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
A multispectral and machine learning approach to early stress classification in plants
- Authors: Poole, Louise Carmen
- Date: 2022-04-06
- Subjects: Machine learning , Neural networks (Computer science) , Multispectral imaging , Image processing , Plant stress detection
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232410 , vital:49989
- Description: Crop loss and failure can impact both a country’s economy and food security, often to devastating effects. As such, the importance of successfully detecting plant stresses early in their development is essential to minimize spread and damage to crop production. Identification of the stress and the stress-causing agent is the most critical and challenging step in plant and crop protection. With the development of and increase in ease of access to new equipment and technology in recent years, the use of spectroscopy in the early detection of plant diseases has become notably popular. This thesis narrows down the most suitable multispectral imaging techniques and machine learning algorithms for early stress detection. Datasets were collected of visible images and multispectral images. Dehydration was selected as the plant stress type for the main experiments, and data was collected from six plant species typically used in agriculture. Key contributions of this thesis include multispectral and visible datasets showing plant dehydration as well as a separate preliminary dataset on plant disease. Promising results on dehydration showed statistically significant accuracy improvements in the multispectral imaging compared to visible imaging for early stress detection, with multispectral input obtaining a 92.50% accuracy over visible input’s 77.50% on general plant species. The system was effective at stress detection on known plant species, with multispectral imaging introducing greater improvement to early stress detection than advanced stress detection. Furthermore, strong species discrimination was achieved when exclusively testing either early or advanced dehydration against healthy species. , Thesis (MSc) -- Faculty of Science, Ichthyology & Fisheries Sciences, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Poole, Louise Carmen
- Date: 2022-04-06
- Subjects: Machine learning , Neural networks (Computer science) , Multispectral imaging , Image processing , Plant stress detection
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232410 , vital:49989
- Description: Crop loss and failure can impact both a country’s economy and food security, often to devastating effects. As such, the importance of successfully detecting plant stresses early in their development is essential to minimize spread and damage to crop production. Identification of the stress and the stress-causing agent is the most critical and challenging step in plant and crop protection. With the development of and increase in ease of access to new equipment and technology in recent years, the use of spectroscopy in the early detection of plant diseases has become notably popular. This thesis narrows down the most suitable multispectral imaging techniques and machine learning algorithms for early stress detection. Datasets were collected of visible images and multispectral images. Dehydration was selected as the plant stress type for the main experiments, and data was collected from six plant species typically used in agriculture. Key contributions of this thesis include multispectral and visible datasets showing plant dehydration as well as a separate preliminary dataset on plant disease. Promising results on dehydration showed statistically significant accuracy improvements in the multispectral imaging compared to visible imaging for early stress detection, with multispectral input obtaining a 92.50% accuracy over visible input’s 77.50% on general plant species. The system was effective at stress detection on known plant species, with multispectral imaging introducing greater improvement to early stress detection than advanced stress detection. Furthermore, strong species discrimination was achieved when exclusively testing either early or advanced dehydration against healthy species. , Thesis (MSc) -- Faculty of Science, Ichthyology & Fisheries Sciences, 2022
- Full Text:
- Date Issued: 2022-04-06
Effects of hydraulic fracking fluid on soil microbial composition and diversity
- Authors: Sianyuka, Nicolette
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232366 , vital:49985
- Description: Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Sianyuka, Nicolette
- Date: 2022-04-06
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/232366 , vital:49985
- Description: Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 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
The biology and movement patterns of non-native common carp, cyprinus carpio (l) in Groenvlei, South Africa
- Authors: Mukhari, Dinah Lorraine
- Date: 2022-04-06
- Subjects: Carp South Africa Goukamma Nature Reserve , Introduced fishes South Africa Goukamma Nature Reserve , Carp Behavior South Africa Goukamma Nature Reserve , Carp South Africa Goukamma Nature Reserve Growth , Carp Habitat South Africa Goukamma Nature Reserve , Carp South Africa Goukamma Nature Reserve Reproduction , Habitat conservation South Africa Goukamma Nature Reserve , Aquatic resources conservation South Africa Goukamma Nature Reserve
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291233 , vital:56834
- Description: The common carp, Cyprinus carpio is a highly invasive fish species, first introduced into South Africa in the late nineteen century, and now widely spread throughout the country. In 1991 carp were illegally introduced to Groenvlei, within the Goukamma Nature Reserve in the Western Cape Province. Decreases in water quality and declines in biota have been attributed to the now large numbers of carp. Management measures have commenced to reduce the carp population, however these are not underpinned by science as little is known about the biology and movement patterns of resident carp. The age, growth and maturity of carp within the lake was determined using oxytetracycline hydrochloride marked asteriscus otoliths and macroscopic gonad development staging methods. The results showed that carp in Groenvlei had similar growth characteristics to the invasive populations in North America and Australia; fast growth during the first three to five years and reproductive maturity attained between the ages of two to three years, and are long lived (maximum age of 20 years old). Their growth however differed from the only other study on a South African population. Six acoustically tagged carp were manually tracked in order to report on their movement patterns and habitat use. Carp moved much greater distances in February compared to October and November, and occupied different areas of the lake. In November they were found to aggregate in backwaters which corresponds with their breeding activities. Literature on global carp control shows that whilst eradication of this fish can be achieved in small isolated waters using icthyocides and water drawdowns, in conservation priority areas such as Groenvlei where this is not possible, mechanical removal using multiple gears targeting vulnerable life stages can most efficient at controlling carp. This study identified where and when these methods could be focused to optimise control efforts. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Mukhari, Dinah Lorraine
- Date: 2022-04-06
- Subjects: Carp South Africa Goukamma Nature Reserve , Introduced fishes South Africa Goukamma Nature Reserve , Carp Behavior South Africa Goukamma Nature Reserve , Carp South Africa Goukamma Nature Reserve Growth , Carp Habitat South Africa Goukamma Nature Reserve , Carp South Africa Goukamma Nature Reserve Reproduction , Habitat conservation South Africa Goukamma Nature Reserve , Aquatic resources conservation South Africa Goukamma Nature Reserve
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/291233 , vital:56834
- Description: The common carp, Cyprinus carpio is a highly invasive fish species, first introduced into South Africa in the late nineteen century, and now widely spread throughout the country. In 1991 carp were illegally introduced to Groenvlei, within the Goukamma Nature Reserve in the Western Cape Province. Decreases in water quality and declines in biota have been attributed to the now large numbers of carp. Management measures have commenced to reduce the carp population, however these are not underpinned by science as little is known about the biology and movement patterns of resident carp. The age, growth and maturity of carp within the lake was determined using oxytetracycline hydrochloride marked asteriscus otoliths and macroscopic gonad development staging methods. The results showed that carp in Groenvlei had similar growth characteristics to the invasive populations in North America and Australia; fast growth during the first three to five years and reproductive maturity attained between the ages of two to three years, and are long lived (maximum age of 20 years old). Their growth however differed from the only other study on a South African population. Six acoustically tagged carp were manually tracked in order to report on their movement patterns and habitat use. Carp moved much greater distances in February compared to October and November, and occupied different areas of the lake. In November they were found to aggregate in backwaters which corresponds with their breeding activities. Literature on global carp control shows that whilst eradication of this fish can be achieved in small isolated waters using icthyocides and water drawdowns, in conservation priority areas such as Groenvlei where this is not possible, mechanical removal using multiple gears targeting vulnerable life stages can most efficient at controlling carp. This study identified where and when these methods could be focused to optimise control efforts. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-04-06
An investigation into stakeholder inclusivity and the board’s ability to create competitive advantage at South Africa’s “big five” retail banks
- Authors: Wolhuter, Darren Wilfred
- Date: 2022-04-06
- Subjects: Stakeholder management South Africa , Strategic planning South Africa , Banks and banking South Africa , Corporate governance South Africa , Competition , Resource-based theory
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284548 , vital:56073
- Description: Stakeholder theory has long put forth the concept that managerial attention must be given to all stakeholders towards the realisation of value creation opportunities. Through the process of stakeholder engagement, and through the adoption of stakeholder inclusivity principles, an organisation can position itself to reap the benefits of understanding the legitimate needs and interests of all its stakeholders by seeking to satisfy all its stakeholders in turn. This study analysed the integrated reports of five retail banks, whose main base of operations were in South Africa, to assess the board’s ability to create value for its stakeholders through adopting a stakeholder inclusive approach to corporate governance as advocated for by the King Code on Corporate Governance in South Africa – King IV™. This assessment was done through an examination of a selection of outcomes relevant to the banking industry and related to each of the six capitals that form part of the value creation process as indicated for in the Integrated Reporting Framework (IIRC, 2013): 1) Financial Capital, 2) Manufactured Capital; 3) Intellectual Capital; 4) Human Capital; 5) Social and Relationship Capital, and; 6) Natural Capital. The results obtained, over a three-year period – 2018 to 2020, revealed that while the directors had a firm understanding of who their material stakeholders were, they struggled to create value that catered to all their stakeholders collectively. In addition, the directors were also unable to create sustainable value over the assessment period. As a result of this, most banks, with the exception of one, were unable to realise the value creation opportunities that could have led to a potential source of competitive advantage. The study concludes that while no observable sustainable competitive advantage was evident over the period of assessment, the concept of stakeholder inclusivity is an important corporate governance principle that drives value creation and, as such, warrants more attention from the director’s point of view. This research is intended to contribute to the growing knowledge on the importance of stakeholder inclusivity in corporate governance execution. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Wolhuter, Darren Wilfred
- Date: 2022-04-06
- Subjects: Stakeholder management South Africa , Strategic planning South Africa , Banks and banking South Africa , Corporate governance South Africa , Competition , Resource-based theory
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284548 , vital:56073
- Description: Stakeholder theory has long put forth the concept that managerial attention must be given to all stakeholders towards the realisation of value creation opportunities. Through the process of stakeholder engagement, and through the adoption of stakeholder inclusivity principles, an organisation can position itself to reap the benefits of understanding the legitimate needs and interests of all its stakeholders by seeking to satisfy all its stakeholders in turn. This study analysed the integrated reports of five retail banks, whose main base of operations were in South Africa, to assess the board’s ability to create value for its stakeholders through adopting a stakeholder inclusive approach to corporate governance as advocated for by the King Code on Corporate Governance in South Africa – King IV™. This assessment was done through an examination of a selection of outcomes relevant to the banking industry and related to each of the six capitals that form part of the value creation process as indicated for in the Integrated Reporting Framework (IIRC, 2013): 1) Financial Capital, 2) Manufactured Capital; 3) Intellectual Capital; 4) Human Capital; 5) Social and Relationship Capital, and; 6) Natural Capital. The results obtained, over a three-year period – 2018 to 2020, revealed that while the directors had a firm understanding of who their material stakeholders were, they struggled to create value that catered to all their stakeholders collectively. In addition, the directors were also unable to create sustainable value over the assessment period. As a result of this, most banks, with the exception of one, were unable to realise the value creation opportunities that could have led to a potential source of competitive advantage. The study concludes that while no observable sustainable competitive advantage was evident over the period of assessment, the concept of stakeholder inclusivity is an important corporate governance principle that drives value creation and, as such, warrants more attention from the director’s point of view. This research is intended to contribute to the growing knowledge on the importance of stakeholder inclusivity in corporate governance execution. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-04-06
Protecting the right to identity against catfishing
- Authors: Ndyulo, Lisa Neliswa Latima
- Date: 2022-04-06
- Subjects: Catfishing South Africa , False personation Law and legislation South Africa , Torts South Africa , Mass media and publicity South Africa , Social media Law and legislation South Africa , Identity theft Law and legislation South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290767 , vital:56782
- Description: Catfishing is a form of impersonation occurring on social media that interferes with a person’s right to identity. It involves creating a fake profile online using another person’s images. The facets of the right to identity are image, name, and likeness, among others. Catfishing affects a person’s right to identity and human dignity. Hence, the thesis aims to determine whether the right to identity adequately protects individuals against catfishing. This thesis is a desktop analysis considering the South African legal framework related to the right to identity, including the common law, the Constitution of the Republic of South Africa, 1996, and legislation. The thesis is also a comparative analysis assessing the adequacy of addressing catfishing through the right to identity. The study evaluates the right to identity’s adequacy by juxtaposing the South African legal framework with California and Oklahoma’s common law and statutory interventions. The study reveals that the right to identity protects South African social networking website users against catfishing. Like the common law right of privacy in California and Oklahoma, a person infringes the right to identity when they use another person’s identity facets to portray them in a false light, and like the statutory right of publicity in California and Oklahoma, a person infringes identity when they appropriate facets of another person’s identity for commercial gain. The infringement of the right to identity entitles a person to legal remedies, including a claim for damages, among other things. The thesis also considers principles of conflict of laws to determine the operative law in an instance where a victim resides in South Africa and the perpetrator resides in the US, or vice versa. The study recommends that developing the common law to recognise that identity can be infringed by mere appropriation not linked to a commercial purpose would be beneficial for addressing catfishing adequately in South Africa. Legal development contributes to the constitutional imperative to align the common law with society’s shifting needs and address novel legal issues, such as catfishing. , Thesis (LLM) -- Faculty of Law, Law, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Ndyulo, Lisa Neliswa Latima
- Date: 2022-04-06
- Subjects: Catfishing South Africa , False personation Law and legislation South Africa , Torts South Africa , Mass media and publicity South Africa , Social media Law and legislation South Africa , Identity theft Law and legislation South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290767 , vital:56782
- Description: Catfishing is a form of impersonation occurring on social media that interferes with a person’s right to identity. It involves creating a fake profile online using another person’s images. The facets of the right to identity are image, name, and likeness, among others. Catfishing affects a person’s right to identity and human dignity. Hence, the thesis aims to determine whether the right to identity adequately protects individuals against catfishing. This thesis is a desktop analysis considering the South African legal framework related to the right to identity, including the common law, the Constitution of the Republic of South Africa, 1996, and legislation. The thesis is also a comparative analysis assessing the adequacy of addressing catfishing through the right to identity. The study evaluates the right to identity’s adequacy by juxtaposing the South African legal framework with California and Oklahoma’s common law and statutory interventions. The study reveals that the right to identity protects South African social networking website users against catfishing. Like the common law right of privacy in California and Oklahoma, a person infringes the right to identity when they use another person’s identity facets to portray them in a false light, and like the statutory right of publicity in California and Oklahoma, a person infringes identity when they appropriate facets of another person’s identity for commercial gain. The infringement of the right to identity entitles a person to legal remedies, including a claim for damages, among other things. The thesis also considers principles of conflict of laws to determine the operative law in an instance where a victim resides in South Africa and the perpetrator resides in the US, or vice versa. The study recommends that developing the common law to recognise that identity can be infringed by mere appropriation not linked to a commercial purpose would be beneficial for addressing catfishing adequately in South Africa. Legal development contributes to the constitutional imperative to align the common law with society’s shifting needs and address novel legal issues, such as catfishing. , Thesis (LLM) -- Faculty of Law, Law, 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
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
The quality of higher education and its influence on graduate employability and employer perception
- Authors: Mqingwana, Siviwe Nokulinda
- Date: 2022-04-06
- Subjects: Employability , Career education , Education, Higher Aims and objectives , College graduates Employment , Universities and colleges Ratings and rankings , Labor supply Effect of education on , College graduates Vocational guidance
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284526 , vital:56071
- Description: This study examined the quality of higher education and its influence on graduate employability and employer perception. Through determining the factors influencing graduates’ employment by employers and also the elements that induce employers in employing graduates, this was achieved. This research is rooted in a positivist perspective determining the relationship between graduate employability and a universities’ status. The main goal of this research was to examine to what extent employers are influenced by a higher education institution's perceived reputation when employing graduates. The linear regression model was used to predict the relationship between graduate employability (dependent variable) and the perceived reputation of the university by employers and citations of the university. This was achieved using quantitative methods. The quantitative database that this research relied on is Quacquarelli Symonds (QS) world university ranking. This research made use of descriptive data analysis as well as linear regression. The data set analysis showed citations of the institution had a significant negative relationship with the rate of employability (although this was a relatively weak relationship). The reputation of the institution and the number of international students enrolled do not affect the rate of employability. The analysed data set also showed that the number of citations of a university had a significant impact on the rate of employability at the 10% significance level. As such, higher education institutions need to consider including current market demand into their offerings to improve their graduate’s employability. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Mqingwana, Siviwe Nokulinda
- Date: 2022-04-06
- Subjects: Employability , Career education , Education, Higher Aims and objectives , College graduates Employment , Universities and colleges Ratings and rankings , Labor supply Effect of education on , College graduates Vocational guidance
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284526 , vital:56071
- Description: This study examined the quality of higher education and its influence on graduate employability and employer perception. Through determining the factors influencing graduates’ employment by employers and also the elements that induce employers in employing graduates, this was achieved. This research is rooted in a positivist perspective determining the relationship between graduate employability and a universities’ status. The main goal of this research was to examine to what extent employers are influenced by a higher education institution's perceived reputation when employing graduates. The linear regression model was used to predict the relationship between graduate employability (dependent variable) and the perceived reputation of the university by employers and citations of the university. This was achieved using quantitative methods. The quantitative database that this research relied on is Quacquarelli Symonds (QS) world university ranking. This research made use of descriptive data analysis as well as linear regression. The data set analysis showed citations of the institution had a significant negative relationship with the rate of employability (although this was a relatively weak relationship). The reputation of the institution and the number of international students enrolled do not affect the rate of employability. The analysed data set also showed that the number of citations of a university had a significant impact on the rate of employability at the 10% significance level. As such, higher education institutions need to consider including current market demand into their offerings to improve their graduate’s employability. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-04-06
Motives and barriers to the implementation of renewable energy sources in South African tertiary institutions
- Authors: Sibindi, Siyangiso
- Date: 2022-04-06
- Subjects: Renewable energy sources South Africa , Education, Higher South Africa , Education, Higher Environmental aspects South Africa , Environmental responsibility South Africa , Climate change mitigation South Africa , Sustainable development South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284537 , vital:56072
- Description: Organisations face major challenges to address the exploitation of non-renewable resources and consider management considerations for dealing with climate change. Organisations have been pushed to play a part in their carbon footprints and in curbing climate change. Among these organisations are tertiary institutions that can greatly impact environmental sustainability and address carbon dioxide emissions by embarking on renewable energy technologies. Tertiary institutions play a major role in society by the provision of skilled labour and personnel that are equipped to deal with a range of advancements and challenges. The sustainability of these tertiary institutions has thus been called into question due to the impact they can bring to societies. This research thus aims to identify the motives and barriers to renewable energy adoption in tertiary education institutions. To do this, a literature review was conducted to identify possible motives and barriers to renewable energy adoption. These were then compiled into a questionnaire that was sent to respondents of three different institutions. Respondents were then requested to give feedback on each of the motives and barriers. The respondents were also asked general questions found in literature that addressed the adoption of renewable energy technologies in tertiary institutions. The data was collected using the designed questionnaires. The respondents were able to articulate their perceived barriers and motives to the implementation of renewable energy technologies in tertiary institutions. Data analysis was done using thematic analysis. The results showed that the barriers in the implementation of renewable energy technologies in tertiary institutions were: ‘Cost to Install’, ‘Transition Process’ and ‘Government Policies’. The motives on why educational institutions need to embark on renewable energy projects were found to be ‘Energy Independence’, ‘Cleaner Source of Energy’ and ‘Reduction in Carbon Emissions’. The cost of renewable energy technologies, the process of moving from the Eskom grid, and renewable energy policies that are ambiguous were some factors that were highlighted by respondents on why it is challenging to adopt renewable energies in tertiary institutions. On the other hand, the effects of load shedding currently being experienced in the country and the migration to cleaner sources of energy that cause less harm to the environment, are some of the drivers noted by respondents on why tertiary institutions need to embark on renewable energy technologies. More emphasis needs to be put by stakeholders on tertiary institutions to migrate to cleaner sources of energy, and policies need to be put in place in order to promote institutions to adopt these types of energies. Governments and other role-players need to be visible at all times in addressing energy challenges in tertiary institutions in the wake of the recent load-shedding concerns that have been crippling South Africa. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Sibindi, Siyangiso
- Date: 2022-04-06
- Subjects: Renewable energy sources South Africa , Education, Higher South Africa , Education, Higher Environmental aspects South Africa , Environmental responsibility South Africa , Climate change mitigation South Africa , Sustainable development South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284537 , vital:56072
- Description: Organisations face major challenges to address the exploitation of non-renewable resources and consider management considerations for dealing with climate change. Organisations have been pushed to play a part in their carbon footprints and in curbing climate change. Among these organisations are tertiary institutions that can greatly impact environmental sustainability and address carbon dioxide emissions by embarking on renewable energy technologies. Tertiary institutions play a major role in society by the provision of skilled labour and personnel that are equipped to deal with a range of advancements and challenges. The sustainability of these tertiary institutions has thus been called into question due to the impact they can bring to societies. This research thus aims to identify the motives and barriers to renewable energy adoption in tertiary education institutions. To do this, a literature review was conducted to identify possible motives and barriers to renewable energy adoption. These were then compiled into a questionnaire that was sent to respondents of three different institutions. Respondents were then requested to give feedback on each of the motives and barriers. The respondents were also asked general questions found in literature that addressed the adoption of renewable energy technologies in tertiary institutions. The data was collected using the designed questionnaires. The respondents were able to articulate their perceived barriers and motives to the implementation of renewable energy technologies in tertiary institutions. Data analysis was done using thematic analysis. The results showed that the barriers in the implementation of renewable energy technologies in tertiary institutions were: ‘Cost to Install’, ‘Transition Process’ and ‘Government Policies’. The motives on why educational institutions need to embark on renewable energy projects were found to be ‘Energy Independence’, ‘Cleaner Source of Energy’ and ‘Reduction in Carbon Emissions’. The cost of renewable energy technologies, the process of moving from the Eskom grid, and renewable energy policies that are ambiguous were some factors that were highlighted by respondents on why it is challenging to adopt renewable energies in tertiary institutions. On the other hand, the effects of load shedding currently being experienced in the country and the migration to cleaner sources of energy that cause less harm to the environment, are some of the drivers noted by respondents on why tertiary institutions need to embark on renewable energy technologies. More emphasis needs to be put by stakeholders on tertiary institutions to migrate to cleaner sources of energy, and policies need to be put in place in order to promote institutions to adopt these types of energies. Governments and other role-players need to be visible at all times in addressing energy challenges in tertiary institutions in the wake of the recent load-shedding concerns that have been crippling South Africa. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2022
- Full Text:
- Date Issued: 2022-04-06
Exchange rate volatility and the returns on diversified South African investment portfolios
- Authors: Mulamu, Murendeni
- Date: 2022-04-06
- Subjects: Foreign exchange rates South Africa , Rate of return , Investments , GARCH model , Regression analysis , Autoregressive distributed lag (ARDL) model
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284581 , vital:56076
- Description: Globalisation has made it much easier to invest in foreign countries. This creates endless options accessible to investors, including exploiting opportunities for investment in international economies. Although foreign investment portfolio diversification provides significant opportunities for financial returns, exchange rate volatility may play a prominent role when investing in foreign markets. Since the introduction of a floating exchange rate system, together with the inflation-targeting monetary policy framework in South Africa, there has been significant volatility in the exchange rate, far more than during the previous dispensations. This, however, creates a strong need to consider how the unpredictable nature of the exchange rate affects these investments. The purpose of this study is to analyse the effect of exchange rate volatility on the returns on diversified South African investment portfolios. This research examined whether there is a homogenous relationship between South African (domestic) portfolios and the internationally diversified portfolios. In addition, the study investigated the long-run relationship between the exchange rate volatility and both domestic portfolios and the internationally diversified portfolios for the period 2007-2019. To achieve these goals, a panel ARDL model was employed. This study found that exchange rate volatility does not account for a significant portion of returns on investment portfolios fluctuations. Moreover, the relationship is not homogenous because returns on domestic investment portfolios react positively to the exchange rate volatility, whereas returns international investment portfolios respond negatively/positively to the exchange rate volatility depending on whether the relationship is short or long run. This study will contribute to the existing literature, and it is important for investors intending to diversify their investment portfolios both domestically and internationally using different mutual funds in South Africa. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Mulamu, Murendeni
- Date: 2022-04-06
- Subjects: Foreign exchange rates South Africa , Rate of return , Investments , GARCH model , Regression analysis , Autoregressive distributed lag (ARDL) model
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/284581 , vital:56076
- Description: Globalisation has made it much easier to invest in foreign countries. This creates endless options accessible to investors, including exploiting opportunities for investment in international economies. Although foreign investment portfolio diversification provides significant opportunities for financial returns, exchange rate volatility may play a prominent role when investing in foreign markets. Since the introduction of a floating exchange rate system, together with the inflation-targeting monetary policy framework in South Africa, there has been significant volatility in the exchange rate, far more than during the previous dispensations. This, however, creates a strong need to consider how the unpredictable nature of the exchange rate affects these investments. The purpose of this study is to analyse the effect of exchange rate volatility on the returns on diversified South African investment portfolios. This research examined whether there is a homogenous relationship between South African (domestic) portfolios and the internationally diversified portfolios. In addition, the study investigated the long-run relationship between the exchange rate volatility and both domestic portfolios and the internationally diversified portfolios for the period 2007-2019. To achieve these goals, a panel ARDL model was employed. This study found that exchange rate volatility does not account for a significant portion of returns on investment portfolios fluctuations. Moreover, the relationship is not homogenous because returns on domestic investment portfolios react positively to the exchange rate volatility, whereas returns international investment portfolios respond negatively/positively to the exchange rate volatility depending on whether the relationship is short or long run. This study will contribute to the existing literature, and it is important for investors intending to diversify their investment portfolios both domestically and internationally using different mutual funds in South Africa. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2022
- Full Text:
- Date Issued: 2022-04-06
A retrospective study of antimicrobial prescribing practices in paediatric patients at the Mahalapye District Hospital, Central Botswana
- Authors: Nyawera, Angella
- Date: 2022-04-06
- Subjects: Anti-infective agents Botswana Mahalapye , Drug resistance , Pediatrics Botswana Mahalapye , Pediatrics Formulae, receipts, prescriptions , Drugs Prescribing Moral and ethical aspects
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290682 , vital:56774
- Description: Background: The development of antimicrobial resistance (AMR) has been linked to the increased and irrational use of antimicrobial medicines. The aim of this study was to investigate the antimicrobial prescribing practices in the paediatric medical ward at Mahalapye District Hospital (MDH) in Botswana and to determine whether antimicrobial stewardship (AMS) measures were being implemented at the hospital. Methods A cross-sectional, descriptive, mixed methods, observational approach was taken in this study. The study site was the paediatric medical ward (PMW) at MDH. Information about the antimicrobials prescribed for paediatric patients from January 2018 to December 2018 was collected from patients’ information files and compared to national antimicrobial prescribing guidelines to determine prescribers’ adherence. Qualitative semi-structured interviews were conducted with members of staff at MDH to determine whether antimicrobial stewardship (AMS) measures were adopted at the hospital. Results A total of 278 patients were included in this study, 12 of these were admitted twice during the study period. In total 290 admissions were analysed, with 659 antimicrobial medicines prescribed. The most common diagnoses were pneumonia (36.9%), acute gastroenteritis (20.7%), upper respiratory tract infections (3.4%), and bronchiolitis (3.1%). The most prescribed antimicrobials were ampicillin (21.4%), gentamicin (21.2%), and cefotaxime (8.3%). Adherence to guidelines was relatively good, with 82.7% of antimicrobials prescribed for the patients in the study having been prescribed in compliance with the national prescribing guidelines. The semi-structured interviews highlighted the fact that staff knew about AMS and AMR in general, however awareness of an AMS committee at MDH varied. The AMS committee was a multidisciplinary committee, which was a subcommittee of the Drugs and Therapeutics Committee (DTC). Discussion and Conclusion The results suggest that adherence to prescribing guidelines was relatively high compared to other paediatric antimicrobial utilisation studies in African countries. Prescribing of antimicrobial medicines was consistent with other African countries. The long period of time that it takes for microbiological test results to become available means that most prescribers rely on empirical prescribing. The antimicrobial committee is a multidisciplinary committee with defined roles for its members, consistent with international guidelines for implementing an AMS committee at a hospital. , Thesis (MPharm) -- Faculty of Pharmacy, Pharmacy, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Nyawera, Angella
- Date: 2022-04-06
- Subjects: Anti-infective agents Botswana Mahalapye , Drug resistance , Pediatrics Botswana Mahalapye , Pediatrics Formulae, receipts, prescriptions , Drugs Prescribing Moral and ethical aspects
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290682 , vital:56774
- Description: Background: The development of antimicrobial resistance (AMR) has been linked to the increased and irrational use of antimicrobial medicines. The aim of this study was to investigate the antimicrobial prescribing practices in the paediatric medical ward at Mahalapye District Hospital (MDH) in Botswana and to determine whether antimicrobial stewardship (AMS) measures were being implemented at the hospital. Methods A cross-sectional, descriptive, mixed methods, observational approach was taken in this study. The study site was the paediatric medical ward (PMW) at MDH. Information about the antimicrobials prescribed for paediatric patients from January 2018 to December 2018 was collected from patients’ information files and compared to national antimicrobial prescribing guidelines to determine prescribers’ adherence. Qualitative semi-structured interviews were conducted with members of staff at MDH to determine whether antimicrobial stewardship (AMS) measures were adopted at the hospital. Results A total of 278 patients were included in this study, 12 of these were admitted twice during the study period. In total 290 admissions were analysed, with 659 antimicrobial medicines prescribed. The most common diagnoses were pneumonia (36.9%), acute gastroenteritis (20.7%), upper respiratory tract infections (3.4%), and bronchiolitis (3.1%). The most prescribed antimicrobials were ampicillin (21.4%), gentamicin (21.2%), and cefotaxime (8.3%). Adherence to guidelines was relatively good, with 82.7% of antimicrobials prescribed for the patients in the study having been prescribed in compliance with the national prescribing guidelines. The semi-structured interviews highlighted the fact that staff knew about AMS and AMR in general, however awareness of an AMS committee at MDH varied. The AMS committee was a multidisciplinary committee, which was a subcommittee of the Drugs and Therapeutics Committee (DTC). Discussion and Conclusion The results suggest that adherence to prescribing guidelines was relatively high compared to other paediatric antimicrobial utilisation studies in African countries. Prescribing of antimicrobial medicines was consistent with other African countries. The long period of time that it takes for microbiological test results to become available means that most prescribers rely on empirical prescribing. The antimicrobial committee is a multidisciplinary committee with defined roles for its members, consistent with international guidelines for implementing an AMS committee at a hospital. , Thesis (MPharm) -- 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
Cloning, expression, partial characterisation and application of a recombinant GH10 xylanase, XT6, from Geobacillus stearothermophilus T6 as an additive to chicken feeds
- Authors: Sithole, Tariro
- Date: 2022-04-06
- Subjects: Chicken feed industry , Chickens Feeding and feeds , Bacillus (Bacteria) , Xylanases , Polysaccharides , Geobacillus stearothermophilus
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/292693 , vital:57007
- Description: Monogastric animal farming has largely been sustained by feeding animals with grain feedstocks containing non-starch polysaccharides (NSPs) and anti-nutritive factors, which cause adverse effects, such as increased digesta viscosity and entrapment of nutrients, which leads to the inaccessibility of nutrients. These effects have been linked to a reduction in nutrient digestion and absorption, which results in a decreased feed conversion ratio, energy metabolism and animal growth. Monogastric animals do not produce enzymes that can hydrolyse these NSPs. The application of exogenous enzymes as supplements to animal feeds has been implemented to reduce viscosity and increase nutrient absorption in poultry and pigs over the past few decades. The aim of this study was to clone, express, partially characterise and apply a glycoside hydrolase (GH) family 10 xylanase (XT6), derived from Geobacillus stearothermophilus T6, as an additive to locally produced chicken feeds. The xt6 gene (1,236 bp) was subcloned and expressed in Escherichia coli DH5α and BL21(DE3) cells, respectively. Upon expression, XT6 had a molecular weight of 42 kDa and was partially purified by Ni-NTA chromatography and ultrafiltration. The purification step resulted in a yield of 66.7% with a 16.8-fold increase in purification. XT6 exhibited maximal activity when incubated at a pH and temperature of pH 6.0 and 70°C, respectively, with a high thermostability over a broad range of pH (2–9) and temperature (30–90 °C). The specific activities of XT6 on extracted soluble and insoluble wheat flour arabinoxylans were 110.9 U/mg and 63.98 U/mg, respectively. Kinetic data showed that XT6 displayed a higher catalytic activity and affinity (Vmax = 231.60 μmol/min/mg and KM = 2.759 mg/ml) for soluble wheat arabinoxylan, compared to insoluble wheat arabinoxylan (Vmax = 99.02 μmol/min/mg and KM = 5.058 mg/ml). High-performance liquid chromatography (HPLC) analysis showed that the enzyme hydrolysed wheat flour, arabinoxylan and chicken feeds, producing a range of xylooligosaccharides (XOS), with xylotetraose and xylopentaose being the predominant XOS species. Hydrolysis of both soluble and insoluble wheat flour arabinoxylans by XT6 led to a significant reduction in substrate viscosity. The effects of simulated gastrointestinal fluid contents, such as proteases, bile salts and mucins, on XT6 stability were also studied. Exposure of XT6 to pepsin did not significantly reduce its activity; however, the inhibitory effect of trypsin and mucin on XT6 was much greater. The presence of gut-derived bile salts had no iii | P a g e significant effect on XT6 activity. Finally, it was shown that the XOS produced from the hydrolysis of chicken feeds (starter and grower feeds) by XT6 significantly enhanced the growth of the probiotic bacteria B. subtilis, while there was no significant improvement in the growth of S. thermophilus and L. bulgaricus. In conclusion, the recombinantly produced XT6 demonstrated efficient hydrolysis of starter and grower feeds, and produced XOS that showed prebiotic activity on selected probiotic bacteria. In addition, the pH, temperature and simulated gastric juice content stability of XT6 renders it an attractive candidate as an additive for chicken feeds. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Sithole, Tariro
- Date: 2022-04-06
- Subjects: Chicken feed industry , Chickens Feeding and feeds , Bacillus (Bacteria) , Xylanases , Polysaccharides , Geobacillus stearothermophilus
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/292693 , vital:57007
- Description: Monogastric animal farming has largely been sustained by feeding animals with grain feedstocks containing non-starch polysaccharides (NSPs) and anti-nutritive factors, which cause adverse effects, such as increased digesta viscosity and entrapment of nutrients, which leads to the inaccessibility of nutrients. These effects have been linked to a reduction in nutrient digestion and absorption, which results in a decreased feed conversion ratio, energy metabolism and animal growth. Monogastric animals do not produce enzymes that can hydrolyse these NSPs. The application of exogenous enzymes as supplements to animal feeds has been implemented to reduce viscosity and increase nutrient absorption in poultry and pigs over the past few decades. The aim of this study was to clone, express, partially characterise and apply a glycoside hydrolase (GH) family 10 xylanase (XT6), derived from Geobacillus stearothermophilus T6, as an additive to locally produced chicken feeds. The xt6 gene (1,236 bp) was subcloned and expressed in Escherichia coli DH5α and BL21(DE3) cells, respectively. Upon expression, XT6 had a molecular weight of 42 kDa and was partially purified by Ni-NTA chromatography and ultrafiltration. The purification step resulted in a yield of 66.7% with a 16.8-fold increase in purification. XT6 exhibited maximal activity when incubated at a pH and temperature of pH 6.0 and 70°C, respectively, with a high thermostability over a broad range of pH (2–9) and temperature (30–90 °C). The specific activities of XT6 on extracted soluble and insoluble wheat flour arabinoxylans were 110.9 U/mg and 63.98 U/mg, respectively. Kinetic data showed that XT6 displayed a higher catalytic activity and affinity (Vmax = 231.60 μmol/min/mg and KM = 2.759 mg/ml) for soluble wheat arabinoxylan, compared to insoluble wheat arabinoxylan (Vmax = 99.02 μmol/min/mg and KM = 5.058 mg/ml). High-performance liquid chromatography (HPLC) analysis showed that the enzyme hydrolysed wheat flour, arabinoxylan and chicken feeds, producing a range of xylooligosaccharides (XOS), with xylotetraose and xylopentaose being the predominant XOS species. Hydrolysis of both soluble and insoluble wheat flour arabinoxylans by XT6 led to a significant reduction in substrate viscosity. The effects of simulated gastrointestinal fluid contents, such as proteases, bile salts and mucins, on XT6 stability were also studied. Exposure of XT6 to pepsin did not significantly reduce its activity; however, the inhibitory effect of trypsin and mucin on XT6 was much greater. The presence of gut-derived bile salts had no iii | P a g e significant effect on XT6 activity. Finally, it was shown that the XOS produced from the hydrolysis of chicken feeds (starter and grower feeds) by XT6 significantly enhanced the growth of the probiotic bacteria B. subtilis, while there was no significant improvement in the growth of S. thermophilus and L. bulgaricus. In conclusion, the recombinantly produced XT6 demonstrated efficient hydrolysis of starter and grower feeds, and produced XOS that showed prebiotic activity on selected probiotic bacteria. In addition, the pH, temperature and simulated gastric juice content stability of XT6 renders it an attractive candidate as an additive for chicken feeds. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-04-06
A framework for guiding the interdisciplinary design of mHealth intervention apps for physical activity behaviour change
- Authors: Thomson, Callie Deborah
- Date: 2022-04-06
- Subjects: Wireless communication systems in medical care , Exercise Health aspects , Behavior modification , Mobile apps , Medical care Technological innovations , Medical informatics , Health promotion Technological innovations , Application software Development , Design Science Research (DSR)
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/232193 , vital:49970 , DOI http://doi.org/10.21504/10962/232193
- Description: The global pandemic of noncommunicable diseases and its associated premature mortality rates and socioeconomic burden have led to increasingly intensified efforts towards designing and delivering health promotion interventions aimed at addressing the leading modifiable health risk behaviours, such as physical inactivity. Developing physical activity behaviour change interventions that target individuals at the dual intra-interpersonal socioecological levels of health promotion has become a key objective worldwide. Digital and mobile technology is revolutionising the ways in which health behaviour change interventions are delivered to individuals across the world, with mobile health applications (mHealth apps) increasingly recognised as a powerful means of promoting physical activity behaviour change. However, with the growth and opportunities of mHealth apps, come several design challenges. Key design challenges concern the integration of theory, the incorporation of evidence-based behaviour change techniques, the application of persuasive systems design principles, and the importance of multi- and interdisciplinary collaborative design, development and evaluation approaches. These key challenges influence the output product design and effectiveness of mHealth physical activity behaviour change intervention apps. There exists a paucity of approaches for guiding and supporting the multi- and interdisciplinary collaborative design, development and evaluation of mHealth physical activity behaviour change intervention apps. To address this gap, this research study proposes an Interdisciplinary mHealth App Design Framework, framed by a novel boundary object view. This view considers the diverse communities of practice, boundary objects and supporting artefacts, process activities, and knowledge sharing practices necessary and relevant to the design of effective mHealth physical activity behaviour change intervention apps. The framework’s development is guided by a Design Science Research (DSR) approach. Its core components are based on the findings of a critical theoretical analysis of twenty existing multi- and interdisciplinary digital health development approaches. Once developed, the framework is evaluated using a qualitative DSR linguistic interpretivist approach, with semi-structured interviews as the research instrument. The thematic analysis findings from interviews with thirty-one international academic researchers and industry practitioners informs the iterative modification and revision of an enhanced Interdisciplinary mHealth App Design Framework, constituting the main DSR artefact contribution of the research study. In addition, four theoretical contributions are made to the mHealth intervention app design body of knowledge, and a practical contribution is made through the provision of guideline recommendations for academics and industry practitioners. Methodological contributions are also made in terms of applying DSR, adopting a hybrid cognitive reasoning strategy, and employing a qualitative linguistic interpretivist approach to evaluation within a DSR project. , Thesis (PhD) -- Faculty of Commerce, Information Systems, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Thomson, Callie Deborah
- Date: 2022-04-06
- Subjects: Wireless communication systems in medical care , Exercise Health aspects , Behavior modification , Mobile apps , Medical care Technological innovations , Medical informatics , Health promotion Technological innovations , Application software Development , Design Science Research (DSR)
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/232193 , vital:49970 , DOI http://doi.org/10.21504/10962/232193
- Description: The global pandemic of noncommunicable diseases and its associated premature mortality rates and socioeconomic burden have led to increasingly intensified efforts towards designing and delivering health promotion interventions aimed at addressing the leading modifiable health risk behaviours, such as physical inactivity. Developing physical activity behaviour change interventions that target individuals at the dual intra-interpersonal socioecological levels of health promotion has become a key objective worldwide. Digital and mobile technology is revolutionising the ways in which health behaviour change interventions are delivered to individuals across the world, with mobile health applications (mHealth apps) increasingly recognised as a powerful means of promoting physical activity behaviour change. However, with the growth and opportunities of mHealth apps, come several design challenges. Key design challenges concern the integration of theory, the incorporation of evidence-based behaviour change techniques, the application of persuasive systems design principles, and the importance of multi- and interdisciplinary collaborative design, development and evaluation approaches. These key challenges influence the output product design and effectiveness of mHealth physical activity behaviour change intervention apps. There exists a paucity of approaches for guiding and supporting the multi- and interdisciplinary collaborative design, development and evaluation of mHealth physical activity behaviour change intervention apps. To address this gap, this research study proposes an Interdisciplinary mHealth App Design Framework, framed by a novel boundary object view. This view considers the diverse communities of practice, boundary objects and supporting artefacts, process activities, and knowledge sharing practices necessary and relevant to the design of effective mHealth physical activity behaviour change intervention apps. The framework’s development is guided by a Design Science Research (DSR) approach. Its core components are based on the findings of a critical theoretical analysis of twenty existing multi- and interdisciplinary digital health development approaches. Once developed, the framework is evaluated using a qualitative DSR linguistic interpretivist approach, with semi-structured interviews as the research instrument. The thematic analysis findings from interviews with thirty-one international academic researchers and industry practitioners informs the iterative modification and revision of an enhanced Interdisciplinary mHealth App Design Framework, constituting the main DSR artefact contribution of the research study. In addition, four theoretical contributions are made to the mHealth intervention app design body of knowledge, and a practical contribution is made through the provision of guideline recommendations for academics and industry practitioners. Methodological contributions are also made in terms of applying DSR, adopting a hybrid cognitive reasoning strategy, and employing a qualitative linguistic interpretivist approach to evaluation within a DSR project. , Thesis (PhD) -- Faculty of Commerce, Information Systems, 2022
- Full Text:
- Date Issued: 2022-04-06
The diversity and dry season habitat associations of fish communities in the Kabompo River Basin, Upper Zambezi, Zambia
- Authors: Rennie, Craig Lawrence
- Date: 2022-04-06
- Subjects: Biodiversity Zambia Kabompo District , Ecology Zambia Kabompo District , Fish communities Zambia Kabompo District , Fishes Ecology Zambia Kabompo District , Freshwater habitats Zambia Kabompo District , Fishes Effect of human beings on Zambia Kabompo District , Fishes Climatic factors Zambia Kabompo District , Mesohabitat
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232261 , vital:49976
- Description: The Zambezian headwaters contain diverse fish communities which support thriving fisheries. This region and its fishes are under pressure from multiple anthropogenic threats, including overexploitation and large-scale developments with potential knock-on effects for the riparian communities. Previous studies have focused on known fisheries areas and the mainstem Zambezi River, neglecting large tributaries such as the Kabompo River. Consequently, little literature is available on the diversity and ecology of the fishes that inhabit these large tributaries, hindering the effective management and protection of biodiversity. This study aimed to fill the current knowledge gaps in the diversity and habitat associations of fish communities in the Upper Zambezi, using the Kabompo River as a case study. The first objective was to provide an updated checklist of the fishes of the Kabompo River basin using a compilation of historical data and field surveys. This study detailed the occurrence and distribution of 83 fish species within the Kabompo River basin. All these species have been recorded in the Upper Zambezi, with some of their ranges extending into the Middle (29 species) and Lower Zambezi (23 species) while others have more restricted distributions. The most diverse families were the Cyprinidae (26 species) and the Cichlidae (15 species). A number of potential undescribed species, whose taxonomic distinctiveness need further investigation were also collected. Taxonomic conflicts are also highlighted for some of the taxa that were previously considered to have broad geographic ranges or disjunct distributions. Consistent with findings from other studies within the region, the current taxonomy underestimates the diversity of fishes in the Kabompo River and Upper Zambezi. The second objective was to assess the habitat use of small-bodied fish communities during the low-flow period in 2019. Reconnaissance trips identified dominant mesohabitats along the middle Kabompo River around Jivundu. A total of 139 mesohabitats were sampled across the five dominant mesohabitats identified; Phragmites mauritianus, wood, rock, Vallisneria aethiopica and bare substrate. Catch per unit effort, species richness, Shannon diversity and Pielou’s evenness differed significantly between these mesohabitats. Twenty-six species showed significant associations (p < 0.05) with a specific mesohabitat type or environmental variable (current velocity or depth). Eight species were associated with the woody habitat, with three of these, E. radiatus, E. unitaeniatus, and P. ngamensis being almost exclusively associated with this habitat. Enteromius kerstenii, E. lineomaculatus and S. depressirostris were almost exclusively associated with P. mauritianus and represent potential indicator species for this habitat. A number of species were also with both P. mauritianus and woody habitats. Nine species showed statistically significant associations with the rocky mesohabitat, with Amphilius uranoscopus and Petrocephalus longicapitis, being almost exclusive to rocky sections of the river. Therefore, species such as A. uranoscopus are potential indicators for monitoring the integrity of rocky habitats under threat from sedimentation. The strong associations indicate that this comprehensive baseline may be valuable indicators/ proxies for identifying anthropogenic induced change in the Kabompo basin. This would provide a basis to determine fish responses to regional environmental changes associated with human activities. , Thesis (MSc) -- Faculty of Science, Ichthyology & Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Rennie, Craig Lawrence
- Date: 2022-04-06
- Subjects: Biodiversity Zambia Kabompo District , Ecology Zambia Kabompo District , Fish communities Zambia Kabompo District , Fishes Ecology Zambia Kabompo District , Freshwater habitats Zambia Kabompo District , Fishes Effect of human beings on Zambia Kabompo District , Fishes Climatic factors Zambia Kabompo District , Mesohabitat
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232261 , vital:49976
- Description: The Zambezian headwaters contain diverse fish communities which support thriving fisheries. This region and its fishes are under pressure from multiple anthropogenic threats, including overexploitation and large-scale developments with potential knock-on effects for the riparian communities. Previous studies have focused on known fisheries areas and the mainstem Zambezi River, neglecting large tributaries such as the Kabompo River. Consequently, little literature is available on the diversity and ecology of the fishes that inhabit these large tributaries, hindering the effective management and protection of biodiversity. This study aimed to fill the current knowledge gaps in the diversity and habitat associations of fish communities in the Upper Zambezi, using the Kabompo River as a case study. The first objective was to provide an updated checklist of the fishes of the Kabompo River basin using a compilation of historical data and field surveys. This study detailed the occurrence and distribution of 83 fish species within the Kabompo River basin. All these species have been recorded in the Upper Zambezi, with some of their ranges extending into the Middle (29 species) and Lower Zambezi (23 species) while others have more restricted distributions. The most diverse families were the Cyprinidae (26 species) and the Cichlidae (15 species). A number of potential undescribed species, whose taxonomic distinctiveness need further investigation were also collected. Taxonomic conflicts are also highlighted for some of the taxa that were previously considered to have broad geographic ranges or disjunct distributions. Consistent with findings from other studies within the region, the current taxonomy underestimates the diversity of fishes in the Kabompo River and Upper Zambezi. The second objective was to assess the habitat use of small-bodied fish communities during the low-flow period in 2019. Reconnaissance trips identified dominant mesohabitats along the middle Kabompo River around Jivundu. A total of 139 mesohabitats were sampled across the five dominant mesohabitats identified; Phragmites mauritianus, wood, rock, Vallisneria aethiopica and bare substrate. Catch per unit effort, species richness, Shannon diversity and Pielou’s evenness differed significantly between these mesohabitats. Twenty-six species showed significant associations (p < 0.05) with a specific mesohabitat type or environmental variable (current velocity or depth). Eight species were associated with the woody habitat, with three of these, E. radiatus, E. unitaeniatus, and P. ngamensis being almost exclusively associated with this habitat. Enteromius kerstenii, E. lineomaculatus and S. depressirostris were almost exclusively associated with P. mauritianus and represent potential indicator species for this habitat. A number of species were also with both P. mauritianus and woody habitats. Nine species showed statistically significant associations with the rocky mesohabitat, with Amphilius uranoscopus and Petrocephalus longicapitis, being almost exclusive to rocky sections of the river. Therefore, species such as A. uranoscopus are potential indicators for monitoring the integrity of rocky habitats under threat from sedimentation. The strong associations indicate that this comprehensive baseline may be valuable indicators/ proxies for identifying anthropogenic induced change in the Kabompo basin. This would provide a basis to determine fish responses to regional environmental changes associated with human activities. , Thesis (MSc) -- Faculty of Science, Ichthyology & Fisheries Science, 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
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
Adolescents and coaches/trainers perspectives of ergogenic sports supplement use within South African private high schools
- Authors: Butler, Nicholas John
- Date: 2022-04-06
- Subjects: Dietary supplements , Energy metabolism , Teenagers South Africa , Teenagers Physiology South Africa , Teenagers Substance use South Africa , Coaches (Athletics) South Africa , Athletic trainers South Africa , Private schools South Africa , Ergogenic aids
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232443 , vital:49992
- Description: Sports supplements, also referred to as ergogenic aids, are used because of the assertion that they can enhance physical or athletic performance and/or physical appearance. Commonly used sports supplements include creatines, proteins, amino acids, stimulants, and in some cases pro-hormones. There is a relatively high and increasing prevalence of sports supplement use by the general population globally and in South Africa, particularly among adolescents and young adults due to various factors. While some research has explored supplement use among adolescents in a school setting, no study has explored this across the private school system in South Africa. Additionally, given the important role that coaches/trainers play in adolescent development, it is critical to also understand the role that they play regarding adolescent supplement use, given that there has been limited research around this topic in South Africa. Therefore, there were two aims of this study; Firstly, this study explored the prevalence and perceptions (knowledge; attitudes; beliefs) of sports supplements among South African private high school adolescents. Secondly, this study explored the perceptions (knowledge; attitudes; application of knowledge) towards sports supplements among adolescent coaches/trainers in South African private high schools. Considering the dual aim of this study, this thesis was structured as a two-part research study. Both parts took the form of a cross-sectional design, using an online questionnaire to collect qualitative and quantitative data. In total, a cohort of n=50 adolescents and n=49 coaches/trainers participated. Adolescent participants reported a high prevalence of sports supplement use (62%) with their main reasons for using them being recovery and performance. Adolescents were primarily influenced/advised by friends and coaches/trainers to start using sports supplements. Coaches/trainers primarily relied on other coaches/trainers and internet advertising/sites as a main source of information. Less than half of the participants from both groups reported having any formal education or training related to sports nutrition or sports supplements. Both groups thought that these products are being misused by adolescents, which may account for why a portion of the adolescent participants reported experiencing adverse side-effects from using sports supplements, and a few coach/trainer participants reported witnessing this in their practice. This may be a result of the professionalisation of school sport which places pressure on athletes and their coaches/trainers to perform and may in turn be the reason why some adolescents reported that they would use, and some coaches/trainers reported they would recommend the use of sports supplements even if they were aware of risk/dangers involved. Thus, there is a need for education/training among South African high school adolescents and their coaches/trainers with respect to the use of sports supplements, so that they can make informed decisions from reliable sources of information or advice in order to use these products safely and effectively. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2022
- Full Text:
- Date Issued: 2022-04-06
- Authors: Butler, Nicholas John
- Date: 2022-04-06
- Subjects: Dietary supplements , Energy metabolism , Teenagers South Africa , Teenagers Physiology South Africa , Teenagers Substance use South Africa , Coaches (Athletics) South Africa , Athletic trainers South Africa , Private schools South Africa , Ergogenic aids
- Language: English
- Type: Master's thesis , text
- Identifier: http://hdl.handle.net/10962/232443 , vital:49992
- Description: Sports supplements, also referred to as ergogenic aids, are used because of the assertion that they can enhance physical or athletic performance and/or physical appearance. Commonly used sports supplements include creatines, proteins, amino acids, stimulants, and in some cases pro-hormones. There is a relatively high and increasing prevalence of sports supplement use by the general population globally and in South Africa, particularly among adolescents and young adults due to various factors. While some research has explored supplement use among adolescents in a school setting, no study has explored this across the private school system in South Africa. Additionally, given the important role that coaches/trainers play in adolescent development, it is critical to also understand the role that they play regarding adolescent supplement use, given that there has been limited research around this topic in South Africa. Therefore, there were two aims of this study; Firstly, this study explored the prevalence and perceptions (knowledge; attitudes; beliefs) of sports supplements among South African private high school adolescents. Secondly, this study explored the perceptions (knowledge; attitudes; application of knowledge) towards sports supplements among adolescent coaches/trainers in South African private high schools. Considering the dual aim of this study, this thesis was structured as a two-part research study. Both parts took the form of a cross-sectional design, using an online questionnaire to collect qualitative and quantitative data. In total, a cohort of n=50 adolescents and n=49 coaches/trainers participated. Adolescent participants reported a high prevalence of sports supplement use (62%) with their main reasons for using them being recovery and performance. Adolescents were primarily influenced/advised by friends and coaches/trainers to start using sports supplements. Coaches/trainers primarily relied on other coaches/trainers and internet advertising/sites as a main source of information. Less than half of the participants from both groups reported having any formal education or training related to sports nutrition or sports supplements. Both groups thought that these products are being misused by adolescents, which may account for why a portion of the adolescent participants reported experiencing adverse side-effects from using sports supplements, and a few coach/trainer participants reported witnessing this in their practice. This may be a result of the professionalisation of school sport which places pressure on athletes and their coaches/trainers to perform and may in turn be the reason why some adolescents reported that they would use, and some coaches/trainers reported they would recommend the use of sports supplements even if they were aware of risk/dangers involved. Thus, there is a need for education/training among South African high school adolescents and their coaches/trainers with respect to the use of sports supplements, so that they can make informed decisions from reliable sources of information or advice in order to use these products safely and effectively. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2022
- Full Text:
- Date Issued: 2022-04-06