A critical ethnographic study of report writing as a literacy practice by automotive engineers
- Authors: Harran, Marcelle
- Date: 2007
- Subjects: English language -- Written English -- South Africa Written communication -- South Africa Literacy -- Social aspects -- South Africa Engineers -- Language -- South Africa Communication in engineering -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1476 , http://hdl.handle.net/10962/d1003357
- Description: This study describes the social practices involved in the situated activity of report writing in an engineering automotive discourse community in South Africa. In particular, the study focuses on the subjectivity of predominantly English Second Language (ESL) engineers writing reports by determining what literacy means to them and what meanings they give to dominant literacy practices in report writing, especially feedback in text production. In the South African engineering workplace, because of the diversity and complexity of language and identity issues, the appropriation of the required literacy skills tends to be multifaceted. This context is made more complex as English is the business language upon which engineering is based with engineering competence often related to English proficiency. Therefore, the study is located within the understanding that literacy is always situated within specific discoursal practices whose ideologies, beliefs, power relations, values and identities are manifested rhetorically. The basis for this critical theory of literacy is the assertion that literacy is a social practice which involves not only observable units of behaviour but values, attitudes, feelings and social relationships. As the institution’s socio-cultural context in the form of embedded historical and institutional forces impact on writer identity and writing practices or ways of doing report writing, notions of writing as a transparent and autonomous system are also challenged. As critical ethnography is concerned with multiple perspectives, it was selected as the preferred methodology and critical realism to derive definitions of truth and validity. Critical ethnography explores cultural orientations of local practice contexts and incorporates multiple understandings providing a holistic understanding of the complexity of writing practices. As human experience can only be known under particular descriptions, usually in terms of available discourses such as language, writing and rhetoric, the dominant practices emerging in response to the report acceptance event are explored, especially that of supervisor feedback practices as they causally impact on report-writing practices during the practice of report acceptance. Although critical realism does not necessarily demonstrate successful causal explanations, it does look for substantial relations within wider contexts to illuminate part-whole relationships. Therefore, an attempt is made to find representativeness or fit with situated engineering literacy practices and wider and changing literacy contexts, especially the impact of Higher Education and world Englishes as well as the expanding influence of technological and digital systems on report-writing practices.
- Full Text:
- Date Issued: 2007
- Authors: Harran, Marcelle
- Date: 2007
- Subjects: English language -- Written English -- South Africa Written communication -- South Africa Literacy -- Social aspects -- South Africa Engineers -- Language -- South Africa Communication in engineering -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1476 , http://hdl.handle.net/10962/d1003357
- Description: This study describes the social practices involved in the situated activity of report writing in an engineering automotive discourse community in South Africa. In particular, the study focuses on the subjectivity of predominantly English Second Language (ESL) engineers writing reports by determining what literacy means to them and what meanings they give to dominant literacy practices in report writing, especially feedback in text production. In the South African engineering workplace, because of the diversity and complexity of language and identity issues, the appropriation of the required literacy skills tends to be multifaceted. This context is made more complex as English is the business language upon which engineering is based with engineering competence often related to English proficiency. Therefore, the study is located within the understanding that literacy is always situated within specific discoursal practices whose ideologies, beliefs, power relations, values and identities are manifested rhetorically. The basis for this critical theory of literacy is the assertion that literacy is a social practice which involves not only observable units of behaviour but values, attitudes, feelings and social relationships. As the institution’s socio-cultural context in the form of embedded historical and institutional forces impact on writer identity and writing practices or ways of doing report writing, notions of writing as a transparent and autonomous system are also challenged. As critical ethnography is concerned with multiple perspectives, it was selected as the preferred methodology and critical realism to derive definitions of truth and validity. Critical ethnography explores cultural orientations of local practice contexts and incorporates multiple understandings providing a holistic understanding of the complexity of writing practices. As human experience can only be known under particular descriptions, usually in terms of available discourses such as language, writing and rhetoric, the dominant practices emerging in response to the report acceptance event are explored, especially that of supervisor feedback practices as they causally impact on report-writing practices during the practice of report acceptance. Although critical realism does not necessarily demonstrate successful causal explanations, it does look for substantial relations within wider contexts to illuminate part-whole relationships. Therefore, an attempt is made to find representativeness or fit with situated engineering literacy practices and wider and changing literacy contexts, especially the impact of Higher Education and world Englishes as well as the expanding influence of technological and digital systems on report-writing practices.
- Full Text:
- Date Issued: 2007
Invasion of Lantana into India: analyzing introduction, spread, human adaptations and management
- Hari Krishnan, Ramesh Kannan
- Authors: Hari Krishnan, Ramesh Kannan
- Date: 2013
- Subjects: Lantana -- India Weeds -- Control -- India Plant introduction -- India Natural resources -- India Botany, Economic -- India Botany -- Social aspects -- India
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4728 , http://hdl.handle.net/10962/d1001756
- Description: Objectives and Research Questions 1. To reconstruct the history of invasion of Lantana in India from where, by who, and when was Lantana species introduced into India?, given its long history in the country, is it still spreading or has it become more or less stable? 2. To study the human adaptation to Lantana invasion: socioeconomic causes and consequences of the use of Lantana as an alternative source of livelihood for forest dependent communities in southern India; how have local communities adapted to the invasion?; what are the key determinants that may have driven communities to use Lantana?; what are the economic consequences of the use of Lantana by local communities? 3. To critically review local practices and forest policy for the management of Lantana in southern India.; how has the use of Lantana by local communities impacted its local regeneration?; does the use of Lantana in local context have implications for its management?; what has been the role of the Forest Department and its policies in managing Lantana?
- Full Text:
- Date Issued: 2013
- Authors: Hari Krishnan, Ramesh Kannan
- Date: 2013
- Subjects: Lantana -- India Weeds -- Control -- India Plant introduction -- India Natural resources -- India Botany, Economic -- India Botany -- Social aspects -- India
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4728 , http://hdl.handle.net/10962/d1001756
- Description: Objectives and Research Questions 1. To reconstruct the history of invasion of Lantana in India from where, by who, and when was Lantana species introduced into India?, given its long history in the country, is it still spreading or has it become more or less stable? 2. To study the human adaptation to Lantana invasion: socioeconomic causes and consequences of the use of Lantana as an alternative source of livelihood for forest dependent communities in southern India; how have local communities adapted to the invasion?; what are the key determinants that may have driven communities to use Lantana?; what are the economic consequences of the use of Lantana by local communities? 3. To critically review local practices and forest policy for the management of Lantana in southern India.; how has the use of Lantana by local communities impacted its local regeneration?; does the use of Lantana in local context have implications for its management?; what has been the role of the Forest Department and its policies in managing Lantana?
- Full Text:
- Date Issued: 2013
Biology and systematics of some southern African myrmeleontoid insects (order Neuroptera)
- Authors: Mansell, Mervyn W
- Date: 1979
- Subjects: Ant lions -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5594 , http://hdl.handle.net/10962/d1002044
- Description: The biology of southern African Myrmeleontidae and Nemopteridae (Neuroptera, Myrmeleontoidea) was studied with special emphasis on the nemopterid subfamily Crocinae. The superfamily Myrmeleontoidea is considered to be a monophyletic group derived from ancestors similar to the family Nymphidae. The Myrmeleontidae and Nemopteridae are the most highly evolved families, and the Nemopteridae have a sistergroup relationship with the other four myrmeleontoid families. Within the Nemopteridae, the Crocinae are considered more advanced than the subfamily Nemopterinae. An account of previous work on the two families is presented: literature relating to the Myrmeleontidae is catalogued in appendix 2 and publications dealing with the Nemopteridae are surveyed in the text . Biological and morphological information derived from the immature stages as well as the adults was used in the systematic study of the two families. The geographical distribution and phylogeny of the Myrmeleontoidea is discussed with particular reference to the Myrmeleontidae and Nemopteridae. The Myrmeleontidae have a world wide distribution whilst the Nemopteridae are more restricted, being limited to the arid and semi-arid regions of the world. It is concluded that the two families originated on Gondwanaland, and their present distribution is explained on the basis of evidence provided by plate tectonics. In southern Africa, the Myrmeleontidae show two distributional trends: there is a distinct western fauna including many endemics and an eastern fauna which comprises taxa with a wide distribution in central and east Africa, extending their ranges into the eastern parts of the subregion. The Nemopteridae occur predominantly on the western side of the subcontinent and over 90% of the species are endemic to southern Africa. A systematic revision of the southern African Crocinae is presented and summarized in a set of illustrated keys to the adults and larvae. There are now ten known crocin species in four genera from the subregion, four species being described for the first time in this thesis. The larvae of all ten species and the eggs of seven, have been correlated with the adults and are described. Two crocin genera, Concroce and Thysanocroce, have larvae with short prothoraxes, whilst those in Laurhervasia and Tjederia are elongated. Larvae of the first two genera live in plant detritus under rocks and in crevices whereas larvae of the latter two genera inhabit small dusty caves. These findings on the Myrmeleontidae and Nemopteridae are discussed in the context of general systematic theory, phylogeny and zoogeography.
- Full Text:
- Date Issued: 1979
- Authors: Mansell, Mervyn W
- Date: 1979
- Subjects: Ant lions -- Africa, Southern
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5594 , http://hdl.handle.net/10962/d1002044
- Description: The biology of southern African Myrmeleontidae and Nemopteridae (Neuroptera, Myrmeleontoidea) was studied with special emphasis on the nemopterid subfamily Crocinae. The superfamily Myrmeleontoidea is considered to be a monophyletic group derived from ancestors similar to the family Nymphidae. The Myrmeleontidae and Nemopteridae are the most highly evolved families, and the Nemopteridae have a sistergroup relationship with the other four myrmeleontoid families. Within the Nemopteridae, the Crocinae are considered more advanced than the subfamily Nemopterinae. An account of previous work on the two families is presented: literature relating to the Myrmeleontidae is catalogued in appendix 2 and publications dealing with the Nemopteridae are surveyed in the text . Biological and morphological information derived from the immature stages as well as the adults was used in the systematic study of the two families. The geographical distribution and phylogeny of the Myrmeleontoidea is discussed with particular reference to the Myrmeleontidae and Nemopteridae. The Myrmeleontidae have a world wide distribution whilst the Nemopteridae are more restricted, being limited to the arid and semi-arid regions of the world. It is concluded that the two families originated on Gondwanaland, and their present distribution is explained on the basis of evidence provided by plate tectonics. In southern Africa, the Myrmeleontidae show two distributional trends: there is a distinct western fauna including many endemics and an eastern fauna which comprises taxa with a wide distribution in central and east Africa, extending their ranges into the eastern parts of the subregion. The Nemopteridae occur predominantly on the western side of the subcontinent and over 90% of the species are endemic to southern Africa. A systematic revision of the southern African Crocinae is presented and summarized in a set of illustrated keys to the adults and larvae. There are now ten known crocin species in four genera from the subregion, four species being described for the first time in this thesis. The larvae of all ten species and the eggs of seven, have been correlated with the adults and are described. Two crocin genera, Concroce and Thysanocroce, have larvae with short prothoraxes, whilst those in Laurhervasia and Tjederia are elongated. Larvae of the first two genera live in plant detritus under rocks and in crevices whereas larvae of the latter two genera inhabit small dusty caves. These findings on the Myrmeleontidae and Nemopteridae are discussed in the context of general systematic theory, phylogeny and zoogeography.
- Full Text:
- Date Issued: 1979
Assessing the role of social transfers in curbing household food insecurity in Harare rural district, Zimbabwe
- Nyabvudzi, Tatenda Gaudencia
- Authors: Nyabvudzi, Tatenda Gaudencia
- Date: 2015
- Subjects: Poverty -- Zimbabwe Food security -- Zimbabwe Households -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/12205 , vital:39197
- Description: Purpose – Empirical work on the career development processes of vulnerable groups such as refugees is beginning to receive currency within the academic literature. However, little is known about the intersection of factors such as gender and structural constraints on such processes especially within developing countries such as South Africa. The purpose of this study was to explore the career development processes of women refugees in South Africa. Design/methodology/ approach – A qualitative research approach through narrative inquiry was used. Snowball sampling was employed to select the 20 women refugees who took part in this research. The study location was the city of Port Elizabeth located in the Eastern Cape Province. The three levels of meaning-making incorporated in previous narrative research was utilised to analyse the data. Findings Results show that women refugees are more concerned with a short-term desire to survive and acquire basic commodities than a long-term focus to advance and develop their careers. This is mainly compounded by constraints personal to the individual and those in the environment. Finally, the results illustrate that career development processes of women refugees are affected by the inextricably intertwined factors associated with their gender, immigration status as well as person-environmental factors. Practical implications – The research suggests strategies that policy makers in South Africa and other developing nations that are hosting refugees can use to assist women not just their career development but also their lived experiences. Originality/value – This study extends and advances literature on the career development issues of vulnerable groups such as women refugees especially in developing nations such as South Africa.
- Full Text:
- Date Issued: 2015
- Authors: Nyabvudzi, Tatenda Gaudencia
- Date: 2015
- Subjects: Poverty -- Zimbabwe Food security -- Zimbabwe Households -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/12205 , vital:39197
- Description: Purpose – Empirical work on the career development processes of vulnerable groups such as refugees is beginning to receive currency within the academic literature. However, little is known about the intersection of factors such as gender and structural constraints on such processes especially within developing countries such as South Africa. The purpose of this study was to explore the career development processes of women refugees in South Africa. Design/methodology/ approach – A qualitative research approach through narrative inquiry was used. Snowball sampling was employed to select the 20 women refugees who took part in this research. The study location was the city of Port Elizabeth located in the Eastern Cape Province. The three levels of meaning-making incorporated in previous narrative research was utilised to analyse the data. Findings Results show that women refugees are more concerned with a short-term desire to survive and acquire basic commodities than a long-term focus to advance and develop their careers. This is mainly compounded by constraints personal to the individual and those in the environment. Finally, the results illustrate that career development processes of women refugees are affected by the inextricably intertwined factors associated with their gender, immigration status as well as person-environmental factors. Practical implications – The research suggests strategies that policy makers in South Africa and other developing nations that are hosting refugees can use to assist women not just their career development but also their lived experiences. Originality/value – This study extends and advances literature on the career development issues of vulnerable groups such as women refugees especially in developing nations such as South Africa.
- Full Text:
- Date Issued: 2015
Development of integrated biological processing for the biodesalination of sulphate- and metal-rich wastewaters
- Authors: Boshoff, Genevieve Ann
- Date: 1999
- Subjects: Sewage -- Purification -- Biological treatment Sulfates Mineral industries -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3899 , http://hdl.handle.net/10962/d1003958
- Description: The substantial pollution threat to the South African environment from acid mine drainage (AMD) effluents has been well documented. Due to the juvenile nature of acidity in these flows, any remediation strategies implemented will need to function effectively and at low cost for long periods of time. The widespread use of sulphate reducing biological systems for the treatment of such effluents, and in particular large volume flows, has been limited. The supply of inexpensive electron donor and carbon sources, as well as appropriate reactor designs capable of handling large volume flows, have been identified as among the principal factors limiting development of this technology. The broad aim of the research programme reported here was to undertake an evaluation of the feasibility of an algal-bacterial integrated ponding system for the treatment of AMD, and the waste stabilisation pond (WSP) as an appropriate reactor design for this application. The study attempted to demonstrate the feasibility of individual unit operations in a proposed process train using complex organic carbon serving as the electron donor source for the sulphate reducing bacteria (SRB). Studies were undertaken as laboratory and pilot-scale investigations. Tannery effluent was shown to be a functional carbon source for biological sulphate reduction, with effective removal of sulphate and organics being recorded. In turn, the use of biological sulphate reduction for the treatment of tannery effluent was demonstrated. Algal biomass was shown in laboratory studies to function as an effective carbon source for biological sulphate reduction. It is known that micro-algae produce large quantities of photosynthate which is released to the growth medium under conditions of physiological stress. The potential for the use of photosynthate production in high rate algal ponding systems and its manipulation and use as a sustainable carbon source for sulphate reduction was investigated. Growth of a mixed culture of Dunaliella under conditions of light, temperature and salinity stress demonstrated production of large quantities of organic carbon. However, growth was inhibited at high temperatures. An elevation of salinity levels led to a decrease in growth of Dunaliella, but to increased organic carbon production. Spirulina spp., on the other hand, grew well at higher temperatures but showed the highest organic carbon production, and release to the medium, under low light conditions. These results led to a proposed process for the integration of algal ponding into an integrated system for the treatment of AMD. The algal biomass may be fed into the anaerobic digester as a carbon source, or it may be passed into a High Rate Algal Pond (HRAP) where it is stressed to enhance the organic carbon content. This can then be fed into the anaerobic digester as a carbon source. The impact of high levels of sulphide in the water feeding to the algal growth compartment was investigated. Spirulina spp. isolated from a tannery waste stabilisation pond was shown to be a sulphidophilic strain of cyanobacterium, capable of being adapted to high concentrations of sulphide. Dunaliella salina on the other hand was less tolerant. These results demonstrated the practical use of algal biomass providing an oxygen-rich cap for odour control on the surface of the facultative pond as well for the secondary treatment of sulphide-rich overflow to the High Rate Algal Pond. The ability of micro-algae to elevate the pH of their surrounding environment was evaluated as a functional precipitant and neutralisation reagent for acidic metal containing wastewater. Spirulina spp. was shown to perform effectively. D. salina was less functional in this environment. Anacystis spp. was effective in elevating the pH of a defined medium as well as a zinc-rich effluent. These results indicated the practicality of a neutralising function for algal ponds in the treatment of AMD. Metal removal in the system was found to be a combined function of sulphide precipitation, removal by binding to micro-algal biomass and extracellular polymeric substances. The feasibility of waste stabilisation ponding technology use for the treatment of large volume AMD effluents was provisionally demonstrated. It was shown that complex carbon sources would be used as efficient electron donors for sulphate reduction. The integration of algal ponding into the system provides for the generation of a sustainable carbon source, odour control with the recycling of oxygen-rich water onto the top of the facultative pond, secondary treatment of the anaerobic digester overflow, and the neutralisation of the incoming acidic effluents and removal of heavy metals. Integration of the individual unit operations, the feasibility of which has been provisionally demonstrated in this study, into a continuous process train is being investigated in follow-upstudies.
- Full Text:
- Date Issued: 1999
- Authors: Boshoff, Genevieve Ann
- Date: 1999
- Subjects: Sewage -- Purification -- Biological treatment Sulfates Mineral industries -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3899 , http://hdl.handle.net/10962/d1003958
- Description: The substantial pollution threat to the South African environment from acid mine drainage (AMD) effluents has been well documented. Due to the juvenile nature of acidity in these flows, any remediation strategies implemented will need to function effectively and at low cost for long periods of time. The widespread use of sulphate reducing biological systems for the treatment of such effluents, and in particular large volume flows, has been limited. The supply of inexpensive electron donor and carbon sources, as well as appropriate reactor designs capable of handling large volume flows, have been identified as among the principal factors limiting development of this technology. The broad aim of the research programme reported here was to undertake an evaluation of the feasibility of an algal-bacterial integrated ponding system for the treatment of AMD, and the waste stabilisation pond (WSP) as an appropriate reactor design for this application. The study attempted to demonstrate the feasibility of individual unit operations in a proposed process train using complex organic carbon serving as the electron donor source for the sulphate reducing bacteria (SRB). Studies were undertaken as laboratory and pilot-scale investigations. Tannery effluent was shown to be a functional carbon source for biological sulphate reduction, with effective removal of sulphate and organics being recorded. In turn, the use of biological sulphate reduction for the treatment of tannery effluent was demonstrated. Algal biomass was shown in laboratory studies to function as an effective carbon source for biological sulphate reduction. It is known that micro-algae produce large quantities of photosynthate which is released to the growth medium under conditions of physiological stress. The potential for the use of photosynthate production in high rate algal ponding systems and its manipulation and use as a sustainable carbon source for sulphate reduction was investigated. Growth of a mixed culture of Dunaliella under conditions of light, temperature and salinity stress demonstrated production of large quantities of organic carbon. However, growth was inhibited at high temperatures. An elevation of salinity levels led to a decrease in growth of Dunaliella, but to increased organic carbon production. Spirulina spp., on the other hand, grew well at higher temperatures but showed the highest organic carbon production, and release to the medium, under low light conditions. These results led to a proposed process for the integration of algal ponding into an integrated system for the treatment of AMD. The algal biomass may be fed into the anaerobic digester as a carbon source, or it may be passed into a High Rate Algal Pond (HRAP) where it is stressed to enhance the organic carbon content. This can then be fed into the anaerobic digester as a carbon source. The impact of high levels of sulphide in the water feeding to the algal growth compartment was investigated. Spirulina spp. isolated from a tannery waste stabilisation pond was shown to be a sulphidophilic strain of cyanobacterium, capable of being adapted to high concentrations of sulphide. Dunaliella salina on the other hand was less tolerant. These results demonstrated the practical use of algal biomass providing an oxygen-rich cap for odour control on the surface of the facultative pond as well for the secondary treatment of sulphide-rich overflow to the High Rate Algal Pond. The ability of micro-algae to elevate the pH of their surrounding environment was evaluated as a functional precipitant and neutralisation reagent for acidic metal containing wastewater. Spirulina spp. was shown to perform effectively. D. salina was less functional in this environment. Anacystis spp. was effective in elevating the pH of a defined medium as well as a zinc-rich effluent. These results indicated the practicality of a neutralising function for algal ponds in the treatment of AMD. Metal removal in the system was found to be a combined function of sulphide precipitation, removal by binding to micro-algal biomass and extracellular polymeric substances. The feasibility of waste stabilisation ponding technology use for the treatment of large volume AMD effluents was provisionally demonstrated. It was shown that complex carbon sources would be used as efficient electron donors for sulphate reduction. The integration of algal ponding into the system provides for the generation of a sustainable carbon source, odour control with the recycling of oxygen-rich water onto the top of the facultative pond, secondary treatment of the anaerobic digester overflow, and the neutralisation of the incoming acidic effluents and removal of heavy metals. Integration of the individual unit operations, the feasibility of which has been provisionally demonstrated in this study, into a continuous process train is being investigated in follow-upstudies.
- Full Text:
- Date Issued: 1999
An investigation into the use of guidelines and patterns in the interaction design process
- Authors: Cowley, Niel Lester Orr
- Date: 2009
- Subjects: Human-computer interaction , Web sites -- Design , User interfaces (Computer systems) -- Design
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10466 , http://hdl.handle.net/10948/1062 , Human-computer interaction , Web sites -- Design , User interfaces (Computer systems) -- Design
- Description: Design guidelines are used in interaction design (IxD) for physical design and for evaluating the usability of designs and interactive products. Guidelines are widely used for physical design and evaluation, but have a number of problems. IxD patterns have been proposed as an alternative to guidelines, as they are claimed to have several advantages over guidelines. A small number of empirical studies provide evidence that patterns are beneficial when used in IxD. Additional research on the usefulness of IxD patterns is required. The primary research question investigated in this thesis was thus: How useful are IxD patterns as physical design and evaluation aids in IxD, as compared to design guidelines? The role of guidelines and patterns as design and evaluation aids in IxD was investigated and a comparison of guidelines and patterns, based on a set of guideline and pattern properties, was conducted. The concept of pattern and guideline usefulness was explored and a research agenda for guidelines and patterns was identified, together with a set of research questions for an empirical study. The empirical study of the use of patterns for evaluation, redesign and new design, as compared to guidelines, was conducted at the Nelson Mandela Metropolitan University in 2004. The participants were a purposive sample of post-graduate Computing students, who were regarded as novice interaction designers. Two equivalent groups were formed, one that used patterns and one that used guidelines. Patterns were found to be as useful as guidelines when used as evaluation aids. Guidelines and patterns were identified as effective tools for identifying and explaining usability issues and design features. Best-effort matched sets of guidelines and patterns produced substantially different result sets when used to identify issues and features, with fairly low overlap. A substantial evaluator effect was observed for the use of guidelines and patterns for evaluation, and the results obtained were similar to those obtained by Molich et al. in their Comparative Usability Evaluation (CUE) studies. There was no statistically significant difference between the effectiveness of guidelines and patterns for evaluation. There was also no statistically significant difference between the perceived efficiency, effectiveness and satisfaction in use of guidelines and patterns for evaluation. Guidelines and patterns were found to be used in similar ways for evaluation. Patterns were found to be more effective than guidelines for redesign. Patterns were found to be as useful as guidelines when used for new design. There was no statistically significant difference between the effectiveness of guidelines and patterns for new design. There was also no statistically significant difference between the perceived efficiency, effectiveness and satisfaction in use of guidelines and patterns for redesign and new design. Guidelines and patterns were found to be used in similar ways for design. There was no statistically significant difference between the perceived usefulness of the format, content, ease of learning, and usefulness as personal and shared design languages, of guidelines and patterns. Both participant groups were equally agreeable to using guidelines and patterns in the future. The perceived usefulness of pattern collections was found to depend on the usability of the collection interface and the content quality of the patterns. The results of the empirical study thus provided empirical evidence that patterns were as useful as guidelines for evaluation and new design, and were perceived as positively as guidelines were. Patterns were found to be superior to guidelines for redesign. Patterns can therefore be used with a measure of confidence as early stage design aids for physical design and evaluation in the future. In addition to these findings, a number of opportunities for further research were identified.
- Full Text:
- Date Issued: 2009
- Authors: Cowley, Niel Lester Orr
- Date: 2009
- Subjects: Human-computer interaction , Web sites -- Design , User interfaces (Computer systems) -- Design
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10466 , http://hdl.handle.net/10948/1062 , Human-computer interaction , Web sites -- Design , User interfaces (Computer systems) -- Design
- Description: Design guidelines are used in interaction design (IxD) for physical design and for evaluating the usability of designs and interactive products. Guidelines are widely used for physical design and evaluation, but have a number of problems. IxD patterns have been proposed as an alternative to guidelines, as they are claimed to have several advantages over guidelines. A small number of empirical studies provide evidence that patterns are beneficial when used in IxD. Additional research on the usefulness of IxD patterns is required. The primary research question investigated in this thesis was thus: How useful are IxD patterns as physical design and evaluation aids in IxD, as compared to design guidelines? The role of guidelines and patterns as design and evaluation aids in IxD was investigated and a comparison of guidelines and patterns, based on a set of guideline and pattern properties, was conducted. The concept of pattern and guideline usefulness was explored and a research agenda for guidelines and patterns was identified, together with a set of research questions for an empirical study. The empirical study of the use of patterns for evaluation, redesign and new design, as compared to guidelines, was conducted at the Nelson Mandela Metropolitan University in 2004. The participants were a purposive sample of post-graduate Computing students, who were regarded as novice interaction designers. Two equivalent groups were formed, one that used patterns and one that used guidelines. Patterns were found to be as useful as guidelines when used as evaluation aids. Guidelines and patterns were identified as effective tools for identifying and explaining usability issues and design features. Best-effort matched sets of guidelines and patterns produced substantially different result sets when used to identify issues and features, with fairly low overlap. A substantial evaluator effect was observed for the use of guidelines and patterns for evaluation, and the results obtained were similar to those obtained by Molich et al. in their Comparative Usability Evaluation (CUE) studies. There was no statistically significant difference between the effectiveness of guidelines and patterns for evaluation. There was also no statistically significant difference between the perceived efficiency, effectiveness and satisfaction in use of guidelines and patterns for evaluation. Guidelines and patterns were found to be used in similar ways for evaluation. Patterns were found to be more effective than guidelines for redesign. Patterns were found to be as useful as guidelines when used for new design. There was no statistically significant difference between the effectiveness of guidelines and patterns for new design. There was also no statistically significant difference between the perceived efficiency, effectiveness and satisfaction in use of guidelines and patterns for redesign and new design. Guidelines and patterns were found to be used in similar ways for design. There was no statistically significant difference between the perceived usefulness of the format, content, ease of learning, and usefulness as personal and shared design languages, of guidelines and patterns. Both participant groups were equally agreeable to using guidelines and patterns in the future. The perceived usefulness of pattern collections was found to depend on the usability of the collection interface and the content quality of the patterns. The results of the empirical study thus provided empirical evidence that patterns were as useful as guidelines for evaluation and new design, and were perceived as positively as guidelines were. Patterns were found to be superior to guidelines for redesign. Patterns can therefore be used with a measure of confidence as early stage design aids for physical design and evaluation in the future. In addition to these findings, a number of opportunities for further research were identified.
- Full Text:
- Date Issued: 2009
Transcription, edition, translation and critical analysis of biographical poems contributed by S E K Mqhayi to early IsiXhosa newspapers
- Authors: Mazwi, Ntombomzi R
- Date: 2017
- Subjects: Mqhayi, S E K -- Criticism and interpretation , Mqhayi, S E K -- Translations , Xhosa language -- Transcription , Xhosa poetry -- History and criticism , Xhosa poetry -- Translations
- Language: English , Xhosa
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/18570 , vital:22356
- Description: During the nineteenth century secular creative literature produced by missionaries and publishers was designed for the educational market and for school children and there was nothing for adults. Works of isiXhosa literature was controlled in content and freely edited by the missionaries to satisfy the demands of educational syllabuses. As a result, students at universities, scholars of literature and academics in higher education are lacking primary documents on this literature and therefore are forced to study the limited and unavailable literature books. This thesis concentrates on the work of a particular isiXhosa writer, namely that of S.E.K. Mqhayi. The earlier writers like S.E.K. Mqhayi, J.J.R. Jolobe, G.B. Sinxo and others made their mark in South African literature and culture. Their works were published in journals and newspapers in isiXhosa by the missionaries. This means isiXhosa literature can be found in abundance in the earlier newspapers. What needs to be addressed is how the South African community and literature scholars mentioned above could have access to that work. Mqhayi is well known as the father of the isiXhosa language because of his substantial literary and linguistic contribution to the development of the language. As already mentioned he made his contribution through written work which was published in various newspapers of his time and unfortunately most people are unable to access this material, hence the focus of this thesis. The vast majority of his journalism remains as yet uncollected. However, scholars like Opland (1983) and Saule (1989) made some effort to bring this information to the public through their extensive research. S.E.K. Mqhayi’s popular poems have been published and analyzed over the last century and more recently (Qangule 1979; Kuse 1979; Opland 1983; Saule 1989 & 1996; Ntuli & Swanepoel 1993 and Opland 2009). However, in terms of quantity and value, these are negligible compared to what Mqhayi has published. There are still numerous of Mqhayi’s poems that would add value to the study and history of isiXhosa literature. The main aim of this research is to carry on from where these scholars left off and to bring to the fore the legacy Mqhayi left to the South African people. Hence, thirty (30) poems on people by S.E.K. Mqhayi have been transcribed from the old newspapers, re- typed, translated into English and analysed. These poems are largely published in newspapers but have never been subsequently republished, and hence they are almost completely unknown. The thirty (30) poems have been selected with the assistance of Professor Jeff Opland, a retired Professor from the University of London’s School of Oriental and African Studies (SOAS). The poems are from his Opland Collection of Xhosa Literature housed in Godalming, United Kingdom. They are presented in the manner in which they appeared originally, that is, in terms of isiXhosa orthography during the times of Mqhayi’s writing (Diplomatic Presentation). The data is analysed and discussed in relation to how Mqhayi’s biographical poems can give insight not only to Mqhayi’s subjects of praise, but into how he uses historical, political and sociocultural contexts in the praises of his subjects, meaning that the discussion revolves around the practice of the Historical-Biographical Criticism. The poems are translated into English to allow for this literature not only to be disseminated among isiXhosa speakers, but also to speakers of other languages who understand English. The translation method chosen is the one believed to produce the originality of the source text and sameness of meaning in the target text which is regarded as equivalence. This thesis therefore is an investigation into 30 poems selected from biographical poems written by S.E.K. Mqhayi in newspapers during the period 1899-1944. In essence this thesis presents an in-depth analysis of Mqhayi’s poems against the backdrop of oral literary theory as expounded by theorists who have grappled with the orality-literacy debate, a debate which directly informs Mqhayi’s poetry as he was the first oral poet to transition between orality and literacy. , Uncwadi oluveliswe kwishumi elinesithoba lamakhulu eminyaka ziimishinari nabapapashi lwalwenzelwe izifundiswa kunye nabantwana besikolo kwaye akukho msebenzi mninzi ofumanekayo owawenzelwe abantu basekuhlaleni. Umsebenzi omninzi wokubhaliweyo kuncwadi lwesiXhosa wawulawulwa, uhlelwa kwaye ulungiselelwa uqingqo lwezifundo. Oko ke kuye kwabangela ukuba abafundi abakumaziko emfundo ephakamileyo, iimfundi zoncwadi kunye nabahlohli zingabinawo amaxwebhu okwenene oncwadi lwesiXhosa, kwaye loo nto yenza ukuba kufundwe kwaye kwenziwe uphando ngeencwadi ezimbalwa. Olu phando ke ngoko luza kuqwalasela lugxininise kumsebenzi wombhali wesiXhosa onguS.E.K. Mqhayi. Ababhali bangaphambili abafana noo-S.E.K. Mqhayi, J.J.R. Jolobe, G.B. Sinxo nabanye bashiya ifuthe elikhulu kuncwadi nenkcubeko yoMzantsi Afrika. Imisebenzi yabo yayipapashwe ziimishinari ngesiXhosa kuluhlu lwemibhalo namaphephandaba. Oko ke kuthetha ukuthi le misebenzi yesiXhosa iyafumaneka kumaphepha-ndaba angaphambili. Okufuneka kulungisiwe yindlela abemi boMzantsi Afrika kunye nezi mfundi zoncwadi zikhankanywe ngentla zingathi ziwufumane lo msebenzi waba babhali bangaphambili. UMqhayi waziwa ngokuba yinkcuba- buchopho yolwimi lwesiXhosa kwaye udlale indima enkulu kakhulu ekuphuhliseni ulwimi lwesiXhosa. Njengokuba sele ikhankanyiwe ngentla, umsebenzi wakhe upapashwe kumaphephandaba awohlukeneyo wela xesha wayesaphila kwaye kungelishwa ke ukuba abantu abaninzi abakwazi ukuwufumana loo msebenzi. Eminye yemisebenzi yakhe emininzi ke kodwa ayiqokelelwanga. Iingcali ezifana noo-Opland (1983) noSaule (1989) zaye zenza uphando olukhulu zizama ukuzisa olu lwazi eluntwini, kodwa oko akwanelanga. Kwiminyaka edlulileyo imibongo edumileyo ka-S.E.K. Mqhayi sele yapapashwa (Qangule, 1979; Kuse, 1979; Opland, 1983 & 2009; Saule, 1989 & 1996; Ntuli & Swanepoel, 1993). Nangona kunjalo ke isekhona eminye imibongo kaMqhayi engekaveli nenokuthi ibe nenxaxheba kakhulu ekufundeni nasekufundiseni uncwadi lwesiXhosa. Olu phando ke kukuqhubeka apho aba babhali bakhankanyiweyo bayeke khona ukuzisa phambili umsebenzi nelifa elashiywa nguMqhayi kubemi baseMzantsi Afrika. Kungoko ke imibongo engabantu engama-30 kaMqhayi iza kuthi ikhutshelwe isuka kumaphephandaba akudala, iguqulelwe esiNgesini ze ihlahlelwe. Uninzi lwale mibongo ipapashwe kumaphephandaba akudala kwaye zange iphinde ipapashwe kwenye indawo, kungoko ke ingaziwa kakhulu. Ukukhethwa kwale mibongo ingama-30 kuncediswe nguNjingalwazi uJeff Opland, uNjingalwazi odla umhlala-phantsi weYunivesithi yase-London kwiSikolo seZifundo ngezaseAfrika naseMpumalanga (SOAS). Le mibongo isuka kuluhlu lwakhe athe waluqokelela nolubizwa ngokuba yi-Opland Collection of Xhosa Literature oluse- Godalming, e-United Kingdom. Indlela le mibongo eza kuthi ibhalwe ngayo yileyo uMqhayi wayeyibhale ngayo ngexesha lakhe. Le mibongo ihleliwe kwaye oko kubhaliweyo malunga nayo kuquka indlela apho imibongo kaMqhayi ngobomi babantu kuthi kubonise indlela abonga nabonisa ngayo izinto zoPolitiko, zakudala nezasekuhlaleni ezazisenzeka ngela xesha. Indlela ethi konke oku kuthi kuvele kule mibongo kaMqhayi kwaye kuya kuthi kuvezwe kolu phando. Ukuguqulelwa kwale mibongo esiNgesini kuya kuthi kuncede ukuba nabo bangasithethiyo isiXhosa bakwazi ukufumana le mibongo. Indlela esetyenzisiweyo yoguqulo-lwimi yale mibongo yileyo ivumela ukuba umbhalo uguqulelwe ngokufanayo nombhalo-ntsusa kwaye intsingiselo kumbhalo ekuguqulelwa kuwo ingatshintshi. Lo misebenzi ke ngoko uluphando lwemibongo engabantu ekhethiweyo engama30 ebhalwe nguSEK Mqhayi kumaphephandaba kwimiminyaka u1899 - 1944. Umongo wolu phando kukwenza uhlalutyo - nzulu lwemibongo kaMqhayi eyaleka kuphando - lwazi osele lwenziwe njengoko lucaciswa ziingcali ezithe zazamana nengxoxo yoncwadi lomlomo, ngxoxo leyo ethe yachaphazela ngokumandla umongo wezibongo zikaMqhayi njengembongi yokuqala ukuwela ukusuka kuncwadi lomlomo ukuya kuncwadi olubhaliweyo.
- Full Text:
- Date Issued: 2017
- Authors: Mazwi, Ntombomzi R
- Date: 2017
- Subjects: Mqhayi, S E K -- Criticism and interpretation , Mqhayi, S E K -- Translations , Xhosa language -- Transcription , Xhosa poetry -- History and criticism , Xhosa poetry -- Translations
- Language: English , Xhosa
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/18570 , vital:22356
- Description: During the nineteenth century secular creative literature produced by missionaries and publishers was designed for the educational market and for school children and there was nothing for adults. Works of isiXhosa literature was controlled in content and freely edited by the missionaries to satisfy the demands of educational syllabuses. As a result, students at universities, scholars of literature and academics in higher education are lacking primary documents on this literature and therefore are forced to study the limited and unavailable literature books. This thesis concentrates on the work of a particular isiXhosa writer, namely that of S.E.K. Mqhayi. The earlier writers like S.E.K. Mqhayi, J.J.R. Jolobe, G.B. Sinxo and others made their mark in South African literature and culture. Their works were published in journals and newspapers in isiXhosa by the missionaries. This means isiXhosa literature can be found in abundance in the earlier newspapers. What needs to be addressed is how the South African community and literature scholars mentioned above could have access to that work. Mqhayi is well known as the father of the isiXhosa language because of his substantial literary and linguistic contribution to the development of the language. As already mentioned he made his contribution through written work which was published in various newspapers of his time and unfortunately most people are unable to access this material, hence the focus of this thesis. The vast majority of his journalism remains as yet uncollected. However, scholars like Opland (1983) and Saule (1989) made some effort to bring this information to the public through their extensive research. S.E.K. Mqhayi’s popular poems have been published and analyzed over the last century and more recently (Qangule 1979; Kuse 1979; Opland 1983; Saule 1989 & 1996; Ntuli & Swanepoel 1993 and Opland 2009). However, in terms of quantity and value, these are negligible compared to what Mqhayi has published. There are still numerous of Mqhayi’s poems that would add value to the study and history of isiXhosa literature. The main aim of this research is to carry on from where these scholars left off and to bring to the fore the legacy Mqhayi left to the South African people. Hence, thirty (30) poems on people by S.E.K. Mqhayi have been transcribed from the old newspapers, re- typed, translated into English and analysed. These poems are largely published in newspapers but have never been subsequently republished, and hence they are almost completely unknown. The thirty (30) poems have been selected with the assistance of Professor Jeff Opland, a retired Professor from the University of London’s School of Oriental and African Studies (SOAS). The poems are from his Opland Collection of Xhosa Literature housed in Godalming, United Kingdom. They are presented in the manner in which they appeared originally, that is, in terms of isiXhosa orthography during the times of Mqhayi’s writing (Diplomatic Presentation). The data is analysed and discussed in relation to how Mqhayi’s biographical poems can give insight not only to Mqhayi’s subjects of praise, but into how he uses historical, political and sociocultural contexts in the praises of his subjects, meaning that the discussion revolves around the practice of the Historical-Biographical Criticism. The poems are translated into English to allow for this literature not only to be disseminated among isiXhosa speakers, but also to speakers of other languages who understand English. The translation method chosen is the one believed to produce the originality of the source text and sameness of meaning in the target text which is regarded as equivalence. This thesis therefore is an investigation into 30 poems selected from biographical poems written by S.E.K. Mqhayi in newspapers during the period 1899-1944. In essence this thesis presents an in-depth analysis of Mqhayi’s poems against the backdrop of oral literary theory as expounded by theorists who have grappled with the orality-literacy debate, a debate which directly informs Mqhayi’s poetry as he was the first oral poet to transition between orality and literacy. , Uncwadi oluveliswe kwishumi elinesithoba lamakhulu eminyaka ziimishinari nabapapashi lwalwenzelwe izifundiswa kunye nabantwana besikolo kwaye akukho msebenzi mninzi ofumanekayo owawenzelwe abantu basekuhlaleni. Umsebenzi omninzi wokubhaliweyo kuncwadi lwesiXhosa wawulawulwa, uhlelwa kwaye ulungiselelwa uqingqo lwezifundo. Oko ke kuye kwabangela ukuba abafundi abakumaziko emfundo ephakamileyo, iimfundi zoncwadi kunye nabahlohli zingabinawo amaxwebhu okwenene oncwadi lwesiXhosa, kwaye loo nto yenza ukuba kufundwe kwaye kwenziwe uphando ngeencwadi ezimbalwa. Olu phando ke ngoko luza kuqwalasela lugxininise kumsebenzi wombhali wesiXhosa onguS.E.K. Mqhayi. Ababhali bangaphambili abafana noo-S.E.K. Mqhayi, J.J.R. Jolobe, G.B. Sinxo nabanye bashiya ifuthe elikhulu kuncwadi nenkcubeko yoMzantsi Afrika. Imisebenzi yabo yayipapashwe ziimishinari ngesiXhosa kuluhlu lwemibhalo namaphephandaba. Oko ke kuthetha ukuthi le misebenzi yesiXhosa iyafumaneka kumaphepha-ndaba angaphambili. Okufuneka kulungisiwe yindlela abemi boMzantsi Afrika kunye nezi mfundi zoncwadi zikhankanywe ngentla zingathi ziwufumane lo msebenzi waba babhali bangaphambili. UMqhayi waziwa ngokuba yinkcuba- buchopho yolwimi lwesiXhosa kwaye udlale indima enkulu kakhulu ekuphuhliseni ulwimi lwesiXhosa. Njengokuba sele ikhankanyiwe ngentla, umsebenzi wakhe upapashwe kumaphephandaba awohlukeneyo wela xesha wayesaphila kwaye kungelishwa ke ukuba abantu abaninzi abakwazi ukuwufumana loo msebenzi. Eminye yemisebenzi yakhe emininzi ke kodwa ayiqokelelwanga. Iingcali ezifana noo-Opland (1983) noSaule (1989) zaye zenza uphando olukhulu zizama ukuzisa olu lwazi eluntwini, kodwa oko akwanelanga. Kwiminyaka edlulileyo imibongo edumileyo ka-S.E.K. Mqhayi sele yapapashwa (Qangule, 1979; Kuse, 1979; Opland, 1983 & 2009; Saule, 1989 & 1996; Ntuli & Swanepoel, 1993). Nangona kunjalo ke isekhona eminye imibongo kaMqhayi engekaveli nenokuthi ibe nenxaxheba kakhulu ekufundeni nasekufundiseni uncwadi lwesiXhosa. Olu phando ke kukuqhubeka apho aba babhali bakhankanyiweyo bayeke khona ukuzisa phambili umsebenzi nelifa elashiywa nguMqhayi kubemi baseMzantsi Afrika. Kungoko ke imibongo engabantu engama-30 kaMqhayi iza kuthi ikhutshelwe isuka kumaphephandaba akudala, iguqulelwe esiNgesini ze ihlahlelwe. Uninzi lwale mibongo ipapashwe kumaphephandaba akudala kwaye zange iphinde ipapashwe kwenye indawo, kungoko ke ingaziwa kakhulu. Ukukhethwa kwale mibongo ingama-30 kuncediswe nguNjingalwazi uJeff Opland, uNjingalwazi odla umhlala-phantsi weYunivesithi yase-London kwiSikolo seZifundo ngezaseAfrika naseMpumalanga (SOAS). Le mibongo isuka kuluhlu lwakhe athe waluqokelela nolubizwa ngokuba yi-Opland Collection of Xhosa Literature oluse- Godalming, e-United Kingdom. Indlela le mibongo eza kuthi ibhalwe ngayo yileyo uMqhayi wayeyibhale ngayo ngexesha lakhe. Le mibongo ihleliwe kwaye oko kubhaliweyo malunga nayo kuquka indlela apho imibongo kaMqhayi ngobomi babantu kuthi kubonise indlela abonga nabonisa ngayo izinto zoPolitiko, zakudala nezasekuhlaleni ezazisenzeka ngela xesha. Indlela ethi konke oku kuthi kuvele kule mibongo kaMqhayi kwaye kuya kuthi kuvezwe kolu phando. Ukuguqulelwa kwale mibongo esiNgesini kuya kuthi kuncede ukuba nabo bangasithethiyo isiXhosa bakwazi ukufumana le mibongo. Indlela esetyenzisiweyo yoguqulo-lwimi yale mibongo yileyo ivumela ukuba umbhalo uguqulelwe ngokufanayo nombhalo-ntsusa kwaye intsingiselo kumbhalo ekuguqulelwa kuwo ingatshintshi. Lo misebenzi ke ngoko uluphando lwemibongo engabantu ekhethiweyo engama30 ebhalwe nguSEK Mqhayi kumaphephandaba kwimiminyaka u1899 - 1944. Umongo wolu phando kukwenza uhlalutyo - nzulu lwemibongo kaMqhayi eyaleka kuphando - lwazi osele lwenziwe njengoko lucaciswa ziingcali ezithe zazamana nengxoxo yoncwadi lomlomo, ngxoxo leyo ethe yachaphazela ngokumandla umongo wezibongo zikaMqhayi njengembongi yokuqala ukuwela ukusuka kuncwadi lomlomo ukuya kuncwadi olubhaliweyo.
- Full Text:
- Date Issued: 2017
The evolution of heteronomous host relationships in Aphelinidaa (Hymenoptera Chalcidoidea) with special reference to the biology of Coccophagus Bartletti Annecke and Insley
- Authors: Walter, Grenville Hugh
- Date: 1984
- Subjects: Hymenoptera
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5620 , http://hdl.handle.net/10962/d1003746
- Description: Résumé: Heteronomous host relationships are unique to parasitoids in about 8 aphelinid genera. Males have host relationships quite distinct from those of their females. Females of ALL species are primary endoparasitoids of homopterous hosts. Males, on the other hand, may be either primary ectoparasitoids of the same host species as their conspecific females, or they may be hyperparasitic upon parasitoids within Homoptera, and some are primary endoparasitoids of moth eggs. Species in these groups are termed DIPHAGOUS PARASITOIDS, HETERONOMOUS HYPERPARASITOIDS and HETEROTROPHIC PARASITOIDS, respectively. The selective advantages proposed to explain the evolution of these unusual host relationships are examined in this thesis. The biology of a diphagous parasitoid was examined in detail because diphagous parasitism is considered the most primitive of heteronomous host relationships. Diphagous parasitism is thought to have evolved during a period when ovipositing females continuously encountered large proportions of parasitised hosts. Larval competition may have generated the selection pressures that favoured male ectoparasitism. Ectoparasitoids are known to be superior in competition against other larvae, even older ones. A series of observations was carried out on the diphagous parasitoid, Coccophagus bartletti. Information was gathered on oviposition and host-feeding behaviour, daily activity patterns, and sex ratios in the laboratory and field. This enabled the design and interpretation of a series of observations on the responses of mated C. bartletti females to already-parasitised hosts. The results indicate that competition from other parasitoids probably played no role in the evolution of diphagous host relationships. Heteronomous hyperparasitoids, thought to have evolved from diphagous parasitoids, appear to be strong competitors because their males kill other parasitoids. However, an alternative hypothesis to the competition one, and based on the present study, is presented. Implications for the generally-held view, that competition is important in moulding species' characters, are discussed.
- Full Text:
- Date Issued: 1984
- Authors: Walter, Grenville Hugh
- Date: 1984
- Subjects: Hymenoptera
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5620 , http://hdl.handle.net/10962/d1003746
- Description: Résumé: Heteronomous host relationships are unique to parasitoids in about 8 aphelinid genera. Males have host relationships quite distinct from those of their females. Females of ALL species are primary endoparasitoids of homopterous hosts. Males, on the other hand, may be either primary ectoparasitoids of the same host species as their conspecific females, or they may be hyperparasitic upon parasitoids within Homoptera, and some are primary endoparasitoids of moth eggs. Species in these groups are termed DIPHAGOUS PARASITOIDS, HETERONOMOUS HYPERPARASITOIDS and HETEROTROPHIC PARASITOIDS, respectively. The selective advantages proposed to explain the evolution of these unusual host relationships are examined in this thesis. The biology of a diphagous parasitoid was examined in detail because diphagous parasitism is considered the most primitive of heteronomous host relationships. Diphagous parasitism is thought to have evolved during a period when ovipositing females continuously encountered large proportions of parasitised hosts. Larval competition may have generated the selection pressures that favoured male ectoparasitism. Ectoparasitoids are known to be superior in competition against other larvae, even older ones. A series of observations was carried out on the diphagous parasitoid, Coccophagus bartletti. Information was gathered on oviposition and host-feeding behaviour, daily activity patterns, and sex ratios in the laboratory and field. This enabled the design and interpretation of a series of observations on the responses of mated C. bartletti females to already-parasitised hosts. The results indicate that competition from other parasitoids probably played no role in the evolution of diphagous host relationships. Heteronomous hyperparasitoids, thought to have evolved from diphagous parasitoids, appear to be strong competitors because their males kill other parasitoids. However, an alternative hypothesis to the competition one, and based on the present study, is presented. Implications for the generally-held view, that competition is important in moulding species' characters, are discussed.
- Full Text:
- Date Issued: 1984
A century of IsiXhosa written poetry and the ideological contest in South Africa
- Authors: Mona, Godfrey Vulindlela
- Date: 2015
- Subjects: Xhosa poetry -- History and criticism , Protest poetry, Xhosa , Ideology and literature
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3651 , http://hdl.handle.net/10962/d1017892
- Description: The central argument of this inter-disciplinary study is that IsiXhosa written poetry of 1912 – 2012 is a terrain of the struggle between the contending dominant ideologies of Segregation, Apartheid and Charterism (post-Apartheid); and the subordinate/ subaltern ideologies of Africanism, Charterism (pre-democracy), Pan- Africanism, Black Consciousness Movement and other post Apartheid ideologies. The study highlights the mutual relationship between the text and the context by focussing on the ideological contest which manifests itself in both form and structure (i.e. aesthetic ideology) and the content (i.e. authorial ideology) of the poetry of different epochs between 1912 and 2012. The study is located within the framework of Antonio Gramsci’s theory of cultural construction. Gramsci postulates that ideology and culture play a significant role in the process of asserting hegemony. Important concepts that constitute Gramsci’s theory of praxis are: ideology, culture, hegemony, organic intellectuals and both ideological and repressive state apparatuses. The first chapter presents the problem, the objectives, the methodology, and the scope of the study. The second chapter presents Gramsci’s theory of cultural construction and the work of scholars who developed his theory further. The tool that is employed for analysis and interpretation of textual significations of IsiXhosa written poetry is the revolutionary aesthetics, which is proposed by Udenta. The third chapter analyses and interprets literature of the epoch of 1912-1934 and exposes the contest between Segregation and Africanism ideologies. The fourth chapter contextualises and analyses the literature of 1934 – 1948, the second phase of contestation between Segregation and Africanism. The fifth chapter deals with literature of the first and second halves of the Apartheid epoch (1948 - 1973). The Apartheid ideology contested with the Africanist ideology which transformed into the Charterism ideology in 1955. In 1960 Pan-Africanism ideology and in 1969 Black Consciousness Movement ideologies entered the contest. The sixth chapter examines literature of the period 1973 – 1994 which is the second phase of the Apartheid epoch that ends with the “glasnost” period of 1990 - 1994. The seventh chapter studies literature of the democracy period of 1994 – 2012. The eighth chapter is the summary and general conclusion. The illumination of the nexus between culture and ideology during the past century (1912 - 2012) will provide insights that will assist us in addressing the challenges we face during the democracy period, and in the development on Arts and Culture in general, and literature in particular
- Full Text:
- Date Issued: 2015
- Authors: Mona, Godfrey Vulindlela
- Date: 2015
- Subjects: Xhosa poetry -- History and criticism , Protest poetry, Xhosa , Ideology and literature
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3651 , http://hdl.handle.net/10962/d1017892
- Description: The central argument of this inter-disciplinary study is that IsiXhosa written poetry of 1912 – 2012 is a terrain of the struggle between the contending dominant ideologies of Segregation, Apartheid and Charterism (post-Apartheid); and the subordinate/ subaltern ideologies of Africanism, Charterism (pre-democracy), Pan- Africanism, Black Consciousness Movement and other post Apartheid ideologies. The study highlights the mutual relationship between the text and the context by focussing on the ideological contest which manifests itself in both form and structure (i.e. aesthetic ideology) and the content (i.e. authorial ideology) of the poetry of different epochs between 1912 and 2012. The study is located within the framework of Antonio Gramsci’s theory of cultural construction. Gramsci postulates that ideology and culture play a significant role in the process of asserting hegemony. Important concepts that constitute Gramsci’s theory of praxis are: ideology, culture, hegemony, organic intellectuals and both ideological and repressive state apparatuses. The first chapter presents the problem, the objectives, the methodology, and the scope of the study. The second chapter presents Gramsci’s theory of cultural construction and the work of scholars who developed his theory further. The tool that is employed for analysis and interpretation of textual significations of IsiXhosa written poetry is the revolutionary aesthetics, which is proposed by Udenta. The third chapter analyses and interprets literature of the epoch of 1912-1934 and exposes the contest between Segregation and Africanism ideologies. The fourth chapter contextualises and analyses the literature of 1934 – 1948, the second phase of contestation between Segregation and Africanism. The fifth chapter deals with literature of the first and second halves of the Apartheid epoch (1948 - 1973). The Apartheid ideology contested with the Africanist ideology which transformed into the Charterism ideology in 1955. In 1960 Pan-Africanism ideology and in 1969 Black Consciousness Movement ideologies entered the contest. The sixth chapter examines literature of the period 1973 – 1994 which is the second phase of the Apartheid epoch that ends with the “glasnost” period of 1990 - 1994. The seventh chapter studies literature of the democracy period of 1994 – 2012. The eighth chapter is the summary and general conclusion. The illumination of the nexus between culture and ideology during the past century (1912 - 2012) will provide insights that will assist us in addressing the challenges we face during the democracy period, and in the development on Arts and Culture in general, and literature in particular
- Full Text:
- Date Issued: 2015
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
Constraining simulation uncertainties in a hydrological model of the Congo River Basin including a combined modelling approach for channel-wetland exchanges
- Authors: Kabuya, Pierre Mulamba
- Date: 2021-04
- Subjects: Congo River Watershed , Watersheds -- Congo (Democratic Republic) , Hydrologic models , Rain and rainfall -- Mathematical models , Runoff -- Mathematical models , Wetland hydrology
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177997 , vital:42897 , 10.21504/10962/177997
- Description: Compared to other large river basins of the world, such as the Amazon, the Congo River Basin appears to be the most ungauged and less studied. This is partly because the basin lacks sufficient observational hydro-climatic monitoring stations and appropriate information on physiographic basin properties at a spatial scale deemed for hydrological applications, making it difficult to estimate water resources at the scale of sub-basins (Chapter 3). In the same time, the basin is facing the challenges related to rapid population growth, uncontrolled urbanisation as well as climate change. Adequate quantification of hydrological processes across different spatial and temporal scales in the basin, and the drivers of change, is essential for prediction and strategic planning to ensure sustainable management of water resources in the Congo River Basin. Hydrological models are particularly important to generate the required information. However, the shortness of the available streamflow records, lack of spatial representativeness of the available streamflow gauging stations and the lack of understanding of the processes in channel-wetland exchanges, are the main challenges that constrain the use of traditional approaches to models development. They also contribute to increased uncertainty in the estimation of water resources across the basin (Chapter 1 and 2). Given this ungauged nature of the Congo River Basin, it is important to resort to hydrological modelling approaches that can reasonably quantify and model the uncertainty associated with water resources estimation (Chapter 4) to make hydrological predictions reliable. This study explores appropriate methods for hydrological predictions and water resources assessment in ungauged catchments of the Congo River Basin. In this context, the core modelling framework combines the quantification of uncertainty in constraint indices, hydrological modelling and hydrodynamic modelling. The latter accounts for channel-wetland exchanges in sub-basins where wetlands exert considerable influence on downstream flow regimes at the monthly time scale. The constraint indices are the characteristics of a sub-basin’s long-term hydrological behaviour and may reflect the dynamics of the different components of the catchment water balance such as climate, water storage and different runoff processes. Currently, six constraint indices namely the mean monthly runoff volume (MMQ in m3 *106), mean monthly groundwater recharge depth (MMR in mm), the 10th, 50th and 90th percentiles of the flow duration curve expressed as a fraction of MMQ (Q10/MMQ, Q50/MMQ, Q90/MMQ) and the percentage of time that zero flows are expected (%Zero), are used in the modelling approach. These were judged to be the minimum number of key indices that can discriminate between different hydrological responses. The constraint indices in the framework help to determine an uncertainty range within which behavioural model parameters of the expected hydrological response can be identified. Predictive equations of the constraint indices across all climate and physiographic regions of the Congo Basin were based only on the aridity index because it was the most influential sub-basin attribute (Chapter 5) for which quantitative information was available. The degree of uncertainty in the constraint Q10/MMQ and Q50/MMQ indices is less than 41%, while it is somewhat higher for the mean monthly runoff (MMQ) and Q90/MMQ constraint indices. The established uncertainty ranges of the constraint indices were tested in some selected sub-basins of the Congo Basin, including the Lualaba (93 sub-basins), Sangha (24 sub-basins), Oubangui (19 sub-basins), Batéké plateaux (4 sub-basins), Kasai (4 sub-basins) and Inkisi (3 sub-basins). The results proved useful through the application of a 2-stage uncertainty approach of the PITMAN model. However, it comes out of this study that the application of the original constraint indices ranges (Chapter 5) generated satisfactory simulation results in some areas, while in others both small and large adjustments were required to fully capture some aspects of the observed hydrological responses (Chapter 6). Part of the reason is attributed to the availability and quality of streamflow data used to develop the constraint indices ranges (Chapter 5). The main issue identified in the modelling process was whether the changes made to the original constraints at headwater-gauged sub-basins can be applied to ungauged upstream sub-basins to match the observed flow at downstream gauging stations. Ideally, only gauged sub-basin’s constraints can be easily revised based on the observed flow. However, the refinement made to gauged sub-basins alone may fail to substantially affect the results if ungauged upstream sub-basins exert a major impact on defining downstream hydrological response. The majority of gauging stations used in this analysis are located downstream of many upstream ungauged sub-basins and therefore adjustments were required in ungauged sub-basins. These adjustments consist of shifting the full range of a constraint index either towards higher or lower values, depending on the degree to which the simulated uncertainty bounds depart from the observed flow. While this modelling approach seems effective in capturing many aspects of the hydrological responses with a reduced level of uncertainty compared to a previous study, it is recommended that the approach be extended to the remaining parts of the Congo Basin and assessed under current and future development conditions including environmental changes. A 2D hydrodynamic river-wetland model (LISFLOOD-FP) has been used to explicitly represent the inundation process exchanges between river channels and wetland systems. The hydrodynamic modelling outputs are used to calibrate the PITMAN wetland sub-model parameters. The five hydrodynamic models constructed for Ankoro, Kamalondo, Kundelungu, Mweru and Tshiangalele wetland systems have been partially validated using independent estimates of inundation extents available from Landsat imagery. Other sources of data such as remote sensing of water level altimetry, SAR images and wetland storage estimates may be used to improve the validation results. However, the important objective in this study was to make sure that flow volume exchanges between river channels and their adjacent floodplains were being simulated realistically. The wetland sub-model parameters are calibrated in a spreadsheet version of the PITMAN wetland routine to achieve visual correspondence between the LISFLOOD-FP and PITMAN wetland sub-model outputs (Storage volumes and channel outputs). The hysteretic patterns of the river-wetland processes were quantified using hysteresis indices and were associated with the spill and return flow parameters of the wetland sub-model and eventually with the wetland morphometric characteristics. One example is the scale parameter of the return flow function (AA), which shows a good relationship with the average surface slope of the wetland when the coefficient parameter (BB) of the same function is kept constant to a value of 1.25. The same parameter (AA) is a good indicator of the wetland emptying mechanism. A small AA indicates a wetland that slowly releases its flow, resulting in a highly delayed and attenuated hydrological response in downstream sub-basins. This understanding has a practical advantage for the estimation of the PITMAN wetland parameters in the many areas where it is not possible, or where the resources are not available, to run complex hydrodynamic models (Chapter 7). The inclusion of these LISFLOOD-FP informed wetland parameters in the basin-scale hydrological modelling results in acceptable simulations for the lower Lualaba drainage system. The small wetlands, like Ankoro and Tshiangalele, have a negligible impact on downstream flow regimes, whereas large wetlands, such as Kamalondo and Mweru, have very large impacts. In general, the testing of the original constraint indices in the region of wetlands and further downstream of the Lualaba drainage system has shown acceptable results. However, there remains an unresolved uncertainty issue related to the under and over-estimation of some aspects of the hydrological response at both Mulongo and Ankoro, two gauging stations in the immediate downstream of the Kamalondo wetland system. It is difficult to attribute this uncertainty to Kamalondo wetland parameters alone because many of the incremental sub-basins contributing to wetland inflows are ungauged. The issue at Mulongo is the under simulation of low flow, while the high flows at the Ankoro gauging station are over-simulated. However, the pattern of the calibrated constraint indices in this region (Chapter 8) shows that the under simulation of low flow at Mulongo cannot be attributed to incremental sub-basins (between Bukama, Kapolowe and Mulongo gauging stations), because their Q90/MMQ constraint indices are even slightly above the original constraint ranges, but maintain a spatial consistency with sub-basins of other regions. Similarly, sub-basins located between Mulongo, Luvua and Ankoro gauging stations have high flow indices slightly below the original constraint ranges and therefore they are unlikely to be responsible for the over simulation of high flow at the Ankoro gauging station. These facts highlight the need for a further understanding of the complex wetland system of Kamalondo. Short-term data collection and monitoring programme are required. Important tributaries that drain to this wetland need to be monitored by installing water level loggers and periodically collecting flow data and river bathymetry. This programme should lead to the development of rating curves of wetland input tributaries. This would partially solve the unresolved uncertainty issues at the Ankoro and Mulongo gauging stations. The integrated modelling approach offers many opportunities in the Congo Basin. The quantified and modelled uncertainty helps to identify regions with high uncertainty and allows for the identification of various data collection and management strategies that can potentially contribute to the uncertainty reduction. The quantified channel-wetland exchanges contribute to the improvement of the overall knowledge of water resources estimation within the regions where the effects of wetlands are evident even at the monthly time scale. In contrast, ignoring uncertainty in the estimates of water resources availability means that water resources planning and management decisions in the Congo Basin will continue to be based on inadequate information and unquantified uncertainty, thus increasing the risk associated with water resources decision making. , Thesis (PhD) -- Faculty of Science, Institute for Water Research, 2021
- Full Text:
- Date Issued: 2021-04
- Authors: Kabuya, Pierre Mulamba
- Date: 2021-04
- Subjects: Congo River Watershed , Watersheds -- Congo (Democratic Republic) , Hydrologic models , Rain and rainfall -- Mathematical models , Runoff -- Mathematical models , Wetland hydrology
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/177997 , vital:42897 , 10.21504/10962/177997
- Description: Compared to other large river basins of the world, such as the Amazon, the Congo River Basin appears to be the most ungauged and less studied. This is partly because the basin lacks sufficient observational hydro-climatic monitoring stations and appropriate information on physiographic basin properties at a spatial scale deemed for hydrological applications, making it difficult to estimate water resources at the scale of sub-basins (Chapter 3). In the same time, the basin is facing the challenges related to rapid population growth, uncontrolled urbanisation as well as climate change. Adequate quantification of hydrological processes across different spatial and temporal scales in the basin, and the drivers of change, is essential for prediction and strategic planning to ensure sustainable management of water resources in the Congo River Basin. Hydrological models are particularly important to generate the required information. However, the shortness of the available streamflow records, lack of spatial representativeness of the available streamflow gauging stations and the lack of understanding of the processes in channel-wetland exchanges, are the main challenges that constrain the use of traditional approaches to models development. They also contribute to increased uncertainty in the estimation of water resources across the basin (Chapter 1 and 2). Given this ungauged nature of the Congo River Basin, it is important to resort to hydrological modelling approaches that can reasonably quantify and model the uncertainty associated with water resources estimation (Chapter 4) to make hydrological predictions reliable. This study explores appropriate methods for hydrological predictions and water resources assessment in ungauged catchments of the Congo River Basin. In this context, the core modelling framework combines the quantification of uncertainty in constraint indices, hydrological modelling and hydrodynamic modelling. The latter accounts for channel-wetland exchanges in sub-basins where wetlands exert considerable influence on downstream flow regimes at the monthly time scale. The constraint indices are the characteristics of a sub-basin’s long-term hydrological behaviour and may reflect the dynamics of the different components of the catchment water balance such as climate, water storage and different runoff processes. Currently, six constraint indices namely the mean monthly runoff volume (MMQ in m3 *106), mean monthly groundwater recharge depth (MMR in mm), the 10th, 50th and 90th percentiles of the flow duration curve expressed as a fraction of MMQ (Q10/MMQ, Q50/MMQ, Q90/MMQ) and the percentage of time that zero flows are expected (%Zero), are used in the modelling approach. These were judged to be the minimum number of key indices that can discriminate between different hydrological responses. The constraint indices in the framework help to determine an uncertainty range within which behavioural model parameters of the expected hydrological response can be identified. Predictive equations of the constraint indices across all climate and physiographic regions of the Congo Basin were based only on the aridity index because it was the most influential sub-basin attribute (Chapter 5) for which quantitative information was available. The degree of uncertainty in the constraint Q10/MMQ and Q50/MMQ indices is less than 41%, while it is somewhat higher for the mean monthly runoff (MMQ) and Q90/MMQ constraint indices. The established uncertainty ranges of the constraint indices were tested in some selected sub-basins of the Congo Basin, including the Lualaba (93 sub-basins), Sangha (24 sub-basins), Oubangui (19 sub-basins), Batéké plateaux (4 sub-basins), Kasai (4 sub-basins) and Inkisi (3 sub-basins). The results proved useful through the application of a 2-stage uncertainty approach of the PITMAN model. However, it comes out of this study that the application of the original constraint indices ranges (Chapter 5) generated satisfactory simulation results in some areas, while in others both small and large adjustments were required to fully capture some aspects of the observed hydrological responses (Chapter 6). Part of the reason is attributed to the availability and quality of streamflow data used to develop the constraint indices ranges (Chapter 5). The main issue identified in the modelling process was whether the changes made to the original constraints at headwater-gauged sub-basins can be applied to ungauged upstream sub-basins to match the observed flow at downstream gauging stations. Ideally, only gauged sub-basin’s constraints can be easily revised based on the observed flow. However, the refinement made to gauged sub-basins alone may fail to substantially affect the results if ungauged upstream sub-basins exert a major impact on defining downstream hydrological response. The majority of gauging stations used in this analysis are located downstream of many upstream ungauged sub-basins and therefore adjustments were required in ungauged sub-basins. These adjustments consist of shifting the full range of a constraint index either towards higher or lower values, depending on the degree to which the simulated uncertainty bounds depart from the observed flow. While this modelling approach seems effective in capturing many aspects of the hydrological responses with a reduced level of uncertainty compared to a previous study, it is recommended that the approach be extended to the remaining parts of the Congo Basin and assessed under current and future development conditions including environmental changes. A 2D hydrodynamic river-wetland model (LISFLOOD-FP) has been used to explicitly represent the inundation process exchanges between river channels and wetland systems. The hydrodynamic modelling outputs are used to calibrate the PITMAN wetland sub-model parameters. The five hydrodynamic models constructed for Ankoro, Kamalondo, Kundelungu, Mweru and Tshiangalele wetland systems have been partially validated using independent estimates of inundation extents available from Landsat imagery. Other sources of data such as remote sensing of water level altimetry, SAR images and wetland storage estimates may be used to improve the validation results. However, the important objective in this study was to make sure that flow volume exchanges between river channels and their adjacent floodplains were being simulated realistically. The wetland sub-model parameters are calibrated in a spreadsheet version of the PITMAN wetland routine to achieve visual correspondence between the LISFLOOD-FP and PITMAN wetland sub-model outputs (Storage volumes and channel outputs). The hysteretic patterns of the river-wetland processes were quantified using hysteresis indices and were associated with the spill and return flow parameters of the wetland sub-model and eventually with the wetland morphometric characteristics. One example is the scale parameter of the return flow function (AA), which shows a good relationship with the average surface slope of the wetland when the coefficient parameter (BB) of the same function is kept constant to a value of 1.25. The same parameter (AA) is a good indicator of the wetland emptying mechanism. A small AA indicates a wetland that slowly releases its flow, resulting in a highly delayed and attenuated hydrological response in downstream sub-basins. This understanding has a practical advantage for the estimation of the PITMAN wetland parameters in the many areas where it is not possible, or where the resources are not available, to run complex hydrodynamic models (Chapter 7). The inclusion of these LISFLOOD-FP informed wetland parameters in the basin-scale hydrological modelling results in acceptable simulations for the lower Lualaba drainage system. The small wetlands, like Ankoro and Tshiangalele, have a negligible impact on downstream flow regimes, whereas large wetlands, such as Kamalondo and Mweru, have very large impacts. In general, the testing of the original constraint indices in the region of wetlands and further downstream of the Lualaba drainage system has shown acceptable results. However, there remains an unresolved uncertainty issue related to the under and over-estimation of some aspects of the hydrological response at both Mulongo and Ankoro, two gauging stations in the immediate downstream of the Kamalondo wetland system. It is difficult to attribute this uncertainty to Kamalondo wetland parameters alone because many of the incremental sub-basins contributing to wetland inflows are ungauged. The issue at Mulongo is the under simulation of low flow, while the high flows at the Ankoro gauging station are over-simulated. However, the pattern of the calibrated constraint indices in this region (Chapter 8) shows that the under simulation of low flow at Mulongo cannot be attributed to incremental sub-basins (between Bukama, Kapolowe and Mulongo gauging stations), because their Q90/MMQ constraint indices are even slightly above the original constraint ranges, but maintain a spatial consistency with sub-basins of other regions. Similarly, sub-basins located between Mulongo, Luvua and Ankoro gauging stations have high flow indices slightly below the original constraint ranges and therefore they are unlikely to be responsible for the over simulation of high flow at the Ankoro gauging station. These facts highlight the need for a further understanding of the complex wetland system of Kamalondo. Short-term data collection and monitoring programme are required. Important tributaries that drain to this wetland need to be monitored by installing water level loggers and periodically collecting flow data and river bathymetry. This programme should lead to the development of rating curves of wetland input tributaries. This would partially solve the unresolved uncertainty issues at the Ankoro and Mulongo gauging stations. The integrated modelling approach offers many opportunities in the Congo Basin. The quantified and modelled uncertainty helps to identify regions with high uncertainty and allows for the identification of various data collection and management strategies that can potentially contribute to the uncertainty reduction. The quantified channel-wetland exchanges contribute to the improvement of the overall knowledge of water resources estimation within the regions where the effects of wetlands are evident even at the monthly time scale. In contrast, ignoring uncertainty in the estimates of water resources availability means that water resources planning and management decisions in the Congo Basin will continue to be based on inadequate information and unquantified uncertainty, thus increasing the risk associated with water resources decision making. , Thesis (PhD) -- Faculty of Science, Institute for Water Research, 2021
- Full Text:
- Date Issued: 2021-04
Effect of increasing fossil shell flour levels on digestive and metabolic utilization, health, body weight change and wool production, and quality in Dohne-Merino wethers
- Authors: Ikusika, Olusegun Oyebade
- Date: 2020
- Subjects: Merino sheep Sheep -- Quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/18465 , vital:42542
- Description: The study's broad objective was to assess growth performance, blood and parasitic profiles, wool parameters, methane emission, and nutritional status of Dohne-Merino wethers fed diets supplemented with varying levels of fossil shell flour. Twenty-four Dohne-Merino wethers, averagely weighing 20.0±1.50 kg, were divided into four groups and used in this study. The effects of varying inclusion levels of fossil shell flour (FSF) (0, 2, 4, and 6 %) on feed intake, water intake, nutrient digestibility, N-retention, hematobiochemical and parasitic profiles, body condition scores, feed preference, wool parameters and methane output were determined. The influence of FSF's varying inclusion levels on fermentation parameters, in vitro true digestibility, and relative feed values were also determined. Wethers fed with 4% FSF inclusion level diet showed the highest (P<0.05) values for dry matter intake, average daily weight gain, N retention, (Nitrogen retention) and apparent digestibility of crude protein (CP), Ether Extract (EE) and Ash 6 % (P < 0.05). The urinary N and fecal N were lowest in wethers fed 4% FSF inclusion level and highest in those fed on diets without FSF (P < 0.05). Water intake was highest in wethers fed 0% FSF diet, followed by those fed on 4% and lowest in 6% FSF (P< 0.05). There was a significant increase in white blood cell counts in wethers fed on a diet with 4% and 6% FSF inclusion levels from day 10 to 100 compared to wethers fed on a diet with 0% and 2% FSF (P <0.05). Red blood cell counts also increased significantly in wethers fed on a diet containing 4% FSF, but a slight increase in wethers with 6 % FSF diet, throughout the experimental period (P < 0.05). Blood urea was highest in wethers fed 0% FSF inclusion level and lowest in 6% at day 30 to day 100. Wethers on 4% FSF diet showed an increase in blood urea from day 30 to day 100 (P < 0.05) while wethers on 0% and 2% remained unchanged (P<0.05) during this period and not different (P > 0.05) from wethers on 4% FSF as well. The total protein concentration, albumin, total bilirubin, Na, K, glucose, cholesterol, and liver enzymes were normal for wethers. However, serum creatinine level was lower in wethers fed on 4% FSF than those on 0% FSF (P < 0.01). Haemonchus and Coccidian fecal egg counts were low in wethers fed diets with 2%, 4%, and 6 % FSF (P < 0.01) compared 11 with wethers fed with 0% FSF inclusion level during the same period. The body condition score of wethers fed on diets with 2%, 4%, and 6% FSF inclusion levels were higher than those on 0% (P < 0.05). Wool yield, staple length, the coefficient variation of the fibre diameter, and fibre of wethers fed on diets with FSF were higher than those without FSF (P < 0.05). The fibre diameter of the wethers fed on FSF supplemented diets was the same as those on 0 % FSF (P > 0.05). The wethers spent more time on FSF supplemented diets and consumed more feed compared to that without FSF supplemented (P < 0.05). The levels of FSF inclusion in the diet affected the enteric methane output (ppm-m), where 4 % FSF had the highest enteric methane output while wethers on 2 % FSF had the lowest methane output (P < 0.05). Resting wethers produced more methane (g/day) than those feeding or standing (P < 0.05). Increasing levels of FSF did not affect ruminal temperature and pH. Ammonia-N increased with increasing FSF except in wethers fed on a diet with 4% FSF (P < 0.01). The total molar concentrations of the wethers' volatile fatty acids decreased with increasing FSF levels (P > 0.05). The acetic propionic ratio of the wethers also decreased except at a 4% inclusion level. The in vitro true digestibility dry matter (IVTDDM), in vitro true digestibility neutral detergent fibre (IVTDNDF), and in vitro true digestibility acid detergent fibre (IVTDADF) of the wethers decreased up to 4% FSF inclusion but tended to increase at 6% inclusion. This study's result as one of the pioneer studies in Dohne-Marino wethers showed that FSF treatment has the potential to improve the nutritional status of the animal and the animal performance and wool quality. Health-wise, FSF decrease nematode population and boost animal immunity as seen in RBC and WBC counts. It also can play a major role in protecting the environment, as seen in its reduction in feacal and urinary nitrogen, which is heavily involved in environmental pollution. Result also confirmed that the best period to target for methane mitigation in ruminants is the resting period. In conclusion, the inclusion of FSF in the diet of Dohne-Merino wethers has the potential to improve the overall performance, with a 4% FSF inclusion level having optimal productivity. However, future research is required to investigate FSF's effect on meat quality, rumen microbial community, in-vivo digestibility, and milk production.
- Full Text:
- Date Issued: 2020
- Authors: Ikusika, Olusegun Oyebade
- Date: 2020
- Subjects: Merino sheep Sheep -- Quality
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/18465 , vital:42542
- Description: The study's broad objective was to assess growth performance, blood and parasitic profiles, wool parameters, methane emission, and nutritional status of Dohne-Merino wethers fed diets supplemented with varying levels of fossil shell flour. Twenty-four Dohne-Merino wethers, averagely weighing 20.0±1.50 kg, were divided into four groups and used in this study. The effects of varying inclusion levels of fossil shell flour (FSF) (0, 2, 4, and 6 %) on feed intake, water intake, nutrient digestibility, N-retention, hematobiochemical and parasitic profiles, body condition scores, feed preference, wool parameters and methane output were determined. The influence of FSF's varying inclusion levels on fermentation parameters, in vitro true digestibility, and relative feed values were also determined. Wethers fed with 4% FSF inclusion level diet showed the highest (P<0.05) values for dry matter intake, average daily weight gain, N retention, (Nitrogen retention) and apparent digestibility of crude protein (CP), Ether Extract (EE) and Ash 6 % (P < 0.05). The urinary N and fecal N were lowest in wethers fed 4% FSF inclusion level and highest in those fed on diets without FSF (P < 0.05). Water intake was highest in wethers fed 0% FSF diet, followed by those fed on 4% and lowest in 6% FSF (P< 0.05). There was a significant increase in white blood cell counts in wethers fed on a diet with 4% and 6% FSF inclusion levels from day 10 to 100 compared to wethers fed on a diet with 0% and 2% FSF (P <0.05). Red blood cell counts also increased significantly in wethers fed on a diet containing 4% FSF, but a slight increase in wethers with 6 % FSF diet, throughout the experimental period (P < 0.05). Blood urea was highest in wethers fed 0% FSF inclusion level and lowest in 6% at day 30 to day 100. Wethers on 4% FSF diet showed an increase in blood urea from day 30 to day 100 (P < 0.05) while wethers on 0% and 2% remained unchanged (P<0.05) during this period and not different (P > 0.05) from wethers on 4% FSF as well. The total protein concentration, albumin, total bilirubin, Na, K, glucose, cholesterol, and liver enzymes were normal for wethers. However, serum creatinine level was lower in wethers fed on 4% FSF than those on 0% FSF (P < 0.01). Haemonchus and Coccidian fecal egg counts were low in wethers fed diets with 2%, 4%, and 6 % FSF (P < 0.01) compared 11 with wethers fed with 0% FSF inclusion level during the same period. The body condition score of wethers fed on diets with 2%, 4%, and 6% FSF inclusion levels were higher than those on 0% (P < 0.05). Wool yield, staple length, the coefficient variation of the fibre diameter, and fibre of wethers fed on diets with FSF were higher than those without FSF (P < 0.05). The fibre diameter of the wethers fed on FSF supplemented diets was the same as those on 0 % FSF (P > 0.05). The wethers spent more time on FSF supplemented diets and consumed more feed compared to that without FSF supplemented (P < 0.05). The levels of FSF inclusion in the diet affected the enteric methane output (ppm-m), where 4 % FSF had the highest enteric methane output while wethers on 2 % FSF had the lowest methane output (P < 0.05). Resting wethers produced more methane (g/day) than those feeding or standing (P < 0.05). Increasing levels of FSF did not affect ruminal temperature and pH. Ammonia-N increased with increasing FSF except in wethers fed on a diet with 4% FSF (P < 0.01). The total molar concentrations of the wethers' volatile fatty acids decreased with increasing FSF levels (P > 0.05). The acetic propionic ratio of the wethers also decreased except at a 4% inclusion level. The in vitro true digestibility dry matter (IVTDDM), in vitro true digestibility neutral detergent fibre (IVTDNDF), and in vitro true digestibility acid detergent fibre (IVTDADF) of the wethers decreased up to 4% FSF inclusion but tended to increase at 6% inclusion. This study's result as one of the pioneer studies in Dohne-Marino wethers showed that FSF treatment has the potential to improve the nutritional status of the animal and the animal performance and wool quality. Health-wise, FSF decrease nematode population and boost animal immunity as seen in RBC and WBC counts. It also can play a major role in protecting the environment, as seen in its reduction in feacal and urinary nitrogen, which is heavily involved in environmental pollution. Result also confirmed that the best period to target for methane mitigation in ruminants is the resting period. In conclusion, the inclusion of FSF in the diet of Dohne-Merino wethers has the potential to improve the overall performance, with a 4% FSF inclusion level having optimal productivity. However, future research is required to investigate FSF's effect on meat quality, rumen microbial community, in-vivo digestibility, and milk production.
- Full Text:
- Date Issued: 2020
Plaatje's African romance: the translation of tragedy in Mhudi and other writings
- Authors: Walter, Brian Ernest
- Date: 2001
- Subjects: Plaatje, Sol. T. (Solomon Tshekisho), 1876-1932. Mhudi Race in literature Politics in literature
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2188 , http://hdl.handle.net/10962/d1002230
- Description: This study brings together Plaatje’s politicaland literary visions, arguing that the one informs the other. Plaatje’s literary work is used as a starting point for the discussion, and the first chapter explores the relationship of his political and artistic visions. Mhudi is his definitive romance text, and it is argued that Plaatje’s romance visionin this text is reflected in his political thinking, and in turn reflected by it. His romance work was part of a literary romance tradition which Plaatje both drew upon and transformed, and thus the basic features of romance are explored in Chapter Two. Plaatje’s work is situated between two influential romance models, therefore Chapter Two also discusses the romances of Shakespeare, whomPlaatje read as reflectinga non-racial humanism that was translatable into the African context, in terms of political vision and of literary text. His other models were the colonial romances of Haggard. It is argued that, while Plaatje could glean many elements fromHaggardthat suited his purposes as an African, specifically a SouthAfrican, writer, he nevertheless—despite his own pro-British leanings, qualified though they might have been by the complexities of his colonial context—would not have represented Africa and Africans in terms of the exotic other in the way Haggard clearly did. Thus Plaatje, in terms of his romance vision, may have usedmanyofthe themesand techniques of Haggardianromance, but consistently qualified these colonial works by using the more classically shaped Shakespearean romance structure at the deep level of his work. The third chapter examines Haggard’s romance, but differentiates between two Haggardian types, the completed or resolved romance, whichis more classical in its form, and evokes an image of a completed quest, as well as the necessity of the quester entering the world again. Haggard’s “completed” African romance, it is argued, is resolved only in terms of a colonial vision. Chapter Four, by contrast, examines examples of his unresolved African romance, in which African ideals implode, and show themselves to be inneed of foreign intervention. It is argued that Haggard’s image of Africa was based on the unresolved or incomplete romance. His vision of Africa was such that it could not in itself provide the materialfor completed romance. This vision saw intervention as the only option for South Africa. While Plaatje uses elements of Haggard’s “incomplete” romance models when writing Mhudi, he handles both his narrative and politicalcommentaryin this text in terms of his own politicalthought. This non-racial politicalvisionis guided by his belief that virtue and vice are not the monopoly of any colour, a non-racialism he associates with Shakespeare. However, within the context of the South Africa of his fictionand of his life, this non-racial ideal is constantly under threat. It is partly threatened by political forces, but also challenged by moral changes within individuals and societies. In Chapter Five the examination of Plaatje’s work begins withhis Boer War Diary, inwhicha romance structure is sought beneath his diurnal observations and political optimismduring a time of warfare and siege. The discussion of this text is followed by a reading of Native Life in South Africa in which it is argued that Plaatje looks, in the midst of personal and social suffering, for that which can translate a tragic situation into romance resolution. “Translation” is used in a broad sense, echoing Plaatje’s view of the importance of translation for cross-cultural understanding and harmony. The arguments of Chapter Five are extended into Chapter Six, where a reading of Mhudi places emphasis on the possibilities of change implied in romance. Plaatje’s non-racial humanism recognizes the great potential for injustice and human suffering within the context of South African racism, but constantly seeks to translate such suffering into the triumph of romance. While the narrative of Mhudi concludes on a romance peak, tensions between the tragic and romance possibilities alert the reader to the sense that, despite its romance resolution, something has been lost in the translation of the potential tragedy into romance.
- Full Text:
- Date Issued: 2001
- Authors: Walter, Brian Ernest
- Date: 2001
- Subjects: Plaatje, Sol. T. (Solomon Tshekisho), 1876-1932. Mhudi Race in literature Politics in literature
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2188 , http://hdl.handle.net/10962/d1002230
- Description: This study brings together Plaatje’s politicaland literary visions, arguing that the one informs the other. Plaatje’s literary work is used as a starting point for the discussion, and the first chapter explores the relationship of his political and artistic visions. Mhudi is his definitive romance text, and it is argued that Plaatje’s romance visionin this text is reflected in his political thinking, and in turn reflected by it. His romance work was part of a literary romance tradition which Plaatje both drew upon and transformed, and thus the basic features of romance are explored in Chapter Two. Plaatje’s work is situated between two influential romance models, therefore Chapter Two also discusses the romances of Shakespeare, whomPlaatje read as reflectinga non-racial humanism that was translatable into the African context, in terms of political vision and of literary text. His other models were the colonial romances of Haggard. It is argued that, while Plaatje could glean many elements fromHaggardthat suited his purposes as an African, specifically a SouthAfrican, writer, he nevertheless—despite his own pro-British leanings, qualified though they might have been by the complexities of his colonial context—would not have represented Africa and Africans in terms of the exotic other in the way Haggard clearly did. Thus Plaatje, in terms of his romance vision, may have usedmanyofthe themesand techniques of Haggardianromance, but consistently qualified these colonial works by using the more classically shaped Shakespearean romance structure at the deep level of his work. The third chapter examines Haggard’s romance, but differentiates between two Haggardian types, the completed or resolved romance, whichis more classical in its form, and evokes an image of a completed quest, as well as the necessity of the quester entering the world again. Haggard’s “completed” African romance, it is argued, is resolved only in terms of a colonial vision. Chapter Four, by contrast, examines examples of his unresolved African romance, in which African ideals implode, and show themselves to be inneed of foreign intervention. It is argued that Haggard’s image of Africa was based on the unresolved or incomplete romance. His vision of Africa was such that it could not in itself provide the materialfor completed romance. This vision saw intervention as the only option for South Africa. While Plaatje uses elements of Haggard’s “incomplete” romance models when writing Mhudi, he handles both his narrative and politicalcommentaryin this text in terms of his own politicalthought. This non-racial politicalvisionis guided by his belief that virtue and vice are not the monopoly of any colour, a non-racialism he associates with Shakespeare. However, within the context of the South Africa of his fictionand of his life, this non-racial ideal is constantly under threat. It is partly threatened by political forces, but also challenged by moral changes within individuals and societies. In Chapter Five the examination of Plaatje’s work begins withhis Boer War Diary, inwhicha romance structure is sought beneath his diurnal observations and political optimismduring a time of warfare and siege. The discussion of this text is followed by a reading of Native Life in South Africa in which it is argued that Plaatje looks, in the midst of personal and social suffering, for that which can translate a tragic situation into romance resolution. “Translation” is used in a broad sense, echoing Plaatje’s view of the importance of translation for cross-cultural understanding and harmony. The arguments of Chapter Five are extended into Chapter Six, where a reading of Mhudi places emphasis on the possibilities of change implied in romance. Plaatje’s non-racial humanism recognizes the great potential for injustice and human suffering within the context of South African racism, but constantly seeks to translate such suffering into the triumph of romance. While the narrative of Mhudi concludes on a romance peak, tensions between the tragic and romance possibilities alert the reader to the sense that, despite its romance resolution, something has been lost in the translation of the potential tragedy into romance.
- Full Text:
- Date Issued: 2001
Social learning for public participation in environmental governance: the case of Knysna Municipality
- Authors: Currie, Bianca
- Date: 2018
- Subjects: Environmental policy -- South Africa -- Knysna -- Social aspects , Environmental management -- South Africa -- Knysna
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/29852 , vital:30785
- Description: Democratic environmental governance in complex systems requires an adaptive management approach involving a diversity of stakeholders in collaborative learning and decision-making. The decisions are value-laden, and local municipalities are struggling to reconcile the diversity of values, and balance varied and diverse social and ecological needs, for sustainability. Social learning has emerged as a promising approach but the challenge lies in effective implementation, practice and assessment of social learning. This thesis explored public participation practices in environmental governance in the Knysna Municipality and went on to develop a social learning procedural model for public participation, as well as assessment criteria for monitoring social learning processes. The model and criteria provide a foundation and the tools needed to operationalise social learning for adaptive management in environmental governance in complex systems.
- Full Text:
- Date Issued: 2018
- Authors: Currie, Bianca
- Date: 2018
- Subjects: Environmental policy -- South Africa -- Knysna -- Social aspects , Environmental management -- South Africa -- Knysna
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/29852 , vital:30785
- Description: Democratic environmental governance in complex systems requires an adaptive management approach involving a diversity of stakeholders in collaborative learning and decision-making. The decisions are value-laden, and local municipalities are struggling to reconcile the diversity of values, and balance varied and diverse social and ecological needs, for sustainability. Social learning has emerged as a promising approach but the challenge lies in effective implementation, practice and assessment of social learning. This thesis explored public participation practices in environmental governance in the Knysna Municipality and went on to develop a social learning procedural model for public participation, as well as assessment criteria for monitoring social learning processes. The model and criteria provide a foundation and the tools needed to operationalise social learning for adaptive management in environmental governance in complex systems.
- Full Text:
- Date Issued: 2018
Comparative analysis of the known Hop1b and the novel Hop1a isoforms of the Hop gene
- Authors: Makhubu, Portia
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164311 , vital:41108 , doi:10.21504/10962/164311
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
- Authors: Makhubu, Portia
- Date: 2020
- Subjects: Uncatalogued
- Language: English
- Type: thesis , text , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/164311 , vital:41108 , doi:10.21504/10962/164311
- Description: Thesis (PhD)--Rhodes University, Faculty of Science, Biochemistry and Microbiology, 2020
- Full Text:
- Date Issued: 2020
Knowledge practices and student access and success in General Chemistry at a Large South African University
- Authors: Mtombeni, Thabile Nokuthula
- Date: 2018
- Subjects: Chemistry -- Study and teaching (Higher) -- South Africa , Knowledge management , Education, Higher -- Curricula -- South Africa , Critical realism , Social integration -- South Africa , Educational equalization -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62873 , vital:28305
- Description: This dissertation reports on an investigation into the structuring principles of the General Chemistry curriculum at a Large South African University (LSAU). Student learning in the introductory modules of General Chemistry is critical for access to a range of fields since it is a requisite course for a variety of degree programmes. However, there is ample evidence that success in this subject remains a major challenge, particularly for black students. My quest in this study was to explore how the curriculum could enable greater epistemic access and thus include more students in science programmes at the LSAU. I investigated the organising principles underlying the curriculum practices of the General Chemistry module and explored the effects of the curriculum structure on student learning. Theoretically and conceptually, the study was underpinned by a social realist approach which holds that knowledge is stratified, differentiated, and has real emergent properties, powers and effects. The research question that I attempted to answer in this study was: How do knowledge practices privileged in the General Chemistry curriculum at the LSAU enable or constrain student learning? I adopted an intensive research design approach to conduct a qualitative case study using social realism and LCT as theoretical and analytical lenses. I used empirical data such as curriculum documents and interviews with lecturers to uncover the underlying generative mechanisms of the curriculum. I adopted a multi-layered data analysis process to make visible the underlying organising principles informing knowledge practices in the curriculum so that I could explain their potential effects on student learning. The first level of analysis explored the context of the curriculum and associated knowledge practices, and examined the pedagogic discourse evident in the curriculum. The second level of analysis revealed the inner logic structuring the curriculum and the associated knowledge practices. I used Maton’s Legitimation Code Theory (LCT): Specialisation to identify the specialisation codes, gazes and insights generated by the curriculum. For the third level of analysis, LCT: Semantics was used to generate the semantic profiles of learning activities to determine the extent to which the curriculum structure made cumulative learning possible. From the findings, it is evident that the verticality of knowledge in General Chemistry points to a recontextualising principle that prescribes the selection and arrangement of knowledge, and the special relationship of actors and discourses. As a result, the strong framing of the instructional discourse of General Chemistry curriculum structure is likely to constrain epistemological access for large numbers of students. In order to improve epistemological access to the field, weaker framing of the instructional discourse in introductory science is necessary. Weaker framing of the General Chemistry curriculum would require, in particular, changes to pacing, and that the evaluative criteria are made explicit. This is especially necessary when certain abstract and complex curricular content is taught, especially in the first semester. The findings also indicate that the nature of the organising principles in the curriculum are significant for improving epistemological access to knowledge. In terms of LCT: Specialisation, the General Chemistry curriculum generated a knowledge code and downplayed differences among social categories of students, thus positioning all equally in relation to the knowledge and practices of the field. Therefore, the structuring of the curriculum emphasises and legitimates students who have attained specialist knowledge without considering the nature of the new student coming into the educational setting. Simply, what is privileged is both the object of study (theoretical knowledge) and how it is studied (procedural knowledge). This finding is in line with the general outcomes of Chemistry education. In addition, the purist insight generated by the curriculum further attests to where the emphasis is placed in the curriculum. I argue that the lack of social relations in the curriculum poses a challenge for the holistic development of students as science knowers. The analysis of the learning activities shows rapid code shifts that indicate changes in cognitive demand and modes of thinking required of students. I argue that signposting the changes in complexity of knowledge and in the mode of thinking required could make learning, and thus epistemological access, more possible. Given the imperative of access to powerful knowledge, I contend that the curriculum should be reshaped to enable epistemological access for more students.
- Full Text:
- Date Issued: 2018
- Authors: Mtombeni, Thabile Nokuthula
- Date: 2018
- Subjects: Chemistry -- Study and teaching (Higher) -- South Africa , Knowledge management , Education, Higher -- Curricula -- South Africa , Critical realism , Social integration -- South Africa , Educational equalization -- South Africa
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/62873 , vital:28305
- Description: This dissertation reports on an investigation into the structuring principles of the General Chemistry curriculum at a Large South African University (LSAU). Student learning in the introductory modules of General Chemistry is critical for access to a range of fields since it is a requisite course for a variety of degree programmes. However, there is ample evidence that success in this subject remains a major challenge, particularly for black students. My quest in this study was to explore how the curriculum could enable greater epistemic access and thus include more students in science programmes at the LSAU. I investigated the organising principles underlying the curriculum practices of the General Chemistry module and explored the effects of the curriculum structure on student learning. Theoretically and conceptually, the study was underpinned by a social realist approach which holds that knowledge is stratified, differentiated, and has real emergent properties, powers and effects. The research question that I attempted to answer in this study was: How do knowledge practices privileged in the General Chemistry curriculum at the LSAU enable or constrain student learning? I adopted an intensive research design approach to conduct a qualitative case study using social realism and LCT as theoretical and analytical lenses. I used empirical data such as curriculum documents and interviews with lecturers to uncover the underlying generative mechanisms of the curriculum. I adopted a multi-layered data analysis process to make visible the underlying organising principles informing knowledge practices in the curriculum so that I could explain their potential effects on student learning. The first level of analysis explored the context of the curriculum and associated knowledge practices, and examined the pedagogic discourse evident in the curriculum. The second level of analysis revealed the inner logic structuring the curriculum and the associated knowledge practices. I used Maton’s Legitimation Code Theory (LCT): Specialisation to identify the specialisation codes, gazes and insights generated by the curriculum. For the third level of analysis, LCT: Semantics was used to generate the semantic profiles of learning activities to determine the extent to which the curriculum structure made cumulative learning possible. From the findings, it is evident that the verticality of knowledge in General Chemistry points to a recontextualising principle that prescribes the selection and arrangement of knowledge, and the special relationship of actors and discourses. As a result, the strong framing of the instructional discourse of General Chemistry curriculum structure is likely to constrain epistemological access for large numbers of students. In order to improve epistemological access to the field, weaker framing of the instructional discourse in introductory science is necessary. Weaker framing of the General Chemistry curriculum would require, in particular, changes to pacing, and that the evaluative criteria are made explicit. This is especially necessary when certain abstract and complex curricular content is taught, especially in the first semester. The findings also indicate that the nature of the organising principles in the curriculum are significant for improving epistemological access to knowledge. In terms of LCT: Specialisation, the General Chemistry curriculum generated a knowledge code and downplayed differences among social categories of students, thus positioning all equally in relation to the knowledge and practices of the field. Therefore, the structuring of the curriculum emphasises and legitimates students who have attained specialist knowledge without considering the nature of the new student coming into the educational setting. Simply, what is privileged is both the object of study (theoretical knowledge) and how it is studied (procedural knowledge). This finding is in line with the general outcomes of Chemistry education. In addition, the purist insight generated by the curriculum further attests to where the emphasis is placed in the curriculum. I argue that the lack of social relations in the curriculum poses a challenge for the holistic development of students as science knowers. The analysis of the learning activities shows rapid code shifts that indicate changes in cognitive demand and modes of thinking required of students. I argue that signposting the changes in complexity of knowledge and in the mode of thinking required could make learning, and thus epistemological access, more possible. Given the imperative of access to powerful knowledge, I contend that the curriculum should be reshaped to enable epistemological access for more students.
- Full Text:
- Date Issued: 2018
Girls here and boys there : participatory visual methodology as pedagogy to facilitate gender sensitive practices with pre-service foundation phase teachers
- Authors: Notshulwana, Robin Anne
- Date: 2020
- Subjects: Gender identity -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/49385 , vital:41700
- Description: This study explores how participatory visual methodology (PVM) might facilitate a deeper understanding of gender sensitive practices (GSP) in Foundation Phase (FP) pre-service teachers. Foundation Phase classrooms are not impervious to unequal gender practices and despite policies that promote gender equitable practices in schools and in society in general, most South African schools still engage in gendered practices that perpetuate inequality and gender based violence (GBV). While the topic of gender currently features in a South African university FP curriculum with the intention of promoting social justice, the pedagogy used to enable pre-service FP teachers to understand how gender works in schools seems to do nothing more than describe the problem and give cursory suggestions for creating gender equitable practices. Teachers are often unaware of how their own gendered identity influences their facilitation of the curriculum in a gendered way. This is important in South Africa, where gender inequality remains a problem and GBV is rife. This study adopted a qualitative approach and is located within the critical paradigm applying the principles of PVM. It drew on feminist poststructuralism and feminist pedagogy as theoretical lenses to frame the study and to make meaning of the data. Participants in the study were five female pre-service FP teachers who were purposively selected. Data were generated through the visual methods of family photo album, drawing and participatory video, which were first analysed using participatory analysis, and then using thematic analysis. The main purpose of the research was to explore how PVM can facilitate a deeper awareness of GSP in pre-service FP teachers. The secondary aim was to explore their understandings of gender and GSP and how these understandings might facilitate or inhibit GSP among pre-service FP teachers. The pre-service FP teachers’ understandings of gender were elicited using the self as an entry point to explore their own gendered identities which demonstrated their somewhat narrow understanding of how gender is reified in society through mechanisms such as dress and particular performances. They further understood that their own gendered selves can shift and change with time and context. Their understanding of gender further informed their understanding of GSP. The pre-service FP teachers understood GSP as going beyond interchanging roles of girls and boys and that it meant constantly engaging with their own understandings of gender; to review their constructions of FP learners, to see pedagogical moments to teach gender sensitivity, and to recognise that GSP extends beyond the classroom. Finally, the pre-service FP teachers articulated the circumstances that might enable or inhibit their GSP in their classrooms. They recognised how the powerful constructions of gender in a society influence their work, and how, in turn their work might influence society. This translated into them understanding how the ethos of the school might mirror and sustain the hegemonic discourse of society and at the same time how they might begin to question and disrupt the discourse sustained in school. The teacher education programme, with a vested interest in gender equality, is an important mechanism to begin disrupting hegemonic discourses perpetuated in schools. The findings suggest that through its potential for reflexivity and criticality, PVM enabled the pre-service FP teachers to see how their constructions of gender influence their own practices in schools. The findings have implications for FP teacher education programmes in the South African context. Faculties of education could revisit their curriculum to ensure that gender is infused throughout the curriculum, but more importantly, could consider ‘starting with the self’ (Kirk, 2009) as an impetus to learn about how gender is reified in society and in schools. In doing so, faculties of education could also consider tools of analysis such as a feminist poststructural theory to enable the pre-service FP teachers to deepen their understandings but also support the potential to articulate and make meaning of their experiences. Teacher educators could revisit their curriculum content to determine whether the content might perpetuate a narrow view of learning and learners especially with regards to gender and considering pedagogical choices that develop pre-service teachers’ ability to cultivate classroom environments that promote gender equality. Starting with the self is an entry point for pre-service FP teachers to examine their own understanding of gender and see how this might enable GSP in their professional work. PVM, aligned with a feminist pedagogy and feminist poststructuralism, facilitated such a process.
- Full Text:
- Date Issued: 2020
- Authors: Notshulwana, Robin Anne
- Date: 2020
- Subjects: Gender identity -- Psychological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/49385 , vital:41700
- Description: This study explores how participatory visual methodology (PVM) might facilitate a deeper understanding of gender sensitive practices (GSP) in Foundation Phase (FP) pre-service teachers. Foundation Phase classrooms are not impervious to unequal gender practices and despite policies that promote gender equitable practices in schools and in society in general, most South African schools still engage in gendered practices that perpetuate inequality and gender based violence (GBV). While the topic of gender currently features in a South African university FP curriculum with the intention of promoting social justice, the pedagogy used to enable pre-service FP teachers to understand how gender works in schools seems to do nothing more than describe the problem and give cursory suggestions for creating gender equitable practices. Teachers are often unaware of how their own gendered identity influences their facilitation of the curriculum in a gendered way. This is important in South Africa, where gender inequality remains a problem and GBV is rife. This study adopted a qualitative approach and is located within the critical paradigm applying the principles of PVM. It drew on feminist poststructuralism and feminist pedagogy as theoretical lenses to frame the study and to make meaning of the data. Participants in the study were five female pre-service FP teachers who were purposively selected. Data were generated through the visual methods of family photo album, drawing and participatory video, which were first analysed using participatory analysis, and then using thematic analysis. The main purpose of the research was to explore how PVM can facilitate a deeper awareness of GSP in pre-service FP teachers. The secondary aim was to explore their understandings of gender and GSP and how these understandings might facilitate or inhibit GSP among pre-service FP teachers. The pre-service FP teachers’ understandings of gender were elicited using the self as an entry point to explore their own gendered identities which demonstrated their somewhat narrow understanding of how gender is reified in society through mechanisms such as dress and particular performances. They further understood that their own gendered selves can shift and change with time and context. Their understanding of gender further informed their understanding of GSP. The pre-service FP teachers understood GSP as going beyond interchanging roles of girls and boys and that it meant constantly engaging with their own understandings of gender; to review their constructions of FP learners, to see pedagogical moments to teach gender sensitivity, and to recognise that GSP extends beyond the classroom. Finally, the pre-service FP teachers articulated the circumstances that might enable or inhibit their GSP in their classrooms. They recognised how the powerful constructions of gender in a society influence their work, and how, in turn their work might influence society. This translated into them understanding how the ethos of the school might mirror and sustain the hegemonic discourse of society and at the same time how they might begin to question and disrupt the discourse sustained in school. The teacher education programme, with a vested interest in gender equality, is an important mechanism to begin disrupting hegemonic discourses perpetuated in schools. The findings suggest that through its potential for reflexivity and criticality, PVM enabled the pre-service FP teachers to see how their constructions of gender influence their own practices in schools. The findings have implications for FP teacher education programmes in the South African context. Faculties of education could revisit their curriculum to ensure that gender is infused throughout the curriculum, but more importantly, could consider ‘starting with the self’ (Kirk, 2009) as an impetus to learn about how gender is reified in society and in schools. In doing so, faculties of education could also consider tools of analysis such as a feminist poststructural theory to enable the pre-service FP teachers to deepen their understandings but also support the potential to articulate and make meaning of their experiences. Teacher educators could revisit their curriculum content to determine whether the content might perpetuate a narrow view of learning and learners especially with regards to gender and considering pedagogical choices that develop pre-service teachers’ ability to cultivate classroom environments that promote gender equality. Starting with the self is an entry point for pre-service FP teachers to examine their own understanding of gender and see how this might enable GSP in their professional work. PVM, aligned with a feminist pedagogy and feminist poststructuralism, facilitated such a process.
- Full Text:
- Date Issued: 2020
Structural bioinformatics studies and tool development related to drug discovery
- Authors: Hatherley, Rowan
- Date: 2016
- Subjects: Structural bioinformatics , Drug development , Natural products -- Databases , Natural products -- Biotechnology , Sequence alignment (Bioinformatics) , Malaria -- Chemotherapy , Heat shock proteins , Plasmodium falciparum
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4164 , http://hdl.handle.net/10962/d1020021
- Description: This thesis is divided into two distinct sections which can be combined under the broad umbrella of structural bioinformatics studies related to drug discovery. The first section involves the establishment of an online South African natural products database. Natural products (NPs) are chemical entities synthesised in nature and are unrivalled in their structural complexity, chemical diversity, and biological specificity, which has long made them crucial to the drug discovery process. South Africa is rich in both plant and marine biodiversity and a great deal of research has gone into isolating compounds from organisms found in this country. However, there is no official database containing this information, making it difficult to access for research purposes. This information was extracted manually from literature to create a database of South African natural products. In order to make the information accessible to the general research community, a website, named “SANCDB”, was built to enable compounds to be quickly and easily searched for and downloaded in a number of different chemical formats. The content of the database was assessed and compared to other established natural product databases. Currently, SANCDB is the only database of natural products in Africa with an online interface. The second section of the thesis was aimed at performing structural characterisation of proteins with the potential to be targeted for antimalarial drug therapy. This looked specifically at 1) The interactions between an exported heat shock protein (Hsp) from Plasmodium falciparum (P. falciparum), PfHsp70-x and various host and exported parasite J proteins, as well as 2) The interface between PfHsp90 and the heat shock organising protein (PfHop). The PfHsp70-x:J protein study provided additional insight into how these two proteins potentially interact. Analysis of the PfHsp90:PfHop also provided a structural insight into the interaction interface between these two proteins and identified residues that could be targeted due to their contribution to the stability of the Hsp90:Hop binding complex and differences between parasite and human proteins. These studies inspired the development of a homology modelling tool, which can be used to assist researchers with homology modelling, while providing them with step-by-step control over the entire process. This thesis presents the establishment of a South African NP database and the development of a homology modelling tool, inspired by protein structural studies. When combined, these two applications have the potential to contribute greatly towards in silico drug discovery research.
- Full Text:
- Date Issued: 2016
- Authors: Hatherley, Rowan
- Date: 2016
- Subjects: Structural bioinformatics , Drug development , Natural products -- Databases , Natural products -- Biotechnology , Sequence alignment (Bioinformatics) , Malaria -- Chemotherapy , Heat shock proteins , Plasmodium falciparum
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4164 , http://hdl.handle.net/10962/d1020021
- Description: This thesis is divided into two distinct sections which can be combined under the broad umbrella of structural bioinformatics studies related to drug discovery. The first section involves the establishment of an online South African natural products database. Natural products (NPs) are chemical entities synthesised in nature and are unrivalled in their structural complexity, chemical diversity, and biological specificity, which has long made them crucial to the drug discovery process. South Africa is rich in both plant and marine biodiversity and a great deal of research has gone into isolating compounds from organisms found in this country. However, there is no official database containing this information, making it difficult to access for research purposes. This information was extracted manually from literature to create a database of South African natural products. In order to make the information accessible to the general research community, a website, named “SANCDB”, was built to enable compounds to be quickly and easily searched for and downloaded in a number of different chemical formats. The content of the database was assessed and compared to other established natural product databases. Currently, SANCDB is the only database of natural products in Africa with an online interface. The second section of the thesis was aimed at performing structural characterisation of proteins with the potential to be targeted for antimalarial drug therapy. This looked specifically at 1) The interactions between an exported heat shock protein (Hsp) from Plasmodium falciparum (P. falciparum), PfHsp70-x and various host and exported parasite J proteins, as well as 2) The interface between PfHsp90 and the heat shock organising protein (PfHop). The PfHsp70-x:J protein study provided additional insight into how these two proteins potentially interact. Analysis of the PfHsp90:PfHop also provided a structural insight into the interaction interface between these two proteins and identified residues that could be targeted due to their contribution to the stability of the Hsp90:Hop binding complex and differences between parasite and human proteins. These studies inspired the development of a homology modelling tool, which can be used to assist researchers with homology modelling, while providing them with step-by-step control over the entire process. This thesis presents the establishment of a South African NP database and the development of a homology modelling tool, inspired by protein structural studies. When combined, these two applications have the potential to contribute greatly towards in silico drug discovery research.
- Full Text:
- Date Issued: 2016
Structural studies on some enterobacterial capsular antigens
- Authors: Whittaker, Darryl Vanstone
- Date: 1994
- Subjects: Bacterial antigens -- Analysis Antigens Enterobacteriaceae Escherichia coli Klebsiella
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3803 , http://hdl.handle.net/10962/d1003281
- Description: The investigations presented in this thesis form part of a systematic international effort to establish the structures of the capsules produced by the bacterial genera, Escherichia coli and Klebsiella (family enterobacteriaceae). These bacteria are of medical interest as they are opportunistic pathogens and are frequently responsible for serious infections in animals and man. Invasive strains are invariably surrounded by a structurally complex polysaccharide capsule which contributes to the organism's ability to attenuate non-specific host defence mechanisms or, in some instances, to completely prevent an immune response. A knowledge of the chemical composition and structure of the capsule is, therefore, of great value as it provides insight into the mechanisms involved in this process. The E. coli, in particular, have generated considerable interest as their capsules are more structurally diverse and cross-reactivity with other, more pathogenic bacteria has also been demonstrated. Accordingly, the structures of three previously unstudied E. coli K-antigens viz. those produced by serotypes 020:K83:H26, 020:K84:H26, and 09:K48:H9 have been established by chemical and spectroscopic means and are presented in this thesis. In addition, a reinvestigation of the structure of the capsule produced by Klebsiella K15 using a novel enzymatic approach was also undertaken and a revised structure is proposed . The E. coli K48 polysaccharide is of special interest as it was found to contain a new diacetamido trideoxy hexose hitherto unrecorded. A synthesis for this saccharide is also presented. Finally, the application of lithium dissolved in ethylenediamine for the degradation of amino sugar-containing polysaccharides was also investigated using the capsular polysaccharides produced by E. coli serotypes K38 and K84 as model compounds.
- Full Text:
- Date Issued: 1994
- Authors: Whittaker, Darryl Vanstone
- Date: 1994
- Subjects: Bacterial antigens -- Analysis Antigens Enterobacteriaceae Escherichia coli Klebsiella
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3803 , http://hdl.handle.net/10962/d1003281
- Description: The investigations presented in this thesis form part of a systematic international effort to establish the structures of the capsules produced by the bacterial genera, Escherichia coli and Klebsiella (family enterobacteriaceae). These bacteria are of medical interest as they are opportunistic pathogens and are frequently responsible for serious infections in animals and man. Invasive strains are invariably surrounded by a structurally complex polysaccharide capsule which contributes to the organism's ability to attenuate non-specific host defence mechanisms or, in some instances, to completely prevent an immune response. A knowledge of the chemical composition and structure of the capsule is, therefore, of great value as it provides insight into the mechanisms involved in this process. The E. coli, in particular, have generated considerable interest as their capsules are more structurally diverse and cross-reactivity with other, more pathogenic bacteria has also been demonstrated. Accordingly, the structures of three previously unstudied E. coli K-antigens viz. those produced by serotypes 020:K83:H26, 020:K84:H26, and 09:K48:H9 have been established by chemical and spectroscopic means and are presented in this thesis. In addition, a reinvestigation of the structure of the capsule produced by Klebsiella K15 using a novel enzymatic approach was also undertaken and a revised structure is proposed . The E. coli K48 polysaccharide is of special interest as it was found to contain a new diacetamido trideoxy hexose hitherto unrecorded. A synthesis for this saccharide is also presented. Finally, the application of lithium dissolved in ethylenediamine for the degradation of amino sugar-containing polysaccharides was also investigated using the capsular polysaccharides produced by E. coli serotypes K38 and K84 as model compounds.
- Full Text:
- Date Issued: 1994
Population dynamics of the raggedtooth shark (carcharias taurus) along the east coast of South Africa
- Authors: Dicken, Matthew Laurence
- Date: 2006
- Subjects: Sharks -- South Africa Shark fisheries -- South Africa Fish populations -- South Africa Sand tiger shark Fish tagging -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5310 , http://hdl.handle.net/10962/d1005155
- Description: This thesis develops the first open population model for any shark species worldwide using the Cormack-Jolly-Seber (CJS) model. In conjunction with a tagging study, five auxiliary studies were conducted to investigate stock structure, post-release mortality, tag shedding, and tag-reporting rates. The results from each of the studies were used to correct for any violations of the models assumptions to provide the first unbiased estimates of survival and abundance for the raggedtooth shark (Carcharias taurus) in South Africa. The C. taurus population exhibited complex stock structuring, by size and sex. Competitive shore anglers fished an estimated 37, 820 fishing days.year⁻¹ (95% C.I. = 28, 281 - 47, 359 days.year⁻¹) for sharks, and caught 1764 (95% C.I. = 321 – 3207) C. taurus. Although released alive, post-release mortality ranged from 3.85% for young-of-the-year sharks to 18.46% for adult sharks. Between 1984 and 2004, a total of 3471 C. taurus were tagged. In all, 302-tagged sharks (8.7%) were recaptured. Both juvenile (< 1.8 m TL) and adult sharks (> 1.8 m TL) displayed philopatric behaviour for specific parts of their ranges, including gestating and parturition areas. Significant differences were observed in the percentage of recaptures between the different tag types, tagging programs, individual taggers and capture methods used to tag sharks. The annual tag retention rate for juvenile sharks, 94.19% (95% C.I. = 80.68% - 100.00%) was significantly higher than for adult sharks, estimated at 29.00% (95% C.I. = 6.76% - 64.39%). Tag reporting rates, from fishermen varied both spatially and temporally from 0.28 (95% C.I. = 0.00 – 0.63) to 0.77 (95% C.I. = 0.56 – 0.97). Associated tag wound damage and biofouling growth indicated that B-type tags were a suitable tag type for use on C. taurus, whereas C-type tags were not. The CJS bias-adjusted estimate for juvenile survival was 0.456 (95% C.I. = 0.367 – 0.516) and for adult sharks, 0.865 (95% C.I. = 0.795 – 0.915). From 1984 to 2004 the mean bias-adjusted population size for juvenile sharks was estimated at 3506 (95% C.I. = 2433 – 4350) and for adult sharks, 5899 (95% C.I. = 7216 – 11904). Trends in abundance over the 20-year study period indicated a stable, healthy population.
- Full Text:
- Date Issued: 2006
- Authors: Dicken, Matthew Laurence
- Date: 2006
- Subjects: Sharks -- South Africa Shark fisheries -- South Africa Fish populations -- South Africa Sand tiger shark Fish tagging -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5310 , http://hdl.handle.net/10962/d1005155
- Description: This thesis develops the first open population model for any shark species worldwide using the Cormack-Jolly-Seber (CJS) model. In conjunction with a tagging study, five auxiliary studies were conducted to investigate stock structure, post-release mortality, tag shedding, and tag-reporting rates. The results from each of the studies were used to correct for any violations of the models assumptions to provide the first unbiased estimates of survival and abundance for the raggedtooth shark (Carcharias taurus) in South Africa. The C. taurus population exhibited complex stock structuring, by size and sex. Competitive shore anglers fished an estimated 37, 820 fishing days.year⁻¹ (95% C.I. = 28, 281 - 47, 359 days.year⁻¹) for sharks, and caught 1764 (95% C.I. = 321 – 3207) C. taurus. Although released alive, post-release mortality ranged from 3.85% for young-of-the-year sharks to 18.46% for adult sharks. Between 1984 and 2004, a total of 3471 C. taurus were tagged. In all, 302-tagged sharks (8.7%) were recaptured. Both juvenile (< 1.8 m TL) and adult sharks (> 1.8 m TL) displayed philopatric behaviour for specific parts of their ranges, including gestating and parturition areas. Significant differences were observed in the percentage of recaptures between the different tag types, tagging programs, individual taggers and capture methods used to tag sharks. The annual tag retention rate for juvenile sharks, 94.19% (95% C.I. = 80.68% - 100.00%) was significantly higher than for adult sharks, estimated at 29.00% (95% C.I. = 6.76% - 64.39%). Tag reporting rates, from fishermen varied both spatially and temporally from 0.28 (95% C.I. = 0.00 – 0.63) to 0.77 (95% C.I. = 0.56 – 0.97). Associated tag wound damage and biofouling growth indicated that B-type tags were a suitable tag type for use on C. taurus, whereas C-type tags were not. The CJS bias-adjusted estimate for juvenile survival was 0.456 (95% C.I. = 0.367 – 0.516) and for adult sharks, 0.865 (95% C.I. = 0.795 – 0.915). From 1984 to 2004 the mean bias-adjusted population size for juvenile sharks was estimated at 3506 (95% C.I. = 2433 – 4350) and for adult sharks, 5899 (95% C.I. = 7216 – 11904). Trends in abundance over the 20-year study period indicated a stable, healthy population.
- Full Text:
- Date Issued: 2006