Exploring Grade 12 biology teachers' perceptions and experiences of the dissemination and utilization of Examiners' reports in the Khomas region of Namibia: a case study
- Authors: Bezuidenhoudt, Anthea
- Date: 2015
- Subjects: Biology -- Examinations -- Namibia , Biology -- Study and teaching -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2021 , http://hdl.handle.net/10962/d1017332
- Description: Teachers’ perceptions are that currently dissemination in schools is ineffective and must change. The tensions that surround the dissemination of the reports are late arrival of Examiners’ reports which clash with preparation of learners for the first term examinations. Furthermore, the time the Examiners’ reports get into teachers’ hands are late and thus result in teachers rushing through it to incorporate the recommendations given in it in the second term or in some instances teachers do not attend to it at all. The number of copies of the Examiners’ reports provided to schools appears to be inadequate. HODs still having to duplicate reports before disseminating them add to their work load and further delay dissemination of the reports to individual subject teachers. Although the teaching and learning approach in Namibian classrooms should be based on LCE, dissemination of the actual physical reports are currently restricted to teachers only with them only verbally communicating feedback given in the reports to their learners. Support in dissemination of Examiners’ reports from peers and superiors in the majority of the schools appear to be lacking. Changes would like to be seen in the timing the Examiners’ reports are available at schools, the number of hard copies provided to schools and exploring and embarking on alternative ways of disseminating the reports. The percentage of utilization of the Examiners’ reports is relatively high, yet still not the optimum. A reasonable number of Namibian learners are disadvantaged and not exposed to a source of information that can make their Biology learning more efficient because some of their teachers are not using Examiners’ reports in their teaching. The main reason for non-utilization of the reports by Biology teachers is a result of inefficient dissemination at individual schools. The argument being that if the reports are not given to the teachers they and especially novice teachers will not know about the existence of this useful teaching and learning resource. Examiners’ reports are an important and systematic impartial source of high quality data on learning in the Namibian education system. Therefore, effective dissemination and utilization of the reports must be advocated and strengthened. DNEA and the Khomas regional office should embark on tapping into available development in information technology by doing research into the possibility of disseminating the Examiners’ reports electronically. A pilot in this regard should be conducted in the Khomas region as a measure to ensure dissemination can become more efficient in the future. To ensure that teachers optimally utilize the Examiners’ reports, they should be provided to schools when the school first term commences. The Khomas regional office should strengthen their involvement in utilization by arranging annual workshops where the content of the reports can be discussed to ensure that the feedback given in the reports can aid in developing and strengthening Biology teachers’ subject content knowledge as well as pedagogical content knowledge. Optimal utilization of Examiners’ reports can enable mediation in learners which can ensure effective learning and mastery of Biology by learners which can ultimately lead to an improvement in pass rate in Biology. Therefore, appropriate support to aid teachers’ professional development can enhance maximum utilization. Furthermore, an area for future research could be to give the Examiners’ reports to learners to determine the impact it has on their learning.
- Full Text:
- Date Issued: 2015
- Authors: Bezuidenhoudt, Anthea
- Date: 2015
- Subjects: Biology -- Examinations -- Namibia , Biology -- Study and teaching -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2021 , http://hdl.handle.net/10962/d1017332
- Description: Teachers’ perceptions are that currently dissemination in schools is ineffective and must change. The tensions that surround the dissemination of the reports are late arrival of Examiners’ reports which clash with preparation of learners for the first term examinations. Furthermore, the time the Examiners’ reports get into teachers’ hands are late and thus result in teachers rushing through it to incorporate the recommendations given in it in the second term or in some instances teachers do not attend to it at all. The number of copies of the Examiners’ reports provided to schools appears to be inadequate. HODs still having to duplicate reports before disseminating them add to their work load and further delay dissemination of the reports to individual subject teachers. Although the teaching and learning approach in Namibian classrooms should be based on LCE, dissemination of the actual physical reports are currently restricted to teachers only with them only verbally communicating feedback given in the reports to their learners. Support in dissemination of Examiners’ reports from peers and superiors in the majority of the schools appear to be lacking. Changes would like to be seen in the timing the Examiners’ reports are available at schools, the number of hard copies provided to schools and exploring and embarking on alternative ways of disseminating the reports. The percentage of utilization of the Examiners’ reports is relatively high, yet still not the optimum. A reasonable number of Namibian learners are disadvantaged and not exposed to a source of information that can make their Biology learning more efficient because some of their teachers are not using Examiners’ reports in their teaching. The main reason for non-utilization of the reports by Biology teachers is a result of inefficient dissemination at individual schools. The argument being that if the reports are not given to the teachers they and especially novice teachers will not know about the existence of this useful teaching and learning resource. Examiners’ reports are an important and systematic impartial source of high quality data on learning in the Namibian education system. Therefore, effective dissemination and utilization of the reports must be advocated and strengthened. DNEA and the Khomas regional office should embark on tapping into available development in information technology by doing research into the possibility of disseminating the Examiners’ reports electronically. A pilot in this regard should be conducted in the Khomas region as a measure to ensure dissemination can become more efficient in the future. To ensure that teachers optimally utilize the Examiners’ reports, they should be provided to schools when the school first term commences. The Khomas regional office should strengthen their involvement in utilization by arranging annual workshops where the content of the reports can be discussed to ensure that the feedback given in the reports can aid in developing and strengthening Biology teachers’ subject content knowledge as well as pedagogical content knowledge. Optimal utilization of Examiners’ reports can enable mediation in learners which can ensure effective learning and mastery of Biology by learners which can ultimately lead to an improvement in pass rate in Biology. Therefore, appropriate support to aid teachers’ professional development can enhance maximum utilization. Furthermore, an area for future research could be to give the Examiners’ reports to learners to determine the impact it has on their learning.
- Full Text:
- Date Issued: 2015
Challenges of post-apartheid state-owned company pension fund reform: a case study of the controversy around the Transnet-Transport Pension Fund
- Authors: Goqoza, Noluyolo Juliet
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSocSc
- Identifier: http://hdl.handle.net/10962/54766 , vital:26610
- Description: This thesis examines the restructuring of the pension funds of Transnet, a South African state-owned company involved in transportation, from the 1990s. Two of its main pension funds, the Transport-Transnet Pension sub-Fund (TTPF) and the Transnet Second Defined Benefit Fund (TSDBF), have been surrounded by controversy, with major court actions brought by aggrieved pensioners in 2006-2012 and again from 2013, and smaller cases in 1997-1999 and 2004. (There were also a number of smaller cases, mostly unsuccessful, but the thesis will not examine them). The case that started in 2013 is the biggest class action in the country‟s history, and makes claims of serious mismanagement and bad faith against the Transnet management. But the fundamental grievance is that (according to the 2013 legal case) “more than 80% of pensioners earn less than R4 000.00 a month… 62 % earn less than R2 500.00… 45% of the pensioners earn less than the state‟s ordinary old-age pension” grant for the poor. Although that case is ongoing, this thesis examines the background and controversies that frame the case. It provides an overview of the history and development of the South African pensions system and South African state-owned companies; it examines how these have been shaped by the apartheid and post-apartheid periods, and by the rise of neo-liberalism; it examines the evolution of Transnet and its pensions systems, from the early days of the South African Railways and Harbours Administration (SAR&H, formed 1910), to its restructuring into the South African Transport Services (SATS) in 1982, and then into Transnet in 1990. The thesis shows that the operations of the TTPF and TSDBF, which are closed to new members, have had serious effects on pensioners that rely upon them. Pensions are very low (the main reason for the various court cases), and this is for a range of reasons. Annual increases in pensions are formally set at below-inflation levels, leading to falling real incomes. More pressure on pensioners‟ livelihoods has arisen from Transnet‟s cuts to other benefits, like the medical aid Transmed, provided to pensioners. While the schemes are solvent, the pensions generally started at a low base, partly because most pensioners were relatively poorly paid workers before retirement (and the pensions were linked to former salaries). There is also a racial dimension: while most white workers at SAR&H/ SATS and Transnet were poorly paid, black, Coloured and Indian workers were paid even worse, and, further, were only brought into the pension schemes late. Both TTPF and TSDBF are defined benefit funds, which means members are guaranteed specific benefits at retirement, with the employer obligated to inject funds to meet shortfalls where needed. Yet neither the state nor Transnet has been willing to take actions to lift the basic pensions, such as investments into the funds, or to make systematic ex gratia payments to bring the pensions to a reasonable level, to remove historic racial inequalities between pensioners, to increase medical aid co-payments or coverage or to otherwise address the pensioners‟ situation. It does not seem that the reason for the problems is that the two funds have been severely mismanaged or asset-stripped, as alleged in the 2013 class action: it must be noted that both funds report surpluses. But the surpluses are possible because the pensions are low and falling in real terms, and the numbers of pensioners declining due to deaths. It seems clear that Transnet is unable or unwilling to act to decisively improve the situation of the pensioners: ensuring a surplus on existing pension funds is a major goal. This is partly because Transnet itself has ongoing financial problems, and partly because it operates in the context of neo-liberal restructuring, like corporatisation, commercialisation and privatisation, which places limits on the additional funding of the funds. At the same time, the pensioners have very little real, as opposed to a nominal, say in the administration of the pension schemes, limiting their ability to affect the rules and administration or raise issues. The thesis seeks to use historical institutionalism, which sees policies and major institutions, including state-owned companies, as shaped by power and conflict, especially between classes. This is used to try and explain changing state policies and the changing role and actions of state-owned companies, as a way of understanding Transnet‟s actions, as well as its treatment of its pensioners.
- Full Text:
- Date Issued: 2015
- Authors: Goqoza, Noluyolo Juliet
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MSocSc
- Identifier: http://hdl.handle.net/10962/54766 , vital:26610
- Description: This thesis examines the restructuring of the pension funds of Transnet, a South African state-owned company involved in transportation, from the 1990s. Two of its main pension funds, the Transport-Transnet Pension sub-Fund (TTPF) and the Transnet Second Defined Benefit Fund (TSDBF), have been surrounded by controversy, with major court actions brought by aggrieved pensioners in 2006-2012 and again from 2013, and smaller cases in 1997-1999 and 2004. (There were also a number of smaller cases, mostly unsuccessful, but the thesis will not examine them). The case that started in 2013 is the biggest class action in the country‟s history, and makes claims of serious mismanagement and bad faith against the Transnet management. But the fundamental grievance is that (according to the 2013 legal case) “more than 80% of pensioners earn less than R4 000.00 a month… 62 % earn less than R2 500.00… 45% of the pensioners earn less than the state‟s ordinary old-age pension” grant for the poor. Although that case is ongoing, this thesis examines the background and controversies that frame the case. It provides an overview of the history and development of the South African pensions system and South African state-owned companies; it examines how these have been shaped by the apartheid and post-apartheid periods, and by the rise of neo-liberalism; it examines the evolution of Transnet and its pensions systems, from the early days of the South African Railways and Harbours Administration (SAR&H, formed 1910), to its restructuring into the South African Transport Services (SATS) in 1982, and then into Transnet in 1990. The thesis shows that the operations of the TTPF and TSDBF, which are closed to new members, have had serious effects on pensioners that rely upon them. Pensions are very low (the main reason for the various court cases), and this is for a range of reasons. Annual increases in pensions are formally set at below-inflation levels, leading to falling real incomes. More pressure on pensioners‟ livelihoods has arisen from Transnet‟s cuts to other benefits, like the medical aid Transmed, provided to pensioners. While the schemes are solvent, the pensions generally started at a low base, partly because most pensioners were relatively poorly paid workers before retirement (and the pensions were linked to former salaries). There is also a racial dimension: while most white workers at SAR&H/ SATS and Transnet were poorly paid, black, Coloured and Indian workers were paid even worse, and, further, were only brought into the pension schemes late. Both TTPF and TSDBF are defined benefit funds, which means members are guaranteed specific benefits at retirement, with the employer obligated to inject funds to meet shortfalls where needed. Yet neither the state nor Transnet has been willing to take actions to lift the basic pensions, such as investments into the funds, or to make systematic ex gratia payments to bring the pensions to a reasonable level, to remove historic racial inequalities between pensioners, to increase medical aid co-payments or coverage or to otherwise address the pensioners‟ situation. It does not seem that the reason for the problems is that the two funds have been severely mismanaged or asset-stripped, as alleged in the 2013 class action: it must be noted that both funds report surpluses. But the surpluses are possible because the pensions are low and falling in real terms, and the numbers of pensioners declining due to deaths. It seems clear that Transnet is unable or unwilling to act to decisively improve the situation of the pensioners: ensuring a surplus on existing pension funds is a major goal. This is partly because Transnet itself has ongoing financial problems, and partly because it operates in the context of neo-liberal restructuring, like corporatisation, commercialisation and privatisation, which places limits on the additional funding of the funds. At the same time, the pensioners have very little real, as opposed to a nominal, say in the administration of the pension schemes, limiting their ability to affect the rules and administration or raise issues. The thesis seeks to use historical institutionalism, which sees policies and major institutions, including state-owned companies, as shaped by power and conflict, especially between classes. This is used to try and explain changing state policies and the changing role and actions of state-owned companies, as a way of understanding Transnet‟s actions, as well as its treatment of its pensioners.
- Full Text:
- Date Issued: 2015
In a town called Harmony
- Authors: Tsibolane, Pitso
- Date: 2015
- Subjects: South African fiction (English) -- 21st century , Creative writing (Higher education) , South African fiction (English) -- Study and teaching (Higher)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5995 , http://hdl.handle.net/10962/d1017779
- Description: A novella of crime and suspense set in the townships surrounding the mining town of Welkom Two friends, both ex-miners, start a welding business only to see it fail because of interference by corrupt officials To make ends meet, they are drawn into the world of illegal gold-mining, working with criminals who employ ‘zama-zamas’: desperate foreign nationals who are prepared to live and work in the abandoned mine tunnels underground The friends make money, but the dark practices of illegal mining put a strain on their relationship, their values, and their family ties.
- Full Text:
- Date Issued: 2015
- Authors: Tsibolane, Pitso
- Date: 2015
- Subjects: South African fiction (English) -- 21st century , Creative writing (Higher education) , South African fiction (English) -- Study and teaching (Higher)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5995 , http://hdl.handle.net/10962/d1017779
- Description: A novella of crime and suspense set in the townships surrounding the mining town of Welkom Two friends, both ex-miners, start a welding business only to see it fail because of interference by corrupt officials To make ends meet, they are drawn into the world of illegal gold-mining, working with criminals who employ ‘zama-zamas’: desperate foreign nationals who are prepared to live and work in the abandoned mine tunnels underground The friends make money, but the dark practices of illegal mining put a strain on their relationship, their values, and their family ties.
- Full Text:
- Date Issued: 2015
Towards an evaluation and protection strategy for critical infrastructure
- Authors: Gottschalk, Jason Howard
- Date: 2015
- Subjects: Computer crimes -- Prevention , Computer networks -- Security measures , Computer crimes -- Law and legislation -- South Africa , Public works -- Security measures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4721 , http://hdl.handle.net/10962/d1018793
- Description: Critical Infrastructure is often overlooked from an Information Security perspective as being of high importance to protect which may result in Critical Infrastructure being at risk to Cyber related attacks with potential dire consequences. Furthermore, what is considered Critical Infrastructure is often a complex discussion, with varying opinions across audiences. Traditional Critical Infrastructure included power stations, water, sewage pump stations, gas pipe lines, power grids and a new entrant, the “internet of things”. This list is not complete and a constant challenge exists in identifying Critical Infrastructure and its interdependencies. The purpose of this research is to highlight the importance of protecting Critical Infrastructure as well as proposing a high level framework aiding in the identification and securing of Critical Infrastructure. To achieve this, key case studies involving Cyber crime and Cyber warfare, as well as the identification of attack vectors and impact on against Critical Infrastructure (as applicable to Critical Infrastructure where possible), were identified and discussed. Furthermore industry related material was researched as to identify key controls that would aid in protecting Critical Infrastructure. The identification of initiatives that countries were pursuing, that would aid in the protection of Critical Infrastructure, were identified and discussed. Research was conducted into the various standards, frameworks and methodologies available to aid in the identification, remediation and ultimately the protection of Critical Infrastructure. A key output of the research was the development of a hybrid approach to identifying Critical Infrastructure, associated vulnerabilities and an approach for remediation with specific metrics (based on the research performed). The conclusion based on the research is that there is often a need and a requirement to identify and protect Critical Infrastructure however this is usually initiated or driven by non-owners of Critical Infrastructure (Governments, governing bodies, standards bodies and security consultants). Furthermore where there are active initiative by owners very often the suggested approaches are very high level in nature with little direct guidance available for very immature environments.
- Full Text:
- Date Issued: 2015
- Authors: Gottschalk, Jason Howard
- Date: 2015
- Subjects: Computer crimes -- Prevention , Computer networks -- Security measures , Computer crimes -- Law and legislation -- South Africa , Public works -- Security measures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4721 , http://hdl.handle.net/10962/d1018793
- Description: Critical Infrastructure is often overlooked from an Information Security perspective as being of high importance to protect which may result in Critical Infrastructure being at risk to Cyber related attacks with potential dire consequences. Furthermore, what is considered Critical Infrastructure is often a complex discussion, with varying opinions across audiences. Traditional Critical Infrastructure included power stations, water, sewage pump stations, gas pipe lines, power grids and a new entrant, the “internet of things”. This list is not complete and a constant challenge exists in identifying Critical Infrastructure and its interdependencies. The purpose of this research is to highlight the importance of protecting Critical Infrastructure as well as proposing a high level framework aiding in the identification and securing of Critical Infrastructure. To achieve this, key case studies involving Cyber crime and Cyber warfare, as well as the identification of attack vectors and impact on against Critical Infrastructure (as applicable to Critical Infrastructure where possible), were identified and discussed. Furthermore industry related material was researched as to identify key controls that would aid in protecting Critical Infrastructure. The identification of initiatives that countries were pursuing, that would aid in the protection of Critical Infrastructure, were identified and discussed. Research was conducted into the various standards, frameworks and methodologies available to aid in the identification, remediation and ultimately the protection of Critical Infrastructure. A key output of the research was the development of a hybrid approach to identifying Critical Infrastructure, associated vulnerabilities and an approach for remediation with specific metrics (based on the research performed). The conclusion based on the research is that there is often a need and a requirement to identify and protect Critical Infrastructure however this is usually initiated or driven by non-owners of Critical Infrastructure (Governments, governing bodies, standards bodies and security consultants). Furthermore where there are active initiative by owners very often the suggested approaches are very high level in nature with little direct guidance available for very immature environments.
- Full Text:
- Date Issued: 2015
Appraising the appraisal framework: evidence from Grahamstown property advertisements
- Authors: Beangstrom, Tracy
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/54744 , vital:26608
- Description: This thesis considers how interpersonal meaning choices in property advertisements are best reflected in a context of constraint in Grahamstown, South Africa, using and appraising Martin & White’s (2005) APPRAISAL Framework. The study is comparative in two senses since the data is analysed using Martin & White’s (2005) APPRAISAL Framework and a revision to it, and property advertisements from two competing estate agencies are analysed: Remax Frontier Properties and Pam Golding Properties. An initial strict application of Martin & White’s (2005) framework is followed by a second, based on analyst difficulties and framework limitations experienced in the first analysis, as well as those experienced by other researchers. Revisions to the original framework include added ‘local’, context-driven features and sub-categories: Exclusivity and Convenience in Attitude, a Scale of Intensity in Graduation, and a category ‘Invite’ in Engagement. These enable a richer, more detailed account of the alignment strategies and interpersonal micro-politics at play in the property advertisements than is possible using the original framework. Findings from the analyses reveal four facts of note. Firstly, that while the original Martin & White (2005) APPRAISAL Framework captures a general level of interpersonal meaning in the data, it does so more fully when it includes contextual and contextually-driven categories that are informed by local knowledge. Secondly, two levels of meaning are expressed in the data. One is aimed at an ‘external’ audience; the other, truer, fuller and more contentious, is aimed at what appears to be the intended audience only. Thirdly, and relatedly, specific contextual and cultural knowledge is needed by the intended audience to access the intended meaning. Fourthly, both estate agencies promote values of high prestige, exclusivity, elitism and wealth as their intended meaning to align a like-minded audience, although Remax Frontier Properties attribute these values to location and features of the home to a greater extent than Pam Golding Properties, who place greater emphasis on the size of the home. The thesis suggests further avenues for research into the discourse of property advertising, as well as into overcoming certain context-specific limitations of the APPRAISAL Framework.
- Full Text:
- Date Issued: 2015
- Authors: Beangstrom, Tracy
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/54744 , vital:26608
- Description: This thesis considers how interpersonal meaning choices in property advertisements are best reflected in a context of constraint in Grahamstown, South Africa, using and appraising Martin & White’s (2005) APPRAISAL Framework. The study is comparative in two senses since the data is analysed using Martin & White’s (2005) APPRAISAL Framework and a revision to it, and property advertisements from two competing estate agencies are analysed: Remax Frontier Properties and Pam Golding Properties. An initial strict application of Martin & White’s (2005) framework is followed by a second, based on analyst difficulties and framework limitations experienced in the first analysis, as well as those experienced by other researchers. Revisions to the original framework include added ‘local’, context-driven features and sub-categories: Exclusivity and Convenience in Attitude, a Scale of Intensity in Graduation, and a category ‘Invite’ in Engagement. These enable a richer, more detailed account of the alignment strategies and interpersonal micro-politics at play in the property advertisements than is possible using the original framework. Findings from the analyses reveal four facts of note. Firstly, that while the original Martin & White (2005) APPRAISAL Framework captures a general level of interpersonal meaning in the data, it does so more fully when it includes contextual and contextually-driven categories that are informed by local knowledge. Secondly, two levels of meaning are expressed in the data. One is aimed at an ‘external’ audience; the other, truer, fuller and more contentious, is aimed at what appears to be the intended audience only. Thirdly, and relatedly, specific contextual and cultural knowledge is needed by the intended audience to access the intended meaning. Fourthly, both estate agencies promote values of high prestige, exclusivity, elitism and wealth as their intended meaning to align a like-minded audience, although Remax Frontier Properties attribute these values to location and features of the home to a greater extent than Pam Golding Properties, who place greater emphasis on the size of the home. The thesis suggests further avenues for research into the discourse of property advertising, as well as into overcoming certain context-specific limitations of the APPRAISAL Framework.
- Full Text:
- Date Issued: 2015
Engaging within zones of proximal development on Facebook : the case of using Facebook to support learning and mentoring on a NQF Level 5 environmental education, training and development practices learnership
- Authors: Chetty, Preven
- Date: 2015
- Subjects: Social media -- Study and teaching (Higher) -- South Africa , Internet in education , Online social networks , Organizational learning , Employees -- Training of , Group work in education
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2024 , http://hdl.handle.net/10962/d1017335
- Description: This study focuses on two roll-outs of a, year-long National Qualification Framework (NQF) level 5, environmental education learnership in South Africa and attempts at enhancing collaborative learning at workplaces using a familiar social networking site called Facebook. This study uses the Facebook group sites created for the workplace course component of the course as one of the means of data collection. Additional interviews and focus groups with learners and administrators on both Environmental Education Training and Development Practices (EETDP) courses also informed the study. The study is located within the context of the rise of the information age, its effects on socio-ecological landscape at large and ways of using social networking sites in order to facilitate scaffolding and meaning making within zones of proximal development for environmental education learnerships. It also looks at the model of apprenticeship and workplace based learning as it is broadly located at the nexus of the SAQA-led academic inquiry into workplace based learning and professional development. It was found that the use of Facebook on the EETDP learnership allowed for collaborative learning to take place between peer to peer interactions as well as between tutors and learners. It was also noted that scaffolding processes requires both technical assistance and strong instructional input from course tutors. One of the most important findings in terms of collaborative learning and engaging within the Zone of Proximal Development (ZPD) was that learners were able to communicate more effectively and freely with both fellow learners and tutors on course after participating on the Facebook group sites. The study offers recommendations on how a social networking platform like Facebook can be utilised effectively for environmental education. The study recommends that scaffolding of workplace based tasks and concepts needs to be better integrated with the course and in both online and offline interactions between learners. It also illustrates how social networking sites can become powerful tools for creating meaning making when combined with course work.
- Full Text:
- Date Issued: 2015
- Authors: Chetty, Preven
- Date: 2015
- Subjects: Social media -- Study and teaching (Higher) -- South Africa , Internet in education , Online social networks , Organizational learning , Employees -- Training of , Group work in education
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2024 , http://hdl.handle.net/10962/d1017335
- Description: This study focuses on two roll-outs of a, year-long National Qualification Framework (NQF) level 5, environmental education learnership in South Africa and attempts at enhancing collaborative learning at workplaces using a familiar social networking site called Facebook. This study uses the Facebook group sites created for the workplace course component of the course as one of the means of data collection. Additional interviews and focus groups with learners and administrators on both Environmental Education Training and Development Practices (EETDP) courses also informed the study. The study is located within the context of the rise of the information age, its effects on socio-ecological landscape at large and ways of using social networking sites in order to facilitate scaffolding and meaning making within zones of proximal development for environmental education learnerships. It also looks at the model of apprenticeship and workplace based learning as it is broadly located at the nexus of the SAQA-led academic inquiry into workplace based learning and professional development. It was found that the use of Facebook on the EETDP learnership allowed for collaborative learning to take place between peer to peer interactions as well as between tutors and learners. It was also noted that scaffolding processes requires both technical assistance and strong instructional input from course tutors. One of the most important findings in terms of collaborative learning and engaging within the Zone of Proximal Development (ZPD) was that learners were able to communicate more effectively and freely with both fellow learners and tutors on course after participating on the Facebook group sites. The study offers recommendations on how a social networking platform like Facebook can be utilised effectively for environmental education. The study recommends that scaffolding of workplace based tasks and concepts needs to be better integrated with the course and in both online and offline interactions between learners. It also illustrates how social networking sites can become powerful tools for creating meaning making when combined with course work.
- Full Text:
- Date Issued: 2015
Assignment of spin and parity to states in the nucleus ¹⁹⁶T1
- Authors: Uwitonze, Pierre Celestin
- Date: 2015
- Subjects: Nuclear spin , Particles (Nuclear physics) -- Chirality
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5558 , http://hdl.handle.net/10962/d1017903
- Description: This work presents a study of high-spin states in the nucleus ¹⁹⁶Tl via γ-spectroscopy. ¹⁹⁶Tl was produced via the ¹⁹⁷Au(⁴He,5n) ¹⁹⁶Tl reaction at a beam energy of 63 MeV. The γ-γ coincidence measurements were performed using the AFRODITE γ-spectrometer array at iThemba LABS. The previous level scheme of ¹⁹⁶Tl has been extended up to an excitation of 4071 keV including 24 new γ-ray transitions. The spin and parity assignment to levels was made from the directional correlation of oriented nuclei (DCO) and linear polarization anisotropy ratios. An analysis of the B(M1)/B(E2) ratios was found to be consistent with the configuration of πh₉/₂♁vi₁₃/₂ for the ground state band. Although no chiral band was found in ¹⁹⁶TI and ¹⁹⁸TI.
- Full Text:
- Date Issued: 2015
- Authors: Uwitonze, Pierre Celestin
- Date: 2015
- Subjects: Nuclear spin , Particles (Nuclear physics) -- Chirality
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5558 , http://hdl.handle.net/10962/d1017903
- Description: This work presents a study of high-spin states in the nucleus ¹⁹⁶Tl via γ-spectroscopy. ¹⁹⁶Tl was produced via the ¹⁹⁷Au(⁴He,5n) ¹⁹⁶Tl reaction at a beam energy of 63 MeV. The γ-γ coincidence measurements were performed using the AFRODITE γ-spectrometer array at iThemba LABS. The previous level scheme of ¹⁹⁶Tl has been extended up to an excitation of 4071 keV including 24 new γ-ray transitions. The spin and parity assignment to levels was made from the directional correlation of oriented nuclei (DCO) and linear polarization anisotropy ratios. An analysis of the B(M1)/B(E2) ratios was found to be consistent with the configuration of πh₉/₂♁vi₁₃/₂ for the ground state band. Although no chiral band was found in ¹⁹⁶TI and ¹⁹⁸TI.
- Full Text:
- Date Issued: 2015
An evaluation of the potential for implementing adaptive co-management in the Waodani social-ecological system in the Ecuadorian Amazon
- Authors: Bryja, Malgorzata Anna
- Date: 2015
- Subjects: Adaptive natural resource management -- Ecuador -- Reserva de Biosfera Yasuni , Huao Indians -- Ecuador -- Reserva de Biosfera Yasuni , Natural resources -- Co-management -- Ecuador -- Reserva de Biosfera Yasuni , Social ecology -- Ecuador -- Reserva de Biosfera Yasuni , Sustainable development -- Ecuador -- Reserva de Biosfera Yasuni , Resource-based communities -- Ecuador -- Reserva de Biosfera Yasuni , Reserva de Biosfera Yasuni (Ecuador) -- Economic conditions , Huao Indians -- Ecuador -- Reserva de Biosfera Yasuni -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4784 , http://hdl.handle.net/10962/d1018192
- Description: Adaptive co-management (ACM), one of the most prominent management approaches to emerge in the recent years, combines iterative learning, flexibility, and adaptation promoted by adaptive management with the principles of nurturing diversity and fostering collaboration among different partners that underpin co-management philosophy. ACM has been proposed as an approach to address the deficiencies of centralized management in ensuring sustainability of social-ecological systems (SESs) in face of future uncertainties. This thesis aims to evaluate the readiness of resource users (the Waodani) as well as external actors (the Ecuadorian State and NGOs) for future implementation of ACM and thus enhancing the long-term social-ecological sustainability of the Waodani SES located in the Yasuni Biosphere Reserve in the Ecuadorian Amazon. Qualitative data obtained by means of focus groups with the Waodani and individual interviews with external actors and Waodani leaders revealed different levels of readiness for ACM. Firstly, in the case of the Waodani, the insufficient fulfillment of some conditions required for successful ACM as well as intercommunity differences in regards to these conditions can complicate the implementation of ACM, unless sufficient external assistance is offered to the SES. The analysis of NGOs demonstrated, on the other hand, a relative readiness for ACM, providing that such aspects as sufficient funding, long-term commitment to collaboration, and inter-institutional linkages are strengthened. The study also found that the Ecuadorian government’s potential to contribute to ACM is hindered by the lack of readiness to work with the indigenous society as well as by funding and communication challenges. Furthermore, the resource based economy supported by the State limits the scope of innovation and adaptation. Still, as in the case of other actors, overcoming the challenges and transitioning towards adaptive governance and thus ACM could be possible in the long-term, if recent legal and political changes are truly implemented.
- Full Text:
- Date Issued: 2015
- Authors: Bryja, Malgorzata Anna
- Date: 2015
- Subjects: Adaptive natural resource management -- Ecuador -- Reserva de Biosfera Yasuni , Huao Indians -- Ecuador -- Reserva de Biosfera Yasuni , Natural resources -- Co-management -- Ecuador -- Reserva de Biosfera Yasuni , Social ecology -- Ecuador -- Reserva de Biosfera Yasuni , Sustainable development -- Ecuador -- Reserva de Biosfera Yasuni , Resource-based communities -- Ecuador -- Reserva de Biosfera Yasuni , Reserva de Biosfera Yasuni (Ecuador) -- Economic conditions , Huao Indians -- Ecuador -- Reserva de Biosfera Yasuni -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4784 , http://hdl.handle.net/10962/d1018192
- Description: Adaptive co-management (ACM), one of the most prominent management approaches to emerge in the recent years, combines iterative learning, flexibility, and adaptation promoted by adaptive management with the principles of nurturing diversity and fostering collaboration among different partners that underpin co-management philosophy. ACM has been proposed as an approach to address the deficiencies of centralized management in ensuring sustainability of social-ecological systems (SESs) in face of future uncertainties. This thesis aims to evaluate the readiness of resource users (the Waodani) as well as external actors (the Ecuadorian State and NGOs) for future implementation of ACM and thus enhancing the long-term social-ecological sustainability of the Waodani SES located in the Yasuni Biosphere Reserve in the Ecuadorian Amazon. Qualitative data obtained by means of focus groups with the Waodani and individual interviews with external actors and Waodani leaders revealed different levels of readiness for ACM. Firstly, in the case of the Waodani, the insufficient fulfillment of some conditions required for successful ACM as well as intercommunity differences in regards to these conditions can complicate the implementation of ACM, unless sufficient external assistance is offered to the SES. The analysis of NGOs demonstrated, on the other hand, a relative readiness for ACM, providing that such aspects as sufficient funding, long-term commitment to collaboration, and inter-institutional linkages are strengthened. The study also found that the Ecuadorian government’s potential to contribute to ACM is hindered by the lack of readiness to work with the indigenous society as well as by funding and communication challenges. Furthermore, the resource based economy supported by the State limits the scope of innovation and adaptation. Still, as in the case of other actors, overcoming the challenges and transitioning towards adaptive governance and thus ACM could be possible in the long-term, if recent legal and political changes are truly implemented.
- Full Text:
- Date Issued: 2015
The role of seasonality, environmental correlates and edge effects on the diversity and abundance of small mammals in Afromontane forest patches, Eastern Cape, South Africa
- Authors: Junkuhn, Kyle Peter
- Date: 2015
- Subjects: Upland ecology -- South Africa -- Eastern Cape , Mammal populations -- South Africa -- Eastern Cape , Forest animals -- Adaptation -- South Africa -- Eastern Cape , Forest animals -- Climatic factors -- South Africa -- Eastern Cape , Forest animals -- Effect of habitat modification on -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4270 , http://hdl.handle.net/10962/d1018188
- Description: The Eastern Cape contains the majority of the remaining forested areas in South Africa (95.8 percent Coastal forests and 47.6 percent Afromontane forests), however these occur in fragments. Due to the rapid rise in the human population and its needs, conversion of forests to agricultural land and the extraction of timber increases, natural vegetation are lost and this therefore leads to forests becoming fragmented into small forest patches. One of the main consequences of forest fragmentation is loss of contiguous habitat, which is the dominant threat to species globally as it negatively affects both species richness and genetic diversity. This research investigates the effects that forest fragmentation has on small mammal diversity and abundance. The study sampled small mammals in Southern Mistbelt Afromontane forest patches in the Eastern Cape. The first aim of this study was to identify which environmental variable, or combinations of variables, affect the diversity and abundance of small mammals in fragmented forest patches in the Eastern Cape during the austral summer. The second aim was to compare seasonal changes in small mammal diversity and abundance at a forest edge compared to the forest core at Beggars Bush, an Afromontane forest in the Eastern Cape, South Africa. To identify the environmental impacts that different forests have on small mammals, nine different forests were chosen in the Eastern Cape and sampled during the summer in 2013. These nine forests were: Fort Fordyce Forest, Thaba Ndoda Forest, Hogsback Forest, Dassie Kraans Forest, Langeni Forest, Burchell’s Reserve Forest, Maiden Dam Forest and Kagaberg Forest. At each site, three transects of 30 Sherman Traps each were used. Trapping periods within each forest patch lasted between three to five consecutive nights and traps were inspected once a day in the morning. Nine environmental variables were initially identified and after being tested for normality and colinearity, five variables were chosen. These variables were Altitude, Mean Annual Temperature, Gradient, Patch Size and Mean annual potential evaporation. The number of individuals captures and species richness were then incorporated as dependent variables for best subset multiple regression model selection using the Akaike Information Criterion (AIC). For the second aim, the same trapping methods were used when comparing seasonal changes to diversity and abundance within the forest core. However at the forest edge, due to the small size of the forest, only 20 Sherman traps were used in each transect with five traps (25 percent) placed in the grassland and 15 (75 percent) placed in the forest along each transect. This study was one of few to survey small mammal diversity and abundance in fragmented forests in the Eastern Cape. Gradient, patch size and mean annual potential evaporation were the variables that best predicted the individual number of small mammal captures while only gradient best explained species richness. It does however, need to be noted that capture rates and species richness were very low and this would therefore effect the analysis of environmental variables. Future studies should have a larger sample size of forest patches and include more microhabitat environmental variables to determine their effects on small mammal diversity and abundance. However, it should be noted that through climatic extinction filtering, forest mammals are resilient generalists that can tolerate fragmentation effects. Furthermore, it was found that forest edges appear to play a significant role in small mammal diversity and abundance in the Beggars Bush Afromontane forest. Some species were habitat specialists such as Rhabdomys pumilio preferring the grassland habitat and Graphiurus murinus and Aethomys namaquensis the forest habitat, while Myosorex varius was the only species that was not habitat dependant. It was found that there was a greater diversity and abundance at the forest edge compared to within the forest core throughout most of the seasons. One possible flaw was that the sampling methods were different at the edge and within the forest and therefore future studies should ensure that the method stays uniform throughout the study.
- Full Text:
- Date Issued: 2015
- Authors: Junkuhn, Kyle Peter
- Date: 2015
- Subjects: Upland ecology -- South Africa -- Eastern Cape , Mammal populations -- South Africa -- Eastern Cape , Forest animals -- Adaptation -- South Africa -- Eastern Cape , Forest animals -- Climatic factors -- South Africa -- Eastern Cape , Forest animals -- Effect of habitat modification on -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4270 , http://hdl.handle.net/10962/d1018188
- Description: The Eastern Cape contains the majority of the remaining forested areas in South Africa (95.8 percent Coastal forests and 47.6 percent Afromontane forests), however these occur in fragments. Due to the rapid rise in the human population and its needs, conversion of forests to agricultural land and the extraction of timber increases, natural vegetation are lost and this therefore leads to forests becoming fragmented into small forest patches. One of the main consequences of forest fragmentation is loss of contiguous habitat, which is the dominant threat to species globally as it negatively affects both species richness and genetic diversity. This research investigates the effects that forest fragmentation has on small mammal diversity and abundance. The study sampled small mammals in Southern Mistbelt Afromontane forest patches in the Eastern Cape. The first aim of this study was to identify which environmental variable, or combinations of variables, affect the diversity and abundance of small mammals in fragmented forest patches in the Eastern Cape during the austral summer. The second aim was to compare seasonal changes in small mammal diversity and abundance at a forest edge compared to the forest core at Beggars Bush, an Afromontane forest in the Eastern Cape, South Africa. To identify the environmental impacts that different forests have on small mammals, nine different forests were chosen in the Eastern Cape and sampled during the summer in 2013. These nine forests were: Fort Fordyce Forest, Thaba Ndoda Forest, Hogsback Forest, Dassie Kraans Forest, Langeni Forest, Burchell’s Reserve Forest, Maiden Dam Forest and Kagaberg Forest. At each site, three transects of 30 Sherman Traps each were used. Trapping periods within each forest patch lasted between three to five consecutive nights and traps were inspected once a day in the morning. Nine environmental variables were initially identified and after being tested for normality and colinearity, five variables were chosen. These variables were Altitude, Mean Annual Temperature, Gradient, Patch Size and Mean annual potential evaporation. The number of individuals captures and species richness were then incorporated as dependent variables for best subset multiple regression model selection using the Akaike Information Criterion (AIC). For the second aim, the same trapping methods were used when comparing seasonal changes to diversity and abundance within the forest core. However at the forest edge, due to the small size of the forest, only 20 Sherman traps were used in each transect with five traps (25 percent) placed in the grassland and 15 (75 percent) placed in the forest along each transect. This study was one of few to survey small mammal diversity and abundance in fragmented forests in the Eastern Cape. Gradient, patch size and mean annual potential evaporation were the variables that best predicted the individual number of small mammal captures while only gradient best explained species richness. It does however, need to be noted that capture rates and species richness were very low and this would therefore effect the analysis of environmental variables. Future studies should have a larger sample size of forest patches and include more microhabitat environmental variables to determine their effects on small mammal diversity and abundance. However, it should be noted that through climatic extinction filtering, forest mammals are resilient generalists that can tolerate fragmentation effects. Furthermore, it was found that forest edges appear to play a significant role in small mammal diversity and abundance in the Beggars Bush Afromontane forest. Some species were habitat specialists such as Rhabdomys pumilio preferring the grassland habitat and Graphiurus murinus and Aethomys namaquensis the forest habitat, while Myosorex varius was the only species that was not habitat dependant. It was found that there was a greater diversity and abundance at the forest edge compared to within the forest core throughout most of the seasons. One possible flaw was that the sampling methods were different at the edge and within the forest and therefore future studies should ensure that the method stays uniform throughout the study.
- Full Text:
- Date Issued: 2015
Case study : profitability drivers in the South African airline industry : a comparative analysis of SAA and Comair
- Authors: Batidzirai, Davison Herbert
- Date: 2015
- Subjects: South African Airways , Comair Limited , Airlines -- South Africa , Corporate profits -- South Africa , Organizational effectiveness -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:846 , http://hdl.handle.net/10962/d1017191
- Full Text:
- Date Issued: 2015
- Authors: Batidzirai, Davison Herbert
- Date: 2015
- Subjects: South African Airways , Comair Limited , Airlines -- South Africa , Corporate profits -- South Africa , Organizational effectiveness -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:846 , http://hdl.handle.net/10962/d1017191
- Full Text:
- Date Issued: 2015
Formulation, development and assessment of tenofovir disoproxil fumarate-loaded pellets
- Authors: Dube, Tawanda
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/54690 , vital:26600
- Description: Tenofovir disoproxil fumarate (TDF) is a novel nucleotide analog reverse transcriptase inhibitor that is recommended by the WHO for use in first line treatment of HIV infections. Due to the high dose of TDF for anti-retroviral treatment the formulation of a pellet dosage form may improve patient adherence by incorporation of a large dose in a relatively small dosage form. TDF is currently only available in tablet form. A simple, sensitive, selective, rapid, accurate, precise, stability indicating reversed-phase HPLC method was developed and validated in accordance with ICH guidelines and was successfully used for the analysis of TDF raw material and pharmaceutical dosage forms. Preformulation studies included an investigation of TDF-excipient and excipient-excipient interactions with all materials that could potentially be used to produce extruded and spheronized pellets. Nuclear Magnetic Resonance spectroscopy (NMR), Infrared Spectroscopy (IR), Differential Scanning Colorimetry (DSC) and Thermogravimetric analysis were used for identification and purity testing of TDF and all excipients. DSC data revealed that no potential interactions between TDF and the excipients occurred suggesting that incompatibility reactions were unlikely during manufacture and storage. These findings were confirmed by IR analysis that revealed that no physical interaction was likely between any of the excipients used and TDF. DSC data also reveal the existence of the α and β-polymorphs of TDF as evidenced by two enthalpy changes observed on the resultant thermograms. The existence of two polymorphs is unlikely to result in incompatibility and was confirmed by IR analysis. The IR spectra reveal that all characteristic peaks for TDF were present in 1:1 binary mixtures. Therefore TDF is compatible with all excipients tested and thermal analysis confirmed the stability of TDF under manufacturing conditions. The temperature of degradation temperature established through DSC analysis confirmed that degradation during manufacture is unlikely as the temperature of manufacture is lower than that at which degradation occurs. Extrusion and spheronization were the processes used to manufacture TDF pellets as it is a simple and economic approach for production. The effects of extruder and spheronizer speed, amount of spheronization aid and diluents on the pellet size, shape, flow properties and TDF release characteristics were examined. In order to decrease the complexity of analysis and reduce the cost of development a Taguchi orthogonal array design of experiments was successfully applied to evaluate the impact of formulation variables on product characteristics and predict an optimized formulation with a minimum number of experiments. The use of Response Surface Methodology for the development and optimization of pharmaceutical systems, including the optimization of formulation composition, manufacturing processes and/or analytical methods is well established. However the application of RSM requires that accurate, precise and reproducible experimental conditions are used for the generation of reliable data and RSM use is limited due to sensitivity to experimental variability. The benefits of using RSM for formulation optimization include the fact that more than one variable can be investigated at a time and large amounts of information can be generated at the same time ensuring a more efficient process with respect to time and cost. An added advantage of this approach is that mathematical relationships can be generated for the models that are produced and provide formulation scientists with an indication of whether the effect(s) between factors are synergistic or antagonistic. There are several statistical design approaches that use RSM and a Taguchi orthogonal array design was selected for use in this optimization process as fewer experiments are required to generate data for the same number of factors to be investigated when compared to other statistical designs such as Central Composite (CCD) and Box-Behnken designs. The use of RSM clearly demonstrates the impact of different input variables on the % TDF released at 45 min and % TDF loaded into the particles. The amount of sorbitol and Kollidon® CL-M were the only significant variables that affected the % TDF released at 45 min and both excipients had an overall synergistic effect on the in vitro release of TDF. The prediction and manufacture of an optimized formulation led to the production of pellets that met predetermined specifications which was successfully achieved using RSM. The development of a TDF containing pellet dosage form has been achieved and the formulation, manufacture and characterization of the dosage form reveal that the product has the potential to be further developed.
- Full Text:
- Date Issued: 2015
- Authors: Dube, Tawanda
- Date: 2015
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/54690 , vital:26600
- Description: Tenofovir disoproxil fumarate (TDF) is a novel nucleotide analog reverse transcriptase inhibitor that is recommended by the WHO for use in first line treatment of HIV infections. Due to the high dose of TDF for anti-retroviral treatment the formulation of a pellet dosage form may improve patient adherence by incorporation of a large dose in a relatively small dosage form. TDF is currently only available in tablet form. A simple, sensitive, selective, rapid, accurate, precise, stability indicating reversed-phase HPLC method was developed and validated in accordance with ICH guidelines and was successfully used for the analysis of TDF raw material and pharmaceutical dosage forms. Preformulation studies included an investigation of TDF-excipient and excipient-excipient interactions with all materials that could potentially be used to produce extruded and spheronized pellets. Nuclear Magnetic Resonance spectroscopy (NMR), Infrared Spectroscopy (IR), Differential Scanning Colorimetry (DSC) and Thermogravimetric analysis were used for identification and purity testing of TDF and all excipients. DSC data revealed that no potential interactions between TDF and the excipients occurred suggesting that incompatibility reactions were unlikely during manufacture and storage. These findings were confirmed by IR analysis that revealed that no physical interaction was likely between any of the excipients used and TDF. DSC data also reveal the existence of the α and β-polymorphs of TDF as evidenced by two enthalpy changes observed on the resultant thermograms. The existence of two polymorphs is unlikely to result in incompatibility and was confirmed by IR analysis. The IR spectra reveal that all characteristic peaks for TDF were present in 1:1 binary mixtures. Therefore TDF is compatible with all excipients tested and thermal analysis confirmed the stability of TDF under manufacturing conditions. The temperature of degradation temperature established through DSC analysis confirmed that degradation during manufacture is unlikely as the temperature of manufacture is lower than that at which degradation occurs. Extrusion and spheronization were the processes used to manufacture TDF pellets as it is a simple and economic approach for production. The effects of extruder and spheronizer speed, amount of spheronization aid and diluents on the pellet size, shape, flow properties and TDF release characteristics were examined. In order to decrease the complexity of analysis and reduce the cost of development a Taguchi orthogonal array design of experiments was successfully applied to evaluate the impact of formulation variables on product characteristics and predict an optimized formulation with a minimum number of experiments. The use of Response Surface Methodology for the development and optimization of pharmaceutical systems, including the optimization of formulation composition, manufacturing processes and/or analytical methods is well established. However the application of RSM requires that accurate, precise and reproducible experimental conditions are used for the generation of reliable data and RSM use is limited due to sensitivity to experimental variability. The benefits of using RSM for formulation optimization include the fact that more than one variable can be investigated at a time and large amounts of information can be generated at the same time ensuring a more efficient process with respect to time and cost. An added advantage of this approach is that mathematical relationships can be generated for the models that are produced and provide formulation scientists with an indication of whether the effect(s) between factors are synergistic or antagonistic. There are several statistical design approaches that use RSM and a Taguchi orthogonal array design was selected for use in this optimization process as fewer experiments are required to generate data for the same number of factors to be investigated when compared to other statistical designs such as Central Composite (CCD) and Box-Behnken designs. The use of RSM clearly demonstrates the impact of different input variables on the % TDF released at 45 min and % TDF loaded into the particles. The amount of sorbitol and Kollidon® CL-M were the only significant variables that affected the % TDF released at 45 min and both excipients had an overall synergistic effect on the in vitro release of TDF. The prediction and manufacture of an optimized formulation led to the production of pellets that met predetermined specifications which was successfully achieved using RSM. The development of a TDF containing pellet dosage form has been achieved and the formulation, manufacture and characterization of the dosage form reveal that the product has the potential to be further developed.
- Full Text:
- Date Issued: 2015
Conscientious objection and South African medical practitioners' constructions of termination of pregnancy and emergency contraception
- Authors: Chiwandire, Desire
- Date: 2015
- Subjects: Abortion -- South Africa , Abortion -- Moral and ethical aspects -- South Africa , Emergency contraceptives -- South Africa , Contraception -- Moral and ethical aspects -- South Africa , Medical personnel -- Attitudes -- South Africa , Patients -- Legal status, laws, etc. -- South Africa , Reproductive rights -- South Africa , Women's rights -- South Africa , Liberty of conscience
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2888 , http://hdl.handle.net/10962/d1017863
- Description: Aim: The 1996 Choice on Termination of Pregnancy Act decriminalized abortion in South Africa and the South African Medicines Control Council in 2000 approved the dispensing of emergency contraceptive methods by pharmacists to women without a doctor's prescription. This legislation has been hailed as among the most progressive in the world with respect to women's reproductive justice. However the realisation of these rights in practice has not always met expectations in part due to medical practitioners' ethical objections to termination of pregnancy and the provision of related services. The aim of this study was to interpret the varying ways in which medical practitioners frame termination of pregnancy and emergency contraceptive services, their own professional identities and that of their patients/clients. Methods: Sample of 58 doctors and 59 pharmacists drawn from all nine provinces of South Africa. Data collected using an anonymous confidential internet-based self-administered questionnaire. Participants were randomly recruited from online listings of South African doctors and pharmacists practicing in both private and public sectors. Data were analysed using theoretically derived qualitative content analysis. Results: Participants drew on eight frames to justify their willingness or unwillingness to provide termination-of-pregnancy related services: the foetal life frame, the women's rights frame, the balancing frame, the social justice frame, the do no harm frame, the legal and professional obligation frame, the consequences frame and the moral absolutist frame. Conclusion: Health professionals' willingness or unwillingness to provide termination of pregnancy related services is highly dependent on how they frame or understand termination of pregnancy, and how they understand their own professional identities and those of their patients/clients.
- Full Text:
- Date Issued: 2015
- Authors: Chiwandire, Desire
- Date: 2015
- Subjects: Abortion -- South Africa , Abortion -- Moral and ethical aspects -- South Africa , Emergency contraceptives -- South Africa , Contraception -- Moral and ethical aspects -- South Africa , Medical personnel -- Attitudes -- South Africa , Patients -- Legal status, laws, etc. -- South Africa , Reproductive rights -- South Africa , Women's rights -- South Africa , Liberty of conscience
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2888 , http://hdl.handle.net/10962/d1017863
- Description: Aim: The 1996 Choice on Termination of Pregnancy Act decriminalized abortion in South Africa and the South African Medicines Control Council in 2000 approved the dispensing of emergency contraceptive methods by pharmacists to women without a doctor's prescription. This legislation has been hailed as among the most progressive in the world with respect to women's reproductive justice. However the realisation of these rights in practice has not always met expectations in part due to medical practitioners' ethical objections to termination of pregnancy and the provision of related services. The aim of this study was to interpret the varying ways in which medical practitioners frame termination of pregnancy and emergency contraceptive services, their own professional identities and that of their patients/clients. Methods: Sample of 58 doctors and 59 pharmacists drawn from all nine provinces of South Africa. Data collected using an anonymous confidential internet-based self-administered questionnaire. Participants were randomly recruited from online listings of South African doctors and pharmacists practicing in both private and public sectors. Data were analysed using theoretically derived qualitative content analysis. Results: Participants drew on eight frames to justify their willingness or unwillingness to provide termination-of-pregnancy related services: the foetal life frame, the women's rights frame, the balancing frame, the social justice frame, the do no harm frame, the legal and professional obligation frame, the consequences frame and the moral absolutist frame. Conclusion: Health professionals' willingness or unwillingness to provide termination of pregnancy related services is highly dependent on how they frame or understand termination of pregnancy, and how they understand their own professional identities and those of their patients/clients.
- Full Text:
- Date Issued: 2015
The Ecca type section (Permian, South Africa) : an outcrop analogue study of conventional and unconventional hydrocarbon reservoirs
- Authors: Campbell, Stuart Alexander
- Date: 2015
- Subjects: Hydrocarbon reservoirs -- Ecca Group , Geology, Stratigraphic -- Permian , Paleogeography -- Ecca Group , Shale gas -- Ecca Group , Shale gas reservoirs -- Ecca Group , Ecca Group , Ripon Formation (South Africa) , Collingham Formation (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5083 , http://hdl.handle.net/10962/d1018199
- Description: The Karoo Basin of South Africa holds an estimated 906 billion to 11 trillion cubic meters of unconventional shale gas within the shales of the Whitehill and Collingham formations of the Ecca Group. Evaluation of this potential resource has been limited due to the lack of exploration and a scarcity of existing drill core data. In order to circumnavigate this problem this study was undertaken to evaluate the potential target horizons exposed in outcrops along the southern portion of the Karoo Basin, north of Grahamstown in the Eastern Cape Province. Detailed field logging was done on the exposed Whitehill and Collingham formations as well as a possible conventional sandstone (turbidite) reservoir, the Ripon Formation, along road cuttings of the Ecca Pass. Palaeocurrent data, jointing directions and fossil material were also documented. Samples were analysed for mineralogy, porosity, permeability, and total organic carbon content (TOC). The extensively weathered black shales of the Whitehill Formation contain a maximum TOC value of 0.9% and the Collingham Formation shales contain a maximum TOC value of 0.6%. The organic lithic arkose sandstones of the Ripon Formation are classified as ‘tight rock’ with an average porosity of 1% and an average permeability of 0.05 mD. The Whitehill Formation in the southern portion of the Karoo Basin has experienced organic matter loss due to low grade metamorphism as well as burial to extreme depths, thus reducing shale gas potential. The Ripon Formation is an unsuitable conventional reservoir along the southern basin boundary due to extensive cementation and filling of pore spaces.
- Full Text:
- Date Issued: 2015
- Authors: Campbell, Stuart Alexander
- Date: 2015
- Subjects: Hydrocarbon reservoirs -- Ecca Group , Geology, Stratigraphic -- Permian , Paleogeography -- Ecca Group , Shale gas -- Ecca Group , Shale gas reservoirs -- Ecca Group , Ecca Group , Ripon Formation (South Africa) , Collingham Formation (South Africa)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5083 , http://hdl.handle.net/10962/d1018199
- Description: The Karoo Basin of South Africa holds an estimated 906 billion to 11 trillion cubic meters of unconventional shale gas within the shales of the Whitehill and Collingham formations of the Ecca Group. Evaluation of this potential resource has been limited due to the lack of exploration and a scarcity of existing drill core data. In order to circumnavigate this problem this study was undertaken to evaluate the potential target horizons exposed in outcrops along the southern portion of the Karoo Basin, north of Grahamstown in the Eastern Cape Province. Detailed field logging was done on the exposed Whitehill and Collingham formations as well as a possible conventional sandstone (turbidite) reservoir, the Ripon Formation, along road cuttings of the Ecca Pass. Palaeocurrent data, jointing directions and fossil material were also documented. Samples were analysed for mineralogy, porosity, permeability, and total organic carbon content (TOC). The extensively weathered black shales of the Whitehill Formation contain a maximum TOC value of 0.9% and the Collingham Formation shales contain a maximum TOC value of 0.6%. The organic lithic arkose sandstones of the Ripon Formation are classified as ‘tight rock’ with an average porosity of 1% and an average permeability of 0.05 mD. The Whitehill Formation in the southern portion of the Karoo Basin has experienced organic matter loss due to low grade metamorphism as well as burial to extreme depths, thus reducing shale gas potential. The Ripon Formation is an unsuitable conventional reservoir along the southern basin boundary due to extensive cementation and filling of pore spaces.
- Full Text:
- Date Issued: 2015
NGOs and the depoliticisation of development : the case of GADRA education in Grahamstown
- Authors: Nqaba, Patronella Pinky
- Date: 2015
- Subjects: GADRA Education (Grahamstown, South Africa) , Non-governmental organizations -- South Africa -- Grahamstown , Non-governmental organizations -- Political aspects , Education -- South Africa -- History , Right to education -- South Africa , Educational change -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2890 , http://hdl.handle.net/10962/d1017865
- Description: Non-governmental organisations (NGOs) have been criticised for depoliticising development through focusing on alleviating suffering rather than on addressing the root causes of poverty and underdevelopment. This research explores whether and how NGOs can act in ways that do not depoliticise development. The research focuses on education NGOs and in particular on the NGO GADRA education in Grahamstown, South Africa, to provide insights into ways in which politically conscious leadership of NGOs attempt to deal with the contradictions that are inherent in this field of work. This research provides a brief history of the South African Education system as a means to set a basis for the discussion of the role of education NGOs in the country. Furthermore it looks at the work that is done by GADRA education in the Grahamstown community. The thesis makes the argument that education NGOs can act in ways that do not depoliticise development because by providing access to education for people who are structurally excluded from education, they contribute to shifting power. This research found that although the leadership of GADRA Education acknowledge that they are confronted with great challenges in terms of how to bring about changes in the education system, they are hopeful that advocating for quality education will bring about the potential for the disruption of power relations as they exist between the state organs and the public.
- Full Text:
- Date Issued: 2015
- Authors: Nqaba, Patronella Pinky
- Date: 2015
- Subjects: GADRA Education (Grahamstown, South Africa) , Non-governmental organizations -- South Africa -- Grahamstown , Non-governmental organizations -- Political aspects , Education -- South Africa -- History , Right to education -- South Africa , Educational change -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2890 , http://hdl.handle.net/10962/d1017865
- Description: Non-governmental organisations (NGOs) have been criticised for depoliticising development through focusing on alleviating suffering rather than on addressing the root causes of poverty and underdevelopment. This research explores whether and how NGOs can act in ways that do not depoliticise development. The research focuses on education NGOs and in particular on the NGO GADRA education in Grahamstown, South Africa, to provide insights into ways in which politically conscious leadership of NGOs attempt to deal with the contradictions that are inherent in this field of work. This research provides a brief history of the South African Education system as a means to set a basis for the discussion of the role of education NGOs in the country. Furthermore it looks at the work that is done by GADRA education in the Grahamstown community. The thesis makes the argument that education NGOs can act in ways that do not depoliticise development because by providing access to education for people who are structurally excluded from education, they contribute to shifting power. This research found that although the leadership of GADRA Education acknowledge that they are confronted with great challenges in terms of how to bring about changes in the education system, they are hopeful that advocating for quality education will bring about the potential for the disruption of power relations as they exist between the state organs and the public.
- Full Text:
- Date Issued: 2015
The role of civil society in advancing education rights : the case of Gadra Education, Grahamstown, South Africa
- Authors: Msindo, Esteri Makotore
- Date: 2015
- Subjects: Gadra Education (Grahamstown, South Africa) , Right to education -- South Africa , State departments of education -- South Africa , Educational change -- South Africa , Social justice -- South Africa , Civil society -- South Africa , Social contract
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3392 , http://hdl.handle.net/10962/d1016500
- Description: This thesis has identified and analysed the role of an NGO called Gadra Education in advancing education rights to the less advantaged people of Grahamstown in South Africa. Gadra Education’s role has been identified as twofold. Firstly as an educational NGO, Gadra Education’s initiatives directly impact on the lives of the less economically and socially privileged learners who, due to their previous learning environment in state schools, do not achieve academic results that ensure entry into tertiary level. Secondly its role is identified in its nature as an organisation that emerged due to the deficiencies in the state schooling system. It therefore stands de facto as a critical institution for critique of the state’s education system. The thesis concludes that without confronting the Department of Education or collaborating with it, Gadra Education offers a significant alternative approach which can potentially influence the state to improve the state schooling system. Its strategy of non-confrontation to the state, informal and non-corporatist is advantageous as an NGO that focuses on the actual provision of education. It focuses on instilling Ubuntu values of sharing and giving that are of critical significance in teaching and learning. The context of the thesis is located broadly within socio-economic rights and specifically on education rights. In South Africa where the state has not adequately met the educational obligations for the economically and socially less privileged citizens, the emergence of educational NGOs that focus on providing education to the poor is of vital importance. Although other NGOs that confront the state are important in pushing the state to deliver especially on school infrastructure, teacher deployment and other educational challenges, Gadra Education model ensures academic success for the learner. Lessons can be drawn from Gadra Education which can be potentially useful to state schools and other NGOs that seek to advance education rights to disadvantaged communities.
- Full Text:
- Date Issued: 2015
- Authors: Msindo, Esteri Makotore
- Date: 2015
- Subjects: Gadra Education (Grahamstown, South Africa) , Right to education -- South Africa , State departments of education -- South Africa , Educational change -- South Africa , Social justice -- South Africa , Civil society -- South Africa , Social contract
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3392 , http://hdl.handle.net/10962/d1016500
- Description: This thesis has identified and analysed the role of an NGO called Gadra Education in advancing education rights to the less advantaged people of Grahamstown in South Africa. Gadra Education’s role has been identified as twofold. Firstly as an educational NGO, Gadra Education’s initiatives directly impact on the lives of the less economically and socially privileged learners who, due to their previous learning environment in state schools, do not achieve academic results that ensure entry into tertiary level. Secondly its role is identified in its nature as an organisation that emerged due to the deficiencies in the state schooling system. It therefore stands de facto as a critical institution for critique of the state’s education system. The thesis concludes that without confronting the Department of Education or collaborating with it, Gadra Education offers a significant alternative approach which can potentially influence the state to improve the state schooling system. Its strategy of non-confrontation to the state, informal and non-corporatist is advantageous as an NGO that focuses on the actual provision of education. It focuses on instilling Ubuntu values of sharing and giving that are of critical significance in teaching and learning. The context of the thesis is located broadly within socio-economic rights and specifically on education rights. In South Africa where the state has not adequately met the educational obligations for the economically and socially less privileged citizens, the emergence of educational NGOs that focus on providing education to the poor is of vital importance. Although other NGOs that confront the state are important in pushing the state to deliver especially on school infrastructure, teacher deployment and other educational challenges, Gadra Education model ensures academic success for the learner. Lessons can be drawn from Gadra Education which can be potentially useful to state schools and other NGOs that seek to advance education rights to disadvantaged communities.
- Full Text:
- Date Issued: 2015
The effects of labour law on small firms in South Africa : perceptions of employers in the hospitality sector in Pretoria, Gauteng
- Authors: MacNeill, Jessica Dawn
- Date: 2015
- Subjects: Labor laws and legislation -- South Africa , Small business -- South Africa -- Pretoria , Small business -- South Africa -- Pretoria -- Personnel management , Hospitality industry -- South Africa -- Pretoria -- Personnel management , Manpower policy -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3405 , http://hdl.handle.net/10962/d1018934
- Description: The South African government has attempted to find a balance of interests between the employer and the employee by the introduction of the Labour Relations Act in 1995 and the Basic Conditions of Employment Act in 1997. It is critical to the health of the South African economy that these labour laws do not impact small businesses to the extent that the Gross Domestic Product of the country is negatively affected. There are conflicting reports as to how these labour laws affect small businesses. It is therefore important for government to be able to understand, define and measure the impact of its labour laws on small businesses, in order for it to strategise corrective measures, which may include reconsidering the application of the legislative directive, regulated flexibility, if required. The study was limited in the sense that it was solely based on evidence collected from employers. An interpretivist approach was applied as a research methodology to data collected through in-depth interviews. The main findings of the empirical analysis demonstrate that labour legislation does not heavily impact small firms. It was thus determined that extensive measures were not needed with regard to correcting the framework of regulated flexibility.
- Full Text:
- Date Issued: 2015
- Authors: MacNeill, Jessica Dawn
- Date: 2015
- Subjects: Labor laws and legislation -- South Africa , Small business -- South Africa -- Pretoria , Small business -- South Africa -- Pretoria -- Personnel management , Hospitality industry -- South Africa -- Pretoria -- Personnel management , Manpower policy -- South Africa
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3405 , http://hdl.handle.net/10962/d1018934
- Description: The South African government has attempted to find a balance of interests between the employer and the employee by the introduction of the Labour Relations Act in 1995 and the Basic Conditions of Employment Act in 1997. It is critical to the health of the South African economy that these labour laws do not impact small businesses to the extent that the Gross Domestic Product of the country is negatively affected. There are conflicting reports as to how these labour laws affect small businesses. It is therefore important for government to be able to understand, define and measure the impact of its labour laws on small businesses, in order for it to strategise corrective measures, which may include reconsidering the application of the legislative directive, regulated flexibility, if required. The study was limited in the sense that it was solely based on evidence collected from employers. An interpretivist approach was applied as a research methodology to data collected through in-depth interviews. The main findings of the empirical analysis demonstrate that labour legislation does not heavily impact small firms. It was thus determined that extensive measures were not needed with regard to correcting the framework of regulated flexibility.
- Full Text:
- Date Issued: 2015
Performing whiteness; representing otherness : Hugh Tracey and African music
- Authors: Coetzee, Paulette June
- Date: 2015
- Subjects: Tracey, Hugh , Music -- Africa , International Library of African Music , Ethnomusicology -- Africa , Ethnomusicologists -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2327 , http://hdl.handle.net/10962/d1016502
- Description: This thesis provides a critical study of texts associated with Hugh Tracey (1903–1977). Tracey is well-known for his work in African music studies, particularly for his major contribution to the recorded archive of musical sound in sub-Saharan Africa and his founding of the International Library of African Music (ILAM) in 1954. My reading of him is informed by a postcolonial perspective, whiteness studies and African scholarship on ways in which constructions of African identity and tradition have been shaped by the colonial archive. In my view, Tracey was part of a mid-twentieth century movement which sought to marshal positive representations of traditional African culture in the interest of maintaining and strengthening colonial rule. While his recording project may have fostered inclusion through creating spaces for indigenous musicians to be heard, it also functioned to promote racist exclusion in the manner of its production, distribution and claims to expertise. Moreover, his initial strategy for ILAM’s sustainability targeted colonial government and industry as primary clients, with the promise that promoting traditional music as a means of entertainment and self-expression for black subjects and workers would ease administration and reduce conflict. I believe that it is important to acknowledge and interrogate the problematic racial attitudes and practices associated with the history of Tracey’s archive – not to undermine its significance in any way but to allow it to be better understood and used more productively in the future.
- Full Text:
- Date Issued: 2015
- Authors: Coetzee, Paulette June
- Date: 2015
- Subjects: Tracey, Hugh , Music -- Africa , International Library of African Music , Ethnomusicology -- Africa , Ethnomusicologists -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2327 , http://hdl.handle.net/10962/d1016502
- Description: This thesis provides a critical study of texts associated with Hugh Tracey (1903–1977). Tracey is well-known for his work in African music studies, particularly for his major contribution to the recorded archive of musical sound in sub-Saharan Africa and his founding of the International Library of African Music (ILAM) in 1954. My reading of him is informed by a postcolonial perspective, whiteness studies and African scholarship on ways in which constructions of African identity and tradition have been shaped by the colonial archive. In my view, Tracey was part of a mid-twentieth century movement which sought to marshal positive representations of traditional African culture in the interest of maintaining and strengthening colonial rule. While his recording project may have fostered inclusion through creating spaces for indigenous musicians to be heard, it also functioned to promote racist exclusion in the manner of its production, distribution and claims to expertise. Moreover, his initial strategy for ILAM’s sustainability targeted colonial government and industry as primary clients, with the promise that promoting traditional music as a means of entertainment and self-expression for black subjects and workers would ease administration and reduce conflict. I believe that it is important to acknowledge and interrogate the problematic racial attitudes and practices associated with the history of Tracey’s archive – not to undermine its significance in any way but to allow it to be better understood and used more productively in the future.
- Full Text:
- Date Issued: 2015
Structure of the nucleus ¹¹⁴Sn using gamma-ray coincidence data
- Authors: Oates, Sean Benjamin
- Date: 2015
- Subjects: High spin physics , Nuclear structure , Nuclear shell theory , Neutron counters , Decay schemes (Radioactivity) , Coincidence circuits , Collective excitations , Anisotropy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5562 , http://hdl.handle.net/10962/d1019870
- Full Text:
- Date Issued: 2015
- Authors: Oates, Sean Benjamin
- Date: 2015
- Subjects: High spin physics , Nuclear structure , Nuclear shell theory , Neutron counters , Decay schemes (Radioactivity) , Coincidence circuits , Collective excitations , Anisotropy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5562 , http://hdl.handle.net/10962/d1019870
- Full Text:
- Date Issued: 2015
The interrelationships between foreign direct investment and economic growth in Africa
- Authors: Bolani, Lindelwa Mandisa
- Date: 2015
- Subjects: Investments, Foreign -- Africa , Economic development -- Africa , Africa -- Economic conditions -- 1960- , Africa -- Foreign economic relations , Gross domestic product -- Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1123 , http://hdl.handle.net/10962/d1019885
- Description: There has been a long search for the keys to development and economic growth in Africa. This study investigates the relationship between FDI and economic growth over the period 2000-2012 using data from 48 African countries. On the aggregate regional level FDI and economic growth were found to be positively correlated during this period. Using panel data econometric techniques and the Panel Granger Causality test, results revealed that a bi-directional causality relationship existed between FDI and GDP. Thus, the results suggest that GDP is a requirement for increased investment, and at the same time is the result of increased foreign investment. Thus, the conclusion is that African policy makers are justified in increasing their attempts to create an attractive business environment for foreign investors, as it is beneficial for economic growth.
- Full Text:
- Date Issued: 2015
- Authors: Bolani, Lindelwa Mandisa
- Date: 2015
- Subjects: Investments, Foreign -- Africa , Economic development -- Africa , Africa -- Economic conditions -- 1960- , Africa -- Foreign economic relations , Gross domestic product -- Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1123 , http://hdl.handle.net/10962/d1019885
- Description: There has been a long search for the keys to development and economic growth in Africa. This study investigates the relationship between FDI and economic growth over the period 2000-2012 using data from 48 African countries. On the aggregate regional level FDI and economic growth were found to be positively correlated during this period. Using panel data econometric techniques and the Panel Granger Causality test, results revealed that a bi-directional causality relationship existed between FDI and GDP. Thus, the results suggest that GDP is a requirement for increased investment, and at the same time is the result of increased foreign investment. Thus, the conclusion is that African policy makers are justified in increasing their attempts to create an attractive business environment for foreign investors, as it is beneficial for economic growth.
- Full Text:
- Date Issued: 2015
Link between ghost artefacts, source suppression and incomplete calibration sky models
- Authors: Nunhokee, Chuneeta Devi
- Date: 2015
- Subjects: Interferometry , Calibration
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5556 , http://hdl.handle.net/10962/d1017900
- Description: Calibration is a fundamental step towards producing radio interferometric images. However, naive calibration produces calibration artefacts, in the guise of spurious emission, buried in the thermal noise. This work investigates these calibration artefacts, henceforth referred to as “ghosts”. A 21 cm observation with the Westerbork Synthesis Radio Telescope yielded similar ghost sources, and it was anticipated that they were due to calibrating with incomplete sky models. An analytical ghost distribution of a two-source scenario is derived to substantiate this theory and to seek answers to the related bewildering features (regular ghost pattern, points spread function-like sidelobes, independent of model flux). The theoretically predicted ghost distribution qualitatively matches with the observational ones and shows high dependence on the array geometry. The theory draws the conclusion that both the ghost phenomenon and suppression of the unmodelled flux have the same root cause. In addition, the suppression of the unmodelled flux is studied as functions of unmodelled flux, differential gain solution interval and the number of sources subjected to direction-dependent gains. These studies summarise that the suppression rate is constant irrespective of the degree of incompleteness of the calibration sky model. In the presence of a direction-dependent effect, the suppression drastically increases; however, this increase can be compensated for by using longer solution intervals.
- Full Text:
- Date Issued: 2015
- Authors: Nunhokee, Chuneeta Devi
- Date: 2015
- Subjects: Interferometry , Calibration
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5556 , http://hdl.handle.net/10962/d1017900
- Description: Calibration is a fundamental step towards producing radio interferometric images. However, naive calibration produces calibration artefacts, in the guise of spurious emission, buried in the thermal noise. This work investigates these calibration artefacts, henceforth referred to as “ghosts”. A 21 cm observation with the Westerbork Synthesis Radio Telescope yielded similar ghost sources, and it was anticipated that they were due to calibrating with incomplete sky models. An analytical ghost distribution of a two-source scenario is derived to substantiate this theory and to seek answers to the related bewildering features (regular ghost pattern, points spread function-like sidelobes, independent of model flux). The theoretically predicted ghost distribution qualitatively matches with the observational ones and shows high dependence on the array geometry. The theory draws the conclusion that both the ghost phenomenon and suppression of the unmodelled flux have the same root cause. In addition, the suppression of the unmodelled flux is studied as functions of unmodelled flux, differential gain solution interval and the number of sources subjected to direction-dependent gains. These studies summarise that the suppression rate is constant irrespective of the degree of incompleteness of the calibration sky model. In the presence of a direction-dependent effect, the suppression drastically increases; however, this increase can be compensated for by using longer solution intervals.
- Full Text:
- Date Issued: 2015