Gertruda
- Date: 2022-04-06
- Subjects: Cultural industries South Africa , Cultural industries Economic aspects South Africa , Economic development projects South Africa , Social entrepreneurship South Africa , Creative ability Economic aspects South Africa , Social capital (Sociology) South Africa , Social networks South Africa , Hub@Goethe
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284504 , vital:56069
- Description: This research took the form of a case study investigating the effectiveness of a single hub in South Africa, namely Hub@Goethe in Johannesburg. The context of the creative economy and creative industries provided insight into the experiences of creative cultural labourers in the new economic model. The context emphasised the research problem which considered the difficulties experienced by creative and cultural entrepreneurs and their career paths who, through labour precarity, remain isolated from the market, without access to physical spaces, network connections and business knowledge to realise their business ideas. The literature reviewed revealed how co-working office spaces, creative spaces and hubs provide creative entrepreneurs with the spatial infrastructure, amenities, and network access to mitigate challenges in the creative cultural sectors. These spaces offer a multitude of different amenities which is specific to their community’s needs. Guided by the theory of social capital and structural holes reviewed in the literature, the effectiveness was assessed by the hub’s ability to provide network access benefits or resource endowments. The research looked at whether the hub could provide creative cultural entrepreneurs with resource benefits such as a) access to social interactions, collaboration, and knowledge sharing, b) access to business or professional skills-based education programmes and mentorship, c) access to market and d) generation both social and economic benefit. The research adopted a qualitative approach, seeking insights into the creative entrepreneurs’ experiences at the hub utilising one-to-one interviews. The thematic analysis confirmed that the hub was effective overall in providing entrepreneurs with access to benefits or resource endowments embedded in the network, confirming that hubs may be an effective tool in mitigating difficulties experienced by creative entrepreneurs in the creative industries. The research also showed areas of improvement where the hub could increase its experienced effectiveness, especially in reference to routes to market. The research findings inferred the importance of physical space, proximity and accessibility has on collaborative practices amongst creative entrepreneurs within the hub space. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: De Beer, Magdalena Gertruda
- Date: 2022-04-06
- Subjects: Cultural industries South Africa , Cultural industries Economic aspects South Africa , Economic development projects South Africa , Social entrepreneurship South Africa , Creative ability Economic aspects South Africa , Social capital (Sociology) South Africa , Social networks South Africa , Hub@Goethe
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284504 , vital:56069
- Description: This research took the form of a case study investigating the effectiveness of a single hub in South Africa, namely Hub@Goethe in Johannesburg. The context of the creative economy and creative industries provided insight into the experiences of creative cultural labourers in the new economic model. The context emphasised the research problem which considered the difficulties experienced by creative and cultural entrepreneurs and their career paths who, through labour precarity, remain isolated from the market, without access to physical spaces, network connections and business knowledge to realise their business ideas. The literature reviewed revealed how co-working office spaces, creative spaces and hubs provide creative entrepreneurs with the spatial infrastructure, amenities, and network access to mitigate challenges in the creative cultural sectors. These spaces offer a multitude of different amenities which is specific to their community’s needs. Guided by the theory of social capital and structural holes reviewed in the literature, the effectiveness was assessed by the hub’s ability to provide network access benefits or resource endowments. The research looked at whether the hub could provide creative cultural entrepreneurs with resource benefits such as a) access to social interactions, collaboration, and knowledge sharing, b) access to business or professional skills-based education programmes and mentorship, c) access to market and d) generation both social and economic benefit. The research adopted a qualitative approach, seeking insights into the creative entrepreneurs’ experiences at the hub utilising one-to-one interviews. The thematic analysis confirmed that the hub was effective overall in providing entrepreneurs with access to benefits or resource endowments embedded in the network, confirming that hubs may be an effective tool in mitigating difficulties experienced by creative entrepreneurs in the creative industries. The research also showed areas of improvement where the hub could increase its experienced effectiveness, especially in reference to routes to market. The research findings inferred the importance of physical space, proximity and accessibility has on collaborative practices amongst creative entrepreneurs within the hub space. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-04-06
Comparison of a novel HPLC method and conventional protein assays for the quantitation of insulin aspart in Novorapid®
- Authors: Dickson, Courtney Rae
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/290704 , vital:56776
- Description: Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Dickson, Courtney Rae
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/290704 , vital:56776
- Description: Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2022
- Full Text:
- Date Issued: 2022-04-06
The host specificity and efficacy of Phenrica guerini (Bechyné) (Coleoptera: Chrysomelidae), a candidate biological control agent of Pereskia aculeata Miller (Cactaceae) in Australia
- Authors: Dixon, Elizabeth Anne
- Date: 2022-04-06
- Subjects: Chrysomelidae Australia , Pereskia Australia , Pereskia Biological control Australia , Invasive plants Biological control Australia , Insects as biological pest control agents Australia , Cactus Biological control Australia
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290826 , vital:56789
- Description: Pereskia aculeata Miller (Cactaceae) is a primitive creeping cactus that originated from South America and has become an invasive alien plant in South Africa and Australia. Due to its vine-like growth form mechanical and chemical control are not feasible options for its control, therefore biological control is the best option for controlling this plant. Phenrica guerini (Bechyné) (Chrysomelidae) is a leaf-feeding flea beetle that has been released as a biological control agent against Pe. aculeata in South Africa and has been shown to be damaging at some sites in the country. In this thesis, further studies into the use of Ph. guerini as a biological control agent against Pe. aculeata were conducted to determine whether the beetle should be released as an agent against the target weed in Australia. The host range of a potential biological control agent is important to determine as only monophagous agents, or agents with suitably restricted host ranges, should be considered for release. Host specificity testing was conducted to determine if Ph. guerini was suitably specific for release in Australia. Phenrica guerini larvae only fed and partially developed on three out of 25 test plants, but failed to pupate on any plants besides Pe. aculeata. Adult beetles did not feed on any test plants and only oviposited on one test plant species. Phenrica guerini did not develop on any plant other than the target weed and is therefore suitably host specific for release in Australia. The efficacy of a potential agent is also important to consider as the release of an ineffective agent can reduce the success of a biological control programme. A laboratory based pre-release efficacy assessment was done to determine the impact that Ph. guerini could have on Pe. aculeata. There was a significant difference between the control plants and those with larvae, with an average of 72 (S.E. ± 12.33) less leaves on plants with feeding and the main stem of the plant being 11.1 cm (S.E. ± 7.17) shorter. Although there were no significant differences observed in the number of additional stems, and weights of the different plant parts, this was not a long term study and many of these differences would not have been observed in a short period. Based on the impact observed on the leaves and the main stem, and various field studies that have been done to assess the impact of Ph. guerini on Pe. aculeata in the field in South Africa, Ph. guerini appears to be a potentially damaging agent. As Pe. aculeata is still in its early stages of invasion in Australia the beetle has the potential to be damaging and reduce the invasion trajectory of the plant. This study showed that the beetle is suitably host specific and potentially damaging enough to be recommended for release as a biological control agent against Pe. aculeata in Australia. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Dixon, Elizabeth Anne
- Date: 2022-04-06
- Subjects: Chrysomelidae Australia , Pereskia Australia , Pereskia Biological control Australia , Invasive plants Biological control Australia , Insects as biological pest control agents Australia , Cactus Biological control Australia
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290826 , vital:56789
- Description: Pereskia aculeata Miller (Cactaceae) is a primitive creeping cactus that originated from South America and has become an invasive alien plant in South Africa and Australia. Due to its vine-like growth form mechanical and chemical control are not feasible options for its control, therefore biological control is the best option for controlling this plant. Phenrica guerini (Bechyné) (Chrysomelidae) is a leaf-feeding flea beetle that has been released as a biological control agent against Pe. aculeata in South Africa and has been shown to be damaging at some sites in the country. In this thesis, further studies into the use of Ph. guerini as a biological control agent against Pe. aculeata were conducted to determine whether the beetle should be released as an agent against the target weed in Australia. The host range of a potential biological control agent is important to determine as only monophagous agents, or agents with suitably restricted host ranges, should be considered for release. Host specificity testing was conducted to determine if Ph. guerini was suitably specific for release in Australia. Phenrica guerini larvae only fed and partially developed on three out of 25 test plants, but failed to pupate on any plants besides Pe. aculeata. Adult beetles did not feed on any test plants and only oviposited on one test plant species. Phenrica guerini did not develop on any plant other than the target weed and is therefore suitably host specific for release in Australia. The efficacy of a potential agent is also important to consider as the release of an ineffective agent can reduce the success of a biological control programme. A laboratory based pre-release efficacy assessment was done to determine the impact that Ph. guerini could have on Pe. aculeata. There was a significant difference between the control plants and those with larvae, with an average of 72 (S.E. ± 12.33) less leaves on plants with feeding and the main stem of the plant being 11.1 cm (S.E. ± 7.17) shorter. Although there were no significant differences observed in the number of additional stems, and weights of the different plant parts, this was not a long term study and many of these differences would not have been observed in a short period. Based on the impact observed on the leaves and the main stem, and various field studies that have been done to assess the impact of Ph. guerini on Pe. aculeata in the field in South Africa, Ph. guerini appears to be a potentially damaging agent. As Pe. aculeata is still in its early stages of invasion in Australia the beetle has the potential to be damaging and reduce the invasion trajectory of the plant. This study showed that the beetle is suitably host specific and potentially damaging enough to be recommended for release as a biological control agent against Pe. aculeata in Australia. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2022
- Full Text:
- Date Issued: 2022-04-06
The challenges and opportunities in ESG integration in investment activities for private equity firms/funds in South Africa
- Authors: Dube, Cuma Velile
- Date: 2022-04-06
- Subjects: Social responsibility of business South Africa , Investments Moral and ethical aspects South Africa , Private equity South Africa , Investments Environmental aspects South Africa , Investments Social aspects South Africa , Investments Law and legislation South Africa , United Nations Principles of Responsible Investing (UNPRI)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284493 , vital:56068
- Description: Responsible Investing (RI) is an investment strategy that considers not only the economic but also the environmental, social and governance (ESG) issues in the investment analysis and post-investment activities. The consideration of ESG issues is aimed at generating long-term risk-adjusted financial returns and a positive social and environmental impact. This research seeks to contribute to the study of responsible investment (RI), as it relates to private equity investments, an area not well researched. This research also seeks to contribute to the academic literature on responsible institutional investment in South Africa; the opportunities it presents to optimise portfolios, as well as the means with which the challenges faced in integrating ESG factors in investment activities may be overcome. More specifically, the challenges and opportunities for the integration of ESG factors in the investment process were investigated through the experiences of a small sample of South African private equity firms. The sample of private equity firms that participated in this research are signatories of the United Nations Principles of Responsible Investing (UNPRI). Representatives of the participating firms were interviewed in line with the qualitative research design and the post-positivist paradigm of this research. The research design and paradigm are chosen to explore the experiences of practitioners in their integration of ESG issues in the investment process. This research shows that the challenges to ESG integration for the private equity firms considered have remained largely consistent over the last ten years. The challenges include industry skills and knowledge gap and the lack of reliable and comparable ESG data at the portfolio company level. The Opportunities presented, by adopting responsible investing as an investment strategy, are rooted in protecting the downside (risk management) and in finding new value creation opportunities. In summary, it was found that the participating firms continue to face significant capacity challenges in overcoming the challenges to mainstreaming ESG in investment processes. Further research may explore whether the challenges and opportunities that persist from the findings of this research are pervasive throughout the entire sector and whether innovative ways have been found to overcome the challenges have been found by private equity firms that are not signatories of the UNPRI. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Dube, Cuma Velile
- Date: 2022-04-06
- Subjects: Social responsibility of business South Africa , Investments Moral and ethical aspects South Africa , Private equity South Africa , Investments Environmental aspects South Africa , Investments Social aspects South Africa , Investments Law and legislation South Africa , United Nations Principles of Responsible Investing (UNPRI)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284493 , vital:56068
- Description: Responsible Investing (RI) is an investment strategy that considers not only the economic but also the environmental, social and governance (ESG) issues in the investment analysis and post-investment activities. The consideration of ESG issues is aimed at generating long-term risk-adjusted financial returns and a positive social and environmental impact. This research seeks to contribute to the study of responsible investment (RI), as it relates to private equity investments, an area not well researched. This research also seeks to contribute to the academic literature on responsible institutional investment in South Africa; the opportunities it presents to optimise portfolios, as well as the means with which the challenges faced in integrating ESG factors in investment activities may be overcome. More specifically, the challenges and opportunities for the integration of ESG factors in the investment process were investigated through the experiences of a small sample of South African private equity firms. The sample of private equity firms that participated in this research are signatories of the United Nations Principles of Responsible Investing (UNPRI). Representatives of the participating firms were interviewed in line with the qualitative research design and the post-positivist paradigm of this research. The research design and paradigm are chosen to explore the experiences of practitioners in their integration of ESG issues in the investment process. This research shows that the challenges to ESG integration for the private equity firms considered have remained largely consistent over the last ten years. The challenges include industry skills and knowledge gap and the lack of reliable and comparable ESG data at the portfolio company level. The Opportunities presented, by adopting responsible investing as an investment strategy, are rooted in protecting the downside (risk management) and in finding new value creation opportunities. In summary, it was found that the participating firms continue to face significant capacity challenges in overcoming the challenges to mainstreaming ESG in investment processes. Further research may explore whether the challenges and opportunities that persist from the findings of this research are pervasive throughout the entire sector and whether innovative ways have been found to overcome the challenges have been found by private equity firms that are not signatories of the UNPRI. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-04-06
Integrating blockchain and microgrid technology to enable peer-to-peer energy trading: a business process model
- Authors: Higgs, James
- Date: 2022-04-06
- Subjects: Blockchains (Databases) , Peer-to-peer architecture (Computer networks) , Electric power-plants Decentralization South Africa , Microgrids (Smart power grids) South Africa , Energy trading , Business process model
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284559 , vital:56074
- Description: Traditional centralised energy systems are coming under increasing pressure because of decarbonisation, decentralisation, and digitisation. A lack of energy security and the inability to manage bi-directional electricity flows constitute two of the biggest challenges faced by centralised systems. Furthermore, in South Africa, the country’s energy system remains monopolised with one large utility satisfying most of the country’s electricity demand. This study is motivated by the need to address energy security within such a monopolised market. To redress the problems highlighted above, this study explores how blockchain and microgrid technology can be integrated to enable decentralised energy production and trading in South Africa. As such, this study develops a fully integrated blockchain-based microgrid energy trading system model. The functional requirements of the system are presented in the form of a business process model. Amongst other benefits, an active blockchain-based microgrid energy trading system provides a means to bolster energy security for the systems’ users. A unique aspect of this study’s approach to energy trading is the utilisation of blockchain’s native tokenizing capabilities. Prosumer energy tokens are minted to create a digital currency for local peer-to-peer energy exchange. A commons-rule based approach is adopted for governing energy resources. As such, this study demonstrates that commons-based solutions provide a feasible alternative to market and profit driven trading for organizing local energy exchange. The primary deliverable of this study satisfies the request of various blockchain researchers for blockchain research to focus on holistic conceptualisations, rather than on the minutiae of blockchain technicalities. Eight core functional requirements of a blockchain energy trading system were identified prior to the construction of the process model. The functional requirements were elicited during a scoping review as a part of the secondary data collection process. Expert review was utilised to verify the functional requirements of the blockchain energy trading system. Once the experts were identified, each expert completed a questionnaire with the intention to verify the requirements. The above process constituted the expert review process for the study. Additionally, the syntactic correctness of the business process model was verified by a business process modelling expert. Weber’s Theory of Evaluation constitutes the theoretical underpinning for the evaluation of the system parts. This study contributes the first publicly accessible business process models of a blockchain-based microgrid energy trading system. This study seeks to advance the discussion of a more integrative and cross disciplinary approach concerning blockchain research, particularly as it pertains to microgrid energy trading. , Thesis (MCom) -- Faculty of Commerce, Department of Information Systems, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Higgs, James
- Date: 2022-04-06
- Subjects: Blockchains (Databases) , Peer-to-peer architecture (Computer networks) , Electric power-plants Decentralization South Africa , Microgrids (Smart power grids) South Africa , Energy trading , Business process model
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284559 , vital:56074
- Description: Traditional centralised energy systems are coming under increasing pressure because of decarbonisation, decentralisation, and digitisation. A lack of energy security and the inability to manage bi-directional electricity flows constitute two of the biggest challenges faced by centralised systems. Furthermore, in South Africa, the country’s energy system remains monopolised with one large utility satisfying most of the country’s electricity demand. This study is motivated by the need to address energy security within such a monopolised market. To redress the problems highlighted above, this study explores how blockchain and microgrid technology can be integrated to enable decentralised energy production and trading in South Africa. As such, this study develops a fully integrated blockchain-based microgrid energy trading system model. The functional requirements of the system are presented in the form of a business process model. Amongst other benefits, an active blockchain-based microgrid energy trading system provides a means to bolster energy security for the systems’ users. A unique aspect of this study’s approach to energy trading is the utilisation of blockchain’s native tokenizing capabilities. Prosumer energy tokens are minted to create a digital currency for local peer-to-peer energy exchange. A commons-rule based approach is adopted for governing energy resources. As such, this study demonstrates that commons-based solutions provide a feasible alternative to market and profit driven trading for organizing local energy exchange. The primary deliverable of this study satisfies the request of various blockchain researchers for blockchain research to focus on holistic conceptualisations, rather than on the minutiae of blockchain technicalities. Eight core functional requirements of a blockchain energy trading system were identified prior to the construction of the process model. The functional requirements were elicited during a scoping review as a part of the secondary data collection process. Expert review was utilised to verify the functional requirements of the blockchain energy trading system. Once the experts were identified, each expert completed a questionnaire with the intention to verify the requirements. The above process constituted the expert review process for the study. Additionally, the syntactic correctness of the business process model was verified by a business process modelling expert. Weber’s Theory of Evaluation constitutes the theoretical underpinning for the evaluation of the system parts. This study contributes the first publicly accessible business process models of a blockchain-based microgrid energy trading system. This study seeks to advance the discussion of a more integrative and cross disciplinary approach concerning blockchain research, particularly as it pertains to microgrid energy trading. , Thesis (MCom) -- Faculty of Commerce, Department of Information Systems, 2022
- Full Text:
- Date Issued: 2022-04-06
The elucidation of nickel and zinc based Metal Organic Frameworks (MOFs) using a polycarboxylate-benzene ligand: a synthetic, spectroscopic, and thermoanalytical study
- Authors: Hodgson, Ivan Mark
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/290877 , vital:56795
- Description: Thesis (MSc) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Hodgson, Ivan Mark
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/290877 , vital:56795
- Description: Thesis (MSc) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-04-06
Bioethical analysis of COVID19, WASH/waste and related disaster management implications
- Authors: Iheanetu, Chidinma Uchenna
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232250 , vital:49975
- Description: Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Iheanetu, Chidinma Uchenna
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232250 , vital:49975
- Description: Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2022
- Full Text:
- Date Issued: 2022-04-06
Potential running related injury contributors in South African long-distance runners
- Authors: Jäger, Chloë Rose Laubscher
- Date: 2022-04-06
- Subjects: Running injuries South Africa , Long-distance running South Africa , Running Physiological aspects , Running shoes , Biomechanics , Chi-square test , Fisher exact test
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290943 , vital:56801
- Description: Running related injuries (RRIs) are a common problem among long-distance runners, with injury rates ranging from 19.4% to 79.3%. Many studies have been done, investigating possible contributors to RRIs however, very few studies have investigated RRIs in South African long-distance runners, a population which may differ from previously studied populations. The current study aimed to build a descriptive profile of South African long-distance runners, as well as to determine associated factors that may contribute to RRIs. In order to do this, a cross-sectional, retrospective study design was employed using a questionnaire which was mostly electronically distributed. The sample consisted of 378 long-distance runners from each province in South Africa (SA). Using the Chi-square analysis and Fisher exact tests, significant associations were established (p<0.05). The current study found that certain RRI variables were associated with specific aspects of the participants’ personal characteristics and demographics, training characteristics, running experience, footwear, and cross training activities. Footwear and training characteristics produced the largest number of significant RRI associations. The findings of the current study could assist future research on RRIs in South African long-distance runners, by informing researchers of potential areas where more in-depth research is needed. In the long term, researchers may be able to narrow down the main contributors to RRI, possibly decreasing RRI rates in the unique population of South African long-distance runners. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Jäger, Chloë Rose Laubscher
- Date: 2022-04-06
- Subjects: Running injuries South Africa , Long-distance running South Africa , Running Physiological aspects , Running shoes , Biomechanics , Chi-square test , Fisher exact test
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290943 , vital:56801
- Description: Running related injuries (RRIs) are a common problem among long-distance runners, with injury rates ranging from 19.4% to 79.3%. Many studies have been done, investigating possible contributors to RRIs however, very few studies have investigated RRIs in South African long-distance runners, a population which may differ from previously studied populations. The current study aimed to build a descriptive profile of South African long-distance runners, as well as to determine associated factors that may contribute to RRIs. In order to do this, a cross-sectional, retrospective study design was employed using a questionnaire which was mostly electronically distributed. The sample consisted of 378 long-distance runners from each province in South Africa (SA). Using the Chi-square analysis and Fisher exact tests, significant associations were established (p<0.05). The current study found that certain RRI variables were associated with specific aspects of the participants’ personal characteristics and demographics, training characteristics, running experience, footwear, and cross training activities. Footwear and training characteristics produced the largest number of significant RRI associations. The findings of the current study could assist future research on RRIs in South African long-distance runners, by informing researchers of potential areas where more in-depth research is needed. In the long term, researchers may be able to narrow down the main contributors to RRI, possibly decreasing RRI rates in the unique population of South African long-distance runners. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2022
- Full Text:
- Date Issued: 2022-04-06
Exploring the entrepreneurial intention of students in one Higher Education Institution (HEI)
- Authors: Kenye-Duma, Ayanda Rachel
- Date: 2022-04-06
- Subjects: Entrepreneurship South Africa , Intention , Entrepreneurship Study and teaching (Higher) South Africa , Students Attitudes , Social entrepreneurship , Social capital (Sociology) , Unemployment South Africa , Entrepreneurship Development in Higher Education (EDHE)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284514 , vital:56070
- Description: This study was interpretive and qualitatively explored students' entrepreneurial intentions at Rhodes University. It was conducted to understand entrepreneurship among students. Understanding students' entrepreneurship is critical as entrepreneurship is touted as a reasonable response to alleviate the high unemployment in South Africa. The study explored how students became entrepreneurs (or how their entrepreneurship intentions were formed) and the factors that enhanced (enablers and barriers) and inhibited them. The significance of living with and after COVID-19, youth and graduate unemployment alleviation places entrepreneurship development by institutions of higher learning, governments and private sector in the centre of economic recovery. The establishment of the Entrepreneurship Development in Higher Education (EDHE) in 2016, highlights the commitment of the South African government, for Higher Education Institutions (HEI) to engage more in entrepreneurship and do more research to understand how students become entrepreneurs and unravel the challenges. Understanding students' entrepreneurship intentions can facilitate a supportive environment for students entrepreneurship. With “very little research about student entrepreneurship at this university” being the guiding research problem, the aim was to gain insight into the entrepreneurship intention of university students by exploring factors that influence students to become entrepreneurs. The study employed Ajzen’s Theory of Planned Behaviour to explore the entrepreneurial intentions of university students in terms of the underlying attitudes, subjective norms, and perceived behavioural control. The students who participated in the study fell into three categories of entrepreneurial intention: (i) Intending to start a business, (ii) starting a business, and (ii) those who were already operating a business. All the participants, irrespective of their stage of entrepreneurial intention, demonstrated a positive attitude and self-efficacy. All participants showed self-efficacy by identifying barriers and taking positive steps to overcome them. The main barriers were access to funding, capital, training, business opportunities with the university and lack of interaction with established entrepreneurs. The results demonstrated the close interplay of attitudes, social norms and perceived behavioural control in students’ entrepreneurial intentions. Social recognition of entrepreneurship, social capital, education and role models contributed to positive attitudes, and social norms influenced students’ entrepreneurial intentions. A supportive environment was found to be critical for nurturing entrepreneurship intentions. The study recommends a supportive climate cultivated by Rhodes University to promote entrepreneurship. The supportive environment must include the elevation of entrepreneurship in prominent offices of the university, strengthening entrepreneurship societies and interactions with established entrepreneurs, and engagement with the private sector to contribute and promote entrepreneurship among students. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Kenye-Duma, Ayanda Rachel
- Date: 2022-04-06
- Subjects: Entrepreneurship South Africa , Intention , Entrepreneurship Study and teaching (Higher) South Africa , Students Attitudes , Social entrepreneurship , Social capital (Sociology) , Unemployment South Africa , Entrepreneurship Development in Higher Education (EDHE)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284514 , vital:56070
- Description: This study was interpretive and qualitatively explored students' entrepreneurial intentions at Rhodes University. It was conducted to understand entrepreneurship among students. Understanding students' entrepreneurship is critical as entrepreneurship is touted as a reasonable response to alleviate the high unemployment in South Africa. The study explored how students became entrepreneurs (or how their entrepreneurship intentions were formed) and the factors that enhanced (enablers and barriers) and inhibited them. The significance of living with and after COVID-19, youth and graduate unemployment alleviation places entrepreneurship development by institutions of higher learning, governments and private sector in the centre of economic recovery. The establishment of the Entrepreneurship Development in Higher Education (EDHE) in 2016, highlights the commitment of the South African government, for Higher Education Institutions (HEI) to engage more in entrepreneurship and do more research to understand how students become entrepreneurs and unravel the challenges. Understanding students' entrepreneurship intentions can facilitate a supportive environment for students entrepreneurship. With “very little research about student entrepreneurship at this university” being the guiding research problem, the aim was to gain insight into the entrepreneurship intention of university students by exploring factors that influence students to become entrepreneurs. The study employed Ajzen’s Theory of Planned Behaviour to explore the entrepreneurial intentions of university students in terms of the underlying attitudes, subjective norms, and perceived behavioural control. The students who participated in the study fell into three categories of entrepreneurial intention: (i) Intending to start a business, (ii) starting a business, and (ii) those who were already operating a business. All the participants, irrespective of their stage of entrepreneurial intention, demonstrated a positive attitude and self-efficacy. All participants showed self-efficacy by identifying barriers and taking positive steps to overcome them. The main barriers were access to funding, capital, training, business opportunities with the university and lack of interaction with established entrepreneurs. The results demonstrated the close interplay of attitudes, social norms and perceived behavioural control in students’ entrepreneurial intentions. Social recognition of entrepreneurship, social capital, education and role models contributed to positive attitudes, and social norms influenced students’ entrepreneurial intentions. A supportive environment was found to be critical for nurturing entrepreneurship intentions. The study recommends a supportive climate cultivated by Rhodes University to promote entrepreneurship. The supportive environment must include the elevation of entrepreneurship in prominent offices of the university, strengthening entrepreneurship societies and interactions with established entrepreneurs, and engagement with the private sector to contribute and promote entrepreneurship among students. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-04-06
Molecular characterization of microbial communities in the Sundays and Swartkops estuaries impacted by anthropogenic activities
- Kgomokhumo, Tlhoafalang Evah
- Authors: Kgomokhumo, Tlhoafalang Evah
- Date: 2022-04-06
- Subjects: Microbial ecology South Africa Sundays Estuary (Eastern Cape) , Microbial ecology South Africa Swartkops River Estuary , Estuarine health Effect of human beings on South Africa Sundays Estuary (Eastern Cape) , Estuarine health Effect of human beings on South Africa Swartkops River Estuary , Microorganisms South Africa Sundays Estuary (Eastern Cape) Molecular aspects , Microorganisms South Africa Swartkops River Estuary Molecular aspects , Eutrophication South Africa Sundays Estuary (Eastern Cape) , Eutrophication South Africa Swartkops River Estuary , Algal blooms South Africa Sundays Estuary (Eastern Cape) , Algal blooms South Africa Swartkops River Estuary
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290994 , vital:56806
- Description: Anthropogenic activities are of concern in estuarine systems as they are the main source of water degradation. Water pollution in estuaries is indicated by eutrophication and the presence of pathogens and bacterial indicators which affect biodiversity and energy flow. This study focused on two geographically linked estuaries, namely the Sundays and Swartkops Estuaries. The Sundays Estuary is primarily impacted by agricultural activities in the river catchment with increased nutrients levels, particularly of total oxidised nitrogen (TOxN), likely derived from these farming activities. In contrast, the Swartkops Estuary, which is heavily influenced by urban/industrial activities, reflected increased levels of phosphates likely from wastewater and sewage water contamination from residential areas, leaking pipes, and poorly managed sewage treatment plants. The central objective of this study was to assess microbial population profiles and diversity impacted by agricultural activities in Sundays Estuary and industrial/urban-influenced Swartkops Estuary using 16S and 18S rRNA gene metabarcoding. A distinct difference in eukaryotic composition and diversity was evident between the two sampling exercises in 2018 and 2019 in Sundays Estuary. The eutrophication of both the Sundays and Swartkops estuaries was evident in the repeated occurrences of bloom events. In the Sundays Estuary, a bloom of Heterosigma akashiwo was observed in 2018 whilst Cyclotella dominated the estuary in 2019. The Swartkops Estuary exhibited seasonal variation in phytoplankton composition with Bacillariophyceae blooms in the upper reaches of the estuary in summer and increased prevalence of Dinophyceae in spring. Bacterial taxonomic variation was also noted between the two contrasting estuaries. Although members of the Proteobacteria dominated both estuaries, Gammaproteobacteria were in increased abundance in Sundays Estuary while members of Alphaproteobacteria were in high relative abundance in the marine dominated Swartkops Estuary. Members of the Bacteroidetes were the second most abundant bacterial phylum in both estuaries. Bacterial indicators of agricultural anthropogenic impacts identified in Sundays Estuary included members of Sporichthyaceae, Erysipelotrichaceae, Nostocaceae, and NS11-12_marine_group while some taxa such as the Flavobacteriaceae, Cryomorphaceae, and Halieaceae reflected their capability in degrading the phytoplankton bloom biomass present in the estuary. The urban impacts on the Swartkops Estuary was reflected by the contamination of the estuary with potential pathogens including Aeromonas caviae, Vibrio fluvialis, Mycobacterium intracellulare, Vibrio cholerae, and Bacillus cereus. Bacterial community profiles of the major water inflow points into the Swartkops Estuary included members of the Burkholderiaceae, Rhodocyclaceae, Aeromonadaceae, and Arcobacteriaceae which are typically indicative of raw sewage contamination. The Motherwell canal, which runs through informal settlements, was the most polluted input source with high levels of anthropogenic nutrients and pathogenic bacteria. The Chatty river, which also runs through townships, recorded increased nutrient concentrations and low bacterial richness and diversity which was likely due to an Arthrospira bloom at the time of sampling. The overall results of this study identified sources of pollution in Sundays and Swartkops Estuaries and highlighted the impacts of anthropogenic inputs on microbial population profiles and diversity. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Kgomokhumo, Tlhoafalang Evah
- Date: 2022-04-06
- Subjects: Microbial ecology South Africa Sundays Estuary (Eastern Cape) , Microbial ecology South Africa Swartkops River Estuary , Estuarine health Effect of human beings on South Africa Sundays Estuary (Eastern Cape) , Estuarine health Effect of human beings on South Africa Swartkops River Estuary , Microorganisms South Africa Sundays Estuary (Eastern Cape) Molecular aspects , Microorganisms South Africa Swartkops River Estuary Molecular aspects , Eutrophication South Africa Sundays Estuary (Eastern Cape) , Eutrophication South Africa Swartkops River Estuary , Algal blooms South Africa Sundays Estuary (Eastern Cape) , Algal blooms South Africa Swartkops River Estuary
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290994 , vital:56806
- Description: Anthropogenic activities are of concern in estuarine systems as they are the main source of water degradation. Water pollution in estuaries is indicated by eutrophication and the presence of pathogens and bacterial indicators which affect biodiversity and energy flow. This study focused on two geographically linked estuaries, namely the Sundays and Swartkops Estuaries. The Sundays Estuary is primarily impacted by agricultural activities in the river catchment with increased nutrients levels, particularly of total oxidised nitrogen (TOxN), likely derived from these farming activities. In contrast, the Swartkops Estuary, which is heavily influenced by urban/industrial activities, reflected increased levels of phosphates likely from wastewater and sewage water contamination from residential areas, leaking pipes, and poorly managed sewage treatment plants. The central objective of this study was to assess microbial population profiles and diversity impacted by agricultural activities in Sundays Estuary and industrial/urban-influenced Swartkops Estuary using 16S and 18S rRNA gene metabarcoding. A distinct difference in eukaryotic composition and diversity was evident between the two sampling exercises in 2018 and 2019 in Sundays Estuary. The eutrophication of both the Sundays and Swartkops estuaries was evident in the repeated occurrences of bloom events. In the Sundays Estuary, a bloom of Heterosigma akashiwo was observed in 2018 whilst Cyclotella dominated the estuary in 2019. The Swartkops Estuary exhibited seasonal variation in phytoplankton composition with Bacillariophyceae blooms in the upper reaches of the estuary in summer and increased prevalence of Dinophyceae in spring. Bacterial taxonomic variation was also noted between the two contrasting estuaries. Although members of the Proteobacteria dominated both estuaries, Gammaproteobacteria were in increased abundance in Sundays Estuary while members of Alphaproteobacteria were in high relative abundance in the marine dominated Swartkops Estuary. Members of the Bacteroidetes were the second most abundant bacterial phylum in both estuaries. Bacterial indicators of agricultural anthropogenic impacts identified in Sundays Estuary included members of Sporichthyaceae, Erysipelotrichaceae, Nostocaceae, and NS11-12_marine_group while some taxa such as the Flavobacteriaceae, Cryomorphaceae, and Halieaceae reflected their capability in degrading the phytoplankton bloom biomass present in the estuary. The urban impacts on the Swartkops Estuary was reflected by the contamination of the estuary with potential pathogens including Aeromonas caviae, Vibrio fluvialis, Mycobacterium intracellulare, Vibrio cholerae, and Bacillus cereus. Bacterial community profiles of the major water inflow points into the Swartkops Estuary included members of the Burkholderiaceae, Rhodocyclaceae, Aeromonadaceae, and Arcobacteriaceae which are typically indicative of raw sewage contamination. The Motherwell canal, which runs through informal settlements, was the most polluted input source with high levels of anthropogenic nutrients and pathogenic bacteria. The Chatty river, which also runs through townships, recorded increased nutrient concentrations and low bacterial richness and diversity which was likely due to an Arthrospira bloom at the time of sampling. The overall results of this study identified sources of pollution in Sundays and Swartkops Estuaries and highlighted the impacts of anthropogenic inputs on microbial population profiles and diversity. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-04-06
Thicket expansion in a vachellia karroo-dominated landscape and its effect on herbaceous communities
- Authors: Khoza, Marina Rindzani
- Date: 2022-04-06
- Subjects: Savanna ecology South Africa , Forbs South Africa , Grasslands South Africa , Herbaceous plants South Africa , Vegetation dynamics South Africa , Forest canopies South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291015 , vital:56808
- Description: Grass and forb species found in savannas are highly diverse, contributing to the structure and function of the savanna system. Where mean annual rainfall is seasonal and high enough to support closed canopy vegetation such as forests or thickets, savannas can exist as an alternative stable state maintained by disturbances such as fire and browsing. Biotic and abiotic processes act on savanna and forest (or thicket) systems maintaining both their tree and herbaceous cover at levels that ensure their persistence in those states. Studies have shown that many semi-arid rangelands in South Africa have undergone a rapid increase in tree cover (of both native and non-native species) over the past several decades. This process of increasing tree cover in semi-arid savannas, termed bush encroachment, results in a biome shift, changing landscapes that were once grasslands with few trees to ones dominated by broad-leaved trees with fewer sun-adapted forbs and grasses. The aim of this study was to investigate the impact of changing woody cover and its associated changes in tree composition, tree canopy structure, light dynamics in the understory and herbaceous community composition on Endwell farm in the Eastern Cape. Canopy cover changes between the years 1949 and 2019 were analysed at 51 sites on the farm and related to historical rainfall patterns. There had been a general increase in tree cover over the past several decades on the farm, and many sites showed a change from open (0-15%) in 1949 to low (1635%), moderate (36-50%) and high (51-100%) canopy cover in 2019. In earlier years most sites had a canopy cover below 50%, and the higher canopy cover values (>65%) occurred in more recent decades. Canopy cover of ~ 50% was found to be rare in each decade. This suggests that ~50% canopy cover maybe a transient, unstable state. The period with the highest rate of canopy cover increase was 2002-2013, and this increase coincided with a high mean annual rainfall 10 years prior to 2002 and a high mean annual rainfall in most years between the 20022013 period. The period between 2002 and 2013 also had the highest number of sites transitioning from lower to higher tree canopy cover classes, indicating that rainfall may have been a factor driving bush encroachment during the past several decades. An increase in canopy cover (a decrease in light transmittance) was accompanied by changes in woody species composition during thicket formation. The low canopy cover (high light transmittance) sites were dominated by Vachellia karroo and Scutia myrtina trees, while high tree cover sites had fewer V. karroo and S. myrtina trees and were rather characterised by an abundance of thicket tree species. Species proportion, NMDS and dendrogram plots indicated that sites with a light transmittance range between 50-100% had similar tree species compositions, different from sites with light transmittances <50%. An increase in tree density was strongly correlated to an increase in canopy cover (from 2019 satellite imagery), density of trees > 3m, maximum height reached by trees, diversity of trees, total canopy volume, total canopy area and leaf area index (LAI), and a decrease in light transmittance. A structural equation model (SEM) was used to explore the relationships between canopy characteristics (maximum canopy area, canopy volume, tree diversity, density of trees, density of trees >3m, individual trees and maximum canopy height), aerial canopy cover in 2019, and light transmittance. The model explained 73% of the variation in light transmittance, mostly via the direct effect of canopy characteristics. Canopy characteristics had a strong influence on both aerial cover in 2019 and directly on light transmittance, but canopy cover in 2019 had a weak influence on light transmittance. The herbaceous layer was rich and dominated by C4 grasses such as Eragrostis plana, Sporobolus fimbriatus, Themeda triandra and Digitaria eriantha) and forbs including Hibiscus aethiopicus, Helichrysum dregeanum, Helichrysum nudifolium and Gerbera viridifolia at low canopy cover sites with high light transmittance. In contrast, high tree cover sites had fewer herbaceous species in general. Grass and forb species characteristic of these sites high canopy cover sites were Panicum maximum, Loudetia flavida, Pellaea viridis and Cyperus spp. Different sites with low light transmittance (<50%) had similar herbaceous species composition. Basal cover, richness, abundance and diversity of herbaceous plants decreased significantly with an increase in tree density, density of trees >3 m, canopy volume, canopy area, canopy cover, LAI, and increased significantly with increasing light transmittance. Most grasses had their highest densities at LAI <0.5, which was estimated to correspond to ~75% light transmittance and ~38% canopy cover and then started to decline thereafter. Herbaceous species basal cover was also highest at LAI <0.5. An SEM model indicated that herbaceous diversity, basal cover and richness responded both to light availability and to the structure of the woody vegetation directly (R2 = 0.53). While the effect of light transmittance on herbaceous communities was strong (0.41), there was little difference between the effect of light transmittance and canopy characteristics (-0.35) on herbaceous communities. Two possible threshold points, relating to two types of transitions in vegetation structure, could be deduced from this study. The first threshold occurred at canopy cover ~ 40% (LAI < ~ 0.5, light transmittance ~ 75%), at which point many of the common herbaceous species, including the dominant C4 grasses, began to decline in abundance while the composition remained characteristic of the savanna state. A canopy cover of less than ~ 40% at a site provides a suitable state for a high abundance of grass and forb species which help maintain an open system by facilitating fires. The second threshold marked a compositional shift between savanna and closed-canopy vegetation states. Savanna species (trees, grasses and forbs) dominated at high light transmittances (>50%) and were significantly reduced at low light transmittances (< 50%), indicating a possible species composition threshold at ~50% light transmittance at which a savanna state switches to a thicket (LAI ~ 1 and canopy cover ~70%). This point indicated the point where there was a significant difference in both tree and herbaceous plant compositions, with a marked reduction in the occurrence of C4 grasses at light transmittance <50%. Fire is supressed when the C4 grass layer is lost, and further thicket encroachment will take place causing complete canopy closure. Land managers in this system should start becoming concerned about a reduction in grass biomass when canopy cover reaches about 40% and would have to reduce tree cover before the threshold of 50% light transmittance (70% canopy cover from aerial photos) is reached to maintain a savanna system. , Thesis (MSc) -- Faculty of Science, Botany, 2022
- Full Text:
- Date Issued: 2022-04-06
Thicket expansion in a vachellia karroo-dominated landscape and its effect on herbaceous communities
- Authors: Khoza, Marina Rindzani
- Date: 2022-04-06
- Subjects: Savanna ecology South Africa , Forbs South Africa , Grasslands South Africa , Herbaceous plants South Africa , Vegetation dynamics South Africa , Forest canopies South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291015 , vital:56808
- Description: Grass and forb species found in savannas are highly diverse, contributing to the structure and function of the savanna system. Where mean annual rainfall is seasonal and high enough to support closed canopy vegetation such as forests or thickets, savannas can exist as an alternative stable state maintained by disturbances such as fire and browsing. Biotic and abiotic processes act on savanna and forest (or thicket) systems maintaining both their tree and herbaceous cover at levels that ensure their persistence in those states. Studies have shown that many semi-arid rangelands in South Africa have undergone a rapid increase in tree cover (of both native and non-native species) over the past several decades. This process of increasing tree cover in semi-arid savannas, termed bush encroachment, results in a biome shift, changing landscapes that were once grasslands with few trees to ones dominated by broad-leaved trees with fewer sun-adapted forbs and grasses. The aim of this study was to investigate the impact of changing woody cover and its associated changes in tree composition, tree canopy structure, light dynamics in the understory and herbaceous community composition on Endwell farm in the Eastern Cape. Canopy cover changes between the years 1949 and 2019 were analysed at 51 sites on the farm and related to historical rainfall patterns. There had been a general increase in tree cover over the past several decades on the farm, and many sites showed a change from open (0-15%) in 1949 to low (1635%), moderate (36-50%) and high (51-100%) canopy cover in 2019. In earlier years most sites had a canopy cover below 50%, and the higher canopy cover values (>65%) occurred in more recent decades. Canopy cover of ~ 50% was found to be rare in each decade. This suggests that ~50% canopy cover maybe a transient, unstable state. The period with the highest rate of canopy cover increase was 2002-2013, and this increase coincided with a high mean annual rainfall 10 years prior to 2002 and a high mean annual rainfall in most years between the 20022013 period. The period between 2002 and 2013 also had the highest number of sites transitioning from lower to higher tree canopy cover classes, indicating that rainfall may have been a factor driving bush encroachment during the past several decades. An increase in canopy cover (a decrease in light transmittance) was accompanied by changes in woody species composition during thicket formation. The low canopy cover (high light transmittance) sites were dominated by Vachellia karroo and Scutia myrtina trees, while high tree cover sites had fewer V. karroo and S. myrtina trees and were rather characterised by an abundance of thicket tree species. Species proportion, NMDS and dendrogram plots indicated that sites with a light transmittance range between 50-100% had similar tree species compositions, different from sites with light transmittances <50%. An increase in tree density was strongly correlated to an increase in canopy cover (from 2019 satellite imagery), density of trees > 3m, maximum height reached by trees, diversity of trees, total canopy volume, total canopy area and leaf area index (LAI), and a decrease in light transmittance. A structural equation model (SEM) was used to explore the relationships between canopy characteristics (maximum canopy area, canopy volume, tree diversity, density of trees, density of trees >3m, individual trees and maximum canopy height), aerial canopy cover in 2019, and light transmittance. The model explained 73% of the variation in light transmittance, mostly via the direct effect of canopy characteristics. Canopy characteristics had a strong influence on both aerial cover in 2019 and directly on light transmittance, but canopy cover in 2019 had a weak influence on light transmittance. The herbaceous layer was rich and dominated by C4 grasses such as Eragrostis plana, Sporobolus fimbriatus, Themeda triandra and Digitaria eriantha) and forbs including Hibiscus aethiopicus, Helichrysum dregeanum, Helichrysum nudifolium and Gerbera viridifolia at low canopy cover sites with high light transmittance. In contrast, high tree cover sites had fewer herbaceous species in general. Grass and forb species characteristic of these sites high canopy cover sites were Panicum maximum, Loudetia flavida, Pellaea viridis and Cyperus spp. Different sites with low light transmittance (<50%) had similar herbaceous species composition. Basal cover, richness, abundance and diversity of herbaceous plants decreased significantly with an increase in tree density, density of trees >3 m, canopy volume, canopy area, canopy cover, LAI, and increased significantly with increasing light transmittance. Most grasses had their highest densities at LAI <0.5, which was estimated to correspond to ~75% light transmittance and ~38% canopy cover and then started to decline thereafter. Herbaceous species basal cover was also highest at LAI <0.5. An SEM model indicated that herbaceous diversity, basal cover and richness responded both to light availability and to the structure of the woody vegetation directly (R2 = 0.53). While the effect of light transmittance on herbaceous communities was strong (0.41), there was little difference between the effect of light transmittance and canopy characteristics (-0.35) on herbaceous communities. Two possible threshold points, relating to two types of transitions in vegetation structure, could be deduced from this study. The first threshold occurred at canopy cover ~ 40% (LAI < ~ 0.5, light transmittance ~ 75%), at which point many of the common herbaceous species, including the dominant C4 grasses, began to decline in abundance while the composition remained characteristic of the savanna state. A canopy cover of less than ~ 40% at a site provides a suitable state for a high abundance of grass and forb species which help maintain an open system by facilitating fires. The second threshold marked a compositional shift between savanna and closed-canopy vegetation states. Savanna species (trees, grasses and forbs) dominated at high light transmittances (>50%) and were significantly reduced at low light transmittances (< 50%), indicating a possible species composition threshold at ~50% light transmittance at which a savanna state switches to a thicket (LAI ~ 1 and canopy cover ~70%). This point indicated the point where there was a significant difference in both tree and herbaceous plant compositions, with a marked reduction in the occurrence of C4 grasses at light transmittance <50%. Fire is supressed when the C4 grass layer is lost, and further thicket encroachment will take place causing complete canopy closure. Land managers in this system should start becoming concerned about a reduction in grass biomass when canopy cover reaches about 40% and would have to reduce tree cover before the threshold of 50% light transmittance (70% canopy cover from aerial photos) is reached to maintain a savanna system. , Thesis (MSc) -- Faculty of Science, Botany, 2022
- Full Text:
- Date Issued: 2022-04-06
An investigation into the force-EMG relationship for static and dynamic exertions
- Koekemoer, Wesley Agosthinho
- Authors: Koekemoer, Wesley Agosthinho
- Date: 2022-04-06
- Subjects: Electromyography , Force and energy , Muscles Physiology , Biomechanics , Muscle contraction , Isometric exercise , Isotonic exercise , Static and dynamic exertions
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291076 , vital:56816
- Description: The force-EMG relationship has multiple applications in varying fields of study and practice. One such application is the development of safety guidelines and regulations. Current guidelines are based on static muscle actions even though the majority of tasks encountered in industry are dynamic in nature. This may have negative implications for the health, safety, and productivity of workers as regulations based on static muscle actions may place higher force demands on manual labourers compared to what would be expected if regulations were based on dynamic muscle actions. Regulations based on dynamic muscle actions may be more effective in worker safety as the nature of the regulation matches that of the demand. Few studies have investigated the force-EMG relationship during dynamic muscle actions and the few that do exist have reported contradictory / mixed results. Therefore, the purpose of this study was to: 1) gain an understanding of EMG responses at different load levels, and 2) show how the relationship differs between static and dynamic muscle actions. A two-factorial repeated-measures experiment was developed for this study. Eighteen experimental conditions, utilizing six load levels (0%, 20%, 40%, 60%, 80%, and 100% of maximum voluntary force) for each of the three muscle actions (isometric, concentric and eccentric). Surface EMG responses were obtained under these conditions by repeatedly dorsiflexing and plantarflexing the foot, thus activating the soleus muscle. A maximum voluntary exertion on an isokinetic dynamometer determined the maximum force level, based on which the sub-maximal loads were calculated and added to a pulley system. 31 student participants were recruited for this experiment which was conducted over two sessions – one information and habituation session, and one experimental session. The EMG data recorded were processed and checked for normality and outliers. The data was then analysed via a General Linear Model analysis to determine the effect of exertion type and of load level on the muscle activity. Significant differences were identified at p<0.05 and followed by a Tukey post-hoc test. Correlation analyses were also conducted to determine the relationship between the force and EMG at all three exertion types. All dependent measures showed that as the load level increased so did the sEMG amplitude for all muscle actions. Muscle actions differed significantly between majority of six force levels. Correlations between the load levels and sEMG amplitude for each muscle action indicated a significant correlation with a moderate strength. The conclusion draws from this study that there is a positive correlation between force and sEMG amplitude, at all load levels, with a moderate strength. However, the muscle actions differed significantly from each other. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Koekemoer, Wesley Agosthinho
- Date: 2022-04-06
- Subjects: Electromyography , Force and energy , Muscles Physiology , Biomechanics , Muscle contraction , Isometric exercise , Isotonic exercise , Static and dynamic exertions
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291076 , vital:56816
- Description: The force-EMG relationship has multiple applications in varying fields of study and practice. One such application is the development of safety guidelines and regulations. Current guidelines are based on static muscle actions even though the majority of tasks encountered in industry are dynamic in nature. This may have negative implications for the health, safety, and productivity of workers as regulations based on static muscle actions may place higher force demands on manual labourers compared to what would be expected if regulations were based on dynamic muscle actions. Regulations based on dynamic muscle actions may be more effective in worker safety as the nature of the regulation matches that of the demand. Few studies have investigated the force-EMG relationship during dynamic muscle actions and the few that do exist have reported contradictory / mixed results. Therefore, the purpose of this study was to: 1) gain an understanding of EMG responses at different load levels, and 2) show how the relationship differs between static and dynamic muscle actions. A two-factorial repeated-measures experiment was developed for this study. Eighteen experimental conditions, utilizing six load levels (0%, 20%, 40%, 60%, 80%, and 100% of maximum voluntary force) for each of the three muscle actions (isometric, concentric and eccentric). Surface EMG responses were obtained under these conditions by repeatedly dorsiflexing and plantarflexing the foot, thus activating the soleus muscle. A maximum voluntary exertion on an isokinetic dynamometer determined the maximum force level, based on which the sub-maximal loads were calculated and added to a pulley system. 31 student participants were recruited for this experiment which was conducted over two sessions – one information and habituation session, and one experimental session. The EMG data recorded were processed and checked for normality and outliers. The data was then analysed via a General Linear Model analysis to determine the effect of exertion type and of load level on the muscle activity. Significant differences were identified at p<0.05 and followed by a Tukey post-hoc test. Correlation analyses were also conducted to determine the relationship between the force and EMG at all three exertion types. All dependent measures showed that as the load level increased so did the sEMG amplitude for all muscle actions. Muscle actions differed significantly between majority of six force levels. Correlations between the load levels and sEMG amplitude for each muscle action indicated a significant correlation with a moderate strength. The conclusion draws from this study that there is a positive correlation between force and sEMG amplitude, at all load levels, with a moderate strength. However, the muscle actions differed significantly from each other. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2022
- Full Text:
- Date Issued: 2022-04-06
Academic or ‘zoombie’? Characterizing sleep quality, work and lifestyle behaviours among a cohort of South African academic staff during the Covid-19 pandemic
- Authors: Le Grange, Sarah-Ann
- Date: 2022-04-06
- Subjects: Sleep-wake cycle South Africa Eastern Cape , Sleep Physiological aspects , Lifestyles Health aspects South Africa Eastern Cape , COVID-19 Pandemic, 2020- Influence , Work environment Psychological aspects , Work environment Physiological aspects , College teachers Workload South Africa Eastern Cape , Pittsburgh Sleep Quality Index (PSQI)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291099 , vital:56818
- Description: Working in academe is characterized by high work demands, long and late working hours and balancing multiple roles. This often leaves academic staff (interchangeably referred to as ‘academics’ and ‘staff’) with limited time to prioritize adequate rest and sleep. While sufficient sleep is important for general well-being and work performance, it may be important for academics given the cognitive and interactive nature of their work. However, limited research has characterized sleep behaviours and sleep quality in academic staff globally and specifically in South Africa (SA). Further, research shows that academics from different academic ranks and genders differ in their work experiences but less is known about whether these factors affect their sleep and lifestyle factors. Over and above the demands of academic work, the current study was conducted during COVID-19, which saw unprecedented change in workloads for academic staff due to online teaching and learning. Additionally, the pandemic has been associated with poorer sleep quality and lifestyle behaviours in the general population, but very few studies have explored this in the context of academics. Thus, this study aimed to characterize the sleep quality, work and lifestyle factors among academics from a university in the Eastern Cape province of SA and determine the effects of gender and academic rank on these measures. Additionally, the study aimed to determine the impact of COVID-19 on sleep and work-related factors of this group. This study adopted a cross-sectional design and made use of an online questionnaire that was distributed to all academics employed at the institution via email. The data collection occurred over an 8-week testing period between August and September of 2020. The questionnaire explored sociodemographic, work and lifestyle characteristics, while the characteristics of sleep and sleep quality were explored with the Pittsburgh Sleep Quality Index (PSQI). Additionally, an open-ended section was included to determine the impact of COVID-19-related changes on sleep and work. The questionnaire responses were analyzed with descriptive and inferential statistics and the open-ended questions were analyzed with thematic analyses. A total of 84 respondents completed the questionnaire. On average, sleep quality was poor (global score of 7.09 ± 3.8), the reported sleep duration was short (6.41 ± 1.06 hrs) and the group was classified as overweight according to median BMI (26.67 [23.8-2 29.45] kg/m2). Over a third (35.71%) of academic staff reported not meeting physical activity guidelines and reported using screens one hour prior to bed every night during the week (76.19%) and the weekend (67.88%). Staff also worked long total weekly work hours (54.25 ± 11). Female academics had a poorer sleep quality (p = 0.035), spent a longer time in bed (p = 0.04), experienced more bad dreams (p = <0.01), had their last serving of alcohol earlier (p = 0.04) and worked less weekday (p = 0.04) and less total weekly (p = 0.02) hours compared to male academics. Professorship-level academics were significantly older than junior- and senior-level academics (p = <0.01) while senior-level academics had a poorer PSQI compared to professorship-level academics (p = 0.03). The thematic analysis showed that home environment, neighbourhood noise, work and mental health were the main emerging factors that disturbed sleep. The thematic analysis showed that, in relation to the impact of COVID19, sleep schedules changed and sleep duration and sleep quality improved or got worse. Respondents reported their work hours increasing, work schedules becoming less routine while working from home, dealing with the challenges of working online and experiencing worry, stress and anxiety due to the pandemic. The study highlights that, in the context of lockdown and having to work and teach online from home, academics reported poor quality sleep and short sleep duration. Further, on average, the sample reported working extensive hours and unhealthy lifestyle behaviours. The sleep health, nature of work and overall lifestyles of academic staff deserves more research attention, given the importance of their work and the impact that inadequate sleep could have on academics’ health and work performance. Sleep quality was worse for females and mid-career academics, suggesting that their sleep quality may be at greater risk than other sub-groups. However, the reasons for these differences need to be explored in future studies. The findings contribute to the narrative that academe involves numerous demands and supports previous research that has suggested that academics’ sleep is insufficient. Furthermore, COVID-19 had an impact on staff’s sleep, with staff reporting changes in their sleep quality and duration. The pandemic impacted work of academics by presenting novel demands related to online teaching, intensifying demands overall and disrupting work routines. However, future research is needed to understand academics’ sleep behaviours, work and lifestyles, especially in South Africa. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Le Grange, Sarah-Ann
- Date: 2022-04-06
- Subjects: Sleep-wake cycle South Africa Eastern Cape , Sleep Physiological aspects , Lifestyles Health aspects South Africa Eastern Cape , COVID-19 Pandemic, 2020- Influence , Work environment Psychological aspects , Work environment Physiological aspects , College teachers Workload South Africa Eastern Cape , Pittsburgh Sleep Quality Index (PSQI)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291099 , vital:56818
- Description: Working in academe is characterized by high work demands, long and late working hours and balancing multiple roles. This often leaves academic staff (interchangeably referred to as ‘academics’ and ‘staff’) with limited time to prioritize adequate rest and sleep. While sufficient sleep is important for general well-being and work performance, it may be important for academics given the cognitive and interactive nature of their work. However, limited research has characterized sleep behaviours and sleep quality in academic staff globally and specifically in South Africa (SA). Further, research shows that academics from different academic ranks and genders differ in their work experiences but less is known about whether these factors affect their sleep and lifestyle factors. Over and above the demands of academic work, the current study was conducted during COVID-19, which saw unprecedented change in workloads for academic staff due to online teaching and learning. Additionally, the pandemic has been associated with poorer sleep quality and lifestyle behaviours in the general population, but very few studies have explored this in the context of academics. Thus, this study aimed to characterize the sleep quality, work and lifestyle factors among academics from a university in the Eastern Cape province of SA and determine the effects of gender and academic rank on these measures. Additionally, the study aimed to determine the impact of COVID-19 on sleep and work-related factors of this group. This study adopted a cross-sectional design and made use of an online questionnaire that was distributed to all academics employed at the institution via email. The data collection occurred over an 8-week testing period between August and September of 2020. The questionnaire explored sociodemographic, work and lifestyle characteristics, while the characteristics of sleep and sleep quality were explored with the Pittsburgh Sleep Quality Index (PSQI). Additionally, an open-ended section was included to determine the impact of COVID-19-related changes on sleep and work. The questionnaire responses were analyzed with descriptive and inferential statistics and the open-ended questions were analyzed with thematic analyses. A total of 84 respondents completed the questionnaire. On average, sleep quality was poor (global score of 7.09 ± 3.8), the reported sleep duration was short (6.41 ± 1.06 hrs) and the group was classified as overweight according to median BMI (26.67 [23.8-2 29.45] kg/m2). Over a third (35.71%) of academic staff reported not meeting physical activity guidelines and reported using screens one hour prior to bed every night during the week (76.19%) and the weekend (67.88%). Staff also worked long total weekly work hours (54.25 ± 11). Female academics had a poorer sleep quality (p = 0.035), spent a longer time in bed (p = 0.04), experienced more bad dreams (p = <0.01), had their last serving of alcohol earlier (p = 0.04) and worked less weekday (p = 0.04) and less total weekly (p = 0.02) hours compared to male academics. Professorship-level academics were significantly older than junior- and senior-level academics (p = <0.01) while senior-level academics had a poorer PSQI compared to professorship-level academics (p = 0.03). The thematic analysis showed that home environment, neighbourhood noise, work and mental health were the main emerging factors that disturbed sleep. The thematic analysis showed that, in relation to the impact of COVID19, sleep schedules changed and sleep duration and sleep quality improved or got worse. Respondents reported their work hours increasing, work schedules becoming less routine while working from home, dealing with the challenges of working online and experiencing worry, stress and anxiety due to the pandemic. The study highlights that, in the context of lockdown and having to work and teach online from home, academics reported poor quality sleep and short sleep duration. Further, on average, the sample reported working extensive hours and unhealthy lifestyle behaviours. The sleep health, nature of work and overall lifestyles of academic staff deserves more research attention, given the importance of their work and the impact that inadequate sleep could have on academics’ health and work performance. Sleep quality was worse for females and mid-career academics, suggesting that their sleep quality may be at greater risk than other sub-groups. However, the reasons for these differences need to be explored in future studies. The findings contribute to the narrative that academe involves numerous demands and supports previous research that has suggested that academics’ sleep is insufficient. Furthermore, COVID-19 had an impact on staff’s sleep, with staff reporting changes in their sleep quality and duration. The pandemic impacted work of academics by presenting novel demands related to online teaching, intensifying demands overall and disrupting work routines. However, future research is needed to understand academics’ sleep behaviours, work and lifestyles, especially in South Africa. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2022
- Full Text:
- Date Issued: 2022-04-06
A novel o/w microemulsion fixed dose combination of efavirenz, emtricitabine and tenofovir disoproxil fumarate: development and characterisation
- Authors: Mabvira, Samantha
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232925 , vital:50038
- Description: Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Mabvira, Samantha
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232925 , vital:50038
- Description: Thesis (MSc) -- Faculty of Pharmacy, Pharmacy, 2022
- Full Text:
- Date Issued: 2022-04-06
Financial technology and bank risk-taking behavior: a case of selected South African banks
- Authors: Magula, Zizipho
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/234206 , vital:50172
- Description: Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Magula, Zizipho
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/234206 , vital:50172
- Description: Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2022
- Full Text:
- Date Issued: 2022-04-06
The assessment of degradation state in Ecological Infrastructure and prioritisation for rehabilitation and drought mitigation in the Tsitsa River Catchment
- Authors: Mahlaba, Bawinile
- Date: 2022-04-06
- Subjects: Environmental degradation South Africa Eastern Cape , Restoration ecology South Africa Eastern Cape , Climate change mitigation South Africa Eastern Cape , Droughts South Africa Eastern Cape , South African National Biodiversity Institute , Sustainable development South Africa Eastern Cape , Watersheds , Ecological Infrastructure (EI) , Tsitsa River Catchment
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/202138 , vital:46470
- Description: Ecosystem degradation is a serious concern globally, including in South Africa, because of the potential adverse impacts on food security, livelihoods, climate change, biodiversity, and ecosystem services. Ecosystem degradation can result in flow alteration in the landscape through changes in the hydrological regime. The study adopts the South African National Biodiversity Institute (SANBI) Framework of Investing in Ecological Infrastructure (EI) to prioritise the restoration of degraded ecosystems and maintain ecosystem structures and functions. This study aims to assess how EI (specifically wetlands, grassland, abandoned cultivated fields, and riparian zone) can facilitate drought mitigation: to assess land degradation status and identify priority EI areas that can be restored to improve the drought mitigation capacity. Two assessment methods were used in this study. Firstly, the Trends.Earth tool was used to assess degradation and land cover change from the year 2000-2015 in Tsitsa catchment, through assessment of Sustainable Development Goal degradation indicator (SDG15.3.1) at a resolution of 300 m. The degradation indicator uses information from three sub-indicators: Productivity, Landcover and Soil Organic Carbon to compute degraded areas. The degraded areas need to be restored and rehabilitated to maintain the flow of essential ecosystems services provided by EI. The second assessment used the Analytical Hierarchy Process (AHP), which integrates stakeholder inputs into a multi-criteria decision analysis (MCDA). The AHP is a useful decision support system that considers a range of quantitative and qualitative alternatives in making a final decision to solve complex problems. As part of the AHP analysis, participatory mapping using Participatory Geographic Information System was conducted to obtain stakeholder inputs for prioritising restoration of the key EI categories (wetlands, grassland, abandoned cultivated fields, and riparian zone) in the catchment. During the participatory mapping, communities prioritised the key EI based on three criteria: (1) ecosystem health, (2) water provisioning and (3) social benefits. The AHP method was used in ArcGIS to prioritise suitable key EI restoration areas with high potential to increase water recharge and storage, contribute to drought mitigation and ecosystem services for the catchment. The prioritisation of EI for community livelihoods in the AHP analysis included all three main criteria. In comparison, the prioritisation of suitable key EI restoration areas for flow regulations was based on two criteria: ecosystem health and water provisioning. The land degradation indicator showed that approximately 54% of the catchment is stable, 41% is degraded land, and 5% of the area has improved over the assessment period (15 years). The degradation status in the EI suggests that more than half (>50%) of each EI category is stable, but there are areas showing signs of degradation, including 43% of grasslands degraded and 39% of wetlands, cultivated lands, and riparian zones also degraded. Degradation is dominant in the upper (T35B and T3C) and lower (T35K, T35L and T35M) parts of the catchments. The three criteria used by the stakeholders in the prioritisation process of the key EI were assigned 12 spatial attributes (the catchment characteristics about the study area in relation to the criteria) to indicate relevant information needed for selecting suitable restoration areas to enhance flow regulation. The AHP analysis results identified approximately 63% (17,703 ha) of wetlands, 88% (235,829 ha) of grasslands, 78% (13,608 ha) of abandoned cultivated fields and 93% (3,791 ha) of the riparian zones as suitable areas for restoration to mitigate drought impact through flow regulation. Also, the suitability results showed 63% (17,703 ha) of wetlands, 58% (2,203 ha) of riparian zones, 68% (11,745 ha) of abandoned cultivated fields and 46% (122,285 ha) of grasslands as suitable restoration areas for improving ecosystem services for community livelihoods. The AHP analysis identified more than 39-43% (of the degraded EI indicated by the Trends.Earth analysis) areas that are suitable for restoration, because key EI plays a significant role in flow regulation and people’s livelihoods, especially when they are managed, maintained, and restored to good health conditions. Therefore, the prioritized EI areas should be either maintained, managed, rehabilitated or restored. The major distinct causes of land degradation are woody encroachment in grasslands, invasion of alien plants on abandoned cultivated fields and soil erosion in the catchment. The most suitable EI areas recommended for restoration are those natural resources near local communities, which provide essential ecosystem services to sustain their livelihood. Therefore, degraded EI in the T35 catchments should be restored and maintained to improve livelihood and mitigate drought impacts. The study pointed out how the key selected ecological infrastructure can help mitigate the impacts of droughts and improve human livelihood. The study contributes towards the important concept of investing in ecological infrastructure to improve the social, environmental, and economic benefits. , Thesis (MSc) -- Faculty of Science, Institute for Water Research, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Mahlaba, Bawinile
- Date: 2022-04-06
- Subjects: Environmental degradation South Africa Eastern Cape , Restoration ecology South Africa Eastern Cape , Climate change mitigation South Africa Eastern Cape , Droughts South Africa Eastern Cape , South African National Biodiversity Institute , Sustainable development South Africa Eastern Cape , Watersheds , Ecological Infrastructure (EI) , Tsitsa River Catchment
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/202138 , vital:46470
- Description: Ecosystem degradation is a serious concern globally, including in South Africa, because of the potential adverse impacts on food security, livelihoods, climate change, biodiversity, and ecosystem services. Ecosystem degradation can result in flow alteration in the landscape through changes in the hydrological regime. The study adopts the South African National Biodiversity Institute (SANBI) Framework of Investing in Ecological Infrastructure (EI) to prioritise the restoration of degraded ecosystems and maintain ecosystem structures and functions. This study aims to assess how EI (specifically wetlands, grassland, abandoned cultivated fields, and riparian zone) can facilitate drought mitigation: to assess land degradation status and identify priority EI areas that can be restored to improve the drought mitigation capacity. Two assessment methods were used in this study. Firstly, the Trends.Earth tool was used to assess degradation and land cover change from the year 2000-2015 in Tsitsa catchment, through assessment of Sustainable Development Goal degradation indicator (SDG15.3.1) at a resolution of 300 m. The degradation indicator uses information from three sub-indicators: Productivity, Landcover and Soil Organic Carbon to compute degraded areas. The degraded areas need to be restored and rehabilitated to maintain the flow of essential ecosystems services provided by EI. The second assessment used the Analytical Hierarchy Process (AHP), which integrates stakeholder inputs into a multi-criteria decision analysis (MCDA). The AHP is a useful decision support system that considers a range of quantitative and qualitative alternatives in making a final decision to solve complex problems. As part of the AHP analysis, participatory mapping using Participatory Geographic Information System was conducted to obtain stakeholder inputs for prioritising restoration of the key EI categories (wetlands, grassland, abandoned cultivated fields, and riparian zone) in the catchment. During the participatory mapping, communities prioritised the key EI based on three criteria: (1) ecosystem health, (2) water provisioning and (3) social benefits. The AHP method was used in ArcGIS to prioritise suitable key EI restoration areas with high potential to increase water recharge and storage, contribute to drought mitigation and ecosystem services for the catchment. The prioritisation of EI for community livelihoods in the AHP analysis included all three main criteria. In comparison, the prioritisation of suitable key EI restoration areas for flow regulations was based on two criteria: ecosystem health and water provisioning. The land degradation indicator showed that approximately 54% of the catchment is stable, 41% is degraded land, and 5% of the area has improved over the assessment period (15 years). The degradation status in the EI suggests that more than half (>50%) of each EI category is stable, but there are areas showing signs of degradation, including 43% of grasslands degraded and 39% of wetlands, cultivated lands, and riparian zones also degraded. Degradation is dominant in the upper (T35B and T3C) and lower (T35K, T35L and T35M) parts of the catchments. The three criteria used by the stakeholders in the prioritisation process of the key EI were assigned 12 spatial attributes (the catchment characteristics about the study area in relation to the criteria) to indicate relevant information needed for selecting suitable restoration areas to enhance flow regulation. The AHP analysis results identified approximately 63% (17,703 ha) of wetlands, 88% (235,829 ha) of grasslands, 78% (13,608 ha) of abandoned cultivated fields and 93% (3,791 ha) of the riparian zones as suitable areas for restoration to mitigate drought impact through flow regulation. Also, the suitability results showed 63% (17,703 ha) of wetlands, 58% (2,203 ha) of riparian zones, 68% (11,745 ha) of abandoned cultivated fields and 46% (122,285 ha) of grasslands as suitable restoration areas for improving ecosystem services for community livelihoods. The AHP analysis identified more than 39-43% (of the degraded EI indicated by the Trends.Earth analysis) areas that are suitable for restoration, because key EI plays a significant role in flow regulation and people’s livelihoods, especially when they are managed, maintained, and restored to good health conditions. Therefore, the prioritized EI areas should be either maintained, managed, rehabilitated or restored. The major distinct causes of land degradation are woody encroachment in grasslands, invasion of alien plants on abandoned cultivated fields and soil erosion in the catchment. The most suitable EI areas recommended for restoration are those natural resources near local communities, which provide essential ecosystem services to sustain their livelihood. Therefore, degraded EI in the T35 catchments should be restored and maintained to improve livelihood and mitigate drought impacts. The study pointed out how the key selected ecological infrastructure can help mitigate the impacts of droughts and improve human livelihood. The study contributes towards the important concept of investing in ecological infrastructure to improve the social, environmental, and economic benefits. , Thesis (MSc) -- Faculty of Science, Institute for Water Research, 2022
- Full Text:
- Date Issued: 2022-04-06
The regulation of privacy on cloud computing services in terms of the Protection of Personal Information Act 4 of 2013
- Authors: Malahleka, Mthuthukisi
- Date: 2022-04-06
- Subjects: South Africa. Protection of Personal Information Act, 2013 , Cloud computing Law and legislation South Africa , Data protection Law and legislation South Africa , Personal information management South Africa , Data privacy South Africa , Computer security Law and legislation South Africa , General Data Protection Regulation (GDPR)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290731 , vital:56779
- Description: There is a relatively new development in Information Technology (IT) space known as cloud computing, software and service delivered remotely through the Internet without installing software on a computer. Cloud computing has quickly gathered steam as one of the most prominent topics in IT, and indeed within the business sector as a whole. Cloud computing is one such development associated with opportunities and benefits, especially in the commercial sector. Due to the development of IT and many businesses adopting e-commerce business-related strategies, cloud computing has revolutionised how personal information is processed. The advent of cloud computing as a mechanism to process personal information has brought many legal challenges for protecting the right to privacy enshrined under section 14 of the South African Constitution, which is a vulnerable part of one’s personality right. The right to privacy has long been protected even before adopting the Constitution under the common law of delict (actio iniuriarumn). As the adoption rate of cloud computing services by businesses continues to increase, the legal considerations and risks become more prevalent. The lawmakers struggle to keep pace with the rapidly changing technological advancements, at least for now. Both the common law and the Constitution could not address all the legal aspects of data protection and the adoption of cloud computing services hence the promulgation of the Protection of Personal Information Act 4 of 2013 (POPI Act). The POPI Act’s main objective is to protect the personal information of both natural and juristic persons. Personal information about an individual forms part of privacy. Unlawful processing of such personal information is a violation of the right to privacy of an individual. It is now widely recognised that the unregulated processing of personal information significantly impacts fundamental human rights like privacy, personality, and autonomy. A close analysis of cloud computing regulation is necessary, as legal protection mechanisms must safeguard the processing of personal information and establish extraterritorial jurisdiction to regulate the use of cloud computing within national legislation as cloud computing provides a transnational characteristic on the cross-border flow of personal information. In this thesis, a question is asked on whether the current data protection laws in South Africa on protecting the right to privacy in the cloud computing services context are adequate. The analysis will determine whether the overlaps between these pieces of data protection laws are competent to deal with the ever-increasing threats on the right to privacy and if they meet the international data protection standards set by the European Union’s General Data Protection Regulation (GDPR). The research seeks to analyse and reveal the shortcomings under the Constitution and the common law that led to adopting the POPI Act by studying the regulation of cloud computing services. This analysis will determine the shortcomings of the POPI Act as well in the context of cloud computing. The research will then follow a comparative analysis of the POPI Act and the GDPR to determine the application of the GDPR on international data breaches and compare its provisions with the POPI Act in the context of cloud computing. Finally, the research will address the question as to whether a multi-faceted approach, which includes a Model Law on cloud computing, would be an appropriate starting point setting out requirements for the use of this technology can be sufficient in protecting data subjects. And as cloud computing risks are not only a national but also a global problem, South Africa needs to look at the option of entering into mutual agreements with other countries and organisations to regulate cloud computing at an international level. , Thesis (LLM) -- Faculty of Law, Law, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Malahleka, Mthuthukisi
- Date: 2022-04-06
- Subjects: South Africa. Protection of Personal Information Act, 2013 , Cloud computing Law and legislation South Africa , Data protection Law and legislation South Africa , Personal information management South Africa , Data privacy South Africa , Computer security Law and legislation South Africa , General Data Protection Regulation (GDPR)
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290731 , vital:56779
- Description: There is a relatively new development in Information Technology (IT) space known as cloud computing, software and service delivered remotely through the Internet without installing software on a computer. Cloud computing has quickly gathered steam as one of the most prominent topics in IT, and indeed within the business sector as a whole. Cloud computing is one such development associated with opportunities and benefits, especially in the commercial sector. Due to the development of IT and many businesses adopting e-commerce business-related strategies, cloud computing has revolutionised how personal information is processed. The advent of cloud computing as a mechanism to process personal information has brought many legal challenges for protecting the right to privacy enshrined under section 14 of the South African Constitution, which is a vulnerable part of one’s personality right. The right to privacy has long been protected even before adopting the Constitution under the common law of delict (actio iniuriarumn). As the adoption rate of cloud computing services by businesses continues to increase, the legal considerations and risks become more prevalent. The lawmakers struggle to keep pace with the rapidly changing technological advancements, at least for now. Both the common law and the Constitution could not address all the legal aspects of data protection and the adoption of cloud computing services hence the promulgation of the Protection of Personal Information Act 4 of 2013 (POPI Act). The POPI Act’s main objective is to protect the personal information of both natural and juristic persons. Personal information about an individual forms part of privacy. Unlawful processing of such personal information is a violation of the right to privacy of an individual. It is now widely recognised that the unregulated processing of personal information significantly impacts fundamental human rights like privacy, personality, and autonomy. A close analysis of cloud computing regulation is necessary, as legal protection mechanisms must safeguard the processing of personal information and establish extraterritorial jurisdiction to regulate the use of cloud computing within national legislation as cloud computing provides a transnational characteristic on the cross-border flow of personal information. In this thesis, a question is asked on whether the current data protection laws in South Africa on protecting the right to privacy in the cloud computing services context are adequate. The analysis will determine whether the overlaps between these pieces of data protection laws are competent to deal with the ever-increasing threats on the right to privacy and if they meet the international data protection standards set by the European Union’s General Data Protection Regulation (GDPR). The research seeks to analyse and reveal the shortcomings under the Constitution and the common law that led to adopting the POPI Act by studying the regulation of cloud computing services. This analysis will determine the shortcomings of the POPI Act as well in the context of cloud computing. The research will then follow a comparative analysis of the POPI Act and the GDPR to determine the application of the GDPR on international data breaches and compare its provisions with the POPI Act in the context of cloud computing. Finally, the research will address the question as to whether a multi-faceted approach, which includes a Model Law on cloud computing, would be an appropriate starting point setting out requirements for the use of this technology can be sufficient in protecting data subjects. And as cloud computing risks are not only a national but also a global problem, South Africa needs to look at the option of entering into mutual agreements with other countries and organisations to regulate cloud computing at an international level. , Thesis (LLM) -- Faculty of Law, Law, 2022
- Full Text:
- Date Issued: 2022-04-06
Trace element and sulphur isotope variations of sulphides in the Koperberg Suite, O’okiep Copper District, Namaqualand, South Africa: implications for formation of sulphides and the role of crustal sulphur assimilation
- Authors: Marima, Edmore
- Date: 2022-04-06
- Subjects: Sulfur Isotopes , Magmatism South Africa Namaqualand , Sulfides , Koperberg Suite (South Africa) , Copper sulfide , Sulfur Absorption and adsorption
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291117 , vital:56820
- Description: The major economic copper sulphide deposits hosted in the late Mesoproterozoic intrusions of the Koperberg Suite in the O’okiep Copper District immediately overlie sulphur-bearing paragneisses of the Khurisberg Subgroup in an otherwise low-sulphur granitic basement. The dominant sulphide assemblage (chalcopyrite and bornite) hosted in the Koperberg Suite is also atypical of the intermediate solid solution (iss) assemblage (chalcopyrite and pyrrhotite) observed in most Cu-Ni magmatic sulphide deposits. This study presents sulphur isotope and in-situ trace element analysis of sulphides from the Koperberg Suite and the Khurisberg Subgroup with the view of placing constraints on the role of sulphide-bearing supracrustal metasedimentary of the Khurisberg Subgroup as a source of additional sulphur in the genesis of these deposits, and ore-forming (sulphide formation) processes which result in trace element variations registered by sulphides hosted in the Koperberg Suite. The high concentrations (up to 2100 ppm) of monosulphide solid solution (mss)-incompatible trace elements (e.g., Te, Se, Bi, Ag, Pb), and the depletion in Ni and Co (<40 ppm) of sulphides hosted in the Koperberg Suite are instead consistent with the derivation of such sulphides from a Cu-rich sulphide melt which segregated from a Ni-rich sulphide melt prior to magma emplacement in the middle crust, in agreement with one of the petrogenetic models for the Koperberg Suite proposed in the existing literature. The low S/Se ratios ( ̴650-10300) of sulphides hosted in the Koperberg Suite and the high S/Se ratios ( ̴18800-56000) registered by the main sulphide phase (pyrite) in the Khurisberg Subgroup argues against crustal contamination of the Koperberg Suite magmas by the Khurisberg Subgroup. The S/Se and Cu/S ratios of coexisting bornite and chalcopyrite hosted in the Koperberg Suite are positively correlated with the bornite modal abundance in the Koperberg Suite. Such trends are interpreted to be consistent with progressive oxidation of sulphide melt, a process which results in the crystallisation of iss-bornite assemblage and/or replacement of iss with bornite due to the enrichment of Cu and depletion in S of the sulphide melt. The oxidation of sulphide melt is likely to have been effectuated by the fractional crystallisation of mss in a prior sulphide melt segregation event and/or the fractional crystallisation of Fe2+-dominated silicate phases. Fractionation of the Cu-rich melt sulphide melt (segregated from mss) also tends to enrich the residual sulphide melts in Se. Thus, the chalcopyrite-dominated assemblage with S/Se ratios of ̴1300-10200 observed in the less basic rocks in the Koperberg Suite (leucodiorites and leuconorites) is interpreted to have formed from the least evolved sulphide melt, whereas the bornite-dominated assemblage with S/Se ratios of ̴650-5500 observed in the more mafic members of the Koperberg Suite (orthopyroxenites and norites) is interpreted to have formed from the most evolved sulphide melt. The ẟ34S isotopic signatures in sulphides of the Koperberg Suite (-1.4 to +1.91‰) and the proposed contaminant, the Khurisberg Subgroup (-1.2 to +3.5‰), overlap with the those of the Koperberg Suite below the Khurisberg Subgroup (+0.74‰) and typical mantle-derived magmatic rocks (0 ± iv 2‰). Hence, the sulphur isotope variations are inconclusive as an indicator of possible crustal sulphur assimilation into the intruding mantle magma. However, considering the trace element systematics and the sulphur isotope data, the Koperberg magmas likely attained sulphur saturation at deeper crustal levels. , Thesis (MSc) -- Faculty of Science, Geology, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Marima, Edmore
- Date: 2022-04-06
- Subjects: Sulfur Isotopes , Magmatism South Africa Namaqualand , Sulfides , Koperberg Suite (South Africa) , Copper sulfide , Sulfur Absorption and adsorption
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291117 , vital:56820
- Description: The major economic copper sulphide deposits hosted in the late Mesoproterozoic intrusions of the Koperberg Suite in the O’okiep Copper District immediately overlie sulphur-bearing paragneisses of the Khurisberg Subgroup in an otherwise low-sulphur granitic basement. The dominant sulphide assemblage (chalcopyrite and bornite) hosted in the Koperberg Suite is also atypical of the intermediate solid solution (iss) assemblage (chalcopyrite and pyrrhotite) observed in most Cu-Ni magmatic sulphide deposits. This study presents sulphur isotope and in-situ trace element analysis of sulphides from the Koperberg Suite and the Khurisberg Subgroup with the view of placing constraints on the role of sulphide-bearing supracrustal metasedimentary of the Khurisberg Subgroup as a source of additional sulphur in the genesis of these deposits, and ore-forming (sulphide formation) processes which result in trace element variations registered by sulphides hosted in the Koperberg Suite. The high concentrations (up to 2100 ppm) of monosulphide solid solution (mss)-incompatible trace elements (e.g., Te, Se, Bi, Ag, Pb), and the depletion in Ni and Co (<40 ppm) of sulphides hosted in the Koperberg Suite are instead consistent with the derivation of such sulphides from a Cu-rich sulphide melt which segregated from a Ni-rich sulphide melt prior to magma emplacement in the middle crust, in agreement with one of the petrogenetic models for the Koperberg Suite proposed in the existing literature. The low S/Se ratios ( ̴650-10300) of sulphides hosted in the Koperberg Suite and the high S/Se ratios ( ̴18800-56000) registered by the main sulphide phase (pyrite) in the Khurisberg Subgroup argues against crustal contamination of the Koperberg Suite magmas by the Khurisberg Subgroup. The S/Se and Cu/S ratios of coexisting bornite and chalcopyrite hosted in the Koperberg Suite are positively correlated with the bornite modal abundance in the Koperberg Suite. Such trends are interpreted to be consistent with progressive oxidation of sulphide melt, a process which results in the crystallisation of iss-bornite assemblage and/or replacement of iss with bornite due to the enrichment of Cu and depletion in S of the sulphide melt. The oxidation of sulphide melt is likely to have been effectuated by the fractional crystallisation of mss in a prior sulphide melt segregation event and/or the fractional crystallisation of Fe2+-dominated silicate phases. Fractionation of the Cu-rich melt sulphide melt (segregated from mss) also tends to enrich the residual sulphide melts in Se. Thus, the chalcopyrite-dominated assemblage with S/Se ratios of ̴1300-10200 observed in the less basic rocks in the Koperberg Suite (leucodiorites and leuconorites) is interpreted to have formed from the least evolved sulphide melt, whereas the bornite-dominated assemblage with S/Se ratios of ̴650-5500 observed in the more mafic members of the Koperberg Suite (orthopyroxenites and norites) is interpreted to have formed from the most evolved sulphide melt. The ẟ34S isotopic signatures in sulphides of the Koperberg Suite (-1.4 to +1.91‰) and the proposed contaminant, the Khurisberg Subgroup (-1.2 to +3.5‰), overlap with the those of the Koperberg Suite below the Khurisberg Subgroup (+0.74‰) and typical mantle-derived magmatic rocks (0 ± iv 2‰). Hence, the sulphur isotope variations are inconclusive as an indicator of possible crustal sulphur assimilation into the intruding mantle magma. However, considering the trace element systematics and the sulphur isotope data, the Koperberg magmas likely attained sulphur saturation at deeper crustal levels. , Thesis (MSc) -- Faculty of Science, Geology, 2022
- Full Text:
- Date Issued: 2022-04-06