Figuring the black femme fatale: analysing black womanhood in U-Carmen eKhayelitsha
- Authors: Waters-Maine, Leigh
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466117 , vital:76687
- Description: In this thesis, I investigate black womanhood in U-Carmen eKhayelitsha, a post-apartheid film opera. The aim of this research is to examine the representation of black women in this film opera, focusing largely on the lead character, U-Carmen. This thesis is driven by a form of intersectional feminism which is characterised by overlapping categories such as race, gender, class and sexual orientation (Crenshaw 1989). A growing number of scholars have written about the rise of South African operas (Roos 2012; André 2016; Gerber 2021) but have seldom focused on the multi-layered representation of black women, which is what this thesis aims to do. In reading this work, I argue that U-Carmen eKhayelitsa foregrounds U-Carmen as a black woman with a storyline that rejects essentialists portrayals of black women on opera stages. The film opera, I argue, figures a complex womanhood represented in voice, labour, motherhood, and death. It not only recognizes the marginalised, but it also offers a change to the perception of the gendering of the black female body. In this thesis, I employ textual analysis to consider the historical contexts of U-Carmen alongside its contemporary resonances and analyse the main female character in the opera and how she can enforce or change the narrative of the role of women in opera. , Thesis (MA) -- Faculty of Humanities, Music and Musicology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Waters-Maine, Leigh
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466117 , vital:76687
- Description: In this thesis, I investigate black womanhood in U-Carmen eKhayelitsha, a post-apartheid film opera. The aim of this research is to examine the representation of black women in this film opera, focusing largely on the lead character, U-Carmen. This thesis is driven by a form of intersectional feminism which is characterised by overlapping categories such as race, gender, class and sexual orientation (Crenshaw 1989). A growing number of scholars have written about the rise of South African operas (Roos 2012; André 2016; Gerber 2021) but have seldom focused on the multi-layered representation of black women, which is what this thesis aims to do. In reading this work, I argue that U-Carmen eKhayelitsa foregrounds U-Carmen as a black woman with a storyline that rejects essentialists portrayals of black women on opera stages. The film opera, I argue, figures a complex womanhood represented in voice, labour, motherhood, and death. It not only recognizes the marginalised, but it also offers a change to the perception of the gendering of the black female body. In this thesis, I employ textual analysis to consider the historical contexts of U-Carmen alongside its contemporary resonances and analyse the main female character in the opera and how she can enforce or change the narrative of the role of women in opera. , Thesis (MA) -- Faculty of Humanities, Music and Musicology, 2024
- Full Text:
- Date Issued: 2024-10-11
Fishery characteristics, genetic structure, population demography and value chain of Skipjack and Kawakawa exploited in coastal waters of the Western Indian Ocean
- Authors: Mzingirwa, Fatuma Ali
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466759 , vital:76776 , DOI https://doi.org/10.21504/10962/466759
- Description: Tuna represents a highly valuable global fishery, comprising 7.9% of the total 67.9 million metric tons (MT) of marine finfish catch. Among tuna species, Katsuwonus pelamis, skipjack and Euthynnus affinis, kawakawa are commercially important, particularly for artisanal fisheries. Skipjack is the most dominant tuna species globally, contributing over 60% to total tuna production. In the Indian Ocean (IO), skipjack catches approximately 420,000 MT annually. Kawakawa, the second most abundant neritic tuna in the IO, accounting for roughly 12% of neritic tuna landings, is primarily harvested by artisanal fleets, with annual catches of around 160,000 MT. While current assessments indicate that skipjack and kawakawa stocks in the IO are not overfished, maintaining their long-term health is crucial. This research addresses three key areas: genetic diversity, population structure, and connectivity of skipjack and kawakawa tuna in the Western Indian Ocean (WIO); size structure and reproductive characteristics of these species within the WIO; and the value chain of the Kenyan artisanal tuna fishery, focusing on skipjack and kawakawa. To achieve these objectives, skipjack and kawakawa samples were collected from Kenya, Tanzania, Mozambique, and South Africa. A non-random sampling approach was employed to obtain specimens and data from artisanal and recreational fisheries. Biological and genetic sampling were conducted concurrently. The economic value chain of the Kenyan artisanal tuna fishery was examined through questionnaires and catch data. This analysis focused on the socio-demographic profiles of key actors, the value chain structure, and associated economic benefits across four Kenyan landing sites. To investigate stock structure in WIO skipjack and kawakawa tuna, we employed tunable Genotyping-by-Sequencing (tGBS) to generate genome-wide Single Nucleotide Polymorphism (SNP) data. Skipjack analysis revealed 7005 SNPs with an average observed heterozygosity (Ho) of 0.206. While overall genetic differentiation (FST) among samples was low (global FST = 0.003) between samples (FST = 0 – 0.013), significant genetic differences were observed between skipjack samples taken north of Mtwara in southern Tanzania (i.e., northern Tanzania, Kenya and Sri Lanka) and those to the south (i.e., southern Tanzania, Mozambique and South Africa), with Seychelles falling closer to the southern grouping. Kawakawa analysis, based on 14806 SNPs and an average Ho of 0.2585, indicated a patchy distribution of low but significant genetic differentiation among WIO populations (global FST = 0.018) between-sample (FST = 0.003 – 0.036) but with no obvious geographically-based pattern. However, unlike skipjack, a clear geographic pattern in genetic structure was not evident for kawakawa. Skipjack and kawakawa populations in the WIO exhibited seasonal fluctuations in size distribution, potentially influenced by environmental conditions and fishing practices. Landings of both species were male-biased, with sex ratios of 58% and 53% for skipjack and kawakawa, respectively. Female skipjack reached sexual maturity at a fork length (FL) of 42.0 cm, while males matured at 47.0 cm FL. For kawakawa, female and male maturation lengths were 44.0 cm FL and 45.3 cm FL, respectively. Spawning occurred throughout the year, with peak activity coinciding with the Northeast Monsoon (NEM) season. Our analysis of the artisanal tuna value chain indicates that fishers primarily sell their catch to agents (53%), with the remaining proportions going to traders (20%) and processors (18%). Processors, predominantly women, play a key role in the value chain and realized the highest net profit margin (49.5%). Limited post-harvest infrastructure, inadequate transportation, and poor marketing conditions were identified as key challenges impacting the quality of fish lowering their income. These challenges disproportionately affect fishers with limited access to market information and financial resources. The findings demonstrate the need for multi-level interventions to optimize benefits from the artisanal tuna fishery along the entire value chain taking into consideration the economic, environmental, and social dimensions. This research provides crucial information for effective tuna management in the IO. Current management practices treat skipjack and kawakawa as a single, homogenous population across the entire IO. However, our genetic findings suggest the presence of distinct population groups (stocks) for both species within the WIO. Moreover, seasonal variations in size structure and reproductive characteristics observed support this hypothesis of multiple stocks. These results emphasize the need for a precautionary approach to tuna management in the region. Collaborative efforts among countries are essential to develop sustainable fisheries management strategies that consider biological, economic, and social factors. By integrating these perspectives, we can ensure the long-term health of tuna populations while supporting the livelihoods of fishing communities. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Mzingirwa, Fatuma Ali
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466759 , vital:76776 , DOI https://doi.org/10.21504/10962/466759
- Description: Tuna represents a highly valuable global fishery, comprising 7.9% of the total 67.9 million metric tons (MT) of marine finfish catch. Among tuna species, Katsuwonus pelamis, skipjack and Euthynnus affinis, kawakawa are commercially important, particularly for artisanal fisheries. Skipjack is the most dominant tuna species globally, contributing over 60% to total tuna production. In the Indian Ocean (IO), skipjack catches approximately 420,000 MT annually. Kawakawa, the second most abundant neritic tuna in the IO, accounting for roughly 12% of neritic tuna landings, is primarily harvested by artisanal fleets, with annual catches of around 160,000 MT. While current assessments indicate that skipjack and kawakawa stocks in the IO are not overfished, maintaining their long-term health is crucial. This research addresses three key areas: genetic diversity, population structure, and connectivity of skipjack and kawakawa tuna in the Western Indian Ocean (WIO); size structure and reproductive characteristics of these species within the WIO; and the value chain of the Kenyan artisanal tuna fishery, focusing on skipjack and kawakawa. To achieve these objectives, skipjack and kawakawa samples were collected from Kenya, Tanzania, Mozambique, and South Africa. A non-random sampling approach was employed to obtain specimens and data from artisanal and recreational fisheries. Biological and genetic sampling were conducted concurrently. The economic value chain of the Kenyan artisanal tuna fishery was examined through questionnaires and catch data. This analysis focused on the socio-demographic profiles of key actors, the value chain structure, and associated economic benefits across four Kenyan landing sites. To investigate stock structure in WIO skipjack and kawakawa tuna, we employed tunable Genotyping-by-Sequencing (tGBS) to generate genome-wide Single Nucleotide Polymorphism (SNP) data. Skipjack analysis revealed 7005 SNPs with an average observed heterozygosity (Ho) of 0.206. While overall genetic differentiation (FST) among samples was low (global FST = 0.003) between samples (FST = 0 – 0.013), significant genetic differences were observed between skipjack samples taken north of Mtwara in southern Tanzania (i.e., northern Tanzania, Kenya and Sri Lanka) and those to the south (i.e., southern Tanzania, Mozambique and South Africa), with Seychelles falling closer to the southern grouping. Kawakawa analysis, based on 14806 SNPs and an average Ho of 0.2585, indicated a patchy distribution of low but significant genetic differentiation among WIO populations (global FST = 0.018) between-sample (FST = 0.003 – 0.036) but with no obvious geographically-based pattern. However, unlike skipjack, a clear geographic pattern in genetic structure was not evident for kawakawa. Skipjack and kawakawa populations in the WIO exhibited seasonal fluctuations in size distribution, potentially influenced by environmental conditions and fishing practices. Landings of both species were male-biased, with sex ratios of 58% and 53% for skipjack and kawakawa, respectively. Female skipjack reached sexual maturity at a fork length (FL) of 42.0 cm, while males matured at 47.0 cm FL. For kawakawa, female and male maturation lengths were 44.0 cm FL and 45.3 cm FL, respectively. Spawning occurred throughout the year, with peak activity coinciding with the Northeast Monsoon (NEM) season. Our analysis of the artisanal tuna value chain indicates that fishers primarily sell their catch to agents (53%), with the remaining proportions going to traders (20%) and processors (18%). Processors, predominantly women, play a key role in the value chain and realized the highest net profit margin (49.5%). Limited post-harvest infrastructure, inadequate transportation, and poor marketing conditions were identified as key challenges impacting the quality of fish lowering their income. These challenges disproportionately affect fishers with limited access to market information and financial resources. The findings demonstrate the need for multi-level interventions to optimize benefits from the artisanal tuna fishery along the entire value chain taking into consideration the economic, environmental, and social dimensions. This research provides crucial information for effective tuna management in the IO. Current management practices treat skipjack and kawakawa as a single, homogenous population across the entire IO. However, our genetic findings suggest the presence of distinct population groups (stocks) for both species within the WIO. Moreover, seasonal variations in size structure and reproductive characteristics observed support this hypothesis of multiple stocks. These results emphasize the need for a precautionary approach to tuna management in the region. Collaborative efforts among countries are essential to develop sustainable fisheries management strategies that consider biological, economic, and social factors. By integrating these perspectives, we can ensure the long-term health of tuna populations while supporting the livelihoods of fishing communities. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2024
- Full Text:
- Date Issued: 2024-10-11
Foundation phase teachers’ understanding and implementation of differentiated pedagogical practices in teaching reading
- Authors: Muroa, Johanna Makgati
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463713 , vital:76434
- Description: Pre-1994, teacher education in South Africa was separated into mainstream and special education classes. Special education classes accommodated learners who were not coping with grade-level work. In 2001, Education White Paper Six advocated for inclusive education. This policy promotes differentiated pedagogical practices to accommodate learners’ needs and minimize barriers to learning. However, research has shown that teachers do not have the required content and pedagogical knowledge to teach according to diverse learners’ needs. One of the reasons given is that the teacher education system does not prepare teachers adequately to teach in classrooms with diverse learners. This qualitative case study is underpinned by an interpretivist orientation as it seeks to ascertain how teachers understand and implement differentiated pedagogical tools in their practice. The research asks the question: How do Foundation Phase teachers understand and implement differentiated pedagogical tools? Seventy-six teachers enrolled for in-service Bachelor of Education (Foundation Phase) completed a questionnaire and three Foundation Phase teachers were observed and interviewed. Data gathered was analyzed using the Theory of Practice Architectures. The study found that the teachers recognized the importance of accommodating the different learners’ learning needs, however, they struggled to implement differentiated pedagogical practices in the classroom. , Thesis (MEd) -- Faculty of Education, Primary and Early Childhood Education, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Muroa, Johanna Makgati
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463713 , vital:76434
- Description: Pre-1994, teacher education in South Africa was separated into mainstream and special education classes. Special education classes accommodated learners who were not coping with grade-level work. In 2001, Education White Paper Six advocated for inclusive education. This policy promotes differentiated pedagogical practices to accommodate learners’ needs and minimize barriers to learning. However, research has shown that teachers do not have the required content and pedagogical knowledge to teach according to diverse learners’ needs. One of the reasons given is that the teacher education system does not prepare teachers adequately to teach in classrooms with diverse learners. This qualitative case study is underpinned by an interpretivist orientation as it seeks to ascertain how teachers understand and implement differentiated pedagogical tools in their practice. The research asks the question: How do Foundation Phase teachers understand and implement differentiated pedagogical tools? Seventy-six teachers enrolled for in-service Bachelor of Education (Foundation Phase) completed a questionnaire and three Foundation Phase teachers were observed and interviewed. Data gathered was analyzed using the Theory of Practice Architectures. The study found that the teachers recognized the importance of accommodating the different learners’ learning needs, however, they struggled to implement differentiated pedagogical practices in the classroom. , Thesis (MEd) -- Faculty of Education, Primary and Early Childhood Education, 2024
- Full Text:
- Date Issued: 2024-10-11
Gold mineralization at the Blue Rock Deposit, Gadzema Greenstone Belt: Implications on genesis and exploration for orogenic gold mineralization within Archaean Greenstone Belts of Zimbabwe
- Authors: Mavuwa, Tavashavira
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464944 , vital:76559
- Description: The Blue Rock gold deposit was re-discovered by African Consolidated Resources (ACR) in 2007, over a defunct historical gold mine at Blue Rock, during a regional geochemical soil sampling program, within the Gadzema Greenstone Belt (GGB), in Central Zimbabwe. Most significant orogenic gold deposits within this belt occur as BIF- and quartz vein hosted orebodies. But unlike them, gold mineralization at Blue Rock is associated with felsite and quartz porphyry rocks. The GGB is a northern extension of the Midlands Greenstone Belt (MGB), where the common occurrence of mineralized felsites, in close association with major gold reefs within numerous gold mines is well documented. But no significant effort was directed towards their understanding or exploration in the past. They were never considered viable exploration targets for significant economic gold deposits, until recently. More attention was instead focused on high-grade BIF and quartz vein hosted gold, that dominate most orebodies exploited by numerous mines within the belt. At Blue Rock, ACR defined a significant JORC compliant felsite-hosted gold resource of close to a million ounces, which represents a brand new attractive open-pit mining opportunity. But the successful exploration for such type of mineralization, whose footprint is so different from the common ones previously mined within the GGB, no doubt, calls for a good understanding of this type of mineralization. Which makes felsite-hosted gold mineralization a prime candidate for research, based on a deposit whose discovery and development, I was fortunate to be part of during the past few years. In this contribution, the genesis, localization and economic significance of felsite-hosted gold mineralization is investigated, using the gold deposit at Blue Rock as a case study. The deposit could be understood best through the Mineral Systems Approach, used in this study to interrogate alternative ideas about its genesis using published information and deposit-scale exploratory data. Results from the synthesis of published information on the evolution of Archaean Greenstone Belts and genesis of their host orogenic gold deposits, are consistent with models that view orogenic terrains as having formed through horizontal accretion in modern-day like subduction-accretion systems, at continental margins, where orogenic gold deposition occurred via processes that could be explained quite simply, through a universal orogenic gold mineral systems model. According to this model, orogenic gold deposits are believed to have formed from near neutral fluids containing dissolved gold, generated directly from the devolatilization of a subducted oceanic slab together with its overlying gold-bearing sulphide-rich sedimentary package, or indirectly through fluid released from a mantle lithosphere that was originally metasomatized and fertilized during an earlier subduction event. The fluid migrated up-dip from the mantle to crustal levels, through advection or seismic pumping along lithosphere- to crustal-scale fault zones, to form orogenic gold deposits within lower order structures. If these models are all accurate, then the GGB formed through subduction-related east-directed horizontal accretion at the continental margins of the Sebakwe Proto-Craton (SPC), and the genesis of felsite-hosted gold mineralization at Blue Rock could be explained eloquently through a universal orogenic gold model, in which mantle derived auriferous fluids were localised within lower order structures associated with felsites during the late stages of terrain accretion. Evidence from surface mapping and 3D modelling of exploratory drilling data, conducted during this research, strongly support the argument that the felsite hosted gold mineralization at Blue Rock, is neither unique nor accidental. It is just but, a simple product of the conjunction of favourable geological factors, no different to those that birthed typical GGB orogenic gold mineralization hosted within sheared sulphidic BIFs and quartz vein reefs. They all share the same geodynamic setting, fertility, preservation and regional architectural factors reminiscent of accretionary orogenic settings, albeit with differences in local architecture, variably controlled by geochemical and rheological properties of the different local host rocks. At deposit scale, the felsites occur as small dykes and sills emplaced along pre-existing structural zones of weakness. Gold mineralization is structurally controlled and associated mostly with brittle-ductile shears. During deformation, rheological contrast played a significant role in the selective failure of the more competent felsite rocks, resulting in the creation of permeability channels that allowed fluid migration. The more brittle and competent felsites acted as rigid bodies, that localised strain along their contacts with the surrounding less competent ductile mafic schists which acted as a relatively less permeable fluid cap rock. The irregular felsite contact zones with surrounding mafic schist caused a significant variation in the orientation of local principal maximum stress relative to the internally imposed regional stress, causing anomalously low minimum stress zones at deposit scale. Gold deposition occurred within low minimum stress structural traps dominated by sheared felsite contacts and their fractured interiors as well as triple junctions formed by complex structural geometries created by multiple felsite intrusions. The felsite hosted gold at Blue Rock can therefore be recognized as an orogenic gold mineral system archetype, for which an occurrence model is proposed. Understanding this type of mineralization is key for developing a robust exploration strategy - one that could be applied in a predictive capacity in exploration, to locate new economic gold deposits especially within well-endowed mature orogenic terrains, where exploration risk could be minimized by leveraging on new forward-thinking initiatives like Artificial Intelligence (AI) to re-analyze data from previous mining and exploration, allowing for a faster route to a return on investment. In a world of diminishing natural resources, the potential for previously ignored gold mineralization like the one at Blue Rock, becomes very significant. The prophetic words of Foster (1984), writing in Gold ‘82, therefore remain true and relevant to our time, that; “…. the way ahead for successful gold exploration is to search for new deposits not commonly recognized – in auriferous muds, disseminations in carbonate rocks, porphyries, and in felsic intrusive and extrusive volcanics…”. , Thesis (MSc) -- Faculty of Science, Geology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Mavuwa, Tavashavira
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464944 , vital:76559
- Description: The Blue Rock gold deposit was re-discovered by African Consolidated Resources (ACR) in 2007, over a defunct historical gold mine at Blue Rock, during a regional geochemical soil sampling program, within the Gadzema Greenstone Belt (GGB), in Central Zimbabwe. Most significant orogenic gold deposits within this belt occur as BIF- and quartz vein hosted orebodies. But unlike them, gold mineralization at Blue Rock is associated with felsite and quartz porphyry rocks. The GGB is a northern extension of the Midlands Greenstone Belt (MGB), where the common occurrence of mineralized felsites, in close association with major gold reefs within numerous gold mines is well documented. But no significant effort was directed towards their understanding or exploration in the past. They were never considered viable exploration targets for significant economic gold deposits, until recently. More attention was instead focused on high-grade BIF and quartz vein hosted gold, that dominate most orebodies exploited by numerous mines within the belt. At Blue Rock, ACR defined a significant JORC compliant felsite-hosted gold resource of close to a million ounces, which represents a brand new attractive open-pit mining opportunity. But the successful exploration for such type of mineralization, whose footprint is so different from the common ones previously mined within the GGB, no doubt, calls for a good understanding of this type of mineralization. Which makes felsite-hosted gold mineralization a prime candidate for research, based on a deposit whose discovery and development, I was fortunate to be part of during the past few years. In this contribution, the genesis, localization and economic significance of felsite-hosted gold mineralization is investigated, using the gold deposit at Blue Rock as a case study. The deposit could be understood best through the Mineral Systems Approach, used in this study to interrogate alternative ideas about its genesis using published information and deposit-scale exploratory data. Results from the synthesis of published information on the evolution of Archaean Greenstone Belts and genesis of their host orogenic gold deposits, are consistent with models that view orogenic terrains as having formed through horizontal accretion in modern-day like subduction-accretion systems, at continental margins, where orogenic gold deposition occurred via processes that could be explained quite simply, through a universal orogenic gold mineral systems model. According to this model, orogenic gold deposits are believed to have formed from near neutral fluids containing dissolved gold, generated directly from the devolatilization of a subducted oceanic slab together with its overlying gold-bearing sulphide-rich sedimentary package, or indirectly through fluid released from a mantle lithosphere that was originally metasomatized and fertilized during an earlier subduction event. The fluid migrated up-dip from the mantle to crustal levels, through advection or seismic pumping along lithosphere- to crustal-scale fault zones, to form orogenic gold deposits within lower order structures. If these models are all accurate, then the GGB formed through subduction-related east-directed horizontal accretion at the continental margins of the Sebakwe Proto-Craton (SPC), and the genesis of felsite-hosted gold mineralization at Blue Rock could be explained eloquently through a universal orogenic gold model, in which mantle derived auriferous fluids were localised within lower order structures associated with felsites during the late stages of terrain accretion. Evidence from surface mapping and 3D modelling of exploratory drilling data, conducted during this research, strongly support the argument that the felsite hosted gold mineralization at Blue Rock, is neither unique nor accidental. It is just but, a simple product of the conjunction of favourable geological factors, no different to those that birthed typical GGB orogenic gold mineralization hosted within sheared sulphidic BIFs and quartz vein reefs. They all share the same geodynamic setting, fertility, preservation and regional architectural factors reminiscent of accretionary orogenic settings, albeit with differences in local architecture, variably controlled by geochemical and rheological properties of the different local host rocks. At deposit scale, the felsites occur as small dykes and sills emplaced along pre-existing structural zones of weakness. Gold mineralization is structurally controlled and associated mostly with brittle-ductile shears. During deformation, rheological contrast played a significant role in the selective failure of the more competent felsite rocks, resulting in the creation of permeability channels that allowed fluid migration. The more brittle and competent felsites acted as rigid bodies, that localised strain along their contacts with the surrounding less competent ductile mafic schists which acted as a relatively less permeable fluid cap rock. The irregular felsite contact zones with surrounding mafic schist caused a significant variation in the orientation of local principal maximum stress relative to the internally imposed regional stress, causing anomalously low minimum stress zones at deposit scale. Gold deposition occurred within low minimum stress structural traps dominated by sheared felsite contacts and their fractured interiors as well as triple junctions formed by complex structural geometries created by multiple felsite intrusions. The felsite hosted gold at Blue Rock can therefore be recognized as an orogenic gold mineral system archetype, for which an occurrence model is proposed. Understanding this type of mineralization is key for developing a robust exploration strategy - one that could be applied in a predictive capacity in exploration, to locate new economic gold deposits especially within well-endowed mature orogenic terrains, where exploration risk could be minimized by leveraging on new forward-thinking initiatives like Artificial Intelligence (AI) to re-analyze data from previous mining and exploration, allowing for a faster route to a return on investment. In a world of diminishing natural resources, the potential for previously ignored gold mineralization like the one at Blue Rock, becomes very significant. The prophetic words of Foster (1984), writing in Gold ‘82, therefore remain true and relevant to our time, that; “…. the way ahead for successful gold exploration is to search for new deposits not commonly recognized – in auriferous muds, disseminations in carbonate rocks, porphyries, and in felsic intrusive and extrusive volcanics…”. , Thesis (MSc) -- Faculty of Science, Geology, 2024
- Full Text:
- Date Issued: 2024-10-11
HI analysis of resolved galaxies in the MeerKAT Absorption Line Survey
- Authors: Maina, Eric Kamau
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466701 , vital:76771 , DOI https://doi.org/10.21504/10962/466701
- Description: This doctoral thesis examines two galaxy groups, Klemola 31 and UGC439, leveraging the observational capabilities of the MeerKAT Absorption Line Survey (MALS). The focus was on studying the interstellar medium, specifically the neutral hydrogen (H i) content, distribution, density, and dynamics, through high spatial resolution observations of these groups, and therefore offering insights into the complex processes affecting galaxy evolution in different environments. To make use of an additional tool, the absorption line characteristics of Hi in the two observed systems were analysed and compared with the kinematics and the morphology as induced by the observation of the Hi emission line in the same systems. For Klemola 31, this thesis identifies significant Hi deficiencies and interactions between member galaxies, with notable evidence of tidal interactions between Klemola 31 A and Klemola 31 B as well as ESO400-11 and LEDA2807038; and possible ram-pressure stripping in ESO400-13. The combined analysis of the Hi in emission and absorption indicates the presence of an extraplanar and potential intra-group medium in the group. The UGC439 group was observed in the commissioning phase of the MeerKAT array, revealing contrasting Hi distributions, with the central three galaxies indicating Hi excess while the peripheral galaxies indicating Hi deficiencies. There are two Hi clouds, one close to the central three galaxies and the other to the north. In this case, the observations are consistent with an Hi absorption system from within the disk of a galaxy. This thesis also highlights the necessity for further high spatial and spectral resolution observations to further reveal the intricacies of gas dynamics and its critical role in the life-cycle of galaxies. It serves as an outlook for further studies of the Hi environment of galaxies by combining absorption and emission line studies as first provided by MALS and ultimately by deep Hi surveys with the Square Kilometre Array. This thesis is organised into four chapters. The first chapter details a few concepts and background information about the physics of galaxy evolution. Chapter two talks about Klemola 31 galaxy group, where we start by describing our observation, data reduction and source finding. Thereafter, we explore the Hi morphology and kinematics of this group. In Chapter Three, we turn our attention to UGC439 galaxy group and organise it in a similar manner. A summary and comparison of the two groups is presented in Chapter 4. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Maina, Eric Kamau
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466701 , vital:76771 , DOI https://doi.org/10.21504/10962/466701
- Description: This doctoral thesis examines two galaxy groups, Klemola 31 and UGC439, leveraging the observational capabilities of the MeerKAT Absorption Line Survey (MALS). The focus was on studying the interstellar medium, specifically the neutral hydrogen (H i) content, distribution, density, and dynamics, through high spatial resolution observations of these groups, and therefore offering insights into the complex processes affecting galaxy evolution in different environments. To make use of an additional tool, the absorption line characteristics of Hi in the two observed systems were analysed and compared with the kinematics and the morphology as induced by the observation of the Hi emission line in the same systems. For Klemola 31, this thesis identifies significant Hi deficiencies and interactions between member galaxies, with notable evidence of tidal interactions between Klemola 31 A and Klemola 31 B as well as ESO400-11 and LEDA2807038; and possible ram-pressure stripping in ESO400-13. The combined analysis of the Hi in emission and absorption indicates the presence of an extraplanar and potential intra-group medium in the group. The UGC439 group was observed in the commissioning phase of the MeerKAT array, revealing contrasting Hi distributions, with the central three galaxies indicating Hi excess while the peripheral galaxies indicating Hi deficiencies. There are two Hi clouds, one close to the central three galaxies and the other to the north. In this case, the observations are consistent with an Hi absorption system from within the disk of a galaxy. This thesis also highlights the necessity for further high spatial and spectral resolution observations to further reveal the intricacies of gas dynamics and its critical role in the life-cycle of galaxies. It serves as an outlook for further studies of the Hi environment of galaxies by combining absorption and emission line studies as first provided by MALS and ultimately by deep Hi surveys with the Square Kilometre Array. This thesis is organised into four chapters. The first chapter details a few concepts and background information about the physics of galaxy evolution. Chapter two talks about Klemola 31 galaxy group, where we start by describing our observation, data reduction and source finding. Thereafter, we explore the Hi morphology and kinematics of this group. In Chapter Three, we turn our attention to UGC439 galaxy group and organise it in a similar manner. A summary and comparison of the two groups is presented in Chapter 4. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2024
- Full Text:
- Date Issued: 2024-10-11
Immobilisation of an Aspergillus niger derived endo-1,4-β-mannanase, Man26A, for the production of prebiotic mannooligosaccharides from soybean meal
- Authors: Anderson, Amy Sage
- Date: 2024-10-11
- Subjects: Aspergillus niger , Soybean meal , Mannosidases , Oligosaccharides , Immobilized microorganisms
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463897 , vital:76455
- Description: This study investigated the potential for antibiotic alternatives in the form of prebiotics produced from the enzymatic breakdown of soybean meal (SBM). This study first investigated the immobilisation of an endo-1,4-β-mannanase derived from Aspergillus niger on glutaraldehyde-activated chitosan nanoparticles (CTS) and glutaraldehyde-activated chitosan-coated magnetic Fe3O4 nanoparticles (MAGS-CTS) - which could be effectively used to hydrolyse the galactomannan contained in SBM in a recyclable manner. The mannooligosaccharides (MOS) produced from the enzymatic digestion of SBM were then analysed for their prebiotic and antimicrobial capabilities to determine whether the strategy employed was capable of promoting and inhibiting probiotic and pathogenic growth, respectively. An Aspergillus niger endo-1,4-β-mannanase, Man26A, was confirmed by FTIR (Fourier-transform infrared spectroscopy) and XRD (X-ray powder diffraction) to be immobilised onto CTS and MAGS-CTS by covalent bonding. The immobilisation (%) and activity yields (%) were 81.14% and 35.45%, and 55.75% and 21.17%, respectively. The biochemical properties (pH and temperature optima, and temperature stability) of both the free CTS and MAGS-CTS immobilised Man26A enzymes were evaluated, with the pH optima shifting to a lower pH range after immobilisation (pH 2.0 – 3.0 vs. 5.0), while the temperature optima and stabilities remaining unchanged (at 60°C). CTS and free enzymes exhibited identical thermal stabilities, maintaining 100% activity for the first 6 hours at 55°C, while MAGS-CTS showed an immediate drop in relative activity after the first 30 minutes of incubation. Recyclability analysis revealed that CTS could be effectively reused for six reaction cycles, while the MAGS-CTS immobilised enzyme could only be used once. Both enzymes could be efficiently stored at 4ºC, showing a relative residual activity of 73% after 120 hours of storage. Substrate kinetic analysis showed that the free enzyme had the highest catalytic capabilities in hydrolysing locust bean gum (LBG), with the CTS immobilised enzyme was the most efficient in hydrolysing SBM, the insoluble, complex substrate. Sugar residues produced from the hydrolysis of LBG illustrated the effective breakdown of galactomannan to mannobiose (M2), mannotriose (M3), mannotetrose (M4), and mannohexose (M6). SBM-produced sugars analysed via TLC and HPLC indicated that the MOS residues were most probably glucose, galactose, and galactomannans (GM2 and GM3). The SBM-produced sugars were then evaluated for their prebiotic effect, illustrating their successful utilisation as a carbon source by probiotic bacteria; Streptococcus thermophilus, Bacillus subtilis and Lactobacillus bulgaricus. Evaluation of the antimicrobial activities of the SBM-produced sugars digested by probiotics suggested that their metabolites had the potential to be used as an antibiotic alternative. This study therefore illustrated that an endo-1,4-β-mannanase derived from Aspergillus niger could be immobilised successfully, for use in a recyclable reaction to produce MOS products. This study also described the successful use of SBM-sugars as a prebiotic, indicating a successful alternative to antibiotic growth promoters (AGP) by illustrating their positive effect on inhibiting growth of pathogenic bacterial species. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Anderson, Amy Sage
- Date: 2024-10-11
- Subjects: Aspergillus niger , Soybean meal , Mannosidases , Oligosaccharides , Immobilized microorganisms
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463897 , vital:76455
- Description: This study investigated the potential for antibiotic alternatives in the form of prebiotics produced from the enzymatic breakdown of soybean meal (SBM). This study first investigated the immobilisation of an endo-1,4-β-mannanase derived from Aspergillus niger on glutaraldehyde-activated chitosan nanoparticles (CTS) and glutaraldehyde-activated chitosan-coated magnetic Fe3O4 nanoparticles (MAGS-CTS) - which could be effectively used to hydrolyse the galactomannan contained in SBM in a recyclable manner. The mannooligosaccharides (MOS) produced from the enzymatic digestion of SBM were then analysed for their prebiotic and antimicrobial capabilities to determine whether the strategy employed was capable of promoting and inhibiting probiotic and pathogenic growth, respectively. An Aspergillus niger endo-1,4-β-mannanase, Man26A, was confirmed by FTIR (Fourier-transform infrared spectroscopy) and XRD (X-ray powder diffraction) to be immobilised onto CTS and MAGS-CTS by covalent bonding. The immobilisation (%) and activity yields (%) were 81.14% and 35.45%, and 55.75% and 21.17%, respectively. The biochemical properties (pH and temperature optima, and temperature stability) of both the free CTS and MAGS-CTS immobilised Man26A enzymes were evaluated, with the pH optima shifting to a lower pH range after immobilisation (pH 2.0 – 3.0 vs. 5.0), while the temperature optima and stabilities remaining unchanged (at 60°C). CTS and free enzymes exhibited identical thermal stabilities, maintaining 100% activity for the first 6 hours at 55°C, while MAGS-CTS showed an immediate drop in relative activity after the first 30 minutes of incubation. Recyclability analysis revealed that CTS could be effectively reused for six reaction cycles, while the MAGS-CTS immobilised enzyme could only be used once. Both enzymes could be efficiently stored at 4ºC, showing a relative residual activity of 73% after 120 hours of storage. Substrate kinetic analysis showed that the free enzyme had the highest catalytic capabilities in hydrolysing locust bean gum (LBG), with the CTS immobilised enzyme was the most efficient in hydrolysing SBM, the insoluble, complex substrate. Sugar residues produced from the hydrolysis of LBG illustrated the effective breakdown of galactomannan to mannobiose (M2), mannotriose (M3), mannotetrose (M4), and mannohexose (M6). SBM-produced sugars analysed via TLC and HPLC indicated that the MOS residues were most probably glucose, galactose, and galactomannans (GM2 and GM3). The SBM-produced sugars were then evaluated for their prebiotic effect, illustrating their successful utilisation as a carbon source by probiotic bacteria; Streptococcus thermophilus, Bacillus subtilis and Lactobacillus bulgaricus. Evaluation of the antimicrobial activities of the SBM-produced sugars digested by probiotics suggested that their metabolites had the potential to be used as an antibiotic alternative. This study therefore illustrated that an endo-1,4-β-mannanase derived from Aspergillus niger could be immobilised successfully, for use in a recyclable reaction to produce MOS products. This study also described the successful use of SBM-sugars as a prebiotic, indicating a successful alternative to antibiotic growth promoters (AGP) by illustrating their positive effect on inhibiting growth of pathogenic bacterial species. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
Integrating sustainability into strategic decision making in the South African automotive sector
- Authors: Makaudi, Tuelo Ivan
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/461874 , vital:76247
- Description: Sustainability has become a major topic for businesses, policy makers, government, and researchers. With the growing awareness of climate change, environmental and social problems, attention has turned to how businesses impact the environment, society, and economy. Sustainability, therefore, requires the integration of environmental and social issues into strategic decision making. Many organizations consider sustainability as an important issue for the business. However, some companies are struggling to combine business success and the success of other stakeholders, particularly those representing the interests of the environment and society. The purpose of this case study is to explore how sustainability is integrated into strategic decision making within some companies in the South African automotive industry. This study followed a qualitative approach, and semi-structured interviews were conducted with ten senior managers in the automotive sector in South Africa. The study used an inductive thematic analysis approach to analyse the data, and five main themes were generated: (1) Business profitability, (2) Organization culture, (3) Rationality, (4) Compliance, and (5) Corporate social responsibility (CSR). The findings of the study indicated that strategic decisions made considered business profitability first and foremost above environment and society. There is evidence that businesses engage in some sustainability activities, but this was related to the business objective to be profitable and to meet compliance requirements. The findings of the study also indicated that a rational decision-making approach was used predominantly, compared to intuitive and political approaches. This was due to the cautious approach of maintaining profit-making as a primary business objective. In terms of recommendations, this study recommends that automotive companies in South Africa integrate sustainability considerations into organizational/or business strategy to enable the industry to create shared value for the environment, society and economy. Integrating sustainability into business strategy will align business practices with sustainability goals and therefore allowing the automotive industry to have a positive impact in the society and environment which in turn will lead to improved financial performance. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Makaudi, Tuelo Ivan
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/461874 , vital:76247
- Description: Sustainability has become a major topic for businesses, policy makers, government, and researchers. With the growing awareness of climate change, environmental and social problems, attention has turned to how businesses impact the environment, society, and economy. Sustainability, therefore, requires the integration of environmental and social issues into strategic decision making. Many organizations consider sustainability as an important issue for the business. However, some companies are struggling to combine business success and the success of other stakeholders, particularly those representing the interests of the environment and society. The purpose of this case study is to explore how sustainability is integrated into strategic decision making within some companies in the South African automotive industry. This study followed a qualitative approach, and semi-structured interviews were conducted with ten senior managers in the automotive sector in South Africa. The study used an inductive thematic analysis approach to analyse the data, and five main themes were generated: (1) Business profitability, (2) Organization culture, (3) Rationality, (4) Compliance, and (5) Corporate social responsibility (CSR). The findings of the study indicated that strategic decisions made considered business profitability first and foremost above environment and society. There is evidence that businesses engage in some sustainability activities, but this was related to the business objective to be profitable and to meet compliance requirements. The findings of the study also indicated that a rational decision-making approach was used predominantly, compared to intuitive and political approaches. This was due to the cautious approach of maintaining profit-making as a primary business objective. In terms of recommendations, this study recommends that automotive companies in South Africa integrate sustainability considerations into organizational/or business strategy to enable the industry to create shared value for the environment, society and economy. Integrating sustainability into business strategy will align business practices with sustainability goals and therefore allowing the automotive industry to have a positive impact in the society and environment which in turn will lead to improved financial performance. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2024
- Full Text:
- Date Issued: 2024-10-11
Investigating the relationship between Adverse Childhood Experiences (ACE) and attention skills in children living with HIV
- Authors: Ngomane, Sibongile
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465821 , vital:76656
- Description: Background: While persons living with HIV (PWH) have benefited from significant advances in antiretroviral (ARV) treatment, neurocognitive deficits sequent HIV, remain elevated in this population. Notwithstanding HIV, adverse childhood experiences (ACEs) have been implicated in compromised neurocognitive outcomes in children living with HIV. There however, continues to be a dearth of research, investigating the intertwined nature of HIV, ACEs, and neurocognition in pediatric and adolescent HIV. Objectives: This study investigated the relationship between ACEs (High vs Low) and attention outcomes, in children and adolescents, living with HIV, a residing at HIV care shelters in South Africa. Methods: A non-experimental quantitative research design, inclusive of 42 participants (n = 22 males; n = 20 females), was employed to answer the research questions pertinent to the study. Measures of neurocognition were assessed using the NEPSY-II. Adverse childhood experiences were assessed using the ACE CYW-Qs. Independent Sample t-test and Hierarchical regression analysis were conducted to answer research goals, using jamovi 2.3.21 statistical software. Results: The study found that participants who reported a high number of ACEs also performed poorly on attention measures. There were inconclusive findings on the effect of biological sex and age, on attention outcomes. Conclusion: Higher levels of childhood adversities are associated with poorer outcomes in attention scores among children living with HIV. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Ngomane, Sibongile
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465821 , vital:76656
- Description: Background: While persons living with HIV (PWH) have benefited from significant advances in antiretroviral (ARV) treatment, neurocognitive deficits sequent HIV, remain elevated in this population. Notwithstanding HIV, adverse childhood experiences (ACEs) have been implicated in compromised neurocognitive outcomes in children living with HIV. There however, continues to be a dearth of research, investigating the intertwined nature of HIV, ACEs, and neurocognition in pediatric and adolescent HIV. Objectives: This study investigated the relationship between ACEs (High vs Low) and attention outcomes, in children and adolescents, living with HIV, a residing at HIV care shelters in South Africa. Methods: A non-experimental quantitative research design, inclusive of 42 participants (n = 22 males; n = 20 females), was employed to answer the research questions pertinent to the study. Measures of neurocognition were assessed using the NEPSY-II. Adverse childhood experiences were assessed using the ACE CYW-Qs. Independent Sample t-test and Hierarchical regression analysis were conducted to answer research goals, using jamovi 2.3.21 statistical software. Results: The study found that participants who reported a high number of ACEs also performed poorly on attention measures. There were inconclusive findings on the effect of biological sex and age, on attention outcomes. Conclusion: Higher levels of childhood adversities are associated with poorer outcomes in attention scores among children living with HIV. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
- Full Text:
- Date Issued: 2024-10-11
IT business consulting competencies to address business intelligence and analytics challenges in South African organisations
- Authors: Chatapura, Ruvimbo Faith
- Date: 2024-10-11
- Subjects: Business enterprises Information technology South Africa , Business intelligence , Business analytics , Business consultants , Dynamic capabilities , Knowledge management
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/462680 , vital:76325
- Description: Background: In today's dynamic environment, the importance and popularity of business intelligence and analytics (BI&A) has increased due to the rise in big data being generated across the globe. BI&A is an essential emerging business competency area and dynamic capability that serves as an enabler for organisations to harvest value from their big data. When implemented correctly, BI&A is a powerful tool that leads to increased competitive advantage. However, organisations in South Africa are facing major challenges when it comes to adopting and harnessing it. As such, it is IT business consultants that South African organisations turn to for acquiring BI&A expertise. Objective: Using the Theory of Dynamic Capabilities as an underpinning lens, the purpose of this study is to investigate the relevant competencies IT business consultants need to address BI&A challenges in South African organisations. This study focuses on developing a BI&A competency framework based on these competencies that IT business consultants can consider when addressing the BI&A challenges in South African organisations. Methods: A qualitative research approach was utilised in this study by making use of an interpretive paradigm, abductive reasoning, qualitative description research strategy, as well as semi-structured interviews and questionnaires as data collection methods to elicit feedback on this study’s BI&A competency framework. Content analysis was conducted to categorise and code the interview data, and descriptive analysis was conducted to rank the competencies in order of relevance. Findings: It was found that the relevant business competencies to consider are business acumen, industry knowledge and strategic conceptual abilities. The relevant technical competencies are categorised into three categories: analytical skills (logical thinking, problem-solving, statistical analysis and what-if analysis), data engineering (data modelling skills, data warehousing, database management, data governance, data interpretation, data stewardship, data visualisation tools and data processing languages) and supplementary skills (project management, consulting skills and artificial intelligence). The relevant values and behavioural competencies to consider are integrity, communication, teamwork, resilience, commitment, creativity, emotional intelligence, humility, behavioural analysis, curiosity, leadership and social intelligence. , Thesis (MCom) -- Faculty of Commerce, Information Systems, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Chatapura, Ruvimbo Faith
- Date: 2024-10-11
- Subjects: Business enterprises Information technology South Africa , Business intelligence , Business analytics , Business consultants , Dynamic capabilities , Knowledge management
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/462680 , vital:76325
- Description: Background: In today's dynamic environment, the importance and popularity of business intelligence and analytics (BI&A) has increased due to the rise in big data being generated across the globe. BI&A is an essential emerging business competency area and dynamic capability that serves as an enabler for organisations to harvest value from their big data. When implemented correctly, BI&A is a powerful tool that leads to increased competitive advantage. However, organisations in South Africa are facing major challenges when it comes to adopting and harnessing it. As such, it is IT business consultants that South African organisations turn to for acquiring BI&A expertise. Objective: Using the Theory of Dynamic Capabilities as an underpinning lens, the purpose of this study is to investigate the relevant competencies IT business consultants need to address BI&A challenges in South African organisations. This study focuses on developing a BI&A competency framework based on these competencies that IT business consultants can consider when addressing the BI&A challenges in South African organisations. Methods: A qualitative research approach was utilised in this study by making use of an interpretive paradigm, abductive reasoning, qualitative description research strategy, as well as semi-structured interviews and questionnaires as data collection methods to elicit feedback on this study’s BI&A competency framework. Content analysis was conducted to categorise and code the interview data, and descriptive analysis was conducted to rank the competencies in order of relevance. Findings: It was found that the relevant business competencies to consider are business acumen, industry knowledge and strategic conceptual abilities. The relevant technical competencies are categorised into three categories: analytical skills (logical thinking, problem-solving, statistical analysis and what-if analysis), data engineering (data modelling skills, data warehousing, database management, data governance, data interpretation, data stewardship, data visualisation tools and data processing languages) and supplementary skills (project management, consulting skills and artificial intelligence). The relevant values and behavioural competencies to consider are integrity, communication, teamwork, resilience, commitment, creativity, emotional intelligence, humility, behavioural analysis, curiosity, leadership and social intelligence. , Thesis (MCom) -- Faculty of Commerce, Information Systems, 2024
- Full Text:
- Date Issued: 2024-10-11
Macroinvertebrate population dynamics, community composition and diversity patterns of two coastal lakes in northern KwaZulu-Natal, South Africa
- Authors: Campbell, Kaylee Maria
- Date: 2024-10-11
- Subjects: Indicators (Biology) , Lakes South Africa KwaZulu-Natal , Sibayi, Lake (South Africa) , Lake Mzingazi Dam , Biological monitoring South Africa KwaZulu-Natal , Biodiversity , Geospatial data South Africa KwaZulu-Natal , Land use Planning South Africa KwaZulu-Natal
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464406 , vital:76508
- Description: The 2018 South African National Biodiversity Assessment (NBA) identified eight freshwater lakes of national ecological importance and a lack of understanding of their biology. The assessment further called for baseline foundational data for their conservation. Aquatic invertebrates are considered to be reliable and sensitive biological indicators of environmental and water quality changes, and understanding aquatic invertebrate dynamics in these systems will provide a comprehensive understanding of how they can be better protected. The NBA also highlighted a gap in data associated with ecological response to landscape developments and climate change (mainly below average precipitation and increased temperatures) and how this contributes to aquatic resource conservation. This further complicates the modelling of important ecological thresholds and hampers the prediction of possible responses of these ecosystems to environmental changes. This gap informed the aims and rationale of this dissertation; to identify longer-term spatiotemporal trends in aquatic invertebrate communities in Lake Sibaya and Lake Mzingazi and to determine whether the surrounding land use changes could lead to long-term changes in aquatic invertebrate communities of both lakes by comparing recent survey data with historical datasets. In Chapter 2, this dissertation investigated the population dynamics of freshwater shrimp, Caridina africana in Lake Sibaya and Mzingazi and compared the data to that of 1975 study published by Hart (1981). This was done to assess any changes in the C. africana populations due to the considerable changes in land use and weather patterns that have occurred in the last 48 years in and around the systems. Results from Lake Sibaya and Lake Mzingazi were also compared to determine any differences in urban and agricultural stressors presented to C. africana populations. This chapter hypothesised that increases in anthropogenic pollution, invasive species and other habitat modifications at Lake Sibaya and Lake Mzingazi would lead to (1) reductions in shrimp densities and changes in population dynamics when comparing with the 1975 data from Hart (1981). Additionally, it was predicted that (2) Caridina africana abundances found at Lake Mzingazi would be lower than those found at Lake Sibaya (3) due to different water quality variables associated with land use. Results showed that C. africana population densities at Lake Sibaya and lake level recordings had experienced significant decreases since 1975 with densities being significantly lower in 2021. Additional differences seen in 2021 when compared to 1975 were that females were more abundant than males, individuals between the sizes of 3mm and 5mm were most abundant instead of those in the smallest size class (<0.83mm – 1.67mm) and females only dominated size classes above 4mm instead of all size classes above 2.5mm. Populations at Lake Sibaya were negatively correlated with nitrate concentrations in 2021 and populations at Lake Mzingazi were negatively correlated with temperature according to generalised linear models. These results emphasized the importance of pollution mitigation, sustainable water abstraction and the maintenance of natural water temperature ranges in the conservation of lentic C. africana populations. There was also no evidence that urbanisation and agriculture presented different threats to freshwater shrimp populations. In Chapter 3, this dissertation aimed to quantify the littoral aquatic invertebrate diversity and assemblage patterns from Lake Sibaya and Lake Mzingazi to provide comprehensive baseline datasets for these coastal systems. This chapter also aimed to investigate the impacts of landscape developments and habitat change on aquatic invertebrate communities by understanding significant water quality parameters as drivers of community variation. Predictions for Chapter 3 were that increases in agricultural and anthropogenic disturbance and habitat modification will lead to (1) aquatic invertebrate community composition at lakes Sibaya and Mzingazi being structured according to water quality variables that stem from surrounding land-use activities, leading to (2) differing community structures at each lake. Lastly, it was hypothesised that (3) the presence of the invasive snail Tarebia granifera would likely be affecting the aquatic invertebrate diversity and composition of both lakes. According to linear models, aquatic invertebrate abundance at Lake Sibaya was negatively affected by salinity, lake level and phosphate concentration, and positively associated with temperature. Taxa richness and Pielou’s evenness at the lake were negatively associated with conductivity and nitrate concentrations respectively. The aquatic invertebrate community at Lake Sibaya also followed typical seasonal patterns. At Lake Mzingazi, Pielou’s evenness was negatively associated with nitrate and ammonium concentrations and no typical seasonal patterns were evident in the community composition. Communities at Lake Mzingazi also exhibited resilience despite changes in physicochemical parameters, emphasising the difficulty in predicting aquatic community response to habitat modification due to lake-specific community resilience. Tarebia granifera populations at Lake Sibaya were found to negatively affect invertebrate diversity scores according to generalised linear models. Additionally, no individuals of Melanoides tuberculata were found in either system indicating the possibility that these native snails may have been outcompeted by their invasive counterpart. The prevalence of significant stressors associated with habitat disturbance and the unexpected results seen at Lake Mzingazi emphasized the importance of monitoring aquatic invertebrate communities in response to climate change and associated land use developments to adequately understand the long-term threats these changes pose to freshwater ecosystems and biodiversity conservation. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Campbell, Kaylee Maria
- Date: 2024-10-11
- Subjects: Indicators (Biology) , Lakes South Africa KwaZulu-Natal , Sibayi, Lake (South Africa) , Lake Mzingazi Dam , Biological monitoring South Africa KwaZulu-Natal , Biodiversity , Geospatial data South Africa KwaZulu-Natal , Land use Planning South Africa KwaZulu-Natal
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464406 , vital:76508
- Description: The 2018 South African National Biodiversity Assessment (NBA) identified eight freshwater lakes of national ecological importance and a lack of understanding of their biology. The assessment further called for baseline foundational data for their conservation. Aquatic invertebrates are considered to be reliable and sensitive biological indicators of environmental and water quality changes, and understanding aquatic invertebrate dynamics in these systems will provide a comprehensive understanding of how they can be better protected. The NBA also highlighted a gap in data associated with ecological response to landscape developments and climate change (mainly below average precipitation and increased temperatures) and how this contributes to aquatic resource conservation. This further complicates the modelling of important ecological thresholds and hampers the prediction of possible responses of these ecosystems to environmental changes. This gap informed the aims and rationale of this dissertation; to identify longer-term spatiotemporal trends in aquatic invertebrate communities in Lake Sibaya and Lake Mzingazi and to determine whether the surrounding land use changes could lead to long-term changes in aquatic invertebrate communities of both lakes by comparing recent survey data with historical datasets. In Chapter 2, this dissertation investigated the population dynamics of freshwater shrimp, Caridina africana in Lake Sibaya and Mzingazi and compared the data to that of 1975 study published by Hart (1981). This was done to assess any changes in the C. africana populations due to the considerable changes in land use and weather patterns that have occurred in the last 48 years in and around the systems. Results from Lake Sibaya and Lake Mzingazi were also compared to determine any differences in urban and agricultural stressors presented to C. africana populations. This chapter hypothesised that increases in anthropogenic pollution, invasive species and other habitat modifications at Lake Sibaya and Lake Mzingazi would lead to (1) reductions in shrimp densities and changes in population dynamics when comparing with the 1975 data from Hart (1981). Additionally, it was predicted that (2) Caridina africana abundances found at Lake Mzingazi would be lower than those found at Lake Sibaya (3) due to different water quality variables associated with land use. Results showed that C. africana population densities at Lake Sibaya and lake level recordings had experienced significant decreases since 1975 with densities being significantly lower in 2021. Additional differences seen in 2021 when compared to 1975 were that females were more abundant than males, individuals between the sizes of 3mm and 5mm were most abundant instead of those in the smallest size class (<0.83mm – 1.67mm) and females only dominated size classes above 4mm instead of all size classes above 2.5mm. Populations at Lake Sibaya were negatively correlated with nitrate concentrations in 2021 and populations at Lake Mzingazi were negatively correlated with temperature according to generalised linear models. These results emphasized the importance of pollution mitigation, sustainable water abstraction and the maintenance of natural water temperature ranges in the conservation of lentic C. africana populations. There was also no evidence that urbanisation and agriculture presented different threats to freshwater shrimp populations. In Chapter 3, this dissertation aimed to quantify the littoral aquatic invertebrate diversity and assemblage patterns from Lake Sibaya and Lake Mzingazi to provide comprehensive baseline datasets for these coastal systems. This chapter also aimed to investigate the impacts of landscape developments and habitat change on aquatic invertebrate communities by understanding significant water quality parameters as drivers of community variation. Predictions for Chapter 3 were that increases in agricultural and anthropogenic disturbance and habitat modification will lead to (1) aquatic invertebrate community composition at lakes Sibaya and Mzingazi being structured according to water quality variables that stem from surrounding land-use activities, leading to (2) differing community structures at each lake. Lastly, it was hypothesised that (3) the presence of the invasive snail Tarebia granifera would likely be affecting the aquatic invertebrate diversity and composition of both lakes. According to linear models, aquatic invertebrate abundance at Lake Sibaya was negatively affected by salinity, lake level and phosphate concentration, and positively associated with temperature. Taxa richness and Pielou’s evenness at the lake were negatively associated with conductivity and nitrate concentrations respectively. The aquatic invertebrate community at Lake Sibaya also followed typical seasonal patterns. At Lake Mzingazi, Pielou’s evenness was negatively associated with nitrate and ammonium concentrations and no typical seasonal patterns were evident in the community composition. Communities at Lake Mzingazi also exhibited resilience despite changes in physicochemical parameters, emphasising the difficulty in predicting aquatic community response to habitat modification due to lake-specific community resilience. Tarebia granifera populations at Lake Sibaya were found to negatively affect invertebrate diversity scores according to generalised linear models. Additionally, no individuals of Melanoides tuberculata were found in either system indicating the possibility that these native snails may have been outcompeted by their invasive counterpart. The prevalence of significant stressors associated with habitat disturbance and the unexpected results seen at Lake Mzingazi emphasized the importance of monitoring aquatic invertebrate communities in response to climate change and associated land use developments to adequately understand the long-term threats these changes pose to freshwater ecosystems and biodiversity conservation. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2024
- Full Text:
- Date Issued: 2024-10-11
Mediating learning of sound through cultural music and dance stories to Grade 4 farm school learners
- Authors: Tshitshi, Hlengiwe
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463647 , vital:76428
- Description: The current South African Natural Science and Technology (NS-Tech) curriculum for grades 4–9 encourages teachers to integrate Indigenous Knowledge (IK) into their teaching. By doing so, it is hoped that this would contextualise and make science relevant to learners. However, the contradiction is that IK is hardly discussed in the curriculum and there are no clear guidelines on how to integrate it. It is against this background that in this study I used stories about cultural beliefs and practices on traditional music and dance to support Grade 4 NS-Tech from a farm school talking about and making sense of the topic of sound. This study is underpinned by the interpretivist and Indigenous research paradigms. Within the Indigenous research paradigm, I focused on the Ubuntu perspective. A qualitative case study research design was employed, and the study was conducted in the Sarah Baartman District of the Eastern Cape. Four Grade 4 learners and four Indigenous Knowledge Custodians who were all family members were participants in this study. In addition, I invited an NS-Tech teacher to be my critical friend in this study. A focus group interview (sharing circle), participatory and lesson observations and learners’ journal reflections were employed to gather data. Vygotsky’s sociocultural theory together with Ogunniyi’s contiguity argumentative theory were used as lenses to analyse data. A thematic approach to data analysis was employed to come up with sub-themes. Thereafter, common sub-themes were subsequently combined to form themes. The findings of this study revealed that the following factors can significantly enable/constrain the ability of Grade 4 Natural Sciences and Technology learners from a farm school to comprehend and engage with the topic of sound: (1) integration of IK into science lessons, (2) Experiential learning through hands-on activities, (3) Community involvement in knowledge acquisition, and (4) Emotional effect of loud sounds. In addition, the contribution of Indigenous Knowledge Custodians facilitated a notable enhancement in learners’ dialogue and understanding of sound. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
Mediating learning of sound through cultural music and dance stories to Grade 4 farm school learners
- Authors: Tshitshi, Hlengiwe
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463647 , vital:76428
- Description: The current South African Natural Science and Technology (NS-Tech) curriculum for grades 4–9 encourages teachers to integrate Indigenous Knowledge (IK) into their teaching. By doing so, it is hoped that this would contextualise and make science relevant to learners. However, the contradiction is that IK is hardly discussed in the curriculum and there are no clear guidelines on how to integrate it. It is against this background that in this study I used stories about cultural beliefs and practices on traditional music and dance to support Grade 4 NS-Tech from a farm school talking about and making sense of the topic of sound. This study is underpinned by the interpretivist and Indigenous research paradigms. Within the Indigenous research paradigm, I focused on the Ubuntu perspective. A qualitative case study research design was employed, and the study was conducted in the Sarah Baartman District of the Eastern Cape. Four Grade 4 learners and four Indigenous Knowledge Custodians who were all family members were participants in this study. In addition, I invited an NS-Tech teacher to be my critical friend in this study. A focus group interview (sharing circle), participatory and lesson observations and learners’ journal reflections were employed to gather data. Vygotsky’s sociocultural theory together with Ogunniyi’s contiguity argumentative theory were used as lenses to analyse data. A thematic approach to data analysis was employed to come up with sub-themes. Thereafter, common sub-themes were subsequently combined to form themes. The findings of this study revealed that the following factors can significantly enable/constrain the ability of Grade 4 Natural Sciences and Technology learners from a farm school to comprehend and engage with the topic of sound: (1) integration of IK into science lessons, (2) Experiential learning through hands-on activities, (3) Community involvement in knowledge acquisition, and (4) Emotional effect of loud sounds. In addition, the contribution of Indigenous Knowledge Custodians facilitated a notable enhancement in learners’ dialogue and understanding of sound. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
Medical pluralism amongst Makhanda traditional health practitioners: Exploring dispositions to COVID-19 vaccinations
- Authors: Mothapo, Lebogang
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466284 , vital:76714
- Description: ‘Healers and healing’, ‘wellbeing and prevalence’, ‘medical systems and progression’. Every healing concept is tied to people’s perspectives, thoughts, beliefs, and backgrounds. Worldviews and world perspectives influence these throughout time and space. The progressive postulation between medical systems and the comprehensive relations between them is a narrative worth exploring through the distinct perspectives of Traditional Health Practitioners in Makhanda. This qualitative study sought to explore the dispositions of Traditional Health Practitioners (THPs) towards COVID-19 vaccinations to understand the practice and acceptance of medical pluralism through a traditional lens. Through purposive and snowball sampling, 10 participants were recruited and semi-structured in-depth interviews were conducted as a tool for data collection. Thematic data analysis was conducted to analyse the data, and multiple codes that led to themes emerged. THPs exhibit multiple concepts tied to COVID-19 vaccination, representing the dynamic understanding of participating in biomedical approaches. THPs, in their decision to uptake the COVID-19 vaccination, are motivated by the severity of the disease and other compelling reasons, such as the obligations and regulations put in place to encourage vaccination uptake in achieving mass/herd immunity. THPs who, in their decision of not uptaking the COVID-19 vaccination, display mistrust, disregard for the COVID-19 vaccination in particular and the entrusted commitment to traditional medicine. In all the expressed dispositions, reliance on the understanding of COVID-19 and the dependence on lived experiences played an integral role in how THPs responded to COVID-19 vaccinations. Due to this understanding, the practice of medical pluralism amongst Makhanda THPs is understood through context-based concepts to explore the in-depth multifaceted positioning of medical pluralism. , Thesis (MSocSci) -- Faculty of Humanities, Anthropology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Mothapo, Lebogang
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466284 , vital:76714
- Description: ‘Healers and healing’, ‘wellbeing and prevalence’, ‘medical systems and progression’. Every healing concept is tied to people’s perspectives, thoughts, beliefs, and backgrounds. Worldviews and world perspectives influence these throughout time and space. The progressive postulation between medical systems and the comprehensive relations between them is a narrative worth exploring through the distinct perspectives of Traditional Health Practitioners in Makhanda. This qualitative study sought to explore the dispositions of Traditional Health Practitioners (THPs) towards COVID-19 vaccinations to understand the practice and acceptance of medical pluralism through a traditional lens. Through purposive and snowball sampling, 10 participants were recruited and semi-structured in-depth interviews were conducted as a tool for data collection. Thematic data analysis was conducted to analyse the data, and multiple codes that led to themes emerged. THPs exhibit multiple concepts tied to COVID-19 vaccination, representing the dynamic understanding of participating in biomedical approaches. THPs, in their decision to uptake the COVID-19 vaccination, are motivated by the severity of the disease and other compelling reasons, such as the obligations and regulations put in place to encourage vaccination uptake in achieving mass/herd immunity. THPs who, in their decision of not uptaking the COVID-19 vaccination, display mistrust, disregard for the COVID-19 vaccination in particular and the entrusted commitment to traditional medicine. In all the expressed dispositions, reliance on the understanding of COVID-19 and the dependence on lived experiences played an integral role in how THPs responded to COVID-19 vaccinations. Due to this understanding, the practice of medical pluralism amongst Makhanda THPs is understood through context-based concepts to explore the in-depth multifaceted positioning of medical pluralism. , Thesis (MSocSci) -- Faculty of Humanities, Anthropology, 2024
- Full Text:
- Date Issued: 2024-10-11
MeerKAT: a journey from commissioning to science
- Authors: Hugo, Benjamin Vorster
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466871 , vital:76794 , DOI https://doi.org/10.21504/10962/466871
- Description: This dissertation presents a collection of work completed for the South African Radio Astronomy Observatory in characterizing calibrator fields PKS B1934-638, PKS B0407-65 and 3C286, the development of a facet-based multi-direction peeling scheme for the CUBICAL calibration framework and incorporation into an end-to-end containerized data reduction framework, a study of a transitional millisecond pulsar candidate, and characterization of baseline dependent archiving tooling for MeerKAT. Our long term studies of PKS B1934-638, PKS B0407-65 indicate that these bandpass and flux calibrators are stable over multiple years. We also find that, especially at low frequencies in the UHF band, the population of sources surrounding these stellar Gigahertz Peaked Sources (GPS) can contribute to errors two to three orders of magnitude above desired bandpass calibration solution stability, if left unmodeled. We derive new new full sky models of these fields, currently in use by the MeerKAT Science Data Processor. We characterize the MeerKAT feed alignment using the refraction-driven linearly polarized thermal light from the Moon in order to derive a new model for the linear polarization of the stable quasar 3C286 down to 544 MHz. Part of this work includes characterization of ionospheric corrections using the International Global Navigation Satelite System Service and direct measurement of total electron content above the MeerKAT site using interchange data from the South African TrigNET service. We find that current commonly-employed techniques achieve corrections to ionospheric Faraday rotation no better than 1 rad m2. This is the main limitation on the accuracy of polarimetric observation using the MeerKAT array. We find that 3C286 intrinsically depolarizes at frequencies below 1 GHz, with an associated non-linear increase in the intrinsic source rotation measure. We present an improvement to workflows using the CUBICAL calibration framework, developed at Rhodes University. Modern radio interferometers presents a significant challenge to calibrate, often necessitating memory and computeintensive direction-dependent calibration towards many directions in order to improve the fidelity of radio images in order to meet scientific goals. We developed a framework to simplify the model prediction aspect of these direction-dependent calibration workflows using targeted faceting. Using our scheme users use models derived from the DDFACET imaging package and only need to provide lattices to mark regions of sky to which direction-dependent calibration solutions need to be solved for. This simplifies a laborious multi-step process in traditional calibration packages that need to be executed per direction. The approach is compared to an image-space corrective regime and incorporated into the VERMEERKAT end-to-end calibration framework for MeerKAT data. The improved direction-dependent calibration techniques were then applied in an analysis of the transitional millisecond pulsar candidate CXOU J110926.4-650224. The link between accreting binary systems (where emission is dominated by the synchrotron emission of relativistic jets from thermo-nuclear reaction onto the Neutron Star surface by the infalling matter) and binary radio pulsars is currently elusive. This is due to the lack of a large population of such transitional systems — only three confirmed transitional systems are known at the time of writing. It is thought that infalling matter effectively quenches the radio pulsar mechanism. Our candidate was found to be variable in the optical and the X-ray, with transitions between low, high and flaring states lasting anywhere from a tens of seconds to tens of minutes, seen in archival observations spanning nearly three decades. For the first time we detect low level synchrotron emission (_ 50 mJy beam1) coincident with this system using MeerKAT, including a flare within minutes of a flare detected in X-ray using the XMM-Newton observatory. Our analysis indicate that there is no clear anti-correlated behaviour between radio and X-ray state transitions in this system, unlike other candidate systems—indicating that such transitional systems may not exhibit homogenous behaviour. This suggests that the processes driving the X-ray mode-switching in this system are not directly linked to the processes responsible for emitting radio synchrotron radiation. Finally, we consider the problem of MeerKAT data archiving. We present a qualification analysis, using MeerKAT data, of the Rhodes University baseline-dependent archiving package XOVA, which can be used to compress and archive MeerKAT data in interchange standard-compliant format. The data rates from interferometric array radio telescopes, such as MeerKAT, grow as the square of the number of antennas in such an array. For the sake of reproducibility and future reanalysis it is important to archive calibrated visibility products. The degree to which calibrated visibility products can be compressed, by averaging, depends on the amount of smearing that can be tolerated at a fixed distance from the center of the images synthesized from these visibility products. This is, traditionally, set by the longest spacing in the interferometric array, with all other spacings averaged to the same integration and channelization as the longest spacing. We find that, using baseline-dependent averaging techniques – where averaging intervals are set per interferometric spacing – we can achieve space savings an order of magnitude better than traditional averaging approaches, with no appreciable loss of image fidelity when compared to traditional averaging approaches. , Thesis (PhD) -- Faculty of Science, Faculty of Science, Physics and Electronics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Hugo, Benjamin Vorster
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466871 , vital:76794 , DOI https://doi.org/10.21504/10962/466871
- Description: This dissertation presents a collection of work completed for the South African Radio Astronomy Observatory in characterizing calibrator fields PKS B1934-638, PKS B0407-65 and 3C286, the development of a facet-based multi-direction peeling scheme for the CUBICAL calibration framework and incorporation into an end-to-end containerized data reduction framework, a study of a transitional millisecond pulsar candidate, and characterization of baseline dependent archiving tooling for MeerKAT. Our long term studies of PKS B1934-638, PKS B0407-65 indicate that these bandpass and flux calibrators are stable over multiple years. We also find that, especially at low frequencies in the UHF band, the population of sources surrounding these stellar Gigahertz Peaked Sources (GPS) can contribute to errors two to three orders of magnitude above desired bandpass calibration solution stability, if left unmodeled. We derive new new full sky models of these fields, currently in use by the MeerKAT Science Data Processor. We characterize the MeerKAT feed alignment using the refraction-driven linearly polarized thermal light from the Moon in order to derive a new model for the linear polarization of the stable quasar 3C286 down to 544 MHz. Part of this work includes characterization of ionospheric corrections using the International Global Navigation Satelite System Service and direct measurement of total electron content above the MeerKAT site using interchange data from the South African TrigNET service. We find that current commonly-employed techniques achieve corrections to ionospheric Faraday rotation no better than 1 rad m2. This is the main limitation on the accuracy of polarimetric observation using the MeerKAT array. We find that 3C286 intrinsically depolarizes at frequencies below 1 GHz, with an associated non-linear increase in the intrinsic source rotation measure. We present an improvement to workflows using the CUBICAL calibration framework, developed at Rhodes University. Modern radio interferometers presents a significant challenge to calibrate, often necessitating memory and computeintensive direction-dependent calibration towards many directions in order to improve the fidelity of radio images in order to meet scientific goals. We developed a framework to simplify the model prediction aspect of these direction-dependent calibration workflows using targeted faceting. Using our scheme users use models derived from the DDFACET imaging package and only need to provide lattices to mark regions of sky to which direction-dependent calibration solutions need to be solved for. This simplifies a laborious multi-step process in traditional calibration packages that need to be executed per direction. The approach is compared to an image-space corrective regime and incorporated into the VERMEERKAT end-to-end calibration framework for MeerKAT data. The improved direction-dependent calibration techniques were then applied in an analysis of the transitional millisecond pulsar candidate CXOU J110926.4-650224. The link between accreting binary systems (where emission is dominated by the synchrotron emission of relativistic jets from thermo-nuclear reaction onto the Neutron Star surface by the infalling matter) and binary radio pulsars is currently elusive. This is due to the lack of a large population of such transitional systems — only three confirmed transitional systems are known at the time of writing. It is thought that infalling matter effectively quenches the radio pulsar mechanism. Our candidate was found to be variable in the optical and the X-ray, with transitions between low, high and flaring states lasting anywhere from a tens of seconds to tens of minutes, seen in archival observations spanning nearly three decades. For the first time we detect low level synchrotron emission (_ 50 mJy beam1) coincident with this system using MeerKAT, including a flare within minutes of a flare detected in X-ray using the XMM-Newton observatory. Our analysis indicate that there is no clear anti-correlated behaviour between radio and X-ray state transitions in this system, unlike other candidate systems—indicating that such transitional systems may not exhibit homogenous behaviour. This suggests that the processes driving the X-ray mode-switching in this system are not directly linked to the processes responsible for emitting radio synchrotron radiation. Finally, we consider the problem of MeerKAT data archiving. We present a qualification analysis, using MeerKAT data, of the Rhodes University baseline-dependent archiving package XOVA, which can be used to compress and archive MeerKAT data in interchange standard-compliant format. The data rates from interferometric array radio telescopes, such as MeerKAT, grow as the square of the number of antennas in such an array. For the sake of reproducibility and future reanalysis it is important to archive calibrated visibility products. The degree to which calibrated visibility products can be compressed, by averaging, depends on the amount of smearing that can be tolerated at a fixed distance from the center of the images synthesized from these visibility products. This is, traditionally, set by the longest spacing in the interferometric array, with all other spacings averaged to the same integration and channelization as the longest spacing. We find that, using baseline-dependent averaging techniques – where averaging intervals are set per interferometric spacing – we can achieve space savings an order of magnitude better than traditional averaging approaches, with no appreciable loss of image fidelity when compared to traditional averaging approaches. , Thesis (PhD) -- Faculty of Science, Faculty of Science, Physics and Electronics, 2024
- Full Text:
- Date Issued: 2024-10-11
Metallophthalocyanines: versatile probes for microbial photoinactivation and for pollutant degradation as photocatalysts, both molecular or supported form
- Authors: Sindelo, Azole
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466614 , vital:76760 , DOI https://doi.org/10.21504/10962/466614
- Description: This thesis investigates the synthesie of metallophthalocyanines for potential use as photosensitizers in two applications: photodynamic antimicrobial chemotherapy and the photodegradation of organic pollutants. To achieve this, phthalocyanines with morpholine (substituted at alpha and beta position, to imine), ethyl and propyl pyrrolidine Schiff bases, asymmetrical mercaptobenzothiazole and morpholine substituents were synthesized for the first time. All nitrogen containing phthalocyanines were methylated to form cationic derivatives. Asymmetrical mercaptobenzothiazole were covalently linked to spherical and pyramidal zinc oxide nanoparticles, while the asymmetrical morpholine were conjugated to polyacrylonitrile (PAN) nanofibers, chitosan modified PAN and glass wool, while carboxylic acid containing phthalocyanines were also linked to glass wool. Various characterization techniques, including electronic spectroscopy, mass spectroscopy, nuclear magnetic resonance (NMR), Fourier-transform infrared (FT-IR), elemental analysis, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscope (SEM), and time-resolved fluorescence measurements were employed to characterize all the phthalocyanine composites. The research aimed to establish general trends in fluorescence quantum yields, triplet and singlet oxygen generation, photodegradation rates, and fluorescence and triplet state lifetimes of the complexes. Notably, the presence of zinc oxide nanoparticles increased the triplet quantum yield of phthalocyanines, however, the singlet oxygen quantum yield decreased. The study also examined the photodynamic inactivation of various planktonic cells and biofilms using all photosensitizers. The photodynamic antimicrobial chemotherapy activities were dose-dependent, and all cationic photosensitizers were highly effective in completely inactivating the microbes in both forms, as opposed to non-charged photosensitizers. For the supports, the chitosan modified PAN showed high efficacy due to improved hydrophilicity. Furthermore, the research was conducted on the photodegradation of 4-chlorophenol, methyl orange and methylene blue using Pc-anchored PAN and glass wool supports. The immobilized photosensitizers demonstrated a strong capacity for generating singlet oxygen in aqueous media, with the cationic Pc-PAN removing methylene blue more efficiently due to its adsorption and photodegradation abilities. All supports were recoverable, showing potential application for future use in the removal of microbes and organic pollutants. , Thesis (PhD) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Sindelo, Azole
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466614 , vital:76760 , DOI https://doi.org/10.21504/10962/466614
- Description: This thesis investigates the synthesie of metallophthalocyanines for potential use as photosensitizers in two applications: photodynamic antimicrobial chemotherapy and the photodegradation of organic pollutants. To achieve this, phthalocyanines with morpholine (substituted at alpha and beta position, to imine), ethyl and propyl pyrrolidine Schiff bases, asymmetrical mercaptobenzothiazole and morpholine substituents were synthesized for the first time. All nitrogen containing phthalocyanines were methylated to form cationic derivatives. Asymmetrical mercaptobenzothiazole were covalently linked to spherical and pyramidal zinc oxide nanoparticles, while the asymmetrical morpholine were conjugated to polyacrylonitrile (PAN) nanofibers, chitosan modified PAN and glass wool, while carboxylic acid containing phthalocyanines were also linked to glass wool. Various characterization techniques, including electronic spectroscopy, mass spectroscopy, nuclear magnetic resonance (NMR), Fourier-transform infrared (FT-IR), elemental analysis, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscope (SEM), and time-resolved fluorescence measurements were employed to characterize all the phthalocyanine composites. The research aimed to establish general trends in fluorescence quantum yields, triplet and singlet oxygen generation, photodegradation rates, and fluorescence and triplet state lifetimes of the complexes. Notably, the presence of zinc oxide nanoparticles increased the triplet quantum yield of phthalocyanines, however, the singlet oxygen quantum yield decreased. The study also examined the photodynamic inactivation of various planktonic cells and biofilms using all photosensitizers. The photodynamic antimicrobial chemotherapy activities were dose-dependent, and all cationic photosensitizers were highly effective in completely inactivating the microbes in both forms, as opposed to non-charged photosensitizers. For the supports, the chitosan modified PAN showed high efficacy due to improved hydrophilicity. Furthermore, the research was conducted on the photodegradation of 4-chlorophenol, methyl orange and methylene blue using Pc-anchored PAN and glass wool supports. The immobilized photosensitizers demonstrated a strong capacity for generating singlet oxygen in aqueous media, with the cationic Pc-PAN removing methylene blue more efficiently due to its adsorption and photodegradation abilities. All supports were recoverable, showing potential application for future use in the removal of microbes and organic pollutants. , Thesis (PhD) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
Mining MeerKAT data for minute to hour timescale transients and variable sources
- Authors: Gcilitshana, Sihle
- Date: 2024-10-11
- Subjects: MeerKAT , Astronomy Data processing , Radio astronomy , Pipelining (Electronics) , Active galactic nuclei
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464886 , vital:76554
- Description: In radio astronomy, minute-to-hour timescale transients and variable sources present an understudied population. We now have an unprecedented view of the transient radio sky due to the advent of new telescopes (such as the MeerKAT) with high instantaneous sensitivity, excellent snapshot imaging capabilities, and a large field of view. We can now probe into this population. This thesis presents the search for minute-to-hour timescale transient and variable sources in two of MeerKAT archival observations: the COSMOS and MACS J2140.2−2339 fields. The fields were observed for eight and five hours at the UHF band, respectively. We employed the PARROT transient and variable search pipeline currently being developed by the RATT group at Rhodes University. The pipeline’s input is a cross-calibrated measurement set, and its outputs are light curves extracted from all the sources in the restored image of the field. Using the light curves from the pipeline, we detected two variable sources in the COSMOS field, scintillating Active Galactic Nuclei (AGNs), which are most likely caused by the turbulent plasma in the interstellar medium. Due to persistent ionospheric diffraction, no variable sources were detected in the MACS J2140.2−2339 field, and no transients were detected in either field. The thesis also highlights areas where improvements to the PARROT pipeline can be implemented. , Thesis (MSc) -- Faculty of Science, Physics and Electronics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Gcilitshana, Sihle
- Date: 2024-10-11
- Subjects: MeerKAT , Astronomy Data processing , Radio astronomy , Pipelining (Electronics) , Active galactic nuclei
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464886 , vital:76554
- Description: In radio astronomy, minute-to-hour timescale transients and variable sources present an understudied population. We now have an unprecedented view of the transient radio sky due to the advent of new telescopes (such as the MeerKAT) with high instantaneous sensitivity, excellent snapshot imaging capabilities, and a large field of view. We can now probe into this population. This thesis presents the search for minute-to-hour timescale transient and variable sources in two of MeerKAT archival observations: the COSMOS and MACS J2140.2−2339 fields. The fields were observed for eight and five hours at the UHF band, respectively. We employed the PARROT transient and variable search pipeline currently being developed by the RATT group at Rhodes University. The pipeline’s input is a cross-calibrated measurement set, and its outputs are light curves extracted from all the sources in the restored image of the field. Using the light curves from the pipeline, we detected two variable sources in the COSMOS field, scintillating Active Galactic Nuclei (AGNs), which are most likely caused by the turbulent plasma in the interstellar medium. Due to persistent ionospheric diffraction, no variable sources were detected in the MACS J2140.2−2339 field, and no transients were detected in either field. The thesis also highlights areas where improvements to the PARROT pipeline can be implemented. , Thesis (MSc) -- Faculty of Science, Physics and Electronics, 2024
- Full Text:
- Date Issued: 2024-10-11
Modelling water quality dynamics by integrating PYWR, climate change, and land-cover scenarios: a case study in the Grootdraai Dam Catchment, Upper Vaal, South Africa
- Authors: Lazar, Sofia
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465000 , vital:76564
- Description: Water resource management faces global challenges in allocation, quality, and sustainability. Despite extensive focus on quantity, water quality remains neglected, especially in developing nations, owing to data scarcity and funding issues. Water quantity modelling is more advanced, leaving water quality modelling lagging, as it requires finer spatiotemporal scales. Global water quality models, including those used in South Africa, encounter complexity and data requirements, and some proprietary models limit access. In South Africa, a water quality model is integrated with the less accessible Water Resources Yield Model (WRYM). However, WRYM's spatial lumping may not suffice for water quality assessment, emphasising the need for improvement. This study aims to address the gap in water quality modelling by transitioning from lumped, proprietary, and monthly time-step models applied in South Africa to more spatially distributed, user-friendly, transparent, fast models and daily time-step models, using the Grootdraai Dam Catchment in the Upper Vaal as a study region. The study examines providing water quality simulation for various variables under different tested scenarios, including (i) land-use scenarios (e.g., urbanisation, industrialisation, population growth and expansion in agricultural areas); (ii) mixed scenarios (e.g., climate change, mine closure, and demand increase). The study proposed a framework shifting from the WRYM to a Python water resources (Pywr) model, linked with the Water Quality Systems Assessment Model (WQSAM) in the Grootdraai Dam Catchment. This integration, the Python water resources-Water Quality (Pywr-WQ) model, was developed by the Water Research centre (WRc) in the United Kingdom. The study employed multiple regression models to develop land-use models, the outcomes of which were integrated into the Pywr-WQ model for medium and long term land-use scenario predictions. The study resulted in the following findings: (1) significant patterns emerge concerning the impacts of urbanisation, mining, and agricultural expansion on water quality; (2) urban areas exhibit elevated levels of nitrate plus nitrite and ammonium over the long term associated with human activities and infrastructure development; (3) increased cultivation leads to heightened phosphate levels, indicative of agricultural runoff and potential high fertiliser usage, while the expansion of mining activities results in elevated concentrations of sulphate and Total Dissolved Solids (TDS), attributed to the discharge of mine effluents; (4) noticeable declines in the concentrations of TDS and sulphate are evident in the medium to long term when compared to the baseline simulations. However, the worst-case scenario (i.e., a 70% abstraction increase) exhibits elevated peaks and concentrations compared to scenarios with more probable demand increases (e.g., a 5% increase). , Thesis (MSc) -- Faculty of Science, Institute for Water Research, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Lazar, Sofia
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465000 , vital:76564
- Description: Water resource management faces global challenges in allocation, quality, and sustainability. Despite extensive focus on quantity, water quality remains neglected, especially in developing nations, owing to data scarcity and funding issues. Water quantity modelling is more advanced, leaving water quality modelling lagging, as it requires finer spatiotemporal scales. Global water quality models, including those used in South Africa, encounter complexity and data requirements, and some proprietary models limit access. In South Africa, a water quality model is integrated with the less accessible Water Resources Yield Model (WRYM). However, WRYM's spatial lumping may not suffice for water quality assessment, emphasising the need for improvement. This study aims to address the gap in water quality modelling by transitioning from lumped, proprietary, and monthly time-step models applied in South Africa to more spatially distributed, user-friendly, transparent, fast models and daily time-step models, using the Grootdraai Dam Catchment in the Upper Vaal as a study region. The study examines providing water quality simulation for various variables under different tested scenarios, including (i) land-use scenarios (e.g., urbanisation, industrialisation, population growth and expansion in agricultural areas); (ii) mixed scenarios (e.g., climate change, mine closure, and demand increase). The study proposed a framework shifting from the WRYM to a Python water resources (Pywr) model, linked with the Water Quality Systems Assessment Model (WQSAM) in the Grootdraai Dam Catchment. This integration, the Python water resources-Water Quality (Pywr-WQ) model, was developed by the Water Research centre (WRc) in the United Kingdom. The study employed multiple regression models to develop land-use models, the outcomes of which were integrated into the Pywr-WQ model for medium and long term land-use scenario predictions. The study resulted in the following findings: (1) significant patterns emerge concerning the impacts of urbanisation, mining, and agricultural expansion on water quality; (2) urban areas exhibit elevated levels of nitrate plus nitrite and ammonium over the long term associated with human activities and infrastructure development; (3) increased cultivation leads to heightened phosphate levels, indicative of agricultural runoff and potential high fertiliser usage, while the expansion of mining activities results in elevated concentrations of sulphate and Total Dissolved Solids (TDS), attributed to the discharge of mine effluents; (4) noticeable declines in the concentrations of TDS and sulphate are evident in the medium to long term when compared to the baseline simulations. However, the worst-case scenario (i.e., a 70% abstraction increase) exhibits elevated peaks and concentrations compared to scenarios with more probable demand increases (e.g., a 5% increase). , Thesis (MSc) -- Faculty of Science, Institute for Water Research, 2024
- Full Text:
- Date Issued: 2024-10-11
Music in everyday life: an exploration into the various uses of music among restaurant servers in Makhanda
- Authors: Dlamini, Andile Sakhile
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466161 , vital:76702
- Description: Inspired by the theory of practice in everyday life and symbolic interactionist perspectives, this thesis offers an account and analysis of findings from a qualitative study. It aimed to investigate the everyday uses of music among restaurant servers (individuals) in Makhanda, on an intra-level of analysis. It explored music’s role in individuals’ lives, and how music as an art is influential in constructing their individuality or self in society. Ten in-depth interviews were conducted through face-to-face collaboration and an audio recording device. It was evident that music plays various roles in people’s lives. Music, seemingly intertwined with everyday life permits individuals to diversly use music, for instance with tackling their emotions and mood, as an accompaniment to tasks or even a symbol that serves subjective meaning to self, essentially transforming the routinized mundanity of every day. , Thesis (MSocSci) -- Faculty of Humanities, Sociology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Dlamini, Andile Sakhile
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466161 , vital:76702
- Description: Inspired by the theory of practice in everyday life and symbolic interactionist perspectives, this thesis offers an account and analysis of findings from a qualitative study. It aimed to investigate the everyday uses of music among restaurant servers (individuals) in Makhanda, on an intra-level of analysis. It explored music’s role in individuals’ lives, and how music as an art is influential in constructing their individuality or self in society. Ten in-depth interviews were conducted through face-to-face collaboration and an audio recording device. It was evident that music plays various roles in people’s lives. Music, seemingly intertwined with everyday life permits individuals to diversly use music, for instance with tackling their emotions and mood, as an accompaniment to tasks or even a symbol that serves subjective meaning to self, essentially transforming the routinized mundanity of every day. , Thesis (MSocSci) -- Faculty of Humanities, Sociology, 2024
- Full Text:
- Date Issued: 2024-10-11
Navigating change: a critical analysis of social media’s role in shaping gender activists’ perspectives
- Authors: Dias, Sasha Elliot
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466128 , vital:76699
- Description: This research explores the unique challenges and opportunities that social media offers gender activists fighting for equality and social justice. It examines the negative and positive elements of social media, highlighting the ways it can be adopted to build communities, amplify voices, and advance social change in unique ways, but also the ways in which it can adversely contribute to existing power imbalances and inequalities. This research does not concentrate on any specific gender-based movement, but rather aims to understand how gender activists in South Africa have embraced social media in their local activism. The study followed a qualitative approach and collected the data through in-depth semi-structured interviews. It also followed a thematic framework in its analysis of the data collected from the interviews. The study found that, while online gender activism in South Africa faces challenges such as harassment and the digital gender divide, there is still progress in terms of community building and political engagement on social media. The findings suggest that, in spite of the challenges, social media can still be an important tool for advancing gender-based social justice in South Africa. This research made use of Counter-publics and Cyberfeminism as guiding theoretical frameworks. The theory of Counter-publics provides a valuable way of understanding how virtual groups emerge and challenge dominant societal norms and values. Cyberfeminism provides insight into how women have challenged contemporary inequalities through the adoption of technologies such as social media. As sub-components to Cyber-feminism, Intersectionality and Standpoint perspectives were used to understand how activists’ diverse identities and social positions influence their individual forms of activism. , Thesis (MSocSci) -- Faculty of Humanities, Sociology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Dias, Sasha Elliot
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466128 , vital:76699
- Description: This research explores the unique challenges and opportunities that social media offers gender activists fighting for equality and social justice. It examines the negative and positive elements of social media, highlighting the ways it can be adopted to build communities, amplify voices, and advance social change in unique ways, but also the ways in which it can adversely contribute to existing power imbalances and inequalities. This research does not concentrate on any specific gender-based movement, but rather aims to understand how gender activists in South Africa have embraced social media in their local activism. The study followed a qualitative approach and collected the data through in-depth semi-structured interviews. It also followed a thematic framework in its analysis of the data collected from the interviews. The study found that, while online gender activism in South Africa faces challenges such as harassment and the digital gender divide, there is still progress in terms of community building and political engagement on social media. The findings suggest that, in spite of the challenges, social media can still be an important tool for advancing gender-based social justice in South Africa. This research made use of Counter-publics and Cyberfeminism as guiding theoretical frameworks. The theory of Counter-publics provides a valuable way of understanding how virtual groups emerge and challenge dominant societal norms and values. Cyberfeminism provides insight into how women have challenged contemporary inequalities through the adoption of technologies such as social media. As sub-components to Cyber-feminism, Intersectionality and Standpoint perspectives were used to understand how activists’ diverse identities and social positions influence their individual forms of activism. , Thesis (MSocSci) -- Faculty of Humanities, Sociology, 2024
- Full Text:
- Date Issued: 2024-10-11
No way to escape: a crime fiction
- Authors: Dzanibe, Nkosivumile
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465923 , vital:76668
- Description: This study presents a model for science engagement that incorporates journalistic approaches. This model emerges from a project that aimed to create engagement and communication around a genetically modified sugar cane variety, developed by the South African Sugarcane Research Institute (SASRI). In this project, we engaged with small scale growers in the North and South Coast region of KwaZulu-Natal. This study’s methodology is based in action research and an iterative approach to science communication and engagement. It draws and reflects on an action research cycle captured through video documentary as a way to effectively and thoroughly collect, analyse and interpret data and produce through the case study. Based on this action research process a model for science engagement is proposed and reflected on and interrogated by scientists and science communicators through a focus group engagement (see model here as part of this thesis): https://drive.google.com/file/d/14UD1qd4fPcqIZrkESq5v2wgJ1Y2Q7hON/view?usp=sharing. I reflect, using video, on this model and how it incorporates principles and techniques for public engagement drawn from different approaches to journalism and communication studies, I argue that science engagement can benefit from drawing from journalistic approaches to public engagement such as those emerging from development communication, public journalism and development journalism. The submission of this thesis includes various other videos as part of the overall thesis. , Thesis (MA) -- Faculty of Humanities, Languages and Literatures, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Dzanibe, Nkosivumile
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465923 , vital:76668
- Description: This study presents a model for science engagement that incorporates journalistic approaches. This model emerges from a project that aimed to create engagement and communication around a genetically modified sugar cane variety, developed by the South African Sugarcane Research Institute (SASRI). In this project, we engaged with small scale growers in the North and South Coast region of KwaZulu-Natal. This study’s methodology is based in action research and an iterative approach to science communication and engagement. It draws and reflects on an action research cycle captured through video documentary as a way to effectively and thoroughly collect, analyse and interpret data and produce through the case study. Based on this action research process a model for science engagement is proposed and reflected on and interrogated by scientists and science communicators through a focus group engagement (see model here as part of this thesis): https://drive.google.com/file/d/14UD1qd4fPcqIZrkESq5v2wgJ1Y2Q7hON/view?usp=sharing. I reflect, using video, on this model and how it incorporates principles and techniques for public engagement drawn from different approaches to journalism and communication studies, I argue that science engagement can benefit from drawing from journalistic approaches to public engagement such as those emerging from development communication, public journalism and development journalism. The submission of this thesis includes various other videos as part of the overall thesis. , Thesis (MA) -- Faculty of Humanities, Languages and Literatures, 2024
- Full Text:
- Date Issued: 2024-10-11
Optimising Integrated Multitrophic Aquaculture (IMTA) on a South African abalone farm
- Authors: Falade, Abiodun Emmanuel
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466712 , vital:76772 , DOI https://doi.org/10.21504/10962/466712
- Description: The efficiency of fed nutrient utilisation in integrated multitrophic aquaculture (IMTA) system was evaluated on a South African abalone farm. On many commercial abalone farms in South Africa, Haliotis midae are fed a combination of pelleted feed and live macroalgae cultured downstream in abalone effluent. This production technique reduces the discharge of dissolved nutrients into the environment and improves farm productivity as unquantified proportion of the waste metabolites is captured as macroalgal biomass. However, the solid waste from abalone culture tanks remains unutilised and discharged to the coastal environments. Thus, there is scope to improve the dissolved nutrients removal efficiency of the macroalgae and to reduce the discharge of particulate nutrients using detritus waste extractive organisms. The present study aimed at the production and environmental performance of a shore-based abalone/macroalgae IMTA improving farm in South Africa by improving the nutrient utilisation efficiency of farmed abalone and seaweed and testing the waste solids removal potential of a sea cucumber species. Monoculture systems, where abalone and seaweed were cultured separately, both in fresh seawater (salinity: 35 g/L), were compared with an integrated culture system where the seaweed (Ulva lacinulata) was cultured downstream in the wastewater flowing from abalone tanks that were up-channel. Based on the findings from quantifying the performance of these production systems, methods to improve the nutrient utilisation and production efficiencies of the production systems were explored. These assessed methods included (1) the removal of abalone biodeposits by detritus extractive sea cucumber production, (2) evaluating the potential of farmed macroalgae as supplement in formulated diet, and (3) replacing mineral fertilisers with eco-friendly live microbial fertilisers for seaweed farming. Furthermore, the overall environmental performance of the two farm systems was quantified using a life cycle analysis methodology. Monitoring of the nutrient flows through the monoculture and IMTA systems revealed that the highest inputs of nutrients (nitrogen and phosphorus) into the abalone and seaweed culture tanks of the two production systems were abalone feed pellet (70-81%) and mineral fertilisers respectively (63-93%). About 48-51% of the nitrogen supplied from the feed was utilised by abalone in the IMTA and monoculture systems, while the remaining portion was lost as organic waste nitrogen on the production tank floor (20-30%) and as dissolved nitrogen in post-abalone tank effluent (30-36%). In the seaweed tanks receiving abalone effluent (IMTA), 69% of the dissolved nitrogen input was absorbed by cultured Ulva while 25% of the nitrogen was lost to the post-seaweed effluent which returned to the environment. However, in the monoculture system, 52% of the nitrogen from supplemented inorganic fertiliser was absorbed by cultured Ulva while ca. 46% of the nutrient was lost to coastal waters through the post-seaweed effluent. Moreover, while the feed accounted for ca. 74-78% input of the phosphorus in abalone of the two production systems, not more than 19% and 13% of this phosphorus was utilised by H. midae in the IMTA and monoculture systems respectively, while the largest portions were lost as organic waste in the sediment (34-45%) and dissolved waste phosphorus in the effluent (33-54%). In the seaweed tanks, a small portion (11-15%) of supplied phosphorus was removed by farmed Ulva while 77-89% was lost in the post-seaweed effluent discharged to coastal environment. The substitution of 50% mineral fertilisers with live microbial fertilisers during seaweed production significantly reduced the discharge of dissolved nitrogen and phosphorus from macroalgae raceways to coastal environment by 55 and 45% respectively, without impacting their growth, yield and nutrient compositions. A life cycle analysis of the measured energy and nutrients utilisation efficiency of these production systems was compiled, and the impacts of the inputs and outputs from each production system on the environment was assessed. The electrical energy input to abalone and seaweed tanks constituted the highest contribution to all assessed environmental impact categories for the two production systems, followed by the contributions from the nutrients supplied to farmed abalone (formulated diet) and seaweed (mineral fertilisers). The impact of these inputs on the environment was most evident on marine aquatic ecotoxicity being 2.11E+03 kg 1.4-DB eq and 4.43E+03 kg 1.4-DB eq for IMTA and monoculture systems respectively. The measured impact of seaweed aquaculture on the environment was reduced by 50-52% when Ulva was cultured in abalone effluent (IMTA) compared to culture in fresh seawater (monoculture). However, the input of chemical fertilisers in the two systems of cultivation resulted in similar eutrophication potentials (8.09 - 8.41E-02 kg PO4--- eq). To reduce the solid waste discharge from abalone tanks, and create an additional high-value crop, an endemic sea cucumber species (Neostichopus grammatus) was introduced on the floor of the abalone culture tanks in a pilot abalone/detritivore/macroalgae IMTA system. The sea cucumber utilised the biodeposits in abalone tanks as food which reduced organic solid discharge to the environment by 11%. However, the sea cucumbers displayed poor nutrient utilisation, a negative growth rate (- 0.59% day-1) and 49% weight loss by the end of the trial that was probably due to sub-optimal habitat conditions (lack of a sand substrate). The potential of including farmed Ulva (IMTA and monoculture) meal in pelleted feed for H. midae was evaluated as a means of improving farming efficiency and reducing the levels of fishmeal and soya in the pellet. In an initial trial, Ulva was included at 12% dry weight in commercial diet and fed to farmed H. midae for 244 d. The 12% inclusion of IMTA and monoculture Ulva resulted in poor feed conversion and nutrient utilisation by H. midae. In a follow-up trial which tested graded inclusion levels of Ulva meal (0.75, 1.50, 3.00, 6.00 and 12.00%), the growth rate and feed utilisation of H. midae was enhanced at a 0.75-6.00% inclusion level of the seaweed in the diet, while at a 6.00-12.00% inclusion level growth rates and feed conversion efficiencies decreased. Therefore, it is recommended that for sub-adult South African abalone, up to 6.00% IMTA Ulva meal can be included in the diet formulation without impacting their growth performance and nutrient utilisation efficiency negatively. This present study contributes to the understanding of the nutrient utilisation dynamics on integrated abalone farms in South Africa. The evidence from the different trials suggests the IMTA techniques tested could be adopted to improve the production performance and reduce the impact of abalone farming on the environment. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Falade, Abiodun Emmanuel
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466712 , vital:76772 , DOI https://doi.org/10.21504/10962/466712
- Description: The efficiency of fed nutrient utilisation in integrated multitrophic aquaculture (IMTA) system was evaluated on a South African abalone farm. On many commercial abalone farms in South Africa, Haliotis midae are fed a combination of pelleted feed and live macroalgae cultured downstream in abalone effluent. This production technique reduces the discharge of dissolved nutrients into the environment and improves farm productivity as unquantified proportion of the waste metabolites is captured as macroalgal biomass. However, the solid waste from abalone culture tanks remains unutilised and discharged to the coastal environments. Thus, there is scope to improve the dissolved nutrients removal efficiency of the macroalgae and to reduce the discharge of particulate nutrients using detritus waste extractive organisms. The present study aimed at the production and environmental performance of a shore-based abalone/macroalgae IMTA improving farm in South Africa by improving the nutrient utilisation efficiency of farmed abalone and seaweed and testing the waste solids removal potential of a sea cucumber species. Monoculture systems, where abalone and seaweed were cultured separately, both in fresh seawater (salinity: 35 g/L), were compared with an integrated culture system where the seaweed (Ulva lacinulata) was cultured downstream in the wastewater flowing from abalone tanks that were up-channel. Based on the findings from quantifying the performance of these production systems, methods to improve the nutrient utilisation and production efficiencies of the production systems were explored. These assessed methods included (1) the removal of abalone biodeposits by detritus extractive sea cucumber production, (2) evaluating the potential of farmed macroalgae as supplement in formulated diet, and (3) replacing mineral fertilisers with eco-friendly live microbial fertilisers for seaweed farming. Furthermore, the overall environmental performance of the two farm systems was quantified using a life cycle analysis methodology. Monitoring of the nutrient flows through the monoculture and IMTA systems revealed that the highest inputs of nutrients (nitrogen and phosphorus) into the abalone and seaweed culture tanks of the two production systems were abalone feed pellet (70-81%) and mineral fertilisers respectively (63-93%). About 48-51% of the nitrogen supplied from the feed was utilised by abalone in the IMTA and monoculture systems, while the remaining portion was lost as organic waste nitrogen on the production tank floor (20-30%) and as dissolved nitrogen in post-abalone tank effluent (30-36%). In the seaweed tanks receiving abalone effluent (IMTA), 69% of the dissolved nitrogen input was absorbed by cultured Ulva while 25% of the nitrogen was lost to the post-seaweed effluent which returned to the environment. However, in the monoculture system, 52% of the nitrogen from supplemented inorganic fertiliser was absorbed by cultured Ulva while ca. 46% of the nutrient was lost to coastal waters through the post-seaweed effluent. Moreover, while the feed accounted for ca. 74-78% input of the phosphorus in abalone of the two production systems, not more than 19% and 13% of this phosphorus was utilised by H. midae in the IMTA and monoculture systems respectively, while the largest portions were lost as organic waste in the sediment (34-45%) and dissolved waste phosphorus in the effluent (33-54%). In the seaweed tanks, a small portion (11-15%) of supplied phosphorus was removed by farmed Ulva while 77-89% was lost in the post-seaweed effluent discharged to coastal environment. The substitution of 50% mineral fertilisers with live microbial fertilisers during seaweed production significantly reduced the discharge of dissolved nitrogen and phosphorus from macroalgae raceways to coastal environment by 55 and 45% respectively, without impacting their growth, yield and nutrient compositions. A life cycle analysis of the measured energy and nutrients utilisation efficiency of these production systems was compiled, and the impacts of the inputs and outputs from each production system on the environment was assessed. The electrical energy input to abalone and seaweed tanks constituted the highest contribution to all assessed environmental impact categories for the two production systems, followed by the contributions from the nutrients supplied to farmed abalone (formulated diet) and seaweed (mineral fertilisers). The impact of these inputs on the environment was most evident on marine aquatic ecotoxicity being 2.11E+03 kg 1.4-DB eq and 4.43E+03 kg 1.4-DB eq for IMTA and monoculture systems respectively. The measured impact of seaweed aquaculture on the environment was reduced by 50-52% when Ulva was cultured in abalone effluent (IMTA) compared to culture in fresh seawater (monoculture). However, the input of chemical fertilisers in the two systems of cultivation resulted in similar eutrophication potentials (8.09 - 8.41E-02 kg PO4--- eq). To reduce the solid waste discharge from abalone tanks, and create an additional high-value crop, an endemic sea cucumber species (Neostichopus grammatus) was introduced on the floor of the abalone culture tanks in a pilot abalone/detritivore/macroalgae IMTA system. The sea cucumber utilised the biodeposits in abalone tanks as food which reduced organic solid discharge to the environment by 11%. However, the sea cucumbers displayed poor nutrient utilisation, a negative growth rate (- 0.59% day-1) and 49% weight loss by the end of the trial that was probably due to sub-optimal habitat conditions (lack of a sand substrate). The potential of including farmed Ulva (IMTA and monoculture) meal in pelleted feed for H. midae was evaluated as a means of improving farming efficiency and reducing the levels of fishmeal and soya in the pellet. In an initial trial, Ulva was included at 12% dry weight in commercial diet and fed to farmed H. midae for 244 d. The 12% inclusion of IMTA and monoculture Ulva resulted in poor feed conversion and nutrient utilisation by H. midae. In a follow-up trial which tested graded inclusion levels of Ulva meal (0.75, 1.50, 3.00, 6.00 and 12.00%), the growth rate and feed utilisation of H. midae was enhanced at a 0.75-6.00% inclusion level of the seaweed in the diet, while at a 6.00-12.00% inclusion level growth rates and feed conversion efficiencies decreased. Therefore, it is recommended that for sub-adult South African abalone, up to 6.00% IMTA Ulva meal can be included in the diet formulation without impacting their growth performance and nutrient utilisation efficiency negatively. This present study contributes to the understanding of the nutrient utilisation dynamics on integrated abalone farms in South Africa. The evidence from the different trials suggests the IMTA techniques tested could be adopted to improve the production performance and reduce the impact of abalone farming on the environment. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2024
- Full Text:
- Date Issued: 2024-10-11