A study of spherical solutions in chameleon scalar-tensor theories
- Authors: Mohapi, Neo
- Date: 2014
- Subjects: Scalar field theory , Equivalence principle (Physics) , General relativity (Physics) , Bosons , Dark energy (Astronomy) , Galactic dynamics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5428 , http://hdl.handle.net/10962/d1013315
- Description: The equivalence principle has proven to be central to theories of gravity, with General Relativity being the simplest and most elegant theory to embody the principle. Most alternative theories of gravity struggle to satisfy the principle and still be distinct from GR. Extensions of cosmological and quantum theories question the irrefutably of the equivalence at every scale. The possibility of an equivalence principle violation at galactic scales would be an exciting prospect. In this thesis, we will carefully examine the equivalence principle through the study of chameleon scalar-tensor theories, this will include solutions for hypothetical stars known as boson stars. Such theories find varied application, especially in cosmology, where they model dark energy and inflation. The AWE hypothesis, is an instance of this. It is a nonuniversally coupled model in which violations of the equivalence principle on galactic scales may be apparent. We investigate spherically symmetric and static solutions within the framework of this theory. The constraints obtained from galactic rotation curves results in values of the couplings that show no significant violation of the equivalence principle or values consistent with a theory of dark energy
- Full Text:
- Date Issued: 2014
- Authors: Mohapi, Neo
- Date: 2014
- Subjects: Scalar field theory , Equivalence principle (Physics) , General relativity (Physics) , Bosons , Dark energy (Astronomy) , Galactic dynamics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5428 , http://hdl.handle.net/10962/d1013315
- Description: The equivalence principle has proven to be central to theories of gravity, with General Relativity being the simplest and most elegant theory to embody the principle. Most alternative theories of gravity struggle to satisfy the principle and still be distinct from GR. Extensions of cosmological and quantum theories question the irrefutably of the equivalence at every scale. The possibility of an equivalence principle violation at galactic scales would be an exciting prospect. In this thesis, we will carefully examine the equivalence principle through the study of chameleon scalar-tensor theories, this will include solutions for hypothetical stars known as boson stars. Such theories find varied application, especially in cosmology, where they model dark energy and inflation. The AWE hypothesis, is an instance of this. It is a nonuniversally coupled model in which violations of the equivalence principle on galactic scales may be apparent. We investigate spherically symmetric and static solutions within the framework of this theory. The constraints obtained from galactic rotation curves results in values of the couplings that show no significant violation of the equivalence principle or values consistent with a theory of dark energy
- Full Text:
- Date Issued: 2014
A study of the Consumption Capital Asset Pricing Model's appilcability across four countries
- Spurway, Kayleigh Fay Nanette
- Authors: Spurway, Kayleigh Fay Nanette
- Date: 2014
- Subjects: Econometric models , Capital assets pricing model , Investments , Econometric models -- Germany , Econometric models -- South Africa , Econometric models -- Great Britain , Econometric models -- United States
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1095 , http://hdl.handle.net/10962/d1013016
- Description: Historically, the Consumption Capital Asset Pricing Method (C-CAPM) has performed poorly in that estimated parameters are implausible, model restrictions are often rejected and inferences appear to be very sensitive to the choice of economic agents' preferences. In this study, we estimate and test the C-CAPM with Constant Relative Risk Aversion (CRRA) using time series data from Germany, South Africa, Britain and America during relatively short time periods with the latest available data sets. Hansen's GMM approach is applied to estimate the parameters arising from this model. In general, estimated parameters fall outside the bounds specified by Lund & Engsted (1996) and Cuthbertson & Nitzsche (2004), even though the models are not rejected by the J-test and are associated with relatively small minimum distances.
- Full Text:
- Date Issued: 2014
- Authors: Spurway, Kayleigh Fay Nanette
- Date: 2014
- Subjects: Econometric models , Capital assets pricing model , Investments , Econometric models -- Germany , Econometric models -- South Africa , Econometric models -- Great Britain , Econometric models -- United States
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1095 , http://hdl.handle.net/10962/d1013016
- Description: Historically, the Consumption Capital Asset Pricing Method (C-CAPM) has performed poorly in that estimated parameters are implausible, model restrictions are often rejected and inferences appear to be very sensitive to the choice of economic agents' preferences. In this study, we estimate and test the C-CAPM with Constant Relative Risk Aversion (CRRA) using time series data from Germany, South Africa, Britain and America during relatively short time periods with the latest available data sets. Hansen's GMM approach is applied to estimate the parameters arising from this model. In general, estimated parameters fall outside the bounds specified by Lund & Engsted (1996) and Cuthbertson & Nitzsche (2004), even though the models are not rejected by the J-test and are associated with relatively small minimum distances.
- Full Text:
- Date Issued: 2014
A study of the corporate social investment distribution and spending by selected corporates in the Eastern Cape
- Authors: Tetyana, Sakhiwo
- Date: 2014
- Subjects: Investments -- Moral and ethical aspects -- South Africa -- Eastern Cape , Sustainable development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9203 , http://hdl.handle.net/10948/d1020423
- Description: Corporate Social Investment (CSI) presents a platform for the business sector in South Africa to respond to challenges facing the Eastern Cape. Challenges facing this province are well documented, and it is important to measure and quantify how the business sector in South Africa currently contributes towards addressing those challenges. The Eastern Cape remains by and large undeveloped, with economic activity well below economic potential. Currently, economic activity is concentrated in Port Elizabeth, East London and Mthatha. Notwithstanding economic growth, high levels of unemployment and poverty persist, particularly in the rural areas where two-thirds of the population reside. The research study purposely sampled the top 30 companies from the top 100 listed in Trialogue. A total of 14 questionnaires were completed and returned by respondents. Five CSI managers were randomly selected from the 30 companies for in-depth interviews. The purpose of this exercise was to solicit further views to enable substantive triangulation of data from other sources. The research reveals that corporate groups in South Africa use different but complementary models and strategies in contributing towards poverty reduction. Education, particularly support for secondary school technology and science tuition, and also early childhood development (ECD), constitute key intervention areas by corporations in the Eastern Cape. This is closely followed by economic inclusion or enterprise development. There is no demonstrable evidence that corporate social investment in South Africa is informed by a coherent theoretical framework. The study revealed that education receives the largest share of CSI budgets in the Eastern Cape. Within education, mathematics and science is the most supported sub-programme focus area. This is followed by higher education which is also a preferred sub-programme focus area. A total of 40 percent of CSI spending has been channeled towards rural areas and towns in the former Transkei area. The ‘Mandela factor’ also plays an influential role in thedistribution of CSI spending, especially in the rural areas of the former Transkei. Donations ‘in kind’ are mostly distributed in urban areas.
- Full Text:
- Date Issued: 2014
- Authors: Tetyana, Sakhiwo
- Date: 2014
- Subjects: Investments -- Moral and ethical aspects -- South Africa -- Eastern Cape , Sustainable development -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9203 , http://hdl.handle.net/10948/d1020423
- Description: Corporate Social Investment (CSI) presents a platform for the business sector in South Africa to respond to challenges facing the Eastern Cape. Challenges facing this province are well documented, and it is important to measure and quantify how the business sector in South Africa currently contributes towards addressing those challenges. The Eastern Cape remains by and large undeveloped, with economic activity well below economic potential. Currently, economic activity is concentrated in Port Elizabeth, East London and Mthatha. Notwithstanding economic growth, high levels of unemployment and poverty persist, particularly in the rural areas where two-thirds of the population reside. The research study purposely sampled the top 30 companies from the top 100 listed in Trialogue. A total of 14 questionnaires were completed and returned by respondents. Five CSI managers were randomly selected from the 30 companies for in-depth interviews. The purpose of this exercise was to solicit further views to enable substantive triangulation of data from other sources. The research reveals that corporate groups in South Africa use different but complementary models and strategies in contributing towards poverty reduction. Education, particularly support for secondary school technology and science tuition, and also early childhood development (ECD), constitute key intervention areas by corporations in the Eastern Cape. This is closely followed by economic inclusion or enterprise development. There is no demonstrable evidence that corporate social investment in South Africa is informed by a coherent theoretical framework. The study revealed that education receives the largest share of CSI budgets in the Eastern Cape. Within education, mathematics and science is the most supported sub-programme focus area. This is followed by higher education which is also a preferred sub-programme focus area. A total of 40 percent of CSI spending has been channeled towards rural areas and towns in the former Transkei area. The ‘Mandela factor’ also plays an influential role in thedistribution of CSI spending, especially in the rural areas of the former Transkei. Donations ‘in kind’ are mostly distributed in urban areas.
- Full Text:
- Date Issued: 2014
A study of the impact of the St. Mary's Development and Care Centre on communities in Grahamstown
- Authors: Booth, Kaylene Lucinda
- Date: 2014
- Subjects: Community-based social services -- South Africa -- Grahamstown , Community development -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9193 , http://hdl.handle.net/10948/d1020369
- Description: The study is made in an attempt to evaluate a Non-Profit Organisation established 30 years ago. The organisation is called The St. Mary’s Development and Care Centre. This centre, amongst others, was established in 1982 by a true humanitarian, Mrs Thelma Henderson, and has since had more than 2250 children and lots more families in its care. The research aims to explore and evaluate the impact that the centre has had on the families and communities in Grahamstown. The evaluation is done as part of the current manager’s strategy to assess the strengths of the organisation and to build on the efficacy of the organisation. The researcher understands impact as any change whether positive or negative. This, from a social science perspective, is experienced by the person on a personal level and the effects in different families cannot be measured with a universal measure. Theory proves that because people are at varying levels of development, they therefore experience change and thus impact, differently. With the use of the grounded theory method comprising of systematic, inductive and comparative approaches for conducting inquiry for the purpose of constructing theory (Bryant & Charmaz 2007: 1) the research found that people have experienced change at different levels. This information, triangulated against previous research, validated the claims that child sponsorship at an NGO level indeed has benefits for the children involved in their programs. Therefore this evaluation paper draws the conclusion through similarities found and qualitative personal views that the St. Mary’s Development and Care Centre has indeed had an impact on the Grahamstown community.
- Full Text:
- Date Issued: 2014
- Authors: Booth, Kaylene Lucinda
- Date: 2014
- Subjects: Community-based social services -- South Africa -- Grahamstown , Community development -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9193 , http://hdl.handle.net/10948/d1020369
- Description: The study is made in an attempt to evaluate a Non-Profit Organisation established 30 years ago. The organisation is called The St. Mary’s Development and Care Centre. This centre, amongst others, was established in 1982 by a true humanitarian, Mrs Thelma Henderson, and has since had more than 2250 children and lots more families in its care. The research aims to explore and evaluate the impact that the centre has had on the families and communities in Grahamstown. The evaluation is done as part of the current manager’s strategy to assess the strengths of the organisation and to build on the efficacy of the organisation. The researcher understands impact as any change whether positive or negative. This, from a social science perspective, is experienced by the person on a personal level and the effects in different families cannot be measured with a universal measure. Theory proves that because people are at varying levels of development, they therefore experience change and thus impact, differently. With the use of the grounded theory method comprising of systematic, inductive and comparative approaches for conducting inquiry for the purpose of constructing theory (Bryant & Charmaz 2007: 1) the research found that people have experienced change at different levels. This information, triangulated against previous research, validated the claims that child sponsorship at an NGO level indeed has benefits for the children involved in their programs. Therefore this evaluation paper draws the conclusion through similarities found and qualitative personal views that the St. Mary’s Development and Care Centre has indeed had an impact on the Grahamstown community.
- Full Text:
- Date Issued: 2014
A study of the reintegration of female former child soldiers in Gulu District, northern Uganda
- Authors: Bertelsen, Anna
- Date: 2014
- Subjects: Women soldiers -- Uganda -- Gulu District , Child soldiers -- Uganda -- Gulu District , Patriarchy -- Uganda -- Gulu District
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: vital:8324 , http://hdl.handle.net/10948/d1020192
- Description: This research explores the perceptions and experiences of female former child soldiers in regard to their reintegration within the community of Gulu District, northern Uganda. In many societies women are generally excluded due to prevailing patriarchal hegemonies, with northern Uganda being no exception. Moreover, former child soldiers are commonly marginalized and discriminated against because members of communities commonly believe that they should be punished for the perceived atrocities that they allegedly committed during times of conflict, rather than be reintegrated into society. In this regard female former child soldiers can be identified as a particularly vulnerable and marginalized group. Therefore, it can be suggested that although the distinction between traditional gender roles has been eroded during times of armed conflict, there is still widespread evidence that women are largely overlooked and disregarded in the process of peace building. In order to explore the perceptions and experiences of former female child soldiers, a qualitative case study method was utilized based on in-depth face to face interviews with women from Gulu District, northern Uganda. The findings of this study indicate that, even though these women went through considerable hardships, all of them displayed a strong sense of resilience. Many of them had taken on the role as active change agents in their own lives and provided an array of suggestions on how their situation could be improved. The major themes constructed from the study include: challenges facing returnees; facilitating factors for returnees and suggestions on improved reintegration. Based on these findings a number of recommendations emerged. The recommendations are presented in order to assist organizations and other stakeholders involved in reintegration of child soldiers in northern Uganda and elsewhere in the world. Apart from providing information to the existing body of research, future areas of proposed research are also outlined.
- Full Text:
- Date Issued: 2014
- Authors: Bertelsen, Anna
- Date: 2014
- Subjects: Women soldiers -- Uganda -- Gulu District , Child soldiers -- Uganda -- Gulu District , Patriarchy -- Uganda -- Gulu District
- Language: English
- Type: Thesis , Masters , MPhil
- Identifier: vital:8324 , http://hdl.handle.net/10948/d1020192
- Description: This research explores the perceptions and experiences of female former child soldiers in regard to their reintegration within the community of Gulu District, northern Uganda. In many societies women are generally excluded due to prevailing patriarchal hegemonies, with northern Uganda being no exception. Moreover, former child soldiers are commonly marginalized and discriminated against because members of communities commonly believe that they should be punished for the perceived atrocities that they allegedly committed during times of conflict, rather than be reintegrated into society. In this regard female former child soldiers can be identified as a particularly vulnerable and marginalized group. Therefore, it can be suggested that although the distinction between traditional gender roles has been eroded during times of armed conflict, there is still widespread evidence that women are largely overlooked and disregarded in the process of peace building. In order to explore the perceptions and experiences of former female child soldiers, a qualitative case study method was utilized based on in-depth face to face interviews with women from Gulu District, northern Uganda. The findings of this study indicate that, even though these women went through considerable hardships, all of them displayed a strong sense of resilience. Many of them had taken on the role as active change agents in their own lives and provided an array of suggestions on how their situation could be improved. The major themes constructed from the study include: challenges facing returnees; facilitating factors for returnees and suggestions on improved reintegration. Based on these findings a number of recommendations emerged. The recommendations are presented in order to assist organizations and other stakeholders involved in reintegration of child soldiers in northern Uganda and elsewhere in the world. Apart from providing information to the existing body of research, future areas of proposed research are also outlined.
- Full Text:
- Date Issued: 2014
A study on the application technology of the sterile insect technique, with focus on false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), a pest of citrus in South Africa
- Authors: Nepgen, Eugene Stephan
- Date: 2014
- Subjects: Cryptophlebia leucotreta , Citrus -- Diseases and pests -- Control -- South Africa , Insect pests -- Control -- South Africa , Insect sterilization
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5879 , http://hdl.handle.net/10962/d1013199
- Description: False codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is considered the most important indigenous pest of citrus in southern Africa. Major concerns such as progressive insecticidal resistance, the negative impact of insecticides on the environment, as well as the influence of consumers opposed to chemical residues on fruit, created opportunities for biological control methods such as Sterile Insect Technology (SIT). This technology is now established in the Western and Eastern Cape provinces of South Africa as an effective, sustainable alternative to conventional FCM control methods. Due to the prevalence of the pest in all citrus producing areas of South Africa, potential for SIT to expand is enormous. Success of an SIT programme is highly dependent on efficient application of the technology to achieve its objectives in a timeous manner. The aim of this study was to advance the application of SIT for control of FCM on citrus in South Africa, by investigating the effect of certain critical stages in the process. The effect of long-distance transportation on fitness of irradiated FCM was determined, showing reduced performance with cold-immobilized transport. A significant decrease in flight ability and longevity of irradiated FCM was found, although critically, realized fecundity was not affected. The effect of two different insecticides in the pyrethroid and organophosphate chemical groups were investigated for their residual effect on mortality of released irradiated FCM, to determine if these pest control programmes could be integrated. Both chlorpyrifos and tau-fluvalinate were effective in killing irradiated FCM for a number of days after application, after which degradation of the active ingredient rendered it harmless. This effect was found to be similar for irradiated and non-irradiated males, consequently ratios of sterile : wild male FCM should be retained regardless of whether sprays are applied or not. The modes for release of sterile FCM in an SIT programme were investigated. Efficacy of ground and aerial release platforms were tested by evaluating the recovery of released irradiated male FCM in these orchards. More irradiated FCM were recovered in orchards released from the ground compared to air. However, an economic analysis of both methods shows application of irradiated insects over a large geographical area is more cost-effective by air. Depending on the terrain and size of the target area, a combination of both methods is ideal for application of SIT for control of FCM in citrus. Development of application technology for advance of the programme is discussed and recommendations for future research and development are offered.
- Full Text:
- Date Issued: 2014
- Authors: Nepgen, Eugene Stephan
- Date: 2014
- Subjects: Cryptophlebia leucotreta , Citrus -- Diseases and pests -- Control -- South Africa , Insect pests -- Control -- South Africa , Insect sterilization
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5879 , http://hdl.handle.net/10962/d1013199
- Description: False codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is considered the most important indigenous pest of citrus in southern Africa. Major concerns such as progressive insecticidal resistance, the negative impact of insecticides on the environment, as well as the influence of consumers opposed to chemical residues on fruit, created opportunities for biological control methods such as Sterile Insect Technology (SIT). This technology is now established in the Western and Eastern Cape provinces of South Africa as an effective, sustainable alternative to conventional FCM control methods. Due to the prevalence of the pest in all citrus producing areas of South Africa, potential for SIT to expand is enormous. Success of an SIT programme is highly dependent on efficient application of the technology to achieve its objectives in a timeous manner. The aim of this study was to advance the application of SIT for control of FCM on citrus in South Africa, by investigating the effect of certain critical stages in the process. The effect of long-distance transportation on fitness of irradiated FCM was determined, showing reduced performance with cold-immobilized transport. A significant decrease in flight ability and longevity of irradiated FCM was found, although critically, realized fecundity was not affected. The effect of two different insecticides in the pyrethroid and organophosphate chemical groups were investigated for their residual effect on mortality of released irradiated FCM, to determine if these pest control programmes could be integrated. Both chlorpyrifos and tau-fluvalinate were effective in killing irradiated FCM for a number of days after application, after which degradation of the active ingredient rendered it harmless. This effect was found to be similar for irradiated and non-irradiated males, consequently ratios of sterile : wild male FCM should be retained regardless of whether sprays are applied or not. The modes for release of sterile FCM in an SIT programme were investigated. Efficacy of ground and aerial release platforms were tested by evaluating the recovery of released irradiated male FCM in these orchards. More irradiated FCM were recovered in orchards released from the ground compared to air. However, an economic analysis of both methods shows application of irradiated insects over a large geographical area is more cost-effective by air. Depending on the terrain and size of the target area, a combination of both methods is ideal for application of SIT for control of FCM in citrus. Development of application technology for advance of the programme is discussed and recommendations for future research and development are offered.
- Full Text:
- Date Issued: 2014
A survey of youth development projects in the Department of Social Development in the province of the Eastern Cape: a management perspective
- Dliwayo, Mziwodumo Archibald
- Authors: Dliwayo, Mziwodumo Archibald
- Date: 2014
- Subjects: Youth in development -- South Africa -- Eastern Cape , Economic development projects , Youth -- Services for
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: http://hdl.handle.net/10948/4429 , vital:20600
- Description: The objective of this research is to establish how non-adherence of Amathole District development projects to the Department of Social Development’s Community Development Systems and Operational Manual has contributed to failure of these projects. The background to this research lies in the deliberate policy efforts of the post 1994 democratic dispensation in South Africa to drive development through community-based development approaches. Explicitly pro-poor public policies, development plans and fiscal frameworks were anchored on the concept of community empowerment. The Reconstruction and Development Programme was the first such policy and strategy framework that sought to enshrine the principles of community empowerment and participation. As such, Provincial and Local government are often seen as key strategic drivers of community empowerment initiatives and interventions. South Africa’s governance model is still evolving, but it is clearly committed to local development and service delivery through a decentralised system of government that espouses community involvement. Government strategy has been heavily focused on speed and delivery in order to deal with the historical socio-economic backlogs it inherited. In the focus area of youth development projects, one recognises that poor management has dramatically reduced the effectiveness of many interventions. This research explores how non-adherence of these projects to policy guidelines set out in the Community Development Systems and Operations Manual has contributed to their failure. The research does this by looking at the various management procedures that are supposed to be undertaken during both the initial planning phases and during the subsequent implementation phases of youth development projects. Actual methodologies are compared against this standard. The research is undoubtedly a contribution to the field of strategic management of youth development initiatives which have as their primary intention the reduction of youth unemployment. Research surveys on this topic are limited, and the objective is to enrich the discourse on effective youth projects management practices.
- Full Text:
- Date Issued: 2014
- Authors: Dliwayo, Mziwodumo Archibald
- Date: 2014
- Subjects: Youth in development -- South Africa -- Eastern Cape , Economic development projects , Youth -- Services for
- Language: English
- Type: Thesis , Masters , MPA
- Identifier: http://hdl.handle.net/10948/4429 , vital:20600
- Description: The objective of this research is to establish how non-adherence of Amathole District development projects to the Department of Social Development’s Community Development Systems and Operational Manual has contributed to failure of these projects. The background to this research lies in the deliberate policy efforts of the post 1994 democratic dispensation in South Africa to drive development through community-based development approaches. Explicitly pro-poor public policies, development plans and fiscal frameworks were anchored on the concept of community empowerment. The Reconstruction and Development Programme was the first such policy and strategy framework that sought to enshrine the principles of community empowerment and participation. As such, Provincial and Local government are often seen as key strategic drivers of community empowerment initiatives and interventions. South Africa’s governance model is still evolving, but it is clearly committed to local development and service delivery through a decentralised system of government that espouses community involvement. Government strategy has been heavily focused on speed and delivery in order to deal with the historical socio-economic backlogs it inherited. In the focus area of youth development projects, one recognises that poor management has dramatically reduced the effectiveness of many interventions. This research explores how non-adherence of these projects to policy guidelines set out in the Community Development Systems and Operations Manual has contributed to their failure. The research does this by looking at the various management procedures that are supposed to be undertaken during both the initial planning phases and during the subsequent implementation phases of youth development projects. Actual methodologies are compared against this standard. The research is undoubtedly a contribution to the field of strategic management of youth development initiatives which have as their primary intention the reduction of youth unemployment. Research surveys on this topic are limited, and the objective is to enrich the discourse on effective youth projects management practices.
- Full Text:
- Date Issued: 2014
A sustainability reporting framework for South African Higher Education Institutions
- Authors: Bosire, Samuel Mobisa
- Date: 2014
- Subjects: Sustainable development reporting -- South Africa , Business intelligence -- South Africa , Universities and colleges -- South Africa , Corporate governance -- South Africa
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: vital:8798 , http://hdl.handle.net/10948/d1016126
- Description: Sustainability has gained prominence globally among nations, regions and organisations as a result of factors such as the effects of climate change on the environment, diminishing natural resources and rising population growth with their concomitant impact on economies and social systems. South Africa is a signatory to the United Nations Global Compact (UNGC) that promotes international principles and best practices on sustainable development. Sustainability Reporting is one such best practice. Sustainability Reporting is imperative for good governance and organisations are now expected to support sustainability issues, risks and performance in a balanced and reasonable way. The United Nations and other global bodies have been in the vanguard in promoting guidelines for sustainability reporting with the Global Reporting Initiative (GRI) being the most Prominent Sustainability reporting guideline. The South African Higher Education Institutions generate a number of reports in the course of any given academic year. As has been the case in the global corporate world, failures in governance in some South African universities point to weaknesses in their governance, especially when it comes to oversight of the operations of institutions. Considering this, it is important to critically examine strategic planning processes to understand the aspects that are important for the survival of Higher Education Institutions (HEIs) and therefore they should be regularly and closely monitored. The study begins by exploring literature relating to strategic planning, governance, sustainability reporting practices and Business Intelligence (BI) technologies in Higher Education. The primary objective of the investigation is to propose a sustainability reporting framework for Higher Education Institutions in South Africa. It is argued that with the aid of appropriate BI tools, the proposed Sustainability Reporting framework would be useful in tracking progress in the implementation of strategic plans and at the same time strengthen governance in institutions. The study identified elements of Sustainability Reporting that are important for strategic planning. To develop the proposed framework, an empirical investigation was undertaken. Four online questionnaires were completed and returned by 108 participants comprising of Registrars and Information Managers at 23 South African Higher Education Institutions as well as to Information Managers in selected International Higher Education Institutions and Managers at the Nelson Mandela Metropolitan University (NMMU). The online questionnaires were developed to elicit information to include in the proposed framework. To analyse results, both descriptive and inferential statistics such as Analysis of Variance (ANOVA) were used. Results from the surveys revealed that Higher Education Institutions globally and in South Africa are grappling with the same issues. When it comes to Sustainability Reporting, factors such as information culture and Business Intelligence maturity levels were not found to be very different among the various institutions. In the case study at NMMU, correlational analysis confirmed that variables such as Management buying and the availability of BI reports were positively related to effective strategic planning and vice versa. Similarly, a strong correlation was observed between reporting guidelines and strategic planning. Moreover, the study highlighted the critical role of management and leadership in a university in creating an environment that supports Sustainability Reporting. In conclusion, it was recommended that efforts should be directed at creating awareness and at training staff on aspects that promote sustainability. It is incumbent upon the institution to take advantage of and promote technological tools and techniques to enable the easy flow of data and information in understandable and usable formats to all its stakeholders. Finally, a Framework for Sustainability Reporting for Higher Education Institutions (FSRHEI) and guidelines for implementing Sustainability Reports are proposed.
- Full Text:
- Date Issued: 2014
- Authors: Bosire, Samuel Mobisa
- Date: 2014
- Subjects: Sustainable development reporting -- South Africa , Business intelligence -- South Africa , Universities and colleges -- South Africa , Corporate governance -- South Africa
- Language: English
- Type: Thesis , Doctoral , DBA
- Identifier: vital:8798 , http://hdl.handle.net/10948/d1016126
- Description: Sustainability has gained prominence globally among nations, regions and organisations as a result of factors such as the effects of climate change on the environment, diminishing natural resources and rising population growth with their concomitant impact on economies and social systems. South Africa is a signatory to the United Nations Global Compact (UNGC) that promotes international principles and best practices on sustainable development. Sustainability Reporting is one such best practice. Sustainability Reporting is imperative for good governance and organisations are now expected to support sustainability issues, risks and performance in a balanced and reasonable way. The United Nations and other global bodies have been in the vanguard in promoting guidelines for sustainability reporting with the Global Reporting Initiative (GRI) being the most Prominent Sustainability reporting guideline. The South African Higher Education Institutions generate a number of reports in the course of any given academic year. As has been the case in the global corporate world, failures in governance in some South African universities point to weaknesses in their governance, especially when it comes to oversight of the operations of institutions. Considering this, it is important to critically examine strategic planning processes to understand the aspects that are important for the survival of Higher Education Institutions (HEIs) and therefore they should be regularly and closely monitored. The study begins by exploring literature relating to strategic planning, governance, sustainability reporting practices and Business Intelligence (BI) technologies in Higher Education. The primary objective of the investigation is to propose a sustainability reporting framework for Higher Education Institutions in South Africa. It is argued that with the aid of appropriate BI tools, the proposed Sustainability Reporting framework would be useful in tracking progress in the implementation of strategic plans and at the same time strengthen governance in institutions. The study identified elements of Sustainability Reporting that are important for strategic planning. To develop the proposed framework, an empirical investigation was undertaken. Four online questionnaires were completed and returned by 108 participants comprising of Registrars and Information Managers at 23 South African Higher Education Institutions as well as to Information Managers in selected International Higher Education Institutions and Managers at the Nelson Mandela Metropolitan University (NMMU). The online questionnaires were developed to elicit information to include in the proposed framework. To analyse results, both descriptive and inferential statistics such as Analysis of Variance (ANOVA) were used. Results from the surveys revealed that Higher Education Institutions globally and in South Africa are grappling with the same issues. When it comes to Sustainability Reporting, factors such as information culture and Business Intelligence maturity levels were not found to be very different among the various institutions. In the case study at NMMU, correlational analysis confirmed that variables such as Management buying and the availability of BI reports were positively related to effective strategic planning and vice versa. Similarly, a strong correlation was observed between reporting guidelines and strategic planning. Moreover, the study highlighted the critical role of management and leadership in a university in creating an environment that supports Sustainability Reporting. In conclusion, it was recommended that efforts should be directed at creating awareness and at training staff on aspects that promote sustainability. It is incumbent upon the institution to take advantage of and promote technological tools and techniques to enable the easy flow of data and information in understandable and usable formats to all its stakeholders. Finally, a Framework for Sustainability Reporting for Higher Education Institutions (FSRHEI) and guidelines for implementing Sustainability Reports are proposed.
- Full Text:
- Date Issued: 2014
A systematic review of the effectiveness of animal-assisted interventions
- Authors: Badenhorst, Estelle
- Date: 2014
- Subjects: Animals -- Therapeutic use , Human-animal relationships
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9980 , http://hdl.handle.net/10948/d1021139
- Description: There is a global increase in research on the benefits of animals and the value of incorporating them into interventional practices. This is referred to as animal-assisted interventions. Due to the novelty of this type of intervention and the accompanying complexity of variables, a need exists to explore the various aspects within these interventions. Looking specifically at animal-assisted interventions within the mental health field, this study focuses on the psycho-therapeutic value of companion animals, such as dogs and cats. The primary aim of this study was to identify the mechanisms through which an animal-assisted intervention exerts its influence. A secondary aim was to indentify salient methodological aspects within the included studies. A systematic review of existing literature was undertaken to explore these factors. Each study was appraised against specific inclusion and exclusion criteria and themes were extracted. The data was synthesised, integrated and discussed in relation to previously conducted studies in relevant fields. Six themes emerged from the systematic review. These included enhanced comfort, the living nature of animals, physical contact, adjunctive nature, an affinity for animals, as well as methodological considerations. Based on these emergent themes conclusions were drawn as to the psycho-therapeutic influences of companion animals. This may serve as informative knowledge regarding animal-assisted interventions for practitioners seeking additional methods to reach treatment goals. Information is also provided for researchers interested in the field, particularly methodological considerations, before embarking on a study of animal-assisted intervention efficacy.
- Full Text:
- Date Issued: 2014
- Authors: Badenhorst, Estelle
- Date: 2014
- Subjects: Animals -- Therapeutic use , Human-animal relationships
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9980 , http://hdl.handle.net/10948/d1021139
- Description: There is a global increase in research on the benefits of animals and the value of incorporating them into interventional practices. This is referred to as animal-assisted interventions. Due to the novelty of this type of intervention and the accompanying complexity of variables, a need exists to explore the various aspects within these interventions. Looking specifically at animal-assisted interventions within the mental health field, this study focuses on the psycho-therapeutic value of companion animals, such as dogs and cats. The primary aim of this study was to identify the mechanisms through which an animal-assisted intervention exerts its influence. A secondary aim was to indentify salient methodological aspects within the included studies. A systematic review of existing literature was undertaken to explore these factors. Each study was appraised against specific inclusion and exclusion criteria and themes were extracted. The data was synthesised, integrated and discussed in relation to previously conducted studies in relevant fields. Six themes emerged from the systematic review. These included enhanced comfort, the living nature of animals, physical contact, adjunctive nature, an affinity for animals, as well as methodological considerations. Based on these emergent themes conclusions were drawn as to the psycho-therapeutic influences of companion animals. This may serve as informative knowledge regarding animal-assisted interventions for practitioners seeking additional methods to reach treatment goals. Information is also provided for researchers interested in the field, particularly methodological considerations, before embarking on a study of animal-assisted intervention efficacy.
- Full Text:
- Date Issued: 2014
A teaching case study on the effect of growth on organisational leadership and culture at hardware warehouse as the organisation grew from one store to 18 stores
- Authors: Mfabane, Masiwakhe
- Date: 2014
- Subjects: Corporate culture -- South Africa -- Case studies , Leadership -- South Africa -- Case studies , Management -- South Africa -- Case studies , Hardware stores -- South Africa -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:829 , http://hdl.handle.net/10962/d1013008
- Description: From summary:The main objective of this research study was to write up a teaching case study, based on Greiner’s (1998) model of organisational development, outlining what effect the growth of Hardware Warehouse had on the leadership and culture of the organisation. The study is a teaching case study in the form of “a descriptive case focusing on presenting a description of past events and decisions” (Cappel and Schwager, 2002: 289).
- Full Text:
- Date Issued: 2014
- Authors: Mfabane, Masiwakhe
- Date: 2014
- Subjects: Corporate culture -- South Africa -- Case studies , Leadership -- South Africa -- Case studies , Management -- South Africa -- Case studies , Hardware stores -- South Africa -- Management
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:829 , http://hdl.handle.net/10962/d1013008
- Description: From summary:The main objective of this research study was to write up a teaching case study, based on Greiner’s (1998) model of organisational development, outlining what effect the growth of Hardware Warehouse had on the leadership and culture of the organisation. The study is a teaching case study in the form of “a descriptive case focusing on presenting a description of past events and decisions” (Cappel and Schwager, 2002: 289).
- Full Text:
- Date Issued: 2014
A temporal dimension to the influence of pollen rewards on bee behaviour and fecundity in Aloe tenuior
- Duffy, Karl J, Johnson, Steven D, Peter, Craig I
- Authors: Duffy, Karl J , Johnson, Steven D , Peter, Craig I
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:6561 , http://hdl.handle.net/10962/d1011735 , http://dx.doi.org/10.1371/journal.pone.0094908
- Description: The net effect of pollen production on fecundity in plants can range from negative – when self-pollen interferes with fecundity due to incompatibility mechanisms, to positive – when pollen availability is associated with increased pollinator visitation and fecundity due to its utilization as a reward. We investigated the responses of bees to pollen and nectar rewards, and the effects of these rewards on pollen deposition and fecundity in the hermaphroditic succulent shrub Aloe tenuior. Self-pollinated plants failed to set fruit, but their ovules were regularly penetrated by self-pollen tubes, which uniformly failed to develop into seeds as expected from ovarian self-incompatibility (or strong early inbreeding depression). Bees consistently foraged for pollen during the morning and early afternoon, but switched to nectar in the late afternoon. As a consequence of this differential foraging, we were able to test the relative contribution to fecundity of pollen- versus nectar-collecting flower visitors. We exposed emasculated and intact flowers in either the morning or late afternoon to foraging bees and showed that emasculation reduced pollen deposition by insects in the morning, but had little effect in the afternoon. Despite the potential for self-pollination to result in ovule discounting due to late-acting self-sterility, fecundity was severely reduced in artificially emasculated plants. Although there were temporal fluctuations in reward preference, most bee visits were for pollen rewards. Therefore the benefit of providing pollen that is accessible to bee foragers outweighs any potential costs to fitness in terms of gender interference in this species.
- Full Text:
- Date Issued: 2014
- Authors: Duffy, Karl J , Johnson, Steven D , Peter, Craig I
- Date: 2014
- Language: English
- Type: Article
- Identifier: vital:6561 , http://hdl.handle.net/10962/d1011735 , http://dx.doi.org/10.1371/journal.pone.0094908
- Description: The net effect of pollen production on fecundity in plants can range from negative – when self-pollen interferes with fecundity due to incompatibility mechanisms, to positive – when pollen availability is associated with increased pollinator visitation and fecundity due to its utilization as a reward. We investigated the responses of bees to pollen and nectar rewards, and the effects of these rewards on pollen deposition and fecundity in the hermaphroditic succulent shrub Aloe tenuior. Self-pollinated plants failed to set fruit, but their ovules were regularly penetrated by self-pollen tubes, which uniformly failed to develop into seeds as expected from ovarian self-incompatibility (or strong early inbreeding depression). Bees consistently foraged for pollen during the morning and early afternoon, but switched to nectar in the late afternoon. As a consequence of this differential foraging, we were able to test the relative contribution to fecundity of pollen- versus nectar-collecting flower visitors. We exposed emasculated and intact flowers in either the morning or late afternoon to foraging bees and showed that emasculation reduced pollen deposition by insects in the morning, but had little effect in the afternoon. Despite the potential for self-pollination to result in ovule discounting due to late-acting self-sterility, fecundity was severely reduced in artificially emasculated plants. Although there were temporal fluctuations in reward preference, most bee visits were for pollen rewards. Therefore the benefit of providing pollen that is accessible to bee foragers outweighs any potential costs to fitness in terms of gender interference in this species.
- Full Text:
- Date Issued: 2014
A virtual-community-centric model for coordination in the South African public sector
- Thomas, Godwin Dogara Ayenajeh
- Authors: Thomas, Godwin Dogara Ayenajeh
- Date: 2014
- Subjects: Electronic data processing -- Distributed processing , Interprofessional relations , Virtual work teams
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9831 , http://hdl.handle.net/10948/d1021073
- Description: Organizations face challenges constantly owing to limited resources. As such, to take advantage of new opportunities and to mitigate possible risks they look for new ways to collaborate, by sharing knowledge and competencies. Coordination among partners is critical in order to achieve success. The segmented South African public sector is no different. Driven by the desire to ensure proper service delivery in this sector, various government bodies and service providers play different roles towards the attainment of common goals. This is easier said than done, given the complexity of the distributed nature of the environment. Heterogeneity, autonomy, and the increasing need to collaborate provoke the need to develop an integrative and dynamic coordination support service system in the SA public sector. Thus, the research looks to theories/concepts and existing coordination practices to ground the process of development. To inform the design of the proposed artefact the research employs an interdisciplinary approach championed by coordination theory to review coordination-related theories and concepts. The effort accounts for coordination constructs that characterize and transform the problem and solution spaces. Thus, requirements are explicit towards identifying coordination breakdowns and their resolution. Furthermore, how coordination in a distributed environment is supported in practice is considered from a socio-technical perspective in an effort to account holistically for coordination support. Examining existing solutions identified shortcomings that, if addressed, can help to improve the solutions for coordination, which are often rigidly and narrowly defined. The research argues that introducing a mediating technological artefact conceived from a virtual community and service lenses can serve as a solution to the problem. By adopting a design-science research paradigm, the research develops a model as a primary artefact to support coordination from a collaboration standpoint. The suggestions from theory and practice and the unique case requirement identified through a novel case analysis framework form the basis of the model design. The proposed model support operation calls for an architecture which employs a design pattern that divides a complex whole into smaller, simpler parts, with the aim of reducing the system complexity. Four fundamental functions of the supporting architecture are introduced and discussed as they would support the operation and activities of the proposed collaboration lifecycle model geared towards streamlining coordination in a distributed environment. As part of the model development knowledge contributions are made in several ways. Firstly, an analytical instrument is presented that can be used by an enterprise architect or business analyst to study the coordination status quo of a collaborative activity in a distributed environment. Secondly, a lifecycle model is presented as meta-process model with activities that are geared towards streamlining the coordination of dynamic collaborative activities or projects. Thirdly, an architecture that will enable the technical virtual community-centric, context-aware environment that hosts the process-based operations is offered. Finally, the validation tool that represents the applied contribution to the research that promises possible adaptation for similar circumstances is presented. The artefacts contribute towards a design theory in IS research for the development and improvement of coordination support services in a distributed environment such as the South African public sector.
- Full Text:
- Date Issued: 2014
- Authors: Thomas, Godwin Dogara Ayenajeh
- Date: 2014
- Subjects: Electronic data processing -- Distributed processing , Interprofessional relations , Virtual work teams
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9831 , http://hdl.handle.net/10948/d1021073
- Description: Organizations face challenges constantly owing to limited resources. As such, to take advantage of new opportunities and to mitigate possible risks they look for new ways to collaborate, by sharing knowledge and competencies. Coordination among partners is critical in order to achieve success. The segmented South African public sector is no different. Driven by the desire to ensure proper service delivery in this sector, various government bodies and service providers play different roles towards the attainment of common goals. This is easier said than done, given the complexity of the distributed nature of the environment. Heterogeneity, autonomy, and the increasing need to collaborate provoke the need to develop an integrative and dynamic coordination support service system in the SA public sector. Thus, the research looks to theories/concepts and existing coordination practices to ground the process of development. To inform the design of the proposed artefact the research employs an interdisciplinary approach championed by coordination theory to review coordination-related theories and concepts. The effort accounts for coordination constructs that characterize and transform the problem and solution spaces. Thus, requirements are explicit towards identifying coordination breakdowns and their resolution. Furthermore, how coordination in a distributed environment is supported in practice is considered from a socio-technical perspective in an effort to account holistically for coordination support. Examining existing solutions identified shortcomings that, if addressed, can help to improve the solutions for coordination, which are often rigidly and narrowly defined. The research argues that introducing a mediating technological artefact conceived from a virtual community and service lenses can serve as a solution to the problem. By adopting a design-science research paradigm, the research develops a model as a primary artefact to support coordination from a collaboration standpoint. The suggestions from theory and practice and the unique case requirement identified through a novel case analysis framework form the basis of the model design. The proposed model support operation calls for an architecture which employs a design pattern that divides a complex whole into smaller, simpler parts, with the aim of reducing the system complexity. Four fundamental functions of the supporting architecture are introduced and discussed as they would support the operation and activities of the proposed collaboration lifecycle model geared towards streamlining coordination in a distributed environment. As part of the model development knowledge contributions are made in several ways. Firstly, an analytical instrument is presented that can be used by an enterprise architect or business analyst to study the coordination status quo of a collaborative activity in a distributed environment. Secondly, a lifecycle model is presented as meta-process model with activities that are geared towards streamlining the coordination of dynamic collaborative activities or projects. Thirdly, an architecture that will enable the technical virtual community-centric, context-aware environment that hosts the process-based operations is offered. Finally, the validation tool that represents the applied contribution to the research that promises possible adaptation for similar circumstances is presented. The artefacts contribute towards a design theory in IS research for the development and improvement of coordination support services in a distributed environment such as the South African public sector.
- Full Text:
- Date Issued: 2014
Academic development as enhancement: celebrating a decade of the TLC through the annual teaching week
- Jonas, N, Schekle, L, Toni, N
- Authors: Jonas, N , Schekle, L , Toni, N
- Date: 2014
- Language: English
- Type: Newsletter
- Identifier: vital:12226 , http://hdl.handle.net/10353/d1016144
- Description: Teaching and Learning Centre newsletter 2014 first edition
- Full Text: false
- Date Issued: 2014
- Authors: Jonas, N , Schekle, L , Toni, N
- Date: 2014
- Language: English
- Type: Newsletter
- Identifier: vital:12226 , http://hdl.handle.net/10353/d1016144
- Description: Teaching and Learning Centre newsletter 2014 first edition
- Full Text: false
- Date Issued: 2014
Accounting student's success factors: an exploratory investigation
- Authors: Stack, Elizabeth M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/2134 , vital:20258
- Description: This presentation is aimed at identifying possible success factors leading to the success of students studying accounting, as well as to hightlight some of the problems they may face.
- Full Text:
- Date Issued: 2014
- Authors: Stack, Elizabeth M
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/2134 , vital:20258
- Description: This presentation is aimed at identifying possible success factors leading to the success of students studying accounting, as well as to hightlight some of the problems they may face.
- Full Text:
- Date Issued: 2014
Activated carbon from lignocellulosic waste residues: effect of activating agent on porosity characteristics and use as adsorbents for organic species
- Olorundare, O F, Okonkwo, J O, Msagati, T A M, Mamba, Bhekie B, Krause, Rui W M
- Authors: Olorundare, O F , Okonkwo, J O , Msagati, T A M , Mamba, Bhekie B , Krause, Rui W M
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125233 , vital:35748 , https://doi.org/10.1007/s11270-014-1876-2
- Description: This paper reports on the effect of activating agents such as the impregnation ratio of phosphoric acid (1:1–1:5) at constant activation temperature on the performance of porous activated carbon from waste residues (maize tassel). The variation in the impregnation ratio of the produced activated carbon (AC) from 1:1 to 1:5 enabled the preparation of a high surface area (1,263 m2/g) and a large pore volume (1.592 cm3/g) of AC produced from maize tassel (MT) using a convectional chemical activating agent (phosphoric acid). Impregnation ratios (IR) of the precursors were varied between 1:1 and 1:5 in which it was found that the ratio of 1:4 was optimal based on the high surface area, while 1:5 has the optimal pore volume value for the produced activated carbon.
- Full Text:
- Date Issued: 2014
- Authors: Olorundare, O F , Okonkwo, J O , Msagati, T A M , Mamba, Bhekie B , Krause, Rui W M
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125233 , vital:35748 , https://doi.org/10.1007/s11270-014-1876-2
- Description: This paper reports on the effect of activating agents such as the impregnation ratio of phosphoric acid (1:1–1:5) at constant activation temperature on the performance of porous activated carbon from waste residues (maize tassel). The variation in the impregnation ratio of the produced activated carbon (AC) from 1:1 to 1:5 enabled the preparation of a high surface area (1,263 m2/g) and a large pore volume (1.592 cm3/g) of AC produced from maize tassel (MT) using a convectional chemical activating agent (phosphoric acid). Impregnation ratios (IR) of the precursors were varied between 1:1 and 1:5 in which it was found that the ratio of 1:4 was optimal based on the high surface area, while 1:5 has the optimal pore volume value for the produced activated carbon.
- Full Text:
- Date Issued: 2014
Adherence to antiretroviral therapy in children in Zimbabwe: a randomized control trial to validate a new self-reported adherence monitoring tool
- Authors: Mugore, Linnetie
- Date: 2014
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54734 , vital:26607
- Description: Background: Among children taking antiretroviral therapy (ART), self-reports have been widely reported to over-estimate adherence levels. Pill count adherence levels are often lower than self-reported levels, with unannounced home pill count adherence being lower than facility based pill count adherence. There is often poor agreement between pill count adherence levels and those measured using other objective adherence measuring methods such as Medication Event Monitoring Systems (MEMS®), which is widely viewed as the gold standard for adherence measurement. Objectives: The aim of this study was to design and evaluate a new self-reported paediatric adherence monitoring tool, assess the feasibility of using pill count methods in monitoring adherence and identify challenges to reporting adherence among children on ART in rural and urban Zimbabwe. Methods A dual centre, superiority, parallel design RCT was conducted to evaluate the newly-developed visually- and verbally-cued „past 10 days‟ tool for the assessment of adherence in children on ART at two sites in Zimbabwe; Harare Central Children‟s Hospital in an urban setting, and Murambinda Mission Hospital, a rural site. Child-caregiver pairs presenting to one of these facilities for the child‟s review of ART and refill of the medication were recruited, signed informed consent obtained, and were randomised for self-reported adherence monitoring into either the experimental group („new 10-day tool‟) or the control group („PACTG-style‟ self-report tool). Data (demographic, socioeconomic, and reported adherence) were collected in individual interviews with child-caregiver pairs. Additional adherence monitoring methods used for both groups included the Morisky-8-Item Medication Adherence Scale (MMAS-8) and a facility based pill count. FGDs were held with groups of caregivers and groups of children ≥13 years of age to understand reasons for non-adherence as well as issues around reporting non-adherence. Superiority testing was conducted by comparing adherent proportions and their confidence intervals (95% CI). Further concurrent validity test was done using the Mann-Whitney U test to evaluate the relationship between the new tool and the MMAS-8 scores. Agreement between the child and caregiver reports of adherence was used as a test of reliability of the new tool using the kappa statistic. Socio-demographic, clinical and care-related factors associated with adherence were identified using reported adherence in both child and caregiver groups in a logistic regression model. Two pill count methods were assessed for feasibility using the proportions of children with complete data for calculating adherence levels, and their CI and a comparison of the two methods, a routinely-used method and one that incorporated the reported residual quantity (RRQ) of medication at last refill. Results : Analysis included 245 child-caregiver pairs, 123 in the experimental group and 122 in the control group. The median age for children was 9 years. In the experimental group, adherence by caregiver and child reports ranged from 94.3% - 98.4% and 78.4% - 96.1%, and those in the control group ranged from 89.2% - 97.5% and 71.2% - 98.1%, respectively. There was no significant difference between adherence levels in the two groups. Adherence levels measured by both the experimental and control tools were found to be associated with MMAS-8 adherence levels (p <0.05). Agreement between child- and caregiver-reported adherence was moderate though significant (kappa; 0.407, p <0.05). Only about half of the children had adequate data to compute pill counts. Proportions adherent at 95% cut-off were 39% by the „routine pill count‟ and 58% by the „Pill count RRQ‟. Being an orphan was associated with child reported-adherence whereas use of non-human reminders, having a maternal relative as a primary caregiver and knowledge of dose frequency, were all associated with caregiver-reported adherence. Major causes of non-adherence mentioned during the FGDs included interference of medication administration times with scheduling of routine socio-economic activities and lack of support from some non-biological caregivers. Reporting of non-adherence appeared to be hampered by perceptions of negative reactions by healthcare workers to these reports and by caregivers being unaware that the child missed some doses. Conclusions: The „new 10-day tool‟ was not shown to be superior to the „PACTG-style tool‟ in detecting non-adherence, however this new tool was found to be a valid and reliable adherence monitoring tool that included a moderately long recall period of 10 days, can be applied without the need for the respondent to remember names of individual medicines in the
- Full Text:
- Date Issued: 2014
- Authors: Mugore, Linnetie
- Date: 2014
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54734 , vital:26607
- Description: Background: Among children taking antiretroviral therapy (ART), self-reports have been widely reported to over-estimate adherence levels. Pill count adherence levels are often lower than self-reported levels, with unannounced home pill count adherence being lower than facility based pill count adherence. There is often poor agreement between pill count adherence levels and those measured using other objective adherence measuring methods such as Medication Event Monitoring Systems (MEMS®), which is widely viewed as the gold standard for adherence measurement. Objectives: The aim of this study was to design and evaluate a new self-reported paediatric adherence monitoring tool, assess the feasibility of using pill count methods in monitoring adherence and identify challenges to reporting adherence among children on ART in rural and urban Zimbabwe. Methods A dual centre, superiority, parallel design RCT was conducted to evaluate the newly-developed visually- and verbally-cued „past 10 days‟ tool for the assessment of adherence in children on ART at two sites in Zimbabwe; Harare Central Children‟s Hospital in an urban setting, and Murambinda Mission Hospital, a rural site. Child-caregiver pairs presenting to one of these facilities for the child‟s review of ART and refill of the medication were recruited, signed informed consent obtained, and were randomised for self-reported adherence monitoring into either the experimental group („new 10-day tool‟) or the control group („PACTG-style‟ self-report tool). Data (demographic, socioeconomic, and reported adherence) were collected in individual interviews with child-caregiver pairs. Additional adherence monitoring methods used for both groups included the Morisky-8-Item Medication Adherence Scale (MMAS-8) and a facility based pill count. FGDs were held with groups of caregivers and groups of children ≥13 years of age to understand reasons for non-adherence as well as issues around reporting non-adherence. Superiority testing was conducted by comparing adherent proportions and their confidence intervals (95% CI). Further concurrent validity test was done using the Mann-Whitney U test to evaluate the relationship between the new tool and the MMAS-8 scores. Agreement between the child and caregiver reports of adherence was used as a test of reliability of the new tool using the kappa statistic. Socio-demographic, clinical and care-related factors associated with adherence were identified using reported adherence in both child and caregiver groups in a logistic regression model. Two pill count methods were assessed for feasibility using the proportions of children with complete data for calculating adherence levels, and their CI and a comparison of the two methods, a routinely-used method and one that incorporated the reported residual quantity (RRQ) of medication at last refill. Results : Analysis included 245 child-caregiver pairs, 123 in the experimental group and 122 in the control group. The median age for children was 9 years. In the experimental group, adherence by caregiver and child reports ranged from 94.3% - 98.4% and 78.4% - 96.1%, and those in the control group ranged from 89.2% - 97.5% and 71.2% - 98.1%, respectively. There was no significant difference between adherence levels in the two groups. Adherence levels measured by both the experimental and control tools were found to be associated with MMAS-8 adherence levels (p <0.05). Agreement between child- and caregiver-reported adherence was moderate though significant (kappa; 0.407, p <0.05). Only about half of the children had adequate data to compute pill counts. Proportions adherent at 95% cut-off were 39% by the „routine pill count‟ and 58% by the „Pill count RRQ‟. Being an orphan was associated with child reported-adherence whereas use of non-human reminders, having a maternal relative as a primary caregiver and knowledge of dose frequency, were all associated with caregiver-reported adherence. Major causes of non-adherence mentioned during the FGDs included interference of medication administration times with scheduling of routine socio-economic activities and lack of support from some non-biological caregivers. Reporting of non-adherence appeared to be hampered by perceptions of negative reactions by healthcare workers to these reports and by caregivers being unaware that the child missed some doses. Conclusions: The „new 10-day tool‟ was not shown to be superior to the „PACTG-style tool‟ in detecting non-adherence, however this new tool was found to be a valid and reliable adherence monitoring tool that included a moderately long recall period of 10 days, can be applied without the need for the respondent to remember names of individual medicines in the
- Full Text:
- Date Issued: 2014
Adolescent pregnancy: a community engaged participatory approach to design and implement an educational intervention
- Authors: Siruma, Amanda Tatenda
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/54656 , vital:26597
- Description: Millennium Development Goal (MDG) 5 focuses on improving maternal health, due to global acknowledgment that no woman should have to die as a result of complications during pregnancy and childbirth. Adolescents have an increased risk of maternal death compared with older women. Adolescent pregnancy also poses a threat to the empowerment of young girls by mitigating their physical, educational, social, and economic development. In this context, maternal health promotion strategies which inclusively target adolescents are crucial, not only in improving maternal health outcomes, but also in optimising the overall transition of adolescent girls to adulthood. This study was a first time collaborative partnership of the Faculty of Pharmacy and Community Engagement Office of Rhodes University with the Angus Gillis Foundation (a non-profit community development organisation), and community participants of Glenmore and Ndwayana, two rural communities in the Eastern Cape. The aim of this study was to identify the maternal health issue of most concern to community participants and to design and implement an appropriate educational intervention for a suitable target group. During the baseline phase of this study, ten focus group discussions (FGDs) were conducted with 76 community stakeholders. Semi-structured interviews (SSIs) were conducted with two Sisters-in-Charge from each Primary Health Care (PHC) facility in the study setting. Data on the stock status of World Health Organization (WHO) identified lifesaving priority medicines for women’s health was also collected at both PHCs. Thereafter, pre- and posteducational interventions SSIs with female adolescent participants were conducted. The educational intervention was followed up with the development of a booklet on reproductive health. FGD participants identified adolescent pregnancy as the maternal health issue of most concern. They also highlighted challenges in service delivery of ambulance services for expectant mothers in urgent need of transportation to a referral hospital. A majority of preintervention SSI participants indicated coercion from both younger and older men as a factor influencing early sexual debut amongst adolescent girls in their communities. Despite availability in the PHCs, challenges in accessing contraceptives were highlighted by the participants. Additionally, a number of sexually active adolescent girls defaulted on their next allocated visit to the PHC due to myths regarding use of oral and injectable contraceptives. During the educational intervention sessions, participants recognised knowledge gaps regarding reproductive health issues and the influence of peer pressure as constraining factors in preventing adolescent pregnancy. During the post-intervention phase, participants highlighted that the educational intervention of this study had provided a forum to discuss ways of preventing adolescent pregnancy. The educational booklet developed is intended to serve as a resource tool of the educational programme on prevention of adolescent pregnancy, which is expected to be incorporated into the Angus Gillis Foundation’s existing ‘Positive Health’ Programme. The results of this study show that community-based participatory research facilitated the identification of the maternal health issue of most concern to these communities. Working synergistically with key stakeholders in designing and implementing an educational intervention for preventing adolescent pregnancy provides a good foundation for future up scaling and sustainability of this educational programme.
- Full Text:
- Date Issued: 2014
- Authors: Siruma, Amanda Tatenda
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/54656 , vital:26597
- Description: Millennium Development Goal (MDG) 5 focuses on improving maternal health, due to global acknowledgment that no woman should have to die as a result of complications during pregnancy and childbirth. Adolescents have an increased risk of maternal death compared with older women. Adolescent pregnancy also poses a threat to the empowerment of young girls by mitigating their physical, educational, social, and economic development. In this context, maternal health promotion strategies which inclusively target adolescents are crucial, not only in improving maternal health outcomes, but also in optimising the overall transition of adolescent girls to adulthood. This study was a first time collaborative partnership of the Faculty of Pharmacy and Community Engagement Office of Rhodes University with the Angus Gillis Foundation (a non-profit community development organisation), and community participants of Glenmore and Ndwayana, two rural communities in the Eastern Cape. The aim of this study was to identify the maternal health issue of most concern to community participants and to design and implement an appropriate educational intervention for a suitable target group. During the baseline phase of this study, ten focus group discussions (FGDs) were conducted with 76 community stakeholders. Semi-structured interviews (SSIs) were conducted with two Sisters-in-Charge from each Primary Health Care (PHC) facility in the study setting. Data on the stock status of World Health Organization (WHO) identified lifesaving priority medicines for women’s health was also collected at both PHCs. Thereafter, pre- and posteducational interventions SSIs with female adolescent participants were conducted. The educational intervention was followed up with the development of a booklet on reproductive health. FGD participants identified adolescent pregnancy as the maternal health issue of most concern. They also highlighted challenges in service delivery of ambulance services for expectant mothers in urgent need of transportation to a referral hospital. A majority of preintervention SSI participants indicated coercion from both younger and older men as a factor influencing early sexual debut amongst adolescent girls in their communities. Despite availability in the PHCs, challenges in accessing contraceptives were highlighted by the participants. Additionally, a number of sexually active adolescent girls defaulted on their next allocated visit to the PHC due to myths regarding use of oral and injectable contraceptives. During the educational intervention sessions, participants recognised knowledge gaps regarding reproductive health issues and the influence of peer pressure as constraining factors in preventing adolescent pregnancy. During the post-intervention phase, participants highlighted that the educational intervention of this study had provided a forum to discuss ways of preventing adolescent pregnancy. The educational booklet developed is intended to serve as a resource tool of the educational programme on prevention of adolescent pregnancy, which is expected to be incorporated into the Angus Gillis Foundation’s existing ‘Positive Health’ Programme. The results of this study show that community-based participatory research facilitated the identification of the maternal health issue of most concern to these communities. Working synergistically with key stakeholders in designing and implementing an educational intervention for preventing adolescent pregnancy provides a good foundation for future up scaling and sustainability of this educational programme.
- Full Text:
- Date Issued: 2014
Adolescent pregnancy: A feminist issue
- Authors: Macleod, Catriona I
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434360 , vital:73051 , ISBN 978-1-4899-8025-0 , https://link.springer.com/chapter/10.1007/978-1-4899-8026-7_6
- Description: Pregnancy and mothering are enduring and central concerns of feminism. DiQuinzo (1999) sums this up in stating that “mothering is both an important site at which the central concepts of feminist theory are elaborated and a site at which these concepts are challenged and reworked.” Stephens (2004) argues, ‘…reproduction and mothering are central to theories of patriarchy and women’s unequal position in Western society…Childbirth can paradoxically be seen as both a cause of women’s subordinate position in society and a means of empowerment.’ Yet, despite the pivotal nature of pregnancy and mothering in feminist literature, there has been surprisingly little direct engagement by feminists in the area of ‘adolescent pregnancy.’ The engagement that there has been is a whisper in relation to the plethora of public health, medical, and psychological writings on ‘adolescent pregnancy.’ The feminists who have engaged with ‘adolescent pregnancy’ have, from their initial engagement and to varying degrees, tried to undermine simple interpretations of ‘adolescent pregnancy’ as a social problem and to link micro- and macro-level gender relations to occurrence of, and responses to, ‘adolescent pregnancy.’ Thus, for example, in the 1980s, Chilman (1985) asserted, ‘Sexism particularly afflicts programs and policies for these young people [unmarried teenage parents] as well as the behaviors that lead up to their becoming unmarried parents.’ In the 1990s, Pillow (1997), using a combination of feminist and postmodern theory, argued that ‘teen research and policy interventions can be understood as entrenched in the dilemmas of modernism, resulting often in normative assumptions that reflect our paradoxical attitudes and practices concerning female sexuality.’ More recently, Wilson and Huntington (2005) observed ‘adolescent pregnancy’ at a time when rates of fertility among young women are decreasing in ‘Western’ societies is ‘underpinned by changing social and political imperatives regarding the role of women in these countries.’
- Full Text:
- Date Issued: 2014
- Authors: Macleod, Catriona I
- Date: 2014
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434360 , vital:73051 , ISBN 978-1-4899-8025-0 , https://link.springer.com/chapter/10.1007/978-1-4899-8026-7_6
- Description: Pregnancy and mothering are enduring and central concerns of feminism. DiQuinzo (1999) sums this up in stating that “mothering is both an important site at which the central concepts of feminist theory are elaborated and a site at which these concepts are challenged and reworked.” Stephens (2004) argues, ‘…reproduction and mothering are central to theories of patriarchy and women’s unequal position in Western society…Childbirth can paradoxically be seen as both a cause of women’s subordinate position in society and a means of empowerment.’ Yet, despite the pivotal nature of pregnancy and mothering in feminist literature, there has been surprisingly little direct engagement by feminists in the area of ‘adolescent pregnancy.’ The engagement that there has been is a whisper in relation to the plethora of public health, medical, and psychological writings on ‘adolescent pregnancy.’ The feminists who have engaged with ‘adolescent pregnancy’ have, from their initial engagement and to varying degrees, tried to undermine simple interpretations of ‘adolescent pregnancy’ as a social problem and to link micro- and macro-level gender relations to occurrence of, and responses to, ‘adolescent pregnancy.’ Thus, for example, in the 1980s, Chilman (1985) asserted, ‘Sexism particularly afflicts programs and policies for these young people [unmarried teenage parents] as well as the behaviors that lead up to their becoming unmarried parents.’ In the 1990s, Pillow (1997), using a combination of feminist and postmodern theory, argued that ‘teen research and policy interventions can be understood as entrenched in the dilemmas of modernism, resulting often in normative assumptions that reflect our paradoxical attitudes and practices concerning female sexuality.’ More recently, Wilson and Huntington (2005) observed ‘adolescent pregnancy’ at a time when rates of fertility among young women are decreasing in ‘Western’ societies is ‘underpinned by changing social and political imperatives regarding the role of women in these countries.’
- Full Text:
- Date Issued: 2014
Age, growth, reproduction and sexual dimorphism of the striped dolphin, Stenella coeruleoalba, off the south-east coast of southern Africa
- Authors: Bishop, Amy Ruth
- Date: 2014
- Subjects: Striped dolphin -- Conservation -- Africa, Southern , Striped dolphin -- Development -- Africa, Southern , Striped dolphin -- Africa, Southern -- Reproduction , Striped dolphin -- Age determination -- Africa, Southern , Dolphins -- Conservation -- Africa, Southern , Dolphins -- Development -- Africa, Southern , Dolphins -- Africa, Southern -- Reproduction , Dolphins -- Age determination -- Africa, Southern , Dimorphism (Animals)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5848 , http://hdl.handle.net/10962/d1011600 , Striped dolphin -- Conservation -- Africa, Southern , Striped dolphin -- Development -- Africa, Southern , Striped dolphin -- Africa, Southern -- Reproduction , Striped dolphin -- Age determination -- Africa, Southern , Dolphins -- Conservation -- Africa, Southern , Dolphins -- Development -- Africa, Southern , Dolphins -- Africa, Southern -- Reproduction , Dolphins -- Age determination -- Africa, Southern , Dimorphism (Animals)
- Description: The striped dolphin, Stenella coeruleoalba, is an oceanic dolphin found worldwide in tropical to warm temperate waters. Globally populations are threatened through direct fishing, bycatch and pollution. Little is known about the life history of this species in South African waters and it is currently listed as ‘Data Deficient’ by the International Union for Conservation of Nature (IUCN). Critical to the conservation and management of this species is an understanding of basic life history parameters. For the present study, metadata and tissues from 101 stranded S. coeruleoalba along the south-east coast of southern Africa between 1969 and 2012 were analyzed to examine age and growth, male and female reproduction and sexual dimorphism. Age and growth were determined by counting the number of growth layer groups (GLG’s) present in their teeth. A von Bertalanffy growth curve gave the best fit to the data and indicated that physical maturity was reached around 21 years in males and 18 years in females. Additionally, asymptotic lengths were reached at 231cm and 224cm in males and females, respectively. The maximum ages obtained were 21 years for males and 20 years for females. Length at birth was estimated to be between 116cm and 119cm for males and between 112cm and 114cm for females. The reproductive status of the adult dolphins was assessed by histological and macroscopic analyses of gonadal tissue. Sexual maturity was attained before physical maturity in both sexes. The males reached sexual maturity between 8 and 12 years of age and between 209 and 224cm in total body length. The maximum combined testis weight comprised about 0.24% of the total body weight and sexual maturity was reached between a combined testis weight of 16 and 41g, a mean testis length of 8 and 10cm, and a mean seminiferous tubule diameter of 44 and 70μm. Females attained sexual maturity between 7 and 8 years of age and between 213 and 216 cm in total body length. The ovulation rate was 0.32 per year and the majority of ovulations occurred in the left ovary, with ovulations occurring in the right ovary only in individuals older than 10 years of age. The annual pregnancy rate was calculated to be 26%. Reproductive seasonality could not be established due to the small sample size and the absence of samples throughout the year. However, both conceptions and births appear to occur in both August and December/January. Additionally, testis weight and seminiferous tubule diameters appear to fluctuate throughout the year, which could suggest reproductive seasonality in this species. Sexual size dimorphism in mature adults was evident for a number of external measurements, however, sexual shape dimorphism was not present in this species. Mature males had significantly longer and wider pectoral fins, dorsal fins and flukes than females (p<0.05 in all cases). It was suggested that the larger appendages are required for male on male combat during intraspecific competition for females. Additionally, larger appendages aid in thermoregulation, propulsion and maneuverability. Females had a significantly greater distance between the tip upper jaw and the genital aperture and anus, which was expected due to differences in anatomy between male and female genital openings. Overall, S. coeruleoalba did not exhibit distinct sexual dimorphism and together with the relatively small testes in relation to the total body weight (0.24%) it was proposed that this species demonstrates a less extreme form of polygyny. Additionaly, the results of this study are important to the understanding of the basic biology of the species.
- Full Text:
- Date Issued: 2014
- Authors: Bishop, Amy Ruth
- Date: 2014
- Subjects: Striped dolphin -- Conservation -- Africa, Southern , Striped dolphin -- Development -- Africa, Southern , Striped dolphin -- Africa, Southern -- Reproduction , Striped dolphin -- Age determination -- Africa, Southern , Dolphins -- Conservation -- Africa, Southern , Dolphins -- Development -- Africa, Southern , Dolphins -- Africa, Southern -- Reproduction , Dolphins -- Age determination -- Africa, Southern , Dimorphism (Animals)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5848 , http://hdl.handle.net/10962/d1011600 , Striped dolphin -- Conservation -- Africa, Southern , Striped dolphin -- Development -- Africa, Southern , Striped dolphin -- Africa, Southern -- Reproduction , Striped dolphin -- Age determination -- Africa, Southern , Dolphins -- Conservation -- Africa, Southern , Dolphins -- Development -- Africa, Southern , Dolphins -- Africa, Southern -- Reproduction , Dolphins -- Age determination -- Africa, Southern , Dimorphism (Animals)
- Description: The striped dolphin, Stenella coeruleoalba, is an oceanic dolphin found worldwide in tropical to warm temperate waters. Globally populations are threatened through direct fishing, bycatch and pollution. Little is known about the life history of this species in South African waters and it is currently listed as ‘Data Deficient’ by the International Union for Conservation of Nature (IUCN). Critical to the conservation and management of this species is an understanding of basic life history parameters. For the present study, metadata and tissues from 101 stranded S. coeruleoalba along the south-east coast of southern Africa between 1969 and 2012 were analyzed to examine age and growth, male and female reproduction and sexual dimorphism. Age and growth were determined by counting the number of growth layer groups (GLG’s) present in their teeth. A von Bertalanffy growth curve gave the best fit to the data and indicated that physical maturity was reached around 21 years in males and 18 years in females. Additionally, asymptotic lengths were reached at 231cm and 224cm in males and females, respectively. The maximum ages obtained were 21 years for males and 20 years for females. Length at birth was estimated to be between 116cm and 119cm for males and between 112cm and 114cm for females. The reproductive status of the adult dolphins was assessed by histological and macroscopic analyses of gonadal tissue. Sexual maturity was attained before physical maturity in both sexes. The males reached sexual maturity between 8 and 12 years of age and between 209 and 224cm in total body length. The maximum combined testis weight comprised about 0.24% of the total body weight and sexual maturity was reached between a combined testis weight of 16 and 41g, a mean testis length of 8 and 10cm, and a mean seminiferous tubule diameter of 44 and 70μm. Females attained sexual maturity between 7 and 8 years of age and between 213 and 216 cm in total body length. The ovulation rate was 0.32 per year and the majority of ovulations occurred in the left ovary, with ovulations occurring in the right ovary only in individuals older than 10 years of age. The annual pregnancy rate was calculated to be 26%. Reproductive seasonality could not be established due to the small sample size and the absence of samples throughout the year. However, both conceptions and births appear to occur in both August and December/January. Additionally, testis weight and seminiferous tubule diameters appear to fluctuate throughout the year, which could suggest reproductive seasonality in this species. Sexual size dimorphism in mature adults was evident for a number of external measurements, however, sexual shape dimorphism was not present in this species. Mature males had significantly longer and wider pectoral fins, dorsal fins and flukes than females (p<0.05 in all cases). It was suggested that the larger appendages are required for male on male combat during intraspecific competition for females. Additionally, larger appendages aid in thermoregulation, propulsion and maneuverability. Females had a significantly greater distance between the tip upper jaw and the genital aperture and anus, which was expected due to differences in anatomy between male and female genital openings. Overall, S. coeruleoalba did not exhibit distinct sexual dimorphism and together with the relatively small testes in relation to the total body weight (0.24%) it was proposed that this species demonstrates a less extreme form of polygyny. Additionaly, the results of this study are important to the understanding of the basic biology of the species.
- Full Text:
- Date Issued: 2014
Aggregate stability, crust formation, steady state infiltration and mode of seedling emergence in soils with various texture and mineralogy
- Authors: Nciizah, Adornis Dakarai
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Crop Science)
- Identifier: vital:11871 , http://hdl.handle.net/10353/d1015539
- Description: The general objective of this study was to quantify the interactive effects of soil texture and mineralogy on soil crusting, infiltration and erosion and the subsequent effects on maize seedling emergence and early development using soils collected from 14 ecotopes in the Eastern Cape Province. The specific objectives were to determine; i) particulate organic matter, soil texture and mineralogy relations, ii) aggregate stability and breakdown mechanisms as affected by soil texture and organic matter, iii) crust formation and steady state infiltration, iv) rainfall pattern effects on crusting, infiltration and erodibility and v) rainfall intensity effects on crusting and mode of seedling emergence. Particulate organic matter (POM) was fractionated into litter POM, coarse POM and fine POM. Both total soil organic matter (SOM) and the POM in each fraction were determined using the weight loss on ignition procedure. Most ecotopes were either sandy loam or sandy clay loam and primary minerals especially quartz dominated the soil mineralogy. The clay content was significantly related to the total SOM (r = 0.78), hematite (r = 0.83) and quartz (r = -0.74). Aggregate stability was determined following methods described by Le Bissonnais (1996) i.e. fast wetting (FW), slow wetting (SW) and wet stirring (WSt). Aggregate breakdown followed the order; slaking < mechanical breakdown < micro-cracking for most ecotopes except Lujiko Leeufontein and Amatola Jozini where SW and WSt resulted in the least MWD respectively. Aggregate stability was significantly correlated to POM only for FW and SW and only positive but not significant for WSt. To study crust formation, aggregate sizes <2, 2 to 3, 3 to 5 mm were exposed to 60 mm hr-1 simulated rainfall. Sieving structural crusts, ~0.2 to ~0.8 mm thick with a surface layer of loose grains overlying a thin plasmic layer, formed in all ecotopes. Crusts with strengths between 0.25 and 3.42 10-4 kg m-2 developed on the <2 mm compared to <2.23 10-4 kg m-2 in the >2 mm aggregates. The reverse occurred in Alice Jozini, which had relatively low clay content of 120 g kg-1. Two significantly different groups of the SSIR were observed. The SSIR was between 1.24 and 3.60 mm hr-1 in the group of ecotopes dominated by primary minerals and relatively lower clay content. In the second group, consisting one ecotope dominated by kaolinite and relatively higher clay content, the SSIR was 15.23 mm hr-1. Rainfall pattern i.e. rainfall applied either as an eight minute single rainstorm (SR) or four-two minute intermittent rainstorms (IR) separated by a 48 h drying period significantly (p < 0.05) affected crust strength, SSIR and erosion. The IR resulted in higher crust strength and SSIR than SR. The effect of rainfall pattern on SSIR was mostly influenced by the primary minerals namely, quartz. Three maize seeds of equal size were planted in plastic pots, pre-wetted by capillary action and then subjected to simulated rainfall at three intensities for 5 min. Rainfall intensity (30, 45 and 60 mm h-1) significantly (P < 0.05) affected crust strength and mean emergence day (MED) but not emergence percentage (EMP) and shoot length (P > 0.05). The 60 mm h-1 rainfall intensity resulted in the highest crust strength and MED.
- Full Text:
- Date Issued: 2014
- Authors: Nciizah, Adornis Dakarai
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD (Crop Science)
- Identifier: vital:11871 , http://hdl.handle.net/10353/d1015539
- Description: The general objective of this study was to quantify the interactive effects of soil texture and mineralogy on soil crusting, infiltration and erosion and the subsequent effects on maize seedling emergence and early development using soils collected from 14 ecotopes in the Eastern Cape Province. The specific objectives were to determine; i) particulate organic matter, soil texture and mineralogy relations, ii) aggregate stability and breakdown mechanisms as affected by soil texture and organic matter, iii) crust formation and steady state infiltration, iv) rainfall pattern effects on crusting, infiltration and erodibility and v) rainfall intensity effects on crusting and mode of seedling emergence. Particulate organic matter (POM) was fractionated into litter POM, coarse POM and fine POM. Both total soil organic matter (SOM) and the POM in each fraction were determined using the weight loss on ignition procedure. Most ecotopes were either sandy loam or sandy clay loam and primary minerals especially quartz dominated the soil mineralogy. The clay content was significantly related to the total SOM (r = 0.78), hematite (r = 0.83) and quartz (r = -0.74). Aggregate stability was determined following methods described by Le Bissonnais (1996) i.e. fast wetting (FW), slow wetting (SW) and wet stirring (WSt). Aggregate breakdown followed the order; slaking < mechanical breakdown < micro-cracking for most ecotopes except Lujiko Leeufontein and Amatola Jozini where SW and WSt resulted in the least MWD respectively. Aggregate stability was significantly correlated to POM only for FW and SW and only positive but not significant for WSt. To study crust formation, aggregate sizes <2, 2 to 3, 3 to 5 mm were exposed to 60 mm hr-1 simulated rainfall. Sieving structural crusts, ~0.2 to ~0.8 mm thick with a surface layer of loose grains overlying a thin plasmic layer, formed in all ecotopes. Crusts with strengths between 0.25 and 3.42 10-4 kg m-2 developed on the <2 mm compared to <2.23 10-4 kg m-2 in the >2 mm aggregates. The reverse occurred in Alice Jozini, which had relatively low clay content of 120 g kg-1. Two significantly different groups of the SSIR were observed. The SSIR was between 1.24 and 3.60 mm hr-1 in the group of ecotopes dominated by primary minerals and relatively lower clay content. In the second group, consisting one ecotope dominated by kaolinite and relatively higher clay content, the SSIR was 15.23 mm hr-1. Rainfall pattern i.e. rainfall applied either as an eight minute single rainstorm (SR) or four-two minute intermittent rainstorms (IR) separated by a 48 h drying period significantly (p < 0.05) affected crust strength, SSIR and erosion. The IR resulted in higher crust strength and SSIR than SR. The effect of rainfall pattern on SSIR was mostly influenced by the primary minerals namely, quartz. Three maize seeds of equal size were planted in plastic pots, pre-wetted by capillary action and then subjected to simulated rainfall at three intensities for 5 min. Rainfall intensity (30, 45 and 60 mm h-1) significantly (P < 0.05) affected crust strength and mean emergence day (MED) but not emergence percentage (EMP) and shoot length (P > 0.05). The 60 mm h-1 rainfall intensity resulted in the highest crust strength and MED.
- Full Text:
- Date Issued: 2014