An investigation into the performance of smallholder irrigation schemes in Limpopo Province, South Africa: success factors, typologies and implications for development
- Denison, Jonathan Anthony Noel
- Authors: Denison, Jonathan Anthony Noel
- Date: 2019
- Subjects: Irrigation projects -- South Africa -- Limpopo , Farms, Small -- South Africa -- Limpopo , Land use -- South Africa -- Limpopo , Water-supply -- South Africa -- Limpopo
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92317 , vital:30709
- Description: The research aimed to determine the factors that contribute to the success or failure of smallholder irrigation schemes in the Limpopo Province. It focussed on public-schemes where farmers share the water system Limpopo Province has more than half of the smallholder irrigation schemes in the country with an equipped area of approximately 28 000 ha. The main aims of the research were to identify key factors that explain performance and to develop a contemporary irrigation scheme typology. The research intended to provide a better perspective on how to focus investments across the multiple thematic areas that are associated with sustained and profitable irrigation farming activity. A survey of 102 irrigation schemes was conducted, comprising 82% of the population of schemes greater than 20 ha in Limpopo Province. The quantitative survey complemented prior in-depth qualitative research undertaken on Limpopo schemes. Data was consolidated into five performance indicators and 13 characteristic factors that impact performance. Schemes were viewed as technical and socio-biological systems where performance was determined by the dynamic interaction of multiple factors. The analysis was done in a complex systems framework using correlation, cluster and principle component analysis. It was postulated that over-arching concepts of productivity, profitability and manageability would explain why schemes succeed or fail. The schemes were found to be relatively very small in size with three quarters (74.8%) of them falling in the 50 to 250 ha size range, and only 11 schemes larger than 250 ha. Average plot sizes were 1.34 ha with a wide range between 0.18 and 16.25 ha. There were 65 operational schemes (equivalent to 63.7%), and 37 had failed (equivalent to 36.3%). Using a criterion for success of greater than 50% cropping intensity (to align with other studies and below which schemes can be considered to have failed), the success rate of the Limpopo schemes was 58%. The result was similar to the rest of South Africa and the same as the average rate for SADC identified in other studies using the same criterion. The schemes exhibited a mixed production purpose on average, with a significant market emphasis indicating these schemes have largely evolved from ‘food schemes’ to partly market-farming. Main crops grown were summer-maize and winter fresh-vegetables and cropping intensities on operational schemes ranged widely from 10% to 175%, with an average of 94%. Failure was associated with three dominant factors: energy type; infrastructure condition; and water resource constraints. The first two factors showed that manageability of technology was important. There is strong empirical evidence that pumped smallholder schemes are vulnerable in their physical form, prone to functional and financial failure, live much shorter lives, and perform no better than gravity-canal schemes. Out of the 37 schemes that failed, 34 (91.8%) were pumped. Pumped schemes tend to collapse suddenly while young and exhibit lower cut-off thresholds in productivity that, when crossed, trigger collapse. They also have much lower resilience to factors such as water stress or low farm-profitability. Pumped schemes need higher levels farm sophistication, market-oriented farming, and operational capability to keep the pumping pressure up. Water resource constraints were widespread, considerably more so on gravity schemes. Commercialising farmers were inhibited by lack of access to knowledge. Success was associated with numerous factors, but two findings stand out; the performance of gravity systems and the prevalence of land-exchange activity; the latter enabled by institutional flexibility and reflecting a process of ‘bricolage’ at play. Increased plot size was associated with increased commercialisation and, when larger than 1.8 ha, only commercialised farming was pursued. Market proximity seemed to play a role in increased longevity and to market access in commercialisation. These findings highlighted the importance of productivity and profitability in explaining success. Gravity schemes performed much more strongly in terms of longevity (nearly four times longer-lived) and similarly to pumped schemes in terms of cropping intensity. This was achieved under much greater water stress and with considerably worse infrastructure condition. Water efficiency was determined to be high on half of the schemes that were using short-furrow irrigation; equivalent, in a basin perspective, to drip irrigation. Two of the three top performing schemes (>150% intensity) were old gravity schemes. Farmers on approximately 75% of Limpopo smallholder schemes are currently engaging in land exchange transactions in a highly insecure and un-formalised institutional setup. Land exchange prevalence longer than two years was moderately associated with cropping intensity and strongly associated with commercialisation. This result has three important implications. First, it suggests that more land is utilised on the schemes when there is vibrant land-leasing activity. Secondly, schemes with a higher prevalence of long-term leasing seem to have a strong tendency to be more commercialised. Thirdly, the duration of the lease is significant, as neither single-season, nor annual leases yielded any positive associations, while those exchanges that were two years or longer, were associated with increased performance. These findings highlight the potential for longer-term land-exchange interventions to address the widespread low land utilisation on smallholder schemes, and to catalyse more commercially-oriented farming. An irrigation scheme typology was derived from the cluster analysis and was aligned to a contemporary irrigation farming typology. The key descriptors included technology type, purpose of farming and scheme management type. By matching scheme type to the farmer typology (or typologies), strategic decisions regarding technology choices for infrastructure, land, and water institutional interventions can be better informed. All schemes demand attention to the multiple factors required to achieve performance, not least water-tenure security, irrigation management organisational development, and infrastructure modernisation. Complexity was demonstrated by the finding that multiple factors contribute to success, and that there are many dimensions that change independently and have a cascading effect through the system in ways that are difficult to predict. Agricultural systems support to achieve productivity and profitability are essential for success. The research findings lead to the recommendation that, in addition, strategic planners must also consider the implications of the dominant factors of water-technology choices so that these are manageable, and the dynamics of farm-size change based on land exchange processes, in order to harness new opportunities to maximise irrigation scheme performance in future.
- Full Text:
- Date Issued: 2019
- Authors: Denison, Jonathan Anthony Noel
- Date: 2019
- Subjects: Irrigation projects -- South Africa -- Limpopo , Farms, Small -- South Africa -- Limpopo , Land use -- South Africa -- Limpopo , Water-supply -- South Africa -- Limpopo
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92317 , vital:30709
- Description: The research aimed to determine the factors that contribute to the success or failure of smallholder irrigation schemes in the Limpopo Province. It focussed on public-schemes where farmers share the water system Limpopo Province has more than half of the smallholder irrigation schemes in the country with an equipped area of approximately 28 000 ha. The main aims of the research were to identify key factors that explain performance and to develop a contemporary irrigation scheme typology. The research intended to provide a better perspective on how to focus investments across the multiple thematic areas that are associated with sustained and profitable irrigation farming activity. A survey of 102 irrigation schemes was conducted, comprising 82% of the population of schemes greater than 20 ha in Limpopo Province. The quantitative survey complemented prior in-depth qualitative research undertaken on Limpopo schemes. Data was consolidated into five performance indicators and 13 characteristic factors that impact performance. Schemes were viewed as technical and socio-biological systems where performance was determined by the dynamic interaction of multiple factors. The analysis was done in a complex systems framework using correlation, cluster and principle component analysis. It was postulated that over-arching concepts of productivity, profitability and manageability would explain why schemes succeed or fail. The schemes were found to be relatively very small in size with three quarters (74.8%) of them falling in the 50 to 250 ha size range, and only 11 schemes larger than 250 ha. Average plot sizes were 1.34 ha with a wide range between 0.18 and 16.25 ha. There were 65 operational schemes (equivalent to 63.7%), and 37 had failed (equivalent to 36.3%). Using a criterion for success of greater than 50% cropping intensity (to align with other studies and below which schemes can be considered to have failed), the success rate of the Limpopo schemes was 58%. The result was similar to the rest of South Africa and the same as the average rate for SADC identified in other studies using the same criterion. The schemes exhibited a mixed production purpose on average, with a significant market emphasis indicating these schemes have largely evolved from ‘food schemes’ to partly market-farming. Main crops grown were summer-maize and winter fresh-vegetables and cropping intensities on operational schemes ranged widely from 10% to 175%, with an average of 94%. Failure was associated with three dominant factors: energy type; infrastructure condition; and water resource constraints. The first two factors showed that manageability of technology was important. There is strong empirical evidence that pumped smallholder schemes are vulnerable in their physical form, prone to functional and financial failure, live much shorter lives, and perform no better than gravity-canal schemes. Out of the 37 schemes that failed, 34 (91.8%) were pumped. Pumped schemes tend to collapse suddenly while young and exhibit lower cut-off thresholds in productivity that, when crossed, trigger collapse. They also have much lower resilience to factors such as water stress or low farm-profitability. Pumped schemes need higher levels farm sophistication, market-oriented farming, and operational capability to keep the pumping pressure up. Water resource constraints were widespread, considerably more so on gravity schemes. Commercialising farmers were inhibited by lack of access to knowledge. Success was associated with numerous factors, but two findings stand out; the performance of gravity systems and the prevalence of land-exchange activity; the latter enabled by institutional flexibility and reflecting a process of ‘bricolage’ at play. Increased plot size was associated with increased commercialisation and, when larger than 1.8 ha, only commercialised farming was pursued. Market proximity seemed to play a role in increased longevity and to market access in commercialisation. These findings highlighted the importance of productivity and profitability in explaining success. Gravity schemes performed much more strongly in terms of longevity (nearly four times longer-lived) and similarly to pumped schemes in terms of cropping intensity. This was achieved under much greater water stress and with considerably worse infrastructure condition. Water efficiency was determined to be high on half of the schemes that were using short-furrow irrigation; equivalent, in a basin perspective, to drip irrigation. Two of the three top performing schemes (>150% intensity) were old gravity schemes. Farmers on approximately 75% of Limpopo smallholder schemes are currently engaging in land exchange transactions in a highly insecure and un-formalised institutional setup. Land exchange prevalence longer than two years was moderately associated with cropping intensity and strongly associated with commercialisation. This result has three important implications. First, it suggests that more land is utilised on the schemes when there is vibrant land-leasing activity. Secondly, schemes with a higher prevalence of long-term leasing seem to have a strong tendency to be more commercialised. Thirdly, the duration of the lease is significant, as neither single-season, nor annual leases yielded any positive associations, while those exchanges that were two years or longer, were associated with increased performance. These findings highlight the potential for longer-term land-exchange interventions to address the widespread low land utilisation on smallholder schemes, and to catalyse more commercially-oriented farming. An irrigation scheme typology was derived from the cluster analysis and was aligned to a contemporary irrigation farming typology. The key descriptors included technology type, purpose of farming and scheme management type. By matching scheme type to the farmer typology (or typologies), strategic decisions regarding technology choices for infrastructure, land, and water institutional interventions can be better informed. All schemes demand attention to the multiple factors required to achieve performance, not least water-tenure security, irrigation management organisational development, and infrastructure modernisation. Complexity was demonstrated by the finding that multiple factors contribute to success, and that there are many dimensions that change independently and have a cascading effect through the system in ways that are difficult to predict. Agricultural systems support to achieve productivity and profitability are essential for success. The research findings lead to the recommendation that, in addition, strategic planners must also consider the implications of the dominant factors of water-technology choices so that these are manageable, and the dynamics of farm-size change based on land exchange processes, in order to harness new opportunities to maximise irrigation scheme performance in future.
- Full Text:
- Date Issued: 2019
Analyses of Retail and Transport Geography of Liquefied Petroleum Products in Ibadan metropolis, Nigeria
- Authors: Ajayi, Adeyinka Peter
- Date: 2019
- Subjects: Petroleum products
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/19065 , vital:40090
- Description: This study analyzed the effects that spatial arrangement of petroleum products retail outlets and the supply chain management techniques employed for products distribution (for both intra city and intercity shipments) have on the retailing dynamism of petroleum products within built environment and peripherals of Ibadan metropolis over the years. Specifically, the study investigated the differentials in the spatial configurations of petroleum products retail outlets between the core and periurban zones of the metropolis. An attempt was made to determine the explanatory variables that influence the spatial distributional decisions of petroleum products retail outlets in the metropolis. The study equally examined how the supply chain management (SCM) techniques by the different categories of the retail outlet owners influence the efficient and cost effective distribution of petroleum products. Lastly an attempt was made to analyze the relationship between the socio-economic attributes of the haulers and the achievement of compliance to the HSE stipulations guiding the conveyance of petroleum products. The theoretical underpinnings for the research were a derivative of the amalgamation of normative and psychological theories from geography, psychology, SCM and retailing science. Specifically, Expectation Disconfirmation Theory (EDT), Distributive Justice, Central Place Theory (CPT) Theories of Urban Impact (TUI) and Theory of Constraint (ToC) were the theories utilized in the study. For the achievement of the first objective which was to investigate the possible differential in the compliance rate between spatial pattern of fuel retail outlets in the core and peripheral zones of Ibadan metropolis, the first hypothesis of the study (which examined if there was no significant difference in the rate of compliance to the planning authority stipulations guiding the location pattern of petroleum product retail outlets between those located in the built up and xxiv peripheral zones of the city), was tested through the use of buffering and proximity analyses in the ArcMap environment of ArcGIS 10.1, while inferential statistical tool of an independent-samples t-test was conducted to compare the rate of compliance to the stipulations guiding the locations of these outlets in both the core and the peripheral zones. The result from the GIS analysis indicated that 33 (15.56%) out of the 220 outlets in the core zone of the metropolis complied with the planning stipulations guiding the location of fuel retail outlets. For the peripheral zone, out of the 220 fuel retail outlets 24 (10.90%) complied with the stipulations. The result from the t- test which was employed to test the hypothesis indicated that no significant difference existed in the rate of compliance t (263) =-2.66, p = 0.08 between fuel retail outlets in the core zone (M=3.9, SD=1.4) and peripheral zone (M=4.5, SD=1.79). The alternate hypothesis which stated that ―no significant difference existed in the compliance rate between fuel retail outlets located in the two zones‖ is accepted. For the achievement of the second objective of the study which was to analyze the factors which determine the location of fuel retail outlets both in the core and peripheral zones of Ibadan metropolis. All the managers/owners of the 432 fuel retail outlets in the metropolis were sampled out of which 256 questionnaires were retrieved for the purpose of this analysis. The breakdown of the socio-economic characteristics of the sampled respondents showed that the gender distribution showed that 194 (75.78%) of the respondents were males, while 64 (24.22 %) were females. The average age of the sampled population was 33.70 years. The mixed method was employed for the achievement of the second objective of this study. Logistic Regression Model (LRM) was employed to test the hypothesis and the result revealed that the inclusion of the independent variables in the model increased the overall level of it accuracy. The overall significance revealed that the Model Chi- xxv Square, derived from the likelihood fitted is also accurate (X2 = 43.47, df=5, p>.05). The model chi-square value of 43.47 (approximately 44% ) was significant. Thus, the indication is that the model has a good fit in predicting the possibility of a fuel retail outlet being located in the core or peripheral zone of the metropolis as determined by the explanatory variables (the independent variables accounted for about 44% of possible factors which determined whether a fuel retail outlets is located either within the core or peripheral zones of the metropolis. The remaining 56% are factors not considered in the study). The result gotten from the in depth interview sessions corroborated the findings from the tested hypothesis. The third objective was to examine the effects which the supply chain technique employed (either vertically integrated model or third-party arrangement) has on the achievement of efficient and effective distribution of the products. In order to achieve this objective, all the 389 registered members of Petroleum Tanker Drivers (PTD) association who are members of the PTD in the metropolis were sampled, 265 (around 70%) of the distributed questionnaires were retrieved and used for the analysis. In depth interview sessions were also conducted with three different managers of the three major conglomerates in the downstream sector of the Nigerian petroleum sector. The result of one-way between subjects (ANOVA) which was conducted to compare differences in the management and performances of haulage services outsourced to the 3PLS and those run under VIM showed that there was a significant effect of ownership type on management performance (F (2,262) = 60.26, p<.05). The null hypothesis was therefore rejected while the alternate hypothesis was accepted. The findings from the interview sessions posted similar results. The fourth and final objective was to analyze the effect that the socio-economic attributes of the participants (haulers and managers of retail outlets) involved in the distribution of xxvi petroleum products has on the safe, efficient and cost-effective distribution of product and this was done through the use of descriptive statistics, inferential statistics and incisive analysis of the interview sessions. A total number of 265 (70%) out of the 389 registered members of Petroleum Tanker Driver Association (PTDA) participated in the study. Multiple regression analysis (MRA) was used to test this hypothesis. The result from the statistical analysis show that the use of stimulant, work condition, marital status and educational attainment/literacy level have joint influence on compliance (R2 = 0.31, F (4,260) = 29.72, p<.05). On the basis of the foregoing, the hypothesis is thus accepted. The result from the interview sessions confirmed the existence of strong relationship between the explanatory variables and the hypothetical dependant variable. The study recommended a review of the planning processes guiding the establishment of fuel retail outlets. The study also advocated that retailers should endeavour to have stronger control over the supply chain of their products this could done by investing more in VIM rather than outsourcing such functions to 3PLs. This will help in better business performances. Government agencies in charge of monitoring drug abuse among haulers are advised to be more proactive by the duo of prevention and punishment strategies. This should include advocacy campaign against drug abuse. Different ranges of punishments should also be meted out for individual haulers found culpable.
- Full Text:
- Date Issued: 2019
- Authors: Ajayi, Adeyinka Peter
- Date: 2019
- Subjects: Petroleum products
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/19065 , vital:40090
- Description: This study analyzed the effects that spatial arrangement of petroleum products retail outlets and the supply chain management techniques employed for products distribution (for both intra city and intercity shipments) have on the retailing dynamism of petroleum products within built environment and peripherals of Ibadan metropolis over the years. Specifically, the study investigated the differentials in the spatial configurations of petroleum products retail outlets between the core and periurban zones of the metropolis. An attempt was made to determine the explanatory variables that influence the spatial distributional decisions of petroleum products retail outlets in the metropolis. The study equally examined how the supply chain management (SCM) techniques by the different categories of the retail outlet owners influence the efficient and cost effective distribution of petroleum products. Lastly an attempt was made to analyze the relationship between the socio-economic attributes of the haulers and the achievement of compliance to the HSE stipulations guiding the conveyance of petroleum products. The theoretical underpinnings for the research were a derivative of the amalgamation of normative and psychological theories from geography, psychology, SCM and retailing science. Specifically, Expectation Disconfirmation Theory (EDT), Distributive Justice, Central Place Theory (CPT) Theories of Urban Impact (TUI) and Theory of Constraint (ToC) were the theories utilized in the study. For the achievement of the first objective which was to investigate the possible differential in the compliance rate between spatial pattern of fuel retail outlets in the core and peripheral zones of Ibadan metropolis, the first hypothesis of the study (which examined if there was no significant difference in the rate of compliance to the planning authority stipulations guiding the location pattern of petroleum product retail outlets between those located in the built up and xxiv peripheral zones of the city), was tested through the use of buffering and proximity analyses in the ArcMap environment of ArcGIS 10.1, while inferential statistical tool of an independent-samples t-test was conducted to compare the rate of compliance to the stipulations guiding the locations of these outlets in both the core and the peripheral zones. The result from the GIS analysis indicated that 33 (15.56%) out of the 220 outlets in the core zone of the metropolis complied with the planning stipulations guiding the location of fuel retail outlets. For the peripheral zone, out of the 220 fuel retail outlets 24 (10.90%) complied with the stipulations. The result from the t- test which was employed to test the hypothesis indicated that no significant difference existed in the rate of compliance t (263) =-2.66, p = 0.08 between fuel retail outlets in the core zone (M=3.9, SD=1.4) and peripheral zone (M=4.5, SD=1.79). The alternate hypothesis which stated that ―no significant difference existed in the compliance rate between fuel retail outlets located in the two zones‖ is accepted. For the achievement of the second objective of the study which was to analyze the factors which determine the location of fuel retail outlets both in the core and peripheral zones of Ibadan metropolis. All the managers/owners of the 432 fuel retail outlets in the metropolis were sampled out of which 256 questionnaires were retrieved for the purpose of this analysis. The breakdown of the socio-economic characteristics of the sampled respondents showed that the gender distribution showed that 194 (75.78%) of the respondents were males, while 64 (24.22 %) were females. The average age of the sampled population was 33.70 years. The mixed method was employed for the achievement of the second objective of this study. Logistic Regression Model (LRM) was employed to test the hypothesis and the result revealed that the inclusion of the independent variables in the model increased the overall level of it accuracy. The overall significance revealed that the Model Chi- xxv Square, derived from the likelihood fitted is also accurate (X2 = 43.47, df=5, p>.05). The model chi-square value of 43.47 (approximately 44% ) was significant. Thus, the indication is that the model has a good fit in predicting the possibility of a fuel retail outlet being located in the core or peripheral zone of the metropolis as determined by the explanatory variables (the independent variables accounted for about 44% of possible factors which determined whether a fuel retail outlets is located either within the core or peripheral zones of the metropolis. The remaining 56% are factors not considered in the study). The result gotten from the in depth interview sessions corroborated the findings from the tested hypothesis. The third objective was to examine the effects which the supply chain technique employed (either vertically integrated model or third-party arrangement) has on the achievement of efficient and effective distribution of the products. In order to achieve this objective, all the 389 registered members of Petroleum Tanker Drivers (PTD) association who are members of the PTD in the metropolis were sampled, 265 (around 70%) of the distributed questionnaires were retrieved and used for the analysis. In depth interview sessions were also conducted with three different managers of the three major conglomerates in the downstream sector of the Nigerian petroleum sector. The result of one-way between subjects (ANOVA) which was conducted to compare differences in the management and performances of haulage services outsourced to the 3PLS and those run under VIM showed that there was a significant effect of ownership type on management performance (F (2,262) = 60.26, p<.05). The null hypothesis was therefore rejected while the alternate hypothesis was accepted. The findings from the interview sessions posted similar results. The fourth and final objective was to analyze the effect that the socio-economic attributes of the participants (haulers and managers of retail outlets) involved in the distribution of xxvi petroleum products has on the safe, efficient and cost-effective distribution of product and this was done through the use of descriptive statistics, inferential statistics and incisive analysis of the interview sessions. A total number of 265 (70%) out of the 389 registered members of Petroleum Tanker Driver Association (PTDA) participated in the study. Multiple regression analysis (MRA) was used to test this hypothesis. The result from the statistical analysis show that the use of stimulant, work condition, marital status and educational attainment/literacy level have joint influence on compliance (R2 = 0.31, F (4,260) = 29.72, p<.05). On the basis of the foregoing, the hypothesis is thus accepted. The result from the interview sessions confirmed the existence of strong relationship between the explanatory variables and the hypothetical dependant variable. The study recommended a review of the planning processes guiding the establishment of fuel retail outlets. The study also advocated that retailers should endeavour to have stronger control over the supply chain of their products this could done by investing more in VIM rather than outsourcing such functions to 3PLs. This will help in better business performances. Government agencies in charge of monitoring drug abuse among haulers are advised to be more proactive by the duo of prevention and punishment strategies. This should include advocacy campaign against drug abuse. Different ranges of punishments should also be meted out for individual haulers found culpable.
- Full Text:
- Date Issued: 2019
Application of computational methods in elucidating the isomerization step in the biosynthesis of coumarins
- Authors: Tshiwawa, Tendamudzimu
- Date: 2019
- Subjects: Coumarins , Isomerization , Biosynthesis , Organic compounds -- Synthesis , Cinnamic acid
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/67646 , vital:29124
- Description: The identity of the enzyme(s) responsible for the biosynthetic transformation of cinnamic acid derivatives to important, naturally occurring coumarins has yet to be established. This study constitutes a high-level theoretical analysis of the possibility that a recently reported molecular mechanism of the synthesis of coumarins from Baylis-Hillman adducts, may provide a viable model for three critical phases in the biosynthetic pathway Particular attention has been given to the first of these phases: i) E→Z isomerisation of the cinnamic acid precursor; ii) Cyclisation (lactonisation) to the hemi-acetal intermediate; and ii) Dehydration to afford the coumarin derivative. In order to accomplish this analysis, an enzyme capable, theoretically, of effecting this E→Z isomerisation required identification, and its potential involvement in the transformation mechanism explored. Combined Molecular Mechanics and high-level Quantum Mechanical/DFT calculations were used to access complementary models of appropriate complexes and relevant processes within the enzyme active sites of a range of eleven Chalcone Isomerase (CHI) enzyme candidates, the structures of which were downloaded from the Protein Data Bank. Detailed B3LYP/6-31+G(d,p) calculations have provided pictures of the relative populations of conformations within the ensemble of conformations available at normal temperatures. Conformations of several protonation states of cinnamic acid derivatives have been studied in this way, and the results obtained showed that coupled protonation and deprotonation of (E)-o-coumaric acid provides a viable approach to achieve the E→Z isomerization. In silico docking of the B3LYP/6-31+G(d,p) optimized (E)-o-coumaric acid derivatives in the active sites of each of the candidate CHI enzymes (CHI) revealed that (E)-o-coumaric acid fits well within the active sites of Medicago Sativa CHI crystallographic structures with 1FM8 showing best potential for not only accommodating (E)-o-coumaric acid , but also providing appropriate protein active site residues to effect the simultaneous protonation and deprotonation of the substrate , two residues being optimally placed to facilitate these critical processes. Further exploration of the chemical properties and qualities of selected CHI enzymes, undertaken using High Throughput Virtual Screening (HTVS), confirmed 1FM8 as a viable choice for further studies of the enzyme-catalysed E→Z isomerization of (E)-o-coumaric acid. A molecular dynamics study, performed to further evaluate the evolution of (E)-o-coumaric acid in the CHI active site over time, showed that the ligand in the 1FM8 active site is not only stable, but also that the desired protein-ligand interactions persist throughout the simulation period to facilitate the E→Z isomerization. An integrated molecular orbital and molecular mechanics (ONIOM) study of the 1FM8-(E)-o-coumaric acid complex, involving the direct protonation and deprotonation of the ligand by protein residues; has provided a plausible mechanism for the E → Z isomerization of (E)-o-coumaric acid within the 1FM8 active site; a transition state complex (with an activation energy of ca. 50 kCal.mol-1) has been located and its connection with both the (E)- and (Z)-o-coumaric acid isomer has been confirmed by Intrinsic Reaction Coordinate (IRC) calculations. More realistic models of the 1FM8-(E)-o-coumaric acid complex, with the inclusion of water solvent molecules, have been obtained at both the QM/MM and adaptive QM/MM levels which simulate the dynamic active site at the QM level. The results indicate that the simultaneous protonation and deprotonation of (E)-o-coumaric acid within the CHI enzyme is a water-mediated process – a conclusion consistent with similar reported processes. Visual inspection of the 1FM8-(Z)-o-coumaric acid complex reveals both the necessary orientation of the phenolic and carboxylic acid moieties of the (Z)-o-coumaric acid and the presence of appropriate, proximal active site residues with the potential to permit catalysis of the subsequent lactonisation and dehydration steps required to generate coumarin.
- Full Text:
- Date Issued: 2019
- Authors: Tshiwawa, Tendamudzimu
- Date: 2019
- Subjects: Coumarins , Isomerization , Biosynthesis , Organic compounds -- Synthesis , Cinnamic acid
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/67646 , vital:29124
- Description: The identity of the enzyme(s) responsible for the biosynthetic transformation of cinnamic acid derivatives to important, naturally occurring coumarins has yet to be established. This study constitutes a high-level theoretical analysis of the possibility that a recently reported molecular mechanism of the synthesis of coumarins from Baylis-Hillman adducts, may provide a viable model for three critical phases in the biosynthetic pathway Particular attention has been given to the first of these phases: i) E→Z isomerisation of the cinnamic acid precursor; ii) Cyclisation (lactonisation) to the hemi-acetal intermediate; and ii) Dehydration to afford the coumarin derivative. In order to accomplish this analysis, an enzyme capable, theoretically, of effecting this E→Z isomerisation required identification, and its potential involvement in the transformation mechanism explored. Combined Molecular Mechanics and high-level Quantum Mechanical/DFT calculations were used to access complementary models of appropriate complexes and relevant processes within the enzyme active sites of a range of eleven Chalcone Isomerase (CHI) enzyme candidates, the structures of which were downloaded from the Protein Data Bank. Detailed B3LYP/6-31+G(d,p) calculations have provided pictures of the relative populations of conformations within the ensemble of conformations available at normal temperatures. Conformations of several protonation states of cinnamic acid derivatives have been studied in this way, and the results obtained showed that coupled protonation and deprotonation of (E)-o-coumaric acid provides a viable approach to achieve the E→Z isomerization. In silico docking of the B3LYP/6-31+G(d,p) optimized (E)-o-coumaric acid derivatives in the active sites of each of the candidate CHI enzymes (CHI) revealed that (E)-o-coumaric acid fits well within the active sites of Medicago Sativa CHI crystallographic structures with 1FM8 showing best potential for not only accommodating (E)-o-coumaric acid , but also providing appropriate protein active site residues to effect the simultaneous protonation and deprotonation of the substrate , two residues being optimally placed to facilitate these critical processes. Further exploration of the chemical properties and qualities of selected CHI enzymes, undertaken using High Throughput Virtual Screening (HTVS), confirmed 1FM8 as a viable choice for further studies of the enzyme-catalysed E→Z isomerization of (E)-o-coumaric acid. A molecular dynamics study, performed to further evaluate the evolution of (E)-o-coumaric acid in the CHI active site over time, showed that the ligand in the 1FM8 active site is not only stable, but also that the desired protein-ligand interactions persist throughout the simulation period to facilitate the E→Z isomerization. An integrated molecular orbital and molecular mechanics (ONIOM) study of the 1FM8-(E)-o-coumaric acid complex, involving the direct protonation and deprotonation of the ligand by protein residues; has provided a plausible mechanism for the E → Z isomerization of (E)-o-coumaric acid within the 1FM8 active site; a transition state complex (with an activation energy of ca. 50 kCal.mol-1) has been located and its connection with both the (E)- and (Z)-o-coumaric acid isomer has been confirmed by Intrinsic Reaction Coordinate (IRC) calculations. More realistic models of the 1FM8-(E)-o-coumaric acid complex, with the inclusion of water solvent molecules, have been obtained at both the QM/MM and adaptive QM/MM levels which simulate the dynamic active site at the QM level. The results indicate that the simultaneous protonation and deprotonation of (E)-o-coumaric acid within the CHI enzyme is a water-mediated process – a conclusion consistent with similar reported processes. Visual inspection of the 1FM8-(Z)-o-coumaric acid complex reveals both the necessary orientation of the phenolic and carboxylic acid moieties of the (Z)-o-coumaric acid and the presence of appropriate, proximal active site residues with the potential to permit catalysis of the subsequent lactonisation and dehydration steps required to generate coumarin.
- Full Text:
- Date Issued: 2019
Application of some missing data techniques in estimating missing data in high blood pressure covariates
- Authors: Odeyemi, A. S
- Date: 2019
- Subjects: Missing observations (Statistics) Hypertension
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15189 , vital:40195
- Description: Cases recorded with high blood pressure are a major concern in both public and private hospitals. Adequate provision of health information of patients relating to high blood pressure in Eastern Cape Hospitals hinges so much on the outcome of statistical analysis results. The usual statistical methodologies become inadequate in handling statistical analysis of data collected due to incomplete patients’ information stored in the hospital database. From time to time, new methods are developed to address the problem of missing data. High blood pressure is linked to a lot of diseases such hypertension, cardiovascular disease, kidney disease and stroke. In this study, we developed a new method for addressing the problem of missing data in assessing model used for estimating missing values in terms of minimum errors(using RMSE, MAE, and SE) and goodness-of-fits(using 2 R and adjusted 2 R ) of this model and P-value. . The study compared six different methods: Original data (OD), Listwise deletion (LD), Mean imputations (MEI), Mean above (MA), and Mean above below(MAB) and two steps nearest neighbour (2-NN).The comparison was performed using original data set, and missing values at 5%, 10%, 20%, 30% were simulated on Framingham risk scores under MCAR and MAR simulation on BMI values given some assumptions. Five performance indicators were used to describe the model minimum errors and goodness of fit for all the methods. The results showed that the 2-NN is the best replacement method at lower levels (5% and10%) of missing values while MA and MEI performed best at higher levels(15% and 20%) of missing values. All comparison was based on estimates closest to those of the original data where no value was missing. MAR results showed that 2-NN performed better than LD,MA,MAB, and MEI at 5%,10%, and 20% levels of missing data in terms of absolute difference in p-value to original data.
- Full Text:
- Date Issued: 2019
- Authors: Odeyemi, A. S
- Date: 2019
- Subjects: Missing observations (Statistics) Hypertension
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15189 , vital:40195
- Description: Cases recorded with high blood pressure are a major concern in both public and private hospitals. Adequate provision of health information of patients relating to high blood pressure in Eastern Cape Hospitals hinges so much on the outcome of statistical analysis results. The usual statistical methodologies become inadequate in handling statistical analysis of data collected due to incomplete patients’ information stored in the hospital database. From time to time, new methods are developed to address the problem of missing data. High blood pressure is linked to a lot of diseases such hypertension, cardiovascular disease, kidney disease and stroke. In this study, we developed a new method for addressing the problem of missing data in assessing model used for estimating missing values in terms of minimum errors(using RMSE, MAE, and SE) and goodness-of-fits(using 2 R and adjusted 2 R ) of this model and P-value. . The study compared six different methods: Original data (OD), Listwise deletion (LD), Mean imputations (MEI), Mean above (MA), and Mean above below(MAB) and two steps nearest neighbour (2-NN).The comparison was performed using original data set, and missing values at 5%, 10%, 20%, 30% were simulated on Framingham risk scores under MCAR and MAR simulation on BMI values given some assumptions. Five performance indicators were used to describe the model minimum errors and goodness of fit for all the methods. The results showed that the 2-NN is the best replacement method at lower levels (5% and10%) of missing values while MA and MEI performed best at higher levels(15% and 20%) of missing values. All comparison was based on estimates closest to those of the original data where no value was missing. MAR results showed that 2-NN performed better than LD,MA,MAB, and MEI at 5%,10%, and 20% levels of missing data in terms of absolute difference in p-value to original data.
- Full Text:
- Date Issued: 2019
Applying anthropological perspectives in criminal procedures involving murder in Port Elizabeth, 2000-2016
- Authors: Thornton, Jessica Leigh
- Date: 2019
- Subjects: Criminal procedures
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44688 , vital:38161
- Description: With the spike of annual reported murders in South Africa, the country is continuing to climb the global rank of the world’s most violent countries. In 2016 alone, there were over nineteen thousand reported murders, equalling over fifty murders per day, with the Eastern Cape holding position as the province with the highest murder rate. Studies indicate that Port Elizabeth is the hardest hit by crime, adding up to 60% of all reported crimes in the province and despite the use of a ‘catch and convict’ only approach in criminal proceedings, violence and crime are still highly prevalent. Thus, overall the situation suggests that it may be beyond law enforcement control and even though the South African Police Service have taken some progressive steps in reforming procedures, generally, these have been too little and too late, as the reforms introduced are piecemeal and crisis driven. This thesis, therefore, proposes that additional approaches may be needed to improve investigations of the most pernicious crimes. Here, the focus is on the role of culture and social life in ‘murder-scapes’ with a critical contribution of the ‘habitus’ of murder allowing for the meaningful engagement with criminal acts, policing, sentencing, imprisonment and probation. In this regard, perspectives drawn from anthropology can possibly assist law enforcement officials in their steps of investigating a murder by providing a more ethnographic, holistic and integrated narrative in all areas of a criminal proceeding. An efficacious and constructive interpretation of the different subcultures crime scene processing, profiles development, testimony documentation and participation production with the police force and task teams can assist in redirecting and reappraising current practises that prove incompetent. That is, in attempting to review the current procedures conducted by law enforcers to identify how and where anthropological and ethnographical knowledge can be applied and successfully utilised, an assessment may aid officials in better investigative practises which could have implications for wider lenses making use of action, investigation, containment, prevention and rehabilitation. By advancing a deep understanding of the issue of murder in the South African context, implications for a wider, equally modernising and equally troubled society in the global South can be inferred.
- Full Text:
- Date Issued: 2019
- Authors: Thornton, Jessica Leigh
- Date: 2019
- Subjects: Criminal procedures
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44688 , vital:38161
- Description: With the spike of annual reported murders in South Africa, the country is continuing to climb the global rank of the world’s most violent countries. In 2016 alone, there were over nineteen thousand reported murders, equalling over fifty murders per day, with the Eastern Cape holding position as the province with the highest murder rate. Studies indicate that Port Elizabeth is the hardest hit by crime, adding up to 60% of all reported crimes in the province and despite the use of a ‘catch and convict’ only approach in criminal proceedings, violence and crime are still highly prevalent. Thus, overall the situation suggests that it may be beyond law enforcement control and even though the South African Police Service have taken some progressive steps in reforming procedures, generally, these have been too little and too late, as the reforms introduced are piecemeal and crisis driven. This thesis, therefore, proposes that additional approaches may be needed to improve investigations of the most pernicious crimes. Here, the focus is on the role of culture and social life in ‘murder-scapes’ with a critical contribution of the ‘habitus’ of murder allowing for the meaningful engagement with criminal acts, policing, sentencing, imprisonment and probation. In this regard, perspectives drawn from anthropology can possibly assist law enforcement officials in their steps of investigating a murder by providing a more ethnographic, holistic and integrated narrative in all areas of a criminal proceeding. An efficacious and constructive interpretation of the different subcultures crime scene processing, profiles development, testimony documentation and participation production with the police force and task teams can assist in redirecting and reappraising current practises that prove incompetent. That is, in attempting to review the current procedures conducted by law enforcers to identify how and where anthropological and ethnographical knowledge can be applied and successfully utilised, an assessment may aid officials in better investigative practises which could have implications for wider lenses making use of action, investigation, containment, prevention and rehabilitation. By advancing a deep understanding of the issue of murder in the South African context, implications for a wider, equally modernising and equally troubled society in the global South can be inferred.
- Full Text:
- Date Issued: 2019
Bolvedere: a scalable network flow threat analysis system
- Authors: Herbert, Alan
- Date: 2019
- Subjects: Bolvedere (Computer network analysis system) , Computer networks -- Scalability , Computer networks -- Measurement , Computer networks -- Security measures , Telecommunication -- Traffic -- Measurement
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/71557 , vital:29873
- Description: Since the advent of the Internet, and its public availability in the late 90’s, there have been significant advancements to network technologies and thus a significant increase of the bandwidth available to network users, both human and automated. Although this growth is of great value to network users, it has led to an increase in malicious network-based activities and it is theorized that, as more services become available on the Internet, the volume of such activities will continue to grow. Because of this, there is a need to monitor, comprehend, discern, understand and (where needed) respond to events on networks worldwide. Although this line of thought is simple in its reasoning, undertaking such a task is no small feat. Full packet analysis is a method of network surveillance that seeks out specific characteristics within network traffic that may tell of malicious activity or anomalies in regular network usage. It is carried out within firewalls and implemented through packet classification. In the context of the networks that make up the Internet, this form of packet analysis has become infeasible, as the volume of traffic introduced onto these networks every day is so large that there are simply not enough processing resources to perform such a task on every packet in real time. One could combat this problem by performing post-incident forensics; archiving packets and processing them later. However, as one cannot process all incoming packets, the archive will eventually run out of space. Full packet analysis is also hindered by the fact that some existing, commonly-used solutions are designed around a single host and single thread of execution, an outdated approach that is far slower than necessary on current computing technology. This research explores the conceptual design and implementation of a scalable network traffic analysis system named Bolvedere. Analysis performed by Bolvedere simply asks whether the existence of a connection, coupled with its associated metadata, is enough to conclude something meaningful about that connection. This idea draws away from the traditional processing of every single byte in every single packet monitored on a network link (Deep Packet Inspection) through the concept of working with connection flows. Bolvedere performs its work by leveraging the NetFlow version 9 and IPFIX protocols, but is not limited to these. It is implemented using a modular approach that allows for either complete execution of the system on a single host or the horizontal scaling out of subsystems on multiple hosts. The use of multiple hosts is achieved through the implementation of Zero Message Queue (ZMQ). This allows for Bolvedre to horizontally scale out, which results in an increase in processing resources and thus an increase in analysis throughput. This is due to ease of interprocess communications provided by ZMQ. Many underlying mechanisms in Bolvedere have been automated. This is intended to make the system more userfriendly, as the user need only tell Bolvedere what information they wish to analyse, and the system will then rebuild itself in order to achieve this required task. Bolvedere has also been hardware-accelerated through the use of Field-Programmable Gate Array (FPGA) technologies, which more than doubled the total throughput of the system.
- Full Text:
- Date Issued: 2019
- Authors: Herbert, Alan
- Date: 2019
- Subjects: Bolvedere (Computer network analysis system) , Computer networks -- Scalability , Computer networks -- Measurement , Computer networks -- Security measures , Telecommunication -- Traffic -- Measurement
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/71557 , vital:29873
- Description: Since the advent of the Internet, and its public availability in the late 90’s, there have been significant advancements to network technologies and thus a significant increase of the bandwidth available to network users, both human and automated. Although this growth is of great value to network users, it has led to an increase in malicious network-based activities and it is theorized that, as more services become available on the Internet, the volume of such activities will continue to grow. Because of this, there is a need to monitor, comprehend, discern, understand and (where needed) respond to events on networks worldwide. Although this line of thought is simple in its reasoning, undertaking such a task is no small feat. Full packet analysis is a method of network surveillance that seeks out specific characteristics within network traffic that may tell of malicious activity or anomalies in regular network usage. It is carried out within firewalls and implemented through packet classification. In the context of the networks that make up the Internet, this form of packet analysis has become infeasible, as the volume of traffic introduced onto these networks every day is so large that there are simply not enough processing resources to perform such a task on every packet in real time. One could combat this problem by performing post-incident forensics; archiving packets and processing them later. However, as one cannot process all incoming packets, the archive will eventually run out of space. Full packet analysis is also hindered by the fact that some existing, commonly-used solutions are designed around a single host and single thread of execution, an outdated approach that is far slower than necessary on current computing technology. This research explores the conceptual design and implementation of a scalable network traffic analysis system named Bolvedere. Analysis performed by Bolvedere simply asks whether the existence of a connection, coupled with its associated metadata, is enough to conclude something meaningful about that connection. This idea draws away from the traditional processing of every single byte in every single packet monitored on a network link (Deep Packet Inspection) through the concept of working with connection flows. Bolvedere performs its work by leveraging the NetFlow version 9 and IPFIX protocols, but is not limited to these. It is implemented using a modular approach that allows for either complete execution of the system on a single host or the horizontal scaling out of subsystems on multiple hosts. The use of multiple hosts is achieved through the implementation of Zero Message Queue (ZMQ). This allows for Bolvedre to horizontally scale out, which results in an increase in processing resources and thus an increase in analysis throughput. This is due to ease of interprocess communications provided by ZMQ. Many underlying mechanisms in Bolvedere have been automated. This is intended to make the system more userfriendly, as the user need only tell Bolvedere what information they wish to analyse, and the system will then rebuild itself in order to achieve this required task. Bolvedere has also been hardware-accelerated through the use of Field-Programmable Gate Array (FPGA) technologies, which more than doubled the total throughput of the system.
- Full Text:
- Date Issued: 2019
Boundary-crossing learning in agricultural learning systems: formative interventions for water and seed provision in southern Africa
- Authors: Pesanayi, Victor Tichaona
- Date: 2019
- Subjects: Agriultural extension work -- Africa, Southern , Agriultural colleges -- Africa, Southern , Farmers -- Education -- Africa, Southern , Agriculture and state -- Africa, Southern , Sustainable agriculture -- Africa, Southern
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/94067 , vital:30997
- Description: This research was conducted in the Amathole rural district of the Eastern Cape Province of South Africa, and in Zvishavane and Zhombe rural districts of the Midlands Province of Zimbabwe over a period of four years. In the first two years of this period I was involved in co-engaged boundary-crossing expansive learning processes with research participants from agricultural education (agricultural college lecturers, principals and university lecturers), extension services (extension officers, advisors and workers), small-scale farmers and a local economic development (LED) agency as agricultural learning activity systems. The latter was applicable only to the South African nested case while the rest applied to both country nested cases. The study focusses on the boundary-crossing learning of sustainable agricultural water relevant for small-scale farming contexts under rain-fed and climate constrained conditions with specific attention to rainwater harvesting and conservation and climate-adaptive seed. The study employed cultural-historical activity theory (CHAT) and developmental work research methodology developed by Yrjö Engeström and his colleagues at the Centre for Researching Activity Development and Learning (CRADLE) at the University of Helsinki in Finland. The study was guided by three objectives. The first objective was to find out how the different groups represented across the activity systems listed above learn together to mediate and communicate sustainable agricultural water and seed saving. To address this objective I conducted focus groups and interviews with key informants, made observations and analysed documents. The second objective was to explore and document the socio-ecological histories of rainwater harvesting and conservation, locally-adaptive seed systems and associated value chains, and socio-cultural histories of agricultural learning systems in the context of small-scale farming using historical and ethnographic research techniques. The third objective was to understand how learning, curriculum innovation and mediation tools for agricultural extension education and farmer training that can expand learning of rainwater harvesting and conservation sustainable practices for improved local agricultural water and climate-adaptive non-formal seed systems in agricultural education and small-scale farmer activity systems could be co-generated. This third objective constituted the boundary-crossing expansive learning that emerged from change laboratory workshops carefully designed to explore the common water for food object across the different but related activity systems. The study reveals historically-persisting tensions and contradictions in the work of agricultural college lecturers, small-scale farmers and extension workers that limit their ability to work together relationally leaving them operating in isolated ‘silos’. The industrially-driven agricultural college curriculum promoting conventional irrigated agriculture conflicted with the college’s objective of producing extension workers who will work with resource-poor small-scale farmers in rain-fed farming systems. This conflict was aggravated by the work of extension workers who had little to no knowledge regarding how to support small-scale farmers facing persistent drought and consequent crop failure due to poor and erratic rainfall. At the same time extension services promoting genetically modified (GMO) seed in South Africa were in conflict with some small-scale farmers’ demands for seed that was adapted to their changing climate and their ability to operate independently with access to and ownership of land. This study shows that the work of agricultural colleges and extension services often defeats its intended structural objectives due to historically-constituted power relations around knowledge. This study has demonstrated the effectiveness of co-generative formative interventions in boundary-crossing scenarios in learning network contexts for expansion of activity in farming communities, agricultural colleges and extension services, with emphasis of transformed activity towards engaging a collective object of rainwater harvesting and conservation for more sustainable agriculture and poverty alleviation. The study shows that diverse combinations of change practice courses, change laboratories, demonstration sites and media engagements as mediation processes in the context of learning networks strengthened the possibility for boundary-crossing expansive learning across activity systems of agricultural college lecturers, smallholder farmers, extension workers and local economic development agency facilitators. Three of the five mediation processes emerged out of the formative intervention processes in both the South African and Zimbabwean case studies while two were not realised in the Zimbabwean case study, namely the change practice course and media engagements, due to different formative intervention conditions, inadequate time and resources. Boundary-crossing was enabled by a variety of actions including understanding and identifying with the context of the other (i.e. developing empathy) as a result of change laboratory workshops that also ensured confrontation with relational contradictions. The study concludes that it is possible for historically-constituted contradictions around water for food to be resolved when participants from different agricultural learning systems co-engage as equals in boundary-crossing change laboratory fora mediated by appropriate tools and processes. The study contributes to innovation in agricultural learning systems in southern Africa, in particular to means of engaging across boundaries of previously largely disconnected activity systems in ways that benefit smallholder farmers who have previously been marginalised from mainstream agricultural learning systems.
- Full Text:
- Date Issued: 2019
- Authors: Pesanayi, Victor Tichaona
- Date: 2019
- Subjects: Agriultural extension work -- Africa, Southern , Agriultural colleges -- Africa, Southern , Farmers -- Education -- Africa, Southern , Agriculture and state -- Africa, Southern , Sustainable agriculture -- Africa, Southern
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/94067 , vital:30997
- Description: This research was conducted in the Amathole rural district of the Eastern Cape Province of South Africa, and in Zvishavane and Zhombe rural districts of the Midlands Province of Zimbabwe over a period of four years. In the first two years of this period I was involved in co-engaged boundary-crossing expansive learning processes with research participants from agricultural education (agricultural college lecturers, principals and university lecturers), extension services (extension officers, advisors and workers), small-scale farmers and a local economic development (LED) agency as agricultural learning activity systems. The latter was applicable only to the South African nested case while the rest applied to both country nested cases. The study focusses on the boundary-crossing learning of sustainable agricultural water relevant for small-scale farming contexts under rain-fed and climate constrained conditions with specific attention to rainwater harvesting and conservation and climate-adaptive seed. The study employed cultural-historical activity theory (CHAT) and developmental work research methodology developed by Yrjö Engeström and his colleagues at the Centre for Researching Activity Development and Learning (CRADLE) at the University of Helsinki in Finland. The study was guided by three objectives. The first objective was to find out how the different groups represented across the activity systems listed above learn together to mediate and communicate sustainable agricultural water and seed saving. To address this objective I conducted focus groups and interviews with key informants, made observations and analysed documents. The second objective was to explore and document the socio-ecological histories of rainwater harvesting and conservation, locally-adaptive seed systems and associated value chains, and socio-cultural histories of agricultural learning systems in the context of small-scale farming using historical and ethnographic research techniques. The third objective was to understand how learning, curriculum innovation and mediation tools for agricultural extension education and farmer training that can expand learning of rainwater harvesting and conservation sustainable practices for improved local agricultural water and climate-adaptive non-formal seed systems in agricultural education and small-scale farmer activity systems could be co-generated. This third objective constituted the boundary-crossing expansive learning that emerged from change laboratory workshops carefully designed to explore the common water for food object across the different but related activity systems. The study reveals historically-persisting tensions and contradictions in the work of agricultural college lecturers, small-scale farmers and extension workers that limit their ability to work together relationally leaving them operating in isolated ‘silos’. The industrially-driven agricultural college curriculum promoting conventional irrigated agriculture conflicted with the college’s objective of producing extension workers who will work with resource-poor small-scale farmers in rain-fed farming systems. This conflict was aggravated by the work of extension workers who had little to no knowledge regarding how to support small-scale farmers facing persistent drought and consequent crop failure due to poor and erratic rainfall. At the same time extension services promoting genetically modified (GMO) seed in South Africa were in conflict with some small-scale farmers’ demands for seed that was adapted to their changing climate and their ability to operate independently with access to and ownership of land. This study shows that the work of agricultural colleges and extension services often defeats its intended structural objectives due to historically-constituted power relations around knowledge. This study has demonstrated the effectiveness of co-generative formative interventions in boundary-crossing scenarios in learning network contexts for expansion of activity in farming communities, agricultural colleges and extension services, with emphasis of transformed activity towards engaging a collective object of rainwater harvesting and conservation for more sustainable agriculture and poverty alleviation. The study shows that diverse combinations of change practice courses, change laboratories, demonstration sites and media engagements as mediation processes in the context of learning networks strengthened the possibility for boundary-crossing expansive learning across activity systems of agricultural college lecturers, smallholder farmers, extension workers and local economic development agency facilitators. Three of the five mediation processes emerged out of the formative intervention processes in both the South African and Zimbabwean case studies while two were not realised in the Zimbabwean case study, namely the change practice course and media engagements, due to different formative intervention conditions, inadequate time and resources. Boundary-crossing was enabled by a variety of actions including understanding and identifying with the context of the other (i.e. developing empathy) as a result of change laboratory workshops that also ensured confrontation with relational contradictions. The study concludes that it is possible for historically-constituted contradictions around water for food to be resolved when participants from different agricultural learning systems co-engage as equals in boundary-crossing change laboratory fora mediated by appropriate tools and processes. The study contributes to innovation in agricultural learning systems in southern Africa, in particular to means of engaging across boundaries of previously largely disconnected activity systems in ways that benefit smallholder farmers who have previously been marginalised from mainstream agricultural learning systems.
- Full Text:
- Date Issued: 2019
Centralising a counter public: an ethnographic study of the interpretation of mainstream news media by young adults in Joza
- Authors: Ponono, Mvuzo
- Date: 2019
- Subjects: African National Congress Mass media -- Political aspects -- South Africa Press and politics -- South Africa , South Africa -- Politics and government -- 21st century Zuma, Jacob -- Political and social views , Political corruption -- 21st century Elections -- South Africa Voting -- South Africa Misconduct in office -- South Africa Abuse of administrative power -- South Africa Young adults -- Political activity -- South Africa -- Grahamstown Young adults -- Politics and government
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/65033 , vital:28655
- Description: The 2014 national general elections were characterised by a cloud of scandal hanging over the ANC, and the ANC president Jacob Zuma. The biggest and darkest cloud was the Nkandla scandal. Owing to a reported R246 million spent by the state to refurbish his private home, the president stood accused of wasteful expenditure and financial irregularity. In a country reeling from the continued effects of apartheid, which include high unemployment and poverty, the scandal was a bombshell. According to a vocal and often adversarial mainstream media sphere, the ANC went into those elections with an albatross around its neck. The dominant thought was that the ruling party would suffer a heavy loss of votes. This outcome did not materialise. The ANC lost a marginal share of its previous vote. Mainstream media and civil society were confounded. What had happened? Why had poor black South Africans continued to vote for a party that was obviously in breach of the constitutional order? Against the mismatch between what was predicted or purported and the outcome, this study investigates how young people in the township of Joza, Grahamstown, interpreted one of the biggest political scandals in South Africa’s fledgling democracy. Using a combination of subaltern studies, counter public sphere and audience study, the research looks into the interpretation of a mainstream media scandal that was supposed to diminish the chances of the ANC retaining power, but, instead, barely dented its majority. Through a combination of interviews and participant observation, the study found that young people in the township of Joza demonstrated that they chose to ignore the messages about the corruption of the ANC. The data suggests that they did so, not because of overt racial solidarity, but due to the fact that in a context of high inequality, and continued limitations on economic emancipation, the party shone brightly as a vehicle for economic development. Overall, the study argues that the seemingly dubious undertaking to continue with the ANC is a calculated decision that makes sense when viewed within a given socio-economic context.
- Full Text:
- Date Issued: 2019
- Authors: Ponono, Mvuzo
- Date: 2019
- Subjects: African National Congress Mass media -- Political aspects -- South Africa Press and politics -- South Africa , South Africa -- Politics and government -- 21st century Zuma, Jacob -- Political and social views , Political corruption -- 21st century Elections -- South Africa Voting -- South Africa Misconduct in office -- South Africa Abuse of administrative power -- South Africa Young adults -- Political activity -- South Africa -- Grahamstown Young adults -- Politics and government
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/65033 , vital:28655
- Description: The 2014 national general elections were characterised by a cloud of scandal hanging over the ANC, and the ANC president Jacob Zuma. The biggest and darkest cloud was the Nkandla scandal. Owing to a reported R246 million spent by the state to refurbish his private home, the president stood accused of wasteful expenditure and financial irregularity. In a country reeling from the continued effects of apartheid, which include high unemployment and poverty, the scandal was a bombshell. According to a vocal and often adversarial mainstream media sphere, the ANC went into those elections with an albatross around its neck. The dominant thought was that the ruling party would suffer a heavy loss of votes. This outcome did not materialise. The ANC lost a marginal share of its previous vote. Mainstream media and civil society were confounded. What had happened? Why had poor black South Africans continued to vote for a party that was obviously in breach of the constitutional order? Against the mismatch between what was predicted or purported and the outcome, this study investigates how young people in the township of Joza, Grahamstown, interpreted one of the biggest political scandals in South Africa’s fledgling democracy. Using a combination of subaltern studies, counter public sphere and audience study, the research looks into the interpretation of a mainstream media scandal that was supposed to diminish the chances of the ANC retaining power, but, instead, barely dented its majority. Through a combination of interviews and participant observation, the study found that young people in the township of Joza demonstrated that they chose to ignore the messages about the corruption of the ANC. The data suggests that they did so, not because of overt racial solidarity, but due to the fact that in a context of high inequality, and continued limitations on economic emancipation, the party shone brightly as a vehicle for economic development. Overall, the study argues that the seemingly dubious undertaking to continue with the ANC is a calculated decision that makes sense when viewed within a given socio-economic context.
- Full Text:
- Date Issued: 2019
Challenges faced by grandparents in caring for their grandchildren in Mdlankomo location, Libode, Eastern Cape
- Authors: Soganga, Aseza
- Date: 2019
- Subjects: Grandparents as parents Grandchildren -- Care
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/16188 , vital:40692
- Description: The study aimed to investigate the challenges that older grandparents face in caring for their grandchildren in Mdlankomo Location, Libode, Eastern Cape. The study intended to achieve three (3) objectives: (i) to establish factors that make caregiving of children by their grandparents challenging, (ii) to establish resources that grandparents need to care for their grandchildren and (iii) to establish the availability of resources required by the grandparents to care for their grandchildren and its possible gaps. The study utilized qualitative research approach, and date collection methods used were in-depth interviews, focus group discussion and key informant method. The number of participants was 34 in total consisting of 23 grandparents and 11 key informants. The findings of the study showed that death of children’s own parents; cultural expectations, youth unemployment, abdication of parental responsibilities, youth unemployment, and carelessness of biological parents were the major reasons for grandparents to care for their grandchildren. The study findings also revealed that grandparents in this caregiving experience both benefits and barriers. The findings further revealed that there are gaps in welfare services, medical services and education. Therefore, the researcher recommended that, those in power should be interested, eager and inquisitive enough about certain aspects that need attention in caregiving of children by their grandparents.
- Full Text:
- Date Issued: 2019
- Authors: Soganga, Aseza
- Date: 2019
- Subjects: Grandparents as parents Grandchildren -- Care
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/16188 , vital:40692
- Description: The study aimed to investigate the challenges that older grandparents face in caring for their grandchildren in Mdlankomo Location, Libode, Eastern Cape. The study intended to achieve three (3) objectives: (i) to establish factors that make caregiving of children by their grandparents challenging, (ii) to establish resources that grandparents need to care for their grandchildren and (iii) to establish the availability of resources required by the grandparents to care for their grandchildren and its possible gaps. The study utilized qualitative research approach, and date collection methods used were in-depth interviews, focus group discussion and key informant method. The number of participants was 34 in total consisting of 23 grandparents and 11 key informants. The findings of the study showed that death of children’s own parents; cultural expectations, youth unemployment, abdication of parental responsibilities, youth unemployment, and carelessness of biological parents were the major reasons for grandparents to care for their grandchildren. The study findings also revealed that grandparents in this caregiving experience both benefits and barriers. The findings further revealed that there are gaps in welfare services, medical services and education. Therefore, the researcher recommended that, those in power should be interested, eager and inquisitive enough about certain aspects that need attention in caregiving of children by their grandparents.
- Full Text:
- Date Issued: 2019
Challenges of subsistence farming in South Africa: a case study of Emjkweni village in Eastern Cape Province
- Authors: Mngqinya, Yoliswa
- Date: 2019
- Subjects: Subsistence agriculture
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44553 , vital:38142
- Description: Subsistence agriculture plays an important role in the livelihood of Africa’s rural population. Yet in many countries like South Africa, rather than seeing an upward projection of food production with an almost natural shift towards commercialising household production of food, the state of rural agriculture continues to go into decline. Since the advent of South Africa’s new dawn of democracy in 1994, agriculture has been the priority of government for the advancement of subsistence economy and rural development in rural communities. But progress in making a vibrant sustainable economy out of subsistence farming has remained stymied. At a time when there is a need to significantly increase the productivity of subsistence/smallholder agriculture and ensure long-term food security, rural subsistence farmers in the former bread basket of the Eastern Cape Province, have abandoned crop production. Characteristic of contemporary Eastern Cape’s rural landscape is the sight of large tracts of farm land lying uncultivated. Amidst a raging debate in South Africa on land the merits of the debate remain silent in the face of visibly idle crop land. This study has attempted to make a small incision into a growing body of knowledge on land reform with a view to and laying bare current challenges that keep rural folk out of the field, notwithstanding availability of land. Adopting multi-level research techniques, a purposive sample of 83 village respondents in eMjikweni was selected. Through a combination of face-to-face interviews using an open-ended interview instrument; focus group discussions and case studies, information was extracted from the sample to understand the current challenges of subsistence farming that make for poor household crop production, intensified dependence on social grants for income and growing food insecurity. Despite a conducive policy environment, the study findings suggest that as long as political will is absent, the formula for agrarian reform will remain incorrect, further entrenching rural poverty. As an exercise in social enquiry, the study employed a combination of quantitative and qualitative data analysis methods, while being careful to note how methodology impacts on the ability of respondents to narrate their lived experience, which, carefully crafted, can be valuable catalysts to a more bottom-up approach to rural development, sustainable agriculture and enhanced food security in the Eastern Cape. The merit of this study in making the said incision into a growing body of information on land reform is that it provides a glimpse into the life of a rural subsistence farmer. With the launch of the Presidential Panel Report on Land Reform (2019) a few days ago, the voice and experience of those who bear the brunt of land reform becomes critical. They are a people facing enormous challenges to restoring subsistence agriculture as a vibrant contributor to food security at household level and to reduced dependency on the state for its livelihood. They are a people who once created the “bread basket” of the Eastern Cape Province with a vibrant agricultural economy. They are a people who raise children to form part of the significant statistics of migrants to the economic hubs of Gauteng Province in particular in search of employment. They are a people who contribute significantly to the growing numbers of people dependent on the state for social grants. They are a people central to solving land reform for a better South Africa. It is based on their stories that this study’s findings argue for the revitalisation of the subsistence economies of rural communities which recognises the deeply entrenched socio-economic and geo-spatial transformations over time that make it quite complex to return to a past utopia. It is the premise of this thesis that the smallholder and subsistence agricultural sector has the potential to create job opportunities and promote local economic development in rural communities, which in turn would mitigate the triple challenge of poverty, unemployment and inequality facing South African society.
- Full Text:
- Date Issued: 2019
- Authors: Mngqinya, Yoliswa
- Date: 2019
- Subjects: Subsistence agriculture
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44553 , vital:38142
- Description: Subsistence agriculture plays an important role in the livelihood of Africa’s rural population. Yet in many countries like South Africa, rather than seeing an upward projection of food production with an almost natural shift towards commercialising household production of food, the state of rural agriculture continues to go into decline. Since the advent of South Africa’s new dawn of democracy in 1994, agriculture has been the priority of government for the advancement of subsistence economy and rural development in rural communities. But progress in making a vibrant sustainable economy out of subsistence farming has remained stymied. At a time when there is a need to significantly increase the productivity of subsistence/smallholder agriculture and ensure long-term food security, rural subsistence farmers in the former bread basket of the Eastern Cape Province, have abandoned crop production. Characteristic of contemporary Eastern Cape’s rural landscape is the sight of large tracts of farm land lying uncultivated. Amidst a raging debate in South Africa on land the merits of the debate remain silent in the face of visibly idle crop land. This study has attempted to make a small incision into a growing body of knowledge on land reform with a view to and laying bare current challenges that keep rural folk out of the field, notwithstanding availability of land. Adopting multi-level research techniques, a purposive sample of 83 village respondents in eMjikweni was selected. Through a combination of face-to-face interviews using an open-ended interview instrument; focus group discussions and case studies, information was extracted from the sample to understand the current challenges of subsistence farming that make for poor household crop production, intensified dependence on social grants for income and growing food insecurity. Despite a conducive policy environment, the study findings suggest that as long as political will is absent, the formula for agrarian reform will remain incorrect, further entrenching rural poverty. As an exercise in social enquiry, the study employed a combination of quantitative and qualitative data analysis methods, while being careful to note how methodology impacts on the ability of respondents to narrate their lived experience, which, carefully crafted, can be valuable catalysts to a more bottom-up approach to rural development, sustainable agriculture and enhanced food security in the Eastern Cape. The merit of this study in making the said incision into a growing body of information on land reform is that it provides a glimpse into the life of a rural subsistence farmer. With the launch of the Presidential Panel Report on Land Reform (2019) a few days ago, the voice and experience of those who bear the brunt of land reform becomes critical. They are a people facing enormous challenges to restoring subsistence agriculture as a vibrant contributor to food security at household level and to reduced dependency on the state for its livelihood. They are a people who once created the “bread basket” of the Eastern Cape Province with a vibrant agricultural economy. They are a people who raise children to form part of the significant statistics of migrants to the economic hubs of Gauteng Province in particular in search of employment. They are a people who contribute significantly to the growing numbers of people dependent on the state for social grants. They are a people central to solving land reform for a better South Africa. It is based on their stories that this study’s findings argue for the revitalisation of the subsistence economies of rural communities which recognises the deeply entrenched socio-economic and geo-spatial transformations over time that make it quite complex to return to a past utopia. It is the premise of this thesis that the smallholder and subsistence agricultural sector has the potential to create job opportunities and promote local economic development in rural communities, which in turn would mitigate the triple challenge of poverty, unemployment and inequality facing South African society.
- Full Text:
- Date Issued: 2019
Charting freedom: inequality beliefs, preferences for redistribution, and distributive social policy in contemporary South Africa
- Authors: Roberts, Benjamin J
- Date: 2019
- Subjects: South Africa -- Economic conditions South Africa -- Economic policy South Africa -- Social policy , Democracy -- Economic conditions -- South Africa Race discrimination -- South Africa Poverty -- South Africa Equality -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64999 , vital:28644
- Description: While the transition to democracy in South Africa extended civil and political rights and freedoms to all South Africans, there has been disagreement over the preferred nature and scope of social rights within post-apartheid society, reflecting debates over the trajectory of economic policy. Appreciable developmental gains have been made by the state over the last quarter-century, yet the challenges of poverty, unemployment and inequality persist, coupled with mounting popular discontent with the pace of transformation and political accountability. This has led to fundamental questions about social justice, restitution, and the kind of society we wish to promote. Appeals for a more inclusive, transformative social policy have also emerged, arguing that a wider vision of society is required involving multiple government responsibilities and informed by an ethic of equality and social solidarity. Against this background, in this thesis I study the views of the South African public towards economic inequality, general preferences for government-led redistribution, as well as support for social policies intended to promote racial and economic transformation. The research has been guided by several overarching questions: To what extent do South Africans share common general beliefs about material inequality? Does the public exhibit a preference for government redistribution in principle? And how unified or polarised are South Africans in their support for specific redress policies in the country? Responding to these questions has been achieved by drawing on unique, nationally representative data from the South African Social Attitudes Survey (SASAS), which has enabled me to chart social attitudes over a period of almost fifteen years between late 2003 and early 2017. Use has also been made of social citizenship as a guiding conceptual framework to understanding social policy predispositions and analysing attitudinal change. The results demonstrate that the public is united in its awareness of and deep concern about economic inequality. Since the early 2000s, a significant majority has consistently expressed the view that the income gap in the country is too large, articulated a strong preference for a more equitable social structure, and acknowledged the class and social tensions that economic inequality has produced. There is also a preference for a narrowing of earnings disparities, a more generous minimum wage, and regulatory limits on executive pay. While this suggests a desire for fair and legitimate remuneration, the analysis also reveals that South Africans are willing to tolerate fairly high levels of inequality. Nonetheless, these beliefs are generally interpreted as a desire for a more equitable and fair society. This preference for change is reflected in a fairly strong belief that government should assume responsibility for reducing material disparities. One’s social position, mobility history, awareness of inequality, political leaning and racial attitudes all have a bearing on how weak and strong this predisposition is, but the normative demand for political redistribution remains fairly widely shared irrespective of these individual traits. Greater polarisation is however evident with respect to redistributive social policy, especially measures designed to overcome historical racial injustice (affirmative action, sports quotas, and land reform). These intergroup differences converge considerably when referring to class-based policy measures. One surprising finding is the evidence that South Africa’s youngest generation, the so-called ‘Born Frees’, tend to adopt a similar predisposition to redress policy as older generations, thus confounding expectations of a post-apartheid value change. I conclude by arguing that there seems to be a firmer basis for a social compact about preferences for interventions designed to produce a more just society than is typically assumed. Intractably high levels of economic inequality during the country’s first quarter-century of democracy is resulting in a growing recognition of the need for a stronger policy emphasis on economic inequality in South Africa over coming decades if the vision enshrined in the Freedom Charter and the Constitution is to be realised. South Africans may not be able to fully agree about the specific elements that constitute a socially just response to economic inequality. Yet, the common identification of and concern with redressable injustice, coupled with a broad-based commitment to government redistribution and classbased social policies, could serve as a foundation on which to rekindle the solidaristic spirit of 1994 and forge progress towards a more equitable society.
- Full Text:
- Date Issued: 2019
- Authors: Roberts, Benjamin J
- Date: 2019
- Subjects: South Africa -- Economic conditions South Africa -- Economic policy South Africa -- Social policy , Democracy -- Economic conditions -- South Africa Race discrimination -- South Africa Poverty -- South Africa Equality -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64999 , vital:28644
- Description: While the transition to democracy in South Africa extended civil and political rights and freedoms to all South Africans, there has been disagreement over the preferred nature and scope of social rights within post-apartheid society, reflecting debates over the trajectory of economic policy. Appreciable developmental gains have been made by the state over the last quarter-century, yet the challenges of poverty, unemployment and inequality persist, coupled with mounting popular discontent with the pace of transformation and political accountability. This has led to fundamental questions about social justice, restitution, and the kind of society we wish to promote. Appeals for a more inclusive, transformative social policy have also emerged, arguing that a wider vision of society is required involving multiple government responsibilities and informed by an ethic of equality and social solidarity. Against this background, in this thesis I study the views of the South African public towards economic inequality, general preferences for government-led redistribution, as well as support for social policies intended to promote racial and economic transformation. The research has been guided by several overarching questions: To what extent do South Africans share common general beliefs about material inequality? Does the public exhibit a preference for government redistribution in principle? And how unified or polarised are South Africans in their support for specific redress policies in the country? Responding to these questions has been achieved by drawing on unique, nationally representative data from the South African Social Attitudes Survey (SASAS), which has enabled me to chart social attitudes over a period of almost fifteen years between late 2003 and early 2017. Use has also been made of social citizenship as a guiding conceptual framework to understanding social policy predispositions and analysing attitudinal change. The results demonstrate that the public is united in its awareness of and deep concern about economic inequality. Since the early 2000s, a significant majority has consistently expressed the view that the income gap in the country is too large, articulated a strong preference for a more equitable social structure, and acknowledged the class and social tensions that economic inequality has produced. There is also a preference for a narrowing of earnings disparities, a more generous minimum wage, and regulatory limits on executive pay. While this suggests a desire for fair and legitimate remuneration, the analysis also reveals that South Africans are willing to tolerate fairly high levels of inequality. Nonetheless, these beliefs are generally interpreted as a desire for a more equitable and fair society. This preference for change is reflected in a fairly strong belief that government should assume responsibility for reducing material disparities. One’s social position, mobility history, awareness of inequality, political leaning and racial attitudes all have a bearing on how weak and strong this predisposition is, but the normative demand for political redistribution remains fairly widely shared irrespective of these individual traits. Greater polarisation is however evident with respect to redistributive social policy, especially measures designed to overcome historical racial injustice (affirmative action, sports quotas, and land reform). These intergroup differences converge considerably when referring to class-based policy measures. One surprising finding is the evidence that South Africa’s youngest generation, the so-called ‘Born Frees’, tend to adopt a similar predisposition to redress policy as older generations, thus confounding expectations of a post-apartheid value change. I conclude by arguing that there seems to be a firmer basis for a social compact about preferences for interventions designed to produce a more just society than is typically assumed. Intractably high levels of economic inequality during the country’s first quarter-century of democracy is resulting in a growing recognition of the need for a stronger policy emphasis on economic inequality in South Africa over coming decades if the vision enshrined in the Freedom Charter and the Constitution is to be realised. South Africans may not be able to fully agree about the specific elements that constitute a socially just response to economic inequality. Yet, the common identification of and concern with redressable injustice, coupled with a broad-based commitment to government redistribution and classbased social policies, could serve as a foundation on which to rekindle the solidaristic spirit of 1994 and forge progress towards a more equitable society.
- Full Text:
- Date Issued: 2019
Cheetah Acinonyx jubatus behaviour and resource use in response to other African large carnivores
- Authors: Cornhill, Kristina
- Date: 2019
- Subjects: Cheetahs -- Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44735 , vital:38169
- Description: Competition occurs between species for shared resources. Subordinate species employ resource selection to shift their resource use away from that of dominant species in order to avoid the negative consequences of competition. Only in Africa is the post-Pleistocene large carnivore guild intact, consisting of lions Panthera leo, spotted hyaenas Crocuta crocuta, leopards Panthera pardus, cheetahs Acinonyx jubatus, and African wild dogs Lycaon pictus. Therefore, only in Africa can we explore how large carnivores co-exist with one another in a diverse community. Cheetahs are a subordinate member of the large carnivore guild due to their small stature and solitary nature. However, we still do not fully understand how competition shapes cheetah behaviour and resource use. I used cheetahs as a model subordinate predator to determine the behavioural responses and resource selection of cheetah in response to assumed competition from other large carnivores. I experimentally explored the behavioural response of cheetah to large carnivore scent sources (scats) and their presence at cheetah scent-marking sites to test for avoidance of such cues. Moreover, using unplanned experiments based on the resource use of cheetahs in the absence and then presence of lions (assessing space and time use by cheetah) and African wild dogs (assessing prey use by both species), I evaluated resource selection by cheetahs as a way to reduce competition with these large carnivores. In addition, I measured spatial and temporal partitioning between cheetahs and all four large carnivores at camera trap sites. Finally, I assessed whether cheetahs responded to competitors using a long term proactive response or a short term reactive response. I found that all four of the other large carnivores in the guild shaped cheetahs resource use, however, all did so on different axes in accordance with the niche complementarity hypothesis. Lions and spotted hyenas were avoided through time, African wild dogs through space and prey use, and lions and leopards on the spatiotemporal axis. Moreover, I show that cheetahs utilize a reactive response to competition that allows them to avoid risk while still obtaining necessary resources.
- Full Text:
- Date Issued: 2019
- Authors: Cornhill, Kristina
- Date: 2019
- Subjects: Cheetahs -- Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44735 , vital:38169
- Description: Competition occurs between species for shared resources. Subordinate species employ resource selection to shift their resource use away from that of dominant species in order to avoid the negative consequences of competition. Only in Africa is the post-Pleistocene large carnivore guild intact, consisting of lions Panthera leo, spotted hyaenas Crocuta crocuta, leopards Panthera pardus, cheetahs Acinonyx jubatus, and African wild dogs Lycaon pictus. Therefore, only in Africa can we explore how large carnivores co-exist with one another in a diverse community. Cheetahs are a subordinate member of the large carnivore guild due to their small stature and solitary nature. However, we still do not fully understand how competition shapes cheetah behaviour and resource use. I used cheetahs as a model subordinate predator to determine the behavioural responses and resource selection of cheetah in response to assumed competition from other large carnivores. I experimentally explored the behavioural response of cheetah to large carnivore scent sources (scats) and their presence at cheetah scent-marking sites to test for avoidance of such cues. Moreover, using unplanned experiments based on the resource use of cheetahs in the absence and then presence of lions (assessing space and time use by cheetah) and African wild dogs (assessing prey use by both species), I evaluated resource selection by cheetahs as a way to reduce competition with these large carnivores. In addition, I measured spatial and temporal partitioning between cheetahs and all four large carnivores at camera trap sites. Finally, I assessed whether cheetahs responded to competitors using a long term proactive response or a short term reactive response. I found that all four of the other large carnivores in the guild shaped cheetahs resource use, however, all did so on different axes in accordance with the niche complementarity hypothesis. Lions and spotted hyenas were avoided through time, African wild dogs through space and prey use, and lions and leopards on the spatiotemporal axis. Moreover, I show that cheetahs utilize a reactive response to competition that allows them to avoid risk while still obtaining necessary resources.
- Full Text:
- Date Issued: 2019
Civil society engagement with water governance at a local government scale in South Africa
- Weaver, Matthew James Thanduxolo
- Authors: Weaver, Matthew James Thanduxolo
- Date: 2019
- Subjects: Government accountability -- South Africa , Civil Society -- South Africa , Political participation -- South Africa , Local government -- South Africa , Water supply -- Management , Water resources development -- South Africa , Water quality management -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/151316 , vital:39051
- Description: The South African state’s ideological commitment to a participatory approach to managing water resources and delivering services in a way that includes all stakeholders warrants critical analysis.Realising this ideological commitment has proved challenging, due largely to the complex historical, political, social, and environmental context of integrated water resource management (IWRM) in South Africa. The overarching aim of this study was to explore and expand the learning of civil societyparticipating in water governance processes at a local government scale. To address this aim a single, in-depth, four-year case study into civil society participation in water governance in the Makana Local Municipality in the Eastern Cape Province of South Africa was conducted between 2014 and 2018. The case study comprised two research phases. Both phases of the research were conducted using an adaptive transdisciplinary and participatory action research approach underpinned by General Complexity Theory. Located at the research-practice interface, the study sought to be transformative and advance both scientific research and societal goals. Qualitative research methods and inductive and deductive modes of inference were used to collect and analyse the data respectively. In the first phase of the study, a Communities of Practice theoretical framing was adopted to investigate the emergence, practice and learning of a civil society organisation (CSO), Water for Dignity (WfD), in response to household water service delivery issues in the municipality. This phase served to build an understanding of factors that enabled and constrained the practice of WfD in addressing local water service issues, and of their role as social learning agents in building water-related knowledge in their community. As participation with the first civil society organisation fragmented, the opportunity arose for local government, the National Department of Water and Sanitation and civil society to co-engage. This opened up the second phase of the research during which the role of a multi-stakeholder platform, the Makana Water Forum (MWF), in enabling democratic water governance was investigated. The MWF was South Africa’s first catchment management forum with an integrated water service and water resource management agenda. In this phase, the study drew on interventionist methodology, Change Laboratory, from Cultural Historical Activity Theory (CHAT) to 1) describe the historical development, composition and shared purpose of the MWF multi-activity system constellation; and to 2) guide participants through seven learning actions (expansive learning cycle) to identify, analyse, model and implement remedial actions to problematic aspects (contradictions) of the MWF practice. Participants of the Change Laboratory workshops built their individual and collective transformative agency (deliberate actions to transform a problematic situation) as they navigated the expansive learning process. The development of this agency was identified through a micro-analysis of agentive talk. The two phases served to advance the exploration of civil society participation from informal participation to address water issues, to formal participation in water governance processes at a local government scale. Findings from the first phase of the research revealed that dedicated and sustained support of partners with distributed expertise and the highly motivated core members of WfD enabled the practice and emergence of the civil society organisation. However, factors such as poor internal leadership, power dynamics between supporting partners, socio-economic constraints and a deeply embedded lack of agency were found to be key constraining factors to WfD’s practice. Findings revealed that learning at WfD team level occurred in four ways, through learning as belonging, learning as doing, learning as experiencing and learning as becoming. The WfD CSO was able to catalyse social learning related to personal water rights; and best practices for improving water quality and water conservation in their wider community of practice. Social learning was fostered mainly through structured citizen engagements offered by WfD. The research provides evidence that civil society organisations can play an important role in bridging water-related knowledge gaps and can foster active citizenship in South African communities. However, despite significant inputs of support and resources through the engaged transdisciplinary research process, the practice and learning outcomes of WfD had a marginal transformative impact on improving the citizen’s every-day water service experiences. Findings from the second phase of the study revealed the MWF to resemble a multi-activity system constellation with a multiple, partially overlapping. interests related to the management of water. The establishment, function and contradictions constraining the function of the MWF were influenced by past cycles of participatory water governance-related activity and practice at national and local scales. Through the Change Laboratory process, 25 contradictions were identified that appeared to constrain the ability of the MWF to enable inclusive and meaningful participatory water governance. Through a process of expansive learning, participants sought to overcome three sets of contradictions grouped as Problem Themes: lack of clear focus of the MWF; representation, representivity and nonattendance; and the MWF relationship with the Makana Local Municipality. Remedial actions modelled and those enacted have improved aspects of the function of the MWF (such as diversified modes of engagement and a more focussed agenda) but have only resulted in incremental shifts towards enabling improved participatory practice, most markedly in building a collaborative relationship and trust between the MWF members, municipal and government officials. The microanalysis of agentive talk revealed seven different expressions of transformative agency. Constraining socio-economic and political conditions and the limited capacity of the coordinating committee of the MWF hindered the development of transformative agency to the extent to which concrete actions were implemented. Findings further revealed that contextualising a Change Laboratory process within the adaptive cycle of a complex social-ecological system, and the particular opportunity context the system presents, could inform the enactment of agency and its potential impact on the transformation of the system. The intervention with the MWF was too short a process to clearly observe the effects of transformative actions on the sustainability of the Makana Local Municipality water system. However, long-chain transformative agency through the development of one-on-one engagements, learning journeys and a reflexive component to the MWF engagements could support transformative pathways to sustainability in the municipality and water management system. The study contributes in-depth insight into the key role of learning as a catalyst in transformative processes. Learning improves the collaborative and adaptive capacity of people, and therefore, water management institutions, to manage explicitly for the complexity inherent in “complex” socialecological systems. It provides empirical evidence as to what enables and constrains “real” participation and learning in grass-roots water governance processes in the context of a shifting national drive towards a more adaptive and developmental Integrated Water Resource Management approach. It further provides methodological contributions to 1) the application of the Change Laboratory method with multi-activity system constellations in developing world contexts and 2) value and limitations of extended and engaged transdisciplinary research. Lastly, it provides practical recommendations to the establishment and sustainable function of both community-based CSOs and multi-stakeholder platforms engaging in water governance processes.
- Full Text:
- Date Issued: 2019
- Authors: Weaver, Matthew James Thanduxolo
- Date: 2019
- Subjects: Government accountability -- South Africa , Civil Society -- South Africa , Political participation -- South Africa , Local government -- South Africa , Water supply -- Management , Water resources development -- South Africa , Water quality management -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/151316 , vital:39051
- Description: The South African state’s ideological commitment to a participatory approach to managing water resources and delivering services in a way that includes all stakeholders warrants critical analysis.Realising this ideological commitment has proved challenging, due largely to the complex historical, political, social, and environmental context of integrated water resource management (IWRM) in South Africa. The overarching aim of this study was to explore and expand the learning of civil societyparticipating in water governance processes at a local government scale. To address this aim a single, in-depth, four-year case study into civil society participation in water governance in the Makana Local Municipality in the Eastern Cape Province of South Africa was conducted between 2014 and 2018. The case study comprised two research phases. Both phases of the research were conducted using an adaptive transdisciplinary and participatory action research approach underpinned by General Complexity Theory. Located at the research-practice interface, the study sought to be transformative and advance both scientific research and societal goals. Qualitative research methods and inductive and deductive modes of inference were used to collect and analyse the data respectively. In the first phase of the study, a Communities of Practice theoretical framing was adopted to investigate the emergence, practice and learning of a civil society organisation (CSO), Water for Dignity (WfD), in response to household water service delivery issues in the municipality. This phase served to build an understanding of factors that enabled and constrained the practice of WfD in addressing local water service issues, and of their role as social learning agents in building water-related knowledge in their community. As participation with the first civil society organisation fragmented, the opportunity arose for local government, the National Department of Water and Sanitation and civil society to co-engage. This opened up the second phase of the research during which the role of a multi-stakeholder platform, the Makana Water Forum (MWF), in enabling democratic water governance was investigated. The MWF was South Africa’s first catchment management forum with an integrated water service and water resource management agenda. In this phase, the study drew on interventionist methodology, Change Laboratory, from Cultural Historical Activity Theory (CHAT) to 1) describe the historical development, composition and shared purpose of the MWF multi-activity system constellation; and to 2) guide participants through seven learning actions (expansive learning cycle) to identify, analyse, model and implement remedial actions to problematic aspects (contradictions) of the MWF practice. Participants of the Change Laboratory workshops built their individual and collective transformative agency (deliberate actions to transform a problematic situation) as they navigated the expansive learning process. The development of this agency was identified through a micro-analysis of agentive talk. The two phases served to advance the exploration of civil society participation from informal participation to address water issues, to formal participation in water governance processes at a local government scale. Findings from the first phase of the research revealed that dedicated and sustained support of partners with distributed expertise and the highly motivated core members of WfD enabled the practice and emergence of the civil society organisation. However, factors such as poor internal leadership, power dynamics between supporting partners, socio-economic constraints and a deeply embedded lack of agency were found to be key constraining factors to WfD’s practice. Findings revealed that learning at WfD team level occurred in four ways, through learning as belonging, learning as doing, learning as experiencing and learning as becoming. The WfD CSO was able to catalyse social learning related to personal water rights; and best practices for improving water quality and water conservation in their wider community of practice. Social learning was fostered mainly through structured citizen engagements offered by WfD. The research provides evidence that civil society organisations can play an important role in bridging water-related knowledge gaps and can foster active citizenship in South African communities. However, despite significant inputs of support and resources through the engaged transdisciplinary research process, the practice and learning outcomes of WfD had a marginal transformative impact on improving the citizen’s every-day water service experiences. Findings from the second phase of the study revealed the MWF to resemble a multi-activity system constellation with a multiple, partially overlapping. interests related to the management of water. The establishment, function and contradictions constraining the function of the MWF were influenced by past cycles of participatory water governance-related activity and practice at national and local scales. Through the Change Laboratory process, 25 contradictions were identified that appeared to constrain the ability of the MWF to enable inclusive and meaningful participatory water governance. Through a process of expansive learning, participants sought to overcome three sets of contradictions grouped as Problem Themes: lack of clear focus of the MWF; representation, representivity and nonattendance; and the MWF relationship with the Makana Local Municipality. Remedial actions modelled and those enacted have improved aspects of the function of the MWF (such as diversified modes of engagement and a more focussed agenda) but have only resulted in incremental shifts towards enabling improved participatory practice, most markedly in building a collaborative relationship and trust between the MWF members, municipal and government officials. The microanalysis of agentive talk revealed seven different expressions of transformative agency. Constraining socio-economic and political conditions and the limited capacity of the coordinating committee of the MWF hindered the development of transformative agency to the extent to which concrete actions were implemented. Findings further revealed that contextualising a Change Laboratory process within the adaptive cycle of a complex social-ecological system, and the particular opportunity context the system presents, could inform the enactment of agency and its potential impact on the transformation of the system. The intervention with the MWF was too short a process to clearly observe the effects of transformative actions on the sustainability of the Makana Local Municipality water system. However, long-chain transformative agency through the development of one-on-one engagements, learning journeys and a reflexive component to the MWF engagements could support transformative pathways to sustainability in the municipality and water management system. The study contributes in-depth insight into the key role of learning as a catalyst in transformative processes. Learning improves the collaborative and adaptive capacity of people, and therefore, water management institutions, to manage explicitly for the complexity inherent in “complex” socialecological systems. It provides empirical evidence as to what enables and constrains “real” participation and learning in grass-roots water governance processes in the context of a shifting national drive towards a more adaptive and developmental Integrated Water Resource Management approach. It further provides methodological contributions to 1) the application of the Change Laboratory method with multi-activity system constellations in developing world contexts and 2) value and limitations of extended and engaged transdisciplinary research. Lastly, it provides practical recommendations to the establishment and sustainable function of both community-based CSOs and multi-stakeholder platforms engaging in water governance processes.
- Full Text:
- Date Issued: 2019
Communication barriers within virtual communities in an ethnoreligious diverse society: a case study of Nigeria
- Authors: Ogunnubi ,Adeyemi
- Date: 2019
- Subjects: Communication
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15859 , vital:40533
- Description: The study explores the communication barriers that exist within virtual communities in an ethno-religious diverse society like Nigeria. Qualitative research approach was employed. Subsequently, data was collected using qualitative questionnaire that contained open ended questions and through participant observation (online ethnography). Purposive sampling was used to select participants through liaising with Facebook users, as one of the online virtual communities in Nigeria. Having monitored online discourse on Facebook for some months, this study purposively selected 300 active facebook users from various Nigerian cultural and ethnic backgrounds, but only 60 participants indicated their interest to participate. Also, out of the 60 participants who agreed to participate, only 30 participants (25 males and 5 females) fully participated to the final stage while the other 30 withdrew from the study. The participants were mainly adults between the age brackets of 20 and 59. Thematic Analysis was subsequently used to analyse the data by identifying main themes to provide detailed descriptions of the setting, participants as well as activities. The findings of this study revealed that majority of the participants agree that due to Facebook familiarity and Nigeria's religious colouration, there is a display of disrespect, insolence and deep arrogance to other interactants online. The study further identified and revealed other barriers such as differences in cultural backgrounds and opinions, lack of politeness, prejudging and filtering, name calling and insults. The study proposes that social media platforms as virtual communities should be regulated with full implementation of the law and its sustenance, regardless of individuals having power to make their own choices about the kind of languages they use within virtual communities and considering its effect on other online users. Vulgar languages, hate speeches, incitements, bullying and other offensive comments would hopefully be curbed to the barest minimum if this intervention could be implemented. The conclusion of the study was that Nigerians should be civil in responding to discourse in virtual communities as certain inflammatory, religious or utterances based on ethnicity due to an uninformed perspective usually display one's poor knowledge on issues of national interests
- Full Text:
- Date Issued: 2019
- Authors: Ogunnubi ,Adeyemi
- Date: 2019
- Subjects: Communication
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/15859 , vital:40533
- Description: The study explores the communication barriers that exist within virtual communities in an ethno-religious diverse society like Nigeria. Qualitative research approach was employed. Subsequently, data was collected using qualitative questionnaire that contained open ended questions and through participant observation (online ethnography). Purposive sampling was used to select participants through liaising with Facebook users, as one of the online virtual communities in Nigeria. Having monitored online discourse on Facebook for some months, this study purposively selected 300 active facebook users from various Nigerian cultural and ethnic backgrounds, but only 60 participants indicated their interest to participate. Also, out of the 60 participants who agreed to participate, only 30 participants (25 males and 5 females) fully participated to the final stage while the other 30 withdrew from the study. The participants were mainly adults between the age brackets of 20 and 59. Thematic Analysis was subsequently used to analyse the data by identifying main themes to provide detailed descriptions of the setting, participants as well as activities. The findings of this study revealed that majority of the participants agree that due to Facebook familiarity and Nigeria's religious colouration, there is a display of disrespect, insolence and deep arrogance to other interactants online. The study further identified and revealed other barriers such as differences in cultural backgrounds and opinions, lack of politeness, prejudging and filtering, name calling and insults. The study proposes that social media platforms as virtual communities should be regulated with full implementation of the law and its sustenance, regardless of individuals having power to make their own choices about the kind of languages they use within virtual communities and considering its effect on other online users. Vulgar languages, hate speeches, incitements, bullying and other offensive comments would hopefully be curbed to the barest minimum if this intervention could be implemented. The conclusion of the study was that Nigerians should be civil in responding to discourse in virtual communities as certain inflammatory, religious or utterances based on ethnicity due to an uninformed perspective usually display one's poor knowledge on issues of national interests
- Full Text:
- Date Issued: 2019
Conditions constraining and enabling research production in Historically Black Universities in South Africa
- Authors: Muthama, Evelyn
- Date: 2019
- Subjects: Universities and colleges, Black -- South Africa , Universities and colleges -- Research -- South Africa , Education, Higher -- South Africa , Universities and colleges -- South Africa -- History , Black people -- Education -- South Africa -- History , Discrimination in higher education -- South Africa -- History
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/131527 , vital:36591
- Description: The South African higher education system has a highly uneven landscape emerging from its apartheid past. Institutions remain categorised along racial lines within categories known as ‘Historically Black’ and ‘Historically White’ institutions, or alternatively ‘Historically Disadvantaged’ and ‘Historically Advantaged’ universities. Alongside such categorisations, universities fall within three types, which arose from the restructuring of the higher education landscape post-apartheid through a series of mergers: traditional universities, comprehensive universities, and universities of technology. This study which is part of a larger National Research Foundation-funded project looking at institutional differentiation in South Africa, sought to investigate the conditions enabling and constraining production of research in the Historically Black Universities (HBUs). By providing clarity as to the nature of truth and the concept of knowledge underpinning study, Critical Realism ensures that the study moves beyond the experiences and events captured in the data to the identification of causal mechanisms. Archer’s theory of Social Realism is used alongside Critical Realism, both as a meta-theory to provide an account of the social world and as a more substantive theory in the analysis of data. Social Realism entails understanding that the social world emerges in a complex interplay of powers in the domains of structure, culture and agency. Identifying the powers in each of these domains that enabled or constrained research development meant moving beyond suggesting simple causal relationships to ensure that I identified the complexities of the interplay of mechanisms. Data was collected from all seven institutions designated by the Department of Higher Education and Training as HBUs, by online survey, in depth interviews with academics and heads of research, and through the collection of a range of national and institutional documentation. Using analytical dualism, I endeavoured to identify some of the enablements and constraints at play. There were a number of areas of strength in research in the HBUs. There has also been a significant increase in research output over the last decade; however, the study also identified a number of mechanisms that constrained research productivity. The study found that while there were a number of mechanisms that appeared to have causal tendencies across all the institutions, there were a number of very specific institutional differences. There was very little consistency in understanding of the purpose of research as being key to what universities and academics do. The implication of this incoherence in the domain of culture (i.e. beliefs and discourses in Archer’s terms) is that various interventions in the structural domain intended to foster increased research output often had unintended consequences. Unless there are explicit discussions about how and why research is valuable to the institution and to the country there is unlikely to be sustained growth in output. In particular, the data analysis raises concerns about an instrumentalist understanding of research output in the domain of culture. This in part emerged from the lack of a historical culture of research and was found to be complimentary to managerialist discourses. Another key mechanism identified in the analysis was the use of direct incentives to drive research productivity. Such initiatives seemed to be complementary to a more instrumentalist understanding of the purpose of research and thereby to potentially constrain the likelihood of sustained research growth. While many of the participants were in favour of the use of research incentives, it was also evident that this was often problematic because it steered academics towards salami slicing, and other practices focused on quantity as opposed to quality research. Predatory publications, in particular, have emerged as a problem whereby the research does not get read or cited and so it fails to contribute to knowledge dissemination. Another constraint to research production was related to the increased casualisation of academic staff, which has exacerbated difficulties in attracting and retaining staff especially in rural areas. In South Africa, 56% of academics in universities are now hired on a contract basis which constrained the nurturing of an academic identity and the extent of commitment to the university and its particular academic project. In the HBUs, these employment conditions were exacerbated by increased teaching loads as a result of increased number of students (undergraduates and postgraduates) that have not been matched with similar increases in academic staff. There was a nascent discourse of social justice that focused on research as a core driver of knowledge production in some of the HBUs. This is potentially an area of strength for the HBUs especially emerging from their rural position as there was a complementary culture of social concerns. There was evidence that the nexus between research and community engagement could be a strong means of both strengthening institutional identity and increasing research productivity. But unless the nexus is clearly articulated, a systematic process of support is unlikely to emerge. Given the extent to which the rural positioning of HBUs has been acknowledged to constrain research engagement, this finding has a number of positive implications.
- Full Text:
- Date Issued: 2019
- Authors: Muthama, Evelyn
- Date: 2019
- Subjects: Universities and colleges, Black -- South Africa , Universities and colleges -- Research -- South Africa , Education, Higher -- South Africa , Universities and colleges -- South Africa -- History , Black people -- Education -- South Africa -- History , Discrimination in higher education -- South Africa -- History
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/131527 , vital:36591
- Description: The South African higher education system has a highly uneven landscape emerging from its apartheid past. Institutions remain categorised along racial lines within categories known as ‘Historically Black’ and ‘Historically White’ institutions, or alternatively ‘Historically Disadvantaged’ and ‘Historically Advantaged’ universities. Alongside such categorisations, universities fall within three types, which arose from the restructuring of the higher education landscape post-apartheid through a series of mergers: traditional universities, comprehensive universities, and universities of technology. This study which is part of a larger National Research Foundation-funded project looking at institutional differentiation in South Africa, sought to investigate the conditions enabling and constraining production of research in the Historically Black Universities (HBUs). By providing clarity as to the nature of truth and the concept of knowledge underpinning study, Critical Realism ensures that the study moves beyond the experiences and events captured in the data to the identification of causal mechanisms. Archer’s theory of Social Realism is used alongside Critical Realism, both as a meta-theory to provide an account of the social world and as a more substantive theory in the analysis of data. Social Realism entails understanding that the social world emerges in a complex interplay of powers in the domains of structure, culture and agency. Identifying the powers in each of these domains that enabled or constrained research development meant moving beyond suggesting simple causal relationships to ensure that I identified the complexities of the interplay of mechanisms. Data was collected from all seven institutions designated by the Department of Higher Education and Training as HBUs, by online survey, in depth interviews with academics and heads of research, and through the collection of a range of national and institutional documentation. Using analytical dualism, I endeavoured to identify some of the enablements and constraints at play. There were a number of areas of strength in research in the HBUs. There has also been a significant increase in research output over the last decade; however, the study also identified a number of mechanisms that constrained research productivity. The study found that while there were a number of mechanisms that appeared to have causal tendencies across all the institutions, there were a number of very specific institutional differences. There was very little consistency in understanding of the purpose of research as being key to what universities and academics do. The implication of this incoherence in the domain of culture (i.e. beliefs and discourses in Archer’s terms) is that various interventions in the structural domain intended to foster increased research output often had unintended consequences. Unless there are explicit discussions about how and why research is valuable to the institution and to the country there is unlikely to be sustained growth in output. In particular, the data analysis raises concerns about an instrumentalist understanding of research output in the domain of culture. This in part emerged from the lack of a historical culture of research and was found to be complimentary to managerialist discourses. Another key mechanism identified in the analysis was the use of direct incentives to drive research productivity. Such initiatives seemed to be complementary to a more instrumentalist understanding of the purpose of research and thereby to potentially constrain the likelihood of sustained research growth. While many of the participants were in favour of the use of research incentives, it was also evident that this was often problematic because it steered academics towards salami slicing, and other practices focused on quantity as opposed to quality research. Predatory publications, in particular, have emerged as a problem whereby the research does not get read or cited and so it fails to contribute to knowledge dissemination. Another constraint to research production was related to the increased casualisation of academic staff, which has exacerbated difficulties in attracting and retaining staff especially in rural areas. In South Africa, 56% of academics in universities are now hired on a contract basis which constrained the nurturing of an academic identity and the extent of commitment to the university and its particular academic project. In the HBUs, these employment conditions were exacerbated by increased teaching loads as a result of increased number of students (undergraduates and postgraduates) that have not been matched with similar increases in academic staff. There was a nascent discourse of social justice that focused on research as a core driver of knowledge production in some of the HBUs. This is potentially an area of strength for the HBUs especially emerging from their rural position as there was a complementary culture of social concerns. There was evidence that the nexus between research and community engagement could be a strong means of both strengthening institutional identity and increasing research productivity. But unless the nexus is clearly articulated, a systematic process of support is unlikely to emerge. Given the extent to which the rural positioning of HBUs has been acknowledged to constrain research engagement, this finding has a number of positive implications.
- Full Text:
- Date Issued: 2019
Construction material logistics management: the case of North-Central Nigeria
- Authors: Alumbugu, Polycarp Olaku
- Date: 2019
- Subjects: Construction industry -- Nigeria
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44556 , vital:38132
- Description: The Management of Construction Material Logistics Systems plays a significant role in meeting the goals of cost, quality and time to completion of a construction project. Fundamentally, it is accepted that any inefficiency in the delivery of construction material could lead to a time overrun and thus, a rise in construction costs. Therefore addressing the operational performance of logistics would have a positive impact on the goals of a construction project. The aim of this study was to investigate and evaluate the operational performance of material logistics in North-Central Nigeria as there is little specific research conducted on its effectiveness and efficiency. The methodology used included an extensive literature review and a field study conducted on ten quantitative approach that is rooted in the positivist paradigm, and purposive sampling techniques, was adopted. The descriptive method of data analysis was employed, and the findings and interpretations presented through graphs and images. Analysis of the findings led to the conclusion that material logistics did not operate as a system. There was almost no collaboration and integration of the logistics systems to create a synergistic interrelationship between functions in pursuit of higher overall effectiveness and efficiency. Improvement was needed in warehouse and transport operations and processes; technology and automation of logistics operations were absent, and delivery of material to customers was not effective. The implication was that the current materials logistics system did not meet the delivery goals of cost, quality and time of a construction project. The recommendations suggested included the adoption of the framework developed in this study. This would serve as a guide towards effective and efficient logistics management for material manufacturing firms, and for construction professionals.
- Full Text:
- Date Issued: 2019
- Authors: Alumbugu, Polycarp Olaku
- Date: 2019
- Subjects: Construction industry -- Nigeria
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44556 , vital:38132
- Description: The Management of Construction Material Logistics Systems plays a significant role in meeting the goals of cost, quality and time to completion of a construction project. Fundamentally, it is accepted that any inefficiency in the delivery of construction material could lead to a time overrun and thus, a rise in construction costs. Therefore addressing the operational performance of logistics would have a positive impact on the goals of a construction project. The aim of this study was to investigate and evaluate the operational performance of material logistics in North-Central Nigeria as there is little specific research conducted on its effectiveness and efficiency. The methodology used included an extensive literature review and a field study conducted on ten quantitative approach that is rooted in the positivist paradigm, and purposive sampling techniques, was adopted. The descriptive method of data analysis was employed, and the findings and interpretations presented through graphs and images. Analysis of the findings led to the conclusion that material logistics did not operate as a system. There was almost no collaboration and integration of the logistics systems to create a synergistic interrelationship between functions in pursuit of higher overall effectiveness and efficiency. Improvement was needed in warehouse and transport operations and processes; technology and automation of logistics operations were absent, and delivery of material to customers was not effective. The implication was that the current materials logistics system did not meet the delivery goals of cost, quality and time of a construction project. The recommendations suggested included the adoption of the framework developed in this study. This would serve as a guide towards effective and efficient logistics management for material manufacturing firms, and for construction professionals.
- Full Text:
- Date Issued: 2019
CubiCal: a fast radio interferometric calibration suite exploiting complex optimisation
- Authors: Kenyon, Jonathan
- Date: 2019
- Subjects: Interferometry , Radio astronomy , Python (Computer program language) , Square Kilometre Array (Project)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92341 , vital:30711
- Description: The advent of the Square Kilometre Array and its precursors marks the start of an exciting era for radio interferometry. However, with new instruments producing unprecedented quantities of data, many existing calibration algorithms and implementations will be hard-pressed to keep up. Fortunately, it has recently been shown that the radio interferometric calibration problem can be expressed concisely using the ideas of complex optimisation. The resulting framework exposes properties of the calibration problem which can be exploited to accelerate traditional non-linear least squares algorithms. We extend the existing work on the topic by considering the more general problem of calibrating a Jones chain: the product of several unknown gain terms. We also derive specialised solvers for performing phase-only, delay and pointing error calibration. In doing so, we devise a method for determining update rules for arbitrary, real-valued parametrisations of a complex gain. The solvers are implemented in an optimised Python package called CubiCal. CubiCal makes use of Cython to generate fast C and C++ routines for performing computationally demanding tasks whilst leveraging multiprocessing and shared memory to take advantage of modern, parallel hardware. The package is fully compatible with the measurement set, the most common format for interferometer data, and is well integrated with Montblanc - a third party package which implements optimised model visibility prediction. CubiCal's calibration routines are applied successfully to both simulated and real data for the field surrounding source 3C147. These tests include direction-independent and direction dependent calibration, as well as tests of the specialised solvers. Finally, we conduct extensive performance benchmarks and verify that CubiCal convincingly outperforms its most comparable competitor.
- Full Text:
- Date Issued: 2019
- Authors: Kenyon, Jonathan
- Date: 2019
- Subjects: Interferometry , Radio astronomy , Python (Computer program language) , Square Kilometre Array (Project)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/92341 , vital:30711
- Description: The advent of the Square Kilometre Array and its precursors marks the start of an exciting era for radio interferometry. However, with new instruments producing unprecedented quantities of data, many existing calibration algorithms and implementations will be hard-pressed to keep up. Fortunately, it has recently been shown that the radio interferometric calibration problem can be expressed concisely using the ideas of complex optimisation. The resulting framework exposes properties of the calibration problem which can be exploited to accelerate traditional non-linear least squares algorithms. We extend the existing work on the topic by considering the more general problem of calibrating a Jones chain: the product of several unknown gain terms. We also derive specialised solvers for performing phase-only, delay and pointing error calibration. In doing so, we devise a method for determining update rules for arbitrary, real-valued parametrisations of a complex gain. The solvers are implemented in an optimised Python package called CubiCal. CubiCal makes use of Cython to generate fast C and C++ routines for performing computationally demanding tasks whilst leveraging multiprocessing and shared memory to take advantage of modern, parallel hardware. The package is fully compatible with the measurement set, the most common format for interferometer data, and is well integrated with Montblanc - a third party package which implements optimised model visibility prediction. CubiCal's calibration routines are applied successfully to both simulated and real data for the field surrounding source 3C147. These tests include direction-independent and direction dependent calibration, as well as tests of the specialised solvers. Finally, we conduct extensive performance benchmarks and verify that CubiCal convincingly outperforms its most comparable competitor.
- Full Text:
- Date Issued: 2019
Culturally-informed coping strategies of posttraumatic stress disorders among the black Africans in the greater Accra region of Ghana and black Africans in the eastern cape of South Africa
- Authors: Thompson, Sandra
- Date: 2019
- Subjects: Posttraumatic stress disorder
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44625 , vital:38154
- Description: The influence of culture in coping with Posttraumatic Stress Disorders (PTSD) has been highlighted in literature. However, these culture specific coping strategies are not as yet, extensively explored. The research sought to explore and describe the culturally - informed coping strategies of PTS D among the black Africans in the Greater Accra Region of Ghana and black Africans in the Eastern Cape of South Africa. A qualitative methodological approach was used to explore the phenomenon under study. Purposive non - probability sampling was employed to obtain access to participants who could inform the objectives of the study. Data was collected using semi - structured interviews with traumatised individuals and focus group discussions with cultural leaders. All interviews were audio - recorded, transcribed, translated and analysed using thematic content analysis to facilitate the description and comparison of the similarities and distinctive features emerging from the two African communities. The findings indicated that a number of cultural factors influence interpretation of symptoms of PTSD and the adopted coping strategies. Participants’ understanding of symptoms of PTSD relied heavily on Christian Religious and African cultural understandings. It was evident that almost all explanations were purely spiritual and minimal knowledge was expressed on cognitive interpretations. A great deal of emphasis by the Ghanaians and isiXhosa of South Africa, was on dreams and such interpretations were deferred to an authoritative individual (especially the traditional healer). An obvious hierarchy for coping emerged with the traditional healer playing a major role for the Ghanaian and isiXhosa participants. Performing rites and the use of plants were essential to healing for these group of individuals. Whereas, the Coloured - Afrikaans made reference to a higher power “God”. An outstanding observation was the extent to which Ghanaian and isiXhosa participants have incorporated Christian and traditional practices (i.e. praying to God, performing rites and using herbs or plants). Even where an individual did not wish to mix practice because of upbringing, they acknowledged the existence and effectiveness of these practices. Colonisation was drawn on as an explanation for such mixed practices. The advent of Christianity was explained as having established Western culture (specifically Christianity) that is incorporated by participants. The Coloured - Afrikaans on the other hand, were consistent with the Christian practices “prayers to God”. A great deal of consistency however existed among all participants. Social support was considered very important. Talking with family and friends were relevant to the healing process as it gets rid of distorted thought patterns and avoids isolation considered as a serious current threat to healing. While there was an element of cognitive understanding, Western based treatment using cognitive restructuring was not a treatment option. Clinical practitioners or Psychologists that come into contact with the black Ghanaians and black South Africans should consider collaborative treatment strategies using the draft checklist as a guide.
- Full Text:
- Date Issued: 2019
- Authors: Thompson, Sandra
- Date: 2019
- Subjects: Posttraumatic stress disorder
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44625 , vital:38154
- Description: The influence of culture in coping with Posttraumatic Stress Disorders (PTSD) has been highlighted in literature. However, these culture specific coping strategies are not as yet, extensively explored. The research sought to explore and describe the culturally - informed coping strategies of PTS D among the black Africans in the Greater Accra Region of Ghana and black Africans in the Eastern Cape of South Africa. A qualitative methodological approach was used to explore the phenomenon under study. Purposive non - probability sampling was employed to obtain access to participants who could inform the objectives of the study. Data was collected using semi - structured interviews with traumatised individuals and focus group discussions with cultural leaders. All interviews were audio - recorded, transcribed, translated and analysed using thematic content analysis to facilitate the description and comparison of the similarities and distinctive features emerging from the two African communities. The findings indicated that a number of cultural factors influence interpretation of symptoms of PTSD and the adopted coping strategies. Participants’ understanding of symptoms of PTSD relied heavily on Christian Religious and African cultural understandings. It was evident that almost all explanations were purely spiritual and minimal knowledge was expressed on cognitive interpretations. A great deal of emphasis by the Ghanaians and isiXhosa of South Africa, was on dreams and such interpretations were deferred to an authoritative individual (especially the traditional healer). An obvious hierarchy for coping emerged with the traditional healer playing a major role for the Ghanaian and isiXhosa participants. Performing rites and the use of plants were essential to healing for these group of individuals. Whereas, the Coloured - Afrikaans made reference to a higher power “God”. An outstanding observation was the extent to which Ghanaian and isiXhosa participants have incorporated Christian and traditional practices (i.e. praying to God, performing rites and using herbs or plants). Even where an individual did not wish to mix practice because of upbringing, they acknowledged the existence and effectiveness of these practices. Colonisation was drawn on as an explanation for such mixed practices. The advent of Christianity was explained as having established Western culture (specifically Christianity) that is incorporated by participants. The Coloured - Afrikaans on the other hand, were consistent with the Christian practices “prayers to God”. A great deal of consistency however existed among all participants. Social support was considered very important. Talking with family and friends were relevant to the healing process as it gets rid of distorted thought patterns and avoids isolation considered as a serious current threat to healing. While there was an element of cognitive understanding, Western based treatment using cognitive restructuring was not a treatment option. Clinical practitioners or Psychologists that come into contact with the black Ghanaians and black South Africans should consider collaborative treatment strategies using the draft checklist as a guide.
- Full Text:
- Date Issued: 2019
Data quality issues in electronic health records for large-scale databases
- Authors: Saiod, Abdul Kader
- Date: 2019
- Subjects: Healthcare -- Data quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44577 , vital:38145
- Description: Data Quality (DQ) in Electronic Health Records (EHRs) is one of the core functions that play a decisive role to improve the healthcare service quality. The DQ issues in EHRs are a noticeable trend to improve the introduction of an adaptive framework for interoperability and standards in Large-Scale Databases (LSDB) management systems. Therefore, large data communications are challenging in the traditional approaches to satisfy the needs of the consumers, as data is often not capture directly into the Database Management Systems (DBMS) in a seasonably enough fashion to enable their subsequent uses. In addition, large data plays a vital role in containing plenty of treasures for all the fields in the DBMS. EHRs technology provides portfolio management systems that allow HealthCare Organisations (HCOs) to deliver a higher quality of care to their patients than that which is possible with paper-based records. EHRs are in high demand for HCOs to run their daily services as increasing numbers of huge datasets occur every day. Efficient EHR systems reduce the data redundancy as well as the system application failure and increase the possibility to draw all necessary reports. However, one of the main challenges in developing efficient EHR systems is the inherent difficulty to coherently manage data from diverse heterogeneous sources. It is practically challenging to integrate diverse data into a global schema, which satisfies the need of users. The efficient management of EHR systems using an existing DBMS present challenges because of incompatibility and sometimes inconsistency of data structures. As a result, no common methodological approach is currently in existence to effectively solve every data integration problem. The challenges of the DQ issue raised the need to find an efficient way to integrate large EHRs from diverse heterogeneous sources. To handle and align a large dataset efficiently, the hybrid algorithm method with the logical combination of Fuzzy-Ontology along with a large-scale EHRs analysis platform has shown the results in term of improved accuracy. This study investigated and addressed the raised DQ issues to interventions to overcome these barriers and challenges, including the provision of EHRs as they pertain to DQ and has combined features to search, extract, filter, clean and integrate data to ensure that users can coherently create new consistent data sets. The study researched the design of a hybrid method based on Fuzzy-Ontology with performed mathematical simulations based on the Markov Chain Probability Model. The similarity measurement based on dynamic Hungarian algorithm was followed by the Design Science Research (DSR) methodology, which will increase the quality of service over HCOs in adaptive frameworks.
- Full Text:
- Date Issued: 2019
- Authors: Saiod, Abdul Kader
- Date: 2019
- Subjects: Healthcare -- Data quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/44577 , vital:38145
- Description: Data Quality (DQ) in Electronic Health Records (EHRs) is one of the core functions that play a decisive role to improve the healthcare service quality. The DQ issues in EHRs are a noticeable trend to improve the introduction of an adaptive framework for interoperability and standards in Large-Scale Databases (LSDB) management systems. Therefore, large data communications are challenging in the traditional approaches to satisfy the needs of the consumers, as data is often not capture directly into the Database Management Systems (DBMS) in a seasonably enough fashion to enable their subsequent uses. In addition, large data plays a vital role in containing plenty of treasures for all the fields in the DBMS. EHRs technology provides portfolio management systems that allow HealthCare Organisations (HCOs) to deliver a higher quality of care to their patients than that which is possible with paper-based records. EHRs are in high demand for HCOs to run their daily services as increasing numbers of huge datasets occur every day. Efficient EHR systems reduce the data redundancy as well as the system application failure and increase the possibility to draw all necessary reports. However, one of the main challenges in developing efficient EHR systems is the inherent difficulty to coherently manage data from diverse heterogeneous sources. It is practically challenging to integrate diverse data into a global schema, which satisfies the need of users. The efficient management of EHR systems using an existing DBMS present challenges because of incompatibility and sometimes inconsistency of data structures. As a result, no common methodological approach is currently in existence to effectively solve every data integration problem. The challenges of the DQ issue raised the need to find an efficient way to integrate large EHRs from diverse heterogeneous sources. To handle and align a large dataset efficiently, the hybrid algorithm method with the logical combination of Fuzzy-Ontology along with a large-scale EHRs analysis platform has shown the results in term of improved accuracy. This study investigated and addressed the raised DQ issues to interventions to overcome these barriers and challenges, including the provision of EHRs as they pertain to DQ and has combined features to search, extract, filter, clean and integrate data to ensure that users can coherently create new consistent data sets. The study researched the design of a hybrid method based on Fuzzy-Ontology with performed mathematical simulations based on the Markov Chain Probability Model. The similarity measurement based on dynamic Hungarian algorithm was followed by the Design Science Research (DSR) methodology, which will increase the quality of service over HCOs in adaptive frameworks.
- Full Text:
- Date Issued: 2019
Design and fabrication of components of dye sensitised solar cells
- Authors: Msane, Gugu
- Date: 2019
- Subjects: Dye-sensitized solar cells
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/117106 , vital:34478
- Description: In recent decades there has been increasing global concern about the sustainability of our use of fossil fuels, which has led to increased interest in carbon–free sustainable renewable sources such as solar energy. Dye sensitized solar cells (DSSCs) are a cheap and clean technology that harnesses solar energy efficiently and convert it to electrical energy. A DSSC consists of a transparent working electrode coated with a dye-sensitized mesoporous film of nanocrystalline particles of semiconductor e.g. TiO2, an electrolyte containing a suitable redox couple and a platinized counter electrode. All the components of the DSSCs play vital roles in controlling the performance of the cell. The synergy of these components of the cells also needs to be investigated to optimise their interaction and create efficient and stable DSSCs. The information gathered from this investigation can give insight on how to improve the efficiencies of DSSCs. In this research study the semiconductor, transparent conducting layer and sensitizer were designed, optimized one at a time and their effect on the overall efficiency of the DSSCs studied. In this way it was easy to observe the effect of the individual components on the efficiency of the DSSCs. The conventional DSSCs usually use TiO2 as a semiconductor. In this research TiO2 was doped with cerium (Ce) to enhance its optical properties by reducing the band gap. A series of Ce-doped TiO2 with Ce content ranging from 0.1 to 1 mol % were successfully synthesized by an acid catalyzed sol-gel method, and their performance as the photoanodes of dye-sensitized solar cells (DSSCs) was investigated. Ce doping resulted in a red shift in the absorption of the TiO2 indicating narrowing of the band gap. The band gap first narrowed with increase in concentration of dopant up until 0.9 % dopant concentration. After this optimum doping concentration the band gap widened again. DFT calculations showed that Ce doping introduces Ce4f impurity states located just below the conduction band resulting in band gap narrowing. Ce content (0.9%) doped TiO2 photoanodes improved the performance of DSSCs with a conversion efficiency of 2.11% compared to 0,21% for the one with a pure TiO2 under 1 sun, AM1.5. Graphitised/TiO2 nanocomposites were also used a semiconductor to slow down recombination of electrons and holes in the cells. Electrophoretic deposition (EPD) was used to deposit graphitised/TiO2 nanocomposites onto an FTO electrode for application as photoelectrode in dye-sensitized solar cells (DSSCs). An enhanced power conversion efficiency (PCE) of 2.25% was observed for the 0.5 wt% graphene oxide/TiO2 (GO/TiO2) based DSSC which was higher than that of the conversion efficiency of pure TiO2 nanoparticles (i.e. 0.52%). Graphene oxide led to high migration of photoinduced electrons to the conduction band of the collection electrode and inhibition of charge carriers recombination resulting in enhanced photoconversion efficiency. A GO content above 0.5 % resulted in a reduced transparency leading to a decrease in the PCE. 0.5 wt % GO/0.9 Ce–TiO2 Ce based DSSC showed a slightly enhanced efficiency of 2.45%. 0.5 rGO/TiO2 based DSSCs had a high efficiency than 0.5 rGO/TiO2 due to improved conductivity of rGO nanosheets and suppressed recombination of charge carriers. To cut down DSSC production costs a silver wire network transparent conducting polyethylene electrodes was fabricated and used as an indium tin oxide (ITO) alternative substrates in DSSCs. The transmittance of the AgNW network was 82 % which is comparable to ITO substrates. Titanium oxide (TiO2) films on the AgWN/PET substrates were obtained using the electrophoresis method. These substrates were sensitised and used to fabricate a dye sensitised solar cell. From the measured current–voltage or I-V characteristic under AM1.5 illumination of the formed DSSC using AgWN substrates, an open circuit voltage (VOC) of 0.377 V, a short circuit current (ISC) of 0.0067 mA and a fill factor (FF) 25.7 % with an efficiency of 0.00862 % were obtained from a cell of 0.075 cm2 working area. The stability of the cell improved when a room temperature ionic liquid electrolyte was used. Gold nanofiber transparent electrodes were also prepared by the electrospinning techniques and used as an alternative to indium tin oxides substrates. Transparent conducting gold nanofiber (AuNF) transparent conducting electrodes were fabricated by using a low–cost electrospinning process and used as photoelectrodes for DSSCs. TiO2 was deposited on these electrodes by using an electrospray method. DSSC using AuNF as transparent electrodes had a power efficiency of 0.52%, compared to devices made with FTO electrodes (1.48%). DSSCs. Versatile dyes with increased spectral response, stability and suppressed recombination of holes and electrons were synthesised and used as a sensitizers for DSSCs. The boron dipyrrin (BODIPY) chromophore was combined with a carboxy coumarin moiety to create donor–acceptor (dyad) system dyes. Regenerative dyad dyes were formed through covalently linking a porphyrin chromophore to a manganese(II) ion through bridging ligands. These chromophores and also porphyrin and BODIPY dyes were used as sensitisers for DSSCs. The regenerative dye based DSSCs showed a photoconversion efficiency of 4.09% which was higher than the efficiency of the parent porphyrin (2.57%). The enhanced efficiency was attributed to the manganese bypridine cluster in the ZnTPP–Mn bpy supramolecule which acted as an electron donor to the photo-oxidized porphyrin continuously regenerating the porphyrin and preventing its decay.
- Full Text:
- Date Issued: 2019
- Authors: Msane, Gugu
- Date: 2019
- Subjects: Dye-sensitized solar cells
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/117106 , vital:34478
- Description: In recent decades there has been increasing global concern about the sustainability of our use of fossil fuels, which has led to increased interest in carbon–free sustainable renewable sources such as solar energy. Dye sensitized solar cells (DSSCs) are a cheap and clean technology that harnesses solar energy efficiently and convert it to electrical energy. A DSSC consists of a transparent working electrode coated with a dye-sensitized mesoporous film of nanocrystalline particles of semiconductor e.g. TiO2, an electrolyte containing a suitable redox couple and a platinized counter electrode. All the components of the DSSCs play vital roles in controlling the performance of the cell. The synergy of these components of the cells also needs to be investigated to optimise their interaction and create efficient and stable DSSCs. The information gathered from this investigation can give insight on how to improve the efficiencies of DSSCs. In this research study the semiconductor, transparent conducting layer and sensitizer were designed, optimized one at a time and their effect on the overall efficiency of the DSSCs studied. In this way it was easy to observe the effect of the individual components on the efficiency of the DSSCs. The conventional DSSCs usually use TiO2 as a semiconductor. In this research TiO2 was doped with cerium (Ce) to enhance its optical properties by reducing the band gap. A series of Ce-doped TiO2 with Ce content ranging from 0.1 to 1 mol % were successfully synthesized by an acid catalyzed sol-gel method, and their performance as the photoanodes of dye-sensitized solar cells (DSSCs) was investigated. Ce doping resulted in a red shift in the absorption of the TiO2 indicating narrowing of the band gap. The band gap first narrowed with increase in concentration of dopant up until 0.9 % dopant concentration. After this optimum doping concentration the band gap widened again. DFT calculations showed that Ce doping introduces Ce4f impurity states located just below the conduction band resulting in band gap narrowing. Ce content (0.9%) doped TiO2 photoanodes improved the performance of DSSCs with a conversion efficiency of 2.11% compared to 0,21% for the one with a pure TiO2 under 1 sun, AM1.5. Graphitised/TiO2 nanocomposites were also used a semiconductor to slow down recombination of electrons and holes in the cells. Electrophoretic deposition (EPD) was used to deposit graphitised/TiO2 nanocomposites onto an FTO electrode for application as photoelectrode in dye-sensitized solar cells (DSSCs). An enhanced power conversion efficiency (PCE) of 2.25% was observed for the 0.5 wt% graphene oxide/TiO2 (GO/TiO2) based DSSC which was higher than that of the conversion efficiency of pure TiO2 nanoparticles (i.e. 0.52%). Graphene oxide led to high migration of photoinduced electrons to the conduction band of the collection electrode and inhibition of charge carriers recombination resulting in enhanced photoconversion efficiency. A GO content above 0.5 % resulted in a reduced transparency leading to a decrease in the PCE. 0.5 wt % GO/0.9 Ce–TiO2 Ce based DSSC showed a slightly enhanced efficiency of 2.45%. 0.5 rGO/TiO2 based DSSCs had a high efficiency than 0.5 rGO/TiO2 due to improved conductivity of rGO nanosheets and suppressed recombination of charge carriers. To cut down DSSC production costs a silver wire network transparent conducting polyethylene electrodes was fabricated and used as an indium tin oxide (ITO) alternative substrates in DSSCs. The transmittance of the AgNW network was 82 % which is comparable to ITO substrates. Titanium oxide (TiO2) films on the AgWN/PET substrates were obtained using the electrophoresis method. These substrates were sensitised and used to fabricate a dye sensitised solar cell. From the measured current–voltage or I-V characteristic under AM1.5 illumination of the formed DSSC using AgWN substrates, an open circuit voltage (VOC) of 0.377 V, a short circuit current (ISC) of 0.0067 mA and a fill factor (FF) 25.7 % with an efficiency of 0.00862 % were obtained from a cell of 0.075 cm2 working area. The stability of the cell improved when a room temperature ionic liquid electrolyte was used. Gold nanofiber transparent electrodes were also prepared by the electrospinning techniques and used as an alternative to indium tin oxides substrates. Transparent conducting gold nanofiber (AuNF) transparent conducting electrodes were fabricated by using a low–cost electrospinning process and used as photoelectrodes for DSSCs. TiO2 was deposited on these electrodes by using an electrospray method. DSSC using AuNF as transparent electrodes had a power efficiency of 0.52%, compared to devices made with FTO electrodes (1.48%). DSSCs. Versatile dyes with increased spectral response, stability and suppressed recombination of holes and electrons were synthesised and used as a sensitizers for DSSCs. The boron dipyrrin (BODIPY) chromophore was combined with a carboxy coumarin moiety to create donor–acceptor (dyad) system dyes. Regenerative dyad dyes were formed through covalently linking a porphyrin chromophore to a manganese(II) ion through bridging ligands. These chromophores and also porphyrin and BODIPY dyes were used as sensitisers for DSSCs. The regenerative dye based DSSCs showed a photoconversion efficiency of 4.09% which was higher than the efficiency of the parent porphyrin (2.57%). The enhanced efficiency was attributed to the manganese bypridine cluster in the ZnTPP–Mn bpy supramolecule which acted as an electron donor to the photo-oxidized porphyrin continuously regenerating the porphyrin and preventing its decay.
- Full Text:
- Date Issued: 2019