The development of a commercial production process for p-menthane-3,8-diol
- Authors: Rust, Nico
- Date: 2009
- Subjects: Insect pests -- Control , Repellents
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10427 , http://hdl.handle.net/10948/d1018273
- Description: The synthesis of p-menthane-3,8-diol via the acid-catalyzed cyclization of citronellal in a dilute aqueous sulphuric acid medium was investigated using conventional batch and continuous systems in order to develop a commercial production process for said p-menthane-3,8-diol (PMD). The batch studies conducted during the first part of this study showed that the formation of PMD from citronellal occurs via an intra-molecular Prins reaction that results in the formation of both the desired PMD product, as well as the partially hydrated isopulegol. It was shown that the formationof the by- product, PMD-acetal, results from the reaction between an intermediate, 5-methyl-2- isopropylcyclohexanol, and the citronellal starting material, and not from the reaction between PMD and citronellal as previously reported. Kinetic studies confirmed the existence of a complicated kinetic model. The formation of PMD from citronellal displayed typical pseudo first order kinetics up to conversions of 70 after which the kinetic model becomes complicated as the result of the establishment of quasi equilibrium reactions between PMD and isopulegol (dehydration of PMD and hydration of isopulegol) and between PMD the PMD-acetal, both systems being acid catalysed. The PMD-acetal formation reaction appears to be second order with respect to PMD. Scale-up studies of the batch process to 30L and 50L scales showed that it would be extremely difficult to limit the level of PMD-acetal formation below the desired level of 1 percent, even if citronellal conversions are restricted to about 50 percent. During studies conducted on a commercially availablemicro-structured organic synthesis plant (OSP) it was shown that it is possible to perform the PMD reaction as a continuous process. The results obtained showed that the use of a micro-mixer such as the caterpillar micro-mixer did not provide enough residence time in order for desirable conversions (- 40 percent) to be obtained. By combining themicro-mixer with delay-loops of different thicknesses and lengths, and using increasing reaction temperatures, it was shown that the conversion of citronellal could be improved to some extent, but compared poorly to the expected conversions for a well-stirred batch reactor. By packing selected delay loops with inert SiC particles, improved mass transfer was observed between the organic and aqueous phases as reflected in the increased conversion of citronellal. Using the observations that were made during the use of the OSP, a continuous-flow, tubular reactor system was designed and constructed. Advanced statistical techniques were used to investigate the effect of variables such as temperature, acid concentration, reactor length, flow rate and the organic to aqueous ratio on the rate and selectivity of the reaction. Mathematical models were derived for citronellal conversion, yield of PMD and yield of PMD- acetals, and used to predict the concentrations of citronellal, PMD and PMD-acetals at set experimental conditions. The results obtained showed that it was possible to obtain a product which approached desired specifications.Downstream processing of the PMD reaction mixture as it exits the reactor requires phase separation and neutralization of the acid catalyst solution, followed by further work-up to recover unreacted starting material and intermediates for recycle back to the synthesis reactor, followed by purification of crude PMD to the desired specification. The study showed that neutralization, prior or after phase separation, does not affect the selectivity of the PMD to such a great extent, but does influence the relative conversion due to extended contact of the catalyst with the organic phase after the reaction is terminated. Recovery of unreacted citronellal and isopulegol could be achieved by a simple vacuum evaporation step, which may either be carried out in a batch manner using traditional distillation equipment, or in a continuous process using wiped-film (short path) techniques. It was also shown that selective crystallization of PMD from the crude product mixture by addition of a solvent, such as heptanes or hexane proved to be the best way of achieving the desired product specification.
- Full Text:
- Date Issued: 2009
- Authors: Rust, Nico
- Date: 2009
- Subjects: Insect pests -- Control , Repellents
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10427 , http://hdl.handle.net/10948/d1018273
- Description: The synthesis of p-menthane-3,8-diol via the acid-catalyzed cyclization of citronellal in a dilute aqueous sulphuric acid medium was investigated using conventional batch and continuous systems in order to develop a commercial production process for said p-menthane-3,8-diol (PMD). The batch studies conducted during the first part of this study showed that the formation of PMD from citronellal occurs via an intra-molecular Prins reaction that results in the formation of both the desired PMD product, as well as the partially hydrated isopulegol. It was shown that the formationof the by- product, PMD-acetal, results from the reaction between an intermediate, 5-methyl-2- isopropylcyclohexanol, and the citronellal starting material, and not from the reaction between PMD and citronellal as previously reported. Kinetic studies confirmed the existence of a complicated kinetic model. The formation of PMD from citronellal displayed typical pseudo first order kinetics up to conversions of 70 after which the kinetic model becomes complicated as the result of the establishment of quasi equilibrium reactions between PMD and isopulegol (dehydration of PMD and hydration of isopulegol) and between PMD the PMD-acetal, both systems being acid catalysed. The PMD-acetal formation reaction appears to be second order with respect to PMD. Scale-up studies of the batch process to 30L and 50L scales showed that it would be extremely difficult to limit the level of PMD-acetal formation below the desired level of 1 percent, even if citronellal conversions are restricted to about 50 percent. During studies conducted on a commercially availablemicro-structured organic synthesis plant (OSP) it was shown that it is possible to perform the PMD reaction as a continuous process. The results obtained showed that the use of a micro-mixer such as the caterpillar micro-mixer did not provide enough residence time in order for desirable conversions (- 40 percent) to be obtained. By combining themicro-mixer with delay-loops of different thicknesses and lengths, and using increasing reaction temperatures, it was shown that the conversion of citronellal could be improved to some extent, but compared poorly to the expected conversions for a well-stirred batch reactor. By packing selected delay loops with inert SiC particles, improved mass transfer was observed between the organic and aqueous phases as reflected in the increased conversion of citronellal. Using the observations that were made during the use of the OSP, a continuous-flow, tubular reactor system was designed and constructed. Advanced statistical techniques were used to investigate the effect of variables such as temperature, acid concentration, reactor length, flow rate and the organic to aqueous ratio on the rate and selectivity of the reaction. Mathematical models were derived for citronellal conversion, yield of PMD and yield of PMD- acetals, and used to predict the concentrations of citronellal, PMD and PMD-acetals at set experimental conditions. The results obtained showed that it was possible to obtain a product which approached desired specifications.Downstream processing of the PMD reaction mixture as it exits the reactor requires phase separation and neutralization of the acid catalyst solution, followed by further work-up to recover unreacted starting material and intermediates for recycle back to the synthesis reactor, followed by purification of crude PMD to the desired specification. The study showed that neutralization, prior or after phase separation, does not affect the selectivity of the PMD to such a great extent, but does influence the relative conversion due to extended contact of the catalyst with the organic phase after the reaction is terminated. Recovery of unreacted citronellal and isopulegol could be achieved by a simple vacuum evaporation step, which may either be carried out in a batch manner using traditional distillation equipment, or in a continuous process using wiped-film (short path) techniques. It was also shown that selective crystallization of PMD from the crude product mixture by addition of a solvent, such as heptanes or hexane proved to be the best way of achieving the desired product specification.
- Full Text:
- Date Issued: 2009
On the evaluation of spectral effects on photovoltaic modules performance parameters and hotspots in solar cells
- Authors: Simon, Michael
- Date: 2009
- Subjects: Photovoltaic cells , Energy dissipation , Electric power production , Photovoltaic power generation , Solar energy , Spectral energy distribution
- Language: English
- Type: Thesis , Doctoral , PhD (Physics)
- Identifier: vital:11593 , http://hdl.handle.net/10353/257 , Photovoltaic cells , Energy dissipation , Electric power production , Photovoltaic power generation , Solar energy , Spectral energy distribution
- Description: The performance of photovoltaic (PV) modules in terms of their ability to convert incident photon to electrical energy (efficiency) depends mostly on the spectral distribution of incident radiation from the sun. The incident spectrum finally perceived by the module depends strongly on the composition of the medium in which it has traveled. The composition of the earth’s atmosphere, which includes, amongst others, water vapour, gases such as carbon dioxide and oxygen, absorbs or scatters some of the sunlight. The incident solar spectrum is also modified by the diffuse aspect of radiation from the sky which strongly depends on aerosol concentration, cloudiness and local reflection of the earth’s surface. Although it is well known that the changes in outdoor spectrum affect device performance, little work has been conducted to support this theory. This is probably due to lack of spectral data or in certain instances where data is available, little knowledge of interpreting that data. The outdoor spectral data that one obtains in the field does not come clearly for just simple interpretation. Different analytical interpretation procedures have been proposed, all trying to explain and quantify the spectral influence on PV devices. In this study an assessment methodology for evaluating the effects of outdoor spectra on device performance parameters during the course of the day, seasons and or cloudy cover has been developed. The methodology consists of developing a device dependant concept, Weighted Useful Fraction (WUF) using the outdoor measured spectral data. For measuring PV module’s performance parameters, a current-voltage (I-V) tester was developed in order to monitor the performance of six different module technologies. The Gaussian distribution was used to interpret the data. For hot-spot analysis, different techniques were used, which include Infrared thermographic technique for identifying the hot-spots in the solar cells, SEM and EDX techniques. The AES technique was also used in order to identify other elements at hot-spots sites that could not be detected by the EDX technique. iii Results obtained indicate that multicrystalline modules performance is affected by the changes in the outdoor spectrum during summer or winter seasons. The modules prefer a spectrum characterized by WUF = 0.809 during summer season. This spectrum corresponds to AM 2.19 which is different from AM 1.5 used for device ratings. In winter, the mc-Si module’s WUF (0.7125) peaks at 13h00 at a value corresponding to AM 1.83. Although these devices have a wider wavelength range, they respond differently in real outdoor environment. Results for mono – Si module showed that the device performs best at WUF = 0.6457 which corresponds to AM 1.83 during summer season, while it operates optimally under a winter spectrum indicated by WUF of 0.5691 (AM2.58). The seasonal changes resulted in the shift in WUF during day time corresponding to the “preferred” spectrum. This shift indicates that these devices should be rated using AM values that correspond to the WUF values under which the device operates optimally. For poly-Si, it was also observed the WUF values are lower than the other two crystalline-Si counterparts. The pc-Si was observed to prefer a lower AM value indicated by WUF = 0.5813 during winter season while for summer it prefers a spectrum characterized by WUF = 0.5541 at AM 3.36. The performance of the single junction a-Si module degraded by 67 percent after an initial outdoor exposure of 16 kWh/m² while the HIT module did not exhibit the initial degradation regardless of their similarities in material composition. It was established that the WUF before degradation peaks at 15h00 at a value of 0.7130 corresponding to AM 4.50 while the WUF after degradation “prefers” the spectrum (WUF = 0.6578) experienced at 15h30 corresponding to AM value of 5.57. Comparing the before and after degradation scenarios of a-Si:H, it was observed that the device spends less time under the red spectrum which implies that the device “prefers” a full spectrum to operate optimally. The degradation of a-Si:H device revealed that the device spectral response was also shifted by a 7.7 percent after degradation. A higher percentage difference (61.8 percent) for spectral range for the HIT module is observed, but with no effects on device parameters. Seasonal changes (summer/winter) resulted in the outdoor spectrum of CuInSe2 to vary by WUF = 1.5 percent, which resulted in the decrease in Isc. This was ascertained by iv analyzing the percentage change in WUF and evaluating the corresponding change in Isc. The analysis showed that there was a large percentage difference of the module’s Isc as the outdoor spectrum changed during the course of the day. This confirmed that the 17 percent decrease in Isc was due to a WUF of 1.5 percent. In mc-Si solar cells used in this study, it was found that elemental composition across the entire solar cell was not homogenously distributed resulting in high concentration of transition metals which were detected at hot spot areas. The presence of transition metals causes hot-spot formation in crystalline solar cells. Although several transition elements exist at hot-spot regions, the presence of oxygen, carbon, iron and platinum was detected in high concentrations. From this study, it is highly recommended that transition elements and oxygen must be minimized so as to increase the life expectancy of these devices and improve overall systems reliability
- Full Text:
- Date Issued: 2009
- Authors: Simon, Michael
- Date: 2009
- Subjects: Photovoltaic cells , Energy dissipation , Electric power production , Photovoltaic power generation , Solar energy , Spectral energy distribution
- Language: English
- Type: Thesis , Doctoral , PhD (Physics)
- Identifier: vital:11593 , http://hdl.handle.net/10353/257 , Photovoltaic cells , Energy dissipation , Electric power production , Photovoltaic power generation , Solar energy , Spectral energy distribution
- Description: The performance of photovoltaic (PV) modules in terms of their ability to convert incident photon to electrical energy (efficiency) depends mostly on the spectral distribution of incident radiation from the sun. The incident spectrum finally perceived by the module depends strongly on the composition of the medium in which it has traveled. The composition of the earth’s atmosphere, which includes, amongst others, water vapour, gases such as carbon dioxide and oxygen, absorbs or scatters some of the sunlight. The incident solar spectrum is also modified by the diffuse aspect of radiation from the sky which strongly depends on aerosol concentration, cloudiness and local reflection of the earth’s surface. Although it is well known that the changes in outdoor spectrum affect device performance, little work has been conducted to support this theory. This is probably due to lack of spectral data or in certain instances where data is available, little knowledge of interpreting that data. The outdoor spectral data that one obtains in the field does not come clearly for just simple interpretation. Different analytical interpretation procedures have been proposed, all trying to explain and quantify the spectral influence on PV devices. In this study an assessment methodology for evaluating the effects of outdoor spectra on device performance parameters during the course of the day, seasons and or cloudy cover has been developed. The methodology consists of developing a device dependant concept, Weighted Useful Fraction (WUF) using the outdoor measured spectral data. For measuring PV module’s performance parameters, a current-voltage (I-V) tester was developed in order to monitor the performance of six different module technologies. The Gaussian distribution was used to interpret the data. For hot-spot analysis, different techniques were used, which include Infrared thermographic technique for identifying the hot-spots in the solar cells, SEM and EDX techniques. The AES technique was also used in order to identify other elements at hot-spots sites that could not be detected by the EDX technique. iii Results obtained indicate that multicrystalline modules performance is affected by the changes in the outdoor spectrum during summer or winter seasons. The modules prefer a spectrum characterized by WUF = 0.809 during summer season. This spectrum corresponds to AM 2.19 which is different from AM 1.5 used for device ratings. In winter, the mc-Si module’s WUF (0.7125) peaks at 13h00 at a value corresponding to AM 1.83. Although these devices have a wider wavelength range, they respond differently in real outdoor environment. Results for mono – Si module showed that the device performs best at WUF = 0.6457 which corresponds to AM 1.83 during summer season, while it operates optimally under a winter spectrum indicated by WUF of 0.5691 (AM2.58). The seasonal changes resulted in the shift in WUF during day time corresponding to the “preferred” spectrum. This shift indicates that these devices should be rated using AM values that correspond to the WUF values under which the device operates optimally. For poly-Si, it was also observed the WUF values are lower than the other two crystalline-Si counterparts. The pc-Si was observed to prefer a lower AM value indicated by WUF = 0.5813 during winter season while for summer it prefers a spectrum characterized by WUF = 0.5541 at AM 3.36. The performance of the single junction a-Si module degraded by 67 percent after an initial outdoor exposure of 16 kWh/m² while the HIT module did not exhibit the initial degradation regardless of their similarities in material composition. It was established that the WUF before degradation peaks at 15h00 at a value of 0.7130 corresponding to AM 4.50 while the WUF after degradation “prefers” the spectrum (WUF = 0.6578) experienced at 15h30 corresponding to AM value of 5.57. Comparing the before and after degradation scenarios of a-Si:H, it was observed that the device spends less time under the red spectrum which implies that the device “prefers” a full spectrum to operate optimally. The degradation of a-Si:H device revealed that the device spectral response was also shifted by a 7.7 percent after degradation. A higher percentage difference (61.8 percent) for spectral range for the HIT module is observed, but with no effects on device parameters. Seasonal changes (summer/winter) resulted in the outdoor spectrum of CuInSe2 to vary by WUF = 1.5 percent, which resulted in the decrease in Isc. This was ascertained by iv analyzing the percentage change in WUF and evaluating the corresponding change in Isc. The analysis showed that there was a large percentage difference of the module’s Isc as the outdoor spectrum changed during the course of the day. This confirmed that the 17 percent decrease in Isc was due to a WUF of 1.5 percent. In mc-Si solar cells used in this study, it was found that elemental composition across the entire solar cell was not homogenously distributed resulting in high concentration of transition metals which were detected at hot spot areas. The presence of transition metals causes hot-spot formation in crystalline solar cells. Although several transition elements exist at hot-spot regions, the presence of oxygen, carbon, iron and platinum was detected in high concentrations. From this study, it is highly recommended that transition elements and oxygen must be minimized so as to increase the life expectancy of these devices and improve overall systems reliability
- Full Text:
- Date Issued: 2009
A knowledge-oriented, context-sensitive architectural framework for service deployment in marginalized rural communities
- Authors: Thinyane, Mamello P
- Date: 2009
- Subjects: Information technology Expert systems (Computer science) Software architecture User interfaces (Computer systems) Ethnoscience Social networks Rural development Technical assistance -- Developing countries Information networks -- Developing countries
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4599 , http://hdl.handle.net/10962/d1004843
- Description: The notion of a global knowledge society is somewhat of a misnomer due to the fact that large portions of the global community are not participants in this global knowledge society which is driven, shaped by and socio-technically biased towards a small fraction of the global population. Information and Communication Technology (ICT) is culture-sensitive and this is a dynamic that is largely ignored in the majority of ICT for Development (ICT4D) interventions, leading to the technological determinism flaw and ultimately a failure of the undertaken projects. The deployment of ICT solutions, in particular in the context of ICT4D, must be informed by the cultural and socio-technical profile of the deployment environments and solutions themselves must be developed with a focus towards context-sensitivity and ethnocentricity. In this thesis, we investigate the viability of a software architectural framework for the development of ICT solutions that are context-sensitive and ethnocentric1, and so aligned with the cultural and social dynamics within the environment of deployment. The conceptual framework, named PIASK, defines five tiers (presentation, interaction, access, social networking, and knowledge base) which allow for: behavioural completeness of the layer components; a modular and functionally decoupled architecture; and the flexibility to situate and contextualize the developed applications along the dimensions of the User Interface (UI), interaction modalities, usage metaphors, underlying Indigenous Knowledge (IK), and access protocols. We have developed a proof-of-concept service platform, called KnowNet, based on the PIASK architecture. KnowNet is built around the knowledge base layer, which consists of domain ontologies that encapsulate the knowledge in the platform, with an intrinsic flexibility to access secondary knowledge repositories. The domain ontologies constructed (as examples) are for the provisioning of eServices to support societal activities (e.g. commerce, health, agriculture, medicine) within a rural and marginalized area of Dwesa, in the Eastern Cape province of South Africa. The social networking layer allows for situating the platform within the local social systems. Heterogeneity of user profiles and multiplicity of end-user devices are handled through the access and the presentation components, and the service logic is implemented by the interaction components. This services platform validates the PIASK architecture for end-to-end provisioning of multi-modal, heterogeneous, ontology-based services. The development of KnowNet was informed on one hand by the latest trends within service architectures, semantic web technologies and social applications, and on the other hand by the context consideration based on the profile (IK systems dynamics, infrastructure, usability requirements) of the Dwesa community. The realization of the service platform is based on the JADE Multi-Agent System (MAS), and this shows the applicability and adequacy of MAS’s for service deployment in a rural context, at the same time providing key advantages such as platform fault-tolerance, robustness and flexibility. While the context of conceptualization of PIASK and the implementation of KnowNet is that of rurality and of ICT4D, the applicability of the architecture extends to other similarly heterogeneous and context-sensitive domains. KnowNet has been validated for functional and technical adequacy, and we have also undertaken an initial prevalidation for social context sensitivity. We observe that the five tier PIASK architecture provides an adequate framework for developing context-sensitive and ethnocentric software: by functionally separating and making explicit the social networking and access tier components, while still maintaining the traditional separation of presentation, business logic and data components.
- Full Text:
- Date Issued: 2009
- Authors: Thinyane, Mamello P
- Date: 2009
- Subjects: Information technology Expert systems (Computer science) Software architecture User interfaces (Computer systems) Ethnoscience Social networks Rural development Technical assistance -- Developing countries Information networks -- Developing countries
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4599 , http://hdl.handle.net/10962/d1004843
- Description: The notion of a global knowledge society is somewhat of a misnomer due to the fact that large portions of the global community are not participants in this global knowledge society which is driven, shaped by and socio-technically biased towards a small fraction of the global population. Information and Communication Technology (ICT) is culture-sensitive and this is a dynamic that is largely ignored in the majority of ICT for Development (ICT4D) interventions, leading to the technological determinism flaw and ultimately a failure of the undertaken projects. The deployment of ICT solutions, in particular in the context of ICT4D, must be informed by the cultural and socio-technical profile of the deployment environments and solutions themselves must be developed with a focus towards context-sensitivity and ethnocentricity. In this thesis, we investigate the viability of a software architectural framework for the development of ICT solutions that are context-sensitive and ethnocentric1, and so aligned with the cultural and social dynamics within the environment of deployment. The conceptual framework, named PIASK, defines five tiers (presentation, interaction, access, social networking, and knowledge base) which allow for: behavioural completeness of the layer components; a modular and functionally decoupled architecture; and the flexibility to situate and contextualize the developed applications along the dimensions of the User Interface (UI), interaction modalities, usage metaphors, underlying Indigenous Knowledge (IK), and access protocols. We have developed a proof-of-concept service platform, called KnowNet, based on the PIASK architecture. KnowNet is built around the knowledge base layer, which consists of domain ontologies that encapsulate the knowledge in the platform, with an intrinsic flexibility to access secondary knowledge repositories. The domain ontologies constructed (as examples) are for the provisioning of eServices to support societal activities (e.g. commerce, health, agriculture, medicine) within a rural and marginalized area of Dwesa, in the Eastern Cape province of South Africa. The social networking layer allows for situating the platform within the local social systems. Heterogeneity of user profiles and multiplicity of end-user devices are handled through the access and the presentation components, and the service logic is implemented by the interaction components. This services platform validates the PIASK architecture for end-to-end provisioning of multi-modal, heterogeneous, ontology-based services. The development of KnowNet was informed on one hand by the latest trends within service architectures, semantic web technologies and social applications, and on the other hand by the context consideration based on the profile (IK systems dynamics, infrastructure, usability requirements) of the Dwesa community. The realization of the service platform is based on the JADE Multi-Agent System (MAS), and this shows the applicability and adequacy of MAS’s for service deployment in a rural context, at the same time providing key advantages such as platform fault-tolerance, robustness and flexibility. While the context of conceptualization of PIASK and the implementation of KnowNet is that of rurality and of ICT4D, the applicability of the architecture extends to other similarly heterogeneous and context-sensitive domains. KnowNet has been validated for functional and technical adequacy, and we have also undertaken an initial prevalidation for social context sensitivity. We observe that the five tier PIASK architecture provides an adequate framework for developing context-sensitive and ethnocentric software: by functionally separating and making explicit the social networking and access tier components, while still maintaining the traditional separation of presentation, business logic and data components.
- Full Text:
- Date Issued: 2009
Racism and law : implementing the right to equality in selected South African equality courts
- Authors: Krüger, Rósaan
- Date: 2009
- Subjects: South Africa Promotion of Equality and Prevention of Unfair Discrimination Act, 2000 , Equality -- South Africa , Discrimination -- Law and legislation -- South Africa , Racism -- Law and legislation -- South Africa , Apartheid -- Law and legislation -- South Africa , Constitutional law -- South Africa , South Africa -- Politics and government -- 1994-
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3677 , http://hdl.handle.net/10962/d1003192 , South Africa Promotion of Equality and Prevention of Unfair Discrimination Act, 2000 , Equality -- South Africa , Discrimination -- Law and legislation -- South Africa , Racism -- Law and legislation -- South Africa , Apartheid -- Law and legislation -- South Africa , Constitutional law -- South Africa , South Africa -- Politics and government -- 1994-
- Description: Racism has informed South African society since colonial times. Racist beliefs found expression in the laws of colonial and apartheid South Africa and shaped both state and society. The constitutional state that South Africa has become since 1994, is based on the values of ‘human dignity’, ‘the achievement of equality’ and ‘nonracialism’, among others. Law formed the basis of the racist state prior to 1994, and now law has a fundamental role to play in the transformation of the state and society in an egalitarian direction by addressing socio-economic inequalities on the one hand, and by changing patterns of behaviour based on racist beliefs forged in the past, on the other. This thesis examines one of the legal instruments that is intended to contribute to transformation in the latter sense, namely the Promotion of Equality and Prevention of Unfair Discrimination Act 4 of 2000 (the Equality Act), with specific reference to the issue of racism. The provisions of this Act and the framework for its operation against the background of South Africa’s racist past, and within the broader framework of international and constitutional law, are examined. These two legal frameworks are analysed for the purpose of determining the standards set by international and constitutional law regarding racial equality in order to determine whether the Equality Act measures up. This thesis also incorporates an analysis of the practical application of the provisions of the Equality Act to complaints of racism in selected equality courts. The theoretical analysis of the Act’s provisions and their application in the equality courts point to various problematic formulations and obstacles which negatively affect the application of the provisions and thus hamper social change. The thesis concludes with recommendations for refining the Act’s provisions and its application.
- Full Text:
- Date Issued: 2009
- Authors: Krüger, Rósaan
- Date: 2009
- Subjects: South Africa Promotion of Equality and Prevention of Unfair Discrimination Act, 2000 , Equality -- South Africa , Discrimination -- Law and legislation -- South Africa , Racism -- Law and legislation -- South Africa , Apartheid -- Law and legislation -- South Africa , Constitutional law -- South Africa , South Africa -- Politics and government -- 1994-
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3677 , http://hdl.handle.net/10962/d1003192 , South Africa Promotion of Equality and Prevention of Unfair Discrimination Act, 2000 , Equality -- South Africa , Discrimination -- Law and legislation -- South Africa , Racism -- Law and legislation -- South Africa , Apartheid -- Law and legislation -- South Africa , Constitutional law -- South Africa , South Africa -- Politics and government -- 1994-
- Description: Racism has informed South African society since colonial times. Racist beliefs found expression in the laws of colonial and apartheid South Africa and shaped both state and society. The constitutional state that South Africa has become since 1994, is based on the values of ‘human dignity’, ‘the achievement of equality’ and ‘nonracialism’, among others. Law formed the basis of the racist state prior to 1994, and now law has a fundamental role to play in the transformation of the state and society in an egalitarian direction by addressing socio-economic inequalities on the one hand, and by changing patterns of behaviour based on racist beliefs forged in the past, on the other. This thesis examines one of the legal instruments that is intended to contribute to transformation in the latter sense, namely the Promotion of Equality and Prevention of Unfair Discrimination Act 4 of 2000 (the Equality Act), with specific reference to the issue of racism. The provisions of this Act and the framework for its operation against the background of South Africa’s racist past, and within the broader framework of international and constitutional law, are examined. These two legal frameworks are analysed for the purpose of determining the standards set by international and constitutional law regarding racial equality in order to determine whether the Equality Act measures up. This thesis also incorporates an analysis of the practical application of the provisions of the Equality Act to complaints of racism in selected equality courts. The theoretical analysis of the Act’s provisions and their application in the equality courts point to various problematic formulations and obstacles which negatively affect the application of the provisions and thus hamper social change. The thesis concludes with recommendations for refining the Act’s provisions and its application.
- Full Text:
- Date Issued: 2009
Effects of marine reserves on the biology of rocky intertidal limpets along the southern coast of South Africa
- Nakin, Motebang Dominic Vincent
- Authors: Nakin, Motebang Dominic Vincent
- Date: 2009
- Subjects: Limpets Marine parks and reserves -- South Africa Marine biology -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5680 , http://hdl.handle.net/10962/d1005365
- Description: Limpets are harvested by people in South Africa, but are selected in terms of species and size. The effects of marine reserves on the biology of commonly exploited (Helcion concolor and Scutellastra longicosta) and rarely exploited species (Cellana capensis and Scutellastra granularis) were investigated on the southeast coast of South Africa at two reserve and two non-reserve sites. For each species, a 4-way nested ANOVA was used to test the effects of month, reserve, site (nested within reserve) and area (nested within site and reserve) on population density, size structure and recruitment of these limpets. The data were collected monthly over 20 months. The overall results indicated a gradient of exploitation among species, S. longicosta was the most heavily exploited species and S. granularis the least exploited species. However, there was also a gradient of exploitation between reserves and non-reserves. Xhora was the most heavily exploited site while Nqabara was less heavily exploited. Of the two reserve sites, Cwebe had more poachers than Dwesa. In most analyses, the month x area (reserve (site)) interaction was significant. However, this was largely an artifact due to comparisons of areas in different sites and significant differences between areas within sites occurred in relatively few months. Densities were greater inside reserves for all species except C. capensis. For S. longicosta and H. concolor this was expected but not for S. granularis and the result possibly reflects its opportunistic exploitation in the absence of the preferred species or indirect effects of reserves. Commonly exploited species and the rarely exploited C. capensis clearly showed greater mean and maximum sizes in reserves but there were month/site (reserve) interactions. Months with significant differences between reserves and nonreserves in both mean and maximum sizes generally occurred more often for commonly exploited than rarely exploited species, but C. capensis showed the strongest reserve effect on maximum size. Interview surveys showed that, although not normally exploited, C. capensis is sometimes mistaken for H. concolor and this suggests that large individuals are unintentionally harvested outside reserves. There were no significant reserve effects on recruitment for any species. Although Xhora had the lowest densities and limpet sizes, it showed the highest recruitment especially for S. longicosta, suggesting that larvae can be transported far from where they are released and settle in non-reserve sites regardless of adult densities. Reserve as a main factor was not significant for the rarely exploited species, but there was a significant month x reserve interaction, with non-reserves having greater GSI values than reserves in most months. Growth rates were examined using individual tagging and cohort analysis. The two techniques gave different results, with individual tagging giving higher growth estimates than cohort analysis. Except for the territorial species S. longicosta, growth was higher in non-reserves and inversely correlated with population density. Mortality estimates using the Cormack-Jolly-Seber model indicated that the rarely exploited species had significantly greater capture probabilities in reserves while no significant reserve effects were observed for the commonly exploited species. Reserve effects on survival probability were significant only for S. longicosta, with reserves being greater than nonreserves and no significant effects for any other species. Enhanced survival in reserves was attributed to the effects of human exploitation. In theory, marine protected areas show increases in densities, sizes and reproductive output of exploited species, but the present results revealed that the efficacy of reserves depends on the status of the species, not only whether it is exploited or non-exploited, but also whether it is territorial.
- Full Text:
- Date Issued: 2009
- Authors: Nakin, Motebang Dominic Vincent
- Date: 2009
- Subjects: Limpets Marine parks and reserves -- South Africa Marine biology -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5680 , http://hdl.handle.net/10962/d1005365
- Description: Limpets are harvested by people in South Africa, but are selected in terms of species and size. The effects of marine reserves on the biology of commonly exploited (Helcion concolor and Scutellastra longicosta) and rarely exploited species (Cellana capensis and Scutellastra granularis) were investigated on the southeast coast of South Africa at two reserve and two non-reserve sites. For each species, a 4-way nested ANOVA was used to test the effects of month, reserve, site (nested within reserve) and area (nested within site and reserve) on population density, size structure and recruitment of these limpets. The data were collected monthly over 20 months. The overall results indicated a gradient of exploitation among species, S. longicosta was the most heavily exploited species and S. granularis the least exploited species. However, there was also a gradient of exploitation between reserves and non-reserves. Xhora was the most heavily exploited site while Nqabara was less heavily exploited. Of the two reserve sites, Cwebe had more poachers than Dwesa. In most analyses, the month x area (reserve (site)) interaction was significant. However, this was largely an artifact due to comparisons of areas in different sites and significant differences between areas within sites occurred in relatively few months. Densities were greater inside reserves for all species except C. capensis. For S. longicosta and H. concolor this was expected but not for S. granularis and the result possibly reflects its opportunistic exploitation in the absence of the preferred species or indirect effects of reserves. Commonly exploited species and the rarely exploited C. capensis clearly showed greater mean and maximum sizes in reserves but there were month/site (reserve) interactions. Months with significant differences between reserves and nonreserves in both mean and maximum sizes generally occurred more often for commonly exploited than rarely exploited species, but C. capensis showed the strongest reserve effect on maximum size. Interview surveys showed that, although not normally exploited, C. capensis is sometimes mistaken for H. concolor and this suggests that large individuals are unintentionally harvested outside reserves. There were no significant reserve effects on recruitment for any species. Although Xhora had the lowest densities and limpet sizes, it showed the highest recruitment especially for S. longicosta, suggesting that larvae can be transported far from where they are released and settle in non-reserve sites regardless of adult densities. Reserve as a main factor was not significant for the rarely exploited species, but there was a significant month x reserve interaction, with non-reserves having greater GSI values than reserves in most months. Growth rates were examined using individual tagging and cohort analysis. The two techniques gave different results, with individual tagging giving higher growth estimates than cohort analysis. Except for the territorial species S. longicosta, growth was higher in non-reserves and inversely correlated with population density. Mortality estimates using the Cormack-Jolly-Seber model indicated that the rarely exploited species had significantly greater capture probabilities in reserves while no significant reserve effects were observed for the commonly exploited species. Reserve effects on survival probability were significant only for S. longicosta, with reserves being greater than nonreserves and no significant effects for any other species. Enhanced survival in reserves was attributed to the effects of human exploitation. In theory, marine protected areas show increases in densities, sizes and reproductive output of exploited species, but the present results revealed that the efficacy of reserves depends on the status of the species, not only whether it is exploited or non-exploited, but also whether it is territorial.
- Full Text:
- Date Issued: 2009
Livestock, rural livelihoods and rural development interventions in the Eastern Cape: case studies of Chris Hani, Alfred Nzo and Amathole district municipalities
- Authors: Phiri, Christopher
- Date: 2009
- Subjects: Rural development -- South Africa -- Eastern Cape Province , Livestock -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , D Soc Sc (Rural Development)
- Identifier: vital:11937 , http://hdl.handle.net/10353/184 , Rural development -- South Africa -- Eastern Cape Province , Livestock -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape
- Description: This study explores how livestock in rural communities were accessed, used as livelihoods portfolios and how off-farm activities and portfolios such as social grants, support from family members and employment assisted the rural poor to build their asset base. Empirical data was collected from 26 villages in the three districts. In particular the study examines firstly, the nature of rural poverty in these villages in the three districts and how households with and without livestock (cattle, sheep, goats, dogs, pigs, cats, ducks, horses and donkeys) used livestock local knowledge to sustain a living. Secondly it explores how the local government and related rural development agencies, intervened in livestock production and the thesis highlights the problematic nature of these interventions, and the implications this has for the form and nature of livestock ownership and use in relation to rural livelihoods. Arising from this, the thesis thirdly explores Ruliv‟s through concrete case studies, the challenges, constraints and implications of a pre-dominant top-down approach to rural development. Contrary to this approach, the study illustrates, through the Rhoxeni case study, the potential effectiveness of a „bottom-up‟ actor oriented approach to rural development. Fourthly, the study explores how local government initiatives intervened in the development of a rural livestock project in Alfred Nzo District Municipality through the Integrated Sustainable Rural Development Programme Goat Project. Here iv the concerns of „commercialisation‟ of livestock production are explored and the thesis points to the implications that the exclusion of social and cultural meanings of livestock have for assumed paths of commercialisation and its associations with development. Fifthly the study explores the potentiality of emerging black commercial farmers who had acquired large areas of agricultural land through local government interventions (Land Redistribution Agricultural Development) but who lacked further support and capacity to transform themselves into commercial farmers. The thesis concludes that their livestock and crop farming activities remained more subsistence and livelihood based, than any transition to expected technical market oriented commercial farming. Overall, the thesis argues that while local government planning for rural development prioritised commercial agriculture as the basis of rural development and the key mechanism of rural poverty alleviation in developmental policies (PGDP, IDP, LED), rural poverty has actually been deepening. In this context, the study argues that the value of livestock to the rural poor lies „outside‟ of its assumed economic value and is more firmly and determinedly located in its social meanings and values, despite these significant levels of material poverty. This has major implications for understanding livelihoods, engaging livestock agency, defining farming and what it means to be a „farmer‟ and engaging with prevalent understandings and practices directed at rural development.
- Full Text:
- Date Issued: 2009
- Authors: Phiri, Christopher
- Date: 2009
- Subjects: Rural development -- South Africa -- Eastern Cape Province , Livestock -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , D Soc Sc (Rural Development)
- Identifier: vital:11937 , http://hdl.handle.net/10353/184 , Rural development -- South Africa -- Eastern Cape Province , Livestock -- South Africa -- Eastern Cape , Rural poor -- South Africa -- Eastern Cape
- Description: This study explores how livestock in rural communities were accessed, used as livelihoods portfolios and how off-farm activities and portfolios such as social grants, support from family members and employment assisted the rural poor to build their asset base. Empirical data was collected from 26 villages in the three districts. In particular the study examines firstly, the nature of rural poverty in these villages in the three districts and how households with and without livestock (cattle, sheep, goats, dogs, pigs, cats, ducks, horses and donkeys) used livestock local knowledge to sustain a living. Secondly it explores how the local government and related rural development agencies, intervened in livestock production and the thesis highlights the problematic nature of these interventions, and the implications this has for the form and nature of livestock ownership and use in relation to rural livelihoods. Arising from this, the thesis thirdly explores Ruliv‟s through concrete case studies, the challenges, constraints and implications of a pre-dominant top-down approach to rural development. Contrary to this approach, the study illustrates, through the Rhoxeni case study, the potential effectiveness of a „bottom-up‟ actor oriented approach to rural development. Fourthly, the study explores how local government initiatives intervened in the development of a rural livestock project in Alfred Nzo District Municipality through the Integrated Sustainable Rural Development Programme Goat Project. Here iv the concerns of „commercialisation‟ of livestock production are explored and the thesis points to the implications that the exclusion of social and cultural meanings of livestock have for assumed paths of commercialisation and its associations with development. Fifthly the study explores the potentiality of emerging black commercial farmers who had acquired large areas of agricultural land through local government interventions (Land Redistribution Agricultural Development) but who lacked further support and capacity to transform themselves into commercial farmers. The thesis concludes that their livestock and crop farming activities remained more subsistence and livelihood based, than any transition to expected technical market oriented commercial farming. Overall, the thesis argues that while local government planning for rural development prioritised commercial agriculture as the basis of rural development and the key mechanism of rural poverty alleviation in developmental policies (PGDP, IDP, LED), rural poverty has actually been deepening. In this context, the study argues that the value of livestock to the rural poor lies „outside‟ of its assumed economic value and is more firmly and determinedly located in its social meanings and values, despite these significant levels of material poverty. This has major implications for understanding livelihoods, engaging livestock agency, defining farming and what it means to be a „farmer‟ and engaging with prevalent understandings and practices directed at rural development.
- Full Text:
- Date Issued: 2009
Insect pests of cultivated and wild olives, and some of their natural enemies, in the Eastern Cape, South Africa
- Authors: Mkize, Nolwazi
- Date: 2009
- Subjects: Pests -- Control -- South Africa -- Eastern Cape Olive -- Diseases and pests -- South Africa -- Eastern Cape Agriculture -- South Africa -- Eastern Cape Fruit-flies -- South Africa -- Eastern Cape Tephritidae Flea beetles Lace bugs
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5717 , http://hdl.handle.net/10962/d1005403
- Description: This thesis has two focuses. The first problem facing the olive industry in the Eastern Cape is the growers’ perceptions of both what the industry will provide them and what a pest management program might entail. The second focus is the biology of olive pests in the Eastern Cape in terms of understanding their populations and their natural enemies on private farms, with future hopes of understanding how Integrated Pest Management strategies can be developed for this crop. Eastern Cape private farmers, small-scale farmers and workers from agricultural training institutions were interviewed regarding the history and cultivation of the local olive crop. Only one commercially viable olive grove was identified; other groves were small, experimental pilot ventures. The introduction of olives to small-scale farmers and agricultural training schools was generally a top-down initiative that led to a lack of sense of ownership and the trees being neglected. Other problems included poor human capital; poor financial capital; lack of adequate support; lack of knowledge transfer and stability; lack of communication and evaluation procedures of the project; miscommunication; and finally, olive pests. Apart from hesitancy to plant at a commercial scale, the main problem facing private farmers (Varnam Farm, Hewlands Farm and Springvale Farm) was pests. Therefore an investigation of pests from private farms was conducted ranging from collection of cultivated and wild olive fruit and flea beetle larvae for parasitism, trapping systems both for fruit flies and olive flea beetle adults. A survey of olive fruits yielded larval fruit flies of the families Tephritidae (Bactrocera oleae (Rossi), B. biguttula (Bezzi) and Ceratitis capitata (Wiedemann)) and Drosophilidae (Drosophila melanogaster (Meigen)) from wild olives (O. europaea cuspidata (Wall. ex G. Don) Cif.) but none from cultivated olives (O. e. europaea L.). Braconid wasps (Opiinae and Braconinae) were reared only from fruits containing B. oleae and B. biguttula. This suggests that B. oleae is not of economic significance in the Eastern Cape, perhaps because it is controlled to a significant level by natural enemies, but B. biguttula may be a potential economic pest. A survey of adult fruit flies using ChamP traps baited with ammonium bicarbonate and spiroketal capsules and Sensus trap baited with methyl eugenol and Questlure confirmed the relative importance of B. biguttula over B. oleae. ChamP traps were over 50 times better than Sensus traps for mass trapping of B. biguttula but both were ineffective for trapping B. oleae and C. capitata. Six indigenous flea beetles of the genus Argopistes Motschulsky (Chrysomelidae: Alticinae) were found, three described by Bryant in 1922 and 1944 and three new species. Their morphology was investigated by scanning electron microscopy and mutivariate morphometric analysis. The leaf-mining larvae are pests of wild and cultivated olives in South Africa and threaten the local olive industry. At Springvale Farm, A. oleae Bryant and A. sexvittatus Bryant preferred the upper parts of trees, near new leaves. Pseudophanomeris inopinatus (Blkb.) (Braconidae) was reared from 23 Argopistes larvae. The beetle larvae might not be controlled to a significant level by natural enemies because the rate of parasitism was low. The olive flea beetles showed no attraction to traps containing various volatile compounds as baits. The lace bug, Plerochila australis Distant (Tingidae), was sometimes a pest. It showed a preference for the underside of leaves on the lower parts of the trees. A moth, Palpita unionalis Hübner (Crambidae), was reared in very low numbers and without parasitoids. A twig-boring beetle larva, chalcidoid parasitoids and seed wasps of the families Eurytomidae, Ormyridae and Eupelmidae were also recorded.
- Full Text:
- Date Issued: 2009
- Authors: Mkize, Nolwazi
- Date: 2009
- Subjects: Pests -- Control -- South Africa -- Eastern Cape Olive -- Diseases and pests -- South Africa -- Eastern Cape Agriculture -- South Africa -- Eastern Cape Fruit-flies -- South Africa -- Eastern Cape Tephritidae Flea beetles Lace bugs
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5717 , http://hdl.handle.net/10962/d1005403
- Description: This thesis has two focuses. The first problem facing the olive industry in the Eastern Cape is the growers’ perceptions of both what the industry will provide them and what a pest management program might entail. The second focus is the biology of olive pests in the Eastern Cape in terms of understanding their populations and their natural enemies on private farms, with future hopes of understanding how Integrated Pest Management strategies can be developed for this crop. Eastern Cape private farmers, small-scale farmers and workers from agricultural training institutions were interviewed regarding the history and cultivation of the local olive crop. Only one commercially viable olive grove was identified; other groves were small, experimental pilot ventures. The introduction of olives to small-scale farmers and agricultural training schools was generally a top-down initiative that led to a lack of sense of ownership and the trees being neglected. Other problems included poor human capital; poor financial capital; lack of adequate support; lack of knowledge transfer and stability; lack of communication and evaluation procedures of the project; miscommunication; and finally, olive pests. Apart from hesitancy to plant at a commercial scale, the main problem facing private farmers (Varnam Farm, Hewlands Farm and Springvale Farm) was pests. Therefore an investigation of pests from private farms was conducted ranging from collection of cultivated and wild olive fruit and flea beetle larvae for parasitism, trapping systems both for fruit flies and olive flea beetle adults. A survey of olive fruits yielded larval fruit flies of the families Tephritidae (Bactrocera oleae (Rossi), B. biguttula (Bezzi) and Ceratitis capitata (Wiedemann)) and Drosophilidae (Drosophila melanogaster (Meigen)) from wild olives (O. europaea cuspidata (Wall. ex G. Don) Cif.) but none from cultivated olives (O. e. europaea L.). Braconid wasps (Opiinae and Braconinae) were reared only from fruits containing B. oleae and B. biguttula. This suggests that B. oleae is not of economic significance in the Eastern Cape, perhaps because it is controlled to a significant level by natural enemies, but B. biguttula may be a potential economic pest. A survey of adult fruit flies using ChamP traps baited with ammonium bicarbonate and spiroketal capsules and Sensus trap baited with methyl eugenol and Questlure confirmed the relative importance of B. biguttula over B. oleae. ChamP traps were over 50 times better than Sensus traps for mass trapping of B. biguttula but both were ineffective for trapping B. oleae and C. capitata. Six indigenous flea beetles of the genus Argopistes Motschulsky (Chrysomelidae: Alticinae) were found, three described by Bryant in 1922 and 1944 and three new species. Their morphology was investigated by scanning electron microscopy and mutivariate morphometric analysis. The leaf-mining larvae are pests of wild and cultivated olives in South Africa and threaten the local olive industry. At Springvale Farm, A. oleae Bryant and A. sexvittatus Bryant preferred the upper parts of trees, near new leaves. Pseudophanomeris inopinatus (Blkb.) (Braconidae) was reared from 23 Argopistes larvae. The beetle larvae might not be controlled to a significant level by natural enemies because the rate of parasitism was low. The olive flea beetles showed no attraction to traps containing various volatile compounds as baits. The lace bug, Plerochila australis Distant (Tingidae), was sometimes a pest. It showed a preference for the underside of leaves on the lower parts of the trees. A moth, Palpita unionalis Hübner (Crambidae), was reared in very low numbers and without parasitoids. A twig-boring beetle larva, chalcidoid parasitoids and seed wasps of the families Eurytomidae, Ormyridae and Eupelmidae were also recorded.
- Full Text:
- Date Issued: 2009
A systems approach to mainstreaming environment and sustainability in universities : the case of Rhodes University, South Africa
- Authors: Togo, Muchaiteyi
- Date: 2009
- Subjects: Rhodes University Education, Higher -- South Africa Universities and colleges -- South Africa Universities and colleges -- Environmental aspects -- South Africa -- Case studies Environmental education -- South Africa -- Case studies Sustainable development -- South Africa -- Case studies
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4768 , http://hdl.handle.net/10962/d1007175
- Description: This study is influenced by the objectives of the Mainstreaming Environment and Sustainability in African Universities Partnership which aims to enhance the quality and relevance of university education through implementation of Environmental Education and sustainability across university functions and operations. It contributes to Education for Sustainable Development through the development of tools to assess sustainability in higher education, investigating sustainability practices in universities and proposing strategies for improving mainstreaming of sustainability. It also contributes to systems approaches in mainstreaming contextual sustainability challenges in university functions and operations. The aim of the study was to investigate how universities can mainstream sustainability in their functions and operations in response to contextual sustainability challenges in a changing environment using a systems approach. The research was a case study of Rhodes University in South Africa, which is situated in the impoverished Eastern Cape Province. The study involved 12 teaching departments (representing all faculties at the university), four research units and institutes, five managements units, the Estates Division and the Student Representative Council. The theoretical framework of the study draws from a critical realist ontology and systems thinking epistemology. Systems thinking emphasises the interdependencies of phenomena, thus providing the methodology and tools for a systems view of relationships between education and the environmental context in which it is embedded. Critical realism was employed as an underlabourer to systems thinking as it provides for some of the dimensions absent in systems thinking including its depth ontology which facilitates isolating causal factors influencing empirical reality. It recognises that explanation of phenomena can be embedded in history and acknowledges the fallibility of knowledge. The data collection methods employed in the study include a sustainability assessment using a Unit-based Sustainability Assessment Tool developed as part of the study, interviews, content analyses and observations. Data analyses were performed through employing morphogenetic analysis, and inductive, abductive and retroductive modes of inference. The morphogenetic analysis of social transformation/reproduction was employed to trace the historical emergence of sustainability initiatives at Rhodes University. Induction facilitated reorganisation of the data into themes which particularly represent the main sustainability activities at Rhodes University. Abduction, through recontextualising data in a systems thinking framework, enabled further insights into the phenomena. In the study, it enabled use of systems lenses as a framework and led to identification of systemic issues affecting mainstreaming and later, the development of systems thinking approaches in mainstreaming sustainability. Retroduction enabled identification of causal mechanisms which influenced the emergence of sustainability initiatives at the university. The study established that the emergence of sustainability initiatives at Rhodes University followed the 1990 Talloires Declaration and paralleled international institutional developments in relation to environmental and sustainability challenges. Since then, sustainability initiatives have continuously been emerging in various operational dimensions of the university in line with emerging sustainability challenges which resulted in a morphogenetic cycle. The study revealed that Rhodes University has mainstreamed sustainability across the functions and operations of most of the departments/divisions/units forming part of the study, especially in functions like teaching, research, community engagement and operations. There were a few exceptions like the Human Resources Division and to an extent the Research Office/Management Division which are not yet considering sustainability in their operations. While most of the teaching departments had sustainability initiatives in teaching, research and community engagement, there was diversity in the dimension(s) of sustainable development that the departments addressed and this seemed to relate to the disciplinary content of their subjects. In the Estates Division sustainability initiatives included sustainable landscaping, campus environmental management, water and energy conservation initiatives, waste recycling, use of biodiesel, to mention a few. Students were also involved in various sustainability activities especially through voluntary community engagement initiatives. Sustainability initiatives at the university were also discovered to be embedded within and responding to sustainability challenges of the immediate university environment of Makana District. The study unearthed the causal mechanisms enabling and constraining mainstreaming activities at the university. These were found to be embedded in the history and context within which the university is operating, and other factors related to university structures and agency of lecturers, other employees and students. Examples of these factors are unsustainable patterns in society, policies and the need to redress past inequalities. The study noted the existence of systemic issues at the university which need to be addressed to enable and enhance the promotion of a systems approach to mainstreaming: notably, complexity owing to diversity of approaches employed in mainstreaming, the absence of clearly defined university sustainability goals, problems of institutional support and in some cases, disciplinary governing rules which do not leave room for mainstreaming sustainability. The study established the possibility of improving mainstreaming of sustainability through the adoption of more explicit systems approaches. It suggests use of systems models including the systems-environment model, the functions/structure model and the motion picture model in the process. It recommends making the goal of mainstreaming more upfront, developing a shared understanding of sustainability and mapping out/defining contextual sustainable development issues to grapple with. The study also recommends adopting a holistic approach in mainstreaming, making it a campus-wide initiative, involving all students and developing interdisciplinary curricula. It suggests setting up of supporting mechanisms to strengthen, extend and spearhead mainstreaming and enhancement of collaborative work in sustainable development issues.
- Full Text:
- Date Issued: 2009
- Authors: Togo, Muchaiteyi
- Date: 2009
- Subjects: Rhodes University Education, Higher -- South Africa Universities and colleges -- South Africa Universities and colleges -- Environmental aspects -- South Africa -- Case studies Environmental education -- South Africa -- Case studies Sustainable development -- South Africa -- Case studies
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4768 , http://hdl.handle.net/10962/d1007175
- Description: This study is influenced by the objectives of the Mainstreaming Environment and Sustainability in African Universities Partnership which aims to enhance the quality and relevance of university education through implementation of Environmental Education and sustainability across university functions and operations. It contributes to Education for Sustainable Development through the development of tools to assess sustainability in higher education, investigating sustainability practices in universities and proposing strategies for improving mainstreaming of sustainability. It also contributes to systems approaches in mainstreaming contextual sustainability challenges in university functions and operations. The aim of the study was to investigate how universities can mainstream sustainability in their functions and operations in response to contextual sustainability challenges in a changing environment using a systems approach. The research was a case study of Rhodes University in South Africa, which is situated in the impoverished Eastern Cape Province. The study involved 12 teaching departments (representing all faculties at the university), four research units and institutes, five managements units, the Estates Division and the Student Representative Council. The theoretical framework of the study draws from a critical realist ontology and systems thinking epistemology. Systems thinking emphasises the interdependencies of phenomena, thus providing the methodology and tools for a systems view of relationships between education and the environmental context in which it is embedded. Critical realism was employed as an underlabourer to systems thinking as it provides for some of the dimensions absent in systems thinking including its depth ontology which facilitates isolating causal factors influencing empirical reality. It recognises that explanation of phenomena can be embedded in history and acknowledges the fallibility of knowledge. The data collection methods employed in the study include a sustainability assessment using a Unit-based Sustainability Assessment Tool developed as part of the study, interviews, content analyses and observations. Data analyses were performed through employing morphogenetic analysis, and inductive, abductive and retroductive modes of inference. The morphogenetic analysis of social transformation/reproduction was employed to trace the historical emergence of sustainability initiatives at Rhodes University. Induction facilitated reorganisation of the data into themes which particularly represent the main sustainability activities at Rhodes University. Abduction, through recontextualising data in a systems thinking framework, enabled further insights into the phenomena. In the study, it enabled use of systems lenses as a framework and led to identification of systemic issues affecting mainstreaming and later, the development of systems thinking approaches in mainstreaming sustainability. Retroduction enabled identification of causal mechanisms which influenced the emergence of sustainability initiatives at the university. The study established that the emergence of sustainability initiatives at Rhodes University followed the 1990 Talloires Declaration and paralleled international institutional developments in relation to environmental and sustainability challenges. Since then, sustainability initiatives have continuously been emerging in various operational dimensions of the university in line with emerging sustainability challenges which resulted in a morphogenetic cycle. The study revealed that Rhodes University has mainstreamed sustainability across the functions and operations of most of the departments/divisions/units forming part of the study, especially in functions like teaching, research, community engagement and operations. There were a few exceptions like the Human Resources Division and to an extent the Research Office/Management Division which are not yet considering sustainability in their operations. While most of the teaching departments had sustainability initiatives in teaching, research and community engagement, there was diversity in the dimension(s) of sustainable development that the departments addressed and this seemed to relate to the disciplinary content of their subjects. In the Estates Division sustainability initiatives included sustainable landscaping, campus environmental management, water and energy conservation initiatives, waste recycling, use of biodiesel, to mention a few. Students were also involved in various sustainability activities especially through voluntary community engagement initiatives. Sustainability initiatives at the university were also discovered to be embedded within and responding to sustainability challenges of the immediate university environment of Makana District. The study unearthed the causal mechanisms enabling and constraining mainstreaming activities at the university. These were found to be embedded in the history and context within which the university is operating, and other factors related to university structures and agency of lecturers, other employees and students. Examples of these factors are unsustainable patterns in society, policies and the need to redress past inequalities. The study noted the existence of systemic issues at the university which need to be addressed to enable and enhance the promotion of a systems approach to mainstreaming: notably, complexity owing to diversity of approaches employed in mainstreaming, the absence of clearly defined university sustainability goals, problems of institutional support and in some cases, disciplinary governing rules which do not leave room for mainstreaming sustainability. The study established the possibility of improving mainstreaming of sustainability through the adoption of more explicit systems approaches. It suggests use of systems models including the systems-environment model, the functions/structure model and the motion picture model in the process. It recommends making the goal of mainstreaming more upfront, developing a shared understanding of sustainability and mapping out/defining contextual sustainable development issues to grapple with. The study also recommends adopting a holistic approach in mainstreaming, making it a campus-wide initiative, involving all students and developing interdisciplinary curricula. It suggests setting up of supporting mechanisms to strengthen, extend and spearhead mainstreaming and enhancement of collaborative work in sustainable development issues.
- Full Text:
- Date Issued: 2009
Characterisation of Trypanosomal Type III and Type IV Hsp40 proteins
- Louw, Cassandra Alexandrovna
- Authors: Louw, Cassandra Alexandrovna
- Date: 2009
- Subjects: Trypanosoma Heat shock proteins African trypanosomiasis Epidemic encephalitis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3926 , http://hdl.handle.net/10962/d1003985
- Description: The heat shock protein-70 (Hsp70) family of molecular chaperones are ubiquitous highly conserved proteins that are critical for the viability of cellular homeostasis. The ATPase activity of Hsp70 proteins is critical to their function as the affinity of a given Hsp70 for non-native substrate is modulated by ATP binding and hydrolysis. When bound to ATP, Hsp70s possess a low affinity for a given substrate protein, while the hydrolysis of ATP to ADP causes a conformational change that results in a high affinity for substrate proteins. The basal ATPase activity of Hsp70s is too low to facilitate their function in vivo, and co-chaperones are essential to modulate the efficient protein folding by Hsp70. Heat shock protein-40 (Hsp40) heat shock proteins are essential for the in vivo function of Hsp70s by stimulating the ATPase activity of these proteins and facilitating transfer of substrates. The Type III class of Hsp40 proteins have not been well characterised due to their poor levels of conservation at the primary sequence level. This is due to the fact that Type III Hsp40s only contain a J-domain and a poorly conserved C-terminal region. The newly identified Type IV class of Hsp40s, contain an abrogated HPD tripeptide motif in the J-domain and have also not been extensively studied. Trypanosoma brucei (T. brucei) is a unicellular flagellated protozoan parasite. It is the causative agent of Human African Trypansomiasis (HAT) which results in thousands of deaths and devastating agricultural losses in many parts of Africa. T. brucei undergoes a complex lifecycle that is characterised by the transition from an insect vector to a mammalian host in markedly different conditions of temperature, pH, nutrient availability and respiratory requirements. It has been proposed that molecular chaperones may enhance the survival of these parasites due to their cytoprotective effect in combating cellular stress. Due to the fact that T. brucei infection is invariably fatal if left untreated, and that no novel treatment regimens have been developed recently, the identification of potential novel drug targets among proteins essential to the parasite’s survival in the host organism is an attractive aspect of T. brucei research. Because Type III Hsp40s are poorly conserved with respect to Hsp40s found in the human host, the identification of any of these proteins found to be essential to T. brucei survival in humans could potentially make attractive novel drug targets. An in depth in silico investigation into the Type III Hsp40 complement as well as partner Hsp70 proteins in T.brucei was performed. T. brucei possesses 65 Hsp40 proteins, of which 47 were classed as Type III and 6 of which were identified as being putative Type IV Hsp40s. A small but significant number (5) of Type III TbHsp40s contained tetratricopeptide (TPR) domains in addition to the J-domain. The J-domains of the Type III TbHsp40 complement were found to be conserved with respect to those of canonical Hsp40 proteins, although the mutation of certain residues that play a key role in Hsp40-Hsp70 interaction was noted. Potential partnerships of these proteins in the parasite was also investigated. The coding regions of three previously uncharacterised TbHsp40s were successfully amplified from T. brucei TREU927 genomic DNA and cloned into an expression vector. Tbj1, a Tcj1 ortholog, was selected for further study and successfully expressed and biochemically characterised. Tbj1 expressed in E. coli was found to be insoluble, but large amounts were recovered with the aid of a denaturing purification followed by refolding elution strategies, and the bulk of the protein recovered was in compact monomeric form as determined by size-exclusion chromatography fast protein liquid chromatography (SEC-FPLC). The addition of Tbj1 to a thermally aggregated substrate resulted in increased levels of aggregation, although Tbj1 was able to assist two Hsp70 proteins in the suppression of aggregation. Tbj1 proved unable to stimulate the ATPase activity of these same Hsp70s, and could not rescue temperature sensitive cells when replacing E.coli DnaJ and CbpA. It was concluded that Tbj1 does not possess independent chaperone activity, but could display Hsp40 co-chaperone properties under certain circumstances. This could allude to a specialised function in the T. brucei parasite. The lack of human orthologues to Tbj1 could result in the attractiveness of this protein as a novel drug target.
- Full Text:
- Date Issued: 2009
- Authors: Louw, Cassandra Alexandrovna
- Date: 2009
- Subjects: Trypanosoma Heat shock proteins African trypanosomiasis Epidemic encephalitis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3926 , http://hdl.handle.net/10962/d1003985
- Description: The heat shock protein-70 (Hsp70) family of molecular chaperones are ubiquitous highly conserved proteins that are critical for the viability of cellular homeostasis. The ATPase activity of Hsp70 proteins is critical to their function as the affinity of a given Hsp70 for non-native substrate is modulated by ATP binding and hydrolysis. When bound to ATP, Hsp70s possess a low affinity for a given substrate protein, while the hydrolysis of ATP to ADP causes a conformational change that results in a high affinity for substrate proteins. The basal ATPase activity of Hsp70s is too low to facilitate their function in vivo, and co-chaperones are essential to modulate the efficient protein folding by Hsp70. Heat shock protein-40 (Hsp40) heat shock proteins are essential for the in vivo function of Hsp70s by stimulating the ATPase activity of these proteins and facilitating transfer of substrates. The Type III class of Hsp40 proteins have not been well characterised due to their poor levels of conservation at the primary sequence level. This is due to the fact that Type III Hsp40s only contain a J-domain and a poorly conserved C-terminal region. The newly identified Type IV class of Hsp40s, contain an abrogated HPD tripeptide motif in the J-domain and have also not been extensively studied. Trypanosoma brucei (T. brucei) is a unicellular flagellated protozoan parasite. It is the causative agent of Human African Trypansomiasis (HAT) which results in thousands of deaths and devastating agricultural losses in many parts of Africa. T. brucei undergoes a complex lifecycle that is characterised by the transition from an insect vector to a mammalian host in markedly different conditions of temperature, pH, nutrient availability and respiratory requirements. It has been proposed that molecular chaperones may enhance the survival of these parasites due to their cytoprotective effect in combating cellular stress. Due to the fact that T. brucei infection is invariably fatal if left untreated, and that no novel treatment regimens have been developed recently, the identification of potential novel drug targets among proteins essential to the parasite’s survival in the host organism is an attractive aspect of T. brucei research. Because Type III Hsp40s are poorly conserved with respect to Hsp40s found in the human host, the identification of any of these proteins found to be essential to T. brucei survival in humans could potentially make attractive novel drug targets. An in depth in silico investigation into the Type III Hsp40 complement as well as partner Hsp70 proteins in T.brucei was performed. T. brucei possesses 65 Hsp40 proteins, of which 47 were classed as Type III and 6 of which were identified as being putative Type IV Hsp40s. A small but significant number (5) of Type III TbHsp40s contained tetratricopeptide (TPR) domains in addition to the J-domain. The J-domains of the Type III TbHsp40 complement were found to be conserved with respect to those of canonical Hsp40 proteins, although the mutation of certain residues that play a key role in Hsp40-Hsp70 interaction was noted. Potential partnerships of these proteins in the parasite was also investigated. The coding regions of three previously uncharacterised TbHsp40s were successfully amplified from T. brucei TREU927 genomic DNA and cloned into an expression vector. Tbj1, a Tcj1 ortholog, was selected for further study and successfully expressed and biochemically characterised. Tbj1 expressed in E. coli was found to be insoluble, but large amounts were recovered with the aid of a denaturing purification followed by refolding elution strategies, and the bulk of the protein recovered was in compact monomeric form as determined by size-exclusion chromatography fast protein liquid chromatography (SEC-FPLC). The addition of Tbj1 to a thermally aggregated substrate resulted in increased levels of aggregation, although Tbj1 was able to assist two Hsp70 proteins in the suppression of aggregation. Tbj1 proved unable to stimulate the ATPase activity of these same Hsp70s, and could not rescue temperature sensitive cells when replacing E.coli DnaJ and CbpA. It was concluded that Tbj1 does not possess independent chaperone activity, but could display Hsp40 co-chaperone properties under certain circumstances. This could allude to a specialised function in the T. brucei parasite. The lack of human orthologues to Tbj1 could result in the attractiveness of this protein as a novel drug target.
- Full Text:
- Date Issued: 2009
Citizen participation, decentralization and inclusive development : a survey on citizen participation and decentralization in South Africa with specific reference to the Eastern Cape c.2005
- Authors: Robino, Carolina
- Date: 2009
- Subjects: Local government -- Citizen participation , Decentralization in government -- South Africa , Political planning -- Citizen participation , Community development, Urban -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9084 , http://hdl.handle.net/10948/875 , Local government -- Citizen participation , Decentralization in government -- South Africa , Political planning -- Citizen participation , Community development, Urban -- South Africa -- Eastern Cape
- Description: Contemporary debates about development confer a prominent role to citizen participation and decentralization. Growing scepticism about the efficacy of narrowly conceived measures add pressure to reform development both theoretically and in practical terms. There is a greater understanding that ‘traditional’ development approaches and policies need to be reformulated and decentralization and citizen participation have been proposed as remedies to previous development failures. It is frequently argued that citizen participation will improve the efficiency and efficacy of public services. Citizen participation is meant to render local government more accountable and to contribute to deepening democracy, by reinforcing representative democratic institutions with participatory forms. At the same time, decentralization reforms have been proposed as a response to the failures of highly centralized states. From a political perspective, it is argued, decentralization reforms can help the central state gain legitimacy and have been seen as a strategy for maintaining political stability. It has been repeatedly suggested that physical proximity makes it easier for citizens to hold local officials accountable for their performance. From an economic perspective, decentralization can improve the match between the mix of services provided by the public sector and the preferences of the local population. It has also been noted that people are more willing to pay for services that respond to their priorities and that increased competition between local governments generates spaces for more creative responses adapted to local needs. But then, can decentralization and citizen participation live up to the faith and expectations that they have inspired? I argue that the literature commonly over-emphasises the role of citizen participation and decentralization in development and what these processes and reforms can achieve. Much of the evidence is anecdotal in nature and tends to neglect the specific contexts in which these processes take place. Also largely ignored are political economy considerations and a critical exploration of the relationship between these two key words. At best, when their interrelationships are addressed decentralization and citizen participation are conceived as based on a symbiotic relationship. I suggest, however, that the relationship between these two processes is not as straightforward as most of the literature assumes. The meanings of these two key words in current development lexicon are explored and critically assessed. I argue that whether or not the rising prominence of these two words actually means the emergence of a new development agenda is a moot point. It critically depends on the understandings of these ambiguous terms. The thesis adopts a political economy approach. Combined with this is an awareness of the broader historical and socio-economic context in which citizen participation and decentralization take place. The thesis applies these ideas triangulating diverse research methods and data sources. It combines a literature review and documentary analysis, a survey conducted with municipal authorities and civil society organizations in the Eastern Cape as well as structured interviews with Ward councillors and with key informants. From a theoretical perspective, the study lays a foundation for understanding the relationship between development policies outcomes and the nature of citizen participation and decentralization in developing countries. This, in turn, provides a basis from which citizen participation and decentralization in South Africa can be assessed and understood. The thesis presents evidence from a case study of the Eastern Cape, South Africa. By revealing how different dimensions of decentralization and citizen participation operate and intersect, the findings demonstrate, that contrary to common knowledge, citizen participation and decentralization are frequently at odds. Moreover, contrary to frequent statements, the research also shows that opening new spaces for participation in decentralized local governance can result in fewer changes and disappointing results at best, undermining the transformative potential of the concepts of participation and decentralization.
- Full Text:
- Date Issued: 2009
- Authors: Robino, Carolina
- Date: 2009
- Subjects: Local government -- Citizen participation , Decentralization in government -- South Africa , Political planning -- Citizen participation , Community development, Urban -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9084 , http://hdl.handle.net/10948/875 , Local government -- Citizen participation , Decentralization in government -- South Africa , Political planning -- Citizen participation , Community development, Urban -- South Africa -- Eastern Cape
- Description: Contemporary debates about development confer a prominent role to citizen participation and decentralization. Growing scepticism about the efficacy of narrowly conceived measures add pressure to reform development both theoretically and in practical terms. There is a greater understanding that ‘traditional’ development approaches and policies need to be reformulated and decentralization and citizen participation have been proposed as remedies to previous development failures. It is frequently argued that citizen participation will improve the efficiency and efficacy of public services. Citizen participation is meant to render local government more accountable and to contribute to deepening democracy, by reinforcing representative democratic institutions with participatory forms. At the same time, decentralization reforms have been proposed as a response to the failures of highly centralized states. From a political perspective, it is argued, decentralization reforms can help the central state gain legitimacy and have been seen as a strategy for maintaining political stability. It has been repeatedly suggested that physical proximity makes it easier for citizens to hold local officials accountable for their performance. From an economic perspective, decentralization can improve the match between the mix of services provided by the public sector and the preferences of the local population. It has also been noted that people are more willing to pay for services that respond to their priorities and that increased competition between local governments generates spaces for more creative responses adapted to local needs. But then, can decentralization and citizen participation live up to the faith and expectations that they have inspired? I argue that the literature commonly over-emphasises the role of citizen participation and decentralization in development and what these processes and reforms can achieve. Much of the evidence is anecdotal in nature and tends to neglect the specific contexts in which these processes take place. Also largely ignored are political economy considerations and a critical exploration of the relationship between these two key words. At best, when their interrelationships are addressed decentralization and citizen participation are conceived as based on a symbiotic relationship. I suggest, however, that the relationship between these two processes is not as straightforward as most of the literature assumes. The meanings of these two key words in current development lexicon are explored and critically assessed. I argue that whether or not the rising prominence of these two words actually means the emergence of a new development agenda is a moot point. It critically depends on the understandings of these ambiguous terms. The thesis adopts a political economy approach. Combined with this is an awareness of the broader historical and socio-economic context in which citizen participation and decentralization take place. The thesis applies these ideas triangulating diverse research methods and data sources. It combines a literature review and documentary analysis, a survey conducted with municipal authorities and civil society organizations in the Eastern Cape as well as structured interviews with Ward councillors and with key informants. From a theoretical perspective, the study lays a foundation for understanding the relationship between development policies outcomes and the nature of citizen participation and decentralization in developing countries. This, in turn, provides a basis from which citizen participation and decentralization in South Africa can be assessed and understood. The thesis presents evidence from a case study of the Eastern Cape, South Africa. By revealing how different dimensions of decentralization and citizen participation operate and intersect, the findings demonstrate, that contrary to common knowledge, citizen participation and decentralization are frequently at odds. Moreover, contrary to frequent statements, the research also shows that opening new spaces for participation in decentralized local governance can result in fewer changes and disappointing results at best, undermining the transformative potential of the concepts of participation and decentralization.
- Full Text:
- Date Issued: 2009
Qualitative and quantitative properties of solutions of ordinary differential equations
- Authors: Ogundare, Babatunde Sunday
- Date: 2009
- Subjects: Differential equations , Lyapunov functions , Chebyshev polynomials , Algorithms
- Language: English
- Type: Thesis , Doctoral , PhD (Applied Mathematics)
- Identifier: vital:11588 , http://hdl.handle.net/10353/244 , Differential equations , Lyapunov functions , Chebyshev polynomials , Algorithms
- Description: This thesis is concerned with the qualitative and quantitative properties of solutions of certain classes of ordinary di erential equations (ODEs); in particular linear boundary value problems of second order ODE's and non-linear ODEs of order at most four. The Lyapunov's second method of special functions called Lyapunov functions are employed extensively in this thesis. We construct suitable complete Lyapunov functions to discuss the qualitative properties of solutions to certain classes of non-linear ordinary di erential equations considered. Though there is no unique way of constructing Lyapunov functions, We adopt Cartwright's method to construct complete Lyapunov functions that are required in this thesis. Su cient conditions were established to discuss the qualitative properties such as boundedness, convergence, periodicity and stability of the classes of equations of our focus. Another aspect of this thesis is on the quantitative properties of solutions. New scheme based on interpolation and collocation is derived for solving initial value problem of ODEs. This scheme is derived from the general method of deriving the spline functions. Also by exploiting the Trigonometric identity property of the Chebyshev polynomials, We develop a new scheme for approximating the solutions of two-point boundary value problems. These schemes are user-friendly, easy to develop algorithm (computer program) and execute. They compare favorably with known standard methods used in solving the classes of problems they were derived for
- Full Text:
- Date Issued: 2009
- Authors: Ogundare, Babatunde Sunday
- Date: 2009
- Subjects: Differential equations , Lyapunov functions , Chebyshev polynomials , Algorithms
- Language: English
- Type: Thesis , Doctoral , PhD (Applied Mathematics)
- Identifier: vital:11588 , http://hdl.handle.net/10353/244 , Differential equations , Lyapunov functions , Chebyshev polynomials , Algorithms
- Description: This thesis is concerned with the qualitative and quantitative properties of solutions of certain classes of ordinary di erential equations (ODEs); in particular linear boundary value problems of second order ODE's and non-linear ODEs of order at most four. The Lyapunov's second method of special functions called Lyapunov functions are employed extensively in this thesis. We construct suitable complete Lyapunov functions to discuss the qualitative properties of solutions to certain classes of non-linear ordinary di erential equations considered. Though there is no unique way of constructing Lyapunov functions, We adopt Cartwright's method to construct complete Lyapunov functions that are required in this thesis. Su cient conditions were established to discuss the qualitative properties such as boundedness, convergence, periodicity and stability of the classes of equations of our focus. Another aspect of this thesis is on the quantitative properties of solutions. New scheme based on interpolation and collocation is derived for solving initial value problem of ODEs. This scheme is derived from the general method of deriving the spline functions. Also by exploiting the Trigonometric identity property of the Chebyshev polynomials, We develop a new scheme for approximating the solutions of two-point boundary value problems. These schemes are user-friendly, easy to develop algorithm (computer program) and execute. They compare favorably with known standard methods used in solving the classes of problems they were derived for
- Full Text:
- Date Issued: 2009
The management of physical resources by principals in the rural secondary schools of the Eastern Cape Province, South Africa
- Authors: Gumbi, Daphne
- Date: 2009
- Subjects: School facilities -- South Africa -- Eastern Cape , School buildings -- South Africa -- Eastern Cape , Rural schools -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9447 , http://hdl.handle.net/10948/911 , School facilities -- South Africa -- Eastern Cape , School buildings -- South Africa -- Eastern Cape , Rural schools -- South Africa -- Eastern Cape
- Description: This research study examined whether the physical resources in rural secondary schools are adequate and are managed properly by the school principals, for quality education to be achieved in the Eastern Cape Province. The dramatic changes in South Africa recognized that the future depends on an education system which develops the full potential of all learners. Although the Constitution of South Africa is advocating for equal education for all, there are disparities which are evident in the quality of the infrastructure, especially in remote rural areas where the fundamental requirements for effective education are lacking such as, water, electricity, sanitation and basic educational equipment. This shows that, although policy and legislative frameworks for transforming the education system have been put in place, managing the change is still a key challenge especially that of physical resources. Management of physical resources illustrates the problems facing principals by pointing to the lack of basic facilities in many rural secondary schools. In terms of the provision and management, many challenges remain, like most schools do not have adequate physical facilities. School buildings such as classrooms are inadequate or unsafe with no toilets, libraries, laboratories and many learners and teachers do not have learner teaching support materials (LTSMs). On the other hand, in terms of the Constitution, the Department of Education is responsible for bringing redress, equality and to upholding the Constitutional values such as shared decision-making, transparency, shared accountability and empowerment for equal partnership with other stakeholders. The physical resource management is one of the major responsibilities of principals. Their leadership is largely about ensuring that a clear and shared sense of direction is developed for both leadership and management. The school viii system meant that schools have moved nearer to the communities they serve and this has led to schools being more accountable to their communities. This study further investigated whether there is a significant correlation between the management of physical resources and quality education as well as the eradication of poverty in the rural secondary schools of the ECP. The proper execution of the management tasks of planning, organizing, leading, and controlling (POLC) by the principals have contributed extensively to the success of the schools. Therefore, this will mean that the act of managing physical resources through POLC and the process of working with or through SGBs, teachers, parents, learners, EDOs and the community at large to achieve set goals of education of relevance, excellence and quality education by effectively and efficiently using the physical resources in a school climate and environment that is collegial. The study showed that there is a link between management tasks (POLC) and collegial style of leadership in the school. The literature reviewed supported the view that the invitational style of leadership and collegiality increase the potential of a school to manage its physical resources economically, efficiently and effectively, particularly in a climate where the resource handlers take ownership of the school especially in remote rural settings. The 255 out of 300 subjects (85%) chosen to participate in this study were selected on the basis of their accessibility. Convenience sampling was used to conduct the study as this ensured that the population represented stakeholders that manage physical resources at schools, such as deputy principals, head of departments and teachers. Questionnaires were distributed, completed and collected personally. The questionnaires were analyzed and gaps such as the effects of lack of physical resources and how the learners’ profile were affected were reinforced by individual and group interviews that were semi-structured as ix well as participant observations from principals at O.R Tambo, Chris Hani and Amathole District Municipalities were conducted. It was deduced from the statistical data presented that there is a significant correlation between the principals’ management tasks and the quality of education. This shows that the more the principals blend properly planning, organizing, leading and control management tasks the more the physical resources will be managed better, that is, effectively, efficiently, economically and transparently and the less the bringing together of management tasks the less the meaningful management of physical resources will be. The study supported the hypothesis that a combination of management tasks performed by the principals positively influences the proper management of physical resources in rural secondary schools of ECP. The study rejects both null hypotheses that there is no significant correlation between planning, organising, leading and controlling as leadership functions of PRs and the quality of education in rural secondary schools of ECP as well as, that principals of rural secondary schools are not expected to possess adequate leadership knowledge and skills to effectively manage available PRs in their rural secondary schools. This study affirms the view that adequate physical resources are crucial as well as the appropriate management skills of principals for high quality education to be achieved in rural secondary schools. Without adequate physical resources, proper handling of the limited physical resources and the possession of management skills by principals, rural schools are less likely to succeed in their efforts to improve education.
- Full Text:
- Date Issued: 2009
- Authors: Gumbi, Daphne
- Date: 2009
- Subjects: School facilities -- South Africa -- Eastern Cape , School buildings -- South Africa -- Eastern Cape , Rural schools -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DEd
- Identifier: vital:9447 , http://hdl.handle.net/10948/911 , School facilities -- South Africa -- Eastern Cape , School buildings -- South Africa -- Eastern Cape , Rural schools -- South Africa -- Eastern Cape
- Description: This research study examined whether the physical resources in rural secondary schools are adequate and are managed properly by the school principals, for quality education to be achieved in the Eastern Cape Province. The dramatic changes in South Africa recognized that the future depends on an education system which develops the full potential of all learners. Although the Constitution of South Africa is advocating for equal education for all, there are disparities which are evident in the quality of the infrastructure, especially in remote rural areas where the fundamental requirements for effective education are lacking such as, water, electricity, sanitation and basic educational equipment. This shows that, although policy and legislative frameworks for transforming the education system have been put in place, managing the change is still a key challenge especially that of physical resources. Management of physical resources illustrates the problems facing principals by pointing to the lack of basic facilities in many rural secondary schools. In terms of the provision and management, many challenges remain, like most schools do not have adequate physical facilities. School buildings such as classrooms are inadequate or unsafe with no toilets, libraries, laboratories and many learners and teachers do not have learner teaching support materials (LTSMs). On the other hand, in terms of the Constitution, the Department of Education is responsible for bringing redress, equality and to upholding the Constitutional values such as shared decision-making, transparency, shared accountability and empowerment for equal partnership with other stakeholders. The physical resource management is one of the major responsibilities of principals. Their leadership is largely about ensuring that a clear and shared sense of direction is developed for both leadership and management. The school viii system meant that schools have moved nearer to the communities they serve and this has led to schools being more accountable to their communities. This study further investigated whether there is a significant correlation between the management of physical resources and quality education as well as the eradication of poverty in the rural secondary schools of the ECP. The proper execution of the management tasks of planning, organizing, leading, and controlling (POLC) by the principals have contributed extensively to the success of the schools. Therefore, this will mean that the act of managing physical resources through POLC and the process of working with or through SGBs, teachers, parents, learners, EDOs and the community at large to achieve set goals of education of relevance, excellence and quality education by effectively and efficiently using the physical resources in a school climate and environment that is collegial. The study showed that there is a link between management tasks (POLC) and collegial style of leadership in the school. The literature reviewed supported the view that the invitational style of leadership and collegiality increase the potential of a school to manage its physical resources economically, efficiently and effectively, particularly in a climate where the resource handlers take ownership of the school especially in remote rural settings. The 255 out of 300 subjects (85%) chosen to participate in this study were selected on the basis of their accessibility. Convenience sampling was used to conduct the study as this ensured that the population represented stakeholders that manage physical resources at schools, such as deputy principals, head of departments and teachers. Questionnaires were distributed, completed and collected personally. The questionnaires were analyzed and gaps such as the effects of lack of physical resources and how the learners’ profile were affected were reinforced by individual and group interviews that were semi-structured as ix well as participant observations from principals at O.R Tambo, Chris Hani and Amathole District Municipalities were conducted. It was deduced from the statistical data presented that there is a significant correlation between the principals’ management tasks and the quality of education. This shows that the more the principals blend properly planning, organizing, leading and control management tasks the more the physical resources will be managed better, that is, effectively, efficiently, economically and transparently and the less the bringing together of management tasks the less the meaningful management of physical resources will be. The study supported the hypothesis that a combination of management tasks performed by the principals positively influences the proper management of physical resources in rural secondary schools of ECP. The study rejects both null hypotheses that there is no significant correlation between planning, organising, leading and controlling as leadership functions of PRs and the quality of education in rural secondary schools of ECP as well as, that principals of rural secondary schools are not expected to possess adequate leadership knowledge and skills to effectively manage available PRs in their rural secondary schools. This study affirms the view that adequate physical resources are crucial as well as the appropriate management skills of principals for high quality education to be achieved in rural secondary schools. Without adequate physical resources, proper handling of the limited physical resources and the possession of management skills by principals, rural schools are less likely to succeed in their efforts to improve education.
- Full Text:
- Date Issued: 2009
Ethical decision-making in the therapeutic space : a psychoanalytic view
- Authors: Silove, Melanie
- Date: 2009
- Subjects: Decision making -- Moral and ethical aspects , Psychotherapy -- Moral and ethical aspects , Psychotherapists -- Professional ethics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3273 , http://hdl.handle.net/10962/d1020873
- Description: This study examined the ethical decision-making process as it transpired in the everyday context of the therapeutic space. In-depth interviews explored the subjective experiences of six South African psychologists, practicing as psychoanalytic psychotherapists, and their efforts to resolve real-life ethical dilemmas. The theoretical framework used to interpret the data subsumed professional literature in psychology on principle-based ethical decision-making as well as contemporary psychoanalytic debates on the phenomenon of countertransference enactments. A review of ethics codes, survey research and seminal decision-making frameworks suggests that ethical dilemmas have traditionally been resolved by recourse to an objective and impartial “principle ethics” perspective. Empirical evidence shows, however, that logical thinking and the rational application of codes, principles and standards are often insufficient to secure ethical action. The establishment of reflective space and the core theoretical notion of “ethical decision-making enactments” were proposed in order to address the subjective, irrational and unconscious dimension of professional decision-making. This study used a broadly hermeneutic research method which transformed participants‟ descriptions of engagement with real-life dilemmas into a psychoanalytically informed interpretive account of ethical decision-making. Twelve aspirational ethical principles were found to guide participants‟ daily analytic work. Beneficence was the principle most strongly identified with and nonmaleficence was the most neglected ethical principle. Unprocessed countertransference responses were shown to drive earlier prereflective phases of the ethical decision-making process. Mature ethical judgment was predicated upon the retrospective analysis of enactment phenomena. Dissatisfaction was expressed by all participants with regard to the role of professional resources in aiding the resolution of stressful ethical dilemmas. Risk factors for compromised professional decision-making included the paucity and perceived irrelevance of postgraduate ethics training, supervisory failure to confront the ethical and countertransference dimensions of common dilemmas and professional isolation. Rather than eliciting the hope of emotional support and greater insight, professional resources on the contrary mostly appeared to induce anxiety, mistrust and fearfulness. Based on the data and the literature, a pragmatic psychoanalytically informed ethical decision-making model was finally generated. The model, which considers both principle ethics as well as countertransference phenomena, offers a preliminary contribution to professional dialogue on the development and evaluation of empirically based decision-making frameworks. Practical recommendations are made for both the revision of the current South African ethics code and for improving the postqualifying ethics education of psychoanalytic practitioners and supervisors. The limitations of the data are discussed and directions for future research initiatives are proposed.
- Full Text:
- Date Issued: 2009
- Authors: Silove, Melanie
- Date: 2009
- Subjects: Decision making -- Moral and ethical aspects , Psychotherapy -- Moral and ethical aspects , Psychotherapists -- Professional ethics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3273 , http://hdl.handle.net/10962/d1020873
- Description: This study examined the ethical decision-making process as it transpired in the everyday context of the therapeutic space. In-depth interviews explored the subjective experiences of six South African psychologists, practicing as psychoanalytic psychotherapists, and their efforts to resolve real-life ethical dilemmas. The theoretical framework used to interpret the data subsumed professional literature in psychology on principle-based ethical decision-making as well as contemporary psychoanalytic debates on the phenomenon of countertransference enactments. A review of ethics codes, survey research and seminal decision-making frameworks suggests that ethical dilemmas have traditionally been resolved by recourse to an objective and impartial “principle ethics” perspective. Empirical evidence shows, however, that logical thinking and the rational application of codes, principles and standards are often insufficient to secure ethical action. The establishment of reflective space and the core theoretical notion of “ethical decision-making enactments” were proposed in order to address the subjective, irrational and unconscious dimension of professional decision-making. This study used a broadly hermeneutic research method which transformed participants‟ descriptions of engagement with real-life dilemmas into a psychoanalytically informed interpretive account of ethical decision-making. Twelve aspirational ethical principles were found to guide participants‟ daily analytic work. Beneficence was the principle most strongly identified with and nonmaleficence was the most neglected ethical principle. Unprocessed countertransference responses were shown to drive earlier prereflective phases of the ethical decision-making process. Mature ethical judgment was predicated upon the retrospective analysis of enactment phenomena. Dissatisfaction was expressed by all participants with regard to the role of professional resources in aiding the resolution of stressful ethical dilemmas. Risk factors for compromised professional decision-making included the paucity and perceived irrelevance of postgraduate ethics training, supervisory failure to confront the ethical and countertransference dimensions of common dilemmas and professional isolation. Rather than eliciting the hope of emotional support and greater insight, professional resources on the contrary mostly appeared to induce anxiety, mistrust and fearfulness. Based on the data and the literature, a pragmatic psychoanalytically informed ethical decision-making model was finally generated. The model, which considers both principle ethics as well as countertransference phenomena, offers a preliminary contribution to professional dialogue on the development and evaluation of empirically based decision-making frameworks. Practical recommendations are made for both the revision of the current South African ethics code and for improving the postqualifying ethics education of psychoanalytic practitioners and supervisors. The limitations of the data are discussed and directions for future research initiatives are proposed.
- Full Text:
- Date Issued: 2009
Bioconditioning and nitrogen fertility effects of selected cyanobacteria strains on two degraded soils in the Eastern Cape Province, South Africa
- Authors: Maqubela, Mfundo Phakama
- Date: 2009
- Subjects: Nostoc , Cyanobacteria , Soil fertility -- Testing , Soils -- Nitrogen content , Cyanobacteria -- Biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD (Soil Science)
- Identifier: vital:11959 , http://hdl.handle.net/10353/558 , Nostoc , Cyanobacteria , Soil fertility -- Testing , Soils -- Nitrogen content , Cyanobacteria -- Biotechnology
- Description: Some cyanobacteria strains have biofertilization and bioconditioning effects in soils. The objective of this study was to identify cyanobacteria with potential to improve the N fertility and structural stability of degraded soils and evaluate their effectiveness in soils of the Eastern Cape, South Africa. Isolation and characterization of the indigenous cyanobacteria strains with desirable properties was first to be undertaken because their effects are known to differ from strain to strain. Cyanobacteria strains 3g, 3v, and 7e were identified from 97 strains isolated from selected soils. Nostoc strains 3g and 3v had greater ability to produce exocellular polysaccharides (EPS) but low potential to fix atmospheric N2 (4.7 and 1.3 nmol C2H4 μg chl-1 h-1, respectively). On the other hand, strain 7e had the highest capability to fix atmospheric N2 (16.1 nmol C2H4 μg chl-1 h-1) but had the least ability to produce EPS. Evaluation of the strains was done in glasshouse studies starting with Nostoc strain 9v isolated from a Tanzanian soil, followed by the indigenous strains isolated from soils in Hertzog and Qunu, South Africa. Inoculation was done by uniformly applying cyanobacteria on the surface of potted soils at a rate of 6 g m-2. First harvest and soil sampling took place after six weeks, and the top 25 mm of the soil was mixed, replanted, and sampled again after a further six weeks (second harvest). Inoculation with Nostoc strain 9v increased soil N by 40 percent and 17 percent in Guquka and Hertzog soils, respectively, and consequently increased maize dry matter yields by 40 and 49 percent. Soil C increased by 27 percent and 8 percent in Guquka and Hertzog soils, respectively, and this increase was significantly associated with that of soil N (R2 = 0.838). Higher contents of soil C, soil N and mineral N, however, were found in non-cropped soils. Scanning Electron Microscopy (SEM) revealed coatings of EPS on soil particles and fragments of non-cropped inoculated soils, with iii other particles enmeshed in networks of filaments, in contrast to cropped and/or non-inoculated soils. The proportion of very stable aggregates was increased by inoculation but cropping with maize reduced the aggregate stability. Inoculating Hertzog soil with indigenous strains 3g and 7e increased the nitrate N in the first cropping by 49 percent and 69 percent respectively, in cropped soils. In the second cropping increases in mineral N were 41 percent and 43 percent in 3g and 7e inoculated soils, respectively. Maize dry matter yields were higher on inoculated soils both in the first and second harvest in response to the improved N status of the soil. Increases in aggregate MWD in cropped soil as determined by fast wetting, mechanical breakdown and slow wetting were 85 percent, 33 percent, 33 percent, respectively, for 3g inoculation, 64 percent, 41 percent, and 41 percent, respectively, for 7e inoculation and 60 percent, 24 percent, 50 percent for inoculation with 9v. In non-cropped soil, increases in MWD as determined by fast wetting, mechanical breakdown and slow wetting were 11 percent, 0 percent, 7 percent, respectively for 3g inoculation, 21 percent, 11 percent, and 7 percent, respectively for 7e inoculation, and 25 percent, 36 percent, and 19 percent for strain 9v inoculation. Scanning electron microscopy observations, which were confirmed by chemical results, revealed that inoculated soils had high EPS and filaments that encouraged soil aggregation and improved aggregate stability. Results of this study show that cyanobacteria strains isolated and selected for their ability to fix atmospheric N2 and produce EPS improved the fertility status and aggregate stability of degraded soils from South Africa.
- Full Text:
- Date Issued: 2009
- Authors: Maqubela, Mfundo Phakama
- Date: 2009
- Subjects: Nostoc , Cyanobacteria , Soil fertility -- Testing , Soils -- Nitrogen content , Cyanobacteria -- Biotechnology
- Language: English
- Type: Thesis , Doctoral , PhD (Soil Science)
- Identifier: vital:11959 , http://hdl.handle.net/10353/558 , Nostoc , Cyanobacteria , Soil fertility -- Testing , Soils -- Nitrogen content , Cyanobacteria -- Biotechnology
- Description: Some cyanobacteria strains have biofertilization and bioconditioning effects in soils. The objective of this study was to identify cyanobacteria with potential to improve the N fertility and structural stability of degraded soils and evaluate their effectiveness in soils of the Eastern Cape, South Africa. Isolation and characterization of the indigenous cyanobacteria strains with desirable properties was first to be undertaken because their effects are known to differ from strain to strain. Cyanobacteria strains 3g, 3v, and 7e were identified from 97 strains isolated from selected soils. Nostoc strains 3g and 3v had greater ability to produce exocellular polysaccharides (EPS) but low potential to fix atmospheric N2 (4.7 and 1.3 nmol C2H4 μg chl-1 h-1, respectively). On the other hand, strain 7e had the highest capability to fix atmospheric N2 (16.1 nmol C2H4 μg chl-1 h-1) but had the least ability to produce EPS. Evaluation of the strains was done in glasshouse studies starting with Nostoc strain 9v isolated from a Tanzanian soil, followed by the indigenous strains isolated from soils in Hertzog and Qunu, South Africa. Inoculation was done by uniformly applying cyanobacteria on the surface of potted soils at a rate of 6 g m-2. First harvest and soil sampling took place after six weeks, and the top 25 mm of the soil was mixed, replanted, and sampled again after a further six weeks (second harvest). Inoculation with Nostoc strain 9v increased soil N by 40 percent and 17 percent in Guquka and Hertzog soils, respectively, and consequently increased maize dry matter yields by 40 and 49 percent. Soil C increased by 27 percent and 8 percent in Guquka and Hertzog soils, respectively, and this increase was significantly associated with that of soil N (R2 = 0.838). Higher contents of soil C, soil N and mineral N, however, were found in non-cropped soils. Scanning Electron Microscopy (SEM) revealed coatings of EPS on soil particles and fragments of non-cropped inoculated soils, with iii other particles enmeshed in networks of filaments, in contrast to cropped and/or non-inoculated soils. The proportion of very stable aggregates was increased by inoculation but cropping with maize reduced the aggregate stability. Inoculating Hertzog soil with indigenous strains 3g and 7e increased the nitrate N in the first cropping by 49 percent and 69 percent respectively, in cropped soils. In the second cropping increases in mineral N were 41 percent and 43 percent in 3g and 7e inoculated soils, respectively. Maize dry matter yields were higher on inoculated soils both in the first and second harvest in response to the improved N status of the soil. Increases in aggregate MWD in cropped soil as determined by fast wetting, mechanical breakdown and slow wetting were 85 percent, 33 percent, 33 percent, respectively, for 3g inoculation, 64 percent, 41 percent, and 41 percent, respectively, for 7e inoculation and 60 percent, 24 percent, 50 percent for inoculation with 9v. In non-cropped soil, increases in MWD as determined by fast wetting, mechanical breakdown and slow wetting were 11 percent, 0 percent, 7 percent, respectively for 3g inoculation, 21 percent, 11 percent, and 7 percent, respectively for 7e inoculation, and 25 percent, 36 percent, and 19 percent for strain 9v inoculation. Scanning electron microscopy observations, which were confirmed by chemical results, revealed that inoculated soils had high EPS and filaments that encouraged soil aggregation and improved aggregate stability. Results of this study show that cyanobacteria strains isolated and selected for their ability to fix atmospheric N2 and produce EPS improved the fertility status and aggregate stability of degraded soils from South Africa.
- Full Text:
- Date Issued: 2009
Women in organisational management in Zimbabwe: theory and practice
- Authors: Zikhali, Whitehead
- Date: 2009
- Subjects: Businesswomen , Discrimination in employment -- Zimbabwe , Women executives -- Zimbabwe , Success in business -- Zimbabwe , Corporate culture -- Zimbabwe , Leadership -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD (Social Science Dev)
- Identifier: vital:11415 , http://hdl.handle.net/10353/d1001185 , Businesswomen , Discrimination in employment -- Zimbabwe , Women executives -- Zimbabwe , Success in business -- Zimbabwe , Corporate culture -- Zimbabwe , Leadership -- Zimbabwe
- Description: The study was premised on the truism that men have historically served in higher echelons of organizational management structures and women are under-represented. The principal objective was to explore the constraints faced by women in accessing higher leadership and senior management positions in public, private and non-governmental organisations in Zimbabwe. This study adopted the triangulation method, that is, qualitative and quantitative approaches. These mixed research methods, were upgraded by the feminist research methodologies, thereby making a contribution in the field of research. The study found out that the constraints that mostly hinder women from accessing leadership and senior management positions in public, private and NGOs were cultural practices, which represent levels of power and control that in turn hinder reforms; and women's socialisation into feminised roles. The study also found out that in most organisations, most females work under male leadership, and this traditional organisational culture, needs to be deconstructed and reversed in order to achieve gender equality. The study recommended for a human centric and integrated organizational management strategy for public, private and NGOs in Zimbabwe. The adoption of a human centric and integrated management approach should aim at gender equity and reduce women's under-representation. A human centred organizational culture has to be practiced, that would create organisational ethos that guide organizational management. An integrated organizational management approach should integrate all systems and processes into one complete framework, enabling people to work as a single unit, unified by organizational goals, shared vision and common values. The system should depend on a balanced mix of the masculine and feminine attributes. The approach should put its weight towards adoption of measures to attract, advance and empower women so as to benefit from their qualifications, experience and talent in a highly competitive environment.
- Full Text:
- Date Issued: 2009
- Authors: Zikhali, Whitehead
- Date: 2009
- Subjects: Businesswomen , Discrimination in employment -- Zimbabwe , Women executives -- Zimbabwe , Success in business -- Zimbabwe , Corporate culture -- Zimbabwe , Leadership -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD (Social Science Dev)
- Identifier: vital:11415 , http://hdl.handle.net/10353/d1001185 , Businesswomen , Discrimination in employment -- Zimbabwe , Women executives -- Zimbabwe , Success in business -- Zimbabwe , Corporate culture -- Zimbabwe , Leadership -- Zimbabwe
- Description: The study was premised on the truism that men have historically served in higher echelons of organizational management structures and women are under-represented. The principal objective was to explore the constraints faced by women in accessing higher leadership and senior management positions in public, private and non-governmental organisations in Zimbabwe. This study adopted the triangulation method, that is, qualitative and quantitative approaches. These mixed research methods, were upgraded by the feminist research methodologies, thereby making a contribution in the field of research. The study found out that the constraints that mostly hinder women from accessing leadership and senior management positions in public, private and NGOs were cultural practices, which represent levels of power and control that in turn hinder reforms; and women's socialisation into feminised roles. The study also found out that in most organisations, most females work under male leadership, and this traditional organisational culture, needs to be deconstructed and reversed in order to achieve gender equality. The study recommended for a human centric and integrated organizational management strategy for public, private and NGOs in Zimbabwe. The adoption of a human centric and integrated management approach should aim at gender equity and reduce women's under-representation. A human centred organizational culture has to be practiced, that would create organisational ethos that guide organizational management. An integrated organizational management approach should integrate all systems and processes into one complete framework, enabling people to work as a single unit, unified by organizational goals, shared vision and common values. The system should depend on a balanced mix of the masculine and feminine attributes. The approach should put its weight towards adoption of measures to attract, advance and empower women so as to benefit from their qualifications, experience and talent in a highly competitive environment.
- Full Text:
- Date Issued: 2009
Application of Baylis-Hillman methodology in the construction of complex heterocyclic targets
- Ganto, Mlungiseleli MacDonald
- Authors: Ganto, Mlungiseleli MacDonald
- Date: 2009
- Subjects: Heterocyclic compounds -- Derivatives Heterocyclic chemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4401 , http://hdl.handle.net/10962/d1006703
- Description: Baylis-Hillman reactions using various aromatic aldehydes, activated alkenes and catalysts have been used to: - access an extensive range of poly-heterocyclic products;explore chemoselectivity; and optimise reaction efficiency. Chromone-3-carbaldehydes and chromone-2-carbaldehydes, prepared via Vielsmeier-Haack and Kostanecki-Robinson methodology, respectively, have been used as Baylis-Hillman substrates with four different catalysts, viz., 1,4-diazabicyclo[2.2.2]octane (DABCO), 3-hydroxyquinuclidine (3-HQ), imidazole and N’,N’,N’,N’- tetramethylpropanediamine (TMPDA), and with methyl vinyl ketone (MVK), methyl acrylate, cyclic enones (2-cyclohexen-1-one, 2-cyclopenten-1-one and chromones) as activated alkenes. Reactions of the chromone- -carbaldehydes with MVK afforded dimeric Baylis-Hillman adducts when catalyzed by DABCO but when the same reactions were repeated using 3-HQ as catalyst, the dimeric products were accompanied by tricyclic Baylis-Hillman adducts. Use of excess MVK, however, led to mixtures of the normal Baylis-Hillman adducts and the tricyclic adducts – interestingly, with the apparent absence of the dimeric products. While reactions of chromone-3-carbaldehydes with methyl acrylate afforded the normal Baylis-Hillman adducts, the chromone-2- carbaldehydes produced, instead, rearrangement products, consistent with an earlier, single observation. Reactions of 2-nitrobenzaldehydes with cyclic enones using imidazole as catalyst afforded the normal Baylis-Hillman adducts, reductive cyclisation of the 2-cyclohexen-1- one and 2-cyclopenten-1-one adducts, using acetic acid and iron powder, afforded the corresponding quinoline erivatives. Treatment of cyclic enones with pyridine-2-carbaldehydes and quinoline-2-carbaldehydes using TMPDA as catalyst generally gave the expected Baylis-Hillman adducts. However, indolizine derivatives were isolated directly from Baylis-Hillman reactions involving pyridine-2-carbaldehydes and 2-cyclohexen-1-one. The remaining Baylis-Hillman adducts were cyclized to the corresponding indolizines by treatment with acetic anhydride both under reflux and under microwave-assisted conditions, the latter approach providing remarkably rapid and efficient access to the polycyclic products. Computer modelling studies have been conducted on selected polycyclic products at the Molecular Mechanics (MM), Quantum Mechanical (QM) and Density Functional (DFT) levels. The theoretical results have been used to calculate UV, IR and NMR absorption data, which have been compared, in turn, with the experimental spectroscopic data. Use has also been made of the estreNova NMR prediction programme and, generally, good agreement has been observed between the predicted and experimental spectroscopic data.
- Full Text:
- Date Issued: 2009
- Authors: Ganto, Mlungiseleli MacDonald
- Date: 2009
- Subjects: Heterocyclic compounds -- Derivatives Heterocyclic chemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4401 , http://hdl.handle.net/10962/d1006703
- Description: Baylis-Hillman reactions using various aromatic aldehydes, activated alkenes and catalysts have been used to: - access an extensive range of poly-heterocyclic products;explore chemoselectivity; and optimise reaction efficiency. Chromone-3-carbaldehydes and chromone-2-carbaldehydes, prepared via Vielsmeier-Haack and Kostanecki-Robinson methodology, respectively, have been used as Baylis-Hillman substrates with four different catalysts, viz., 1,4-diazabicyclo[2.2.2]octane (DABCO), 3-hydroxyquinuclidine (3-HQ), imidazole and N’,N’,N’,N’- tetramethylpropanediamine (TMPDA), and with methyl vinyl ketone (MVK), methyl acrylate, cyclic enones (2-cyclohexen-1-one, 2-cyclopenten-1-one and chromones) as activated alkenes. Reactions of the chromone- -carbaldehydes with MVK afforded dimeric Baylis-Hillman adducts when catalyzed by DABCO but when the same reactions were repeated using 3-HQ as catalyst, the dimeric products were accompanied by tricyclic Baylis-Hillman adducts. Use of excess MVK, however, led to mixtures of the normal Baylis-Hillman adducts and the tricyclic adducts – interestingly, with the apparent absence of the dimeric products. While reactions of chromone-3-carbaldehydes with methyl acrylate afforded the normal Baylis-Hillman adducts, the chromone-2- carbaldehydes produced, instead, rearrangement products, consistent with an earlier, single observation. Reactions of 2-nitrobenzaldehydes with cyclic enones using imidazole as catalyst afforded the normal Baylis-Hillman adducts, reductive cyclisation of the 2-cyclohexen-1- one and 2-cyclopenten-1-one adducts, using acetic acid and iron powder, afforded the corresponding quinoline erivatives. Treatment of cyclic enones with pyridine-2-carbaldehydes and quinoline-2-carbaldehydes using TMPDA as catalyst generally gave the expected Baylis-Hillman adducts. However, indolizine derivatives were isolated directly from Baylis-Hillman reactions involving pyridine-2-carbaldehydes and 2-cyclohexen-1-one. The remaining Baylis-Hillman adducts were cyclized to the corresponding indolizines by treatment with acetic anhydride both under reflux and under microwave-assisted conditions, the latter approach providing remarkably rapid and efficient access to the polycyclic products. Computer modelling studies have been conducted on selected polycyclic products at the Molecular Mechanics (MM), Quantum Mechanical (QM) and Density Functional (DFT) levels. The theoretical results have been used to calculate UV, IR and NMR absorption data, which have been compared, in turn, with the experimental spectroscopic data. Use has also been made of the estreNova NMR prediction programme and, generally, good agreement has been observed between the predicted and experimental spectroscopic data.
- Full Text:
- Date Issued: 2009
Evaluation of a plant-herbivore system in determining potential efficacy of a candidate biological control agent, cornops aquaticum for water hyacinth, eichhornia crassipes
- Authors: Bownes, Angela
- Date: 2009
- Subjects: Water hyacinth -- Control -- South Africa , Eichhornia crassipedes , Pontederiaceae , Grasshoppers , Biological pest control agents -- South Africa , Weeds -- Biological control -- South Africa , Invasive plants -- Biological control -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5687 , http://hdl.handle.net/10962/d1005373
- Description: Water hyacinth, Eichhornia crassipes Mart. Solms-Laubach (Pontederiaceae), a freefloating aquatic macrophyte of Neotropical origin, was introduced into South Africa as an ornamental aquarium plant in the early 1900’s. By the 1970’s it had reached pest proportions in dams and rivers around the country. Due to the sustainability, cost efficiency and low environmental risk associated with biological control, this has been a widely used method in an attempt to reduce infestations to below the threshold where they cause economic and ecological damage. To date, five arthropod and one pathogen biocontrol agents have been introduced for the control of water hyacinth but their impact has been variable. It is believed that their efficacy is hampered by the presence of highly eutrophic systems in South Africa in which plant growth is prolific and the negative effects of herbivory are therefore mitigated. It is for these reasons that new, potentially more damaging biocontrol agents are being considered for release. The water hyacinth grasshopper, Cornops aquaticum Brüner (Orthoptera: Acrididae), which is native to South America and Mexico, was brought into quarantine in Pretoria, South Africa in 1995. Although the grasshopper was identified as one of the most damaging insects associated with water hyacinth in its native range, it has not been considered as a biocontrol agent for water hyacinth anywhere else in the world. After extensive host-range testing which revealed it to be safe for release, a release permit for this candidate agent was issued in 2007. However, host specificity testing is no longer considered to be the only important component of pre-release screening of candidate biocontrol agents. Investigating biological and ecological aspects of the plant-herbivore system that will assist in determination of potential establishment, efficacy and the ability to build up good populations in the recipient environment are some of the important factors. This thesis is a pre-release evaluation of C. aquaticum to determine whether it is sufficiently damaging to water hyacinth to warrant its release. It investigated interactions between the grasshopper and water hyacinth under a range of nutrient conditions found in South African water bodies as well as the impact of the grasshopper on the competitive performance of water hyacinth. Both plant growth rates and the response of water hyacinth to herbivory by the grasshopper were influenced by nutrient availability to the plants. The ability of water hyacinth to compensate for loss of tissue through herbivory was greater under eutrophic nutrient conditions. However, a negative linear relationship was found between grasshopper biomass and water hyacinth performance parameters such as biomass accumulation and leaf production, even under eutrophic conditions. Water hyacinth’s compensatory ability in terms of its potential to mitigate to detrimental effects of insect feeding was dependent on the amount of damage caused by herbivory by the grasshopper. Plant biomass and the competitive ability of water hyacinth in relation to another freefloating aquatic weed species were reduced by C. aquaticum under eutrophic nutrient conditions, in a short space of time. It was also found that grasshopper feeding and characteristics related to their population dynamics such as fecundity and survival were significantly influenced by water nutrient availability and that environmental nutrient availability will influence the control potential of this species should it be released in South Africa. Cornops aquaticum shows promise as a biocontrol agent for water hyacinth but additional factors that were not investigated in this study such as compatibility with the South African climate and the current water hyacinth biocontrol agents need to be combined with these data to make a decision on its release. Possible management options for this species if it is to be introduced into South Africa are discussed.
- Full Text:
- Date Issued: 2009
- Authors: Bownes, Angela
- Date: 2009
- Subjects: Water hyacinth -- Control -- South Africa , Eichhornia crassipedes , Pontederiaceae , Grasshoppers , Biological pest control agents -- South Africa , Weeds -- Biological control -- South Africa , Invasive plants -- Biological control -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5687 , http://hdl.handle.net/10962/d1005373
- Description: Water hyacinth, Eichhornia crassipes Mart. Solms-Laubach (Pontederiaceae), a freefloating aquatic macrophyte of Neotropical origin, was introduced into South Africa as an ornamental aquarium plant in the early 1900’s. By the 1970’s it had reached pest proportions in dams and rivers around the country. Due to the sustainability, cost efficiency and low environmental risk associated with biological control, this has been a widely used method in an attempt to reduce infestations to below the threshold where they cause economic and ecological damage. To date, five arthropod and one pathogen biocontrol agents have been introduced for the control of water hyacinth but their impact has been variable. It is believed that their efficacy is hampered by the presence of highly eutrophic systems in South Africa in which plant growth is prolific and the negative effects of herbivory are therefore mitigated. It is for these reasons that new, potentially more damaging biocontrol agents are being considered for release. The water hyacinth grasshopper, Cornops aquaticum Brüner (Orthoptera: Acrididae), which is native to South America and Mexico, was brought into quarantine in Pretoria, South Africa in 1995. Although the grasshopper was identified as one of the most damaging insects associated with water hyacinth in its native range, it has not been considered as a biocontrol agent for water hyacinth anywhere else in the world. After extensive host-range testing which revealed it to be safe for release, a release permit for this candidate agent was issued in 2007. However, host specificity testing is no longer considered to be the only important component of pre-release screening of candidate biocontrol agents. Investigating biological and ecological aspects of the plant-herbivore system that will assist in determination of potential establishment, efficacy and the ability to build up good populations in the recipient environment are some of the important factors. This thesis is a pre-release evaluation of C. aquaticum to determine whether it is sufficiently damaging to water hyacinth to warrant its release. It investigated interactions between the grasshopper and water hyacinth under a range of nutrient conditions found in South African water bodies as well as the impact of the grasshopper on the competitive performance of water hyacinth. Both plant growth rates and the response of water hyacinth to herbivory by the grasshopper were influenced by nutrient availability to the plants. The ability of water hyacinth to compensate for loss of tissue through herbivory was greater under eutrophic nutrient conditions. However, a negative linear relationship was found between grasshopper biomass and water hyacinth performance parameters such as biomass accumulation and leaf production, even under eutrophic conditions. Water hyacinth’s compensatory ability in terms of its potential to mitigate to detrimental effects of insect feeding was dependent on the amount of damage caused by herbivory by the grasshopper. Plant biomass and the competitive ability of water hyacinth in relation to another freefloating aquatic weed species were reduced by C. aquaticum under eutrophic nutrient conditions, in a short space of time. It was also found that grasshopper feeding and characteristics related to their population dynamics such as fecundity and survival were significantly influenced by water nutrient availability and that environmental nutrient availability will influence the control potential of this species should it be released in South Africa. Cornops aquaticum shows promise as a biocontrol agent for water hyacinth but additional factors that were not investigated in this study such as compatibility with the South African climate and the current water hyacinth biocontrol agents need to be combined with these data to make a decision on its release. Possible management options for this species if it is to be introduced into South Africa are discussed.
- Full Text:
- Date Issued: 2009
Immobilization of catalyst in a wall-coated micro-structured reactor for gas/liquid oxidation of p-cymene
- Authors: Makgwane, Peter Ramashadi
- Date: 2009
- Subjects: Oxidation , Cymene
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10389 , http://hdl.handle.net/10948/1182 , Oxidation , Cymene
- Description: The selective, liquid phase oxidation of p-cymene is an important synthetic route for the production of p-cresol via the tertiary cymene hydroperoxide (TCHP). The industrial-scale oxidation process is characterised by slow oxidation rates due to limitations in the mass transfer of oxidant (gaseous oxygen) into the liquid phase. However, like all other autoxidation reactions, the oxidation reaction is exothermic, following the typical free radical autoxidation reaction mechanism, which implies that careful temperature control is critical in order to prevent the further reaction of the initially formed hydroperoxide species. In the presence of metal catalysts, the limiting oxidation rate is the transfer of oxygen from the gas to liquid boundary interface. As a result, low product yields and poor productivity space-time yield are typically experienced. At high substrate conversions, by-products resulting from the decomposition of the formed hydroperoxides predominate. For this reason, the conversion of substrate is restricted to preserve the TCHP selectivity. The slow rates in industrial-scale p-cymene oxidations results in long oxidation times, typically 8-12 h. Substrate conversions are typically between 15-20 percent, and the TCHP selectivity ranges between 65-70 percent. The work described in this thesis concerns the oxidation of p-cymene in a microstructured falling film reactor (FFMSR). These reactor systems facilitate chemical reactors to have high mass and heat transfer rates because of high surface area-to-volume ratios. Due to their small internal volumes, these reactors are inherently safe to operate. These properties were exploited to improve the p-cymene oxidation rate and, consequently, the space-time yield. In order to evaluate the suitability of vanadium phosphate oxide (VPO) catalysts for use as supported catalyst in the FFMSR, different catalysts prepared from VOHPO4∙0.5H2O and VO(H2PO4)2 precursors was first evaluated for the oxidation of p-cymene in a well-stirred batch reactor. The results of the two activated catalysts, (VO)2P2O7 and VO(PO3)2 when used as powders in their pure form, showed a significant improvement in p-cymene oxidation rates with conversions up to 40 percent in 3-4 h reaction time with a TCHP selectivity of 75-80 percent. The (VO)2P2O7 catalyst showed better oxidation rates and selectivity when compared to the VO(PO3)2 catalyst obtained from the VO(H2PO4)2 precursor. The (VO)2P2O7 catalyst was supported on a stainless steel plate and the coated plate used to study the long-term stability and catalytic perfornance of the catalyst during p-cymene oxidations in a batch reactor. Comparable oxidation rates and TCHP selectivity were obtained with the stainless steel coated VPO catalyst when compared to the “free powder” (VO)2P2O7 catalyst. The results also showed that the stainless steel coated catalyst displays a slow, yet significant deactivation over extended reaction periods (250 h onstream). Characterization of the exposed (VO)2P2O7 catalyst to p-cymene oxidation conditions by powder XRD, SEM and TGA-MS showed that (VO)2P2O7 phase undergoes structural transformation back to VOHPO4∙0.5H2O phase over time. The (VO)2P2O7/-Al2O3 catalyst was used to coat the micro-channel reaction plates of the FFMSR. Both uncoated and coated micro-channel reaction plates were evaluated in the FFMSR for the oxidation of p-cymene. The FFMSR showed effective improvement of oxidation rates in terms of productivity space-time-yield at comparable batch p-cymene conversions. A Typical 10 percent conversion in catalysed batch oxidations at 1-2 h reaction time was achieved in few seconds (19 s) reaction time in FFMSR. The comparison of uncoated (i.e. uncatalysed) and coated (i.e. catalysed) FFMSR oxidations showed slight differences in oxidation rates. No clear explanation could be established with the present results for the observed same behaviour. However, the insufficient contact time between the gas and liquid reactants with the wall-coated solid catalyst is one of the possible causes for the observed behaviour of the coated and uncoated micro-channel plates. A simple developed kinetic model was used to confirm the obtained batch oxidation results using cumene as probe compound due to its similarity to p-cumene oxidation and extensive studied kinetics. With the estimated K values and available rate constants from literature, it was possible to predict the conversions in a batch reactor at the same typical micro-structured reactor residence time (i.e. of 19 s). The predicted conversions in the batch reactor were less than 0.1 percent even at harsh conditions such as 170 oC when compared to about 10 percent achieved in the micro-structured reactor at the same reaction temperature, reactants concentration and reaction time of 19 s. This difference in the reactor systems performance indicates the unique advantages offered by micro-structured reactors (e.g. improved mass transfer, temperature management and high surface-to-volume ratios) to perform typical gas/liquid mass transfer limited reactions such as cumene and p-cymene autoxidations.
- Full Text:
- Date Issued: 2009
- Authors: Makgwane, Peter Ramashadi
- Date: 2009
- Subjects: Oxidation , Cymene
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:10389 , http://hdl.handle.net/10948/1182 , Oxidation , Cymene
- Description: The selective, liquid phase oxidation of p-cymene is an important synthetic route for the production of p-cresol via the tertiary cymene hydroperoxide (TCHP). The industrial-scale oxidation process is characterised by slow oxidation rates due to limitations in the mass transfer of oxidant (gaseous oxygen) into the liquid phase. However, like all other autoxidation reactions, the oxidation reaction is exothermic, following the typical free radical autoxidation reaction mechanism, which implies that careful temperature control is critical in order to prevent the further reaction of the initially formed hydroperoxide species. In the presence of metal catalysts, the limiting oxidation rate is the transfer of oxygen from the gas to liquid boundary interface. As a result, low product yields and poor productivity space-time yield are typically experienced. At high substrate conversions, by-products resulting from the decomposition of the formed hydroperoxides predominate. For this reason, the conversion of substrate is restricted to preserve the TCHP selectivity. The slow rates in industrial-scale p-cymene oxidations results in long oxidation times, typically 8-12 h. Substrate conversions are typically between 15-20 percent, and the TCHP selectivity ranges between 65-70 percent. The work described in this thesis concerns the oxidation of p-cymene in a microstructured falling film reactor (FFMSR). These reactor systems facilitate chemical reactors to have high mass and heat transfer rates because of high surface area-to-volume ratios. Due to their small internal volumes, these reactors are inherently safe to operate. These properties were exploited to improve the p-cymene oxidation rate and, consequently, the space-time yield. In order to evaluate the suitability of vanadium phosphate oxide (VPO) catalysts for use as supported catalyst in the FFMSR, different catalysts prepared from VOHPO4∙0.5H2O and VO(H2PO4)2 precursors was first evaluated for the oxidation of p-cymene in a well-stirred batch reactor. The results of the two activated catalysts, (VO)2P2O7 and VO(PO3)2 when used as powders in their pure form, showed a significant improvement in p-cymene oxidation rates with conversions up to 40 percent in 3-4 h reaction time with a TCHP selectivity of 75-80 percent. The (VO)2P2O7 catalyst showed better oxidation rates and selectivity when compared to the VO(PO3)2 catalyst obtained from the VO(H2PO4)2 precursor. The (VO)2P2O7 catalyst was supported on a stainless steel plate and the coated plate used to study the long-term stability and catalytic perfornance of the catalyst during p-cymene oxidations in a batch reactor. Comparable oxidation rates and TCHP selectivity were obtained with the stainless steel coated VPO catalyst when compared to the “free powder” (VO)2P2O7 catalyst. The results also showed that the stainless steel coated catalyst displays a slow, yet significant deactivation over extended reaction periods (250 h onstream). Characterization of the exposed (VO)2P2O7 catalyst to p-cymene oxidation conditions by powder XRD, SEM and TGA-MS showed that (VO)2P2O7 phase undergoes structural transformation back to VOHPO4∙0.5H2O phase over time. The (VO)2P2O7/-Al2O3 catalyst was used to coat the micro-channel reaction plates of the FFMSR. Both uncoated and coated micro-channel reaction plates were evaluated in the FFMSR for the oxidation of p-cymene. The FFMSR showed effective improvement of oxidation rates in terms of productivity space-time-yield at comparable batch p-cymene conversions. A Typical 10 percent conversion in catalysed batch oxidations at 1-2 h reaction time was achieved in few seconds (19 s) reaction time in FFMSR. The comparison of uncoated (i.e. uncatalysed) and coated (i.e. catalysed) FFMSR oxidations showed slight differences in oxidation rates. No clear explanation could be established with the present results for the observed same behaviour. However, the insufficient contact time between the gas and liquid reactants with the wall-coated solid catalyst is one of the possible causes for the observed behaviour of the coated and uncoated micro-channel plates. A simple developed kinetic model was used to confirm the obtained batch oxidation results using cumene as probe compound due to its similarity to p-cumene oxidation and extensive studied kinetics. With the estimated K values and available rate constants from literature, it was possible to predict the conversions in a batch reactor at the same typical micro-structured reactor residence time (i.e. of 19 s). The predicted conversions in the batch reactor were less than 0.1 percent even at harsh conditions such as 170 oC when compared to about 10 percent achieved in the micro-structured reactor at the same reaction temperature, reactants concentration and reaction time of 19 s. This difference in the reactor systems performance indicates the unique advantages offered by micro-structured reactors (e.g. improved mass transfer, temperature management and high surface-to-volume ratios) to perform typical gas/liquid mass transfer limited reactions such as cumene and p-cymene autoxidations.
- Full Text:
- Date Issued: 2009
The development and evaluation of gaze selection techniques
- Authors: Van Tonder, Martin Stephen
- Date: 2009
- Subjects: Human-computer interaction , User interfaces (Computer systems) , Gaze
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10469 , http://hdl.handle.net/10948/882 , Human-computer interaction , User interfaces (Computer systems) , Gaze
- Description: Eye gaze interaction enables users to interact with computers using their eyes. A wide variety of eye gaze interaction techniques have been developed to support this type of interaction. Gaze selection techniques, a class of eye gaze interaction techniques which support target selection, are the subject of this research. Researchers developing these techniques face a number of challenges. The most significant challenge is the limited accuracy of eye tracking equipment (due to the properties of the human eye). The design of gaze selection techniques is dominated by this constraint. Despite decades of research, existing techniques are still significantly less accurate than the mouse. A recently developed technique, EyePoint, represents the state of the art in gaze selection techniques. EyePoint combines gaze input with keyboard input. Evaluation results for this technique are encouraging, but accuracy is still a concern. Early trigger errors, resulting from users triggering a selection before looking at the intended target, were found to be the most commonly occurring errors for this technique. The primary goal of this research was to improve the usability of gaze selection techniques. In order to achieve this goal, novel gaze selection techniques were developed. New techniques were developed by combining elements of existing techniques in novel ways. Seven novel gaze selection techniques were developed. Three of these techniques were selected for evaluation. A software framework was developed for implementing and evaluating gaze selection techniques. This framework was used to implement the gaze selection techniques developed during this research. Implementing and evaluating all of the techniques using a common framework ensured consistency when comparing the techniques. The novel techniques which were developed were evaluated against EyePoint and the mouse using the framework. The three novel techniques evaluated were named TargetPoint, StaggerPoint and ScanPoint. TargetPoint combines motor space expansion with a visual feedback highlight whereas the StaggerPoint and TargetPoint designs explore novel approaches to target selection disambiguation. A usability evaluation of the three novel techniques alongside EyePoint and the mouse revealed some interesting trends. TargetPoint was found to be more usable and accurate than EyePoint. This novel technique also proved more popular with test participants. One aspect of TargetPoint which proved particularly popular was the visual feedback highlight, a feature which was found to be a more effective method of combating early trigger errors than existing approaches. StaggerPoint was more efficient than EyePoint, but was less effective and satisfying. ScanPoint was the least popular technique. The benefits of providing a visual feedback highlight and test participants' positive views thereof contradict views expressed in existing research regarding the usability of visual feedback. These results have implications for the design of future gaze selection techniques. A set of design principles was developed for designing new gaze selection techniques. The designers of gaze selection techniques can benefit from these design principles by applying them to their techniques
- Full Text:
- Date Issued: 2009
- Authors: Van Tonder, Martin Stephen
- Date: 2009
- Subjects: Human-computer interaction , User interfaces (Computer systems) , Gaze
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10469 , http://hdl.handle.net/10948/882 , Human-computer interaction , User interfaces (Computer systems) , Gaze
- Description: Eye gaze interaction enables users to interact with computers using their eyes. A wide variety of eye gaze interaction techniques have been developed to support this type of interaction. Gaze selection techniques, a class of eye gaze interaction techniques which support target selection, are the subject of this research. Researchers developing these techniques face a number of challenges. The most significant challenge is the limited accuracy of eye tracking equipment (due to the properties of the human eye). The design of gaze selection techniques is dominated by this constraint. Despite decades of research, existing techniques are still significantly less accurate than the mouse. A recently developed technique, EyePoint, represents the state of the art in gaze selection techniques. EyePoint combines gaze input with keyboard input. Evaluation results for this technique are encouraging, but accuracy is still a concern. Early trigger errors, resulting from users triggering a selection before looking at the intended target, were found to be the most commonly occurring errors for this technique. The primary goal of this research was to improve the usability of gaze selection techniques. In order to achieve this goal, novel gaze selection techniques were developed. New techniques were developed by combining elements of existing techniques in novel ways. Seven novel gaze selection techniques were developed. Three of these techniques were selected for evaluation. A software framework was developed for implementing and evaluating gaze selection techniques. This framework was used to implement the gaze selection techniques developed during this research. Implementing and evaluating all of the techniques using a common framework ensured consistency when comparing the techniques. The novel techniques which were developed were evaluated against EyePoint and the mouse using the framework. The three novel techniques evaluated were named TargetPoint, StaggerPoint and ScanPoint. TargetPoint combines motor space expansion with a visual feedback highlight whereas the StaggerPoint and TargetPoint designs explore novel approaches to target selection disambiguation. A usability evaluation of the three novel techniques alongside EyePoint and the mouse revealed some interesting trends. TargetPoint was found to be more usable and accurate than EyePoint. This novel technique also proved more popular with test participants. One aspect of TargetPoint which proved particularly popular was the visual feedback highlight, a feature which was found to be a more effective method of combating early trigger errors than existing approaches. StaggerPoint was more efficient than EyePoint, but was less effective and satisfying. ScanPoint was the least popular technique. The benefits of providing a visual feedback highlight and test participants' positive views thereof contradict views expressed in existing research regarding the usability of visual feedback. These results have implications for the design of future gaze selection techniques. A set of design principles was developed for designing new gaze selection techniques. The designers of gaze selection techniques can benefit from these design principles by applying them to their techniques
- Full Text:
- Date Issued: 2009
Bare life in the Bantustans (of the Eastern Cape): re-membering the centinnial South African nation-state
- Authors: Westaway, Ashley
- Date: 2009
- Subjects: Democracy -- South Africa , Homelands (South Africa) , Apartheid -- South Africa , Right of property -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD (History)
- Identifier: vital:11535 , http://hdl.handle.net/10353/149 , Democracy -- South Africa , Homelands (South Africa) , Apartheid -- South Africa , Right of property -- South Africa
- Description: This thesis argues that 1994 did not mark a point of absolute discontinuity in the history of South Africa. More specifically, it asserts that 1994 did not signal the end of segregationism; instead of democracy leading to national integration, the Bantustans are still governed and managed differently from the rest of the country. Consequently, it is no surprise that they remain mired in pervasive, debilitating poverty fifteen years after 1994. In insisting that contemporary South Africa is old (rather than new), the thesis seeks to make a contribution to political struggles that aim to bring to an end the segregationist past-in-the-present. The thesis is arranged in seven chapters. The first chapter considers the crisis that has engulfed South Africa historiography since 1994. It traces the roots of the crisis back to some of the fundamentals of the discipline of history, such as empiricism, neutrality and historicism. It suggests that the way to end the crisis, to re-assert the relevance of history, is for historians to re-invoke the practice of producing histories of the present, in an interested, deliberate manner. Chapter 2 narrows down the focus of the thesis to (past and present) property. It suggests that instead of understanding the constitutional protection of property rights and installation of a restitution process as the product of a compromise between adversarial negotiators, these outcomes are more correctly understood as emanating from consensus. The third chapter outlines the implementation of the restitution programme from 1994 to 2008. The productive value of restitution over this period is found not in what it has delivered to the claimants (supposedly the beneficiaries of the programme), but rather in its discursive effects related to citizenship in the new South Africa. Chapter 4 considers the exclusion of dispossession that was implemented in the Bantustans from the restitution programme. It argues that this decision was not an oversight on the part of the post-1994 government. Instead it was consistent with all other key policy decisions taken in the recent period. The Bantustans have been treated differently from the rest of South Africa; they have been deliberately under-developed, fabricated as welfare zones, and subjected to arbitrary customary rule. Whereas Chapters 2 to 4 look at the production of historical truth on the side of domination, Chapter 6 and 7 consider production on the side of resistance. Specifically, they describe and analyse the attempts of an NGO to establish the truths of betterment as dispossession, and post-1994 prejudice against the victims of betterment dispossession. They serve as case studies of third party-led processes that seek to produce truth-effects from within a prevailing truth regime. The final chapter attempts to bring many of the threads that weave through the thesis together, by means of a critical consideration of human rights discourse. The chapter calls on intellectuals to establish truths in relation to the history of ongoing human wrongs in South Africa (as opposed to the rainbow narrative of human rights) Finally, the thesis includes a postscript, comprising technical summaries of each of the chapters.
- Full Text:
- Date Issued: 2009
- Authors: Westaway, Ashley
- Date: 2009
- Subjects: Democracy -- South Africa , Homelands (South Africa) , Apartheid -- South Africa , Right of property -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD (History)
- Identifier: vital:11535 , http://hdl.handle.net/10353/149 , Democracy -- South Africa , Homelands (South Africa) , Apartheid -- South Africa , Right of property -- South Africa
- Description: This thesis argues that 1994 did not mark a point of absolute discontinuity in the history of South Africa. More specifically, it asserts that 1994 did not signal the end of segregationism; instead of democracy leading to national integration, the Bantustans are still governed and managed differently from the rest of the country. Consequently, it is no surprise that they remain mired in pervasive, debilitating poverty fifteen years after 1994. In insisting that contemporary South Africa is old (rather than new), the thesis seeks to make a contribution to political struggles that aim to bring to an end the segregationist past-in-the-present. The thesis is arranged in seven chapters. The first chapter considers the crisis that has engulfed South Africa historiography since 1994. It traces the roots of the crisis back to some of the fundamentals of the discipline of history, such as empiricism, neutrality and historicism. It suggests that the way to end the crisis, to re-assert the relevance of history, is for historians to re-invoke the practice of producing histories of the present, in an interested, deliberate manner. Chapter 2 narrows down the focus of the thesis to (past and present) property. It suggests that instead of understanding the constitutional protection of property rights and installation of a restitution process as the product of a compromise between adversarial negotiators, these outcomes are more correctly understood as emanating from consensus. The third chapter outlines the implementation of the restitution programme from 1994 to 2008. The productive value of restitution over this period is found not in what it has delivered to the claimants (supposedly the beneficiaries of the programme), but rather in its discursive effects related to citizenship in the new South Africa. Chapter 4 considers the exclusion of dispossession that was implemented in the Bantustans from the restitution programme. It argues that this decision was not an oversight on the part of the post-1994 government. Instead it was consistent with all other key policy decisions taken in the recent period. The Bantustans have been treated differently from the rest of South Africa; they have been deliberately under-developed, fabricated as welfare zones, and subjected to arbitrary customary rule. Whereas Chapters 2 to 4 look at the production of historical truth on the side of domination, Chapter 6 and 7 consider production on the side of resistance. Specifically, they describe and analyse the attempts of an NGO to establish the truths of betterment as dispossession, and post-1994 prejudice against the victims of betterment dispossession. They serve as case studies of third party-led processes that seek to produce truth-effects from within a prevailing truth regime. The final chapter attempts to bring many of the threads that weave through the thesis together, by means of a critical consideration of human rights discourse. The chapter calls on intellectuals to establish truths in relation to the history of ongoing human wrongs in South Africa (as opposed to the rainbow narrative of human rights) Finally, the thesis includes a postscript, comprising technical summaries of each of the chapters.
- Full Text:
- Date Issued: 2009