Calibration and wide field imaging with PAPER: a catalogue of compact sources
- Authors: Philip, Liju
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2397 , vital:20285
- Description: Observations of the redshifted 21 cm HI line promise to be a formidable tool for cosmology, allowing the investigation of the end of the so-called dark ages, when the first galaxies formed, and the subsequent Epoch of Reionization when the intergalactic medium transitioned from neutral to ionized. Such observations are plagued by foreground emission which is a few orders of magnitude brighter than the 21 cm line. In this thesis I analyzed data from the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER) in order to improve the characterization of the extragalactic foreground component. I derived a catalogue of unresolved radio sources down to a 5 Jy flux density limit at 150 MHz and derived their spectral index distribution using literature data at 408 MHz. I implemented advanced techniques to calibrate radio interferometric data that led to a few percent accuracy on the flux density scale of the derived catalogue. This work, therefore, represents a further step towards creating an accurate, global sky model that is crucial to improve calibration of Epoch of Reionization observations.
- Full Text:
- Authors: Philip, Liju
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2397 , vital:20285
- Description: Observations of the redshifted 21 cm HI line promise to be a formidable tool for cosmology, allowing the investigation of the end of the so-called dark ages, when the first galaxies formed, and the subsequent Epoch of Reionization when the intergalactic medium transitioned from neutral to ionized. Such observations are plagued by foreground emission which is a few orders of magnitude brighter than the 21 cm line. In this thesis I analyzed data from the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER) in order to improve the characterization of the extragalactic foreground component. I derived a catalogue of unresolved radio sources down to a 5 Jy flux density limit at 150 MHz and derived their spectral index distribution using literature data at 408 MHz. I implemented advanced techniques to calibrate radio interferometric data that led to a few percent accuracy on the flux density scale of the derived catalogue. This work, therefore, represents a further step towards creating an accurate, global sky model that is crucial to improve calibration of Epoch of Reionization observations.
- Full Text:
Changing planets and climates in select fantastic literature
- Authors: Ward, Brendan
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3994 , vital:20578
- Description: This thesis is concerned with literature’s engagement with the environment, specifically ecosystems and climate change. Literature of the fantastic, works that break from the tradition of mimetic literature and the limits of realism, are the focus of this thesis, which argues, alongside ecocriticism, that literature must be part of the interdisciplinary drive towards greater ecological awareness. Speculative literature adds fantastic elements or draws on scientific extrapolations into the future, and offers a platform to engage with the science of environmental issues alongside philosophical engagements with the relationship between humans and the more-than-human world around them. This thesis draws on ecocriticism to examine the role of reading and criticism in constructing more ecologically sustainable societies. From this position, it asks how fantasy can be used to convey these themes. As a result, this thesis is interested in definitions of fantasy, drawing on science fiction and fantasy to examine Kathryn Hume’s framework of the fantastic impulse. Placing fantastic texts on two axes, Hume examines the ways texts support or subvert the reader’s expectations, and encourage or discourage reflection on their extratextual worlds. This thesis contends that, texts that encourage engagement are most transformative, but that the spectrum of engagement and disengagement challenges authors to navigate between didacticism and emotive imagery. To show this, this thesis examines four series of novels drawing on the fantastic impulse. Frank Herbert’s Dune Chronicles, Kim Stanley Robinson’s Mars Trilogy and Science in the Capital, and George R.R. Martin’s A Song of Ice and Fire. The first two are on opposite ends of both of Hume’s axes, and imagine the challenges of constructing Earth-like ecosystems on other planets, asking questions about the sustainability of such a project as well as the possibilities of transforming society. The latter two engage with rapid climate change, Robinson’s looking at contemporary climate change and Martin’s engaging with historical climate change. They interrogate the impact of the climate on human and more- than-human life, and reveal the tension between comforting didactic revisions of human- environment interactions and framework-disturbing alternate ways of relating to the environment. This tension is where the fantastic is powerful, allowing alternate visions to pierce sceptical readers’ defences.
- Full Text:
- Authors: Ward, Brendan
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3994 , vital:20578
- Description: This thesis is concerned with literature’s engagement with the environment, specifically ecosystems and climate change. Literature of the fantastic, works that break from the tradition of mimetic literature and the limits of realism, are the focus of this thesis, which argues, alongside ecocriticism, that literature must be part of the interdisciplinary drive towards greater ecological awareness. Speculative literature adds fantastic elements or draws on scientific extrapolations into the future, and offers a platform to engage with the science of environmental issues alongside philosophical engagements with the relationship between humans and the more-than-human world around them. This thesis draws on ecocriticism to examine the role of reading and criticism in constructing more ecologically sustainable societies. From this position, it asks how fantasy can be used to convey these themes. As a result, this thesis is interested in definitions of fantasy, drawing on science fiction and fantasy to examine Kathryn Hume’s framework of the fantastic impulse. Placing fantastic texts on two axes, Hume examines the ways texts support or subvert the reader’s expectations, and encourage or discourage reflection on their extratextual worlds. This thesis contends that, texts that encourage engagement are most transformative, but that the spectrum of engagement and disengagement challenges authors to navigate between didacticism and emotive imagery. To show this, this thesis examines four series of novels drawing on the fantastic impulse. Frank Herbert’s Dune Chronicles, Kim Stanley Robinson’s Mars Trilogy and Science in the Capital, and George R.R. Martin’s A Song of Ice and Fire. The first two are on opposite ends of both of Hume’s axes, and imagine the challenges of constructing Earth-like ecosystems on other planets, asking questions about the sustainability of such a project as well as the possibilities of transforming society. The latter two engage with rapid climate change, Robinson’s looking at contemporary climate change and Martin’s engaging with historical climate change. They interrogate the impact of the climate on human and more- than-human life, and reveal the tension between comforting didactic revisions of human- environment interactions and framework-disturbing alternate ways of relating to the environment. This tension is where the fantastic is powerful, allowing alternate visions to pierce sceptical readers’ defences.
- Full Text:
Class actions as a means of enhancing access to justice in South Africa
- Authors: Marumo, Tladi
- Date: 2016
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3723 , http://hdl.handle.net/10962/d1021267
- Description: 21 years into democracy South Africa is marked by starkly contrasting experiences in the lives of its citizens. For some few, theirs remains a society defined by opulence and social, economic and political entitlements that accompany it. For a few beneficiaries, democracy has brought with it remarkable changes which have translated through their lives in economic, political and socialempowerment and wellbeing. Accompanying these changes has been the establishment and importantly, the enhancement of access to modern political and legal democratic and participatoryinstitutions of governance for these citizens. And yet, for the remaining majority of South Africans, their experience is marked by social and economic deprivation, poverty and vulnerability. These latter experiences are attributable to the historical legacy of colonialism and apartheid which continues to present itself in the form of persistent poverty and inequality in a ‘new South Africa.’ It is within this new South Africa, that this deprivation is further exacerbated by an increasingly unaccountable and unresponsive government ‘at war with its citizens.’ Service delivery protests, then have become a (if not the) way in which the poor and vulnerable get together as a collective, to try and take on the government in way they know how within their means, on deprivations of housing, electricity, water, sanitation, social assistance, healthcare and education. Finding an alternative legal means, whereby poor and vulnerable people themselves, may address these challenges is in the purpose of this thesis. However, the emphasis is not on addressing the plight of vulnerable groups through dependency from outside help, but on finding a means in which the agency (albeit constrained) of people to address their own concerns is recognised. The work investigates how law can enhance the collective agency of poor people to change their socioeconomic circumstances. In particular I investigate how the class action, a legal device which can enable people to come together collectively as a class in litigation for the enforcement of their rights of access to housing, electricity, water, sanitation, social assistance, healthcare and education, can achieve this. I provide recommendations on legal reform on how best access to courts can be made easier through the removal of barriers for impoverished communities to collectively enforce their socio-economic rights. I position the Regulation of Gatherings Act, a legislation which is aimed at affording legal protection to protest action, as a as accessible gateway into towards class litigation.
- Full Text:
- Authors: Marumo, Tladi
- Date: 2016
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3723 , http://hdl.handle.net/10962/d1021267
- Description: 21 years into democracy South Africa is marked by starkly contrasting experiences in the lives of its citizens. For some few, theirs remains a society defined by opulence and social, economic and political entitlements that accompany it. For a few beneficiaries, democracy has brought with it remarkable changes which have translated through their lives in economic, political and socialempowerment and wellbeing. Accompanying these changes has been the establishment and importantly, the enhancement of access to modern political and legal democratic and participatoryinstitutions of governance for these citizens. And yet, for the remaining majority of South Africans, their experience is marked by social and economic deprivation, poverty and vulnerability. These latter experiences are attributable to the historical legacy of colonialism and apartheid which continues to present itself in the form of persistent poverty and inequality in a ‘new South Africa.’ It is within this new South Africa, that this deprivation is further exacerbated by an increasingly unaccountable and unresponsive government ‘at war with its citizens.’ Service delivery protests, then have become a (if not the) way in which the poor and vulnerable get together as a collective, to try and take on the government in way they know how within their means, on deprivations of housing, electricity, water, sanitation, social assistance, healthcare and education. Finding an alternative legal means, whereby poor and vulnerable people themselves, may address these challenges is in the purpose of this thesis. However, the emphasis is not on addressing the plight of vulnerable groups through dependency from outside help, but on finding a means in which the agency (albeit constrained) of people to address their own concerns is recognised. The work investigates how law can enhance the collective agency of poor people to change their socioeconomic circumstances. In particular I investigate how the class action, a legal device which can enable people to come together collectively as a class in litigation for the enforcement of their rights of access to housing, electricity, water, sanitation, social assistance, healthcare and education, can achieve this. I provide recommendations on legal reform on how best access to courts can be made easier through the removal of barriers for impoverished communities to collectively enforce their socio-economic rights. I position the Regulation of Gatherings Act, a legislation which is aimed at affording legal protection to protest action, as a as accessible gateway into towards class litigation.
- Full Text:
Classical and quantum picture of the interior of two-dimensional black holes
- Authors: Shawa, Mark
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3629 , vital:20531
- Description: A quantum-mechanical description of black holes would represent the final step in our understanding of the nature of space-time. However, any progress towards that end is usually foiled by persistent space-time singularities that exist at the center of black holes. From the four-dimensional point of view, black holes seem to resist quantization. Under highly symmetric conditions, all higher-dimensional black holes are two-dimensional. Unlike their higher-dimensional counterparts, two dimensional black holes may not resist quantization. A non-trivial description of gravity in two dimensions is not possible using Einstein’s theory of gravity alone. However, we may still arrive at a consistent description of gravity by introducing a scalar field known as the dilaton. In this thesis, we study both the classical and quantum aspects of the interior of two-dimensional black holes using a generalized dilaton-gravity theory. Classically, we will find that the interior of most two-dimensional black holes is not much different from that of four-dimensional black holes. But by introducing quantized matter into the theory, the fluctuations in space-time will give a different picture of the structure of interior of black holes. Using a low-energy effective field theory, we will show that it is indeed possible to identify quantum modes in the interior of black holes and perform quantum-mechanical calculations near the singularity.
- Full Text:
- Authors: Shawa, Mark
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/3629 , vital:20531
- Description: A quantum-mechanical description of black holes would represent the final step in our understanding of the nature of space-time. However, any progress towards that end is usually foiled by persistent space-time singularities that exist at the center of black holes. From the four-dimensional point of view, black holes seem to resist quantization. Under highly symmetric conditions, all higher-dimensional black holes are two-dimensional. Unlike their higher-dimensional counterparts, two dimensional black holes may not resist quantization. A non-trivial description of gravity in two dimensions is not possible using Einstein’s theory of gravity alone. However, we may still arrive at a consistent description of gravity by introducing a scalar field known as the dilaton. In this thesis, we study both the classical and quantum aspects of the interior of two-dimensional black holes using a generalized dilaton-gravity theory. Classically, we will find that the interior of most two-dimensional black holes is not much different from that of four-dimensional black holes. But by introducing quantized matter into the theory, the fluctuations in space-time will give a different picture of the structure of interior of black holes. Using a low-energy effective field theory, we will show that it is indeed possible to identify quantum modes in the interior of black holes and perform quantum-mechanical calculations near the singularity.
- Full Text:
Codeswitching online: a case study of a bilingual online maths programme for grade 7 learners in Diepsloot, Johannesburg
- Authors: von Witt, Nathalia
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3983 , vital:20577
- Description: There is an education crisis in South Africa. Mathematics and literacy are at the forefront of the problem, as particularly evidenced by Annual National Assessment results (Department of Basic Education, 2014; Spaull, 2014). This research is motivated by the unequal access to quality learning which stems from learners learning through a poorly-understood second language with little to no cognitive academic language proficiency. The vast majority of South African learners learn through their second language, English, from Grade 4 onwards. English is the language of South Africa’s political economy and is a global lingua franca; however, the understanding of concepts and content learnt at school is vital if one is to have any hope of putting one’s English to good use. This research aimed to find a way to equip learners both with English proficiency and mathematical understanding simultaneously. This was done by implementing and evaluating an experimental bilingual course in an existing mathematics programme in the township of Diepsloot in Johannesburg, South Africa. This research used design-based research methodology, using both qualitative and quantitative research methods. This methodology was chosen as it allows theory and practice to intersect in a real-life setting, and for the successes and shortcomings of this intersection to be evaluated. This study encompasses both the evaluation and creation of the bilingual online mathematics course. The course is made bilingual through the creation of bilingual videos with the use of translanguaging and the creation of a bilingual glossary of terms. The videos were created using a translanguaging ‘model’ informed by theories of basic interpersonal communication skills and cognitive academic language proficiency (Cummins, 1981), common underlying proficiency (Cummins, 1991), codeswitching (Setati, 1998; Ncoko et al., 2000) and translanguaging (Makalela 2015; Creese and Blackledge, 2010a). The aim of this research was to create a successful translanguaging model which facilitates learners’ ability to conceptualise in their first language and then discuss and understand the concept in their second language.
- Full Text:
- Authors: von Witt, Nathalia
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3983 , vital:20577
- Description: There is an education crisis in South Africa. Mathematics and literacy are at the forefront of the problem, as particularly evidenced by Annual National Assessment results (Department of Basic Education, 2014; Spaull, 2014). This research is motivated by the unequal access to quality learning which stems from learners learning through a poorly-understood second language with little to no cognitive academic language proficiency. The vast majority of South African learners learn through their second language, English, from Grade 4 onwards. English is the language of South Africa’s political economy and is a global lingua franca; however, the understanding of concepts and content learnt at school is vital if one is to have any hope of putting one’s English to good use. This research aimed to find a way to equip learners both with English proficiency and mathematical understanding simultaneously. This was done by implementing and evaluating an experimental bilingual course in an existing mathematics programme in the township of Diepsloot in Johannesburg, South Africa. This research used design-based research methodology, using both qualitative and quantitative research methods. This methodology was chosen as it allows theory and practice to intersect in a real-life setting, and for the successes and shortcomings of this intersection to be evaluated. This study encompasses both the evaluation and creation of the bilingual online mathematics course. The course is made bilingual through the creation of bilingual videos with the use of translanguaging and the creation of a bilingual glossary of terms. The videos were created using a translanguaging ‘model’ informed by theories of basic interpersonal communication skills and cognitive academic language proficiency (Cummins, 1981), common underlying proficiency (Cummins, 1991), codeswitching (Setati, 1998; Ncoko et al., 2000) and translanguaging (Makalela 2015; Creese and Blackledge, 2010a). The aim of this research was to create a successful translanguaging model which facilitates learners’ ability to conceptualise in their first language and then discuss and understand the concept in their second language.
- Full Text:
Community care workers in TB care: identifying and meeting their information needs
- Authors: Okeyo, Ida L A
- Date: 2016
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/4211 , vital:20633
- Description: According to the 2015 World Health Organisation global tuberculosis report, South Africa had 155,473 new TB cases in the last year, 61% of whom were HIV-positive. The tuberculosis (TB) epidemic in South Africa has resulted in the increasing use of community care workers (CCWs) for the management and supervision of TB patients on treatment. CCWs are increasingly being deployed to address the shortages of healthcare workers. CCWs supervising TB patients often act as information providers, advising and counselling patients on general care and medication use. Their effectiveness depends on appropriate knowledge, adequate training and access to good quality information about TB and TB medicines. The hypothesis for this study was that user-friendly, simple, illustrated information can enhance TB knowledge of CCWs, as well as serve as a practice tool in facilitating their counselling and education of patients. A conceptual framework was used to guide the development of an intervention to test this hypothesis through the following objectives: exploring the roles and TB information needs of CCWs working with TB patients; evaluating baseline TB knowledge and health literacy levels of CCWs; developing simple, illustrated information materials to address CCW TB information needs; and assessing the influence of the information materials on TB knowledge and practice of CCWs. Six CCWs from Grahamstown Hospice and 25 CCWs from six primary healthcare clinics in Grahamstown participated in the study, which was conducted in three main phases. Phase 1 began with focus group discussions and individual semi-structured interviews with 14 CCWs to explore their perceptions regarding their roles in TB care and their information needs. This was followed by individual interviews with all 31 CCWs using a structured questionnaire to collect quantitative data on health literacy and establish baseline TB knowledge. For Phase 2, the design of an A5 booklet was informed by the findings from Phase 1 and contained information about TB and TB medication. Pictograms were designed using a rigorous, iterative design process and were included in the booklet which was translated into isiXhosa and Afrikaans. The booklets were individually distributed to CCWs during an information session in which the topics in the booklet were discussed. Three months after completion of Phase 2, individual follow-up interviews were conducted with all CCWs to measure post-intervention TB knowledge. Focus group discussions or semi-structured interviews were conducted with 19 of the CCWs to explore the role and impact of the information materials on everyday CCW practice. Qualitative data were transcribed and analysed thematically by developing codes and identifying themes. Quantitative results were analysed using the t-test, Pearson Chi-square and a Z-test of proportions at a 0.05 level of significance. The conceptual framework provided a useful lens through which to view, and reflect on, the interaction between the elements of the healthcare system in relation to the results obtained. CCWs associated their roles in TB control with helping patients and having an impact in patients’ lives which they perceived as being meaningful. The good relationships with patients noted by study CCWs, as well as the appreciation they received from patients, contributed to their confidence and belief that they were well positioned and able to positively influence health outcomes. This study found that CCWs in the healthcare system were disadvantaged by the lack of support and supervision, deficiencies in training and lack of information materials, all of which reflect a negative interaction between CCWs with the healthcare system. Use of the booklet resulted in an improvement in CCW knowledge about the disease, TB medication, MDR and XDR-TB and HIV/AIDS and TB co-infection. The mean knowledge score significantly increased from 76.1% at baseline to 85.4% at follow up showing that the use of the booklet had a positive impact on TB knowledge. Poor knowledge areas were identified as being related to TB medication-related knowledge and drug-resistant TB, highlighting the need for additional intervention to improve knowledge in these areas. The health literacy level of CCWs, which was assessed using the modified Newest Vital Signs– South Africa test, showed that the majority of CCWs had only marginal health literacy, indicating the need for wider assessment of health literacy within CCWs, and the need to tailor training and information materials to cater for their health literacy levels. The pictorial-based, simple booklet tailored for CCWs was also found to enhance confidence in decision making, and reduce their uncertainty when confronted with difficult care scenarios. CCWs were enthusiastic about the inclusion of pictograms which were reported to enhance recall of TB information and understanding of text. The booklet also served as a patient educational tool, where it reportedly improved communication and had a positive effect on the CCW-patient interpersonal relationship. The simplicity of the booklet and the inclusion of pictograms resulted in a user-friendly appealing information source for patients. Factors contributing to the success of the booklet can be attributed to paying attention to CCW information needs, involving CCWs in the design process, translating the booklet into local dialect, ensuring simplicity of the text and including pictograms that had undergone a rigorous design process. This study was the first to design TB information materials targeted specifically for CCWs that were also suitable as patient education materials. The study demonstrated that these information materials can have a positive outcome on CCW roles in TB care by improving their knowledge and facilitating patient communication and education.
- Full Text:
- Authors: Okeyo, Ida L A
- Date: 2016
- Language: English
- Type: Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/4211 , vital:20633
- Description: According to the 2015 World Health Organisation global tuberculosis report, South Africa had 155,473 new TB cases in the last year, 61% of whom were HIV-positive. The tuberculosis (TB) epidemic in South Africa has resulted in the increasing use of community care workers (CCWs) for the management and supervision of TB patients on treatment. CCWs are increasingly being deployed to address the shortages of healthcare workers. CCWs supervising TB patients often act as information providers, advising and counselling patients on general care and medication use. Their effectiveness depends on appropriate knowledge, adequate training and access to good quality information about TB and TB medicines. The hypothesis for this study was that user-friendly, simple, illustrated information can enhance TB knowledge of CCWs, as well as serve as a practice tool in facilitating their counselling and education of patients. A conceptual framework was used to guide the development of an intervention to test this hypothesis through the following objectives: exploring the roles and TB information needs of CCWs working with TB patients; evaluating baseline TB knowledge and health literacy levels of CCWs; developing simple, illustrated information materials to address CCW TB information needs; and assessing the influence of the information materials on TB knowledge and practice of CCWs. Six CCWs from Grahamstown Hospice and 25 CCWs from six primary healthcare clinics in Grahamstown participated in the study, which was conducted in three main phases. Phase 1 began with focus group discussions and individual semi-structured interviews with 14 CCWs to explore their perceptions regarding their roles in TB care and their information needs. This was followed by individual interviews with all 31 CCWs using a structured questionnaire to collect quantitative data on health literacy and establish baseline TB knowledge. For Phase 2, the design of an A5 booklet was informed by the findings from Phase 1 and contained information about TB and TB medication. Pictograms were designed using a rigorous, iterative design process and were included in the booklet which was translated into isiXhosa and Afrikaans. The booklets were individually distributed to CCWs during an information session in which the topics in the booklet were discussed. Three months after completion of Phase 2, individual follow-up interviews were conducted with all CCWs to measure post-intervention TB knowledge. Focus group discussions or semi-structured interviews were conducted with 19 of the CCWs to explore the role and impact of the information materials on everyday CCW practice. Qualitative data were transcribed and analysed thematically by developing codes and identifying themes. Quantitative results were analysed using the t-test, Pearson Chi-square and a Z-test of proportions at a 0.05 level of significance. The conceptual framework provided a useful lens through which to view, and reflect on, the interaction between the elements of the healthcare system in relation to the results obtained. CCWs associated their roles in TB control with helping patients and having an impact in patients’ lives which they perceived as being meaningful. The good relationships with patients noted by study CCWs, as well as the appreciation they received from patients, contributed to their confidence and belief that they were well positioned and able to positively influence health outcomes. This study found that CCWs in the healthcare system were disadvantaged by the lack of support and supervision, deficiencies in training and lack of information materials, all of which reflect a negative interaction between CCWs with the healthcare system. Use of the booklet resulted in an improvement in CCW knowledge about the disease, TB medication, MDR and XDR-TB and HIV/AIDS and TB co-infection. The mean knowledge score significantly increased from 76.1% at baseline to 85.4% at follow up showing that the use of the booklet had a positive impact on TB knowledge. Poor knowledge areas were identified as being related to TB medication-related knowledge and drug-resistant TB, highlighting the need for additional intervention to improve knowledge in these areas. The health literacy level of CCWs, which was assessed using the modified Newest Vital Signs– South Africa test, showed that the majority of CCWs had only marginal health literacy, indicating the need for wider assessment of health literacy within CCWs, and the need to tailor training and information materials to cater for their health literacy levels. The pictorial-based, simple booklet tailored for CCWs was also found to enhance confidence in decision making, and reduce their uncertainty when confronted with difficult care scenarios. CCWs were enthusiastic about the inclusion of pictograms which were reported to enhance recall of TB information and understanding of text. The booklet also served as a patient educational tool, where it reportedly improved communication and had a positive effect on the CCW-patient interpersonal relationship. The simplicity of the booklet and the inclusion of pictograms resulted in a user-friendly appealing information source for patients. Factors contributing to the success of the booklet can be attributed to paying attention to CCW information needs, involving CCWs in the design process, translating the booklet into local dialect, ensuring simplicity of the text and including pictograms that had undergone a rigorous design process. This study was the first to design TB information materials targeted specifically for CCWs that were also suitable as patient education materials. The study demonstrated that these information materials can have a positive outcome on CCW roles in TB care by improving their knowledge and facilitating patient communication and education.
- Full Text:
Community structure and trophic ecology of shallow and deep rocky reefs in a well-established marine protected area
- Authors: Heyns, Elodie R
- Date: 2016
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54438 , vital:26565
- Description: The now formally adopted ecosystem approach to fisheries (EAF) considers not only commercially important species, but the entire ecosystem and the processes that support these species. A key component of EAF management is the implementation of no-take Marine Protected Areas (MPAs). Shallow water fish stocks are depleted and fishing effort is moving deeper and further offshore to keep up with demands. This situation calls for a detailed investigation of deep nearshore reefs to provide critical information relevant to policy uptake and management decisions regarding existing and new MPAs in terms of zonation and use. To address this need, the aim of this thesis was to investigate reefs that lie between 45 and 75 m and compare them in terms of community structure and function to the relatively well-studied shallow reefs that lie within SCUBA diving depth (<25 m). Ecological collections were made in the centre of a large and well-established MPA, Tsitsikamma National Park, to ensure that data represented non-anthropogenically impacted communities. Data were collected from two study sites; Rheeders Reef, (shallow reef) and Middlebank, a deep reef complex situated near the Storms River Mouth. The first step to address the aim of this study was to obtain baseline data on the distribution patterns of both the macrobenthic invertebrates and fish assemblages. Baseline data were obtained by underwater video methods and included the use of a remotely operated vehicle, baited remote underwater stereo-video systems (stereo-BRUVs) and traditional underwater camera equipment operated by SCUBA divers. To establish functional differences between the two study sites, fatty acid (FA) and stable isotope (SI) analyses were employed. These biomarker techniques provided insight into the importance of different sources of primary production, nutritional condition and species packing. From 360 photoquadrats examined for macrobenthic invertebrate distribution patterns, 161 invertebrates were identified that demonstrated a clear changeover of species along the depth gradient. Species richness was highest on the shallow reef and decreased with an increase in depth. To understand how the measured environmental variables impacted the macrobenthic assemblage data a LINKTREE analysis was performed. LINKTREEs produce hierarchical cluster analysis based on the macrobenthic assemblage data and provide a threshold of environmental variables that correspond to each cluster. The outcome of the LINKTREE analysis indicated that the changeover of species resulted in four distinct clusters, each cluster associated with a particular set of environmental variables that fell within a depth range. On the shallowest sites, the high energy environment resulting from wave action and surge prevented the settlement of suspended particles. The high energy environment of the shallow reef selected for low-growing encrusting species. High light intensities supported great abundances of benthic algae, and as light was lost with increasing depth, algal cover gradually diminished until it was completely absent on the deep reef. The reduced impact of surface wave action on the deep reef caused increased levels of settled suspended particles. The high levels of settled particles likely caused clogging of feeding parts of the encrusting species. Consequently, upright growth forms were more common in the lower energy environment of the deep reef. A total of 48 fish species were identified from 51 stereo-BRUVs samples. Fish assemblages differed significantly between the shallow and deep reefs. The shallowest sites were characterised by many small and juvenile fish species that fed at lower trophic levels. The deep reef supported the majority of the large predatory fish that fed at higher trophic levels. Many species demonstrated depth-related ontogenetic shifts in habitat use, and as such the deep reef hosted the majority of the sexually mature individuals. The fish assemblages also demonstrated a strong association with the macrobenthic clusters identified as habitat types by the LINKTREE analysis. The results from 201 FA and 191 SI samples provided information on specific feeding interactions, but more importantly shed some light on different processes that supported the shallow and deep reef communities. The shallow reef community was characterised by greater diversity of food sources, a pattern that could be explained by the presence of benthic algae and terrestrial inputs. Greater diversity of carbon sources at the bottom of the food web meant that a larger variety of species could be supported. Higher species richness increased the number of distinct taxa that performed similar functions, rendering the shallow reef more redundant and consequently more resilient to disturbance. In contrast, the deep reef demonstrated a food web supported mainly by pelagic production, which was more variable both over space and time. The deep reef was less redundant when compared to the shallow reef, as fewer species demonstrated similar trophic niches. These factors, in addition to the increased presence of sensitive calcareous macrobenthic species on the deep study site, rendered the deep reef more vulnerable to disturbance when compared to the shallow reef. Although the data presented here were from a single study area, the limitations typically associated with these inaccessible and challenging sampling environments made the dataset a significant contribution to the knowledge of reef ecosystems. The study addressed priority research questions for South Africa as identified during the National Biodiversity Assessment. The observable differences in structure, function and vulnerability point to the need for continued protection of our shallow reefs and offshore expansion of our MPA networks. Future research should determine if the patterns identified here are common throughout the Agulhas Ecoregion to provide managers with robust evidence for the extension our MPAs offshore.
- Full Text:
- Authors: Heyns, Elodie R
- Date: 2016
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54438 , vital:26565
- Description: The now formally adopted ecosystem approach to fisheries (EAF) considers not only commercially important species, but the entire ecosystem and the processes that support these species. A key component of EAF management is the implementation of no-take Marine Protected Areas (MPAs). Shallow water fish stocks are depleted and fishing effort is moving deeper and further offshore to keep up with demands. This situation calls for a detailed investigation of deep nearshore reefs to provide critical information relevant to policy uptake and management decisions regarding existing and new MPAs in terms of zonation and use. To address this need, the aim of this thesis was to investigate reefs that lie between 45 and 75 m and compare them in terms of community structure and function to the relatively well-studied shallow reefs that lie within SCUBA diving depth (<25 m). Ecological collections were made in the centre of a large and well-established MPA, Tsitsikamma National Park, to ensure that data represented non-anthropogenically impacted communities. Data were collected from two study sites; Rheeders Reef, (shallow reef) and Middlebank, a deep reef complex situated near the Storms River Mouth. The first step to address the aim of this study was to obtain baseline data on the distribution patterns of both the macrobenthic invertebrates and fish assemblages. Baseline data were obtained by underwater video methods and included the use of a remotely operated vehicle, baited remote underwater stereo-video systems (stereo-BRUVs) and traditional underwater camera equipment operated by SCUBA divers. To establish functional differences between the two study sites, fatty acid (FA) and stable isotope (SI) analyses were employed. These biomarker techniques provided insight into the importance of different sources of primary production, nutritional condition and species packing. From 360 photoquadrats examined for macrobenthic invertebrate distribution patterns, 161 invertebrates were identified that demonstrated a clear changeover of species along the depth gradient. Species richness was highest on the shallow reef and decreased with an increase in depth. To understand how the measured environmental variables impacted the macrobenthic assemblage data a LINKTREE analysis was performed. LINKTREEs produce hierarchical cluster analysis based on the macrobenthic assemblage data and provide a threshold of environmental variables that correspond to each cluster. The outcome of the LINKTREE analysis indicated that the changeover of species resulted in four distinct clusters, each cluster associated with a particular set of environmental variables that fell within a depth range. On the shallowest sites, the high energy environment resulting from wave action and surge prevented the settlement of suspended particles. The high energy environment of the shallow reef selected for low-growing encrusting species. High light intensities supported great abundances of benthic algae, and as light was lost with increasing depth, algal cover gradually diminished until it was completely absent on the deep reef. The reduced impact of surface wave action on the deep reef caused increased levels of settled suspended particles. The high levels of settled particles likely caused clogging of feeding parts of the encrusting species. Consequently, upright growth forms were more common in the lower energy environment of the deep reef. A total of 48 fish species were identified from 51 stereo-BRUVs samples. Fish assemblages differed significantly between the shallow and deep reefs. The shallowest sites were characterised by many small and juvenile fish species that fed at lower trophic levels. The deep reef supported the majority of the large predatory fish that fed at higher trophic levels. Many species demonstrated depth-related ontogenetic shifts in habitat use, and as such the deep reef hosted the majority of the sexually mature individuals. The fish assemblages also demonstrated a strong association with the macrobenthic clusters identified as habitat types by the LINKTREE analysis. The results from 201 FA and 191 SI samples provided information on specific feeding interactions, but more importantly shed some light on different processes that supported the shallow and deep reef communities. The shallow reef community was characterised by greater diversity of food sources, a pattern that could be explained by the presence of benthic algae and terrestrial inputs. Greater diversity of carbon sources at the bottom of the food web meant that a larger variety of species could be supported. Higher species richness increased the number of distinct taxa that performed similar functions, rendering the shallow reef more redundant and consequently more resilient to disturbance. In contrast, the deep reef demonstrated a food web supported mainly by pelagic production, which was more variable both over space and time. The deep reef was less redundant when compared to the shallow reef, as fewer species demonstrated similar trophic niches. These factors, in addition to the increased presence of sensitive calcareous macrobenthic species on the deep study site, rendered the deep reef more vulnerable to disturbance when compared to the shallow reef. Although the data presented here were from a single study area, the limitations typically associated with these inaccessible and challenging sampling environments made the dataset a significant contribution to the knowledge of reef ecosystems. The study addressed priority research questions for South Africa as identified during the National Biodiversity Assessment. The observable differences in structure, function and vulnerability point to the need for continued protection of our shallow reefs and offshore expansion of our MPA networks. Future research should determine if the patterns identified here are common throughout the Agulhas Ecoregion to provide managers with robust evidence for the extension our MPAs offshore.
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Comparative analysis of existing pipelines for assessment of arbuscular mycorrhizal fungal biodiversity in natural and commercial rooibos (aspalathus linearis) and honeybush (cyclopia intermedia) soil samples
- Authors: De Wit, Hermina Johanna
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2915 , vital:20342
- Full Text:
- Authors: De Wit, Hermina Johanna
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2915 , vital:20342
- Full Text:
Composing affect: reflection on configurations of body, sound and technology in contemporary South African performance
- Authors: Cilliers, Ilana
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3377 , vital:20478
- Description: This thesis engages with experiential performance modes through the lenses of phenomenology and affect theory. Because experiential performance relies per definition on personal, subjective ‘experience’, specific responses cannot be anticipated. However, by attempting to compose ‘affect’, a performance has the potential to ‘move’ an attendant towards response. Deleuze and Guattari define ‘affect’ as “an ability to affect and be affected….a prepersonal intensity corresponding to the passage from one experiential state of the body to another and implying an augmentation or diminution in that body’s capacity to act” (1987: xvi). One current strategy for manifesting affect in performance seems to be the ways in which different configurations of body, sound and technology are employed. The body is the means through which sound is received or ‘experienced’ in the phenomenological sense, but it can also act as a source for sonic material. The body is furthermore the means by which sonic technology is manipulated. It is the complex, reverberating relationships between body, sound and technology, and their potential for eliciting affective transformation, which is the focus of my enquiry. In the first chapter I unpack the roles of the natural phenomena, body and sound, and their complex relationships to affect. The chapter serves as philosophical basis for the rest of the investigation, and draws largely on works by philosophers Susan Kozel, Maurice Merleau-Ponty, Brian Massumi, Gille Deleuze and Félix Guatarri and sound theorists Don Ihde, Marshall McLuhan, Brandon LaBelle and Frances Dyson.In the remaining three chapters I discuss current South African theatre works that employ the strategy of placing emphasis on sound, sonic technology, and its relationship to the human body. These works are my own piece herTz (2014), Jaco Bouwer’s pieces Samsa-masjien (2014) and Na-aap (2013), and First Physical Theatre Company’s Everyday Falling (2010). While they range from being plays to physical theatre performances to performative experiments, they all place specific emphasis on sonic devices, drawing attention to sound by revealing microphones, speakers, midi boards, etc. to the attendants, and including the generation and manipulation of sound in the action of the performance.
- Full Text:
- Authors: Cilliers, Ilana
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3377 , vital:20478
- Description: This thesis engages with experiential performance modes through the lenses of phenomenology and affect theory. Because experiential performance relies per definition on personal, subjective ‘experience’, specific responses cannot be anticipated. However, by attempting to compose ‘affect’, a performance has the potential to ‘move’ an attendant towards response. Deleuze and Guattari define ‘affect’ as “an ability to affect and be affected….a prepersonal intensity corresponding to the passage from one experiential state of the body to another and implying an augmentation or diminution in that body’s capacity to act” (1987: xvi). One current strategy for manifesting affect in performance seems to be the ways in which different configurations of body, sound and technology are employed. The body is the means through which sound is received or ‘experienced’ in the phenomenological sense, but it can also act as a source for sonic material. The body is furthermore the means by which sonic technology is manipulated. It is the complex, reverberating relationships between body, sound and technology, and their potential for eliciting affective transformation, which is the focus of my enquiry. In the first chapter I unpack the roles of the natural phenomena, body and sound, and their complex relationships to affect. The chapter serves as philosophical basis for the rest of the investigation, and draws largely on works by philosophers Susan Kozel, Maurice Merleau-Ponty, Brian Massumi, Gille Deleuze and Félix Guatarri and sound theorists Don Ihde, Marshall McLuhan, Brandon LaBelle and Frances Dyson.In the remaining three chapters I discuss current South African theatre works that employ the strategy of placing emphasis on sound, sonic technology, and its relationship to the human body. These works are my own piece herTz (2014), Jaco Bouwer’s pieces Samsa-masjien (2014) and Na-aap (2013), and First Physical Theatre Company’s Everyday Falling (2010). While they range from being plays to physical theatre performances to performative experiments, they all place specific emphasis on sonic devices, drawing attention to sound by revealing microphones, speakers, midi boards, etc. to the attendants, and including the generation and manipulation of sound in the action of the performance.
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Constructing a local approach to journalism education: a study of Zambian educators’ conceptualisation of the ideal journalism curriculum
- Authors: Milupi, Mulako
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3552 , http://hdl.handle.net/10962/d1021228
- Description: This research is an investigation of Zambian journalism educators’ conception of the knowledge, competencies and values that should inform their teaching practice. The study establishes how such educators conceptualise of the purpose of journalism education within the Zambian context. As part of this examination, it identifies characteristics of this context that educators regard to be of relevance to their conceptualisation of such purpose. It then identifies what they understand as the implications for the design of the ideal journalism education curriculum. The study assesses the relevance of these perspectives to the teaching of journalism in Zambia, as an example of an African country with a ‘developing’ economy. The study draws for its theoretical framework on journalism studies generally and scholarship about journalism education more specifically. It is argued that a review of the global history of journalism education points to the existence of three main traditions of teaching that have developed internationally. The first of these traditions is described as being dedicated to the project of ‘professionalisation’; the second to the production of ‘critical practitioners’, and the third to the project of ‘social development’. These traditions are based on different understandings with regard to the principles on which journalism education programmes should be based and the kind of knowledge that they should draw on. It is noted that this body of literature does not include extensive research of the way in which particular groups of African journalism educators respond to these traditions. In order to contribute to such research, the empirical component of this study sets out to explore Zambian journalism educators’ conceptualisation of journalism education within their own social context. It does so by means of an exploration of journalism educators based, respectively, at the Evelyn Hone College of Applied Arts (EHC) and the University of Zambia (UNZA)’s Mass Communication Department. The foremost conclusion of the research is that both the professionalising and developmental tradition can be observed to influence the participants’ discussion.
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- Authors: Milupi, Mulako
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3552 , http://hdl.handle.net/10962/d1021228
- Description: This research is an investigation of Zambian journalism educators’ conception of the knowledge, competencies and values that should inform their teaching practice. The study establishes how such educators conceptualise of the purpose of journalism education within the Zambian context. As part of this examination, it identifies characteristics of this context that educators regard to be of relevance to their conceptualisation of such purpose. It then identifies what they understand as the implications for the design of the ideal journalism education curriculum. The study assesses the relevance of these perspectives to the teaching of journalism in Zambia, as an example of an African country with a ‘developing’ economy. The study draws for its theoretical framework on journalism studies generally and scholarship about journalism education more specifically. It is argued that a review of the global history of journalism education points to the existence of three main traditions of teaching that have developed internationally. The first of these traditions is described as being dedicated to the project of ‘professionalisation’; the second to the production of ‘critical practitioners’, and the third to the project of ‘social development’. These traditions are based on different understandings with regard to the principles on which journalism education programmes should be based and the kind of knowledge that they should draw on. It is noted that this body of literature does not include extensive research of the way in which particular groups of African journalism educators respond to these traditions. In order to contribute to such research, the empirical component of this study sets out to explore Zambian journalism educators’ conceptualisation of journalism education within their own social context. It does so by means of an exploration of journalism educators based, respectively, at the Evelyn Hone College of Applied Arts (EHC) and the University of Zambia (UNZA)’s Mass Communication Department. The foremost conclusion of the research is that both the professionalising and developmental tradition can be observed to influence the participants’ discussion.
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Contesting masculinities: a study of selected texts of resistance to conscription into the South African Defence Force (SADF) in the 1980s
- Authors: Mason, Paul
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2332 , http://hdl.handle.net/10962/d1020842
- Description: The theoretical framework for this thesis and analysis of primary texts revolves around the problem of conscription into the South African Defence Force (SADF) in the 1980s. The ideology of masculinity that underpinned and sustained the practice of conscription is referred to throughout as the hegemonic version. This term is interchangeable with others, namely masculinism and ‗the real man.‘ The aim is to interpret the selected texts for strains of resistance to the practice of conscription and its assumptions as to what to what constitutes the natural or real man. In the Introduction to this thesis I begin by explaining the personal dimension of my role as researcher, after which I motivate my research project and explain its theoretical and methodological orientation, focusing on the concepts that play a significant role in analysis of the primary texts. The Introduction concludes with an outline of the content of Chapters 1–5. Chapter 1 begins with a brief discussion, on the general level, of the practice of conscription and resistance to it, and proceeds to a concern with conscription in 1980s South Africa. Attention is paid to prevailing attitudes towards gender and sexuality within both the SADF and the End Conscription Campaign (ECC). Discussion of gender and sexuality as constructs of identity proceeds to a focus on the conceptual tools for textual analysis provided by theories of masculinity. The final section of this chapter pays attention to specific post-structuralist notions of identity that serve analysis of the primary texts, that is, the notions of the subject, agency and the author. Having engaged mainly with secondary texts in Chapter 1, Chapter 2 presents the first sustained critical engagement with primary texts in which resistance was expressed against the institution of conscription and the hegemonic version of masculinity that underpinned it. These expressions of resistance occurred within a rock music counter-culture of the period, known as the Voëlvry movement. Attention is given to overlaps or links between this counter-culture and that of America in the 1960s, as well echoes between the Vietnam and Border Wars. Analysis of these links is applied to a memoir selected for its appropriateness. Threaded through the chapter is a concern with expressions of masculine identity within the Voëlvry counter-culture, the SADF and the ECC. Chapter 3 focuses on three novels and one collection of short stories, each narrated in the first person and written by gay authors who performed their National Service. Attention is paid to the protagonists‘ perceptions of themselves, their troubled relationships with their fathers, and the struggle to come out within a context that prohibited them from doing so. Chapter 4 concerns three wartime memoirs and two written by men who refused to perform their National Service. Underlying concerns in this chapter are the question of fact versus fiction in the genre of the memoir, authors‘ perceptions of and relationships with women, and expressions of vulnerability. Chapter 5 concentrates on the interviews that comprise the Appendix. The chapter establishes its theoretical ground by focusing on principles of narrative structure and the relation of personal to narrative identity. The chapter pays attention to the displays of power and the vulnerabilities of both veteran soldiers and resisters. Theory deployed in analysis of the primary texts serves the principal concerns articulated in the title to the thesis.
- Full Text:
- Authors: Mason, Paul
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2332 , http://hdl.handle.net/10962/d1020842
- Description: The theoretical framework for this thesis and analysis of primary texts revolves around the problem of conscription into the South African Defence Force (SADF) in the 1980s. The ideology of masculinity that underpinned and sustained the practice of conscription is referred to throughout as the hegemonic version. This term is interchangeable with others, namely masculinism and ‗the real man.‘ The aim is to interpret the selected texts for strains of resistance to the practice of conscription and its assumptions as to what to what constitutes the natural or real man. In the Introduction to this thesis I begin by explaining the personal dimension of my role as researcher, after which I motivate my research project and explain its theoretical and methodological orientation, focusing on the concepts that play a significant role in analysis of the primary texts. The Introduction concludes with an outline of the content of Chapters 1–5. Chapter 1 begins with a brief discussion, on the general level, of the practice of conscription and resistance to it, and proceeds to a concern with conscription in 1980s South Africa. Attention is paid to prevailing attitudes towards gender and sexuality within both the SADF and the End Conscription Campaign (ECC). Discussion of gender and sexuality as constructs of identity proceeds to a focus on the conceptual tools for textual analysis provided by theories of masculinity. The final section of this chapter pays attention to specific post-structuralist notions of identity that serve analysis of the primary texts, that is, the notions of the subject, agency and the author. Having engaged mainly with secondary texts in Chapter 1, Chapter 2 presents the first sustained critical engagement with primary texts in which resistance was expressed against the institution of conscription and the hegemonic version of masculinity that underpinned it. These expressions of resistance occurred within a rock music counter-culture of the period, known as the Voëlvry movement. Attention is given to overlaps or links between this counter-culture and that of America in the 1960s, as well echoes between the Vietnam and Border Wars. Analysis of these links is applied to a memoir selected for its appropriateness. Threaded through the chapter is a concern with expressions of masculine identity within the Voëlvry counter-culture, the SADF and the ECC. Chapter 3 focuses on three novels and one collection of short stories, each narrated in the first person and written by gay authors who performed their National Service. Attention is paid to the protagonists‘ perceptions of themselves, their troubled relationships with their fathers, and the struggle to come out within a context that prohibited them from doing so. Chapter 4 concerns three wartime memoirs and two written by men who refused to perform their National Service. Underlying concerns in this chapter are the question of fact versus fiction in the genre of the memoir, authors‘ perceptions of and relationships with women, and expressions of vulnerability. Chapter 5 concentrates on the interviews that comprise the Appendix. The chapter establishes its theoretical ground by focusing on principles of narrative structure and the relation of personal to narrative identity. The chapter pays attention to the displays of power and the vulnerabilities of both veteran soldiers and resisters. Theory deployed in analysis of the primary texts serves the principal concerns articulated in the title to the thesis.
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Controls on the distribution of manganese in banded iron-formations (BIF) of the palaeoproterozoic transvaal supergroup, South Africa
- Authors: Fryer, Lindi
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2926 , vital:20343
- Description: The 2.65 to 2.05 Ga Transvaal Supergroup comprises one of the best-preserved and largely continuous successions in the world of Banded Iron-Formation (BIF), a chemical sedimentary rock composed of fine (mm to cm scale) interbanded iron-rich and iron-poor bands, developed atop the Archaean Kaapvaal Craton of southern Africa. The Transvaal BIF sequence contains at its upper stratigraphic part, an intriguing interlayered BIF-Mn association, namely the Hotazel Formation in the Kalahari Manganese Field, which constitutes the largest land-based manganese deposit on record. The genesis of the Hotazel deposits, and their exact significance in terms of atmosphere-hydrosphere-biosphere evolution, remain as elusive as they are challenging. In this thesis, an attempt is made to illuminate the origin and diagenesis of the Hotazel Formation and its post-depositional hydrothermal modification, through a highresolution geochemical study of the narrowest of the three BIF-Mn sedimentary cycles present in the Hotazel stratigraphy. This approach is coupled with a preliminary geochemical study of the distribution of Mn in older BIF of the Transvaal Supergroup as well (Kuruman and Griquatown Formations), so as to test recent models that causally link all BIFs in the Transvaal Supergroup under a common and evolving palaeo-environment of deposition. The results indicate that the cyclic deposition of the Hotazel BIF and enveloped Mn-rich sediments would have taken place in a stratified basin with a well-developed chemocline in terms of the vertical distributions of Mn and Fe, much like recent anoxic stratified basins such as the Orca Basin in the Gulf of Mexico. The increased Mn abundances as Mn-bearing ferrous carbonates in the upper part of the Griquatown BIF predating the Hotazel strata, also seems to lend support to the notion that the two BIFs are temporally interlinked as part of a broader sedimentary continuum. Finally, the largely conservative behaviour of Mn and associated elements during hydrothermal alteration of the Hotazel rocks is re-assessed, and renewed emphasis is placed on the possibility that brine metasomatism may have been a key factor in Mn redistribution and residual enrichment.
- Full Text:
- Authors: Fryer, Lindi
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2926 , vital:20343
- Description: The 2.65 to 2.05 Ga Transvaal Supergroup comprises one of the best-preserved and largely continuous successions in the world of Banded Iron-Formation (BIF), a chemical sedimentary rock composed of fine (mm to cm scale) interbanded iron-rich and iron-poor bands, developed atop the Archaean Kaapvaal Craton of southern Africa. The Transvaal BIF sequence contains at its upper stratigraphic part, an intriguing interlayered BIF-Mn association, namely the Hotazel Formation in the Kalahari Manganese Field, which constitutes the largest land-based manganese deposit on record. The genesis of the Hotazel deposits, and their exact significance in terms of atmosphere-hydrosphere-biosphere evolution, remain as elusive as they are challenging. In this thesis, an attempt is made to illuminate the origin and diagenesis of the Hotazel Formation and its post-depositional hydrothermal modification, through a highresolution geochemical study of the narrowest of the three BIF-Mn sedimentary cycles present in the Hotazel stratigraphy. This approach is coupled with a preliminary geochemical study of the distribution of Mn in older BIF of the Transvaal Supergroup as well (Kuruman and Griquatown Formations), so as to test recent models that causally link all BIFs in the Transvaal Supergroup under a common and evolving palaeo-environment of deposition. The results indicate that the cyclic deposition of the Hotazel BIF and enveloped Mn-rich sediments would have taken place in a stratified basin with a well-developed chemocline in terms of the vertical distributions of Mn and Fe, much like recent anoxic stratified basins such as the Orca Basin in the Gulf of Mexico. The increased Mn abundances as Mn-bearing ferrous carbonates in the upper part of the Griquatown BIF predating the Hotazel strata, also seems to lend support to the notion that the two BIFs are temporally interlinked as part of a broader sedimentary continuum. Finally, the largely conservative behaviour of Mn and associated elements during hydrothermal alteration of the Hotazel rocks is re-assessed, and renewed emphasis is placed on the possibility that brine metasomatism may have been a key factor in Mn redistribution and residual enrichment.
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Cosmological structure formation using spectral methods
- Authors: Funcke, Michelle
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2969 , vital:20348
- Description: Numerical simulations are becoming an increasingly important tool for understanding the growth and development of structure in the universe. Common practice is to discretize the space-time using physical variables. The discreteness is embodied by considering the dynamical variables as fields on a fixed spatial and time resolution, or by constructing the matter fields by a large number of particles which interact gravitationally (N-body methods). Recognizing that the physical quantities of interest are related to the spectrum of perturbations, we propose an alternate discretization in the frequency domain, using standard spectral methods. This approach is further aided by periodic boundary conditions which allows a straightforward decomposition of variables in a Fourier basis. Fixed resources require a high-frequency cut-off which lead to aliasing effects in non-linear equations, such as the ones considered here. This thesis describes the implementation of a 3D cosmological model based on Newtonian hydrodynamic equations in an expanding background. Initial data is constructed as a spectrum of perturbations, and evolved in the frequency domain using a pseudo-spectral evolution scheme and an explicit Runge-Kutta time integrator. The code is found to converge for both linear and non-linear evolutions, and the convergence rate is determined. The correct growth rates expected from analytical calculations are recovered in the linear case. In the non-linear model, we observe close correspondence with linear growth and are able to monitor the growth on features associated with the non-linearity. High-frequency aliasing effects were evident in the non-linear evolutions, leading to a study of two potential resolutions to this problem: a boxcar filter which adheres to“Orszag’s two thirds rule” and an exponential window function, the exponential filter suggested by Hou and Li [1], and a shifted version of the exponential filter suggested, which has the potential to alleviate high frequency- ripples resulting from the Gibbs’ phenomenon. We found that the filters were somewhat successful at reducing aliasing effects but that the Gibbs’ phenomenon could not be entirely removed by the choice of filters.
- Full Text:
- Authors: Funcke, Michelle
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2969 , vital:20348
- Description: Numerical simulations are becoming an increasingly important tool for understanding the growth and development of structure in the universe. Common practice is to discretize the space-time using physical variables. The discreteness is embodied by considering the dynamical variables as fields on a fixed spatial and time resolution, or by constructing the matter fields by a large number of particles which interact gravitationally (N-body methods). Recognizing that the physical quantities of interest are related to the spectrum of perturbations, we propose an alternate discretization in the frequency domain, using standard spectral methods. This approach is further aided by periodic boundary conditions which allows a straightforward decomposition of variables in a Fourier basis. Fixed resources require a high-frequency cut-off which lead to aliasing effects in non-linear equations, such as the ones considered here. This thesis describes the implementation of a 3D cosmological model based on Newtonian hydrodynamic equations in an expanding background. Initial data is constructed as a spectrum of perturbations, and evolved in the frequency domain using a pseudo-spectral evolution scheme and an explicit Runge-Kutta time integrator. The code is found to converge for both linear and non-linear evolutions, and the convergence rate is determined. The correct growth rates expected from analytical calculations are recovered in the linear case. In the non-linear model, we observe close correspondence with linear growth and are able to monitor the growth on features associated with the non-linearity. High-frequency aliasing effects were evident in the non-linear evolutions, leading to a study of two potential resolutions to this problem: a boxcar filter which adheres to“Orszag’s two thirds rule” and an exponential window function, the exponential filter suggested by Hou and Li [1], and a shifted version of the exponential filter suggested, which has the potential to alleviate high frequency- ripples resulting from the Gibbs’ phenomenon. We found that the filters were somewhat successful at reducing aliasing effects but that the Gibbs’ phenomenon could not be entirely removed by the choice of filters.
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Creating evidence-based guidelines for healthy eating educational campaigns aimed at low-income South Africans: a case study of Grahamstown
- Authors: Booth, Christopher
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3336 , vital:20485
- Description: Through a literature review and qualitative research, this study explores what a media-centric nutritional intervention needs to include in order to be effective amongst those whose health is most impacted by poor nutrition – poorer and mostly black South Africans. The study sketches the current nutritional landscape of South Africa, and draws on both Behaviour Change Communication and Media Effect theories to hypothesise how a campaign might be devised to change popular understandings of the relationship between health and nutrition, and inspire some change in food consumption behaviours and choices. The study explores the key factors that drive nutritional behaviours (including the environmental constraint of cost, the peer pressure and socialisation of food, and the desire for knowledge and change) and explores how media-based interventions could be more effective. To do this, this study creates three layers of an idealised and hypothetical “Super 7” fruit and vegetable consumption promotion campaign. From this data, and the insights developed, new guidelines for possible future nutritional education campaigns are suggested and developed.
- Full Text:
- Authors: Booth, Christopher
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10962/3336 , vital:20485
- Description: Through a literature review and qualitative research, this study explores what a media-centric nutritional intervention needs to include in order to be effective amongst those whose health is most impacted by poor nutrition – poorer and mostly black South Africans. The study sketches the current nutritional landscape of South Africa, and draws on both Behaviour Change Communication and Media Effect theories to hypothesise how a campaign might be devised to change popular understandings of the relationship between health and nutrition, and inspire some change in food consumption behaviours and choices. The study explores the key factors that drive nutritional behaviours (including the environmental constraint of cost, the peer pressure and socialisation of food, and the desire for knowledge and change) and explores how media-based interventions could be more effective. To do this, this study creates three layers of an idealised and hypothetical “Super 7” fruit and vegetable consumption promotion campaign. From this data, and the insights developed, new guidelines for possible future nutritional education campaigns are suggested and developed.
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Detecting derivative malware samples using deobfuscation-assisted similarity analysis
- Authors: Wrench, Peter Mark
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/383 , vital:19954
- Description: The overwhelming popularity of PHP as a hosting platform has made it the language of choice for developers of Remote Access Trojans (RATs or web shells) and other malicious software. These shells are typically used to compromise and monetise web platforms by providing the attacker with basic remote access to the system, including _le transfer, command execution, network reconnaissance, and database connectivity. Once infected, compromised systems can be used to defraud users by hosting phishing sites, performing Distributed Denial of Service attacks, or serving as anonymous platforms for sending spam or other malfeasance. The vast majority of these threats are largely derivative, incorporating core capabilities found in more established RATs such as c99 and r57. Authors of malicious software routinely produce new shell variants by modifying the behaviours of these ubiquitous RATs, either to add desired functionality or to avoid detection by signature-based detection systems. Once these modified shells are eventually identified (or additional functionality is required), the process of shell adaptation begins again. The end result of this iterative process is a web of separate but related shell variants, many of which are at least partially derived from one of the more popular and influential RATs. In response to the problem outlined above, the author set out to design and implement a system capable of circumventing common obfuscation techniques and identifying derivative malware samples in a given collection. To begin with, a decoder component was developed to syntactically deobfuscate and normalise PHP code by detecting and reversing idiomatic obfuscation constructs, and to apply uniform formatting conventions to all system inputs. A unified malware analysis framework, called Viper, was then extended to create a modular similarity analysis system comprised of individual feature extraction modules, modules responsible for batch processing, a matrix module for comparing sample features, and two visualisation modules capable of generating visual representations of shell similarity. The principal conclusion of the research was that the deobfuscation performed by the decoder component prior to analysis dramatically improved the observed levels of similarity between test samples. This in turn allowed the modular similarity analysis system to identify derivative clusters (or families) within a large collection of shells more accurately. Techniques for isolating and re-rendering these clusters were also developed and demonstrated to be effective at increasing the amount of detail available for evaluating the relative magnitudes of the relationships within each cluster.
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- Authors: Wrench, Peter Mark
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/383 , vital:19954
- Description: The overwhelming popularity of PHP as a hosting platform has made it the language of choice for developers of Remote Access Trojans (RATs or web shells) and other malicious software. These shells are typically used to compromise and monetise web platforms by providing the attacker with basic remote access to the system, including _le transfer, command execution, network reconnaissance, and database connectivity. Once infected, compromised systems can be used to defraud users by hosting phishing sites, performing Distributed Denial of Service attacks, or serving as anonymous platforms for sending spam or other malfeasance. The vast majority of these threats are largely derivative, incorporating core capabilities found in more established RATs such as c99 and r57. Authors of malicious software routinely produce new shell variants by modifying the behaviours of these ubiquitous RATs, either to add desired functionality or to avoid detection by signature-based detection systems. Once these modified shells are eventually identified (or additional functionality is required), the process of shell adaptation begins again. The end result of this iterative process is a web of separate but related shell variants, many of which are at least partially derived from one of the more popular and influential RATs. In response to the problem outlined above, the author set out to design and implement a system capable of circumventing common obfuscation techniques and identifying derivative malware samples in a given collection. To begin with, a decoder component was developed to syntactically deobfuscate and normalise PHP code by detecting and reversing idiomatic obfuscation constructs, and to apply uniform formatting conventions to all system inputs. A unified malware analysis framework, called Viper, was then extended to create a modular similarity analysis system comprised of individual feature extraction modules, modules responsible for batch processing, a matrix module for comparing sample features, and two visualisation modules capable of generating visual representations of shell similarity. The principal conclusion of the research was that the deobfuscation performed by the decoder component prior to analysis dramatically improved the observed levels of similarity between test samples. This in turn allowed the modular similarity analysis system to identify derivative clusters (or families) within a large collection of shells more accurately. Techniques for isolating and re-rendering these clusters were also developed and demonstrated to be effective at increasing the amount of detail available for evaluating the relative magnitudes of the relationships within each cluster.
- Full Text:
Developing a lean and green manufacturing plan for the newspaper printing industry - considering the Rising Sun Printers
- Authors: Maharaj, Avish
- Date: 2016
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:867 , http://hdl.handle.net/10962/d1021249
- Description: This research is focused on lean and green manufacturing using a printing company in South Africa as a case study focusing on their printing division. The reason for addressing the printing division of the company was to develop a lean and green manufacturing plan to address the concerns of resource utilisation and waste disposal in the printing division. The research looked at the concept of lean and green individually as well as together and by analysing the relationship between the two concepts. The outcome was that environmental “green” waste is embedded in the seven types of lean waste which is overproduction, waiting, transport, inappropriate processing, unnecessary inventory, unnecessary motion and waste due to defects (Moreira, Alves and Sousa, 2010 cited in Pampanelli, Found and Bernardes, 2014). It was found that the company under consideration had not been familiar with these concepts but learnt and understood the value it could bring to the company. The research concludes with the plan using the 5S tool to reduce the seven types of waste linked to lean and green manufacturing.
- Full Text:
- Authors: Maharaj, Avish
- Date: 2016
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:867 , http://hdl.handle.net/10962/d1021249
- Description: This research is focused on lean and green manufacturing using a printing company in South Africa as a case study focusing on their printing division. The reason for addressing the printing division of the company was to develop a lean and green manufacturing plan to address the concerns of resource utilisation and waste disposal in the printing division. The research looked at the concept of lean and green individually as well as together and by analysing the relationship between the two concepts. The outcome was that environmental “green” waste is embedded in the seven types of lean waste which is overproduction, waiting, transport, inappropriate processing, unnecessary inventory, unnecessary motion and waste due to defects (Moreira, Alves and Sousa, 2010 cited in Pampanelli, Found and Bernardes, 2014). It was found that the company under consideration had not been familiar with these concepts but learnt and understood the value it could bring to the company. The research concludes with the plan using the 5S tool to reduce the seven types of waste linked to lean and green manufacturing.
- Full Text:
Developing an attractant for monitoring fruit-feeding moths in citrus orchards
- Authors: Goddard, Mathew Keith
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2981 , vital:20349
- Description: Fruit-piercing moths are a sporadic pest of citrus, especially in the Eastern Cape Province of South Africa, where the adults can cause significant damage in outbreak years. Currently the only way in which to successfully control fruit-feeding moths within the orchards is the use of repellent lights. However, growers confuse fruit-piercing moths with fruit-sucking moths that don‘t cause primary damage, and there is no way of monitoring which moth species are attacking the fruit in the orchards during the night. In a previous study, banana was shown to be the most attractive bait for a variety of fruit-feeding moth species. Therefore the aim of this study was to determine the population dynamics of fruit-feeding moths develop a cost-effective alternative to the use of fresh banana as a bait for fruit-piercing moths. Fresh banana was compared to nine alternative synthetic attractants, frozen banana and a control under field conditions in several orchards in the Eastern Cape Province. Once again, banana was shown to be the most attractive bait. Some 23 species of fruit-feeding moth species were sampled in the traps, but there was only two fruit-piercing species, Serrodes partita (Fabricius) (Lepidoptera: Noctuidae) and Eudocima sp. Surprisingly S. partita, which was thought to be the main pest, comprised only 6.9% of trap catches. Serrodes partita, is a sporadic pest, only becoming problematic every five to 10 years after good rainfall in the Little Karoo region that causes flushes of their larval host, wild plum, Pappea capensis (Ecklon and Zeyher). During these outbreaks, damage to fruit can range from 70 to 90% and this is especially so for soft skinned citrus. A study on the morphology of the proboscis confirmed that only two species of fruit-piercing moths were present. Trap catches over three citrus growing seasons was linked to fruit damage found within several orchards. Once again fruit-piercing moth damage was relatively low in comparison to other types of damage such as mechanical and undefined damage. There was a very weak correlation between S. partita trap catches and damage, but generally damage was recorded two to three weeks after a peak in S. partita trap catches. Climatic conditions were also recorded and compared to weekly trap catches of S. partita, and while temperature and wind direction had no influence on moth populations, precipitation in the orchards was weakly correlated with trap catches. This study has shown that in non-outbreak seasons, the main fruit-piercing moth, S. partita comprises a small percentage of fruit-feeding moths in citrus orchards, but that growers are unable to determine the difference between fruit-piercing species and the harmless fruit-sucking species. Further fresh banana remains the best method for attracting fruit-piecing moths to traps, but this is not cost effective and thus a commercially viable protocol for monitoring these species remains elusive.
- Full Text:
- Authors: Goddard, Mathew Keith
- Date: 2016
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/2981 , vital:20349
- Description: Fruit-piercing moths are a sporadic pest of citrus, especially in the Eastern Cape Province of South Africa, where the adults can cause significant damage in outbreak years. Currently the only way in which to successfully control fruit-feeding moths within the orchards is the use of repellent lights. However, growers confuse fruit-piercing moths with fruit-sucking moths that don‘t cause primary damage, and there is no way of monitoring which moth species are attacking the fruit in the orchards during the night. In a previous study, banana was shown to be the most attractive bait for a variety of fruit-feeding moth species. Therefore the aim of this study was to determine the population dynamics of fruit-feeding moths develop a cost-effective alternative to the use of fresh banana as a bait for fruit-piercing moths. Fresh banana was compared to nine alternative synthetic attractants, frozen banana and a control under field conditions in several orchards in the Eastern Cape Province. Once again, banana was shown to be the most attractive bait. Some 23 species of fruit-feeding moth species were sampled in the traps, but there was only two fruit-piercing species, Serrodes partita (Fabricius) (Lepidoptera: Noctuidae) and Eudocima sp. Surprisingly S. partita, which was thought to be the main pest, comprised only 6.9% of trap catches. Serrodes partita, is a sporadic pest, only becoming problematic every five to 10 years after good rainfall in the Little Karoo region that causes flushes of their larval host, wild plum, Pappea capensis (Ecklon and Zeyher). During these outbreaks, damage to fruit can range from 70 to 90% and this is especially so for soft skinned citrus. A study on the morphology of the proboscis confirmed that only two species of fruit-piercing moths were present. Trap catches over three citrus growing seasons was linked to fruit damage found within several orchards. Once again fruit-piercing moth damage was relatively low in comparison to other types of damage such as mechanical and undefined damage. There was a very weak correlation between S. partita trap catches and damage, but generally damage was recorded two to three weeks after a peak in S. partita trap catches. Climatic conditions were also recorded and compared to weekly trap catches of S. partita, and while temperature and wind direction had no influence on moth populations, precipitation in the orchards was weakly correlated with trap catches. This study has shown that in non-outbreak seasons, the main fruit-piercing moth, S. partita comprises a small percentage of fruit-feeding moths in citrus orchards, but that growers are unable to determine the difference between fruit-piercing species and the harmless fruit-sucking species. Further fresh banana remains the best method for attracting fruit-piecing moths to traps, but this is not cost effective and thus a commercially viable protocol for monitoring these species remains elusive.
- Full Text:
Development of a high-throughput bioassay to determine the rate of antimalarial drug action using fluorescent vitality probes
- Authors: Laming, Dustin
- Date: 2016
- Subjects: Malaria -- Africa , Plasmodium falciparum , Drug development , Fluorescence
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/64434 , vital:28542
- Description: Malaria is one of the most prevalent diseases in Africa and the Plasmodium falciparum species is widely accepted as the most virulent, with a fatality rate of 15 – 20 % of reported cases of infection. While various treatments have been accepted into early stage clinical trials there has been little progress towards a proven vaccine. Pending a long term solution, endemic countries rely heavily on the development of innovative drugs with acute efficacy coupled with rapids mode of action. Until recently the rate of drug action has been measured by light microscopic examination of parasite morphology using blood slides of drug treated parasite cultures at regular time intervals. This technique is tedious and, most importantly, subject to interpretation with regards to distinguishing between viable and comprised parasite cells, thus making it impossible to objectively quantitate the rate of drug action. This study aimed to develop a series of bioassays using the calcein-acetoxymethyl and propidium iodide vitality probes which would allow the rate of drug action on Plasmodium falciparum malaria parasites to be assessed and ranked in relation to each other. A novel bioassay using these fluorescent vitality probes coupled with fluorescence microscopy was developed and optimized and allowed the rate of drug action on malaria parasites to be assessed i) rapidly (in relation to current assay techniques) and ii) in a semi-quantitative manner. Extrapolation to flow cytometry for improved quantification provided favourable rankings of drug killing rates in the pilot study, however, requires further development to increase throughput and approach the ultimate goal of producing a medium-throughput assay for rapidly assessing the rate of action of antimalarial drugs. Attempts to adapt the assay for use in a multiwell plate reader, as well as using ATP measurements as an indication of parasite vitality after drug treatment, was met with erratic results. The viability probes assay as it stands represents an improvement on other assay formats in terms of rapidity and quantification of live/compromised parasites in cultures.
- Full Text:
- Authors: Laming, Dustin
- Date: 2016
- Subjects: Malaria -- Africa , Plasmodium falciparum , Drug development , Fluorescence
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/64434 , vital:28542
- Description: Malaria is one of the most prevalent diseases in Africa and the Plasmodium falciparum species is widely accepted as the most virulent, with a fatality rate of 15 – 20 % of reported cases of infection. While various treatments have been accepted into early stage clinical trials there has been little progress towards a proven vaccine. Pending a long term solution, endemic countries rely heavily on the development of innovative drugs with acute efficacy coupled with rapids mode of action. Until recently the rate of drug action has been measured by light microscopic examination of parasite morphology using blood slides of drug treated parasite cultures at regular time intervals. This technique is tedious and, most importantly, subject to interpretation with regards to distinguishing between viable and comprised parasite cells, thus making it impossible to objectively quantitate the rate of drug action. This study aimed to develop a series of bioassays using the calcein-acetoxymethyl and propidium iodide vitality probes which would allow the rate of drug action on Plasmodium falciparum malaria parasites to be assessed and ranked in relation to each other. A novel bioassay using these fluorescent vitality probes coupled with fluorescence microscopy was developed and optimized and allowed the rate of drug action on malaria parasites to be assessed i) rapidly (in relation to current assay techniques) and ii) in a semi-quantitative manner. Extrapolation to flow cytometry for improved quantification provided favourable rankings of drug killing rates in the pilot study, however, requires further development to increase throughput and approach the ultimate goal of producing a medium-throughput assay for rapidly assessing the rate of action of antimalarial drugs. Attempts to adapt the assay for use in a multiwell plate reader, as well as using ATP measurements as an indication of parasite vitality after drug treatment, was met with erratic results. The viability probes assay as it stands represents an improvement on other assay formats in terms of rapidity and quantification of live/compromised parasites in cultures.
- Full Text:
Development of an enzyme-synergy based bioreactor system for the beneficiation of apple pomace lignocellulosic waste
- Authors: Abboo, Sagaran
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/315 , vital:19947
- Description: Due to the finite supply of non-renewable fossil fuels, agro-industrial wastes are identified as alternate, renewable sources for energy supply. Large amounts of fruit waste are generated in South Africa due to fruit juice and wine processing from apples, grapes and citrus fruit. Apple pomace is the solid residue that is left over after juice, cider and wine processing and constitutes between 25-30% of the total fruit. On a global scale millions of tonnes of apple pomace are produced; between 2006-2007 over 46 million tonnes were produced. In South Africa a total production of 244 469 tonnes were produced during the 2011- 2012 season. Initially, apple pomace was regarded as a waste by-product used for animal feed and compost in soil, however presently it is considered a source of dietary fiber and natural antioxidants like polyphenols. In addition, apple pomace has a high carbohydrate content and can be enzymatically hydrolysed to produce sugar monomers which, in turn, can be fermented by yeasts to produce bioethanol. The polyphenols present in apple pomace can be used for their health properties, and the bioethanol can be used as a replacement for fossil fuel. Apple pomace is lignocellulosic in nature and consists of hemicellulose, cellulose, lignin and pectin. A combination of enzymes such as cellulases, hemicellulases, pectinases and lignases are required to operate in synergy for the degradation of lignocellulosic biomass. This is due to the recalcitrant nature of lignocellulose. This study investigated the degradation of apple pomace using a combination of commercially obtained enzyme cocktails viz. Viscozyme L , Celluclast 1.5L and Novozyme 188. The commercial enzymes Viscozyme L and Celluclast 1.5L were added in a ratio of 1:1 (50%:50%). The final concentrations of the enzymes were 0.019 mg/ml each. Novozyme 188 was added to provide a final concentration of 0.0024 mg/ml. A novel cost effective 20L bioreactor was designed, constructed and implemented for the degradation of apple pomace to produce value added products. The hydrolysis of the apple pomace was performed initially in 1 L flasks (batch fed) and, once optimized, scaled up to a 20 L bioreactor in batch mode. The bioreactors were operated at room temperature (22 ± 2ºC) and in an unbuffered system. The sugars released were detected and quantified using an optimized validated HPLC method established in this study. The sugars released in the bioreactors were mainly glucose, galactose, arabinose, cellobiose and fructose. The polyphenols released in this study were gallic acid, catechin, epicatechin, chlorogenic acid, rutin and phloridzin, which have a number of health benefits. The simultaneous analyses of the polyphenols were performed using a newly developed and validated HPLC method established in this study. This method was developed to detect nine polyphenols simultaneously. The two HPLC methods developed and validated in this study for the analysis of sugars and polyphenols demonstrated good accuracy, precision, reproducibility, linearity, robustness and sensitivity. Both analytical methods were validated according to the International Convention on Harmonization (ICH). The HPLC parameters for sugar analysis were: refractive index (RI) as the detection mode, the stationary phase was a ligand-exchange sugar column (Shodex SP0810) and an aqueous mobile phase in isocratic mode was used. The HPLC method for polyphenols employed UV diode array detection (DAD) as the detection mode, a reverse phase column as the stationary phase and a mobile phase of consisting of 0.01 M phosphoric acid in water and 100% methanol using gradient elution mode. The highest concentrations of sugars released in the novel 20 L bioreactor with 20% apple pomace (w/v) substrate loading were as follow: glucose (6.5 mg/ml), followed by galactose (2.1 mg/ml), arabinose (1.4 mg/ml), cellobiose (0.7 mg/ml) and fructose (0.5 mg/ml). The amounts of polyphenols released at 20% (w/v) apple pomace substrate were epicatechin (0.01 mg/ml), catechin (0.002 mg/ml), rutin (0.03 mg/ml), chlorogenic acid (0.002 mg/ml) and gallic acid 0.01 (mg/ml). Two mathematical models were developed in this study for kinetic analysis of lignocellulose (apple pomace) hydrolysis in the novel 20 L bioreactor, using the experimental data generated by the above HPLC analyses. The first model, modelling with regression, defines the hydrolysis of the sugars glucose, galactose, cellobiose and arabinose produced in the novel 20 L bioreactor at 5%, 10%, 15% and 20% (w/v) substrate concentrations. The regression model describes the sugars produced in the 20 L bioreactor by minimizing the error of the sugars released by finding a value for K which minimises the function which computes the sum of squares of errors between the solution curves and the data points. The second, more complex, model developed in this study used a system of differential equations model (ODE). This model solved the system by using a numerical method, such as the Runge-Kutta method, then fitted the solution curves to the data. Both models simulated (and had the ability to predict) the production of sugars in the novel 20 L bioreactor for apple pomace hydrolysis. These two models also revealed the time at which the maximum amount of sugars were released, which revealed the optimum time to run the 20 L bioreactor in order to be more cost effective. The optimum time for maximum glucose (the main sugar used in fermentation for biofuel production) release was determined to be around 60 h. The ODE model, in addition, determined the rate at which the substrate became depleted, as well as the rate at which the enzymes became deactivated for the various substrate loadings in the 20 L bioreactor. A third model was developed to determine the optimal running cost of the bioreactor which incorporated the substrate loading and the amount of glucose (g/L) produced. The novel 20 L bioreactor constructed from cost effective materials demonstrated that agro-industrial waste can be converted to value-added products by lignocellolytic enzymes. The sugars released from apple pomace can be used in biofuel production and the polyphenols as food supplements and nutraceuticals for health benefits. This novel study contributes to agro-industrial waste beneficiation via fuel production. In addition, using agro-industrial waste for the generation of value added products (instead of mere disposal) will help prevent environmental pollution.
- Full Text:
- Authors: Abboo, Sagaran
- Date: 2016
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/315 , vital:19947
- Description: Due to the finite supply of non-renewable fossil fuels, agro-industrial wastes are identified as alternate, renewable sources for energy supply. Large amounts of fruit waste are generated in South Africa due to fruit juice and wine processing from apples, grapes and citrus fruit. Apple pomace is the solid residue that is left over after juice, cider and wine processing and constitutes between 25-30% of the total fruit. On a global scale millions of tonnes of apple pomace are produced; between 2006-2007 over 46 million tonnes were produced. In South Africa a total production of 244 469 tonnes were produced during the 2011- 2012 season. Initially, apple pomace was regarded as a waste by-product used for animal feed and compost in soil, however presently it is considered a source of dietary fiber and natural antioxidants like polyphenols. In addition, apple pomace has a high carbohydrate content and can be enzymatically hydrolysed to produce sugar monomers which, in turn, can be fermented by yeasts to produce bioethanol. The polyphenols present in apple pomace can be used for their health properties, and the bioethanol can be used as a replacement for fossil fuel. Apple pomace is lignocellulosic in nature and consists of hemicellulose, cellulose, lignin and pectin. A combination of enzymes such as cellulases, hemicellulases, pectinases and lignases are required to operate in synergy for the degradation of lignocellulosic biomass. This is due to the recalcitrant nature of lignocellulose. This study investigated the degradation of apple pomace using a combination of commercially obtained enzyme cocktails viz. Viscozyme L , Celluclast 1.5L and Novozyme 188. The commercial enzymes Viscozyme L and Celluclast 1.5L were added in a ratio of 1:1 (50%:50%). The final concentrations of the enzymes were 0.019 mg/ml each. Novozyme 188 was added to provide a final concentration of 0.0024 mg/ml. A novel cost effective 20L bioreactor was designed, constructed and implemented for the degradation of apple pomace to produce value added products. The hydrolysis of the apple pomace was performed initially in 1 L flasks (batch fed) and, once optimized, scaled up to a 20 L bioreactor in batch mode. The bioreactors were operated at room temperature (22 ± 2ºC) and in an unbuffered system. The sugars released were detected and quantified using an optimized validated HPLC method established in this study. The sugars released in the bioreactors were mainly glucose, galactose, arabinose, cellobiose and fructose. The polyphenols released in this study were gallic acid, catechin, epicatechin, chlorogenic acid, rutin and phloridzin, which have a number of health benefits. The simultaneous analyses of the polyphenols were performed using a newly developed and validated HPLC method established in this study. This method was developed to detect nine polyphenols simultaneously. The two HPLC methods developed and validated in this study for the analysis of sugars and polyphenols demonstrated good accuracy, precision, reproducibility, linearity, robustness and sensitivity. Both analytical methods were validated according to the International Convention on Harmonization (ICH). The HPLC parameters for sugar analysis were: refractive index (RI) as the detection mode, the stationary phase was a ligand-exchange sugar column (Shodex SP0810) and an aqueous mobile phase in isocratic mode was used. The HPLC method for polyphenols employed UV diode array detection (DAD) as the detection mode, a reverse phase column as the stationary phase and a mobile phase of consisting of 0.01 M phosphoric acid in water and 100% methanol using gradient elution mode. The highest concentrations of sugars released in the novel 20 L bioreactor with 20% apple pomace (w/v) substrate loading were as follow: glucose (6.5 mg/ml), followed by galactose (2.1 mg/ml), arabinose (1.4 mg/ml), cellobiose (0.7 mg/ml) and fructose (0.5 mg/ml). The amounts of polyphenols released at 20% (w/v) apple pomace substrate were epicatechin (0.01 mg/ml), catechin (0.002 mg/ml), rutin (0.03 mg/ml), chlorogenic acid (0.002 mg/ml) and gallic acid 0.01 (mg/ml). Two mathematical models were developed in this study for kinetic analysis of lignocellulose (apple pomace) hydrolysis in the novel 20 L bioreactor, using the experimental data generated by the above HPLC analyses. The first model, modelling with regression, defines the hydrolysis of the sugars glucose, galactose, cellobiose and arabinose produced in the novel 20 L bioreactor at 5%, 10%, 15% and 20% (w/v) substrate concentrations. The regression model describes the sugars produced in the 20 L bioreactor by minimizing the error of the sugars released by finding a value for K which minimises the function which computes the sum of squares of errors between the solution curves and the data points. The second, more complex, model developed in this study used a system of differential equations model (ODE). This model solved the system by using a numerical method, such as the Runge-Kutta method, then fitted the solution curves to the data. Both models simulated (and had the ability to predict) the production of sugars in the novel 20 L bioreactor for apple pomace hydrolysis. These two models also revealed the time at which the maximum amount of sugars were released, which revealed the optimum time to run the 20 L bioreactor in order to be more cost effective. The optimum time for maximum glucose (the main sugar used in fermentation for biofuel production) release was determined to be around 60 h. The ODE model, in addition, determined the rate at which the substrate became depleted, as well as the rate at which the enzymes became deactivated for the various substrate loadings in the 20 L bioreactor. A third model was developed to determine the optimal running cost of the bioreactor which incorporated the substrate loading and the amount of glucose (g/L) produced. The novel 20 L bioreactor constructed from cost effective materials demonstrated that agro-industrial waste can be converted to value-added products by lignocellolytic enzymes. The sugars released from apple pomace can be used in biofuel production and the polyphenols as food supplements and nutraceuticals for health benefits. This novel study contributes to agro-industrial waste beneficiation via fuel production. In addition, using agro-industrial waste for the generation of value added products (instead of mere disposal) will help prevent environmental pollution.
- Full Text:
Dialogues of sexualities: An action research project
- Authors: Graham, Nicola Susan Jearey
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3275 , http://hdl.handle.net/10962/d1021271
- Description: Risky and abusive sexual behaviours, stemming largely from inequitable gendered norms, are a pervasive feature of the South African socio-sexual landscape. Literature shows that sexuality education programmes can be effective in reducing risky sexual practices, but South African school sexuality education has been shown to be largely inadequate. The question arises as to how to engage with high school learners about sexualities in meaningful ways. In an attempt to answer this, I implemented a dialogical sexuality action research project at a lower middle class urban high school. Freirian principles of critical consciousness and dialogical pedagogy were utilized, and these were infused with feminist post-structural understandings of a discursively constituted subject. The initial consultative process started in 2012 with two projects at the school. Data from these projects, and a further consultation with the school principal, provided baseline information on the gendered norms and the sexuality education in the school. I then instituted a dialogical sexuality intervention with a group of Grade 10 learners, aiming to bring gendered and sexual norms to visibility, to trouble them (thereby promoting participants’ critical consciousness around gendered norms), and to provide recognition for participants in a variety of subject positions. Ten sessions were conducted, with the focus of each session being planned by the group. The action research project attempted to promote understandings of the processes required to facilitate such aims. The dialogical format of the group generated curiosity and engagement, and there were suggestions that some participants were taking up safe-sex messages in a reflexive manner. A partial normalisation of some ‘hidden’ aspects of sex, particularly around issues pertaining to female sexuality, was enabled, and critical consciousness around the gendered inequities in ‘cheating’ was promoted. However, abstinence was relatively silenced, and male same-sex remained heavily stigmatised. No substantial action component beyond the group meetings was generated. Participant feedback indicated that they placed great value on the dialogical processes in the group, and that they enjoyed being able to talk about sexual and other personal aspects of their lives. I theorise that the value of the group was in the recognition that participants received as they were positioned in a variety of subject positions. Whilst dialogue was shown to be extremely valuable, there were suggestions that other, non-dialogical modes of recognition were also needed by participants.
- Full Text:
- Authors: Graham, Nicola Susan Jearey
- Date: 2016
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3275 , http://hdl.handle.net/10962/d1021271
- Description: Risky and abusive sexual behaviours, stemming largely from inequitable gendered norms, are a pervasive feature of the South African socio-sexual landscape. Literature shows that sexuality education programmes can be effective in reducing risky sexual practices, but South African school sexuality education has been shown to be largely inadequate. The question arises as to how to engage with high school learners about sexualities in meaningful ways. In an attempt to answer this, I implemented a dialogical sexuality action research project at a lower middle class urban high school. Freirian principles of critical consciousness and dialogical pedagogy were utilized, and these were infused with feminist post-structural understandings of a discursively constituted subject. The initial consultative process started in 2012 with two projects at the school. Data from these projects, and a further consultation with the school principal, provided baseline information on the gendered norms and the sexuality education in the school. I then instituted a dialogical sexuality intervention with a group of Grade 10 learners, aiming to bring gendered and sexual norms to visibility, to trouble them (thereby promoting participants’ critical consciousness around gendered norms), and to provide recognition for participants in a variety of subject positions. Ten sessions were conducted, with the focus of each session being planned by the group. The action research project attempted to promote understandings of the processes required to facilitate such aims. The dialogical format of the group generated curiosity and engagement, and there were suggestions that some participants were taking up safe-sex messages in a reflexive manner. A partial normalisation of some ‘hidden’ aspects of sex, particularly around issues pertaining to female sexuality, was enabled, and critical consciousness around the gendered inequities in ‘cheating’ was promoted. However, abstinence was relatively silenced, and male same-sex remained heavily stigmatised. No substantial action component beyond the group meetings was generated. Participant feedback indicated that they placed great value on the dialogical processes in the group, and that they enjoyed being able to talk about sexual and other personal aspects of their lives. I theorise that the value of the group was in the recognition that participants received as they were positioned in a variety of subject positions. Whilst dialogue was shown to be extremely valuable, there were suggestions that other, non-dialogical modes of recognition were also needed by participants.
- Full Text: