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Molecular Detection of Antibiotic-Resistant Genes in Pseudomonas aeruginosa from Nonclinical Environment: Public Health Implications in Mthatha, Eastern Cape Province, South Africa
- Mojisola Clara Hosu, Sandeep Vasaikar, Grace Emily Okuthe, Teke Apalata
- Authors: Mojisola Clara Hosu , Sandeep Vasaikar , Grace Emily Okuthe , Teke Apalata
- Date: 5 January 2021
- Subjects: Microbiology
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/2417 , vital:41877
- Description: Evaluation of resistant profiles and detection of antimicrobial-resistant genes of bacterial pathogens in the nonclinical milieu is imperative to assess the probable risk of dissemination of resistant genes in the environment. .is paper sought to identify antibiotic-resistant genes in Pseudomonas aeruginosa from nonclinical sources in Mthatha, Eastern Cape, and evaluate its public health implications. Samples collected from abattoir wastewater and aquatic environment were processed by membrane filtration and cultured on CHROMagarTM Pseudomonas medium. Species identification was performed by autoSCAN-4 (Dade Behring Inc., IL). Molecular characterization of the isolates was confirmed using real-time polymerase chain reaction (rPCR) and selected isolates were further screened for the possibility of harboring antimicrobial resistance genes. Fifty-one Pseudomonas species were recovered from abattoir wastewater and surface water samples, out of which thirty-six strains were Pseudomonas aeruginosa (70.6%). .e P. aeruginosa isolates demonstrated resistance to aztreonam (86.1%), ceftazidime (63.9%), piperacillin (58.3%), cefepime (55.6%), imipenem (50%), piperacillin/tazobactam (47.2%), meropenem (41.7%), and levofloxacin (30.6%). Twenty out of thirty-six P. aeruginosa displayed multidrug resistance profiles and were classified as multidrug-resistant (MDR) (55.6%). Most of the bacterial isolates exhibited a high Multiple Antibiotic Resistance (MAR) Index ranging from 0.08 to 0.69 with a mean MAR index of 0.38. In the rPCR analysis of fifteen P. aeruginosa isolates, 14 isolates (93.3%) were detected harboring blaSHV, six isolates (40%) harbored blaTEM, and three isolates (20%) harbored blaCTX-M, being the least occurring ESBL. Results of the current study revealed that P. aeruginosa isolates recovered from nonclinical milieu are resistant to frontline clinically relevant antipseudomonal drugs. .is is concerning as it poses a risk to the environment and constitutes a public health threat. Given the public health relevance, the paper recommends monitoring of multidrug-resistant pathogens in effluent environments.
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- Authors: Mojisola Clara Hosu , Sandeep Vasaikar , Grace Emily Okuthe , Teke Apalata
- Date: 5 January 2021
- Subjects: Microbiology
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/2417 , vital:41877
- Description: Evaluation of resistant profiles and detection of antimicrobial-resistant genes of bacterial pathogens in the nonclinical milieu is imperative to assess the probable risk of dissemination of resistant genes in the environment. .is paper sought to identify antibiotic-resistant genes in Pseudomonas aeruginosa from nonclinical sources in Mthatha, Eastern Cape, and evaluate its public health implications. Samples collected from abattoir wastewater and aquatic environment were processed by membrane filtration and cultured on CHROMagarTM Pseudomonas medium. Species identification was performed by autoSCAN-4 (Dade Behring Inc., IL). Molecular characterization of the isolates was confirmed using real-time polymerase chain reaction (rPCR) and selected isolates were further screened for the possibility of harboring antimicrobial resistance genes. Fifty-one Pseudomonas species were recovered from abattoir wastewater and surface water samples, out of which thirty-six strains were Pseudomonas aeruginosa (70.6%). .e P. aeruginosa isolates demonstrated resistance to aztreonam (86.1%), ceftazidime (63.9%), piperacillin (58.3%), cefepime (55.6%), imipenem (50%), piperacillin/tazobactam (47.2%), meropenem (41.7%), and levofloxacin (30.6%). Twenty out of thirty-six P. aeruginosa displayed multidrug resistance profiles and were classified as multidrug-resistant (MDR) (55.6%). Most of the bacterial isolates exhibited a high Multiple Antibiotic Resistance (MAR) Index ranging from 0.08 to 0.69 with a mean MAR index of 0.38. In the rPCR analysis of fifteen P. aeruginosa isolates, 14 isolates (93.3%) were detected harboring blaSHV, six isolates (40%) harbored blaTEM, and three isolates (20%) harbored blaCTX-M, being the least occurring ESBL. Results of the current study revealed that P. aeruginosa isolates recovered from nonclinical milieu are resistant to frontline clinically relevant antipseudomonal drugs. .is is concerning as it poses a risk to the environment and constitutes a public health threat. Given the public health relevance, the paper recommends monitoring of multidrug-resistant pathogens in effluent environments.
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VIVA Comrade Moss
- NUMSA
- Authors: NUMSA
- Date: 25 April
- Subjects: NUMSA
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/109640 , vital:33163 , SALHA 14b : NUMSA
- Description: The last 'Trial Update" reported on Comrade Moss’s case until mid-March. This report covers the period from that time up until 25th April.STADLER - "ANC EXPERT" Brigadier Stadler testified that the ANC had made certain calls to organisations within the country which, according to his "research", had been followed by organisations in the country. As examples he gave the ANC’s call for ungovernability, the formation of organs of people’s power and the destruction of town councils. During cross-examination Stadler conceded that he was not able to give examples of any direct link between the ANC and organisations inside the coutry but he said an inference could be drawn by looking at the ANC’s call and the behaviour of organisations inside the country.
- Full Text:
- Date Issued: 25 April
- Authors: NUMSA
- Date: 25 April
- Subjects: NUMSA
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/109640 , vital:33163 , SALHA 14b : NUMSA
- Description: The last 'Trial Update" reported on Comrade Moss’s case until mid-March. This report covers the period from that time up until 25th April.STADLER - "ANC EXPERT" Brigadier Stadler testified that the ANC had made certain calls to organisations within the country which, according to his "research", had been followed by organisations in the country. As examples he gave the ANC’s call for ungovernability, the formation of organs of people’s power and the destruction of town councils. During cross-examination Stadler conceded that he was not able to give examples of any direct link between the ANC and organisations inside the coutry but he said an inference could be drawn by looking at the ANC’s call and the behaviour of organisations inside the country.
- Full Text:
- Date Issued: 25 April
Morphology, histology and histochemistry of the digestive tract of the Banded tilapia, Tilapia sparrmanii (Perciformes: Cichlidae)
- Grace E. Okuthe, Bongile Bhomela
- Authors: Grace E. Okuthe , Bongile Bhomela
- Date: December 23, 2020
- Subjects: Fish, gastrointestinal tract, histo-architecture
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/2425 , vital:41881
- Description: ABSTRACT. This study described anatomical, histological and histochemical features of the mucosal layer of the digestive tract of Tilapia sparrmanii Smith, 1840, an omnivorous freshwater fish endemic to Southern Africa. This species exhibited a short thick oesophagus with long deep longitudinal folds (466.68 ± 16.91 µm), and a thick (173.50 ± 10.92 µm) muscular layer that allow the passage of large food items. The mucosa was lined with stratified secretory epithelium rich in goblet cells that secreted neutral and acid mucins. The stomach was a sac-like structure with simple tubular glands surrounded by connective tissue. The mucosa was lined with simple columnar epithelium and the lamina propria exhibited a well-developed layer of gastric glands that occupied the entire length of the cardio-fundic region. The stomach mucosa consisted of epithelial cells with intense neutral mucin secretion which protects against gastric juice. Neck cells of gastric glands synthesized neutral and acid mucins. The intestine was highly coiled and presented a complex pattern of transversal folds internally (villi). Villi length decreased progressively from the anterior to the posterior intestine (p < 0.0001). Tunica muscularis of the mid-intestine had the thinnest thickness among all parts of the intestine (p < 0.0001). Goblet cells whose numbers increased towards the rectum secreted both acid and neutral mucins. The results indicate structural similarities of T. sparrmanii GIT with other tilapia species and will be useful for understanding the physiology of the digestive systems as well as functional components of the GIT.
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- Authors: Grace E. Okuthe , Bongile Bhomela
- Date: December 23, 2020
- Subjects: Fish, gastrointestinal tract, histo-architecture
- Language: English
- Type: Journal Article
- Identifier: http://hdl.handle.net/11260/2425 , vital:41881
- Description: ABSTRACT. This study described anatomical, histological and histochemical features of the mucosal layer of the digestive tract of Tilapia sparrmanii Smith, 1840, an omnivorous freshwater fish endemic to Southern Africa. This species exhibited a short thick oesophagus with long deep longitudinal folds (466.68 ± 16.91 µm), and a thick (173.50 ± 10.92 µm) muscular layer that allow the passage of large food items. The mucosa was lined with stratified secretory epithelium rich in goblet cells that secreted neutral and acid mucins. The stomach was a sac-like structure with simple tubular glands surrounded by connective tissue. The mucosa was lined with simple columnar epithelium and the lamina propria exhibited a well-developed layer of gastric glands that occupied the entire length of the cardio-fundic region. The stomach mucosa consisted of epithelial cells with intense neutral mucin secretion which protects against gastric juice. Neck cells of gastric glands synthesized neutral and acid mucins. The intestine was highly coiled and presented a complex pattern of transversal folds internally (villi). Villi length decreased progressively from the anterior to the posterior intestine (p < 0.0001). Tunica muscularis of the mid-intestine had the thinnest thickness among all parts of the intestine (p < 0.0001). Goblet cells whose numbers increased towards the rectum secreted both acid and neutral mucins. The results indicate structural similarities of T. sparrmanii GIT with other tilapia species and will be useful for understanding the physiology of the digestive systems as well as functional components of the GIT.
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Anticholinesterase and Antioxidant Activities of Spilanthes filicaulis Whole Plant Extracts for the Management of Alzheimer’s Disease
- Authors: Adebola O. Oyedeji
- Date: July 23, 2019
- Language: English
- Identifier: http://hdl.handle.net/11260/1488 , vital:37602
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- Authors: Adebola O. Oyedeji
- Date: July 23, 2019
- Language: English
- Identifier: http://hdl.handle.net/11260/1488 , vital:37602
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The prevalence of insufficient iodine intake in pregnancy in Africa: Protocol for a systematic review and meta-analysis
- Charles Bitamazire Businge, Benjamin Longo-Mbenza, Andre Pascal Kengne
- Authors: Charles Bitamazire Businge , Benjamin Longo-Mbenza , Andre Pascal Kengne
- Date: 22-8-2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3387 , vital:43338 , https://systematicreviewsjournal.biomedcentral.com/articles/10.1186/s13643-019-1092-7#citeas
- Description: Background: Insufficient iodine intake in pregnancy is associated with many adverse pregnancy outcomes. About 90% of African countries are at risk of iodine deficiency due to poor soils and dietary goitrogens. Pregnancy predisposes to insufficient iodine nutrition secondary to increased physiological demand and increased renal loss. Iodine deficiency is re-emerging in countries thought to be replete with pregnant women being the most affected. This review seeks to identify the degree of iodine nutrition in pregnancy on the entire African continent before and after the implementation of national iodization programmes. Methods: A systematic search of published literature will be conducted for observational studies that directly determined the prevalence of insufficient iodine intake among pregnant women in Africa. Electronic databases and grey literature will be searched for baseline data before the implementation of population-based iodine supplementation and for follow-up data up to December 2018. Screening of identified articles and data extraction will be conducted independently by two investigators. Risk of bias and methodological quality of the included studies will be assessed using a risk of bias tool. Appropriate meta-analytic techniques will be used to pool prevalence estimates from studies with similar features, overall and by major characteristics including the region of the study, time period (before and after implementation of iodization programmes), sample size and age. Heterogeneity of the estimates across studies will be quantified and publication bias investigated. This protocol is reported according to Preferred Reporting Items for Systematic reviews and Meta-Analysis protocols (PRISMA-P) 2015 guidelines. Discussion This review will help ascertain the impact of national iodization programmes on the iodine nutrition status in pregnancy in Africa and advise policy on the necessity for monitoring and mitigating iodine deficiency in pregnancy in Africa. This review is part of a thesis that will be submitted to the Faculty of Health Sciences, University of Cape Town, for the award of a PhD in Medicine whose protocol has been granted ethics approval (UCT HREC 135/2018). In addition, the results will be published in a peer-reviewed journal.
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- Date Issued: 22-8-2019
- Authors: Charles Bitamazire Businge , Benjamin Longo-Mbenza , Andre Pascal Kengne
- Date: 22-8-2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3387 , vital:43338 , https://systematicreviewsjournal.biomedcentral.com/articles/10.1186/s13643-019-1092-7#citeas
- Description: Background: Insufficient iodine intake in pregnancy is associated with many adverse pregnancy outcomes. About 90% of African countries are at risk of iodine deficiency due to poor soils and dietary goitrogens. Pregnancy predisposes to insufficient iodine nutrition secondary to increased physiological demand and increased renal loss. Iodine deficiency is re-emerging in countries thought to be replete with pregnant women being the most affected. This review seeks to identify the degree of iodine nutrition in pregnancy on the entire African continent before and after the implementation of national iodization programmes. Methods: A systematic search of published literature will be conducted for observational studies that directly determined the prevalence of insufficient iodine intake among pregnant women in Africa. Electronic databases and grey literature will be searched for baseline data before the implementation of population-based iodine supplementation and for follow-up data up to December 2018. Screening of identified articles and data extraction will be conducted independently by two investigators. Risk of bias and methodological quality of the included studies will be assessed using a risk of bias tool. Appropriate meta-analytic techniques will be used to pool prevalence estimates from studies with similar features, overall and by major characteristics including the region of the study, time period (before and after implementation of iodization programmes), sample size and age. Heterogeneity of the estimates across studies will be quantified and publication bias investigated. This protocol is reported according to Preferred Reporting Items for Systematic reviews and Meta-Analysis protocols (PRISMA-P) 2015 guidelines. Discussion This review will help ascertain the impact of national iodization programmes on the iodine nutrition status in pregnancy in Africa and advise policy on the necessity for monitoring and mitigating iodine deficiency in pregnancy in Africa. This review is part of a thesis that will be submitted to the Faculty of Health Sciences, University of Cape Town, for the award of a PhD in Medicine whose protocol has been granted ethics approval (UCT HREC 135/2018). In addition, the results will be published in a peer-reviewed journal.
- Full Text:
- Date Issued: 22-8-2019
A decision-making model to guide securing blockchain deployments
- Authors: Cronje, Gerhard Roets
- Date: 2021-10
- Subjects: Blockchains (Databases) , Bitcoin , Cryptocurrencies , Distributed databases , Computer networks Security measures , Computer networks Security measures Decision making , Ethereum
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188865 , vital:44793
- Description: Satoshi Nakamoto, the pseudo-identity accredit with the paper that sparked the implementation of Bitcoin, is famously quoted as remarking, electronically of course, that “If you don’t believe it or don’t get it, I don’t have time to try and convince you, sorry” (Tsapis, 2019, p. 1). What is noticeable, 12 years after the famed Satoshi paper that initiated Bitcoin (Nakamoto, 2008), is that blockchain at the very least has staying power and potentially wide application. A lesser known figure Marc Kenisberg, founder of Bitcoin Chaser which is one of the many companies formed around the Bitcoin ecosystem, summarised it well saying “…Blockchain is the tech - Bitcoin is merely the first mainstream manifestation of its potential” (Tsapis, 2019, p. 1). With blockchain still trying to reach its potential and still maturing on its way towards a mainstream technology the main question that arises for security professionals is how do I ensure we do it securely? This research seeks to address that question by proposing a decision-making model that can be used by a security professional to guide them through ensuring appropriate security for blockchain deployments. This research is certainly not the first attempt at discussing the security of the blockchain and will not be the last, as the technology around blockchain and distributed ledger technology is still rapidly evolving. What this research does try to achieve is not to delve into extremely specific areas of blockchain security, or get bogged down in technical details, but to provide a reference framework that aims to cover all the major areas to be considered. The approach followed was to review the literature regarding blockchain and to identify the main security areas to be addressed. It then proposes a decision-making model and tests the model against a fictitious but relevant real-world example. It concludes with learnings from this research. The reader can be the judge, but the model aims to be a practical valuable resource to be used by any security professional, to navigate the security aspects logically and understandably when being involved in a blockchain deployment. In contrast to the Satoshi quote, this research tries to convince the reader and assist him/her in understanding the security choices related to every blockchain deployment. , Thesis (MSc) -- Faculty of Science, Computer Science, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Cronje, Gerhard Roets
- Date: 2021-10
- Subjects: Blockchains (Databases) , Bitcoin , Cryptocurrencies , Distributed databases , Computer networks Security measures , Computer networks Security measures Decision making , Ethereum
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188865 , vital:44793
- Description: Satoshi Nakamoto, the pseudo-identity accredit with the paper that sparked the implementation of Bitcoin, is famously quoted as remarking, electronically of course, that “If you don’t believe it or don’t get it, I don’t have time to try and convince you, sorry” (Tsapis, 2019, p. 1). What is noticeable, 12 years after the famed Satoshi paper that initiated Bitcoin (Nakamoto, 2008), is that blockchain at the very least has staying power and potentially wide application. A lesser known figure Marc Kenisberg, founder of Bitcoin Chaser which is one of the many companies formed around the Bitcoin ecosystem, summarised it well saying “…Blockchain is the tech - Bitcoin is merely the first mainstream manifestation of its potential” (Tsapis, 2019, p. 1). With blockchain still trying to reach its potential and still maturing on its way towards a mainstream technology the main question that arises for security professionals is how do I ensure we do it securely? This research seeks to address that question by proposing a decision-making model that can be used by a security professional to guide them through ensuring appropriate security for blockchain deployments. This research is certainly not the first attempt at discussing the security of the blockchain and will not be the last, as the technology around blockchain and distributed ledger technology is still rapidly evolving. What this research does try to achieve is not to delve into extremely specific areas of blockchain security, or get bogged down in technical details, but to provide a reference framework that aims to cover all the major areas to be considered. The approach followed was to review the literature regarding blockchain and to identify the main security areas to be addressed. It then proposes a decision-making model and tests the model against a fictitious but relevant real-world example. It concludes with learnings from this research. The reader can be the judge, but the model aims to be a practical valuable resource to be used by any security professional, to navigate the security aspects logically and understandably when being involved in a blockchain deployment. In contrast to the Satoshi quote, this research tries to convince the reader and assist him/her in understanding the security choices related to every blockchain deployment. , Thesis (MSc) -- Faculty of Science, Computer Science, 2021
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- Date Issued: 2021-10
A sustainability practices educational intervention in response to environmental matters of concern amongst Makhanda youth
- Authors: Musiyiwa, Fungayi Lona
- Date: 2021-10
- Subjects: Sustainable living South Africa Makhanda , Social learning South Africa Makhanda , Eco clubs South Africa Makhanda , Environmental education Activity programs South Africa Makhanda , Youth in development South Africa Makhanda , Youth Social conditions
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/188364 , vital:44747
- Description: This study responded to urbanisation as one of the challenges affecting youths’ lifestyles in this century. Children and youth around the world are living in overpopulated, polluted and unsafe environments which fail to produce opportunities for learning, play and recreation (World Health Organisation [WHO], 2017). This study explored these issues in the context of Makhanda with an intervention to engage youth in sustainability practices, to help them to strengthen sustainable lifestyles. The participants in this research were members of two eco-clubs from two schools in Makhanda ranging in age from 12-14 years (primary school) and 15-17 years (high school). The study explored how learning processes within a club intervention contributed to the well- being of participating youth and their capacity to live sustainable and fulfilling lives. The research explored (with participants) eight themes as matters of concern namely, ‘education’, ‘home-life’, ‘energy use’, ‘mobility’, ‘leisure and communication’, ‘waste’, ‘water’ and ‘food’. Detailed case narratives exploring Wals’ social learning stages were used to explore the themes. These themes were explored through photo narratives of the youths’ lives and matters of concern in sustainability issues, risks and practices emanating from the Makhanda context. The pedagogical framework for the intervention was guided by Wals’ social learning framework for mobilizing sustainability practices. Social learning interaction took place through all the stages of the framework and the challenges and potentials of the educational intervention were explored in relation to each stage. From the six themes suggested above the youth chose food and water as themes to take forward as a response project. The project pursued was a vegetable garden in which the youth were actively engaged in order to seek and try out sustainable ways of living. An interpretive approach was used within the interpretive paradigm. Qualitative data were generated through focus group discussions, observations, individual interviews and document analysis. Practice architectures theory was used analytically to explore the dynamics of the emergent sustainability practices initiated by the eco-club youth. I used it as a change method and a tool for initiating social learning actions for ‘sustainability practices’ projects. The study indicated that the youth’s key challenges affecting sustainability of their lifestyles are: lack of access to basic infrastructure, recreational facilities, electricity supply, transport, security and water. In this study, it was clear that much of the youth’s involvement in these matters of concern and sustainability issues was at the level of participating in the six themes through Wals’ social learning processes. This allowed youths to develop their knowledge and skills on how to participate in the gardening project rather than simply focusing on the environmental matters of concern in question. The Handprint Resource Books have been designed for educators who are looking for practical ideas to work with in the learning areas of the National Curriculum. The focus is on sustainability practices that can be taken up within the perspective that each learning area brings to environment and sustainability concerns. The use of the Handprint Resource Books promoted active youth participation and interaction encouraging youth to be reflective thinkers, which led to understanding of the issues and the sustainability practices that emerged during the discussions. The Handprint Resource Books focused on sustainability practices within the learning area of environment and sustainability concerns. Due to her facilitation skills, an environmental expert’s presentation on a sustainability topic enabled youths to select the intended project. The involvement of youth in the implementation of the vegetable garden as a sustainability practice empowered youth to be more confident in engaging in a collective action for change as they developed the capability to share and start their own vegetable gardens at their homes. , Thesis (MEd) -- Faculty of Education, Environmental Learning Research Centre, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Musiyiwa, Fungayi Lona
- Date: 2021-10
- Subjects: Sustainable living South Africa Makhanda , Social learning South Africa Makhanda , Eco clubs South Africa Makhanda , Environmental education Activity programs South Africa Makhanda , Youth in development South Africa Makhanda , Youth Social conditions
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/188364 , vital:44747
- Description: This study responded to urbanisation as one of the challenges affecting youths’ lifestyles in this century. Children and youth around the world are living in overpopulated, polluted and unsafe environments which fail to produce opportunities for learning, play and recreation (World Health Organisation [WHO], 2017). This study explored these issues in the context of Makhanda with an intervention to engage youth in sustainability practices, to help them to strengthen sustainable lifestyles. The participants in this research were members of two eco-clubs from two schools in Makhanda ranging in age from 12-14 years (primary school) and 15-17 years (high school). The study explored how learning processes within a club intervention contributed to the well- being of participating youth and their capacity to live sustainable and fulfilling lives. The research explored (with participants) eight themes as matters of concern namely, ‘education’, ‘home-life’, ‘energy use’, ‘mobility’, ‘leisure and communication’, ‘waste’, ‘water’ and ‘food’. Detailed case narratives exploring Wals’ social learning stages were used to explore the themes. These themes were explored through photo narratives of the youths’ lives and matters of concern in sustainability issues, risks and practices emanating from the Makhanda context. The pedagogical framework for the intervention was guided by Wals’ social learning framework for mobilizing sustainability practices. Social learning interaction took place through all the stages of the framework and the challenges and potentials of the educational intervention were explored in relation to each stage. From the six themes suggested above the youth chose food and water as themes to take forward as a response project. The project pursued was a vegetable garden in which the youth were actively engaged in order to seek and try out sustainable ways of living. An interpretive approach was used within the interpretive paradigm. Qualitative data were generated through focus group discussions, observations, individual interviews and document analysis. Practice architectures theory was used analytically to explore the dynamics of the emergent sustainability practices initiated by the eco-club youth. I used it as a change method and a tool for initiating social learning actions for ‘sustainability practices’ projects. The study indicated that the youth’s key challenges affecting sustainability of their lifestyles are: lack of access to basic infrastructure, recreational facilities, electricity supply, transport, security and water. In this study, it was clear that much of the youth’s involvement in these matters of concern and sustainability issues was at the level of participating in the six themes through Wals’ social learning processes. This allowed youths to develop their knowledge and skills on how to participate in the gardening project rather than simply focusing on the environmental matters of concern in question. The Handprint Resource Books have been designed for educators who are looking for practical ideas to work with in the learning areas of the National Curriculum. The focus is on sustainability practices that can be taken up within the perspective that each learning area brings to environment and sustainability concerns. The use of the Handprint Resource Books promoted active youth participation and interaction encouraging youth to be reflective thinkers, which led to understanding of the issues and the sustainability practices that emerged during the discussions. The Handprint Resource Books focused on sustainability practices within the learning area of environment and sustainability concerns. Due to her facilitation skills, an environmental expert’s presentation on a sustainability topic enabled youths to select the intended project. The involvement of youth in the implementation of the vegetable garden as a sustainability practice empowered youth to be more confident in engaging in a collective action for change as they developed the capability to share and start their own vegetable gardens at their homes. , Thesis (MEd) -- Faculty of Education, Environmental Learning Research Centre, 2021
- Full Text:
- Date Issued: 2021-10
An interpretive analysis of the experiences of adults working as university support staff
- Authors: Zini, Thembela Nomonde
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188888 , vital:44795
- Description: Work means different things to different people and the different meanings they make of their work has the unique ability of contributing to a sense of identity. Support staff have to negotiate their personal identities and social identities to develop a work identity in the complex South African context that has its unique challenges. Exploring how support staff make sense of their experiences, when it comes to their identities, reveals what identity work strategies they use. An interpretative phenomenological method of inquiry was employed as an initial research method to explore the aspects that impact on the identity formation of support staff at Rhodes University. The study aims to investigate how support staff have constructed a work identity through their constructions of their experiences. Six participants were recruited through a purposive sampling method and data were collected using semi-structured interviews. The study revealed that support staff use the following identity work strategies to negotiate their identities: Financial, Personality, Career mobility, Roles, Status and Esteem, Subjective wellbeing. These themes were derived from the narratives of the participants, using the emphases in the data and suggest that support staff use identity work strategies both outside and within the workplace, when constructing their work identities. The study illustrates that as people ascribe different meanings to work, they will define and negotiate their identities in the workplace based upon those meanings. Identity work is indeed challenging for support staff because they need to use identity strategies that are enhancing to their self-esteem. Identity work is a challenging task because of the many tensions and demands of modern society, as adults negotiate their needs to provide for families and to find ways to construct their job status in positive ways. , Thesis (MA) -- Faculty of Humanities, Psychology, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Zini, Thembela Nomonde
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188888 , vital:44795
- Description: Work means different things to different people and the different meanings they make of their work has the unique ability of contributing to a sense of identity. Support staff have to negotiate their personal identities and social identities to develop a work identity in the complex South African context that has its unique challenges. Exploring how support staff make sense of their experiences, when it comes to their identities, reveals what identity work strategies they use. An interpretative phenomenological method of inquiry was employed as an initial research method to explore the aspects that impact on the identity formation of support staff at Rhodes University. The study aims to investigate how support staff have constructed a work identity through their constructions of their experiences. Six participants were recruited through a purposive sampling method and data were collected using semi-structured interviews. The study revealed that support staff use the following identity work strategies to negotiate their identities: Financial, Personality, Career mobility, Roles, Status and Esteem, Subjective wellbeing. These themes were derived from the narratives of the participants, using the emphases in the data and suggest that support staff use identity work strategies both outside and within the workplace, when constructing their work identities. The study illustrates that as people ascribe different meanings to work, they will define and negotiate their identities in the workplace based upon those meanings. Identity work is indeed challenging for support staff because they need to use identity strategies that are enhancing to their self-esteem. Identity work is a challenging task because of the many tensions and demands of modern society, as adults negotiate their needs to provide for families and to find ways to construct their job status in positive ways. , Thesis (MA) -- Faculty of Humanities, Psychology, 2021
- Full Text:
- Date Issued: 2021-10
Echogenic liposomes for ultrasound-triggered drug delivery
- Authors: Izuchukwu, Ezekiel Charles
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188997 , vital:44805
- Description: Colorectal cancer is one of common cancers worldwide. It is the third most diagnosed cancer and the second leading cause of death. The use of 5-fluorouracil (5-FU) alone or in a chemotherapy regime has been the effective treatment of colorectal cancer patients. The efficacy of 5-FU in colorectal cancer treatment is significantly limited by drug resistance, gastrointestinal, and bone marrow toxicity through high-level expression of thymidylate synthase, justifying a need to improve its therapeutic index. Liposomes are colloidal membranes comprising of one or more lipid bilayers enclosing an aqueous core. They have been used to improve the therapeutic index of many anti-cancer drugs by changing drug absorption, elongating biological half-life, reducing metabolism, and reducing toxicity to healthy tissues. Echogenic liposomes are specifically designed to respond to external triggering like ultrasound stimulation by entrapping a gas or an emulsion that can vaporize. A liposome's unique property is that it can entrap both hydrophobic and hydrophilic substances simultaneously in the lipid bilayer and the aqueous core, respectively. These stimuli-responsive liposomes can be triggered externally with ultrasound, to release the chemotherapeutic cargo only at the required site. This research aims to formulate echogenic liposomes encapsulating 5-FU for potential ultrasound triggered release (echogenic). Liposome formulations wereprepared with lipid composition of crude soybean lecithin and cholesterol by thin-filmhydration method and the drug was passively loaded in the formulation. The 5-FU loadedliposomes were evaluated by dynamic light scattering (DLS) for particle size, polydispersityindex, and zeta potential and transmission electron microscopy (TEM) for morphology.Encapsulated liposomal formulations were also evaluated using physicochemical techniquesincluding thermogravimetric analysis (TGA), differential scanning calorimetry (DSC),Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Theencapsulation efficiency and release kinetics were studied using a validated high-performanceliquid chromatography (HPLC) method. Echogenic properties were explored by entrapping abiocompatible gas (argon) at the same time as the drug (5-FU) using a pressure/freezemethodology. The liposomal formulations were typically spherical with a size of about 150 nmand encapsulation efficiency of 62%. Low-frequency ultrasound (20 kHz) was used to triggerthe drug release from the complete formulation at 10%, 15%, and 20% amplitude and exposuretime of 5 min and 10 min. The rate of drug release from the nano-carrier was a function of theultrasound amplitude and exposure time and reached a maximum of 65% release under theconditions investigated. The cumulative release was investigated, with and without theapplication of ultrasound. It was demonstrated that the application of ultrasound resulted in complete release (99%) after 12 h while this dropped to 70% without ultrasound. These results are encouraging for optimizing ultrasound parameters for triggered and controlled release of the 5-FU, for conditions such as the management of cancer where low-power ultrasound can be applied. , Thesis (MSc) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Izuchukwu, Ezekiel Charles
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188997 , vital:44805
- Description: Colorectal cancer is one of common cancers worldwide. It is the third most diagnosed cancer and the second leading cause of death. The use of 5-fluorouracil (5-FU) alone or in a chemotherapy regime has been the effective treatment of colorectal cancer patients. The efficacy of 5-FU in colorectal cancer treatment is significantly limited by drug resistance, gastrointestinal, and bone marrow toxicity through high-level expression of thymidylate synthase, justifying a need to improve its therapeutic index. Liposomes are colloidal membranes comprising of one or more lipid bilayers enclosing an aqueous core. They have been used to improve the therapeutic index of many anti-cancer drugs by changing drug absorption, elongating biological half-life, reducing metabolism, and reducing toxicity to healthy tissues. Echogenic liposomes are specifically designed to respond to external triggering like ultrasound stimulation by entrapping a gas or an emulsion that can vaporize. A liposome's unique property is that it can entrap both hydrophobic and hydrophilic substances simultaneously in the lipid bilayer and the aqueous core, respectively. These stimuli-responsive liposomes can be triggered externally with ultrasound, to release the chemotherapeutic cargo only at the required site. This research aims to formulate echogenic liposomes encapsulating 5-FU for potential ultrasound triggered release (echogenic). Liposome formulations wereprepared with lipid composition of crude soybean lecithin and cholesterol by thin-filmhydration method and the drug was passively loaded in the formulation. The 5-FU loadedliposomes were evaluated by dynamic light scattering (DLS) for particle size, polydispersityindex, and zeta potential and transmission electron microscopy (TEM) for morphology.Encapsulated liposomal formulations were also evaluated using physicochemical techniquesincluding thermogravimetric analysis (TGA), differential scanning calorimetry (DSC),Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Theencapsulation efficiency and release kinetics were studied using a validated high-performanceliquid chromatography (HPLC) method. Echogenic properties were explored by entrapping abiocompatible gas (argon) at the same time as the drug (5-FU) using a pressure/freezemethodology. The liposomal formulations were typically spherical with a size of about 150 nmand encapsulation efficiency of 62%. Low-frequency ultrasound (20 kHz) was used to triggerthe drug release from the complete formulation at 10%, 15%, and 20% amplitude and exposuretime of 5 min and 10 min. The rate of drug release from the nano-carrier was a function of theultrasound amplitude and exposure time and reached a maximum of 65% release under theconditions investigated. The cumulative release was investigated, with and without theapplication of ultrasound. It was demonstrated that the application of ultrasound resulted in complete release (99%) after 12 h while this dropped to 70% without ultrasound. These results are encouraging for optimizing ultrasound parameters for triggered and controlled release of the 5-FU, for conditions such as the management of cancer where low-power ultrasound can be applied. , Thesis (MSc) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10
Establishing a water resources assessment system for Eswatini (Swaziland) incorporating data and modelling uncertainty
- Authors: Ndzabandzaba, Coli
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/189009 , vital:44806 , 10.21504/10962/189009
- Description: The uneven distribution of water resources availability globally puts pressure on environmental and human or socio-economic systems and has complex implications for the interactions within these systems. The natural environment and water resources are increasingly threatened by development, and water management crises are still occurring. This is exacerbated by the lack of accurate and adequate information on these systems. In Eswatini, for example, the pressure on the available water resources is mounting due to increasing water demand for irrigation while information about natural hydrological conditions and levels of water resources developments are uncertain. In addition, the practical application of hydrological models for water resources assessments that incorporate uncertainty in Eswatini has yet to be realised. The aim of the study, therefore, was to develop a water resource assessment system that is based on both observed and simulated information and that includes uncertainty. This study focusses on a regional water resource assessment using an uncertainty version of the Pitman monthly rainfall-runoff model whose outputs are constrained by six indices of natural hydrological response (i.e., mean monthly runoff, mean monthly groundwater recharge, Q10, Q50 and Q90 percentage points of the flow duration curve and % time of zero flows) for each of the 122 sub-basins of the transboundary catchments of Eswatini. A 2-step uncertainty modelling approach was tested, validated and then applied to all the sub-basins of Eswatini. The first step of the model run establishes behavioural, but uncertain model parameter ranges for natural incremental sub-basin hydrological responses and the model is typically run 100 000 times for each sub-basin. The parameter space that defines the uncertainty in parameter estimation is sampled based on simple Monte Carlo approach. The second step links all the sub-basin outputs and allows for water use parameters to be incorporated, where necessary, in order to generate cumulative sub-basin outflows. The results from the constraint index analysis have proved to be useful in constraining the model outputs. Generally, the behavioural model outputs produced realistic uncertainty estimates as well as acceptable simulations based on the assessment of the flow duration curves. The modelling results indicated that there is some degree of uncertainty that cannot be easily accounted for due to some identified data issues. The results also showed that there is still a possibility to improve the simulations provided such issues are resolved. The issues about the simulation of stream flow that were detected are mainly related to availability of data to estimate water use parameters. Another challenge in setting up the model was associated with establishing constraints that match the parameters for natural hydrological conditions for specific sub-basins and maintaining consistency in the adjustment of the model output constraints for other sub-basins. In an attempt to overcome this problem, the study recommends additional hydrological response constraints to be used with the Pitman model. Another main recommendation relates to the strong cooperation of relevant catchment management authorities and stakeholders including scientists in order to make information more available to users. The new hydrological insight is derived from the analysis of hydrological indices which highlighted the regional variations in hydrological processes and sub-basin response across the transboundary basins of Eswatini. The adopted modelling approach provides further insight into all the uncertainties associated with quantifying the available water resources of the country. The study has provided further understanding of the spatial variability of the hydrological response and existing development impacts than was previously available. It is envisaged that these new insights will provide an improved basis for future water management in Eswatini. , Thesis (PhD) -- Faculty of Science, Institute for Water Research, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Ndzabandzaba, Coli
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/189009 , vital:44806 , 10.21504/10962/189009
- Description: The uneven distribution of water resources availability globally puts pressure on environmental and human or socio-economic systems and has complex implications for the interactions within these systems. The natural environment and water resources are increasingly threatened by development, and water management crises are still occurring. This is exacerbated by the lack of accurate and adequate information on these systems. In Eswatini, for example, the pressure on the available water resources is mounting due to increasing water demand for irrigation while information about natural hydrological conditions and levels of water resources developments are uncertain. In addition, the practical application of hydrological models for water resources assessments that incorporate uncertainty in Eswatini has yet to be realised. The aim of the study, therefore, was to develop a water resource assessment system that is based on both observed and simulated information and that includes uncertainty. This study focusses on a regional water resource assessment using an uncertainty version of the Pitman monthly rainfall-runoff model whose outputs are constrained by six indices of natural hydrological response (i.e., mean monthly runoff, mean monthly groundwater recharge, Q10, Q50 and Q90 percentage points of the flow duration curve and % time of zero flows) for each of the 122 sub-basins of the transboundary catchments of Eswatini. A 2-step uncertainty modelling approach was tested, validated and then applied to all the sub-basins of Eswatini. The first step of the model run establishes behavioural, but uncertain model parameter ranges for natural incremental sub-basin hydrological responses and the model is typically run 100 000 times for each sub-basin. The parameter space that defines the uncertainty in parameter estimation is sampled based on simple Monte Carlo approach. The second step links all the sub-basin outputs and allows for water use parameters to be incorporated, where necessary, in order to generate cumulative sub-basin outflows. The results from the constraint index analysis have proved to be useful in constraining the model outputs. Generally, the behavioural model outputs produced realistic uncertainty estimates as well as acceptable simulations based on the assessment of the flow duration curves. The modelling results indicated that there is some degree of uncertainty that cannot be easily accounted for due to some identified data issues. The results also showed that there is still a possibility to improve the simulations provided such issues are resolved. The issues about the simulation of stream flow that were detected are mainly related to availability of data to estimate water use parameters. Another challenge in setting up the model was associated with establishing constraints that match the parameters for natural hydrological conditions for specific sub-basins and maintaining consistency in the adjustment of the model output constraints for other sub-basins. In an attempt to overcome this problem, the study recommends additional hydrological response constraints to be used with the Pitman model. Another main recommendation relates to the strong cooperation of relevant catchment management authorities and stakeholders including scientists in order to make information more available to users. The new hydrological insight is derived from the analysis of hydrological indices which highlighted the regional variations in hydrological processes and sub-basin response across the transboundary basins of Eswatini. The adopted modelling approach provides further insight into all the uncertainties associated with quantifying the available water resources of the country. The study has provided further understanding of the spatial variability of the hydrological response and existing development impacts than was previously available. It is envisaged that these new insights will provide an improved basis for future water management in Eswatini. , Thesis (PhD) -- Faculty of Science, Institute for Water Research, 2021
- Full Text:
- Date Issued: 2021-10
Evaluating the physiological, morphological and nutritional effects of elevated atmospheric CO2 and drought on select South African maize cultivars
- Authors: Bopape, Tebadi Mamadiga
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Master theses , text
- Identifier: http://hdl.handle.net/10962/189020 , vital:44807
- Description: Rainfed cropping systems in southern Africa are threatened by predicted changes in precipitation and atmospheric CO2. Maize based cropping systems are especially vulnerable in South Africa as yield losses due to these climatic changes are expected to reach 30% by 2030. Therefore, it is important to thoroughly understand the effects of climatic changes such as elevated atmospheric CO2 (eCO2) and climate change-induced drought on important crops such as maize. Climate change is predicted to have different effects in different Southern Africa regions, as the climate in the southern African region constitutes an arid western region and a sub-humid eastern region. Cultivar selection is very important as cultivars are developed based on the climatic conditions of the regions within which they will be grown. Results from free-air CO2 enrichment experiments in the Northern hemisphere conducted at 550 ppm have shown that C4 crops such as maize benefit from eCO2 only in the presence of environmental stressors such as drought. Studies done on eCO2 and drought have a great geographical bias as they have predominantly been performed in temperate, northern hemisphere climates. This is an issue since the effect of elevated CO2 varies with climate, it is necessary to address this by including data representative of warmer and more arid climates. Although CO2 concentration changes are uniform across the globe, the way crops respond to elevated CO2 depends on the prevailing environmental and climatic conditions in the region. The study's objective was to determine the effects of elevated CO2 and drought on the growth, yield and grain quality of South African maize cultivars bred for the semi-arid western and sub-humid eastern production regions. , Thesis (MSc) -- Faculty of Science, Botany, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Bopape, Tebadi Mamadiga
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Master theses , text
- Identifier: http://hdl.handle.net/10962/189020 , vital:44807
- Description: Rainfed cropping systems in southern Africa are threatened by predicted changes in precipitation and atmospheric CO2. Maize based cropping systems are especially vulnerable in South Africa as yield losses due to these climatic changes are expected to reach 30% by 2030. Therefore, it is important to thoroughly understand the effects of climatic changes such as elevated atmospheric CO2 (eCO2) and climate change-induced drought on important crops such as maize. Climate change is predicted to have different effects in different Southern Africa regions, as the climate in the southern African region constitutes an arid western region and a sub-humid eastern region. Cultivar selection is very important as cultivars are developed based on the climatic conditions of the regions within which they will be grown. Results from free-air CO2 enrichment experiments in the Northern hemisphere conducted at 550 ppm have shown that C4 crops such as maize benefit from eCO2 only in the presence of environmental stressors such as drought. Studies done on eCO2 and drought have a great geographical bias as they have predominantly been performed in temperate, northern hemisphere climates. This is an issue since the effect of elevated CO2 varies with climate, it is necessary to address this by including data representative of warmer and more arid climates. Although CO2 concentration changes are uniform across the globe, the way crops respond to elevated CO2 depends on the prevailing environmental and climatic conditions in the region. The study's objective was to determine the effects of elevated CO2 and drought on the growth, yield and grain quality of South African maize cultivars bred for the semi-arid western and sub-humid eastern production regions. , Thesis (MSc) -- Faculty of Science, Botany, 2021
- Full Text:
- Date Issued: 2021-10
Evaluation of Megabruchidius tonkineus (Coleoptera: Chrysomelidae: Bruchinae), a candidate biological control agent for Gleditsia triacanthos L. (Fabaceae) in South Africa
- Salgado Astudillo, Sara Elizabeth
- Authors: Salgado Astudillo, Sara Elizabeth
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/188386 , vital:44749
- Description: Gleditsia triacanthos L. (Fabaceae) (honey locust) is a fast-growing, deciduous tree indigenous to the United States of America. Introduced around the world as an ornamental tree, it has become invasive in a number of countries. Where it is invasive, G. triacanthos competes and replaces indigenous species; it creates dense stands along watercourses, posing a significant environmental threat. In South Africa, G. triacanthos is regarded as one of the country’s fastest spreading weeds. Gleditsia triacanthos produces numerous seeds contained in large hanging pods. Once dislodged from the pods, the seeds are dispersed by birds and mammals, including livestock, which eat the pods. It has been suggested that the seeds should be the target for biological control programme. Some invasive alien plant species are characterised by their ability to spread and establish in new ecosystems because they tolerate a wide range of environmental conditions. In order to predict areas of likely invasion, species distribution models (SDMs) are used to identify areas climatically suitable for their invasion, so enabling better targeted control of the plant species. Gleditsia triacanthos adapts to a wide range of climates and soil types, and tolerates salinity, drought and frost. Currently primarily restricted to the Grassland Biome of South Africa, G. triacanthos has doubled its distribution area in the past 15 years, and it is not known how far the species will spread. In this study we used two different modelling programmes, CLIMEX and MaxEnt, to predict areas where G. triacanthos could find favourable growing conditions; both SDMs showed that most of the country is suitable for G. triacanthos and that it will probably continue to spread, if left unmanaged, into new bioregions, such as the Karoo. In South Africa, the Asian seed-feeding bruchid, Megabruchidius tonkineus (Pic, 1914) (Coleoptera: Chrysomelidae: Bruchinae) has been recorded in the plant’s seed pods and has been considered as a biological control agent. The insect was not released as part of a formal biological control programme and neither host-specificity nor impact studies were conducted on the species prior to its discovery. In 2017 a decision was made to re-consider its status as a Abstract biological control agent until further details of its biology, host specificity, and impact on the seeds of G. triacanthos in South Africa were available. This study shows that Megabruchidius tonkineus has established across the entire G. triacanthos population in South Africa damaging approximately 9% of seeds. Laboratory studies show that, Megabruchidius tonkineus completes its larval development in the seeds of G. triacanthos in about 66.80 ± 0.6880 SE days before eclosing. In addition, the adult females oviposit on the following Fabaceae species: Arachis hypogaea, Albizia, julibrissin, Cicer arietinum, Pisum sativum, Dipogon lignosus, Peltophorum africanum, Podalyria buxifolia Senegalia burkei, Umtiza listerina and Vachellia sieberiana. However, larval development was limited to G. triacanthos. It is concluded that the seed-feeding beetle is not a threat to native Fabaceae species in South Africa, however, it does not damage enough G. triacanthos seeds to be considered a valuable biological control agent at this stage, and additional seed-feeding biological control agents should be considered to reduce the number of G. triacanthos seeds entering the environment. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Salgado Astudillo, Sara Elizabeth
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/188386 , vital:44749
- Description: Gleditsia triacanthos L. (Fabaceae) (honey locust) is a fast-growing, deciduous tree indigenous to the United States of America. Introduced around the world as an ornamental tree, it has become invasive in a number of countries. Where it is invasive, G. triacanthos competes and replaces indigenous species; it creates dense stands along watercourses, posing a significant environmental threat. In South Africa, G. triacanthos is regarded as one of the country’s fastest spreading weeds. Gleditsia triacanthos produces numerous seeds contained in large hanging pods. Once dislodged from the pods, the seeds are dispersed by birds and mammals, including livestock, which eat the pods. It has been suggested that the seeds should be the target for biological control programme. Some invasive alien plant species are characterised by their ability to spread and establish in new ecosystems because they tolerate a wide range of environmental conditions. In order to predict areas of likely invasion, species distribution models (SDMs) are used to identify areas climatically suitable for their invasion, so enabling better targeted control of the plant species. Gleditsia triacanthos adapts to a wide range of climates and soil types, and tolerates salinity, drought and frost. Currently primarily restricted to the Grassland Biome of South Africa, G. triacanthos has doubled its distribution area in the past 15 years, and it is not known how far the species will spread. In this study we used two different modelling programmes, CLIMEX and MaxEnt, to predict areas where G. triacanthos could find favourable growing conditions; both SDMs showed that most of the country is suitable for G. triacanthos and that it will probably continue to spread, if left unmanaged, into new bioregions, such as the Karoo. In South Africa, the Asian seed-feeding bruchid, Megabruchidius tonkineus (Pic, 1914) (Coleoptera: Chrysomelidae: Bruchinae) has been recorded in the plant’s seed pods and has been considered as a biological control agent. The insect was not released as part of a formal biological control programme and neither host-specificity nor impact studies were conducted on the species prior to its discovery. In 2017 a decision was made to re-consider its status as a Abstract biological control agent until further details of its biology, host specificity, and impact on the seeds of G. triacanthos in South Africa were available. This study shows that Megabruchidius tonkineus has established across the entire G. triacanthos population in South Africa damaging approximately 9% of seeds. Laboratory studies show that, Megabruchidius tonkineus completes its larval development in the seeds of G. triacanthos in about 66.80 ± 0.6880 SE days before eclosing. In addition, the adult females oviposit on the following Fabaceae species: Arachis hypogaea, Albizia, julibrissin, Cicer arietinum, Pisum sativum, Dipogon lignosus, Peltophorum africanum, Podalyria buxifolia Senegalia burkei, Umtiza listerina and Vachellia sieberiana. However, larval development was limited to G. triacanthos. It is concluded that the seed-feeding beetle is not a threat to native Fabaceae species in South Africa, however, it does not damage enough G. triacanthos seeds to be considered a valuable biological control agent at this stage, and additional seed-feeding biological control agents should be considered to reduce the number of G. triacanthos seeds entering the environment. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-10
Nurturing an identity of land custodianship of young people through a biodiversity learning programme: The Moletele Youth Learning Programme
- Authors: Mponwana, William Oupa
- Date: 2021-10
- Subjects: Sustainable biodiversity South Africa Mopani District Municipality , Association for Water and Rural Development (South Africa) , Land reform beneficiaries South Africa Mopani District Municipality , Agricultural development projects South Africa Mopani District Municipality , Land use Study and teaching South Africa Mopani District Municipality , Identity (Psychology) Social aspects South Africa Mopani District Municipality , Identity (Psychology) in youth South Africa Mopani District Municipality , Moletele Youth Learning Programme , Moletele Communal Property Association (CPA) , RESILIM-O
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188820 , vital:44789
- Description: This study was an exploration of value creation through scaffolding in a context specific learning programme with young people within the Moletele Communal Property Association (CPA) who own land through the land reform programme in South Africa. The study aimed to support the development the identity of land custodianship amongst young people by developing their skills and competencies in a situated learning context. The study also informed ongoing support work through the RESILIM-O resilience building project implemented by the Association for Water and Rural Development (AWARD) to help the Moletele Community Property Association to better understand the implications of biodiversity and land use for developing sustainable beneficiation projects and planning. A case study approach was adopted through a learning programme with young people as an in-depth exploration of the complexities of land and biodiversity. Data were collected during sessions in the learning programme where we used a spiral framework to facilitate learning focusing on four themes for primary data: knowledge competence, technical skills, self-organization and collective agency which are linked to building an identity of custodianship. Semi structured interviews were conducted at the end of the learning programme as a secondary data source. The study found that scaffolding remained an important process throughout the learning programme, and different types of scaffolding was needed to support the learning processes and themes. Furthermore, different types of value were created over time through the interactions and activities of the learning programme. The study also found that young people have a desire to participate in their communal property association. Lastly the study revealed that building custodianship as an identity is a continuous, long term process that needs commitment of time, resources and supportive learning processes, for an identity of custodianship to emerge. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Mponwana, William Oupa
- Date: 2021-10
- Subjects: Sustainable biodiversity South Africa Mopani District Municipality , Association for Water and Rural Development (South Africa) , Land reform beneficiaries South Africa Mopani District Municipality , Agricultural development projects South Africa Mopani District Municipality , Land use Study and teaching South Africa Mopani District Municipality , Identity (Psychology) Social aspects South Africa Mopani District Municipality , Identity (Psychology) in youth South Africa Mopani District Municipality , Moletele Youth Learning Programme , Moletele Communal Property Association (CPA) , RESILIM-O
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188820 , vital:44789
- Description: This study was an exploration of value creation through scaffolding in a context specific learning programme with young people within the Moletele Communal Property Association (CPA) who own land through the land reform programme in South Africa. The study aimed to support the development the identity of land custodianship amongst young people by developing their skills and competencies in a situated learning context. The study also informed ongoing support work through the RESILIM-O resilience building project implemented by the Association for Water and Rural Development (AWARD) to help the Moletele Community Property Association to better understand the implications of biodiversity and land use for developing sustainable beneficiation projects and planning. A case study approach was adopted through a learning programme with young people as an in-depth exploration of the complexities of land and biodiversity. Data were collected during sessions in the learning programme where we used a spiral framework to facilitate learning focusing on four themes for primary data: knowledge competence, technical skills, self-organization and collective agency which are linked to building an identity of custodianship. Semi structured interviews were conducted at the end of the learning programme as a secondary data source. The study found that scaffolding remained an important process throughout the learning programme, and different types of scaffolding was needed to support the learning processes and themes. Furthermore, different types of value were created over time through the interactions and activities of the learning programme. The study also found that young people have a desire to participate in their communal property association. Lastly the study revealed that building custodianship as an identity is a continuous, long term process that needs commitment of time, resources and supportive learning processes, for an identity of custodianship to emerge. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-10
Physiological winners and losers in an ocean warming hotspot: a Case study on argyrosomus off the Namibian coast, with implications for their future management
- Authors: Pringle, Brett Andrew
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188987 , vital:44804
- Description: Anthropogenic-induced climate change is having a profound impact on aquatic ecosystems, and the resilience of fish populations will be determined by how they respond to these impacts. Changes in ocean water temperature is regarded as the most pervasive change, and affects the biological, physiological and distribution response of species, particularly ectotherms. The increasingly variable biological responses to a changing environment suggest that some species and populations will likely prove to be more tolerant than others. The northern Namibian coast is an ocean warming hotspot, with temperatures rising at approximately ten times the global average. These rapid changes are predicted to have a considerable impact on the marine fauna. One recently documented change in distribution is a southern extension of the sciaenid, Argyrosomus coronus, from southern Angola into northern Namibian waters, where it now overlaps with the closely related Namibian species, Argyrosomus inodorus. Understanding how these species perform at current and future temperatures and where they overlap is vital to optimise any adaptive management for the Argyrosomus species, which forms a large component of Namibia’s coastal commercial, recreational and subsistence fisheries. The aim of this study was to quantify the aerobic scope of both species (A. coronus and A. inodorus), to determine which Argyrosomus species will be a winner at the current and future climate predictions and to provide recommendations for the sustainable management of the Namibian Argyrosomus fishery. Intermittent flow-through respirometry was used to quantify standard and maximum metabolic rates for both species across a range of temperatures. Results showed that metabolic rates scaled positively with temperature. It appears that the aerobic scope of A. inodorus was notably higher at most temperatures (12, 15, 18 and 21˚C), while that of A. coronus was only higher at the warmest test temperature of 24˚C. This corresponded with the contemporary biogeographic patterns of each species. Based on these findings, it is likely that the warming ocean conditions in northern Namibia and the cold Lüdertiz upwelling cell south of Walvis Bay will constrain these fish to central Namibia. While both species demonstrated signs of resilience to high temperatures, it is likely that the warming conditions will increasingly favour A. coronus, and that the leading edge of their distribution will shift southward in Namibia. The distribution of A. inodorus is likely to contract, as the energy budget of those on the northern trailing edge will be compromised. To promote the sustainable utilisation of the complex Argyrosomus fishery, adaptive management strategies need to be implemented. This will only be possible with a comprehensive monitoring program, including the collection of genetic data to inform the changing proportions of the two species. To maintain the A. coronus population, the current regulations need to be re-assessed, and harvest slots should be introduced to protect juvenile A. coronus and the fecund large females of both species. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Pringle, Brett Andrew
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188987 , vital:44804
- Description: Anthropogenic-induced climate change is having a profound impact on aquatic ecosystems, and the resilience of fish populations will be determined by how they respond to these impacts. Changes in ocean water temperature is regarded as the most pervasive change, and affects the biological, physiological and distribution response of species, particularly ectotherms. The increasingly variable biological responses to a changing environment suggest that some species and populations will likely prove to be more tolerant than others. The northern Namibian coast is an ocean warming hotspot, with temperatures rising at approximately ten times the global average. These rapid changes are predicted to have a considerable impact on the marine fauna. One recently documented change in distribution is a southern extension of the sciaenid, Argyrosomus coronus, from southern Angola into northern Namibian waters, where it now overlaps with the closely related Namibian species, Argyrosomus inodorus. Understanding how these species perform at current and future temperatures and where they overlap is vital to optimise any adaptive management for the Argyrosomus species, which forms a large component of Namibia’s coastal commercial, recreational and subsistence fisheries. The aim of this study was to quantify the aerobic scope of both species (A. coronus and A. inodorus), to determine which Argyrosomus species will be a winner at the current and future climate predictions and to provide recommendations for the sustainable management of the Namibian Argyrosomus fishery. Intermittent flow-through respirometry was used to quantify standard and maximum metabolic rates for both species across a range of temperatures. Results showed that metabolic rates scaled positively with temperature. It appears that the aerobic scope of A. inodorus was notably higher at most temperatures (12, 15, 18 and 21˚C), while that of A. coronus was only higher at the warmest test temperature of 24˚C. This corresponded with the contemporary biogeographic patterns of each species. Based on these findings, it is likely that the warming ocean conditions in northern Namibia and the cold Lüdertiz upwelling cell south of Walvis Bay will constrain these fish to central Namibia. While both species demonstrated signs of resilience to high temperatures, it is likely that the warming conditions will increasingly favour A. coronus, and that the leading edge of their distribution will shift southward in Namibia. The distribution of A. inodorus is likely to contract, as the energy budget of those on the northern trailing edge will be compromised. To promote the sustainable utilisation of the complex Argyrosomus fishery, adaptive management strategies need to be implemented. This will only be possible with a comprehensive monitoring program, including the collection of genetic data to inform the changing proportions of the two species. To maintain the A. coronus population, the current regulations need to be re-assessed, and harvest slots should be introduced to protect juvenile A. coronus and the fecund large females of both species. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries, 2021
- Full Text:
- Date Issued: 2021-10
Potential of the Gravel Filter Towers, Pilot-scale Filter system and Biochar/Clay adsorbents for Bio-Physicochemical remediation and Desalination of greywater
- Authors: Bani, Siphumze
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/188375 , vital:44748
- Description: Thesis embargoed until 2023 , Thesis (MSc) -- Faculty of Science, Rhodes University Biotechnology Innovation Centre, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Bani, Siphumze
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/188375 , vital:44748
- Description: Thesis embargoed until 2023 , Thesis (MSc) -- Faculty of Science, Rhodes University Biotechnology Innovation Centre, 2021
- Full Text:
- Date Issued: 2021-10
Potential Synergism between Entomopathogenic Fungi and Entomopathogenic Nematodes for the control of false codling moth (Thaumatotibia leucotreta)
- Authors: Prinsloo, Samantha Lee
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188832 , vital:44790
- Description: False codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) (FCM), is a major phytosanitary pest of citrus in South Africa. Sufficient control measures for the soil-dwelling life stages of FCM have yet to be identified and owing to restrictions on the use of insecticides, non-chemical control options have been investigated including the use of entomopathogenic fungi (EPF) and entomopathogenic nematodes (EPN). Laboratory and field trials on an indigenous EPF, Metarhizium anisopliae FCM Ar 23 B3, have shown that this isolate is capable of inducing mortality in FCM soil-dwelling life stages. Other agents that have been highlighted as potential controls for soil-dwelling FCM life stages are the EPN species Steinernema yirgalemense 157-C, S. jeffreyense J194 and H. noenieputensis 158-C. This study conducted laboratory bioassays to assess the virulence of these four control agents on fifth instar FCM, in 24-well plates. These results reaffirmed the virulence of the four microbial control agents at their recommended doses of 50 IJs (EPN) and 1×107 conidia/ml (EPF) against fifth instar FCM with 80 to 96% larval mortality recorded. The EPF isolate exhibited the lowest mortality whilst S. yirgalemense induced the greatest mortality. In addition, the lethal concentration (LC) values for each isolate were determined using dose response bioassays. These values were previously unknown for all EPN species and for the EPF isolate based on the methodology used in this study. The LC50 results in order from lowest to highest EPN IJ concentration requirements were 4.38 IJs (S. yirgalemense), 4.47 IJs (S. jeffreyense) and 7.11 IJs (H. noenieputensis). The EPF isolate exhibited an LC50 of 3.42×105 conidia/ml. Lastly, research has shown that the combination of two control agents may increase control of late instar lepidopteran and coleopteran larvae, through synergistic interactions. Thus, the interactions that occurred between the combination of these EPN species with the EPF isolate were determined. This study found that when all three EPN species were combined simultaneously and sequentially with the EPF isolate M. anisopliae FCM AR 23 B3, additive interactions took place with exception of the simultaneous application of S. yirgalemense and H. noenieputensis, with the EPF and S. jeffreyense applied 24 h post EPF application. For the former, a synergistic interaction was found, whilst for the latter two, an antagonistic interaction. Although no strongly synergistic interactions were observed, additive interactions have been shown to reach a synergistic level when certain parameters are changed. Moving forward, a uniform methodology for conducting EPF/EPN interaction experiments has been suggested. It has also been recommended that due to the additive interactions observed in this study, laboratory soil-bioassays and field trials should be carried out for all three EPN species in combination with the EPF isolate. This research will inevitably facilitate the constant knowledge into management strategies for the phytosanitary pest, FCM in South African citrus. , Thesis (MSc) -- Science, Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Prinsloo, Samantha Lee
- Date: 2021-10
- Subjects: Uncatalogued
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188832 , vital:44790
- Description: False codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) (FCM), is a major phytosanitary pest of citrus in South Africa. Sufficient control measures for the soil-dwelling life stages of FCM have yet to be identified and owing to restrictions on the use of insecticides, non-chemical control options have been investigated including the use of entomopathogenic fungi (EPF) and entomopathogenic nematodes (EPN). Laboratory and field trials on an indigenous EPF, Metarhizium anisopliae FCM Ar 23 B3, have shown that this isolate is capable of inducing mortality in FCM soil-dwelling life stages. Other agents that have been highlighted as potential controls for soil-dwelling FCM life stages are the EPN species Steinernema yirgalemense 157-C, S. jeffreyense J194 and H. noenieputensis 158-C. This study conducted laboratory bioassays to assess the virulence of these four control agents on fifth instar FCM, in 24-well plates. These results reaffirmed the virulence of the four microbial control agents at their recommended doses of 50 IJs (EPN) and 1×107 conidia/ml (EPF) against fifth instar FCM with 80 to 96% larval mortality recorded. The EPF isolate exhibited the lowest mortality whilst S. yirgalemense induced the greatest mortality. In addition, the lethal concentration (LC) values for each isolate were determined using dose response bioassays. These values were previously unknown for all EPN species and for the EPF isolate based on the methodology used in this study. The LC50 results in order from lowest to highest EPN IJ concentration requirements were 4.38 IJs (S. yirgalemense), 4.47 IJs (S. jeffreyense) and 7.11 IJs (H. noenieputensis). The EPF isolate exhibited an LC50 of 3.42×105 conidia/ml. Lastly, research has shown that the combination of two control agents may increase control of late instar lepidopteran and coleopteran larvae, through synergistic interactions. Thus, the interactions that occurred between the combination of these EPN species with the EPF isolate were determined. This study found that when all three EPN species were combined simultaneously and sequentially with the EPF isolate M. anisopliae FCM AR 23 B3, additive interactions took place with exception of the simultaneous application of S. yirgalemense and H. noenieputensis, with the EPF and S. jeffreyense applied 24 h post EPF application. For the former, a synergistic interaction was found, whilst for the latter two, an antagonistic interaction. Although no strongly synergistic interactions were observed, additive interactions have been shown to reach a synergistic level when certain parameters are changed. Moving forward, a uniform methodology for conducting EPF/EPN interaction experiments has been suggested. It has also been recommended that due to the additive interactions observed in this study, laboratory soil-bioassays and field trials should be carried out for all three EPN species in combination with the EPF isolate. This research will inevitably facilitate the constant knowledge into management strategies for the phytosanitary pest, FCM in South African citrus. , Thesis (MSc) -- Science, Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-10
Practicing conciliation: Towards a practical application of the Equal Weight View
- Authors: Hartley, Danyel Jordan
- Date: 2021-10
- Subjects: Knowledge, Theory of , Opinion (Philosophy) , Verbal self-defense , Epistemics , Interpersonal relations , Equal Weight View
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/188341 , vital:44745
- Description: The Equal Weight View is a frequently discussed position in the philosophy of disagreement. It holds that when someone disagrees with an epistemic peer, they should adjust their belief to be closer to their peer’s belief. While the reasons for adopting this response to disagreement have been debated, there has been less discussion about its utility as a tool for handling real-world disagreements. In this thesis I pursue a version of the Equal Weight View which is useful in practice. I argue that traditional applications of the Equal Weight View do not reflect its underlying principles when they are used to resolve real-world disagreements. I develop an idealized application of the Equal Weight View that addresses the problems traditional applications face in real-world scenarios. Unfortunately, addressing these problems results in an application that is unrealistically cognitively demanding. The application trades being insensitive to the environment it would be used in for being insensitive to the limits of its user. I suggest that we might be able to save the idealized application and work around those limits by either externalizing or simplifying the most demanding aspects of the application. Externalization is best achieved by making use of some kind of computer assistance. Simplification involves replacing taxing data tracking and computation with heuristic methods. While neither approach is ideal, I argue that both get us closer to resolving disagreements in accordance with the underlying principles of the Equal Weight View than traditional applications do. , Thesis (MA) -- Faculty of Humanities, Philosophy, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Hartley, Danyel Jordan
- Date: 2021-10
- Subjects: Knowledge, Theory of , Opinion (Philosophy) , Verbal self-defense , Epistemics , Interpersonal relations , Equal Weight View
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/188341 , vital:44745
- Description: The Equal Weight View is a frequently discussed position in the philosophy of disagreement. It holds that when someone disagrees with an epistemic peer, they should adjust their belief to be closer to their peer’s belief. While the reasons for adopting this response to disagreement have been debated, there has been less discussion about its utility as a tool for handling real-world disagreements. In this thesis I pursue a version of the Equal Weight View which is useful in practice. I argue that traditional applications of the Equal Weight View do not reflect its underlying principles when they are used to resolve real-world disagreements. I develop an idealized application of the Equal Weight View that addresses the problems traditional applications face in real-world scenarios. Unfortunately, addressing these problems results in an application that is unrealistically cognitively demanding. The application trades being insensitive to the environment it would be used in for being insensitive to the limits of its user. I suggest that we might be able to save the idealized application and work around those limits by either externalizing or simplifying the most demanding aspects of the application. Externalization is best achieved by making use of some kind of computer assistance. Simplification involves replacing taxing data tracking and computation with heuristic methods. While neither approach is ideal, I argue that both get us closer to resolving disagreements in accordance with the underlying principles of the Equal Weight View than traditional applications do. , Thesis (MA) -- Faculty of Humanities, Philosophy, 2021
- Full Text:
- Date Issued: 2021-10
Quantifying the ecological and socioeconomic implications of a recovery/collapse of South Africa’s West Coast rock lobster fishery
- Authors: Eggers, Jessica Marguerite
- Date: 2021-10
- Subjects: Jasus lalandii South Africa , Lobster fisheries South Africa , Lobster fisheries Catch effort South Africa , Fishery management South Africa , Small-scale fisheries South Africa , Economics Sociological aspects , Value chain analysis
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188854 , vital:44792
- Description: The West Coast rock lobster (WCRL) Jasus lalandii fishery is South Africa’s third most valuable fishery, but the stock is currently at less than 2% of its pristine biomass. Scientists are warning that if no measures are taken, the WCRL could face commercial extinction. The necessary reductions in the global Total allowable Catch (TAC) seen in past years have had large economic implications for the WCRL value chain, but research into the socio-economic aspects of this fishery is limited. This study, therefore, aims to establish an overview of the economic revenue over the seasons 2016/17 – 2018/19 by exploring changes and trends in the net seasonal income (NSI) for the fishery, sectors within the fishery and different stakeholders. It also investigates the prospects for the sectors and different actors in this fishery over the seasons 2019/2020 - 2030/31 through analysis of the net present value (NPV) under three proposed global TAC management scenarios (global TAC of 640 tonnes, 1084 tonnes and 1280 tonnes). Data concerning costs and incomes as well as dynamics, mechanisms and concerns surrounding the fishery were collected from stakeholders in the different sectors through interviews and surveys. Further, official records from DEFF (catches, actors, vessels and quotas) and projections made by the Marine Resource Assessment (MARAM) team at the University of Cape Town (rates of recovery of the resource and future catches under the different TAC scenarios) were obtained and analysed. Cost and income data were summarised and models characterising the economic flows within the fishery were created. Calculations regarding the NSI and NPV were made using Monte Carlo simulations to account for the uncertainty surrounding many of the input variables. Results show that while the fishery as a whole made economic profits for the three seasons, the decreasing quotas in 2018/19 had a disproportionately negative impact on some of the representative individuals examined within the different sectors. The projections indicate that while each of the sectors as a whole would continue to make profits largely proportional to their allocation under the different TAC scenarios, many vessel owners in the fishery are likely to face economic losses or very marginal gains under the lower quota options, while the NPV for quota holders who outsource the catching of their quota are likely to be proportionally less affected by the changes in global TAC. This dynamic is important to consider for the future of this fishery. If the resource is to recover, and fishing activity is to continue equitably under the decreased quotas that the recovery of the biomass necessitates, the socio-economic context and the dynamics within which the fishers operate must be considered and studied more extensively and socio-economic consequences of a lower global TAC mitigated while improving the ecological status of the resource. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Eggers, Jessica Marguerite
- Date: 2021-10
- Subjects: Jasus lalandii South Africa , Lobster fisheries South Africa , Lobster fisheries Catch effort South Africa , Fishery management South Africa , Small-scale fisheries South Africa , Economics Sociological aspects , Value chain analysis
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188854 , vital:44792
- Description: The West Coast rock lobster (WCRL) Jasus lalandii fishery is South Africa’s third most valuable fishery, but the stock is currently at less than 2% of its pristine biomass. Scientists are warning that if no measures are taken, the WCRL could face commercial extinction. The necessary reductions in the global Total allowable Catch (TAC) seen in past years have had large economic implications for the WCRL value chain, but research into the socio-economic aspects of this fishery is limited. This study, therefore, aims to establish an overview of the economic revenue over the seasons 2016/17 – 2018/19 by exploring changes and trends in the net seasonal income (NSI) for the fishery, sectors within the fishery and different stakeholders. It also investigates the prospects for the sectors and different actors in this fishery over the seasons 2019/2020 - 2030/31 through analysis of the net present value (NPV) under three proposed global TAC management scenarios (global TAC of 640 tonnes, 1084 tonnes and 1280 tonnes). Data concerning costs and incomes as well as dynamics, mechanisms and concerns surrounding the fishery were collected from stakeholders in the different sectors through interviews and surveys. Further, official records from DEFF (catches, actors, vessels and quotas) and projections made by the Marine Resource Assessment (MARAM) team at the University of Cape Town (rates of recovery of the resource and future catches under the different TAC scenarios) were obtained and analysed. Cost and income data were summarised and models characterising the economic flows within the fishery were created. Calculations regarding the NSI and NPV were made using Monte Carlo simulations to account for the uncertainty surrounding many of the input variables. Results show that while the fishery as a whole made economic profits for the three seasons, the decreasing quotas in 2018/19 had a disproportionately negative impact on some of the representative individuals examined within the different sectors. The projections indicate that while each of the sectors as a whole would continue to make profits largely proportional to their allocation under the different TAC scenarios, many vessel owners in the fishery are likely to face economic losses or very marginal gains under the lower quota options, while the NPV for quota holders who outsource the catching of their quota are likely to be proportionally less affected by the changes in global TAC. This dynamic is important to consider for the future of this fishery. If the resource is to recover, and fishing activity is to continue equitably under the decreased quotas that the recovery of the biomass necessitates, the socio-economic context and the dynamics within which the fishers operate must be considered and studied more extensively and socio-economic consequences of a lower global TAC mitigated while improving the ecological status of the resource. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2021
- Full Text:
- Date Issued: 2021-10
Queer as Africa: Representations of queer lives in selected Nigerian, Kenyan, and South African literature and film
- Authors: Wilson, Jon Stephen Edward
- Date: 2021-10
- Subjects: Africans in literature , Africans in motion pictures , Homosexuality in literature , Homosexuality in motion pictures , Sexual minorities in literature , Sexual minorities in motion pictures , African literature History and criticism , Motion pictures, African History and criticism , Sexual minorities South Africa Public opinion , Sexual minorities Kenya Public opinion , Sexual minorities Nigeria Public opinion , Sexual minorities South Africa Social conditions , Sexual minorities Kenya Social conditions , Sexual minorities Nigeria Social conditions
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/187428 , vital:44651
- Description: This thesis contests the notion that nonnormative sexualities are ‘un-African’ by examining a range of representations of queer African lives on film and in literature, produced by Africans for Africans, as a means to interrogate the role played by the interconnected histories of colonialism, religion, and the policing of queer intimacy, specifically in Kenya, Nigeria, and South Africa. Through a close reading of a selection of texts from these three countries, this thesis takes a cultural-historical approach to exploring the complex struggles engaged in by queer people in Africa to protections under the law, and to represent themselves in literary and cinematic narratives. The first chapter is focused on the Kenyan film Rafiki (2018), directed by Wanuri Kahiu, which tells the story of queer love between two young Kenyan women who face the vehement condemnation of their relationship from their homophobic community. The film was banned in Kenya, but the director was granted a temporary injunction by Kenya’s high court in order for it to be screened in Nairobi. This made Rafiki the first queer film ever to be screened in Kenya, and viable for an Academy Award nomination. The second chapter focuses on the bold assertion of a queer African identity through the short story collections Queer Africa: New and Collected Fiction (2013) and Queer Africa 2: New Stories (2017). Written by various authors from the African continent, and compiled and edited by Karen Martin and Makhosazana Xaba, both collections offer a wide variety of fictional narratives focused on queer experiences in Africa. The second chapter has a focus on stories from Kenyan and Nigerian authors and explores notions of home, queer belonging, and visibility. The third chapter presents a close reading of the South African film Inxeba (2017), also known as The Wound, directed by John Trengove and adapted by Trengove and Thando Mgqolozana from Mgqolozana’s novel, A Man Who Is Not A Man (2009). The film depicts the traditional Xhosa initiation ritual, ulwaluko, and is set in the rural Eastern Cape. Inxeba is an important case study in the history of queer representation in Africa, as the film hit a nerve with many, interrogating what South Africans believe about culture, traditions, masculinity, and the right of artists to represent sacred ritual in art. This thesis pays attention to the historical entanglements between homophobia, imperialism, and Christianity – relationships that continue to affect the experiences of queer people in Africa and attitudes towards them and interrogates why queer individuals are still being left out of efforts towards creating a new normal in postcolonial Africa. This thesis suggests that increased visibility is a key aspect of queer activism in Africa – through the act of representation, sharing lived experiences, and telling queer stories. , Thesis (MA) -- Faculty of Humanities, Literary Studies in English, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Wilson, Jon Stephen Edward
- Date: 2021-10
- Subjects: Africans in literature , Africans in motion pictures , Homosexuality in literature , Homosexuality in motion pictures , Sexual minorities in literature , Sexual minorities in motion pictures , African literature History and criticism , Motion pictures, African History and criticism , Sexual minorities South Africa Public opinion , Sexual minorities Kenya Public opinion , Sexual minorities Nigeria Public opinion , Sexual minorities South Africa Social conditions , Sexual minorities Kenya Social conditions , Sexual minorities Nigeria Social conditions
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/187428 , vital:44651
- Description: This thesis contests the notion that nonnormative sexualities are ‘un-African’ by examining a range of representations of queer African lives on film and in literature, produced by Africans for Africans, as a means to interrogate the role played by the interconnected histories of colonialism, religion, and the policing of queer intimacy, specifically in Kenya, Nigeria, and South Africa. Through a close reading of a selection of texts from these three countries, this thesis takes a cultural-historical approach to exploring the complex struggles engaged in by queer people in Africa to protections under the law, and to represent themselves in literary and cinematic narratives. The first chapter is focused on the Kenyan film Rafiki (2018), directed by Wanuri Kahiu, which tells the story of queer love between two young Kenyan women who face the vehement condemnation of their relationship from their homophobic community. The film was banned in Kenya, but the director was granted a temporary injunction by Kenya’s high court in order for it to be screened in Nairobi. This made Rafiki the first queer film ever to be screened in Kenya, and viable for an Academy Award nomination. The second chapter focuses on the bold assertion of a queer African identity through the short story collections Queer Africa: New and Collected Fiction (2013) and Queer Africa 2: New Stories (2017). Written by various authors from the African continent, and compiled and edited by Karen Martin and Makhosazana Xaba, both collections offer a wide variety of fictional narratives focused on queer experiences in Africa. The second chapter has a focus on stories from Kenyan and Nigerian authors and explores notions of home, queer belonging, and visibility. The third chapter presents a close reading of the South African film Inxeba (2017), also known as The Wound, directed by John Trengove and adapted by Trengove and Thando Mgqolozana from Mgqolozana’s novel, A Man Who Is Not A Man (2009). The film depicts the traditional Xhosa initiation ritual, ulwaluko, and is set in the rural Eastern Cape. Inxeba is an important case study in the history of queer representation in Africa, as the film hit a nerve with many, interrogating what South Africans believe about culture, traditions, masculinity, and the right of artists to represent sacred ritual in art. This thesis pays attention to the historical entanglements between homophobia, imperialism, and Christianity – relationships that continue to affect the experiences of queer people in Africa and attitudes towards them and interrogates why queer individuals are still being left out of efforts towards creating a new normal in postcolonial Africa. This thesis suggests that increased visibility is a key aspect of queer activism in Africa – through the act of representation, sharing lived experiences, and telling queer stories. , Thesis (MA) -- Faculty of Humanities, Literary Studies in English, 2021
- Full Text:
- Date Issued: 2021-10
The construction of phthalocyanine- carbon nanoparticle conjugates for applications in photodynamic therapy and non-linear optics
- Matshitse, Refilwe Manyama Stephina
- Authors: Matshitse, Refilwe Manyama Stephina
- Date: 2021-10
- Subjects: Phthalocyanines , Nanodiamonds , Photochemotherapy , Nonlinear optics , Quantum dots
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/188397 , vital:44750 , 10.21504/10962/188397
- Description: The syntheses and characterization of symmetric and asymmetric Pcs functionalized at the peripheral position and sometimes positively charged are reported. The Pcs had either H2, zinc or silicon as central metals and have pyridyloxy, benzothiozole phenoxy, and respective cationic analogues as ring substituents. The Pcs were linked to carbon based nanoparticles such as graphene quantum dots, carbon dots, and detonation nanodiamonds (DNDs) via an ester, amide bond and/or π - π stacking. The physicochemical characteristics of the Pcs were assessed when alone and when in a conjugated system. Both symmetrically and asymmetrically substituted benzothiozole Pcs when quaternised displayed higher triplet and singlet oxygen quantum yields than their unquaternised counterparts. Linkage to carbon nanoparticles (especially to detonation nanodiamonds) had an increasing effect on triplet and singlet oxygen quantum yield. However, a general decrease in singlet oxygen quantum yield on linkage to doped detonation nanodiamonds was associated with the screening effect of DNDs. Heteroatom doped DNDs-Pc nanohybrids have less singlet oxygen than Pcs alone due to molecular structural stability associated with strain that is relatively reduced upon linking Pcs. The In vitro dark cytotoxicity and photodynamic therapy of selected Pc complexes and conjugates against MCF-7 cells was tested. All studied Pc complexes and conjugates showed minimum dark toxicity making them applicable for PDT. When Pc complexes are alone, there is less phototoxicity with >22% cell viability at concentrations ≤ 50 μg/mL relative to conjugates with <22% cell viability at concentrations ≤ 50 μg/mL. There was no direct relationship between PDT and singlet oxygen quantum yields. Nonlinear optical characteristics of complexes was improved upon conjugation of DNDs. Absorbance, input energy, percentage loading, central metal, substituent of Pc and nature of interaction (covalent, noncovalent) are amongst some of the factors that influence nonlinear absorption properties of materials used in this study. All materials followed reverse saturable absorption through two photon absorption mechanism at the excitation wavelength of 532 nm. Aggregates reduce excited state lifetime and Beff under high concentrations/absorbance. A direct relationship between absorbance and Beff of DNDs nanoconjugated systems at low concentrations result in increased optical limiting characteristics of materials. The findings from this work show the importance of linking (nonlinear optics and photodynamic therapy) and doping (photodynamic therapy) photosensitisers such as phthalocyanines and sometimes boron dipyrromethenes onto carbon based nanoparticles for the enhanced characteristics in variable applications. , Thesis (PhD) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Matshitse, Refilwe Manyama Stephina
- Date: 2021-10
- Subjects: Phthalocyanines , Nanodiamonds , Photochemotherapy , Nonlinear optics , Quantum dots
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/188397 , vital:44750 , 10.21504/10962/188397
- Description: The syntheses and characterization of symmetric and asymmetric Pcs functionalized at the peripheral position and sometimes positively charged are reported. The Pcs had either H2, zinc or silicon as central metals and have pyridyloxy, benzothiozole phenoxy, and respective cationic analogues as ring substituents. The Pcs were linked to carbon based nanoparticles such as graphene quantum dots, carbon dots, and detonation nanodiamonds (DNDs) via an ester, amide bond and/or π - π stacking. The physicochemical characteristics of the Pcs were assessed when alone and when in a conjugated system. Both symmetrically and asymmetrically substituted benzothiozole Pcs when quaternised displayed higher triplet and singlet oxygen quantum yields than their unquaternised counterparts. Linkage to carbon nanoparticles (especially to detonation nanodiamonds) had an increasing effect on triplet and singlet oxygen quantum yield. However, a general decrease in singlet oxygen quantum yield on linkage to doped detonation nanodiamonds was associated with the screening effect of DNDs. Heteroatom doped DNDs-Pc nanohybrids have less singlet oxygen than Pcs alone due to molecular structural stability associated with strain that is relatively reduced upon linking Pcs. The In vitro dark cytotoxicity and photodynamic therapy of selected Pc complexes and conjugates against MCF-7 cells was tested. All studied Pc complexes and conjugates showed minimum dark toxicity making them applicable for PDT. When Pc complexes are alone, there is less phototoxicity with >22% cell viability at concentrations ≤ 50 μg/mL relative to conjugates with <22% cell viability at concentrations ≤ 50 μg/mL. There was no direct relationship between PDT and singlet oxygen quantum yields. Nonlinear optical characteristics of complexes was improved upon conjugation of DNDs. Absorbance, input energy, percentage loading, central metal, substituent of Pc and nature of interaction (covalent, noncovalent) are amongst some of the factors that influence nonlinear absorption properties of materials used in this study. All materials followed reverse saturable absorption through two photon absorption mechanism at the excitation wavelength of 532 nm. Aggregates reduce excited state lifetime and Beff under high concentrations/absorbance. A direct relationship between absorbance and Beff of DNDs nanoconjugated systems at low concentrations result in increased optical limiting characteristics of materials. The findings from this work show the importance of linking (nonlinear optics and photodynamic therapy) and doping (photodynamic therapy) photosensitisers such as phthalocyanines and sometimes boron dipyrromethenes onto carbon based nanoparticles for the enhanced characteristics in variable applications. , Thesis (PhD) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10