An analysis of the countervailing measures used to address the anti-competitive effects of Government subsidies in the African Continental Free Trade Area
- Authors: Matsimbi, Rhulani Shaun
- Date: 2021-04
- Subjects: Subsidies -- Law and legislation -- Africa , Agreement on Subsidies and Countervailing Measures (1994 April 15) , Trade regulation -- Africa , World Trade Organization , Antitrust law -- Africa , Restraint of trade -- Africa , African Continental Free Trade (AfCFTA) Agreement
- Language: English
- Type: thesis , text , Masters , LLM
- Identifier: http://hdl.handle.net/10962/178330 , vital:42930
- Description: Government subsidies are becoming more prevalent on the African continent. Subsidies allow the government to intervene in markets to incentivise more investment into nascent and struggling industries by improving the efficiency of firms in such industries. As such, subsidies form an essential part of some African countries’ industrialisation policies. However, the use of subsidies faces a challenge because of the prohibition contained in the World Trade Organisation’s (WTO) Agreement on Subsidies and Countervailing Measures (SCM Agreement). The SCM Agreement prohibits the granting of subsidies that are contingent on export performance or the use of domestic over imported content. While African countries have not faced challenges in the WTO for their use of these subsidies, this may change with the operation of the African Continental Free Trade (AfCFTA) Agreement. This is because the AfCFTA Agreement localises the WTO’s rules on subsidisation. This study critically examines the provisions in the AfCFTA Guidelines on the Implementation of Trade Remedies that regulate the use of export subsidies and subsidies contingent on the use of domestic content. It discusses how the absolute prohibition of these subsidies in the AfCFTA Agreement is not the most effective way to regulate their anti-competitive effects in the African continent. Specifically, this study discusses the role that competition policy might play in ensuring that export subsidies and local content subsidies are regulated in a manner that suits Africa’s context. Ultimately, this study concludes and recommends that the AfCFTA must develop unique rules to regulate subsidies in a way that caters to the needs of the continent. , Thesis (LLM) -- Faculty of Law, Law, 2021
- Full Text:
- Authors: Matsimbi, Rhulani Shaun
- Date: 2021-04
- Subjects: Subsidies -- Law and legislation -- Africa , Agreement on Subsidies and Countervailing Measures (1994 April 15) , Trade regulation -- Africa , World Trade Organization , Antitrust law -- Africa , Restraint of trade -- Africa , African Continental Free Trade (AfCFTA) Agreement
- Language: English
- Type: thesis , text , Masters , LLM
- Identifier: http://hdl.handle.net/10962/178330 , vital:42930
- Description: Government subsidies are becoming more prevalent on the African continent. Subsidies allow the government to intervene in markets to incentivise more investment into nascent and struggling industries by improving the efficiency of firms in such industries. As such, subsidies form an essential part of some African countries’ industrialisation policies. However, the use of subsidies faces a challenge because of the prohibition contained in the World Trade Organisation’s (WTO) Agreement on Subsidies and Countervailing Measures (SCM Agreement). The SCM Agreement prohibits the granting of subsidies that are contingent on export performance or the use of domestic over imported content. While African countries have not faced challenges in the WTO for their use of these subsidies, this may change with the operation of the African Continental Free Trade (AfCFTA) Agreement. This is because the AfCFTA Agreement localises the WTO’s rules on subsidisation. This study critically examines the provisions in the AfCFTA Guidelines on the Implementation of Trade Remedies that regulate the use of export subsidies and subsidies contingent on the use of domestic content. It discusses how the absolute prohibition of these subsidies in the AfCFTA Agreement is not the most effective way to regulate their anti-competitive effects in the African continent. Specifically, this study discusses the role that competition policy might play in ensuring that export subsidies and local content subsidies are regulated in a manner that suits Africa’s context. Ultimately, this study concludes and recommends that the AfCFTA must develop unique rules to regulate subsidies in a way that caters to the needs of the continent. , Thesis (LLM) -- Faculty of Law, Law, 2021
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An investigation of support services available for black female owners of bed & breakfasts in Makhanda
- Authors: Mdluli, Lukhona Silubonile
- Date: 2021-04
- Subjects: Bed and breakfast accommodations -- South Africa -- Makhanda , Businesspeople, Black -- South Africa -- Makhanda , Business enterprises, Black -- South Africa -- Makhanda , Women-owned business enterprises -- South Africa -- Makhanda , Government aid to small business -- South Africa , Small business -- South Africa -- Makhanda , Racism -- South Africa -- Makhanda , Businesswomen -- South Africa -- Makhanda
- Language: English
- Type: thesis , text , Masters , MBA
- Identifier: http://hdl.handle.net/10962/177181 , vital:42797
- Description: Over the last 26 years, the South African government has committed to SMME development. To do this, policies and support institutions were put in place which would create a favourable environment for SMME development. This was particularly important as after 1994, when the South African economy was re-integrated into global markets after years of having sanctions imposed against the country as a result of the apartheid system. The tourism industry was identified as one of the key economic drivers which would strengthen the economy and assist in job creation, especially since South Africa would be able to attract international tourists. Further, it created the opportunity for new participants to enter the industry, including black entrepreneurs who previously could not enter the industry as a result of the apartheid laws. The opening up of the country to international markets and the focus on the tourism industry also presented the opportunity for new forms of tourism to be explored including township tourism, which gave rise to the black-owned bed & breakfast sector. Over time, it has become evident that black entrepreneurs in this sector are facing a number of challenges, in spite of the pro-SMME policies and support institutions that are in place. Because this study seeks to investigate the support services available for black female bed & breakfast owners in Makhanda, a qualitative research approach using the interpretative theoretical framework was applied. By using semi-structured interview questions, to establish what challenges do black female bed and breakfast owners face the researcher was able to respond to the following; what participants identify as their needs; and whether they are able to access the support services that are made available by the Government. Results indicated that the majority of entrepreneurs have difficulty accessing funding to develop their businesses. The seasonality of Grahamstown/ Makhanda tourism businesses has its pros and cons for tourism entrepreneurs. Despite efforts by government to transform the tourism industry, black female entrepreneurs in this industry still experience a myriad of challenges, including passive racism. Insufficient institutional support and inaccessible support services for women have made it difficult to manage in this this environment. Thus, a recommendation is put forward for female focused entrepreneurship policy, which is more responsive in terms of a judicial and legal system(s) aimed at addressing women’s particular needs and challenges. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2021
- Full Text:
- Authors: Mdluli, Lukhona Silubonile
- Date: 2021-04
- Subjects: Bed and breakfast accommodations -- South Africa -- Makhanda , Businesspeople, Black -- South Africa -- Makhanda , Business enterprises, Black -- South Africa -- Makhanda , Women-owned business enterprises -- South Africa -- Makhanda , Government aid to small business -- South Africa , Small business -- South Africa -- Makhanda , Racism -- South Africa -- Makhanda , Businesswomen -- South Africa -- Makhanda
- Language: English
- Type: thesis , text , Masters , MBA
- Identifier: http://hdl.handle.net/10962/177181 , vital:42797
- Description: Over the last 26 years, the South African government has committed to SMME development. To do this, policies and support institutions were put in place which would create a favourable environment for SMME development. This was particularly important as after 1994, when the South African economy was re-integrated into global markets after years of having sanctions imposed against the country as a result of the apartheid system. The tourism industry was identified as one of the key economic drivers which would strengthen the economy and assist in job creation, especially since South Africa would be able to attract international tourists. Further, it created the opportunity for new participants to enter the industry, including black entrepreneurs who previously could not enter the industry as a result of the apartheid laws. The opening up of the country to international markets and the focus on the tourism industry also presented the opportunity for new forms of tourism to be explored including township tourism, which gave rise to the black-owned bed & breakfast sector. Over time, it has become evident that black entrepreneurs in this sector are facing a number of challenges, in spite of the pro-SMME policies and support institutions that are in place. Because this study seeks to investigate the support services available for black female bed & breakfast owners in Makhanda, a qualitative research approach using the interpretative theoretical framework was applied. By using semi-structured interview questions, to establish what challenges do black female bed and breakfast owners face the researcher was able to respond to the following; what participants identify as their needs; and whether they are able to access the support services that are made available by the Government. Results indicated that the majority of entrepreneurs have difficulty accessing funding to develop their businesses. The seasonality of Grahamstown/ Makhanda tourism businesses has its pros and cons for tourism entrepreneurs. Despite efforts by government to transform the tourism industry, black female entrepreneurs in this industry still experience a myriad of challenges, including passive racism. Insufficient institutional support and inaccessible support services for women have made it difficult to manage in this this environment. Thus, a recommendation is put forward for female focused entrepreneurship policy, which is more responsive in terms of a judicial and legal system(s) aimed at addressing women’s particular needs and challenges. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2021
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How selected Grade 7 participants develop conceptual understanding in solving algebraic problems as a result of participating in a screencast intervention
- Authors: Wienekus, George Renier
- Date: 2021-04
- Subjects: Algebra -- Study and teaching -- South Africa , Mathematics -- Study and teaching (Elementary) -- South Africa , Problem solving in children , Algebra -- Ability testing , Algebra -- Computer-assisted instruction
- Language: English
- Type: thesis , text , Masters , MEd
- Identifier: http://hdl.handle.net/10962/176833 , vital:42763
- Description: This research project is an interventionist case study, oriented in the interpretive paradigm, which aims to investigate how selected Grade 7 participants develop conceptual understanding in solving algebraic problems as a result of participating in screencast interventions. The aim of my screencast intervention programme, which lies at the heart of this study, is to develop practices, inter alia, of how such devices and software may be “used to develop conceptual rather than procedural or decorative knowledge” (Larkin & Calder, 2015:1) in solving linear equations. The planned intervention was delivered in the form of a series of screencasts: these take the form of audio-video lessons with an emphasis on the visual impact, and were recorded using an application called Explain Everything. The screencast interventions were delivered via Google Classroom and included animations supported by such conceptual explanations of early algebra as are relevant to Grade 7 students, and in line with the South African Curriculum and Assessment Policy Statements - Department of Education, 2011. The fundamental components of an early algebraic equation that would be relevant to a Grade 7 student were considered and used to develop an analytic framework. This was based on a taxonomy designed according to four identified “clusters” in order to analyse the workings of the purposefully selected Grade 7 participants who were video recorded and questioned in a talk-aloud interview while they completed a post-intervention pencil-and-paper test. What emerges from this research project is that there is a significant need for specific and concentrated technology-based techniques, such as the interventions undertaken here, and that exploration and development in the field could benefit the delivery of a pedagogy for algebra. The pedagogical methods implemented and studied in the form of screencasts proved to be successful and were well received by the learners particularly in relation to the conceptualisation of “symbol sense” and transformation in early algebra. The structure and design of the screencast interventions were important in supporting the acquisition of these concepts and were demonstrated to be worthwhile tools for an epistemological application in a classroom or teaching context. , Thesis (MEd) -- Rhodes University, Faculty of Education, Education, 2021
- Full Text:
- Authors: Wienekus, George Renier
- Date: 2021-04
- Subjects: Algebra -- Study and teaching -- South Africa , Mathematics -- Study and teaching (Elementary) -- South Africa , Problem solving in children , Algebra -- Ability testing , Algebra -- Computer-assisted instruction
- Language: English
- Type: thesis , text , Masters , MEd
- Identifier: http://hdl.handle.net/10962/176833 , vital:42763
- Description: This research project is an interventionist case study, oriented in the interpretive paradigm, which aims to investigate how selected Grade 7 participants develop conceptual understanding in solving algebraic problems as a result of participating in screencast interventions. The aim of my screencast intervention programme, which lies at the heart of this study, is to develop practices, inter alia, of how such devices and software may be “used to develop conceptual rather than procedural or decorative knowledge” (Larkin & Calder, 2015:1) in solving linear equations. The planned intervention was delivered in the form of a series of screencasts: these take the form of audio-video lessons with an emphasis on the visual impact, and were recorded using an application called Explain Everything. The screencast interventions were delivered via Google Classroom and included animations supported by such conceptual explanations of early algebra as are relevant to Grade 7 students, and in line with the South African Curriculum and Assessment Policy Statements - Department of Education, 2011. The fundamental components of an early algebraic equation that would be relevant to a Grade 7 student were considered and used to develop an analytic framework. This was based on a taxonomy designed according to four identified “clusters” in order to analyse the workings of the purposefully selected Grade 7 participants who were video recorded and questioned in a talk-aloud interview while they completed a post-intervention pencil-and-paper test. What emerges from this research project is that there is a significant need for specific and concentrated technology-based techniques, such as the interventions undertaken here, and that exploration and development in the field could benefit the delivery of a pedagogy for algebra. The pedagogical methods implemented and studied in the form of screencasts proved to be successful and were well received by the learners particularly in relation to the conceptualisation of “symbol sense” and transformation in early algebra. The structure and design of the screencast interventions were important in supporting the acquisition of these concepts and were demonstrated to be worthwhile tools for an epistemological application in a classroom or teaching context. , Thesis (MEd) -- Rhodes University, Faculty of Education, Education, 2021
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Impact of sovereign credit ratings on emerging bond and stock market returns
- Authors: Mkhonto, Zoyisile
- Date: 2021-04
- Subjects: Rating agencies (Finance) , Credit ratings , Bond market
- Language: English
- Type: thesis , text , Masters , MCom
- Identifier: http://hdl.handle.net/10962/177170 , vital:42796
- Description: The primary role of credit rating agencies is to reduce asymmetric information between the parties in a lending relationship. The three major rating agencies have received extensive criticism over the years. These rating agencies have been accused of providing inaccurate ratings which ultimately led to various financial calamities. Late rating action has also been blamed for exacerbating financial and economic cycles. Moreover, there is an argument that emerging markets are unfairly rated in comparison to developed economies. Hence, the reliability and informational value of the assessments provided by credit rating agencies is met with scepticism. Despite these criticisms, rating agencies are characterised as gatekeepers to capital and credit ratings remain essential financial market indicators. Albeit, the literature regarding the impact of sovereign credit ratings on bond and stock markets is inconclusive. This study aims to add to the body of literature and provide insights into the informational value of sovereign credit ratings in emerging markets. More specifically to estimate the relationship between various sovereign credit rating announcements, and bond and stock market returns. Also, to examine whether sovereign credit ratings have a differential impact between bond and stock markets. As well as address the question does it matter who provides the rating? Using an event study, abnormal returns surrounding rating announcements from 2009 to 2019 for 24 emerging markets were analyzed. Firstly, this study concluded that sovereign credit ratings are informative. Secondly, the degree of informativeness differs between the bond and stock markets. Thirdly, an asymmetrical impact was observed between the types of rating announcements. Lastly, that it does matter which rating agency provides the rating because each agency has a unique reputation. The findings of this research have implications on how investors and portfolio managers decide on asset allocation. Furthermore, policymakers may find our investment grade analysis of value when evaluating regulatory reform. It’s recommended that future research refines the event methodology and examines country specific characteristics within each of the emerging markets. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2021
- Full Text:
- Authors: Mkhonto, Zoyisile
- Date: 2021-04
- Subjects: Rating agencies (Finance) , Credit ratings , Bond market
- Language: English
- Type: thesis , text , Masters , MCom
- Identifier: http://hdl.handle.net/10962/177170 , vital:42796
- Description: The primary role of credit rating agencies is to reduce asymmetric information between the parties in a lending relationship. The three major rating agencies have received extensive criticism over the years. These rating agencies have been accused of providing inaccurate ratings which ultimately led to various financial calamities. Late rating action has also been blamed for exacerbating financial and economic cycles. Moreover, there is an argument that emerging markets are unfairly rated in comparison to developed economies. Hence, the reliability and informational value of the assessments provided by credit rating agencies is met with scepticism. Despite these criticisms, rating agencies are characterised as gatekeepers to capital and credit ratings remain essential financial market indicators. Albeit, the literature regarding the impact of sovereign credit ratings on bond and stock markets is inconclusive. This study aims to add to the body of literature and provide insights into the informational value of sovereign credit ratings in emerging markets. More specifically to estimate the relationship between various sovereign credit rating announcements, and bond and stock market returns. Also, to examine whether sovereign credit ratings have a differential impact between bond and stock markets. As well as address the question does it matter who provides the rating? Using an event study, abnormal returns surrounding rating announcements from 2009 to 2019 for 24 emerging markets were analyzed. Firstly, this study concluded that sovereign credit ratings are informative. Secondly, the degree of informativeness differs between the bond and stock markets. Thirdly, an asymmetrical impact was observed between the types of rating announcements. Lastly, that it does matter which rating agency provides the rating because each agency has a unique reputation. The findings of this research have implications on how investors and portfolio managers decide on asset allocation. Furthermore, policymakers may find our investment grade analysis of value when evaluating regulatory reform. It’s recommended that future research refines the event methodology and examines country specific characteristics within each of the emerging markets. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2021
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Motivation to learn science and make sense of the concept of malleability through the traditional blast furnace in a grade 9 Physical Science class
- Authors: Kudumo, Wilfred Peter
- Date: 2021-04
- Subjects: Science -- Study and teaching (Secondary) -- Namibia -- Kavango West , Metals -- Effect of high temperatures on , Blast furnaces , Ethnoscience -- Namibia -- Kavango West , Ubuntu (Philosophy) , Culturally relevant pedagogy , Motivation in education -- Namibia -- Kavango West , Continuity Argumentative Theory (CAT)
- Language: English
- Type: thesis , text , Masters , MEd
- Identifier: http://hdl.handle.net/10962/177262 , vital:42804
- Description: The current situation of teaching and learning science in Namibia is of great concern since it does not seem to take into consideration learners’ socio-cultural backgrounds. As a result, learners are finding that science is not relevant to their everyday life experiences and hence are not motivated to learn it. This is compounded in part by the fact that the Namibian curriculum seems to be silent on how science teachers should include learners’ socio-cultural backgrounds, for example, local or indigenous knowledge in their teaching repertoires. It is against this background that in this study I explored how mobilising the cultural practice of a traditional blast furnace (mudukuto) as an approach enables and/or constrains learners’ motivation to learn science and make sense of the concept of malleability. This is a qualitative case study underpinned by a combination of interpretive and Ubuntu paradigms. It was carried out in a rural school in Namibia, Kavango West Region, where I am currently teaching. The participants in the study were grade 9 learners and one expert community member. Focus group interviews, participatory observation, learners’ reflections, and stimulated recall interviews were used to gather qualitative data. Vygotsky’s socio-cultural theory was used as a theoretical framework and Ogunniyi`s Continuity Argumentative Theory (CAT) was used as analytical framework or lens to analyse the data. A thematic approach to analyse data was employed. That is, qualitative data were analysed inductively to come up with sub-themes and themes. The findings of the study revealed that the traditional furnace motivated the learners involved in this study to learn science and learners were able to extract science concepts on malleability from the traditional practice. The implication for this study is that when science is related to learners’ daily life or real-world experiences, they are enabled to bridge the gap from what they learn at home or in the community with school science. The study thus recommends that teachers should make an effort to integrate local or indigenous knowledge and practices to make science accessible and relevant in their classrooms. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Authors: Kudumo, Wilfred Peter
- Date: 2021-04
- Subjects: Science -- Study and teaching (Secondary) -- Namibia -- Kavango West , Metals -- Effect of high temperatures on , Blast furnaces , Ethnoscience -- Namibia -- Kavango West , Ubuntu (Philosophy) , Culturally relevant pedagogy , Motivation in education -- Namibia -- Kavango West , Continuity Argumentative Theory (CAT)
- Language: English
- Type: thesis , text , Masters , MEd
- Identifier: http://hdl.handle.net/10962/177262 , vital:42804
- Description: The current situation of teaching and learning science in Namibia is of great concern since it does not seem to take into consideration learners’ socio-cultural backgrounds. As a result, learners are finding that science is not relevant to their everyday life experiences and hence are not motivated to learn it. This is compounded in part by the fact that the Namibian curriculum seems to be silent on how science teachers should include learners’ socio-cultural backgrounds, for example, local or indigenous knowledge in their teaching repertoires. It is against this background that in this study I explored how mobilising the cultural practice of a traditional blast furnace (mudukuto) as an approach enables and/or constrains learners’ motivation to learn science and make sense of the concept of malleability. This is a qualitative case study underpinned by a combination of interpretive and Ubuntu paradigms. It was carried out in a rural school in Namibia, Kavango West Region, where I am currently teaching. The participants in the study were grade 9 learners and one expert community member. Focus group interviews, participatory observation, learners’ reflections, and stimulated recall interviews were used to gather qualitative data. Vygotsky’s socio-cultural theory was used as a theoretical framework and Ogunniyi`s Continuity Argumentative Theory (CAT) was used as analytical framework or lens to analyse the data. A thematic approach to analyse data was employed. That is, qualitative data were analysed inductively to come up with sub-themes and themes. The findings of the study revealed that the traditional furnace motivated the learners involved in this study to learn science and learners were able to extract science concepts on malleability from the traditional practice. The implication for this study is that when science is related to learners’ daily life or real-world experiences, they are enabled to bridge the gap from what they learn at home or in the community with school science. The study thus recommends that teachers should make an effort to integrate local or indigenous knowledge and practices to make science accessible and relevant in their classrooms. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
Night-time gravity waves detected with multi-frequency airglow imager
- Authors: Machubeng, Karabo Pebane
- Date: 2021-04
- Subjects: Gravity waves , Airglow , Gravity waves -- Seasonal variations , All Sky Imager
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178341 , vital:42931
- Description: This thesis shows the statistics of atmospheric gravity waves (AGWs) observed in the OI emission 557.7 nm at _97 km altitude using an all-sky imager based in Sutherland, South Africa (32.37_ S, 20.81_ E) in the year 2017. The wavelengths were determined using the propagation vector method, velocity was determined using the cross correlation of 1D FFT and the period was determined using the equation that relates wavelength and velocity. It was found that the horizontal wavelength in summer was almost evenly distributed between 10 and 40 km and for autumn, winter and spring were mostly between 10 and 30 km. The favoured speeds were between 40 and 50 m/s in autumn, as well as 30 and 50 m/s in summer, but the AGWs in winter had a bimodal speed distribution of 20 - 40 and 50 - 70 m/s. The majority of periods observed in all seasons were less than 20 minutes with a dominant peak of 5 - 10 minutes in autumn and spring. There was no favoured propagation direction for spring, but AGWs favoured a southeastward propagation in summer, and a southward propagation in autumn and winter. , Thesis (MSc) -- Faculty of Science, Physics and Electronics, 2021
- Full Text:
- Authors: Machubeng, Karabo Pebane
- Date: 2021-04
- Subjects: Gravity waves , Airglow , Gravity waves -- Seasonal variations , All Sky Imager
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/178341 , vital:42931
- Description: This thesis shows the statistics of atmospheric gravity waves (AGWs) observed in the OI emission 557.7 nm at _97 km altitude using an all-sky imager based in Sutherland, South Africa (32.37_ S, 20.81_ E) in the year 2017. The wavelengths were determined using the propagation vector method, velocity was determined using the cross correlation of 1D FFT and the period was determined using the equation that relates wavelength and velocity. It was found that the horizontal wavelength in summer was almost evenly distributed between 10 and 40 km and for autumn, winter and spring were mostly between 10 and 30 km. The favoured speeds were between 40 and 50 m/s in autumn, as well as 30 and 50 m/s in summer, but the AGWs in winter had a bimodal speed distribution of 20 - 40 and 50 - 70 m/s. The majority of periods observed in all seasons were less than 20 minutes with a dominant peak of 5 - 10 minutes in autumn and spring. There was no favoured propagation direction for spring, but AGWs favoured a southeastward propagation in summer, and a southward propagation in autumn and winter. , Thesis (MSc) -- Faculty of Science, Physics and Electronics, 2021
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Photodynamic antimicrobial chemotherapy against Staphylococcus aureus and Escherichia coli sensitized using indium (III) cationic porphyrins linked to core-shell magnetic nanoparticles
- Authors: Makola, Lekgowa Collen
- Date: 2021-04
- Subjects: Photochemotherapy , Photosensitizing compounds , Staphylococcus aureus , Escherichia coli , Indium , Porphyrins , Magnetic nanoparticles , Quaternize
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177225 , vital:42801
- Description: Photodynamic antimicrobial chemotherapy (PACT) is a well-known antimicrobial therapy technique used against multi-drug resistant pathogens. In this study, the syntheses, characterization, photophysicochemical properties, and the applications of symmetrically and asymmetrically substituted cationic indium (III) porphyrins linked to silver/copper ferrite core-shell (Ag/CuFe2O4) magnetic nanoparticles (MNPs) as potential photosensitizers for PACT are reported. The synthesized complexes include axially modified porphyrins quaternized through an axial ligand. All the asymmetrically substituted porphyrins were linked to the NPs via an ester bond and the symmetrically substituted porphyrins were linked (peripherally and /or axially) via self-assembly (Ag-S and/or Ag-N). The impact of axial modification, peripheral substituents, conjugation to the NPs, the number of positive charges, and the chain length of the alkyl halides quaternizing agents on PACT efficacy and photophysicochemical properties of porphyrins were studied. High singlet oxygen quantum yields and antimicrobial log reductions were observed. Lipophilicity and hydrophilicity of the porphyrins were also studies, where the complexes quaternized with methyl iodide showed relatively high hydrophilicity character. Upon in vitro PACT studies, the quaternized complexes were observed to have 0% viable colony, signifying their effectiveness. Moreover, the highest log reductions of 9.27 were observed against S. aureus and 9.58 were observed against E. coli. The findings from this work delineate that singlet oxygen generation alone is not a distinct factor on the PACT efficacy of the porphyrin complexes, since some of the complexes have practically the same singlet oxygen quantum but different PACT activity. However, other contributing factors including water solubility play a significant role. , Thesis (MSc) -- Faculty of Science, Department of Chemistry, 2021
- Full Text:
- Authors: Makola, Lekgowa Collen
- Date: 2021-04
- Subjects: Photochemotherapy , Photosensitizing compounds , Staphylococcus aureus , Escherichia coli , Indium , Porphyrins , Magnetic nanoparticles , Quaternize
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/177225 , vital:42801
- Description: Photodynamic antimicrobial chemotherapy (PACT) is a well-known antimicrobial therapy technique used against multi-drug resistant pathogens. In this study, the syntheses, characterization, photophysicochemical properties, and the applications of symmetrically and asymmetrically substituted cationic indium (III) porphyrins linked to silver/copper ferrite core-shell (Ag/CuFe2O4) magnetic nanoparticles (MNPs) as potential photosensitizers for PACT are reported. The synthesized complexes include axially modified porphyrins quaternized through an axial ligand. All the asymmetrically substituted porphyrins were linked to the NPs via an ester bond and the symmetrically substituted porphyrins were linked (peripherally and /or axially) via self-assembly (Ag-S and/or Ag-N). The impact of axial modification, peripheral substituents, conjugation to the NPs, the number of positive charges, and the chain length of the alkyl halides quaternizing agents on PACT efficacy and photophysicochemical properties of porphyrins were studied. High singlet oxygen quantum yields and antimicrobial log reductions were observed. Lipophilicity and hydrophilicity of the porphyrins were also studies, where the complexes quaternized with methyl iodide showed relatively high hydrophilicity character. Upon in vitro PACT studies, the quaternized complexes were observed to have 0% viable colony, signifying their effectiveness. Moreover, the highest log reductions of 9.27 were observed against S. aureus and 9.58 were observed against E. coli. The findings from this work delineate that singlet oxygen generation alone is not a distinct factor on the PACT efficacy of the porphyrin complexes, since some of the complexes have practically the same singlet oxygen quantum but different PACT activity. However, other contributing factors including water solubility play a significant role. , Thesis (MSc) -- Faculty of Science, Department of Chemistry, 2021
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The development of an ionospheric storm-time index for the South African region
- Authors: Tshisaphungo, Mpho
- Date: 2021-04
- Subjects: Ionospheric storms -- South Africa , Global Positioning System , Neural networks (Computer science) , Regression analysis , Ionosondes , Auroral electrojet , Geomagnetic indexes , Magnetic storms -- South Africa
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178409 , vital:42937 , 10.21504/10962/178409
- Description: This thesis presents the development of a regional ionospheric storm-time model which forms the foundation of an index to provide a quick view of the ionospheric storm effects over South African mid-latitude region. The model is based on the foF2 measurements from four South African ionosonde stations. The data coverage for the model development over Grahamstown (33.3◦S, 26.5◦E), Hermanus (34.42◦S, 19.22◦E), Louisvale (28.50◦S, 21.20◦E), and Madimbo (22.39◦S, 30.88◦E) is 1996-2016, 2009-2016, 2000-2016, and 2000-2016 respectively. Data from the Global Positioning System (GPS) and radio occultation (RO) technique were used during validation. As the measure of either positive or negative storm effect, the variation of the critical frequency of the F2 layer (foF2) from the monthly median values (denoted as _foF2) is modeled. The modeling of _foF2 is based on only storm time data with the criteria of Dst 6 -50 nT and Kp > 4. The modeling methods used in the study were artificial neural network (ANN), linear regression (LR) and polynomial functions. The approach taken was to first test the modeling techniques on a single station before expanding the study to cover the regional aspect. The single station modeling was developed based on ionosonde data over Grahamstown. The inputs for the model which related to seasonal variation, diurnal variation, geomagnetic activity and solar activity were considered. For the geomagnetic activity, three indices namely; the symmetric disturbance in the horizontal component of the Earth’s magnetic field (SYM − H), the Auroral Electrojet (AE) index and local geomagnetic index A, were included as inputs. The performance of a single station model revealed that, of the three geomagnetic indices, SYM − H index has the largest contribution of 41% and 54% based on ANN and LR techniques respectively. The average correlation coefficients (R) for both ANN and LR models was 0.8, when validated during the selected storms falling within the period of model development. When validated using storms that fall outside the period of model development, the model gave R values of 0.6 and 0.5 for ANN and LR respectively. In addition, the GPS total electron content (TEC) derived measurements were used to estimate foF2 data. This is because there are more GPS receivers than ionosonde locations and the utilisation of this data increases the spatial coverage of the regional model. The estimation of foF2 from GPS TEC was done at GPS-ionosonde co-locations using polynomial functions. The average R values of 0.69 and 0.65 were obtained between actual and derived _foF2 over the co-locations and other GPS stations respectively. Validation of GPS TEC derived foF2 with RO data over regions out of ionospheric pierce points coverage with respect to ionosonde locations gave R greater than 0.9 for the selected storm period of 4-8 August 2011. The regional storm-time model was then developed based on the ANN technique using the four South African ionosonde stations. The maximum and minimum R values of 0.6 and 0.5 were obtained over ionosonde and GPS locations respectively. This model forms the basis towards the regional ionospheric storm-time index. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2021
- Full Text:
- Authors: Tshisaphungo, Mpho
- Date: 2021-04
- Subjects: Ionospheric storms -- South Africa , Global Positioning System , Neural networks (Computer science) , Regression analysis , Ionosondes , Auroral electrojet , Geomagnetic indexes , Magnetic storms -- South Africa
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178409 , vital:42937 , 10.21504/10962/178409
- Description: This thesis presents the development of a regional ionospheric storm-time model which forms the foundation of an index to provide a quick view of the ionospheric storm effects over South African mid-latitude region. The model is based on the foF2 measurements from four South African ionosonde stations. The data coverage for the model development over Grahamstown (33.3◦S, 26.5◦E), Hermanus (34.42◦S, 19.22◦E), Louisvale (28.50◦S, 21.20◦E), and Madimbo (22.39◦S, 30.88◦E) is 1996-2016, 2009-2016, 2000-2016, and 2000-2016 respectively. Data from the Global Positioning System (GPS) and radio occultation (RO) technique were used during validation. As the measure of either positive or negative storm effect, the variation of the critical frequency of the F2 layer (foF2) from the monthly median values (denoted as _foF2) is modeled. The modeling of _foF2 is based on only storm time data with the criteria of Dst 6 -50 nT and Kp > 4. The modeling methods used in the study were artificial neural network (ANN), linear regression (LR) and polynomial functions. The approach taken was to first test the modeling techniques on a single station before expanding the study to cover the regional aspect. The single station modeling was developed based on ionosonde data over Grahamstown. The inputs for the model which related to seasonal variation, diurnal variation, geomagnetic activity and solar activity were considered. For the geomagnetic activity, three indices namely; the symmetric disturbance in the horizontal component of the Earth’s magnetic field (SYM − H), the Auroral Electrojet (AE) index and local geomagnetic index A, were included as inputs. The performance of a single station model revealed that, of the three geomagnetic indices, SYM − H index has the largest contribution of 41% and 54% based on ANN and LR techniques respectively. The average correlation coefficients (R) for both ANN and LR models was 0.8, when validated during the selected storms falling within the period of model development. When validated using storms that fall outside the period of model development, the model gave R values of 0.6 and 0.5 for ANN and LR respectively. In addition, the GPS total electron content (TEC) derived measurements were used to estimate foF2 data. This is because there are more GPS receivers than ionosonde locations and the utilisation of this data increases the spatial coverage of the regional model. The estimation of foF2 from GPS TEC was done at GPS-ionosonde co-locations using polynomial functions. The average R values of 0.69 and 0.65 were obtained between actual and derived _foF2 over the co-locations and other GPS stations respectively. Validation of GPS TEC derived foF2 with RO data over regions out of ionospheric pierce points coverage with respect to ionosonde locations gave R greater than 0.9 for the selected storm period of 4-8 August 2011. The regional storm-time model was then developed based on the ANN technique using the four South African ionosonde stations. The maximum and minimum R values of 0.6 and 0.5 were obtained over ionosonde and GPS locations respectively. This model forms the basis towards the regional ionospheric storm-time index. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2021
- Full Text:
Using the indigenous technology of dyeing and weaving African baskets as a cultural tool to mediate learning of chemical and physical changes
- Authors: Kakambi, William Mafelezo
- Date: 2021-04
- Subjects: Science -- Study and teaching (Secondary) -- Namibia , Chemistry -- Study and teaching (Secondary) -- Namibia , Ethnoscience -- Namibia , Culturally relevant pedagogy , Traditional ecological knowledge -- Namibia , Basket making -- Namibia , Dyes and dyeing -- Namibia , Pedagogical content knowledge
- Language: English
- Type: thesis , text , Masters , MEd
- Identifier: http://hdl.handle.net/10962/177268 , vital:42805
- Description: Literature has revealed that indigenous learners, especially in many African nations are subjected to learning school science in unfamiliar contexts. Learners in Namibia where this study was conducted are no exception. In consequence, learners experience cognitive conflict between school science and the experiences learnt at home and in the community. This is exacerbated, in part, by the fact that science teachers do not seem to know how to integrate indigenous knowledge in their science teaching. As an attempt to address this problem, some scholars call for the integration of indigenous knowledge into the science curriculum to provide a much needed context for learning science. It is against this background that this study sought to use the indigenous technology of dyeing and weaving baskets as a cultural tool to mediate learning of chemical and physical changes. Underpinned by the interpretivist and Ubuntu paradigms, the study employed a qualitative case study research design. The study was conducted in the Zambezi region in Namibia. Four grade 8 Physical Science teachers, an expert community member, and a critical friend were involved as participants in this study. Data were gathered using semi-structured interviews, workshop discussions, participatory observation, and journal reflections. Vygotsky’s socio-cultural theory and Mavhunga and Rollnick’s topic specific pedagogical content knowledge were used as theoretical and analytical frameworks, respectively. A thematic approach to data analysis was employed to come up with sub-themes and themes. The findings of the study revealed that all the participating teachers in this study had never been exposed to ideas on how to integrate indigenous knowledge in their science teaching. As a result, they all embraced and valued the indigenous technology of dyeing and weaving as relevant and useful in the teaching and learning of chemical and physical changes. This study recommends that there is a need to empower science teachers on how to integrate indigenous knowledge in their science teaching in order to make science accessible and relevant to their learners’ lived worlds. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Authors: Kakambi, William Mafelezo
- Date: 2021-04
- Subjects: Science -- Study and teaching (Secondary) -- Namibia , Chemistry -- Study and teaching (Secondary) -- Namibia , Ethnoscience -- Namibia , Culturally relevant pedagogy , Traditional ecological knowledge -- Namibia , Basket making -- Namibia , Dyes and dyeing -- Namibia , Pedagogical content knowledge
- Language: English
- Type: thesis , text , Masters , MEd
- Identifier: http://hdl.handle.net/10962/177268 , vital:42805
- Description: Literature has revealed that indigenous learners, especially in many African nations are subjected to learning school science in unfamiliar contexts. Learners in Namibia where this study was conducted are no exception. In consequence, learners experience cognitive conflict between school science and the experiences learnt at home and in the community. This is exacerbated, in part, by the fact that science teachers do not seem to know how to integrate indigenous knowledge in their science teaching. As an attempt to address this problem, some scholars call for the integration of indigenous knowledge into the science curriculum to provide a much needed context for learning science. It is against this background that this study sought to use the indigenous technology of dyeing and weaving baskets as a cultural tool to mediate learning of chemical and physical changes. Underpinned by the interpretivist and Ubuntu paradigms, the study employed a qualitative case study research design. The study was conducted in the Zambezi region in Namibia. Four grade 8 Physical Science teachers, an expert community member, and a critical friend were involved as participants in this study. Data were gathered using semi-structured interviews, workshop discussions, participatory observation, and journal reflections. Vygotsky’s socio-cultural theory and Mavhunga and Rollnick’s topic specific pedagogical content knowledge were used as theoretical and analytical frameworks, respectively. A thematic approach to data analysis was employed to come up with sub-themes and themes. The findings of the study revealed that all the participating teachers in this study had never been exposed to ideas on how to integrate indigenous knowledge in their science teaching. As a result, they all embraced and valued the indigenous technology of dyeing and weaving as relevant and useful in the teaching and learning of chemical and physical changes. This study recommends that there is a need to empower science teachers on how to integrate indigenous knowledge in their science teaching in order to make science accessible and relevant to their learners’ lived worlds. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
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