Learners' numeracy progression and the role of mediation in the context of two after school mathematics clubs
- Authors: Stott, Deborah Ann
- Date: 2015
- Subjects: Mathematics -- Study and teaching (Elementary) -- South Africa , After-school programs -- South Africa , Numeracy -- Study and teaching (Elementary) -- South Africa , Learning, Psychology of , Education -- Research -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2017 , http://hdl.handle.net/10962/d1017181
- Description: National and international assessment results, research studies and reports point to South Africa as having educational challenges, specifically with mathematics, science and language. Addressing some of these issues is a key aim for the SANC project at Rhodes University, the context in which this study takes place. Working from a broad Vygotskian perspective of learning and development, this study had a dual focus and investigated how Grade 3 learners’ mathematical proficiency progressed (or not) whilst participating in after school maths clubs over the course of a year, and explored how the mediation offered in the clubs enabled or constrained the emergence of zones of proximal development (ZPD) and thus learning for the club learners. Methodologically, this study works within a largely qualitative, interpretive research paradigm and is designed using a longitudinal case study research strategy. Two after school maths clubs formed the empirical field. The study drew on a range of data collection methods to investigate the dual nature of the research questions for Grade 3 learners. Examples include adapted one-to-one mathematical proficiency interviews and paired task based interviews. The study highlighted the relationship between the multiple roles I played both within the research study and within the SANC project context and emphasises the influence and future implications for these various roles within the SANC project and beyond in terms of my own role as club mentor, for the future design of the SANC project maths club programme and for broader teacher and club facilitator development within and beyond the project. This study has offered insight into how mathematical proficiency may develop in Grade 3 South African learners and as such is an important contribution to the newly developing field of both numeracy and primary educational research in Southern Africa. Additionally, the research findings point to the clubs, as an example of an out-of-school time (OST) programme, providing potentially enabling spaces for both recovery and extension of mathematical proficiency in learners as these spaces are free from several contextual constraints that teachers face in their classrooms. Furthermore, it was found that learners showed development of their conceptual understanding, procedural fluency and adaptive reasoning as proposed by Kilpatrick, Swafford and Findell (2001). The use of various elements of the Maths Recovery (MR) programme (Wright, 2003) in the research process has highlighted various important contributions for broader research. For example, the need to investigate less time consuming approaches to both diagnostic assessment and learner mathematical profiling. Findings from this study support Meira and Lerman’s (2001, 2009) recently developed notion that catching attention is key to the creation or emergence of a ZPD. The study found that a combination of ‘attention catching’ and ‘tuning in’ enabled the creation (emergence) and sustainment of ZPDs in club learners. The study proposed the notion of tuning in where participants in a mathematical interaction continually adjust to each other in order to communicate mathematically. Furthermore, the study found that when attention is not caught or the participants are not tuned in, the learning activity may still be useful in assisting learners to consolidate their existing learning and / or build confidence and as such is particularly relevant to the South African context where fluency in calculating is weak (Hoadley, 2012; Schollar, 2008). This emergent notion of ‘flow’ additionally can play a supporting role in the emergence of a ZPD. The study also found that the manner in which the mediation was offered is important. The results show that the mathematical contributions learners make during interactions captured the mentors’ attention and resulted in mediation that was intentional but spontaneous, flexible, responsive and in-the-moment. This study makes theoretical and methodological contributions to various aspects of mathematics education research particularly with regard to how ZPDs emerge and are sustained and how mediation is offered to facilitate the emergence of ZPDs. Additionally, some aspects of the Learning Framework in Number (LFIN) as part of the Maths Recovery programme have been extended to work in a South African after school club context and to provide useful information for both learner progression over time and for planning of club activities. As such this study thus also contributes to the newly developing field of primary mathematics research in South Africa and to the body of research on primary after school learning programmes both locally and internationally.
- Full Text:
- Date Issued: 2015
- Authors: Stott, Deborah Ann
- Date: 2015
- Subjects: Mathematics -- Study and teaching (Elementary) -- South Africa , After-school programs -- South Africa , Numeracy -- Study and teaching (Elementary) -- South Africa , Learning, Psychology of , Education -- Research -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2017 , http://hdl.handle.net/10962/d1017181
- Description: National and international assessment results, research studies and reports point to South Africa as having educational challenges, specifically with mathematics, science and language. Addressing some of these issues is a key aim for the SANC project at Rhodes University, the context in which this study takes place. Working from a broad Vygotskian perspective of learning and development, this study had a dual focus and investigated how Grade 3 learners’ mathematical proficiency progressed (or not) whilst participating in after school maths clubs over the course of a year, and explored how the mediation offered in the clubs enabled or constrained the emergence of zones of proximal development (ZPD) and thus learning for the club learners. Methodologically, this study works within a largely qualitative, interpretive research paradigm and is designed using a longitudinal case study research strategy. Two after school maths clubs formed the empirical field. The study drew on a range of data collection methods to investigate the dual nature of the research questions for Grade 3 learners. Examples include adapted one-to-one mathematical proficiency interviews and paired task based interviews. The study highlighted the relationship between the multiple roles I played both within the research study and within the SANC project context and emphasises the influence and future implications for these various roles within the SANC project and beyond in terms of my own role as club mentor, for the future design of the SANC project maths club programme and for broader teacher and club facilitator development within and beyond the project. This study has offered insight into how mathematical proficiency may develop in Grade 3 South African learners and as such is an important contribution to the newly developing field of both numeracy and primary educational research in Southern Africa. Additionally, the research findings point to the clubs, as an example of an out-of-school time (OST) programme, providing potentially enabling spaces for both recovery and extension of mathematical proficiency in learners as these spaces are free from several contextual constraints that teachers face in their classrooms. Furthermore, it was found that learners showed development of their conceptual understanding, procedural fluency and adaptive reasoning as proposed by Kilpatrick, Swafford and Findell (2001). The use of various elements of the Maths Recovery (MR) programme (Wright, 2003) in the research process has highlighted various important contributions for broader research. For example, the need to investigate less time consuming approaches to both diagnostic assessment and learner mathematical profiling. Findings from this study support Meira and Lerman’s (2001, 2009) recently developed notion that catching attention is key to the creation or emergence of a ZPD. The study found that a combination of ‘attention catching’ and ‘tuning in’ enabled the creation (emergence) and sustainment of ZPDs in club learners. The study proposed the notion of tuning in where participants in a mathematical interaction continually adjust to each other in order to communicate mathematically. Furthermore, the study found that when attention is not caught or the participants are not tuned in, the learning activity may still be useful in assisting learners to consolidate their existing learning and / or build confidence and as such is particularly relevant to the South African context where fluency in calculating is weak (Hoadley, 2012; Schollar, 2008). This emergent notion of ‘flow’ additionally can play a supporting role in the emergence of a ZPD. The study also found that the manner in which the mediation was offered is important. The results show that the mathematical contributions learners make during interactions captured the mentors’ attention and resulted in mediation that was intentional but spontaneous, flexible, responsive and in-the-moment. This study makes theoretical and methodological contributions to various aspects of mathematics education research particularly with regard to how ZPDs emerge and are sustained and how mediation is offered to facilitate the emergence of ZPDs. Additionally, some aspects of the Learning Framework in Number (LFIN) as part of the Maths Recovery programme have been extended to work in a South African after school club context and to provide useful information for both learner progression over time and for planning of club activities. As such this study thus also contributes to the newly developing field of primary mathematics research in South Africa and to the body of research on primary after school learning programmes both locally and internationally.
- Full Text:
- Date Issued: 2015
Metallophthalocyanine-gold nanoparticle conjugates for photodynamic antimicrobial chemotherapy
- Mthethwa, Thandekile Phakamisiwe
- Authors: Mthethwa, Thandekile Phakamisiwe
- Date: 2015
- Subjects: Nanochemistry , Phthalocyanines , Photochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4543 , http://hdl.handle.net/10962/d1017923
- Description: This thesis presents the synthesis of neutral and cationic metallophthalocyanines and their gold nanoparticles conjugates. The spectroscopic characterization of these compounds is presented herein. The studies presented in this work shows that the conjugation of gold nanoparticles influenced both photophysical and photochemical properties. Gold nanoparticles were found to enhance the singlet oxygen quantum yield while lowering the fluorescence quantum yields. This work also looks at the effect of anisotropic gold nanoparticles such as nanorods and bipyramids on the photophysical behaviour of the metallophthalocyanines. The effect of the size of the gold nanorods was investigated herein. The results show that photophysical and photochemical properties can be influenced by both size and shape of the nanoparticles. Physical characterization about the loading of nanoparticles was also looked into. Parameters such as the surface area, the number of surface atoms, the number of atoms as well as the number of nanoparticles loaded on the surface of the phthalocyanines were studied. The self-assembled monolayers formed by phthalocyanines on gold surfaces were studied using the X-ray photoelectron spectroscopy (XPS). The gold nanoparticles synthesized herein include both organic and water soluble, different capping agents (citrate, tetraammonium bromide (TAOBr) and cetrimethylammonium bromide (CTAB). The concentration of the gold nanoparticles was measured on the inductively coupled plasma (ICP) and their size and shape were obtained from the transmission electron microscopy (TEM) images. A cationic aluminium phthalocyanine and its conjugates were used for photoinactivation of bacteria and fungi. The results show significant reduction and higher activity in the presence of gold nanoparticles, especially nanorods. A small chapter in this work presents an attempted work on the binding of metallothionein protein with protophorphyrin (IX). The pH and concentration dependent binding studies were investigated
- Full Text:
- Date Issued: 2015
- Authors: Mthethwa, Thandekile Phakamisiwe
- Date: 2015
- Subjects: Nanochemistry , Phthalocyanines , Photochemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4543 , http://hdl.handle.net/10962/d1017923
- Description: This thesis presents the synthesis of neutral and cationic metallophthalocyanines and their gold nanoparticles conjugates. The spectroscopic characterization of these compounds is presented herein. The studies presented in this work shows that the conjugation of gold nanoparticles influenced both photophysical and photochemical properties. Gold nanoparticles were found to enhance the singlet oxygen quantum yield while lowering the fluorescence quantum yields. This work also looks at the effect of anisotropic gold nanoparticles such as nanorods and bipyramids on the photophysical behaviour of the metallophthalocyanines. The effect of the size of the gold nanorods was investigated herein. The results show that photophysical and photochemical properties can be influenced by both size and shape of the nanoparticles. Physical characterization about the loading of nanoparticles was also looked into. Parameters such as the surface area, the number of surface atoms, the number of atoms as well as the number of nanoparticles loaded on the surface of the phthalocyanines were studied. The self-assembled monolayers formed by phthalocyanines on gold surfaces were studied using the X-ray photoelectron spectroscopy (XPS). The gold nanoparticles synthesized herein include both organic and water soluble, different capping agents (citrate, tetraammonium bromide (TAOBr) and cetrimethylammonium bromide (CTAB). The concentration of the gold nanoparticles was measured on the inductively coupled plasma (ICP) and their size and shape were obtained from the transmission electron microscopy (TEM) images. A cationic aluminium phthalocyanine and its conjugates were used for photoinactivation of bacteria and fungi. The results show significant reduction and higher activity in the presence of gold nanoparticles, especially nanorods. A small chapter in this work presents an attempted work on the binding of metallothionein protein with protophorphyrin (IX). The pH and concentration dependent binding studies were investigated
- Full Text:
- Date Issued: 2015
Minding your own game : self-regulation and psychological momentum among golfers
- Authors: Kingma, Graham
- Date: 2015
- Subjects: Golf -- Strategic aspects , Golf -- Psychological aspects , Athletes , Self-control , Golfers -- Conduct of life
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3260 , http://hdl.handle.net/10962/d1017883
- Description: Psychological momentum (PM) is often regarded as an important phenomenon that influences athlete performance. Nevertheless, conceptualisations of PM are criticised for being speculative, vague and impractical for scientific inquiry. In contrast, self-regulation is a long-standing, well researched concept used to explain performance outcomes, yet not clearly integrated in current PM conceptualisations. Hence, this thesis explores self-regulation relative to PM. Golf was considered to be an appropriate context for the empirical inquiries on the basis that it serves as a metaphor for managing life’s challenges. Three studies were conducted. The first study entailed a systematic conceptual analysis of PM based on previous conceptualisations and studies in relevant scientific literature. Self-regulatory processes were identified among the key psychological mechanisms and moderators related to PM. The second study aimed to identify key self-regulation strategies in PM experiences among 16 golfers. A mixed method approach including novel “walk-along” and “think aloud” data collection techniques was used. An inductive thematic analysis yielded a comprehensive typology golfing strategies. Nevertheless, the study did not find consistent strategy patterns in positive or negative PM phases. The third study explored the self-regulation of identity (ego-regulation) in relation to PM phases. A staggered multiple-baseline single-case research methodology was used with five golfers (three professionals and two amateurs). Ego-regulation was manipulated through a mindfulness-based schema mode program tailored to golf (Mindfulness for Golf; MFG). Pre-, mid- and post-intervention data showed positive changes among the participants on two dimensions of PM as well as performance outcomes. Overall the results suggest that golfers use idiosyncratic self-regulation processes to facilitate performance, but these are not directly linked to PM phases. Nonetheless, there are promising indications that enhancing ego-regulation through the MFG program facilitates positive momentum among golfers. Based on the results of the studies in this thesis, and for the sake of scientific parsimony and pragmatism, it is recommended that self-regulation models incorporating motivation are used to explain momentum in athletic activity. In this view, PM has the function of describing, not influencing, goal-driven performance
- Full Text:
- Date Issued: 2015
- Authors: Kingma, Graham
- Date: 2015
- Subjects: Golf -- Strategic aspects , Golf -- Psychological aspects , Athletes , Self-control , Golfers -- Conduct of life
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3260 , http://hdl.handle.net/10962/d1017883
- Description: Psychological momentum (PM) is often regarded as an important phenomenon that influences athlete performance. Nevertheless, conceptualisations of PM are criticised for being speculative, vague and impractical for scientific inquiry. In contrast, self-regulation is a long-standing, well researched concept used to explain performance outcomes, yet not clearly integrated in current PM conceptualisations. Hence, this thesis explores self-regulation relative to PM. Golf was considered to be an appropriate context for the empirical inquiries on the basis that it serves as a metaphor for managing life’s challenges. Three studies were conducted. The first study entailed a systematic conceptual analysis of PM based on previous conceptualisations and studies in relevant scientific literature. Self-regulatory processes were identified among the key psychological mechanisms and moderators related to PM. The second study aimed to identify key self-regulation strategies in PM experiences among 16 golfers. A mixed method approach including novel “walk-along” and “think aloud” data collection techniques was used. An inductive thematic analysis yielded a comprehensive typology golfing strategies. Nevertheless, the study did not find consistent strategy patterns in positive or negative PM phases. The third study explored the self-regulation of identity (ego-regulation) in relation to PM phases. A staggered multiple-baseline single-case research methodology was used with five golfers (three professionals and two amateurs). Ego-regulation was manipulated through a mindfulness-based schema mode program tailored to golf (Mindfulness for Golf; MFG). Pre-, mid- and post-intervention data showed positive changes among the participants on two dimensions of PM as well as performance outcomes. Overall the results suggest that golfers use idiosyncratic self-regulation processes to facilitate performance, but these are not directly linked to PM phases. Nonetheless, there are promising indications that enhancing ego-regulation through the MFG program facilitates positive momentum among golfers. Based on the results of the studies in this thesis, and for the sake of scientific parsimony and pragmatism, it is recommended that self-regulation models incorporating motivation are used to explain momentum in athletic activity. In this view, PM has the function of describing, not influencing, goal-driven performance
- Full Text:
- Date Issued: 2015
Modification and application of the decentralised wastewater treatment technology for greywater treatment to reduce water needs
- Authors: Ngqwala, Nosiphiwe P
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/103714 , vital:32290
- Description: Expected release date-April 2017
- Full Text: false
- Date Issued: 2015
- Authors: Ngqwala, Nosiphiwe P
- Date: 2015
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/103714 , vital:32290
- Description: Expected release date-April 2017
- Full Text: false
- Date Issued: 2015
Molecular systematics and biology of two closely related blowflies : Lucilia sericata and Lucilia cuprina
- Authors: Williams, Kirstin Alexa
- Date: 2015
- Subjects: Lucilia sericata , Lucilia cuprina
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5934 , http://hdl.handle.net/10962/d1017812
- Description: The greenbottle blowflies, Lucilia sericata (Meigen, 1826) and Lucilia cuprina (Wiedemann, 1830) (Diptera: Calliphoridae) are very difficult to distinguish on the basis of their external morphology. The literature suggests that these two species may be interbreeding. Sequencing two nuclear (28S rRNA and Period) and one mitochondrial (COI) gene indicated that there has been an ancient hybridization event and that mtDNA of L. sericata has become fixed in a lineage of L. cuprina through mtDNA introgression, possibly involving Wolbachia infection. This has implications for identifications of these species based on mtDNA alone. No study has shown explicitly that hybrids of L. sericata and L. cuprina can be identified morphologically. Morphological characters used to identify L. sericata and L. cuprina were scored and tested using specimens of both species and known hybrids. Discriminant function analysis of the characters successfully separated the specimens into three unambiguous groups – L. sericata, L. cuprina and hybrids. This is the first evidence that hybrids of these two species can be identified from physical characteristics.Lucilia sericata and L. cuprina have medical, veterinary and forensic importance. Knowing their distribution in South Africa would allow more effective management and utilisation of these flies. Their predicted geographic distributions in South Africa were modelled using maximum entropy analysis of selected climatic variables. The most important environmental variables in modelling their distributions were magnitude of monthly rainfall and the magnitude of the monthly maximum temperature for L. sericata, and the seasonal variation in monthly mean humidity and magnitude of monthly rainfall for L. cuprina. Both species have a widespread distribution in South Africa and one therefore cannot identify specimens of these flies by locality of capture alone.Luciliinae is a diverse and geographically widespread subfamily containing four genera - Hemipyrellia, Lucilia, Dyscritomyia and Hypopygiopsis – that all contain parasitic species ranging from saprophages to obligate parasites. The phylogenetic relationships between these genera are unclear. The 28S rRNA, COI and Period genes of 14 species of Lucilia and Hemipyrellia were partially sequenced and analysed together with 11sequences from GenBank and the Barcode of Life Database (BOLD). Lucilia sericata and L. cuprina were shown to be sister-species. Three cases of paraphylly were identified within Lucilia that affects identification of these species using mtDNA alone. Hemipyrellia consistently caused Lucilia to be paraphyletic when it was included in analyses, so Hemipyrellia should be synonymized with Lucilia. The relationships of Dyscritomyia and Hypopygiopsis to Lucilia are unclear and further studies are required. No geographic pattern was found within the different forms of parasitism within this group, but the different degrees of parasitism were phylogenetically clustered.
- Full Text:
- Date Issued: 2015
- Authors: Williams, Kirstin Alexa
- Date: 2015
- Subjects: Lucilia sericata , Lucilia cuprina
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5934 , http://hdl.handle.net/10962/d1017812
- Description: The greenbottle blowflies, Lucilia sericata (Meigen, 1826) and Lucilia cuprina (Wiedemann, 1830) (Diptera: Calliphoridae) are very difficult to distinguish on the basis of their external morphology. The literature suggests that these two species may be interbreeding. Sequencing two nuclear (28S rRNA and Period) and one mitochondrial (COI) gene indicated that there has been an ancient hybridization event and that mtDNA of L. sericata has become fixed in a lineage of L. cuprina through mtDNA introgression, possibly involving Wolbachia infection. This has implications for identifications of these species based on mtDNA alone. No study has shown explicitly that hybrids of L. sericata and L. cuprina can be identified morphologically. Morphological characters used to identify L. sericata and L. cuprina were scored and tested using specimens of both species and known hybrids. Discriminant function analysis of the characters successfully separated the specimens into three unambiguous groups – L. sericata, L. cuprina and hybrids. This is the first evidence that hybrids of these two species can be identified from physical characteristics.Lucilia sericata and L. cuprina have medical, veterinary and forensic importance. Knowing their distribution in South Africa would allow more effective management and utilisation of these flies. Their predicted geographic distributions in South Africa were modelled using maximum entropy analysis of selected climatic variables. The most important environmental variables in modelling their distributions were magnitude of monthly rainfall and the magnitude of the monthly maximum temperature for L. sericata, and the seasonal variation in monthly mean humidity and magnitude of monthly rainfall for L. cuprina. Both species have a widespread distribution in South Africa and one therefore cannot identify specimens of these flies by locality of capture alone.Luciliinae is a diverse and geographically widespread subfamily containing four genera - Hemipyrellia, Lucilia, Dyscritomyia and Hypopygiopsis – that all contain parasitic species ranging from saprophages to obligate parasites. The phylogenetic relationships between these genera are unclear. The 28S rRNA, COI and Period genes of 14 species of Lucilia and Hemipyrellia were partially sequenced and analysed together with 11sequences from GenBank and the Barcode of Life Database (BOLD). Lucilia sericata and L. cuprina were shown to be sister-species. Three cases of paraphylly were identified within Lucilia that affects identification of these species using mtDNA alone. Hemipyrellia consistently caused Lucilia to be paraphyletic when it was included in analyses, so Hemipyrellia should be synonymized with Lucilia. The relationships of Dyscritomyia and Hypopygiopsis to Lucilia are unclear and further studies are required. No geographic pattern was found within the different forms of parasitism within this group, but the different degrees of parasitism were phylogenetically clustered.
- Full Text:
- Date Issued: 2015
Negotiating historical continuities in contested terrain : a narrative-based reflection on the post-apartheid psychosocial legacies of conscription into the South African Defence Force
- Authors: Edlmann, Tessa Margaret
- Date: 2015
- Subjects: South Africa. National Defence Force , Draft -- South Africa -- History -- 20th century , Draft -- Psychological aspects , Masculinity -- South Africa , Sociology, Military -- South Africa , Whites -- Race identity -- South Africa , South Africa -- Politics and government -- 1948-1994 , Narrative inquiry (Research method)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2608 , http://hdl.handle.net/10962/d1012811
- Description: For a 25-year period during the apartheid era in South Africa, all school-leaving white men were issued with a compulsory call-up to national military service in the South African Defence Force. It is estimated that 600 000 men were conscripted between 1968 and 1993, undergoing military training and being deployed in Namibia, Angola and South Africa. The purpose of this system of military conscription was to support both the apartheid state’s role in the “Border War” in Namibia and Angola and the suppression of anti-apartheid resistance within South Africa. It formed part of the National Party’s strategy of a “total response” to what it perceived as the “total onslaught” of communism and African nationalism. While recruiting and training young white men was the focus of the apartheid government’s strategy, all of white South African society was caught up in supporting, contesting, avoiding and resisting this system in one way or another. Rather than being a purely military endeavour, conscription into the SADF therefore comprised a social and political system with wide-ranging ramifications. The 1994 democratic elections in South Africa heralded the advent of a very different political, social and economic system to what had gone before. The focus of this research is SADF conscripts’ narrations of identity in the contested narrative terrain of post-apartheid South Africa. The thesis begins with a contextual framing of the historical, social and political systems of which conscription was a part. Drawing on narrative psychology as a theoretical framework, the thesis explores discursive resources of whiteness, masculinities and perceptions of threat in conscripts’ narrations of identity, the construction of memory fields in narrating memories of war and possible trauma, and the notions of moral injury and moral repair in dealing with legacies of war. Using a narrative discursive approach, the thesis then reflects on historical temporal threads, and narrative patterns that emerge when analysing a range of texts about the psychosocial legacies of conscription, including interviews, research, memoirs, plays, media reports, video documentaries, blogs and photographic exhibitions. Throughout the thesis, conscripts’ and others’ accounts of conscription and its legacies are regarded as cultural texts. This serves as a means to highlight both contextual narrative negotiations and the narrative-discursive patterns of conscripts’ personal accounts of their identities in the post-apartheid narrative terrain. The original contribution of this research is the development of conceptual and theoretical framings of the post-apartheid legacies of conscription. Key to this has been the use of narrative-based approaches to highlight the narrative-discursive patterns, memory fields and negotiations of narrative terrains at work in texts that focus on various aspects of conscription and its ongoing aftereffects. The concept of temporal threads has been developed to account for the emergence and shifts in these patterns over time. Existing narrative-discursive theory has formed the basis for conscripts’ negotiations of identity being identified as acts of narrative reinforcement and narrative repair. The thesis concludes with reflections on the future possibilities for articulating and supporting narrative repair that enables a shift away from historical discursive laagers and a reconfiguration of the narrative terrain within which conscripts narrate their identities. , Also known as: Edlmann, Theresa
- Full Text:
- Date Issued: 2015
- Authors: Edlmann, Tessa Margaret
- Date: 2015
- Subjects: South Africa. National Defence Force , Draft -- South Africa -- History -- 20th century , Draft -- Psychological aspects , Masculinity -- South Africa , Sociology, Military -- South Africa , Whites -- Race identity -- South Africa , South Africa -- Politics and government -- 1948-1994 , Narrative inquiry (Research method)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2608 , http://hdl.handle.net/10962/d1012811
- Description: For a 25-year period during the apartheid era in South Africa, all school-leaving white men were issued with a compulsory call-up to national military service in the South African Defence Force. It is estimated that 600 000 men were conscripted between 1968 and 1993, undergoing military training and being deployed in Namibia, Angola and South Africa. The purpose of this system of military conscription was to support both the apartheid state’s role in the “Border War” in Namibia and Angola and the suppression of anti-apartheid resistance within South Africa. It formed part of the National Party’s strategy of a “total response” to what it perceived as the “total onslaught” of communism and African nationalism. While recruiting and training young white men was the focus of the apartheid government’s strategy, all of white South African society was caught up in supporting, contesting, avoiding and resisting this system in one way or another. Rather than being a purely military endeavour, conscription into the SADF therefore comprised a social and political system with wide-ranging ramifications. The 1994 democratic elections in South Africa heralded the advent of a very different political, social and economic system to what had gone before. The focus of this research is SADF conscripts’ narrations of identity in the contested narrative terrain of post-apartheid South Africa. The thesis begins with a contextual framing of the historical, social and political systems of which conscription was a part. Drawing on narrative psychology as a theoretical framework, the thesis explores discursive resources of whiteness, masculinities and perceptions of threat in conscripts’ narrations of identity, the construction of memory fields in narrating memories of war and possible trauma, and the notions of moral injury and moral repair in dealing with legacies of war. Using a narrative discursive approach, the thesis then reflects on historical temporal threads, and narrative patterns that emerge when analysing a range of texts about the psychosocial legacies of conscription, including interviews, research, memoirs, plays, media reports, video documentaries, blogs and photographic exhibitions. Throughout the thesis, conscripts’ and others’ accounts of conscription and its legacies are regarded as cultural texts. This serves as a means to highlight both contextual narrative negotiations and the narrative-discursive patterns of conscripts’ personal accounts of their identities in the post-apartheid narrative terrain. The original contribution of this research is the development of conceptual and theoretical framings of the post-apartheid legacies of conscription. Key to this has been the use of narrative-based approaches to highlight the narrative-discursive patterns, memory fields and negotiations of narrative terrains at work in texts that focus on various aspects of conscription and its ongoing aftereffects. The concept of temporal threads has been developed to account for the emergence and shifts in these patterns over time. Existing narrative-discursive theory has formed the basis for conscripts’ negotiations of identity being identified as acts of narrative reinforcement and narrative repair. The thesis concludes with reflections on the future possibilities for articulating and supporting narrative repair that enables a shift away from historical discursive laagers and a reconfiguration of the narrative terrain within which conscripts narrate their identities. , Also known as: Edlmann, Theresa
- Full Text:
- Date Issued: 2015
Network simulation for professional audio networks
- Authors: Otten, Fred
- Date: 2015
- Subjects: Sound engineers , Ethernet (Local area network system) , Computer networks , Computer simulation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4713 , http://hdl.handle.net/10962/d1017935
- Description: Audio Engineers are required to design and deploy large multi-channel sound systems which meet a set of requirements and use networking technologies such as Firewire and Ethernet AVB. Bandwidth utilisation and parameter groupings are among the factors which need to be considered in these designs. An implementation of an extensible, generic simulation framework would allow audio engineers to easily compare protocols and networking technologies and get near real time responses with regards to bandwidth utilisation. Our hypothesis is that an application-level capability can be developed which uses a network simulation framework to enable this process and enhances the audio engineer’s experience of designing and configuring a network. This thesis presents a new, extensible simulation framework which can be utilised to simulate professional audio networks. This framework is utilised to develop an application - AudioNetSim - based on the requirements of an audio engineer. The thesis describes the AudioNetSim models and implementations for Ethernet AVB, Firewire and the AES- 64 control protocol. AudioNetSim enables bandwidth usage determination for any network configuration and connection scenario and is used to compare Firewire and Ethernet AVB bandwidth utilisation. It also applies graph theory to the circular join problem and provides a solution to detect circular joins.
- Full Text:
- Date Issued: 2015
- Authors: Otten, Fred
- Date: 2015
- Subjects: Sound engineers , Ethernet (Local area network system) , Computer networks , Computer simulation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4713 , http://hdl.handle.net/10962/d1017935
- Description: Audio Engineers are required to design and deploy large multi-channel sound systems which meet a set of requirements and use networking technologies such as Firewire and Ethernet AVB. Bandwidth utilisation and parameter groupings are among the factors which need to be considered in these designs. An implementation of an extensible, generic simulation framework would allow audio engineers to easily compare protocols and networking technologies and get near real time responses with regards to bandwidth utilisation. Our hypothesis is that an application-level capability can be developed which uses a network simulation framework to enable this process and enhances the audio engineer’s experience of designing and configuring a network. This thesis presents a new, extensible simulation framework which can be utilised to simulate professional audio networks. This framework is utilised to develop an application - AudioNetSim - based on the requirements of an audio engineer. The thesis describes the AudioNetSim models and implementations for Ethernet AVB, Firewire and the AES- 64 control protocol. AudioNetSim enables bandwidth usage determination for any network configuration and connection scenario and is used to compare Firewire and Ethernet AVB bandwidth utilisation. It also applies graph theory to the circular join problem and provides a solution to detect circular joins.
- Full Text:
- Date Issued: 2015
Neurocognitive effects of head and body collisions on club level rugby union players
- Authors: Zoccola, Diana
- Date: 2015
- Subjects: Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3257 , http://hdl.handle.net/10962/d1016397
- Description: The objective of the study was to investigate the cumulative neurocognitive effects of repetitive concussive and subconcussive events in club level Rugby Union (hereafter rugby) during the course of one rugby season, in a combined group and individualized case-based approach. Amateur adult club level rugby players (n = 20) were compared with a non-contact control group (n = 22) of equivalent age, years of education and estimated IQ (p = > .05, in all instances), although the two groups were clearly differentiated on the basis of a history of reported concussions (p = < .05). Video analyses documented the tackling maneuvers observed amongst the players during all matches across the rugby season revealing a sobering average of more than a thousand tackles per player, excluding any contact practice sessions. Five rugby players (n = 5) who were observed to have a head jarring event were also isolated for individualized postconcussive follow-up analysis of their neurocognitive profiles. Measures included the ImPACT Verbal and Visual Memory, Visual Motor Speed and Reaction Time composites and the Purdue Pegboard. Independent and dependent statistical analyses were employed to compare the rugby versus control group neurocognitive test profiles at and between the three test intervals. Correlational analyses explored the association between concussion, tackling and neurocognitive test outcomes. Descriptive comparisons of individual neurocognitive test scores with normative data were employed for the case analyses. Taken together, the results implicated vulnerability amongst club rugby players on the motor and speeded tasks, with less robust indications on the memory tasks. While limited in terms of its small sample size, it is considered that the outcome of the study was rendered more robust by virtue of being methodologically multifaceted with heuristic implications for future research studies in the area. The novel inclusion of tackling data as well as fine-tuned case analyses, were of particular relevance in that regard. The results add to a growing body of literature that implicates deleterious neurocognitive effects in participants of a sport such as rugby due to repetitive head jarring incidents that are intrinsic to the game.
- Full Text:
- Date Issued: 2015
- Authors: Zoccola, Diana
- Date: 2015
- Subjects: Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3257 , http://hdl.handle.net/10962/d1016397
- Description: The objective of the study was to investigate the cumulative neurocognitive effects of repetitive concussive and subconcussive events in club level Rugby Union (hereafter rugby) during the course of one rugby season, in a combined group and individualized case-based approach. Amateur adult club level rugby players (n = 20) were compared with a non-contact control group (n = 22) of equivalent age, years of education and estimated IQ (p = > .05, in all instances), although the two groups were clearly differentiated on the basis of a history of reported concussions (p = < .05). Video analyses documented the tackling maneuvers observed amongst the players during all matches across the rugby season revealing a sobering average of more than a thousand tackles per player, excluding any contact practice sessions. Five rugby players (n = 5) who were observed to have a head jarring event were also isolated for individualized postconcussive follow-up analysis of their neurocognitive profiles. Measures included the ImPACT Verbal and Visual Memory, Visual Motor Speed and Reaction Time composites and the Purdue Pegboard. Independent and dependent statistical analyses were employed to compare the rugby versus control group neurocognitive test profiles at and between the three test intervals. Correlational analyses explored the association between concussion, tackling and neurocognitive test outcomes. Descriptive comparisons of individual neurocognitive test scores with normative data were employed for the case analyses. Taken together, the results implicated vulnerability amongst club rugby players on the motor and speeded tasks, with less robust indications on the memory tasks. While limited in terms of its small sample size, it is considered that the outcome of the study was rendered more robust by virtue of being methodologically multifaceted with heuristic implications for future research studies in the area. The novel inclusion of tackling data as well as fine-tuned case analyses, were of particular relevance in that regard. The results add to a growing body of literature that implicates deleterious neurocognitive effects in participants of a sport such as rugby due to repetitive head jarring incidents that are intrinsic to the game.
- Full Text:
- Date Issued: 2015
Nonlinear optical studies of phthalocyanines and their conjugates with nanomaterials
- Authors: Sanusi, Sikiru Olukayode
- Date: 2015
- Subjects: Phthalocyanines , Nonlinear optics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4545 , http://hdl.handle.net/10962/d1017925
- Description: A number of metallophthalocyanines (MPcs) and metal-free phthalocyanines (H₂Pcs) have been synthesized and characterized using various characterization tools such as ¹H-NMR, TOF mass spectrometry, FT-IR, UV-visible spectrophotometry and CHNS elemental analysis. Some of the MPcs were covalently linked to nanomaterials such as silica nanoparticles (SiNPs), single-walled carbon nanotubes (SWCNTs), magnetite nanoparticles (MNPs) and quantum dots (QDs), or embedded in polymer thin-films using poly(methyl methacrylate) (PMMA) and poly(acrylic acid) (PAA) as the polymer sources. The phthalocyanine-nanomaterial composites (Pc-NMCs) were characterized with FT-IR, UV-visible spectrophotometry, transmission electron microscopy (TEM), thermogravimetry analysis and X-ray diffractometry. The nonlinear optical (NLO) properties (using the open-aperture Z-scan technique) of the MPcs and the Pc-NMCs were investigated. In general, most of the investigated MPcs showed good optical limiting behaviors, except for a few, like the non-peripherally-substituted 2-pyridyloxy phthalocyanines, which showed inhibited NLO response as a result of the ring-strain effects. The absence of a metal center was found to greatly reduce the inherent high nonlinearities expected of some of the phthalocyanine complexes. The octaphenoxy derivatives (61a – 61e) were found to exhibit reverse saturable absorption (RSA) that depends on the singlet-singlet transitions, hence making them less reliable optical limiters. The optical limiting properties of the MPcs were improved in the presence of nanomaterials such as the QDs, MNPs and SWCNTs, with MPc-QDs showing the best optical limiting behavior of the three. SiNPs have no significant effect on the optical limiting behavior of the MPcs. The optical limiting properties of the MPcs were greatly enhanced in the presence of PMMA or PAA polymers. The PAA polymer showed better optical limiting behavior compared to PMMA
- Full Text:
- Date Issued: 2015
- Authors: Sanusi, Sikiru Olukayode
- Date: 2015
- Subjects: Phthalocyanines , Nonlinear optics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4545 , http://hdl.handle.net/10962/d1017925
- Description: A number of metallophthalocyanines (MPcs) and metal-free phthalocyanines (H₂Pcs) have been synthesized and characterized using various characterization tools such as ¹H-NMR, TOF mass spectrometry, FT-IR, UV-visible spectrophotometry and CHNS elemental analysis. Some of the MPcs were covalently linked to nanomaterials such as silica nanoparticles (SiNPs), single-walled carbon nanotubes (SWCNTs), magnetite nanoparticles (MNPs) and quantum dots (QDs), or embedded in polymer thin-films using poly(methyl methacrylate) (PMMA) and poly(acrylic acid) (PAA) as the polymer sources. The phthalocyanine-nanomaterial composites (Pc-NMCs) were characterized with FT-IR, UV-visible spectrophotometry, transmission electron microscopy (TEM), thermogravimetry analysis and X-ray diffractometry. The nonlinear optical (NLO) properties (using the open-aperture Z-scan technique) of the MPcs and the Pc-NMCs were investigated. In general, most of the investigated MPcs showed good optical limiting behaviors, except for a few, like the non-peripherally-substituted 2-pyridyloxy phthalocyanines, which showed inhibited NLO response as a result of the ring-strain effects. The absence of a metal center was found to greatly reduce the inherent high nonlinearities expected of some of the phthalocyanine complexes. The octaphenoxy derivatives (61a – 61e) were found to exhibit reverse saturable absorption (RSA) that depends on the singlet-singlet transitions, hence making them less reliable optical limiters. The optical limiting properties of the MPcs were improved in the presence of nanomaterials such as the QDs, MNPs and SWCNTs, with MPc-QDs showing the best optical limiting behavior of the three. SiNPs have no significant effect on the optical limiting behavior of the MPcs. The optical limiting properties of the MPcs were greatly enhanced in the presence of PMMA or PAA polymers. The PAA polymer showed better optical limiting behavior compared to PMMA
- Full Text:
- Date Issued: 2015
Performing whiteness; representing otherness : Hugh Tracey and African music
- Authors: Coetzee, Paulette June
- Date: 2015
- Subjects: Tracey, Hugh , Music -- Africa , International Library of African Music , Ethnomusicology -- Africa , Ethnomusicologists -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2327 , http://hdl.handle.net/10962/d1016502
- Description: This thesis provides a critical study of texts associated with Hugh Tracey (1903–1977). Tracey is well-known for his work in African music studies, particularly for his major contribution to the recorded archive of musical sound in sub-Saharan Africa and his founding of the International Library of African Music (ILAM) in 1954. My reading of him is informed by a postcolonial perspective, whiteness studies and African scholarship on ways in which constructions of African identity and tradition have been shaped by the colonial archive. In my view, Tracey was part of a mid-twentieth century movement which sought to marshal positive representations of traditional African culture in the interest of maintaining and strengthening colonial rule. While his recording project may have fostered inclusion through creating spaces for indigenous musicians to be heard, it also functioned to promote racist exclusion in the manner of its production, distribution and claims to expertise. Moreover, his initial strategy for ILAM’s sustainability targeted colonial government and industry as primary clients, with the promise that promoting traditional music as a means of entertainment and self-expression for black subjects and workers would ease administration and reduce conflict. I believe that it is important to acknowledge and interrogate the problematic racial attitudes and practices associated with the history of Tracey’s archive – not to undermine its significance in any way but to allow it to be better understood and used more productively in the future.
- Full Text:
- Date Issued: 2015
- Authors: Coetzee, Paulette June
- Date: 2015
- Subjects: Tracey, Hugh , Music -- Africa , International Library of African Music , Ethnomusicology -- Africa , Ethnomusicologists -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2327 , http://hdl.handle.net/10962/d1016502
- Description: This thesis provides a critical study of texts associated with Hugh Tracey (1903–1977). Tracey is well-known for his work in African music studies, particularly for his major contribution to the recorded archive of musical sound in sub-Saharan Africa and his founding of the International Library of African Music (ILAM) in 1954. My reading of him is informed by a postcolonial perspective, whiteness studies and African scholarship on ways in which constructions of African identity and tradition have been shaped by the colonial archive. In my view, Tracey was part of a mid-twentieth century movement which sought to marshal positive representations of traditional African culture in the interest of maintaining and strengthening colonial rule. While his recording project may have fostered inclusion through creating spaces for indigenous musicians to be heard, it also functioned to promote racist exclusion in the manner of its production, distribution and claims to expertise. Moreover, his initial strategy for ILAM’s sustainability targeted colonial government and industry as primary clients, with the promise that promoting traditional music as a means of entertainment and self-expression for black subjects and workers would ease administration and reduce conflict. I believe that it is important to acknowledge and interrogate the problematic racial attitudes and practices associated with the history of Tracey’s archive – not to undermine its significance in any way but to allow it to be better understood and used more productively in the future.
- Full Text:
- Date Issued: 2015
Photophysical studies of Zinc phthalocyanine-silica nanoparticles conjugates
- Authors: Fashina, Adedayo
- Date: 2015
- Subjects: Nanoparticles , Phthalocyanines , Zinc , Silica , Photochemistry , Adsorption
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4537 , http://hdl.handle.net/10962/d1017917
- Description: This thesis reports on the synthesis and characterization of both symmetrical and asymmetrical Zinc phthalocyanine complexes. The complexes contained groups such as carboxylic, amino and alkyne for covalent grafting to the surface of silica nanoparticles. The use of symmetrical and asymmetrical complexes was geared towards comparing the non-specific binding of the symmetrical complexes to the specific binding observed in the asymmetrical complexes. The complexes were also doped within the silica matrix and compared to the surface grafted conjugates. The complexes and the conjugates were well characterized with a variety of techniques. The fluorescence lifetimes of the phthalocyanine complexes containing either terminal carboxylic groups or an alkyne group showed a mono-exponential decay while the amino containing phthalocyanine complexes gave a bi-exponential decay. A similar trend was observed for their respective conjugates. Some of the conjugates of the asymmetrical complexes showed a decrease in fluorescence lifetimes and a corresponding decrease in fluorescence quantum yields. The fluorescence quantum yields for all the symmetrical complexes studied showed either an improvement or retained the luminescence of the grafted phthalocyanine complex. Most of the conjugates showed a faster intersystem crossing time in comparison to the complexes alone. The grafted or doped conjugates containing symmetrical phthalocyanine complexes with carboxyl groups showed improvements both in fluorescence and triplet quantum yields. All the conjugates except two showed an increase in triplet lifetimes when compared to their respective phthalocyanine complexes. Optical nonlinearities of nine of the phthalocyanine complexes were studied and all the complexes showed characteristic reverse saturable absorption behavior. Complex 10 showed the most promising optical limiting behavior. The aggregation and dissolution studies of the conjugates were also carried out in a simulated biological medium and the silicon level detected was noticed to have increased with incubation time.
- Full Text:
- Date Issued: 2015
- Authors: Fashina, Adedayo
- Date: 2015
- Subjects: Nanoparticles , Phthalocyanines , Zinc , Silica , Photochemistry , Adsorption
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4537 , http://hdl.handle.net/10962/d1017917
- Description: This thesis reports on the synthesis and characterization of both symmetrical and asymmetrical Zinc phthalocyanine complexes. The complexes contained groups such as carboxylic, amino and alkyne for covalent grafting to the surface of silica nanoparticles. The use of symmetrical and asymmetrical complexes was geared towards comparing the non-specific binding of the symmetrical complexes to the specific binding observed in the asymmetrical complexes. The complexes were also doped within the silica matrix and compared to the surface grafted conjugates. The complexes and the conjugates were well characterized with a variety of techniques. The fluorescence lifetimes of the phthalocyanine complexes containing either terminal carboxylic groups or an alkyne group showed a mono-exponential decay while the amino containing phthalocyanine complexes gave a bi-exponential decay. A similar trend was observed for their respective conjugates. Some of the conjugates of the asymmetrical complexes showed a decrease in fluorescence lifetimes and a corresponding decrease in fluorescence quantum yields. The fluorescence quantum yields for all the symmetrical complexes studied showed either an improvement or retained the luminescence of the grafted phthalocyanine complex. Most of the conjugates showed a faster intersystem crossing time in comparison to the complexes alone. The grafted or doped conjugates containing symmetrical phthalocyanine complexes with carboxyl groups showed improvements both in fluorescence and triplet quantum yields. All the conjugates except two showed an increase in triplet lifetimes when compared to their respective phthalocyanine complexes. Optical nonlinearities of nine of the phthalocyanine complexes were studied and all the complexes showed characteristic reverse saturable absorption behavior. Complex 10 showed the most promising optical limiting behavior. The aggregation and dissolution studies of the conjugates were also carried out in a simulated biological medium and the silicon level detected was noticed to have increased with incubation time.
- Full Text:
- Date Issued: 2015
Photophysicochemical properties and in vitro photodynamic therapy activities of zinc phthalocyanine conjugates with biomolecules and single-walled carbon nanotubes
- Authors: Ogbodu, Racheal O
- Date: 2015
- Subjects: Photochemotherapy , Phthalocyanines , Biomolecules
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4544 , http://hdl.handle.net/10962/d1017924
- Description: The synthesis, photophysicochemcial properties, in vitro dark toxicity and photodynamic therapy (PDT) activities of different derivatives of zinc phthalocyanine (ZnPc) conjugates with biomolecules (folic acid, bovine serum albumin (BSA), ascorbic acid, uridine or spermine) and single-walled carbon nanotubes (SWCNTs) are presented in this work. The fluorescence quantum yields (ΦF) (Subscript F) of the ZnPc derivatives or ZnPc-biomolecule conjugates remained relatively the same as compared to the precursor Pcs. Slight increases were observed in the ΦF (Subscript F) values of conjugates containing substituents such as pyrene, folic acid or BSA with intrinsic fluorescence properties. The triplet quantum yield (ΦT ) (Subscript T) values for some ZnPc conjugates increases compared to the precursor ZnPcs due to extended π conjugation (for the conjugate with pyrene) and the presence of phenyl ring that support spin-orbit charge transfer intersystem crossing to triplet state. While some conjugates showed decreases in the ΦT (Subscript T) values compared to precursor ZnPcs due to the presence of substituents that could quench photo-excited state properties. The singlet oxygen quantum yield (ΦΔ ) values follow the trends of the triplet quantum yield values. The conjugates containing BSA also show increases in the ΦΔ values without corresponding increases in ΦT (Subscript T) values due to the ability of BSA to generate free radicals including singlet oxygen. The presence of SWCNTs decreases the photophysicochemcial properties of some ZnPc-SWCNT conjugates compared to the precursor ZnPcs due to photo-induced electron transfer from an excited Pc complex (electron donor) to SWCNTs (electron acceptor). However, increases were observed in some ZnPc-SWCNT conjugates as a result of fast charge recombination process due to highly short-lived radical ion pair produced. These phenomena affected the ΦF (Suscript F) values, ΦT (Suscript T) values, and the ΦΔ values. Increases or decreases in ΦT (Suscript T) values resulted in corresponding increases or decreases in ΦΔ values
- Full Text:
- Date Issued: 2015
- Authors: Ogbodu, Racheal O
- Date: 2015
- Subjects: Photochemotherapy , Phthalocyanines , Biomolecules
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4544 , http://hdl.handle.net/10962/d1017924
- Description: The synthesis, photophysicochemcial properties, in vitro dark toxicity and photodynamic therapy (PDT) activities of different derivatives of zinc phthalocyanine (ZnPc) conjugates with biomolecules (folic acid, bovine serum albumin (BSA), ascorbic acid, uridine or spermine) and single-walled carbon nanotubes (SWCNTs) are presented in this work. The fluorescence quantum yields (ΦF) (Subscript F) of the ZnPc derivatives or ZnPc-biomolecule conjugates remained relatively the same as compared to the precursor Pcs. Slight increases were observed in the ΦF (Subscript F) values of conjugates containing substituents such as pyrene, folic acid or BSA with intrinsic fluorescence properties. The triplet quantum yield (ΦT ) (Subscript T) values for some ZnPc conjugates increases compared to the precursor ZnPcs due to extended π conjugation (for the conjugate with pyrene) and the presence of phenyl ring that support spin-orbit charge transfer intersystem crossing to triplet state. While some conjugates showed decreases in the ΦT (Subscript T) values compared to precursor ZnPcs due to the presence of substituents that could quench photo-excited state properties. The singlet oxygen quantum yield (ΦΔ ) values follow the trends of the triplet quantum yield values. The conjugates containing BSA also show increases in the ΦΔ values without corresponding increases in ΦT (Subscript T) values due to the ability of BSA to generate free radicals including singlet oxygen. The presence of SWCNTs decreases the photophysicochemcial properties of some ZnPc-SWCNT conjugates compared to the precursor ZnPcs due to photo-induced electron transfer from an excited Pc complex (electron donor) to SWCNTs (electron acceptor). However, increases were observed in some ZnPc-SWCNT conjugates as a result of fast charge recombination process due to highly short-lived radical ion pair produced. These phenomena affected the ΦF (Suscript F) values, ΦT (Suscript T) values, and the ΦΔ values. Increases or decreases in ΦT (Suscript T) values resulted in corresponding increases or decreases in ΦΔ values
- Full Text:
- Date Issued: 2015
Phthalocyanine-nanoparticle conjugates for photodynamic therapy of cancer and phototransformation of organic pollutants
- Authors: Khoza, Phindile Brenda
- Date: 2015
- Subjects: Phthalocyanines , Nanoparticles , Photochemotherapy , Cancer -- Chemotherapy , Zinc oxide , Photocatalysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4538 , http://hdl.handle.net/10962/d1017918
- Description: The synthesis and extensive spectroscopical characterization of novel phthalocyanines are reported. The new compounds were characterized by elemental analysis, FT-IR, ¹HNMR, mass spectrometry and UV–Vis spectroscopy. The new phthalocyanines showed remarkable photophysicochemical behaviour. The novel phthalocyanines were then conjugated to nanoparticles, silver and ZnO. The coupling of the novel Pcs to nanoparticles was through covalent bonding and ligand exchange. These conjugates were supported onto electrospun polystyrene fibers and chitosan microbeads for use as photocatalysts. The efficiency of the immobilized Pcs and Pc-nanoparticles was assessed by the phototrasfromation of organic pollutants, methyl orange and Rhodamine 6G as model dyes. Upon conjugating phthalocyanines to nanoparticles, there was a great increase in the rate of photodegradation of the model dyes. The photodynamic activity of the novel phthalocyanines upon conjugating to nanoparticles and selected targeting agents is also reported. The targeting agents employed in this study are folic acid and polylysine. Conjugating the phthalocyanines to folic acid or polylysine improved the solubility of the phthalocyanines in aqueous media. The potency of the conjugates was investigated on breast (MCF-7), prostate and melanoma cancer cell lines. The phthalocyanines showed no toxicity in the absence of light. However, upon illumination, a concentration dependent cellular decrease was observed.
- Full Text:
- Date Issued: 2015
- Authors: Khoza, Phindile Brenda
- Date: 2015
- Subjects: Phthalocyanines , Nanoparticles , Photochemotherapy , Cancer -- Chemotherapy , Zinc oxide , Photocatalysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4538 , http://hdl.handle.net/10962/d1017918
- Description: The synthesis and extensive spectroscopical characterization of novel phthalocyanines are reported. The new compounds were characterized by elemental analysis, FT-IR, ¹HNMR, mass spectrometry and UV–Vis spectroscopy. The new phthalocyanines showed remarkable photophysicochemical behaviour. The novel phthalocyanines were then conjugated to nanoparticles, silver and ZnO. The coupling of the novel Pcs to nanoparticles was through covalent bonding and ligand exchange. These conjugates were supported onto electrospun polystyrene fibers and chitosan microbeads for use as photocatalysts. The efficiency of the immobilized Pcs and Pc-nanoparticles was assessed by the phototrasfromation of organic pollutants, methyl orange and Rhodamine 6G as model dyes. Upon conjugating phthalocyanines to nanoparticles, there was a great increase in the rate of photodegradation of the model dyes. The photodynamic activity of the novel phthalocyanines upon conjugating to nanoparticles and selected targeting agents is also reported. The targeting agents employed in this study are folic acid and polylysine. Conjugating the phthalocyanines to folic acid or polylysine improved the solubility of the phthalocyanines in aqueous media. The potency of the conjugates was investigated on breast (MCF-7), prostate and melanoma cancer cell lines. The phthalocyanines showed no toxicity in the absence of light. However, upon illumination, a concentration dependent cellular decrease was observed.
- Full Text:
- Date Issued: 2015
Pitied plumage and dying birds : the public mourning of national heroines and post-apartheid foundational mythology construction
- Authors: Kerseboom, Simone
- Date: 2015
- Subjects: Women heroes -- South Africa , Nationalism -- South Africa , Nationalism and collective memory -- South Africa , Post-apartheid era -- South Africa , Women political activists -- South Africa , Dead -- Political aspects -- South Africa , Critical discourse analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2625 , http://hdl.handle.net/10962/d1019884
- Description: The original contribution of this thesis is the examination of the official construction of a post-apartheid foundation myth through the analysis of the dead body politics of five iconic South African women that spans the three presidencies that have defined South Africa’s democratic era. This thesis examines the death and funeral of Albertina Sisulu, the return and burial of Sara Baartman, and the commemoration of Charlotte Maxeke, Lilian Ngoyi, and Helen Joseph. Sisulu, Baartman, Maxeke, Ngoyi, and Joseph have been constructed as heroines and as foundational figures for the post-apartheid nation in official rhetoric. It will contend that the dead body politics of these women not only informs a new foundational mythology, but also features in the processes of regime legitimation when the ANC-dominated government faces strong societal criticism. Although such official expressions of nationalism may appear exhausted, this thesis will show that nationalism remains a powerful and dangerous force in South Africa that attempts to silence opposition and critical analysis of perceived failing government policies or inaction. This thesis will indicate that as women’s bodies and legacies are appropriated for nationalist projects they are subsumed in discourses of domestic femininity in official rhetoric that dangerously detract from women’s democratic rights and their ability to exercise responsible and productive citizenship in the post-apartheid state. It will argue that women’s historic political activism is contained within the meta-narrative of ‘The Struggle’ and that women are re-subsumed into the patriarchal discourses of the past that are inherited in the present. This thesis approaches this topic by considering a top-to-bottom construction of post-apartheid nationalism through applying feminist critical discourse analysis to official rhetoric articulated at the public mourning and commemorative rituals of these five women.
- Full Text:
- Date Issued: 2015
- Authors: Kerseboom, Simone
- Date: 2015
- Subjects: Women heroes -- South Africa , Nationalism -- South Africa , Nationalism and collective memory -- South Africa , Post-apartheid era -- South Africa , Women political activists -- South Africa , Dead -- Political aspects -- South Africa , Critical discourse analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2625 , http://hdl.handle.net/10962/d1019884
- Description: The original contribution of this thesis is the examination of the official construction of a post-apartheid foundation myth through the analysis of the dead body politics of five iconic South African women that spans the three presidencies that have defined South Africa’s democratic era. This thesis examines the death and funeral of Albertina Sisulu, the return and burial of Sara Baartman, and the commemoration of Charlotte Maxeke, Lilian Ngoyi, and Helen Joseph. Sisulu, Baartman, Maxeke, Ngoyi, and Joseph have been constructed as heroines and as foundational figures for the post-apartheid nation in official rhetoric. It will contend that the dead body politics of these women not only informs a new foundational mythology, but also features in the processes of regime legitimation when the ANC-dominated government faces strong societal criticism. Although such official expressions of nationalism may appear exhausted, this thesis will show that nationalism remains a powerful and dangerous force in South Africa that attempts to silence opposition and critical analysis of perceived failing government policies or inaction. This thesis will indicate that as women’s bodies and legacies are appropriated for nationalist projects they are subsumed in discourses of domestic femininity in official rhetoric that dangerously detract from women’s democratic rights and their ability to exercise responsible and productive citizenship in the post-apartheid state. It will argue that women’s historic political activism is contained within the meta-narrative of ‘The Struggle’ and that women are re-subsumed into the patriarchal discourses of the past that are inherited in the present. This thesis approaches this topic by considering a top-to-bottom construction of post-apartheid nationalism through applying feminist critical discourse analysis to official rhetoric articulated at the public mourning and commemorative rituals of these five women.
- Full Text:
- Date Issued: 2015
Primary maths teacher learning and identity within a numeracy in-service community of practice
- Authors: Pausigere, Peter
- Date: 2015
- Subjects: Mathematics -- Study and teaching (Elementary) -- South Africa , Teachers -- In-service training -- South Africa , Student-centered learning -- South Africa , Communities of practice -- South Africa , Educational change -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2019 , http://hdl.handle.net/10962/d1017183
- Description: This study focuses on the processes of primary maths teacher learning and how their identities and practices evolve in relation to participation in a primary maths focused in-service teacher education programme, called the Numeracy Inquiry Community of Leader Educators (NICLE).Additionally it investigates activities, relations and forms of participation within the Community of Practice (CoP) which enable or constrain evolving primary maths identities and practices and how these relate to the broader context. The study draws from the situative-participationists (Lave, 1996; Wenger, 1998; Sfard & Prusak, 2005; Wenger et al, 2002) theoretical framework supplemented by Bernstein’s (2000) pedagogic identity model. Using a qualitative educational interpretive approach I sampled 8 primary teachers drawn from NICLE and gathered data through participant observations, interactive interviews, document analysis and reflective journals. Analysing the key data themes that emerged from teacher learning stories, which I have called stelos, the study explains the nature of the primary maths teachers’ learning, transformation and participation experiences in NICLE using the synonyms reinvigoration and remediation and activation and relating these semantics to the teachers’ mathematical identities and histories. The study also explains the processes through which primary maths teacher identities evolve in relation to participation in an in-service CoP as ‘insiding’ and ‘outcropping’. Interpreting qualitative data from the empirical field indicates that teachers participating in NICLE mostly took-up into their maths classrooms key numeracy-domain concepts, resources and issues presented by primary maths experts which are informed by research and theory that link to practices. Teachers collaboratively and actively engaged in a range of activities that relate to classroom practices. Teacher learning was also enabled when teachers engaged in maths overlapping communities of practice, shared classroom experiences in friendly ways with fellow NICLE teachers and engaged with NICLE presenters who mutually respected and regarded them as professionals. Such affordances were said to enable teachers to engage learners in maths classes and improve their understanding of specific primary maths concepts. On the other hand teachers felt challenged by the travelling distance, limited time and also raised the tension of how to scale-up maths professional development initiatives to include schools from their community. The study makes a theoretical contribution by illustrating how Bernstein’s pedagogic identity model and its elaboration by Tyler (1999) provides analytical tools to interrogate macro educational changes and connect these to the micro processes and teacher identities.
- Full Text:
- Date Issued: 2015
- Authors: Pausigere, Peter
- Date: 2015
- Subjects: Mathematics -- Study and teaching (Elementary) -- South Africa , Teachers -- In-service training -- South Africa , Student-centered learning -- South Africa , Communities of practice -- South Africa , Educational change -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2019 , http://hdl.handle.net/10962/d1017183
- Description: This study focuses on the processes of primary maths teacher learning and how their identities and practices evolve in relation to participation in a primary maths focused in-service teacher education programme, called the Numeracy Inquiry Community of Leader Educators (NICLE).Additionally it investigates activities, relations and forms of participation within the Community of Practice (CoP) which enable or constrain evolving primary maths identities and practices and how these relate to the broader context. The study draws from the situative-participationists (Lave, 1996; Wenger, 1998; Sfard & Prusak, 2005; Wenger et al, 2002) theoretical framework supplemented by Bernstein’s (2000) pedagogic identity model. Using a qualitative educational interpretive approach I sampled 8 primary teachers drawn from NICLE and gathered data through participant observations, interactive interviews, document analysis and reflective journals. Analysing the key data themes that emerged from teacher learning stories, which I have called stelos, the study explains the nature of the primary maths teachers’ learning, transformation and participation experiences in NICLE using the synonyms reinvigoration and remediation and activation and relating these semantics to the teachers’ mathematical identities and histories. The study also explains the processes through which primary maths teacher identities evolve in relation to participation in an in-service CoP as ‘insiding’ and ‘outcropping’. Interpreting qualitative data from the empirical field indicates that teachers participating in NICLE mostly took-up into their maths classrooms key numeracy-domain concepts, resources and issues presented by primary maths experts which are informed by research and theory that link to practices. Teachers collaboratively and actively engaged in a range of activities that relate to classroom practices. Teacher learning was also enabled when teachers engaged in maths overlapping communities of practice, shared classroom experiences in friendly ways with fellow NICLE teachers and engaged with NICLE presenters who mutually respected and regarded them as professionals. Such affordances were said to enable teachers to engage learners in maths classes and improve their understanding of specific primary maths concepts. On the other hand teachers felt challenged by the travelling distance, limited time and also raised the tension of how to scale-up maths professional development initiatives to include schools from their community. The study makes a theoretical contribution by illustrating how Bernstein’s pedagogic identity model and its elaboration by Tyler (1999) provides analytical tools to interrogate macro educational changes and connect these to the micro processes and teacher identities.
- Full Text:
- Date Issued: 2015
Pro-active visualization of cyber security on a National Level : a South African case study
- Authors: Swart, Ignatius Petrus
- Date: 2015
- Subjects: Internet -- Security measures -- South Africa , Computer security -- Government policy -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4718 , http://hdl.handle.net/10962/d1017940
- Description: The need for increased national cyber security situational awareness is evident from the growing number of published national cyber security strategies. Governments are progressively seen as responsible for cyber security, but at the same time increasingly constrained by legal, privacy and resource considerations. Infrastructure and services that form part of the national cyber domain are often not under the control of government, necessitating the need for information sharing between governments and commercial partners. While sharing of security information is necessary, it typically requires considerable time to be implemented effectively. In an effort to decrease the time and effort required for cyber security situational awareness, this study considered commercially available data sources relating to a national cyber domain. Open source information is typically used by attackers to gather information with great success. An understanding of the data provided by these sources can also afford decision makers the opportunity to set priorities more effectively. Through the use of an adapted Joint Directors of Laboratories (JDL) fusion model, an experimental system was implemented that visualized the potential that open source intelligence could have on cyber situational awareness. Datasets used in the validation of the model contained information obtained from eight different data sources over a two year period with a focus on the South African .co.za sub domain. Over a million infrastructure devices were examined in this study along with information pertaining to a potential 88 million vulnerabilities on these devices. During the examination of data sources, a severe lack of information regarding the human aspect in cyber security was identified that led to the creation of a novel Personally Identifiable Information detection sensor (PII). The resultant two million records pertaining to PII in the South African domain were incorporated into the data fusion experiment for processing. The results of this processing are discussed in the three case studies. The results offered in this study aim to highlight how data fusion and effective visualization can serve to move national cyber security from a primarily reactive undertaking to a more pro-active model.
- Full Text:
- Date Issued: 2015
- Authors: Swart, Ignatius Petrus
- Date: 2015
- Subjects: Internet -- Security measures -- South Africa , Computer security -- Government policy -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4718 , http://hdl.handle.net/10962/d1017940
- Description: The need for increased national cyber security situational awareness is evident from the growing number of published national cyber security strategies. Governments are progressively seen as responsible for cyber security, but at the same time increasingly constrained by legal, privacy and resource considerations. Infrastructure and services that form part of the national cyber domain are often not under the control of government, necessitating the need for information sharing between governments and commercial partners. While sharing of security information is necessary, it typically requires considerable time to be implemented effectively. In an effort to decrease the time and effort required for cyber security situational awareness, this study considered commercially available data sources relating to a national cyber domain. Open source information is typically used by attackers to gather information with great success. An understanding of the data provided by these sources can also afford decision makers the opportunity to set priorities more effectively. Through the use of an adapted Joint Directors of Laboratories (JDL) fusion model, an experimental system was implemented that visualized the potential that open source intelligence could have on cyber situational awareness. Datasets used in the validation of the model contained information obtained from eight different data sources over a two year period with a focus on the South African .co.za sub domain. Over a million infrastructure devices were examined in this study along with information pertaining to a potential 88 million vulnerabilities on these devices. During the examination of data sources, a severe lack of information regarding the human aspect in cyber security was identified that led to the creation of a novel Personally Identifiable Information detection sensor (PII). The resultant two million records pertaining to PII in the South African domain were incorporated into the data fusion experiment for processing. The results of this processing are discussed in the three case studies. The results offered in this study aim to highlight how data fusion and effective visualization can serve to move national cyber security from a primarily reactive undertaking to a more pro-active model.
- Full Text:
- Date Issued: 2015
Production of Cydia pomonella granulovirus (CpGV) in a heteralogous host, Thaumatotibia Leucotreta (Meyrick) (False codling moth)
- Authors: Chambers, Craig Brian
- Date: 2015
- Subjects: Cryptophlebia leucotreta -- South Africa , Codling moth -- South Africa , Apples -- Diseases and pests -- South Africa , Codling moth -- Biological control -- South Africa , Insect pests -- Biological control -- South Africa , Biological pest control agents -- South Africa , Baculoviruses -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5935 , http://hdl.handle.net/10962/d1017906
- Description: Cydia pomonella (Linnaeus) (Family: Tortricidae), the codling moth, is considered one of the most significant pests of apples and pears worldwide, causing up to 80% crop loss in orchards if no control measures are applied. Cydia pomonella is oligophagous feeding on a number of alternate hosts including quince, walnuts, apricots, peaches, plums and nectarines. Historically the control of this pest has been achieved with the use of various chemical control strategies which have maintained pest levels below the economic threshold at a relatively low cost to the grower. However, there are serious concerns surrounding the use of chemical insecticides including the development of resistance in insect populations, the banning of various insecticides, regulations for lowering of the maximum residue level and employee and consumer safety. For this reason, alternate measures of control are slowly being adopted by growers such as mating disruption, cultural methods and the use of baculovirus biopesticides as part of integrated pest management programmes. The reluctance of growers to accept baculovirus or other biological control products in the past has been due to questionable product quality and inconsistencies in their field performance. Moreover, the development and application of biological control products is more costly than the use of chemical alternatives. Baculoviruses are arthropod specific viruses that are highly virulent to a number of lepidopteran species. Due to the virulence and host specificity of baculoviruses, Cydia pomonella granulovirus has been extensively and successfully used as part of integrated pest management systems for the control of C. pomonella in Europe and around the world, including South Africa. Commercial formulations have been typically based on the Mexican strain of CpGV. However due to long-term multiple applications of CpGV and the reliance on CpGV in organic farming practices in Europe, resistance to the CpGV-M strain has developed in a number of field populations of C. pomonella. This study aimed to identify and characterize novel isolates of CpGV in South Africa and compare their virulence with the commercial standard CpGV-M. Secondly, since C. pomonella is difficult to culture on a large scale, an alternate method of CpGV production was investigated in order to determine if CpGV could be produced more efficiently and at a reduced cost without negatively impacting the quality of the product. Several isolates of CpGV were recovered either from field collected larvae or from a laboratory-reared C. pomonella colony. Characterisation of DNA profiles using a variety of restriction enzymes revealed that only a single isolate, CpGV-SA, was genetically different from the Mexican strain of the virus used in the commercially available CpGV based products in South Africa. In dose-response bioassays using CpGV-SA, LC₅₀ and LC₉₀ values for neonate C. pomonella larvae were 3.18 x 10³ OBs/ml and 7.33 x 10⁴ respectively. A comparison of these values with those of CpGV-M indicated no significant difference in the virulence of the two isolates under laboratory conditions. This is a first report of a genetically distinct CpGV isolate in South Africa. The biological activity and novelty of CpGV-SA makes this isolate a potentially important tool for CpGV resistance management in South Africa. In order to justify production of CpGV in an alternative host, studies on the comparative biological performance of C. pomonella and T. leucotreta based on oviposition, time to hatch, larval developmental times and rearing efficiency as well as production costs were performed. Thaumatotibia leucotreta was found to be more fecund and to have significantly shorter egg and larval developmental times. In addition, larval production per unit of artificial diet was significantly higher than for C. pomonella. This resulted in T. leucotreta being more cost effective to produce with implications for reduced insectary space, sanitation practices as well as the labour component of production. Virus yield data generated by inoculation both C. pomonella and T. leucotreta with nine concentrations of CpGV resulted in comparable virus yields, justifying the continuation of the research into production of CpGV in T. leucotreta. It was important to determine the LC and LT values required for mass production of CpGV in late instar T. leucotreta larvae. Dose- and time-response bioassays with CpGV-M were conducted on artificial diet to determine these values. Fourth instar LC₅₀ and LC₉₀ values were 5.96 x 10³ OBs/ml and 1.64 x 10⁵ OBs/ml respectively. LT50 and LT90 values were 81.10 hours and 88.58 hours respectively. Fifth instar LC₅₀ and LC₉₀ values were 6.88 x 10⁴ OBs/ml and 9.78 x 10⁶ OBs/ml respectively. LT₅₀ and LT₉₀ values were 111.56 hours and 137.57 hours respectively. Virus produced in fourth instar T. leucotreta larvae was bioassayed against C. pomonella neonate larvae and compared to CpGV-M to establish if production in the heterologous host negatively affected the virulence of the isolate. No significant difference in virulence was observed between virus produced in T. leucotreta and that produced in C. pomonella. The data generated in the bioassays was used in CpGV mass production trials to evaluate production. All production methods tested produced acceptable virus yields. To examine the quality of the virus product, genomic DNA was extracted from larval cadavers and subjected to REN analysis with HindIII. The resulting DNA profiles indicated that the virus product was contaminated with the homologous virus, CrleGV. Based on the above results, the use of T. leucotreta as an alternate host for the in vivo production of CpGV on a commercial basis is not at this stage viable and requires further investigation before this production methodology can be reliable used to produce CpGV. However, this study has shown that CpGV can be produced in a homologous host, T. leucotreta and significant strides have been made towards developing a set of quality control standards that are essential for further development of successful production methodology. Finally a novel isolate of CpGV has been identified with comparable virulence to the CpGV-M. This is an important finding as it has broad reaching implications for resistance management of CpGV products in South Africa.
- Full Text:
- Date Issued: 2015
- Authors: Chambers, Craig Brian
- Date: 2015
- Subjects: Cryptophlebia leucotreta -- South Africa , Codling moth -- South Africa , Apples -- Diseases and pests -- South Africa , Codling moth -- Biological control -- South Africa , Insect pests -- Biological control -- South Africa , Biological pest control agents -- South Africa , Baculoviruses -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5935 , http://hdl.handle.net/10962/d1017906
- Description: Cydia pomonella (Linnaeus) (Family: Tortricidae), the codling moth, is considered one of the most significant pests of apples and pears worldwide, causing up to 80% crop loss in orchards if no control measures are applied. Cydia pomonella is oligophagous feeding on a number of alternate hosts including quince, walnuts, apricots, peaches, plums and nectarines. Historically the control of this pest has been achieved with the use of various chemical control strategies which have maintained pest levels below the economic threshold at a relatively low cost to the grower. However, there are serious concerns surrounding the use of chemical insecticides including the development of resistance in insect populations, the banning of various insecticides, regulations for lowering of the maximum residue level and employee and consumer safety. For this reason, alternate measures of control are slowly being adopted by growers such as mating disruption, cultural methods and the use of baculovirus biopesticides as part of integrated pest management programmes. The reluctance of growers to accept baculovirus or other biological control products in the past has been due to questionable product quality and inconsistencies in their field performance. Moreover, the development and application of biological control products is more costly than the use of chemical alternatives. Baculoviruses are arthropod specific viruses that are highly virulent to a number of lepidopteran species. Due to the virulence and host specificity of baculoviruses, Cydia pomonella granulovirus has been extensively and successfully used as part of integrated pest management systems for the control of C. pomonella in Europe and around the world, including South Africa. Commercial formulations have been typically based on the Mexican strain of CpGV. However due to long-term multiple applications of CpGV and the reliance on CpGV in organic farming practices in Europe, resistance to the CpGV-M strain has developed in a number of field populations of C. pomonella. This study aimed to identify and characterize novel isolates of CpGV in South Africa and compare their virulence with the commercial standard CpGV-M. Secondly, since C. pomonella is difficult to culture on a large scale, an alternate method of CpGV production was investigated in order to determine if CpGV could be produced more efficiently and at a reduced cost without negatively impacting the quality of the product. Several isolates of CpGV were recovered either from field collected larvae or from a laboratory-reared C. pomonella colony. Characterisation of DNA profiles using a variety of restriction enzymes revealed that only a single isolate, CpGV-SA, was genetically different from the Mexican strain of the virus used in the commercially available CpGV based products in South Africa. In dose-response bioassays using CpGV-SA, LC₅₀ and LC₉₀ values for neonate C. pomonella larvae were 3.18 x 10³ OBs/ml and 7.33 x 10⁴ respectively. A comparison of these values with those of CpGV-M indicated no significant difference in the virulence of the two isolates under laboratory conditions. This is a first report of a genetically distinct CpGV isolate in South Africa. The biological activity and novelty of CpGV-SA makes this isolate a potentially important tool for CpGV resistance management in South Africa. In order to justify production of CpGV in an alternative host, studies on the comparative biological performance of C. pomonella and T. leucotreta based on oviposition, time to hatch, larval developmental times and rearing efficiency as well as production costs were performed. Thaumatotibia leucotreta was found to be more fecund and to have significantly shorter egg and larval developmental times. In addition, larval production per unit of artificial diet was significantly higher than for C. pomonella. This resulted in T. leucotreta being more cost effective to produce with implications for reduced insectary space, sanitation practices as well as the labour component of production. Virus yield data generated by inoculation both C. pomonella and T. leucotreta with nine concentrations of CpGV resulted in comparable virus yields, justifying the continuation of the research into production of CpGV in T. leucotreta. It was important to determine the LC and LT values required for mass production of CpGV in late instar T. leucotreta larvae. Dose- and time-response bioassays with CpGV-M were conducted on artificial diet to determine these values. Fourth instar LC₅₀ and LC₉₀ values were 5.96 x 10³ OBs/ml and 1.64 x 10⁵ OBs/ml respectively. LT50 and LT90 values were 81.10 hours and 88.58 hours respectively. Fifth instar LC₅₀ and LC₉₀ values were 6.88 x 10⁴ OBs/ml and 9.78 x 10⁶ OBs/ml respectively. LT₅₀ and LT₉₀ values were 111.56 hours and 137.57 hours respectively. Virus produced in fourth instar T. leucotreta larvae was bioassayed against C. pomonella neonate larvae and compared to CpGV-M to establish if production in the heterologous host negatively affected the virulence of the isolate. No significant difference in virulence was observed between virus produced in T. leucotreta and that produced in C. pomonella. The data generated in the bioassays was used in CpGV mass production trials to evaluate production. All production methods tested produced acceptable virus yields. To examine the quality of the virus product, genomic DNA was extracted from larval cadavers and subjected to REN analysis with HindIII. The resulting DNA profiles indicated that the virus product was contaminated with the homologous virus, CrleGV. Based on the above results, the use of T. leucotreta as an alternate host for the in vivo production of CpGV on a commercial basis is not at this stage viable and requires further investigation before this production methodology can be reliable used to produce CpGV. However, this study has shown that CpGV can be produced in a homologous host, T. leucotreta and significant strides have been made towards developing a set of quality control standards that are essential for further development of successful production methodology. Finally a novel isolate of CpGV has been identified with comparable virulence to the CpGV-M. This is an important finding as it has broad reaching implications for resistance management of CpGV products in South Africa.
- Full Text:
- Date Issued: 2015
Re-imagining the nation
- Mngomezulu, Nosipho Sthabiso Thandiwe
- Authors: Mngomezulu, Nosipho Sthabiso Thandiwe
- Date: 2015
- Subjects: Mauritius -- Truth and Justice Commission , Nationalism -- Mauritius , National characteristics, Mauritian , Social justice -- Mauritius , Youth -- Mauritius -- Social conditions , Youth -- Mauritius -- Attitudes , Mauritius -- Politics and government -- 1992- , Ethnicity -- Mauritius
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2124 , http://hdl.handle.net/10962/d1019999
- Description: This thesis examines young people’s constructions of nationhood in Mauritius. In 2008, the Mauritian government instituted a Truth and Justice Commission (TJC), set up to investigate the consequences of slavery and indentured labour. Through the Truth and Justice Commission, the Mauritian government indicated its desire to achieve social justice and national unity. Drawing on developments in studies of national identification practices in the 21st Century, this thesis addresses the question of young Mauritian’s locally and globally informed identification practices and asks how their unofficial narratives of nationhood challenge, or divert, or relate to official state narratives of nationhood. The basis of the study emerges from data collected from 132 participants during fieldwork in multiple fieldsites from May to September 2010 as well as research on Mauritian youth on-line from 2011-2014. The advent of the TJC offers an ideal moment to evaluate the dynamics of post-colonial nation-building and nationhood in a selfstyled multi-cultural state. Nationhood, does not exist apriori to the constructions of narratives of the nation, thus the stories told about the nation, imagine the nation into being. By situating the Truth and Justice Commission and other official state narratives alongside young people’s narratives, I argue that contemporary narratives of nationhood in Mauritius represent an intergenerational struggle to define the meaning of the past in the present and consequently outline the future. Reflecting on the ideas and socio-economic and political processes that induce national consciousness, I argue that young people’s narratives of everyday lived experiences are vital for an interpretation of how nationhood is produced in everyday life. The cultural projects of young people – often rendered as liminal or marginal – offer a critical vantage point from where to read constructions of nationhood. Far from being growing pains or childish games, young people’s identity making practices are what Sherry B. Ortner has called “serious games.” This research suggests that official state government narratives of multicultural nationhood in Mauritius narrowly define national identification along communal loyalties, overlooking the dynamism of interculturality and transnationalism in daily practice on the island. Although communalism and rigid colonial interpretations of ethnicity attempt to police and limit the possibilities of alternative modes of being in Mauritius, young people’s identification practices question, challenge, and threaten to disrupt official discourses of ethnic identification in Mauritius Scholarly investigations of young peoples’ lived experiences of nationhood extend theoretical and methodological frames for the study of nationalized subjects and deepen the understanding of the construction of national consciousness. The construction of nationhood always involves narratives of some sort – scholarship on this area has usually focused on official state narratives from social theorists, state governments, and state elites. I argue for the importance of considering subjectivity and lived experience in conceptions of nationhood. In contemporary post-colonial societies, young people are the numerical majority, however, their voices are seldom represented in theories and narratives of nationhood. Whilst young people may appear in state policies (especially education) and official narratives about the future of the nation, their creative imagining and reimagining of narratives of selfhood is often ignored. I examine how young people increasingly are aware of their transnational connections, through participation in transnational youth cultures, and they are consequently increasingly multi-lingual and multicultural. Fixed notions of ethnic identification and discourses of trauma are not at the forefront of young people’s identification of selfhood, rather their ability to take advantage of their multiply situated identification processes allows them new means to evade and transform these narratives. Their identification of selfhood is characterised by a greater degree of dynamism than previous generations had access to, and thus they do not only identify themselves through officially sanctioned national forms of identification. Loyalty to nationhood is thus less predictable, and young people represent a potential threat to the continuation of older forms of nationhood. While official narratives of nationhood may manipulate ethnic and racial cleavages to secure old loyalties, not all young people are persuaded by these notions
- Full Text:
- Date Issued: 2015
- Authors: Mngomezulu, Nosipho Sthabiso Thandiwe
- Date: 2015
- Subjects: Mauritius -- Truth and Justice Commission , Nationalism -- Mauritius , National characteristics, Mauritian , Social justice -- Mauritius , Youth -- Mauritius -- Social conditions , Youth -- Mauritius -- Attitudes , Mauritius -- Politics and government -- 1992- , Ethnicity -- Mauritius
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2124 , http://hdl.handle.net/10962/d1019999
- Description: This thesis examines young people’s constructions of nationhood in Mauritius. In 2008, the Mauritian government instituted a Truth and Justice Commission (TJC), set up to investigate the consequences of slavery and indentured labour. Through the Truth and Justice Commission, the Mauritian government indicated its desire to achieve social justice and national unity. Drawing on developments in studies of national identification practices in the 21st Century, this thesis addresses the question of young Mauritian’s locally and globally informed identification practices and asks how their unofficial narratives of nationhood challenge, or divert, or relate to official state narratives of nationhood. The basis of the study emerges from data collected from 132 participants during fieldwork in multiple fieldsites from May to September 2010 as well as research on Mauritian youth on-line from 2011-2014. The advent of the TJC offers an ideal moment to evaluate the dynamics of post-colonial nation-building and nationhood in a selfstyled multi-cultural state. Nationhood, does not exist apriori to the constructions of narratives of the nation, thus the stories told about the nation, imagine the nation into being. By situating the Truth and Justice Commission and other official state narratives alongside young people’s narratives, I argue that contemporary narratives of nationhood in Mauritius represent an intergenerational struggle to define the meaning of the past in the present and consequently outline the future. Reflecting on the ideas and socio-economic and political processes that induce national consciousness, I argue that young people’s narratives of everyday lived experiences are vital for an interpretation of how nationhood is produced in everyday life. The cultural projects of young people – often rendered as liminal or marginal – offer a critical vantage point from where to read constructions of nationhood. Far from being growing pains or childish games, young people’s identity making practices are what Sherry B. Ortner has called “serious games.” This research suggests that official state government narratives of multicultural nationhood in Mauritius narrowly define national identification along communal loyalties, overlooking the dynamism of interculturality and transnationalism in daily practice on the island. Although communalism and rigid colonial interpretations of ethnicity attempt to police and limit the possibilities of alternative modes of being in Mauritius, young people’s identification practices question, challenge, and threaten to disrupt official discourses of ethnic identification in Mauritius Scholarly investigations of young peoples’ lived experiences of nationhood extend theoretical and methodological frames for the study of nationalized subjects and deepen the understanding of the construction of national consciousness. The construction of nationhood always involves narratives of some sort – scholarship on this area has usually focused on official state narratives from social theorists, state governments, and state elites. I argue for the importance of considering subjectivity and lived experience in conceptions of nationhood. In contemporary post-colonial societies, young people are the numerical majority, however, their voices are seldom represented in theories and narratives of nationhood. Whilst young people may appear in state policies (especially education) and official narratives about the future of the nation, their creative imagining and reimagining of narratives of selfhood is often ignored. I examine how young people increasingly are aware of their transnational connections, through participation in transnational youth cultures, and they are consequently increasingly multi-lingual and multicultural. Fixed notions of ethnic identification and discourses of trauma are not at the forefront of young people’s identification of selfhood, rather their ability to take advantage of their multiply situated identification processes allows them new means to evade and transform these narratives. Their identification of selfhood is characterised by a greater degree of dynamism than previous generations had access to, and thus they do not only identify themselves through officially sanctioned national forms of identification. Loyalty to nationhood is thus less predictable, and young people represent a potential threat to the continuation of older forms of nationhood. While official narratives of nationhood may manipulate ethnic and racial cleavages to secure old loyalties, not all young people are persuaded by these notions
- Full Text:
- Date Issued: 2015
Reading identities: a case study of grade 8 learners' interactions in a reading club
- Scheckle, Eileen Margaret Agnes
- Authors: Scheckle, Eileen Margaret Agnes
- Date: 2015
- Subjects: Group reading -- South Africa , Reading (Middle school) -- South Africa , Literacy programs -- South Africa , Identity (Psychology) in adolescence , Identity (Psychology) in adolescence -- South Africa , Discourse analysis -- Social aspects , Critical realism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1329 , http://hdl.handle.net/10962/d1017766
- Description: This study offers an account of reading clubs as a literacy intervention in a grade 8 English class at a former ‘Coloured’ high school in South Africa. Using Margaret Archer’s social realist methodology, it examines different practices of ‘reading’ used by learners in talking and writing about text. Archer’s analytical dualism and morphogenetic model provided an explanatory framework for this study. Analytical dualism allows for the separation of the parts (structural and cultural elements) from the people (the grade 8 learners) so as to analyse the interplay between structure and culture. The morphogenetic model recognises that antecedent structures predate this, and any study but that through the exercise of agency, morphogenesis, in the form of structural elaboration or morphostasis in the form of continuity, may occur. This study used a New Literacies perspective based on an ideological model of literacy which recognises many different literacies, in addition to dominant school literacies. Learners’ talk about books as well as personal journal writing provided an insight into what cultural mechanisms and powers children bring to the reading of novels. Understandings of discourses as well as of Gee’s (1990; 2008) construct of Discourse provided a framework for examining learners’ identities and shifts as readers. The data in this study, which is presented through a series of vignettes, found that grade 8 learners use many different experiences and draw on different discourses when making sense of texts. Through the separation of the structural and cultural components, this research could explore how reading clubs as structures enabled learners to access different discourses from the domain of culture. Through the process and engagement in the reading clubs, following Gee (2000b), learners were attributed affinity, discoursal and institutional identities as readers. It was found, in the course of the study, that providing a safe space, scaffolding, multiple opportunities to practice and a variety of reading material, helped learners to access and appropriate dominant literacies. In addition, learners need a repertoire of literacy practices to draw from as successful reading needs flexibility and adaptability. Reading and writing inform each other and through gradual induction into literary writing, learners began to appropriate and approximate dominant literacy practices. Following others who have contributed to the field of New Literacy Studies (Heath, 1983; Street, 1984; Gee 1990; Prinsloo & Breier, 1996), this study would suggest that literacies of traditionally underserved communities should not be considered in deficit terms. Instead these need to be understood as resources for negotiating meaning making and as tools or mechanisms to access dominant discourse practices. In addition the resilience and competition from Discourses of popular culture need to be recognised and developed as tools to access school literacies.
- Full Text:
- Date Issued: 2015
- Authors: Scheckle, Eileen Margaret Agnes
- Date: 2015
- Subjects: Group reading -- South Africa , Reading (Middle school) -- South Africa , Literacy programs -- South Africa , Identity (Psychology) in adolescence , Identity (Psychology) in adolescence -- South Africa , Discourse analysis -- Social aspects , Critical realism
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1329 , http://hdl.handle.net/10962/d1017766
- Description: This study offers an account of reading clubs as a literacy intervention in a grade 8 English class at a former ‘Coloured’ high school in South Africa. Using Margaret Archer’s social realist methodology, it examines different practices of ‘reading’ used by learners in talking and writing about text. Archer’s analytical dualism and morphogenetic model provided an explanatory framework for this study. Analytical dualism allows for the separation of the parts (structural and cultural elements) from the people (the grade 8 learners) so as to analyse the interplay between structure and culture. The morphogenetic model recognises that antecedent structures predate this, and any study but that through the exercise of agency, morphogenesis, in the form of structural elaboration or morphostasis in the form of continuity, may occur. This study used a New Literacies perspective based on an ideological model of literacy which recognises many different literacies, in addition to dominant school literacies. Learners’ talk about books as well as personal journal writing provided an insight into what cultural mechanisms and powers children bring to the reading of novels. Understandings of discourses as well as of Gee’s (1990; 2008) construct of Discourse provided a framework for examining learners’ identities and shifts as readers. The data in this study, which is presented through a series of vignettes, found that grade 8 learners use many different experiences and draw on different discourses when making sense of texts. Through the separation of the structural and cultural components, this research could explore how reading clubs as structures enabled learners to access different discourses from the domain of culture. Through the process and engagement in the reading clubs, following Gee (2000b), learners were attributed affinity, discoursal and institutional identities as readers. It was found, in the course of the study, that providing a safe space, scaffolding, multiple opportunities to practice and a variety of reading material, helped learners to access and appropriate dominant literacies. In addition, learners need a repertoire of literacy practices to draw from as successful reading needs flexibility and adaptability. Reading and writing inform each other and through gradual induction into literary writing, learners began to appropriate and approximate dominant literacy practices. Following others who have contributed to the field of New Literacy Studies (Heath, 1983; Street, 1984; Gee 1990; Prinsloo & Breier, 1996), this study would suggest that literacies of traditionally underserved communities should not be considered in deficit terms. Instead these need to be understood as resources for negotiating meaning making and as tools or mechanisms to access dominant discourse practices. In addition the resilience and competition from Discourses of popular culture need to be recognised and developed as tools to access school literacies.
- Full Text:
- Date Issued: 2015
Saving the Sowetan : the public interest and commercial imperatives in journalism practice
- Authors: Cowling, Lesley
- Date: 2015
- Subjects: Sowetan (Johannesburg, South Africa) , Journalism -- Economic aspects -- South Africa -- Soweto , Journalism -- Political aspects -- South Africa -- Soweto , Black newspapers -- South Africa -- Soweto , Public interest -- South Africa -- Soweto , Corporate culture -- South Africa -- Soweto , Journalistic ethics -- South Africa -- Soweto , Journalism -- Objectivity -- South Africa -- Soweto
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3540 , http://hdl.handle.net/10962/d1017781
- Description: This thesis examines the complex ways in which notions of the public interest and commercial imperatives intertwine in journalism practice. It does this through a study of the 2004 takeover and relaunch of the Sowetan newspaper, the highest circulation daily in South Africa throughout the 1990s and an institution of black public life. The ‘public interest’ and ‘the commercial’ are recurring ideas in journalism scholarship and practice, and the relaunch appeared to be a challenge to reconcile the Sowetan’s commercial challenges with its historical responsibility to a ‘nation-building’ public. However, the research shows that the public/commercial aspects of journalism were inextricably entangled with Sowetan’s organisational culture, which was the matrix through which its journalism practice was expressed. Conflict in the organisation over the changes was not simply a contest between commercial realities and the public interest, with journalists defending a responsibility to the public and managers pushing commercial solutions, but a conflict between the culture of Sowetan “insiders”, steeped in the legacy of the newspaper, and “outsiders”, employed by the new owners to effect change. Another conclusion of the research is that commercial “realities” – often conceptualised as counter to the public interest – are highly mutable. Basic conditions, such as a dependence on advertising, exist. However, media managers must choose from a range of strategies to be commercially viable, which requires risk-taking, innovation and, often, guesswork. In such situations, the ‘wall’ between media managers and senior editors is porous, as all executives must manage the relationship between business and editorial imperatives. Executives tend to overlook culture as a factor in changing organisations, but I argue that journalism could benefit from engaging with management theory and organisational psychology, which offer ways to understand the specific dynamics of the organisation. Finally, I argue that the case of the Sowetan throws into question the idea that there may be a broadly universal journalism culture. The attachment of Sowetan journalists to their particular values and practice suggests that forms of journalism evolve in certain contexts to diverge from the ‘professional’ Anglo-American modes. These ‘journalisms’ use similar terms – such as the ‘public interest’ – but operationalise them quite differently. The responsibility to the public is imagined in very different ways, but remains a significant attachment for journalists.
- Full Text:
- Date Issued: 2015
- Authors: Cowling, Lesley
- Date: 2015
- Subjects: Sowetan (Johannesburg, South Africa) , Journalism -- Economic aspects -- South Africa -- Soweto , Journalism -- Political aspects -- South Africa -- Soweto , Black newspapers -- South Africa -- Soweto , Public interest -- South Africa -- Soweto , Corporate culture -- South Africa -- Soweto , Journalistic ethics -- South Africa -- Soweto , Journalism -- Objectivity -- South Africa -- Soweto
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3540 , http://hdl.handle.net/10962/d1017781
- Description: This thesis examines the complex ways in which notions of the public interest and commercial imperatives intertwine in journalism practice. It does this through a study of the 2004 takeover and relaunch of the Sowetan newspaper, the highest circulation daily in South Africa throughout the 1990s and an institution of black public life. The ‘public interest’ and ‘the commercial’ are recurring ideas in journalism scholarship and practice, and the relaunch appeared to be a challenge to reconcile the Sowetan’s commercial challenges with its historical responsibility to a ‘nation-building’ public. However, the research shows that the public/commercial aspects of journalism were inextricably entangled with Sowetan’s organisational culture, which was the matrix through which its journalism practice was expressed. Conflict in the organisation over the changes was not simply a contest between commercial realities and the public interest, with journalists defending a responsibility to the public and managers pushing commercial solutions, but a conflict between the culture of Sowetan “insiders”, steeped in the legacy of the newspaper, and “outsiders”, employed by the new owners to effect change. Another conclusion of the research is that commercial “realities” – often conceptualised as counter to the public interest – are highly mutable. Basic conditions, such as a dependence on advertising, exist. However, media managers must choose from a range of strategies to be commercially viable, which requires risk-taking, innovation and, often, guesswork. In such situations, the ‘wall’ between media managers and senior editors is porous, as all executives must manage the relationship between business and editorial imperatives. Executives tend to overlook culture as a factor in changing organisations, but I argue that journalism could benefit from engaging with management theory and organisational psychology, which offer ways to understand the specific dynamics of the organisation. Finally, I argue that the case of the Sowetan throws into question the idea that there may be a broadly universal journalism culture. The attachment of Sowetan journalists to their particular values and practice suggests that forms of journalism evolve in certain contexts to diverge from the ‘professional’ Anglo-American modes. These ‘journalisms’ use similar terms – such as the ‘public interest’ – but operationalise them quite differently. The responsibility to the public is imagined in very different ways, but remains a significant attachment for journalists.
- Full Text:
- Date Issued: 2015