Portfolio of original compositions
- Authors: Nabal, Ruhan
- Date: 2018
- Subjects: Composition (Music) Music -- South Africa Suites (Orchestra , Piano music Marimba music
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: http://hdl.handle.net/10948/23858 , vital:30630
- Description: This Orchestral Suite was inspired by the art illustrations from Brian Froud’s book ‘Good Faeries Bad Faeries’, where each piece in the suite represents a drawing from his book, portraying three good faeries and three bad and is in many ways a tone poem. Each pieces calls for different orchestration to create individual colour to make each piece unique. Permission was not consented to include the drawings. The line-up is as follows:I. Waters of Wisdom – Overture to the faerie realm (good)II. The Thoughts of the Melancholic Faerie – She contemplates ofpast and present (bad)III. A Banshee Passing – the idea of death as coming unknowingly and going quietly (bad)IV. Introduction to Faerie Lilu – clearing the mist V. The Faerie Lilu – the provocateur of restlessness – she inspires wild dreams, lost fantasies and gives artists their sparks of genius (bad) VI. A Cluster of Hedgerow Pixies – They are very mischievous – in a (good) way.VII. The Dance of the Oboe Faerie – a Finale (good). While he dances, he also sings of the faerie realm.A number of composers inspired me to pursue such a work, and firstly G. Holst has left his mark on me. The first and sixth movement was inspired by the ‘Planets’. The fifth movement is actually in homage to the French composer Frank Martin with the composition ‘Petite symphonie’ where he displays the piano and harpsichord – as I have done. The second and third movements are attempts to portray film music, such as composers H. Zimmerman and D.Elfman. The last movement has many neo-classical elements displayed and I. Stravinsky had a notable influence on this piece. All the composers mentioned here have contributed in more than one piece at some point in time.The theme of the work, the magical theme, always makes me reminisce my childhood where I would in amazement wonder about my grandmothers glorious garden in search of all that is magical, and composing this took me back to that time of innocent, child-like wonder.
- Full Text:
- Date Issued: 2018
- Authors: Nabal, Ruhan
- Date: 2018
- Subjects: Composition (Music) Music -- South Africa Suites (Orchestra , Piano music Marimba music
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: http://hdl.handle.net/10948/23858 , vital:30630
- Description: This Orchestral Suite was inspired by the art illustrations from Brian Froud’s book ‘Good Faeries Bad Faeries’, where each piece in the suite represents a drawing from his book, portraying three good faeries and three bad and is in many ways a tone poem. Each pieces calls for different orchestration to create individual colour to make each piece unique. Permission was not consented to include the drawings. The line-up is as follows:I. Waters of Wisdom – Overture to the faerie realm (good)II. The Thoughts of the Melancholic Faerie – She contemplates ofpast and present (bad)III. A Banshee Passing – the idea of death as coming unknowingly and going quietly (bad)IV. Introduction to Faerie Lilu – clearing the mist V. The Faerie Lilu – the provocateur of restlessness – she inspires wild dreams, lost fantasies and gives artists their sparks of genius (bad) VI. A Cluster of Hedgerow Pixies – They are very mischievous – in a (good) way.VII. The Dance of the Oboe Faerie – a Finale (good). While he dances, he also sings of the faerie realm.A number of composers inspired me to pursue such a work, and firstly G. Holst has left his mark on me. The first and sixth movement was inspired by the ‘Planets’. The fifth movement is actually in homage to the French composer Frank Martin with the composition ‘Petite symphonie’ where he displays the piano and harpsichord – as I have done. The second and third movements are attempts to portray film music, such as composers H. Zimmerman and D.Elfman. The last movement has many neo-classical elements displayed and I. Stravinsky had a notable influence on this piece. All the composers mentioned here have contributed in more than one piece at some point in time.The theme of the work, the magical theme, always makes me reminisce my childhood where I would in amazement wonder about my grandmothers glorious garden in search of all that is magical, and composing this took me back to that time of innocent, child-like wonder.
- Full Text:
- Date Issued: 2018
Possible future jobs in the republic of South Africa by 2030
- Authors: Kasvosve, Johanis
- Date: 2018
- Subjects: Industries -- Technological innovations , Labor market -- South Africa Employment (Economic theory)
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/30660 , vital:31008
- Description: The 21st century has experienced dramatic, fundamental and unprecedented changes that have seen many organisations having to reconsider their competitive strategies in order to remain relevant in the market place. Within the context of South Africa, these changes have resulted in the disappearance, dwindling or expansion of some jobs. The dawn of the 21st century marked the beginning of the Fourth Industrial Revolutions (Industry 4.0). Although Industry 4.0 can bring about great promises for the future, the patterns of consumption, production and employment created by it also pose substantive challenges in the form of technological unemployment requiring proactive adaptation by businesses, governments and individuals. This study aimed at identifying possible future jobs in the Republic of South Africa as we transition to 2030. Causal Layered Analysis (CLA) and Environmental Scanning were identified as the preferred methodologies to be utilised to respond to the research objectives of this study. A detailed literature study was undertaken to evaluate the existing body of knowledge on the research topic. The literature study revealed that technological advancements, economic, urbanisation, globalisation, economic, political, demographic and environmental factors are the major determinants of future jobs. Chapter 4 dealt with the application of the CLA. This research ought to be understood in the context that utility of CLA is not in predicting the future of jobs but in creating transformative spaces for the creation of alternative futures that are desirable for the country as we transition to 2030. Some of the key findings emanating for this study are that Industry 4.0 is poised to render routine manufacturing jobs redundant. Furthermore, the advancements in technology are posed to result in massive employment opportunities for developers of web tolls, applications, hardware design and engineers and those working in web-based businesses. More jobs are likely to emanate from greening the economy. Progressive emancipation of women is likely to result in occupations and working x arrangements that facilitate a successful compromise between work life and private lives resulting in social care jobs. A number of strategic considerations and recommendations were also sponsored with a view to respond to the trends shaping the future of jobs in South Africa.
- Full Text:
- Date Issued: 2018
- Authors: Kasvosve, Johanis
- Date: 2018
- Subjects: Industries -- Technological innovations , Labor market -- South Africa Employment (Economic theory)
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/30660 , vital:31008
- Description: The 21st century has experienced dramatic, fundamental and unprecedented changes that have seen many organisations having to reconsider their competitive strategies in order to remain relevant in the market place. Within the context of South Africa, these changes have resulted in the disappearance, dwindling or expansion of some jobs. The dawn of the 21st century marked the beginning of the Fourth Industrial Revolutions (Industry 4.0). Although Industry 4.0 can bring about great promises for the future, the patterns of consumption, production and employment created by it also pose substantive challenges in the form of technological unemployment requiring proactive adaptation by businesses, governments and individuals. This study aimed at identifying possible future jobs in the Republic of South Africa as we transition to 2030. Causal Layered Analysis (CLA) and Environmental Scanning were identified as the preferred methodologies to be utilised to respond to the research objectives of this study. A detailed literature study was undertaken to evaluate the existing body of knowledge on the research topic. The literature study revealed that technological advancements, economic, urbanisation, globalisation, economic, political, demographic and environmental factors are the major determinants of future jobs. Chapter 4 dealt with the application of the CLA. This research ought to be understood in the context that utility of CLA is not in predicting the future of jobs but in creating transformative spaces for the creation of alternative futures that are desirable for the country as we transition to 2030. Some of the key findings emanating for this study are that Industry 4.0 is poised to render routine manufacturing jobs redundant. Furthermore, the advancements in technology are posed to result in massive employment opportunities for developers of web tolls, applications, hardware design and engineers and those working in web-based businesses. More jobs are likely to emanate from greening the economy. Progressive emancipation of women is likely to result in occupations and working x arrangements that facilitate a successful compromise between work life and private lives resulting in social care jobs. A number of strategic considerations and recommendations were also sponsored with a view to respond to the trends shaping the future of jobs in South Africa.
- Full Text:
- Date Issued: 2018
Possible futures for agricultural financing in sub-Saharan Africa towards 2055
- Authors: Oberholster, Jacobus Hoon
- Date: 2018
- Subjects: Agriculture -- Africa, Sub-Saharan -- Finance , Agricultural industries -- Africa, Sub-Saharan , Agricultural productivity -- Africa, Sub-Saharan
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23069 , vital:30403
- Description: The research developed four possible future scenarios for agricultural financing in Sub-Saharan Africa towards 2055, namely the “Rising Sun”, “Two Wolves”, “The Left Wing and the Right Wing”, and the “Two Moons” scenarios. The scenarios aim to stimulate new thoughts on an inclusive and broader development approach to agricultural financing, and to identify gaps in the knowledge about a broad range of research issues relating to the level of complexity with regard to the decision-making environment in agricultural financing. The scenarios are developed, according to a strict and predetermined process, which is guided by the Six-Pillars approach of futures studies. A conceptual futures study model for agricultural financing was also developed to guide and clarify the way in which the research on agricultural financing can be integrated into the body of existing futures study theory. The research begins with a comprehensive environmental scan, from which various trends and driving forces emerged. The causal-layered analysis (CLA) method is then used in tandem with other futures-study techniques, such as the futures triangle and emerging issues analyses, to guide the process of knowledge creation about the future of agricultural financing. A real-time Delphi study was also conducted to validate and prioritise the megatrends and driving forces that emerged from the research. Subsequently, the research presents four future scenarios that aim to provide a better understanding of the future of agricultural financing in Sub-Saharan Africa over next 40 years. The research presents agriculture as a multi-dimensional sector that fulfils different roles and functions in especially rural communities in Sub-Saharan Africa, which contribute to the perceived riskiness of agricultural financing. The scenarios illustrate how conditions for agricultural development and agricultural financing can develop and change in the region towards 2055. Furthermore, it provides useful insight into the drivers for change and how to anticipate these changes. The Delphibased scenario research also allowed the aggregation of expert knowledge, which can be used to inform decision-makers in the financial-service sector to test the robustness and appropriateness of existing business models and strategies. The scenarios can also be used as a starting point for financial-service providers and other key stakeholders to identify the future challenges and to maximise the emerging business and development opportunities, as offered by the agricultural sector in Sub-Saharan Africa. The research closes a research gap with regard to scenario development in agricultural financing in Sub-Saharan Africa within the context of the globaldevelopment agenda. The research looks at the future of agricultural financing in Sub-Saharan Africa over the next 40 years from a decision-maker’s point of view; and it provides key insights into especially the rural agricultural financial challenge in the region. A cornerstone of the research is to align policy initiatives and the business strategies of financial service providers with the vision of a broadened view of rural finance and increased financial inclusion in agriculture. The scenarios offer a starting point to develop new and more inclusive agricultural financing strategies that have the ability to speed up income convergence and economic diversification, especially with regard to rural economies in Sub-Saharan Africa that are heavily dependent on agriculture and its related industries. The research also makes a meaningful contribution by introducing a forward-looking, systems-thinking approach to agricultural financing, which is necessary to evaluate the sector’s financing needs within the context of modern food systems that are increasingly being characterised by increased levels of chain co-ordination and value creation. Subsequently, disruptive digital technologies and innovations in agricultural value-chain financing emerged as the most significant driving forces for agricultural financing in Sub-Saharan Africa towards 2055.
- Full Text:
- Date Issued: 2018
- Authors: Oberholster, Jacobus Hoon
- Date: 2018
- Subjects: Agriculture -- Africa, Sub-Saharan -- Finance , Agricultural industries -- Africa, Sub-Saharan , Agricultural productivity -- Africa, Sub-Saharan
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23069 , vital:30403
- Description: The research developed four possible future scenarios for agricultural financing in Sub-Saharan Africa towards 2055, namely the “Rising Sun”, “Two Wolves”, “The Left Wing and the Right Wing”, and the “Two Moons” scenarios. The scenarios aim to stimulate new thoughts on an inclusive and broader development approach to agricultural financing, and to identify gaps in the knowledge about a broad range of research issues relating to the level of complexity with regard to the decision-making environment in agricultural financing. The scenarios are developed, according to a strict and predetermined process, which is guided by the Six-Pillars approach of futures studies. A conceptual futures study model for agricultural financing was also developed to guide and clarify the way in which the research on agricultural financing can be integrated into the body of existing futures study theory. The research begins with a comprehensive environmental scan, from which various trends and driving forces emerged. The causal-layered analysis (CLA) method is then used in tandem with other futures-study techniques, such as the futures triangle and emerging issues analyses, to guide the process of knowledge creation about the future of agricultural financing. A real-time Delphi study was also conducted to validate and prioritise the megatrends and driving forces that emerged from the research. Subsequently, the research presents four future scenarios that aim to provide a better understanding of the future of agricultural financing in Sub-Saharan Africa over next 40 years. The research presents agriculture as a multi-dimensional sector that fulfils different roles and functions in especially rural communities in Sub-Saharan Africa, which contribute to the perceived riskiness of agricultural financing. The scenarios illustrate how conditions for agricultural development and agricultural financing can develop and change in the region towards 2055. Furthermore, it provides useful insight into the drivers for change and how to anticipate these changes. The Delphibased scenario research also allowed the aggregation of expert knowledge, which can be used to inform decision-makers in the financial-service sector to test the robustness and appropriateness of existing business models and strategies. The scenarios can also be used as a starting point for financial-service providers and other key stakeholders to identify the future challenges and to maximise the emerging business and development opportunities, as offered by the agricultural sector in Sub-Saharan Africa. The research closes a research gap with regard to scenario development in agricultural financing in Sub-Saharan Africa within the context of the globaldevelopment agenda. The research looks at the future of agricultural financing in Sub-Saharan Africa over the next 40 years from a decision-maker’s point of view; and it provides key insights into especially the rural agricultural financial challenge in the region. A cornerstone of the research is to align policy initiatives and the business strategies of financial service providers with the vision of a broadened view of rural finance and increased financial inclusion in agriculture. The scenarios offer a starting point to develop new and more inclusive agricultural financing strategies that have the ability to speed up income convergence and economic diversification, especially with regard to rural economies in Sub-Saharan Africa that are heavily dependent on agriculture and its related industries. The research also makes a meaningful contribution by introducing a forward-looking, systems-thinking approach to agricultural financing, which is necessary to evaluate the sector’s financing needs within the context of modern food systems that are increasingly being characterised by increased levels of chain co-ordination and value creation. Subsequently, disruptive digital technologies and innovations in agricultural value-chain financing emerged as the most significant driving forces for agricultural financing in Sub-Saharan Africa towards 2055.
- Full Text:
- Date Issued: 2018
Possible futures for transport in South Africa towards 2035
- Authors: Mnqeta, Qawekazi Wanda
- Date: 2018
- Subjects: Transportation -- South Africa , Transportation and state -- South Africa Urban transportation -- South Africa Automobile industry and trade -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/22746 , vital:30071
- Description: It is evident that there is a great dissatisfaction with the current model of transport as the level of accidents continue to rise. The containment on carbon emission levels are illusive and transport congestion is becoming impossible to handle. The number of cars in cities is increasing rapidly, resulting in increased traffic congestion, less mobility, poor air quality and more road accidents. In the National Development Plan (NDP), one of the challenges identified is that despite a slowdown in the growth within urban areas, 14 million people are projected to move to South African cities between 2010 and 2050 (UN-Habitat, 2014).This will exert pressure on service delivery by municipalities – including transport and transport infrastructure. A large proportion of these new urban residents will be poor, further enhancing the pressure. Transportation networks or systems are therefore key to the spatial transformation of South Africa’s urban areas. Although there has been significant progress in some cities in delivering new public transport infrastructure, the major shift from supporting private cars to incentivising public transport is yet to happen. The NDP vision for urban South Africa is that by 2030, South Africa should observe meaningful and measurable progress in reviving rural areas and in creating more functionally integrated, balanced and vibrant urban settlements. For this to happen, it is said that the country must clarify and relentlessly pursue a national vision for spatial development, sharpen the instruments for achieving this vision and build the required capabilities in the state and among citizens (The Presidency of South Africa, 2011). The outcomes of this analysis of future studies theory and practice supported the argument presented at the beginning of this research that there is robust requirement for a fundamental shift in the ways and methods of planning the future of South Africa’s transport industry towards 2035.
- Full Text:
- Date Issued: 2018
- Authors: Mnqeta, Qawekazi Wanda
- Date: 2018
- Subjects: Transportation -- South Africa , Transportation and state -- South Africa Urban transportation -- South Africa Automobile industry and trade -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: http://hdl.handle.net/10948/22746 , vital:30071
- Description: It is evident that there is a great dissatisfaction with the current model of transport as the level of accidents continue to rise. The containment on carbon emission levels are illusive and transport congestion is becoming impossible to handle. The number of cars in cities is increasing rapidly, resulting in increased traffic congestion, less mobility, poor air quality and more road accidents. In the National Development Plan (NDP), one of the challenges identified is that despite a slowdown in the growth within urban areas, 14 million people are projected to move to South African cities between 2010 and 2050 (UN-Habitat, 2014).This will exert pressure on service delivery by municipalities – including transport and transport infrastructure. A large proportion of these new urban residents will be poor, further enhancing the pressure. Transportation networks or systems are therefore key to the spatial transformation of South Africa’s urban areas. Although there has been significant progress in some cities in delivering new public transport infrastructure, the major shift from supporting private cars to incentivising public transport is yet to happen. The NDP vision for urban South Africa is that by 2030, South Africa should observe meaningful and measurable progress in reviving rural areas and in creating more functionally integrated, balanced and vibrant urban settlements. For this to happen, it is said that the country must clarify and relentlessly pursue a national vision for spatial development, sharpen the instruments for achieving this vision and build the required capabilities in the state and among citizens (The Presidency of South Africa, 2011). The outcomes of this analysis of future studies theory and practice supported the argument presented at the beginning of this research that there is robust requirement for a fundamental shift in the ways and methods of planning the future of South Africa’s transport industry towards 2035.
- Full Text:
- Date Issued: 2018
Postgraduate writing groups as spaces of agency development
- Oluwole, David O, Achadu, A, Asfour, Fouad-Martin, Chakona, Gamuchirai, Mason, Paul, Mataruse, P, McKenna, Sioux
- Authors: Oluwole, David O , Achadu, A , Asfour, Fouad-Martin , Chakona, Gamuchirai , Mason, Paul , Mataruse, P , McKenna, Sioux
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187194 , vital:44578 , xlink:href="https://doi.org/10.20853/32-6-2963"
- Description: Academic writing is a peculiar phenomenon – it varies greatly from discipline to discipline and its requirements are rarely made overt. Taking on the writing practices of the academy has implications for identity and it is thus unsurprising that it is seen to be a risky endeavour. This article analyses the experiences of postgraduate scholars who have participated in writing groups that meet weekly to read each other’s work and provide supportive critique. Thirty-two people provided detailed, anonymous evaluations of their writing groups and these were studied using a discourse analysis. Three main findings are discussed here. Firstly, writing circles allowed for academic writing development to be engaged with as a social practice, where the disciplinary norms could be made more explicit through peer deliberation, and where they could also be challenged. Secondly, the lack of hierarchical power in the writing groups was key to making safe spaces for agency development, and also for providing positive peer pressure whereby participants were spurred on to work on their writing. Thirdly, the fact that the groups were interdisciplinary, within cognate disciplinary families, provided an interesting challenge in that the students had to consider what these non-specialist readers would or would not understand. This process assisted students in clarifying their writing. Participants’ evaluation of the writing groups revealed an overall sense that these contributed to postgraduate student wellbeing and were places of significant agential development.
- Full Text:
- Date Issued: 2018
- Authors: Oluwole, David O , Achadu, A , Asfour, Fouad-Martin , Chakona, Gamuchirai , Mason, Paul , Mataruse, P , McKenna, Sioux
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187194 , vital:44578 , xlink:href="https://doi.org/10.20853/32-6-2963"
- Description: Academic writing is a peculiar phenomenon – it varies greatly from discipline to discipline and its requirements are rarely made overt. Taking on the writing practices of the academy has implications for identity and it is thus unsurprising that it is seen to be a risky endeavour. This article analyses the experiences of postgraduate scholars who have participated in writing groups that meet weekly to read each other’s work and provide supportive critique. Thirty-two people provided detailed, anonymous evaluations of their writing groups and these were studied using a discourse analysis. Three main findings are discussed here. Firstly, writing circles allowed for academic writing development to be engaged with as a social practice, where the disciplinary norms could be made more explicit through peer deliberation, and where they could also be challenged. Secondly, the lack of hierarchical power in the writing groups was key to making safe spaces for agency development, and also for providing positive peer pressure whereby participants were spurred on to work on their writing. Thirdly, the fact that the groups were interdisciplinary, within cognate disciplinary families, provided an interesting challenge in that the students had to consider what these non-specialist readers would or would not understand. This process assisted students in clarifying their writing. Participants’ evaluation of the writing groups revealed an overall sense that these contributed to postgraduate student wellbeing and were places of significant agential development.
- Full Text:
- Date Issued: 2018
Postpartum depression as defence against criminal liability
- Crafford, Krisascha, David, Desiree
- Authors: Crafford, Krisascha , David, Desiree
- Date: 2018
- Subjects: Postpartum depression -- South Africa , Mothers -- Mental health -- South Africa Female offenders -- South Africa Feminist criminology
- Language: English
- Type: Thesis , Masters , LLM`
- Identifier: http://hdl.handle.net/10948/38648 , vital:34863
- Description: The dissertation addresses the phenomenon of postpartum depression (and especially its most severe form of postpartum psychosis) against the backdrop of the defense of pathological criminal incapacity (the defense of mental illness, also known as insanity defense) the submission is made that, in the instance where a mother with postpartum depression, and especially postpartum psychosis causes the death of her infant or child such an accused could raise the defense of mental illness. This is due to the impact of the affliction on her mental facilities caused by the condition she was suffering from at the time of causing the death of her infant or child, such condition could render her incapable of distinguishing between right and wrong to act in accordance with such appreciation. If she can prove this, she cannot be held criminally liable for her actions, due to the absence of the required means rea element.
- Full Text:
- Date Issued: 2018
- Authors: Crafford, Krisascha , David, Desiree
- Date: 2018
- Subjects: Postpartum depression -- South Africa , Mothers -- Mental health -- South Africa Female offenders -- South Africa Feminist criminology
- Language: English
- Type: Thesis , Masters , LLM`
- Identifier: http://hdl.handle.net/10948/38648 , vital:34863
- Description: The dissertation addresses the phenomenon of postpartum depression (and especially its most severe form of postpartum psychosis) against the backdrop of the defense of pathological criminal incapacity (the defense of mental illness, also known as insanity defense) the submission is made that, in the instance where a mother with postpartum depression, and especially postpartum psychosis causes the death of her infant or child such an accused could raise the defense of mental illness. This is due to the impact of the affliction on her mental facilities caused by the condition she was suffering from at the time of causing the death of her infant or child, such condition could render her incapable of distinguishing between right and wrong to act in accordance with such appreciation. If she can prove this, she cannot be held criminally liable for her actions, due to the absence of the required means rea element.
- Full Text:
- Date Issued: 2018
Potable water production from atmospheric vapour using an ejector evacuated solar powered refrigeration system
- Authors: Cawood, John Henry
- Date: 2018
- Subjects: Solar energy , Solar radiation
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/23481 , vital:30567
- Description: This research project explores the possibility of using solar radiation energy to produce safe liquid water through the condensation of atmospheric water vapour for human consumption, livestock watering and also for small scale high value crop irrigation. The research activities are comprised of a literature study, comparison of similar devices in use, a design and prototyping exercise, a measure of development work to enhance the performance of the prototype and testing in Al-Batinah province in the Sultanate of Oman, where the author is currently on a work assignment. This dissertation describes the research activities performed to answer the following question: ‘Is it possible to economically produce sufficient quantities of liquid water from atmospheric vapour using only heat energy from the sun?’ This question poses a further two questions which need to be answered in the literature study. These are: ‘What is an economical price for clean drinking water?’ and ‘What is a sufficient quantity of water?’ The purpose of producing liquid water from atmospheric water vapour is an attempt to develop the technology to harvest an alternative and almost inexhaustible water source. The reason for requiring a new source of water is due to the fact that the available fresh water resources of the world are diminishing due to pollution, extensive utilisation and salination. Several references indicate that the problem is compounding itself due the increasing demand on a diminishing resource, with deepening negative effects on agriculture1, health2, economy3, industry and lifestyle4. Many future scenarios depict clean water as a scarce and expensive commodity, unaffordable to many. The condensation of atmospheric vapour is not a new concept. The literature study explores historical attempts to achieve this, as well as detailing the shortcomings of contemporary vapour condensation units as the modern state of the art. This survey covers the spectrum from large versions deployed by military and remote area construction operations to produce water for all purposes, to small desktop electrical water producing machines. The focus of the research is on a more environmentally conscious process, attempting to use a simple ejector driven device with sunshine as the energy source and water as the refrigerant. A further environmental enhancement of the concept is that of designing the machine to last for an extremely long working life, thereby diluting the carbon footprint of manufacture over a great number of years. A portion of the research is devoted to the development of a basic model which takes into account the climatic and meteorological variables to accurately predict a water harvest. The development of the model is then used to optimise the process, narrow the variability of assumptions and assist with the design. The model also serves to predict the performance of the unit in other locations under different prevailing climatic conditions. A design specification and a prototype are produced and tested. Finally the design is scrutinised using value engineering principles to reduce cost, effort and environmental impact and also to reduce the overall cost to provide a more economically viable appliance. The prototype device used in this study will use a collector area of 1 square meter, roughly equivalent to 1000 Watts of solar power under ideal conditions.
- Full Text:
- Date Issued: 2018
- Authors: Cawood, John Henry
- Date: 2018
- Subjects: Solar energy , Solar radiation
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/23481 , vital:30567
- Description: This research project explores the possibility of using solar radiation energy to produce safe liquid water through the condensation of atmospheric water vapour for human consumption, livestock watering and also for small scale high value crop irrigation. The research activities are comprised of a literature study, comparison of similar devices in use, a design and prototyping exercise, a measure of development work to enhance the performance of the prototype and testing in Al-Batinah province in the Sultanate of Oman, where the author is currently on a work assignment. This dissertation describes the research activities performed to answer the following question: ‘Is it possible to economically produce sufficient quantities of liquid water from atmospheric vapour using only heat energy from the sun?’ This question poses a further two questions which need to be answered in the literature study. These are: ‘What is an economical price for clean drinking water?’ and ‘What is a sufficient quantity of water?’ The purpose of producing liquid water from atmospheric water vapour is an attempt to develop the technology to harvest an alternative and almost inexhaustible water source. The reason for requiring a new source of water is due to the fact that the available fresh water resources of the world are diminishing due to pollution, extensive utilisation and salination. Several references indicate that the problem is compounding itself due the increasing demand on a diminishing resource, with deepening negative effects on agriculture1, health2, economy3, industry and lifestyle4. Many future scenarios depict clean water as a scarce and expensive commodity, unaffordable to many. The condensation of atmospheric vapour is not a new concept. The literature study explores historical attempts to achieve this, as well as detailing the shortcomings of contemporary vapour condensation units as the modern state of the art. This survey covers the spectrum from large versions deployed by military and remote area construction operations to produce water for all purposes, to small desktop electrical water producing machines. The focus of the research is on a more environmentally conscious process, attempting to use a simple ejector driven device with sunshine as the energy source and water as the refrigerant. A further environmental enhancement of the concept is that of designing the machine to last for an extremely long working life, thereby diluting the carbon footprint of manufacture over a great number of years. A portion of the research is devoted to the development of a basic model which takes into account the climatic and meteorological variables to accurately predict a water harvest. The development of the model is then used to optimise the process, narrow the variability of assumptions and assist with the design. The model also serves to predict the performance of the unit in other locations under different prevailing climatic conditions. A design specification and a prototype are produced and tested. Finally the design is scrutinised using value engineering principles to reduce cost, effort and environmental impact and also to reduce the overall cost to provide a more economically viable appliance. The prototype device used in this study will use a collector area of 1 square meter, roughly equivalent to 1000 Watts of solar power under ideal conditions.
- Full Text:
- Date Issued: 2018
Potential eco-physiological and phytosociological impacts of fracking on the vegetation of the Karoo, Eastern Cape, South Africa
- Authors: Martin, Kristen
- Date: 2018
- Subjects: Hydraulic fracturing -- Environmental aspects -- South Africa -- Eastern Cape , Germination Plant ecology Plant communities
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/31852 , vital:31853
- Description: Hydraulic fracturing or fracking is a technique that is used to extract gas from low permeable rocks. Large volumes of fluids (typically water combined with chemicals and sand) are injected at high pressure into rock formations to fracture them, allowing the gas to be released. A number of criticisms have come to light regarding the potential environmental impacts of this process. One concern is that there will be contamination of groundwater due to the toxicity of the chemicals used in the fracking process. There have been limited studies on the effects of fracking fluid on vegetation and no studies on South African vegetation specifically. The effects of fracking chemicals on the germination success and photosynthetic efficiency of plants was investigated for species common in areas earmarked for possible future hydraulic fracturing in the Karoo, South Africa. Germination of seeds was unaffected by these fracking fluids at application concentration in most species, but dwarf shrub and grass seeds were found to be sensitive to contamination. A single application treatment of plants with fracking fluid resulted in mortality in 50% of the species with reduced photosynthetic efficiency and growth in some of the surviving species. Long term continual treatment with diluted fracking fluids had an even greater effect on mortality and photosynthetic efficiency than a single high dose. The major vegetation types of the proposed fracking footprint were surveyed and analyses of the species, communities and their physiognomy were used to predict the tolerance of the Karoo vegetation to degradation resulting from shale gas development. An understanding of the sensitivity of vegetation was obtained from impacts of livestock on the vegetation. The results indicated that Grassland communities are least tolerant to degradation, Albany Thicket communities more tolerant and Nama-Karoo communities most tolerant. Escarpment Thickets were shown to be Nama-Karoo rather than Albany Thicket elements, and should be grouped with the former when considering the impacts of fracking.
- Full Text:
- Date Issued: 2018
- Authors: Martin, Kristen
- Date: 2018
- Subjects: Hydraulic fracturing -- Environmental aspects -- South Africa -- Eastern Cape , Germination Plant ecology Plant communities
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/31852 , vital:31853
- Description: Hydraulic fracturing or fracking is a technique that is used to extract gas from low permeable rocks. Large volumes of fluids (typically water combined with chemicals and sand) are injected at high pressure into rock formations to fracture them, allowing the gas to be released. A number of criticisms have come to light regarding the potential environmental impacts of this process. One concern is that there will be contamination of groundwater due to the toxicity of the chemicals used in the fracking process. There have been limited studies on the effects of fracking fluid on vegetation and no studies on South African vegetation specifically. The effects of fracking chemicals on the germination success and photosynthetic efficiency of plants was investigated for species common in areas earmarked for possible future hydraulic fracturing in the Karoo, South Africa. Germination of seeds was unaffected by these fracking fluids at application concentration in most species, but dwarf shrub and grass seeds were found to be sensitive to contamination. A single application treatment of plants with fracking fluid resulted in mortality in 50% of the species with reduced photosynthetic efficiency and growth in some of the surviving species. Long term continual treatment with diluted fracking fluids had an even greater effect on mortality and photosynthetic efficiency than a single high dose. The major vegetation types of the proposed fracking footprint were surveyed and analyses of the species, communities and their physiognomy were used to predict the tolerance of the Karoo vegetation to degradation resulting from shale gas development. An understanding of the sensitivity of vegetation was obtained from impacts of livestock on the vegetation. The results indicated that Grassland communities are least tolerant to degradation, Albany Thicket communities more tolerant and Nama-Karoo communities most tolerant. Escarpment Thickets were shown to be Nama-Karoo rather than Albany Thicket elements, and should be grouped with the former when considering the impacts of fracking.
- Full Text:
- Date Issued: 2018
Potential impact and host range of Pereskiophaga brasiliensis Anderson (Curculionidae): a new candidate biological control agent for the control of Pereskia aculeata Miller (Cactaceae) in South Africa
- Authors: Mdodana, Lumka Anita
- Date: 2018
- Subjects: Curculionidae -- South Africa , Cactus -- South Africa , Biological pest control agents , Alien plants-- South Africa , Pereskiophaga brasiliensis Anderson (Curculionidae) , Pereskia aculeata Miller (Cactaceae)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62350 , vital:28157
- Description: Pereskia aculeata Miller (Cactaceae) is a damaging invasive alien plant in South Africa that has negative impacts to indigenous biodiversity and ecosystem functioning. Mechanical and chemical control are not effective against P. aculeata so biological control is considered the only viable option. Two biological control agents, the leaf-feeding beetle Phenrica guerini Bechyne (Chrysomelidae) and the stem-wilting bug Catorhintha schaffneri (Coreidae), have been released in South Africa thus far. Post-release evaluations have indicated that P. guerini will not reduce P. aculeata densities to acceptable levels alone, while C. schaffneri was released very recently, so it is too soon to determine how effective that agent will be. Even if C. schaffneri is extremely damaging, it is likely that further agents will be required to reduce the densities of P. aculeata to acceptable levels within a reasonable time-scale. Additional agents should target the woody stems of P. aculeata which are not impacted by the damage of either of the released agents. Pereskiophaga brasiliensis Anderson (Curculionidae) is a promising potential candidate agent that feeds on the thick woody stems of the plant in the larval stage. Climatic matching, genetic matching and field based host specificity observations all indicated that P. brasiliensis was a promising candidate. In this study, the impact of P. brasiliensis to the target weed, P. aculeata, was quantified under quarantine conditions to determine whether it was sufficiently damaging to warrant release. This was followed by host specificity testing to determine whether P. brasiliensis was suitably host specific for release in South Africa. Impact studies indicated that P. brasiliensis was damaging to P. aculeata at insect densities that would be expected in the field. Pereskiophaga brasiliensis reduced the number of leaves of P. aculeata to a greater extent than it reduced shoot lengths, but both plant parameters were significantly reduced due to the feeding damage from the insect. This suggests that the damage from P. brasiliensis may be compatible with that of C. schaffneri which reduces shoot length to a greater degree than the number of leaves. Pereskiophaga brasiliensis is therefore sufficiently damaging to warrant release, and although interaction studies with the other agents would be required, it is expected that it should complement other existing agents. Although P. brasiliensis is sufficiently damaging, at present the host specificity data indicates that it is not suitably specific for release in South Africa because oviposition and larval development to the adult stage was recorded on both indigenous and alien plant species within the families Cactaceae and Basellaceae. This non-target feeding was recorded during no-choice tests, which are very conservative, but significant non-target damage and development to the adult stage was recorded on an indigenous plant from a different family to the target weed. Further host specificity testing, including paired and multiple choice tests, are required to confirm the broad host range of P. brasiliensis. Other biological control agents that damage the woody stems of P. aculeata should be considered. The stem-borer, Acanthodoxus machacalis (Cerambycidae) is considered the most promising of the other candidate agents as it can be sourced from a climatically matched region where genetically suitable P. aculeata plants are found, it is sufficiently damaging to the woody stems of P. aculeata and there is no evidence that the species has a broad host range. Acanthodoxus machacalis should be sourced from Rio de Janeiro, Brazil, and imported into quarantine in South Africa for host specificity testing.
- Full Text:
- Date Issued: 2018
- Authors: Mdodana, Lumka Anita
- Date: 2018
- Subjects: Curculionidae -- South Africa , Cactus -- South Africa , Biological pest control agents , Alien plants-- South Africa , Pereskiophaga brasiliensis Anderson (Curculionidae) , Pereskia aculeata Miller (Cactaceae)
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/62350 , vital:28157
- Description: Pereskia aculeata Miller (Cactaceae) is a damaging invasive alien plant in South Africa that has negative impacts to indigenous biodiversity and ecosystem functioning. Mechanical and chemical control are not effective against P. aculeata so biological control is considered the only viable option. Two biological control agents, the leaf-feeding beetle Phenrica guerini Bechyne (Chrysomelidae) and the stem-wilting bug Catorhintha schaffneri (Coreidae), have been released in South Africa thus far. Post-release evaluations have indicated that P. guerini will not reduce P. aculeata densities to acceptable levels alone, while C. schaffneri was released very recently, so it is too soon to determine how effective that agent will be. Even if C. schaffneri is extremely damaging, it is likely that further agents will be required to reduce the densities of P. aculeata to acceptable levels within a reasonable time-scale. Additional agents should target the woody stems of P. aculeata which are not impacted by the damage of either of the released agents. Pereskiophaga brasiliensis Anderson (Curculionidae) is a promising potential candidate agent that feeds on the thick woody stems of the plant in the larval stage. Climatic matching, genetic matching and field based host specificity observations all indicated that P. brasiliensis was a promising candidate. In this study, the impact of P. brasiliensis to the target weed, P. aculeata, was quantified under quarantine conditions to determine whether it was sufficiently damaging to warrant release. This was followed by host specificity testing to determine whether P. brasiliensis was suitably host specific for release in South Africa. Impact studies indicated that P. brasiliensis was damaging to P. aculeata at insect densities that would be expected in the field. Pereskiophaga brasiliensis reduced the number of leaves of P. aculeata to a greater extent than it reduced shoot lengths, but both plant parameters were significantly reduced due to the feeding damage from the insect. This suggests that the damage from P. brasiliensis may be compatible with that of C. schaffneri which reduces shoot length to a greater degree than the number of leaves. Pereskiophaga brasiliensis is therefore sufficiently damaging to warrant release, and although interaction studies with the other agents would be required, it is expected that it should complement other existing agents. Although P. brasiliensis is sufficiently damaging, at present the host specificity data indicates that it is not suitably specific for release in South Africa because oviposition and larval development to the adult stage was recorded on both indigenous and alien plant species within the families Cactaceae and Basellaceae. This non-target feeding was recorded during no-choice tests, which are very conservative, but significant non-target damage and development to the adult stage was recorded on an indigenous plant from a different family to the target weed. Further host specificity testing, including paired and multiple choice tests, are required to confirm the broad host range of P. brasiliensis. Other biological control agents that damage the woody stems of P. aculeata should be considered. The stem-borer, Acanthodoxus machacalis (Cerambycidae) is considered the most promising of the other candidate agents as it can be sourced from a climatically matched region where genetically suitable P. aculeata plants are found, it is sufficiently damaging to the woody stems of P. aculeata and there is no evidence that the species has a broad host range. Acanthodoxus machacalis should be sourced from Rio de Janeiro, Brazil, and imported into quarantine in South Africa for host specificity testing.
- Full Text:
- Date Issued: 2018
Potential latitudinal variation in orodigestive tract cancers in Africa
- Adeola, H A, Adefuye, A O, Jimoh, S A
- Authors: Adeola, H A , Adefuye, A O , Jimoh, S A
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5280 , vital:44428 , http://www.samj.org.za/index.php/samj/article/view/12259
- Description: Background. Previous studies have alluded to a causal relationship between pathological entities and geographical variations, but there is a paucity of studies from Africa discussing the effect of latitudinal variation on orodigestive cancers in this region. It seems plausible that the burden of orodigestive cancer would differ as a result of variations in diet, cultural habits, climate and environmental conditions down the length of Africa. Objectives. To analyse regional variations in prevalence, incidence and mortality data in the global cancer statistics database (GLOBOCAN 2012) curated by the World Health Organization and the International Agency for Research on Cancer. Basic descriptive statistical tools were used to depict regional variations in cancer morbidity and mortality. Methods. Data on 13 African countries between longitude 20⁰ and 30⁰ east and latitude 35⁰ north and 35⁰ south were examined for variation in age-standardised orodigestive cancer prevalence, incidence and mortality. Possible regional causes for orodigestive tract cancer development were investigated. Data on lip and oral cavity, oesophageal, gastric, colorectal, liver, gallbladder and pancreatic cancers in the 13 countries were compared. Results. Our empirical findings from this preliminary study support the notion that the incidence and prevalence of orodigestive cancers vary within Africa. This effect may be due to environmental, economic, political and possibly genetic factors. Conclusions. Considering the heterogeneity of the above factors across Africa, disbursement of funding for cancer research and therapy in Africa should be focused in terms of regional variations to make best use of the fiscal allocation by African governments, non-governmental organisations and international agencies.
- Full Text:
- Date Issued: 2018
- Authors: Adeola, H A , Adefuye, A O , Jimoh, S A
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5280 , vital:44428 , http://www.samj.org.za/index.php/samj/article/view/12259
- Description: Background. Previous studies have alluded to a causal relationship between pathological entities and geographical variations, but there is a paucity of studies from Africa discussing the effect of latitudinal variation on orodigestive cancers in this region. It seems plausible that the burden of orodigestive cancer would differ as a result of variations in diet, cultural habits, climate and environmental conditions down the length of Africa. Objectives. To analyse regional variations in prevalence, incidence and mortality data in the global cancer statistics database (GLOBOCAN 2012) curated by the World Health Organization and the International Agency for Research on Cancer. Basic descriptive statistical tools were used to depict regional variations in cancer morbidity and mortality. Methods. Data on 13 African countries between longitude 20⁰ and 30⁰ east and latitude 35⁰ north and 35⁰ south were examined for variation in age-standardised orodigestive cancer prevalence, incidence and mortality. Possible regional causes for orodigestive tract cancer development were investigated. Data on lip and oral cavity, oesophageal, gastric, colorectal, liver, gallbladder and pancreatic cancers in the 13 countries were compared. Results. Our empirical findings from this preliminary study support the notion that the incidence and prevalence of orodigestive cancers vary within Africa. This effect may be due to environmental, economic, political and possibly genetic factors. Conclusions. Considering the heterogeneity of the above factors across Africa, disbursement of funding for cancer research and therapy in Africa should be focused in terms of regional variations to make best use of the fiscal allocation by African governments, non-governmental organisations and international agencies.
- Full Text:
- Date Issued: 2018
Potential use of carbon nanotubes as a nanofiller for natural rubber latex condoms
- Authors: Agbakoba, Victor Chike
- Date: 2018
- Subjects: Nanotubes , Rubber chemistry Nanocomposites (Materials) Nanostructured materials
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/23393 , vital:30538
- Description: The recent advancement in the field of nano-technology has raised much interest in the area of natural rubber latex (NRL) processing. This interest stems from the exceptional properties of nano-material and the promising results obtained by several researchers. Studies have shown that very low loadings of inorganic nanomaterials such as carbon nanotube (CNT) in NRL matrix leads to enhanced tensile strength, tensile modulus, tear resistance and aberration resistance. Thus providing a great prospect for reinforcement of thin film NRL articles such as condom. In this research, prevulcanised natural rubber latex (PvNRL) composite blends containing single walled carbon nanotubes (SWCNTs) were prepared via direct mixing. A progressive discolouration of PvNRL was observed with increased loadings of CNTs. Thermal analysis revealed faster drying rates for the composite blends containing SWCNT. Results from equilibrium swelling experiments also suggested a slight increase in crosslink density in the presence of SWCNT. There was a significant influence on flow behaviour of PvNRL as a result of varying loadings of SWCNT suspension. This was reflected as a change in pseudoplasticity and apparent viscosity. For Instance, apparent viscosity at a shear rate of 1 s-1 at 25°C for PvNRL with ~0.08% SWCNT was 2.5 Pa.s, compared to 0.49 Pa.s for the blends with 0.02% SWCNT. Condoms were moulded via the straight dipping technique using custom made glass formers. A series of dilutions was performed to correct the viscosity differences. This also ensured good consistency and promoted uniform deposition of PvNRL on the glass former. The average dimensions of the condoms produced in terms of length and width were ~191.17 ± 5.17 mm and 52.67 ± 5.17 mm respectively. Thickness measurement varied slightly according to the method of determination. The water leakage test suggested the absence of holes in the condoms produced. However, results from electrical leakage test contradicted those from water leak test. The results from infrared spectroscopy (FTIR) did not confirm the presence of chemical interactions between the SWCNT and PvNRL matrix. Glass transition temperature (Tg) was also unaffected across the blends. The stiffness (or modulus) was unaffected in all the condoms, as revealed by results from indentation hardness analysis. The SWCNT showed no significant influence on thermal decomposition temperatures of the condoms. Nonetheless, images from optical microscopy revealed increased surface roughness corresponding to higher loadings of SWCNT. Results from stress relaxation studies revealed improved retention of modulus under constant strain for condom samples containing SWCNT.
- Full Text:
- Date Issued: 2018
- Authors: Agbakoba, Victor Chike
- Date: 2018
- Subjects: Nanotubes , Rubber chemistry Nanocomposites (Materials) Nanostructured materials
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/23393 , vital:30538
- Description: The recent advancement in the field of nano-technology has raised much interest in the area of natural rubber latex (NRL) processing. This interest stems from the exceptional properties of nano-material and the promising results obtained by several researchers. Studies have shown that very low loadings of inorganic nanomaterials such as carbon nanotube (CNT) in NRL matrix leads to enhanced tensile strength, tensile modulus, tear resistance and aberration resistance. Thus providing a great prospect for reinforcement of thin film NRL articles such as condom. In this research, prevulcanised natural rubber latex (PvNRL) composite blends containing single walled carbon nanotubes (SWCNTs) were prepared via direct mixing. A progressive discolouration of PvNRL was observed with increased loadings of CNTs. Thermal analysis revealed faster drying rates for the composite blends containing SWCNT. Results from equilibrium swelling experiments also suggested a slight increase in crosslink density in the presence of SWCNT. There was a significant influence on flow behaviour of PvNRL as a result of varying loadings of SWCNT suspension. This was reflected as a change in pseudoplasticity and apparent viscosity. For Instance, apparent viscosity at a shear rate of 1 s-1 at 25°C for PvNRL with ~0.08% SWCNT was 2.5 Pa.s, compared to 0.49 Pa.s for the blends with 0.02% SWCNT. Condoms were moulded via the straight dipping technique using custom made glass formers. A series of dilutions was performed to correct the viscosity differences. This also ensured good consistency and promoted uniform deposition of PvNRL on the glass former. The average dimensions of the condoms produced in terms of length and width were ~191.17 ± 5.17 mm and 52.67 ± 5.17 mm respectively. Thickness measurement varied slightly according to the method of determination. The water leakage test suggested the absence of holes in the condoms produced. However, results from electrical leakage test contradicted those from water leak test. The results from infrared spectroscopy (FTIR) did not confirm the presence of chemical interactions between the SWCNT and PvNRL matrix. Glass transition temperature (Tg) was also unaffected across the blends. The stiffness (or modulus) was unaffected in all the condoms, as revealed by results from indentation hardness analysis. The SWCNT showed no significant influence on thermal decomposition temperatures of the condoms. Nonetheless, images from optical microscopy revealed increased surface roughness corresponding to higher loadings of SWCNT. Results from stress relaxation studies revealed improved retention of modulus under constant strain for condom samples containing SWCNT.
- Full Text:
- Date Issued: 2018
Practical application of distributed ledger technology in support of digital evidence integrity verification processes
- Authors: Weilbach, William Thomas
- Date: 2018
- Subjects: Digital forensic science , Blockchains (Databases) , Bitcoin , Distributed databases , Computer systems Verification
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61872 , vital:28070
- Description: After its birth in cryptocurrencies, distributed ledger (blockchain) technology rapidly grew in popularity in other technology domains. Alternative applications of this technology range from digitizing the bank guarantees process for commercial property leases (Anz and IBM, 2017) to tracking the provenance of high-value physical goods (Everledger Ltd., 2017). As a whole, distributed ledger technology has acted as a catalyst to the rise of many innovative alternative solutions to existing problems, mostly associated with trust and integrity. In this research, a niche application of this technology is proposed for use in digital forensics by providing a mechanism for the transparent and irrefutable verification of digital evidence, ensuring its integrity as established blockchains serve as an ideal mechanism to store and validate arbitrary data against. Evaluation and identification of candidate technologies in this domain is based on a set of requirements derived from previous work in this field (Weilbach, 2014). OpenTimestamps (Todd, 2016b) is chosen as the foundation of further work for its robust architecture, transparent nature and multi-platform support. A robust evaluation and discussion of OpenTimestamps is performed to reinforce why it can be trusted as an implementation and protocol. An implementation of OpenTimestamps is designed for the popular open source forensic tool, Autopsy, and an Autopsy module is subsequently developed and released to the public. OpenTimestamps is tested at scale and found to have insignificant error rates for the verification of timestamps. Through practical implementation and extensive testing, it is shown that OpenTimestamps has the potential to significantly advance the practice of digital evidence integrity verification. A conclusion is reached by discussing some of the limitations of OpenTimestamps in terms of accuracy and error rates. It is shown that although OpenTimestamps has very specific timing claims in the attestation, with a near zero error rate, the actual attestation is truly accurate to within a day. This is followed by proposing potential avenues for future work.
- Full Text:
- Date Issued: 2018
- Authors: Weilbach, William Thomas
- Date: 2018
- Subjects: Digital forensic science , Blockchains (Databases) , Bitcoin , Distributed databases , Computer systems Verification
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/61872 , vital:28070
- Description: After its birth in cryptocurrencies, distributed ledger (blockchain) technology rapidly grew in popularity in other technology domains. Alternative applications of this technology range from digitizing the bank guarantees process for commercial property leases (Anz and IBM, 2017) to tracking the provenance of high-value physical goods (Everledger Ltd., 2017). As a whole, distributed ledger technology has acted as a catalyst to the rise of many innovative alternative solutions to existing problems, mostly associated with trust and integrity. In this research, a niche application of this technology is proposed for use in digital forensics by providing a mechanism for the transparent and irrefutable verification of digital evidence, ensuring its integrity as established blockchains serve as an ideal mechanism to store and validate arbitrary data against. Evaluation and identification of candidate technologies in this domain is based on a set of requirements derived from previous work in this field (Weilbach, 2014). OpenTimestamps (Todd, 2016b) is chosen as the foundation of further work for its robust architecture, transparent nature and multi-platform support. A robust evaluation and discussion of OpenTimestamps is performed to reinforce why it can be trusted as an implementation and protocol. An implementation of OpenTimestamps is designed for the popular open source forensic tool, Autopsy, and an Autopsy module is subsequently developed and released to the public. OpenTimestamps is tested at scale and found to have insignificant error rates for the verification of timestamps. Through practical implementation and extensive testing, it is shown that OpenTimestamps has the potential to significantly advance the practice of digital evidence integrity verification. A conclusion is reached by discussing some of the limitations of OpenTimestamps in terms of accuracy and error rates. It is shown that although OpenTimestamps has very specific timing claims in the attestation, with a near zero error rate, the actual attestation is truly accurate to within a day. This is followed by proposing potential avenues for future work.
- Full Text:
- Date Issued: 2018
Practice intentions at entry to and exit from medical schools aspiring to social accountability: findings from the Training for Health Equity Network Graduate Outcome Study
- Iputo, Jehu, Sarah Larkins , Karen Johnston, John C. Hogenbirk, Sara Willems, Salwa Elsanousi, Marykutty Mammen, Kaatje Van Roy, Jehu Iputo , Fortunato L. Cristobal , Jennene Greenhill, Charlie Labarda11 and Andre-Jacques Neusy
- Authors: Iputo, Jehu , Sarah Larkins , Karen Johnston, John C. Hogenbirk, Sara Willems, Salwa Elsanousi, Marykutty Mammen, Kaatje Van Roy, Jehu Iputo , Fortunato L. Cristobal , Jennene Greenhill, Charlie Labarda11 and Andre-Jacques Neusy
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5415 , vital:44567 , https://pubmed.ncbi.nlm.nih.gov/30424760/
- Description: Background: Understanding the impact of selection and medical education on practice intentions and eventual practice is an essential component of training a fit-for-purpose health workforce distributed according to population need. Existing evidence comes largely from high-income settings and neglects contextual factors. This paper describes the practice intentions of entry and exit cohorts of medical students across low and high income settings and the correlation of student characteristics with these intentions. Methods: The Training for Health Equity Network (THEnet) Graduate Outcome Study (GOS) is an international prospective cohort study tracking learners throughout training and ten years into practice as part of the longitudinal impact assessment described in THEnet’s Evaluation Framework. THEnet is an international community of practice of twelve medical schools with a social accountability mandate. Data presented here include cross-sectional entry and exit data obtained from different cohorts of medical students involving eight medical schools in six countries and five continents. Binary logistic regression was used to create adjusted odds ratios for associations with practice intent. Results: Findings from 3346 learners from eight THEnet medical schools in 6 countries collected between 2012 and 2016 are presented. A high proportion of study respondents at these schools come from rural and disadvantaged backgrounds and these respondents are more likely than others to express an intention to work in underserved locations after graduation at both entry and exit from medical school. After adjusting for confounding factors, rural and low income background and regional location of medical school were the most important predictors of intent to practice in a rural location. For schools in the Philippines and Africa, intention to emigrate was more likely for respondents from high income and urban backgrounds.
- Full Text:
- Date Issued: 2018
- Authors: Iputo, Jehu , Sarah Larkins , Karen Johnston, John C. Hogenbirk, Sara Willems, Salwa Elsanousi, Marykutty Mammen, Kaatje Van Roy, Jehu Iputo , Fortunato L. Cristobal , Jennene Greenhill, Charlie Labarda11 and Andre-Jacques Neusy
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5415 , vital:44567 , https://pubmed.ncbi.nlm.nih.gov/30424760/
- Description: Background: Understanding the impact of selection and medical education on practice intentions and eventual practice is an essential component of training a fit-for-purpose health workforce distributed according to population need. Existing evidence comes largely from high-income settings and neglects contextual factors. This paper describes the practice intentions of entry and exit cohorts of medical students across low and high income settings and the correlation of student characteristics with these intentions. Methods: The Training for Health Equity Network (THEnet) Graduate Outcome Study (GOS) is an international prospective cohort study tracking learners throughout training and ten years into practice as part of the longitudinal impact assessment described in THEnet’s Evaluation Framework. THEnet is an international community of practice of twelve medical schools with a social accountability mandate. Data presented here include cross-sectional entry and exit data obtained from different cohorts of medical students involving eight medical schools in six countries and five continents. Binary logistic regression was used to create adjusted odds ratios for associations with practice intent. Results: Findings from 3346 learners from eight THEnet medical schools in 6 countries collected between 2012 and 2016 are presented. A high proportion of study respondents at these schools come from rural and disadvantaged backgrounds and these respondents are more likely than others to express an intention to work in underserved locations after graduation at both entry and exit from medical school. After adjusting for confounding factors, rural and low income background and regional location of medical school were the most important predictors of intent to practice in a rural location. For schools in the Philippines and Africa, intention to emigrate was more likely for respondents from high income and urban backgrounds.
- Full Text:
- Date Issued: 2018
Practising Adaptive IWRM (Integrated Water Resources Management) in South Africa
- Palmer, Carolyn G, Munnik, Victor, du Toit, Derick, Rogers, Kevin H, Pollard, Sharon, Hamer, Nick, Weaver, Matthew J T, Retief, Hugo, Sahula, Asiphe, O’Keeffe, Jay H
- Authors: Palmer, Carolyn G , Munnik, Victor , du Toit, Derick , Rogers, Kevin H , Pollard, Sharon , Hamer, Nick , Weaver, Matthew J T , Retief, Hugo , Sahula, Asiphe , O’Keeffe, Jay H
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438005 , vital:73428 , ISBN 978-1-4312-0983-5 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2248-1-18.pdf
- Description: This chapter serves as a general introduction to the TPNP case stud-ies, with feedback from the progress of the RESILIM-O project. We draw attention here, and note clearly, that each case is set in a different context and scale, and proceeded in different ways, as well as combin-ing in use different discourses/practices and methodologies. To ensure a basis for comparability, each case study was required to use the Adaptive IWRM approach and methodologies, while not being required to record results in the same format. Case studies were designed to enable an exploration of scale effects–a core theoretical concept in complex social-ecological systems. We will be in a position to write a scholarly paper on a scale-comparison of practice-based Adaptive IWRM learning at different spatial and governance (institutional and social) scales, as a result of these findings.
- Full Text:
- Date Issued: 2018
- Authors: Palmer, Carolyn G , Munnik, Victor , du Toit, Derick , Rogers, Kevin H , Pollard, Sharon , Hamer, Nick , Weaver, Matthew J T , Retief, Hugo , Sahula, Asiphe , O’Keeffe, Jay H
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438005 , vital:73428 , ISBN 978-1-4312-0983-5 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/2248-1-18.pdf
- Description: This chapter serves as a general introduction to the TPNP case stud-ies, with feedback from the progress of the RESILIM-O project. We draw attention here, and note clearly, that each case is set in a different context and scale, and proceeded in different ways, as well as combin-ing in use different discourses/practices and methodologies. To ensure a basis for comparability, each case study was required to use the Adaptive IWRM approach and methodologies, while not being required to record results in the same format. Case studies were designed to enable an exploration of scale effects–a core theoretical concept in complex social-ecological systems. We will be in a position to write a scholarly paper on a scale-comparison of practice-based Adaptive IWRM learning at different spatial and governance (institutional and social) scales, as a result of these findings.
- Full Text:
- Date Issued: 2018
Pre-service education students’ application of visualisation strategies to solve mathematical word-problems
- Authors: Shaw , Peter
- Date: 2018
- Subjects: Mathematics -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , PhD (Education)
- Identifier: http://hdl.handle.net/10353/12941 , vital:39406
- Description: This classroom-based action research dissertation examined visualisation strategies used by pre-service Intermediate Phase PGCE education students to solve mathematical word-problems. The setting was an Eastern Cape university. Previous literature indicated a positive correlation between the use of visual scaffolds and success in solving word problems. However, a gap was found insofar as little research had been published on the application of visualisation to word-problems by student teachers in South Africa. This thesis advances our understanding of the role visualisation may play in assisting student teachers to solve word-problems. The theoretic framework was informed by Bruner’s theory of learning. The research was grounded in the hermeneutic tradition. An interpretivist research paradigm was expedited by using an inductive, naturalistic perspective and relativist ontology. Thirtyeight student-teachers participated in the study. Parallel and convergent qualitative and quantitative data gathering instruments were used, thereby facilitating triangulation and examination for microgenesis. It was found that vestiges of past teaching practices initially limited the participants’ knowledge to a deeply-flawed, banking model of routines and an instrumental perception of mathematics. Disruptive calls for social justice impeded progress. Albeit visualisation strategies liberated understanding, many foundational concepts and skills had to be reconstructed. The confluence of time and rehearsal culminated in some measure of expertise. Sustained effort enabled new knowledge to be compressed and consigned to long-term memory. Salient visual representations assisted participants to conceptualise relational mathematical metaconcepts and reduced the cognitive demands imposed by word-problems but that achievement was a hard-won prize.
- Full Text:
- Date Issued: 2018
- Authors: Shaw , Peter
- Date: 2018
- Subjects: Mathematics -- Study and teaching
- Language: English
- Type: Thesis , Doctoral , PhD (Education)
- Identifier: http://hdl.handle.net/10353/12941 , vital:39406
- Description: This classroom-based action research dissertation examined visualisation strategies used by pre-service Intermediate Phase PGCE education students to solve mathematical word-problems. The setting was an Eastern Cape university. Previous literature indicated a positive correlation between the use of visual scaffolds and success in solving word problems. However, a gap was found insofar as little research had been published on the application of visualisation to word-problems by student teachers in South Africa. This thesis advances our understanding of the role visualisation may play in assisting student teachers to solve word-problems. The theoretic framework was informed by Bruner’s theory of learning. The research was grounded in the hermeneutic tradition. An interpretivist research paradigm was expedited by using an inductive, naturalistic perspective and relativist ontology. Thirtyeight student-teachers participated in the study. Parallel and convergent qualitative and quantitative data gathering instruments were used, thereby facilitating triangulation and examination for microgenesis. It was found that vestiges of past teaching practices initially limited the participants’ knowledge to a deeply-flawed, banking model of routines and an instrumental perception of mathematics. Disruptive calls for social justice impeded progress. Albeit visualisation strategies liberated understanding, many foundational concepts and skills had to be reconstructed. The confluence of time and rehearsal culminated in some measure of expertise. Sustained effort enabled new knowledge to be compressed and consigned to long-term memory. Salient visual representations assisted participants to conceptualise relational mathematical metaconcepts and reduced the cognitive demands imposed by word-problems but that achievement was a hard-won prize.
- Full Text:
- Date Issued: 2018
Predicting reintroduction outcomes: assessing the feasibility of reintroducing African wild dog to a small protected area
- Authors: Vogel, John Thomas
- Date: 2018
- Subjects: African wild dog , Wild dogs -- South Africa Wild dogs -- Conservation -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/36464 , vital:33947
- Description: Large mammalian carnivores have experienced significant contractions in population sizes and geographical ranges. The conservation of large carnivores is crucially important, particularly due to their vulnerability to extinction and their functional significance and ability to structure ecosystems. Due to an expanding human footprint, large carnivores are increasingly subject to modified and spatially constrained habitats. A growing debate exists as to how to conserve and coexist with large carnivores in an anthropogenically induced environment. Reintroduction, as a conservation tool to restore locally extirpated large carnivores to portions of their former ranges is increasingly being applied. However, in South Africa, habitat to support large carnivores remain small and non-contiguous. Food is a fundamental ecological requirement to sustain reintroduced large carnivores. Therefore, an understanding of large predator foraging patterns can be informative in the context of how the predator species influences and utilises a novel ecosystem. We investigated the foraging behaviour of reintroduced African wild dog (Lycaon pictus) at five small protected areas in KwaZulu-Natal, South Africa. Wild dog utilised 16 prey species, albeit they primarily used nyala (Tragelaphus angasii) and impala (Aepyceros melampus) which collectively form 75 % of their diet. Only nyala was significantly preferred, suggesting that this prey species is used in greater proportion to their abundance. As wild dogs are social cooperative hunters, we tested whether wild dog pack size was correlated to prey mass selection. There was no evidence to suggest that larger packs use larger prey. However, the mean wild dog pack size in our sample sites, was relatively smaller than those encountered elsewhere. Furthermore, wild dog have been shown to modify their hunting behaviour in the presence of wildlife-proof fencing, by using fences to aid in the capture of larger prey species than would innately occur. We compared the prey mass of wild dog kills in relation to proximity of these hard boundaries. Despite the affinity towards kills occurring within 200 m of fences, the upward bias caused by fences on prey mass selection was inconsistent across sample sites. The relatively small size of wild dogs makes them particularly vulnerable to competition. As the energetic output of wild dog is high, interspecific competition can increase foraging costs. The reintroduction of large carnivores to small artificially induced systems may be a contentious issue as resources available to support large carnivores are expected to be relatively more finite. We compared both the potential inter- and intraspecific dietary niche dimensions of an intact large carnivore guild in context of a wild dog reintroduction. We determined cheetah (Acinonyx jubatus), leopard (Panthera pardus), and lion (Panthera leo) prey composition, diet breadth, overlap, prey preference and predicted the density of an intact large carnivore guild in a novel landscape. Further, we compared the foraging behaviour of these large carnivores to that of wild dog. Our findings suggest that large African carnivores in small protected areas are subject to a considerable dietary niche overlap. Wild dog and cheetah, particularly reproductive females with dependent offspring, displayed the greatest potential for dietary overlap and subsequent competition. Leopard and lion at the population species level exhibited greater degrees of foraging plasticity. Lion displayed a contrasting prey species preference to sympatric predators as they selected for prey items frequently avoided by cheetah, leopard and wild dog. The proposed wild dog reintroduction site is expected to sustain seven wild dog based on the availability of preferred prey biomass. However, the reintroduction of wild dog to the small protected area is expected to have negative lateral trophic influences on other species of conservation concern. This should be of vital importance to management of the protected area. As the influence of competition in food-web and population dynamics, particularly in resource poor environments may be profound, our research highlights the need to assess the influence of competitive forces in structuring and restoring large predators to portions of their historical range.
- Full Text:
- Date Issued: 2018
- Authors: Vogel, John Thomas
- Date: 2018
- Subjects: African wild dog , Wild dogs -- South Africa Wild dogs -- Conservation -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/36464 , vital:33947
- Description: Large mammalian carnivores have experienced significant contractions in population sizes and geographical ranges. The conservation of large carnivores is crucially important, particularly due to their vulnerability to extinction and their functional significance and ability to structure ecosystems. Due to an expanding human footprint, large carnivores are increasingly subject to modified and spatially constrained habitats. A growing debate exists as to how to conserve and coexist with large carnivores in an anthropogenically induced environment. Reintroduction, as a conservation tool to restore locally extirpated large carnivores to portions of their former ranges is increasingly being applied. However, in South Africa, habitat to support large carnivores remain small and non-contiguous. Food is a fundamental ecological requirement to sustain reintroduced large carnivores. Therefore, an understanding of large predator foraging patterns can be informative in the context of how the predator species influences and utilises a novel ecosystem. We investigated the foraging behaviour of reintroduced African wild dog (Lycaon pictus) at five small protected areas in KwaZulu-Natal, South Africa. Wild dog utilised 16 prey species, albeit they primarily used nyala (Tragelaphus angasii) and impala (Aepyceros melampus) which collectively form 75 % of their diet. Only nyala was significantly preferred, suggesting that this prey species is used in greater proportion to their abundance. As wild dogs are social cooperative hunters, we tested whether wild dog pack size was correlated to prey mass selection. There was no evidence to suggest that larger packs use larger prey. However, the mean wild dog pack size in our sample sites, was relatively smaller than those encountered elsewhere. Furthermore, wild dog have been shown to modify their hunting behaviour in the presence of wildlife-proof fencing, by using fences to aid in the capture of larger prey species than would innately occur. We compared the prey mass of wild dog kills in relation to proximity of these hard boundaries. Despite the affinity towards kills occurring within 200 m of fences, the upward bias caused by fences on prey mass selection was inconsistent across sample sites. The relatively small size of wild dogs makes them particularly vulnerable to competition. As the energetic output of wild dog is high, interspecific competition can increase foraging costs. The reintroduction of large carnivores to small artificially induced systems may be a contentious issue as resources available to support large carnivores are expected to be relatively more finite. We compared both the potential inter- and intraspecific dietary niche dimensions of an intact large carnivore guild in context of a wild dog reintroduction. We determined cheetah (Acinonyx jubatus), leopard (Panthera pardus), and lion (Panthera leo) prey composition, diet breadth, overlap, prey preference and predicted the density of an intact large carnivore guild in a novel landscape. Further, we compared the foraging behaviour of these large carnivores to that of wild dog. Our findings suggest that large African carnivores in small protected areas are subject to a considerable dietary niche overlap. Wild dog and cheetah, particularly reproductive females with dependent offspring, displayed the greatest potential for dietary overlap and subsequent competition. Leopard and lion at the population species level exhibited greater degrees of foraging plasticity. Lion displayed a contrasting prey species preference to sympatric predators as they selected for prey items frequently avoided by cheetah, leopard and wild dog. The proposed wild dog reintroduction site is expected to sustain seven wild dog based on the availability of preferred prey biomass. However, the reintroduction of wild dog to the small protected area is expected to have negative lateral trophic influences on other species of conservation concern. This should be of vital importance to management of the protected area. As the influence of competition in food-web and population dynamics, particularly in resource poor environments may be profound, our research highlights the need to assess the influence of competitive forces in structuring and restoring large predators to portions of their historical range.
- Full Text:
- Date Issued: 2018
Pregnant women’s construction of social support from their intimate partners during pregnancy
- Authors: Bottoman, Phathiswa Esona
- Date: 2018
- Subjects: Pregnant women -- South Africa -- Eastern Cape -- Relations with men Pregnancy -- Psychological aspects Pregnant women -- Social conditions
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/62560 , vital:28207
- Description: There is a growing body of research aimed at understanding social support during pregnancy in South Africa. Pregnancy is constantly referred to as one of the challenging and stressful periods affecting women’s physical and psychological well-being. Various research studies on social support argue that social support is paramount at this stage. Research on social support indicates that having adequate and quality social support impacts on how pregnant women experience pregnancy. My interest in social support comes in the wake of absent fathers in South Africa and with the emerging trend of “new” fathers. Although there is a volume of research on social support, it tends to be realist. Using a social constructionist framework, I explore other ways of talking about social support in an attempt to expand the discourse around social support. I explore how pregnant women talk about social support during pregnancy from their intimate partners in the small rural municipality of Elundini, Eastern Cape, South Africa. Intimate partner support was limited to heterosexual partners regardless of their marital status. The sampling procedure followed a non-probability sampling method. Participants of the study were between 24 and 32 years old. Their gestational age ranged between five and eight months. Fourteen in-depth interviews using photo-elicitation were conducted with seven participants and were analysed using a social constructionist informed thematic analysis. The major theme that emerged from the analysis was partner involvement and absence during pregnancy. The analysis of results suggests that expectant father presence translates to social support. Participants constructed his presence as reassurance in the context of possible abandonment. Absence was constructed in different ways: participants constructed absence as unjust and unfair, absence and marriage, temporary absence in the form of cultural phenomenon of ukwaliswa/ukubukubazana, absence as normal but burdening to the pregnant women’s social network. Participants reported that social support from the expectant father affected pregnancy wantedness.
- Full Text:
- Date Issued: 2018
- Authors: Bottoman, Phathiswa Esona
- Date: 2018
- Subjects: Pregnant women -- South Africa -- Eastern Cape -- Relations with men Pregnancy -- Psychological aspects Pregnant women -- Social conditions
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/62560 , vital:28207
- Description: There is a growing body of research aimed at understanding social support during pregnancy in South Africa. Pregnancy is constantly referred to as one of the challenging and stressful periods affecting women’s physical and psychological well-being. Various research studies on social support argue that social support is paramount at this stage. Research on social support indicates that having adequate and quality social support impacts on how pregnant women experience pregnancy. My interest in social support comes in the wake of absent fathers in South Africa and with the emerging trend of “new” fathers. Although there is a volume of research on social support, it tends to be realist. Using a social constructionist framework, I explore other ways of talking about social support in an attempt to expand the discourse around social support. I explore how pregnant women talk about social support during pregnancy from their intimate partners in the small rural municipality of Elundini, Eastern Cape, South Africa. Intimate partner support was limited to heterosexual partners regardless of their marital status. The sampling procedure followed a non-probability sampling method. Participants of the study were between 24 and 32 years old. Their gestational age ranged between five and eight months. Fourteen in-depth interviews using photo-elicitation were conducted with seven participants and were analysed using a social constructionist informed thematic analysis. The major theme that emerged from the analysis was partner involvement and absence during pregnancy. The analysis of results suggests that expectant father presence translates to social support. Participants constructed his presence as reassurance in the context of possible abandonment. Absence was constructed in different ways: participants constructed absence as unjust and unfair, absence and marriage, temporary absence in the form of cultural phenomenon of ukwaliswa/ukubukubazana, absence as normal but burdening to the pregnant women’s social network. Participants reported that social support from the expectant father affected pregnancy wantedness.
- Full Text:
- Date Issued: 2018
Preimages for SHA-1
- Authors: Motara, Yusuf Moosa
- Date: 2018
- Subjects: Data encryption (Computer science) , Computer security -- Software , Hashing (Computer science) , Data compression (Computer science) , Preimage , Secure Hash Algorithm 1 (SHA-1)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/57885 , vital:27004
- Description: This research explores the problem of finding a preimage — an input that, when passed through a particular function, will result in a pre-specified output — for the compression function of the SHA-1 cryptographic hash. This problem is much more difficult than the problem of finding a collision for a hash function, and preimage attacks for very few popular hash functions are known. The research begins by introducing the field and giving an overview of the existing work in the area. A thorough analysis of the compression function is made, resulting in alternative formulations for both parts of the function, and both statistical and theoretical tools to determine the difficulty of the SHA-1 preimage problem. Different representations (And- Inverter Graph, Binary Decision Diagram, Conjunctive Normal Form, Constraint Satisfaction form, and Disjunctive Normal Form) and associated tools to manipulate and/or analyse these representations are then applied and explored, and results are collected and interpreted. In conclusion, the SHA-1 preimage problem remains unsolved and insoluble for the foreseeable future. The primary issue is one of efficient representation; despite a promising theoretical difficulty, both the diffusion characteristics and the depth of the tree stand in the way of efficient search. Despite this, the research served to confirm and quantify the difficulty of the problem both theoretically, using Schaefer's Theorem, and practically, in the context of different representations.
- Full Text:
- Date Issued: 2018
- Authors: Motara, Yusuf Moosa
- Date: 2018
- Subjects: Data encryption (Computer science) , Computer security -- Software , Hashing (Computer science) , Data compression (Computer science) , Preimage , Secure Hash Algorithm 1 (SHA-1)
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/57885 , vital:27004
- Description: This research explores the problem of finding a preimage — an input that, when passed through a particular function, will result in a pre-specified output — for the compression function of the SHA-1 cryptographic hash. This problem is much more difficult than the problem of finding a collision for a hash function, and preimage attacks for very few popular hash functions are known. The research begins by introducing the field and giving an overview of the existing work in the area. A thorough analysis of the compression function is made, resulting in alternative formulations for both parts of the function, and both statistical and theoretical tools to determine the difficulty of the SHA-1 preimage problem. Different representations (And- Inverter Graph, Binary Decision Diagram, Conjunctive Normal Form, Constraint Satisfaction form, and Disjunctive Normal Form) and associated tools to manipulate and/or analyse these representations are then applied and explored, and results are collected and interpreted. In conclusion, the SHA-1 preimage problem remains unsolved and insoluble for the foreseeable future. The primary issue is one of efficient representation; despite a promising theoretical difficulty, both the diffusion characteristics and the depth of the tree stand in the way of efficient search. Despite this, the research served to confirm and quantify the difficulty of the problem both theoretically, using Schaefer's Theorem, and practically, in the context of different representations.
- Full Text:
- Date Issued: 2018
Preparation, characterization and in vitro analysis of polyamidoamine drug conjugates containing ferrocene and platinum analogues
- Authors: Mugogodi, Ansley
- Date: 2018
- Subjects: Ferrocene
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/10145 , vital:35360
- Description: Polyamidoamine drug conjugates were prepared from analogues of ferrocene and platinum. Standard reaction procedures were followed in the synthesis of platinum and ferrocene analogues. Michael addition reaction of amines to the activated double bonds of methylenebisacrylamide was applied for preparation of the water soluble polyamidoamine carriers onto which drug analogues were attached. The drug release studies of the conjugates were evaluated at different pH environments. The results obtained from drug release studies showed that rate of drug release was variable depending on the conjugate and pH environment. Mathematical drug release models by Korsmeyer-Peppas were used to determine the drug release characteristics of the ferrocene and platinum based drugs from polyamidoamine drug conjugates. Cytotoxicity potential of the analogues and polyamidoamine drug conjugates was tested on selected cell lines. Cisplatin was used as the standard for comparison of the IC50 values obtained for the compounds tested for cytotoxicity activity. The results from six polymer drug conjugates tested for cytotoxicity activity showed that conjugation of analogues to polyamidoamine carrier enhanced the activity of the analogues in some of the polyamidoamine drug conjugates. Various techniques such as Fourier Transform Infrared (FTIR) spectroscopy, Proton Nuclear Magnetic Resonance spectroscopy (1H NMR), Scanning Electron Microscopy (SEM), transmission electron microscopy (TEM), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray (EDX) spectroscopy were employed for the characterization of the ferrocene and platinum analogues, polyamidoamine carriers and drug conjugates.
- Full Text:
- Date Issued: 2018
- Authors: Mugogodi, Ansley
- Date: 2018
- Subjects: Ferrocene
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/10145 , vital:35360
- Description: Polyamidoamine drug conjugates were prepared from analogues of ferrocene and platinum. Standard reaction procedures were followed in the synthesis of platinum and ferrocene analogues. Michael addition reaction of amines to the activated double bonds of methylenebisacrylamide was applied for preparation of the water soluble polyamidoamine carriers onto which drug analogues were attached. The drug release studies of the conjugates were evaluated at different pH environments. The results obtained from drug release studies showed that rate of drug release was variable depending on the conjugate and pH environment. Mathematical drug release models by Korsmeyer-Peppas were used to determine the drug release characteristics of the ferrocene and platinum based drugs from polyamidoamine drug conjugates. Cytotoxicity potential of the analogues and polyamidoamine drug conjugates was tested on selected cell lines. Cisplatin was used as the standard for comparison of the IC50 values obtained for the compounds tested for cytotoxicity activity. The results from six polymer drug conjugates tested for cytotoxicity activity showed that conjugation of analogues to polyamidoamine carrier enhanced the activity of the analogues in some of the polyamidoamine drug conjugates. Various techniques such as Fourier Transform Infrared (FTIR) spectroscopy, Proton Nuclear Magnetic Resonance spectroscopy (1H NMR), Scanning Electron Microscopy (SEM), transmission electron microscopy (TEM), Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray (EDX) spectroscopy were employed for the characterization of the ferrocene and platinum analogues, polyamidoamine carriers and drug conjugates.
- Full Text:
- Date Issued: 2018
Presence of microplastics in the tube structure of the reef-building polychaete Gunnarea gaimardi (Quatrefages 1848)
- Nel, Holly A, Froneman, P William
- Authors: Nel, Holly A , Froneman, P William
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/479330 , vital:78287 , https://doi.org/10.2989/1814232X.2018.1443835
- Description: The prevalence of microplastics in the marine environment has resulted in a need to understand their association with various fauna. The aim of this study was to assess whether microplastic particles are present in the tube structure of the indigenous reef-building polychaete Gunnarea gaimardi, which occurs along the coast of South Africa. Sampling was conducted at nine stations along the west and southeast coastlines of South Africa, in July 2016 and April/May 2017. Microplastic particles were recorded in all tube structures of G. gaimardi, with the density ranging between 0.056 and 1.113 microplastic particles g–1 dry weight (dwt). There were no significant differences between sites (p > 0.05), resulting in an overall average of 0.275 (SD 0.215) microplastic particles g–1 (dwt). To the authors’ knowledge, this is the first study to show that synthetic polymers are found in the tubes of reef-building polychaetes along the coast of South Africa.
- Full Text:
- Date Issued: 2018
- Authors: Nel, Holly A , Froneman, P William
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/479330 , vital:78287 , https://doi.org/10.2989/1814232X.2018.1443835
- Description: The prevalence of microplastics in the marine environment has resulted in a need to understand their association with various fauna. The aim of this study was to assess whether microplastic particles are present in the tube structure of the indigenous reef-building polychaete Gunnarea gaimardi, which occurs along the coast of South Africa. Sampling was conducted at nine stations along the west and southeast coastlines of South Africa, in July 2016 and April/May 2017. Microplastic particles were recorded in all tube structures of G. gaimardi, with the density ranging between 0.056 and 1.113 microplastic particles g–1 dry weight (dwt). There were no significant differences between sites (p > 0.05), resulting in an overall average of 0.275 (SD 0.215) microplastic particles g–1 (dwt). To the authors’ knowledge, this is the first study to show that synthetic polymers are found in the tubes of reef-building polychaetes along the coast of South Africa.
- Full Text:
- Date Issued: 2018