Making South African tertiary education multilingual: the implementation, monitoring and evaluation of SANTED Multilingualism Projects 2007 – 2010
- Authors: Nosilela, Bulelwa
- Date: 2020
- Subjects: South Africa-Norway Tertiary Education Development Programme , Language policy -- South Africa , Multilingual education -- South Africa , Language and education -- South Africa , Education, Higher -- Social aspects -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PHD
- Identifier: http://hdl.handle.net/10962/140513 , vital:37895
- Description: This thesis focuses on multilingualism as it applies to education, particularly higher education in South Africa. The thesis suggests that language must be seen as critical in education (Obanya, 2004; Wolff, 2006). This thesis also suggests that there is a link between a person’s general competence in an educational environment, and that person’s language competence. In support of other scholars, this thesis also finds that learners from low social classes in society have a restricted linguistic code and therefore the learners from these social classes lack the ability to express themselves in an elaborative manner in a cognitive situation while learners from upper social class have an elaborate linguistic repertoire in the language of instruction, namely English. Even though general policy in South Africa and Africa as a whole recognises this relationship between language and education, this thesis finds that very little is being done to implement these well-meaning policies. The SANTED (South Africa-Norway-Tertiary-Education) programme, which forms the focus of this thesis, is seen as an exception. While there is an increase in the number of learners and students accessing centres of learning, especially those from historically-disadvantaged backgrounds (CHE Higher Education Monitor, 2008), there is at the same time rigorous debate in South Africa at the moment as to whether these learners and students benefit optimally from knowledge offered in centres of learning, and are therefore, not accomplishing success expected from them (Boughey, 2008). This thesis suggests that at the centre of this debate is the understanding that, while there are a variety of factors that might affect their success, for example social and economic status, schooling background in case of students in higher education, language plays a pivotal role. This thesis analyses the challenges and successes which faced the SANTED programme at a number of South African institutions where language issues were brought to the centre of the learning process. The thesis also assesses best practices in various African countries and makes recommendations regarding language-use in Higher Education, as part of a transformationprocess. The collaboration between the South African and Norwegian governments provided impetus to policy implementation. It also had other focus areas such as capacity building, access, success and retention and collaboration with Southern African Developing Countries (SADC). This thesis shows, through a critical analysis of SANTED, that it represented an important intervention regarding the promotion of multilingualism.
- Full Text:
- Date Issued: 2020
- Authors: Nosilela, Bulelwa
- Date: 2020
- Subjects: South Africa-Norway Tertiary Education Development Programme , Language policy -- South Africa , Multilingual education -- South Africa , Language and education -- South Africa , Education, Higher -- Social aspects -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PHD
- Identifier: http://hdl.handle.net/10962/140513 , vital:37895
- Description: This thesis focuses on multilingualism as it applies to education, particularly higher education in South Africa. The thesis suggests that language must be seen as critical in education (Obanya, 2004; Wolff, 2006). This thesis also suggests that there is a link between a person’s general competence in an educational environment, and that person’s language competence. In support of other scholars, this thesis also finds that learners from low social classes in society have a restricted linguistic code and therefore the learners from these social classes lack the ability to express themselves in an elaborative manner in a cognitive situation while learners from upper social class have an elaborate linguistic repertoire in the language of instruction, namely English. Even though general policy in South Africa and Africa as a whole recognises this relationship between language and education, this thesis finds that very little is being done to implement these well-meaning policies. The SANTED (South Africa-Norway-Tertiary-Education) programme, which forms the focus of this thesis, is seen as an exception. While there is an increase in the number of learners and students accessing centres of learning, especially those from historically-disadvantaged backgrounds (CHE Higher Education Monitor, 2008), there is at the same time rigorous debate in South Africa at the moment as to whether these learners and students benefit optimally from knowledge offered in centres of learning, and are therefore, not accomplishing success expected from them (Boughey, 2008). This thesis suggests that at the centre of this debate is the understanding that, while there are a variety of factors that might affect their success, for example social and economic status, schooling background in case of students in higher education, language plays a pivotal role. This thesis analyses the challenges and successes which faced the SANTED programme at a number of South African institutions where language issues were brought to the centre of the learning process. The thesis also assesses best practices in various African countries and makes recommendations regarding language-use in Higher Education, as part of a transformationprocess. The collaboration between the South African and Norwegian governments provided impetus to policy implementation. It also had other focus areas such as capacity building, access, success and retention and collaboration with Southern African Developing Countries (SADC). This thesis shows, through a critical analysis of SANTED, that it represented an important intervention regarding the promotion of multilingualism.
- Full Text:
- Date Issued: 2020
Managing the invasive aquatic plant Sagittaria platyphylla (Engelm.) J.G. Sm(Alismataceae): problems and prospects
- Ndlovu, Mpilonhle Sinothando
- Authors: Ndlovu, Mpilonhle Sinothando
- Date: 2020
- Subjects: Aquatic weeds -- Biological control -- South Africa , Sagittaria latifolia -- Biological control -- South Africa , Noxious weeds -- Biological control -- South Africa , Invasive plants -- Biological control -- South Africa , Listronotus , Insects as biological pest control agents
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167121 , vital:41439
- Description: Sagittaria platyphylla (Engelm.) J.G.Sm. (Alismataceae), commonly known as Delta arrowhead, is an invasive aquatic macrophyte native to southern United States of America (USA) that has become a serious weed in freshwater systems in South Africa, New Zealand, Australia, and recently China. In South Africa, the plant was first detected in Krantzkloof Nature Reserve, KwaZulu-Natal Province in 2008, and due to its known impact in other countries, it was listed as a Category 1a invader species under the National Environmental Management: Biodiversity Act 2004 (NEM: BA). This listing required mechanical and chemical control methods to be implemented by the South African National Biodiversity Institute’s (SANBI), Invasive Species Programme (ISP), with the aim of eradicating the weed. Despite the eradication efforts, by 2016, the weed was recognized as one of the country’s top 10 worst and fastest spreading invasive alien plants. Since its introduction in 2008, the plant has spread both within and between sites in South Africa, increasing from one site in 2008 to 72 sites by 2019. Once introduced into lotic systems, the plant spread rapidly downstream, in some cases up to 120km within six years, with an average of 10 km per year. Extirpation over the last ten years was only possible at a limited number of sites. Under the current management approach, the invasion is foreseen to spread to new sites within a 5 km radius of the current populations. Due to the failure of conventional control mechanisms, biological control is currently being considered as a potential control option. Four potential biological control agents are under investigation, but none have been released. Amongst them is the fruit and flower feeding weevil Listronotus appendiculatus Bohm. (Coleoptera: Curculionidae) which showed most potential as a suitable biological control agent. This study demonstrated that L. appendiculatus herbivory negatively influenced the overall fitness of S. platyphylla by reducing the plant’s growth rate and above ground biomass. Listronotus appendiculatus herbivory also reduced the plant’s size and the potential to kill adult plants. Most importantly, L. appendiculatus larval feeding damage significantly reduce viable-germinating seeds, the weed’s primary dispersal mechanism. Therefore, a biological control programme is advised to be integrated within the current management plan.
- Full Text:
- Date Issued: 2020
- Authors: Ndlovu, Mpilonhle Sinothando
- Date: 2020
- Subjects: Aquatic weeds -- Biological control -- South Africa , Sagittaria latifolia -- Biological control -- South Africa , Noxious weeds -- Biological control -- South Africa , Invasive plants -- Biological control -- South Africa , Listronotus , Insects as biological pest control agents
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167121 , vital:41439
- Description: Sagittaria platyphylla (Engelm.) J.G.Sm. (Alismataceae), commonly known as Delta arrowhead, is an invasive aquatic macrophyte native to southern United States of America (USA) that has become a serious weed in freshwater systems in South Africa, New Zealand, Australia, and recently China. In South Africa, the plant was first detected in Krantzkloof Nature Reserve, KwaZulu-Natal Province in 2008, and due to its known impact in other countries, it was listed as a Category 1a invader species under the National Environmental Management: Biodiversity Act 2004 (NEM: BA). This listing required mechanical and chemical control methods to be implemented by the South African National Biodiversity Institute’s (SANBI), Invasive Species Programme (ISP), with the aim of eradicating the weed. Despite the eradication efforts, by 2016, the weed was recognized as one of the country’s top 10 worst and fastest spreading invasive alien plants. Since its introduction in 2008, the plant has spread both within and between sites in South Africa, increasing from one site in 2008 to 72 sites by 2019. Once introduced into lotic systems, the plant spread rapidly downstream, in some cases up to 120km within six years, with an average of 10 km per year. Extirpation over the last ten years was only possible at a limited number of sites. Under the current management approach, the invasion is foreseen to spread to new sites within a 5 km radius of the current populations. Due to the failure of conventional control mechanisms, biological control is currently being considered as a potential control option. Four potential biological control agents are under investigation, but none have been released. Amongst them is the fruit and flower feeding weevil Listronotus appendiculatus Bohm. (Coleoptera: Curculionidae) which showed most potential as a suitable biological control agent. This study demonstrated that L. appendiculatus herbivory negatively influenced the overall fitness of S. platyphylla by reducing the plant’s growth rate and above ground biomass. Listronotus appendiculatus herbivory also reduced the plant’s size and the potential to kill adult plants. Most importantly, L. appendiculatus larval feeding damage significantly reduce viable-germinating seeds, the weed’s primary dispersal mechanism. Therefore, a biological control programme is advised to be integrated within the current management plan.
- Full Text:
- Date Issued: 2020
Market timing and portfolio returns: an empirical analysis of the potential profitability of buy-sell strategies, based on South African equities 2009-2018
- Authors: Mulweli, Ramulongo
- Date: 2020
- Subjects: Johannesburg Stock Exchange , Stocks -- Charts, diagrams, etc. , Investment analysis -- South Africa , Stocks -- South Africa , Stocks -- South Africa -- Cast studies
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/144487 , vital:38350
- Description: South Africa’s financial markets have become larger and more complex over recent decades. The number of market participants who are using technical analysis techniques to predict the market’s movement has been growing rapidly. This research aims to investigate if historical share prices can be used when forecasting the market’s direction and to examine the profitability of the Japanese candlestick patterns. The study is based on ten companies selected from the JSE top 40 2019 composition. These are Aspen Pharmacy Holding, Capitec Bank Holding LTD, Discovery LTD, Kumba Iron Ore LTD, Mondi PLC, Mr. Price Group LTD, MTN Group LTD, Naspers LTD, SASOL LTD, and Shoprite Holdings LTD. These were selected from the JSE top 40 based on market capitalization and sector. This research analyzes eight candlestick reversal patterns; four are bullish patterns namely: doji star, hammer, bullish engulfing and the piercing lines and the other four are bearish patterns namely: shooting star, hanging man, bearish engulfing and the dark cloud cover. The ARCH and GARCH models are used to test for correlation between past share prices and future share prices and the binomial test and the mean return calculations were used to test the profitability of candlestick patterns. The sample is from Thomson DataStream 2019 and IRESS SA 2019 and covers ten years with 2496 observations starting from 02 January 2009 to 31 December 2018. The findings from the ARCH and GARCH tests revealed that there is a serial correlation between the returns from the previous day and the returns for the current day. The results from the mean returns and the binomial tests show strong evidence that the shooting star, hanging man, bearish engulfing and the bulling engulfing are statistically significant in predicting the share price movements. On the other hand, there was no evidence that the dark cloud cover, piercing lines, and the bullish doji can predict share price movements. Additionally, further studies on this topic could be improved by adding different candlestick patterns and the total number of companies analyzed. The results could also be improved by analyzing the candlestick reversal patterns when they are used with other trading rules such as support resistance levels and oscillators.
- Full Text:
- Date Issued: 2020
- Authors: Mulweli, Ramulongo
- Date: 2020
- Subjects: Johannesburg Stock Exchange , Stocks -- Charts, diagrams, etc. , Investment analysis -- South Africa , Stocks -- South Africa , Stocks -- South Africa -- Cast studies
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/144487 , vital:38350
- Description: South Africa’s financial markets have become larger and more complex over recent decades. The number of market participants who are using technical analysis techniques to predict the market’s movement has been growing rapidly. This research aims to investigate if historical share prices can be used when forecasting the market’s direction and to examine the profitability of the Japanese candlestick patterns. The study is based on ten companies selected from the JSE top 40 2019 composition. These are Aspen Pharmacy Holding, Capitec Bank Holding LTD, Discovery LTD, Kumba Iron Ore LTD, Mondi PLC, Mr. Price Group LTD, MTN Group LTD, Naspers LTD, SASOL LTD, and Shoprite Holdings LTD. These were selected from the JSE top 40 based on market capitalization and sector. This research analyzes eight candlestick reversal patterns; four are bullish patterns namely: doji star, hammer, bullish engulfing and the piercing lines and the other four are bearish patterns namely: shooting star, hanging man, bearish engulfing and the dark cloud cover. The ARCH and GARCH models are used to test for correlation between past share prices and future share prices and the binomial test and the mean return calculations were used to test the profitability of candlestick patterns. The sample is from Thomson DataStream 2019 and IRESS SA 2019 and covers ten years with 2496 observations starting from 02 January 2009 to 31 December 2018. The findings from the ARCH and GARCH tests revealed that there is a serial correlation between the returns from the previous day and the returns for the current day. The results from the mean returns and the binomial tests show strong evidence that the shooting star, hanging man, bearish engulfing and the bulling engulfing are statistically significant in predicting the share price movements. On the other hand, there was no evidence that the dark cloud cover, piercing lines, and the bullish doji can predict share price movements. Additionally, further studies on this topic could be improved by adding different candlestick patterns and the total number of companies analyzed. The results could also be improved by analyzing the candlestick reversal patterns when they are used with other trading rules such as support resistance levels and oscillators.
- Full Text:
- Date Issued: 2020
Mechanism of action of non-synonymous single nucleotide variations associated with α-carbonic anhydrases II, IV and VIII
- Authors: Sanyanga, T. Allan
- Date: 2020
- Subjects: Carbonic anhydrase , Carbonic anhydrase -- Therapeutic use , Nucleotides
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167346 , vital:41470
- Description: The carbonic anhydrase (CA) group of enzymes are Zinc (Zn2+) metalloproteins responsible for the reversible hydration of CO2 to bicarbonate (BCT or HCO− 3 ) and protons (H+) for the facilitation of acid-base balance and homeostasis within the body. Across all organisms, a minimum of six CA families exist, including, α (alpha), β (beta), γ (gamma), δ (delta), η (eta) and ζ (zeta). Some organisms can have more than one family, with exception to humans that contain the α family solely. The α-CA family comprises of 16 isoforms (CA-I to CA-XV) including the CA-VIII, CA-X and CA-XI acatalytic isoforms. Of the catalytic isoforms, CA-II and CA-IV possess one of the fastest rates of reaction, and any disturbances to the function of these enzymes results in CA deficiencies and undesirable phenotypes. CA-II deficiencies result in osteopetrosis with renal tubular acidosis and cerebral calcification, whereas CA-IV deficiencies result in retinitis pigmentosa 17 (RP17). Phenotypic effects generally manifest as a result of poor protein folding and function due to the presence of non-synonymous single nucleotide variations (nsSNVs). Even within the acatalytic isoforms such as CA-VIII that llosterically regulates the affinity of inositol triphosphate (IP3) for the IP3 receptor type 1 (ITPR1) and regulates calcium (Ca2+) signalling, the presence of SNVs also causes phenotypes cerebellar ataxia, mental retardation, and dysequilibrium syndrome 3 (CAMRQ3). Currently the majority of research into the CAs is focused on the inhibition of these proteins to achieve therapeutic effects in patients via the control of HCO− production or reabsorption as observed in glaucoma and diuretic medications. Little research has therefore been devoted into the identification of stabilising or activating compound that could rescue protein function in the case of deficiencies. The main aim of this research was to identify and characterise the effects of nsSNVs on the structure and function of CA-II, CA-IV and CA-VIII to set a foundation for rare disease studies into the CA group of proteins. Combined bioinformatics approaches divided into four main objectives were implemented. These included variant identification, sequence analysis and protein characterisation, force field (FF) parameter generation, molecular dynamics (MD) simulation and dynamic residue network analysis (DRN). Six variants for each of the CA-II, CA-IV and CA-VIII proteins with pathogenic annotations were identified from the HUMA and Ensembl databases. These included the pathogenic variants K18E, K18Q, H107Y, P236H, P236R and N252D for CA-II. CA-IV included the pathogenic R69H, R219C and R219S, and benign N86K, N177K and V234I variants. CA-VIII included pathogenic S100A, S100P, G162R and R237Q, and benign S100L and E109D variants. CA-II has been more extensively studied than CA-IV and CA-VIII, therefore residues essential to its function and stability are known. To discover important residues and regions within the CA-IV and CA-VIII proteins sequence and motif analysis was performed across the α-CA family, using CA-II as a reference. Sequence analysis identified multiple conserved residues between the two acatalytic CA-II and CA-IV, and the acatalytic CA-VIII isoforms that were proposed to be essential for protein stability. With exception to the benign N86K CA-IV variant, none of the other pathogenic or benign CA-II, CA-IV and CA-VIII SNVs were located at functionally or structurally important residues. Motif analysis identified 11 conserved and important motifs within the α-CA family. Several of the identified variants were located on these motifs including K18E, K18Q, H107Y and N252D (CA-II); N86K, R219C, R219S and V234I (CA-IV); and E109D, G162R and R237Q (CA-VIII). As there were no x-ray crystal structures of the variant proteins, homology modelling was performed to calculate the protein structures for characterisation. In CA-VIII, the substitution of Ser for Pro at position 100 (variant S100P) resulted in destruction of the β-sheet that the SNV was located on. Little is known about the mechanism of interaction between CA-VIII and ITPR1, and residues involved. SiteMap and CPORT were used to identify binding site amino for CA-VIII and results identified 38 potential residues. Traditional FFs are incapable of performing MD simulations of metalloproteins. The AMBER ff14SB FF was extended and Zn2+ FF parameters calculated to add support for metalloprotein MD simulations. In the protein, Zn2+ was noted to have a charge less than +1. Variant effects on protein structure were then investigated using MD simulations. Root mean square deviation (RMSD) and radius of gyration (Rg) results indicated subtle SNV effects to the variant global structure in CA-II and CA-IV. However, with regards to CA-VIII RMSD analysis highlighted that variant presence was associated with increases to the structural rigidity of the protein. Principal component analysis (PCA) in conjunction with free energy analysis was performed to observe variant effects on protein conformational sampling in 3D space. The binding of BCT to CA-II induced greater protein conformational sampling and was associated with higher free energy. In CA-IV and CA-VIII PCA analysis revealed key differences in the mechanism of action of pathogenic and benign SNVs. In CA-IV, wild-type (WT) and benign variant protein structures clustered into single low energy well hinting at the presence of more stable structures. Pathogenic variants were associated with higher free energy and proteins sampled more conformations without settling into a low energy well. PCA analysis of CA-VIII indicated the opposite to CA-IV. Pathogenic variants were clustered into low energy wells, while the WT and benign variants showed greater conformational sampling. Dynamic cross correlation (DCC) analysis was performed using the MD-TASK suite to determine variant effects on residue movement. CA-II WT protein revealed that BCT and CO2 were associated with anti-correlated and correlated residue movement, highlighting at opposite mechanisms. In CA-IV and CA-VIII variant presence resulted in a change to residue correlation compared to the WT proteins. DRN analysis was performed to investigate SNV effects of residue accessibility and communication. Results demonstrated that SNVs are associated with allosteric effects on the CA protein structures, and effects are located on the stability assisting residues of the aromatic clusters and the active site of the proteins. CA-II studies discovered that Glu117 is the most important residue for communication, and variant presence results in a decrease to the usage of the residue. This effect was greatest in the CA-II H107Y SNV, and suggests that variants could have an effect on Zn2+ dissociation from the active site. Decreases to the usage of Zn2+ coordinating residues were also noted. Where this occurred, compensatory increases to the usage of other primary and secondary coordination residues were observed, that could possibly assist with the maintenance of Zn2+ within the active site. The CA-IV variants R69H and R219C highlighted potentially similar pathogenic mechanisms, whereas N86K and N177K hinted at potentially similar benign mechanisms. Within CA-VIII, variant presence was associated with changes to the accessibility of the N-terminal binding site residues. The benign CA-VIII variants highlighted possible compensatory mechanisms, whereby as one group of N-terminal residues loses accessibility, there was an increase to the accessibility of other binding site residues to possibly balance the effect. Catalytically, the proton shuttle residue His64 in CA-II was found to occupy a novel conformation named the “faux in” that brought the imidazole group even closer to the Zn2+ compared to the “in” conformation. Overall, compared to traditional MD simulations the incorporation of DRN allowed more detailed investigations into the variant mechanisms of action. This highlights the importance of network analysis in the study of the effects of missense mutations on the structure and function of proteins. Investigations of diseases at the molecular level is essential in the identification of disease pathogenesis and assists with the development of specifically tailored and better treatment options especially in the cases of genetically associated rare diseases.
- Full Text:
- Date Issued: 2020
- Authors: Sanyanga, T. Allan
- Date: 2020
- Subjects: Carbonic anhydrase , Carbonic anhydrase -- Therapeutic use , Nucleotides
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167346 , vital:41470
- Description: The carbonic anhydrase (CA) group of enzymes are Zinc (Zn2+) metalloproteins responsible for the reversible hydration of CO2 to bicarbonate (BCT or HCO− 3 ) and protons (H+) for the facilitation of acid-base balance and homeostasis within the body. Across all organisms, a minimum of six CA families exist, including, α (alpha), β (beta), γ (gamma), δ (delta), η (eta) and ζ (zeta). Some organisms can have more than one family, with exception to humans that contain the α family solely. The α-CA family comprises of 16 isoforms (CA-I to CA-XV) including the CA-VIII, CA-X and CA-XI acatalytic isoforms. Of the catalytic isoforms, CA-II and CA-IV possess one of the fastest rates of reaction, and any disturbances to the function of these enzymes results in CA deficiencies and undesirable phenotypes. CA-II deficiencies result in osteopetrosis with renal tubular acidosis and cerebral calcification, whereas CA-IV deficiencies result in retinitis pigmentosa 17 (RP17). Phenotypic effects generally manifest as a result of poor protein folding and function due to the presence of non-synonymous single nucleotide variations (nsSNVs). Even within the acatalytic isoforms such as CA-VIII that llosterically regulates the affinity of inositol triphosphate (IP3) for the IP3 receptor type 1 (ITPR1) and regulates calcium (Ca2+) signalling, the presence of SNVs also causes phenotypes cerebellar ataxia, mental retardation, and dysequilibrium syndrome 3 (CAMRQ3). Currently the majority of research into the CAs is focused on the inhibition of these proteins to achieve therapeutic effects in patients via the control of HCO− production or reabsorption as observed in glaucoma and diuretic medications. Little research has therefore been devoted into the identification of stabilising or activating compound that could rescue protein function in the case of deficiencies. The main aim of this research was to identify and characterise the effects of nsSNVs on the structure and function of CA-II, CA-IV and CA-VIII to set a foundation for rare disease studies into the CA group of proteins. Combined bioinformatics approaches divided into four main objectives were implemented. These included variant identification, sequence analysis and protein characterisation, force field (FF) parameter generation, molecular dynamics (MD) simulation and dynamic residue network analysis (DRN). Six variants for each of the CA-II, CA-IV and CA-VIII proteins with pathogenic annotations were identified from the HUMA and Ensembl databases. These included the pathogenic variants K18E, K18Q, H107Y, P236H, P236R and N252D for CA-II. CA-IV included the pathogenic R69H, R219C and R219S, and benign N86K, N177K and V234I variants. CA-VIII included pathogenic S100A, S100P, G162R and R237Q, and benign S100L and E109D variants. CA-II has been more extensively studied than CA-IV and CA-VIII, therefore residues essential to its function and stability are known. To discover important residues and regions within the CA-IV and CA-VIII proteins sequence and motif analysis was performed across the α-CA family, using CA-II as a reference. Sequence analysis identified multiple conserved residues between the two acatalytic CA-II and CA-IV, and the acatalytic CA-VIII isoforms that were proposed to be essential for protein stability. With exception to the benign N86K CA-IV variant, none of the other pathogenic or benign CA-II, CA-IV and CA-VIII SNVs were located at functionally or structurally important residues. Motif analysis identified 11 conserved and important motifs within the α-CA family. Several of the identified variants were located on these motifs including K18E, K18Q, H107Y and N252D (CA-II); N86K, R219C, R219S and V234I (CA-IV); and E109D, G162R and R237Q (CA-VIII). As there were no x-ray crystal structures of the variant proteins, homology modelling was performed to calculate the protein structures for characterisation. In CA-VIII, the substitution of Ser for Pro at position 100 (variant S100P) resulted in destruction of the β-sheet that the SNV was located on. Little is known about the mechanism of interaction between CA-VIII and ITPR1, and residues involved. SiteMap and CPORT were used to identify binding site amino for CA-VIII and results identified 38 potential residues. Traditional FFs are incapable of performing MD simulations of metalloproteins. The AMBER ff14SB FF was extended and Zn2+ FF parameters calculated to add support for metalloprotein MD simulations. In the protein, Zn2+ was noted to have a charge less than +1. Variant effects on protein structure were then investigated using MD simulations. Root mean square deviation (RMSD) and radius of gyration (Rg) results indicated subtle SNV effects to the variant global structure in CA-II and CA-IV. However, with regards to CA-VIII RMSD analysis highlighted that variant presence was associated with increases to the structural rigidity of the protein. Principal component analysis (PCA) in conjunction with free energy analysis was performed to observe variant effects on protein conformational sampling in 3D space. The binding of BCT to CA-II induced greater protein conformational sampling and was associated with higher free energy. In CA-IV and CA-VIII PCA analysis revealed key differences in the mechanism of action of pathogenic and benign SNVs. In CA-IV, wild-type (WT) and benign variant protein structures clustered into single low energy well hinting at the presence of more stable structures. Pathogenic variants were associated with higher free energy and proteins sampled more conformations without settling into a low energy well. PCA analysis of CA-VIII indicated the opposite to CA-IV. Pathogenic variants were clustered into low energy wells, while the WT and benign variants showed greater conformational sampling. Dynamic cross correlation (DCC) analysis was performed using the MD-TASK suite to determine variant effects on residue movement. CA-II WT protein revealed that BCT and CO2 were associated with anti-correlated and correlated residue movement, highlighting at opposite mechanisms. In CA-IV and CA-VIII variant presence resulted in a change to residue correlation compared to the WT proteins. DRN analysis was performed to investigate SNV effects of residue accessibility and communication. Results demonstrated that SNVs are associated with allosteric effects on the CA protein structures, and effects are located on the stability assisting residues of the aromatic clusters and the active site of the proteins. CA-II studies discovered that Glu117 is the most important residue for communication, and variant presence results in a decrease to the usage of the residue. This effect was greatest in the CA-II H107Y SNV, and suggests that variants could have an effect on Zn2+ dissociation from the active site. Decreases to the usage of Zn2+ coordinating residues were also noted. Where this occurred, compensatory increases to the usage of other primary and secondary coordination residues were observed, that could possibly assist with the maintenance of Zn2+ within the active site. The CA-IV variants R69H and R219C highlighted potentially similar pathogenic mechanisms, whereas N86K and N177K hinted at potentially similar benign mechanisms. Within CA-VIII, variant presence was associated with changes to the accessibility of the N-terminal binding site residues. The benign CA-VIII variants highlighted possible compensatory mechanisms, whereby as one group of N-terminal residues loses accessibility, there was an increase to the accessibility of other binding site residues to possibly balance the effect. Catalytically, the proton shuttle residue His64 in CA-II was found to occupy a novel conformation named the “faux in” that brought the imidazole group even closer to the Zn2+ compared to the “in” conformation. Overall, compared to traditional MD simulations the incorporation of DRN allowed more detailed investigations into the variant mechanisms of action. This highlights the importance of network analysis in the study of the effects of missense mutations on the structure and function of proteins. Investigations of diseases at the molecular level is essential in the identification of disease pathogenesis and assists with the development of specifically tailored and better treatment options especially in the cases of genetically associated rare diseases.
- Full Text:
- Date Issued: 2020
Metallophthalocyanines linked to metal nanoparticles and folic acid for use in photodynamic therapy of cancer and photoinactivation of bacterial microorganisms.
- Authors: Matlou, Gauta Gold
- Date: 2020
- Subjects: Cancer -- Photochemotherapy , Nanoparticles , Phthalocyanines , Anti-infective agents -- Therapeutic use , Photochemotherapy , Photochemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166540 , vital:41377
- Description: This thesis presents on the synthesis and characterization of novel asymmetric and symmetrical metallophthalocyanines (MPcs) substituted with carboxylic acid functional groups and centrally metallated with zinc and indium. The MPcs are further covalently linked to cysteine capped silver nanoparticles (cys-AgNPs), amino functionalized magnetic nanoparticles (AMNPs) and folic acid (FA) through an amide bond between the carboxylic group of MPcs and the amino group of FA, cys-AgNPs or AMNPs. The covalent linkage of MPcs to FA improved the water solubility of MPcs and allowed for singlet oxygen quantum yield determination in water. Asymmetric MPcs and their conjugates were found to have improved photochemical and photophysical properties compared to symmetrical MPcs and their conjugates. The heavy atom effect of AMNPs and AgNPs improved the triplet and singlet oxygen quantum yields of MPcs. MPcs and their conjugates (MPc-FA, MPc-AMNPs, MPc-AgNPs) were found to have lower in vitro dark cytotoxicity and higher photodynamic therapy (PDT) activity on MCF-7 breast cancer cells. The water soluble MPc-FA had better PDT activity when compared to MPc-AMNPs due to the active targeting of folic acid-folate binding on cancer cell surface. MPcs and MPc-AgNPs conjugates also showed excellent in vitro cytotoxicity on S. aureus under light irradiation compared to dark cytotoxicity. The photosensitizing properties of MPcs and their conjugates are demonstrated for the first time in this thesis, both on breast cancer cells (MCF-7) through photodynamic therapy and on microorganisms (S. aureus) through photodynamic antimicrobial chemotherapy.
- Full Text:
- Date Issued: 2020
- Authors: Matlou, Gauta Gold
- Date: 2020
- Subjects: Cancer -- Photochemotherapy , Nanoparticles , Phthalocyanines , Anti-infective agents -- Therapeutic use , Photochemotherapy , Photochemistry
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/166540 , vital:41377
- Description: This thesis presents on the synthesis and characterization of novel asymmetric and symmetrical metallophthalocyanines (MPcs) substituted with carboxylic acid functional groups and centrally metallated with zinc and indium. The MPcs are further covalently linked to cysteine capped silver nanoparticles (cys-AgNPs), amino functionalized magnetic nanoparticles (AMNPs) and folic acid (FA) through an amide bond between the carboxylic group of MPcs and the amino group of FA, cys-AgNPs or AMNPs. The covalent linkage of MPcs to FA improved the water solubility of MPcs and allowed for singlet oxygen quantum yield determination in water. Asymmetric MPcs and their conjugates were found to have improved photochemical and photophysical properties compared to symmetrical MPcs and their conjugates. The heavy atom effect of AMNPs and AgNPs improved the triplet and singlet oxygen quantum yields of MPcs. MPcs and their conjugates (MPc-FA, MPc-AMNPs, MPc-AgNPs) were found to have lower in vitro dark cytotoxicity and higher photodynamic therapy (PDT) activity on MCF-7 breast cancer cells. The water soluble MPc-FA had better PDT activity when compared to MPc-AMNPs due to the active targeting of folic acid-folate binding on cancer cell surface. MPcs and MPc-AgNPs conjugates also showed excellent in vitro cytotoxicity on S. aureus under light irradiation compared to dark cytotoxicity. The photosensitizing properties of MPcs and their conjugates are demonstrated for the first time in this thesis, both on breast cancer cells (MCF-7) through photodynamic therapy and on microorganisms (S. aureus) through photodynamic antimicrobial chemotherapy.
- Full Text:
- Date Issued: 2020
Microbial fuel cells for remediation of metal rich wastewater coupled with bioelectricity generation
- Authors: Mshoperi, Edith
- Date: 2020
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/124112 , vital:35540
- Description: Expected release date-April 2022
- Full Text: false
- Date Issued: 2020
Microbial fuel cells for remediation of metal rich wastewater coupled with bioelectricity generation
- Authors: Mshoperi, Edith
- Date: 2020
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/124112 , vital:35540
- Description: Expected release date-April 2022
- Full Text: false
- Date Issued: 2020
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
Negotiating family planning messages among Malawian men: A case study of vasectomy messages aimed at men in the Dedza and Karonga districts of Malawi
- Authors: Ntaba, Jolly Maxwell
- Date: 2020
- Subjects: Social marketing -- Malawi , Vasectomy -- Social aspects -- Malawi , Malawians -- Attitudes , Men -- Malawi -- Attitudes , Men -- Conduct of life -- Malawi , Men -- Sexual behavior -- Malawi , Masculinity -- Malawi , Reproductive health in mass media -- Malawi , Reproductive health services -- Malawi
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167200 , vital:41446
- Description: Since the 1990s, vasectomy, the principal non-barrier method of contraception offered to men, has been vigorously promoted in Malawi, as a safe, effective and inexpensive form of birth control. Despite this marketing, the method has been chosen by only an estimated 0.01% of men in Malawi. This compares to about 11% of contraceptive using Malawian women, who have opted for tubal ligation, a more expensive and hazardous surgical procedure. Previous studies into this low uptake of vasectomy among men in Malawi, and other studies that have explored why no African country currently has a vasectomy rate of more than 1% of men, implicate cultural beliefs and traditional social practices among the key barriers to the diffusion of this particular innovation i.e. this method of contraception. Campaigns share new information in the hope that they will shift their audiences’ knowledge, and lead to changes in attitudes and practices, including the uptake of vasectomy. Social Marketing campaigns, even when they set out to explicitly accommodate these beliefs and challenge particular practices in order to promote various methods of contraception, are often inadequately conceived and sometimes poorly executed. Drawing on well-established theoretical perspectives developed by Cultural Studies scholars, including Reception Analysis and Thematic Analysis, this study investigates how men in two purposively selected districts of Karonga and Dedza in Malawi, interpret Social Marketing messages encouraging them to undergo vasectomies. The study examines key media texts and the nature of the involvement of a group of peer educators, dubbed ‘male champions’ in a 2017-2018 campaign by one of the leading Malawian providers of family planning services, the NGO Banja La Mtsogolo (BLM), to promote vasectomy. This is a purely qualitative case study that seeks to understand why these often-well-resourced campaigns have so little impact on the behaviour change they hope to inspire. Through individual interviews with the campaign’s designers, implementers, peer educators, focus group discussions with the campaign’s audiences, a close reading of texts used in the campaign, and observation, this study explores the circuits of communication and culture, through mechanisms of resonance, disconnection and even cognitive dissonance between the ‘encoders’ of the family planning messages and the decoders i.e. the intended audiences of the campaign. The study argues that as a result of several ‘modernist’ assumptions and outlooks, the campaign was unable to fully grasp the complex and contextually nuanced socio-cultural practices that factor into consideration of the campaign’s messages and the non-adoption of the proposed vasectomy method. The study further reveals, as many other studies have also observed, that the interpretation of the text promoting vasectomy is a complex process that is significantly shaped by the worldviews and lived experiences of the audiences. These views, as this study explores, are often complex and contradictory, interfacing aspirations of modernity with deeply held ‘traditional’ beliefs and practices. Although the campaigns are effective at transferring knowledge – it finds most targeted men have a relatively good understanding of the method and its efficacy – their prevailing socio-cultural attitudes and dispositions provide a strong countervailing discourse to the preferred reading of the campaign messages. This discourse exhorts having children, or the capacity to have children, even after a man has had several before, in current or previous marriages, or even in old age, as desirable and ‘rational’. The study therefore proposes, arising out of this detailed ethnographic research, a revised approach that argues that several social and cultural ‘vectors’ or ‘spheres of influence' need to be considered in new ways, in order to develop meaningful interventions in the promotion of vasectomy. This includes specific strategies to understand and challenge: 1. The enduring power of social stigma and scorn, and the notion of social shame. 2. The deep interplay between fertility and having children to notions of marriage, even in second or third marriages, and the interplay with perceptions of economic ‘value’ of children in the domestic political economy of marriage. 3. The embedded nature of provable fertility to notions of manhood. 4. The complex and nuanced involvement, at many levels, of broader social/family structures/personages in ‘personal’ decisions. 5. Forms of ‘hyperbolic discounting’, i.e. the calculating of precarious futures in various scenarios and its impact on current shorter-term calculations and gratifications. 6. Unusually high rates of infidelity in marriage, and seemingly low levels of trust in many partnerships. 7. The key role of interpersonal communication, i.e. the face-to-face elements of what are usually media-centric Social Marketing campaigns. The study recommends a more layered and nuanced approach to the promotion of vasectomy, propelled by a deeper understanding of these kinds of contexts and the interpretive power of the intended audience, as well as more nuanced segmentation of audiences, and more judicious use of peer-educators to support and deepen the mass media components of these communication campaigns.
- Full Text:
- Date Issued: 2020
- Authors: Ntaba, Jolly Maxwell
- Date: 2020
- Subjects: Social marketing -- Malawi , Vasectomy -- Social aspects -- Malawi , Malawians -- Attitudes , Men -- Malawi -- Attitudes , Men -- Conduct of life -- Malawi , Men -- Sexual behavior -- Malawi , Masculinity -- Malawi , Reproductive health in mass media -- Malawi , Reproductive health services -- Malawi
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167200 , vital:41446
- Description: Since the 1990s, vasectomy, the principal non-barrier method of contraception offered to men, has been vigorously promoted in Malawi, as a safe, effective and inexpensive form of birth control. Despite this marketing, the method has been chosen by only an estimated 0.01% of men in Malawi. This compares to about 11% of contraceptive using Malawian women, who have opted for tubal ligation, a more expensive and hazardous surgical procedure. Previous studies into this low uptake of vasectomy among men in Malawi, and other studies that have explored why no African country currently has a vasectomy rate of more than 1% of men, implicate cultural beliefs and traditional social practices among the key barriers to the diffusion of this particular innovation i.e. this method of contraception. Campaigns share new information in the hope that they will shift their audiences’ knowledge, and lead to changes in attitudes and practices, including the uptake of vasectomy. Social Marketing campaigns, even when they set out to explicitly accommodate these beliefs and challenge particular practices in order to promote various methods of contraception, are often inadequately conceived and sometimes poorly executed. Drawing on well-established theoretical perspectives developed by Cultural Studies scholars, including Reception Analysis and Thematic Analysis, this study investigates how men in two purposively selected districts of Karonga and Dedza in Malawi, interpret Social Marketing messages encouraging them to undergo vasectomies. The study examines key media texts and the nature of the involvement of a group of peer educators, dubbed ‘male champions’ in a 2017-2018 campaign by one of the leading Malawian providers of family planning services, the NGO Banja La Mtsogolo (BLM), to promote vasectomy. This is a purely qualitative case study that seeks to understand why these often-well-resourced campaigns have so little impact on the behaviour change they hope to inspire. Through individual interviews with the campaign’s designers, implementers, peer educators, focus group discussions with the campaign’s audiences, a close reading of texts used in the campaign, and observation, this study explores the circuits of communication and culture, through mechanisms of resonance, disconnection and even cognitive dissonance between the ‘encoders’ of the family planning messages and the decoders i.e. the intended audiences of the campaign. The study argues that as a result of several ‘modernist’ assumptions and outlooks, the campaign was unable to fully grasp the complex and contextually nuanced socio-cultural practices that factor into consideration of the campaign’s messages and the non-adoption of the proposed vasectomy method. The study further reveals, as many other studies have also observed, that the interpretation of the text promoting vasectomy is a complex process that is significantly shaped by the worldviews and lived experiences of the audiences. These views, as this study explores, are often complex and contradictory, interfacing aspirations of modernity with deeply held ‘traditional’ beliefs and practices. Although the campaigns are effective at transferring knowledge – it finds most targeted men have a relatively good understanding of the method and its efficacy – their prevailing socio-cultural attitudes and dispositions provide a strong countervailing discourse to the preferred reading of the campaign messages. This discourse exhorts having children, or the capacity to have children, even after a man has had several before, in current or previous marriages, or even in old age, as desirable and ‘rational’. The study therefore proposes, arising out of this detailed ethnographic research, a revised approach that argues that several social and cultural ‘vectors’ or ‘spheres of influence' need to be considered in new ways, in order to develop meaningful interventions in the promotion of vasectomy. This includes specific strategies to understand and challenge: 1. The enduring power of social stigma and scorn, and the notion of social shame. 2. The deep interplay between fertility and having children to notions of marriage, even in second or third marriages, and the interplay with perceptions of economic ‘value’ of children in the domestic political economy of marriage. 3. The embedded nature of provable fertility to notions of manhood. 4. The complex and nuanced involvement, at many levels, of broader social/family structures/personages in ‘personal’ decisions. 5. Forms of ‘hyperbolic discounting’, i.e. the calculating of precarious futures in various scenarios and its impact on current shorter-term calculations and gratifications. 6. Unusually high rates of infidelity in marriage, and seemingly low levels of trust in many partnerships. 7. The key role of interpersonal communication, i.e. the face-to-face elements of what are usually media-centric Social Marketing campaigns. The study recommends a more layered and nuanced approach to the promotion of vasectomy, propelled by a deeper understanding of these kinds of contexts and the interpretive power of the intended audience, as well as more nuanced segmentation of audiences, and more judicious use of peer-educators to support and deepen the mass media components of these communication campaigns.
- Full Text:
- Date Issued: 2020
NFComms: A synchronous communication framework for the CPU-NFP heterogeneous system
- Authors: Pennefather, Sean
- Date: 2020
- Subjects: Network processors , Computer programming , Parallel processing (Electronic computers) , Netronome
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/144181 , vital:38318
- Description: This work explores the viability of using a Network Flow Processor (NFP), developed by Netronome, as a coprocessor for the construction of a CPU-NFP heterogeneous platform in the domain of general processing. When considering heterogeneous platforms involving architectures like the NFP, the communication framework provided is typically represented as virtual network interfaces and is thus not suitable for generic communication. To enable a CPU-NFP heterogeneous platform for use in the domain of general computing, a suitable generic communication framework is required. A feasibility study for a suitable communication medium between the two candidate architectures showed that a generic framework that conforms to the mechanisms dictated by Communicating Sequential Processes is achievable. The resulting NFComms framework, which facilitates inter- and intra-architecture communication through the use of synchronous message passing, supports up to 16 unidirectional channels and includes queuing mechanisms for transparently supporting concurrent streams exceeding the channel count. The framework has a minimum latency of between 15.5 μs and 18 μs per synchronous transaction and can sustain a peak throughput of up to 30 Gbit/s. The framework also supports a runtime for interacting with the Go programming language, allowing user-space processes to subscribe channels to the framework for interacting with processes executing on the NFP. The viability of utilising a heterogeneous CPU-NFP system for use in the domain of general and network computing was explored by introducing a set of problems or applications spanning general computing, and network processing. These were implemented on the heterogeneous architecture and benchmarked against equivalent CPU-only and CPU/GPU solutions. The results recorded were used to form an opinion on the viability of using an NFP for general processing. It is the author’s opinion that, beyond very specific use cases, it appears that the NFP-400 is not currently a viable solution as a coprocessor in the field of general computing. This does not mean that the proposed framework or the concept of a heterogeneous CPU-NFP system should be discarded as such a system does have acceptable use in the fields of network and stream processing. Additionally, when comparing the recorded limitations to those seen during the early stages of general purpose GPU development, it is clear that general processing on the NFP is currently in a similar state.
- Full Text:
- Date Issued: 2020
- Authors: Pennefather, Sean
- Date: 2020
- Subjects: Network processors , Computer programming , Parallel processing (Electronic computers) , Netronome
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/144181 , vital:38318
- Description: This work explores the viability of using a Network Flow Processor (NFP), developed by Netronome, as a coprocessor for the construction of a CPU-NFP heterogeneous platform in the domain of general processing. When considering heterogeneous platforms involving architectures like the NFP, the communication framework provided is typically represented as virtual network interfaces and is thus not suitable for generic communication. To enable a CPU-NFP heterogeneous platform for use in the domain of general computing, a suitable generic communication framework is required. A feasibility study for a suitable communication medium between the two candidate architectures showed that a generic framework that conforms to the mechanisms dictated by Communicating Sequential Processes is achievable. The resulting NFComms framework, which facilitates inter- and intra-architecture communication through the use of synchronous message passing, supports up to 16 unidirectional channels and includes queuing mechanisms for transparently supporting concurrent streams exceeding the channel count. The framework has a minimum latency of between 15.5 μs and 18 μs per synchronous transaction and can sustain a peak throughput of up to 30 Gbit/s. The framework also supports a runtime for interacting with the Go programming language, allowing user-space processes to subscribe channels to the framework for interacting with processes executing on the NFP. The viability of utilising a heterogeneous CPU-NFP system for use in the domain of general and network computing was explored by introducing a set of problems or applications spanning general computing, and network processing. These were implemented on the heterogeneous architecture and benchmarked against equivalent CPU-only and CPU/GPU solutions. The results recorded were used to form an opinion on the viability of using an NFP for general processing. It is the author’s opinion that, beyond very specific use cases, it appears that the NFP-400 is not currently a viable solution as a coprocessor in the field of general computing. This does not mean that the proposed framework or the concept of a heterogeneous CPU-NFP system should be discarded as such a system does have acceptable use in the fields of network and stream processing. Additionally, when comparing the recorded limitations to those seen during the early stages of general purpose GPU development, it is clear that general processing on the NFP is currently in a similar state.
- 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
Non-marital fertility in South Africa: trends, determinants and implications
- Authors: Kara, Reesha
- Date: 2020
- Subjects: Fertility, Human -- South Africa , Child rearing -- South Africa , Parenting -- South Africa , Motherhood -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/165620 , vital:41264
- Description: Background: Non-martial fertility is traditionally associated with teenage pregnancy however international and South African literature has detailed increases in the number of adult women who are having children outside of a marriage. South African literature on non-marital fertility is sparse as it lacks a national overview of the trends and determinants of non-marital fertility among women aged 30 and older. The aim of this study was to present a national overview of non-marital fertility among women aged 30 and older. South African’s attitudes to and opinions of non-marital fertility were also investigated, and the lived realities of older mothers were explored. Methods: A mixed-methods research design was employed where the General Household Survey, National Income Dynamics Study and the South African Social Attitudes Survey were the main data sources. Using these data sets, descriptive and inferential statistics were computed using Stata. Using purposive and snowball sampling, four never-married older mothers (NMOMs) from KwaZulu-Natal (Durban) were identified as research participants. The in-depth life histories of these women were collected through face-to- face semi-structured interviews. Results: The results show an 18.43% increase in never-married mothers aged 15- 49 between 2002 and 2017 and interestingly, this increase is not necessarily driven by older mothers (30-49). NMOMs belonged to households with a lower average per capita total monthly household income (R1873.91) compared to all mothers aged 30-49 (R3428.76). NMOMs were also more likely to live in female-headed households (89.52%), to be household heads (64.22%) and to live in traditional areas (35.72%). Between 2002 and 2017, there was a 76.76% increase in mothers (aged 30-49) who were never married and a 7.74% decrease in those who were married, indicating a change in the marital profile of mothers. Despite this national increase in non-marital fertility, South African’s believe that premarital sexual activity is wrong, and that childbearing should take place within a marriage. Similar sentiments were echoed in the in-depth life histories as being the sole breadwinner and primary caregiver, the research participants experienced challenges as single mothers. Conclusion and recommendations: The study has found that there has been an increase in non-marital fertility in South Africa between 2002 and 2017 and that there is an economic element to non-marital fertility in the country. Additional research into non-marital fertility at a national level is recommended with a focus on all women aged 15-49.
- Full Text:
- Date Issued: 2020
- Authors: Kara, Reesha
- Date: 2020
- Subjects: Fertility, Human -- South Africa , Child rearing -- South Africa , Parenting -- South Africa , Motherhood -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/165620 , vital:41264
- Description: Background: Non-martial fertility is traditionally associated with teenage pregnancy however international and South African literature has detailed increases in the number of adult women who are having children outside of a marriage. South African literature on non-marital fertility is sparse as it lacks a national overview of the trends and determinants of non-marital fertility among women aged 30 and older. The aim of this study was to present a national overview of non-marital fertility among women aged 30 and older. South African’s attitudes to and opinions of non-marital fertility were also investigated, and the lived realities of older mothers were explored. Methods: A mixed-methods research design was employed where the General Household Survey, National Income Dynamics Study and the South African Social Attitudes Survey were the main data sources. Using these data sets, descriptive and inferential statistics were computed using Stata. Using purposive and snowball sampling, four never-married older mothers (NMOMs) from KwaZulu-Natal (Durban) were identified as research participants. The in-depth life histories of these women were collected through face-to- face semi-structured interviews. Results: The results show an 18.43% increase in never-married mothers aged 15- 49 between 2002 and 2017 and interestingly, this increase is not necessarily driven by older mothers (30-49). NMOMs belonged to households with a lower average per capita total monthly household income (R1873.91) compared to all mothers aged 30-49 (R3428.76). NMOMs were also more likely to live in female-headed households (89.52%), to be household heads (64.22%) and to live in traditional areas (35.72%). Between 2002 and 2017, there was a 76.76% increase in mothers (aged 30-49) who were never married and a 7.74% decrease in those who were married, indicating a change in the marital profile of mothers. Despite this national increase in non-marital fertility, South African’s believe that premarital sexual activity is wrong, and that childbearing should take place within a marriage. Similar sentiments were echoed in the in-depth life histories as being the sole breadwinner and primary caregiver, the research participants experienced challenges as single mothers. Conclusion and recommendations: The study has found that there has been an increase in non-marital fertility in South Africa between 2002 and 2017 and that there is an economic element to non-marital fertility in the country. Additional research into non-marital fertility at a national level is recommended with a focus on all women aged 15-49.
- Full Text:
- Date Issued: 2020
Not Yet Uhuru! Attuning to, re-imagining and regenerating transgressive decolonial pedagogical praxis across times Khapa(ring) the rising cultures of change drivers in contemporary South Africa
- Authors: Kulundu-Bolus, Injairu
- Date: 2020
- Subjects: Not Yet Uhuru (Arts Project) , Anti-imperialist movements -- South Africa , Education -- Social aspects -- South Africa , Social change -- South Africa , Education -- Philosophy -- South Africa , Arts and society -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/166081 , vital:41327 , 10.21504/10962/166081
- Description: The “Not yet Uhuru!” project positions itself as emancipatory African research in motion. It is a regenerative project that responds to the concern that whilst dominant discourses can articulate what African states, societies and economies are not, we still know very little about what they actually are. This is a particularly important gap in how research on Africa is conceptualised, especially as it pertains to apprehending the futures that the majority of young people on the continent are instinctively leading themselves to (Mbembe, 2001, p.9). The project seeks to forgo youth development strategies that act as a form of containment by prescribing normative aspects of citizenship on young leaders in ways that stifle the transgressive impulses they have reason to value (Kelley in Tuck and Yang, 2014, p.89). The study traces rising cultures in transgressive decolonial pedagogical praxis across times, as a way of “khapa(ring)” or accompanying the contemporary questions that Change Drivers in South Africa hold at the edge of their praxis. The study co-conspired with 21 Change Drivers in South Africa who were interested in regenerating and re-imagining what transgressive decolonial praxis could be in these times based on their experiences and learnings. Residential art-based workshops that explored each co-conspirator’s offerings on the subject were distilled through the medium of film. These in turn were analysed using an “ethics of attunement” that produced songs as a reflexive pedagogical tool (Lispari, 2014, p.176). Sharing the resonate echoes of their praxis through song created another iterative reflection on their praxis two years after their initial offerings. As a way of weaving together the findings with a historical perspective, the resonant praxis of Change Drivers was put into conversation with three unconventional reviews that trace impulses around transgressive decolonial pedagogical praxis through fictional texts, political theory, poetry and intergenerational analysis, in order to surface resonant themes in praxis that echo across different times in history. This methodology sought to engage the question of the archive in pluriversal ways that appealed to different sensibilities, including the imaginative and hermeneutical, the traditionally analytical as well as the gifts of the lyrical and the erotic as different conceptual threads needed to resource the study. The reviews additionally spanned periods in the history of the continent that hold questions around precolonial and nascent colonial encounters, efforts to transgress within the liberatory movements and the intergenerational transmissions embedded in women and queer people’s struggles. The themes that coalesced across times were leveraged into capsules of rising cultures that form an experimental nexus for the practice of transgressive decolonial pedagogical praxis that is already underway. These rising cultures were conceptualised as meditations on what it means to live into a vision of home built on the explorations of a paradigm of peace, humanness, pluriversality and decolonial love for those like and unlike us that strive for freedom on this continent (Dlala, 2017, p.52; Ndlovu- Gatsheni, 2013, p.142; Gqola, 2017, pp.197, 199). The rising ultures were reconciled through the creation of a litany that chronicles different refrains in transgressive decolonial pedagogical praxis in contemporary times. The litany is a tool that charts particular experiences that are surfacing as symptomatic. It seeks to generously surface the contradictions that we are collectively starting to see past, whilst acknowledging the tensions that we need to straddle, integrate and navigate towards greater synthesis. The litany is an honest way of acknowledging the glimpses gained of who we are in this present moment, while we continually challenge ourselves to open up to questions about what it means to grapple towards decolonial futures. This stance has influenced my role as an educator to unconditionally embrace movements that already underway, and reflect these back to those that I am conspiring with in ways that promote an ethic of care, solidarity and critical engagement. The study celebrates what is possible when we do not theorise ourselves away from the questions embedded in our current praxis. This is an ethic that chooses to stay close to the phenomena arriving at present, whilst acknowledging the historical experiences that echo it as a collective pulse for meaningful experimentation and praxis. The study believes by being faithful to ways of amplifying, integrating and reflecting what has been emerging for us over time, we build our capacity to better respond with an ethic centred on transgressive decolonial pedagogical praxis. This is the kind of accompaniment and care that Change Drivers across the continent deserve as they make the way towards a future worthy of their longing (Rushdie, 1999).
- Full Text:
- Date Issued: 2020
- Authors: Kulundu-Bolus, Injairu
- Date: 2020
- Subjects: Not Yet Uhuru (Arts Project) , Anti-imperialist movements -- South Africa , Education -- Social aspects -- South Africa , Social change -- South Africa , Education -- Philosophy -- South Africa , Arts and society -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/166081 , vital:41327 , 10.21504/10962/166081
- Description: The “Not yet Uhuru!” project positions itself as emancipatory African research in motion. It is a regenerative project that responds to the concern that whilst dominant discourses can articulate what African states, societies and economies are not, we still know very little about what they actually are. This is a particularly important gap in how research on Africa is conceptualised, especially as it pertains to apprehending the futures that the majority of young people on the continent are instinctively leading themselves to (Mbembe, 2001, p.9). The project seeks to forgo youth development strategies that act as a form of containment by prescribing normative aspects of citizenship on young leaders in ways that stifle the transgressive impulses they have reason to value (Kelley in Tuck and Yang, 2014, p.89). The study traces rising cultures in transgressive decolonial pedagogical praxis across times, as a way of “khapa(ring)” or accompanying the contemporary questions that Change Drivers in South Africa hold at the edge of their praxis. The study co-conspired with 21 Change Drivers in South Africa who were interested in regenerating and re-imagining what transgressive decolonial praxis could be in these times based on their experiences and learnings. Residential art-based workshops that explored each co-conspirator’s offerings on the subject were distilled through the medium of film. These in turn were analysed using an “ethics of attunement” that produced songs as a reflexive pedagogical tool (Lispari, 2014, p.176). Sharing the resonate echoes of their praxis through song created another iterative reflection on their praxis two years after their initial offerings. As a way of weaving together the findings with a historical perspective, the resonant praxis of Change Drivers was put into conversation with three unconventional reviews that trace impulses around transgressive decolonial pedagogical praxis through fictional texts, political theory, poetry and intergenerational analysis, in order to surface resonant themes in praxis that echo across different times in history. This methodology sought to engage the question of the archive in pluriversal ways that appealed to different sensibilities, including the imaginative and hermeneutical, the traditionally analytical as well as the gifts of the lyrical and the erotic as different conceptual threads needed to resource the study. The reviews additionally spanned periods in the history of the continent that hold questions around precolonial and nascent colonial encounters, efforts to transgress within the liberatory movements and the intergenerational transmissions embedded in women and queer people’s struggles. The themes that coalesced across times were leveraged into capsules of rising cultures that form an experimental nexus for the practice of transgressive decolonial pedagogical praxis that is already underway. These rising cultures were conceptualised as meditations on what it means to live into a vision of home built on the explorations of a paradigm of peace, humanness, pluriversality and decolonial love for those like and unlike us that strive for freedom on this continent (Dlala, 2017, p.52; Ndlovu- Gatsheni, 2013, p.142; Gqola, 2017, pp.197, 199). The rising ultures were reconciled through the creation of a litany that chronicles different refrains in transgressive decolonial pedagogical praxis in contemporary times. The litany is a tool that charts particular experiences that are surfacing as symptomatic. It seeks to generously surface the contradictions that we are collectively starting to see past, whilst acknowledging the tensions that we need to straddle, integrate and navigate towards greater synthesis. The litany is an honest way of acknowledging the glimpses gained of who we are in this present moment, while we continually challenge ourselves to open up to questions about what it means to grapple towards decolonial futures. This stance has influenced my role as an educator to unconditionally embrace movements that already underway, and reflect these back to those that I am conspiring with in ways that promote an ethic of care, solidarity and critical engagement. The study celebrates what is possible when we do not theorise ourselves away from the questions embedded in our current praxis. This is an ethic that chooses to stay close to the phenomena arriving at present, whilst acknowledging the historical experiences that echo it as a collective pulse for meaningful experimentation and praxis. The study believes by being faithful to ways of amplifying, integrating and reflecting what has been emerging for us over time, we build our capacity to better respond with an ethic centred on transgressive decolonial pedagogical praxis. This is the kind of accompaniment and care that Change Drivers across the continent deserve as they make the way towards a future worthy of their longing (Rushdie, 1999).
- 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