Nonlinear optical properties of metal free thio alkyl and tert-butyl phenoxy phthalocyanine
- Authors: Joseph, Otto
- Date: 2021-10
- Subjects: Nonlinear optics , Phthalocyanines , Time-dependent density functional theory , Magnetic circular dichroism , Reverse saturable absorption (RSA) , Real Time Dependent Density Functional Theory (RT-TDDFT)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190712 , vital:45021
- Description: This work reports on the nonlinear optical properties of tetra - and octa substituted phthalocyanines (Pcs) utilising pentane thiol and 4-tertbutyl phenol as substituents. Their nonlinear absorption coefficient (𝛽) and absorption cross sections were determined using the Z-scan technique with a 10 ns pulse laser at 532 nm. The molecular second order hyperpolarizability Im[γ] was observed and the following Im[γ] trend was obtained for 𝛼-H2Pc(SC5H11)4 isomers, 5.93 ×10−31 (Cs) 2.24×10−32(D2h) > 1.21×10−32(C4h) > 1.05×10−32 (C2v) esu, respectively, in chloroform. Symmetry was seen to have an effect on the observed reverse saturable absorption (RSA) response. Based on the five level model rate equation nonlinear fit of the RSA response curves and Real Time Time Dependant Density Functional Theory (RT-TDDFT) results, the singlet excited state population dynamics was found to play a significant role in producing the observed Im[γ] trend. , Thesis (MSc) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Joseph, Otto
- Date: 2021-10
- Subjects: Nonlinear optics , Phthalocyanines , Time-dependent density functional theory , Magnetic circular dichroism , Reverse saturable absorption (RSA) , Real Time Dependent Density Functional Theory (RT-TDDFT)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190712 , vital:45021
- Description: This work reports on the nonlinear optical properties of tetra - and octa substituted phthalocyanines (Pcs) utilising pentane thiol and 4-tertbutyl phenol as substituents. Their nonlinear absorption coefficient (𝛽) and absorption cross sections were determined using the Z-scan technique with a 10 ns pulse laser at 532 nm. The molecular second order hyperpolarizability Im[γ] was observed and the following Im[γ] trend was obtained for 𝛼-H2Pc(SC5H11)4 isomers, 5.93 ×10−31 (Cs) 2.24×10−32(D2h) > 1.21×10−32(C4h) > 1.05×10−32 (C2v) esu, respectively, in chloroform. Symmetry was seen to have an effect on the observed reverse saturable absorption (RSA) response. Based on the five level model rate equation nonlinear fit of the RSA response curves and Real Time Time Dependant Density Functional Theory (RT-TDDFT) results, the singlet excited state population dynamics was found to play a significant role in producing the observed Im[γ] trend. , Thesis (MSc) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Date Issued: 2021-10
Lateral and vertical mineral-chemical variation in high-grade ores of the Kalahari Manganese Field, and implications for ore genesis and geometallurgy
- Authors: Motilaodi, Donald
- Date: 2022-10-14
- Subjects: Manganese ores , Geometallurgy , Hydrothermal alteration , Petrology , Mineralogy , Geochemistry
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/362972 , vital:65379
- Description: The Kalahari Manganese Field (KMF) is a world-class resource of manganese ore hosted by the Paleoproterozoic Hotazel banded iron formation. KMF ores are categorised into two main types, i.e., low-grade, carbonate rich, braunitic ore (Mn≤40wt%) and carbonate-free, high-grade, Ca-braunite+hausmannite ore (Mn≥44wt%). High-grade ores, also known as Wessels type from the homonymous mine in the northernmost KMF, are thought to have formed from variable degrees of hydrothermal carbonate and silica leaching from a low-grade ore precursor, termed Mamatwan-type after the homonymous mine in the southernmost KMF. This project aims to conduct a mineralogical and mineral-chemical study of representative manganese ore samples from a suite of drillcores intersecting both the upper and the lower layers in the northern KMF, covering the areas of Wessels, N’chwaning and Gloria mines. Petrographically, the high-grade Mn ore displays great variability in three-dimensional space. Texturally, the ores exhibit a great variety of textures which may or may not show preservation of the laminated and ovoidal textures that typify the postulated low-grade protore. There is also significant variation in the mineralogical and geochemical characteristics of the high-grade Mn ores both vertically and laterally. Vertical variation includes, probably for the first time, variability between the upper and lower ore layers within individual drillcores of the Hotazel sequence. Mineralogically, the ores contain variable modal abundances of the ore-forming minerals braunite (I, II, “new”) and hausmannite, and much less so of bixbyite, marokite and manganite. Common accessories include andradite, barite and low-Mn carbonate minerals. Chemically, the dominant ore minerals braunite and hausmannite, contain Fe up to 22 and 15wt% respectively, which accounts for the bulk of the iron contained in the ores. Braunite compositions also exhibit a large range with respect to their ratio of Ca/Si. Mineral-specific trace element concentrations for the same minerals measured by LA-ICP-MS, reveal generally large variations from one element to the other. When normalized against the trace element composition of bulk low-grade precursor ore, strong enrichments are recorded for both hausmannite and braunite in selected alkali/alkali earth elements, transition metals and lanthanides, such as Sc, Co, Zn, Cu, Pb, La, and Ce. These are akin to enrichments recorded in average high-grade ore. Although there is also no obvious relationship between Fe content in both hausmannite and braunite and their trace element abundances, the drillcore that captures high-grade ore with the highest trace element concentrations appears to be located most proximal to a major fault. Results collectively suggest that high-grade Mn ores of the KMF have undergone a complex hydrothermal history with a clear and significant metasomatic addition of trace elements into ore-forming minerals. First order trends in the mineralogical and mineral-chemical distribution of the ores in space, suggest hausmannite-dominated ores near the Hotazel suboutcrop, and an apparent decline in ore quality with braunite II-andradite-barite-calcite ores as the major graben fault is approached in a southwesterly direction. The latter trend appears to be at odds with prevailing fault-controlled alteration models. Elucidating that hydrothermal history of the Wessels-type high grade Mn ores of the KMF, will be crucial to understanding the compositional controls of these ores in space, and the potential impact thereof in terms of geometallurgy. , Thesis (MSc) -- Faculty of Science, Geology, 2022
- Full Text:
- Date Issued: 2022-10-14
- Authors: Motilaodi, Donald
- Date: 2022-10-14
- Subjects: Manganese ores , Geometallurgy , Hydrothermal alteration , Petrology , Mineralogy , Geochemistry
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/362972 , vital:65379
- Description: The Kalahari Manganese Field (KMF) is a world-class resource of manganese ore hosted by the Paleoproterozoic Hotazel banded iron formation. KMF ores are categorised into two main types, i.e., low-grade, carbonate rich, braunitic ore (Mn≤40wt%) and carbonate-free, high-grade, Ca-braunite+hausmannite ore (Mn≥44wt%). High-grade ores, also known as Wessels type from the homonymous mine in the northernmost KMF, are thought to have formed from variable degrees of hydrothermal carbonate and silica leaching from a low-grade ore precursor, termed Mamatwan-type after the homonymous mine in the southernmost KMF. This project aims to conduct a mineralogical and mineral-chemical study of representative manganese ore samples from a suite of drillcores intersecting both the upper and the lower layers in the northern KMF, covering the areas of Wessels, N’chwaning and Gloria mines. Petrographically, the high-grade Mn ore displays great variability in three-dimensional space. Texturally, the ores exhibit a great variety of textures which may or may not show preservation of the laminated and ovoidal textures that typify the postulated low-grade protore. There is also significant variation in the mineralogical and geochemical characteristics of the high-grade Mn ores both vertically and laterally. Vertical variation includes, probably for the first time, variability between the upper and lower ore layers within individual drillcores of the Hotazel sequence. Mineralogically, the ores contain variable modal abundances of the ore-forming minerals braunite (I, II, “new”) and hausmannite, and much less so of bixbyite, marokite and manganite. Common accessories include andradite, barite and low-Mn carbonate minerals. Chemically, the dominant ore minerals braunite and hausmannite, contain Fe up to 22 and 15wt% respectively, which accounts for the bulk of the iron contained in the ores. Braunite compositions also exhibit a large range with respect to their ratio of Ca/Si. Mineral-specific trace element concentrations for the same minerals measured by LA-ICP-MS, reveal generally large variations from one element to the other. When normalized against the trace element composition of bulk low-grade precursor ore, strong enrichments are recorded for both hausmannite and braunite in selected alkali/alkali earth elements, transition metals and lanthanides, such as Sc, Co, Zn, Cu, Pb, La, and Ce. These are akin to enrichments recorded in average high-grade ore. Although there is also no obvious relationship between Fe content in both hausmannite and braunite and their trace element abundances, the drillcore that captures high-grade ore with the highest trace element concentrations appears to be located most proximal to a major fault. Results collectively suggest that high-grade Mn ores of the KMF have undergone a complex hydrothermal history with a clear and significant metasomatic addition of trace elements into ore-forming minerals. First order trends in the mineralogical and mineral-chemical distribution of the ores in space, suggest hausmannite-dominated ores near the Hotazel suboutcrop, and an apparent decline in ore quality with braunite II-andradite-barite-calcite ores as the major graben fault is approached in a southwesterly direction. The latter trend appears to be at odds with prevailing fault-controlled alteration models. Elucidating that hydrothermal history of the Wessels-type high grade Mn ores of the KMF, will be crucial to understanding the compositional controls of these ores in space, and the potential impact thereof in terms of geometallurgy. , Thesis (MSc) -- Faculty of Science, Geology, 2022
- Full Text:
- Date Issued: 2022-10-14
Biton’s Lost Siege Engine: Experimental archaeology in Classical Studies
- Authors: Rademan, David John
- Date: 2021-10-29
- Subjects: Pergamum (Extinct city) , Dimensional analysis , Engineering History To 168 B.C. , Fluid mechanics History To 168 B.C. , Byzantine literature History and criticism , Siege warfare History To 168 B.C. , Biton of Pergamon , Isidorus of Abydos , Poliorcetics
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192330 , vital:45216
- Description: This thesis entails an examination of several problems inherent in placing a technical treatise by the Hellenistic Greek engineer, Biton of Pergamon, at a siege of 156-154BCE, with a view to galvanising the existing case of previous scholarship through a combined approach of literary, textual, geographical, and technical analysis. Particular focus is given to the following problems: technical errors in current translations of the treatise of Biton; technical considerations in scholars’ reproductions of a particular engine in the treatise; an assessment of the practical implications of the treatise in situ at the physical site of the ancient city of Pergamon in the second century BCE, as evidenced by archaeological findings and surveys; assessment of those implications by way of historical records of similar conflicts from the Hellenistic period; and suggesting a procedure of dimensional analysis for testing a hypothesis regarding the feasibility of the ancient engineer’s recommended engines as a stand-in for the city’s original defenses, in a manner that harmonises the methodologies of historicism and experimental archaeology with sound and appropriate modern engineering practice from the field of Fluid Mechanics. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Rademan, David John
- Date: 2021-10-29
- Subjects: Pergamum (Extinct city) , Dimensional analysis , Engineering History To 168 B.C. , Fluid mechanics History To 168 B.C. , Byzantine literature History and criticism , Siege warfare History To 168 B.C. , Biton of Pergamon , Isidorus of Abydos , Poliorcetics
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192330 , vital:45216
- Description: This thesis entails an examination of several problems inherent in placing a technical treatise by the Hellenistic Greek engineer, Biton of Pergamon, at a siege of 156-154BCE, with a view to galvanising the existing case of previous scholarship through a combined approach of literary, textual, geographical, and technical analysis. Particular focus is given to the following problems: technical errors in current translations of the treatise of Biton; technical considerations in scholars’ reproductions of a particular engine in the treatise; an assessment of the practical implications of the treatise in situ at the physical site of the ancient city of Pergamon in the second century BCE, as evidenced by archaeological findings and surveys; assessment of those implications by way of historical records of similar conflicts from the Hellenistic period; and suggesting a procedure of dimensional analysis for testing a hypothesis regarding the feasibility of the ancient engineer’s recommended engines as a stand-in for the city’s original defenses, in a manner that harmonises the methodologies of historicism and experimental archaeology with sound and appropriate modern engineering practice from the field of Fluid Mechanics. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
- Full Text:
- Date Issued: 2021-10-29
Observations of cosmic re-ionisation with the Hydrogen Epoch of Reionization Array: simulations of closure phase spectra
- Authors: Charles, Ntsikelelo
- Date: 2021-04
- Subjects: Epoch of reionization , Space interferometry , Astronomy -- Observations , Closure phase spectra
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/174470 , vital:42480
- Description: The 21 cm transition from neutral Hydrogen promises to be the best observational probe of the Epoch of Reionisation. It has driven the construction of the new generation of low frequency radio interferometric arrays, including the Hydrogen Epoch of Reionization Array (HERA). The main difficulty in measuring the 21 cm signal is the presence of bright foregrounds that require very accurate interferometric calibration. Thyagarajan et al. (2018) proposed the use of closure phase quantities as a means to detect the 21 cm signal, which has the advantage of being independent (to first order) from calibration errors and therefore, bypasses the need for accurate calibration. Closure phases are, however, affected by so-called direction dependent effects, e.g. the fact that the dishes - or antennas - of an interferometric array are not identical to each other and , therefore, yield different antenna primary beam responses. In this thesis, we investigate the impact of direction dependent effects on closure quantities and simulate the impact that primary antenna beams affected by mutual coupling have on the foreground closure phase and its power spectrum i.e. the power spectrum of the bispectrum phase (Thyagarajan et al., 2020). Our simulations show that primary beams affected by mutual coupling lead to an overall leakage of foreground power in the so-called EoR window, i.e. power from smooth-spectrum foregrounds is confined to low k modes. We quantified this effect and found that the leakage is up to ~ 8 orders magnitude higher than the case of an ideal beam at kǁ > 0:5 h Mpc-1. We also found that the foreground leakage is worse when edge antennas are included, as they have a more different primary beam compared to antennas at the centre of the array. The leakage magnitude is worse when bright foregrounds appear in the antenna sidelobes, as expected. Our simulations provide a useful framework to interpret observations and assess which power spectrum region is expected to be most contaminated by foreground power leakage.
- Full Text:
- Date Issued: 2021-04
- Authors: Charles, Ntsikelelo
- Date: 2021-04
- Subjects: Epoch of reionization , Space interferometry , Astronomy -- Observations , Closure phase spectra
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/174470 , vital:42480
- Description: The 21 cm transition from neutral Hydrogen promises to be the best observational probe of the Epoch of Reionisation. It has driven the construction of the new generation of low frequency radio interferometric arrays, including the Hydrogen Epoch of Reionization Array (HERA). The main difficulty in measuring the 21 cm signal is the presence of bright foregrounds that require very accurate interferometric calibration. Thyagarajan et al. (2018) proposed the use of closure phase quantities as a means to detect the 21 cm signal, which has the advantage of being independent (to first order) from calibration errors and therefore, bypasses the need for accurate calibration. Closure phases are, however, affected by so-called direction dependent effects, e.g. the fact that the dishes - or antennas - of an interferometric array are not identical to each other and , therefore, yield different antenna primary beam responses. In this thesis, we investigate the impact of direction dependent effects on closure quantities and simulate the impact that primary antenna beams affected by mutual coupling have on the foreground closure phase and its power spectrum i.e. the power spectrum of the bispectrum phase (Thyagarajan et al., 2020). Our simulations show that primary beams affected by mutual coupling lead to an overall leakage of foreground power in the so-called EoR window, i.e. power from smooth-spectrum foregrounds is confined to low k modes. We quantified this effect and found that the leakage is up to ~ 8 orders magnitude higher than the case of an ideal beam at kǁ > 0:5 h Mpc-1. We also found that the foreground leakage is worse when edge antennas are included, as they have a more different primary beam compared to antennas at the centre of the array. The leakage magnitude is worse when bright foregrounds appear in the antenna sidelobes, as expected. Our simulations provide a useful framework to interpret observations and assess which power spectrum region is expected to be most contaminated by foreground power leakage.
- Full Text:
- Date Issued: 2021-04
An assessment of the wild cyclopia subternata (vleitee) resource
- Authors: Van der Walt, Wouter
- Date: 2021-04
- Subjects: Legumes -- South Africa , Fynbos -- South Africa , Fynbos ecology -- South Africa , Fynbos -- Harvesting -- South Africa , Biodiversity conservation -- South Africa , Traditional ecological knowledge -- South Africa , Wild Cyclopia Subternata (Vleitee) , Honeybush tea industry
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/176874 , vital:42767
- Description: Cyclopia spp. is used for the production of Honeybush tea, an herbal tea which is used in many cases as a substitute for rooibos tea. The wild harvesting of this fynbos plant still brings in up to 85% of the annual crop and as such needs to be carefully monitored in order to avoid over harvesting and the destruction of biodiversity within the Eastern and Western Cape mountain regions of Southern Africa. Due to the concerns of overharvesting and unsuitable use of the wild resource issues of supply security have been raised. There is a lack of formal knowledge relating to the plant, its harvesting, the industry and its economic potential. This study aimed to amend this scarcity by contributing to the knowledge of C. subternata as a wild harvested plant, the physical environment favoured by C. subternata, sustainable use through harvesting of the wild plant and harvesting methods specific to this honeybush species. The research concludes by presenting a guideline for best harvest practices of the wild C. subternata plant. , Thesis (MSc) -- Faculty of Science, Department of Geography, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Van der Walt, Wouter
- Date: 2021-04
- Subjects: Legumes -- South Africa , Fynbos -- South Africa , Fynbos ecology -- South Africa , Fynbos -- Harvesting -- South Africa , Biodiversity conservation -- South Africa , Traditional ecological knowledge -- South Africa , Wild Cyclopia Subternata (Vleitee) , Honeybush tea industry
- Language: English
- Type: thesis , text , Masters , MSc
- Identifier: http://hdl.handle.net/10962/176874 , vital:42767
- Description: Cyclopia spp. is used for the production of Honeybush tea, an herbal tea which is used in many cases as a substitute for rooibos tea. The wild harvesting of this fynbos plant still brings in up to 85% of the annual crop and as such needs to be carefully monitored in order to avoid over harvesting and the destruction of biodiversity within the Eastern and Western Cape mountain regions of Southern Africa. Due to the concerns of overharvesting and unsuitable use of the wild resource issues of supply security have been raised. There is a lack of formal knowledge relating to the plant, its harvesting, the industry and its economic potential. This study aimed to amend this scarcity by contributing to the knowledge of C. subternata as a wild harvested plant, the physical environment favoured by C. subternata, sustainable use through harvesting of the wild plant and harvesting methods specific to this honeybush species. The research concludes by presenting a guideline for best harvest practices of the wild C. subternata plant. , Thesis (MSc) -- Faculty of Science, Department of Geography, 2021
- Full Text:
- Date Issued: 2021-04
An ethnographic investigation of the implementation of the bilingual-bicultural approach for educating deaf learners focusing on South African sign language teaching at FET level
- Authors: Tunzelana, Nomava Mercy
- Date: 2021-10-29
- Subjects: South African Sign Language Study and teaching (Higher) , Sign language acquisition South Africa , Education, Bilingual South Africa , Biculturalism South Africa , Ethnology South Africa , Culturally relevant pedagogy South Africa , Deaf students South Africa , South Africa. Department of Basic Education , Curriculum-based assessment South Africa , South African Curriculum Assessment and Policy Statement (CAPS)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192353 , vital:45218
- Description: This half-thesis reports on an ethnographic investigation of the implementation of the Bilingual-Bicultural Approach for educating Deaf learners, focusing on South African Sign Language (SASL) teaching at the Further Education and Training (FET) level in a South African School for the Deaf in the Eastern Cape. The investigation occurs within the context of the introduction, in 2015, of the SASL Curriculum and Assessment Policy Statement (CAPS) by the Department of Basic Education (DBE). The SASL CAPS introduces an approach to teaching the Deaf known as the Bilingual-Bicultural Approach. This is an approach in which natural sign language (such as SASL) is taught first and used to learn a spoken language such as English for reading and writing. Previous research on a contrastive analysis of South African English and SASL reveals that SASL is a Topic-Comment language. It is sometimes Object-Subject-Verb (OSV) or Subject-Object-Verb (SOV) while the word order of South African English is Subject-Verb-Object (SVO). Semi-structured interviews of hearing and Deaf participants reveal serious tensions between the staff and the hearing staff because Deaf culture is not adhered to by some of the hearing staff. These tensions have a negative impact on the culture of learning and teaching at the school. Observations of four lessons at an FET class taught by an SASL FET teacher show that in her teaching, SASL syntax is used in keeping with the principles of the Bilingual-Bicultural Approach. However, her signing is accompanied by unvoiced spoken language due to the influence of a previously used approach called Total Communication (TC). One of the learners, Lulu, who contributes considerably more often than other learners in the lesson, also shows the same influence of TC. Other learners are either withdrawn or copy signs from Lulu. The study concludes with the recommendation that SASL be used for initiating newcomers to school as opposed to Signed English because research in bilingualism suggests that second language learners need one natural language established first before attempting to learn a second language. Teachers are recommended to immerse themselves into Deaf culture to acquire fluency. Comments from some participants suggest that teachers require vigorous training in the Bilingual-Bicultural Approach on a continuous basis. , Thesis (MA) -- Faculty of Humanities, Linguistics and Applied Languages Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Tunzelana, Nomava Mercy
- Date: 2021-10-29
- Subjects: South African Sign Language Study and teaching (Higher) , Sign language acquisition South Africa , Education, Bilingual South Africa , Biculturalism South Africa , Ethnology South Africa , Culturally relevant pedagogy South Africa , Deaf students South Africa , South Africa. Department of Basic Education , Curriculum-based assessment South Africa , South African Curriculum Assessment and Policy Statement (CAPS)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192353 , vital:45218
- Description: This half-thesis reports on an ethnographic investigation of the implementation of the Bilingual-Bicultural Approach for educating Deaf learners, focusing on South African Sign Language (SASL) teaching at the Further Education and Training (FET) level in a South African School for the Deaf in the Eastern Cape. The investigation occurs within the context of the introduction, in 2015, of the SASL Curriculum and Assessment Policy Statement (CAPS) by the Department of Basic Education (DBE). The SASL CAPS introduces an approach to teaching the Deaf known as the Bilingual-Bicultural Approach. This is an approach in which natural sign language (such as SASL) is taught first and used to learn a spoken language such as English for reading and writing. Previous research on a contrastive analysis of South African English and SASL reveals that SASL is a Topic-Comment language. It is sometimes Object-Subject-Verb (OSV) or Subject-Object-Verb (SOV) while the word order of South African English is Subject-Verb-Object (SVO). Semi-structured interviews of hearing and Deaf participants reveal serious tensions between the staff and the hearing staff because Deaf culture is not adhered to by some of the hearing staff. These tensions have a negative impact on the culture of learning and teaching at the school. Observations of four lessons at an FET class taught by an SASL FET teacher show that in her teaching, SASL syntax is used in keeping with the principles of the Bilingual-Bicultural Approach. However, her signing is accompanied by unvoiced spoken language due to the influence of a previously used approach called Total Communication (TC). One of the learners, Lulu, who contributes considerably more often than other learners in the lesson, also shows the same influence of TC. Other learners are either withdrawn or copy signs from Lulu. The study concludes with the recommendation that SASL be used for initiating newcomers to school as opposed to Signed English because research in bilingualism suggests that second language learners need one natural language established first before attempting to learn a second language. Teachers are recommended to immerse themselves into Deaf culture to acquire fluency. Comments from some participants suggest that teachers require vigorous training in the Bilingual-Bicultural Approach on a continuous basis. , Thesis (MA) -- Faculty of Humanities, Linguistics and Applied Languages Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
The factors to be considered by the competition authorities when a fine may cause the firm to exit
- Authors: Quilliam, Layne Edwin
- Date: 2021-10
- Subjects: South Africa. Competition Act, 1998 , Competition Tribunal (South Africa) , Business enterprises Law and legislation South Africa , Debt-to-equity ratio South Africa , Bankruptcy Prevention , Causation , Competition
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188408 , vital:44751
- Description: The Competition Act empowers the Competition Tribunal to levy fines against a firm for certain contraventions of the Act. Such fines are statutorily capped to prevent the fine from causing the firm’s exit. This maximum is based on the overarching principle of fairness which precludes a fine, on its own, from destroying a firm’s business. However, the Competition Appeal Court acknowledged in 2013 that fines below this cap may still cause a firm to exit. The purpose of this paper is to propose the factors that should be considered when determining a firm’s ability to pay such a below-cap fine. These factors are the calculation of the fine, probable exit, causation of exit and the competitive effect of the firm’s exit. The fining provisions of the Act are initially explored to provide context for the discussion and are then compared to equivalent provisions in Europe. Liquidation and business rescue proceedings are then described as the most common forms of a firm’s exit from the market. Methods for determining the causal relationship between the fine and the firm’s exit are explored through delictual law’s factual and legal causation. The competitive effects of the firm’s exit are premised on the purpose of the Competition Act and are evaluated through the Competition Act’s merger provisions, specifically, the failing firm factor. These proposed factors are then tested through hypothetical facts to analyse their possible interactions and efficacy. , Thesis (LLM) -- Faculty of Law, Law, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Quilliam, Layne Edwin
- Date: 2021-10
- Subjects: South Africa. Competition Act, 1998 , Competition Tribunal (South Africa) , Business enterprises Law and legislation South Africa , Debt-to-equity ratio South Africa , Bankruptcy Prevention , Causation , Competition
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188408 , vital:44751
- Description: The Competition Act empowers the Competition Tribunal to levy fines against a firm for certain contraventions of the Act. Such fines are statutorily capped to prevent the fine from causing the firm’s exit. This maximum is based on the overarching principle of fairness which precludes a fine, on its own, from destroying a firm’s business. However, the Competition Appeal Court acknowledged in 2013 that fines below this cap may still cause a firm to exit. The purpose of this paper is to propose the factors that should be considered when determining a firm’s ability to pay such a below-cap fine. These factors are the calculation of the fine, probable exit, causation of exit and the competitive effect of the firm’s exit. The fining provisions of the Act are initially explored to provide context for the discussion and are then compared to equivalent provisions in Europe. Liquidation and business rescue proceedings are then described as the most common forms of a firm’s exit from the market. Methods for determining the causal relationship between the fine and the firm’s exit are explored through delictual law’s factual and legal causation. The competitive effects of the firm’s exit are premised on the purpose of the Competition Act and are evaluated through the Competition Act’s merger provisions, specifically, the failing firm factor. These proposed factors are then tested through hypothetical facts to analyse their possible interactions and efficacy. , Thesis (LLM) -- Faculty of Law, Law, 2021
- Full Text:
- Date Issued: 2021-10
Media consumption and identity formation: the consumption of Latin American telenovelas in two neighbourhoods of Maputo in Mozambique
- Authors: Ofumane, Alvo Naftal
- Date: 2021-10-29
- Subjects: Television soap operas Mozambique Maputo , Identity (Psychology) and mass media Mozambique Maputo , Television soap operas History and criticism , Visual reception theory Mozambique Maputo , Mozambique Politics and government , Mozambique Social conditions , Mozambique Social life and customs
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192287 , vital:45212
- Description: This study explores how the residents of two neighbourhoods in Maputo, KaMaxakeni and KaMpfumo interact with and make meanings of (Latin American) telenovelas, as part of their identity formation process. It is guided by questions on how the residents of these two neighbourhoods interact with telenovelas in their daily lives; how this shapes their own values and understanding of themselves and the world in which they live; what aspects of telenovelas they value, and what meanings they make from them; and, finally, what determines their choices of media consumption. The study adopted reception theory, rooted in qualitative methodology. This approach explores the ‘insider’s’ perspective of the research subjects, taking the actors’ perspective as the empirical point of departure. Using a purposive theoretical sampling procedure, targeting those families who are avid viewers of telenovelas, the data were generated through participant observation, focus groups discussions, and individual interviews. To understand and interpret the interface between the telenovela (medium) and its viewers (audience) in Maputo, the study used qualitative thematic content analysis of the telenovelas viewing process by the residents of KaMpfumo and KaMaxakeni. The data show that the residents of KaMpfumo and KaMaxakeni in Maputo interact and make sense of the telenovelas in various ways. Telenovelas are used as an educational tool; they are used to reinforce daily life world practices; they s shape people’s personal character; they become another family presence; they are used to build or strengthen physical and virtual viewing networks, and, “Pure” telenovela viewing is a relatively rare occurrence. , Thesis (MA) -- Faculty of Humanities, Journalism and Media Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Ofumane, Alvo Naftal
- Date: 2021-10-29
- Subjects: Television soap operas Mozambique Maputo , Identity (Psychology) and mass media Mozambique Maputo , Television soap operas History and criticism , Visual reception theory Mozambique Maputo , Mozambique Politics and government , Mozambique Social conditions , Mozambique Social life and customs
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192287 , vital:45212
- Description: This study explores how the residents of two neighbourhoods in Maputo, KaMaxakeni and KaMpfumo interact with and make meanings of (Latin American) telenovelas, as part of their identity formation process. It is guided by questions on how the residents of these two neighbourhoods interact with telenovelas in their daily lives; how this shapes their own values and understanding of themselves and the world in which they live; what aspects of telenovelas they value, and what meanings they make from them; and, finally, what determines their choices of media consumption. The study adopted reception theory, rooted in qualitative methodology. This approach explores the ‘insider’s’ perspective of the research subjects, taking the actors’ perspective as the empirical point of departure. Using a purposive theoretical sampling procedure, targeting those families who are avid viewers of telenovelas, the data were generated through participant observation, focus groups discussions, and individual interviews. To understand and interpret the interface between the telenovela (medium) and its viewers (audience) in Maputo, the study used qualitative thematic content analysis of the telenovelas viewing process by the residents of KaMpfumo and KaMaxakeni. The data show that the residents of KaMpfumo and KaMaxakeni in Maputo interact and make sense of the telenovelas in various ways. Telenovelas are used as an educational tool; they are used to reinforce daily life world practices; they s shape people’s personal character; they become another family presence; they are used to build or strengthen physical and virtual viewing networks, and, “Pure” telenovela viewing is a relatively rare occurrence. , Thesis (MA) -- Faculty of Humanities, Journalism and Media Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
Towards Reconfiguring the Agricultural Expert System (AES) for Black Small to Medium Farmer Development for Commercialization: A progressively focused policy literature review and social learning dialogue in the Eastern Cape Raymond Mhlaba Local Municipality
- Authors: Maqwelane, Lwanda
- Date: 2021-10
- Subjects: Farms, Small South Africa Amathole District Municipality , Minority farmers , Public-private sector cooperation South Africa Amathole District Municipality , Social learning South Africa Amathole District Municipality , Agricultural expert system (AES) , Black small to medium farmers (BSMF)
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188876 , vital:44794
- Description: This study focuses on the agricultural expert system (AES), its inherited and potential reframing capabilities for the development, growth and transition of black small to medium farmers (BSMF) into the commercial sector. The study was conducted as a critical analytical policy review of implemented policies pre-and post 1994 that subsequently highlighted the thematic continuities and discontinuities of policy reform and the subsequent impact on BSMFs using the AES as a conceptual lens. The study aimed working with stakeholders in the AES in the Raymond Mhlaba Local Municipality as a case study to critically engage and question the AES and its contemporary framing and potential reframing and continued impact on the BSMFs development. This was conducted through a dialogical social learning process in partnership with diverse voices that cut across the contemporary agrarian landscape that included “universities, think tanks, vocational training providers, standards-setting agencies, trade associations that provide specialized training, education, information, research and technical support” (Porter, 2000, p.17). The data for the social learning dialogue process was generated through an iterative analysis of dialogical social learning workshops, focus groups and semi-structured interviews. The analysis focused on the framing (Chapters 2, 3, and 5) and reframing of the AES (Chapter 6). Through dynamic engagement within the knowledge hub (contextual social learning and literature), the study surfaces a potential alternative discourse that actively includes the BSMFs as a crucial component of the commercial sector AES as the analysis shows these are largely excluded. This alternative discourse occurred through dialogical interactions with all participants via a pro-actively constituted social learning process, enriched and deepened by literature as indicated above. Main recommendations of the study are: 1. The AES must be framed to address the holistic value chain of BSMFs to help address underlying policy dualism, 2. Public Private Partnerships are needed to support BSMFs development and these should adopt a social learning approach that is reflective of complex realities 3. There is need for better understanding of roles and contributions of stakeholders in the AES to avoid duplications. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Maqwelane, Lwanda
- Date: 2021-10
- Subjects: Farms, Small South Africa Amathole District Municipality , Minority farmers , Public-private sector cooperation South Africa Amathole District Municipality , Social learning South Africa Amathole District Municipality , Agricultural expert system (AES) , Black small to medium farmers (BSMF)
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188876 , vital:44794
- Description: This study focuses on the agricultural expert system (AES), its inherited and potential reframing capabilities for the development, growth and transition of black small to medium farmers (BSMF) into the commercial sector. The study was conducted as a critical analytical policy review of implemented policies pre-and post 1994 that subsequently highlighted the thematic continuities and discontinuities of policy reform and the subsequent impact on BSMFs using the AES as a conceptual lens. The study aimed working with stakeholders in the AES in the Raymond Mhlaba Local Municipality as a case study to critically engage and question the AES and its contemporary framing and potential reframing and continued impact on the BSMFs development. This was conducted through a dialogical social learning process in partnership with diverse voices that cut across the contemporary agrarian landscape that included “universities, think tanks, vocational training providers, standards-setting agencies, trade associations that provide specialized training, education, information, research and technical support” (Porter, 2000, p.17). The data for the social learning dialogue process was generated through an iterative analysis of dialogical social learning workshops, focus groups and semi-structured interviews. The analysis focused on the framing (Chapters 2, 3, and 5) and reframing of the AES (Chapter 6). Through dynamic engagement within the knowledge hub (contextual social learning and literature), the study surfaces a potential alternative discourse that actively includes the BSMFs as a crucial component of the commercial sector AES as the analysis shows these are largely excluded. This alternative discourse occurred through dialogical interactions with all participants via a pro-actively constituted social learning process, enriched and deepened by literature as indicated above. Main recommendations of the study are: 1. The AES must be framed to address the holistic value chain of BSMFs to help address underlying policy dualism, 2. Public Private Partnerships are needed to support BSMFs development and these should adopt a social learning approach that is reflective of complex realities 3. There is need for better understanding of roles and contributions of stakeholders in the AES to avoid duplications. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-10
Tense and aspect in Xhosa
- Authors: Savić, Stefan
- Date: 2021-10-29
- Subjects: Xhosa language , Xhosa language Grammar , Xhosa language Semantics , Xhosa language Tense , Xhosa language Aspect , Xhosa language Syntax , Xhosa language Morphology , Xhosa language Grammar, Comparative , Information structure
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192897 , vital:45277 , 10.21504/10962/192897
- Description: This dissertation investigates the semantics of each tense and aspect in Xhosa. Since tense and aspect perform important pragmatic functions, the analysis takes into account the correlation between the verb and the wider discourse in which it is embedded. Tense reflects the temporal relation between the time of the utterance (speech time) and an interval the speaker makes the assertion about (reference time). The Remote Past and the Remote Future tenses differ from their Recent/Immediate counterparts in that they denote events which occurred in a significantly different situation than the speech time and/or events in the surrounding discourse. Aspect does not only indicate the relation between the time occupied by the real world event and the reference time chosen by the speaker. The Perfective aspect represents an event as a unique change-of-state that pertains to a single point on the timeline which at the same time functions as the reference time. By contrast, for the Imperfective aspect temporally links the event to a contextually provided reference time, e.g. the utterance time, a time adverbial, a period of time previously introduced in the preceding discourse, or the interlocutors’ shared experience. At the pragmatic level, the Perfective aspect tends to introduce an event’s resulting state into the discourse, whereas the Imperfective aspect tends to rule it out. Like the Imperfective aspect, the Anterior and the Prospective aspects assert an event’s occurrence from a contextually defined reference time. They refer to the consequent and the preparatory states of an event, respectively. On the pragmatic level, the Anterior aspect may also indicate that the truth-conditionality of the event’s resulting state is contradicted in the immediate discourse. This study shows that tense and aspect temporally represent different means of temporally assigning an event to a particular portion of the timeline. I further argue that aspect indicates whether the reference time is provided in the context (Imperfective, Anterior, Prospective) or whether it is introduced by the verb itself (Perfective). Furthermore, this study shows that aspect exhibits a pragmatic function by laying focus on different parts of the event that are relevant in the upcoming discourse. , Thesis (PhD) -- Faculty of Humanities, Linguistics and Applied Languages Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Savić, Stefan
- Date: 2021-10-29
- Subjects: Xhosa language , Xhosa language Grammar , Xhosa language Semantics , Xhosa language Tense , Xhosa language Aspect , Xhosa language Syntax , Xhosa language Morphology , Xhosa language Grammar, Comparative , Information structure
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/192897 , vital:45277 , 10.21504/10962/192897
- Description: This dissertation investigates the semantics of each tense and aspect in Xhosa. Since tense and aspect perform important pragmatic functions, the analysis takes into account the correlation between the verb and the wider discourse in which it is embedded. Tense reflects the temporal relation between the time of the utterance (speech time) and an interval the speaker makes the assertion about (reference time). The Remote Past and the Remote Future tenses differ from their Recent/Immediate counterparts in that they denote events which occurred in a significantly different situation than the speech time and/or events in the surrounding discourse. Aspect does not only indicate the relation between the time occupied by the real world event and the reference time chosen by the speaker. The Perfective aspect represents an event as a unique change-of-state that pertains to a single point on the timeline which at the same time functions as the reference time. By contrast, for the Imperfective aspect temporally links the event to a contextually provided reference time, e.g. the utterance time, a time adverbial, a period of time previously introduced in the preceding discourse, or the interlocutors’ shared experience. At the pragmatic level, the Perfective aspect tends to introduce an event’s resulting state into the discourse, whereas the Imperfective aspect tends to rule it out. Like the Imperfective aspect, the Anterior and the Prospective aspects assert an event’s occurrence from a contextually defined reference time. They refer to the consequent and the preparatory states of an event, respectively. On the pragmatic level, the Anterior aspect may also indicate that the truth-conditionality of the event’s resulting state is contradicted in the immediate discourse. This study shows that tense and aspect temporally represent different means of temporally assigning an event to a particular portion of the timeline. I further argue that aspect indicates whether the reference time is provided in the context (Imperfective, Anterior, Prospective) or whether it is introduced by the verb itself (Perfective). Furthermore, this study shows that aspect exhibits a pragmatic function by laying focus on different parts of the event that are relevant in the upcoming discourse. , Thesis (PhD) -- Faculty of Humanities, Linguistics and Applied Languages Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
Exploring the political economy of the broadcast and distribution of the Mzansi Super League in South Africa
- Authors: Pettitt, Stephen John
- Date: 2021-10-29
- Subjects: Cricket Political aspects South Africa , Discrimination in sports South Africa , South Africa Social conditions , South Africa Economic conditions , Broadcasting South Africa , Cricket South Africa (Organization) , Television broadcasting of sports , Free-to-air broadcasting (FTA) South Africa , Mzansi Super League
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192308 , vital:45215
- Description: This thesis is a critical political economy analysis of the role played by the broadcast and distribution of the Mzansi Super League (MSL), a T20 cricket tournament in South Africa, in the transformation project of Cricket South Africa (CSA). The case study methodology is based on the four-leaf clover framework developed by Ruth Teer-Tomaselli. Cricket in South Africa is often viewed as a white and middle-class dominated sport, and CSA has been mandated to redress the historical racially segregated sport through a transformation agenda that focuses on changing the demographics of cricket. This paper investigates how the broadcast of a cricket tournament like the MSL on a Public Service Broadcaster (PSB) can have a positive effect on transformation due to the increased access and wider distribution. The broadcast regulations acknowledge this, as is seen in the introduction of ICASA draft regulations seeking to make more sport available on PSBs. The South African sports broadcast landscape is dominated by MultiChoice’s SuperSport, which has acquired a monopoly on sports broadcasting. The South African Broadcast Corporation (SABC) cannot compete, given its financial difficulties. A fall-out between CSA and SuperSport meant the SABC broadcast the MSL tournament, which lost CSA revenue but gained it a bigger audience. This thesis uses lived experiences and examples to illustrate that despite a financial loss, the wider media distribution of cricket will have positive effects on transformation that could counter the financial loss, especially if CSA creates new streams of income so that it relies less on broadcast revenue. In the current climate, however, compounded by internal financial and management issues, CSA cannot afford to forego the revenue from a private broadcaster and thus has no choice but to pursue a deal with a private broadcaster and lose out on the potential benefits of a wider audience. , Thesis (MA) -- Faculty of Humanities, Journalism and Media Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Pettitt, Stephen John
- Date: 2021-10-29
- Subjects: Cricket Political aspects South Africa , Discrimination in sports South Africa , South Africa Social conditions , South Africa Economic conditions , Broadcasting South Africa , Cricket South Africa (Organization) , Television broadcasting of sports , Free-to-air broadcasting (FTA) South Africa , Mzansi Super League
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192308 , vital:45215
- Description: This thesis is a critical political economy analysis of the role played by the broadcast and distribution of the Mzansi Super League (MSL), a T20 cricket tournament in South Africa, in the transformation project of Cricket South Africa (CSA). The case study methodology is based on the four-leaf clover framework developed by Ruth Teer-Tomaselli. Cricket in South Africa is often viewed as a white and middle-class dominated sport, and CSA has been mandated to redress the historical racially segregated sport through a transformation agenda that focuses on changing the demographics of cricket. This paper investigates how the broadcast of a cricket tournament like the MSL on a Public Service Broadcaster (PSB) can have a positive effect on transformation due to the increased access and wider distribution. The broadcast regulations acknowledge this, as is seen in the introduction of ICASA draft regulations seeking to make more sport available on PSBs. The South African sports broadcast landscape is dominated by MultiChoice’s SuperSport, which has acquired a monopoly on sports broadcasting. The South African Broadcast Corporation (SABC) cannot compete, given its financial difficulties. A fall-out between CSA and SuperSport meant the SABC broadcast the MSL tournament, which lost CSA revenue but gained it a bigger audience. This thesis uses lived experiences and examples to illustrate that despite a financial loss, the wider media distribution of cricket will have positive effects on transformation that could counter the financial loss, especially if CSA creates new streams of income so that it relies less on broadcast revenue. In the current climate, however, compounded by internal financial and management issues, CSA cannot afford to forego the revenue from a private broadcaster and thus has no choice but to pursue a deal with a private broadcaster and lose out on the potential benefits of a wider audience. , Thesis (MA) -- Faculty of Humanities, Journalism and Media Studies, 2021
- Full Text:
- Date Issued: 2021-10-29
In silico identification of natural inhibitory compounds against the Mycobacterium tuberculosis Enzyme Pyrazinamidase using high-throughput virtual screening techniques
- Authors: Kenyon, Thomas
- Date: 2021-10-29
- Subjects: Mycobacterium tuberculosis , Pyrazinamide , Molecular dynamics , High throughput screening (Drug development) , Mutagenesis , South African Natural Compounds database (SANCDB)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192074 , vital:45193
- Description: Tuberculosis (TB) is most commonly a pulmonary infection caused by the bacterium Mycobacterium tuberculosis. With the exception of the COVID-19 pandemic, TB was the most common cause of death due to an infectious disease for a number of years up until 2020. In 2019, 10 million people fell ill with TB worldwide and 1.4 million people died (WHO, 2020a). Additionally, multidrug-resistant TB (MDR-TB) remains a public health crisis and a health security threat. A global total of 206 030 people with multidrug- or rifampicin-resistant TB (MDR/RR-TB) were reported in 2019, a 10% increase from 186 883 in 2018. South Africa is ranked among the 48 high TB burden countries, with an estimated 360 000 people falling ill in 2019, resulting in 58 000 deaths, the majority of which being among people living with HIV. Unlike HIV, however, TB is a curable disease when managed correctly with long durations of antitubercular chemotherapy. Pyrazinamide (PZA) is an important first-line tuberculosis drug unique for its activity against latent TB. PZA is a prodrug, being converted into its active form, pyrazinoic acid (POA) by the Mtb gene pncA, coding for the pyrazinamidase enzyme (PZase). TB resistance to first-line drugs such as PZA is commonly associated with mutations in the pncA/PZase enzyme. This study aimed to identify potential novel inhibitors that bind to the active site of PZase. By making use of molecular docking studies and molecular dynamics (MD) simulations, high throughput virtual screening was performed on 623 compounds from the South African Natural Compounds database (SANCDB; https://sancdb.rubi.ru.ac.za). Ligands that selectively bound to the PZase active site were identified using docking studies, followed by MD simulations to assess ligand-PZase complex stability, Finally, hit compounds identified from the first round of MD simulations were screened again against PZase structures with high confidence point mutations known to infer PZA resistance in order to identify any novel compounds which had inhibitory potential against both WT and mutant forms of the PZase enzyme. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Kenyon, Thomas
- Date: 2021-10-29
- Subjects: Mycobacterium tuberculosis , Pyrazinamide , Molecular dynamics , High throughput screening (Drug development) , Mutagenesis , South African Natural Compounds database (SANCDB)
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192074 , vital:45193
- Description: Tuberculosis (TB) is most commonly a pulmonary infection caused by the bacterium Mycobacterium tuberculosis. With the exception of the COVID-19 pandemic, TB was the most common cause of death due to an infectious disease for a number of years up until 2020. In 2019, 10 million people fell ill with TB worldwide and 1.4 million people died (WHO, 2020a). Additionally, multidrug-resistant TB (MDR-TB) remains a public health crisis and a health security threat. A global total of 206 030 people with multidrug- or rifampicin-resistant TB (MDR/RR-TB) were reported in 2019, a 10% increase from 186 883 in 2018. South Africa is ranked among the 48 high TB burden countries, with an estimated 360 000 people falling ill in 2019, resulting in 58 000 deaths, the majority of which being among people living with HIV. Unlike HIV, however, TB is a curable disease when managed correctly with long durations of antitubercular chemotherapy. Pyrazinamide (PZA) is an important first-line tuberculosis drug unique for its activity against latent TB. PZA is a prodrug, being converted into its active form, pyrazinoic acid (POA) by the Mtb gene pncA, coding for the pyrazinamidase enzyme (PZase). TB resistance to first-line drugs such as PZA is commonly associated with mutations in the pncA/PZase enzyme. This study aimed to identify potential novel inhibitors that bind to the active site of PZase. By making use of molecular docking studies and molecular dynamics (MD) simulations, high throughput virtual screening was performed on 623 compounds from the South African Natural Compounds database (SANCDB; https://sancdb.rubi.ru.ac.za). Ligands that selectively bound to the PZase active site were identified using docking studies, followed by MD simulations to assess ligand-PZase complex stability, Finally, hit compounds identified from the first round of MD simulations were screened again against PZase structures with high confidence point mutations known to infer PZA resistance in order to identify any novel compounds which had inhibitory potential against both WT and mutant forms of the PZase enzyme. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-10-29
The de novo biosynthesis of biotin is required for the optimal growth of Salmonella enterica serovar Typhimurium in the intracellular environment
- Authors: McLaughlin, Claire
- Date: 2021-10-29
- Subjects: Salmonella , Biotin , Biosynthesis , Salmonella typhimurium , Antibacterial agents , Anti-infective agents , Pathogenic bacteria , Salmonella food poisoning
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192097 , vital:45195
- Description: Salmonella enterica serovar Typhimurium (S. Typhimurium) is a foodborne pathogen infecting humans and animals, contributing to significant morbidity and mortality worldwide each year. The increase in antibiotic-resistant S. Typhimurium infections in recent years has highlighted the need for new antibacterial drugs and drug targets. S. Typhimurium can acquire biotin through de novo biosynthesis or via transport from its extracellular environment. The importance of the vitamin for bacterial survival, coupled with the absence of the biotin biosynthetic pathway in humans, makes the biotin biosynthetic enzymes attractive targets for drug discovery. The study's primary aim was to determine the relative importance of the biotin biosynthesis and transport pathways for the in vitro and ex vivo growth and survival of S. Typhimurium, with the goal of validating the pathways as valid targets for antimicrobial drug development. In order to achieve this aim, we generated S. Typhimurium mutant strains harbouring deletions in either the biotin biosynthetic gene, bioB, or putative high-affinity biotin transporter, yigM (ΔbioB and ΔyigM, respectively), as well as a double mutant in which the two mutations were combined (ΔbioB ΔyigM). Since the simultaneous disruption of biotin biosynthesis and transport in the double mutant may form a synthetic lethal combination, preventing further analysis of the strain, we also constructed a conditional mutant in which the promoter of the yigM gene was replaced by the arabinose-regulatable, PBAD promoter in the ΔbioB background (ΔbioB PBAD::yigM). Since the expression of the YigM in this strain is arabinose-regulatable, its role as a biotin transporter can be evaluated by altering the arabinose concentration in the growth media. Once the mutant strains were isolated and verified genetically, their growth and that of their genetically complemented counterparts were analysed in liquid and/or solid M9 minimal medium in the absence of biotin. Consistent with previous observations, the ΔbioB auxotrophic mutant's growth was severely compromised in minimal media in the absence of biotin. The growth of the strain could, however, be restored by supplementation with exogenous biotin or expression of the wild type bioB gene from an episomal plasmid. The ability of biotin to reverse the growth defect of the ΔbioB mutant strain was, however, dependent on the presence of a functional YigM, since biotin supplementation did not affect the growth of the ΔbioB ΔyigM double mutant strain. The introduction of a second copy of the yigM gene in the ΔbioB ΔyigM background, however, restored the growth of the strain in the presence, but not absence, of biotin. The dependence of the double mutant on both YigM and biotin for growth supports the idea that the protein functions as the sole or primary biotin transporter in S. Typhimurium, as it has recently been shown for E. coli (Ringsletter, 2010; Finkenwirth et al, 2013). The essentiality of YigM for biotin transport was subsequently verified by two independent means. Firstly, the growth of the ΔbioB PBAD::yigM promoter-replacement mutant was strictly dependent on the inclusion of arabinose in biotin-supplemented M9 minimal media supplemented, indicating that the expression of YigM from the PBAD promoter is essential for biotin transport. Secondly, following treatment with a known small-molecule inhibitor of the biotin biosynthesis, MAC-13772, exogenous biotin was capable of restoring the growth defect of the YigM+ wild type S. Typhimurium strain, but not the YigM− ΔyigM mutant. Taken together, these findings confirm that YigM serves as the biotin transporter for S. Typhimurium and that the corresponding ΔyigM mutant is, as a result, defective for biotin transport. Having confirmed the genotypes and phenotypes of the ΔbioB, ΔyigM, and ΔbioB ΔyigM mutants, we next analysed the importance of the biotin biosynthesis and transport pathways for the growth and survival of S. Typhimurium within the intracellular environment. To this end, we determined the proliferation of each of the mutant strains following infection of HeLa epithelial and RAW264.7 macrophage-like cell lines. Our results revealed that the de novo biosynthesis of biotin is required for the optimal growth of S. Typhimurium following infection of both epithelial and macrophage-like cell lines. Disruption of biotin transport, by contrast, had no significant effect on the intracellular proliferation of S. Typhimurium when a functional pathway for the biosynthesis of biotin was present. The simultaneous disruption of biotin biosynthesis and transport, however, resulted in significant attenuation of S. Typhimurium in epithelial cells, while bacterial survival in macrophages decreased to below the limit of detection. Overall, our results suggest the S. Typhimurium relies primarily on biotin produced by the de novo biosynthesis pathway to support its growth in the intracellular environment. While YigM-mediated biotin transport is essential for sustaining the viability of intracellular S. Typhimurium in the absence of de novo biosynthesis, it appears to play a relatively minor role in the acquisition of biotin during growth in the nutrient-limited Salmonella containing vacuole. Our findings suggest that inhibiting biotin biosynthesis may be a viable strategy for combating systemic infections caused by Salmonella, as has been recently proposed for other medically important bacterial pathogens (Carfrae et al., 2020). , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: McLaughlin, Claire
- Date: 2021-10-29
- Subjects: Salmonella , Biotin , Biosynthesis , Salmonella typhimurium , Antibacterial agents , Anti-infective agents , Pathogenic bacteria , Salmonella food poisoning
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192097 , vital:45195
- Description: Salmonella enterica serovar Typhimurium (S. Typhimurium) is a foodborne pathogen infecting humans and animals, contributing to significant morbidity and mortality worldwide each year. The increase in antibiotic-resistant S. Typhimurium infections in recent years has highlighted the need for new antibacterial drugs and drug targets. S. Typhimurium can acquire biotin through de novo biosynthesis or via transport from its extracellular environment. The importance of the vitamin for bacterial survival, coupled with the absence of the biotin biosynthetic pathway in humans, makes the biotin biosynthetic enzymes attractive targets for drug discovery. The study's primary aim was to determine the relative importance of the biotin biosynthesis and transport pathways for the in vitro and ex vivo growth and survival of S. Typhimurium, with the goal of validating the pathways as valid targets for antimicrobial drug development. In order to achieve this aim, we generated S. Typhimurium mutant strains harbouring deletions in either the biotin biosynthetic gene, bioB, or putative high-affinity biotin transporter, yigM (ΔbioB and ΔyigM, respectively), as well as a double mutant in which the two mutations were combined (ΔbioB ΔyigM). Since the simultaneous disruption of biotin biosynthesis and transport in the double mutant may form a synthetic lethal combination, preventing further analysis of the strain, we also constructed a conditional mutant in which the promoter of the yigM gene was replaced by the arabinose-regulatable, PBAD promoter in the ΔbioB background (ΔbioB PBAD::yigM). Since the expression of the YigM in this strain is arabinose-regulatable, its role as a biotin transporter can be evaluated by altering the arabinose concentration in the growth media. Once the mutant strains were isolated and verified genetically, their growth and that of their genetically complemented counterparts were analysed in liquid and/or solid M9 minimal medium in the absence of biotin. Consistent with previous observations, the ΔbioB auxotrophic mutant's growth was severely compromised in minimal media in the absence of biotin. The growth of the strain could, however, be restored by supplementation with exogenous biotin or expression of the wild type bioB gene from an episomal plasmid. The ability of biotin to reverse the growth defect of the ΔbioB mutant strain was, however, dependent on the presence of a functional YigM, since biotin supplementation did not affect the growth of the ΔbioB ΔyigM double mutant strain. The introduction of a second copy of the yigM gene in the ΔbioB ΔyigM background, however, restored the growth of the strain in the presence, but not absence, of biotin. The dependence of the double mutant on both YigM and biotin for growth supports the idea that the protein functions as the sole or primary biotin transporter in S. Typhimurium, as it has recently been shown for E. coli (Ringsletter, 2010; Finkenwirth et al, 2013). The essentiality of YigM for biotin transport was subsequently verified by two independent means. Firstly, the growth of the ΔbioB PBAD::yigM promoter-replacement mutant was strictly dependent on the inclusion of arabinose in biotin-supplemented M9 minimal media supplemented, indicating that the expression of YigM from the PBAD promoter is essential for biotin transport. Secondly, following treatment with a known small-molecule inhibitor of the biotin biosynthesis, MAC-13772, exogenous biotin was capable of restoring the growth defect of the YigM+ wild type S. Typhimurium strain, but not the YigM− ΔyigM mutant. Taken together, these findings confirm that YigM serves as the biotin transporter for S. Typhimurium and that the corresponding ΔyigM mutant is, as a result, defective for biotin transport. Having confirmed the genotypes and phenotypes of the ΔbioB, ΔyigM, and ΔbioB ΔyigM mutants, we next analysed the importance of the biotin biosynthesis and transport pathways for the growth and survival of S. Typhimurium within the intracellular environment. To this end, we determined the proliferation of each of the mutant strains following infection of HeLa epithelial and RAW264.7 macrophage-like cell lines. Our results revealed that the de novo biosynthesis of biotin is required for the optimal growth of S. Typhimurium following infection of both epithelial and macrophage-like cell lines. Disruption of biotin transport, by contrast, had no significant effect on the intracellular proliferation of S. Typhimurium when a functional pathway for the biosynthesis of biotin was present. The simultaneous disruption of biotin biosynthesis and transport, however, resulted in significant attenuation of S. Typhimurium in epithelial cells, while bacterial survival in macrophages decreased to below the limit of detection. Overall, our results suggest the S. Typhimurium relies primarily on biotin produced by the de novo biosynthesis pathway to support its growth in the intracellular environment. While YigM-mediated biotin transport is essential for sustaining the viability of intracellular S. Typhimurium in the absence of de novo biosynthesis, it appears to play a relatively minor role in the acquisition of biotin during growth in the nutrient-limited Salmonella containing vacuole. Our findings suggest that inhibiting biotin biosynthesis may be a viable strategy for combating systemic infections caused by Salmonella, as has been recently proposed for other medically important bacterial pathogens (Carfrae et al., 2020). , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Date Issued: 2021-10-29
Quantifying the ecological and socioeconomic implications of a recovery/collapse of South Africa’s West Coast rock lobster fishery
- Authors: Eggers, Jessica Marguerite
- Date: 2021-10
- Subjects: Jasus lalandii South Africa , Lobster fisheries South Africa , Lobster fisheries Catch effort South Africa , Fishery management South Africa , Small-scale fisheries South Africa , Economics Sociological aspects , Value chain analysis
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188854 , vital:44792
- Description: The West Coast rock lobster (WCRL) Jasus lalandii fishery is South Africa’s third most valuable fishery, but the stock is currently at less than 2% of its pristine biomass. Scientists are warning that if no measures are taken, the WCRL could face commercial extinction. The necessary reductions in the global Total allowable Catch (TAC) seen in past years have had large economic implications for the WCRL value chain, but research into the socio-economic aspects of this fishery is limited. This study, therefore, aims to establish an overview of the economic revenue over the seasons 2016/17 – 2018/19 by exploring changes and trends in the net seasonal income (NSI) for the fishery, sectors within the fishery and different stakeholders. It also investigates the prospects for the sectors and different actors in this fishery over the seasons 2019/2020 - 2030/31 through analysis of the net present value (NPV) under three proposed global TAC management scenarios (global TAC of 640 tonnes, 1084 tonnes and 1280 tonnes). Data concerning costs and incomes as well as dynamics, mechanisms and concerns surrounding the fishery were collected from stakeholders in the different sectors through interviews and surveys. Further, official records from DEFF (catches, actors, vessels and quotas) and projections made by the Marine Resource Assessment (MARAM) team at the University of Cape Town (rates of recovery of the resource and future catches under the different TAC scenarios) were obtained and analysed. Cost and income data were summarised and models characterising the economic flows within the fishery were created. Calculations regarding the NSI and NPV were made using Monte Carlo simulations to account for the uncertainty surrounding many of the input variables. Results show that while the fishery as a whole made economic profits for the three seasons, the decreasing quotas in 2018/19 had a disproportionately negative impact on some of the representative individuals examined within the different sectors. The projections indicate that while each of the sectors as a whole would continue to make profits largely proportional to their allocation under the different TAC scenarios, many vessel owners in the fishery are likely to face economic losses or very marginal gains under the lower quota options, while the NPV for quota holders who outsource the catching of their quota are likely to be proportionally less affected by the changes in global TAC. This dynamic is important to consider for the future of this fishery. If the resource is to recover, and fishing activity is to continue equitably under the decreased quotas that the recovery of the biomass necessitates, the socio-economic context and the dynamics within which the fishers operate must be considered and studied more extensively and socio-economic consequences of a lower global TAC mitigated while improving the ecological status of the resource. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Eggers, Jessica Marguerite
- Date: 2021-10
- Subjects: Jasus lalandii South Africa , Lobster fisheries South Africa , Lobster fisheries Catch effort South Africa , Fishery management South Africa , Small-scale fisheries South Africa , Economics Sociological aspects , Value chain analysis
- Language: English
- Type: Masters theses , text
- Identifier: http://hdl.handle.net/10962/188854 , vital:44792
- Description: The West Coast rock lobster (WCRL) Jasus lalandii fishery is South Africa’s third most valuable fishery, but the stock is currently at less than 2% of its pristine biomass. Scientists are warning that if no measures are taken, the WCRL could face commercial extinction. The necessary reductions in the global Total allowable Catch (TAC) seen in past years have had large economic implications for the WCRL value chain, but research into the socio-economic aspects of this fishery is limited. This study, therefore, aims to establish an overview of the economic revenue over the seasons 2016/17 – 2018/19 by exploring changes and trends in the net seasonal income (NSI) for the fishery, sectors within the fishery and different stakeholders. It also investigates the prospects for the sectors and different actors in this fishery over the seasons 2019/2020 - 2030/31 through analysis of the net present value (NPV) under three proposed global TAC management scenarios (global TAC of 640 tonnes, 1084 tonnes and 1280 tonnes). Data concerning costs and incomes as well as dynamics, mechanisms and concerns surrounding the fishery were collected from stakeholders in the different sectors through interviews and surveys. Further, official records from DEFF (catches, actors, vessels and quotas) and projections made by the Marine Resource Assessment (MARAM) team at the University of Cape Town (rates of recovery of the resource and future catches under the different TAC scenarios) were obtained and analysed. Cost and income data were summarised and models characterising the economic flows within the fishery were created. Calculations regarding the NSI and NPV were made using Monte Carlo simulations to account for the uncertainty surrounding many of the input variables. Results show that while the fishery as a whole made economic profits for the three seasons, the decreasing quotas in 2018/19 had a disproportionately negative impact on some of the representative individuals examined within the different sectors. The projections indicate that while each of the sectors as a whole would continue to make profits largely proportional to their allocation under the different TAC scenarios, many vessel owners in the fishery are likely to face economic losses or very marginal gains under the lower quota options, while the NPV for quota holders who outsource the catching of their quota are likely to be proportionally less affected by the changes in global TAC. This dynamic is important to consider for the future of this fishery. If the resource is to recover, and fishing activity is to continue equitably under the decreased quotas that the recovery of the biomass necessitates, the socio-economic context and the dynamics within which the fishers operate must be considered and studied more extensively and socio-economic consequences of a lower global TAC mitigated while improving the ecological status of the resource. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2021
- Full Text:
- Date Issued: 2021-10
An analysis of technical efficiency and service effectiveness for freight railways in African and European countries
- Mfiyo, Azania https://orcid.org/0000-0002-0967-9756
- Authors: Mfiyo, Azania https://orcid.org/0000-0002-0967-9756
- Date: 2021-03
- Subjects: Freight and freightage , Railroads -- Freight
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20186 , vital:45406
- Description: For the past decades, technical efficiency and service effectiveness have become topical as performance measures in various sectors. However, a comparison of technical efficiency and service effectiveness for freight rail transport has received less attention in African and European countries. To address this challenge the current study seeks to analyse technical efficiency and service effectiveness of rail freight in African and European countries. Due to data unavailability in other countries, this study selected four African countries (South Africa, Morocco, Democratic Republic of Congo and Algeria) and four European countries (Lithuania, Austria, France and Germany). The data has been collected from the World Bank, International Union of Railway Statistics and Knoema for the period 2017. Input oriented and output oriented data envelope analysis (DEA) were used to analyze technical efficiency and service effectiveness, respectively. The application of DEA requires the selection of appropriate inputs, production and output variables. This study selected a number of employees and length of rail lines as input variables, gross train tonne kilometres (km) as production variable, tonnes carried and tonne kilometres (km) as output variables. The result shows that five out of eight countries were technical efficient and their services effective with values equal to 1.00. The Pearson correlation coefficient was used to analyse the relationship between technical efficiency and service effectiveness. The results indicate that there is a statistically significant positive correlation between technical efficiency and service effectiveness. To determine the impact exogenous variables on technical efficiency and service effectiveness, a Tobit regression analysis was conducted. The results show that technical efficiency and service effectiveness are not significantly affected by exogenous variables. On the other hand, technical efficiency is significantly affected by the number of employees while service effectiveness is significantly affected by gross train tonne km. This study recommends the use of less labour intensive assets and monitoring of gross train tonne km should be viewed as important strategies to improve technical efficiency and service effectiveness, respectively. , Thesis (MCom) -- Faculty of Management and Commerce, 2021
- Full Text:
- Date Issued: 2021-03
- Authors: Mfiyo, Azania https://orcid.org/0000-0002-0967-9756
- Date: 2021-03
- Subjects: Freight and freightage , Railroads -- Freight
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20186 , vital:45406
- Description: For the past decades, technical efficiency and service effectiveness have become topical as performance measures in various sectors. However, a comparison of technical efficiency and service effectiveness for freight rail transport has received less attention in African and European countries. To address this challenge the current study seeks to analyse technical efficiency and service effectiveness of rail freight in African and European countries. Due to data unavailability in other countries, this study selected four African countries (South Africa, Morocco, Democratic Republic of Congo and Algeria) and four European countries (Lithuania, Austria, France and Germany). The data has been collected from the World Bank, International Union of Railway Statistics and Knoema for the period 2017. Input oriented and output oriented data envelope analysis (DEA) were used to analyze technical efficiency and service effectiveness, respectively. The application of DEA requires the selection of appropriate inputs, production and output variables. This study selected a number of employees and length of rail lines as input variables, gross train tonne kilometres (km) as production variable, tonnes carried and tonne kilometres (km) as output variables. The result shows that five out of eight countries were technical efficient and their services effective with values equal to 1.00. The Pearson correlation coefficient was used to analyse the relationship between technical efficiency and service effectiveness. The results indicate that there is a statistically significant positive correlation between technical efficiency and service effectiveness. To determine the impact exogenous variables on technical efficiency and service effectiveness, a Tobit regression analysis was conducted. The results show that technical efficiency and service effectiveness are not significantly affected by exogenous variables. On the other hand, technical efficiency is significantly affected by the number of employees while service effectiveness is significantly affected by gross train tonne km. This study recommends the use of less labour intensive assets and monitoring of gross train tonne km should be viewed as important strategies to improve technical efficiency and service effectiveness, respectively. , Thesis (MCom) -- Faculty of Management and Commerce, 2021
- Full Text:
- Date Issued: 2021-03
Curriculum adjustment and adaptive leadership in two service-learning courses at Rhodes University as a consequence of the COVID-19 pandemic
- Authors: Khuhlane, Heide Nozuko
- Date: 2021-10-29
- Subjects: COVID-19 (Disease) , Curriculum planning South Africa Makhanda , Rhodes University , Service learning South Africa Makhanda , Educational leadership South Africa Makhanda , Educational change South Africa Makhanda , Adaptive leadership
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191192 , vital:45069
- Description: The COVID-19 global pandemic altered many aspects of learning. Learning through service, a component of community engagement in higher education linking academic learning and the community was no exception. Informed by Experiential Learning Theory, this study investigated the curriculum adjustment of two service-learning courses at Rhodes University and the leadership development of those who lead the courses as a consequence of COVID-19. The study’s initial goal was to highlight the position of service-learning as a component of academic learning. With the onset of the COVID-19 pandemic the goal was extended to understanding the impact of the pandemic not only on service-learning, but on leadership as well. Furthermore, the study sought to determine the responsiveness of service-learning policies at Rhodes University at a time of crisis. The study was designed as an interpretivist case study with four participants and one secondary participant. The study employed document analysis, individual interviews and a focus group interview to collect data. Data analysis took the form of content analysis and coding, through the lens of Experiential Learning Theory and an alternative service-based model. The study findings revealed that as a result of the COVID-19 global pandemic both service-learning courses had to be adapted to ensure successful completion. The adaptations included attention to scaffolded learning, assessment and course outcomes; in one course the service engagement aspect with the community was lost entirely to ensure the saftey of students through adherence to COVID-19 safety regulations. The study also found that the participants developed adaptive leadership competencies and skills, technological and collaboration skills as well as a heightened regard for pastoral care and social justice. However, it was evident that the pandemic revealed gaps in the conceptual understanding of service-learning in the context of the two courses, a need for responsive policy, and practical strategies to implement those policies in smaller units in the institution. The study thus recommends an alternative service-based model approach to service-learning, increased policy responsiveness to issues posed by the ‘new normal’ to support adaptive leadership development, re-defining of the university-community partnership and the identification of opportunities for innovation and collaboration intra-departmentally through service-learning. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Khuhlane, Heide Nozuko
- Date: 2021-10-29
- Subjects: COVID-19 (Disease) , Curriculum planning South Africa Makhanda , Rhodes University , Service learning South Africa Makhanda , Educational leadership South Africa Makhanda , Educational change South Africa Makhanda , Adaptive leadership
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191192 , vital:45069
- Description: The COVID-19 global pandemic altered many aspects of learning. Learning through service, a component of community engagement in higher education linking academic learning and the community was no exception. Informed by Experiential Learning Theory, this study investigated the curriculum adjustment of two service-learning courses at Rhodes University and the leadership development of those who lead the courses as a consequence of COVID-19. The study’s initial goal was to highlight the position of service-learning as a component of academic learning. With the onset of the COVID-19 pandemic the goal was extended to understanding the impact of the pandemic not only on service-learning, but on leadership as well. Furthermore, the study sought to determine the responsiveness of service-learning policies at Rhodes University at a time of crisis. The study was designed as an interpretivist case study with four participants and one secondary participant. The study employed document analysis, individual interviews and a focus group interview to collect data. Data analysis took the form of content analysis and coding, through the lens of Experiential Learning Theory and an alternative service-based model. The study findings revealed that as a result of the COVID-19 global pandemic both service-learning courses had to be adapted to ensure successful completion. The adaptations included attention to scaffolded learning, assessment and course outcomes; in one course the service engagement aspect with the community was lost entirely to ensure the saftey of students through adherence to COVID-19 safety regulations. The study also found that the participants developed adaptive leadership competencies and skills, technological and collaboration skills as well as a heightened regard for pastoral care and social justice. However, it was evident that the pandemic revealed gaps in the conceptual understanding of service-learning in the context of the two courses, a need for responsive policy, and practical strategies to implement those policies in smaller units in the institution. The study thus recommends an alternative service-based model approach to service-learning, increased policy responsiveness to issues posed by the ‘new normal’ to support adaptive leadership development, re-defining of the university-community partnership and the identification of opportunities for innovation and collaboration intra-departmentally through service-learning. , Thesis (MEd) -- Faculty of Education, Education, 2021
- Full Text:
- Date Issued: 2021-10-29
Climate change and small-scale farmer livelihood adaptation in rural border communities in Southern Africa: A case study of Ezondweni Village in Mchinji, Malawi
- Authors: Simango, Kennedy Khuzwayo
- Date: 2021-10-29
- Subjects: Farms, Small Malawi Mchinji , Climatic changes Economic aspects Malawi Mchinji , Climatic changes Risk management Malawi Mchinji , Crops and climate Malawi Mchinji , Sustainable agriculture Malawi Mchinji , Farmers Social networks Malawi Mchinji , Farm income Malawi Mchinji
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190008 , vital:44955
- Description: Southern Africa is a region increasingly experiencing the detrimental effects of climate change and variability. The rural areas in particular face unprecedented climate change-induced challenges in relation to small-scale farmers being able to pursue household-based livelihoods, and these farmers seek ways of adapting to climate change and variability in doing so. Some rural communities exist along territorial borders and their attempts at adapting to climate change entails cross-border networks and activities. In this context, this thesis examines small-scale farmer adaptation to climate change and variability in the small village of Ezondweni in Malawi near the Zambian border. Analytically, the study draws upon the Sustainable Livelihoods Framework as well as social network theory and the theory of reflexive agency put forward by Margaret Archer. A qualitative research design entailed informal interviews with a small number of Ezondweni villagers, focusing on their perceptions of climate change and their practices of climate change adaptation. The study demonstrates the diverse activities pursued by villagers, both within Malawi and beyond, in seeking to maintain household-based livelihoods, as well as the significance of mutually-supportive social networks which facilitate these livelihood processes. , Thesis (MSocSci) -- Faculty of Humanities, Social Science, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Simango, Kennedy Khuzwayo
- Date: 2021-10-29
- Subjects: Farms, Small Malawi Mchinji , Climatic changes Economic aspects Malawi Mchinji , Climatic changes Risk management Malawi Mchinji , Crops and climate Malawi Mchinji , Sustainable agriculture Malawi Mchinji , Farmers Social networks Malawi Mchinji , Farm income Malawi Mchinji
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190008 , vital:44955
- Description: Southern Africa is a region increasingly experiencing the detrimental effects of climate change and variability. The rural areas in particular face unprecedented climate change-induced challenges in relation to small-scale farmers being able to pursue household-based livelihoods, and these farmers seek ways of adapting to climate change and variability in doing so. Some rural communities exist along territorial borders and their attempts at adapting to climate change entails cross-border networks and activities. In this context, this thesis examines small-scale farmer adaptation to climate change and variability in the small village of Ezondweni in Malawi near the Zambian border. Analytically, the study draws upon the Sustainable Livelihoods Framework as well as social network theory and the theory of reflexive agency put forward by Margaret Archer. A qualitative research design entailed informal interviews with a small number of Ezondweni villagers, focusing on their perceptions of climate change and their practices of climate change adaptation. The study demonstrates the diverse activities pursued by villagers, both within Malawi and beyond, in seeking to maintain household-based livelihoods, as well as the significance of mutually-supportive social networks which facilitate these livelihood processes. , Thesis (MSocSci) -- Faculty of Humanities, Social Science, 2021
- Full Text:
- Date Issued: 2021-10-29
Ecological infrastructure importance for drought mitigation in rural South African catchments: the Cacadu Catchment case example
- Authors: Xoxo, Beauten Sinetemba
- Date: 2021-10
- Subjects: Sustainable Development Goals , Water security South Africa , Remote sensing , Watershed restoration South Africa , Restoration ecology South Africa , Ecosystem services South Africa , SDG 15.3.1
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191203 , vital:45070
- Description: Water scarcity is recognised as one of the significant challenges facing many countries, including South Africa. The threat of water scarcity is exacerbated by the coupled impacts of climate and anthropogenic drivers. Ongoing droughts and continued land cover change and degradation influence the ability of catchments to partition rainwater runoff, thereby affecting streamflow returns. However, quantifying land degradation accurately remains a challenge. This thesis used the theoretical lens of investing in ecological infrastructure to improve the drought mitigation function in rural catchments. This theoretical framework allows for a social-ecological systems approach to understand and facilitate science-based strategies for promoting ecosystem recovery. Specifically, this study aimed to explore the role and benefit of ecological infrastructure for improving drought mitigation, and consequently, water security for rural communities. Thus, this study sought to assess the consequences of human actions to catchment health status using the 15th Sustainable Development Goal indicator for the proportion of degraded land over the total land area as a surrogate. Secondly, hydrological modelling was used to describe how different land covers influence catchment hydrology, which related to how ecological infrastructure enables drought risk-reduction for mitigation regulation. Finally, this study developed a spatial prioritisation plan for restoration to improve drought mitigation for four focal ecological infrastructure (EI) categories (i.e. wetlands, riparian margins, abandoned agricultural fields and grasslands). The focal EI categories were selected for their importance in delivering water-related ecosystem services when sustainably managed. Chapter 1 sets the scene (i.e. provides the study background) and Chapter 2 provides a review of the literature. In Chapter 3, the recently released global GIS toolbox (TRENDS.EARTH) was used for tracking land change and for assessing the SDG 15.3.1 degradation indicator of i.e. Cacadu catchment over 15 years at a 300 m resolution. The results showed a declining trend in biomass productivity within the Cacadu catchment led to moderate degradation, with 16.79% of the total landscape degraded, which was determined by the pugin using the one-out, all-out rule. The incidence of degradation was detected in middle reaches of the catchment (i.e. S10F-J), while some improvement was detected in upper reaches (S10A-C) and lower reaches (S10J). In Chapter 4, a GIS-based Analytic Hierarchical Process (AHP) based on community stakeholder priorities, open-access spatial datasets and expert opinions, was used to identify EI focal areas that are best suitable for restoration to increase the drought mitigation capacity of the Cacadu catchment. The collected datasets provided three broad criteria (ecosystem health, water provision and social benefit) for establishing the AHP model using 12 spatial attributes. Prioritisation results show that up to 89% of the Cacadu catchment is suitable for restoration to improve drought mitigation. Catchments S10B-D, and S10F, S10G and S10J were highly prioritised while S10A, S10E and S10H received low priority, due to improving environmental conditions and low hydrological potential. Areas that were prioritised with consideration for local livelihoods overlap the areas for drought mitigation and form a network of villages from the middle to lower catchment reaches. Prioritised restoration areas with a consideration of societal benefit made up 0.56% of wetlands, 4.27% of riparian margins, 92.06% of abandoned croplands, and 51.86% of grasslands. Chapter 5 reports on use of the Pitman groundwater model to help understand the influence of land modification on catchment hydrology, and highlight the role of restoration interventions. The Cacadu catchment is ungauged, therefore the neighbouring Indwe catchment was used for parameter transfer through a spatial regionalisation technique. Results suggest that degradation increases surface runoff and aggravates recharge reduction, thereby reducing streamflow during low flow periods. In areas where there is natural land cover recovery, the Pitman Model simulated similar dry season streamflow to the natural land cover. Combining the outcomes from the three assessments allowed the study to highlight the role and benefits of ecological infrastructure in terms of drought mitigation. Study findings were interpreted to make recommendations for the role and benefit of ecological infrastructure for drought mitigation at a landscape scale and tertiary catchment level, within the context of available management options. The results support the notion that multiple science data sources can promote investments in ecological infrastructure. However, better spatial and temporal resolution datasets at a national level are still needed to improve the accuracy of studies such as the one outlined in this thesis. The study recommends adopting better ecosystem protection approaches and collaborative governance at multiple levels to reduce the vulnerability of rural communities to drought impacts. , Thesis (MSc) -- Faculty of Science, Institute for Water Research, 2021
- Full Text:
- Date Issued: 2021-10
- Authors: Xoxo, Beauten Sinetemba
- Date: 2021-10
- Subjects: Sustainable Development Goals , Water security South Africa , Remote sensing , Watershed restoration South Africa , Restoration ecology South Africa , Ecosystem services South Africa , SDG 15.3.1
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/191203 , vital:45070
- Description: Water scarcity is recognised as one of the significant challenges facing many countries, including South Africa. The threat of water scarcity is exacerbated by the coupled impacts of climate and anthropogenic drivers. Ongoing droughts and continued land cover change and degradation influence the ability of catchments to partition rainwater runoff, thereby affecting streamflow returns. However, quantifying land degradation accurately remains a challenge. This thesis used the theoretical lens of investing in ecological infrastructure to improve the drought mitigation function in rural catchments. This theoretical framework allows for a social-ecological systems approach to understand and facilitate science-based strategies for promoting ecosystem recovery. Specifically, this study aimed to explore the role and benefit of ecological infrastructure for improving drought mitigation, and consequently, water security for rural communities. Thus, this study sought to assess the consequences of human actions to catchment health status using the 15th Sustainable Development Goal indicator for the proportion of degraded land over the total land area as a surrogate. Secondly, hydrological modelling was used to describe how different land covers influence catchment hydrology, which related to how ecological infrastructure enables drought risk-reduction for mitigation regulation. Finally, this study developed a spatial prioritisation plan for restoration to improve drought mitigation for four focal ecological infrastructure (EI) categories (i.e. wetlands, riparian margins, abandoned agricultural fields and grasslands). The focal EI categories were selected for their importance in delivering water-related ecosystem services when sustainably managed. Chapter 1 sets the scene (i.e. provides the study background) and Chapter 2 provides a review of the literature. In Chapter 3, the recently released global GIS toolbox (TRENDS.EARTH) was used for tracking land change and for assessing the SDG 15.3.1 degradation indicator of i.e. Cacadu catchment over 15 years at a 300 m resolution. The results showed a declining trend in biomass productivity within the Cacadu catchment led to moderate degradation, with 16.79% of the total landscape degraded, which was determined by the pugin using the one-out, all-out rule. The incidence of degradation was detected in middle reaches of the catchment (i.e. S10F-J), while some improvement was detected in upper reaches (S10A-C) and lower reaches (S10J). In Chapter 4, a GIS-based Analytic Hierarchical Process (AHP) based on community stakeholder priorities, open-access spatial datasets and expert opinions, was used to identify EI focal areas that are best suitable for restoration to increase the drought mitigation capacity of the Cacadu catchment. The collected datasets provided three broad criteria (ecosystem health, water provision and social benefit) for establishing the AHP model using 12 spatial attributes. Prioritisation results show that up to 89% of the Cacadu catchment is suitable for restoration to improve drought mitigation. Catchments S10B-D, and S10F, S10G and S10J were highly prioritised while S10A, S10E and S10H received low priority, due to improving environmental conditions and low hydrological potential. Areas that were prioritised with consideration for local livelihoods overlap the areas for drought mitigation and form a network of villages from the middle to lower catchment reaches. Prioritised restoration areas with a consideration of societal benefit made up 0.56% of wetlands, 4.27% of riparian margins, 92.06% of abandoned croplands, and 51.86% of grasslands. Chapter 5 reports on use of the Pitman groundwater model to help understand the influence of land modification on catchment hydrology, and highlight the role of restoration interventions. The Cacadu catchment is ungauged, therefore the neighbouring Indwe catchment was used for parameter transfer through a spatial regionalisation technique. Results suggest that degradation increases surface runoff and aggravates recharge reduction, thereby reducing streamflow during low flow periods. In areas where there is natural land cover recovery, the Pitman Model simulated similar dry season streamflow to the natural land cover. Combining the outcomes from the three assessments allowed the study to highlight the role and benefits of ecological infrastructure in terms of drought mitigation. Study findings were interpreted to make recommendations for the role and benefit of ecological infrastructure for drought mitigation at a landscape scale and tertiary catchment level, within the context of available management options. The results support the notion that multiple science data sources can promote investments in ecological infrastructure. However, better spatial and temporal resolution datasets at a national level are still needed to improve the accuracy of studies such as the one outlined in this thesis. The study recommends adopting better ecosystem protection approaches and collaborative governance at multiple levels to reduce the vulnerability of rural communities to drought impacts. , Thesis (MSc) -- Faculty of Science, Institute for Water Research, 2021
- Full Text:
- Date Issued: 2021-10
Pessimism and the secular problem of evil
- Authors: Ruiters, Siphamandla
- Date: 2021-10-29
- Subjects: Good and evil , Pessimism , Optimism , Secularism , Quality of life
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190111 , vital:44964
- Description: How should we respond to the prevalence of ubiquitous evil? In this thesis, I present two responses to the secular problem of evil. The secular problem of evil exists because we want to live good lives, but we are all existentially vulnerable to evil. Consequently, we can think of various ways in which evil's existence poses a problem for us. When faced with such evil, I distinguish two responses that we may adopt, namely, optimistic or pessimistic responses to the secular problem of evil. These responses may be understood as stances that we may adopt about the relative evil and goodness in the world. Once I have made a thorough evaluation of the discussion around the secular problem of evil and the responses, I will suggest that pessimism is an appealing and appropriate response that we should adopt. To achieve the aims of this thesis, I will first clarify the kind of evil at stake in this thesis and then explain how philosophers have historically responded to this problem. Secondly, I will focus on the contemporary discussion on the secular problem of evil and show the responses are optimistic responses. Finally, I will provide a case against optimism and then show why pessimism is the most appealing and appropriate response. , Thesis (MA) -- Faculty of Humanities, Philosophy, 2021
- Full Text:
- Date Issued: 2021-10-29
- Authors: Ruiters, Siphamandla
- Date: 2021-10-29
- Subjects: Good and evil , Pessimism , Optimism , Secularism , Quality of life
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/190111 , vital:44964
- Description: How should we respond to the prevalence of ubiquitous evil? In this thesis, I present two responses to the secular problem of evil. The secular problem of evil exists because we want to live good lives, but we are all existentially vulnerable to evil. Consequently, we can think of various ways in which evil's existence poses a problem for us. When faced with such evil, I distinguish two responses that we may adopt, namely, optimistic or pessimistic responses to the secular problem of evil. These responses may be understood as stances that we may adopt about the relative evil and goodness in the world. Once I have made a thorough evaluation of the discussion around the secular problem of evil and the responses, I will suggest that pessimism is an appealing and appropriate response that we should adopt. To achieve the aims of this thesis, I will first clarify the kind of evil at stake in this thesis and then explain how philosophers have historically responded to this problem. Secondly, I will focus on the contemporary discussion on the secular problem of evil and show the responses are optimistic responses. Finally, I will provide a case against optimism and then show why pessimism is the most appealing and appropriate response. , Thesis (MA) -- Faculty of Humanities, Philosophy, 2021
- Full Text:
- Date Issued: 2021-10-29
Assessing the invasive status and reproductive ecology of two Crataegus species in South Africa; Crataegus monogyna Jacq and C. mexicana DC
- Authors: Tshilingalinga, Sydney
- Date: 2021-03
- Subjects: Crataegus monogyna , Nonindigenous pests , Biological invasions
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20904 , vital:46740
- Description: In South Africa different species, from the genus Crataegus, including Crataegus monogyna Jacq and C. mexicana DC have been introduced for various reasons in the past. Populations of these plants have now established in multiple provinces. However, the invasive status, risk and insect pollinators that promote their reproduction and dispersal have never been studied in South Africa. This study was aimed at 1) Assessing the risk of, and mapping two Crataegus species, Crataegus monogyna Jacq and C. mexicana DC in South Africa, 2) Determining the role and effectiveness of insects pollinators to fruiting of C. monogyna and C. mexicana, 3) Identifying flower visitors of C. monogyna and C. mexicana, and 4) documenting potential dispersal vectors for both species in the Eastern Cape Province. A framework entitled “Framework and guideline for conducting risk analysis under NEM: BA Alien and Invasive Species Regulation of 2014” was used to assess the risk of the two Crataegus spp, and we conducted field trips to various provinces in SA to map their distribution. The author conducted an exclusion experiment to determine the role and effectiveness of insect pollinators. Observations were conducted to identify flower visitors and potential dispersal vectors for both species. The risk analysis results suggested that both species pose a high risk of becoming invasive in South Africa. The eradication feasibility of both species was found to be medium with C. monogyna having an eradication feasibility score of 5 and C. mexicana having an eradication feasibility score of 4. This meant that there was a 50 percent chance for both species to be eradicated in South Africa currently. After a thorough risk analysis, it was recommended that both species be listed under category 1b on the National Environmental Management Biodiversity Act. Category 1b species are invasive species that need to be controlled, and if possible, they must be eradicated, trading of species from this category is not allowed. Crataegus mexicana was found to be widespread in South Africa with ten relatively small populations distributed in 5 provinces; Limpopo, Mpumalanga, KwaZulu-Natal, Free State and Eastern Cape Province. Crataegus monogyna was found not to be widespread in South Africa, with only three populations found in the Eastern Cape Province. Insect pollinators contribute to the fruiting of both species in SA. However, the exotic plants were also observed to be able to self-pollinate when insects are excluded. Flowers of C. monogyna were visited by various insect species from orders Lepidoptera, Hymenoptera, Coleoptera and Diptera, while C. mexicana is visited by species from the order Hymenoptera, Diptera, Lepidoptera and Coleoptera. Seventy-seven percent (77 percent) of potential dispersal vectors observed for C. monogyna were birds, and 15 percent were mammals. For C. mexicana, 71 percent of potential dispersal vectors observed were mammals, and 29 percent were birds. Crataegus monogyna and C. mexicana are emerging invasive alien species in South Africa, and not much is known about them. Although the two species are listed as invasive weeds in South Africa, very little is known about their invasive status in other parts of the world. This study has managed to give baseline information and data about both species which are already in South Africa. The baseline information and data include the population structure of both species, their distribution, the risk they pose to South Africa biodiversity and their reproduction ecology. Currently, there are no management plans in place for both species in South Africa, and this is because they are not listed yet in the National Environmental Management Biodiversity Act of South Africa. However, this study recommends that current populations continue to be monitored, awareness of both species in various provinces be initiated to help in the discovery of new and emerging populations, and management options of large populations developed in the future. , Thesis (MSc) (Entomology) -- University of Fort Hare, 2021
- Full Text:
- Date Issued: 2021-03
- Authors: Tshilingalinga, Sydney
- Date: 2021-03
- Subjects: Crataegus monogyna , Nonindigenous pests , Biological invasions
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/20904 , vital:46740
- Description: In South Africa different species, from the genus Crataegus, including Crataegus monogyna Jacq and C. mexicana DC have been introduced for various reasons in the past. Populations of these plants have now established in multiple provinces. However, the invasive status, risk and insect pollinators that promote their reproduction and dispersal have never been studied in South Africa. This study was aimed at 1) Assessing the risk of, and mapping two Crataegus species, Crataegus monogyna Jacq and C. mexicana DC in South Africa, 2) Determining the role and effectiveness of insects pollinators to fruiting of C. monogyna and C. mexicana, 3) Identifying flower visitors of C. monogyna and C. mexicana, and 4) documenting potential dispersal vectors for both species in the Eastern Cape Province. A framework entitled “Framework and guideline for conducting risk analysis under NEM: BA Alien and Invasive Species Regulation of 2014” was used to assess the risk of the two Crataegus spp, and we conducted field trips to various provinces in SA to map their distribution. The author conducted an exclusion experiment to determine the role and effectiveness of insect pollinators. Observations were conducted to identify flower visitors and potential dispersal vectors for both species. The risk analysis results suggested that both species pose a high risk of becoming invasive in South Africa. The eradication feasibility of both species was found to be medium with C. monogyna having an eradication feasibility score of 5 and C. mexicana having an eradication feasibility score of 4. This meant that there was a 50 percent chance for both species to be eradicated in South Africa currently. After a thorough risk analysis, it was recommended that both species be listed under category 1b on the National Environmental Management Biodiversity Act. Category 1b species are invasive species that need to be controlled, and if possible, they must be eradicated, trading of species from this category is not allowed. Crataegus mexicana was found to be widespread in South Africa with ten relatively small populations distributed in 5 provinces; Limpopo, Mpumalanga, KwaZulu-Natal, Free State and Eastern Cape Province. Crataegus monogyna was found not to be widespread in South Africa, with only three populations found in the Eastern Cape Province. Insect pollinators contribute to the fruiting of both species in SA. However, the exotic plants were also observed to be able to self-pollinate when insects are excluded. Flowers of C. monogyna were visited by various insect species from orders Lepidoptera, Hymenoptera, Coleoptera and Diptera, while C. mexicana is visited by species from the order Hymenoptera, Diptera, Lepidoptera and Coleoptera. Seventy-seven percent (77 percent) of potential dispersal vectors observed for C. monogyna were birds, and 15 percent were mammals. For C. mexicana, 71 percent of potential dispersal vectors observed were mammals, and 29 percent were birds. Crataegus monogyna and C. mexicana are emerging invasive alien species in South Africa, and not much is known about them. Although the two species are listed as invasive weeds in South Africa, very little is known about their invasive status in other parts of the world. This study has managed to give baseline information and data about both species which are already in South Africa. The baseline information and data include the population structure of both species, their distribution, the risk they pose to South Africa biodiversity and their reproduction ecology. Currently, there are no management plans in place for both species in South Africa, and this is because they are not listed yet in the National Environmental Management Biodiversity Act of South Africa. However, this study recommends that current populations continue to be monitored, awareness of both species in various provinces be initiated to help in the discovery of new and emerging populations, and management options of large populations developed in the future. , Thesis (MSc) (Entomology) -- University of Fort Hare, 2021
- Full Text:
- Date Issued: 2021-03