Assessing the genetic diversity of catface rockcod epinephelus andersoni in the subtropical Western Indian Ocean and modelling the effects of climate change on their distribution
- Authors: Coppinger, Christine Rose
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54499 , vital:26570
- Description: The catface rockcod Epinephelus andersoni is a range-restricted species that is endemic to the southeast coast of Africa from Quissico in Mozambique (subtropical) to Knysna in South Africa (warmtemperate). Its complex life-history, long-lived nature and high residency make E. andersoni potentially vulnerable to over-exploitation. Epinephelus andersoni is an important fishery species and has shown signs of depletion. Due to inadequate information necessary for management and conservation, further research is vital, particularly in the face of potentially significant climatic changes which could put further pressure on E. andersoni. The aim of the study was to provide information for the management of E. andersoni, with considerations for the possibly detrimental effects of future climate change. The objectives of this study were to describe the genetic structure and diversity of E. andersoni and to determine possible range shifts of E. andersoni with future changes in sea surface temperature. Genetic samples were collected throughout the distribution of E. andersoni. Standard DNA extraction and PCR using universal primers were conducted and nuclear (RPS7-1) and mitochondrial (cytochrome b) data were analysed to determine genetic diversity. A combination of nuclear and mitochondrial markers was used to ensure that the results were robust. RPS7-1 haplotype diversity was high (0.801) and an AMOVA on the RPS7-1 data showed significantly high among group variation (ΦCT = 0.204, p < 0.05) between five groups: 1. Quissico to Inhaca; 2. Cape Vidal to Port Edward; 3 Port St Johns to Coffee Bay; 4. Mbashe; 5. Port Alfred. This geographic structuring could be attributed to low gene flow across barriers such as the Port Alfred upwelling cell, the Mozambique Channel eddies and smaller more localised upwelling cells such as the Port St Johns cell. The cytochrome b results contrastingly indicate low haplotype diversity (0.309) and no differentiation (ΦCT = 0.265, p = 0.074) between groups and support the hypothesis of a historical population bottleneck. This may be due to an unusually slower mutation rate of the cytochrome b region than the RPS7-1 region, resulting in the RPS7-1 data showing a more recent picture of diversification. To complement the genetic results, niche modelling techniques were used to determine range shifts of E. andersoni with future temperature trends using species distribution and climatic data. The model illustrated a contraction of the E. andersoni distribution as well as future intensification of various upwelling cells along the south-east African coast including the Port Alfred upwelling cell. Due to the low gene flow across these barriers this intensification could decrease the resilience of E. andersoni, as its range becomes more limited with global change. The genetic data and modelling results combined provide useful information on which to base future fisheries management.
- Full Text:
- Date Issued: 2014
- Authors: Coppinger, Christine Rose
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54499 , vital:26570
- Description: The catface rockcod Epinephelus andersoni is a range-restricted species that is endemic to the southeast coast of Africa from Quissico in Mozambique (subtropical) to Knysna in South Africa (warmtemperate). Its complex life-history, long-lived nature and high residency make E. andersoni potentially vulnerable to over-exploitation. Epinephelus andersoni is an important fishery species and has shown signs of depletion. Due to inadequate information necessary for management and conservation, further research is vital, particularly in the face of potentially significant climatic changes which could put further pressure on E. andersoni. The aim of the study was to provide information for the management of E. andersoni, with considerations for the possibly detrimental effects of future climate change. The objectives of this study were to describe the genetic structure and diversity of E. andersoni and to determine possible range shifts of E. andersoni with future changes in sea surface temperature. Genetic samples were collected throughout the distribution of E. andersoni. Standard DNA extraction and PCR using universal primers were conducted and nuclear (RPS7-1) and mitochondrial (cytochrome b) data were analysed to determine genetic diversity. A combination of nuclear and mitochondrial markers was used to ensure that the results were robust. RPS7-1 haplotype diversity was high (0.801) and an AMOVA on the RPS7-1 data showed significantly high among group variation (ΦCT = 0.204, p < 0.05) between five groups: 1. Quissico to Inhaca; 2. Cape Vidal to Port Edward; 3 Port St Johns to Coffee Bay; 4. Mbashe; 5. Port Alfred. This geographic structuring could be attributed to low gene flow across barriers such as the Port Alfred upwelling cell, the Mozambique Channel eddies and smaller more localised upwelling cells such as the Port St Johns cell. The cytochrome b results contrastingly indicate low haplotype diversity (0.309) and no differentiation (ΦCT = 0.265, p = 0.074) between groups and support the hypothesis of a historical population bottleneck. This may be due to an unusually slower mutation rate of the cytochrome b region than the RPS7-1 region, resulting in the RPS7-1 data showing a more recent picture of diversification. To complement the genetic results, niche modelling techniques were used to determine range shifts of E. andersoni with future temperature trends using species distribution and climatic data. The model illustrated a contraction of the E. andersoni distribution as well as future intensification of various upwelling cells along the south-east African coast including the Port Alfred upwelling cell. Due to the low gene flow across these barriers this intensification could decrease the resilience of E. andersoni, as its range becomes more limited with global change. The genetic data and modelling results combined provide useful information on which to base future fisheries management.
- Full Text:
- Date Issued: 2014
An exploration of James Dreier’s Standard Tune Learning Sequence in a self-directed learning environment : an interpretative phenomenological analysis
- Authors: Ellis, Stephen James
- Date: 2014
- Subjects: Dreier, James Drum -- Performance -- Studies and exercises Drum -- Methods -- Self-instruction Drum -- Instruction and study Drummers (Musicians)
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2680 , http://hdl.handle.net/10962/d1011312
- Description: This qualitative case study was undertaken in order to explore the experiences of drum set students who apply themselves to James Dreier’s Standard Tune Learning Sequence (STLS) in a self-directed learning environment. These experiences ultimately shed light on how best to implement Differentiated Instruction to the STLS. The study draws on the experience of three adult drum students under the instruction of the author. The students were provided with the STLS and left to proceed with it on their own. They were asked to keep a record of their progress in the form of a learning journal. These learning journals were used, in conjunction with transcribed interviews and learner profiles, as data for this study and as such were subjected to Interpretative Phenomenological Analysis. The study recognizes three factors which affect the student’s successful progression through the STLS: readiness, interest and meaning. Each factor is discussed in relation to literature on differentiated Instruction. Recommendations are made regarding the implementation of Differentiated Instruction to the STLS.
- Full Text:
- Date Issued: 2014
- Authors: Ellis, Stephen James
- Date: 2014
- Subjects: Dreier, James Drum -- Performance -- Studies and exercises Drum -- Methods -- Self-instruction Drum -- Instruction and study Drummers (Musicians)
- Language: English
- Type: Thesis , Masters , MMus
- Identifier: vital:2680 , http://hdl.handle.net/10962/d1011312
- Description: This qualitative case study was undertaken in order to explore the experiences of drum set students who apply themselves to James Dreier’s Standard Tune Learning Sequence (STLS) in a self-directed learning environment. These experiences ultimately shed light on how best to implement Differentiated Instruction to the STLS. The study draws on the experience of three adult drum students under the instruction of the author. The students were provided with the STLS and left to proceed with it on their own. They were asked to keep a record of their progress in the form of a learning journal. These learning journals were used, in conjunction with transcribed interviews and learner profiles, as data for this study and as such were subjected to Interpretative Phenomenological Analysis. The study recognizes three factors which affect the student’s successful progression through the STLS: readiness, interest and meaning. Each factor is discussed in relation to literature on differentiated Instruction. Recommendations are made regarding the implementation of Differentiated Instruction to the STLS.
- Full Text:
- Date Issued: 2014
Crumpled hearts
- Authors: Crain, Patricia Ann
- Date: 2014
- Subjects: South African fiction (English) -- 21st century , Creative writing (Higher education) , English language -- Writing , South African fiction (English) -- Study and teaching (Higher)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5984 , http://hdl.handle.net/10962/d1015676
- Description: A middle-aged woman, living in Johannesburg, has an experience which catapults her into changing her life. In the process of confronting her alcoholism, she realizes how patterns of addiction extend to other areas of her life and tries to make sense of the tragic events that have occurred. Her world becomes a different place as she questions everything that she has been taught about relationships, religion, race and her place in society. In the search for answers she uncovers stories about the lives of her parents, grandparents, relatives, friends and acquaintances. Embarking on a journey of discovery and rediscovery through her experiences and those of others, she explores the ways in which the things that she thought she knew defined her behaviour and expression of herself.
- Full Text:
- Date Issued: 2014
- Authors: Crain, Patricia Ann
- Date: 2014
- Subjects: South African fiction (English) -- 21st century , Creative writing (Higher education) , English language -- Writing , South African fiction (English) -- Study and teaching (Higher)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5984 , http://hdl.handle.net/10962/d1015676
- Description: A middle-aged woman, living in Johannesburg, has an experience which catapults her into changing her life. In the process of confronting her alcoholism, she realizes how patterns of addiction extend to other areas of her life and tries to make sense of the tragic events that have occurred. Her world becomes a different place as she questions everything that she has been taught about relationships, religion, race and her place in society. In the search for answers she uncovers stories about the lives of her parents, grandparents, relatives, friends and acquaintances. Embarking on a journey of discovery and rediscovery through her experiences and those of others, she explores the ways in which the things that she thought she knew defined her behaviour and expression of herself.
- Full Text:
- Date Issued: 2014
Undertaking to care and to protect : The experience of killing healthy homeless animals in South Africa
- Authors: Van Zyl, Henriette Louise
- Date: 2014
- Subjects: Animal welfare -- Moral and ethical aspects -- South Africa , Euthanasia of animals -- South Africa , Euthanasia of animals -- Psychological aspects , Human-animal relationships -- South Africa , Animal rights -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3245 , http://hdl.handle.net/10962/d1013577
- Description: Although animal welfare workers overwhelmingly describe themselves as animal lovers the exigencies of day to day animal welfare work often require that they perform euthanasia of healthy animals as part of welfare shelter management, and animal population control. In this research study, the particular burdens placed upon seven South Animal welfare workers who are required to rescue, care for, nurture and rehabilitate the animals in their care; while simultaneously being required to kill these same – often physically and behaviourally healthy - animals after a specific period of time, or in response to various logistical, procedural and practical intricacies, ranging from lack of space and resources to an unavailability of suitable homes; are explored from an interpretative phenomenological approach using the Interpretative Phenomenological Method (IPA), and from a South African perspective. It was found that animal-loving individuals engaged in the care and subsequent euthanasia of healthy animals report experiencing profound personal, interpersonal and professional and ideological (dis)stress related to guilt, sorrow, moral unease and horror. Four themes emerged from interview data, which are discussed in relation to relevant research and literature. Experiences in a South African context were found to be very much aligned with those reported in previous research and literature pertaining to this topic. In particular, it was found that there is a need to articulate specifically, and precisely the nature of the act. It is proposed that the term “Agapéthanasia” would be appropriate and useful in this field.
- Full Text:
- Date Issued: 2014
- Authors: Van Zyl, Henriette Louise
- Date: 2014
- Subjects: Animal welfare -- Moral and ethical aspects -- South Africa , Euthanasia of animals -- South Africa , Euthanasia of animals -- Psychological aspects , Human-animal relationships -- South Africa , Animal rights -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3245 , http://hdl.handle.net/10962/d1013577
- Description: Although animal welfare workers overwhelmingly describe themselves as animal lovers the exigencies of day to day animal welfare work often require that they perform euthanasia of healthy animals as part of welfare shelter management, and animal population control. In this research study, the particular burdens placed upon seven South Animal welfare workers who are required to rescue, care for, nurture and rehabilitate the animals in their care; while simultaneously being required to kill these same – often physically and behaviourally healthy - animals after a specific period of time, or in response to various logistical, procedural and practical intricacies, ranging from lack of space and resources to an unavailability of suitable homes; are explored from an interpretative phenomenological approach using the Interpretative Phenomenological Method (IPA), and from a South African perspective. It was found that animal-loving individuals engaged in the care and subsequent euthanasia of healthy animals report experiencing profound personal, interpersonal and professional and ideological (dis)stress related to guilt, sorrow, moral unease and horror. Four themes emerged from interview data, which are discussed in relation to relevant research and literature. Experiences in a South African context were found to be very much aligned with those reported in previous research and literature pertaining to this topic. In particular, it was found that there is a need to articulate specifically, and precisely the nature of the act. It is proposed that the term “Agapéthanasia” would be appropriate and useful in this field.
- Full Text:
- Date Issued: 2014
The media, Equal Education and school learners : an investigation of the possibility of 'political listening' in the South African education crisis
- Mufamadi, Azwihangwisi Eugene
- Authors: Mufamadi, Azwihangwisi Eugene
- Date: 2014
- Subjects: Equal Education (Nonprofit organisation) Journalism, Educational -- South Africa Educational equalization -- South Africa Journalism -- Political aspects -- South Africa Education -- Citizen participation Educational change -- South Africa Qualitative research
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3524 , http://hdl.handle.net/10962/d1011874
- Description: This study sets out to investigate democratic participation in South Africa and the role that media play and can potentially play within this context. It considers a social movement, as one way in which citizens can organise themselves and make their voices heard to improve their chances of making a meaningful contribution to democracy. It employs Susan Bickford's theory of 'political listening', which offers a potential solution to the lack of political representativeness and inclusiveness, by focusing on the way citizens relate to each other through speaking, listening and dialogue. This study examines whether the interaction between learners and the social movement Equal Education could be considered 'political listening', and the current and possible role of the media within this context of participation. The study also attempts to develop and make a contribution to the language of description for the theory of political listening in order to map it onto the data. Using evidence or data gathered through observation of Equal Education's youth group meetings with learners and in-depth interviews with learners, youth group facilitators, Equal Education staff members and journalists, this study shows how the interaction amongst learners and between Equal Education and learners could be considered political listening and how the social movement works as a democratic project which offers learners an opportunity to exercise their citizenship. Furthermore, it also details the current role of the media and possible role of the media as perceived by Equal Education, learners and by journalists who report on Equal Education's activities. The study does not make conclusive claims about whether 'political listening' occurs between Equal Education and learners and the media because the study is exploratory in nature and involves a lot of trial and error when it comes to applying the theory of political listening to interview and textual data, which is a communication context that the theory is only beginning to chart.
- Full Text:
- Date Issued: 2014
- Authors: Mufamadi, Azwihangwisi Eugene
- Date: 2014
- Subjects: Equal Education (Nonprofit organisation) Journalism, Educational -- South Africa Educational equalization -- South Africa Journalism -- Political aspects -- South Africa Education -- Citizen participation Educational change -- South Africa Qualitative research
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3524 , http://hdl.handle.net/10962/d1011874
- Description: This study sets out to investigate democratic participation in South Africa and the role that media play and can potentially play within this context. It considers a social movement, as one way in which citizens can organise themselves and make their voices heard to improve their chances of making a meaningful contribution to democracy. It employs Susan Bickford's theory of 'political listening', which offers a potential solution to the lack of political representativeness and inclusiveness, by focusing on the way citizens relate to each other through speaking, listening and dialogue. This study examines whether the interaction between learners and the social movement Equal Education could be considered 'political listening', and the current and possible role of the media within this context of participation. The study also attempts to develop and make a contribution to the language of description for the theory of political listening in order to map it onto the data. Using evidence or data gathered through observation of Equal Education's youth group meetings with learners and in-depth interviews with learners, youth group facilitators, Equal Education staff members and journalists, this study shows how the interaction amongst learners and between Equal Education and learners could be considered political listening and how the social movement works as a democratic project which offers learners an opportunity to exercise their citizenship. Furthermore, it also details the current role of the media and possible role of the media as perceived by Equal Education, learners and by journalists who report on Equal Education's activities. The study does not make conclusive claims about whether 'political listening' occurs between Equal Education and learners and the media because the study is exploratory in nature and involves a lot of trial and error when it comes to applying the theory of political listening to interview and textual data, which is a communication context that the theory is only beginning to chart.
- Full Text:
- Date Issued: 2014
Predation by alien largemouth bass, Micropterus salmoides Lacepéde 1802 (Centrarchidae: Perciformes), on indigenous marine fish species in the Kowie System, South Africa
- Authors: Magoro, Mandla Leon
- Date: 2014
- Subjects: Largemouth bass -- South Africa -- Port Alfred , Largemouth bass -- Food -- South Africa -- Port Alfred , Estuarine fishes -- South Africa -- Port Alfred , Estuarine fishes -- Predators of , Centrarchidae , Fishes -- Effect of human beings on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5851 , http://hdl.handle.net/10962/d1011939 , Largemouth bass -- South Africa -- Port Alfred , Largemouth bass -- Food -- South Africa -- Port Alfred , Estuarine fishes -- South Africa -- Port Alfred , Estuarine fishes -- Predators of , Centrarchidae , Fishes -- Effect of human beings on
- Description: Estuaries serve as nursery areas for a large number of estuary-associated fish species. Some of these taxa also use river catchments as nursery areas. During the upstream migration of this latter group, the juveniles are prone to predation by native and alien predatory fish inhabiting the system. The rate of invasion of ecosystems by alien organisms can be directly linked to anthropogenic influences, including both intentional and unintentional introductions by alien organisms into new regions. The largemouth bass, Micropterus salmoides, is a facultative piscivorous fish that has been successfully introduced worldwide for the main purpose of sport fishing. Where introduced, it has been found to negatively impact native fish and invertebrate species through predation, competitive exclusion and displacement of indigenous fish species. The aim of this thesis was to investigate the predatory impact of largemouth bass on the estuary-associated Cape moony Monodactylus falciformis, Cape stumpnose Rhabdosargus holubi and freshwater mullet Myxus capensis in the lower Kowie River of the Eastern Cape Province, South Africa. A combination of approaches was employed during this study. Stomach contents, stable isotopes and fatty acid analyses were employed for the reconstruction of the diet of largemouth bass. Acoustic telemetry was used to elucidate largemouth bass movements, particularly their ability to enter the upper reaches of the Kowie Estuary. Stomach contents and stable isotopes analyses showed that M. salmoides exhibit an ontogenic shift in diet, with small and medium sized individuals consuming the higher proportion of fish prey, while large sized individuals mostly consumed invertebrates such as crabs (Potamonautes sidneyi) and Odonata larvae, while consuming only a small proportion of estuary-associated fish. Fatty acid analysis only showed a direct connection between the fatty acid profiles of largemouth bass and those of M. capensis and M. falciformis. The acoustic telemetry results indicated that some M. salmoides individuals periodically move into the upper reaches of the estuary following river flood events. The results obtained from all these approaches highlight the risk posed by largemouth bass introductions on indigenous fish species, particularly those that enter the areas occupied by these top predators.
- Full Text:
- Date Issued: 2014
- Authors: Magoro, Mandla Leon
- Date: 2014
- Subjects: Largemouth bass -- South Africa -- Port Alfred , Largemouth bass -- Food -- South Africa -- Port Alfred , Estuarine fishes -- South Africa -- Port Alfred , Estuarine fishes -- Predators of , Centrarchidae , Fishes -- Effect of human beings on
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5851 , http://hdl.handle.net/10962/d1011939 , Largemouth bass -- South Africa -- Port Alfred , Largemouth bass -- Food -- South Africa -- Port Alfred , Estuarine fishes -- South Africa -- Port Alfred , Estuarine fishes -- Predators of , Centrarchidae , Fishes -- Effect of human beings on
- Description: Estuaries serve as nursery areas for a large number of estuary-associated fish species. Some of these taxa also use river catchments as nursery areas. During the upstream migration of this latter group, the juveniles are prone to predation by native and alien predatory fish inhabiting the system. The rate of invasion of ecosystems by alien organisms can be directly linked to anthropogenic influences, including both intentional and unintentional introductions by alien organisms into new regions. The largemouth bass, Micropterus salmoides, is a facultative piscivorous fish that has been successfully introduced worldwide for the main purpose of sport fishing. Where introduced, it has been found to negatively impact native fish and invertebrate species through predation, competitive exclusion and displacement of indigenous fish species. The aim of this thesis was to investigate the predatory impact of largemouth bass on the estuary-associated Cape moony Monodactylus falciformis, Cape stumpnose Rhabdosargus holubi and freshwater mullet Myxus capensis in the lower Kowie River of the Eastern Cape Province, South Africa. A combination of approaches was employed during this study. Stomach contents, stable isotopes and fatty acid analyses were employed for the reconstruction of the diet of largemouth bass. Acoustic telemetry was used to elucidate largemouth bass movements, particularly their ability to enter the upper reaches of the Kowie Estuary. Stomach contents and stable isotopes analyses showed that M. salmoides exhibit an ontogenic shift in diet, with small and medium sized individuals consuming the higher proportion of fish prey, while large sized individuals mostly consumed invertebrates such as crabs (Potamonautes sidneyi) and Odonata larvae, while consuming only a small proportion of estuary-associated fish. Fatty acid analysis only showed a direct connection between the fatty acid profiles of largemouth bass and those of M. capensis and M. falciformis. The acoustic telemetry results indicated that some M. salmoides individuals periodically move into the upper reaches of the estuary following river flood events. The results obtained from all these approaches highlight the risk posed by largemouth bass introductions on indigenous fish species, particularly those that enter the areas occupied by these top predators.
- Full Text:
- Date Issued: 2014
Synthesis and characterization of NaYGdF4 upconversion nanoparticles and an investigation of their effects on the spectroscopic properties of two phthalocyanine dyes
- Authors: Taylor, Jessica Mary
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54621 , vital:26594
- Description: Sphere and star shaped NaYGdF4:Yb/Er(Tm) upconversion nanoparticles were successfully synthesized utilizing a methanol assisted thermal decomposition approach and their chemical, spectroscopic and fluorescence properties were fully characterized. In addition, their influence on the spectroscopic and fluorescence properties of two phthalocyanines (Pcs) (unsubstituted tetrathiophenoxy phthalocyanine (H2Pc) and aluminium octacarboxy phthalocyanine (Cl)AlOCPc) was investigated. Upconversion nanoparticles were found to produce characteristic upconversion fluorescence emissions in the blue, green, red and NIR regions and were also shown to possess paramagnetic properties. Simple mixing with an H2Pc in toluene was found to exert no change on the spectroscopic or fluorescence properties of the Pc while covalent conjugation to a (Cl)AlOCPc resulted in a large Q band blue shift accompanied by a decrease in fluorescence lifetimes in DMSO. The red light excitation mediated singlet oxygen generation of the H2Pc mixed with upconversion nanoparticles was investigated and singlet oxygen fluorescence lifetimes were found to decrease in the presence of the nanoparticles. Upconversion mediated singlet oxygen generation, by way of resonance energy transfer to the Pc, was also attempted using 972 nm excitation; however, no singlet oxygen was detected utilizing singlet oxygen NIR emission detection. Pending further work using alternative singlet oxygen detection methods, this suggests that while upconversion nanoparticles possess excellent fluorescent imaging capabilities, they are relatively inefficient in inducing singlet oxygen production simply when mixed with phthalocyanines. Despite this, by combining phthalocyanines and upconversion nanoparticles, we present a system capable of: multimodal imaging, using both upconversion and phthalocyanines emissions, singlet oxygen generation, via direct excitation of the phthalocyanine with red laser light, and, possibly, magnetic resonance imaging, as a result of doping the upconversion nanoparticles with Gd3+ ions.
- Full Text:
- Date Issued: 2014
- Authors: Taylor, Jessica Mary
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/54621 , vital:26594
- Description: Sphere and star shaped NaYGdF4:Yb/Er(Tm) upconversion nanoparticles were successfully synthesized utilizing a methanol assisted thermal decomposition approach and their chemical, spectroscopic and fluorescence properties were fully characterized. In addition, their influence on the spectroscopic and fluorescence properties of two phthalocyanines (Pcs) (unsubstituted tetrathiophenoxy phthalocyanine (H2Pc) and aluminium octacarboxy phthalocyanine (Cl)AlOCPc) was investigated. Upconversion nanoparticles were found to produce characteristic upconversion fluorescence emissions in the blue, green, red and NIR regions and were also shown to possess paramagnetic properties. Simple mixing with an H2Pc in toluene was found to exert no change on the spectroscopic or fluorescence properties of the Pc while covalent conjugation to a (Cl)AlOCPc resulted in a large Q band blue shift accompanied by a decrease in fluorescence lifetimes in DMSO. The red light excitation mediated singlet oxygen generation of the H2Pc mixed with upconversion nanoparticles was investigated and singlet oxygen fluorescence lifetimes were found to decrease in the presence of the nanoparticles. Upconversion mediated singlet oxygen generation, by way of resonance energy transfer to the Pc, was also attempted using 972 nm excitation; however, no singlet oxygen was detected utilizing singlet oxygen NIR emission detection. Pending further work using alternative singlet oxygen detection methods, this suggests that while upconversion nanoparticles possess excellent fluorescent imaging capabilities, they are relatively inefficient in inducing singlet oxygen production simply when mixed with phthalocyanines. Despite this, by combining phthalocyanines and upconversion nanoparticles, we present a system capable of: multimodal imaging, using both upconversion and phthalocyanines emissions, singlet oxygen generation, via direct excitation of the phthalocyanine with red laser light, and, possibly, magnetic resonance imaging, as a result of doping the upconversion nanoparticles with Gd3+ ions.
- Full Text:
- Date Issued: 2014
Development and assessment of sustained release stavudine loaded microparticles
- Authors: Zindove, Chiedza Cathrine
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/54722 , vital:26603
- Description:
Stavudine (D4T) has been used as first line treatment for HIV/AIDS and is part of highly active anti retroviral treatment (HAART). It is an affordable medicine and its use is beneficial in resource limited settings. However D4T exhibits dose dependent side effects that may lead to non-adherence in patients. This study was undertaken to formulate, develop and manufacture a dosage form that could reduce dose dependent side effects by decreasing the dose of D4T but still exhibit antiretroviral (ARV) activity. The use of sustained release (SR) formulations of D4T that ensure constant levels of the D4T in the body would not only optimize therapy but also reduce the incidence of side effects thereby increasing patient adherence. SR microparticles containing 30mg D4T were manufactured and loaded into size 3 hard gelatine capsules prior to analysis. The D4T microparticles were manufactured by microencapsulation using non-aqueous oil-in-oil solvent evaporation approach. D4T-excipient, excipient-excipient interactions and D4T purity were assessed using Infrared Spectroscopy (IR), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Copolymers synthesized from acrylic and methacrylic acid esters viz., Eudragit® RSPO and S100 were used as rate retardant materials and the effect of microcrystalline cellulose (Avicel® PH102) on the microparticles was also investigated. Magnesium stearate was used as a droplet stabilizer and n-hexane was added to harden the microspheres formed in a liquid paraffin continuous phase. The microparticles were optimized using a Box Behnken design and Response Surface Methodology (RSM). The microparticles were characterized in terms of their flow properties and encapsulation efficiency (% EE), in addition to visualization of the surface morphology with Scanning Electron Microscopy. In vitro D4T release studies were performed using USP Apparatus III in media of different pH and the samples were analysed using a validated High Performance Liquid Chromatographic (HPLC) method with ultraviolet (UV) detection that had been developed and optimized using a Central Composite Design (CCD). The method was validated according to ICH guidelines. The IR spectra and DSC thermographs revealed that D4T exhibited thermal stability and there was no evidence of D4T-excipient and excipient-excipient interactions. The microparticles that were produced were white, free flowing and were obtained in a high yield with high encapsulation efficiency. Scanning Electron Microscopy studies revealed that the microparticles were spherical and porous in nature. In vitro D4T release extended to 12 hours and the mechanism of release was established using model dependent methods by fitting the data to a Zero order, First order, Higuchi and Hixson Crowell model. It was observed that the mechanism of D4T release was diffusion-controlled and that the data was best fitted to the Higuchi model with correlation coefficients > 0.9. The release mechanism was confirmed using the Korsmeyer-Peppas model that revealed that most of the formulations exhibited anomalous transport kinetics with the release exponent, n, ranging from 0.5
- Full Text:
- Date Issued: 2014
- Authors: Zindove, Chiedza Cathrine
- Date: 2014
- Language: English
- Type: text , Thesis , Masters , MPharm
- Identifier: http://hdl.handle.net/10962/54722 , vital:26603
- Description:
Stavudine (D4T) has been used as first line treatment for HIV/AIDS and is part of highly active anti retroviral treatment (HAART). It is an affordable medicine and its use is beneficial in resource limited settings. However D4T exhibits dose dependent side effects that may lead to non-adherence in patients. This study was undertaken to formulate, develop and manufacture a dosage form that could reduce dose dependent side effects by decreasing the dose of D4T but still exhibit antiretroviral (ARV) activity. The use of sustained release (SR) formulations of D4T that ensure constant levels of the D4T in the body would not only optimize therapy but also reduce the incidence of side effects thereby increasing patient adherence. SR microparticles containing 30mg D4T were manufactured and loaded into size 3 hard gelatine capsules prior to analysis. The D4T microparticles were manufactured by microencapsulation using non-aqueous oil-in-oil solvent evaporation approach. D4T-excipient, excipient-excipient interactions and D4T purity were assessed using Infrared Spectroscopy (IR), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). Copolymers synthesized from acrylic and methacrylic acid esters viz., Eudragit® RSPO and S100 were used as rate retardant materials and the effect of microcrystalline cellulose (Avicel® PH102) on the microparticles was also investigated. Magnesium stearate was used as a droplet stabilizer and n-hexane was added to harden the microspheres formed in a liquid paraffin continuous phase. The microparticles were optimized using a Box Behnken design and Response Surface Methodology (RSM). The microparticles were characterized in terms of their flow properties and encapsulation efficiency (% EE), in addition to visualization of the surface morphology with Scanning Electron Microscopy. In vitro D4T release studies were performed using USP Apparatus III in media of different pH and the samples were analysed using a validated High Performance Liquid Chromatographic (HPLC) method with ultraviolet (UV) detection that had been developed and optimized using a Central Composite Design (CCD). The method was validated according to ICH guidelines. The IR spectra and DSC thermographs revealed that D4T exhibited thermal stability and there was no evidence of D4T-excipient and excipient-excipient interactions. The microparticles that were produced were white, free flowing and were obtained in a high yield with high encapsulation efficiency. Scanning Electron Microscopy studies revealed that the microparticles were spherical and porous in nature. In vitro D4T release extended to 12 hours and the mechanism of release was established using model dependent methods by fitting the data to a Zero order, First order, Higuchi and Hixson Crowell model. It was observed that the mechanism of D4T release was diffusion-controlled and that the data was best fitted to the Higuchi model with correlation coefficients > 0.9. The release mechanism was confirmed using the Korsmeyer-Peppas model that revealed that most of the formulations exhibited anomalous transport kinetics with the release exponent, n, ranging from 0.5
- Full Text:
- Date Issued: 2014
The genetic stock structure and distribution of Chrysoblephus Puniceus, a commercially important transboundary linefish species, endemic to the South West Indian Ocean
- Authors: Duncan, Murray Ian
- Date: 2014
- Subjects: Sparidae , Fishes -- Indian Ocean , Fish populations , Fishery management , Fish stock assessment -- South Africa , Fish stock assessment -- Mozambique , Overfishing , Habitat conservation , Fishes -- Genetics , Fishes -- Climatic factors , Fishes -- Variation , Fishes -- Migration
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5360 , http://hdl.handle.net/10962/d1011868 , Sparidae , Fishes -- Indian Ocean , Fish populations , Fishery management , Fish stock assessment -- South Africa , Fish stock assessment -- Mozambique , Overfishing , Habitat conservation , Fishes -- Genetics , Fishes -- Climatic factors , Fishes -- Variation , Fishes -- Migration
- Description: Chrysoblephus puniceus is an over-exploited linefish species, endemic to the coastlines off southern Mozambique and eastern South Africa. Over-exploitation and habitat loss are two of the biggest threats to the sustainability of fisheries globally. Assessing the genetic stock structure (a prerequisite for effective management) and predicting climate related range changes will provide a better understanding of these threats to C. puniceus which can be used to improve the sustainability of the fishery. Two hundred and eighty four genetic samples were collected from eight sampling sites between Ponta da Barra in Mozambique and Coffee Bay in South Africa. The mitochondrial control region and ten microsatellite loci were amplified to analyse the stock structure of C. puniceus. The majority of microsatellite and mtDNA pairwise population comparisons were not significant (P > 0.05) although Xai Xai and Inhaca populations had some significant population comparisons for mtDNA (P < 0.05). AMOVA did not explain any significant variation at the between groups hierarchical level for any pre-defined groupings except for a mtDNA grouping which separated out Xai Xai and Inhaca from other sampling sites. SAMOVA, isolation by distance tests, structure analysis, principle component analysis and spatial autocorrelation analysis all indicated a single population of C. puniceus as being most likely. The migrate-n analysis provided evidence of current driven larval transport, with net migration rates influenced by current dynamics.Two hundred and thirty six unique presence points of C. puniceus were correlated with seasonal maximum and minimum temperature data and bathymetry to model the current distribution and predict future distribution changes of the species up until 2030. Eight individual species distribution models were developed and combined into a mean ensemble model using the Biomod2 package. Winter minimum temperature was the most important variable in determining models outputs. Overall the ensemble model was accurate with a true skills statistic score of 0.962. Binary transformed mean ensemble models predicted a northern and southern range contraction of C. puniceus' distribution of 15 percent; by 2030. The mean ensemble probability of occurrence models indicated that C. puniceus' abundance is likely to decrease off the southern Mozambique coastline but remain high off KwaZulu-Natal. The results of the genetic analysis support the theory of external recruitment sustaining the KwaZulu Natal fishery for C. puniceus. While the high genetic diversity and connectivity may make C. puniceus more resilient to disturbances, the loss of 15 percent; distribution and 11 percent; genetic diversity by 2030 will increase the species vulnerability. The decrease in abundance of C. puniceus off southern Mozambique together with current widespread exploitation levels could result in the collapse of the fishery. A single transboundary stock of C. puniceus highlights the need for co-management of the species. A combined stock assessment between South Africa and Mozambique and the development of further Marine Protected Areas off southern Mozambique are suggested as management options to minimise the vulnerability of this species.
- Full Text:
- Date Issued: 2014
- Authors: Duncan, Murray Ian
- Date: 2014
- Subjects: Sparidae , Fishes -- Indian Ocean , Fish populations , Fishery management , Fish stock assessment -- South Africa , Fish stock assessment -- Mozambique , Overfishing , Habitat conservation , Fishes -- Genetics , Fishes -- Climatic factors , Fishes -- Variation , Fishes -- Migration
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5360 , http://hdl.handle.net/10962/d1011868 , Sparidae , Fishes -- Indian Ocean , Fish populations , Fishery management , Fish stock assessment -- South Africa , Fish stock assessment -- Mozambique , Overfishing , Habitat conservation , Fishes -- Genetics , Fishes -- Climatic factors , Fishes -- Variation , Fishes -- Migration
- Description: Chrysoblephus puniceus is an over-exploited linefish species, endemic to the coastlines off southern Mozambique and eastern South Africa. Over-exploitation and habitat loss are two of the biggest threats to the sustainability of fisheries globally. Assessing the genetic stock structure (a prerequisite for effective management) and predicting climate related range changes will provide a better understanding of these threats to C. puniceus which can be used to improve the sustainability of the fishery. Two hundred and eighty four genetic samples were collected from eight sampling sites between Ponta da Barra in Mozambique and Coffee Bay in South Africa. The mitochondrial control region and ten microsatellite loci were amplified to analyse the stock structure of C. puniceus. The majority of microsatellite and mtDNA pairwise population comparisons were not significant (P > 0.05) although Xai Xai and Inhaca populations had some significant population comparisons for mtDNA (P < 0.05). AMOVA did not explain any significant variation at the between groups hierarchical level for any pre-defined groupings except for a mtDNA grouping which separated out Xai Xai and Inhaca from other sampling sites. SAMOVA, isolation by distance tests, structure analysis, principle component analysis and spatial autocorrelation analysis all indicated a single population of C. puniceus as being most likely. The migrate-n analysis provided evidence of current driven larval transport, with net migration rates influenced by current dynamics.Two hundred and thirty six unique presence points of C. puniceus were correlated with seasonal maximum and minimum temperature data and bathymetry to model the current distribution and predict future distribution changes of the species up until 2030. Eight individual species distribution models were developed and combined into a mean ensemble model using the Biomod2 package. Winter minimum temperature was the most important variable in determining models outputs. Overall the ensemble model was accurate with a true skills statistic score of 0.962. Binary transformed mean ensemble models predicted a northern and southern range contraction of C. puniceus' distribution of 15 percent; by 2030. The mean ensemble probability of occurrence models indicated that C. puniceus' abundance is likely to decrease off the southern Mozambique coastline but remain high off KwaZulu-Natal. The results of the genetic analysis support the theory of external recruitment sustaining the KwaZulu Natal fishery for C. puniceus. While the high genetic diversity and connectivity may make C. puniceus more resilient to disturbances, the loss of 15 percent; distribution and 11 percent; genetic diversity by 2030 will increase the species vulnerability. The decrease in abundance of C. puniceus off southern Mozambique together with current widespread exploitation levels could result in the collapse of the fishery. A single transboundary stock of C. puniceus highlights the need for co-management of the species. A combined stock assessment between South Africa and Mozambique and the development of further Marine Protected Areas off southern Mozambique are suggested as management options to minimise the vulnerability of this species.
- Full Text:
- Date Issued: 2014
An exploration of the way in which values and valuing processes might strengthen social learning in water stewardship practices in South Africa
- Authors: Barnes, Garth
- Date: 2014
- Subjects: Integrated water development -- South Africa -- Case studies , Water conservation -- South Africa -- Case studies , Water-supply -- Moral and ethical aspects -- South Africa , Environmental education -- South Africa , Social learning -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1975 , http://hdl.handle.net/10962/d1012940
- Description: This qualitative study, focussing on the way in which values and valuing processes might strengthen social learning in water stewardship practices in South Africa, is located within the broader global narrative that describes the scale of human impact on our Earth systems and that is setting humanity on a trajectory that threatens to place us beyond the safe operating spaces called planetary boundaries. For humanity to live within planetary boundaries – one of which is global freshwater use –will take a new way of relating to the environment called Earth stewardship, which calls for a new ethic of responsibility towards Earth systems. It is at the local level of stewardship within a global approach to water resources management called integrated water resources management that this qualitative study is contextually bound. Two case studies, located in the catchment management forums (CMFs) of the Upper Vaal catchment of Gauteng, South Africa, are used in an exploration of the way in which values and valuing processes might strengthen social learning in water stewardship practices in South Africa. The meta-theory of critical realism is used to help explore this relationship between values, practice and social learning. The study uses document analysis, interviews and observation of selected water stewardship practices to identify held and assigned values, and valuing processes and their influence on social learning, and the framing and de-framing processes that occur in social learning oriented towards water stewardship practices. The study differentiates between held and assigned values and identifies a strong altruistic-held values tendency that characterises forum participants who practice water stewardship in the two case study sites. Most water stewardship practice, identified in the case study sites, manifests as compliance activities in the public – or forum – space, while private-sphere environmentalism is mostly left to the confines of the individual’s private household. Lastly, the CMFs seem to have the potential to provide a space for social learning that is not yet maximised. Drawing from these key findings, the study’s major recommendation is that forums that facilitate learning, either using the current CMF structure or creating new opportunities, need to be provided as a conduit for social learning and reflexivity to make the existing boundaries between private and public forms of water stewardship more porous. This social learning may expand social practice and thus strengthen social change processes that expand water stewardship practices.
- Full Text:
- Date Issued: 2014
- Authors: Barnes, Garth
- Date: 2014
- Subjects: Integrated water development -- South Africa -- Case studies , Water conservation -- South Africa -- Case studies , Water-supply -- Moral and ethical aspects -- South Africa , Environmental education -- South Africa , Social learning -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1975 , http://hdl.handle.net/10962/d1012940
- Description: This qualitative study, focussing on the way in which values and valuing processes might strengthen social learning in water stewardship practices in South Africa, is located within the broader global narrative that describes the scale of human impact on our Earth systems and that is setting humanity on a trajectory that threatens to place us beyond the safe operating spaces called planetary boundaries. For humanity to live within planetary boundaries – one of which is global freshwater use –will take a new way of relating to the environment called Earth stewardship, which calls for a new ethic of responsibility towards Earth systems. It is at the local level of stewardship within a global approach to water resources management called integrated water resources management that this qualitative study is contextually bound. Two case studies, located in the catchment management forums (CMFs) of the Upper Vaal catchment of Gauteng, South Africa, are used in an exploration of the way in which values and valuing processes might strengthen social learning in water stewardship practices in South Africa. The meta-theory of critical realism is used to help explore this relationship between values, practice and social learning. The study uses document analysis, interviews and observation of selected water stewardship practices to identify held and assigned values, and valuing processes and their influence on social learning, and the framing and de-framing processes that occur in social learning oriented towards water stewardship practices. The study differentiates between held and assigned values and identifies a strong altruistic-held values tendency that characterises forum participants who practice water stewardship in the two case study sites. Most water stewardship practice, identified in the case study sites, manifests as compliance activities in the public – or forum – space, while private-sphere environmentalism is mostly left to the confines of the individual’s private household. Lastly, the CMFs seem to have the potential to provide a space for social learning that is not yet maximised. Drawing from these key findings, the study’s major recommendation is that forums that facilitate learning, either using the current CMF structure or creating new opportunities, need to be provided as a conduit for social learning and reflexivity to make the existing boundaries between private and public forms of water stewardship more porous. This social learning may expand social practice and thus strengthen social change processes that expand water stewardship practices.
- Full Text:
- Date Issued: 2014
Lignocellulosic waste degradation using enzyme synergy with commercially available enzymes and Clostridium cellulovorans XylanaseA and MannanaseA
- Authors: Morrison, David Graham
- Date: 2014
- Subjects: Lignocellulose -- Biodegradation , Enzymes -- Biotechnology , Agricultural wastes as fuel , Polysaccharides -- Biotechnology , Sugar -- Inversion , Clostridium , Xylanases , Monomers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4119 , http://hdl.handle.net/10962/d1013292
- Description: The launch of national and international initiatives to reduce pollution, reliance on fossil fuels and increase the beneficiation of agricultural wastes has prompted research into sugar monomer production from lignocellulosic wastes. These sugars can subsequently be used in the production of biofuels and environmentally degradable plastics. This study investigated the use of synergistic combinations of commercial and pure enzymes to lower enzyme costs and loadings, while increasing enzyme activity in the hydrolysis of agricultural waste. Pineapple pomace was selected due to its current underutilisation and the substantial quantities of it produced annually, as a by-product of pineapple canning. One of the primary costs in beneficiating agricultural wastes, such as pineapple pomace, is the high cost of enzyme solutions used to generate reducing sugars. This can be lowered through the use of synergistic combinations of enzymes. Studies related to the inclusion of hemicellulose degrading enzymes with commercial enzyme solutions have been limited and investigation of these solutions in select combinations, together with pineapple pomace substrate, allows for novel research. The use of synergistic combinations of purified cellulosomal enzymes has previously been shown to be effective at releasing reducing sugars from agricultural wastes. For the present study, MannanaseA and XylanaseA from Clostridium cellulovorans were heterologously expressed in Escherichia coli BL21 (DE3) cells and purified with immobilised metal affinity chromatography. These enzymes, in addition to two commercially available enzyme solutions (Celluclast 1.5L® and Pectinex® 3XL), were assayed on defined polysaccharides that are present in pineapple pomace to determine their substrate specificities. The degree(s) of synergy and specific activities of selected combinations of these enzymes were tested under both simultaneous and sequential conditions. It was observed that several synergistic combinations of enzyme solutions in select ratios, such as C20P60X20 (20% cellulose, 60% pectinase and 20% xylanse), C20P40X40 (20% cellulose, 40% pectinase and 40% xylanase) and C20P80 (20% cellulose, 80% pectinase) with pineapple pomace could both decrease the protein loading, while raising the level of activity compared to individual enzyme solutions. The highest quantity of reducing sugars to protein weight used on pineapple pomace was recorded at 3, 9 and 18 hours with combinations of Pectinex® 3XL and Celluclast 1.5L®, but for 27 h it was combinations of both these commercial solutions with XynA. The contribution of XynA was significant as C20P60X20 displayed the second highest reducing sugar production of 1.521 mg/mL, at 36 h from 12.875 μg/mL of protein, which was the second lowest protein loading. It was also shown that certain enzyme combinations, such as Pectinex® 3XL, Celluclast 1.5L® and XynA, did not generate synergy when combined in solution at the initial stages of hydrolysis, and instead generated a form of competition called anti-synergy. This was due to Pectinex® 3XL which had anti-synergy relationships in select combinations with the other enzyme solutions assayed. It was also observed that the degree of synergy and specific activity for a combination changed over time. Some solutions displayed the highest levels of synergy at the commencement of hydrolysis, namely Celluclast 1.5L®, ManA and XynA. Other combinations exhibited the highest levels of synergy at the end of the assay period, such as Pectinex® 3XL and Celluclast 1.5L®. Whether greater synergy was generated at the start or end of hydrolysis was a function of the stability of the enzymes in solution and whether enzyme activity increased substrate accessibility or generated competition between enzymes in solution. Sequential synergy studies demonstrated an anti-synergy relationship between Pectinex® 3XL and XynA or ManA, as well as Pectinex® 3 XL and Celluclast 1.5L®. It was found that under sequential synergy conditions with Pectinex® 3 XL, XynA and ManA, that anti-synergy could be negated and high degrees of synergy attained when the enzymes were added in specific loading orders and not inhibited by the presence of other active enzymes. The importance of loading order was demonstrated under sequential synergy conditions when XynA was added before ManA followed by Pectinex® 3 XL, which increased the activity and synergy of the solution by 50%. This equates to a 60% increase in reducing sugar release from the same concentrations of enzymes and emphasises the importance of removing anti-synergy relationships from combinations of enzymes. It can be concluded that a C20P60X20 combination (based on activity) can both synergistically increase the reducing sugar production and lower the protein loading required for pineapple pomace hydrolysis. This study also highlights the importance of reducing anti-synergy in customised enzyme cocktails and how sequential synergy can demonstrate the order in which a lignocellulosic waste is degraded.
- Full Text:
- Date Issued: 2014
- Authors: Morrison, David Graham
- Date: 2014
- Subjects: Lignocellulose -- Biodegradation , Enzymes -- Biotechnology , Agricultural wastes as fuel , Polysaccharides -- Biotechnology , Sugar -- Inversion , Clostridium , Xylanases , Monomers
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4119 , http://hdl.handle.net/10962/d1013292
- Description: The launch of national and international initiatives to reduce pollution, reliance on fossil fuels and increase the beneficiation of agricultural wastes has prompted research into sugar monomer production from lignocellulosic wastes. These sugars can subsequently be used in the production of biofuels and environmentally degradable plastics. This study investigated the use of synergistic combinations of commercial and pure enzymes to lower enzyme costs and loadings, while increasing enzyme activity in the hydrolysis of agricultural waste. Pineapple pomace was selected due to its current underutilisation and the substantial quantities of it produced annually, as a by-product of pineapple canning. One of the primary costs in beneficiating agricultural wastes, such as pineapple pomace, is the high cost of enzyme solutions used to generate reducing sugars. This can be lowered through the use of synergistic combinations of enzymes. Studies related to the inclusion of hemicellulose degrading enzymes with commercial enzyme solutions have been limited and investigation of these solutions in select combinations, together with pineapple pomace substrate, allows for novel research. The use of synergistic combinations of purified cellulosomal enzymes has previously been shown to be effective at releasing reducing sugars from agricultural wastes. For the present study, MannanaseA and XylanaseA from Clostridium cellulovorans were heterologously expressed in Escherichia coli BL21 (DE3) cells and purified with immobilised metal affinity chromatography. These enzymes, in addition to two commercially available enzyme solutions (Celluclast 1.5L® and Pectinex® 3XL), were assayed on defined polysaccharides that are present in pineapple pomace to determine their substrate specificities. The degree(s) of synergy and specific activities of selected combinations of these enzymes were tested under both simultaneous and sequential conditions. It was observed that several synergistic combinations of enzyme solutions in select ratios, such as C20P60X20 (20% cellulose, 60% pectinase and 20% xylanse), C20P40X40 (20% cellulose, 40% pectinase and 40% xylanase) and C20P80 (20% cellulose, 80% pectinase) with pineapple pomace could both decrease the protein loading, while raising the level of activity compared to individual enzyme solutions. The highest quantity of reducing sugars to protein weight used on pineapple pomace was recorded at 3, 9 and 18 hours with combinations of Pectinex® 3XL and Celluclast 1.5L®, but for 27 h it was combinations of both these commercial solutions with XynA. The contribution of XynA was significant as C20P60X20 displayed the second highest reducing sugar production of 1.521 mg/mL, at 36 h from 12.875 μg/mL of protein, which was the second lowest protein loading. It was also shown that certain enzyme combinations, such as Pectinex® 3XL, Celluclast 1.5L® and XynA, did not generate synergy when combined in solution at the initial stages of hydrolysis, and instead generated a form of competition called anti-synergy. This was due to Pectinex® 3XL which had anti-synergy relationships in select combinations with the other enzyme solutions assayed. It was also observed that the degree of synergy and specific activity for a combination changed over time. Some solutions displayed the highest levels of synergy at the commencement of hydrolysis, namely Celluclast 1.5L®, ManA and XynA. Other combinations exhibited the highest levels of synergy at the end of the assay period, such as Pectinex® 3XL and Celluclast 1.5L®. Whether greater synergy was generated at the start or end of hydrolysis was a function of the stability of the enzymes in solution and whether enzyme activity increased substrate accessibility or generated competition between enzymes in solution. Sequential synergy studies demonstrated an anti-synergy relationship between Pectinex® 3XL and XynA or ManA, as well as Pectinex® 3 XL and Celluclast 1.5L®. It was found that under sequential synergy conditions with Pectinex® 3 XL, XynA and ManA, that anti-synergy could be negated and high degrees of synergy attained when the enzymes were added in specific loading orders and not inhibited by the presence of other active enzymes. The importance of loading order was demonstrated under sequential synergy conditions when XynA was added before ManA followed by Pectinex® 3 XL, which increased the activity and synergy of the solution by 50%. This equates to a 60% increase in reducing sugar release from the same concentrations of enzymes and emphasises the importance of removing anti-synergy relationships from combinations of enzymes. It can be concluded that a C20P60X20 combination (based on activity) can both synergistically increase the reducing sugar production and lower the protein loading required for pineapple pomace hydrolysis. This study also highlights the importance of reducing anti-synergy in customised enzyme cocktails and how sequential synergy can demonstrate the order in which a lignocellulosic waste is degraded.
- Full Text:
- Date Issued: 2014
Geographical variation in effects of nutrient levels and grazing intensity on community structure between upwelling and non-upwelling regions of South Africa
- Authors: Steele, Nikita
- Date: 2014
- Subjects: Upwelling (Oceanography) , Upwelling (Oceanography) -- Indian Ocean , Algae -- Indian Ocean , Algae -- Effect of grazing on -- Indian Ocean
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5873 , http://hdl.handle.net/10962/d1013013
- Description: The aim of this thesis was to assess the influence of upwelling on alga-grazer interactions in rocky shore communities along the south coast of South Africa using grazer exclusion treatments with controls and procedural controls set out in a block design and monitored for algal cover roughly monthly for one year. In the first experiment grazers were excluded from treatment plots at two upwelling and two non-upwelling sites and the rates of algal biomass accumulation were then compared. The upwelling sites showed significantly faster algal colonisation rates, with Ulva rigida being the first species to colonise the rocks. Final algal cover and biomass did not differ significantly between upwelling and non-upwelling sites in control plots open to grazers, but were significantly higher in grazer exclusion plots at upwelling sites indicating stronger grazing effects. This was confirmed by estimating the intensity of grazing using the log-response ratio (LRR), which was calculated from treatment and control plots. Upwelling sites had significantly lower LLR values indicating stronger grazing effects, than at non-upwelling sites, despite no difference in grazer abundances. The second experiment examined the effects of nutrient addition on algal growth and community composition by comparing high nutrient enrichment plots with low enrichment plots at one upwelling and one non-upwelling site. ANOVA indicated faster growth rates and significantly higher final algal biomass in high enrichment plots compared to low enrichment and control plots at both upwelling and non-upwelling sites. A two-way ANOVA indicated significantly higher algal cover in high enrichment plots compared to the data from the grazer exclusion plots in experiment 1 at both sites, suggesting that nutrient addition plays a major role in algal growth and community composition. The findings of these studies have shown significant differences between treatments, sites and seasons, with significant differences not only occurring in algal cover but also accumulation of algal biomass and recruitment patterns between treatments. The small scale local processes acting within a few centimetres (plots) or tens of meters (among blocks) can also be reflected over larger scales such as sites (upwelling/non-upwelling shores). Further, these studies have demonstrated that various factors such as the effects from increased nutrients at upwelling cells and the change in grazing effects due to enhanced nutrients can determine the abundance and diversity of the community structure, including an increase in the abundance of the fast growing algae Ulva rigida, and a slow recovery of the brown and red algae.
- Full Text:
- Date Issued: 2014
- Authors: Steele, Nikita
- Date: 2014
- Subjects: Upwelling (Oceanography) , Upwelling (Oceanography) -- Indian Ocean , Algae -- Indian Ocean , Algae -- Effect of grazing on -- Indian Ocean
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5873 , http://hdl.handle.net/10962/d1013013
- Description: The aim of this thesis was to assess the influence of upwelling on alga-grazer interactions in rocky shore communities along the south coast of South Africa using grazer exclusion treatments with controls and procedural controls set out in a block design and monitored for algal cover roughly monthly for one year. In the first experiment grazers were excluded from treatment plots at two upwelling and two non-upwelling sites and the rates of algal biomass accumulation were then compared. The upwelling sites showed significantly faster algal colonisation rates, with Ulva rigida being the first species to colonise the rocks. Final algal cover and biomass did not differ significantly between upwelling and non-upwelling sites in control plots open to grazers, but were significantly higher in grazer exclusion plots at upwelling sites indicating stronger grazing effects. This was confirmed by estimating the intensity of grazing using the log-response ratio (LRR), which was calculated from treatment and control plots. Upwelling sites had significantly lower LLR values indicating stronger grazing effects, than at non-upwelling sites, despite no difference in grazer abundances. The second experiment examined the effects of nutrient addition on algal growth and community composition by comparing high nutrient enrichment plots with low enrichment plots at one upwelling and one non-upwelling site. ANOVA indicated faster growth rates and significantly higher final algal biomass in high enrichment plots compared to low enrichment and control plots at both upwelling and non-upwelling sites. A two-way ANOVA indicated significantly higher algal cover in high enrichment plots compared to the data from the grazer exclusion plots in experiment 1 at both sites, suggesting that nutrient addition plays a major role in algal growth and community composition. The findings of these studies have shown significant differences between treatments, sites and seasons, with significant differences not only occurring in algal cover but also accumulation of algal biomass and recruitment patterns between treatments. The small scale local processes acting within a few centimetres (plots) or tens of meters (among blocks) can also be reflected over larger scales such as sites (upwelling/non-upwelling shores). Further, these studies have demonstrated that various factors such as the effects from increased nutrients at upwelling cells and the change in grazing effects due to enhanced nutrients can determine the abundance and diversity of the community structure, including an increase in the abundance of the fast growing algae Ulva rigida, and a slow recovery of the brown and red algae.
- Full Text:
- Date Issued: 2014
‘Ubhuti wami’: a qualitative secondary analysis of brothering among isiXhosa men
- Authors: Mbewe, Mpho
- Date: 2014
- Subjects: Brotherliness , Xhosa (African people) -- Social life and customs , Men, Black -- South Africa -- Social life and customs
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3233 , http://hdl.handle.net/10962/d1013149
- Description: This project is interested in investigating the construction of the fraternal sibling relationshipwithin the South African context from a narrative perspective. In particular, this study is interested in the ways in which middle aged isiXhosa men narrate experiences of brothering and how social class, as one particular context, mediates these narratives. This project is particularly interested in brothering within the isiXhosa culture and is concerned with both middle class and working class men within this cultural context. The project takes as its particular focus the meaning of brothering, and specifically how masculinity, intimacy and money or class influence the brothering practices constructed by the men in the sample. The project employs a social constructionist perspective, using a thematic narrative analysis to analyse the data. This project uses secondary analysis of data, as the data was collected for the primary use by Jackson (2009), Peirce (2009), Saville Young (Saville Young & Jackson, 2011) and Stonier (2010). The analysis reflects emergent themes of the importance of fraternal sacrifice, care-taking and sibling responsibility, honouring the family, and challenge to traditional masculinity. These themes emerged within the prior themes of masculinity, intimacy and class within brothering. The men spoke of keeping the family prosperous and united as an important duty in their brothering role. Affection was expressed more practically and symbolically, and closeness constructed through shared experiences, proximity and similarities. My findings reflect that family expectations, culture and social context had key influences on brothering, based on the men's narratives. Findings are discussed in relation to literature on brothering, masculinity and intimacy, and the influence of money in close relationships.
- Full Text:
- Date Issued: 2014
- Authors: Mbewe, Mpho
- Date: 2014
- Subjects: Brotherliness , Xhosa (African people) -- Social life and customs , Men, Black -- South Africa -- Social life and customs
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3233 , http://hdl.handle.net/10962/d1013149
- Description: This project is interested in investigating the construction of the fraternal sibling relationshipwithin the South African context from a narrative perspective. In particular, this study is interested in the ways in which middle aged isiXhosa men narrate experiences of brothering and how social class, as one particular context, mediates these narratives. This project is particularly interested in brothering within the isiXhosa culture and is concerned with both middle class and working class men within this cultural context. The project takes as its particular focus the meaning of brothering, and specifically how masculinity, intimacy and money or class influence the brothering practices constructed by the men in the sample. The project employs a social constructionist perspective, using a thematic narrative analysis to analyse the data. This project uses secondary analysis of data, as the data was collected for the primary use by Jackson (2009), Peirce (2009), Saville Young (Saville Young & Jackson, 2011) and Stonier (2010). The analysis reflects emergent themes of the importance of fraternal sacrifice, care-taking and sibling responsibility, honouring the family, and challenge to traditional masculinity. These themes emerged within the prior themes of masculinity, intimacy and class within brothering. The men spoke of keeping the family prosperous and united as an important duty in their brothering role. Affection was expressed more practically and symbolically, and closeness constructed through shared experiences, proximity and similarities. My findings reflect that family expectations, culture and social context had key influences on brothering, based on the men's narratives. Findings are discussed in relation to literature on brothering, masculinity and intimacy, and the influence of money in close relationships.
- Full Text:
- Date Issued: 2014
Exploratory study : how do Somali shop owners (SSO) succeed in running businesses in Soweto : a South African perspective
- Authors: Mokitlane, Ofentse Clifford
- Date: 2014
- Subjects: Business enterprises, Foreign -- South Africa , Small business -- Management , Small business -- South Africa , Foreign workers -- South Africa , Employment in foreign countries , Entrepreneurship -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:842 , http://hdl.handle.net/10962/d1015653
- Description: This is a qualitative study which seeks to understand how Somali shop owners run successful businesses in the township of Soweto in South Africa. This research report has three sections, namely (1) the academic paper which comprises a shortened literature review, the research method, findings, and the discussion; (2) an extended literature review and (3) the research methodology. It is important to mention that these three sections are related and not necessarily stand-alone sections. Despite the hostilities faced by the Somali shop owners from the host communities in South Africa, it is notable that they are successful, small-sized entrepreneurs in most townships of South Africa (SA). Previous research on Somalis has predominantly focused on their assimilation into the societies in their host countries, and on how they are led into self-employment because of the unfavourable labour markets in the host country. In this vein, there is a need to understand how they run successful businesses in the townships of SA. This study seeks to answer the following research question: How Do Somali Shop Owners Succeed in Running Businesses in Soweto, South Africa (SA)? In pursuit of answers to the above research question, this study was confined to three locations in Soweto, namely Orlando West, Chiawelo and Rockville which have a relatively high number of Somali entrepreneurs who have been in operation for longer than three years. This qualitative study explored the multiple perspectives of reality of Somali shop owners. Purposively, 14 Somali shop owners were identified initially using purposive sampling. Subsequently, theoretical sampling was used to identify Somali shop owners who were interviewed regarding how they successfully run their businesses in the locations of Orlando West, Chiawelo and Rockville in the township of Soweto. A total of eighteen semi-structured, in-depth and face-to-face interviews were conducted with these shop owners as a means of gathering data to the point of saturating their perspectives. Data collection ceased when new perspectives were no longer evident as interviewees were being repetitive. Open-coding and constant comparison was used to analyse the data. The findings of the study show that ethnicity plays a predominant role in the success of the Somali shop owners. The intra-ethnic networks and trust-based support systems are pivotal to how Somali shop owners run successful businesses in Soweto. The key findings manifested showed that various forms of support came from Somali communities, family and fellow countrymen which were also central to their success. Another key finding showed that Somali shop owners run their businesses by complementing, rather than predominantly competing with the other local businesses, which ultimately differentiates them in this way. The study also revealed that responsiveness to local customer needs by enhancing the value of their business to the locality is also characteristic of how Somali shop owners build customer loyalty. This study contributes to our understanding of how Somali entrepreneurs conduct successful businesses in a hostile host country. The findings have implications for business development training and programmes which support immigrant entrepreneurs. The findings may also be extended to inform how business development programmes would be designed to equally support local entrepreneurs.
- Full Text:
- Date Issued: 2014
- Authors: Mokitlane, Ofentse Clifford
- Date: 2014
- Subjects: Business enterprises, Foreign -- South Africa , Small business -- Management , Small business -- South Africa , Foreign workers -- South Africa , Employment in foreign countries , Entrepreneurship -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:842 , http://hdl.handle.net/10962/d1015653
- Description: This is a qualitative study which seeks to understand how Somali shop owners run successful businesses in the township of Soweto in South Africa. This research report has three sections, namely (1) the academic paper which comprises a shortened literature review, the research method, findings, and the discussion; (2) an extended literature review and (3) the research methodology. It is important to mention that these three sections are related and not necessarily stand-alone sections. Despite the hostilities faced by the Somali shop owners from the host communities in South Africa, it is notable that they are successful, small-sized entrepreneurs in most townships of South Africa (SA). Previous research on Somalis has predominantly focused on their assimilation into the societies in their host countries, and on how they are led into self-employment because of the unfavourable labour markets in the host country. In this vein, there is a need to understand how they run successful businesses in the townships of SA. This study seeks to answer the following research question: How Do Somali Shop Owners Succeed in Running Businesses in Soweto, South Africa (SA)? In pursuit of answers to the above research question, this study was confined to three locations in Soweto, namely Orlando West, Chiawelo and Rockville which have a relatively high number of Somali entrepreneurs who have been in operation for longer than three years. This qualitative study explored the multiple perspectives of reality of Somali shop owners. Purposively, 14 Somali shop owners were identified initially using purposive sampling. Subsequently, theoretical sampling was used to identify Somali shop owners who were interviewed regarding how they successfully run their businesses in the locations of Orlando West, Chiawelo and Rockville in the township of Soweto. A total of eighteen semi-structured, in-depth and face-to-face interviews were conducted with these shop owners as a means of gathering data to the point of saturating their perspectives. Data collection ceased when new perspectives were no longer evident as interviewees were being repetitive. Open-coding and constant comparison was used to analyse the data. The findings of the study show that ethnicity plays a predominant role in the success of the Somali shop owners. The intra-ethnic networks and trust-based support systems are pivotal to how Somali shop owners run successful businesses in Soweto. The key findings manifested showed that various forms of support came from Somali communities, family and fellow countrymen which were also central to their success. Another key finding showed that Somali shop owners run their businesses by complementing, rather than predominantly competing with the other local businesses, which ultimately differentiates them in this way. The study also revealed that responsiveness to local customer needs by enhancing the value of their business to the locality is also characteristic of how Somali shop owners build customer loyalty. This study contributes to our understanding of how Somali entrepreneurs conduct successful businesses in a hostile host country. The findings have implications for business development training and programmes which support immigrant entrepreneurs. The findings may also be extended to inform how business development programmes would be designed to equally support local entrepreneurs.
- Full Text:
- Date Issued: 2014
Toward a culture of engagement: leveraging the enterprise social network
- Authors: Alistoun, Garth
- Date: 2014
- Subjects: Communication in organizations -- South Africa Business communication -- South Africa Social media -- South Africa -- Case studies Leadership -- South Africa -- Case studies Human capital -- Management Personnel management Organizational effectiveness
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1154 , http://hdl.handle.net/10962/d1010869
- Description: This research aims to provide a theory of enterprise social networking that generates and/or sustains a culture of employee engagement within a chosen South African private sector company. Based on an extensive review of interesting literature and the application of a grounded theory process in a chosen case, this research work provides a theory of enterprise social networking sustaining and growing employee engagement together with an explanatory theoretical framework that makes the theory more practical. Employee engagement is defined as “the harnessing of organisation member’s selves to their work roles; in engagement people employ and express themselves physically, cognitively, and emotionally during role performances.” This research regards employee engagement as a three part concept composed of a trait (personality/cognitive) aspect, a state (emotional) aspect, and a behavioural aspect. Research has shown that employee engagement has an unequivocal positive impact on business outcomes, such as profitability, business performance, employee retention and productivity. Employee engagement can be regarded as a culture if it is abundant within the organization’s employee population. Gatenby et al. (2009) propose that employee engagement is fostered by creating the desire and opportunity for employees to connect with colleagues, managers and the wider organisation. This standpoint is supported by Kular et al. (2008) who state that the “key drivers of employee engagement identified include communication, opportunities for employees to feed their views upward and thinking that their managers are committed to the organisation.” Further indicators of employee engagement include strong leadership (particularly in the form of servant leadership), accountability, a positive and open organisational culture, autonomy, and opportunities for development. One of the key facets of employee engagement is connection. A complementary definition of social media, an umbrella under which enterprise social networks fall, is that “(it) is more of a relationship channel, a connection channel. Each and every tweet, update, video, post, is a connection point to another human being. And it’s the other human being who will determine your worth to them.” Social media provides participants with access to a larger pool of resources and relationships than they would normally have access to. This enlarged relationship/resource pool is a result of expanding human and social capital enabled through social media tools. In order to produce a theory of enterprise social networking sustaining and growing a culture of employee engagement a rigorous grounded theory methodology coupled with a case study methodology was applied. The case study methodology was used to identify a suitable research site and interesting participants within the site while the grounded theory process was used to produce both qualitative and quantitative data sets in a suitability rigorous fashion. The corroborative data was then used to discover and define the emergent theory.
- Full Text:
- Date Issued: 2014
- Authors: Alistoun, Garth
- Date: 2014
- Subjects: Communication in organizations -- South Africa Business communication -- South Africa Social media -- South Africa -- Case studies Leadership -- South Africa -- Case studies Human capital -- Management Personnel management Organizational effectiveness
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1154 , http://hdl.handle.net/10962/d1010869
- Description: This research aims to provide a theory of enterprise social networking that generates and/or sustains a culture of employee engagement within a chosen South African private sector company. Based on an extensive review of interesting literature and the application of a grounded theory process in a chosen case, this research work provides a theory of enterprise social networking sustaining and growing employee engagement together with an explanatory theoretical framework that makes the theory more practical. Employee engagement is defined as “the harnessing of organisation member’s selves to their work roles; in engagement people employ and express themselves physically, cognitively, and emotionally during role performances.” This research regards employee engagement as a three part concept composed of a trait (personality/cognitive) aspect, a state (emotional) aspect, and a behavioural aspect. Research has shown that employee engagement has an unequivocal positive impact on business outcomes, such as profitability, business performance, employee retention and productivity. Employee engagement can be regarded as a culture if it is abundant within the organization’s employee population. Gatenby et al. (2009) propose that employee engagement is fostered by creating the desire and opportunity for employees to connect with colleagues, managers and the wider organisation. This standpoint is supported by Kular et al. (2008) who state that the “key drivers of employee engagement identified include communication, opportunities for employees to feed their views upward and thinking that their managers are committed to the organisation.” Further indicators of employee engagement include strong leadership (particularly in the form of servant leadership), accountability, a positive and open organisational culture, autonomy, and opportunities for development. One of the key facets of employee engagement is connection. A complementary definition of social media, an umbrella under which enterprise social networks fall, is that “(it) is more of a relationship channel, a connection channel. Each and every tweet, update, video, post, is a connection point to another human being. And it’s the other human being who will determine your worth to them.” Social media provides participants with access to a larger pool of resources and relationships than they would normally have access to. This enlarged relationship/resource pool is a result of expanding human and social capital enabled through social media tools. In order to produce a theory of enterprise social networking sustaining and growing a culture of employee engagement a rigorous grounded theory methodology coupled with a case study methodology was applied. The case study methodology was used to identify a suitable research site and interesting participants within the site while the grounded theory process was used to produce both qualitative and quantitative data sets in a suitability rigorous fashion. The corroborative data was then used to discover and define the emergent theory.
- Full Text:
- Date Issued: 2014
Facilitating and renegotiating Afrikaans youth identities: Die Antwoord phenomenon
- Authors: Meintjes, Stephané Ruth
- Date: 2014
- Subjects: Die Antwoord , Die Antwoord -- I Fink U Freeky , Identity (Psychology) -- Social aspects , Afrikaner nationalism , Afrikaners -- Ethnic identity , Afrikaners -- Psychology , South Africa -- Race relations , Music, Influence of -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3538 , http://hdl.handle.net/10962/d1015655
- Description: This thesis reports on a project which investigated how young native, Afrikaans-speaking Rhodes University students responded to the musical outfit Die Antwoord and to their music video “I Fink U Freeky”. The study attempted to establish how a selected group of Afrikaans-speaking students consisting of Whites, Coloureds and Blacks interpret the work of Die Antwoord as well as their own Afrikaans identity. The purpose of the study was to interrogate the relationship between artistic media, citizenship and belonging to a particular group. The thesis reports on the ways in which interviewees in the group discussions responded to notions of identity, whiteness, class, race, hybridity and creolization registered in the music video which was used to prompt the discussions. Finally the thesis reports on findings regarding the relationship between citizenship and the artistic media. The enormous change in the socio-political position of Afrikaans-speakers in the post -1994 dispensation provides the social context of the study. The project utilised qualitative research and a reception study of the music was undertaken by means of focus group discussions in order to arrive at thick descriptions in an attempt to understand the contextual behaviour of the participants. It was postulated that Die Antwoord provides a discursive site within which audiences could generate their own innovative meanings regarding being Afrikaans. While there was no clear indication that the identities of the participants was constructed by the media, the video prompted discussions regarding identity and provided evidence that media texts are capable of stimulating an interrogation of identities. It emerged that all participants, while abandoning some aspects of Afrikaans culture, strongly embraced and highly valued the language. Participants did not regard race as an important aspect of citizenship. Vociferous discussions regarding class demonstrated how media texts can influence citizenship. Discussions about hybridization and creolization demonstrated how the media can challenge received conceptions regarding citizenship. Responses provided evidence that the media could stimulate new forms of citizenship and contribute to the inclusion of previously excluded subjects. The research findings clearly demonstrate links between artistic media, citizenship and belonging to a group of Afrikaanses rather than Afrikaners. Post- 1994 young Afrikaans-speakers in this study provided clear evidence that they are exploring new and alternative ways of being Afrikaans.
- Full Text:
- Date Issued: 2014
- Authors: Meintjes, Stephané Ruth
- Date: 2014
- Subjects: Die Antwoord , Die Antwoord -- I Fink U Freeky , Identity (Psychology) -- Social aspects , Afrikaner nationalism , Afrikaners -- Ethnic identity , Afrikaners -- Psychology , South Africa -- Race relations , Music, Influence of -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3538 , http://hdl.handle.net/10962/d1015655
- Description: This thesis reports on a project which investigated how young native, Afrikaans-speaking Rhodes University students responded to the musical outfit Die Antwoord and to their music video “I Fink U Freeky”. The study attempted to establish how a selected group of Afrikaans-speaking students consisting of Whites, Coloureds and Blacks interpret the work of Die Antwoord as well as their own Afrikaans identity. The purpose of the study was to interrogate the relationship between artistic media, citizenship and belonging to a particular group. The thesis reports on the ways in which interviewees in the group discussions responded to notions of identity, whiteness, class, race, hybridity and creolization registered in the music video which was used to prompt the discussions. Finally the thesis reports on findings regarding the relationship between citizenship and the artistic media. The enormous change in the socio-political position of Afrikaans-speakers in the post -1994 dispensation provides the social context of the study. The project utilised qualitative research and a reception study of the music was undertaken by means of focus group discussions in order to arrive at thick descriptions in an attempt to understand the contextual behaviour of the participants. It was postulated that Die Antwoord provides a discursive site within which audiences could generate their own innovative meanings regarding being Afrikaans. While there was no clear indication that the identities of the participants was constructed by the media, the video prompted discussions regarding identity and provided evidence that media texts are capable of stimulating an interrogation of identities. It emerged that all participants, while abandoning some aspects of Afrikaans culture, strongly embraced and highly valued the language. Participants did not regard race as an important aspect of citizenship. Vociferous discussions regarding class demonstrated how media texts can influence citizenship. Discussions about hybridization and creolization demonstrated how the media can challenge received conceptions regarding citizenship. Responses provided evidence that the media could stimulate new forms of citizenship and contribute to the inclusion of previously excluded subjects. The research findings clearly demonstrate links between artistic media, citizenship and belonging to a group of Afrikaanses rather than Afrikaners. Post- 1994 young Afrikaans-speakers in this study provided clear evidence that they are exploring new and alternative ways of being Afrikaans.
- Full Text:
- Date Issued: 2014
The characterisation of an openwork block deposit, northern buttress, Vesleskarvet, Dronning Maud Land, Antarctica.
- Authors: Hansen, Christel Dorothee
- Date: 2014
- Subjects: Formations (Geology) -- Antarctica -- Queen Maud Land , Geology, Structural -- Antarctica -- Queen Maud Land , Weathering -- Antarctica -- Queen Maud Land , Climatic changes -- Antarctica -- Queen Maud Land , Physical geography -- Antarctica -- Queen Maud Land , Paleoclimatology -- Antarctica
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4878 , http://hdl.handle.net/10962/d1013138
- Description: Investigating openwork block accumulation has the potential to further our understanding of rock weathering, the control of geological structure on landforms, the production of substrates for biological colonisation and the impacts of climate change on landform development and dynamics. Various models for the development of these landforms have been proposed. This includes in situ weathering, frost heave and wedging. Furthermore, it has been suggested that cold-based ice has the potential to preserve these features rather than to obliterate them. Blocky deposits are also frequently used as proxy evidence for interpreting palaeoclimates. The morphology and processes acting on a blockfield located on the Northern Buttress of the Vesleskarvet Nunataks, Dronning Maud Land, Antarctica (2°W, 71°S) were investigated and characterised. Given block dimensions and orientations that closely resembled the parent material and only small differences in aspect related characteristics observed, the blockfield was found to be autochthonous with in situ block production and of a young (Holocene) age. Small differences in rock hardness measurements suggest some form of aspect control on rock weathering. South-facing sides of clasts were found to be the least weathered. In comparison, consistently low rock hardness rebound values for the north-facing aspects suggest that these are the most weathered sides. Additional indicators of weathering, such as flaking and pitting, support analyses conducted for rock hardness rebound values. Solar radiation received, slope gradients and snow cover were found to influence weathering of clasts across the study site. Furthermore, ambient temperatures and wind speed significantly influenced near-surface ground temperatures dynamics. However, the lack of a matrix and paucity of fine material in textural analyses suggest a limited weathering environment. It is suggested that the retreat of the Antarctic ice sheet during the last LGM led to unloading of the surface, causing dilatation and subsequent fracturing of the bedrock along pre-existing joints, leading to in situ clast supply. Subsequent weathering and erosion along other points or lines of weakness then yielded fines and slight edge rounding of clasts.
- Full Text:
- Date Issued: 2014
- Authors: Hansen, Christel Dorothee
- Date: 2014
- Subjects: Formations (Geology) -- Antarctica -- Queen Maud Land , Geology, Structural -- Antarctica -- Queen Maud Land , Weathering -- Antarctica -- Queen Maud Land , Climatic changes -- Antarctica -- Queen Maud Land , Physical geography -- Antarctica -- Queen Maud Land , Paleoclimatology -- Antarctica
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4878 , http://hdl.handle.net/10962/d1013138
- Description: Investigating openwork block accumulation has the potential to further our understanding of rock weathering, the control of geological structure on landforms, the production of substrates for biological colonisation and the impacts of climate change on landform development and dynamics. Various models for the development of these landforms have been proposed. This includes in situ weathering, frost heave and wedging. Furthermore, it has been suggested that cold-based ice has the potential to preserve these features rather than to obliterate them. Blocky deposits are also frequently used as proxy evidence for interpreting palaeoclimates. The morphology and processes acting on a blockfield located on the Northern Buttress of the Vesleskarvet Nunataks, Dronning Maud Land, Antarctica (2°W, 71°S) were investigated and characterised. Given block dimensions and orientations that closely resembled the parent material and only small differences in aspect related characteristics observed, the blockfield was found to be autochthonous with in situ block production and of a young (Holocene) age. Small differences in rock hardness measurements suggest some form of aspect control on rock weathering. South-facing sides of clasts were found to be the least weathered. In comparison, consistently low rock hardness rebound values for the north-facing aspects suggest that these are the most weathered sides. Additional indicators of weathering, such as flaking and pitting, support analyses conducted for rock hardness rebound values. Solar radiation received, slope gradients and snow cover were found to influence weathering of clasts across the study site. Furthermore, ambient temperatures and wind speed significantly influenced near-surface ground temperatures dynamics. However, the lack of a matrix and paucity of fine material in textural analyses suggest a limited weathering environment. It is suggested that the retreat of the Antarctic ice sheet during the last LGM led to unloading of the surface, causing dilatation and subsequent fracturing of the bedrock along pre-existing joints, leading to in situ clast supply. Subsequent weathering and erosion along other points or lines of weakness then yielded fines and slight edge rounding of clasts.
- Full Text:
- Date Issued: 2014
Road to redemption
- Authors: Singh, Anirood
- Date: 2014
- Subjects: Creative writing (Higher education) -- Research -- South Africa , Creative writing -- Fiction , South African fiction (English) -- Study and teaching (Higher) , South African fiction (English) -- 21st century , Detective and mystery stories, South African (English)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5977 , http://hdl.handle.net/10962/d1013035
- Description: Lurching from day-today in the months before South Africa becomes a republic, booze-befuddled Indian private investigator Rohit Biswas does not ponder how he can secure his daughter's future after he became a widower and lost his job as police detective when he killed a man who fatally stabbed his wife. Salvation appears when a rich client hires the PI to find evidence proving his son did not rape and murder a white socialite. Fighting against seeming impossible odds in colonial-apartheid Durban and a sanctions-busting conspiracy, Biswas secures his client's acquittal. In the process he defies karma and redeems himself.
- Full Text:
- Date Issued: 2014
- Authors: Singh, Anirood
- Date: 2014
- Subjects: Creative writing (Higher education) -- Research -- South Africa , Creative writing -- Fiction , South African fiction (English) -- Study and teaching (Higher) , South African fiction (English) -- 21st century , Detective and mystery stories, South African (English)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5977 , http://hdl.handle.net/10962/d1013035
- Description: Lurching from day-today in the months before South Africa becomes a republic, booze-befuddled Indian private investigator Rohit Biswas does not ponder how he can secure his daughter's future after he became a widower and lost his job as police detective when he killed a man who fatally stabbed his wife. Salvation appears when a rich client hires the PI to find evidence proving his son did not rape and murder a white socialite. Fighting against seeming impossible odds in colonial-apartheid Durban and a sanctions-busting conspiracy, Biswas secures his client's acquittal. In the process he defies karma and redeems himself.
- Full Text:
- Date Issued: 2014
Genetic and biological characterisation of a novel South African Plutella xylostella granulovirus (PlxyGV) isolate
- Authors: Abdulkadir, Fatima
- Date: 2014
- Subjects: Diamondback moth , Diamondback moth -- Control -- South Africa , Plutellidae -- Control -- South Africa , Baculoviruses , Cruciferae -- Diseases and pests -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4113 , http://hdl.handle.net/10962/d1013059
- Description: The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is an important pest of cruciferous crops worldwide. The prolonged use of synthetic chemical insecticides as a primary means of control has resulted in the development of resistance in pest populations. In addition, the pest has also evolved resistance to the bacterial insecticidal protein of Bacillus thuringiensis which is also widely used as a method of control. Baculoviruses are considered as effective alternatives to conventional methods of control when incorporated into integrated pest management (IPM) programmes. These viruses target the larval stages of insects, are generally host-specific and are safe for use in the environment. This study aimed to isolate a baculovirus from a laboratory-reared P. xylostella colony, characterise it genetically and then evaluate its virulence against neonate and fourth instar larvae. A laboratory colony of P. xylostella was established using pupae and asymptomatic larvae collected from a cabbage plantation outside Grahamstown in the Eastern Cape province of South Africa. The colony flourished in the laboratory due to prime conditions and availability of food. The duration of development from egg to adult was determined by observation and imaging of the various life stages. The mean developmental time from egg to adult was observed to be 14.59 ± 0.21 days. The population of the insects increased rapidly in number leading to overcrowding of the insect colony, and hence appearance of larvae with viral symptoms. Occlusion bodies (OBs) were extracted from symptomatic larval cadavers and purified by glycerol gradient centrifugation. Analysis of the purified OBs by transmission electron microscopy revealed the presence of a granulovirus which was named PlxyGV-SA. The virus isolate was genetically characterised by restriction endonuclease analysis of the genomic DNA, and PCR amplification and sequencing of selected viral genes. The complete genome sequence of a Japanese P. xylostella granulovirus isolate, PlxyGV-Japan, has been deposited on the GenBank database providing a reference strain for comparison with DNA profiles and selected gene sequences of PlxyGV-SA. BLAST analysis of the granulin gene confirmed the isolation of a novel South African PlxyGV isolate. Comparison of the restriction profiles of PlxyGV-SA with profiles of PlxyGV-Japan and other documented PlxyGV profiles obtained by agarose gel electrophoresis revealed that PlxyGV-SA is a genetically distinct isolate. The data obtained from the sequencing and alignment of ecdysteroid UDP-glucosyltransferase (egt), late expression factor 8 (lef-8) and late expression factor 9 (lef-9) genes with those of PlxyGV-Japan also showed that PlxyGV-SA is a genetically different isolate. In order to determine the biological activity of PlxyGV-SA against neonate and fourth instar P. xylostella larvae, surface dose bioassays were conducted. The median lethal concentration of the virus required to kill 50% (LC₅₀) and 90% (LC₉₀) of the larvae was estimated by feeding insects with a range of doses. In addition, the time to kill 50% of the larvae (LT₅₀) was determined by feeding insects with the LC₉₀ concentration. Larval mortality was monitored daily until pupation. The data obtained from the dose response assays were subjected to probit analysis using Proban statistical software. The time response was determined using GraphPad Prism software (version 6.0). The LC₅₀ and LC₉₀ values for the neonate larvae were 3.56 × 10⁵ and 1.14 × 10⁷ OBs/ml respectively. The LT₅₀ was determined to be 104 hours. The neonate larvae were found to be more susceptible to infection than the fourth instar larvae with the same virus concentration. The concentrations used for the neonate larvae assay did not have a significant effect on the fourth instar as no mortality was recorded. This is the first study to describe a novel South African PlxyGV isolate and the results suggest that PlxyGV-SA has significant potential for development as an effective biopesticide for the control of P. xylostella in the field.
- Full Text:
- Date Issued: 2014
- Authors: Abdulkadir, Fatima
- Date: 2014
- Subjects: Diamondback moth , Diamondback moth -- Control -- South Africa , Plutellidae -- Control -- South Africa , Baculoviruses , Cruciferae -- Diseases and pests -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4113 , http://hdl.handle.net/10962/d1013059
- Description: The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is an important pest of cruciferous crops worldwide. The prolonged use of synthetic chemical insecticides as a primary means of control has resulted in the development of resistance in pest populations. In addition, the pest has also evolved resistance to the bacterial insecticidal protein of Bacillus thuringiensis which is also widely used as a method of control. Baculoviruses are considered as effective alternatives to conventional methods of control when incorporated into integrated pest management (IPM) programmes. These viruses target the larval stages of insects, are generally host-specific and are safe for use in the environment. This study aimed to isolate a baculovirus from a laboratory-reared P. xylostella colony, characterise it genetically and then evaluate its virulence against neonate and fourth instar larvae. A laboratory colony of P. xylostella was established using pupae and asymptomatic larvae collected from a cabbage plantation outside Grahamstown in the Eastern Cape province of South Africa. The colony flourished in the laboratory due to prime conditions and availability of food. The duration of development from egg to adult was determined by observation and imaging of the various life stages. The mean developmental time from egg to adult was observed to be 14.59 ± 0.21 days. The population of the insects increased rapidly in number leading to overcrowding of the insect colony, and hence appearance of larvae with viral symptoms. Occlusion bodies (OBs) were extracted from symptomatic larval cadavers and purified by glycerol gradient centrifugation. Analysis of the purified OBs by transmission electron microscopy revealed the presence of a granulovirus which was named PlxyGV-SA. The virus isolate was genetically characterised by restriction endonuclease analysis of the genomic DNA, and PCR amplification and sequencing of selected viral genes. The complete genome sequence of a Japanese P. xylostella granulovirus isolate, PlxyGV-Japan, has been deposited on the GenBank database providing a reference strain for comparison with DNA profiles and selected gene sequences of PlxyGV-SA. BLAST analysis of the granulin gene confirmed the isolation of a novel South African PlxyGV isolate. Comparison of the restriction profiles of PlxyGV-SA with profiles of PlxyGV-Japan and other documented PlxyGV profiles obtained by agarose gel electrophoresis revealed that PlxyGV-SA is a genetically distinct isolate. The data obtained from the sequencing and alignment of ecdysteroid UDP-glucosyltransferase (egt), late expression factor 8 (lef-8) and late expression factor 9 (lef-9) genes with those of PlxyGV-Japan also showed that PlxyGV-SA is a genetically different isolate. In order to determine the biological activity of PlxyGV-SA against neonate and fourth instar P. xylostella larvae, surface dose bioassays were conducted. The median lethal concentration of the virus required to kill 50% (LC₅₀) and 90% (LC₉₀) of the larvae was estimated by feeding insects with a range of doses. In addition, the time to kill 50% of the larvae (LT₅₀) was determined by feeding insects with the LC₉₀ concentration. Larval mortality was monitored daily until pupation. The data obtained from the dose response assays were subjected to probit analysis using Proban statistical software. The time response was determined using GraphPad Prism software (version 6.0). The LC₅₀ and LC₉₀ values for the neonate larvae were 3.56 × 10⁵ and 1.14 × 10⁷ OBs/ml respectively. The LT₅₀ was determined to be 104 hours. The neonate larvae were found to be more susceptible to infection than the fourth instar larvae with the same virus concentration. The concentrations used for the neonate larvae assay did not have a significant effect on the fourth instar as no mortality was recorded. This is the first study to describe a novel South African PlxyGV isolate and the results suggest that PlxyGV-SA has significant potential for development as an effective biopesticide for the control of P. xylostella in the field.
- Full Text:
- Date Issued: 2014
Grieving forests
- Authors: Bila, Freddy Vonani
- Date: 2014
- Subjects: Creative writing (Higher education) -- Research -- South Africa , Creative writing -- Poetry , South African poetry (English) -- Study and teaching (Higher) , South African poetry (English) -- 21st century , English language -- Writing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5997 , http://hdl.handle.net/10962/d1020880
- Description: This is a collection of village narrative poems mainly set in rural Limpopo that searches into the complexity of the past and how historical events impact on the present. Although the poems are imagined along the Marxist dialectic, they’re fresh imaginative creations featuring a strong element of surprise, spiritual mysticism, experimenting with form, delving into unknown poetic avenues, creating new music, exploring new sounds and taking risks. The long and intense poem, Ancestral wealth, which is a tribute to the poet’s father, reflects on death and its impact through the effective application of various stylistic elements and poetic devices, thus immortalising the life of a rural South African. Overall the poems, including retrospective and experimental ones, condemn the free market economic system and all that it seems to necessitate: the degradation of ecology, indifference to human suffering and the alienation of vulnerable social groups.
- Full Text:
- Date Issued: 2014
- Authors: Bila, Freddy Vonani
- Date: 2014
- Subjects: Creative writing (Higher education) -- Research -- South Africa , Creative writing -- Poetry , South African poetry (English) -- Study and teaching (Higher) , South African poetry (English) -- 21st century , English language -- Writing
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:5997 , http://hdl.handle.net/10962/d1020880
- Description: This is a collection of village narrative poems mainly set in rural Limpopo that searches into the complexity of the past and how historical events impact on the present. Although the poems are imagined along the Marxist dialectic, they’re fresh imaginative creations featuring a strong element of surprise, spiritual mysticism, experimenting with form, delving into unknown poetic avenues, creating new music, exploring new sounds and taking risks. The long and intense poem, Ancestral wealth, which is a tribute to the poet’s father, reflects on death and its impact through the effective application of various stylistic elements and poetic devices, thus immortalising the life of a rural South African. Overall the poems, including retrospective and experimental ones, condemn the free market economic system and all that it seems to necessitate: the degradation of ecology, indifference to human suffering and the alienation of vulnerable social groups.
- Full Text:
- Date Issued: 2014