Agathis bishopi (Nixon) (Hymenoptera: braconidae) its biology and usefulness as a biological control agent for false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: tortricidae), on citrus bishopi (Nixon) (Hymenoptera: braconidae) its biology and usefulness as a biological control agent for false codling moth (FCM), Thaumatotibia leucotreta (Meyrick) (Lepidoptera: tortricidae), on citrus
- Authors: Gendall, Kierryn Leigh
- Date: 2008
- Subjects: Cryptophlebia leucotreta -- Parasites , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Tortricidae , Braconidae , Citrus -- Diseases and pests
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5635 , http://hdl.handle.net/10962/d1005317 , Cryptophlebia leucotreta -- Parasites , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Tortricidae , Braconidae , Citrus -- Diseases and pests
- Description: The false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), is one of the major pests of citrus in South Africa, the others being mealybug, Mediterranean fruit fly, bollworm and some mites. Due to problems such as the expense of pesticides, insects evolving pesticide resistance (Hogsette 1999), chemical residue on the skin of export fruit and the negative impact of pesticides on the environment, it became necessary to find alternative methods for pest control (Viggiani 2000). Agathis bishopi (Nixon) (Hymenoptera: Braconidae), a larval parasitoid of false codling moth known only from the Sundays River Valley area (Sishuba 2003), offers a means of control for the pest. A total of 11 389 navel oranges were collected from various orchards in the Addo/Kirkwood area, and false codling moth larvae infested 36.09% of the fruit. A single parasitoid species, A. bishopi, was reared from these larvae. In 2006 the highest parasitism rate, 11.43%, was recorded in May and in 2007, the highest parasitism rate, 13.27%, was in April. Agathis bishopi parasitizes larvae in instars 2 and 3, possibly due to the accessibility of these younger instars to the female parasitoid and possibly due to the length of the life cycle of this koinobiont. Second instar hosts yielded the highest number of parasitoids, and there was no emergence of parasitoids from fifth instar larvae. Females of A. bishopi live for 18.5 days (n = 20; S.E. = 3.1) and males for 8.25 days (n = 20; S.E. = 1.23). Females produce an average of 23 offspring in a lifetime, while female false codling moths produce about 800 eggs each. A high number of parasitoids will be required per hectare to reduce the population of false codling moth. Captive rearing of A. bishopi proved difficult due to viral and fungal contamination. Agathis bishopi has potential for use in an integrated pest management programme once the hurdle of mass-rearing has been overcome.
- Full Text:
- Date Issued: 2008
- Authors: Gendall, Kierryn Leigh
- Date: 2008
- Subjects: Cryptophlebia leucotreta -- Parasites , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Tortricidae , Braconidae , Citrus -- Diseases and pests
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5635 , http://hdl.handle.net/10962/d1005317 , Cryptophlebia leucotreta -- Parasites , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Tortricidae , Braconidae , Citrus -- Diseases and pests
- Description: The false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), is one of the major pests of citrus in South Africa, the others being mealybug, Mediterranean fruit fly, bollworm and some mites. Due to problems such as the expense of pesticides, insects evolving pesticide resistance (Hogsette 1999), chemical residue on the skin of export fruit and the negative impact of pesticides on the environment, it became necessary to find alternative methods for pest control (Viggiani 2000). Agathis bishopi (Nixon) (Hymenoptera: Braconidae), a larval parasitoid of false codling moth known only from the Sundays River Valley area (Sishuba 2003), offers a means of control for the pest. A total of 11 389 navel oranges were collected from various orchards in the Addo/Kirkwood area, and false codling moth larvae infested 36.09% of the fruit. A single parasitoid species, A. bishopi, was reared from these larvae. In 2006 the highest parasitism rate, 11.43%, was recorded in May and in 2007, the highest parasitism rate, 13.27%, was in April. Agathis bishopi parasitizes larvae in instars 2 and 3, possibly due to the accessibility of these younger instars to the female parasitoid and possibly due to the length of the life cycle of this koinobiont. Second instar hosts yielded the highest number of parasitoids, and there was no emergence of parasitoids from fifth instar larvae. Females of A. bishopi live for 18.5 days (n = 20; S.E. = 3.1) and males for 8.25 days (n = 20; S.E. = 1.23). Females produce an average of 23 offspring in a lifetime, while female false codling moths produce about 800 eggs each. A high number of parasitoids will be required per hectare to reduce the population of false codling moth. Captive rearing of A. bishopi proved difficult due to viral and fungal contamination. Agathis bishopi has potential for use in an integrated pest management programme once the hurdle of mass-rearing has been overcome.
- Full Text:
- Date Issued: 2008
Information and communication technology in A-level physics teaching and learning at secondary schools in Manicaland Zimbabwe: multiple case studies
- Authors: Mlambo, Watson
- Date: 2008
- Subjects: Information technology -- Zimbabwe Educational technology -- Zimbabwe Education, Secondary -- Zimbabwe Information technology -- Study and teaching (Secondary) -- Zimbabwe Physics -- Study and teaching (Secondary) -- Zimbabwe Computer-assisted instruction -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1576 , http://hdl.handle.net/10962/d1003458
- Description: As personal computers (PCs) and related ICTs become more and more omnipresent than ever before in institutions of education, teachers are faced with the challenge of having to teach in ICT rich environments. Some syllabuses increase this pressure by stipulating where ICT may be applied. While past research efforts have focused on presence of and/or effectiveness of ICTs on achieving various didactic goals, there is limited literature on the extent to which actual practice occurred naturally. It was the aim of this study to determine the extent to which Physics teachers and students used ICT in their usual teaching/learning ambience, referred to as natural settings in this study. Using activity theory as a theoretical lens, multiple case studies were chosen as a strategy using 10 schools, 15 Physics teachers, 20 A-level Physics students and 10 ICT teachers (computer specialists). Questionnaires, observations and informal and focus group interviews were used to elicit responses from students, teachers and computer specialists. It emerged from the case studies that despite the presence of apt ICT infrastructure in the schools and although the teachers had a positive attitude towards the use of ICT for teaching and learning of Physics, teachers were apathetic when it came to the actual use. Some of the reasons militating against use were lack of an ICT policy, school authority, and monopoly of computers enjoyed by computer studies teachers. However among students there were ‘early starters’ who used ICTs outside of school, a situation that tended to change the Physics learning environment. These findings led to a proposal for a post of Computer Specialist (CS) in the schools. The need for developing ICT policy at all levels namely national, Ministry of Education and the school was also proposed. Lastly staff development in the use ICT for Physics teachers was proposed as indispensable.
- Full Text:
- Date Issued: 2008
- Authors: Mlambo, Watson
- Date: 2008
- Subjects: Information technology -- Zimbabwe Educational technology -- Zimbabwe Education, Secondary -- Zimbabwe Information technology -- Study and teaching (Secondary) -- Zimbabwe Physics -- Study and teaching (Secondary) -- Zimbabwe Computer-assisted instruction -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1576 , http://hdl.handle.net/10962/d1003458
- Description: As personal computers (PCs) and related ICTs become more and more omnipresent than ever before in institutions of education, teachers are faced with the challenge of having to teach in ICT rich environments. Some syllabuses increase this pressure by stipulating where ICT may be applied. While past research efforts have focused on presence of and/or effectiveness of ICTs on achieving various didactic goals, there is limited literature on the extent to which actual practice occurred naturally. It was the aim of this study to determine the extent to which Physics teachers and students used ICT in their usual teaching/learning ambience, referred to as natural settings in this study. Using activity theory as a theoretical lens, multiple case studies were chosen as a strategy using 10 schools, 15 Physics teachers, 20 A-level Physics students and 10 ICT teachers (computer specialists). Questionnaires, observations and informal and focus group interviews were used to elicit responses from students, teachers and computer specialists. It emerged from the case studies that despite the presence of apt ICT infrastructure in the schools and although the teachers had a positive attitude towards the use of ICT for teaching and learning of Physics, teachers were apathetic when it came to the actual use. Some of the reasons militating against use were lack of an ICT policy, school authority, and monopoly of computers enjoyed by computer studies teachers. However among students there were ‘early starters’ who used ICTs outside of school, a situation that tended to change the Physics learning environment. These findings led to a proposal for a post of Computer Specialist (CS) in the schools. The need for developing ICT policy at all levels namely national, Ministry of Education and the school was also proposed. Lastly staff development in the use ICT for Physics teachers was proposed as indispensable.
- Full Text:
- Date Issued: 2008
Application of dermal microdialysis and tape stripping methods to determine the bioavailability and/or bioequivalence of topical ketoprofen formulations
- Tettey-Amlalo, Ralph Nii Okai
- Authors: Tettey-Amlalo, Ralph Nii Okai
- Date: 2008
- Subjects: Drugs -- Therapeutic equivalency Transdermal medication High performance liquid chromatography Nonsteroidal anti-inflammatory agents -- Bioavailability Nonsteroidal anti-inflammatory agents -- Effectiveness Nonsteroidal anti-inflammatory agents -- Testing Nonsteroidal anti-inflammatory agents -- Side effects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3796 , http://hdl.handle.net/10962/d1003274
- Description: The widespread acceptance of topical formulations intended for local and/or regional activity has prompted renewed interest in developing a model to determine the bioavailability of drugs in order to establish bioequivalence as a means of evaluating formulation performance of multisource products and also for use during formulation development. Current in vivo techniques such as blister suction and skin biopsy amongst others used to determine the bioavailability and/or bioequivalence of topical formulations are either too invasive to generate appropriate concentration-time profiles or require large numbers of study subjects thereby making the study expensive and time-consuming. Moreover, there are currently no sampling techniques that can demonstrate dermal bioavailability and/or bioequivalence of topical formulations intended for local and/or regional activity. Dermal microdialysis is a relatively new application of microdialysis that permits continuous monitoring of endogenous and/or exogenous solutes in the interstitial fluid. The technique is involves the implantation of semi-permeable membranes which are perfused with an isotonic medium at extremely slow flow rates and collection of microlitre sample volumes containing diffused drugs. Tape stripping, a relatively older technique, has been extensively used in comparative bioavailability studies of various topical formulations. However, due to shortcomings arising from reproducibility and inter-subject variation amongst others, the published FDA guidance outlining the initial protocol was subsequently withdrawn. The incorporation of transepidermal water loss with tape stripping has garnered renewed interest and has been used for the determination of drug bioavailability from a number of topical formulations. Hence the primary objective of this research is to develop and evaluate microdialysis sampling and tape stripping techniques, including the incorporation of the determination of transepidermal water loss, to assess the dermal bioavailability of ketoprofen from topical gel formulations and to develop models for bioequivalence assessment. A rapid UPLC-MS/MS method with requisite sensitivity for the analysis of samples generated from dermal microdialysis was developed and validated which accommodated the microlitre sample volumes collected. An HPLC-UV method was developed and validated for the analysis of samples generated from the in vitro microdialysis and in vivo tape stripping studies. The work presented herein contributes to a growing body of scientific knowledge seeking to develop a model for the determination of bioequivalence of pharmaceutically equivalent topical formulations intended for local and/or regional activity in human subjects.
- Full Text:
- Date Issued: 2008
- Authors: Tettey-Amlalo, Ralph Nii Okai
- Date: 2008
- Subjects: Drugs -- Therapeutic equivalency Transdermal medication High performance liquid chromatography Nonsteroidal anti-inflammatory agents -- Bioavailability Nonsteroidal anti-inflammatory agents -- Effectiveness Nonsteroidal anti-inflammatory agents -- Testing Nonsteroidal anti-inflammatory agents -- Side effects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3796 , http://hdl.handle.net/10962/d1003274
- Description: The widespread acceptance of topical formulations intended for local and/or regional activity has prompted renewed interest in developing a model to determine the bioavailability of drugs in order to establish bioequivalence as a means of evaluating formulation performance of multisource products and also for use during formulation development. Current in vivo techniques such as blister suction and skin biopsy amongst others used to determine the bioavailability and/or bioequivalence of topical formulations are either too invasive to generate appropriate concentration-time profiles or require large numbers of study subjects thereby making the study expensive and time-consuming. Moreover, there are currently no sampling techniques that can demonstrate dermal bioavailability and/or bioequivalence of topical formulations intended for local and/or regional activity. Dermal microdialysis is a relatively new application of microdialysis that permits continuous monitoring of endogenous and/or exogenous solutes in the interstitial fluid. The technique is involves the implantation of semi-permeable membranes which are perfused with an isotonic medium at extremely slow flow rates and collection of microlitre sample volumes containing diffused drugs. Tape stripping, a relatively older technique, has been extensively used in comparative bioavailability studies of various topical formulations. However, due to shortcomings arising from reproducibility and inter-subject variation amongst others, the published FDA guidance outlining the initial protocol was subsequently withdrawn. The incorporation of transepidermal water loss with tape stripping has garnered renewed interest and has been used for the determination of drug bioavailability from a number of topical formulations. Hence the primary objective of this research is to develop and evaluate microdialysis sampling and tape stripping techniques, including the incorporation of the determination of transepidermal water loss, to assess the dermal bioavailability of ketoprofen from topical gel formulations and to develop models for bioequivalence assessment. A rapid UPLC-MS/MS method with requisite sensitivity for the analysis of samples generated from dermal microdialysis was developed and validated which accommodated the microlitre sample volumes collected. An HPLC-UV method was developed and validated for the analysis of samples generated from the in vitro microdialysis and in vivo tape stripping studies. The work presented herein contributes to a growing body of scientific knowledge seeking to develop a model for the determination of bioequivalence of pharmaceutically equivalent topical formulations intended for local and/or regional activity in human subjects.
- Full Text:
- Date Issued: 2008
An analysis of the implementation of sustainability principles in Buffalo City Municipality
- Authors: Mniki, Phumzile
- Date: 2008
- Subjects: Buffalo City (South Africa) Local government -- South Africa -- Eastern Cape -- Case studies Municipal government -- South Africa -- Eastern Cape -- Case studies Sustainable development -- South Africa -- Eastern Cape -- Case studies Strategic planning -- South Africa -- Eastern Cape -- Case studies Economic development -- South Africa -- Eastern Cape -- Case studies
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:790 , http://hdl.handle.net/10962/d1003941
- Description: This study investigated the planning, implementation and monitoring of sustainability principles in Buffalo City Municipality (BCM), in the Eastern Cape Province. It also analysed how reporting on sustainability principles was done at this municipality. The research was conducted as a qualitative case study that used analyses of documents, questionnaires and interviews to gather data. All respondents were involved with BCM, some as municipal officials in key positions in the different directorates and others as councillors. The study was contextualised within the area of sustainable development at local government level. The focus was on how the mandate of sustainable local development at local government level was met in BCM. The focus was on the planning, implementation and monitoring of stipulations of Local Agenda 21 and sustainability principles. The study focused on the provision of basic services; inter-generational equity; integration of economic, social and environmental aspects; community involvement; institutional capacity building; partnerships, and global links. The study established that Buffalo City Municipality incorporated sustainability in its vision. There was a lack of common understanding of the meaning of sustainability. Sustainability principles featured prominently at the integrated development planning phase but were less explicitly mentioned in the implementation, monitoring and reporting phases. Sustainability principles were subsumed in the developmental goals of the municipality. The study also highlighted the need for a strategy to have an institution-wide implementation of sustainability principles which would incorporate raising awareness about sustainability and its value.
- Full Text:
- Date Issued: 2008
- Authors: Mniki, Phumzile
- Date: 2008
- Subjects: Buffalo City (South Africa) Local government -- South Africa -- Eastern Cape -- Case studies Municipal government -- South Africa -- Eastern Cape -- Case studies Sustainable development -- South Africa -- Eastern Cape -- Case studies Strategic planning -- South Africa -- Eastern Cape -- Case studies Economic development -- South Africa -- Eastern Cape -- Case studies
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:790 , http://hdl.handle.net/10962/d1003941
- Description: This study investigated the planning, implementation and monitoring of sustainability principles in Buffalo City Municipality (BCM), in the Eastern Cape Province. It also analysed how reporting on sustainability principles was done at this municipality. The research was conducted as a qualitative case study that used analyses of documents, questionnaires and interviews to gather data. All respondents were involved with BCM, some as municipal officials in key positions in the different directorates and others as councillors. The study was contextualised within the area of sustainable development at local government level. The focus was on how the mandate of sustainable local development at local government level was met in BCM. The focus was on the planning, implementation and monitoring of stipulations of Local Agenda 21 and sustainability principles. The study focused on the provision of basic services; inter-generational equity; integration of economic, social and environmental aspects; community involvement; institutional capacity building; partnerships, and global links. The study established that Buffalo City Municipality incorporated sustainability in its vision. There was a lack of common understanding of the meaning of sustainability. Sustainability principles featured prominently at the integrated development planning phase but were less explicitly mentioned in the implementation, monitoring and reporting phases. Sustainability principles were subsumed in the developmental goals of the municipality. The study also highlighted the need for a strategy to have an institution-wide implementation of sustainability principles which would incorporate raising awareness about sustainability and its value.
- Full Text:
- Date Issued: 2008
Reflective accounts of childhood inter-species experiences in a Southern-African context: a phenomenological-hermeneutic exploration
- Authors: Rump, Samantha
- Date: 2008
- Subjects: Child psychology -- South Africa Child development -- South Africa Human-animal relationships -- South Africa Children and animals -- South Africa Animal psychology -- South Africa Hermeneutics Phenomenology
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3045 , http://hdl.handle.net/10962/d1002554
- Description: The aims of this research were to describe in rich phenomenological detail the recollected childhood experiences described by three South African adults of growing up with animals in the context of a traditionally African cultural perspective in South Africa; as well as to document the emotional, physical and social effects of inter-species relationships as described by these participants, in order to explore and situate these experiences in relation to broad international perspectives on the contribution of animals to human development. The question of how these described experiences correlate with broad international perspectives on the contribution of animals to human development comprised the hermeneutic of the study. Here it was found that the experiences of these South African individuals were generally in keeping with the trends found in the literature. Participants attributed to their childhood relationships with animals a variety of benefits. These benefits occur on a range of levels, from the physical to the cognitive, and the psychosocial. The emotional attachment of the participants to animals with whom they had interacted in childhood correlated with the nature of interspecies relationships as anticipated by the literature. Cultural differences in the conceptualisation of inter-species relationships, between western and traditionally African ideologies, appeared to influence the moral and ethical positions assumed by the participants, while the subjective nature of the described attachment between participants and animals remains qualitatively similar across cultures, when explored in relation to international research. The similarities between the experiences of the participants and international research findings lend credence to Wilson’s hypothesis that all human beings are potentially able to connect in deep and profound ways with their natural environment, and that this connection contributes to the development of social and cognitive skills, as well as constituting emotional support and stability. The research concludes with an examination of its own limitations and suggestions are made for further research.
- Full Text:
- Date Issued: 2008
- Authors: Rump, Samantha
- Date: 2008
- Subjects: Child psychology -- South Africa Child development -- South Africa Human-animal relationships -- South Africa Children and animals -- South Africa Animal psychology -- South Africa Hermeneutics Phenomenology
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3045 , http://hdl.handle.net/10962/d1002554
- Description: The aims of this research were to describe in rich phenomenological detail the recollected childhood experiences described by three South African adults of growing up with animals in the context of a traditionally African cultural perspective in South Africa; as well as to document the emotional, physical and social effects of inter-species relationships as described by these participants, in order to explore and situate these experiences in relation to broad international perspectives on the contribution of animals to human development. The question of how these described experiences correlate with broad international perspectives on the contribution of animals to human development comprised the hermeneutic of the study. Here it was found that the experiences of these South African individuals were generally in keeping with the trends found in the literature. Participants attributed to their childhood relationships with animals a variety of benefits. These benefits occur on a range of levels, from the physical to the cognitive, and the psychosocial. The emotional attachment of the participants to animals with whom they had interacted in childhood correlated with the nature of interspecies relationships as anticipated by the literature. Cultural differences in the conceptualisation of inter-species relationships, between western and traditionally African ideologies, appeared to influence the moral and ethical positions assumed by the participants, while the subjective nature of the described attachment between participants and animals remains qualitatively similar across cultures, when explored in relation to international research. The similarities between the experiences of the participants and international research findings lend credence to Wilson’s hypothesis that all human beings are potentially able to connect in deep and profound ways with their natural environment, and that this connection contributes to the development of social and cognitive skills, as well as constituting emotional support and stability. The research concludes with an examination of its own limitations and suggestions are made for further research.
- Full Text:
- Date Issued: 2008
The impact of the identification process and the corporate social responsibility process on the effectiveness of multi-racial advertising in South Africa
- Authors: Johnson, Guillaume Desire
- Date: 2008
- Subjects: Marketing -- South Africa Advertising -- South Africa Sales promotion -- South Africa Consumers' preferences -- South Africa Marketing research -- South Africa Consumer behavior -- South Africa Consumption (Economics) -- Social aspect Attribution (Social psychology) South Africans -- Race identity Race awareness -- South Africa Ethnopsychology -- South Africa Group identity Racially mixed people
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1196 , http://hdl.handle.net/10962/d1008263
- Description: Selecting actors to appear in an advertisement is an important decision which has a crucial impact on the effectiveness of an advertising campaign. The same message, delivered by different actors, produces varying outcomes among consumers. This dilemma concerning the choice of actors occurs particularly in multi-racial societies, such as South Africa, where advertisers have to target different sectors of the community. In multi-racial societies, the choice of actors in advertisements goes beyond the usual commercial reasons. Indeed, two dimensions are generally conferred to multi-racial advertising. Firstly, the use of multi-racial representations allows for the targeting of a wider population that also owns a wider purchasing power. Marketers who want to market their brand use, for example, white and black actors so that white and black consumers can identify with the actors and recognize themselves as the target of the advertisement. Secondly, the multi-racial representations of this type of advertising hold a social role that counteracts the segregated depiction of the society. Consumers who are exposed to a multi-racial advertisement might perceive this social dimension and attribute a social responsibility to the advertisement. The purpose of this thesis is to examine the influence of the above dimensions on the effectiveness of a multi-racial advertisement. On the one hand, this study investigates the Identification Process followed by a consumer exposed to a multi-racial advertisement. On the other hand, it examines how consumers attribute a social responsibility to a specific multiracial advertisement and how this attribution, in turn, influences their responses to the advertisement and brand. Finally, the impacts of both of these dimensions on consumer behaviour are compared and the most persuasive dimension is identified. This thesis draws on Attribution Theory and Identification Theory in arguing that there are strong economic imperatives for adopting a multi-racial advertising approach. The thesis develops a conceptual framework and tests empirically hypotheses regarding the key constructs and moderating variables. The empirical results point out that both dimensions symbiotically influence the effectiveness of a multi-racial advertisement. Specifically, the results highlight that the social responsibility attributed by the viewers to the advertisement influences their behaviour more than the Identification Process.
- Full Text:
- Date Issued: 2008
- Authors: Johnson, Guillaume Desire
- Date: 2008
- Subjects: Marketing -- South Africa Advertising -- South Africa Sales promotion -- South Africa Consumers' preferences -- South Africa Marketing research -- South Africa Consumer behavior -- South Africa Consumption (Economics) -- Social aspect Attribution (Social psychology) South Africans -- Race identity Race awareness -- South Africa Ethnopsychology -- South Africa Group identity Racially mixed people
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1196 , http://hdl.handle.net/10962/d1008263
- Description: Selecting actors to appear in an advertisement is an important decision which has a crucial impact on the effectiveness of an advertising campaign. The same message, delivered by different actors, produces varying outcomes among consumers. This dilemma concerning the choice of actors occurs particularly in multi-racial societies, such as South Africa, where advertisers have to target different sectors of the community. In multi-racial societies, the choice of actors in advertisements goes beyond the usual commercial reasons. Indeed, two dimensions are generally conferred to multi-racial advertising. Firstly, the use of multi-racial representations allows for the targeting of a wider population that also owns a wider purchasing power. Marketers who want to market their brand use, for example, white and black actors so that white and black consumers can identify with the actors and recognize themselves as the target of the advertisement. Secondly, the multi-racial representations of this type of advertising hold a social role that counteracts the segregated depiction of the society. Consumers who are exposed to a multi-racial advertisement might perceive this social dimension and attribute a social responsibility to the advertisement. The purpose of this thesis is to examine the influence of the above dimensions on the effectiveness of a multi-racial advertisement. On the one hand, this study investigates the Identification Process followed by a consumer exposed to a multi-racial advertisement. On the other hand, it examines how consumers attribute a social responsibility to a specific multiracial advertisement and how this attribution, in turn, influences their responses to the advertisement and brand. Finally, the impacts of both of these dimensions on consumer behaviour are compared and the most persuasive dimension is identified. This thesis draws on Attribution Theory and Identification Theory in arguing that there are strong economic imperatives for adopting a multi-racial advertising approach. The thesis develops a conceptual framework and tests empirically hypotheses regarding the key constructs and moderating variables. The empirical results point out that both dimensions symbiotically influence the effectiveness of a multi-racial advertisement. Specifically, the results highlight that the social responsibility attributed by the viewers to the advertisement influences their behaviour more than the Identification Process.
- Full Text:
- Date Issued: 2008
Ecological role of free-living bacteria in the microbial food web of the temporarily open/closed East Kleinemonde Estuary, South Africa
- Authors: Allan, Elizabeth Louise
- Date: 2008
- Subjects: Bacterial growth -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Microbial ecology -- South Africa -- Eastern Cape , Nutrient cycles -- South Africa -- Eastern Cape , Food chains (Ecology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5666 , http://hdl.handle.net/10962/d1005351 , Bacterial growth -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Microbial ecology -- South Africa -- Eastern Cape , Nutrient cycles -- South Africa -- Eastern Cape , Food chains (Ecology)
- Description: The main aim of this study was to assess the “top-down” and “bottom-up” control of bacterial production in the small temporarily open/closed East Kleinemonde Estuary, situated on the south-eastern coastline of southern Africa. Spatial and temporal patterns in bacterial abundance, biomass and production and the importance of abiotic and biotic factors were investigated over the period May 2006 to April 2007. The trophic interactions between bacteria, phytoplankton, nanoflagellates (< 20 μm), microzooplankton (< 200 μm) and mesozooplankton (< 2 000 μm) were investigated during winter and summer. Bacterial abundance, biomass and production ranged between 1.00 × 10⁹ and 4.93 × 10⁹ cells 1⁻¹, 32.4 and 109 μg C 1⁻¹ and 0.01 and 1.99 μg C 1⁻¹ h⁻¹, respectively. With a few exceptions there were no spatial patterns in the values. Bacterial abundance, biomass and production, however, demonstrated a distinct temporal pattern with the lowest values consistently recorded during the winter months. Nanoflagellate and bacterial abundances were significantly correlated to one another (lower reaches: r = 0.818, p < 0.001; middle reaches: r = 0.628, p < 0.001; upper reaches: r = 0.484, p < 0.05) suggesting a strong predator-prey relationship. The frequency of visibly infected bacterial cells and the mean number of virus particles within each bacterial cell during this study demonstrated no temporal or spatial patterns and ranged from 0.5 to 6.1 % and 12.0 to 37.5 virus particles per bacterium, respectively. Viral infection and lysis was thus a constant source of bacterial mortality throughout the year. The estimated percentage of bacterial production removed by viral lysis ranged between 7.8 and 88.9% of the total which suggests that viral lysis represented a very important source of bacterial mortality during this study. The biological interactions between the selected components of the plankton community demonstrated that among the heterotrophic components of the plankton, the nanoflagellates were identified as the most important consumers of bacteria and small phytoplankton cells (< 20 μm). In the presence of microzooplankton the impact of the nanoflagellates on both the bacteria and phytoplankton was reduced, indicating that larger heterotrophs were preying upon the nanoflagellates. Mesozooplankton, however, appeared to exert the greatest impact on nanoflagellates. In the cascading experiments, the data suggest that mesozooplankton consume nanoflagellates, which resulted in a decrease in the predation impact of these organisms on the bacteria. This result is consistent with predator-prey cascades. The presence of the larger heterotrophs therefore, mediates the interactions between the primary bacterivores, the nanoflagellates, and the bacteria within the temporarily open/closed East Kleinemonde Estuary.
- Full Text:
- Date Issued: 2008
- Authors: Allan, Elizabeth Louise
- Date: 2008
- Subjects: Bacterial growth -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Microbial ecology -- South Africa -- Eastern Cape , Nutrient cycles -- South Africa -- Eastern Cape , Food chains (Ecology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5666 , http://hdl.handle.net/10962/d1005351 , Bacterial growth -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Microbial ecology -- South Africa -- Eastern Cape , Nutrient cycles -- South Africa -- Eastern Cape , Food chains (Ecology)
- Description: The main aim of this study was to assess the “top-down” and “bottom-up” control of bacterial production in the small temporarily open/closed East Kleinemonde Estuary, situated on the south-eastern coastline of southern Africa. Spatial and temporal patterns in bacterial abundance, biomass and production and the importance of abiotic and biotic factors were investigated over the period May 2006 to April 2007. The trophic interactions between bacteria, phytoplankton, nanoflagellates (< 20 μm), microzooplankton (< 200 μm) and mesozooplankton (< 2 000 μm) were investigated during winter and summer. Bacterial abundance, biomass and production ranged between 1.00 × 10⁹ and 4.93 × 10⁹ cells 1⁻¹, 32.4 and 109 μg C 1⁻¹ and 0.01 and 1.99 μg C 1⁻¹ h⁻¹, respectively. With a few exceptions there were no spatial patterns in the values. Bacterial abundance, biomass and production, however, demonstrated a distinct temporal pattern with the lowest values consistently recorded during the winter months. Nanoflagellate and bacterial abundances were significantly correlated to one another (lower reaches: r = 0.818, p < 0.001; middle reaches: r = 0.628, p < 0.001; upper reaches: r = 0.484, p < 0.05) suggesting a strong predator-prey relationship. The frequency of visibly infected bacterial cells and the mean number of virus particles within each bacterial cell during this study demonstrated no temporal or spatial patterns and ranged from 0.5 to 6.1 % and 12.0 to 37.5 virus particles per bacterium, respectively. Viral infection and lysis was thus a constant source of bacterial mortality throughout the year. The estimated percentage of bacterial production removed by viral lysis ranged between 7.8 and 88.9% of the total which suggests that viral lysis represented a very important source of bacterial mortality during this study. The biological interactions between the selected components of the plankton community demonstrated that among the heterotrophic components of the plankton, the nanoflagellates were identified as the most important consumers of bacteria and small phytoplankton cells (< 20 μm). In the presence of microzooplankton the impact of the nanoflagellates on both the bacteria and phytoplankton was reduced, indicating that larger heterotrophs were preying upon the nanoflagellates. Mesozooplankton, however, appeared to exert the greatest impact on nanoflagellates. In the cascading experiments, the data suggest that mesozooplankton consume nanoflagellates, which resulted in a decrease in the predation impact of these organisms on the bacteria. This result is consistent with predator-prey cascades. The presence of the larger heterotrophs therefore, mediates the interactions between the primary bacterivores, the nanoflagellates, and the bacteria within the temporarily open/closed East Kleinemonde Estuary.
- Full Text:
- Date Issued: 2008
Radio Frequency Identification (RFID) adoption in the South African retail sector: an investigation of perceptions held by members of the retail sector regarding the adoption constraints
- Authors: Liu, Haidi
- Date: 2008
- Subjects: Radio frequency identification systems , Retail trade -- South Africa , Business logistics -- Management -- South Africa , Retail trade -- Employees -- South Africa , Retail trade -- Technological innovations , Radio waves , Consumer profiling
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:1144 , http://hdl.handle.net/10962/d1002774 , Radio frequency identification systems , Retail trade -- South Africa , Business logistics -- Management -- South Africa , Retail trade -- Employees -- South Africa , Retail trade -- Technological innovations , Radio waves , Consumer profiling
- Description: Radio Frequency Identification (RFID) technology is a ethod of identifying unique items using radio waves that communicate between RFID tags and readers without line-of-sight readability. RFID technology provides great potential in many industries and a wide spectrum of possible uses. Areas of application include person identification, logistics, pharmaceutical, access control, security guard monitoring and asset management. One of the areas where RFID is being used and where it promises excellent results is the retail industry. While RFID systems have the potential to revolutionise the way products and goods are tracked and traced in the retail supply chain, barriers to its widespread adoption exist: for example; technical constraints, return on investment constraints, a lack of awareness and education and as well as privacy and security issues. The research aims to identify the barriers to the adoption of RFID and to investigate the perceptions of RFID held by members of the retail sector in South Africa (SA). Current research and available literature are used to identify RFID adoption barriers and a conceptual framework on this subject is proposed, which is then verified by SA retailers’ perceptions, established by means of a survey. Initial barriers to widespread adoption include a shortage in skills, a lack of standards, high costs associated with RFID devices, the difficulty of integrating with current legacy systems, and a lack of familiarity with the system. Finally, an enhanced framework is proposed, describing RFID adoption barriers within the South African retail sector. In summary, the framework is an outline of the barriers impacting RFID adoption in the SA retail sector that need to be considered and addressed. The framework identifies six categories of RFID adoption barriers, with each category containing two or more barriers relating to that particular category. These categories are Technological, Cost and return on investment, Privacy and security, Implementation, Organisational factors and People.
- Full Text:
- Date Issued: 2008
- Authors: Liu, Haidi
- Date: 2008
- Subjects: Radio frequency identification systems , Retail trade -- South Africa , Business logistics -- Management -- South Africa , Retail trade -- Employees -- South Africa , Retail trade -- Technological innovations , Radio waves , Consumer profiling
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:1144 , http://hdl.handle.net/10962/d1002774 , Radio frequency identification systems , Retail trade -- South Africa , Business logistics -- Management -- South Africa , Retail trade -- Employees -- South Africa , Retail trade -- Technological innovations , Radio waves , Consumer profiling
- Description: Radio Frequency Identification (RFID) technology is a ethod of identifying unique items using radio waves that communicate between RFID tags and readers without line-of-sight readability. RFID technology provides great potential in many industries and a wide spectrum of possible uses. Areas of application include person identification, logistics, pharmaceutical, access control, security guard monitoring and asset management. One of the areas where RFID is being used and where it promises excellent results is the retail industry. While RFID systems have the potential to revolutionise the way products and goods are tracked and traced in the retail supply chain, barriers to its widespread adoption exist: for example; technical constraints, return on investment constraints, a lack of awareness and education and as well as privacy and security issues. The research aims to identify the barriers to the adoption of RFID and to investigate the perceptions of RFID held by members of the retail sector in South Africa (SA). Current research and available literature are used to identify RFID adoption barriers and a conceptual framework on this subject is proposed, which is then verified by SA retailers’ perceptions, established by means of a survey. Initial barriers to widespread adoption include a shortage in skills, a lack of standards, high costs associated with RFID devices, the difficulty of integrating with current legacy systems, and a lack of familiarity with the system. Finally, an enhanced framework is proposed, describing RFID adoption barriers within the South African retail sector. In summary, the framework is an outline of the barriers impacting RFID adoption in the SA retail sector that need to be considered and addressed. The framework identifies six categories of RFID adoption barriers, with each category containing two or more barriers relating to that particular category. These categories are Technological, Cost and return on investment, Privacy and security, Implementation, Organisational factors and People.
- Full Text:
- Date Issued: 2008
Melanie Klein: a psychobiographical study
- Authors: Espinosa, Marianna J
- Date: 2008
- Subjects: Klein, Melanie Psychology -- Biographical methods Psychoanalysis
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2971 , http://hdl.handle.net/10962/d1002480
- Description: The objective of psychobiography is a better understanding of individuals, and psychobiographical case studies add meaning and value to research (Runyan, 1988a). Melanie Klein was chosen for this study through a purposive sampling method due to her contributions to the discipline of psychology, which placed her in a distinguished position regarding twentieth century psychoanalysis. Furthermore, no other psychobiography has been written on Klein. The primary aim of this study was to present the reader with a basic description of her life, and a secondary aim was to accomplish an in-depth description of Klein within her social and historical context. Due to these aims and the nature of psychobiography, it may be said that this is a qualitative study based on a single case method, described as explorative and descriptive. Data was analysed according to Huberman and Miles’ (1994) approach which consists of data reduction, display and verification. This study was guided by Levinson’s (1996) theory of Adult Development in Women. The theory allowed for an in-depth description of Klein’s experiences and social and historical contexts by merely illuminating her life. Finally, it may be said that this study contributed to the limited amount of psychobiographical research in South Africa.
- Full Text:
- Date Issued: 2008
- Authors: Espinosa, Marianna J
- Date: 2008
- Subjects: Klein, Melanie Psychology -- Biographical methods Psychoanalysis
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2971 , http://hdl.handle.net/10962/d1002480
- Description: The objective of psychobiography is a better understanding of individuals, and psychobiographical case studies add meaning and value to research (Runyan, 1988a). Melanie Klein was chosen for this study through a purposive sampling method due to her contributions to the discipline of psychology, which placed her in a distinguished position regarding twentieth century psychoanalysis. Furthermore, no other psychobiography has been written on Klein. The primary aim of this study was to present the reader with a basic description of her life, and a secondary aim was to accomplish an in-depth description of Klein within her social and historical context. Due to these aims and the nature of psychobiography, it may be said that this is a qualitative study based on a single case method, described as explorative and descriptive. Data was analysed according to Huberman and Miles’ (1994) approach which consists of data reduction, display and verification. This study was guided by Levinson’s (1996) theory of Adult Development in Women. The theory allowed for an in-depth description of Klein’s experiences and social and historical contexts by merely illuminating her life. Finally, it may be said that this study contributed to the limited amount of psychobiographical research in South Africa.
- Full Text:
- Date Issued: 2008
Photosynthetic and growth response of C₃ and C₄ subspecies of Alloteropsis semialata to nitrogen-supply
- Authors: Abraham, Trevor Ian
- Date: 2008
- Subjects: Photosynthesis , Plants -- Effect of nitrogen on , Growth (Plants) , Plant ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4182 , http://hdl.handle.net/10962/d1003750 , Photosynthesis , Plants -- Effect of nitrogen on , Growth (Plants) , Plant ecology
- Description: The greater photosynthetic nitrogen use efficiency (PNUE) of C4 compared with C3 plants may explain the relative success of C4 grasses in nutrient poor environments. This study compared the responses in photosynthetic parameters, leaf nitrogen and biomass allocation between the C3 and C4 subspecies of Alloteropsis semialata supplied soil nitrogen at three levels. Photosynthesis was assessed by means of CO2 response curves and the leaf nitrogen content assayed. Plants were destructively harvested, leaf areas determined and the dry biomass of functional plant components was measured. Results confirmed that the higher PNUE of C4 plants allowed them to accumulate more biomass than C3 plants at the high nitrogen level, despite smaller leaf areas. The greater productivity of C4 plants enabled them to invest more in storage and sexual reproduction than in leaves when compared to the C3 plants. In contrast the C3 plants invested biomass in less efficient and more nitrogen demanding leaves and bigger root systems. PNUE and photosynthetic rates were not significantly affected by nitrogen-limitation in either subspecies and the major response was a decrease in biomass accumulation and an increase in biomass allocation to roots. This altered root to shoot ratio was accompanied by a lowered allocation to sexual reproduction in the C4 subspecies, but an unaltered allocation to leaves, while in the C3 subspecies there was a decrease in leaf allocation. In a further experiment, the C4 subspecies was supplied three levels of nitrogen provided as nitrate, or alternatively as ammonium plus nitrate, and leaves were excised to within 5 cm of the ground at the start of treatment. Prior to flowering, photosynthesis was assessed by means of CO2 response curves and the plants were destructively harvested. Leaf areas and the dry biomass of functional plant components were determined, and at levels of nitrogen supply higher than those found in savanna soils the rate of photosynthesis was increased. Leaf re-growth was reduced by severe nitrogen limitation and co-provision of nitrate and ammonium had no significant effect other than increased tillering. Both subspecies of Alloteropsis semialata are adapted to nutrient poor environments and maintain photosynthetic rates by reducing leaf area. The C4 subspecies is likely to show greater resilience in disturbance-prone environments by exploiting its higher PNUE to allocate greater resources to storage and sexual reproduction, while the C3 subspecies is usually found in environments with closed canopies which favour vegetative growth, and allocate greater resources to leaves and roots.
- Full Text:
- Date Issued: 2008
- Authors: Abraham, Trevor Ian
- Date: 2008
- Subjects: Photosynthesis , Plants -- Effect of nitrogen on , Growth (Plants) , Plant ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4182 , http://hdl.handle.net/10962/d1003750 , Photosynthesis , Plants -- Effect of nitrogen on , Growth (Plants) , Plant ecology
- Description: The greater photosynthetic nitrogen use efficiency (PNUE) of C4 compared with C3 plants may explain the relative success of C4 grasses in nutrient poor environments. This study compared the responses in photosynthetic parameters, leaf nitrogen and biomass allocation between the C3 and C4 subspecies of Alloteropsis semialata supplied soil nitrogen at three levels. Photosynthesis was assessed by means of CO2 response curves and the leaf nitrogen content assayed. Plants were destructively harvested, leaf areas determined and the dry biomass of functional plant components was measured. Results confirmed that the higher PNUE of C4 plants allowed them to accumulate more biomass than C3 plants at the high nitrogen level, despite smaller leaf areas. The greater productivity of C4 plants enabled them to invest more in storage and sexual reproduction than in leaves when compared to the C3 plants. In contrast the C3 plants invested biomass in less efficient and more nitrogen demanding leaves and bigger root systems. PNUE and photosynthetic rates were not significantly affected by nitrogen-limitation in either subspecies and the major response was a decrease in biomass accumulation and an increase in biomass allocation to roots. This altered root to shoot ratio was accompanied by a lowered allocation to sexual reproduction in the C4 subspecies, but an unaltered allocation to leaves, while in the C3 subspecies there was a decrease in leaf allocation. In a further experiment, the C4 subspecies was supplied three levels of nitrogen provided as nitrate, or alternatively as ammonium plus nitrate, and leaves were excised to within 5 cm of the ground at the start of treatment. Prior to flowering, photosynthesis was assessed by means of CO2 response curves and the plants were destructively harvested. Leaf areas and the dry biomass of functional plant components were determined, and at levels of nitrogen supply higher than those found in savanna soils the rate of photosynthesis was increased. Leaf re-growth was reduced by severe nitrogen limitation and co-provision of nitrate and ammonium had no significant effect other than increased tillering. Both subspecies of Alloteropsis semialata are adapted to nutrient poor environments and maintain photosynthetic rates by reducing leaf area. The C4 subspecies is likely to show greater resilience in disturbance-prone environments by exploiting its higher PNUE to allocate greater resources to storage and sexual reproduction, while the C3 subspecies is usually found in environments with closed canopies which favour vegetative growth, and allocate greater resources to leaves and roots.
- Full Text:
- Date Issued: 2008
Assembly of Omegatetravirus virus-like particles in the yeast Saccharomyces cerevisiae
- Authors: Tomasicchio, Michele
- Date: 2008
- Subjects: Helicoverpa armigera Imbrasia cytherea Viruses RNA viruses Insects -- Viruses Lepidoptera -- Viruses Saccharomyces cerevisiae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3930 , http://hdl.handle.net/10962/d1003989
- Description: The Tetraviridae are a family of ss (+) RNA viruses that specifically infect lepidopteran insects. Their icosahedral capsids are non-enveloped and approximately 40 nm in diameter with T=4 quasi-equivalent symmetry. The omegatetraviruses, which are structurally the best characterised in the family, include Helicoverpa armigera stunt virus (HaSV) and Nudaurelia capensis omega virus (NwV). The omegatetravirus procapsid is composed of 240 identical copies of the capsid precursor proteins, which undergo autoproteolytic cleavage at its carboxyl-terminus generating the mature capsid protein (b) and γ-peptide. This process occurs in vitro following a shift from pH 7.6 to pH 6.0. The viral capsid encapsidates two ss genomic RNAs: The larger RNA1 encodes the viral replicase as well as three small ORFs while RNA2 encodes the capsid precursor protein together with an overlapping ORF designated P17. While a wealth of structural data pertaining to the assembly and maturation of omegatetraviruses is available, little is known about how this relates to their lifecycle. The principle aim of the research described in this thesis was to use an experimental system developed in the yeast, Saccharomyces cerevisiae, to investigate the assembly of HaSV and NwV virus-like particles (VLPs) in terms of maturation and encapsidation of viral RNAs, in vivo. The yeast expression system used two promoter systems for expression of capsid precursor protein: in the first, a hybrid promoter (PGADH) was used for high-level expression, while the second, PGAL1, produced substantially lower levels of the virus capsid protein precursors. An increase in the level of HaSV capsid protein precursor (p71) via the PGADH promoter resulted in a dramatic increase in VLP assembly as compared with the PGAL system. A protein equivalent to the mature capsid protein (p64) appeared at later time intervals following induction of transcription. Transmission electron microscopic studies showed that p64 correlated with the presence of mature VLPs as opposed to procapsids in cells containing p71. This confirmed that the presence of p64 denoted maturation of VLPs in vivo. Further investigation indicated that maturation correlated with cell aging and the onset of apoptosis. It was shown that induction of apoptosis resulted in VLP maturation while inhibition of apoptosis prevented maturation. These results suggested that the process of apoptosis might be the trigger for maturation of virus procapsids in their host cells. The increase in the efficiency of VLP assembly observed in the high-level expression system was proposed to be due to an increase in the cellular concentrations of viral RNA. To test this hypothesis, HaSV P71 was co-expressed with either P71 mRNA or full length RNA2. An increase in the solubility of p71 was observed in cells expressing increased levels of both RNAs, but there was no increase in the efficiency of VLP assembly. Northern analysis of encapsidated RNAs revealed that there was no selective encapsidation of either P71 mRNA or viral RNA2. This data indicated that the increase in viral RNA was not the reason for increased efficiency of VLP assembly, but most likely resulted from higher concentrations of p71 itself. It was decided to determine whether a highly efficient nodavirus replication system developed in yeast for heterologous production of proteins, could be used as a method for expressing the capsid protein precursor. The aim of using this system was to determine if VLPs assembled in a replication system specifically encapsidated viral RNA. Transcripts encoding the NwV capsid protein precursor (p70) were generated in yeast cells by replication of a hybrid RNA template by the Nodamura virus (NoV) replicase. Western analysis confirmed the presence of p70 as well as a protein of 62 kDa corresponding to the mature NwV capsid protein. Northern analysis of purified VLPs showed that NoV RNA1 and RNA3 were encapsidated, but no RNA2 was detected. Taken together, the data lead to the conclusion that specific encapsidation of tetraviral RNAs required more than close proximity of the viral RNAs and assembling virus-like particles. Encapsidation specificity in the omegatetraviruses may require additional viral proteins such as p17 during encapsidation or specific viral RNA encapsidation was replication-dependent. Replication-dependent assembly has been shown in the nodaviruses.
- Full Text:
- Date Issued: 2008
- Authors: Tomasicchio, Michele
- Date: 2008
- Subjects: Helicoverpa armigera Imbrasia cytherea Viruses RNA viruses Insects -- Viruses Lepidoptera -- Viruses Saccharomyces cerevisiae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3930 , http://hdl.handle.net/10962/d1003989
- Description: The Tetraviridae are a family of ss (+) RNA viruses that specifically infect lepidopteran insects. Their icosahedral capsids are non-enveloped and approximately 40 nm in diameter with T=4 quasi-equivalent symmetry. The omegatetraviruses, which are structurally the best characterised in the family, include Helicoverpa armigera stunt virus (HaSV) and Nudaurelia capensis omega virus (NwV). The omegatetravirus procapsid is composed of 240 identical copies of the capsid precursor proteins, which undergo autoproteolytic cleavage at its carboxyl-terminus generating the mature capsid protein (b) and γ-peptide. This process occurs in vitro following a shift from pH 7.6 to pH 6.0. The viral capsid encapsidates two ss genomic RNAs: The larger RNA1 encodes the viral replicase as well as three small ORFs while RNA2 encodes the capsid precursor protein together with an overlapping ORF designated P17. While a wealth of structural data pertaining to the assembly and maturation of omegatetraviruses is available, little is known about how this relates to their lifecycle. The principle aim of the research described in this thesis was to use an experimental system developed in the yeast, Saccharomyces cerevisiae, to investigate the assembly of HaSV and NwV virus-like particles (VLPs) in terms of maturation and encapsidation of viral RNAs, in vivo. The yeast expression system used two promoter systems for expression of capsid precursor protein: in the first, a hybrid promoter (PGADH) was used for high-level expression, while the second, PGAL1, produced substantially lower levels of the virus capsid protein precursors. An increase in the level of HaSV capsid protein precursor (p71) via the PGADH promoter resulted in a dramatic increase in VLP assembly as compared with the PGAL system. A protein equivalent to the mature capsid protein (p64) appeared at later time intervals following induction of transcription. Transmission electron microscopic studies showed that p64 correlated with the presence of mature VLPs as opposed to procapsids in cells containing p71. This confirmed that the presence of p64 denoted maturation of VLPs in vivo. Further investigation indicated that maturation correlated with cell aging and the onset of apoptosis. It was shown that induction of apoptosis resulted in VLP maturation while inhibition of apoptosis prevented maturation. These results suggested that the process of apoptosis might be the trigger for maturation of virus procapsids in their host cells. The increase in the efficiency of VLP assembly observed in the high-level expression system was proposed to be due to an increase in the cellular concentrations of viral RNA. To test this hypothesis, HaSV P71 was co-expressed with either P71 mRNA or full length RNA2. An increase in the solubility of p71 was observed in cells expressing increased levels of both RNAs, but there was no increase in the efficiency of VLP assembly. Northern analysis of encapsidated RNAs revealed that there was no selective encapsidation of either P71 mRNA or viral RNA2. This data indicated that the increase in viral RNA was not the reason for increased efficiency of VLP assembly, but most likely resulted from higher concentrations of p71 itself. It was decided to determine whether a highly efficient nodavirus replication system developed in yeast for heterologous production of proteins, could be used as a method for expressing the capsid protein precursor. The aim of using this system was to determine if VLPs assembled in a replication system specifically encapsidated viral RNA. Transcripts encoding the NwV capsid protein precursor (p70) were generated in yeast cells by replication of a hybrid RNA template by the Nodamura virus (NoV) replicase. Western analysis confirmed the presence of p70 as well as a protein of 62 kDa corresponding to the mature NwV capsid protein. Northern analysis of purified VLPs showed that NoV RNA1 and RNA3 were encapsidated, but no RNA2 was detected. Taken together, the data lead to the conclusion that specific encapsidation of tetraviral RNAs required more than close proximity of the viral RNAs and assembling virus-like particles. Encapsidation specificity in the omegatetraviruses may require additional viral proteins such as p17 during encapsidation or specific viral RNA encapsidation was replication-dependent. Replication-dependent assembly has been shown in the nodaviruses.
- Full Text:
- Date Issued: 2008
An investigation of student leadership in an independent school in the Eastern Cape: ʺdo alternative forms of leadership (such as servant leadership) emerge through community building?ʺ
- Authors: Knott-Craig, Ian Duncan
- Date: 2008
- Subjects: Kingswood College Private schools -- South Africa -- Eastern Cape Servant leadership -- South Africa -- Eastern Cape Educational leadership -- South Africa -- Eastern Cape Community and school -- South Africa -- Eastern Cape Student volunteers in social service -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1643 , http://hdl.handle.net/10962/d1003525
- Description: Significant changes have taken place in recent years in leadership theory and practice world wide. Theorizations of effective leadership have evolved from being authoritarian and task-centered to a model in which leaders are encouraged to look beyond their self-interest and prioritize the interests of the group. This study investigates the development of an alternative form of leadership through community building in two male school boarding houses. It attempts to ascertain whether students are able to work collaboratively towards developing an environment conducive to servant leadership. Structured according to the transformative research paradigm, this action research study was conducted in an independent school, Kingswood College, in Grahamstown, South Africa. The College is a traditional independent co-educational school that prides itself on producing leaders. As the school was in the process of reviewing its leadership system, it became an appropriate site to investigate the development of community and to explore possibilities for the emergence of an alternative form of leadership that would reflect the attributes of servant leadership. The participants in the study were volunteers from two boarding houses, who agreed to reflect on their perceptions and experiences of the way in which their houses functioned. My research findings show that through their willingness to engage in moral dialogue, students can transform their boarding houses into closely-knit communities bound together by shared values and beliefs. Closer relationships make for better understanding. As the leaders take on the responsibility of caring for their juniors, a moral obligation begins to manifest itself. Leaders will display the attributes of servant leadership if they are prepared to acknowledge in practice this moral obligation to serve others.
- Full Text:
- Date Issued: 2008
- Authors: Knott-Craig, Ian Duncan
- Date: 2008
- Subjects: Kingswood College Private schools -- South Africa -- Eastern Cape Servant leadership -- South Africa -- Eastern Cape Educational leadership -- South Africa -- Eastern Cape Community and school -- South Africa -- Eastern Cape Student volunteers in social service -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1643 , http://hdl.handle.net/10962/d1003525
- Description: Significant changes have taken place in recent years in leadership theory and practice world wide. Theorizations of effective leadership have evolved from being authoritarian and task-centered to a model in which leaders are encouraged to look beyond their self-interest and prioritize the interests of the group. This study investigates the development of an alternative form of leadership through community building in two male school boarding houses. It attempts to ascertain whether students are able to work collaboratively towards developing an environment conducive to servant leadership. Structured according to the transformative research paradigm, this action research study was conducted in an independent school, Kingswood College, in Grahamstown, South Africa. The College is a traditional independent co-educational school that prides itself on producing leaders. As the school was in the process of reviewing its leadership system, it became an appropriate site to investigate the development of community and to explore possibilities for the emergence of an alternative form of leadership that would reflect the attributes of servant leadership. The participants in the study were volunteers from two boarding houses, who agreed to reflect on their perceptions and experiences of the way in which their houses functioned. My research findings show that through their willingness to engage in moral dialogue, students can transform their boarding houses into closely-knit communities bound together by shared values and beliefs. Closer relationships make for better understanding. As the leaders take on the responsibility of caring for their juniors, a moral obligation begins to manifest itself. Leaders will display the attributes of servant leadership if they are prepared to acknowledge in practice this moral obligation to serve others.
- Full Text:
- Date Issued: 2008
A preliminary investigation into the use of biomarkers and a fish community index to assess estuarine health in selected Eastern Cape estuaries
- Authors: Richardson, Naomi
- Date: 2008
- Subjects: Fish communities -- South Africa -- Eastern Cape Estuarine fishes -- South Africa -- Eastern Cape Estuarine health -- South Africa -- Eastern Cape Estuaries -- South Africa -- Eastern Cape -- Management Coastal zone management -- South Africa -- Eastern Cape Environmental monitoring -- South Africa -- Eastern Cape Estuarine ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5348 , http://hdl.handle.net/10962/d1007480
- Description: The aims of this study were to determine the potential use of biomarkers at multiple levels of biological organisation together with a fish community bioindicator to assess the estuarine health status of three temporarily open/closed estuaries. The estuaries investigated were the East Kleinemonde (EK), Old Woman's (OW) and Mtana (MTN), all of which are situated in the Eastern Cape Province. Three biomarkers, the acetylcholinesterase (AChE) assay, lipid peroxidation (LPx) assay, liver histopathology and a condition factor were used to determine sub-organism health and one bioindicator, the Estuarine Fish Community Index (EFCI), was used as a bioindicator of community health. The estuarine-dependent marine species Rhabdosargus holubi was selected as an indicator species for the sub-organism level analyses. The results from the community analyses indicated that the EK and OW estuaries were in 'good' condition, while the MTN was found to be in 'moderate' condition. Histological analyses revealed that R. holubi from all three estuaries showed signs of pathological changes to the liver, with the fish from the MTN eliciting the highest occurrence of these changes. The LPx assay found that R. holubi from both the OW and MTN showed signs of oxidative damage in the liver tissue, but those from the EK did not appear to be affected. The AChE assay showed that only the fish from the OW had been affected by anticholinesterase compounds. A laboratory study was undertaken using R. holubi as a positive control for the AChE and LPx assay. The fish were exposed to 3 μg/L chlorpyrifos, a known cholinesterase inhibitor, for six hours and their tissues were examined for changes to LPx levels and AChE activities. AChE activity was significantly inhibited (Mann Whitney U test, Z = 3.65, n = 38, P < 0.001) by the exposure, but LPx levels were not significantly affected. A composite index incorporating the biomarkers at different biological levels of organisation was developed. The index was designed to assist managers and scientists to determine whether the ichthyofauna of a system was being affected by environmental stressors and what management interventions could be undertaken to ameliorate the water quality in an estuary. The index was applied to the three estuaries investigated during the present study and both the OW and MTN were assessed to be in need of immediate management intervention. The fish in the OW were found to be stressed at all the sub-organism levels measured and the reason for this was hypothesised to be as a result of golf course activities in this adjacent estuary. A number of management actions are proposed to reduce the sub-organism stress observed in the fish from the OW. The livers of fish from the MTN were shown to be under stress; however the causative agent of this stress was unknown because there is no formal development in the MTN catchment. However, a possible contaminant source is proposed and management interventions to alleviate the stress on the biota of the MTN are suggested. The EK does not require immediate management intervention, however, continuous routine monitoring is recommended to ensure that conditions do not deteriorate. Shortcomings of the index were outlined and a number of suggestions were made in terms of other measures of biological health which could be incorporated into the index.
- Full Text:
- Date Issued: 2008
- Authors: Richardson, Naomi
- Date: 2008
- Subjects: Fish communities -- South Africa -- Eastern Cape Estuarine fishes -- South Africa -- Eastern Cape Estuarine health -- South Africa -- Eastern Cape Estuaries -- South Africa -- Eastern Cape -- Management Coastal zone management -- South Africa -- Eastern Cape Environmental monitoring -- South Africa -- Eastern Cape Estuarine ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5348 , http://hdl.handle.net/10962/d1007480
- Description: The aims of this study were to determine the potential use of biomarkers at multiple levels of biological organisation together with a fish community bioindicator to assess the estuarine health status of three temporarily open/closed estuaries. The estuaries investigated were the East Kleinemonde (EK), Old Woman's (OW) and Mtana (MTN), all of which are situated in the Eastern Cape Province. Three biomarkers, the acetylcholinesterase (AChE) assay, lipid peroxidation (LPx) assay, liver histopathology and a condition factor were used to determine sub-organism health and one bioindicator, the Estuarine Fish Community Index (EFCI), was used as a bioindicator of community health. The estuarine-dependent marine species Rhabdosargus holubi was selected as an indicator species for the sub-organism level analyses. The results from the community analyses indicated that the EK and OW estuaries were in 'good' condition, while the MTN was found to be in 'moderate' condition. Histological analyses revealed that R. holubi from all three estuaries showed signs of pathological changes to the liver, with the fish from the MTN eliciting the highest occurrence of these changes. The LPx assay found that R. holubi from both the OW and MTN showed signs of oxidative damage in the liver tissue, but those from the EK did not appear to be affected. The AChE assay showed that only the fish from the OW had been affected by anticholinesterase compounds. A laboratory study was undertaken using R. holubi as a positive control for the AChE and LPx assay. The fish were exposed to 3 μg/L chlorpyrifos, a known cholinesterase inhibitor, for six hours and their tissues were examined for changes to LPx levels and AChE activities. AChE activity was significantly inhibited (Mann Whitney U test, Z = 3.65, n = 38, P < 0.001) by the exposure, but LPx levels were not significantly affected. A composite index incorporating the biomarkers at different biological levels of organisation was developed. The index was designed to assist managers and scientists to determine whether the ichthyofauna of a system was being affected by environmental stressors and what management interventions could be undertaken to ameliorate the water quality in an estuary. The index was applied to the three estuaries investigated during the present study and both the OW and MTN were assessed to be in need of immediate management intervention. The fish in the OW were found to be stressed at all the sub-organism levels measured and the reason for this was hypothesised to be as a result of golf course activities in this adjacent estuary. A number of management actions are proposed to reduce the sub-organism stress observed in the fish from the OW. The livers of fish from the MTN were shown to be under stress; however the causative agent of this stress was unknown because there is no formal development in the MTN catchment. However, a possible contaminant source is proposed and management interventions to alleviate the stress on the biota of the MTN are suggested. The EK does not require immediate management intervention, however, continuous routine monitoring is recommended to ensure that conditions do not deteriorate. Shortcomings of the index were outlined and a number of suggestions were made in terms of other measures of biological health which could be incorporated into the index.
- Full Text:
- Date Issued: 2008
The underreporting of sexual violence against women in the Camdeboo
- Authors: Luyt, Derek
- Date: 2008
- Subjects: Women -- Violence against -- South Africa -- Camdeboo, Plains of Abused women -- South Africa -- Camdeboo, Plains of Sexual abuse victims -- South Africa -- Camdeboo, Plains of Camdeboo, Plains of (South Africa)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2796 , http://hdl.handle.net/10962/d1003006
- Description: This thesis examines the underreporting of sexual violence against women in the Camdeboo. It is based on a survey of 971 women living in the Camdeboo aged fifteen and older. The thesis considers, with reference to relevant secondary literature, methodological issues pertinent to conducting survey research into violence against women. While many survey researchers into violence against women argue that behaviourally specific questions lead to higher rates of disclosure, the survey on which this thesis is based employed complex and open-ended questions to allow respondents to record their own definitions of physical and sexual abuse. 31,2 percent of the women surveyed disclosed having experienced sexual abuse, but 76,7 percent did not report this abuse to the police. The thesis explores the patterns of sexual abuse of women in the Camdeboo and the factors influencing the underreporting of such abuse. While it was possible to establish correlations between certain socio-demographic variables and the underreporting of sexual abuse, such correlations should be treated with caution. The survey found that women were far more likely to report (and disclose) sexual assaults by strangers than by people known to them, particularly intimate partners. Sexual abuse in intimate relations was found to be strongly associated with physical abuse, and women who had experienced sexual and physical abuse within intimate relationships were more likely to report their physical abuse to the police than their sexual abuse. However, the majority of women, particularly poor and economically dependent women, believed that reporting their intimate partner abuse to the police would not end it, and might even place them at greater risk. The evidence suggests that these perceptions are accurate. Under current circumstances, reporting sexual abuse to the police may not be the best help-seeking strategy available to many sexually abused women, and alternative sources of help may be more appropriate. Consideration should be given to directing more resources into such alternatives.
- Full Text:
- Date Issued: 2008
- Authors: Luyt, Derek
- Date: 2008
- Subjects: Women -- Violence against -- South Africa -- Camdeboo, Plains of Abused women -- South Africa -- Camdeboo, Plains of Sexual abuse victims -- South Africa -- Camdeboo, Plains of Camdeboo, Plains of (South Africa)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2796 , http://hdl.handle.net/10962/d1003006
- Description: This thesis examines the underreporting of sexual violence against women in the Camdeboo. It is based on a survey of 971 women living in the Camdeboo aged fifteen and older. The thesis considers, with reference to relevant secondary literature, methodological issues pertinent to conducting survey research into violence against women. While many survey researchers into violence against women argue that behaviourally specific questions lead to higher rates of disclosure, the survey on which this thesis is based employed complex and open-ended questions to allow respondents to record their own definitions of physical and sexual abuse. 31,2 percent of the women surveyed disclosed having experienced sexual abuse, but 76,7 percent did not report this abuse to the police. The thesis explores the patterns of sexual abuse of women in the Camdeboo and the factors influencing the underreporting of such abuse. While it was possible to establish correlations between certain socio-demographic variables and the underreporting of sexual abuse, such correlations should be treated with caution. The survey found that women were far more likely to report (and disclose) sexual assaults by strangers than by people known to them, particularly intimate partners. Sexual abuse in intimate relations was found to be strongly associated with physical abuse, and women who had experienced sexual and physical abuse within intimate relationships were more likely to report their physical abuse to the police than their sexual abuse. However, the majority of women, particularly poor and economically dependent women, believed that reporting their intimate partner abuse to the police would not end it, and might even place them at greater risk. The evidence suggests that these perceptions are accurate. Under current circumstances, reporting sexual abuse to the police may not be the best help-seeking strategy available to many sexually abused women, and alternative sources of help may be more appropriate. Consideration should be given to directing more resources into such alternatives.
- Full Text:
- Date Issued: 2008
Melatonin and anticancer therapy interactions with 5-Fluorouracil
- Authors: Cassim, Layla
- Date: 2008
- Subjects: Melatonin Melatonin -- Therapeutic use Antineoplastic agents Fluorouracil Fluorouracil -- Toxicology Cancer -- Treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3746 , http://hdl.handle.net/10962/d1003224
- Description: On the basis of clinical studies, some researchers have advocated that the neurohormone and antioxidant melatonin, shown to possess intrinsic anticancer properties, be used as co-therapy in cancer patients being treated with the antineoplastic agent 5-fluorouracil, as increased patient survival times and enhanced quality of life have been observed. The focus of this research was thus to investigate the mechanisms of this seemingly beneficial drug interaction between 5-fluorouracil and melatonin. Metabolism studies were undertaken, in which it was established that there is no hepatic metabolic drug interaction between these agents by cytochrome P450, and that neither agent alters the activity of this enzyme system. Co-therapy with melatonin is thus unlikely to alter plasma levels of 5-fluorouracil by this mechanism. Novel mechanisms by which 5-fluorouracil is toxic were elucidated, such as the induction of lipid peroxidation, due to the formation of reactive oxygen species; decreases in brain serotonin, dopamine and norepinephrine levels, possibly leading to depression; hippocampal shrinkage and morphological alterations and lysis of hippocampal cells, which may underlie cognitive impairment; and a reduction in the nociceptive threshold when administered acutely. All these deleterious effects are attenuated by the co-administration of melatonin, suggesting that the agent exhibits antidepressive and analgesic properties, in addition to its known antioxidative and free radical-scavenging abilities. This suggests that melatonin cotherapy can significantly decrease 5-fluorouracil-induced toxicity, but this may also exert a protective effect on cancer cells and thus compromise the anticancer efficacy of 5-fluorouracil. It was, furthermore, found that stimulation of indoleamine 2,3-dioxygenase activity, mediated by increases in superoxide anion and interferon-γ levels, may underlie resistance to 5-fluorouracil therapy. Melatonin was shown to increase superoxide anion levels in vivo, and this is believed to be by conversion to the metabolite and known oxidant 6- hydroxymelatonin. This highlights that the possible deleterious effects of melatonin metabolites should be studied further. Serum corticosterone levels and cytokine profiles are unaltered by both 5-FU and melatonin, suggesting that these agents may be used by HIV infected individuals without promoting the progression to AIDS. It can thus be concluded that melatonin co-therapy is potentially useful in countering 5-fluorouracil toxicity.
- Full Text:
- Date Issued: 2008
- Authors: Cassim, Layla
- Date: 2008
- Subjects: Melatonin Melatonin -- Therapeutic use Antineoplastic agents Fluorouracil Fluorouracil -- Toxicology Cancer -- Treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3746 , http://hdl.handle.net/10962/d1003224
- Description: On the basis of clinical studies, some researchers have advocated that the neurohormone and antioxidant melatonin, shown to possess intrinsic anticancer properties, be used as co-therapy in cancer patients being treated with the antineoplastic agent 5-fluorouracil, as increased patient survival times and enhanced quality of life have been observed. The focus of this research was thus to investigate the mechanisms of this seemingly beneficial drug interaction between 5-fluorouracil and melatonin. Metabolism studies were undertaken, in which it was established that there is no hepatic metabolic drug interaction between these agents by cytochrome P450, and that neither agent alters the activity of this enzyme system. Co-therapy with melatonin is thus unlikely to alter plasma levels of 5-fluorouracil by this mechanism. Novel mechanisms by which 5-fluorouracil is toxic were elucidated, such as the induction of lipid peroxidation, due to the formation of reactive oxygen species; decreases in brain serotonin, dopamine and norepinephrine levels, possibly leading to depression; hippocampal shrinkage and morphological alterations and lysis of hippocampal cells, which may underlie cognitive impairment; and a reduction in the nociceptive threshold when administered acutely. All these deleterious effects are attenuated by the co-administration of melatonin, suggesting that the agent exhibits antidepressive and analgesic properties, in addition to its known antioxidative and free radical-scavenging abilities. This suggests that melatonin cotherapy can significantly decrease 5-fluorouracil-induced toxicity, but this may also exert a protective effect on cancer cells and thus compromise the anticancer efficacy of 5-fluorouracil. It was, furthermore, found that stimulation of indoleamine 2,3-dioxygenase activity, mediated by increases in superoxide anion and interferon-γ levels, may underlie resistance to 5-fluorouracil therapy. Melatonin was shown to increase superoxide anion levels in vivo, and this is believed to be by conversion to the metabolite and known oxidant 6- hydroxymelatonin. This highlights that the possible deleterious effects of melatonin metabolites should be studied further. Serum corticosterone levels and cytokine profiles are unaltered by both 5-FU and melatonin, suggesting that these agents may be used by HIV infected individuals without promoting the progression to AIDS. It can thus be concluded that melatonin co-therapy is potentially useful in countering 5-fluorouracil toxicity.
- Full Text:
- Date Issued: 2008
Barriers and drivers to the implementation of the "clean development mechanism" within the Nelson Mandela Bay Municipality: a case study
- Authors: Wilson, Craig Michael
- Date: 2008
- Subjects: Nelson Mandela Metropolitan Municipality (Eastern Cape, South Africa) Local government -- South Africa -- Eastern Cape -- Case studies Climatic changes -- South Africa -- Eastern Cape -- Case studies Greenhouse gases -- Environmental aspects -- South Africa -- Eastern Cape -- Case studies Environmental economics -- South Africa -- Eastern Cape -- Case studies Greenhouse effect, Atmospheric Global warming
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:731 , http://hdl.handle.net/10962/d1003851
- Description: The global threat of climate change is one of the most crucial environmental issues facing the world in modern times. In response to this threat, international governments have drafted the Kyoto Protocol which included the Clean Development Mechanism (CDM). The CDM is a scheme which invited developing countries, like South Africa, to become involved in climate change mitigation projects. While South Africa has been identified as an attractive host country for CDM projects, research has revealed that it lags behind other developing countries in this regard. This study provides a theoretical background to the CDM and grounds the subject within the field of Environmental Economics. Following a literature review of factors that could influence the involvement of a municipality in CDM projects, this thesis undertook a case study of the barriers and drivers to CDM implementation within the Nelson Mandela Bay Municipality (NMBM). Use was made of semi-structured interviews, where a questionnaire was used to guide the researcher’s interview process. Five NMBM officers, who were likely to have been involved with CDM project implementation, were interviewed. Data collected was analyzed using a coding technique and was compared and contrasted to the literature in a process of explanation building. It was possible to elicit 14 factors that acted as CDM-barriers; seven that acted as CDM-drivers; and 10 that were required to change within the NMBM to encourage greater CDM involvement. Of the barriers, lack of awareness, poor political will and lack of funding emerged as the most inhibiting. Of the CDM-drivers, the potential financial benefits; ownership of infrastructure capable of producing carbon assets; and technology transfer emerged as the factors most likely to promote CDM involvement. With regards the factors that require change, it emerged that a positive response would result from a proactive stance by National Government on the CDM; the use of Public-Private-Partnerships to facilitate CDM projects; and improved communication and capacity building within the NMBM and the Nelson Mandela Bay business community. The main recommendation offered to the NMBM was for it to draft a Sustainable Development Policy as well as a formal sustainable development strategy to drive a coherent and consolidated approach to the Municipality’s involvement with CDM projects. Further, it was proposed that the NMBM should, lobby National Government for it to promulgate enabling legislation and a framework which would encourage CDM investment in South Africa; and engage with local business to promote the active involvement of the Nelson Mandela Bay with the implementation of CDM projects. Keywords: Global Warming, Kyoto Protocol, Clean Development Mechanism, Sustainable Development, Environmental Economics, Public Sector, Nelson Mandela Bay Municipality.
- Full Text:
- Date Issued: 2008
- Authors: Wilson, Craig Michael
- Date: 2008
- Subjects: Nelson Mandela Metropolitan Municipality (Eastern Cape, South Africa) Local government -- South Africa -- Eastern Cape -- Case studies Climatic changes -- South Africa -- Eastern Cape -- Case studies Greenhouse gases -- Environmental aspects -- South Africa -- Eastern Cape -- Case studies Environmental economics -- South Africa -- Eastern Cape -- Case studies Greenhouse effect, Atmospheric Global warming
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:731 , http://hdl.handle.net/10962/d1003851
- Description: The global threat of climate change is one of the most crucial environmental issues facing the world in modern times. In response to this threat, international governments have drafted the Kyoto Protocol which included the Clean Development Mechanism (CDM). The CDM is a scheme which invited developing countries, like South Africa, to become involved in climate change mitigation projects. While South Africa has been identified as an attractive host country for CDM projects, research has revealed that it lags behind other developing countries in this regard. This study provides a theoretical background to the CDM and grounds the subject within the field of Environmental Economics. Following a literature review of factors that could influence the involvement of a municipality in CDM projects, this thesis undertook a case study of the barriers and drivers to CDM implementation within the Nelson Mandela Bay Municipality (NMBM). Use was made of semi-structured interviews, where a questionnaire was used to guide the researcher’s interview process. Five NMBM officers, who were likely to have been involved with CDM project implementation, were interviewed. Data collected was analyzed using a coding technique and was compared and contrasted to the literature in a process of explanation building. It was possible to elicit 14 factors that acted as CDM-barriers; seven that acted as CDM-drivers; and 10 that were required to change within the NMBM to encourage greater CDM involvement. Of the barriers, lack of awareness, poor political will and lack of funding emerged as the most inhibiting. Of the CDM-drivers, the potential financial benefits; ownership of infrastructure capable of producing carbon assets; and technology transfer emerged as the factors most likely to promote CDM involvement. With regards the factors that require change, it emerged that a positive response would result from a proactive stance by National Government on the CDM; the use of Public-Private-Partnerships to facilitate CDM projects; and improved communication and capacity building within the NMBM and the Nelson Mandela Bay business community. The main recommendation offered to the NMBM was for it to draft a Sustainable Development Policy as well as a formal sustainable development strategy to drive a coherent and consolidated approach to the Municipality’s involvement with CDM projects. Further, it was proposed that the NMBM should, lobby National Government for it to promulgate enabling legislation and a framework which would encourage CDM investment in South Africa; and engage with local business to promote the active involvement of the Nelson Mandela Bay with the implementation of CDM projects. Keywords: Global Warming, Kyoto Protocol, Clean Development Mechanism, Sustainable Development, Environmental Economics, Public Sector, Nelson Mandela Bay Municipality.
- Full Text:
- Date Issued: 2008
Network-layer reservation TDM for ad-hoc 802.11 networks
- Authors: Duff, Kevin Craig
- Date: 2008
- Subjects: Computer networks -- Access control , Computers -- Access control , Computer networks -- Management , Time division multiple access , Ad hoc networks (Computer networks)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4574 , http://hdl.handle.net/10962/d1002773 , Computer networks -- Access control , Computers -- Access control , Computer networks -- Management , Time division multiple access , Ad hoc networks (Computer networks)
- Description: Ad-Hoc mesh networks offer great promise. Low-cost ad-hoc mesh networks can be built using popular IEEE 802.11 equipment, but such networks are unable to guarantee each node a fair share of bandwidth. Furthermore, hidden node problems cause collisions which can cripple the throughput of a network. This research proposes a novel mechanism which is able to overcome hidden node problems and provide fair bandwidth sharing among nodes on ad-hoc 802.11 networks, and can be implemented on existing network devices. The scheme uses TDM (time division multiplexing) with slot reservation. A distributed beacon packet latency measurement mechanism is used to achieve node synchronisation. The distributed nature of the mechanism makes it applicable to ad-hoc 802.11 networks, which can either grow or fragment dynamically.
- Full Text:
- Date Issued: 2008
- Authors: Duff, Kevin Craig
- Date: 2008
- Subjects: Computer networks -- Access control , Computers -- Access control , Computer networks -- Management , Time division multiple access , Ad hoc networks (Computer networks)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4574 , http://hdl.handle.net/10962/d1002773 , Computer networks -- Access control , Computers -- Access control , Computer networks -- Management , Time division multiple access , Ad hoc networks (Computer networks)
- Description: Ad-Hoc mesh networks offer great promise. Low-cost ad-hoc mesh networks can be built using popular IEEE 802.11 equipment, but such networks are unable to guarantee each node a fair share of bandwidth. Furthermore, hidden node problems cause collisions which can cripple the throughput of a network. This research proposes a novel mechanism which is able to overcome hidden node problems and provide fair bandwidth sharing among nodes on ad-hoc 802.11 networks, and can be implemented on existing network devices. The scheme uses TDM (time division multiplexing) with slot reservation. A distributed beacon packet latency measurement mechanism is used to achieve node synchronisation. The distributed nature of the mechanism makes it applicable to ad-hoc 802.11 networks, which can either grow or fragment dynamically.
- Full Text:
- Date Issued: 2008
South Africa and Malaysia: identity and history in South-South relations
- Authors: Haron, Muhammed
- Date: 2008
- Subjects: Critical theory South Africa -- Foreign relations -- Malaysia Malaysia -- Foreign relations -- South Africa South Africa -- Politics and government -- History Malaysia -- Politics and government -- History South Africa -- Politics and government Malaysia -- Politics and government South Africa -- Social conditions -- History Malaysia -- Social conditions -- History South Africa -- Economic conditions Malaysia -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2780 , http://hdl.handle.net/10962/d1002990
- Description: The focus of this thesis is on the bilateral relationship between South Africa and Malaysia. The thesis appropriates ‘critical theory,’ and as a flexible theoretical tool, and, as an open-ended, loose frame in order to give voice to the marginalized and voiceless from the South. The thesis thus looks at the politico-economic ties that have been developed and brings into view the socio-cultural relations that had been established between the peoples of the two sovereign nation-states during the apartheid and post-apartheid eras respectively. The basic purpose of this study was fivefold: (a) to contribute to the extant literature that concentrates on South Africa’s relations with Malaysia, (b) to examine the relationship at political and economic ties in some detail, (c) to demonstrate that apart from the afore-mentioned bonds IR specialists should also take into account the socio-cultural dimensions of international relations, (d) to bring to light the nation-state’s limitations when discussing the role of non-state actors and considering the contributions of other factors such as globalization, and (e) to stimulate further research on bilateral and multilateral relations in the South – particularly between South Africa and other states in Asia and Latin America - that would assist to better understand the past, present and perhaps the future.
- Full Text:
- Date Issued: 2008
- Authors: Haron, Muhammed
- Date: 2008
- Subjects: Critical theory South Africa -- Foreign relations -- Malaysia Malaysia -- Foreign relations -- South Africa South Africa -- Politics and government -- History Malaysia -- Politics and government -- History South Africa -- Politics and government Malaysia -- Politics and government South Africa -- Social conditions -- History Malaysia -- Social conditions -- History South Africa -- Economic conditions Malaysia -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2780 , http://hdl.handle.net/10962/d1002990
- Description: The focus of this thesis is on the bilateral relationship between South Africa and Malaysia. The thesis appropriates ‘critical theory,’ and as a flexible theoretical tool, and, as an open-ended, loose frame in order to give voice to the marginalized and voiceless from the South. The thesis thus looks at the politico-economic ties that have been developed and brings into view the socio-cultural relations that had been established between the peoples of the two sovereign nation-states during the apartheid and post-apartheid eras respectively. The basic purpose of this study was fivefold: (a) to contribute to the extant literature that concentrates on South Africa’s relations with Malaysia, (b) to examine the relationship at political and economic ties in some detail, (c) to demonstrate that apart from the afore-mentioned bonds IR specialists should also take into account the socio-cultural dimensions of international relations, (d) to bring to light the nation-state’s limitations when discussing the role of non-state actors and considering the contributions of other factors such as globalization, and (e) to stimulate further research on bilateral and multilateral relations in the South – particularly between South Africa and other states in Asia and Latin America - that would assist to better understand the past, present and perhaps the future.
- Full Text:
- Date Issued: 2008
The development of a putative microbial product for use in crop production
- Authors: Gumede, Halalisani
- Date: 2008
- Subjects: Agricultural productivity , Agriculture -- Economic aspects , Microbial products , Bacterial diseases of plants , Biological pest control agents , Lettuce -- Diseases and pests , Crops -- Nutrition , Bacillus (Bacteria) , Phytopathogenic microorganisms -- Control
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3945 , http://hdl.handle.net/10962/d1004004 , Agricultural productivity , Agriculture -- Economic aspects , Microbial products , Bacterial diseases of plants , Biological pest control agents , Lettuce -- Diseases and pests , Crops -- Nutrition , Bacillus (Bacteria) , Phytopathogenic microorganisms -- Control
- Description: The challenges faced by the agricultural sector especially around improving production yields using environmentally friendly solutions have received market attention. Biological intervention can range from application of biological products to enhance the nutritional value of crops or to control plant pathogens. Biostart, a biological product that demonstrated growth enhancement when applied in lettuce crops is currently in the market. The product is comprised of a consortium of bacterial isolates (Bacillus licheniformis, Brevibacillus laterosporus and Bacillus laterosporus) but the contribution of the individual isolates to growth enhancement had not been elucidated. Green house experiments on lettuce seedlings with individual and mixed treatments were commissioned to determine such contribution. There was either no or marginal growth enhancement observed in the experiments. The results showed that the product was effective as a consortium and not as individual isolates. Further isolation and screening for potential Bacilli with antifungal properties was undertaken. An isolate identified as Bacillus subtilis that demonstrated inhibition against a wide spectrum of fungi, and especially the phytopathogenic Verticillium dahliae and Fusarium oxysporum, was successfully identified. The isolate was cryo-preserved and cultivated to significant levels at bench scale. A characterized comparison of different putative products with known systematic fungicide showed potential application even of heat treated products. The product showed control V. dahliae when tested in green houses with potatoes and tomatoes as test crops. This isolate has been targeted for further development as a biological control product.
- Full Text:
- Date Issued: 2008
- Authors: Gumede, Halalisani
- Date: 2008
- Subjects: Agricultural productivity , Agriculture -- Economic aspects , Microbial products , Bacterial diseases of plants , Biological pest control agents , Lettuce -- Diseases and pests , Crops -- Nutrition , Bacillus (Bacteria) , Phytopathogenic microorganisms -- Control
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3945 , http://hdl.handle.net/10962/d1004004 , Agricultural productivity , Agriculture -- Economic aspects , Microbial products , Bacterial diseases of plants , Biological pest control agents , Lettuce -- Diseases and pests , Crops -- Nutrition , Bacillus (Bacteria) , Phytopathogenic microorganisms -- Control
- Description: The challenges faced by the agricultural sector especially around improving production yields using environmentally friendly solutions have received market attention. Biological intervention can range from application of biological products to enhance the nutritional value of crops or to control plant pathogens. Biostart, a biological product that demonstrated growth enhancement when applied in lettuce crops is currently in the market. The product is comprised of a consortium of bacterial isolates (Bacillus licheniformis, Brevibacillus laterosporus and Bacillus laterosporus) but the contribution of the individual isolates to growth enhancement had not been elucidated. Green house experiments on lettuce seedlings with individual and mixed treatments were commissioned to determine such contribution. There was either no or marginal growth enhancement observed in the experiments. The results showed that the product was effective as a consortium and not as individual isolates. Further isolation and screening for potential Bacilli with antifungal properties was undertaken. An isolate identified as Bacillus subtilis that demonstrated inhibition against a wide spectrum of fungi, and especially the phytopathogenic Verticillium dahliae and Fusarium oxysporum, was successfully identified. The isolate was cryo-preserved and cultivated to significant levels at bench scale. A characterized comparison of different putative products with known systematic fungicide showed potential application even of heat treated products. The product showed control V. dahliae when tested in green houses with potatoes and tomatoes as test crops. This isolate has been targeted for further development as a biological control product.
- Full Text:
- Date Issued: 2008
A study of the Amathole District Municipality's settlement plan in the light of the land reform and spatial planning measures
- Authors: Zenzile, Mlamli Lennox
- Date: 2008
- Subjects: Land reform -- South Africa -- Eastern Cape , Land tenure -- South Africa -- Eastern Cape , Land settlement -- Government policy -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Municipal government -- South Africa -- Eastern Cape , Land use -- Planning -- South Africa , Restitution -- South Africa -- Eastern Cape , Compensation (Law) -- South Africa -- Eastern Cape , Human rights -- South Africa -- Eastern Cape , Right of property -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3700 , http://hdl.handle.net/10962/d1003215 , Land reform -- South Africa -- Eastern Cape , Land tenure -- South Africa -- Eastern Cape , Land settlement -- Government policy -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Municipal government -- South Africa -- Eastern Cape , Land use -- Planning -- South Africa , Restitution -- South Africa -- Eastern Cape , Compensation (Law) -- South Africa -- Eastern Cape , Human rights -- South Africa -- Eastern Cape , Right of property -- South Africa -- Eastern Cape
- Description: This study concerns the analysis of policy, and the statutory and regulatory impact of spatial planning on the land reform programme with emphasis on the land reform settlement plan (LSRP) of the Amathole District Municipality (ADM). There is a brief historical overview of the effect of the policy of spatial segregation in both rural and urban areas of the ADM. This study demonstrates, inter alia, the challenges faced by the ADM in both consolidating and physically integrating communities that were hitherto divided across racial lines. The critical question is whether the ADM has the ability to produce a Spatial Development Framework (SDF), which will be responsive to the needs of the region and serve as a catalyst in reversing the physical distortions caused by the land-planning legislation of the apartheid past. The greatest challenge lies in meeting the developmental aspirations of the Development Facilitation Act, 1995, the Local Government: Municipal Systems Act, 2000 and the National Spatial Development Perspective, 2003. Chapter 1 deals with the purpose, research problem and the method of research, as well as the definition of terms used in this research and literature review. Chapter 2 deals with the evolution of central themes of spatial planning and land reform, spatial development plans and integrated development plans (IDPs), the alignment of Amathole SDF and Eastern Cape Spatial Development Plan and the co-ordination of spatial frameworks. Chapter 3 deals with the composition of the ADM and the evolution of the LRSP, as well as land-tenure reform programmes impacting on the Amathole Municipality region. This chapter analyses the settlement plan against spatial planning legislation, the issue of institutional arrangements and mechanisms of consolidated local planning processes. Chapter 5 deals with the thorny issue of participation of traditional leaders in municipal planning and the government’s land-reform programme. Despite the existence of legislation in this regard, implementation seems to pose some difficulties. This chapter also deals with the co-operative governance framework. Chapter 6 is a concluding chapter dealing with the gaps discovered in the Amathole Municipality in the light of existing legislation. Reference to cases is made to demonstrate the challenges confronting the ADM. One notable aspect is the issue of urban-rural dichotomy and how the two worlds are positioned in their competition for the use of space. It is evident from this research that the post-1994 policy and legislative framework and implementation machinery lacks capacity to change the current form of the apartheid city-planning paradigm, something which impacts immensely on the sustainability of the current human-settlement development programmes. Population dynamics in terms of migration are hugely driven by search for employment opportunities and better services. The efficiency and ability of the municipal spatial evelopment frameworks in directing and dictating the identification of development nodes in its juristic boundary informed by the overarching national policy and legislative framework is key in building a better South Africa.
- Full Text:
- Date Issued: 2008
- Authors: Zenzile, Mlamli Lennox
- Date: 2008
- Subjects: Land reform -- South Africa -- Eastern Cape , Land tenure -- South Africa -- Eastern Cape , Land settlement -- Government policy -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Municipal government -- South Africa -- Eastern Cape , Land use -- Planning -- South Africa , Restitution -- South Africa -- Eastern Cape , Compensation (Law) -- South Africa -- Eastern Cape , Human rights -- South Africa -- Eastern Cape , Right of property -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:3700 , http://hdl.handle.net/10962/d1003215 , Land reform -- South Africa -- Eastern Cape , Land tenure -- South Africa -- Eastern Cape , Land settlement -- Government policy -- South Africa -- Eastern Cape , Local government -- South Africa -- Eastern Cape , Municipal government -- South Africa -- Eastern Cape , Land use -- Planning -- South Africa , Restitution -- South Africa -- Eastern Cape , Compensation (Law) -- South Africa -- Eastern Cape , Human rights -- South Africa -- Eastern Cape , Right of property -- South Africa -- Eastern Cape
- Description: This study concerns the analysis of policy, and the statutory and regulatory impact of spatial planning on the land reform programme with emphasis on the land reform settlement plan (LSRP) of the Amathole District Municipality (ADM). There is a brief historical overview of the effect of the policy of spatial segregation in both rural and urban areas of the ADM. This study demonstrates, inter alia, the challenges faced by the ADM in both consolidating and physically integrating communities that were hitherto divided across racial lines. The critical question is whether the ADM has the ability to produce a Spatial Development Framework (SDF), which will be responsive to the needs of the region and serve as a catalyst in reversing the physical distortions caused by the land-planning legislation of the apartheid past. The greatest challenge lies in meeting the developmental aspirations of the Development Facilitation Act, 1995, the Local Government: Municipal Systems Act, 2000 and the National Spatial Development Perspective, 2003. Chapter 1 deals with the purpose, research problem and the method of research, as well as the definition of terms used in this research and literature review. Chapter 2 deals with the evolution of central themes of spatial planning and land reform, spatial development plans and integrated development plans (IDPs), the alignment of Amathole SDF and Eastern Cape Spatial Development Plan and the co-ordination of spatial frameworks. Chapter 3 deals with the composition of the ADM and the evolution of the LRSP, as well as land-tenure reform programmes impacting on the Amathole Municipality region. This chapter analyses the settlement plan against spatial planning legislation, the issue of institutional arrangements and mechanisms of consolidated local planning processes. Chapter 5 deals with the thorny issue of participation of traditional leaders in municipal planning and the government’s land-reform programme. Despite the existence of legislation in this regard, implementation seems to pose some difficulties. This chapter also deals with the co-operative governance framework. Chapter 6 is a concluding chapter dealing with the gaps discovered in the Amathole Municipality in the light of existing legislation. Reference to cases is made to demonstrate the challenges confronting the ADM. One notable aspect is the issue of urban-rural dichotomy and how the two worlds are positioned in their competition for the use of space. It is evident from this research that the post-1994 policy and legislative framework and implementation machinery lacks capacity to change the current form of the apartheid city-planning paradigm, something which impacts immensely on the sustainability of the current human-settlement development programmes. Population dynamics in terms of migration are hugely driven by search for employment opportunities and better services. The efficiency and ability of the municipal spatial evelopment frameworks in directing and dictating the identification of development nodes in its juristic boundary informed by the overarching national policy and legislative framework is key in building a better South Africa.
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- Date Issued: 2008