Exploring the psychological and emotional understanding of Amagqirha within the Eastern Cape province, South Africa
- Authors: Ncapayi, Abongile
- Date: 2023-12
- Subjects: traditional healers , Indigenous Knowledge , Cultural religion
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62947 , vital:73074
- Description: Indigenous knowledge systems influence mental health understanding and treatments. Amongst the Xhosa’s (amaXhosa), a person may receive a ‘calling’ from the ancestors, usually associated with symptoms that would be characterized as a mental illness. However, the symptoms experienced during the calling, usually dissipate once training has been received. One of the categories within traditional healers are amagqirha, also known as diviners. These are individuals who receive the ‘calling’. Thereafter, they undergo extensive training and become blessed with clairvoyant “powers” to divine and act as mediators between the living and the dead. This study aimed to explore the psychological and emotional understanding of amagqirha of the Xhosa culture, within the Eastern Cape, South Africa. In doing so, the study centralizes the experiences of individuals within cultural spaces, allowing for commentary on the psychological and emotional understanding of the amagqirha. Furthermore, this study focused on the work that amagqirha do in communities and how this ultimately affects them. This study sought to understand the experiences and perceptions of the individuals who are affected by this ‘calling’. The researcher employed a qualitative method with an exploratory-descriptive research design. Ten participants were recruited by utilizing a purposive snowball sampling strategy. Data was collected using a semi-structured interview due to the sensitivity of the demographic of the study. Ethics were adhered to. Additionally, trustworthiness was guided by Lincoln and Guba’s (1985) four constructs: credibility, dependability, transferability, and confirmability. Thematic analysis was used as a means of data analysis, as presented by Braun and Clarke (2006). The themes identified were: The collateral damage/profuse repercussions cast upon by the ancestors due to inaction (either by them or those that case before them), the severity of the emotional and psychological effects is equally prevalent prior and during their journey of vi ubugqirha, methods that may assist in alleviating the emotional and psychological symptoms, understanding of mental health, awareness of their own mental health status, and help-seeking (psychological services). The main findings suggested that there is a general understanding of the term ‘mental health’ amongst amagqirha. Additionally, the findings revealed that amagqirha experienced emotional and psychological symptoms/effects, prior to and during the journey of ubugqirha - these were due to the lack of understanding and fear. Furthermore, the findings suggesting that amagqirha embarked on various help-seeking measures, i.e., seeking psychological services or leaning into seeking guidance from their ancestors. However, they were met with barriers as well, i.e., finding a mental health practitioner with awareness on African spirituality, and dealing with the stigma that comes with help-seeking. , Thesis (Ma) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Ncapayi, Abongile
- Date: 2023-12
- Subjects: traditional healers , Indigenous Knowledge , Cultural religion
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62947 , vital:73074
- Description: Indigenous knowledge systems influence mental health understanding and treatments. Amongst the Xhosa’s (amaXhosa), a person may receive a ‘calling’ from the ancestors, usually associated with symptoms that would be characterized as a mental illness. However, the symptoms experienced during the calling, usually dissipate once training has been received. One of the categories within traditional healers are amagqirha, also known as diviners. These are individuals who receive the ‘calling’. Thereafter, they undergo extensive training and become blessed with clairvoyant “powers” to divine and act as mediators between the living and the dead. This study aimed to explore the psychological and emotional understanding of amagqirha of the Xhosa culture, within the Eastern Cape, South Africa. In doing so, the study centralizes the experiences of individuals within cultural spaces, allowing for commentary on the psychological and emotional understanding of the amagqirha. Furthermore, this study focused on the work that amagqirha do in communities and how this ultimately affects them. This study sought to understand the experiences and perceptions of the individuals who are affected by this ‘calling’. The researcher employed a qualitative method with an exploratory-descriptive research design. Ten participants were recruited by utilizing a purposive snowball sampling strategy. Data was collected using a semi-structured interview due to the sensitivity of the demographic of the study. Ethics were adhered to. Additionally, trustworthiness was guided by Lincoln and Guba’s (1985) four constructs: credibility, dependability, transferability, and confirmability. Thematic analysis was used as a means of data analysis, as presented by Braun and Clarke (2006). The themes identified were: The collateral damage/profuse repercussions cast upon by the ancestors due to inaction (either by them or those that case before them), the severity of the emotional and psychological effects is equally prevalent prior and during their journey of vi ubugqirha, methods that may assist in alleviating the emotional and psychological symptoms, understanding of mental health, awareness of their own mental health status, and help-seeking (psychological services). The main findings suggested that there is a general understanding of the term ‘mental health’ amongst amagqirha. Additionally, the findings revealed that amagqirha experienced emotional and psychological symptoms/effects, prior to and during the journey of ubugqirha - these were due to the lack of understanding and fear. Furthermore, the findings suggesting that amagqirha embarked on various help-seeking measures, i.e., seeking psychological services or leaning into seeking guidance from their ancestors. However, they were met with barriers as well, i.e., finding a mental health practitioner with awareness on African spirituality, and dealing with the stigma that comes with help-seeking. , Thesis (Ma) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12
Exploring university level admissions decision-making based on access testing and undergraduate admissions variables
- Authors: Oakes, Elizabeth
- Date: 2023-12
- Subjects: decision-making , Social-Judgement Theory , Cognitive-Continuum TheoryLens Model Equation
- Language: English
- Type: Doctoral's theses , text
- Identifier: http://hdl.handle.net/10948/62969 , vital:73078
- Description: Decision-making is an essential everyday cognitive function. How people go about making judgements and decisions is difficult to pin down. The reason for this lies in the inherent nature of decision-making, which is uncertain and variable because decision-making is a human cognitive process that is context-dependent. However, the body of research on judgement and decision-making (JDM) is concerned with describing what people are 'actually' thinking, when they make decisions or judgements. This study applied the descriptive theories of the Social-Judgement Theory (SJT) and the Cognitive-Continuum Theory (CCT), in order to understand decision-making in an undergraduate, entry-level admission decision-making context, in which decision-makers used access testing and school results, to make admission decisions at Nelson Mandela University. The sample consisted of four consultants from the Centre for Access Assessment and Research (CAAR) who volunteered to participate in the study. While the sample was small, it was nonetheless deemed to be adequate as 57% of the consultants at CAAR were included in the sample. Using the SJT methodological approach, an experiment was conducted to mirror the real-life context of decision-making at CAAR. As CAAR consultants were used to test, and school results being presented on a profile when they made decisions, a sample of 120 of these was drawn from a repository, with 60 of them requiring decisions for degree admission (to B Com Accounting) and 60 for diploma admission (to the Diploma in Accountancy). Ten degree and 10 diploma profiles were duplicated to check for consistency in decision-making. As SJT suggests restricting the number of cues used, a process was instituted to identify the cues perceived to be used most frequently to make decisions at CAAR. This resulted in 5 cues being included on the cue profile. In Phase 1 of the experiment the CAAR consultants made admission decisions using a familiar cue profile in terms of how the information was presented visually and numerically. In phase 2 the information was presented using a different visual format, which was more closely aligned to the intuitive decision-making mode that most consultants used. A 2 x 2 within-subjects experimental design was thus employed with two independent variables, namely, profile type and program type. Descriptive statistics and correlational and regression analyses were used to describe the judgement policies of the consultants in terms of the time taken, the difficulty ratings, and the cue use and its importance). The indices of the Lens Model Equation (LME) of SJT were used to describe the decision-achievement levels, and the Task-Continuum Index (TCI) was computed to describe which cognitive modes were used. xvii The results revealed that decision-makers have unique, varied, and changeable judgement policies, with regard to the time taken, the perception of difficulty, and the decision outcomes and had a tendency to rely more on the school results, while the regression models derived indicated that test results made a stronger contribution to the decision outcome. The consultants found degree decisions easier than diploma decisions, and the consultants perceived the contribution and weighting of the cues somewhat differently, once the format of the cue profile had changed in Phase 2, although they made decisions more quickly in Phase 2. The decision-makers also displayed individualised patterns of decision achievement that differed for degree and diploma programs. Furthermore, in terms of the cognitive mode, decision-makers were thinking quasi-rationally and they largely used the cognitive modes of computer modelling or expert judgement. Thus, by synergistically using the two theories of JDM, the researcher was able to determine baseline information for understanding decision- making in an admission context. Furthermore, suggestions were made in terms of the nature of the feedback and training that could be provided to decision-makers to enhance their future decision-making. Suggestions were also made regarding how the methodology used and findings of this study could be applied in other contexts, such as when training students in psychological assessment. , Thesis (Ma) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Oakes, Elizabeth
- Date: 2023-12
- Subjects: decision-making , Social-Judgement Theory , Cognitive-Continuum TheoryLens Model Equation
- Language: English
- Type: Doctoral's theses , text
- Identifier: http://hdl.handle.net/10948/62969 , vital:73078
- Description: Decision-making is an essential everyday cognitive function. How people go about making judgements and decisions is difficult to pin down. The reason for this lies in the inherent nature of decision-making, which is uncertain and variable because decision-making is a human cognitive process that is context-dependent. However, the body of research on judgement and decision-making (JDM) is concerned with describing what people are 'actually' thinking, when they make decisions or judgements. This study applied the descriptive theories of the Social-Judgement Theory (SJT) and the Cognitive-Continuum Theory (CCT), in order to understand decision-making in an undergraduate, entry-level admission decision-making context, in which decision-makers used access testing and school results, to make admission decisions at Nelson Mandela University. The sample consisted of four consultants from the Centre for Access Assessment and Research (CAAR) who volunteered to participate in the study. While the sample was small, it was nonetheless deemed to be adequate as 57% of the consultants at CAAR were included in the sample. Using the SJT methodological approach, an experiment was conducted to mirror the real-life context of decision-making at CAAR. As CAAR consultants were used to test, and school results being presented on a profile when they made decisions, a sample of 120 of these was drawn from a repository, with 60 of them requiring decisions for degree admission (to B Com Accounting) and 60 for diploma admission (to the Diploma in Accountancy). Ten degree and 10 diploma profiles were duplicated to check for consistency in decision-making. As SJT suggests restricting the number of cues used, a process was instituted to identify the cues perceived to be used most frequently to make decisions at CAAR. This resulted in 5 cues being included on the cue profile. In Phase 1 of the experiment the CAAR consultants made admission decisions using a familiar cue profile in terms of how the information was presented visually and numerically. In phase 2 the information was presented using a different visual format, which was more closely aligned to the intuitive decision-making mode that most consultants used. A 2 x 2 within-subjects experimental design was thus employed with two independent variables, namely, profile type and program type. Descriptive statistics and correlational and regression analyses were used to describe the judgement policies of the consultants in terms of the time taken, the difficulty ratings, and the cue use and its importance). The indices of the Lens Model Equation (LME) of SJT were used to describe the decision-achievement levels, and the Task-Continuum Index (TCI) was computed to describe which cognitive modes were used. xvii The results revealed that decision-makers have unique, varied, and changeable judgement policies, with regard to the time taken, the perception of difficulty, and the decision outcomes and had a tendency to rely more on the school results, while the regression models derived indicated that test results made a stronger contribution to the decision outcome. The consultants found degree decisions easier than diploma decisions, and the consultants perceived the contribution and weighting of the cues somewhat differently, once the format of the cue profile had changed in Phase 2, although they made decisions more quickly in Phase 2. The decision-makers also displayed individualised patterns of decision achievement that differed for degree and diploma programs. Furthermore, in terms of the cognitive mode, decision-makers were thinking quasi-rationally and they largely used the cognitive modes of computer modelling or expert judgement. Thus, by synergistically using the two theories of JDM, the researcher was able to determine baseline information for understanding decision- making in an admission context. Furthermore, suggestions were made in terms of the nature of the feedback and training that could be provided to decision-makers to enhance their future decision-making. Suggestions were also made regarding how the methodology used and findings of this study could be applied in other contexts, such as when training students in psychological assessment. , Thesis (Ma) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12
Field mapping and geochemistry of lower Jurassic sediments and volcanics of the upper Karoo supergroup near Ha Mosi, Lesotho mountains
- Authors: Valashiya, Khaya
- Date: 2023-12
- Subjects: Sediments (Geology) -- South Africa -- karoo basin , Geochemistry , Geological mapping
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62687 , vital:72925
- Description: Geological mapping in the Lesotho-Drakensberg Mountains spans over 100 years with du Toit and Stockley being the major contributors to the published maps and to the understanding of emplacement of the Karoo Large Igneous Province (KLIP) in the countries of South Africa and Lesotho. Despite the detailed previous work, there remains limited data on paleoenvironmental changes at the contact between the sedimentary and volcanic sequences of the upper Karoo Supergroup. This study aims to map the lithostratigraphic boundaries, volcano-sedimentary facies and faults near Ha Mosi in southern Lesotho. A total 48 rock samples were collected for petrography, XRF and ICP-MS analyses. The new results were used to characterize the local chemostratigraphy and to propose new regional correlations across Lesotho and South Africa. In this thesis, eight lithostratigraphic units were defined with a total thickness of 550 m. The first two units (Units 1 and 2) comprise massive and bedded sandstones, interpreted as possible floodplain and ephemeral lacustrine deposits; these are ascribed to the upper Stormberg Group. These units are unconformably overlain by locally preserved thin basaltic (Unit 3) flows that are characterised by high Zr/Nb and Zr/Y ratios; and low Ti/Zr and P/Zr ratios similar to the Golden Gate Unit of the Drakensberg Group. The lava flows are overlain by bedded sandstone ascribed to Unit 4 and volcaniclastic breccia ascribed to Units 5 and 6. Unit 6 consists of a monolithic breccia that is composed of angular sandstone clasts similar to those of the underlying Stormberg Group. The monolithic breccia transitions upwards into a massive megaclastic clast-supported volcanic breccia, which consists of angular to sub-rounded basaltic and doleritic boulders. Petrified wood fragments are found within the megaclastic breccia, indicating the presence of vegetation during deposition and enhanced preservation. Unit 6 laterally grades into Unit 5, which is characterised by poorly bedded breccia composed of angular sandstone, mudstone clasts with minor basaltic and doleritic clasts and, breccia intraclasts. The breccia units are often associated with reworked sediments interpreted to be deposited by fluvial systems. The breccia is conformably overlain by basaltic lava flows (Unit 8) characterised by high Ti/Zr and P/Zr ratios and moderate to low Zr/Y and Zr/Nb ratios compared to the Unit 3 lavas and is similar to that of the Sani Pass Unit of the Drakensberg Group. The basaltic sequences in the Ha Mosi studied area preserve both pahoehoe textures and pillow lavas, indicating subaerial and subaqueous volcanism. The studied lithologies are intruded by gabbro and dolerites of the Karoo Dolerite Suite at 183 Ma. This stratigraphy records the transition from sedimentation in the Karoo Basin through to a dominantly volcanic succession, which has importance in terms of the Toarcian extinction at ca. 182 Ma. Mapped faults and associated fractures are orientated predominantly NW-SE with the hanging walls moved maximum 80 m to the south. The different dykes and fault structures possibly relate to the Weddel Triple Junction that developed during the Early Jurassic break up of Gondwana, between 200 and 180 Ma. The mapped lavas show that the magma source was a chemically heterogenous mantle that was subjected to different degrees of partial melting, with the introduction of small-scale chemical heterogeneities. The geodynamic setting is comparable to the Afar Triangle of north-east Africa where active tectonics created a large-scale NW-SE orientated fault system in response to crustal thinning and rifting. In both the Afar and Lesotho, vertical movements created lowlands that allow for the preservation of volcanic breccia and basalts with pillow lavas. These findings show that existing geological models in the Drakensberg-Lesotho Mountains can be improved upon detailed field mapping and geochemistry. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Valashiya, Khaya
- Date: 2023-12
- Subjects: Sediments (Geology) -- South Africa -- karoo basin , Geochemistry , Geological mapping
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62687 , vital:72925
- Description: Geological mapping in the Lesotho-Drakensberg Mountains spans over 100 years with du Toit and Stockley being the major contributors to the published maps and to the understanding of emplacement of the Karoo Large Igneous Province (KLIP) in the countries of South Africa and Lesotho. Despite the detailed previous work, there remains limited data on paleoenvironmental changes at the contact between the sedimentary and volcanic sequences of the upper Karoo Supergroup. This study aims to map the lithostratigraphic boundaries, volcano-sedimentary facies and faults near Ha Mosi in southern Lesotho. A total 48 rock samples were collected for petrography, XRF and ICP-MS analyses. The new results were used to characterize the local chemostratigraphy and to propose new regional correlations across Lesotho and South Africa. In this thesis, eight lithostratigraphic units were defined with a total thickness of 550 m. The first two units (Units 1 and 2) comprise massive and bedded sandstones, interpreted as possible floodplain and ephemeral lacustrine deposits; these are ascribed to the upper Stormberg Group. These units are unconformably overlain by locally preserved thin basaltic (Unit 3) flows that are characterised by high Zr/Nb and Zr/Y ratios; and low Ti/Zr and P/Zr ratios similar to the Golden Gate Unit of the Drakensberg Group. The lava flows are overlain by bedded sandstone ascribed to Unit 4 and volcaniclastic breccia ascribed to Units 5 and 6. Unit 6 consists of a monolithic breccia that is composed of angular sandstone clasts similar to those of the underlying Stormberg Group. The monolithic breccia transitions upwards into a massive megaclastic clast-supported volcanic breccia, which consists of angular to sub-rounded basaltic and doleritic boulders. Petrified wood fragments are found within the megaclastic breccia, indicating the presence of vegetation during deposition and enhanced preservation. Unit 6 laterally grades into Unit 5, which is characterised by poorly bedded breccia composed of angular sandstone, mudstone clasts with minor basaltic and doleritic clasts and, breccia intraclasts. The breccia units are often associated with reworked sediments interpreted to be deposited by fluvial systems. The breccia is conformably overlain by basaltic lava flows (Unit 8) characterised by high Ti/Zr and P/Zr ratios and moderate to low Zr/Y and Zr/Nb ratios compared to the Unit 3 lavas and is similar to that of the Sani Pass Unit of the Drakensberg Group. The basaltic sequences in the Ha Mosi studied area preserve both pahoehoe textures and pillow lavas, indicating subaerial and subaqueous volcanism. The studied lithologies are intruded by gabbro and dolerites of the Karoo Dolerite Suite at 183 Ma. This stratigraphy records the transition from sedimentation in the Karoo Basin through to a dominantly volcanic succession, which has importance in terms of the Toarcian extinction at ca. 182 Ma. Mapped faults and associated fractures are orientated predominantly NW-SE with the hanging walls moved maximum 80 m to the south. The different dykes and fault structures possibly relate to the Weddel Triple Junction that developed during the Early Jurassic break up of Gondwana, between 200 and 180 Ma. The mapped lavas show that the magma source was a chemically heterogenous mantle that was subjected to different degrees of partial melting, with the introduction of small-scale chemical heterogeneities. The geodynamic setting is comparable to the Afar Triangle of north-east Africa where active tectonics created a large-scale NW-SE orientated fault system in response to crustal thinning and rifting. In both the Afar and Lesotho, vertical movements created lowlands that allow for the preservation of volcanic breccia and basalts with pillow lavas. These findings show that existing geological models in the Drakensberg-Lesotho Mountains can be improved upon detailed field mapping and geochemistry. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Finite difference methods for Burgers-Huxley equation and biofilm formation
- Authors: Tijani, Yusuf Olatunji
- Date: 2023-12
- Subjects: Burgers equation , Terrestrial heat flow , Applied mathematics
- Language: English
- Type: Doctorial theses , text
- Identifier: http://hdl.handle.net/10948/62732 , vital:72934
- Description: In this thesis, we constructed some versions of finite difference scheme for the Burgers-Huxley equation and for a set of partial differential equations (PDEs) arising in biofilm formation. The Burgers-Huxley equation serves as a fundamental model that describes the interaction between reaction mechanisms, convection effects, and diffusion transport. It has applications in the study of wave mechanics, population dynamics, physiology, fluid mechanics to list but a few. The study of biofilm formation is becoming increasingly important due to micro-organisms (i.e. bacteria) forming a protected mode from the host defense mechanism which may result in alteration in the host gene transcription and growth rate. Applications can be found useful in the treatment of bacterial infections, contamination of foods and water quality. We designed two nonstandard finite difference and two exponential finite difference schemes for the Burgers-Huxley equation. Numerical experiments with six cases and in three different regimes were studied. We show that the nonstandard scheme preserves the properties of the continuous equation which include positivity and boundedness. The stability region of the explicit exponential scheme was obtained and we outlined the algorithm for the implicit exponential scheme. The performance of the four schemes are compared in regard to absolute error, relative error, L1 and L∞ norms. For a singularly perturbed Burgers-Huxley equation, a novel nonstandard finite difference technique is constructed. It is demonstrated numerically that the NSFD scheme outperforms the classical scheme by comparing maximum pointwise errors and rate of convergence. We then solved the 2D Burgers-Huxley equation using four novel nonstandard finite difference schemes (NSFD1, NSFD2, NSFD3 and NSFD4). The numerical profiles from NSFD1 and NSFD2 exhibit some deviation from the exact profile. Our quest for a better performing scheme led to the modification of NSFD1 using the remainder effect technique. NSFD4 was designed by employing the time splitting approach. All the schemes preserve the properties of the continuous model (positivity and boundedness). The performance of all the schemes are analysed. We construct three nonstandard finite difference schemes for the equations modelling biomass equation and coupled substrate-biomass system of equations respectively. We checked the accuracy of our scheme by the conservation of physical properties (positivity, boundedness, biofilm formation and annihilation) since an analytical solution is not available. We show the instability, lack of conservation of physical properties by the classical scheme. Our proposed scheme shows good performance when compared with other results in the literature. The results here give more insight into the benefits of the nonstandard finite difference approximations. , Thesis (DPhil) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics , 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Tijani, Yusuf Olatunji
- Date: 2023-12
- Subjects: Burgers equation , Terrestrial heat flow , Applied mathematics
- Language: English
- Type: Doctorial theses , text
- Identifier: http://hdl.handle.net/10948/62732 , vital:72934
- Description: In this thesis, we constructed some versions of finite difference scheme for the Burgers-Huxley equation and for a set of partial differential equations (PDEs) arising in biofilm formation. The Burgers-Huxley equation serves as a fundamental model that describes the interaction between reaction mechanisms, convection effects, and diffusion transport. It has applications in the study of wave mechanics, population dynamics, physiology, fluid mechanics to list but a few. The study of biofilm formation is becoming increasingly important due to micro-organisms (i.e. bacteria) forming a protected mode from the host defense mechanism which may result in alteration in the host gene transcription and growth rate. Applications can be found useful in the treatment of bacterial infections, contamination of foods and water quality. We designed two nonstandard finite difference and two exponential finite difference schemes for the Burgers-Huxley equation. Numerical experiments with six cases and in three different regimes were studied. We show that the nonstandard scheme preserves the properties of the continuous equation which include positivity and boundedness. The stability region of the explicit exponential scheme was obtained and we outlined the algorithm for the implicit exponential scheme. The performance of the four schemes are compared in regard to absolute error, relative error, L1 and L∞ norms. For a singularly perturbed Burgers-Huxley equation, a novel nonstandard finite difference technique is constructed. It is demonstrated numerically that the NSFD scheme outperforms the classical scheme by comparing maximum pointwise errors and rate of convergence. We then solved the 2D Burgers-Huxley equation using four novel nonstandard finite difference schemes (NSFD1, NSFD2, NSFD3 and NSFD4). The numerical profiles from NSFD1 and NSFD2 exhibit some deviation from the exact profile. Our quest for a better performing scheme led to the modification of NSFD1 using the remainder effect technique. NSFD4 was designed by employing the time splitting approach. All the schemes preserve the properties of the continuous model (positivity and boundedness). The performance of all the schemes are analysed. We construct three nonstandard finite difference schemes for the equations modelling biomass equation and coupled substrate-biomass system of equations respectively. We checked the accuracy of our scheme by the conservation of physical properties (positivity, boundedness, biofilm formation and annihilation) since an analytical solution is not available. We show the instability, lack of conservation of physical properties by the classical scheme. Our proposed scheme shows good performance when compared with other results in the literature. The results here give more insight into the benefits of the nonstandard finite difference approximations. , Thesis (DPhil) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics , 2023
- Full Text:
- Date Issued: 2023-12
Functional traits and potential physical drivers of offshore benthic epifauna on the west and south coast of South Africa
- Van Stavel, Jordan, Morris, Tamaryn
- Authors: Van Stavel, Jordan , Morris, Tamaryn
- Date: 2023-12
- Subjects: Marine ecology , Marine biology -- South Africa , Oceanography -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62698 , vital:72931
- Description: Offshore benthic ecosystems (> 200 m depth) are challenging to access and remain poorly studied globally. Epifaunal invertebrates comprise a critical trophic level in benthic ecosystems and can serve as indicators of the overall health and functioning. There is limited knowledge of South Africa’s offshore marine environment and benthic ecosystem functioning due to limitations in funding, resources, and the lack of suitable science-based monitoring tools which are vital for sustainable management into the future. The aim of this research was to improve the understanding of epifaunal functioning as well as their potential physical drivers in 13 South African offshore biogeographic ecotypes. The objectives of this study were threefold: 1) to investigate the functional composition of benthic epifauna from 13 biogeographic ecotypes, 2) to quantify the Functional Diversity (FD) associated with epifaunal traits between the different assemblages (i.e. biogeographic ecotypes), and 3) to evaluate the relationship between physical variables and epifaunal functional traits at the biogeographic ecotype level. Biological trait-based approaches were applied to a subset of 80 benthic epifaunal species collected from 909 offshore stations along the west and south coasts of South Africa. Nine biological traits (associated with life history, morphology and behavioural characteristics exhibited by each species) were classified into 39 modalities and weighted with biomass. Community Weighted Means (CWMs) were used to evaluate the benthic epifaunal functional trait composition of the 13 biogeographic ecotypes. Functional composition across the 13 ecotype assemblages on the west and south coast appeared to be dominated by species with similar trait compositions, such as large, long-lived, surface crawling/burrowing/filter-feeding epifauna with medium to no mobility, however, their percentage of contribution to trait expression (CWMs) was higher on the west coast. Functional diversity indices (alpha and beta) showed higher overall FD for west coast ecotypes, with most ecotypes on the continental shelf (except slopes and canyons) being significantly different (p<0.05) from ecotypes on the south coast. The global RLQ (three-table co-inertia) test did not reveal a significant relationship between biomass and physical variables or between biomass and traits (p>0.05). The fourth-corner method was used to test the significance of individual traitenvironment relationships. The fourth-corner results were similar overall to the RLQ analysis, revealing that three physical variables (temperature, depth, and fluorescence) were significantly correlated to two trait modalities belonging to the feeding mode filter-feeders (FM1) and scavengers (FM5). Scavengers were positively correlated with depth and negatively with temperature, while filter-feeders were positively correlated with fluorescence levels. This indicated that the presence of scavenging epifauna increased with a decrease in temperature and an increase in depth. While a positive significant correlation between filter-feeders and fluorescence suggested their potential tolerance or preference for environmental conditions with high levels of fluorescence. This research was the first such study to explore the functional composition and diversity of benthic epifauna and their relationship with potential physical drivers in offshore west and south coast benthic biogeographic ecotypes of South Africa. The application of new tools to quantify the functional diversity of epifauna as indicators of ecosystem health, and their potential physical drivers. This provided a platform on which to advance our understanding of benthic communities and the roles they play in ecosystem functioning under changing environments. Functional trait-based approaches such as those applied in this study can provide us with vital information on the relationship between biodiversity, ecosystem functioning, and physical drivers. Environmental stressors and changing climate patterns threaten to impact marine ecosystems and their functioning. Benthic epifauna are especially sensitive to changes in their environment and these fluctuations could potentially lead to the loss of certain benthic functionality, altering the thresholds these ecosystems have to response to disturbances. This undermines the stability of these ecosystems which can have ripple effects on the health of these ecosystems and their ability to provide the ecosystem services humans dependent on. Having suitable tools to track current and predict future changes will therefore be vital to inform management and conservation strategies for sustainable ocean utilisation. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Van Stavel, Jordan , Morris, Tamaryn
- Date: 2023-12
- Subjects: Marine ecology , Marine biology -- South Africa , Oceanography -- South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62698 , vital:72931
- Description: Offshore benthic ecosystems (> 200 m depth) are challenging to access and remain poorly studied globally. Epifaunal invertebrates comprise a critical trophic level in benthic ecosystems and can serve as indicators of the overall health and functioning. There is limited knowledge of South Africa’s offshore marine environment and benthic ecosystem functioning due to limitations in funding, resources, and the lack of suitable science-based monitoring tools which are vital for sustainable management into the future. The aim of this research was to improve the understanding of epifaunal functioning as well as their potential physical drivers in 13 South African offshore biogeographic ecotypes. The objectives of this study were threefold: 1) to investigate the functional composition of benthic epifauna from 13 biogeographic ecotypes, 2) to quantify the Functional Diversity (FD) associated with epifaunal traits between the different assemblages (i.e. biogeographic ecotypes), and 3) to evaluate the relationship between physical variables and epifaunal functional traits at the biogeographic ecotype level. Biological trait-based approaches were applied to a subset of 80 benthic epifaunal species collected from 909 offshore stations along the west and south coasts of South Africa. Nine biological traits (associated with life history, morphology and behavioural characteristics exhibited by each species) were classified into 39 modalities and weighted with biomass. Community Weighted Means (CWMs) were used to evaluate the benthic epifaunal functional trait composition of the 13 biogeographic ecotypes. Functional composition across the 13 ecotype assemblages on the west and south coast appeared to be dominated by species with similar trait compositions, such as large, long-lived, surface crawling/burrowing/filter-feeding epifauna with medium to no mobility, however, their percentage of contribution to trait expression (CWMs) was higher on the west coast. Functional diversity indices (alpha and beta) showed higher overall FD for west coast ecotypes, with most ecotypes on the continental shelf (except slopes and canyons) being significantly different (p<0.05) from ecotypes on the south coast. The global RLQ (three-table co-inertia) test did not reveal a significant relationship between biomass and physical variables or between biomass and traits (p>0.05). The fourth-corner method was used to test the significance of individual traitenvironment relationships. The fourth-corner results were similar overall to the RLQ analysis, revealing that three physical variables (temperature, depth, and fluorescence) were significantly correlated to two trait modalities belonging to the feeding mode filter-feeders (FM1) and scavengers (FM5). Scavengers were positively correlated with depth and negatively with temperature, while filter-feeders were positively correlated with fluorescence levels. This indicated that the presence of scavenging epifauna increased with a decrease in temperature and an increase in depth. While a positive significant correlation between filter-feeders and fluorescence suggested their potential tolerance or preference for environmental conditions with high levels of fluorescence. This research was the first such study to explore the functional composition and diversity of benthic epifauna and their relationship with potential physical drivers in offshore west and south coast benthic biogeographic ecotypes of South Africa. The application of new tools to quantify the functional diversity of epifauna as indicators of ecosystem health, and their potential physical drivers. This provided a platform on which to advance our understanding of benthic communities and the roles they play in ecosystem functioning under changing environments. Functional trait-based approaches such as those applied in this study can provide us with vital information on the relationship between biodiversity, ecosystem functioning, and physical drivers. Environmental stressors and changing climate patterns threaten to impact marine ecosystems and their functioning. Benthic epifauna are especially sensitive to changes in their environment and these fluctuations could potentially lead to the loss of certain benthic functionality, altering the thresholds these ecosystems have to response to disturbances. This undermines the stability of these ecosystems which can have ripple effects on the health of these ecosystems and their ability to provide the ecosystem services humans dependent on. Having suitable tools to track current and predict future changes will therefore be vital to inform management and conservation strategies for sustainable ocean utilisation. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Honouring the Dead: The Psychological Consequences of the COVID-19 Lockdown Restrictions on Burial Practices and Rituals, amongst AmaXhosa from the Eastern Cape, South Africa
- Authors: Sibam-Twalo, Zimkhitha
- Date: 2023-12
- Subjects: Death and burial , COVID-19 Lockdown
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63005 , vital:73081
- Description: Honouring the dead is upheld in religions and cultures across the world and embedded in rituals and rites of passage that must be adhered to. In many instances, religio-cultural beliefs synthesise or overlap, creating a mutual influence on the person. These religio-cultural rituals are symbolic and important for the living, but they are also equally important for the dead in order to ensure that their souls are returned to the source of their belief system. The COVID-19 lockdown restrictions in South Africa altered death ceremonies and rituals by limiting social gatherings to 50 people to ensure safety protocols like mask wearing and physical distancing. Additionally, family members were prohibited from interacting with the deceased’s body, including performing rituals like washing and dressing, to prevent virus spread. The resultant psychological consequences of these changes to burial practices have not been fully explored in the South African context, and given the importance rituals play, it becomes important to understand them. Studying the psychological consequences of the changes provided insights into individuals’ grief and loss coping in the absence of traditional burial rituals and practices. This is aimed at assisting with the development of interventions for mental health and well-being in future crises. The study explored the psychological consequences of COVID-19 lockdown restrictions on AmaXhosa burial practices and rituals in the Eastern Cape Province of South Africa. AmaXhosa have a rich cultural heritage that places great significance on death and burial rituals. These rituals serve as a way to honour and remember the deceased, provide closure for the bereaved, and maintain social cohesion within the community. The absence of these rituals during the COVID-19 lockdown had consequences for the AmaXhosa’s psychological and religio-cultural well-being. The exploration of their experiences was thus important because it shed light on the importance of these rituals and will help devise innovative ways to address their psychological needs during times of loss. The study utilised a qualitative method, conducting interviews with AmaXhosa aged 18 and older. Participants , Thesis (PhD) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Sibam-Twalo, Zimkhitha
- Date: 2023-12
- Subjects: Death and burial , COVID-19 Lockdown
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63005 , vital:73081
- Description: Honouring the dead is upheld in religions and cultures across the world and embedded in rituals and rites of passage that must be adhered to. In many instances, religio-cultural beliefs synthesise or overlap, creating a mutual influence on the person. These religio-cultural rituals are symbolic and important for the living, but they are also equally important for the dead in order to ensure that their souls are returned to the source of their belief system. The COVID-19 lockdown restrictions in South Africa altered death ceremonies and rituals by limiting social gatherings to 50 people to ensure safety protocols like mask wearing and physical distancing. Additionally, family members were prohibited from interacting with the deceased’s body, including performing rituals like washing and dressing, to prevent virus spread. The resultant psychological consequences of these changes to burial practices have not been fully explored in the South African context, and given the importance rituals play, it becomes important to understand them. Studying the psychological consequences of the changes provided insights into individuals’ grief and loss coping in the absence of traditional burial rituals and practices. This is aimed at assisting with the development of interventions for mental health and well-being in future crises. The study explored the psychological consequences of COVID-19 lockdown restrictions on AmaXhosa burial practices and rituals in the Eastern Cape Province of South Africa. AmaXhosa have a rich cultural heritage that places great significance on death and burial rituals. These rituals serve as a way to honour and remember the deceased, provide closure for the bereaved, and maintain social cohesion within the community. The absence of these rituals during the COVID-19 lockdown had consequences for the AmaXhosa’s psychological and religio-cultural well-being. The exploration of their experiences was thus important because it shed light on the importance of these rituals and will help devise innovative ways to address their psychological needs during times of loss. The study utilised a qualitative method, conducting interviews with AmaXhosa aged 18 and older. Participants , Thesis (PhD) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12
Insights into the relative abundance, demographics and behaviour of sea turtles along the east coast of South Africa
- Authors: dos Santos, Natalie Aida
- Date: 2023-12
- Subjects: Sea turtles -- Conservation -- South Africa , Sea turtles -- South Africa , Photogrammetry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62495 , vital:72778
- Description: Sea turtles are ecologically important species that have endured a history of overexploitation. Combined with their long, complex life cycles and ongoing anthropogenic pressures, they remain conservation-dependent. Conservation efforts worldwide focus on sea turtle nesting beach protection, however, comprehensive management strategies require an understanding of their lives at sea which are often spent in distant waters. This understanding is hindered by the relative challenges of in-water studies. South Africa has also focused research and conservation efforts on nesting adult female loggerheads (Caretta caretta) and leatherbacks (Dermochelys coriacea), largely overlooking the species or age classes remaining at sea. Green turtles (Chelonia mydas), hawksbills (Eretmochelys imbricata) and non-breeding loggerheads are frequently stranded and rehabilitated by aquaria, and observed by recreational divers on reefs, suggesting year-round residency along the country’s entire seaboard. Recent technological advancements in photo-identification methods for sea turtles, underwater photography and internet connectivity allowing even recreational divers to become citizen scientists now place us on the verge of an exciting opportunity to unravel the cryptic in-water ecology of these species. The overall aim of this study was to conduct the first assessment of relative abundance, demographics, distribution, and behaviour of sea turtles on reefs within the iSimangaliso and Aliwal Shoal Marine Protected Areas (MPAs) on the east coast of South Africa. A robust photo-identification database was established from research dives, voluntourism and citizen science contributions over a two-year period. From 1057 sightings in the two MPAs, a total of 227 individual sea turtles were identified constituting three species (green turtles: n = 120; hawksbills: n = 46; loggerheads: n = 61). Their relative abundance was proportional to the overall sizes of the South West Indian Ocean (SWIO) populations (green turtles > hawksbills > loggerheads > leatherbacks). However, sightings per unit effort (SPUE) showed that loggerheads were more prevalent than hawksbills in iSimangaliso, likely due to its proximity to this loggerhead rookery. Reefs supported mixed size aggregations with juvenile to adult-sized green turtles (straight carapace lengths, SCLs of 44.9–99.2 cm), whilst hawksbills were mostly juveniles or subadults (SCL range: 37.4–73.4 cm) and loggerheads were mostly adult-sized (SCL range: 66.9–81 cm). Adult sex ratios were slightly female-biased but not significantly different from 1:1. The longest minimum residence periods recorded for individual subadult green and hawksbill turtles (676 and 675 days respectively) and adult-sized loggerheads (621 days) were suggestive of residency. Resident sea turtle activities were typical; they wereobserved foraging, resting, cleaning and interacting year-round, whilst only loggerheads and leatherbacks were observed in breeding behaviour (e.g., patrolling and mating) just after the seasonal arrival of transient individuals. This study thus reveals that the east coast of South Africa hosts regionally important resident and transient sea turtle aggregations with some of the highest SPUE results recorded for the region. This first attempt at monitoring foraging grounds using a variety of techniques and stakeholder groups can serve as the baseline assessment for future work and the foundation for a long-term in-water monitoring programme, allowing for expansion along the entire coastline. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: dos Santos, Natalie Aida
- Date: 2023-12
- Subjects: Sea turtles -- Conservation -- South Africa , Sea turtles -- South Africa , Photogrammetry
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62495 , vital:72778
- Description: Sea turtles are ecologically important species that have endured a history of overexploitation. Combined with their long, complex life cycles and ongoing anthropogenic pressures, they remain conservation-dependent. Conservation efforts worldwide focus on sea turtle nesting beach protection, however, comprehensive management strategies require an understanding of their lives at sea which are often spent in distant waters. This understanding is hindered by the relative challenges of in-water studies. South Africa has also focused research and conservation efforts on nesting adult female loggerheads (Caretta caretta) and leatherbacks (Dermochelys coriacea), largely overlooking the species or age classes remaining at sea. Green turtles (Chelonia mydas), hawksbills (Eretmochelys imbricata) and non-breeding loggerheads are frequently stranded and rehabilitated by aquaria, and observed by recreational divers on reefs, suggesting year-round residency along the country’s entire seaboard. Recent technological advancements in photo-identification methods for sea turtles, underwater photography and internet connectivity allowing even recreational divers to become citizen scientists now place us on the verge of an exciting opportunity to unravel the cryptic in-water ecology of these species. The overall aim of this study was to conduct the first assessment of relative abundance, demographics, distribution, and behaviour of sea turtles on reefs within the iSimangaliso and Aliwal Shoal Marine Protected Areas (MPAs) on the east coast of South Africa. A robust photo-identification database was established from research dives, voluntourism and citizen science contributions over a two-year period. From 1057 sightings in the two MPAs, a total of 227 individual sea turtles were identified constituting three species (green turtles: n = 120; hawksbills: n = 46; loggerheads: n = 61). Their relative abundance was proportional to the overall sizes of the South West Indian Ocean (SWIO) populations (green turtles > hawksbills > loggerheads > leatherbacks). However, sightings per unit effort (SPUE) showed that loggerheads were more prevalent than hawksbills in iSimangaliso, likely due to its proximity to this loggerhead rookery. Reefs supported mixed size aggregations with juvenile to adult-sized green turtles (straight carapace lengths, SCLs of 44.9–99.2 cm), whilst hawksbills were mostly juveniles or subadults (SCL range: 37.4–73.4 cm) and loggerheads were mostly adult-sized (SCL range: 66.9–81 cm). Adult sex ratios were slightly female-biased but not significantly different from 1:1. The longest minimum residence periods recorded for individual subadult green and hawksbill turtles (676 and 675 days respectively) and adult-sized loggerheads (621 days) were suggestive of residency. Resident sea turtle activities were typical; they wereobserved foraging, resting, cleaning and interacting year-round, whilst only loggerheads and leatherbacks were observed in breeding behaviour (e.g., patrolling and mating) just after the seasonal arrival of transient individuals. This study thus reveals that the east coast of South Africa hosts regionally important resident and transient sea turtle aggregations with some of the highest SPUE results recorded for the region. This first attempt at monitoring foraging grounds using a variety of techniques and stakeholder groups can serve as the baseline assessment for future work and the foundation for a long-term in-water monitoring programme, allowing for expansion along the entire coastline. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Integrating state-space modelling and systematic conservation planning to recommend penguin-fishery management zones in Algoa Bay, South Africa
- Stockdale, Victoria, Goodall, Victoria, Clifford-Holmes, Jia
- Authors: Stockdale, Victoria , Goodall, Victoria , Clifford-Holmes, Jia
- Date: 2023-12
- Subjects: Biodiversity conservation -- South Africa -- Port Elizabeth , Natural resource conservation , Marine ecology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62611 , vital:72828
- Description: Direct anthropogenic impacts on vulnerable marine ecosystems are growing and require effective conservation measures. Integrating the cost impacts of conservation interventions and optimising the spatiotemporal scale of management interventions may improve cohesion between opposing marine users. This study aimed to integrate spatial and temporal models to advise dynamic penguin-fishery management plans in Algoa Bay, off Gqeberha, South Africa, that would maximise penguin foraging success while minimising the impact on the fishing industry. Determining the foraging locations important to breeding penguins is fundamental when understanding the relationship between fisheries and prey availability. Using Global Positioning System (GPS) data gathered from feeding trips of breeding African penguins between 2012 and 2017, and a hidden Markov model, three behavioural states (foraging, commuting, transitioning) were inferred and used as conservation targets in spatial prioritisation using the prioritizr package in R. The cost to the fishery was estimated using the catch of pelagic fish by the fishing industry between 2012 and 2015 as the proxy. The energetic cost to penguins was the distance they travelled from their breeding colony. Nine prioritisation scenarios, varying in levels of conservation for penguins, spatial cohesion and costs to fisheries, were developed using all year’s combined data to explore an ‘optimal’ closure configuration. The optimal closure was determined as an area which met the targets for penguin conservation, with a low cost to the fishery, close to the breeding colony and spatially clumped. The best solution from each scenario was isolated and the solution for the conservation target of 20% foraging habitat, 10% commuting habitat and 10% transitioning habitat and a boundary penalty of 0.01 (a dimensionless value that is used to reduce spatial fragmentation – increasing the value of the parameter signals that it is important to minimise the total exposed boundary of the prioritisation by favouring solutions where units are clumped together) was chosen as the optimal closure. This configuration was used as a static closure and applied to individual fishing seasons to estimate how the cost of a static closure design to the fishery would vary between seasons. Subsequently, a dynamic closure was designed using the same optimal configuration criteria every year, and the cost to the fishing industry was compared seasonally with the cost of a static closure. The cost to fisheries of dynamic closures was consistently lower than that of a static closure and the area required to meet the penguin feeding targets was drastically reduced. While dynamic closure scenarios show promise to minimise costs to the industry while meeting penguin conservation targets, these configurations were designed retrospectively with data collected after the end of the fishery seasons. For efficient management, the closures need to be designed by using data collected at an appropriate temporal scale. For that, the critical missing dimension to this study is the addition of real-time data on pelagic fish positions, areas of fishing intensity and sites of penguin foraging to create appropriate recommendations for up-to-date fishery exclusion zones. Therefore, the priority now is to explore methods of collecting real-time data on pelagic fish abundance, feeding behaviour of penguins at sea, site and mass of pelagic fishery catch, and using these data to delineate real-time, dynamic closures, coupled with a governance and management strategy that can implement dynamic closures. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Stockdale, Victoria , Goodall, Victoria , Clifford-Holmes, Jia
- Date: 2023-12
- Subjects: Biodiversity conservation -- South Africa -- Port Elizabeth , Natural resource conservation , Marine ecology
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62611 , vital:72828
- Description: Direct anthropogenic impacts on vulnerable marine ecosystems are growing and require effective conservation measures. Integrating the cost impacts of conservation interventions and optimising the spatiotemporal scale of management interventions may improve cohesion between opposing marine users. This study aimed to integrate spatial and temporal models to advise dynamic penguin-fishery management plans in Algoa Bay, off Gqeberha, South Africa, that would maximise penguin foraging success while minimising the impact on the fishing industry. Determining the foraging locations important to breeding penguins is fundamental when understanding the relationship between fisheries and prey availability. Using Global Positioning System (GPS) data gathered from feeding trips of breeding African penguins between 2012 and 2017, and a hidden Markov model, three behavioural states (foraging, commuting, transitioning) were inferred and used as conservation targets in spatial prioritisation using the prioritizr package in R. The cost to the fishery was estimated using the catch of pelagic fish by the fishing industry between 2012 and 2015 as the proxy. The energetic cost to penguins was the distance they travelled from their breeding colony. Nine prioritisation scenarios, varying in levels of conservation for penguins, spatial cohesion and costs to fisheries, were developed using all year’s combined data to explore an ‘optimal’ closure configuration. The optimal closure was determined as an area which met the targets for penguin conservation, with a low cost to the fishery, close to the breeding colony and spatially clumped. The best solution from each scenario was isolated and the solution for the conservation target of 20% foraging habitat, 10% commuting habitat and 10% transitioning habitat and a boundary penalty of 0.01 (a dimensionless value that is used to reduce spatial fragmentation – increasing the value of the parameter signals that it is important to minimise the total exposed boundary of the prioritisation by favouring solutions where units are clumped together) was chosen as the optimal closure. This configuration was used as a static closure and applied to individual fishing seasons to estimate how the cost of a static closure design to the fishery would vary between seasons. Subsequently, a dynamic closure was designed using the same optimal configuration criteria every year, and the cost to the fishing industry was compared seasonally with the cost of a static closure. The cost to fisheries of dynamic closures was consistently lower than that of a static closure and the area required to meet the penguin feeding targets was drastically reduced. While dynamic closure scenarios show promise to minimise costs to the industry while meeting penguin conservation targets, these configurations were designed retrospectively with data collected after the end of the fishery seasons. For efficient management, the closures need to be designed by using data collected at an appropriate temporal scale. For that, the critical missing dimension to this study is the addition of real-time data on pelagic fish positions, areas of fishing intensity and sites of penguin foraging to create appropriate recommendations for up-to-date fishery exclusion zones. Therefore, the priority now is to explore methods of collecting real-time data on pelagic fish abundance, feeding behaviour of penguins at sea, site and mass of pelagic fishery catch, and using these data to delineate real-time, dynamic closures, coupled with a governance and management strategy that can implement dynamic closures. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Investigating the effect of peptide-functionalized gold nanoparticles on colon cancer cells
- Authors: Ramagoma, Rolivhuwa Bishop
- Date: 2023-12
- Subjects: Colon (Anatomy) -- Cancer -- Research , Colon (Anatomy) -- Cancer -- Treatment , Nanoparticles
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62564 , vital:72824
- Description: Colon cancer like any other cancer is a condition in which cells grow uncontrollably and may even spread to other regions of the body through metastasis. Colon cancer was ranked the second leading cause of cancer related deaths worldwide in 2018. Research to advance treatment of cancer keeps advancing daily, However, a big challenge is drug-induced side effects due to toxicity against normal body cells. Therefore, the development of controlled release technologies in conjunction with targeted drug delivery may provide a more efficient and less dangerous approach to overcome the limits of traditional chemotherapy. Including the creation of nanoscale delivery vehicles capable of directing the release of chemotherapeutic drugs into cancer cells only. This study aims to investigate p14 peptide that would specifically target colorectal cancer cells and not normal body cells to develop a targeted drug delivery system using gold nanoparticles. This study serves as a pilot study of the primary aim. To achieve this, the effect of the peptide p14 and peptide functionalized gold nanoparticles (p14-AuNP) on colon cancer cells (HT-29) and normal epithelial cells (KMST-6) was determined. Firstly, gold nanoparticles were chemically synthesised and then functionalized with p14 peptide through Polyethylene glycol. Then assessment of their effect through in vitro cytotoxicity assay (MTT) and gene expression analysis (RT-qPCR) was conducted. Nanoparticles’ synthesis and functionalization was performed and confirmed: In vitro cytotoxicity through MTT assay was successfully conducted and p14-AuNP showed toxicity against colon cancer cells and lesser toxicity towards normal cells as compared to 5-Flourouracil (commercially approved drug for colon cancer treatment). Gene expression analysis revealed that apoptosis was induced in both cell lines by p14-AuNP either through upregulation of caspase 3, 7 and/or BCL2. A cell survival gene, AKT1, also had significant effect on this. CDC42 was downregulated which indicates that cell proliferation was inhibited. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Ramagoma, Rolivhuwa Bishop
- Date: 2023-12
- Subjects: Colon (Anatomy) -- Cancer -- Research , Colon (Anatomy) -- Cancer -- Treatment , Nanoparticles
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62564 , vital:72824
- Description: Colon cancer like any other cancer is a condition in which cells grow uncontrollably and may even spread to other regions of the body through metastasis. Colon cancer was ranked the second leading cause of cancer related deaths worldwide in 2018. Research to advance treatment of cancer keeps advancing daily, However, a big challenge is drug-induced side effects due to toxicity against normal body cells. Therefore, the development of controlled release technologies in conjunction with targeted drug delivery may provide a more efficient and less dangerous approach to overcome the limits of traditional chemotherapy. Including the creation of nanoscale delivery vehicles capable of directing the release of chemotherapeutic drugs into cancer cells only. This study aims to investigate p14 peptide that would specifically target colorectal cancer cells and not normal body cells to develop a targeted drug delivery system using gold nanoparticles. This study serves as a pilot study of the primary aim. To achieve this, the effect of the peptide p14 and peptide functionalized gold nanoparticles (p14-AuNP) on colon cancer cells (HT-29) and normal epithelial cells (KMST-6) was determined. Firstly, gold nanoparticles were chemically synthesised and then functionalized with p14 peptide through Polyethylene glycol. Then assessment of their effect through in vitro cytotoxicity assay (MTT) and gene expression analysis (RT-qPCR) was conducted. Nanoparticles’ synthesis and functionalization was performed and confirmed: In vitro cytotoxicity through MTT assay was successfully conducted and p14-AuNP showed toxicity against colon cancer cells and lesser toxicity towards normal cells as compared to 5-Flourouracil (commercially approved drug for colon cancer treatment). Gene expression analysis revealed that apoptosis was induced in both cell lines by p14-AuNP either through upregulation of caspase 3, 7 and/or BCL2. A cell survival gene, AKT1, also had significant effect on this. CDC42 was downregulated which indicates that cell proliferation was inhibited. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Investigating the interannual variability of the Benguela coastal upwelling system using a ROMS numerical model from 1993-2014
- Silima, Rudzani Faith, Roagosha, Moagabo
- Authors: Silima, Rudzani Faith , Roagosha, Moagabo
- Date: 2023-12
- Subjects: Oceanography , Coasts , Marine sciences
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62586 , vital:72826
- Description: The seasonal and interannual variability of the coastal Benguela upwelling system is described using 22 years (September 1993 - December 2014) of a regional Ocean model (ROMS) output. The model-derived SSTs are evaluated against satellite SSTs (GHRSST) and biases between the datasets investigated, allowing for confidence in using the ROMS data to investigate details of spatial and temporal variability over the Benguela System. Variability of coastal SSTs are investigated together with alongshore winds (from the ERA-Interim Reanalysis product). The driver of the seasonality in upwelling in the Benguela region is the seasonal shift of the South Atlantic High pressure system, leading to an enhanced seasonal signal in the southern Benguela (with strongest upwelling favourable winds in austral spring and summer). In the northern Benguela, the seasonal signal reduces with the peak of upwelling favourable winds shifting to late winter and spring. Interannual variability is evident in the model and is investigated with respect to various modes of climate variability. Though the direct relationship of the Benguela upwelling system to large-scale climate modes such as SAM and ENSO is not clear in most places, some evidence was found for their connection. For instance, in the southernmost cell of the southern Benguela a significant positive and negative correlation exists between SST and wind respectively with ENSO during summer months. This relates to increased (decreased) winds and decreased (increased) SST during La Niña (El Niño) events. Although there was no direct correlation with either SST or alongshore wind anywhere in the Benguela system, there was some indication of its importance. A trend toward a positive SAM (i.e a more poleward position of the South Atlantic High-Pressure system) was consistent with a trend toward enhanced winds and reduced SSTs in the southernmost upwelling cell. In addition to this, there was evidence to suggest that when SAM and ENSO are out-of-phase, which occurred primarily during summer months, the wind and SST response is amplified. This seemed to be particularly true in the first 10 years of the timeseries when the anomalies were strongly alternating. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Silima, Rudzani Faith , Roagosha, Moagabo
- Date: 2023-12
- Subjects: Oceanography , Coasts , Marine sciences
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62586 , vital:72826
- Description: The seasonal and interannual variability of the coastal Benguela upwelling system is described using 22 years (September 1993 - December 2014) of a regional Ocean model (ROMS) output. The model-derived SSTs are evaluated against satellite SSTs (GHRSST) and biases between the datasets investigated, allowing for confidence in using the ROMS data to investigate details of spatial and temporal variability over the Benguela System. Variability of coastal SSTs are investigated together with alongshore winds (from the ERA-Interim Reanalysis product). The driver of the seasonality in upwelling in the Benguela region is the seasonal shift of the South Atlantic High pressure system, leading to an enhanced seasonal signal in the southern Benguela (with strongest upwelling favourable winds in austral spring and summer). In the northern Benguela, the seasonal signal reduces with the peak of upwelling favourable winds shifting to late winter and spring. Interannual variability is evident in the model and is investigated with respect to various modes of climate variability. Though the direct relationship of the Benguela upwelling system to large-scale climate modes such as SAM and ENSO is not clear in most places, some evidence was found for their connection. For instance, in the southernmost cell of the southern Benguela a significant positive and negative correlation exists between SST and wind respectively with ENSO during summer months. This relates to increased (decreased) winds and decreased (increased) SST during La Niña (El Niño) events. Although there was no direct correlation with either SST or alongshore wind anywhere in the Benguela system, there was some indication of its importance. A trend toward a positive SAM (i.e a more poleward position of the South Atlantic High-Pressure system) was consistent with a trend toward enhanced winds and reduced SSTs in the southernmost upwelling cell. In addition to this, there was evidence to suggest that when SAM and ENSO are out-of-phase, which occurred primarily during summer months, the wind and SST response is amplified. This seemed to be particularly true in the first 10 years of the timeseries when the anomalies were strongly alternating. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Isadora duncan: An instrumental case study
- Authors: Volker,Lauren
- Date: 2023-12
- Subjects: Analytical Psychology , Psychology of women
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63038 , vital:73084
- Description: The study is an instrumental case study of Isadora Duncan (1877 - 1927). She was a pioneer of modern dance as she developed her unique style of dance that was free-flowing and natural. She further developed her own dance philosophy, which drew the attention of many as its archetypal dancer was a woman who embodied a space that was equal and free. She was not only revolutionary in her unique dance style but also for her strong beliefs. Isadora Duncan believed in anti-marriage, bearing children out of wedlock, and fighting for the emancipation of women where she used dance, her philosophy and post-performance lectures to communicate her thoughts and beliefs. An Instrumental case study is a qualitative method of enquiry, which entails researching an event or individual as a means of providing or gaining insight into a particular phenomenon. Similar to that of a psychobiography, the individual subject can be explored through the lens of a psychological theory for the purpose of creating a coherent psychological case study. The psychoanalytical lens of Carl Jung was used to explore and describe certain aspects of the life and work of Isadora Duncan. The subfield of the Psychology of Women provides a contextual description for the challenges that women faced in the past and in the present, and additionally presents the primary aim of the proposed study. Isadora Duncan was chosen due to her unique dance movement, both literally and figuratively as she developed her ability in giving voice to those emotions that women often kept hidden. She lived during significant times which included radical transformations that brought about noticeable change politically, socially, and culturally. Despite the reformative motions, it did not dismiss its own challenges especially for women. Women faced a constant struggle for freedom from oppression, community rights and gender equality, and Isadora Duncan was no exception to these challenges. Extensive biographical information data was collected and processed into salient features. The study integrates the theory of Carl Jung, the life and dance philosophy of Isadora Duncan and the v challenges faced by women over the centuries and demonstrates the value of using an instrumental case study as a method of inquiry into the exploration of a unique individual. The Psychology of Women provides an understanding of how those past challenges may still be modern-day concerns for the psychology of women today. The findings of the study demonstrated that Isadora Duncan was a unique and innovate women who pushed the boundaries socially. She was determined to perform her unique dance style in times that required women to conform to the cultural expectations. However, in times of trouble and despair, she was able to turn to dance as the individual and collective voice. The contribution of the study rests with its demonstration of the value of a holistic and reflexive exploration of a unique individual woman. It demonstrates the value and application of Jung’s in-depth theoretical understanding of the archetypes in human behaviour and the use of dance as a healing process for psychologically wounded women. Therefore, specific reference to the true inner voice of women allows insight into how clinicians might assist female clients who struggle to release their true inner voice. Furthermore, the study contributes to building knowledge of the challenges that women face in society and allows for future research of exploring integrative theoretical frameworks in understanding the healing of psychologically fragmented women in the 21st century. , Thesis (Ma) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Volker,Lauren
- Date: 2023-12
- Subjects: Analytical Psychology , Psychology of women
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/63038 , vital:73084
- Description: The study is an instrumental case study of Isadora Duncan (1877 - 1927). She was a pioneer of modern dance as she developed her unique style of dance that was free-flowing and natural. She further developed her own dance philosophy, which drew the attention of many as its archetypal dancer was a woman who embodied a space that was equal and free. She was not only revolutionary in her unique dance style but also for her strong beliefs. Isadora Duncan believed in anti-marriage, bearing children out of wedlock, and fighting for the emancipation of women where she used dance, her philosophy and post-performance lectures to communicate her thoughts and beliefs. An Instrumental case study is a qualitative method of enquiry, which entails researching an event or individual as a means of providing or gaining insight into a particular phenomenon. Similar to that of a psychobiography, the individual subject can be explored through the lens of a psychological theory for the purpose of creating a coherent psychological case study. The psychoanalytical lens of Carl Jung was used to explore and describe certain aspects of the life and work of Isadora Duncan. The subfield of the Psychology of Women provides a contextual description for the challenges that women faced in the past and in the present, and additionally presents the primary aim of the proposed study. Isadora Duncan was chosen due to her unique dance movement, both literally and figuratively as she developed her ability in giving voice to those emotions that women often kept hidden. She lived during significant times which included radical transformations that brought about noticeable change politically, socially, and culturally. Despite the reformative motions, it did not dismiss its own challenges especially for women. Women faced a constant struggle for freedom from oppression, community rights and gender equality, and Isadora Duncan was no exception to these challenges. Extensive biographical information data was collected and processed into salient features. The study integrates the theory of Carl Jung, the life and dance philosophy of Isadora Duncan and the v challenges faced by women over the centuries and demonstrates the value of using an instrumental case study as a method of inquiry into the exploration of a unique individual. The Psychology of Women provides an understanding of how those past challenges may still be modern-day concerns for the psychology of women today. The findings of the study demonstrated that Isadora Duncan was a unique and innovate women who pushed the boundaries socially. She was determined to perform her unique dance style in times that required women to conform to the cultural expectations. However, in times of trouble and despair, she was able to turn to dance as the individual and collective voice. The contribution of the study rests with its demonstration of the value of a holistic and reflexive exploration of a unique individual woman. It demonstrates the value and application of Jung’s in-depth theoretical understanding of the archetypes in human behaviour and the use of dance as a healing process for psychologically wounded women. Therefore, specific reference to the true inner voice of women allows insight into how clinicians might assist female clients who struggle to release their true inner voice. Furthermore, the study contributes to building knowledge of the challenges that women face in society and allows for future research of exploring integrative theoretical frameworks in understanding the healing of psychologically fragmented women in the 21st century. , Thesis (Ma) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12
Knowledge, attitudes and practices of municipal workers regarding occupational health and safety in the garden route district municipality, Western Cape
- Authors: Shoto, Khanyisa
- Date: 2023-12
- Subjects: Occupational health and safety , Personal protective equipment
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62991 , vital:73080
- Description: Background: Workers accidents at work have been demonstrated to be increasingly common and expensive, particularly in developing nations like South Africa. The failure of employers and employees to support and comply to (OHS) regulations measures frequently leads to injuries and accidents that are extremely expensive for both the employer and employees. Regardless of South African legislations that aim to prevent accidents and injuries, scourging statistics of industrial accidents are still a characteristic of OHS. Objectives: This study investigates knowledge gaps, attitude, and the practice of municipal workers regarding OHS at Garden Route District Municipality (GRDM) in the Western Cape Province of South Africa. Methodology: Quantitative approach was taken, and questionnaires were administered to 188 workers employed by the GRDM. A probability sampling method of stratified sampling method was utilised. Results: This study concluded that the workers of the GRDM are knowledgeable about OHS in their workplaces and that municipal workers positively perceive OHS issues in their workplaces. The main reason for this positive perception is because of the management support that the workers receive from the GRDM with regards to OHS matters. Furthermore most workers positively perceived OHS protocols and measures undertaken at the GRDM. Statistical tests proved that the municipal workers who positively perceived OHS protocols and measures were significantly higher (p< 0.05) than those that negatively perceived OHS protocols. Conclusion: The study revealed that GRDM workers were knowledgeable on OHS protocols. This was because of the support that they get from their employer as well as personal health and safety concerns. They positively perceived the OSH measures that are put in place to prevent accidents and injuries. It is only an insignificant percentage of individuals that disagreed with some of the OHS measures and protocols. This study contributes immeasurably to academic research in the field of OHS and extends knowledge that relates workers’ perceptions, safety awareness, as well as workers’ adherence to safety and behaviour. , Thesis (Ma) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Shoto, Khanyisa
- Date: 2023-12
- Subjects: Occupational health and safety , Personal protective equipment
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62991 , vital:73080
- Description: Background: Workers accidents at work have been demonstrated to be increasingly common and expensive, particularly in developing nations like South Africa. The failure of employers and employees to support and comply to (OHS) regulations measures frequently leads to injuries and accidents that are extremely expensive for both the employer and employees. Regardless of South African legislations that aim to prevent accidents and injuries, scourging statistics of industrial accidents are still a characteristic of OHS. Objectives: This study investigates knowledge gaps, attitude, and the practice of municipal workers regarding OHS at Garden Route District Municipality (GRDM) in the Western Cape Province of South Africa. Methodology: Quantitative approach was taken, and questionnaires were administered to 188 workers employed by the GRDM. A probability sampling method of stratified sampling method was utilised. Results: This study concluded that the workers of the GRDM are knowledgeable about OHS in their workplaces and that municipal workers positively perceive OHS issues in their workplaces. The main reason for this positive perception is because of the management support that the workers receive from the GRDM with regards to OHS matters. Furthermore most workers positively perceived OHS protocols and measures undertaken at the GRDM. Statistical tests proved that the municipal workers who positively perceived OHS protocols and measures were significantly higher (p< 0.05) than those that negatively perceived OHS protocols. Conclusion: The study revealed that GRDM workers were knowledgeable on OHS protocols. This was because of the support that they get from their employer as well as personal health and safety concerns. They positively perceived the OSH measures that are put in place to prevent accidents and injuries. It is only an insignificant percentage of individuals that disagreed with some of the OHS measures and protocols. This study contributes immeasurably to academic research in the field of OHS and extends knowledge that relates workers’ perceptions, safety awareness, as well as workers’ adherence to safety and behaviour. , Thesis (Ma) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12
Knowledge, attitudes and practices regarding social media as a teaching strategy at a public nursing college in Limpopo province
- Authors: Halala, Pfukani Symantha
- Date: 2023-12
- Subjects: Nurse educators , Teaching strategy
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62849 , vital:73057
- Description: The emergence of social media (SM) in the academic arena has demonstrated the potential for innovation in teaching and learning. Moreover, its appeal is enhanced by its accessibility and affordability. Consequently, the use of SM has increased globally and has influenced interaction and socialisation amongst educators and learners. In addition, SM has affected learning and how educators teach and collaborate with learners when constructing knowledge in higher education settings. However, despite its advantages, nurse educators' use of SM is less than optimal in teaching. Therefore, the study aimed to explore nurse educators' knowledge, attitudes and practices regarding the use of SM as a teaching strategy at a public nursing college in the province of Limpopo, South Africa. The research design employed for this study was quantitative, explorative, descriptive and contextual, and Roger’s diffusion of innovation theory underpinned the study. Stratified, proportionate sampling was used to select the nurse educators who were respondents to the study’s survey via a questionnaire as the data collection instrument. An educator as a specialist in the use of SM, a statistician and the study supervisors reviewed the questionnaire. A pilot study was conducted to check the validity and reliability of the data collection instrument. Data gathered through the survey was statistically analysed to produce descriptive statistics. The researcher adhered to the ethical principles of respect, beneficence, and justice. The research results indicated that the nurse educators in the study were knowledgeable about SM platforms. Moreover, although they had a positive attitude towards incorporating SM as a teaching strategy. Therefore, based on the research results, recommendations were to facilitate the use of SM as a teaching strategy. , Thesis (Ma) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Halala, Pfukani Symantha
- Date: 2023-12
- Subjects: Nurse educators , Teaching strategy
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62849 , vital:73057
- Description: The emergence of social media (SM) in the academic arena has demonstrated the potential for innovation in teaching and learning. Moreover, its appeal is enhanced by its accessibility and affordability. Consequently, the use of SM has increased globally and has influenced interaction and socialisation amongst educators and learners. In addition, SM has affected learning and how educators teach and collaborate with learners when constructing knowledge in higher education settings. However, despite its advantages, nurse educators' use of SM is less than optimal in teaching. Therefore, the study aimed to explore nurse educators' knowledge, attitudes and practices regarding the use of SM as a teaching strategy at a public nursing college in the province of Limpopo, South Africa. The research design employed for this study was quantitative, explorative, descriptive and contextual, and Roger’s diffusion of innovation theory underpinned the study. Stratified, proportionate sampling was used to select the nurse educators who were respondents to the study’s survey via a questionnaire as the data collection instrument. An educator as a specialist in the use of SM, a statistician and the study supervisors reviewed the questionnaire. A pilot study was conducted to check the validity and reliability of the data collection instrument. Data gathered through the survey was statistically analysed to produce descriptive statistics. The researcher adhered to the ethical principles of respect, beneficence, and justice. The research results indicated that the nurse educators in the study were knowledgeable about SM platforms. Moreover, although they had a positive attitude towards incorporating SM as a teaching strategy. Therefore, based on the research results, recommendations were to facilitate the use of SM as a teaching strategy. , Thesis (Ma) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12
Marine benthic (epilithic) diatom communities along the coast of South Africa: A contribution to their diversity, spatio-temporal variations, and ecology
- Authors: Cotiyane-Pondo, Phumlile
- Date: 2023-12
- Subjects: Marine ecology , Marine biodiversity , Coastal ecology
- Language: English
- Type: Doctorate Dissertation , text
- Identifier: http://hdl.handle.net/10948/62453 , vital:72754
- Description: Diatoms remain one of the most diverse and ecologically important microorganisms within microphytobenthos. The highly variable South African coastline, comprised of heterogeneous rocky intertidal habitats provides the ideal study area to investigate epilithic microphytobenthos and their associated influential drivers. In South Africa, in-depth taxonomic research on marine littoral diatoms exists, however, quantitative research and knowledge on their abundance, diversity, community composition and distribution remain limited. Thus, the main aim of this research was to explore the spatial and temporal variability of marine benthic (epilithic) diatoms, in relation to the variable physico-chemical conditions in the nearshore intertidal environments along the coastline of South Africa. To achieve this, field-based observational (natural substrata) and experimental (artificial substrata) studies were conducted on selected locations around the coastline, with a large focus on south coast localities. For the Spatial studies, large (i.e., encompassing all three biogeographical regions) and small-scale (i.e., coastal island in the warm temperate region) surveys of epilithic diatom assemblages from natural rocky substrata were conducted. Large-scale investigation results revealed highly variable diatom assemblages, diversity and distribution, with compositional differences observed between the coastal sections (around the coastline). A total of 85 diatom taxa from 31 genera were observed at 15 sites, and the number of taxa varied un-systematically along coastline. Genera with noticeable contribution included Nitzschia, Cocconeis and Achnanthes. On the coastal Bird Island (small-scale), similar variability was observed, but with a much higher diatom diversity and number of rarely observed species (e.g. Actinoptychus senarius (Ehrenberg) Ehrenberg, Cocconeis capensis (Cholnoky) Witkowski, Fragilariopsis kerguelensis (O’Meara) Hustedt, Striatella unipunctata (Lyngbye) Agardh. Seventy-two (72) species from 35 genera were recorded with a varied abundance and diversity around the island. The study also revealed a high contribution of typical benthic diatom species to the surf zone environment around the island. To study temporal variations, medium-term compositional differences on natural substrata were assessed monthly over an annual cycle at a single site. A paucity of diatom material was evident during this study and observations indicated a trend of presence and absence of diatom taxa from the study site. Nineteen (19) diatom genera were identified and those observed, albeit as one or two individual valves, included taxa from several genera including Biddulphia, Diploneis, Campyloneis, Trachyneis and Triceratium. Noteworthy was a seasonal increase in the number of diatom valves encountered, with the highest diatom abundance observed during spring (September) and the genera Cocconeis, Grammatophora and Navicula appearing regularly. To complement the sparse data from the long-term temporal study, a short-term experimental study on artificial substrata (Plexiglass) revealed rapid temporal variations of benthic diatom assemblages. The composition differed spatio-temporally during the experimental period, with fluctuating species occurrences and abundances between the two study sites. The experimental study also revealed the highest number of diatom species observed during this research (134 species belonging to 44 genera). While Cocconeis (13 species) and Nitzschia (9 species) were the dominant genera, 48% of the diatomcomposition was composed of rarely observed taxa that included Cocconeis testudo Giffen, Donkinia sp., Paralia sulcata (Ehrenberg) Cleve. Regarding environmental drivers, the findings indicated the importance of temperature and nutrients in driving diatom spatial abundance and composition along the coastline, as well as the island. However, the potential influence of the interplay between measured variables and unexplored coastal oceanographic processes (e.g., wave action) was noted. Temporally, from the annual study, the nature of the rocky substrate (rock type) rather than environmental conditions was postulated to have been the influential factor that resulted in the low diatom abundance data, however this requires further in-depth investigations on the influence of rock microtopography on microphytobenthos in this region. Contrastingly, the experimental study results indicated environmental variables having varying influences on the diatom diversity indices, however, study site and sampling occasion were revealed as the most important predictors of the observed variability. Further, site-specific biofilm processes, including biological interaction (e.g. grazing), were shown to alter biofilm succession, thus influencing the observed diatom assemblages. Overall, this research provided new and relevant knowledge on the variability of benthic (epilithic) diatom composition, biodiversity and distribution along the coastline, further contributing to our understanding of marine benthic diatoms ecology, their ecological role in the context of intertidal food web and their potential as bioindicators of change in the coastal ecosystems in Southern Africa. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Cotiyane-Pondo, Phumlile
- Date: 2023-12
- Subjects: Marine ecology , Marine biodiversity , Coastal ecology
- Language: English
- Type: Doctorate Dissertation , text
- Identifier: http://hdl.handle.net/10948/62453 , vital:72754
- Description: Diatoms remain one of the most diverse and ecologically important microorganisms within microphytobenthos. The highly variable South African coastline, comprised of heterogeneous rocky intertidal habitats provides the ideal study area to investigate epilithic microphytobenthos and their associated influential drivers. In South Africa, in-depth taxonomic research on marine littoral diatoms exists, however, quantitative research and knowledge on their abundance, diversity, community composition and distribution remain limited. Thus, the main aim of this research was to explore the spatial and temporal variability of marine benthic (epilithic) diatoms, in relation to the variable physico-chemical conditions in the nearshore intertidal environments along the coastline of South Africa. To achieve this, field-based observational (natural substrata) and experimental (artificial substrata) studies were conducted on selected locations around the coastline, with a large focus on south coast localities. For the Spatial studies, large (i.e., encompassing all three biogeographical regions) and small-scale (i.e., coastal island in the warm temperate region) surveys of epilithic diatom assemblages from natural rocky substrata were conducted. Large-scale investigation results revealed highly variable diatom assemblages, diversity and distribution, with compositional differences observed between the coastal sections (around the coastline). A total of 85 diatom taxa from 31 genera were observed at 15 sites, and the number of taxa varied un-systematically along coastline. Genera with noticeable contribution included Nitzschia, Cocconeis and Achnanthes. On the coastal Bird Island (small-scale), similar variability was observed, but with a much higher diatom diversity and number of rarely observed species (e.g. Actinoptychus senarius (Ehrenberg) Ehrenberg, Cocconeis capensis (Cholnoky) Witkowski, Fragilariopsis kerguelensis (O’Meara) Hustedt, Striatella unipunctata (Lyngbye) Agardh. Seventy-two (72) species from 35 genera were recorded with a varied abundance and diversity around the island. The study also revealed a high contribution of typical benthic diatom species to the surf zone environment around the island. To study temporal variations, medium-term compositional differences on natural substrata were assessed monthly over an annual cycle at a single site. A paucity of diatom material was evident during this study and observations indicated a trend of presence and absence of diatom taxa from the study site. Nineteen (19) diatom genera were identified and those observed, albeit as one or two individual valves, included taxa from several genera including Biddulphia, Diploneis, Campyloneis, Trachyneis and Triceratium. Noteworthy was a seasonal increase in the number of diatom valves encountered, with the highest diatom abundance observed during spring (September) and the genera Cocconeis, Grammatophora and Navicula appearing regularly. To complement the sparse data from the long-term temporal study, a short-term experimental study on artificial substrata (Plexiglass) revealed rapid temporal variations of benthic diatom assemblages. The composition differed spatio-temporally during the experimental period, with fluctuating species occurrences and abundances between the two study sites. The experimental study also revealed the highest number of diatom species observed during this research (134 species belonging to 44 genera). While Cocconeis (13 species) and Nitzschia (9 species) were the dominant genera, 48% of the diatomcomposition was composed of rarely observed taxa that included Cocconeis testudo Giffen, Donkinia sp., Paralia sulcata (Ehrenberg) Cleve. Regarding environmental drivers, the findings indicated the importance of temperature and nutrients in driving diatom spatial abundance and composition along the coastline, as well as the island. However, the potential influence of the interplay between measured variables and unexplored coastal oceanographic processes (e.g., wave action) was noted. Temporally, from the annual study, the nature of the rocky substrate (rock type) rather than environmental conditions was postulated to have been the influential factor that resulted in the low diatom abundance data, however this requires further in-depth investigations on the influence of rock microtopography on microphytobenthos in this region. Contrastingly, the experimental study results indicated environmental variables having varying influences on the diatom diversity indices, however, study site and sampling occasion were revealed as the most important predictors of the observed variability. Further, site-specific biofilm processes, including biological interaction (e.g. grazing), were shown to alter biofilm succession, thus influencing the observed diatom assemblages. Overall, this research provided new and relevant knowledge on the variability of benthic (epilithic) diatom composition, biodiversity and distribution along the coastline, further contributing to our understanding of marine benthic diatoms ecology, their ecological role in the context of intertidal food web and their potential as bioindicators of change in the coastal ecosystems in Southern Africa. , Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Mechanical recyclability and biodegradation of biopolymers, biopolymer blends and biocomposite in natural environmental conditions
- Authors: Nomadolo, Nomvuyo Elizabeth
- Date: 2023-12
- Subjects: Polymers , Polymeric composites , Biopolymers
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62539 , vital:72822
- Description: The present research aimed at investigating mechanical recyclability and studying the potential biotic and abiotic degradation behaviors of biobased biodegradable polymers in different environmental conditions. The mechanical recyclability tests monitored the effect of multiple reprocessing on the mechanical, thermal, physical, chemical, and morphological properties of poly (butylene adipate-co-terephthalate) (PBAT), poly (butylene succinate) (PBS), poly (lactic acid) (PLA), PBAT-PBS blend, and PBAT-thermoplastic starch (TPS) composite. Low-density polyethylene (LDPE), a conventional non-biodegradable plastic, was also monitored for comparison studies. The mechanical recyclability tests were carried out by eight melt extrusion cycles using twin-screw extrusion and injection molding processing techniques. Tensile testing, impact analysis, melt flow index test (MFI), differential scanning calorimetry (DSC), thermogravimetry (TGA), dynamic mechanical analysis (DMA), Fourier Transform Infrared Spectroscopy (FTIR) and scanning electron microscopy (SEM) techniques were employed to monitor the effect mechanical recycling at each melt extrusion cycle. Tensile and impact strength results showed that PBAT and PBAT-TPS biocomposite were mechanical recyclable for at least eight cycles and this was comparable to LDPE recyclability performance. In contrast, neat PBS, PLA, and PBAT-PBS blend were found to be melt extrudable only up to six cycles as the mechanical properties declined with the increase of reprocessing cycles. MFI tests suggest that molecular weight of PBAT and PBAT-TPS were not significantly affected by multiple extrusion cycles while the melt flow properties of PBS, PLA, and PBAT-PBS samples were affected from third cycle. DSC, TGA, and DMA demonstrated that PBAT and PBAT-TPS were more thermo-mechanically stable than PBS, PLA, and PBAT-PBS blend. FTIR spectroscopy results showed that the chemical structure of both PBAT and PBAT-TPS were unaffected by the multiple recycling cycles typically indicated by characteristic peak vibrations bands of C=O and C-O around 1710 cm-1 and 1046-1100 cm-1, respectively. SEM micrographs of PBS, PLA, and PBAT-PBS clearly evidenced the degradation of the biopolymers by severely fractured morphology as a result multiple reprocessing cycle.The rate of aerobic biodegradation for PBAT-PBS and PBAT-PLA blends was examined under controlled home and industrial composting using the CO2 evolution respirometric method. FTIR, DSC, TGA, X-ray diffraction analysis (XRD), and SEM were employed to monitor the changes in the structural, chemical, thermal, and morphological characteristics of the biopolymer blends before and after biodegradation. The biodegradation tests showed that PBAT-PBS and PBAT-PLA blends exhibited higher degradation rates under industrial composting conditions than under home composting conditions. The increased intensity of hydroxyl and carbonyl absorption bands on the FTIR spectra confirmed that the biodegradation process occurred. SEM revealed that there was microbial colony formation and disintegration on the surfaces of the biopolymer blends. Moreover, abiotic degradation results suggested that thermal and hydrolytic conditions influence the degradation process than sunlight exposure. Additionally, aquatic biodegradation results showed that PBAT-PBS blend and PBAT-TPS composite undergo a higher rate of biodegradation as compared to PBAT, PBS, and PLA.The results obtained from this research work conclude that biobased biodegradable polymers can be mechanically recycled, and they are suitable for biological degradation in industrial composting, home composting and marine environment. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Nomadolo, Nomvuyo Elizabeth
- Date: 2023-12
- Subjects: Polymers , Polymeric composites , Biopolymers
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62539 , vital:72822
- Description: The present research aimed at investigating mechanical recyclability and studying the potential biotic and abiotic degradation behaviors of biobased biodegradable polymers in different environmental conditions. The mechanical recyclability tests monitored the effect of multiple reprocessing on the mechanical, thermal, physical, chemical, and morphological properties of poly (butylene adipate-co-terephthalate) (PBAT), poly (butylene succinate) (PBS), poly (lactic acid) (PLA), PBAT-PBS blend, and PBAT-thermoplastic starch (TPS) composite. Low-density polyethylene (LDPE), a conventional non-biodegradable plastic, was also monitored for comparison studies. The mechanical recyclability tests were carried out by eight melt extrusion cycles using twin-screw extrusion and injection molding processing techniques. Tensile testing, impact analysis, melt flow index test (MFI), differential scanning calorimetry (DSC), thermogravimetry (TGA), dynamic mechanical analysis (DMA), Fourier Transform Infrared Spectroscopy (FTIR) and scanning electron microscopy (SEM) techniques were employed to monitor the effect mechanical recycling at each melt extrusion cycle. Tensile and impact strength results showed that PBAT and PBAT-TPS biocomposite were mechanical recyclable for at least eight cycles and this was comparable to LDPE recyclability performance. In contrast, neat PBS, PLA, and PBAT-PBS blend were found to be melt extrudable only up to six cycles as the mechanical properties declined with the increase of reprocessing cycles. MFI tests suggest that molecular weight of PBAT and PBAT-TPS were not significantly affected by multiple extrusion cycles while the melt flow properties of PBS, PLA, and PBAT-PBS samples were affected from third cycle. DSC, TGA, and DMA demonstrated that PBAT and PBAT-TPS were more thermo-mechanically stable than PBS, PLA, and PBAT-PBS blend. FTIR spectroscopy results showed that the chemical structure of both PBAT and PBAT-TPS were unaffected by the multiple recycling cycles typically indicated by characteristic peak vibrations bands of C=O and C-O around 1710 cm-1 and 1046-1100 cm-1, respectively. SEM micrographs of PBS, PLA, and PBAT-PBS clearly evidenced the degradation of the biopolymers by severely fractured morphology as a result multiple reprocessing cycle.The rate of aerobic biodegradation for PBAT-PBS and PBAT-PLA blends was examined under controlled home and industrial composting using the CO2 evolution respirometric method. FTIR, DSC, TGA, X-ray diffraction analysis (XRD), and SEM were employed to monitor the changes in the structural, chemical, thermal, and morphological characteristics of the biopolymer blends before and after biodegradation. The biodegradation tests showed that PBAT-PBS and PBAT-PLA blends exhibited higher degradation rates under industrial composting conditions than under home composting conditions. The increased intensity of hydroxyl and carbonyl absorption bands on the FTIR spectra confirmed that the biodegradation process occurred. SEM revealed that there was microbial colony formation and disintegration on the surfaces of the biopolymer blends. Moreover, abiotic degradation results suggested that thermal and hydrolytic conditions influence the degradation process than sunlight exposure. Additionally, aquatic biodegradation results showed that PBAT-PBS blend and PBAT-TPS composite undergo a higher rate of biodegradation as compared to PBAT, PBS, and PLA.The results obtained from this research work conclude that biobased biodegradable polymers can be mechanically recycled, and they are suitable for biological degradation in industrial composting, home composting and marine environment. , Thesis (MSc) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Psychobiographical study of Daisy De Melker
- Authors: Moodley, Kerisha
- Date: 2023-12
- Subjects: Psychobiographical study , Antisocial , Personality dynamics
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62913 , vital:73067
- Description: Daisy Louisa C. de Melker, born on 1 June 1886, was a qualified nurse who is famously known to have poisoned two husbands with strychnine in order to receive life insurance money while living in Turffontein, Johannesburg. Later on, she poisoned her only son with arsenic for reasons which are still unclear, and he passed away soon after. She is notoriously known in history to be the second woman to have been hanged in South Africa due to receiving the death penalty. The primary aim of the study is to explore the life of de Melker to gain an understanding of her personality development, with the aim of acquiring insight into the motivation behind her behaviour. The secondary aim includes exploring apparent Cluster B personality traits. The study is exploratory-descriptive in nature and the subject was chosen through purposive sampling. The study uses a qualitative, psycho-biographical, single-case research design to study De Melker, in order to explore and describe the personality development of her from the theoretical perspectives of Kernberg’s Object Relations Theory. This specific theory was chosen as it allowed the researcher to explore Daisy de Melker’s early childhood and upbringing that impacted the formation of ‘internal representations’ of herself and other people. The theory suggests that when there is a lack of integration of object relations, which is made up of internal and external representations, it may result in the development of a personality disorder, as it places a focus on relationships being more crucial to personality development than individual drives and abilities. Data was collected by triangulating multiple sources of information. Miles and Huberman’s (1994) strategy were used to analyse the data according to three steps, which include data reduction, data display, and conclusion drawing and verification. The significance of doing a psychobiography study lies in merging of personality psychology and historical evidence which represents a growing field in the realm of biography and provides insight into personality development through a theoretical framework. , Thesis (Ma) -- Faculty of Health Science. 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Moodley, Kerisha
- Date: 2023-12
- Subjects: Psychobiographical study , Antisocial , Personality dynamics
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62913 , vital:73067
- Description: Daisy Louisa C. de Melker, born on 1 June 1886, was a qualified nurse who is famously known to have poisoned two husbands with strychnine in order to receive life insurance money while living in Turffontein, Johannesburg. Later on, she poisoned her only son with arsenic for reasons which are still unclear, and he passed away soon after. She is notoriously known in history to be the second woman to have been hanged in South Africa due to receiving the death penalty. The primary aim of the study is to explore the life of de Melker to gain an understanding of her personality development, with the aim of acquiring insight into the motivation behind her behaviour. The secondary aim includes exploring apparent Cluster B personality traits. The study is exploratory-descriptive in nature and the subject was chosen through purposive sampling. The study uses a qualitative, psycho-biographical, single-case research design to study De Melker, in order to explore and describe the personality development of her from the theoretical perspectives of Kernberg’s Object Relations Theory. This specific theory was chosen as it allowed the researcher to explore Daisy de Melker’s early childhood and upbringing that impacted the formation of ‘internal representations’ of herself and other people. The theory suggests that when there is a lack of integration of object relations, which is made up of internal and external representations, it may result in the development of a personality disorder, as it places a focus on relationships being more crucial to personality development than individual drives and abilities. Data was collected by triangulating multiple sources of information. Miles and Huberman’s (1994) strategy were used to analyse the data according to three steps, which include data reduction, data display, and conclusion drawing and verification. The significance of doing a psychobiography study lies in merging of personality psychology and historical evidence which represents a growing field in the realm of biography and provides insight into personality development through a theoretical framework. , Thesis (Ma) -- Faculty of Health Science. 2023
- Full Text:
- Date Issued: 2023-12
Pyrolysis of algal biomass and coal in a rotary kiln reactor: Pyrolysis behaviour, product distribution and kinetic analysis
- Authors: Nyoni, Bothwell
- Date: 2023-12
- Subjects: Algal biofuels , Biomass energy , Coal -- South Africa
- Language: English
- Type: Doctorate theses , text
- Identifier: http://hdl.handle.net/10948/62550 , vital:72823
- Description: There are two primary reasons why the global economy is gradually reducing its dependence on coal as an energy source. Firstly, coal reserves are finite, and while some argue that current reserves will last for generations, the reality is that coal is a non-renewable resource. Secondly, the emissions associated with coal usage have adverse effects on both the environment and human health. While European countries have adopted seemingly aggressive strategies to replace coal and other fossil fuels, South Africa and other developing nations face economic constraints that limit such actions. Fortunately, there are more conservative approaches that can be employed, one of which involves a gradual introduction of renewable energy sources into the energy grid. Wind, solar, and biomass currently stand as the major renewable energy sources under consideration. However, it's worth noting that the intermittent nature of wind and solar energy production poses a significant challenge. Biomass holds the potential to replace coal in retrofitted coal-fired plants. However, the unchecked utilisation of biomass can lead to deforestation and have adverse effects on the human and animal food supply chain, as many essential food items are derived from plants. The debate over using biomass as a fuel source, especially when some types of biomasses can serve as food for humans and animals, has been a subject of ongoing discussion. Furthermore, biomass exhibits a lower energy density when compared to coal. Combustion stands as the primary technology for converting coal into energy and is widely used in most coal-based power plants. Gasification, on the other hand, has been employed for years in South Africa as a coal-to-liquids technology to supplement transportation fuel requirements and reduce reliance on crude oil imports. Pyrolysis, too, has found application as a key method for obtaining high-energy coal char, serving both as an energy source and a reducing agent in blast furnaces for the steelmaking industry. Pyrolysis technologies are gaining popularity in biomass-to-liquids processes due to their simplicity. Currently, there is growing research interest in simultaneous pyrolysis of coal and biomass. The study presented in this thesis focuses on investigating the pyrolysis of Scenedesmus algae biomass and low-grade coal in a small-scale rotary kiln, with particular emphasis on the synthesised liquid products. Algae represent a unique type of biomass that can be cultivated in photo-bioreactors with minimal use of agricultural land. This suggests significant potential for large-scale cultivation of algae, and ongoing efforts are exploring strategies for the mass production of algal biomass.Firstly, pyrolysis studies were carried out via thermogravimetric analysis instruments. It was revealed that because of algae’s considerably higher volatile content and lower carbon content when compared to coal, the pyrolysis process of algal biomass occurred at a faster rate. The highest pyrolytic reactivity of algae was 0.41 mg/min occurring at approximately 290 ᵒC in comparison with coal’s 0.06 mg/min occurring in the approximate temperature range of 550 – 600 ᵒC. The magnitude of the reactivity of the blends depended on the coal/algae ratios used. Furthermore, kinetics analysis revealed that the overall pyrolytic decomposition of coal followed 2nd order kinetics with an activation energy of 81.8 kJ/mol. The decomposition of algae and coal-algae blends occurred in two stages; the first stage decomposition followed 2nd order kinetics with activation energies in the range 130.3 – 145.5 kJ/mol. The second stage decomposition of algae followed 1st order kinetics with an activation energy of 27.3 kJ/mol, whilst coal-algae blends followed 2nd order decomposition with an activation energy range of 69.4 – 74.2 kJ/mol. Secondly, pyrolysis studies were carried out in a rotary kiln reactor wherefrom the char products were collected, and pyrolytic gases condensed to obtain pyroligneous liquid. It was found that the composition of oils synthesised from the pyrolysis of coal was rich in paraffins (52.6 % at 550 ᵒC), however the yield of oil from the pyrolysis of coal was low (6.9 %). Oils from algae and coal-algae blends were dominated by alcohols, fatty acids, fatty acid esters and poly-cyclic aromatic compounds. For example, the most abundant compounds in algae oil produced at 550 ᵒC were fatty acid esters (28.8 %), alcohols (17.6 %), fatty acids (10.8 %) and unsaturated aliphatics (10.7 %); the oil yield obtained from pyrolysis of algae was 40 %. The yields and composition of oils obtained from coal-algae blends were linked to individual contributions from coal and algae, especially at 550 ᵒC; however, the contributions were not proportional due to synergistic effects. This kind of study will contribute to the already existing but limited literature on coal-algae pyrolysis. Furthermore, this study demonstrates the potential of using low-grade coals (an abundant resource in Southern Africa) in conjunction with algal biomass (a renewable resource), in large-scale synthesis of liquid fuels and valuable chemicals via a simple pyrolysis process. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Nyoni, Bothwell
- Date: 2023-12
- Subjects: Algal biofuels , Biomass energy , Coal -- South Africa
- Language: English
- Type: Doctorate theses , text
- Identifier: http://hdl.handle.net/10948/62550 , vital:72823
- Description: There are two primary reasons why the global economy is gradually reducing its dependence on coal as an energy source. Firstly, coal reserves are finite, and while some argue that current reserves will last for generations, the reality is that coal is a non-renewable resource. Secondly, the emissions associated with coal usage have adverse effects on both the environment and human health. While European countries have adopted seemingly aggressive strategies to replace coal and other fossil fuels, South Africa and other developing nations face economic constraints that limit such actions. Fortunately, there are more conservative approaches that can be employed, one of which involves a gradual introduction of renewable energy sources into the energy grid. Wind, solar, and biomass currently stand as the major renewable energy sources under consideration. However, it's worth noting that the intermittent nature of wind and solar energy production poses a significant challenge. Biomass holds the potential to replace coal in retrofitted coal-fired plants. However, the unchecked utilisation of biomass can lead to deforestation and have adverse effects on the human and animal food supply chain, as many essential food items are derived from plants. The debate over using biomass as a fuel source, especially when some types of biomasses can serve as food for humans and animals, has been a subject of ongoing discussion. Furthermore, biomass exhibits a lower energy density when compared to coal. Combustion stands as the primary technology for converting coal into energy and is widely used in most coal-based power plants. Gasification, on the other hand, has been employed for years in South Africa as a coal-to-liquids technology to supplement transportation fuel requirements and reduce reliance on crude oil imports. Pyrolysis, too, has found application as a key method for obtaining high-energy coal char, serving both as an energy source and a reducing agent in blast furnaces for the steelmaking industry. Pyrolysis technologies are gaining popularity in biomass-to-liquids processes due to their simplicity. Currently, there is growing research interest in simultaneous pyrolysis of coal and biomass. The study presented in this thesis focuses on investigating the pyrolysis of Scenedesmus algae biomass and low-grade coal in a small-scale rotary kiln, with particular emphasis on the synthesised liquid products. Algae represent a unique type of biomass that can be cultivated in photo-bioreactors with minimal use of agricultural land. This suggests significant potential for large-scale cultivation of algae, and ongoing efforts are exploring strategies for the mass production of algal biomass.Firstly, pyrolysis studies were carried out via thermogravimetric analysis instruments. It was revealed that because of algae’s considerably higher volatile content and lower carbon content when compared to coal, the pyrolysis process of algal biomass occurred at a faster rate. The highest pyrolytic reactivity of algae was 0.41 mg/min occurring at approximately 290 ᵒC in comparison with coal’s 0.06 mg/min occurring in the approximate temperature range of 550 – 600 ᵒC. The magnitude of the reactivity of the blends depended on the coal/algae ratios used. Furthermore, kinetics analysis revealed that the overall pyrolytic decomposition of coal followed 2nd order kinetics with an activation energy of 81.8 kJ/mol. The decomposition of algae and coal-algae blends occurred in two stages; the first stage decomposition followed 2nd order kinetics with activation energies in the range 130.3 – 145.5 kJ/mol. The second stage decomposition of algae followed 1st order kinetics with an activation energy of 27.3 kJ/mol, whilst coal-algae blends followed 2nd order decomposition with an activation energy range of 69.4 – 74.2 kJ/mol. Secondly, pyrolysis studies were carried out in a rotary kiln reactor wherefrom the char products were collected, and pyrolytic gases condensed to obtain pyroligneous liquid. It was found that the composition of oils synthesised from the pyrolysis of coal was rich in paraffins (52.6 % at 550 ᵒC), however the yield of oil from the pyrolysis of coal was low (6.9 %). Oils from algae and coal-algae blends were dominated by alcohols, fatty acids, fatty acid esters and poly-cyclic aromatic compounds. For example, the most abundant compounds in algae oil produced at 550 ᵒC were fatty acid esters (28.8 %), alcohols (17.6 %), fatty acids (10.8 %) and unsaturated aliphatics (10.7 %); the oil yield obtained from pyrolysis of algae was 40 %. The yields and composition of oils obtained from coal-algae blends were linked to individual contributions from coal and algae, especially at 550 ᵒC; however, the contributions were not proportional due to synergistic effects. This kind of study will contribute to the already existing but limited literature on coal-algae pyrolysis. Furthermore, this study demonstrates the potential of using low-grade coals (an abundant resource in Southern Africa) in conjunction with algal biomass (a renewable resource), in large-scale synthesis of liquid fuels and valuable chemicals via a simple pyrolysis process. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Spatial patterns of human-elephant conflict and elephant space-use in Liwonde National Park, Malawi
- Authors: Voges, Mignon
- Date: 2023-12
- Subjects: Human-animal relationships , Wildlife management -- Malawi , Wildlife conservation -- Malawi
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62721 , vital:72933
- Description: Human-wildlife conflict (HWC) is a prevailing issue worldwide, threatening the livelihood of the affected human communities, and the persistence of wildlife populations and habitat. Human-elephant conflict (HEC) is particularly challenging, given the damage or harm these large animals can cause to human communities. Moreover, HEC threatens the safety of elephant populations as elephants can be injured or killed when people retaliate. Several studies have therefore been conducted to investigate HEC spatiotemporal patterns in order to better understand it and to develop mitigation measures. These studies predominantly used non-spatial statistics or global regressions to investigate HEC patterns and drivers. The general understanding of HEC patterns and drivers are therefore based on general predictions derived from global regressions that assume stationarity of the relationship between HEC and its drivers across the landscape. Previous studies using global regressions may therefore have missed or misidentified important drivers of the spatial patterns, making the resultant global regression models misleading. The aim of this study was therefore to investigate the spatiotemporal patterns and drivers of HEC adjacent to Liwonde National Park using spatial analytical tools that account for the spatial nature of the data and the spatial variation in conflict drivers across a landscape. Using a Geographically Weighted Regression, I identified vegetation quality, season, and distance to seasonal water as drivers of HEC hotspots adjacent to Liwonde. HEC was more intense in areas with higher quality vegetation (compared to vegetation quality inside the Park) and areas that were closer to seasonal water. The relationship between HEC hotspots and these drivers varied at the patch-level and according to season. My findings suggest that HEC is more complex than the general patterns described with global regressions. The localized patterns and drivers of HEC hotspots identified, reflect trade-off between elephants securing rewards (crops), while reducing risks (encountering humans), as expected under forage optimality models. The understanding of elephant adaptation and trade-offs in human landscapes gained from my study, along with the approach I have adopted, can be applied to other HEC study sites, and help guide HEC management in Liwonde. This approach can also be applied to analysis of other forms of HWC, greatly improving HWC mitigation. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Voges, Mignon
- Date: 2023-12
- Subjects: Human-animal relationships , Wildlife management -- Malawi , Wildlife conservation -- Malawi
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62721 , vital:72933
- Description: Human-wildlife conflict (HWC) is a prevailing issue worldwide, threatening the livelihood of the affected human communities, and the persistence of wildlife populations and habitat. Human-elephant conflict (HEC) is particularly challenging, given the damage or harm these large animals can cause to human communities. Moreover, HEC threatens the safety of elephant populations as elephants can be injured or killed when people retaliate. Several studies have therefore been conducted to investigate HEC spatiotemporal patterns in order to better understand it and to develop mitigation measures. These studies predominantly used non-spatial statistics or global regressions to investigate HEC patterns and drivers. The general understanding of HEC patterns and drivers are therefore based on general predictions derived from global regressions that assume stationarity of the relationship between HEC and its drivers across the landscape. Previous studies using global regressions may therefore have missed or misidentified important drivers of the spatial patterns, making the resultant global regression models misleading. The aim of this study was therefore to investigate the spatiotemporal patterns and drivers of HEC adjacent to Liwonde National Park using spatial analytical tools that account for the spatial nature of the data and the spatial variation in conflict drivers across a landscape. Using a Geographically Weighted Regression, I identified vegetation quality, season, and distance to seasonal water as drivers of HEC hotspots adjacent to Liwonde. HEC was more intense in areas with higher quality vegetation (compared to vegetation quality inside the Park) and areas that were closer to seasonal water. The relationship between HEC hotspots and these drivers varied at the patch-level and according to season. My findings suggest that HEC is more complex than the general patterns described with global regressions. The localized patterns and drivers of HEC hotspots identified, reflect trade-off between elephants securing rewards (crops), while reducing risks (encountering humans), as expected under forage optimality models. The understanding of elephant adaptation and trade-offs in human landscapes gained from my study, along with the approach I have adopted, can be applied to other HEC study sites, and help guide HEC management in Liwonde. This approach can also be applied to analysis of other forms of HWC, greatly improving HWC mitigation. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Management, 2023
- Full Text:
- Date Issued: 2023-12
Statistical analysis of hydrogeochemical data from fractured rock aquifers around Beaufort West, South Africa
- Authors: Berkland, James
- Date: 2023-12
- Subjects: Groundwater -- South Africa -- Beaufort West , Hydrogeology -- South Africa -- Beaufort West , Aquifers -- South Africa -- Beaufort West
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62442 , vital:72736
- Description: Knowledge surrounding the procedures and protocols related to groundwater sampling are currently limited. In particular, the sampling of radioactive elements from fractured rock aquifers is poorly understood and in need of further research. The aim of this study is to provide a comparative insight into groundwater sampling methods used for the sampling of major and minor elements as well as trace elements within fractured rock aquifers in the immediate vicinity of Beaufort West. The influence of sampling source, seasonality, and vertical flows on sample results are observed. Furthermore, the importance of historical datasets is raised. Aims of this study were achieved by making use of historical data from numerous studies that were conducted near the Karoo town of Beaufort West. Potential profitable uranium deposits saw a great influx of research into the geology, topography, climate and hydrogeology. Synthesising data from these historical research papers has provided valuable information regarding the influences of sampling procedures on the results. A total of 695 well data samples were analysed from four studies collected from farms around Beaufort West. The importance of adequately purging a well prior to sampling cannot be stressed enough. There are minimal chemical differences between sampling boreholes and wind pumps, however there was a noticeable difference in the inter-relationships between major chemical elements. Groundwater samplers were found to be contaminated with Zinc and Copper attributed to wind pump fittings. Boreholes were also analysed to observe any changes in depth. Sodium, temperature and uranium had little to no changes with depth due to the homogenous nature of the borehole water. Principal component analysis was conducted on 159 groundwater samples comprised of 13 variables. These samples were reduced to four principal components (PC) which explained a total of 91.09% of the total variance. Factor one explained 61.99% of the total variance and was strongly associated with water-type and lithology while factor two (13.57%) shows the potential relationship between molybdenum and uranium as well as possible copper contamination as a result of wind pump and borehole fittings. Further research should be conducted by carrying out multiple sampling procedures on a selection of controlled wells to determine the best applicable sampling procedures. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Berkland, James
- Date: 2023-12
- Subjects: Groundwater -- South Africa -- Beaufort West , Hydrogeology -- South Africa -- Beaufort West , Aquifers -- South Africa -- Beaufort West
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62442 , vital:72736
- Description: Knowledge surrounding the procedures and protocols related to groundwater sampling are currently limited. In particular, the sampling of radioactive elements from fractured rock aquifers is poorly understood and in need of further research. The aim of this study is to provide a comparative insight into groundwater sampling methods used for the sampling of major and minor elements as well as trace elements within fractured rock aquifers in the immediate vicinity of Beaufort West. The influence of sampling source, seasonality, and vertical flows on sample results are observed. Furthermore, the importance of historical datasets is raised. Aims of this study were achieved by making use of historical data from numerous studies that were conducted near the Karoo town of Beaufort West. Potential profitable uranium deposits saw a great influx of research into the geology, topography, climate and hydrogeology. Synthesising data from these historical research papers has provided valuable information regarding the influences of sampling procedures on the results. A total of 695 well data samples were analysed from four studies collected from farms around Beaufort West. The importance of adequately purging a well prior to sampling cannot be stressed enough. There are minimal chemical differences between sampling boreholes and wind pumps, however there was a noticeable difference in the inter-relationships between major chemical elements. Groundwater samplers were found to be contaminated with Zinc and Copper attributed to wind pump fittings. Boreholes were also analysed to observe any changes in depth. Sodium, temperature and uranium had little to no changes with depth due to the homogenous nature of the borehole water. Principal component analysis was conducted on 159 groundwater samples comprised of 13 variables. These samples were reduced to four principal components (PC) which explained a total of 91.09% of the total variance. Factor one explained 61.99% of the total variance and was strongly associated with water-type and lithology while factor two (13.57%) shows the potential relationship between molybdenum and uranium as well as possible copper contamination as a result of wind pump and borehole fittings. Further research should be conducted by carrying out multiple sampling procedures on a selection of controlled wells to determine the best applicable sampling procedures. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2023
- Full Text:
- Date Issued: 2023-12
Study on the Isixhosa elder’s perspective on mental illness in buffalo city municipality, Eastern Cape, South Africa
- Bam, Zimkhitha Yolisa Nokubulela
- Authors: Bam, Zimkhitha Yolisa Nokubulela
- Date: 2023-12
- Subjects: Xhosa language -- Eastern Cape , Mental illness
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62827 , vital:73046
- Description: Generally, the elders in the family are usually responsible for their families, including the care and socialisation of younger members. With the increasing number of mental illness cases being reported, not only in South Africa but the rest of the world, it is imperative to explore what the elderly understand about mental illnesses, given that they may have insights that might be useful. This study aimed to explore the perceptions of elderly members in the isiXhosa community of the Buffalo City Metropolitan Municipality in the Eastern Cape province, regarding their understanding of mental illnesses. The researcher employed an exploratory-descriptive, qualitative design and adopted Lincoln and Guba’s model of trustworthiness. Participants were recruited through the use of snowball and purposive sampling and the data was gathered through one-on-one interviews conducted with elderly isiXhosa individuals. Thematic analysis was used as a means of data analysis, by following data analysis method by Braun and Clarke. The following themes were identified during the study; Limited understanding about mental illness, varied causes of mental illness and a generationally linked understanding of mental illness. The findings reflected the participants understanding of what mental illness is and the causes of it and suggest that more research is required to understand the cultural influences on perceptions of mental illness. , Thesis (Ma) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12
- Authors: Bam, Zimkhitha Yolisa Nokubulela
- Date: 2023-12
- Subjects: Xhosa language -- Eastern Cape , Mental illness
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/62827 , vital:73046
- Description: Generally, the elders in the family are usually responsible for their families, including the care and socialisation of younger members. With the increasing number of mental illness cases being reported, not only in South Africa but the rest of the world, it is imperative to explore what the elderly understand about mental illnesses, given that they may have insights that might be useful. This study aimed to explore the perceptions of elderly members in the isiXhosa community of the Buffalo City Metropolitan Municipality in the Eastern Cape province, regarding their understanding of mental illnesses. The researcher employed an exploratory-descriptive, qualitative design and adopted Lincoln and Guba’s model of trustworthiness. Participants were recruited through the use of snowball and purposive sampling and the data was gathered through one-on-one interviews conducted with elderly isiXhosa individuals. Thematic analysis was used as a means of data analysis, by following data analysis method by Braun and Clarke. The following themes were identified during the study; Limited understanding about mental illness, varied causes of mental illness and a generationally linked understanding of mental illness. The findings reflected the participants understanding of what mental illness is and the causes of it and suggest that more research is required to understand the cultural influences on perceptions of mental illness. , Thesis (Ma) -- Faculty of Health Science, 2023
- Full Text:
- Date Issued: 2023-12