Composite polyester membranes with embedded dendrimer hosts and bimetallic Fe/Ni nanoparticles: synthesis, characterisation and application to water treatment
- Malinga, S P, Arotiba, O A, Mapolie, S F, Krause, Rui W M, Mamba, Bhekie B, Diallo, M S
- Authors: Malinga, S P , Arotiba, O A , Mapolie, S F , Krause, Rui W M , Mamba, Bhekie B , Diallo, M S
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125086 , vital:35727 , https://doi.org/10.1007/s11051-013-1698-y
- Description: This study describes the preparation, characterization and evaluation of new composite membranes with embedded dendrimer hosts and Fe/Ni nanoparticles. These new reactive membranes consist of films of cyclodextrin–poly(propyleneimine) dendrimers (β-CD–PPI) that are deposited onto commercial polysulfone microporous supports and crosslinked with trimesoyl chloride (TMC). The membranes were subsequently loaded with Fe/Ni nanoparticles and evaluated as separation/reactive media in aqueous solutions using 2,4,6-trichlorophenol as model pollutant. The morphology and physicochemical properties of the composite membranes were characterised using high-resolution transmission electron microscopy (HR-TEM), atomic force microscopy and measurements of contact angle, water intake, porosity and water permeability. The sorption capacity and catalytic activity of the membranes were evaluated using ion chromatography, atmospheric pressure chemical ionisation-mass spectrometry and UV–Vis spectroscopy (UV–Vis). The sizes of the embedded Fe/Ni nanoparticles in the membranes ranged from 40 to 66 nm as confirmed by HR-TEM. The reaction rates for the dechlorination of 2,4,6-trichlorophenol ranged from 0.00148 to 0.00250 min−1. In all cases, we found that the reaction by-products consisted of chloride ions and mixtures of compounds including phenol (m/z = 93), 2,4-dichlorophenol (m/z = 163) and 4-chlorophenol (m/z = 128). The overall results of this study suggest that β-CD–PPI dendrimers are promising building blocks for the synthesis of composite and reactive membranes for the efficient removal of chlorinated organic pollutants from water.
- Full Text:
- Authors: Malinga, S P , Arotiba, O A , Mapolie, S F , Krause, Rui W M , Mamba, Bhekie B , Diallo, M S
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125086 , vital:35727 , https://doi.org/10.1007/s11051-013-1698-y
- Description: This study describes the preparation, characterization and evaluation of new composite membranes with embedded dendrimer hosts and Fe/Ni nanoparticles. These new reactive membranes consist of films of cyclodextrin–poly(propyleneimine) dendrimers (β-CD–PPI) that are deposited onto commercial polysulfone microporous supports and crosslinked with trimesoyl chloride (TMC). The membranes were subsequently loaded with Fe/Ni nanoparticles and evaluated as separation/reactive media in aqueous solutions using 2,4,6-trichlorophenol as model pollutant. The morphology and physicochemical properties of the composite membranes were characterised using high-resolution transmission electron microscopy (HR-TEM), atomic force microscopy and measurements of contact angle, water intake, porosity and water permeability. The sorption capacity and catalytic activity of the membranes were evaluated using ion chromatography, atmospheric pressure chemical ionisation-mass spectrometry and UV–Vis spectroscopy (UV–Vis). The sizes of the embedded Fe/Ni nanoparticles in the membranes ranged from 40 to 66 nm as confirmed by HR-TEM. The reaction rates for the dechlorination of 2,4,6-trichlorophenol ranged from 0.00148 to 0.00250 min−1. In all cases, we found that the reaction by-products consisted of chloride ions and mixtures of compounds including phenol (m/z = 93), 2,4-dichlorophenol (m/z = 163) and 4-chlorophenol (m/z = 128). The overall results of this study suggest that β-CD–PPI dendrimers are promising building blocks for the synthesis of composite and reactive membranes for the efficient removal of chlorinated organic pollutants from water.
- Full Text:
Computational thinking in educational activities: an evaluation of the educational game light-bot
- Gouws, Lindsey Ann, Bradshaw, Karen L
- Authors: Gouws, Lindsey Ann , Bradshaw, Karen L
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/477581 , vital:78101 , ISBN 9781450320788 , https://doi.org/10.1145/2462476.2466518
- Description: Computational thinking is gaining recognition as an important skill set for students, both in computer science and other disciplines. Although there has been much focus on this field in recent years, it is rarely taught as a formal course within the curriculum, and there is little consensus on what exactly computational thinking entails and how to teach and evaluate it. To address these concerns, we have developed a computational thinking framework to be used as a planning and evaluative tool. Within this framework, we aim to unify the differing opinions about what computational thinking should involve. As a case study, we have applied the framework to Light-Bot, an educational game with a strong focus on programming, and found that the framework provides us with insight into the usefulness of the game to reinforce computer science concepts.
- Full Text:
- Authors: Gouws, Lindsey Ann , Bradshaw, Karen L
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/477581 , vital:78101 , ISBN 9781450320788 , https://doi.org/10.1145/2462476.2466518
- Description: Computational thinking is gaining recognition as an important skill set for students, both in computer science and other disciplines. Although there has been much focus on this field in recent years, it is rarely taught as a formal course within the curriculum, and there is little consensus on what exactly computational thinking entails and how to teach and evaluate it. To address these concerns, we have developed a computational thinking framework to be used as a planning and evaluative tool. Within this framework, we aim to unify the differing opinions about what computational thinking should involve. As a case study, we have applied the framework to Light-Bot, an educational game with a strong focus on programming, and found that the framework provides us with insight into the usefulness of the game to reinforce computer science concepts.
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Consistencies far beyond chance: an analysis of learner preconceptions of reflective symmetry
- Mhlolo, Michael K, Schäfer, Marc
- Authors: Mhlolo, Michael K , Schäfer, Marc
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141139 , vital:37947 , DOI: 10.15700/saje.v33n2a686
- Description: This article reports on regularities observed in learners’ preconceptions of reflective symmetry. Literature suggests that the very existence of such regularities indicates a gap between what learners know and what they need to know. Such a gap inhibits further understanding and application, and hence needed to be investigated. A total of 235 Grade 11 learners, from 13 high schools that participate in the First Rand Foundation-funded Mathematics Education project in the Eastern Cape, responded to a task on reflective symmetry. Our framework for analysing the responses was based on the taxonomy of structure of the observed learning outcome. The results indicated that 85% of learner responses reflect a motion understanding of reflections, where learners considered geometric figures as physical motions on top of the plane. While this understanding is useful in some cases, it is not an essential aspect of mapping understanding, which is critical for application in function notations and other analytical geometry contexts. We suggest that if this gap is to be closed, learners need to construct these reflections physically so that they may think of reflections beyond motion.
- Full Text:
- Authors: Mhlolo, Michael K , Schäfer, Marc
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141139 , vital:37947 , DOI: 10.15700/saje.v33n2a686
- Description: This article reports on regularities observed in learners’ preconceptions of reflective symmetry. Literature suggests that the very existence of such regularities indicates a gap between what learners know and what they need to know. Such a gap inhibits further understanding and application, and hence needed to be investigated. A total of 235 Grade 11 learners, from 13 high schools that participate in the First Rand Foundation-funded Mathematics Education project in the Eastern Cape, responded to a task on reflective symmetry. Our framework for analysing the responses was based on the taxonomy of structure of the observed learning outcome. The results indicated that 85% of learner responses reflect a motion understanding of reflections, where learners considered geometric figures as physical motions on top of the plane. While this understanding is useful in some cases, it is not an essential aspect of mapping understanding, which is critical for application in function notations and other analytical geometry contexts. We suggest that if this gap is to be closed, learners need to construct these reflections physically so that they may think of reflections beyond motion.
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Constructions of nationhood in secession debates related to Mthwakazi Liberation Front in Bulawayo's Chronicle and Newsday newspapers in 2011
- Authors: Ndlovu, Mphathisi
- Date: 2013
- Subjects: Newspapers , Bulawayo , Matabeleland , Zimbabwe , Chronicle , Newsday , Secession , Devolution , Nationhood , Ndebele , Ethnic identity , Mthwakazi Liberation Front , Mthwakazi Liberation Front -- Zimbabwe , Mass media and nationalism -- Research -- Zimbabwe , Bulawayo (Zimbabwe) -- Newspapers , Matabeleland (Zimbabwe) -- History -- Autonomy and independence movements , Matabeleland (Zimbabwe) -- Social conditions , Zimbabwe -- Social conditions
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3415 , http://hdl.handle.net/10962/d1001846
- Description: This study investigates the constructions of nationhood in two Bulawayo newspapers, the Chronicle and Newsday. Against the backdrop of the emergence of a secessionist movement, Mthwakazi Liberation Front (MLF), this research examines the discourses of nationhood in the secessionist debates raging in these two newspapers. This study is premised on a view that nationhood constructions cannot be understood outside the broader context in which these newspapers are embedded. Accordingly, it traces the roots and resurgence of Matabeleland separatist politics, exploring the political-historical forces that have shaped a distinctive Ndebele identity that poses a threat to the one, indivisible Zimbabwean national identity. Further, the study situates Matabeleland separatist politics within the broader African secessionist discourse challenging the post-colonial nation-building project on the continent. Informed by Hall’s (1992, 1996) constructivist approach to identity, it considers national identities as fragmented, multiple and constantly evolving. Thus, this study is framed within Hall’s (1997) constructivist approach to representation, as it examines the constructions of nationhood in and through language. The study uses qualitative research methods, as it examines the meanings of nationhood in key media texts. Informed by Foucault’s discourse theory, this research employs critical discourse analysis (CDA) to analyse 12 articles from the two newspapers. The findings confirm that the representations of nationhood in the two newspapers are influenced by their position within the socio-political context. The state-owned Chronicle legitimates the unitary state discourse advocated by ZANU PF. On the other hand, Newsday’s representations are informed by the discourses of the opposition political parties and civil society that challenge the dominant nation-building project. Thus, within this paper, secession and devolution emerge as alternative imaginaries that contest the authoritarian discourse of nationhood
- Full Text:
- Authors: Ndlovu, Mphathisi
- Date: 2013
- Subjects: Newspapers , Bulawayo , Matabeleland , Zimbabwe , Chronicle , Newsday , Secession , Devolution , Nationhood , Ndebele , Ethnic identity , Mthwakazi Liberation Front , Mthwakazi Liberation Front -- Zimbabwe , Mass media and nationalism -- Research -- Zimbabwe , Bulawayo (Zimbabwe) -- Newspapers , Matabeleland (Zimbabwe) -- History -- Autonomy and independence movements , Matabeleland (Zimbabwe) -- Social conditions , Zimbabwe -- Social conditions
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:3415 , http://hdl.handle.net/10962/d1001846
- Description: This study investigates the constructions of nationhood in two Bulawayo newspapers, the Chronicle and Newsday. Against the backdrop of the emergence of a secessionist movement, Mthwakazi Liberation Front (MLF), this research examines the discourses of nationhood in the secessionist debates raging in these two newspapers. This study is premised on a view that nationhood constructions cannot be understood outside the broader context in which these newspapers are embedded. Accordingly, it traces the roots and resurgence of Matabeleland separatist politics, exploring the political-historical forces that have shaped a distinctive Ndebele identity that poses a threat to the one, indivisible Zimbabwean national identity. Further, the study situates Matabeleland separatist politics within the broader African secessionist discourse challenging the post-colonial nation-building project on the continent. Informed by Hall’s (1992, 1996) constructivist approach to identity, it considers national identities as fragmented, multiple and constantly evolving. Thus, this study is framed within Hall’s (1997) constructivist approach to representation, as it examines the constructions of nationhood in and through language. The study uses qualitative research methods, as it examines the meanings of nationhood in key media texts. Informed by Foucault’s discourse theory, this research employs critical discourse analysis (CDA) to analyse 12 articles from the two newspapers. The findings confirm that the representations of nationhood in the two newspapers are influenced by their position within the socio-political context. The state-owned Chronicle legitimates the unitary state discourse advocated by ZANU PF. On the other hand, Newsday’s representations are informed by the discourses of the opposition political parties and civil society that challenge the dominant nation-building project. Thus, within this paper, secession and devolution emerge as alternative imaginaries that contest the authoritarian discourse of nationhood
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Contributions of inshore and offshore sources of primary production to the foodweb, and the trophic connectivity between various habitats along a depth-gradient, in Sodwana Bay, Kwazulu-Natal, South Africa
- Authors: Parkinson, Matthew Cameron
- Date: 2013
- Subjects: Marine ecology -- South Africa -- Sodwana Bay , Food chains (Ecology) -- South Africa -- Sodwana Bay , Coastal ecology -- South Africa -- Sodwana Bay , Stable isotopes , Dinoflagellates , Marine algae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5179 , http://hdl.handle.net/10962/d1001630 , Marine ecology -- South Africa -- Sodwana Bay , Food chains (Ecology) -- South Africa -- Sodwana Bay , Coastal ecology -- South Africa -- Sodwana Bay , Stable isotopes , Dinoflagellates , Marine algae
- Description: Sodwana Bay, situated within the iSimangaliso Wetland Park, is ecologically important as it contains high-latitude corals and the most southerly known population of coelacanths. This thesis utilised stable isotope and lipid analyses to investigate the trophic ecology of the area, in particular, understanding the relative contribution of inshore and offshore primary production to consumers inhabiting intertidal and shallow subtidal, coral reef, deep reef, canyon head and pelagic habitats. Seaweeds, excluding certain species of red seaweeds with highly depleted carbon signatures, and phytoplankton, such as diatoms, were found to be the principal sources of primary production for all consumers. Offshore production was typified by dinoflagellates. Particulate organic matter (POM) was spatio-temporally variable. Three distinct productivity periods related to nutrient cycling were noted with enriched carbon signatures and higher organic matter loads associated with warmer water. Inshore primary production was an important source of carbon to consumers in all habitats with the exception of zooplankton that were more reliant on pelagic primary production. Benthic invertebrates reflected a gradient in the utilisation of inshore production, due to the reduced availability of this source further offshore. Consumers at the furthest sites offshore were found to include a substantial quantity of inshore-derived production in their diets. Fishes, which are more mobile, were found to incorporate a similar proportion of inshore production into their diets regardless of where they were collected from.
- Full Text:
- Authors: Parkinson, Matthew Cameron
- Date: 2013
- Subjects: Marine ecology -- South Africa -- Sodwana Bay , Food chains (Ecology) -- South Africa -- Sodwana Bay , Coastal ecology -- South Africa -- Sodwana Bay , Stable isotopes , Dinoflagellates , Marine algae
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5179 , http://hdl.handle.net/10962/d1001630 , Marine ecology -- South Africa -- Sodwana Bay , Food chains (Ecology) -- South Africa -- Sodwana Bay , Coastal ecology -- South Africa -- Sodwana Bay , Stable isotopes , Dinoflagellates , Marine algae
- Description: Sodwana Bay, situated within the iSimangaliso Wetland Park, is ecologically important as it contains high-latitude corals and the most southerly known population of coelacanths. This thesis utilised stable isotope and lipid analyses to investigate the trophic ecology of the area, in particular, understanding the relative contribution of inshore and offshore primary production to consumers inhabiting intertidal and shallow subtidal, coral reef, deep reef, canyon head and pelagic habitats. Seaweeds, excluding certain species of red seaweeds with highly depleted carbon signatures, and phytoplankton, such as diatoms, were found to be the principal sources of primary production for all consumers. Offshore production was typified by dinoflagellates. Particulate organic matter (POM) was spatio-temporally variable. Three distinct productivity periods related to nutrient cycling were noted with enriched carbon signatures and higher organic matter loads associated with warmer water. Inshore primary production was an important source of carbon to consumers in all habitats with the exception of zooplankton that were more reliant on pelagic primary production. Benthic invertebrates reflected a gradient in the utilisation of inshore production, due to the reduced availability of this source further offshore. Consumers at the furthest sites offshore were found to include a substantial quantity of inshore-derived production in their diets. Fishes, which are more mobile, were found to incorporate a similar proportion of inshore production into their diets regardless of where they were collected from.
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Control protocol command translation for device interoperability on ethernet AVB networks
- Foss, Richard, Igumbor, Osedum P
- Authors: Foss, Richard , Igumbor, Osedum P
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426978 , vital:72405 , https://www.aes.org/e-lib/browse.cfm?elib=16707
- Description: Audio/Video Bridging (AVB) on Ethernet refers to a suite of standards that allows for deterministic and guaranteed delivery of audio and video content on Virtual Local Area Networks (VLAN). A requirement for the networking of audio devices is to allow for remote establishment and destruction of audio stream connections. There are a number of sound control protocols that utilize AVB transport, and this paper describes an approach for common control and interoperability among them. To demonstrate this approach, this paper describes the design and implementation of a command translator that enables communication between AES64 and OSC-networked AVB devices. Results from a quantitative analysis reveal that when a proxy is used for connection management, noticeable delays are not added to a user’s visual and auditory perception.
- Full Text:
- Authors: Foss, Richard , Igumbor, Osedum P
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426978 , vital:72405 , https://www.aes.org/e-lib/browse.cfm?elib=16707
- Description: Audio/Video Bridging (AVB) on Ethernet refers to a suite of standards that allows for deterministic and guaranteed delivery of audio and video content on Virtual Local Area Networks (VLAN). A requirement for the networking of audio devices is to allow for remote establishment and destruction of audio stream connections. There are a number of sound control protocols that utilize AVB transport, and this paper describes an approach for common control and interoperability among them. To demonstrate this approach, this paper describes the design and implementation of a command translator that enables communication between AES64 and OSC-networked AVB devices. Results from a quantitative analysis reveal that when a proxy is used for connection management, noticeable delays are not added to a user’s visual and auditory perception.
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Controls on the formation of Wakkerstroom Vlei, Mpumalanga province, South Africa:
- Joubert, R, Ellery, William F N
- Authors: Joubert, R , Ellery, William F N
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144421 , vital:38344 , DOI: 10.2989/16085914.2012.762897
- Description: The present study investigated controls on the formation of Wakkerstroom Vlei, an 1 000 ha unchannelled valley-bottom wetland on the South African Highveld. Along the uppermost and lowermost reaches of the wetland, where dolerite outcrops occur along the main valley, hydrogeomorphic features typical of geological control on wetland formation are present, including a meandering river channel, oxbow lakes and greater than 3 m deep organic-poor alluvial fill. Along the main body of the wetland, however, floodplain features are absent, alluvial fill is up to 4.5 m deep and contains up to 2 m deep accumulations of peat. These characteristics deviate from the traditional model of dolerite control on wetland formation described by several other studies on Highveld wetland systems.
- Full Text:
- Authors: Joubert, R , Ellery, William F N
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/144421 , vital:38344 , DOI: 10.2989/16085914.2012.762897
- Description: The present study investigated controls on the formation of Wakkerstroom Vlei, an 1 000 ha unchannelled valley-bottom wetland on the South African Highveld. Along the uppermost and lowermost reaches of the wetland, where dolerite outcrops occur along the main valley, hydrogeomorphic features typical of geological control on wetland formation are present, including a meandering river channel, oxbow lakes and greater than 3 m deep organic-poor alluvial fill. Along the main body of the wetland, however, floodplain features are absent, alluvial fill is up to 4.5 m deep and contains up to 2 m deep accumulations of peat. These characteristics deviate from the traditional model of dolerite control on wetland formation described by several other studies on Highveld wetland systems.
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Coping with HIV and AIDS in marginal communities: a case study of Chivanhu Settlement in Nemanwa, Masvingo, Zimbabwe
- Authors: Makonese, Loveness
- Date: 2013
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3337 , http://hdl.handle.net/10962/d1003744
- Description: This thesis seeks to understand and analyse HIV and AIDS and rural livelihoods in Zimbabwe with particular reference to an isolated and marginalised informal settlement called Chivanhu in Masvingo Province. The focus is specifically on questions around HIV susceptibility, AIDS vulnerability and household resilience. In this regard, it is important to recognise that HIV and AIDS cannot be lumped together as one medical or social condition. Rather, there is a progression from HIV infection to AIDS-related chronic illnesses to possible death, and livelihood strategies often alter along this HIV and AIDS time-line. Zimbabwe for over a decade now has gone through a series of economic and political crises which have impacted detrimentally on both urban and rural livelihoods, even for those households which are not directly affected by the HIV and AIDS pandemic. With the economy in free-fall, households have had to pursue a range of livelihood strategies in order to sustain themselves. These socio-economic conditions have in many ways facilitated susceptibility to HIV infection and vulnerability to AIDS. Many studies have examined this in relation to wellentrenched and stable communities in rural Zimbabwe. But the livelihood dynamics for such communities are significantly different to more unstable and informal settlements like Chivanhu, as thesis seeks to show. At the same time, the thesis offers a longitudinal study which is able to map the changes to the livelihoods of infected and affected households in Chivanhu. Though recognising the debilitating effects of the pandemic on these households, it also raises questions about the possible resilience of certain households despite great adversity. In doing so, it goes beyond the individual and household levels of analysis to consider the role of clusters (or groups of households) in responding to the impacts of HIV and AIDS. In this regard, particular emphasis is placed on gender and orphanhood. In the end, the thesis offers a nuanced analysis of the everyday complexities and challenges for affected households in a marginalised and informal rural community in Zimbabwe and thereby makes a contribution to re-theorising HIV and AIDS and rural livelihoods more broadly.
- Full Text:
- Authors: Makonese, Loveness
- Date: 2013
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3337 , http://hdl.handle.net/10962/d1003744
- Description: This thesis seeks to understand and analyse HIV and AIDS and rural livelihoods in Zimbabwe with particular reference to an isolated and marginalised informal settlement called Chivanhu in Masvingo Province. The focus is specifically on questions around HIV susceptibility, AIDS vulnerability and household resilience. In this regard, it is important to recognise that HIV and AIDS cannot be lumped together as one medical or social condition. Rather, there is a progression from HIV infection to AIDS-related chronic illnesses to possible death, and livelihood strategies often alter along this HIV and AIDS time-line. Zimbabwe for over a decade now has gone through a series of economic and political crises which have impacted detrimentally on both urban and rural livelihoods, even for those households which are not directly affected by the HIV and AIDS pandemic. With the economy in free-fall, households have had to pursue a range of livelihood strategies in order to sustain themselves. These socio-economic conditions have in many ways facilitated susceptibility to HIV infection and vulnerability to AIDS. Many studies have examined this in relation to wellentrenched and stable communities in rural Zimbabwe. But the livelihood dynamics for such communities are significantly different to more unstable and informal settlements like Chivanhu, as thesis seeks to show. At the same time, the thesis offers a longitudinal study which is able to map the changes to the livelihoods of infected and affected households in Chivanhu. Though recognising the debilitating effects of the pandemic on these households, it also raises questions about the possible resilience of certain households despite great adversity. In doing so, it goes beyond the individual and household levels of analysis to consider the role of clusters (or groups of households) in responding to the impacts of HIV and AIDS. In this regard, particular emphasis is placed on gender and orphanhood. In the end, the thesis offers a nuanced analysis of the everyday complexities and challenges for affected households in a marginalised and informal rural community in Zimbabwe and thereby makes a contribution to re-theorising HIV and AIDS and rural livelihoods more broadly.
- Full Text:
Corporate social responsibility of private game reserves in the Eastern Cape Province
- Authors: Motala, Amina Sadiq
- Date: 2013
- Subjects: Social responsibility of busines -- South Africa -- Eastern Cape Game reserves -- South Africa -- Eastern Cape Ecotourism -- South Africa -- Eastern Cape Environmental responsibility -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1187 , http://hdl.handle.net/10962/d1004335
- Description: The primary aim of this research study was to determine the current state of practice of corporate social responsibility (CSR) within the ecotourism based private game reserve (PGR) industry in the Eastern Cape Province of South Africa. According to Carroll (1991) four kind of responsibilities constitute total CSR, namely economic, legal, ethical and philanthropic responsibilities. Given the context of this research a fifth responsibility concerning environmental responsibilities was added to Carroll 's (1991) pyramid ofCSR. A descriptive and illustrative case study approach, within the phenomenological research paradigm, was used for the purpose of this research. The unit of analysis is the Indalo group, the Association of Eastern Cape Private Game Reserves, made up of 12 ecotourism based PORs. As the current research focused on eight of the twelve PGRs a mUltiple case study was employed. To give effect to the aim a number of research objectives were identified. Firstly to desclibe and assess the current practice in implementing CSR within the ecotourism based PGR industry in the Eastern Cape Province. Secondly, to assess and evaluate the involvement of ecotourism based PGRs in the Eastern Cape Province in each of the five responsibilities comprising CSR. Thirdly, to identify the challenges faced by ecotourism based PGRs in the Eastern Cape Province with regard to the implementation of CSR initiatives. Lastly to provide pertinent conclusions and recommendations with regard to CSR strategies within the ecotourism based PGR industry in the Eastern Cape Province. Data were collected by means of in-depth interviews with the managers of each reserve. In addition the researcher conducted focus interviews with administrative employees at each of the member reserves of the Indalo group. Additionally the managers of each reserve were requested to respond to a structured five point Likert scale questionnaire based on the research by Aupperle, Carroll and Hatfield (1985). This research study found that the current practice at the Indalo group is towards a strategic, long term approach to CSR that aids in the development of a 'sustainable organisation.' The aspect of ' empowerment' emerged as the essence of the current practice ofCSR of the Indalo group. Based on the current practice it was concluded that the Indalo group is actively involved in the specific components of CSR namely, environmental, economic, legal, ethical and philanthropic responsibilities. With regard to the environmental responsibilities it was concluded that the environment is the foundation upon which all other components of CSR rest. In addition it was concluded that the economic responsibilities, if managed well, are key to unlocking the CSR potential of a reserve as well as ensuring widespread economic development. In terms of the legal and ethical responsibilities it was concluded that tourism policies both at the national and international level have not aided in the development of a CSR agenda of the Indalo group. Furthermore managers of the reserves have been instrumental in cultivating their own legal culture of CSR based on their experience in the tourism industry and their ethical stances. In terms of the philanthropic responsibilities it can be concluded that charitable activities that are long term and strategic in nature allow for direct and indirect benefits to all parties involved. Overall, it can further be concluded that despite Hudson and Miller's (2005:5) view that the "tourism industry is well hehind other industries in terms of CSR" the Indalo group is moving forward in terms of rooting CSR into their everyday operations.
- Full Text:
- Authors: Motala, Amina Sadiq
- Date: 2013
- Subjects: Social responsibility of busines -- South Africa -- Eastern Cape Game reserves -- South Africa -- Eastern Cape Ecotourism -- South Africa -- Eastern Cape Environmental responsibility -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1187 , http://hdl.handle.net/10962/d1004335
- Description: The primary aim of this research study was to determine the current state of practice of corporate social responsibility (CSR) within the ecotourism based private game reserve (PGR) industry in the Eastern Cape Province of South Africa. According to Carroll (1991) four kind of responsibilities constitute total CSR, namely economic, legal, ethical and philanthropic responsibilities. Given the context of this research a fifth responsibility concerning environmental responsibilities was added to Carroll 's (1991) pyramid ofCSR. A descriptive and illustrative case study approach, within the phenomenological research paradigm, was used for the purpose of this research. The unit of analysis is the Indalo group, the Association of Eastern Cape Private Game Reserves, made up of 12 ecotourism based PORs. As the current research focused on eight of the twelve PGRs a mUltiple case study was employed. To give effect to the aim a number of research objectives were identified. Firstly to desclibe and assess the current practice in implementing CSR within the ecotourism based PGR industry in the Eastern Cape Province. Secondly, to assess and evaluate the involvement of ecotourism based PGRs in the Eastern Cape Province in each of the five responsibilities comprising CSR. Thirdly, to identify the challenges faced by ecotourism based PGRs in the Eastern Cape Province with regard to the implementation of CSR initiatives. Lastly to provide pertinent conclusions and recommendations with regard to CSR strategies within the ecotourism based PGR industry in the Eastern Cape Province. Data were collected by means of in-depth interviews with the managers of each reserve. In addition the researcher conducted focus interviews with administrative employees at each of the member reserves of the Indalo group. Additionally the managers of each reserve were requested to respond to a structured five point Likert scale questionnaire based on the research by Aupperle, Carroll and Hatfield (1985). This research study found that the current practice at the Indalo group is towards a strategic, long term approach to CSR that aids in the development of a 'sustainable organisation.' The aspect of ' empowerment' emerged as the essence of the current practice ofCSR of the Indalo group. Based on the current practice it was concluded that the Indalo group is actively involved in the specific components of CSR namely, environmental, economic, legal, ethical and philanthropic responsibilities. With regard to the environmental responsibilities it was concluded that the environment is the foundation upon which all other components of CSR rest. In addition it was concluded that the economic responsibilities, if managed well, are key to unlocking the CSR potential of a reserve as well as ensuring widespread economic development. In terms of the legal and ethical responsibilities it was concluded that tourism policies both at the national and international level have not aided in the development of a CSR agenda of the Indalo group. Furthermore managers of the reserves have been instrumental in cultivating their own legal culture of CSR based on their experience in the tourism industry and their ethical stances. In terms of the philanthropic responsibilities it can be concluded that charitable activities that are long term and strategic in nature allow for direct and indirect benefits to all parties involved. Overall, it can further be concluded that despite Hudson and Miller's (2005:5) view that the "tourism industry is well hehind other industries in terms of CSR" the Indalo group is moving forward in terms of rooting CSR into their everyday operations.
- Full Text:
Could a regulated market approach for rhinoceros horns work in South Africa? Some practical issues and concerns
- Collins, Alan, Fraser, Gavin C G, Snowball, Jeanette D
- Authors: Collins, Alan , Fraser, Gavin C G , Snowball, Jeanette D
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68600 , vital:29292 , http://www.essa2013.org.za/fullpaper/essa2013_2708.pdf
- Description: Publisher version , One of the proposals for fighting rhinoceros poaching is to legalise the trade in rhino horn and adopt a regulated market approach (RMA), which would require a vote at the 2016 CITES meeting in order to overturn the ban on the trade in rhino horn. The legal trade in rhino horn would enable the auctioning of stockpiles of horn and encourage captive breeding programmes. The aim of increasing the supply of horn is to reduce incentives to poach by driving down the price. This paper uses a conceptual/theoretical approach to consider the practical implications of the adoption of an RMA, drawing on demand, supply and production theory. The intention is explicitly to set out some practical concerns and issues that seem to have been underplayed or neglected in most published economic discourse on the subject. To secure a stockpile for some species needs biological success in captive breeding programs (CBPs) but this varies across species and habitats. Rhinoceros herds in a CBP would need relatively spatially extensive terrain and costly permanent security measures, and only appear feasible for the less aggressive “white” rhino. Thus, market price would actually need to be sustained at a high level to cover the start-up and security costs of such a programme that are unlikely to fall significantly. This is a double-edged sword in that the persistent high price of rhino horn provides an incentive for continued poaching activities. Supplementary policy measures that differentiate among consumer groups may also prove necessary.
- Full Text:
- Authors: Collins, Alan , Fraser, Gavin C G , Snowball, Jeanette D
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68600 , vital:29292 , http://www.essa2013.org.za/fullpaper/essa2013_2708.pdf
- Description: Publisher version , One of the proposals for fighting rhinoceros poaching is to legalise the trade in rhino horn and adopt a regulated market approach (RMA), which would require a vote at the 2016 CITES meeting in order to overturn the ban on the trade in rhino horn. The legal trade in rhino horn would enable the auctioning of stockpiles of horn and encourage captive breeding programmes. The aim of increasing the supply of horn is to reduce incentives to poach by driving down the price. This paper uses a conceptual/theoretical approach to consider the practical implications of the adoption of an RMA, drawing on demand, supply and production theory. The intention is explicitly to set out some practical concerns and issues that seem to have been underplayed or neglected in most published economic discourse on the subject. To secure a stockpile for some species needs biological success in captive breeding programs (CBPs) but this varies across species and habitats. Rhinoceros herds in a CBP would need relatively spatially extensive terrain and costly permanent security measures, and only appear feasible for the less aggressive “white” rhino. Thus, market price would actually need to be sustained at a high level to cover the start-up and security costs of such a programme that are unlikely to fall significantly. This is a double-edged sword in that the persistent high price of rhino horn provides an incentive for continued poaching activities. Supplementary policy measures that differentiate among consumer groups may also prove necessary.
- Full Text:
Counting planes
- Authors: Rawlins, Isabel Bethan
- Date: 2013
- Subjects: Prose poems , Flash fiction , Short stories , English , Creative writing (Higher education) , Short stories, South African (English) -- 21st century , South African fiction (English) -- 21st century , South African poetry (English) -- 21st century , English language -- Writing
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:5966 , http://hdl.handle.net/10962/d1001816
- Description: This collection of prose-poems and flash fiction, together with a few short stories, shows how romantic relationships colour our perspectives on the world. The collection has echoes throughout of speakers' voices, theme, imagery and tone. There is a narrative logic too, but working on a subtle level of echo and resonance
- Full Text:
- Authors: Rawlins, Isabel Bethan
- Date: 2013
- Subjects: Prose poems , Flash fiction , Short stories , English , Creative writing (Higher education) , Short stories, South African (English) -- 21st century , South African fiction (English) -- 21st century , South African poetry (English) -- 21st century , English language -- Writing
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:5966 , http://hdl.handle.net/10962/d1001816
- Description: This collection of prose-poems and flash fiction, together with a few short stories, shows how romantic relationships colour our perspectives on the world. The collection has echoes throughout of speakers' voices, theme, imagery and tone. There is a narrative logic too, but working on a subtle level of echo and resonance
- Full Text:
Creating a new declaration of rights : a critical reconstruction of earth jurisprudence's global legislative framework
- Authors: Lenferna, Georges Alexandre
- Date: 2013
- Subjects: Universal Declaration , Rights , Earth , Environment , Ethics , Environmental law, International -- Research , Environmental law, International -- Philosophy , Environmental ethics -- Research , Nature conservation -- Law and legislation -- Research , Jurisprudence -- Research , Law -- Philosophy
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2704 , http://hdl.handle.net/10962/d1001979
- Description: This thesis aims to critique the Universal Declaration of the Rights of Mother Earth and its underlying moral justification in order to provide a stronger and improved version of both. In Chapter 1 I explore what sort of moral justification is necessary to establish the Universal Declaration on firm grounds and explore its relation to environmental ethics and rights discourse. I argue that a non-anthropocentric perspective is necessary to justify the Universal Declaration’s rights. In Chapter 2 I explore the underlying justification of the Universal Declaration as discovered in the works of Cormac Cullinan and Father Thomas Berry. I argue that their ethical framework is indeterminate, has many ambiguities and uncertainties, and, among other problems, it does not provide a clear action-guiding framework. In Chapter 3 I develop an alternative justification for the Universal Declaration. I argue against many predominant moral theories, that in light of our best scientific and moral understanding we should expand the realm of moral concern to include all living beings, a moral theory I call Life’s Imperative. In Chapter 4 I illustrate that Life’s Imperative is a much stronger, more coherent justification for the Universal Declaration, one that coheres with both our best understanding of the natural world and our relation to it, and to an environmental ethic reflective of that relationship. Unfortunately many of the weaknesses in the current implicit justification of the Universal Declaration have also led to it enshrining rights that are themselves problematic. In order to address these issues, I revise its rights to accord with the stronger justification that I established in Chapter 3. The end result of doing so is a revised version of the Universal Declaration
- Full Text:
- Authors: Lenferna, Georges Alexandre
- Date: 2013
- Subjects: Universal Declaration , Rights , Earth , Environment , Ethics , Environmental law, International -- Research , Environmental law, International -- Philosophy , Environmental ethics -- Research , Nature conservation -- Law and legislation -- Research , Jurisprudence -- Research , Law -- Philosophy
- Language: English
- Type: text , Thesis , Masters , MA
- Identifier: vital:2704 , http://hdl.handle.net/10962/d1001979
- Description: This thesis aims to critique the Universal Declaration of the Rights of Mother Earth and its underlying moral justification in order to provide a stronger and improved version of both. In Chapter 1 I explore what sort of moral justification is necessary to establish the Universal Declaration on firm grounds and explore its relation to environmental ethics and rights discourse. I argue that a non-anthropocentric perspective is necessary to justify the Universal Declaration’s rights. In Chapter 2 I explore the underlying justification of the Universal Declaration as discovered in the works of Cormac Cullinan and Father Thomas Berry. I argue that their ethical framework is indeterminate, has many ambiguities and uncertainties, and, among other problems, it does not provide a clear action-guiding framework. In Chapter 3 I develop an alternative justification for the Universal Declaration. I argue against many predominant moral theories, that in light of our best scientific and moral understanding we should expand the realm of moral concern to include all living beings, a moral theory I call Life’s Imperative. In Chapter 4 I illustrate that Life’s Imperative is a much stronger, more coherent justification for the Universal Declaration, one that coheres with both our best understanding of the natural world and our relation to it, and to an environmental ethic reflective of that relationship. Unfortunately many of the weaknesses in the current implicit justification of the Universal Declaration have also led to it enshrining rights that are themselves problematic. In order to address these issues, I revise its rights to accord with the stronger justification that I established in Chapter 3. The end result of doing so is a revised version of the Universal Declaration
- Full Text:
Crime fiction, South Africa : a critical introduction
- Authors: Naidu, Samantha
- Date: 2013
- Language: English
- Type: Article
- Identifier: vital:26315 , http://hdl.handle.net/10962/53743 , http://0-dx.doi.org.wam.seals.ac.za/10.1080/1013929X.2013.833416 , https://orcid.org/0000-0001-9456-8657
- Description: Crime fiction is an emergent category in South African literary studies. This introduction positions South African crime fiction and its scholarship in a global lineage of crime and detective fiction. The survey addresses the question of its literary status as ‘highbrow’ or ‘lowbrow’. It also identifies and describes two distinct sub-genres of South African crime fiction: the crime thriller novel; and the literary detective novel. The argument is that South African crime fiction exhibits a unique capacity for social analysis: a capacity which is being optimised by authors and interrogated by scholars
- Full Text:
- Authors: Naidu, Samantha
- Date: 2013
- Language: English
- Type: Article
- Identifier: vital:26315 , http://hdl.handle.net/10962/53743 , http://0-dx.doi.org.wam.seals.ac.za/10.1080/1013929X.2013.833416 , https://orcid.org/0000-0001-9456-8657
- Description: Crime fiction is an emergent category in South African literary studies. This introduction positions South African crime fiction and its scholarship in a global lineage of crime and detective fiction. The survey addresses the question of its literary status as ‘highbrow’ or ‘lowbrow’. It also identifies and describes two distinct sub-genres of South African crime fiction: the crime thriller novel; and the literary detective novel. The argument is that South African crime fiction exhibits a unique capacity for social analysis: a capacity which is being optimised by authors and interrogated by scholars
- Full Text:
Critical indirect effects of climate change on sub-A ntarctic ecosystem functioning
- Allan, E Louise, Froneman, P William, Durgadoo, Jonathan V, McQuaid, Christopher D, Ansorge, Isabelle J, Richoux, Nicole B
- Authors: Allan, E Louise , Froneman, P William , Durgadoo, Jonathan V , McQuaid, Christopher D , Ansorge, Isabelle J , Richoux, Nicole B
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457934 , vital:75696 , xlink:href="https://doi.org/10.1002/ece3.678"
- Description: Sub‐Antarctic islands represent critical breeding habitats for land‐based top predators that dominate Southern Ocean food webs. Reproduction and molting incur high energetic demands that are sustained at the sub‐Antarctic Prince Edward Islands (PEIs) by both inshore (phytoplankton blooms; “island mass effect”; autochthonous) and offshore (allochthonous) productivity. As the relative contributions of these sustenance pathways are, in turn, affected by oceanographic conditions around the PEIs, we address the consequences of climatically driven changes in the physical environment on this island ecosystem. We show that there has been a measurable long‐term shift in the carbon isotope signatures of the benthos inhabiting the shallow shelf region of the PEIs, most likely reflecting a long‐term decline in enhanced phytoplankton productivity at the islands in response to a climate‐driven shift in the position of the sub‐Antarctic Front. Our results indicate that regional climate change has affected the balance between allochthonous and autochthonous productivity at the PEIs. Over the last three decades, inshore‐feeding top predators at the islands have shown a marked decrease in their population sizes. Conversely, population sizes of offshore‐feeding predators that forage over great distances from the islands have remained stable or increased, with one exception. Population decline of predators that rely heavily on organisms inhabiting the inshore region strongly suggest changes in prey availability, which are likely driven by factors such as fisheries impacts on some prey populations and shifts in competitive interactions among predators. In addition to these local factors, our analysis indicates that changes in prey availability may also result indirectly through regional climate change effects on the islands' marine ecosystem. Most importantly, our results indicate that a fundamental shift in the balance between allochthonous and autochthonous trophic pathways within this island ecosystem may be detected throughout the food web, demonstrating that the most powerful effects of climate change on marine systems may be indirect.
- Full Text:
- Authors: Allan, E Louise , Froneman, P William , Durgadoo, Jonathan V , McQuaid, Christopher D , Ansorge, Isabelle J , Richoux, Nicole B
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/457934 , vital:75696 , xlink:href="https://doi.org/10.1002/ece3.678"
- Description: Sub‐Antarctic islands represent critical breeding habitats for land‐based top predators that dominate Southern Ocean food webs. Reproduction and molting incur high energetic demands that are sustained at the sub‐Antarctic Prince Edward Islands (PEIs) by both inshore (phytoplankton blooms; “island mass effect”; autochthonous) and offshore (allochthonous) productivity. As the relative contributions of these sustenance pathways are, in turn, affected by oceanographic conditions around the PEIs, we address the consequences of climatically driven changes in the physical environment on this island ecosystem. We show that there has been a measurable long‐term shift in the carbon isotope signatures of the benthos inhabiting the shallow shelf region of the PEIs, most likely reflecting a long‐term decline in enhanced phytoplankton productivity at the islands in response to a climate‐driven shift in the position of the sub‐Antarctic Front. Our results indicate that regional climate change has affected the balance between allochthonous and autochthonous productivity at the PEIs. Over the last three decades, inshore‐feeding top predators at the islands have shown a marked decrease in their population sizes. Conversely, population sizes of offshore‐feeding predators that forage over great distances from the islands have remained stable or increased, with one exception. Population decline of predators that rely heavily on organisms inhabiting the inshore region strongly suggest changes in prey availability, which are likely driven by factors such as fisheries impacts on some prey populations and shifts in competitive interactions among predators. In addition to these local factors, our analysis indicates that changes in prey availability may also result indirectly through regional climate change effects on the islands' marine ecosystem. Most importantly, our results indicate that a fundamental shift in the balance between allochthonous and autochthonous trophic pathways within this island ecosystem may be detected throughout the food web, demonstrating that the most powerful effects of climate change on marine systems may be indirect.
- Full Text:
Critical studies in carbon electrode materials with applications in the electroanalysis of the mycotoxin citrinin
- Authors: Niland, Michael John
- Date: 2013
- Subjects: Electrodes, Carbon , Mycotoxins
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4555 , http://hdl.handle.net/10962/d1018256
- Description: Guided by increasing legislation, the analysis of food borne toxins, including mycotoxins, seeks to address market related demands for the development of analytical systems to monitor this threat to food security and human health. This Thesis is directed at the assessment of the application of electrochemistry for direct electroanalysis and characterisation of the mycotoxin citrinin (CIT) in aqueous media as well as fundamental investigations of the surface of polished and oxidised glassy carbon electrodes (GCE). This study provides the first known account of CIT detection through electrochemical methods. Although electrochemically active, CIT current responses (Ip) were highly irreproducible at polished GCE with a coefficient of variation (C.V.) of 20.16 %. As stability of Ip across multiple electrode preparations is a key requirement in electroanalysis, investigations were directed at attaining stability in CIT Ip. Achieving stability in CIT Ip was investigated via two approaches, including: accounting for Ip variability between electrode preparations as a result of variable GCE surface conditions as a post-data-acquisition analysis and secondly, removing Ip variability through modification of GCE. Accounting for variability in Ip was investigated through the application of double layer capacitance as an indicator of the activity of an electrode, and in so doing serving as a relative mediator of Ip responses between electrodes. Application of this procedure dropped CIT C.V. to a third of starting value across polished GCE (C.V. = 7.18 %), chemically oxidised GCE (Pi-GCE, C.V = 8.47 %) and functionalised multi-walled carbon nanotube modified GCE (fMWCNT, C.V. = 25.79 %) and was effective with analysis of structurally distinct molecules, 2,4-dimethylaniline (2,4-DMA) and 1,2,4-trihydroxybenzene (Triol). Furthermore, it afforded the ability to determine discreet solution overlapping data sets of Ip. Stabilising Ip through GCE surface modification was achieved by anodic electro-oxidation of GCE and allowed for direct electroanalysis of CIT and subsequent characterisation and analysis of CIT in complex media as it reduced C.V. of CIT Ip to 0.73 %. Fundamental investigations of the electrode surface condition are described such that the source of variability could be identified and the interactions of CIT with the electrode understood. Two surface oxidation techniques were applied in modification of GCE; anodic electro-oxidation (EOx GCE) and chemical oxidation using piranha solution (Pi-GCE), analysis of which has previously not been reported. Fundamental analyses to determine surface morphology and chemistry of Pi-GCE, EOx-GCE and polished GCE were conducted using high resolution scanning electron microscopy (HRSEM), scanning electrochemical microscopy (SECM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR) and via electroanalytical methods. These studies showed that both oxidation procedures introduced a variety of oxide species at GCE surface, and further that the extent of those species was similar with total % O being 27.67 % and 33.47 % at Pi-GCE and EOx-GCE respectively. Although chemically similar, each surface was morphologically distinct. Electrochemical analyses at the surfaces revealed Pi-GCE to behave more similarly to polished GCE than EOx-GCE. As CIT responses were found to be stable at EOx-GCE (C.V. = 0.73 %) as opposed to Pi-GCE (C.V. = 22.87 %), stability of CIT Ip was likely to be as a result of a physical interaction with electrode morphology rather than interaction on a chemical basis. Morphological analyses revealed polished GCE and Pi-GCE to be highly morphologically irregular at the micro-scale. Although comparatively smooth, the surface morphology of EOx-GCE does not account for the stability of Ip. This study thus proposed a theory to describe the mechanism by which the limited conductivity and porosity of EOx-GCE allow for it to provide a relatively stable surface area within the oxide layer, adjacent to the electrode surface, and thus provided a stable platform for electroanalysis. Voltammetric characterization of CIT at EOx-GCE revealed that anodic oxidation in aqueous media involved an uneven number of electrons to protons via an ECE mechanism. This was illustrated to be nt = 2e- accompanied by the transfer of 1H⁺ per molecule oxidised. A proposed reaction scheme for the initial stages of CIT oxidation was suggested to involve both hydroxyl and carboxyl moieties of the CIT molecule. CIT oxidation was shown to arise as a result of a relatively complex mass transport regime which included both adsorptive and diffusive derived Ip₁. The LOD in buffered aqueous media was found to be 16 nM, a highly competitive result in relation to chromatographic techniques. Further application of EOx-GCE in complex media illustrated that CIT associates non-specifically with the components of food samples, primarily proteins. As a result of this, extraction of CIT from such media is mandatory. Liquid-liquid extraction illustrated a recovery in CIT Ip₁ and in so doing provided a means of accurately and sensitively detecting CIT from food samples with an LOD of 20 nM. These responses were corroborated by HPLC analyses on the same extractions and illustrate the applicability of electroanalysis as an analytical technique.
- Full Text:
- Authors: Niland, Michael John
- Date: 2013
- Subjects: Electrodes, Carbon , Mycotoxins
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4555 , http://hdl.handle.net/10962/d1018256
- Description: Guided by increasing legislation, the analysis of food borne toxins, including mycotoxins, seeks to address market related demands for the development of analytical systems to monitor this threat to food security and human health. This Thesis is directed at the assessment of the application of electrochemistry for direct electroanalysis and characterisation of the mycotoxin citrinin (CIT) in aqueous media as well as fundamental investigations of the surface of polished and oxidised glassy carbon electrodes (GCE). This study provides the first known account of CIT detection through electrochemical methods. Although electrochemically active, CIT current responses (Ip) were highly irreproducible at polished GCE with a coefficient of variation (C.V.) of 20.16 %. As stability of Ip across multiple electrode preparations is a key requirement in electroanalysis, investigations were directed at attaining stability in CIT Ip. Achieving stability in CIT Ip was investigated via two approaches, including: accounting for Ip variability between electrode preparations as a result of variable GCE surface conditions as a post-data-acquisition analysis and secondly, removing Ip variability through modification of GCE. Accounting for variability in Ip was investigated through the application of double layer capacitance as an indicator of the activity of an electrode, and in so doing serving as a relative mediator of Ip responses between electrodes. Application of this procedure dropped CIT C.V. to a third of starting value across polished GCE (C.V. = 7.18 %), chemically oxidised GCE (Pi-GCE, C.V = 8.47 %) and functionalised multi-walled carbon nanotube modified GCE (fMWCNT, C.V. = 25.79 %) and was effective with analysis of structurally distinct molecules, 2,4-dimethylaniline (2,4-DMA) and 1,2,4-trihydroxybenzene (Triol). Furthermore, it afforded the ability to determine discreet solution overlapping data sets of Ip. Stabilising Ip through GCE surface modification was achieved by anodic electro-oxidation of GCE and allowed for direct electroanalysis of CIT and subsequent characterisation and analysis of CIT in complex media as it reduced C.V. of CIT Ip to 0.73 %. Fundamental investigations of the electrode surface condition are described such that the source of variability could be identified and the interactions of CIT with the electrode understood. Two surface oxidation techniques were applied in modification of GCE; anodic electro-oxidation (EOx GCE) and chemical oxidation using piranha solution (Pi-GCE), analysis of which has previously not been reported. Fundamental analyses to determine surface morphology and chemistry of Pi-GCE, EOx-GCE and polished GCE were conducted using high resolution scanning electron microscopy (HRSEM), scanning electrochemical microscopy (SECM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR) and via electroanalytical methods. These studies showed that both oxidation procedures introduced a variety of oxide species at GCE surface, and further that the extent of those species was similar with total % O being 27.67 % and 33.47 % at Pi-GCE and EOx-GCE respectively. Although chemically similar, each surface was morphologically distinct. Electrochemical analyses at the surfaces revealed Pi-GCE to behave more similarly to polished GCE than EOx-GCE. As CIT responses were found to be stable at EOx-GCE (C.V. = 0.73 %) as opposed to Pi-GCE (C.V. = 22.87 %), stability of CIT Ip was likely to be as a result of a physical interaction with electrode morphology rather than interaction on a chemical basis. Morphological analyses revealed polished GCE and Pi-GCE to be highly morphologically irregular at the micro-scale. Although comparatively smooth, the surface morphology of EOx-GCE does not account for the stability of Ip. This study thus proposed a theory to describe the mechanism by which the limited conductivity and porosity of EOx-GCE allow for it to provide a relatively stable surface area within the oxide layer, adjacent to the electrode surface, and thus provided a stable platform for electroanalysis. Voltammetric characterization of CIT at EOx-GCE revealed that anodic oxidation in aqueous media involved an uneven number of electrons to protons via an ECE mechanism. This was illustrated to be nt = 2e- accompanied by the transfer of 1H⁺ per molecule oxidised. A proposed reaction scheme for the initial stages of CIT oxidation was suggested to involve both hydroxyl and carboxyl moieties of the CIT molecule. CIT oxidation was shown to arise as a result of a relatively complex mass transport regime which included both adsorptive and diffusive derived Ip₁. The LOD in buffered aqueous media was found to be 16 nM, a highly competitive result in relation to chromatographic techniques. Further application of EOx-GCE in complex media illustrated that CIT associates non-specifically with the components of food samples, primarily proteins. As a result of this, extraction of CIT from such media is mandatory. Liquid-liquid extraction illustrated a recovery in CIT Ip₁ and in so doing provided a means of accurately and sensitively detecting CIT from food samples with an LOD of 20 nM. These responses were corroborated by HPLC analyses on the same extractions and illustrate the applicability of electroanalysis as an analytical technique.
- Full Text:
Current and potential carbon stocks of trees in urban parking lots in towns of the Eastern Cape, South Africa
- O'Donoghue, Alexandra, Shackleton, Charlie M
- Authors: O'Donoghue, Alexandra , Shackleton, Charlie M
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181037 , vital:43689 , xlink:href="https://doi.org/10.1016/j.ufug.2013.07.001"
- Description: Greening of shopping centre parking lots is a potentially important strategy that can contribute to urban carbon mitigation efforts, improve aesthetics and the shopping experience of consumers, whilst adding to urban biodiversity. Twenty-eight shopping centre parking lots in six Eastern Cape urban centres, South Africa, were sampled to determine tree species composition, density and annual carbon sequestration potential. The best case parking lot found during the study was used as a benchmark to display the difference between current tree density and above-ground carbon stocks relative to the potential optimum. The highest tree density was 66 trees ha−1, whereas the average density across all sampled parking lots was less than half that (27.2 ± 22.6 trees ha−1). The average annual carbon sequestration potential per parking lot was 1390 ± 2503 kg ha−1. Planting density was positively related to annual sequestration rates, whilst parking lot age and the mean annual rainfall of the town had no influence. Mean tree species richness per parking lot was 2.3 ± 1.8 species, with a positive relationship to parking lot size, but not to mean annual rainfall of the site. The majority of trees (62.5%) in parking lots were alien species, although newer parking lots had significantly greater proportions of indigenous species. There was no difference in mean annual carbon sequestration rate per tree between indigenous and alien trees species. Low tree densities and small parking lot areas constrained the potential for earning carbon credits from trees in parking lots. Nonetheless, planners and designers need to be more aware of the potential contribution of trees towards urban sustainability.
- Full Text:
- Authors: O'Donoghue, Alexandra , Shackleton, Charlie M
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181037 , vital:43689 , xlink:href="https://doi.org/10.1016/j.ufug.2013.07.001"
- Description: Greening of shopping centre parking lots is a potentially important strategy that can contribute to urban carbon mitigation efforts, improve aesthetics and the shopping experience of consumers, whilst adding to urban biodiversity. Twenty-eight shopping centre parking lots in six Eastern Cape urban centres, South Africa, were sampled to determine tree species composition, density and annual carbon sequestration potential. The best case parking lot found during the study was used as a benchmark to display the difference between current tree density and above-ground carbon stocks relative to the potential optimum. The highest tree density was 66 trees ha−1, whereas the average density across all sampled parking lots was less than half that (27.2 ± 22.6 trees ha−1). The average annual carbon sequestration potential per parking lot was 1390 ± 2503 kg ha−1. Planting density was positively related to annual sequestration rates, whilst parking lot age and the mean annual rainfall of the town had no influence. Mean tree species richness per parking lot was 2.3 ± 1.8 species, with a positive relationship to parking lot size, but not to mean annual rainfall of the site. The majority of trees (62.5%) in parking lots were alien species, although newer parking lots had significantly greater proportions of indigenous species. There was no difference in mean annual carbon sequestration rate per tree between indigenous and alien trees species. Low tree densities and small parking lot areas constrained the potential for earning carbon credits from trees in parking lots. Nonetheless, planners and designers need to be more aware of the potential contribution of trees towards urban sustainability.
- Full Text:
Curriculum Vitae of Prof Tebello Nyokong (OMB)
- Authors: Nyokong, Tebello
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: vital:7233 , http://hdl.handle.net/10962/d1006180
- Description: Department of Science and Technology (DST) and National Research Foundation (NRF) Professor of Medicinal Chemistry and Nanotechnology and Distinguished Professor of Chemistry at Rhodes University.
- Full Text:
- Authors: Nyokong, Tebello
- Date: 2013
- Language: English
- Type: Article , text
- Identifier: vital:7233 , http://hdl.handle.net/10962/d1006180
- Description: Department of Science and Technology (DST) and National Research Foundation (NRF) Professor of Medicinal Chemistry and Nanotechnology and Distinguished Professor of Chemistry at Rhodes University.
- Full Text:
Customising a BBVC for Asterisk VoIP Services
- Oyedele, Y, Terzoli, Alfredo, Mufeti, K
- Authors: Oyedele, Y , Terzoli, Alfredo , Mufeti, K
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430942 , vital:72730 , https://doi.org/10.1007/978-1-4614-3558-7_62
- Description: Browser-based Voice over Internet Protocol Clients (BBVC) are used to access pre-determined VoIP services from VoIP service providers through Internet connections. For nomadic users within an organisa-tion’s Intranet, connections are made to the Internet to utilise these BBVC. An Intranet with an Asterisk Private Branch Exchange (PBX) as a VoIP provider however can be linked with any form of VoIP client to improve service accessibility for its users. This study aims to find a BBVC that can be customised to provide such accessibility within an Intranet. The study revealed that three BBVC are compatible. One of three BBVC was selected for customisation to provide nomadic acces-sibility to Asterisk. The functionality of the customised BBVC depended on the web technologies used and the available VoIP services.
- Full Text:
- Authors: Oyedele, Y , Terzoli, Alfredo , Mufeti, K
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430942 , vital:72730 , https://doi.org/10.1007/978-1-4614-3558-7_62
- Description: Browser-based Voice over Internet Protocol Clients (BBVC) are used to access pre-determined VoIP services from VoIP service providers through Internet connections. For nomadic users within an organisa-tion’s Intranet, connections are made to the Internet to utilise these BBVC. An Intranet with an Asterisk Private Branch Exchange (PBX) as a VoIP provider however can be linked with any form of VoIP client to improve service accessibility for its users. This study aims to find a BBVC that can be customised to provide such accessibility within an Intranet. The study revealed that three BBVC are compatible. One of three BBVC was selected for customisation to provide nomadic acces-sibility to Asterisk. The functionality of the customised BBVC depended on the web technologies used and the available VoIP services.
- Full Text:
Cytotoxicity of lapachol, β-lapachone and related synthetic 1, 4-naphthoquinones against oesophageal cancer cells:
- Sunassee, Suthananda N, Veale, Clinton G L, Shunmoogam-Gounden, Nelusha, Osoniyi, Omalaja, Hendricks, Denver T, Caira, Mino R, De la Mare, Jo-Anne, Edkins, Adrienne L, Pinto, Antônio V, Da Silva Junior, Eufrânio N, Davies-Coleman, Michael T
- Authors: Sunassee, Suthananda N , Veale, Clinton G L , Shunmoogam-Gounden, Nelusha , Osoniyi, Omalaja , Hendricks, Denver T , Caira, Mino R , De la Mare, Jo-Anne , Edkins, Adrienne L , Pinto, Antônio V , Da Silva Junior, Eufrânio N , Davies-Coleman, Michael T
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165207 , vital:41218 , DOI: 10.1016/j.ejmech.2012.12.048
- Description: Naphthoquinones have been found to have a wide range of biological activities, including cytotoxicity to cancer cells. The secondary metabolites lapachol, α- and β-lapachone and a series of 25 related synthetic 1,4-naphthoquinones were screened against the oesophageal cancer cell line (WHCO1). Most of the compounds exhibited enhanced cytotoxicity (IC50 1.6–11.7 μM) compared to the current drug of choice cisplatin (IC50 = 16.5 μM).
- Full Text:
- Authors: Sunassee, Suthananda N , Veale, Clinton G L , Shunmoogam-Gounden, Nelusha , Osoniyi, Omalaja , Hendricks, Denver T , Caira, Mino R , De la Mare, Jo-Anne , Edkins, Adrienne L , Pinto, Antônio V , Da Silva Junior, Eufrânio N , Davies-Coleman, Michael T
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/165207 , vital:41218 , DOI: 10.1016/j.ejmech.2012.12.048
- Description: Naphthoquinones have been found to have a wide range of biological activities, including cytotoxicity to cancer cells. The secondary metabolites lapachol, α- and β-lapachone and a series of 25 related synthetic 1,4-naphthoquinones were screened against the oesophageal cancer cell line (WHCO1). Most of the compounds exhibited enhanced cytotoxicity (IC50 1.6–11.7 μM) compared to the current drug of choice cisplatin (IC50 = 16.5 μM).
- Full Text:
Dancing with the devil: formative peer assessment and academic performance
- Mostert, Markus, Snowball, Jeanette D
- Authors: Mostert, Markus , Snowball, Jeanette D
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69301 , vital:29483 , https://doi.org/10.1080/07294360.2012.705262
- Description: Peer assessment can be important in developing active and independent learners, as well as providing more and faster feedback in large classes, compared to marking done by tutors. In addition, the evaluative, critical stance required by students in order to assess their peers' work encourages the development of higher-order cognitive skills. Changing roles from being assessed to being an assessor can also improve students' ability to judge and improve on their own work. However, peer assessment does have potential problems and there is some debate as to the appropriate academic level at which to implement it, the kinds of feedback that are given and the ways in which students respond. In addition, there is little evidence that peer assessment has an impact on academic performance. This research reports the results of an online peer assessment exercise for a macroeconomics essay conducted in a large Economics 1 class at Rhodes University. Of the 800 students, about half participated in the peer assessment exercise. Data were collected from students via a formal course evaluation. In addition, a sample of 50 essays was evaluated in terms of the relationship between peer marks and final (tutor) marks received and the impact that peer assessment had on the quality of the final essay submitted. An Ordinary Least Squares regression was used to investigate the impact of peer assessment participation on marks. Results showed that peer marks tended to ‘bunch’ in the 60–68% range, indicating the reluctance of peers to give very high or low marks. In general, peers gave more useful feedback on technical aspects, such as presentation and referencing (which were also the categories in which students most often made improvements), than on content. Regression analysis showed that peer assessment participation was not a significant determinant of final essay mark, but that economics ability and English language proficiency were.
- Full Text: false
- Authors: Mostert, Markus , Snowball, Jeanette D
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69301 , vital:29483 , https://doi.org/10.1080/07294360.2012.705262
- Description: Peer assessment can be important in developing active and independent learners, as well as providing more and faster feedback in large classes, compared to marking done by tutors. In addition, the evaluative, critical stance required by students in order to assess their peers' work encourages the development of higher-order cognitive skills. Changing roles from being assessed to being an assessor can also improve students' ability to judge and improve on their own work. However, peer assessment does have potential problems and there is some debate as to the appropriate academic level at which to implement it, the kinds of feedback that are given and the ways in which students respond. In addition, there is little evidence that peer assessment has an impact on academic performance. This research reports the results of an online peer assessment exercise for a macroeconomics essay conducted in a large Economics 1 class at Rhodes University. Of the 800 students, about half participated in the peer assessment exercise. Data were collected from students via a formal course evaluation. In addition, a sample of 50 essays was evaluated in terms of the relationship between peer marks and final (tutor) marks received and the impact that peer assessment had on the quality of the final essay submitted. An Ordinary Least Squares regression was used to investigate the impact of peer assessment participation on marks. Results showed that peer marks tended to ‘bunch’ in the 60–68% range, indicating the reluctance of peers to give very high or low marks. In general, peers gave more useful feedback on technical aspects, such as presentation and referencing (which were also the categories in which students most often made improvements), than on content. Regression analysis showed that peer assessment participation was not a significant determinant of final essay mark, but that economics ability and English language proficiency were.
- Full Text: false