Hybrid field generator controller for optimised perfomance
- Authors: Moleli, Christopher Teboho
- Date: 2003
- Subjects: Hybrid power systems , Wind turbines , Electric power production
- Language: English
- Type: Thesis , Masters , MTech (Electrical Engineering)
- Identifier: vital:10818 , http://hdl.handle.net/10948/236 , Hybrid power systems , Wind turbines , Electric power production
- Description: Battery charging wind turbines like, Hybrid Field Generator, have become more popular in the growing renewable energy market. With wind energy, voltage and current control is generally provided by means of power electronics. The paper describes the analytical investigation in to control aspects of a hybrid field generator controller for optimized performance. The project objective is about maintaining the generated voltage at 28V through out a generator speed range, between 149 rpm and 598 rpm. The over voltage load, known as dump load, is connected to the control circuit to reduce stress on the bypass transistor for speeds above 598 rpm. Maintaining a stable voltage through out the speed range, between 149rpm and 598rpm, is achieved by employing power electronics techniques. This is done by using power converters and inverters to vary the generator armature excitation levels hence varying its air gap flux density. All these take place during each of the three modes of generator operation, which are: buck, boost and permanent magnet modes. Although the generator controller is power electronics based, it also uses software to optimize its performance. In this case, a PIC16F877 microcontroller development system has been used to test the controller function blocks.
- Full Text:
- Date Issued: 2003
- Authors: Moleli, Christopher Teboho
- Date: 2003
- Subjects: Hybrid power systems , Wind turbines , Electric power production
- Language: English
- Type: Thesis , Masters , MTech (Electrical Engineering)
- Identifier: vital:10818 , http://hdl.handle.net/10948/236 , Hybrid power systems , Wind turbines , Electric power production
- Description: Battery charging wind turbines like, Hybrid Field Generator, have become more popular in the growing renewable energy market. With wind energy, voltage and current control is generally provided by means of power electronics. The paper describes the analytical investigation in to control aspects of a hybrid field generator controller for optimized performance. The project objective is about maintaining the generated voltage at 28V through out a generator speed range, between 149 rpm and 598 rpm. The over voltage load, known as dump load, is connected to the control circuit to reduce stress on the bypass transistor for speeds above 598 rpm. Maintaining a stable voltage through out the speed range, between 149rpm and 598rpm, is achieved by employing power electronics techniques. This is done by using power converters and inverters to vary the generator armature excitation levels hence varying its air gap flux density. All these take place during each of the three modes of generator operation, which are: buck, boost and permanent magnet modes. Although the generator controller is power electronics based, it also uses software to optimize its performance. In this case, a PIC16F877 microcontroller development system has been used to test the controller function blocks.
- Full Text:
- Date Issued: 2003
If you think that multi-media is not for Africa
- Authors: Garman, Brian
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454723 , vital:75370 , https://hdl.handle.net/10520/EJC146246
- Description: Over 20 years ago I sat myself down in front of the first Apple Mac to arrive in our department and far from being excited by it, I can remember thinking "this'll never catch on..."
- Full Text:
- Date Issued: 2003
- Authors: Garman, Brian
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/454723 , vital:75370 , https://hdl.handle.net/10520/EJC146246
- Description: Over 20 years ago I sat myself down in front of the first Apple Mac to arrive in our department and far from being excited by it, I can remember thinking "this'll never catch on..."
- Full Text:
- Date Issued: 2003
Implementing Location Services in the Location-Transparent, Distributed Environment of the Internet
- Clayton, Peter G, Preston, Michael, Wells, George C
- Authors: Clayton, Peter G , Preston, Michael , Wells, George C
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430467 , vital:72693 , https://link.springer.com/book/10.1007/b13582?page=1#toc
- Description: This volume contains the papers presented at the 5th International Workshop on Advanced Parallel Processing Technologies, APPT 2003. This series of workshops is designed to strengthen the cooperation between the German and Chinese institutions active in the area of these technologies. It has continued to grow, providing an excellent forum for reporting advances in parallel processing technologies. The 5th workshop itself addressed the entire gamut of related topics, ranging from the architectural aspects of parallel computer hardware and system software to the applied technologies for novel applica-tions. For this workshop, we received over 191 full submissions from researchers all over the world. All the papers were peer-reviewed in depth and qualitatively graded on their relevance, originality, signi?cance, presentation, and the overall appropriateness for their acceptance. Any concerns raised were discussed in the program com-mittee. The organizing committee did an excellent job in selecting 78 papers (Among them, 21 were short ones) for presentation. In short, the papers included here represent the forefront of research from China, Germany, and the other countries.
- Full Text:
- Date Issued: 2003
- Authors: Clayton, Peter G , Preston, Michael , Wells, George C
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430467 , vital:72693 , https://link.springer.com/book/10.1007/b13582?page=1#toc
- Description: This volume contains the papers presented at the 5th International Workshop on Advanced Parallel Processing Technologies, APPT 2003. This series of workshops is designed to strengthen the cooperation between the German and Chinese institutions active in the area of these technologies. It has continued to grow, providing an excellent forum for reporting advances in parallel processing technologies. The 5th workshop itself addressed the entire gamut of related topics, ranging from the architectural aspects of parallel computer hardware and system software to the applied technologies for novel applica-tions. For this workshop, we received over 191 full submissions from researchers all over the world. All the papers were peer-reviewed in depth and qualitatively graded on their relevance, originality, signi?cance, presentation, and the overall appropriateness for their acceptance. Any concerns raised were discussed in the program com-mittee. The organizing committee did an excellent job in selecting 78 papers (Among them, 21 were short ones) for presentation. In short, the papers included here represent the forefront of research from China, Germany, and the other countries.
- Full Text:
- Date Issued: 2003
Implications of a new 40Ar/ 39Ar age for a basalt flow interbedded with the Etjo Formation, Northeast Namibia
- Marsh, Julian S, Swart, Roger S, Phillips, D
- Authors: Marsh, Julian S , Swart, Roger S , Phillips, D
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150364 , vital:38970 , https://doi.org/10.2113/106.4.281
- Description: A reliable 40Ar/39Ar plateau age of 180 ± 1.2 Ma (1σ) has been obtained for fresh basalt lava interbedded with aeolian Etjo Formation sandstones south-southwest of Grootfontein in northeast Namibia. This indicates that the Early Jurassic Karoo flood basalt sequence extended from Botswana into northeast Namibia at least as far as 18 east and that this may mark the eastern extent of the Early Cretaceous Etendeka Igneous Province.
- Full Text: false
- Date Issued: 2003
- Authors: Marsh, Julian S , Swart, Roger S , Phillips, D
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/150364 , vital:38970 , https://doi.org/10.2113/106.4.281
- Description: A reliable 40Ar/39Ar plateau age of 180 ± 1.2 Ma (1σ) has been obtained for fresh basalt lava interbedded with aeolian Etjo Formation sandstones south-southwest of Grootfontein in northeast Namibia. This indicates that the Early Jurassic Karoo flood basalt sequence extended from Botswana into northeast Namibia at least as far as 18 east and that this may mark the eastern extent of the Early Cretaceous Etendeka Igneous Province.
- Full Text: false
- Date Issued: 2003
In defence of moral objectivity
- Authors: McKaiser, Eusebius
- Date: 2003 , 2013-05-23
- Subjects: Ethics , Objectivity
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2740 , http://hdl.handle.net/10962/d1007599 , Ethics , Objectivity
- Description: This thesis examines the problem of moral objectivity, which is constituted by the ontological, epistemological and motivational challenges. It gradually develops an account of moral objectivity that has the dual function of dealing with the enemies of moral objectivity as well as giving a positive account of what moral objectivity is. It establishes these aims by arguing for the following theses. The first set of arguments show that relativist theories of ethics provide us with no forceful grounds for being sceptical about moral objectivity. The second set of arguments deepens the response to those who are sceptical about moral objectivity. It does so by showing in greater detail how rationality plays a substantive role in our practical deliberation, our notion of agency as well as our reactive attitudes. These arguments provide further reasons why we should have faith in the possibility of developing an adequate account of moral objectivity. The last set of arguments provides the positive account of moral objectivity. This positive account ends with the discussion of a paradigmatic moral fact that gives full expression (to the features of moral objectivity that have been articulated and defended.
- Full Text:
- Date Issued: 2003
- Authors: McKaiser, Eusebius
- Date: 2003 , 2013-05-23
- Subjects: Ethics , Objectivity
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2740 , http://hdl.handle.net/10962/d1007599 , Ethics , Objectivity
- Description: This thesis examines the problem of moral objectivity, which is constituted by the ontological, epistemological and motivational challenges. It gradually develops an account of moral objectivity that has the dual function of dealing with the enemies of moral objectivity as well as giving a positive account of what moral objectivity is. It establishes these aims by arguing for the following theses. The first set of arguments show that relativist theories of ethics provide us with no forceful grounds for being sceptical about moral objectivity. The second set of arguments deepens the response to those who are sceptical about moral objectivity. It does so by showing in greater detail how rationality plays a substantive role in our practical deliberation, our notion of agency as well as our reactive attitudes. These arguments provide further reasons why we should have faith in the possibility of developing an adequate account of moral objectivity. The last set of arguments provides the positive account of moral objectivity. This positive account ends with the discussion of a paradigmatic moral fact that gives full expression (to the features of moral objectivity that have been articulated and defended.
- Full Text:
- Date Issued: 2003
Indomethacin reduces lipid peroxidation in rat brain homogenate by binding Fe2+
- Anoopkumar-Dukie, Shailendra, Lack, Barbara, McPhail, Kerry L, Nyokong, Tebello, Lambat, Zaynab, Maharaj, Deepat, Daya, Santy
- Authors: Anoopkumar-Dukie, Shailendra , Lack, Barbara , McPhail, Kerry L , Nyokong, Tebello , Lambat, Zaynab , Maharaj, Deepat , Daya, Santy
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304763 , vital:58487 , xlink:href="https://doi.org/10.1023/A:1021958016928"
- Description: One of the hallmarks of Alzheimer's disease (AD) is the progressive degeneration of cholinergic neurons in the cerebral cortex and hippocampus. It is generally accepted that this neuronal degeneration is due to free-radical-induced damage. These free radicals attack vital structural components of the neurons. This implies that agents that reduce free radical generation could potentially delay the progression of AD. Free radical generation in the brain is assisted by the presence of iron, required by the Fenton reaction. Thus, agents that reduce iron availability for this reaction could potentially reduce free radical formation. Since non steroidal anti-inflammatory drugs (NSAIDS) have been shown to reduce the severity of AD, we investigated the possible mechanism by which indomethacin could afford neuroprotection. Our results show that indomethacin (1 mM) is able to reduce the iron-induced rise in lipid peroxidation in rat brain homogenates. In addition, our NMR data indicate that indomethacin binds the Fe2+/Fe3+ ion. This was confirmed by a study using UV/Vis spectrophotometry. The results imply that indomethacin provides a neuroprotective effect by binding to iron and thus making it unavailable for free radical production.
- Full Text:
- Date Issued: 2003
- Authors: Anoopkumar-Dukie, Shailendra , Lack, Barbara , McPhail, Kerry L , Nyokong, Tebello , Lambat, Zaynab , Maharaj, Deepat , Daya, Santy
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304763 , vital:58487 , xlink:href="https://doi.org/10.1023/A:1021958016928"
- Description: One of the hallmarks of Alzheimer's disease (AD) is the progressive degeneration of cholinergic neurons in the cerebral cortex and hippocampus. It is generally accepted that this neuronal degeneration is due to free-radical-induced damage. These free radicals attack vital structural components of the neurons. This implies that agents that reduce free radical generation could potentially delay the progression of AD. Free radical generation in the brain is assisted by the presence of iron, required by the Fenton reaction. Thus, agents that reduce iron availability for this reaction could potentially reduce free radical formation. Since non steroidal anti-inflammatory drugs (NSAIDS) have been shown to reduce the severity of AD, we investigated the possible mechanism by which indomethacin could afford neuroprotection. Our results show that indomethacin (1 mM) is able to reduce the iron-induced rise in lipid peroxidation in rat brain homogenates. In addition, our NMR data indicate that indomethacin binds the Fe2+/Fe3+ ion. This was confirmed by a study using UV/Vis spectrophotometry. The results imply that indomethacin provides a neuroprotective effect by binding to iron and thus making it unavailable for free radical production.
- Full Text:
- Date Issued: 2003
Influence of cyclodextrins on the fluorescence, photostability and singlet oxygen quantum yields of zinc phthalocyanine and naphthalocyanine complexes
- Tau, Prudence, Ogunsipe, Abimbola O, Maree, Suzanne, Maree, M David, Nyokong, Tebello
- Authors: Tau, Prudence , Ogunsipe, Abimbola O , Maree, Suzanne , Maree, M David , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304775 , vital:58488 , xlink:href="https://doi.org/10.1142/S1088424603000562"
- Description: The effects of formation of cyclodextrin inclusion complexes on the photochemical and photophysical properties of zinc phthalocyanine (ZnPc) and various peripherally substituted zinc phthalocyanines as well as zinc naphthalocyanine (ZnNPc) are investigated. The cyclodextrins employed were the hydroxypropyl-γ-cyclodextrin and unsubstituted β-cyclodextrin. Job's plots were employed to confirm the stoichiometry of the inclusion complexes and showed 2:1 and 4:1 (cyclodextrin:phthalocyanine) inclusion behavior. The phthalocyanine inclusion complexes showed larger singlet oxygen quantum yield (ϕΔ) values when compared to the free phthalocyanines before inclusion, for complexes 1 (zinc naphthalocyanine), 2 (zinc tetranitrophthalocyanine) and 4 (zinc tetra-tert-butylphenoxyphthalocyanine). The fluorescence quantum yields generally remained unchanged following inclusion.
- Full Text:
- Date Issued: 2003
- Authors: Tau, Prudence , Ogunsipe, Abimbola O , Maree, Suzanne , Maree, M David , Nyokong, Tebello
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304775 , vital:58488 , xlink:href="https://doi.org/10.1142/S1088424603000562"
- Description: The effects of formation of cyclodextrin inclusion complexes on the photochemical and photophysical properties of zinc phthalocyanine (ZnPc) and various peripherally substituted zinc phthalocyanines as well as zinc naphthalocyanine (ZnNPc) are investigated. The cyclodextrins employed were the hydroxypropyl-γ-cyclodextrin and unsubstituted β-cyclodextrin. Job's plots were employed to confirm the stoichiometry of the inclusion complexes and showed 2:1 and 4:1 (cyclodextrin:phthalocyanine) inclusion behavior. The phthalocyanine inclusion complexes showed larger singlet oxygen quantum yield (ϕΔ) values when compared to the free phthalocyanines before inclusion, for complexes 1 (zinc naphthalocyanine), 2 (zinc tetranitrophthalocyanine) and 4 (zinc tetra-tert-butylphenoxyphthalocyanine). The fluorescence quantum yields generally remained unchanged following inclusion.
- Full Text:
- Date Issued: 2003
Insect Pest Management and Ecological Research, G.H. Walter: book review
- Authors: Villet, Martin H
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451735 , vital:75073 , https://hdl.handle.net/10520/EJC32546
- Description: This book is a 275-page argument for the place of theoretical biology in pest management research. Its general message is that contemporary pest management research emphasizes application of technology or strategic research at the expense of application of knowledge or tactical research, and that even the application of knowledge should actually be subservient to the development and extension of knowledge, theoretical research. Whenever we study a pest, we are presented with an opportunity to enhance, rather than merely apply, knowledge. It is argued that pest management research is currently failing itself because it is not doing this, and several areas of theoretical biology are identified as offering ways out of this situation.
- Full Text:
- Date Issued: 2003
- Authors: Villet, Martin H
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/451735 , vital:75073 , https://hdl.handle.net/10520/EJC32546
- Description: This book is a 275-page argument for the place of theoretical biology in pest management research. Its general message is that contemporary pest management research emphasizes application of technology or strategic research at the expense of application of knowledge or tactical research, and that even the application of knowledge should actually be subservient to the development and extension of knowledge, theoretical research. Whenever we study a pest, we are presented with an opportunity to enhance, rather than merely apply, knowledge. It is argued that pest management research is currently failing itself because it is not doing this, and several areas of theoretical biology are identified as offering ways out of this situation.
- Full Text:
- Date Issued: 2003
Insect Pest Management and Ecological Research, GH Walter book review
- Authors: Villet, Martin H
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442060 , vital:73952 , https://doi.org/10.1111/j.1570-7458.2009.00824.x
- Description: This book is a 275-page argument for the place of theoretical biology in pest management research. Its general message is that contemporary pest management research emphasizes application of technology or strategic research at the expense of application of knowledge or tactical research, and that even the application of knowledge should actually be subservient to the development and extension of knowledge, theoretical research. Whenever we study a pest, we are presented with an opportunity to enhance, rather than merely apply, knowledge. It is argued that pest management research is currently failing itself because it is not doing this, and several areas of theoretical biology are identified as offering ways out of this situation.
- Full Text:
- Date Issued: 2003
- Authors: Villet, Martin H
- Date: 2003
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/442060 , vital:73952 , https://doi.org/10.1111/j.1570-7458.2009.00824.x
- Description: This book is a 275-page argument for the place of theoretical biology in pest management research. Its general message is that contemporary pest management research emphasizes application of technology or strategic research at the expense of application of knowledge or tactical research, and that even the application of knowledge should actually be subservient to the development and extension of knowledge, theoretical research. Whenever we study a pest, we are presented with an opportunity to enhance, rather than merely apply, knowledge. It is argued that pest management research is currently failing itself because it is not doing this, and several areas of theoretical biology are identified as offering ways out of this situation.
- Full Text:
- Date Issued: 2003
Integrating information security into corporate culture
- Authors: Thomson, Kerry-Lynn
- Date: 2003
- Subjects: Computer security -- Management , Corporate governance , Corporate culture
- Language: English
- Type: Thesis , Masters , MTech (Information Technology)
- Identifier: vital:10801 , http://hdl.handle.net/10948/132 , Computer security -- Management , Corporate governance , Corporate culture
- Description: Introduction: There are many components that are required for an organisation to be successful in its chosen field. These components vary from corporate culture, to corporate leadership, to effective protection of important assets. These and many more contribute to the success of an organisation. One component that should be a definitive part in the strategy of any organisation is information security. Information security is one of the fastest growing sub-disciplines in the Information Technology industry, indicating the importance of this field (Zylt, 2001, online). Information security is concerned with the implementation and support of control measures to protect the confidentiality, integrity and availability of electronically stored information (BS 7799-1, 1999, p 1). Information security is achieved by applying control measures that will lessen the threat, reduce the vulnerability or diminish the impact of losing an information asset. However, as a result of the fact that an increasing number of employees have access to information, the protection of information is no longer only dependent on physical and technical controls, but also, to a large extent, on the actions of employees utilising information resources. All employees have a role to play in safeguarding information and they need guidance in fulfilling these roles (Barnard, 1998, p 12). This guidance should originate from senior management, using good corporate governance practices. The effective leadership resulting from good corporate governance practices is another component in an organisation that contributes to its success (King Report, 2001, p 11). Corporate governance is defined as the exercise of power over and responsibility for corporate entities (Blackwell Publishers, 2000, online). Senior management, as part of its corporate governance duties, should encourage employees to adhere to the behaviour specified by senior management to contribute towards a successful organisation. Senior management should not dictate this behaviour, but encourage it as naturally as possible, resulting in the correct behaviour becoming part of the corporate culture. If the inner workings of organisations are explored it would be found that there are many hidden forces at work that determine how senior management and the employees relate to one another and to customers. These hidden forces are collectively called the culture of the organisation (Hagberg Consulting Group, 2002, online). Cultural assumptions in organisations grow around how people in the organisation relate to each other, but that is only a small part of what corporate culture actually covers (Schein, 1999, p 28). Corporate culture is the outcome of all the collective, taken-for-granted assumptions that a group has learned throughout history. Corporate culture is the residue of success. In other words, it is the set of procedures that senior management and employees of an organisation follow in order to be successful (Schein, 1999, p 29). Cultivating an effective corporate culture, managing an organisation using efficient corporate governance practices and protecting the valuable information assets of an organisation through an effective information security program are, individually, all important components in the success of an organisation. One of the biggest questions with regard to these three fields is the relationship that should exist between information security, corporate governance and corporate culture. In other words, what can the senior management of an organisation, using effective corporate governance practices, do to ensure that information security practices become a subconscious response in the corporate culture?.
- Full Text:
- Date Issued: 2003
- Authors: Thomson, Kerry-Lynn
- Date: 2003
- Subjects: Computer security -- Management , Corporate governance , Corporate culture
- Language: English
- Type: Thesis , Masters , MTech (Information Technology)
- Identifier: vital:10801 , http://hdl.handle.net/10948/132 , Computer security -- Management , Corporate governance , Corporate culture
- Description: Introduction: There are many components that are required for an organisation to be successful in its chosen field. These components vary from corporate culture, to corporate leadership, to effective protection of important assets. These and many more contribute to the success of an organisation. One component that should be a definitive part in the strategy of any organisation is information security. Information security is one of the fastest growing sub-disciplines in the Information Technology industry, indicating the importance of this field (Zylt, 2001, online). Information security is concerned with the implementation and support of control measures to protect the confidentiality, integrity and availability of electronically stored information (BS 7799-1, 1999, p 1). Information security is achieved by applying control measures that will lessen the threat, reduce the vulnerability or diminish the impact of losing an information asset. However, as a result of the fact that an increasing number of employees have access to information, the protection of information is no longer only dependent on physical and technical controls, but also, to a large extent, on the actions of employees utilising information resources. All employees have a role to play in safeguarding information and they need guidance in fulfilling these roles (Barnard, 1998, p 12). This guidance should originate from senior management, using good corporate governance practices. The effective leadership resulting from good corporate governance practices is another component in an organisation that contributes to its success (King Report, 2001, p 11). Corporate governance is defined as the exercise of power over and responsibility for corporate entities (Blackwell Publishers, 2000, online). Senior management, as part of its corporate governance duties, should encourage employees to adhere to the behaviour specified by senior management to contribute towards a successful organisation. Senior management should not dictate this behaviour, but encourage it as naturally as possible, resulting in the correct behaviour becoming part of the corporate culture. If the inner workings of organisations are explored it would be found that there are many hidden forces at work that determine how senior management and the employees relate to one another and to customers. These hidden forces are collectively called the culture of the organisation (Hagberg Consulting Group, 2002, online). Cultural assumptions in organisations grow around how people in the organisation relate to each other, but that is only a small part of what corporate culture actually covers (Schein, 1999, p 28). Corporate culture is the outcome of all the collective, taken-for-granted assumptions that a group has learned throughout history. Corporate culture is the residue of success. In other words, it is the set of procedures that senior management and employees of an organisation follow in order to be successful (Schein, 1999, p 29). Cultivating an effective corporate culture, managing an organisation using efficient corporate governance practices and protecting the valuable information assets of an organisation through an effective information security program are, individually, all important components in the success of an organisation. One of the biggest questions with regard to these three fields is the relationship that should exist between information security, corporate governance and corporate culture. In other words, what can the senior management of an organisation, using effective corporate governance practices, do to ensure that information security practices become a subconscious response in the corporate culture?.
- Full Text:
- Date Issued: 2003
Intelligent design and biology
- Authors: Ramsden, Sean
- Date: 2003
- Subjects: Hume, David, 1711-1776 , Darwin, Charles, 1809-1882 , Paley, William, 1743-1805 , Dembski, William A., 1960- , Behe, Michael J., 1952- , Evolution (Biology) , Probabilities , Naturalism , Intelligent design (Teleology)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2739 , http://hdl.handle.net/10962/d1007561 , Hume, David, 1711-1776 , Darwin, Charles, 1809-1882 , Paley, William, 1743-1805 , Dembski, William A., 1960- , Behe, Michael J., 1952- , Evolution (Biology) , Probabilities , Naturalism , Intelligent design (Teleology)
- Description: The thesis is that contrary to the received popular wisdom, the combination of David Hume's sceptical enquiry and Charles Darwin's provision of an alternative theoretical framework to the then current paradigm of natural theology did not succeed in defeating the design argument. I argue that William Paley's work best represented the status quo in the philosophy of biology circa 1800 and that with the logical mechanisms provided us by William Dembski in his seminal work on probability, there is a strong argument for thr work of Michael Behe to stand in a similar position today to that of Paley two centuries ago. The argument runs as follows: In Sections 1 and 2 of Chapter 1 I introduce the issues. In Section 3 I argue that William Paley's exposition of the design argument was archetypical of the natural theology school and that given Hume's already published criticism of the argument, Paley for one did not feel the design argument to be done for. I further argue in Section 4 that Hume in fact did no such thing and that neither did he see himself as having done so, but that the design argument was weak rather than fallacious. In Section 5 I outline the demise of natural theology as the dominant school of thought in the philosophy of biology, ascribing this to the rise of Darwinism and subsequently neo-Darwinism. I argue that design arguments were again not defeated but went into abeyance with the rise of a new paradigm associated with Darwinism, namely methodological naturalism. In Chapter 2 I advance the project by a discussion of William Dembski's formulation of design inferences, demonstrating their value in both everyday and technical usage. This is stated in Section 1. In Sections 2 and 3 I discuss Dembski's treatment of probability, whilst in Section 4 I examine Dembski's tying of different levels of probability to different mechanisms of explanation used in explicating the world. Section 5 is my analysis of the logic of the formal statement of the design argument according to Dembski. In Section 6 I encapsulate objections to Dembski. I conclude the chapter (with Section 7) by claiming that Dembski forwards a coherent model of design inferences that can be used in demonstrating that there is little difference between the way that Paley came to his conclusions two centuries ago and how modem philosophers of biology (such as I take Michael Behe to be, albeit that by profession he is a scientist) come to theirs when offering design explanations. Inference to the best explanation is demonstrated as lying at the crux of design arguments. In Chapter 3 I draw together the work of Michael Behe and Paley, showing through the mechanism of Dembski's work that they are closely related in many respects and that neither position is to be lightly dismissed. Section 1 introduces this. In Section 2 I introduce Behe's concept of irreducible complexity in the light of (functional) explanation. Section 3 is a detailed analysis of irreducible complexity. Section 4 raises and covers objections to Behe with the general theme being that (neo-) Darwinians beg the question against him. In Section 4 I apply the Dembskian mechanic directly to Behe's work. I argue that Behe does not quite meet the Dembskian criteria he needs to in order for his argument to stand as anything other than defeasible. However, in Section 5 I conclude by arguing that this is exactly what we are to expect from Behe's and similar theories, even within competing paradigms, in the philosophy of biology, given that inference to the best explanation is the logical lever therein at work. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2003
- Authors: Ramsden, Sean
- Date: 2003
- Subjects: Hume, David, 1711-1776 , Darwin, Charles, 1809-1882 , Paley, William, 1743-1805 , Dembski, William A., 1960- , Behe, Michael J., 1952- , Evolution (Biology) , Probabilities , Naturalism , Intelligent design (Teleology)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2739 , http://hdl.handle.net/10962/d1007561 , Hume, David, 1711-1776 , Darwin, Charles, 1809-1882 , Paley, William, 1743-1805 , Dembski, William A., 1960- , Behe, Michael J., 1952- , Evolution (Biology) , Probabilities , Naturalism , Intelligent design (Teleology)
- Description: The thesis is that contrary to the received popular wisdom, the combination of David Hume's sceptical enquiry and Charles Darwin's provision of an alternative theoretical framework to the then current paradigm of natural theology did not succeed in defeating the design argument. I argue that William Paley's work best represented the status quo in the philosophy of biology circa 1800 and that with the logical mechanisms provided us by William Dembski in his seminal work on probability, there is a strong argument for thr work of Michael Behe to stand in a similar position today to that of Paley two centuries ago. The argument runs as follows: In Sections 1 and 2 of Chapter 1 I introduce the issues. In Section 3 I argue that William Paley's exposition of the design argument was archetypical of the natural theology school and that given Hume's already published criticism of the argument, Paley for one did not feel the design argument to be done for. I further argue in Section 4 that Hume in fact did no such thing and that neither did he see himself as having done so, but that the design argument was weak rather than fallacious. In Section 5 I outline the demise of natural theology as the dominant school of thought in the philosophy of biology, ascribing this to the rise of Darwinism and subsequently neo-Darwinism. I argue that design arguments were again not defeated but went into abeyance with the rise of a new paradigm associated with Darwinism, namely methodological naturalism. In Chapter 2 I advance the project by a discussion of William Dembski's formulation of design inferences, demonstrating their value in both everyday and technical usage. This is stated in Section 1. In Sections 2 and 3 I discuss Dembski's treatment of probability, whilst in Section 4 I examine Dembski's tying of different levels of probability to different mechanisms of explanation used in explicating the world. Section 5 is my analysis of the logic of the formal statement of the design argument according to Dembski. In Section 6 I encapsulate objections to Dembski. I conclude the chapter (with Section 7) by claiming that Dembski forwards a coherent model of design inferences that can be used in demonstrating that there is little difference between the way that Paley came to his conclusions two centuries ago and how modem philosophers of biology (such as I take Michael Behe to be, albeit that by profession he is a scientist) come to theirs when offering design explanations. Inference to the best explanation is demonstrated as lying at the crux of design arguments. In Chapter 3 I draw together the work of Michael Behe and Paley, showing through the mechanism of Dembski's work that they are closely related in many respects and that neither position is to be lightly dismissed. Section 1 introduces this. In Section 2 I introduce Behe's concept of irreducible complexity in the light of (functional) explanation. Section 3 is a detailed analysis of irreducible complexity. Section 4 raises and covers objections to Behe with the general theme being that (neo-) Darwinians beg the question against him. In Section 4 I apply the Dembskian mechanic directly to Behe's work. I argue that Behe does not quite meet the Dembskian criteria he needs to in order for his argument to stand as anything other than defeasible. However, in Section 5 I conclude by arguing that this is exactly what we are to expect from Behe's and similar theories, even within competing paradigms, in the philosophy of biology, given that inference to the best explanation is the logical lever therein at work. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2003
Intelligent monitoring and control system for a friction stir welding process
- Authors: Kruger, Grant
- Date: 2003
- Subjects: Friction welding
- Language: English
- Type: Thesis , Masters , MTech (Electrical Engineering)
- Identifier: vital:10823 , http://hdl.handle.net/10948/273 , Friction welding
- Description: A Friction Stir Welding machine is proposed and built to allow future research into the process and to provide a framework from which the application of intelligent manufacturing to industrial processes can be investigated. Initially a literature survey was conducted upon which the design of the machine could be based. The conversion of a conventional milling machine into a Friction Stir Welding machine by applying modern monitoring and control systems is then presented. Complete digital control was used to drive actuators and monitor sensors. A wireless chuck mounted monitoring system was implemented, enabling forces, torques, temperature and speed of the tool to be obtained directly from the process. Software based on a hierarchical Open Systems Architectural design, incorporating modularity, interoperability, portability and extensibility is implemented. This experimental setup is used to analyze the Friction Stir Welding process by performing data analysis using statistical methods. Three independent variables (weld speed, spindle speed and plunge depth) were varied and the independent variables (forces, torques, power, temperature, speed, etc) recorded using the implemented software. The statistical analysis includes the analysis of variants, regression analysis and the creation of surface plots. Using these results, certain linguistic rules for process control are proposed. An intelligent controller is designed and discussed, using the derived rules to improve and optimize certain aspects of the process encountered during the experimental phase of the research.
- Full Text:
- Date Issued: 2003
- Authors: Kruger, Grant
- Date: 2003
- Subjects: Friction welding
- Language: English
- Type: Thesis , Masters , MTech (Electrical Engineering)
- Identifier: vital:10823 , http://hdl.handle.net/10948/273 , Friction welding
- Description: A Friction Stir Welding machine is proposed and built to allow future research into the process and to provide a framework from which the application of intelligent manufacturing to industrial processes can be investigated. Initially a literature survey was conducted upon which the design of the machine could be based. The conversion of a conventional milling machine into a Friction Stir Welding machine by applying modern monitoring and control systems is then presented. Complete digital control was used to drive actuators and monitor sensors. A wireless chuck mounted monitoring system was implemented, enabling forces, torques, temperature and speed of the tool to be obtained directly from the process. Software based on a hierarchical Open Systems Architectural design, incorporating modularity, interoperability, portability and extensibility is implemented. This experimental setup is used to analyze the Friction Stir Welding process by performing data analysis using statistical methods. Three independent variables (weld speed, spindle speed and plunge depth) were varied and the independent variables (forces, torques, power, temperature, speed, etc) recorded using the implemented software. The statistical analysis includes the analysis of variants, regression analysis and the creation of surface plots. Using these results, certain linguistic rules for process control are proposed. An intelligent controller is designed and discussed, using the derived rules to improve and optimize certain aspects of the process encountered during the experimental phase of the research.
- Full Text:
- Date Issued: 2003
Intercohort cannibalism and parturition-associated behaviour of captive-bred swordtail, Xiphophorus helleri (Pisces: Poeciliidae)
- Jones, Clifford Louis Wilshire
- Authors: Jones, Clifford Louis Wilshire
- Date: 2003
- Subjects: Poeciliidae -- Behavior Xiphophorus helleri Fish culture
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5351 , http://hdl.handle.net/10962/d1007812
- Description: Adult fish that belong to the family Poeciliidae cannibalise juveniles, both in the wild and under captive conditions, but this behaviour has only been partly investigated in the Poeciliidae in some of the commercially valuable species. The objective of the research is to develop an understanding of intercohort cannibalism and parturition-associated behaviour in captive-bred swordtail (Xiphophorus helleri), with applications to industry and future research of other poeciliids. Experiments investigating the effect of adult stocking density and sex ratio on the production of juveniles were used to determine if cannibalism occurs under culture conditions. The average rate of intercohort cannibalism ranged from (5.5 to 53.9%), and was positively density dependent and independent of sex ratio, indicating that males and females were probably equally cannibalistic. The highest number of juveniles (1725.7±141.4) produced per tank over 70 days was obtained from two males and eight females. To develop a better understanding of adult and juvenile behaviour during parturition, fish were observed under controlled laboratory conditions using video and behaviours such as attack (burst of speed by an adult in the direction of a juvenile), escape (avoidance of cannibalism after attack) and cannibalism (predation of a live juvenile by an adult), for example, were identified. Under laboratory conditions most young escaped in downward direction after attack (49%) and most utilised the refuge made that was made available. Furthermore, most attacks (62-65%) and cannibalism (57-84%) occurred at the bottom. Since the presence of refuge significantly increased the rate of juvenile survival under culture conditions, it was hypothesised that the rate of cannibalism could be reduced under farming conditions if juveniles were protected when they escaped downwards. This hypothesis was accepted as it was found that refuge at the bottom of the water column or the inclusion of a false-bottom reduced the rate of cannibalism by 49% and 72%, respectively. Similarly, the hypothesise that the rate of cannibalism could be reduced if juveniles where given protection when escaping sideways (32% of juveniles escaped sideways in the laboratory) was also accepted when tested under farm-scale conditions because a false-side reduced the rate of cannibalism by an average of 45%. Since males and females were equally responsible for cannibalising juveniles in the laboratory, it was hypothesised that the rate of cannibalism would decrease proportionately with the removal of males (Le. 20% of the cannibals) from the population; the removal of males under farming conditions resulted in a 19.5% reduction in the rate of cannibalism. Since older juveniles were better able to escape cannibalism than neonates and since adults habituate to stimuli that previously resulted in attack behaviour, it was hypothesised that the rate of cannibalism would remain unaffected by the length of time that juveniles were exposed to adults in the breeding tanks. This hypothesis was also accepted when tested under farm conditions. However, some hypotheses based on laboratory observations were not accepted. For example, a constant low light intensity did not appear to decrease the rate of cannibalism under farm conditions; also, the occurrence of dead and deformed juveniles went unnoticed in the laboratory, and under farm conditions, where adults did not have access to the bottom of the tank, 10% of the harvest consisted of dead and deformed juveniles. It is concluded that technologies, such as bottom-refuge or a false-side, that increase the size of the liveharvest and allow for the removal of potentially less viable offspring are recommended for the commercial production of poeciliids. The overall similarity of X. helleri behaviour between the laboratory experiments and the farm-scale trials suggests that the post-partum behaviour of X. helleri remains consistent under these different conditions; thus, behaviour under one set of conditions may be used to predict behaviour under other conditions. The application and significance of extrapolations to industry and future research of X. helleri and possibly other poeciliids were discussed and the most applicable laboratory observations with the highest extrapolation capacity were proposed. Furthermore, techniques were developed to aid industry and future researchers in making predictions relating to behaviour of X. helleri under different conditions based on laboratory observations. The results were used to develop a model indicating that selection pressures against cannibalism are not likely to exist at the rate of cannibalism observed here since the potential genetic gain through kin survival and inclusive fitness was shown to be greater than any potential genetiC loss experienced by a victim of cannibalism. The model was successfully tested under a range of social conditions. Other possible explanations for cannibalism in poeciliids, such as parental manipulation, nutritional advantages, opportunistic predation and the recovery of energy are discussed. It is suggested that the most likely proximate cause of cannibalism under captive conditions is opportunistic predation. The theory that cannibalism ensures that only viable genes of the victim are expressed, through inclusive fitness, is a possible ultimate cause of cannibalism, which may have been inherited from feral ancestors of captive-bred X. helleri.
- Full Text:
- Date Issued: 2003
- Authors: Jones, Clifford Louis Wilshire
- Date: 2003
- Subjects: Poeciliidae -- Behavior Xiphophorus helleri Fish culture
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5351 , http://hdl.handle.net/10962/d1007812
- Description: Adult fish that belong to the family Poeciliidae cannibalise juveniles, both in the wild and under captive conditions, but this behaviour has only been partly investigated in the Poeciliidae in some of the commercially valuable species. The objective of the research is to develop an understanding of intercohort cannibalism and parturition-associated behaviour in captive-bred swordtail (Xiphophorus helleri), with applications to industry and future research of other poeciliids. Experiments investigating the effect of adult stocking density and sex ratio on the production of juveniles were used to determine if cannibalism occurs under culture conditions. The average rate of intercohort cannibalism ranged from (5.5 to 53.9%), and was positively density dependent and independent of sex ratio, indicating that males and females were probably equally cannibalistic. The highest number of juveniles (1725.7±141.4) produced per tank over 70 days was obtained from two males and eight females. To develop a better understanding of adult and juvenile behaviour during parturition, fish were observed under controlled laboratory conditions using video and behaviours such as attack (burst of speed by an adult in the direction of a juvenile), escape (avoidance of cannibalism after attack) and cannibalism (predation of a live juvenile by an adult), for example, were identified. Under laboratory conditions most young escaped in downward direction after attack (49%) and most utilised the refuge made that was made available. Furthermore, most attacks (62-65%) and cannibalism (57-84%) occurred at the bottom. Since the presence of refuge significantly increased the rate of juvenile survival under culture conditions, it was hypothesised that the rate of cannibalism could be reduced under farming conditions if juveniles were protected when they escaped downwards. This hypothesis was accepted as it was found that refuge at the bottom of the water column or the inclusion of a false-bottom reduced the rate of cannibalism by 49% and 72%, respectively. Similarly, the hypothesise that the rate of cannibalism could be reduced if juveniles where given protection when escaping sideways (32% of juveniles escaped sideways in the laboratory) was also accepted when tested under farm-scale conditions because a false-side reduced the rate of cannibalism by an average of 45%. Since males and females were equally responsible for cannibalising juveniles in the laboratory, it was hypothesised that the rate of cannibalism would decrease proportionately with the removal of males (Le. 20% of the cannibals) from the population; the removal of males under farming conditions resulted in a 19.5% reduction in the rate of cannibalism. Since older juveniles were better able to escape cannibalism than neonates and since adults habituate to stimuli that previously resulted in attack behaviour, it was hypothesised that the rate of cannibalism would remain unaffected by the length of time that juveniles were exposed to adults in the breeding tanks. This hypothesis was also accepted when tested under farm conditions. However, some hypotheses based on laboratory observations were not accepted. For example, a constant low light intensity did not appear to decrease the rate of cannibalism under farm conditions; also, the occurrence of dead and deformed juveniles went unnoticed in the laboratory, and under farm conditions, where adults did not have access to the bottom of the tank, 10% of the harvest consisted of dead and deformed juveniles. It is concluded that technologies, such as bottom-refuge or a false-side, that increase the size of the liveharvest and allow for the removal of potentially less viable offspring are recommended for the commercial production of poeciliids. The overall similarity of X. helleri behaviour between the laboratory experiments and the farm-scale trials suggests that the post-partum behaviour of X. helleri remains consistent under these different conditions; thus, behaviour under one set of conditions may be used to predict behaviour under other conditions. The application and significance of extrapolations to industry and future research of X. helleri and possibly other poeciliids were discussed and the most applicable laboratory observations with the highest extrapolation capacity were proposed. Furthermore, techniques were developed to aid industry and future researchers in making predictions relating to behaviour of X. helleri under different conditions based on laboratory observations. The results were used to develop a model indicating that selection pressures against cannibalism are not likely to exist at the rate of cannibalism observed here since the potential genetic gain through kin survival and inclusive fitness was shown to be greater than any potential genetiC loss experienced by a victim of cannibalism. The model was successfully tested under a range of social conditions. Other possible explanations for cannibalism in poeciliids, such as parental manipulation, nutritional advantages, opportunistic predation and the recovery of energy are discussed. It is suggested that the most likely proximate cause of cannibalism under captive conditions is opportunistic predation. The theory that cannibalism ensures that only viable genes of the victim are expressed, through inclusive fitness, is a possible ultimate cause of cannibalism, which may have been inherited from feral ancestors of captive-bred X. helleri.
- Full Text:
- Date Issued: 2003
Interrogate the information society:
- Authors: Berger, Guy
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159181 , vital:40275 , https://hdl.handle.net/10520/EJC146276
- Description: If there is one thing journalists should know about the "Information Society", it's this: never use the phrase as if its meaning speaks for itself. This is one of the most slippery and contentious phrases yet to grace contemporary discourse. For a start, why "Information Society" and not "Knowledge Society"? And why "society" and not "economy"? This is not academic semantics. There are wholly different meanings at stake with different implications for journalists, politicians, policy makers and many more.
- Full Text:
- Date Issued: 2003
- Authors: Berger, Guy
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/159181 , vital:40275 , https://hdl.handle.net/10520/EJC146276
- Description: If there is one thing journalists should know about the "Information Society", it's this: never use the phrase as if its meaning speaks for itself. This is one of the most slippery and contentious phrases yet to grace contemporary discourse. For a start, why "Information Society" and not "Knowledge Society"? And why "society" and not "economy"? This is not academic semantics. There are wholly different meanings at stake with different implications for journalists, politicians, policy makers and many more.
- Full Text:
- Date Issued: 2003
Intervention in Bosnia-Herzegovina: lessons of peace‐maintenance for Africa?
- Authors: Bischoff, Paul, 1954-
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161365 , vital:40620 , DOI: 10.1080/10220460309545430
- Description: The Bosnian model is potentially a useful model for the development of a new strategic framework for African conflicts, particularly in situations where international organisations such as the United Nations are overstretched and regional organisations wish to take charge of peacebuilding operations.
- Full Text:
- Date Issued: 2003
- Authors: Bischoff, Paul, 1954-
- Date: 2003
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/161365 , vital:40620 , DOI: 10.1080/10220460309545430
- Description: The Bosnian model is potentially a useful model for the development of a new strategic framework for African conflicts, particularly in situations where international organisations such as the United Nations are overstretched and regional organisations wish to take charge of peacebuilding operations.
- Full Text:
- Date Issued: 2003
Introduction [to the book "Scatter the Shrilling Bones" by Sithembele Isaac Xhegwana]
- Authors: Wright, Laurence
- Date: 2003
- Language: English
- Type: text , article
- Identifier: vital:7056 , http://hdl.handle.net/10962/d1007417
- Description: preprint , Scatter the Shrilling Bones by Sithembele Xhegwana comprises an ordered sequence of poems that conveys a journey both literal and spiritual. Revisitation is the organizing principle of the collection – the return to rural sources and origins by a consciousness estranged and illumined by modernity (cf. ‘The Return’). Underlying the collection is the theme of the night journey, whose archetype in western culture is Odysseus’ descent to the underworld – a pattern identified as such in the concluding essay ‘Starting from my Place: Notes on an Aesthetic’. The underworld here is literally the return to the home territory – a journey from Cape Town to the rural Eastern Cape – but also a revisiting of the mental world of traditional Africa: ‘Here at home, here all guilt begins’ (‘Homecoming’). The return journey is haunted by nightmare memories of mental illness, the schizophrenic episodes accompanying (or occasioned by?) the poet’s initial encounters with modernity. This illness is represented as both pathological and cultural – a price paid for challenging and rejecting the old certainties while grappling with new assumptions: “He undermines the ancestors, That’s why he suffers. Let him.” (‘To Himself’)
- Full Text:
- Date Issued: 2003
- Authors: Wright, Laurence
- Date: 2003
- Language: English
- Type: text , article
- Identifier: vital:7056 , http://hdl.handle.net/10962/d1007417
- Description: preprint , Scatter the Shrilling Bones by Sithembele Xhegwana comprises an ordered sequence of poems that conveys a journey both literal and spiritual. Revisitation is the organizing principle of the collection – the return to rural sources and origins by a consciousness estranged and illumined by modernity (cf. ‘The Return’). Underlying the collection is the theme of the night journey, whose archetype in western culture is Odysseus’ descent to the underworld – a pattern identified as such in the concluding essay ‘Starting from my Place: Notes on an Aesthetic’. The underworld here is literally the return to the home territory – a journey from Cape Town to the rural Eastern Cape – but also a revisiting of the mental world of traditional Africa: ‘Here at home, here all guilt begins’ (‘Homecoming’). The return journey is haunted by nightmare memories of mental illness, the schizophrenic episodes accompanying (or occasioned by?) the poet’s initial encounters with modernity. This illness is represented as both pathological and cultural – a price paid for challenging and rejecting the old certainties while grappling with new assumptions: “He undermines the ancestors, That’s why he suffers. Let him.” (‘To Himself’)
- Full Text:
- Date Issued: 2003
Investigation of the comparative cost-effectiveness of different strategies for the management of multidrug-resistant tuberculosis
- Authors: Rockcliffe, Nicole
- Date: 2003
- Subjects: Tuberculosis , Multidrug resistance , Tuberculosis -- Treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3788 , http://hdl.handle.net/10962/d1003266 , Tuberculosis , Multidrug resistance , Tuberculosis -- Treatment
- Description: The tuberculosis epidemic is escalating in South Africa as well as globally. This escalation is exacerbated by the increasing prevalence of multidrug-resistant tuberculosis (MDRTB), which is defined by the World Health Organisation (WHO) as resistance of Mycobacteria to at least isoniazid and rifampicin. Multi-drug resistant tuberculosis is estimated to occur in 1-2% of newly diagnosed tuberculosis (TB) patients and in 4-8% of previously treated patients. MDRTB is both difficult and expensive to treat, costing up to 126 times that of drug-sensitive TB. Resource constrained countries such as South Africa often lack both the money and the infrastructure to treat this disease. The aim of this project was to determine whether the performance of a systematic review with subsequent economic modelling could influence the decision making process for policy makers. Data was gathered and an economic evaluation of MDRTB treatment was performed from the perspective of the South African Department of Health. Three treatment alternatives were identified: a protocol regimen of second line anti-tuberculosis agents, as recommended in the South African guidelines for MDRTB, an appropriate regimen designed for each patient according to the results of culture and drug susceptibility tests, and non-drug management. A decision-analysis model using DATA 3.0 by Treeage® was developed to estimate the costs of each alternative. Outcomes were measured in terms of cost alone as well as the ‘number of cases cured’ and the number of ‘years of life saved’ for patients dying, being cured or failing treatment. Drug, hospital and laboratory costs incurred using each alternative were included in the analysis. A sensitivity analysis was performed on all variables in order to identify threshold values that would change the outcome of the evaluation. Results of the decision analysis indicate that the individualised regimen was both the cheaper and more cost-effective regimen of the two active treatment options, and was estimated to cost R50 661 per case cured and R2 070 per year of life saved. The protocol regimen was estimated to cost R73 609 per case cured and R2 741 per year of life saved. The outcome of the decision analysis was sensitive to changes in some of the variables used to model the disease, particularly the daily cost of drugs, the length of time spent in hospital and the length of treatment received by those patients dying or failing treatment. This modelling exercise highlighted significant deficiencies in the quality of evidence on MDRTB management available to policy makers. Pragmatic choices based on operational and other logistic concerns may need to be reviewed when further information becomes available. A case can be made for the establishment of a national database of costing and efficacy information to guide future policy revisions of the South African MDRTB treatment programme, which is resource intensive and of only moderate efficacy. However, due to the widely disparate range of studies on which this evaluation was based, the outcome of the study may not be credible. In this case, the use of a systematic review with subsequent economic modelling could not validly influence policy-makers to change the decision that they made on the basis of drug availability.
- Full Text:
- Date Issued: 2003
- Authors: Rockcliffe, Nicole
- Date: 2003
- Subjects: Tuberculosis , Multidrug resistance , Tuberculosis -- Treatment
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3788 , http://hdl.handle.net/10962/d1003266 , Tuberculosis , Multidrug resistance , Tuberculosis -- Treatment
- Description: The tuberculosis epidemic is escalating in South Africa as well as globally. This escalation is exacerbated by the increasing prevalence of multidrug-resistant tuberculosis (MDRTB), which is defined by the World Health Organisation (WHO) as resistance of Mycobacteria to at least isoniazid and rifampicin. Multi-drug resistant tuberculosis is estimated to occur in 1-2% of newly diagnosed tuberculosis (TB) patients and in 4-8% of previously treated patients. MDRTB is both difficult and expensive to treat, costing up to 126 times that of drug-sensitive TB. Resource constrained countries such as South Africa often lack both the money and the infrastructure to treat this disease. The aim of this project was to determine whether the performance of a systematic review with subsequent economic modelling could influence the decision making process for policy makers. Data was gathered and an economic evaluation of MDRTB treatment was performed from the perspective of the South African Department of Health. Three treatment alternatives were identified: a protocol regimen of second line anti-tuberculosis agents, as recommended in the South African guidelines for MDRTB, an appropriate regimen designed for each patient according to the results of culture and drug susceptibility tests, and non-drug management. A decision-analysis model using DATA 3.0 by Treeage® was developed to estimate the costs of each alternative. Outcomes were measured in terms of cost alone as well as the ‘number of cases cured’ and the number of ‘years of life saved’ for patients dying, being cured or failing treatment. Drug, hospital and laboratory costs incurred using each alternative were included in the analysis. A sensitivity analysis was performed on all variables in order to identify threshold values that would change the outcome of the evaluation. Results of the decision analysis indicate that the individualised regimen was both the cheaper and more cost-effective regimen of the two active treatment options, and was estimated to cost R50 661 per case cured and R2 070 per year of life saved. The protocol regimen was estimated to cost R73 609 per case cured and R2 741 per year of life saved. The outcome of the decision analysis was sensitive to changes in some of the variables used to model the disease, particularly the daily cost of drugs, the length of time spent in hospital and the length of treatment received by those patients dying or failing treatment. This modelling exercise highlighted significant deficiencies in the quality of evidence on MDRTB management available to policy makers. Pragmatic choices based on operational and other logistic concerns may need to be reviewed when further information becomes available. A case can be made for the establishment of a national database of costing and efficacy information to guide future policy revisions of the South African MDRTB treatment programme, which is resource intensive and of only moderate efficacy. However, due to the widely disparate range of studies on which this evaluation was based, the outcome of the study may not be credible. In this case, the use of a systematic review with subsequent economic modelling could not validly influence policy-makers to change the decision that they made on the basis of drug availability.
- Full Text:
- Date Issued: 2003
Investigations into the asymmetric reduction of ketones
- Authors: Bena, Luvuyo Clifford
- Date: 2003
- Subjects: Ketones , Asymmetric synthesis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11065 , http://hdl.handle.net/10948/323 , Ketones , Asymmetric synthesis
- Description: A six-step synthesis of salbutamol from methyl salicylate with an overall yield of 17% has been completed, although the yield was not optimised. In the process, Zn(BH4)2 was found to selectively reduce a ketone carbonyl group in the presence of an ester unit. In contrast, borane was found to reduce both the ketone and ester carbonyl groups. Reduction of phenacyl bromide with borane in the presence of chiral catalysts based on (R)-alaninol and (R,S)-ephidrine resulted a measure of enantioselectivity in the product. However, the configuration of the alcohol obtained in the case of (R)-alaninol was contrary to expectations based both on experimental trends observed elsewhere as well as our own theoretical predictions. The asymmetric reduction of methyl 5-bromoacetyl-2-benzyloxybenzoate was accomplished with both borane and Zn(BH4)2 in the presence of a range of chiral catalysts. Optically active products were obtained in all cases, although the optical rotations were significantly smaller in the case of Zn(BH4)2. Unfortunately, we were not successful in determining the enantiomeric excesses of these reactions. The use of a NMR lanthanide shift reagent resulted in a complex spectrum that was impossible to interpret unambiguously. This presumably arises from the presence of several Lewis base sites in the product at which complexation with the shift reagent can take place. It was also not possible to determine the optical rotation of salbutamol itself owing to the relatively small amount of material obtained. A conformational analysis of salbutamol, where NMR data was correlated with molecular modelling results, was successfully carried out and revealed a strong preference for that conformer family characterised by O–C–C–N and Ar–C–C–N torsion angles of ca. 60º and 180º, respectively. Interestingly, these conformers are found to be stabilised by OH…N rather than NH…O hydrogen bonding. This study has also confirmed the effectiveness of the MMFF94 force field for conformational analysis studies in compounds of this kind. Lastly, a relatively simple method for modelling the BH3/oxazaborolidine reduction of ketones at the PM3 semiempirical MO level of approximation was devised. This approach has provided insights into the mechanism of the reaction and has furthermore enabled us to predict the enantioselectivities likely to result from various catalysts and ketones. In comparing our theoretical and experimental findings, an anomalous result was observed in the case of (R)-alaninol; this will have to be investigated further, particularly at the experimental level. However, we believe that our approach provides a sound basis for aiding the design and screening of new, potentially better catalysts.
- Full Text:
- Date Issued: 2003
- Authors: Bena, Luvuyo Clifford
- Date: 2003
- Subjects: Ketones , Asymmetric synthesis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11065 , http://hdl.handle.net/10948/323 , Ketones , Asymmetric synthesis
- Description: A six-step synthesis of salbutamol from methyl salicylate with an overall yield of 17% has been completed, although the yield was not optimised. In the process, Zn(BH4)2 was found to selectively reduce a ketone carbonyl group in the presence of an ester unit. In contrast, borane was found to reduce both the ketone and ester carbonyl groups. Reduction of phenacyl bromide with borane in the presence of chiral catalysts based on (R)-alaninol and (R,S)-ephidrine resulted a measure of enantioselectivity in the product. However, the configuration of the alcohol obtained in the case of (R)-alaninol was contrary to expectations based both on experimental trends observed elsewhere as well as our own theoretical predictions. The asymmetric reduction of methyl 5-bromoacetyl-2-benzyloxybenzoate was accomplished with both borane and Zn(BH4)2 in the presence of a range of chiral catalysts. Optically active products were obtained in all cases, although the optical rotations were significantly smaller in the case of Zn(BH4)2. Unfortunately, we were not successful in determining the enantiomeric excesses of these reactions. The use of a NMR lanthanide shift reagent resulted in a complex spectrum that was impossible to interpret unambiguously. This presumably arises from the presence of several Lewis base sites in the product at which complexation with the shift reagent can take place. It was also not possible to determine the optical rotation of salbutamol itself owing to the relatively small amount of material obtained. A conformational analysis of salbutamol, where NMR data was correlated with molecular modelling results, was successfully carried out and revealed a strong preference for that conformer family characterised by O–C–C–N and Ar–C–C–N torsion angles of ca. 60º and 180º, respectively. Interestingly, these conformers are found to be stabilised by OH…N rather than NH…O hydrogen bonding. This study has also confirmed the effectiveness of the MMFF94 force field for conformational analysis studies in compounds of this kind. Lastly, a relatively simple method for modelling the BH3/oxazaborolidine reduction of ketones at the PM3 semiempirical MO level of approximation was devised. This approach has provided insights into the mechanism of the reaction and has furthermore enabled us to predict the enantioselectivities likely to result from various catalysts and ketones. In comparing our theoretical and experimental findings, an anomalous result was observed in the case of (R)-alaninol; this will have to be investigated further, particularly at the experimental level. However, we believe that our approach provides a sound basis for aiding the design and screening of new, potentially better catalysts.
- Full Text:
- Date Issued: 2003
IsiXhosa insect names from the Eastern Cape, South Africa
- Mkize, Nolwazi, Villet, Martin H, Robertson, Mark P
- Authors: Mkize, Nolwazi , Villet, Martin H , Robertson, Mark P
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6859 , http://hdl.handle.net/10962/d1011148
- Description: We present a list of isiXhosa names for a wide diversity of South African insects, and their English translations and scientific names, to contribute to bridging the knowledge gap between rural development workers and isiXhosa speakers. We interviewed 51 people in their homes at eight sites across the Eastern Cape and also included words from a published dictionary. We found 151 insect names, and categorized them into personal, dialectal and standard categories. Response-frequency distributions of the categories of names showed that the dialectal and standard lists were essentially complete. Sample accumulation curves showed levelling-off within sites and across the whole study, demonstrating that samples were adequate. The literal translations of some names show that isiXhosa speakers relate insects either to people, to their habitat and/or to their behaviour. The list can contribute to the standardization of knowledge of insects' indigenous names in South Africa for a variety of practical applications such as agricultural training and health services.
- Full Text:
- Date Issued: 2003
- Authors: Mkize, Nolwazi , Villet, Martin H , Robertson, Mark P
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6859 , http://hdl.handle.net/10962/d1011148
- Description: We present a list of isiXhosa names for a wide diversity of South African insects, and their English translations and scientific names, to contribute to bridging the knowledge gap between rural development workers and isiXhosa speakers. We interviewed 51 people in their homes at eight sites across the Eastern Cape and also included words from a published dictionary. We found 151 insect names, and categorized them into personal, dialectal and standard categories. Response-frequency distributions of the categories of names showed that the dialectal and standard lists were essentially complete. Sample accumulation curves showed levelling-off within sites and across the whole study, demonstrating that samples were adequate. The literal translations of some names show that isiXhosa speakers relate insects either to people, to their habitat and/or to their behaviour. The list can contribute to the standardization of knowledge of insects' indigenous names in South Africa for a variety of practical applications such as agricultural training and health services.
- Full Text:
- Date Issued: 2003
Isolation of antigenic peptides of Cowdria ruminantium and their encoding genes using a genome-derived phage display library
- Authors: Fehrsen, Jeanni
- Date: 2003
- Subjects: Bacteriophages -- Genetics Ruminants -- Diseases Heartwater
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3920 , http://hdl.handle.net/10962/d1003979
- Description: The development of new and effective vaccines and immunodiagnostic reagents requires the characterisation of antigenically relevant proteins and their interactions with the products of the immune system. Phage display technology was investigated as a means of elucidating some of the antigenic properties of the rickettsial parasite, Cowdria ruminantium (Cowdria). Randomly fragmented gene-derived libraries have been useful in elucidating viral and other epitopes, but only limited work has been done with entire genomes. A phage display library expressing a repertoire of Cowdria peptides was constructed. It was sufficiently large to represent the organism's genome, but lacked phages displaying peptides coded for by genes containing a Pvu II restriction enzyme site, including the one coding for the major antigenic protein 1 (MAP1). This was considered advantageous since MAP1 is immunodominant and has already been well characterised. Affinity selection with antibodies against Cowdria proteins other than MAP1 allowed several antibody-reactive peptides to be isolated. These selected sequences were placed in the context of the genome by screening a lambda bacteriophage library and by comparison with Cowdria DNA sequences. Apart from showing that antigenic mimics were present in the phage display library, six open reading frames encoding putative Cowdria proteins were identified. All had similarities to, or motifs in common with, membrane proteins and are thus likely to be exposed to the host's humoral immune system. Some of the proteins identified were larger than the antigens used to elicit the antibodies used for selection, probably as a result of the presence of cross-reactive epitopes. Despite limitations experienced when extending a fragmented-gene approach for epitope location to genomes, it was possible to identify an antigenic region on MAP1 by comparison with selected mimics. In addition, binding peptide sequences were identified with two monoclonal antibodies that had been raised against non-Cowdria antigens. An epitope on the VP7 protein of bluetongue virus was identified and peptides were found that reacted with a monoclonal antibody directed against malignant catarrhal fever virus. Thus, apart from being able to identify several potentially important Cowdria epitopes and genes, the fragmented-genome library holds promise as a universal reagent for identifying useful mimics.
- Full Text:
- Date Issued: 2003
- Authors: Fehrsen, Jeanni
- Date: 2003
- Subjects: Bacteriophages -- Genetics Ruminants -- Diseases Heartwater
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3920 , http://hdl.handle.net/10962/d1003979
- Description: The development of new and effective vaccines and immunodiagnostic reagents requires the characterisation of antigenically relevant proteins and their interactions with the products of the immune system. Phage display technology was investigated as a means of elucidating some of the antigenic properties of the rickettsial parasite, Cowdria ruminantium (Cowdria). Randomly fragmented gene-derived libraries have been useful in elucidating viral and other epitopes, but only limited work has been done with entire genomes. A phage display library expressing a repertoire of Cowdria peptides was constructed. It was sufficiently large to represent the organism's genome, but lacked phages displaying peptides coded for by genes containing a Pvu II restriction enzyme site, including the one coding for the major antigenic protein 1 (MAP1). This was considered advantageous since MAP1 is immunodominant and has already been well characterised. Affinity selection with antibodies against Cowdria proteins other than MAP1 allowed several antibody-reactive peptides to be isolated. These selected sequences were placed in the context of the genome by screening a lambda bacteriophage library and by comparison with Cowdria DNA sequences. Apart from showing that antigenic mimics were present in the phage display library, six open reading frames encoding putative Cowdria proteins were identified. All had similarities to, or motifs in common with, membrane proteins and are thus likely to be exposed to the host's humoral immune system. Some of the proteins identified were larger than the antigens used to elicit the antibodies used for selection, probably as a result of the presence of cross-reactive epitopes. Despite limitations experienced when extending a fragmented-gene approach for epitope location to genomes, it was possible to identify an antigenic region on MAP1 by comparison with selected mimics. In addition, binding peptide sequences were identified with two monoclonal antibodies that had been raised against non-Cowdria antigens. An epitope on the VP7 protein of bluetongue virus was identified and peptides were found that reacted with a monoclonal antibody directed against malignant catarrhal fever virus. Thus, apart from being able to identify several potentially important Cowdria epitopes and genes, the fragmented-genome library holds promise as a universal reagent for identifying useful mimics.
- Full Text:
- Date Issued: 2003