The depositional history and evaluation of two late quaternary, diamondiferous pocket beaches, south-western Namibia
- Authors: Milad, Micael George
- Date: 2004-03
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/420934 , vital:71795
- Description: The two Late Quaternary, diamondiferous pocket beach deposits studied here are situated along a 10 km stretch of the storm-dominated, Atlantic coastline of the Sperrgebiet, south-western Namibia. The pocket beaches are approximately 130 km north of the Orange River mouth, which is widely accepted as a long-lived point source for diamonds sourced from the interior of southern Africa. A total of fourteen pocket beach deposits were recently evaluated in this area, but only two of these, namely Site 2 (to the south) and Site 3 (to the north), are considered here. The main diamondbearing horizons are beach gravels, which occur within, and form part of, the pocket beach sequences. The beach gravels are mostly blanketed by sand overburden, meaning that exposures available for study were limited, and much reliance was placed on borehole logging and observations of evaluation sample tailings. The main aims are to unravel the depositional history of the pocket beach sequences, identify the controls on diamond mineralisation in the beach gravels, and critically examine two different methods of estimating average diamond size for the deposits. In pursuit of these aims, sedimentological characteristics of the unconsolidated pocket beach deposits were recorded using small diameter drill holes, hydraulic grab bulk samples, trench exposures and surface outcrops. The surface geology, geomorphology and modern wave patterns were mapped using high-resolution, Airborne Laser Survey imagery coupled with extensive field checking. Three-dimensional geological modeling software was used to gain insight into the subsurface morphology of the deposits. Fossil shell samples were used to aid interpretation of ancient depositional environments and to date parts of the pocket beach sequences. Variations in diamond concentration and the size of diamonds were recorded using bulk samples, some of which were taken from a trench, but most of which were excavated using a hydraulic grab tool called the GB50. Finally, by using diamond size data from Site 3, sample data from diamondiferous beach gravels to the south of the study area and sample campaign simulations, two alternative methods of evaluating average diamond size in marine gravel deposits were appraised.The pocket beach sequences occur within north-south trending valleys of a major deflation basin and are separated from one another by rocky headlands. The ridge-and-valley topography of the deflation basin has resulted from differential erosion of Late Proterozoic basement rock units, alternating layers of which differ greatly in their resistance to the long-lived, local denudationalprocesses. On the basis of the stratigraphic information collected from the unconsolidated pocket beach valley fills, interpreted within the context of global, Late Pleistocene sea level records, the following depositional history is deduced : a) Deposition of sheetflood gravels by ephemeral streams, activated during a regressive phase. b) Transgression, culminating in the deposition of a gravel beach, representing a sea level highstand of +4 metres above mean sea level (mamsl) at between 120 000 and 130 000 BP. c)A regressive phase, resulting in deflation of former valley fills to the bedrock valley floor and accompanied by re-activation of ephemeral stream activity to form sheetflood deposits; this represents a protracted period of subaerial exposure of the +4 m gravel beach deposit. d) Deposition of a great volume of sediment in the valleys during the latter stages of the transgression from the Last Glacial Maximum (LGM). The sequence generated during this phase, which started at ca. 9 000 BP, contains : i) pan/coastal sabkha sediments, ii) shallow, sheltered bay sediments, iii) back-barrier lagoonal sediments, iv) a gravel beach deposit representing a sea level stillstand at -5 mamsl, laid down between 7 600 and 5 600 BP, v) another gravel beach deposit representing the well-known Middle Holocene sea level highstand at +2 to +3 mamsl, laid down at ca. 5 000 BP, and which terminated the transgression from the LGM. e) A minor regression to the current sea level, accompanied by progradation of the shoreline to its current position. This progradational marine unit consists almost entirely of sand and grit, reflecting the lack of gravel supply to this part of the coastline in the most recent past. f) Deposition of modern coastal dunes, which cap the pocket beach sequence and are the youngest sediments in the study area. Using trench and hydraulic grab evaluation sample results, in combination with analysis of wave patterns and field observations, the following local controls on the density distribution (ie. concentration) and size distribution of diamonds in the gravel beach deposits (+4, -5 and +2 to +3 mamsl stands) are recognised: a) Gravel beach depositional processes, which are responsible for clast sorting on the beach, have influenced the density and size distribution of diamonds. The infill zone, or beach toe, favours maximum diamond concentration while diamond size decreases from the imbricate zone (intertidal) to the infill zone (subtidal). b) Wave energy is identified as the dominant local control on diamond size distribution, but has also influenced diamond concentration to a limited degree. Larger diamonds are intimately associated with coarser beach gravels, both of which are a reflection of increased wave energy. Higher concentrations of diamonds are sometimes associated with zones of coarser gravel and therefore greater wave energy. c) The time of deposition of the host gravel beach is seen to be the dominant controlling factor with respect to diamond concentration. This is seen as evidence of significant temporal variation in the availability of diamonds in the littoral evironment. A significant reduction (20%) in average diamond size from Site 2 to Site 3, over a distance of only 6 km, is evident. The following were identified as reasons for this reduction in diamond size : a) Longshore sorting processes, of which the long-lived northerly littoral drift is a key part, are known to have played a role in the diminution of diamond size northwards from the Orange River mouth point source. However, it is believed that this can only partly account for the observed 20% reduction in diamond size. b) Input of sediment and smaller diamonds at Site 3, reworked out of an older, Eocene-aged marine succession in the hinterland, is recognised as a possible additional reason for the large reduction in diamond size from Site 2 to Site 3. It is also speculated that the large size of the pocket beach at Site 3, relative to Site 2, may have resulted in lower average wave energy at Site 3, with consequent reduced average diamond size. Diamond size in the beach gravels of Site 3, as well as in beach gravels elsewhere in the Sperrgebiet, is seen to be lognormally-distributed within geologically homogeneous zones. In theory, lognormal mean estimators represent the best method of estimating average diamond size in such cases, whereas the arithmetic mean estimator has the tendency to overestimate when large outlier values occur. Lognormal mean estimators have the added benefit of providing for the calculation of confidence limits, which are becoming increasingly more important as financial lending institutions insist on better quantification of the risk involved in resource estimates. Sample campaign simulations demonstrate, for the kinds of diamond size-frequency distributions typical of beach gravel deposits at Site 3, that there is no significant improvement in the accuracy of average diamond size estimates when lognormal mean estimators are used instead of the arithmetic mean estimator. This is because the variance (a ) of the diamond populations is low, and large outlier values are extremely unlikely to occur. However, simulation of a diamond population with high variance, drawn from a sample of beach gravels near the Orange River mouth, shows that lognormal estimators produce significantly more accurate results when a is large. Since individual diamond weights were not recorded during evaluation sampling of Site 3, numerical solution of lognormal estimators is not possible, and these would need to be solved using a less accurate graphical method. It is therefore recommended that individual diamond weights are recorded in future sampling campaigns, allowing for the use of lognormal mean estimators, and the calculation of confidence limits for average diamond size estimates. , Thesis (MSc) -- Science, Geology, 2004
- Full Text:
- Authors: Milad, Micael George
- Date: 2004-03
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/420934 , vital:71795
- Description: The two Late Quaternary, diamondiferous pocket beach deposits studied here are situated along a 10 km stretch of the storm-dominated, Atlantic coastline of the Sperrgebiet, south-western Namibia. The pocket beaches are approximately 130 km north of the Orange River mouth, which is widely accepted as a long-lived point source for diamonds sourced from the interior of southern Africa. A total of fourteen pocket beach deposits were recently evaluated in this area, but only two of these, namely Site 2 (to the south) and Site 3 (to the north), are considered here. The main diamondbearing horizons are beach gravels, which occur within, and form part of, the pocket beach sequences. The beach gravels are mostly blanketed by sand overburden, meaning that exposures available for study were limited, and much reliance was placed on borehole logging and observations of evaluation sample tailings. The main aims are to unravel the depositional history of the pocket beach sequences, identify the controls on diamond mineralisation in the beach gravels, and critically examine two different methods of estimating average diamond size for the deposits. In pursuit of these aims, sedimentological characteristics of the unconsolidated pocket beach deposits were recorded using small diameter drill holes, hydraulic grab bulk samples, trench exposures and surface outcrops. The surface geology, geomorphology and modern wave patterns were mapped using high-resolution, Airborne Laser Survey imagery coupled with extensive field checking. Three-dimensional geological modeling software was used to gain insight into the subsurface morphology of the deposits. Fossil shell samples were used to aid interpretation of ancient depositional environments and to date parts of the pocket beach sequences. Variations in diamond concentration and the size of diamonds were recorded using bulk samples, some of which were taken from a trench, but most of which were excavated using a hydraulic grab tool called the GB50. Finally, by using diamond size data from Site 3, sample data from diamondiferous beach gravels to the south of the study area and sample campaign simulations, two alternative methods of evaluating average diamond size in marine gravel deposits were appraised.The pocket beach sequences occur within north-south trending valleys of a major deflation basin and are separated from one another by rocky headlands. The ridge-and-valley topography of the deflation basin has resulted from differential erosion of Late Proterozoic basement rock units, alternating layers of which differ greatly in their resistance to the long-lived, local denudationalprocesses. On the basis of the stratigraphic information collected from the unconsolidated pocket beach valley fills, interpreted within the context of global, Late Pleistocene sea level records, the following depositional history is deduced : a) Deposition of sheetflood gravels by ephemeral streams, activated during a regressive phase. b) Transgression, culminating in the deposition of a gravel beach, representing a sea level highstand of +4 metres above mean sea level (mamsl) at between 120 000 and 130 000 BP. c)A regressive phase, resulting in deflation of former valley fills to the bedrock valley floor and accompanied by re-activation of ephemeral stream activity to form sheetflood deposits; this represents a protracted period of subaerial exposure of the +4 m gravel beach deposit. d) Deposition of a great volume of sediment in the valleys during the latter stages of the transgression from the Last Glacial Maximum (LGM). The sequence generated during this phase, which started at ca. 9 000 BP, contains : i) pan/coastal sabkha sediments, ii) shallow, sheltered bay sediments, iii) back-barrier lagoonal sediments, iv) a gravel beach deposit representing a sea level stillstand at -5 mamsl, laid down between 7 600 and 5 600 BP, v) another gravel beach deposit representing the well-known Middle Holocene sea level highstand at +2 to +3 mamsl, laid down at ca. 5 000 BP, and which terminated the transgression from the LGM. e) A minor regression to the current sea level, accompanied by progradation of the shoreline to its current position. This progradational marine unit consists almost entirely of sand and grit, reflecting the lack of gravel supply to this part of the coastline in the most recent past. f) Deposition of modern coastal dunes, which cap the pocket beach sequence and are the youngest sediments in the study area. Using trench and hydraulic grab evaluation sample results, in combination with analysis of wave patterns and field observations, the following local controls on the density distribution (ie. concentration) and size distribution of diamonds in the gravel beach deposits (+4, -5 and +2 to +3 mamsl stands) are recognised: a) Gravel beach depositional processes, which are responsible for clast sorting on the beach, have influenced the density and size distribution of diamonds. The infill zone, or beach toe, favours maximum diamond concentration while diamond size decreases from the imbricate zone (intertidal) to the infill zone (subtidal). b) Wave energy is identified as the dominant local control on diamond size distribution, but has also influenced diamond concentration to a limited degree. Larger diamonds are intimately associated with coarser beach gravels, both of which are a reflection of increased wave energy. Higher concentrations of diamonds are sometimes associated with zones of coarser gravel and therefore greater wave energy. c) The time of deposition of the host gravel beach is seen to be the dominant controlling factor with respect to diamond concentration. This is seen as evidence of significant temporal variation in the availability of diamonds in the littoral evironment. A significant reduction (20%) in average diamond size from Site 2 to Site 3, over a distance of only 6 km, is evident. The following were identified as reasons for this reduction in diamond size : a) Longshore sorting processes, of which the long-lived northerly littoral drift is a key part, are known to have played a role in the diminution of diamond size northwards from the Orange River mouth point source. However, it is believed that this can only partly account for the observed 20% reduction in diamond size. b) Input of sediment and smaller diamonds at Site 3, reworked out of an older, Eocene-aged marine succession in the hinterland, is recognised as a possible additional reason for the large reduction in diamond size from Site 2 to Site 3. It is also speculated that the large size of the pocket beach at Site 3, relative to Site 2, may have resulted in lower average wave energy at Site 3, with consequent reduced average diamond size. Diamond size in the beach gravels of Site 3, as well as in beach gravels elsewhere in the Sperrgebiet, is seen to be lognormally-distributed within geologically homogeneous zones. In theory, lognormal mean estimators represent the best method of estimating average diamond size in such cases, whereas the arithmetic mean estimator has the tendency to overestimate when large outlier values occur. Lognormal mean estimators have the added benefit of providing for the calculation of confidence limits, which are becoming increasingly more important as financial lending institutions insist on better quantification of the risk involved in resource estimates. Sample campaign simulations demonstrate, for the kinds of diamond size-frequency distributions typical of beach gravel deposits at Site 3, that there is no significant improvement in the accuracy of average diamond size estimates when lognormal mean estimators are used instead of the arithmetic mean estimator. This is because the variance (a ) of the diamond populations is low, and large outlier values are extremely unlikely to occur. However, simulation of a diamond population with high variance, drawn from a sample of beach gravels near the Orange River mouth, shows that lognormal estimators produce significantly more accurate results when a is large. Since individual diamond weights were not recorded during evaluation sampling of Site 3, numerical solution of lognormal estimators is not possible, and these would need to be solved using a less accurate graphical method. It is therefore recommended that individual diamond weights are recorded in future sampling campaigns, allowing for the use of lognormal mean estimators, and the calculation of confidence limits for average diamond size estimates. , Thesis (MSc) -- Science, Geology, 2004
- Full Text:
Labour law and non-standard employment: case studies of selected workplaces in Makhanda
- Authors: Mini, Sifanelwa
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/425171 , vital:72216
- Description: While precarious and poorly-regulated forms of employment are on the increase worldwide, the patterns vary significantly over time and space. This study sought to understand employees’ perceptions of non-standard employment (NSE), the reasons why employers resort to NSE and why they use particular types of NSE. In addition, the research explored how labour law protections for NSE are applied in particular workplaces. Drawing on the regulation approach, which provides a conceptual framework to explain changes in production and employment relationships under specific spatio-temporal conditions, this study focused on three companies in Makhanda. Furthermore, this study employed a qualitative research method to explore the employees’ perceptions on non-standard work. This was done by using an interpretive approach to explore how workers experience NSE and how Eastern Cape citizens in Makhanda navigate the scourge of unemployment and exploitation in the labour market. Moreover, the research investigated how employees experience the efficacy of their employment rights in the workplace. The employment rights observed in the study include (among others) leave, contract of employment and collective bargaining; all of which are provisions in the Labour Relations Act. The findings in the study do validate the use of NSE as a ‘tool’ to curb high unemployment. However, the study finds that the positive result of job creation does not signify job security for non-standard workers, instead beneath the rhetoric of job creation and investment, lies hidden the exploitation of vulnerable groups of citizens and extension of precarious forms of employment. This is because businesses engage in economic competition locally and globally. Therefore, in order to successfully compete against other, employer’s cut on labour expenses by adopting a “race to the bottom,” the effect of which is paying employees below the minimum wage. Moreover, this study opposes the argument that NSE is a stepping stone to permanent employment. The conditions which prevail in NSE are distinctly different from those in the Standard Employment Relationship (SER), making it difficult for employees to transition to a new labour market. The latter is more aligned with the heterodox approach than it is to the orthodox approach to labour market. , Thesis (MA) -- Faculty of Humanities, Sociology, 2023
- Full Text:
- Authors: Mini, Sifanelwa
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/425171 , vital:72216
- Description: While precarious and poorly-regulated forms of employment are on the increase worldwide, the patterns vary significantly over time and space. This study sought to understand employees’ perceptions of non-standard employment (NSE), the reasons why employers resort to NSE and why they use particular types of NSE. In addition, the research explored how labour law protections for NSE are applied in particular workplaces. Drawing on the regulation approach, which provides a conceptual framework to explain changes in production and employment relationships under specific spatio-temporal conditions, this study focused on three companies in Makhanda. Furthermore, this study employed a qualitative research method to explore the employees’ perceptions on non-standard work. This was done by using an interpretive approach to explore how workers experience NSE and how Eastern Cape citizens in Makhanda navigate the scourge of unemployment and exploitation in the labour market. Moreover, the research investigated how employees experience the efficacy of their employment rights in the workplace. The employment rights observed in the study include (among others) leave, contract of employment and collective bargaining; all of which are provisions in the Labour Relations Act. The findings in the study do validate the use of NSE as a ‘tool’ to curb high unemployment. However, the study finds that the positive result of job creation does not signify job security for non-standard workers, instead beneath the rhetoric of job creation and investment, lies hidden the exploitation of vulnerable groups of citizens and extension of precarious forms of employment. This is because businesses engage in economic competition locally and globally. Therefore, in order to successfully compete against other, employer’s cut on labour expenses by adopting a “race to the bottom,” the effect of which is paying employees below the minimum wage. Moreover, this study opposes the argument that NSE is a stepping stone to permanent employment. The conditions which prevail in NSE are distinctly different from those in the Standard Employment Relationship (SER), making it difficult for employees to transition to a new labour market. The latter is more aligned with the heterodox approach than it is to the orthodox approach to labour market. , Thesis (MA) -- Faculty of Humanities, Sociology, 2023
- Full Text:
The effects of exploitation on the activity of Chrysoblephus laticeps in a thermally variable environment
- Authors: Mlotshwa, Nonhle Thubelihle
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424346 , vital:72145
- Description: Embargoed. Expected release date 2025. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
- Authors: Mlotshwa, Nonhle Thubelihle
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424346 , vital:72145
- Description: Embargoed. Expected release date 2025. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
The enigmatic subterranean amphipod genus (sternophysinx: sternophysingidae): conservation and systematics
- Authors: Mlungu, Zizile
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424424 , vital:72152
- Description: Sternophysingidae Holsinger, 1992 is a monotypic subterranean amphipod family endemic to Namibia and South Africa. It currently has eight described species under the genus Sternophysinx. The species in this family are considered narrow endemics, having only been identified using morphological characters. However, the apparent wide distribution of certain species, reported in several subterranean waters in different provinces, suggests that our current taxonomic understanding of these species needs to be completed, thus needing revision. Further, detailed knowledge of the distribution and phylogenetic relationship between species of this taxon still needs to be improved. This study aimed to use integrative taxonomy to analyse both morphology and molecular biology to study hidden diversity and to further our understanding of the distribution in this taxon. The available morphological keys were used to identify species, and 12S rRNA was also used to investigate the relationships of Sternophysinx species and delimit species boundaries. The study primarily aimed to use mitochondrial cytochrome c oxidase subunit I (COI). However, due to technical issues such as getting the correct primers, this study's aims were altered, and 12S was used instead of CO1. However, the process of getting CO1 sequences is still ongoing, and the results will be made available elsewhere. The current study aimed to visit all the type localities of the seven species of Sternophysinx reported in South Africa, including all known localities in which these amphipods have been recorded in the past. Nevertheless, this study did not get samples from Nelspruit, De Hoop Nature Reserve, and Nash Nature Reserve, which cover type localities of S. travaleensis, Matlapitse and Chaos cave that harbours S. calceola. Instead, the current study added five new localities Graaff-Reinet, Beaufort West, Hogsback, Makhambathi Nature Reserve and Ntsikeni Nature Reserve, for the distribution, including two new provinces (i.e., Eastern Cape and KwaZulu-Natal) that had records of this genus in the country. Three delimitation methods, Assemble Species by Automatic Partitioning (ASAP), Bayesian implementation of the Poison Tree Processor (bPTP) and Automatic Barcode Gap Discovery (ABGD), were used to identify cryptic species within Sternophysinx. Phylogenetic analyses and three delimitation methods (ASAP, bPTP and ABGD) revealed considerable hidden cryptic diversity within this Sternophysinx. Preliminary morphological examination revealed at least two species as undescribed from Bakwena and Sterkfontein caves, and several that were morphologically identified using the current taxonomic keys did not match with the molecular analysis. For example, S. basilobata from three different systems, Boesmansgat cave (Northern Cape), Beaufort West (Western Cape) and Potchefstroom (North West), was in genetically different putative species. The same is true for S. robertsi and S. alca in Ficus and Peppercorn cave in Limpopo. Overall, the results of the current study demonstrate the need for a comprehensive integrative taxonomic revision of Sternophysinx. These findings suggest that S. basilobata is a complex of distinct lineages and requires further study. On the other hand, species delimitation methods suggested that there are 12- 14 candidate species (Figure 2.5). Lastly, this study investigated the threat posed by the invasive koi fish introduced to an important cave, Boesmansgat cave in the Northern Cape, which is a type locality of two endemic species (S. megacheles and S. basilobata). Stable isotope (δ13C and δ15N) and gut content analyses of the fish were investigated to establish whether this invasive fish feed on these critical creatures, thus endangering their long-term survival. Stable isotope signatures and the stomach gut content proved to be helpful in determining the diet of the koi fish, revealing it to be an omnivorous feeder with high invertebrate preference, including amphipods. These results indicate that the introduction of koi fish in the Boesmansgat cave threatens the long-term sustainability of these amphipods and other invertebrate assemblages in this cave. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2023
- Full Text:
- Authors: Mlungu, Zizile
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424424 , vital:72152
- Description: Sternophysingidae Holsinger, 1992 is a monotypic subterranean amphipod family endemic to Namibia and South Africa. It currently has eight described species under the genus Sternophysinx. The species in this family are considered narrow endemics, having only been identified using morphological characters. However, the apparent wide distribution of certain species, reported in several subterranean waters in different provinces, suggests that our current taxonomic understanding of these species needs to be completed, thus needing revision. Further, detailed knowledge of the distribution and phylogenetic relationship between species of this taxon still needs to be improved. This study aimed to use integrative taxonomy to analyse both morphology and molecular biology to study hidden diversity and to further our understanding of the distribution in this taxon. The available morphological keys were used to identify species, and 12S rRNA was also used to investigate the relationships of Sternophysinx species and delimit species boundaries. The study primarily aimed to use mitochondrial cytochrome c oxidase subunit I (COI). However, due to technical issues such as getting the correct primers, this study's aims were altered, and 12S was used instead of CO1. However, the process of getting CO1 sequences is still ongoing, and the results will be made available elsewhere. The current study aimed to visit all the type localities of the seven species of Sternophysinx reported in South Africa, including all known localities in which these amphipods have been recorded in the past. Nevertheless, this study did not get samples from Nelspruit, De Hoop Nature Reserve, and Nash Nature Reserve, which cover type localities of S. travaleensis, Matlapitse and Chaos cave that harbours S. calceola. Instead, the current study added five new localities Graaff-Reinet, Beaufort West, Hogsback, Makhambathi Nature Reserve and Ntsikeni Nature Reserve, for the distribution, including two new provinces (i.e., Eastern Cape and KwaZulu-Natal) that had records of this genus in the country. Three delimitation methods, Assemble Species by Automatic Partitioning (ASAP), Bayesian implementation of the Poison Tree Processor (bPTP) and Automatic Barcode Gap Discovery (ABGD), were used to identify cryptic species within Sternophysinx. Phylogenetic analyses and three delimitation methods (ASAP, bPTP and ABGD) revealed considerable hidden cryptic diversity within this Sternophysinx. Preliminary morphological examination revealed at least two species as undescribed from Bakwena and Sterkfontein caves, and several that were morphologically identified using the current taxonomic keys did not match with the molecular analysis. For example, S. basilobata from three different systems, Boesmansgat cave (Northern Cape), Beaufort West (Western Cape) and Potchefstroom (North West), was in genetically different putative species. The same is true for S. robertsi and S. alca in Ficus and Peppercorn cave in Limpopo. Overall, the results of the current study demonstrate the need for a comprehensive integrative taxonomic revision of Sternophysinx. These findings suggest that S. basilobata is a complex of distinct lineages and requires further study. On the other hand, species delimitation methods suggested that there are 12- 14 candidate species (Figure 2.5). Lastly, this study investigated the threat posed by the invasive koi fish introduced to an important cave, Boesmansgat cave in the Northern Cape, which is a type locality of two endemic species (S. megacheles and S. basilobata). Stable isotope (δ13C and δ15N) and gut content analyses of the fish were investigated to establish whether this invasive fish feed on these critical creatures, thus endangering their long-term survival. Stable isotope signatures and the stomach gut content proved to be helpful in determining the diet of the koi fish, revealing it to be an omnivorous feeder with high invertebrate preference, including amphipods. These results indicate that the introduction of koi fish in the Boesmansgat cave threatens the long-term sustainability of these amphipods and other invertebrate assemblages in this cave. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2023
- Full Text:
African linguistic phenomenology as illustrated through the Setswana language
- Authors: Modisakeng, Lemogang
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/425089 , vital:72208
- Description: Embargoed. Expected release date 2025. , Thesis (MA) -- Faculty of Humanities, Philosophy, 2023
- Full Text:
- Authors: Modisakeng, Lemogang
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/425089 , vital:72208
- Description: Embargoed. Expected release date 2025. , Thesis (MA) -- Faculty of Humanities, Philosophy, 2023
- Full Text:
Nurses’ experiences of an abortion counselling training course and their understandings of quality abortion services
- Authors: Mogonong, Laurah Carolina
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408862 , vital:70532
- Description: This research study focuses on nurses’ experiences of participating in an abortion counselling training programme in the Eastern Cape Province (E.C), using a grounded theory and symbolic interactionism framework. The study aims to investigate how participating in a women-centred abortion counselling training course offered through the Critical Studies in Sexualities and Reproduction research unit may modify or improve nurses’ practice of abortion counselling and understanding of quality abortion services. Through purposive sampling, nine research participants working as abortion providers in EC health care facilities were recruited. Research data were produced using discussions around prior abortion counselling experiences, a reflective activity, power point case presentations conducted within the counselling training, and semi-structured interviews conducted two months after the training with five of the providers. A grounded theory analysis was used to generate themes that highlighted different aspects that enabled or hindered access to quality abortion services. In accordance with prior research, it was revealed that nurses undergo abortion training but there is limited content on abortion counselling training. Findings from this study reveal the modifications of practice and understanding of quality abortion services of nurses who participated in the client-centred abortion counselling training course. Themes of change that emerged from the nurses’ experiences were rendering counselling services in a non- judgemental, non-directive way, being acknowledged and recognized for the services they offer as abortion providers, and accepting that abortion is a reproductive legal right that can be accessed whenever a woman in need of the service requests it. The findings of this research also indicate that, despite the controversy and stigma attached to providing abortion services, the participants were motivated to continue offering abortion services because they felt equipped since undergoing abortion counselling training. The training course improved reported abortion counselling practices, but systematic issues such as lack of managerial support, space for individual counselling and procedure equipment continue to undermine services. , Thesis (MA) -- Faculty of Humanities, Psychology, 2023
- Full Text:
- Authors: Mogonong, Laurah Carolina
- Date: 2023-03-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/408862 , vital:70532
- Description: This research study focuses on nurses’ experiences of participating in an abortion counselling training programme in the Eastern Cape Province (E.C), using a grounded theory and symbolic interactionism framework. The study aims to investigate how participating in a women-centred abortion counselling training course offered through the Critical Studies in Sexualities and Reproduction research unit may modify or improve nurses’ practice of abortion counselling and understanding of quality abortion services. Through purposive sampling, nine research participants working as abortion providers in EC health care facilities were recruited. Research data were produced using discussions around prior abortion counselling experiences, a reflective activity, power point case presentations conducted within the counselling training, and semi-structured interviews conducted two months after the training with five of the providers. A grounded theory analysis was used to generate themes that highlighted different aspects that enabled or hindered access to quality abortion services. In accordance with prior research, it was revealed that nurses undergo abortion training but there is limited content on abortion counselling training. Findings from this study reveal the modifications of practice and understanding of quality abortion services of nurses who participated in the client-centred abortion counselling training course. Themes of change that emerged from the nurses’ experiences were rendering counselling services in a non- judgemental, non-directive way, being acknowledged and recognized for the services they offer as abortion providers, and accepting that abortion is a reproductive legal right that can be accessed whenever a woman in need of the service requests it. The findings of this research also indicate that, despite the controversy and stigma attached to providing abortion services, the participants were motivated to continue offering abortion services because they felt equipped since undergoing abortion counselling training. The training course improved reported abortion counselling practices, but systematic issues such as lack of managerial support, space for individual counselling and procedure equipment continue to undermine services. , Thesis (MA) -- Faculty of Humanities, Psychology, 2023
- Full Text:
Along the river that flowed south
- Authors: Mohlomi, Teboho Samson
- Date: 2022-04-07
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/234195 , vital:50171
- Description: Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2022
- Full Text:
- Authors: Mohlomi, Teboho Samson
- Date: 2022-04-07
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/234195 , vital:50171
- Description: Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2022
- Full Text:
Characterizing shift systems and exploring their effects on sleep and fatigue in South African freight railway operators
- Authors: Mona, Chumani
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424300 , vital:72141
- Description: Embargoed. Expected release date 2025. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2023
- Full Text:
- Authors: Mona, Chumani
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424300 , vital:72141
- Description: Embargoed. Expected release date 2025. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2023
- Full Text:
A comparison of the self-esteem of black and white high school pupils
- Authors: Morrow, Brian Robert
- Date: 1988
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193033 , vital:45292
- Description: This study investigated the level of self-esteem of black and white high-school students using the Rosenberg self-esteem scale. One hundred and eighty six subjects were used, 63 of them being white while 118 were black. A validation of the Rosenberg scale for the black sample was attempted using a correlation between the scale score and a rating of the subjects by teachers. The results of the study showed no significant difference between the self-esteem levels, while the validation study failed to confirm the validity of the test for black subjects in South Africa. However, the validation study v/as rejected as inconclusive and the results of the comparison accepted as confirmatory of previous research. An incidental positive finding revealed that white males have higher self-esteem than white females,. The theory and past research of self-esteem comparisons between racial groups is reviewed. The conclusion is reached in this study that the concept of self-esteem has outlasted its usefulness in the field of comparisons between racial groups and research of a qualitative nature .can provide further data for the understanding of differences between racial groups. , Thesis (MA) -- Faculty of Humanities, Psychology, 1988
- Full Text:
- Authors: Morrow, Brian Robert
- Date: 1988
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193033 , vital:45292
- Description: This study investigated the level of self-esteem of black and white high-school students using the Rosenberg self-esteem scale. One hundred and eighty six subjects were used, 63 of them being white while 118 were black. A validation of the Rosenberg scale for the black sample was attempted using a correlation between the scale score and a rating of the subjects by teachers. The results of the study showed no significant difference between the self-esteem levels, while the validation study failed to confirm the validity of the test for black subjects in South Africa. However, the validation study v/as rejected as inconclusive and the results of the comparison accepted as confirmatory of previous research. An incidental positive finding revealed that white males have higher self-esteem than white females,. The theory and past research of self-esteem comparisons between racial groups is reviewed. The conclusion is reached in this study that the concept of self-esteem has outlasted its usefulness in the field of comparisons between racial groups and research of a qualitative nature .can provide further data for the understanding of differences between racial groups. , Thesis (MA) -- Faculty of Humanities, Psychology, 1988
- Full Text:
Composition portfolio
- Authors: Moss, Keith
- Date: 2007
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193724 , vital:45390
- Description: Whitacre's music is primarily diatonic with subtle modulations, where the new key is always preserved diatonicaliy as well. I refer to this style as expanded diatonicism. Examples in my work of expanded diatonicism within this portfolio are to be found in navem ad somnium, Wynken, Blynken and Nod, as well as Hymn for Brass. My applications of expanded diatonic practices within each of these works are discussed in a separate appendix within the body of this portfolio. That these works are vocal or have a vocal inspiration (Hymn for Brass) reveals the extent of my initial reaction to Whitacre's music during a choral rehearsal. Furthermore, in my vocal compositions especially I chose texts which frequently gravitate towards ideas related to water, the ocean and ships. Whilst water has a soothing and inspiring influence upon me, presumably evidenced in my expanded diatonicism, it also represents my journey and investigation into the sound work of Whitacre in particular. It may be noticed that many of my works in this portfolio have religious orientated themes. I am a Christian, and belong to a Berean 2 Congregational Church. Whilst I am not Catholic or Anglican, I nonetheless have made use of texts from the liturgy of these denominations, as they emphasise the basis of my Christian faith. Why I chose Hymn for Brass as a title could possibly be construed as a religious reference, however it was named after the piece was written, and had no theological connotations in its inception save for the hymnody style of the orchestration. Providence and The Eventide both have a Christian philosophical foundation which is explored in depth in the accompanying appendix. The latter work explores an extension of my expanded diatonic style through incorporating aspects of chromaticism. The rationale for this is dealt with in my discussion of this work. This portfolio represents an overview of my compositional activities to date and displays my growing confidence with the technical aspects of composition as well as my yearning for experimentation with new ideas and manners of expression. , Thesis (MMus) -- Faculty of Humanities, Music and Musicology, 2007
- Full Text:
- Authors: Moss, Keith
- Date: 2007
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/193724 , vital:45390
- Description: Whitacre's music is primarily diatonic with subtle modulations, where the new key is always preserved diatonicaliy as well. I refer to this style as expanded diatonicism. Examples in my work of expanded diatonicism within this portfolio are to be found in navem ad somnium, Wynken, Blynken and Nod, as well as Hymn for Brass. My applications of expanded diatonic practices within each of these works are discussed in a separate appendix within the body of this portfolio. That these works are vocal or have a vocal inspiration (Hymn for Brass) reveals the extent of my initial reaction to Whitacre's music during a choral rehearsal. Furthermore, in my vocal compositions especially I chose texts which frequently gravitate towards ideas related to water, the ocean and ships. Whilst water has a soothing and inspiring influence upon me, presumably evidenced in my expanded diatonicism, it also represents my journey and investigation into the sound work of Whitacre in particular. It may be noticed that many of my works in this portfolio have religious orientated themes. I am a Christian, and belong to a Berean 2 Congregational Church. Whilst I am not Catholic or Anglican, I nonetheless have made use of texts from the liturgy of these denominations, as they emphasise the basis of my Christian faith. Why I chose Hymn for Brass as a title could possibly be construed as a religious reference, however it was named after the piece was written, and had no theological connotations in its inception save for the hymnody style of the orchestration. Providence and The Eventide both have a Christian philosophical foundation which is explored in depth in the accompanying appendix. The latter work explores an extension of my expanded diatonic style through incorporating aspects of chromaticism. The rationale for this is dealt with in my discussion of this work. This portfolio represents an overview of my compositional activities to date and displays my growing confidence with the technical aspects of composition as well as my yearning for experimentation with new ideas and manners of expression. , Thesis (MMus) -- Faculty of Humanities, Music and Musicology, 2007
- Full Text:
Population dynamics, fire, and reproductive ecology of Oldenburgia grandis (Asteraceae), an unusual fynbos tree endemic to the Eastern Cape
- Authors: Mostert, Emma Charlotte
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365268 , vital:65722
- Description: Thesis embargoed. Possible release date set for early 2024. , Thesis (MSc) -- Faculty of Science, Botany, 2022
- Full Text:
- Authors: Mostert, Emma Charlotte
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365268 , vital:65722
- Description: Thesis embargoed. Possible release date set for early 2024. , Thesis (MSc) -- Faculty of Science, Botany, 2022
- Full Text:
Octa carboxy metal (II) phthalocyanine covalent films as pH sensitive electrochemical sensor for neurotransmitters
- Authors: Moyo, Iphithuli
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424525 , vital:72161
- Description: Octa acyl chloride metallophthalocyanines of cobalt (CoOAClPc) and iron (FeOAClPc) were synthesized and characterized using spectroscopic and electrochemical techniques. The metallophthalocyanines were fabricated as thin films onto phenylethylamine (PEA) pre-grafted Au electrode following a covalent amide reaction. The spectroscopic and electrochemical characterization confirmed the modification of the bare Au with PEA monolayer thin film (Au-PEA) and the covalent immobilization of MOAClPc to yield Au-PEA-MOAClPc (where M is Co and Fe). The acyl chloride functional groups were hydrolyzed forming pH sensitive thin films of terminal carboxylic acid (-COOH) functional groups (Au-PEA-MOCAPc). The Au-PEA-MOCAPc electrode exhibited pH selectivity and sensitivity properties towards the negatively charged [Fe(CN)6]3-/4- and positively charged [Ru(NH3)6]2+/3+ redox probes. The Au-PEA-MOCAPc electrodes were studied for their electrocatalytic and electroanalytical properties towards the detection of catecholamine neurotransmitters; dopamine (DA), epinephrine (EP) and norepinephrine (NOR). The electrodes were further investigated in the screening of ascorbic and uric acids by means of pH sensitive functional groups. The modification process exhibited good reproducibility. Excellent electrocatalytic and electroanalytical properties were observed. The limits of detection (LOD) determined using 3σ/m was found to be 64 nM, 0.22 μM and 0.17 μM for DA, EP and NOR respectively using Au-PEA-CoOCAPc. For Au-PEA-FeOCAPc, the LOD was found to 0.24 μM, 0.45 μM and 0.34 μM for DA, EP and NOR respectively. The Au-PEA-MOCAPc electrodes screened off the strong interferents, ascorbic and uric acid. The Au-PEA-FeOCAPc electrode was evaluated for its potential application in real sample analysis using new born calf serum, and it showed excellent percentage recoveries. , Thesis (MSc) -- Faculty of Science, Chemistry, 2023
- Full Text:
- Authors: Moyo, Iphithuli
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424525 , vital:72161
- Description: Octa acyl chloride metallophthalocyanines of cobalt (CoOAClPc) and iron (FeOAClPc) were synthesized and characterized using spectroscopic and electrochemical techniques. The metallophthalocyanines were fabricated as thin films onto phenylethylamine (PEA) pre-grafted Au electrode following a covalent amide reaction. The spectroscopic and electrochemical characterization confirmed the modification of the bare Au with PEA monolayer thin film (Au-PEA) and the covalent immobilization of MOAClPc to yield Au-PEA-MOAClPc (where M is Co and Fe). The acyl chloride functional groups were hydrolyzed forming pH sensitive thin films of terminal carboxylic acid (-COOH) functional groups (Au-PEA-MOCAPc). The Au-PEA-MOCAPc electrode exhibited pH selectivity and sensitivity properties towards the negatively charged [Fe(CN)6]3-/4- and positively charged [Ru(NH3)6]2+/3+ redox probes. The Au-PEA-MOCAPc electrodes were studied for their electrocatalytic and electroanalytical properties towards the detection of catecholamine neurotransmitters; dopamine (DA), epinephrine (EP) and norepinephrine (NOR). The electrodes were further investigated in the screening of ascorbic and uric acids by means of pH sensitive functional groups. The modification process exhibited good reproducibility. Excellent electrocatalytic and electroanalytical properties were observed. The limits of detection (LOD) determined using 3σ/m was found to be 64 nM, 0.22 μM and 0.17 μM for DA, EP and NOR respectively using Au-PEA-CoOCAPc. For Au-PEA-FeOCAPc, the LOD was found to 0.24 μM, 0.45 μM and 0.34 μM for DA, EP and NOR respectively. The Au-PEA-MOCAPc electrodes screened off the strong interferents, ascorbic and uric acid. The Au-PEA-FeOCAPc electrode was evaluated for its potential application in real sample analysis using new born calf serum, and it showed excellent percentage recoveries. , Thesis (MSc) -- Faculty of Science, Chemistry, 2023
- Full Text:
Investigation of microbial fuel cell technologies for flexible, small-scale domestic and educational use
- Authors: Mpofu, Trisha Lerato
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192539 , vital:45235
- Description: Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2021
- Full Text:
- Authors: Mpofu, Trisha Lerato
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/192539 , vital:45235
- Description: Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2021
- Full Text:
Identification of novel Arf1 GTPase inhibitors for cancer target validation
- Authors: Mqwathi, Nomxolisi Vuyokasi
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424666 , vital:72173
- Description: The key regulators of both anterograde and retrograde vesicular traffic, adenosine diphosphate-ribosylation factors (Arfs), also coordinate various signalling pathways and regulate cellular processes required for cell survival and function. In addition to its role in mediating secretory trafficking in the Golgi apparatus, the involvement of Arf1 in signalling pathways that contribute to the formation and progression of cancer has become apparent, and the overexpression and deregulation of Arf1 activity has been associated with cancer cell invasion, proliferation and metastasis. As with other small GTPases, Arf1 must cycle back and forth between an inactive (GDP-bound) and active (GTP-bound) conformation to carry out its function. However, the cycle of Arf1 inactivation and activation is controlled by Arf GTPase activating proteins (Arf-GAPs) that stimulate Arf1 to hydrolyse the bound GTP to GDP and Arf guanine nucleotide exchange factors (Arf-GEFs) that facilitate GDP for GTP exchange on Arf1, respectively. The identification of Arf1 inhibitors that indirectly disrupt Arf1 function by blocking its interaction with Arf-GAPs or Arf-GEFs has generated interest in their use as possible anti-cancer agents. The suppression of Arf1 activation (by targeting Arf-GEFs) has been investigated as a potential cancer therapeutic target and resulted in inhibitor compounds that have micromolar-range activity against cancer cells and targets and promising results in mouse models, but experience problems with bioavailability when used in vivo. This motivates the search for novel Arf1 inhibitors for validation purposes to question whether Arf1 is a viable target for cancer therapy. The purpose of the study was to employ a recently developed colourimetric screening assay to identify inhibitors of Arf1 activation (Arf-GEF inhibitors) and deactivation (Arf-GAP inhibitors), with a focus on evaluating the potential of Arf1 deactivation as an entirely novel anti-cancer target. The proteins required for the assay (Arf1, Arf-GEF and -GAP domains and a reporter protein, GST-GGA3) were expressed in E. coli. and purified using affinity chromatography. The assay could detect the activation of Arf1 by the catalytic Sec7 domain of the three Arf-GEFs chosen for this study, but reproducibility was compromised by the occasional spontaneous activation of Arf1 in the absence of the Arf-GEFs. By contrast, the assay could reproducibly detect Arf1 deactivation by an Arf-GAP domain (Arf-GAP1GAP) and was subsequently used to screen a library of α-helix mimetics. Thirteen hit compounds with IC50 values ranging from 0.53 to 20.95 μM were found to inhibit Arf-GAP1GAP-mediated stimulation of GTP hydrolysis by Arf1-GTP in this assay format, however, they did not effectively suppress the proliferation of three tested cell lines (HeLa, MCF-7 and MCF-12A). Interestingly, the results obtained from fluorescence microscopy studies suggested that the compounds disrupt Golgi structure and Arf1 localisation, presumably by keeping Arf1 in its active conformation by blocking Arf-GAP1 function. This suggests that the compounds affect Arf1 function in cells, and may be used to explore the feasibility of targeting Arf1 deactivation for anti-cancer purposes in a wider range of cell lines and experiments. It has been reported that Arf-GAP1 inhibition is associated with the suppression of cell migration, and the potential of the compounds as metastasis inhibitors may also be explored. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2023
- Full Text:
- Authors: Mqwathi, Nomxolisi Vuyokasi
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424666 , vital:72173
- Description: The key regulators of both anterograde and retrograde vesicular traffic, adenosine diphosphate-ribosylation factors (Arfs), also coordinate various signalling pathways and regulate cellular processes required for cell survival and function. In addition to its role in mediating secretory trafficking in the Golgi apparatus, the involvement of Arf1 in signalling pathways that contribute to the formation and progression of cancer has become apparent, and the overexpression and deregulation of Arf1 activity has been associated with cancer cell invasion, proliferation and metastasis. As with other small GTPases, Arf1 must cycle back and forth between an inactive (GDP-bound) and active (GTP-bound) conformation to carry out its function. However, the cycle of Arf1 inactivation and activation is controlled by Arf GTPase activating proteins (Arf-GAPs) that stimulate Arf1 to hydrolyse the bound GTP to GDP and Arf guanine nucleotide exchange factors (Arf-GEFs) that facilitate GDP for GTP exchange on Arf1, respectively. The identification of Arf1 inhibitors that indirectly disrupt Arf1 function by blocking its interaction with Arf-GAPs or Arf-GEFs has generated interest in their use as possible anti-cancer agents. The suppression of Arf1 activation (by targeting Arf-GEFs) has been investigated as a potential cancer therapeutic target and resulted in inhibitor compounds that have micromolar-range activity against cancer cells and targets and promising results in mouse models, but experience problems with bioavailability when used in vivo. This motivates the search for novel Arf1 inhibitors for validation purposes to question whether Arf1 is a viable target for cancer therapy. The purpose of the study was to employ a recently developed colourimetric screening assay to identify inhibitors of Arf1 activation (Arf-GEF inhibitors) and deactivation (Arf-GAP inhibitors), with a focus on evaluating the potential of Arf1 deactivation as an entirely novel anti-cancer target. The proteins required for the assay (Arf1, Arf-GEF and -GAP domains and a reporter protein, GST-GGA3) were expressed in E. coli. and purified using affinity chromatography. The assay could detect the activation of Arf1 by the catalytic Sec7 domain of the three Arf-GEFs chosen for this study, but reproducibility was compromised by the occasional spontaneous activation of Arf1 in the absence of the Arf-GEFs. By contrast, the assay could reproducibly detect Arf1 deactivation by an Arf-GAP domain (Arf-GAP1GAP) and was subsequently used to screen a library of α-helix mimetics. Thirteen hit compounds with IC50 values ranging from 0.53 to 20.95 μM were found to inhibit Arf-GAP1GAP-mediated stimulation of GTP hydrolysis by Arf1-GTP in this assay format, however, they did not effectively suppress the proliferation of three tested cell lines (HeLa, MCF-7 and MCF-12A). Interestingly, the results obtained from fluorescence microscopy studies suggested that the compounds disrupt Golgi structure and Arf1 localisation, presumably by keeping Arf1 in its active conformation by blocking Arf-GAP1 function. This suggests that the compounds affect Arf1 function in cells, and may be used to explore the feasibility of targeting Arf1 deactivation for anti-cancer purposes in a wider range of cell lines and experiments. It has been reported that Arf-GAP1 inhibition is associated with the suppression of cell migration, and the potential of the compounds as metastasis inhibitors may also be explored. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2023
- Full Text:
Implementing a sexual and reproductive citizenship intervention refinement instrument for youth sexuality education: a formative evaluation
- Authors: Mthethwa, Thobile
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/425008 , vital:72201
- Description: While Out of School sexuality education (SE) programmes in South Africa have attempted to bridge the gap in the number of young people who receive SE, there is still a large number of youth between the age groups of 15 to 24 years who lack adequate sexual knowledge. The manner in which sex education is taught and its accessibility is accompanied by challenges, in particular in relation to empowerment. To better understand the effectiveness of sexual education programmes, evaluations of their content is needed. Therefore, the purpose of this study was to investigate whether and how an Out of school SE programme run by Partners in Sexual Health (PSH) promotes understandings of sexual and reproductive citizenship. A formative evaluation of their sexual and reproductive health and rights (SRHR) facilitator’s manual was conducted (owing to COVID the actual programme was not run in the year data for this thesis were collected). To help perform the formative evaluation, the feminist sexual and reproductive citizenship (SRC) framework as conceptualized by Macleod and Vincent (2014) was used. The SRC framework consists of five key principles that, it is suggested, need to be adopted for SE programmes to be inclusive, namely, citizenship as status and practice, differentiated citizenship, private and public interstice, and politics of recognition, redistribution and reparation. An additional principle of inclusive and process-based educational practices was added into the five key principles. To analyse data, template analysis was used which enabled the researcher to create a priori of themes using the Masizixhobise toolkit which is informed by the SRC framework. Findings from this study reveal the interconnectedness between the different citizenship principles. Moreover, while the PSH SRHR programme promotes principles of the SRC framework, there are aspects of the SRC that are lacking from the programme. Therefore, the SRHR manual needs to take into account a spectrum of issues which include but are not limited to the incorporation of sexually diverse differently-abled individuals' sexual experiences and challenges when it comes to accessing SE. This means for SE programmes to achieve inclusivity and to be empowering, they need to encourage individuals to be agentic beings, engage in informed decision-making and encourage young people to take up their rights. , Thesis (MA) -- Faculty of Humanities, Psychology, 2023
- Full Text:
- Authors: Mthethwa, Thobile
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/425008 , vital:72201
- Description: While Out of School sexuality education (SE) programmes in South Africa have attempted to bridge the gap in the number of young people who receive SE, there is still a large number of youth between the age groups of 15 to 24 years who lack adequate sexual knowledge. The manner in which sex education is taught and its accessibility is accompanied by challenges, in particular in relation to empowerment. To better understand the effectiveness of sexual education programmes, evaluations of their content is needed. Therefore, the purpose of this study was to investigate whether and how an Out of school SE programme run by Partners in Sexual Health (PSH) promotes understandings of sexual and reproductive citizenship. A formative evaluation of their sexual and reproductive health and rights (SRHR) facilitator’s manual was conducted (owing to COVID the actual programme was not run in the year data for this thesis were collected). To help perform the formative evaluation, the feminist sexual and reproductive citizenship (SRC) framework as conceptualized by Macleod and Vincent (2014) was used. The SRC framework consists of five key principles that, it is suggested, need to be adopted for SE programmes to be inclusive, namely, citizenship as status and practice, differentiated citizenship, private and public interstice, and politics of recognition, redistribution and reparation. An additional principle of inclusive and process-based educational practices was added into the five key principles. To analyse data, template analysis was used which enabled the researcher to create a priori of themes using the Masizixhobise toolkit which is informed by the SRC framework. Findings from this study reveal the interconnectedness between the different citizenship principles. Moreover, while the PSH SRHR programme promotes principles of the SRC framework, there are aspects of the SRC that are lacking from the programme. Therefore, the SRHR manual needs to take into account a spectrum of issues which include but are not limited to the incorporation of sexually diverse differently-abled individuals' sexual experiences and challenges when it comes to accessing SE. This means for SE programmes to achieve inclusivity and to be empowering, they need to encourage individuals to be agentic beings, engage in informed decision-making and encourage young people to take up their rights. , Thesis (MA) -- Faculty of Humanities, Psychology, 2023
- Full Text:
Distribution and conservation status assessment of the freshwater fishes in the Krom River system in the Eastern Cape Province, South Africa
- Authors: Mthombeni, Annah
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422303 , vital:71929
- Description: The Cape Fold Ecoregion (CFE) contains the highest number of endemic freshwater fishes in Africa, south of the Zambezi River system. The CFE’s unique fish fauna has, however, suffered severe decline in historical distribution ranges and population sizes due to multiple impacts, with the two main threats being introduced invasive piscivores and habitat degradation. Growing evidence shows that biodiversity is being lost at unprecedented levels due to increased human pressure and demand for limited resources. Future projections also indicate high extinction risk, particularly for freshwater ecosystems, as a result of global climate change. Yet for many regions, including the CFE, there is still limited biodiversity knowledge to guide decision making processes. The Krom River system in the eastern Cape Fold Ecoregion (CFE) contains three native freshwater fish species. These are Pseudobarbus senticeps, which was recently revalidated, Sandelia capensis and a galaxiid lineage currently informally referred to as Galaxias zebratus sp. ‘Joubertina’. Two of these taxa are listed under threatened categories of the International Union for Conservation of Nature (IUCN). These are P. senticeps, which is listed as Critically Endangered and Galaxias zebratus sp. ‘Joubertina’, which is listed as Endangered. Although S. capensis is currently listed as Data Deficient, the most recent information indicates that the species comprises three allopatric lineages, with the Krom River population belonging to a lineage that is distributed across a number of river systems on the south coast. Two non-native fishes, Micropterus salmoides and Lepomis macrochirus, have also been introduced into this river system. Updated information on distribution patterns and habitat utilisation is required to guide authorities to develop effective management plans and conservation of the threatened fishes of the Krom River system. The aim of this study was to determine the current distribution of the fishes of the Krom River system and to provide recommendations for in situ conservation measures to protect remnant populations and promote recovery and range expansion of the native fishes. The primary objective of the study was to use historical and present data to map the distributions patterns. Data on the distribution of the fishes of the Krom River system were obtained from various sources, including the NRF-SAIAB database, studies published in peer reviewed literature and unpublished reports. Systematic sampling was conducted in the Krom River system and several of its tributaries to provide a snapshot of the current distribution of both native and non-native fishes in this system at the time of this study. The presence of instream physical barriers was recorded, and habitat and water quality were visually assessed. Only four species of freshwater fishes were recorded during the surveys. These were two native species, the Krom River redfin P. senticeps and the Cape kurper Sandelia capensis, and two introduced species, the black bass M. salmoides and bluegill sunfish L. macrochirus. Pseudobarbus senticeps was the most common and widely distributed species in the system, and was recorded at 20 localities (four mainstem and 16 tributary localities). Sandelia capensis was less common and was recorded at only eight localities (four mainstem and four tributary localities). These two native species co-occurred at all the eight localities where S. capensis was recorded, but P. senticeps was always more abundant than Sandelia. Micropterus salmoides was recorded at six localities (four mainstem and 2 tributary localities) while L. macrochirus was recorded at five localities (four mainstem and one off-stream dam site). Native fishes were not recorded at sites where non-native fishes were present except at two localities in the Wit Els River where juvenile M. salmoides were found amongst the native fish samples. However, unlike the other localities where all size classes (i.e., young of the year, juveniles, subadults and adults) were present, only adult redfins were found in the Wit Els River where juveniles of largemouth bass occurred. A comparison of the past and present distribution patterns of the native fishes indicates a considerable decline in distribution range, and remnant populations are now fragmented compared to past observations. The major threats and impacts on the Krom River system are the presence of non-native piscivores, construction of instream physical barriers, and agricultural activities. The information from this study could form a basis for establishing long-term conservation measures that should focus on preventing the spread of non-native fishes, and rehabilitating critical habitats for the future persistence of remnant populations of native fishes. The study also evaluated the implications of incomplete taxonomy on conservation status assessments and prioritisation, by evaluating case studies of species complexes of freshwater fishes whose taxonomy has been recently resolved, as well as two complexes with lineages that await formal recognition as distinct species. The aim was to demonstrate how incomplete knowledge of taxonomy affects the assessment of extinction risk and can potentially misdirect conservation prioritisation. Specifically, the study examined how change in taxonomy or recognition of undescribed genetic lineages in faunal listings affects range size and IUCN Red List risk category. The study taxa were Pseudobarbus afer sensu lato (sl), Enteromius anoplus sl, Amphilius natalensis sl, Sandelia capensis and S. bainsii, and the study assessed the species complexes as Least Concern or Near Threatened. The majority of these taxonomically revised species and genetic lineages were determined to be Critically Endangered (CR), Endangered (EN) and Vulnerable (VU), as the extent of occurrence was estimated to be < 100 km2; < 5000 km2 and < 20 000 km2 respectively. The species and lineages have been observed in fewer than ten locations, and the populations have been observed to be in decline. The results of this study indicate that the current taxonomic status of the native species in the Krom River system obscures the diversity of these fishes and affects conclusions for conservation assessments. Findings from this preliminary assessment highlight the need for advancing taxonomic knowledge through accurate delimitation of species boundaries, particularly within , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
- Authors: Mthombeni, Annah
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422303 , vital:71929
- Description: The Cape Fold Ecoregion (CFE) contains the highest number of endemic freshwater fishes in Africa, south of the Zambezi River system. The CFE’s unique fish fauna has, however, suffered severe decline in historical distribution ranges and population sizes due to multiple impacts, with the two main threats being introduced invasive piscivores and habitat degradation. Growing evidence shows that biodiversity is being lost at unprecedented levels due to increased human pressure and demand for limited resources. Future projections also indicate high extinction risk, particularly for freshwater ecosystems, as a result of global climate change. Yet for many regions, including the CFE, there is still limited biodiversity knowledge to guide decision making processes. The Krom River system in the eastern Cape Fold Ecoregion (CFE) contains three native freshwater fish species. These are Pseudobarbus senticeps, which was recently revalidated, Sandelia capensis and a galaxiid lineage currently informally referred to as Galaxias zebratus sp. ‘Joubertina’. Two of these taxa are listed under threatened categories of the International Union for Conservation of Nature (IUCN). These are P. senticeps, which is listed as Critically Endangered and Galaxias zebratus sp. ‘Joubertina’, which is listed as Endangered. Although S. capensis is currently listed as Data Deficient, the most recent information indicates that the species comprises three allopatric lineages, with the Krom River population belonging to a lineage that is distributed across a number of river systems on the south coast. Two non-native fishes, Micropterus salmoides and Lepomis macrochirus, have also been introduced into this river system. Updated information on distribution patterns and habitat utilisation is required to guide authorities to develop effective management plans and conservation of the threatened fishes of the Krom River system. The aim of this study was to determine the current distribution of the fishes of the Krom River system and to provide recommendations for in situ conservation measures to protect remnant populations and promote recovery and range expansion of the native fishes. The primary objective of the study was to use historical and present data to map the distributions patterns. Data on the distribution of the fishes of the Krom River system were obtained from various sources, including the NRF-SAIAB database, studies published in peer reviewed literature and unpublished reports. Systematic sampling was conducted in the Krom River system and several of its tributaries to provide a snapshot of the current distribution of both native and non-native fishes in this system at the time of this study. The presence of instream physical barriers was recorded, and habitat and water quality were visually assessed. Only four species of freshwater fishes were recorded during the surveys. These were two native species, the Krom River redfin P. senticeps and the Cape kurper Sandelia capensis, and two introduced species, the black bass M. salmoides and bluegill sunfish L. macrochirus. Pseudobarbus senticeps was the most common and widely distributed species in the system, and was recorded at 20 localities (four mainstem and 16 tributary localities). Sandelia capensis was less common and was recorded at only eight localities (four mainstem and four tributary localities). These two native species co-occurred at all the eight localities where S. capensis was recorded, but P. senticeps was always more abundant than Sandelia. Micropterus salmoides was recorded at six localities (four mainstem and 2 tributary localities) while L. macrochirus was recorded at five localities (four mainstem and one off-stream dam site). Native fishes were not recorded at sites where non-native fishes were present except at two localities in the Wit Els River where juvenile M. salmoides were found amongst the native fish samples. However, unlike the other localities where all size classes (i.e., young of the year, juveniles, subadults and adults) were present, only adult redfins were found in the Wit Els River where juveniles of largemouth bass occurred. A comparison of the past and present distribution patterns of the native fishes indicates a considerable decline in distribution range, and remnant populations are now fragmented compared to past observations. The major threats and impacts on the Krom River system are the presence of non-native piscivores, construction of instream physical barriers, and agricultural activities. The information from this study could form a basis for establishing long-term conservation measures that should focus on preventing the spread of non-native fishes, and rehabilitating critical habitats for the future persistence of remnant populations of native fishes. The study also evaluated the implications of incomplete taxonomy on conservation status assessments and prioritisation, by evaluating case studies of species complexes of freshwater fishes whose taxonomy has been recently resolved, as well as two complexes with lineages that await formal recognition as distinct species. The aim was to demonstrate how incomplete knowledge of taxonomy affects the assessment of extinction risk and can potentially misdirect conservation prioritisation. Specifically, the study examined how change in taxonomy or recognition of undescribed genetic lineages in faunal listings affects range size and IUCN Red List risk category. The study taxa were Pseudobarbus afer sensu lato (sl), Enteromius anoplus sl, Amphilius natalensis sl, Sandelia capensis and S. bainsii, and the study assessed the species complexes as Least Concern or Near Threatened. The majority of these taxonomically revised species and genetic lineages were determined to be Critically Endangered (CR), Endangered (EN) and Vulnerable (VU), as the extent of occurrence was estimated to be < 100 km2; < 5000 km2 and < 20 000 km2 respectively. The species and lineages have been observed in fewer than ten locations, and the populations have been observed to be in decline. The results of this study indicate that the current taxonomic status of the native species in the Krom River system obscures the diversity of these fishes and affects conclusions for conservation assessments. Findings from this preliminary assessment highlight the need for advancing taxonomic knowledge through accurate delimitation of species boundaries, particularly within , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
Evaluating the potential effects of microplastics at environmentally realistic concentrations in South African freshwater systems
- Authors: Mtintsilana, Zintle
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424160 , vital:72129
- Description: Microplastic pollution is spatially broad, microplastics can be found in various habitats including freshwater systems. Microplastic exposure to aquatic organisms has been associated with several physical impacts on aquatic organisms from multiple trophic levels such as; increased immune response, a decrease in food intake, excessive loss of weight, reduced growth rate, reduced energy and adverse effects on successive generations. However, these significant effects of microplastics exposure have been observed mostly in studies that use concentrations of microplastics that exceed environmental concentrations. Therefore, there is an overall lack of research on the effects of microplastics on freshwater organisms using environmentally realistic concentrations, especially in the Southern Hemisphere. A series of toxicity tests were used to expose a range of taxa including Tilapia sparrmanii, Caridina nilotica, and Melanoides tuberculata to different environmentally realistic concentrations of microplastics of different polymers. The study results show that the environmentally realistic concentrations had no statistically significant effects on most of the chosen test organisms and selected study endpoints, except for T. sparrmanii microplastic particle egestion and growth in polyethylene exposures which produced significant results. Although this study showed that at environmentally realistic concentrations and 21 days of exposure, minute effects on the test taxa were detected, various studies have proven that with longer exposure to microplastics, significant effects on freshwater organisms can be detected. Additionally, studies using concentrations higher than the current environmental concentrations have recorded significant effects on organisms and therefore, with increasing concentrations in the environment, more significant effects may be observed. Therefore, plastic pollution in the environment should be reduced as microplastics are in continuous production and circulation, and microplastic concentrations in freshwater environments are predicted to increase. , Thesis (MSc) -- Faculty of Science, Institute for Water Research, 2023
- Full Text:
- Authors: Mtintsilana, Zintle
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424160 , vital:72129
- Description: Microplastic pollution is spatially broad, microplastics can be found in various habitats including freshwater systems. Microplastic exposure to aquatic organisms has been associated with several physical impacts on aquatic organisms from multiple trophic levels such as; increased immune response, a decrease in food intake, excessive loss of weight, reduced growth rate, reduced energy and adverse effects on successive generations. However, these significant effects of microplastics exposure have been observed mostly in studies that use concentrations of microplastics that exceed environmental concentrations. Therefore, there is an overall lack of research on the effects of microplastics on freshwater organisms using environmentally realistic concentrations, especially in the Southern Hemisphere. A series of toxicity tests were used to expose a range of taxa including Tilapia sparrmanii, Caridina nilotica, and Melanoides tuberculata to different environmentally realistic concentrations of microplastics of different polymers. The study results show that the environmentally realistic concentrations had no statistically significant effects on most of the chosen test organisms and selected study endpoints, except for T. sparrmanii microplastic particle egestion and growth in polyethylene exposures which produced significant results. Although this study showed that at environmentally realistic concentrations and 21 days of exposure, minute effects on the test taxa were detected, various studies have proven that with longer exposure to microplastics, significant effects on freshwater organisms can be detected. Additionally, studies using concentrations higher than the current environmental concentrations have recorded significant effects on organisms and therefore, with increasing concentrations in the environment, more significant effects may be observed. Therefore, plastic pollution in the environment should be reduced as microplastics are in continuous production and circulation, and microplastic concentrations in freshwater environments are predicted to increase. , Thesis (MSc) -- Faculty of Science, Institute for Water Research, 2023
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Factors influencing the number of non-timber forest product species used at the individual, household and village levels in Vhembe, Limpopo Province, South Africa
- Authors: Mulaudzi, Takalani Rachel
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422481 , vital:71946
- Description: Non-Timber Forest Products (NTFPs) are wild biological resources obtained from natural landscapes, agricultural systems, and rural and urban regions for a variety of uses. NTFPs contribute significantly to livelihoods and living standards by offering a variety of socioeconomic benefits such as food, health, income generation, and safety nets. These multiple benefits are provided by a wide diversity of plant, animal and fungal species in different settings. However, the precise number of NTFP species used depends on the scale of assessment, namely use by individuals, by households and by villages. Consequently, it is difficult to compare numbers of species used between studies because of the differing scales. As a result, the objective of this study was to determine the number of NTFP species used at three different scales and how each is correlated with appropriate scale-dependent contextual variables. This objective was met by sampling individuals and whole households in five villages in the Vhembe District in Limpopo Province, South Africa. Twenty households were randomly selected in each village, providing a total sample of 100 households and 179 individuals in those households. In each household, every adult member was interviewed individually about the NTFPs that they used or knew. The major questions covered the NTFP species used, the respondents' socioeconomic level, the NTFP species used previously, and if the number of NTFP species are changing in the landscape. Data were reported per individual as well as per household and per village. The household level was derived by adding the responses of all the adults in each household but excluding duplicates. The same approach was used at the village scale, namely, the data across the 20 households were pooled, and duplicates were omitted. Patterns of NTFP use were examined by type of NTFP, and analysis using standard statistical tests, along with a Principal Components Analysis and a multivariate Detrended Correspondence Analysis of the NTFP species composition across villages. A total of 275 species of NTFPs were mentioned across the entire sample, including 81 species of firewood, 48 species of edible insects, 43 species of wild vegetables, 40 species of edible fruits, 38 species of wood utensils, 28 species of medicinal plants, 23 species of thatch grass, 19 species of poles, 19 species of wood for carvings, nine species of reeds, eight species of mushroom, and eight species of fodder. Of these species, some species had more than one use. Approximately 90% of the species used by the respondents were native species. Wild vegetables (e.g., Corchorus olitorius, Amaranthus capensis, Bidens pilosa), firewood (e.g., Colophospermum mopane, Parinari curatellifolia, Combretum hereroense), wild fruit (e.g., Landolphia kirkii, Vangueria infausta), and edible insects (e.g., Imbrasia belina, Macrotermes michaelseni, Encosternum delegorguei) were the most often used NTFPs by communities in the Vhembe area. Most of the households relied on NTFPs for subsistence. At the scale of an individual, the mean number of NTFP species used was 26.8±12.6 across the five villages. When considering a household, the mean number was 36.1±10.7 species. When aggregated across the 20 households per village, the mean number per village was 105.2±34.1 species. The species accumulation curve showed that 20 households per village were reasonably representative for four of the five villages. The results from the principal component analysis (PCA) and correlation analysis revealed that age, education, and employment status were significantly associated with the number of species used by individuals, whereas gender showed no clear correlation. At the household scale, household size was positively related with the number of species used, but income level and income source were not. At the village scale, attributes such as proximity to a town, settlement type, vegetation type, and distance to a nearby savanna all had some influence on the number of NTFP species listed. Most of the respondents felt that the number of species used had increased over the last 10–15 years, although some stated the opposite. Increases were attributed by traditional councils bans, the establishment of protected areas, and restoration. Activities eroding the number of NTFP species were identified as clear felling for farming, climate change, and over-harvesting. This study suggests that communities must be made more aware of the overharvesting of NTFP species in the savanna to avoid biodiversity loss. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2023
- Full Text:
- Authors: Mulaudzi, Takalani Rachel
- Date: 2023-03-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/422481 , vital:71946
- Description: Non-Timber Forest Products (NTFPs) are wild biological resources obtained from natural landscapes, agricultural systems, and rural and urban regions for a variety of uses. NTFPs contribute significantly to livelihoods and living standards by offering a variety of socioeconomic benefits such as food, health, income generation, and safety nets. These multiple benefits are provided by a wide diversity of plant, animal and fungal species in different settings. However, the precise number of NTFP species used depends on the scale of assessment, namely use by individuals, by households and by villages. Consequently, it is difficult to compare numbers of species used between studies because of the differing scales. As a result, the objective of this study was to determine the number of NTFP species used at three different scales and how each is correlated with appropriate scale-dependent contextual variables. This objective was met by sampling individuals and whole households in five villages in the Vhembe District in Limpopo Province, South Africa. Twenty households were randomly selected in each village, providing a total sample of 100 households and 179 individuals in those households. In each household, every adult member was interviewed individually about the NTFPs that they used or knew. The major questions covered the NTFP species used, the respondents' socioeconomic level, the NTFP species used previously, and if the number of NTFP species are changing in the landscape. Data were reported per individual as well as per household and per village. The household level was derived by adding the responses of all the adults in each household but excluding duplicates. The same approach was used at the village scale, namely, the data across the 20 households were pooled, and duplicates were omitted. Patterns of NTFP use were examined by type of NTFP, and analysis using standard statistical tests, along with a Principal Components Analysis and a multivariate Detrended Correspondence Analysis of the NTFP species composition across villages. A total of 275 species of NTFPs were mentioned across the entire sample, including 81 species of firewood, 48 species of edible insects, 43 species of wild vegetables, 40 species of edible fruits, 38 species of wood utensils, 28 species of medicinal plants, 23 species of thatch grass, 19 species of poles, 19 species of wood for carvings, nine species of reeds, eight species of mushroom, and eight species of fodder. Of these species, some species had more than one use. Approximately 90% of the species used by the respondents were native species. Wild vegetables (e.g., Corchorus olitorius, Amaranthus capensis, Bidens pilosa), firewood (e.g., Colophospermum mopane, Parinari curatellifolia, Combretum hereroense), wild fruit (e.g., Landolphia kirkii, Vangueria infausta), and edible insects (e.g., Imbrasia belina, Macrotermes michaelseni, Encosternum delegorguei) were the most often used NTFPs by communities in the Vhembe area. Most of the households relied on NTFPs for subsistence. At the scale of an individual, the mean number of NTFP species used was 26.8±12.6 across the five villages. When considering a household, the mean number was 36.1±10.7 species. When aggregated across the 20 households per village, the mean number per village was 105.2±34.1 species. The species accumulation curve showed that 20 households per village were reasonably representative for four of the five villages. The results from the principal component analysis (PCA) and correlation analysis revealed that age, education, and employment status were significantly associated with the number of species used by individuals, whereas gender showed no clear correlation. At the household scale, household size was positively related with the number of species used, but income level and income source were not. At the village scale, attributes such as proximity to a town, settlement type, vegetation type, and distance to a nearby savanna all had some influence on the number of NTFP species listed. Most of the respondents felt that the number of species used had increased over the last 10–15 years, although some stated the opposite. Increases were attributed by traditional councils bans, the establishment of protected areas, and restoration. Activities eroding the number of NTFP species were identified as clear felling for farming, climate change, and over-harvesting. This study suggests that communities must be made more aware of the overharvesting of NTFP species in the savanna to avoid biodiversity loss. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2023
- Full Text:
Technological pedagogical content knowledge development: investigating secondary school teachers' integration and use of technology during emergency remote teaching in Endola education circuit
- Authors: Munyanyo, Johanna
- Date: 2023-10
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/423882 , vital:72101
- Description: The Covid-19 pandemic has created the largest disruption of education systems in human history. The closure of schools and other learning spaces has impacted billions of learners worldwide. The mitigative measures and many new standard operating procedures have brought restrictions and many challenges. The face-to-face traditional teaching method lost its value, and teaching shifted to distance through the integration of technologies. The integration of technologies necessitated the emergency remote teaching process, as it is one of the distance teaching modes that can make teaching possible even for less technologically privileged nations. Literature has shown that the integration and usage of technology during teaching support the development of technological pedagogical and content knowledge (TPACK) of teachers. This study, therefore, sought to investigate how the integration and use of technology during the emergency remote teaching of Covid-19 developed the secondary school teachers’ technological pedagogical and content knowledge. The study is underpinned by an interpretive paradigm, and a qualitative case study approach was employed. It was conducted in seven secondary schools in the Endola education circuit, Ohangwena region, with the purposeful participation of twenty-six secondary school teachers. Data was collected using semi-structured questionnaires and semi-structured interviews. The study was informed by Vygotsky’s (1978) sociocultural theory together with the TPACK framework of Thompson and Mishra (2007) as both theoretical and analytical frameworks. The study's results showed that teachers made use of existing technological resources to sustain their teaching efforts during ERT. They encountered various challenges, including a lack of technological expertise (knowledge) among both teachers and learners. The shift to virtual instruction during ERT supported teachers in developing proficient technological pedagogical content knowledge. This research concludes that schools possess the necessary technological infrastructure to enable teachers to incorporate technology into their teaching methods. Furthermore, it highlights that teachers generally hold favourable attitudes toward integrating technology into their instruction. Nevertheless, it recommends that there is a need for improving both in-service and pre-service teachers’ training and support for effectively teaching in online and blended learning environments. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2023
- Full Text:
- Authors: Munyanyo, Johanna
- Date: 2023-10
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/423882 , vital:72101
- Description: The Covid-19 pandemic has created the largest disruption of education systems in human history. The closure of schools and other learning spaces has impacted billions of learners worldwide. The mitigative measures and many new standard operating procedures have brought restrictions and many challenges. The face-to-face traditional teaching method lost its value, and teaching shifted to distance through the integration of technologies. The integration of technologies necessitated the emergency remote teaching process, as it is one of the distance teaching modes that can make teaching possible even for less technologically privileged nations. Literature has shown that the integration and usage of technology during teaching support the development of technological pedagogical and content knowledge (TPACK) of teachers. This study, therefore, sought to investigate how the integration and use of technology during the emergency remote teaching of Covid-19 developed the secondary school teachers’ technological pedagogical and content knowledge. The study is underpinned by an interpretive paradigm, and a qualitative case study approach was employed. It was conducted in seven secondary schools in the Endola education circuit, Ohangwena region, with the purposeful participation of twenty-six secondary school teachers. Data was collected using semi-structured questionnaires and semi-structured interviews. The study was informed by Vygotsky’s (1978) sociocultural theory together with the TPACK framework of Thompson and Mishra (2007) as both theoretical and analytical frameworks. The study's results showed that teachers made use of existing technological resources to sustain their teaching efforts during ERT. They encountered various challenges, including a lack of technological expertise (knowledge) among both teachers and learners. The shift to virtual instruction during ERT supported teachers in developing proficient technological pedagogical content knowledge. This research concludes that schools possess the necessary technological infrastructure to enable teachers to incorporate technology into their teaching methods. Furthermore, it highlights that teachers generally hold favourable attitudes toward integrating technology into their instruction. Nevertheless, it recommends that there is a need for improving both in-service and pre-service teachers’ training and support for effectively teaching in online and blended learning environments. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2023
- Full Text:
Evaluating the potential of monometallic and bimetallic nanomaterials as horseradish peroxidase mimetics
- Authors: Mvango, Sindisiwe
- Date: 2017
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/65134 , vital:28694
- Description: This study presents the synthesis of citrate-capped gold nanoparticles (cit-AuNPs), copper oxide nanoparticles (CuONPs), glutathione-capped gold nanoparticles (GSH-AuNPs), 4- aminothiophenol-capped gold nanoparticles (4-ATP-AuNPs), 4-mercapto benzoic acid- capped gold nanoparticles (4-MBA-AuNPs) and copper oxide gold nanoalloys (CuO-Au nanoalloys). Microscopy and spectroscopy techniques were used to confirm the successful synthesis of these nanoparticles. The synthesized nanoparticles were studied their potential applications as horseradish peroxidase (HPR) enzyme mimetics and for the detection of glucose. The cit-AuNPs and GSH-AuNPs exhibited peroxidase-like activity towards hydrogen peroxide (H2O2) with high Michaelis-Menten (Km) values of 61.5 mM and 30.8 mM, respectively. The other nanoparticles, that is, 4-ATP-AuNPs, CuONPs and CuO-Au nanoalloys gave lower Km values of 4.74 mM, 1.92 mM and 4.05 mM, respectively. The obtained Km values were comparable to those of HRP enzymes which ranged from 0.214 - 3.70 mM with 4-ATP-AuNPs and CuO-Au nanoalloys slightly higher. These values were within the reasonable experimental values of the HRP enzyme. The studies showed that the gold nanoparticles had low adsorptive efficiency towards H2O2 compared to the copper-based nanoparticles (CuONPs and CuO-Au nanoalloys). The CuO-Au nanoalloys also showed the synergistic effect between the gold and copper nanoparticles with extended linear concentration range for the quantification of H2O2. The mechanism of catalysis was confirmed using UV-vis spectroscopy and electron paramagnetic resonance (EPR) in that the generation of reactive oxygen species was observed. The use of 1,3-diphenylisobenzofuran (DPBF) as radical quencher and 5,5- dimethyl-1-pyrroline N-oxide (DMPO) as a radical scavenger confirmed the production of reductive reactive oxygen species using UV-vis and EPR studies. The rate of production of reactive oxygen species in the gold-based nanoparticles was small compared to the copper-based nanoparticles, that is CuONPs and CuO-Au (bimetallic) nanoalloys. The synthesized nanoparticles were further studied their potential use in the colorimetric detection of glucose. The copper-based nanomaterials, CuONPs and CuO-Au nanoalloys, were excellent towards detection of glucose, with a limit of detection (LoD) of 9.34 pM for CuONPs and 6.75 pM for CuO-Au nanoalloys. The linear concentration (LCR) range of CuONPs was 0 to 70 pM and for CuO-Au nanoalloys the LCR was 0.0 - 30 pM. , Thesis (MSc) -- Faculty of Science, Chemistry, 2017
- Full Text:
- Authors: Mvango, Sindisiwe
- Date: 2017
- Subjects: Uncatalogued
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10962/65134 , vital:28694
- Description: This study presents the synthesis of citrate-capped gold nanoparticles (cit-AuNPs), copper oxide nanoparticles (CuONPs), glutathione-capped gold nanoparticles (GSH-AuNPs), 4- aminothiophenol-capped gold nanoparticles (4-ATP-AuNPs), 4-mercapto benzoic acid- capped gold nanoparticles (4-MBA-AuNPs) and copper oxide gold nanoalloys (CuO-Au nanoalloys). Microscopy and spectroscopy techniques were used to confirm the successful synthesis of these nanoparticles. The synthesized nanoparticles were studied their potential applications as horseradish peroxidase (HPR) enzyme mimetics and for the detection of glucose. The cit-AuNPs and GSH-AuNPs exhibited peroxidase-like activity towards hydrogen peroxide (H2O2) with high Michaelis-Menten (Km) values of 61.5 mM and 30.8 mM, respectively. The other nanoparticles, that is, 4-ATP-AuNPs, CuONPs and CuO-Au nanoalloys gave lower Km values of 4.74 mM, 1.92 mM and 4.05 mM, respectively. The obtained Km values were comparable to those of HRP enzymes which ranged from 0.214 - 3.70 mM with 4-ATP-AuNPs and CuO-Au nanoalloys slightly higher. These values were within the reasonable experimental values of the HRP enzyme. The studies showed that the gold nanoparticles had low adsorptive efficiency towards H2O2 compared to the copper-based nanoparticles (CuONPs and CuO-Au nanoalloys). The CuO-Au nanoalloys also showed the synergistic effect between the gold and copper nanoparticles with extended linear concentration range for the quantification of H2O2. The mechanism of catalysis was confirmed using UV-vis spectroscopy and electron paramagnetic resonance (EPR) in that the generation of reactive oxygen species was observed. The use of 1,3-diphenylisobenzofuran (DPBF) as radical quencher and 5,5- dimethyl-1-pyrroline N-oxide (DMPO) as a radical scavenger confirmed the production of reductive reactive oxygen species using UV-vis and EPR studies. The rate of production of reactive oxygen species in the gold-based nanoparticles was small compared to the copper-based nanoparticles, that is CuONPs and CuO-Au (bimetallic) nanoalloys. The synthesized nanoparticles were further studied their potential use in the colorimetric detection of glucose. The copper-based nanomaterials, CuONPs and CuO-Au nanoalloys, were excellent towards detection of glucose, with a limit of detection (LoD) of 9.34 pM for CuONPs and 6.75 pM for CuO-Au nanoalloys. The linear concentration (LCR) range of CuONPs was 0 to 70 pM and for CuO-Au nanoalloys the LCR was 0.0 - 30 pM. , Thesis (MSc) -- Faculty of Science, Chemistry, 2017
- Full Text: