Robot Rights, an approach appealing to Animal Rights Theory
- Authors: Millin, Murray David
- Date: 2021-10-29
- Subjects: Artificial intelligence , Singer, Peter, 1946- , Dennett, D C (Daniel Clement) , Animal rights , Ethics , Asimov, Isaac, 1920-1992 Criticism and interpretation , Asimov, Isaac, 1920-1992. Bicentennial man , Asimov, Isaac, 1920-1992. Sally , Preference utilitarianism
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191854 , vital:45172
- Description: This thesis proposes that Peter Singer’s theory of preference utilitarianism, which is designed to be universally applicable to humans and animals, can be applied to robots of a particular kind — such as those seen in Isaac Asimov’s work. I shall do this by using Singer’s conception of interests as a framework, and appealing to Daniel Dennett’s intentional stance to deal with methodological issues about other minds. I shall then apply those theories to Isaac Asimov’s Sally and The Bicentennial Man. These two narratives show the importance of the intentional stance as an ethical tool and provide an example of how we might talk about the interests of a robot. Sally’s behaviour and ethical status is examined according to how she is perceived, and so I shall investigate how various persons engage with her and why they do so in those manners. This narrative demonstrates the value of the intentional and design stance as methods to approach other minds problems with regards to ethical status. The Bicentennial Man’s Andrew allows us to look for interests in a more concrete way. I look to see how he situates himself in his world, as well as investigate how and why he makes the demand to be morally considerable. This will be done by examining his creativity, personal development and drive for mortality throughout the narrative. , Thesis (MA) -- Faculty of Humanities, Philosophy, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Millin, Murray David
- Date: 2021-10-29
- Subjects: Artificial intelligence , Singer, Peter, 1946- , Dennett, D C (Daniel Clement) , Animal rights , Ethics , Asimov, Isaac, 1920-1992 Criticism and interpretation , Asimov, Isaac, 1920-1992. Bicentennial man , Asimov, Isaac, 1920-1992. Sally , Preference utilitarianism
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191854 , vital:45172
- Description: This thesis proposes that Peter Singer’s theory of preference utilitarianism, which is designed to be universally applicable to humans and animals, can be applied to robots of a particular kind — such as those seen in Isaac Asimov’s work. I shall do this by using Singer’s conception of interests as a framework, and appealing to Daniel Dennett’s intentional stance to deal with methodological issues about other minds. I shall then apply those theories to Isaac Asimov’s Sally and The Bicentennial Man. These two narratives show the importance of the intentional stance as an ethical tool and provide an example of how we might talk about the interests of a robot. Sally’s behaviour and ethical status is examined according to how she is perceived, and so I shall investigate how various persons engage with her and why they do so in those manners. This narrative demonstrates the value of the intentional and design stance as methods to approach other minds problems with regards to ethical status. The Bicentennial Man’s Andrew allows us to look for interests in a more concrete way. I look to see how he situates himself in his world, as well as investigate how and why he makes the demand to be morally considerable. This will be done by examining his creativity, personal development and drive for mortality throughout the narrative. , Thesis (MA) -- Faculty of Humanities, Philosophy, 2021
- Full Text:
- Date Issued: 2021-10-29
Role of the Amathole Marine Protected Area in protecting vulnerable and threatened reef fish
- Phillips, Moraea Megan Taberer
- Authors: Phillips, Moraea Megan Taberer
- Date: 2021-10-29
- Subjects: Reef fishes South Africa Amathole District Municipality , Reef fishes Conservation South Africa Amathole District Municipality , Reef ecology South Africa Amathole District Municipality , Rare fishes South Africa Amathole District Municipality , Fish populations South Africa Amathole District Municipality Monitoring , Fish declines South Africa Amathole District Municipality , Underwater videography in wildlife monitoring South Africa Amathole District Municipality , Amathole Marine Protected Area , Petrus rupestris (Red Steenbras) , Polysteganus undulosus (Seventyfour seabream) , Chrysoblephus cristiceps (Daggerhead seabream)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192152 , vital:45200
- Description: The Amathole Marine Protected Area (MPA) was first established on a voluntary basis in the 1980’s by local ski-boat fishermen and comprised three small no-take areas near East London. In 2011, the areas received official recognition as the Amathole MPA and in 2019 an offshore extension was granted, increasing the area covered from 250 km2 to over 4000 km2. Though the inshore Amathole MPA has benefitted from decades longer of reprieve from fishing activity than the offshore MPA, it is limited in both its coastal and depth extent, placing in doubt its capacity to provide meaningful protection to several heavily threatened target species. Among the numerous endemic Sparids for which the Amathole region constitutes a vital portion of their distributional range are red steenbras (Petrus rupestris), seventyfour (Polysteganus undulosus), and dageraad (Chrysoblephus cristiceps). The stocks of all three species have collapsed and urgent intervention has been recommended to enable their recovery, including protection in strategically placed MPAs. The offshore Amathole MPA covers an extensive portion of prime habitat for these and other species, but no formal research has been carried out on fish assemblages in the region. As such, data to substantiate the benefits of the inshore Amathole MPA and to provide a baseline reference for the offshore MPA are lacking. This study made use of baited remote underwater stereo-video systems (stereo-BRUVS) to survey fish assemblages in the inshore Amathole MPA, adjacent inshore exploited areas, and exploited areas seaward of the inshore MPA. Sampling was carried out in 2015 and 2016, prior to the establishment of the offshore Amathole MPA. Fish assemblages from the inshore MPA were compared with those from adjacent exploited areas within the same depth range and from the offshore zone between 76 and 112 m depth. Within the inshore zone, biomass and abundance of target species were greater inside the MPA than in adjacent exploited areas, with vulnerable fisheries species showing the strongest response to protection. Offshore assemblages consisted of fewer species and fewer fish overall than those from the inshore zone but were dominated by larger individuals and those from higher trophic levels. The size of C. cristiceps was consistent across the sampled depth range but abundance of this species declined rapidly at depths of more than 60 m. Within the inshore zone, both abundance and size of C. cristiceps were greater in the MPA than in adjacent exploited areas. The size of P. rupestris was consistent across the sampled depth range and between protected and exploited areas, but this species was considerably more abundant offshore. Where P. rupestris was detected inshore it was almost exclusively in the MPA. No difference in the size or abundance of P. undulosus was found between the inshore MPA and inshore Abstract exploited areas, but both measures were found to increase with depth, with reproductive-sized adults restricted to the offshore zone. Despite its limited benefits for larger species, the inshore Amathole MPA is a critical refuge for smaller and more resident species like C. cristiceps, demonstrating the possibilities for conservation and management of endangered species in small MPAs. Baseline abundance and size measures for P. rupestris and P. undulosus recorded here indicate that the offshore extension of the Amathole MPA is ideally situated to protect spawner stock of these species and potentially contribute to the recovery of their stocks across a wider distributional range. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Phillips, Moraea Megan Taberer
- Date: 2021-10-29
- Subjects: Reef fishes South Africa Amathole District Municipality , Reef fishes Conservation South Africa Amathole District Municipality , Reef ecology South Africa Amathole District Municipality , Rare fishes South Africa Amathole District Municipality , Fish populations South Africa Amathole District Municipality Monitoring , Fish declines South Africa Amathole District Municipality , Underwater videography in wildlife monitoring South Africa Amathole District Municipality , Amathole Marine Protected Area , Petrus rupestris (Red Steenbras) , Polysteganus undulosus (Seventyfour seabream) , Chrysoblephus cristiceps (Daggerhead seabream)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192152 , vital:45200
- Description: The Amathole Marine Protected Area (MPA) was first established on a voluntary basis in the 1980’s by local ski-boat fishermen and comprised three small no-take areas near East London. In 2011, the areas received official recognition as the Amathole MPA and in 2019 an offshore extension was granted, increasing the area covered from 250 km2 to over 4000 km2. Though the inshore Amathole MPA has benefitted from decades longer of reprieve from fishing activity than the offshore MPA, it is limited in both its coastal and depth extent, placing in doubt its capacity to provide meaningful protection to several heavily threatened target species. Among the numerous endemic Sparids for which the Amathole region constitutes a vital portion of their distributional range are red steenbras (Petrus rupestris), seventyfour (Polysteganus undulosus), and dageraad (Chrysoblephus cristiceps). The stocks of all three species have collapsed and urgent intervention has been recommended to enable their recovery, including protection in strategically placed MPAs. The offshore Amathole MPA covers an extensive portion of prime habitat for these and other species, but no formal research has been carried out on fish assemblages in the region. As such, data to substantiate the benefits of the inshore Amathole MPA and to provide a baseline reference for the offshore MPA are lacking. This study made use of baited remote underwater stereo-video systems (stereo-BRUVS) to survey fish assemblages in the inshore Amathole MPA, adjacent inshore exploited areas, and exploited areas seaward of the inshore MPA. Sampling was carried out in 2015 and 2016, prior to the establishment of the offshore Amathole MPA. Fish assemblages from the inshore MPA were compared with those from adjacent exploited areas within the same depth range and from the offshore zone between 76 and 112 m depth. Within the inshore zone, biomass and abundance of target species were greater inside the MPA than in adjacent exploited areas, with vulnerable fisheries species showing the strongest response to protection. Offshore assemblages consisted of fewer species and fewer fish overall than those from the inshore zone but were dominated by larger individuals and those from higher trophic levels. The size of C. cristiceps was consistent across the sampled depth range but abundance of this species declined rapidly at depths of more than 60 m. Within the inshore zone, both abundance and size of C. cristiceps were greater in the MPA than in adjacent exploited areas. The size of P. rupestris was consistent across the sampled depth range and between protected and exploited areas, but this species was considerably more abundant offshore. Where P. rupestris was detected inshore it was almost exclusively in the MPA. No difference in the size or abundance of P. undulosus was found between the inshore MPA and inshore Abstract exploited areas, but both measures were found to increase with depth, with reproductive-sized adults restricted to the offshore zone. Despite its limited benefits for larger species, the inshore Amathole MPA is a critical refuge for smaller and more resident species like C. cristiceps, demonstrating the possibilities for conservation and management of endangered species in small MPAs. Baseline abundance and size measures for P. rupestris and P. undulosus recorded here indicate that the offshore extension of the Amathole MPA is ideally situated to protect spawner stock of these species and potentially contribute to the recovery of their stocks across a wider distributional range. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-10-29
Schema modes in eating disorders: an interpretative phenomenological analysis
- Authors: Bowker, Chantal Ann
- Date: 2021-10-29
- Subjects: Eating disorders , Anorexia nervosa , Bulimia , Compulsive eating , Schema-focused cognitive therapy , Interpretative phenomenological analysis (IPA)
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/196072 , vital:45723 , DOI 10.21504/10962/196072
- Description: The DSM-5 prevalence rate of anorexia nervosa is 0.4%, bulimia nervosa is 1% to 1.5%, and binge eating disorder is 1.6% (American Psychiatric Association, 2013). Although treatment approaches for eating disorders have high drop-out rates and low rates of recovery, treatment modalities that address childhood factors contributing to the eating disorder, as well as the eating disorder behaviours, have better outcomes. Schema therapy is an integrative approach that has been used for the treatment of eating disorders for more than a decade. Central features in schema therapy include the identification of early maladaptive schemas arising from unmet needs and schema modes. Schema modes, composed of schemas and coping mechanisms, are active for an individual at a particular time in response to triggers in the environment (Brown et al., 2016). Identifying an individual’s modes is a crucial aspect that reflects the underlying structure of the individual’s creation of reality. A phenomenological understanding of the modes is essential for developing a case conceptualisation and treatment plan. Differences exist in the naming and description of modes in the current schema therapy literature, which suggests the need for a phenomenological investigation of these structures. This research study used a mostly qualitative approach, in the form of clinical interviews, substantiated by questionnaires, to examine schema modes. Case presentations using the schema therapy model are provided for five women with either anorexia nervosa, bulimia nervosa or binge eating disorder. Then, through a process of interpretative phenomenological analysis, specific modes are examined as to how they are experienced by the participants and influence their behaviour. The features of schema modes in these clinical cases are compared to the existing literature to extend the understanding of schema modes in eating disorders. The participants’ experiences revealed that they had schema modes in common, regardless of the eating disorder presentation, but that the features of the individual modes varied. Modes found in the current literature such as the Detached Self-Soother and Perfectionist Overcontroller coping mode, were found in all the participants. Four of the five participants had an Eating Disordered Overcontroller mode. Features consistent with the existing descriptions of the Perfectionist Overcontroller, Eating Disordered Overcontroller and Detached Self-Soother modes were noted, and new features were identified. The Perfectionist Overcontroller and Eating Disordered Overcontroller have been presented here as complex composite modes with sub-modes that work together in a coherent way in the service of the same project (Edwards, 2020b). Twenty-three features are identified in the parent modes. Blended parent modes, with multiple features active in a situation, were described. The blended parent modes expand on the existing literature on parent modes. The findings in this research support and extend the mode structure identified in the schema therapy theory, and highlight the idiosyncratic nature of the modes. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Bowker, Chantal Ann
- Date: 2021-10-29
- Subjects: Eating disorders , Anorexia nervosa , Bulimia , Compulsive eating , Schema-focused cognitive therapy , Interpretative phenomenological analysis (IPA)
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/196072 , vital:45723 , DOI 10.21504/10962/196072
- Description: The DSM-5 prevalence rate of anorexia nervosa is 0.4%, bulimia nervosa is 1% to 1.5%, and binge eating disorder is 1.6% (American Psychiatric Association, 2013). Although treatment approaches for eating disorders have high drop-out rates and low rates of recovery, treatment modalities that address childhood factors contributing to the eating disorder, as well as the eating disorder behaviours, have better outcomes. Schema therapy is an integrative approach that has been used for the treatment of eating disorders for more than a decade. Central features in schema therapy include the identification of early maladaptive schemas arising from unmet needs and schema modes. Schema modes, composed of schemas and coping mechanisms, are active for an individual at a particular time in response to triggers in the environment (Brown et al., 2016). Identifying an individual’s modes is a crucial aspect that reflects the underlying structure of the individual’s creation of reality. A phenomenological understanding of the modes is essential for developing a case conceptualisation and treatment plan. Differences exist in the naming and description of modes in the current schema therapy literature, which suggests the need for a phenomenological investigation of these structures. This research study used a mostly qualitative approach, in the form of clinical interviews, substantiated by questionnaires, to examine schema modes. Case presentations using the schema therapy model are provided for five women with either anorexia nervosa, bulimia nervosa or binge eating disorder. Then, through a process of interpretative phenomenological analysis, specific modes are examined as to how they are experienced by the participants and influence their behaviour. The features of schema modes in these clinical cases are compared to the existing literature to extend the understanding of schema modes in eating disorders. The participants’ experiences revealed that they had schema modes in common, regardless of the eating disorder presentation, but that the features of the individual modes varied. Modes found in the current literature such as the Detached Self-Soother and Perfectionist Overcontroller coping mode, were found in all the participants. Four of the five participants had an Eating Disordered Overcontroller mode. Features consistent with the existing descriptions of the Perfectionist Overcontroller, Eating Disordered Overcontroller and Detached Self-Soother modes were noted, and new features were identified. The Perfectionist Overcontroller and Eating Disordered Overcontroller have been presented here as complex composite modes with sub-modes that work together in a coherent way in the service of the same project (Edwards, 2020b). Twenty-three features are identified in the parent modes. Blended parent modes, with multiple features active in a situation, were described. The blended parent modes expand on the existing literature on parent modes. The findings in this research support and extend the mode structure identified in the schema therapy theory, and highlight the idiosyncratic nature of the modes. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2021
- Full Text:
- Date Issued: 2021-10-29
Schema therapy for anorexia nervosa: an intensive systematic individual case study
- Authors: Alexander, Graham
- Date: 2021-10-29
- Subjects: Eating disorders , Anorexia nervosa , Anorexia nervosa Treatment , Anorexia nervosa Case studies , Schema-focused cognitive therapy , Anorexic overcontroller , Interpretative phenomenological analysis (IPA)
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/196082 , vital:45724 , DOI https://doi.org/10.21504/10962/196082
- Description: Developed more than three decades ago, schema therapy (ST) was born out of a need for a more effective way of working with difficult and challenging cases where patients were clearly unresponsive to the existing short-term cognitive therapies. While anchored in the primary theoretical orientation of cognitive therapy, ST has carefully integrated techniques and principles from attachment and object-relations therapies, as well as humanistic, gestalt and experiential therapies. The mode model emphasises the concept of “multiplicity” in terms of which the self is functionally divided into parts or schema modes. For a little more than a decade there has been growing interest amongst researcher-clinicians in the application of ST for the treatment of eating disorders (EDs) (Waller, et al., 2007; Simpson, 2012; Edwards, 2015; Munro et al., 2016; Simpson, 2016; Munro et al., 2016). While multivariate studies can provide quantifiable evidence for the efficacy of ST for treating EDs, systematic case-based research offers a means of engaging in an intensive analysis and description of the complex and subtle processes that unfold over time in a real-life therapeutic environment (Edwards et al., 2004; Yin, 1994). This research method also provides an opportunity for the refining of the clinical treatment model as well as its testing. Ten participants were assessed and treated with schema therapy. However, because of the large amount of data gathered, a decision was made to write up only one as an intensive systematic individual case study. Alison, an elderly woman with a longstanding history of AN who had been largely unresponsive to considerable previous therapies, received 100 ST sessions over a two-year period and showed a very positive response. The many challenges that arose and the way these were addressed within the ST framework provide an in-depth account of the application of the ST mode model for the treatment of AN. This is presented in a detailed therapy narrative. After results of the quantitative measures are provided, the next three chapters address three interpretative questions pertaining to the Healthy Adult/Vulnerable Child dyadic relationship, the processes of working with the Angry Child mode, and the conceptualising of an AN-specific coping mode. Several conclusions are drawn about the strengths of the schema therapy model and its particular application to AN. Amongst these is the importance of having a comprehensive case conceptualisation that serves as a collaborative “road map” with which to negotiate the unfolding collaborative therapeutic process. Another is the identifying of the “Anorexic Overcontroller” as a stand-alone coping mode that clarifies the functions of AN to hinder schema-based emotional injury, but paradoxically, still denies the individual’s basic core needs being met. Such a conceptualisation significantly assisted in the suspension of anorexic behaviour. A further significant observation is how emotion-focused work (especially within the context of chair work and imagery) brought therapy to life and was particularly effective in mobilising the conflict between internal voices. Another outstanding feature is how the building of a strong Healthy Adult mode proved vital in the healing process and the development of patient autonomy. Finally, therapy revealed how central the establishment of a sturdy, warm and loving therapeutic relationship is, and how influential the resonance between the therapist and patient is in the outcome of treatment. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Alexander, Graham
- Date: 2021-10-29
- Subjects: Eating disorders , Anorexia nervosa , Anorexia nervosa Treatment , Anorexia nervosa Case studies , Schema-focused cognitive therapy , Anorexic overcontroller , Interpretative phenomenological analysis (IPA)
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/196082 , vital:45724 , DOI https://doi.org/10.21504/10962/196082
- Description: Developed more than three decades ago, schema therapy (ST) was born out of a need for a more effective way of working with difficult and challenging cases where patients were clearly unresponsive to the existing short-term cognitive therapies. While anchored in the primary theoretical orientation of cognitive therapy, ST has carefully integrated techniques and principles from attachment and object-relations therapies, as well as humanistic, gestalt and experiential therapies. The mode model emphasises the concept of “multiplicity” in terms of which the self is functionally divided into parts or schema modes. For a little more than a decade there has been growing interest amongst researcher-clinicians in the application of ST for the treatment of eating disorders (EDs) (Waller, et al., 2007; Simpson, 2012; Edwards, 2015; Munro et al., 2016; Simpson, 2016; Munro et al., 2016). While multivariate studies can provide quantifiable evidence for the efficacy of ST for treating EDs, systematic case-based research offers a means of engaging in an intensive analysis and description of the complex and subtle processes that unfold over time in a real-life therapeutic environment (Edwards et al., 2004; Yin, 1994). This research method also provides an opportunity for the refining of the clinical treatment model as well as its testing. Ten participants were assessed and treated with schema therapy. However, because of the large amount of data gathered, a decision was made to write up only one as an intensive systematic individual case study. Alison, an elderly woman with a longstanding history of AN who had been largely unresponsive to considerable previous therapies, received 100 ST sessions over a two-year period and showed a very positive response. The many challenges that arose and the way these were addressed within the ST framework provide an in-depth account of the application of the ST mode model for the treatment of AN. This is presented in a detailed therapy narrative. After results of the quantitative measures are provided, the next three chapters address three interpretative questions pertaining to the Healthy Adult/Vulnerable Child dyadic relationship, the processes of working with the Angry Child mode, and the conceptualising of an AN-specific coping mode. Several conclusions are drawn about the strengths of the schema therapy model and its particular application to AN. Amongst these is the importance of having a comprehensive case conceptualisation that serves as a collaborative “road map” with which to negotiate the unfolding collaborative therapeutic process. Another is the identifying of the “Anorexic Overcontroller” as a stand-alone coping mode that clarifies the functions of AN to hinder schema-based emotional injury, but paradoxically, still denies the individual’s basic core needs being met. Such a conceptualisation significantly assisted in the suspension of anorexic behaviour. A further significant observation is how emotion-focused work (especially within the context of chair work and imagery) brought therapy to life and was particularly effective in mobilising the conflict between internal voices. Another outstanding feature is how the building of a strong Healthy Adult mode proved vital in the healing process and the development of patient autonomy. Finally, therapy revealed how central the establishment of a sturdy, warm and loving therapeutic relationship is, and how influential the resonance between the therapist and patient is in the outcome of treatment. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2021
- Full Text:
- Date Issued: 2021-10-29
Settlement and metamorphosis in the veliger larvae of the South African abalone Haliotis midae exposed to ambient grown biofilms treated with conspecific mucous
- Authors: Van Staden, Jefferson Luke
- Date: 2021-10-29
- Subjects: Haliotis midae , Biofilms , Haliotis midae Larvae Behavior , Haliotis midae Metamorphosis , Biosecurity , Aquaculture , Metamorphosis , Attachment mechanisms (Biology) , Mucous
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192187 , vital:45203
- Description: The South African abalone, Haliotis midae, is a commercially important species of mollusc which contributes significantly to the value of the South African mariculture industry. One of the primary challenges experienced by abalone farmers is the consistent production of juvenile abalone (spat) in sufficient volumes to keep stocking farms and facilitate expansion of the industry. One of the key production bottlenecks of H. midae is achieving adequate levels of larval attachment and metamorphosis (settlement). The larvae of H. midae are settled on polycarbonate plates which have been pre-conditioned with biofilms in seawater which is pumped ashore onto farms. The seasonal variability in settlement success reported by hatchery managers in South Africa is hypothesised to be as a result of different diatom species compositions colonising the settlement plates at different times of the year, with settlement success being lowest during the winter months. The following study investigated whether the addition of conspecific mucous to biofilms could result in elevated settlement success, and whether there was potential for sterilisation of this mucous. A novel method of mucous application, spraying it onto the plates as opposed to pre-grazing, was tested in settlement assays and the trials revealed the following results: • The addition of H. midae mucous induced significantly more larvae to attach to settlement plates, when mucous was harvested around the spawning season. • Elevated attachment of larvae on mucous treated plates did not result in more post-larvae occupying the plates at the end of trials, and increased mortality is likely attributed to introduction of pathogens in conjunction with mucous. • No increase in the final proportion of settled larvae which had metamorphosed or the rate at which they metamorphosed was observed between mucous application treatments and biofilm only treatments. Subsequent trials assessed whether methods of mucous handling could reduce the biosecurity risk associated with mucous use, and so mucous was either UV irradiated or autoclaved. These trials revealed the following findings: • No difference in attachment was seen between any treatments, including the untreated mucous. This is contrary to the findings of our initial experiments and illustrates that the attachment-inducing properties within mucous may be seasonally expressed. ii • Numbers of observed larvae/post-larvae on plates applied with UV and autoclaved mucous where less stable than biofilms only, especially in the second trial, illustrating that mucous still presents a biosecurity risk even after undergoing these handling methods as it may act as a substrate on which pathogenic bacteria could colonise. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Van Staden, Jefferson Luke
- Date: 2021-10-29
- Subjects: Haliotis midae , Biofilms , Haliotis midae Larvae Behavior , Haliotis midae Metamorphosis , Biosecurity , Aquaculture , Metamorphosis , Attachment mechanisms (Biology) , Mucous
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192187 , vital:45203
- Description: The South African abalone, Haliotis midae, is a commercially important species of mollusc which contributes significantly to the value of the South African mariculture industry. One of the primary challenges experienced by abalone farmers is the consistent production of juvenile abalone (spat) in sufficient volumes to keep stocking farms and facilitate expansion of the industry. One of the key production bottlenecks of H. midae is achieving adequate levels of larval attachment and metamorphosis (settlement). The larvae of H. midae are settled on polycarbonate plates which have been pre-conditioned with biofilms in seawater which is pumped ashore onto farms. The seasonal variability in settlement success reported by hatchery managers in South Africa is hypothesised to be as a result of different diatom species compositions colonising the settlement plates at different times of the year, with settlement success being lowest during the winter months. The following study investigated whether the addition of conspecific mucous to biofilms could result in elevated settlement success, and whether there was potential for sterilisation of this mucous. A novel method of mucous application, spraying it onto the plates as opposed to pre-grazing, was tested in settlement assays and the trials revealed the following results: • The addition of H. midae mucous induced significantly more larvae to attach to settlement plates, when mucous was harvested around the spawning season. • Elevated attachment of larvae on mucous treated plates did not result in more post-larvae occupying the plates at the end of trials, and increased mortality is likely attributed to introduction of pathogens in conjunction with mucous. • No increase in the final proportion of settled larvae which had metamorphosed or the rate at which they metamorphosed was observed between mucous application treatments and biofilm only treatments. Subsequent trials assessed whether methods of mucous handling could reduce the biosecurity risk associated with mucous use, and so mucous was either UV irradiated or autoclaved. These trials revealed the following findings: • No difference in attachment was seen between any treatments, including the untreated mucous. This is contrary to the findings of our initial experiments and illustrates that the attachment-inducing properties within mucous may be seasonally expressed. ii • Numbers of observed larvae/post-larvae on plates applied with UV and autoclaved mucous where less stable than biofilms only, especially in the second trial, illustrating that mucous still presents a biosecurity risk even after undergoing these handling methods as it may act as a substrate on which pathogenic bacteria could colonise. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2021
- Full Text:
- Date Issued: 2021-10-29
Shifting Norms and Practices of International Criminal Justice: Exploring African State and Non-State Agency at the International Criminal Court
- Authors: Mtero, Shingirai
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192875 , vital:45273
- Description: Thesis (PhD) -- Faculty of Humanities, Political and International Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Mtero, Shingirai
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192875 , vital:45273
- Description: Thesis (PhD) -- Faculty of Humanities, Political and International Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
Simulating the economic impact emerging from the strategic decision-making of firms: A macroeconomic agent-based model
- Giovannoni, Amalio Dino John
- Authors: Giovannoni, Amalio Dino John
- Date: 2021-10-29
- Subjects: Decision making Economic aspects , Industrial management Decision making , Industrial management Computer simulation , Knowledge economy , Technological unemployment , Economic development Computer simulation , Employees Training of
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191887 , vital:45175
- Description: The key research problem addressed in this project is: how does the strategic decision making of firms affect an economy? While this is a difficult question to answer, insights may be gained through the use of computational techniques such as agent-based modelling (ABM). An agent-based model is developed that simulates micro-level economic interactions between individuals and _rms in different markets, resulting in emergent macro-level features. Technological progress is an important determinant of economic growth and has been decomposed into two complementary factors: knowledge and technological sophistication. The model is used to explore the long-term, macroeconomic consequences of _rms investing more heavily in knowledge development. The simulations show that a shift towards a knowledge-based economy (KBE) has an insignificant impact on GDP over the long-term. However, the shift does produce a significant increase in unemployment. The higher unemployment is shown to be particularly high for the unskilled sectors of the population. It is therefore paramount that companies embark on skills development, training and educational initiatives when following a path of technological and knowledge innovation. A transformation of the education system to one that is inclusive, focused on quality, adaptive, encourages creativity, aligned with the needs of industry, and stimulates R&D is crucial. Without a coordinated strategy between industry, academia, and government in attempts to achieve a KBE, economic growth may be constrained, while the levels of unemployment, inequality and poverty may deteriorate. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Giovannoni, Amalio Dino John
- Date: 2021-10-29
- Subjects: Decision making Economic aspects , Industrial management Decision making , Industrial management Computer simulation , Knowledge economy , Technological unemployment , Economic development Computer simulation , Employees Training of
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191887 , vital:45175
- Description: The key research problem addressed in this project is: how does the strategic decision making of firms affect an economy? While this is a difficult question to answer, insights may be gained through the use of computational techniques such as agent-based modelling (ABM). An agent-based model is developed that simulates micro-level economic interactions between individuals and _rms in different markets, resulting in emergent macro-level features. Technological progress is an important determinant of economic growth and has been decomposed into two complementary factors: knowledge and technological sophistication. The model is used to explore the long-term, macroeconomic consequences of _rms investing more heavily in knowledge development. The simulations show that a shift towards a knowledge-based economy (KBE) has an insignificant impact on GDP over the long-term. However, the shift does produce a significant increase in unemployment. The higher unemployment is shown to be particularly high for the unskilled sectors of the population. It is therefore paramount that companies embark on skills development, training and educational initiatives when following a path of technological and knowledge innovation. A transformation of the education system to one that is inclusive, focused on quality, adaptive, encourages creativity, aligned with the needs of industry, and stimulates R&D is crucial. Without a coordinated strategy between industry, academia, and government in attempts to achieve a KBE, economic growth may be constrained, while the levels of unemployment, inequality and poverty may deteriorate. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2021
- Full Text:
- Date Issued: 2021-10-29
Spatial analysis of the impact of human activities on the marine environment in Algoa Bay, South Africa
- Authors: Maphoto, Tidimalo Mary Anne
- Date: 2021-10-29
- Subjects: Marine resources conservation Algoa Bay South Africa , Spatial analysis (Statistics) , Human ecology , Nature Effect of human beings on , Marine ecology Algoa Bay South Africa , Integrated coastal zone management Algoa Bay South Africa , Marine spatial planning Algoa Bay South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192086 , vital:45194
- Description: Background: Humans have a long history of using the marine environment in multiple ways and continued use has led to a decline in the ecosystem services provided by marine systems in many places. In addition, human activities have steadily increased with time and advances in technology, further increasing impacts on marine systems. To understand and manage these impacts, we need to assess the spatial distribution and intensity of human activities in the marine environment, and quantify, where possible, their cumulative impacts on marine ecosystems. The spatial consideration of human activities and their associated impacts is important for conservation planning, Integrated Ocean Management and Marine Spatial Planning (MSP) initiatives. The main deliverable of this research study was to develop a cumulative impacts layer of human activities in Algoa Bay, South Africa, to support the Algoa Bay Marine Spatial Planning Project. Objective and Relevance: This research analyses the spatial impacts of human activities on the Algoa Bay marine environment (excluding the seashore). Algoa Bay is located on the south coast of South Africa in the Eastern Cape. The research explores stakeholders' perceptions of their knowledge of the human activities that take place in the bay. This research is informed by an expert-based geographical information systems (GIS) approach and cumulative impact assessment in order to map the spatial impacts of the activities as part of marine spatial planning. "Experts" were defined as stakeholders that contributed valuable knowledge of the human activities and their impacts; this definition of expert included "professional" and "non-professional" contributors to knowledge. The spatial aspect of the research is a significant contribution to the field as it will help inform decision-making in the Algoa Bay Marine Spatial Planning Project. Design and Methods: A mixed-method approach was used to generate data. A snowball sampling approach was used to identify research participants from key informants. Primary data were collected through questionnaire surveys, interviews and a focus group. Secondary data sources consisted of GIS data and reports from scientific organizations. Findings and Conclusion: The research findings indicate that the top three pressures that cause the greatest impact on the Algoa Bay marine environment are fishing, pollution and shipping. The cumulative impact of these activities was highest near harbours in Algoa Bay. The marine ecosystems that were most impacted by pressures were the Agulhas Island and the Agulhas Mixed Shore. The Warm Temperate marine ecosystems had fairly low cumulative impacts. The research findings indicate that there is a complex mix of human activities that impact the marine environment. This research supports the findings of other researchers that reveal that the highest cumulative impact is in areas closer to the coast and harbours owing to high population densities. Value of Study: This study builds onto the existing data by expanding the knowledge base and including more stakeholders to integrate as many human activities as possible and bring a holistic picture of the ocean's uses to inform MSP in Algoa Bay. , Thesis (MSc) -- Faculty of Science, Geography, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Maphoto, Tidimalo Mary Anne
- Date: 2021-10-29
- Subjects: Marine resources conservation Algoa Bay South Africa , Spatial analysis (Statistics) , Human ecology , Nature Effect of human beings on , Marine ecology Algoa Bay South Africa , Integrated coastal zone management Algoa Bay South Africa , Marine spatial planning Algoa Bay South Africa
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192086 , vital:45194
- Description: Background: Humans have a long history of using the marine environment in multiple ways and continued use has led to a decline in the ecosystem services provided by marine systems in many places. In addition, human activities have steadily increased with time and advances in technology, further increasing impacts on marine systems. To understand and manage these impacts, we need to assess the spatial distribution and intensity of human activities in the marine environment, and quantify, where possible, their cumulative impacts on marine ecosystems. The spatial consideration of human activities and their associated impacts is important for conservation planning, Integrated Ocean Management and Marine Spatial Planning (MSP) initiatives. The main deliverable of this research study was to develop a cumulative impacts layer of human activities in Algoa Bay, South Africa, to support the Algoa Bay Marine Spatial Planning Project. Objective and Relevance: This research analyses the spatial impacts of human activities on the Algoa Bay marine environment (excluding the seashore). Algoa Bay is located on the south coast of South Africa in the Eastern Cape. The research explores stakeholders' perceptions of their knowledge of the human activities that take place in the bay. This research is informed by an expert-based geographical information systems (GIS) approach and cumulative impact assessment in order to map the spatial impacts of the activities as part of marine spatial planning. "Experts" were defined as stakeholders that contributed valuable knowledge of the human activities and their impacts; this definition of expert included "professional" and "non-professional" contributors to knowledge. The spatial aspect of the research is a significant contribution to the field as it will help inform decision-making in the Algoa Bay Marine Spatial Planning Project. Design and Methods: A mixed-method approach was used to generate data. A snowball sampling approach was used to identify research participants from key informants. Primary data were collected through questionnaire surveys, interviews and a focus group. Secondary data sources consisted of GIS data and reports from scientific organizations. Findings and Conclusion: The research findings indicate that the top three pressures that cause the greatest impact on the Algoa Bay marine environment are fishing, pollution and shipping. The cumulative impact of these activities was highest near harbours in Algoa Bay. The marine ecosystems that were most impacted by pressures were the Agulhas Island and the Agulhas Mixed Shore. The Warm Temperate marine ecosystems had fairly low cumulative impacts. The research findings indicate that there is a complex mix of human activities that impact the marine environment. This research supports the findings of other researchers that reveal that the highest cumulative impact is in areas closer to the coast and harbours owing to high population densities. Value of Study: This study builds onto the existing data by expanding the knowledge base and including more stakeholders to integrate as many human activities as possible and bring a holistic picture of the ocean's uses to inform MSP in Algoa Bay. , Thesis (MSc) -- Faculty of Science, Geography, 2021
- Full Text:
- Date Issued: 2021-10-29
Stable Covalent pH-Sensitive Metallophthalocyanines Thin Monolayer Films for Selective Detection of Neurotransmitters
- Idowu, Abosede Omowumi Atinuke
- Authors: Idowu, Abosede Omowumi Atinuke
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192922 , vital:45279
- Description: Thesis (PhD) -- Faculty of Humanities, Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Idowu, Abosede Omowumi Atinuke
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192922 , vital:45279
- Description: Thesis (PhD) -- Faculty of Humanities, Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10-29
Sustainability focus in water management and curriculum practices in an agricultural college: a case study of Fort Cox Agriculture and Forestry Training Institute
- Authors: Ramphinwa, Azwindini Edson
- Date: 2021-10-29
- Subjects: Water-supply Management South Africa Ixesi , Water-supply Management Study and teaching (Higher) South Africa Ixesi , Curriculum planning South Africa Ixesi , Environmental education Activity programs South Africa Ixesi , Agricultural colleges Curricula South Africa Ixesi , Sustainable development South Africa Ixesi , Educational change South Africa , Fort Cox Agriculture and Forestry Training Institute , Practice Architectures Theory (PAT)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192030 , vital:45189
- Description: This case study of Fort Cox Agriculture and Forestry Training Institute explored the sustainability focus in water management and curriculum practices. I was inspired to develop a deeper understanding of current water management and curriculum practices at Fort Cox with fellow academics involved in the teaching of water dependent curricula, students who were enrolled in water dependent subjects, and support staff involved in water management practices around campus. My initial assumption was there was a practice disconnect or mismatch between water management practices and the stated curriculum requirements at Fort Cox. To develop a deeper understanding and possible responses, the study adopted the Practice Architectures Theory (PAT) developed by Kemmis (2009) and Kemmis, McTaggart and Nixon (2013). A supportive theory was also considered in the form of the action learning process developed by Marquardt (2007), which was aimed at bringing people together in an attempt to respond to water management practice concerns in their context. Practice Architectures Theory was used with the view to understand the ‘sayings, doings, and relatings’ regarding water management and curriculum practices at Fort Cox, in particular around Irrigation, Soil and Water Conservation subjects and the other water dependent subjects. Kemmis et al. (2013) suggested that practices come into being because people do not act alone but as a collective, and bring them into being. In practice, individual understanding and action are orchestrated in collective social-relational projects. A qualitative case study approach was used to solicit data using different techniques namely workshops, semi-structured interviews, document analysis, observations and Unit-Based Sustainability Assessment Tool questionnaires. Data collected through all these techniques was triangulated in the form of analytical memoranda which helped to develop analytical statements aligned with the research goals. The findings confirmed the evident practice disconnect between water management and curriculum practices which was found to be problematic at Fort Cox. The findings also suggest that there were inadequate water management topics across the curriculum. The findings lead to recommendations including future research recommendations for possible implementation. One notable recommendation is staff development on current sustainable water management and curriculum practices to address the challenges of both Fort Cox and the region. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Ramphinwa, Azwindini Edson
- Date: 2021-10-29
- Subjects: Water-supply Management South Africa Ixesi , Water-supply Management Study and teaching (Higher) South Africa Ixesi , Curriculum planning South Africa Ixesi , Environmental education Activity programs South Africa Ixesi , Agricultural colleges Curricula South Africa Ixesi , Sustainable development South Africa Ixesi , Educational change South Africa , Fort Cox Agriculture and Forestry Training Institute , Practice Architectures Theory (PAT)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192030 , vital:45189
- Description: This case study of Fort Cox Agriculture and Forestry Training Institute explored the sustainability focus in water management and curriculum practices. I was inspired to develop a deeper understanding of current water management and curriculum practices at Fort Cox with fellow academics involved in the teaching of water dependent curricula, students who were enrolled in water dependent subjects, and support staff involved in water management practices around campus. My initial assumption was there was a practice disconnect or mismatch between water management practices and the stated curriculum requirements at Fort Cox. To develop a deeper understanding and possible responses, the study adopted the Practice Architectures Theory (PAT) developed by Kemmis (2009) and Kemmis, McTaggart and Nixon (2013). A supportive theory was also considered in the form of the action learning process developed by Marquardt (2007), which was aimed at bringing people together in an attempt to respond to water management practice concerns in their context. Practice Architectures Theory was used with the view to understand the ‘sayings, doings, and relatings’ regarding water management and curriculum practices at Fort Cox, in particular around Irrigation, Soil and Water Conservation subjects and the other water dependent subjects. Kemmis et al. (2013) suggested that practices come into being because people do not act alone but as a collective, and bring them into being. In practice, individual understanding and action are orchestrated in collective social-relational projects. A qualitative case study approach was used to solicit data using different techniques namely workshops, semi-structured interviews, document analysis, observations and Unit-Based Sustainability Assessment Tool questionnaires. Data collected through all these techniques was triangulated in the form of analytical memoranda which helped to develop analytical statements aligned with the research goals. The findings confirmed the evident practice disconnect between water management and curriculum practices which was found to be problematic at Fort Cox. The findings also suggest that there were inadequate water management topics across the curriculum. The findings lead to recommendations including future research recommendations for possible implementation. One notable recommendation is staff development on current sustainable water management and curriculum practices to address the challenges of both Fort Cox and the region. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-10-29
Synthesis and antiparasitic activity of hybrid compounds based on quinoline and thiosemicarbazone pharmacophoric units
- Authors: Makalima, Gwiba Hlonela
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192508 , vital:45232
- Description: Thesis (MSc) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Makalima, Gwiba Hlonela
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192508 , vital:45232
- Description: Thesis (MSc) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10-29
Synthesis, characterization and antiparasitic evaluation of chalcone hybrids
- Authors: Zulu, Ayanda Ignatia
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192853 , vital:45271
- Description: Thesis (PhD) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Zulu, Ayanda Ignatia
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192853 , vital:45271
- Description: Thesis (PhD) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10-29
Systematics of the Afrotropical Chalcididae (Hymenoptera: Chalcidoidea)
- Authors: Faure, Sariana
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192808 , vital:45266
- Description: Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Faure, Sariana
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192808 , vital:45266
- Description: Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-10-29
Taxonomic, ecological and biogeographic re-evaluation of temperate stream fishes in Southern Africa: a case study of the enteromius anoplus complex
- Authors: Kambikambi, Manda Juliet
- Date: 2021-10-29
- Subjects: Stream ecology South Africa , Barbs (Fish) Ecology South Africa Cape Fold Belt , Barbs (Fish) Ecology South Africa Highveld (Region) , Barbs (Fish) Ecology South Africa Amathole District Municipality , Biotic communities South Africa , Fishes Classification , Cryptic species , Chubbyhead barb
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/191023 , vital:45051 , 10.21504/10962/191023
- Description: Worldwide, cryptic species, which comprise two or more distinct species that are classified as one due to their morphological similarity, are more common than previously thought. In South Africa, the chubbyhead barb, Enteromius anoplus (Weber, 1897), is the most widespread freshwater fish species. The widespread occurrence of this species across different river basins raised questions on its taxonomic status due to the likely occurrence of hidden diversity. This further raised the need to evaluate the ecological patterns associated with likely occurrence of such hidden diversity. Phylogenetic analyses of the cytochrome b gene of E. anoplus populations across South Africa revealed the occurrence of four genetically distinct species. These findings supported the restoration Enteromius cernuus (Barnard 1943) stat. rev. from the Olifants River system; the restoration of Enteromius anoplus sensu stricto (Weber 1897) stat. rev. from the Gouritz River system; the redescription of Enteromius oraniensis (Barnard 1943) stat. rev. from the Orange River system; and the description of a new species, Enteromius mandelai sp. nov. from the Eastern Cape rivers. Analyses of morphometric and meristic data revealed that these species were differentiated based on barbel length and number of lateral line scales. Ecological studies on Enteromius mandelai were conducted within headwater streams of major river systems in the Eastern Cape region. These headwater streams had different catchment characteristics ranging from near-natural to anthropogenically-perturbed mainly due to agriculture-related disturbances and invasion of riparian zones by non-native plants. Stable isotope analysis provided evidence of trophic plasticity for E. mandelai across the different headwater streams. Specifically, E. mandelai exhibited large isotopic niches in agriculture-disturbed headwater streams, whereas small isotopic niches were observed in headwater streams invaded by non-native plants. Because of the evidence of trophic plasticity for E. mandelai, this study further hypothesized that this species would exhibit variable environmental niche patterns related to its distribution, abundance and the presence of contra-specifics due to different abiotic factors across its range. Enteromius mandelai was generally most abundant at sites with high total dissolved solids and sand substratum, which was characteristic of large pool habitats, and least abundant at sites with high turbidity. In the Great Fish River, E. mandelai occurred as the only species in most headwater sites, whereas in the Keiskamma and Buffalo River systems, it co-occurred with Amatolacypris trevelyani and Sandelia bainsii. Enteromius mandelai was, nevertheless, found to be ubiquitous together with having wide environmental niches, and exhibited no discernible patterns in its habitat associations. The taxonomic re-evaluation of the E. anoplus complex, which provided evidence of the existence of new species, has implications for the biogeographic zonation of the ichthyofauna of the Cape Fold Ecoregion (CFE), Amathole-Winterberg Highlands Ecoregion (AWHE) and the Southern Temperate Highveld Ecoregion (STHE). For example, the currently recognised southern limit of the STHE, which encompasses the AWHE, is based on the occurrence of E. anoplus, Enteromius pallidus and Labeo umbratus. However, evidence from this and other recent studies indicate the occurrence of either new species or distinct lineages in the southern-most section of the STHE, which is consistent with the patterns observed in the CFE. Comparison of taxonomic composition showed that species in the eastern part of the CFE were similar to species in the AWHE and the southern-most section of the STHE. Because of the close affinities among most of the new taxa in these regions, this study proposes that the current delimitation of the CFE should be reviewed by extending it to include the AWHE and sections of the STHE. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Kambikambi, Manda Juliet
- Date: 2021-10-29
- Subjects: Stream ecology South Africa , Barbs (Fish) Ecology South Africa Cape Fold Belt , Barbs (Fish) Ecology South Africa Highveld (Region) , Barbs (Fish) Ecology South Africa Amathole District Municipality , Biotic communities South Africa , Fishes Classification , Cryptic species , Chubbyhead barb
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/191023 , vital:45051 , 10.21504/10962/191023
- Description: Worldwide, cryptic species, which comprise two or more distinct species that are classified as one due to their morphological similarity, are more common than previously thought. In South Africa, the chubbyhead barb, Enteromius anoplus (Weber, 1897), is the most widespread freshwater fish species. The widespread occurrence of this species across different river basins raised questions on its taxonomic status due to the likely occurrence of hidden diversity. This further raised the need to evaluate the ecological patterns associated with likely occurrence of such hidden diversity. Phylogenetic analyses of the cytochrome b gene of E. anoplus populations across South Africa revealed the occurrence of four genetically distinct species. These findings supported the restoration Enteromius cernuus (Barnard 1943) stat. rev. from the Olifants River system; the restoration of Enteromius anoplus sensu stricto (Weber 1897) stat. rev. from the Gouritz River system; the redescription of Enteromius oraniensis (Barnard 1943) stat. rev. from the Orange River system; and the description of a new species, Enteromius mandelai sp. nov. from the Eastern Cape rivers. Analyses of morphometric and meristic data revealed that these species were differentiated based on barbel length and number of lateral line scales. Ecological studies on Enteromius mandelai were conducted within headwater streams of major river systems in the Eastern Cape region. These headwater streams had different catchment characteristics ranging from near-natural to anthropogenically-perturbed mainly due to agriculture-related disturbances and invasion of riparian zones by non-native plants. Stable isotope analysis provided evidence of trophic plasticity for E. mandelai across the different headwater streams. Specifically, E. mandelai exhibited large isotopic niches in agriculture-disturbed headwater streams, whereas small isotopic niches were observed in headwater streams invaded by non-native plants. Because of the evidence of trophic plasticity for E. mandelai, this study further hypothesized that this species would exhibit variable environmental niche patterns related to its distribution, abundance and the presence of contra-specifics due to different abiotic factors across its range. Enteromius mandelai was generally most abundant at sites with high total dissolved solids and sand substratum, which was characteristic of large pool habitats, and least abundant at sites with high turbidity. In the Great Fish River, E. mandelai occurred as the only species in most headwater sites, whereas in the Keiskamma and Buffalo River systems, it co-occurred with Amatolacypris trevelyani and Sandelia bainsii. Enteromius mandelai was, nevertheless, found to be ubiquitous together with having wide environmental niches, and exhibited no discernible patterns in its habitat associations. The taxonomic re-evaluation of the E. anoplus complex, which provided evidence of the existence of new species, has implications for the biogeographic zonation of the ichthyofauna of the Cape Fold Ecoregion (CFE), Amathole-Winterberg Highlands Ecoregion (AWHE) and the Southern Temperate Highveld Ecoregion (STHE). For example, the currently recognised southern limit of the STHE, which encompasses the AWHE, is based on the occurrence of E. anoplus, Enteromius pallidus and Labeo umbratus. However, evidence from this and other recent studies indicate the occurrence of either new species or distinct lineages in the southern-most section of the STHE, which is consistent with the patterns observed in the CFE. Comparison of taxonomic composition showed that species in the eastern part of the CFE were similar to species in the AWHE and the southern-most section of the STHE. Because of the close affinities among most of the new taxa in these regions, this study proposes that the current delimitation of the CFE should be reviewed by extending it to include the AWHE and sections of the STHE. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2021
- Full Text:
- Date Issued: 2021-10-29
Tense and aspect in Xhosa
- Authors: Savić, Stefan
- Date: 2021-10-29
- Subjects: Xhosa language , Xhosa language Grammar , Xhosa language Semantics , Xhosa language Tense , Xhosa language Aspect , Xhosa language Syntax , Xhosa language Morphology , Xhosa language Grammar, Comparative , Information structure
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192897 , vital:45277 , 10.21504/10962/192897
- Description: This dissertation investigates the semantics of each tense and aspect in Xhosa. Since tense and aspect perform important pragmatic functions, the analysis takes into account the correlation between the verb and the wider discourse in which it is embedded. Tense reflects the temporal relation between the time of the utterance (speech time) and an interval the speaker makes the assertion about (reference time). The Remote Past and the Remote Future tenses differ from their Recent/Immediate counterparts in that they denote events which occurred in a significantly different situation than the speech time and/or events in the surrounding discourse. Aspect does not only indicate the relation between the time occupied by the real world event and the reference time chosen by the speaker. The Perfective aspect represents an event as a unique change-of-state that pertains to a single point on the timeline which at the same time functions as the reference time. By contrast, for the Imperfective aspect temporally links the event to a contextually provided reference time, e.g. the utterance time, a time adverbial, a period of time previously introduced in the preceding discourse, or the interlocutors’ shared experience. At the pragmatic level, the Perfective aspect tends to introduce an event’s resulting state into the discourse, whereas the Imperfective aspect tends to rule it out. Like the Imperfective aspect, the Anterior and the Prospective aspects assert an event’s occurrence from a contextually defined reference time. They refer to the consequent and the preparatory states of an event, respectively. On the pragmatic level, the Anterior aspect may also indicate that the truth-conditionality of the event’s resulting state is contradicted in the immediate discourse. This study shows that tense and aspect temporally represent different means of temporally assigning an event to a particular portion of the timeline. I further argue that aspect indicates whether the reference time is provided in the context (Imperfective, Anterior, Prospective) or whether it is introduced by the verb itself (Perfective). Furthermore, this study shows that aspect exhibits a pragmatic function by laying focus on different parts of the event that are relevant in the upcoming discourse. , Thesis (PhD) -- Faculty of Humanities, Linguistics and Applied Languages Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Savić, Stefan
- Date: 2021-10-29
- Subjects: Xhosa language , Xhosa language Grammar , Xhosa language Semantics , Xhosa language Tense , Xhosa language Aspect , Xhosa language Syntax , Xhosa language Morphology , Xhosa language Grammar, Comparative , Information structure
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192897 , vital:45277 , 10.21504/10962/192897
- Description: This dissertation investigates the semantics of each tense and aspect in Xhosa. Since tense and aspect perform important pragmatic functions, the analysis takes into account the correlation between the verb and the wider discourse in which it is embedded. Tense reflects the temporal relation between the time of the utterance (speech time) and an interval the speaker makes the assertion about (reference time). The Remote Past and the Remote Future tenses differ from their Recent/Immediate counterparts in that they denote events which occurred in a significantly different situation than the speech time and/or events in the surrounding discourse. Aspect does not only indicate the relation between the time occupied by the real world event and the reference time chosen by the speaker. The Perfective aspect represents an event as a unique change-of-state that pertains to a single point on the timeline which at the same time functions as the reference time. By contrast, for the Imperfective aspect temporally links the event to a contextually provided reference time, e.g. the utterance time, a time adverbial, a period of time previously introduced in the preceding discourse, or the interlocutors’ shared experience. At the pragmatic level, the Perfective aspect tends to introduce an event’s resulting state into the discourse, whereas the Imperfective aspect tends to rule it out. Like the Imperfective aspect, the Anterior and the Prospective aspects assert an event’s occurrence from a contextually defined reference time. They refer to the consequent and the preparatory states of an event, respectively. On the pragmatic level, the Anterior aspect may also indicate that the truth-conditionality of the event’s resulting state is contradicted in the immediate discourse. This study shows that tense and aspect temporally represent different means of temporally assigning an event to a particular portion of the timeline. I further argue that aspect indicates whether the reference time is provided in the context (Imperfective, Anterior, Prospective) or whether it is introduced by the verb itself (Perfective). Furthermore, this study shows that aspect exhibits a pragmatic function by laying focus on different parts of the event that are relevant in the upcoming discourse. , Thesis (PhD) -- Faculty of Humanities, Linguistics and Applied Languages Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
The bastards of Euripides: illegitimacy in the Hippolytus, the Andromache, and the Ion
- Sülter, James Nicholas Edwin
- Authors: Sülter, James Nicholas Edwin
- Date: 2021-10-29
- Subjects: Euripides , Euripides Criticism and interpretation , Euripides. Hippolytus , Euripides. Andromache , Euripides. Ion , Illegitimacy in literature , Tragedy History and criticism , Citizenship in literature
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190030 , vital:44957
- Description: The Pericles Citizenship Law of 451 made citizenship contingent on an individual man having Athenian blood on both his father and mother’s side. Men with foreign mothers were denied any rights to the key institutions that conferred Athenian belonging, such as deme and phratry membership, as well as, of course, citizenship. When, however, the Peloponnesian War began in 431, the population of Athenian citizens was quickly diminished by military conflict and plague and they sought a solution to repopulate their numbers with as little change to the original law as possible. The result was an amendment in 429 allowing citizens with no living legitimate (γνήσιοι) heirs to legitimise their bastards (νόθοι) in their place. A year after this, Euripides wrote the Hippolytus, a play that deals very closely with the issues of bastardy, bastards’ place in the polis and the oikos, and their treatment by those who are legitimate. As the war went on, he proceeded to produce two other plays containing bastard characters, the Andromache (c.425) and the Ion (c.413), in which he similarly explored the consequences of illegitimacy. In all three plays his attitude towards bastards is overwhelmingly sympathetic and the way he chooses to present their situations suggests his disagreement with the arrogance and antipathy that continued to push many of these often very worthy individuals to the fringes of society. This thesis seeks to examine Euripides’ presentation of bastards through a close reading of the relevant texts, in order to understand how the plays reacted to the contemporary circumstances of and what comments they are making. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Sülter, James Nicholas Edwin
- Date: 2021-10-29
- Subjects: Euripides , Euripides Criticism and interpretation , Euripides. Hippolytus , Euripides. Andromache , Euripides. Ion , Illegitimacy in literature , Tragedy History and criticism , Citizenship in literature
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190030 , vital:44957
- Description: The Pericles Citizenship Law of 451 made citizenship contingent on an individual man having Athenian blood on both his father and mother’s side. Men with foreign mothers were denied any rights to the key institutions that conferred Athenian belonging, such as deme and phratry membership, as well as, of course, citizenship. When, however, the Peloponnesian War began in 431, the population of Athenian citizens was quickly diminished by military conflict and plague and they sought a solution to repopulate their numbers with as little change to the original law as possible. The result was an amendment in 429 allowing citizens with no living legitimate (γνήσιοι) heirs to legitimise their bastards (νόθοι) in their place. A year after this, Euripides wrote the Hippolytus, a play that deals very closely with the issues of bastardy, bastards’ place in the polis and the oikos, and their treatment by those who are legitimate. As the war went on, he proceeded to produce two other plays containing bastard characters, the Andromache (c.425) and the Ion (c.413), in which he similarly explored the consequences of illegitimacy. In all three plays his attitude towards bastards is overwhelmingly sympathetic and the way he chooses to present their situations suggests his disagreement with the arrogance and antipathy that continued to push many of these often very worthy individuals to the fringes of society. This thesis seeks to examine Euripides’ presentation of bastards through a close reading of the relevant texts, in order to understand how the plays reacted to the contemporary circumstances of and what comments they are making. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-10-29
The biological control of Egeria densa Planch. (Hydrocharitaceae) in South Africa
- Authors: Smith, Rosali
- Date: 2021-10-29
- Subjects: Egeria (Plant genus) Biological control South Africa , Hydrocharitaceae Biological control South Africa , Aquatic weeds Biological control South Africa , Leafminers South Africa , Plant invasions South Africa , Resilience (Ecology) South Africa , Freshwater ecology South Africa , Hydrellia South Africa , Submerged macrophyte
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/191102 , vital:45060 , 10.21504/10962/191102
- Description: Over the last thirty years, biological control, the use of host-specific natural enemies, has been a huge asset in the management exotic aquatic macrophytes such as Pistia stratiotes L. (Araceae), Pontederia crassipes Mart. (Solms) (Pontederiaceae), Azolla filiculoides Lam. (Azollaceae), Salvinia molesta D.S. Mitch (Salviniaceae) and Myriophyllum aquaticum (Vell.) Verdc. (Haloragaceae), also known as the “Big Bad Five” in South Africa. Despite these successes, freshwater ecosystems in South Africa have been harder to restore to an invasive macrophyte-free space, due to chronic disturbances such eutrophication, propagule dispersal and hydrological alterations. In the Anthropocene, where human activities have profound effects on their environment, these disturbances weakens ecological resilience and drive aquatic plant invasions. Due to long periods of invasions and the presence of a new suite of exotic aquatic plant propagules, native vegetation recolonization has been slow or even absent. Instead, the release of resources, such as sunlight, nutrient and space through aquatic weed management acts as a catalyst for secondary biological invasion. New invasive aquatic weeds include submerged and rooted emergent growth types, with Egeria densa Planch. (Hydrocharitaceae) the most widely distributed submerged aquatic weed in South Africa. It can quickly form dense monoculture stands that have ecological, economic and social impacts. Because of its ability to regenerate from plant fragments with double nodes, mechanical control is inappropriate. Additionally, mechanical and chemical control not only affects E. densa but have significant non-target effects. In response to its rapid spread over the last 20 years, especially following floating invasive aquatic management, a biological control programme was initiated, and in 2018, the leaf-mining fly, Hydrellia egeriae Rodrigues (Diptera: Ephydridae) was released. This was the first release of a biological control agent against E. densa in the world, and the first agent released against a submerged aquatic weed in South Africa. This thesis comprises the subsequent step of a biological control program when permission for the release of an agent have been obtained. A brief history of macrophyte invasions in South Africa’s unique freshwater systems are given in the literature review. Contributing factors to secondary invasions within the context of ecological resilience are introduced. An argument for the benefit of biological control as nuisance control is given, especially because E. densa and its natural enemy, H. egeriae is the focus species of this thesis. The main goal after permission for the release of an agent have been obtained, is to establish and build-up field populations. Research questions in this thesis aimed to investigate factors that contribute to or negate this goal. Through laboratory and field experiments we investigated the thermal physiology of the agent, and its climatic suitability to its novel range; different release strategies on field establishment and biotic resistance through the acquisition of novel parasitoids. Considering the longevity of this biological control program, we investigated the effects of elevated CO2 on the interaction between E. densa and H. egeriae through open top chamber experiments. Laboratory thermal physiology results showed that the agent is able to survive, develop and proliferate at all E. densa sites throughout the year. This is confirmed with the establishment of the agent at two release sites, the Nahoon River in the Eastern Cape Province and the Midmar Dam in KwaZulu-Natal. Post-release surveys showed that H. egeriae requires augmentative releases to sustain field populations. Without augmentative releases, H. egeriae herbivory levels were almost negligent. However, a contributing factor to low field-populations was parasitism. The biological control agent acquired three parasitoids, which have previously been described from Hydrellia lagarosiphon Deeming (Diptera: Ephydridae), a specific herbivore to Lagarosiphon major (Ridl.) Moss (Hydrocharitaceae). These results provide information on the immediate establishment and effectiveness of the H. egeriae. Results from the elevated CO2 study suggest that E. densa will become less nutritious through a shift in leaf C/N ratio, when ambient 800ppm is bubbled into experimental growth chambers. Hydrellia egeriae feeding was affected by ambient CO2 levels and plant nutrient availability. The set levels of ambient CO2 levels used in this experiment produced dissolved inorganic carbon levels that were lower than dissolved inorganic carbon levels in E. densa invaded sites. This suggests that, submerged aquatic plant-insect interactions may be harder to predict from only laboratory experiments. Further investigations are necessary to establish system-specific characteristics i.e. dissolved inorganic carbon and target plant nutritional quality. The biological control of E. densa in South Africa is still in its infancy. This study presents results from post-release surveys up until two years after the agent was released. From this study, Hydrellia egeriae exhibits the potential to be an effective biological control agent, but release strategies should be adapted to sustain field populations and to limit field parasitism effects. Continued post-release surveys will provide a more comprehensive idea of the seasonal fluctuations of field-populations and parasitism. Surveys at multiple sites will provide information on potential site specific characteristics that contribute to or negate biological effort. Considering the high nutrient status of South African freshwater systems, a more holistic approach to E. densa management is necessary. This will require the strengthening of ecological resilience to prevent systems from shifting into an alternate invasive stable state. In addition, aquatic weed management needs to be addressed by a resilient social network, which ultimately calls for the strengthening of socio-ecological resilience. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Smith, Rosali
- Date: 2021-10-29
- Subjects: Egeria (Plant genus) Biological control South Africa , Hydrocharitaceae Biological control South Africa , Aquatic weeds Biological control South Africa , Leafminers South Africa , Plant invasions South Africa , Resilience (Ecology) South Africa , Freshwater ecology South Africa , Hydrellia South Africa , Submerged macrophyte
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/191102 , vital:45060 , 10.21504/10962/191102
- Description: Over the last thirty years, biological control, the use of host-specific natural enemies, has been a huge asset in the management exotic aquatic macrophytes such as Pistia stratiotes L. (Araceae), Pontederia crassipes Mart. (Solms) (Pontederiaceae), Azolla filiculoides Lam. (Azollaceae), Salvinia molesta D.S. Mitch (Salviniaceae) and Myriophyllum aquaticum (Vell.) Verdc. (Haloragaceae), also known as the “Big Bad Five” in South Africa. Despite these successes, freshwater ecosystems in South Africa have been harder to restore to an invasive macrophyte-free space, due to chronic disturbances such eutrophication, propagule dispersal and hydrological alterations. In the Anthropocene, where human activities have profound effects on their environment, these disturbances weakens ecological resilience and drive aquatic plant invasions. Due to long periods of invasions and the presence of a new suite of exotic aquatic plant propagules, native vegetation recolonization has been slow or even absent. Instead, the release of resources, such as sunlight, nutrient and space through aquatic weed management acts as a catalyst for secondary biological invasion. New invasive aquatic weeds include submerged and rooted emergent growth types, with Egeria densa Planch. (Hydrocharitaceae) the most widely distributed submerged aquatic weed in South Africa. It can quickly form dense monoculture stands that have ecological, economic and social impacts. Because of its ability to regenerate from plant fragments with double nodes, mechanical control is inappropriate. Additionally, mechanical and chemical control not only affects E. densa but have significant non-target effects. In response to its rapid spread over the last 20 years, especially following floating invasive aquatic management, a biological control programme was initiated, and in 2018, the leaf-mining fly, Hydrellia egeriae Rodrigues (Diptera: Ephydridae) was released. This was the first release of a biological control agent against E. densa in the world, and the first agent released against a submerged aquatic weed in South Africa. This thesis comprises the subsequent step of a biological control program when permission for the release of an agent have been obtained. A brief history of macrophyte invasions in South Africa’s unique freshwater systems are given in the literature review. Contributing factors to secondary invasions within the context of ecological resilience are introduced. An argument for the benefit of biological control as nuisance control is given, especially because E. densa and its natural enemy, H. egeriae is the focus species of this thesis. The main goal after permission for the release of an agent have been obtained, is to establish and build-up field populations. Research questions in this thesis aimed to investigate factors that contribute to or negate this goal. Through laboratory and field experiments we investigated the thermal physiology of the agent, and its climatic suitability to its novel range; different release strategies on field establishment and biotic resistance through the acquisition of novel parasitoids. Considering the longevity of this biological control program, we investigated the effects of elevated CO2 on the interaction between E. densa and H. egeriae through open top chamber experiments. Laboratory thermal physiology results showed that the agent is able to survive, develop and proliferate at all E. densa sites throughout the year. This is confirmed with the establishment of the agent at two release sites, the Nahoon River in the Eastern Cape Province and the Midmar Dam in KwaZulu-Natal. Post-release surveys showed that H. egeriae requires augmentative releases to sustain field populations. Without augmentative releases, H. egeriae herbivory levels were almost negligent. However, a contributing factor to low field-populations was parasitism. The biological control agent acquired three parasitoids, which have previously been described from Hydrellia lagarosiphon Deeming (Diptera: Ephydridae), a specific herbivore to Lagarosiphon major (Ridl.) Moss (Hydrocharitaceae). These results provide information on the immediate establishment and effectiveness of the H. egeriae. Results from the elevated CO2 study suggest that E. densa will become less nutritious through a shift in leaf C/N ratio, when ambient 800ppm is bubbled into experimental growth chambers. Hydrellia egeriae feeding was affected by ambient CO2 levels and plant nutrient availability. The set levels of ambient CO2 levels used in this experiment produced dissolved inorganic carbon levels that were lower than dissolved inorganic carbon levels in E. densa invaded sites. This suggests that, submerged aquatic plant-insect interactions may be harder to predict from only laboratory experiments. Further investigations are necessary to establish system-specific characteristics i.e. dissolved inorganic carbon and target plant nutritional quality. The biological control of E. densa in South Africa is still in its infancy. This study presents results from post-release surveys up until two years after the agent was released. From this study, Hydrellia egeriae exhibits the potential to be an effective biological control agent, but release strategies should be adapted to sustain field populations and to limit field parasitism effects. Continued post-release surveys will provide a more comprehensive idea of the seasonal fluctuations of field-populations and parasitism. Surveys at multiple sites will provide information on potential site specific characteristics that contribute to or negate biological effort. Considering the high nutrient status of South African freshwater systems, a more holistic approach to E. densa management is necessary. This will require the strengthening of ecological resilience to prevent systems from shifting into an alternate invasive stable state. In addition, aquatic weed management needs to be addressed by a resilient social network, which ultimately calls for the strengthening of socio-ecological resilience. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2021
- Full Text:
- Date Issued: 2021-10-29
The construction of phthalocyanine- carbon nanoparticle conjugates for applications in photodynamic therapy and non-linear optics
- Matshitse, Refilwe Manyama Stephina
- Authors: Matshitse, Refilwe Manyama Stephina
- Date: 2021-10-29
- Subjects: Phthalocyanines , Nanodiamonds , Photochemotherapy , Nonlinear optics , Quantum dots
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/188397 , vital:44750 , 10.21504/10962/188397
- Description: The syntheses and characterization of symmetric and asymmetric Pcs functionalized at the peripheral position and sometimes positively charged are reported. The Pcs had either H2, zinc or silicon as central metals and have pyridyloxy, benzothiozole phenoxy, and respective cationic analogues as ring substituents. The Pcs were linked to carbon based nanoparticles such as graphene quantum dots, carbon dots, and detonation nanodiamonds (DNDs) via an ester, amide bond and/or π - π stacking. The physicochemical characteristics of the Pcs were assessed when alone and when in a conjugated system. Both symmetrically and asymmetrically substituted benzothiozole Pcs when quaternised displayed higher triplet and singlet oxygen quantum yields than their unquaternised counterparts. Linkage to carbon nanoparticles (especially to detonation nanodiamonds) had an increasing effect on triplet and singlet oxygen quantum yield. However, a general decrease in singlet oxygen quantum yield on linkage to doped detonation nanodiamonds was associated with the screening effect of DNDs. Heteroatom doped DNDs-Pc nanohybrids have less singlet oxygen than Pcs alone due to molecular structural stability associated with strain that is relatively reduced upon linking Pcs. The In vitro dark cytotoxicity and photodynamic therapy of selected Pc complexes and conjugates against MCF-7 cells was tested. All studied Pc complexes and conjugates showed minimum dark toxicity making them applicable for PDT. When Pc complexes are alone, there is less phototoxicity with >22% cell viability at concentrations ≤ 50 μg/mL relative to conjugates with <22% cell viability at concentrations ≤ 50 μg/mL. There was no direct relationship between PDT and singlet oxygen quantum yields. Nonlinear optical characteristics of complexes was improved upon conjugation of DNDs. Absorbance, input energy, percentage loading, central metal, substituent of Pc and nature of interaction (covalent, noncovalent) are amongst some of the factors that influence nonlinear absorption properties of materials used in this study. All materials followed reverse saturable absorption through two photon absorption mechanism at the excitation wavelength of 532 nm. Aggregates reduce excited state lifetime and Beff under high concentrations/absorbance. A direct relationship between absorbance and Beff of DNDs nanoconjugated systems at low concentrations result in increased optical limiting characteristics of materials. The findings from this work show the importance of linking (nonlinear optics and photodynamic therapy) and doping (photodynamic therapy) photosensitisers such as phthalocyanines and sometimes boron dipyrromethenes onto carbon based nanoparticles for the enhanced characteristics in variable applications. , Thesis (PhD) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Matshitse, Refilwe Manyama Stephina
- Date: 2021-10-29
- Subjects: Phthalocyanines , Nanodiamonds , Photochemotherapy , Nonlinear optics , Quantum dots
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/188397 , vital:44750 , 10.21504/10962/188397
- Description: The syntheses and characterization of symmetric and asymmetric Pcs functionalized at the peripheral position and sometimes positively charged are reported. The Pcs had either H2, zinc or silicon as central metals and have pyridyloxy, benzothiozole phenoxy, and respective cationic analogues as ring substituents. The Pcs were linked to carbon based nanoparticles such as graphene quantum dots, carbon dots, and detonation nanodiamonds (DNDs) via an ester, amide bond and/or π - π stacking. The physicochemical characteristics of the Pcs were assessed when alone and when in a conjugated system. Both symmetrically and asymmetrically substituted benzothiozole Pcs when quaternised displayed higher triplet and singlet oxygen quantum yields than their unquaternised counterparts. Linkage to carbon nanoparticles (especially to detonation nanodiamonds) had an increasing effect on triplet and singlet oxygen quantum yield. However, a general decrease in singlet oxygen quantum yield on linkage to doped detonation nanodiamonds was associated with the screening effect of DNDs. Heteroatom doped DNDs-Pc nanohybrids have less singlet oxygen than Pcs alone due to molecular structural stability associated with strain that is relatively reduced upon linking Pcs. The In vitro dark cytotoxicity and photodynamic therapy of selected Pc complexes and conjugates against MCF-7 cells was tested. All studied Pc complexes and conjugates showed minimum dark toxicity making them applicable for PDT. When Pc complexes are alone, there is less phototoxicity with >22% cell viability at concentrations ≤ 50 μg/mL relative to conjugates with <22% cell viability at concentrations ≤ 50 μg/mL. There was no direct relationship between PDT and singlet oxygen quantum yields. Nonlinear optical characteristics of complexes was improved upon conjugation of DNDs. Absorbance, input energy, percentage loading, central metal, substituent of Pc and nature of interaction (covalent, noncovalent) are amongst some of the factors that influence nonlinear absorption properties of materials used in this study. All materials followed reverse saturable absorption through two photon absorption mechanism at the excitation wavelength of 532 nm. Aggregates reduce excited state lifetime and Beff under high concentrations/absorbance. A direct relationship between absorbance and Beff of DNDs nanoconjugated systems at low concentrations result in increased optical limiting characteristics of materials. The findings from this work show the importance of linking (nonlinear optics and photodynamic therapy) and doping (photodynamic therapy) photosensitisers such as phthalocyanines and sometimes boron dipyrromethenes onto carbon based nanoparticles for the enhanced characteristics in variable applications. , Thesis (PhD) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10-29
The dark side of emotional labour of South African Police Service officers, working in KwaZulu-Natal
- Authors: Thwala, Fezeka Asande
- Date: 2021-10-29
- Subjects: Police South Africa , Police Attitudes , Police Job stress South Africa KwaZulu-Natal , Police psychology South Africa KwaZulu-Natal , Police Social conditions , Anger , Aggressiveness , Intimidation , Employee morale South Africa KwaZulu-Natal , Work environment South Africa KwaZulu-Natal , Corporate culture South Africa KwaZulu-Natal
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190950 , vital:45044
- Description: This research paper explores the concept of emotional labour through the lens of the dark side of emotional labour, which includes emotions such as anger, aggression, intimidation, and neutrality. The concept of the dark side of emotional labour seeks to investigate the experiences and effects the performance of these emotions has on police officers as required by the SAPS organisation. These experiences are explored using three central themes: emotional neutrality, emotional toxicity, and emotionally dirty work. This paper places emphasis on emotional labour not only restricted to the performance of positive emotions such as smiling and presentable appearance such as Arlie Hochschild (1983) account of air hostesses but also extending to the expectation or requirement for the performance of dark emotions, which is quite evident in the case of police officers. This study was conducted in KwaZulu Natal, with Police Officers that have acquired the necessary training to be police officers and have worked a minimum of 2 years. The research methodology used was qualitative, and data were obtained from semi-structured interviews. These were then analysed and presented in line with the research objectives. The research found evidence of how individuals' different positions influence how frequently they perform and express negative emotions. It found that the gender difference also contributes to the diverse experiences of dark emotions. Furthermore, it found that the continuous experience of negative emotions has, to an extent, affected the police officers in their lives outside of the organisation. This study concluded by discussing the implications and recommendations for further research. , Thesis (MSocSci) -- Faculty of Humanities, Sociology, 2021
- Full Text:
- Date Issued: 2021-10-29
The dark side of emotional labour of South African Police Service officers, working in KwaZulu-Natal
- Authors: Thwala, Fezeka Asande
- Date: 2021-10-29
- Subjects: Police South Africa , Police Attitudes , Police Job stress South Africa KwaZulu-Natal , Police psychology South Africa KwaZulu-Natal , Police Social conditions , Anger , Aggressiveness , Intimidation , Employee morale South Africa KwaZulu-Natal , Work environment South Africa KwaZulu-Natal , Corporate culture South Africa KwaZulu-Natal
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190950 , vital:45044
- Description: This research paper explores the concept of emotional labour through the lens of the dark side of emotional labour, which includes emotions such as anger, aggression, intimidation, and neutrality. The concept of the dark side of emotional labour seeks to investigate the experiences and effects the performance of these emotions has on police officers as required by the SAPS organisation. These experiences are explored using three central themes: emotional neutrality, emotional toxicity, and emotionally dirty work. This paper places emphasis on emotional labour not only restricted to the performance of positive emotions such as smiling and presentable appearance such as Arlie Hochschild (1983) account of air hostesses but also extending to the expectation or requirement for the performance of dark emotions, which is quite evident in the case of police officers. This study was conducted in KwaZulu Natal, with Police Officers that have acquired the necessary training to be police officers and have worked a minimum of 2 years. The research methodology used was qualitative, and data were obtained from semi-structured interviews. These were then analysed and presented in line with the research objectives. The research found evidence of how individuals' different positions influence how frequently they perform and express negative emotions. It found that the gender difference also contributes to the diverse experiences of dark emotions. Furthermore, it found that the continuous experience of negative emotions has, to an extent, affected the police officers in their lives outside of the organisation. This study concluded by discussing the implications and recommendations for further research. , Thesis (MSocSci) -- Faculty of Humanities, Sociology, 2021
- Full Text:
- Date Issued: 2021-10-29
The de novo biosynthesis of biotin is required for the optimal growth of Salmonella enterica serovar Typhimurium in the intracellular environment
- Authors: McLaughlin, Claire
- Date: 2021-10-29
- Subjects: Salmonella , Biotin , Biosynthesis , Salmonella typhimurium , Antibacterial agents , Anti-infective agents , Pathogenic bacteria , Salmonella food poisoning
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192097 , vital:45195
- Description: Salmonella enterica serovar Typhimurium (S. Typhimurium) is a foodborne pathogen infecting humans and animals, contributing to significant morbidity and mortality worldwide each year. The increase in antibiotic-resistant S. Typhimurium infections in recent years has highlighted the need for new antibacterial drugs and drug targets. S. Typhimurium can acquire biotin through de novo biosynthesis or via transport from its extracellular environment. The importance of the vitamin for bacterial survival, coupled with the absence of the biotin biosynthetic pathway in humans, makes the biotin biosynthetic enzymes attractive targets for drug discovery. The study's primary aim was to determine the relative importance of the biotin biosynthesis and transport pathways for the in vitro and ex vivo growth and survival of S. Typhimurium, with the goal of validating the pathways as valid targets for antimicrobial drug development. In order to achieve this aim, we generated S. Typhimurium mutant strains harbouring deletions in either the biotin biosynthetic gene, bioB, or putative high-affinity biotin transporter, yigM (ΔbioB and ΔyigM, respectively), as well as a double mutant in which the two mutations were combined (ΔbioB ΔyigM). Since the simultaneous disruption of biotin biosynthesis and transport in the double mutant may form a synthetic lethal combination, preventing further analysis of the strain, we also constructed a conditional mutant in which the promoter of the yigM gene was replaced by the arabinose-regulatable, PBAD promoter in the ΔbioB background (ΔbioB PBAD::yigM). Since the expression of the YigM in this strain is arabinose-regulatable, its role as a biotin transporter can be evaluated by altering the arabinose concentration in the growth media. Once the mutant strains were isolated and verified genetically, their growth and that of their genetically complemented counterparts were analysed in liquid and/or solid M9 minimal medium in the absence of biotin. Consistent with previous observations, the ΔbioB auxotrophic mutant's growth was severely compromised in minimal media in the absence of biotin. The growth of the strain could, however, be restored by supplementation with exogenous biotin or expression of the wild type bioB gene from an episomal plasmid. The ability of biotin to reverse the growth defect of the ΔbioB mutant strain was, however, dependent on the presence of a functional YigM, since biotin supplementation did not affect the growth of the ΔbioB ΔyigM double mutant strain. The introduction of a second copy of the yigM gene in the ΔbioB ΔyigM background, however, restored the growth of the strain in the presence, but not absence, of biotin. The dependence of the double mutant on both YigM and biotin for growth supports the idea that the protein functions as the sole or primary biotin transporter in S. Typhimurium, as it has recently been shown for E. coli (Ringsletter, 2010; Finkenwirth et al, 2013). The essentiality of YigM for biotin transport was subsequently verified by two independent means. Firstly, the growth of the ΔbioB PBAD::yigM promoter-replacement mutant was strictly dependent on the inclusion of arabinose in biotin-supplemented M9 minimal media supplemented, indicating that the expression of YigM from the PBAD promoter is essential for biotin transport. Secondly, following treatment with a known small-molecule inhibitor of the biotin biosynthesis, MAC-13772, exogenous biotin was capable of restoring the growth defect of the YigM+ wild type S. Typhimurium strain, but not the YigM− ΔyigM mutant. Taken together, these findings confirm that YigM serves as the biotin transporter for S. Typhimurium and that the corresponding ΔyigM mutant is, as a result, defective for biotin transport. Having confirmed the genotypes and phenotypes of the ΔbioB, ΔyigM, and ΔbioB ΔyigM mutants, we next analysed the importance of the biotin biosynthesis and transport pathways for the growth and survival of S. Typhimurium within the intracellular environment. To this end, we determined the proliferation of each of the mutant strains following infection of HeLa epithelial and RAW264.7 macrophage-like cell lines. Our results revealed that the de novo biosynthesis of biotin is required for the optimal growth of S. Typhimurium following infection of both epithelial and macrophage-like cell lines. Disruption of biotin transport, by contrast, had no significant effect on the intracellular proliferation of S. Typhimurium when a functional pathway for the biosynthesis of biotin was present. The simultaneous disruption of biotin biosynthesis and transport, however, resulted in significant attenuation of S. Typhimurium in epithelial cells, while bacterial survival in macrophages decreased to below the limit of detection. Overall, our results suggest the S. Typhimurium relies primarily on biotin produced by the de novo biosynthesis pathway to support its growth in the intracellular environment. While YigM-mediated biotin transport is essential for sustaining the viability of intracellular S. Typhimurium in the absence of de novo biosynthesis, it appears to play a relatively minor role in the acquisition of biotin during growth in the nutrient-limited Salmonella containing vacuole. Our findings suggest that inhibiting biotin biosynthesis may be a viable strategy for combating systemic infections caused by Salmonella, as has been recently proposed for other medically important bacterial pathogens (Carfrae et al., 2020). , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: McLaughlin, Claire
- Date: 2021-10-29
- Subjects: Salmonella , Biotin , Biosynthesis , Salmonella typhimurium , Antibacterial agents , Anti-infective agents , Pathogenic bacteria , Salmonella food poisoning
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192097 , vital:45195
- Description: Salmonella enterica serovar Typhimurium (S. Typhimurium) is a foodborne pathogen infecting humans and animals, contributing to significant morbidity and mortality worldwide each year. The increase in antibiotic-resistant S. Typhimurium infections in recent years has highlighted the need for new antibacterial drugs and drug targets. S. Typhimurium can acquire biotin through de novo biosynthesis or via transport from its extracellular environment. The importance of the vitamin for bacterial survival, coupled with the absence of the biotin biosynthetic pathway in humans, makes the biotin biosynthetic enzymes attractive targets for drug discovery. The study's primary aim was to determine the relative importance of the biotin biosynthesis and transport pathways for the in vitro and ex vivo growth and survival of S. Typhimurium, with the goal of validating the pathways as valid targets for antimicrobial drug development. In order to achieve this aim, we generated S. Typhimurium mutant strains harbouring deletions in either the biotin biosynthetic gene, bioB, or putative high-affinity biotin transporter, yigM (ΔbioB and ΔyigM, respectively), as well as a double mutant in which the two mutations were combined (ΔbioB ΔyigM). Since the simultaneous disruption of biotin biosynthesis and transport in the double mutant may form a synthetic lethal combination, preventing further analysis of the strain, we also constructed a conditional mutant in which the promoter of the yigM gene was replaced by the arabinose-regulatable, PBAD promoter in the ΔbioB background (ΔbioB PBAD::yigM). Since the expression of the YigM in this strain is arabinose-regulatable, its role as a biotin transporter can be evaluated by altering the arabinose concentration in the growth media. Once the mutant strains were isolated and verified genetically, their growth and that of their genetically complemented counterparts were analysed in liquid and/or solid M9 minimal medium in the absence of biotin. Consistent with previous observations, the ΔbioB auxotrophic mutant's growth was severely compromised in minimal media in the absence of biotin. The growth of the strain could, however, be restored by supplementation with exogenous biotin or expression of the wild type bioB gene from an episomal plasmid. The ability of biotin to reverse the growth defect of the ΔbioB mutant strain was, however, dependent on the presence of a functional YigM, since biotin supplementation did not affect the growth of the ΔbioB ΔyigM double mutant strain. The introduction of a second copy of the yigM gene in the ΔbioB ΔyigM background, however, restored the growth of the strain in the presence, but not absence, of biotin. The dependence of the double mutant on both YigM and biotin for growth supports the idea that the protein functions as the sole or primary biotin transporter in S. Typhimurium, as it has recently been shown for E. coli (Ringsletter, 2010; Finkenwirth et al, 2013). The essentiality of YigM for biotin transport was subsequently verified by two independent means. Firstly, the growth of the ΔbioB PBAD::yigM promoter-replacement mutant was strictly dependent on the inclusion of arabinose in biotin-supplemented M9 minimal media supplemented, indicating that the expression of YigM from the PBAD promoter is essential for biotin transport. Secondly, following treatment with a known small-molecule inhibitor of the biotin biosynthesis, MAC-13772, exogenous biotin was capable of restoring the growth defect of the YigM+ wild type S. Typhimurium strain, but not the YigM− ΔyigM mutant. Taken together, these findings confirm that YigM serves as the biotin transporter for S. Typhimurium and that the corresponding ΔyigM mutant is, as a result, defective for biotin transport. Having confirmed the genotypes and phenotypes of the ΔbioB, ΔyigM, and ΔbioB ΔyigM mutants, we next analysed the importance of the biotin biosynthesis and transport pathways for the growth and survival of S. Typhimurium within the intracellular environment. To this end, we determined the proliferation of each of the mutant strains following infection of HeLa epithelial and RAW264.7 macrophage-like cell lines. Our results revealed that the de novo biosynthesis of biotin is required for the optimal growth of S. Typhimurium following infection of both epithelial and macrophage-like cell lines. Disruption of biotin transport, by contrast, had no significant effect on the intracellular proliferation of S. Typhimurium when a functional pathway for the biosynthesis of biotin was present. The simultaneous disruption of biotin biosynthesis and transport, however, resulted in significant attenuation of S. Typhimurium in epithelial cells, while bacterial survival in macrophages decreased to below the limit of detection. Overall, our results suggest the S. Typhimurium relies primarily on biotin produced by the de novo biosynthesis pathway to support its growth in the intracellular environment. While YigM-mediated biotin transport is essential for sustaining the viability of intracellular S. Typhimurium in the absence of de novo biosynthesis, it appears to play a relatively minor role in the acquisition of biotin during growth in the nutrient-limited Salmonella containing vacuole. Our findings suggest that inhibiting biotin biosynthesis may be a viable strategy for combating systemic infections caused by Salmonella, as has been recently proposed for other medically important bacterial pathogens (Carfrae et al., 2020). , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-10-29