The influence of indigenous languages on Ugandan English as used in the media
- Authors: Tukwasibwe, Constance
- Date: 2014
- Subjects: Mass media and language -- Uganda , Languages in contact -- Uganda , English language -- Uganda , Language transfer (Language learning) -- Uganda , Communication and culture -- Uganda , Bilingualism -- Uganda , Linguistic demography -- Uganda , Uganda -- Languages
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3646 , http://hdl.handle.net/10962/d1015637
- Description: When two or more languages come in contact, they influence each other in various ways, for example through word borrowing, transfer of sounds, morphology and syntax taken from one language system and imported to another. In this study, the primary concern is on the indigenous communities of Uganda learning the English language, plus the influence that this interaction brings into the linguistic space. Bringing the Ugandan multilingual situation into perspective, the study looks at how the English language has interacted with the local languages and the local speech habits, customs and traditions of the indigenous people, to the extent that it has been indigenized. Some word usage results in miscommunication due to the socio-cultural uniqueness of Ugandan cultural expressions. As an example, because of the practice of polygamy in most Ugandan cultures, words like co-wife are coined to mean 'a woman who shares a husband, or a husband's other wife', a word that is absent in both the language and culture of native English speakers. Furthermore some words are formed by calquing some indigenous language expressions, e.g. 'to eat money' or 'to eat cash', an expression that is calqued from the Luganda phrase, kulya sente. Such word coinages are meant to fill the 'shortfall' where the English language fails to provide adequate equivalents. Understanding the context of this kind of English usage and the influence from the indigenous languages is helpful in handling inter-cultural discourses, as the same expression may convey different senses to different people in different contexts. So then, this study deals with some peculiarities of Ugandan English, namely; the features of Ugandan English grammar which are influenced by the indigenous languages. Evidence from the Corpus of Ugandan English is explored to establish that indigenous languages in Uganda have a significant influence on the English language variety spoken in the country, and that a large part of English bilingual speakers cannot speak English without transferring the features from their mother tongue or indeed, switching and mixing codes. A British corpus was used for the purposes of comparison with Ugandan English. The research was conducted in Uganda, drawing data from English newspapers, radio and television talk -shows that were recorded to provide a structural analysis of the contact situations. The result of the study points to the fact that, indeed, the phonological, morpho-syntactic and semantic characteristics of Ugandan English have a considerable amount of influence from indigenous local languages. This study is hinged on the assumption that when indigenous languages and the target language come together in a linguistic contact situation, the resulting variety would exhibit distinct phonological, lexical, grammatical and semantic/pragmatic features ( cf. Sankoff, 2001; Thomason, 1995; Thomason & Kaufman, 1988; Winford, 2005). However, some of these innovations have attracted criticism from 'prescriptivists' such as Quirk (1985, 1988, 1990); Gaudio (2011); and Abbot (1991) who perceive them as 'nonstandard', 'incorrect English language usage' and a 'direct translation from the language user's mother tongue into English'. Yet, indigenous languages continue to play important roles in shaping the kind of English language usage in Uganda.
- Full Text:
- Date Issued: 2014
- Authors: Tukwasibwe, Constance
- Date: 2014
- Subjects: Mass media and language -- Uganda , Languages in contact -- Uganda , English language -- Uganda , Language transfer (Language learning) -- Uganda , Communication and culture -- Uganda , Bilingualism -- Uganda , Linguistic demography -- Uganda , Uganda -- Languages
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3646 , http://hdl.handle.net/10962/d1015637
- Description: When two or more languages come in contact, they influence each other in various ways, for example through word borrowing, transfer of sounds, morphology and syntax taken from one language system and imported to another. In this study, the primary concern is on the indigenous communities of Uganda learning the English language, plus the influence that this interaction brings into the linguistic space. Bringing the Ugandan multilingual situation into perspective, the study looks at how the English language has interacted with the local languages and the local speech habits, customs and traditions of the indigenous people, to the extent that it has been indigenized. Some word usage results in miscommunication due to the socio-cultural uniqueness of Ugandan cultural expressions. As an example, because of the practice of polygamy in most Ugandan cultures, words like co-wife are coined to mean 'a woman who shares a husband, or a husband's other wife', a word that is absent in both the language and culture of native English speakers. Furthermore some words are formed by calquing some indigenous language expressions, e.g. 'to eat money' or 'to eat cash', an expression that is calqued from the Luganda phrase, kulya sente. Such word coinages are meant to fill the 'shortfall' where the English language fails to provide adequate equivalents. Understanding the context of this kind of English usage and the influence from the indigenous languages is helpful in handling inter-cultural discourses, as the same expression may convey different senses to different people in different contexts. So then, this study deals with some peculiarities of Ugandan English, namely; the features of Ugandan English grammar which are influenced by the indigenous languages. Evidence from the Corpus of Ugandan English is explored to establish that indigenous languages in Uganda have a significant influence on the English language variety spoken in the country, and that a large part of English bilingual speakers cannot speak English without transferring the features from their mother tongue or indeed, switching and mixing codes. A British corpus was used for the purposes of comparison with Ugandan English. The research was conducted in Uganda, drawing data from English newspapers, radio and television talk -shows that were recorded to provide a structural analysis of the contact situations. The result of the study points to the fact that, indeed, the phonological, morpho-syntactic and semantic characteristics of Ugandan English have a considerable amount of influence from indigenous local languages. This study is hinged on the assumption that when indigenous languages and the target language come together in a linguistic contact situation, the resulting variety would exhibit distinct phonological, lexical, grammatical and semantic/pragmatic features ( cf. Sankoff, 2001; Thomason, 1995; Thomason & Kaufman, 1988; Winford, 2005). However, some of these innovations have attracted criticism from 'prescriptivists' such as Quirk (1985, 1988, 1990); Gaudio (2011); and Abbot (1991) who perceive them as 'nonstandard', 'incorrect English language usage' and a 'direct translation from the language user's mother tongue into English'. Yet, indigenous languages continue to play important roles in shaping the kind of English language usage in Uganda.
- Full Text:
- Date Issued: 2014
Curriculum outcomes, teaching practices and learner competencies in isiXhosa in three Grahamstown schools
- Authors: Fobe, Mila Pamella
- Date: 2014
- Subjects: Xhosa language -- Study and teaching (Primary) -- South Africa -- Grahamstown Xhosa language -- Study and teaching (Secondary) -- South Africa -- Grahamstown Language and education -- South Africa -- Grahamstown Curriculum planning Second language acquisition Public schools -- South Africa -- Grahamstown Language policy -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3630 , http://hdl.handle.net/10962/d1012072
- Description: This study looks at the curriculum outcomes, teaching practices and learner competencies in isiXhosa at three Eastern Cape schools and across three different grades, 7-9. It explores the link between language learning and teaching as well as the teaching strategies used within the classroom. In particular, the study seeks to analyse how isiXhosa is taught at three different levels of instruction, namely at Home Language (HL), First Additional Language (FAL) and Second Additional Language (SAL) levels. Qualitative methods were used, and the study took the form of interpretive case studies within the respective schools. The purpose of using multiple case studies was to investigate the reality within the three sites selected. The three schools had three extreme settings, in the sense that one of the schools is a rich isiXhosa environment and the other two schools are English environments. The tools used for data gathering were interviews, classroom observations, and an analysis of documents from the Department of Basic Education. Data was then presented and analysed in Chapter 4 and 5 against the backdrop of an extensive literature review in Chapter 2 as well as a detailed methodological approach as outlined in Chapter 3. One of the findings of this research indicates that in two of the schools the teaching culture is largely from a western perspective, whereas in one of the schools the learners are primarily isiXhosa speaking and teachers use a different linguistic approach to imparting knowledge. In the private and ex-Model C school it was found that a lack of exposure to isiXhosa is the primary cause of language problems for L2 learners. Secondly the L1 is not appropriately maintained or promoted in the school environment because it is presumed that learners are sufficiently exposed to their L1 at home. The research found therefore that in this particular schooling environment there is an inconsistency between the curricula that is taught in relation to the linguistic abilities of the learners, many of whom are mother tongue speakers of isiXhosa. Furthermore and more generally, it was found that teachers are still not well informed concerning South Africa’s Language-in-Education-Policy and there is a need for more inservice training that will focus on the nature of additional language acquisition in order to address the challenges of teaching these languages. The thesis concludes that extensive work needs to be done in order to reposition the teaching of isiXhosa at all three levels, but particularly at FAL level. This research shows that there is a disjuncture between the proposed curriculum/learning outcomes and the standards or levels achieved by the learners, more especially at FAL and SAL where oral proficiency in isiXhosa remains a challenge. Specific recommendations are contained in the final chapter of the thesis which also makes reference to the draft policy of the Ministry of Basic Education regarding the incremental introduction of the teaching of African languages from 2014 onwards. This thesis also makes takes as a point of departure the importance of multilingualism in a multicultural society such as South Africa where language is suggested as a strong factor in the fostering of social cohesion. It is for this reason that the thesis argues that the expert teaching of African languages, in this case isiXhosa, at both mother tongue and second language levels is of fundamental importance to the future of South African society.
- Full Text:
- Date Issued: 2014
- Authors: Fobe, Mila Pamella
- Date: 2014
- Subjects: Xhosa language -- Study and teaching (Primary) -- South Africa -- Grahamstown Xhosa language -- Study and teaching (Secondary) -- South Africa -- Grahamstown Language and education -- South Africa -- Grahamstown Curriculum planning Second language acquisition Public schools -- South Africa -- Grahamstown Language policy -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3630 , http://hdl.handle.net/10962/d1012072
- Description: This study looks at the curriculum outcomes, teaching practices and learner competencies in isiXhosa at three Eastern Cape schools and across three different grades, 7-9. It explores the link between language learning and teaching as well as the teaching strategies used within the classroom. In particular, the study seeks to analyse how isiXhosa is taught at three different levels of instruction, namely at Home Language (HL), First Additional Language (FAL) and Second Additional Language (SAL) levels. Qualitative methods were used, and the study took the form of interpretive case studies within the respective schools. The purpose of using multiple case studies was to investigate the reality within the three sites selected. The three schools had three extreme settings, in the sense that one of the schools is a rich isiXhosa environment and the other two schools are English environments. The tools used for data gathering were interviews, classroom observations, and an analysis of documents from the Department of Basic Education. Data was then presented and analysed in Chapter 4 and 5 against the backdrop of an extensive literature review in Chapter 2 as well as a detailed methodological approach as outlined in Chapter 3. One of the findings of this research indicates that in two of the schools the teaching culture is largely from a western perspective, whereas in one of the schools the learners are primarily isiXhosa speaking and teachers use a different linguistic approach to imparting knowledge. In the private and ex-Model C school it was found that a lack of exposure to isiXhosa is the primary cause of language problems for L2 learners. Secondly the L1 is not appropriately maintained or promoted in the school environment because it is presumed that learners are sufficiently exposed to their L1 at home. The research found therefore that in this particular schooling environment there is an inconsistency between the curricula that is taught in relation to the linguistic abilities of the learners, many of whom are mother tongue speakers of isiXhosa. Furthermore and more generally, it was found that teachers are still not well informed concerning South Africa’s Language-in-Education-Policy and there is a need for more inservice training that will focus on the nature of additional language acquisition in order to address the challenges of teaching these languages. The thesis concludes that extensive work needs to be done in order to reposition the teaching of isiXhosa at all three levels, but particularly at FAL level. This research shows that there is a disjuncture between the proposed curriculum/learning outcomes and the standards or levels achieved by the learners, more especially at FAL and SAL where oral proficiency in isiXhosa remains a challenge. Specific recommendations are contained in the final chapter of the thesis which also makes reference to the draft policy of the Ministry of Basic Education regarding the incremental introduction of the teaching of African languages from 2014 onwards. This thesis also makes takes as a point of departure the importance of multilingualism in a multicultural society such as South Africa where language is suggested as a strong factor in the fostering of social cohesion. It is for this reason that the thesis argues that the expert teaching of African languages, in this case isiXhosa, at both mother tongue and second language levels is of fundamental importance to the future of South African society.
- Full Text:
- Date Issued: 2014
Purification and characterization of TbHsp70.c, a novel Hsp70 from Trypanosoma brucei
- Authors: Burger, Adélle
- Date: 2014
- Subjects: African trypanosomiasis -- Research Heat shock proteins -- Research Trypanosoma brucei -- Research Mycobacterial diseases -- Research -- Africa Parasitic diseases -- Africa -- Prevention Parasites -- Physiology Developing countries -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4105 , http://hdl.handle.net/10962/d1011618
- Description: One of Africa’s neglected tropical diseases, African Trypanosomiasis, is not only fatal but also has a crippling impact on economic development. Heat shock proteins play a wide range of roles in the cell and they are required to assist the parasite as it moves from a cold blooded insect vector to a warm blooded mammalian host. The expression of heat shock proteins increases during these heat shock conditions, and this is considered to play a role in differentiation of these vector-borne parasites. Heat shock protein 70 (Hsp70) is an important molecular chaperone that is involved in protein homeostasis, Hsp40 acts as a co-chaperone and stimulates its intrinsically weak ATPase activity. In silico analysis of the T. brucei genome has revealed the existence of 12 Hsp70 proteins and 65 Hsp40 proteins to date. A novel Hsp70, TbHsp70.c, was recently identified in T. brucei. Different from the prototypical Hsp70, TbHsp70.c contains an acidic substrate binding domain and lacks the C-terminal EEVD motif. By implication the substrate range and mechanism by which the substrates are recognized may be novel. The ability of a Type I Hsp40, Tbj2, to function as a co-chaperone of TbHsp70.c was investigated. The main objective of this study was to biochemically characterize TbHsp70.c and its partnership with Tbj2 to further enhance our knowledge of parasite biology. TbHsp70.c and Tbj2 were heterologously expressed and purified and both proteins displayed chaperone activities in their ability to suppress aggregation of thermolabile MDH. TbHsp70.c also suppressed aggregation of rhodanese. ATPase assays revealed that the ATPase activity of TbHsp70.c was stimulated by Tbj2. The targeted inhibition of the function of heat shock proteins is emerging as a tool to combat disease. The small molecule modulators quercetin and methylene blue are known to inhibit the ATPase activity of Hsp70. However, methylene blue did not significantly inhibit the ATPase activity of TbHsp70.c; while quercetin, did inhibit the ATPase activity. In vivo heat stress experiments indicated an up-regulation of the expression levels of TbHsp70.c. RNA interference studies showed partial knockdown of TbHsp70.c with no detrimental effect on the parasite. Fluorescence microscopy studies of TbHsp70.c showed a probable cytoplasmic subcellular localization. In this study both TbHsp70.c and Tbj2 demonstrated chaperone activity and Tbj2 possibly functions as a co-chaperone of TbHsp70.c.
- Full Text:
- Date Issued: 2014
- Authors: Burger, Adélle
- Date: 2014
- Subjects: African trypanosomiasis -- Research Heat shock proteins -- Research Trypanosoma brucei -- Research Mycobacterial diseases -- Research -- Africa Parasitic diseases -- Africa -- Prevention Parasites -- Physiology Developing countries -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4105 , http://hdl.handle.net/10962/d1011618
- Description: One of Africa’s neglected tropical diseases, African Trypanosomiasis, is not only fatal but also has a crippling impact on economic development. Heat shock proteins play a wide range of roles in the cell and they are required to assist the parasite as it moves from a cold blooded insect vector to a warm blooded mammalian host. The expression of heat shock proteins increases during these heat shock conditions, and this is considered to play a role in differentiation of these vector-borne parasites. Heat shock protein 70 (Hsp70) is an important molecular chaperone that is involved in protein homeostasis, Hsp40 acts as a co-chaperone and stimulates its intrinsically weak ATPase activity. In silico analysis of the T. brucei genome has revealed the existence of 12 Hsp70 proteins and 65 Hsp40 proteins to date. A novel Hsp70, TbHsp70.c, was recently identified in T. brucei. Different from the prototypical Hsp70, TbHsp70.c contains an acidic substrate binding domain and lacks the C-terminal EEVD motif. By implication the substrate range and mechanism by which the substrates are recognized may be novel. The ability of a Type I Hsp40, Tbj2, to function as a co-chaperone of TbHsp70.c was investigated. The main objective of this study was to biochemically characterize TbHsp70.c and its partnership with Tbj2 to further enhance our knowledge of parasite biology. TbHsp70.c and Tbj2 were heterologously expressed and purified and both proteins displayed chaperone activities in their ability to suppress aggregation of thermolabile MDH. TbHsp70.c also suppressed aggregation of rhodanese. ATPase assays revealed that the ATPase activity of TbHsp70.c was stimulated by Tbj2. The targeted inhibition of the function of heat shock proteins is emerging as a tool to combat disease. The small molecule modulators quercetin and methylene blue are known to inhibit the ATPase activity of Hsp70. However, methylene blue did not significantly inhibit the ATPase activity of TbHsp70.c; while quercetin, did inhibit the ATPase activity. In vivo heat stress experiments indicated an up-regulation of the expression levels of TbHsp70.c. RNA interference studies showed partial knockdown of TbHsp70.c with no detrimental effect on the parasite. Fluorescence microscopy studies of TbHsp70.c showed a probable cytoplasmic subcellular localization. In this study both TbHsp70.c and Tbj2 demonstrated chaperone activity and Tbj2 possibly functions as a co-chaperone of TbHsp70.c.
- Full Text:
- Date Issued: 2014
Can expansive (social) learning processes strengthen organisational learning for improved wetland management in a plantation forestry company, and if so how? : a case study of Mondi
- Authors: Lindley, David Stewart
- Date: 2014
- Subjects: Mondi Group , Wetland management -- South Africa , Wetland conservation -- Study and teaching (Continuing education) , Employees -- Training of -- South Africa , Action theory , Critical realism , Social learning , Environmental education -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2003 , http://hdl.handle.net/10962/d1015661
- Description: Mondi is an international packaging and paper company that manages over 300 000 ha of land in South Africa. After over a decade of working with Mondi to improve its wetland management, wetland sustainability practices were still not integrated into the broader forestry operations, despite some significant cases of successful wetland rehabilitation. An interventionist research project was therefore conducted to explore the factors inhibiting improved wetland management, and determine if and how expansive social learning processes could strengthen organisational learning and development to overcome these factors. In doing so, the research has investigated how informal adult learning supports organisational change to strengthen wetland and environmental sustainability practices, within a corporate plantation forestry context. How individual and/or group-based learning interactions translate to the collective, at the level of organisational change was a key issue probed in this study. The following three research questions were used to guide the research: 1. What tensions and contradictions exist in wetland management in a plantation forestry company? 2. Can expansive learning begin to address the tensions and contradictions that exist in wetland management in a plantation forestry company, for improved sustainability practices? 3. Can expansive social learning strengthen organisational learning and development, enabling Mondi to improve its wetland sustainability practices, and if so how does it do this? Cultural historical activity theory (CHAT) and the theory of expansive learning provided an epistemological framework for the research. The philosophy of critical realism gave ontological depth to the research, and contributed to a deeper understanding of CHAT and expansive learning. Critical realism was therefore used as a philosophy to underlabour the theoretical framework of the research. However CHAT and expansive learning could not provide the depth of detail required to explain how the expansive learning, organisational social change, and boundary crossings that are necessary for assembling the collective were taking place. Realist social theory (developed out of critical realism by Margaret Archer as an ontologically located theory of how and why social change occurs, or does not) supported the research to do this. The morphogenetic framework was used as a methodology for applying realist social theory. The expansive learning cycle was used as a methodology for applying CHAT and the theory of expansive learning; guiding the development of new knowledge creation required by Mondi staff to identify contradictions and associated tensions inhibiting wetland management, understand their root causes, and develop solutions. Through the expansive learning process, the tensions and contradictions become generative as a tool supporting expansive social learning, rather than as a means to an end where universal consensus was reached on how to circumvent the contradictions. The research was conducted in five phases: • Phase 1: Contextual profiling to identify and describe three activity systems in Mondi responsible for wetland management: 1) siviculture foresters; 2) environmental specialists; 3) community engagement facilitators. The data was generated and analysed through through document analysis, 17 interviews, 2nd generation CHAT analysis, and Critical Realist generative mechanism analysis; • Phase 2: Analysis and identification of tensions and contradictions through a first interventionist workshop. Modelling new solutions to deal with contractions, and examining and testing new models in and after the second interventionist workshop; • Phase 3: Implementing new models as wetland management projects and involved project implementation. This included boundary crossing practices of staff in the three activity systems, reflection and re-view in a further five progress review/interventionist workshops, and a management meeting and seminar; • Phase 4: Reflecting on the expansive learning process, results, and consolidation of changed practices, through nine reflective interviews and field observations; • Phase 5: Morphogenic/stasis analysis of the organisational change and development catalysed via the expansive social learning process (or not). The research found that expansive social learning processes supported organisational learning and development for improved wetland management by: 1) strengthening the scope, depth, and sophistication of participant understanding; 2) expanding the ways staff interact and collaboratively work together; 3) democratising decision making; 4) improving social relations between staff, reducing power differentials, and creating stronger relationships; 5) enhancing participant reflexivity through deeper understanding of social structures and cultural systems, and changing them to support improved wetland and environmental practice of staff, and developing the organisational structures and processes to strengthen organisational learning and development; and 6) using the contradictions identified as generative mechanisms to stimulate and catalyse organisational learning and development for changed wetland/environmental management.
- Full Text:
- Date Issued: 2014
- Authors: Lindley, David Stewart
- Date: 2014
- Subjects: Mondi Group , Wetland management -- South Africa , Wetland conservation -- Study and teaching (Continuing education) , Employees -- Training of -- South Africa , Action theory , Critical realism , Social learning , Environmental education -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2003 , http://hdl.handle.net/10962/d1015661
- Description: Mondi is an international packaging and paper company that manages over 300 000 ha of land in South Africa. After over a decade of working with Mondi to improve its wetland management, wetland sustainability practices were still not integrated into the broader forestry operations, despite some significant cases of successful wetland rehabilitation. An interventionist research project was therefore conducted to explore the factors inhibiting improved wetland management, and determine if and how expansive social learning processes could strengthen organisational learning and development to overcome these factors. In doing so, the research has investigated how informal adult learning supports organisational change to strengthen wetland and environmental sustainability practices, within a corporate plantation forestry context. How individual and/or group-based learning interactions translate to the collective, at the level of organisational change was a key issue probed in this study. The following three research questions were used to guide the research: 1. What tensions and contradictions exist in wetland management in a plantation forestry company? 2. Can expansive learning begin to address the tensions and contradictions that exist in wetland management in a plantation forestry company, for improved sustainability practices? 3. Can expansive social learning strengthen organisational learning and development, enabling Mondi to improve its wetland sustainability practices, and if so how does it do this? Cultural historical activity theory (CHAT) and the theory of expansive learning provided an epistemological framework for the research. The philosophy of critical realism gave ontological depth to the research, and contributed to a deeper understanding of CHAT and expansive learning. Critical realism was therefore used as a philosophy to underlabour the theoretical framework of the research. However CHAT and expansive learning could not provide the depth of detail required to explain how the expansive learning, organisational social change, and boundary crossings that are necessary for assembling the collective were taking place. Realist social theory (developed out of critical realism by Margaret Archer as an ontologically located theory of how and why social change occurs, or does not) supported the research to do this. The morphogenetic framework was used as a methodology for applying realist social theory. The expansive learning cycle was used as a methodology for applying CHAT and the theory of expansive learning; guiding the development of new knowledge creation required by Mondi staff to identify contradictions and associated tensions inhibiting wetland management, understand their root causes, and develop solutions. Through the expansive learning process, the tensions and contradictions become generative as a tool supporting expansive social learning, rather than as a means to an end where universal consensus was reached on how to circumvent the contradictions. The research was conducted in five phases: • Phase 1: Contextual profiling to identify and describe three activity systems in Mondi responsible for wetland management: 1) siviculture foresters; 2) environmental specialists; 3) community engagement facilitators. The data was generated and analysed through through document analysis, 17 interviews, 2nd generation CHAT analysis, and Critical Realist generative mechanism analysis; • Phase 2: Analysis and identification of tensions and contradictions through a first interventionist workshop. Modelling new solutions to deal with contractions, and examining and testing new models in and after the second interventionist workshop; • Phase 3: Implementing new models as wetland management projects and involved project implementation. This included boundary crossing practices of staff in the three activity systems, reflection and re-view in a further five progress review/interventionist workshops, and a management meeting and seminar; • Phase 4: Reflecting on the expansive learning process, results, and consolidation of changed practices, through nine reflective interviews and field observations; • Phase 5: Morphogenic/stasis analysis of the organisational change and development catalysed via the expansive social learning process (or not). The research found that expansive social learning processes supported organisational learning and development for improved wetland management by: 1) strengthening the scope, depth, and sophistication of participant understanding; 2) expanding the ways staff interact and collaboratively work together; 3) democratising decision making; 4) improving social relations between staff, reducing power differentials, and creating stronger relationships; 5) enhancing participant reflexivity through deeper understanding of social structures and cultural systems, and changing them to support improved wetland and environmental practice of staff, and developing the organisational structures and processes to strengthen organisational learning and development; and 6) using the contradictions identified as generative mechanisms to stimulate and catalyse organisational learning and development for changed wetland/environmental management.
- Full Text:
- Date Issued: 2014
Establishing a formulation design space for a generic clobetasol 17- propionate cream using the principles of quality by design
- Fauzee, Ayeshah Fateemah Beebee
- Authors: Fauzee, Ayeshah Fateemah Beebee
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:20983 , http://hdl.handle.net/10962/5868
- Description: The pharmaceutical industry is global, is highly regulated and is able to achieve reasonable product quality but at high cost with maximum effort. Numerous challenges face the pharmaceutical industry and include a shrinking research pipeline, less innovation, outsourcing, investments, increasing research and development costs, long approval times, growth of the generic industry, failure to understand or analyze manufacturing failure and wastage as high at fifty percent for some pharmaceutical products. An efficient and flexible pharmaceutical sector should be able to consistently produce high quality pharmaceutical products at a reduced cost with minimal waste. As a result, Food and Drug Administration (FDA) and other agencies such as the International Conference on Harmonization (ICH) have embraced a “Quality by Design” (QbD) paradigm and this has become the “desired state” so as to shift manufacturing from being empirical to a science, engineering, and risk based approach. QbD is a systematic approach for the development of high quality pharmaceutical dosage forms that begins with predefined objectives based on the premise that quality must be built into and not tested into a product. QbD together with the establishment of a design space for dosage forms is a fairly new concept and there is limited published data on QbD concepts that report the entire process of identifying Critical Quality Attributes (CQA), design of a formulation and manufacturing process to meet product CQA, understanding the impact of material attributes and process parameters on product CQA, identification and controlling sources of variability in materials and processes that affect the CQA of a product and finally establishing, evaluating and testing a design space using both in vitro and in vivo approaches to assure that a product of consistent quality can always be produced. The objective of these studies was to implement a QbD approach to establish a design space for the development and manufacture of a safe, effective, stable generic formulation containing 0.05% w/w clobetasol 17-propionate (CP) that had similar in vitro and in vivo characteristics to an innovator product, Dermovate® (Sekpharma® Pty Ltd, Sandton, Gauteng, RSA). Such a product would pose a minimal risk of failure when treating severe skin disorders such as seborrhoeic dermatitis, extreme photodermatitis and/or severe psoriasis in HIV/AIDS patients in Southern Africa.
- Full Text:
- Date Issued: 2014
- Authors: Fauzee, Ayeshah Fateemah Beebee
- Date: 2014
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:20983 , http://hdl.handle.net/10962/5868
- Description: The pharmaceutical industry is global, is highly regulated and is able to achieve reasonable product quality but at high cost with maximum effort. Numerous challenges face the pharmaceutical industry and include a shrinking research pipeline, less innovation, outsourcing, investments, increasing research and development costs, long approval times, growth of the generic industry, failure to understand or analyze manufacturing failure and wastage as high at fifty percent for some pharmaceutical products. An efficient and flexible pharmaceutical sector should be able to consistently produce high quality pharmaceutical products at a reduced cost with minimal waste. As a result, Food and Drug Administration (FDA) and other agencies such as the International Conference on Harmonization (ICH) have embraced a “Quality by Design” (QbD) paradigm and this has become the “desired state” so as to shift manufacturing from being empirical to a science, engineering, and risk based approach. QbD is a systematic approach for the development of high quality pharmaceutical dosage forms that begins with predefined objectives based on the premise that quality must be built into and not tested into a product. QbD together with the establishment of a design space for dosage forms is a fairly new concept and there is limited published data on QbD concepts that report the entire process of identifying Critical Quality Attributes (CQA), design of a formulation and manufacturing process to meet product CQA, understanding the impact of material attributes and process parameters on product CQA, identification and controlling sources of variability in materials and processes that affect the CQA of a product and finally establishing, evaluating and testing a design space using both in vitro and in vivo approaches to assure that a product of consistent quality can always be produced. The objective of these studies was to implement a QbD approach to establish a design space for the development and manufacture of a safe, effective, stable generic formulation containing 0.05% w/w clobetasol 17-propionate (CP) that had similar in vitro and in vivo characteristics to an innovator product, Dermovate® (Sekpharma® Pty Ltd, Sandton, Gauteng, RSA). Such a product would pose a minimal risk of failure when treating severe skin disorders such as seborrhoeic dermatitis, extreme photodermatitis and/or severe psoriasis in HIV/AIDS patients in Southern Africa.
- Full Text:
- Date Issued: 2014
Mobilising processes of abstraction, experiential learning and representation of traditional ecological knowledge in participatory monitoring of mangroves and fisheries : an approach towards enhancing social learning processes on the eastern coast of Tanzania
- Authors: Sabai, Daniel
- Date: 2014
- Subjects: Traditional ecological knowledge , Environmental education -- Tanzania , Environmental education -- Study and teaching -- Tanzania , Coastal zone management -- Tanzania , Social learning -- Tanzania , Experiential learning -- Tanzania , Mangrove conservation -- Tanzania , Fishery management -- Tanzania
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1979 , http://hdl.handle.net/10962/d1013060
- Description: This study addresses a core problem that was uncovered in records from coastal management monitoring initiatives on the eastern coast of Tanzania associated with the application and use of coastal monitoring indicators developed by external development partners for the coastal zone. These records suggest that local communities, who are key actors in participatory monitoring of coastal and marine resources, face many challenges associated with adapting and applying the said frameworks of indicators and monitoring plans. These indicators tend to be scientifically abstracted and methodologically reified; given prevailing contextual and socio‐cultural realities amongst them. The research project addresses the following key research question: How can processes of abstraction, conceptualisation, and representation of TEK contribute to the development of coastal management indicators that are less reified, more contextually and culturally congruent, and which may potentially be used by resource users in the wider social learning process of detecting trends, threats, changes and conditions of mangrove and fisheries resources? In response to the contextual problem and the research question, the study employs processes of abstraction and experiential learning techniques to unlock knowledge that local communities have, as an input for underlabouring existing scientific indicators on the Eastern coast of Tanzania. The research is constituted as critical realist case study research, involving two communities on the eastern coast of Tanzania, namely the Moa and the Boma communities (in Mkinga coastal district). Overall, the study involved 37 participants in a series of interviews, focus group discussions, and experiential learning processes using visualised data, and an experiential learning intervention workshop, and follow‐ups over a period of 3 years. The study worked with mangroves and fisheries to provide focus to the case study research and to allow for in‐depth engagement with the assumptions and processes associated with indicators development and use. Through the above mentioned data generation processes, critical realist analysis, and experiential learning processes involving abstraction and representation of traditional ecological knowledge held by mangrove restorers and fishers in the study areas, the study uncovers possible challenges of adapting and applying scientific indicators in participatory monitoring of a mangrove ecosystem. Using ampliative modes of inference for data analysis (induction, abduction and retroduction) and a critical realist scientific explanatory framework known as DRRREI(C) (Resolution, Re‐description, Retrodiction, Elimination, Identification, & Correction) the study suggests a new approach that may lead to the development of a framework of indicators that are less reified, more congruent to users (coastal communities), and likely to attract a wider context‐based social learning which favours epistemological access between scientific institutions (universities inclusive), and local communities. It attempts to establish an interface between knowledge that scientific institutions produce and the potential knowledge that exists in local contexts (traditional ecological knowledge), and seeks to widen and improve knowledge sharing and experiential learning practices that may potentially benefit coastal and marine resources in the study area. As mentioned above, the knowledge and abstraction processes related to the indicators development focussed on the mangrove ecosystem and associated fisheries, as engaged in the two participating communities in the eastern coast of Tanzania. The specific findings are therefore limited by the case boundaries, but the methodological process could be replicated and used elsewhere. The study’s contributions are theoretical and methodological, but also social and practice‐centred. The study brings into view the need to consider the contextual relevance of adapted knowledge, the capacity or ability of beneficiaries to adapt and apply scientific models, frameworks or tools, and the potential of local knowledge as an input for enhancing or improving monitoring of mangroves and mangrove‐based fisheries. Finally, the study comes up with a framework of indicators which is regarded by the coastal communities involved in the study as being less reified, more contextually and culturally congruent, and which may potentially be used in detecting environmental trends, threats, changes and conditions of mangrove and fisheries resources, and attract wider social learning processes.
- Full Text:
- Date Issued: 2014
- Authors: Sabai, Daniel
- Date: 2014
- Subjects: Traditional ecological knowledge , Environmental education -- Tanzania , Environmental education -- Study and teaching -- Tanzania , Coastal zone management -- Tanzania , Social learning -- Tanzania , Experiential learning -- Tanzania , Mangrove conservation -- Tanzania , Fishery management -- Tanzania
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1979 , http://hdl.handle.net/10962/d1013060
- Description: This study addresses a core problem that was uncovered in records from coastal management monitoring initiatives on the eastern coast of Tanzania associated with the application and use of coastal monitoring indicators developed by external development partners for the coastal zone. These records suggest that local communities, who are key actors in participatory monitoring of coastal and marine resources, face many challenges associated with adapting and applying the said frameworks of indicators and monitoring plans. These indicators tend to be scientifically abstracted and methodologically reified; given prevailing contextual and socio‐cultural realities amongst them. The research project addresses the following key research question: How can processes of abstraction, conceptualisation, and representation of TEK contribute to the development of coastal management indicators that are less reified, more contextually and culturally congruent, and which may potentially be used by resource users in the wider social learning process of detecting trends, threats, changes and conditions of mangrove and fisheries resources? In response to the contextual problem and the research question, the study employs processes of abstraction and experiential learning techniques to unlock knowledge that local communities have, as an input for underlabouring existing scientific indicators on the Eastern coast of Tanzania. The research is constituted as critical realist case study research, involving two communities on the eastern coast of Tanzania, namely the Moa and the Boma communities (in Mkinga coastal district). Overall, the study involved 37 participants in a series of interviews, focus group discussions, and experiential learning processes using visualised data, and an experiential learning intervention workshop, and follow‐ups over a period of 3 years. The study worked with mangroves and fisheries to provide focus to the case study research and to allow for in‐depth engagement with the assumptions and processes associated with indicators development and use. Through the above mentioned data generation processes, critical realist analysis, and experiential learning processes involving abstraction and representation of traditional ecological knowledge held by mangrove restorers and fishers in the study areas, the study uncovers possible challenges of adapting and applying scientific indicators in participatory monitoring of a mangrove ecosystem. Using ampliative modes of inference for data analysis (induction, abduction and retroduction) and a critical realist scientific explanatory framework known as DRRREI(C) (Resolution, Re‐description, Retrodiction, Elimination, Identification, & Correction) the study suggests a new approach that may lead to the development of a framework of indicators that are less reified, more congruent to users (coastal communities), and likely to attract a wider context‐based social learning which favours epistemological access between scientific institutions (universities inclusive), and local communities. It attempts to establish an interface between knowledge that scientific institutions produce and the potential knowledge that exists in local contexts (traditional ecological knowledge), and seeks to widen and improve knowledge sharing and experiential learning practices that may potentially benefit coastal and marine resources in the study area. As mentioned above, the knowledge and abstraction processes related to the indicators development focussed on the mangrove ecosystem and associated fisheries, as engaged in the two participating communities in the eastern coast of Tanzania. The specific findings are therefore limited by the case boundaries, but the methodological process could be replicated and used elsewhere. The study’s contributions are theoretical and methodological, but also social and practice‐centred. The study brings into view the need to consider the contextual relevance of adapted knowledge, the capacity or ability of beneficiaries to adapt and apply scientific models, frameworks or tools, and the potential of local knowledge as an input for enhancing or improving monitoring of mangroves and mangrove‐based fisheries. Finally, the study comes up with a framework of indicators which is regarded by the coastal communities involved in the study as being less reified, more contextually and culturally congruent, and which may potentially be used in detecting environmental trends, threats, changes and conditions of mangrove and fisheries resources, and attract wider social learning processes.
- Full Text:
- Date Issued: 2014
Challenging desire : performing whiteness in post-apartheid South Africa
- Authors: Smit, Sonja
- Date: 2014
- Subjects: Performance art -- South Africa , Bailey, Brett, 1967- , Cohen, Steven, 1962- , Antwoord (Musical group) , MacGarry, Michael , Eurocentrism -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2164 , http://hdl.handle.net/10962/d1016358
- Description: The central argument of this thesis asserts that in the process of challenging dominant subject positions, such as whiteness, performance creates the possibilities for new or alternative arrangements of desire. It examines how the creative process of desire is forestalled (reified) by habitual representations of whiteness as a privileged position, and proposes that performance can be a valid form of resistance to static conceptions of race and subjectivity. The discussion takes into account how the privilege of whiteness finds representation through forms of neo-liberalism and neo-colonialism in the post apartheid context. The analysis focuses on the work of white South African artists whose work offers a critique from within the privileged “centre” of whiteness. The research is situated within the inter-disciplinary field of performance studies entailing a reading and application of critical texts to the analysis. Alongside this qualitative methodology surfaces a subjective dialogue with the information presented on whiteness. Part Two includes an analysis of Steven Cohen’s The Cradle of Humankind (2011), Brett Bailey’s Exhibit A (2011) and Michael MacGarry’s LHR-JNB (2010). Each section examines the way in which the respective works engage in a questioning of whiteness through performance. Part Three investigates South African rap-rave duo, Die Antwoord and how their appropriation of Zef interrogates desires for an essential authenticity. Part Four focuses on my own performance practice and the proposed value of engaging with a form of practice-led research. This is particularly relevant in relation to critical race studies that require a level of self-reflexivity from the researcher. It presents an analysis of the work entitled Villain (2012) as a disturbance of theatrical desire through a process of ‘becoming’. This notion of meaning and identity as ‘becoming’ is argued as a strategy to challenge prevailing modes of perception which can possibly restore the production of desire to the viewer. The thesis concludes with the notion that performance can offer a mode of immanent ethics which is significant in creating both vulnerable and critical forms of whiteness.
- Full Text:
- Date Issued: 2014
- Authors: Smit, Sonja
- Date: 2014
- Subjects: Performance art -- South Africa , Bailey, Brett, 1967- , Cohen, Steven, 1962- , Antwoord (Musical group) , MacGarry, Michael , Eurocentrism -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2164 , http://hdl.handle.net/10962/d1016358
- Description: The central argument of this thesis asserts that in the process of challenging dominant subject positions, such as whiteness, performance creates the possibilities for new or alternative arrangements of desire. It examines how the creative process of desire is forestalled (reified) by habitual representations of whiteness as a privileged position, and proposes that performance can be a valid form of resistance to static conceptions of race and subjectivity. The discussion takes into account how the privilege of whiteness finds representation through forms of neo-liberalism and neo-colonialism in the post apartheid context. The analysis focuses on the work of white South African artists whose work offers a critique from within the privileged “centre” of whiteness. The research is situated within the inter-disciplinary field of performance studies entailing a reading and application of critical texts to the analysis. Alongside this qualitative methodology surfaces a subjective dialogue with the information presented on whiteness. Part Two includes an analysis of Steven Cohen’s The Cradle of Humankind (2011), Brett Bailey’s Exhibit A (2011) and Michael MacGarry’s LHR-JNB (2010). Each section examines the way in which the respective works engage in a questioning of whiteness through performance. Part Three investigates South African rap-rave duo, Die Antwoord and how their appropriation of Zef interrogates desires for an essential authenticity. Part Four focuses on my own performance practice and the proposed value of engaging with a form of practice-led research. This is particularly relevant in relation to critical race studies that require a level of self-reflexivity from the researcher. It presents an analysis of the work entitled Villain (2012) as a disturbance of theatrical desire through a process of ‘becoming’. This notion of meaning and identity as ‘becoming’ is argued as a strategy to challenge prevailing modes of perception which can possibly restore the production of desire to the viewer. The thesis concludes with the notion that performance can offer a mode of immanent ethics which is significant in creating both vulnerable and critical forms of whiteness.
- Full Text:
- Date Issued: 2014
Direct and indirect effects of zooplanktivorous predators on the estuarine plankton community
- Authors: Wasserman, Ryan John
- Date: 2014
- Subjects: Zooplankton -- Effect of predation on , Predation (Biology) , Zooplankton -- Predators of , Copepoda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5870 , http://hdl.handle.net/10962/d1012938
- Description: Although predation has been identified as a potentially important driver in terrestrial and freshwater ecosystems, estuarine planktonic research has focused largely on the so-called "bottom-up" drivers of community assemblages. As such, this thesis focuses on the direct and indirect effects of zooplanktivorous predators on the planktonic community in an estuarine environment. By using a suite of in situ mesocosm experiments, a number of hypotheses, pertaining to the major research themes associated with predator-prey interactions, are tested. These themes included trophic cascading, risk effects associated with predation events and the importance of predator diversity in maintaining prey communities. The first experiment assessed the significance of apex predation pressure for the planktonic community through trophic cascades. Various treatments using in situ mesocosms were established in a closed oligotrophic estuary to highlight the importance of predation in stabilising estuarine plankton abundances. Through either the removal (filtration) or addition of certain planktonic groups, varied trophic scenarios were established. The experimental treatment containing apex zooplanktivores had consequences for multiple trophic levels, exerting a stabilising pressure throughout the food web (Chapter 3). Furthermore, pyrosequencing of filtered water samples revealed that when compared to the remaining treatments, the treatment containing stable apex predatory pressure experienced limited temporal deviation-from-initial in bacterial community structure (Chapter 4). These findings are consistent with trophic cascade theory whereby predators mediate interactions at multiple lower trophic levels with consequent repercussions for diversity. To assess the non-consumptive effects of predators on prey, two experiments were conducted. Firstly, using egg numbers per clutch as a measure of potential reproductive output, the non-lethal effects of predatory pressure on reproductive success in a key planktonic copepod was investigated. In this study, the average clutch size of fecund female copepods was found to be consistently lower in the presence of predators when compared to females not exposed to predation threat (Chapter 5). The second study assessed the effects of conspecific chemical alarm cues associated with predation, on population dynamics of a copepod species. This study revealed that the copepods appear to detect the presence of chemical alarm cues associated with predation events, with repercussions for population demographics over time. Furthermore, it showed that in the absence of actual predation, copepod prey responses to alarm cues were adjusted over time, consistent with the threat sensitive predator avoidance hypothesis (Chapter 6). The final data chapter dealt with predator diversity and its implications for zooplankton community structure. By experimentally monitoring the effects of two alternate model predators on the metazoan community over time, dissimilarities in community level control emerged. Alternate key prey populations were regulated by the different model predators, highlighting the importance of predator and prey behaviour in mediating predator-prey interactions (Chapter 7). These results highlight the potential importance of predators in maintaining community dynamics in estuarine planktonic communities under certain conditions. This study represents some of the first work to address these various aspects of predator-prey dynamics within the context of planktonic estuarine ecology.
- Full Text:
- Date Issued: 2014
- Authors: Wasserman, Ryan John
- Date: 2014
- Subjects: Zooplankton -- Effect of predation on , Predation (Biology) , Zooplankton -- Predators of , Copepoda
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5870 , http://hdl.handle.net/10962/d1012938
- Description: Although predation has been identified as a potentially important driver in terrestrial and freshwater ecosystems, estuarine planktonic research has focused largely on the so-called "bottom-up" drivers of community assemblages. As such, this thesis focuses on the direct and indirect effects of zooplanktivorous predators on the planktonic community in an estuarine environment. By using a suite of in situ mesocosm experiments, a number of hypotheses, pertaining to the major research themes associated with predator-prey interactions, are tested. These themes included trophic cascading, risk effects associated with predation events and the importance of predator diversity in maintaining prey communities. The first experiment assessed the significance of apex predation pressure for the planktonic community through trophic cascades. Various treatments using in situ mesocosms were established in a closed oligotrophic estuary to highlight the importance of predation in stabilising estuarine plankton abundances. Through either the removal (filtration) or addition of certain planktonic groups, varied trophic scenarios were established. The experimental treatment containing apex zooplanktivores had consequences for multiple trophic levels, exerting a stabilising pressure throughout the food web (Chapter 3). Furthermore, pyrosequencing of filtered water samples revealed that when compared to the remaining treatments, the treatment containing stable apex predatory pressure experienced limited temporal deviation-from-initial in bacterial community structure (Chapter 4). These findings are consistent with trophic cascade theory whereby predators mediate interactions at multiple lower trophic levels with consequent repercussions for diversity. To assess the non-consumptive effects of predators on prey, two experiments were conducted. Firstly, using egg numbers per clutch as a measure of potential reproductive output, the non-lethal effects of predatory pressure on reproductive success in a key planktonic copepod was investigated. In this study, the average clutch size of fecund female copepods was found to be consistently lower in the presence of predators when compared to females not exposed to predation threat (Chapter 5). The second study assessed the effects of conspecific chemical alarm cues associated with predation, on population dynamics of a copepod species. This study revealed that the copepods appear to detect the presence of chemical alarm cues associated with predation events, with repercussions for population demographics over time. Furthermore, it showed that in the absence of actual predation, copepod prey responses to alarm cues were adjusted over time, consistent with the threat sensitive predator avoidance hypothesis (Chapter 6). The final data chapter dealt with predator diversity and its implications for zooplankton community structure. By experimentally monitoring the effects of two alternate model predators on the metazoan community over time, dissimilarities in community level control emerged. Alternate key prey populations were regulated by the different model predators, highlighting the importance of predator and prey behaviour in mediating predator-prey interactions (Chapter 7). These results highlight the potential importance of predators in maintaining community dynamics in estuarine planktonic communities under certain conditions. This study represents some of the first work to address these various aspects of predator-prey dynamics within the context of planktonic estuarine ecology.
- Full Text:
- Date Issued: 2014
Trophic relationships of hake (Merluccius capensis Castelnau, 1851 and M. paradoxus Franca 1960) from the Northern Benguela current ecosystem (Namibia) : inferences from stable isotopes and fatty acids
- Authors: Iitembu, Johannes Angala
- Date: 2014
- Subjects: Hake -- Benguela Current , Merlucciidae -- Benguela Current , Multitrophic interactions (Ecology) , Food chains (Ecology) , Biotic communities -- Benguela Current , Merlucciidae -- Food , Fishery management -- Namibia , Stable isotopes , Fatty acids
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5944 , http://hdl.handle.net/10962/d1020296
- Description: Two species of hake (Merluccius capensis and Merluccius paradoxus) account for most of Namibia’s fisheries catch, and they are important secondary consumers in the Benguela Current ecosystem. Inferences on their trophic relationships have been based mainly on stomach content analyses. However, such data are limited temporally because they represent only snapshots of recent feeding, and are quantitatively biased because of variation in the digestion rates of different prey. The principal aim of the thesis was to understand the trophic relationships of two hake species relative to each other, their known prey and top predators (demersal sharks) in the northern Benguela Current ecosystem (Namibia), using time-integrating trophic biomarkers. By using stable isotope (carbon and nitrogen) and fatty acid signatures of their muscle tissues, my overall objectives were to produce new knowledge about 1) hake ontogenic trophic relationships, 2) the contributions of different prey to hake diets, 3) hake dietary differences, and 4) some aspects of hake’s trophic relationships with demersal sharks. Tissues of hake (n=358), their potential prey (n=455), and demersal sharks (n=42) were collected between 2008 and 2012 during demersal bottom trawl surveys off Namibia, for stable isotope and fatty acid analyses. And more...
- Full Text:
- Date Issued: 2014
- Authors: Iitembu, Johannes Angala
- Date: 2014
- Subjects: Hake -- Benguela Current , Merlucciidae -- Benguela Current , Multitrophic interactions (Ecology) , Food chains (Ecology) , Biotic communities -- Benguela Current , Merlucciidae -- Food , Fishery management -- Namibia , Stable isotopes , Fatty acids
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5944 , http://hdl.handle.net/10962/d1020296
- Description: Two species of hake (Merluccius capensis and Merluccius paradoxus) account for most of Namibia’s fisheries catch, and they are important secondary consumers in the Benguela Current ecosystem. Inferences on their trophic relationships have been based mainly on stomach content analyses. However, such data are limited temporally because they represent only snapshots of recent feeding, and are quantitatively biased because of variation in the digestion rates of different prey. The principal aim of the thesis was to understand the trophic relationships of two hake species relative to each other, their known prey and top predators (demersal sharks) in the northern Benguela Current ecosystem (Namibia), using time-integrating trophic biomarkers. By using stable isotope (carbon and nitrogen) and fatty acid signatures of their muscle tissues, my overall objectives were to produce new knowledge about 1) hake ontogenic trophic relationships, 2) the contributions of different prey to hake diets, 3) hake dietary differences, and 4) some aspects of hake’s trophic relationships with demersal sharks. Tissues of hake (n=358), their potential prey (n=455), and demersal sharks (n=42) were collected between 2008 and 2012 during demersal bottom trawl surveys off Namibia, for stable isotope and fatty acid analyses. And more...
- Full Text:
- Date Issued: 2014
Nonlinear optical studies of metallophtalocyanines and hemiporphyrazines in solution
- Authors: Britton, Jonathan
- Date: 2014
- Subjects: Phthalocyanines Photochemistry Nanoparticles Nanostructured materials Polymers Quantum dots
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4464 , http://hdl.handle.net/10962/d1011608
- Description: This thesis presents the study of the effects of CdTe-TGA quantum dots (QDs) on optical limiting ability of different phthalocyanine (Pc) complexes (5-12) containing Zn, Ga, In central metals and substituted with benzyloxyphenoxy, phenoxy, tertbutylphenoxy and amino groups in solution and in poly (methyl methacrylate) (PMMA) films. The optical limiting parameters of Pcs were higher for tertbutylphenoxy when compared to benzyloxyphenoxy and phenoxy substituents, in DMSO. Non-peripheral substitution decreased the optical limiting parameters. Third-order susceptibility (Im[χ⁽³⁾]/α) values of Pcs in the absence and presence of CdTe QDs were in the 10⁻¹² to 10⁻¹° esu cm range. Hyperpolarizabilities (γ) ranged from 10⁻³¹ to 10⁻²⁹ esu L for Pc alone or in mixture with QDs. The effect on the optical limiting abilities of twelve embedded phthalocyanines containing In, Ga, Zn and Al as central metals in polymer thin films was also examined. The effect of forming a covalent link zinc tetraamino phthalocyanine (12) with poly (methyl acrylic acid) (PMAA) and Zn (13) and OHAl (14) octacarboxy phthalocyanines to polyethylenimine (PEI) was also studied. The hyperpolarizability of the twelve phthalocyanines in polymer was found to be in the range of 10⁻²⁶ to 10⁻²⁴ esu.L. This is significantly higher than the hyperpolarizabilities of these phthalocyanines in solution. Non-linear optical (NLO) parameters were determined for phthalocyanine complexes containing In, Ga and Zn as central metals when embedded in PMMA polymer in the presence of quantum dots (QDs). The QDs mainly employed were CdTe-TGA (TGA = thioglylcolic acid). Triplet lifetimes increased as k (excited state (σex) to ground state (σg) absorption cross section ratio) values decreased with the addition of the CdTe-TGA to the phthalocyanines. The saturation energy density (Fsat) values were smaller in the films when compared to the solutions. Complex 7 tetrasubstituted with tert-butylphenoxy groups at non-peripheral positions was also studied in the presence of CdS-TGA, CdSe-TGA, fullerenes and single walled carbon nanotubes. There is a general improvement in optical limiting ability of Pc complexes in the presence of nanomaterials (NMs). Degradation studies seem to indicate that placing a phthalocyanine within a polymer thin film may protect it slightly from photo- and thermal degradation. 3(4), 15(16)-Bis-(4 -tert-butyl-phenoxy)-10, 22-diaminohemiporphyrazinato chloroindium hemiporphyrazine was synthesized from 1, 3, 5-triaminobenzene and 4-tert-butyl-phenoxyisoindoline. The structure of the complex was confirmed using mass, nuclear magnetic resonance and infrared spectroscopies. The nonlinear parameters of the compound was also analyzed in dimethylformamide and found to be significantly greater than previously analyzed phthalocyanines.
- Full Text:
- Date Issued: 2014
- Authors: Britton, Jonathan
- Date: 2014
- Subjects: Phthalocyanines Photochemistry Nanoparticles Nanostructured materials Polymers Quantum dots
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4464 , http://hdl.handle.net/10962/d1011608
- Description: This thesis presents the study of the effects of CdTe-TGA quantum dots (QDs) on optical limiting ability of different phthalocyanine (Pc) complexes (5-12) containing Zn, Ga, In central metals and substituted with benzyloxyphenoxy, phenoxy, tertbutylphenoxy and amino groups in solution and in poly (methyl methacrylate) (PMMA) films. The optical limiting parameters of Pcs were higher for tertbutylphenoxy when compared to benzyloxyphenoxy and phenoxy substituents, in DMSO. Non-peripheral substitution decreased the optical limiting parameters. Third-order susceptibility (Im[χ⁽³⁾]/α) values of Pcs in the absence and presence of CdTe QDs were in the 10⁻¹² to 10⁻¹° esu cm range. Hyperpolarizabilities (γ) ranged from 10⁻³¹ to 10⁻²⁹ esu L for Pc alone or in mixture with QDs. The effect on the optical limiting abilities of twelve embedded phthalocyanines containing In, Ga, Zn and Al as central metals in polymer thin films was also examined. The effect of forming a covalent link zinc tetraamino phthalocyanine (12) with poly (methyl acrylic acid) (PMAA) and Zn (13) and OHAl (14) octacarboxy phthalocyanines to polyethylenimine (PEI) was also studied. The hyperpolarizability of the twelve phthalocyanines in polymer was found to be in the range of 10⁻²⁶ to 10⁻²⁴ esu.L. This is significantly higher than the hyperpolarizabilities of these phthalocyanines in solution. Non-linear optical (NLO) parameters were determined for phthalocyanine complexes containing In, Ga and Zn as central metals when embedded in PMMA polymer in the presence of quantum dots (QDs). The QDs mainly employed were CdTe-TGA (TGA = thioglylcolic acid). Triplet lifetimes increased as k (excited state (σex) to ground state (σg) absorption cross section ratio) values decreased with the addition of the CdTe-TGA to the phthalocyanines. The saturation energy density (Fsat) values were smaller in the films when compared to the solutions. Complex 7 tetrasubstituted with tert-butylphenoxy groups at non-peripheral positions was also studied in the presence of CdS-TGA, CdSe-TGA, fullerenes and single walled carbon nanotubes. There is a general improvement in optical limiting ability of Pc complexes in the presence of nanomaterials (NMs). Degradation studies seem to indicate that placing a phthalocyanine within a polymer thin film may protect it slightly from photo- and thermal degradation. 3(4), 15(16)-Bis-(4 -tert-butyl-phenoxy)-10, 22-diaminohemiporphyrazinato chloroindium hemiporphyrazine was synthesized from 1, 3, 5-triaminobenzene and 4-tert-butyl-phenoxyisoindoline. The structure of the complex was confirmed using mass, nuclear magnetic resonance and infrared spectroscopies. The nonlinear parameters of the compound was also analyzed in dimethylformamide and found to be significantly greater than previously analyzed phthalocyanines.
- Full Text:
- Date Issued: 2014
An investigation into the development of knowledge and strategies for the teaching of visual literacy in under-resourced Eastern Cape schools
- Authors: Mbelani, Madeyandile
- Date: 2014
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64401 , vital:28540
- Description: This thesis reports on a multiple case study PhD project that aimed to investigate meaningful and critical development of knowledge and strategies to teach visual literacy, a component of English First Additional Language (FAL) in six under-resourced schools of the Eastern Cape of South Africa. The study begins by locating visual literacy within a broad framework of literacy as a social practice, and discusses its importance. Further, it discusses complexities of making sense of and teaching visual literacy, especially for the majority of in-service teachers who experienced visual literacy neither as learners nor as teacher trainees. The gap between the curriculum and teachers’ classroom practices is what triggered this study to adopt a transformative paradigm. The main research question is, “How can teacher professional development in English Language Teaching advance in-service teachers’ knowledge of and strategies for meaningful and critical teaching and learning of visual literacy?” To respond to this question, I drew on cultural historical activity theory (CHAT) and critical realism (CR) to design four phases of this study that incorporated the seven stages of an expansive learning cycle. These phases focussed on exploring and expanding teachers’ sense making and teaching of visual literacy. I collected data through interviews, document analysis, videoed lessons and change laboratory (CL) workshops. I designed a data analysis tool that brought together CHAT, CR, multimodal social semiotics, critical discourse analysis and pedagogical discourse to make sense of the data. Through a process of reflexivity, the study illuminated layers of factors that constrained meaningful and critical teaching of visual literacy in the empirical, the actual and the real domains of reality. These factors include teachers’ unconscious reproduction of discourses of domination, their intolerance of diverse cultural discourses, resistance to curriculum change, and the fact that they are comfortable with the status quo. I brought these factors to CL workshops for expansive learning. The study contributes in-depth insight into English FAL in-service teacher development in the area of visual literacy. By locating the study within meaning making and teaching of visual literacy, it was possible to interrogate access, diversity, domination and design in teachers’ classroom practices. As a result of this study participants were made aware of the extent to which these factors enabled or hindered meaningful and critical teaching. Participants repositioned themselves as subjects of the activity system, thereby mobilising their agency to take control of the structures and cultures that condition their teaching.
- Full Text:
- Date Issued: 2014
- Authors: Mbelani, Madeyandile
- Date: 2014
- Subjects: Uncatalogued
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/64401 , vital:28540
- Description: This thesis reports on a multiple case study PhD project that aimed to investigate meaningful and critical development of knowledge and strategies to teach visual literacy, a component of English First Additional Language (FAL) in six under-resourced schools of the Eastern Cape of South Africa. The study begins by locating visual literacy within a broad framework of literacy as a social practice, and discusses its importance. Further, it discusses complexities of making sense of and teaching visual literacy, especially for the majority of in-service teachers who experienced visual literacy neither as learners nor as teacher trainees. The gap between the curriculum and teachers’ classroom practices is what triggered this study to adopt a transformative paradigm. The main research question is, “How can teacher professional development in English Language Teaching advance in-service teachers’ knowledge of and strategies for meaningful and critical teaching and learning of visual literacy?” To respond to this question, I drew on cultural historical activity theory (CHAT) and critical realism (CR) to design four phases of this study that incorporated the seven stages of an expansive learning cycle. These phases focussed on exploring and expanding teachers’ sense making and teaching of visual literacy. I collected data through interviews, document analysis, videoed lessons and change laboratory (CL) workshops. I designed a data analysis tool that brought together CHAT, CR, multimodal social semiotics, critical discourse analysis and pedagogical discourse to make sense of the data. Through a process of reflexivity, the study illuminated layers of factors that constrained meaningful and critical teaching of visual literacy in the empirical, the actual and the real domains of reality. These factors include teachers’ unconscious reproduction of discourses of domination, their intolerance of diverse cultural discourses, resistance to curriculum change, and the fact that they are comfortable with the status quo. I brought these factors to CL workshops for expansive learning. The study contributes in-depth insight into English FAL in-service teacher development in the area of visual literacy. By locating the study within meaning making and teaching of visual literacy, it was possible to interrogate access, diversity, domination and design in teachers’ classroom practices. As a result of this study participants were made aware of the extent to which these factors enabled or hindered meaningful and critical teaching. Participants repositioned themselves as subjects of the activity system, thereby mobilising their agency to take control of the structures and cultures that condition their teaching.
- Full Text:
- Date Issued: 2014
The development of functionalized electrospun nanofibers for the control of pathogenic microorganisms in water.
- Authors: Kleyi, Phumelele Eldridge
- Date: 2014
- Subjects: Electrospinning , Nanofibers , Pathogenic microorganisms , Pathogenic microorganisms -- Detection , Drinking water -- Microbiology , Water quality -- Measurement , Imidazoles , Spectrum analysis , Anti-infective agents , Polymerization
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4497 , http://hdl.handle.net/10962/d1013134
- Description: The thesis presents the development of functionalized electrospun nylon 6 nanofibers for the eradication of pathogenic microorganisms in drinking water. Imidazole derivatives were synthesized as the antimicrobial agents and were characterized by means of NMR spectroscopy, IR spectroscopy, elemental analysis and X-ray crystallography. The first set of compounds (2-substituted N-alkylimidazoles) consisted of imidazole derivatives substituted with different alkyl groups (methyl, ethyl, propyl, butyl, heptyl, octyl, decyl and benzyl) at the 1-position and various functional groups [carboxaldehyde (CHO), alcohol (CH2OH) and carboxylic acid (COOH)] at the 2-position. It was observed that the antimicrobial activity of the compounds increased with increasing alkyl chain length and decreasing pKa of the 2-substituent. It was also observed that the antimicrobial activity was predominantly against a Gram-positive bacterial strains [Staphylococcus aureus (MIC = 5-160 μg/mL) and Bacillus subtilis subsp. spizizenii (MIC = 5-20 μg/mL)], with the latter being the more susceptible. However, the compounds displayed poor antimicrobial activity against Gram-negative bacterial strain, E. coli (MIC = 150- >2500 μg/mL) and did not show any activity against the yeast, C. albicans. The second set of compounds consisted of the silver(I) complexes containing 2-hydroxymethyl-N-alkylimidazoles. The complexes displayed a broad spectrum antimicrobial activity towards the microorganisms that were tested and their activity [E. coli (MIC = 5-40 μg/mL), S. aureus (MIC = 20-80 μg/mL), Bacillus subtilis subsp. spizizenii (MIC = 5-40 μg/mL) and C. albicans (MIC = 40-80 μg/mL)] increased with the alkyl chain length of the 2-hydroxymethyl-N-alkylimidazole. The third set of compounds consisted of the vinylimidazoles containing the vinyl group either at the 1-position or at the 4- or 5- position. The imidazoles with the vinyl group at the 4- or 5-position contained the alkyl group (decyl) at the 1-position. For the fabrication of the antimicrobial nanofibers, the first two sets of imidazole derivatives (2-substituted N-alkylimidazoles and silver(I) complexes) were incorporated into electrospun nylon 6 nanofibers while the third set (2-substituted vinylimidazoles) was immobilized onto electrospun nylon 6 nanofibers employing the graft polymerization method. The antimicrobial nylon nanofibers were characterized by IR spectroscopy and SEM-EDAX (EDS). The electrospun nylon 6 nanofibers incorporated with 2-substituted N-alkylimidazoles displayed moderate to excellent levels of growth reduction against S. aureus (73.2-99.8 percent). For the electrospun nylon 6 nanofibers incorporated with silver(I) complexes, the levels of growth reduction were >99.99 percent, after the antimicrobial activity evaluation using the shake flask method. Furthermore, the grafted electrospun nylon 6 nanofibers showed excellent levels of growth reduction for E. coli (99.94-99.99 percent) and S. aureus (99.93-99.99 percent). The reusability results indicated that the grafted electrospun nylon 6 nanofibers maintained the antibacterial activity until the third cycle of useage. The cytotoxicity studies showed that grafted electrospun nylon 6 nanofibers possess lower cytotoxic effects on Chang liver cells with IC50 values in the range 23.48-26.81 μg/mL. The thesis demonstrated that the development of antimicrobial electrospun nanofibers, with potential for the eradication of pathogenic microoganisms in water, could be accomplished by incorporation as well as immobilization strategies.
- Full Text:
- Date Issued: 2014
- Authors: Kleyi, Phumelele Eldridge
- Date: 2014
- Subjects: Electrospinning , Nanofibers , Pathogenic microorganisms , Pathogenic microorganisms -- Detection , Drinking water -- Microbiology , Water quality -- Measurement , Imidazoles , Spectrum analysis , Anti-infective agents , Polymerization
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4497 , http://hdl.handle.net/10962/d1013134
- Description: The thesis presents the development of functionalized electrospun nylon 6 nanofibers for the eradication of pathogenic microorganisms in drinking water. Imidazole derivatives were synthesized as the antimicrobial agents and were characterized by means of NMR spectroscopy, IR spectroscopy, elemental analysis and X-ray crystallography. The first set of compounds (2-substituted N-alkylimidazoles) consisted of imidazole derivatives substituted with different alkyl groups (methyl, ethyl, propyl, butyl, heptyl, octyl, decyl and benzyl) at the 1-position and various functional groups [carboxaldehyde (CHO), alcohol (CH2OH) and carboxylic acid (COOH)] at the 2-position. It was observed that the antimicrobial activity of the compounds increased with increasing alkyl chain length and decreasing pKa of the 2-substituent. It was also observed that the antimicrobial activity was predominantly against a Gram-positive bacterial strains [Staphylococcus aureus (MIC = 5-160 μg/mL) and Bacillus subtilis subsp. spizizenii (MIC = 5-20 μg/mL)], with the latter being the more susceptible. However, the compounds displayed poor antimicrobial activity against Gram-negative bacterial strain, E. coli (MIC = 150- >2500 μg/mL) and did not show any activity against the yeast, C. albicans. The second set of compounds consisted of the silver(I) complexes containing 2-hydroxymethyl-N-alkylimidazoles. The complexes displayed a broad spectrum antimicrobial activity towards the microorganisms that were tested and their activity [E. coli (MIC = 5-40 μg/mL), S. aureus (MIC = 20-80 μg/mL), Bacillus subtilis subsp. spizizenii (MIC = 5-40 μg/mL) and C. albicans (MIC = 40-80 μg/mL)] increased with the alkyl chain length of the 2-hydroxymethyl-N-alkylimidazole. The third set of compounds consisted of the vinylimidazoles containing the vinyl group either at the 1-position or at the 4- or 5- position. The imidazoles with the vinyl group at the 4- or 5-position contained the alkyl group (decyl) at the 1-position. For the fabrication of the antimicrobial nanofibers, the first two sets of imidazole derivatives (2-substituted N-alkylimidazoles and silver(I) complexes) were incorporated into electrospun nylon 6 nanofibers while the third set (2-substituted vinylimidazoles) was immobilized onto electrospun nylon 6 nanofibers employing the graft polymerization method. The antimicrobial nylon nanofibers were characterized by IR spectroscopy and SEM-EDAX (EDS). The electrospun nylon 6 nanofibers incorporated with 2-substituted N-alkylimidazoles displayed moderate to excellent levels of growth reduction against S. aureus (73.2-99.8 percent). For the electrospun nylon 6 nanofibers incorporated with silver(I) complexes, the levels of growth reduction were >99.99 percent, after the antimicrobial activity evaluation using the shake flask method. Furthermore, the grafted electrospun nylon 6 nanofibers showed excellent levels of growth reduction for E. coli (99.94-99.99 percent) and S. aureus (99.93-99.99 percent). The reusability results indicated that the grafted electrospun nylon 6 nanofibers maintained the antibacterial activity until the third cycle of useage. The cytotoxicity studies showed that grafted electrospun nylon 6 nanofibers possess lower cytotoxic effects on Chang liver cells with IC50 values in the range 23.48-26.81 μg/mL. The thesis demonstrated that the development of antimicrobial electrospun nanofibers, with potential for the eradication of pathogenic microoganisms in water, could be accomplished by incorporation as well as immobilization strategies.
- Full Text:
- Date Issued: 2014
Synthetic analogues of marine bisindole alkaloids as potent selective inhibitors of MRSA pyruvate kinase
- Veale, Clinton Gareth Lancaster
- Authors: Veale, Clinton Gareth Lancaster
- Date: 2014 , 2014-04-02
- Subjects: Alkaloids , Pyruvate kinase , Staphylococcus aureus , Antibiotics , Sponges -- South Africa , Imidazoles , Biological assay , Antibacterial agents
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4563 , http://hdl.handle.net/10962/d1020893
- Description: Globally, methicillin resistant Staphylococcus aureus (MRSA) has become increasingly difficult to manage in the clinic and new antibiotics are required. The structure activity relationship (SAR) study presented in this thesis forms part of an international collaborative effort to identify potent and selective inhibitors of an MRSA pyruvate kinase (PK) enzyme target. In earlier work the known marine natural product bromodeoxytopsentin (1.6), isolated from a South African marine sponge Topsentia pachastrelloides, exhibited selective and significant inhibition of MRSA PK (IC₅₀ 60 nM). Accordingly bromodeoxytopsentin provided the initial chemical scaffold around which our SAR study was developed. Following a comprehensive introduction, providing the necessary background to the research described in subsequent Chapters, this thesis has been divided into three major parts. Part one (Chapter 2) documents the synthesis of two natural imidazole containing topsentin analogues 1.40, 1.46, five new synthetic analogues 1.58—1.61, 2.104. In the process we developed a new method for the synthesis of topsentin derivatives via selenium dioxide mediated oxidation of N-Boc protected 3-acetylindoles to yield glyoxal intermediates which were subsequently cyclized and deprotected to yield the desired products. Interestingly we were able to demonstrate a delicate relationship between the relative equivalents of selenium dioxide and water used during the oxidation step, careful manipulation of which was required to prevent the uncontrolled formation of side products. Synthetic compounds 1.40, 1.46, 1.58—1.61 were found to be potent inhibitors of MRSA PK (IC₅₀ 238, 2.1, 23, 1.4, 6.3 and 3.2 nM respectively) with 1000-10000 fold selectivity for MRSA PK over four human orthologs. In the second part of this thesis (Chapter 3) we report the successful synthesis of a cohort of previously unknown thiazole containing bisindole topsentin analogues 1.62—1.68 via a Hantzsch thiazole synthesis. Bioassay results revealed that these compounds were only moderate inhibitors of MRSA PK (IC₅₀ 5.1—20 μM) which suggested that inhibitory activity was significantly reduced upon substitution of the central imidazole ring of topsentin type analogues with a thiazole type ring. In addition in Chapter 3 we describe unsuccessful attempts to regiospecifically synthesize oxazole and imidazole topsentin analogues through a similar Hantzsch method. As a consequence of our efforts in this regard we investigated three key reactions in depth, namely the synthesis of 2.2, 3.38, 3.40, 3.41 via α-bromination of 3-acetylindole and the synthesis of indolyl-3-carbonylnitriles 2.13, 3.45—3.47 and α-oxo-1H-indole-3-thioacetamides 3.48—3.51. The investigation of the latter led to the isolation and elucidation of two anomalous N,N-dimethyl-1H-indole-3-carboxamides 3.52 and 3.53. Finally the third part of this thesis (Chapter 4) deals with in silico assessment of the binding of both the imidazole and thiazole containing bisindole alkaloids to the MRSA PK protein which initially guided our SAR studies. In this chapter we reveal that there appears to be no correlation between in silico binding predictions and in vitro MRSA PK inhibitory bioassay data. Superficially it seems that binding energy as determined by the docking program used for these studies correlated with the size of the indole substituents and did not reflect IC₅₀ MRSA PK inhibitory data. Although this led us to computationally explore possible alternative binding sites no clear alternative has been identified.
- Full Text:
- Date Issued: 2014
- Authors: Veale, Clinton Gareth Lancaster
- Date: 2014 , 2014-04-02
- Subjects: Alkaloids , Pyruvate kinase , Staphylococcus aureus , Antibiotics , Sponges -- South Africa , Imidazoles , Biological assay , Antibacterial agents
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4563 , http://hdl.handle.net/10962/d1020893
- Description: Globally, methicillin resistant Staphylococcus aureus (MRSA) has become increasingly difficult to manage in the clinic and new antibiotics are required. The structure activity relationship (SAR) study presented in this thesis forms part of an international collaborative effort to identify potent and selective inhibitors of an MRSA pyruvate kinase (PK) enzyme target. In earlier work the known marine natural product bromodeoxytopsentin (1.6), isolated from a South African marine sponge Topsentia pachastrelloides, exhibited selective and significant inhibition of MRSA PK (IC₅₀ 60 nM). Accordingly bromodeoxytopsentin provided the initial chemical scaffold around which our SAR study was developed. Following a comprehensive introduction, providing the necessary background to the research described in subsequent Chapters, this thesis has been divided into three major parts. Part one (Chapter 2) documents the synthesis of two natural imidazole containing topsentin analogues 1.40, 1.46, five new synthetic analogues 1.58—1.61, 2.104. In the process we developed a new method for the synthesis of topsentin derivatives via selenium dioxide mediated oxidation of N-Boc protected 3-acetylindoles to yield glyoxal intermediates which were subsequently cyclized and deprotected to yield the desired products. Interestingly we were able to demonstrate a delicate relationship between the relative equivalents of selenium dioxide and water used during the oxidation step, careful manipulation of which was required to prevent the uncontrolled formation of side products. Synthetic compounds 1.40, 1.46, 1.58—1.61 were found to be potent inhibitors of MRSA PK (IC₅₀ 238, 2.1, 23, 1.4, 6.3 and 3.2 nM respectively) with 1000-10000 fold selectivity for MRSA PK over four human orthologs. In the second part of this thesis (Chapter 3) we report the successful synthesis of a cohort of previously unknown thiazole containing bisindole topsentin analogues 1.62—1.68 via a Hantzsch thiazole synthesis. Bioassay results revealed that these compounds were only moderate inhibitors of MRSA PK (IC₅₀ 5.1—20 μM) which suggested that inhibitory activity was significantly reduced upon substitution of the central imidazole ring of topsentin type analogues with a thiazole type ring. In addition in Chapter 3 we describe unsuccessful attempts to regiospecifically synthesize oxazole and imidazole topsentin analogues through a similar Hantzsch method. As a consequence of our efforts in this regard we investigated three key reactions in depth, namely the synthesis of 2.2, 3.38, 3.40, 3.41 via α-bromination of 3-acetylindole and the synthesis of indolyl-3-carbonylnitriles 2.13, 3.45—3.47 and α-oxo-1H-indole-3-thioacetamides 3.48—3.51. The investigation of the latter led to the isolation and elucidation of two anomalous N,N-dimethyl-1H-indole-3-carboxamides 3.52 and 3.53. Finally the third part of this thesis (Chapter 4) deals with in silico assessment of the binding of both the imidazole and thiazole containing bisindole alkaloids to the MRSA PK protein which initially guided our SAR studies. In this chapter we reveal that there appears to be no correlation between in silico binding predictions and in vitro MRSA PK inhibitory bioassay data. Superficially it seems that binding energy as determined by the docking program used for these studies correlated with the size of the indole substituents and did not reflect IC₅₀ MRSA PK inhibitory data. Although this led us to computationally explore possible alternative binding sites no clear alternative has been identified.
- Full Text:
- Date Issued: 2014
"I felt that I deserved it" : an Investigation into HIV-related PTSD, traumatic life events, and the personal experiences of living with HIV : a mixed-method study
- Authors: Boulind, Melissa Jane
- Date: 2014
- Subjects: Post-traumatic stress disorder -- Psychological aspects -- Research -- South Africa -- Kwazulu HIV infections -- Psychological aspects -- Research -- South Africa -- Kwazulu HIV-positive persons -- South Africa -- Kwazulu -- Interviews Psychic trauma -- Research Stress (Psychology) -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3211 , http://hdl.handle.net/10962/d1012172
- Description: There appears to be a growing body of literature focusing on PTSD and HIV-related PTSD (the diagnosis of HIV being the significant traumatic event) amongst HIV-positive samples, but only a few African studies that attempt to estimate the prevalence of PTSD amongst HIV-positive people, and even fewer that attempt to estimate the prevalence of HIV-related PTSD. The systemic review presented in this study is currently fully inclusive and is the most up-to-date available. Estimates of the prevalence of PTSD and HIV-related PTSD in South Africa range from 0.7 to 54.1% and, 4.2 to 40% respectively. The current cross-sectional study made use of a mixed-method approach to investigate traumatic life events, PTSD and HIV-related PTSD within a primary health-care centre in KwaZulu-Natal. The quantitative sample consisted of 159 adults (18-50 years) who were compliant on ARV medication. Using the CIDI-PTSD module, the adapted CIDI-PTSD module for HIV, and IES-R, findings indicated that 62% had reported some kind of traumatic event in their lifetime, with 29.6% of participants meeting the criteria for lifetime PTSD, and 40.9% meeting the criteria for lifetime HIV-related PTSD. Altogether, 57.9% of individuals met the criteria for some form of PTSD (either regular PTSD or HIV-related PTSD), and 12.6% met the criteria for both PTSD and HIV-related PTSD. Of the different categories of traumatic events, interpersonal violence has the highest rate of PTSD, followed by a diagnosis of and living with HIV, and then disaster. Furthermore, the IES-R was compared for its usefulness as a screening measure for PTSD against both the CIDI, but results suggest that it is an inferior screening measure to the PDS. The qualitative study consisted of six participants who were examined using IPA methodology informed by the Ehlers and Clark (2000) Model of trauma. Their experiences revealed experiences of stigma, a number of negative appraisals, negative emotions and coping behaviours. Some of the latter might serve as compensatory mechanisms to avoid negative judgements. Hypervigilance seems to be a feature of ARV-compliance that might confer added vulnerability to PTSD and other anxiety disorders.
- Full Text:
- Date Issued: 2014
- Authors: Boulind, Melissa Jane
- Date: 2014
- Subjects: Post-traumatic stress disorder -- Psychological aspects -- Research -- South Africa -- Kwazulu HIV infections -- Psychological aspects -- Research -- South Africa -- Kwazulu HIV-positive persons -- South Africa -- Kwazulu -- Interviews Psychic trauma -- Research Stress (Psychology) -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3211 , http://hdl.handle.net/10962/d1012172
- Description: There appears to be a growing body of literature focusing on PTSD and HIV-related PTSD (the diagnosis of HIV being the significant traumatic event) amongst HIV-positive samples, but only a few African studies that attempt to estimate the prevalence of PTSD amongst HIV-positive people, and even fewer that attempt to estimate the prevalence of HIV-related PTSD. The systemic review presented in this study is currently fully inclusive and is the most up-to-date available. Estimates of the prevalence of PTSD and HIV-related PTSD in South Africa range from 0.7 to 54.1% and, 4.2 to 40% respectively. The current cross-sectional study made use of a mixed-method approach to investigate traumatic life events, PTSD and HIV-related PTSD within a primary health-care centre in KwaZulu-Natal. The quantitative sample consisted of 159 adults (18-50 years) who were compliant on ARV medication. Using the CIDI-PTSD module, the adapted CIDI-PTSD module for HIV, and IES-R, findings indicated that 62% had reported some kind of traumatic event in their lifetime, with 29.6% of participants meeting the criteria for lifetime PTSD, and 40.9% meeting the criteria for lifetime HIV-related PTSD. Altogether, 57.9% of individuals met the criteria for some form of PTSD (either regular PTSD or HIV-related PTSD), and 12.6% met the criteria for both PTSD and HIV-related PTSD. Of the different categories of traumatic events, interpersonal violence has the highest rate of PTSD, followed by a diagnosis of and living with HIV, and then disaster. Furthermore, the IES-R was compared for its usefulness as a screening measure for PTSD against both the CIDI, but results suggest that it is an inferior screening measure to the PDS. The qualitative study consisted of six participants who were examined using IPA methodology informed by the Ehlers and Clark (2000) Model of trauma. Their experiences revealed experiences of stigma, a number of negative appraisals, negative emotions and coping behaviours. Some of the latter might serve as compensatory mechanisms to avoid negative judgements. Hypervigilance seems to be a feature of ARV-compliance that might confer added vulnerability to PTSD and other anxiety disorders.
- Full Text:
- Date Issued: 2014
Understanding and modelling of surface and groundwater interactions
- Authors: Tanner, Jane Louise
- Date: 2014
- Subjects: Groundwater -- South Africa , Water-supply -- Management , Integrated water development , Hydrogeology , Water resources development -- South Africa , Water -- Analysis , Groundwater -- Management , Watersheds -- South Africa , Hydrologic models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6043 , http://hdl.handle.net/10962/d1012994
- Description: The connections between surface water and groundwater systems remain poorly understood in many catchments throughout the world and yet they are fundamental to effectively managing water resources. Managing water resources in an integrated manner is not straightforward, particularly if both resources are being utilised, and especially in those regions that suffer problems of data scarcity. This study explores some of the principle issues associated with understanding and practically modelling surface and groundwater interactions. In South Africa, there remains much controversy over the most appropriate type of integrated model to be used and the way forward in terms of the development of the discipline; part of the disagreement stems from the fact that we cannot validate models adequately. This is largely due to traditional forms of model testing having limited power as it is difficult to differentiate between the uncertainties within different model structures, different sets of alternative parameter values and in the input data used to run the model. While model structural uncertainties are important to consider, the uncertainty from input data error together with parameter estimation error are often more significant to the overall residual error, and essential to consider if we want to achieve reliable predictions for water resource decisions. While new philosophies and theories on modelling and results validation have been developed (Beven, 2002; Gupta et al., 2008), in many cases models are not only still being validated and compared using sparse and uncertain datasets, but also expected to produce reliable predictions based on the flawed data. The approach in this study is focused on fundamental understanding of hydrological systems rather than calibration based modelling and promotes the use of all the available 'hard' and 'soft' data together with thoughtful conceptual examination of the processes occurring in an environment to ensure as far as possible that a model is generating sensible results by simulating the correct processes. The first part of the thesis focuses on characterising the 'typical' interaction environments found in South Africa. It was found that many traditional perceptual models are not necessarily applicable to South African conditions, largely due to the relative importance of unsaturated zone processes and the complexity of the dominantly fractured rock environments. The interaction environments were categorised into four main 'types' of environment. These include karst, primary, fractured rock (secondary), and alluvial environments. Processes critical to Integrated Water Resource Management (IWRM) were defined within each interaction type as a guideline to setting a model up to realistically represent the dominant processes in the respective settings. The second part of the thesis addressed the application and evaluation of the modified Pitman model (Hughes, 2004), which allows for surface and groundwater interaction behaviour at the catchment scale to be simulated. The issue is whether, given the different sources of uncertainty in the modelling process, we can differentiate one conceptual flow path from another in trying to refine the understanding and consequently have more faith in model predictions. Seven example catchments were selected from around South Africa to assess whether reliable integrated assessments can be carried out given the existing data. Specific catchment perceptual models were used to identify the critical processes occurring in each setting and the Pitman model was assessed on whether it could represent them (structural uncertainty). The available knowledge of specific environments or catchments was then examined in an attempt to resolve the parameter uncertainty present within each catchment and ensure the subsequent model setup was correctly representing the process understanding as far as possible. The confidence in the quantitative results inevitably varied with the amount and quality of the data available. While the model was deemed to be robust based on the behavioural results obtained in the majority of the case studies, in many cases a quantitative validation of the outputs was just not possible based on the available data. In these cases, the model was judged on its ability to represent the conceptualisation of the processes occurring in the catchments. While the lack of appropriate data means there will always be considerable uncertainty surrounding model validation, it can be argued that improved process understanding in an environment can be used to validate model outcomes to a degree, by assessing whether a model is getting the right results for the right reasons. Many water resource decisions are still made without adequate account being taken of the uncertainties inherent in assessing the response of hydrological systems. Certainly, with all the possible sources of uncertainty in a data scarce country such as South Africa, pure calibration based modelling is unlikely to produce reliable information for water resource managers as it can produce the right results for the wrong reasons. Thus it becomes essential to incorporate conceptual thinking into the modelling process, so that at the very least we are able to conclude that a model generates estimates that are consistent with, and reflect, our understanding (however limited) of the catchment processes. It is fairly clear that achieving the optimum model of a hydrological system may be fraught with difficulty, if not impossible. This makes it very difficult from a practitioner's point of view to decide which model and uncertainty estimation method to use. According to Beven (2009), this may be a transitional problem and in the future it may become clearer as we learn more about how to estimate the uncertainties associated with hydrological systems. Until then, a better understanding of the fundamental and most critical hydrogeological processes should be used to critically test and improve model predictions as far as possible. A major focus of the study was to identify whether the modified Pitman model could provide a practical tool for water resource managers by reliably determining the available water resource. The incorporation of surface and groundwater interaction routines seems to have resulted in a more robust and realistic model of basin hydrology. The overall conclusion is that the model, although simplified, is capable of representing the catchment scale processes that occur under most South African conditions.
- Full Text:
- Date Issued: 2014
- Authors: Tanner, Jane Louise
- Date: 2014
- Subjects: Groundwater -- South Africa , Water-supply -- Management , Integrated water development , Hydrogeology , Water resources development -- South Africa , Water -- Analysis , Groundwater -- Management , Watersheds -- South Africa , Hydrologic models
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:6043 , http://hdl.handle.net/10962/d1012994
- Description: The connections between surface water and groundwater systems remain poorly understood in many catchments throughout the world and yet they are fundamental to effectively managing water resources. Managing water resources in an integrated manner is not straightforward, particularly if both resources are being utilised, and especially in those regions that suffer problems of data scarcity. This study explores some of the principle issues associated with understanding and practically modelling surface and groundwater interactions. In South Africa, there remains much controversy over the most appropriate type of integrated model to be used and the way forward in terms of the development of the discipline; part of the disagreement stems from the fact that we cannot validate models adequately. This is largely due to traditional forms of model testing having limited power as it is difficult to differentiate between the uncertainties within different model structures, different sets of alternative parameter values and in the input data used to run the model. While model structural uncertainties are important to consider, the uncertainty from input data error together with parameter estimation error are often more significant to the overall residual error, and essential to consider if we want to achieve reliable predictions for water resource decisions. While new philosophies and theories on modelling and results validation have been developed (Beven, 2002; Gupta et al., 2008), in many cases models are not only still being validated and compared using sparse and uncertain datasets, but also expected to produce reliable predictions based on the flawed data. The approach in this study is focused on fundamental understanding of hydrological systems rather than calibration based modelling and promotes the use of all the available 'hard' and 'soft' data together with thoughtful conceptual examination of the processes occurring in an environment to ensure as far as possible that a model is generating sensible results by simulating the correct processes. The first part of the thesis focuses on characterising the 'typical' interaction environments found in South Africa. It was found that many traditional perceptual models are not necessarily applicable to South African conditions, largely due to the relative importance of unsaturated zone processes and the complexity of the dominantly fractured rock environments. The interaction environments were categorised into four main 'types' of environment. These include karst, primary, fractured rock (secondary), and alluvial environments. Processes critical to Integrated Water Resource Management (IWRM) were defined within each interaction type as a guideline to setting a model up to realistically represent the dominant processes in the respective settings. The second part of the thesis addressed the application and evaluation of the modified Pitman model (Hughes, 2004), which allows for surface and groundwater interaction behaviour at the catchment scale to be simulated. The issue is whether, given the different sources of uncertainty in the modelling process, we can differentiate one conceptual flow path from another in trying to refine the understanding and consequently have more faith in model predictions. Seven example catchments were selected from around South Africa to assess whether reliable integrated assessments can be carried out given the existing data. Specific catchment perceptual models were used to identify the critical processes occurring in each setting and the Pitman model was assessed on whether it could represent them (structural uncertainty). The available knowledge of specific environments or catchments was then examined in an attempt to resolve the parameter uncertainty present within each catchment and ensure the subsequent model setup was correctly representing the process understanding as far as possible. The confidence in the quantitative results inevitably varied with the amount and quality of the data available. While the model was deemed to be robust based on the behavioural results obtained in the majority of the case studies, in many cases a quantitative validation of the outputs was just not possible based on the available data. In these cases, the model was judged on its ability to represent the conceptualisation of the processes occurring in the catchments. While the lack of appropriate data means there will always be considerable uncertainty surrounding model validation, it can be argued that improved process understanding in an environment can be used to validate model outcomes to a degree, by assessing whether a model is getting the right results for the right reasons. Many water resource decisions are still made without adequate account being taken of the uncertainties inherent in assessing the response of hydrological systems. Certainly, with all the possible sources of uncertainty in a data scarce country such as South Africa, pure calibration based modelling is unlikely to produce reliable information for water resource managers as it can produce the right results for the wrong reasons. Thus it becomes essential to incorporate conceptual thinking into the modelling process, so that at the very least we are able to conclude that a model generates estimates that are consistent with, and reflect, our understanding (however limited) of the catchment processes. It is fairly clear that achieving the optimum model of a hydrological system may be fraught with difficulty, if not impossible. This makes it very difficult from a practitioner's point of view to decide which model and uncertainty estimation method to use. According to Beven (2009), this may be a transitional problem and in the future it may become clearer as we learn more about how to estimate the uncertainties associated with hydrological systems. Until then, a better understanding of the fundamental and most critical hydrogeological processes should be used to critically test and improve model predictions as far as possible. A major focus of the study was to identify whether the modified Pitman model could provide a practical tool for water resource managers by reliably determining the available water resource. The incorporation of surface and groundwater interaction routines seems to have resulted in a more robust and realistic model of basin hydrology. The overall conclusion is that the model, although simplified, is capable of representing the catchment scale processes that occur under most South African conditions.
- Full Text:
- Date Issued: 2014
“Watch-dogs for an Economy” : a determination of the origins of the South African Public Accountants' and Auditors' Board – as the Regulator of the Profession – principally through an analysis of the debates and related reports to the House of Assembly of the Parliament of the Union of South Africa in the period 1913–1940
- Lancaster, Jonathan Charles Swinburne
- Authors: Lancaster, Jonathan Charles Swinburne
- Date: 2014
- Subjects: Public Accountants' and Auditors' Board (South Africa) , Accounting -- Law and legislation -- South Africa , Accounting -- South Africa -- History , Accounting -- Standards -- South Africa , South Africa -- Economic conditions -- 1918-1961 , South Africa -- Politics and government -- 1909-1948
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:922 , http://hdl.handle.net/10962/d1020876
- Description: This thesis concentrates upon a new field of research in South African accounting scholarship – this being, in general terms, accounting history and more specifically an analysis of the origins of the Public Accountants’ and Auditors’ Board as watch-dog in relation to: ● the South African economy in the period 1913–1940; and ● the changing political framework (also in the period 1913–1940). The integration of economy, politics and personal ambition on the part of early 20th Century accounting societies, led to a variety of responses, counter proposals, stalemates and unfocused activity which caused the process of accountants’ registration to extend over 38 years in South Africa. This confusion was in strong contrast to the process of speedy registration of accountants in New Zealand and Australia. The final unification of South African accounting societies in 1951 created the Public Accountants’ and Auditors’ Board. Its creation, at long last, suggested an overarching control and regulation which was mirrored in the final political unification and economic stability of a South Africa dominated by Afrikaner Nationalists. One further element was interwoven into the fabric of the thesis – this being the application of institutional economic theory and its impact upon the accounting concepts of “material irregularity” and “reportable irregularity”.
- Full Text:
- Date Issued: 2014
- Authors: Lancaster, Jonathan Charles Swinburne
- Date: 2014
- Subjects: Public Accountants' and Auditors' Board (South Africa) , Accounting -- Law and legislation -- South Africa , Accounting -- South Africa -- History , Accounting -- Standards -- South Africa , South Africa -- Economic conditions -- 1918-1961 , South Africa -- Politics and government -- 1909-1948
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:922 , http://hdl.handle.net/10962/d1020876
- Description: This thesis concentrates upon a new field of research in South African accounting scholarship – this being, in general terms, accounting history and more specifically an analysis of the origins of the Public Accountants’ and Auditors’ Board as watch-dog in relation to: ● the South African economy in the period 1913–1940; and ● the changing political framework (also in the period 1913–1940). The integration of economy, politics and personal ambition on the part of early 20th Century accounting societies, led to a variety of responses, counter proposals, stalemates and unfocused activity which caused the process of accountants’ registration to extend over 38 years in South Africa. This confusion was in strong contrast to the process of speedy registration of accountants in New Zealand and Australia. The final unification of South African accounting societies in 1951 created the Public Accountants’ and Auditors’ Board. Its creation, at long last, suggested an overarching control and regulation which was mirrored in the final political unification and economic stability of a South Africa dominated by Afrikaner Nationalists. One further element was interwoven into the fabric of the thesis – this being the application of institutional economic theory and its impact upon the accounting concepts of “material irregularity” and “reportable irregularity”.
- Full Text:
- Date Issued: 2014
A formalised ontology for network attack classification
- Authors: Van Heerden, Renier Pelser
- Date: 2014
- Subjects: Computer networks -- Security measures Computer security Computer crimes -- Investigation Computer crimes -- Prevention
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4691 , http://hdl.handle.net/10962/d1011603
- Description: One of the most popular attack vectors against computers are their network connections. Attacks on computers through their networks are commonplace and have various levels of complexity. This research formally describes network-based computer attacks in the form of a story, formally and within an ontology. The ontology categorises network attacks where attack scenarios are the focal class. This class consists of: Denial-of- Service, Industrial Espionage, Web Defacement, Unauthorised Data Access, Financial Theft, Industrial Sabotage, Cyber-Warfare, Resource Theft, System Compromise, and Runaway Malware. This ontology was developed by building a taxonomy and a temporal network attack model. Network attack instances (also know as individuals) are classified according to their respective attack scenarios, with the use of an automated reasoner within the ontology. The automated reasoner deductions are verified formally; and via the automated reasoner, a relaxed set of scenarios is determined, which is relevant in a near real-time environment. A prototype system (called Aeneas) was developed to classify network-based attacks. Aeneas integrates the sensors into a detection system that can classify network attacks in a near real-time environment. To verify the ontology and the prototype Aeneas, a virtual test bed was developed in which network-based attacks were generated to verify the detection system. Aeneas was able to detect incoming attacks and classify them according to their scenario. The novel part of this research is the attack scenarios that are described in the form of a story, as well as formally and in an ontology. The ontology is used in a novel way to determine to which class attack instances belong and how the network attack ontology is affected in a near real-time environment.
- Full Text:
- Date Issued: 2014
- Authors: Van Heerden, Renier Pelser
- Date: 2014
- Subjects: Computer networks -- Security measures Computer security Computer crimes -- Investigation Computer crimes -- Prevention
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4691 , http://hdl.handle.net/10962/d1011603
- Description: One of the most popular attack vectors against computers are their network connections. Attacks on computers through their networks are commonplace and have various levels of complexity. This research formally describes network-based computer attacks in the form of a story, formally and within an ontology. The ontology categorises network attacks where attack scenarios are the focal class. This class consists of: Denial-of- Service, Industrial Espionage, Web Defacement, Unauthorised Data Access, Financial Theft, Industrial Sabotage, Cyber-Warfare, Resource Theft, System Compromise, and Runaway Malware. This ontology was developed by building a taxonomy and a temporal network attack model. Network attack instances (also know as individuals) are classified according to their respective attack scenarios, with the use of an automated reasoner within the ontology. The automated reasoner deductions are verified formally; and via the automated reasoner, a relaxed set of scenarios is determined, which is relevant in a near real-time environment. A prototype system (called Aeneas) was developed to classify network-based attacks. Aeneas integrates the sensors into a detection system that can classify network attacks in a near real-time environment. To verify the ontology and the prototype Aeneas, a virtual test bed was developed in which network-based attacks were generated to verify the detection system. Aeneas was able to detect incoming attacks and classify them according to their scenario. The novel part of this research is the attack scenarios that are described in the form of a story, as well as formally and in an ontology. The ontology is used in a novel way to determine to which class attack instances belong and how the network attack ontology is affected in a near real-time environment.
- Full Text:
- Date Issued: 2014
Electrospun fiber based colorimetric probes for aspartate aminotransferase and I7ß-estradiol
- Authors: Pule, Bellah Oreeditse
- Date: 2014
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54869 , vital:26623
- Description: Fabrication, characterization and application of electrospun polymer composite based colorimetric probes are presented in this thesis. The first part of the thesis involved the development of a protocol for in situ reduction of gold trication (Au³+) into metallic gold atoms with sodium borohydride. The prepared PS-Au NPs showed an SPR band at 542 nm. Furthermore the absorbance of the colloidal Au NPs in polystyrene exhibited a good linear correlation (r2 = 0.9934) to E2 concentration in the range 5 to 50 ppb. The lowest naked eye detection limit was found to be 0.5 ppb and could further be easily monitored by UV-vis spectrophotometer. Upon interaction with E2 Au NPs aggregated to give nanoparticle clusters, confirmed through TEM analysis. Different concentrations of Au NPs were found to have a significant effect on the conductivity of the PS-Au NPs solution. At low concentrations of Au NPs (0.002, 0.015 and 0.025% w/v) PS-Au NPs solution could be electrospun without clogging. The FE-SEM images showed a non-beaded morphology of PS-Au NPs composite fibers. Upon interaction of the colorimetric probe strips with various E2 concentrations it was observed that with increasing E2 concentrations (50 ng/ml to 1000 µg/ml) the colour of the probe changed gradually from white to shades of pink and eventually to shades of blue at higher E2 concentrations. The visible cut-off concentration was 100 ng/ml. The second component of the thesis focussed on the development of diazonium dye-nylon 6 colorimetric probe for aspartate aminotransferase. At optimal pH 7.4 the enzyme was stable, highly active and catalyzed a reaction that was susceptible to detailed kinetic analysis by continuous optical methods. The KM values for L-aspartate, a- ketoglutarate and oxaloacetate were 2.60, 0.59 and 0.066 mM, respectively. On the basis of these KM values the solid-state colorimetric probe was developed. A colour change occurred when an electrospun dye-N 6 probes were exposed to visibly detectable concentrations of oxaloacetate, an AST-catalyzed reaction product. While monitoring AST activity at 530 run, a linear relation was obtained between oxaloacetate concentrations ranging from 0.4 - 7.4 µg/ml. Naked eye detection limit of 2.4 µg/ml oxalaoacetate equivalence of 10 times the normal AST activity was attained. The colorimetric probe was in addition, tested against co-substrates aspartate, ketoglutarate and a variety of other compounds such as alanine, pryruvate, as well as glutamic, malaic and succinic acids known to interfere with AST activity. Each compound elicited a distinct and unambiguous colour change upon interaction with the colorimetric probe. Further X-ray powder diffraction (XRD), duNouy ring tensiometer, Brunauer- Emmett- Teller (BET) and energy dispersive X-ray spectroscopy (EDS/EDX) characterization confirmed composition and stability of the colorimetric probes. Colorimetric probes developed in this thesis are relatively cost effective, simple and "rugged" for measurement of analytes with visual detection without sample pretreatment in matrices, such as plasma and dairy effluents. The probes warrant further investigation as they have shown potential and offer a promising solid-state platform for both clinical diagnostics and environmental monitoring.
- Full Text:
- Date Issued: 2014
- Authors: Pule, Bellah Oreeditse
- Date: 2014
- Language: English
- Type: text , Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10962/54869 , vital:26623
- Description: Fabrication, characterization and application of electrospun polymer composite based colorimetric probes are presented in this thesis. The first part of the thesis involved the development of a protocol for in situ reduction of gold trication (Au³+) into metallic gold atoms with sodium borohydride. The prepared PS-Au NPs showed an SPR band at 542 nm. Furthermore the absorbance of the colloidal Au NPs in polystyrene exhibited a good linear correlation (r2 = 0.9934) to E2 concentration in the range 5 to 50 ppb. The lowest naked eye detection limit was found to be 0.5 ppb and could further be easily monitored by UV-vis spectrophotometer. Upon interaction with E2 Au NPs aggregated to give nanoparticle clusters, confirmed through TEM analysis. Different concentrations of Au NPs were found to have a significant effect on the conductivity of the PS-Au NPs solution. At low concentrations of Au NPs (0.002, 0.015 and 0.025% w/v) PS-Au NPs solution could be electrospun without clogging. The FE-SEM images showed a non-beaded morphology of PS-Au NPs composite fibers. Upon interaction of the colorimetric probe strips with various E2 concentrations it was observed that with increasing E2 concentrations (50 ng/ml to 1000 µg/ml) the colour of the probe changed gradually from white to shades of pink and eventually to shades of blue at higher E2 concentrations. The visible cut-off concentration was 100 ng/ml. The second component of the thesis focussed on the development of diazonium dye-nylon 6 colorimetric probe for aspartate aminotransferase. At optimal pH 7.4 the enzyme was stable, highly active and catalyzed a reaction that was susceptible to detailed kinetic analysis by continuous optical methods. The KM values for L-aspartate, a- ketoglutarate and oxaloacetate were 2.60, 0.59 and 0.066 mM, respectively. On the basis of these KM values the solid-state colorimetric probe was developed. A colour change occurred when an electrospun dye-N 6 probes were exposed to visibly detectable concentrations of oxaloacetate, an AST-catalyzed reaction product. While monitoring AST activity at 530 run, a linear relation was obtained between oxaloacetate concentrations ranging from 0.4 - 7.4 µg/ml. Naked eye detection limit of 2.4 µg/ml oxalaoacetate equivalence of 10 times the normal AST activity was attained. The colorimetric probe was in addition, tested against co-substrates aspartate, ketoglutarate and a variety of other compounds such as alanine, pryruvate, as well as glutamic, malaic and succinic acids known to interfere with AST activity. Each compound elicited a distinct and unambiguous colour change upon interaction with the colorimetric probe. Further X-ray powder diffraction (XRD), duNouy ring tensiometer, Brunauer- Emmett- Teller (BET) and energy dispersive X-ray spectroscopy (EDS/EDX) characterization confirmed composition and stability of the colorimetric probes. Colorimetric probes developed in this thesis are relatively cost effective, simple and "rugged" for measurement of analytes with visual detection without sample pretreatment in matrices, such as plasma and dairy effluents. The probes warrant further investigation as they have shown potential and offer a promising solid-state platform for both clinical diagnostics and environmental monitoring.
- Full Text:
- Date Issued: 2014
Vulnerability and adaptation of Zanzibar east coast communities to climate variability and change and other interacting stressors
- Authors: Makame, Makame Omar
- Date: 2014
- Subjects: Climatic changes -- Tanzania -- Zanzibar Bioclimatology Global temperature changes Food security -- Tanzania -- Zanzibar Water-supply -- Tanzania -- Zanzibar Sustainable development -- Tanzania -- Zanzibar Climatic changes -- Social aspects -- Tanzania -- Zanzibar Human ecology -- Tanzania -- Zanzibar Zanzibar -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4778 , http://hdl.handle.net/10962/d1011895
- Description: Climate variability and change as well as sea level rise poses significant challenges to livelihoods, water and food security in small island developing states (SIDSs) including the Zanzibar Islands. Thus, without planned strategic adaptation, the future projected changes in climate and sea level will intensify the vulnerability of these sensitive areas. This thesis is based on research conducted in two sites located in the north eastern parts of each island, namely Kiuyu Mbuyuni, Pemba Island and Matemwe, Unguja Island. The research focused firstly on assessing the vulnerability of these two coastal communities to climate variability and change and other stressors. This included investigation of (1) the perceptions of fishers, farmers and seaweed farmers regarding climate stressors and shocks and associated risks and impacts, (2) existing and possible future water and food security issues, and (3) household's access to important livelihood assets. This was followed by an exploration of the coping and adaptive responses of farmers, fishers and seaweed farmers to perceived shocks and stresses and some of the barriers to these responses. Lastly, an analysis of the implications of the findings for achieving sustainable coastal livelihoods and a resilient coastal community was undertaken. The general picture that emerges is that local people along the east coasts of both islands are already vulnerable to a wide range of stressors. Although variability in rainfall is not a new phenomenon in these areas, increasing frequency of dry spells and coastal floods resulting from the influence of El Niño and La Niña events exert enormous pressures on local activities (fishing, farming and seaweed farming) which are the crux of the local economy. The main argument of the study is that the nature and characteristics of these activities are the main source of sensitivity amongst these communities and this creates high levels of vulnerability to climate shocks and trends. This vulnerability is evidenced by the reoccurrence of localised food shortages and the observed food and water insecurity. The study found that food insecurity is a result of unreliable rainfall, drought and seasonality changes. These interacted with other contextual factors such as poor soil, low purchasing power and the lack of livelihood diversification options. In addition to exposure to these almost unavoidable risks from climate variability, the vulnerability of the local communities along the east coasts is also influenced by the low level of capital stocks and limited access to the assets that are important for coping and adaptation. Despite this, some households managed to overcome barriers and adapt in various ways both within the three main livelihood sectors (fishing, farming and seaweed farming) as well as through adopting options outside these sectors resulting in diversification of the livelihood portfolio. However, the study found that most of the strategies opted for by fishers, farmers and seaweed farmers were mainly spontaneous. Few planned adaptation measures supported by state authorities were observed across the sites, with the exception of the provision of motorised boats which were specifically meant to increase physical assets amongst fishers, reduce pressure in the marine conservation areas and prevent overfishing in-shore. Furthermore, numerous strategies that people adopted were discontinued when further barriers were encountered. Interestingly, some of the barriers that prevented households adapting were the same ones that forced households that had responded to abandon their adaptations. To increase resilience amongst east coast communities to current and future predicted changes in climate and sea level, the study argues that traditional livelihood activities (fishing, farming and seaweed farming) need to be better supported, and access to a range of livelihood assets improved. This may be achieved through increased access to local sources of water and facilitation of rainwater harvesting, expanding the livelihood options available to people and increasing climate change awareness, and access to sources of credit.
- Full Text:
- Date Issued: 2014
- Authors: Makame, Makame Omar
- Date: 2014
- Subjects: Climatic changes -- Tanzania -- Zanzibar Bioclimatology Global temperature changes Food security -- Tanzania -- Zanzibar Water-supply -- Tanzania -- Zanzibar Sustainable development -- Tanzania -- Zanzibar Climatic changes -- Social aspects -- Tanzania -- Zanzibar Human ecology -- Tanzania -- Zanzibar Zanzibar -- Economic conditions
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4778 , http://hdl.handle.net/10962/d1011895
- Description: Climate variability and change as well as sea level rise poses significant challenges to livelihoods, water and food security in small island developing states (SIDSs) including the Zanzibar Islands. Thus, without planned strategic adaptation, the future projected changes in climate and sea level will intensify the vulnerability of these sensitive areas. This thesis is based on research conducted in two sites located in the north eastern parts of each island, namely Kiuyu Mbuyuni, Pemba Island and Matemwe, Unguja Island. The research focused firstly on assessing the vulnerability of these two coastal communities to climate variability and change and other stressors. This included investigation of (1) the perceptions of fishers, farmers and seaweed farmers regarding climate stressors and shocks and associated risks and impacts, (2) existing and possible future water and food security issues, and (3) household's access to important livelihood assets. This was followed by an exploration of the coping and adaptive responses of farmers, fishers and seaweed farmers to perceived shocks and stresses and some of the barriers to these responses. Lastly, an analysis of the implications of the findings for achieving sustainable coastal livelihoods and a resilient coastal community was undertaken. The general picture that emerges is that local people along the east coasts of both islands are already vulnerable to a wide range of stressors. Although variability in rainfall is not a new phenomenon in these areas, increasing frequency of dry spells and coastal floods resulting from the influence of El Niño and La Niña events exert enormous pressures on local activities (fishing, farming and seaweed farming) which are the crux of the local economy. The main argument of the study is that the nature and characteristics of these activities are the main source of sensitivity amongst these communities and this creates high levels of vulnerability to climate shocks and trends. This vulnerability is evidenced by the reoccurrence of localised food shortages and the observed food and water insecurity. The study found that food insecurity is a result of unreliable rainfall, drought and seasonality changes. These interacted with other contextual factors such as poor soil, low purchasing power and the lack of livelihood diversification options. In addition to exposure to these almost unavoidable risks from climate variability, the vulnerability of the local communities along the east coasts is also influenced by the low level of capital stocks and limited access to the assets that are important for coping and adaptation. Despite this, some households managed to overcome barriers and adapt in various ways both within the three main livelihood sectors (fishing, farming and seaweed farming) as well as through adopting options outside these sectors resulting in diversification of the livelihood portfolio. However, the study found that most of the strategies opted for by fishers, farmers and seaweed farmers were mainly spontaneous. Few planned adaptation measures supported by state authorities were observed across the sites, with the exception of the provision of motorised boats which were specifically meant to increase physical assets amongst fishers, reduce pressure in the marine conservation areas and prevent overfishing in-shore. Furthermore, numerous strategies that people adopted were discontinued when further barriers were encountered. Interestingly, some of the barriers that prevented households adapting were the same ones that forced households that had responded to abandon their adaptations. To increase resilience amongst east coast communities to current and future predicted changes in climate and sea level, the study argues that traditional livelihood activities (fishing, farming and seaweed farming) need to be better supported, and access to a range of livelihood assets improved. This may be achieved through increased access to local sources of water and facilitation of rainwater harvesting, expanding the livelihood options available to people and increasing climate change awareness, and access to sources of credit.
- Full Text:
- Date Issued: 2014
Combating corruption while respecting human rights : a critical study of the non-conviction based assets recovery mechanism in Kenya and South Africa
- Authors: Obura, Ken Otieno
- Date: 2014
- Subjects: Human rights -- Kenya , Human rights -- South Africa , Corruption -- Kenya , Corruption -- South Africa , Reparation (Criminal justice) -- Kenya , Reparation (Criminal justice) -- South Africa , Political corruption -- Kenya , Political corruption -- South Africa , Corruption investigation -- Kenya , Corruption investigation -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3719 , http://hdl.handle.net/10962/d1013159
- Description: The thesis contributes to the search for sound anti-corruption laws and practices that are effective and fair. It argues for the respect for human rights in the crafting and implementation of anti-corruption laws as a requisite for successful control of corruption. The basis for this argument is threefold: First, human rights provide a framework for checking against abuse of state’s police power, an abuse which if allowed to take root, would make the fight against corruption lose its legitimacy in the eye of the people. Second, human rights ensure that the interest of individuals is catered for in the crafting of anti-corruption laws and practices thereby denying perpetrators of corruption legal excuses that can be exploited to delay or frustrate corruption cases in the courts of law. Third, human rights provide a useful framework for balancing competing interests in the area of corruption control – it enables society to craft measures that fulfils the public interest in the eradication of corruption while concomitantly assuring the competing public interest in the protection of individual members’ liberties – a condition that is necessary if the support of the holders of these competing interests is to be enlisted and fostered in the fight against corruption. The thesis focuses on the study of the non-conviction based assets recovery mechanism, a mechanism that allows the state to apply a procedure lacking in criminal law safeguards to address criminal behaviour. The mechanism is thus beset with avenues for abuse, which if unchecked could have debilitating effects not only to individual liberties but also to the long term legitimacy of the fight against corruption. In this regard, the thesis examines how the human rights framework has been used in Kenya and South Africa to check on the potential dangers of the non-conviction based mechanism and to provide for a proportional balance between the imperative of corruption control and the guarantee against arbitrary deprivation of property. The aim is to unravel the benefits of respecting human rights in the fight against corruption in general and in the non-conviction based assets recovery in particular. Kenya and South Africa are chosen for study because they provide two models of non-conviction based mechanisms with different levels of safeguards, for comparative consideration.
- Full Text:
- Date Issued: 2014
- Authors: Obura, Ken Otieno
- Date: 2014
- Subjects: Human rights -- Kenya , Human rights -- South Africa , Corruption -- Kenya , Corruption -- South Africa , Reparation (Criminal justice) -- Kenya , Reparation (Criminal justice) -- South Africa , Political corruption -- Kenya , Political corruption -- South Africa , Corruption investigation -- Kenya , Corruption investigation -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3719 , http://hdl.handle.net/10962/d1013159
- Description: The thesis contributes to the search for sound anti-corruption laws and practices that are effective and fair. It argues for the respect for human rights in the crafting and implementation of anti-corruption laws as a requisite for successful control of corruption. The basis for this argument is threefold: First, human rights provide a framework for checking against abuse of state’s police power, an abuse which if allowed to take root, would make the fight against corruption lose its legitimacy in the eye of the people. Second, human rights ensure that the interest of individuals is catered for in the crafting of anti-corruption laws and practices thereby denying perpetrators of corruption legal excuses that can be exploited to delay or frustrate corruption cases in the courts of law. Third, human rights provide a useful framework for balancing competing interests in the area of corruption control – it enables society to craft measures that fulfils the public interest in the eradication of corruption while concomitantly assuring the competing public interest in the protection of individual members’ liberties – a condition that is necessary if the support of the holders of these competing interests is to be enlisted and fostered in the fight against corruption. The thesis focuses on the study of the non-conviction based assets recovery mechanism, a mechanism that allows the state to apply a procedure lacking in criminal law safeguards to address criminal behaviour. The mechanism is thus beset with avenues for abuse, which if unchecked could have debilitating effects not only to individual liberties but also to the long term legitimacy of the fight against corruption. In this regard, the thesis examines how the human rights framework has been used in Kenya and South Africa to check on the potential dangers of the non-conviction based mechanism and to provide for a proportional balance between the imperative of corruption control and the guarantee against arbitrary deprivation of property. The aim is to unravel the benefits of respecting human rights in the fight against corruption in general and in the non-conviction based assets recovery in particular. Kenya and South Africa are chosen for study because they provide two models of non-conviction based mechanisms with different levels of safeguards, for comparative consideration.
- Full Text:
- Date Issued: 2014