Physicochemical properties and photodynamic therapy activities of indium and zinc phthalocyanine-nanoparticle conjugates
- Authors: Dube, Edith
- Date: 2019
- Subjects: Indium , Zinc , Phthalocyanines , Breast -- Cancer -- Photochemotherapy , Nanoparticles
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76506 , vital:30589
- Description: The syntheses and characterization of symmetric and asymmetric Pcs functionalized at the peripheral position are reported. The Pcs contain either zinc or indium as central metals and have carboxyphenoxy, phenoxy propanoic acid, benzothiazole phenoxy, thiophine ethoxy or di-O-isopropylidene-α-D-glucopyranose as ring substituents. The Pcs were linked to NPs via an amide bond or through self-assembly. The photophysics and photochemistry of the Pcs were assessed when alone and with conjugates. All the studied Pcs showed good photophysicochemical behaviour with relatively high triplet and singlet oxygen quantum yields corresponding to their low fluorescence quantum yield. The Pcs with indium in their central cavity exhibited higher triplet and singlet oxygen quantum yields in comparison to their zinc counterparts due to the heavy–atom effect obtained from the former. Asymmetrical Pcs displayed higher triplet and singlet oxygen quantum yields than their symmetrical counterparts. The triplet quantum yield, generally increased on linkage to nanoparticles (NPs) due to the heavy–atom effect of gold and silver in NPs. The conjugates to gold nanospheres yielded higher triplet and singlet quantum yields than their gold nanotriangles counterparts due to the higher loading by the former probably encouraged by their relatively small particle size. The in vitro dark cytotoxicity and photodynamic therapy of selected Pc complexes and conjugates against MCF-7 cells was tested. All studied Pc complexes and conjugates showed minimum dark toxicity making them applicable for PDT. All complexes displayed poor phototoxicity with >50Îll viability at concentrations≤ 160μg/mL, however the conjugates showed<50% cell viabilityatconcentrations≤ 160μg/mLprobably due to the enhanced singlet oxygen quantum yield. The findings from this work show the importance of linking photosensitises such as phthalocyanines to metal nanoparticles for the enhancement ofsinglet oxygen quantum yield and ultimately the photodynamic effect.
- Full Text:
- Date Issued: 2019
- Authors: Dube, Edith
- Date: 2019
- Subjects: Indium , Zinc , Phthalocyanines , Breast -- Cancer -- Photochemotherapy , Nanoparticles
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76506 , vital:30589
- Description: The syntheses and characterization of symmetric and asymmetric Pcs functionalized at the peripheral position are reported. The Pcs contain either zinc or indium as central metals and have carboxyphenoxy, phenoxy propanoic acid, benzothiazole phenoxy, thiophine ethoxy or di-O-isopropylidene-α-D-glucopyranose as ring substituents. The Pcs were linked to NPs via an amide bond or through self-assembly. The photophysics and photochemistry of the Pcs were assessed when alone and with conjugates. All the studied Pcs showed good photophysicochemical behaviour with relatively high triplet and singlet oxygen quantum yields corresponding to their low fluorescence quantum yield. The Pcs with indium in their central cavity exhibited higher triplet and singlet oxygen quantum yields in comparison to their zinc counterparts due to the heavy–atom effect obtained from the former. Asymmetrical Pcs displayed higher triplet and singlet oxygen quantum yields than their symmetrical counterparts. The triplet quantum yield, generally increased on linkage to nanoparticles (NPs) due to the heavy–atom effect of gold and silver in NPs. The conjugates to gold nanospheres yielded higher triplet and singlet quantum yields than their gold nanotriangles counterparts due to the higher loading by the former probably encouraged by their relatively small particle size. The in vitro dark cytotoxicity and photodynamic therapy of selected Pc complexes and conjugates against MCF-7 cells was tested. All studied Pc complexes and conjugates showed minimum dark toxicity making them applicable for PDT. All complexes displayed poor phototoxicity with >50Îll viability at concentrations≤ 160μg/mL, however the conjugates showed<50% cell viabilityatconcentrations≤ 160μg/mLprobably due to the enhanced singlet oxygen quantum yield. The findings from this work show the importance of linking photosensitises such as phthalocyanines to metal nanoparticles for the enhancement ofsinglet oxygen quantum yield and ultimately the photodynamic effect.
- Full Text:
- Date Issued: 2019
Physiological and mechanistic characteristics of all-out running using the critical speed concept
- Authors: Kramer, Mark
- Date: 2019
- Subjects: Aerobic exercises , Physical fitness Running Exercise
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/40511 , vital:36178
- Description: The studies described in this thesis, as far as could be ascertained, were the first to investigate the physiological and mechanistic characteristics of all-out running using the critical speed concept specifically applied to field-sport athletes. In the first study the oxygen uptake (𝑉̇𝑂2) kinetics of linear and shuttle all-out running were investigated. The 𝑉̇𝑂2 kinetic parameters were also related to parameters derived from a graded exercise test. No differences were observed in all 𝑉̇ 𝑂2 kinetic parameters between all-out linear and shuttle running, even though differences in all-out testing parameters were evident. The study was novel in that it was, as far as could be ascertained, the first to implement and investigate differences in 𝑉̇𝑂2 kinetics applied to all-out running. The second study investigated whether the parameters derived from all-out linear and shuttle running were representative of aerobic fitness, and the extent to which the all-out test (AOT) related to already established evaluations of aerobic fitness (e.g., graded exercise test [GXT] and the Yo-Yo intermittent recovery test [YYIR1]). It was also investigated whether the parameters from the AOTs could be used to predict the time to completion (tLIM) of shuttle-based performances. The outcomes of this study showed that both the linear and 50-m AOTs were indeed valid for the aerobic assessment of fitness by showing high correlations with maximal pulmonary oxygen uptake (𝑉̇𝑂2𝑚𝑎𝑥). Both the linear and 50-m AOT could therefore be used as surrogates for the evaluation of aerobic fitness. Interestingly, in terms of the tLIM prediction, the 25-m AOT showed the greatest utility. This study was novel on several fronts in that it was the first to: (1) investigate the physiological link between linear and shuttle AOTs and the GXT, (2) investigate the difference between AOTs and the YYIR1, and (3) investigate the application of the AOT methodology to field-based athletes such as rugby players. The third study investigated the energetic cost (EC) of locomotion as well as the metabolic power (𝑃̇) required to run at given speeds. The energetic approach provides a more robust evaluation of the differences between linear and shuttle running due to the all-out nature of the tests. Conventional methods of energy assessment often fall short due to the preclusion of a physiological steady-state, hence requiring more robust mathematical models to evaluate all-out running performance. The results of this study showed that differences between linear and shuttle AOTs are more likely neuromuscular as opposed to physiological. Peak EC and 𝑃̇ were significantly greater for shuttle running compared to linear running, showing clear non-linear increases with each successive increase in running speed. However, the mean EC and 𝑃̇ were not different, showing that all-out shuttle running ‘balances’ the lower running speeds (implying a lower physiological load compared to linear running) with the higher metabolic load imposed by the intense directional changes. This study was novel as it was, as far as could be ascertained, the first to apply the energetic approach to all-out running as well as investigate the differences in energetics between linear and shuttle AOTs. The fourth study provided a means by which the speed-time characteristics of all-out running could be objectively quantified. A novel bi-exponential model was applied to both the linear and shuttle speed-time curves and allowed various mechanistic aspects of the speed-time curve to be characterized. Conventional assessment of the AOT allows for the derivation of only two key parameters, namely critical speed (CS) and the finite distance achievable at speeds exceeding CS (D’). The application of the bi-exponential model expands the number of useful parameters that can be derived from an AOT to seven. The additional useful parameters include: maximum speed [𝑆𝑚𝑎𝑥], time to maximum speed [𝑡𝑐], amplitude of the difference between 𝑆𝑚𝑎𝑥 and CS [𝐴𝑑], curvature constant of the exponential decay [𝜏𝑑] and the asymptote of the exponential decay function [𝑆0], fatigue index showing the percent decline between 𝑆𝑚𝑎𝑥 and CS [FI%], and the finite capacity for running at speeds exceeding CS [D’; representing the area under the curve that is above CS]. The CS and D’ parameters derived from the bi-exponential model were not different to the CS and D’ parameters derived using the conventional method of analysis, thereby showing that the bi-exponential model is a valid means of assessing the curvature characteristics of the AOT, as well as providing additional information that cannot be gleaned from the traditional approach.
- Full Text:
- Date Issued: 2019
- Authors: Kramer, Mark
- Date: 2019
- Subjects: Aerobic exercises , Physical fitness Running Exercise
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/40511 , vital:36178
- Description: The studies described in this thesis, as far as could be ascertained, were the first to investigate the physiological and mechanistic characteristics of all-out running using the critical speed concept specifically applied to field-sport athletes. In the first study the oxygen uptake (𝑉̇𝑂2) kinetics of linear and shuttle all-out running were investigated. The 𝑉̇𝑂2 kinetic parameters were also related to parameters derived from a graded exercise test. No differences were observed in all 𝑉̇ 𝑂2 kinetic parameters between all-out linear and shuttle running, even though differences in all-out testing parameters were evident. The study was novel in that it was, as far as could be ascertained, the first to implement and investigate differences in 𝑉̇𝑂2 kinetics applied to all-out running. The second study investigated whether the parameters derived from all-out linear and shuttle running were representative of aerobic fitness, and the extent to which the all-out test (AOT) related to already established evaluations of aerobic fitness (e.g., graded exercise test [GXT] and the Yo-Yo intermittent recovery test [YYIR1]). It was also investigated whether the parameters from the AOTs could be used to predict the time to completion (tLIM) of shuttle-based performances. The outcomes of this study showed that both the linear and 50-m AOTs were indeed valid for the aerobic assessment of fitness by showing high correlations with maximal pulmonary oxygen uptake (𝑉̇𝑂2𝑚𝑎𝑥). Both the linear and 50-m AOT could therefore be used as surrogates for the evaluation of aerobic fitness. Interestingly, in terms of the tLIM prediction, the 25-m AOT showed the greatest utility. This study was novel on several fronts in that it was the first to: (1) investigate the physiological link between linear and shuttle AOTs and the GXT, (2) investigate the difference between AOTs and the YYIR1, and (3) investigate the application of the AOT methodology to field-based athletes such as rugby players. The third study investigated the energetic cost (EC) of locomotion as well as the metabolic power (𝑃̇) required to run at given speeds. The energetic approach provides a more robust evaluation of the differences between linear and shuttle running due to the all-out nature of the tests. Conventional methods of energy assessment often fall short due to the preclusion of a physiological steady-state, hence requiring more robust mathematical models to evaluate all-out running performance. The results of this study showed that differences between linear and shuttle AOTs are more likely neuromuscular as opposed to physiological. Peak EC and 𝑃̇ were significantly greater for shuttle running compared to linear running, showing clear non-linear increases with each successive increase in running speed. However, the mean EC and 𝑃̇ were not different, showing that all-out shuttle running ‘balances’ the lower running speeds (implying a lower physiological load compared to linear running) with the higher metabolic load imposed by the intense directional changes. This study was novel as it was, as far as could be ascertained, the first to apply the energetic approach to all-out running as well as investigate the differences in energetics between linear and shuttle AOTs. The fourth study provided a means by which the speed-time characteristics of all-out running could be objectively quantified. A novel bi-exponential model was applied to both the linear and shuttle speed-time curves and allowed various mechanistic aspects of the speed-time curve to be characterized. Conventional assessment of the AOT allows for the derivation of only two key parameters, namely critical speed (CS) and the finite distance achievable at speeds exceeding CS (D’). The application of the bi-exponential model expands the number of useful parameters that can be derived from an AOT to seven. The additional useful parameters include: maximum speed [𝑆𝑚𝑎𝑥], time to maximum speed [𝑡𝑐], amplitude of the difference between 𝑆𝑚𝑎𝑥 and CS [𝐴𝑑], curvature constant of the exponential decay [𝜏𝑑] and the asymptote of the exponential decay function [𝑆0], fatigue index showing the percent decline between 𝑆𝑚𝑎𝑥 and CS [FI%], and the finite capacity for running at speeds exceeding CS [D’; representing the area under the curve that is above CS]. The CS and D’ parameters derived from the bi-exponential model were not different to the CS and D’ parameters derived using the conventional method of analysis, thereby showing that the bi-exponential model is a valid means of assessing the curvature characteristics of the AOT, as well as providing additional information that cannot be gleaned from the traditional approach.
- Full Text:
- Date Issued: 2019
Plants, people, and place: complex, mutualistic, and co-evolving global patterns through time
- Authors: Van Wijk, Yvette Ethné
- Date: 2019
- Subjects: Ethnobotany -- South Africa -- Western Cape , Khoisan (African people) -- Ethnobotany , Human-plant relationships -- South Africa -- Western Cape , Plants -- Classification -- South Africa -- Western Cape , Plant remains (Archaeology) -- South Africa -- Western Cape , Ethnoscience -- South Africa -- Western Cape , Regression analysis
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76575 , vital:30609
- Description: My thesis studies and analyses the suite of distinctive plant taxa which persist in small patches of vegetation growing in close association with archaeological habitation sites in the southern Cape, South Africa. The unexpected correlation and overlap between botanical taxa collected at 75 site complexes, and ethnobotanical data collected in collaboration with modern Khoi-San communities in the same area, is explored and interrogated. Although sparse, reports of the same suite of taxa recovered from archaeological excavations in the Cape provinces provides depth of time to the study, linking the past to the present. The three-way correlation of a suite of plants closely associated with humans and habitation sites through time, allows for triangulation of the data in order to validate and cross verify the results using more than one frame of reference. Both the plants and the knowledge about their uses have persisted in spite of historical attrition, and alienation of land and language, suffered by the Khoi-San over the past 300 years. Drawing on a large body of primary and secondary data, and using an interdisciplinary, abductive and pragmatic mixed methods approach, a pattern can be traced throughout Africa and globally. Regression analysis strongly indicates that the most ubiquitous taxa were selected for a purpose and are not randomly present in association with humans. Botanical, anthropological, and archaeological studies seldom focus on the inter-connectedness of people and plants at the sites they inhabited. Very little research into modern vegetation in close association with the sites has been undertaken, and vegetation mapping has not captured the occurrence of these site-specific small vegetation patches recorded during my surveys. The topographically, geologically, and vegetatively complex and varied southern Cape, and greater Cape area, is extremely rich in archaeological sites and history. This study suggests that the value of site-specific plant taxa to humans throughout the aeons of pre-agricultural history, persists into the present. Due to tolerance of a broad range of climatic and environmental variables, there is value in the study of these ancient and neglected useful plants in the face of climate change. That this vegetation is so closely associated with archaeological sites of cultural and historic importance confers an urgency to recognising the existence and significance of the distinctive and possibly anthropogenic vegetation surrounding the sites.
- Full Text:
- Date Issued: 2019
- Authors: Van Wijk, Yvette Ethné
- Date: 2019
- Subjects: Ethnobotany -- South Africa -- Western Cape , Khoisan (African people) -- Ethnobotany , Human-plant relationships -- South Africa -- Western Cape , Plants -- Classification -- South Africa -- Western Cape , Plant remains (Archaeology) -- South Africa -- Western Cape , Ethnoscience -- South Africa -- Western Cape , Regression analysis
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76575 , vital:30609
- Description: My thesis studies and analyses the suite of distinctive plant taxa which persist in small patches of vegetation growing in close association with archaeological habitation sites in the southern Cape, South Africa. The unexpected correlation and overlap between botanical taxa collected at 75 site complexes, and ethnobotanical data collected in collaboration with modern Khoi-San communities in the same area, is explored and interrogated. Although sparse, reports of the same suite of taxa recovered from archaeological excavations in the Cape provinces provides depth of time to the study, linking the past to the present. The three-way correlation of a suite of plants closely associated with humans and habitation sites through time, allows for triangulation of the data in order to validate and cross verify the results using more than one frame of reference. Both the plants and the knowledge about their uses have persisted in spite of historical attrition, and alienation of land and language, suffered by the Khoi-San over the past 300 years. Drawing on a large body of primary and secondary data, and using an interdisciplinary, abductive and pragmatic mixed methods approach, a pattern can be traced throughout Africa and globally. Regression analysis strongly indicates that the most ubiquitous taxa were selected for a purpose and are not randomly present in association with humans. Botanical, anthropological, and archaeological studies seldom focus on the inter-connectedness of people and plants at the sites they inhabited. Very little research into modern vegetation in close association with the sites has been undertaken, and vegetation mapping has not captured the occurrence of these site-specific small vegetation patches recorded during my surveys. The topographically, geologically, and vegetatively complex and varied southern Cape, and greater Cape area, is extremely rich in archaeological sites and history. This study suggests that the value of site-specific plant taxa to humans throughout the aeons of pre-agricultural history, persists into the present. Due to tolerance of a broad range of climatic and environmental variables, there is value in the study of these ancient and neglected useful plants in the face of climate change. That this vegetation is so closely associated with archaeological sites of cultural and historic importance confers an urgency to recognising the existence and significance of the distinctive and possibly anthropogenic vegetation surrounding the sites.
- Full Text:
- Date Issued: 2019
Pragmatics teaching: on the development of learners’ linguistic competence among selected East London District schools
- Authors: Myoli, Ndileka
- Date: 2019
- Subjects: Pragmatics -- Study and teaching Language and languages -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/11232 , vital:37607
- Description: South Africa was listed amongst the countries with a percentage of students with achievement too low for estimation by “Progress International Results in Reading” in 2011. Meanwhile, there was also an indication that, high school learners in the Eastern Cape Province are highly challenged, as far as their ability to produce speech, as well as the ability to interpret meaning beyond what is literally suggested. Since such difficulties usually pose problems of content understanding, concerned researchers in the field of language took it upon themselves to investigate the underlying cause of the problem, in order to prevent more problems of pragmatics incompetence, such as, problems with social interaction that could retard one’s ability to function independently as an adult. While many studies have been conducted in the area of Pragmatics language competence, this study found it necessary to contribute around this debate. Since the study was two-fold, isiXhosa Home language learners of Grades 10 to 12 were investigated with an objective to determine the extent of pragmatic incompetence and the Teachers were investigated to determine the effectiveness of their teaching of pragmatics language. A number of 108 high school isiXhosa learners, of ages of between 16 and 18 years, from East London Directorate, 36 per Grade, from the three selected schools high schools, were sampled, 36 consisting of 18 males and 18 females per grade from each selected high school. 9 isiXhosa Home Language teachers of between the ages of 45 to 54 years were sampled from the selected schools. This study used an assessment test for the learners and the questionnaire for the teachers, as a means of data collection techniques. The study applied a high consideration of validity as well as of ethical matters in order to ensure the reliability of results. The study found that, isiXhosa Home language learners’ levels of pragmatic competence are high and with the appropriate use of good methods of pragmatics language teaching, learners’ pragmatics competence can develop.This study will be able to encourage syllabus designers to collaborate with subject teachers, beginning right at the inception of the syllabus planning. IsiXhosa language teachers can develop teaching material appropriate for their primary goal, which is the development of pragmatic competence. Further research is recommended to investigate more around this area of study to a point where isiXhosa Home language can be counted amongst the great and valued languages of South Africa.
- Full Text:
- Date Issued: 2019
- Authors: Myoli, Ndileka
- Date: 2019
- Subjects: Pragmatics -- Study and teaching Language and languages -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/11232 , vital:37607
- Description: South Africa was listed amongst the countries with a percentage of students with achievement too low for estimation by “Progress International Results in Reading” in 2011. Meanwhile, there was also an indication that, high school learners in the Eastern Cape Province are highly challenged, as far as their ability to produce speech, as well as the ability to interpret meaning beyond what is literally suggested. Since such difficulties usually pose problems of content understanding, concerned researchers in the field of language took it upon themselves to investigate the underlying cause of the problem, in order to prevent more problems of pragmatics incompetence, such as, problems with social interaction that could retard one’s ability to function independently as an adult. While many studies have been conducted in the area of Pragmatics language competence, this study found it necessary to contribute around this debate. Since the study was two-fold, isiXhosa Home language learners of Grades 10 to 12 were investigated with an objective to determine the extent of pragmatic incompetence and the Teachers were investigated to determine the effectiveness of their teaching of pragmatics language. A number of 108 high school isiXhosa learners, of ages of between 16 and 18 years, from East London Directorate, 36 per Grade, from the three selected schools high schools, were sampled, 36 consisting of 18 males and 18 females per grade from each selected high school. 9 isiXhosa Home Language teachers of between the ages of 45 to 54 years were sampled from the selected schools. This study used an assessment test for the learners and the questionnaire for the teachers, as a means of data collection techniques. The study applied a high consideration of validity as well as of ethical matters in order to ensure the reliability of results. The study found that, isiXhosa Home language learners’ levels of pragmatic competence are high and with the appropriate use of good methods of pragmatics language teaching, learners’ pragmatics competence can develop.This study will be able to encourage syllabus designers to collaborate with subject teachers, beginning right at the inception of the syllabus planning. IsiXhosa language teachers can develop teaching material appropriate for their primary goal, which is the development of pragmatic competence. Further research is recommended to investigate more around this area of study to a point where isiXhosa Home language can be counted amongst the great and valued languages of South Africa.
- Full Text:
- Date Issued: 2019
Pyramidal deliberative democracy
- Authors: Danielsen, James
- Date: 2019
- Subjects: Democracy , Information technology -- Political aspects , Internet in public administration , Political participation -- Computer network resources , World politics
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/74502 , vital:30309
- Description: This dissertation has two main objectives. First, to outline an ICT-facilitated model of democracy called ‘pyramidal democracy’ that reconciles deliberative democracy with mass engagement. Second, to suggest how this model of democracy might engender the democratisation of the global economy and thus the provision of a basic level of economic security for all global citizens. At the core of the model is the pyramidal deliberative network, a means of organising citizens into small online deliberative groups and linking these groups together by means of an iterative process of delegate-selection and group-formation. The pyramidal network enables citizens to aggregate their preferences in a deliberative manner, and then project social power by authorizing the delegates at the top-tier of the pyramidal network to communicate their social demands to elected officials or to other points of authority. The envisioned outcome is the democratisation of the public sphere by means of the proliferation of deliberative networks in the government, market, and civil society spheres. Transnational pyramidal networks may make it feasible to instantiate a new citizen-based schema of global governance and, thereby, facilitate the reform of the United Nations and enable a transition towards global peace, sustainability, and distributive justice. Distributive justice might be achieved by means of implementing the six components of a democratised economy: participatory budgeting, fee-and-dividend taxes, a basic income, monetary reform, workplace democracy, and the sharing economy. Taken together, these components might enable the universal provision of a social minimum – a universal basic income sufficient for basic security and real freedom. Taken to its logical conclusion, a democratised economy may also enable a transition towards a post-scarcity economic order characterised by a maximal stock of humanmade and natural capital that would not exceed the sustainable carrying capacity of the earth.
- Full Text:
- Date Issued: 2019
- Authors: Danielsen, James
- Date: 2019
- Subjects: Democracy , Information technology -- Political aspects , Internet in public administration , Political participation -- Computer network resources , World politics
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/74502 , vital:30309
- Description: This dissertation has two main objectives. First, to outline an ICT-facilitated model of democracy called ‘pyramidal democracy’ that reconciles deliberative democracy with mass engagement. Second, to suggest how this model of democracy might engender the democratisation of the global economy and thus the provision of a basic level of economic security for all global citizens. At the core of the model is the pyramidal deliberative network, a means of organising citizens into small online deliberative groups and linking these groups together by means of an iterative process of delegate-selection and group-formation. The pyramidal network enables citizens to aggregate their preferences in a deliberative manner, and then project social power by authorizing the delegates at the top-tier of the pyramidal network to communicate their social demands to elected officials or to other points of authority. The envisioned outcome is the democratisation of the public sphere by means of the proliferation of deliberative networks in the government, market, and civil society spheres. Transnational pyramidal networks may make it feasible to instantiate a new citizen-based schema of global governance and, thereby, facilitate the reform of the United Nations and enable a transition towards global peace, sustainability, and distributive justice. Distributive justice might be achieved by means of implementing the six components of a democratised economy: participatory budgeting, fee-and-dividend taxes, a basic income, monetary reform, workplace democracy, and the sharing economy. Taken together, these components might enable the universal provision of a social minimum – a universal basic income sufficient for basic security and real freedom. Taken to its logical conclusion, a democratised economy may also enable a transition towards a post-scarcity economic order characterised by a maximal stock of humanmade and natural capital that would not exceed the sustainable carrying capacity of the earth.
- Full Text:
- Date Issued: 2019
Reading to learn for secondary schooling: an interventionist action research study within a South African under-privileged setting
- Authors: Mataka, Tawanda Wallace
- Date: 2019
- Subjects: Rose, David, 1955-. Reading to learn , Reading (Secondary) , English language -- Study and teaching (Secondary) -- Foreign speakers -- South Africa , English language -- Study and teaching (Secondary) -- Foreign speakers -- South Africa -- Case studies , Literacy -- South Africa -- Makhanda
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92191 , vital:30706
- Description: The study examined the contribution that Rose’s (2005) Reading to Learn (RtL) methodology made in development of advanced literacy abilities recommended in the schooling system. RtL was influenced by Bernstein’s theory of pedagogic discourse, Bruner, Vygotsky’s social learning theory and Halliday’s systemic functional linguistics theory. The study used the same cohort of learners during Grades 11 and 12 in a black township secondary school in Grahamstown, Eastern Cape, South Africa. RtL was birthed in Australia with the intention of accelerating literacy development of learners in disadvantaged communities. Based on its success in Australia, I implemented the methodology against a backdrop of continuously declining literacy standards in South African primary and secondary schools. Researchers on literacy acknowledge that socioeconomic and geosocial circumstances cannot be divorced from poor literacy performances in South African schools. Although these two factors play a role in regressing literacy, pedagogical approaches play a role. RtL was employed as an intervention strategy with learners whose literacy abilities were found lacking in comparison to curriculum demands. Despite the focus being on learners whose performance was below expected academic levels, the able learners were motivated to further their advanced abilities. The learners whose performance was previously compromised performed to par with their able counterparts. RtL provided all learners an opportunity to apply, with less difficulty, the language approved by the schooling system. The two research questions sought to illuminate the role RtL played in developing learners’ ability to read, so that they could converse with text and put into writing practice what they had read. In this regard, creative and transactional assignments were written, and performance assessed to evaluate the RtL intervention. Secondly, the research allowed me to get an insight through interviews with learners as to how they were positively or negatively influenced through RtL in learning English as a First Additional Language. The study was a longitudinal action research study which had a life span of 22 months. It was dominantly qualitative with a thin quantitative strand. Data to evaluate effectiveness was generated from learners’ written work and interviews. The learners’ work was analysed using an RtL assessment tool adopted from Rose (2018), for the purposes of uniformity and reliability. Findings from interviews highlighted various views regarding the positive impact of RtL. What emerged from the findings is a reflection of the positive impact RtL had on literacy development. Significantly, learners’ work improved across the board, true to Rose’s assertion that learners exposed to teaching using RtL principles experience accelerated literacy development. Based on these findings, RtL implemented in a township setting in South Africa yields results similar to those in Australia and other countries.
- Full Text:
- Date Issued: 2019
- Authors: Mataka, Tawanda Wallace
- Date: 2019
- Subjects: Rose, David, 1955-. Reading to learn , Reading (Secondary) , English language -- Study and teaching (Secondary) -- Foreign speakers -- South Africa , English language -- Study and teaching (Secondary) -- Foreign speakers -- South Africa -- Case studies , Literacy -- South Africa -- Makhanda
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92191 , vital:30706
- Description: The study examined the contribution that Rose’s (2005) Reading to Learn (RtL) methodology made in development of advanced literacy abilities recommended in the schooling system. RtL was influenced by Bernstein’s theory of pedagogic discourse, Bruner, Vygotsky’s social learning theory and Halliday’s systemic functional linguistics theory. The study used the same cohort of learners during Grades 11 and 12 in a black township secondary school in Grahamstown, Eastern Cape, South Africa. RtL was birthed in Australia with the intention of accelerating literacy development of learners in disadvantaged communities. Based on its success in Australia, I implemented the methodology against a backdrop of continuously declining literacy standards in South African primary and secondary schools. Researchers on literacy acknowledge that socioeconomic and geosocial circumstances cannot be divorced from poor literacy performances in South African schools. Although these two factors play a role in regressing literacy, pedagogical approaches play a role. RtL was employed as an intervention strategy with learners whose literacy abilities were found lacking in comparison to curriculum demands. Despite the focus being on learners whose performance was below expected academic levels, the able learners were motivated to further their advanced abilities. The learners whose performance was previously compromised performed to par with their able counterparts. RtL provided all learners an opportunity to apply, with less difficulty, the language approved by the schooling system. The two research questions sought to illuminate the role RtL played in developing learners’ ability to read, so that they could converse with text and put into writing practice what they had read. In this regard, creative and transactional assignments were written, and performance assessed to evaluate the RtL intervention. Secondly, the research allowed me to get an insight through interviews with learners as to how they were positively or negatively influenced through RtL in learning English as a First Additional Language. The study was a longitudinal action research study which had a life span of 22 months. It was dominantly qualitative with a thin quantitative strand. Data to evaluate effectiveness was generated from learners’ written work and interviews. The learners’ work was analysed using an RtL assessment tool adopted from Rose (2018), for the purposes of uniformity and reliability. Findings from interviews highlighted various views regarding the positive impact of RtL. What emerged from the findings is a reflection of the positive impact RtL had on literacy development. Significantly, learners’ work improved across the board, true to Rose’s assertion that learners exposed to teaching using RtL principles experience accelerated literacy development. Based on these findings, RtL implemented in a township setting in South Africa yields results similar to those in Australia and other countries.
- Full Text:
- Date Issued: 2019
Reflection and representation: modes of communicating Zimbabwean historical narratives through popular music
- Authors: Gwindingwe, Gift
- Date: 2019
- Subjects: Communication Interpersonal communication
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15804 , vital:40528
- Description: Music, before and after independence in the former colonies, has been playing a central role of articulating national concerns. It became an alternative medium through which historical narratives were channeled out to the public. While many scholars have acknowledged the critical role of music’s attempt to whip the autocratic governments into line, and the attempts by the governments across the world to thwart the critical/activism role of music, little emphasis was put on the mechanism of circumventing censorship, the linguistic competence (or lack of it) of music in conscientising the public on national issues. This thesis aims to harness this seemingly entertainment tool (music) into serious academic discourse by looking at the way power relations and ideological contestations are symbolically reflected, represented and communicated in popular culture, in particular the Zimbabwean Sungura and Chimurenga music. It makes a critical analysis of the diction of music as it attempts (or fails to) reflect and represent the Zimbabwean historical narratives from the early 1990s to 2008. The study tries to (semiologically) fracture the musical lexicon and the ideological stance on which it is based to show the extent to which music communicates by way of reflecting and representing the Zimbabwean historical narratives. The thesis looks at how popular music has ‘become the most prominent signifier’ and at ‘the shifting meanings and the significance of … music’ (Nooshin 2005:231) in Zimbabwe. It utilises a qualitative research approach specifically an interpretive prism. Key research methods for the study include in-depth semi-structured interviews which were conducted with purposively selected informants such as university academics and two of the selected musicians. The selected academics were purposively sampled basing on the researcher’s knowledge of their inclination towards Cultural Studies, particularly popular culture. The study has managed to bring clarity to the research questions in a big way considering the application of the various theories that framed the thesis discussion. Research findings indicate that interpretive semiotics aids to unpack the philosophy of meaning making through song. Music as a medium has the reflective effect of a mirror and a photographic effect of a camera to enunciate the ideological innuendo in the leader-led dichotomy. The study shows that protest popular music rejects knowledge that affirms the status quo; it is counter hegemonic and seeks to regenerate selfhoods and self-liberation amongst the subaltern class.
- Full Text:
- Date Issued: 2019
- Authors: Gwindingwe, Gift
- Date: 2019
- Subjects: Communication Interpersonal communication
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15804 , vital:40528
- Description: Music, before and after independence in the former colonies, has been playing a central role of articulating national concerns. It became an alternative medium through which historical narratives were channeled out to the public. While many scholars have acknowledged the critical role of music’s attempt to whip the autocratic governments into line, and the attempts by the governments across the world to thwart the critical/activism role of music, little emphasis was put on the mechanism of circumventing censorship, the linguistic competence (or lack of it) of music in conscientising the public on national issues. This thesis aims to harness this seemingly entertainment tool (music) into serious academic discourse by looking at the way power relations and ideological contestations are symbolically reflected, represented and communicated in popular culture, in particular the Zimbabwean Sungura and Chimurenga music. It makes a critical analysis of the diction of music as it attempts (or fails to) reflect and represent the Zimbabwean historical narratives from the early 1990s to 2008. The study tries to (semiologically) fracture the musical lexicon and the ideological stance on which it is based to show the extent to which music communicates by way of reflecting and representing the Zimbabwean historical narratives. The thesis looks at how popular music has ‘become the most prominent signifier’ and at ‘the shifting meanings and the significance of … music’ (Nooshin 2005:231) in Zimbabwe. It utilises a qualitative research approach specifically an interpretive prism. Key research methods for the study include in-depth semi-structured interviews which were conducted with purposively selected informants such as university academics and two of the selected musicians. The selected academics were purposively sampled basing on the researcher’s knowledge of their inclination towards Cultural Studies, particularly popular culture. The study has managed to bring clarity to the research questions in a big way considering the application of the various theories that framed the thesis discussion. Research findings indicate that interpretive semiotics aids to unpack the philosophy of meaning making through song. Music as a medium has the reflective effect of a mirror and a photographic effect of a camera to enunciate the ideological innuendo in the leader-led dichotomy. The study shows that protest popular music rejects knowledge that affirms the status quo; it is counter hegemonic and seeks to regenerate selfhoods and self-liberation amongst the subaltern class.
- Full Text:
- Date Issued: 2019
Regional thickening as game-changing: examining transnational activities of gender and women-focused civil society actors for region-building in Southern Africa
- Authors: Nedziwe, Cecilia Lwiindi
- Date: 2019
- Subjects: International relations , Southern Africa Development Community , Regionalism -- Africa, Southern , Africa, Southern -- Foreign relations -- 1994- , Women in development -- Africa, Southern , Women -- Social conditions -- Africa, Southern , Women -- Political activity -- Africa, Southern , Women in public life -- Africa, Southern , Civil society -- Africa, Southern
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/95420 , vital:31154
- Description: This thesis argues that norms, in general, have proliferated in a neo-liberalising context since the 1990s, in particular norms on gender, and how they have changed to indicate new agency and influence, amounts to game change. Despite growing transnational activities, regionalisation and the increasing interface between state and non-state regionalism in a transnational context since the advent of liberalisation and democratisation, analyses in regional International Relations (IR) studies, so far, largely maintain linear logic. The increasing non-state processes, and their connection to state processes in norm creation, norm adaptation, norm diffusion and implementation around broad questions of security including in the area of gender, amount to regional thickening. Regional thickening revealed in terms of increasing regionalisation, regionalism, and region-ness whose effect is game-changing challenges mainstream linear approaches in regional IR studies. Game-changing here, refers to, processes promoting the development of norms mentioned above in the interest of contributing to improved security across a region. This study is focused on Southern Africa, defined here, as the Southern African Development Community (SADC) region. This study’s analytical approach is informed by alternatives to mainstream approaches, emphasising processes, rather than linearity inherent in regional IR studies. By privileging the actual game-changing processes, interactions, and agency around the norm development cycle, this study examines how regional thickening in a transnational context promotes game-changing activities, promoting the development of the norm cycle, seeking to have improved security. A mixed method approach involving gathering of information from multiple primary and secondary sources are used. The study found transnational activities and regionalisation of gender and women-focused civil society actors, game-changing. These civil society actors organised in two ways. First, by way of advocacy and in seeking representation within intergovernmental policymaking structures at a regional level. Second, by way of organising around transnational communities in a transnational context in the interest of addressing gendered insecurities at localised levels. Regional thickening as game-changing here pointed to a growing recognition and participation of civil society actors in intergovernmental policymaking spaces as having created a groundswell for game change at localised levels. This led to policy development, adaptation, diffusion, and implementation by both state and non-state actors contributing to norm changes, improved social policies, and to greater security. The actual changes emerging from these actors’ activities on the ground are in terms of unlearning patriarchal behaviours, opening up development for women, and increasing their living standards, education, health, and their freedom. In assessing the transnational environment on gendered insecurity in Southern Africa, this thesis developed an innovative framework of regional thickening as game-changing. This framework plots how game-changing developed, evolved, and its importance in addressing gendered insecurity. The thesis has proposed that game-changing transnational activities and regionalisation that change, and diffuse norms to break learnt behaviour, have helped disrupt rigid institutionalisation, and are aiding to bring non-linear discourses to the fore.
- Full Text:
- Date Issued: 2019
- Authors: Nedziwe, Cecilia Lwiindi
- Date: 2019
- Subjects: International relations , Southern Africa Development Community , Regionalism -- Africa, Southern , Africa, Southern -- Foreign relations -- 1994- , Women in development -- Africa, Southern , Women -- Social conditions -- Africa, Southern , Women -- Political activity -- Africa, Southern , Women in public life -- Africa, Southern , Civil society -- Africa, Southern
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/95420 , vital:31154
- Description: This thesis argues that norms, in general, have proliferated in a neo-liberalising context since the 1990s, in particular norms on gender, and how they have changed to indicate new agency and influence, amounts to game change. Despite growing transnational activities, regionalisation and the increasing interface between state and non-state regionalism in a transnational context since the advent of liberalisation and democratisation, analyses in regional International Relations (IR) studies, so far, largely maintain linear logic. The increasing non-state processes, and their connection to state processes in norm creation, norm adaptation, norm diffusion and implementation around broad questions of security including in the area of gender, amount to regional thickening. Regional thickening revealed in terms of increasing regionalisation, regionalism, and region-ness whose effect is game-changing challenges mainstream linear approaches in regional IR studies. Game-changing here, refers to, processes promoting the development of norms mentioned above in the interest of contributing to improved security across a region. This study is focused on Southern Africa, defined here, as the Southern African Development Community (SADC) region. This study’s analytical approach is informed by alternatives to mainstream approaches, emphasising processes, rather than linearity inherent in regional IR studies. By privileging the actual game-changing processes, interactions, and agency around the norm development cycle, this study examines how regional thickening in a transnational context promotes game-changing activities, promoting the development of the norm cycle, seeking to have improved security. A mixed method approach involving gathering of information from multiple primary and secondary sources are used. The study found transnational activities and regionalisation of gender and women-focused civil society actors, game-changing. These civil society actors organised in two ways. First, by way of advocacy and in seeking representation within intergovernmental policymaking structures at a regional level. Second, by way of organising around transnational communities in a transnational context in the interest of addressing gendered insecurities at localised levels. Regional thickening as game-changing here pointed to a growing recognition and participation of civil society actors in intergovernmental policymaking spaces as having created a groundswell for game change at localised levels. This led to policy development, adaptation, diffusion, and implementation by both state and non-state actors contributing to norm changes, improved social policies, and to greater security. The actual changes emerging from these actors’ activities on the ground are in terms of unlearning patriarchal behaviours, opening up development for women, and increasing their living standards, education, health, and their freedom. In assessing the transnational environment on gendered insecurity in Southern Africa, this thesis developed an innovative framework of regional thickening as game-changing. This framework plots how game-changing developed, evolved, and its importance in addressing gendered insecurity. The thesis has proposed that game-changing transnational activities and regionalisation that change, and diffuse norms to break learnt behaviour, have helped disrupt rigid institutionalisation, and are aiding to bring non-linear discourses to the fore.
- Full Text:
- Date Issued: 2019
Reimagining sexuality education: Xhosa secondary school teachers from township schools talk about Xhosa culture and sexuality education
- Msutwana, Nomawonga Veronica
- Authors: Msutwana, Nomawonga Veronica
- Date: 2019
- Subjects: Education,Secondary --South africa Xhosa Culture Xhosa(african people)--Social life and customs
- Language: English
- Type: PhD
- Identifier: http://hdl.handle.net/10948/38794 , vital:34966
- Description: The study sought to explore how a deeper understanding of the influence of Xhosa cultural perspectives on learning about sexuality could inform how Xhosa Life Orientation (L0), Life Sciences (LFSC) and Natural Sciences (NS) secondary school teachers could teach sexuality education to Xhosa adolescents. Teachers who teach sexuality education do not seem to succeed in equipping their adolescent learners with the necessary knowledge, values and skills for navigating safely through the development and expression of their sexuality. This is deemed important in South Africa where the HIV and AIDS epidemic is not yet fully under control and where gender-based violence remains a problem. The study took on a qualitative, participatory visual methodology within the interpretive and critical paradigms. It drew on Cultural Historical Activity Theory (CHAT) as a lens to frame the study and through which data was interpreted and analysed. Thus, the research study involved nine female Xhosa LO, LFSC and NS township secondary school teachers who were purposively selected. Data were generated through four methods, namely document analysis, drawing, photo voice and curriculum posters. The generated data were analysed using thematic analysis and yielded rich findings for the five sub-questions, thereby answering the main research question.
- Full Text:
- Date Issued: 2019
- Authors: Msutwana, Nomawonga Veronica
- Date: 2019
- Subjects: Education,Secondary --South africa Xhosa Culture Xhosa(african people)--Social life and customs
- Language: English
- Type: PhD
- Identifier: http://hdl.handle.net/10948/38794 , vital:34966
- Description: The study sought to explore how a deeper understanding of the influence of Xhosa cultural perspectives on learning about sexuality could inform how Xhosa Life Orientation (L0), Life Sciences (LFSC) and Natural Sciences (NS) secondary school teachers could teach sexuality education to Xhosa adolescents. Teachers who teach sexuality education do not seem to succeed in equipping their adolescent learners with the necessary knowledge, values and skills for navigating safely through the development and expression of their sexuality. This is deemed important in South Africa where the HIV and AIDS epidemic is not yet fully under control and where gender-based violence remains a problem. The study took on a qualitative, participatory visual methodology within the interpretive and critical paradigms. It drew on Cultural Historical Activity Theory (CHAT) as a lens to frame the study and through which data was interpreted and analysed. Thus, the research study involved nine female Xhosa LO, LFSC and NS township secondary school teachers who were purposively selected. Data were generated through four methods, namely document analysis, drawing, photo voice and curriculum posters. The generated data were analysed using thematic analysis and yielded rich findings for the five sub-questions, thereby answering the main research question.
- Full Text:
- Date Issued: 2019
Residents’ perspectives on township tourism in Mondesa, Swakopmund, Namibia
- Auala, Lovisa Sisco Ndapanda
- Authors: Auala, Lovisa Sisco Ndapanda
- Date: 2019
- Subjects: Tourism — Namibia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/42448 , vital:36661
- Description: Township tourism is regarded as one of the fastest growing tourist activities in Namibia (Buning, Legant, Schauwinhold, Steinbrink & Subenguth, 2016:14). This research study presents an exploratory inquiry that seeks an in-depth understanding of residents’perspectives on township tourism in Mondesa, Swakopmund, Namibia.In order to conceptualise the extent to which the residents’needs are being met through the benefits derived from township tourism. The residents’ perspectives on township tourism in Mondesa areexplored with respect to the benefits and costs derived from township tourism, participation in township tourism, and interaction with tourist during a township tour and consultation on township tourismwhich forms part of the research questions ofthe study. By applying the Social Exchange Theory (SET) in this study, the relationships between the variables that influence the residents perceived benefit and costs of township tourism in Mondesa are explored further in depth in combination with Pretty’s Typology of participation and Scheyne’s typology of community empowerment in tourism (Ap, 1992: 668; Mason, 2003:119; Sharpley and Telfer, 2002:152;Cooper, Fletcher, Gilbert & Wanhill, 1993:91).These variables are namely; social, economic, psychological, environmental, cultural, Manipulative, passive, educational and political factors. They form part of the conceptual framework of the study.This study followed a qualitative research approachandmultiple data sources were collected including semi-structured interviews with residents from Mondesa:these included residents involved in township tourism and those not involved in township tourism. To triangulate the data collection, semi-structured interviews were conducted with representatives from tourism industry and government bodies related to townshiptourism. Data analysis was done through the facilitation of Atlas tiaqualitative data analysis software and deductive codes were established from the literature(variables from the conceptual framework)and themes were developed from the research questions.The findings indicate that residents who are not involved in township tourism arenot influenced by the benefit and cost equation of the social exchange theory (Andriotis, 2005:69). Therefore residents not involved in township tourism are positive about tourism irrespective of whether they benefit directly from financial gain through tourism. The findingsfurtheremphasis oncommunity benefitsfrom township tourism being as important, than individual benefits. This study also provides knowledge that meaningful interaction between tourist and residents has the ability to reduce the apartheid paradigm of racial division and discrimination, which was the basis of the formation of townships.Residents’ misconception about white people are changed due to their personal interaction and cultural exchange with white tourist during a township tour. Anothersignificant findings to emerge from this study is the ability for township tourism to transform the lives of residents living in townships through the intrinsic benefits derived from township tourism. Township tourism has the ability to contribute to positive human exchange through interaction between residents and tourists. By sharing a positive cultural exchange, strong relationships are built between the tourists and residents, which may provide long term sustainability of township tourism. The positive personal transformational effect on residents through interaction with tourists is contributing to residents’ socio-economic well-being. Therefore township tourism has the ability to quantitatively and qualitatively address the alleviationof poverty in townshipsand fostering understanding and mutual respect among peoples of the world.The studyconcluded with a framework of guidelines toaid key stakeholders in the development and planning of township tourism and encourages the practice of sustainable tourism in townships.
- Full Text:
- Date Issued: 2019
- Authors: Auala, Lovisa Sisco Ndapanda
- Date: 2019
- Subjects: Tourism — Namibia
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/42448 , vital:36661
- Description: Township tourism is regarded as one of the fastest growing tourist activities in Namibia (Buning, Legant, Schauwinhold, Steinbrink & Subenguth, 2016:14). This research study presents an exploratory inquiry that seeks an in-depth understanding of residents’perspectives on township tourism in Mondesa, Swakopmund, Namibia.In order to conceptualise the extent to which the residents’needs are being met through the benefits derived from township tourism. The residents’ perspectives on township tourism in Mondesa areexplored with respect to the benefits and costs derived from township tourism, participation in township tourism, and interaction with tourist during a township tour and consultation on township tourismwhich forms part of the research questions ofthe study. By applying the Social Exchange Theory (SET) in this study, the relationships between the variables that influence the residents perceived benefit and costs of township tourism in Mondesa are explored further in depth in combination with Pretty’s Typology of participation and Scheyne’s typology of community empowerment in tourism (Ap, 1992: 668; Mason, 2003:119; Sharpley and Telfer, 2002:152;Cooper, Fletcher, Gilbert & Wanhill, 1993:91).These variables are namely; social, economic, psychological, environmental, cultural, Manipulative, passive, educational and political factors. They form part of the conceptual framework of the study.This study followed a qualitative research approachandmultiple data sources were collected including semi-structured interviews with residents from Mondesa:these included residents involved in township tourism and those not involved in township tourism. To triangulate the data collection, semi-structured interviews were conducted with representatives from tourism industry and government bodies related to townshiptourism. Data analysis was done through the facilitation of Atlas tiaqualitative data analysis software and deductive codes were established from the literature(variables from the conceptual framework)and themes were developed from the research questions.The findings indicate that residents who are not involved in township tourism arenot influenced by the benefit and cost equation of the social exchange theory (Andriotis, 2005:69). Therefore residents not involved in township tourism are positive about tourism irrespective of whether they benefit directly from financial gain through tourism. The findingsfurtheremphasis oncommunity benefitsfrom township tourism being as important, than individual benefits. This study also provides knowledge that meaningful interaction between tourist and residents has the ability to reduce the apartheid paradigm of racial division and discrimination, which was the basis of the formation of townships.Residents’ misconception about white people are changed due to their personal interaction and cultural exchange with white tourist during a township tour. Anothersignificant findings to emerge from this study is the ability for township tourism to transform the lives of residents living in townships through the intrinsic benefits derived from township tourism. Township tourism has the ability to contribute to positive human exchange through interaction between residents and tourists. By sharing a positive cultural exchange, strong relationships are built between the tourists and residents, which may provide long term sustainability of township tourism. The positive personal transformational effect on residents through interaction with tourists is contributing to residents’ socio-economic well-being. Therefore township tourism has the ability to quantitatively and qualitatively address the alleviationof poverty in townshipsand fostering understanding and mutual respect among peoples of the world.The studyconcluded with a framework of guidelines toaid key stakeholders in the development and planning of township tourism and encourages the practice of sustainable tourism in townships.
- Full Text:
- Date Issued: 2019
Responding to iconic images of risk through reflexive and narrative enquiry represented in a stratified text for environmental education readers
- Authors: Murphy, Mary
- Date: 2019
- Subjects: Sustainability -- Study and teaching , Environmental education -- Philosophy , Environmental degradation -- Study and teaching , Environmental degradation -- Philosophy , Reflection (Philosophy) , Archer, Margaret S (Margaret Scotford). Structure, agency, and the internal conversation
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/96768 , vital:31318
- Description: This thesis presents a stratified textual strategy to represent meaning developed through reflexive and narrative enquiry of environmental risk. Meaning that emerged in responses to iconic images of risk. Umberto Eco cautioned that iconic images over time become conventional taking over from that which they represent. Representations of risk become embedded through cultural coding. Semiotic theory provided access to the contextual and cultural content of environmental education as experienced during professional work as a radio presenter of “Environmental Matters”, as an environmental educator and activist. Methodological rigour was applied through the application of Margaret Archer's theory of the internal conversation and use of an online content management system. Both the reflexive tool of the internal conversation and the textual mechanism of the blog encouraged commitment to Paul Hart's criteria of trustworthiness and authenticity in the process of building the semiotic structure of the PhD. The Internal Conversation was used as a mediating tool in the PhD process and is presented in practice. Rethinking environmental risk from other species' perspectives through imagined experience was achieved through narrative enquiry. A noted anthropocentric limitation of the inability to interview animals for their experience of human-imposed risk was mitigated through representing the imagined, possible perspectives through story, which invites the reader to join the meaning-making process and open up discussions for and about environmental issues and action. This noted anthropocentrism was evident in debates among the characters about violence and non-violence as a conditioned theme and topic discussed in previous academic research about terrorism in divided societies. The story illustrates how the main character, a penguin called Polo, navigates through emerging meaning within a structure that confronts him with choices that end with a decision to become an agent for change. This story is a narrative example of the morphogenetic process. The multi-textual strategy presents possible methods for the exploration of risk (Vol. 1), reflexivity (Vol. 2) and representation (Vol. 3) for the application and contribution in/to environmental education.
- Full Text:
- Date Issued: 2019
- Authors: Murphy, Mary
- Date: 2019
- Subjects: Sustainability -- Study and teaching , Environmental education -- Philosophy , Environmental degradation -- Study and teaching , Environmental degradation -- Philosophy , Reflection (Philosophy) , Archer, Margaret S (Margaret Scotford). Structure, agency, and the internal conversation
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/96768 , vital:31318
- Description: This thesis presents a stratified textual strategy to represent meaning developed through reflexive and narrative enquiry of environmental risk. Meaning that emerged in responses to iconic images of risk. Umberto Eco cautioned that iconic images over time become conventional taking over from that which they represent. Representations of risk become embedded through cultural coding. Semiotic theory provided access to the contextual and cultural content of environmental education as experienced during professional work as a radio presenter of “Environmental Matters”, as an environmental educator and activist. Methodological rigour was applied through the application of Margaret Archer's theory of the internal conversation and use of an online content management system. Both the reflexive tool of the internal conversation and the textual mechanism of the blog encouraged commitment to Paul Hart's criteria of trustworthiness and authenticity in the process of building the semiotic structure of the PhD. The Internal Conversation was used as a mediating tool in the PhD process and is presented in practice. Rethinking environmental risk from other species' perspectives through imagined experience was achieved through narrative enquiry. A noted anthropocentric limitation of the inability to interview animals for their experience of human-imposed risk was mitigated through representing the imagined, possible perspectives through story, which invites the reader to join the meaning-making process and open up discussions for and about environmental issues and action. This noted anthropocentrism was evident in debates among the characters about violence and non-violence as a conditioned theme and topic discussed in previous academic research about terrorism in divided societies. The story illustrates how the main character, a penguin called Polo, navigates through emerging meaning within a structure that confronts him with choices that end with a decision to become an agent for change. This story is a narrative example of the morphogenetic process. The multi-textual strategy presents possible methods for the exploration of risk (Vol. 1), reflexivity (Vol. 2) and representation (Vol. 3) for the application and contribution in/to environmental education.
- Full Text:
- Date Issued: 2019
Rural food security in Mutare District, Zimbabwe, 1947-2010
- Authors: Kusena, Bernard
- Date: 2019
- Subjects: Mutare (Zimbabwe) -- History , Zimbabwe -- History , Food security -- Zimbabwe , Poverty -- Zimbabwe , Rural pooer -- Zimbabwe , Crop losses -- Zimbabwe , Food relief -- Zimbabwe
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92865 , vital:30757
- Description: By taking Mutare District as its lens to explore the dynamics of rural food security in Zimbabwe, this thesis assesses the role of the state in tackling hunger among its rural populations. It examines the impact of colonial and post-colonial food policy on efforts to combat food insecurity. The thesis explores the uneasy options pursued by rural communities in response to droughts and other threats of hunger. It identifies and ranks crop failure as the chief culprit to the district’s efforts towards food security. The thesis illustrates the contestations between the state and its rural people over which sustainable approaches to adopt in order to end hunger and how such debates continually shaped policy. It grapples with questions about the various understandings of food security advanced by scholars within the rural African context. It demonstrates, for instance, that the post-colonial state inherited an erstwhile crop production structure which shunned food crops in favour of cash crops. There was obvious bias against local preferences for a robust, home-grown food regime which did not put rural livelihoods at risk of starvation. The thesis also argues that food can be used as an instrument of war as evidenced during the liberation struggle when the vast majority of people residing in rural areas, particularly women and children, were pushed to the edges of survival. In addition, the thesis demonstrates that the infamous Marange diamonds turned out to be a curse rather than a blessing due to the state’s lack of transparency in the beneficiation chain. It concludes by a detailed examination of the political economy of food aid, demonstrating why donors have not succeeded for long to combat hunger in the district. In light of this background, the thesis provides a more nuanced analysis of the whole question of rural food security using archival material, newspapers, government and civil society reports, interviews and field observation. The thesis benefits from the use of a multi-pronged theoretical framework to capture the disparate themes that form the bedrock of this study.
- Full Text:
- Date Issued: 2019
- Authors: Kusena, Bernard
- Date: 2019
- Subjects: Mutare (Zimbabwe) -- History , Zimbabwe -- History , Food security -- Zimbabwe , Poverty -- Zimbabwe , Rural pooer -- Zimbabwe , Crop losses -- Zimbabwe , Food relief -- Zimbabwe
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92865 , vital:30757
- Description: By taking Mutare District as its lens to explore the dynamics of rural food security in Zimbabwe, this thesis assesses the role of the state in tackling hunger among its rural populations. It examines the impact of colonial and post-colonial food policy on efforts to combat food insecurity. The thesis explores the uneasy options pursued by rural communities in response to droughts and other threats of hunger. It identifies and ranks crop failure as the chief culprit to the district’s efforts towards food security. The thesis illustrates the contestations between the state and its rural people over which sustainable approaches to adopt in order to end hunger and how such debates continually shaped policy. It grapples with questions about the various understandings of food security advanced by scholars within the rural African context. It demonstrates, for instance, that the post-colonial state inherited an erstwhile crop production structure which shunned food crops in favour of cash crops. There was obvious bias against local preferences for a robust, home-grown food regime which did not put rural livelihoods at risk of starvation. The thesis also argues that food can be used as an instrument of war as evidenced during the liberation struggle when the vast majority of people residing in rural areas, particularly women and children, were pushed to the edges of survival. In addition, the thesis demonstrates that the infamous Marange diamonds turned out to be a curse rather than a blessing due to the state’s lack of transparency in the beneficiation chain. It concludes by a detailed examination of the political economy of food aid, demonstrating why donors have not succeeded for long to combat hunger in the district. In light of this background, the thesis provides a more nuanced analysis of the whole question of rural food security using archival material, newspapers, government and civil society reports, interviews and field observation. The thesis benefits from the use of a multi-pronged theoretical framework to capture the disparate themes that form the bedrock of this study.
- Full Text:
- Date Issued: 2019
Shifting contexts, shifting identities: a realist exploration of transnational mobility, change and identity construction in South African Higher Education expatriates in Abu Dhabi, UAE.
- Authors: Reid, Gillian Janet
- Date: 2019
- Subjects: College teacher mobility , College teacher mobility -- Abū Ẓaby (United Arab Emirates) , College teachers, Foreign -- Abū Ẓaby (United Arab Emirates) , College teachers -- Psychology , Expatriation -- Psychological aspects
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92898 , vital:30760
- Description: Positioned in relation to the globalization of higher education, this realist study is approached from an interest in identity and focuses on nine South African academics professional contexts in South Africa and Abu Dhabi, UAE. As the context of identity formation and emergence is always local, the intention of this research was never to generalize. Rather, in using Bhaskar’s critical realism as its underpinning philosophy, and Archer’s social realism, theories on self, personal and the development and attainment of social identity - her concept of analytical dualism and her morphogenetic framework, this qualitative case study was designed to explore how global and national powers and mechanism effected change in this sub-group of academic’s respective higher education sectors and institutions in post- 1994 South Africa and in Abu Dhabi between 2008 and 2016. The study suggests that participants perceived their academic roles and role-incumbent professional identities to have been negatively impacted by the changes that were implemented in the South African higher education sector as a result the countries reintroduction to the global stage. Their response to become transnational educators in Abu Dhabi’s presented them with conditions that allied their professional experiences of the transformation of South African’s higher education sector. This led to a continued sense of loss of academic agency and powerlessness. This effecting the emergence, through the personal power of reflectivity, combined with discourse and affinity powers and mechanisms, in a social identity that supplanted their academic identities.
- Full Text:
- Date Issued: 2019
- Authors: Reid, Gillian Janet
- Date: 2019
- Subjects: College teacher mobility , College teacher mobility -- Abū Ẓaby (United Arab Emirates) , College teachers, Foreign -- Abū Ẓaby (United Arab Emirates) , College teachers -- Psychology , Expatriation -- Psychological aspects
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92898 , vital:30760
- Description: Positioned in relation to the globalization of higher education, this realist study is approached from an interest in identity and focuses on nine South African academics professional contexts in South Africa and Abu Dhabi, UAE. As the context of identity formation and emergence is always local, the intention of this research was never to generalize. Rather, in using Bhaskar’s critical realism as its underpinning philosophy, and Archer’s social realism, theories on self, personal and the development and attainment of social identity - her concept of analytical dualism and her morphogenetic framework, this qualitative case study was designed to explore how global and national powers and mechanism effected change in this sub-group of academic’s respective higher education sectors and institutions in post- 1994 South Africa and in Abu Dhabi between 2008 and 2016. The study suggests that participants perceived their academic roles and role-incumbent professional identities to have been negatively impacted by the changes that were implemented in the South African higher education sector as a result the countries reintroduction to the global stage. Their response to become transnational educators in Abu Dhabi’s presented them with conditions that allied their professional experiences of the transformation of South African’s higher education sector. This led to a continued sense of loss of academic agency and powerlessness. This effecting the emergence, through the personal power of reflectivity, combined with discourse and affinity powers and mechanisms, in a social identity that supplanted their academic identities.
- Full Text:
- Date Issued: 2019
Simulation as a teaching methodology in midwifery education
- Authors: Rall, Nadine
- Date: 2019
- Subjects: Midwifery -- Study and teaching
- Language: English
- Type: Thesis , Doctorate , PhD
- Identifier: http://hdl.handle.net/10948/43013 , vital:36724
- Description: Increased rates of maternal and perinatal deaths remain a challenge in many countries. According to the National Committee on Confidential Enquiries into Maternal Deaths report maternal deaths in South Africa are also related to avoidable factors that could be among other reasons, because of poor performance by midwives. Since such poor performance is further associated with the different forms of clinical practice being taught by nurse educators in midwifery education at different nursing Education Institutions. Thus a revised common clinical teaching methodology, in the form of strategies, utilized in all the training nursing education institutions of final-year undergraduate midwifery students is needed. It would have an impact on how well midwifery students are uniformly prepared for role-taking in clinical practice. The overarching aim of the study was to develop strategies to facilitate simulation as a teaching methodology in midwifery education. The objectives for this study were to:•explore and describe the perceptions of midwifery students with regard to their preparation for role-taking in clinical practice;•explore and describe the perceptions of nurse educators with regard to simulation as a teaching methodology in midwifery education;•provide a literature context with regard to simulation as a teaching methodology in midwifery education, and•develop strategies to facilitate simulation as a teaching methodology for midwifery education. The study followed a qualitative, exploratory, descriptive and contextual research approach design, applying Kolb’s theory (1984) of experiential learning as the paradigm in four phases. In Phase one, the researcher collected data from two groups of participants using semi-structured one-on-one and focus group voice recorded interviews. Focus group interviews were arranged with 27final-year undergraduate midwifery students(Group 1) and individual interviews were conducted with 12 nurse educators (Group 2) in midwifery education and were inclusive of those in the pilot study. viThe participants were purposefully selected across three provinces of South Africa in four nursing Education Institutionsusing set inclusion criteria. Data analysis was done using Saldaña’s (2009) method of content analysis. The researcher and an independent coder analysed and coded the data independently from each other and concurrently for both groups of participants. From the results, three main themes and eight sub-themes emerged. Theme One combined the experiences of both groups and highlighted their experience of simulation as being beneficial. Theme Two addressed the barriers encountered by the participants of both groups when the simulation was used as a teaching methodology. Theme Three addressed the various recommendations that were suggested by both groups of participants on how to strengthen simulation as a teaching methodology. In Phase Two, a contextual description was provided about simulation as a teaching methodology in midwifery education through the use of related literature. The contextual description included the macro-, meso-and micro-environments as related to the use of simulation as a teaching methodology in midwifery education. In Phase Three, following contextual description of the concept of simulation as a teaching methodology the main concept of the study had to be identified and served as a foundation for strategies. The research themes became foundational content for the conceptual framework which was developed using the principles of Dickoff, James and Wiedenbach (1968) as a guide towards the needed strategies for the study. Lastly, in Phase Four three strategies were developed for the facilitation of simulation as a teaching methodology in midwifery education. The three main strategies developed were as follows:•mobilise resources, to facilitate the implementation of simulation in midwifery education;•create an environment conducive to supporting simulation education; and •design a relevant midwifery programme that accommodates simulation within the clinical module. The developed strategies will assist nurse educators to be better prepared to implement midwifery simulation as a teaching methodology in midwifery education. The three principles of research ethics according to The Belmont Report namely, respect for human dignity, beneficence and justice were adhered to throughout the study. Trustworthiness was ensured according to the four principles indicated by Lincoln and Guba’s (1985) Model of Trustworthiness which included credibility, dependability, transferability and neutrality.
- Full Text:
- Date Issued: 2019
- Authors: Rall, Nadine
- Date: 2019
- Subjects: Midwifery -- Study and teaching
- Language: English
- Type: Thesis , Doctorate , PhD
- Identifier: http://hdl.handle.net/10948/43013 , vital:36724
- Description: Increased rates of maternal and perinatal deaths remain a challenge in many countries. According to the National Committee on Confidential Enquiries into Maternal Deaths report maternal deaths in South Africa are also related to avoidable factors that could be among other reasons, because of poor performance by midwives. Since such poor performance is further associated with the different forms of clinical practice being taught by nurse educators in midwifery education at different nursing Education Institutions. Thus a revised common clinical teaching methodology, in the form of strategies, utilized in all the training nursing education institutions of final-year undergraduate midwifery students is needed. It would have an impact on how well midwifery students are uniformly prepared for role-taking in clinical practice. The overarching aim of the study was to develop strategies to facilitate simulation as a teaching methodology in midwifery education. The objectives for this study were to:•explore and describe the perceptions of midwifery students with regard to their preparation for role-taking in clinical practice;•explore and describe the perceptions of nurse educators with regard to simulation as a teaching methodology in midwifery education;•provide a literature context with regard to simulation as a teaching methodology in midwifery education, and•develop strategies to facilitate simulation as a teaching methodology for midwifery education. The study followed a qualitative, exploratory, descriptive and contextual research approach design, applying Kolb’s theory (1984) of experiential learning as the paradigm in four phases. In Phase one, the researcher collected data from two groups of participants using semi-structured one-on-one and focus group voice recorded interviews. Focus group interviews were arranged with 27final-year undergraduate midwifery students(Group 1) and individual interviews were conducted with 12 nurse educators (Group 2) in midwifery education and were inclusive of those in the pilot study. viThe participants were purposefully selected across three provinces of South Africa in four nursing Education Institutionsusing set inclusion criteria. Data analysis was done using Saldaña’s (2009) method of content analysis. The researcher and an independent coder analysed and coded the data independently from each other and concurrently for both groups of participants. From the results, three main themes and eight sub-themes emerged. Theme One combined the experiences of both groups and highlighted their experience of simulation as being beneficial. Theme Two addressed the barriers encountered by the participants of both groups when the simulation was used as a teaching methodology. Theme Three addressed the various recommendations that were suggested by both groups of participants on how to strengthen simulation as a teaching methodology. In Phase Two, a contextual description was provided about simulation as a teaching methodology in midwifery education through the use of related literature. The contextual description included the macro-, meso-and micro-environments as related to the use of simulation as a teaching methodology in midwifery education. In Phase Three, following contextual description of the concept of simulation as a teaching methodology the main concept of the study had to be identified and served as a foundation for strategies. The research themes became foundational content for the conceptual framework which was developed using the principles of Dickoff, James and Wiedenbach (1968) as a guide towards the needed strategies for the study. Lastly, in Phase Four three strategies were developed for the facilitation of simulation as a teaching methodology in midwifery education. The three main strategies developed were as follows:•mobilise resources, to facilitate the implementation of simulation in midwifery education;•create an environment conducive to supporting simulation education; and •design a relevant midwifery programme that accommodates simulation within the clinical module. The developed strategies will assist nurse educators to be better prepared to implement midwifery simulation as a teaching methodology in midwifery education. The three principles of research ethics according to The Belmont Report namely, respect for human dignity, beneficence and justice were adhered to throughout the study. Trustworthiness was ensured according to the four principles indicated by Lincoln and Guba’s (1985) Model of Trustworthiness which included credibility, dependability, transferability and neutrality.
- Full Text:
- Date Issued: 2019
Social Media as Human Rights Watchdog: A critical Analysis of Facebook and WhatsApp use by Citizens and Civil Society Groups in the Run-up to the 2018 Elections in Zimbabwe
- Authors: Mututwa, Wishes.T
- Date: 2019
- Subjects: Social media Online social networks
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15837 , vital:40531
- Description: This study analysed the use of social media platforms, WhatsApp and Facebook in monitoring human rights ahead of Zimbabwe’s 2018 Harmonised elections. Zimbabwe has witnessed gross human rights violations since the attainment of independence in 1980 but most of these violations have been misrepresented, partially captured or ignored particularly by the partisan state media. While issues of human rights have been researched on, there has been a gap in research on the role of social media in safeguarding human rights in Zimbabwe, particularly during election times. There has also been a gap in research about the influences of social media, not just to inspire revolutions but to strengthen democratic practices in Zimbabwe through vibrant discussions of human rights issues on social media platforms. This study was informed by Habermas Theory of public sphere and Social network theory in order to analyse texts shared and discussed on WhatsApp and Facebook about human rights committed ahead of 2018 Harmonised elections. The aim was to establish use of social media as watchdog of human rights. A qualitative content analysis was applied to study texts shared on WhatsApp and Facebook about human rights violations across the country. Three WhatsApp groups and seven Facebook pages were selected for the study from which posts and responses from participants were extracted for analysis. The findings of the study revealed that social media can effectively strengthen democratic practices by exposing government’s unconstitutional practices. Further, social media can be useful in offering ordinary citizens a platform for engagement with civic society as they discuss issues that affect them. The findings of the study also hold the state accountable for the majority of human rights abuses committed throughout the election campaign period. The study then recommended that the government of Zimbabwe should go back to constitutionalism and abide by international human rights treaties to which they are signatory. Further, the study recommended that Zimbabwe Human Rights Commission and other independent commissions be empowered so that human rights are fully enjoyed in Zimbabwe, not just during election campaign periods but all the time
- Full Text:
- Date Issued: 2019
- Authors: Mututwa, Wishes.T
- Date: 2019
- Subjects: Social media Online social networks
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15837 , vital:40531
- Description: This study analysed the use of social media platforms, WhatsApp and Facebook in monitoring human rights ahead of Zimbabwe’s 2018 Harmonised elections. Zimbabwe has witnessed gross human rights violations since the attainment of independence in 1980 but most of these violations have been misrepresented, partially captured or ignored particularly by the partisan state media. While issues of human rights have been researched on, there has been a gap in research on the role of social media in safeguarding human rights in Zimbabwe, particularly during election times. There has also been a gap in research about the influences of social media, not just to inspire revolutions but to strengthen democratic practices in Zimbabwe through vibrant discussions of human rights issues on social media platforms. This study was informed by Habermas Theory of public sphere and Social network theory in order to analyse texts shared and discussed on WhatsApp and Facebook about human rights committed ahead of 2018 Harmonised elections. The aim was to establish use of social media as watchdog of human rights. A qualitative content analysis was applied to study texts shared on WhatsApp and Facebook about human rights violations across the country. Three WhatsApp groups and seven Facebook pages were selected for the study from which posts and responses from participants were extracted for analysis. The findings of the study revealed that social media can effectively strengthen democratic practices by exposing government’s unconstitutional practices. Further, social media can be useful in offering ordinary citizens a platform for engagement with civic society as they discuss issues that affect them. The findings of the study also hold the state accountable for the majority of human rights abuses committed throughout the election campaign period. The study then recommended that the government of Zimbabwe should go back to constitutionalism and abide by international human rights treaties to which they are signatory. Further, the study recommended that Zimbabwe Human Rights Commission and other independent commissions be empowered so that human rights are fully enjoyed in Zimbabwe, not just during election campaign periods but all the time
- Full Text:
- Date Issued: 2019
Socio-ecological, contextual effects in Raven’s Colour Progressive Matrices scores: developing an index for guiding test selection and interpretation
- Authors: August, Justin Oswin
- Date: 2019
- Subjects: Psychological testing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/50214 , vital:42071
- Description: With the changing landscape in South Africa to full democracy, increased research has been undertaken in the psychometric field on local and national normative studies regarding various assessment measures. Given that the Raven’s Coloured Progressive Matrices (CPM) is purported to be culture-free and not heavily dependent on verbal and language skills; it has been extensively normed throughout the world for various population groups. While norms for normal populations of children have been developed in South Africa, these studies were based on race and gender predominantly and without taking into consideration the effects of socio-ecological factors on test performance. The research study aimed to understand the influence of socio-ecological factors on the expression of cognitive scores amongst a geographically diverse sample of South African learners. Through this study, research on the interplay between context and cognition was to be located within the Ecological Systems model of Bronfenbrenner. A secondary aim of the study was to develop an index that will guide test selection and interpretation of assessment results, taking into account the influence of socio-ecological factors and providing a conceptual framework for future test development. The study employed a quantitative methodology on a South African sample consisting of primary school children aged between the ages of 6 years to 11 years. The sample was drawn from schools in the Port Elizabeth area in South Africa that were classified into low, medium, and high opportunity, based on context. The results indicated that the type of school had a significant impact on test performance, suggesting that contextual factors were influential in this process. The item analysis conducted further indicated that learners from a low opportunity school performed significantly lower than the other two schools in the sample. The index development provides a foundation for further research that would enhance the interpretation of test results. In the South African context, this is considered important, given our political history and our diversity where a “one size fits all” approach is not possible.
- Full Text:
- Date Issued: 2019
- Authors: August, Justin Oswin
- Date: 2019
- Subjects: Psychological testing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/50214 , vital:42071
- Description: With the changing landscape in South Africa to full democracy, increased research has been undertaken in the psychometric field on local and national normative studies regarding various assessment measures. Given that the Raven’s Coloured Progressive Matrices (CPM) is purported to be culture-free and not heavily dependent on verbal and language skills; it has been extensively normed throughout the world for various population groups. While norms for normal populations of children have been developed in South Africa, these studies were based on race and gender predominantly and without taking into consideration the effects of socio-ecological factors on test performance. The research study aimed to understand the influence of socio-ecological factors on the expression of cognitive scores amongst a geographically diverse sample of South African learners. Through this study, research on the interplay between context and cognition was to be located within the Ecological Systems model of Bronfenbrenner. A secondary aim of the study was to develop an index that will guide test selection and interpretation of assessment results, taking into account the influence of socio-ecological factors and providing a conceptual framework for future test development. The study employed a quantitative methodology on a South African sample consisting of primary school children aged between the ages of 6 years to 11 years. The sample was drawn from schools in the Port Elizabeth area in South Africa that were classified into low, medium, and high opportunity, based on context. The results indicated that the type of school had a significant impact on test performance, suggesting that contextual factors were influential in this process. The item analysis conducted further indicated that learners from a low opportunity school performed significantly lower than the other two schools in the sample. The index development provides a foundation for further research that would enhance the interpretation of test results. In the South African context, this is considered important, given our political history and our diversity where a “one size fits all” approach is not possible.
- Full Text:
- Date Issued: 2019
South Africa-based diaspora movements and the pursuit of democratic consolidation in Zimbabwe
- Authors: Ndlovu, Sitembiso Irene
- Date: 2019
- Subjects: African diaspora
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15848 , vital:40532
- Description: The study investigates South Africa-based Diaspora movements and their pursuit of democratic consolidation in Zimbabwe. The study is a qualitative one and made use of both primary and secondary sources. Primary sources included in-depth interviews, Facebook and Twitter posts, whilst secondary sources included textbooks and online journals. The study is premised on both the Political Process and Critical Theories. The study acknowledges that CSOs in general are important key players and have been identified as one of the major actors capable of helping in consolidating democracy. Zimbabwean Diaspora movements have been on the rise due to the mass exodus of its citizens to South Africa following economic collapse and civil strife in the country. The study found out that the civil society and political space in Zimbabwe is mired by partisan use of state security forces, repressive legislations, abuse of human rights and politicisation of the judicial system. These notwithstanding, the study reveals ZEF, CiZC and ZRYM have played their part in trying to consolidate democracy in Zimbabwe from their base in South Africa. They have employed various strategies and these include submitting petitions, advocacy and lobbying, partnerships and dialogues and making use of the Social media. Some of the breakthroughs recorded include educating Zimbabweans and disseminating information through social media, raising awareness and contributing to policy formation. The study, however, notes that apart from their achievements, they have also faced challenges like inadequate resources, xenophobia, leadership crises and donor fatigue. Key findings inferred that strategies used did not yield desired outcomes, and challenges faced made consolidating democracy in Zimbabwe a daunting task. The study recommends that partnerships between the Zimbabwean government and Diaspora movements need to be introduced and sustained in a way that catalyses a relationship where discussions can take place for democracy to be consolidated in Zimbabwe without any form of hostility from the government
- Full Text:
- Date Issued: 2019
- Authors: Ndlovu, Sitembiso Irene
- Date: 2019
- Subjects: African diaspora
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15848 , vital:40532
- Description: The study investigates South Africa-based Diaspora movements and their pursuit of democratic consolidation in Zimbabwe. The study is a qualitative one and made use of both primary and secondary sources. Primary sources included in-depth interviews, Facebook and Twitter posts, whilst secondary sources included textbooks and online journals. The study is premised on both the Political Process and Critical Theories. The study acknowledges that CSOs in general are important key players and have been identified as one of the major actors capable of helping in consolidating democracy. Zimbabwean Diaspora movements have been on the rise due to the mass exodus of its citizens to South Africa following economic collapse and civil strife in the country. The study found out that the civil society and political space in Zimbabwe is mired by partisan use of state security forces, repressive legislations, abuse of human rights and politicisation of the judicial system. These notwithstanding, the study reveals ZEF, CiZC and ZRYM have played their part in trying to consolidate democracy in Zimbabwe from their base in South Africa. They have employed various strategies and these include submitting petitions, advocacy and lobbying, partnerships and dialogues and making use of the Social media. Some of the breakthroughs recorded include educating Zimbabweans and disseminating information through social media, raising awareness and contributing to policy formation. The study, however, notes that apart from their achievements, they have also faced challenges like inadequate resources, xenophobia, leadership crises and donor fatigue. Key findings inferred that strategies used did not yield desired outcomes, and challenges faced made consolidating democracy in Zimbabwe a daunting task. The study recommends that partnerships between the Zimbabwean government and Diaspora movements need to be introduced and sustained in a way that catalyses a relationship where discussions can take place for democracy to be consolidated in Zimbabwe without any form of hostility from the government
- Full Text:
- Date Issued: 2019
Stakeholder relationship management of a Chinese Mining Organisation in Zimbabwe
- Authors: Chodokufa, Kudakwashe
- Date: 2019
- Subjects: Industrial management -- Zimbabwe , Mineral industries -- Zimbabwe -- Management , Investments, Chinese -- Zimbabwe
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115127 , vital:34080
- Description: Media reports and research has pointed out problems in the way that Chinese mining organisations in Zimbabwe are managing stakeholder relationships. The problems ranging from disgruntled communities and allegations of labour violations. Taking into account the impact that China’s FDI has had on the ailing Zimbabwean economy research into the management of stakeholder relationships becomes imperative to understand how Chinese mining organisations build and manage stakeholder relationships. A review of stakeholder theory has revealed that there is not much emphasis by researchers on how organisations manage their stakeholder relationships, but rather on the identification and analysis of stakeholders. Research that has focused on stakeholder relationships has focused on different elements found in stakeholder relationship management and not necessarily on how stakeholder relationships should be managed. On the other hand, stakeholder theory does not seem to include social licence to operate which is important in stakeholder relationship management within the mining context. The purpose of this study is to develop a multidimensional stakeholder relationship management process for the Chinese mining organisation in Zimbabwe, showing dynamic interactions between multiple stakeholder networks with complementary, competitive and/or cooperative interests, while taking into account the possibility that interests may vary according to the underlying context. Thirteen semi-structured in-depth interviews were conducted with three stakeholder groups of a Chinese mining organisation as identified from the literature, namely employees, government and the community. The critical incident technique (CIT) was adopted in developing the interview questions and facilitated the data collection process. Participants described 36 critical incidents. According to multiple stakeholders, the findings suggest that, the Chinese managers built the relationship with multiple stakeholders through friendship, negotiation, pretend not to understand, referral, singing a contract, started with problems, they just arrived and through the government. With the same relationship being managed by the Chinese managers by being hard, rough and ruthless, authoritative, Chinese way of doing things, used avoidance, lack of competency, through a third party and resolving conflict when managing stakeholder relationships. Showing that the building and managing of stakeholder relationships is socially constructed and experienced differently by stakeholders. The positive and negative relationship characteristics influenced how stakeholder relationships are managed by the selected Chinese mining organisation. In the presence of positive relationship characteristics which included, friendship,there was flexibility, power dynamics, accountability depends on situations, commitment a show of investment, do cooperate to a certain extent, trust began with an open mind, shared values: hardwork and profit, shared values: culture was associated with the Chinese managing the relationship through being kind, supportive, motivating and understanding; complaint; through a third party; controlling; Chinese way of doing things; and performance and reward management of stakeholder relationships. Whilst negative relationship characteristics which included fear, their hearts were hardened, Chinese had power, intimidaton, not accountable, lack of commitment, communication understanding, connotations and intretations, communication done through a third party; no cooperation want to cut coners; trust are they conveying what is being said; deception and misrepresentation; trust depends on experience; being told lies and not transparent were associated with negative (being authoritative; hard, rough and ruthless; avoidance; blame shifting and pushy) stakeholder relationship management by the Chinese managers. Hence, a proposition that negative or positive relationship characteristics result in negative or positive stakeholder relationship management by the Chinese managers was propossed. The following challenges were experienced in the management of stakeholder relationships namely, communication, corruption, cheating, political environment, working conditions and broken promises. The dynamic multidimensional stakeholder relationship management process was subsequently revised to accommodate the new relationship characteristics and their positive and negative influence on how stakeholder relationships are managed. The main contribution of this study is the dynamic multidimensional stakeholder relationship management process which was developed within the context of a Chinese mining organisation in Africa. It is recommended that practitioners utilise the dynamic multidimensional stakeholder relationship management process to assist them in understanding and conducting research on stakeholder relationships. Further research is suggested on developing the research proposition made in the study and to empirically test the dynamic multidimension stakeholder relationship management process in other industries that posses different or similar contexts as this study.
- Full Text:
- Date Issued: 2019
- Authors: Chodokufa, Kudakwashe
- Date: 2019
- Subjects: Industrial management -- Zimbabwe , Mineral industries -- Zimbabwe -- Management , Investments, Chinese -- Zimbabwe
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/115127 , vital:34080
- Description: Media reports and research has pointed out problems in the way that Chinese mining organisations in Zimbabwe are managing stakeholder relationships. The problems ranging from disgruntled communities and allegations of labour violations. Taking into account the impact that China’s FDI has had on the ailing Zimbabwean economy research into the management of stakeholder relationships becomes imperative to understand how Chinese mining organisations build and manage stakeholder relationships. A review of stakeholder theory has revealed that there is not much emphasis by researchers on how organisations manage their stakeholder relationships, but rather on the identification and analysis of stakeholders. Research that has focused on stakeholder relationships has focused on different elements found in stakeholder relationship management and not necessarily on how stakeholder relationships should be managed. On the other hand, stakeholder theory does not seem to include social licence to operate which is important in stakeholder relationship management within the mining context. The purpose of this study is to develop a multidimensional stakeholder relationship management process for the Chinese mining organisation in Zimbabwe, showing dynamic interactions between multiple stakeholder networks with complementary, competitive and/or cooperative interests, while taking into account the possibility that interests may vary according to the underlying context. Thirteen semi-structured in-depth interviews were conducted with three stakeholder groups of a Chinese mining organisation as identified from the literature, namely employees, government and the community. The critical incident technique (CIT) was adopted in developing the interview questions and facilitated the data collection process. Participants described 36 critical incidents. According to multiple stakeholders, the findings suggest that, the Chinese managers built the relationship with multiple stakeholders through friendship, negotiation, pretend not to understand, referral, singing a contract, started with problems, they just arrived and through the government. With the same relationship being managed by the Chinese managers by being hard, rough and ruthless, authoritative, Chinese way of doing things, used avoidance, lack of competency, through a third party and resolving conflict when managing stakeholder relationships. Showing that the building and managing of stakeholder relationships is socially constructed and experienced differently by stakeholders. The positive and negative relationship characteristics influenced how stakeholder relationships are managed by the selected Chinese mining organisation. In the presence of positive relationship characteristics which included, friendship,there was flexibility, power dynamics, accountability depends on situations, commitment a show of investment, do cooperate to a certain extent, trust began with an open mind, shared values: hardwork and profit, shared values: culture was associated with the Chinese managing the relationship through being kind, supportive, motivating and understanding; complaint; through a third party; controlling; Chinese way of doing things; and performance and reward management of stakeholder relationships. Whilst negative relationship characteristics which included fear, their hearts were hardened, Chinese had power, intimidaton, not accountable, lack of commitment, communication understanding, connotations and intretations, communication done through a third party; no cooperation want to cut coners; trust are they conveying what is being said; deception and misrepresentation; trust depends on experience; being told lies and not transparent were associated with negative (being authoritative; hard, rough and ruthless; avoidance; blame shifting and pushy) stakeholder relationship management by the Chinese managers. Hence, a proposition that negative or positive relationship characteristics result in negative or positive stakeholder relationship management by the Chinese managers was propossed. The following challenges were experienced in the management of stakeholder relationships namely, communication, corruption, cheating, political environment, working conditions and broken promises. The dynamic multidimensional stakeholder relationship management process was subsequently revised to accommodate the new relationship characteristics and their positive and negative influence on how stakeholder relationships are managed. The main contribution of this study is the dynamic multidimensional stakeholder relationship management process which was developed within the context of a Chinese mining organisation in Africa. It is recommended that practitioners utilise the dynamic multidimensional stakeholder relationship management process to assist them in understanding and conducting research on stakeholder relationships. Further research is suggested on developing the research proposition made in the study and to empirically test the dynamic multidimension stakeholder relationship management process in other industries that posses different or similar contexts as this study.
- Full Text:
- Date Issued: 2019
Static and bootstrapped neuro-simulation for complex robots in evolutionary robotics
- Authors: Woodford, Grant Warren
- Date: 2019
- Subjects: Robotics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44656 , vital:38172
- Description: Evolutionary Robotics (ER) is a field of study focused on the automatic development of controllers and robot morphologies. Evolving controllers on real-world hardware is time-consuming and can damage hardware through wear. Robotic simulators can be used as an alternative to a real-world robot in order to speed up the ER process. Most simulation techniques in practice use physics-based models that rely on an understanding of the robotic system in question. Developing effective physics-based simulators is time consuming and requires a significant level of specialised knowledge. A lengthy simulator development and tuning process is typically required before the ER process can begin. Artificial Neural Networks simulators (SNNs) can be used as an alternative to a physics based simulation approach. SNNs are simple to construct, do not require significant levels of prior knowledge of the robotic system, are computationally efficient and can be highly accurate. Two types of ER approaches utilising SNNs exist. The Static Neuro-Simulation (SNS) approach involves developing SNNs before the ER process where these SNNs are used instead of a physics-based simulator. Alternatively, SNNs can be developed during the ER process, called the Bootstrapped Neuro-Simulation (BNS) approach. Prior work investigating SNNs has largely been limited to simple robots. A complex robot has many degrees of freedom and ifa low-level controller design is used, the solution search space is high-dimensional and difficult to traverse. Prior work investigating the SNS and BNS approaches have mostly relied on simplified controller designs which rely on built-in prior knowledge of intended robot behaviours. This research uses low-level controller designs which in turn rely on low level simulators. Most ER studies are conducted on a single type of robot morphology. This research investigates the SNS and BNS approaches on two significantly different classes of robots. A Hexapod and Snake robot are used to study the SNS and BNS approaches. The Hexapod robot exhibits limbed, walking behaviours. The Snake robot is limbless and generates crawling behaviours. Demonstrating the viability of the SNS and BNS approaches for two different classes of robots provides strong evidence that the tested approaches are likely viable on other classes of robots. Various proposed improvements to the SNS and BNS approaches are investigated. The Results demonstrate that the SNS and BNS approaches are viable when applied to Hexapod and Snake robots without restricting controller designs to those with significant levels of built-in prior knowledge of robot behaviours. SNNs configured in ensembles improve the likely performance outcomes of solutions. The expected benefit of adding simulator noise during the evolutionary process were not as pronounced for problems investigated in this work.
- Full Text:
- Date Issued: 2019
- Authors: Woodford, Grant Warren
- Date: 2019
- Subjects: Robotics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44656 , vital:38172
- Description: Evolutionary Robotics (ER) is a field of study focused on the automatic development of controllers and robot morphologies. Evolving controllers on real-world hardware is time-consuming and can damage hardware through wear. Robotic simulators can be used as an alternative to a real-world robot in order to speed up the ER process. Most simulation techniques in practice use physics-based models that rely on an understanding of the robotic system in question. Developing effective physics-based simulators is time consuming and requires a significant level of specialised knowledge. A lengthy simulator development and tuning process is typically required before the ER process can begin. Artificial Neural Networks simulators (SNNs) can be used as an alternative to a physics based simulation approach. SNNs are simple to construct, do not require significant levels of prior knowledge of the robotic system, are computationally efficient and can be highly accurate. Two types of ER approaches utilising SNNs exist. The Static Neuro-Simulation (SNS) approach involves developing SNNs before the ER process where these SNNs are used instead of a physics-based simulator. Alternatively, SNNs can be developed during the ER process, called the Bootstrapped Neuro-Simulation (BNS) approach. Prior work investigating SNNs has largely been limited to simple robots. A complex robot has many degrees of freedom and ifa low-level controller design is used, the solution search space is high-dimensional and difficult to traverse. Prior work investigating the SNS and BNS approaches have mostly relied on simplified controller designs which rely on built-in prior knowledge of intended robot behaviours. This research uses low-level controller designs which in turn rely on low level simulators. Most ER studies are conducted on a single type of robot morphology. This research investigates the SNS and BNS approaches on two significantly different classes of robots. A Hexapod and Snake robot are used to study the SNS and BNS approaches. The Hexapod robot exhibits limbed, walking behaviours. The Snake robot is limbless and generates crawling behaviours. Demonstrating the viability of the SNS and BNS approaches for two different classes of robots provides strong evidence that the tested approaches are likely viable on other classes of robots. Various proposed improvements to the SNS and BNS approaches are investigated. The Results demonstrate that the SNS and BNS approaches are viable when applied to Hexapod and Snake robots without restricting controller designs to those with significant levels of built-in prior knowledge of robot behaviours. SNNs configured in ensembles improve the likely performance outcomes of solutions. The expected benefit of adding simulator noise during the evolutionary process were not as pronounced for problems investigated in this work.
- Full Text:
- Date Issued: 2019
Statistical Analysis of the Radio-Interferometric Measurement Equation, a derived adaptive weighting scheme, and applications to LOFAR-VLBI observation of the Extended Groth Strip
- Authors: Bonnassieux, Etienne
- Date: 2019
- Subjects: Radio astronomy , Astrophysics , Astrophysics -- Instruments -- Calibration , Imaging systems in astronomy , Radio interferometers , Radio telescopes , Astronomy -- Observations
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/93789 , vital:30942
- Description: J.R.R Tolkien wrote, in his Mythopoeia, that “He sees no stars who does not see them first, of living silver made that sudden burst, to flame like flowers beneath the ancient song”. In his defense of myth-making, he formulates the argument that the attribution of meaning is an act of creation - that “trees are not ‘trees’ until so named and seen” - and that this capacity for creation defines the human creature. The scientific endeavour, in this context, can be understood as a social expression of a fundamental feature of humanity, and from this endeavour flows much understanding. This thesis, one thread among many, focuses on the study of astronomical objects as seen by the radio waves they emit. What are radio waves? Electromagnetic waves were theorised by James Clerk Maxwell (Maxwell 1864) in his great theoretical contribution to modern physics, their speed matching the speed of light as measured by Ole Christensen R0mer and, later, James Bradley. It was not until Heinrich Rudolf Hertz’s 1887 experiment that these waves were measured in a laboratory, leading to the dawn of radio communications - and, later, radio astronomy. The link between radio waves and light was one of association: light is known to behave as a wave (Young double-slit experiment), with the same propagation speed as electromagnetic radiation. Light “proper” is also known to exist beyond the optical regime: Herschel’s experiment shows that when diffracted through a prism, sunlight warms even those parts of a desk which are not observed to be lit (first evidence of infrared light). The link between optical light and unseen electromagnetic radiation is then an easy step to make, and one confirmed through countless technological applications (e.g. optical fiber to name but one). And as soon as this link is established, a question immediately comes to the mind of the astronomer: what does the sky, our Universe, look like to the radio “eye”? Radio astronomy has a short but storied history: from Karl Jansky’s serendipitous observation of the centre of the Milky Way, which outshines our Sun in the radio regime, in 1933, to Grote Reber’s hand-built back-yard radio antenna in 1937, which successfully detected radio emission from the Milky Way itself, to such monumental projects as the Square Kilometer Array and its multiple pathfinders, it has led to countless discoveries and the opening of a truly new window on the Universe. The work presented in this thesis is a contribution to this discipline - the culmination of three years of study, which is a rather short time to get a firm grasp of radio interferometry both in theory and in practice. The need for robust, automated methods - which are improving daily, thanks to the tireless labour of the scientists in the field - is becoming ever stronger as the SKA approaches, looming large on the horizon; but even today, in the precursor era of LOFAR, MeerKAT and other pathfinders, it is keenly felt. When I started my doctorate, the sheer scale of the task at hand felt overwhelming - to actually be able to contribute to its resolution seemed daunting indeed! Thankfully, as the saying goes, no society sets for itself material goals which it cannot achieve. This thesis took place at an exciting time for radio interferometry: at the start of my doctorate, the LOFAR international stations were - to my knowledge - only beginning to be used, and even then, only tentatively; MeerKAT had not yet shown its first light; the techniques used throughout my work were still being developed. At the time of writing, great strides have been made. One of the greatest technical challenges of LOFAR - imaging using the international stations - is starting to become reality. This technical challenge is the key problem that this thesis set out to address. While we only achieved partial success so far, it is a testament to the difficulty of the task that it is not yet truly resolved. One of the major results of this thesis is a model of a bright resolved source near a famous extragalactic field: properly modeling this source not only allows the use of international LOFAR stations, but also grants deeper access to the extragalactic field itself, which is otherwise polluted by the 3C source’s sidelobes. This result was only achieved thanks to the other major result of this thesis: the development of a theoretical framework with which to better understand the effect of calibration errors on images made from interferometric data, and an algorithm to strongly mitigate them. The structure of this manuscript is as follows: we begin with an introduction to radio interferometry, LOFAR, and the emission mechanisms which dominate for our field of interest. These introductions are primarily intended to give a brief overview of the technical aspects of the data reduced in this thesis. We follow with an overview of the Measurement Equation formalism, which underpins our theoretical work. This is the keystone of this thesis. We then show the theoretical work that was developed as part of the research work done during the doctorate - which was published in Astronomy & Astrophysics. Its practical application - a quality-based weighting scheme - is used throughout our data reduction. This data reduction is the next topic of this thesis: we contextualise the scientific interest of the data we reduce, and explain both the methods and the results we achieve.
- Full Text:
- Date Issued: 2019
- Authors: Bonnassieux, Etienne
- Date: 2019
- Subjects: Radio astronomy , Astrophysics , Astrophysics -- Instruments -- Calibration , Imaging systems in astronomy , Radio interferometers , Radio telescopes , Astronomy -- Observations
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/93789 , vital:30942
- Description: J.R.R Tolkien wrote, in his Mythopoeia, that “He sees no stars who does not see them first, of living silver made that sudden burst, to flame like flowers beneath the ancient song”. In his defense of myth-making, he formulates the argument that the attribution of meaning is an act of creation - that “trees are not ‘trees’ until so named and seen” - and that this capacity for creation defines the human creature. The scientific endeavour, in this context, can be understood as a social expression of a fundamental feature of humanity, and from this endeavour flows much understanding. This thesis, one thread among many, focuses on the study of astronomical objects as seen by the radio waves they emit. What are radio waves? Electromagnetic waves were theorised by James Clerk Maxwell (Maxwell 1864) in his great theoretical contribution to modern physics, their speed matching the speed of light as measured by Ole Christensen R0mer and, later, James Bradley. It was not until Heinrich Rudolf Hertz’s 1887 experiment that these waves were measured in a laboratory, leading to the dawn of radio communications - and, later, radio astronomy. The link between radio waves and light was one of association: light is known to behave as a wave (Young double-slit experiment), with the same propagation speed as electromagnetic radiation. Light “proper” is also known to exist beyond the optical regime: Herschel’s experiment shows that when diffracted through a prism, sunlight warms even those parts of a desk which are not observed to be lit (first evidence of infrared light). The link between optical light and unseen electromagnetic radiation is then an easy step to make, and one confirmed through countless technological applications (e.g. optical fiber to name but one). And as soon as this link is established, a question immediately comes to the mind of the astronomer: what does the sky, our Universe, look like to the radio “eye”? Radio astronomy has a short but storied history: from Karl Jansky’s serendipitous observation of the centre of the Milky Way, which outshines our Sun in the radio regime, in 1933, to Grote Reber’s hand-built back-yard radio antenna in 1937, which successfully detected radio emission from the Milky Way itself, to such monumental projects as the Square Kilometer Array and its multiple pathfinders, it has led to countless discoveries and the opening of a truly new window on the Universe. The work presented in this thesis is a contribution to this discipline - the culmination of three years of study, which is a rather short time to get a firm grasp of radio interferometry both in theory and in practice. The need for robust, automated methods - which are improving daily, thanks to the tireless labour of the scientists in the field - is becoming ever stronger as the SKA approaches, looming large on the horizon; but even today, in the precursor era of LOFAR, MeerKAT and other pathfinders, it is keenly felt. When I started my doctorate, the sheer scale of the task at hand felt overwhelming - to actually be able to contribute to its resolution seemed daunting indeed! Thankfully, as the saying goes, no society sets for itself material goals which it cannot achieve. This thesis took place at an exciting time for radio interferometry: at the start of my doctorate, the LOFAR international stations were - to my knowledge - only beginning to be used, and even then, only tentatively; MeerKAT had not yet shown its first light; the techniques used throughout my work were still being developed. At the time of writing, great strides have been made. One of the greatest technical challenges of LOFAR - imaging using the international stations - is starting to become reality. This technical challenge is the key problem that this thesis set out to address. While we only achieved partial success so far, it is a testament to the difficulty of the task that it is not yet truly resolved. One of the major results of this thesis is a model of a bright resolved source near a famous extragalactic field: properly modeling this source not only allows the use of international LOFAR stations, but also grants deeper access to the extragalactic field itself, which is otherwise polluted by the 3C source’s sidelobes. This result was only achieved thanks to the other major result of this thesis: the development of a theoretical framework with which to better understand the effect of calibration errors on images made from interferometric data, and an algorithm to strongly mitigate them. The structure of this manuscript is as follows: we begin with an introduction to radio interferometry, LOFAR, and the emission mechanisms which dominate for our field of interest. These introductions are primarily intended to give a brief overview of the technical aspects of the data reduced in this thesis. We follow with an overview of the Measurement Equation formalism, which underpins our theoretical work. This is the keystone of this thesis. We then show the theoretical work that was developed as part of the research work done during the doctorate - which was published in Astronomy & Astrophysics. Its practical application - a quality-based weighting scheme - is used throughout our data reduction. This data reduction is the next topic of this thesis: we contextualise the scientific interest of the data we reduce, and explain both the methods and the results we achieve.
- Full Text:
- Date Issued: 2019