Umzi ka Mama Family property transfer practices and the historical significance of title deeds to African female heads of household in Fingo Village: a participatory theatre approach
- Authors: Hellemann, Phemelo Cordelia
- Date: 2022-04-07
- Subjects: Public history South Africa Eastern Cape , Oral history South Africa Eastern Cape , Women Housing South Africa Eastern Cape , Feminism Africa , Apartheid Law and legislation South Africa , Participatory theater South Africa Eastern Cape , Playback theater , Theater and society South Africa Eastern Cape , History Citizen participation , South Africa. Group Areas Act, 1950
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/294537 , vital:57230 , DOI https://doi.org/10.21504/10962/294537
- Description: Many everyday stories and experiences of African women remain underrepresented and undocumented. For example, the omission of Fingo Village women’s names from official deeds records silenced their voices. African women faced gender and racial discrimination that denied them fundamental human rights and limited their participation in urban life. Title deed records constitute one type of public record where African women’s names were omitted for centuries by the colonial and apartheid governments. Under apartheid, African women occupied the social status of minors; hence, the government denied them urban land rights. This African feminist study enlists narratives of a sample of seven African female heads of households residing in Fingo Village who are also property owners. Fingo Village is an atypical environment where African people had a rare legal advantage of owning title deeds dating back to 1855. This study employed an interdisciplinary approach by mixing oral history methodology and applied theatre methods to record, interpret and present Fingo Village women’s narratives of family property inheritance and the significance of title deed documentation in the suburb. The multiple technique approach created opportunities for authentic dialogue between the researcher and the participants beyond the inherent limitations of public history oral interviews. The traditional oral history interview and the participatory theatre methods helped uncover unconventional practices in family property relations. Though customary transfers of family homes to custodians were prevalent, title deed registration of family property was also acknowledged as a vital practice that empowered women legally. The researcher used participatory theatre techniques inspired by playback, image and forum theatre to enhance the researcher and participants’ relationship. These methods encouraged the researcher and respondents’ shared authority as they embarked on an extended participatory research project. In this regard, through dialogical and performance-based activities, the participants and the researcher became co-creators of untold Fingo Village stories. Moreover, the theatre techniques became interpretation and analysis tools that ensured that the participants’ untold stories were well represented. The first phase of the research involved engaging with the literature about the title deeds history of Fingo Village and conducting oral history interviews that served as data. In the second phase, the interviews were analysed and packaged in a documentary format. The third phase was a playback theatre inspired session in a 10-minute performance based on themes from the participants’ filmed interviews. Additionally, the performance was a catalyst for forum theatre activities that allowed the participants to interact with the performer and suggest solutions to the dilemma posed by the performer regarding family property use. The participants were decision-makers and family property relations experts within this imagined context. In the fourth phase, the image theatre adaptation and memory work activities were essential tools. The tools aided the visuals and information from an existing Fingo Village exhibition as additional resources that prompted dialogue and discussions. The exhibition encouraged participants to share their personal experiences and memories of the Group Areas Act (GAA) era. The findings showed that the GAA era saw many families revert to communal tenure practices as a strategy to evade forced sales; as such, this gave rise to undocumented family property transfers. Additionally, the findings revealed that though customary practices are often patriarchal, there are circumstances favouring women as the preferred family property custodian. These are embedded in the social status of women who are traditional healers, firstborn daughters, and those from families with just daughters. This study contributes to the growing literature that advocates for positive representation of African women’s stories by using active research methodologies that strengthen partnerships and shared authority between the researcher and the public. This methodology could inspire other researchers to explore theatre techniques to create more profound and meaningful engagements with their participants. The links to the video materials accompanying this thesis are provided on the contents page. , Thesis (PhD) -- Faculty of Humanities, History, 2022
- Full Text:
- Date Issued: 2022-04-07
- Authors: Hellemann, Phemelo Cordelia
- Date: 2022-04-07
- Subjects: Public history South Africa Eastern Cape , Oral history South Africa Eastern Cape , Women Housing South Africa Eastern Cape , Feminism Africa , Apartheid Law and legislation South Africa , Participatory theater South Africa Eastern Cape , Playback theater , Theater and society South Africa Eastern Cape , History Citizen participation , South Africa. Group Areas Act, 1950
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/294537 , vital:57230 , DOI https://doi.org/10.21504/10962/294537
- Description: Many everyday stories and experiences of African women remain underrepresented and undocumented. For example, the omission of Fingo Village women’s names from official deeds records silenced their voices. African women faced gender and racial discrimination that denied them fundamental human rights and limited their participation in urban life. Title deed records constitute one type of public record where African women’s names were omitted for centuries by the colonial and apartheid governments. Under apartheid, African women occupied the social status of minors; hence, the government denied them urban land rights. This African feminist study enlists narratives of a sample of seven African female heads of households residing in Fingo Village who are also property owners. Fingo Village is an atypical environment where African people had a rare legal advantage of owning title deeds dating back to 1855. This study employed an interdisciplinary approach by mixing oral history methodology and applied theatre methods to record, interpret and present Fingo Village women’s narratives of family property inheritance and the significance of title deed documentation in the suburb. The multiple technique approach created opportunities for authentic dialogue between the researcher and the participants beyond the inherent limitations of public history oral interviews. The traditional oral history interview and the participatory theatre methods helped uncover unconventional practices in family property relations. Though customary transfers of family homes to custodians were prevalent, title deed registration of family property was also acknowledged as a vital practice that empowered women legally. The researcher used participatory theatre techniques inspired by playback, image and forum theatre to enhance the researcher and participants’ relationship. These methods encouraged the researcher and respondents’ shared authority as they embarked on an extended participatory research project. In this regard, through dialogical and performance-based activities, the participants and the researcher became co-creators of untold Fingo Village stories. Moreover, the theatre techniques became interpretation and analysis tools that ensured that the participants’ untold stories were well represented. The first phase of the research involved engaging with the literature about the title deeds history of Fingo Village and conducting oral history interviews that served as data. In the second phase, the interviews were analysed and packaged in a documentary format. The third phase was a playback theatre inspired session in a 10-minute performance based on themes from the participants’ filmed interviews. Additionally, the performance was a catalyst for forum theatre activities that allowed the participants to interact with the performer and suggest solutions to the dilemma posed by the performer regarding family property use. The participants were decision-makers and family property relations experts within this imagined context. In the fourth phase, the image theatre adaptation and memory work activities were essential tools. The tools aided the visuals and information from an existing Fingo Village exhibition as additional resources that prompted dialogue and discussions. The exhibition encouraged participants to share their personal experiences and memories of the Group Areas Act (GAA) era. The findings showed that the GAA era saw many families revert to communal tenure practices as a strategy to evade forced sales; as such, this gave rise to undocumented family property transfers. Additionally, the findings revealed that though customary practices are often patriarchal, there are circumstances favouring women as the preferred family property custodian. These are embedded in the social status of women who are traditional healers, firstborn daughters, and those from families with just daughters. This study contributes to the growing literature that advocates for positive representation of African women’s stories by using active research methodologies that strengthen partnerships and shared authority between the researcher and the public. This methodology could inspire other researchers to explore theatre techniques to create more profound and meaningful engagements with their participants. The links to the video materials accompanying this thesis are provided on the contents page. , Thesis (PhD) -- Faculty of Humanities, History, 2022
- Full Text:
- Date Issued: 2022-04-07
Understanding trance states from the perspective of South African traditional healers - in relation to psychosis
- Authors: Masia, Ntombifuthi Thato
- Date: 2022-04-07
- Subjects: Trance , Psychoses , Altered states of consciousness , Healers South Africa , Healers South Africa Attitudes , Mental health services South Africa , Psychoses Alternative treatment , Psychoses Alternative treatment Moral and ethical aspects
- Language: English
- Type: Master's article , text
- Identifier: http://hdl.handle.net/10962/232877 , vital:50034
- Description: Studies conducted on psychosis, sleep and trance states have indicated that the phenomenon of trance occurs quite similarly to that of psychosis. Trance states (or, altered states of consciousness) are defined as mental states in which there is an alteration in the informational or representational relationships between consciousness and the world, whereby the mechanisms of consciousness have an increased tendency to produce misrepresentations like hallucinations, delusions and memory or temporal distortions. This research study aimed to contribute to the knowledge of trance states, particularly as represented by the language and social processes of traditional healers in South Africa, and as experienced by them. This knowledge is geared towards providing insight on the experience and treatment of the similarly occurring phenomenon of psychosis in clinical settings. Through a qualitative study, this research found that strategies of exploration, building recognition and familiarity, and self-monitoring are used by traditional healers to reduce the distress caused by intrusive and disruptive symptoms of trance, as well as to maintain a stable self-identity while experiencing trance states. , Thesis (MA) -- Humanities, Psychology, 2022
- Full Text:
- Date Issued: 2022-04-07
- Authors: Masia, Ntombifuthi Thato
- Date: 2022-04-07
- Subjects: Trance , Psychoses , Altered states of consciousness , Healers South Africa , Healers South Africa Attitudes , Mental health services South Africa , Psychoses Alternative treatment , Psychoses Alternative treatment Moral and ethical aspects
- Language: English
- Type: Master's article , text
- Identifier: http://hdl.handle.net/10962/232877 , vital:50034
- Description: Studies conducted on psychosis, sleep and trance states have indicated that the phenomenon of trance occurs quite similarly to that of psychosis. Trance states (or, altered states of consciousness) are defined as mental states in which there is an alteration in the informational or representational relationships between consciousness and the world, whereby the mechanisms of consciousness have an increased tendency to produce misrepresentations like hallucinations, delusions and memory or temporal distortions. This research study aimed to contribute to the knowledge of trance states, particularly as represented by the language and social processes of traditional healers in South Africa, and as experienced by them. This knowledge is geared towards providing insight on the experience and treatment of the similarly occurring phenomenon of psychosis in clinical settings. Through a qualitative study, this research found that strategies of exploration, building recognition and familiarity, and self-monitoring are used by traditional healers to reduce the distress caused by intrusive and disruptive symptoms of trance, as well as to maintain a stable self-identity while experiencing trance states. , Thesis (MA) -- Humanities, Psychology, 2022
- Full Text:
- Date Issued: 2022-04-07
‘They do not understand us’: a psychosocial analysis of the everyday lived experiences of a CYCC care worker in semi-rural South Africa
- Authors: Pieters, Cinnamon-Paige
- Date: 2022-04-07
- Subjects: Child care workers South Africa Attitudes , Narrative inquiry (Research method) , Intersubjectivity , Free association (Psychology) , Child care South Africa Psychological aspects , Burn out (Psychology) South Africa
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/294482 , vital:57225
- Description: This paper employs a psychosocial framework to analyse the everyday lived experiences of a child and youth care worker in semi-rural South Africa. The aim is to provide a new perspective of care work by drawing on narrative analysis alongside a psychoanalytic approach to qualitative research. With an emphasis on the socially constructed nature of reality, the researcher aims to elucidate the rich unconscious depths of being a care worker and the dynamics of the intersubjective reality of care work. Employing a free association narrative interview technique allows the researcher to gain understanding of the narratives that the care worker draws on in the construction of his identity as a care worker. The use of a psychosocial approach enables the researcher to pay attention to both the social context that influences the narratives that he draws on, but also the psychological ‘pay offs’ of these constructions. Most notably, the study highlights how the care worker’s identity is mediated by a defended subjectivity and argues that his failures in mentalization might stem from the way he is treated as a care worker by other professionals as a result of their mindblindness. This maintains his narrative of invisibility, and the pervasive feeling of being misunderstood as a professional in his own right. The findings are discussed in terms of their contribution to understanding some of the challenges that CYCC care workers face. , Research Article (MA) -- Faculty of Humanities, Psychology, 2022
- Full Text:
- Date Issued: 2022-04-07
- Authors: Pieters, Cinnamon-Paige
- Date: 2022-04-07
- Subjects: Child care workers South Africa Attitudes , Narrative inquiry (Research method) , Intersubjectivity , Free association (Psychology) , Child care South Africa Psychological aspects , Burn out (Psychology) South Africa
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/294482 , vital:57225
- Description: This paper employs a psychosocial framework to analyse the everyday lived experiences of a child and youth care worker in semi-rural South Africa. The aim is to provide a new perspective of care work by drawing on narrative analysis alongside a psychoanalytic approach to qualitative research. With an emphasis on the socially constructed nature of reality, the researcher aims to elucidate the rich unconscious depths of being a care worker and the dynamics of the intersubjective reality of care work. Employing a free association narrative interview technique allows the researcher to gain understanding of the narratives that the care worker draws on in the construction of his identity as a care worker. The use of a psychosocial approach enables the researcher to pay attention to both the social context that influences the narratives that he draws on, but also the psychological ‘pay offs’ of these constructions. Most notably, the study highlights how the care worker’s identity is mediated by a defended subjectivity and argues that his failures in mentalization might stem from the way he is treated as a care worker by other professionals as a result of their mindblindness. This maintains his narrative of invisibility, and the pervasive feeling of being misunderstood as a professional in his own right. The findings are discussed in terms of their contribution to understanding some of the challenges that CYCC care workers face. , Research Article (MA) -- Faculty of Humanities, Psychology, 2022
- Full Text:
- Date Issued: 2022-04-07
An eco-physiological investigation of fisheries-induced evolution: comparing the resilience of larvae from exploited and unexploited commercial reef fish populations to projected ocean acidification
- Authors: Muller, Cuen
- Date: 2022-04-08
- Subjects: Ocean acidification , Fishes Climatic factors , Fishes Physiology , Fishes Metabolism , Fishes Respiration , Fishes Larvae , Fishery management , Chrysoblephus laticeps (Red roman)
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232579 , vital:50004 , DOI 10.21504/10962/232579
- Description: It is now accepted that anthropogenic-induced climate change is resulting in unprecedented rates of change to marine environments. Marine organisms are being challenged by rapidly increasing temperatures, acidification, expansion of oxygen dead zones, and higher frequencies and magnitudes of extreme weather events. Exploited fish populations are also undergoing selective harvesting. Certain traits, such as large size, fast growth, and/or bold/active behaviours, are being actively targeted and removed from the population gene pool. This selective removal of individuals may compromise the capacity of fish populations to resist or recover from environmental disturbances and reduce their ability to adapt to a changing environment as many of these traits are heritable. As most marine fishes' embryonic and larval stages represent the period when individuals are most sensitive to environmental disturbances, they are a critical bottleneck to population persistence in the face of exploitation and climate change. This thesis aimed to quantify and compare the metabolic physiology, growth, and development of an exploited and endemic sparid, the roman seabream Chrysoblephus laticeps, during the early larval stages under 1) ocean acidification conditions expected by the year 2100 and 2) from populations experiencing dissimilar rates of exploitation. To quantify and compare the physiology of larvae, adult C. laticeps from an exploited population were captured and field-spawned. Fertilised eggs were placed into either control/present-day conditions (pH = 8.03, pCO2 ≈ 420 μatm) or high-pCO2/hypercapnic treatment conditions (pH = 7.63, pCO2 ≈ 1400 μatm). The metabolic physiology of individual larvae was determined using a novel rolling-regression technique on static respirometry data. Here, estimates of the minimum and maximum oxygen consumption rates (VO2) could be determined with high test-retest reliability. The very early developmental stages (yolk-sac stage) appeared resilient to high pCO2 conditions despite being exposed to treatment conditions throughout the embryonic stage. Preflexion larvae showed sensitivity to treatment conditions by exhibiting reduced metabolic and growth rates, consistent with metabolic depression, associated with environmental stress. However, by the onset of flexion, which coincides with gill development, acid-base regulation, and muscle differentiation, metabolic and growth rates of treatment larvae were significantly greater than that of controls. This suggests that acid-base regulation imposes a high cost to maintain internal pH homeostasis. Importantly, these elevated metabolic costs were likely mediated through increased feeding rates in experimental conditions where food was ad libitum. In natural conditions, where food availability may be varied, high pCO2 conditions could be associated with higher mortality rates. Based on evidence that protected/unexploited populations are more genetically diverse and are composed of individuals representing a greater range of metabolic phenotypes, offspring were collected from a protected population experiencing otherwise similar environmental conditions to the exploited population. Metabolic rates of control larvae were generally similar to those of the exploited population. However, minimum rates of VO2 were typically higher for larvae from the protected population at comparable life stages. Preflexion treatment larvae from the protected population did not appear to undergo a period of reduced metabolism or growth compared to their control counterparts. While metabolic rates at the onset of flexion were significantly higher for treatment larvae, this was not associated with growth differences. Growth over-compensation following periods of growth depression is often associated with deleterious effects, such as organ damage and body or developmental malformations. This suggests somewhat improved resilience to ocean acidification conditions. This thesis found evidence that larval C. laticeps are sensitive to ocean acidification conditions expected by 2100. When this stressor is combined with increasing thermal variability, changing current coastal regimes, and heterogeneous food availability, also expected to occur by 2100, ocean acidification may compromise the population persistence of this species. However, an energetics approach to stress-tolerance suggests that larvae from the protected population may inherently show greater resilience to climate change-related environmental stressors. Evidence that exploitation affects the resilience of fish larvae to climate change highlights the need for an evolutionary approach to fisheries management and the importance of spatial protection in maintaining larger and more resilient populations while providing the raw material essential for adaptation. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Muller, Cuen
- Date: 2022-04-08
- Subjects: Ocean acidification , Fishes Climatic factors , Fishes Physiology , Fishes Metabolism , Fishes Respiration , Fishes Larvae , Fishery management , Chrysoblephus laticeps (Red roman)
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232579 , vital:50004 , DOI 10.21504/10962/232579
- Description: It is now accepted that anthropogenic-induced climate change is resulting in unprecedented rates of change to marine environments. Marine organisms are being challenged by rapidly increasing temperatures, acidification, expansion of oxygen dead zones, and higher frequencies and magnitudes of extreme weather events. Exploited fish populations are also undergoing selective harvesting. Certain traits, such as large size, fast growth, and/or bold/active behaviours, are being actively targeted and removed from the population gene pool. This selective removal of individuals may compromise the capacity of fish populations to resist or recover from environmental disturbances and reduce their ability to adapt to a changing environment as many of these traits are heritable. As most marine fishes' embryonic and larval stages represent the period when individuals are most sensitive to environmental disturbances, they are a critical bottleneck to population persistence in the face of exploitation and climate change. This thesis aimed to quantify and compare the metabolic physiology, growth, and development of an exploited and endemic sparid, the roman seabream Chrysoblephus laticeps, during the early larval stages under 1) ocean acidification conditions expected by the year 2100 and 2) from populations experiencing dissimilar rates of exploitation. To quantify and compare the physiology of larvae, adult C. laticeps from an exploited population were captured and field-spawned. Fertilised eggs were placed into either control/present-day conditions (pH = 8.03, pCO2 ≈ 420 μatm) or high-pCO2/hypercapnic treatment conditions (pH = 7.63, pCO2 ≈ 1400 μatm). The metabolic physiology of individual larvae was determined using a novel rolling-regression technique on static respirometry data. Here, estimates of the minimum and maximum oxygen consumption rates (VO2) could be determined with high test-retest reliability. The very early developmental stages (yolk-sac stage) appeared resilient to high pCO2 conditions despite being exposed to treatment conditions throughout the embryonic stage. Preflexion larvae showed sensitivity to treatment conditions by exhibiting reduced metabolic and growth rates, consistent with metabolic depression, associated with environmental stress. However, by the onset of flexion, which coincides with gill development, acid-base regulation, and muscle differentiation, metabolic and growth rates of treatment larvae were significantly greater than that of controls. This suggests that acid-base regulation imposes a high cost to maintain internal pH homeostasis. Importantly, these elevated metabolic costs were likely mediated through increased feeding rates in experimental conditions where food was ad libitum. In natural conditions, where food availability may be varied, high pCO2 conditions could be associated with higher mortality rates. Based on evidence that protected/unexploited populations are more genetically diverse and are composed of individuals representing a greater range of metabolic phenotypes, offspring were collected from a protected population experiencing otherwise similar environmental conditions to the exploited population. Metabolic rates of control larvae were generally similar to those of the exploited population. However, minimum rates of VO2 were typically higher for larvae from the protected population at comparable life stages. Preflexion treatment larvae from the protected population did not appear to undergo a period of reduced metabolism or growth compared to their control counterparts. While metabolic rates at the onset of flexion were significantly higher for treatment larvae, this was not associated with growth differences. Growth over-compensation following periods of growth depression is often associated with deleterious effects, such as organ damage and body or developmental malformations. This suggests somewhat improved resilience to ocean acidification conditions. This thesis found evidence that larval C. laticeps are sensitive to ocean acidification conditions expected by 2100. When this stressor is combined with increasing thermal variability, changing current coastal regimes, and heterogeneous food availability, also expected to occur by 2100, ocean acidification may compromise the population persistence of this species. However, an energetics approach to stress-tolerance suggests that larvae from the protected population may inherently show greater resilience to climate change-related environmental stressors. Evidence that exploitation affects the resilience of fish larvae to climate change highlights the need for an evolutionary approach to fisheries management and the importance of spatial protection in maintaining larger and more resilient populations while providing the raw material essential for adaptation. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-04-08
An epistemic justice account of students’ experiences of feedback
- Authors: Vilakazi, Bella Phetheni
- Date: 2022-04-08
- Subjects: Feedback (Psychology) , Experience , Narrative inquiry (Research method) , Critical thinking , Caring Moral and ethical aspects , Epistemic access
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232599 , vital:50006 , DOI 10.21504/10962/232599
- Description: I am a storyteller. I believe in the power of stories to share experiences and to elucidate thoughts and ideas and to help us to make sense of complex social practices. This thesis includes the stories of five young women who were learning to become teachers. As they shared their stories with me, I share them with you. This study includes their stories of receiving feedback. These stories are structured within the Narrative Inquiry dimensions of temporality, place and context. These dimensions suggest that stories are historical and move through time, stories are shaped by place and the context in which they unfold (Clandinin, 2013). Furthermore, these stories demonstrate how feedback can serve to give access to powerful knowledge and can serve to recognise who our students are and what they bring to the academy (Hordern, 2018). But feedback can also serve to misrecognise. Much has been written and reported about the barriers preventing students from acting on the feedback on their assignment tasks in higher education. In this study, I argue that feedback is a pedagogic practice that can support students to gain epistemic access. Feedback can only achieve this if it makes the expectations explicit for students to make sense of and make meaning for themselves and if it is offered in a dialogical format which recognises the students, their attempts, their identities, and their knowledge. The research question of this study, ‘How do experiences of forms of feedback affect female undergraduate student teachers’ chances of epistemic access?’, is not unusual. There have been many research projects that have been carried out that examine students’ experiences of feedback (for example, Evans, 2013; Basey, Maines, & Francis, 2014; Nicol et al.; 2014; Carless, 2019; Winstone et al., 2021). But I identified a gap where feedback has not, to my knowledge, been studied directly through the lenses of Epistemic Justice towards Parity of Participation. This study interpreted five undergraduate student teachers’ feedback experiences through these lenses. Narrative inquiry enabled me to design this study in ways that foregrounded experience. Data was collected through multiple conversations during which I organised the participants’ life stories of feedback within the dimensions of temporality, place and context, and sociality. Miranda Fricker’s (2007) theory of Epistemic Justice and Fraser’s norm of Parity of Participation (2000) framed this study. I engaged with Fricker and Fraser’s literature meaningfully as a reader and researcher. I established an understanding of how the lenses offered by Fraser and Fricker allowed me to make sense of the literature more generally, in social life and on the pedagogic practice of feedback. Fricker’s theory of Epistemic Justice considers the epistemically unjust, gendered, raced and classed, experiences of epistemic agents. Fricker (2007) draws on two central concepts to account for epistemic injustices: Testimonial Injustice and Hermeneutical Injustice. Fricker (2007; 2003) explains that testimonial injustice occurs within a testimonial exchange setting, when an epistemic agent as a speaker gives testimony of the epistemic agent’s experiences and knowledge but is not awarded the credibility the speaker deserves (Fricker, 2003). Epistemic agents who participate in a testimonial exchange need to overcome bias and prejudice in order to evaluate testimonies with the degree of fairness the testimony deserves (Fricker, 2013; 2016). Hermeneutical injustice occurs when an epistemic agent is unable to make sense and make meaning of their social experiences. Hermeneutical injustice strengthens when the epistemic agent is prevented from gaining access to resources that might help with sense making and meaning making of these social experiences (Dielman, 2012; Fricker, 2016). To ensure that meaning can be made between people and groups of people, there needs to be some shared understandings of the purpose and process of sense making and meaning-making – or a willingness to co-create such shared understandings. Fraser’s norm of Participatory Parity enabled a consideration of the larger world of political and economic systems that give rise to social injustice. In this study, the theories of Fricker and Fraser are used to illuminate experiences of feedback of the five undergraduate student teachers who are the participants in this study and how these translate to epistemic and social injustice. The norm of Participatory Parity is considered where feedback allowed or restricted participants from participating on an equal footing in the feedback process. Narrative inquiry, a research methodology that is used to study experiences, was used to inform research strategies of this study. Participants’ experiences, data collection and organising the narratives demonstrated the dimensions of temporality and space. The thesis includes biographical vignettes for each of the participants in the study, interspersed with data from across all five participants. The key findings of this study show that feedback generally operates at the surface levels of grammar correction. In light of the theoretical lenses of this study, I argue that the feedback experiences they shared generally did not recognise their attempts and the identities and knowledges they brought to the tasks. Because the focus was on superficial correction of the specific task, the feedback failed to create conditions for the (re)distribution of knowledge. At times the feedback exerted power on participants. Because the feedback was generally in the form of one directional correction (with little space for interaction with the feedback or dialogue with the assessor), this caused status subordination of participants in the epistemic spaces of teaching practice. Lastly, the lack of clarity of feedback was harmful to the potential for dialogical feedback. Such feedback caused participants to experience forms of epistemic injustice in the form of hermeneutical injustice where it failed to create conditions for the distribution of knowledge. Feedback also caused participants to experience testimonial injustice where it failed to create conditions for recognising participants’ processes of sense-making and meaning-making in the various assignment tasks. Participatory Parity could not occur because the processes of recognition and redistribution were constrained. Feedback then created fertile conditions of epistemic injustice to occur, and participants were likely to have failed to gain the much needed epistemic access. This study is not the story of bad, uncaring academics; the study acknowledges the context of large classes and heavy workloads in which feedback is or is not given. Rather, this is the story of five women trying to make their way through the university and out into the world as teachers. The study calls for better theorising of feedback and more support for both academics and students to develop feedback literacy so that feedback might serve as a dialogical pedagogic practice that enables epistemic justice. , Thesis (PhD) -- Faculty of Education, Centre for Higher Education Research, Teaching and Learning, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Vilakazi, Bella Phetheni
- Date: 2022-04-08
- Subjects: Feedback (Psychology) , Experience , Narrative inquiry (Research method) , Critical thinking , Caring Moral and ethical aspects , Epistemic access
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232599 , vital:50006 , DOI 10.21504/10962/232599
- Description: I am a storyteller. I believe in the power of stories to share experiences and to elucidate thoughts and ideas and to help us to make sense of complex social practices. This thesis includes the stories of five young women who were learning to become teachers. As they shared their stories with me, I share them with you. This study includes their stories of receiving feedback. These stories are structured within the Narrative Inquiry dimensions of temporality, place and context. These dimensions suggest that stories are historical and move through time, stories are shaped by place and the context in which they unfold (Clandinin, 2013). Furthermore, these stories demonstrate how feedback can serve to give access to powerful knowledge and can serve to recognise who our students are and what they bring to the academy (Hordern, 2018). But feedback can also serve to misrecognise. Much has been written and reported about the barriers preventing students from acting on the feedback on their assignment tasks in higher education. In this study, I argue that feedback is a pedagogic practice that can support students to gain epistemic access. Feedback can only achieve this if it makes the expectations explicit for students to make sense of and make meaning for themselves and if it is offered in a dialogical format which recognises the students, their attempts, their identities, and their knowledge. The research question of this study, ‘How do experiences of forms of feedback affect female undergraduate student teachers’ chances of epistemic access?’, is not unusual. There have been many research projects that have been carried out that examine students’ experiences of feedback (for example, Evans, 2013; Basey, Maines, & Francis, 2014; Nicol et al.; 2014; Carless, 2019; Winstone et al., 2021). But I identified a gap where feedback has not, to my knowledge, been studied directly through the lenses of Epistemic Justice towards Parity of Participation. This study interpreted five undergraduate student teachers’ feedback experiences through these lenses. Narrative inquiry enabled me to design this study in ways that foregrounded experience. Data was collected through multiple conversations during which I organised the participants’ life stories of feedback within the dimensions of temporality, place and context, and sociality. Miranda Fricker’s (2007) theory of Epistemic Justice and Fraser’s norm of Parity of Participation (2000) framed this study. I engaged with Fricker and Fraser’s literature meaningfully as a reader and researcher. I established an understanding of how the lenses offered by Fraser and Fricker allowed me to make sense of the literature more generally, in social life and on the pedagogic practice of feedback. Fricker’s theory of Epistemic Justice considers the epistemically unjust, gendered, raced and classed, experiences of epistemic agents. Fricker (2007) draws on two central concepts to account for epistemic injustices: Testimonial Injustice and Hermeneutical Injustice. Fricker (2007; 2003) explains that testimonial injustice occurs within a testimonial exchange setting, when an epistemic agent as a speaker gives testimony of the epistemic agent’s experiences and knowledge but is not awarded the credibility the speaker deserves (Fricker, 2003). Epistemic agents who participate in a testimonial exchange need to overcome bias and prejudice in order to evaluate testimonies with the degree of fairness the testimony deserves (Fricker, 2013; 2016). Hermeneutical injustice occurs when an epistemic agent is unable to make sense and make meaning of their social experiences. Hermeneutical injustice strengthens when the epistemic agent is prevented from gaining access to resources that might help with sense making and meaning making of these social experiences (Dielman, 2012; Fricker, 2016). To ensure that meaning can be made between people and groups of people, there needs to be some shared understandings of the purpose and process of sense making and meaning-making – or a willingness to co-create such shared understandings. Fraser’s norm of Participatory Parity enabled a consideration of the larger world of political and economic systems that give rise to social injustice. In this study, the theories of Fricker and Fraser are used to illuminate experiences of feedback of the five undergraduate student teachers who are the participants in this study and how these translate to epistemic and social injustice. The norm of Participatory Parity is considered where feedback allowed or restricted participants from participating on an equal footing in the feedback process. Narrative inquiry, a research methodology that is used to study experiences, was used to inform research strategies of this study. Participants’ experiences, data collection and organising the narratives demonstrated the dimensions of temporality and space. The thesis includes biographical vignettes for each of the participants in the study, interspersed with data from across all five participants. The key findings of this study show that feedback generally operates at the surface levels of grammar correction. In light of the theoretical lenses of this study, I argue that the feedback experiences they shared generally did not recognise their attempts and the identities and knowledges they brought to the tasks. Because the focus was on superficial correction of the specific task, the feedback failed to create conditions for the (re)distribution of knowledge. At times the feedback exerted power on participants. Because the feedback was generally in the form of one directional correction (with little space for interaction with the feedback or dialogue with the assessor), this caused status subordination of participants in the epistemic spaces of teaching practice. Lastly, the lack of clarity of feedback was harmful to the potential for dialogical feedback. Such feedback caused participants to experience forms of epistemic injustice in the form of hermeneutical injustice where it failed to create conditions for the distribution of knowledge. Feedback also caused participants to experience testimonial injustice where it failed to create conditions for recognising participants’ processes of sense-making and meaning-making in the various assignment tasks. Participatory Parity could not occur because the processes of recognition and redistribution were constrained. Feedback then created fertile conditions of epistemic injustice to occur, and participants were likely to have failed to gain the much needed epistemic access. This study is not the story of bad, uncaring academics; the study acknowledges the context of large classes and heavy workloads in which feedback is or is not given. Rather, this is the story of five women trying to make their way through the university and out into the world as teachers. The study calls for better theorising of feedback and more support for both academics and students to develop feedback literacy so that feedback might serve as a dialogical pedagogic practice that enables epistemic justice. , Thesis (PhD) -- Faculty of Education, Centre for Higher Education Research, Teaching and Learning, 2022
- Full Text:
- Date Issued: 2022-04-08
An investigation of how a visual teaching approach can possibly address issues of mathematics anxiety at a selected school in the Oshikoto region of Namibia
- Ngonga, Daniel Nghifikepunye
- Authors: Ngonga, Daniel Nghifikepunye
- Date: 2022-04-08
- Subjects: Visual learning Namibia , Math anxiety Namibia , Mathematics Study and teaching Namibia , After-school programs Namibia , Mathematics Study and teaching Activity programs
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290637 , vital:56770
- Description: This Namibian case study aimed to explore a visual teaching approach (VTA) used by three selected teachers to address issues of mathematics anxiety (MA). The three teachers took part in an intervention program that was looking at how a VTA could be grown in the context of an after-school club (ASC) at my school. The selected teachers were the senior primary teachers at my school. The focus of the research was on how they taught mathematics using visuals after participating in an intervention programme. Their VTA made use of manipulatives, visuals, and concrete materials. The learners of the participating teachers completed a big MA pre-test, small MA tests, and a big MA post-test to determine their levels of MA as the teaching programme unfolded. The study hoped to create awareness amongst teachers and education researchers about the significant use of a VTA in the teaching and learning of mathematics to address issues of MA among the learners. It aimed to answer three research questions. One was on teachers’ use of a VTA in the context of an ASC; the second one was on comparisons of learners’ MA big pre and post-tests to detect any change of MA, and the last was on the enabling and constraining factors encountered when using a VTA. The main argument was that a VTA can encourage learners to be more confident and less anxious about doing mathematics. This study was framed by a constructivist perspective and its design and methodology were underpinned by an interpretive paradigm. This mixed-method research study employed video-recorded observations and stimulated recall interviews, learners’ MA test results, and the teachers’ focus group interviews as the means of collecting data. To generate rich data and support validity, four lessons per selected teacher were observed and video recorded; 54 learners completed the MA tests of 16 questions, and three teachers answered seven questions each in the focus group interview (FGI) after the stimulus recall interviews (SRI) which were done immediately after the lesson presentations. The study found that the participating teachers incorporated a variety of visuals into their lessons to make the mathematics fun, inspiring, visible, hands-on, and activity-oriented. They engaged the learners and also found that the use of visuals motivated learners and reduced their MA. , Thesis (MED) -- Faculty of Education, Education, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Ngonga, Daniel Nghifikepunye
- Date: 2022-04-08
- Subjects: Visual learning Namibia , Math anxiety Namibia , Mathematics Study and teaching Namibia , After-school programs Namibia , Mathematics Study and teaching Activity programs
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/290637 , vital:56770
- Description: This Namibian case study aimed to explore a visual teaching approach (VTA) used by three selected teachers to address issues of mathematics anxiety (MA). The three teachers took part in an intervention program that was looking at how a VTA could be grown in the context of an after-school club (ASC) at my school. The selected teachers were the senior primary teachers at my school. The focus of the research was on how they taught mathematics using visuals after participating in an intervention programme. Their VTA made use of manipulatives, visuals, and concrete materials. The learners of the participating teachers completed a big MA pre-test, small MA tests, and a big MA post-test to determine their levels of MA as the teaching programme unfolded. The study hoped to create awareness amongst teachers and education researchers about the significant use of a VTA in the teaching and learning of mathematics to address issues of MA among the learners. It aimed to answer three research questions. One was on teachers’ use of a VTA in the context of an ASC; the second one was on comparisons of learners’ MA big pre and post-tests to detect any change of MA, and the last was on the enabling and constraining factors encountered when using a VTA. The main argument was that a VTA can encourage learners to be more confident and less anxious about doing mathematics. This study was framed by a constructivist perspective and its design and methodology were underpinned by an interpretive paradigm. This mixed-method research study employed video-recorded observations and stimulated recall interviews, learners’ MA test results, and the teachers’ focus group interviews as the means of collecting data. To generate rich data and support validity, four lessons per selected teacher were observed and video recorded; 54 learners completed the MA tests of 16 questions, and three teachers answered seven questions each in the focus group interview (FGI) after the stimulus recall interviews (SRI) which were done immediately after the lesson presentations. The study found that the participating teachers incorporated a variety of visuals into their lessons to make the mathematics fun, inspiring, visible, hands-on, and activity-oriented. They engaged the learners and also found that the use of visuals motivated learners and reduced their MA. , Thesis (MED) -- Faculty of Education, Education, 2022
- Full Text:
- Date Issued: 2022-04-08
Chinese character learning with the aid of an ICT website among Mandarin Second Additional Language learners in South Africa: a case study
- Authors: Fu, Shuying
- Date: 2022-04-08
- Subjects: Mandarin dialects Study and teaching (Secondary) South Africa , Mandarin dialects Computer-assisted instruction for English speakers , Second language acquisition , Chinese characters , Information technology South Africa , Educational technology South Africa , Arch Chinese
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/263590 , vital:53641
- Description: The teaching of Mandarin as a Second Additional Language (SAL) in South African schools was only introduced in 2016. The year 2018 saw the first Mandarin as SAL National Senior Certificate examination. Little research has been done on the teaching and learning of Mandarin as a SAL subject at the high school level in South Africa. Character learning and teaching are some of the most challenging aspects of this language teaching and learning. This research sought to investigate how beginner Mandarin SAL learners can be supported by a particular Information Communication Technology (ICT) website, www.archchinese.com (Arch Chinese), in their character learning. Learners’ ability to memorise Chinese characters is of utmost importance for their success in this language learning, especially for matriculants. To support the main research goal, this study set out to investigate the requirements for Chinese character learning, the role the website Arch Chinese plays in learners’ character learning and Mandarin SAL learners’ experience of using Arch Chinese as a learning tool. This research was conducted in the form of a case study within the interpretative paradigm. It adopted a questionnaire and document analysis for data collection to gain insight into the research topic. To get answers to the research questions posed above, the study analysed the Curriculum Assessment Policy Statement (CAPS) Mandarin SAL documents from Grade 4–12, the Independent Examination Board (IEB) Mandarin Subject Assessment Guidelines (SAGs), and a textbook for beginners, Learn Chinese with me: Student’s book 1 in relation to character learning. The features and functions of the website, Arch Chinese, were also evaluated and Mandarin SAL learners’ answers to a questionnaire on their use of the website Arch Chinese were analysed. The study found that character teaching and learning has not been given enough attention in the curriculum. It was only covered in the Intermediate Phase but was seldom mentioned in the Senior and Further Education and Training Phases in the curriculum. The CAPS Mandarin SAL documents do not consider the special characteristics of the Mandarin language, as this curriculum was based on the CAPS English Generic SAL document. As a result, the assessment requirements on writing (character count requirement in particular) were not realistic. The teaching approaches promoted in the curriculum and the teaching time do not correspond well with the teaching and learning of this language. Moreover, this study found that there was no vocabulary list prescribed in the curriculum and therefore a gap exists between the curriculum on paper and the curriculum in practice. The analysis of the IEB SAGs found that the assessments were suitable for the level of Mandarin SAL learners. This is because the IEB considered the characteristics of the Mandarin language, which is non-cognate, to the alphabet-based languages that respondents in this research spoke or were familiar with. At the same time, the analysis of the website and the learners’ questionnaire found that learners held a positive attitude towards their use of the website and that it proved to help facilitate Mandarin SAL learners in their character learning. This study ends with recommendations for teachers, policy makers, the IEB, and character-learning websites. , Thesis (MEd) -- Faculty of Education, Education, 2022
- Full Text: false
- Date Issued: 2022-04-08
- Authors: Fu, Shuying
- Date: 2022-04-08
- Subjects: Mandarin dialects Study and teaching (Secondary) South Africa , Mandarin dialects Computer-assisted instruction for English speakers , Second language acquisition , Chinese characters , Information technology South Africa , Educational technology South Africa , Arch Chinese
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/263590 , vital:53641
- Description: The teaching of Mandarin as a Second Additional Language (SAL) in South African schools was only introduced in 2016. The year 2018 saw the first Mandarin as SAL National Senior Certificate examination. Little research has been done on the teaching and learning of Mandarin as a SAL subject at the high school level in South Africa. Character learning and teaching are some of the most challenging aspects of this language teaching and learning. This research sought to investigate how beginner Mandarin SAL learners can be supported by a particular Information Communication Technology (ICT) website, www.archchinese.com (Arch Chinese), in their character learning. Learners’ ability to memorise Chinese characters is of utmost importance for their success in this language learning, especially for matriculants. To support the main research goal, this study set out to investigate the requirements for Chinese character learning, the role the website Arch Chinese plays in learners’ character learning and Mandarin SAL learners’ experience of using Arch Chinese as a learning tool. This research was conducted in the form of a case study within the interpretative paradigm. It adopted a questionnaire and document analysis for data collection to gain insight into the research topic. To get answers to the research questions posed above, the study analysed the Curriculum Assessment Policy Statement (CAPS) Mandarin SAL documents from Grade 4–12, the Independent Examination Board (IEB) Mandarin Subject Assessment Guidelines (SAGs), and a textbook for beginners, Learn Chinese with me: Student’s book 1 in relation to character learning. The features and functions of the website, Arch Chinese, were also evaluated and Mandarin SAL learners’ answers to a questionnaire on their use of the website Arch Chinese were analysed. The study found that character teaching and learning has not been given enough attention in the curriculum. It was only covered in the Intermediate Phase but was seldom mentioned in the Senior and Further Education and Training Phases in the curriculum. The CAPS Mandarin SAL documents do not consider the special characteristics of the Mandarin language, as this curriculum was based on the CAPS English Generic SAL document. As a result, the assessment requirements on writing (character count requirement in particular) were not realistic. The teaching approaches promoted in the curriculum and the teaching time do not correspond well with the teaching and learning of this language. Moreover, this study found that there was no vocabulary list prescribed in the curriculum and therefore a gap exists between the curriculum on paper and the curriculum in practice. The analysis of the IEB SAGs found that the assessments were suitable for the level of Mandarin SAL learners. This is because the IEB considered the characteristics of the Mandarin language, which is non-cognate, to the alphabet-based languages that respondents in this research spoke or were familiar with. At the same time, the analysis of the website and the learners’ questionnaire found that learners held a positive attitude towards their use of the website and that it proved to help facilitate Mandarin SAL learners in their character learning. This study ends with recommendations for teachers, policy makers, the IEB, and character-learning websites. , Thesis (MEd) -- Faculty of Education, Education, 2022
- Full Text: false
- Date Issued: 2022-04-08
Computational analysis of known drug resistant mutants of Plasmodium falciparum Dihydrofolate Reductase (PfDHFR) and screening for novel antifolates against the enzyme
- Authors: Tata, Rolland Bantar
- Date: 2022-04-08
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/234184 , vital:50170
- Description: Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Tata, Rolland Bantar
- Date: 2022-04-08
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/234184 , vital:50170
- Description: Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-04-08
Demersal fish distribution in the shallow marine nearshore and estuarine seascape of Algoa Bay: Nursery areas and the effect of environmental drivers
- Authors: Nodo, Phakama
- Date: 2022-04-08
- Subjects: Groundfishes South Africa Algoa Bay , Estuarine fishes South Africa Algoa Bay , Marine nurseries South Africa Algoa Bay , Estuarine fishes Habitat South Africa Algoa Bay , Estuarine fishes Physiology South Africa Algoa Bay , Estuarine fishes Effect of pollution on South Africa Algoa Bay , Estuarine fishes Larvae South Africa Algoa Bay , Estuarine fishes Effect of human beings on South Africa Algoa Bay
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232399 , vital:49988 , DOI 10.21504/10962/232399
- Description: Estuaries and shallow marine nearshore areas are highly productive and valuable ecosystems, which provide numerous habitats for fish and support fundamental ecological links with other environments. Assessing fish distribution across estuarine and marine nearshore habitats is important to identify ecologically important habitats and develop effective management strategies for coastal fishes, many of which are important fishery species. Despite this, only a few studies have focussed on fish community patterns across an estuary and marine nearshore gradient concurrently, particularly including early life history stages, to determine the nursery value of both environments, and to examine whether these two coastal environments have distinct fish assemblages in relation to physical factors. The main aim of this study was to assess the environmental drivers of demersal fish communities in soft-bottom benthic habitats in two permanently open estuaries and adjacent marine nearshore areas (5 – 10 m) of Algoa Bay, South Africa, as well as to assess the relative roles of these two habitats as settlement and nursery areas for demersal fish species. A 1.5 m, conical shoeless beam trawl net was used to sample the demersal fish community concurrently in each habitat between July 2017 and September 2019. Sampling was conducted in July 2017, February, March, May, July, August, October and November 2019 and February, April and September 2019. DNA barcoding was used to verify identification of the early life history stages of fish caught in the estuarine and marine nearshore areas of Algoa Bay. In addition, since the two estuaries (Swartkops and Sundays) are heavily polluted, the effect of low dissolved oxygen and hypoxia and associated shifts in spatial distribution of demersal species was investigated. The two sampled estuaries had a higher abundance of demersal fishes, with a total of 6437 fishes (28 species) caught (3752 and 2685 individuals with 24 and 20 species recorded in the Sundays and Swartkops estuaries, respectively). Species richness was higher in the marine nearshore of Algoa Bay, with 29 species (797 individuals) caught. Of the 7234 individuals caught, the identification of 100 specimens, in either a larval or early juvenile phase, were uncertain and therefore DNA barcoding was used to verify their identification. Of these 100 individuals, 86 were positively identified to species level using COI sequences. Fourteen failed to amplify by PCR and could only be identified morphologically. The marine nearshore sites were dominated by species which spawn in the marine environment and are not dependent on estuaries (marine species and marine estuary-opportunists), whilst the estuaries were dominated by estuarine spawners or marine spawners dependent on estuaries to some degree. Two discrete demersal fish assemblages were identified representing the marine nearshore and the estuary, with no significant differences observed between the two estuaries (Sundays and Swartkops). The differences observed between the marine nearshore and estuary were mostly driven by salinity, turbidity, silt and organic content of the sediment. These distinct fish assemblages might be considered as indicators for the respective environments they inhabit. Both habitats were dominated by early life history stages (larvae to juveniles), indicating the nursery function of both habitats. Early life stages collectively comprised 97% of the catch in the marine nearshore and 68% in the estuary. Young-of-the-year (YOY) juveniles (< 1-year-old juveniles) and transformation stages (when changes in body shape and pigment pattern occur) dominated the total catch in the marine nearshore, while YOY juveniles dominated the estuarine fish assemblages. Ariidae Galeichthys feliceps, Haemulidae Pomadasys olivaceus, Sciaenidae Argyrosomus inodorus and Cynoglossidae Cynoglossus zanzibarensis, comprised the largest proportion of YOY juveniles in the marine nearshore. The transformation stage in the marine nearshore was numerically dominated by P. olivaceus and G. feliceps. In the estuarine environment, YOY juveniles were mostly dominated by Sparidae Rhabdosargus holubi, Soleidae Heteromycteris capensis and Gobiidae Caffrogobius gilchristi. The greatest abundance of early life stage fishes was observed in the lower reaches of the Sundays Estuary and the upper reaches of the Swartkops Estuary, as well as nearshore sites located in close proximity to the estuary mouths, particularly during spring and summer. Despite the fact that these coastal ecosystems are important nursery areas, they are threatened by a number of factors, including habitat loss and modification due to urban development, intensification of agriculture and subsequent eutrophication, climate change, and overfishing, all of which reduce ecosystem functioning and reduce the ecological and economic value of these habitats around the world. Hypoxia is one of the major threats to the functioning of coastal ecosystems, particularly estuaries. The Sundays and Swartkops estuaries both experience persistent eutrophic conditions, with frequent phytoplankton blooms (> 20 μg Chl-a l-1) that result in instances of bottom water oxygen depletion (< 4 mg/l). During the present study in the Sundays Estuary, low oxygen waters were recorded in the middle reaches (Site S5) mostly during summer (four months of low DO conditions). In the Swartkops Estuary, low dissolved oxygen was recorded in the upper reaches during spring. The lowest dissolved oxygen concentration recorded was 0.5 mg/l and 2.4 mg/l in the bottom waters of the Sundays and Swartkops estuaries, respectively. Selected dominant species were only absent from areas where dissolved oxygen was < 1 mg/l and present in the adjacent sites (for example Site S4, and S3) where DO was higher mostly during January 2019. As such, the low dissolved oxygen concentrations recorded in the Swartkops Estuary did not have a noticeable impact on fish distribution, although the total abundance of species did show a slight decline when dissolved oxygen was < 3 mg/l. This study demonstrates the importance of concurrently examining estuarine and nearshore marine habitats in order to identify ecologically important habitats, which has important implications for the development of effective management strategies for coastal fish populations, particularly in the light of anthropogenic change. In addition, in order to identify nursery hotspots it is crucial to correctly identify all the species occupying these areas. As such, this study confirms the importance of also using DNA barcoding for fish identification, particularly for the early life history stages of cryptic species (e.g. Argyrosomus inodorus and Argyrosomus japonicus). , Thesis (PhD) -- Faculty of Science, Ichthyology & Fisheries Sciences, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Nodo, Phakama
- Date: 2022-04-08
- Subjects: Groundfishes South Africa Algoa Bay , Estuarine fishes South Africa Algoa Bay , Marine nurseries South Africa Algoa Bay , Estuarine fishes Habitat South Africa Algoa Bay , Estuarine fishes Physiology South Africa Algoa Bay , Estuarine fishes Effect of pollution on South Africa Algoa Bay , Estuarine fishes Larvae South Africa Algoa Bay , Estuarine fishes Effect of human beings on South Africa Algoa Bay
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232399 , vital:49988 , DOI 10.21504/10962/232399
- Description: Estuaries and shallow marine nearshore areas are highly productive and valuable ecosystems, which provide numerous habitats for fish and support fundamental ecological links with other environments. Assessing fish distribution across estuarine and marine nearshore habitats is important to identify ecologically important habitats and develop effective management strategies for coastal fishes, many of which are important fishery species. Despite this, only a few studies have focussed on fish community patterns across an estuary and marine nearshore gradient concurrently, particularly including early life history stages, to determine the nursery value of both environments, and to examine whether these two coastal environments have distinct fish assemblages in relation to physical factors. The main aim of this study was to assess the environmental drivers of demersal fish communities in soft-bottom benthic habitats in two permanently open estuaries and adjacent marine nearshore areas (5 – 10 m) of Algoa Bay, South Africa, as well as to assess the relative roles of these two habitats as settlement and nursery areas for demersal fish species. A 1.5 m, conical shoeless beam trawl net was used to sample the demersal fish community concurrently in each habitat between July 2017 and September 2019. Sampling was conducted in July 2017, February, March, May, July, August, October and November 2019 and February, April and September 2019. DNA barcoding was used to verify identification of the early life history stages of fish caught in the estuarine and marine nearshore areas of Algoa Bay. In addition, since the two estuaries (Swartkops and Sundays) are heavily polluted, the effect of low dissolved oxygen and hypoxia and associated shifts in spatial distribution of demersal species was investigated. The two sampled estuaries had a higher abundance of demersal fishes, with a total of 6437 fishes (28 species) caught (3752 and 2685 individuals with 24 and 20 species recorded in the Sundays and Swartkops estuaries, respectively). Species richness was higher in the marine nearshore of Algoa Bay, with 29 species (797 individuals) caught. Of the 7234 individuals caught, the identification of 100 specimens, in either a larval or early juvenile phase, were uncertain and therefore DNA barcoding was used to verify their identification. Of these 100 individuals, 86 were positively identified to species level using COI sequences. Fourteen failed to amplify by PCR and could only be identified morphologically. The marine nearshore sites were dominated by species which spawn in the marine environment and are not dependent on estuaries (marine species and marine estuary-opportunists), whilst the estuaries were dominated by estuarine spawners or marine spawners dependent on estuaries to some degree. Two discrete demersal fish assemblages were identified representing the marine nearshore and the estuary, with no significant differences observed between the two estuaries (Sundays and Swartkops). The differences observed between the marine nearshore and estuary were mostly driven by salinity, turbidity, silt and organic content of the sediment. These distinct fish assemblages might be considered as indicators for the respective environments they inhabit. Both habitats were dominated by early life history stages (larvae to juveniles), indicating the nursery function of both habitats. Early life stages collectively comprised 97% of the catch in the marine nearshore and 68% in the estuary. Young-of-the-year (YOY) juveniles (< 1-year-old juveniles) and transformation stages (when changes in body shape and pigment pattern occur) dominated the total catch in the marine nearshore, while YOY juveniles dominated the estuarine fish assemblages. Ariidae Galeichthys feliceps, Haemulidae Pomadasys olivaceus, Sciaenidae Argyrosomus inodorus and Cynoglossidae Cynoglossus zanzibarensis, comprised the largest proportion of YOY juveniles in the marine nearshore. The transformation stage in the marine nearshore was numerically dominated by P. olivaceus and G. feliceps. In the estuarine environment, YOY juveniles were mostly dominated by Sparidae Rhabdosargus holubi, Soleidae Heteromycteris capensis and Gobiidae Caffrogobius gilchristi. The greatest abundance of early life stage fishes was observed in the lower reaches of the Sundays Estuary and the upper reaches of the Swartkops Estuary, as well as nearshore sites located in close proximity to the estuary mouths, particularly during spring and summer. Despite the fact that these coastal ecosystems are important nursery areas, they are threatened by a number of factors, including habitat loss and modification due to urban development, intensification of agriculture and subsequent eutrophication, climate change, and overfishing, all of which reduce ecosystem functioning and reduce the ecological and economic value of these habitats around the world. Hypoxia is one of the major threats to the functioning of coastal ecosystems, particularly estuaries. The Sundays and Swartkops estuaries both experience persistent eutrophic conditions, with frequent phytoplankton blooms (> 20 μg Chl-a l-1) that result in instances of bottom water oxygen depletion (< 4 mg/l). During the present study in the Sundays Estuary, low oxygen waters were recorded in the middle reaches (Site S5) mostly during summer (four months of low DO conditions). In the Swartkops Estuary, low dissolved oxygen was recorded in the upper reaches during spring. The lowest dissolved oxygen concentration recorded was 0.5 mg/l and 2.4 mg/l in the bottom waters of the Sundays and Swartkops estuaries, respectively. Selected dominant species were only absent from areas where dissolved oxygen was < 1 mg/l and present in the adjacent sites (for example Site S4, and S3) where DO was higher mostly during January 2019. As such, the low dissolved oxygen concentrations recorded in the Swartkops Estuary did not have a noticeable impact on fish distribution, although the total abundance of species did show a slight decline when dissolved oxygen was < 3 mg/l. This study demonstrates the importance of concurrently examining estuarine and nearshore marine habitats in order to identify ecologically important habitats, which has important implications for the development of effective management strategies for coastal fish populations, particularly in the light of anthropogenic change. In addition, in order to identify nursery hotspots it is crucial to correctly identify all the species occupying these areas. As such, this study confirms the importance of also using DNA barcoding for fish identification, particularly for the early life history stages of cryptic species (e.g. Argyrosomus inodorus and Argyrosomus japonicus). , Thesis (PhD) -- Faculty of Science, Ichthyology & Fisheries Sciences, 2022
- Full Text:
- Date Issued: 2022-04-08
Developing taxonomic and trait-based approaches for assessing and predicting macroinvertebrate responses to elevated fine sediments in the Tsitsa River and its tributaries, South Africa
- Authors: Ntloko, Pindiwe
- Date: 2022-04-08
- Subjects: Water quality South Africa Mzimvubu River Watershed , Sedimentation and deposition South Africa Mzimvubu River Watershed , Aquatic invertebrates Effect of sediments on South Africa Mzimvubu River Watershed , Aquatic invertebrates Classification , Environmental monitoring South Africa Mzimvubu River Watershed , Analysis of variance , Multivariate analysis
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/294692 , vital:57245 , DOI 10.21504/10962/294692
- Description: Sedimentation of freshwater systems is one of the leading causes of water quality deterioration. The Mzimvubu River catchment, which includes the Tsitsa River and its tributaries, in the Eastern Cape is prone to elevated sediment impact due to dispersive soils that are easily erodible. In this study, taxonomy and trait-based approaches were used to assess the responses of macroinvertebrates to fine sediments in the Tsitsa River and its tributaries. Macroinvertebrates and environmental variables were sampled seasonally in winter, spring, summer and autumn of 2016 to 2018 in six selected sites, using the South African Scoring System version 5 as a collecting protocol. The sites were selected to represent a decreasing gradient of sediment influence from the highly impacted Sites 1 (Tsitsa upstream) 2 (Tsitsa downstream), and 3 (Qurana River) to moderately impacted Sites 4 (Millstream upstream) and 5 (Millstream downstream) and the least impacted Sites 6 (Pot River upstream), 7 (Little Pot River) and 8 (Pot River downstream), which were collectively referred to as the control sites. Analysis of basic physico-chemical variables, dissolved oxygen, pH, electrical conductivity, turbidity, total suspended solids, temperature and nutrients were undertaken seasonally over the study period. Sediments grain sizes were also analysed. All collected data were subjected to appropriate statistical tests – univariate and multivariate techniques. A fine-sediment-specific multimetric index was developed to monitor the impact of fine sediments on macroinvertebrate assemblages of the Tsitsa River and its tributaries. A total of 12 traits, resolved into 48 trait attributes, were selected to explore their distribution in relation to a fine-sediment stress gradient, and identify the trait-based signature of fine-sediment impact. A trait-based approach was then developed to classify South African macroinvertebrates into two groups: taxa that are potentially vulnerable to fine-sediment impact and those potentially resilient, based on the combination of traits possessed. Two-way analysis of variance (ANOVA) indicated that electrical conductivity, turbidity, embeddedness and total suspended solids were statistically significantly different between the sites. Apart from Dissolved oxygen, the remaining variables were statistically significantly lower at the control sites (P < 0.05). The two-way multivariate analysis of variance (MANOVA) indicated global significant differences between sites and seasons. The two-way MANOVA also revealed that the interaction between the sites and seasons were statistically significant. The MANOVA indicated global combined interactive effects across the sites for suspended fine-sediment grain sizes, two-way ANOVA, followed by a Tukey’s post-hoc test, was carried out to indicate where the significant differences lay. The one-way ANOVA results indicated that very fine sand, very coarse silt, medium silt, and fine silt were significantly higher at Tsitsa upstream, Tsitsa downstream, Qurana tributary that is at Millstream upstream, Millstream downstream and Control sites. The rest of the grain sizes did not differ statistically between the sites. In terms of the settled sediment grain sizes, the volumetric analysis did not show considerable differences across the sites. Settled fine-sediment grain sizes were evenly distributed across the sites. Statistically, MANOVA results indicated no significant differences across sites or across seasons. The developed Sediment Multimetric Index indicated that the sites in the Tsitsa River and those in the Qurana River were highly sedimented during the wet season, but became moderately sedimented during the dry season, indicating that the index responded to seasonality. The sediment multimetric index indicated that the control sites were less sedimented during both the wet season and dry seasons, suggesting minimal seasonal effects at the control sites. Traits such as an exposed and soft body, collector-filterers, shredding, feeding on coarse particulate organic matter and a high sensitivity to dissolved oxygen were identified as fine- sediment-sensitive indicator traits. Identified fine-sediment-tolerant traits and ecological preferences included complete sclerotisation, a cased/tubed body, a preference for fine particulate organic matter, a high tolerance to dissolved oxygen depletion, and climbing and skating behaviours. Regarding the trait-based approach followed for classifying macroinvertebrates into vulnerable taxa and resilient taxa, the results revealed that the relative abundance and richness of the vulnerable taxa decreased predictably along the increasing gradient of sediment impact. However, the relative abundance and richness of resilient taxa showed no marked response to the impact of an increasing gradient of fine sediments. Overall, the present study makes a contribution to the complementary application of trait-and taxonomy-based approaches to freshwater biomonitoring. The trait-based approach enables predictions to be made and tested based on the mechanistic understanding of the mediating roles of traits in organism- environment interaction. A fundamental challenge, which showcases the limitation of the current study, is the sparse trait data on Afrotropical macroinvertebrates at the species or generic levels. In this regard, the iv trait-based approaches developed here were the family level instead of species or genus. This is the first study in South Africa to develop explicit trait-based indicators of elevated fine sediments as well as an approach for predicting macroinvertebrate vulnerability and resilience to fine-sediment effects, thus advancing the science and practice of freshwater biomonitoring. , Thesis (PhD) -- Faculty of Science, Institute for Water Research, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Ntloko, Pindiwe
- Date: 2022-04-08
- Subjects: Water quality South Africa Mzimvubu River Watershed , Sedimentation and deposition South Africa Mzimvubu River Watershed , Aquatic invertebrates Effect of sediments on South Africa Mzimvubu River Watershed , Aquatic invertebrates Classification , Environmental monitoring South Africa Mzimvubu River Watershed , Analysis of variance , Multivariate analysis
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/294692 , vital:57245 , DOI 10.21504/10962/294692
- Description: Sedimentation of freshwater systems is one of the leading causes of water quality deterioration. The Mzimvubu River catchment, which includes the Tsitsa River and its tributaries, in the Eastern Cape is prone to elevated sediment impact due to dispersive soils that are easily erodible. In this study, taxonomy and trait-based approaches were used to assess the responses of macroinvertebrates to fine sediments in the Tsitsa River and its tributaries. Macroinvertebrates and environmental variables were sampled seasonally in winter, spring, summer and autumn of 2016 to 2018 in six selected sites, using the South African Scoring System version 5 as a collecting protocol. The sites were selected to represent a decreasing gradient of sediment influence from the highly impacted Sites 1 (Tsitsa upstream) 2 (Tsitsa downstream), and 3 (Qurana River) to moderately impacted Sites 4 (Millstream upstream) and 5 (Millstream downstream) and the least impacted Sites 6 (Pot River upstream), 7 (Little Pot River) and 8 (Pot River downstream), which were collectively referred to as the control sites. Analysis of basic physico-chemical variables, dissolved oxygen, pH, electrical conductivity, turbidity, total suspended solids, temperature and nutrients were undertaken seasonally over the study period. Sediments grain sizes were also analysed. All collected data were subjected to appropriate statistical tests – univariate and multivariate techniques. A fine-sediment-specific multimetric index was developed to monitor the impact of fine sediments on macroinvertebrate assemblages of the Tsitsa River and its tributaries. A total of 12 traits, resolved into 48 trait attributes, were selected to explore their distribution in relation to a fine-sediment stress gradient, and identify the trait-based signature of fine-sediment impact. A trait-based approach was then developed to classify South African macroinvertebrates into two groups: taxa that are potentially vulnerable to fine-sediment impact and those potentially resilient, based on the combination of traits possessed. Two-way analysis of variance (ANOVA) indicated that electrical conductivity, turbidity, embeddedness and total suspended solids were statistically significantly different between the sites. Apart from Dissolved oxygen, the remaining variables were statistically significantly lower at the control sites (P < 0.05). The two-way multivariate analysis of variance (MANOVA) indicated global significant differences between sites and seasons. The two-way MANOVA also revealed that the interaction between the sites and seasons were statistically significant. The MANOVA indicated global combined interactive effects across the sites for suspended fine-sediment grain sizes, two-way ANOVA, followed by a Tukey’s post-hoc test, was carried out to indicate where the significant differences lay. The one-way ANOVA results indicated that very fine sand, very coarse silt, medium silt, and fine silt were significantly higher at Tsitsa upstream, Tsitsa downstream, Qurana tributary that is at Millstream upstream, Millstream downstream and Control sites. The rest of the grain sizes did not differ statistically between the sites. In terms of the settled sediment grain sizes, the volumetric analysis did not show considerable differences across the sites. Settled fine-sediment grain sizes were evenly distributed across the sites. Statistically, MANOVA results indicated no significant differences across sites or across seasons. The developed Sediment Multimetric Index indicated that the sites in the Tsitsa River and those in the Qurana River were highly sedimented during the wet season, but became moderately sedimented during the dry season, indicating that the index responded to seasonality. The sediment multimetric index indicated that the control sites were less sedimented during both the wet season and dry seasons, suggesting minimal seasonal effects at the control sites. Traits such as an exposed and soft body, collector-filterers, shredding, feeding on coarse particulate organic matter and a high sensitivity to dissolved oxygen were identified as fine- sediment-sensitive indicator traits. Identified fine-sediment-tolerant traits and ecological preferences included complete sclerotisation, a cased/tubed body, a preference for fine particulate organic matter, a high tolerance to dissolved oxygen depletion, and climbing and skating behaviours. Regarding the trait-based approach followed for classifying macroinvertebrates into vulnerable taxa and resilient taxa, the results revealed that the relative abundance and richness of the vulnerable taxa decreased predictably along the increasing gradient of sediment impact. However, the relative abundance and richness of resilient taxa showed no marked response to the impact of an increasing gradient of fine sediments. Overall, the present study makes a contribution to the complementary application of trait-and taxonomy-based approaches to freshwater biomonitoring. The trait-based approach enables predictions to be made and tested based on the mechanistic understanding of the mediating roles of traits in organism- environment interaction. A fundamental challenge, which showcases the limitation of the current study, is the sparse trait data on Afrotropical macroinvertebrates at the species or generic levels. In this regard, the iv trait-based approaches developed here were the family level instead of species or genus. This is the first study in South Africa to develop explicit trait-based indicators of elevated fine sediments as well as an approach for predicting macroinvertebrate vulnerability and resilience to fine-sediment effects, thus advancing the science and practice of freshwater biomonitoring. , Thesis (PhD) -- Faculty of Science, Institute for Water Research, 2022
- Full Text:
- Date Issued: 2022-04-08
Diversified computational approaches for the identification of orthosteric drugs, allosteric modulators and unveiling drug resistance mechanisms: application to infectious diseases
- Authors: Boateng, Rita Afriyie
- Date: 2022-04-08
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/234173 , vital:50169
- Description: Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Boateng, Rita Afriyie
- Date: 2022-04-08
- Subjects: Uncatalogued
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/234173 , vital:50169
- Description: Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-04-08
Dynamics of charge movement in ∞-Al2O3:C,Mg using thermoluminescence phototransferred and optically stimulated luminescence
- Authors: Lontsi Sob, Aaron Joel
- Date: 2022-04-08
- Subjects: Thermoluminescence , Optically stimulated luminescence , Phototransfer , Deep traps , Phototransferred thermoluminescence (PTTL)
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/294607 , vital:57237 , DOI 10.21504/10962/294607
- Description: The dosimetric features of ∞-Al2O3:C,Mg have been investigated for unannealed and annealed samples. The unannealed sample is referred to as sample A whereas the samples annealed at 700, 900 and 1200°C for 15 minutes each are referred to as samples B, C and D respectively. A glow curve of unannealed ∞-Al2O3:C,Mg measured at 1°C/s after irradiation to 2.0 Gy consists of peaks at 43, 73, 164, 195, 246, 284, 336 and 374°C respectively. For sample B (annealed at 700°C), a glow curve measured at 1°C/s after irradiation to 3.0 Gy has peaks at 46, 76, 100, 170, 199, 290, 330 and 375°C whereas the glow curve of sample C (annealed at 900°C) recorded under the same conditions consists of peaks at 49, 80, 100, 174, 206, 235, 290, 335 and 375°C respectively. Sample D (annealed at 1200°C) is the most sensitive of the four samples. A glow curve of sample D measured at 1°C/s after irradiation to 0.2 Gy has peaks at 52, 82, 102, 174, 234, 288 and 384°C respectively. The peaks are labelled I-VIII in order of appearance. The 100°C peak, labelled IIa, is induced by annealing at or above 700°C. The dose response of these peaks was studied for doses within 0.1-8.2 Gy. The reported peaks follow first-order kinetics irrespective of annealing temperature. Peaks I-III of each sample are reproduced under phototransfer for preheating up to 400°C. For the unannealed sample, the reproduced peaks are labelled A1-A3 whereas for the annealed samples, they are labelled B1-B3, C1-C3 and D1-D3 respectively. The annealing-induced peak at 100°C is reproduced as B2a, C2a and D2a for samples B, C and D respectively. A PTTL peak labelled C2b or D2b is also observed near 140°C in samples C and D. In addition to these PTTL peaks, a PTTL peak corresponding to peak IV is also found for sample D and for the unannealed sample. As the corresponding conventional peaks, the PTTL peaks of each sample follow first-order kinetics. Peak I and its corresponding PTTL peak for each sample are unstable and fade to a minimal level after 300 s of storage time. On the other hand, peak II of each sample and its corresponding PTTL peak could still be observed with delay up to 5000 s. Peak III of the unannealed sample remains stable with storage time up to 48 hours. Irrespective of annealing, the trap corresponding to peak III is the most sensitive to optical stimulation. Time-dependent profiles of PTTL from unannealed and annealed ∞-Al2O3:C,Mg were also studied. The mathematical analysis of the PTTL time-response profiles is based on experimental results. The role of various electron traps in PTTL was determined by using pulse annealing and by monitoring the dependence of peak intensity on duration of illumination for peaks not removed by preheating. The presence and role of deep traps were further demonstrated with thermally assisted optically stimulated luminescence. For the unannealed sample, the activation energy for thermal assistance is 0.033 ± 0.001 eV and the activation energy for thermal i quenching is 1.043 ± 0.001 eV. For sample C, the activation energy for thermal assistance is 0.044 ± 0.003 eV whereas that for thermal quenching is 1.110 ± 0.006 eV. The values for the activation energy for thermal assistance are lower than those reported in literature. Only the values for the activation energy for thermal quenching are somewhat comparable to values reported elsewhere. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Lontsi Sob, Aaron Joel
- Date: 2022-04-08
- Subjects: Thermoluminescence , Optically stimulated luminescence , Phototransfer , Deep traps , Phototransferred thermoluminescence (PTTL)
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/294607 , vital:57237 , DOI 10.21504/10962/294607
- Description: The dosimetric features of ∞-Al2O3:C,Mg have been investigated for unannealed and annealed samples. The unannealed sample is referred to as sample A whereas the samples annealed at 700, 900 and 1200°C for 15 minutes each are referred to as samples B, C and D respectively. A glow curve of unannealed ∞-Al2O3:C,Mg measured at 1°C/s after irradiation to 2.0 Gy consists of peaks at 43, 73, 164, 195, 246, 284, 336 and 374°C respectively. For sample B (annealed at 700°C), a glow curve measured at 1°C/s after irradiation to 3.0 Gy has peaks at 46, 76, 100, 170, 199, 290, 330 and 375°C whereas the glow curve of sample C (annealed at 900°C) recorded under the same conditions consists of peaks at 49, 80, 100, 174, 206, 235, 290, 335 and 375°C respectively. Sample D (annealed at 1200°C) is the most sensitive of the four samples. A glow curve of sample D measured at 1°C/s after irradiation to 0.2 Gy has peaks at 52, 82, 102, 174, 234, 288 and 384°C respectively. The peaks are labelled I-VIII in order of appearance. The 100°C peak, labelled IIa, is induced by annealing at or above 700°C. The dose response of these peaks was studied for doses within 0.1-8.2 Gy. The reported peaks follow first-order kinetics irrespective of annealing temperature. Peaks I-III of each sample are reproduced under phototransfer for preheating up to 400°C. For the unannealed sample, the reproduced peaks are labelled A1-A3 whereas for the annealed samples, they are labelled B1-B3, C1-C3 and D1-D3 respectively. The annealing-induced peak at 100°C is reproduced as B2a, C2a and D2a for samples B, C and D respectively. A PTTL peak labelled C2b or D2b is also observed near 140°C in samples C and D. In addition to these PTTL peaks, a PTTL peak corresponding to peak IV is also found for sample D and for the unannealed sample. As the corresponding conventional peaks, the PTTL peaks of each sample follow first-order kinetics. Peak I and its corresponding PTTL peak for each sample are unstable and fade to a minimal level after 300 s of storage time. On the other hand, peak II of each sample and its corresponding PTTL peak could still be observed with delay up to 5000 s. Peak III of the unannealed sample remains stable with storage time up to 48 hours. Irrespective of annealing, the trap corresponding to peak III is the most sensitive to optical stimulation. Time-dependent profiles of PTTL from unannealed and annealed ∞-Al2O3:C,Mg were also studied. The mathematical analysis of the PTTL time-response profiles is based on experimental results. The role of various electron traps in PTTL was determined by using pulse annealing and by monitoring the dependence of peak intensity on duration of illumination for peaks not removed by preheating. The presence and role of deep traps were further demonstrated with thermally assisted optically stimulated luminescence. For the unannealed sample, the activation energy for thermal assistance is 0.033 ± 0.001 eV and the activation energy for thermal i quenching is 1.043 ± 0.001 eV. For sample C, the activation energy for thermal assistance is 0.044 ± 0.003 eV whereas that for thermal quenching is 1.110 ± 0.006 eV. The values for the activation energy for thermal assistance are lower than those reported in literature. Only the values for the activation energy for thermal quenching are somewhat comparable to values reported elsewhere. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2022
- Full Text:
- Date Issued: 2022-04-08
Effect of adding a probiotic to an aquaponic system on plant and fish growth, water quality, and microbial diversity
- Authors: Kasozi, Nasser
- Date: 2022-04-08
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/294596 , vital:57236
- Description: Thesis embargoed. Release date April 2023. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Kasozi, Nasser
- Date: 2022-04-08
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/294596 , vital:57236
- Description: Thesis embargoed. Release date April 2023. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-04-08
English additional language student teachers’ development of oral strategic competence and confidence
- Authors: Meyers, Rozanne Elanore
- Date: 2022-04-08
- Subjects: Student teaching South Africa , Communicative competence South Africa , Oral communication , Native language and education , Language arts , Verbal ability , Multilingual education
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/263613 , vital:53643
- Description: This case study sought to understand how oral strategic and discourse competence and confidence developed in student teachers using English, their additional language, firstly as a tool of learning and secondly, as a medium of instruction in education environments. Within the broad qualitative approach an interpretive framework was adopted using multiple data collection tools. This was in order to privilege detailed accounts of participants’ experiences. Namely, unstructured interviews, drawings, observational checklists, and selfassessment questionnaires. Participants’ oral strategic and discourse competence were assessed using an observation checklist as they presented micro-teaching lessons. Additionally, participants completed a self-assessment questionnaire, reflecting on their oral competence after conducting their micro-teaching lessons. These perceptions were confirmed through a discussion of drawings that illustrated how they perceived themselves during lectures when they had to use English during oral interaction with lecturers and fellow students. Finally, unstructured interviews were conducted after participants completed their micro-teaching lessons and after participants had completed their drawings. The raw data from the four tools were analysed using a thematic approach. Main themes and categories were analysed and discussed to provide answers to the research questions. Data correlated the attitude of participants towards English and their level of oral confidence and competence. The main findings were that students were motivated to develop their oral English competence because they believed it was an important skill for teachers to possess. This motivation also proved to be a leading factor in participants’ competence despite the negative emotions they identified during spoken exchanges. Furthermore, the analysis found that collaborating with fellow students in making meaning of oral communication during lectures, increased students’ oral competence and their confidence because they were communicating in smaller groups. However, in certain situations, collaborating with students also decreased their confidence. Findings indicated that reciprocal facial expressions and the body language of those who engaged orally with the student teachers, increased their oral confidence as it served as an indication to them that they were understood. Based on these findings, recommendations are made regarding interactions during lectures for teacher training programmes in Higher Education in South Africa, for lecturers and lecturing practices, and curriculum designers in the South African Department of Education. , Thesis (MEd) -- Faculty of Education, Education, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Meyers, Rozanne Elanore
- Date: 2022-04-08
- Subjects: Student teaching South Africa , Communicative competence South Africa , Oral communication , Native language and education , Language arts , Verbal ability , Multilingual education
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/263613 , vital:53643
- Description: This case study sought to understand how oral strategic and discourse competence and confidence developed in student teachers using English, their additional language, firstly as a tool of learning and secondly, as a medium of instruction in education environments. Within the broad qualitative approach an interpretive framework was adopted using multiple data collection tools. This was in order to privilege detailed accounts of participants’ experiences. Namely, unstructured interviews, drawings, observational checklists, and selfassessment questionnaires. Participants’ oral strategic and discourse competence were assessed using an observation checklist as they presented micro-teaching lessons. Additionally, participants completed a self-assessment questionnaire, reflecting on their oral competence after conducting their micro-teaching lessons. These perceptions were confirmed through a discussion of drawings that illustrated how they perceived themselves during lectures when they had to use English during oral interaction with lecturers and fellow students. Finally, unstructured interviews were conducted after participants completed their micro-teaching lessons and after participants had completed their drawings. The raw data from the four tools were analysed using a thematic approach. Main themes and categories were analysed and discussed to provide answers to the research questions. Data correlated the attitude of participants towards English and their level of oral confidence and competence. The main findings were that students were motivated to develop their oral English competence because they believed it was an important skill for teachers to possess. This motivation also proved to be a leading factor in participants’ competence despite the negative emotions they identified during spoken exchanges. Furthermore, the analysis found that collaborating with fellow students in making meaning of oral communication during lectures, increased students’ oral competence and their confidence because they were communicating in smaller groups. However, in certain situations, collaborating with students also decreased their confidence. Findings indicated that reciprocal facial expressions and the body language of those who engaged orally with the student teachers, increased their oral confidence as it served as an indication to them that they were understood. Based on these findings, recommendations are made regarding interactions during lectures for teacher training programmes in Higher Education in South Africa, for lecturers and lecturing practices, and curriculum designers in the South African Department of Education. , Thesis (MEd) -- Faculty of Education, Education, 2022
- Full Text:
- Date Issued: 2022-04-08
Environmental governance, agency and multi-actor dynamics in Southern Africa
- Authors: Falayi, Menelisi
- Date: 2022-04-08
- Subjects: Environmental law South Africa , Environmental law Zimbabwe , Natural resources Management , Conservation of natural resources South Africa Eastern Cape , Natural resources Co-management South Africa Eastern Cape , Range policy South Africa Eastern Cape , Range management South Africa Eastern Cape , Forest reserves Law and legislation Zimbabwe , Agent (Philosophy)
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232355 , vital:49984 , DOI 10.21504/10962/232355
- Description: Natural resources have, since the beginning of time, played a central role in supporting human wellbeing. In southern Africa resource consumption has drastically increased over the past 50 years, resulting in biodiversity loss and land degradation. To reduce land degradation and biodiversity loss rates in the region, great emphasis has been placed on building effective governance structures that can deliver environmentally and socially sustainable outcomes. However, environmental governance continues to be a major challenge in the management and conservation of natural resources in the region. Thus, there is renewed scientific and policy interest in strengthening the capacity of governance systems. This thesis is timely; there is an increasing desire by policymakers and land users in the region to develop governance options that enhance multi-actor participation and collaboration. Therefore, this thesis explores the dynamics that influence the capacity of natural resource governance systems in southern Africa, predominately in Machubeni, South Africa (chapters 3 and 4) and in State forests in Zimbabwe (chapter 5). To achieve this aim, four stand-alone manuscripts that answer the following questions are included: 1. How have governance challenges manifested in natural resource management between 2010 and 2020 in southern Africa? 2. How were the governance objectives and attributes applied per historical period and what were the influencing drivers? a. What key drivers influenced rangeland condition over time in Machubeni? 3. How have multi-actor ties changed since the external investment in landscape governance and management in Machubeni, South Africa? 4. What role has agency played in the effectiveness of co-management initiatives in southern Africa? To answer the questions, I applied Bennett and Satterfield’s practical framework for understanding the objectives, attributes and elements of governance and Archer’s ii morphogenetic framework. The study employed a mixed-methods approach which included a scoping review methodology (chapter 2), household surveys, historical records, life history interviews, focus group discussions (chapters 3 and 4), social network analysis (chapter 4) and secondary data analysis (chapter 5). Results from the scoping review (chapter 2) show that research on governance challenges has not increased since 2010. Results suggest that governance challenges related to the maintenance of system integrity and functioning, specifically lack of coordination, accountability, skills, and resources to define effective natural resource management, were the most reported in the literature. Chapter 3 elucidates the importance of history in evaluating the application of governance objectives and rangeland condition in resource-poor areas. The results show that the residual impacts of the ‘ghost of environmental history’ still influence governance dynamics in Machubeni, South Africa. Furthermore, contemporary challenges are linked to history. Chapter 4 shows that transformative spaces enhance collaboration and knowledge sharing between land users, government, and researchers. Finally, chapter 5 employs the morphogenetic framework to assess how agency (the capacity of people and organisations to make choices and decisions about their lives) influenced the effectiveness of co-management initiatives in southern Africa. The results suggest that in attempts to shift governance towards greater effectiveness, more attention should be paid to building individual and group agency. Based on the results from the empirical chapters, the study identified three key focus areas that require more attention in order to build effective landscape governance and management in southern Africa:(i) acknowledging the role of historical legacies and context,(ii) building and developing agency, capacity and trust amongst actors and (iii) the development of sustainable landscape financing mechanisms that will enable governance systems to deliver socially and environmentally sustainable outcomes. , Ubutyebi bendalo buqhubekile budlala indima ebalulekileyo ekuxhaseni impilo-ntle yoluntu. Ngenxa yokubaluleka kobutyebi bendalo kubomi babantu, ukusetyenziswa kobutyebi kuye kwanda kakhulu kule minyaka eyi-50 idlulileyo, okubangela ulahleko lweentlobo-ntlobo yezityalo nezilwanyana eziphilayo kunye nokhukhuliseko komhlaba kumazantsi e-Afrika. Ukunciphisa ukhukhuliseko komhlaba kunye namazinga alahleko eentlobo-ntlobo zezityalo nezilwanyana eziphilayo kummandla, ugxininiso olukhulu luye lwabekwa ekwakhiweni kweziseko zolawulo ezisebenzayo ezinokuzisa iziphumo ezizinzileyo ngokwemeko yendalo nentlalo. Nangona kunjalo, ulawulo lwendalo lusaqhubeka lungumceli mngeni omkhulu kulawulo nolondolozo lobutyebi bendalo kulo mmandla. Ngoko ke, kukho umdla ohlaziyiweyo wenzululwazi nomgaqo-nkqubo ekomelezeni isakhono seenkqubo zolawulo. Le ithisisi ifike ngexesha kuba kukho umnqweno okhulayo kummandla ngabaqulunqi bomgaqo-nkqubo kunye nabasebenzisi bomhlaba ukuphuhlisa iinketho zolawulo eziphakamisa ukuthatha inxaxheba kwabantu abaninzi kunye nentsebenziswano. Ke ngoko, le ithisisi iphonononga izinto eziphembelela isakhono seenkqubo zolawulo lobutyebi bendalo kumazantsi eAfrika, ikakhulu eMachubeni, eMzantsi Afrika (isahluko 3 no 4) nakumahlathi kaRhulumente eZimbabwe (isahluko 5). Ukuphumeza le njongo, kufakwe layo: 1. Ibonakaliswe njani imiceli mngeni yolawulo kulawulo lwendalo phakathi ko-2010 no 2020 kumazantsi eAfrika? 2. Zeziphi injongo zolawulo kunye neempawu ezisetyenzisiweyo ngokwexesha lembali? a. Zeziphi ezona zinto eziqhuba phambili eziphembelele ukusetyenziswa kweenjongo zolawulo kunye neempawu ngokuhamba kwexesha? b. Zeziphi iindlela ezibalulekileyo ezichaphazele ngayo iimeko zamadlelo ekuhambeni kwexesha? 3. Atshintshe njani amakhonkco obudlelwane phakathi kwabathathi-nxaxheba ukusukela oko kutyalo-mali lwangaphandle kulawulo lobume bomhlaba eMachubeni, eMzantsi Afrika? 4. Yiyiphi indima edlalwe sisakhono sokwenza ukhetho kunye nezigqibo malunga nobomi bakho ekusebenzeni ngempumelelo kwamalinge olawulo ngokubambisana kumazantsi e-Afrika? Ukuphendula imibuzo, ndisebenzise isakhelo esisebenzayo sikaBennett kunye noSatterfield ukuqonda iinjongo kunye neempawu zolawulo kunye nesakhelo se-Archer's morphogenetic. Uphononongo lusebenzise iindlela ezixubeneyo ezibandakanya indlela yokuphonononga iincwadi zophando (isahluko 2), uphando lwamakhaya, iirekhodi zembali, udliwano-ndlebe lwembali yobomi, iingxoxo zeqela eligxininisiweyo (isahluko 3 kunye no 4), uhlalutyo lonxibelelwano nobudlelwane boluntu (isahluko 4) kunye nohlalutyo lwedatha ethathwe ngomnye umntu. (isahluko 5). Iziphumo ezivela kuphononongo lweencwadi zophando (isahluko 2) zibonakalisa ukuba uphando ngemiceli mngeni yolawulo alunyukanga ukusukela ngo-2010. Iziphumo zibonisa ukuba imiceli mngeni yolawulo enxulumene nokugcinwa kwemfezeko nokusebenza kwenkqubo, ngokukodwa ukungabikho kolungelelwaniso, uxanduva, izakhono, kunye nezibonelelo zokuchaza ulawulo lwemithombo yendalo olusebenzayo, yayiyeyona ichazwe kwiincwadi. Isahluko sesi-3 sicacisa ukubaluleka kwembali ekuvavanyeni ukusetyenziswa kweenjongo zolawulo kunye nemeko yemihlaba ekwiindawo ezihlwempuzekileyo ngezibonelelo. Iziphumo zibonisa ukuba uchaphazeleko oshiyekileyo we-‘ghost of environmental history’ zisenefuthe kulawulo lwenguquko eMachubeni, eMzantsi Afrika. Ngaphezu koko, imiceli mngeni yangoku inxulunyaniswa nembali. Isahluko sesi-4 sibonisa ukuba iindawo eziguqulayo ziphucula intsebenziswano nokwabelana ngolwazi phakathi kwabasebenzisi bomhlaba, urhulumente nabaphandi. Ekugqibeleni, isahluko sesi-5 sisebenzisa isakhelo se-morphogenetic ukuvavanya indlela isakhono sabantu kunye nemibutho sokwenza ukhetho kunye nezigqibo malunga nobomi babo ibe nefuthe ekusebenzeni kwamanyathelo olawulo ngokubambisana kumazantsi e-Afrika. Iziphumo zibonisa ukuba kwiinzame zokutshintsha ulawulo ukuze lusebenze kangangoko, ingqwalasela engaphezulu kufuneka ibekwe ekwakheni isakhono, somntu neseqela, sokwenza ukhetho kunye nezigqibo malunga nobomi babo. Ngokusekelwe kwiziphumo ezivela kwizahluko zobungqina, uphononongo luchonge imiba emithathu engundoqo ekugxilwe kuzo ezifuna ingqwalaselo ethe kratya ukuze kwakhiwe ulawulo lwemihlaba olusebenzayo kumazantsi e-Afrika. Ngokukodwa: (i) ukuqaphela indima yelifa lembali kunye nomxholo (ii) ukwakha nokuphuhlisa isakhono v sokwenza ukhetho kunye nezigqibo malunga nobomi, isakhono kunye nokuthembana phakathi kwabathathi-nxaxheba kunye (iii) nokuphuhliswa kweendlela ezizinzileyo zenkxaso-mali yendawo eziya kwenza ukuba iinkqubo zolawulo zinike iziphumo ezizinzileyo ngokwentlalo nendalo. , Thesis (PhD) -- Faculty of Science, Environmental Science, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Falayi, Menelisi
- Date: 2022-04-08
- Subjects: Environmental law South Africa , Environmental law Zimbabwe , Natural resources Management , Conservation of natural resources South Africa Eastern Cape , Natural resources Co-management South Africa Eastern Cape , Range policy South Africa Eastern Cape , Range management South Africa Eastern Cape , Forest reserves Law and legislation Zimbabwe , Agent (Philosophy)
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232355 , vital:49984 , DOI 10.21504/10962/232355
- Description: Natural resources have, since the beginning of time, played a central role in supporting human wellbeing. In southern Africa resource consumption has drastically increased over the past 50 years, resulting in biodiversity loss and land degradation. To reduce land degradation and biodiversity loss rates in the region, great emphasis has been placed on building effective governance structures that can deliver environmentally and socially sustainable outcomes. However, environmental governance continues to be a major challenge in the management and conservation of natural resources in the region. Thus, there is renewed scientific and policy interest in strengthening the capacity of governance systems. This thesis is timely; there is an increasing desire by policymakers and land users in the region to develop governance options that enhance multi-actor participation and collaboration. Therefore, this thesis explores the dynamics that influence the capacity of natural resource governance systems in southern Africa, predominately in Machubeni, South Africa (chapters 3 and 4) and in State forests in Zimbabwe (chapter 5). To achieve this aim, four stand-alone manuscripts that answer the following questions are included: 1. How have governance challenges manifested in natural resource management between 2010 and 2020 in southern Africa? 2. How were the governance objectives and attributes applied per historical period and what were the influencing drivers? a. What key drivers influenced rangeland condition over time in Machubeni? 3. How have multi-actor ties changed since the external investment in landscape governance and management in Machubeni, South Africa? 4. What role has agency played in the effectiveness of co-management initiatives in southern Africa? To answer the questions, I applied Bennett and Satterfield’s practical framework for understanding the objectives, attributes and elements of governance and Archer’s ii morphogenetic framework. The study employed a mixed-methods approach which included a scoping review methodology (chapter 2), household surveys, historical records, life history interviews, focus group discussions (chapters 3 and 4), social network analysis (chapter 4) and secondary data analysis (chapter 5). Results from the scoping review (chapter 2) show that research on governance challenges has not increased since 2010. Results suggest that governance challenges related to the maintenance of system integrity and functioning, specifically lack of coordination, accountability, skills, and resources to define effective natural resource management, were the most reported in the literature. Chapter 3 elucidates the importance of history in evaluating the application of governance objectives and rangeland condition in resource-poor areas. The results show that the residual impacts of the ‘ghost of environmental history’ still influence governance dynamics in Machubeni, South Africa. Furthermore, contemporary challenges are linked to history. Chapter 4 shows that transformative spaces enhance collaboration and knowledge sharing between land users, government, and researchers. Finally, chapter 5 employs the morphogenetic framework to assess how agency (the capacity of people and organisations to make choices and decisions about their lives) influenced the effectiveness of co-management initiatives in southern Africa. The results suggest that in attempts to shift governance towards greater effectiveness, more attention should be paid to building individual and group agency. Based on the results from the empirical chapters, the study identified three key focus areas that require more attention in order to build effective landscape governance and management in southern Africa:(i) acknowledging the role of historical legacies and context,(ii) building and developing agency, capacity and trust amongst actors and (iii) the development of sustainable landscape financing mechanisms that will enable governance systems to deliver socially and environmentally sustainable outcomes. , Ubutyebi bendalo buqhubekile budlala indima ebalulekileyo ekuxhaseni impilo-ntle yoluntu. Ngenxa yokubaluleka kobutyebi bendalo kubomi babantu, ukusetyenziswa kobutyebi kuye kwanda kakhulu kule minyaka eyi-50 idlulileyo, okubangela ulahleko lweentlobo-ntlobo yezityalo nezilwanyana eziphilayo kunye nokhukhuliseko komhlaba kumazantsi e-Afrika. Ukunciphisa ukhukhuliseko komhlaba kunye namazinga alahleko eentlobo-ntlobo zezityalo nezilwanyana eziphilayo kummandla, ugxininiso olukhulu luye lwabekwa ekwakhiweni kweziseko zolawulo ezisebenzayo ezinokuzisa iziphumo ezizinzileyo ngokwemeko yendalo nentlalo. Nangona kunjalo, ulawulo lwendalo lusaqhubeka lungumceli mngeni omkhulu kulawulo nolondolozo lobutyebi bendalo kulo mmandla. Ngoko ke, kukho umdla ohlaziyiweyo wenzululwazi nomgaqo-nkqubo ekomelezeni isakhono seenkqubo zolawulo. Le ithisisi ifike ngexesha kuba kukho umnqweno okhulayo kummandla ngabaqulunqi bomgaqo-nkqubo kunye nabasebenzisi bomhlaba ukuphuhlisa iinketho zolawulo eziphakamisa ukuthatha inxaxheba kwabantu abaninzi kunye nentsebenziswano. Ke ngoko, le ithisisi iphonononga izinto eziphembelela isakhono seenkqubo zolawulo lobutyebi bendalo kumazantsi eAfrika, ikakhulu eMachubeni, eMzantsi Afrika (isahluko 3 no 4) nakumahlathi kaRhulumente eZimbabwe (isahluko 5). Ukuphumeza le njongo, kufakwe layo: 1. Ibonakaliswe njani imiceli mngeni yolawulo kulawulo lwendalo phakathi ko-2010 no 2020 kumazantsi eAfrika? 2. Zeziphi injongo zolawulo kunye neempawu ezisetyenzisiweyo ngokwexesha lembali? a. Zeziphi ezona zinto eziqhuba phambili eziphembelele ukusetyenziswa kweenjongo zolawulo kunye neempawu ngokuhamba kwexesha? b. Zeziphi iindlela ezibalulekileyo ezichaphazele ngayo iimeko zamadlelo ekuhambeni kwexesha? 3. Atshintshe njani amakhonkco obudlelwane phakathi kwabathathi-nxaxheba ukusukela oko kutyalo-mali lwangaphandle kulawulo lobume bomhlaba eMachubeni, eMzantsi Afrika? 4. Yiyiphi indima edlalwe sisakhono sokwenza ukhetho kunye nezigqibo malunga nobomi bakho ekusebenzeni ngempumelelo kwamalinge olawulo ngokubambisana kumazantsi e-Afrika? Ukuphendula imibuzo, ndisebenzise isakhelo esisebenzayo sikaBennett kunye noSatterfield ukuqonda iinjongo kunye neempawu zolawulo kunye nesakhelo se-Archer's morphogenetic. Uphononongo lusebenzise iindlela ezixubeneyo ezibandakanya indlela yokuphonononga iincwadi zophando (isahluko 2), uphando lwamakhaya, iirekhodi zembali, udliwano-ndlebe lwembali yobomi, iingxoxo zeqela eligxininisiweyo (isahluko 3 kunye no 4), uhlalutyo lonxibelelwano nobudlelwane boluntu (isahluko 4) kunye nohlalutyo lwedatha ethathwe ngomnye umntu. (isahluko 5). Iziphumo ezivela kuphononongo lweencwadi zophando (isahluko 2) zibonakalisa ukuba uphando ngemiceli mngeni yolawulo alunyukanga ukusukela ngo-2010. Iziphumo zibonisa ukuba imiceli mngeni yolawulo enxulumene nokugcinwa kwemfezeko nokusebenza kwenkqubo, ngokukodwa ukungabikho kolungelelwaniso, uxanduva, izakhono, kunye nezibonelelo zokuchaza ulawulo lwemithombo yendalo olusebenzayo, yayiyeyona ichazwe kwiincwadi. Isahluko sesi-3 sicacisa ukubaluleka kwembali ekuvavanyeni ukusetyenziswa kweenjongo zolawulo kunye nemeko yemihlaba ekwiindawo ezihlwempuzekileyo ngezibonelelo. Iziphumo zibonisa ukuba uchaphazeleko oshiyekileyo we-‘ghost of environmental history’ zisenefuthe kulawulo lwenguquko eMachubeni, eMzantsi Afrika. Ngaphezu koko, imiceli mngeni yangoku inxulunyaniswa nembali. Isahluko sesi-4 sibonisa ukuba iindawo eziguqulayo ziphucula intsebenziswano nokwabelana ngolwazi phakathi kwabasebenzisi bomhlaba, urhulumente nabaphandi. Ekugqibeleni, isahluko sesi-5 sisebenzisa isakhelo se-morphogenetic ukuvavanya indlela isakhono sabantu kunye nemibutho sokwenza ukhetho kunye nezigqibo malunga nobomi babo ibe nefuthe ekusebenzeni kwamanyathelo olawulo ngokubambisana kumazantsi e-Afrika. Iziphumo zibonisa ukuba kwiinzame zokutshintsha ulawulo ukuze lusebenze kangangoko, ingqwalasela engaphezulu kufuneka ibekwe ekwakheni isakhono, somntu neseqela, sokwenza ukhetho kunye nezigqibo malunga nobomi babo. Ngokusekelwe kwiziphumo ezivela kwizahluko zobungqina, uphononongo luchonge imiba emithathu engundoqo ekugxilwe kuzo ezifuna ingqwalaselo ethe kratya ukuze kwakhiwe ulawulo lwemihlaba olusebenzayo kumazantsi e-Afrika. Ngokukodwa: (i) ukuqaphela indima yelifa lembali kunye nomxholo (ii) ukwakha nokuphuhlisa isakhono v sokwenza ukhetho kunye nezigqibo malunga nobomi, isakhono kunye nokuthembana phakathi kwabathathi-nxaxheba kunye (iii) nokuphuhliswa kweendlela ezizinzileyo zenkxaso-mali yendawo eziya kwenza ukuba iinkqubo zolawulo zinike iziphumo ezizinzileyo ngokwentlalo nendalo. , Thesis (PhD) -- Faculty of Science, Environmental Science, 2022
- Full Text:
- Date Issued: 2022-04-08
Ethnobotany and conservation biology of Warburgia salutaris (G.Bertol.) Chiov., a threatened medicinal plant in southern Mozambique
- Authors: Senkoro, Annae Maria
- Date: 2022-04-08
- Subjects: Ethnobotany Mozambique , Conservation biology Mozambique , Canellaceae Habitat Mozambique , Canellaceae Genetics , Warburgia salutaris Habitat Mozambique , Warburgia salutaris Genetics , Endangered plants Mozambique , Biogeography Climatic factors Mozambique , Traditional medicine Mozambique , Traditional ecological knowledge Mozambique
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232967 , vital:50042 , DOI 10.21504/10962/232967
- Description: Warburgia salutaris, locally known as “chibaha” (Ronga, Tsonga), “isiBhaha” (Zulu) and “siBhaha” (Siswati), is one of the most highly-valued medicinal plant species in southern Africa. Its bark has long been employed to treat bacterial and fungal infections, and it is often a front line herbal treatment for malaria. The species is popular in rural and urban areas due to its lower price compared to commercial pharmaceuticals and because of its long-standing spiritual and symbolic significance. Consequently, W. salutaris is threatened in Malawi, South Africa and Swaziland and is believed to be extincted in the wild in Zimbabwe. In Mozambique, where the tree is confined to the southern part of the country, it is considered vulnerable due to high local demand and cross-border export. Although there is limited research, further work is urgently needed to provide the basis for options and strategies to achieve desired outcomes. This study aimed to explore different approaches for the conservation of W. salutaris in the Lebombo Mountains (LM), the Tembe River (TR) and the Futi Corridor (FC) areas, in southern Mozambique. For this, potential distribution, socio cultural factors that influenced sustainable management of the species, demography, harvest impact, genetic diversity and population differentiation were considered. The kuenm package in R, 2 846 occurrence and 11 environmental data were used to model the potential current and future distribution in 2050 and 2070 using four general circulation models (CESM1(BGC), ACCESS1.3, FIO-ESM and IPSL-CM5A-MR) under representative concentration pathways (RCPs) 4.5 and 8.5. The extent of occurrence (EOO) and habitat suitability (HS) were also determined. Stratified random semi-structured interviews with 182 heads of households were carried out to explore cultural and socio incentives of use, compared knowledge distribution, determine local management practices and explore local ecological knowledge related to the species in the three study areas. In addition, 17 focus group discussion were conducted to clarify issues raised during household interviews. One hundred and twenty four quadrants were used to determine the abundance and population structure. The Simpson index of dominance, permutation index and quotient between consecutive classes were used to assess population stability, and an eight point scale was used to evaluate the extent of bark damages. Genomic deoxyribonucleic acid (gDNA) (n=48) was used to assessed genetic diversity and population structure through the newly developed single sequence repeats (SSR) molecular markers. Model selected was statistical significant for prediction of potential distribution of W. salutaris in southern Mozambique (partial ROC =0.00, omission rate = 0.04 and delta AICc = 0.00). The current environmental conditions mostly explained by climatic predictor, indicated in general, the potential distribution on areas of occurrence observed during the field work in southern Mozambique. Future project suggested an increase of climatic suitable areas in all the general circulation models in both conservative and pessimistic climatic scenarios (RCPs 4.5 and 8.5, respectively) in 2050 and 2070, and consequently the increase of HS and the EOO. Results of this work suggests W. salutaris would not extinct at least in the coming 50 years due to climate change but other threats such as overexploitation of the species need to be addressed. With increase of climatic suitable areas, conservation and management of this species could focus on reintroduction and cultivation for recovery of the species, with the help of time. W. salutaris was used for medicinal purposes to treat 12 health problems, with the bark being the most commonly used part (92% of informants). Knowledge of the species uses differed significantly between the three study areas but not with respondent gender or age. Informants also mentioned a considerable number of alternative species of W. salutaris (37 species in LM, 33 species in TR and 17 species in FC). Local ecological knowledge on the ecological niche of the species also varied substantial in the three areas with both types of knowledge generally higher in the Tembe River area. Local management practises were revealed mostly on harvesting through vertical bark stripping cited by 100% of informants in TR, 61.6% FC and 51.7 LM (71% of all informants). Yet most (64.3% of all informants, corresponding to 98.4% in TR, 51.7% in Fc and 41.7% LM) used non-traditional harvesting tools (machete) bark removal. For sustainable use of the species, consideration should be given to combined conservation strategies such as the use of alternative species with the same application, substitution of bark by leaves, and increases in alternative sources of plant material through cultivation. The densities of alive stems were not statistically different in the three areas but was higher in LM (mean of 4500.3±9209.8 stems/ha). Equally the mean densities of recruits (diameter ≤2 cm) were not considerable different but was higher in the FC (3296.8±9116.7 stems/ha). The regression analyses for the three study area revealed negative slopes, indicating more recruits and fewer individuals in larger classes. The Simpson indexes of dominance, permutation indexes and quotients between the consecutive size classes suggested some levels of population instability in the three areas. Harvesting took place in the eight point scale, all size classes were harvested but preference was higher on intermediate (15.1-20 cm) or larger (>20 cm) size classes in all the study areas but gatherers avoided harvesting bark from recruits. Although the mean densities of harvested stem was not significant this work indicated higher levels of stem destruction in FC. Harvested dead stems ware significant in the three areas and FC had the higher of (39.5±85.9 stems/ha) compared to 7.6±19.1 and 2.1±4.3 in TR and LM, respectively. Equally, the density of physiologically stressed stems differed substantially in the three areas with higher in FC 20.5± 75.5 stems/ha compared to 18.7±82.9 stems/ha in TR and 3.8±11.8 stems/ha in LM. This results suggests implementation of protection measures such as the inclusion of the species in the national CITES list to regulated cross-border trade and strengthening of the law enforcement. Genetic diversity, structure and gene flow in the exiting populations of southern Mozambique revealed that despite fragmentation and overexploitation, this species maintains a relatively high level of genetic diversity supporting the existence of random mating. Two genetic groups were found corresponding to the northern (LM and TR) and southern (FC) areas. The study suggests that, if local extinctions occurred in Mozambique, the pepper-bark tree persisted in sufficient numbers to retain a large proportion of genetic diversity. Management plans should concentrate on maintaining this high level of genetic variability through both in and ex-situ conservation actions. , Thesis (PhD) -- Faculty of Science, Environmental Science, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Senkoro, Annae Maria
- Date: 2022-04-08
- Subjects: Ethnobotany Mozambique , Conservation biology Mozambique , Canellaceae Habitat Mozambique , Canellaceae Genetics , Warburgia salutaris Habitat Mozambique , Warburgia salutaris Genetics , Endangered plants Mozambique , Biogeography Climatic factors Mozambique , Traditional medicine Mozambique , Traditional ecological knowledge Mozambique
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232967 , vital:50042 , DOI 10.21504/10962/232967
- Description: Warburgia salutaris, locally known as “chibaha” (Ronga, Tsonga), “isiBhaha” (Zulu) and “siBhaha” (Siswati), is one of the most highly-valued medicinal plant species in southern Africa. Its bark has long been employed to treat bacterial and fungal infections, and it is often a front line herbal treatment for malaria. The species is popular in rural and urban areas due to its lower price compared to commercial pharmaceuticals and because of its long-standing spiritual and symbolic significance. Consequently, W. salutaris is threatened in Malawi, South Africa and Swaziland and is believed to be extincted in the wild in Zimbabwe. In Mozambique, where the tree is confined to the southern part of the country, it is considered vulnerable due to high local demand and cross-border export. Although there is limited research, further work is urgently needed to provide the basis for options and strategies to achieve desired outcomes. This study aimed to explore different approaches for the conservation of W. salutaris in the Lebombo Mountains (LM), the Tembe River (TR) and the Futi Corridor (FC) areas, in southern Mozambique. For this, potential distribution, socio cultural factors that influenced sustainable management of the species, demography, harvest impact, genetic diversity and population differentiation were considered. The kuenm package in R, 2 846 occurrence and 11 environmental data were used to model the potential current and future distribution in 2050 and 2070 using four general circulation models (CESM1(BGC), ACCESS1.3, FIO-ESM and IPSL-CM5A-MR) under representative concentration pathways (RCPs) 4.5 and 8.5. The extent of occurrence (EOO) and habitat suitability (HS) were also determined. Stratified random semi-structured interviews with 182 heads of households were carried out to explore cultural and socio incentives of use, compared knowledge distribution, determine local management practices and explore local ecological knowledge related to the species in the three study areas. In addition, 17 focus group discussion were conducted to clarify issues raised during household interviews. One hundred and twenty four quadrants were used to determine the abundance and population structure. The Simpson index of dominance, permutation index and quotient between consecutive classes were used to assess population stability, and an eight point scale was used to evaluate the extent of bark damages. Genomic deoxyribonucleic acid (gDNA) (n=48) was used to assessed genetic diversity and population structure through the newly developed single sequence repeats (SSR) molecular markers. Model selected was statistical significant for prediction of potential distribution of W. salutaris in southern Mozambique (partial ROC =0.00, omission rate = 0.04 and delta AICc = 0.00). The current environmental conditions mostly explained by climatic predictor, indicated in general, the potential distribution on areas of occurrence observed during the field work in southern Mozambique. Future project suggested an increase of climatic suitable areas in all the general circulation models in both conservative and pessimistic climatic scenarios (RCPs 4.5 and 8.5, respectively) in 2050 and 2070, and consequently the increase of HS and the EOO. Results of this work suggests W. salutaris would not extinct at least in the coming 50 years due to climate change but other threats such as overexploitation of the species need to be addressed. With increase of climatic suitable areas, conservation and management of this species could focus on reintroduction and cultivation for recovery of the species, with the help of time. W. salutaris was used for medicinal purposes to treat 12 health problems, with the bark being the most commonly used part (92% of informants). Knowledge of the species uses differed significantly between the three study areas but not with respondent gender or age. Informants also mentioned a considerable number of alternative species of W. salutaris (37 species in LM, 33 species in TR and 17 species in FC). Local ecological knowledge on the ecological niche of the species also varied substantial in the three areas with both types of knowledge generally higher in the Tembe River area. Local management practises were revealed mostly on harvesting through vertical bark stripping cited by 100% of informants in TR, 61.6% FC and 51.7 LM (71% of all informants). Yet most (64.3% of all informants, corresponding to 98.4% in TR, 51.7% in Fc and 41.7% LM) used non-traditional harvesting tools (machete) bark removal. For sustainable use of the species, consideration should be given to combined conservation strategies such as the use of alternative species with the same application, substitution of bark by leaves, and increases in alternative sources of plant material through cultivation. The densities of alive stems were not statistically different in the three areas but was higher in LM (mean of 4500.3±9209.8 stems/ha). Equally the mean densities of recruits (diameter ≤2 cm) were not considerable different but was higher in the FC (3296.8±9116.7 stems/ha). The regression analyses for the three study area revealed negative slopes, indicating more recruits and fewer individuals in larger classes. The Simpson indexes of dominance, permutation indexes and quotients between the consecutive size classes suggested some levels of population instability in the three areas. Harvesting took place in the eight point scale, all size classes were harvested but preference was higher on intermediate (15.1-20 cm) or larger (>20 cm) size classes in all the study areas but gatherers avoided harvesting bark from recruits. Although the mean densities of harvested stem was not significant this work indicated higher levels of stem destruction in FC. Harvested dead stems ware significant in the three areas and FC had the higher of (39.5±85.9 stems/ha) compared to 7.6±19.1 and 2.1±4.3 in TR and LM, respectively. Equally, the density of physiologically stressed stems differed substantially in the three areas with higher in FC 20.5± 75.5 stems/ha compared to 18.7±82.9 stems/ha in TR and 3.8±11.8 stems/ha in LM. This results suggests implementation of protection measures such as the inclusion of the species in the national CITES list to regulated cross-border trade and strengthening of the law enforcement. Genetic diversity, structure and gene flow in the exiting populations of southern Mozambique revealed that despite fragmentation and overexploitation, this species maintains a relatively high level of genetic diversity supporting the existence of random mating. Two genetic groups were found corresponding to the northern (LM and TR) and southern (FC) areas. The study suggests that, if local extinctions occurred in Mozambique, the pepper-bark tree persisted in sufficient numbers to retain a large proportion of genetic diversity. Management plans should concentrate on maintaining this high level of genetic variability through both in and ex-situ conservation actions. , Thesis (PhD) -- Faculty of Science, Environmental Science, 2022
- Full Text:
- Date Issued: 2022-04-08
Exploring learners’ engagement with literacy in a book club
- Authors: Jamieson, Vuyokazi
- Date: 2022-04-08
- Subjects: Book clubs (Discussion groups) South Africa Makhanda , Literacy South Africa Makhanda , High school students Books and reading South Africa Makhanda , Books and reading South Africa Makhanda , Reading, Psychology of , Service learning South Africa Makhanda , Critical realism
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/263601 , vital:53642
- Description: This study observes the literacy engagement of a group of learners enrolled in Grades 8–10 in Nombulelo High School, a poorly-resourced school in the city of Makhanda in the Eastern Cape, South Africa. The learners participated in a book club hosted and run by St Andrew’s College, a privileged independent school, as a community engagement initiative. The idea of extending literacy engagement and engagement with written texts beyond textbooks used in schools is critical for learners with ambitions to enter higher education. Studying at a university requires a lot of reading, and if reading has not been taken up as a practice that involves more than ‘text consulting’ (Geisler, 1994) students will be unlikely to read the number of texts required of them. Studies (see Geisler, 1994 for an overview) have shown how the literacy of the university is very different to school based literacies. The assumption behind the study on which this thesis reports is that engagement with fictional texts might promote reading and bring about understandings of this activity as enjoyable and not a task only associated with schooling. The study is underpinned by a critical realist philosophy which allowed for the identification of structures and mechanisms that led to the emergence of literacy events in learners’ lives and to their experiences and observations of those events. The study was guided by the following questions: How do learners from a poorly-resourced high school engage around fictional texts in the context of a book club? What enables or constrains this engagement? The study was impacted by the Covid-19 pandemic in that lockdown requirements meant that learners from St Andrew’s College could not participate in the book club as much as anticipated initially as they had been forced to return home to pursue online learning. Learners from Nombuelo High School were, however, granted access to College premises, where they met in the school library following strict Covid protocols. The study draws on in-depth interviews, observations and document analysis of five learners from Nombulelo High School who participated in the book club, as well as on book reviews they wrote for the book club website. The critical realist analysis allows for the identification of mechanisms in learners’ homes and communities that enable literacies, including those that are screen-based such as using a computer, mobile phones and other technologies. This study found evidence of challenges regarding school based texts, reading fictional texts and viewing it as an enrichment of the school project. Because of children were African the emergence of communal practices and story telling is woven throughout the results section. However, is an example of the complexity of social and economic challenges facing South African marginalised schools. , Thesis (MEd) -- Faculty of Education, Centre for Higher Education Research, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Jamieson, Vuyokazi
- Date: 2022-04-08
- Subjects: Book clubs (Discussion groups) South Africa Makhanda , Literacy South Africa Makhanda , High school students Books and reading South Africa Makhanda , Books and reading South Africa Makhanda , Reading, Psychology of , Service learning South Africa Makhanda , Critical realism
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/263601 , vital:53642
- Description: This study observes the literacy engagement of a group of learners enrolled in Grades 8–10 in Nombulelo High School, a poorly-resourced school in the city of Makhanda in the Eastern Cape, South Africa. The learners participated in a book club hosted and run by St Andrew’s College, a privileged independent school, as a community engagement initiative. The idea of extending literacy engagement and engagement with written texts beyond textbooks used in schools is critical for learners with ambitions to enter higher education. Studying at a university requires a lot of reading, and if reading has not been taken up as a practice that involves more than ‘text consulting’ (Geisler, 1994) students will be unlikely to read the number of texts required of them. Studies (see Geisler, 1994 for an overview) have shown how the literacy of the university is very different to school based literacies. The assumption behind the study on which this thesis reports is that engagement with fictional texts might promote reading and bring about understandings of this activity as enjoyable and not a task only associated with schooling. The study is underpinned by a critical realist philosophy which allowed for the identification of structures and mechanisms that led to the emergence of literacy events in learners’ lives and to their experiences and observations of those events. The study was guided by the following questions: How do learners from a poorly-resourced high school engage around fictional texts in the context of a book club? What enables or constrains this engagement? The study was impacted by the Covid-19 pandemic in that lockdown requirements meant that learners from St Andrew’s College could not participate in the book club as much as anticipated initially as they had been forced to return home to pursue online learning. Learners from Nombuelo High School were, however, granted access to College premises, where they met in the school library following strict Covid protocols. The study draws on in-depth interviews, observations and document analysis of five learners from Nombulelo High School who participated in the book club, as well as on book reviews they wrote for the book club website. The critical realist analysis allows for the identification of mechanisms in learners’ homes and communities that enable literacies, including those that are screen-based such as using a computer, mobile phones and other technologies. This study found evidence of challenges regarding school based texts, reading fictional texts and viewing it as an enrichment of the school project. Because of children were African the emergence of communal practices and story telling is woven throughout the results section. However, is an example of the complexity of social and economic challenges facing South African marginalised schools. , Thesis (MEd) -- Faculty of Education, Centre for Higher Education Research, 2022
- Full Text:
- Date Issued: 2022-04-08
Inhibition of aluminium corrosion using phthalocyanines: Experimental and computational studies
- Authors: Nnaji, Nnaemeka Joshua
- Date: 2022-04-08
- Subjects: Aluminum Corrosion , Electrochemistry , Phthalocyanines , Corrosion and anti-corrosives , Protective coatings , Density functionals
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/294643 , vital:57240 , DOI 10.21504/10962/294643
- Description: Metal deterioration over time is a process known as corrosion, an electrochemical process, which can occur by surface chemical actions on metals by its environment. Metal corrosion have great economic, security, and environmental consequences, and its control is a major research area in corrosion science. Amongst the different corrosion protecting approaches, the use of corrosion inhibitors and protective coatings have attracted enormous research interest in this area of scholasticism. This has necessitated the computational and electrochemical investigations of aluminium corrosion inhibitive potentials of some compounds in 1M HCl. Metal free (5_H2), ClGa(III) (5_Ga) and Co(II) (5_Co) tetrakis(4-acetamidophenoxy)phthalocyanines as well as Co(II) 2,9,16-tris(4-(tert-butyl)phenoxy)-23-(pyridin-4-yloxy)phthalocyanine (6) and Co(II) 2,9,16,24-tetrakis(4-(tert-butyl)phenoxy)phthalocyanine (7) were synthesized for the first time and studied for corrosion inhibition. The reported ClGa(III) tetrakis(benzo[d]thiazol-2-yl-thio)phthalocyaninine (1), ClGa(III) tetrakis(benzo[d]thiazol-2ylphenoxy)phthalocyanine (2), ClGa(III) tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyanine) (3) and ClGa(III) tetrakis-4,4′-((4-(benzo[d]thiazol-2-yl)-1,2-bis(phenoxy)-bis(phthalocyanine) (4) were also employed for corrosion inhibition of Al in HCl. Corrosion inhibition measurements using electrochemical techniques showed that increased π conjugation caused (1) to (2) to outperform (1a) and (2a) respectively as aluminium corrosion inhibitors in 1.0 M hydrochloric acid. For similar reason, (4) outperformed 2. (1) and (2) were successfully electrodeposited onto aluminium for corrosion retardation in 1.0 M hydrochloric acid solution. Measurements obtained from electrochemical impedance spectroscopy gave corrosion inhibition efficiency values of 82% for 1 and 86% for 2 in 1.0 M hydrochloric acid solution and showed that electrodeposited phthalocyanines have enhanced aluminium corrosion retardation than when in solution. The use of reduced graphene oxide nanosheets (rGONS) alone as aluminium corrosion inhibitor is discouraged because of poor aluminium corrosion inhibition in 1M HCl. However, synergistic effects were observed when rGONS was mixed each with (4) and (3). (5_H2), (5_Ga) and (5_Co) decreased aluminium corrosion in 1M HCl and observation was that the heavier the atom the more decreased the protection and the free base performed best of the three. Studied tertbutylphenoxy-derived CoPcs (6 and 7) exhibited good aluminium corrosion inhibition properties in studied acidic solution and the unsymmetric CoPc (6) which has more heteroatoms, gave better performance. Quantum chemical calculations involved the use of density functional theoretical (DFT) approaches and gave results which corroborated with experimental findings. , Thesis (PhD) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Nnaji, Nnaemeka Joshua
- Date: 2022-04-08
- Subjects: Aluminum Corrosion , Electrochemistry , Phthalocyanines , Corrosion and anti-corrosives , Protective coatings , Density functionals
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/294643 , vital:57240 , DOI 10.21504/10962/294643
- Description: Metal deterioration over time is a process known as corrosion, an electrochemical process, which can occur by surface chemical actions on metals by its environment. Metal corrosion have great economic, security, and environmental consequences, and its control is a major research area in corrosion science. Amongst the different corrosion protecting approaches, the use of corrosion inhibitors and protective coatings have attracted enormous research interest in this area of scholasticism. This has necessitated the computational and electrochemical investigations of aluminium corrosion inhibitive potentials of some compounds in 1M HCl. Metal free (5_H2), ClGa(III) (5_Ga) and Co(II) (5_Co) tetrakis(4-acetamidophenoxy)phthalocyanines as well as Co(II) 2,9,16-tris(4-(tert-butyl)phenoxy)-23-(pyridin-4-yloxy)phthalocyanine (6) and Co(II) 2,9,16,24-tetrakis(4-(tert-butyl)phenoxy)phthalocyanine (7) were synthesized for the first time and studied for corrosion inhibition. The reported ClGa(III) tetrakis(benzo[d]thiazol-2-yl-thio)phthalocyaninine (1), ClGa(III) tetrakis(benzo[d]thiazol-2ylphenoxy)phthalocyanine (2), ClGa(III) tetrakis-4-(hexadecane-1,2-dioxyl)-bis(phthalocyanine) (3) and ClGa(III) tetrakis-4,4′-((4-(benzo[d]thiazol-2-yl)-1,2-bis(phenoxy)-bis(phthalocyanine) (4) were also employed for corrosion inhibition of Al in HCl. Corrosion inhibition measurements using electrochemical techniques showed that increased π conjugation caused (1) to (2) to outperform (1a) and (2a) respectively as aluminium corrosion inhibitors in 1.0 M hydrochloric acid. For similar reason, (4) outperformed 2. (1) and (2) were successfully electrodeposited onto aluminium for corrosion retardation in 1.0 M hydrochloric acid solution. Measurements obtained from electrochemical impedance spectroscopy gave corrosion inhibition efficiency values of 82% for 1 and 86% for 2 in 1.0 M hydrochloric acid solution and showed that electrodeposited phthalocyanines have enhanced aluminium corrosion retardation than when in solution. The use of reduced graphene oxide nanosheets (rGONS) alone as aluminium corrosion inhibitor is discouraged because of poor aluminium corrosion inhibition in 1M HCl. However, synergistic effects were observed when rGONS was mixed each with (4) and (3). (5_H2), (5_Ga) and (5_Co) decreased aluminium corrosion in 1M HCl and observation was that the heavier the atom the more decreased the protection and the free base performed best of the three. Studied tertbutylphenoxy-derived CoPcs (6 and 7) exhibited good aluminium corrosion inhibition properties in studied acidic solution and the unsymmetric CoPc (6) which has more heteroatoms, gave better performance. Quantum chemical calculations involved the use of density functional theoretical (DFT) approaches and gave results which corroborated with experimental findings. , Thesis (PhD) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-04-08
Neutral winds and tides over South Africa
- Authors: Ojo, Taiwo Theophilus
- Date: 2022-04-08
- Subjects: Atmospheric tides , Ionosondes , Fabry-Perot interferometers , Thermospheric winds , Servomechanisms , Climatology , Neutral winds , Horizontal Wind Model (HWM)
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232459 , vital:49993 , DOI 10.21504/10962/232459
- Description: This thesis presents the first results of a climatology of nighttime thermospheric neutral winds between February 2018 and January 2019 measured by a Fabry-Perot interferometer (FPI) in Sutherland, South Africa (32.2°S, 20.48°E; geomagnetic latitude: 40.7°S). This FPI measures the nighttime oxygen airglow emission at 630.0 nm, which has a peak intensity at an altitude of roughly 250 km. The performance of the Horizontal Wind Model (HWM14) was evaluated by comparing results from HWM14 with the FPI measurements. The results showed that the model had a better agreement with the measurements for meridional component compared to the zonal component. In addition, the HWM14 zonal wind consistently peaked several hours (~3 h) prior to the measured wind, creating what looks like a phase shift compared to the measured wind. An investigation of this apparent phase shift revealed it to be a consequence of a difference in phase shift of the terdiunal tide. Since ionosondes are more prolific with wider temporal and spatial coverage than FPIs, nighttime meridional winds aligned to the magnetic meridian were inferred from the peak height (hmF2) of ionospheric data taken from South Africa ionosonde network using the servo model during February 2018-June 2019. These were compared with FPI measured meridional wind and benchmarked with HWM14 and Magnetic mEridional NeuTrAl Thermospheric (MENTAT) model. The amplitudes and trends of the calculated meridional winds across all four ionosonde stations agreed relatively well with the observed data, especially during the summer months. Furthermore, the results confirmed that the ionosonde station located closest to the FPI, i.e. Hermanus station, had better agreement with measurements compared to the stations located at further distances. The extraction and analysis of atmospheric tides, namely the diurnal, semidiurnal, terdiurnal and 6-hour components from the FPI as well as the long-term tidal winds variations from the thermospheric wind measurements were investigated. The results showed that the semidiurnal peak mostly had the highest peak across all the months, indicating that the semidiurnal tides dominate the dynamic structure of the upper mesosphere at midlatitudes, consistent with previous observation over midlatitudes. Futhermore, the signature of the diurnal tide in the meridional (zonal) wind was stronger in winter (summer) and weaker in summer (winter). Also, semidiurnal tide didn't show any trend with season, while the terdiurnal tide was dominant in summer (zonal) and winter (meridional). Lastly, the 6 hour tide was detected intermittently during the period of the study and had the weakest signature (i.e. lowest amplitudes). , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Ojo, Taiwo Theophilus
- Date: 2022-04-08
- Subjects: Atmospheric tides , Ionosondes , Fabry-Perot interferometers , Thermospheric winds , Servomechanisms , Climatology , Neutral winds , Horizontal Wind Model (HWM)
- Language: English
- Type: Doctoral thesis , text
- Identifier: http://hdl.handle.net/10962/232459 , vital:49993 , DOI 10.21504/10962/232459
- Description: This thesis presents the first results of a climatology of nighttime thermospheric neutral winds between February 2018 and January 2019 measured by a Fabry-Perot interferometer (FPI) in Sutherland, South Africa (32.2°S, 20.48°E; geomagnetic latitude: 40.7°S). This FPI measures the nighttime oxygen airglow emission at 630.0 nm, which has a peak intensity at an altitude of roughly 250 km. The performance of the Horizontal Wind Model (HWM14) was evaluated by comparing results from HWM14 with the FPI measurements. The results showed that the model had a better agreement with the measurements for meridional component compared to the zonal component. In addition, the HWM14 zonal wind consistently peaked several hours (~3 h) prior to the measured wind, creating what looks like a phase shift compared to the measured wind. An investigation of this apparent phase shift revealed it to be a consequence of a difference in phase shift of the terdiunal tide. Since ionosondes are more prolific with wider temporal and spatial coverage than FPIs, nighttime meridional winds aligned to the magnetic meridian were inferred from the peak height (hmF2) of ionospheric data taken from South Africa ionosonde network using the servo model during February 2018-June 2019. These were compared with FPI measured meridional wind and benchmarked with HWM14 and Magnetic mEridional NeuTrAl Thermospheric (MENTAT) model. The amplitudes and trends of the calculated meridional winds across all four ionosonde stations agreed relatively well with the observed data, especially during the summer months. Furthermore, the results confirmed that the ionosonde station located closest to the FPI, i.e. Hermanus station, had better agreement with measurements compared to the stations located at further distances. The extraction and analysis of atmospheric tides, namely the diurnal, semidiurnal, terdiurnal and 6-hour components from the FPI as well as the long-term tidal winds variations from the thermospheric wind measurements were investigated. The results showed that the semidiurnal peak mostly had the highest peak across all the months, indicating that the semidiurnal tides dominate the dynamic structure of the upper mesosphere at midlatitudes, consistent with previous observation over midlatitudes. Futhermore, the signature of the diurnal tide in the meridional (zonal) wind was stronger in winter (summer) and weaker in summer (winter). Also, semidiurnal tide didn't show any trend with season, while the terdiurnal tide was dominant in summer (zonal) and winter (meridional). Lastly, the 6 hour tide was detected intermittently during the period of the study and had the weakest signature (i.e. lowest amplitudes). , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2022
- Full Text:
- Date Issued: 2022-04-08
Quantifying the impacts of cactus biological control agents in South Africa
- Authors: Mnqeta, Zezethu
- Date: 2022-04-08
- Subjects: Cactus Biological control South Africa , Noxious weeds South Africa , Invasive plants Biological control South Africa , Insects as biological pest control agents South Africa , Cochineal insect South Africa , Mealybugs South Africa , Agricultural productivity South Africa
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/294631 , vital:57239 , DOI 10.21504/10962/294631
- Description: Invasive alien cacti are prominent weeds that threaten indigenous biodiversity and have a negative impact on agricultural productivity in South Africa. These plants are problematic because they form dense thickets that reduce the carrying capacity of rangelands; restrict the movement of livestock and wildlife thus reducing access to shade and water sources; and are directly harmful to livestock, wildlife and people due to their sharp spines. Biological control is the most effective, affordable and environmentally friendly method to control invasive alien cacti and minimize their negative impacts. Cochineal insects (Dactylopius spp.: Dactylopiidae) and the gall-forming mealybug, Hypogeococcus sp. (Pseudococcidae) are used as biological control agents for cacti. The agents are however poor dispersers, so mass-rearing and augmentative releases are required in order to establish the agents at sites where they are needed. This study aimed to evaluate the mass-rearing and release efforts of cactus biological control in South Africa, quantify the impact of the biological control agents on cactus plant populations through long-term monitoring, and assess the benefits accrued due to the biological control agents through the perceptions of land-users. An assessment of the effectiveness of the release effort for cactus biological control agents was conducted by comparing where biological control agents have been released with the known distribution of the target weeds. Only 26% of the quarter degree squares that are known to be occupied by invasive alien cacti have had biological control agents released in them. This indicated that the mass-rearing and release efforts in South Africa are inadequate and should be increased, especially in areas where few releases have been made and many cacti are present, such as the Limpopo Province. The impact of the biological control agents on cactus plant populations was assessed by monitoring agent densities, target plant densities and target plant reproductive outputs before and after releases. Plant biomass and reproductive output were reduced by biological control agents for three of the target weeds that were assessed, while the duration of the study was too short to measure reductions for the fourth target weed. Benefits to land-users were then quantified through a questionnaire survey. Land-users perceived biological control as an effective management option, with 81% of the land-users reporting that there was less invasive alien cactus after releasing biological control agents on their land. Forty-nine percent of the land-users believed that the negative impacts of the cactus had been reduced and that they benefited more from their land since control was achieved. Since land-users were only interviewed within four years of the releases being conducted, it is expected that the percentage of land-users who gained benefits from biological control will increase in future. Ninety-seven percent of the land-users stated that the agents were safe and had not fed on any other plants or had any detrimental impacts. These perceptions indicated that land-users regarded biological control as a safe and effective method of controlling invasive alien cacti. This study confirms that biological control is an effective and safe way of controlling invasive alien Cactaceae. It is also the first to assess some of the benefits that land-users have accrued due to biological control of cactus weeds. It is however evident that a greater mass-rearing and release effort is required for South Africa to get the maximum benefits possible from the use of the biological control agents for cactus weeds that are available in the country. , Izityalo ze-cactus ezisuka kwamanye amazwe zilukhula olubalaseleyo, olwenza ingxaki kwintlobo ngeentlobo zezityalo nezilwanyana kwaye ezizityalo zinefuthe neziphumo ezingalunganga kwimveliso yezolimo eMzantsi Afrika. Ezi zizityalo ziyingxaki kuba zenza amatyholo ashinyeneyo athi anciphise umthamo wokusebenzisa umhlaba: zinqanda ukuhamba nogkukhululekileyo kwemfuyo nezilwanyana zasendle ngokwenza oko zingakwazi ukufikelela emthuzini xa kutshisa nakwimithombo yamanzi yokusela; zikwayiyo nengozi kwimfuyo, izilwanyana zasendle kunye nabantu ngenxa yamave abukhali afumaneka kwezizityalo. Ukulawula nokwehliza ubunzini nezinga lemigcipheko yezizityalo, kusetyenziswa indlela ekuthiwa yi-biological control. Lendlela yeyona ndlela isebenza ngokuphucukileyo, efikelelayo, nengenabungozi kokusingqongileyo. Izinambuzane ze- cochineal (i-Dactylopius spp.: Dactylopiidae) kunye ne-mealybug, i-Hypogeococcus sp. (Pseudococcidae) zisetyenziswe njengezixhobo ze-biological control ezinceda ukulawula ezizityalo ze-cactus zingafunekiyo. Ingxaki yazo ezizinambuzane zizixhobo ze-biological control zingentla kukuba azikwazi kuzisasaza ngokwazo ukuba zifikelele nakwizityalo ezikude ngoko ke ukukhuliswa nokukhutshwa ngobuninzi bazo kuyafuneka ukukhawulelana nalengxaki kunye nokwandisa amathuba wokuba zifikelele kuzozonke izityalo ze-cactus ekufuneka zizilawule. Olu phononongo lujolise ekuvavanyeni iinzame zokukhulisa ngobuninzi nokukhupha ezezinambuzane zizixhobo ze-bioloigical control zokulawula izityalo ze-cactus eMzantsi Afrika, ukujonga ubungakanani befuthe notshintsho elenziwa zezinambuzane zizixhobo ze-bioloigical control kwizityalo ze-cactus emva kwexesha elide lokuzijonga, kunye nokuvavanya inzuzo efunyenwe ngenxa yokulawula ezizityalo ze-cactus ngokwemibono yabasebenzisi bomhlaba. Uvavanyo lweenzame zokukhutshwa kwezixhobo zezixhobo zezinambuzane ze-bioloigical control kwizityalo ze-cactus lwenziwa ngokuthelekisa iindawo apho izixhobo zezinambuzane ze-biological control zikhutshwe khona kunye neendawo apho izityalo ze-cactus kwaziwayo ukuba ziyafumaneka khona. Yi-26% kuphela yesikwere sekota eyaziwayo ukuba kukhona izityalo ze-cactus nalapho kukhutshwe khona kwezinambuzane ezizixhobo ze-biological control. Oku kubonisa ukuba iinzame zokukhulisa nokukhutshwa kwezinambuzane ezizixhobo ze-biological control eMzantsi Afrika azanelanga kwaye kufuneka zandiswe, ngakumbi kwiindawo apho kukho ukhutsho olumbalwa olwenziweyo kunye nezityalo ze-cactus ezininzi ezifumaneka khona, njengePhondo laseLimpopo. Iimpembelelo yokukhutshwa kwezinambuzane ezizixhobo ze-biological control kwizityalo ze-cactus zavavanywa ngokujonga ubunizi bezinambuzane ezizixhobo ze-biological control, ukuxinana kwezityalo ze-cactus ekujoliswe kuzo kunye nemveliso yokuzala kwezityalo ze-cactus phambi nasemva kokuba kukhutshwe izinambuzane ezizixhobo ze-biological control. Ubungakanani bezityalo ze-cactus kunye nemveliso yokuzala ziye zacutheka emva kokukhutshwa kwezinambuzane ezizixhobo ze-biological control kwinzityalo ezintathu ze-cactus ebekujoliswe uvavanyo kuzo, ngelixa ixesha lophononongo lalifutshane kakhulu ukuvavanya unciphiso kwisityalo se-cactus sesine. Izibonelelo zabasebenzisi bomhlaba zaye zavavanywa kusetyenziswa uhlobo lwemibuzo. Abasebenzisi bomhlaba balubona ukusetyenziswa kwezinambuzane ezizixhobo ze-biological control njengendlela yolawulo olusebenzayo, yi81% yabasebenzisi bomhlaba echaze ukuba izityalo ze-cactus zecuthekile emva kokukhutshwa kwezinambuzane ezizixhobo ze-biological control emhlabeni wabo. Amashumi amane anesithoba eepesenti zabasebenzisi bomhlaba bakholelwa ukuba impembelelo ezingalunganga ze-cactus zincitshisiwe kwaye baxhamle kakhulu kumhlaba wabo okoko lwaphunyenzwa. Oludliwano-ndlebe belwenziwe kubasebenzisi bomhlaba kwisithuba seminyaka emine emva kokuba kukhutshwe izinambuzane ezizixhobo ze-biological control, kulindeleke ukuba ipesenti yabasebenzisi bomhlaba abathe bafumana izibonelelo kwi-biological control lonyuke kwixesha elizayo. Amashumi alithoba anesixhenxe ekhulwini abasebenzisi bomhlaba bachaze ukuba izinambuzane ezizixhobo ze-biological control zikhuselekile kwaye khange zidle kuzo naziphi na ezinye izityalo ezingezi eze-cactus ebekujoliswe kuzo okanye zineempembelelo eyingozi. Ezi mbono ziyabonisa ukuba abasebenzi bomhlaba bayithatha i-biological control njengendlela ekhuselekileyo nesebenzayo yokulawula izityalo ze-cactus zamanye amazwe. Olu phononongo luqinisekisa ukuba ulawulo olusebenzisa izinambuzane ezizixhobo ze-biological control yindlela esebenzayo nekhuselekileyo yokulawula iCactaceae yamanye amazwe. Ikwangolokuqala ukuvavanya ezinye zezibonelelo ezizuzwe ngabasebenzisi bomhlaba ngenxa ye-biological control yezityalo ze-cactus. Nangona kunjalo kucacile ukuba ukwandisa inzame zokukhulisa nokukhupha ngobuninzi izinambuzane ezizixhobo ze-biological control kuyafuneka ukuze uMzantsi Afrika ufumane izibonelelo eziphakamileyo enokubakho ngokusetyenziswa kwe zinambuzane ezizixhobo ze-biological control zokulawula ukhula lwe-cactus olukhoyo kweli lizwe. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: Mnqeta, Zezethu
- Date: 2022-04-08
- Subjects: Cactus Biological control South Africa , Noxious weeds South Africa , Invasive plants Biological control South Africa , Insects as biological pest control agents South Africa , Cochineal insect South Africa , Mealybugs South Africa , Agricultural productivity South Africa
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/294631 , vital:57239 , DOI 10.21504/10962/294631
- Description: Invasive alien cacti are prominent weeds that threaten indigenous biodiversity and have a negative impact on agricultural productivity in South Africa. These plants are problematic because they form dense thickets that reduce the carrying capacity of rangelands; restrict the movement of livestock and wildlife thus reducing access to shade and water sources; and are directly harmful to livestock, wildlife and people due to their sharp spines. Biological control is the most effective, affordable and environmentally friendly method to control invasive alien cacti and minimize their negative impacts. Cochineal insects (Dactylopius spp.: Dactylopiidae) and the gall-forming mealybug, Hypogeococcus sp. (Pseudococcidae) are used as biological control agents for cacti. The agents are however poor dispersers, so mass-rearing and augmentative releases are required in order to establish the agents at sites where they are needed. This study aimed to evaluate the mass-rearing and release efforts of cactus biological control in South Africa, quantify the impact of the biological control agents on cactus plant populations through long-term monitoring, and assess the benefits accrued due to the biological control agents through the perceptions of land-users. An assessment of the effectiveness of the release effort for cactus biological control agents was conducted by comparing where biological control agents have been released with the known distribution of the target weeds. Only 26% of the quarter degree squares that are known to be occupied by invasive alien cacti have had biological control agents released in them. This indicated that the mass-rearing and release efforts in South Africa are inadequate and should be increased, especially in areas where few releases have been made and many cacti are present, such as the Limpopo Province. The impact of the biological control agents on cactus plant populations was assessed by monitoring agent densities, target plant densities and target plant reproductive outputs before and after releases. Plant biomass and reproductive output were reduced by biological control agents for three of the target weeds that were assessed, while the duration of the study was too short to measure reductions for the fourth target weed. Benefits to land-users were then quantified through a questionnaire survey. Land-users perceived biological control as an effective management option, with 81% of the land-users reporting that there was less invasive alien cactus after releasing biological control agents on their land. Forty-nine percent of the land-users believed that the negative impacts of the cactus had been reduced and that they benefited more from their land since control was achieved. Since land-users were only interviewed within four years of the releases being conducted, it is expected that the percentage of land-users who gained benefits from biological control will increase in future. Ninety-seven percent of the land-users stated that the agents were safe and had not fed on any other plants or had any detrimental impacts. These perceptions indicated that land-users regarded biological control as a safe and effective method of controlling invasive alien cacti. This study confirms that biological control is an effective and safe way of controlling invasive alien Cactaceae. It is also the first to assess some of the benefits that land-users have accrued due to biological control of cactus weeds. It is however evident that a greater mass-rearing and release effort is required for South Africa to get the maximum benefits possible from the use of the biological control agents for cactus weeds that are available in the country. , Izityalo ze-cactus ezisuka kwamanye amazwe zilukhula olubalaseleyo, olwenza ingxaki kwintlobo ngeentlobo zezityalo nezilwanyana kwaye ezizityalo zinefuthe neziphumo ezingalunganga kwimveliso yezolimo eMzantsi Afrika. Ezi zizityalo ziyingxaki kuba zenza amatyholo ashinyeneyo athi anciphise umthamo wokusebenzisa umhlaba: zinqanda ukuhamba nogkukhululekileyo kwemfuyo nezilwanyana zasendle ngokwenza oko zingakwazi ukufikelela emthuzini xa kutshisa nakwimithombo yamanzi yokusela; zikwayiyo nengozi kwimfuyo, izilwanyana zasendle kunye nabantu ngenxa yamave abukhali afumaneka kwezizityalo. Ukulawula nokwehliza ubunzini nezinga lemigcipheko yezizityalo, kusetyenziswa indlela ekuthiwa yi-biological control. Lendlela yeyona ndlela isebenza ngokuphucukileyo, efikelelayo, nengenabungozi kokusingqongileyo. Izinambuzane ze- cochineal (i-Dactylopius spp.: Dactylopiidae) kunye ne-mealybug, i-Hypogeococcus sp. (Pseudococcidae) zisetyenziswe njengezixhobo ze-biological control ezinceda ukulawula ezizityalo ze-cactus zingafunekiyo. Ingxaki yazo ezizinambuzane zizixhobo ze-biological control zingentla kukuba azikwazi kuzisasaza ngokwazo ukuba zifikelele nakwizityalo ezikude ngoko ke ukukhuliswa nokukhutshwa ngobuninzi bazo kuyafuneka ukukhawulelana nalengxaki kunye nokwandisa amathuba wokuba zifikelele kuzozonke izityalo ze-cactus ekufuneka zizilawule. Olu phononongo lujolise ekuvavanyeni iinzame zokukhulisa ngobuninzi nokukhupha ezezinambuzane zizixhobo ze-bioloigical control zokulawula izityalo ze-cactus eMzantsi Afrika, ukujonga ubungakanani befuthe notshintsho elenziwa zezinambuzane zizixhobo ze-bioloigical control kwizityalo ze-cactus emva kwexesha elide lokuzijonga, kunye nokuvavanya inzuzo efunyenwe ngenxa yokulawula ezizityalo ze-cactus ngokwemibono yabasebenzisi bomhlaba. Uvavanyo lweenzame zokukhutshwa kwezixhobo zezixhobo zezinambuzane ze-bioloigical control kwizityalo ze-cactus lwenziwa ngokuthelekisa iindawo apho izixhobo zezinambuzane ze-biological control zikhutshwe khona kunye neendawo apho izityalo ze-cactus kwaziwayo ukuba ziyafumaneka khona. Yi-26% kuphela yesikwere sekota eyaziwayo ukuba kukhona izityalo ze-cactus nalapho kukhutshwe khona kwezinambuzane ezizixhobo ze-biological control. Oku kubonisa ukuba iinzame zokukhulisa nokukhutshwa kwezinambuzane ezizixhobo ze-biological control eMzantsi Afrika azanelanga kwaye kufuneka zandiswe, ngakumbi kwiindawo apho kukho ukhutsho olumbalwa olwenziweyo kunye nezityalo ze-cactus ezininzi ezifumaneka khona, njengePhondo laseLimpopo. Iimpembelelo yokukhutshwa kwezinambuzane ezizixhobo ze-biological control kwizityalo ze-cactus zavavanywa ngokujonga ubunizi bezinambuzane ezizixhobo ze-biological control, ukuxinana kwezityalo ze-cactus ekujoliswe kuzo kunye nemveliso yokuzala kwezityalo ze-cactus phambi nasemva kokuba kukhutshwe izinambuzane ezizixhobo ze-biological control. Ubungakanani bezityalo ze-cactus kunye nemveliso yokuzala ziye zacutheka emva kokukhutshwa kwezinambuzane ezizixhobo ze-biological control kwinzityalo ezintathu ze-cactus ebekujoliswe uvavanyo kuzo, ngelixa ixesha lophononongo lalifutshane kakhulu ukuvavanya unciphiso kwisityalo se-cactus sesine. Izibonelelo zabasebenzisi bomhlaba zaye zavavanywa kusetyenziswa uhlobo lwemibuzo. Abasebenzisi bomhlaba balubona ukusetyenziswa kwezinambuzane ezizixhobo ze-biological control njengendlela yolawulo olusebenzayo, yi81% yabasebenzisi bomhlaba echaze ukuba izityalo ze-cactus zecuthekile emva kokukhutshwa kwezinambuzane ezizixhobo ze-biological control emhlabeni wabo. Amashumi amane anesithoba eepesenti zabasebenzisi bomhlaba bakholelwa ukuba impembelelo ezingalunganga ze-cactus zincitshisiwe kwaye baxhamle kakhulu kumhlaba wabo okoko lwaphunyenzwa. Oludliwano-ndlebe belwenziwe kubasebenzisi bomhlaba kwisithuba seminyaka emine emva kokuba kukhutshwe izinambuzane ezizixhobo ze-biological control, kulindeleke ukuba ipesenti yabasebenzisi bomhlaba abathe bafumana izibonelelo kwi-biological control lonyuke kwixesha elizayo. Amashumi alithoba anesixhenxe ekhulwini abasebenzisi bomhlaba bachaze ukuba izinambuzane ezizixhobo ze-biological control zikhuselekile kwaye khange zidle kuzo naziphi na ezinye izityalo ezingezi eze-cactus ebekujoliswe kuzo okanye zineempembelelo eyingozi. Ezi mbono ziyabonisa ukuba abasebenzi bomhlaba bayithatha i-biological control njengendlela ekhuselekileyo nesebenzayo yokulawula izityalo ze-cactus zamanye amazwe. Olu phononongo luqinisekisa ukuba ulawulo olusebenzisa izinambuzane ezizixhobo ze-biological control yindlela esebenzayo nekhuselekileyo yokulawula iCactaceae yamanye amazwe. Ikwangolokuqala ukuvavanya ezinye zezibonelelo ezizuzwe ngabasebenzisi bomhlaba ngenxa ye-biological control yezityalo ze-cactus. Nangona kunjalo kucacile ukuba ukwandisa inzame zokukhulisa nokukhupha ngobuninzi izinambuzane ezizixhobo ze-biological control kuyafuneka ukuze uMzantsi Afrika ufumane izibonelelo eziphakamileyo enokubakho ngokusetyenziswa kwe zinambuzane ezizixhobo ze-biological control zokulawula ukhula lwe-cactus olukhoyo kweli lizwe. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2022
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- Date Issued: 2022-04-08