Mineralogy, geochemistry and origin of the Neoproterozoic Xaudum iron-formation in Botswana
- Authors: Ntantiso, Mawande
- Date: 2020
- Subjects: Xaudum iron-formation , Iron ores -- Botswana , Formations (Geology) -- Botswana , Mineralogy -- Botswana , Paleoclimatology -- Proterozoic
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167211 , vital:41447
- Description: Banded iron-formations (BIF) formed in three different geological periods in the Earth’s history, namely the Archean, Paleoproterozoic and Neoproterozoic. Each of these periods has a corresponding index BIF type attributed to them. The oldest is the Archean Algoma-type BIF which is typically dominated by smaller-volume BIF deposits associated with volcanic rocks and greenstone belts. The next is the volumetrically far more abundant Superior-type BIF of the Paleoproterozoic lacking any obvious volcanic relation. The youngest BIFs were deposited after a hiatus of a billion years in the Neoproterozoic and are believed to be genetically linked to Marinoan ice-age. The global re-introduction and distribution of BIF in the Neoproterozoic highlights a shift in the Earth’s tectonics, climate, biosphere and ocean chemistry from the older Archean and Paleoproterozoic counterparts. Various models have been postulated by researchers in attempts to explain how Neoproterozoic iron-formations formed. In all the available models, the Snowball Earth Hypothesis initially proposed by Kirshvink (1992) is an overarching concept. In this study, four cores from the Neoproterozoic Xaudum iron-formation (XIF) in Ngamiland, northwest of Botswana, were sampled and analysed following a partnership between Postgraduate Research in Iron and Manganese Ore Resources (PRIMOR) and Tsodilo Resources Ltd. The study sets out to explore the mineralogy and chemistry of XIF in order to determine its origin, constrain the redox conditions in the paleo-basin, assess it in the context of other Neoproterozoic iron-formations and older Archean and Paleoproterozoic iron-formations, and inform metallurgical processing. The mineralogy of XIF consists of magnetite, quartz, amphibole, garnet, biotite and chlorite in decreasing abundance. This mineral assemblage is characteristic of medium grade metamorphosed iron-formations. Algoma and Superior-type BIFs which experienced late-diagenetic and very low-grade metamorphism have a complex mineral assemblage consisting of hematite, magnetite, quartz, and several carbonate (dolomite-ankerite series and siderite) and silicate phases (greenalite, riebeckite and stilpnomelane). The geochemical results show that XIF has higher Mn3O4 and Al2O3 average contents when compared to Algoma and Superior type BIF. The detrital components in XIF correlate with High Field Strength Elements (HFSE) suggesting increased delivery of siliciclastic material during deposition. This trend is comparable to other NIF deposits suggesting a global high input of siliciclastic material into Neoproterozoic paleodepositional environments. This trend is different from Archean and Paleoproterozoic BIF deposits which are close to pure chemical sediments lacking measurable detrital contributions. In the XIF, bulk-rock Mn3O4 and Al2O3 in drillcore SW have higher averages of 2.4 and 2.6 wt. % respectively, compared to the other three cores. The Mn3O4 shows a positive statistical relationship with Co, suggesting that Neoproterozoic oceans and atmosphere were possibly more oxic than in the Archean and Paleoproterozoic. The Mn3O4 shows an antithetic relationship with Fe2O3 suggesting that the paleobasin was chemically heterogeneous in terms of redox conditions, with Fe2O3 depositing presumably in deeper parts removed from a detrital source, and Mn3O4 depositing possibly more proximal to a paleo-shoreline in a shallower setting where there was higher delivery of siliciclastic material from the continent due to correspondingly higher Al2O3 and TiO2 contents. The REE patterns of XIF show positive-sloping trends of depletion in LREE and enrichment in HREE which resemble those of seawater. However, the REE slope becomes a lot flatter and resembles closer the signature of PAAS and adjacent diamictite facies, which agrees with the idea of high siliciclastic input in the paleobasin comparable to other NIF. XIF also appears to lack clear Ce or Eu anomalies. The lack of the former points to the oceans possibly not being oxic enough to drive the fractionation of Ce into Mn oxides like in the modern oceans, or that the Ce behaviour is obscured by the high siliciclastic input in XIF. Similarly, the lack of positive Eu anomaly shows a weak to absent hydrothermal signal into to modern shallow seawater where Fe and Si were sourced, or detritally derived REE contamination. Extensive weathering under hot and humid climate during glacial retreat is shown by the low K2O/Al2O3 ratios and high CIA values ranging from 80-99. Re-glaciation signifies the return of cold and arid and it is represented by high K2O/Al2O3 ratios and low CIA values ranging from 64-78. The previous genetic models of NIF by Klein (1993), Baldwin et al. (2012) and Lechte and Wallace (2015) provide an essential foundation for the development of a XIF genetic model. The genetic model of XIF proposes deposition on an open continental shelf characterized by a steady influx of detrital material. The seawater has been anoxic since the Paleoproterozoic and further induced by basin stagnation due to the ice covering the basin. Two overlapping oxidative stages are assumed for the precipitation of Fe and Mn across lateral redox gradients in the paleobasin. The exact oxidative pathways and mechanisms for the above processes remains unconstrained.
- Full Text:
- Date Issued: 2020
- Authors: Ntantiso, Mawande
- Date: 2020
- Subjects: Xaudum iron-formation , Iron ores -- Botswana , Formations (Geology) -- Botswana , Mineralogy -- Botswana , Paleoclimatology -- Proterozoic
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167211 , vital:41447
- Description: Banded iron-formations (BIF) formed in three different geological periods in the Earth’s history, namely the Archean, Paleoproterozoic and Neoproterozoic. Each of these periods has a corresponding index BIF type attributed to them. The oldest is the Archean Algoma-type BIF which is typically dominated by smaller-volume BIF deposits associated with volcanic rocks and greenstone belts. The next is the volumetrically far more abundant Superior-type BIF of the Paleoproterozoic lacking any obvious volcanic relation. The youngest BIFs were deposited after a hiatus of a billion years in the Neoproterozoic and are believed to be genetically linked to Marinoan ice-age. The global re-introduction and distribution of BIF in the Neoproterozoic highlights a shift in the Earth’s tectonics, climate, biosphere and ocean chemistry from the older Archean and Paleoproterozoic counterparts. Various models have been postulated by researchers in attempts to explain how Neoproterozoic iron-formations formed. In all the available models, the Snowball Earth Hypothesis initially proposed by Kirshvink (1992) is an overarching concept. In this study, four cores from the Neoproterozoic Xaudum iron-formation (XIF) in Ngamiland, northwest of Botswana, were sampled and analysed following a partnership between Postgraduate Research in Iron and Manganese Ore Resources (PRIMOR) and Tsodilo Resources Ltd. The study sets out to explore the mineralogy and chemistry of XIF in order to determine its origin, constrain the redox conditions in the paleo-basin, assess it in the context of other Neoproterozoic iron-formations and older Archean and Paleoproterozoic iron-formations, and inform metallurgical processing. The mineralogy of XIF consists of magnetite, quartz, amphibole, garnet, biotite and chlorite in decreasing abundance. This mineral assemblage is characteristic of medium grade metamorphosed iron-formations. Algoma and Superior-type BIFs which experienced late-diagenetic and very low-grade metamorphism have a complex mineral assemblage consisting of hematite, magnetite, quartz, and several carbonate (dolomite-ankerite series and siderite) and silicate phases (greenalite, riebeckite and stilpnomelane). The geochemical results show that XIF has higher Mn3O4 and Al2O3 average contents when compared to Algoma and Superior type BIF. The detrital components in XIF correlate with High Field Strength Elements (HFSE) suggesting increased delivery of siliciclastic material during deposition. This trend is comparable to other NIF deposits suggesting a global high input of siliciclastic material into Neoproterozoic paleodepositional environments. This trend is different from Archean and Paleoproterozoic BIF deposits which are close to pure chemical sediments lacking measurable detrital contributions. In the XIF, bulk-rock Mn3O4 and Al2O3 in drillcore SW have higher averages of 2.4 and 2.6 wt. % respectively, compared to the other three cores. The Mn3O4 shows a positive statistical relationship with Co, suggesting that Neoproterozoic oceans and atmosphere were possibly more oxic than in the Archean and Paleoproterozoic. The Mn3O4 shows an antithetic relationship with Fe2O3 suggesting that the paleobasin was chemically heterogeneous in terms of redox conditions, with Fe2O3 depositing presumably in deeper parts removed from a detrital source, and Mn3O4 depositing possibly more proximal to a paleo-shoreline in a shallower setting where there was higher delivery of siliciclastic material from the continent due to correspondingly higher Al2O3 and TiO2 contents. The REE patterns of XIF show positive-sloping trends of depletion in LREE and enrichment in HREE which resemble those of seawater. However, the REE slope becomes a lot flatter and resembles closer the signature of PAAS and adjacent diamictite facies, which agrees with the idea of high siliciclastic input in the paleobasin comparable to other NIF. XIF also appears to lack clear Ce or Eu anomalies. The lack of the former points to the oceans possibly not being oxic enough to drive the fractionation of Ce into Mn oxides like in the modern oceans, or that the Ce behaviour is obscured by the high siliciclastic input in XIF. Similarly, the lack of positive Eu anomaly shows a weak to absent hydrothermal signal into to modern shallow seawater where Fe and Si were sourced, or detritally derived REE contamination. Extensive weathering under hot and humid climate during glacial retreat is shown by the low K2O/Al2O3 ratios and high CIA values ranging from 80-99. Re-glaciation signifies the return of cold and arid and it is represented by high K2O/Al2O3 ratios and low CIA values ranging from 64-78. The previous genetic models of NIF by Klein (1993), Baldwin et al. (2012) and Lechte and Wallace (2015) provide an essential foundation for the development of a XIF genetic model. The genetic model of XIF proposes deposition on an open continental shelf characterized by a steady influx of detrital material. The seawater has been anoxic since the Paleoproterozoic and further induced by basin stagnation due to the ice covering the basin. Two overlapping oxidative stages are assumed for the precipitation of Fe and Mn across lateral redox gradients in the paleobasin. The exact oxidative pathways and mechanisms for the above processes remains unconstrained.
- Full Text:
- Date Issued: 2020
Mobilising the indigenous practice of making Oshikundu using an inquiry-based approach to support Grade 8 Life Science teachers in mediating learning of enzymes
- Shinana, Ester Ndakondja Lineekela
- Authors: Shinana, Ester Ndakondja Lineekela
- Date: 2020
- Subjects: Education, Secondary -- Namibia , Ethnoscience -- Namibia , Fermented beverages -- Namibia , Science -- Study and teaching (Secondary) -- Namibia , Enzymes -- Study and teaching (Secondary) -- Namibia , Ethnoscience -- Study and teaching (Secondary) -- Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/163615 , vital:41061
- Description: The Namibian curriculum encourages Life Science teachers to integrate indigenous knowledge into their science lessons. Additionally, it also encourages teachers to promote scientific inquiry in their science classrooms. However, it is not clear how Life Science teachers should go about doing this. As a result, science is taught in decontextualised ways and inquiry-based methods are neglected. It is against this background that this study sought to mobilise the indigenous practice of making oshikundu to mediate learning of enzymes and to promote inquiry-based methods. Essentially, an attempt was made to mediate the learning of enzymes through inquiry-based methods using, in particular, the Predict-Explain-Explore-Observe-Explain (PEEOE)approach.The approach entails learners making predictions and providing explanations for their predictions before they do their observations. The study employed a qualitative case study approach underpinned by an interpretive paradigm. It was conducted at two schools in the Omusati Region in Namibia and three Life Science teachers (two from one school and one from a different school) participated in this study.A variety of data gathering techniques such as document analysis, workshop discussions, participatory observation, and journal reflections were used to gather data and for triangulation purposes. A thematic approach to data analysis was adopted and data analysis and interpretation we redone inductively using Vygotsky’s socio-cultural theory and Shulman’s Pedagogical Content Kno Knowledge (TSPCK) model was used as the analytical framework to identify and improve the quality of Life Science teachers’ PCK in the topic of enzyme s in particular. Findings from this study revealed that some teachers had a narrow understanding of the concept of scientific inquiry, whereas some demonstrated a better understanding of the concept and how it is used in Life Science classrooms. The findings also revealed that the understanding of the teachers of an inquiry approach and how they understood science should be taught, further influenced their practice ; this was in addition to resource constraints. Furthermore, it was also established that some teachers did not include the concept of enzymes in their teaching. The workshop intervention equipped teachers with the knowledge on an inquiry approach and how to promote scientific inquiry skills in their classrooms. Likewise, the practical demonstration of making oshikundu also equipped the teachers with the knowledge of enzymes and together with the PEEOE approach, how to teach enzyme s using an inquiry approach. Teachers experienced challenges, as they had to use their creative, critical thinking and reasoning skills in order to identify the scientific concepts from the practical demonstration of oshikundu. The study suggests that there is a need for professional development programmes focusing specifically on supporting in-service science teachers’ understanding of inquiry and how to use the inquiry-based approach in their classrooms. Equally, the pre-service science teachers need such preparations during their training. Furthermore, the study also presents that there is a need to engage both pre-service and in-service teachers deeply with the new content of the Life Science syllabus.
- Full Text:
- Date Issued: 2020
- Authors: Shinana, Ester Ndakondja Lineekela
- Date: 2020
- Subjects: Education, Secondary -- Namibia , Ethnoscience -- Namibia , Fermented beverages -- Namibia , Science -- Study and teaching (Secondary) -- Namibia , Enzymes -- Study and teaching (Secondary) -- Namibia , Ethnoscience -- Study and teaching (Secondary) -- Namibia
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/163615 , vital:41061
- Description: The Namibian curriculum encourages Life Science teachers to integrate indigenous knowledge into their science lessons. Additionally, it also encourages teachers to promote scientific inquiry in their science classrooms. However, it is not clear how Life Science teachers should go about doing this. As a result, science is taught in decontextualised ways and inquiry-based methods are neglected. It is against this background that this study sought to mobilise the indigenous practice of making oshikundu to mediate learning of enzymes and to promote inquiry-based methods. Essentially, an attempt was made to mediate the learning of enzymes through inquiry-based methods using, in particular, the Predict-Explain-Explore-Observe-Explain (PEEOE)approach.The approach entails learners making predictions and providing explanations for their predictions before they do their observations. The study employed a qualitative case study approach underpinned by an interpretive paradigm. It was conducted at two schools in the Omusati Region in Namibia and three Life Science teachers (two from one school and one from a different school) participated in this study.A variety of data gathering techniques such as document analysis, workshop discussions, participatory observation, and journal reflections were used to gather data and for triangulation purposes. A thematic approach to data analysis was adopted and data analysis and interpretation we redone inductively using Vygotsky’s socio-cultural theory and Shulman’s Pedagogical Content Kno Knowledge (TSPCK) model was used as the analytical framework to identify and improve the quality of Life Science teachers’ PCK in the topic of enzyme s in particular. Findings from this study revealed that some teachers had a narrow understanding of the concept of scientific inquiry, whereas some demonstrated a better understanding of the concept and how it is used in Life Science classrooms. The findings also revealed that the understanding of the teachers of an inquiry approach and how they understood science should be taught, further influenced their practice ; this was in addition to resource constraints. Furthermore, it was also established that some teachers did not include the concept of enzymes in their teaching. The workshop intervention equipped teachers with the knowledge on an inquiry approach and how to promote scientific inquiry skills in their classrooms. Likewise, the practical demonstration of making oshikundu also equipped the teachers with the knowledge of enzymes and together with the PEEOE approach, how to teach enzyme s using an inquiry approach. Teachers experienced challenges, as they had to use their creative, critical thinking and reasoning skills in order to identify the scientific concepts from the practical demonstration of oshikundu. The study suggests that there is a need for professional development programmes focusing specifically on supporting in-service science teachers’ understanding of inquiry and how to use the inquiry-based approach in their classrooms. Equally, the pre-service science teachers need such preparations during their training. Furthermore, the study also presents that there is a need to engage both pre-service and in-service teachers deeply with the new content of the Life Science syllabus.
- Full Text:
- Date Issued: 2020
Molecular simulations of potential agents and targets of Alzheimer’s disease
- Authors: Carlisle, Tanya
- Date: 2020
- Subjects: Alzheimer's disease -- Treatment , Alzheimer's disease -- Molecular aspects , Amyloid beta-protein precurs , Amyloid beta-protein
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/140025 , vital:37825
- Description: The World Alzheimer Report statedin 2016 that approximately 46.8 million people were living with dementia and this figure is expected to triple by 2050. Alzheimer’s Disease was discovered to be a precursor to dementia in 1976 and since then efforts to understand Alzheimer’s have been prioritized. To date, there are very few effective forms of treatment for Alzheimer’s, many are known to offer only mild calming of the symptoms and have side effects such as diarrhea, nausea, loss of appetite and sleep disturbances. This has been due to lack of understanding on how Alzheimer’s is caused. With the two main hallmarks of the disease now being more understood it has opened the doorway into the discovery of new treatments for this disease. This study focuses on the hallmark involving the aggregation of the β-amyloid protein to form plaques surrounding the neurons of the brain. Copper, Zinc and Iron have also been found in high concentrations in and surrounding these plaques. This study focused on the screening of the South African Natural Compound database (SANCDB) to discover hits that have potential destabilizing action against the Beta-amyloid aggregate. If one of these compounds could prove to have destabilizing action on the aggregate it could open the doorway to new potential forms of treatment. Over 700 SANCDB compounds were docked, and the top hits were taken to molecular dynamics to further study the interactions of the compounds and the aggregate. However, the hits identified had strong binding to the aggregate causing it to become stable instead of the desired effect of destabilizing the structure. This information, however, does not rule out the possibility of these compounds preventing the formation of the aggregates. Further, interactions of copper with β-amyloid and copper were determined by solubilizing the aggregate and introducing copper ions in a dynamics simulation. Possible interactions between copper and the methionine residues were visualised.
- Full Text:
- Date Issued: 2020
- Authors: Carlisle, Tanya
- Date: 2020
- Subjects: Alzheimer's disease -- Treatment , Alzheimer's disease -- Molecular aspects , Amyloid beta-protein precurs , Amyloid beta-protein
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/140025 , vital:37825
- Description: The World Alzheimer Report statedin 2016 that approximately 46.8 million people were living with dementia and this figure is expected to triple by 2050. Alzheimer’s Disease was discovered to be a precursor to dementia in 1976 and since then efforts to understand Alzheimer’s have been prioritized. To date, there are very few effective forms of treatment for Alzheimer’s, many are known to offer only mild calming of the symptoms and have side effects such as diarrhea, nausea, loss of appetite and sleep disturbances. This has been due to lack of understanding on how Alzheimer’s is caused. With the two main hallmarks of the disease now being more understood it has opened the doorway into the discovery of new treatments for this disease. This study focuses on the hallmark involving the aggregation of the β-amyloid protein to form plaques surrounding the neurons of the brain. Copper, Zinc and Iron have also been found in high concentrations in and surrounding these plaques. This study focused on the screening of the South African Natural Compound database (SANCDB) to discover hits that have potential destabilizing action against the Beta-amyloid aggregate. If one of these compounds could prove to have destabilizing action on the aggregate it could open the doorway to new potential forms of treatment. Over 700 SANCDB compounds were docked, and the top hits were taken to molecular dynamics to further study the interactions of the compounds and the aggregate. However, the hits identified had strong binding to the aggregate causing it to become stable instead of the desired effect of destabilizing the structure. This information, however, does not rule out the possibility of these compounds preventing the formation of the aggregates. Further, interactions of copper with β-amyloid and copper were determined by solubilizing the aggregate and introducing copper ions in a dynamics simulation. Possible interactions between copper and the methionine residues were visualised.
- Full Text:
- Date Issued: 2020
Molecular simulations of potential agents and targets of Alzheimer’s disease
- Authors: Joli, Luxolo
- Date: 2020
- Subjects: Alzheimer's disease -- Chemotherapy , Alzheimer's disease -- Treatment , Ligands (Biochemistry) , Proteins -- Chemistry , Molecular dynamics -- Simulation methods
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/146411 , vital:38523
- Description: Alzheimer's Disease (AD) is a neurodegenerative brain disorder that was first discovered in 1901 by Dr Aloïs Alzheimer and was later reported publicly in 1906. The German doctor had a 51-yearold woman patient called Auguste Deter, who was suffering from a rare brain disorder with early signs of memory loss and cognition. Alzheimer's Disease is the most common type of dementia that affects people with the age of 65 years and older. There is no single known cause of Alzheimer’s disease however, amyloid β-peptide (Aβ1–40/42) was found to be at the centre of AD pathogenesis and this connection was referred as “amyloid hypothesis”. It is suspected that an accumulation of amyloid β-peptide is a major contributor to neuronal dysfunction and degeneration. Alzheimer’s disease is complex and therefore, currently there is no medication available that treats the disease. However, there are approaches that focus on helping people maintain mental function, manage behavioral symptoms, and slow down the symptoms of disease. According to South Africa’s 2011 census, there are approximately 2.2 million people in South Africa with some form of dementia and therefore there is a need to find a treatment for the disease. This study aims to find agents and targets of Alzheimer’s Disease by using different computational techniques such as molecular modelling. The study will use compounds from the South African Compounds Database (SANCDB) and the following therapeutic targets α-, β- and γ-secretase, acetylcholinesterase, tau protein and neprilysin. A successful High-throughput Virtual Screening (HTVS) study to determine lead compounds was performed using a computational program called KNIME. Molecular docking was achieved with GLIDE as it allows for exhaustive ligand flexibility. The docking calculations were carried out using the high level of precision XP (extra precision) for enhanced docking accuracy. The binding affinities (docking scores) for the best bound ligands obtained from docking were in the order of -5 kcal/mol or less. The ligandSANC00370 was the best binding ligand against the protein 1J1C_B and had the best binding energy of -13.94 kcal/mol compared to others. The receptor-ligand complexes were analyzed using the interaction diagrams obtained from the Discovery Studio Visualizer and Maestro programs. Molecular Dynamics simulations were performed on the complexes obtained from docking to help in optimizing their interactions. The simulations were performed using the Desmond tool with the OPLS3 force field. 100 ns simulations were performed for six systems with the best docking score results epresenting each of the therapeutic targets and for the other complex systems, 50 ns simulations were performed. The Desmond simulations were analyzed using the Simulations Interaction Diagrams such as PL-RMSD, L-RMSF, P-RMSF, L-Torsions, P-SSE, LP-Contacts and L-Properties. Maestro was used to visualize the stability of the ligands in the active site during the simulation. All 13 Desmond simulations were successful however, there were 9 simulations which produced satisfactory results while the others were nsatisfactory. Based on the molecular docking and Molecular Dynamics results of this study, 9 potential targets and 6 potential agents were obtained successfully and can be studied further as therapeutics for Alzheimer’s Disease.
- Full Text:
- Date Issued: 2020
- Authors: Joli, Luxolo
- Date: 2020
- Subjects: Alzheimer's disease -- Chemotherapy , Alzheimer's disease -- Treatment , Ligands (Biochemistry) , Proteins -- Chemistry , Molecular dynamics -- Simulation methods
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/146411 , vital:38523
- Description: Alzheimer's Disease (AD) is a neurodegenerative brain disorder that was first discovered in 1901 by Dr Aloïs Alzheimer and was later reported publicly in 1906. The German doctor had a 51-yearold woman patient called Auguste Deter, who was suffering from a rare brain disorder with early signs of memory loss and cognition. Alzheimer's Disease is the most common type of dementia that affects people with the age of 65 years and older. There is no single known cause of Alzheimer’s disease however, amyloid β-peptide (Aβ1–40/42) was found to be at the centre of AD pathogenesis and this connection was referred as “amyloid hypothesis”. It is suspected that an accumulation of amyloid β-peptide is a major contributor to neuronal dysfunction and degeneration. Alzheimer’s disease is complex and therefore, currently there is no medication available that treats the disease. However, there are approaches that focus on helping people maintain mental function, manage behavioral symptoms, and slow down the symptoms of disease. According to South Africa’s 2011 census, there are approximately 2.2 million people in South Africa with some form of dementia and therefore there is a need to find a treatment for the disease. This study aims to find agents and targets of Alzheimer’s Disease by using different computational techniques such as molecular modelling. The study will use compounds from the South African Compounds Database (SANCDB) and the following therapeutic targets α-, β- and γ-secretase, acetylcholinesterase, tau protein and neprilysin. A successful High-throughput Virtual Screening (HTVS) study to determine lead compounds was performed using a computational program called KNIME. Molecular docking was achieved with GLIDE as it allows for exhaustive ligand flexibility. The docking calculations were carried out using the high level of precision XP (extra precision) for enhanced docking accuracy. The binding affinities (docking scores) for the best bound ligands obtained from docking were in the order of -5 kcal/mol or less. The ligandSANC00370 was the best binding ligand against the protein 1J1C_B and had the best binding energy of -13.94 kcal/mol compared to others. The receptor-ligand complexes were analyzed using the interaction diagrams obtained from the Discovery Studio Visualizer and Maestro programs. Molecular Dynamics simulations were performed on the complexes obtained from docking to help in optimizing their interactions. The simulations were performed using the Desmond tool with the OPLS3 force field. 100 ns simulations were performed for six systems with the best docking score results epresenting each of the therapeutic targets and for the other complex systems, 50 ns simulations were performed. The Desmond simulations were analyzed using the Simulations Interaction Diagrams such as PL-RMSD, L-RMSF, P-RMSF, L-Torsions, P-SSE, LP-Contacts and L-Properties. Maestro was used to visualize the stability of the ligands in the active site during the simulation. All 13 Desmond simulations were successful however, there were 9 simulations which produced satisfactory results while the others were nsatisfactory. Based on the molecular docking and Molecular Dynamics results of this study, 9 potential targets and 6 potential agents were obtained successfully and can be studied further as therapeutics for Alzheimer’s Disease.
- Full Text:
- Date Issued: 2020
Multilingualism, innovation, and productivity: an examination of the impact of multilingualism in the workplace, with reference to the BRICS countries
- Authors: Leyne, Breda
- Date: 2020
- Subjects: Multilingualism -- BRIC countries , Bilingual communication in organizations , Second language acquisition , Language in the workplace , Diversity in the workplace , Communication in organizations , Intercultural communication , Labor productivity , Organizational behavior , Technological innovations , BRICS countries
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/148149 , vital:38714
- Description: This study examined whether the choice of language in the workplace affects personal and workplace productivity. The study has focussed on those working in countries which come under the BRICS grouping, Brazil, Russia, India and China and South Africa, as this provided a rich comparison of historical, economic and linguistic contexts. The research undertaken sought to explore the impact of prevailing language usage amongst employees of multi-national companies operating within the BRICS countries. With the assumption that these workforces will include multilingual individuals, the study set out to ascertain whether multilingualism has been recognised as a factor that might impact upon personal productivity or progress, either in a positive or negative fashion. The study set out to consider how language use may affect economic behaviour, firstly on a personal level and then to extrapolate this more widely into organisational productivity and innovation. This was set against background research into; theoretical perspectives on the acquisition of additional language, perceived benefits of bilingualism for individuals, studies of the management of language use with multinational corporations and relationships between language and economics. The conclusion reached is that multilingualism could have a beneficial impact on wider workforce productivity, and that it is not just a ‘language problem’ as it often seems to be treated. The final conclusion is that this may be something that should be more carefully considered by organisations in an increasingly global workplace. The researcher considers that multilingualism could be better employed as a workplace productivity metric, in a way that arguably it is not at present.
- Full Text:
- Date Issued: 2020
- Authors: Leyne, Breda
- Date: 2020
- Subjects: Multilingualism -- BRIC countries , Bilingual communication in organizations , Second language acquisition , Language in the workplace , Diversity in the workplace , Communication in organizations , Intercultural communication , Labor productivity , Organizational behavior , Technological innovations , BRICS countries
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/148149 , vital:38714
- Description: This study examined whether the choice of language in the workplace affects personal and workplace productivity. The study has focussed on those working in countries which come under the BRICS grouping, Brazil, Russia, India and China and South Africa, as this provided a rich comparison of historical, economic and linguistic contexts. The research undertaken sought to explore the impact of prevailing language usage amongst employees of multi-national companies operating within the BRICS countries. With the assumption that these workforces will include multilingual individuals, the study set out to ascertain whether multilingualism has been recognised as a factor that might impact upon personal productivity or progress, either in a positive or negative fashion. The study set out to consider how language use may affect economic behaviour, firstly on a personal level and then to extrapolate this more widely into organisational productivity and innovation. This was set against background research into; theoretical perspectives on the acquisition of additional language, perceived benefits of bilingualism for individuals, studies of the management of language use with multinational corporations and relationships between language and economics. The conclusion reached is that multilingualism could have a beneficial impact on wider workforce productivity, and that it is not just a ‘language problem’ as it often seems to be treated. The final conclusion is that this may be something that should be more carefully considered by organisations in an increasingly global workplace. The researcher considers that multilingualism could be better employed as a workplace productivity metric, in a way that arguably it is not at present.
- Full Text:
- Date Issued: 2020
My crazy character
- Authors: Sojini, Lungile
- Date: 2020
- Subjects: South African fiction (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/148217 , vital:38720
- Description: My thesis is a metafictional novella. I am interested in fictionalising the processes that writers use when they sit down to plan, write and publish novels. Metafiction interests me because it breaks from the traditional way of writing fiction, particularly with regards to the appearance of the author in the fictional world created. Devin Gribbons’s metafictional story (titled A Short Story), in the anthology of innovative writing, 30 Under 30, was my inspiration for developing the metafictional approach to novella length. Fyodor Dostoevsky’s Notes from Underground, Chief Fagunwa’s Forest of a Thousand Daemons, and Charles Bukowski’s autobiographical Ham on Rye, have for varying reasons, all influenced this writing.
- Full Text:
- Date Issued: 2020
- Authors: Sojini, Lungile
- Date: 2020
- Subjects: South African fiction (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/148217 , vital:38720
- Description: My thesis is a metafictional novella. I am interested in fictionalising the processes that writers use when they sit down to plan, write and publish novels. Metafiction interests me because it breaks from the traditional way of writing fiction, particularly with regards to the appearance of the author in the fictional world created. Devin Gribbons’s metafictional story (titled A Short Story), in the anthology of innovative writing, 30 Under 30, was my inspiration for developing the metafictional approach to novella length. Fyodor Dostoevsky’s Notes from Underground, Chief Fagunwa’s Forest of a Thousand Daemons, and Charles Bukowski’s autobiographical Ham on Rye, have for varying reasons, all influenced this writing.
- Full Text:
- Date Issued: 2020
Nine stories
- Authors: Dukas, Graham
- Date: 2020
- Subjects: South African fiction (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/147124 , vital:38595
- Description: Creative work portfolio.
- Full Text:
- Date Issued: 2020
- Authors: Dukas, Graham
- Date: 2020
- Subjects: South African fiction (English) -- 21st century
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/147124 , vital:38595
- Description: Creative work portfolio.
- Full Text:
- Date Issued: 2020
Now that we have the land: analysing the experiences of land reform beneficiaries in the Makana Municipal District of the Eastern Cape, South Africa
- Authors: Msuthu, Simela Thuleka
- Date: 2020
- Subjects: Land reform , Sustainable development , Land reform -- South Africa -- Eastern Cape , Land tenure -- South Africa -- Eastern Cape , Land settlement -- Government policy -- South Africa -- Eastern Cape , Restitution -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Municipal government -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/167551 , vital:41491
- Description: The “land question” in South Africa goes back more than a century to the 1913 Natives Land Act which facilitated the dispossession of African people from fertile land to arid homelands and congested townships. This mass dispossession of Africans from their land was accompanied by an array of legislation aimed at restricting their upward mobility, thus laying the foundations of structural inequality in South Africa. The advent of democracy in 1994 brought about a number of legislative reforms aimed at addressing the injustices that were imposed by the colonial and apartheid governments on the African people. At the forefront of these legislative efforts was the restoration of land to the original inhabitants of the country. Research indicates that, since 1994, the South African government has issued out land to different individuals and communities around the country in an attempt to address structural unemployment and poverty that plague the country. Using the Sustainable Livelihoods Theoretical framework, this study sought to examine the experiences of land reform beneficiaries in the Makana Municipal district of the Eastern Cape, in order to determine the extent to which the transfer of land to landless people has met the governments’ agenda to alleviate poverty and unemployment in the rural regions of South Africa. The findings in this study show that, successful land reform in South Africa is hindered mostly by two factors. Firstly, the inability of land beneficiaries to access quality education, skills training, finances and formal agricultural value chains. Secondly, land beneficiaries are further placed at a disadvantage by the poor quality of public services in their local municipalities and inconsistent post-settlement support from the state. The conclusion made in this study, is that the government has to be cognizant of the aforementioned structural barriers, when designing and rolling out land reform projects throughout the country. Failure to address these glaring structural barriers, will result in the creation of a peasant class of people living on underutilized land.
- Full Text:
- Date Issued: 2020
- Authors: Msuthu, Simela Thuleka
- Date: 2020
- Subjects: Land reform , Sustainable development , Land reform -- South Africa -- Eastern Cape , Land tenure -- South Africa -- Eastern Cape , Land settlement -- Government policy -- South Africa -- Eastern Cape , Restitution -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Municipal government -- South Africa -- Eastern Cape , Rural development -- South Africa -- Eastern Cape
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/167551 , vital:41491
- Description: The “land question” in South Africa goes back more than a century to the 1913 Natives Land Act which facilitated the dispossession of African people from fertile land to arid homelands and congested townships. This mass dispossession of Africans from their land was accompanied by an array of legislation aimed at restricting their upward mobility, thus laying the foundations of structural inequality in South Africa. The advent of democracy in 1994 brought about a number of legislative reforms aimed at addressing the injustices that were imposed by the colonial and apartheid governments on the African people. At the forefront of these legislative efforts was the restoration of land to the original inhabitants of the country. Research indicates that, since 1994, the South African government has issued out land to different individuals and communities around the country in an attempt to address structural unemployment and poverty that plague the country. Using the Sustainable Livelihoods Theoretical framework, this study sought to examine the experiences of land reform beneficiaries in the Makana Municipal district of the Eastern Cape, in order to determine the extent to which the transfer of land to landless people has met the governments’ agenda to alleviate poverty and unemployment in the rural regions of South Africa. The findings in this study show that, successful land reform in South Africa is hindered mostly by two factors. Firstly, the inability of land beneficiaries to access quality education, skills training, finances and formal agricultural value chains. Secondly, land beneficiaries are further placed at a disadvantage by the poor quality of public services in their local municipalities and inconsistent post-settlement support from the state. The conclusion made in this study, is that the government has to be cognizant of the aforementioned structural barriers, when designing and rolling out land reform projects throughout the country. Failure to address these glaring structural barriers, will result in the creation of a peasant class of people living on underutilized land.
- Full Text:
- Date Issued: 2020
Nutrient removal and biofuel potential of MaB-floc biomass from an integrated algal pond system treating domestic sewage
- Authors: Sibelo, Linda
- Date: 2020
- Subjects: Biomass energy , Waste products as fuel , Algal biofuels , Sewage -- Purification -- Nutrient removal
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/144955 , vital:38395
- Description: Integrated algal pond systems (IAPS) are a passive water treatment technology derived from the Oswald designed advanced integrated wastewater pond systems (AIWPS®) and effect wastewater treatment based on biological activity of microorganisms within the system, solar energy and gravity. The technology consists of an advanced facultative pond (AFP), a series of interconnected high rate algal oxidation ponds (HRAOP) and algal settling ponds. The symbiotic relationship between microalgae and bacteria facilitated by paddlewheel mixing of HRAOP results in the formation of biomass aggregates known as MaB-flocs. MaB-floc formation enhances nutrient abstraction, gravitational sedimentation and separation from water hence forming two product streams; recyclable water and biomass, both with valorisation potential. This work aimed to determine the suitability of MaB-floc biomass generated in the HRAOP of an IAPS treating domestic sewage as feedstock for biofuel production based on the content of carbohydrate and lipid. Nutrient removal efficiency, biomass productivity and bulk lipid and carbohydrate concentration were monitored for two consecutive three-month periods in the winter and summer seasons of 2018/19. Maximum removal efficiencies of nitrogen and phosphorus were determined as 71% and 75% respectively, demonstrating the efficiency of IAPS as a wastewater treatment technology. MaB-floc biomass productivity in winter and summer was 9.4 g/m2/d and 16.5 g/m2/d respectively indicating the heavy influence of seasonal temperature, possibly day length, and solar irradiation on biomass productivity in the HRAOP. Summer productivity was lower than the maximum theoretical productivity of 25 g/m2/d possibly due to photoinhibition of photosynthesis as well as grazing pressures caused by the proliferation of rotifers mainly of the Brachionus genus. MaB-floc biomass consistently contained higher amounts of carbohydrate than lipid despite the changes in species dominance from Scenedesmus sp. and Desmodesmus sp. in winter to Pediastrum sp. in summer. Variations in MaB-floc biomass carbohydrate content were linked to changes in nitrogen concentration, mainly in the form of nitrates. Lower nitrogen concentration significantly increased the carbohydrate content of MaB-floc biomass from 17.5 ± 0.15% to 33.5 ± 0.3 % recorded in summer. In winter, biomass carbohydrate increased from 18.3 ± 1.2% to 35.8 ± 0.3%.To induce accumulation of carbohydrates through nitrogen starvation, isolated microalgal species native to the HRAOPs of the IAPS at Institute for Environmental Biotechnology Rhodes University(EBRU) were used. The outcome from the laboratory studies showed that carbon partitioning within isolated strains could be altered from carbohydrate to lipid which is more energy-rich. Hence, exploring the biodiesel production option using HRAOP MaB-floc biomass, which had a lipid content ranging between 12.1 ± 0.64 % and 13.9 ± 0.5 %, would require a preconditioning step in the form of nitrogen starvation to enhance its lipid content. Overall, the outcome of outdoor monitoring studies on biomass biochemical composition indicated that HRAOPs operating under natural environmental conditions preferentially generated a biomass rich in carbohydrate. Therefore, anaerobic digestion may be a more viable option for HRAOP MaB-floc biomass because of the high carbohydrate levels ranging between 24.9 ± 0.6 % and 25.6 ± 1.3 % of the dry MaB-floc biomass weight. Despite the low biomass C/N ratio (7.1 to 7.8), the MaB-floc biomass can be anaerobically co-digested with a higher C/N ratio (24) substrate such as in-pond digester sludge, to improve methane yields calculated to be between 0.31 m3 CH4/ kg MaB-floc biomass and 0.33 m3 CH4/ kg MaB-floc biomass. Anaerobic digestion of biomass also produces CO2 which can be recovered and added to HRAOPs to enhance MaB-floc biomass productivity while lowering greenhouse gas emissions from a wastewater treatment plant. The digestate from the anaerobic process, which is rich in nitrogen and phosphorus can be used as a biofertiliser. Thus, a potential MaB-floc biomass biorefinery consisting of biogas and bio-fertiliser pathways can be established using IAPS treating sewage as the platform technology. IAPS is a system designed to operate in a way that is passive and without substantial environmental impact but technological innovations and a reduction in the size of the system are required to make the technology more acceptable.
- Full Text:
- Date Issued: 2020
- Authors: Sibelo, Linda
- Date: 2020
- Subjects: Biomass energy , Waste products as fuel , Algal biofuels , Sewage -- Purification -- Nutrient removal
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/144955 , vital:38395
- Description: Integrated algal pond systems (IAPS) are a passive water treatment technology derived from the Oswald designed advanced integrated wastewater pond systems (AIWPS®) and effect wastewater treatment based on biological activity of microorganisms within the system, solar energy and gravity. The technology consists of an advanced facultative pond (AFP), a series of interconnected high rate algal oxidation ponds (HRAOP) and algal settling ponds. The symbiotic relationship between microalgae and bacteria facilitated by paddlewheel mixing of HRAOP results in the formation of biomass aggregates known as MaB-flocs. MaB-floc formation enhances nutrient abstraction, gravitational sedimentation and separation from water hence forming two product streams; recyclable water and biomass, both with valorisation potential. This work aimed to determine the suitability of MaB-floc biomass generated in the HRAOP of an IAPS treating domestic sewage as feedstock for biofuel production based on the content of carbohydrate and lipid. Nutrient removal efficiency, biomass productivity and bulk lipid and carbohydrate concentration were monitored for two consecutive three-month periods in the winter and summer seasons of 2018/19. Maximum removal efficiencies of nitrogen and phosphorus were determined as 71% and 75% respectively, demonstrating the efficiency of IAPS as a wastewater treatment technology. MaB-floc biomass productivity in winter and summer was 9.4 g/m2/d and 16.5 g/m2/d respectively indicating the heavy influence of seasonal temperature, possibly day length, and solar irradiation on biomass productivity in the HRAOP. Summer productivity was lower than the maximum theoretical productivity of 25 g/m2/d possibly due to photoinhibition of photosynthesis as well as grazing pressures caused by the proliferation of rotifers mainly of the Brachionus genus. MaB-floc biomass consistently contained higher amounts of carbohydrate than lipid despite the changes in species dominance from Scenedesmus sp. and Desmodesmus sp. in winter to Pediastrum sp. in summer. Variations in MaB-floc biomass carbohydrate content were linked to changes in nitrogen concentration, mainly in the form of nitrates. Lower nitrogen concentration significantly increased the carbohydrate content of MaB-floc biomass from 17.5 ± 0.15% to 33.5 ± 0.3 % recorded in summer. In winter, biomass carbohydrate increased from 18.3 ± 1.2% to 35.8 ± 0.3%.To induce accumulation of carbohydrates through nitrogen starvation, isolated microalgal species native to the HRAOPs of the IAPS at Institute for Environmental Biotechnology Rhodes University(EBRU) were used. The outcome from the laboratory studies showed that carbon partitioning within isolated strains could be altered from carbohydrate to lipid which is more energy-rich. Hence, exploring the biodiesel production option using HRAOP MaB-floc biomass, which had a lipid content ranging between 12.1 ± 0.64 % and 13.9 ± 0.5 %, would require a preconditioning step in the form of nitrogen starvation to enhance its lipid content. Overall, the outcome of outdoor monitoring studies on biomass biochemical composition indicated that HRAOPs operating under natural environmental conditions preferentially generated a biomass rich in carbohydrate. Therefore, anaerobic digestion may be a more viable option for HRAOP MaB-floc biomass because of the high carbohydrate levels ranging between 24.9 ± 0.6 % and 25.6 ± 1.3 % of the dry MaB-floc biomass weight. Despite the low biomass C/N ratio (7.1 to 7.8), the MaB-floc biomass can be anaerobically co-digested with a higher C/N ratio (24) substrate such as in-pond digester sludge, to improve methane yields calculated to be between 0.31 m3 CH4/ kg MaB-floc biomass and 0.33 m3 CH4/ kg MaB-floc biomass. Anaerobic digestion of biomass also produces CO2 which can be recovered and added to HRAOPs to enhance MaB-floc biomass productivity while lowering greenhouse gas emissions from a wastewater treatment plant. The digestate from the anaerobic process, which is rich in nitrogen and phosphorus can be used as a biofertiliser. Thus, a potential MaB-floc biomass biorefinery consisting of biogas and bio-fertiliser pathways can be established using IAPS treating sewage as the platform technology. IAPS is a system designed to operate in a way that is passive and without substantial environmental impact but technological innovations and a reduction in the size of the system are required to make the technology more acceptable.
- Full Text:
- Date Issued: 2020
Observations of diffuse radio emission in the Abell 773 galaxy cluster
- Authors: Sichone, Gift L
- Date: 2020
- Subjects: Galaxies -- Clusters -- Observations , Radio astronomy -- Observations , Astrophysics -- South Africa , Westerbork Radio Telescope , A773 galaxy cluster , Astronomy -- Observations , Radio sources (Astronomy
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/144945 , vital:38394
- Description: In this thesis, we present 18 and 21 cm observations of the A773 galaxy cluster observed with the Westerbork radio telescope. The final 18 and 21 cm images achieve a noise level of 0.018 mJy beam‾ 1 and 0.025 mJy beam-1 respectively. After subtracting the compact sources, the low resolution images show evidence of a radio halo at 18 cm, whereas its presence is more uncertain in the low resolution 21 cm images due the presence of residual sidelobes from bright sources. In the joint analysis of both frequencies, the radio halo has a 5.37 arcmin2 area with a 6.76 mJy flux density. Further observations and analysis are, however, required to fully characterize its properties.
- Full Text:
- Date Issued: 2020
- Authors: Sichone, Gift L
- Date: 2020
- Subjects: Galaxies -- Clusters -- Observations , Radio astronomy -- Observations , Astrophysics -- South Africa , Westerbork Radio Telescope , A773 galaxy cluster , Astronomy -- Observations , Radio sources (Astronomy
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/144945 , vital:38394
- Description: In this thesis, we present 18 and 21 cm observations of the A773 galaxy cluster observed with the Westerbork radio telescope. The final 18 and 21 cm images achieve a noise level of 0.018 mJy beam‾ 1 and 0.025 mJy beam-1 respectively. After subtracting the compact sources, the low resolution images show evidence of a radio halo at 18 cm, whereas its presence is more uncertain in the low resolution 21 cm images due the presence of residual sidelobes from bright sources. In the joint analysis of both frequencies, the radio halo has a 5.37 arcmin2 area with a 6.76 mJy flux density. Further observations and analysis are, however, required to fully characterize its properties.
- Full Text:
- Date Issued: 2020
Observations of diffuse radio emission in the Perseus Galaxy Cluster
- Authors: Mungwariri, Clemence
- Date: 2020
- Subjects: Galaxies -- Clusters , Radio sources (Astronomy) , Radio interferometers , Perseus Galaxy Cluster , Diffuse radio emission
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/143325 , vital:38233
- Description: In this thesis we analysed Westerbork observations of the Perseus Galaxy Cluster at 1380 MHz. Observations consist of two different pointings, covering a total of ∼ 0.5 square degrees, one including the known mini halo and the source 3C 84, the other centred on the source 3C 83.1 B. We obtained images with 83 μJy beam⁻¹ and 240 μJy beam⁻¹ noise rms for the two pointings respectively. We achieved a 60000 : 1 dynamic range in the image containing the bright 3C 84 source. We imaged the mini halo surrounding 3C 84 at high sensitivity, measuring its diameter to be ∼140 kpc and its power 4 x 10²⁴ W Hz⁻¹. Its morphology agrees quite well with that observed at 240 MHz (e.g. Gendron-Marsolais et al., 2017). We measured the flux density of 3C 84 to be 20.5 ± 0.4 Jy at the 2007 epoch, consistent with a factor of ∼2 increase since the 1960s.
- Full Text:
- Date Issued: 2020
- Authors: Mungwariri, Clemence
- Date: 2020
- Subjects: Galaxies -- Clusters , Radio sources (Astronomy) , Radio interferometers , Perseus Galaxy Cluster , Diffuse radio emission
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/143325 , vital:38233
- Description: In this thesis we analysed Westerbork observations of the Perseus Galaxy Cluster at 1380 MHz. Observations consist of two different pointings, covering a total of ∼ 0.5 square degrees, one including the known mini halo and the source 3C 84, the other centred on the source 3C 83.1 B. We obtained images with 83 μJy beam⁻¹ and 240 μJy beam⁻¹ noise rms for the two pointings respectively. We achieved a 60000 : 1 dynamic range in the image containing the bright 3C 84 source. We imaged the mini halo surrounding 3C 84 at high sensitivity, measuring its diameter to be ∼140 kpc and its power 4 x 10²⁴ W Hz⁻¹. Its morphology agrees quite well with that observed at 240 MHz (e.g. Gendron-Marsolais et al., 2017). We measured the flux density of 3C 84 to be 20.5 ± 0.4 Jy at the 2007 epoch, consistent with a factor of ∼2 increase since the 1960s.
- Full Text:
- Date Issued: 2020
Perceptions of the sugar-sweetened beverage tax in South Africa: a comparative study
- Jankeeparsad, Thanesha Reddy
- Authors: Jankeeparsad, Thanesha Reddy
- Date: 2020
- Subjects: Soft drinks -- Taxation -- South Africa , Carbonated drinks -- Taxation -- South Africa , Soft drinks -- Health aspects , College students -- South Africa -- Attitudes
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/142324 , vital:38070
- Description: This exploratory, comparative study aimed to investigate perceptions of the participants in the study in South Africa regarding the tax on sugar-sweetened beverages. The study further aimed to compare these perceptions with perceptions identified in selected foreign jurisdictions that have levied the tax on sugar-sweetened beverages. A voluntary, paper-based, anonymous survey questionnaire that included both closed- and open-ended questions was selected as the primary method of data collection. This questionnaire was administered to post-graduate Bachelor of Commerce Accounting and Postgraduate Diploma in Accounting students, aged twenty-one years and older, studying at three residential universities in South Africa, during the 2018 academic year. An extensive analysis of literature available on sugar-sweetened beverage taxes, both locally and internationally, was conducted. The two main constructs (construct 1: perception of the sugar-sweetened beverage tax and the price of sugar-sweetened beverages and construct 2: the social impact of the sugarsweetened beverage tax) were then analysed using descriptive statistics. This study found that there is a significant association between gender and perception that the sugary beverage levy will be beneficial to health, with female perceptions of the benefit of the sugary beverage levy being greater than that of males. Respondents appear to have a positive perception of the sugary beverages levy, understand the sugary beverage levy, as well as the health benefits that will be derived from the levy. Respondents supported the tax on sugar-sweetened beverages if the revenue generated was used to improve the health care system and if the price of healthy foods decreased. Female respondents were found to drink fewer sugarsweetened beverages than male respondents, but females reported higher sugar-sweetened beverage consumption during stressful periods. The current study can possibly provide policy makers with more information regarding acceptance of the sugar-sweetened beverage tax and shape guidelines for future amendments of the tax imposed.
- Full Text:
- Date Issued: 2020
- Authors: Jankeeparsad, Thanesha Reddy
- Date: 2020
- Subjects: Soft drinks -- Taxation -- South Africa , Carbonated drinks -- Taxation -- South Africa , Soft drinks -- Health aspects , College students -- South Africa -- Attitudes
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/142324 , vital:38070
- Description: This exploratory, comparative study aimed to investigate perceptions of the participants in the study in South Africa regarding the tax on sugar-sweetened beverages. The study further aimed to compare these perceptions with perceptions identified in selected foreign jurisdictions that have levied the tax on sugar-sweetened beverages. A voluntary, paper-based, anonymous survey questionnaire that included both closed- and open-ended questions was selected as the primary method of data collection. This questionnaire was administered to post-graduate Bachelor of Commerce Accounting and Postgraduate Diploma in Accounting students, aged twenty-one years and older, studying at three residential universities in South Africa, during the 2018 academic year. An extensive analysis of literature available on sugar-sweetened beverage taxes, both locally and internationally, was conducted. The two main constructs (construct 1: perception of the sugar-sweetened beverage tax and the price of sugar-sweetened beverages and construct 2: the social impact of the sugarsweetened beverage tax) were then analysed using descriptive statistics. This study found that there is a significant association between gender and perception that the sugary beverage levy will be beneficial to health, with female perceptions of the benefit of the sugary beverage levy being greater than that of males. Respondents appear to have a positive perception of the sugary beverages levy, understand the sugary beverage levy, as well as the health benefits that will be derived from the levy. Respondents supported the tax on sugar-sweetened beverages if the revenue generated was used to improve the health care system and if the price of healthy foods decreased. Female respondents were found to drink fewer sugarsweetened beverages than male respondents, but females reported higher sugar-sweetened beverage consumption during stressful periods. The current study can possibly provide policy makers with more information regarding acceptance of the sugar-sweetened beverage tax and shape guidelines for future amendments of the tax imposed.
- Full Text:
- Date Issued: 2020
Performance of an integrated algal pond for treatment of domestic sewage: a process audit
- Authors: Dube, Anele
- Date: 2020
- Subjects: Water -- Purification , Sewage -- Purification -- Anaerobic treatment , Algae -- Biotechnology , Waste disposal -- South Africa , Integrated algae pond systems (IAPS)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167043 , vital:41432
- Description: Integrated algae pond systems (IAPS) are energy efficient, robust, passive systems that use the principles of fermentation, photosynthesis and microbial metabolism to remediate wastewater, producing a good quality effluent with reuse potential. In addition to the treatment of wastewater, IAPS have the ability to generate two additional product streams viz. biogas and biomass. The latter adds to the attractiveness of the system. However, the implementation of this technology, like many passive systems, has remained limited at a commercial scale, and the inclination is still towards grey technologies. The aim of this research was to investigate the capabilities and potential of a demonstration-scale IAPS and use results obtained to establish a process audit framework. The aspects considered for the audit included performance efficiency, effluent water quality, biomass composition, quantity and productivity within the ponds, and cost analysis of operation and maintenance over a 9-year period. Plant performance was closely monitored during the course of the study and this led to a review of previously adopted plant management strategies. Troubleshooting exercises were also carried out when plant performance declined. Results showed that IAPS efficiently reduced standard water parameters with the exception of pH, dissolved oxygen, and nitrate whose values increased from raw influent to final effluent. The following water quality parameters were established for the final effluent: total suspended solids 55 ± 7.1 mg. L-1 (n = 28); chemical oxygen demand 94.1 ± 10.6 mg. L-1 (n = 28) (after removal of algae); pH 9.9 ± 0.01 (n = 26); ammonium nitrogen 1.7 ± 0.3 mg. L-1 (n = 25); nitrate 3.3 ± 0.6 mg. L-1 (n = 25); ortho-phosphate 1.6 ± 0.2 mg. L-1 (n = 25); electrical conductivity 98.7 ± 2.0 mS m-1 (n = 26) and faecal coliforms (per 100 mL) 1482.6 ± 636.0 (n = 24). The final effluent measured consistently high chemical oxygen demand and total suspended solids, however close analysis showed that total suspended solids could be controlled by increasing the frequency of removal of settled biomass within the settling ponds. Biomass produced contained microalgae, bacteria, metazoa, and protozoa. The biomass productivity achieved was as high as 130.6 kg ha-1 d-1; however, about 33% was lost to the final effluent due to inadequate settling. Results obtained during the course of this study and outcomes of earlier work on IAPS are taken as the baseline to determine parameters needed for the development of the process audit framework. Techniques utilised to derive the blue print process audit protocol for IAPS included a turtle diagram, a flow diagram and a checklist. Attention to plant management proved vital in determining overall performance. Cost, including operating and maintenance, of treating water using the demonstration scale system on a per person equivalent per year basis was determined as ZAR 123.87 (where, ZAR to USD = 0.07).
- Full Text:
- Date Issued: 2020
- Authors: Dube, Anele
- Date: 2020
- Subjects: Water -- Purification , Sewage -- Purification -- Anaerobic treatment , Algae -- Biotechnology , Waste disposal -- South Africa , Integrated algae pond systems (IAPS)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167043 , vital:41432
- Description: Integrated algae pond systems (IAPS) are energy efficient, robust, passive systems that use the principles of fermentation, photosynthesis and microbial metabolism to remediate wastewater, producing a good quality effluent with reuse potential. In addition to the treatment of wastewater, IAPS have the ability to generate two additional product streams viz. biogas and biomass. The latter adds to the attractiveness of the system. However, the implementation of this technology, like many passive systems, has remained limited at a commercial scale, and the inclination is still towards grey technologies. The aim of this research was to investigate the capabilities and potential of a demonstration-scale IAPS and use results obtained to establish a process audit framework. The aspects considered for the audit included performance efficiency, effluent water quality, biomass composition, quantity and productivity within the ponds, and cost analysis of operation and maintenance over a 9-year period. Plant performance was closely monitored during the course of the study and this led to a review of previously adopted plant management strategies. Troubleshooting exercises were also carried out when plant performance declined. Results showed that IAPS efficiently reduced standard water parameters with the exception of pH, dissolved oxygen, and nitrate whose values increased from raw influent to final effluent. The following water quality parameters were established for the final effluent: total suspended solids 55 ± 7.1 mg. L-1 (n = 28); chemical oxygen demand 94.1 ± 10.6 mg. L-1 (n = 28) (after removal of algae); pH 9.9 ± 0.01 (n = 26); ammonium nitrogen 1.7 ± 0.3 mg. L-1 (n = 25); nitrate 3.3 ± 0.6 mg. L-1 (n = 25); ortho-phosphate 1.6 ± 0.2 mg. L-1 (n = 25); electrical conductivity 98.7 ± 2.0 mS m-1 (n = 26) and faecal coliforms (per 100 mL) 1482.6 ± 636.0 (n = 24). The final effluent measured consistently high chemical oxygen demand and total suspended solids, however close analysis showed that total suspended solids could be controlled by increasing the frequency of removal of settled biomass within the settling ponds. Biomass produced contained microalgae, bacteria, metazoa, and protozoa. The biomass productivity achieved was as high as 130.6 kg ha-1 d-1; however, about 33% was lost to the final effluent due to inadequate settling. Results obtained during the course of this study and outcomes of earlier work on IAPS are taken as the baseline to determine parameters needed for the development of the process audit framework. Techniques utilised to derive the blue print process audit protocol for IAPS included a turtle diagram, a flow diagram and a checklist. Attention to plant management proved vital in determining overall performance. Cost, including operating and maintenance, of treating water using the demonstration scale system on a per person equivalent per year basis was determined as ZAR 123.87 (where, ZAR to USD = 0.07).
- Full Text:
- Date Issued: 2020
Petits récits: creative perspectives of Chinese encounters in Zambia
- Authors: Mwaba, Stary
- Date: 2020
- Subjects: Personal narratives , Lyotard, Jean-François, 1924-1998 , Art and society -- Zambia , Social practice (Art) -- Zambia , Art and globalization -- Zambia , China -- Relations -- Zambia , Storytelling in art , Colonization in art
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/146355 , vital:38518
- Description: This mini-thesis, which supports my MFA exhibition Black Mountain, articulates on-the- ground creative perspectives of the Zambia-China discourse, through the representation of little narratives - les petits récits - connected to personal experiences. Through my creative production as an artist, I respond to perceptions of the Chinese presence in Africa. I utilize historical and contemporary personal narratives to complicate existing perceptions of Chinese presence in my home context of Zambia. “Petit récits”, or “little narratives”, in Francois Lyotard’s term, refers to personal stories of individuals that subvert dominant master-narratives and their legitimization in social-cultural structure. In the case of China’s presence in Zambia, I refer to the dichotomized narratives in the media as metanarratives which pay little attention to the people on the ground and propose the approach of “little narratives” to foreground the lived experiences of Zambians who have individual encounters with Chinese in various social spaces. By employing the narratives of my family members through installations, paintings, and drawings, I intervene in a broader China-Africa discourse that is often driven by economics and politics, and I attach importance to the little narratives. In my thesis I divide my material into three chapters; each chapter grows out of an encounter with the presence of China (and Chinese people) in Zambia in relation to the very personal narratives of family members - Zoë my daughter, my grandma, and Ngolo my cousin. The first chapter focuses on my work Chinese Cabbage as my entry point to this topic, which is based on a school experiment I did with my daughter Zoë. In this chapter I also discuss the current discourses around China’s presence. Chapter two revisits the Zambian-Chinese historical encounters in memory of my grandma’s insaka stories about the construction of TAZARA Railway, and thus my works discussed in this chapter attach importance to the individual engagements from a historical perspective. Chapter three discusses in particular the controversial issues around Black Mountain and the works inspired by my cousin Ngolo’s stories of mining in Black Mountain and dealing with the Chinese traders.
- Full Text:
- Date Issued: 2020
- Authors: Mwaba, Stary
- Date: 2020
- Subjects: Personal narratives , Lyotard, Jean-François, 1924-1998 , Art and society -- Zambia , Social practice (Art) -- Zambia , Art and globalization -- Zambia , China -- Relations -- Zambia , Storytelling in art , Colonization in art
- Language: English
- Type: Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/146355 , vital:38518
- Description: This mini-thesis, which supports my MFA exhibition Black Mountain, articulates on-the- ground creative perspectives of the Zambia-China discourse, through the representation of little narratives - les petits récits - connected to personal experiences. Through my creative production as an artist, I respond to perceptions of the Chinese presence in Africa. I utilize historical and contemporary personal narratives to complicate existing perceptions of Chinese presence in my home context of Zambia. “Petit récits”, or “little narratives”, in Francois Lyotard’s term, refers to personal stories of individuals that subvert dominant master-narratives and their legitimization in social-cultural structure. In the case of China’s presence in Zambia, I refer to the dichotomized narratives in the media as metanarratives which pay little attention to the people on the ground and propose the approach of “little narratives” to foreground the lived experiences of Zambians who have individual encounters with Chinese in various social spaces. By employing the narratives of my family members through installations, paintings, and drawings, I intervene in a broader China-Africa discourse that is often driven by economics and politics, and I attach importance to the little narratives. In my thesis I divide my material into three chapters; each chapter grows out of an encounter with the presence of China (and Chinese people) in Zambia in relation to the very personal narratives of family members - Zoë my daughter, my grandma, and Ngolo my cousin. The first chapter focuses on my work Chinese Cabbage as my entry point to this topic, which is based on a school experiment I did with my daughter Zoë. In this chapter I also discuss the current discourses around China’s presence. Chapter two revisits the Zambian-Chinese historical encounters in memory of my grandma’s insaka stories about the construction of TAZARA Railway, and thus my works discussed in this chapter attach importance to the individual engagements from a historical perspective. Chapter three discusses in particular the controversial issues around Black Mountain and the works inspired by my cousin Ngolo’s stories of mining in Black Mountain and dealing with the Chinese traders.
- Full Text:
- Date Issued: 2020
Petrographic and geochemical characterisation of the hangingwall and the footwall rocks (the Dipeta and R.A.T. stratigraphic units) to the Kinsevere and Nambulwa copper ore deposits of the Lufilian Arc, southern Democratic Republic of Congo
- Authors: Nkulu, Robert Kankomba
- Date: 2020
- Subjects: Petrogenesis -- Congo (Democratic Republic) , Analytical geochemistry -- Congo (Democratic Republic) , Copper ores -- Congo (Democratic Republic) , Ore deposits -- Congo (Democratic Republic) , Katangan Sequence , Geological mapping -- Congo (Democratic Republic) , Central African Copperbelt (Congo and Zambia) , Lufilian Arc , Neoproterozoic Katangan R.A.T. (Roches Argilo Talqueuse) Subgroup , Dipeta Subgroup
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/142772 , vital:38115
- Description: The Kinsevere and Nambulwa copper deposits in the Democratic Republic of Congo (D.R.C.) are set in the eastern side of the Neoproterozoic Katanga Supergroup, forming the Lufilian Arc, resulting from a cratonic collision between the Congo and the Kalahari Cratons (ca.620-570_Ma). The Katanga Supergroup was deposited in an extensional rift setting with a sedimentary thickness succession ranging between 7 to 10 km, sub-divided into: − the Roan, the Nguba and the Kundelungu Groups. The stratigraphic column of the Roan Group consists of the R.A.T. (Roche Argilo Talqueuse), the Mines, the Dipeta and the Mwashya Subgroups. Three major deformation phases have been described characterised by complex multiphase tectonics related to a curved superposition of folded, thrust and sheared blocks. The rocks of the R.A.T., Mines and Dipeta Subgroups are recognised as blocks that occur within a stratiform to discordant and diapiritic megabreccia. The blocks were rafted upward with salt tectonics, resulting in the juxtaposition with the hangingwall and the footwall terranes. Therefore, in that context it has been found that the Dipeta may appear overlying the R.A.T. Subgroup through the unconformity decollement surface of heterogeneous breccia. The petrographic observations made of the R.A.T. and Dipeta samples indicates in both units the presence of detrital quartz and feldspar that have been altered and replaced by sericite and muscovite minerals. Gypsum is intimately associated with magnesite, showing an evaporitic environment domain, while magnesite is common as alteration phase both in the R.A.T. and Dipeta Subgroups. Pyrophyllite has been observed in the Dipeta, resulting from reaction of silica with the Kaolinite at low temperature. Accessory detrital minerals include zircon, as well as xenotime intergrown with altered Fe-Ti-oxide hematite, forming complex textures with disseminated Ti-oxides both in R.A.T. and Dipeta units. Major and trace element geochemistry indicates that the Dipeta is more dolomitic and magnesite while the R.A.T. is clay-rich. The Ti2O value of Dipeta and R.A.T samples is relatively low, ranging between 0.36 and 0.69 wt.% respectively, which suggest highly evolved felsic material in the protolith. This is consistent with interpretation based on the Al2O3/TiO2 ratio, which ranges between 18 and 23 for the R.A.T. and Dipeta respectively, indicating an intermediate to felsic granitoids as the protolith of R.A.T. and Dipeta siltstones. The Ti/Zr ratio of R.A.T. and Dipeta samples of less than 10, while, the higher La/Sc ratio of between 2.6 and 5.5 (for the R.A.T. and Dipeta respectively) indicate that both the R.A.T. and Dipeta are active continental and passive margin tectonic setting. Based on the geochemical variation with depth across the R.A.T. and Dipeta and their contact zone, a geochemical fingerprinting suggests that the ratio TiO2/Al2O3 appears to be useful and could be considered as a stratigraphic geochemical maker able to discriminate the R.A.T. and the Dipeta Subgroups during the geological mapping.
- Full Text:
- Date Issued: 2020
- Authors: Nkulu, Robert Kankomba
- Date: 2020
- Subjects: Petrogenesis -- Congo (Democratic Republic) , Analytical geochemistry -- Congo (Democratic Republic) , Copper ores -- Congo (Democratic Republic) , Ore deposits -- Congo (Democratic Republic) , Katangan Sequence , Geological mapping -- Congo (Democratic Republic) , Central African Copperbelt (Congo and Zambia) , Lufilian Arc , Neoproterozoic Katangan R.A.T. (Roches Argilo Talqueuse) Subgroup , Dipeta Subgroup
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/142772 , vital:38115
- Description: The Kinsevere and Nambulwa copper deposits in the Democratic Republic of Congo (D.R.C.) are set in the eastern side of the Neoproterozoic Katanga Supergroup, forming the Lufilian Arc, resulting from a cratonic collision between the Congo and the Kalahari Cratons (ca.620-570_Ma). The Katanga Supergroup was deposited in an extensional rift setting with a sedimentary thickness succession ranging between 7 to 10 km, sub-divided into: − the Roan, the Nguba and the Kundelungu Groups. The stratigraphic column of the Roan Group consists of the R.A.T. (Roche Argilo Talqueuse), the Mines, the Dipeta and the Mwashya Subgroups. Three major deformation phases have been described characterised by complex multiphase tectonics related to a curved superposition of folded, thrust and sheared blocks. The rocks of the R.A.T., Mines and Dipeta Subgroups are recognised as blocks that occur within a stratiform to discordant and diapiritic megabreccia. The blocks were rafted upward with salt tectonics, resulting in the juxtaposition with the hangingwall and the footwall terranes. Therefore, in that context it has been found that the Dipeta may appear overlying the R.A.T. Subgroup through the unconformity decollement surface of heterogeneous breccia. The petrographic observations made of the R.A.T. and Dipeta samples indicates in both units the presence of detrital quartz and feldspar that have been altered and replaced by sericite and muscovite minerals. Gypsum is intimately associated with magnesite, showing an evaporitic environment domain, while magnesite is common as alteration phase both in the R.A.T. and Dipeta Subgroups. Pyrophyllite has been observed in the Dipeta, resulting from reaction of silica with the Kaolinite at low temperature. Accessory detrital minerals include zircon, as well as xenotime intergrown with altered Fe-Ti-oxide hematite, forming complex textures with disseminated Ti-oxides both in R.A.T. and Dipeta units. Major and trace element geochemistry indicates that the Dipeta is more dolomitic and magnesite while the R.A.T. is clay-rich. The Ti2O value of Dipeta and R.A.T samples is relatively low, ranging between 0.36 and 0.69 wt.% respectively, which suggest highly evolved felsic material in the protolith. This is consistent with interpretation based on the Al2O3/TiO2 ratio, which ranges between 18 and 23 for the R.A.T. and Dipeta respectively, indicating an intermediate to felsic granitoids as the protolith of R.A.T. and Dipeta siltstones. The Ti/Zr ratio of R.A.T. and Dipeta samples of less than 10, while, the higher La/Sc ratio of between 2.6 and 5.5 (for the R.A.T. and Dipeta respectively) indicate that both the R.A.T. and Dipeta are active continental and passive margin tectonic setting. Based on the geochemical variation with depth across the R.A.T. and Dipeta and their contact zone, a geochemical fingerprinting suggests that the ratio TiO2/Al2O3 appears to be useful and could be considered as a stratigraphic geochemical maker able to discriminate the R.A.T. and the Dipeta Subgroups during the geological mapping.
- Full Text:
- Date Issued: 2020
Petrography, metamorphism, deformation and P-T conditions in the western arm of the Lufilian Arc - Zambezi, north-western Zambia
- Authors: Chilekwa, Mwango
- Date: 2020
- Subjects: Petrogenesis -- Zambia -- Zambezi District , Metamorphism (Geology) -- Zambia -- Zambezi District , Petrology -- Zambia -- Zambezi District , Formations (Geology) -- Zambia -- Zambezi District , Rock deformation -- Zambia -- Zambezi District , Lufilian Arc , Neoproterozoic Katangan R.A.T. (Roches Argilo Talqueuse) Subgroup
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/161971 , vital:40699
- Description: The Zambezi area in north-western Zambia is underlain by Neoproterozoic Katanga Supergroup and older, Archean to Mesoproterozoic Basement Supergroup rocks. The area lies within the Domes Region, which is a structural domain of the Lufilian Arc. The stratigraphic succession within Zambezi area is dominated by the Grand Conglomerate Formation (GC) and Mwashia Group which are the most extensive units, and the less abundant Lower and Upper Roan Groups of the Katanga Supergroup. They wrap around the domal Basement Supergroup units. The mineral assemblage of the Mwashia and the GC schists commonly contains garnet, anthophyllite and biotite. GC rocks show remnants of primary structures such as clasts and sedimentary features. Anthophyllite, garnet and biotite are the dominant Mg-Fe rich metamorphic minerals. However, these are iron rich for each mineral phase and has been attributed to iron rich protoliths. The earliest recognised deformation episode (D1) formed NE-SW S1 foliations within GC which is consistent with the regional structural trend in the western Lufilian Arc. S1 was later affected by D2 that generated downward facing F2 folds and S2 foliations. The other associated feature to D2 is garnet that grew as the result of pro-grade metamorphism. The D3 deformation fabric is not developed and did not affect much of the structural geometry of the Zambezi area. The peak assemblages of the Basement Supergroup and the Katanga Supergroup formed at mid-amphibolite facies conditions of 590 °C and 630 °C at an average pressure of 4.0 kbar. The Basement Supergroup has undergone retrograde metamorphism to greenschist facies condition indicated by presence of chlorite and also determined by biotite-anorthite isopleth in THERIAK DOMINO. At the eastern part of Zambezi area, the Katanga Supergroup rocks were retrogressed in the upper greenschist facies at about ~470°C and ~4.0 kbar due to isobaric cooling.
- Full Text:
- Date Issued: 2020
- Authors: Chilekwa, Mwango
- Date: 2020
- Subjects: Petrogenesis -- Zambia -- Zambezi District , Metamorphism (Geology) -- Zambia -- Zambezi District , Petrology -- Zambia -- Zambezi District , Formations (Geology) -- Zambia -- Zambezi District , Rock deformation -- Zambia -- Zambezi District , Lufilian Arc , Neoproterozoic Katangan R.A.T. (Roches Argilo Talqueuse) Subgroup
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/161971 , vital:40699
- Description: The Zambezi area in north-western Zambia is underlain by Neoproterozoic Katanga Supergroup and older, Archean to Mesoproterozoic Basement Supergroup rocks. The area lies within the Domes Region, which is a structural domain of the Lufilian Arc. The stratigraphic succession within Zambezi area is dominated by the Grand Conglomerate Formation (GC) and Mwashia Group which are the most extensive units, and the less abundant Lower and Upper Roan Groups of the Katanga Supergroup. They wrap around the domal Basement Supergroup units. The mineral assemblage of the Mwashia and the GC schists commonly contains garnet, anthophyllite and biotite. GC rocks show remnants of primary structures such as clasts and sedimentary features. Anthophyllite, garnet and biotite are the dominant Mg-Fe rich metamorphic minerals. However, these are iron rich for each mineral phase and has been attributed to iron rich protoliths. The earliest recognised deformation episode (D1) formed NE-SW S1 foliations within GC which is consistent with the regional structural trend in the western Lufilian Arc. S1 was later affected by D2 that generated downward facing F2 folds and S2 foliations. The other associated feature to D2 is garnet that grew as the result of pro-grade metamorphism. The D3 deformation fabric is not developed and did not affect much of the structural geometry of the Zambezi area. The peak assemblages of the Basement Supergroup and the Katanga Supergroup formed at mid-amphibolite facies conditions of 590 °C and 630 °C at an average pressure of 4.0 kbar. The Basement Supergroup has undergone retrograde metamorphism to greenschist facies condition indicated by presence of chlorite and also determined by biotite-anorthite isopleth in THERIAK DOMINO. At the eastern part of Zambezi area, the Katanga Supergroup rocks were retrogressed in the upper greenschist facies at about ~470°C and ~4.0 kbar due to isobaric cooling.
- Full Text:
- Date Issued: 2020
Photo-physicochemical characterization and in vitro Photodynamic Therapy Activity of Phthalocyanine-Graphene Quantum Dots Conjugates
- Authors: Nene, Lindokuhle Cindy
- Date: 2020
- Subjects: Photochemotherapy , Cancer -- Chemotherapy , Quantum dots , Graphene , Nanomedicine
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/140463 , vital:37891
- Description: This thesis reports on the preparation of several differently substituted Zn(II) phthalocyanine (Pc) complexes and their respective graphene quantum dots (GQDs) conjugates. In addition, Pc complexes substituted with biologically active molecules used in cancer therapeutics, namely: benzothiazole and morpholine, were also prepared and conjugated to GQDs. The photo-physicochemical properties were determined for both the complexes and their respective conjugates including the fluorescence/ triplet quantum yields and lifetimes as well as the singlet oxygen generating abilities. Upon conjugation to GQDs, the fluorescence of the Pc complexes decreased (insignificant decrease in some cases), with an increase in the triplet quantum yields. However, the singlet quantum yields of the Pcs in the conjugates did not show an increase with the increase in the triplet quantum yields. This is suspected to be due to the screening effect. The cytotoxicity of the complexes in vitro decreased upon conjugation, as a result of reduced actual number of Pc units provided in the conjugate for therapy. An increase in the efficacy upon quaternization was observed, and a relatively better performance was also observed for the cationic complex in combination with the biotin- functionalized GQDs, 7-GQDs-Biotin. Moreover, the cellular uptake of 7-GQDs-Biotin over 24 h was relatively high compared to complexes alone and other Pcs-GQDs conjugates.
- Full Text:
- Date Issued: 2020
- Authors: Nene, Lindokuhle Cindy
- Date: 2020
- Subjects: Photochemotherapy , Cancer -- Chemotherapy , Quantum dots , Graphene , Nanomedicine
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/140463 , vital:37891
- Description: This thesis reports on the preparation of several differently substituted Zn(II) phthalocyanine (Pc) complexes and their respective graphene quantum dots (GQDs) conjugates. In addition, Pc complexes substituted with biologically active molecules used in cancer therapeutics, namely: benzothiazole and morpholine, were also prepared and conjugated to GQDs. The photo-physicochemical properties were determined for both the complexes and their respective conjugates including the fluorescence/ triplet quantum yields and lifetimes as well as the singlet oxygen generating abilities. Upon conjugation to GQDs, the fluorescence of the Pc complexes decreased (insignificant decrease in some cases), with an increase in the triplet quantum yields. However, the singlet quantum yields of the Pcs in the conjugates did not show an increase with the increase in the triplet quantum yields. This is suspected to be due to the screening effect. The cytotoxicity of the complexes in vitro decreased upon conjugation, as a result of reduced actual number of Pc units provided in the conjugate for therapy. An increase in the efficacy upon quaternization was observed, and a relatively better performance was also observed for the cationic complex in combination with the biotin- functionalized GQDs, 7-GQDs-Biotin. Moreover, the cellular uptake of 7-GQDs-Biotin over 24 h was relatively high compared to complexes alone and other Pcs-GQDs conjugates.
- Full Text:
- Date Issued: 2020
Photocatalysis of 4-chloro and 4-nonylphenols using novel symmetric phthalocyanines and asymmetric porphyrin supported on polyacrylonitrite nanofibres
- Authors: Jones, Benjamin Martin
- Date: 2020
- Subjects: Nanoparticles , Phthalocyanines , Electrospinning , Porphyrins , Nanofibers , Photocatalysis , Photocatalysis -- Environmental aspects
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164770 , vital:41163
- Description: This work explores the synthesis and characterisation of novel symmetrical phthalocyanines and novel asymmetric porphyrins that have been embedded or linked respectively,and electrospun into fibres for application in the photocatalysis of environmental pollutants. The phthalocyanines contain pyrrole moieties without hetero atom linkers to maintain a rigid structure. The porphyrin contains a carboxy moiety utilized to construct an amide bond between the complex and the polymer prior to the spinning process. The new compounds were characterized by elemental analyses, proton nuclear magnetic resonance (HNMR)Fourier-transform infrared spectroscopy (FTIR), MALDI-TOF and UV-vis spectroscopy. The general trends of fluorescence, triplet and singlet oxygen quantum yields are described as well as their appropriate lifetimes. The photocatalytic activity of phthalocyanine embedded fibres were compared against those that had been dyed. Unfortunately, during the degradation process, the dyed fibres leeched compound and the studies could not be continued. It was seen that the porphyrin fibres linked to the polymer showed the most efficient photocatalytic activity against 4-cholorphenol and 4-nonylphenol due to irradiation at lower wavelengths consequently having higher frequencies and transferring more energy.
- Full Text:
- Date Issued: 2020
- Authors: Jones, Benjamin Martin
- Date: 2020
- Subjects: Nanoparticles , Phthalocyanines , Electrospinning , Porphyrins , Nanofibers , Photocatalysis , Photocatalysis -- Environmental aspects
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/164770 , vital:41163
- Description: This work explores the synthesis and characterisation of novel symmetrical phthalocyanines and novel asymmetric porphyrins that have been embedded or linked respectively,and electrospun into fibres for application in the photocatalysis of environmental pollutants. The phthalocyanines contain pyrrole moieties without hetero atom linkers to maintain a rigid structure. The porphyrin contains a carboxy moiety utilized to construct an amide bond between the complex and the polymer prior to the spinning process. The new compounds were characterized by elemental analyses, proton nuclear magnetic resonance (HNMR)Fourier-transform infrared spectroscopy (FTIR), MALDI-TOF and UV-vis spectroscopy. The general trends of fluorescence, triplet and singlet oxygen quantum yields are described as well as their appropriate lifetimes. The photocatalytic activity of phthalocyanine embedded fibres were compared against those that had been dyed. Unfortunately, during the degradation process, the dyed fibres leeched compound and the studies could not be continued. It was seen that the porphyrin fibres linked to the polymer showed the most efficient photocatalytic activity against 4-cholorphenol and 4-nonylphenol due to irradiation at lower wavelengths consequently having higher frequencies and transferring more energy.
- Full Text:
- Date Issued: 2020
Poor whites and the post-apartheid labour market: a study of perceptions and experiences of work among residents in a homeless shelter in Johannesburg
- Authors: Wollnik, Nadjeschda
- Date: 2020
- Subjects: Poor whites -- South Africa , Poor whites -- South Africa -- Atitudes , Shelters for the homeless -- South Africa , Unemployed -- South Africa -- Attitudes , Unemployed -- South Africa , South Africa -- Social conditions -- 1994- , South Africa -- Economic conditions -- 1991-
- Language: English
- Type: text , Thesis , Masters , MSocSci
- Identifier: http://hdl.handle.net/10962/148540 , vital:38748
- Description: Despite historical precedents, poverty among white people in South Africa remains an anomaly and a paradox. Likewise, the perceptions of work and employment among poor (under- and unemployed) whites in contemporary South Africa have received scant attention in the scholarly literature. Using the conceptual frameworks of critical whiteness studies and segmented labour market theory – as a way of combining subjective and objective considerations – this research seeks to describe and explain the perceptions and experiences of the labour market among poor whites living in a homeless shelter in Johannesburg. Eight respondents were chosen for extended, in-depth interviews in an effort to develop a fine-grained understanding of the pre-existing circumstances that affected their access to information and thus shaped their choices in the labour market, as well as to ascertain what they believed to be the barriers that they face in the labour market. The findings varied, with most of the interviewees seeing ‘being white’ as the reason for their poverty and unemployment, while others exhibited some awareness of the role of their lack of skills and qualifications in their capacity to compete in higher segments of the labour market. The findings were also varied in the sense that not all interviewees experienced poverty in the same manner, with some having been part of the middle class prior to becoming poor, while others having been poor their entire lives. It was also found that class or socio-economic status seemed to have a greater impact than race on the labour market prospects of the interviewees. It is argued that the perceptions of these poor whites, which are informed by their lack of information about the workings of the labour market, rather than their lack of qualifications or their race, most affected their prospects in the labour market. The mechanisms they rely on when seeking employment reveal a poor knowledge of the local labour market and the ways in which they think their skillsets match up to the types of jobs they desire. The lack of understanding of the South African labour market and the policies that are in place to redress the legacies of apartheid are among the factors influencing the lack of success these poor whites are experiencing in their search for work.
- Full Text:
- Date Issued: 2020
- Authors: Wollnik, Nadjeschda
- Date: 2020
- Subjects: Poor whites -- South Africa , Poor whites -- South Africa -- Atitudes , Shelters for the homeless -- South Africa , Unemployed -- South Africa -- Attitudes , Unemployed -- South Africa , South Africa -- Social conditions -- 1994- , South Africa -- Economic conditions -- 1991-
- Language: English
- Type: text , Thesis , Masters , MSocSci
- Identifier: http://hdl.handle.net/10962/148540 , vital:38748
- Description: Despite historical precedents, poverty among white people in South Africa remains an anomaly and a paradox. Likewise, the perceptions of work and employment among poor (under- and unemployed) whites in contemporary South Africa have received scant attention in the scholarly literature. Using the conceptual frameworks of critical whiteness studies and segmented labour market theory – as a way of combining subjective and objective considerations – this research seeks to describe and explain the perceptions and experiences of the labour market among poor whites living in a homeless shelter in Johannesburg. Eight respondents were chosen for extended, in-depth interviews in an effort to develop a fine-grained understanding of the pre-existing circumstances that affected their access to information and thus shaped their choices in the labour market, as well as to ascertain what they believed to be the barriers that they face in the labour market. The findings varied, with most of the interviewees seeing ‘being white’ as the reason for their poverty and unemployment, while others exhibited some awareness of the role of their lack of skills and qualifications in their capacity to compete in higher segments of the labour market. The findings were also varied in the sense that not all interviewees experienced poverty in the same manner, with some having been part of the middle class prior to becoming poor, while others having been poor their entire lives. It was also found that class or socio-economic status seemed to have a greater impact than race on the labour market prospects of the interviewees. It is argued that the perceptions of these poor whites, which are informed by their lack of information about the workings of the labour market, rather than their lack of qualifications or their race, most affected their prospects in the labour market. The mechanisms they rely on when seeking employment reveal a poor knowledge of the local labour market and the ways in which they think their skillsets match up to the types of jobs they desire. The lack of understanding of the South African labour market and the policies that are in place to redress the legacies of apartheid are among the factors influencing the lack of success these poor whites are experiencing in their search for work.
- Full Text:
- Date Issued: 2020
Power in Africa: a comparison of selected South African and Nigerian dystopian fiction
- Authors: Simelane, Smangaliso
- Date: 2020
- Subjects: Dystopias in literature , Africa -- In literature , South African fiction (English) -- History and criticism , Nigerian fiction (English) -- History and criticism , Beukes, Lauren -- Moxyland , Herne, Lily -- Deadlands , Bandele-Thomas, Biyi, 1967- The Sympathetic Undertaker and Other Dreams , Bandele-Thomas, Biyi, 1967- The Man Who Came in from the Back of Beyond
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/148171 , vital:38716
- Description: Dystopias have frequently been explored in literature to better understand the present and imagine the effects of certain elements of society if taken to a logical extreme. In this way, dystopian fiction can act as both cautionary tales and a form of social commentary. This can be explored within the context of African dystopian fiction where power is a recurring theme, highlighting the anxiety and turbulent history several countries on the continent continue to face. To demonstrate this, I compare selected South African and Nigerian Dystopian texts. With regards to South Africa, I analyse novels by South African science fiction authors Lauren Beukes and Lily Herne, namely Moxyland (2008) and Deadlands (2011) respectively, to investigate how South Africa’s past under Apartheid shapes the segregated societies presented. Nigerian dystopian texts by Biyi Bandele-Thomas, namely The Sympathetic Undertaker And Other Dreams (1993) and The Man Who Came in from the Back of Beyond (1992), are discussed with regards to the way Nigeria’s colonial past and several military juntas have contributed to the kinds of corruption that are depicted. I argue that all four texts warn of the dangers of power, albeit in ways that pertain specifically to their countries of origin. With regards to the South African texts, readers are shown the ways in which those in power can manipulate the desire to survive to keep those they subjugate dependent and, consequently, obedient through what Judith Butler terms ‘passionate attachments’. In the case of the Nigerian dystopias, I argue that Bandele-Thomas’s texts warn of tyranny and effects of the corruption that result from misused power strategies. While the dire settings of dystopian fiction may be grim enough, on their own, to motivate change in the real world, this may not be enough to prevent the texts from becoming pessimistic and fatalistic outlooks. Hence, I seek to understand how the selected novels maintain hope and, consequently, convince readers that the depicted dystopias are ones that can be avoided. Typically, dystopian literature fosters hope by setting the narratives in the future, giving readers hope that they may take steps today to protect their societies from becoming like the damned worlds described by dystopian authors. However, the selected texts are not set in the future. Hence, I explore three literary techniques that might foster hope within the selected African dystopian texts in lieu of temporal distancing. They are, namely: identification with the protagonist, defamiliarization and cognitive estrangement.
- Full Text:
- Date Issued: 2020
- Authors: Simelane, Smangaliso
- Date: 2020
- Subjects: Dystopias in literature , Africa -- In literature , South African fiction (English) -- History and criticism , Nigerian fiction (English) -- History and criticism , Beukes, Lauren -- Moxyland , Herne, Lily -- Deadlands , Bandele-Thomas, Biyi, 1967- The Sympathetic Undertaker and Other Dreams , Bandele-Thomas, Biyi, 1967- The Man Who Came in from the Back of Beyond
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/148171 , vital:38716
- Description: Dystopias have frequently been explored in literature to better understand the present and imagine the effects of certain elements of society if taken to a logical extreme. In this way, dystopian fiction can act as both cautionary tales and a form of social commentary. This can be explored within the context of African dystopian fiction where power is a recurring theme, highlighting the anxiety and turbulent history several countries on the continent continue to face. To demonstrate this, I compare selected South African and Nigerian Dystopian texts. With regards to South Africa, I analyse novels by South African science fiction authors Lauren Beukes and Lily Herne, namely Moxyland (2008) and Deadlands (2011) respectively, to investigate how South Africa’s past under Apartheid shapes the segregated societies presented. Nigerian dystopian texts by Biyi Bandele-Thomas, namely The Sympathetic Undertaker And Other Dreams (1993) and The Man Who Came in from the Back of Beyond (1992), are discussed with regards to the way Nigeria’s colonial past and several military juntas have contributed to the kinds of corruption that are depicted. I argue that all four texts warn of the dangers of power, albeit in ways that pertain specifically to their countries of origin. With regards to the South African texts, readers are shown the ways in which those in power can manipulate the desire to survive to keep those they subjugate dependent and, consequently, obedient through what Judith Butler terms ‘passionate attachments’. In the case of the Nigerian dystopias, I argue that Bandele-Thomas’s texts warn of tyranny and effects of the corruption that result from misused power strategies. While the dire settings of dystopian fiction may be grim enough, on their own, to motivate change in the real world, this may not be enough to prevent the texts from becoming pessimistic and fatalistic outlooks. Hence, I seek to understand how the selected novels maintain hope and, consequently, convince readers that the depicted dystopias are ones that can be avoided. Typically, dystopian literature fosters hope by setting the narratives in the future, giving readers hope that they may take steps today to protect their societies from becoming like the damned worlds described by dystopian authors. However, the selected texts are not set in the future. Hence, I explore three literary techniques that might foster hope within the selected African dystopian texts in lieu of temporal distancing. They are, namely: identification with the protagonist, defamiliarization and cognitive estrangement.
- Full Text:
- Date Issued: 2020