A common analysis framework for simulated streaming-video networks
- Authors: Mulumba, Patrick
- Date: 2009
- Subjects: Computer networks -- Management , Streaming video , Mass media -- Technological innovations
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4590 , http://hdl.handle.net/10962/d1004828 , Computer networks -- Management , Streaming video , Mass media -- Technological innovations
- Description: Distributed media streaming has been driven by the combination of improved media compression techniques and an increase in the availability of bandwidth. This increase has lead to the development of various streaming distribution engines (systems/services), which currently provide the majority of the streaming media available throughout the Internet. This study aimed to analyse a range of existing commercial and open-source streaming media distribution engines, and classify them in such a way as to define a Common Analysis Framework for Simulated Streaming-Video Networks (CAFSS-Net). This common framework was used as the basis for a simulation tool intended to aid in the development and deployment of streaming media networks and predict the performance impacts of both network configuration changes, video features (scene complexity, resolution) and general scaling. CAFSS-Net consists of six components: the server, the client(s), the network simulator, the video publishing tools, the videos and the evaluation tool-set. Test scenarios are presented consisting of different network configurations, scales and external traffic specifications. From these test scenarios, results were obtained to determine interesting observations attained and to provide an overview of the different test specications for this study. From these results, an analysis of the system was performed, yielding relationships between the videos, the different bandwidths, the different measurement tools and the different components of CAFSS-Net. Based on the analysis of the results, the implications for CAFSS-Net highlighted different achievements and proposals for future work for the different components. CAFSS-Net was able to successfully integrate all of its components to evaluate the different streaming scenarios. The streaming server, client and video components accomplished their objectives. It is noted that although the video publishing tool was able to provide the necessary compression/decompression services, proposals for the implementation of alternative compression/decompression schemes could serve as a suitable extension. The network simulator and evaluation tool-set components were also successful, but future tests (particularly in low bandwidth scenarios) are suggested in order to further improve the accuracy of the framework as a whole. CAFSS-Net is especially successful with analysing high bandwidth connections with the results being similar to those of the physical network tests.
- Full Text:
- Date Issued: 2009
- Authors: Mulumba, Patrick
- Date: 2009
- Subjects: Computer networks -- Management , Streaming video , Mass media -- Technological innovations
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4590 , http://hdl.handle.net/10962/d1004828 , Computer networks -- Management , Streaming video , Mass media -- Technological innovations
- Description: Distributed media streaming has been driven by the combination of improved media compression techniques and an increase in the availability of bandwidth. This increase has lead to the development of various streaming distribution engines (systems/services), which currently provide the majority of the streaming media available throughout the Internet. This study aimed to analyse a range of existing commercial and open-source streaming media distribution engines, and classify them in such a way as to define a Common Analysis Framework for Simulated Streaming-Video Networks (CAFSS-Net). This common framework was used as the basis for a simulation tool intended to aid in the development and deployment of streaming media networks and predict the performance impacts of both network configuration changes, video features (scene complexity, resolution) and general scaling. CAFSS-Net consists of six components: the server, the client(s), the network simulator, the video publishing tools, the videos and the evaluation tool-set. Test scenarios are presented consisting of different network configurations, scales and external traffic specifications. From these test scenarios, results were obtained to determine interesting observations attained and to provide an overview of the different test specications for this study. From these results, an analysis of the system was performed, yielding relationships between the videos, the different bandwidths, the different measurement tools and the different components of CAFSS-Net. Based on the analysis of the results, the implications for CAFSS-Net highlighted different achievements and proposals for future work for the different components. CAFSS-Net was able to successfully integrate all of its components to evaluate the different streaming scenarios. The streaming server, client and video components accomplished their objectives. It is noted that although the video publishing tool was able to provide the necessary compression/decompression services, proposals for the implementation of alternative compression/decompression schemes could serve as a suitable extension. The network simulator and evaluation tool-set components were also successful, but future tests (particularly in low bandwidth scenarios) are suggested in order to further improve the accuracy of the framework as a whole. CAFSS-Net is especially successful with analysing high bandwidth connections with the results being similar to those of the physical network tests.
- Full Text:
- Date Issued: 2009
A common law view of "carrying on a trade"
- Authors: Mkonza, Qhinga Aidan
- Date: 2018
- Subjects: Business , Common law -- South Africa , Income tax -- South Africa , Agriculture -- Taxation -- South Africa , Property tax -- South Africa , Moneylenders -- Taxation -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/60888 , vital:27883
- Description: The term “trade” is defined in very wide terms in the Income Tax Act and includes a “business” and a “venture”. For a taxpayer to claim certain deductions in arriving at taxable income, the taxpayer must be carrying on a trade. The expression “carrying on a trade” is not defined in the Income Tax Act. Whether or not a taxpayer is carrying on a trade is a matter of fact. Case law has established certain principles and tests to be applied in determining whether a taxpayer is carrying on a trade. The goal of the thesis was to determine to what extent an activity can be considered as carrying on a trade. This research focused on the letting of property, money-lending, or farming operations in relation to carrying on a trade or business or engaging in a venture. The thesis also discussed at what stage a taxpayer ceases to carry on a trade and what the tax consequences are of ceasing to trade. An interpretative research approach was used in the research as it sought to understand and describe. No interviews conducted for this research and the data used for the research are publicly available. It was established that “carrying on a trade”, including a business, requires an active step taken by the taxpayer to trade. It involves regularity of buying and selling or rendering of services. The intention to trade is important but it is a subjective matter and cannot be persuasive in determining whether a taxpayer is carrying on a trade; objective factors are also considered. If the stated intention to trade matches the actions of the taxpayer, the taxpayer will be considered to be carrying on a trade. In determining whether a taxpayer is carrying on a trade each case must be considered with its own merits.
- Full Text:
- Date Issued: 2018
- Authors: Mkonza, Qhinga Aidan
- Date: 2018
- Subjects: Business , Common law -- South Africa , Income tax -- South Africa , Agriculture -- Taxation -- South Africa , Property tax -- South Africa , Moneylenders -- Taxation -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/60888 , vital:27883
- Description: The term “trade” is defined in very wide terms in the Income Tax Act and includes a “business” and a “venture”. For a taxpayer to claim certain deductions in arriving at taxable income, the taxpayer must be carrying on a trade. The expression “carrying on a trade” is not defined in the Income Tax Act. Whether or not a taxpayer is carrying on a trade is a matter of fact. Case law has established certain principles and tests to be applied in determining whether a taxpayer is carrying on a trade. The goal of the thesis was to determine to what extent an activity can be considered as carrying on a trade. This research focused on the letting of property, money-lending, or farming operations in relation to carrying on a trade or business or engaging in a venture. The thesis also discussed at what stage a taxpayer ceases to carry on a trade and what the tax consequences are of ceasing to trade. An interpretative research approach was used in the research as it sought to understand and describe. No interviews conducted for this research and the data used for the research are publicly available. It was established that “carrying on a trade”, including a business, requires an active step taken by the taxpayer to trade. It involves regularity of buying and selling or rendering of services. The intention to trade is important but it is a subjective matter and cannot be persuasive in determining whether a taxpayer is carrying on a trade; objective factors are also considered. If the stated intention to trade matches the actions of the taxpayer, the taxpayer will be considered to be carrying on a trade. In determining whether a taxpayer is carrying on a trade each case must be considered with its own merits.
- Full Text:
- Date Issued: 2018
A community partner’s perceptions of a service-learning partnership
- Authors: Queripel, Kathryn
- Date: 2017
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/6978 , vital:21206
- Description: Literature has highlighted the importance of university-community partnerships in servicelearning (SL) as a vehicle for conducting a mutually beneficial service-learning programme (Dorado & Giles, 2004). This research aimed to investigate factors influencing a SL partnership through the insights of a particular community partner. Based on a case study of a rural school in the Eastern Cape, three community partners perceptions were obtained through in-depth semi-structured interviews. Thereafter, thematic analysis was used to analyse the data using Braun and Clarke’s (2006) six phase guide. Three main theme’s emerged from the data that shed light to the key issues shaping community partners perceptions. These were centred on the effects of apartheid including resources, geographic location, and level of commitment from the university. The findings of this research brought forward the importance of awareness of context, responding to the context and commitment displayed in the partnership. This research further highlights the need for community partner’s perspective in literature.
- Full Text:
- Date Issued: 2017
- Authors: Queripel, Kathryn
- Date: 2017
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/6978 , vital:21206
- Description: Literature has highlighted the importance of university-community partnerships in servicelearning (SL) as a vehicle for conducting a mutually beneficial service-learning programme (Dorado & Giles, 2004). This research aimed to investigate factors influencing a SL partnership through the insights of a particular community partner. Based on a case study of a rural school in the Eastern Cape, three community partners perceptions were obtained through in-depth semi-structured interviews. Thereafter, thematic analysis was used to analyse the data using Braun and Clarke’s (2006) six phase guide. Three main theme’s emerged from the data that shed light to the key issues shaping community partners perceptions. These were centred on the effects of apartheid including resources, geographic location, and level of commitment from the university. The findings of this research brought forward the importance of awareness of context, responding to the context and commitment displayed in the partnership. This research further highlights the need for community partner’s perspective in literature.
- Full Text:
- Date Issued: 2017
A community–wide trophic structure analysis in intertidal ecosystems on the south coast of South Africa
- Authors: Gusha, Molline Natanah C
- Date: 2018
- Subjects: Food chains (Ecology) , Coastal ecology -- South Africa , Intertidal ecology -- South Africa , Marine animals -- Climatic factors -- South Africa , Marine animals -- Food -- South Africa , Marine animals -- Habitat -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63312 , vital:28392
- Description: Coastal ecosystems are more than microhabitats for marine species. Acting as atmospheric carbon filters, species in coastal environments are directly and/or indirectly associated with transferring organic carbon to species at higher trophic levels. However, the progressing change in global climatic conditions has created the need to assess the consequences of the shifting conditions on both direct and indirect interactions of physical and biological parameters at species and/or community levels. From these perturbations, the effects of biotic homogenization on ecosystem functioning and resilience can also be realised. Herein, I discuss the effects of temperature, nutrients, biotic interactions and habitat characteristics on community dynamics within intertidal rock pool systems on the south coast of South Africa using complementary qualitative and quantitative analytical methods. Seasonality had a significant impact on rock pool species with changes in composition and higher richness in winter than summer. The first two axes of the Canonical Correspondence Analysis (CCA) of the plant and animal communities each explained ~20% of the relationship between physico-chemical parameters and biological variables. The CCA highlighted that seasonal shifts in chlorophyll-a, conductivity, salinity, water depth, surface area and substratum type indirectly influenced species composition. For example, pools with heterogenous substratum comprising a mixture of sand and rock exhibited higher species diversity than homogenously bedded pools. Furthermore, a Bayesian analysis of community structure based on stable isotope ratios was used to assess how trophic pathways of carbon and nitrogen elements reflected community composition and richness. Isotopic biplots showed an increase in food web size, food chain length and the trophic positions of fish and some gastropods in winter compared to summer. There was greater dietary overlap among species in larger pools. In addition, while isotopic nearest neighbour distance and species evenness also showed a positive increase with pool size in summer, the same metrics were almost constant across all pool sizes in winter. These changes in food web packing and species evenness suggest seasonal preferences or migration of species in summer from small pools to larger pools with stable physico-chemical parameters. Furthermore, the presence of fish was seen to promote trophic diversity within some pools. The results from laboratory microcosm grazing experiments demonstrated significant direct and indirect effects of temperature and nutrients within plankton communities. Copepod grazing had an indirect positive influence on phytoplankton biomass and size structure while the interactive effects of temperature and nutrients had contrasting effects on both phytoplankton communities and copepod biomass. Shifts in water chemistry and nutrient treatments were also observed in the presence of copepods. Phosphate addition had a recognisable impact on plankton communities. The presented synthesis of the literature mainly highlighted that positive effects at one trophic level do not always positively cascade into the next trophic level which is evidence of complex interactive biotic, habitat and water chemistry effects within these intertidal ecosystems. Thus, to further understand cascading effects or community structure functioning in general, there may be a need to incorporate and understand species functional traits and how they contribute to trophic diversity, community restructuring and functioning in coastal habitats.
- Full Text:
- Date Issued: 2018
- Authors: Gusha, Molline Natanah C
- Date: 2018
- Subjects: Food chains (Ecology) , Coastal ecology -- South Africa , Intertidal ecology -- South Africa , Marine animals -- Climatic factors -- South Africa , Marine animals -- Food -- South Africa , Marine animals -- Habitat -- South Africa
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/63312 , vital:28392
- Description: Coastal ecosystems are more than microhabitats for marine species. Acting as atmospheric carbon filters, species in coastal environments are directly and/or indirectly associated with transferring organic carbon to species at higher trophic levels. However, the progressing change in global climatic conditions has created the need to assess the consequences of the shifting conditions on both direct and indirect interactions of physical and biological parameters at species and/or community levels. From these perturbations, the effects of biotic homogenization on ecosystem functioning and resilience can also be realised. Herein, I discuss the effects of temperature, nutrients, biotic interactions and habitat characteristics on community dynamics within intertidal rock pool systems on the south coast of South Africa using complementary qualitative and quantitative analytical methods. Seasonality had a significant impact on rock pool species with changes in composition and higher richness in winter than summer. The first two axes of the Canonical Correspondence Analysis (CCA) of the plant and animal communities each explained ~20% of the relationship between physico-chemical parameters and biological variables. The CCA highlighted that seasonal shifts in chlorophyll-a, conductivity, salinity, water depth, surface area and substratum type indirectly influenced species composition. For example, pools with heterogenous substratum comprising a mixture of sand and rock exhibited higher species diversity than homogenously bedded pools. Furthermore, a Bayesian analysis of community structure based on stable isotope ratios was used to assess how trophic pathways of carbon and nitrogen elements reflected community composition and richness. Isotopic biplots showed an increase in food web size, food chain length and the trophic positions of fish and some gastropods in winter compared to summer. There was greater dietary overlap among species in larger pools. In addition, while isotopic nearest neighbour distance and species evenness also showed a positive increase with pool size in summer, the same metrics were almost constant across all pool sizes in winter. These changes in food web packing and species evenness suggest seasonal preferences or migration of species in summer from small pools to larger pools with stable physico-chemical parameters. Furthermore, the presence of fish was seen to promote trophic diversity within some pools. The results from laboratory microcosm grazing experiments demonstrated significant direct and indirect effects of temperature and nutrients within plankton communities. Copepod grazing had an indirect positive influence on phytoplankton biomass and size structure while the interactive effects of temperature and nutrients had contrasting effects on both phytoplankton communities and copepod biomass. Shifts in water chemistry and nutrient treatments were also observed in the presence of copepods. Phosphate addition had a recognisable impact on plankton communities. The presented synthesis of the literature mainly highlighted that positive effects at one trophic level do not always positively cascade into the next trophic level which is evidence of complex interactive biotic, habitat and water chemistry effects within these intertidal ecosystems. Thus, to further understand cascading effects or community structure functioning in general, there may be a need to incorporate and understand species functional traits and how they contribute to trophic diversity, community restructuring and functioning in coastal habitats.
- Full Text:
- Date Issued: 2018
A comparative analysis of derivative regulation following the global financial crisis : an emerging markets perspective
- Authors: Mpala, Nqobile Natasha
- Date: 2015
- Subjects: Derivative securities , Global Financial Crisis, 2008-2009 , Capital market -- Developing countries , Derivative securities -- Developing countries , International economic relations
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1121 , http://hdl.handle.net/10962/d1018660
- Description: The international financial environment has become riskier due to the recent developments in product offerings and failure of regulation to keep abreast with these changes. The Global Financial Crisis exposed inadequacies of regulation, thus consensus on the need for comprehensive and uniform regulation was made by G-20 member states. Imposing exchange trading, clearing, reporting and capital requirements on the derivatives market are some of the ways of dealing with the problems caused by lax regulatory oversight. In this study, through the comparative analysis of derivatives regulation in South Africa, Brazil, India and Turkey, it was established that emerging countries are taking active steps to implement the G-20 agreement. Uniformity in the core rules was noted, with differences in the supportive legislation. Country specific rules which support the macroeconomic factors that are faced by these countries and the infrastructure available for regulatory execution are used amongst countries. The study concluded that current regulation in emerging countries is accommodative and regulatory differences are in line with economic factors in each country.
- Full Text:
- Date Issued: 2015
- Authors: Mpala, Nqobile Natasha
- Date: 2015
- Subjects: Derivative securities , Global Financial Crisis, 2008-2009 , Capital market -- Developing countries , Derivative securities -- Developing countries , International economic relations
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1121 , http://hdl.handle.net/10962/d1018660
- Description: The international financial environment has become riskier due to the recent developments in product offerings and failure of regulation to keep abreast with these changes. The Global Financial Crisis exposed inadequacies of regulation, thus consensus on the need for comprehensive and uniform regulation was made by G-20 member states. Imposing exchange trading, clearing, reporting and capital requirements on the derivatives market are some of the ways of dealing with the problems caused by lax regulatory oversight. In this study, through the comparative analysis of derivatives regulation in South Africa, Brazil, India and Turkey, it was established that emerging countries are taking active steps to implement the G-20 agreement. Uniformity in the core rules was noted, with differences in the supportive legislation. Country specific rules which support the macroeconomic factors that are faced by these countries and the infrastructure available for regulatory execution are used amongst countries. The study concluded that current regulation in emerging countries is accommodative and regulatory differences are in line with economic factors in each country.
- Full Text:
- Date Issued: 2015
A comparative analysis of environmental policies of South African universities
- Authors: Gyan, Cecilia Adwoa
- Date: 2006
- Subjects: Environmental education -- South Africa , Sustainable development -- Study and teaching , Education, Higher -- South Africa , Universities and colleges -- Environmental aspects , Environmental policy -- South Africa , Campus planning -- Environmental aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4773 , http://hdl.handle.net/10962/d1008067 , Environmental education -- South Africa , Sustainable development -- Study and teaching , Education, Higher -- South Africa , Universities and colleges -- Environmental aspects , Environmental policy -- South Africa , Campus planning -- Environmental aspects -- South Africa
- Description: There has been ongoing global concern on environmental issues and which is supposed to have moved down into smaller institutions and areas through local agenda 2l. Environmental issues are associated not only with care for the environment but also sustainable development. Various universities are beginning to strive for sustainable development and care for the environment. Some universities are therefore integrating care for the environment in their curricula and in their daily operations on campus. The greening of higher educational institutions as models is important as they are the seat for research and training of undergraduates who will become future leaders and policymakers and caretakers of the environment. It is therefore important for undergraduates to be exposed to greening processes in operations, research and curricula whilst still on campus. This study examines the process of formulating a policy and applies that to forming an environmental policy. The study involved a comparative analysis of environmental policies of various tertiary educational institutions from different countries. The study focused on how many universities in South Africa have environmental policies and how the universities which have environmental policies went about their formulation process. The study further examines the duration of the formulation process and the constraints encountered by universities. The study then reviews strategies on how the environmental policy is being implemented and how effective the implementation process is practically and the constraints these institutions face. The findings of the study reveal that few universities ill South Africa have an environmental policy. The universities are making efforts in their implementation process however, not all the principles found in the policies are being implemented effectively as there are no environmental management systems in place and there are no measurable objectives and targets set for proper evaluation of the success or failure of the policy.
- Full Text:
- Date Issued: 2006
- Authors: Gyan, Cecilia Adwoa
- Date: 2006
- Subjects: Environmental education -- South Africa , Sustainable development -- Study and teaching , Education, Higher -- South Africa , Universities and colleges -- Environmental aspects , Environmental policy -- South Africa , Campus planning -- Environmental aspects -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4773 , http://hdl.handle.net/10962/d1008067 , Environmental education -- South Africa , Sustainable development -- Study and teaching , Education, Higher -- South Africa , Universities and colleges -- Environmental aspects , Environmental policy -- South Africa , Campus planning -- Environmental aspects -- South Africa
- Description: There has been ongoing global concern on environmental issues and which is supposed to have moved down into smaller institutions and areas through local agenda 2l. Environmental issues are associated not only with care for the environment but also sustainable development. Various universities are beginning to strive for sustainable development and care for the environment. Some universities are therefore integrating care for the environment in their curricula and in their daily operations on campus. The greening of higher educational institutions as models is important as they are the seat for research and training of undergraduates who will become future leaders and policymakers and caretakers of the environment. It is therefore important for undergraduates to be exposed to greening processes in operations, research and curricula whilst still on campus. This study examines the process of formulating a policy and applies that to forming an environmental policy. The study involved a comparative analysis of environmental policies of various tertiary educational institutions from different countries. The study focused on how many universities in South Africa have environmental policies and how the universities which have environmental policies went about their formulation process. The study further examines the duration of the formulation process and the constraints encountered by universities. The study then reviews strategies on how the environmental policy is being implemented and how effective the implementation process is practically and the constraints these institutions face. The findings of the study reveal that few universities ill South Africa have an environmental policy. The universities are making efforts in their implementation process however, not all the principles found in the policies are being implemented effectively as there are no environmental management systems in place and there are no measurable objectives and targets set for proper evaluation of the success or failure of the policy.
- Full Text:
- Date Issued: 2006
A comparative analysis of Java and .NET mobile development environments for supporting mobile services
- Authors: Zhao, Xiaogeng
- Date: 2003 , 2013-05-23
- Subjects: Microsoft .NET , Java (Computer program language) , Mobile computing , Wireless communication systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4578 , http://hdl.handle.net/10962/d1003064 , Microsoft .NET , Java (Computer program language) , Mobile computing , Wireless communication systems
- Description: With the rapid development of wireless technologies, traditional mobile devices, such as pagers and cellular phones, have evolved from a purely communications and messaging-oriented medium to one that supports mobile data communication in general and acts as an application platform. As shown in a recent survey conducted by MDA, easy access to the present-day wireless Internet has resulted in mobile devices gaining more and more attention and popularity. The growth of and demand for mobile Web applications is expected to increase rapidly in the near future, as a range of software companies and mobile device manufacturers release increasingly accessible tools for creating mobile Web application and services. From a variety of possible development environments of this kind, the author has selected and examined two leading contenders, the J2ME and the Microsoft .NET mobile Web application development environments. This document reports the product life cycle of pilot mobile web applications, designed and implemented in each host environment in tum. A feature-by-feature investigation and comparison of the J2ME and .NET environments was carried out, covering the range of issues necessary for a complete mobile Web application development life cycle. The resulting analysis addresses features and efficiencies of the application development environment and the target deployment environment, the degree to which the resultant services are compatible on a variety of platforms, and the ease with which applications can be designed to be extensible. The thesis offers an objective evaluation of the J2ME and the .NET mobile development environments, which highlights their strengths and weaknesses, and suggests guidelines for designing, creating, and deploying high quality mobile Web applications. The research uncovers no clear winner across all categories assessed. J2ME currently favours situations in which bandwidth is limited and client side processing power is relatively sufficient, it exerts the processing power of mobile devices over distributed network environments. .NET requires a less constrained network throughput, but performs adequately on clients with more limited processing power, supports a more diverse target platform range, and offers a more efficient, in terms of development time, development environment. Both technologies are likely to receive significant user support for some time. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2003
- Authors: Zhao, Xiaogeng
- Date: 2003 , 2013-05-23
- Subjects: Microsoft .NET , Java (Computer program language) , Mobile computing , Wireless communication systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4578 , http://hdl.handle.net/10962/d1003064 , Microsoft .NET , Java (Computer program language) , Mobile computing , Wireless communication systems
- Description: With the rapid development of wireless technologies, traditional mobile devices, such as pagers and cellular phones, have evolved from a purely communications and messaging-oriented medium to one that supports mobile data communication in general and acts as an application platform. As shown in a recent survey conducted by MDA, easy access to the present-day wireless Internet has resulted in mobile devices gaining more and more attention and popularity. The growth of and demand for mobile Web applications is expected to increase rapidly in the near future, as a range of software companies and mobile device manufacturers release increasingly accessible tools for creating mobile Web application and services. From a variety of possible development environments of this kind, the author has selected and examined two leading contenders, the J2ME and the Microsoft .NET mobile Web application development environments. This document reports the product life cycle of pilot mobile web applications, designed and implemented in each host environment in tum. A feature-by-feature investigation and comparison of the J2ME and .NET environments was carried out, covering the range of issues necessary for a complete mobile Web application development life cycle. The resulting analysis addresses features and efficiencies of the application development environment and the target deployment environment, the degree to which the resultant services are compatible on a variety of platforms, and the ease with which applications can be designed to be extensible. The thesis offers an objective evaluation of the J2ME and the .NET mobile development environments, which highlights their strengths and weaknesses, and suggests guidelines for designing, creating, and deploying high quality mobile Web applications. The research uncovers no clear winner across all categories assessed. J2ME currently favours situations in which bandwidth is limited and client side processing power is relatively sufficient, it exerts the processing power of mobile devices over distributed network environments. .NET requires a less constrained network throughput, but performs adequately on clients with more limited processing power, supports a more diverse target platform range, and offers a more efficient, in terms of development time, development environment. Both technologies are likely to receive significant user support for some time. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2003
A comparative analysis of social media brand image of insurance companies in South Africa: a longitudinal study
- Authors: Gudu, Daniel
- Date: 2020
- Subjects: Social media -- South Africa , Internet marketing -- South Africa , Chernoff faces , Ínsurance companies -- South Africa -- Marketing , Insurance companies -- South Africa -- Case studies , Multivariate analysis -- Graphic methods
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/144277 , vital:38327
- Description: Social media is changing the way business is conducted. Almost five billion videos are watched on YouTube every single day. Social media has an extensive worldwide presence. Out of the total global population of over 7,5 billion people, over 4 billion are internet users. Of these, over 3 billion are active on social media. Social media is very influential in today's decision-making processes. Businesses must integrate social media into their strategies. The purpose of this research was to investigate the use of a novel method, Chernoff Faces, to assess and compare the social media brand images of six insurance companies in South Africa based on social conversation measurement. The intention of research was towards observing existing situations at hand and pointing out the game changers that can provide the industry with a new leap. Social media are multidimensional and understanding them requires tracking different measures simultaneously. Integrating social media into a communication strategy leads to a problem in finding the best way to portray and communicate multivariate data. It is essential to find the best way to represent and transmit the data so that marketing executives can quickly and easily monitor changes in brand images. Previous studies have successfully proved the possibility of using this method to gauge a "snapshot in time." This study took the concept further by closely monitoring the results for a set of brands over a period to account for the dynamic nature of social media. Accordingly, the study was a longitudinal study of 30 days. Data on the insurance companies was collected from Social Mention, a social media search and analysis platform that aggregates user-generated content into a single stream of information. A tool in the statistical software Stata, Chernoff's faces, was used to analyse the results by generating facial expressions to the metrics associated with the social mentions of each of the insurance companies. The resulting facial expressions were then analysed to recognise the more favourable and stable brands and those that need appropriate risk management. Managing Social Media is challenging as managers must always keep it as positive as possible. Brand managers, therefore, need a better tool to gauge the mood in social media conversations due to the fast-changing nature of social media and the importance of social media to business especially insurance.
- Full Text:
- Date Issued: 2020
- Authors: Gudu, Daniel
- Date: 2020
- Subjects: Social media -- South Africa , Internet marketing -- South Africa , Chernoff faces , Ínsurance companies -- South Africa -- Marketing , Insurance companies -- South Africa -- Case studies , Multivariate analysis -- Graphic methods
- Language: English
- Type: text , Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10962/144277 , vital:38327
- Description: Social media is changing the way business is conducted. Almost five billion videos are watched on YouTube every single day. Social media has an extensive worldwide presence. Out of the total global population of over 7,5 billion people, over 4 billion are internet users. Of these, over 3 billion are active on social media. Social media is very influential in today's decision-making processes. Businesses must integrate social media into their strategies. The purpose of this research was to investigate the use of a novel method, Chernoff Faces, to assess and compare the social media brand images of six insurance companies in South Africa based on social conversation measurement. The intention of research was towards observing existing situations at hand and pointing out the game changers that can provide the industry with a new leap. Social media are multidimensional and understanding them requires tracking different measures simultaneously. Integrating social media into a communication strategy leads to a problem in finding the best way to portray and communicate multivariate data. It is essential to find the best way to represent and transmit the data so that marketing executives can quickly and easily monitor changes in brand images. Previous studies have successfully proved the possibility of using this method to gauge a "snapshot in time." This study took the concept further by closely monitoring the results for a set of brands over a period to account for the dynamic nature of social media. Accordingly, the study was a longitudinal study of 30 days. Data on the insurance companies was collected from Social Mention, a social media search and analysis platform that aggregates user-generated content into a single stream of information. A tool in the statistical software Stata, Chernoff's faces, was used to analyse the results by generating facial expressions to the metrics associated with the social mentions of each of the insurance companies. The resulting facial expressions were then analysed to recognise the more favourable and stable brands and those that need appropriate risk management. Managing Social Media is challenging as managers must always keep it as positive as possible. Brand managers, therefore, need a better tool to gauge the mood in social media conversations due to the fast-changing nature of social media and the importance of social media to business especially insurance.
- Full Text:
- Date Issued: 2020
A comparative analysis of the divisia index and the simple sum monetary aggregates for South Africa
- Authors: Moyo, Solomon Simbarashe
- Date: 2009
- Subjects: Monetary policy -- South Africa , Money supply -- South Africa , Inflation finance -- South Africa , Index numbers (Economics)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:945 , http://hdl.handle.net/10962/d1002679 , Monetary policy -- South Africa , Money supply -- South Africa , Inflation finance -- South Africa , Index numbers (Economics)
- Description: The effectiveness of monetary policy in achieving its macroeconomic objectives such as price stability and economic growth depend on the monetary policy tools that are implemented by the Central Bank. Monetary aggregates are one of the tools that have been used as indicators of economic activity and as intermediate targets to achieve these economic objectives. Until recently, monetary aggregates have been questioned and criticised on their usefulness in monetary policy. This has been attributed to the economic, financial and technological developments that have distorted the relationship between monetary aggregates and major macroeconomic variables. This study investigates the relevance of monetary aggregation by comparing the traditional simple sum and Divisia index monetary aggregates which was constructed for the first time for South Africa using the Tornquist-Theil method. The Polynomial Distributed Lag model is employed to compare the performance of these monetary aggregates using their relationship with inflation and manufacturing index. Furthermore, the aggregates are compared in terms of their controllability and information content. Overall, the study found a very strong relationship between inflation and all the monetary aggregates. However, more specifically the results suggested that the Divisia indices are superior to the simple sum in terms of predicting inflation. The evidence further suggests that the Divisia aggregates provide higher information about inflation than the simple sum aggregates. Regarding the controllability of the monetary aggregates, the findings suggest that the monetary authorities can hardly control the monetary aggregates using monetary base. Finally, the relationship between manufacturing index and all the monetary aggregates was very weak.
- Full Text:
- Date Issued: 2009
- Authors: Moyo, Solomon Simbarashe
- Date: 2009
- Subjects: Monetary policy -- South Africa , Money supply -- South Africa , Inflation finance -- South Africa , Index numbers (Economics)
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:945 , http://hdl.handle.net/10962/d1002679 , Monetary policy -- South Africa , Money supply -- South Africa , Inflation finance -- South Africa , Index numbers (Economics)
- Description: The effectiveness of monetary policy in achieving its macroeconomic objectives such as price stability and economic growth depend on the monetary policy tools that are implemented by the Central Bank. Monetary aggregates are one of the tools that have been used as indicators of economic activity and as intermediate targets to achieve these economic objectives. Until recently, monetary aggregates have been questioned and criticised on their usefulness in monetary policy. This has been attributed to the economic, financial and technological developments that have distorted the relationship between monetary aggregates and major macroeconomic variables. This study investigates the relevance of monetary aggregation by comparing the traditional simple sum and Divisia index monetary aggregates which was constructed for the first time for South Africa using the Tornquist-Theil method. The Polynomial Distributed Lag model is employed to compare the performance of these monetary aggregates using their relationship with inflation and manufacturing index. Furthermore, the aggregates are compared in terms of their controllability and information content. Overall, the study found a very strong relationship between inflation and all the monetary aggregates. However, more specifically the results suggested that the Divisia indices are superior to the simple sum in terms of predicting inflation. The evidence further suggests that the Divisia aggregates provide higher information about inflation than the simple sum aggregates. Regarding the controllability of the monetary aggregates, the findings suggest that the monetary authorities can hardly control the monetary aggregates using monetary base. Finally, the relationship between manufacturing index and all the monetary aggregates was very weak.
- Full Text:
- Date Issued: 2009
A comparative analysis of the intermediary systems in South Africa, Namibia, Zimbabwe and Ethiopia
- Authors: Wilkerson, Tendai Marowa
- Date: 2011
- Subjects: Juvenile courts -- South Africa , Juvenile courts -- Namibia , Juveline courts -- Zimbabwe , Juvenile courts -- Ethiopia , Children -- Legal status, laws, etc. -- South Africa , Children -- Legal status, laws, etc. -- Namibia , Children -- Legal status, laws, etc. -- Zimbabwe , Children -- Legal status, laws, etc. -- Ethiopia , Child witnesses -- South Africa , Child witnesses -- Namibia , Child witnesses -- Zimbabwe , Child witnesses -- Ethiopia , Mediation -- Law and legislation -- South Africa , Mediation -- Law and legislation -- Namibia , Mediation -- Law and legislation -- Zimbabwe , Mediation -- Law and legislation -- Ethiopia , Children's rights -- South Africa , Children's rights -- Namibia , Children's rights -- Zimbabwe , Children's rights -- Ethiopia
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3698 , http://hdl.handle.net/10962/d1003213 , Juvenile courts -- South Africa , Juvenile courts -- Namibia , Juveline courts -- Zimbabwe , Juvenile courts -- Ethiopia , Children -- Legal status, laws, etc. -- South Africa , Children -- Legal status, laws, etc. -- Namibia , Children -- Legal status, laws, etc. -- Zimbabwe , Children -- Legal status, laws, etc. -- Ethiopia , Child witnesses -- South Africa , Child witnesses -- Namibia , Child witnesses -- Zimbabwe , Child witnesses -- Ethiopia , Mediation -- Law and legislation -- South Africa , Mediation -- Law and legislation -- Namibia , Mediation -- Law and legislation -- Zimbabwe , Mediation -- Law and legislation -- Ethiopia , Children's rights -- South Africa , Children's rights -- Namibia , Children's rights -- Zimbabwe , Children's rights -- Ethiopia
- Description: Prior to 1990, very few countries in the world offered special protection to child witnesses interfacing with the justice system. There were no legal provisions permitting testimonial accommodations for children in court. The courtroom experience was significantly traumatic for the children. With the international focus shifting from protecting and upholding the rights of the accused in the courtroom towards a more victim-centred approach, various international and regional instruments have strongly dvocated that children deserve special protection because of their vulnerability. In order for the courts to be able to elicit accurate evidence from the child without further traumatizing the child, research has shown that the child needs assistance. An intermediary may be defined as a person who facilitates communication between the child and the courtroom in a manner that takes into account the child‟s cognitive and developmental limitations. The thesis was prompted by the need to make a contribution to the currently limited body of literature on the intermediary systems in South Africa, Namibia, Zimbabwe and Ethiopia by investigating how the systems can be improved and sustained in a way that helps to protect the child witness in court. Despite the problems the South African courts have had in identifying the appropriate interpretation of its intermediary legislation, the country emerges as a clear leader for the steps it took by creating a positive legal framework within which child protection issues are addressed and introducing the concept of the intermediary. This concept proved to be an inspiration to its neighbours, Namibia and Zimbabwe. The influence of the South African intermediary legislation is evident in the Namibian and Zimbabwean legislation. Although Namibian legislators have drafted laws that permit intermediary assistance in court, there are as yet no intermediaries appointed. In Ethiopia, although there is no discernible intermediary legislation, the country has managed to establish an intermediary system. As a result of the analysis conducted, it is evident that the efficacy of the intermediary system is dependent on the presence of an enabling legislation, its clarity and ease of interpretation, the sensitisation of court role players on child vulnerabilities, the significance of intermediary assistance, and finally a government's commitment towards the implementation process.
- Full Text:
- Date Issued: 2011
- Authors: Wilkerson, Tendai Marowa
- Date: 2011
- Subjects: Juvenile courts -- South Africa , Juvenile courts -- Namibia , Juveline courts -- Zimbabwe , Juvenile courts -- Ethiopia , Children -- Legal status, laws, etc. -- South Africa , Children -- Legal status, laws, etc. -- Namibia , Children -- Legal status, laws, etc. -- Zimbabwe , Children -- Legal status, laws, etc. -- Ethiopia , Child witnesses -- South Africa , Child witnesses -- Namibia , Child witnesses -- Zimbabwe , Child witnesses -- Ethiopia , Mediation -- Law and legislation -- South Africa , Mediation -- Law and legislation -- Namibia , Mediation -- Law and legislation -- Zimbabwe , Mediation -- Law and legislation -- Ethiopia , Children's rights -- South Africa , Children's rights -- Namibia , Children's rights -- Zimbabwe , Children's rights -- Ethiopia
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3698 , http://hdl.handle.net/10962/d1003213 , Juvenile courts -- South Africa , Juvenile courts -- Namibia , Juveline courts -- Zimbabwe , Juvenile courts -- Ethiopia , Children -- Legal status, laws, etc. -- South Africa , Children -- Legal status, laws, etc. -- Namibia , Children -- Legal status, laws, etc. -- Zimbabwe , Children -- Legal status, laws, etc. -- Ethiopia , Child witnesses -- South Africa , Child witnesses -- Namibia , Child witnesses -- Zimbabwe , Child witnesses -- Ethiopia , Mediation -- Law and legislation -- South Africa , Mediation -- Law and legislation -- Namibia , Mediation -- Law and legislation -- Zimbabwe , Mediation -- Law and legislation -- Ethiopia , Children's rights -- South Africa , Children's rights -- Namibia , Children's rights -- Zimbabwe , Children's rights -- Ethiopia
- Description: Prior to 1990, very few countries in the world offered special protection to child witnesses interfacing with the justice system. There were no legal provisions permitting testimonial accommodations for children in court. The courtroom experience was significantly traumatic for the children. With the international focus shifting from protecting and upholding the rights of the accused in the courtroom towards a more victim-centred approach, various international and regional instruments have strongly dvocated that children deserve special protection because of their vulnerability. In order for the courts to be able to elicit accurate evidence from the child without further traumatizing the child, research has shown that the child needs assistance. An intermediary may be defined as a person who facilitates communication between the child and the courtroom in a manner that takes into account the child‟s cognitive and developmental limitations. The thesis was prompted by the need to make a contribution to the currently limited body of literature on the intermediary systems in South Africa, Namibia, Zimbabwe and Ethiopia by investigating how the systems can be improved and sustained in a way that helps to protect the child witness in court. Despite the problems the South African courts have had in identifying the appropriate interpretation of its intermediary legislation, the country emerges as a clear leader for the steps it took by creating a positive legal framework within which child protection issues are addressed and introducing the concept of the intermediary. This concept proved to be an inspiration to its neighbours, Namibia and Zimbabwe. The influence of the South African intermediary legislation is evident in the Namibian and Zimbabwean legislation. Although Namibian legislators have drafted laws that permit intermediary assistance in court, there are as yet no intermediaries appointed. In Ethiopia, although there is no discernible intermediary legislation, the country has managed to establish an intermediary system. As a result of the analysis conducted, it is evident that the efficacy of the intermediary system is dependent on the presence of an enabling legislation, its clarity and ease of interpretation, the sensitisation of court role players on child vulnerabilities, the significance of intermediary assistance, and finally a government's commitment towards the implementation process.
- Full Text:
- Date Issued: 2011
A comparative analysis of the new behaviours and terms introduced in the understatement penalty table in section 223 of the Tax Administration Act
- Authors: Doolan, Kim
- Date: 2017
- Subjects: South Africa. Tax Administration Act, 2011 , Taxation -- South Africa , Taxation -- Law and legislation -- South Africa , Tax administration and procedure -- Law and legislation -- South Africa , Tax penalties -- Law and legislation -- South Africa , Taxpayer compliance -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/5802 , vital:20977
- Description: The Tax Administration Act became effective on the 1 October 2012 and in Chapter 16 introduced the understatement penalty regime which replaced section 76 of the Income Tax Act. The understatement penalty is calculated by applying a percentage in terms of the table included in section 223 of the Tax Administration Act to the shortfall in tax giving rise to the imposition of the penalty. There are five behaviours reflected in the understatement penalty table in section 223, namely, “substantial understatement”, “reasonable care not taken in completing return”, “no reasonable grounds for tax position taken”, “gross negligence” and “intentional tax evasion”. “Substantial understatement” is the only behaviour defined in the Tax Administration Act. Section 222(1) of the Tax Administration Act requires SARS to impose the penalty reflected in the table in the event of an “understatement”, unless the “understatement” results from a “bona fide inadvertent error”. The term “bona fide inadvertent error” is not defined in the Tax Administration Act; neither is the term “obstructive”. The Memorandum on the Objects of the Tax Administration Laws Amendment Bill confirmed that guidance would be developed in this regard for the use of taxpayers and SARS officials. This guidance has not yet been released. Media reports express the view that the lack of definition of the behaviours is problematic for both SARS and taxpayers as the table is new and there is still room for interpretation and understanding of the meaning of each of the behaviours. The primary goal of this study was is to obtain a better understanding of the meaning of the new behaviours and terms introduced in the understatement penalty table. In addressing this main goal, the penalty tables and behaviours in legislation in New Zealand were compared to South Africa’s understatement penalty. The similarities and differences between the understatement penalty imposed in terms of Chapter 16 of the Tax Administration Act and the additional tax previously imposed in terms of section 76 of the Income Tax Act were also discussed to determine whether this would be of assistance in enabling a better understanding of the meaning of the behaviours and terms in section 223. Guidance on the interpretation of the various behaviours and terms was developed and a definition was proposed for the meaning of “bona fide inadvertent error” and “obstructive” to assist in the objective and consistent application of the understatement penalty table in relation to each shortfall identified. The proposed definition for “bona fide inadvertent error” is as follows: “An honest mistake made or simple oversight, which the taxpayer was not aware of, despite taking reasonable care and displaying a prudent attitude while making a genuine attempt to comply with all applicable tax obligations.” The definition for “obstructive” is proposed as: “Deliberately interfering with, causing difficulties (impeding) or delays in, or preventing the progress of a SARS audit or review.”
- Full Text:
- Date Issued: 2017
- Authors: Doolan, Kim
- Date: 2017
- Subjects: South Africa. Tax Administration Act, 2011 , Taxation -- South Africa , Taxation -- Law and legislation -- South Africa , Tax administration and procedure -- Law and legislation -- South Africa , Tax penalties -- Law and legislation -- South Africa , Taxpayer compliance -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/5802 , vital:20977
- Description: The Tax Administration Act became effective on the 1 October 2012 and in Chapter 16 introduced the understatement penalty regime which replaced section 76 of the Income Tax Act. The understatement penalty is calculated by applying a percentage in terms of the table included in section 223 of the Tax Administration Act to the shortfall in tax giving rise to the imposition of the penalty. There are five behaviours reflected in the understatement penalty table in section 223, namely, “substantial understatement”, “reasonable care not taken in completing return”, “no reasonable grounds for tax position taken”, “gross negligence” and “intentional tax evasion”. “Substantial understatement” is the only behaviour defined in the Tax Administration Act. Section 222(1) of the Tax Administration Act requires SARS to impose the penalty reflected in the table in the event of an “understatement”, unless the “understatement” results from a “bona fide inadvertent error”. The term “bona fide inadvertent error” is not defined in the Tax Administration Act; neither is the term “obstructive”. The Memorandum on the Objects of the Tax Administration Laws Amendment Bill confirmed that guidance would be developed in this regard for the use of taxpayers and SARS officials. This guidance has not yet been released. Media reports express the view that the lack of definition of the behaviours is problematic for both SARS and taxpayers as the table is new and there is still room for interpretation and understanding of the meaning of each of the behaviours. The primary goal of this study was is to obtain a better understanding of the meaning of the new behaviours and terms introduced in the understatement penalty table. In addressing this main goal, the penalty tables and behaviours in legislation in New Zealand were compared to South Africa’s understatement penalty. The similarities and differences between the understatement penalty imposed in terms of Chapter 16 of the Tax Administration Act and the additional tax previously imposed in terms of section 76 of the Income Tax Act were also discussed to determine whether this would be of assistance in enabling a better understanding of the meaning of the behaviours and terms in section 223. Guidance on the interpretation of the various behaviours and terms was developed and a definition was proposed for the meaning of “bona fide inadvertent error” and “obstructive” to assist in the objective and consistent application of the understatement penalty table in relation to each shortfall identified. The proposed definition for “bona fide inadvertent error” is as follows: “An honest mistake made or simple oversight, which the taxpayer was not aware of, despite taking reasonable care and displaying a prudent attitude while making a genuine attempt to comply with all applicable tax obligations.” The definition for “obstructive” is proposed as: “Deliberately interfering with, causing difficulties (impeding) or delays in, or preventing the progress of a SARS audit or review.”
- Full Text:
- Date Issued: 2017
A comparative analysis of the use of participatory practices by indigenous trusts and mainstream development NGOs in Zvimba Communal Area Zimbabwe
- Authors: Mbanje, Bowden Bolt
- Date: 2020
- Subjects: Caritas Zimbabwe , Zvimba Community Share Ownership Trust (ZvCSOT) , Non-governmental organizations -- Zimbabwe -- Zvimba District , Community development -- Zimbabwe -- Zvimba District , Rural development -- Zimbabwe -- Zvimba District , Zvimba Communal Land (Zimbabwe)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167099 , vital:41437
- Description: This thesis compares the extent to which participatory practices have been used by Caritas Zimbabwe, a mainstream NGO, and the Zvimba Community Share Ownership Trust (ZvCSOT), an indigenous Trust, in Zvimba District, Zimbabwe. Participatory development initiatives are common practice in NGO and government development work in Zimbabwe. The thesis begins with a discussion of two aspects of participatory development (PD). Firstly, PD is discussed in relation to decentralization processes where central government transfers administrative and financial authority to sub-national government units in order to enhance the participation of rural communities in development interventions. Secondly, PD is discussed in relation to the increased role of NGOs in development work. During the 1980s and 1990s, shifts in development thinking resulted in NGOs being perceived as important actors who could attend to the development gaps left by an economically incapacitated state. Both NGOs and sub-national government units were seen to be closer to rural communities and so were thought to be in a better position to enhance the participation of these communities in meaningful development projects. An analysis of the practices of the NGO and CSOT under consideration in this study shows that while there has been much rhetorical commitment to participation, community participation in the development interventions of the NGO and the CSOT is inadequate. In introducing and implementing development interventions, there has been a tendency by both the NGO and CSOT to give priority to organizational preferences over local needs. While recognizing the participatory efforts made by mainstream development NGOs (Caritas in particular) and indigenous Trusts (Zvimba Community Share Ownership Trust in particular) in Zimbabwe, this thesis also considers the impact of other factors on participatory development initiatives. A major observation from the study is that in as much as we expect genuine participatory approaches which include grassroots communities’ inputs from the project’s conceptualization all the way to its evaluation, the challenge is that the elites at the higher level (central government and donor offices) have their own development preferences and interests while the elites at the lower levels (local government and NGO offices) also have their own priorities and needs. Consequently, local communities tend to be confined to implementing development projects foisted on them by elites at the higher level as well as those at the lower level. Worse still, the study shows that elites at the lowest level (community) sometimes hijack or take advantage of the imposed projects. Participation has been stalled by elites at various levels of the participatory development ladder. Thus, unless power imbalances are seriously addressed at all levels, participatory development will remain elusive.
- Full Text:
- Date Issued: 2020
- Authors: Mbanje, Bowden Bolt
- Date: 2020
- Subjects: Caritas Zimbabwe , Zvimba Community Share Ownership Trust (ZvCSOT) , Non-governmental organizations -- Zimbabwe -- Zvimba District , Community development -- Zimbabwe -- Zvimba District , Rural development -- Zimbabwe -- Zvimba District , Zvimba Communal Land (Zimbabwe)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/167099 , vital:41437
- Description: This thesis compares the extent to which participatory practices have been used by Caritas Zimbabwe, a mainstream NGO, and the Zvimba Community Share Ownership Trust (ZvCSOT), an indigenous Trust, in Zvimba District, Zimbabwe. Participatory development initiatives are common practice in NGO and government development work in Zimbabwe. The thesis begins with a discussion of two aspects of participatory development (PD). Firstly, PD is discussed in relation to decentralization processes where central government transfers administrative and financial authority to sub-national government units in order to enhance the participation of rural communities in development interventions. Secondly, PD is discussed in relation to the increased role of NGOs in development work. During the 1980s and 1990s, shifts in development thinking resulted in NGOs being perceived as important actors who could attend to the development gaps left by an economically incapacitated state. Both NGOs and sub-national government units were seen to be closer to rural communities and so were thought to be in a better position to enhance the participation of these communities in meaningful development projects. An analysis of the practices of the NGO and CSOT under consideration in this study shows that while there has been much rhetorical commitment to participation, community participation in the development interventions of the NGO and the CSOT is inadequate. In introducing and implementing development interventions, there has been a tendency by both the NGO and CSOT to give priority to organizational preferences over local needs. While recognizing the participatory efforts made by mainstream development NGOs (Caritas in particular) and indigenous Trusts (Zvimba Community Share Ownership Trust in particular) in Zimbabwe, this thesis also considers the impact of other factors on participatory development initiatives. A major observation from the study is that in as much as we expect genuine participatory approaches which include grassroots communities’ inputs from the project’s conceptualization all the way to its evaluation, the challenge is that the elites at the higher level (central government and donor offices) have their own development preferences and interests while the elites at the lower levels (local government and NGO offices) also have their own priorities and needs. Consequently, local communities tend to be confined to implementing development projects foisted on them by elites at the higher level as well as those at the lower level. Worse still, the study shows that elites at the lowest level (community) sometimes hijack or take advantage of the imposed projects. Participation has been stalled by elites at various levels of the participatory development ladder. Thus, unless power imbalances are seriously addressed at all levels, participatory development will remain elusive.
- Full Text:
- Date Issued: 2020
A comparative analysis with selected jurisdictions of structural challenges facing the South African office of the tax ombud
- Authors: Mothiba, Boitumelo Charity
- Date: 2020
- Subjects: South Africa. Office of the Tax Ombud , Tax administration and procdure -- South Africa , Taxpayer advocates -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/140360 , vital:37882
- Description: The Office of the Tax Ombud is critical in the protection of South African taxpayers' rights. The office has only been in existence for a little over five years and to ensure that it fulfils the purpose for which it was established, it must be properly structured. This includes that it ought to be independent from any external influence and manipulation. Any such external influence on the Tax Ombud creates the risk that the general public will lose confidence in the Tax Ombud as an independent recourse. The study, therefore, is designed to review the structure relating to the independence and powers of the South African Tax Ombud. The study assesses and evaluates the legislative safeguards of the structure of the Tax Ombud office in order to determine whether the legislative framework (the Tax Administration Act) safeguarding the Office of the Tax Ombud is adequate to ensure its independence and also to ensure a strengthened structure, without interference in the decision-making process of the office. To achieve this, a comparative analysis was made with selected foreign institutions of Tax Ombudsmen, or equivalent institutions, in order to draw from the best international practice. The study found that the structure of the Office of the Tax Ombud is relatively weak and does not fully provide the legislative powers to protect taxpayers from the well-resourced South African Revenue Service. The study also revealed that most of the institutional features in the structure of the South African Tax Ombud were found to be in line with standard international practice. The study has made recommendations aimed at strengthening the structure of the South African Tax Ombud by suggesting reforms in the legislative framework of the Tax Ombud.
- Full Text:
- Date Issued: 2020
- Authors: Mothiba, Boitumelo Charity
- Date: 2020
- Subjects: South Africa. Office of the Tax Ombud , Tax administration and procdure -- South Africa , Taxpayer advocates -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/140360 , vital:37882
- Description: The Office of the Tax Ombud is critical in the protection of South African taxpayers' rights. The office has only been in existence for a little over five years and to ensure that it fulfils the purpose for which it was established, it must be properly structured. This includes that it ought to be independent from any external influence and manipulation. Any such external influence on the Tax Ombud creates the risk that the general public will lose confidence in the Tax Ombud as an independent recourse. The study, therefore, is designed to review the structure relating to the independence and powers of the South African Tax Ombud. The study assesses and evaluates the legislative safeguards of the structure of the Tax Ombud office in order to determine whether the legislative framework (the Tax Administration Act) safeguarding the Office of the Tax Ombud is adequate to ensure its independence and also to ensure a strengthened structure, without interference in the decision-making process of the office. To achieve this, a comparative analysis was made with selected foreign institutions of Tax Ombudsmen, or equivalent institutions, in order to draw from the best international practice. The study found that the structure of the Office of the Tax Ombud is relatively weak and does not fully provide the legislative powers to protect taxpayers from the well-resourced South African Revenue Service. The study also revealed that most of the institutional features in the structure of the South African Tax Ombud were found to be in line with standard international practice. The study has made recommendations aimed at strengthening the structure of the South African Tax Ombud by suggesting reforms in the legislative framework of the Tax Ombud.
- Full Text:
- Date Issued: 2020
A comparative bioinformatic analysis of zinc binuclear cluster proteins
- Authors: Mthombeni, Jabulani S
- Date: 2005
- Subjects: Bioinformatics , Zinc proteins , GABA
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4004 , http://hdl.handle.net/10962/d1004064 , Bioinformatics , Zinc proteins , GABA
- Description: Members of the zinc binuclear cluster family are important fungal transcriptional regulators sharing a common DNA binding domain. Da181p is a pleotropic zinc binuclear cluster protein involved in the induction of the UGA genes required for the γ-aminobutyrate nitrogen catabolic pathway in Saccharomyces cerevisiae. The zinc binuclear cluster domain is indispensable for function in Da181p and little is known about other domains in this protein. The aim of the study was to explore the zinc binuclear cluster protein family using comparative bioinformatics as a complement to biochemical and structural approaches. A database of all zinc binuclear cluster proteins was composed. A total of 118 zinc binuclear proteins are reported in this work. Thirty nine previously unidentified zinc binuclear cluster proteins were found. Four homologues of Da181p were identified by homology searching. Important sequence motifs were identified in the aligned sequences of Da181p and its homologues. The coiled coil motif found in the Ga14p zinc binuclear cluster protein could not be identified in Da181p and its homologues. This suggested that Da181p did not dimerise through this structural motif as other zinc binuclear cluster proteins. Solvent accessible site that could be phosphorylated by protein kinase C or casein kinase II and the role of such sites in the possible regulation of Da181p function were discussed.
- Full Text:
- Date Issued: 2005
- Authors: Mthombeni, Jabulani S
- Date: 2005
- Subjects: Bioinformatics , Zinc proteins , GABA
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4004 , http://hdl.handle.net/10962/d1004064 , Bioinformatics , Zinc proteins , GABA
- Description: Members of the zinc binuclear cluster family are important fungal transcriptional regulators sharing a common DNA binding domain. Da181p is a pleotropic zinc binuclear cluster protein involved in the induction of the UGA genes required for the γ-aminobutyrate nitrogen catabolic pathway in Saccharomyces cerevisiae. The zinc binuclear cluster domain is indispensable for function in Da181p and little is known about other domains in this protein. The aim of the study was to explore the zinc binuclear cluster protein family using comparative bioinformatics as a complement to biochemical and structural approaches. A database of all zinc binuclear cluster proteins was composed. A total of 118 zinc binuclear proteins are reported in this work. Thirty nine previously unidentified zinc binuclear cluster proteins were found. Four homologues of Da181p were identified by homology searching. Important sequence motifs were identified in the aligned sequences of Da181p and its homologues. The coiled coil motif found in the Ga14p zinc binuclear cluster protein could not be identified in Da181p and its homologues. This suggested that Da181p did not dimerise through this structural motif as other zinc binuclear cluster proteins. Solvent accessible site that could be phosphorylated by protein kinase C or casein kinase II and the role of such sites in the possible regulation of Da181p function were discussed.
- Full Text:
- Date Issued: 2005
A comparative case study of the strategies used by grade one teachers who teach through the medium of English
- Authors: Jackson, Gail
- Date: 2004
- Subjects: Native language and education -- South Africa Language policy -- South Africa Language and education -- South Africa English language -- Study and teaching (Elementary) -- South Africa Multilingualism -- South Africa Education, Bilingual -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1941 , http://hdl.handle.net/10962/d1007855
- Description: This research project begins by exploring the problems surrounding the implementation of the 1997 Language in Education Policy (LiEP), and offers insight into why some schools, despite the promotion of additive bilingualism, choose English as the primary medium of instruction. It is a comparative case study of two Grade 1 classes in different situational contexts, which highlights the teaching strategies and language practices of teachers who teach predominantly non-English speakers through the medium of English. Research carried out through this case study illustrates the use of a wide range of teaching strategies, which assist young learners when learning through an additional language. In School A, thematic linking between different learning areas to maximise vocabulary development in both the mother tongue and the additional language, as well as repetition, recycling, scaffolding and contextualisation of content were found to be important. In addition, the use of questioning to elicit understanding, as well as classroom organisation and code-switching were strategies which assisted both the teacher and learners in this multilingual environment. In School B, class size, group work and the inclusion into the timetable of a wide range of diverse activities over and above the main learning areas, which provided opportunities for language development, were important considerations. In addition, routine, predictability and an attention to detail, in keeping with a form-focussed approach, aided the children in understanding the mechanics of literacy and guiding them towards becoming phonologically aware.
- Full Text:
- Date Issued: 2004
- Authors: Jackson, Gail
- Date: 2004
- Subjects: Native language and education -- South Africa Language policy -- South Africa Language and education -- South Africa English language -- Study and teaching (Elementary) -- South Africa Multilingualism -- South Africa Education, Bilingual -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1941 , http://hdl.handle.net/10962/d1007855
- Description: This research project begins by exploring the problems surrounding the implementation of the 1997 Language in Education Policy (LiEP), and offers insight into why some schools, despite the promotion of additive bilingualism, choose English as the primary medium of instruction. It is a comparative case study of two Grade 1 classes in different situational contexts, which highlights the teaching strategies and language practices of teachers who teach predominantly non-English speakers through the medium of English. Research carried out through this case study illustrates the use of a wide range of teaching strategies, which assist young learners when learning through an additional language. In School A, thematic linking between different learning areas to maximise vocabulary development in both the mother tongue and the additional language, as well as repetition, recycling, scaffolding and contextualisation of content were found to be important. In addition, the use of questioning to elicit understanding, as well as classroom organisation and code-switching were strategies which assisted both the teacher and learners in this multilingual environment. In School B, class size, group work and the inclusion into the timetable of a wide range of diverse activities over and above the main learning areas, which provided opportunities for language development, were important considerations. In addition, routine, predictability and an attention to detail, in keeping with a form-focussed approach, aided the children in understanding the mechanics of literacy and guiding them towards becoming phonologically aware.
- Full Text:
- Date Issued: 2004
A comparative developmental study of the fear of snakes
- Authors: Bartel, P R
- Date: 1972
- Subjects: Snakes , Fear
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3198 , http://hdl.handle.net/10962/d1009505 , Snakes , Fear
- Description: This study was conducted to determine the influence of age and culture on the fear of snakes. Five age groups, consisting of 20 White and 20 Xhosa subjects each, were tested. In addition to a behavioural and a GSR measure of fear, questionnaires were applied to determine the extent of the subjects' personal and vicarious aversive experiences of snakes and attitudes towards snakes. The behavioural measure showed a significant decrease in the fear of snakes between the 9 - 11 year and the 14 - 16 year White groups, while, for the Xhosa subjects, the fear of snakes increased significantly between the age groups 14 - 16 years and 18 - 20 years. The GSR measure showed a consistent level in the fear of snakes for White subjects. For the Xhosa subjects the mean GSR score for the 18 - 20 year .group was considerably higher than the means for the other age groups. The intensity of the fear of snakes for White and Xhosa subjects of the same age was remarkably similar. Xhosa subjects had significantly more negative attitudes towards snakes than white subjects. This finding was explained in terms of Whites having had greater opportunities to obtain factual information about snakes. No significant relationships were found between (a) the measures of the extent of the subjects' aversive experiences of snakes; (b) the degree of negative attitudes towards snakes; and the measures of the fear of snakes. On the basis of these measures, the etiology of the fear of snakes cannot be explained in terms of aversive experiences with snakes per se. The striking similarity of responses to a live snake by subjects from two widely different cultures suggests caution in an over-hasty dismissal of the theory of an innate fear of snakes.
- Full Text:
- Date Issued: 1972
- Authors: Bartel, P R
- Date: 1972
- Subjects: Snakes , Fear
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3198 , http://hdl.handle.net/10962/d1009505 , Snakes , Fear
- Description: This study was conducted to determine the influence of age and culture on the fear of snakes. Five age groups, consisting of 20 White and 20 Xhosa subjects each, were tested. In addition to a behavioural and a GSR measure of fear, questionnaires were applied to determine the extent of the subjects' personal and vicarious aversive experiences of snakes and attitudes towards snakes. The behavioural measure showed a significant decrease in the fear of snakes between the 9 - 11 year and the 14 - 16 year White groups, while, for the Xhosa subjects, the fear of snakes increased significantly between the age groups 14 - 16 years and 18 - 20 years. The GSR measure showed a consistent level in the fear of snakes for White subjects. For the Xhosa subjects the mean GSR score for the 18 - 20 year .group was considerably higher than the means for the other age groups. The intensity of the fear of snakes for White and Xhosa subjects of the same age was remarkably similar. Xhosa subjects had significantly more negative attitudes towards snakes than white subjects. This finding was explained in terms of Whites having had greater opportunities to obtain factual information about snakes. No significant relationships were found between (a) the measures of the extent of the subjects' aversive experiences of snakes; (b) the degree of negative attitudes towards snakes; and the measures of the fear of snakes. On the basis of these measures, the etiology of the fear of snakes cannot be explained in terms of aversive experiences with snakes per se. The striking similarity of responses to a live snake by subjects from two widely different cultures suggests caution in an over-hasty dismissal of the theory of an innate fear of snakes.
- Full Text:
- Date Issued: 1972
A comparative kinetic study of the reaction between chromium nitrate solutions and the carboxyl groups of acetate and collage
- Authors: Russell, Allan Edward
- Date: 1962
- Subjects: Chemical kinetics , Chromium , Spectrophotometry , Electrophoresis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4493 , http://hdl.handle.net/10962/d1013101
- Description: The kinetics of the coordination reaction between the carboxyl group of the acetate radical and the trivalent chromium ion has been examined by independent methods at a temperature selected to yield reasonably accurate rate data. The study has been extended to an examination of the rate of chromium "fixation" by the carboxyl groups of hide collagen in a series of miniature tannages carried out under similar conditions for comparative purposes. The effect of olation of the chromium ions in solution on the kinetics of t he coordination reaction has also been examined. The rate of coordination of the acetate radical was followed by solvent extraction and spectrophotometric techniques over a range of concentration and pH levels. The rate data revealed a reaction having typical mass-action characteristics, the rate of reaction depending on the concentration levels of the chromium ion and the ionised acetate radical. An attempt made to distinguish a differential reaction rate in the case of a parallel reaction series using boiled and aged chromium nitrate reactant solutions, failed to reveal any significant differences between the series. The reactant solutions gave absorption spectra characteristic of the trivalent chromium ion with maxima in the 420 mµ and 570 mµ wavelength regions. The changes in optical density occurring in the vicinity of the maxima were followed spectrophotometrically, the height of the 570 mµ being found to increase during the course of reaction, while the height of the 420 mµ peak decreased. The variation in optical density at the 570 mµ peak was found to be directly related to the increase in concentration of the product complex in solution in accordance with the Baer-Bougher law, while the decrease in the height of the 420 mµ peak was related to the properties of unolated OH groups associated with the chromium complex as governed by pH and olation changes during the course of reaction. Boiled and aged chromium nitrate solutions gave reactant solutions having initial optical densities greater than those of the correspending fresh reactant solutions at the 570 mµ peak, and less than those of the fresh solutions at the 420 mµ peak. During the course of reaction, however, the two series converged to the same values. The equilibrium reaction solutions were subjected to paper electrophoretic study which indicated that all tho chromium was present in the form of cationic species. This finding was in accordance with stoicheiometric indications in the solvent extraction studies where coordination in a l : 1 ratio was reflected, giving rise to positively charged complex ions only. Making due allowance for band spreading the numbers of species predicted from the kinetic studies correspond with the electrophoretic patterns found. Application of the classical second order kinetic expression to the solvent extraction rate data, yielded plots having two distinctly linear sections, apparently indicating consecutive second order processes occurring in solution, contrary to the findings of previous workers who assign a first order mechanism to the reaction. This finding was consistent with the view that in the case of both the fresh and aged series, reaction consisted of successive coordination of an acetate radical to each chromium atom of a diol complex. Second order rate "constants" were calculated for each step and their dependency on pH level demonstrated. The findings of Hamm et al that these were first order reactions independent of acetate co'ncentration are believed to be due to their use of a large excess of acetate in their experiments. The kinetic study was further extended to an examination of the rate of "fixation"of trivalent chromium by the carboxyl groups of hide collagen under comparable conditions in a series of miniaturv tanning experiments in which the tannage substrate was provided in each of two physical forms:- (a) As hide powder where surface development was large, and (b) as prepared pelt pieces in which the fibrous weave pattern was retained. In view of the heterogeneity of the tannage systems, remarkable similarity was observed in the reaction course when compared with that of the acetate coordination studies, particularly in the case of the hide powder tannages. The dependency of the tannage rate data upon concentration and pH conditions was also found to be the same as in the case of the pure chemical system. The exact correlation between the rate data for the tannage and pure chemical systems was demonstrated by means of correlation plots. Close correlation was revealed in the case of hide powder tannage while the smaller degree of correlation observed in the case of the pelt tannage systems was attributed to the modifying effects of diffusion, particularly on the initial reaction velocity. The effect of using boiled and aged chromium solutions in the tannages was to increase the initial rate of chroniill!l "fixation" apparently due to tho coordination of a dial species at each coordination site. After the initial reaction period, the two series showed a tendency to converge as in the case of the spectrophotometric studies on the acetate reaction. The convergence trend was regarded as indicative of the tendency for the chromium in fresh solutions to under go rapid olation to the ame level as in the boiled and aged solutions. The experimental observations made on the various systems lead to the following conclusions:- (a) The mechanism of coordination of the acetate radical ttrivalent chromium appears to involve the successive coordination of ligand to each of the chromium atoms of a diol complex, both coordination steps proceeding by second order reaction mechanisms. (b) At the pH levels at which the reaction is carried out, the formation of elated bodios is rapid so that reaction in the case of both fresh and aged solutions essentially occurs between an elated species and the ionised acetate radical. (c) Modificati0ns in the absorption spectrum of the reactant solution at the 570 mµ peak are directly related to coordination, while changes at the 420 mµ peak are related to the formation of loosely-bound hydroxo chromium compounds, the concentrations of which depend on the pH level. (d) The mechanism of chromium fixation in hide is essentially similar to that operating in the case of coordination of the acetate radical to chromium, involving attachment of chromium to the side chain acid r sidues of collagen. (e ) The effect of olation is to enhance the rate of chromium fixation by hide protein during the initial reaction stages and to render possible bridge formation between adjacent side chains by secondary coordination during the latter reaction stages. (f) Where pelt pieces are used instead of hide powder, the initial rate of chromium fixation is dominated by the rate of diffusion of chromium into the fibrous structure. It should be stressed that the observations made on the various reaction systems cannot be regarded as exhaustive and the conclusions are subject to further confirmation. Consequently, the present study is essentially of a preliminary nature, but it is felt that the need for further investigation along similar lines has been demonstrated.
- Full Text:
- Date Issued: 1962
- Authors: Russell, Allan Edward
- Date: 1962
- Subjects: Chemical kinetics , Chromium , Spectrophotometry , Electrophoresis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4493 , http://hdl.handle.net/10962/d1013101
- Description: The kinetics of the coordination reaction between the carboxyl group of the acetate radical and the trivalent chromium ion has been examined by independent methods at a temperature selected to yield reasonably accurate rate data. The study has been extended to an examination of the rate of chromium "fixation" by the carboxyl groups of hide collagen in a series of miniature tannages carried out under similar conditions for comparative purposes. The effect of olation of the chromium ions in solution on the kinetics of t he coordination reaction has also been examined. The rate of coordination of the acetate radical was followed by solvent extraction and spectrophotometric techniques over a range of concentration and pH levels. The rate data revealed a reaction having typical mass-action characteristics, the rate of reaction depending on the concentration levels of the chromium ion and the ionised acetate radical. An attempt made to distinguish a differential reaction rate in the case of a parallel reaction series using boiled and aged chromium nitrate reactant solutions, failed to reveal any significant differences between the series. The reactant solutions gave absorption spectra characteristic of the trivalent chromium ion with maxima in the 420 mµ and 570 mµ wavelength regions. The changes in optical density occurring in the vicinity of the maxima were followed spectrophotometrically, the height of the 570 mµ being found to increase during the course of reaction, while the height of the 420 mµ peak decreased. The variation in optical density at the 570 mµ peak was found to be directly related to the increase in concentration of the product complex in solution in accordance with the Baer-Bougher law, while the decrease in the height of the 420 mµ peak was related to the properties of unolated OH groups associated with the chromium complex as governed by pH and olation changes during the course of reaction. Boiled and aged chromium nitrate solutions gave reactant solutions having initial optical densities greater than those of the correspending fresh reactant solutions at the 570 mµ peak, and less than those of the fresh solutions at the 420 mµ peak. During the course of reaction, however, the two series converged to the same values. The equilibrium reaction solutions were subjected to paper electrophoretic study which indicated that all tho chromium was present in the form of cationic species. This finding was in accordance with stoicheiometric indications in the solvent extraction studies where coordination in a l : 1 ratio was reflected, giving rise to positively charged complex ions only. Making due allowance for band spreading the numbers of species predicted from the kinetic studies correspond with the electrophoretic patterns found. Application of the classical second order kinetic expression to the solvent extraction rate data, yielded plots having two distinctly linear sections, apparently indicating consecutive second order processes occurring in solution, contrary to the findings of previous workers who assign a first order mechanism to the reaction. This finding was consistent with the view that in the case of both the fresh and aged series, reaction consisted of successive coordination of an acetate radical to each chromium atom of a diol complex. Second order rate "constants" were calculated for each step and their dependency on pH level demonstrated. The findings of Hamm et al that these were first order reactions independent of acetate co'ncentration are believed to be due to their use of a large excess of acetate in their experiments. The kinetic study was further extended to an examination of the rate of "fixation"of trivalent chromium by the carboxyl groups of hide collagen under comparable conditions in a series of miniaturv tanning experiments in which the tannage substrate was provided in each of two physical forms:- (a) As hide powder where surface development was large, and (b) as prepared pelt pieces in which the fibrous weave pattern was retained. In view of the heterogeneity of the tannage systems, remarkable similarity was observed in the reaction course when compared with that of the acetate coordination studies, particularly in the case of the hide powder tannages. The dependency of the tannage rate data upon concentration and pH conditions was also found to be the same as in the case of the pure chemical system. The exact correlation between the rate data for the tannage and pure chemical systems was demonstrated by means of correlation plots. Close correlation was revealed in the case of hide powder tannage while the smaller degree of correlation observed in the case of the pelt tannage systems was attributed to the modifying effects of diffusion, particularly on the initial reaction velocity. The effect of using boiled and aged chromium solutions in the tannages was to increase the initial rate of chroniill!l "fixation" apparently due to tho coordination of a dial species at each coordination site. After the initial reaction period, the two series showed a tendency to converge as in the case of the spectrophotometric studies on the acetate reaction. The convergence trend was regarded as indicative of the tendency for the chromium in fresh solutions to under go rapid olation to the ame level as in the boiled and aged solutions. The experimental observations made on the various systems lead to the following conclusions:- (a) The mechanism of coordination of the acetate radical ttrivalent chromium appears to involve the successive coordination of ligand to each of the chromium atoms of a diol complex, both coordination steps proceeding by second order reaction mechanisms. (b) At the pH levels at which the reaction is carried out, the formation of elated bodios is rapid so that reaction in the case of both fresh and aged solutions essentially occurs between an elated species and the ionised acetate radical. (c) Modificati0ns in the absorption spectrum of the reactant solution at the 570 mµ peak are directly related to coordination, while changes at the 420 mµ peak are related to the formation of loosely-bound hydroxo chromium compounds, the concentrations of which depend on the pH level. (d) The mechanism of chromium fixation in hide is essentially similar to that operating in the case of coordination of the acetate radical to chromium, involving attachment of chromium to the side chain acid r sidues of collagen. (e ) The effect of olation is to enhance the rate of chromium fixation by hide protein during the initial reaction stages and to render possible bridge formation between adjacent side chains by secondary coordination during the latter reaction stages. (f) Where pelt pieces are used instead of hide powder, the initial rate of chromium fixation is dominated by the rate of diffusion of chromium into the fibrous structure. It should be stressed that the observations made on the various reaction systems cannot be regarded as exhaustive and the conclusions are subject to further confirmation. Consequently, the present study is essentially of a preliminary nature, but it is felt that the need for further investigation along similar lines has been demonstrated.
- Full Text:
- Date Issued: 1962
A comparative mineralogical and geochemical study of manganese deposits in the Postmasburg Manganese Field, South Africa
- Authors: Thokoa, Mamello
- Date: 2020
- Subjects: Manganese ores -- South Africa -- Postmasburg , Geology -- South Africa -- Postmasburg
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167609 , vital:41496
- Description: The Postmasburg Manganese Field (PMF), located in the Northern Cape Province of South Africa, is host to some of the largest deposits of iron and manganese metal in the world. These deposits are restricted to a geographical area known as the Maremane Dome, an anticlinal structure defined by folded dolostones of the Campbellrand Subgroup and overlying ironformations of the Asbestos Hills Subgroup of the Neoarchaean-Palaeproterozoic Transvaal Supergroup. Manganese ores associated with the Maremane Dome have been divided into two major classes in the literature: the Wolhaarkop breccia-hosted massive ores of the Eastern Belt, as well as the shale-associated ores of the Western Belt. The Eastern Belt ores have been classed as siliceous in nature, while the Western Belt deposits are reported to be typically ferruginous. These divisions were made based on their varying bulk chemical and mineralogical compositions in conjunction with their different stratigraphic sub-settings. Presently, both deposit types are explained as variants of supergene mineralisation that would have formed through a combination of intense ancient lateritic weathering in the presence of oxygen, extreme residual enrichments in Mn (and Fe), and accumulations in karstic depressions at the expense of underlying manganiferous dolostones. This study revisits these deposits and their origins by sampling representative end-member examples of both Eastern Belt and Western Belt manganese ores in both drillcore (localities Khumani, McCarthy and Leeuwfontein), and outcrop sections (locality Bishop). In an attempt to provide new insights into the processes responsible for the genesis of these deposits, the possibility of hydrothermal influences and associated metasomatic replacement processes is explored in this thesis. This was achieved using standard petrographic and mineralogical techniques (transmitted and reflected light microscopy, XRD , SEM-EDS and EMPA), coupled with bulk-rock geochemical analysis of the same samples using a combination of XRF and LAICP- MS analyses. Combination of field observations, petrographic and mineralogical results, and geochemical data allowed for the re-assessment of the different ore types encountered in the field. Comparative considerations made between the bulk geochemistry of the different end-member ore types revealed no clear-cut compositional distinctions and therefore do not support existing classifications between siliceous (Eastern Belt) and ferruginous (Western Belt) ores. This is supported by trace and REE element data as well, when normalised against average shale. The geochemistry reflects the bulk mineralogy of the ores which is broadly comparable, whereby braunite and hematite appear to be dominant co-existing minerals in both Eastern Belt (Khumani) and Western Belt (Bishop) ore. In the case of the McCarthy locality, manganese ore is cryptomelane-rich and appears to have involved recent supergene overprint over Eastern Belt type ore, whereas the Leeuwfontein ores are far more ferruginous than at any other locality studied and therefore represent a more complex, hybrid type of oxide-rich Mn mineralisation (mainly bixbyitic) within massive hematite iron ore. In terms of gangue mineralogy, the ores share some close similarities through the omnipresence of barite, and the abundance of alkalirich silicate minerals. Eastern Belt ores contain abundant albite and serandite whereas the main alkali-rich phase in Western Belt ores is the mineral ephesite. In both cases, Na contents are therefore high at several wt% levels registered in selected samples. The afore-mentioned alkali enrichments have been variously reported for both these deposit types. The occurrence of high alkalis cannot be explained through classic residual or aqueous supergene systems of ore formation, as proposed in prevailing genetic models in the literature. Together with the detection of halogens such as F and Br through SEM-EDS analyses of ore from both belts, the alkali enrichments suggest possible hydrothermal processes of ore formation involving circulation of metalliferous sodic brines. Selected textural evidence from samples from both ore belts lends support to fluid-related models and allow the proposal for a common hydrothermal-replacement model to have been responsible for ore formation across the broader Maremane Dome region.
- Full Text:
- Date Issued: 2020
- Authors: Thokoa, Mamello
- Date: 2020
- Subjects: Manganese ores -- South Africa -- Postmasburg , Geology -- South Africa -- Postmasburg
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/167609 , vital:41496
- Description: The Postmasburg Manganese Field (PMF), located in the Northern Cape Province of South Africa, is host to some of the largest deposits of iron and manganese metal in the world. These deposits are restricted to a geographical area known as the Maremane Dome, an anticlinal structure defined by folded dolostones of the Campbellrand Subgroup and overlying ironformations of the Asbestos Hills Subgroup of the Neoarchaean-Palaeproterozoic Transvaal Supergroup. Manganese ores associated with the Maremane Dome have been divided into two major classes in the literature: the Wolhaarkop breccia-hosted massive ores of the Eastern Belt, as well as the shale-associated ores of the Western Belt. The Eastern Belt ores have been classed as siliceous in nature, while the Western Belt deposits are reported to be typically ferruginous. These divisions were made based on their varying bulk chemical and mineralogical compositions in conjunction with their different stratigraphic sub-settings. Presently, both deposit types are explained as variants of supergene mineralisation that would have formed through a combination of intense ancient lateritic weathering in the presence of oxygen, extreme residual enrichments in Mn (and Fe), and accumulations in karstic depressions at the expense of underlying manganiferous dolostones. This study revisits these deposits and their origins by sampling representative end-member examples of both Eastern Belt and Western Belt manganese ores in both drillcore (localities Khumani, McCarthy and Leeuwfontein), and outcrop sections (locality Bishop). In an attempt to provide new insights into the processes responsible for the genesis of these deposits, the possibility of hydrothermal influences and associated metasomatic replacement processes is explored in this thesis. This was achieved using standard petrographic and mineralogical techniques (transmitted and reflected light microscopy, XRD , SEM-EDS and EMPA), coupled with bulk-rock geochemical analysis of the same samples using a combination of XRF and LAICP- MS analyses. Combination of field observations, petrographic and mineralogical results, and geochemical data allowed for the re-assessment of the different ore types encountered in the field. Comparative considerations made between the bulk geochemistry of the different end-member ore types revealed no clear-cut compositional distinctions and therefore do not support existing classifications between siliceous (Eastern Belt) and ferruginous (Western Belt) ores. This is supported by trace and REE element data as well, when normalised against average shale. The geochemistry reflects the bulk mineralogy of the ores which is broadly comparable, whereby braunite and hematite appear to be dominant co-existing minerals in both Eastern Belt (Khumani) and Western Belt (Bishop) ore. In the case of the McCarthy locality, manganese ore is cryptomelane-rich and appears to have involved recent supergene overprint over Eastern Belt type ore, whereas the Leeuwfontein ores are far more ferruginous than at any other locality studied and therefore represent a more complex, hybrid type of oxide-rich Mn mineralisation (mainly bixbyitic) within massive hematite iron ore. In terms of gangue mineralogy, the ores share some close similarities through the omnipresence of barite, and the abundance of alkalirich silicate minerals. Eastern Belt ores contain abundant albite and serandite whereas the main alkali-rich phase in Western Belt ores is the mineral ephesite. In both cases, Na contents are therefore high at several wt% levels registered in selected samples. The afore-mentioned alkali enrichments have been variously reported for both these deposit types. The occurrence of high alkalis cannot be explained through classic residual or aqueous supergene systems of ore formation, as proposed in prevailing genetic models in the literature. Together with the detection of halogens such as F and Br through SEM-EDS analyses of ore from both belts, the alkali enrichments suggest possible hydrothermal processes of ore formation involving circulation of metalliferous sodic brines. Selected textural evidence from samples from both ore belts lends support to fluid-related models and allow the proposal for a common hydrothermal-replacement model to have been responsible for ore formation across the broader Maremane Dome region.
- Full Text:
- Date Issued: 2020
A comparative photostability study of four propyl piperzine-substituted phenothiazines
- Authors: Drummond, Patricia Mary
- Date: 1997
- Subjects: Phenothiazine
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3756 , http://hdl.handle.net/10962/d1003234 , Phenothiazine
- Description: Four structurally related phenothiazines available in South Africa in a variety of dosage forms and as fine chemicals were investigated to ascertain whether their structural differences in terms of the 2-chloro-/ trifluoromethyl-substituents on the phenothiazine nucleus and the methyl-/ ß-hydroxethyl groups on the piperazine ring accouning for the differences in pharmacological activity can be correlated with their photostability².The four propyl piperazine-substituted derivatives are ranked in the following decreasing order of neuroleptic activity: fluphenazine> trifluoperazine> perphenazine > rochlorperazine. In order to assess their photostability an HPLC method was developed and validated for linearity, accuracy and precision, selectivity, limit of detection and quantitation and ruggedness. Preliminary solution photostudies under controlled light conditions (UV, sunlight, fluorescent light) indicated that the rate of degradation followed first-order kinetics with perphenazine the most susceptible to.photodegradation under all light conditions studied. In vitro and in vivo metabolism yielding the 5-sulphoxide and its reported presence on decomposition of the phenothiazines25 led to the development of a synthetic procedure suitable for the sutphoxides of all four derivatives based on the method proposed by Owens et al. in order to provide standards for comparison in the photostudies⁷. Since ICH regulations require that impurities> 0.1 % are examined and identified⁷⁴ and semi-preparative isolation of photoproducts proved unsuccessful, LC-MS having been well documented for structural.elucidation⁷⁵ ⁷⁵ ⁷⁶ ⁷⁷ was used to characterize solution (UV, sunlight, fluorescent light) and preliminary solid (UV) photostudies. The chloroderivatives underwent dechlorination and sulphoxidation with subsequent photosubstitution in the case of prochlorperazine to yield the 2-hydroxy derivative and sulphoxidation of the dechloro-derivative of perphenazine. The sulphoxides of both trifluoperazine and fluphenazine were formed with further oxidation to the respective sulphones occurring. Preliminary solid state (UV) photostudies showed fluphenazine to be the least stable with 30.71 % degradation as opposed to 7.57% for prochlorperazine, 4.28% for perphenazine and 7.10% for trifluoperazine witn sulphoxidation observed to be. the major degradation pathway. Since in vitro metabolism of perazine derivatives is reported to occur via N-oxidation, N-demethylation, sulphoxidation and aromatic hydroxylation¹⁸ it does appear that there is some correlation between metabolic and photoproducts. However the fact that solution (UV) photostudies indicates trifluoperazine to be the most and perphenazine the least stable does not concur with the proposed order of pharmacological activity.
- Full Text:
- Date Issued: 1997
- Authors: Drummond, Patricia Mary
- Date: 1997
- Subjects: Phenothiazine
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3756 , http://hdl.handle.net/10962/d1003234 , Phenothiazine
- Description: Four structurally related phenothiazines available in South Africa in a variety of dosage forms and as fine chemicals were investigated to ascertain whether their structural differences in terms of the 2-chloro-/ trifluoromethyl-substituents on the phenothiazine nucleus and the methyl-/ ß-hydroxethyl groups on the piperazine ring accouning for the differences in pharmacological activity can be correlated with their photostability².The four propyl piperazine-substituted derivatives are ranked in the following decreasing order of neuroleptic activity: fluphenazine> trifluoperazine> perphenazine > rochlorperazine. In order to assess their photostability an HPLC method was developed and validated for linearity, accuracy and precision, selectivity, limit of detection and quantitation and ruggedness. Preliminary solution photostudies under controlled light conditions (UV, sunlight, fluorescent light) indicated that the rate of degradation followed first-order kinetics with perphenazine the most susceptible to.photodegradation under all light conditions studied. In vitro and in vivo metabolism yielding the 5-sulphoxide and its reported presence on decomposition of the phenothiazines25 led to the development of a synthetic procedure suitable for the sutphoxides of all four derivatives based on the method proposed by Owens et al. in order to provide standards for comparison in the photostudies⁷. Since ICH regulations require that impurities> 0.1 % are examined and identified⁷⁴ and semi-preparative isolation of photoproducts proved unsuccessful, LC-MS having been well documented for structural.elucidation⁷⁵ ⁷⁵ ⁷⁶ ⁷⁷ was used to characterize solution (UV, sunlight, fluorescent light) and preliminary solid (UV) photostudies. The chloroderivatives underwent dechlorination and sulphoxidation with subsequent photosubstitution in the case of prochlorperazine to yield the 2-hydroxy derivative and sulphoxidation of the dechloro-derivative of perphenazine. The sulphoxides of both trifluoperazine and fluphenazine were formed with further oxidation to the respective sulphones occurring. Preliminary solid state (UV) photostudies showed fluphenazine to be the least stable with 30.71 % degradation as opposed to 7.57% for prochlorperazine, 4.28% for perphenazine and 7.10% for trifluoperazine witn sulphoxidation observed to be. the major degradation pathway. Since in vitro metabolism of perazine derivatives is reported to occur via N-oxidation, N-demethylation, sulphoxidation and aromatic hydroxylation¹⁸ it does appear that there is some correlation between metabolic and photoproducts. However the fact that solution (UV) photostudies indicates trifluoperazine to be the most and perphenazine the least stable does not concur with the proposed order of pharmacological activity.
- Full Text:
- Date Issued: 1997
A comparative polarimetric study of the 43 GHz and 86 GHz SiO masers toward the supergiant star VY CMa
- Authors: Richter, Laura
- Date: 2012
- Subjects: Masers Supergiant stars Polarization (Light) Very long baseline interferometry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5454 , http://hdl.handle.net/10962/d1005239
- Description: The aim of this thesis is to perform observational tests of SiO maser polarisation and excitation models, using component-level comparisons of multiple SiO maser transitions in the 43 GHz and 86 GHz bands at milliarcsecond resolution. These observations reqwre very long baseline interferometric imaging with very accurate polarimetric calibration. The supergiant star VY CMa was chosen as the object of this study due to its high SiO maser luminosity, many detected SiO maser lines, and intrinsic scientific interest. Two epochs of full-polarisation VLBA observations of VY CMa were performed. The Epoch 2 observations were reduced using several new data reduction methods developed as part of this work, and designed specifically to improve the accuracy of circular polarisation calibration of spectral-line VLBI observations at millimetre wavelengths. The accuracy is estimated to be better than 1% using these methods. The Epoch 2 images show a concentration of v= l and v=2 J= 1-0 SiO masers to the east and northeast of the assumed stellar position. The v=l J=2-1 masers were more evenly distributed around the star, with a notable lack of emission in the northeast. There is appreciable spatial overlap between these three lines. The nature of the overlap is generally consistent with the predictions of hydrodynamical circumstellar SiO maser simulations. Where the v=l J = 1-0 and J =2-1 features overlap, the v=l J = 2-1 emission is usually considerably weaker. This is not predicted by current hydrodynamical models, but can be explained in the context of collisional pumping in a low density environment. Six observational tests of weak-splitting maser polarisation models were performed, including intercomparisons of linear polarisation in the v=l J=1-0 and J=2-1lines, linear polarisation versus saturation level, linear polarisation versus distance from the star, circular polarisation in the v= l J = 1-0 and J=2-1 lines, circular versus linear polarisation and modeling of ~ 900 electric-vector position angle rotations. The polarisation model tests generally do not support non-Zeeman circular polarisation mechanisms. For the linear polarisation tests, the results are more consistent with models that predict similar linear polarisation across transitions. The scientific importance of these tests is described in detail and avenues for future work are described.
- Full Text:
- Date Issued: 2012
- Authors: Richter, Laura
- Date: 2012
- Subjects: Masers Supergiant stars Polarization (Light) Very long baseline interferometry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5454 , http://hdl.handle.net/10962/d1005239
- Description: The aim of this thesis is to perform observational tests of SiO maser polarisation and excitation models, using component-level comparisons of multiple SiO maser transitions in the 43 GHz and 86 GHz bands at milliarcsecond resolution. These observations reqwre very long baseline interferometric imaging with very accurate polarimetric calibration. The supergiant star VY CMa was chosen as the object of this study due to its high SiO maser luminosity, many detected SiO maser lines, and intrinsic scientific interest. Two epochs of full-polarisation VLBA observations of VY CMa were performed. The Epoch 2 observations were reduced using several new data reduction methods developed as part of this work, and designed specifically to improve the accuracy of circular polarisation calibration of spectral-line VLBI observations at millimetre wavelengths. The accuracy is estimated to be better than 1% using these methods. The Epoch 2 images show a concentration of v= l and v=2 J= 1-0 SiO masers to the east and northeast of the assumed stellar position. The v=l J=2-1 masers were more evenly distributed around the star, with a notable lack of emission in the northeast. There is appreciable spatial overlap between these three lines. The nature of the overlap is generally consistent with the predictions of hydrodynamical circumstellar SiO maser simulations. Where the v=l J = 1-0 and J =2-1 features overlap, the v=l J = 2-1 emission is usually considerably weaker. This is not predicted by current hydrodynamical models, but can be explained in the context of collisional pumping in a low density environment. Six observational tests of weak-splitting maser polarisation models were performed, including intercomparisons of linear polarisation in the v=l J=1-0 and J=2-1lines, linear polarisation versus saturation level, linear polarisation versus distance from the star, circular polarisation in the v= l J = 1-0 and J=2-1 lines, circular versus linear polarisation and modeling of ~ 900 electric-vector position angle rotations. The polarisation model tests generally do not support non-Zeeman circular polarisation mechanisms. For the linear polarisation tests, the results are more consistent with models that predict similar linear polarisation across transitions. The scientific importance of these tests is described in detail and avenues for future work are described.
- Full Text:
- Date Issued: 2012