A stunting profile of children under the age of five visiting Bhisho hospital clinic, part of the umbrella project: a profile of stunting in children under the age of five in food insecure villages in Mqanduli, Ngqushwa and Bhisho hospital, Eastern Cape, South Africa
- Authors: Beyleveld, Janine
- Date: 2020
- Subjects: Children -- growth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/50201 , vital:42066
- Description: Introduction and Background: Stunting is the most prevalent form of childhood malnutrition where about 149 million children under the age of five can be classified as stunted globally. South Africa has one of the highest stunting rates in the world at 27%, causing devastating effects on economic productivity as well as on an individual’s nutritional status. The presence of stunted growth in children is a strong indicator of chronic undernutrition and highlights injustices experienced within communities. Aims and Objectives: The aim of this study is to develop a stunning profile of children under the age of five, visiting BhishoHospital’s gateway clinic in the Eastern Cape, South Africa. The objectives were to determine the prevalence of stunting of the children visiting Bhisho Hospital’s clinic and to identify the drivers of stunting in the area. Methodology: A quantitative study with a descriptive, cross-sectional design was used. The study population included all children under the age of five visiting Bhisho Hospital’s clinic. Data was collected by means of an interview-administered questionnaire. Results: The prevalence of stunting in the area was 47.5%. A significant association was found between the participants' main form of sanitation and stunting category in the group of infants younger than six months (p = 0.007) and the group older than six months(p = 0.040). Discussion: The prevalence of stunting in the area was far higher than the national average of 27%, although the majority of the sample had a normal weight. The use of non-flush toilets was found to be a risk factor for childhood stunting. Recommendation: Financial and political investment in child health needs to be placed as a top priority in South Africa to reduce stunting rates.
- Full Text:
- Date Issued: 2020
- Authors: Beyleveld, Janine
- Date: 2020
- Subjects: Children -- growth
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/50201 , vital:42066
- Description: Introduction and Background: Stunting is the most prevalent form of childhood malnutrition where about 149 million children under the age of five can be classified as stunted globally. South Africa has one of the highest stunting rates in the world at 27%, causing devastating effects on economic productivity as well as on an individual’s nutritional status. The presence of stunted growth in children is a strong indicator of chronic undernutrition and highlights injustices experienced within communities. Aims and Objectives: The aim of this study is to develop a stunning profile of children under the age of five, visiting BhishoHospital’s gateway clinic in the Eastern Cape, South Africa. The objectives were to determine the prevalence of stunting of the children visiting Bhisho Hospital’s clinic and to identify the drivers of stunting in the area. Methodology: A quantitative study with a descriptive, cross-sectional design was used. The study population included all children under the age of five visiting Bhisho Hospital’s clinic. Data was collected by means of an interview-administered questionnaire. Results: The prevalence of stunting in the area was 47.5%. A significant association was found between the participants' main form of sanitation and stunting category in the group of infants younger than six months (p = 0.007) and the group older than six months(p = 0.040). Discussion: The prevalence of stunting in the area was far higher than the national average of 27%, although the majority of the sample had a normal weight. The use of non-flush toilets was found to be a risk factor for childhood stunting. Recommendation: Financial and political investment in child health needs to be placed as a top priority in South Africa to reduce stunting rates.
- Full Text:
- Date Issued: 2020
A systematic analysis of doctoral publication trends in South Africa
- van Schalkwyk, Susan, Mouton, Johann, Redlinghuys, Herman, McKenna, Sioux
- Authors: van Schalkwyk, Susan , Mouton, Johann , Redlinghuys, Herman , McKenna, Sioux
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185826 , vital:44438 , xlink:href="http://dx.doi.org/10.17159/sajs.2020/7926"
- Description: It is incumbent upon doctoral students that their work makes a substantive contribution to the field within which it is conducted. Dissemination of this work beyond the dissertation, whether whilst studying or after graduation, is necessary to ensure that the contribution does not remain largely dormant. While dissemination can take many forms, peer-reviewed journal articles are the key medium by which knowledge is shared. We aimed to establish the proportion of doctoral theses that results in journal publications by linking South African doctoral thesis metadata to journal articles authored by doctoral candidates. To effect this matching, a customised data set was created that comprised two large databases: the South African Theses Database (SATD), which documented all doctoral degrees awarded in South Africa (2005-2014), and the South African Knowledgebase (SAK), which listed all publications submitted for subsidy to the South African Department of Higher Education and Training (2005-2017). The process followed several iterations of matching and verification, including manual inspection of the data, in order to isolate only those records for which the link was established beyond doubt. Over the period under review, 47.6% of graduates, representing 22 of the 26 higher education institutions, published at least one journal article. Results further indicate increasingly higher publication rates over time. To explore whether the journal article identified was a direct product of the study, a similarity index was developed. Over 75% of records demonstrated high similarity. While the trend towards increasing publications by graduates is promising, work in this area should be ongoing. In spite of increasing trends in publications by graduates, many are not disseminating their work, suggesting that significant bodies of research are potentially not being shared with the academic community and are therefore not contributing to the relevant discipline or field. •This study provides baseline data from which a number of further investigations can be launched, such as exploring the extent to which doctoral candidates who are also academics are publishing their work; the factors that enable or constrain publication; the other avenues of dissemination used; and whether publishing or not publishing can serve as a proxy for the quality of the doctoral work.
- Full Text:
- Date Issued: 2020
- Authors: van Schalkwyk, Susan , Mouton, Johann , Redlinghuys, Herman , McKenna, Sioux
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/185826 , vital:44438 , xlink:href="http://dx.doi.org/10.17159/sajs.2020/7926"
- Description: It is incumbent upon doctoral students that their work makes a substantive contribution to the field within which it is conducted. Dissemination of this work beyond the dissertation, whether whilst studying or after graduation, is necessary to ensure that the contribution does not remain largely dormant. While dissemination can take many forms, peer-reviewed journal articles are the key medium by which knowledge is shared. We aimed to establish the proportion of doctoral theses that results in journal publications by linking South African doctoral thesis metadata to journal articles authored by doctoral candidates. To effect this matching, a customised data set was created that comprised two large databases: the South African Theses Database (SATD), which documented all doctoral degrees awarded in South Africa (2005-2014), and the South African Knowledgebase (SAK), which listed all publications submitted for subsidy to the South African Department of Higher Education and Training (2005-2017). The process followed several iterations of matching and verification, including manual inspection of the data, in order to isolate only those records for which the link was established beyond doubt. Over the period under review, 47.6% of graduates, representing 22 of the 26 higher education institutions, published at least one journal article. Results further indicate increasingly higher publication rates over time. To explore whether the journal article identified was a direct product of the study, a similarity index was developed. Over 75% of records demonstrated high similarity. While the trend towards increasing publications by graduates is promising, work in this area should be ongoing. In spite of increasing trends in publications by graduates, many are not disseminating their work, suggesting that significant bodies of research are potentially not being shared with the academic community and are therefore not contributing to the relevant discipline or field. •This study provides baseline data from which a number of further investigations can be launched, such as exploring the extent to which doctoral candidates who are also academics are publishing their work; the factors that enable or constrain publication; the other avenues of dissemination used; and whether publishing or not publishing can serve as a proxy for the quality of the doctoral work.
- Full Text:
- Date Issued: 2020
A systematic review of the efficacy of internet-based interventions for depression and anxiety disorders: the possibilities and limitations for feasibility within South Africa
- Authors: Sealy-Fisher, Kay Tibeta
- Date: 2020
- Subjects: Depression, Mental -- Treatment -- South Africa , Anxiety disorders -- Treatment -- South Africa , Internet in psychotherapy -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/144632 , vital:38364
- Description: Technological advances may alleviate the burden on South Africa’s mental healthcare system. This study is a systematic review of literature that assesses the efficacy of high quality online interventions for depression and anxiety, and that compares the reviewed studies’ characteristics to the South African context to assist in future developments of online interventions for depression and anxiety within South Africa. This was achieved through using a 2010 systematic review of Griffiths, Farrer, and Christensen as point of departure. This research had two aims: to provide an updated systematic review of the literature reporting on the efficacy of internet-based interventions for depression and anxiety disorders; and to evaluate the possibilities and limitations for the feasibility of implementing internet-based interventions for depression and anxiety disorders in the South African context. Databases accessed were PubMed, PsycINFO, and Cochrane Central Register of Controlled Trials. Included studies must: (i) report on one or more internet-based intervention, (ii) target depression or anxiety or both, (iii) report the effect size or provide enough information to calculate it, (iv) report a measure of symptoms outcome, (v) be a Randomised Controlled Trial, (vi) include a control group that received no active intervention, (vii) be published and peer-reviewed, (viii) have been published after January 2010. The search yielded 2999 potential studies of which 20 full texts were reviewed. Of these, 75% (n=15) of the studies report effect sizes above 0.20, and 25% (n=5) of the studies report effect sizes above 0.80. Themes emergent from literature and included studies distinguished effective from non-effective studies included the use of cognitive behavioural therapy, therapist input and reminders to engage with the intervention, and duration of over 6 weeks. Attrition rates did not differ between experimental and control groups. Sample characteristics between the reviewed interventions and South Africa’s population were found to be different and is discussed. Unfortunately, 37 potential studies could not be accessed and thus not included, although several attempts were made. The majority of studies had effect sizes equal to that of face-to-face therapeutic interventions. Implications of application in South Africa’s context with limited technological familiarity, insufficiency of professionally trained therapists, poor literacy, and high costs of internet data are discussed. It is concluded that with appropriate adaptation, online internet interventions for depression and anxiety would be beneficial to South Africa’s people and assist in lowering the country’s burden of mental health disorders.
- Full Text:
- Date Issued: 2020
- Authors: Sealy-Fisher, Kay Tibeta
- Date: 2020
- Subjects: Depression, Mental -- Treatment -- South Africa , Anxiety disorders -- Treatment -- South Africa , Internet in psychotherapy -- South Africa
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/144632 , vital:38364
- Description: Technological advances may alleviate the burden on South Africa’s mental healthcare system. This study is a systematic review of literature that assesses the efficacy of high quality online interventions for depression and anxiety, and that compares the reviewed studies’ characteristics to the South African context to assist in future developments of online interventions for depression and anxiety within South Africa. This was achieved through using a 2010 systematic review of Griffiths, Farrer, and Christensen as point of departure. This research had two aims: to provide an updated systematic review of the literature reporting on the efficacy of internet-based interventions for depression and anxiety disorders; and to evaluate the possibilities and limitations for the feasibility of implementing internet-based interventions for depression and anxiety disorders in the South African context. Databases accessed were PubMed, PsycINFO, and Cochrane Central Register of Controlled Trials. Included studies must: (i) report on one or more internet-based intervention, (ii) target depression or anxiety or both, (iii) report the effect size or provide enough information to calculate it, (iv) report a measure of symptoms outcome, (v) be a Randomised Controlled Trial, (vi) include a control group that received no active intervention, (vii) be published and peer-reviewed, (viii) have been published after January 2010. The search yielded 2999 potential studies of which 20 full texts were reviewed. Of these, 75% (n=15) of the studies report effect sizes above 0.20, and 25% (n=5) of the studies report effect sizes above 0.80. Themes emergent from literature and included studies distinguished effective from non-effective studies included the use of cognitive behavioural therapy, therapist input and reminders to engage with the intervention, and duration of over 6 weeks. Attrition rates did not differ between experimental and control groups. Sample characteristics between the reviewed interventions and South Africa’s population were found to be different and is discussed. Unfortunately, 37 potential studies could not be accessed and thus not included, although several attempts were made. The majority of studies had effect sizes equal to that of face-to-face therapeutic interventions. Implications of application in South Africa’s context with limited technological familiarity, insufficiency of professionally trained therapists, poor literacy, and high costs of internet data are discussed. It is concluded that with appropriate adaptation, online internet interventions for depression and anxiety would be beneficial to South Africa’s people and assist in lowering the country’s burden of mental health disorders.
- Full Text:
- Date Issued: 2020
A theory-based approach to evaluating a Continuing Teacher Professional Development Programme aimed at strengthening environment and sustainability education
- Authors: Songqwaru, Nonyameko Zintle
- Date: 2020
- Subjects: Fundisa for Change , Environmental education -- South Africa , Teachers -- Training of -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145267 , vital:38423
- Description: This study uses a theory-based approach to evaluate the Fundisa for Change training programme, a continuing teacher professional development programme aimed at strengthening environment and sustainability education. The aim of the study was to surface assumptions that underpin the design and implementation of the Fundisa for Change training programme. The Fundisa for Change Teacher Education programme is a national collaborative programme that is implemented in all the nine provinces of South Africa. The study reports on the implementation of the programme in five provinces. The study aimed to surface the Fundisa for Change training programme’s implementation theory and programme theory as these affect programme delivery. The Fundisa for Change training programme was implemented in diverse contexts by different facilitators to different participants. To determine how training programme outcomes were achieved, use was made of context-mechanism-outcome (CMO) configurations for each site where the programme was implemented. Data used to construct CMO configurations was generated through document analysis of Fundisa for Change documents, interviews with stakeholders and participants, as well as observations of programme implementation at five sites. There were three phases to data analysis: content analysis of Fundisa for Change documents, content analysis of observation transcripts and use of the CMO configuration, an analytical tool used in realist evaluation. An initial CMO configuration was constructed prior to observing implementation of the programme and a refined CMO configuration for the Fundisa for Change training programme was constructed based on similarities between the CMO configurations constructed for each of the five sites under study. The partnership model of the Fundisa for Change training programme brought diverse expertise and resources (material, cognitive, social and emotional) which were conducive to the achievement of programme outcomes. The programme’s action context (structure, culture, agency and relations) contributed to the achievement of programme outcomes by participants. Participants’ subject content knowledge, teaching practice and assessment practice was enhanced through attending the Fundisa for Change training. On-course tasks were mediated during training and this created opportunities for participants to discuss and reflect on current practice in ways that could lead to a change in practice. In evaluating professional development programmes, an elaborated definition of context in terms of structure, culture, agency and relations enables a comprehensive exploration of potential programme mechanisms that can be activated when programmes are implemented. It is also important to disaggregate resources and reasons when identifying mechanisms as this assists with differentiating between context and mechanisms. The study offers insights into the professional learning of teachers grappling with new content and pedagogical content knowledges related to environment in the context of recent curriculum changes where the South African national school curriculum has come into focus. Environmental education programmes in South Africa have implicitly used a realist approach. This study offers the first substantive professional learning evaluation that develops this approach explicitly using Theory of Change and Realist Evaluation in combination.
- Full Text:
- Date Issued: 2020
- Authors: Songqwaru, Nonyameko Zintle
- Date: 2020
- Subjects: Fundisa for Change , Environmental education -- South Africa , Teachers -- Training of -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/145267 , vital:38423
- Description: This study uses a theory-based approach to evaluate the Fundisa for Change training programme, a continuing teacher professional development programme aimed at strengthening environment and sustainability education. The aim of the study was to surface assumptions that underpin the design and implementation of the Fundisa for Change training programme. The Fundisa for Change Teacher Education programme is a national collaborative programme that is implemented in all the nine provinces of South Africa. The study reports on the implementation of the programme in five provinces. The study aimed to surface the Fundisa for Change training programme’s implementation theory and programme theory as these affect programme delivery. The Fundisa for Change training programme was implemented in diverse contexts by different facilitators to different participants. To determine how training programme outcomes were achieved, use was made of context-mechanism-outcome (CMO) configurations for each site where the programme was implemented. Data used to construct CMO configurations was generated through document analysis of Fundisa for Change documents, interviews with stakeholders and participants, as well as observations of programme implementation at five sites. There were three phases to data analysis: content analysis of Fundisa for Change documents, content analysis of observation transcripts and use of the CMO configuration, an analytical tool used in realist evaluation. An initial CMO configuration was constructed prior to observing implementation of the programme and a refined CMO configuration for the Fundisa for Change training programme was constructed based on similarities between the CMO configurations constructed for each of the five sites under study. The partnership model of the Fundisa for Change training programme brought diverse expertise and resources (material, cognitive, social and emotional) which were conducive to the achievement of programme outcomes. The programme’s action context (structure, culture, agency and relations) contributed to the achievement of programme outcomes by participants. Participants’ subject content knowledge, teaching practice and assessment practice was enhanced through attending the Fundisa for Change training. On-course tasks were mediated during training and this created opportunities for participants to discuss and reflect on current practice in ways that could lead to a change in practice. In evaluating professional development programmes, an elaborated definition of context in terms of structure, culture, agency and relations enables a comprehensive exploration of potential programme mechanisms that can be activated when programmes are implemented. It is also important to disaggregate resources and reasons when identifying mechanisms as this assists with differentiating between context and mechanisms. The study offers insights into the professional learning of teachers grappling with new content and pedagogical content knowledges related to environment in the context of recent curriculum changes where the South African national school curriculum has come into focus. Environmental education programmes in South Africa have implicitly used a realist approach. This study offers the first substantive professional learning evaluation that develops this approach explicitly using Theory of Change and Realist Evaluation in combination.
- Full Text:
- Date Issued: 2020
A trade union’s right to strike to acquire organisational rights
- Authors: Bebula, Vitamin Luxolo
- Date: 2020
- Subjects: Labor unions -- Law and legislation -- South Africa , Industrial relations -- South Africa South Africa -- Labour Relations Act -- 1995
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: http://hdl.handle.net/10948/48949 , vital:41565
- Description: Chapter II of the Labour Relations Act (LRA) entrenches the right to freedom of association. Section 1(c) of the LRA outlines the purpose of this Act as to provide a collective bargaining framework to determine wages, terms and conditions of employment, and matters of mutual interest by the employees and their unions and employers and employer’s organisation. Under this chapter, section (1)3 of the LRA confers the right to an employee to join a trade union, form or participate in forming a trade union or federation of trade unions. The member of a trade union has a right to participate in the lawful activities of his or her union. Regarding freedom of association, the new government took a commitment to uphold international labour standards and promised to submit to International Labour Organisation (ILO) Conventions on freedom of association and collective bargaining to parliament for ratification. In 1992 some provision of the previous Labour Relations Act was declared by ILO’s FFCC as incompatible with the freedom of association. The convention affords the workers and employers the right to establish and join organisations and federations of their own choice. The ILO also protects the right to collective bargaining. The convention also confers the right to provision of facilities to worker’s representatives for prompt and effective conduction of their activities.
- Full Text:
- Date Issued: 2020
- Authors: Bebula, Vitamin Luxolo
- Date: 2020
- Subjects: Labor unions -- Law and legislation -- South Africa , Industrial relations -- South Africa South Africa -- Labour Relations Act -- 1995
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: http://hdl.handle.net/10948/48949 , vital:41565
- Description: Chapter II of the Labour Relations Act (LRA) entrenches the right to freedom of association. Section 1(c) of the LRA outlines the purpose of this Act as to provide a collective bargaining framework to determine wages, terms and conditions of employment, and matters of mutual interest by the employees and their unions and employers and employer’s organisation. Under this chapter, section (1)3 of the LRA confers the right to an employee to join a trade union, form or participate in forming a trade union or federation of trade unions. The member of a trade union has a right to participate in the lawful activities of his or her union. Regarding freedom of association, the new government took a commitment to uphold international labour standards and promised to submit to International Labour Organisation (ILO) Conventions on freedom of association and collective bargaining to parliament for ratification. In 1992 some provision of the previous Labour Relations Act was declared by ILO’s FFCC as incompatible with the freedom of association. The convention affords the workers and employers the right to establish and join organisations and federations of their own choice. The ILO also protects the right to collective bargaining. The convention also confers the right to provision of facilities to worker’s representatives for prompt and effective conduction of their activities.
- Full Text:
- Date Issued: 2020
A trait-based approach to identify indicators for measuring rocky reef ecosystem condition in South Africa
- Authors: Smit, Kaylee
- Date: 2020
- Subjects: Environmental management -- Evaluation , Environmental monitoring -- Methodology Marine ecology -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/49292 , vital:41618
- Description: An important yet challenging task for effective ecosystem-based management of marine ecosystems is the reliable measurement and monitoring of changes in ecosystem condition. In South Africa, the National Biodiversity Assessment (NBA) has relied on cumulative pressure mapping, based on the calculation of cumulative impact scores, as a proxy for measures of marine ecosystem condition. While this method is practical for broad scale assessments where ecological data are lacking, there is a need to groundtruth this approach at local scales using in-situ data. The aim of this thesis was to identify potential indicators that can be used to measure the ecosystem condition of subtidal rocky reefs on the East coast of South Africa to groundtruth national pressure-based condition assessments. This thesis constituted the first attempt to conduct a comprehensive assessment of rocky reef ecosystem condition to validate national pressure-based assessments in South Africa. Based on a comprehensive literature review, a traits-based approach was selected to ensure that ecosystem structure and function were included in condition measurements. Fish and benthic community data were collected using baited remote underwater stereo-video systems (144 video samples) from the Natal Shelf ecoregion. Sampling spanned a gradient of low to high human pressures, which incorporated an effective Marine Protected Area (to define reference conditions), as well as areas exposed to intermediate levels of human pressures and a highly impacted area offshore of a large metropolitan port city. Structural and functional indicators were compared among localities and suitable functional indicators were aggregated into multimetric indices (MMIs) to provide an integrated measurement of ecosystem condition. Approximately 840 benthic biota and 10 400 fish (representing 176 identified fish species) were counted. Results showed that functional indicators, particularly size-based ones, were more effective at detecting changes in ecosystem condition compared with structural indicators based on taxonomy. Reefs in good ecological condition had a higher biomass of target species and a higher proportion of large predatory fish with more adults, compared with impacted areas. Benthic communities, however, appeared less responsive to cumulative pressures. The MMIs, using fish and benthic community data, were used to compare condition categories with those from the NBA. Results showed that the pressure-based assessments provided a reasonable proxy of broad patterns of rocky reef ecosystem condition. However, fine-scale discrepancies between results from the data-driven approach versus the proxy method suggested that broad-scale proxies might overestimate condition in some areas and underestimate it in others. To build on these results, the applicability of structural and functional indicators and MMIs were tested using an independent stereo-BRUVs dataset from the Agulhas Shelf ecoregion. Findings showed that not all MPAs were in good ecological condition compared with adjacent impacted areas, as was estimated by the NBA. However, there is a need to improve the quality of trait data and to test indicators and indices in other ecoregions, ecosystem types and in response to a broader range of improved pressure data. Furthermore, there is a need to apply innovative research to guide the calculation of thresholds for condition categories to advance condition assessments.
- Full Text:
- Date Issued: 2020
- Authors: Smit, Kaylee
- Date: 2020
- Subjects: Environmental management -- Evaluation , Environmental monitoring -- Methodology Marine ecology -- South Africa
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/49292 , vital:41618
- Description: An important yet challenging task for effective ecosystem-based management of marine ecosystems is the reliable measurement and monitoring of changes in ecosystem condition. In South Africa, the National Biodiversity Assessment (NBA) has relied on cumulative pressure mapping, based on the calculation of cumulative impact scores, as a proxy for measures of marine ecosystem condition. While this method is practical for broad scale assessments where ecological data are lacking, there is a need to groundtruth this approach at local scales using in-situ data. The aim of this thesis was to identify potential indicators that can be used to measure the ecosystem condition of subtidal rocky reefs on the East coast of South Africa to groundtruth national pressure-based condition assessments. This thesis constituted the first attempt to conduct a comprehensive assessment of rocky reef ecosystem condition to validate national pressure-based assessments in South Africa. Based on a comprehensive literature review, a traits-based approach was selected to ensure that ecosystem structure and function were included in condition measurements. Fish and benthic community data were collected using baited remote underwater stereo-video systems (144 video samples) from the Natal Shelf ecoregion. Sampling spanned a gradient of low to high human pressures, which incorporated an effective Marine Protected Area (to define reference conditions), as well as areas exposed to intermediate levels of human pressures and a highly impacted area offshore of a large metropolitan port city. Structural and functional indicators were compared among localities and suitable functional indicators were aggregated into multimetric indices (MMIs) to provide an integrated measurement of ecosystem condition. Approximately 840 benthic biota and 10 400 fish (representing 176 identified fish species) were counted. Results showed that functional indicators, particularly size-based ones, were more effective at detecting changes in ecosystem condition compared with structural indicators based on taxonomy. Reefs in good ecological condition had a higher biomass of target species and a higher proportion of large predatory fish with more adults, compared with impacted areas. Benthic communities, however, appeared less responsive to cumulative pressures. The MMIs, using fish and benthic community data, were used to compare condition categories with those from the NBA. Results showed that the pressure-based assessments provided a reasonable proxy of broad patterns of rocky reef ecosystem condition. However, fine-scale discrepancies between results from the data-driven approach versus the proxy method suggested that broad-scale proxies might overestimate condition in some areas and underestimate it in others. To build on these results, the applicability of structural and functional indicators and MMIs were tested using an independent stereo-BRUVs dataset from the Agulhas Shelf ecoregion. Findings showed that not all MPAs were in good ecological condition compared with adjacent impacted areas, as was estimated by the NBA. However, there is a need to improve the quality of trait data and to test indicators and indices in other ecoregions, ecosystem types and in response to a broader range of improved pressure data. Furthermore, there is a need to apply innovative research to guide the calculation of thresholds for condition categories to advance condition assessments.
- Full Text:
- Date Issued: 2020
A transportation management framework for the Polokwane local municipality during Zion Christian Church (ZCC) Easter weekend pilgrimage
- Authors: Mathebula, Andrew Mabila
- Date: 2020
- Subjects: Transportation -- Management , Urban transportation -- Planning Urban transportation -- Management Christian pilgrims and pilgrimages
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/46152 , vital:39509
- Description: The study investigated the impact of the high volume of vehicular traffic on pilgrims and the community during the Zion Christian Church (ZCC) Easter weekend pilgrimage. The researcher adopted an interpretivist research philosophy, and thus attempted to understand policy, planning, and management of the ZCC Easter pilgrimage through meanings that municipal officials assign to them. The study employed the action research approach by collaborating with the Polokwane Local Municipality (PLM) with a view to evolving lasting solutions to traffic congestion during the Easter weekend. The researchers used the seven-step model proposed by Van Tonder and Dietrichsen (Van Tonder and Dietrichsen, 2008). The justification of the model is that it is aligned with the action research model of Organisational Development (OD). It requires that a diagnosis process should be collaborative and participative towards offering solutions to organisational challenges as opposed to imposing a unilateral theoretical generated solution. This model also fits the ontological stance of the researchers which assumes that reality is co-constructed through engagement with other stakeholders. The researcher conducted semi-structured individual and focus groups discussion (FGD) using openended guides. The data from the informants were collected until a point of saturation. In addition to facilitation FGD discussion, the researcher made his own personal reflection of the participatory action research (PAR). A content analysis method was used to synthesise the qualitative data. The contents were extracted from transcribed interviews. The researcher carefully reviewed the notes several times and coded the notes independently. After that, the researcher coded the codes with each other for any potential contradiction. These codes were converted into themes and sub-themes. The qualitative content analysis process, led by the researcher, was both inductive and deductive. Prior to the inductive process, the researcher listened carefully to the audio recordings transcriptions to get a general understanding of participants’ experiences. The findings indicate that the South African transportation planning approach is ossified and divorced from reality. There is a lacuna to address peak traffic challenges during the Easter weekend and the festive season. It is notable that the government-led seasonal road safety campaigns such as ‘Arrive Alive’ are curiously inadequate to address peak traffic and road accidents challenges in South Africa during the ZCC Easter pilgrimage. The transportation management framework for the PLM as well as a peak traffic standard were developed as part of the study recommendations. These recommendations augur a shift to transport planning in South Africa.
- Full Text:
- Date Issued: 2020
- Authors: Mathebula, Andrew Mabila
- Date: 2020
- Subjects: Transportation -- Management , Urban transportation -- Planning Urban transportation -- Management Christian pilgrims and pilgrimages
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/46152 , vital:39509
- Description: The study investigated the impact of the high volume of vehicular traffic on pilgrims and the community during the Zion Christian Church (ZCC) Easter weekend pilgrimage. The researcher adopted an interpretivist research philosophy, and thus attempted to understand policy, planning, and management of the ZCC Easter pilgrimage through meanings that municipal officials assign to them. The study employed the action research approach by collaborating with the Polokwane Local Municipality (PLM) with a view to evolving lasting solutions to traffic congestion during the Easter weekend. The researchers used the seven-step model proposed by Van Tonder and Dietrichsen (Van Tonder and Dietrichsen, 2008). The justification of the model is that it is aligned with the action research model of Organisational Development (OD). It requires that a diagnosis process should be collaborative and participative towards offering solutions to organisational challenges as opposed to imposing a unilateral theoretical generated solution. This model also fits the ontological stance of the researchers which assumes that reality is co-constructed through engagement with other stakeholders. The researcher conducted semi-structured individual and focus groups discussion (FGD) using openended guides. The data from the informants were collected until a point of saturation. In addition to facilitation FGD discussion, the researcher made his own personal reflection of the participatory action research (PAR). A content analysis method was used to synthesise the qualitative data. The contents were extracted from transcribed interviews. The researcher carefully reviewed the notes several times and coded the notes independently. After that, the researcher coded the codes with each other for any potential contradiction. These codes were converted into themes and sub-themes. The qualitative content analysis process, led by the researcher, was both inductive and deductive. Prior to the inductive process, the researcher listened carefully to the audio recordings transcriptions to get a general understanding of participants’ experiences. The findings indicate that the South African transportation planning approach is ossified and divorced from reality. There is a lacuna to address peak traffic challenges during the Easter weekend and the festive season. It is notable that the government-led seasonal road safety campaigns such as ‘Arrive Alive’ are curiously inadequate to address peak traffic and road accidents challenges in South Africa during the ZCC Easter pilgrimage. The transportation management framework for the PLM as well as a peak traffic standard were developed as part of the study recommendations. These recommendations augur a shift to transport planning in South Africa.
- Full Text:
- Date Issued: 2020
A tribute to you
- Ndlebe-September, Thobeka Veronica
- Authors: Ndlebe-September, Thobeka Veronica
- Date: 2020
- Subjects: South African fiction (English) -- 21st century , South African fiction (English) -- History and criticism , Short stories, South African (English) -- 21st century , Xhosa fiction -- 21st century , Xhosa fiction -- History and criticism , Short stories, Xhosa -- 21st century , Diaries -- Authorship
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/144989 , vital:38398
- Description: My collection of short stories reflects my interest in narrative biblical fiction, allegorical stories about people and nature that resonate with our daily lives. I have been greatly influenced by writers such as Joel Matlou, Flannery O’Connor, Barry Gifford, Miriam Tladi and Leah Harris amongst others. I have also been captivated by fairy tales and folk tales, and also the work of isiXhosa writers such as S. E. K. Mqhayi, Madiponi Masenya, and Hulisani Ramantswana. I have discovered that I can borrow certain styles and forms of writing to enhance my own stories which are situated within ‘local’ contexts such as education, poverty, employment, the body, life and death.
- Full Text:
- Date Issued: 2020
- Authors: Ndlebe-September, Thobeka Veronica
- Date: 2020
- Subjects: South African fiction (English) -- 21st century , South African fiction (English) -- History and criticism , Short stories, South African (English) -- 21st century , Xhosa fiction -- 21st century , Xhosa fiction -- History and criticism , Short stories, Xhosa -- 21st century , Diaries -- Authorship
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/144989 , vital:38398
- Description: My collection of short stories reflects my interest in narrative biblical fiction, allegorical stories about people and nature that resonate with our daily lives. I have been greatly influenced by writers such as Joel Matlou, Flannery O’Connor, Barry Gifford, Miriam Tladi and Leah Harris amongst others. I have also been captivated by fairy tales and folk tales, and also the work of isiXhosa writers such as S. E. K. Mqhayi, Madiponi Masenya, and Hulisani Ramantswana. I have discovered that I can borrow certain styles and forms of writing to enhance my own stories which are situated within ‘local’ contexts such as education, poverty, employment, the body, life and death.
- Full Text:
- Date Issued: 2020
A Veblenian Dichotomy re-examination of labour brokerage and South African labour market functionality
- Authors: Haaketa, Bernadatte Tina
- Date: 2020
- Subjects: Veblen, Thorstein, 1857-1929 , Contracting out -- South Africa , Temporary employment -- South Africa , Industrial relations -- South Africa , Labor supply -- South Africa , Labor supply -- Effect of technological innovations on -- South Africa , Manpower policy -- South Africa , Labor market -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/168446 , vital:41583
- Description: Labour markets ar ound the world have witnessed a great change in labour relations. The introduction of globa lisation, increased competition and technological advancements has caused business organisations to change their employment methods. While trying to survive and remain profitable, employers have adopted a new form of triangular employment relationship. Thi s form of employment relationship known as labour broking and which forms part of the Temporary Employment Services (TES) involves a relationship between the worker, labour agent (broker) and a client c ompany. Although it may seem like a good strategy for business organisations, the change in employment relationships has had negative effects and contributed to labour market dysfunctionalities . This has resulted in critics of labour broking calling or an end in labour broking and supporters of labour broking asking for better regulation of the industry. Labour markets are me When it comes to analysing labour broking and its impact on labour market functionality in South Africa. Scholars and analysts such as Budlender ( 2013 ) and Bhorat, Lil enstein, Oosthuizen , and Thornton ( 2016 ) have used the Neoclassical , New Institutional Economics and Marxist approach es. The current views on labour broking and the current schools of thought fail to look at the underlying behavioural aspect of labour brokers and the client c ompanies. Hence making it easy for labour brokers and their client companies to continue with their unscrupulous activities. However, this t hesis adapted the Veblenian Dichotomy framework which focuses on understanding the role of the evolutionary proce ss and the role of institutions in shaping economic behaviour. The Veblenian dichotomy shows that power plays an important role in how labour markets are run. Similarly, behaviour also influences the manner in which labour brokers and client companies trea t workers. And lastly the Veblenian dichotomy shows that in order for the industry to be run better there has to be change in the behaviour and cultu re of the labour brokers and client companies . This view allows for deeper analysis of the reasons for the flour ishing nature of labour broking and the rationale behind the behaviour of economic players and attempts to provide solutions on how labour brok ing can be correctly administered in South Africa. The Veblenian Dichotomy categorises institutions into t wo sets, namely the ceremonial institutions and instrumental institutions. Where Ceremonial institutions are said to be institutions that foster the interests of business such as profitability and earning of free income, even if there is no corresponding i ncrease in production. While Instrumental institutions, usually working through the influence of technology, address the interests of the common pers on and the labourer as well as business (Waller, 1982; Foster, 1981; Veblen, 1919). These two systems of va lues and institutions are antagonistic and the relative strength of one to the other determines economic outcomes and in whose interests the outcomes would be (Waller, 1982; Foster, 1981; Veblen, 1919). The Veblenian Dichotomy further looks at ceremonial encapsulation which occurs when ceremonial systems prevail over instrumental systems. Ceremonial encapsulation presents the hypothesis that the insti tutional structure will absorb new technology only to the extent that it can do so without disrupting the e xisting value structure (Waller, 1987; Bush, 1979.) The thesis use d various sources , such as working papers, public hearings, court cases, trade union submissions, integrated reports from companies, employee submissions and media publications on the debate about labour broking whether labour broking and applied the Interpretative Phenomenological Analysi s (IPA) research approach, in the process of data collection and analysis . The thesis further applied thematic analysis to derive themes that would be used to analyse the impact of labour broking on labour market functionality in South Africa. The emergent themes and subthemes were Exploitative lab our relations subthemes; job Insecurity, increased financial burden and no skills development. The second theme was; Competitive advantage and the subthemes were; i ncreased profits and organisational efficiency. The third theme was l abour market efficiency and the subthemes were. E mployment creation and labour market flexibility. And, the last theme was a mbiguous l abour regulation s with subthemes; n o freedom of association and a tool for circumventing labour regulations . Lastly, Tool’s (1994) criteria of j udgement for institutional adjustments was used to evaluate the emergent themes and to evaluate the impact of l abour broking on the overall welfare of individuals, which includes determining whether employees in the TES sector gain skills and improved stan dards of living. The findings of the research the TES sector is characterised by ceremonial values. Ceremonial values (as mentioned in section 3.3) are those values that are warranted by the ways of life that prescribe status and hierarchies and unpleasant distinctions to apply value and status on other people (Bush, 1987, 1988; Ayres, 1967). Thus changing the way in which labour brokers conduct themselves or handle labour broking activities would prove to be difficult . T he power that is mostly used in TES employment sectors is condign power. Condign power is explained as the form of power that is predominantly used in ceremonially encapsulated markets. And it involves making use of punishment or fear in order to get people to do something. This is because w orkers in the TES sector are forced to submit to conditions that they would not normally have submitted to if t hey did not have a fear of losing their jobs. This supports existing literature which shows that in the TES sector, TES employers use force and p ower in order to get the workers to do something, and this results in a master - servant relationship between the employer and the employee. Furthermore, the protests that erupt in the TES sector agree with Marxist theory which notes that the frustrations in the way workers are treated would result in a revolution of the working class against the employers. However, now, workers have not been able to overcome the employers and take over the industry. In addition to what current literature says, the research found that some managers make use of labour broking as a way of manifesting their exploitative characteristics on the labour market, thus creating information asymmetries in order to advance their own personal needs. Situations such as these reve al characteristics of opportunistic behaviour, which is perpetuated by the imperfect flow of information. This means th at the market is imperfect, and imperfect markets are characteristics of dysfunctional labour markets. The research also found that it i s the South African Constitution that protects labour brokers and client companies from accounting for the unfair treatm ent of workers. Labour brokers and client companies rely on the South African Constitution to defend them when it comes to banning labou r broking. This is because section 22 of the Constitution talks about the right of every individual to trade freely in S outh Africa (Kutumela, 2015). When institutional adjustments do not meet the requirements of the progressive criteria, it means they are regressive. Based on the data that was collected and the responses and remarks of the workers, trade unions, and trade union federations, it can be said that TES employment and labour broking hinders labour market functionality. Hence, it can be concluded that, due to the characteristics mentioned, labour broking does indeed have a regressive element which hinders labour m arket functionality. An area for further research for TES employment would be to look at the impact of the amendments to the Labour Rela tions Act. Specifically focusing on the Constitutional Court ruling, which forces labour brokers to treat employees who have been employed for longer than three months as permanent employees.
- Full Text:
- Date Issued: 2020
- Authors: Haaketa, Bernadatte Tina
- Date: 2020
- Subjects: Veblen, Thorstein, 1857-1929 , Contracting out -- South Africa , Temporary employment -- South Africa , Industrial relations -- South Africa , Labor supply -- South Africa , Labor supply -- Effect of technological innovations on -- South Africa , Manpower policy -- South Africa , Labor market -- South Africa
- Language: English
- Type: text , Thesis , Masters , MCom
- Identifier: http://hdl.handle.net/10962/168446 , vital:41583
- Description: Labour markets ar ound the world have witnessed a great change in labour relations. The introduction of globa lisation, increased competition and technological advancements has caused business organisations to change their employment methods. While trying to survive and remain profitable, employers have adopted a new form of triangular employment relationship. Thi s form of employment relationship known as labour broking and which forms part of the Temporary Employment Services (TES) involves a relationship between the worker, labour agent (broker) and a client c ompany. Although it may seem like a good strategy for business organisations, the change in employment relationships has had negative effects and contributed to labour market dysfunctionalities . This has resulted in critics of labour broking calling or an end in labour broking and supporters of labour broking asking for better regulation of the industry. Labour markets are me When it comes to analysing labour broking and its impact on labour market functionality in South Africa. Scholars and analysts such as Budlender ( 2013 ) and Bhorat, Lil enstein, Oosthuizen , and Thornton ( 2016 ) have used the Neoclassical , New Institutional Economics and Marxist approach es. The current views on labour broking and the current schools of thought fail to look at the underlying behavioural aspect of labour brokers and the client c ompanies. Hence making it easy for labour brokers and their client companies to continue with their unscrupulous activities. However, this t hesis adapted the Veblenian Dichotomy framework which focuses on understanding the role of the evolutionary proce ss and the role of institutions in shaping economic behaviour. The Veblenian dichotomy shows that power plays an important role in how labour markets are run. Similarly, behaviour also influences the manner in which labour brokers and client companies trea t workers. And lastly the Veblenian dichotomy shows that in order for the industry to be run better there has to be change in the behaviour and cultu re of the labour brokers and client companies . This view allows for deeper analysis of the reasons for the flour ishing nature of labour broking and the rationale behind the behaviour of economic players and attempts to provide solutions on how labour brok ing can be correctly administered in South Africa. The Veblenian Dichotomy categorises institutions into t wo sets, namely the ceremonial institutions and instrumental institutions. Where Ceremonial institutions are said to be institutions that foster the interests of business such as profitability and earning of free income, even if there is no corresponding i ncrease in production. While Instrumental institutions, usually working through the influence of technology, address the interests of the common pers on and the labourer as well as business (Waller, 1982; Foster, 1981; Veblen, 1919). These two systems of va lues and institutions are antagonistic and the relative strength of one to the other determines economic outcomes and in whose interests the outcomes would be (Waller, 1982; Foster, 1981; Veblen, 1919). The Veblenian Dichotomy further looks at ceremonial encapsulation which occurs when ceremonial systems prevail over instrumental systems. Ceremonial encapsulation presents the hypothesis that the insti tutional structure will absorb new technology only to the extent that it can do so without disrupting the e xisting value structure (Waller, 1987; Bush, 1979.) The thesis use d various sources , such as working papers, public hearings, court cases, trade union submissions, integrated reports from companies, employee submissions and media publications on the debate about labour broking whether labour broking and applied the Interpretative Phenomenological Analysi s (IPA) research approach, in the process of data collection and analysis . The thesis further applied thematic analysis to derive themes that would be used to analyse the impact of labour broking on labour market functionality in South Africa. The emergent themes and subthemes were Exploitative lab our relations subthemes; job Insecurity, increased financial burden and no skills development. The second theme was; Competitive advantage and the subthemes were; i ncreased profits and organisational efficiency. The third theme was l abour market efficiency and the subthemes were. E mployment creation and labour market flexibility. And, the last theme was a mbiguous l abour regulation s with subthemes; n o freedom of association and a tool for circumventing labour regulations . Lastly, Tool’s (1994) criteria of j udgement for institutional adjustments was used to evaluate the emergent themes and to evaluate the impact of l abour broking on the overall welfare of individuals, which includes determining whether employees in the TES sector gain skills and improved stan dards of living. The findings of the research the TES sector is characterised by ceremonial values. Ceremonial values (as mentioned in section 3.3) are those values that are warranted by the ways of life that prescribe status and hierarchies and unpleasant distinctions to apply value and status on other people (Bush, 1987, 1988; Ayres, 1967). Thus changing the way in which labour brokers conduct themselves or handle labour broking activities would prove to be difficult . T he power that is mostly used in TES employment sectors is condign power. Condign power is explained as the form of power that is predominantly used in ceremonially encapsulated markets. And it involves making use of punishment or fear in order to get people to do something. This is because w orkers in the TES sector are forced to submit to conditions that they would not normally have submitted to if t hey did not have a fear of losing their jobs. This supports existing literature which shows that in the TES sector, TES employers use force and p ower in order to get the workers to do something, and this results in a master - servant relationship between the employer and the employee. Furthermore, the protests that erupt in the TES sector agree with Marxist theory which notes that the frustrations in the way workers are treated would result in a revolution of the working class against the employers. However, now, workers have not been able to overcome the employers and take over the industry. In addition to what current literature says, the research found that some managers make use of labour broking as a way of manifesting their exploitative characteristics on the labour market, thus creating information asymmetries in order to advance their own personal needs. Situations such as these reve al characteristics of opportunistic behaviour, which is perpetuated by the imperfect flow of information. This means th at the market is imperfect, and imperfect markets are characteristics of dysfunctional labour markets. The research also found that it i s the South African Constitution that protects labour brokers and client companies from accounting for the unfair treatm ent of workers. Labour brokers and client companies rely on the South African Constitution to defend them when it comes to banning labou r broking. This is because section 22 of the Constitution talks about the right of every individual to trade freely in S outh Africa (Kutumela, 2015). When institutional adjustments do not meet the requirements of the progressive criteria, it means they are regressive. Based on the data that was collected and the responses and remarks of the workers, trade unions, and trade union federations, it can be said that TES employment and labour broking hinders labour market functionality. Hence, it can be concluded that, due to the characteristics mentioned, labour broking does indeed have a regressive element which hinders labour m arket functionality. An area for further research for TES employment would be to look at the impact of the amendments to the Labour Rela tions Act. Specifically focusing on the Constitutional Court ruling, which forces labour brokers to treat employees who have been employed for longer than three months as permanent employees.
- Full Text:
- Date Issued: 2020
A vision based multirotor aircraft for use in the security industry
- Authors: Nelson, Benjamin David
- Date: 2020
- Subjects: Drone aircraft -- South Africa , Mechatronics -- Research
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/46816 , vital:39664
- Description: This research consisted of developing a vision based multirotor aircraft that could be used in the security industry. A second-hand aircraft was purchased and modified. The aircraft made use of a Pixhawk flight controller and a Odroid XU4 companion computer, which resulted in the computer injecting commands into the flight controller. Robot Operating System was installed and used on the companion computer to integrate the vision system and the aircraft. The vision system was designed to help develop a landing system where the aircraft would land on an ArUco marker. The vision system also allowed the aircraft to detect and follow humans. A Software in the Loop (SITL) was run alongside Gazebo, allowing the developed landing system and the human detecting system to be simulated and tested. The developed landing system was implemented on the aircraft, where the developed landing system was tested and compared to the aircraft’s current GPS based landing system. The developed landing system obtained a better overall accuracy , while also taking longer to land the aircraft compared to the GPS based landing system. There were also numerous manual and autonomous test flights implemented on the aircraft.
- Full Text:
- Date Issued: 2020
- Authors: Nelson, Benjamin David
- Date: 2020
- Subjects: Drone aircraft -- South Africa , Mechatronics -- Research
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/46816 , vital:39664
- Description: This research consisted of developing a vision based multirotor aircraft that could be used in the security industry. A second-hand aircraft was purchased and modified. The aircraft made use of a Pixhawk flight controller and a Odroid XU4 companion computer, which resulted in the computer injecting commands into the flight controller. Robot Operating System was installed and used on the companion computer to integrate the vision system and the aircraft. The vision system was designed to help develop a landing system where the aircraft would land on an ArUco marker. The vision system also allowed the aircraft to detect and follow humans. A Software in the Loop (SITL) was run alongside Gazebo, allowing the developed landing system and the human detecting system to be simulated and tested. The developed landing system was implemented on the aircraft, where the developed landing system was tested and compared to the aircraft’s current GPS based landing system. The developed landing system obtained a better overall accuracy , while also taking longer to land the aircraft compared to the GPS based landing system. There were also numerous manual and autonomous test flights implemented on the aircraft.
- Full Text:
- Date Issued: 2020
Absent fathers: psychological and socio-economic implications for black children and directions for future research
- Magqamfana, Simnikiwe H, Bazana, Sandiso
- Authors: Magqamfana, Simnikiwe H , Bazana, Sandiso
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163443 , vital:41038 , DOI: 10.1080/14330237.2020.1744299
- Description: This study investigated fathers’ absence influences on the self-perceptions of South African young adults. Informants were five black university students (two females, three males; age range 20 to 28 years). They responded to semi-structured face-to-face interviews on self-perceptions from having matured in the absence of their biological fathers. Thematic analysis of the data revealed that the informants consider the father-absence when they grapple with material well-being shortage. Participants had mixed perceptions about the psychosocial effects on them from father-absence, with some believing to be thriving despite a history of father-absence. Overall, the findings suggest a need for caution in pathologising young adults with a history of father-absence as necessarily deprived.
- Full Text:
- Date Issued: 2020
- Authors: Magqamfana, Simnikiwe H , Bazana, Sandiso
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/163443 , vital:41038 , DOI: 10.1080/14330237.2020.1744299
- Description: This study investigated fathers’ absence influences on the self-perceptions of South African young adults. Informants were five black university students (two females, three males; age range 20 to 28 years). They responded to semi-structured face-to-face interviews on self-perceptions from having matured in the absence of their biological fathers. Thematic analysis of the data revealed that the informants consider the father-absence when they grapple with material well-being shortage. Participants had mixed perceptions about the psychosocial effects on them from father-absence, with some believing to be thriving despite a history of father-absence. Overall, the findings suggest a need for caution in pathologising young adults with a history of father-absence as necessarily deprived.
- Full Text:
- Date Issued: 2020
Academic readiness of students for higher education: a case for academic support at Rhodes University
- Authors: Khoza, Lebogang Peter
- Date: 2020
- Subjects: College student development programs -- South Africa -- Makhanda , Dropouts -- Prevention , College students -- South Africa-- Makhanda -- Social conditions , School failure -- South Africa -- Makhanda , Academic achievement-- South Africa -- Makhanda , Student adjustment -- South Africa -- Makhanda , Counseling in higher education -- South Africa -- Makhanda , Student Integration Model , Conceptual Framework Model , Geometric Design of Student Persistence
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: http://hdl.handle.net/10962/147848 , vital:38678
- Description: The worrying existence of incidences of student retention, poor pass rates and an increase in repetition rates is a cause for concern for institutions of higher learning in South Africa. The problem of student retention is not new in our institutions of higher learning. Support structures, strategies, and policies need to be developed for different academic and social challenges that students face daily. This study explores the need for academic support at Rhodes University; it also explores the internal and external problems that students face, the perceptions and experiences of students on academic support available to them. The study implemented a narrative research approach implanted within a qualitative research framework. Data was collected through a questionnaire, and narrative interviews. Tinto’s Student Integration Model was used to analyse the data in this study and was supplemented by Louw’s conceptual framework model and Swail’s Geometric Design of Student Persistence. These three models position the student experience as the foundation for academic support programmes and development. The study argues that as long as effective and adequate academic support is lacking, students will continue to experience difficulties in completing their studies. The findings from the study reveal that at present, Rhodes University provides support to students who are in extended studies. However, this support system disadvantages many students, notably those not in the extended studies programme. As a result, such students are not supported through strategies and structures that extended studies students receive. Furthermore, the data generates internal and external problems that student face daily, as a result, the findings showed that there is a need for academic support at Rhodes. The study recommends that Rhodes University must establish an academic unit that will provide academic support to all students registered in the university.
- Full Text:
- Date Issued: 2020
- Authors: Khoza, Lebogang Peter
- Date: 2020
- Subjects: College student development programs -- South Africa -- Makhanda , Dropouts -- Prevention , College students -- South Africa-- Makhanda -- Social conditions , School failure -- South Africa -- Makhanda , Academic achievement-- South Africa -- Makhanda , Student adjustment -- South Africa -- Makhanda , Counseling in higher education -- South Africa -- Makhanda , Student Integration Model , Conceptual Framework Model , Geometric Design of Student Persistence
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: http://hdl.handle.net/10962/147848 , vital:38678
- Description: The worrying existence of incidences of student retention, poor pass rates and an increase in repetition rates is a cause for concern for institutions of higher learning in South Africa. The problem of student retention is not new in our institutions of higher learning. Support structures, strategies, and policies need to be developed for different academic and social challenges that students face daily. This study explores the need for academic support at Rhodes University; it also explores the internal and external problems that students face, the perceptions and experiences of students on academic support available to them. The study implemented a narrative research approach implanted within a qualitative research framework. Data was collected through a questionnaire, and narrative interviews. Tinto’s Student Integration Model was used to analyse the data in this study and was supplemented by Louw’s conceptual framework model and Swail’s Geometric Design of Student Persistence. These three models position the student experience as the foundation for academic support programmes and development. The study argues that as long as effective and adequate academic support is lacking, students will continue to experience difficulties in completing their studies. The findings from the study reveal that at present, Rhodes University provides support to students who are in extended studies. However, this support system disadvantages many students, notably those not in the extended studies programme. As a result, such students are not supported through strategies and structures that extended studies students receive. Furthermore, the data generates internal and external problems that student face daily, as a result, the findings showed that there is a need for academic support at Rhodes. The study recommends that Rhodes University must establish an academic unit that will provide academic support to all students registered in the university.
- Full Text:
- Date Issued: 2020
Acceptance of ambulatory blood pressure monitoring in a semi-rural population in South Africa:
- Chiwanza, Farisai, Irwin, Yoland, Dowse, Roslind
- Authors: Chiwanza, Farisai , Irwin, Yoland , Dowse, Roslind
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157072 , vital:40084 , DOI: https://doi.org/10.4102/hsag.v25i0.1336
- Description: Ambulatory blood pressure monitoring is a valuable tool that helps in providing an insight into the diagnosis and management of hypertension; however, no evidence exists of its acceptance in the diverse South African population. We assessed the acceptance of an ambulatory blood pressure monitor in patients attending public sector primary health care (PHC) clinics. Five PHC clinics in the Makana subdistrict in the Eastern Cape.
- Full Text:
- Date Issued: 2020
- Authors: Chiwanza, Farisai , Irwin, Yoland , Dowse, Roslind
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/157072 , vital:40084 , DOI: https://doi.org/10.4102/hsag.v25i0.1336
- Description: Ambulatory blood pressure monitoring is a valuable tool that helps in providing an insight into the diagnosis and management of hypertension; however, no evidence exists of its acceptance in the diverse South African population. We assessed the acceptance of an ambulatory blood pressure monitor in patients attending public sector primary health care (PHC) clinics. Five PHC clinics in the Makana subdistrict in the Eastern Cape.
- Full Text:
- Date Issued: 2020
Access to social grants information by the Balfour Village elderly population in Eastern Cape Province, South Africa
- Authors: Faku, Andile
- Date: 2020
- Subjects: Information services Information resources
- Language: English
- Type: Thesis , Masters , MSoc. Sci (Library and Information Science)
- Identifier: http://hdl.handle.net/10353/18096 , vital:42231
- Description: This study sought to investigate the access to information about social grants by the elderly population of Balfour village in Raymond Mhlaba Local Municipality in SA’s Eastern Cape Province. A study on access to information is quite relevant in the knowledge-based economies. People act when they have information and similarly elderly people require information in order to access their grants. This study is quite relevant in the Library and Information Science field. The targeted population for the study were the elderly people of the Balfour village. The qualitative research approach was used in this study. The researcher selected a sample for the study using snowballsampling procedure. Both in-depth interviews and questionnaires were employed as methods of gathering data and thematic analysis of data was used. Results showed that there is a lack of information dissemination and access to information about social grants for elderly people living in Balfour. The study found out that elderly people in Balfour complained that, in most cases, they were not sure about the documents they were supposed to bring with them when they visited the South African Social Security Agency offices. This indicates the need for SASSA to train their staff members to be customer orientated and encourage staff to empower themselves with formal educational qualifications. In addition, the distance to and from SASSA offices is of great concern because elderly people spend significant amounts of money for travelling these distances. Therefore, there must be an office that is situated in a favourable distance to the elderly so that they do not struggle when they want to reach SASSA offices. Another option would be to avail a mobile office that may serve the area two or three times a week.
- Full Text:
- Date Issued: 2020
- Authors: Faku, Andile
- Date: 2020
- Subjects: Information services Information resources
- Language: English
- Type: Thesis , Masters , MSoc. Sci (Library and Information Science)
- Identifier: http://hdl.handle.net/10353/18096 , vital:42231
- Description: This study sought to investigate the access to information about social grants by the elderly population of Balfour village in Raymond Mhlaba Local Municipality in SA’s Eastern Cape Province. A study on access to information is quite relevant in the knowledge-based economies. People act when they have information and similarly elderly people require information in order to access their grants. This study is quite relevant in the Library and Information Science field. The targeted population for the study were the elderly people of the Balfour village. The qualitative research approach was used in this study. The researcher selected a sample for the study using snowballsampling procedure. Both in-depth interviews and questionnaires were employed as methods of gathering data and thematic analysis of data was used. Results showed that there is a lack of information dissemination and access to information about social grants for elderly people living in Balfour. The study found out that elderly people in Balfour complained that, in most cases, they were not sure about the documents they were supposed to bring with them when they visited the South African Social Security Agency offices. This indicates the need for SASSA to train their staff members to be customer orientated and encourage staff to empower themselves with formal educational qualifications. In addition, the distance to and from SASSA offices is of great concern because elderly people spend significant amounts of money for travelling these distances. Therefore, there must be an office that is situated in a favourable distance to the elderly so that they do not struggle when they want to reach SASSA offices. Another option would be to avail a mobile office that may serve the area two or three times a week.
- Full Text:
- Date Issued: 2020
Accessibility of agricultural information by smallholder farmers in Amatole District Municipality: Nexus between agricultural extension services and the library
- Authors: Sigigaba, Masimthembe
- Date: 2020
- Subjects: Farms, Small
- Language: English
- Type: Thesis , Masters , M Agric (Agric Extension)
- Identifier: http://hdl.handle.net/10353/18849 , vital:42870
- Description: Accessibility to relevant, accurate and timely information remains vital in farming. For farmers to improve their productivity they depend on access to pertinent agricultural information. Such information updated them about new agricultural technologies, climate change, new cultivars, access to market and access to financial assistance. These types of information help farmers in decision making regarding their farming. Agricultural extension officers remain a reliable source where farmers could obtain relevant agricultural information. Community libraries are also channels that could be used by agricultural extension officers to complement their work of providing farmers with information. Thus, the study sought to assess linkage between these two institutions to provide farmers with information. A positivism paradigm with quantitative research approach were adopted in the study. Smallholder farmers (169), agricultural extension officers (5) and librarians (15) were the unit of analysis. A semi-structured questionnaire was used for data collection and SPSS software for analysis. Findings revealed that, agricultural extension officers mostly utilise interpersonal channels that include demonstrations, group meetings and face-to-face interaction to provide farmers with information. Community libraries were found to be non-utilised by extension services and also by farmers. Farmers were of the perception that libraries are meant for educated people. It was also discovered that community libraries have information on agriculture that only targets learners who are taking agriculture in school as a subject. There was no existing linkage between agricultural extension services and community libraries working together to provide farmers with pertinent agricultural information that can help them improve productivity
- Full Text:
- Date Issued: 2020
- Authors: Sigigaba, Masimthembe
- Date: 2020
- Subjects: Farms, Small
- Language: English
- Type: Thesis , Masters , M Agric (Agric Extension)
- Identifier: http://hdl.handle.net/10353/18849 , vital:42870
- Description: Accessibility to relevant, accurate and timely information remains vital in farming. For farmers to improve their productivity they depend on access to pertinent agricultural information. Such information updated them about new agricultural technologies, climate change, new cultivars, access to market and access to financial assistance. These types of information help farmers in decision making regarding their farming. Agricultural extension officers remain a reliable source where farmers could obtain relevant agricultural information. Community libraries are also channels that could be used by agricultural extension officers to complement their work of providing farmers with information. Thus, the study sought to assess linkage between these two institutions to provide farmers with information. A positivism paradigm with quantitative research approach were adopted in the study. Smallholder farmers (169), agricultural extension officers (5) and librarians (15) were the unit of analysis. A semi-structured questionnaire was used for data collection and SPSS software for analysis. Findings revealed that, agricultural extension officers mostly utilise interpersonal channels that include demonstrations, group meetings and face-to-face interaction to provide farmers with information. Community libraries were found to be non-utilised by extension services and also by farmers. Farmers were of the perception that libraries are meant for educated people. It was also discovered that community libraries have information on agriculture that only targets learners who are taking agriculture in school as a subject. There was no existing linkage between agricultural extension services and community libraries working together to provide farmers with pertinent agricultural information that can help them improve productivity
- Full Text:
- Date Issued: 2020
Acetophenone substituted phthalocyanines and their graphene quantum dots conjugates as photosensitizers for photodynamic antimicrobial chemotherapy against Staphylococcus aureus
- Openda, Yolande I, Sen, Pinar, Managa, Muthumuni, Nyokong, Tebello
- Authors: Openda, Yolande I , Sen, Pinar , Managa, Muthumuni , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186507 , vital:44506 , xlink:href="https://doi.org/10.1016/j.pdpdt.2019.101607"
- Description: This work reports on the synthesis and characterization of novel acetophenone substituted phthalocyanines along with the self-assembled nanoconjugates formed via π-π stacking interaction between the synthesized unmetalated (2), zinc (3) and indium (4) phthalocyanines and graphene quantum dots (GQDs) to form 2@GQDs, 3@GQDs and 4@GQDs. The complexes and conjugates exhibited high singlet oxygen ranging from 0.20 to 0.79 in DMSO for Pcs and nanoconjugates where in all cases, the indium complexes showed the highest singlet oxygen quantum yields. The photodynamic antimicrobial chemotherapy activity of both phthalocyanines and nanoconjugates were tested against Staphylococcus aureus. 4@GQDs was found to be highly effective causing a 9.68 log reduction of the bacteria at 10 μM (based on Pc) when compared to 3.77 log reduction of 3@GQDs.
- Full Text:
- Date Issued: 2020
- Authors: Openda, Yolande I , Sen, Pinar , Managa, Muthumuni , Nyokong, Tebello
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/186507 , vital:44506 , xlink:href="https://doi.org/10.1016/j.pdpdt.2019.101607"
- Description: This work reports on the synthesis and characterization of novel acetophenone substituted phthalocyanines along with the self-assembled nanoconjugates formed via π-π stacking interaction between the synthesized unmetalated (2), zinc (3) and indium (4) phthalocyanines and graphene quantum dots (GQDs) to form 2@GQDs, 3@GQDs and 4@GQDs. The complexes and conjugates exhibited high singlet oxygen ranging from 0.20 to 0.79 in DMSO for Pcs and nanoconjugates where in all cases, the indium complexes showed the highest singlet oxygen quantum yields. The photodynamic antimicrobial chemotherapy activity of both phthalocyanines and nanoconjugates were tested against Staphylococcus aureus. 4@GQDs was found to be highly effective causing a 9.68 log reduction of the bacteria at 10 μM (based on Pc) when compared to 3.77 log reduction of 3@GQDs.
- Full Text:
- Date Issued: 2020
Activity of diverse chalcones against several targets: statistical analysis of a high-throughput virtual screen of a custom chalcone library
- Authors: Sarron, Arthur F D
- Date: 2020
- Subjects: Acetophenone , Benzaldehyde , Ketones , Pyruvate kinase , Drug development , Aromatic compounds , Heat shock proteins
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/116028 , vital:34291
- Description: Chalcone family molecules are well known to have therapeutic proprieties (anti-inflammatory, anti-microbial or anti-cancer, etc). However the mechanism of action in some cases is not well known. A virtual library of this family of compounds was constructed using custom scripts, based on the aldol condensation, and this library was modified further to analogues by expansion of the α,β-unsaturated ketone linker. Acetophenone and benzaldehyde derivatives which are available and purchasable were used as a base to design the chalcone virtual library. 8063 chalcones were constructed and geometrically optimized with Gaussian 09. Their physicochemical characteristics linked to the Lipinski rules were analyzed with Knime and CDK. The entire library was after docked against several targets including HIV-1 integrase, MRSA pyruvate kinase, HSP90, COX-1, COX-2, ALR2, MAOA, MAOB, acetylcholinesterase, butyrylcholinesterase and PLA2. With the exception of MAOA, which does not have a crystal structure ligand, all dockings were validated by redocking the original ligand provided by the literature. These targets are known in the literature to be inhibited by chalcone-derivatives. However, specificity of the particular known chalcone inhibitors to the particular targets is not known. To this end the performance of the generated chalcone library against the list of targets was of interest. The binding energy of ligand-protein complexes was generally good across the library. Statistical analysis including principal component analysis and hierarchical clustering analysis were made in order to investigate for any physical/chemical characteristics which might explain what chalcone features affect the binding energy of the ligand-protein complexes. The spherical polar coordinates defining the orientation of the binding poses were also calculated and used in the statistical analysis. The statistical analysis has allowed us to hypothesize the importance of these radial distances and the polar angles of key atoms in the chalcones in binding to the pyruvate kinase crystal structure. This was validated by the docking of another small library of compound models in which the α,β-unsaturated ketone chain of the chalcone was replaced by incrementally longer conjugated chains. Further studies on the chalcones themselves reveal rotameric systems in both cis and trans-configurations (which may impact binding), and also studied was the effect of Topliss-based modification and its impact of binding to HSP90. Molecular dynamics confirmed good binding of identified chalcone hits.
- Full Text:
- Date Issued: 2020
- Authors: Sarron, Arthur F D
- Date: 2020
- Subjects: Acetophenone , Benzaldehyde , Ketones , Pyruvate kinase , Drug development , Aromatic compounds , Heat shock proteins
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/116028 , vital:34291
- Description: Chalcone family molecules are well known to have therapeutic proprieties (anti-inflammatory, anti-microbial or anti-cancer, etc). However the mechanism of action in some cases is not well known. A virtual library of this family of compounds was constructed using custom scripts, based on the aldol condensation, and this library was modified further to analogues by expansion of the α,β-unsaturated ketone linker. Acetophenone and benzaldehyde derivatives which are available and purchasable were used as a base to design the chalcone virtual library. 8063 chalcones were constructed and geometrically optimized with Gaussian 09. Their physicochemical characteristics linked to the Lipinski rules were analyzed with Knime and CDK. The entire library was after docked against several targets including HIV-1 integrase, MRSA pyruvate kinase, HSP90, COX-1, COX-2, ALR2, MAOA, MAOB, acetylcholinesterase, butyrylcholinesterase and PLA2. With the exception of MAOA, which does not have a crystal structure ligand, all dockings were validated by redocking the original ligand provided by the literature. These targets are known in the literature to be inhibited by chalcone-derivatives. However, specificity of the particular known chalcone inhibitors to the particular targets is not known. To this end the performance of the generated chalcone library against the list of targets was of interest. The binding energy of ligand-protein complexes was generally good across the library. Statistical analysis including principal component analysis and hierarchical clustering analysis were made in order to investigate for any physical/chemical characteristics which might explain what chalcone features affect the binding energy of the ligand-protein complexes. The spherical polar coordinates defining the orientation of the binding poses were also calculated and used in the statistical analysis. The statistical analysis has allowed us to hypothesize the importance of these radial distances and the polar angles of key atoms in the chalcones in binding to the pyruvate kinase crystal structure. This was validated by the docking of another small library of compound models in which the α,β-unsaturated ketone chain of the chalcone was replaced by incrementally longer conjugated chains. Further studies on the chalcones themselves reveal rotameric systems in both cis and trans-configurations (which may impact binding), and also studied was the effect of Topliss-based modification and its impact of binding to HSP90. Molecular dynamics confirmed good binding of identified chalcone hits.
- Full Text:
- Date Issued: 2020
Adaptive Neuro-Fuzzy Inference System modelling of surface topology in ultra-high precision diamond turning of rapidly solidified aluminium grade (RSA 443)
- Authors: Zvikomborero, Hweju
- Date: 2020
- Subjects: Mechatronics Surface roughness -- Measurement
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/49441 , vital:41721
- Description: Surface roughness prediction is a crucial stage during product manufacturing since it acts as a quality indicator. This investigative research thesis presents an online surface roughness prediction, based on the Adaptive Neuro-Fuzzy Inference System (ANFIS) model during Ultra-High Precision Diamond Turning (UHPDT) of Rapidly Solidified Aluminium (RSA-443) using water and kerosene as coolants. Based on the Taguchi L9 orthogonal array, the cutting parameters (spindle speed, depth of cut and feed rate) are varied at three levels. Acoustic Emission (AE) signals are detected during the UHPDT process using a piezoelectric sensor. Spindle speed, depth of cut, feed rate, AE root mean square, prominent frequency and peak rate are considered as model inputs in this thesis. The experimental results reveal that a better surface finish is obtained using water coolant in comparison to kerosene coolant. Mean Absolute Percentage Error (MAPE) based comparison between ANFIS and Response Surface Method (RSM) is carried out. In this study, the ANFIS model has a prediction accuracy of 79.42% and 69.40% on water-based and kerosene-based results respectively. The RSM model yields higher prediction accuracies of 98.59% and 95.55% on water-based and kerosene-based results respectively.
- Full Text:
- Date Issued: 2020
- Authors: Zvikomborero, Hweju
- Date: 2020
- Subjects: Mechatronics Surface roughness -- Measurement
- Language: English
- Type: Thesis , Masters , MEng
- Identifier: http://hdl.handle.net/10948/49441 , vital:41721
- Description: Surface roughness prediction is a crucial stage during product manufacturing since it acts as a quality indicator. This investigative research thesis presents an online surface roughness prediction, based on the Adaptive Neuro-Fuzzy Inference System (ANFIS) model during Ultra-High Precision Diamond Turning (UHPDT) of Rapidly Solidified Aluminium (RSA-443) using water and kerosene as coolants. Based on the Taguchi L9 orthogonal array, the cutting parameters (spindle speed, depth of cut and feed rate) are varied at three levels. Acoustic Emission (AE) signals are detected during the UHPDT process using a piezoelectric sensor. Spindle speed, depth of cut, feed rate, AE root mean square, prominent frequency and peak rate are considered as model inputs in this thesis. The experimental results reveal that a better surface finish is obtained using water coolant in comparison to kerosene coolant. Mean Absolute Percentage Error (MAPE) based comparison between ANFIS and Response Surface Method (RSM) is carried out. In this study, the ANFIS model has a prediction accuracy of 79.42% and 69.40% on water-based and kerosene-based results respectively. The RSM model yields higher prediction accuracies of 98.59% and 95.55% on water-based and kerosene-based results respectively.
- Full Text:
- Date Issued: 2020
Addo Elephant National Park 1900 – 1955: An Environmental History of the struggle between elephants and emerging commercial farmers in the Sundays River Valley
- Jones,Nicholas Austen Inskip
- Authors: Jones,Nicholas Austen Inskip
- Date: 2020
- Subjects: Wildlife conservation -- South Africa -- Addo National Park
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/46922 , vital:39733
- Description: The research covers the first half of the 20th Century in the Sundays River Valley, and the relations between the elephants and the local farmers. The research includes some discussion of the implementation of new ideas to agriculture, irrigation, and colonial settlement with the interplay between the colonial farmers and the Administration. There is reference to the early politics surrounding nature conservation and the difficulties faced by farmers from wildlife and the difficulty wildlife face trying to co-exist alongside early intensive commercial agriculture.Included is the decision making process of the Colonial administration with reference to wildlife and agriculture relating to charismatic animal species.
- Full Text:
- Date Issued: 2020
- Authors: Jones,Nicholas Austen Inskip
- Date: 2020
- Subjects: Wildlife conservation -- South Africa -- Addo National Park
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/46922 , vital:39733
- Description: The research covers the first half of the 20th Century in the Sundays River Valley, and the relations between the elephants and the local farmers. The research includes some discussion of the implementation of new ideas to agriculture, irrigation, and colonial settlement with the interplay between the colonial farmers and the Administration. There is reference to the early politics surrounding nature conservation and the difficulties faced by farmers from wildlife and the difficulty wildlife face trying to co-exist alongside early intensive commercial agriculture.Included is the decision making process of the Colonial administration with reference to wildlife and agriculture relating to charismatic animal species.
- Full Text:
- Date Issued: 2020
Addressing flux suppression, radio frequency interference, and selection of optimal solution intervals during radio interferometric calibration
- Authors: Sob, Ulrich Armel Mbou
- Date: 2020
- Subjects: CubiCal (Software) , Radio -- Interference , Imaging systems in astronomy , Algorithms , Astronomical instruments -- Calibration , Astronomy -- Data processing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/147714 , vital:38663
- Description: The forthcoming Square Kilometre Array is expected to provide answers to some of the most intriguing questions about our Universe. However, as it is already noticeable from MeerKAT and other precursors, the amounts of data produced by these new instruments are significantly challenging to calibrate and image. Calibration of radio interferometric data is usually biased by incomplete sky models and radio frequency interference (RFI) resulting in calibration artefacts that limit the dynamic range and image fidelity of the resulting images. One of the most noticeable of these artefacts is the formation of spurious sources which causes suppression of real emissions. Fortunately, it has been shown that calibration algorithms employing heavy-tailed likelihood functions are less susceptible to this due to their robustness against outliers. Leveraging on recent developments in the field of complex optimisation, we implement a robust calibration algorithm using a Student’s t likelihood function and Wirtinger derivatives. The new algorithm, dubbed the robust solver, is incorporated as a subroutine into the newly released calibration software package CubiCal. We perform statistical analysis on the distribution of visibilities and provide an insight into the functioning of the robust solver and describe different scenarios where it will improve calibration. We use simulations to show that the robust solver effectively reduces the amount of flux suppressed from unmodelled sources both in direction independent and direction dependent calibration. Furthermore, the robust solver is shown to successfully mitigate the effects of low-level RFI when applied to a simulated and a real VLA dataset. Finally, we demonstrate that there are close links between the amount of flux suppressed from sources, the effects of the RFI and the employed solution interval during radio interferometric calibration. Hence, we investigate the effects of solution intervals and the different factors to consider in order to select adequate solution intervals. Furthermore, we propose a practical brute force method for selecting optimal solution intervals. The proposed method is successfully applied to a VLA dataset.
- Full Text:
- Date Issued: 2020
- Authors: Sob, Ulrich Armel Mbou
- Date: 2020
- Subjects: CubiCal (Software) , Radio -- Interference , Imaging systems in astronomy , Algorithms , Astronomical instruments -- Calibration , Astronomy -- Data processing
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/147714 , vital:38663
- Description: The forthcoming Square Kilometre Array is expected to provide answers to some of the most intriguing questions about our Universe. However, as it is already noticeable from MeerKAT and other precursors, the amounts of data produced by these new instruments are significantly challenging to calibrate and image. Calibration of radio interferometric data is usually biased by incomplete sky models and radio frequency interference (RFI) resulting in calibration artefacts that limit the dynamic range and image fidelity of the resulting images. One of the most noticeable of these artefacts is the formation of spurious sources which causes suppression of real emissions. Fortunately, it has been shown that calibration algorithms employing heavy-tailed likelihood functions are less susceptible to this due to their robustness against outliers. Leveraging on recent developments in the field of complex optimisation, we implement a robust calibration algorithm using a Student’s t likelihood function and Wirtinger derivatives. The new algorithm, dubbed the robust solver, is incorporated as a subroutine into the newly released calibration software package CubiCal. We perform statistical analysis on the distribution of visibilities and provide an insight into the functioning of the robust solver and describe different scenarios where it will improve calibration. We use simulations to show that the robust solver effectively reduces the amount of flux suppressed from unmodelled sources both in direction independent and direction dependent calibration. Furthermore, the robust solver is shown to successfully mitigate the effects of low-level RFI when applied to a simulated and a real VLA dataset. Finally, we demonstrate that there are close links between the amount of flux suppressed from sources, the effects of the RFI and the employed solution interval during radio interferometric calibration. Hence, we investigate the effects of solution intervals and the different factors to consider in order to select adequate solution intervals. Furthermore, we propose a practical brute force method for selecting optimal solution intervals. The proposed method is successfully applied to a VLA dataset.
- Full Text:
- Date Issued: 2020