Investigating the effects of form-focused activities on the Acquisition of articles and pronouns in English amongst Grade 11 Xhosa learners
- Authors: White, Emma Lindsey
- Date: 2010
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:8362 , http://hdl.handle.net/10948/1317
- Description: The main purpose of this dissertation is to investigate if a teaching method called Focus on Form (FonF) in an English as a Second Language (ESL) class is effective in the acquisition of two grammatical forms namely articles ("a", "an" and "the") and a selection of pronouns. In order to test this hypothesis, quantitative research was performed. The analysis of a series of tests was done quantitatively to prove the hypothesis. The dissertation includes a theory section on Social Capital (SC) and discusses why it might play an important part in South Africa and in offering some help to the communities to enable them to help in the education of their children within South Africa. This dissertation is divided into five chapters. The first chapter introduces the problem and explains how South African education, historically, had devastating effects in the past and continues having a far reaching effect on today‟s learners. It discusses why this dissertation focuses on English and highlights how extensively English has spread throughout the world. It contains an explanation of the value of being competent in the English language. The chapter continues with a depiction of the poor pass rates of the end of year high school examinations, The National Senior Certificate (NSC). It explains the significance of the research, the purpose of the study, its theoretical framework and finally what this study proposes. Chapter two is a literature review of the available literature discussing second language acquisition (SLA) and the difference between English as a Foreign Language (EFL) and English as a Second Language (ESL). The chapter continues with a detailed description of how English was taught historically with an explanation of the approach being used in this study. Chapter two continues with details of the historical "Bantu Education Act No 47 of 1953" and the racist policies of the government of the time with an exploration of the effect these policies had on the education of learners. It also specifies the grammatical forms being used in this study. A summary of Black South African English (BSAE) is included accompanied by a description of language transfer. The chapter contains a section on SC, with an explanation of how this term came about historically and what it means. The chapter includes social problems that South Africa is facing today and how these problems tie in with diminished SC. It explains the importance of SC in Education. The chapter concludes with an explanation of how SC can be utilized in communities and why it is important in a democratic country. Chapter three explains the methodology used in this study as that of positivism and that this study in one sense is purely an empirical study and the reasons behind the choice of methodology. It also explains how a section of this study is pragmatic. Although the testing and analysis is purely statistical, the lessons that took place in the classroom, the interpersonal communication combined with the interaction between the learners and the researcher was not quantitative in nature. This interaction had no outright bearing on the results, but allowed the researcher the opportunity to observe and take notes on the experiences of the learners and the researcher in the classroom. These observations included incidents within the lessons and external problems the learners face which are linked to social issues within the literature. The chapter also contains an explanation of the testing instruments used in this study and how they were developed along with the ethical considerations of the study. Chapter four details the statistical results of this study. It also contains the write up of the field notes of the researcher who took note of incidents that happened within the classes. There are some examples of family and personal problems related to the learners and details the environment of the school. Some of these issues tie in with the theory included; illustrating the ideas and concerns associated with SC and demonstrates how these social problems are truly part of each learner‟s life in a township school. Chapter five offers recommendations to English teachers, the Department of Education (DoE) and to future researchers based on the results of Chapter four. It contains a discussion on how the community can increase SC within their own areas and within the schools. This study argues that the Education system is in dire need of help as evidenced by the dismal exam results. It also argues that South Africa has a variety of social problems that are contributing to the overall failure and dropout rate in schools. It offers some general suggestions on how the community can work together to build systems within the community, to help themselves and their children to become educated, productive members of society. The only way for the children of South Africa to succeed is with a good education as their starting point.
- Full Text:
- Date Issued: 2010
- Authors: White, Emma Lindsey
- Date: 2010
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:8362 , http://hdl.handle.net/10948/1317
- Description: The main purpose of this dissertation is to investigate if a teaching method called Focus on Form (FonF) in an English as a Second Language (ESL) class is effective in the acquisition of two grammatical forms namely articles ("a", "an" and "the") and a selection of pronouns. In order to test this hypothesis, quantitative research was performed. The analysis of a series of tests was done quantitatively to prove the hypothesis. The dissertation includes a theory section on Social Capital (SC) and discusses why it might play an important part in South Africa and in offering some help to the communities to enable them to help in the education of their children within South Africa. This dissertation is divided into five chapters. The first chapter introduces the problem and explains how South African education, historically, had devastating effects in the past and continues having a far reaching effect on today‟s learners. It discusses why this dissertation focuses on English and highlights how extensively English has spread throughout the world. It contains an explanation of the value of being competent in the English language. The chapter continues with a depiction of the poor pass rates of the end of year high school examinations, The National Senior Certificate (NSC). It explains the significance of the research, the purpose of the study, its theoretical framework and finally what this study proposes. Chapter two is a literature review of the available literature discussing second language acquisition (SLA) and the difference between English as a Foreign Language (EFL) and English as a Second Language (ESL). The chapter continues with a detailed description of how English was taught historically with an explanation of the approach being used in this study. Chapter two continues with details of the historical "Bantu Education Act No 47 of 1953" and the racist policies of the government of the time with an exploration of the effect these policies had on the education of learners. It also specifies the grammatical forms being used in this study. A summary of Black South African English (BSAE) is included accompanied by a description of language transfer. The chapter contains a section on SC, with an explanation of how this term came about historically and what it means. The chapter includes social problems that South Africa is facing today and how these problems tie in with diminished SC. It explains the importance of SC in Education. The chapter concludes with an explanation of how SC can be utilized in communities and why it is important in a democratic country. Chapter three explains the methodology used in this study as that of positivism and that this study in one sense is purely an empirical study and the reasons behind the choice of methodology. It also explains how a section of this study is pragmatic. Although the testing and analysis is purely statistical, the lessons that took place in the classroom, the interpersonal communication combined with the interaction between the learners and the researcher was not quantitative in nature. This interaction had no outright bearing on the results, but allowed the researcher the opportunity to observe and take notes on the experiences of the learners and the researcher in the classroom. These observations included incidents within the lessons and external problems the learners face which are linked to social issues within the literature. The chapter also contains an explanation of the testing instruments used in this study and how they were developed along with the ethical considerations of the study. Chapter four details the statistical results of this study. It also contains the write up of the field notes of the researcher who took note of incidents that happened within the classes. There are some examples of family and personal problems related to the learners and details the environment of the school. Some of these issues tie in with the theory included; illustrating the ideas and concerns associated with SC and demonstrates how these social problems are truly part of each learner‟s life in a township school. Chapter five offers recommendations to English teachers, the Department of Education (DoE) and to future researchers based on the results of Chapter four. It contains a discussion on how the community can increase SC within their own areas and within the schools. This study argues that the Education system is in dire need of help as evidenced by the dismal exam results. It also argues that South Africa has a variety of social problems that are contributing to the overall failure and dropout rate in schools. It offers some general suggestions on how the community can work together to build systems within the community, to help themselves and their children to become educated, productive members of society. The only way for the children of South Africa to succeed is with a good education as their starting point.
- Full Text:
- Date Issued: 2010
Justice through language : a critical analysis of the use of foreign African interpreters in South African courtrooms
- Authors: Usadolo, Sam Erevbenagie
- Date: 2010
- Subjects: Translators
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8363 , http://hdl.handle.net/10948/1503 , Translators
- Description: This study represents an analysis of the use of foreign African interpreters in South African courtrooms in the context of the necessity of court interpreting as a vehicle through which accused persons can express themselves in defence of their rights, which may have been violated. As a background to the study, due consideration is given to the history of interpreting, followed by some theoretical perspectives of interpreting, where the differences between translation and interpreting are explained. The discussion of some of the theoretical issues of interpreting also focuses on the notion of equivalence, and the divergent views of scholars regarding this notion, which range from formal equivalence (a source-language oriented approach), through dynamic equivalence (in terms of which translation/interpreting must be in agreement with the form and cultural expectations of the receptor language community) to skopos theory (functional in approach and target text oriented). In discussing the role of the court interpreter, the role boundaries with regard to his/her professional relationship with other participants in the courtroom are highlighted. A related topic, namely that of quality in interpreting, is investigated in relation to quality control by professional associations in different countries, who act as regulatory authorities in this regard. A review of court interpreting in South Africa and selected countries in Africa and the EU, such as Nigeria, Benin, Kenya, Zimbabwe, Namibia, Mozambique and Portugal reveals that efforts to develop court interpreting in some Africa and EU countries are either non-existent or at an incipient stage of development. While South Africa, compared to other countries in Africa, is making progress, she is far behind EU countries such as the UK, France and Spain –all of which possess accreditation systems, professional associations and registers of court interpreters. An analysis of the data collected on foreign African court interpreters shows that, although they work in the same courtrooms as their South African counterparts on a daily basis, they are treated differently in terms of employment procedures, training, remuneration, and such like. The study points out that some factors such as (a) the lack of adequate crosscultural awareness and (b) of a balanced proficiency in their language pair, as well as (c) and the existence of divergent dialects in those languages may pose a challenge to foreign African court interpreters in interpreting cross-border languages and in performing sight translations. The study further reveals that foreign African court interpreters are in serious breach of the professional code of conduct, as exemplified by instances of conflict of interest and partiality in their practices. As regards the management of court interpreters, the findings indicate a general laxity on the side of management, as a result of which there is a lack, inter alia, of an appropriate evaluation or monitoring strategy aimed at detecting such cases of conflict of interest and partiality.
- Full Text:
- Date Issued: 2010
- Authors: Usadolo, Sam Erevbenagie
- Date: 2010
- Subjects: Translators
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8363 , http://hdl.handle.net/10948/1503 , Translators
- Description: This study represents an analysis of the use of foreign African interpreters in South African courtrooms in the context of the necessity of court interpreting as a vehicle through which accused persons can express themselves in defence of their rights, which may have been violated. As a background to the study, due consideration is given to the history of interpreting, followed by some theoretical perspectives of interpreting, where the differences between translation and interpreting are explained. The discussion of some of the theoretical issues of interpreting also focuses on the notion of equivalence, and the divergent views of scholars regarding this notion, which range from formal equivalence (a source-language oriented approach), through dynamic equivalence (in terms of which translation/interpreting must be in agreement with the form and cultural expectations of the receptor language community) to skopos theory (functional in approach and target text oriented). In discussing the role of the court interpreter, the role boundaries with regard to his/her professional relationship with other participants in the courtroom are highlighted. A related topic, namely that of quality in interpreting, is investigated in relation to quality control by professional associations in different countries, who act as regulatory authorities in this regard. A review of court interpreting in South Africa and selected countries in Africa and the EU, such as Nigeria, Benin, Kenya, Zimbabwe, Namibia, Mozambique and Portugal reveals that efforts to develop court interpreting in some Africa and EU countries are either non-existent or at an incipient stage of development. While South Africa, compared to other countries in Africa, is making progress, she is far behind EU countries such as the UK, France and Spain –all of which possess accreditation systems, professional associations and registers of court interpreters. An analysis of the data collected on foreign African court interpreters shows that, although they work in the same courtrooms as their South African counterparts on a daily basis, they are treated differently in terms of employment procedures, training, remuneration, and such like. The study points out that some factors such as (a) the lack of adequate crosscultural awareness and (b) of a balanced proficiency in their language pair, as well as (c) and the existence of divergent dialects in those languages may pose a challenge to foreign African court interpreters in interpreting cross-border languages and in performing sight translations. The study further reveals that foreign African court interpreters are in serious breach of the professional code of conduct, as exemplified by instances of conflict of interest and partiality in their practices. As regards the management of court interpreters, the findings indicate a general laxity on the side of management, as a result of which there is a lack, inter alia, of an appropriate evaluation or monitoring strategy aimed at detecting such cases of conflict of interest and partiality.
- Full Text:
- Date Issued: 2010
Laser surface hardening of AISI 1518 alloy steel
- Authors: Zhang, Tao
- Date: 2010
- Subjects: Lasers , Laser beams , Lasers in engineering , Nd-YAG lasers , Steel alloys , Surfaces -- Effect of radiation on
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9613 , http://hdl.handle.net/10948/723 , Lasers , Laser beams , Lasers in engineering , Nd-YAG lasers , Steel alloys , Surfaces -- Effect of radiation on
- Description: The laser surface hardening process will enhance the hardness profile of automotive components and ensure better process control and predictability of quality as compared to the conventional hardening processes. A 2KW Nd-YAG laser system was used to harden the surface of alloy steel with various process parameters (laser power, focal spot diameter and beam velocity). The results (microhardness, microstructure change and residual stress distribution) were measured and analyzed with Vickers microhardness tester, optical/electron microscope and hole-drilling residual stress equipment. Statistical analyses of the experimental data were used for explaining the relationships between process parameters, microhardness and microstructure. General thermal hardening was applied in the research to show the influence of heating temperature and cooling method on microstructure and mechanical properties. Also, the results were compared with laser surface hardening process from microhardness, microstructure and residual stress to show the advantage of laser surface hardening. Through analysis of the results of the laser surface hardening experiments, a suitable laser power density and interaction time for optimum hardening was obtained. The presented laser surface hardening process can also be applied to other alloy steel surface hardening process.
- Full Text:
- Date Issued: 2010
- Authors: Zhang, Tao
- Date: 2010
- Subjects: Lasers , Laser beams , Lasers in engineering , Nd-YAG lasers , Steel alloys , Surfaces -- Effect of radiation on
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9613 , http://hdl.handle.net/10948/723 , Lasers , Laser beams , Lasers in engineering , Nd-YAG lasers , Steel alloys , Surfaces -- Effect of radiation on
- Description: The laser surface hardening process will enhance the hardness profile of automotive components and ensure better process control and predictability of quality as compared to the conventional hardening processes. A 2KW Nd-YAG laser system was used to harden the surface of alloy steel with various process parameters (laser power, focal spot diameter and beam velocity). The results (microhardness, microstructure change and residual stress distribution) were measured and analyzed with Vickers microhardness tester, optical/electron microscope and hole-drilling residual stress equipment. Statistical analyses of the experimental data were used for explaining the relationships between process parameters, microhardness and microstructure. General thermal hardening was applied in the research to show the influence of heating temperature and cooling method on microstructure and mechanical properties. Also, the results were compared with laser surface hardening process from microhardness, microstructure and residual stress to show the advantage of laser surface hardening. Through analysis of the results of the laser surface hardening experiments, a suitable laser power density and interaction time for optimum hardening was obtained. The presented laser surface hardening process can also be applied to other alloy steel surface hardening process.
- Full Text:
- Date Issued: 2010
Leonotis leonurus: the anticoagulant and antidiabetic activity of Leonotis leonurus
- Authors: Mnonopi, Nandipha
- Date: 2010
- Subjects: Medicinal plants -- South Africa , Materia medica, Vegetable -- South Africa , Diabetes -- Alternative treatment -- South Africa , Plant bioactive compounds , Leonotis leonurus -- Physiological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10323 , http://hdl.handle.net/10948/1194 , Medicinal plants -- South Africa , Materia medica, Vegetable -- South Africa , Diabetes -- Alternative treatment -- South Africa , Plant bioactive compounds , Leonotis leonurus -- Physiological aspects
- Description: Commercial marrubiin, aqueous and organic extracts of Leonotis leonurus were tested in vitro for their anticoagulant and antiplatelet activities. The aqueous extract inhibited platelet aggregation by 69.5 percent (100 μg/mL), while the organic extract (100 μg/mL) and marrubiin (5 μg/mL) showed 92.5 percent and 91.6 percent inhibition, respectively, by inhibiting the binding of fibrinogen to glycoprotein IIb/IIIa receptor in a concentration dependent manner. The extracts significantly prolonged activated partial thromboplastin time compared to untreated plasma controls. Fibrin and D-Dimer formation were drastically decreased. The extracts and marrubiin concentration-dependently inhibited calcium mobilization induced by collagen and thrombin. The formation of thromboxane A2 was also significantly reduced by both the extracts and marrubiin. Protein secretion and platelet adhesion were significantly reduced by both the extracts and marrubiin. The organic extract and marrubiin showed a more pronounced effect than the aqueous extracts in all the in vitro assays. The ex-vivo animal model confirmed the results obtained in vitro. Similar to the in vitro studies, activated partial thromboplastin time clotting time was prolonged by marrubiin and the number of aggregated platelets were significantly reduced relative to aspirin. The findings reflect that marrubiin largely contributes to the organic extract's anticoagulant and antiplatelet effect in vitro. INS-1 cells were cultured under normo- and hyperglycaemic conditions. Marrubiin and the two Leonotis leonurus extracts were screened for anti-diabetic activity in vitro. The stimulatory index of INS-1 cells cultured under hyperglycaemic conditions was significantly increased by 60 percent and 61 percent (p<0.01; n=5) in cells exposed to the organic extract (10 μg/mL) and marrubiin (500 ng/mL), respectively, relative to the normoglycaemic conditions. The gene expression of insulin was significantly increased by 76.5 and 71 percent, and of glucose transporter-2 by 93 and 92.5 percent for marrubiin and the organic extract, respectively, under the same conditions stipulated above (p<0.01; n=4). The extract and marrubiin similarly showed an increase in respiratory rate under hyperglycaemic conditions. Marrubiin increased insulin secretion, HDL-cholesterol, while it decreased total cholesterol, LDL-cholesterol and the atherogenic index in the in vivo rat model.
- Full Text:
- Date Issued: 2010
- Authors: Mnonopi, Nandipha
- Date: 2010
- Subjects: Medicinal plants -- South Africa , Materia medica, Vegetable -- South Africa , Diabetes -- Alternative treatment -- South Africa , Plant bioactive compounds , Leonotis leonurus -- Physiological aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10323 , http://hdl.handle.net/10948/1194 , Medicinal plants -- South Africa , Materia medica, Vegetable -- South Africa , Diabetes -- Alternative treatment -- South Africa , Plant bioactive compounds , Leonotis leonurus -- Physiological aspects
- Description: Commercial marrubiin, aqueous and organic extracts of Leonotis leonurus were tested in vitro for their anticoagulant and antiplatelet activities. The aqueous extract inhibited platelet aggregation by 69.5 percent (100 μg/mL), while the organic extract (100 μg/mL) and marrubiin (5 μg/mL) showed 92.5 percent and 91.6 percent inhibition, respectively, by inhibiting the binding of fibrinogen to glycoprotein IIb/IIIa receptor in a concentration dependent manner. The extracts significantly prolonged activated partial thromboplastin time compared to untreated plasma controls. Fibrin and D-Dimer formation were drastically decreased. The extracts and marrubiin concentration-dependently inhibited calcium mobilization induced by collagen and thrombin. The formation of thromboxane A2 was also significantly reduced by both the extracts and marrubiin. Protein secretion and platelet adhesion were significantly reduced by both the extracts and marrubiin. The organic extract and marrubiin showed a more pronounced effect than the aqueous extracts in all the in vitro assays. The ex-vivo animal model confirmed the results obtained in vitro. Similar to the in vitro studies, activated partial thromboplastin time clotting time was prolonged by marrubiin and the number of aggregated platelets were significantly reduced relative to aspirin. The findings reflect that marrubiin largely contributes to the organic extract's anticoagulant and antiplatelet effect in vitro. INS-1 cells were cultured under normo- and hyperglycaemic conditions. Marrubiin and the two Leonotis leonurus extracts were screened for anti-diabetic activity in vitro. The stimulatory index of INS-1 cells cultured under hyperglycaemic conditions was significantly increased by 60 percent and 61 percent (p<0.01; n=5) in cells exposed to the organic extract (10 μg/mL) and marrubiin (500 ng/mL), respectively, relative to the normoglycaemic conditions. The gene expression of insulin was significantly increased by 76.5 and 71 percent, and of glucose transporter-2 by 93 and 92.5 percent for marrubiin and the organic extract, respectively, under the same conditions stipulated above (p<0.01; n=4). The extract and marrubiin similarly showed an increase in respiratory rate under hyperglycaemic conditions. Marrubiin increased insulin secretion, HDL-cholesterol, while it decreased total cholesterol, LDL-cholesterol and the atherogenic index in the in vivo rat model.
- Full Text:
- Date Issued: 2010
Limitations of the land reform in South Africa : an assessment of two farms in the Eastern Cape
- Authors: Tesana, Zola Eric
- Date: 2010
- Subjects: Land reform -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9082 , http://hdl.handle.net/10948/1122 , Land reform -- South Africa -- Eastern Cape
- Description: The government that was voted in, in 1994 initiated and implemented the Land Reform Programme that had three key elements, namely; Land restitution, redistribution and tenure reform. This study was undertaken to examine the limitations that resulted in some of the projects not to succeed. The study took a form of a case study of two farms that were redistributed in 1997 under the Land Redistribution Programme in the Blue Crane Route Municipal area in the Eastern Cape. The findings confirmed a variety of weaknesses that led to the collapse of these farms. Whilst acknowledging that there are some measures that are put in place to address those limitations the, study shows that there is still scope to do more. It is therefore one’s sincere wish that what transpired out of this study will make a positive contribution by providing some elements that can be used as a remedy in advancing the Land Reform Programme.
- Full Text:
- Date Issued: 2010
- Authors: Tesana, Zola Eric
- Date: 2010
- Subjects: Land reform -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9082 , http://hdl.handle.net/10948/1122 , Land reform -- South Africa -- Eastern Cape
- Description: The government that was voted in, in 1994 initiated and implemented the Land Reform Programme that had three key elements, namely; Land restitution, redistribution and tenure reform. This study was undertaken to examine the limitations that resulted in some of the projects not to succeed. The study took a form of a case study of two farms that were redistributed in 1997 under the Land Redistribution Programme in the Blue Crane Route Municipal area in the Eastern Cape. The findings confirmed a variety of weaknesses that led to the collapse of these farms. Whilst acknowledging that there are some measures that are put in place to address those limitations the, study shows that there is still scope to do more. It is therefore one’s sincere wish that what transpired out of this study will make a positive contribution by providing some elements that can be used as a remedy in advancing the Land Reform Programme.
- Full Text:
- Date Issued: 2010
Macrobenthic community structure across an inter- and subtidal gradient in a mangrove estuary
- Authors: Groenewald, Christoff J
- Date: 2010
- Subjects: Mangrove ecology -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa -- Mngazana Estuary , Benthos -- South Africa -- Mngazana Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10695 , http://hdl.handle.net/10948/1240 , Mangrove ecology -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa -- Mngazana Estuary , Benthos -- South Africa -- Mngazana Estuary
- Description: Macrozoobenthic community structure and composition was investigated along a subtidal-intertidal gradient in the Mngazana Estuary. Six transects were sampled between the spring high water mark (HWST) and the bottom of the river channel in the lower estuary. Fifteen replicate samples were collected along each transect using a Van Veen type grab (211 cm2 bite) during each of three sampling sessions. Samples were sieved through a 500 μm mesh bag and the invertebrates stored in bottles for further analysis in the laboratory. Additional grab samples were collected for sediment particle size analysis and organic matter. Physical variables measured at each transect included: salinity, temperature, dissolved oxygen, depth, pH, percentage mud, organic content and turbidity. Sediment compactness was measured at all intertidal transects and additional sediment samples were collected at mid shore and high shore transects for percentage water content analysis. A total of 104 species were recorded along the intertidal-subtidal gradient in the sampling area. Species richness was higher in the subtidal zone compared to the intertidal zone and polychaetes numerically dominated the macrozoobenthic community at most transects, during all three sessions. At high shore transects the community was characterised by having fewer species, consisting mostly of brachyurans, polychaetes and gastropods. Shannon diversity index (H’) was generally higher for subtidal transects (x¯ = 2.3; range: 2.8 to 1) than for intertidal transects (x¯ = 1.4; range: 2.2 to 0.6) indicating that the distribution of individuals among species in the intertidal zone experienced greater variability. Results for Hill’s numbers followed the same trend as Shannon diversity with subtidal communities mostly consisting of abundant species followed by very abundant species. Intertidal communities generally exhibited lower numbers of abundant and very abundant species. Sedimentary characteristics played a major role in structuring benthic communities in comparison to other physico-chemical variables. Organic content and mud content of the substrate were identified as important factors influencing community patterns observed along the subtidal-intertidal gradient. In addition, sediment compactness and water content of the substrate was found to influence intertidal community structure. Subtidal community structure possibly had a greater dependence on seasonal variations in abiotic and/or biotic factors. Cluster dendrograms used in conjunction with MDS ordination mapping revealed that macrozoobenthic communities were generally distinct between high shore intertidal transects iii and subtidal transects. Most species exhibited a broad spatial distribution along the subtidal-intertidal gradient with mid and high shore transects being the exception. Most species also exhibited marked shifts in abundance and this was especially noticeable at the transition between the subtidal and intertidal zone. Two polychaete species, Prionospio sexoculata and Capitella capitata, were very abundant species and featured amongst the most numerically dominant species collected during each sampling session.
- Full Text:
- Date Issued: 2010
- Authors: Groenewald, Christoff J
- Date: 2010
- Subjects: Mangrove ecology -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa -- Mngazana Estuary , Benthos -- South Africa -- Mngazana Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10695 , http://hdl.handle.net/10948/1240 , Mangrove ecology -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa -- Mngazana Estuary , Benthos -- South Africa -- Mngazana Estuary
- Description: Macrozoobenthic community structure and composition was investigated along a subtidal-intertidal gradient in the Mngazana Estuary. Six transects were sampled between the spring high water mark (HWST) and the bottom of the river channel in the lower estuary. Fifteen replicate samples were collected along each transect using a Van Veen type grab (211 cm2 bite) during each of three sampling sessions. Samples were sieved through a 500 μm mesh bag and the invertebrates stored in bottles for further analysis in the laboratory. Additional grab samples were collected for sediment particle size analysis and organic matter. Physical variables measured at each transect included: salinity, temperature, dissolved oxygen, depth, pH, percentage mud, organic content and turbidity. Sediment compactness was measured at all intertidal transects and additional sediment samples were collected at mid shore and high shore transects for percentage water content analysis. A total of 104 species were recorded along the intertidal-subtidal gradient in the sampling area. Species richness was higher in the subtidal zone compared to the intertidal zone and polychaetes numerically dominated the macrozoobenthic community at most transects, during all three sessions. At high shore transects the community was characterised by having fewer species, consisting mostly of brachyurans, polychaetes and gastropods. Shannon diversity index (H’) was generally higher for subtidal transects (x¯ = 2.3; range: 2.8 to 1) than for intertidal transects (x¯ = 1.4; range: 2.2 to 0.6) indicating that the distribution of individuals among species in the intertidal zone experienced greater variability. Results for Hill’s numbers followed the same trend as Shannon diversity with subtidal communities mostly consisting of abundant species followed by very abundant species. Intertidal communities generally exhibited lower numbers of abundant and very abundant species. Sedimentary characteristics played a major role in structuring benthic communities in comparison to other physico-chemical variables. Organic content and mud content of the substrate were identified as important factors influencing community patterns observed along the subtidal-intertidal gradient. In addition, sediment compactness and water content of the substrate was found to influence intertidal community structure. Subtidal community structure possibly had a greater dependence on seasonal variations in abiotic and/or biotic factors. Cluster dendrograms used in conjunction with MDS ordination mapping revealed that macrozoobenthic communities were generally distinct between high shore intertidal transects iii and subtidal transects. Most species exhibited a broad spatial distribution along the subtidal-intertidal gradient with mid and high shore transects being the exception. Most species also exhibited marked shifts in abundance and this was especially noticeable at the transition between the subtidal and intertidal zone. Two polychaete species, Prionospio sexoculata and Capitella capitata, were very abundant species and featured amongst the most numerically dominant species collected during each sampling session.
- Full Text:
- Date Issued: 2010
Macrophyte phenology in a temporarily open/closed Estuary compared with a permanently open Estuary
- Authors: Vromans, Deborah Claire
- Date: 2010
- Subjects: Estuarine ecology -- South Africa -- East Kleinemonde Estuary , Aquatic plants -- South Africa -- East Kleinemonde Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10612 , http://hdl.handle.net/10948/1393 , Estuarine ecology -- South Africa -- East Kleinemonde Estuary , Aquatic plants -- South Africa -- East Kleinemonde Estuary
- Description: Temporarily open/closed estuaries (TOCEs) are unpredictable environments that change in response to mouth condition, which is influenced by freshwater flooding or sea storm surges. The aim of the study was to determine whether macrophyte phenology in a TOCE was event driven rather than cyclically predictable and if it differed from permanently open estuaries (POEs). Macrophyte growth and flowering phenology in response to environmental conditions was investigated in the East Kleinemonde Estuary (TOCE) and the Kowie Estuary (POE) along the eastern coastline of South Africa. The lack of freshwater flooding due to low rainfall coupled with several overwash events resulted in a prolonged period of mouth closure from September 2008 to the end of this study period in 2010. This in turn caused the inundation of the supratidal and intertidal habitats, high water level (> 1.57 m amsl) and high salinity (30 - 42 ppt) in the TOCE. Principle Components Analysis showed that high water level and reduced sediments were the most significant environmental factors affecting macrophyte phenology. Macrophyte phenology in the POE was primarily driven by temperature, sediment redox potential and salinity. The saline high water level and reduced sediment significantly reduced macrophyte cover in all habitats in the TOCE. Macrophytes in the POE maintained high cover abundance due to seasonal re-growth compared to the TOCE where cover declined over the sampling period due to the high water level. Subsequent to water level dropping by as little as 11 - 20 cm in the TOCE, the intertidal species Sarcocornia tegetaria and Salicornia meyeriana completed their life-cycles and produced viable seeds within four and three months of germinating respectively. In contrast, the Sarcocornia hybrid and S. meyeriana in the POE took longer to complete their life-cycles, namely seven and nine months respectively, while S. tegataria did not germinate in situ but reproduced vegetatively despite producing seed. In the TOCE, the submerged species Ruppia cirrhosa and Chara vulgaris completed their life-cycles within five and three months and produced a maximum of 26 242 and 196 998 seeds m-2 respectively. Due to high water level and prolonged inundation, the reproductive periods were shorter for the intertidal and reed and sedge species in the TOCE compared to the POE. Seed output during the two reproduction periods varied between the two estuaries. Sarcocornia decumbens and S. tegetaria produced a substantially higher number of seeds in the TOCE compared to the POE, namely 0 - 102 847 versus 20 661 - 48 576 seeds m-²; and 7 001 - 45 542 versus 1 587 – 16 958 seeds m-² respectively. Seed output in the TOCE was significantly higher in S. tegetaria during the second reproduction period despite the significantly lower plant cover, which may be a function of the stressful environment in the TOCE. Seed production of S. meyeriana was significantly higher in the POE compared to the TOCE, with 264 224 - 640 292 compared with 24 050 - 27 643 seeds m-², due to higher plant cover in the POE. The research suggests that macrophyte phenology in the TOCE was significantly influenced by mouth condition. Further, macrophytes were able to demonstrate considerable phenotypic plasticity in response to changing and unfavourable environmental conditions. These data can be used in mouth management plans and freshwater requirement studies in TOCEs to ensure that macrophytes can complete their life-cycles and produce viable seeds for the safeguarding of habitat persistence and ecological processes. In impacted estuaries where artificial mouth opening is practised and the macrophytes have been severely degraded or extirpated, management should ensure that the intertidal and supratidal habitats are not inundated during peak flowering and seed production periods i.e. late spring to early autumn (November to March).
- Full Text:
- Date Issued: 2010
- Authors: Vromans, Deborah Claire
- Date: 2010
- Subjects: Estuarine ecology -- South Africa -- East Kleinemonde Estuary , Aquatic plants -- South Africa -- East Kleinemonde Estuary
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10612 , http://hdl.handle.net/10948/1393 , Estuarine ecology -- South Africa -- East Kleinemonde Estuary , Aquatic plants -- South Africa -- East Kleinemonde Estuary
- Description: Temporarily open/closed estuaries (TOCEs) are unpredictable environments that change in response to mouth condition, which is influenced by freshwater flooding or sea storm surges. The aim of the study was to determine whether macrophyte phenology in a TOCE was event driven rather than cyclically predictable and if it differed from permanently open estuaries (POEs). Macrophyte growth and flowering phenology in response to environmental conditions was investigated in the East Kleinemonde Estuary (TOCE) and the Kowie Estuary (POE) along the eastern coastline of South Africa. The lack of freshwater flooding due to low rainfall coupled with several overwash events resulted in a prolonged period of mouth closure from September 2008 to the end of this study period in 2010. This in turn caused the inundation of the supratidal and intertidal habitats, high water level (> 1.57 m amsl) and high salinity (30 - 42 ppt) in the TOCE. Principle Components Analysis showed that high water level and reduced sediments were the most significant environmental factors affecting macrophyte phenology. Macrophyte phenology in the POE was primarily driven by temperature, sediment redox potential and salinity. The saline high water level and reduced sediment significantly reduced macrophyte cover in all habitats in the TOCE. Macrophytes in the POE maintained high cover abundance due to seasonal re-growth compared to the TOCE where cover declined over the sampling period due to the high water level. Subsequent to water level dropping by as little as 11 - 20 cm in the TOCE, the intertidal species Sarcocornia tegetaria and Salicornia meyeriana completed their life-cycles and produced viable seeds within four and three months of germinating respectively. In contrast, the Sarcocornia hybrid and S. meyeriana in the POE took longer to complete their life-cycles, namely seven and nine months respectively, while S. tegataria did not germinate in situ but reproduced vegetatively despite producing seed. In the TOCE, the submerged species Ruppia cirrhosa and Chara vulgaris completed their life-cycles within five and three months and produced a maximum of 26 242 and 196 998 seeds m-2 respectively. Due to high water level and prolonged inundation, the reproductive periods were shorter for the intertidal and reed and sedge species in the TOCE compared to the POE. Seed output during the two reproduction periods varied between the two estuaries. Sarcocornia decumbens and S. tegetaria produced a substantially higher number of seeds in the TOCE compared to the POE, namely 0 - 102 847 versus 20 661 - 48 576 seeds m-²; and 7 001 - 45 542 versus 1 587 – 16 958 seeds m-² respectively. Seed output in the TOCE was significantly higher in S. tegetaria during the second reproduction period despite the significantly lower plant cover, which may be a function of the stressful environment in the TOCE. Seed production of S. meyeriana was significantly higher in the POE compared to the TOCE, with 264 224 - 640 292 compared with 24 050 - 27 643 seeds m-², due to higher plant cover in the POE. The research suggests that macrophyte phenology in the TOCE was significantly influenced by mouth condition. Further, macrophytes were able to demonstrate considerable phenotypic plasticity in response to changing and unfavourable environmental conditions. These data can be used in mouth management plans and freshwater requirement studies in TOCEs to ensure that macrophytes can complete their life-cycles and produce viable seeds for the safeguarding of habitat persistence and ecological processes. In impacted estuaries where artificial mouth opening is practised and the macrophytes have been severely degraded or extirpated, management should ensure that the intertidal and supratidal habitats are not inundated during peak flowering and seed production periods i.e. late spring to early autumn (November to March).
- Full Text:
- Date Issued: 2010
Managerial decision making processes and affective outcomes as a function of individual factors and self-efficacy beliefs
- Authors: Myburgh, Wim
- Date: 2010
- Subjects: Decision making
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9893 , http://hdl.handle.net/10948/1141 , Decision making
- Description: Making decisions in the business environment is arguably the most challenging aspect of managers' yet also the easiest to fail in. Unlike individual decisions managers as agents for their organizations make decisions amidst high levels of ambiguity, incomplete information and mostly under time pressure. These are the very conditions that make managers vulnerable to the volition-undermining potential of decision-generated affect precisely when they are feeling over-extended to deal with such demands. Effective managerial decision making (MDM) involves more than applying a set of individual abilities. Managers face numerous obstacles, failures, and setbacks that often carry perturbing self-evaluative implications as well as social consequences that undermine their self-evaluations in ways that impair good use of their decision making skills (Bandura, 1997). Given the absence of a coherent theoretical framework in the literature the conceptual model of relations put forward attempts to organize and simplify how managers make decisions as agents of their organizations. Most conceptualizations apply oversimplified models that focus attention on one or a few variables, neglect the joint constellations of individual variable factors and the influence of individual self-generated influences as a contributing factor in MDM. As an ex post facto explanatory-predictive study the present research offers evidence of these links among the theoretically relevant constructs in order to formulate an account of their relations in a parsimonious framework that could guide future insights to explain and predict the intentions and direction of managerial decision behaviour. Conceptual research has outpaced empirical research in decision making of managers in organizations. A number of mini-theories exists that focus on a few variables using linear, antecedent-consequence relations with manipulations in laboratory environments that deal with decisions in contexts that are very different to those faced by managers. There is limited research on managers as research participants and empirical findings based on non-managerial samples and students may not generalize to managers in real life decision making. The present research used a non-probability, purposive sample (N = 196) of experienced managers in the Western Cape region of South Africa, all employed in private and public organizations (mean age 38.9 years, SD of 7.49, ethnic black managers constituted 15.8 percent of the sample). As part of the study it was necessary to construct and validate custom indicator measures in an independent pilot study from the same population. The pilot study determined the factor structures of the dimensionality and internal consistency of the custom-designed measures by way of both convergent, as well as, discriminative validity. The exploratory factor (EFA) and internal reliability analyses succeeded to provide both a comprehensive and empirical grasp on the constructs as was defined. Further, analyses of both standardized and custom-designed also revealed no significant difference between black and other managers across the pilot samples which provided confidence of the substantive relations of interest (i.e., the associations among the variables). Structural equation modeling (SEM) was chosen as the data analysis strategy of choice and a confirmatory factor analysis (CFA) demonstrated that the operational measures by and large succeeded in providing both a comprehensive and empirical grasp on the constructs as defined. The inter-construct relations were also consistent with expectations. Evidence for convergent validity however proved that the indicator measures for the allocation of attentional resources were less than adequate in order to provide an uncontaminated measure as a latent variable. The structural model was subjected to further scrutiny by way of a spectrum of goodness-of-fit statistics. The analyses revealed that the model was not adequate and the null hypothesis that the model fitted the population data was subsequently, rejected. It was also sensible to assess the degree of lack of fit of the model with reference to RMSEA which revealed a value of .08, that suggested a reasonable model fit. The poor structural model fit could however be attributed to the failure of the measured indicators used to provide an acceptable grasp of the allocation of attentional resources as a latent variable. The inherent structural flaws in the model could however not be unequivocally be ruled out as an additional possibility of poor fit. One conclusion is the possibility of an expanded model that requires additional indicator measures and additional paths. Notwithstanding these limitations, the present research provided support for social cognitive theory that underlies the model. In accordance with the literature and empirical findings the present research demonstrated mangers' decision making is much more than reason-based behaviour. The present research demonstrates the interdependencies and cumulative effects among individual factors, self-efficacy beliefs and temporal volitional processes, as psychological iv mechanisms through which social-structural factors are linked to the quality of MDM processes. The present research also presents an argument for the independent contributions of self-efficacy beliefs as causal influences on "hot temporal processes" that promote accuracy in decision making. Although present research demonstrates that the estimates were greater for cognitive ability than for both self-efficacy beliefs and social self-confidence it does not suggest that personality traits and self-efficacy beliefs have no utility. The present research demonstrates that cognitive ability combines with personality traits, self-efficacy beliefs and temporal processes (decision-generated affect and the allocation of attentional resources) in a complex manner through multiple pathways.
- Full Text:
- Date Issued: 2010
- Authors: Myburgh, Wim
- Date: 2010
- Subjects: Decision making
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9893 , http://hdl.handle.net/10948/1141 , Decision making
- Description: Making decisions in the business environment is arguably the most challenging aspect of managers' yet also the easiest to fail in. Unlike individual decisions managers as agents for their organizations make decisions amidst high levels of ambiguity, incomplete information and mostly under time pressure. These are the very conditions that make managers vulnerable to the volition-undermining potential of decision-generated affect precisely when they are feeling over-extended to deal with such demands. Effective managerial decision making (MDM) involves more than applying a set of individual abilities. Managers face numerous obstacles, failures, and setbacks that often carry perturbing self-evaluative implications as well as social consequences that undermine their self-evaluations in ways that impair good use of their decision making skills (Bandura, 1997). Given the absence of a coherent theoretical framework in the literature the conceptual model of relations put forward attempts to organize and simplify how managers make decisions as agents of their organizations. Most conceptualizations apply oversimplified models that focus attention on one or a few variables, neglect the joint constellations of individual variable factors and the influence of individual self-generated influences as a contributing factor in MDM. As an ex post facto explanatory-predictive study the present research offers evidence of these links among the theoretically relevant constructs in order to formulate an account of their relations in a parsimonious framework that could guide future insights to explain and predict the intentions and direction of managerial decision behaviour. Conceptual research has outpaced empirical research in decision making of managers in organizations. A number of mini-theories exists that focus on a few variables using linear, antecedent-consequence relations with manipulations in laboratory environments that deal with decisions in contexts that are very different to those faced by managers. There is limited research on managers as research participants and empirical findings based on non-managerial samples and students may not generalize to managers in real life decision making. The present research used a non-probability, purposive sample (N = 196) of experienced managers in the Western Cape region of South Africa, all employed in private and public organizations (mean age 38.9 years, SD of 7.49, ethnic black managers constituted 15.8 percent of the sample). As part of the study it was necessary to construct and validate custom indicator measures in an independent pilot study from the same population. The pilot study determined the factor structures of the dimensionality and internal consistency of the custom-designed measures by way of both convergent, as well as, discriminative validity. The exploratory factor (EFA) and internal reliability analyses succeeded to provide both a comprehensive and empirical grasp on the constructs as was defined. Further, analyses of both standardized and custom-designed also revealed no significant difference between black and other managers across the pilot samples which provided confidence of the substantive relations of interest (i.e., the associations among the variables). Structural equation modeling (SEM) was chosen as the data analysis strategy of choice and a confirmatory factor analysis (CFA) demonstrated that the operational measures by and large succeeded in providing both a comprehensive and empirical grasp on the constructs as defined. The inter-construct relations were also consistent with expectations. Evidence for convergent validity however proved that the indicator measures for the allocation of attentional resources were less than adequate in order to provide an uncontaminated measure as a latent variable. The structural model was subjected to further scrutiny by way of a spectrum of goodness-of-fit statistics. The analyses revealed that the model was not adequate and the null hypothesis that the model fitted the population data was subsequently, rejected. It was also sensible to assess the degree of lack of fit of the model with reference to RMSEA which revealed a value of .08, that suggested a reasonable model fit. The poor structural model fit could however be attributed to the failure of the measured indicators used to provide an acceptable grasp of the allocation of attentional resources as a latent variable. The inherent structural flaws in the model could however not be unequivocally be ruled out as an additional possibility of poor fit. One conclusion is the possibility of an expanded model that requires additional indicator measures and additional paths. Notwithstanding these limitations, the present research provided support for social cognitive theory that underlies the model. In accordance with the literature and empirical findings the present research demonstrated mangers' decision making is much more than reason-based behaviour. The present research demonstrates the interdependencies and cumulative effects among individual factors, self-efficacy beliefs and temporal volitional processes, as psychological iv mechanisms through which social-structural factors are linked to the quality of MDM processes. The present research also presents an argument for the independent contributions of self-efficacy beliefs as causal influences on "hot temporal processes" that promote accuracy in decision making. Although present research demonstrates that the estimates were greater for cognitive ability than for both self-efficacy beliefs and social self-confidence it does not suggest that personality traits and self-efficacy beliefs have no utility. The present research demonstrates that cognitive ability combines with personality traits, self-efficacy beliefs and temporal processes (decision-generated affect and the allocation of attentional resources) in a complex manner through multiple pathways.
- Full Text:
- Date Issued: 2010
Managing the implementation of management structure changes at the Eastern Cape Department of Education
- Authors: Muthige, Shumani Ralson
- Date: 2010
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8534 , http://hdl.handle.net/10948/1652
- Description: The Eastern Cape Department of Education has been in the forefront of the media – mostly for the wrong reasons. The major problems that have been reported range from the mismanagement of the feeding schemes, unpaid service providers, lack of adequate infrastructure, corruption committed by the officials, unfilled posts, poor service delivery and the second lowest matriculation pass rate in the country. Although there are many problems, as stated, this study research is focused on the management of change and its implementation in the organisational structure.
- Full Text:
- Date Issued: 2010
- Authors: Muthige, Shumani Ralson
- Date: 2010
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8534 , http://hdl.handle.net/10948/1652
- Description: The Eastern Cape Department of Education has been in the forefront of the media – mostly for the wrong reasons. The major problems that have been reported range from the mismanagement of the feeding schemes, unpaid service providers, lack of adequate infrastructure, corruption committed by the officials, unfilled posts, poor service delivery and the second lowest matriculation pass rate in the country. Although there are many problems, as stated, this study research is focused on the management of change and its implementation in the organisational structure.
- Full Text:
- Date Issued: 2010
Managing the perceptions about affirmitive action (AA)
- Authors: Swartbooi, Aurick Devlin
- Date: 2010
- Subjects: Affirmative action programs -- South Africa , Affirmative action programs -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8684 , http://hdl.handle.net/10948/1120 , Affirmative action programs -- South Africa , Affirmative action programs -- Law and legislation -- South Africa
- Description: The main research problem focused on the effective management of the perceptions about Affirmative Action (AA). A literature study and a survey were conducted to investigate the extent and nature of perceptions, the effect of these perceptions on labour and personal relations, current and suggested management practice of the perceptions of AA. A definition of AA, earlier measures of AA, the implementation of AA in the South African context, the stages of AA, theories, relevant legislation, perceptions and the management thereof are discussed. The survey was conducted at the George and Beaufort West District offices of the Department of Rural Development and Land Reform (DRDLR) with a response rate of 78.95 percent. The perceptions about AA can be managed effectively by complying with legislation, by involving and making all levels of employees responsible for the achievement of employment equity, skills development, personal development, consultation and communication.
- Full Text:
- Date Issued: 2010
- Authors: Swartbooi, Aurick Devlin
- Date: 2010
- Subjects: Affirmative action programs -- South Africa , Affirmative action programs -- Law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8684 , http://hdl.handle.net/10948/1120 , Affirmative action programs -- South Africa , Affirmative action programs -- Law and legislation -- South Africa
- Description: The main research problem focused on the effective management of the perceptions about Affirmative Action (AA). A literature study and a survey were conducted to investigate the extent and nature of perceptions, the effect of these perceptions on labour and personal relations, current and suggested management practice of the perceptions of AA. A definition of AA, earlier measures of AA, the implementation of AA in the South African context, the stages of AA, theories, relevant legislation, perceptions and the management thereof are discussed. The survey was conducted at the George and Beaufort West District offices of the Department of Rural Development and Land Reform (DRDLR) with a response rate of 78.95 percent. The perceptions about AA can be managed effectively by complying with legislation, by involving and making all levels of employees responsible for the achievement of employment equity, skills development, personal development, consultation and communication.
- Full Text:
- Date Issued: 2010
Meaning in life and sense of coherence in HIV-positive adults
- Authors: Nolte, Coenraad B
- Date: 2010
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9857 , http://hdl.handle.net/10948/1562
- Description: Human Immunodeficiency Virus (HIV) infection is highly prevalent in South Africa and inevitably leads to an acute stage of the disease referred to as Acquired Immunodeficiency Syndrome (AIDS). Individual variations in the rate of HIV-disease progression are, amongst others, a function of the psychological reactions to an HIV-positive diagnosis and the prevalence of psychosocial stressors. This study was conducted in the context of the salutogenic paradigm and the existential psychological theory of Viktor Frankl. Sense of coherence is a key salutogenic concept and previous studies have suggested a positive correlation between the sense of coherence and the wellbeing of HIV-positive individuals. The objectives of this research were to explore and describe the search for meaning in life, the presence of meaning in life, the sense of coherence and the potential relationships among these concepts in HIV-positive adults. The research sample consisted of 62 participants recruited from an HIV wellness clinic in the Nelson Mandela Metropolitan area. Key findings included the following: Levels of search for meaning in life and presence of meaning in life were not found to be elevated or suppressed in the research sample. No significant relationship was found between the levels of search for meaning in life and presence of meaning in life. The level of sense of coherence of the sample was found to be lower than the level of sense of coherence obtained in previous studies from healthy, mixed populations in South Africa. A statistically significant relationship was found between the levels of presence of meaning in life and the sense of coherence. In conclusion it was proposed that presence of meaning in life is a fortifier of the sense of coherence.
- Full Text:
- Date Issued: 2010
- Authors: Nolte, Coenraad B
- Date: 2010
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9857 , http://hdl.handle.net/10948/1562
- Description: Human Immunodeficiency Virus (HIV) infection is highly prevalent in South Africa and inevitably leads to an acute stage of the disease referred to as Acquired Immunodeficiency Syndrome (AIDS). Individual variations in the rate of HIV-disease progression are, amongst others, a function of the psychological reactions to an HIV-positive diagnosis and the prevalence of psychosocial stressors. This study was conducted in the context of the salutogenic paradigm and the existential psychological theory of Viktor Frankl. Sense of coherence is a key salutogenic concept and previous studies have suggested a positive correlation between the sense of coherence and the wellbeing of HIV-positive individuals. The objectives of this research were to explore and describe the search for meaning in life, the presence of meaning in life, the sense of coherence and the potential relationships among these concepts in HIV-positive adults. The research sample consisted of 62 participants recruited from an HIV wellness clinic in the Nelson Mandela Metropolitan area. Key findings included the following: Levels of search for meaning in life and presence of meaning in life were not found to be elevated or suppressed in the research sample. No significant relationship was found between the levels of search for meaning in life and presence of meaning in life. The level of sense of coherence of the sample was found to be lower than the level of sense of coherence obtained in previous studies from healthy, mixed populations in South Africa. A statistically significant relationship was found between the levels of presence of meaning in life and the sense of coherence. In conclusion it was proposed that presence of meaning in life is a fortifier of the sense of coherence.
- Full Text:
- Date Issued: 2010
Media convergence : an analysis of consumer engagement
- Authors: Muwanga-Zake, Semeyi
- Date: 2010
- Subjects: Mass media , Journalism
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8612 , http://hdl.handle.net/10948/1557 , Mass media , Journalism
- Description: Media convergence has meant that the traditional separations between the various media industries, such as the internet, broadcasting and telephone networks are slowly collapsing due to the growing use and influence of digital electronics - in effect, morphing or transforming the media landscape. A fundamental change in today's media landscape has been the shift in control over media content, consumer consumption patterns as well as the manner and level at which consumers interact. Thus, the extent to which success is achieved now depends on a customer centric engagement strategy that can be implemented across converged platforms. This study considers the challenges posed by media convergence. It also investigates how organisations adjusted strategies to mitigate these challenges.
- Full Text:
- Date Issued: 2010
- Authors: Muwanga-Zake, Semeyi
- Date: 2010
- Subjects: Mass media , Journalism
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8612 , http://hdl.handle.net/10948/1557 , Mass media , Journalism
- Description: Media convergence has meant that the traditional separations between the various media industries, such as the internet, broadcasting and telephone networks are slowly collapsing due to the growing use and influence of digital electronics - in effect, morphing or transforming the media landscape. A fundamental change in today's media landscape has been the shift in control over media content, consumer consumption patterns as well as the manner and level at which consumers interact. Thus, the extent to which success is achieved now depends on a customer centric engagement strategy that can be implemented across converged platforms. This study considers the challenges posed by media convergence. It also investigates how organisations adjusted strategies to mitigate these challenges.
- Full Text:
- Date Issued: 2010
Mediating factors in the relationship between childhood sexual abuse and HIV Sexual risk behaviour among men who have sex with men
- Authors: Heusser, Shelly Lucien
- Date: 2010
- Subjects: Adult child sexual abuse victims -- Sexual behavior -- South Africa , Sexually transmitted diseases -- Psychological aspects , Risk-taking (Psychology)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9873 , http://hdl.handle.net/10948/1398 , Adult child sexual abuse victims -- Sexual behavior -- South Africa , Sexually transmitted diseases -- Psychological aspects , Risk-taking (Psychology)
- Description: Previous studies have indicated an association between childhood sexual abuse (CSA) and an increased risk of engaging in unsafe behaviours during adulthood, including risky sexual practices. This study examined the relationship between CSA and adult HIV sexual risk behaviour among a sample of South African men who have sex with men (MSM). Potential pathological long-term mental health outcomes of CSA, including dissociation, sex-related substance abuse, depression, sexual compulsivity, impaired interpersonal communication, and over-reliance on submissive sexual scripts, were treated as variables mediating the relationship between CSA and sexual risk behaviour. Men frequenting a gay internet dating site were randomly selected to complete an electronic version of the anonymous survey. Results indicate that one-fourth of participants reported a history of CSA. Men with a history of unwanted sexual activity during childhood were more likely to report recreational substance abuse, sex-related substance abuse, sexual compulsivity, and adult revictimisation experiences. Men who were abused were also more likely to engage in unprotected anal intercourse compared to those who were not abused. Mediation analyses revealed that MSM who are survivors of CSA are particularly susceptible to drug abuse, sex-related drug abuse, and sexual compulsivity, and these sequelae in turn predict higher reported numbers of male sexual partners. The current data suggest that CSA is widespread among men at high risk for HIV infection, and that it may have a devastating influence on the quality of life and health risk behaviour of these men. These results also highlight the importance of mental health services and new approaches in HIV prevention for MSM who have been sexually abused as children. Further research is needed into the contextual factors of the childhood abuse experience which account for the variability in longterm negative mental health outcomes of CSA survivors.
- Full Text:
- Date Issued: 2010
- Authors: Heusser, Shelly Lucien
- Date: 2010
- Subjects: Adult child sexual abuse victims -- Sexual behavior -- South Africa , Sexually transmitted diseases -- Psychological aspects , Risk-taking (Psychology)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9873 , http://hdl.handle.net/10948/1398 , Adult child sexual abuse victims -- Sexual behavior -- South Africa , Sexually transmitted diseases -- Psychological aspects , Risk-taking (Psychology)
- Description: Previous studies have indicated an association between childhood sexual abuse (CSA) and an increased risk of engaging in unsafe behaviours during adulthood, including risky sexual practices. This study examined the relationship between CSA and adult HIV sexual risk behaviour among a sample of South African men who have sex with men (MSM). Potential pathological long-term mental health outcomes of CSA, including dissociation, sex-related substance abuse, depression, sexual compulsivity, impaired interpersonal communication, and over-reliance on submissive sexual scripts, were treated as variables mediating the relationship between CSA and sexual risk behaviour. Men frequenting a gay internet dating site were randomly selected to complete an electronic version of the anonymous survey. Results indicate that one-fourth of participants reported a history of CSA. Men with a history of unwanted sexual activity during childhood were more likely to report recreational substance abuse, sex-related substance abuse, sexual compulsivity, and adult revictimisation experiences. Men who were abused were also more likely to engage in unprotected anal intercourse compared to those who were not abused. Mediation analyses revealed that MSM who are survivors of CSA are particularly susceptible to drug abuse, sex-related drug abuse, and sexual compulsivity, and these sequelae in turn predict higher reported numbers of male sexual partners. The current data suggest that CSA is widespread among men at high risk for HIV infection, and that it may have a devastating influence on the quality of life and health risk behaviour of these men. These results also highlight the importance of mental health services and new approaches in HIV prevention for MSM who have been sexually abused as children. Further research is needed into the contextual factors of the childhood abuse experience which account for the variability in longterm negative mental health outcomes of CSA survivors.
- Full Text:
- Date Issued: 2010
Mental health care practitioners' perceptions of mental illness within the isiXhosa cultural context
- Authors: Lombo, Nocawa Philomina
- Date: 2010
- Subjects: Mental illness -- South Africa , Mental health personnel , Psychiatric nursing , Xhosa (African people) -- Psychology , Xhosa (African people) -- Social life and customs
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9997 , http://hdl.handle.net/10948/1179 , Mental illness -- South Africa , Mental health personnel , Psychiatric nursing , Xhosa (African people) -- Psychology , Xhosa (African people) -- Social life and customs
- Description: This study sought to explore the perceptions of mental health care practitioners’ perceptions on mental illness within the isiXhosa cultural context. A qualitative exploratory descriptive and contextual design was used for the study. A non-probability purposive sampling method was used to select eight participants from Komani Hospital in Queenstown. Data was collected through semi-structured interviews. The services of an Independent Interviewer were used to avoid any bias as interviews took place where the researcher is employed. All interviews were transcribed verbatim and the data collected was analyzed according to Tesch’s eight steps of data analysis as described in Cresswell (1994:155). The researcher utilized services of an Independent Coder who verified the identified major themes. Four major themes emerged from the analysis of the interview: Mental health care practitioner’s perceptions of mental illness, perception of the causes of mental illness within the isiXhosa cultural context, mental health care practitioners’ views in the management and treatment of mental illness and suggestions put forward to improve the services to mental health care users. The major findings of this study were the lack of knowledge of culture of mental health care users. It is recommended that it would be proper if there could be co-operation between mental health care practitioners and traditional healers by working together as a team.
- Full Text:
- Date Issued: 2010
Mental health care practitioners' perceptions of mental illness within the isiXhosa cultural context
- Authors: Lombo, Nocawa Philomina
- Date: 2010
- Subjects: Mental illness -- South Africa , Mental health personnel , Psychiatric nursing , Xhosa (African people) -- Psychology , Xhosa (African people) -- Social life and customs
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9997 , http://hdl.handle.net/10948/1179 , Mental illness -- South Africa , Mental health personnel , Psychiatric nursing , Xhosa (African people) -- Psychology , Xhosa (African people) -- Social life and customs
- Description: This study sought to explore the perceptions of mental health care practitioners’ perceptions on mental illness within the isiXhosa cultural context. A qualitative exploratory descriptive and contextual design was used for the study. A non-probability purposive sampling method was used to select eight participants from Komani Hospital in Queenstown. Data was collected through semi-structured interviews. The services of an Independent Interviewer were used to avoid any bias as interviews took place where the researcher is employed. All interviews were transcribed verbatim and the data collected was analyzed according to Tesch’s eight steps of data analysis as described in Cresswell (1994:155). The researcher utilized services of an Independent Coder who verified the identified major themes. Four major themes emerged from the analysis of the interview: Mental health care practitioner’s perceptions of mental illness, perception of the causes of mental illness within the isiXhosa cultural context, mental health care practitioners’ views in the management and treatment of mental illness and suggestions put forward to improve the services to mental health care users. The major findings of this study were the lack of knowledge of culture of mental health care users. It is recommended that it would be proper if there could be co-operation between mental health care practitioners and traditional healers by working together as a team.
- Full Text:
- Date Issued: 2010
Metabolic energy relations in the Eastern Cape Angulate Tortoise (Chersina Anguluta)
- Authors: Setlalekgomo, Mpho Rinah
- Date: 2010
- Subjects: Eastern Cape angulate Tortoise , Oxygen consumption (Physiology)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10690 , http://hdl.handle.net/10948/1400 , Eastern Cape angulate Tortoise , Oxygen consumption (Physiology)
- Description: The daily oxygen consumption (VO2) pattern, the effects of varying ambient temperatures, season and mass on the resting oxygen consumption (RVO2) of Chersina angulata of the Eastern Cape were investigated. The RVO2 was measured using flow-through respirometry and specific resting oxygen consumption (sRVO2) calculated. To determine the daily pattern in the VO2 of C. angulata, the tortoises were acclimated in an environmentally controlled room (ECR) to an ambient temperature of 26 ± 1°C and a light regime of 14 hours of light and 10 hours of darkness (14L:10D) for at least a week prior to the RVO2 measurements. The RVO2 was measured at a constant temperature of 26 ± 1°C, and at three different light regimes, namely: 14L:10D, constant darkness (DD) and constant light (LL). There were no significant effects of mass or gender on the sRVO2 of the tortoises used. Rhythms in the sRVO2 were detected under all three light regimes. The amplitudes of the rhythm were largest at 14L:10D, followed by DD and smallest at LL regime. The persistence of the rhythmic pattern under constant conditions suggests the existence of an endogenous circadian rhythm in the sRVO2 for adult C. angulata. To test for the effect of ambient temperature on the sRVO2 of adult C. angulata, the tortoises were acclimated to 22 ± 1°C and a 14L:10D light regime prior to the RVO2 measurements. RVO2 was measured at eight experimental temperatures; 14°C, 18°C, 22°C, 26°C, 30°C, 35°C, 38°C and 40°C. The sRVO2 was not influenced by gender and increased with experimental temperatures, but this did not happen consistently over the whole range of temperatures tested. A plateau, possibly a thermal preferendum zone, was detected within the temperature range of 26 - 38°C. Determination of seasonal effect on the sRVO2 of adult C. angulata was accomplished by acclimating tortoises to standard summer and winter conditions. Seasonal effects were tested in the appropriate seasons. Winter experiments were conducted in winter and summer experiments conducted in summer. The RVO2 was measured at experimental temperature 14°C, 18°C and 22°C. In addition RVO2 of iv winter-acclimated tortoises was also measured at 10°C. The sRVO2 increased significantly with increasing temperature within the temperature range tested. No distinct pattern was observed in the seasonal acclimation of adult C. angulata. The metabolic rate-temperature curves of the summer and the winter-acclimated tortoises cross each other. Season and temperature had no significant effects on the mass-scaling exponent of the sRVO2. The exponent ranged from 0.48 to 0.73 within the temperature range of 22 - 38°C. Below and above this temperature range, the exponent ranged from 1.47 to 1.67. An inverse relationship was observed between sRVO2 and body mass over the temperature range of 22 - 38°C. At 14°C and 18°C, sRVO2 increased with body mass, while at 10°C and at 40°C the slope was 1.01.
- Full Text:
- Date Issued: 2010
- Authors: Setlalekgomo, Mpho Rinah
- Date: 2010
- Subjects: Eastern Cape angulate Tortoise , Oxygen consumption (Physiology)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10690 , http://hdl.handle.net/10948/1400 , Eastern Cape angulate Tortoise , Oxygen consumption (Physiology)
- Description: The daily oxygen consumption (VO2) pattern, the effects of varying ambient temperatures, season and mass on the resting oxygen consumption (RVO2) of Chersina angulata of the Eastern Cape were investigated. The RVO2 was measured using flow-through respirometry and specific resting oxygen consumption (sRVO2) calculated. To determine the daily pattern in the VO2 of C. angulata, the tortoises were acclimated in an environmentally controlled room (ECR) to an ambient temperature of 26 ± 1°C and a light regime of 14 hours of light and 10 hours of darkness (14L:10D) for at least a week prior to the RVO2 measurements. The RVO2 was measured at a constant temperature of 26 ± 1°C, and at three different light regimes, namely: 14L:10D, constant darkness (DD) and constant light (LL). There were no significant effects of mass or gender on the sRVO2 of the tortoises used. Rhythms in the sRVO2 were detected under all three light regimes. The amplitudes of the rhythm were largest at 14L:10D, followed by DD and smallest at LL regime. The persistence of the rhythmic pattern under constant conditions suggests the existence of an endogenous circadian rhythm in the sRVO2 for adult C. angulata. To test for the effect of ambient temperature on the sRVO2 of adult C. angulata, the tortoises were acclimated to 22 ± 1°C and a 14L:10D light regime prior to the RVO2 measurements. RVO2 was measured at eight experimental temperatures; 14°C, 18°C, 22°C, 26°C, 30°C, 35°C, 38°C and 40°C. The sRVO2 was not influenced by gender and increased with experimental temperatures, but this did not happen consistently over the whole range of temperatures tested. A plateau, possibly a thermal preferendum zone, was detected within the temperature range of 26 - 38°C. Determination of seasonal effect on the sRVO2 of adult C. angulata was accomplished by acclimating tortoises to standard summer and winter conditions. Seasonal effects were tested in the appropriate seasons. Winter experiments were conducted in winter and summer experiments conducted in summer. The RVO2 was measured at experimental temperature 14°C, 18°C and 22°C. In addition RVO2 of iv winter-acclimated tortoises was also measured at 10°C. The sRVO2 increased significantly with increasing temperature within the temperature range tested. No distinct pattern was observed in the seasonal acclimation of adult C. angulata. The metabolic rate-temperature curves of the summer and the winter-acclimated tortoises cross each other. Season and temperature had no significant effects on the mass-scaling exponent of the sRVO2. The exponent ranged from 0.48 to 0.73 within the temperature range of 22 - 38°C. Below and above this temperature range, the exponent ranged from 1.47 to 1.67. An inverse relationship was observed between sRVO2 and body mass over the temperature range of 22 - 38°C. At 14°C and 18°C, sRVO2 increased with body mass, while at 10°C and at 40°C the slope was 1.01.
- Full Text:
- Date Issued: 2010
Microalgal biomass and distribution in the Mngazi and Mngazana Estuaries
- Ngesi, Hlekani Ntombizakithi
- Authors: Ngesi, Hlekani Ntombizakithi
- Date: 2010
- Subjects: Microalgae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10610 , http://hdl.handle.net/10948/1591 , Microalgae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa
- Description: The present study was undertaken in the temporarily open/closed Mngazi and permanently open Mngazana estuaries, located on the subtropical east coast of South Africa. The results from this research will assist decision makers in the freshwater management of these systems. Intertidal and subtidal benthic chlorophyll a concentrations, water column chlorophyll a, nutrients and several physico-chemical parameters were measured between June 2002 and November 2003. The objective of this study was to determine if the presence of freshwater in the estuaries had an effect on the microalgae of both estuaries. Five sites were sampled in the Mngazi Estuary and 14 sites were sampled in the Mngazana Estuary. The average water column chlorophyll a was significantly higher (p<0.05) in the Mngazana Estuary (surface 7.8 ± 0.7 μg.l-1, bottom 6.4 ± 0.7 μg.l-1) compared to the Mngazi Estuary (surface 4.9 ± 1.2 μg.l-1, bottom 7.3 ± 1.5 μg.l-1). There was no evidence of an REI (river-estuary interface) zone in areas where the water column chlorophyll a concentrations were high even during open mouth conditions in the Mngazi Estuary. The REI is that area where salinity is less than 10 ppt and is characterized by high water column productivity. Even though both systems received some freshwater during the summer periods, this was not enough to stimulate phytoplankton growth and nutrient availability seems to be the major factor limiting phytoplankton in these systems. Flagellates and diatoms were the dominant phytoplankton groups in both estuaries during the entire sampling session. The relative abundance of the different phytoplankton groups did not show differences between sites. The relative abundance of flagellates was in most cases greater than 60% and diatoms made up the remainder. The average benthic chlorophyll a was higher in the Mngazana Estuary (intertidal 24 ± 6 μg.g-1 subtidal 15.2 ± 3 μg.g-1) compared to the Mngazi Estuary (intertidal 15.3 ± 4.3 μg.g-1 subtidal 5.4 ± 1.6 μg.g-1). Regions with high benthic chlorophyll a concentrations had high sediment organic content. Sediment organic content was higher in the Mngazana Estuary (1 percent - 8 percent) compared to the Mngazi Estuary (4 percent – 6.8 percent). The sites situated on the Main Channel had on average significantly higher (p<0.05) benthic chlorophyll a biomass compared to Creek 1 and Creek 2 in the Mngazana Estuary. Peaks in benthic chlorophyll a concentrations occurred in the intertidal sediments in Creek 1 (50.4 ± 13.4 μg.g-1) and Creek 2 (57.4 ± 1.4 μg.g-1) in the Mngazana Estuary, the peaks occurred in winter during a period of low freshwater inflow into the estuary. Microphytobenthic biomass measured in the Mngazi Estuary is among the lowest values reported in the literature for temporarily open/closed estuaries. Statistical 4 analysis showed no significant difference between benthic chlorophyll a during the different mouth conditions and sampling sessions in the Mngazi Estuary. Microalgal responses in the Mngazana Estuary were similar to those observed in other permanently open marine dominated estuaries. In the temporarily open/closed Mngazi Estuary microalgal characteristics were different to that of other temporarily open/closed estuaries probably because the estuary was only sampled in the open and semi-closed state.
- Full Text:
- Date Issued: 2010
- Authors: Ngesi, Hlekani Ntombizakithi
- Date: 2010
- Subjects: Microalgae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10610 , http://hdl.handle.net/10948/1591 , Microalgae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazi Estuary , Algae -- South Africa -- Mngazana Estuary , Estuarine ecology -- South Africa
- Description: The present study was undertaken in the temporarily open/closed Mngazi and permanently open Mngazana estuaries, located on the subtropical east coast of South Africa. The results from this research will assist decision makers in the freshwater management of these systems. Intertidal and subtidal benthic chlorophyll a concentrations, water column chlorophyll a, nutrients and several physico-chemical parameters were measured between June 2002 and November 2003. The objective of this study was to determine if the presence of freshwater in the estuaries had an effect on the microalgae of both estuaries. Five sites were sampled in the Mngazi Estuary and 14 sites were sampled in the Mngazana Estuary. The average water column chlorophyll a was significantly higher (p<0.05) in the Mngazana Estuary (surface 7.8 ± 0.7 μg.l-1, bottom 6.4 ± 0.7 μg.l-1) compared to the Mngazi Estuary (surface 4.9 ± 1.2 μg.l-1, bottom 7.3 ± 1.5 μg.l-1). There was no evidence of an REI (river-estuary interface) zone in areas where the water column chlorophyll a concentrations were high even during open mouth conditions in the Mngazi Estuary. The REI is that area where salinity is less than 10 ppt and is characterized by high water column productivity. Even though both systems received some freshwater during the summer periods, this was not enough to stimulate phytoplankton growth and nutrient availability seems to be the major factor limiting phytoplankton in these systems. Flagellates and diatoms were the dominant phytoplankton groups in both estuaries during the entire sampling session. The relative abundance of the different phytoplankton groups did not show differences between sites. The relative abundance of flagellates was in most cases greater than 60% and diatoms made up the remainder. The average benthic chlorophyll a was higher in the Mngazana Estuary (intertidal 24 ± 6 μg.g-1 subtidal 15.2 ± 3 μg.g-1) compared to the Mngazi Estuary (intertidal 15.3 ± 4.3 μg.g-1 subtidal 5.4 ± 1.6 μg.g-1). Regions with high benthic chlorophyll a concentrations had high sediment organic content. Sediment organic content was higher in the Mngazana Estuary (1 percent - 8 percent) compared to the Mngazi Estuary (4 percent – 6.8 percent). The sites situated on the Main Channel had on average significantly higher (p<0.05) benthic chlorophyll a biomass compared to Creek 1 and Creek 2 in the Mngazana Estuary. Peaks in benthic chlorophyll a concentrations occurred in the intertidal sediments in Creek 1 (50.4 ± 13.4 μg.g-1) and Creek 2 (57.4 ± 1.4 μg.g-1) in the Mngazana Estuary, the peaks occurred in winter during a period of low freshwater inflow into the estuary. Microphytobenthic biomass measured in the Mngazi Estuary is among the lowest values reported in the literature for temporarily open/closed estuaries. Statistical 4 analysis showed no significant difference between benthic chlorophyll a during the different mouth conditions and sampling sessions in the Mngazi Estuary. Microalgal responses in the Mngazana Estuary were similar to those observed in other permanently open marine dominated estuaries. In the temporarily open/closed Mngazi Estuary microalgal characteristics were different to that of other temporarily open/closed estuaries probably because the estuary was only sampled in the open and semi-closed state.
- Full Text:
- Date Issued: 2010
Modeling of arsenic removal from aqueous media using selected coagulants
- Authors: Majavu, Avela
- Date: 2010
- Subjects: Arsenic wastes , Water -- Purification -- Arsenic removal , Coagulation
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10426 , http://hdl.handle.net/10948/d1017100
- Description: The waste water from the industrial production of the herbicide monosodium methyl arsenate was treated using coagulation. The coagulation process as developed in this research proved to be suitable for arsenic removal in aqueous media using chromium (III), calcium (II), and combination of calcium (II) and chromium (III), and magnesium (II). The results obtained suggest that the coagulation process can be used for the treatment of the waste water from the monosodium methyl arsenate production. Response surface methodology was used to study the effects of the various parameters, namely pH, mole ratios (Cr:As, Ca:As, and Mg:As), concentration of flocculent and initial arsenic concentration. To optimize the process conditions for the maximum removal of arsenic. Central composite and factorial designs were used to study the effects of these variables and to predict the effect of each. ANOVA was used to identify those factors which had significant effects on model quality and performance. The initial arsenic concentration appeared to be the only significant factor. These models were statistically tested and verified by confirmation experiments.
- Full Text:
- Date Issued: 2010
- Authors: Majavu, Avela
- Date: 2010
- Subjects: Arsenic wastes , Water -- Purification -- Arsenic removal , Coagulation
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10426 , http://hdl.handle.net/10948/d1017100
- Description: The waste water from the industrial production of the herbicide monosodium methyl arsenate was treated using coagulation. The coagulation process as developed in this research proved to be suitable for arsenic removal in aqueous media using chromium (III), calcium (II), and combination of calcium (II) and chromium (III), and magnesium (II). The results obtained suggest that the coagulation process can be used for the treatment of the waste water from the monosodium methyl arsenate production. Response surface methodology was used to study the effects of the various parameters, namely pH, mole ratios (Cr:As, Ca:As, and Mg:As), concentration of flocculent and initial arsenic concentration. To optimize the process conditions for the maximum removal of arsenic. Central composite and factorial designs were used to study the effects of these variables and to predict the effect of each. ANOVA was used to identify those factors which had significant effects on model quality and performance. The initial arsenic concentration appeared to be the only significant factor. These models were statistically tested and verified by confirmation experiments.
- Full Text:
- Date Issued: 2010
Modelling and control of combustion in a high velocity air flame (HVAF) thermal spraying process
- Authors: Barth, Dominic
- Date: 2010
- Subjects: Metal spraying , Combustion
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9644 , http://hdl.handle.net/10948/1266 , Metal spraying , Combustion
- Description: Thermal spraying is a technology, which is used for coating of components and structures in order to achieve certain tribological characteristics, or for protection against corrosion, excessive temperature and wear. Within thermal spray, there are processes, which utilise combustion of liquid fuel to obtain high velocities flows providing, therefore, good adhesion of coating materials to substrates. These include High Velocity Oxygen Flame (HVOF) and High Velocity Air Flame (HVAF) process, of which the former one is widely used as it has been developed for at least two decades, while HVAF is less common. However, some studies indicate that HVAF has a number of advantages over HVOF, including the economic benefits. The thermal spray gun, based on the HVAF process, has been developed before, but the system was controlled manually. Therefore, there is a need to develop a fully automated controller of an HVAF thermal spray system. Process control of thermal spraying is highly complex as it involves simultaneous control of a number of processes, including; ignition process, combustion process, spraying material melting, as well as control and monitoring of auxiliary equipment. This paper presents the development of a control system for an HVAF thermal spray system, based on a Microchip PIC microcontroller. The designed control system was applied for controlling of thermal spraying of carbides powders, and provided a reliable ignition and stable combustion process, powder feeding and all other functions of control.
- Full Text:
- Date Issued: 2010
- Authors: Barth, Dominic
- Date: 2010
- Subjects: Metal spraying , Combustion
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9644 , http://hdl.handle.net/10948/1266 , Metal spraying , Combustion
- Description: Thermal spraying is a technology, which is used for coating of components and structures in order to achieve certain tribological characteristics, or for protection against corrosion, excessive temperature and wear. Within thermal spray, there are processes, which utilise combustion of liquid fuel to obtain high velocities flows providing, therefore, good adhesion of coating materials to substrates. These include High Velocity Oxygen Flame (HVOF) and High Velocity Air Flame (HVAF) process, of which the former one is widely used as it has been developed for at least two decades, while HVAF is less common. However, some studies indicate that HVAF has a number of advantages over HVOF, including the economic benefits. The thermal spray gun, based on the HVAF process, has been developed before, but the system was controlled manually. Therefore, there is a need to develop a fully automated controller of an HVAF thermal spray system. Process control of thermal spraying is highly complex as it involves simultaneous control of a number of processes, including; ignition process, combustion process, spraying material melting, as well as control and monitoring of auxiliary equipment. This paper presents the development of a control system for an HVAF thermal spray system, based on a Microchip PIC microcontroller. The designed control system was applied for controlling of thermal spraying of carbides powders, and provided a reliable ignition and stable combustion process, powder feeding and all other functions of control.
- Full Text:
- Date Issued: 2010
Molecular and cellular analysis of the interaction between soluble CD23 and CD11/CD18 integrins
- Authors: Daniels, Brodie Belinda
- Date: 2010
- Subjects: CD23 antigen , Immune response -- Regulation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10303 , http://hdl.handle.net/10948/1217 , CD23 antigen , Immune response -- Regulation
- Description: The low affinity IgE receptor, CD23, is expressed by a wide variety of cells and cleaved from its original 45 kDa size to several smaller soluble CD23 proteins. Soluble CD23 function depends on the form of the protein and its interaction with various ligands. CD23 is believed to play an important role in regulating allergic responses and in inflammation, amongst others. β2 integrins are important in a variety of cell-adhesion reactions during immune-inflammatory mechanisms and the binding of their natural ligands generates outside-in cellular signalling, leading to cell activation. Although the binding of CD23 to β2 integrins contributes to this signalling in monocytes, the interaction site for CD23 is unknown. This study focused on the interaction of three soluble CD23 proteins with the β2 integrins CD11b/CD18 and CD11c/CD18. Differentiated HL60, THP1 and U937 monocytic cells were used to demonstrate the binding of three recombinant CD23 constructs (corresponding to 16, 25 and 33 kDa human soluble CD23) to upregulated CD11b/CD18 and CD11c/CD18. This binding was partially blocked by an antibody specific for the CD11b/CD18 αI domain, demonstrating that αI domains are involved in binding to CD23. Recombinant αI domain proteins of CD11b and CD11c were demonstrated to bind CD23 using ELISA and in surface plasmon resonance spectroscopy. The dissociation constants for CD23-CD11b/CD18 and CD23-CD11c/CD18 are comparable to other integrin ligands. This study has shown that CD23 interacts directly with the αI domains of β2 integrins and that the interaction surface likely spans the lectin domain as well as either the stalk and/or C-terminal tail of CD23. This study also looked at the effect that soluble CD23 proteins had on monocyte biology. It appears that iv sCD23 proteins have little effect on the phagocytic or chemotactic ability of monocytes, while an increase in oxidative burst was shown with the 16 kDa and 25 kDa CD23 proteins. Signalling pathways for the production of reactive oxygen species were investigated and it appears that the CD23 proteins signal mainly through the phosphoinositide-3 kinase pathway, although the mitogen activated protein kinase and Src kinase pathways may also play a role. These data suggest that sCD23 proteins induce outside-in signalling of β2 integrins and are able to change the activation state of CD11b/CD11c by stimulating oxidative burst. This needs to be further investigated by determining how the three sCD23 proteins are binding the CD11 proteins and investigating further leukocyte function and inflammatory responses by the cells.
- Full Text:
- Date Issued: 2010
- Authors: Daniels, Brodie Belinda
- Date: 2010
- Subjects: CD23 antigen , Immune response -- Regulation
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:10303 , http://hdl.handle.net/10948/1217 , CD23 antigen , Immune response -- Regulation
- Description: The low affinity IgE receptor, CD23, is expressed by a wide variety of cells and cleaved from its original 45 kDa size to several smaller soluble CD23 proteins. Soluble CD23 function depends on the form of the protein and its interaction with various ligands. CD23 is believed to play an important role in regulating allergic responses and in inflammation, amongst others. β2 integrins are important in a variety of cell-adhesion reactions during immune-inflammatory mechanisms and the binding of their natural ligands generates outside-in cellular signalling, leading to cell activation. Although the binding of CD23 to β2 integrins contributes to this signalling in monocytes, the interaction site for CD23 is unknown. This study focused on the interaction of three soluble CD23 proteins with the β2 integrins CD11b/CD18 and CD11c/CD18. Differentiated HL60, THP1 and U937 monocytic cells were used to demonstrate the binding of three recombinant CD23 constructs (corresponding to 16, 25 and 33 kDa human soluble CD23) to upregulated CD11b/CD18 and CD11c/CD18. This binding was partially blocked by an antibody specific for the CD11b/CD18 αI domain, demonstrating that αI domains are involved in binding to CD23. Recombinant αI domain proteins of CD11b and CD11c were demonstrated to bind CD23 using ELISA and in surface plasmon resonance spectroscopy. The dissociation constants for CD23-CD11b/CD18 and CD23-CD11c/CD18 are comparable to other integrin ligands. This study has shown that CD23 interacts directly with the αI domains of β2 integrins and that the interaction surface likely spans the lectin domain as well as either the stalk and/or C-terminal tail of CD23. This study also looked at the effect that soluble CD23 proteins had on monocyte biology. It appears that iv sCD23 proteins have little effect on the phagocytic or chemotactic ability of monocytes, while an increase in oxidative burst was shown with the 16 kDa and 25 kDa CD23 proteins. Signalling pathways for the production of reactive oxygen species were investigated and it appears that the CD23 proteins signal mainly through the phosphoinositide-3 kinase pathway, although the mitogen activated protein kinase and Src kinase pathways may also play a role. These data suggest that sCD23 proteins induce outside-in signalling of β2 integrins and are able to change the activation state of CD11b/CD11c by stimulating oxidative burst. This needs to be further investigated by determining how the three sCD23 proteins are binding the CD11 proteins and investigating further leukocyte function and inflammatory responses by the cells.
- Full Text:
- Date Issued: 2010
Motivation and complexity : an exploration of a complexity approach in employee motivation with specific focus on a Lacanian model of desire
- Authors: Botha, Anton Ivan
- Date: 2010
- Subjects: Employee motivation , Employee morale , Incentive awards
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:9400 , http://hdl.handle.net/10948/1232 , Employee motivation , Employee morale , Incentive awards
- Description: Since employee motivation contributes to overall organisational success, reliable motivation theory should inform management and reward practices. Yet, motivation theory is currently in a state of paralysis, with no constructive theorising taking place. Analysis of its methodological presuppositions reveals that it relies on out-dated binary thinking, prioritising, e.g. either a ‘machine-like’ (body driven) or ‘god-like’ (rationally driven) understanding of humanity. In this study it is argued that the revival of motivation theory requires a paradigmatic shift towards a complexity methodology because human motivation was found to be a complex system and must be theorised accordingly. It was found that McAdams’ theory of personality which brought together personality traits, conditioning, and motives could form the basis of a complex theory of motivation. On this basis, a complex model was developed which incorporated elements of existing motivational theories. This model proposed that drives, which motivate behaviour, are a combination of instincts, needs, and desires, mediated by personality traits, rational processing, and conditioning. All of these interconnected elements, as well as biological and environmental conditions, have an impact on, and are influenced by one another. For the purposes of understanding employee motivation the element of desire was isolated as a potential means to value segment employees. A Lacanian theory was utilised to elaborate on the element of desire. This theory postulated that individuals tend to display a dominance is one of nine kinds and modes of desire. An instrument was developed to test the applicability of the Lacanian model. It was developed in five phases which included three pilot studies and two samplings. A total of 591 respondents participated in the empirical research study with 428 in the first sample and 70 in the second; the remaining 93 made up the pilot studies. Unlike the initial version of the instrument used in the first sample (n=428) the data obtained by the last version (n=70) revealed that the instrument held some form of reliability and validity. Once analysed through descriptive and inferential statistics the data supported the view that individuals tended to display dominance in a kind and mode of desire as per the Lacanian model, and sufficient variance existed to preliminarily conclude that this model could be used as a means to value segment employees. Recommendations were as follows: (1) that complexity methodology should inform future motivation theorising, (2) that the proposed complexity models be further empirically tested, (3) that an adequately complex, flexible rewards system be considered, (4) that both managers and employees make use of the developed instrument to aid them in the selection of rewards that will lead to increased satisfaction.
- Full Text:
- Date Issued: 2010
- Authors: Botha, Anton Ivan
- Date: 2010
- Subjects: Employee motivation , Employee morale , Incentive awards
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:9400 , http://hdl.handle.net/10948/1232 , Employee motivation , Employee morale , Incentive awards
- Description: Since employee motivation contributes to overall organisational success, reliable motivation theory should inform management and reward practices. Yet, motivation theory is currently in a state of paralysis, with no constructive theorising taking place. Analysis of its methodological presuppositions reveals that it relies on out-dated binary thinking, prioritising, e.g. either a ‘machine-like’ (body driven) or ‘god-like’ (rationally driven) understanding of humanity. In this study it is argued that the revival of motivation theory requires a paradigmatic shift towards a complexity methodology because human motivation was found to be a complex system and must be theorised accordingly. It was found that McAdams’ theory of personality which brought together personality traits, conditioning, and motives could form the basis of a complex theory of motivation. On this basis, a complex model was developed which incorporated elements of existing motivational theories. This model proposed that drives, which motivate behaviour, are a combination of instincts, needs, and desires, mediated by personality traits, rational processing, and conditioning. All of these interconnected elements, as well as biological and environmental conditions, have an impact on, and are influenced by one another. For the purposes of understanding employee motivation the element of desire was isolated as a potential means to value segment employees. A Lacanian theory was utilised to elaborate on the element of desire. This theory postulated that individuals tend to display a dominance is one of nine kinds and modes of desire. An instrument was developed to test the applicability of the Lacanian model. It was developed in five phases which included three pilot studies and two samplings. A total of 591 respondents participated in the empirical research study with 428 in the first sample and 70 in the second; the remaining 93 made up the pilot studies. Unlike the initial version of the instrument used in the first sample (n=428) the data obtained by the last version (n=70) revealed that the instrument held some form of reliability and validity. Once analysed through descriptive and inferential statistics the data supported the view that individuals tended to display dominance in a kind and mode of desire as per the Lacanian model, and sufficient variance existed to preliminarily conclude that this model could be used as a means to value segment employees. Recommendations were as follows: (1) that complexity methodology should inform future motivation theorising, (2) that the proposed complexity models be further empirically tested, (3) that an adequately complex, flexible rewards system be considered, (4) that both managers and employees make use of the developed instrument to aid them in the selection of rewards that will lead to increased satisfaction.
- Full Text:
- Date Issued: 2010