Developing and testing the congruency of selected biological indicators and an existing tool designed to assess wetland health in agricultural settings in the KZN Midlands
- Authors: Kubheka, Patrick Skhumbuzo
- Date: 2018
- Subjects: Wetland conservation -- South Africa -- KwaZulu-Natal , Wetland management -- South Africa -- KwaZulu-Natal , Wetland ecology -- South Africa -- KwaZulu-Natal , Ecosystem services -- South Africa -- KwaZulu-Natal , Environmental monitoring -- South Africa -- KwaZulu-Natal , Water quality biological assessment -- South Africa -- KwaZulu-Natal
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/58310 , vital:27211
- Description: Despite the fact that wetlands have been understood to be important for a wide range of ecosystem services, wetlands continue to be degraded globally. There has been a growing need to develop biomonitoring tools that reflect the present ecological state of wetlands, but very few attempts have been made in South Africa to achieve this, and those that have attempted this have generally achieved limited success. This study was conducted to develop and test the congruency of four selected biological indicators (dragonflies, frogs, macroinveterbrates and plants) in relation to the assessment of present ecological state using an existing method in South Africa, "WET-Health". WET-Health assessments rely primarily on transformations to a wetland that result from human impacts in both the catchment and the wetland itself. Using the tool, a health score is obtained that is consistent with the Department of Water Affairs (DWA) current "present ecological state” as applied to river health assessment. The study was conducted in agricultural settings of the Midlands of KwaZulu-Natal based on 13 wetlands. The selected wetlands were scored using WET - Health and grouped in four different ecological condition classes (A, B, C and D). Physical characteristics (wetland area, mean depth), biological characteristics (species cover/abundance, presence and species richness), and chemical characteristics (ammonia, pH, sulphate, nitrogen and phosphate) were also recorded in the selected wetlands. Nineteen different species of dragonfly were recorded in this study. The study demonstrated that dragonflies are a promising bioindicator of wetland present ecological state as the dragonfly index was found to be closely correlated with WET- Health scores. Open water bodies within the selected wetlands were the focus of dragonfly sampling, as male dragonflies are territorial and they will patrol or be found around this habitat. Emergent vegetation dominated by sedges formed the focus of macroinvertebrate sampling in this study because greater numbers of macroinvertebrate families were found in this biotope in comparison to open water areas with no emergent vegetation. A total of 47 macroinvertebrate families were recorded in this study, but SASS5 scores based on macroinvetebrates showed no correlation with WET-Health scores. A total of 10 different frog species were recorded in this study. All the species were common frog species found in most parts of the country. Frog species richness and occurrence showed no correlation with WET- Health scores. A total of twenty samples of two meter radius were measured per wetland and sampled for plant species and estimation of cover-abundance of each species per sample. Over 50 different plant species were recorded in this study, and both species accumulation and species richness showed a degree of correlation with WET-Health scores. All the wetlands in class A had generally higher species accumulation rate and species richness compared to the other wetland classes. In addition to testing the congruency of four selected biological indicators with WET- Health, water quality was measured in all the wetlands. Wetlands in class A were associated with improved water quality as the water passes through the wetland. However, wetlands in class C and D did not show consistently improved water quality between the apex and the toe of these wetlands. In some cases the water quality deteriorated as it passed through wetlands in these two classes.
- Full Text:
- Date Issued: 2018
- Authors: Kubheka, Patrick Skhumbuzo
- Date: 2018
- Subjects: Wetland conservation -- South Africa -- KwaZulu-Natal , Wetland management -- South Africa -- KwaZulu-Natal , Wetland ecology -- South Africa -- KwaZulu-Natal , Ecosystem services -- South Africa -- KwaZulu-Natal , Environmental monitoring -- South Africa -- KwaZulu-Natal , Water quality biological assessment -- South Africa -- KwaZulu-Natal
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/58310 , vital:27211
- Description: Despite the fact that wetlands have been understood to be important for a wide range of ecosystem services, wetlands continue to be degraded globally. There has been a growing need to develop biomonitoring tools that reflect the present ecological state of wetlands, but very few attempts have been made in South Africa to achieve this, and those that have attempted this have generally achieved limited success. This study was conducted to develop and test the congruency of four selected biological indicators (dragonflies, frogs, macroinveterbrates and plants) in relation to the assessment of present ecological state using an existing method in South Africa, "WET-Health". WET-Health assessments rely primarily on transformations to a wetland that result from human impacts in both the catchment and the wetland itself. Using the tool, a health score is obtained that is consistent with the Department of Water Affairs (DWA) current "present ecological state” as applied to river health assessment. The study was conducted in agricultural settings of the Midlands of KwaZulu-Natal based on 13 wetlands. The selected wetlands were scored using WET - Health and grouped in four different ecological condition classes (A, B, C and D). Physical characteristics (wetland area, mean depth), biological characteristics (species cover/abundance, presence and species richness), and chemical characteristics (ammonia, pH, sulphate, nitrogen and phosphate) were also recorded in the selected wetlands. Nineteen different species of dragonfly were recorded in this study. The study demonstrated that dragonflies are a promising bioindicator of wetland present ecological state as the dragonfly index was found to be closely correlated with WET- Health scores. Open water bodies within the selected wetlands were the focus of dragonfly sampling, as male dragonflies are territorial and they will patrol or be found around this habitat. Emergent vegetation dominated by sedges formed the focus of macroinvertebrate sampling in this study because greater numbers of macroinvertebrate families were found in this biotope in comparison to open water areas with no emergent vegetation. A total of 47 macroinvertebrate families were recorded in this study, but SASS5 scores based on macroinvetebrates showed no correlation with WET-Health scores. A total of 10 different frog species were recorded in this study. All the species were common frog species found in most parts of the country. Frog species richness and occurrence showed no correlation with WET- Health scores. A total of twenty samples of two meter radius were measured per wetland and sampled for plant species and estimation of cover-abundance of each species per sample. Over 50 different plant species were recorded in this study, and both species accumulation and species richness showed a degree of correlation with WET-Health scores. All the wetlands in class A had generally higher species accumulation rate and species richness compared to the other wetland classes. In addition to testing the congruency of four selected biological indicators with WET- Health, water quality was measured in all the wetlands. Wetlands in class A were associated with improved water quality as the water passes through the wetland. However, wetlands in class C and D did not show consistently improved water quality between the apex and the toe of these wetlands. In some cases the water quality deteriorated as it passed through wetlands in these two classes.
- Full Text:
- Date Issued: 2018
Developing leadership and learner voice: a formative intervention in a Learner Representative Council in a Namibian secondary school
- Authors: Haipa, Vistorina
- Date: 2018
- Subjects: School management and organization -- Namibia , Educational leadership -- Namibia , Education, Secondary -- Namibia , Student government -- Namibia , Student participation in administration -- Namibia , Student participation in administration -- Law and legislation -- Namibia , Cultural Historical Activity Theory
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/62188 , vital:28136
- Description: Learner participation in leadership in Namibian schools was legislated in 2001 through the Namibian Education Act, No. 16 of 2001. This has then become a requirement for all secondary schools to establish a Learner Representative Council (LRC). However, this legislation only gives mandates to schools with grade 8-12. Despite the impetus of having a LRC in secondary schools, learner leadership and voice remains limited, given that we are 26 years into our democracy. This awakened my interest to conduct a study aimed at developing leadership and voice within the LRC in a Namibian secondary school. Additionally, this study was conducted to contribute to filling the gap in literature of Cultural Historical Activity Theory (CHAT) studies in the field of Education Leadership and Management. In this critical case orientation, the LRC were the subjects and the object of the activity was voice and leadership development within the LRC. I investigated participants’ perspectives on LRC leadership opportunities that existed in the case study school as well as factors that enabled and constrained leadership and voice development within the LRC of Omukumo (pseudonym) Secondary School in the northern part of Namibia. My study adopted a formative intervention design, using qualitative methodologies such as document analysis, observation, interviews, questionnaires and Change Laboratory Workshops. This study was framed by the second generation of CHAT. CHAT in this study was used as a methodological and analytical tool to surface the contradictions. Additionally, data were analysed by means of constructing categories and themes. Five sets of findings emerged: (1) a lack of conceptual awareness of the construct ‘learner leadership’: learner leadership was understood in terms of the LRC, (2) LRC members were not really acknowledged as equal participants in the school decision-making due to unequal power relations between the teachers and the LRC members, (3) misinterpretation of LRC policy that speak about the establishment of learners club and inadequate LRC training hindered the development of voice and leadership within the LRC, (4) the overall leadership role assigned to the LRC was to oversee the adherence of the school rules, and last (5) learner leadership and voice was still developing in the case study school. My key recommendation based on the research findings is the need for on-going LRC training at regional level; a need for large scale comparative studies between two African countries (Namibia, & South Africa) on the topic of learner leadership development and last, a need for workshops to train teachers on the implementation of national policies in schools, in particular those that speak to issues of learner voice and leadership.
- Full Text:
- Date Issued: 2018
- Authors: Haipa, Vistorina
- Date: 2018
- Subjects: School management and organization -- Namibia , Educational leadership -- Namibia , Education, Secondary -- Namibia , Student government -- Namibia , Student participation in administration -- Namibia , Student participation in administration -- Law and legislation -- Namibia , Cultural Historical Activity Theory
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: http://hdl.handle.net/10962/62188 , vital:28136
- Description: Learner participation in leadership in Namibian schools was legislated in 2001 through the Namibian Education Act, No. 16 of 2001. This has then become a requirement for all secondary schools to establish a Learner Representative Council (LRC). However, this legislation only gives mandates to schools with grade 8-12. Despite the impetus of having a LRC in secondary schools, learner leadership and voice remains limited, given that we are 26 years into our democracy. This awakened my interest to conduct a study aimed at developing leadership and voice within the LRC in a Namibian secondary school. Additionally, this study was conducted to contribute to filling the gap in literature of Cultural Historical Activity Theory (CHAT) studies in the field of Education Leadership and Management. In this critical case orientation, the LRC were the subjects and the object of the activity was voice and leadership development within the LRC. I investigated participants’ perspectives on LRC leadership opportunities that existed in the case study school as well as factors that enabled and constrained leadership and voice development within the LRC of Omukumo (pseudonym) Secondary School in the northern part of Namibia. My study adopted a formative intervention design, using qualitative methodologies such as document analysis, observation, interviews, questionnaires and Change Laboratory Workshops. This study was framed by the second generation of CHAT. CHAT in this study was used as a methodological and analytical tool to surface the contradictions. Additionally, data were analysed by means of constructing categories and themes. Five sets of findings emerged: (1) a lack of conceptual awareness of the construct ‘learner leadership’: learner leadership was understood in terms of the LRC, (2) LRC members were not really acknowledged as equal participants in the school decision-making due to unequal power relations between the teachers and the LRC members, (3) misinterpretation of LRC policy that speak about the establishment of learners club and inadequate LRC training hindered the development of voice and leadership within the LRC, (4) the overall leadership role assigned to the LRC was to oversee the adherence of the school rules, and last (5) learner leadership and voice was still developing in the case study school. My key recommendation based on the research findings is the need for on-going LRC training at regional level; a need for large scale comparative studies between two African countries (Namibia, & South Africa) on the topic of learner leadership development and last, a need for workshops to train teachers on the implementation of national policies in schools, in particular those that speak to issues of learner voice and leadership.
- Full Text:
- Date Issued: 2018
Development and assessment of a smart thermosetting intranasal hydrogel for lamotrigine
- Authors: Melamane, Siyabonga
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62975 , vital:28349
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018
- Authors: Melamane, Siyabonga
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62975 , vital:28349
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018
Development and assessment of gastroretentive sustained release captopril micro-balloons
- Authors: Oridota, Omoyosola Omolola
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63491 , vital:28419
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018
- Authors: Oridota, Omoyosola Omolola
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63491 , vital:28419
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018
Development and evaluation of a web application employing artificial neural networks to facilitate the prediction of antiretroviral drug resistance in patients infected with HIV-1 subtype B
- Authors: Nabatanzi, Margaret
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63396 , vital:28406
- Description: Expected release date-April 2019
- Full Text:
- Date Issued: 2018
- Authors: Nabatanzi, Margaret
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63396 , vital:28406
- Description: Expected release date-April 2019
- Full Text:
- Date Issued: 2018
Development and optimisation of a novel Plasmodium falciparum Hsp90-Hop interaction assay
- Authors: Wambua, Lynn
- Date: 2018
- Subjects: Plasmodium falciparum , Molecular chaperones , Heat shock proteins , Protein-protein interactions , Antimalarials
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62626 , vital:28216
- Description: Protein-protein interactions are involved in a range of disease processes and thus have become the focus of many drug discovery programs. Widespread drug resistance to all currently used antimalarial drugs drives the search for alternative drug targets with novel mechanisms of action that offer new therapeutic options. Molecular chaperones such as heat shock proteins facilitate protein folding, play a role in protein trafficking and prevent protein misfolding in cells under stress. Heat shock protein 90 (Hsp90) is a well-studied chaperone that has been the focus of cancer drug development with moderate success. In Plasmodium falciparum (P. falciparum), heat shock proteins are thought to play a vital role in parasite survival of the physiologically diverse habitats of the parasite lifecycle and because Hsp90 is prominently expressed in P. falciparum, the chaperone is considered a potentially ideal drug target. Hsp90 function in cells is regulated by interactions with co-chaperones, which includes Heat shock protein 70-Heat shock protein 90 organising protein (Hop). As opposed to directly inhibiting Hsp90 activity, targeting Hsp90 interaction with Hop has recently been suggested as an alternative method of Hsp90 inhibition that has not been explored in P. falciparum. The aim of this research project was to demonstrate PfHsp90 and PfHop robustly interact in vitro and to facilitate high-throughput screening of PfHsp90-PfHop inhibitors by developing and optimising a novel plate capture Hsp90-Hop interaction assay. To establish the assay, the respective domains of the proteins that mediate Hsp90-Hop interaction were used (Hsp90 C- terminal domain and Hop TPR2A domain). The human Hsp90 C-terminal domain and glutathione-S-transferase (GST) coding sequences were cloned into pET-28a(+) and murine and P. falciparum TPR2A sequences into pGEX-4T-1 plasmids to enable expression of histidine-tagged and GST fusion proteins, respectively, in Escherichia coli. The P. falciparum Hsp90 C-terminal domain sequence cloned into pET-28a(+) was supplied by GenScript. The constructs were transformed into T7 Express lysYcompetent E. coli cells and subsequent small- scale expression studies showed the recombinant proteins were expressed in a soluble form allowing for subsequent protein purification. Purification of the recombinant proteins was achieved using nickel-NTA and glutathione affinity chromatography for the His-tagged (Hsp90 C-terminal domains and GST) and GST fusion proteins (TPR2A domains), respectively. The purified proteins were used to establish and optimise mammalian and P. falciparum Hsp90- Hop interaction assays on nickel-coated plates by immobilising the His-tagged C-terminal domains on the plates and detecting the binding of the GST-TPR2A domains using a colorimetric GST enzyme assay. Z’-factor values above 0.5 were observed for both assays indicating good separation between the protein interaction signals and negative control background signals, although relatively high background signals were observed for the mammalian interaction due to non-specific binding of murine TPR2A to the plate. Designed human and P. falciparum TPR peptides were observed to be effective inhibitors of the mammalian and P. falciparum interactions, demonstrating the assay’s ability to respond to inhibitor compounds. Comparison of assay performance using GST assay kit reagents and lab- prepared reagents showed the assay was more efficient using lab-prepared reagents, however, lower GST signals were observed when comparing assay performance using a custom prepared Ni-NTA plate to a purchased Ni-NTA plate. The Hsp90-Hop interaction assays were also performed using an alternative assay format in which the GST-TPR2A fusion proteins were immobilised on glutathione-coated plates and binding of the His-tagged C-terminal domains detected with a nickel-horseradish peroxidase (HRP) conjugate and a colorimetric HRP substrate. The assay showed higher interaction signals for the P. falciparum proteins but comparatively low signals for the mammalian proteins. Z’-factor values for the assay were above 0.8 for both protein sets, suggesting this assay format is superior to the GST assay. However, further optimisation of this assay format is required. This study demonstrated direct binding of PfHsp90-PfHop in vitro and established a novel and robust PfHsp90-PfHop interaction assay format that can be used in future screening campaigns.
- Full Text:
- Date Issued: 2018
- Authors: Wambua, Lynn
- Date: 2018
- Subjects: Plasmodium falciparum , Molecular chaperones , Heat shock proteins , Protein-protein interactions , Antimalarials
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62626 , vital:28216
- Description: Protein-protein interactions are involved in a range of disease processes and thus have become the focus of many drug discovery programs. Widespread drug resistance to all currently used antimalarial drugs drives the search for alternative drug targets with novel mechanisms of action that offer new therapeutic options. Molecular chaperones such as heat shock proteins facilitate protein folding, play a role in protein trafficking and prevent protein misfolding in cells under stress. Heat shock protein 90 (Hsp90) is a well-studied chaperone that has been the focus of cancer drug development with moderate success. In Plasmodium falciparum (P. falciparum), heat shock proteins are thought to play a vital role in parasite survival of the physiologically diverse habitats of the parasite lifecycle and because Hsp90 is prominently expressed in P. falciparum, the chaperone is considered a potentially ideal drug target. Hsp90 function in cells is regulated by interactions with co-chaperones, which includes Heat shock protein 70-Heat shock protein 90 organising protein (Hop). As opposed to directly inhibiting Hsp90 activity, targeting Hsp90 interaction with Hop has recently been suggested as an alternative method of Hsp90 inhibition that has not been explored in P. falciparum. The aim of this research project was to demonstrate PfHsp90 and PfHop robustly interact in vitro and to facilitate high-throughput screening of PfHsp90-PfHop inhibitors by developing and optimising a novel plate capture Hsp90-Hop interaction assay. To establish the assay, the respective domains of the proteins that mediate Hsp90-Hop interaction were used (Hsp90 C- terminal domain and Hop TPR2A domain). The human Hsp90 C-terminal domain and glutathione-S-transferase (GST) coding sequences were cloned into pET-28a(+) and murine and P. falciparum TPR2A sequences into pGEX-4T-1 plasmids to enable expression of histidine-tagged and GST fusion proteins, respectively, in Escherichia coli. The P. falciparum Hsp90 C-terminal domain sequence cloned into pET-28a(+) was supplied by GenScript. The constructs were transformed into T7 Express lysYcompetent E. coli cells and subsequent small- scale expression studies showed the recombinant proteins were expressed in a soluble form allowing for subsequent protein purification. Purification of the recombinant proteins was achieved using nickel-NTA and glutathione affinity chromatography for the His-tagged (Hsp90 C-terminal domains and GST) and GST fusion proteins (TPR2A domains), respectively. The purified proteins were used to establish and optimise mammalian and P. falciparum Hsp90- Hop interaction assays on nickel-coated plates by immobilising the His-tagged C-terminal domains on the plates and detecting the binding of the GST-TPR2A domains using a colorimetric GST enzyme assay. Z’-factor values above 0.5 were observed for both assays indicating good separation between the protein interaction signals and negative control background signals, although relatively high background signals were observed for the mammalian interaction due to non-specific binding of murine TPR2A to the plate. Designed human and P. falciparum TPR peptides were observed to be effective inhibitors of the mammalian and P. falciparum interactions, demonstrating the assay’s ability to respond to inhibitor compounds. Comparison of assay performance using GST assay kit reagents and lab- prepared reagents showed the assay was more efficient using lab-prepared reagents, however, lower GST signals were observed when comparing assay performance using a custom prepared Ni-NTA plate to a purchased Ni-NTA plate. The Hsp90-Hop interaction assays were also performed using an alternative assay format in which the GST-TPR2A fusion proteins were immobilised on glutathione-coated plates and binding of the His-tagged C-terminal domains detected with a nickel-horseradish peroxidase (HRP) conjugate and a colorimetric HRP substrate. The assay showed higher interaction signals for the P. falciparum proteins but comparatively low signals for the mammalian proteins. Z’-factor values for the assay were above 0.8 for both protein sets, suggesting this assay format is superior to the GST assay. However, further optimisation of this assay format is required. This study demonstrated direct binding of PfHsp90-PfHop in vitro and established a novel and robust PfHsp90-PfHop interaction assay format that can be used in future screening campaigns.
- Full Text:
- Date Issued: 2018
Development of a computational chemistry scheme for testing the utility of synthetic bacteriochlorin in dye-sensitized solar cells
- Authors: Kota, Ntsika
- Date: 2018
- Subjects: Dye-sensitized solar cells , Computational chemistry , Density functionals , Electronic excitation , Molecular orbitals , Oscillator strengths , Bacteriochlorin
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62327 , vital:28155
- Description: A computational chemistry scheme, based on density functional theory, was developed for in silico testing of a few bacteriochlorin properties relevant to dye-sensitized solar cells. These properties included electronic excitation wavelengths, molecular orbital energy levels, and oscillator strengths among others. Comparisons were made among four species, using computational proxies for electron injection quantum yield and photo-induced current production. The proxy measures for current production (frontier orbital energy level and short circuit current) made consistent, though qualitative, predictions about the ranking of the four dyes. The proxy measures for electron injection quantum yield (change in planar dipole moment and density of states) made less categorical predictions about the ranking. Overall, the scheme singled out one dye as the worst, but made no conclusive predictions about the relative ranking of the other three. There was insufficient data for comparison of the ranking predictions with experiment.
- Full Text:
- Date Issued: 2018
- Authors: Kota, Ntsika
- Date: 2018
- Subjects: Dye-sensitized solar cells , Computational chemistry , Density functionals , Electronic excitation , Molecular orbitals , Oscillator strengths , Bacteriochlorin
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62327 , vital:28155
- Description: A computational chemistry scheme, based on density functional theory, was developed for in silico testing of a few bacteriochlorin properties relevant to dye-sensitized solar cells. These properties included electronic excitation wavelengths, molecular orbital energy levels, and oscillator strengths among others. Comparisons were made among four species, using computational proxies for electron injection quantum yield and photo-induced current production. The proxy measures for current production (frontier orbital energy level and short circuit current) made consistent, though qualitative, predictions about the ranking of the four dyes. The proxy measures for electron injection quantum yield (change in planar dipole moment and density of states) made less categorical predictions about the ranking. Overall, the scheme singled out one dye as the worst, but made no conclusive predictions about the relative ranking of the other three. There was insufficient data for comparison of the ranking predictions with experiment.
- Full Text:
- Date Issued: 2018
Development of a low-cost bioprinting system for the fabrication of cell-laden sodium alginate hydrogels
- Authors: Honiball, John Robert
- Date: 2018
- Subjects: Regenerative medicine , Tissue engineering , Alginates , Colloids , Three-dimensional printing
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/59204 , vital:27470
- Description: Bioprinting is a rapidly expanding technology with the ability to fabricate in vitro 3D tissues in a layer-by-layer manner to ultimately produce a living tissue which physiologically resembles native in vivo tissue functionality. Unfortunately, large costs associated with commercially available bioprinters severely limit the amount of people/research groups with access to the technology. Here, we investigated the potential for modifying a commercially available RepRap Prusa iteration 3 (i3) three-dimensional (3D) printer, by replacing the traditional plastic-based print-head with various open-source syringe-housed microextrusion print-head units, such that deposition of composite bioinks consisting of cells, biopolymer scaffolds and/or biomolecules may be achieved at a relatively low cost. Using adipose-derived human mesenchymal stromal stem cells (ad-HMSC) induced for adipogenic differentiation, as well as human umbilical vein endothelial cells (HUVEC), the potential for fabricating vascularised adipose tissue was investigated. The non-toxic, inexpensive algal polysaccharide, sodium alginate, was used to test the printability of the system, as well as for investigating the functionality unmodified sodium alginate has for use as a potential bioink in adipose tissue engineering. Cell viability assays, namely WST-1 and fluorescein diacetate (FDA)/propidium iodide (PI) live/dead cell staining, revealed that ad-HMSC were viable after 7 days of culture. However, viability of HUVEC encapsulated hydrogels revealed significantly lower cell viability. Live/dead cell staining revealed that the modified printing system was able to print ad-HMSC/HUVEC co-cocultures with a large degree of cell viability after 1 day of culture. However, after 7 days of culture, the majority of cells were revealed to be dead. Furthermore, due to the lack of mechanical integrity possessed by alginate in a liquid-like state, printing sodium alginate hydrogels in air consistently resulted in deformation of printed constructs. The newly developed 3D printing technique termed freeform reversible embedding of suspended hydrogels (FRESH) was therefore investigated as a means for achieving 3D spatial control of printed hydrogels using the modified system. Printing cell-free sodium alginate hydrogels within gelatin sacrificial support baths allowed for fabricating constructs in a spatially defined manner. However, overprinting and swelling of alginate hydrogels negatively affected the overall printing accuracy. The present study aimed to pave the way for further system modifications and refinements, such that the ultimate goal of low-cost bioprinting may be achieved. Further optimisation of printing parameters, hydrogel characteristics and sterilisation techniques may allow for fabricating viable, physiologically relevant tissues using the modified system developed.
- Full Text:
- Date Issued: 2018
- Authors: Honiball, John Robert
- Date: 2018
- Subjects: Regenerative medicine , Tissue engineering , Alginates , Colloids , Three-dimensional printing
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/59204 , vital:27470
- Description: Bioprinting is a rapidly expanding technology with the ability to fabricate in vitro 3D tissues in a layer-by-layer manner to ultimately produce a living tissue which physiologically resembles native in vivo tissue functionality. Unfortunately, large costs associated with commercially available bioprinters severely limit the amount of people/research groups with access to the technology. Here, we investigated the potential for modifying a commercially available RepRap Prusa iteration 3 (i3) three-dimensional (3D) printer, by replacing the traditional plastic-based print-head with various open-source syringe-housed microextrusion print-head units, such that deposition of composite bioinks consisting of cells, biopolymer scaffolds and/or biomolecules may be achieved at a relatively low cost. Using adipose-derived human mesenchymal stromal stem cells (ad-HMSC) induced for adipogenic differentiation, as well as human umbilical vein endothelial cells (HUVEC), the potential for fabricating vascularised adipose tissue was investigated. The non-toxic, inexpensive algal polysaccharide, sodium alginate, was used to test the printability of the system, as well as for investigating the functionality unmodified sodium alginate has for use as a potential bioink in adipose tissue engineering. Cell viability assays, namely WST-1 and fluorescein diacetate (FDA)/propidium iodide (PI) live/dead cell staining, revealed that ad-HMSC were viable after 7 days of culture. However, viability of HUVEC encapsulated hydrogels revealed significantly lower cell viability. Live/dead cell staining revealed that the modified printing system was able to print ad-HMSC/HUVEC co-cocultures with a large degree of cell viability after 1 day of culture. However, after 7 days of culture, the majority of cells were revealed to be dead. Furthermore, due to the lack of mechanical integrity possessed by alginate in a liquid-like state, printing sodium alginate hydrogels in air consistently resulted in deformation of printed constructs. The newly developed 3D printing technique termed freeform reversible embedding of suspended hydrogels (FRESH) was therefore investigated as a means for achieving 3D spatial control of printed hydrogels using the modified system. Printing cell-free sodium alginate hydrogels within gelatin sacrificial support baths allowed for fabricating constructs in a spatially defined manner. However, overprinting and swelling of alginate hydrogels negatively affected the overall printing accuracy. The present study aimed to pave the way for further system modifications and refinements, such that the ultimate goal of low-cost bioprinting may be achieved. Further optimisation of printing parameters, hydrogel characteristics and sterilisation techniques may allow for fabricating viable, physiologically relevant tissues using the modified system developed.
- Full Text:
- Date Issued: 2018
Discontinuous gully erosion as a mechanism of wetland formation: a case study of the Kompanjiesdrif basin, Kromrivier, Eastern Cape, South Africa
- Authors: Lagesse, Juliette V
- Date: 2018
- Subjects: Arroyos -- South Africa -- Kromme River (Eastern Cape) , Arroyos -- Erosion -- South Africa -- Kromme River (Eastern Cape) , Climatic geomorphology -- South Africa -- Kromme River (Eastern Cape) , Sedimentation and deposition -- South Africa -- Kromme River (Eastern Cape) , Alluvial fans -- South Africa -- Kromme River (Eastern Cape) , Wetland ecology -- South Africa -- Kromme River (Eastern Cape) , Rhizophoraceae , Palmiet (Prionium serratum)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60540 , vital:27791
- Description: The Kompanjiesdrif basin is an unchannelled valley bottom palmiet wetland located near the headwaters of the Kromrivier in the Eastern Cape of South Africa. The wetland itself is underlain by Bokkeveld shales with the bordering mountain ranges comprising more resistant Table Mountain Group quarzitic sandstones. The valley is relatively planar and broad in form over a width of approximately 200 m. None of the existing controls that are considered to lead to valley widening and longitudinal slope reduction are immediately apparent. The basin lies on the Post Africa II erosion surface; with no evidence of a resistant lithology which might act as a local base level, limiting rates of vertical erosion and inducing lateral planing in upstream reaches via a meandering channel. The possible role of sagging of the basin due to long term deep chemical weathering of bedrock is discounted as the lithologies in the basin are sedimentary in origin and thus not susceptible to chemical weathering. The degree to which climate and sea level changes affected rates of incision and subsequent slope reduction is unclear, although their potential influence should be acknowledged. This study examined the geomorphic dynamics as discerned from the sedimentary record and morphology of the wetland basin, which provide a snapshot into the long-term processes which lowered the longitudinal slope and widened this valley. Coring within the wetland to depths of 1 - 3.3 m revealed that the sedimentary fill generally comprised an upward fining sequence, with sand or fine sand at the base, grading into silt and clay and organic material in the upper sections of cores. Occasional instances of multiple fine sand layers were observed in a few of the cores. An increase in the organic content of material from the north to the south side of the wetland and the occurrence of multiple thin layers of sand in the stratigraphy, highlighted the role of the northern tributary alluvial fans in influencing valley form. Sediment from north bank alluvial fans seem to periodically, partially impound the wetland basin. Surveyed transects across the wetland basin along with subsurface coring to the depth to refusal, illustrated a localised increase in longitudinal slope downstream of the nodes of tributary alluvial fan deposits, which impinge on the trunk stream basin. Coupled with the presence of deep, drowned, trench-like features (up to 8 m deep) beneath floating mats of palmiet, which were predominantly free of sedimentary fill and found opposite tributary alluvial fans; confirmed that the northern tributaries play a major role in the structure and geomorphic dynamics of the basin. The trench-like features appeared to be remnants of deep, narrow, discontinuous gullies. Dating of sediment from the base of these features (460-7040 BP) confirmed that they were formed prior to European settlement in the area. Therefore, it is suggested that the localised increase in longitudinal slope, caused by sediment deposition on the alluvial fans, transgresses a geomorphic threshold slope and that gully erosion is thus initiated. The process of repeated gully erosion leads to planing of bedrock and longitudinal slope reduction. Gully erosion forms an integral component of a cycle of deposition and incision referred to as “cut-and-fill”. During each iteration of the cycle of cutting and filling, gullies form in novel locations leading to gradual valley widening. Over geological time scales, the planing of bedrock and resultant valley widening creates a broad planar valley with a very low longitudinal slope; producing conditions suitable for unchannelled valley bottom wetland formation.
- Full Text:
- Date Issued: 2018
- Authors: Lagesse, Juliette V
- Date: 2018
- Subjects: Arroyos -- South Africa -- Kromme River (Eastern Cape) , Arroyos -- Erosion -- South Africa -- Kromme River (Eastern Cape) , Climatic geomorphology -- South Africa -- Kromme River (Eastern Cape) , Sedimentation and deposition -- South Africa -- Kromme River (Eastern Cape) , Alluvial fans -- South Africa -- Kromme River (Eastern Cape) , Wetland ecology -- South Africa -- Kromme River (Eastern Cape) , Rhizophoraceae , Palmiet (Prionium serratum)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60540 , vital:27791
- Description: The Kompanjiesdrif basin is an unchannelled valley bottom palmiet wetland located near the headwaters of the Kromrivier in the Eastern Cape of South Africa. The wetland itself is underlain by Bokkeveld shales with the bordering mountain ranges comprising more resistant Table Mountain Group quarzitic sandstones. The valley is relatively planar and broad in form over a width of approximately 200 m. None of the existing controls that are considered to lead to valley widening and longitudinal slope reduction are immediately apparent. The basin lies on the Post Africa II erosion surface; with no evidence of a resistant lithology which might act as a local base level, limiting rates of vertical erosion and inducing lateral planing in upstream reaches via a meandering channel. The possible role of sagging of the basin due to long term deep chemical weathering of bedrock is discounted as the lithologies in the basin are sedimentary in origin and thus not susceptible to chemical weathering. The degree to which climate and sea level changes affected rates of incision and subsequent slope reduction is unclear, although their potential influence should be acknowledged. This study examined the geomorphic dynamics as discerned from the sedimentary record and morphology of the wetland basin, which provide a snapshot into the long-term processes which lowered the longitudinal slope and widened this valley. Coring within the wetland to depths of 1 - 3.3 m revealed that the sedimentary fill generally comprised an upward fining sequence, with sand or fine sand at the base, grading into silt and clay and organic material in the upper sections of cores. Occasional instances of multiple fine sand layers were observed in a few of the cores. An increase in the organic content of material from the north to the south side of the wetland and the occurrence of multiple thin layers of sand in the stratigraphy, highlighted the role of the northern tributary alluvial fans in influencing valley form. Sediment from north bank alluvial fans seem to periodically, partially impound the wetland basin. Surveyed transects across the wetland basin along with subsurface coring to the depth to refusal, illustrated a localised increase in longitudinal slope downstream of the nodes of tributary alluvial fan deposits, which impinge on the trunk stream basin. Coupled with the presence of deep, drowned, trench-like features (up to 8 m deep) beneath floating mats of palmiet, which were predominantly free of sedimentary fill and found opposite tributary alluvial fans; confirmed that the northern tributaries play a major role in the structure and geomorphic dynamics of the basin. The trench-like features appeared to be remnants of deep, narrow, discontinuous gullies. Dating of sediment from the base of these features (460-7040 BP) confirmed that they were formed prior to European settlement in the area. Therefore, it is suggested that the localised increase in longitudinal slope, caused by sediment deposition on the alluvial fans, transgresses a geomorphic threshold slope and that gully erosion is thus initiated. The process of repeated gully erosion leads to planing of bedrock and longitudinal slope reduction. Gully erosion forms an integral component of a cycle of deposition and incision referred to as “cut-and-fill”. During each iteration of the cycle of cutting and filling, gullies form in novel locations leading to gradual valley widening. Over geological time scales, the planing of bedrock and resultant valley widening creates a broad planar valley with a very low longitudinal slope; producing conditions suitable for unchannelled valley bottom wetland formation.
- Full Text:
- Date Issued: 2018
Discovery and validation of a CD4 binding aptamer through Crossover SELEX towards the preliminary development of a point-of-care aptasensor for rapid CD4+ T-cell counting
- Authors: Fellows, Tamika
- Date: 2018
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63527 , vital:28431
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018
- Authors: Fellows, Tamika
- Date: 2018
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63527 , vital:28431
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018
Donor-acceptor effects on the optical limiting properties of BODIPY dyes
- Authors: Hlatshwayo, Zweli Thabiso
- Date: 2018
- Subjects: Dyes and dyeing -- Chemistry , Photosensitizing compounds -- Therapeutic use , Cancer -- Photochemotherapy , Upconversion nanoparticles (UCNPs)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63368 , vital:28397
- Description: The main objectives of the research described in this thesis were firstly to synthesize and characterize a series of structurally related BODIPY dyes that are potentially suitable for use in applications, secondly to conjugate a carboxylic acid substituted BODIPY dye to amine-functionalized upconversion nanoparticles (UCNPs) through an amide bond to enable singlet oxygen production upon irradiation at 978 nm in the biological window for tissue penetration for biomedical applications, and thirdly to compare the nonlinear optical (NLO) properties of various BODIPY dyes to determine whether push-pull effects enhance their utility for optical limiting (OL) applications. Halogenated BODIPY cores with high singlet oxygen quantum yields were prepared, which absorb in the green portion of the visible region and making it difficult to treat deeper skin tumors in the context of photodynamic therapy (PDT) applications. UCNPs generally absorb in the near-infrared (NIR) region (978 nm), and this is advantageous because, this is where absorption by water, cells and tissues is minimized. NaYF4: Yb/Er/Gd UCNPs were synthesized, amine functionalized and successfully conjugated to a halogenated carboxylic acid functionalized BODIPY. This allowed for favorable Förster resonance energy transfer (FRET) since one of the emission wavelengths of the NaYF4: Yb/Er/Gd UCNPs overlaps with the main absorption band of the BODIPY at 540 nm. The conjugate was irradiated at 978 nm, but instability of the BODIPY dye was observed, which made singlet oxygen quantum yield determination impossible. An enhanced singlet oxygen quantum yield value was observed upon irradiation of the conjugate at 540 nm, suggesting that further studies of this system are warranted. The OL properties of BODIPY cores and dyes, which are π-extended at the 3,5-positions with styryl groups, were studied in a series of different organic solvents at 532 nm by using the z-scan technique on a nanosecond timescale. Many of the dyes were used to compare the effects of introducing electron donor and acceptor groups on the OL properties of the dyes. The dipole moments of these dyes were found to correlate with the OL response. The OL results indicate that BODIPY dyes with push-pull properties, which are π-extended at the 3,5-positions with styryl groups, can be considered as viable candidates for use in OL applications. The studies sought to establish the effect of ESA in the triplet manifold as compared to the singlet manifold in as far as the OL response is concerned. The most promising dyes were embedded in polystyrene thin films, and this was found to significantly enhance their OL properties.
- Full Text:
- Date Issued: 2018
- Authors: Hlatshwayo, Zweli Thabiso
- Date: 2018
- Subjects: Dyes and dyeing -- Chemistry , Photosensitizing compounds -- Therapeutic use , Cancer -- Photochemotherapy , Upconversion nanoparticles (UCNPs)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63368 , vital:28397
- Description: The main objectives of the research described in this thesis were firstly to synthesize and characterize a series of structurally related BODIPY dyes that are potentially suitable for use in applications, secondly to conjugate a carboxylic acid substituted BODIPY dye to amine-functionalized upconversion nanoparticles (UCNPs) through an amide bond to enable singlet oxygen production upon irradiation at 978 nm in the biological window for tissue penetration for biomedical applications, and thirdly to compare the nonlinear optical (NLO) properties of various BODIPY dyes to determine whether push-pull effects enhance their utility for optical limiting (OL) applications. Halogenated BODIPY cores with high singlet oxygen quantum yields were prepared, which absorb in the green portion of the visible region and making it difficult to treat deeper skin tumors in the context of photodynamic therapy (PDT) applications. UCNPs generally absorb in the near-infrared (NIR) region (978 nm), and this is advantageous because, this is where absorption by water, cells and tissues is minimized. NaYF4: Yb/Er/Gd UCNPs were synthesized, amine functionalized and successfully conjugated to a halogenated carboxylic acid functionalized BODIPY. This allowed for favorable Förster resonance energy transfer (FRET) since one of the emission wavelengths of the NaYF4: Yb/Er/Gd UCNPs overlaps with the main absorption band of the BODIPY at 540 nm. The conjugate was irradiated at 978 nm, but instability of the BODIPY dye was observed, which made singlet oxygen quantum yield determination impossible. An enhanced singlet oxygen quantum yield value was observed upon irradiation of the conjugate at 540 nm, suggesting that further studies of this system are warranted. The OL properties of BODIPY cores and dyes, which are π-extended at the 3,5-positions with styryl groups, were studied in a series of different organic solvents at 532 nm by using the z-scan technique on a nanosecond timescale. Many of the dyes were used to compare the effects of introducing electron donor and acceptor groups on the OL properties of the dyes. The dipole moments of these dyes were found to correlate with the OL response. The OL results indicate that BODIPY dyes with push-pull properties, which are π-extended at the 3,5-positions with styryl groups, can be considered as viable candidates for use in OL applications. The studies sought to establish the effect of ESA in the triplet manifold as compared to the singlet manifold in as far as the OL response is concerned. The most promising dyes were embedded in polystyrene thin films, and this was found to significantly enhance their OL properties.
- Full Text:
- Date Issued: 2018
Effects of CO2-induced ocean acidification on the early development, growth, survival and skeletogenesis of the estuarine-dependant sciaenid Argyrosomus japonicus
- Authors: Erasmus, Bernard
- Date: 2018
- Subjects: Argyrosomus , Argyrosomus -- Growth , Argyrosomus -- Mortality , Argyrosomus -- Ecology , Argyrosomus -- Physiology , Ocean acidification , Marine ecology -- South Africa , Carbon dioxide -- Physiological effect
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60585 , vital:27799
- Description: Although it is increasingly accepted that ocean acidification poses a considerable threat to marine organisms, little is known about the likely response of fishes to this phenomenon. While initial research concluded that adult fishes may be tolerant to changes predicted in the next 300 years, the response of early life stages to end-of-century CO2 levels (~ 1100 µatm according to the IPCC RCP 8.5) remains unclear. To date, literature on the early growth and survival of fishes has yielded conflicting results, suggesting that vulnerability may be species dependant. The paucity of ocean acidification research on fishes is particularly evident when one considers larval skeletogenesis, with no robust studies on its impacts on bone and cartilage development. This study addresses the early life embryogenesis, hatching success, growth, skeletogenesis and survival of an estuarine-dependant species. Dusky kob (Argyrosomus japonicus) were reared in a control (pCO2 = 327.50 ± 80.07 qatm at pH 8.15), intermediate (pCO2 477.40 ± 59.46 qatm at pH 8.03) and high pCO2 treatment (pCO2 910.20 ± 136.45 qatm at pH 7.78) from egg to 29 days post-hatch (dph). Sixty individuals from each treatment were sacrificed at the egg stage and at 2, 6, 13, 18, 21 and 26 dph, measured and stained using an acid-free double- staining solution to prevent the deterioration of calcified matrices in fragile larval skeletons. The proportion of bone and cartilage was quantified at each stage using a novel pixel-counting method. Growth and skeletal development were identical between treatments until the onset of metamorphosis (21 dph). However, from the metamorphosis stage, the growth and skeletal development rate was significantly faster in the intermediate treatment and significantly slower in the high treatment when compared to the control treatment. By 26 dph, A. japonicus reared in high pCO2 were, on average, 47.2% smaller than the control treatment, and the relative proportion of bone in the body was 45.3% lower in the high pCO2 treatment when compared with the control. In addition, none of the fish in the high pCO2 treatment survived after 26 dph. It appears that the combination of the increased energy requirements during metamorphosis and the increased energy cost associated with acid-base regulation may account for reduced growth, skeletogenesis and poor survival in high pCO2. Regardless of the driver, the results of this study suggest that the pCO2 levels predicted for the end of the century may have negative effects on the growth, skeletal development, and survival during metamorphosis.
- Full Text:
- Date Issued: 2018
- Authors: Erasmus, Bernard
- Date: 2018
- Subjects: Argyrosomus , Argyrosomus -- Growth , Argyrosomus -- Mortality , Argyrosomus -- Ecology , Argyrosomus -- Physiology , Ocean acidification , Marine ecology -- South Africa , Carbon dioxide -- Physiological effect
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/60585 , vital:27799
- Description: Although it is increasingly accepted that ocean acidification poses a considerable threat to marine organisms, little is known about the likely response of fishes to this phenomenon. While initial research concluded that adult fishes may be tolerant to changes predicted in the next 300 years, the response of early life stages to end-of-century CO2 levels (~ 1100 µatm according to the IPCC RCP 8.5) remains unclear. To date, literature on the early growth and survival of fishes has yielded conflicting results, suggesting that vulnerability may be species dependant. The paucity of ocean acidification research on fishes is particularly evident when one considers larval skeletogenesis, with no robust studies on its impacts on bone and cartilage development. This study addresses the early life embryogenesis, hatching success, growth, skeletogenesis and survival of an estuarine-dependant species. Dusky kob (Argyrosomus japonicus) were reared in a control (pCO2 = 327.50 ± 80.07 qatm at pH 8.15), intermediate (pCO2 477.40 ± 59.46 qatm at pH 8.03) and high pCO2 treatment (pCO2 910.20 ± 136.45 qatm at pH 7.78) from egg to 29 days post-hatch (dph). Sixty individuals from each treatment were sacrificed at the egg stage and at 2, 6, 13, 18, 21 and 26 dph, measured and stained using an acid-free double- staining solution to prevent the deterioration of calcified matrices in fragile larval skeletons. The proportion of bone and cartilage was quantified at each stage using a novel pixel-counting method. Growth and skeletal development were identical between treatments until the onset of metamorphosis (21 dph). However, from the metamorphosis stage, the growth and skeletal development rate was significantly faster in the intermediate treatment and significantly slower in the high treatment when compared to the control treatment. By 26 dph, A. japonicus reared in high pCO2 were, on average, 47.2% smaller than the control treatment, and the relative proportion of bone in the body was 45.3% lower in the high pCO2 treatment when compared with the control. In addition, none of the fish in the high pCO2 treatment survived after 26 dph. It appears that the combination of the increased energy requirements during metamorphosis and the increased energy cost associated with acid-base regulation may account for reduced growth, skeletogenesis and poor survival in high pCO2. Regardless of the driver, the results of this study suggest that the pCO2 levels predicted for the end of the century may have negative effects on the growth, skeletal development, and survival during metamorphosis.
- Full Text:
- Date Issued: 2018
Engaging with media as a knowledge resource for making sense of climate change: a case study of the farmers of Nyanga, Zimbabwe
- Authors: Mandikonza, Blessing
- Date: 2018
- Subjects: Climatic changes in mass media , Knowledge, Sociology of , Farms, Small -- Zimbabwe -- Nyanga , Crops and climate -- Zimbabwe -- Nyanga , Agriculture -- Economic aspects -- Zimbabwe , Agriculture -- Environmental aspects -- Zimbabwe -- Nyanga , Agriculture and politics -- Zimbabwe -- Nyanga , Agriculture -- Research -- Sociological aspects , Agricultural journalism -- Zimbabwe , Land reform -- Zimbabwe -- Nyanga
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/63764 , vital:28486
- Description: This study explores how small-scale farmers in Nyanga, Zimbabwe engage with the media as a knowledge resource for achieving agricultural productivity, particularly in context of climate change. The study is contextualised by means of a literature review that maps out the history of agricultural productivity in Zimbabwe. It is argued that this history has been shaped by changes in both socio-economic context and climatic conditions. Both kinds of change impact on the degree to which small-scale farmers have access to knowledge that is of relevance to agricultural productivity. The study then examines the Zimbabwean media landscape, focusing on how history has shaped the way in which different media define their social purpose. This examination draws on Hallin and Mancini‟s „models‟ of media systems as well as Christian et al‟s traditions of media practice. It is concluded that, due to the high level of conflict that has characterised Zimbabwean history, aspects of both the polarised pluralist and democratic corporatist models are present in its media landscape. The collaborative, monitorial and radical approaches to media also exist in contestation with each other. Indeed, the media is characterised by profound contestation around the conceptualisation of social purpose. Furthermore, international media is of particular significance as a resource of knowledge within the local media landscape. The empirical component of the study explores the implications for the extent to which media are likely to serve as valuable knowledge resources for small-scale farmers. This exploration is pursued by means of a case study of the experiences of three farmers in Nyanga who were granted farms as part of the government‟s land-reform programme. In context of episodic biographical interviews, the participants share their experience of becoming farmers and of managing their farms. Attention is paid to the challenges they face with regards to producing successful crops, both in context of socio-economic and climatic conditions. The study looks at the way in which participants draw on the media as a knowledge resource to help them overcome these challenges. The participants understand international media to be a more credible knowledge resource, but also refer to the need for local media which can provides them with knowledge of local relevance. In this context they identify an absence of collaborative, developmental media that engages with the unique challenges that they face in producing crops. It is concluded that the value of media for the farmers of Nyanga as a knowledge resource for making sense of climate change would only be achieved through the establishment of locally produced, participatory media that foregrounds the use of indigenous language.
- Full Text:
- Date Issued: 2018
- Authors: Mandikonza, Blessing
- Date: 2018
- Subjects: Climatic changes in mass media , Knowledge, Sociology of , Farms, Small -- Zimbabwe -- Nyanga , Crops and climate -- Zimbabwe -- Nyanga , Agriculture -- Economic aspects -- Zimbabwe , Agriculture -- Environmental aspects -- Zimbabwe -- Nyanga , Agriculture and politics -- Zimbabwe -- Nyanga , Agriculture -- Research -- Sociological aspects , Agricultural journalism -- Zimbabwe , Land reform -- Zimbabwe -- Nyanga
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/63764 , vital:28486
- Description: This study explores how small-scale farmers in Nyanga, Zimbabwe engage with the media as a knowledge resource for achieving agricultural productivity, particularly in context of climate change. The study is contextualised by means of a literature review that maps out the history of agricultural productivity in Zimbabwe. It is argued that this history has been shaped by changes in both socio-economic context and climatic conditions. Both kinds of change impact on the degree to which small-scale farmers have access to knowledge that is of relevance to agricultural productivity. The study then examines the Zimbabwean media landscape, focusing on how history has shaped the way in which different media define their social purpose. This examination draws on Hallin and Mancini‟s „models‟ of media systems as well as Christian et al‟s traditions of media practice. It is concluded that, due to the high level of conflict that has characterised Zimbabwean history, aspects of both the polarised pluralist and democratic corporatist models are present in its media landscape. The collaborative, monitorial and radical approaches to media also exist in contestation with each other. Indeed, the media is characterised by profound contestation around the conceptualisation of social purpose. Furthermore, international media is of particular significance as a resource of knowledge within the local media landscape. The empirical component of the study explores the implications for the extent to which media are likely to serve as valuable knowledge resources for small-scale farmers. This exploration is pursued by means of a case study of the experiences of three farmers in Nyanga who were granted farms as part of the government‟s land-reform programme. In context of episodic biographical interviews, the participants share their experience of becoming farmers and of managing their farms. Attention is paid to the challenges they face with regards to producing successful crops, both in context of socio-economic and climatic conditions. The study looks at the way in which participants draw on the media as a knowledge resource to help them overcome these challenges. The participants understand international media to be a more credible knowledge resource, but also refer to the need for local media which can provides them with knowledge of local relevance. In this context they identify an absence of collaborative, developmental media that engages with the unique challenges that they face in producing crops. It is concluded that the value of media for the farmers of Nyanga as a knowledge resource for making sense of climate change would only be achieved through the establishment of locally produced, participatory media that foregrounds the use of indigenous language.
- Full Text:
- Date Issued: 2018
Essence of home: relevance of home and the assertion of place amongst Centane migrants, South Africa
- Authors: Njwambe, Avela Thandisiwe
- Date: 2018
- Subjects: Rural-urban migration -- South Africa , Migrant labor -- South Africa , Immigrants -- South Africa -- Social conditions , Immigrants -- South Africa -- Eastern Cape , Immigrants -- South Africa -- Homelands , Homelands (South Africa) , Home -- Psychological aspects
- Language: English
- Type: text , Thesis , Masters , MSocSc
- Identifier: http://hdl.handle.net/10962/51866 , vital:26136
- Description: South Africa is currently experiencing ever-increasing rural-urban migration with many citizens from the former homeland areas migrating to cities to seek employment. Despite long-term residence in urban areas, many township dwellers do not consider these places to be home. Research into circular migration patterns reveal the lifelong relationships that migrants (amagoduka) have with their family home (ekhayeni). This study aimed to explore this relationship, looking in particular at the meanings imbued in the locality of home. In addition, the role of natural landscapes and social components in constructing meanings and attachments to ekhayeni for Xhosa-speaking migrants in Cape Town townships, who have family linkages to rural villages in the Transkei, was also explored. The study found that the landscape of home remains central to migrants’ cultural identity, belonging and well-being. Childhood experiences in nature, and cultural and recreational activities that continue to take rural inhabitants into these landscapes, remain key to this relationship. The rural area, as a geographical entity embodied with social and cultural/spiritual components continued to supply and satisfy many human needs for migrants, which were seen as crucial for psychological, mental and spiritual well-being.
- Full Text:
- Date Issued: 2018
Essence of home: relevance of home and the assertion of place amongst Centane migrants, South Africa
- Authors: Njwambe, Avela Thandisiwe
- Date: 2018
- Subjects: Rural-urban migration -- South Africa , Migrant labor -- South Africa , Immigrants -- South Africa -- Social conditions , Immigrants -- South Africa -- Eastern Cape , Immigrants -- South Africa -- Homelands , Homelands (South Africa) , Home -- Psychological aspects
- Language: English
- Type: text , Thesis , Masters , MSocSc
- Identifier: http://hdl.handle.net/10962/51866 , vital:26136
- Description: South Africa is currently experiencing ever-increasing rural-urban migration with many citizens from the former homeland areas migrating to cities to seek employment. Despite long-term residence in urban areas, many township dwellers do not consider these places to be home. Research into circular migration patterns reveal the lifelong relationships that migrants (amagoduka) have with their family home (ekhayeni). This study aimed to explore this relationship, looking in particular at the meanings imbued in the locality of home. In addition, the role of natural landscapes and social components in constructing meanings and attachments to ekhayeni for Xhosa-speaking migrants in Cape Town townships, who have family linkages to rural villages in the Transkei, was also explored. The study found that the landscape of home remains central to migrants’ cultural identity, belonging and well-being. Childhood experiences in nature, and cultural and recreational activities that continue to take rural inhabitants into these landscapes, remain key to this relationship. The rural area, as a geographical entity embodied with social and cultural/spiritual components continued to supply and satisfy many human needs for migrants, which were seen as crucial for psychological, mental and spiritual well-being.
- Full Text:
- Date Issued: 2018
Exploration potential for copperbelt - style mineralisation in NW Province, Zambia; soil geochemistry as a targeting tool
- Authors: Mwamba, John
- Date: 2018
- Subjects: Mineralogy -- Zambia -- Copperbelt Province , River sediments -- Zambia -- Copperbelt Province , Soils -- Sampling -- Zambia -- Copperbelt Province , Prospecting -- Geophysical methods , Landsat satellites , Lufilian fold belt
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62538 , vital:28204
- Description: The NW Province of Zambia is fast becoming a major significant mining district challenging to usurp the economic importance of the traditional Copperbelt Province that has been mined for nearly a century. With latest developments at Kansanshi, Lumwana and Kalumbila mines exploration efforts in the search for Copperbelt style mineralisation have doubled up in the province in recent months. Traditional methods of stream sediment and soil sampling, geophysics, aerial photo and Landsat imagery interpretations have been employed in exploration targeting campaigns. This thesis asks the question: Can we use the Copperbelt geochemical footprint as a proxy to finding new copper deposits in NW Province? The challenge faced in such studies is that few geochemical datasets for old mines exist and the little that does is proprietary information. In some mines this dataset is entirely nonexistent - at least not in the public domain. Attempting to run orientation geochemical trials on such mines is not feasible at present due to maturity of mining and the levels of contamination of the natural environment that have occurred over several decades of mining. However, in tackling this question few Copperbelt geochemical datasets from Baluba, Nkana, Mimbula, Nchanga, Bwana Mkubwa, Mufulira West and Lufubu North were used. The findings presented in this report are that for Copperbelt style mineralisation Cu/Co, Cu/Ni, Cu/Ag ratios in soil geochemistry data should be in the ranges of 0.25 to 0.48 provided geochemical studies occurred in residual soils. These ratios hold true for sediment hosted copper-cobalt mineralisation hosted at various stratigraphic levels within the Roan Group or in upper levels elsewhere on the Central African Copperbelt. Geochemical dataset for the study areas presented in this report show that the soil geochemistry footprint in the province is not dissimilar to the soil geochemistry footprint of the traditional Copperbelt Province. This means there is great potential for finding Copperbelt style mineralisation in the province and other styles of mineralisation in which copper is associated with cobalt, lead, zinc, nickel, vanadium and molybdenum. The areas of study also possess requisite geological factors that are conducive to hosting Copperbelt style deposits. These factors include: favourable structural traps with similar trends to existing mines in the province, geophysical characteristics comparable to other deposits in the province, right geological package known to host multi-type deposits in the Katangan stratigraphic sequence, and similar geochemical footprints observed on other deposits within the Lufilian fold belt. For this reason, geochemical dataset must not be looked at in isolation but should be treated in considerations with other factors and geological environment.
- Full Text:
- Date Issued: 2018
- Authors: Mwamba, John
- Date: 2018
- Subjects: Mineralogy -- Zambia -- Copperbelt Province , River sediments -- Zambia -- Copperbelt Province , Soils -- Sampling -- Zambia -- Copperbelt Province , Prospecting -- Geophysical methods , Landsat satellites , Lufilian fold belt
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62538 , vital:28204
- Description: The NW Province of Zambia is fast becoming a major significant mining district challenging to usurp the economic importance of the traditional Copperbelt Province that has been mined for nearly a century. With latest developments at Kansanshi, Lumwana and Kalumbila mines exploration efforts in the search for Copperbelt style mineralisation have doubled up in the province in recent months. Traditional methods of stream sediment and soil sampling, geophysics, aerial photo and Landsat imagery interpretations have been employed in exploration targeting campaigns. This thesis asks the question: Can we use the Copperbelt geochemical footprint as a proxy to finding new copper deposits in NW Province? The challenge faced in such studies is that few geochemical datasets for old mines exist and the little that does is proprietary information. In some mines this dataset is entirely nonexistent - at least not in the public domain. Attempting to run orientation geochemical trials on such mines is not feasible at present due to maturity of mining and the levels of contamination of the natural environment that have occurred over several decades of mining. However, in tackling this question few Copperbelt geochemical datasets from Baluba, Nkana, Mimbula, Nchanga, Bwana Mkubwa, Mufulira West and Lufubu North were used. The findings presented in this report are that for Copperbelt style mineralisation Cu/Co, Cu/Ni, Cu/Ag ratios in soil geochemistry data should be in the ranges of 0.25 to 0.48 provided geochemical studies occurred in residual soils. These ratios hold true for sediment hosted copper-cobalt mineralisation hosted at various stratigraphic levels within the Roan Group or in upper levels elsewhere on the Central African Copperbelt. Geochemical dataset for the study areas presented in this report show that the soil geochemistry footprint in the province is not dissimilar to the soil geochemistry footprint of the traditional Copperbelt Province. This means there is great potential for finding Copperbelt style mineralisation in the province and other styles of mineralisation in which copper is associated with cobalt, lead, zinc, nickel, vanadium and molybdenum. The areas of study also possess requisite geological factors that are conducive to hosting Copperbelt style deposits. These factors include: favourable structural traps with similar trends to existing mines in the province, geophysical characteristics comparable to other deposits in the province, right geological package known to host multi-type deposits in the Katangan stratigraphic sequence, and similar geochemical footprints observed on other deposits within the Lufilian fold belt. For this reason, geochemical dataset must not be looked at in isolation but should be treated in considerations with other factors and geological environment.
- Full Text:
- Date Issued: 2018
Exploring the adaptability and applicability of military mental skills training for South African paramedics
- Authors: Minnie, Chantel
- Date: 2018
- Subjects: Allied health personnel -- South Africa , Allied health personnel -- Mental health -- South Africa , Post-traumatic stress disorder -- South Africa , Emergency medical services -- Psychological aspects
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/61580 , vital:28039
- Description: Paramedics in South Africa are among the best in the world (MacFarlane, van Loggerenberg, & Kloeck, 2005). However, the domain of pre-hospital emergency care is fraught with challenges and paramedics face numerous personal and professional difficulties. South Africa, with its diverse patient population and challenges, cannot afford to undermine the importance of supportive interventions for emergency medical technicians. Whilst there is a growing body of literature examining the effectiveness of mental skills training in the sporting domain (Gould, Dieffenbach, & Moffett, 2002; Landers & Boutcher, 1998), there is a lack of research on mental skills training as it pertains to paramedics. It is argued here, that the use of mental skills training derived from sporting science and adapted for the military, provides the most comparable context in relation to the paramedic industry. This study thus aims to explore the adaptability and applicability of military mental skills training techniques in the context of South African paramedics. This study made use of an exploratory, qualitative case study design, focusing on participatory research strategies. The analysis revealed that various aspects of existing military mental skills models can be adapted to be of relevance in the emergency medical services field as it related to three paramedic participants. A prominent emerging theme was that of PTSD among paramedics, and it was an area that the participants felt should receive much more attention, research and intervention.
- Full Text:
- Date Issued: 2018
- Authors: Minnie, Chantel
- Date: 2018
- Subjects: Allied health personnel -- South Africa , Allied health personnel -- Mental health -- South Africa , Post-traumatic stress disorder -- South Africa , Emergency medical services -- Psychological aspects
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/61580 , vital:28039
- Description: Paramedics in South Africa are among the best in the world (MacFarlane, van Loggerenberg, & Kloeck, 2005). However, the domain of pre-hospital emergency care is fraught with challenges and paramedics face numerous personal and professional difficulties. South Africa, with its diverse patient population and challenges, cannot afford to undermine the importance of supportive interventions for emergency medical technicians. Whilst there is a growing body of literature examining the effectiveness of mental skills training in the sporting domain (Gould, Dieffenbach, & Moffett, 2002; Landers & Boutcher, 1998), there is a lack of research on mental skills training as it pertains to paramedics. It is argued here, that the use of mental skills training derived from sporting science and adapted for the military, provides the most comparable context in relation to the paramedic industry. This study thus aims to explore the adaptability and applicability of military mental skills training techniques in the context of South African paramedics. This study made use of an exploratory, qualitative case study design, focusing on participatory research strategies. The analysis revealed that various aspects of existing military mental skills models can be adapted to be of relevance in the emergency medical services field as it related to three paramedic participants. A prominent emerging theme was that of PTSD among paramedics, and it was an area that the participants felt should receive much more attention, research and intervention.
- Full Text:
- Date Issued: 2018
Factors contributing to taxpayer morale: a multi-country perspective
- Authors: Kosiorek, Jakub
- Date: 2018
- Subjects: Taxpayer compliance -- South Africa , Tax evasion -- South Africa , Taxpayer compliance -- Social aspects -- South Africa , Taxpayer compliance -- Economic aspects -- South Africa , Tax morale -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/60255 , vital:27759
- Description: Tax morale is the intrinsic motivation to pay taxes that arises either from a belief that one should contribute towards society by paying taxes or from a moral obligation to pay taxes. The goals of this thesis were to identify the various factors that influence tax morale in a country and use these factors in order to attempt to determine whether tax morale in South Africa has improved or deteriorated over the years. A further goal of this thesis was to identify strategies that could be implemented by a country in order to improve the tax morale of its citizens. The period covered by this thesis is between the years 2000 and 2015. The factors that have an effect on tax morale were identified by a review of the literature. It was found that a number of factors appear to have an impact on tax morale, but certain of these factors are incapable of being directly influenced by tax administrations. With regard to South Africa, it was found that a number of factors affecting tax morale appear to have improved over the years, while others had deteriorated. However, overall it appeared that tax morale in South Africa had deteriorated. With regard to strategies that could be used to improve tax morale, a number were identified by reviewing the literature and include strategies implemented in certain countries, as well as those discussed by scholars. Ii was found that South Africa had implemented a number of the strategies aimed at improving tax morale in its own tax system, but the manner in which some of them were implemented could have been improved. Furthermore, a number of strategies were identified that South Africa has not yet implemented and thus should look to attempting to implement these strategies to improve tax morale.
- Full Text:
- Date Issued: 2018
- Authors: Kosiorek, Jakub
- Date: 2018
- Subjects: Taxpayer compliance -- South Africa , Tax evasion -- South Africa , Taxpayer compliance -- Social aspects -- South Africa , Taxpayer compliance -- Economic aspects -- South Africa , Tax morale -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/60255 , vital:27759
- Description: Tax morale is the intrinsic motivation to pay taxes that arises either from a belief that one should contribute towards society by paying taxes or from a moral obligation to pay taxes. The goals of this thesis were to identify the various factors that influence tax morale in a country and use these factors in order to attempt to determine whether tax morale in South Africa has improved or deteriorated over the years. A further goal of this thesis was to identify strategies that could be implemented by a country in order to improve the tax morale of its citizens. The period covered by this thesis is between the years 2000 and 2015. The factors that have an effect on tax morale were identified by a review of the literature. It was found that a number of factors appear to have an impact on tax morale, but certain of these factors are incapable of being directly influenced by tax administrations. With regard to South Africa, it was found that a number of factors affecting tax morale appear to have improved over the years, while others had deteriorated. However, overall it appeared that tax morale in South Africa had deteriorated. With regard to strategies that could be used to improve tax morale, a number were identified by reviewing the literature and include strategies implemented in certain countries, as well as those discussed by scholars. Ii was found that South Africa had implemented a number of the strategies aimed at improving tax morale in its own tax system, but the manner in which some of them were implemented could have been improved. Furthermore, a number of strategies were identified that South Africa has not yet implemented and thus should look to attempting to implement these strategies to improve tax morale.
- Full Text:
- Date Issued: 2018
Factors influencing estuarine and coastal connectivity of an estuarine-dependent fishery species, Pomadasys commersonnii (Haemulidae)
- Authors: Dames, Michael Henri
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62307 , vital:28153
- Description: Expected release date-April 2019
- Full Text:
- Date Issued: 2018
- Authors: Dames, Michael Henri
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62307 , vital:28153
- Description: Expected release date-April 2019
- Full Text:
- Date Issued: 2018
Featuring simplicity: jargon and access in contemporary South African art
- Authors: Bereng, Lerato
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/60479 , vital:27784
- Description: The focus of this paper is an exploration of curating and its various forms as understood in a South African art context. In order to understand this context I examine definitions of South African publics as well as different curatorial models. I raise questions around art and accessibility as well as the functions of language as a gate keeper within the visual arts. Through a practical exploration of curatorial methods of engagement, I assess the curator's role as disseminator of information. My final project Conversations at Morija that was held in Morija, Lesotho faces the challenge of curating within a space that has a strong creative platform, but lacks a visual art audience. The exhibition was held during the 2013 Morija Art and Culture festival which is dominated by its music component. Despite Morija being the country's creative centre and sole museum, there is little support for its programme both monetary and in terms of attendance. Through a series of conversations several issues pertaining to Morija, Lesotho and the diaspora were addressed. I look at the absence of creative platforms and alternative curatorial methods that engage the public in a participatory manner. Briefly exploring questions of migrant labour and definitions of what constitutes a diaspora. I look at relatable ways to engage the local audience whilst maintaining a creative core in which to spark dialogue around pertinent matters relating to the country.
- Full Text:
- Date Issued: 2018
- Authors: Bereng, Lerato
- Date: 2018
- Language: English
- Type: text , Thesis , Masters , MFA
- Identifier: http://hdl.handle.net/10962/60479 , vital:27784
- Description: The focus of this paper is an exploration of curating and its various forms as understood in a South African art context. In order to understand this context I examine definitions of South African publics as well as different curatorial models. I raise questions around art and accessibility as well as the functions of language as a gate keeper within the visual arts. Through a practical exploration of curatorial methods of engagement, I assess the curator's role as disseminator of information. My final project Conversations at Morija that was held in Morija, Lesotho faces the challenge of curating within a space that has a strong creative platform, but lacks a visual art audience. The exhibition was held during the 2013 Morija Art and Culture festival which is dominated by its music component. Despite Morija being the country's creative centre and sole museum, there is little support for its programme both monetary and in terms of attendance. Through a series of conversations several issues pertaining to Morija, Lesotho and the diaspora were addressed. I look at the absence of creative platforms and alternative curatorial methods that engage the public in a participatory manner. Briefly exploring questions of migrant labour and definitions of what constitutes a diaspora. I look at relatable ways to engage the local audience whilst maintaining a creative core in which to spark dialogue around pertinent matters relating to the country.
- Full Text:
- Date Issued: 2018
Formulation, characterisation and optimisation of self-nanoemulsifying drug delivery systems (SNEDDS) loaded with artemether and lumefantrine
- Authors: Mudyahoto, Tsitsi
- Date: 2018
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63503 , vital:28422
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018
- Authors: Mudyahoto, Tsitsi
- Date: 2018
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63503 , vital:28422
- Description: Expected release date-April 2020
- Full Text:
- Date Issued: 2018