Mapping the pyrroloiminoquinone diversity produced by latrunculid sponges using tandem mass spectrometry-driven molecular networking
- Authors: Kalinski, Jarmo-Charles
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178468 , vital:42942
- Description: Access restricted until April 2023. , Thesis (PhD) -- Faculty of Science, Chemistry, 2021
- Full Text:
- Authors: Kalinski, Jarmo-Charles
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178468 , vital:42942
- Description: Access restricted until April 2023. , Thesis (PhD) -- Faculty of Science, Chemistry, 2021
- Full Text:
The development of an ionospheric storm-time index for the South African region
- Authors: Tshisaphungo, Mpho
- Date: 2021-04
- Subjects: Ionospheric storms -- South Africa , Global Positioning System , Neural networks (Computer science) , Regression analysis , Ionosondes , Auroral electrojet , Geomagnetic indexes , Magnetic storms -- South Africa
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178409 , vital:42937 , 10.21504/10962/178409
- Description: This thesis presents the development of a regional ionospheric storm-time model which forms the foundation of an index to provide a quick view of the ionospheric storm effects over South African mid-latitude region. The model is based on the foF2 measurements from four South African ionosonde stations. The data coverage for the model development over Grahamstown (33.3◦S, 26.5◦E), Hermanus (34.42◦S, 19.22◦E), Louisvale (28.50◦S, 21.20◦E), and Madimbo (22.39◦S, 30.88◦E) is 1996-2016, 2009-2016, 2000-2016, and 2000-2016 respectively. Data from the Global Positioning System (GPS) and radio occultation (RO) technique were used during validation. As the measure of either positive or negative storm effect, the variation of the critical frequency of the F2 layer (foF2) from the monthly median values (denoted as _foF2) is modeled. The modeling of _foF2 is based on only storm time data with the criteria of Dst 6 -50 nT and Kp > 4. The modeling methods used in the study were artificial neural network (ANN), linear regression (LR) and polynomial functions. The approach taken was to first test the modeling techniques on a single station before expanding the study to cover the regional aspect. The single station modeling was developed based on ionosonde data over Grahamstown. The inputs for the model which related to seasonal variation, diurnal variation, geomagnetic activity and solar activity were considered. For the geomagnetic activity, three indices namely; the symmetric disturbance in the horizontal component of the Earth’s magnetic field (SYM − H), the Auroral Electrojet (AE) index and local geomagnetic index A, were included as inputs. The performance of a single station model revealed that, of the three geomagnetic indices, SYM − H index has the largest contribution of 41% and 54% based on ANN and LR techniques respectively. The average correlation coefficients (R) for both ANN and LR models was 0.8, when validated during the selected storms falling within the period of model development. When validated using storms that fall outside the period of model development, the model gave R values of 0.6 and 0.5 for ANN and LR respectively. In addition, the GPS total electron content (TEC) derived measurements were used to estimate foF2 data. This is because there are more GPS receivers than ionosonde locations and the utilisation of this data increases the spatial coverage of the regional model. The estimation of foF2 from GPS TEC was done at GPS-ionosonde co-locations using polynomial functions. The average R values of 0.69 and 0.65 were obtained between actual and derived _foF2 over the co-locations and other GPS stations respectively. Validation of GPS TEC derived foF2 with RO data over regions out of ionospheric pierce points coverage with respect to ionosonde locations gave R greater than 0.9 for the selected storm period of 4-8 August 2011. The regional storm-time model was then developed based on the ANN technique using the four South African ionosonde stations. The maximum and minimum R values of 0.6 and 0.5 were obtained over ionosonde and GPS locations respectively. This model forms the basis towards the regional ionospheric storm-time index. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2021
- Full Text:
- Authors: Tshisaphungo, Mpho
- Date: 2021-04
- Subjects: Ionospheric storms -- South Africa , Global Positioning System , Neural networks (Computer science) , Regression analysis , Ionosondes , Auroral electrojet , Geomagnetic indexes , Magnetic storms -- South Africa
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178409 , vital:42937 , 10.21504/10962/178409
- Description: This thesis presents the development of a regional ionospheric storm-time model which forms the foundation of an index to provide a quick view of the ionospheric storm effects over South African mid-latitude region. The model is based on the foF2 measurements from four South African ionosonde stations. The data coverage for the model development over Grahamstown (33.3◦S, 26.5◦E), Hermanus (34.42◦S, 19.22◦E), Louisvale (28.50◦S, 21.20◦E), and Madimbo (22.39◦S, 30.88◦E) is 1996-2016, 2009-2016, 2000-2016, and 2000-2016 respectively. Data from the Global Positioning System (GPS) and radio occultation (RO) technique were used during validation. As the measure of either positive or negative storm effect, the variation of the critical frequency of the F2 layer (foF2) from the monthly median values (denoted as _foF2) is modeled. The modeling of _foF2 is based on only storm time data with the criteria of Dst 6 -50 nT and Kp > 4. The modeling methods used in the study were artificial neural network (ANN), linear regression (LR) and polynomial functions. The approach taken was to first test the modeling techniques on a single station before expanding the study to cover the regional aspect. The single station modeling was developed based on ionosonde data over Grahamstown. The inputs for the model which related to seasonal variation, diurnal variation, geomagnetic activity and solar activity were considered. For the geomagnetic activity, three indices namely; the symmetric disturbance in the horizontal component of the Earth’s magnetic field (SYM − H), the Auroral Electrojet (AE) index and local geomagnetic index A, were included as inputs. The performance of a single station model revealed that, of the three geomagnetic indices, SYM − H index has the largest contribution of 41% and 54% based on ANN and LR techniques respectively. The average correlation coefficients (R) for both ANN and LR models was 0.8, when validated during the selected storms falling within the period of model development. When validated using storms that fall outside the period of model development, the model gave R values of 0.6 and 0.5 for ANN and LR respectively. In addition, the GPS total electron content (TEC) derived measurements were used to estimate foF2 data. This is because there are more GPS receivers than ionosonde locations and the utilisation of this data increases the spatial coverage of the regional model. The estimation of foF2 from GPS TEC was done at GPS-ionosonde co-locations using polynomial functions. The average R values of 0.69 and 0.65 were obtained between actual and derived _foF2 over the co-locations and other GPS stations respectively. Validation of GPS TEC derived foF2 with RO data over regions out of ionospheric pierce points coverage with respect to ionosonde locations gave R greater than 0.9 for the selected storm period of 4-8 August 2011. The regional storm-time model was then developed based on the ANN technique using the four South African ionosonde stations. The maximum and minimum R values of 0.6 and 0.5 were obtained over ionosonde and GPS locations respectively. This model forms the basis towards the regional ionospheric storm-time index. , Thesis (PhD) -- Faculty of Science, Physics and Electronics, 2021
- Full Text:
The effect of various substrate pretreatment methods on the enzymatic degradability of a Eucalyptus sp. – a potential feedstock for producing fermentable sugars
- Authors: Thoresen, Mariska
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178580 , vital:42952
- Description: Access restricted until April 2022. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
- Authors: Thoresen, Mariska
- Date: 2021-04
- Subjects: To be added
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178580 , vital:42952
- Description: Access restricted until April 2022. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2021
- Full Text:
The effects of aspect, directional heating and depth on bedrock temperatures and the potential relationship with thermal fatigue weathering
- Authors: Breytenbach, Izak Johannes
- Date: 2021-04
- Subjects: Weathering -- South Africa -- Karoo , Shields (Geology) -- South Africa -- Karoo , Shields (Geology) -- Thermal properties , Tillite -- South Africa -- Karoo
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177688 , vital:42847 , 10.21504/10962/177688
- Description: Geomorphological weathering processes and their relationship with temperature fluctuations are frequently researched. These research efforts are mostly restricted to surface conditions where soils, loose-lying rocks or rock outcrops are assessed. However, there is a shortcoming in the understanding of the thermal properties in a rock mass, particularly in the upper metres below the surface, as this has not been investigated or researched in any great detail. The research reported here is unique in this regard as it exploited the use of rotary core boreholes in tillite bedrock in the Karoo (Western Cape, South Africa) which were drilled as part of an invasive materials investigation for a proposed new hard rock quarry to supply road stone. Temperature data were captured on a bedrock ridge hosting tillite outcrop with a strong east to west orientation. The site work was done in two separate phases. The initial phase of research saw data being captured for one year on two aspects (i.e. north and south) at a depth of 0.3 m. This was followed by the second (more detailed) phase, where three aspects were assessed (i.e. north, south and a flat crest), but at depths of 0.3 m, 2.0 m and 6.0 m, totalling nine data acquisition points. The second investigation phase gathered data for seven months. Supplementary weather data were also captured for the site. Subsequent data analyses revealed that there is much to learn about the thermal behaviour of bedrock in the upper metres below the surface, and that the temperature properties or thermal regimes are not as simple as often assumed. Temperature differences related to aspect are not only surficial, but are transmitted to underlying bedrock, and notable temperature differences were measurable to a depth of at least 6.0 m. Seasonal temperature fluctuations also have a pronounced effect on the rock mass temperatures and it was proven that deeper parts of the bedrock accumulate and dissipate heat at different (i.e. retarded) rates compared with shallower parts of the rock mass, creating suitable thermal conditions to induce thermal fatigue. Thermal properties were also proven to be non-linear. During analyses, the concept of temperature inversions was proven, whereby one part of the bedrock becomes hotter or cooler relative to another/adjacent part of the bedrock, compared with its earlier temperature state. It was argued that these temperature inversions may exacerbate thermal fatigue. This research proved that aspect (i.e. directional heating) and depth need to be considered when analysing thermal regimes in a rock mass, as these have a distinct influence. The effects which manifest themselves create suitable conditions for thermal fatigue, not only near the surface but also at depth in the bedrock. Lastly, the effects of meteorological conditions on shallow bedrock temperatures were assessed. Preliminary findings suggest that boundary conditions and meteorological processes may indeed affect shallow bedrock temperatures, but only under certain circumstances and not to the same extent as reported in the literature for conditions researched at the surface. Wind temperature relative to the rock temperature, as well as a combination of wind and rain were found to be the most significant factors. , Thesis (PhD) -- Faculty of Science, Geography, 2021
- Full Text:
- Authors: Breytenbach, Izak Johannes
- Date: 2021-04
- Subjects: Weathering -- South Africa -- Karoo , Shields (Geology) -- South Africa -- Karoo , Shields (Geology) -- Thermal properties , Tillite -- South Africa -- Karoo
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177688 , vital:42847 , 10.21504/10962/177688
- Description: Geomorphological weathering processes and their relationship with temperature fluctuations are frequently researched. These research efforts are mostly restricted to surface conditions where soils, loose-lying rocks or rock outcrops are assessed. However, there is a shortcoming in the understanding of the thermal properties in a rock mass, particularly in the upper metres below the surface, as this has not been investigated or researched in any great detail. The research reported here is unique in this regard as it exploited the use of rotary core boreholes in tillite bedrock in the Karoo (Western Cape, South Africa) which were drilled as part of an invasive materials investigation for a proposed new hard rock quarry to supply road stone. Temperature data were captured on a bedrock ridge hosting tillite outcrop with a strong east to west orientation. The site work was done in two separate phases. The initial phase of research saw data being captured for one year on two aspects (i.e. north and south) at a depth of 0.3 m. This was followed by the second (more detailed) phase, where three aspects were assessed (i.e. north, south and a flat crest), but at depths of 0.3 m, 2.0 m and 6.0 m, totalling nine data acquisition points. The second investigation phase gathered data for seven months. Supplementary weather data were also captured for the site. Subsequent data analyses revealed that there is much to learn about the thermal behaviour of bedrock in the upper metres below the surface, and that the temperature properties or thermal regimes are not as simple as often assumed. Temperature differences related to aspect are not only surficial, but are transmitted to underlying bedrock, and notable temperature differences were measurable to a depth of at least 6.0 m. Seasonal temperature fluctuations also have a pronounced effect on the rock mass temperatures and it was proven that deeper parts of the bedrock accumulate and dissipate heat at different (i.e. retarded) rates compared with shallower parts of the rock mass, creating suitable thermal conditions to induce thermal fatigue. Thermal properties were also proven to be non-linear. During analyses, the concept of temperature inversions was proven, whereby one part of the bedrock becomes hotter or cooler relative to another/adjacent part of the bedrock, compared with its earlier temperature state. It was argued that these temperature inversions may exacerbate thermal fatigue. This research proved that aspect (i.e. directional heating) and depth need to be considered when analysing thermal regimes in a rock mass, as these have a distinct influence. The effects which manifest themselves create suitable conditions for thermal fatigue, not only near the surface but also at depth in the bedrock. Lastly, the effects of meteorological conditions on shallow bedrock temperatures were assessed. Preliminary findings suggest that boundary conditions and meteorological processes may indeed affect shallow bedrock temperatures, but only under certain circumstances and not to the same extent as reported in the literature for conditions researched at the surface. Wind temperature relative to the rock temperature, as well as a combination of wind and rain were found to be the most significant factors. , Thesis (PhD) -- Faculty of Science, Geography, 2021
- Full Text:
The further development, application and evaluation of a sediment yield model (WQSED) for catchment management in African catchments
- Authors: Gwapedza, David
- Date: 2021-04
- Subjects: Sedimentation and deposition -- South Africa , Sedimentation and deposition -- Zimbabwe , Watersheds -- South Africa , Watersheds -- Zimbabwe , Watershed management -- Africa , Water quality -- South Africa , Water quality -- Zimbabwe , Modified Universal Soil Loss Equation (MUSLE) , Water Quality and Sediment Model (WQSED) , Soil and Water Assessment Tool (SWAT)
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178376 , vital:42934 , 10.21504/10962/178376
- Description: Erosion and sediment transport are natural catchment processes that play an essential role in ecosystem functioning by providing habitat for aquatic organisms and contributing to the health of wetlands. However, excessive erosion and sedimentation, mostly driven by anthropogenic activity, lead to ecosystem degradation, loss of agricultural land, water quality problems, reduced reservoir storage capacity and damage to physical infrastructure. It is reported that up to 25% of dams in South Africa have lost approximately 30% of their initial storage capacity to sedimentation. Therefore, excessive sedimentation transcends from an ecological problem to a health, livelihood and water security issue. Erosion and sedimentation occur at variable temporal and spatial scales; therefore, monitoring of these processes can be difficult and expensive. Regardless of all these prohibiting factors, information on erosion and sediment remains an urgent requirement for the sustainable management of catchments. Models have evolved as tools to replicate and simulate complex natural processes to understand and manage these systems. Several models have been developed globally to simulate erosion and sediment transport. However, these models are not always applicable in Africa because 1) the conditions under which they were developed are not as relevant for African catchments 2) they have high data requirements and cannot be applied with ease in our data-scarce African catchments 3) they are sometimes complicated, and there are little training available or potential users simply have no time to dedicate towards learning these models. To respond to the problems of erosion, sedimentation, water quality and unavailability of applicable models, the current research further develops, applies and evaluates an erosion and sediment transport model, the Water Quality and Sediment Model (WQSED), for integration within the existing water resources framework in South Africa and application for practical catchment management. The WQSED was developed to simulate daily suspended sediment loads that are vital for water quality and quantity assessments. The WQSED was developed based on the Modified Universal Soil Loss Equation (MUSLE), and the Pitman model is a primary hydrological model providing forcing data, although flow data from independent sources may be used to drive the WQSED model. The MUSLE was developed in the United States of America, and this research attempts to improve the applicability of the MUSLE by identifying key issues that may impede its performance. Assessments conducted within the current research can be divided into scale assessment and application and evaluation assessment. The scale assessment involved evaluating spatial and temporal scale issues associated with the MUSLE. Spatial scale assessments were conducted using analytical and mathematical assessments on a hypothetical catchment. Temporal scale issues were assessed in terms of the vegetation cover (C) factor within the Tsitsa River catchment in South Africa. Model application and evaluation involved applying and calibrating the model to simulate daily time-series sediment yield. The model was applied to calibrated and validated (split-sample validation) in two catchments in South Africa, two catchments in Zimbabwe and three catchments were selected from the USA and associated territories for further testing as continuous daily time-series observed sediment data could not be readily accessed for catchments in the Southern African region. The catchments where the model was calibrated and validated range in size from 50 km2 to 20 000 km2. Additionally, the model was applied to thirteen ‘ungauged’ catchments selected from across South Africa, where only long-term reservoir sedimentation rates were available to compare with long term model simulations converted to sediment yield rates. The additional thirteen catchments were selected from areas of different climatic, vegetation and soils conditions characterising South Africa and range in size from 30 km2 to 2 500 km2. The current research results are split into a) MUSLE scale dependency and b) WQSED testing and evaluation. Scale dependency testing showed that the MUSLE could be spatially scale-dependent, particularly when a lumped approach is used, resulting in simulations of up to 30% more sediment. Spatial scale dependence in the MUSLE was found to be related to the runoff and topographic factors used and how they are calculated. The current study resorted to adopting a reference grid in applying the MUSLE, followed by scaling up the outputs to the total catchment area. Using a reference grid resulted in a general avoidance of the problem of spatial scale. The adoption of a seasonal vegetation cover factor was shown to significantly account for temporal changes of vegetation cover within a year and reduce over-estimations in sediment output. The temporal scale evaluation demonstrated the uncertainties associated with using a fixed vegetation cover factor in a catchment with variable rainfall and runoff pattern. The WQSED model evaluation showed that the model could be calibrated and validated to provide consistent results. Satisfactory model evaluation statistics were obtained for most catchments to which the model was applied, based on general model evaluation guidelines (Nash Sutcliffe Efficiency and R2 > 0.5). The model also performed generally well compared to established models that had been previously applied in some of the study catchments. The highest sediment yields recorded per country were 153 t km-2 year-1 (Tsitsa River; South Africa), 90 t km-2 year-1 (Odzi River; Zimbabwe) and 340 t km-2 year-1 (Rio Tanama; Puerto Rico). The results also displayed consistent underestimations of peak sediment yield events, partly attributed to sediment emanating from gullies that are not explicitly accounted for in the WQSED model structure. Furthermore, the calibration process revealed that the WQSED storage model is generally challenging to calibrate. An alternative simpler version of the storage model was easier to calibrate, but the model may still be challenging to apply to catchments where calibration data are not available. The additional evaluation of the WQSED simulated sediment yield rates against observed reservoir sediment rates showed a broad range of differences between the simulated and observed sediment yield rates. Differences between WQSED simulated sediment and observed reservoir sediment ranges from a low of 30% to a high of > 40 times. The large differences were partly attributed to WQSED being limited to simulating suspended sediment from sheet and rill processes, whereas reservoir sediment is generated from more sources that include bedload, channel and gully processes. Nevertheless, the model simulations replicated some of the regional sediment yield patterns and are assumed to represent sheet and rill contributions to reservoir sediment in selected catchments. The outcome of this study is an improved WQSED model that has successfully undergone preliminary testing and evaluation. Therefore, the model is sufficiently complete to be used by independent researchers and water resources managers to simulate erosion and sediment transport. However, the model is best applicable to areas where some observed data or regional information are available to calibrate the storage components and constrain model outputs. The report on potential MUSLE scale dependencies is relevant globally to all studies applying the MUSLE model and, therefore, can improve MUSLE application in future studies. The WQSED model offers a relatively simple, effective and applicable tool that is set to provide information to enhance catchment, land and water resources management in catchments of Africa. , Thesis (PhD) -- Faculty of Science, Institute for Water Research, 2021
- Full Text:
- Authors: Gwapedza, David
- Date: 2021-04
- Subjects: Sedimentation and deposition -- South Africa , Sedimentation and deposition -- Zimbabwe , Watersheds -- South Africa , Watersheds -- Zimbabwe , Watershed management -- Africa , Water quality -- South Africa , Water quality -- Zimbabwe , Modified Universal Soil Loss Equation (MUSLE) , Water Quality and Sediment Model (WQSED) , Soil and Water Assessment Tool (SWAT)
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178376 , vital:42934 , 10.21504/10962/178376
- Description: Erosion and sediment transport are natural catchment processes that play an essential role in ecosystem functioning by providing habitat for aquatic organisms and contributing to the health of wetlands. However, excessive erosion and sedimentation, mostly driven by anthropogenic activity, lead to ecosystem degradation, loss of agricultural land, water quality problems, reduced reservoir storage capacity and damage to physical infrastructure. It is reported that up to 25% of dams in South Africa have lost approximately 30% of their initial storage capacity to sedimentation. Therefore, excessive sedimentation transcends from an ecological problem to a health, livelihood and water security issue. Erosion and sedimentation occur at variable temporal and spatial scales; therefore, monitoring of these processes can be difficult and expensive. Regardless of all these prohibiting factors, information on erosion and sediment remains an urgent requirement for the sustainable management of catchments. Models have evolved as tools to replicate and simulate complex natural processes to understand and manage these systems. Several models have been developed globally to simulate erosion and sediment transport. However, these models are not always applicable in Africa because 1) the conditions under which they were developed are not as relevant for African catchments 2) they have high data requirements and cannot be applied with ease in our data-scarce African catchments 3) they are sometimes complicated, and there are little training available or potential users simply have no time to dedicate towards learning these models. To respond to the problems of erosion, sedimentation, water quality and unavailability of applicable models, the current research further develops, applies and evaluates an erosion and sediment transport model, the Water Quality and Sediment Model (WQSED), for integration within the existing water resources framework in South Africa and application for practical catchment management. The WQSED was developed to simulate daily suspended sediment loads that are vital for water quality and quantity assessments. The WQSED was developed based on the Modified Universal Soil Loss Equation (MUSLE), and the Pitman model is a primary hydrological model providing forcing data, although flow data from independent sources may be used to drive the WQSED model. The MUSLE was developed in the United States of America, and this research attempts to improve the applicability of the MUSLE by identifying key issues that may impede its performance. Assessments conducted within the current research can be divided into scale assessment and application and evaluation assessment. The scale assessment involved evaluating spatial and temporal scale issues associated with the MUSLE. Spatial scale assessments were conducted using analytical and mathematical assessments on a hypothetical catchment. Temporal scale issues were assessed in terms of the vegetation cover (C) factor within the Tsitsa River catchment in South Africa. Model application and evaluation involved applying and calibrating the model to simulate daily time-series sediment yield. The model was applied to calibrated and validated (split-sample validation) in two catchments in South Africa, two catchments in Zimbabwe and three catchments were selected from the USA and associated territories for further testing as continuous daily time-series observed sediment data could not be readily accessed for catchments in the Southern African region. The catchments where the model was calibrated and validated range in size from 50 km2 to 20 000 km2. Additionally, the model was applied to thirteen ‘ungauged’ catchments selected from across South Africa, where only long-term reservoir sedimentation rates were available to compare with long term model simulations converted to sediment yield rates. The additional thirteen catchments were selected from areas of different climatic, vegetation and soils conditions characterising South Africa and range in size from 30 km2 to 2 500 km2. The current research results are split into a) MUSLE scale dependency and b) WQSED testing and evaluation. Scale dependency testing showed that the MUSLE could be spatially scale-dependent, particularly when a lumped approach is used, resulting in simulations of up to 30% more sediment. Spatial scale dependence in the MUSLE was found to be related to the runoff and topographic factors used and how they are calculated. The current study resorted to adopting a reference grid in applying the MUSLE, followed by scaling up the outputs to the total catchment area. Using a reference grid resulted in a general avoidance of the problem of spatial scale. The adoption of a seasonal vegetation cover factor was shown to significantly account for temporal changes of vegetation cover within a year and reduce over-estimations in sediment output. The temporal scale evaluation demonstrated the uncertainties associated with using a fixed vegetation cover factor in a catchment with variable rainfall and runoff pattern. The WQSED model evaluation showed that the model could be calibrated and validated to provide consistent results. Satisfactory model evaluation statistics were obtained for most catchments to which the model was applied, based on general model evaluation guidelines (Nash Sutcliffe Efficiency and R2 > 0.5). The model also performed generally well compared to established models that had been previously applied in some of the study catchments. The highest sediment yields recorded per country were 153 t km-2 year-1 (Tsitsa River; South Africa), 90 t km-2 year-1 (Odzi River; Zimbabwe) and 340 t km-2 year-1 (Rio Tanama; Puerto Rico). The results also displayed consistent underestimations of peak sediment yield events, partly attributed to sediment emanating from gullies that are not explicitly accounted for in the WQSED model structure. Furthermore, the calibration process revealed that the WQSED storage model is generally challenging to calibrate. An alternative simpler version of the storage model was easier to calibrate, but the model may still be challenging to apply to catchments where calibration data are not available. The additional evaluation of the WQSED simulated sediment yield rates against observed reservoir sediment rates showed a broad range of differences between the simulated and observed sediment yield rates. Differences between WQSED simulated sediment and observed reservoir sediment ranges from a low of 30% to a high of > 40 times. The large differences were partly attributed to WQSED being limited to simulating suspended sediment from sheet and rill processes, whereas reservoir sediment is generated from more sources that include bedload, channel and gully processes. Nevertheless, the model simulations replicated some of the regional sediment yield patterns and are assumed to represent sheet and rill contributions to reservoir sediment in selected catchments. The outcome of this study is an improved WQSED model that has successfully undergone preliminary testing and evaluation. Therefore, the model is sufficiently complete to be used by independent researchers and water resources managers to simulate erosion and sediment transport. However, the model is best applicable to areas where some observed data or regional information are available to calibrate the storage components and constrain model outputs. The report on potential MUSLE scale dependencies is relevant globally to all studies applying the MUSLE model and, therefore, can improve MUSLE application in future studies. The WQSED model offers a relatively simple, effective and applicable tool that is set to provide information to enhance catchment, land and water resources management in catchments of Africa. , Thesis (PhD) -- Faculty of Science, Institute for Water Research, 2021
- Full Text:
The impact of translanguaging and acculturation towards implementation of the Incremental Indigenous African Languages programme in former Model-C schools (Alfred Nzo West District, Eastern Cape)
- Authors: Lepheana, Jeremia
- Date: 2021-04
- Subjects: Translanguaging (Linguistics) , Acculturation -- South Africa -- Eastern Cape , Model C schools (South Africa) , Multilingual education -- South Africa -- Eastern Cape , Multicultural education -- South Africa -- Eastern Cape , Incremental Indigenous African Languages Programme
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177236 , vital:42802 , 10.21504/10962/177236
- Description: This thesis explores the possibilities of multilingual language instruction within multi-ethnic classrooms in former Model-C schools shaped by multiple discursive practices. The researcher reviews current research on multilingualism and teaching and proposes strategies for overcoming the English prescriptivism, and monolingual mind-set in education. The research reported in this dissertation is both a qualitative and quantitative study, which sought to investigate the patterns of translanguaging in classrooms in five primary schools in Alfred Nzo West district (Maluti sub-district). In quantitative research, questionnaires were used to gather data from teachers and learners. In the qualitative research methodology, document analysis method of collecting data was employed. Purposive sampling was the major sampling method to ensure that relevant data was collected. Language in Education Policy formed the major analytical framework for this study. The aim of the study was to investigate the impact of translanguaging as it is used by teachers and learners in the class in selected primary schools in Alfred Nzo West district. The research focuses on how primary school learners and their teachers engage with teaching and learning, and the strategies that teachers use to promote the use of two or three languages in classrooms to help learners to understand content and concepts in English, Sesotho and isiXhosa as there are multi-ethnic classrooms in the district. The dissertation concludes with some reflections on the findings, implications of the findings for future research and training, and recommendations to use the languages of school children as rich resources for teaching and learning. The Socio-cultural theory formed the theoretical framework that guided this study. According to Vygotsky’s theory of cognitive development, children learn through social interaction that includes collaborative and cooperative dialogue with someone who is more skilled in tasks they are trying to learn. The findings of this study show the misunderstandings of the LiEP, translanguaging and multilingual education. The study also shows the lack of confidence in the ability of African languages to provide quality education. , Thesis (PhD) -- Faculty of Humanities, School of Languages, 2021
- Full Text:
- Authors: Lepheana, Jeremia
- Date: 2021-04
- Subjects: Translanguaging (Linguistics) , Acculturation -- South Africa -- Eastern Cape , Model C schools (South Africa) , Multilingual education -- South Africa -- Eastern Cape , Multicultural education -- South Africa -- Eastern Cape , Incremental Indigenous African Languages Programme
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177236 , vital:42802 , 10.21504/10962/177236
- Description: This thesis explores the possibilities of multilingual language instruction within multi-ethnic classrooms in former Model-C schools shaped by multiple discursive practices. The researcher reviews current research on multilingualism and teaching and proposes strategies for overcoming the English prescriptivism, and monolingual mind-set in education. The research reported in this dissertation is both a qualitative and quantitative study, which sought to investigate the patterns of translanguaging in classrooms in five primary schools in Alfred Nzo West district (Maluti sub-district). In quantitative research, questionnaires were used to gather data from teachers and learners. In the qualitative research methodology, document analysis method of collecting data was employed. Purposive sampling was the major sampling method to ensure that relevant data was collected. Language in Education Policy formed the major analytical framework for this study. The aim of the study was to investigate the impact of translanguaging as it is used by teachers and learners in the class in selected primary schools in Alfred Nzo West district. The research focuses on how primary school learners and their teachers engage with teaching and learning, and the strategies that teachers use to promote the use of two or three languages in classrooms to help learners to understand content and concepts in English, Sesotho and isiXhosa as there are multi-ethnic classrooms in the district. The dissertation concludes with some reflections on the findings, implications of the findings for future research and training, and recommendations to use the languages of school children as rich resources for teaching and learning. The Socio-cultural theory formed the theoretical framework that guided this study. According to Vygotsky’s theory of cognitive development, children learn through social interaction that includes collaborative and cooperative dialogue with someone who is more skilled in tasks they are trying to learn. The findings of this study show the misunderstandings of the LiEP, translanguaging and multilingual education. The study also shows the lack of confidence in the ability of African languages to provide quality education. , Thesis (PhD) -- Faculty of Humanities, School of Languages, 2021
- Full Text:
The Influence of Clientelism on the Informal Sector in Zimbabwe : a Case Study of Glen View 8 Complex, Harare
- Authors: Tandire, Justin
- Date: 2021-04
- Subjects: Patron and client -- Zimbabwe -- Harare , Informal sector (Economics) -- Zimbabwe -- Harare , Informal sector (Economics) -- Political aspects -- Zimbabwe -- Harare , Patronage, Political -- Zimbabwe -- Harare , ZANU-PF (Organization : Zimbabwe) , Zimbabwe -- Social conditions , Glen View Complex 8 (Zimbabwe)
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177986 , vital:42896 , 10.21504/10962/177986
- Description: This study focuses on the influence of clientelism in the informal sector of Zimbabwe in Glen View 8 (Complex). The study used the case of Glen view 8 (complex) in Harare Province. The study focused on political dynamics in the informal sector; livelihood strategies employed by informal sector operators; manifestation of “Big Men”, social networks in the informal sector; and different strategies employed by operators to overcome the problems of political manipulation, clientelism and patronage. It employs a qualitative research methodology to enable a nuanced comprehension of the clientelistic relationships that take place in the informal sector of Zimbabwe. Through in-depth interviews, focus group discussions, narratives and in-depth interviews with key informants, the study explored the clientelistic nature of the informal sector. The major findings of the study are that the informal sector in Zimbabwe is influenced by political patronage. It was established that patronage influences the informal sector in Zimbabwe in general and at Glen View Complex 8 in particular. Some of the operators revealed that patronage negatively affects their business as they are sometimes forced to attend political party meetings either at the complex or at ZANU-PF star rallies in town. The operators experience a plethora of problems such as lack of security, poor sanitation, stiff competition, poor infrastructure, lack of insurance and fire outbreaks. It has been revealed that most of the problems experienced at the complex are a result of the politicisation of the informal sector particularly by the ZANU-PF party. Operators at the complex have described the politicisation of the informal sector as a major drawback to their efforts of realising maximum benefits from their work. Therefore, the thrust of this thesis is premised on the de-politicisation of the informal sector as the starting point in the transformation of the activities of the operators. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2021
- Full Text:
- Authors: Tandire, Justin
- Date: 2021-04
- Subjects: Patron and client -- Zimbabwe -- Harare , Informal sector (Economics) -- Zimbabwe -- Harare , Informal sector (Economics) -- Political aspects -- Zimbabwe -- Harare , Patronage, Political -- Zimbabwe -- Harare , ZANU-PF (Organization : Zimbabwe) , Zimbabwe -- Social conditions , Glen View Complex 8 (Zimbabwe)
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177986 , vital:42896 , 10.21504/10962/177986
- Description: This study focuses on the influence of clientelism in the informal sector of Zimbabwe in Glen View 8 (Complex). The study used the case of Glen view 8 (complex) in Harare Province. The study focused on political dynamics in the informal sector; livelihood strategies employed by informal sector operators; manifestation of “Big Men”, social networks in the informal sector; and different strategies employed by operators to overcome the problems of political manipulation, clientelism and patronage. It employs a qualitative research methodology to enable a nuanced comprehension of the clientelistic relationships that take place in the informal sector of Zimbabwe. Through in-depth interviews, focus group discussions, narratives and in-depth interviews with key informants, the study explored the clientelistic nature of the informal sector. The major findings of the study are that the informal sector in Zimbabwe is influenced by political patronage. It was established that patronage influences the informal sector in Zimbabwe in general and at Glen View Complex 8 in particular. Some of the operators revealed that patronage negatively affects their business as they are sometimes forced to attend political party meetings either at the complex or at ZANU-PF star rallies in town. The operators experience a plethora of problems such as lack of security, poor sanitation, stiff competition, poor infrastructure, lack of insurance and fire outbreaks. It has been revealed that most of the problems experienced at the complex are a result of the politicisation of the informal sector particularly by the ZANU-PF party. Operators at the complex have described the politicisation of the informal sector as a major drawback to their efforts of realising maximum benefits from their work. Therefore, the thrust of this thesis is premised on the de-politicisation of the informal sector as the starting point in the transformation of the activities of the operators. , Thesis (PhD) -- Faculty of Humanities, Sociology, 2021
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The role of open government data in the repurposing of land administration in postapartheid South Africa : an exploration
- Authors: Manona, Siyabulela Sobantu
- Date: 2021-04
- Subjects: Transparency in government -- South Africa , Land reform -- South Africa , Qualitative research -- Methodology , Postcolonialism -- South Africa , Post-apartheid era -- South Africa , South Africa -- Economic conditions -- 1991- , South Africa -- Social conditions -- 1994- , South Africa -- Politics and government -- 1994- , Open Government Data (OGD)
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178397 , vital:42936 , 10.21504/10962/178397
- Description: Almost three decades after the official end of the apartheid, South Africa has been on a sturdy path that is characterised by deepening spatial economic inequalities. A plethora of policy instruments unleashed since 1994 had not only failed to stem the tide of poverty and inequality, but had deepened them. As part of this, South Africa’s most ambitious social engineering programme – land reform -- had disappointing outcomes. Premised on a view that these apartheid continuities were embedded in South Africa’s land administration system – which was incoherent and fragmented and requiring a systemic overhaul -- the study sought to explore the potential role of Open Government Data (OGD) in the repurposing of land administration system in the post-apartheid South Africa. To achieve this goal, the study was guided by the following objectives: to explore the ontology and the state of land governance and administration in the context of the post-apartheid South Africa; to undertake an evaluation or assessment of South Africa’s land data ecosystem; and to explore the potential role of OGD in the repurposing of land administration system in the postapartheid of South Africa. This study was steeped in qualitative research methods, underpinned by primary and secondary literature review. While the study was primarily pitched on a national scale – the combination of the systems and multiple scales approaches – yielded results which dislodges solutions that are required outside of the domain of a single state. This is one glaring example of land governance complexities that straddle beyond national scale – specifically in respect of new policy trajectories on trans-national boundaries and governance of water resources. Based on the holistic ontology of land, this study concludes that land administration and land governance overarching conceptual orientation -- concerned with land use decisions made by humans at various scales from a praxis and policy perspective –constitute two sides of the same coin, the former steeped towards practice and the latter steeped towards policy. Drawing from decolonial theories the study concludes that land does not only have multiple dimensions, but it also has multiple meanings, in a manner that calls for an ontological shift away from the western ontology, towards an inclusive and holistic conceptualisation. Historiography that is anchored in de-colonial thinking of South Africa’s land governance helps us understand how and why – colonial/apartheid norms acrimoniously found their way into the post-apartheid order -- the post-apartheid institutions of modernity rest on the same hierarchies of identities, classification and pathologisation. The study concludes that, while the colonial/apartheid administration may be gone, it’s underlying power matrices continue -- i.e. capitalism/European/patriachal/white – in a manner which explains the continuities of South Africa’s spatial inequalities and the associated economic inequalities. The organising principle for land relations (including opportunities) continues to be underpinned by gender, race and class, in ways that expose the mythical dimensions of the 'post-apartheid' underbelly. While identifying the need for homogenisation and rationalistion of colonial, apartheid and post-apartheid institutions (on a national scale) that is insufficient for the transformation of the colonial situation of what is in essence a part of the global system, the study advocates for the ‘repurposing of land governance and administration’ – underpinned by de-colonial thinking. Repurposing is seen as political imaginary that would entail uncoupling thought processes and praxis from the colonial matrices of power. The study goes on to conclude that there is a definite role for Open Government Data in repurposing of land administration in the post-apartheid South Africa – as a necessary, though in and of it’s own it is an insufficient condition to achieve that ideal -- but presents an opportunity to enhance transdisciplinarity approaches and efficiencies in internal government functioning and evidence-based decision making and policy formulation processes. , Thesis (PhD) -- Faculty of Science, Geography, 2021
- Full Text:
- Authors: Manona, Siyabulela Sobantu
- Date: 2021-04
- Subjects: Transparency in government -- South Africa , Land reform -- South Africa , Qualitative research -- Methodology , Postcolonialism -- South Africa , Post-apartheid era -- South Africa , South Africa -- Economic conditions -- 1991- , South Africa -- Social conditions -- 1994- , South Africa -- Politics and government -- 1994- , Open Government Data (OGD)
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/178397 , vital:42936 , 10.21504/10962/178397
- Description: Almost three decades after the official end of the apartheid, South Africa has been on a sturdy path that is characterised by deepening spatial economic inequalities. A plethora of policy instruments unleashed since 1994 had not only failed to stem the tide of poverty and inequality, but had deepened them. As part of this, South Africa’s most ambitious social engineering programme – land reform -- had disappointing outcomes. Premised on a view that these apartheid continuities were embedded in South Africa’s land administration system – which was incoherent and fragmented and requiring a systemic overhaul -- the study sought to explore the potential role of Open Government Data (OGD) in the repurposing of land administration system in the post-apartheid South Africa. To achieve this goal, the study was guided by the following objectives: to explore the ontology and the state of land governance and administration in the context of the post-apartheid South Africa; to undertake an evaluation or assessment of South Africa’s land data ecosystem; and to explore the potential role of OGD in the repurposing of land administration system in the postapartheid of South Africa. This study was steeped in qualitative research methods, underpinned by primary and secondary literature review. While the study was primarily pitched on a national scale – the combination of the systems and multiple scales approaches – yielded results which dislodges solutions that are required outside of the domain of a single state. This is one glaring example of land governance complexities that straddle beyond national scale – specifically in respect of new policy trajectories on trans-national boundaries and governance of water resources. Based on the holistic ontology of land, this study concludes that land administration and land governance overarching conceptual orientation -- concerned with land use decisions made by humans at various scales from a praxis and policy perspective –constitute two sides of the same coin, the former steeped towards practice and the latter steeped towards policy. Drawing from decolonial theories the study concludes that land does not only have multiple dimensions, but it also has multiple meanings, in a manner that calls for an ontological shift away from the western ontology, towards an inclusive and holistic conceptualisation. Historiography that is anchored in de-colonial thinking of South Africa’s land governance helps us understand how and why – colonial/apartheid norms acrimoniously found their way into the post-apartheid order -- the post-apartheid institutions of modernity rest on the same hierarchies of identities, classification and pathologisation. The study concludes that, while the colonial/apartheid administration may be gone, it’s underlying power matrices continue -- i.e. capitalism/European/patriachal/white – in a manner which explains the continuities of South Africa’s spatial inequalities and the associated economic inequalities. The organising principle for land relations (including opportunities) continues to be underpinned by gender, race and class, in ways that expose the mythical dimensions of the 'post-apartheid' underbelly. While identifying the need for homogenisation and rationalistion of colonial, apartheid and post-apartheid institutions (on a national scale) that is insufficient for the transformation of the colonial situation of what is in essence a part of the global system, the study advocates for the ‘repurposing of land governance and administration’ – underpinned by de-colonial thinking. Repurposing is seen as political imaginary that would entail uncoupling thought processes and praxis from the colonial matrices of power. The study goes on to conclude that there is a definite role for Open Government Data in repurposing of land administration in the post-apartheid South Africa – as a necessary, though in and of it’s own it is an insufficient condition to achieve that ideal -- but presents an opportunity to enhance transdisciplinarity approaches and efficiencies in internal government functioning and evidence-based decision making and policy formulation processes. , Thesis (PhD) -- Faculty of Science, Geography, 2021
- Full Text:
Chave Chemutengure Vhiri Rengoro : Husarungano Nerwendo Rwengano Dzevashona
- Authors: Mabasa, Ignatius T
- Date: 2021
- Subjects: Ethnology -- Zimbabwe , Zimbabwe -- Folklore , Shona (African people) -- Folklore , Ethnoscience , Decolonization in literature , Decolonization -- Africa , Autoethnography , Chemutengure , Subaltern
- Language: Shona
- Type: text , Thesis , Doctoral , PHD
- Identifier: http://hdl.handle.net/10962/174198 , vital:42454 , http://doi.org/10.21504/10962/174198
- Description: Tsvakurudzo ino inyaya yangu sasarungano nemunyori weChiShona, asiwo iri nyaya yevanhu veChiShona. Inyaya yekurerwa kwandakaitwa nengano, ndikaona ngano dzakandirera dzichipinzwa muzvikoro, dzichisangana nechirungu, dzichifambidzana nechirungu, nekuzopedzisira dzazvara mimwe misambo yengano. Basa rino maonero angu ndichishandisa nzira yetsvakurudzo inonzi husarungano, kureva muono wasarungano. Izvi zvinoreva kududzira nekutsanangura, kufungisisa nekupenengura humhizha hunowanikwa mutsika nemagariro angu, sasarungano ari kupfuurira mberi nekuita ngano munyika yazara chirungu. Naizvozvo, ini ndini musoro wenyaya yandiri kutaura, asiwo ndirini zvakare muiti wetsvakurudzo. Ndichishandisa zvandakasangana nazvo, nezvandinofunga nekuona sasarungano – ndinodzokera kuchimbo chinotaura nyaya yevaShona pakapinda vachena munyika yeZimbabwe. Ndinotsanangura zvinoreva Chemutengure, uye nekukosha kwacho mukufambisa ruzivo, mashoko nekutsanangura hupenyu hwedu sevanhu vatema vakanga vakadzvanyiriwa. Chemutengure mafungiro, imhenenguro, iyambiro nehungwaru. Ndinotsanangura ruzivo rwevanhu vangu nekushanduka kwarwo kwakakonzerwa nechirungu. Ndinoita izvi ndichipenengura ngano, mabhuku, nziyo, mafungiro nezvimwe zvimutengure zvakatakura ngano. Otoetinogirafu iyo yandichapa zita rekuti husarungano imhando yekuvhiya uchiita tsvakurudzo, uye inowanikwa pakati pehumhizha hwekunyora nyaya nekupenengura zvine chekuita nehumhizha hwetsika nemagariro evanhu. Husarungano hunovhurira musiwo vanhu vanowanzovharirwa kunze netsvakurudzo dzinoitwa mumayunivhesiti dzine mitauro isiri yavo uyewo dzimwe nguva isinganzwisisike zviri nyn’ore. Husarungano hunoshandisa rondedzero nengano kuti zvinhu zvinosanganisira hukama nezvakasanganikwa nazvo nevanhu zvinzwisisike, panguva imwechete pachiumbwa hukama pakati penguva dzakare nazvino, hukama pakati pevanoita tsvakurudzo nevavari kuita tsvakurudzo pamusoro pavo, hukama pakati pevanyori nevaverengi, vanasarungano nevateereri vengano (Adams nevamwe, 2015). Tsvakurudzo ino haisi kuzopedza zvese zvinofanira kutaurwa pamusoro pengano, tsika nemagariro evanhu vatema, kunyorwa kwemabhuku nezvimwe zvakawanda zvainobata nekutarisa, asi riripo kuratidza simba nehupfumi huri muruzivo rwevaShona rwuri kurariswa muberere memba, chirungu chichirariswa mumba. Shanduko yandiri kutarisa mubasa rino inoda kuti isu vanhu vatema tisarambe tichiverengera kuti tirongeke nekuronga mafambiro nemararamiro achaita ruzivo rwedu munyika iri kukoshesa ruzivo, maitiro nezvinhu zvinogadzirwa nevarungu. Kana tikasaronga kuti tipembedze nekuwanisa ruzivo rwedu mukana, tichaita mufakose – kurasikirwa nezvedu, nekusakwana kana kunyatsonzwisisa zvevamwe zvatiri kukoshesa. Ruzivo rwandakashandisa mubasa rino rwunosanganisira zvakaitika kwandiri kubva pandakatanga kuziva ngano dzandakaudzwa nambuya vangu, kubatsirwa kwangu nengano kuchikoro, kuve munyori wemabhuku, nekuenda kwangu mhiri kwemakungwa sasarungano. Zvakarewo ndiri kutarisa ngano dzakaunganidzwa nekunyorwa nemamishenari, ngano dzakanyorwa kare muNative Afffairs Department Annual (NADA), ngano dzakaitwa senziyo, ngano dzakaitwa neLiterature Bureau, nengano dzandave kuita dzemanon-governmental organisations (NGO), panhepfenyuro, paTwitter nezvimwe zvimutengure zvakasiyana-siyana. Hupfumi huri mungano, mazano ekuri kuenda ngano dzedu, nezvinoreva chemutengure senzira yemafungiro zvinobuda mutsvakurudzo ino. Chitsauko 1 ndicho chinozama kutevedza nzira yekuita tsvakurudzo inozivikanwa, asi Chitsauko 2 inyunyuto inoburitsa mukundo une chirungu sekuunzwa kwachakaitwa naCecil John Rhodes. Chitsauko 3 chinotambanudza nekujekesa kukosha kwechimbo Chemutengure, uyewo nekuti sezano, chemutengure chinotibata sei nhasi uno. Chitsauko 4 chinoronda nzira dzakafamba nadzo ngano dzekunze dzichipinda matiri, uyewo nezvakaitwa nengano dzedu pamusoro peshanduko yakanga yauya. Chitsauko 5 chinopa mienzaniso yezviteshi zvakamira ngano dzevatema padzakabva mumisha dzichienda kuzvikoro kusvika dzazove muzvimwe zvimutengure zvakadziendesa kure nasarungano. Chitsauko 6 chinotarisa dambudziko rine chirungu muhupenyu hwevanhu vatema, nekukosha kwekudada nerudzi rwedu. Chitsauko 7 chinopeta basa chichipa mazano, chichiratidza kuti ngano hadzifanire kufa nekuti dzakagara dzine simba rekufambirana nenguva. , This research is my story as a Shona folklorist and creative writer, but it is also the story of the Shona people. It is a story of how I am “a child” of storytelling, and how the stories that raised me got appropriated and incorporated into the colonial school system where they converged and mixed with western forms of storytelling to create hybrids. As a storyteller I use autoethnography – which offers an insider’s perspective - to interpret and explain, to reflect and analyse the art of storytelling in my culture. The alienation of indigenous knowledge and cultural practices – specifically storytelling, is what necessitates the use of autoethnography for this study. Autoethnography is a qualitative research method of writing and storytelling where the researcher is the subject and the researcher's experiences are the data. I, being a Shona storyteller and creative writer, will systematically journey back and analyse personal experiences in order to make sense of the Shona people’s cultural experiences. The research process will see me running away from depending on other people’s records about my people’s cultural history. Instead, I traverse back in time to consult and extract a theory from the Shona song called Chemutengure from around 1890 that tells the story of British colonisation from the perspective of the colonised. I theorise and explain Chemutengure’s pedagogical and epistemological significance in critiquing the plight of Africans suffering contact-induced change. I apply the Chemutengure theory to folktales, books, songs, paradigms and other agents that played an active role in producing new forms of storytelling and worldviews. Autoethnography is a type of research method that blends engaging creative writing and analysis of cultural experiences. It opens doors of research to the subalterns who are usually shut out by research that is done in universities. “Rather than producing esoteric, jargon-laden texts, many auto-ethnographers recognize a need to speak also to nonacademic audiences,” (Adams et al, 2015: 42) employing narrative and story-telling to give meaning to identities, relationships, and experiences, and to create relationships between past and present, researchers and participants, writers and readers, tellers and audiences, (Adams et al, 2015:23). This research will not exhaust all that needs to be explored and said about Shona folktales, creativity and culture, or its literature and the many cultural aspects it looks at. Rather, it seeks to highlight, decolonize and deconstruct colonial mentalities, while emancipating the Shona worldview that has been put on leash by colonialism and western capitalistic tendencies. The study also looks at positive change that occurs when cultures inform one another, but without turning a blind eye to the lack of mutuality and how the logic of capitalism has left Africa hemorrhaging ideologically. Drawing from personal experiences when I listened to my grandmother’s stories, the study looks at the influence of folktales on my creative writing career. I reflect on my experiences as a Fulbright Scholar, as well as my Canadian experiences as storyteller and writer-in-residence at the University of Manitoba. Besides analysing stories written by missionaries in early Shona school readers, I also discuss folktales published in the Native Affairs Department Annual (NADA); the folktales performed as songs; the comic tales published by the Literature Bureau; tales developed for private institutions, government and non-governmental organisations; stories on radio, Twitter and many other forms. Besides giving the subaltern a voice, this research attempts to artistically demonstrate the power and versatility of the Shona folktale, as well as the genre’s potential for growth and development. Chapter 1 introduces the autoethngraphy method as well as what I hope to achieve through the methodology and style of writing. Chapter 2 is a conversation between a representative of the colonised and Cecil John Rhodes the imperialist. Besides pointing out imperialism’s damage to indigenous identities, the chapter discusses how Africa and Europe’s paradigms are diametrically conflicting. Chapter 3 introduces, explains and analyses the song/theory Chemutengure, and how it applies to the condition of the native in postcolonial Africa today. Chapter 4 tracks the trajectory of foreign tales in Zimbabwe, and how they influenced native folktales. The response of local tales is also critiqued. Chapter 5 looks at the milestones in the structural transformation of indigenous folktales, and how they were appropriated and hitched a ride in the wagon of change. Chapter 6 is a reflection on the impact of westernisation and globalisation in the lives of Africans, and how confused the native has become without his cultural anchor. Chapter 7 concludes by acknowledging the inevitability of change, and suggests how cultural practices and perspectives must respond to social change so as to remain relevant.
- Full Text:
- Authors: Mabasa, Ignatius T
- Date: 2021
- Subjects: Ethnology -- Zimbabwe , Zimbabwe -- Folklore , Shona (African people) -- Folklore , Ethnoscience , Decolonization in literature , Decolonization -- Africa , Autoethnography , Chemutengure , Subaltern
- Language: Shona
- Type: text , Thesis , Doctoral , PHD
- Identifier: http://hdl.handle.net/10962/174198 , vital:42454 , http://doi.org/10.21504/10962/174198
- Description: Tsvakurudzo ino inyaya yangu sasarungano nemunyori weChiShona, asiwo iri nyaya yevanhu veChiShona. Inyaya yekurerwa kwandakaitwa nengano, ndikaona ngano dzakandirera dzichipinzwa muzvikoro, dzichisangana nechirungu, dzichifambidzana nechirungu, nekuzopedzisira dzazvara mimwe misambo yengano. Basa rino maonero angu ndichishandisa nzira yetsvakurudzo inonzi husarungano, kureva muono wasarungano. Izvi zvinoreva kududzira nekutsanangura, kufungisisa nekupenengura humhizha hunowanikwa mutsika nemagariro angu, sasarungano ari kupfuurira mberi nekuita ngano munyika yazara chirungu. Naizvozvo, ini ndini musoro wenyaya yandiri kutaura, asiwo ndirini zvakare muiti wetsvakurudzo. Ndichishandisa zvandakasangana nazvo, nezvandinofunga nekuona sasarungano – ndinodzokera kuchimbo chinotaura nyaya yevaShona pakapinda vachena munyika yeZimbabwe. Ndinotsanangura zvinoreva Chemutengure, uye nekukosha kwacho mukufambisa ruzivo, mashoko nekutsanangura hupenyu hwedu sevanhu vatema vakanga vakadzvanyiriwa. Chemutengure mafungiro, imhenenguro, iyambiro nehungwaru. Ndinotsanangura ruzivo rwevanhu vangu nekushanduka kwarwo kwakakonzerwa nechirungu. Ndinoita izvi ndichipenengura ngano, mabhuku, nziyo, mafungiro nezvimwe zvimutengure zvakatakura ngano. Otoetinogirafu iyo yandichapa zita rekuti husarungano imhando yekuvhiya uchiita tsvakurudzo, uye inowanikwa pakati pehumhizha hwekunyora nyaya nekupenengura zvine chekuita nehumhizha hwetsika nemagariro evanhu. Husarungano hunovhurira musiwo vanhu vanowanzovharirwa kunze netsvakurudzo dzinoitwa mumayunivhesiti dzine mitauro isiri yavo uyewo dzimwe nguva isinganzwisisike zviri nyn’ore. Husarungano hunoshandisa rondedzero nengano kuti zvinhu zvinosanganisira hukama nezvakasanganikwa nazvo nevanhu zvinzwisisike, panguva imwechete pachiumbwa hukama pakati penguva dzakare nazvino, hukama pakati pevanoita tsvakurudzo nevavari kuita tsvakurudzo pamusoro pavo, hukama pakati pevanyori nevaverengi, vanasarungano nevateereri vengano (Adams nevamwe, 2015). Tsvakurudzo ino haisi kuzopedza zvese zvinofanira kutaurwa pamusoro pengano, tsika nemagariro evanhu vatema, kunyorwa kwemabhuku nezvimwe zvakawanda zvainobata nekutarisa, asi riripo kuratidza simba nehupfumi huri muruzivo rwevaShona rwuri kurariswa muberere memba, chirungu chichirariswa mumba. Shanduko yandiri kutarisa mubasa rino inoda kuti isu vanhu vatema tisarambe tichiverengera kuti tirongeke nekuronga mafambiro nemararamiro achaita ruzivo rwedu munyika iri kukoshesa ruzivo, maitiro nezvinhu zvinogadzirwa nevarungu. Kana tikasaronga kuti tipembedze nekuwanisa ruzivo rwedu mukana, tichaita mufakose – kurasikirwa nezvedu, nekusakwana kana kunyatsonzwisisa zvevamwe zvatiri kukoshesa. Ruzivo rwandakashandisa mubasa rino rwunosanganisira zvakaitika kwandiri kubva pandakatanga kuziva ngano dzandakaudzwa nambuya vangu, kubatsirwa kwangu nengano kuchikoro, kuve munyori wemabhuku, nekuenda kwangu mhiri kwemakungwa sasarungano. Zvakarewo ndiri kutarisa ngano dzakaunganidzwa nekunyorwa nemamishenari, ngano dzakanyorwa kare muNative Afffairs Department Annual (NADA), ngano dzakaitwa senziyo, ngano dzakaitwa neLiterature Bureau, nengano dzandave kuita dzemanon-governmental organisations (NGO), panhepfenyuro, paTwitter nezvimwe zvimutengure zvakasiyana-siyana. Hupfumi huri mungano, mazano ekuri kuenda ngano dzedu, nezvinoreva chemutengure senzira yemafungiro zvinobuda mutsvakurudzo ino. Chitsauko 1 ndicho chinozama kutevedza nzira yekuita tsvakurudzo inozivikanwa, asi Chitsauko 2 inyunyuto inoburitsa mukundo une chirungu sekuunzwa kwachakaitwa naCecil John Rhodes. Chitsauko 3 chinotambanudza nekujekesa kukosha kwechimbo Chemutengure, uyewo nekuti sezano, chemutengure chinotibata sei nhasi uno. Chitsauko 4 chinoronda nzira dzakafamba nadzo ngano dzekunze dzichipinda matiri, uyewo nezvakaitwa nengano dzedu pamusoro peshanduko yakanga yauya. Chitsauko 5 chinopa mienzaniso yezviteshi zvakamira ngano dzevatema padzakabva mumisha dzichienda kuzvikoro kusvika dzazove muzvimwe zvimutengure zvakadziendesa kure nasarungano. Chitsauko 6 chinotarisa dambudziko rine chirungu muhupenyu hwevanhu vatema, nekukosha kwekudada nerudzi rwedu. Chitsauko 7 chinopeta basa chichipa mazano, chichiratidza kuti ngano hadzifanire kufa nekuti dzakagara dzine simba rekufambirana nenguva. , This research is my story as a Shona folklorist and creative writer, but it is also the story of the Shona people. It is a story of how I am “a child” of storytelling, and how the stories that raised me got appropriated and incorporated into the colonial school system where they converged and mixed with western forms of storytelling to create hybrids. As a storyteller I use autoethnography – which offers an insider’s perspective - to interpret and explain, to reflect and analyse the art of storytelling in my culture. The alienation of indigenous knowledge and cultural practices – specifically storytelling, is what necessitates the use of autoethnography for this study. Autoethnography is a qualitative research method of writing and storytelling where the researcher is the subject and the researcher's experiences are the data. I, being a Shona storyteller and creative writer, will systematically journey back and analyse personal experiences in order to make sense of the Shona people’s cultural experiences. The research process will see me running away from depending on other people’s records about my people’s cultural history. Instead, I traverse back in time to consult and extract a theory from the Shona song called Chemutengure from around 1890 that tells the story of British colonisation from the perspective of the colonised. I theorise and explain Chemutengure’s pedagogical and epistemological significance in critiquing the plight of Africans suffering contact-induced change. I apply the Chemutengure theory to folktales, books, songs, paradigms and other agents that played an active role in producing new forms of storytelling and worldviews. Autoethnography is a type of research method that blends engaging creative writing and analysis of cultural experiences. It opens doors of research to the subalterns who are usually shut out by research that is done in universities. “Rather than producing esoteric, jargon-laden texts, many auto-ethnographers recognize a need to speak also to nonacademic audiences,” (Adams et al, 2015: 42) employing narrative and story-telling to give meaning to identities, relationships, and experiences, and to create relationships between past and present, researchers and participants, writers and readers, tellers and audiences, (Adams et al, 2015:23). This research will not exhaust all that needs to be explored and said about Shona folktales, creativity and culture, or its literature and the many cultural aspects it looks at. Rather, it seeks to highlight, decolonize and deconstruct colonial mentalities, while emancipating the Shona worldview that has been put on leash by colonialism and western capitalistic tendencies. The study also looks at positive change that occurs when cultures inform one another, but without turning a blind eye to the lack of mutuality and how the logic of capitalism has left Africa hemorrhaging ideologically. Drawing from personal experiences when I listened to my grandmother’s stories, the study looks at the influence of folktales on my creative writing career. I reflect on my experiences as a Fulbright Scholar, as well as my Canadian experiences as storyteller and writer-in-residence at the University of Manitoba. Besides analysing stories written by missionaries in early Shona school readers, I also discuss folktales published in the Native Affairs Department Annual (NADA); the folktales performed as songs; the comic tales published by the Literature Bureau; tales developed for private institutions, government and non-governmental organisations; stories on radio, Twitter and many other forms. Besides giving the subaltern a voice, this research attempts to artistically demonstrate the power and versatility of the Shona folktale, as well as the genre’s potential for growth and development. Chapter 1 introduces the autoethngraphy method as well as what I hope to achieve through the methodology and style of writing. Chapter 2 is a conversation between a representative of the colonised and Cecil John Rhodes the imperialist. Besides pointing out imperialism’s damage to indigenous identities, the chapter discusses how Africa and Europe’s paradigms are diametrically conflicting. Chapter 3 introduces, explains and analyses the song/theory Chemutengure, and how it applies to the condition of the native in postcolonial Africa today. Chapter 4 tracks the trajectory of foreign tales in Zimbabwe, and how they influenced native folktales. The response of local tales is also critiqued. Chapter 5 looks at the milestones in the structural transformation of indigenous folktales, and how they were appropriated and hitched a ride in the wagon of change. Chapter 6 is a reflection on the impact of westernisation and globalisation in the lives of Africans, and how confused the native has become without his cultural anchor. Chapter 7 concludes by acknowledging the inevitability of change, and suggests how cultural practices and perspectives must respond to social change so as to remain relevant.
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Coastal pH variability and the eco-physiological and behavioural response of a coastal fish species in light of future ocean acidification
- Authors: Edworthy, Carla
- Date: 2021
- Subjects: Ocean acidification , Diplodus capensis (Blacktail) , Diplodus -- South Africa -- Algoa Bay , Diplodus -- Metabolism , Diplodus -- Food , Diplodus -- Larvae , Marine ecology -- South Africa -- Algoa Bay , Carbon dioxide -- Physiological effect , Respiration -- Measurement
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/176793 , vital:42759 , 10.21504/10962/176793
- Description: Ocean acidification (OA) is a global phenomenon referring to a decrease in ocean pH and a perturbation of the seawater carbonate system due to ever-increasing atmospheric CO2 concentrations. In coastal environments, identifying the impacts of OA is complex due to the multiple contributors to pH variability by coastal processes, such as freshwater inflow, upwelling, hydrodynamic processes, and biological activity. The aim of this PhD study was to quantify the local processes occurring in a temperate coastal embayment, Algoa Bay in South Africa, that contribute to pH and carbonate chemistry variability over time (monthly and 24-hour) and space (~10 km) and examine how this variability impacts a local fish species, Diplodus capensis, also commonly known as ‘blacktail’. Algoa Bay, known for its complex oceanography, is an interesting location in which to quantify carbonate chemistry variability. To assess this variability, monitoring sites were selected to coincide with the Algoa Bay Sentinel Site long-term ecological research (LTER) and continuous monitoring (CMP) programmes. The average pH at offshore sites in the bay was 8.03 ± 0.07 and at inshore sites was 8.04 ± 0.15. High pH variability (~0.55–0.61 pH units) was recorded at both offshore (>10 m depth) and inshore sites (intertidal surf zones). Many sites in the bay, especially the atypical site at Cape Recife, exhibit higher than the average pH levels (>8.04), suggesting that pH variability may be biologically driven. This is further evidenced by high diurnal variability in pH (~0.55 pH units). Although the specific drivers of the high pH variability in Algoa Bay could not be identified, baseline carbonate chemistry conditions were identified, which is necessary information to design and interpret biological experiments. Long-term, continuous monitoring is required to improve understanding of the drivers of pH variability in understudied coastal regions, like Algoa Bay. A local fisheries species, D. capensis, was selected as a model species to assess the impacts of future OA scenarios in Algoa Bay. It was hypothesized that this temperate, coastally distributed species would be adapted to naturally variable pH conditions and thus show some tolerance to low pH, considering that they are exposed to minimum pH levels of 7.77 and fluctuations of up to 0.55 pH units. Laboratory perturbation experiments were used to expose early postflexion stage of D. capensis to a range of pH treatments that were selected based on the measured local variability (~8.0–7.7 pH), as well as future projected OA scenarios (7.6–7.2 pH). Physiological responses were estimated using intermittent flow respirometry by quantifying routine and active metabolic rates as well as relative aerobic scope at each pH treatment. The behavioural responses of the larvae were also assessed at each pH treatment, as activity levels, by measuring swimming distance and speed in video-recording experiments, as well as feeding rates. D. capensis had sufficient physiological capacity to maintain metabolic performance at pH levels as low as 7.27, as evidenced by no changes in any of the measured metabolic rates (routine metabolic rate, active metabolic rate, and relative aerobic scope) after exposure to the range of pH treatments (8.02–7.27). Feeding rates of D. capensis were similarly unaffected by pH treatment. However, it appears that subtle increases in activity level (measured by swimming distance and swimming speed experiments) occur with a decrease in pH. These changes in activity level were a consequence of a change in behaviour rather than metabolic constraints. This study concludes, however, that based on the parameters measured, there is no evidence for survival or fitness related consequences of near future OA on D. capensis. OA research is still in its infancy in South Africa, and the potential impacts of OA to local marine resources has not yet been considered in local policy and resource management strategies. Integrating field monitoring and laboratory perturbation experiments is emerging as best practice in OA research. This is the first known study on the temperate south coast of South Africa to quantify local pH variability and to use this information to evaluate the biological response of a local species using relevant local OA scenarios as treatment levels for current and near future conditions. Research on local conditions in situ and the potential impacts of future OA scenarios on socio-economically valuable species, following the model developed in this study, is necessary to provide national policy makers with relevant scientific data to inform climate change management policies for local resources.
- Full Text:
- Authors: Edworthy, Carla
- Date: 2021
- Subjects: Ocean acidification , Diplodus capensis (Blacktail) , Diplodus -- South Africa -- Algoa Bay , Diplodus -- Metabolism , Diplodus -- Food , Diplodus -- Larvae , Marine ecology -- South Africa -- Algoa Bay , Carbon dioxide -- Physiological effect , Respiration -- Measurement
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/176793 , vital:42759 , 10.21504/10962/176793
- Description: Ocean acidification (OA) is a global phenomenon referring to a decrease in ocean pH and a perturbation of the seawater carbonate system due to ever-increasing atmospheric CO2 concentrations. In coastal environments, identifying the impacts of OA is complex due to the multiple contributors to pH variability by coastal processes, such as freshwater inflow, upwelling, hydrodynamic processes, and biological activity. The aim of this PhD study was to quantify the local processes occurring in a temperate coastal embayment, Algoa Bay in South Africa, that contribute to pH and carbonate chemistry variability over time (monthly and 24-hour) and space (~10 km) and examine how this variability impacts a local fish species, Diplodus capensis, also commonly known as ‘blacktail’. Algoa Bay, known for its complex oceanography, is an interesting location in which to quantify carbonate chemistry variability. To assess this variability, monitoring sites were selected to coincide with the Algoa Bay Sentinel Site long-term ecological research (LTER) and continuous monitoring (CMP) programmes. The average pH at offshore sites in the bay was 8.03 ± 0.07 and at inshore sites was 8.04 ± 0.15. High pH variability (~0.55–0.61 pH units) was recorded at both offshore (>10 m depth) and inshore sites (intertidal surf zones). Many sites in the bay, especially the atypical site at Cape Recife, exhibit higher than the average pH levels (>8.04), suggesting that pH variability may be biologically driven. This is further evidenced by high diurnal variability in pH (~0.55 pH units). Although the specific drivers of the high pH variability in Algoa Bay could not be identified, baseline carbonate chemistry conditions were identified, which is necessary information to design and interpret biological experiments. Long-term, continuous monitoring is required to improve understanding of the drivers of pH variability in understudied coastal regions, like Algoa Bay. A local fisheries species, D. capensis, was selected as a model species to assess the impacts of future OA scenarios in Algoa Bay. It was hypothesized that this temperate, coastally distributed species would be adapted to naturally variable pH conditions and thus show some tolerance to low pH, considering that they are exposed to minimum pH levels of 7.77 and fluctuations of up to 0.55 pH units. Laboratory perturbation experiments were used to expose early postflexion stage of D. capensis to a range of pH treatments that were selected based on the measured local variability (~8.0–7.7 pH), as well as future projected OA scenarios (7.6–7.2 pH). Physiological responses were estimated using intermittent flow respirometry by quantifying routine and active metabolic rates as well as relative aerobic scope at each pH treatment. The behavioural responses of the larvae were also assessed at each pH treatment, as activity levels, by measuring swimming distance and speed in video-recording experiments, as well as feeding rates. D. capensis had sufficient physiological capacity to maintain metabolic performance at pH levels as low as 7.27, as evidenced by no changes in any of the measured metabolic rates (routine metabolic rate, active metabolic rate, and relative aerobic scope) after exposure to the range of pH treatments (8.02–7.27). Feeding rates of D. capensis were similarly unaffected by pH treatment. However, it appears that subtle increases in activity level (measured by swimming distance and swimming speed experiments) occur with a decrease in pH. These changes in activity level were a consequence of a change in behaviour rather than metabolic constraints. This study concludes, however, that based on the parameters measured, there is no evidence for survival or fitness related consequences of near future OA on D. capensis. OA research is still in its infancy in South Africa, and the potential impacts of OA to local marine resources has not yet been considered in local policy and resource management strategies. Integrating field monitoring and laboratory perturbation experiments is emerging as best practice in OA research. This is the first known study on the temperate south coast of South Africa to quantify local pH variability and to use this information to evaluate the biological response of a local species using relevant local OA scenarios as treatment levels for current and near future conditions. Research on local conditions in situ and the potential impacts of future OA scenarios on socio-economically valuable species, following the model developed in this study, is necessary to provide national policy makers with relevant scientific data to inform climate change management policies for local resources.
- Full Text:
Defended subjectivity in service-learning:a psychosocial analysis of students’ talk about service-learning in psychology
- Authors: Haselau, Tracey Laura
- Date: 2021
- Subjects: Service learning -- Case studies -- South Africa -- Makhanda , Rhodes University -- Students -- Attitudes , Psychology students -- Attitudes -- South Africa -- Makhanda
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/170810 , vital:41962 , 10.21504/10962/170810
- Description: The purpose of this qualitative study was to analyse students’ talk about their service-learning experiences in psychology, in South Africa, from a psychosocial perspective. The research aims to identify dominant and subjugated discourses about service-learning in psychology, and to explore why students invest in particular discourses over others. Furthermore, the research aims to explore the intersubjective contexts that mediate students’ talk about their service-learning and their emotional investments in the discourses employed in their talk, drawing on the concept of mentalization. Eight psychology students were interviewed toward the end of their participation in a service-learning psychology honours course. Transcripts from the interviews as well as entries from students’ reflective journals were analysed using a psychosocial methodology. The key findings from this research point to the ways in which students oscillate between employing two competing sets of discourses about their service learning. At times, students drew on what I have referred to as a ‘discourse of rapture’, characterised by fascination with the ‘other’ and the maintenance of power imbalances. This discourse draws on a liberal traditional discourse of learning and a charity discourse of service-learning. In other parts of their talk, students draw on what I have called a ‘discourse of ruptura’, characterised by an inward curiosity about the outward fascination with the ‘other’. This discourse draws on constructivist accounts of service-learning. Findings suggest that students’ emotional investments in discourses of service-learning are mediated by defensive positions caused by the anxieties incurred in service-learning contexts. An important consideration to take forward from this research is the way in which anxieties in service-learning experiences may be contained (or not), and to be aware of the problematic outcomes that may arise from not containing anxieties, such as the perpetuation of prejudicial attitudes and othering. The intersectionality of ‘race’ and disability in the specific service-learning programme under investigation in this study is an important consideration in implementing careful supervision of programmes such as this one, so that students’ rapture with the ‘other’ is not compounded and reinforced by the service-learning experience.
- Full Text:
- Authors: Haselau, Tracey Laura
- Date: 2021
- Subjects: Service learning -- Case studies -- South Africa -- Makhanda , Rhodes University -- Students -- Attitudes , Psychology students -- Attitudes -- South Africa -- Makhanda
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/170810 , vital:41962 , 10.21504/10962/170810
- Description: The purpose of this qualitative study was to analyse students’ talk about their service-learning experiences in psychology, in South Africa, from a psychosocial perspective. The research aims to identify dominant and subjugated discourses about service-learning in psychology, and to explore why students invest in particular discourses over others. Furthermore, the research aims to explore the intersubjective contexts that mediate students’ talk about their service-learning and their emotional investments in the discourses employed in their talk, drawing on the concept of mentalization. Eight psychology students were interviewed toward the end of their participation in a service-learning psychology honours course. Transcripts from the interviews as well as entries from students’ reflective journals were analysed using a psychosocial methodology. The key findings from this research point to the ways in which students oscillate between employing two competing sets of discourses about their service learning. At times, students drew on what I have referred to as a ‘discourse of rapture’, characterised by fascination with the ‘other’ and the maintenance of power imbalances. This discourse draws on a liberal traditional discourse of learning and a charity discourse of service-learning. In other parts of their talk, students draw on what I have called a ‘discourse of ruptura’, characterised by an inward curiosity about the outward fascination with the ‘other’. This discourse draws on constructivist accounts of service-learning. Findings suggest that students’ emotional investments in discourses of service-learning are mediated by defensive positions caused by the anxieties incurred in service-learning contexts. An important consideration to take forward from this research is the way in which anxieties in service-learning experiences may be contained (or not), and to be aware of the problematic outcomes that may arise from not containing anxieties, such as the perpetuation of prejudicial attitudes and othering. The intersectionality of ‘race’ and disability in the specific service-learning programme under investigation in this study is an important consideration in implementing careful supervision of programmes such as this one, so that students’ rapture with the ‘other’ is not compounded and reinforced by the service-learning experience.
- Full Text:
Design patterns and software techniques for large-scale, open and reproducible data reduction
- Authors: Molenaar, Gijs Jan
- Date: 2021
- Subjects: Radio astronomy -- Data processing , Radio astronomy -- Data processing -- Software , Radio astronomy -- South Africa , ASTRODECONV2019 dataset , Radio telescopes -- South Africa , KERN (omputer software)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172169 , vital:42172 , 10.21504/10962/172169
- Description: The preparation for the construction of the Square Kilometre Array, and the introduction of its operational precursors, such as LOFAR and MeerKAT, mark the beginning of an exciting era for astronomy. Impressive new data containing valuable science just waiting for discovery is already being generated, and these devices will produce far more data than has ever been collected before. However, with every new data instrument, the data rates grow to unprecedented quantities of data, requiring novel new data-processing tools. In addition, creating science grade data from the raw data still requires significant expert knowledge for processing this data. The software used is often developed by a scientist who lacks proper training in software development skills, resulting in the software not progressing beyond a prototype stage in quality. In the first chapter, we explore various organisational and technical approaches to address these issues by providing a historical overview of the development of radioastronomy pipelines since the inception of the field in the 1940s. In that, the steps required to create a radio image are investigated. We used the lessons-learned to identify patterns in the challenges experienced, and the solutions created to address these over the years. The second chapter describes the mathematical foundations that are essential for radio imaging. In the third chapter, we discuss the production of the KERN Linux distribution, which is a set of software packages containing most radio astronomy software currently in use. Considerable effort was put into making sure that the contained software installs appropriately, all items next to one other on the same system. Where required and possible, bugs and portability fixes were solved and reported with the upstream maintainers. The KERN project also has a website, and issue tracker, where users can report bugs and maintainers can coordinate the packaging effort and new releases. The software packages can be used inside Docker and Singularity containers, enabling the installation of these packages on a wide variety of platforms. In the fourth and fifth chapters, we discuss methods and frameworks for combining the available data reduction tools into recomposable pipelines and introduce the Kliko specification and software. This framework was created to enable end-user astronomers to chain and containerise operations of software in KERN packages. Next, we discuss the Common Workflow Language (CommonWL), a similar but more advanced and mature pipeline framework invented by bio-informatics scientists. CommonWL is supported by a wide range of tools already; among other schedulers, visualisers and editors. Consequently, when a pipeline is made with CommonWL, it can be deployed and manipulated with a wide range of tools. In the final chapter, we attempt something unconventional, applying a generative adversarial network based on deep learning techniques to perform the task of sky brightness reconstruction. Since deep learning methods often require a large number of training samples, we constructed a CommonWL simulation pipeline for creating dirty images and corresponding sky models. This simulated dataset has been made publicly available as the ASTRODECONV2019 dataset. It is shown that this method is useful to perform the restoration and matches the performance of a single clean cycle. In addition, we incorporated domain knowledge by adding the point spread function to the network and by utilising a custom loss function during training. Although it was not possible to improve the cleaning performance of commonly used existing tools, the computational time performance of the approach looks very promising. We suggest that a smaller scope should be the starting point for further studies and optimising of the training of the neural network could produce the desired results.
- Full Text:
- Authors: Molenaar, Gijs Jan
- Date: 2021
- Subjects: Radio astronomy -- Data processing , Radio astronomy -- Data processing -- Software , Radio astronomy -- South Africa , ASTRODECONV2019 dataset , Radio telescopes -- South Africa , KERN (omputer software)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172169 , vital:42172 , 10.21504/10962/172169
- Description: The preparation for the construction of the Square Kilometre Array, and the introduction of its operational precursors, such as LOFAR and MeerKAT, mark the beginning of an exciting era for astronomy. Impressive new data containing valuable science just waiting for discovery is already being generated, and these devices will produce far more data than has ever been collected before. However, with every new data instrument, the data rates grow to unprecedented quantities of data, requiring novel new data-processing tools. In addition, creating science grade data from the raw data still requires significant expert knowledge for processing this data. The software used is often developed by a scientist who lacks proper training in software development skills, resulting in the software not progressing beyond a prototype stage in quality. In the first chapter, we explore various organisational and technical approaches to address these issues by providing a historical overview of the development of radioastronomy pipelines since the inception of the field in the 1940s. In that, the steps required to create a radio image are investigated. We used the lessons-learned to identify patterns in the challenges experienced, and the solutions created to address these over the years. The second chapter describes the mathematical foundations that are essential for radio imaging. In the third chapter, we discuss the production of the KERN Linux distribution, which is a set of software packages containing most radio astronomy software currently in use. Considerable effort was put into making sure that the contained software installs appropriately, all items next to one other on the same system. Where required and possible, bugs and portability fixes were solved and reported with the upstream maintainers. The KERN project also has a website, and issue tracker, where users can report bugs and maintainers can coordinate the packaging effort and new releases. The software packages can be used inside Docker and Singularity containers, enabling the installation of these packages on a wide variety of platforms. In the fourth and fifth chapters, we discuss methods and frameworks for combining the available data reduction tools into recomposable pipelines and introduce the Kliko specification and software. This framework was created to enable end-user astronomers to chain and containerise operations of software in KERN packages. Next, we discuss the Common Workflow Language (CommonWL), a similar but more advanced and mature pipeline framework invented by bio-informatics scientists. CommonWL is supported by a wide range of tools already; among other schedulers, visualisers and editors. Consequently, when a pipeline is made with CommonWL, it can be deployed and manipulated with a wide range of tools. In the final chapter, we attempt something unconventional, applying a generative adversarial network based on deep learning techniques to perform the task of sky brightness reconstruction. Since deep learning methods often require a large number of training samples, we constructed a CommonWL simulation pipeline for creating dirty images and corresponding sky models. This simulated dataset has been made publicly available as the ASTRODECONV2019 dataset. It is shown that this method is useful to perform the restoration and matches the performance of a single clean cycle. In addition, we incorporated domain knowledge by adding the point spread function to the network and by utilising a custom loss function during training. Although it was not possible to improve the cleaning performance of commonly used existing tools, the computational time performance of the approach looks very promising. We suggest that a smaller scope should be the starting point for further studies and optimising of the training of the neural network could produce the desired results.
- Full Text:
Elucidating Tuta absoluta (Meyrick) invasion and enhancing its management in Eastern Africa : spread, socio-ecological impacts, and potential of a newly imported larval parasitoid for classical biological control Eastern in Africa
- Aigbedion-Atalor, Pascal Osabhahiemen
- Authors: Aigbedion-Atalor, Pascal Osabhahiemen
- Date: 2021
- Subjects: Tuta absoluta -- Biological control , Tomatoes -- Diseases and pests -- Africa, East , Braconidae , Gelechiidae -- Biological control -- Africa, East , Insects as biological pest control agents -- Africa, East
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/170421 , vital:41920 , 10.21504/10962/170421
- Description: Agriculture is a fundamental source of sustainable livelihoods in sub-Saharan Africa and millions of people in the region rely solely on small-scale farming for their food security. However, the impacts of invasive alien species (IAS) on crop production are serious, and there is no sign of this abating. Among the recent IAS that have invaded Africa in the last decade, the South American tomato pinworm Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) has been one of the most damaging. Following its first record in the Maghreb region of Africa in 2008, T. absoluta rapidly spread throughout Africa with substantial impacts on tomato production, often causing 100% yield loss. Management options adopted against T. absoluta by tomato growers in Africa have been based on the use of synthetic insecticides. While chemical insecticide applications are an important component of an integrated pest management programme, misuse and over-reliance often exacerbates the impacts of T. absolutadue to the development of resistance to commonly used active substances, increasing the fitness of the pest. This thesis sought to understand the socio-economic impacts of the spread of T. absoluta in Eastern Africa and provide effective sustainable pest management strategies to reduce its impacts below economic thresholds. Mapping surveys of Tabsoluta were conducted in 226 tomato agro-ecosystems across four eastern countries (Kenya, Sudan, Tanzania, and Uganda) Eastern Africa from 2016 to 2018 to determine the spatiotemporal distribution of the pest. The impacts of T. absoluta on the livelihoods of tomato growers were also assessed. Here, 200 tomato growers in Kenya were interviewed using a semi-structured questionnaire. Although T. absoluta, a recent invader, was distributed at high infestation levels throughout the subregion (all four countries) and was considered as the most damaging invasive alien species of agriculturally sustainable livelihoods. The arrival of T. absoluta in the subregion has resulted in livelihood losses and increased the cost of tomato production and price of the fruit, and the frequency of pesticide applications. The impact of this pest and the and the absence of effective indigenous natural enemies of the pest in Eastern Africa, was the rationale for the importation of a larval parasitoid, Dolichogenidea gelechiidivoris Marsh Syn.: Apanteles gelechiidivoris Marsh) (Hymenoptera: Braconidae), of T. absoluta from Peru into the quarantine facility of the International Centre of Insect Physiology and ecologyz(icipe), in Kenya. Pre-release assessments on the parasitzation potential of D. gelechiidivoris, encompassing host larval preference and the host suitability, and its reproductive strategy, for classical biological control of T. absoluta in Africa were conducted. Dolichogenidea gelechiidivoris females preferentially oviposited in early (1st and 2nd) larval instars of T. absoluta but parasitized and completed development in all four instars of the host. Host instar did not affect D. gelechiidivoris sex-ratio but females reared on the first instar had significantly fewer eggs than when reared in late larval instars (3rd and 4th). Females of the parasitoid emerged with a high mature egg load which peaked 2 d post-eclosion. The females of D. gelechiidivoris survived 8.51±0.65 d and produced 103±8 offspring per female at 26±4°C (range: 24 to 29°C) and 50–70% relative humidity (RH) in the presence of males and fed honey-water (80% honey). Increasing maternal age decreased the proportion of female offspring. Under the aforementioned laboratory conditions, the Gross and Net reproductive rates were 72 and 39.5 respectively, while the mean generation time was 20 d. The estimated intrinsic rate of natural increase was 0.18. These findings indicate that D. gelechiidivorisis a potential biological control agent of T. absoluta and should be considered for augmentative/inundative release in Kenya and across Africa following host specificity testing and risk assessments. The nature of the interaction between D. gelechidivoris and the predatory mirid bug Nesidiocoris tenuis(Reuter) (Hemiptera: Miridae), an important and widespread natural enemy of T. absoluta in Africa was evaluated because N. tenuis, although being a voracious predator of T. absoluta eggs, it can also prey on the early host larval instars (1st and 2nd) which are the preferred oviposition host stages of D. gelechiidivoris. Here, the impact of N. tenuis feeding on T. absoluta and the effects on D. gelechiidivoris performance was tested. Regardless of the order of introductions (i.e. the sequence of combination with D. gelechiidivoris) and densities (i.e. number of N. tenuis combined with D. gelechiidivoris), there was no intraguild predation by N. tenuis on D. gelechiidivorisas there was little host larval feeding behaviour. Also, the presence of N. tenuis did not affect the oviposition performance of D. gelechiidivoris. Further investigations revealed that the combined efficacy of N. tenuis and D. gelechiidivorison T. absoluta population was significantly higher than either natural enemy alone, thus contributes to the data supporting the release of D. gelechiidivoris in Africa. In concluding, integrating D. gelechiidivoris and N. tenuis in the management of T. absolut could potentially reduce yield losses in tomato in Eastern Africa where the socio-economic impacts of the pest are very serious.
- Full Text:
- Authors: Aigbedion-Atalor, Pascal Osabhahiemen
- Date: 2021
- Subjects: Tuta absoluta -- Biological control , Tomatoes -- Diseases and pests -- Africa, East , Braconidae , Gelechiidae -- Biological control -- Africa, East , Insects as biological pest control agents -- Africa, East
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/170421 , vital:41920 , 10.21504/10962/170421
- Description: Agriculture is a fundamental source of sustainable livelihoods in sub-Saharan Africa and millions of people in the region rely solely on small-scale farming for their food security. However, the impacts of invasive alien species (IAS) on crop production are serious, and there is no sign of this abating. Among the recent IAS that have invaded Africa in the last decade, the South American tomato pinworm Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) has been one of the most damaging. Following its first record in the Maghreb region of Africa in 2008, T. absoluta rapidly spread throughout Africa with substantial impacts on tomato production, often causing 100% yield loss. Management options adopted against T. absoluta by tomato growers in Africa have been based on the use of synthetic insecticides. While chemical insecticide applications are an important component of an integrated pest management programme, misuse and over-reliance often exacerbates the impacts of T. absolutadue to the development of resistance to commonly used active substances, increasing the fitness of the pest. This thesis sought to understand the socio-economic impacts of the spread of T. absoluta in Eastern Africa and provide effective sustainable pest management strategies to reduce its impacts below economic thresholds. Mapping surveys of Tabsoluta were conducted in 226 tomato agro-ecosystems across four eastern countries (Kenya, Sudan, Tanzania, and Uganda) Eastern Africa from 2016 to 2018 to determine the spatiotemporal distribution of the pest. The impacts of T. absoluta on the livelihoods of tomato growers were also assessed. Here, 200 tomato growers in Kenya were interviewed using a semi-structured questionnaire. Although T. absoluta, a recent invader, was distributed at high infestation levels throughout the subregion (all four countries) and was considered as the most damaging invasive alien species of agriculturally sustainable livelihoods. The arrival of T. absoluta in the subregion has resulted in livelihood losses and increased the cost of tomato production and price of the fruit, and the frequency of pesticide applications. The impact of this pest and the and the absence of effective indigenous natural enemies of the pest in Eastern Africa, was the rationale for the importation of a larval parasitoid, Dolichogenidea gelechiidivoris Marsh Syn.: Apanteles gelechiidivoris Marsh) (Hymenoptera: Braconidae), of T. absoluta from Peru into the quarantine facility of the International Centre of Insect Physiology and ecologyz(icipe), in Kenya. Pre-release assessments on the parasitzation potential of D. gelechiidivoris, encompassing host larval preference and the host suitability, and its reproductive strategy, for classical biological control of T. absoluta in Africa were conducted. Dolichogenidea gelechiidivoris females preferentially oviposited in early (1st and 2nd) larval instars of T. absoluta but parasitized and completed development in all four instars of the host. Host instar did not affect D. gelechiidivoris sex-ratio but females reared on the first instar had significantly fewer eggs than when reared in late larval instars (3rd and 4th). Females of the parasitoid emerged with a high mature egg load which peaked 2 d post-eclosion. The females of D. gelechiidivoris survived 8.51±0.65 d and produced 103±8 offspring per female at 26±4°C (range: 24 to 29°C) and 50–70% relative humidity (RH) in the presence of males and fed honey-water (80% honey). Increasing maternal age decreased the proportion of female offspring. Under the aforementioned laboratory conditions, the Gross and Net reproductive rates were 72 and 39.5 respectively, while the mean generation time was 20 d. The estimated intrinsic rate of natural increase was 0.18. These findings indicate that D. gelechiidivorisis a potential biological control agent of T. absoluta and should be considered for augmentative/inundative release in Kenya and across Africa following host specificity testing and risk assessments. The nature of the interaction between D. gelechidivoris and the predatory mirid bug Nesidiocoris tenuis(Reuter) (Hemiptera: Miridae), an important and widespread natural enemy of T. absoluta in Africa was evaluated because N. tenuis, although being a voracious predator of T. absoluta eggs, it can also prey on the early host larval instars (1st and 2nd) which are the preferred oviposition host stages of D. gelechiidivoris. Here, the impact of N. tenuis feeding on T. absoluta and the effects on D. gelechiidivoris performance was tested. Regardless of the order of introductions (i.e. the sequence of combination with D. gelechiidivoris) and densities (i.e. number of N. tenuis combined with D. gelechiidivoris), there was no intraguild predation by N. tenuis on D. gelechiidivorisas there was little host larval feeding behaviour. Also, the presence of N. tenuis did not affect the oviposition performance of D. gelechiidivoris. Further investigations revealed that the combined efficacy of N. tenuis and D. gelechiidivorison T. absoluta population was significantly higher than either natural enemy alone, thus contributes to the data supporting the release of D. gelechiidivoris in Africa. In concluding, integrating D. gelechiidivoris and N. tenuis in the management of T. absolut could potentially reduce yield losses in tomato in Eastern Africa where the socio-economic impacts of the pest are very serious.
- Full Text:
Evaluation of metallophthalocyanine functionalized photocatalytic asymmetric polymer membranes for pollution control and antimicrobial activity
- Mafukidze, Donovan Musizvinoda Chidyamurimi
- Authors: Mafukidze, Donovan Musizvinoda Chidyamurimi
- Date: 2021
- Subjects: Photosensitizing compounds , Water -- Purification -- Photocatalysis , Phthalocyanines , Polymeric membranes , Porphyrins
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/171357 , vital:42052 , 10.21504/10962/171357
- Description: The conceptualisation of photosensitizing water treatment polymer membranes using phthalocyanine based photosensitizers is reported in this thesis. The key to successful preparation of stable photoactive polymer membranes was established as the covalent anchorage of the photosensitizer to a polymer, which was proven by singlet oxygen generation by the membranes without photosensitizer deterioration. Despite this limitation, the covalent linkage-incapable unsubstituted zinc (II) phthalocyanine (complex 2) was applied as a nanoconjugate of graphene quantum dots (2π(GQDs)). 2π(GQDs) was formed through π-π stacking, and was then covalently anchored, as a proof of concept. This concept was also applied to 2-(4-carboxyphenoxy) phthalocyaninato zinc (II) (complex 3) which is capable of covalent linkage but proved to deteriorate the efficiency of singlet oxygen formation with comparison to the covalent conjugates. Singlet oxygen generation by functionalized polymer membranes rendered them photocatalytic in the degradation of organic pollutants and microorganisms in water. Organic pollutant degradation capability was exemplified by 2π(GQDs) and a porphyrin-phthalocyanine heterodyad (complex 10) functionalized membranes (2π(GQDs)-memb and 10-memb respectively), where a MPc loading of approximately 0.139 μmol MPc/g of membrane was able to achieve a 4-chlorophenol degradation rate of 3.77 × 10−6 mol L−1 min−1 in a second order reaction with an initial 4-chlorophenol concentration of 3.24 × 10−4 mol L−1 for 2π(GQDs)-memb as an example. Antibacterial studies against S.aureus using a quaternized MPc and conjugates of silver triangular nanoprisms with zinc (II) and indium (III) MPcs showed note-worthy improvements in photodynamic antimicrobial chemotherapy (PACT) activity in comparison to the unquaternized MPc precursor, and the free zinc and indium MPcs respectively. Functionalization of polymer membranes with these higher activity photosensitizers translated to the formation of potentially superior biological fouling resistant membranes. The use of porphyrin-phthalocyanine polynuclei arrays (complex 10) in polymer membrane functionalization resulted in the use of a wider wavelength range (white light). The findings from this work as a whole, thus presents the potential applicability of phthalocyanine functionalized polymer membranes in water treatment technology.
- Full Text:
- Authors: Mafukidze, Donovan Musizvinoda Chidyamurimi
- Date: 2021
- Subjects: Photosensitizing compounds , Water -- Purification -- Photocatalysis , Phthalocyanines , Polymeric membranes , Porphyrins
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/171357 , vital:42052 , 10.21504/10962/171357
- Description: The conceptualisation of photosensitizing water treatment polymer membranes using phthalocyanine based photosensitizers is reported in this thesis. The key to successful preparation of stable photoactive polymer membranes was established as the covalent anchorage of the photosensitizer to a polymer, which was proven by singlet oxygen generation by the membranes without photosensitizer deterioration. Despite this limitation, the covalent linkage-incapable unsubstituted zinc (II) phthalocyanine (complex 2) was applied as a nanoconjugate of graphene quantum dots (2π(GQDs)). 2π(GQDs) was formed through π-π stacking, and was then covalently anchored, as a proof of concept. This concept was also applied to 2-(4-carboxyphenoxy) phthalocyaninato zinc (II) (complex 3) which is capable of covalent linkage but proved to deteriorate the efficiency of singlet oxygen formation with comparison to the covalent conjugates. Singlet oxygen generation by functionalized polymer membranes rendered them photocatalytic in the degradation of organic pollutants and microorganisms in water. Organic pollutant degradation capability was exemplified by 2π(GQDs) and a porphyrin-phthalocyanine heterodyad (complex 10) functionalized membranes (2π(GQDs)-memb and 10-memb respectively), where a MPc loading of approximately 0.139 μmol MPc/g of membrane was able to achieve a 4-chlorophenol degradation rate of 3.77 × 10−6 mol L−1 min−1 in a second order reaction with an initial 4-chlorophenol concentration of 3.24 × 10−4 mol L−1 for 2π(GQDs)-memb as an example. Antibacterial studies against S.aureus using a quaternized MPc and conjugates of silver triangular nanoprisms with zinc (II) and indium (III) MPcs showed note-worthy improvements in photodynamic antimicrobial chemotherapy (PACT) activity in comparison to the unquaternized MPc precursor, and the free zinc and indium MPcs respectively. Functionalization of polymer membranes with these higher activity photosensitizers translated to the formation of potentially superior biological fouling resistant membranes. The use of porphyrin-phthalocyanine polynuclei arrays (complex 10) in polymer membrane functionalization resulted in the use of a wider wavelength range (white light). The findings from this work as a whole, thus presents the potential applicability of phthalocyanine functionalized polymer membranes in water treatment technology.
- Full Text:
How art-as-therapy supports participants with a diagnosis of schizophrenia : a phenomenological investigation
- Authors: Mitchell, Julia L G
- Date: 2021
- Subjects: Schizophrenia -- Treatment , Schizophrenia -- Treatment -- South Africa -- Case studies , Art Therapy , Art Therapy -- South Africa -- Case studies , Stormberg Hospital (Eastern Cape, South Africa)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172157 , vital:42171 , 10.21504/10962/172157
- Description: Although art therapy is recommended in management programmes for individuals with a diagnosis of schizophrenia, calls have been made for more detailed explanations as to how artmaking is working. This study responds to those calls by considering the artmaking experiences of 15 mental health users with a diagnosis of schizophrenia, resident at a forensic, mental health facility in South Africa. A phenomenological approach was chosen because of its focus on lived experiences, suited to explore the embodied and pre-reflective experience of studio-based artmaking. Dialogical and narrative understandings were subsequently incorporated to account for more reflective aspects of the artmaking experience. Two main participant descriptions of artmaking, centring on feeling at home and on doing something meaningful, guided the phenomenological lifeworld method in analysing the data (interviews, artworks and field observations in art groups and exhibitions), along selected dimensions of lived experience, namely embodiment, temporality, spatiality, sociality and selfhood. These findings lend support to new phenomenological research which suggests that artmaking intersects with disrupted abilities for perceptual engagement underlying manifestations of schizophrenia symptomology. This research supports assertions that artmaking has the potential to support the minimal sense of self and expand possibilities for renewed embodied and more reflective meaning-making. Explanations of findings centred around the distinct artistic style of each participant, as well as their artworks which revealed individual lifeworlds including a variety of self-positions. The inherent properties of the completed artworks also provided possibilities for renewed experiences of sociality. Additional support for the findings is drawn from recent research in the fields of early neurodevelopmental trauma, and trauma research findings within the art therapy field.
- Full Text:
- Authors: Mitchell, Julia L G
- Date: 2021
- Subjects: Schizophrenia -- Treatment , Schizophrenia -- Treatment -- South Africa -- Case studies , Art Therapy , Art Therapy -- South Africa -- Case studies , Stormberg Hospital (Eastern Cape, South Africa)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172157 , vital:42171 , 10.21504/10962/172157
- Description: Although art therapy is recommended in management programmes for individuals with a diagnosis of schizophrenia, calls have been made for more detailed explanations as to how artmaking is working. This study responds to those calls by considering the artmaking experiences of 15 mental health users with a diagnosis of schizophrenia, resident at a forensic, mental health facility in South Africa. A phenomenological approach was chosen because of its focus on lived experiences, suited to explore the embodied and pre-reflective experience of studio-based artmaking. Dialogical and narrative understandings were subsequently incorporated to account for more reflective aspects of the artmaking experience. Two main participant descriptions of artmaking, centring on feeling at home and on doing something meaningful, guided the phenomenological lifeworld method in analysing the data (interviews, artworks and field observations in art groups and exhibitions), along selected dimensions of lived experience, namely embodiment, temporality, spatiality, sociality and selfhood. These findings lend support to new phenomenological research which suggests that artmaking intersects with disrupted abilities for perceptual engagement underlying manifestations of schizophrenia symptomology. This research supports assertions that artmaking has the potential to support the minimal sense of self and expand possibilities for renewed embodied and more reflective meaning-making. Explanations of findings centred around the distinct artistic style of each participant, as well as their artworks which revealed individual lifeworlds including a variety of self-positions. The inherent properties of the completed artworks also provided possibilities for renewed experiences of sociality. Additional support for the findings is drawn from recent research in the fields of early neurodevelopmental trauma, and trauma research findings within the art therapy field.
- Full Text:
Kuntanshi yamikalile (The Future): speculative nonconformity in the works of Zambian visual artists
- Authors: Mulenga,Andrew Mukuka
- Date: 2021
- Subjects: Future in art , Africa -- In art , Art, Zambian , Art, African , Artists -- Zambia , Nyandoro, Gareth
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172203 , vital:42175 , 10.21504/10962/172203
- Description: In recent years, select African visual artists practising on the continent as well as in its diaspora have increasingly been attracted to themes that explore, portray or grapple with Africa’s future. Along with this increasing popularity of the ‘future’ or indeed ‘African futuristic’ themes by visual artists, such themes have also attracted academic consideration among various scholars, resulting primarily in topics described as ‘African Futurism’ or Afrofuturism. These are topics that may be used to disrupt what some scholars – across disciplines and in various contexts – have highlighted as the persistent presumptive notions that portray Africa as a hinterland (Hassan 1999; Sefa Dei, Hall and Goldin Rosenberg 2000; Simbao 2007; Soyinka-Airewele and Edozie 2010; Moyo 2013; Keita, L. 2014; Green 2014; Serpell 2016). This study makes an effort to critique certain aspects of ‘African Art History’ with regard to the representation of Africa, and raises the following question: How can an analysis of artistic portrayals of ‘the future’ portrayed in the works of select contemporary Zambian artists be used to critique the positioning of Africa as ‘backward’, an occurrence at the intersection of a dualistic framing of tradition versus modern. Furthermore, how can this be used to break down this dichotomy in order to challenge lingering perceptions of African belatedness? The study analyses ways in which this belatedness is challenged by the juxtaposition of traditional, contemporary and futuristic elements by discussing a series of topics and debates associated to African cultures and technology that may be deemed disconnected from the contemporary lived experiences of Africans based on the continent. The study acknowledges that there is no singular ‘African Art History’ that one can talk of and there have been various shifts in how it has been perceived. I argue that while currently the African art history that is written in the West does not simplistically position Africa as backward as it may have done in the past, there appear to be moments of a hangover of this perception (Lamp 1999:4). What started out as a largely Western scholarly discourse of African art history occurred in about the 1950s and the journal African Arts started in the 1960s. Even before contemporary African art became a big thing in the 1990s for the largely US- and Europe-based discourses there were many discussions in the US about how the ‘old’ art history tended to freeze time and that this was not appropriate (Drewal 1991 et al). In order to advance the discourse on contemporary African visual arts I present critical analyses of the select works of Zambian artists to develop interpretations of the broader uses of the aforementioned themes. The evidence that supports the core argument of this research is embedded in the images discussed throughout this dissertation. The artists featured in the study span several decades including artists who were active from the 1960s to the 1980s, such as Henry Tayali and Akwila Simpasa, as well as artists who have been practising since the 1980s, such as Chishimba Chansa and William Miko and those that are more current and have been producing work from the early 1990s and 2000s, such as Zenzele Chulu, Milumbe Haimbe, Stary Mwaba, Isaac Kalambata and Roy Jethro Phiri.
- Full Text:
- Authors: Mulenga,Andrew Mukuka
- Date: 2021
- Subjects: Future in art , Africa -- In art , Art, Zambian , Art, African , Artists -- Zambia , Nyandoro, Gareth
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172203 , vital:42175 , 10.21504/10962/172203
- Description: In recent years, select African visual artists practising on the continent as well as in its diaspora have increasingly been attracted to themes that explore, portray or grapple with Africa’s future. Along with this increasing popularity of the ‘future’ or indeed ‘African futuristic’ themes by visual artists, such themes have also attracted academic consideration among various scholars, resulting primarily in topics described as ‘African Futurism’ or Afrofuturism. These are topics that may be used to disrupt what some scholars – across disciplines and in various contexts – have highlighted as the persistent presumptive notions that portray Africa as a hinterland (Hassan 1999; Sefa Dei, Hall and Goldin Rosenberg 2000; Simbao 2007; Soyinka-Airewele and Edozie 2010; Moyo 2013; Keita, L. 2014; Green 2014; Serpell 2016). This study makes an effort to critique certain aspects of ‘African Art History’ with regard to the representation of Africa, and raises the following question: How can an analysis of artistic portrayals of ‘the future’ portrayed in the works of select contemporary Zambian artists be used to critique the positioning of Africa as ‘backward’, an occurrence at the intersection of a dualistic framing of tradition versus modern. Furthermore, how can this be used to break down this dichotomy in order to challenge lingering perceptions of African belatedness? The study analyses ways in which this belatedness is challenged by the juxtaposition of traditional, contemporary and futuristic elements by discussing a series of topics and debates associated to African cultures and technology that may be deemed disconnected from the contemporary lived experiences of Africans based on the continent. The study acknowledges that there is no singular ‘African Art History’ that one can talk of and there have been various shifts in how it has been perceived. I argue that while currently the African art history that is written in the West does not simplistically position Africa as backward as it may have done in the past, there appear to be moments of a hangover of this perception (Lamp 1999:4). What started out as a largely Western scholarly discourse of African art history occurred in about the 1950s and the journal African Arts started in the 1960s. Even before contemporary African art became a big thing in the 1990s for the largely US- and Europe-based discourses there were many discussions in the US about how the ‘old’ art history tended to freeze time and that this was not appropriate (Drewal 1991 et al). In order to advance the discourse on contemporary African visual arts I present critical analyses of the select works of Zambian artists to develop interpretations of the broader uses of the aforementioned themes. The evidence that supports the core argument of this research is embedded in the images discussed throughout this dissertation. The artists featured in the study span several decades including artists who were active from the 1960s to the 1980s, such as Henry Tayali and Akwila Simpasa, as well as artists who have been practising since the 1980s, such as Chishimba Chansa and William Miko and those that are more current and have been producing work from the early 1990s and 2000s, such as Zenzele Chulu, Milumbe Haimbe, Stary Mwaba, Isaac Kalambata and Roy Jethro Phiri.
- Full Text:
Lipid nanocarriers : a novel approach to delivering ophthalmic clarithromycin
- Authors: Makoni, Pedzisai Anotida
- Date: 2021
- Subjects: Clarithromycin , Nanomedicine , Nanostructures , Antibiotics , Eye -- Diseases -- Treatment , Ocular pharmacology , Ophthalmic drugs , Karatitis -- Chemotherapy
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/171678 , vital:42109 , 10.21504/10962/171678
- Description: The feasibility of incorporating clarithromycin (CLA) into innovative solid lipid nanoparticles (SLN) and nanostructured lipi d carriers (NLC) using hot emulsification ultrasonication (HEUS) was investigated. This approach was investigated in an attempt to address the shortcomings associated with the use of lyophilized parenteral formulations administered via the ocular route suc h as toxic reactions, intolerance and patient discomfort due to frequent insti llation of topical solutions of CLA. In particular, sustained release approaches to delivery may enhance precorneal retention, increase ocular availability and permit dose reduction or use of a longer dosing frequency when treating ocular non - tuberculous m ycobacterial (NTM) keratitis infections. This approach may potentially improve the delivery of CLA to the eye, thereby addressing some or all of the unmet clinical needs described vide infra . Prior to initiating pre - formulation, formulation development a nd optimization studies of CLA - loaded SLN and/or NLC, Design of Experiments (DoE), specifically a Central Composite Design (CCD) was used in conjunction with Response Surface Methodology (RSM) to develop and optimize a suitable method for the quantitative determination of CLA in pharmaceutical formulations and for monitoring CLA release from SLN and/or NLC in vitro . A simple, accurate, precise, sensitive and stability - indicating reversed phase - high performance liquid chromatography (RP - HPLC) method with ele ctrochemical (EC) detection was developed, validated and optimized for the in vitro analysis of CLA loaded SLN and/or NLC formulations. Pre - formulation studies were undertaken to investigate the thermal stability of CLA and bulk lipids to facilitate the s election of lipid excipients for the manufacture of nanocarriers in addition to establishing compatibility of CLA with the excipients. It was established that CLA was thermostable up to a temperature of approximately 300 °C thereby indicating that HEUS cou ld be used for the manufacture of CLA - loaded SLN and/or NLC. Lipid screening revealed that CLA i s, in general, poorly soluble in solid and liquid lipids however a combination of stearic acid (SA) and Transcutol ® HP (THP) exhibited the best dissolution pote ntial for CLA of all lipids tested . Stearic acid appears to exist as polymorphic form B prior to exposure to heat however occurs as the form C polymorph following heating at 85 °C for one hour. The best ratio for the mixture of SA and THP for the manufactu re of CLA - NLC ii was an 80:20 ( w/w ) ratio of SA: THP as the two lipids are miscible in this ratio and exhibited the greatest dissolution potential for CLA. Furthermore, an investigation of binary mixtures of CLA/SA and SA/Transcutol ® HP, in addition to eutect ic mixtures of CLA, SA and Transcutol ® HP, revealed no obvious interaction between CLA and the lipids selected for the production of the nanocarriers. Due to the relatively high solubility of CLA in THP in comparison to SA, NLC are likely to exhibit a hig her loading capacity (LC) and encapsulation efficiency (EE) for CLA than SLN. Consequently the feasibility of incorporating CLA (10% w/w ) into NLC was investigated and evaluation of the production of SLN was not undertaken as the production of these might not result in the manufacture of a delivery technology with a high EE and LC for CLA. Tween ® 20 was used as the surfactant as it is readily available, exhibits little or no cytotoxicity and is relatively cheap. Polyethylene glycol (PEG) was used as a coati ng polymer to impart muco - adhesive properties the formulated CLA - NLC. Response surface methodology (RSM) in conjunction with DoE, specifically a Box - Behnken Design (BBD) used as a screening design was used to identify a formulation composition which would produce a product that would meet the pre - defined target critical quality attributes (CQA) for the nanoparticles viz. particle size (PS) in the nano - range, polydispersity index (PDI) < 0.5, Zeta Potential (ZP) ≥ ± 30 mV, and EE > 80%. The formulation composition identified was subsequently used for the optimization of the manufacturing parameters viz. sonication time and amplitude, using a Central Composite Design (CCD) . The LC and EE, in vitro CLA release, cytotoxicity, osmolarity, pH, degree of crystallinity and lipid modification, elemental analysis and surface morphology of the optimized batch was investigated and mon itored to ensure that CLA - loaded NLC, of the desirable quality, had been produced. On the day of manufacture the mean PS and PDI of the optimized CLA - loaded NLC formulation adjusted to physiological osmolarity (250 – 450 mOsm/kg) was 461.9 ± 40.16 nm and 0. 523 ± 0.104, respectively. The ZP for the optimized NLC generated on the day of manufacture using HPLC grade water as the dispersion medium was - 20.5 ± 4.82 mV. The pH and osmolarity of the optimized CLA - loaded NLC formulation was 7.76 ± 0.01 and 316 ± iii 2 m Osm/Kg, respectively and the EE was 88.62 ± 0.23 %. The optimized NLC exhibited a decreased crystallinity in comparison to the bulk lipid materials. DSC, WAXS and FT - IR revealed that CLA was molecularly dispersed in the nanocarriers. The optimized CLA - load ed NLC exhibited muco - adhesive properties, when tested under stationary conditions using laser doppler anemometry (LDA). The optimized formulation also exhibited sustained release of CLA over 24 hours during in vitro release testing and CLA release was bes t described using the Baker - Lonsdale model . The cumulative % CLA released over 24 hours was 56.13 ± 0.23% and mass balance analysis revealed 41.38 ± 0.02% CLA had been retained in the NLC. In vitro cytotoxicity testing revealed that the optimized CLA - NLC w ere less cytotoxic to HeLa cells when compared to CLA alone and further confirmed that the lipids and excipients used in these studies were of GRAS status . Stability studies revealed that the EE reduced over 28 days by 14.42% and 5.14% when stored at 4 °C and 22 °C , respectively. In addition, the particle size increased from the nm to μm range for samples stored at 22 °C. The findings are a good starting point but require further optimization to ensure prolongation of stability. In addition , the technology requires additional developmental studies and a powder for reconstitution for use as a single - dose considered as single dose packaging may be a solution to the compromised formulation stability observed in these studies. The CLA - NLC produced in these stu dies exhibit sound product attributes which serve as a useful foundation for the novel delivery of antibiotics to the eye. The results suggest that the optimized NLC have the potential to enhance precorneal retention and increase ocular availability of CLA , which in turn may be useful to reduce the required dose and dosing frequency when administering CLA as a reconstituted solution to treat susceptible organisms that infect ocular tissues.
- Full Text:
- Authors: Makoni, Pedzisai Anotida
- Date: 2021
- Subjects: Clarithromycin , Nanomedicine , Nanostructures , Antibiotics , Eye -- Diseases -- Treatment , Ocular pharmacology , Ophthalmic drugs , Karatitis -- Chemotherapy
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/171678 , vital:42109 , 10.21504/10962/171678
- Description: The feasibility of incorporating clarithromycin (CLA) into innovative solid lipid nanoparticles (SLN) and nanostructured lipi d carriers (NLC) using hot emulsification ultrasonication (HEUS) was investigated. This approach was investigated in an attempt to address the shortcomings associated with the use of lyophilized parenteral formulations administered via the ocular route suc h as toxic reactions, intolerance and patient discomfort due to frequent insti llation of topical solutions of CLA. In particular, sustained release approaches to delivery may enhance precorneal retention, increase ocular availability and permit dose reduction or use of a longer dosing frequency when treating ocular non - tuberculous m ycobacterial (NTM) keratitis infections. This approach may potentially improve the delivery of CLA to the eye, thereby addressing some or all of the unmet clinical needs described vide infra . Prior to initiating pre - formulation, formulation development a nd optimization studies of CLA - loaded SLN and/or NLC, Design of Experiments (DoE), specifically a Central Composite Design (CCD) was used in conjunction with Response Surface Methodology (RSM) to develop and optimize a suitable method for the quantitative determination of CLA in pharmaceutical formulations and for monitoring CLA release from SLN and/or NLC in vitro . A simple, accurate, precise, sensitive and stability - indicating reversed phase - high performance liquid chromatography (RP - HPLC) method with ele ctrochemical (EC) detection was developed, validated and optimized for the in vitro analysis of CLA loaded SLN and/or NLC formulations. Pre - formulation studies were undertaken to investigate the thermal stability of CLA and bulk lipids to facilitate the s election of lipid excipients for the manufacture of nanocarriers in addition to establishing compatibility of CLA with the excipients. It was established that CLA was thermostable up to a temperature of approximately 300 °C thereby indicating that HEUS cou ld be used for the manufacture of CLA - loaded SLN and/or NLC. Lipid screening revealed that CLA i s, in general, poorly soluble in solid and liquid lipids however a combination of stearic acid (SA) and Transcutol ® HP (THP) exhibited the best dissolution pote ntial for CLA of all lipids tested . Stearic acid appears to exist as polymorphic form B prior to exposure to heat however occurs as the form C polymorph following heating at 85 °C for one hour. The best ratio for the mixture of SA and THP for the manufactu re of CLA - NLC ii was an 80:20 ( w/w ) ratio of SA: THP as the two lipids are miscible in this ratio and exhibited the greatest dissolution potential for CLA. Furthermore, an investigation of binary mixtures of CLA/SA and SA/Transcutol ® HP, in addition to eutect ic mixtures of CLA, SA and Transcutol ® HP, revealed no obvious interaction between CLA and the lipids selected for the production of the nanocarriers. Due to the relatively high solubility of CLA in THP in comparison to SA, NLC are likely to exhibit a hig her loading capacity (LC) and encapsulation efficiency (EE) for CLA than SLN. Consequently the feasibility of incorporating CLA (10% w/w ) into NLC was investigated and evaluation of the production of SLN was not undertaken as the production of these might not result in the manufacture of a delivery technology with a high EE and LC for CLA. Tween ® 20 was used as the surfactant as it is readily available, exhibits little or no cytotoxicity and is relatively cheap. Polyethylene glycol (PEG) was used as a coati ng polymer to impart muco - adhesive properties the formulated CLA - NLC. Response surface methodology (RSM) in conjunction with DoE, specifically a Box - Behnken Design (BBD) used as a screening design was used to identify a formulation composition which would produce a product that would meet the pre - defined target critical quality attributes (CQA) for the nanoparticles viz. particle size (PS) in the nano - range, polydispersity index (PDI) < 0.5, Zeta Potential (ZP) ≥ ± 30 mV, and EE > 80%. The formulation composition identified was subsequently used for the optimization of the manufacturing parameters viz. sonication time and amplitude, using a Central Composite Design (CCD) . The LC and EE, in vitro CLA release, cytotoxicity, osmolarity, pH, degree of crystallinity and lipid modification, elemental analysis and surface morphology of the optimized batch was investigated and mon itored to ensure that CLA - loaded NLC, of the desirable quality, had been produced. On the day of manufacture the mean PS and PDI of the optimized CLA - loaded NLC formulation adjusted to physiological osmolarity (250 – 450 mOsm/kg) was 461.9 ± 40.16 nm and 0. 523 ± 0.104, respectively. The ZP for the optimized NLC generated on the day of manufacture using HPLC grade water as the dispersion medium was - 20.5 ± 4.82 mV. The pH and osmolarity of the optimized CLA - loaded NLC formulation was 7.76 ± 0.01 and 316 ± iii 2 m Osm/Kg, respectively and the EE was 88.62 ± 0.23 %. The optimized NLC exhibited a decreased crystallinity in comparison to the bulk lipid materials. DSC, WAXS and FT - IR revealed that CLA was molecularly dispersed in the nanocarriers. The optimized CLA - load ed NLC exhibited muco - adhesive properties, when tested under stationary conditions using laser doppler anemometry (LDA). The optimized formulation also exhibited sustained release of CLA over 24 hours during in vitro release testing and CLA release was bes t described using the Baker - Lonsdale model . The cumulative % CLA released over 24 hours was 56.13 ± 0.23% and mass balance analysis revealed 41.38 ± 0.02% CLA had been retained in the NLC. In vitro cytotoxicity testing revealed that the optimized CLA - NLC w ere less cytotoxic to HeLa cells when compared to CLA alone and further confirmed that the lipids and excipients used in these studies were of GRAS status . Stability studies revealed that the EE reduced over 28 days by 14.42% and 5.14% when stored at 4 °C and 22 °C , respectively. In addition, the particle size increased from the nm to μm range for samples stored at 22 °C. The findings are a good starting point but require further optimization to ensure prolongation of stability. In addition , the technology requires additional developmental studies and a powder for reconstitution for use as a single - dose considered as single dose packaging may be a solution to the compromised formulation stability observed in these studies. The CLA - NLC produced in these stu dies exhibit sound product attributes which serve as a useful foundation for the novel delivery of antibiotics to the eye. The results suggest that the optimized NLC have the potential to enhance precorneal retention and increase ocular availability of CLA , which in turn may be useful to reduce the required dose and dosing frequency when administering CLA as a reconstituted solution to treat susceptible organisms that infect ocular tissues.
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Prioritising biological control agents for release against Sporobolus pyramidalis and Sporobolus natalensis (Poaceae) in Australia
- Authors: Sutton, Guy Frederick
- Date: 2021
- Subjects: Grasses -- Diseases and pests , Bruchophagus , Wasps , Alien plants -- Biological control -- Australia , Sporobolus -- Biological control -- Africa , Sporobolus -- Biological control -- Australia , Insects as biological pest control agents -- Australia , Insects as biological pest control agents -- Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172445 , vital:42201 , 10.21504/10962/172445
- Description: Sporobolus pyramidalis Beauv. and S. natalensis (Steud.) Th. Dur. and Schinz. (giant rat’s tail grass) (Poaceae), invade rangelands and pastures in eastern Australia, costing the livestock industry approximately AUS$ 60 million per annum in grazing losses. Mechanical and chemical control options are costly and largely ineffective. Biological control is viewed as the most promising control option, however this management strategy has largely been avoided for grasses, due to their perceived lack of suitably host-specific and damaging natural enemies. In this thesis, the prospects for using biological control against S. pyramidalis and S. natalensis in Australia was assessed, in light of these potential challenges. Climate matching models were used to identify high-priority geographic regions within the plants’ native distributions to survey for potential biological control agents. High-priority regions to perform surveys were identified by modelling the climatic suitability for S. pyramidalis and S. natalensis in sub-Saharan Africa (i.e. their potential native ranges’), and climatic compatibility with regions where biological control is intended in Australia. High-priority regions for S. pyramidalis included: (1) coastal East Africa, ranging from north-eastern South Africa to Uganda, including south-eastern DRC, (2) some parts of West Africa, including inland regions of the Ivory Coast and western Nigeria, (3) northern Angola and (4) eastern Madagascar, and for S. natalensis included: (1) eastern South Africa, (2) eastern Zimbabwe, (3) Burundi, (4) central Ethiopia and (5) central Madagascar. Prospective control agents collected from these regions have the highest probability of establishing and proliferating in Australia, if released. In surveys of the insect assemblages on S. pyramidalis and S. natalensis in the climatically-matched region of eastern South Africa fifteen insect herbivores associated with the grasses were identified. Insect feeding guild, geographic distributions, and seasonal abundances suggest that three stem-boring phytophagous wasps, Tetramesa sp. 1, Tetramesa sp. 2 and Bruchophagus sp. 1 (Hymenoptera: Eurytomidae), have potential as control agents. Species accumulation curves indicated that additional surveys in South Africa are unlikely to yield additional potential control agents. Field host-range surveys of 47 non-target grass species in South Africa showed that Tetramesa sp. 1, Tetramesa sp. 2, and Bruchophagus sp. 1, were only recorded from S. pyramidalis and S. natalensis. Integrating field host-range with phylogenetic relationships between plant species indicated that no native Australian Sporobolus species or economic crops and pastures are expected to be attacked by these wasps. All three wasp species are predicted to be suitably host-specific for release in Australia. Three other endophagous herbivores attacked non-target native African Sporobolus species that share a close phylogenetic relationship to native Australian Sporobolus species, and therefore, demonstrate considerable risk of non-target damage. These species should not be considered as potential control agents. Under native-range, open-field conditions, Tetramesa sp. 1 caused an approximately 5-fold greater reduction in plant survival and reproductive output than Tetramesa sp. 2 and Bruchophagus sp. 1. Tetramesa sp. 1 in combination with Tetramesa sp. 2 did not significantly increase the level of damage, while Bruchophagus sp. 1 may decrease the efficiency of Tetramesa sp. 1, if released in combination. Tetramesa 1 is therefore the most promising candidate agent. Prioritising potential agents using predicted efficacy allowed otherwise equally suitable prospective agents to be prioritised in a strategic manner. Prioritising which natural enemies to target as biological control agents is a complex task. Field host range and damage assessments in the native range may provide more realistic data than typical studies performed under artificial conditions in a laboratory or quarantine. Moreover, it could assist practitioners in prioritising the most suitable agent(s) at the earliest stage in the programme as possible. This study demonstrated that grasses are suitable targets for biological control as they can harbour host-specific and damaging natural enemies.
- Full Text:
- Authors: Sutton, Guy Frederick
- Date: 2021
- Subjects: Grasses -- Diseases and pests , Bruchophagus , Wasps , Alien plants -- Biological control -- Australia , Sporobolus -- Biological control -- Africa , Sporobolus -- Biological control -- Australia , Insects as biological pest control agents -- Australia , Insects as biological pest control agents -- Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172445 , vital:42201 , 10.21504/10962/172445
- Description: Sporobolus pyramidalis Beauv. and S. natalensis (Steud.) Th. Dur. and Schinz. (giant rat’s tail grass) (Poaceae), invade rangelands and pastures in eastern Australia, costing the livestock industry approximately AUS$ 60 million per annum in grazing losses. Mechanical and chemical control options are costly and largely ineffective. Biological control is viewed as the most promising control option, however this management strategy has largely been avoided for grasses, due to their perceived lack of suitably host-specific and damaging natural enemies. In this thesis, the prospects for using biological control against S. pyramidalis and S. natalensis in Australia was assessed, in light of these potential challenges. Climate matching models were used to identify high-priority geographic regions within the plants’ native distributions to survey for potential biological control agents. High-priority regions to perform surveys were identified by modelling the climatic suitability for S. pyramidalis and S. natalensis in sub-Saharan Africa (i.e. their potential native ranges’), and climatic compatibility with regions where biological control is intended in Australia. High-priority regions for S. pyramidalis included: (1) coastal East Africa, ranging from north-eastern South Africa to Uganda, including south-eastern DRC, (2) some parts of West Africa, including inland regions of the Ivory Coast and western Nigeria, (3) northern Angola and (4) eastern Madagascar, and for S. natalensis included: (1) eastern South Africa, (2) eastern Zimbabwe, (3) Burundi, (4) central Ethiopia and (5) central Madagascar. Prospective control agents collected from these regions have the highest probability of establishing and proliferating in Australia, if released. In surveys of the insect assemblages on S. pyramidalis and S. natalensis in the climatically-matched region of eastern South Africa fifteen insect herbivores associated with the grasses were identified. Insect feeding guild, geographic distributions, and seasonal abundances suggest that three stem-boring phytophagous wasps, Tetramesa sp. 1, Tetramesa sp. 2 and Bruchophagus sp. 1 (Hymenoptera: Eurytomidae), have potential as control agents. Species accumulation curves indicated that additional surveys in South Africa are unlikely to yield additional potential control agents. Field host-range surveys of 47 non-target grass species in South Africa showed that Tetramesa sp. 1, Tetramesa sp. 2, and Bruchophagus sp. 1, were only recorded from S. pyramidalis and S. natalensis. Integrating field host-range with phylogenetic relationships between plant species indicated that no native Australian Sporobolus species or economic crops and pastures are expected to be attacked by these wasps. All three wasp species are predicted to be suitably host-specific for release in Australia. Three other endophagous herbivores attacked non-target native African Sporobolus species that share a close phylogenetic relationship to native Australian Sporobolus species, and therefore, demonstrate considerable risk of non-target damage. These species should not be considered as potential control agents. Under native-range, open-field conditions, Tetramesa sp. 1 caused an approximately 5-fold greater reduction in plant survival and reproductive output than Tetramesa sp. 2 and Bruchophagus sp. 1. Tetramesa sp. 1 in combination with Tetramesa sp. 2 did not significantly increase the level of damage, while Bruchophagus sp. 1 may decrease the efficiency of Tetramesa sp. 1, if released in combination. Tetramesa 1 is therefore the most promising candidate agent. Prioritising potential agents using predicted efficacy allowed otherwise equally suitable prospective agents to be prioritised in a strategic manner. Prioritising which natural enemies to target as biological control agents is a complex task. Field host range and damage assessments in the native range may provide more realistic data than typical studies performed under artificial conditions in a laboratory or quarantine. Moreover, it could assist practitioners in prioritising the most suitable agent(s) at the earliest stage in the programme as possible. This study demonstrated that grasses are suitable targets for biological control as they can harbour host-specific and damaging natural enemies.
- Full Text:
The application of human factors and ergonomics (HFE) to community-sport organisations in resource scarce contexts: a case study of grassroots football in Makana, Eastern Cape
- Authors: Bennett, Ryan
- Date: 2021
- Subjects: Makana Local Football Association (South Africa) , Human engineering , Soccer teams -- South Africa -- Makhanda -- Management , Soccer -- Management -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172412 , vital:42198 , 10.21504/10962/172412
- Description: Background: Modern Human Factors and Ergonomics (HFE) focuses on the optimisation of complex socio-technical systems and has been challenged to contribute to broader societal issues. An example is within grassroots football organisations in resource-scarce areas such as Makana, South Africa. Through embedded participatory approaches, the research problem was co-constructed: To investigate the socio-technical system of the Makana Local Football Association (LFA). Method: A useful complex system modelling tool is that of Cognitive Work Analysis (CWA), with its 5 phases used to identify constraints and affordances. Three perspectives were adopted for the application of an adapted (to suit participant characteristics) CWA to the Makana LFA: 1) how work is prescribed by the governing body SAFA, 2) how subject matter experts (SME) disclose its current functioning, and 3) how SMEs imagine it could function. Five SMEs attended 12 three-hour workshops to complete the latter two perspectives. Results: The composite work domain analysis between work as prescribed and work as disclosed identified significant mismatches between how policymakers envision the system and how SMEs report its functioning. Key differences in perspectives included the fundamental purpose of the Makana LFA, while only four of 22 functions operate within the Makana LFA. Participants also identified key affordances for the LFA such as reorientation as a community sports organisation. Discussion: Comparison between perspectives indicated four mismatches. 1) SAFA views the LFA as the foundation of the talent identification and development infrastructure of South African football. SMEs view it as a community centred organisation. 2) A lack of human capacity is evident at the community level of Makana football. 3) Funding and assets are absent at this grassroots level. 4) The LFA relies on other stakeholders, but these relationships are not formalised. Policymakers, therefore, have a lack of knowledge of the contextual challenges faced by LFA administrators. It is recommended that SAFA view the LFA as a community sport organisation, focusing on improving human capacity, increasing funding, and formalising stakeholder networks. Furthermore, conceptual models from CWA provide explicit socio-technical system redesign recommendations. Conclusion: Large mismatches between the organising body SAFA and the actual functioning of the LFA significantly hinder the effective management and running of football at a grassroots level in resource-scarce contexts in South Africa. The perspectives approach to CWA was useful in elucidating the constraints and affordances of the Makana LFA socio-technical system and informing redesign opportunities. Systems HFE methodology is therefore well placed to contribute to broader societal issues within resources scarce contexts such as football in Makana. Furthermore, the philosophical underpinnings of systems based HFE were successful in the development of sustainable participatory research within the South African grassroots football context.
- Full Text:
- Authors: Bennett, Ryan
- Date: 2021
- Subjects: Makana Local Football Association (South Africa) , Human engineering , Soccer teams -- South Africa -- Makhanda -- Management , Soccer -- Management -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172412 , vital:42198 , 10.21504/10962/172412
- Description: Background: Modern Human Factors and Ergonomics (HFE) focuses on the optimisation of complex socio-technical systems and has been challenged to contribute to broader societal issues. An example is within grassroots football organisations in resource-scarce areas such as Makana, South Africa. Through embedded participatory approaches, the research problem was co-constructed: To investigate the socio-technical system of the Makana Local Football Association (LFA). Method: A useful complex system modelling tool is that of Cognitive Work Analysis (CWA), with its 5 phases used to identify constraints and affordances. Three perspectives were adopted for the application of an adapted (to suit participant characteristics) CWA to the Makana LFA: 1) how work is prescribed by the governing body SAFA, 2) how subject matter experts (SME) disclose its current functioning, and 3) how SMEs imagine it could function. Five SMEs attended 12 three-hour workshops to complete the latter two perspectives. Results: The composite work domain analysis between work as prescribed and work as disclosed identified significant mismatches between how policymakers envision the system and how SMEs report its functioning. Key differences in perspectives included the fundamental purpose of the Makana LFA, while only four of 22 functions operate within the Makana LFA. Participants also identified key affordances for the LFA such as reorientation as a community sports organisation. Discussion: Comparison between perspectives indicated four mismatches. 1) SAFA views the LFA as the foundation of the talent identification and development infrastructure of South African football. SMEs view it as a community centred organisation. 2) A lack of human capacity is evident at the community level of Makana football. 3) Funding and assets are absent at this grassroots level. 4) The LFA relies on other stakeholders, but these relationships are not formalised. Policymakers, therefore, have a lack of knowledge of the contextual challenges faced by LFA administrators. It is recommended that SAFA view the LFA as a community sport organisation, focusing on improving human capacity, increasing funding, and formalising stakeholder networks. Furthermore, conceptual models from CWA provide explicit socio-technical system redesign recommendations. Conclusion: Large mismatches between the organising body SAFA and the actual functioning of the LFA significantly hinder the effective management and running of football at a grassroots level in resource-scarce contexts in South Africa. The perspectives approach to CWA was useful in elucidating the constraints and affordances of the Makana LFA socio-technical system and informing redesign opportunities. Systems HFE methodology is therefore well placed to contribute to broader societal issues within resources scarce contexts such as football in Makana. Furthermore, the philosophical underpinnings of systems based HFE were successful in the development of sustainable participatory research within the South African grassroots football context.
- Full Text:
The electrocatalytic response of metallophthalocyanines when clicked to electrodes and to nanomaterials
- Authors: Mpeta, Lekhetho Simon
- Date: 2021
- Subjects: Phthalocyanines , Nanostructured materials , Electrocatalysis , Nanoparticles , Environmental chemistry , Electrodes , Organic wastes -- Purification
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172191 , vital:42174 , 10.21504/10962/172191
- Description: Conjugates of nanomaterials and metallophthalocyanines (MPcs) have been prepared and their electrocatalytic activity studied. The prepared nanomaterials are zinc oxide and silver nanoparticles, reduced graphene oxide nanosheets and semiconductor quantum dots. The MPcs used in this work are cobalt (II) (1a), manganese(III) (1b) and iron (II) (1c) 2,9(10),16(17),23(24)- tetrakis 4-((4-ethynylbenzyl) oxy) phthalocyaninato, 2,9(10),16(17),23(24)- tetrakis(5-pentyn-oxy) cobalt (II) phthalocyaninato (2), 9(10),16(17),23(24)- tris-[4-tert-butylphenoxy)-2- (4-ethylbezyl-oxy) cobalt (II) phthalocyaninato (3), 9(10),16(17),23(24)- tris-[4-tertbutylphenoxy)-2-(pent-4yn-yloxy)] cobalt (II) phthalocyaninato (4), cobalt (II) (5a) and manganese (III) (5b) 2,9(10),16(17),23(24)- tetrakis [4-(4-(5-chloro-1H-benzo [d]imidazol-2-yl)phenoxy] phthalocyaninato and 9(10),16(17),23(24)- tris tert butyl phenoxy- 2- [4-(4-(5-chloro-1H-benzo[d]imidazole-2-yl)phenoxy] cobalt (II) phthalocyaninato (6). Some of these MPcs (1a, 3 and 4) were directly clicked on azide grafted electrode, while some (1b, 1c, 2, 5a and 5b) were clicked to azide functionalised nanomaterials and then drop-dried on the electrodes. One phthalocyanine (5b) was drop-dried on the electrode then silver nanoparticles were electrodeposited on it taking advantage of metal-N bond. Scanning electrochemical microscopy, voltammetry, chronoamperometry, electrochemical impedance spectroscopy are among electrochemical methods used to characterise modified electrodes. Transmission electron microscopy, X-ray photoelectron spectroscopy, Xray diffractometry, Raman spectroscopy and infrared spectroscopy were employed to study surface functionalities, morphology and topography of the nanomaterials and complexes. Electrocatalytic activity of the developed materials were studied towards oxidation of 2-mercaptoethanol, hydrazine and hydrogen peroxide while the reduction study was based on oxygen and hydrogen peroxide. In general, the conjugates displayed superior catalytic activity when compared to individual materials. Complex 2 alone and when conjugated to zinc oxide nanoparticles were studied for their nonlinear optical behaviour. And the same materials were explored for their hydrazine detection capability. The aim of this study was to develop sensitive, selective and affordable sensors for selected organic waste pollutants. Conjugates were found to achieve the aim of the study compared to when individual materials were employed.
- Full Text:
- Authors: Mpeta, Lekhetho Simon
- Date: 2021
- Subjects: Phthalocyanines , Nanostructured materials , Electrocatalysis , Nanoparticles , Environmental chemistry , Electrodes , Organic wastes -- Purification
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/172191 , vital:42174 , 10.21504/10962/172191
- Description: Conjugates of nanomaterials and metallophthalocyanines (MPcs) have been prepared and their electrocatalytic activity studied. The prepared nanomaterials are zinc oxide and silver nanoparticles, reduced graphene oxide nanosheets and semiconductor quantum dots. The MPcs used in this work are cobalt (II) (1a), manganese(III) (1b) and iron (II) (1c) 2,9(10),16(17),23(24)- tetrakis 4-((4-ethynylbenzyl) oxy) phthalocyaninato, 2,9(10),16(17),23(24)- tetrakis(5-pentyn-oxy) cobalt (II) phthalocyaninato (2), 9(10),16(17),23(24)- tris-[4-tert-butylphenoxy)-2- (4-ethylbezyl-oxy) cobalt (II) phthalocyaninato (3), 9(10),16(17),23(24)- tris-[4-tertbutylphenoxy)-2-(pent-4yn-yloxy)] cobalt (II) phthalocyaninato (4), cobalt (II) (5a) and manganese (III) (5b) 2,9(10),16(17),23(24)- tetrakis [4-(4-(5-chloro-1H-benzo [d]imidazol-2-yl)phenoxy] phthalocyaninato and 9(10),16(17),23(24)- tris tert butyl phenoxy- 2- [4-(4-(5-chloro-1H-benzo[d]imidazole-2-yl)phenoxy] cobalt (II) phthalocyaninato (6). Some of these MPcs (1a, 3 and 4) were directly clicked on azide grafted electrode, while some (1b, 1c, 2, 5a and 5b) were clicked to azide functionalised nanomaterials and then drop-dried on the electrodes. One phthalocyanine (5b) was drop-dried on the electrode then silver nanoparticles were electrodeposited on it taking advantage of metal-N bond. Scanning electrochemical microscopy, voltammetry, chronoamperometry, electrochemical impedance spectroscopy are among electrochemical methods used to characterise modified electrodes. Transmission electron microscopy, X-ray photoelectron spectroscopy, Xray diffractometry, Raman spectroscopy and infrared spectroscopy were employed to study surface functionalities, morphology and topography of the nanomaterials and complexes. Electrocatalytic activity of the developed materials were studied towards oxidation of 2-mercaptoethanol, hydrazine and hydrogen peroxide while the reduction study was based on oxygen and hydrogen peroxide. In general, the conjugates displayed superior catalytic activity when compared to individual materials. Complex 2 alone and when conjugated to zinc oxide nanoparticles were studied for their nonlinear optical behaviour. And the same materials were explored for their hydrazine detection capability. The aim of this study was to develop sensitive, selective and affordable sensors for selected organic waste pollutants. Conjugates were found to achieve the aim of the study compared to when individual materials were employed.
- Full Text: