Design, synthesis and evaluation of silver-specific ligands
- Authors: Daubinet, André
- Date: 2001
- Subjects: Ligands Ligands -- Design Ligands -- Analysis Ligands -- Evaluation Silver -- Metallurgy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4308 , http://hdl.handle.net/10962/d1004966
- Description: Several series of ligands, designed to chelate silver(I) specifically in the presence of base metals, have been synthesised. The ligands include: - dithiodiamide compounds, prepared by the condensation of acetanilide derivatives with 1,2-dibromoethane; propanenitrile and propanoic ester derivatives prepared from pyridine-2-carbaldehyde via the Morita-Baylis-Hillman reaction; and novel malonamide ligands from the reaction of diethyl malonate with a range of primary amines. The malonamide derivatives were prepared under both conventional thermal and microwave-assisted conditions, the latter proving to be highly efficient. The ligands were all characterised using a combination of spectroscopic and, where appropriate, elemental analysis; in one case, the structural assignment was confirmed by single-crystal X-ray analysis. The fragmentation patterns in the electron-impact mass spectra of the malonamide derivatives have been explored using high-resolution and meta-stable peak scanning techniques. Complexes of the malonamide ligands with copper(II) and silver(I) have been synthesised, and examination of these complexes has revealed distinct differences in their co-ordination preferences towards silver(I) and copper(II). Tentative, computer-modelled structures for the complexes have been proposed using the available spectroscopic and elemental analysis data. Computer modelling, at the Molecular Mechanics level, has also been used to assess the capacity of the ligand systems to adopt conformations suitable for the chelation of tetrahedral silver(I). Solvent extraction studies have been undertaken using aqueous metal ion solutions and various organic solvents. The dithiodiamide derivatives typically presented solubility problems, but one of the ligands, N,N´-bis(3-chlorophenyl)-3,6-dithiaoctanediamide, exhibited significant but slow extraction of silver(I) into toluene. The malonamide derivatives, however, proved to be readily soluble in ethyl acetate and, in some cases, exhibited good to excellent selectivity for silver(I) in the presence of the base metals copper and lead. Atomic absorption analysis revealed rapid equilibration times (<15 min) and high extraction efficiencies over a wide pH range (2.78 - 9.0). Metal selectivity has been determined by ICP-MS analysis of the residual silver, copper and lead present in the aqueous phase after 15 min, and one of the ligands, N,N´-bis(2-benzylsulfanylethyl)malonamide, exhibits excellent (≥ 96 %) silver(I) specificity.
- Full Text:
- Date Issued: 2001
- Authors: Daubinet, André
- Date: 2001
- Subjects: Ligands Ligands -- Design Ligands -- Analysis Ligands -- Evaluation Silver -- Metallurgy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4308 , http://hdl.handle.net/10962/d1004966
- Description: Several series of ligands, designed to chelate silver(I) specifically in the presence of base metals, have been synthesised. The ligands include: - dithiodiamide compounds, prepared by the condensation of acetanilide derivatives with 1,2-dibromoethane; propanenitrile and propanoic ester derivatives prepared from pyridine-2-carbaldehyde via the Morita-Baylis-Hillman reaction; and novel malonamide ligands from the reaction of diethyl malonate with a range of primary amines. The malonamide derivatives were prepared under both conventional thermal and microwave-assisted conditions, the latter proving to be highly efficient. The ligands were all characterised using a combination of spectroscopic and, where appropriate, elemental analysis; in one case, the structural assignment was confirmed by single-crystal X-ray analysis. The fragmentation patterns in the electron-impact mass spectra of the malonamide derivatives have been explored using high-resolution and meta-stable peak scanning techniques. Complexes of the malonamide ligands with copper(II) and silver(I) have been synthesised, and examination of these complexes has revealed distinct differences in their co-ordination preferences towards silver(I) and copper(II). Tentative, computer-modelled structures for the complexes have been proposed using the available spectroscopic and elemental analysis data. Computer modelling, at the Molecular Mechanics level, has also been used to assess the capacity of the ligand systems to adopt conformations suitable for the chelation of tetrahedral silver(I). Solvent extraction studies have been undertaken using aqueous metal ion solutions and various organic solvents. The dithiodiamide derivatives typically presented solubility problems, but one of the ligands, N,N´-bis(3-chlorophenyl)-3,6-dithiaoctanediamide, exhibited significant but slow extraction of silver(I) into toluene. The malonamide derivatives, however, proved to be readily soluble in ethyl acetate and, in some cases, exhibited good to excellent selectivity for silver(I) in the presence of the base metals copper and lead. Atomic absorption analysis revealed rapid equilibration times (<15 min) and high extraction efficiencies over a wide pH range (2.78 - 9.0). Metal selectivity has been determined by ICP-MS analysis of the residual silver, copper and lead present in the aqueous phase after 15 min, and one of the ligands, N,N´-bis(2-benzylsulfanylethyl)malonamide, exhibits excellent (≥ 96 %) silver(I) specificity.
- Full Text:
- Date Issued: 2001
Links between valley confinement, landforms and vegetation distribution in a semi-arid valley floor environment, Baviaanskloof, South Africa
- Authors: Smith-Adao, Lindie B
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/953 , vital:20006
- Description: Although a large body of international literature has advanced our understanding of river systems, a considerable amount of gaps exit in the knowledge of dryland systems. River systems reflect complex interactions between biophysical processes and patterns. Understanding how processes generate observed patterns and, in turn, how patterns influence processes is crucial to understanding river structure and function. It requires an interdisciplinary approach in both research and resulting applications. The aim of this thesis was to examine the relationship between valley confinement, fluvial style, valley floor morphology and vegetation in the semi-arid environment of the Baviaanskloof river catchment, South Africa. This interdisciplinary investigation used a mixed method approach that involved desktop analyses and field surveys to understand dynamics at multiple scales, from the whole catchment to local (site, reach and quadrat or sample plot) scales. The desktop analyses included historical rainfall patterns and climate extremes, aerial photograph time-series and remote sensing greenness indices, and the field surveys focussed on cross-valley landform profiles, groundwater depth levels, sediment size distribution and soil chemistry, and vegetation distribution patterns. Based on the integrative assessment of these techniques a framework was developed of the links between valley confinement, surface-groundwater interaction, hydrogeomorphic processes and landforms, vegetation and human activities. Study findings highlighted the fact that very strong links exist between these factors. In this semi-arid area water availability (groundwater and streamflow conditions) was the primary control on valley floor vegetation composition and patterning. One group of species was associated with the wetted channel reaches at confined and semi-confined valley settings, while the other was associated with dry bed channel reaches at unconfined valley settings. The analyses also indicated that the environmental variables which best explained the variation in vegetation at the differing geomorphic landforms were related to landform position (elevation and distance), sediment size (fine and coarse sand) and available phosphorus (i.e. human impacts). The different plants, in turn, also affected landforms through their influence on sediment erosion, transport and deposition. Specially, they build, maintained or modified geomorphic landforms at confined, semi-confined and unconfined valley settings across the valley floor. Valley confinement was a primary control influencing hydrogeomorphic processes and their associated landforms. Alluvial fans and terraces acted as critical additional controls at especially the unconfined valley setting. Implications for restoration efforts in the catchment included strategies that took cognisance of: active revegetation on floodplain surfaces related to former agricultural fields; channel switching associated with the highly dynamic and unpredictable nature of geomorphic features; unstable multi-thread braided channels in the unconfined valley setting; and the selection of representative monitoring sites.
- Full Text:
- Date Issued: 2016
- Authors: Smith-Adao, Lindie B
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/953 , vital:20006
- Description: Although a large body of international literature has advanced our understanding of river systems, a considerable amount of gaps exit in the knowledge of dryland systems. River systems reflect complex interactions between biophysical processes and patterns. Understanding how processes generate observed patterns and, in turn, how patterns influence processes is crucial to understanding river structure and function. It requires an interdisciplinary approach in both research and resulting applications. The aim of this thesis was to examine the relationship between valley confinement, fluvial style, valley floor morphology and vegetation in the semi-arid environment of the Baviaanskloof river catchment, South Africa. This interdisciplinary investigation used a mixed method approach that involved desktop analyses and field surveys to understand dynamics at multiple scales, from the whole catchment to local (site, reach and quadrat or sample plot) scales. The desktop analyses included historical rainfall patterns and climate extremes, aerial photograph time-series and remote sensing greenness indices, and the field surveys focussed on cross-valley landform profiles, groundwater depth levels, sediment size distribution and soil chemistry, and vegetation distribution patterns. Based on the integrative assessment of these techniques a framework was developed of the links between valley confinement, surface-groundwater interaction, hydrogeomorphic processes and landforms, vegetation and human activities. Study findings highlighted the fact that very strong links exist between these factors. In this semi-arid area water availability (groundwater and streamflow conditions) was the primary control on valley floor vegetation composition and patterning. One group of species was associated with the wetted channel reaches at confined and semi-confined valley settings, while the other was associated with dry bed channel reaches at unconfined valley settings. The analyses also indicated that the environmental variables which best explained the variation in vegetation at the differing geomorphic landforms were related to landform position (elevation and distance), sediment size (fine and coarse sand) and available phosphorus (i.e. human impacts). The different plants, in turn, also affected landforms through their influence on sediment erosion, transport and deposition. Specially, they build, maintained or modified geomorphic landforms at confined, semi-confined and unconfined valley settings across the valley floor. Valley confinement was a primary control influencing hydrogeomorphic processes and their associated landforms. Alluvial fans and terraces acted as critical additional controls at especially the unconfined valley setting. Implications for restoration efforts in the catchment included strategies that took cognisance of: active revegetation on floodplain surfaces related to former agricultural fields; channel switching associated with the highly dynamic and unpredictable nature of geomorphic features; unstable multi-thread braided channels in the unconfined valley setting; and the selection of representative monitoring sites.
- Full Text:
- Date Issued: 2016
A holistic approach in understanding the effects of dietary protein sources on the growth and reproductive development of farmed abalone, Haliotis midae
- Wu, Yu
- Authors: Wu, Yu
- Date: 2020
- Subjects: Abalones -- Nutrition , Abalones -- Reproduction , Abalones -- Growth , Abalone culture , Haliotis midae -- Nutrition , Haliotis midae -- Reproduction , Haliotis midae -- Growth , Haliotis midae fisheries
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167719 , vital:41506
- Description: The combination of fishmeal and soya in the formulated feed of farmed South African abalone, Haliotis midae, not only improved abalone growth, but also the sustainability of the compound diets by reducing the reliance on fishmeal. However, the presence of soya produced larger gonads compared to those of abalone fed kelp or single-source protein diets. There is an increasing drive to control sexual maturation and reduce undesirable spawning events in farmed abalone. However, the reasons for the reported effects of soya inclusion on the reproductive development of farmed H. midae remain unresolved. The aim of this research was to use a combination of techniques to contribute to the understanding of the relationship between growth, reproductive and nutritional physiology of farmed H. midae fed diets of varying protein sources. These techniques included stable isotope analysis (SIA), fatty acid analysis, gonad histological assessments and haemolymph sexsteroid hormone analysis. The objectives were to examine the allocation of protein and nutritional components to somatic and reproductive tissues. This study also included the first attempt to investigate the role that sex steroid hormones play during gametogenesis. Abalone (40 – 50 g abalone-1) were fed one of four diets: either a single-source protein-based diet, i.e., (1) fishmeal-only (FM) or (2) soya-only (S), or a combination diet of (3) fishmeal-soya (FM S) or (4) fishmeal-sunflower meal (FM SM). Sampling occurred in 45-day intervals over one year. Dietary protein source had an effect on the growth of abalone, with enhancements in growth linked to the combination of fishmeal and a plant-protein source. The fishmeal ingredient was the most utilised protein source throughout the temporal changes in protein allocation into somatic and reproductive tissue, followed by soya and then sunflower meal. The mean whole- body mass of abalone was significantly influenced by an interaction between time and dietary treatment, with average whole-body mass changing differently over time between treatments (RM-ANOVA, F(24, 96) = 2.13, p = 0.005). Overall, abalone that were fed FM S had higher mean whole-body mass values than abalone that were fed the single-protein based diets, while abalone that were fed FM SM were similar to animals from all dietary treatments (RMANOVA, F(3, 12) = 5.75, p = 0.01). Male abalone had significantly higher gonad bulk index (GBI) values compared to females (RM-ANOVA, F(1, 24) = 49.03, p < 0.001) and this was independent of dietary treatment. Within each sex, female abalone fed the FM S diet (15.92 ± 1.88 mm3 g-1) had significantly higher GBI values than abalone fed S (9.76 ± 1.08 mm3 g-1), while abalone fed FM (11.96 ± 1.71 mm3 g-1) and FM SM (11.90 ± 0.80 mm3 g-1) were similar to abalone from all other dietary treatments (Tukey’s HSD, p < 0.05). Male abalone fed the FM S (21.59 ± 2.10 mm3 g-1) and FM SM diet (19.30 ± 2.63 mm3 g-1) had similar GBI values and they were significantly higher than in abalone fed the S diet (14.74 ± 1.27 mm3 g-1), while abalone fed FM S had significantly higher GBI values than abalone that consumed the FM diet (15.08 ±1.63mm3 g-1) ( Tukey’s HSD, p < 0.05). Although sunflower meal was poorly utilised, it produced similar overall growth to abalone that were fed the FM S diets. Yet, feed conversion ratio values were significantly lower for abalone fed FM S (1.30 ± 0.13) compared to those in the other three treatments, with ratios ranging from 1.65 – 1.72 over the one-year. The fatty acid compositions of the somatic and gonadal tissues were similar between treatments (PERMANOVA, p = 0.21), while fatty acid composition was influenced by sampling day, tissue type and abalone sex (PERMANOVA, p < 0.05). The essential fatty acids (EFAs) eicosadienoic acid and a-linolenic acid were present in abalone tissue, but they were not detected in the diets, suggesting the important role that an alternate food source (e.g. farmed abalone also had access to diatoms) may have played and the ability that H. midae may have in converting long-chain polyunsaturated fatty acids from C18 precursors. A change in the abundance of EFAs in the gonad tissue during highest and lowest GBI values suggested that arachidonic, eicosapentaenoic, g-linolenic and linoleic acid were important in females, while eicosapentaenoic, eicosadienoic and a-linolenic acid were important for male reproductive development. Dietary protein sources had an effect on the frequency distribution of maturity stages, where females that were fed FM S produced more ripe gonads and more males that were fed FM SM contained testes that showed signs of ripeness over the one-year study. Although dietary protein influenced the sex steroid concentrations in females and males, exhibiting fluctuations throughout the one-year period, no distinct pattern linked to gametogenesis were observed. The results from this study illustrate: (1) the importance of conducting laboratory studies when implementing SIA and mixing models in aquaculture nutrition; (2) conducting nutritional studies on mature, grow-out abalone; and (3) assessing the importance of naturally occurring diatoms in their diet and their contribution to growth and reproduction. The novel contribution of this research towards abalone nutritional physiology, the implications of these findings to industry as well as potential considerations for future studies were addressed.
- Full Text:
- Date Issued: 2020
- Authors: Wu, Yu
- Date: 2020
- Subjects: Abalones -- Nutrition , Abalones -- Reproduction , Abalones -- Growth , Abalone culture , Haliotis midae -- Nutrition , Haliotis midae -- Reproduction , Haliotis midae -- Growth , Haliotis midae fisheries
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167719 , vital:41506
- Description: The combination of fishmeal and soya in the formulated feed of farmed South African abalone, Haliotis midae, not only improved abalone growth, but also the sustainability of the compound diets by reducing the reliance on fishmeal. However, the presence of soya produced larger gonads compared to those of abalone fed kelp or single-source protein diets. There is an increasing drive to control sexual maturation and reduce undesirable spawning events in farmed abalone. However, the reasons for the reported effects of soya inclusion on the reproductive development of farmed H. midae remain unresolved. The aim of this research was to use a combination of techniques to contribute to the understanding of the relationship between growth, reproductive and nutritional physiology of farmed H. midae fed diets of varying protein sources. These techniques included stable isotope analysis (SIA), fatty acid analysis, gonad histological assessments and haemolymph sexsteroid hormone analysis. The objectives were to examine the allocation of protein and nutritional components to somatic and reproductive tissues. This study also included the first attempt to investigate the role that sex steroid hormones play during gametogenesis. Abalone (40 – 50 g abalone-1) were fed one of four diets: either a single-source protein-based diet, i.e., (1) fishmeal-only (FM) or (2) soya-only (S), or a combination diet of (3) fishmeal-soya (FM S) or (4) fishmeal-sunflower meal (FM SM). Sampling occurred in 45-day intervals over one year. Dietary protein source had an effect on the growth of abalone, with enhancements in growth linked to the combination of fishmeal and a plant-protein source. The fishmeal ingredient was the most utilised protein source throughout the temporal changes in protein allocation into somatic and reproductive tissue, followed by soya and then sunflower meal. The mean whole- body mass of abalone was significantly influenced by an interaction between time and dietary treatment, with average whole-body mass changing differently over time between treatments (RM-ANOVA, F(24, 96) = 2.13, p = 0.005). Overall, abalone that were fed FM S had higher mean whole-body mass values than abalone that were fed the single-protein based diets, while abalone that were fed FM SM were similar to animals from all dietary treatments (RMANOVA, F(3, 12) = 5.75, p = 0.01). Male abalone had significantly higher gonad bulk index (GBI) values compared to females (RM-ANOVA, F(1, 24) = 49.03, p < 0.001) and this was independent of dietary treatment. Within each sex, female abalone fed the FM S diet (15.92 ± 1.88 mm3 g-1) had significantly higher GBI values than abalone fed S (9.76 ± 1.08 mm3 g-1), while abalone fed FM (11.96 ± 1.71 mm3 g-1) and FM SM (11.90 ± 0.80 mm3 g-1) were similar to abalone from all other dietary treatments (Tukey’s HSD, p < 0.05). Male abalone fed the FM S (21.59 ± 2.10 mm3 g-1) and FM SM diet (19.30 ± 2.63 mm3 g-1) had similar GBI values and they were significantly higher than in abalone fed the S diet (14.74 ± 1.27 mm3 g-1), while abalone fed FM S had significantly higher GBI values than abalone that consumed the FM diet (15.08 ±1.63mm3 g-1) ( Tukey’s HSD, p < 0.05). Although sunflower meal was poorly utilised, it produced similar overall growth to abalone that were fed the FM S diets. Yet, feed conversion ratio values were significantly lower for abalone fed FM S (1.30 ± 0.13) compared to those in the other three treatments, with ratios ranging from 1.65 – 1.72 over the one-year. The fatty acid compositions of the somatic and gonadal tissues were similar between treatments (PERMANOVA, p = 0.21), while fatty acid composition was influenced by sampling day, tissue type and abalone sex (PERMANOVA, p < 0.05). The essential fatty acids (EFAs) eicosadienoic acid and a-linolenic acid were present in abalone tissue, but they were not detected in the diets, suggesting the important role that an alternate food source (e.g. farmed abalone also had access to diatoms) may have played and the ability that H. midae may have in converting long-chain polyunsaturated fatty acids from C18 precursors. A change in the abundance of EFAs in the gonad tissue during highest and lowest GBI values suggested that arachidonic, eicosapentaenoic, g-linolenic and linoleic acid were important in females, while eicosapentaenoic, eicosadienoic and a-linolenic acid were important for male reproductive development. Dietary protein sources had an effect on the frequency distribution of maturity stages, where females that were fed FM S produced more ripe gonads and more males that were fed FM SM contained testes that showed signs of ripeness over the one-year study. Although dietary protein influenced the sex steroid concentrations in females and males, exhibiting fluctuations throughout the one-year period, no distinct pattern linked to gametogenesis were observed. The results from this study illustrate: (1) the importance of conducting laboratory studies when implementing SIA and mixing models in aquaculture nutrition; (2) conducting nutritional studies on mature, grow-out abalone; and (3) assessing the importance of naturally occurring diatoms in their diet and their contribution to growth and reproduction. The novel contribution of this research towards abalone nutritional physiology, the implications of these findings to industry as well as potential considerations for future studies were addressed.
- Full Text:
- Date Issued: 2020
Pyramidal deliberative democracy
- Authors: Danielsen, James
- Date: 2019
- Subjects: Democracy , Information technology -- Political aspects , Internet in public administration , Political participation -- Computer network resources , World politics
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/74502 , vital:30309
- Description: This dissertation has two main objectives. First, to outline an ICT-facilitated model of democracy called ‘pyramidal democracy’ that reconciles deliberative democracy with mass engagement. Second, to suggest how this model of democracy might engender the democratisation of the global economy and thus the provision of a basic level of economic security for all global citizens. At the core of the model is the pyramidal deliberative network, a means of organising citizens into small online deliberative groups and linking these groups together by means of an iterative process of delegate-selection and group-formation. The pyramidal network enables citizens to aggregate their preferences in a deliberative manner, and then project social power by authorizing the delegates at the top-tier of the pyramidal network to communicate their social demands to elected officials or to other points of authority. The envisioned outcome is the democratisation of the public sphere by means of the proliferation of deliberative networks in the government, market, and civil society spheres. Transnational pyramidal networks may make it feasible to instantiate a new citizen-based schema of global governance and, thereby, facilitate the reform of the United Nations and enable a transition towards global peace, sustainability, and distributive justice. Distributive justice might be achieved by means of implementing the six components of a democratised economy: participatory budgeting, fee-and-dividend taxes, a basic income, monetary reform, workplace democracy, and the sharing economy. Taken together, these components might enable the universal provision of a social minimum – a universal basic income sufficient for basic security and real freedom. Taken to its logical conclusion, a democratised economy may also enable a transition towards a post-scarcity economic order characterised by a maximal stock of humanmade and natural capital that would not exceed the sustainable carrying capacity of the earth.
- Full Text:
- Date Issued: 2019
- Authors: Danielsen, James
- Date: 2019
- Subjects: Democracy , Information technology -- Political aspects , Internet in public administration , Political participation -- Computer network resources , World politics
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/74502 , vital:30309
- Description: This dissertation has two main objectives. First, to outline an ICT-facilitated model of democracy called ‘pyramidal democracy’ that reconciles deliberative democracy with mass engagement. Second, to suggest how this model of democracy might engender the democratisation of the global economy and thus the provision of a basic level of economic security for all global citizens. At the core of the model is the pyramidal deliberative network, a means of organising citizens into small online deliberative groups and linking these groups together by means of an iterative process of delegate-selection and group-formation. The pyramidal network enables citizens to aggregate their preferences in a deliberative manner, and then project social power by authorizing the delegates at the top-tier of the pyramidal network to communicate their social demands to elected officials or to other points of authority. The envisioned outcome is the democratisation of the public sphere by means of the proliferation of deliberative networks in the government, market, and civil society spheres. Transnational pyramidal networks may make it feasible to instantiate a new citizen-based schema of global governance and, thereby, facilitate the reform of the United Nations and enable a transition towards global peace, sustainability, and distributive justice. Distributive justice might be achieved by means of implementing the six components of a democratised economy: participatory budgeting, fee-and-dividend taxes, a basic income, monetary reform, workplace democracy, and the sharing economy. Taken together, these components might enable the universal provision of a social minimum – a universal basic income sufficient for basic security and real freedom. Taken to its logical conclusion, a democratised economy may also enable a transition towards a post-scarcity economic order characterised by a maximal stock of humanmade and natural capital that would not exceed the sustainable carrying capacity of the earth.
- Full Text:
- Date Issued: 2019
The use of hydrological information to improve flood management-integrated hydrological modelling of the Zambezi River basin
- Vilanculos, Agostinho Chuquelane Fadulo
- Authors: Vilanculos, Agostinho Chuquelane Fadulo
- Date: 2015
- Subjects: Hydrologic models -- Zambezi River Watershed , Watershed management -- Zambezi River Watershed , Water resources development -- Zambezi River Watershed , Flood control -- Zambezi River Watershed , Flood forecasting -- Zambezi River Watershed , Rain gauges -- Zambezi River Watershed
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6054 , http://hdl.handle.net/10962/d1018915
- Description: The recent high profile flooding events – that have occurred in many parts of the world – have drawn attention to the need for new and improved methods for water resources assessment, water management and the modelling of large-scale flooding events. In the case of the Zambezi Basin, a review of the 2000 and 2001 floods identified the need for tools to enable hydrologists to assess and predict daily stream flow and identify the areas that are likely to be affected by flooding. As a way to address the problem, a methodology was set up to derive catchment soil moisture statistics from Earth Observation (EO) data and to study the improvements brought about by an assimilation of this information into hydrological models for improving reservoir management in a data scarce environment. Rainfall data were obtained from the FEWSNet Web site and computed by the National Oceanic and Atmospheric Administration Climatic Prediction Center (NOAA/CPC). These datasets were processed and used to monitor rainfall variability and subsequently fed into a hydrological model to predict the daily flows for the Zambezi River Basin. The hydrological model used was the Geospatial Stream Flow Model (GeoSFM), developed by the United States Geological Survey (USGS). GeoSFM is a spatially semi-distributed physically-based hydrological model, parameterised using spatially distributed topographic data, soil characteristics and land cover data sets available globally from both Remote Sensing and in situ sources. The Satellite rainfall data were validated against data from twenty (20) rainfall gauges located on the Lower Zambezi. However, at several rain gauge stations (especially those with complex topography, which tended to experience high rainfall spatial variability), there was no direct correlation between the satellite estimates and the ground data as recorded in daily time steps. The model was calibrated for seven gauging stations. The calibrated model performed quite well at seven selected locations (R2=0.66 to 0.90, CE=0.51 to 0.88, RSR=0.35 to 0.69, PBIAS=−4.5 to 7.5). The observed data were obtained from the National Water Agencies of the riparian countries. After GeoSFM calibration, the model generated an integration of the flows into a reservoir and hydropower model to optimise the operation of Kariba and Cahora Bassa dams. The Kariba and Cahora Bassa dams were selected because this study considers these two dams as the major infrastructures for controlling and alleviating floods in the Zambezi River Basin. Other dams (such as the Kafue and Itezhi-Thezi) were recognised in terms of their importance but including them was beyond the scope of this study because of financial and time constraints. The licence of the reservoir model was limited to one year for the same reason. The reservoir model used was the MIKE BASIN, a professional engineering software package and quasi-steady-state mass balance modelling tool for integrated river basin and management, developed by the Denmark Hydraulic Institute (DHI) in 2003. The model was parameterised by the geometry of the reservoir basin (level, area, volume relationships) and by the discharge-level (Q-h) relationship of the dam spillways. The integrated modelling system simulated the daily flow variation for all Zambezi River sub-basins between 1998 and 2008 and validated between 2009 and 2011. The resulting streamflows have been expressed in terms of hydrograph comparisons between simulated and observed flow values at the four gauging stations located downstream of Cahora Bassa dam. The integrated model performed well, between observed and forecast streamflows, at four selected gauging stations (R2=0.53 to 0.90, CE=0.50 to 0.80, RSR=0.49 to 0.69, PBIAS=−2.10 to 4.8). From the results of integrated modelling, it was observed that both Kariba and Cahora Bassa are currently being operated based on the maximum rule curve and both remain focused on maximising hydropower production and ensuring dam safety rather than other potential influences by the Zambezi River (such as flood control downstream – where the communities are located – and environmental issues). In addition, the flood mapping analysis demonstrated that the Cahora Bassa dam plays an important part in flood mitigation downstream of the dams. In the absence of optimisation of flow releases from both the Kariba and Cahora Bassa dams, in additional to the contribution of any other tributaries located downstream of the dams, the impact of flooding can be severe. As such, this study has developed new approaches for flood monitoring downstream of the Zambezi Basin, through the application of an integrated modelling system. The modelling system consists of: predicting daily streamflow (using the calibrated GeoSFM), then feeding the predicted streamflow into MIKE BASIN (for checking the operating rules) and to optimise the releases. Therefore, before releases are made, the flood maps can be used as a decision-making tool to both assess the impact of each level of release downstream and to identify the communities likely to be affected by the flood – this ensures that the necessary warnings can be issued before flooding occurs. Finally an integrated flood management tool was proposed – to host the results produced by the integrated system – which would then be accessible for assessment by the different users. These results were expressed in terms of water level (m). Four discharge-level (Q-h) relationships were developed for converting the simulated flow into water level at four selected sites downstream of Cahora Bassa dam – namely: Cahora Bassa dam site, Tete (E-320), Caia (E-291) and Marromeu (E-285). However, the uncertainties in these predictions suggested that improved monitoring systems may be achieved if data access at appropriate scale and quality was improved.
- Full Text:
- Date Issued: 2015
- Authors: Vilanculos, Agostinho Chuquelane Fadulo
- Date: 2015
- Subjects: Hydrologic models -- Zambezi River Watershed , Watershed management -- Zambezi River Watershed , Water resources development -- Zambezi River Watershed , Flood control -- Zambezi River Watershed , Flood forecasting -- Zambezi River Watershed , Rain gauges -- Zambezi River Watershed
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6054 , http://hdl.handle.net/10962/d1018915
- Description: The recent high profile flooding events – that have occurred in many parts of the world – have drawn attention to the need for new and improved methods for water resources assessment, water management and the modelling of large-scale flooding events. In the case of the Zambezi Basin, a review of the 2000 and 2001 floods identified the need for tools to enable hydrologists to assess and predict daily stream flow and identify the areas that are likely to be affected by flooding. As a way to address the problem, a methodology was set up to derive catchment soil moisture statistics from Earth Observation (EO) data and to study the improvements brought about by an assimilation of this information into hydrological models for improving reservoir management in a data scarce environment. Rainfall data were obtained from the FEWSNet Web site and computed by the National Oceanic and Atmospheric Administration Climatic Prediction Center (NOAA/CPC). These datasets were processed and used to monitor rainfall variability and subsequently fed into a hydrological model to predict the daily flows for the Zambezi River Basin. The hydrological model used was the Geospatial Stream Flow Model (GeoSFM), developed by the United States Geological Survey (USGS). GeoSFM is a spatially semi-distributed physically-based hydrological model, parameterised using spatially distributed topographic data, soil characteristics and land cover data sets available globally from both Remote Sensing and in situ sources. The Satellite rainfall data were validated against data from twenty (20) rainfall gauges located on the Lower Zambezi. However, at several rain gauge stations (especially those with complex topography, which tended to experience high rainfall spatial variability), there was no direct correlation between the satellite estimates and the ground data as recorded in daily time steps. The model was calibrated for seven gauging stations. The calibrated model performed quite well at seven selected locations (R2=0.66 to 0.90, CE=0.51 to 0.88, RSR=0.35 to 0.69, PBIAS=−4.5 to 7.5). The observed data were obtained from the National Water Agencies of the riparian countries. After GeoSFM calibration, the model generated an integration of the flows into a reservoir and hydropower model to optimise the operation of Kariba and Cahora Bassa dams. The Kariba and Cahora Bassa dams were selected because this study considers these two dams as the major infrastructures for controlling and alleviating floods in the Zambezi River Basin. Other dams (such as the Kafue and Itezhi-Thezi) were recognised in terms of their importance but including them was beyond the scope of this study because of financial and time constraints. The licence of the reservoir model was limited to one year for the same reason. The reservoir model used was the MIKE BASIN, a professional engineering software package and quasi-steady-state mass balance modelling tool for integrated river basin and management, developed by the Denmark Hydraulic Institute (DHI) in 2003. The model was parameterised by the geometry of the reservoir basin (level, area, volume relationships) and by the discharge-level (Q-h) relationship of the dam spillways. The integrated modelling system simulated the daily flow variation for all Zambezi River sub-basins between 1998 and 2008 and validated between 2009 and 2011. The resulting streamflows have been expressed in terms of hydrograph comparisons between simulated and observed flow values at the four gauging stations located downstream of Cahora Bassa dam. The integrated model performed well, between observed and forecast streamflows, at four selected gauging stations (R2=0.53 to 0.90, CE=0.50 to 0.80, RSR=0.49 to 0.69, PBIAS=−2.10 to 4.8). From the results of integrated modelling, it was observed that both Kariba and Cahora Bassa are currently being operated based on the maximum rule curve and both remain focused on maximising hydropower production and ensuring dam safety rather than other potential influences by the Zambezi River (such as flood control downstream – where the communities are located – and environmental issues). In addition, the flood mapping analysis demonstrated that the Cahora Bassa dam plays an important part in flood mitigation downstream of the dams. In the absence of optimisation of flow releases from both the Kariba and Cahora Bassa dams, in additional to the contribution of any other tributaries located downstream of the dams, the impact of flooding can be severe. As such, this study has developed new approaches for flood monitoring downstream of the Zambezi Basin, through the application of an integrated modelling system. The modelling system consists of: predicting daily streamflow (using the calibrated GeoSFM), then feeding the predicted streamflow into MIKE BASIN (for checking the operating rules) and to optimise the releases. Therefore, before releases are made, the flood maps can be used as a decision-making tool to both assess the impact of each level of release downstream and to identify the communities likely to be affected by the flood – this ensures that the necessary warnings can be issued before flooding occurs. Finally an integrated flood management tool was proposed – to host the results produced by the integrated system – which would then be accessible for assessment by the different users. These results were expressed in terms of water level (m). Four discharge-level (Q-h) relationships were developed for converting the simulated flow into water level at four selected sites downstream of Cahora Bassa dam – namely: Cahora Bassa dam site, Tete (E-320), Caia (E-291) and Marromeu (E-285). However, the uncertainties in these predictions suggested that improved monitoring systems may be achieved if data access at appropriate scale and quality was improved.
- Full Text:
- Date Issued: 2015
Structural and synthetic investigations of diterpenoid natural products from southern African marine invertebrates
- Authors: Gray, Christopher Anthony
- Date: 2003
- Subjects: Ethyl acetoacetate Diterpenes Limpets -- South Africa Natural products -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4349 , http://hdl.handle.net/10962/d1005014
- Description: This thesis is divided into two parts. The first part (Chapter Two) documents a bioassay guided investigation of the ethyl acetate extracts of four marine invertebrates from Mozambique (an Irciniid sponge, a Haliclona sp. sponge, an ascidian tentatively identified as Diplosoma sp., and the soft coral Cladiella kashmani). Eight known compounds [ilimaquinone (2.1), renierone (2.7), N-formyl-1,2-dihydrorenierone (2.8), 1,6-dimethyl-7-methoxy-5,8-dihydroisoquinoline-5,8-dione (2.9), mimosamycin (2.10) 7Z-allylidene-5-hydroxy-7,7a-dihydro-2H-cyclopenta[b]pyran-6-one (2.11), flaccidoxide (2.18) and 11S,12S-epoxycembra-1Z,3E,7E-trien-14S-ol (2.19)] and a new diterpene [13S,14R-diacetoxy-11S,12R-epoxycembra-1Z,3E,7E-triene (2.20)] were isolated and identified using standard spectroscopic techniques. Anomalies in the published spectral data of 2.1 and 2.8 were exposed and corrected, and the absolute stereochemistry of the cembrane diterpenes 2.18 and 2.20 established using the modified Mosher’s method. The comparative activities of the nine natural products against four cancer cell lines (A549, LOX, OVCAR3, SNB19) are reported. The second part of the thesis (Chapter Three – Chapter Six) is concerned with an ecological, structural and synthetic study of diterpenes from the endemic South African pulmonate limpet Trimusculus costatus. Two new labdane diterpenes [6b,7a-diacetoxylabda-8,13E-dien-15-ol (3.10) and 2a,6b,7a-triacetoxylabda-8,13E-dien-15-ol (3.11)] were isolated from T. costatus and evaluated for anti-feeding activity against the common predatory fish Pomadasys commersonnii. A strategy for the semi-synthesis of 3.10 from rhinocerotinoic acid (4.14), a diterpene reportedly present in the ubiquitous South African shrub Elytropappus rhinocerotis, was devised in order to allow further bioactivity tests to be performed and unequivocally assign the unknown absolute stereochemistry of the T. costatus metabolites. Attempts to isolate rhinocerotinoic acid from local specimens of Elytropappus rhinocerotis were unsuccessful, and as the repetition of a published synthesis of 4.14 from (-)-sclareol (4.15) gave rhinocerotinoic acid in unacceptably low yields with poor stereoselectivity, an improved synthesis of 4.14 is presented. Comprehensive studies using hispanone (5.1) as a model compound showed that 6,7-dioxygenated labda-8-enes could be prepared from compounds possessing a 7-oxo-labda-8-ene skeleton with some degree of stereocontrol. In the process, fourteen new hispanone analogues were prepared and most of these were tested for activity in a suite of ten agro-chemical assays. The novel compound 7b-hydroxy-9a-carbonitrile-15,16-epoxylabda-13(16),14-dien-6-one (5.34) exhibited significant activity against the crop fungus Phytophthora infestans and is currently being subjected to further agro-chemical tests. Unfortunately, the results from the oxygenation study performed on the model compound 5.1 could not be directly extrapolated to rhinocerotinoic acid. Attempts to prepare the naturally occurring 3.10 from 4.14 via an alternative route were unsuccessful but yielded an analogue of 3.10 in which the substituents at C-6 and C-7 are in a diequatorial rather than a diaxial configuration.
- Full Text:
- Date Issued: 2003
- Authors: Gray, Christopher Anthony
- Date: 2003
- Subjects: Ethyl acetoacetate Diterpenes Limpets -- South Africa Natural products -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4349 , http://hdl.handle.net/10962/d1005014
- Description: This thesis is divided into two parts. The first part (Chapter Two) documents a bioassay guided investigation of the ethyl acetate extracts of four marine invertebrates from Mozambique (an Irciniid sponge, a Haliclona sp. sponge, an ascidian tentatively identified as Diplosoma sp., and the soft coral Cladiella kashmani). Eight known compounds [ilimaquinone (2.1), renierone (2.7), N-formyl-1,2-dihydrorenierone (2.8), 1,6-dimethyl-7-methoxy-5,8-dihydroisoquinoline-5,8-dione (2.9), mimosamycin (2.10) 7Z-allylidene-5-hydroxy-7,7a-dihydro-2H-cyclopenta[b]pyran-6-one (2.11), flaccidoxide (2.18) and 11S,12S-epoxycembra-1Z,3E,7E-trien-14S-ol (2.19)] and a new diterpene [13S,14R-diacetoxy-11S,12R-epoxycembra-1Z,3E,7E-triene (2.20)] were isolated and identified using standard spectroscopic techniques. Anomalies in the published spectral data of 2.1 and 2.8 were exposed and corrected, and the absolute stereochemistry of the cembrane diterpenes 2.18 and 2.20 established using the modified Mosher’s method. The comparative activities of the nine natural products against four cancer cell lines (A549, LOX, OVCAR3, SNB19) are reported. The second part of the thesis (Chapter Three – Chapter Six) is concerned with an ecological, structural and synthetic study of diterpenes from the endemic South African pulmonate limpet Trimusculus costatus. Two new labdane diterpenes [6b,7a-diacetoxylabda-8,13E-dien-15-ol (3.10) and 2a,6b,7a-triacetoxylabda-8,13E-dien-15-ol (3.11)] were isolated from T. costatus and evaluated for anti-feeding activity against the common predatory fish Pomadasys commersonnii. A strategy for the semi-synthesis of 3.10 from rhinocerotinoic acid (4.14), a diterpene reportedly present in the ubiquitous South African shrub Elytropappus rhinocerotis, was devised in order to allow further bioactivity tests to be performed and unequivocally assign the unknown absolute stereochemistry of the T. costatus metabolites. Attempts to isolate rhinocerotinoic acid from local specimens of Elytropappus rhinocerotis were unsuccessful, and as the repetition of a published synthesis of 4.14 from (-)-sclareol (4.15) gave rhinocerotinoic acid in unacceptably low yields with poor stereoselectivity, an improved synthesis of 4.14 is presented. Comprehensive studies using hispanone (5.1) as a model compound showed that 6,7-dioxygenated labda-8-enes could be prepared from compounds possessing a 7-oxo-labda-8-ene skeleton with some degree of stereocontrol. In the process, fourteen new hispanone analogues were prepared and most of these were tested for activity in a suite of ten agro-chemical assays. The novel compound 7b-hydroxy-9a-carbonitrile-15,16-epoxylabda-13(16),14-dien-6-one (5.34) exhibited significant activity against the crop fungus Phytophthora infestans and is currently being subjected to further agro-chemical tests. Unfortunately, the results from the oxygenation study performed on the model compound 5.1 could not be directly extrapolated to rhinocerotinoic acid. Attempts to prepare the naturally occurring 3.10 from 4.14 via an alternative route were unsuccessful but yielded an analogue of 3.10 in which the substituents at C-6 and C-7 are in a diequatorial rather than a diaxial configuration.
- Full Text:
- Date Issued: 2003
The classification and phylogeny of the Psocoptera
- Authors: Smithers, Courtenay Neville
- Date: 1970
- Subjects: Psocoptera , Insects -- Classification
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5884 , http://hdl.handle.net/10962/d1013232
- Description: This work provides a phylogenetic classification of the insect order PSOCOPTERA. Some of the problems involved, mainly arising from lack of adequate published data, are pointed out and work carried out to overcome them is indicated in a short introductory chapter (Chapter I). This consisted of accummulating data on the genera from published texts and illustrations, adding data from the study of fresh material or material held in collections and compiling generic definitions in adequate detail where possible. Chapter II gives a general description of the Psocoptera together with brief background information on their biology. As considerable changes are proposed in the classification of the order (in Chapter VII) the classification in use at present is set out for comparison to generic level and a brief history of systematic work on the order is given {Chapter III). The data necessary for a discussion of the phylogeny is presented in the series of definitions of genera and suprageneric groups in Chapter IV. Data on fossil forms is given in Chapter V. The principles of phylogenetic study are briefly discussed in Chapter VI and the important question of the relatively primitive or advanced condition of characters in the order is discussed. The monophyly of the order and the relationships between genera are established using Hennig's system and the results are set out in discussion and dendrogram. On the basis of the relationships so established a classification of the order is proposed which is considered to be practical and to reflect evolutionary history of the group. (Chapter. VII.) Comments on the distribution of the Psocoptera are made in Chapter VIII and it is suggested that, despite inadequacy of data, a consideration of the distributions supports the proposed classification in general terms. A general discussion follows and references and figures are included. An appendix provides a practical up-to-date key to the genera of the order.
- Full Text:
- Date Issued: 1970
- Authors: Smithers, Courtenay Neville
- Date: 1970
- Subjects: Psocoptera , Insects -- Classification
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5884 , http://hdl.handle.net/10962/d1013232
- Description: This work provides a phylogenetic classification of the insect order PSOCOPTERA. Some of the problems involved, mainly arising from lack of adequate published data, are pointed out and work carried out to overcome them is indicated in a short introductory chapter (Chapter I). This consisted of accummulating data on the genera from published texts and illustrations, adding data from the study of fresh material or material held in collections and compiling generic definitions in adequate detail where possible. Chapter II gives a general description of the Psocoptera together with brief background information on their biology. As considerable changes are proposed in the classification of the order (in Chapter VII) the classification in use at present is set out for comparison to generic level and a brief history of systematic work on the order is given {Chapter III). The data necessary for a discussion of the phylogeny is presented in the series of definitions of genera and suprageneric groups in Chapter IV. Data on fossil forms is given in Chapter V. The principles of phylogenetic study are briefly discussed in Chapter VI and the important question of the relatively primitive or advanced condition of characters in the order is discussed. The monophyly of the order and the relationships between genera are established using Hennig's system and the results are set out in discussion and dendrogram. On the basis of the relationships so established a classification of the order is proposed which is considered to be practical and to reflect evolutionary history of the group. (Chapter. VII.) Comments on the distribution of the Psocoptera are made in Chapter VIII and it is suggested that, despite inadequacy of data, a consideration of the distributions supports the proposed classification in general terms. A general discussion follows and references and figures are included. An appendix provides a practical up-to-date key to the genera of the order.
- Full Text:
- Date Issued: 1970
Study of titanium, tantalum and chromium catalysts for use in industrial transformations
- Authors: Tau, Prudence Lerato
- Date: 2007
- Subjects: Titanium Tantalum Phthalocyanines Electrochemistry Photochemotherapy Chromium Spectrum analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4363 , http://hdl.handle.net/10962/d1005028
- Description: PART A The syntheses, spectroscopic and electrochemical characterisation of a series of titanium and tantalum phthalocyanine complexes are reported. The complexes are unsubstituted and substituted at either the peripheral or non-peripheral positions with sulphonates, aryloxy, arylthio or amino groups. The complexes mostly exhibit Qbands in the near-infrared region as well as interesting properties in different solvents. The interaction of differently sulphonated titanium and tantalum phthalocyanine complexes with methyl viologen (MV[superscript 2+]), and hence the stoichiometry and association constants are evaluated. Detailed photophysicochemical properties of the complexes were investigated and are for the first time presented with fluorescence lifetimes easily obtained from fluorescence quenching studies. The transformation of 1-hexene photocatalysed by aryloxy- and arylthio-appended complexes is also presented for the first time. The electrochemical properties of the complexes are unknown and are thus presented. Cyclic (CV) and square wave (SWV) voltammetries, chronocoulometry and spectroelectrochemistry are employed in the study of the complexes. Two oneelectron reductions and a simultaneous 4-electron reduction are observed for the unsubstituted Cl[subscript 3]TaPc. Reduction occurs first at the metal followed by ring-based processes. The tetra- and octa-substituted derivatives however exhibit peculiar electrochemical behaviour where a multi-electron transfer process occurs for complexes bearing certain substituents. For all complexes, the first two reductions are metal-based followed by ring-based processes. A comparative study of the electrocatalytic activities of the complexes towards the oxidation of nitrite is also investigated. The complexes are immobilised onto a glassy carbon electrode either by drop-dry or electropolymerisation methods. All the modified electrodes exhibit improved electrocatalytic oxidation of nitrite than the unmodified electrodes by a twoelectron mechanism producing nitrate ions. Catalytic currents are enhanced and nitrite overpotential reduced to ~ 0.60 V. Kinetic parameters are determined for all complexes and a mechanism is proposed. PART B: The syntheses and electrochemical characterisation of chromium and titanium complexes for the selective trimerisation of ethylene to 1-hexene are presented. The synthesis of the chromium complex requires simple steps while tedious steps are used for the air-sensitive titanium complex. The spectroscopic interaction of the chromium complex with the co-catalyst methylaluminoxane is investigated. The complexes are characterised by electrochemical methods such as cyclic voltammetry and spectroelectrochemistry.
- Full Text:
- Date Issued: 2007
- Authors: Tau, Prudence Lerato
- Date: 2007
- Subjects: Titanium Tantalum Phthalocyanines Electrochemistry Photochemotherapy Chromium Spectrum analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4363 , http://hdl.handle.net/10962/d1005028
- Description: PART A The syntheses, spectroscopic and electrochemical characterisation of a series of titanium and tantalum phthalocyanine complexes are reported. The complexes are unsubstituted and substituted at either the peripheral or non-peripheral positions with sulphonates, aryloxy, arylthio or amino groups. The complexes mostly exhibit Qbands in the near-infrared region as well as interesting properties in different solvents. The interaction of differently sulphonated titanium and tantalum phthalocyanine complexes with methyl viologen (MV[superscript 2+]), and hence the stoichiometry and association constants are evaluated. Detailed photophysicochemical properties of the complexes were investigated and are for the first time presented with fluorescence lifetimes easily obtained from fluorescence quenching studies. The transformation of 1-hexene photocatalysed by aryloxy- and arylthio-appended complexes is also presented for the first time. The electrochemical properties of the complexes are unknown and are thus presented. Cyclic (CV) and square wave (SWV) voltammetries, chronocoulometry and spectroelectrochemistry are employed in the study of the complexes. Two oneelectron reductions and a simultaneous 4-electron reduction are observed for the unsubstituted Cl[subscript 3]TaPc. Reduction occurs first at the metal followed by ring-based processes. The tetra- and octa-substituted derivatives however exhibit peculiar electrochemical behaviour where a multi-electron transfer process occurs for complexes bearing certain substituents. For all complexes, the first two reductions are metal-based followed by ring-based processes. A comparative study of the electrocatalytic activities of the complexes towards the oxidation of nitrite is also investigated. The complexes are immobilised onto a glassy carbon electrode either by drop-dry or electropolymerisation methods. All the modified electrodes exhibit improved electrocatalytic oxidation of nitrite than the unmodified electrodes by a twoelectron mechanism producing nitrate ions. Catalytic currents are enhanced and nitrite overpotential reduced to ~ 0.60 V. Kinetic parameters are determined for all complexes and a mechanism is proposed. PART B: The syntheses and electrochemical characterisation of chromium and titanium complexes for the selective trimerisation of ethylene to 1-hexene are presented. The synthesis of the chromium complex requires simple steps while tedious steps are used for the air-sensitive titanium complex. The spectroscopic interaction of the chromium complex with the co-catalyst methylaluminoxane is investigated. The complexes are characterised by electrochemical methods such as cyclic voltammetry and spectroelectrochemistry.
- Full Text:
- Date Issued: 2007
A critical realist exploration of the culture of resistance in educational technology integration practices at a South African university
- Authors: Tshuma, Nompilo
- Date: 2019
- Subjects: Critical realism , Educational technology -- South Africa , Education, Higher -- Effect of technological innovations on -- South Africa , College teachers -- South Africa , College teaching -- Sociological aspects -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/72318 , vital:30033
- Description: This thesis seeks to address a number of troubling concerns related to research and practice in the field of educational technology in South African higher education. Firstly, educational technology research has been criticised for a lack of theoretical rigour resulting in perspectives that are tightly focused mostly on practice but fail to adequately interrogate the socio-political complexities of integrating educational technology. Secondly, while research in the field has been criticised for failing to adequately contextualise the study of educational technology, it also fails to interrogate the impact of colonial legacies and Western-developed technologies on integration practices. Thirdly, there seems to be a disconnect between academics’ practices and choices with educational technology, and the expectations and assumptions of educational technologists. As such, this thesis predominantly follows inductive reasoning where literature and theory are applied to the empirical situation retrospectively in order to avoid the potential influences and biases of mostly Western-driven discourses on educational technology integration practices. Critical realism is used to ‘underlabour’ this study. This meta-theory asserts that there are multiple perspectives of an independent reality, and the work of research is to use these perspectives to draw closer to an understanding of that reality. As such, it allows me to interrogate my perspectives firstly, and secondly those of my research participants, about factors that constrain educational technology integration in the South African context through the use of theory (abstract concepts) and data (research participants’ multiple perspectives). However, critical realism is somewhat cautious in how to access this reality. Therefore, a critical ethnographic epistemology is employed to strengthen critical realism’s aim of accessing knowledge. A critical epistemology emphasises exposing hidden power structures, value judgements as well as self-knowledge and reflexivity. The thesis thus shows how a critical realist ontology could be complemented by a critical ethnographic methodology, particularly in critically-orientated research that has an emancipatory focus which seeks to uncover the socio-political context within which educational technology practices take place. A key argument is that critical realism can be employed as an ontological underlabourer for critical research because of: 1) its immanent critique of traditionally-accepted philosophies, 2) its emphasis on critique of our knowledge claims and value judgements, 3) its insistence that knowledge of the social world necessarily precedes emancipation, and 4) its different conceptions of power (oppressive power and transformatory power). This critical ethnographic research is conducted in a South African university with eight female academics. Data collection is in the form of interviews, observations and reflections, as well as informal and work-related interactions. At each data collection moment, I have had to be reflexively aware of my positionality as an educational technologist, the impact of a colonially-motivated methodology and an ethically-aware approach that seeks to put the needs of the research participants first. Critical ethnography’s meaning-making and critical realism’s abduction and retroduction are used to analyse and make sense of the data. In my attempt to contextualise the study’s findings, I first uncover structural forces and their impact on the academic role before attempting to correlate this with educational technology practices. The study’s findings point to two main structural forces in the socio-political context of South African higher education: the teaching/research tension and the elevation of one dominant culture. In terms of the teaching/research tension, the female academics in this study have to balance the urgent teaching function with the valued research function. They struggle to find this balance because of ambiguous messages from different structures, their passion for teaching, oppressive departmental dynamics and the pressures of their career trajectory. The elevation of one dominant culture is demonstrated through both oppressive cultural practices and untransformed curricula. The study shows that academics mitigate these structural constraints mostly through subtle every day resistance that seeks to mitigate their effect on both the academics and, where applicable, their students. Archer’s morphogenetic/morphostatic cycle is used retrospectively, in response to fieldwork, to conceptualise why this resistance comes about. A resistance framework developed using Archer is then used to understand educational technology choices and practices. The results of the research show that while academics are often pictured as resistant to technology as a response to different barriers, they actually often employ technology to resist structural forces. That is, with this thesis I show that there is a focus on resistance with technology rather than resistance to technology. The study shows how the research participants resist structural forces (teaching tension and dominant culture) by using technology to create safe and responsive learning spaces. As such, this thesis challenges educational technologists to re-think the way they support academics by recommending support strategies that acknowledge both the structural forces in the South African higher education context, as well as the culture of resistance, both of which impact academics’ educational technology choices and practices.
- Full Text:
- Date Issued: 2019
- Authors: Tshuma, Nompilo
- Date: 2019
- Subjects: Critical realism , Educational technology -- South Africa , Education, Higher -- Effect of technological innovations on -- South Africa , College teachers -- South Africa , College teaching -- Sociological aspects -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/72318 , vital:30033
- Description: This thesis seeks to address a number of troubling concerns related to research and practice in the field of educational technology in South African higher education. Firstly, educational technology research has been criticised for a lack of theoretical rigour resulting in perspectives that are tightly focused mostly on practice but fail to adequately interrogate the socio-political complexities of integrating educational technology. Secondly, while research in the field has been criticised for failing to adequately contextualise the study of educational technology, it also fails to interrogate the impact of colonial legacies and Western-developed technologies on integration practices. Thirdly, there seems to be a disconnect between academics’ practices and choices with educational technology, and the expectations and assumptions of educational technologists. As such, this thesis predominantly follows inductive reasoning where literature and theory are applied to the empirical situation retrospectively in order to avoid the potential influences and biases of mostly Western-driven discourses on educational technology integration practices. Critical realism is used to ‘underlabour’ this study. This meta-theory asserts that there are multiple perspectives of an independent reality, and the work of research is to use these perspectives to draw closer to an understanding of that reality. As such, it allows me to interrogate my perspectives firstly, and secondly those of my research participants, about factors that constrain educational technology integration in the South African context through the use of theory (abstract concepts) and data (research participants’ multiple perspectives). However, critical realism is somewhat cautious in how to access this reality. Therefore, a critical ethnographic epistemology is employed to strengthen critical realism’s aim of accessing knowledge. A critical epistemology emphasises exposing hidden power structures, value judgements as well as self-knowledge and reflexivity. The thesis thus shows how a critical realist ontology could be complemented by a critical ethnographic methodology, particularly in critically-orientated research that has an emancipatory focus which seeks to uncover the socio-political context within which educational technology practices take place. A key argument is that critical realism can be employed as an ontological underlabourer for critical research because of: 1) its immanent critique of traditionally-accepted philosophies, 2) its emphasis on critique of our knowledge claims and value judgements, 3) its insistence that knowledge of the social world necessarily precedes emancipation, and 4) its different conceptions of power (oppressive power and transformatory power). This critical ethnographic research is conducted in a South African university with eight female academics. Data collection is in the form of interviews, observations and reflections, as well as informal and work-related interactions. At each data collection moment, I have had to be reflexively aware of my positionality as an educational technologist, the impact of a colonially-motivated methodology and an ethically-aware approach that seeks to put the needs of the research participants first. Critical ethnography’s meaning-making and critical realism’s abduction and retroduction are used to analyse and make sense of the data. In my attempt to contextualise the study’s findings, I first uncover structural forces and their impact on the academic role before attempting to correlate this with educational technology practices. The study’s findings point to two main structural forces in the socio-political context of South African higher education: the teaching/research tension and the elevation of one dominant culture. In terms of the teaching/research tension, the female academics in this study have to balance the urgent teaching function with the valued research function. They struggle to find this balance because of ambiguous messages from different structures, their passion for teaching, oppressive departmental dynamics and the pressures of their career trajectory. The elevation of one dominant culture is demonstrated through both oppressive cultural practices and untransformed curricula. The study shows that academics mitigate these structural constraints mostly through subtle every day resistance that seeks to mitigate their effect on both the academics and, where applicable, their students. Archer’s morphogenetic/morphostatic cycle is used retrospectively, in response to fieldwork, to conceptualise why this resistance comes about. A resistance framework developed using Archer is then used to understand educational technology choices and practices. The results of the research show that while academics are often pictured as resistant to technology as a response to different barriers, they actually often employ technology to resist structural forces. That is, with this thesis I show that there is a focus on resistance with technology rather than resistance to technology. The study shows how the research participants resist structural forces (teaching tension and dominant culture) by using technology to create safe and responsive learning spaces. As such, this thesis challenges educational technologists to re-think the way they support academics by recommending support strategies that acknowledge both the structural forces in the South African higher education context, as well as the culture of resistance, both of which impact academics’ educational technology choices and practices.
- Full Text:
- Date Issued: 2019
Observational cosmology with imperfect data
- Authors: Bester, Hertzog Landman
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/463 , vital:19961
- Description: We develop a formalism suitable to infer the background geometry of a general spherically symmetric dust universe directly from data on the past lightcone. This direct observational approach makes minimal assumptions about inaccessible parts of the Universe. The non-parametric and Bayesian framework we propose provides a very direct way to test one of the most fundamental underlying assumptions of concordance cosmology viz. the Copernican principle. We present the Copernicus algorithm for this purpose. By applying the algorithm to currently available data, we demonstrate that it is not yet possible to confirm or refute the validity of the Copernican principle within the proposed framework. This is followed by an investigation which aims to determine which future data will best be able to test the Copernican principle. Our results on simulated data suggest that, besides the need to improve the current data, it will be important to identify additional model independent observables for this purpose. The main difficulty with current data is their inability to constrain the value of the cosmological constant. We show how redshift drift data could be used to infer its value with minimal assumptions about the nature of the early Universe. We also discuss some alternative applications of the algorithm.
- Full Text:
- Date Issued: 2016
- Authors: Bester, Hertzog Landman
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/463 , vital:19961
- Description: We develop a formalism suitable to infer the background geometry of a general spherically symmetric dust universe directly from data on the past lightcone. This direct observational approach makes minimal assumptions about inaccessible parts of the Universe. The non-parametric and Bayesian framework we propose provides a very direct way to test one of the most fundamental underlying assumptions of concordance cosmology viz. the Copernican principle. We present the Copernicus algorithm for this purpose. By applying the algorithm to currently available data, we demonstrate that it is not yet possible to confirm or refute the validity of the Copernican principle within the proposed framework. This is followed by an investigation which aims to determine which future data will best be able to test the Copernican principle. Our results on simulated data suggest that, besides the need to improve the current data, it will be important to identify additional model independent observables for this purpose. The main difficulty with current data is their inability to constrain the value of the cosmological constant. We show how redshift drift data could be used to infer its value with minimal assumptions about the nature of the early Universe. We also discuss some alternative applications of the algorithm.
- Full Text:
- Date Issued: 2016
Development of molecularly imprinted polymer based solid phase extraction sorbents for the selective cleanup of food and pharmaceutical residue samples
- Authors: Batlokwa, Bareki Shima
- Date: 2012
- Subjects: Sorbents -- Research Nanofibers -- Research Aflatoxins -- Research Electrospinning -- Research Extraction (Chemistry) -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4309 , http://hdl.handle.net/10962/d1004967
- Description: This thesis presents the development of chlorophyll, cholic acid, aflatoxin B1 molecularly imprinted polymer (MIP) particles and cholic acid MIP nanofibers for application as selective solid phase extraction (SPE) sorbents. The particles were prepared by bulk polymerization and the nanofibers by a novel approach combining molecular imprinting and electrospinning technology. The AFB1 MIP particles were compared with an aflatoxin specific immunoextraction sorbent in cleaning-up and pre-concentrating aflatoxins from nut extracts. They both recorded high extraction efficiencies (EEs) of > 97 % in selectively extracting the aflatoxins (AFB1, AFB2, AFG1 and AFG2). High reproducibility marked by the low %RSDs of < 1% and low LODs of ≤ 0.02 ng/g were calculated in all cases. The LODs were within the monitoring requirements of the European Commission. The results were validated with a peanut butter certified reference material. The chlorophyll MIP on the other hand selectively removed chlorophyll that would otherwise interfere during pesticide residue analysis (PRA) from > 0.6 to <0.09 Au in green plants extracts. The extracted chlorophyll was removed to far below the level of ≥ 0.399 Au that is usually associated with interference during PRA. Furthermore, the MIP demonstrated better selectivity by removing only chlorophyll (> 99%) in the presence of planar pesticides than the currently employed graphitized carbon black (GCB) that removed both the chlorophyll (> 88%) and planar pesticides (> 89%). For the interfering cholic acid during drug residue analysis, cholic acid MIP electrospun nanofibers demonstrated to be more sensitive and possessing higher loading capacity than the MIP particles. 100% cholic acid was removed by the nanofibers from standard solutions relative to 80% by the particles. This showed that the nanofibers have better performance than the micro particles and as such have potential to replace the particle based SPE sorbents that are currently in use. All the templates were optimally removed from the prepared MIPs by employing a novel pressurized hot water extraction template removal method that was used for the first time in this thesis. The method employed only water, an environmentally friendly solvent to remove templates to ≥ 99.6% with template residual bleeding of ≤ 0.02%.
- Full Text:
- Date Issued: 2012
- Authors: Batlokwa, Bareki Shima
- Date: 2012
- Subjects: Sorbents -- Research Nanofibers -- Research Aflatoxins -- Research Electrospinning -- Research Extraction (Chemistry) -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4309 , http://hdl.handle.net/10962/d1004967
- Description: This thesis presents the development of chlorophyll, cholic acid, aflatoxin B1 molecularly imprinted polymer (MIP) particles and cholic acid MIP nanofibers for application as selective solid phase extraction (SPE) sorbents. The particles were prepared by bulk polymerization and the nanofibers by a novel approach combining molecular imprinting and electrospinning technology. The AFB1 MIP particles were compared with an aflatoxin specific immunoextraction sorbent in cleaning-up and pre-concentrating aflatoxins from nut extracts. They both recorded high extraction efficiencies (EEs) of > 97 % in selectively extracting the aflatoxins (AFB1, AFB2, AFG1 and AFG2). High reproducibility marked by the low %RSDs of < 1% and low LODs of ≤ 0.02 ng/g were calculated in all cases. The LODs were within the monitoring requirements of the European Commission. The results were validated with a peanut butter certified reference material. The chlorophyll MIP on the other hand selectively removed chlorophyll that would otherwise interfere during pesticide residue analysis (PRA) from > 0.6 to <0.09 Au in green plants extracts. The extracted chlorophyll was removed to far below the level of ≥ 0.399 Au that is usually associated with interference during PRA. Furthermore, the MIP demonstrated better selectivity by removing only chlorophyll (> 99%) in the presence of planar pesticides than the currently employed graphitized carbon black (GCB) that removed both the chlorophyll (> 88%) and planar pesticides (> 89%). For the interfering cholic acid during drug residue analysis, cholic acid MIP electrospun nanofibers demonstrated to be more sensitive and possessing higher loading capacity than the MIP particles. 100% cholic acid was removed by the nanofibers from standard solutions relative to 80% by the particles. This showed that the nanofibers have better performance than the micro particles and as such have potential to replace the particle based SPE sorbents that are currently in use. All the templates were optimally removed from the prepared MIPs by employing a novel pressurized hot water extraction template removal method that was used for the first time in this thesis. The method employed only water, an environmentally friendly solvent to remove templates to ≥ 99.6% with template residual bleeding of ≤ 0.02%.
- Full Text:
- Date Issued: 2012
Sedimentology of plio-pleistocene gravel barrier deposits in the palaeo-Orange River mouth, Namibia : depositional history and diamond mineralisation
- Authors: Spaggiari, Renato Igino
- Date: 2011 , 2013-08-19
- Subjects: Diamond mines and mining -- Namibia Sediments (Geology) -- South Africa and Namibia -- Orange River Estuary Diamond deposits -- Namibia Orange River Estuary (Namibia and South Africa)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4927 , http://hdl.handle.net/10962/d1004636
- Description: The largest known marine diamond placer, the Namibian mega-placer, lies along the Atlantic coast of south-western Africa from the Orange River mouth 1,000 km northwards to the Namibian-Angolan border. The most economically viable portion of the Namibian mega-placer (>75 million carats recovered at >95% gem quality) comprises onshore and offshore marine deposits that are developed within ∼100km of the Orange River outfall. For much of the Cainozoic, this long-lived fluvial system has been the main conduit transporting diamonds from kimberlitic and secondary sources in the cratonic hinterland of southern Africa to the Atlantic shelf that has been neutrally buoyant over this period. Highly energetic marine processes, driven in part, by southerly winds with an attendant northward-directed longshore drift, have generated terminal placers that are preserved both onshore and offshore. This study, through detailed field sedimentological and diamond analyses, investigates the development and mineralisation of gravel barrier deposits within the ancestral Orange River mouth area during a major ∼30 m regional transgression ('30 m Package') in the Late Pliocene. At that time, diamond supply from this fluvial conduit was minimal, yet the corresponding onshore marine deposits to the north of the Orange River mouth were significantly diamond enriched, enabling large-scale alluvial diamond mining to take place for over 75 years. Of the entire coastline of south-western Africa, the most complete accumulation of the '30 m Package' is preserved within the palaeo-Orange River mouth as barrier spit and barrier beach deposits. Arranged vertically and laterally in a 16m thick succession, these are deposits of: (1) intertidal beach, (2) lagoon and washover, (3) tidal inlet and spit recurve and (4) storm-dominated subtidal settings. These were parts of larger barrier features, the bulk of which are preserved as highstand deposits that are diamond-bearing with varying, but generally low grades (<13 stones (diamonds) per hundred tons, spht). Intertidal beach and spit recurve deposits have higher economic grades (12-13 spht) due to the energetic sieving and mobile trapping mechanisms associated with their emplacement. In contrast, the less reworked and more sandy subtidal, tidal inlet and washover deposits have un-economic grades (<2 spht). Despite these low grades, the barrier deposits have the largest average stone (diamond) size (1-2 carats/stone, cts/stn) of the entire Namibian mega-placer, given their proximity to the ancestral Orange River outfall. This study demonstrates that barrier shoreline evolution at the fluvial/marine interface was controlled by: (1) a strong and coarse fluvial sediment supply that sustained shoreline growth on a highly energetic coast, (2) accommodation space facilitating sediment preservation and (3) short-duration, high-frequency sea-level cycles superimposed on the∼30 m regional transgression, promoting hierarchal stacking of progradational deposits. During these sea-level fluctuations, diamonds were 'farmed' from older, shelf sequences in the offshore and driven landward to accumulate in '30 m Package' highstand barrier deposits. In spite of the large supply of diamonds, their retention in these deposits was poor due to an incompetent footwall of ancestral Orange River mouth sediment and the inherent cobble-boulder size of the barrier gravels. Thus the principal process controlling diamond entrapment in these barrier deposits was kinetic sieving in a coarse-grained framework. Consequently, at the marine/fluvial interface and down-drift for ∼5 km, larger diamonds (1-2 cts/stn) were retained in low-grade (<2 spht), coarse-gravel barrier shorelines. Smaller diamonds (mostly < I cts/stn) were rejected into the northward-driven littoral sediments and further size-sorted along ∼95 km of Namibian coast to accumulate in finer, high-grade beach placers (> 100 spht) where bedrock footwall promoted such high concentrations. The gravel-dominated palaeo-Orange River mouth is considered to be the ' heart' of the Namibian mega-placer, controlling sediment and diamond supply to the littoral zone further north. Although coarse gravel is retained at the river mouth, the incompetence of this highly energetic setting to trap diamonds renders it sub-economic. This ineffectiveness at the fluvial/marine interface is thus fundamental in enriching the coastal tract farther down-drift and developing highly economic coastal placers along the Atlantic coast of south-western Africa. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2011
- Authors: Spaggiari, Renato Igino
- Date: 2011 , 2013-08-19
- Subjects: Diamond mines and mining -- Namibia Sediments (Geology) -- South Africa and Namibia -- Orange River Estuary Diamond deposits -- Namibia Orange River Estuary (Namibia and South Africa)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4927 , http://hdl.handle.net/10962/d1004636
- Description: The largest known marine diamond placer, the Namibian mega-placer, lies along the Atlantic coast of south-western Africa from the Orange River mouth 1,000 km northwards to the Namibian-Angolan border. The most economically viable portion of the Namibian mega-placer (>75 million carats recovered at >95% gem quality) comprises onshore and offshore marine deposits that are developed within ∼100km of the Orange River outfall. For much of the Cainozoic, this long-lived fluvial system has been the main conduit transporting diamonds from kimberlitic and secondary sources in the cratonic hinterland of southern Africa to the Atlantic shelf that has been neutrally buoyant over this period. Highly energetic marine processes, driven in part, by southerly winds with an attendant northward-directed longshore drift, have generated terminal placers that are preserved both onshore and offshore. This study, through detailed field sedimentological and diamond analyses, investigates the development and mineralisation of gravel barrier deposits within the ancestral Orange River mouth area during a major ∼30 m regional transgression ('30 m Package') in the Late Pliocene. At that time, diamond supply from this fluvial conduit was minimal, yet the corresponding onshore marine deposits to the north of the Orange River mouth were significantly diamond enriched, enabling large-scale alluvial diamond mining to take place for over 75 years. Of the entire coastline of south-western Africa, the most complete accumulation of the '30 m Package' is preserved within the palaeo-Orange River mouth as barrier spit and barrier beach deposits. Arranged vertically and laterally in a 16m thick succession, these are deposits of: (1) intertidal beach, (2) lagoon and washover, (3) tidal inlet and spit recurve and (4) storm-dominated subtidal settings. These were parts of larger barrier features, the bulk of which are preserved as highstand deposits that are diamond-bearing with varying, but generally low grades (<13 stones (diamonds) per hundred tons, spht). Intertidal beach and spit recurve deposits have higher economic grades (12-13 spht) due to the energetic sieving and mobile trapping mechanisms associated with their emplacement. In contrast, the less reworked and more sandy subtidal, tidal inlet and washover deposits have un-economic grades (<2 spht). Despite these low grades, the barrier deposits have the largest average stone (diamond) size (1-2 carats/stone, cts/stn) of the entire Namibian mega-placer, given their proximity to the ancestral Orange River outfall. This study demonstrates that barrier shoreline evolution at the fluvial/marine interface was controlled by: (1) a strong and coarse fluvial sediment supply that sustained shoreline growth on a highly energetic coast, (2) accommodation space facilitating sediment preservation and (3) short-duration, high-frequency sea-level cycles superimposed on the∼30 m regional transgression, promoting hierarchal stacking of progradational deposits. During these sea-level fluctuations, diamonds were 'farmed' from older, shelf sequences in the offshore and driven landward to accumulate in '30 m Package' highstand barrier deposits. In spite of the large supply of diamonds, their retention in these deposits was poor due to an incompetent footwall of ancestral Orange River mouth sediment and the inherent cobble-boulder size of the barrier gravels. Thus the principal process controlling diamond entrapment in these barrier deposits was kinetic sieving in a coarse-grained framework. Consequently, at the marine/fluvial interface and down-drift for ∼5 km, larger diamonds (1-2 cts/stn) were retained in low-grade (<2 spht), coarse-gravel barrier shorelines. Smaller diamonds (mostly < I cts/stn) were rejected into the northward-driven littoral sediments and further size-sorted along ∼95 km of Namibian coast to accumulate in finer, high-grade beach placers (> 100 spht) where bedrock footwall promoted such high concentrations. The gravel-dominated palaeo-Orange River mouth is considered to be the ' heart' of the Namibian mega-placer, controlling sediment and diamond supply to the littoral zone further north. Although coarse gravel is retained at the river mouth, the incompetence of this highly energetic setting to trap diamonds renders it sub-economic. This ineffectiveness at the fluvial/marine interface is thus fundamental in enriching the coastal tract farther down-drift and developing highly economic coastal placers along the Atlantic coast of south-western Africa. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2011
Biological control initiatives against Lantana camara L. (Verbenaceae) in South Africa : an assessment of the present status of the programme, and an evaluation of Coelocephalapion camarae Kissinger (Coleoptera: Brentidae) and Falconia intermedia (Distant) (Heteroptera: Miridae), two new candidate natural enemies for release on the weed
- Authors: Baars, Jan-Robert
- Date: 2003
- Subjects: Lantana camara Lantana camera -- South Africa Biological pest control agents -- South Africa Beetles -- South Africa Hemiptera -- South Africa Weeds -- Biological control -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5647 , http://hdl.handle.net/10962/d1005329
- Description: Lantana camara (lantana), a thicket-forming shrub, a number of different varieties of which were introduced into South Africa as ornamental plants but which has become a serious invasive weed. Conventional control measures for lantana are expensive and ineffective and it has therefore been targeted for biological control since 1961. To date, eleven biological control agent species have become established on lantana in South Africa. However, most agents persist at low densities and only occasionally impact plant populations. Three species regularly cause significant damage, but only reach sufficiently high numbers by midsummer after populations crash during the winter. Overall, the impact of the biological control programme on the weed is negligible and this has been ascribed to the poor selection of agents for release, the accumulation of native parasitoids, differences in insect preference for different varieties of the weed and variable climatic conditions over the weed’s range. This study suggests that the importance of varietal preferences has been over-estimated. A predictive bioclimatic modelling technique showed that most of the agents established in South Africa have a wide climatic tolerance and that the redistribution and importation of new climatypes of these agents will not improve the level of control. Additional agents are required to improve the biocontrol in the temperate conditions, and also to increase damage in the sub-tropical areas where most of the agents are established and where the weed retains its leaves year round. New candidate agents that possess biological attributes that favour a high intrinsic rate of increase, a high impact per individual and that improve the synchrony between the weed and the agent in climatic conditions that promote the seasonal leaflessness of plants should receive prior consideration. A survey in Jamaica indicated that additional biological control agents are available in the region of origin but that care should be taken to prioritise the most effective agents. The various selection systems currently available in weed biocontrol produce contradictory results in the priority assigned to candidate agents and a new selection system is proposed. The biology and host range of two new candidate natural enemies, the leaf-galling weevil, Coelocephalapion camarae and the leaf-sucking mirid, Falconia intermedia were investigated for the biocontrol of lantana. The studies indicated that these have considerable biocontrol potential, in that the weevil has a wide climatic tolerance and has the potential to survive the host leaflessness typical of temperate conditions, while the mirid has a high intrinsic rate of increase, and the potential for several generations a year. Both agents caused a high level of damage to the leaves, with the weevil galling the vascular tissue in the leaf-petiole and the mirid causing chlorotic speckling of the leaves. During laboratory trials both agents accepted indigenous species in the genus Lippia. However, under multiple choice conditions these agents showed a significant and strong oviposition preference for lantana. A risk assessment and post release field trials indicated that F. intermedia is likely to attack some Lippia species in the presence of lantana, but the levels of damage are predicted to be relatively low. A possible low incidence of damage to indigenous species was considered a justifiable ‘trade-off’ for the potentially marked impact on L. camara. Preference and performance studies on the two candidate agents suggested that most of the South African lantana varieties are suitable host plants. The mirid preferred certain varieties in multiple choice experiments, but this is unlikely to affect its impact under field conditions. Permission for release was accordingly sought for both species. Finally, the challenges facing the biological control programme and the potential for improving the control of L. camara in South Africa are considered.
- Full Text:
- Date Issued: 2003
- Authors: Baars, Jan-Robert
- Date: 2003
- Subjects: Lantana camara Lantana camera -- South Africa Biological pest control agents -- South Africa Beetles -- South Africa Hemiptera -- South Africa Weeds -- Biological control -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5647 , http://hdl.handle.net/10962/d1005329
- Description: Lantana camara (lantana), a thicket-forming shrub, a number of different varieties of which were introduced into South Africa as ornamental plants but which has become a serious invasive weed. Conventional control measures for lantana are expensive and ineffective and it has therefore been targeted for biological control since 1961. To date, eleven biological control agent species have become established on lantana in South Africa. However, most agents persist at low densities and only occasionally impact plant populations. Three species regularly cause significant damage, but only reach sufficiently high numbers by midsummer after populations crash during the winter. Overall, the impact of the biological control programme on the weed is negligible and this has been ascribed to the poor selection of agents for release, the accumulation of native parasitoids, differences in insect preference for different varieties of the weed and variable climatic conditions over the weed’s range. This study suggests that the importance of varietal preferences has been over-estimated. A predictive bioclimatic modelling technique showed that most of the agents established in South Africa have a wide climatic tolerance and that the redistribution and importation of new climatypes of these agents will not improve the level of control. Additional agents are required to improve the biocontrol in the temperate conditions, and also to increase damage in the sub-tropical areas where most of the agents are established and where the weed retains its leaves year round. New candidate agents that possess biological attributes that favour a high intrinsic rate of increase, a high impact per individual and that improve the synchrony between the weed and the agent in climatic conditions that promote the seasonal leaflessness of plants should receive prior consideration. A survey in Jamaica indicated that additional biological control agents are available in the region of origin but that care should be taken to prioritise the most effective agents. The various selection systems currently available in weed biocontrol produce contradictory results in the priority assigned to candidate agents and a new selection system is proposed. The biology and host range of two new candidate natural enemies, the leaf-galling weevil, Coelocephalapion camarae and the leaf-sucking mirid, Falconia intermedia were investigated for the biocontrol of lantana. The studies indicated that these have considerable biocontrol potential, in that the weevil has a wide climatic tolerance and has the potential to survive the host leaflessness typical of temperate conditions, while the mirid has a high intrinsic rate of increase, and the potential for several generations a year. Both agents caused a high level of damage to the leaves, with the weevil galling the vascular tissue in the leaf-petiole and the mirid causing chlorotic speckling of the leaves. During laboratory trials both agents accepted indigenous species in the genus Lippia. However, under multiple choice conditions these agents showed a significant and strong oviposition preference for lantana. A risk assessment and post release field trials indicated that F. intermedia is likely to attack some Lippia species in the presence of lantana, but the levels of damage are predicted to be relatively low. A possible low incidence of damage to indigenous species was considered a justifiable ‘trade-off’ for the potentially marked impact on L. camara. Preference and performance studies on the two candidate agents suggested that most of the South African lantana varieties are suitable host plants. The mirid preferred certain varieties in multiple choice experiments, but this is unlikely to affect its impact under field conditions. Permission for release was accordingly sought for both species. Finally, the challenges facing the biological control programme and the potential for improving the control of L. camara in South Africa are considered.
- Full Text:
- Date Issued: 2003
Can expansive (social) learning processes strengthen organisational learning for improved wetland management in a plantation forestry company, and if so how? : a case study of Mondi
- Authors: Lindley, David Stewart
- Date: 2014
- Subjects: Mondi Group , Wetland management -- South Africa , Wetland conservation -- Study and teaching (Continuing education) , Employees -- Training of -- South Africa , Action theory , Critical realism , Social learning , Environmental education -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2003 , http://hdl.handle.net/10962/d1015661
- Description: Mondi is an international packaging and paper company that manages over 300 000 ha of land in South Africa. After over a decade of working with Mondi to improve its wetland management, wetland sustainability practices were still not integrated into the broader forestry operations, despite some significant cases of successful wetland rehabilitation. An interventionist research project was therefore conducted to explore the factors inhibiting improved wetland management, and determine if and how expansive social learning processes could strengthen organisational learning and development to overcome these factors. In doing so, the research has investigated how informal adult learning supports organisational change to strengthen wetland and environmental sustainability practices, within a corporate plantation forestry context. How individual and/or group-based learning interactions translate to the collective, at the level of organisational change was a key issue probed in this study. The following three research questions were used to guide the research: 1. What tensions and contradictions exist in wetland management in a plantation forestry company? 2. Can expansive learning begin to address the tensions and contradictions that exist in wetland management in a plantation forestry company, for improved sustainability practices? 3. Can expansive social learning strengthen organisational learning and development, enabling Mondi to improve its wetland sustainability practices, and if so how does it do this? Cultural historical activity theory (CHAT) and the theory of expansive learning provided an epistemological framework for the research. The philosophy of critical realism gave ontological depth to the research, and contributed to a deeper understanding of CHAT and expansive learning. Critical realism was therefore used as a philosophy to underlabour the theoretical framework of the research. However CHAT and expansive learning could not provide the depth of detail required to explain how the expansive learning, organisational social change, and boundary crossings that are necessary for assembling the collective were taking place. Realist social theory (developed out of critical realism by Margaret Archer as an ontologically located theory of how and why social change occurs, or does not) supported the research to do this. The morphogenetic framework was used as a methodology for applying realist social theory. The expansive learning cycle was used as a methodology for applying CHAT and the theory of expansive learning; guiding the development of new knowledge creation required by Mondi staff to identify contradictions and associated tensions inhibiting wetland management, understand their root causes, and develop solutions. Through the expansive learning process, the tensions and contradictions become generative as a tool supporting expansive social learning, rather than as a means to an end where universal consensus was reached on how to circumvent the contradictions. The research was conducted in five phases: • Phase 1: Contextual profiling to identify and describe three activity systems in Mondi responsible for wetland management: 1) siviculture foresters; 2) environmental specialists; 3) community engagement facilitators. The data was generated and analysed through through document analysis, 17 interviews, 2nd generation CHAT analysis, and Critical Realist generative mechanism analysis; • Phase 2: Analysis and identification of tensions and contradictions through a first interventionist workshop. Modelling new solutions to deal with contractions, and examining and testing new models in and after the second interventionist workshop; • Phase 3: Implementing new models as wetland management projects and involved project implementation. This included boundary crossing practices of staff in the three activity systems, reflection and re-view in a further five progress review/interventionist workshops, and a management meeting and seminar; • Phase 4: Reflecting on the expansive learning process, results, and consolidation of changed practices, through nine reflective interviews and field observations; • Phase 5: Morphogenic/stasis analysis of the organisational change and development catalysed via the expansive social learning process (or not). The research found that expansive social learning processes supported organisational learning and development for improved wetland management by: 1) strengthening the scope, depth, and sophistication of participant understanding; 2) expanding the ways staff interact and collaboratively work together; 3) democratising decision making; 4) improving social relations between staff, reducing power differentials, and creating stronger relationships; 5) enhancing participant reflexivity through deeper understanding of social structures and cultural systems, and changing them to support improved wetland and environmental practice of staff, and developing the organisational structures and processes to strengthen organisational learning and development; and 6) using the contradictions identified as generative mechanisms to stimulate and catalyse organisational learning and development for changed wetland/environmental management.
- Full Text:
- Date Issued: 2014
- Authors: Lindley, David Stewart
- Date: 2014
- Subjects: Mondi Group , Wetland management -- South Africa , Wetland conservation -- Study and teaching (Continuing education) , Employees -- Training of -- South Africa , Action theory , Critical realism , Social learning , Environmental education -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2003 , http://hdl.handle.net/10962/d1015661
- Description: Mondi is an international packaging and paper company that manages over 300 000 ha of land in South Africa. After over a decade of working with Mondi to improve its wetland management, wetland sustainability practices were still not integrated into the broader forestry operations, despite some significant cases of successful wetland rehabilitation. An interventionist research project was therefore conducted to explore the factors inhibiting improved wetland management, and determine if and how expansive social learning processes could strengthen organisational learning and development to overcome these factors. In doing so, the research has investigated how informal adult learning supports organisational change to strengthen wetland and environmental sustainability practices, within a corporate plantation forestry context. How individual and/or group-based learning interactions translate to the collective, at the level of organisational change was a key issue probed in this study. The following three research questions were used to guide the research: 1. What tensions and contradictions exist in wetland management in a plantation forestry company? 2. Can expansive learning begin to address the tensions and contradictions that exist in wetland management in a plantation forestry company, for improved sustainability practices? 3. Can expansive social learning strengthen organisational learning and development, enabling Mondi to improve its wetland sustainability practices, and if so how does it do this? Cultural historical activity theory (CHAT) and the theory of expansive learning provided an epistemological framework for the research. The philosophy of critical realism gave ontological depth to the research, and contributed to a deeper understanding of CHAT and expansive learning. Critical realism was therefore used as a philosophy to underlabour the theoretical framework of the research. However CHAT and expansive learning could not provide the depth of detail required to explain how the expansive learning, organisational social change, and boundary crossings that are necessary for assembling the collective were taking place. Realist social theory (developed out of critical realism by Margaret Archer as an ontologically located theory of how and why social change occurs, or does not) supported the research to do this. The morphogenetic framework was used as a methodology for applying realist social theory. The expansive learning cycle was used as a methodology for applying CHAT and the theory of expansive learning; guiding the development of new knowledge creation required by Mondi staff to identify contradictions and associated tensions inhibiting wetland management, understand their root causes, and develop solutions. Through the expansive learning process, the tensions and contradictions become generative as a tool supporting expansive social learning, rather than as a means to an end where universal consensus was reached on how to circumvent the contradictions. The research was conducted in five phases: • Phase 1: Contextual profiling to identify and describe three activity systems in Mondi responsible for wetland management: 1) siviculture foresters; 2) environmental specialists; 3) community engagement facilitators. The data was generated and analysed through through document analysis, 17 interviews, 2nd generation CHAT analysis, and Critical Realist generative mechanism analysis; • Phase 2: Analysis and identification of tensions and contradictions through a first interventionist workshop. Modelling new solutions to deal with contractions, and examining and testing new models in and after the second interventionist workshop; • Phase 3: Implementing new models as wetland management projects and involved project implementation. This included boundary crossing practices of staff in the three activity systems, reflection and re-view in a further five progress review/interventionist workshops, and a management meeting and seminar; • Phase 4: Reflecting on the expansive learning process, results, and consolidation of changed practices, through nine reflective interviews and field observations; • Phase 5: Morphogenic/stasis analysis of the organisational change and development catalysed via the expansive social learning process (or not). The research found that expansive social learning processes supported organisational learning and development for improved wetland management by: 1) strengthening the scope, depth, and sophistication of participant understanding; 2) expanding the ways staff interact and collaboratively work together; 3) democratising decision making; 4) improving social relations between staff, reducing power differentials, and creating stronger relationships; 5) enhancing participant reflexivity through deeper understanding of social structures and cultural systems, and changing them to support improved wetland and environmental practice of staff, and developing the organisational structures and processes to strengthen organisational learning and development; and 6) using the contradictions identified as generative mechanisms to stimulate and catalyse organisational learning and development for changed wetland/environmental management.
- Full Text:
- Date Issued: 2014
Establishing a formulation design space for a generic clobetasol 17- propionate cream using the principles of quality by design
- Fauzee, Ayeshah Fateemah Beebee
- Authors: Fauzee, Ayeshah Fateemah Beebee
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:20983 , http://hdl.handle.net/10962/5868
- Description: The pharmaceutical industry is global, is highly regulated and is able to achieve reasonable product quality but at high cost with maximum effort. Numerous challenges face the pharmaceutical industry and include a shrinking research pipeline, less innovation, outsourcing, investments, increasing research and development costs, long approval times, growth of the generic industry, failure to understand or analyze manufacturing failure and wastage as high at fifty percent for some pharmaceutical products. An efficient and flexible pharmaceutical sector should be able to consistently produce high quality pharmaceutical products at a reduced cost with minimal waste. As a result, Food and Drug Administration (FDA) and other agencies such as the International Conference on Harmonization (ICH) have embraced a “Quality by Design” (QbD) paradigm and this has become the “desired state” so as to shift manufacturing from being empirical to a science, engineering, and risk based approach. QbD is a systematic approach for the development of high quality pharmaceutical dosage forms that begins with predefined objectives based on the premise that quality must be built into and not tested into a product. QbD together with the establishment of a design space for dosage forms is a fairly new concept and there is limited published data on QbD concepts that report the entire process of identifying Critical Quality Attributes (CQA), design of a formulation and manufacturing process to meet product CQA, understanding the impact of material attributes and process parameters on product CQA, identification and controlling sources of variability in materials and processes that affect the CQA of a product and finally establishing, evaluating and testing a design space using both in vitro and in vivo approaches to assure that a product of consistent quality can always be produced. The objective of these studies was to implement a QbD approach to establish a design space for the development and manufacture of a safe, effective, stable generic formulation containing 0.05% w/w clobetasol 17-propionate (CP) that had similar in vitro and in vivo characteristics to an innovator product, Dermovate® (Sekpharma® Pty Ltd, Sandton, Gauteng, RSA). Such a product would pose a minimal risk of failure when treating severe skin disorders such as seborrhoeic dermatitis, extreme photodermatitis and/or severe psoriasis in HIV/AIDS patients in Southern Africa.
- Full Text:
- Date Issued: 2014
- Authors: Fauzee, Ayeshah Fateemah Beebee
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:20983 , http://hdl.handle.net/10962/5868
- Description: The pharmaceutical industry is global, is highly regulated and is able to achieve reasonable product quality but at high cost with maximum effort. Numerous challenges face the pharmaceutical industry and include a shrinking research pipeline, less innovation, outsourcing, investments, increasing research and development costs, long approval times, growth of the generic industry, failure to understand or analyze manufacturing failure and wastage as high at fifty percent for some pharmaceutical products. An efficient and flexible pharmaceutical sector should be able to consistently produce high quality pharmaceutical products at a reduced cost with minimal waste. As a result, Food and Drug Administration (FDA) and other agencies such as the International Conference on Harmonization (ICH) have embraced a “Quality by Design” (QbD) paradigm and this has become the “desired state” so as to shift manufacturing from being empirical to a science, engineering, and risk based approach. QbD is a systematic approach for the development of high quality pharmaceutical dosage forms that begins with predefined objectives based on the premise that quality must be built into and not tested into a product. QbD together with the establishment of a design space for dosage forms is a fairly new concept and there is limited published data on QbD concepts that report the entire process of identifying Critical Quality Attributes (CQA), design of a formulation and manufacturing process to meet product CQA, understanding the impact of material attributes and process parameters on product CQA, identification and controlling sources of variability in materials and processes that affect the CQA of a product and finally establishing, evaluating and testing a design space using both in vitro and in vivo approaches to assure that a product of consistent quality can always be produced. The objective of these studies was to implement a QbD approach to establish a design space for the development and manufacture of a safe, effective, stable generic formulation containing 0.05% w/w clobetasol 17-propionate (CP) that had similar in vitro and in vivo characteristics to an innovator product, Dermovate® (Sekpharma® Pty Ltd, Sandton, Gauteng, RSA). Such a product would pose a minimal risk of failure when treating severe skin disorders such as seborrhoeic dermatitis, extreme photodermatitis and/or severe psoriasis in HIV/AIDS patients in Southern Africa.
- Full Text:
- Date Issued: 2014
Torn between skinship and kinship: the phenomenology of self-mutilation
- Authors: Malcolm, Charles F
- Date: 1994
- Subjects: Self-mutilation Case studies Borderline personality disorder
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3012 , http://hdl.handle.net/10962/d1002521
- Description: The aim of this study was to describe the female elf-mutilator's lived experience of cutting herself. A question which would elicit a description of the experience of this phenomenon was formulated. Five self-mutilators were interviewed. The four psychologically richest narratives were chosen for this study. Using the empirical phenomenological method. the four protocols were analysed in detail. Self-mutilation is conceptualized as a cycle wherein the mutilator experiences a diffuse bodily felt-sense that mounts to an unbearable point. She has an irresistible urge to alleviate the distress. She isolates herself and cuts herself with a sharp blade. Upon seeing the blood appear she is overcome with a deep sense of satisfaction. power, and ecstatic pleasure. The blood is perceived to carry the distressing contents out of the body. Concomitantly the self-mutilator recollects a sense of her feelings and her body as belonging to her. Her previously alienated body is felt to be a site of vitality. She also feels removed from further harm. encased in a cocoon of safety that renders her invulnerable to others. However. the cutting can never totally rid the body of distressing feelings. As a result the cycle of cutting wiII be re-enacted. The cutting cycle is conceptualized as a process whereby the self-mutilator suffers from a traumatization of the psyche such that the psychic container is fractured and rendered painfully porous. The act of cutting rids the psyche of unwanted contents such that a sense of going-on-being is restored. The cutting acts to temporarily shore up the rent fabric of the psychic envelope and thereby consolidate a sense of personal boundary. This is a temporary respite from the fracturing of the psychic container in that, once again confronted with interpersonal existence, the self-mutilator begins to feel vulnerable and defenceless. When it seems as if disintegration is again imminent, a cycle of cutting is reconstituted. The findings emergent from the interviews were dialogued with the literature on psychic containers, particularly that which addresses the role of the skin in the formation and functioning of psychic containers.
- Full Text:
- Date Issued: 1994
- Authors: Malcolm, Charles F
- Date: 1994
- Subjects: Self-mutilation Case studies Borderline personality disorder
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3012 , http://hdl.handle.net/10962/d1002521
- Description: The aim of this study was to describe the female elf-mutilator's lived experience of cutting herself. A question which would elicit a description of the experience of this phenomenon was formulated. Five self-mutilators were interviewed. The four psychologically richest narratives were chosen for this study. Using the empirical phenomenological method. the four protocols were analysed in detail. Self-mutilation is conceptualized as a cycle wherein the mutilator experiences a diffuse bodily felt-sense that mounts to an unbearable point. She has an irresistible urge to alleviate the distress. She isolates herself and cuts herself with a sharp blade. Upon seeing the blood appear she is overcome with a deep sense of satisfaction. power, and ecstatic pleasure. The blood is perceived to carry the distressing contents out of the body. Concomitantly the self-mutilator recollects a sense of her feelings and her body as belonging to her. Her previously alienated body is felt to be a site of vitality. She also feels removed from further harm. encased in a cocoon of safety that renders her invulnerable to others. However. the cutting can never totally rid the body of distressing feelings. As a result the cycle of cutting wiII be re-enacted. The cutting cycle is conceptualized as a process whereby the self-mutilator suffers from a traumatization of the psyche such that the psychic container is fractured and rendered painfully porous. The act of cutting rids the psyche of unwanted contents such that a sense of going-on-being is restored. The cutting acts to temporarily shore up the rent fabric of the psychic envelope and thereby consolidate a sense of personal boundary. This is a temporary respite from the fracturing of the psychic container in that, once again confronted with interpersonal existence, the self-mutilator begins to feel vulnerable and defenceless. When it seems as if disintegration is again imminent, a cycle of cutting is reconstituted. The findings emergent from the interviews were dialogued with the literature on psychic containers, particularly that which addresses the role of the skin in the formation and functioning of psychic containers.
- Full Text:
- Date Issued: 1994
Transcription, edition, translation and critical analysis of biographical poems contributed by S E K Mqhayi to early IsiXhosa newspapers
- Authors: Mazwi, Ntombomzi R
- Date: 2017
- Subjects: Mqhayi, S E K -- Criticism and interpretation , Mqhayi, S E K -- Translations , Xhosa language -- Transcription , Xhosa poetry -- History and criticism , Xhosa poetry -- Translations
- Language: English , Xhosa
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/18570 , vital:22356
- Description: During the nineteenth century secular creative literature produced by missionaries and publishers was designed for the educational market and for school children and there was nothing for adults. Works of isiXhosa literature was controlled in content and freely edited by the missionaries to satisfy the demands of educational syllabuses. As a result, students at universities, scholars of literature and academics in higher education are lacking primary documents on this literature and therefore are forced to study the limited and unavailable literature books. This thesis concentrates on the work of a particular isiXhosa writer, namely that of S.E.K. Mqhayi. The earlier writers like S.E.K. Mqhayi, J.J.R. Jolobe, G.B. Sinxo and others made their mark in South African literature and culture. Their works were published in journals and newspapers in isiXhosa by the missionaries. This means isiXhosa literature can be found in abundance in the earlier newspapers. What needs to be addressed is how the South African community and literature scholars mentioned above could have access to that work. Mqhayi is well known as the father of the isiXhosa language because of his substantial literary and linguistic contribution to the development of the language. As already mentioned he made his contribution through written work which was published in various newspapers of his time and unfortunately most people are unable to access this material, hence the focus of this thesis. The vast majority of his journalism remains as yet uncollected. However, scholars like Opland (1983) and Saule (1989) made some effort to bring this information to the public through their extensive research. S.E.K. Mqhayi’s popular poems have been published and analyzed over the last century and more recently (Qangule 1979; Kuse 1979; Opland 1983; Saule 1989 & 1996; Ntuli & Swanepoel 1993 and Opland 2009). However, in terms of quantity and value, these are negligible compared to what Mqhayi has published. There are still numerous of Mqhayi’s poems that would add value to the study and history of isiXhosa literature. The main aim of this research is to carry on from where these scholars left off and to bring to the fore the legacy Mqhayi left to the South African people. Hence, thirty (30) poems on people by S.E.K. Mqhayi have been transcribed from the old newspapers, re- typed, translated into English and analysed. These poems are largely published in newspapers but have never been subsequently republished, and hence they are almost completely unknown. The thirty (30) poems have been selected with the assistance of Professor Jeff Opland, a retired Professor from the University of London’s School of Oriental and African Studies (SOAS). The poems are from his Opland Collection of Xhosa Literature housed in Godalming, United Kingdom. They are presented in the manner in which they appeared originally, that is, in terms of isiXhosa orthography during the times of Mqhayi’s writing (Diplomatic Presentation). The data is analysed and discussed in relation to how Mqhayi’s biographical poems can give insight not only to Mqhayi’s subjects of praise, but into how he uses historical, political and sociocultural contexts in the praises of his subjects, meaning that the discussion revolves around the practice of the Historical-Biographical Criticism. The poems are translated into English to allow for this literature not only to be disseminated among isiXhosa speakers, but also to speakers of other languages who understand English. The translation method chosen is the one believed to produce the originality of the source text and sameness of meaning in the target text which is regarded as equivalence. This thesis therefore is an investigation into 30 poems selected from biographical poems written by S.E.K. Mqhayi in newspapers during the period 1899-1944. In essence this thesis presents an in-depth analysis of Mqhayi’s poems against the backdrop of oral literary theory as expounded by theorists who have grappled with the orality-literacy debate, a debate which directly informs Mqhayi’s poetry as he was the first oral poet to transition between orality and literacy. , Uncwadi oluveliswe kwishumi elinesithoba lamakhulu eminyaka ziimishinari nabapapashi lwalwenzelwe izifundiswa kunye nabantwana besikolo kwaye akukho msebenzi mninzi ofumanekayo owawenzelwe abantu basekuhlaleni. Umsebenzi omninzi wokubhaliweyo kuncwadi lwesiXhosa wawulawulwa, uhlelwa kwaye ulungiselelwa uqingqo lwezifundo. Oko ke kuye kwabangela ukuba abafundi abakumaziko emfundo ephakamileyo, iimfundi zoncwadi kunye nabahlohli zingabinawo amaxwebhu okwenene oncwadi lwesiXhosa, kwaye loo nto yenza ukuba kufundwe kwaye kwenziwe uphando ngeencwadi ezimbalwa. Olu phando ke ngoko luza kuqwalasela lugxininise kumsebenzi wombhali wesiXhosa onguS.E.K. Mqhayi. Ababhali bangaphambili abafana noo-S.E.K. Mqhayi, J.J.R. Jolobe, G.B. Sinxo nabanye bashiya ifuthe elikhulu kuncwadi nenkcubeko yoMzantsi Afrika. Imisebenzi yabo yayipapashwe ziimishinari ngesiXhosa kuluhlu lwemibhalo namaphephandaba. Oko ke kuthetha ukuthi le misebenzi yesiXhosa iyafumaneka kumaphepha-ndaba angaphambili. Okufuneka kulungisiwe yindlela abemi boMzantsi Afrika kunye nezi mfundi zoncwadi zikhankanywe ngentla zingathi ziwufumane lo msebenzi waba babhali bangaphambili. UMqhayi waziwa ngokuba yinkcuba- buchopho yolwimi lwesiXhosa kwaye udlale indima enkulu kakhulu ekuphuhliseni ulwimi lwesiXhosa. Njengokuba sele ikhankanyiwe ngentla, umsebenzi wakhe upapashwe kumaphephandaba awohlukeneyo wela xesha wayesaphila kwaye kungelishwa ke ukuba abantu abaninzi abakwazi ukuwufumana loo msebenzi. Eminye yemisebenzi yakhe emininzi ke kodwa ayiqokelelwanga. Iingcali ezifana noo-Opland (1983) noSaule (1989) zaye zenza uphando olukhulu zizama ukuzisa olu lwazi eluntwini, kodwa oko akwanelanga. Kwiminyaka edlulileyo imibongo edumileyo ka-S.E.K. Mqhayi sele yapapashwa (Qangule, 1979; Kuse, 1979; Opland, 1983 & 2009; Saule, 1989 & 1996; Ntuli & Swanepoel, 1993). Nangona kunjalo ke isekhona eminye imibongo kaMqhayi engekaveli nenokuthi ibe nenxaxheba kakhulu ekufundeni nasekufundiseni uncwadi lwesiXhosa. Olu phando ke kukuqhubeka apho aba babhali bakhankanyiweyo bayeke khona ukuzisa phambili umsebenzi nelifa elashiywa nguMqhayi kubemi baseMzantsi Afrika. Kungoko ke imibongo engabantu engama-30 kaMqhayi iza kuthi ikhutshelwe isuka kumaphephandaba akudala, iguqulelwe esiNgesini ze ihlahlelwe. Uninzi lwale mibongo ipapashwe kumaphephandaba akudala kwaye zange iphinde ipapashwe kwenye indawo, kungoko ke ingaziwa kakhulu. Ukukhethwa kwale mibongo ingama-30 kuncediswe nguNjingalwazi uJeff Opland, uNjingalwazi odla umhlala-phantsi weYunivesithi yase-London kwiSikolo seZifundo ngezaseAfrika naseMpumalanga (SOAS). Le mibongo isuka kuluhlu lwakhe athe waluqokelela nolubizwa ngokuba yi-Opland Collection of Xhosa Literature oluse- Godalming, e-United Kingdom. Indlela le mibongo eza kuthi ibhalwe ngayo yileyo uMqhayi wayeyibhale ngayo ngexesha lakhe. Le mibongo ihleliwe kwaye oko kubhaliweyo malunga nayo kuquka indlela apho imibongo kaMqhayi ngobomi babantu kuthi kubonise indlela abonga nabonisa ngayo izinto zoPolitiko, zakudala nezasekuhlaleni ezazisenzeka ngela xesha. Indlela ethi konke oku kuthi kuvele kule mibongo kaMqhayi kwaye kuya kuthi kuvezwe kolu phando. Ukuguqulelwa kwale mibongo esiNgesini kuya kuthi kuncede ukuba nabo bangasithethiyo isiXhosa bakwazi ukufumana le mibongo. Indlela esetyenzisiweyo yoguqulo-lwimi yale mibongo yileyo ivumela ukuba umbhalo uguqulelwe ngokufanayo nombhalo-ntsusa kwaye intsingiselo kumbhalo ekuguqulelwa kuwo ingatshintshi. Lo misebenzi ke ngoko uluphando lwemibongo engabantu ekhethiweyo engama30 ebhalwe nguSEK Mqhayi kumaphephandaba kwimiminyaka u1899 - 1944. Umongo wolu phando kukwenza uhlalutyo - nzulu lwemibongo kaMqhayi eyaleka kuphando - lwazi osele lwenziwe njengoko lucaciswa ziingcali ezithe zazamana nengxoxo yoncwadi lomlomo, ngxoxo leyo ethe yachaphazela ngokumandla umongo wezibongo zikaMqhayi njengembongi yokuqala ukuwela ukusuka kuncwadi lomlomo ukuya kuncwadi olubhaliweyo.
- Full Text:
- Date Issued: 2017
- Authors: Mazwi, Ntombomzi R
- Date: 2017
- Subjects: Mqhayi, S E K -- Criticism and interpretation , Mqhayi, S E K -- Translations , Xhosa language -- Transcription , Xhosa poetry -- History and criticism , Xhosa poetry -- Translations
- Language: English , Xhosa
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/18570 , vital:22356
- Description: During the nineteenth century secular creative literature produced by missionaries and publishers was designed for the educational market and for school children and there was nothing for adults. Works of isiXhosa literature was controlled in content and freely edited by the missionaries to satisfy the demands of educational syllabuses. As a result, students at universities, scholars of literature and academics in higher education are lacking primary documents on this literature and therefore are forced to study the limited and unavailable literature books. This thesis concentrates on the work of a particular isiXhosa writer, namely that of S.E.K. Mqhayi. The earlier writers like S.E.K. Mqhayi, J.J.R. Jolobe, G.B. Sinxo and others made their mark in South African literature and culture. Their works were published in journals and newspapers in isiXhosa by the missionaries. This means isiXhosa literature can be found in abundance in the earlier newspapers. What needs to be addressed is how the South African community and literature scholars mentioned above could have access to that work. Mqhayi is well known as the father of the isiXhosa language because of his substantial literary and linguistic contribution to the development of the language. As already mentioned he made his contribution through written work which was published in various newspapers of his time and unfortunately most people are unable to access this material, hence the focus of this thesis. The vast majority of his journalism remains as yet uncollected. However, scholars like Opland (1983) and Saule (1989) made some effort to bring this information to the public through their extensive research. S.E.K. Mqhayi’s popular poems have been published and analyzed over the last century and more recently (Qangule 1979; Kuse 1979; Opland 1983; Saule 1989 & 1996; Ntuli & Swanepoel 1993 and Opland 2009). However, in terms of quantity and value, these are negligible compared to what Mqhayi has published. There are still numerous of Mqhayi’s poems that would add value to the study and history of isiXhosa literature. The main aim of this research is to carry on from where these scholars left off and to bring to the fore the legacy Mqhayi left to the South African people. Hence, thirty (30) poems on people by S.E.K. Mqhayi have been transcribed from the old newspapers, re- typed, translated into English and analysed. These poems are largely published in newspapers but have never been subsequently republished, and hence they are almost completely unknown. The thirty (30) poems have been selected with the assistance of Professor Jeff Opland, a retired Professor from the University of London’s School of Oriental and African Studies (SOAS). The poems are from his Opland Collection of Xhosa Literature housed in Godalming, United Kingdom. They are presented in the manner in which they appeared originally, that is, in terms of isiXhosa orthography during the times of Mqhayi’s writing (Diplomatic Presentation). The data is analysed and discussed in relation to how Mqhayi’s biographical poems can give insight not only to Mqhayi’s subjects of praise, but into how he uses historical, political and sociocultural contexts in the praises of his subjects, meaning that the discussion revolves around the practice of the Historical-Biographical Criticism. The poems are translated into English to allow for this literature not only to be disseminated among isiXhosa speakers, but also to speakers of other languages who understand English. The translation method chosen is the one believed to produce the originality of the source text and sameness of meaning in the target text which is regarded as equivalence. This thesis therefore is an investigation into 30 poems selected from biographical poems written by S.E.K. Mqhayi in newspapers during the period 1899-1944. In essence this thesis presents an in-depth analysis of Mqhayi’s poems against the backdrop of oral literary theory as expounded by theorists who have grappled with the orality-literacy debate, a debate which directly informs Mqhayi’s poetry as he was the first oral poet to transition between orality and literacy. , Uncwadi oluveliswe kwishumi elinesithoba lamakhulu eminyaka ziimishinari nabapapashi lwalwenzelwe izifundiswa kunye nabantwana besikolo kwaye akukho msebenzi mninzi ofumanekayo owawenzelwe abantu basekuhlaleni. Umsebenzi omninzi wokubhaliweyo kuncwadi lwesiXhosa wawulawulwa, uhlelwa kwaye ulungiselelwa uqingqo lwezifundo. Oko ke kuye kwabangela ukuba abafundi abakumaziko emfundo ephakamileyo, iimfundi zoncwadi kunye nabahlohli zingabinawo amaxwebhu okwenene oncwadi lwesiXhosa, kwaye loo nto yenza ukuba kufundwe kwaye kwenziwe uphando ngeencwadi ezimbalwa. Olu phando ke ngoko luza kuqwalasela lugxininise kumsebenzi wombhali wesiXhosa onguS.E.K. Mqhayi. Ababhali bangaphambili abafana noo-S.E.K. Mqhayi, J.J.R. Jolobe, G.B. Sinxo nabanye bashiya ifuthe elikhulu kuncwadi nenkcubeko yoMzantsi Afrika. Imisebenzi yabo yayipapashwe ziimishinari ngesiXhosa kuluhlu lwemibhalo namaphephandaba. Oko ke kuthetha ukuthi le misebenzi yesiXhosa iyafumaneka kumaphepha-ndaba angaphambili. Okufuneka kulungisiwe yindlela abemi boMzantsi Afrika kunye nezi mfundi zoncwadi zikhankanywe ngentla zingathi ziwufumane lo msebenzi waba babhali bangaphambili. UMqhayi waziwa ngokuba yinkcuba- buchopho yolwimi lwesiXhosa kwaye udlale indima enkulu kakhulu ekuphuhliseni ulwimi lwesiXhosa. Njengokuba sele ikhankanyiwe ngentla, umsebenzi wakhe upapashwe kumaphephandaba awohlukeneyo wela xesha wayesaphila kwaye kungelishwa ke ukuba abantu abaninzi abakwazi ukuwufumana loo msebenzi. Eminye yemisebenzi yakhe emininzi ke kodwa ayiqokelelwanga. Iingcali ezifana noo-Opland (1983) noSaule (1989) zaye zenza uphando olukhulu zizama ukuzisa olu lwazi eluntwini, kodwa oko akwanelanga. Kwiminyaka edlulileyo imibongo edumileyo ka-S.E.K. Mqhayi sele yapapashwa (Qangule, 1979; Kuse, 1979; Opland, 1983 & 2009; Saule, 1989 & 1996; Ntuli & Swanepoel, 1993). Nangona kunjalo ke isekhona eminye imibongo kaMqhayi engekaveli nenokuthi ibe nenxaxheba kakhulu ekufundeni nasekufundiseni uncwadi lwesiXhosa. Olu phando ke kukuqhubeka apho aba babhali bakhankanyiweyo bayeke khona ukuzisa phambili umsebenzi nelifa elashiywa nguMqhayi kubemi baseMzantsi Afrika. Kungoko ke imibongo engabantu engama-30 kaMqhayi iza kuthi ikhutshelwe isuka kumaphephandaba akudala, iguqulelwe esiNgesini ze ihlahlelwe. Uninzi lwale mibongo ipapashwe kumaphephandaba akudala kwaye zange iphinde ipapashwe kwenye indawo, kungoko ke ingaziwa kakhulu. Ukukhethwa kwale mibongo ingama-30 kuncediswe nguNjingalwazi uJeff Opland, uNjingalwazi odla umhlala-phantsi weYunivesithi yase-London kwiSikolo seZifundo ngezaseAfrika naseMpumalanga (SOAS). Le mibongo isuka kuluhlu lwakhe athe waluqokelela nolubizwa ngokuba yi-Opland Collection of Xhosa Literature oluse- Godalming, e-United Kingdom. Indlela le mibongo eza kuthi ibhalwe ngayo yileyo uMqhayi wayeyibhale ngayo ngexesha lakhe. Le mibongo ihleliwe kwaye oko kubhaliweyo malunga nayo kuquka indlela apho imibongo kaMqhayi ngobomi babantu kuthi kubonise indlela abonga nabonisa ngayo izinto zoPolitiko, zakudala nezasekuhlaleni ezazisenzeka ngela xesha. Indlela ethi konke oku kuthi kuvele kule mibongo kaMqhayi kwaye kuya kuthi kuvezwe kolu phando. Ukuguqulelwa kwale mibongo esiNgesini kuya kuthi kuncede ukuba nabo bangasithethiyo isiXhosa bakwazi ukufumana le mibongo. Indlela esetyenzisiweyo yoguqulo-lwimi yale mibongo yileyo ivumela ukuba umbhalo uguqulelwe ngokufanayo nombhalo-ntsusa kwaye intsingiselo kumbhalo ekuguqulelwa kuwo ingatshintshi. Lo misebenzi ke ngoko uluphando lwemibongo engabantu ekhethiweyo engama30 ebhalwe nguSEK Mqhayi kumaphephandaba kwimiminyaka u1899 - 1944. Umongo wolu phando kukwenza uhlalutyo - nzulu lwemibongo kaMqhayi eyaleka kuphando - lwazi osele lwenziwe njengoko lucaciswa ziingcali ezithe zazamana nengxoxo yoncwadi lomlomo, ngxoxo leyo ethe yachaphazela ngokumandla umongo wezibongo zikaMqhayi njengembongi yokuqala ukuwela ukusuka kuncwadi lomlomo ukuya kuncwadi olubhaliweyo.
- Full Text:
- Date Issued: 2017
Using a multi-method approach to understand the movement patterns and the associated environmental correlates of an iconic West African recreational fish
- Authors: Winkler, Alexander Claus
- Date: 2019
- Subjects: Carangidae fishing , Carangidae -- Migration , Carangidae -- Namibia , Carangidae -- Angola , Fish tagging , Carangidae -- Benguela Current , Underwater acoustic telemetry , Ocean temperature -- Physiological effect , Fishes -- Effect of temperature on
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76530 , vital:30597
- Description: The leerfish (Lichia amia), is a large, primarily coastal recreational fish species with a distribution extending from Portugal down the west coast of African to southern Mozambique. Owing to its large size (30 kg), strong fighting abilities and habit of taking surface artificial lures, this species has taken on an iconic stature among shore-based recreational anglers. Its reputation has made it an important angling tourism species that makes an important contribution to the economy of developing countries. For example, the species brought US$243 per harvested kilogramme into the local southern Angola economy. Despite its high value, little is known about its movement patterns in the northern Benguela coastal region, a region which includes southern Angola and northern Namibia. While much is known about the migratory patterns of the South African stock of L. amia, recent molecular studies have shown that the northern Benguela stock of L. amia has been isolated from the South African population for at least two million years, a consequence of the development of the cold Lüderitz upwelling cell in southern Namibia. Although the global population of L. amia is considered a single species, prominent biogeographic barriers within its distribution and subtle morphological differences between specimens captured within its tropical versus warm-temperate distribution suggest otherwise. A multi-method approach incorporating passive acoustic telemetry (PAT), recreational catch-per-unit-effort (CPUE) and conventional tagging (CT) in southern Angola, as well as recreational fisher-ecological knowledge (FEK) from Namibia, was used to investigate the large-scale movement patterns of L. amia within the northern Benguela coastal region. While each method had its own associated limitations, the combination provided a holistic picture of the population's seasonal migratory patterns. Furthermore, PAT successfully identified partial migration with 25% vs 75% of monitored fish exhibiting resident (movements < 100 km) or migratory (movements > 100 km) behaviour, respectively. Further behavioural diversity was observed with ‘resident’, ‘roaming’ and ‘embayment’ contingents identified based on varying levels of affinity to certain habitats. The presence of both resident and migratory individuals within the northernmost study during June and July, combined with available biological information, suggested that area-specific spawning may take place. While PAT, CPUE and CT largely aligned in determining area specific high-area use, results from network analyses and mixed effects models conducted on the PAT data supported the spawning hypothesis, with anomalous behaviour around specific receivers during the spawning season. All fish, regardless of behavioural contingent, displayed similar movement behaviour during the spawning season and this was driven by factors generally associated with reproduction, such as lunar illumination. Interestingly, these drivers were different from those that determined the area specific use of individuals outside of the spawning season. The environmental drivers of longshore migration into the northern study site were identified as a decline in water temperature and shorter day lengths. The results of this study highlight the importance of using a multi-method approach in determining migratory movement behaviour, area specific area use, and stock structure of key fisheries species. The identification of different behavioural contingents highlights the importance of acknowledging individual variation in movement and habitat-use patterns. This is particularly relevant as future climate change and spatiotemporal variation in fishing effort may artificially skew natural selection processes to favour certain behavioural groups. This study also highlighted the importance of scientists forming relationships with resource-users, such as recreational angling lodges in areas where limited research has been conducted. This is particularly relevant within the West African context where little is known about many of the fish species that are being increasingly targeted by tourism angling ventures.
- Full Text:
- Date Issued: 2019
- Authors: Winkler, Alexander Claus
- Date: 2019
- Subjects: Carangidae fishing , Carangidae -- Migration , Carangidae -- Namibia , Carangidae -- Angola , Fish tagging , Carangidae -- Benguela Current , Underwater acoustic telemetry , Ocean temperature -- Physiological effect , Fishes -- Effect of temperature on
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/76530 , vital:30597
- Description: The leerfish (Lichia amia), is a large, primarily coastal recreational fish species with a distribution extending from Portugal down the west coast of African to southern Mozambique. Owing to its large size (30 kg), strong fighting abilities and habit of taking surface artificial lures, this species has taken on an iconic stature among shore-based recreational anglers. Its reputation has made it an important angling tourism species that makes an important contribution to the economy of developing countries. For example, the species brought US$243 per harvested kilogramme into the local southern Angola economy. Despite its high value, little is known about its movement patterns in the northern Benguela coastal region, a region which includes southern Angola and northern Namibia. While much is known about the migratory patterns of the South African stock of L. amia, recent molecular studies have shown that the northern Benguela stock of L. amia has been isolated from the South African population for at least two million years, a consequence of the development of the cold Lüderitz upwelling cell in southern Namibia. Although the global population of L. amia is considered a single species, prominent biogeographic barriers within its distribution and subtle morphological differences between specimens captured within its tropical versus warm-temperate distribution suggest otherwise. A multi-method approach incorporating passive acoustic telemetry (PAT), recreational catch-per-unit-effort (CPUE) and conventional tagging (CT) in southern Angola, as well as recreational fisher-ecological knowledge (FEK) from Namibia, was used to investigate the large-scale movement patterns of L. amia within the northern Benguela coastal region. While each method had its own associated limitations, the combination provided a holistic picture of the population's seasonal migratory patterns. Furthermore, PAT successfully identified partial migration with 25% vs 75% of monitored fish exhibiting resident (movements < 100 km) or migratory (movements > 100 km) behaviour, respectively. Further behavioural diversity was observed with ‘resident’, ‘roaming’ and ‘embayment’ contingents identified based on varying levels of affinity to certain habitats. The presence of both resident and migratory individuals within the northernmost study during June and July, combined with available biological information, suggested that area-specific spawning may take place. While PAT, CPUE and CT largely aligned in determining area specific high-area use, results from network analyses and mixed effects models conducted on the PAT data supported the spawning hypothesis, with anomalous behaviour around specific receivers during the spawning season. All fish, regardless of behavioural contingent, displayed similar movement behaviour during the spawning season and this was driven by factors generally associated with reproduction, such as lunar illumination. Interestingly, these drivers were different from those that determined the area specific use of individuals outside of the spawning season. The environmental drivers of longshore migration into the northern study site were identified as a decline in water temperature and shorter day lengths. The results of this study highlight the importance of using a multi-method approach in determining migratory movement behaviour, area specific area use, and stock structure of key fisheries species. The identification of different behavioural contingents highlights the importance of acknowledging individual variation in movement and habitat-use patterns. This is particularly relevant as future climate change and spatiotemporal variation in fishing effort may artificially skew natural selection processes to favour certain behavioural groups. This study also highlighted the importance of scientists forming relationships with resource-users, such as recreational angling lodges in areas where limited research has been conducted. This is particularly relevant within the West African context where little is known about many of the fish species that are being increasingly targeted by tourism angling ventures.
- Full Text:
- Date Issued: 2019
The fundamental right to just administrative action: judicial review of administrative action in the democratic South Africa
- Authors: Plasket, Clive
- Date: 2003
- Subjects: Judicial review of administrative acts -- South Africa Administrative acts -- South Africa Administrative law -- South Africa Public administration -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3693 , http://hdl.handle.net/10962/d1003208
- Description: For most of its existence South African administrative law has been shaped by the doctrine of parliamentary sovereignty – the heart of the constitutional order from 1910 to 1994 – and a racist political system that favoured the white minority at the expense of the black majority. In these circumstances, the rules of administrative law were of limited use in protecting the individual from exercises of administrative power that infringed fundamental human rights, often on a grand scale. On 27 April 1994, however, a new political and constitutional order came into existence that swept away the very foundations of the old order: parliamentary sovereignty was replaced by constitutional supremacy and the racial exclusivity of the old order was replaced by a commitment to equality, freedom and dignity in a democratic state. A justiciable Bill of Rights was at centre stage in this new order. That Bill of Rights includes a fundamental right to just administrative action. It is both the new constitutional order and this rather unusual fundamental right that have changed the nature of South African administrative law. This thesis examines the effect of the fundamental right to just administrative action on the law and practice of the judicial review of administrative action. It does so principally by examining the legal position before and after 27 April 1994 with particular reference to: what is meant by administrative action; the exercise of administrative power by private bodies regulated by the rules of administrative law, on the one hand, and exercises of private power regulated by rules of private law, on the other; the rules of standing, the notion of justiciability and the constitutionality of rules that seek to limit the right of the individual to approach a court to review administrative action; the meaning and scope of the right to lawful, reasonable and procedurally fair administrative action, in terms of the common law, the Constitution and the Promotion of Administrative Justice Act 3 of 2000; the meaning, scope and efficacy of the rights to reasons for administrative actions and of access to information; the procedure of judicial review and remedies that may be granted for the infringement of a person’s right to just administrative action; and conclusions and recommendations with regard to progress made in the construction of South Africa’s new, democratically based, administrative law.
- Full Text:
- Date Issued: 2003
- Authors: Plasket, Clive
- Date: 2003
- Subjects: Judicial review of administrative acts -- South Africa Administrative acts -- South Africa Administrative law -- South Africa Public administration -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3693 , http://hdl.handle.net/10962/d1003208
- Description: For most of its existence South African administrative law has been shaped by the doctrine of parliamentary sovereignty – the heart of the constitutional order from 1910 to 1994 – and a racist political system that favoured the white minority at the expense of the black majority. In these circumstances, the rules of administrative law were of limited use in protecting the individual from exercises of administrative power that infringed fundamental human rights, often on a grand scale. On 27 April 1994, however, a new political and constitutional order came into existence that swept away the very foundations of the old order: parliamentary sovereignty was replaced by constitutional supremacy and the racial exclusivity of the old order was replaced by a commitment to equality, freedom and dignity in a democratic state. A justiciable Bill of Rights was at centre stage in this new order. That Bill of Rights includes a fundamental right to just administrative action. It is both the new constitutional order and this rather unusual fundamental right that have changed the nature of South African administrative law. This thesis examines the effect of the fundamental right to just administrative action on the law and practice of the judicial review of administrative action. It does so principally by examining the legal position before and after 27 April 1994 with particular reference to: what is meant by administrative action; the exercise of administrative power by private bodies regulated by the rules of administrative law, on the one hand, and exercises of private power regulated by rules of private law, on the other; the rules of standing, the notion of justiciability and the constitutionality of rules that seek to limit the right of the individual to approach a court to review administrative action; the meaning and scope of the right to lawful, reasonable and procedurally fair administrative action, in terms of the common law, the Constitution and the Promotion of Administrative Justice Act 3 of 2000; the meaning, scope and efficacy of the rights to reasons for administrative actions and of access to information; the procedure of judicial review and remedies that may be granted for the infringement of a person’s right to just administrative action; and conclusions and recommendations with regard to progress made in the construction of South Africa’s new, democratically based, administrative law.
- Full Text:
- Date Issued: 2003
The rehabilitative value of sub-economic housing as illustrated by Schauder Township, Port Elizabeth, Cape Province, Union of South Africa, 1938-1948
- Authors: Stoker, F M L
- Date: 1954
- Subjects: Housing rehabilitation -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3389 , http://hdl.handle.net/10962/d1014554
- Description: [From Introductory discussion]. The modern approach to any sociological problem is characterised by the attempt to analyse the contributory factors in such a way that their inter-active association is clearly discernible. The simple concept of "single cause and effect" is now recognised to be a traversity of social fact. Social Pathology, therefore, may be said to attempt to isolate the multiple factors involved in a given situation, and to endeavour to determine thelr mode of inter-action in order that remedial techniques may be applied effectively. Slum conditions are obviously pathologic, by which it is understood that the environment imposes strains upon the individual to which there is ineffective adjustment. The rehabilitation of such a population would involve the converse process, restoring individuals to a condition where they are able to cope in every respect with the demands of life at their respective class levels. It is very rare indeed that only a single factor is involved in a social pathological condition and for this reason it is quite possible that one- sided efforts at rehabilitation - such as the attempt to re-house ALL slum dwellers in sub-economic houses - have a tendency to increase the pathology in another direction. Rehabilitation must therefore be based on multi-factorial analysis in which allowance is, as far as possible, made for the inter-connection of each of the individual deviations from the normal. The aim of this thesis is to evaluate the effect of good housing conditions on the 2335 Coloured slum families re-housed in sub-economic houses at Schauder Township, Port Elizabeth, from the time that these houses were first available for occupancy.
- Full Text:
- Date Issued: 1954
- Authors: Stoker, F M L
- Date: 1954
- Subjects: Housing rehabilitation -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3389 , http://hdl.handle.net/10962/d1014554
- Description: [From Introductory discussion]. The modern approach to any sociological problem is characterised by the attempt to analyse the contributory factors in such a way that their inter-active association is clearly discernible. The simple concept of "single cause and effect" is now recognised to be a traversity of social fact. Social Pathology, therefore, may be said to attempt to isolate the multiple factors involved in a given situation, and to endeavour to determine thelr mode of inter-action in order that remedial techniques may be applied effectively. Slum conditions are obviously pathologic, by which it is understood that the environment imposes strains upon the individual to which there is ineffective adjustment. The rehabilitation of such a population would involve the converse process, restoring individuals to a condition where they are able to cope in every respect with the demands of life at their respective class levels. It is very rare indeed that only a single factor is involved in a social pathological condition and for this reason it is quite possible that one- sided efforts at rehabilitation - such as the attempt to re-house ALL slum dwellers in sub-economic houses - have a tendency to increase the pathology in another direction. Rehabilitation must therefore be based on multi-factorial analysis in which allowance is, as far as possible, made for the inter-connection of each of the individual deviations from the normal. The aim of this thesis is to evaluate the effect of good housing conditions on the 2335 Coloured slum families re-housed in sub-economic houses at Schauder Township, Port Elizabeth, from the time that these houses were first available for occupancy.
- Full Text:
- Date Issued: 1954