The transformative potential of intersecting arts-based inquiry and environmental learning in urban South Africa: a focus on socio-ecological water pedagogies
- Authors: James, Anna Katharine
- Date: 2022-04-08
- Subjects: Environmental education South Africa , Water conservation Study and teaching South Africa , Art in environmental education South Africa , Social learning South Africa , Educational sociology South Africa , Water-supply Social aspects South Africa , Critical realism , Socio-ecological education
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/290660 , vital:56772 , DOI 10.21504/10962/290660
- Description: In this study I explore and explain transformative potential in arts-based environmental learning with a focus on water pedagogy. The study took place over a period of four years, where approximately 40 school pupils between the ages of 10 and 17 years-old were engaged in participatory arts-based inquiries into water located across unequal neighbourhoods in Cape Town, South Africa. Educators, school learners, citizens and decision-makers hold different historical, cultural, political and spiritual perspectives on water. These play a role in shaping what is termed in this research the ‘hydro-social cycle’. Yet, due to dominant ideas of what counts as knowing and truth, educators in educational settings struggle to account for the complexity of water, limiting educational encounters to a partial knowing leading mostly to limited unimaginative framings of problems and solutions. My focus on transformative potential in learning is derived from a concern for how environmental education encounters and the sense-making they enable, are infused by socio-economic, political, and historical elements, specifically colonialism, capitalism, and white supremacist racism. The connections between the multiple layers of capitalist crisis and the ever-urgent environmental crisis are not adequately made in mainstream forms of water education. The research explores how arts-based pedagogy could enable a productive meeting of critical environmental education with ecological literacies. Within this positioning, transformative potential considers how educational engagements position questions about water within the social life of participants/learners and inform learning that leads to fuller and more nuanced greater knowledge. Theoretically, I work with an interrogation of critical education theory, underlaboured by critical realism which enabled me to rigorously consider how claims to knowing are shaped by their accompanying assumptions of what is real. Drawing on recent debates in critical education theory, I resist the notion of critique as ideology and engage instead in the craftsmanship of contextual and responsive inquiry practice. This has enabled me to articulate processes and relationships in water education encounters with meaningful understandings of the effects of simultaneous crises rooted in racial capitalism and environmental crisis. My methodological approach is arts-based educational research with a directive to reflect upon educational encounters in an integrated way. It includes two parts informing the facilitation and analysis of open-ended learning processes. One component was arts-based inquiry practice developed for exploring complexity, drawing on the thinking of Norris (2009, 2011) and Finley (2016, 2017). The second part holds reflective space for these encounters guided by the practice of pedagogical narration inspired by the Reggio Amelia approach, demonstrated by Pacini-Ketchabaw, Nxumalo, Kocher, Elliot and Sanchez (2014). Clarifying the intellectual work of a responsive educator-researcher, pedagogical narration brings multiple theoretical lenses into conversation with emergent dimensions of educational process. In practice, in order to transgress the dominance of colonial white supremacist knowledge frames of water, I needed to be curious, to be confounded, to expect the unexpected in the educational encounters with participants and this mirroring of practice was emulated by the participants as they followed their own questions about water in Mzansi (South Africa). In our work together we came up against assumptions we had previously not questioned as individuals. Together we explored the implications of this by, for example, questioning who is responsible for saving water. These explorations required bringing together science knowledge and everyday knowledge at multiple scales: the household, catchment, government and global. It required us to be critical of how language and images are mobilized in public communication and school curriculums; for example, representations of water are infused with history and power in a way that impacts how we know and teach about water. The transformative potential of this pedagogical space is generated through acts of creative expression which are seen as acts of absenting absence, for example exhibiting through play how water use in the household interconnects with gender and age relationships. As such, creative expression through multiple mediums or more-than-text enables a deeper understanding of water as well as openings for interdisciplinary engagement with learning about water. My research found that in bringing together the contributions of critical education and environmental education in practice, two shifts are needed: environmental educators need to view ecological literacy as inseparable from the social and political. The knowledge that is shared about water in the classroom has social and political implications. On the other hand, critical educators need to better locate justice concerns in the material and ecological world at scale. Arts-based inquiry, as a kind of scaffolding for pedagogical process, has the potential to enable these shifts by opening up fixed analytical frames. Making these shifts requires a reflective practice on the part of the educator to navigate the inherited blind spots in environmental learning and critical education, such as dualities. One way to do this is for the educator to identify absences, as articulated in the Critical Realist tradition, and consider how these absences might be absented. This differs from a simplistic process of critique in the possibilities it opens up for collaboration between different schools of thought rather than further polarisation and alienation between educators and knowledge keepers on social ecologies. These insights have relevance for many sites of environmental education practice, such as natural science lecturers, school teachers or community activists. It is knowledge-learning work emergent from and responsive to complex ecological crisis, which requires everyone to rethink and open up to new ways of being, seeing and doing around these issues. The transformative potential of this work is that the thinking and transforming at all scales can be catalysed and grounded through the arts based educational encounters with the participants. , Thesis (PhD) -- Faculty of Education, Education, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: James, Anna Katharine
- Date: 2022-04-08
- Subjects: Environmental education South Africa , Water conservation Study and teaching South Africa , Art in environmental education South Africa , Social learning South Africa , Educational sociology South Africa , Water-supply Social aspects South Africa , Critical realism , Socio-ecological education
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/290660 , vital:56772 , DOI 10.21504/10962/290660
- Description: In this study I explore and explain transformative potential in arts-based environmental learning with a focus on water pedagogy. The study took place over a period of four years, where approximately 40 school pupils between the ages of 10 and 17 years-old were engaged in participatory arts-based inquiries into water located across unequal neighbourhoods in Cape Town, South Africa. Educators, school learners, citizens and decision-makers hold different historical, cultural, political and spiritual perspectives on water. These play a role in shaping what is termed in this research the ‘hydro-social cycle’. Yet, due to dominant ideas of what counts as knowing and truth, educators in educational settings struggle to account for the complexity of water, limiting educational encounters to a partial knowing leading mostly to limited unimaginative framings of problems and solutions. My focus on transformative potential in learning is derived from a concern for how environmental education encounters and the sense-making they enable, are infused by socio-economic, political, and historical elements, specifically colonialism, capitalism, and white supremacist racism. The connections between the multiple layers of capitalist crisis and the ever-urgent environmental crisis are not adequately made in mainstream forms of water education. The research explores how arts-based pedagogy could enable a productive meeting of critical environmental education with ecological literacies. Within this positioning, transformative potential considers how educational engagements position questions about water within the social life of participants/learners and inform learning that leads to fuller and more nuanced greater knowledge. Theoretically, I work with an interrogation of critical education theory, underlaboured by critical realism which enabled me to rigorously consider how claims to knowing are shaped by their accompanying assumptions of what is real. Drawing on recent debates in critical education theory, I resist the notion of critique as ideology and engage instead in the craftsmanship of contextual and responsive inquiry practice. This has enabled me to articulate processes and relationships in water education encounters with meaningful understandings of the effects of simultaneous crises rooted in racial capitalism and environmental crisis. My methodological approach is arts-based educational research with a directive to reflect upon educational encounters in an integrated way. It includes two parts informing the facilitation and analysis of open-ended learning processes. One component was arts-based inquiry practice developed for exploring complexity, drawing on the thinking of Norris (2009, 2011) and Finley (2016, 2017). The second part holds reflective space for these encounters guided by the practice of pedagogical narration inspired by the Reggio Amelia approach, demonstrated by Pacini-Ketchabaw, Nxumalo, Kocher, Elliot and Sanchez (2014). Clarifying the intellectual work of a responsive educator-researcher, pedagogical narration brings multiple theoretical lenses into conversation with emergent dimensions of educational process. In practice, in order to transgress the dominance of colonial white supremacist knowledge frames of water, I needed to be curious, to be confounded, to expect the unexpected in the educational encounters with participants and this mirroring of practice was emulated by the participants as they followed their own questions about water in Mzansi (South Africa). In our work together we came up against assumptions we had previously not questioned as individuals. Together we explored the implications of this by, for example, questioning who is responsible for saving water. These explorations required bringing together science knowledge and everyday knowledge at multiple scales: the household, catchment, government and global. It required us to be critical of how language and images are mobilized in public communication and school curriculums; for example, representations of water are infused with history and power in a way that impacts how we know and teach about water. The transformative potential of this pedagogical space is generated through acts of creative expression which are seen as acts of absenting absence, for example exhibiting through play how water use in the household interconnects with gender and age relationships. As such, creative expression through multiple mediums or more-than-text enables a deeper understanding of water as well as openings for interdisciplinary engagement with learning about water. My research found that in bringing together the contributions of critical education and environmental education in practice, two shifts are needed: environmental educators need to view ecological literacy as inseparable from the social and political. The knowledge that is shared about water in the classroom has social and political implications. On the other hand, critical educators need to better locate justice concerns in the material and ecological world at scale. Arts-based inquiry, as a kind of scaffolding for pedagogical process, has the potential to enable these shifts by opening up fixed analytical frames. Making these shifts requires a reflective practice on the part of the educator to navigate the inherited blind spots in environmental learning and critical education, such as dualities. One way to do this is for the educator to identify absences, as articulated in the Critical Realist tradition, and consider how these absences might be absented. This differs from a simplistic process of critique in the possibilities it opens up for collaboration between different schools of thought rather than further polarisation and alienation between educators and knowledge keepers on social ecologies. These insights have relevance for many sites of environmental education practice, such as natural science lecturers, school teachers or community activists. It is knowledge-learning work emergent from and responsive to complex ecological crisis, which requires everyone to rethink and open up to new ways of being, seeing and doing around these issues. The transformative potential of this work is that the thinking and transforming at all scales can be catalysed and grounded through the arts based educational encounters with the participants. , Thesis (PhD) -- Faculty of Education, Education, 2022
- Full Text:
- Date Issued: 2022-04-08
Socio-historical analysis of organisational change: a case study of Zimbabwe posts (Zimpost), 2010–2020
- Kambarami-Zengeni, Faith Chipo
- Authors: Kambarami-Zengeni, Faith Chipo
- Date: 2022-10-14
- Subjects: Organizational change Zimbabwe , Fordism , Industrial management , Taylor, Frederick Winslow, 1856-1915 , Industrial relations , Postal service Management
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/327920 , vital:61170 , DOI 10.21504/10962/327920
- Description: Postal organisations play an important role in the provision of basic communication services. In Zimbabwe, post offices have a large physical distribution network of over 240 post offices country-wide to make communication services accessible to the populace. However, e-substitution has threatened mail business significantly. Postal operators globally are experiencing declining mail volumes in the face of advanced information and communication technologies. The overall goal of this thesis was to undertake a socio-historical analysis of organisational change at ZimPost using Taylorism, Fordism and post-Fordism as broad ideal types to explain how industry evolves in different phases of capitalism. National politics and economics play an integral role in how Taylorism, Fordism and post-Fordism assumed at ZimPost. Studies on these broad organising types have mainly focused on private sector organisations. However, this thesis argues that these analytical paradigms are also valid in public sector organisations, but they will unfold differently given the context in which change is experienced. Using a qualitative approach, the study established that the 1980s and 1990s can best be described as the ‘golden years’ of postal services in Zimbabwe, characterised by mass production and mass consumption of postal products and services. At that time the Posts and Telecommunications Corporation enjoyed a monopoly of postal services in the country. The stable market share, competitive salaries for postal workers, increased unionisation and a fairly stable economy enabled a Fordist regime of accumulation to develop. The cycle broke down when the mode of regulation was weakened by national economic and political changes towards the late 1990s. PTC started to experience a decline in the consumption of postal products. The decline was also attributed to increased competition from smaller private courier operators that could provide specialised services to a market with changing needs. With increased competition, the advancement of information, and communication technologies, mail volumes dwindled. This period can best be described as the crisis of Fordism at ZimPost. In the year 2000, the government unbundled the posts and telecommunications corporation to create four companies including Zimbabwe Posts. This was perceived as one of the most radical organisational changes in the history of postal services in Zimbabwe. More organisational changes took place at ZimPost that can best be described as characteristics of post-Fordism. These changes were attempts by ZimPost to remain relevant in light of the economic, political and technological changes taking place in the country. The postal operator introduced customised products in the form of agency services, supported by increased use of information and communication technologies in the post office. Organisational changes at ZimPost were shaped mainly by the economic and political environment in which they took place. Organisational change is complex, changes do not follow a linear pattern, they are processual. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Kambarami-Zengeni, Faith Chipo
- Date: 2022-10-14
- Subjects: Organizational change Zimbabwe , Fordism , Industrial management , Taylor, Frederick Winslow, 1856-1915 , Industrial relations , Postal service Management
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/327920 , vital:61170 , DOI 10.21504/10962/327920
- Description: Postal organisations play an important role in the provision of basic communication services. In Zimbabwe, post offices have a large physical distribution network of over 240 post offices country-wide to make communication services accessible to the populace. However, e-substitution has threatened mail business significantly. Postal operators globally are experiencing declining mail volumes in the face of advanced information and communication technologies. The overall goal of this thesis was to undertake a socio-historical analysis of organisational change at ZimPost using Taylorism, Fordism and post-Fordism as broad ideal types to explain how industry evolves in different phases of capitalism. National politics and economics play an integral role in how Taylorism, Fordism and post-Fordism assumed at ZimPost. Studies on these broad organising types have mainly focused on private sector organisations. However, this thesis argues that these analytical paradigms are also valid in public sector organisations, but they will unfold differently given the context in which change is experienced. Using a qualitative approach, the study established that the 1980s and 1990s can best be described as the ‘golden years’ of postal services in Zimbabwe, characterised by mass production and mass consumption of postal products and services. At that time the Posts and Telecommunications Corporation enjoyed a monopoly of postal services in the country. The stable market share, competitive salaries for postal workers, increased unionisation and a fairly stable economy enabled a Fordist regime of accumulation to develop. The cycle broke down when the mode of regulation was weakened by national economic and political changes towards the late 1990s. PTC started to experience a decline in the consumption of postal products. The decline was also attributed to increased competition from smaller private courier operators that could provide specialised services to a market with changing needs. With increased competition, the advancement of information, and communication technologies, mail volumes dwindled. This period can best be described as the crisis of Fordism at ZimPost. In the year 2000, the government unbundled the posts and telecommunications corporation to create four companies including Zimbabwe Posts. This was perceived as one of the most radical organisational changes in the history of postal services in Zimbabwe. More organisational changes took place at ZimPost that can best be described as characteristics of post-Fordism. These changes were attempts by ZimPost to remain relevant in light of the economic, political and technological changes taking place in the country. The postal operator introduced customised products in the form of agency services, supported by increased use of information and communication technologies in the post office. Organisational changes at ZimPost were shaped mainly by the economic and political environment in which they took place. Organisational change is complex, changes do not follow a linear pattern, they are processual. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2022
- Full Text:
- Date Issued: 2022-10-14
Socio-historical analysis of organisational change: a case study of Zimbabwe Posts (Zimpost), 2010–2020
- Kambarami-Zengeni, Faith Chipo
- Authors: Kambarami-Zengeni, Faith Chipo
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/422518 , vital:71954 , DOI 10.21504/10962/422518
- Description: Postal organisations play an important role in the provision of basic communication services. In Zimbabwe, post offices have a large physical distribution network of over 240 post offices country-wide to make communication services accessible to the populace. However, e-substitution has threatened mail business significantly. Postal operators globally are experiencing declining mail volumes in the face of advanced information and communication technologies. The overall goal of this thesis was to undertake a socio-historical analysis of organisational change at ZimPost using Taylorism, Fordism and post-Fordism as broad ideal types to explain how industry evolves in different phases of capitalism. National politics and economics play an integral role in how Taylorism, Fordism and post-Fordism assumed at ZimPost. Studies on these broad organising types have mainly focused on private sector organisations. However, this thesis argues that these analytical paradigms are also valid in public sector organisations, but they will unfold differently given the context in which change is experienced. Using a qualitative approach, the study established that the 1980s and 1990s can best be described as the ‘golden years’ of postal services in Zimbabwe, characterised by mass production and mass consumption of postal products and services. At that time the Posts and Telecommunications Corporation enjoyed a monopoly of postal services in the country. The stable market share, competitive salaries for postal workers, increased unionisation and a fairly stable economy enabled a Fordist regime of accumulation to develop. The cycle broke down when the mode of regulation was weakened by national economic and political changes towards the late 1990s. PTC started to experience a decline in the consumption of postal products. The decline was also attributed to increased competition from smaller private courier operators that could provide specialised services to a market with changing needs. With increased competition, the advancement of information, and communication technologies, mail volumes dwindled. This period can best be described as the crisis of Fordism at ZimPost. In the year 2000, the government unbundled the posts and telecommunications corporation to create four companies including Zimbabwe Posts. This was perceived as one of the most radical organisational changes in the history of postal services in Zimbabwe. More organisational changes took place at ZimPost that can best be described as characteristics of post-Fordism. These changes were attempts by ZimPost to remain relevant in light of the economic, political and technological changes taking place in the country. The postal operator introduced customised products in the form of agency services, supported by increased use of information and communication technologies in the post office. Organisational changes at ZimPost were shaped mainly by the economic and political environment in which they took place. Organisational change is complex, changes do not follow a linear pattern, they are processual. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2023
- Full Text:
- Date Issued: 2022-10-14
- Authors: Kambarami-Zengeni, Faith Chipo
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/422518 , vital:71954 , DOI 10.21504/10962/422518
- Description: Postal organisations play an important role in the provision of basic communication services. In Zimbabwe, post offices have a large physical distribution network of over 240 post offices country-wide to make communication services accessible to the populace. However, e-substitution has threatened mail business significantly. Postal operators globally are experiencing declining mail volumes in the face of advanced information and communication technologies. The overall goal of this thesis was to undertake a socio-historical analysis of organisational change at ZimPost using Taylorism, Fordism and post-Fordism as broad ideal types to explain how industry evolves in different phases of capitalism. National politics and economics play an integral role in how Taylorism, Fordism and post-Fordism assumed at ZimPost. Studies on these broad organising types have mainly focused on private sector organisations. However, this thesis argues that these analytical paradigms are also valid in public sector organisations, but they will unfold differently given the context in which change is experienced. Using a qualitative approach, the study established that the 1980s and 1990s can best be described as the ‘golden years’ of postal services in Zimbabwe, characterised by mass production and mass consumption of postal products and services. At that time the Posts and Telecommunications Corporation enjoyed a monopoly of postal services in the country. The stable market share, competitive salaries for postal workers, increased unionisation and a fairly stable economy enabled a Fordist regime of accumulation to develop. The cycle broke down when the mode of regulation was weakened by national economic and political changes towards the late 1990s. PTC started to experience a decline in the consumption of postal products. The decline was also attributed to increased competition from smaller private courier operators that could provide specialised services to a market with changing needs. With increased competition, the advancement of information, and communication technologies, mail volumes dwindled. This period can best be described as the crisis of Fordism at ZimPost. In the year 2000, the government unbundled the posts and telecommunications corporation to create four companies including Zimbabwe Posts. This was perceived as one of the most radical organisational changes in the history of postal services in Zimbabwe. More organisational changes took place at ZimPost that can best be described as characteristics of post-Fordism. These changes were attempts by ZimPost to remain relevant in light of the economic, political and technological changes taking place in the country. The postal operator introduced customised products in the form of agency services, supported by increased use of information and communication technologies in the post office. Organisational changes at ZimPost were shaped mainly by the economic and political environment in which they took place. Organisational change is complex, changes do not follow a linear pattern, they are processual. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2023
- Full Text:
- Date Issued: 2022-10-14
The incorporation of GeoGebra as a visualisation tool to teach calculus in teacher education institutions: the Zambian case
- Authors: Kangwa, Lemmy
- Date: 2022-10-14
- Subjects: GeoGebra , Calculus Study and teaching (Secondary) Zambia , Visual learning
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/405470 , vital:70174 , DOI
- Description: This qualitative case study investigated teacher educators’ (lecturers) use of the dynamic mathematics software, GeoGebra, to teach calculus in three teacher education institutions (TEIs) in Zambia. Visualisation, a key characteristic of GeoGebra, is increasingly gaining recognition of playing a critical role in mathematics teaching and learning, especially in problem solving tasks. It is considered a powerful didactical tool for students to construct mental and physical representations that can enhance conceptual understanding of mathematics. GeoGebra is a visualisation tool that can be used for problem-oriented teaching and foster mathematical experiments and discoveries. GeoGebra’s inherent visualisation characteristics align well with the teaching of calculus, the mathematical domain of this study. The study (whose research methodology was underpinned by the interpretive paradigm) was undertaken with a broader goal of designing and implementing GeoGebra applets and instructional materials on various calculus topics. The study is located within the “Teaching and Learning Mathematics with GeoGebra (TLMG) project” – a project that involves mathematics teachers and lecturers in Zambia. The case in this study is the six mathematics lecturers who co-designed and used GeoGebra applets to teach derivatives and integrals to pre-service mathematics teachers in TEIs. The unit of analysis therefore is the six lecturers’ use of GeoGebra as a visualisation tool to teach calculus to enhance conceptual understanding, their perceptions and experiences of using GeoGebra and the enabling and constraining factors of using GeoGebra to teach and learn mathematics. The data for the study were video recordings of observations and interviews of lecturers. The data was analysed thematically and was guided and informed by an analytical framework adopted from the theory of constructivism – the umbrella theoretical framework of this study – and the models of Technological Pedagogical Content Knowledge (TPACK), and the Technology Acceptance Model (TAM). A detailed analysis of the lecturers’ interactions with the applets enabled me to gain insights into the participants’ experiences and perceptions of GeoGebra applets in the teaching and learning process. The findings of the study revealed that the visualisation characteristics of GeoGebra generally enhanced the conceptual understanding of calculus. It also revealed that adequate training, coupled with sufficient knowledge of the subject matter in calculus, were necessary for lecturers to use GeoGebra effectively, and that the lack of resources and expertise were major hindrances in the use of GeoGebra to teach mathematics in TEIs. It also revealed that there is a need to equip GeoGebra with other features that would make it more versatile, and suggested a teaching approach that would complement the use of conventional methods and GeoGebra to provide a link between abstract and concrete concepts of calculus. , Thesis (PhD) -- Faculty of Education, Education, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Kangwa, Lemmy
- Date: 2022-10-14
- Subjects: GeoGebra , Calculus Study and teaching (Secondary) Zambia , Visual learning
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/405470 , vital:70174 , DOI
- Description: This qualitative case study investigated teacher educators’ (lecturers) use of the dynamic mathematics software, GeoGebra, to teach calculus in three teacher education institutions (TEIs) in Zambia. Visualisation, a key characteristic of GeoGebra, is increasingly gaining recognition of playing a critical role in mathematics teaching and learning, especially in problem solving tasks. It is considered a powerful didactical tool for students to construct mental and physical representations that can enhance conceptual understanding of mathematics. GeoGebra is a visualisation tool that can be used for problem-oriented teaching and foster mathematical experiments and discoveries. GeoGebra’s inherent visualisation characteristics align well with the teaching of calculus, the mathematical domain of this study. The study (whose research methodology was underpinned by the interpretive paradigm) was undertaken with a broader goal of designing and implementing GeoGebra applets and instructional materials on various calculus topics. The study is located within the “Teaching and Learning Mathematics with GeoGebra (TLMG) project” – a project that involves mathematics teachers and lecturers in Zambia. The case in this study is the six mathematics lecturers who co-designed and used GeoGebra applets to teach derivatives and integrals to pre-service mathematics teachers in TEIs. The unit of analysis therefore is the six lecturers’ use of GeoGebra as a visualisation tool to teach calculus to enhance conceptual understanding, their perceptions and experiences of using GeoGebra and the enabling and constraining factors of using GeoGebra to teach and learn mathematics. The data for the study were video recordings of observations and interviews of lecturers. The data was analysed thematically and was guided and informed by an analytical framework adopted from the theory of constructivism – the umbrella theoretical framework of this study – and the models of Technological Pedagogical Content Knowledge (TPACK), and the Technology Acceptance Model (TAM). A detailed analysis of the lecturers’ interactions with the applets enabled me to gain insights into the participants’ experiences and perceptions of GeoGebra applets in the teaching and learning process. The findings of the study revealed that the visualisation characteristics of GeoGebra generally enhanced the conceptual understanding of calculus. It also revealed that adequate training, coupled with sufficient knowledge of the subject matter in calculus, were necessary for lecturers to use GeoGebra effectively, and that the lack of resources and expertise were major hindrances in the use of GeoGebra to teach mathematics in TEIs. It also revealed that there is a need to equip GeoGebra with other features that would make it more versatile, and suggested a teaching approach that would complement the use of conventional methods and GeoGebra to provide a link between abstract and concrete concepts of calculus. , Thesis (PhD) -- Faculty of Education, Education, 2022
- Full Text:
- Date Issued: 2022-10-14
Integrative systematic structuring of the widespread psammophiid snakes (Psammophiidae): a multi-evidence species delineation approach
- Authors: Keates, Chad
- Date: 2021-10-29
- Subjects: Psammophis South Africa , Herpetology , Herpetology Africa , Molecular biology , Psammophis Classification , Psammophis Genetics , Psammophis Morphology , Psammophis Phylogeny , Morphology Mathematics , Psammophylax
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/295077 , vital:57288 , DOI 10.21504/10962/295079
- Description: Species form the foundations upon which we build our understanding of the natural world. Although a focus of much scientific attention, our understanding of species is stunted by the intrinsic ‘fuzziness’ of boundaries within nature. Due to the complexity of the evolutionary process, coupled with an ever-changing abiotic landscape, species are hard to delineate, even at the best of times. Whilst various species concepts and sophisticated delimitation methods have helped scientists tease apart species, many species complexes persist. This is because taxonomy is a discrete ordering system imposed upon the continuous and intercalated structure of life. To improve our understanding of a wide-ranging family of snakes, I investigated the taxonomy and evolutionary structuring within Psammophiidae using both molecular and morphological approaches, employing phylogenetic, phylogeographic, and morphometric analyses on the group. The systematic complexity of the family (as evidenced by past research) coupled with the group’s widespread distribution and ecological importance, made the taxon an ideal candidate for a broad-sweeping multi-level systematic analysis using multiple species delimitation methods. Additionally, in this thesis I attempted to build on the ground-breaking work of Christopher Kelly by addressing several knowledge gaps identified within the family, and in so doing, produce the most thorough evolutionary and taxonomic study of Psammophiidae possible. Given the taxonomic uncertainty associated with the family, Chapter Two used a representative sampling from every available species (near complete taxon sampling approach) in the family. The chapter used both standard and time-calibrated phylogenetic modelling and distance/threshold-based species delimitation, to elucidate the finer-level structuring within the family. Geometric morphometrics was used to determine whether there were diagnosable differences in head structure between the different genera. The final phylogenetic tree incorporated 320 samples, representing the most comprehensive phylogenetic reconstruction of the family to date. By using a near-complete taxon sampling approach, I was able to resolve previously unsupported relationships within the family whilst also identifying several novel instances of an under- and over-appreciation of species diversity within the family. Geometric morphometrics also identified clear distinctions between genera based on head shape (head width and ‘beakedness’). This chapter showcased the importance of complete taxon sampling and robust methodology for species delimitation and the deleterious effect of species concepts when implemented in isolation. In Chapter Three, I narrowed the scope of the study to focus on the genus level. Psammophylax (Fitzinger 1843) is an abundant, yet poorly studied genus of grass snakes, endemic to Africa. The generalist nature of the genus and wide-spanning distributions of the constituent species has given rise to several subspecies and a poor understanding of the taxonomic structuring within the genus. The overlapping distributions (sympatry) of many of Psammophylax species, coupled with the potential for cryptic speciation via mechanisms such as convergent evolution, made the group the ideal candidate for a broad-sweeping systematic study (as evidenced in Chapter Two). By applying the suite of analyses used in Chapter Two to the generic level, we aimed to determine the effectiveness of a multi-evidence species delineation approach when tackling systematic problems at lower taxonomic levels. A genetic phylogeny of six of the seven species was estimated using multiple phylogenetic and distance/ threshold-based species delimitation methods. To support the molecular analyses, we conducted morphological analyses on the body (traditional morphology) and head (geometric morphometrics) separately. Phylogenetic analyses recovered a similar topology to past studies, but with better resolution and node support. I found substantial genetic structuring within the genus, supported by significantly different head shapes between Ps. a. acutus and other Psammophylax species. Psammophylax a. acutus was recovered as sister to its congeners, and sequence divergence values and morphometrics supported its recognition as a new genus. Increased sampling in East Africa (Tanzania, Kenya, and Ethiopia) revealed that Psammophylax multisquamis is polyphyletic, necessitating the description of a new, morphologically cryptic, species from northern Tanzania. The distribution of Ps. multisquamis sensu stricto is likely restricted to Kenya and Ethiopia. Within this chapter, taxon-specific phylogenetic analyses yielded stronger intrageneric support as compared to Chapter Two, allowing for more defensible conclusions about taxonomical amendments. Geometric morphometrics proved similarly useful (as compared to Chapter Two) in teasing apart genera within the family but lacked the robustness to delineate species within Psammophylax with confidence, highlighting the apparent convergence of form within the genus. In Chapter Four, I investigated the evolutionary structuring within the Southern African endemic Psammophylax rhombeatus. The structural and environmental heterogeneity within the region has given rise to many morphological forms distributed throughout the country, with previous studies neglecting the associated molecular significance of these forms. Irrespective of their small sample sizes, both Chapter Two and Three identified substantial phylogenetic structuring within the species, making Ps. rhombeatus the ideal candidate for a multi-faceted systematic review, using a combination of phylogenetics, geometric morphometrics and, for the first time in this species, phylogeographic analyses. By investigating a single species, in detail, I was able to assess the effectiveness of the methodologies implemented in previous chapters on systematic sorting using the multi-evidence species delineation approach. Phylogenetic and haplotype analysis retrieved four well-supported clades: southeast South Africa (SESA), southwest South Africa (SWSA), north-eastern South Africa (NESA) and western South Africa (WSA). Although not variable enough to warrant taxonomic re-evaluation, the clades represented important genetic hotspots, with relatively high intraspecific genetic divergence values separating them, irrespective of the small geographic distances separating populations. This is likely a product of the taxon’s habitat-generalist lifestyle, enabling them to bypass vicariant barriers that might otherwise cause speciation in less versatile species. The clades are also geographically distinct, with little overlap, indicating previous vicariance, a finding that is supported by the split of Ps. rhombeatus from Ps. ocellatus in the mid-Pliocene, followed by the diversification of Ps. rhombeatus into four clades throughout the Pleistocene. The genetic structuring observed in Ps. rhombeatus may be a product of population expansion following ancient refugial isolation (potentially Last Glacial Maximum [LGM]). The molecular distinctiveness of the clades was not replicated in the morphological component of this chapter, with neither dorsal nor lateral geometric morphometric analyses of head shape showing any discernible distinctiveness based on geography. Whilst head shape has not been shown to be an effective delineator of evolutionary units at the species level (within this taxon), body colour, scalation, and snout-vent length has been linked to morphotypes within the species based on the work of Broadley (1966). These morphological groupings are loosely attributable to the molecular clades identified in the phylogenetic analyses, highlighting the complex interplay of genetic and morphological characteristics in the process of speciation, and their representation in systematic accounts. This thesis represents the most thorough evolutionary and systematic study of the family currently possible. In addition to identifying and describing both a new genus and species, this thesis also highlighted several instances of an over- and under-appreciation of species diversity within Psammophiidae. By applying a multi-evidence species delineation approach to this thesis, I show the intricacy of the evolutionary process (at various taxonomic levels) and showcase the ease to which species boundaries can be confounded when species concepts are implemented in isolation. These findings also highlighted the importance of sample size, sample range, species delimitation method on the outcome of taxonomic analyses, and their interpretation. Lastly, this thesis addressed the knowledge gaps left by Christopher Kelly’s PhD work and investigated the findings of recent papers that attempted to do the same. Whilst this study answers the questions of old, the taxon-intensive focus revealed several new knowledge gaps within the family, highlighting how much we know about snake systematics, and furthermore, how much we still need to learn about evolutionary structuring. , Thesis (PhD) -- Faculty of Science, Environmental Science, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Keates, Chad
- Date: 2021-10-29
- Subjects: Psammophis South Africa , Herpetology , Herpetology Africa , Molecular biology , Psammophis Classification , Psammophis Genetics , Psammophis Morphology , Psammophis Phylogeny , Morphology Mathematics , Psammophylax
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/295077 , vital:57288 , DOI 10.21504/10962/295079
- Description: Species form the foundations upon which we build our understanding of the natural world. Although a focus of much scientific attention, our understanding of species is stunted by the intrinsic ‘fuzziness’ of boundaries within nature. Due to the complexity of the evolutionary process, coupled with an ever-changing abiotic landscape, species are hard to delineate, even at the best of times. Whilst various species concepts and sophisticated delimitation methods have helped scientists tease apart species, many species complexes persist. This is because taxonomy is a discrete ordering system imposed upon the continuous and intercalated structure of life. To improve our understanding of a wide-ranging family of snakes, I investigated the taxonomy and evolutionary structuring within Psammophiidae using both molecular and morphological approaches, employing phylogenetic, phylogeographic, and morphometric analyses on the group. The systematic complexity of the family (as evidenced by past research) coupled with the group’s widespread distribution and ecological importance, made the taxon an ideal candidate for a broad-sweeping multi-level systematic analysis using multiple species delimitation methods. Additionally, in this thesis I attempted to build on the ground-breaking work of Christopher Kelly by addressing several knowledge gaps identified within the family, and in so doing, produce the most thorough evolutionary and taxonomic study of Psammophiidae possible. Given the taxonomic uncertainty associated with the family, Chapter Two used a representative sampling from every available species (near complete taxon sampling approach) in the family. The chapter used both standard and time-calibrated phylogenetic modelling and distance/threshold-based species delimitation, to elucidate the finer-level structuring within the family. Geometric morphometrics was used to determine whether there were diagnosable differences in head structure between the different genera. The final phylogenetic tree incorporated 320 samples, representing the most comprehensive phylogenetic reconstruction of the family to date. By using a near-complete taxon sampling approach, I was able to resolve previously unsupported relationships within the family whilst also identifying several novel instances of an under- and over-appreciation of species diversity within the family. Geometric morphometrics also identified clear distinctions between genera based on head shape (head width and ‘beakedness’). This chapter showcased the importance of complete taxon sampling and robust methodology for species delimitation and the deleterious effect of species concepts when implemented in isolation. In Chapter Three, I narrowed the scope of the study to focus on the genus level. Psammophylax (Fitzinger 1843) is an abundant, yet poorly studied genus of grass snakes, endemic to Africa. The generalist nature of the genus and wide-spanning distributions of the constituent species has given rise to several subspecies and a poor understanding of the taxonomic structuring within the genus. The overlapping distributions (sympatry) of many of Psammophylax species, coupled with the potential for cryptic speciation via mechanisms such as convergent evolution, made the group the ideal candidate for a broad-sweeping systematic study (as evidenced in Chapter Two). By applying the suite of analyses used in Chapter Two to the generic level, we aimed to determine the effectiveness of a multi-evidence species delineation approach when tackling systematic problems at lower taxonomic levels. A genetic phylogeny of six of the seven species was estimated using multiple phylogenetic and distance/ threshold-based species delimitation methods. To support the molecular analyses, we conducted morphological analyses on the body (traditional morphology) and head (geometric morphometrics) separately. Phylogenetic analyses recovered a similar topology to past studies, but with better resolution and node support. I found substantial genetic structuring within the genus, supported by significantly different head shapes between Ps. a. acutus and other Psammophylax species. Psammophylax a. acutus was recovered as sister to its congeners, and sequence divergence values and morphometrics supported its recognition as a new genus. Increased sampling in East Africa (Tanzania, Kenya, and Ethiopia) revealed that Psammophylax multisquamis is polyphyletic, necessitating the description of a new, morphologically cryptic, species from northern Tanzania. The distribution of Ps. multisquamis sensu stricto is likely restricted to Kenya and Ethiopia. Within this chapter, taxon-specific phylogenetic analyses yielded stronger intrageneric support as compared to Chapter Two, allowing for more defensible conclusions about taxonomical amendments. Geometric morphometrics proved similarly useful (as compared to Chapter Two) in teasing apart genera within the family but lacked the robustness to delineate species within Psammophylax with confidence, highlighting the apparent convergence of form within the genus. In Chapter Four, I investigated the evolutionary structuring within the Southern African endemic Psammophylax rhombeatus. The structural and environmental heterogeneity within the region has given rise to many morphological forms distributed throughout the country, with previous studies neglecting the associated molecular significance of these forms. Irrespective of their small sample sizes, both Chapter Two and Three identified substantial phylogenetic structuring within the species, making Ps. rhombeatus the ideal candidate for a multi-faceted systematic review, using a combination of phylogenetics, geometric morphometrics and, for the first time in this species, phylogeographic analyses. By investigating a single species, in detail, I was able to assess the effectiveness of the methodologies implemented in previous chapters on systematic sorting using the multi-evidence species delineation approach. Phylogenetic and haplotype analysis retrieved four well-supported clades: southeast South Africa (SESA), southwest South Africa (SWSA), north-eastern South Africa (NESA) and western South Africa (WSA). Although not variable enough to warrant taxonomic re-evaluation, the clades represented important genetic hotspots, with relatively high intraspecific genetic divergence values separating them, irrespective of the small geographic distances separating populations. This is likely a product of the taxon’s habitat-generalist lifestyle, enabling them to bypass vicariant barriers that might otherwise cause speciation in less versatile species. The clades are also geographically distinct, with little overlap, indicating previous vicariance, a finding that is supported by the split of Ps. rhombeatus from Ps. ocellatus in the mid-Pliocene, followed by the diversification of Ps. rhombeatus into four clades throughout the Pleistocene. The genetic structuring observed in Ps. rhombeatus may be a product of population expansion following ancient refugial isolation (potentially Last Glacial Maximum [LGM]). The molecular distinctiveness of the clades was not replicated in the morphological component of this chapter, with neither dorsal nor lateral geometric morphometric analyses of head shape showing any discernible distinctiveness based on geography. Whilst head shape has not been shown to be an effective delineator of evolutionary units at the species level (within this taxon), body colour, scalation, and snout-vent length has been linked to morphotypes within the species based on the work of Broadley (1966). These morphological groupings are loosely attributable to the molecular clades identified in the phylogenetic analyses, highlighting the complex interplay of genetic and morphological characteristics in the process of speciation, and their representation in systematic accounts. This thesis represents the most thorough evolutionary and systematic study of the family currently possible. In addition to identifying and describing both a new genus and species, this thesis also highlighted several instances of an over- and under-appreciation of species diversity within Psammophiidae. By applying a multi-evidence species delineation approach to this thesis, I show the intricacy of the evolutionary process (at various taxonomic levels) and showcase the ease to which species boundaries can be confounded when species concepts are implemented in isolation. These findings also highlighted the importance of sample size, sample range, species delimitation method on the outcome of taxonomic analyses, and their interpretation. Lastly, this thesis addressed the knowledge gaps left by Christopher Kelly’s PhD work and investigated the findings of recent papers that attempted to do the same. Whilst this study answers the questions of old, the taxon-intensive focus revealed several new knowledge gaps within the family, highlighting how much we know about snake systematics, and furthermore, how much we still need to learn about evolutionary structuring. , Thesis (PhD) -- Faculty of Science, Environmental Science, 2021
- Full Text:
- Date Issued: 2021-10-29
Synthesis, In-Silico molecular modelling and biological studies of 1,4-Dihydroxyanthraquinone and its derivatives
- Authors: Kisula, Lydia Mboje
- Date: 2022-10-14
- Subjects: Computer simulation , Molecules Models , Dihydroxyanthraquinone , Trypanosomiasis , Leishmaniasis , Docking
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365828 , vital:65793 , DOI https://doi.org/10.21504/10962/365828
- Description: This current study of investigation reports on the synthesis of 1,4-dihydroxyanthraquinone and its derivatives on explorations of their medicinal potential. The study initially aimed to synthesize an analogue of a natural anthraquinone, 1,3,6-trihydroxy-7-((S)-1- hydroxyethyl)anthracene-9,10-dione 5 using Friedel-Crafts acylation of phthalic anhydride and a benzene derivative. Synthetic transformation of anacardic acid 63, obtained as a by- product of the cashew industry successfully afforded 4-ethoxyisobenzofuran-1,3-dione 89. However, when attempted to couple 4-ethoxyisobenzofuran-1,3-dione 89 with 2- hydroxyacetophenone 91 in a Friedel-Crafts acylation manner to form 2-acetyl-1,8- dihydroxyanthracene-9,10-dione 87 the reaction did not work efficiently. A simple derivative of benzene which is; benzene-1,4-diol 102 was reacted instead with 3-ethoxyphthalic acid 71 and isobenzofuran-1,3-dione 96 to form 1,4,5-trihydroxy anthraquinone 72 and 1,4- dihydroxyanthraquinone 42, respectively. A modified Marschalk reaction was then used to introduce the hydroxyl alkyl group to 1,4-dihydroxy anthraquinone 42, which allowed further elaboration of the hydroxyl-substituent in moderate to good yields (22-80%). A molecular docking study was performed using Schrödinger software to predict the binding affinity of the test compounds to the target protein trypanothione reductase (PDB ID: 6BU7). An in-vitro screening of 1,4-dihydroxyanthraquinone derivatives and some selected precursors for antitrypanosomal, antiplasmodial, antibacterial, and cytotoxicity activities produced encouraging results. Derivatives of anacardic acid and cardanol from CNSL were found to have moderate activity against trypanosomes with no activity against Plasmodium falciparum. Almost 63% of synthesized 1,4-dihydroxyanthraquinone derivatives displayed activity against trypanosomes. The in-vitro evaluation and the in silico molecular docking studies revealed that 1,4-dihydroxyanthraquinone derivatives can be potential drug-like candidates active against T.brucei parasites (IC50 = 0.70-1.20 μM). Only four 1,4- iv dihydroxyanthraquinone derivatives with thiosemicarbazone, chloride, pyrrole, and diethanolamine functionality displayed activity against Plasmodium falciparum (IC50 = 3.17- 14.36 μM). In-vitro evaluated of test compounds against antibacterial screen and cytotoxicity effects significantly showed that 2-hydroxy-6-pentadecylbenzoic acid 63a and 2-((2- chlorophenyl)(piperazin-1-yl) methyl)-1,4-dihydroxyanthracene-9,10-dione 78 have potency against Staphylococcus aureus and reduced the viability of the cells below 20% at an initial concentration of 50 μg/mL. Only 1,4-dihydroxyanthraquinone derivatives with thiosemicarbazone 76, piperazine 78, and diethanolamine 80 motifs were active against HeLa cells and reduced the viability of cells below 20% at a concentration of 50 μg/mL. In conclusion, this current reported study has generated useful knowlege on the applicability of the agro-waste CNSL as an agent active against trypanosomiasis but also as a low-cost starting material to synthesize hydroxy anthraquinones. The study has further given an overview to the understanding of the medicinal value 1,4-dihydroxyanthraquinone derivatives as promising candidates towards developing drugs suitable for treating neglected tropical diseases particularly trypanosomiasis. , Thesis (PhD) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Kisula, Lydia Mboje
- Date: 2022-10-14
- Subjects: Computer simulation , Molecules Models , Dihydroxyanthraquinone , Trypanosomiasis , Leishmaniasis , Docking
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365828 , vital:65793 , DOI https://doi.org/10.21504/10962/365828
- Description: This current study of investigation reports on the synthesis of 1,4-dihydroxyanthraquinone and its derivatives on explorations of their medicinal potential. The study initially aimed to synthesize an analogue of a natural anthraquinone, 1,3,6-trihydroxy-7-((S)-1- hydroxyethyl)anthracene-9,10-dione 5 using Friedel-Crafts acylation of phthalic anhydride and a benzene derivative. Synthetic transformation of anacardic acid 63, obtained as a by- product of the cashew industry successfully afforded 4-ethoxyisobenzofuran-1,3-dione 89. However, when attempted to couple 4-ethoxyisobenzofuran-1,3-dione 89 with 2- hydroxyacetophenone 91 in a Friedel-Crafts acylation manner to form 2-acetyl-1,8- dihydroxyanthracene-9,10-dione 87 the reaction did not work efficiently. A simple derivative of benzene which is; benzene-1,4-diol 102 was reacted instead with 3-ethoxyphthalic acid 71 and isobenzofuran-1,3-dione 96 to form 1,4,5-trihydroxy anthraquinone 72 and 1,4- dihydroxyanthraquinone 42, respectively. A modified Marschalk reaction was then used to introduce the hydroxyl alkyl group to 1,4-dihydroxy anthraquinone 42, which allowed further elaboration of the hydroxyl-substituent in moderate to good yields (22-80%). A molecular docking study was performed using Schrödinger software to predict the binding affinity of the test compounds to the target protein trypanothione reductase (PDB ID: 6BU7). An in-vitro screening of 1,4-dihydroxyanthraquinone derivatives and some selected precursors for antitrypanosomal, antiplasmodial, antibacterial, and cytotoxicity activities produced encouraging results. Derivatives of anacardic acid and cardanol from CNSL were found to have moderate activity against trypanosomes with no activity against Plasmodium falciparum. Almost 63% of synthesized 1,4-dihydroxyanthraquinone derivatives displayed activity against trypanosomes. The in-vitro evaluation and the in silico molecular docking studies revealed that 1,4-dihydroxyanthraquinone derivatives can be potential drug-like candidates active against T.brucei parasites (IC50 = 0.70-1.20 μM). Only four 1,4- iv dihydroxyanthraquinone derivatives with thiosemicarbazone, chloride, pyrrole, and diethanolamine functionality displayed activity against Plasmodium falciparum (IC50 = 3.17- 14.36 μM). In-vitro evaluated of test compounds against antibacterial screen and cytotoxicity effects significantly showed that 2-hydroxy-6-pentadecylbenzoic acid 63a and 2-((2- chlorophenyl)(piperazin-1-yl) methyl)-1,4-dihydroxyanthracene-9,10-dione 78 have potency against Staphylococcus aureus and reduced the viability of the cells below 20% at an initial concentration of 50 μg/mL. Only 1,4-dihydroxyanthraquinone derivatives with thiosemicarbazone 76, piperazine 78, and diethanolamine 80 motifs were active against HeLa cells and reduced the viability of cells below 20% at a concentration of 50 μg/mL. In conclusion, this current reported study has generated useful knowlege on the applicability of the agro-waste CNSL as an agent active against trypanosomiasis but also as a low-cost starting material to synthesize hydroxy anthraquinones. The study has further given an overview to the understanding of the medicinal value 1,4-dihydroxyanthraquinone derivatives as promising candidates towards developing drugs suitable for treating neglected tropical diseases particularly trypanosomiasis. , Thesis (PhD) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-10-14
With dreams in our hands: Towards transgressive knowledge-making cultures
- Authors: Knowles, Corinne Ruth
- Date: 2023-10-13
- Subjects: African feminism , Pedagogy , Political sociology , Knowledge, Theory of Political aspects , Transformative learning
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/402955 , vital:69909 , DOI 10.21504/10962/402955
- Description: Knowledge-making in universities is not neutral and takes different forms. This thesis critically examines the politics of knowledge to propose and present a transgressive schema for knowledge-making that is co-created with students. It emerges from teaching and learning encounters in the Humanities Extended Studies (ES) Programme at Rhodes University, where for the past decade we have experimented with different ways of knowledge-making that run counter to conventional pedagogic practices. We set up a project for the thesis that allowed us to work with knowledge in ways that are Afrocentric, and that hold and nurture our dreams. The theory and methodology of the project are explained in the first academic paper for this PhD by publication. The project and its derivatives use an African Feminist framing, and centre the ontoepistemologies of African young people who find themselves alienated and marginalised by a western bias in university curricula. Former ES student volunteers came up with topics, responded to them, reviewed each other’s work, and co-wrote two academic papers that demonstrate a praxis of African Feminist research and pedagogic principles. Two further projects practise the principles that emerge from the primary project, and together they have tested knowledge-making cultures that inspire critical thinking and creative humanity. These are explained in two further academic papers. One is co-written with the copresenter of an online inter-continental short course for PhD students on African Feminist Research Methodology. The other is single authored, and introduces the third project, a Political and International Studies third-year course on African Feminist theory. The schema for knowledge-making uses the hand, which holds our dream, as a descriptive metaphor. Each of the five fingers of the hand represents an aspect of how we have collaborated on the projects and in lecture rooms, and what this has taught us about how to nurture and inspire the dreams of young African people through transgressive knowledgemaking cultures. The five aspects – framing, activating, seeing, creating, imagining – are mutually constitutive elements of knowledge-making that are introduced throughout the thesis, and explained in careful detail in the conclusion as a synthesis of the collaborations. , Siphethe amaphupha ezandleni zethu: ukwenza iinckubeko zolwazi ezigxile ekuphazamiseni isiqhelo Isishwankathelo Ukwenziwa kolwazi kwiiunivesithi asiyonto engathathi cala kwaye yenzeka ngeendlelangeendlela. Le thisisi iphonononga ipolitiki yolwazi ngenjongo yokucebisa nokuvelisa iindlela zokwenziwa kolwazi ezigxile ekuphazamiseni kwesiqhelo, ndlela leyo eyenziwa ngentsebenziswano nabafundi. Le Ndlela yokuphazamisa isiqhelo ivela kwindlela zokufunda nokufundisa kwinkqubo yeExtended Studies kwiUnivesithi iRhodes, apho kwiminyaka elishumi edlulileyo besisebenzisa amalinge ohlukileyo okwenza ulwazi ohlukileyo kwindlela zokufunda eziqhelekileyo. Siqulunqe inkqubo yale thisisi evumele ukuba sisebenze nolwazi ngendlela ekhokhelelisa ubuAfrika phambile, nkqubo leyo eyondla nebamba amaphupha ethu. Inkcazo-bungcali neendlela zokwenza uphando lwalo msebenzi zicacisiwe kwiphepha lokuqala lethisisi yePhD ezakupapashwa. Lo msebenzi neminye imisebenzi efana nawo isebenzisa iAfrikan Feminism ngenjongo yokubeka ngokusesikweni ndlela le ingxile kwindlela yokufundisa neengcambu zayo ezizinze eAfrika, kwaye ikhokhelisa imfundo yabantu abatsha abazifumana besenziwe amakheswa nabahlelelekileyo kunyenjwa kwasentshona kwizifundo zaseunivesithi. Abafundi ababefunda kwiES baze nezihloko, yangabo abaziphendulayo, bahlola imisebenzi yoogxa babo, kwaye bancedisa ekubhaleni amaphepha amabini abonakalisa indlela yokuphanda kusetyenziswa iziseko zokufunda zeAfrikan Feminism. Eminye imisebenzi isebenzise iziseko eziphuma kulo msebenzi wokuqala, kwaye yomibini le misebenzi iphonononga iinkcubeko zokwenza ulwazi ezikhuthaza ukuzikisa ukucinga nobuntu obunobuchule. Oku kucaciswa nzulu kumaphepha amabini. Omnye ubhalwe nomfundi kunye nombhali obefundisa kwikhosi emfutshane ebikwi-intanethi ephakathi kwamazwekazi eyenzelwe abafundi be- PhD kwiAfrican Feminist Research Methodology. Omnye umsebenzi ubhalwe ngumntu omnye, nothi wazise umsebenzi wesithathu, ikhosi yonyaka wesithathu yePolitical and International Studies yenkcazo-bungcali iAfrican Feminism. Icebo lokwenza ulwazi lisebenzisa isandla esibambe amaphupha ethu, njengesafobe esinika inkcazelo. Umnwe ngamnye umele indlela esisebenzisene ngayo kule misebenzi nakumagumbi okufundela, kunye nesikufundileyo ngokukhulisa nokukhuthaza amaphupha wabantu abasebatsha baseAfrika ngokusebenzisa imisebenzi egxile kwiinkcubeko zolwazi eziphazamisa ukwenziwa kolwazi ngendlela eqhelekileyo. Imiba emihlanu- ukwenza isakhelo, ukuqalisa, ukubona, ukudala, ukusebenzisa imifanekiso ntelekelelo- iyingqokelela yenxalenye yokwenza ulwazi ngendlela enentsebenziswano kwaye ezi ziseko zaziswa banzi kwithisisi, kwaye zicaciswe gabalala kwisishwankathelo njengengqokelela yentsebenziswano kulo msebenzi. , Thesis (PhD) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-10-13
- Authors: Knowles, Corinne Ruth
- Date: 2023-10-13
- Subjects: African feminism , Pedagogy , Political sociology , Knowledge, Theory of Political aspects , Transformative learning
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/402955 , vital:69909 , DOI 10.21504/10962/402955
- Description: Knowledge-making in universities is not neutral and takes different forms. This thesis critically examines the politics of knowledge to propose and present a transgressive schema for knowledge-making that is co-created with students. It emerges from teaching and learning encounters in the Humanities Extended Studies (ES) Programme at Rhodes University, where for the past decade we have experimented with different ways of knowledge-making that run counter to conventional pedagogic practices. We set up a project for the thesis that allowed us to work with knowledge in ways that are Afrocentric, and that hold and nurture our dreams. The theory and methodology of the project are explained in the first academic paper for this PhD by publication. The project and its derivatives use an African Feminist framing, and centre the ontoepistemologies of African young people who find themselves alienated and marginalised by a western bias in university curricula. Former ES student volunteers came up with topics, responded to them, reviewed each other’s work, and co-wrote two academic papers that demonstrate a praxis of African Feminist research and pedagogic principles. Two further projects practise the principles that emerge from the primary project, and together they have tested knowledge-making cultures that inspire critical thinking and creative humanity. These are explained in two further academic papers. One is co-written with the copresenter of an online inter-continental short course for PhD students on African Feminist Research Methodology. The other is single authored, and introduces the third project, a Political and International Studies third-year course on African Feminist theory. The schema for knowledge-making uses the hand, which holds our dream, as a descriptive metaphor. Each of the five fingers of the hand represents an aspect of how we have collaborated on the projects and in lecture rooms, and what this has taught us about how to nurture and inspire the dreams of young African people through transgressive knowledgemaking cultures. The five aspects – framing, activating, seeing, creating, imagining – are mutually constitutive elements of knowledge-making that are introduced throughout the thesis, and explained in careful detail in the conclusion as a synthesis of the collaborations. , Siphethe amaphupha ezandleni zethu: ukwenza iinckubeko zolwazi ezigxile ekuphazamiseni isiqhelo Isishwankathelo Ukwenziwa kolwazi kwiiunivesithi asiyonto engathathi cala kwaye yenzeka ngeendlelangeendlela. Le thisisi iphonononga ipolitiki yolwazi ngenjongo yokucebisa nokuvelisa iindlela zokwenziwa kolwazi ezigxile ekuphazamiseni kwesiqhelo, ndlela leyo eyenziwa ngentsebenziswano nabafundi. Le Ndlela yokuphazamisa isiqhelo ivela kwindlela zokufunda nokufundisa kwinkqubo yeExtended Studies kwiUnivesithi iRhodes, apho kwiminyaka elishumi edlulileyo besisebenzisa amalinge ohlukileyo okwenza ulwazi ohlukileyo kwindlela zokufunda eziqhelekileyo. Siqulunqe inkqubo yale thisisi evumele ukuba sisebenze nolwazi ngendlela ekhokhelelisa ubuAfrika phambile, nkqubo leyo eyondla nebamba amaphupha ethu. Inkcazo-bungcali neendlela zokwenza uphando lwalo msebenzi zicacisiwe kwiphepha lokuqala lethisisi yePhD ezakupapashwa. Lo msebenzi neminye imisebenzi efana nawo isebenzisa iAfrikan Feminism ngenjongo yokubeka ngokusesikweni ndlela le ingxile kwindlela yokufundisa neengcambu zayo ezizinze eAfrika, kwaye ikhokhelisa imfundo yabantu abatsha abazifumana besenziwe amakheswa nabahlelelekileyo kunyenjwa kwasentshona kwizifundo zaseunivesithi. Abafundi ababefunda kwiES baze nezihloko, yangabo abaziphendulayo, bahlola imisebenzi yoogxa babo, kwaye bancedisa ekubhaleni amaphepha amabini abonakalisa indlela yokuphanda kusetyenziswa iziseko zokufunda zeAfrikan Feminism. Eminye imisebenzi isebenzise iziseko eziphuma kulo msebenzi wokuqala, kwaye yomibini le misebenzi iphonononga iinkcubeko zokwenza ulwazi ezikhuthaza ukuzikisa ukucinga nobuntu obunobuchule. Oku kucaciswa nzulu kumaphepha amabini. Omnye ubhalwe nomfundi kunye nombhali obefundisa kwikhosi emfutshane ebikwi-intanethi ephakathi kwamazwekazi eyenzelwe abafundi be- PhD kwiAfrican Feminist Research Methodology. Omnye umsebenzi ubhalwe ngumntu omnye, nothi wazise umsebenzi wesithathu, ikhosi yonyaka wesithathu yePolitical and International Studies yenkcazo-bungcali iAfrican Feminism. Icebo lokwenza ulwazi lisebenzisa isandla esibambe amaphupha ethu, njengesafobe esinika inkcazelo. Umnwe ngamnye umele indlela esisebenzisene ngayo kule misebenzi nakumagumbi okufundela, kunye nesikufundileyo ngokukhulisa nokukhuthaza amaphupha wabantu abasebatsha baseAfrika ngokusebenzisa imisebenzi egxile kwiinkcubeko zolwazi eziphazamisa ukwenziwa kolwazi ngendlela eqhelekileyo. Imiba emihlanu- ukwenza isakhelo, ukuqalisa, ukubona, ukudala, ukusebenzisa imifanekiso ntelekelelo- iyingqokelela yenxalenye yokwenza ulwazi ngendlela enentsebenziswano kwaye ezi ziseko zaziswa banzi kwithisisi, kwaye zicaciswe gabalala kwisishwankathelo njengengqokelela yentsebenziswano kulo msebenzi. , Thesis (PhD) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-10-13
Stock structure of Patagonian toothfish Dissostichus eleginoides (Smitt 1898, family Nototheniidae) in the Southwest Atlantic
- Authors: Lee, Brendon
- Date: 2022-10-14
- Subjects: Otoliths , Patagonian toothfish Geographical distribution , Fish tagging , Biogeography , Microstructure , Microchemistry
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365599 , vital:65763 , DOI https://doi.org/10.21504/10962/365599
- Description: The identification of discrete self-sustaining productive units in marine populations is essential for achieving sustainable fisheries objectives. Marine fish populations frequently exhibit dynamic characteristics across their life-histories, displaying variability in spatial structure and mixing patterns, both within and among populations. The incoherent application of management boundaries on biological populations can bias stock assessment results and have important implications on sustainable fisheries management. Patagonian toothfish (Dissostichus eleginoides) is a long-lived, slow-growing, late-maturing, deep-sea, benthopelagic species. It forms the basis of important and highly lucrative industrial and artisanal fisheries across its distribution. Patagonian toothfish have complex life-histories characterised by high dispersal potential during the egg and larval phase, a wide depth range because of their ontogenetic migratory behaviour, and large adult size that is capable of undertaking long-distance active movements (>200 km). These characteristics provide opportunities for high levels of connectivity, and as such, the stock structure is not well understood. We applied an integrated, multidisciplinary approach to provide an improved understanding of the complex stock structure dynamics for Patagonian toothfish on the Patagonian Shelf, specifically in relation to the shelf, slope, and deep-sea plains around the Falkland Islands. Research results were focused on aspects pertaining to (1) geographic variation in phenotypic characters (otolith shape); (2) a description of the spatial-temporal distribution patterns; (3) the active movements of deep-sea adults (tag-recapture study); and (4) the identification of early life-history dispersal through otolith microstructure and microchemical chronologies. Results from the study indicate high regional connectivity during the early life-history stages derived from at least two spawning contingents into spatially discrete nursery areas (cohort groups) on the Falklands Shelf. Fish followed distinct ontogenetic pathways into deeper waters adjacent to the areas wherein juvenile settlement into a demersal habitat occurred. There is little to no evidence of mixing among cohort groups during their ontogenetic migration into deep-sea adult habitats, reflecting a mixed population based on oceanographically defined egg and larval dispersal. The majority of the adult component of the population continue to display high site fidelity. However, between 9 and 25% of the population, consisting predominantly of larger reproductively capable adults undertake long-distance dispersal behaviour, identified as home-range relocations from the adult deep-sea habitats towards three of the known southern spawning grounds in the region. Results are suggestive of a requirement for improved collaborative efforts for regionally-based management approaches with careful consideration of local stock contingents. Future monitoring and research priorities should focus on the identification of reproductive potential, dispersal pathways and settlement patterns of stock contingents to inform the dynamics of mixed stock origins across the Patagonian region. While many aspects regarding the stock structure remain unresolved, results derived from the current studies can be used to inform the development of management measures to ensure the continued recovery and sustainable management of Patagonian toothfish within the region. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Lee, Brendon
- Date: 2022-10-14
- Subjects: Otoliths , Patagonian toothfish Geographical distribution , Fish tagging , Biogeography , Microstructure , Microchemistry
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365599 , vital:65763 , DOI https://doi.org/10.21504/10962/365599
- Description: The identification of discrete self-sustaining productive units in marine populations is essential for achieving sustainable fisheries objectives. Marine fish populations frequently exhibit dynamic characteristics across their life-histories, displaying variability in spatial structure and mixing patterns, both within and among populations. The incoherent application of management boundaries on biological populations can bias stock assessment results and have important implications on sustainable fisheries management. Patagonian toothfish (Dissostichus eleginoides) is a long-lived, slow-growing, late-maturing, deep-sea, benthopelagic species. It forms the basis of important and highly lucrative industrial and artisanal fisheries across its distribution. Patagonian toothfish have complex life-histories characterised by high dispersal potential during the egg and larval phase, a wide depth range because of their ontogenetic migratory behaviour, and large adult size that is capable of undertaking long-distance active movements (>200 km). These characteristics provide opportunities for high levels of connectivity, and as such, the stock structure is not well understood. We applied an integrated, multidisciplinary approach to provide an improved understanding of the complex stock structure dynamics for Patagonian toothfish on the Patagonian Shelf, specifically in relation to the shelf, slope, and deep-sea plains around the Falkland Islands. Research results were focused on aspects pertaining to (1) geographic variation in phenotypic characters (otolith shape); (2) a description of the spatial-temporal distribution patterns; (3) the active movements of deep-sea adults (tag-recapture study); and (4) the identification of early life-history dispersal through otolith microstructure and microchemical chronologies. Results from the study indicate high regional connectivity during the early life-history stages derived from at least two spawning contingents into spatially discrete nursery areas (cohort groups) on the Falklands Shelf. Fish followed distinct ontogenetic pathways into deeper waters adjacent to the areas wherein juvenile settlement into a demersal habitat occurred. There is little to no evidence of mixing among cohort groups during their ontogenetic migration into deep-sea adult habitats, reflecting a mixed population based on oceanographically defined egg and larval dispersal. The majority of the adult component of the population continue to display high site fidelity. However, between 9 and 25% of the population, consisting predominantly of larger reproductively capable adults undertake long-distance dispersal behaviour, identified as home-range relocations from the adult deep-sea habitats towards three of the known southern spawning grounds in the region. Results are suggestive of a requirement for improved collaborative efforts for regionally-based management approaches with careful consideration of local stock contingents. Future monitoring and research priorities should focus on the identification of reproductive potential, dispersal pathways and settlement patterns of stock contingents to inform the dynamics of mixed stock origins across the Patagonian region. While many aspects regarding the stock structure remain unresolved, results derived from the current studies can be used to inform the development of management measures to ensure the continued recovery and sustainable management of Patagonian toothfish within the region. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
- Full Text:
- Date Issued: 2022-10-14
Revitalisation and indigenisation of the Science curriculum through drum making, drumming, music and dance
- Authors: Liveve, Angelius Kanyanga
- Date: 2022-10-14
- Subjects: Curriculum change Namibia , Science Study and teaching (Secondary) Namibia , Traditional ecological knowledge Namibia , Drum Performance , Drum making , Pedagogical content knowledge , Social learning
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/405482 , vital:70175 , DOI 10.21504/10962/405482
- Description: The integration of IK is a common phenomenon in many postcolonial states, where it is viewed as a means to redress the injustices of the colonial era. It is believed that the recognition of IK in education represents an acknowledgement of diversity and other ways of knowing. In Namibia, for instance, the National Curriculum for Basic Education encourages the integration of IK in Science teaching. However, this goal is still far from being achieved because the curriculum seems to be silent on how teachers should integrate IK into their teaching. As a result, research shows that many Science teachers in Namibia seem to find it difficult to integrate IK into their science teaching because they were not properly trained to do so during both their pre-service and in-service training. This suggests that there is a dire need to empower science teachers who are implementers of the curriculum on appropriate pedagogical content knowledge on how to integrate IK into their science teaching in particular. It is against this backdrop that this interventionist study sought to explore how to mobilise the indigenous technology of drum making, drumming, music and dance for cultural revitalisation and indigenisation of the science curriculum. The study is underpinned by an interpretivist paradigm and augmented with an indigenous research paradigm. The interpretivist paradigm enabled me to understand the teachers’ perspectives in their contexts. On the other hand, within the indigenous research paradigm, I used the Ubuntu perspective which afforded each of us an opportunity to understand each other’s ways of knowing, doing and being. Within these two complementary paradigms, a qualitative case study approach was employed. The case study was in the form of intervention with six Grade 10 Physics teachers from three senior secondary schools in the Kavango West Region in Namibia. Moreover, a critical friend who was a lecturer at the university and expert community members of the Unongo Cultural Youth Group who are the custodians of the cultural heritage. Data were generated using semi-structured interviews, workshop discussions (audio-recorded), observations (participatory and lesson observations), stimulated recall interviews as well as journal reflections. Vygotsky’s Socio-cultural Theory, Ogunniyi’s Contiguity Argumentation Theory and Mavhunga and Rollnick’s Topic-specific Pedagogical Content Knowledge were used as the theoretical lenses in this study. The data gathered were analysed thematically and then categorised into sub-themes and themes. The findings of the study revealed that tapping into the cultural heritage of community members through giving them a voice has great potential to revitalise and indigenise the science curriculum. It also emerged in this study that storytelling is a potential instructional strategy to make science accessible and relevant to learners. The use of the indigenous technology of drum making, drumming, music and dance contributed to the Physics teachers’ agency and empowered them to co-develop their learning and teaching support materials in the form of exemplar lesson plans that integrated IK. Moreover, their pedagogical content knowledge was enhanced through enacting such exemplar lessons and thereafter reflecting on them. The study thus recommends that those in academia should promote the use of indigenous technologies as hubs for mediating the learning of science concepts. It also recommends that learners should be taken out of their science classrooms into the community to learn IK and wisdom from expert community members, something which could assist them in understanding the science taught at school. This might also benefit teachers in effectively implementing the integration of IK in schools and thereby use learners’ cultural heritage as a starting point to enrich meaningful and authentic learning. , Thesis (PhD) -- Faculty of Education, Education, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Liveve, Angelius Kanyanga
- Date: 2022-10-14
- Subjects: Curriculum change Namibia , Science Study and teaching (Secondary) Namibia , Traditional ecological knowledge Namibia , Drum Performance , Drum making , Pedagogical content knowledge , Social learning
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/405482 , vital:70175 , DOI 10.21504/10962/405482
- Description: The integration of IK is a common phenomenon in many postcolonial states, where it is viewed as a means to redress the injustices of the colonial era. It is believed that the recognition of IK in education represents an acknowledgement of diversity and other ways of knowing. In Namibia, for instance, the National Curriculum for Basic Education encourages the integration of IK in Science teaching. However, this goal is still far from being achieved because the curriculum seems to be silent on how teachers should integrate IK into their teaching. As a result, research shows that many Science teachers in Namibia seem to find it difficult to integrate IK into their science teaching because they were not properly trained to do so during both their pre-service and in-service training. This suggests that there is a dire need to empower science teachers who are implementers of the curriculum on appropriate pedagogical content knowledge on how to integrate IK into their science teaching in particular. It is against this backdrop that this interventionist study sought to explore how to mobilise the indigenous technology of drum making, drumming, music and dance for cultural revitalisation and indigenisation of the science curriculum. The study is underpinned by an interpretivist paradigm and augmented with an indigenous research paradigm. The interpretivist paradigm enabled me to understand the teachers’ perspectives in their contexts. On the other hand, within the indigenous research paradigm, I used the Ubuntu perspective which afforded each of us an opportunity to understand each other’s ways of knowing, doing and being. Within these two complementary paradigms, a qualitative case study approach was employed. The case study was in the form of intervention with six Grade 10 Physics teachers from three senior secondary schools in the Kavango West Region in Namibia. Moreover, a critical friend who was a lecturer at the university and expert community members of the Unongo Cultural Youth Group who are the custodians of the cultural heritage. Data were generated using semi-structured interviews, workshop discussions (audio-recorded), observations (participatory and lesson observations), stimulated recall interviews as well as journal reflections. Vygotsky’s Socio-cultural Theory, Ogunniyi’s Contiguity Argumentation Theory and Mavhunga and Rollnick’s Topic-specific Pedagogical Content Knowledge were used as the theoretical lenses in this study. The data gathered were analysed thematically and then categorised into sub-themes and themes. The findings of the study revealed that tapping into the cultural heritage of community members through giving them a voice has great potential to revitalise and indigenise the science curriculum. It also emerged in this study that storytelling is a potential instructional strategy to make science accessible and relevant to learners. The use of the indigenous technology of drum making, drumming, music and dance contributed to the Physics teachers’ agency and empowered them to co-develop their learning and teaching support materials in the form of exemplar lesson plans that integrated IK. Moreover, their pedagogical content knowledge was enhanced through enacting such exemplar lessons and thereafter reflecting on them. The study thus recommends that those in academia should promote the use of indigenous technologies as hubs for mediating the learning of science concepts. It also recommends that learners should be taken out of their science classrooms into the community to learn IK and wisdom from expert community members, something which could assist them in understanding the science taught at school. This might also benefit teachers in effectively implementing the integration of IK in schools and thereby use learners’ cultural heritage as a starting point to enrich meaningful and authentic learning. , Thesis (PhD) -- Faculty of Education, Education, 2022
- Full Text:
- Date Issued: 2022-10-14
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
Integrating music and mathematics for connecting across multiple constructs of fractional understanding: an RME task design journey
- Authors: Lovemore, Tarryn Shirley
- Date: 2023-03-29
- Subjects: Communities of practice , Interdisciplinary approach in education , Fractions , Mathematics Study and teaching , Music in mathematics education , Number line
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/366200 , vital:65842 , DOI https://doi.org/10.21504/10962/366200
- Description: Two South African curricular aims: appreciating creativity in mathematics and developing conceptual understanding, motivated this study. Negative views towards mathematics and challenges in teaching and learning fractions at primary school level are reported in literature, with the part-whole construct of fractions often the sole teaching focus. Despite challenges in curriculum integration (high demands on teachers and diluting disciplines), benefits, such as motivation and creative thinking, are noted. I recognised music-mathematics integration as an opportune context for designing tasks to support learners in moving flexibly between the fraction as ratio, fraction as measure and part-whole constructs. Guided by Realistic Mathematics Education principles, I embarked on a participatory dual-design experiment in task design, grappling within three micro-Communities of Practice (micro-CoPs) and across two planes: the Design-Theorising Plane and the Grounded-Practice Plane. In the Design-Theorising Plane, I worked with my two doctoral supervisors, grappling with design obstacles and finding resolutions. COVID-19 restrictions shifted our meetings to online platforms, allowing documentation and analysis of the task design process through recording functions. In the Grounded-Practice Plane, I worked within two separate micro-CoPs, both at independent schools (eight and two participating teachers respectively). Data on the teachers’ interrogation and implementation of the designed tasks were obtained via formal and informal interviews. Their reflections informed ongoing adaptations to the task design. Data were analysed in a matrix I designed and via NVivo coding. Findings include both the product of the task design journey (eight music-mathematics lessons, resources, and representations) and the process (ten groupings of Obstacle-Resolution Cycles). Three key questions (relating to music-mathematics fidelity; to task simplification for implementation; and to appropriate music-mathematics representation) were used in addressing each Obstacle-Resolution Cycle. Designing tasks to teach the part-whole construct of fractions was relatively straightforward, but designing tasks to teach the fraction as ratio and fraction as measure constructs was more challenging. These constructs could not be conflated by superimposing the music and mathematical linear representations. Aligning them, however, allowed for moving flexibly between the constructs. The teachers reported that the integrated music-mathematics tasks and supporting resources enhanced their learners’ fractional problem-solving abilities, simultaneously promoting more positive learner dispositions towards mathematics. , Thesis (PhD) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-03-29
- Authors: Lovemore, Tarryn Shirley
- Date: 2023-03-29
- Subjects: Communities of practice , Interdisciplinary approach in education , Fractions , Mathematics Study and teaching , Music in mathematics education , Number line
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/366200 , vital:65842 , DOI https://doi.org/10.21504/10962/366200
- Description: Two South African curricular aims: appreciating creativity in mathematics and developing conceptual understanding, motivated this study. Negative views towards mathematics and challenges in teaching and learning fractions at primary school level are reported in literature, with the part-whole construct of fractions often the sole teaching focus. Despite challenges in curriculum integration (high demands on teachers and diluting disciplines), benefits, such as motivation and creative thinking, are noted. I recognised music-mathematics integration as an opportune context for designing tasks to support learners in moving flexibly between the fraction as ratio, fraction as measure and part-whole constructs. Guided by Realistic Mathematics Education principles, I embarked on a participatory dual-design experiment in task design, grappling within three micro-Communities of Practice (micro-CoPs) and across two planes: the Design-Theorising Plane and the Grounded-Practice Plane. In the Design-Theorising Plane, I worked with my two doctoral supervisors, grappling with design obstacles and finding resolutions. COVID-19 restrictions shifted our meetings to online platforms, allowing documentation and analysis of the task design process through recording functions. In the Grounded-Practice Plane, I worked within two separate micro-CoPs, both at independent schools (eight and two participating teachers respectively). Data on the teachers’ interrogation and implementation of the designed tasks were obtained via formal and informal interviews. Their reflections informed ongoing adaptations to the task design. Data were analysed in a matrix I designed and via NVivo coding. Findings include both the product of the task design journey (eight music-mathematics lessons, resources, and representations) and the process (ten groupings of Obstacle-Resolution Cycles). Three key questions (relating to music-mathematics fidelity; to task simplification for implementation; and to appropriate music-mathematics representation) were used in addressing each Obstacle-Resolution Cycle. Designing tasks to teach the part-whole construct of fractions was relatively straightforward, but designing tasks to teach the fraction as ratio and fraction as measure constructs was more challenging. These constructs could not be conflated by superimposing the music and mathematical linear representations. Aligning them, however, allowed for moving flexibly between the constructs. The teachers reported that the integrated music-mathematics tasks and supporting resources enhanced their learners’ fractional problem-solving abilities, simultaneously promoting more positive learner dispositions towards mathematics. , Thesis (PhD) -- Faculty of Education, Education, 2023
- Full Text:
- Date Issued: 2023-03-29
Fucoidans from South African brown seaweeds: establishing the link between their structure and biological properties (anti-diabetic and anti-cancer activities)
- Authors: Mabate, Blessing
- Date: 2022-10-14
- Subjects: Fucoidan , Diabetes Treatment , Cancer Treatment , Brown algae
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365677 , vital:65775 , DOI https://doi.org/10.21504/10962/365677
- Description: Type 2 diabetes mellitus (T2DM) and cancer are major non-communicable diseases causing a heavy morbidity-mortality and economic burden globally. The therapeutic efforts in managing these diseases are primarily chemotherapeutic and are associated with demerits, including side effects and toxicity, limiting the prescribed amounts. These dosage limits may cause drug resistance, another major challenge in maintaining quality global health. The pursuit of novel natural bioproducts is a reasonable strategy to add to the arsenal against T2DM and cancer. Fucoidans, sulphated fucose polysaccharides abundant in brown seaweeds, have recently become popular for their biological activities, including anti-diabetic and anti-cancer properties. However, endemic South African brown seaweeds have not been adequately explored. Therefore, this study sought to characterise fucoidans extracted from South African brown seaweeds and elucidate their structure to their biological activities. Also, this study highlighted carbohydrate and glucose metabolism as major target processes in the control efforts of T2DM and cancer using fucoidans. Harvested brown seaweeds were identified as Ecklonia radiata and Sargassum elegans. E. maxima was kindly donated by KelpX. The fucoidans were then extracted using hot water, EDTA assisted, and acid extraction protocols. The integrity of the extracted fucoidan was confirmed through structural analysis using FTIR, NMR and TGA. The fucoidan extracts were then chemically characterised to determine their carbohydrate and monosaccharide composition and sulphate content. The characterised fucoidans were profiled for inhibiting the major amylolytic enzymes, namely α-amylase and α-glucosidase. The mode of inhibition by fucoidans and synergy experiments with the commercial anti-diabetic drug acarbose were also investigated. Furthermore, the fucoidans were screened for potential anti-cancer activities on the human colorectal HCT116 cancer cell line. The cytotoxicity of fucoidans was quantified using the resazurin assay. The effect of fucoidan on HCT116 cell adhesion on the tissue culture plastic was also investigated using the crystal violet-based cell adhesion assay. In addition, cancer antimigration properties of fucoidans were also investigated using 2D wound healing and 3D spheroid-based assays. Furthermore, the long-term survival of HCT116 cells was investigated through the clonogenic assay after treatment with fucoidans. Lastly, glucose uptake and lactate export assays revealed the influence of fucoidan on glucose uptake and the glycolytic flux of HCT116 cells. Fucoidans were successfully extracted with a yield between 2.2% and 14.2% on a dry weight basis. EDTA extracts produced the highest yields than the water and the acid extracts. Ecklonia spp. fucoidans displayed the highest total carbohydrate content, with glucose and galactose being the major monosaccharides. S. elegans and commercial Fucus vesiculosus had lower carbohydrate contents but contained more sulphates than the Ecklonia spp. fucoidans. Furthermore, the extracted fucoidan contained little to no contaminants, including proteins, phenolics and uronic acids. In addition, the extracted fucoidans were determined to be >100 kDa through ultracentrifugation. Mass spectrometry also detected the most abundant peak for all fucoidans to be around 700 Da (m/z). Extracted fucoidans inhibited the activity of α-glucosidase more strongly than the commercial anti-diabetic agent acarbose but were inactive on α-amylase. Fucoidans were also shown to be mixed inhibitors of α-glucosidase. Compellingly, fucoidans synergistically inhibited α-glucosidase in combination with the anti-diabetic agent acarbose, highlighting prospects for combination therapy. Finally, fucoidans demonstrated some anti-proliferative characteristics on HCT116 cancer cells by inhibiting their ability to adhere to the tissue culture plate matrix. Furthermore, some fucoidan extracts inhibited the migration of HCT116 cancer cells from 3D spheroids. Some of our fucoidan extracts also inhibited HCT116 colony formation, demonstrating inhibition of long-term cell survival. The E. maxima water extract also inhibited glucose uptake by HCT116 cells, thereby influencing the glycolytic flux. In conclusion, biologically active fucoidans were successfully extracted from South African brown seaweeds. These fucoidans demonstrated anti-diabetic and anti-cancer properties, revealing their relevance as potential drugs for these diseases. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Mabate, Blessing
- Date: 2022-10-14
- Subjects: Fucoidan , Diabetes Treatment , Cancer Treatment , Brown algae
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365677 , vital:65775 , DOI https://doi.org/10.21504/10962/365677
- Description: Type 2 diabetes mellitus (T2DM) and cancer are major non-communicable diseases causing a heavy morbidity-mortality and economic burden globally. The therapeutic efforts in managing these diseases are primarily chemotherapeutic and are associated with demerits, including side effects and toxicity, limiting the prescribed amounts. These dosage limits may cause drug resistance, another major challenge in maintaining quality global health. The pursuit of novel natural bioproducts is a reasonable strategy to add to the arsenal against T2DM and cancer. Fucoidans, sulphated fucose polysaccharides abundant in brown seaweeds, have recently become popular for their biological activities, including anti-diabetic and anti-cancer properties. However, endemic South African brown seaweeds have not been adequately explored. Therefore, this study sought to characterise fucoidans extracted from South African brown seaweeds and elucidate their structure to their biological activities. Also, this study highlighted carbohydrate and glucose metabolism as major target processes in the control efforts of T2DM and cancer using fucoidans. Harvested brown seaweeds were identified as Ecklonia radiata and Sargassum elegans. E. maxima was kindly donated by KelpX. The fucoidans were then extracted using hot water, EDTA assisted, and acid extraction protocols. The integrity of the extracted fucoidan was confirmed through structural analysis using FTIR, NMR and TGA. The fucoidan extracts were then chemically characterised to determine their carbohydrate and monosaccharide composition and sulphate content. The characterised fucoidans were profiled for inhibiting the major amylolytic enzymes, namely α-amylase and α-glucosidase. The mode of inhibition by fucoidans and synergy experiments with the commercial anti-diabetic drug acarbose were also investigated. Furthermore, the fucoidans were screened for potential anti-cancer activities on the human colorectal HCT116 cancer cell line. The cytotoxicity of fucoidans was quantified using the resazurin assay. The effect of fucoidan on HCT116 cell adhesion on the tissue culture plastic was also investigated using the crystal violet-based cell adhesion assay. In addition, cancer antimigration properties of fucoidans were also investigated using 2D wound healing and 3D spheroid-based assays. Furthermore, the long-term survival of HCT116 cells was investigated through the clonogenic assay after treatment with fucoidans. Lastly, glucose uptake and lactate export assays revealed the influence of fucoidan on glucose uptake and the glycolytic flux of HCT116 cells. Fucoidans were successfully extracted with a yield between 2.2% and 14.2% on a dry weight basis. EDTA extracts produced the highest yields than the water and the acid extracts. Ecklonia spp. fucoidans displayed the highest total carbohydrate content, with glucose and galactose being the major monosaccharides. S. elegans and commercial Fucus vesiculosus had lower carbohydrate contents but contained more sulphates than the Ecklonia spp. fucoidans. Furthermore, the extracted fucoidan contained little to no contaminants, including proteins, phenolics and uronic acids. In addition, the extracted fucoidans were determined to be >100 kDa through ultracentrifugation. Mass spectrometry also detected the most abundant peak for all fucoidans to be around 700 Da (m/z). Extracted fucoidans inhibited the activity of α-glucosidase more strongly than the commercial anti-diabetic agent acarbose but were inactive on α-amylase. Fucoidans were also shown to be mixed inhibitors of α-glucosidase. Compellingly, fucoidans synergistically inhibited α-glucosidase in combination with the anti-diabetic agent acarbose, highlighting prospects for combination therapy. Finally, fucoidans demonstrated some anti-proliferative characteristics on HCT116 cancer cells by inhibiting their ability to adhere to the tissue culture plate matrix. Furthermore, some fucoidan extracts inhibited the migration of HCT116 cancer cells from 3D spheroids. Some of our fucoidan extracts also inhibited HCT116 colony formation, demonstrating inhibition of long-term cell survival. The E. maxima water extract also inhibited glucose uptake by HCT116 cells, thereby influencing the glycolytic flux. In conclusion, biologically active fucoidans were successfully extracted from South African brown seaweeds. These fucoidans demonstrated anti-diabetic and anti-cancer properties, revealing their relevance as potential drugs for these diseases. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-10-14
Language Learning Anxiety: a bometric investigation of stress and language learning using wearable devices
- Authors: MacDonald, William Tait
- Date: 2022-10-04
- Subjects: Language and languages Study and teaching Psychological aspects , Wearable technology , Heart rate monitoring , Stress (Psychology) Testing , Anxiety Testing
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/327133 , vital:61084 , DOI 10.21504/10962/327133
- Description: As Sapolsky (2015) notes, stress research has long been characterised by definitional debates that gave rise to a lack of agreement between theorists. An example of this definitional confusion can be seen in the area of Language Learning Anxiety, where there appears to be confusion in the literature over terms such as anxiety and stress. This study investigated the link between stress and language learning using wearable devices measuring heart rate variance, as a means of establishing the feasibility of using this new technology in stress research. The results indicate that the contextualised longitudinal data delivered by wearable devices mitigates against the current dominant paradigm in Language Learning Anxiety, which postulates a straight-line negative correlation between stress and learning. Instead, the inverted U stress relationship proposed by theorists such as Hebb (1955) seem to be a better fit for the data. The nature of the contextualised data generated in this study allowed for comparisons between participants’ stress readings in academic contexts, such as language and non-language classes, and their free time. The findings suggest that certain long-held assumptions about heightened stress in academic contexts may not hold true. While the findings of this study did not reach the levels of statistical significance, they constitute proof of concept that the type of contextualised data delivered by wearable devices may allow for a new type of stress research that incorporates contextualising longitudinal perspectives on participants’ stress levels. In this study the inclusion of contextualising data led to fundamentally different conclusions about the relationship between stress and language learning. The same may be true of many areas of stress research. The findings presented in this study have broader paradigm-altering implications not only for educational policy, but also for stress research in general. Perhaps equally important was that the type of data delivered by wearable devices was qualitatively different from that normally associated with quantitative studies. This presented challenges in data analysis in this study, but also opens intriguing possibilities regarding a means of reconciling the qualitative and quantitative split in research modalities. The use of wearable devices is not without issues, and some of the issues, ranging from practical considerations to ethical conundrums, are presented for the reader’s consideration and to inform future researchers regarding potential pitfalls. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2022
- Full Text:
- Date Issued: 2022-10-04
- Authors: MacDonald, William Tait
- Date: 2022-10-04
- Subjects: Language and languages Study and teaching Psychological aspects , Wearable technology , Heart rate monitoring , Stress (Psychology) Testing , Anxiety Testing
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/327133 , vital:61084 , DOI 10.21504/10962/327133
- Description: As Sapolsky (2015) notes, stress research has long been characterised by definitional debates that gave rise to a lack of agreement between theorists. An example of this definitional confusion can be seen in the area of Language Learning Anxiety, where there appears to be confusion in the literature over terms such as anxiety and stress. This study investigated the link between stress and language learning using wearable devices measuring heart rate variance, as a means of establishing the feasibility of using this new technology in stress research. The results indicate that the contextualised longitudinal data delivered by wearable devices mitigates against the current dominant paradigm in Language Learning Anxiety, which postulates a straight-line negative correlation between stress and learning. Instead, the inverted U stress relationship proposed by theorists such as Hebb (1955) seem to be a better fit for the data. The nature of the contextualised data generated in this study allowed for comparisons between participants’ stress readings in academic contexts, such as language and non-language classes, and their free time. The findings suggest that certain long-held assumptions about heightened stress in academic contexts may not hold true. While the findings of this study did not reach the levels of statistical significance, they constitute proof of concept that the type of contextualised data delivered by wearable devices may allow for a new type of stress research that incorporates contextualising longitudinal perspectives on participants’ stress levels. In this study the inclusion of contextualising data led to fundamentally different conclusions about the relationship between stress and language learning. The same may be true of many areas of stress research. The findings presented in this study have broader paradigm-altering implications not only for educational policy, but also for stress research in general. Perhaps equally important was that the type of data delivered by wearable devices was qualitatively different from that normally associated with quantitative studies. This presented challenges in data analysis in this study, but also opens intriguing possibilities regarding a means of reconciling the qualitative and quantitative split in research modalities. The use of wearable devices is not without issues, and some of the issues, ranging from practical considerations to ethical conundrums, are presented for the reader’s consideration and to inform future researchers regarding potential pitfalls. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2022
- Full Text:
- Date Issued: 2022-10-04
'ORPHEIOI HYMNOI' The generic contexts of the Orphic Hymns
- Malamis, Daniel Scott Christos
- Authors: Malamis, Daniel Scott Christos
- Date: 2022-10-14
- Subjects: Orphic hymns , Poetics Early works to 1800 , Hymns, Greek (Classical) History and criticism , Literary form
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/327177 , vital:61088 , DOI 10.21504/10962/327177
- Description: Uncertainty surrounds the circumstances of Orphic Hymns’ composition and their intended use. Their author has substituted their own identity for that of the mythological poet and there is no certain reference to the extant collection in any ancient source. They are, in this sense, decontextualised. This study aims to make a contribution to the ongoing debate concerning the hymns’ composition, and the original function they might have served, through an analysis of their poetic and generic contexts. Following a detailed survey of scholarship on the hymns, I reflect first on the collection as a unified text, the constitutive parts of the individual hymns and the methods they employ for addressing, describing and praying to the gods. I then study a select group of stylistic features that the hymns prominently display: their use of phonic effects, including etymological figures, of antithesis and symmetrical patterning, and their extensive repetition of poetic formulae. In each case I discuss the deployment and significance of these poetic elements within the collection and consider the intertextual parallels suggested by their recurrence in Greek literary texts of all periods. This analysis reveals the hymns’ engagement with an overlapping set of poetic traditions, including, most prominently, cultic hymns and oracles, gnomic poetry, the theological discourses of the Presocratic philosophers and, in particular, Orphic poetry in its many forms. It suggests moreover that the hymns engage deeply with the oral strategies of the earliest Greek poets, underscoring the conclusion reached by several recent scholars, that the extant collection is essentially performative and was intended to be recited and heard. I argue that the Orphic Hymns were not a unique text in their employment of the stylistic features studied here, but drew extensively upon earlier hymns composed in Orpheus’ name. I further consider, in the light of this argument, the bearing this study has on the unresolved questions of the hymns’ composition, whether by a single author or many, and the aims of the poet(s) who composed them. , Thesis (PhD) -- Faculty of Humanities, School of Languages and Literature Studies, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Malamis, Daniel Scott Christos
- Date: 2022-10-14
- Subjects: Orphic hymns , Poetics Early works to 1800 , Hymns, Greek (Classical) History and criticism , Literary form
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/327177 , vital:61088 , DOI 10.21504/10962/327177
- Description: Uncertainty surrounds the circumstances of Orphic Hymns’ composition and their intended use. Their author has substituted their own identity for that of the mythological poet and there is no certain reference to the extant collection in any ancient source. They are, in this sense, decontextualised. This study aims to make a contribution to the ongoing debate concerning the hymns’ composition, and the original function they might have served, through an analysis of their poetic and generic contexts. Following a detailed survey of scholarship on the hymns, I reflect first on the collection as a unified text, the constitutive parts of the individual hymns and the methods they employ for addressing, describing and praying to the gods. I then study a select group of stylistic features that the hymns prominently display: their use of phonic effects, including etymological figures, of antithesis and symmetrical patterning, and their extensive repetition of poetic formulae. In each case I discuss the deployment and significance of these poetic elements within the collection and consider the intertextual parallels suggested by their recurrence in Greek literary texts of all periods. This analysis reveals the hymns’ engagement with an overlapping set of poetic traditions, including, most prominently, cultic hymns and oracles, gnomic poetry, the theological discourses of the Presocratic philosophers and, in particular, Orphic poetry in its many forms. It suggests moreover that the hymns engage deeply with the oral strategies of the earliest Greek poets, underscoring the conclusion reached by several recent scholars, that the extant collection is essentially performative and was intended to be recited and heard. I argue that the Orphic Hymns were not a unique text in their employment of the stylistic features studied here, but drew extensively upon earlier hymns composed in Orpheus’ name. I further consider, in the light of this argument, the bearing this study has on the unresolved questions of the hymns’ composition, whether by a single author or many, and the aims of the poet(s) who composed them. , Thesis (PhD) -- Faculty of Humanities, School of Languages and Literature Studies, 2022
- Full Text:
- Date Issued: 2022-10-14
Synthesis and evaluation of the medicinal potential of novel 4-hydroxycoumarin derivatives
- Authors: Manyeruke, Meloddy Hlatini
- Date: 2022-04-08
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/164458 , vital:41120 , doi:10.21504/10962/164458
- Description: This research has focused on the synthesis and biological evaluation of a broad range of compounds characterised by the presence of the pharmacologically significant 4-hydroxycoumalin scaffold. The compounds were designed to contain additional pharmachophoric centres to enhance bioactivity and generate lead compounds with dualaction potential. The use of 4-hydroxycoumarin as the primary synthon enabled access to various series of 4-hydroxycoumarin conjugates, the reactive 3-position on the 4-hydroxycoumarin moiety being exploited for regioselective construction of the targeted compounds in several steps. Some of the reactants required in the construction of these compounds were specially synthesised and included propargyloxy benzaldehydes, benzyloxy benzaldehydes and 2,3-dihydroxysuccino-dihydride. Overall, eight different families of novel compounds were accessed, comprising conjugates of 4-hydroxycoumarin with bisethylidenesuccinohyrazide, trifluoroacetamide, amino, benzyloxyphenyl-iminoethyl, benzylidenehyrazinyl-thiazoyl, benzylidenehydrazonoethyl, propargyloxybenzylidenehydrazonoethyl and phenylacryloyl moieties using protocols that required minimal work-up and purification. The eighty novel compounds synthesised in the study were fully characterised using HMRS and advanced NMR techniques. Cytotoxicity, HIV-1 IN and PR inhibitory, and antitrypanosomal, antimalarial and anti-Mtb assays were conducted on the synthesised coumarin derivatives. Several compounds exhibited activity against HIV-1 IN, the most potent being a bis-ethylidenesuccinohyrazide with an IC50 value of 3.5 μM. Various compounds exhibited anti-malarial activity (% pLDH viability in the range 62-77%), anti-trypanosomal activity (the most potent with an IC50 = 0.9 μM against T.b. brucei) and a measure of anti-Mtb activity. Apart from two chalconyl derivatives, none of the synthesised compounds exhibited significant cytotoxicity. Conflicting results were obtained from the in silico docking studies; in some cases supporting the observed in vitro assay data while, in others, exhibiting no correlation. , Thesis (PhD) -- Faculty of Science, Chemistry, 2020
- Full Text:
- Date Issued: 2022-04-08
- Authors: Manyeruke, Meloddy Hlatini
- Date: 2022-04-08
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/164458 , vital:41120 , doi:10.21504/10962/164458
- Description: This research has focused on the synthesis and biological evaluation of a broad range of compounds characterised by the presence of the pharmacologically significant 4-hydroxycoumalin scaffold. The compounds were designed to contain additional pharmachophoric centres to enhance bioactivity and generate lead compounds with dualaction potential. The use of 4-hydroxycoumarin as the primary synthon enabled access to various series of 4-hydroxycoumarin conjugates, the reactive 3-position on the 4-hydroxycoumarin moiety being exploited for regioselective construction of the targeted compounds in several steps. Some of the reactants required in the construction of these compounds were specially synthesised and included propargyloxy benzaldehydes, benzyloxy benzaldehydes and 2,3-dihydroxysuccino-dihydride. Overall, eight different families of novel compounds were accessed, comprising conjugates of 4-hydroxycoumarin with bisethylidenesuccinohyrazide, trifluoroacetamide, amino, benzyloxyphenyl-iminoethyl, benzylidenehyrazinyl-thiazoyl, benzylidenehydrazonoethyl, propargyloxybenzylidenehydrazonoethyl and phenylacryloyl moieties using protocols that required minimal work-up and purification. The eighty novel compounds synthesised in the study were fully characterised using HMRS and advanced NMR techniques. Cytotoxicity, HIV-1 IN and PR inhibitory, and antitrypanosomal, antimalarial and anti-Mtb assays were conducted on the synthesised coumarin derivatives. Several compounds exhibited activity against HIV-1 IN, the most potent being a bis-ethylidenesuccinohyrazide with an IC50 value of 3.5 μM. Various compounds exhibited anti-malarial activity (% pLDH viability in the range 62-77%), anti-trypanosomal activity (the most potent with an IC50 = 0.9 μM against T.b. brucei) and a measure of anti-Mtb activity. Apart from two chalconyl derivatives, none of the synthesised compounds exhibited significant cytotoxicity. Conflicting results were obtained from the in silico docking studies; in some cases supporting the observed in vitro assay data while, in others, exhibiting no correlation. , Thesis (PhD) -- Faculty of Science, Chemistry, 2020
- Full Text:
- Date Issued: 2022-04-08
A critical analysis of the Urban Food System, Urban Governance and Household Food Security in Bulawayo, Zimbabwe
- Authors: Maphosa, Mandlenkosi
- Date: 2022-10-14
- Subjects: Food security Zimbabwe Bulawayo , City planning Government policy Zimbabwe Bulawayo , Urban poor Zimbabwe Bulawayo , Urban agriculture Zimbabwe Bulawayo , COVID-19 (Disease) Zimbabwe Bulawayo , Agent (Philosophy)
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/327165 , vital:61087 , DOI 10.21504/10962/327165
- Description: Urbanisation is occurring on a massive scale globally and even more so in the less developed regions of the Global South including sub-Saharan Africa (SSA). Like other developing regions of the world, urbanisation in SSA is not occurring alongside a corresponding growth in urban economies. Resultantly, it is taking place in tandem with the rising scourge of urban poverty, including food insecurity. While urban food insecurity is a clear challenge in SSA, the challenge has however not been met with equal vigour in policy making and implementation circles and even in academia. Problematically, the urban food security literature often focuses on one element of the food system without giving due attention to other components of the system. Resultantly, broader systemic failures and the dynamics related to the different actors across the system-elements are missed. There has thus been recent calls to embrace urban governance in studying urban food systems, which this study does. The thesis examines the urban food system in Bulawayo (in Zimbabwe) with specific reference to urban governance and household food security to understand sociologically the complex multi-dimensional processes, structures, systems, and practices underpinning the urban food system. As a result of the complex nature of food systems, an eclectic analytical framework is employed encompassing Obeng Odoom’s DED framework, Clapp and Fuchs’ framework of power, Gaventa’s power cube and theories of everyday life derived from de Certeau and Lefebvre. Methodologically, the study is informed by a Critical Realism paradigm which accommodates the convergent mixed methods research design employed. The research strategy employed was that of a survey and case study. Key findings reveal that the Bulawayo food system, from production to consumption, is complex and is nested within broader national and international food systems. Although without a direct and explicit mandate on food security, the local authority is at the centre of urban governance processes as it employs a plethora of strategies to influence the nature of the food system. However, the study reveals that the food system is as much a construction from below through the agential activities of the urban poor. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Maphosa, Mandlenkosi
- Date: 2022-10-14
- Subjects: Food security Zimbabwe Bulawayo , City planning Government policy Zimbabwe Bulawayo , Urban poor Zimbabwe Bulawayo , Urban agriculture Zimbabwe Bulawayo , COVID-19 (Disease) Zimbabwe Bulawayo , Agent (Philosophy)
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/327165 , vital:61087 , DOI 10.21504/10962/327165
- Description: Urbanisation is occurring on a massive scale globally and even more so in the less developed regions of the Global South including sub-Saharan Africa (SSA). Like other developing regions of the world, urbanisation in SSA is not occurring alongside a corresponding growth in urban economies. Resultantly, it is taking place in tandem with the rising scourge of urban poverty, including food insecurity. While urban food insecurity is a clear challenge in SSA, the challenge has however not been met with equal vigour in policy making and implementation circles and even in academia. Problematically, the urban food security literature often focuses on one element of the food system without giving due attention to other components of the system. Resultantly, broader systemic failures and the dynamics related to the different actors across the system-elements are missed. There has thus been recent calls to embrace urban governance in studying urban food systems, which this study does. The thesis examines the urban food system in Bulawayo (in Zimbabwe) with specific reference to urban governance and household food security to understand sociologically the complex multi-dimensional processes, structures, systems, and practices underpinning the urban food system. As a result of the complex nature of food systems, an eclectic analytical framework is employed encompassing Obeng Odoom’s DED framework, Clapp and Fuchs’ framework of power, Gaventa’s power cube and theories of everyday life derived from de Certeau and Lefebvre. Methodologically, the study is informed by a Critical Realism paradigm which accommodates the convergent mixed methods research design employed. The research strategy employed was that of a survey and case study. Key findings reveal that the Bulawayo food system, from production to consumption, is complex and is nested within broader national and international food systems. Although without a direct and explicit mandate on food security, the local authority is at the centre of urban governance processes as it employs a plethora of strategies to influence the nature of the food system. However, the study reveals that the food system is as much a construction from below through the agential activities of the urban poor. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2022
- Full Text:
- Date Issued: 2022-10-14
Exploring the value of an educational partnership within a multilingual pre-school setting
- Authors: Maritz, Anneliese
- Date: 2022-10-04
- Subjects: Early childhood education Parent participation South Africa Eastern Cape , Early childhood teachers Training of , Home and school South Africa Eastern Cape , Parent-teacher relationships South Africa Eastern Cape , Communication and education South Africa Eastern Cape
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/327111 , vital:61082 , DOI 10.21504/10962/327111
- Description: This modest research project was situated in a multilingual Early Childhood Development (ECD) setting in the Eastern Cape (EC) province of South Africa. In the context of high levels of poverty and unemployment in the EC, issues such as under-funding, the nature of the training of practitioners, translating the importance of learning through play into practice, difficulties dealing with diverse cultural practices and the use of multiple languages, all impact ECD provision. Research has shown that parental involvement and creating parent-school partnerships can assist children to progress at school. The overall objectives of this project were to explore how a team in an ECD centre might communicate more effectively with parents and how early stimulation practices in home and school might benefit the child’s development. The theoretical framework draws upon Vygotsky’s (1978) socio-cultural historical theory, Bernstein’s (1971) elaborated and restricted language codes and Bourdieu’s (1977) concepts of social reproduction. A research project in the Netherlands Thuis in School, used an education partnership approach (Iliás et al., 2019). They developed a manual that was adapted for our local context by drawing from the theories mentioned, and to counter the dominant approaches where parenting programs have often been offered from a deficit, narrow perspective. Action Research guided the interventionist approach to workshop sessions, to enable mutual capacity-building of parents and practitioners. To ensure informed consent, participants’ first languages were used. High risk factors related to photographs and videos of participating parents and minor children were successfully addressed. Pre- and post-interviews and workshop data were analysed using template analysis, within a constructivist paradigm. Findings include vignettes to introduce the contexts and parents' ideas prior to the sessions. Then, sessions are summarised as action cycles, with key participants' responses. Finally, post-session evaluations highlight the topics the parents found most meaningful; and parents’ and practitioner accounts of changes in practices. This research illustrates ways that educational partnership elements can influence practice and policy, to improve home and school environments for the benefit of children. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2022
- Full Text:
- Date Issued: 2022-10-04
- Authors: Maritz, Anneliese
- Date: 2022-10-04
- Subjects: Early childhood education Parent participation South Africa Eastern Cape , Early childhood teachers Training of , Home and school South Africa Eastern Cape , Parent-teacher relationships South Africa Eastern Cape , Communication and education South Africa Eastern Cape
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/327111 , vital:61082 , DOI 10.21504/10962/327111
- Description: This modest research project was situated in a multilingual Early Childhood Development (ECD) setting in the Eastern Cape (EC) province of South Africa. In the context of high levels of poverty and unemployment in the EC, issues such as under-funding, the nature of the training of practitioners, translating the importance of learning through play into practice, difficulties dealing with diverse cultural practices and the use of multiple languages, all impact ECD provision. Research has shown that parental involvement and creating parent-school partnerships can assist children to progress at school. The overall objectives of this project were to explore how a team in an ECD centre might communicate more effectively with parents and how early stimulation practices in home and school might benefit the child’s development. The theoretical framework draws upon Vygotsky’s (1978) socio-cultural historical theory, Bernstein’s (1971) elaborated and restricted language codes and Bourdieu’s (1977) concepts of social reproduction. A research project in the Netherlands Thuis in School, used an education partnership approach (Iliás et al., 2019). They developed a manual that was adapted for our local context by drawing from the theories mentioned, and to counter the dominant approaches where parenting programs have often been offered from a deficit, narrow perspective. Action Research guided the interventionist approach to workshop sessions, to enable mutual capacity-building of parents and practitioners. To ensure informed consent, participants’ first languages were used. High risk factors related to photographs and videos of participating parents and minor children were successfully addressed. Pre- and post-interviews and workshop data were analysed using template analysis, within a constructivist paradigm. Findings include vignettes to introduce the contexts and parents' ideas prior to the sessions. Then, sessions are summarised as action cycles, with key participants' responses. Finally, post-session evaluations highlight the topics the parents found most meaningful; and parents’ and practitioner accounts of changes in practices. This research illustrates ways that educational partnership elements can influence practice and policy, to improve home and school environments for the benefit of children. , Thesis (PhD) -- Faculty of Humanities, Psychology, 2022
- Full Text:
- Date Issued: 2022-10-04
Singlet oxygen and optical limiting applications of BODIPYs and other molecular dyes
- Authors: May, Aviwe Khanya
- Date: 2022-04-08
- Subjects: Dyes and dyeing Chemistry , Phthalocyanines , Photochemotherapy , Active oxygen , Nonlinear optics , Time-dependent density functional theory , Photochemistry
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/294618 , vital:57238 , DOI 10.21504/10962/294620
- Description: A series of structurally diverse novel and previously synthesized BODIPY core dyes are synthesized and characterized in this thesis. These BODIPYs were synthesized using 2-methylpyrrole, 2-ethylpyrrole, 2,4-dimethylpyrrole and 3-ethyl-2,4-dimethylpyrrole as the starting pyrroles. The combination of different pyrroles with the same aldehyde results in BODIPY core dyes that are structural analogues. These core dyes were used as precursors to synthesise halogenated BODIPYs and novel styrylBODIPY dyes, which were successfully characterized using FT-IR and 1H NMR spectroscopy. The halogenated BODIPY core dyes and the styrylBODIPY dyes were also characterized using MALDI-TOF mass spectrometry. The introduction of heavy atoms on the BODIPY core leads to a red shift of the main spectral. In the presence of styryl groups, the main spectral band red shifts to the far red end of the visible region. As expected, the halogenated BODIPY core dyes also had moderate singlet oxygen quantum yields. These halogenated core dyes were found to be suitable as photosensitizers as all the dyes reduced bacterial viability to below 50% during photodynamic antimicrobial chemotherapy (PACT) studies against Staphylococcus aureus. The structure-property relationships studied demonstrate that the presence of protons rather than methyls at the 1,7-positions or iodines at the 2,6-positions results in more favorable PACT activity. This is likely to be related to the greater ability of the meso-aryl to rotate into the plane of the dipyrromethene ligand and suggests that there should be a stronger focus on dyes of this type in future studies in this field. During nonlinear optical (NLO) studies, all the styrylBODIPYs exhibited favorable reverse saturable absorption (RSA) responses. In the absence of methyl groups at the 1,7-positions, the meso-aryl ring lies closer to the π-system of the BODIPY core, enhancing donor (D)–π–acceptor (A) properties and resulting in slightly enhanced optical limiting (OL) parameters. Additionally, there is no evidence that the introduction of heavy atoms at the 2,6-positions significantly enhances OL properties. In a similar manner, alkyl substituents at these positions also do not significantly enhance OL properties; this was studied for the first time using 15 with ethyl groups at the 2,6-positions. The combination of z-scan data and transient spectroscopy for 16 demonstrated that the main mechanism responsible for the NLO properties of nonhalogenated BODIPY dyes is one-photon absorption from the ground state followed by ESA in the singlet manifold. From the NLO studies of 25, OL parameters of 1,3,5-tristyrylBODIPY dyes were found to be similar in magnitude to properties of distyrylBODIPY dyes, but to have less favorable optical properties for OL applications. The OL properties of scandium phthalocyanines were assessed for the first time, since the Sc(III) ion, unusually for a first row transition metal ion, is known to readily form sandwich complexes. The presence of a Sc(III) ion does not significantly enhance the OL properties of phthalocyanines relative to those of rare earth metal ions that also form complexes of this type. Because BODIPYs and phthalocyanines typically absorb significantly in the visible region, transparent PBC polymer thin films of disilane-bridged compounds with minimal absorption in this region were studied and exhibited an excellent RSA response. These compounds may be useful in the design of OL materials that can protect the human eye. The optimized geometries and spectroscopic properties of selected BODIPYs were studied. As expected, the presence of bromine, iodine, ethyl and styryl groups at different positions of the BODIPY core leads to a narrowing of the HOMO–LUMO band gap, which results in a red-shift of the main spectral band. Partial atomic charges have also been calculated for some of the styrylBODIPY dyes studied for application in OL, and electrostatic potential energy maps were also visualized to better assess how the dipole moment of BODIPY dyes can be modulated since this can affect the OL properties. For all the BODIPYs studied, the electronegativity of the atoms present influences charge distribution on the BODIPY structure. , Thesis (PhD) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-04-08
- Authors: May, Aviwe Khanya
- Date: 2022-04-08
- Subjects: Dyes and dyeing Chemistry , Phthalocyanines , Photochemotherapy , Active oxygen , Nonlinear optics , Time-dependent density functional theory , Photochemistry
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/294618 , vital:57238 , DOI 10.21504/10962/294620
- Description: A series of structurally diverse novel and previously synthesized BODIPY core dyes are synthesized and characterized in this thesis. These BODIPYs were synthesized using 2-methylpyrrole, 2-ethylpyrrole, 2,4-dimethylpyrrole and 3-ethyl-2,4-dimethylpyrrole as the starting pyrroles. The combination of different pyrroles with the same aldehyde results in BODIPY core dyes that are structural analogues. These core dyes were used as precursors to synthesise halogenated BODIPYs and novel styrylBODIPY dyes, which were successfully characterized using FT-IR and 1H NMR spectroscopy. The halogenated BODIPY core dyes and the styrylBODIPY dyes were also characterized using MALDI-TOF mass spectrometry. The introduction of heavy atoms on the BODIPY core leads to a red shift of the main spectral. In the presence of styryl groups, the main spectral band red shifts to the far red end of the visible region. As expected, the halogenated BODIPY core dyes also had moderate singlet oxygen quantum yields. These halogenated core dyes were found to be suitable as photosensitizers as all the dyes reduced bacterial viability to below 50% during photodynamic antimicrobial chemotherapy (PACT) studies against Staphylococcus aureus. The structure-property relationships studied demonstrate that the presence of protons rather than methyls at the 1,7-positions or iodines at the 2,6-positions results in more favorable PACT activity. This is likely to be related to the greater ability of the meso-aryl to rotate into the plane of the dipyrromethene ligand and suggests that there should be a stronger focus on dyes of this type in future studies in this field. During nonlinear optical (NLO) studies, all the styrylBODIPYs exhibited favorable reverse saturable absorption (RSA) responses. In the absence of methyl groups at the 1,7-positions, the meso-aryl ring lies closer to the π-system of the BODIPY core, enhancing donor (D)–π–acceptor (A) properties and resulting in slightly enhanced optical limiting (OL) parameters. Additionally, there is no evidence that the introduction of heavy atoms at the 2,6-positions significantly enhances OL properties. In a similar manner, alkyl substituents at these positions also do not significantly enhance OL properties; this was studied for the first time using 15 with ethyl groups at the 2,6-positions. The combination of z-scan data and transient spectroscopy for 16 demonstrated that the main mechanism responsible for the NLO properties of nonhalogenated BODIPY dyes is one-photon absorption from the ground state followed by ESA in the singlet manifold. From the NLO studies of 25, OL parameters of 1,3,5-tristyrylBODIPY dyes were found to be similar in magnitude to properties of distyrylBODIPY dyes, but to have less favorable optical properties for OL applications. The OL properties of scandium phthalocyanines were assessed for the first time, since the Sc(III) ion, unusually for a first row transition metal ion, is known to readily form sandwich complexes. The presence of a Sc(III) ion does not significantly enhance the OL properties of phthalocyanines relative to those of rare earth metal ions that also form complexes of this type. Because BODIPYs and phthalocyanines typically absorb significantly in the visible region, transparent PBC polymer thin films of disilane-bridged compounds with minimal absorption in this region were studied and exhibited an excellent RSA response. These compounds may be useful in the design of OL materials that can protect the human eye. The optimized geometries and spectroscopic properties of selected BODIPYs were studied. As expected, the presence of bromine, iodine, ethyl and styryl groups at different positions of the BODIPY core leads to a narrowing of the HOMO–LUMO band gap, which results in a red-shift of the main spectral band. Partial atomic charges have also been calculated for some of the styrylBODIPY dyes studied for application in OL, and electrostatic potential energy maps were also visualized to better assess how the dipole moment of BODIPY dyes can be modulated since this can affect the OL properties. For all the BODIPYs studied, the electronegativity of the atoms present influences charge distribution on the BODIPY structure. , Thesis (PhD) -- Faculty of Science, Chemistry, 2022
- Full Text:
- Date Issued: 2022-04-08
Land use decision-making on residential plots in Fingo Village, Makhanda (Grahamstown), South Africa
- Authors: Memela, Sinenhlanhla
- Date: 2021-04-28
- Subjects: Land use South Africa Makhanda Decision making , Land use, Urban South Africa Makhanda Decision making , Residential real estate South Africa Makhanda , Urban ecology (Sociology) South Africa Makhanda , Urban gardening South Africa Makhanda , Urban livestock production systems South Africa Makhanda
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/322694 , vital:60589 , DOI 10.21504/10962/322694
- Description: This study seeks to understand land use decision-making dynamics on large residential plots in Fingo Village, Makhanda (Grahamstown). Fingo Village was selected as a study area because it is one of the poorest urban settings in South Africa where urban poverty is observed alongside access to land. A dominant economic perspective not only suggests that land use decisions are motivated by economic motives, but also implies that access to land would enable people to generate income from its use to improve their livelihoods. This study argues against an uncritical embrace of this assumption. Lefebvre’s production of space thesis provides a holistic understanding of the factors involved in the making of land use decisions. The focus of this study is on the dialectic process in the spatial triad– spatial practice, representational space and representations of space. This involved the reading of government policies and legislation together with local lived experiences to gain an understanding of the particular spatial practices seen in Fingo Village. Snowball and convenience sampling were used to select 36 household plots in Fingo Village. Primary data was gathered by means of semi-structured interviews and participatory mapping while additional information was sourced from secondary sources and desktop analysis. The findings of the study show that there is no uniform pattern of land use and success. Different land use activities found on the selected residential plots, including the main house, backyard flat or flats, spaza shops, a funeral parlour, livestock keeping, cultural use (a kraal for ancestral worship) and food gardening. These activities are motivated by residents’ perceptions and attitudes towards their spaces, as well as the value and meaning they attach to the land which is not limited to economic factors, but is also influenced by socio-cultural, political and biophysical considerations. Although some spatial practices are prohibited by the government, they are important to the residents. Other participants fail to use the land as would be expected by a conventional economic perspective, due to spatial conflict relating to different interests as a result of collective land ownership and the failure of municipalities to enforce policies and regulations. The fact that numerous factors influence households’ land use decisions means that access to land does not always directly translate into economic benefits. It is all about what people think or do about their land, as well as what the state lays out in terms of policy and legislation, that will influence whether those people with large plots of land will ‘prosper’ or not. , Thesis (PhD) -- Faculty of Science, Geography, 2021
- Full Text:
- Date Issued: 2021-04-28
Land use decision-making on residential plots in Fingo Village, Makhanda (Grahamstown), South Africa
- Authors: Memela, Sinenhlanhla
- Date: 2021-04-28
- Subjects: Land use South Africa Makhanda Decision making , Land use, Urban South Africa Makhanda Decision making , Residential real estate South Africa Makhanda , Urban ecology (Sociology) South Africa Makhanda , Urban gardening South Africa Makhanda , Urban livestock production systems South Africa Makhanda
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/322694 , vital:60589 , DOI 10.21504/10962/322694
- Description: This study seeks to understand land use decision-making dynamics on large residential plots in Fingo Village, Makhanda (Grahamstown). Fingo Village was selected as a study area because it is one of the poorest urban settings in South Africa where urban poverty is observed alongside access to land. A dominant economic perspective not only suggests that land use decisions are motivated by economic motives, but also implies that access to land would enable people to generate income from its use to improve their livelihoods. This study argues against an uncritical embrace of this assumption. Lefebvre’s production of space thesis provides a holistic understanding of the factors involved in the making of land use decisions. The focus of this study is on the dialectic process in the spatial triad– spatial practice, representational space and representations of space. This involved the reading of government policies and legislation together with local lived experiences to gain an understanding of the particular spatial practices seen in Fingo Village. Snowball and convenience sampling were used to select 36 household plots in Fingo Village. Primary data was gathered by means of semi-structured interviews and participatory mapping while additional information was sourced from secondary sources and desktop analysis. The findings of the study show that there is no uniform pattern of land use and success. Different land use activities found on the selected residential plots, including the main house, backyard flat or flats, spaza shops, a funeral parlour, livestock keeping, cultural use (a kraal for ancestral worship) and food gardening. These activities are motivated by residents’ perceptions and attitudes towards their spaces, as well as the value and meaning they attach to the land which is not limited to economic factors, but is also influenced by socio-cultural, political and biophysical considerations. Although some spatial practices are prohibited by the government, they are important to the residents. Other participants fail to use the land as would be expected by a conventional economic perspective, due to spatial conflict relating to different interests as a result of collective land ownership and the failure of municipalities to enforce policies and regulations. The fact that numerous factors influence households’ land use decisions means that access to land does not always directly translate into economic benefits. It is all about what people think or do about their land, as well as what the state lays out in terms of policy and legislation, that will influence whether those people with large plots of land will ‘prosper’ or not. , Thesis (PhD) -- Faculty of Science, Geography, 2021
- Full Text:
- Date Issued: 2021-04-28
Characterisation of two novel ferrocenyl benzoxazines as in vitro triple-negative breast cancer inhibitors
- Authors: Mhlanga, Richwell
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365689 , vital:65776
- Description: Thesis access embargoed. Expected released date early 2025. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Mhlanga, Richwell
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365689 , vital:65776
- Description: Thesis access embargoed. Expected released date early 2025. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2022
- Full Text:
- Date Issued: 2022-10-14