Green zone nation : the securitisation and militarisation of the 2010 FIFA World Cup, South Africa
- McMichael, Christopher Bryden
- Authors: McMichael, Christopher Bryden
- Date: 2013 , 2013-04-22
- Subjects: World Cup (Soccer) (2010 : South Africa) -- Safety measures -- Research Fédération internationale de football association Militarism -- Research -- South Africa Sports -- Political aspects -- Research -- South Africa Police -- South Africa South Africa -- Armed Forces Crime -- South Africa Violent crimes -- South Africa Violent crimes -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2752 , http://hdl.handle.net/10962/d1001622
- Description: This thesis explores the relationship between the safety and security measures for the 2010 FIFA World Cup and the militarisation of urban space and policing in post-apartheid South Africa. In particular, it focuses upon how the South African state and FIFA, the owners of the World Cup franchise, worked to present the World Cup as an event which required exceptional levels of security – resulting in a historically unprecedented joint police and military operation across host cities. However, in contrast with previous research on these security measures, this thesis aims to interrogate the political and commercial forces which constructed security and positions them against a backdrop of intensified state violence and social exclusion in South Africa. Concurrently, the South African case was indicative of an international militarisation of major events, with policing operations comparable to national states of emergency. This is representative of the ‘new military urbanism’ in which everyday urban life is rendered as a site of ubiquitous risk, leading to the increased diffusion of military tactics and doctrines in policing and policy. While the interpenetration between urbanism and militarism has often been studied against the context of the ‘war on terror’, in the case of South Africa this has primarily been accelerated by a pervasive social fear of violent crime, which has resulted in the securitisation of cities, the remilitarisation of policing and the intensification of a historical legacy of socio-spatial inequalities. The South African government aimed to use the World Cup to ‘rebrand’ the country’s violent international image, while promising that security measures would leave a legacy of safer cities for ordinary South Africans. The concept of legacies was also responsive to the commercial imperatives of FIFA and a range of other security actors, including foreign governments and the private security industry. However these policing measures were primarily cosmetic and designed to allay the fears of foreign tourists and the national middle class. In practice security measures pivoted around the enforcement of social control and urban marginalisation while serving as a training ground for an increasingly repressive state security apparatus. Security was as much a matter of fortifying islands of privilege and aiding a project of financial extraction as protecting the public from harm. , Microsoft� Office Word 2007 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
- Authors: McMichael, Christopher Bryden
- Date: 2013 , 2013-04-22
- Subjects: World Cup (Soccer) (2010 : South Africa) -- Safety measures -- Research Fédération internationale de football association Militarism -- Research -- South Africa Sports -- Political aspects -- Research -- South Africa Police -- South Africa South Africa -- Armed Forces Crime -- South Africa Violent crimes -- South Africa Violent crimes -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2752 , http://hdl.handle.net/10962/d1001622
- Description: This thesis explores the relationship between the safety and security measures for the 2010 FIFA World Cup and the militarisation of urban space and policing in post-apartheid South Africa. In particular, it focuses upon how the South African state and FIFA, the owners of the World Cup franchise, worked to present the World Cup as an event which required exceptional levels of security – resulting in a historically unprecedented joint police and military operation across host cities. However, in contrast with previous research on these security measures, this thesis aims to interrogate the political and commercial forces which constructed security and positions them against a backdrop of intensified state violence and social exclusion in South Africa. Concurrently, the South African case was indicative of an international militarisation of major events, with policing operations comparable to national states of emergency. This is representative of the ‘new military urbanism’ in which everyday urban life is rendered as a site of ubiquitous risk, leading to the increased diffusion of military tactics and doctrines in policing and policy. While the interpenetration between urbanism and militarism has often been studied against the context of the ‘war on terror’, in the case of South Africa this has primarily been accelerated by a pervasive social fear of violent crime, which has resulted in the securitisation of cities, the remilitarisation of policing and the intensification of a historical legacy of socio-spatial inequalities. The South African government aimed to use the World Cup to ‘rebrand’ the country’s violent international image, while promising that security measures would leave a legacy of safer cities for ordinary South Africans. The concept of legacies was also responsive to the commercial imperatives of FIFA and a range of other security actors, including foreign governments and the private security industry. However these policing measures were primarily cosmetic and designed to allay the fears of foreign tourists and the national middle class. In practice security measures pivoted around the enforcement of social control and urban marginalisation while serving as a training ground for an increasingly repressive state security apparatus. Security was as much a matter of fortifying islands of privilege and aiding a project of financial extraction as protecting the public from harm. , Microsoft� Office Word 2007 , Adobe Acrobat 9.53 Paper Capture Plug-in
- Full Text:
Growth and gonad size in cultured South African abalone, Haliotis midae
- Authors: Riddin, Nicholas Alwyn
- Date: 2013
- Subjects: Haliotis midae -- South Africa , Haliotis midae fisheries -- South Africa , Abalone culture -- South Africa , Abalones -- Physiology -- South Africa , Abalones -- Growth -- South Africa , Abalones -- Feeding and feeds -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5180 , http://hdl.handle.net/10962/d1001651 , Haliotis midae -- South Africa , Haliotis midae fisheries -- South Africa , Abalone culture -- South Africa , Abalones -- Physiology -- South Africa , Abalones -- Growth -- South Africa , Abalones -- Feeding and feeds -- South Africa
- Description: According to farm records, cultured Haliotis midae (50-70 g.abalone⁻¹) were growing 10% slower in winter when compared to summer. This reduction in growth rate also coincided with enlarged gonads. Initial trials showed that there were differences in mean monthly growth rates ranging from 1.97 – 5.14 g abalone⁻¹ month⁻¹, and gonad bulk index (GBI) also varied between months (GBI range: 26.88 ± 12.87 to 51.03 ± 34.47). The investment of energy into gonad tissue growth did not compromise whole body growth as the abalone continued to gain weight throughout the reproductive periods, probably due to gonadal growth. Growth of this size class of abalone was not influenced by water temperature or day length, suggesting favourable on-farm culture conditions (regression analyses, p > 0.05). There is no need to implement a seasonal dietary regime. Cultured H. midae were fed artificial diets with different protein sources, including only soya, only fishmeal, a combination of soya and fishmeal, and these were compared to kelp-fed abalone. Kelp-fed abalone grew slower than those fed artificial feeds (p>0.05). Gonad growth was the greatest when soya meal was included in the diet (average GBI: 74.91 ± 23.31), while the average gonad size of abalone fed the fishmealbased diet had gonads which were 38% smaller, and kelp-fed abalone had gonads which were 75% smaller than those of the abalone fed on diets containing soya meal. The increased gonad mass in abalone fed on diets including soya meal could be attributed to phytoestrogenic activity, as a result of the presence of isoflavones found in the soya plant; this remains to be tested. The use of soya in brood stock diet development is advised. The influence of dietary protein to energy ratio (1.41 – 2.46 g MJ⁻¹) on growth and gonad size was tested. Protein and energy levels within the ranges tested (22 and 33% protein; 13.5 and 15.6 MJ kg⁻¹) did not interact to influence growth rates of cultured H. midae. GBI increased from 50.67 ± 4.16 to 83.93 ± 9.35 units as a function of dietary protein to energy ratio (y = 42.02 x⁰·⁸¹; r² = 0.19; regression analysis: F₁¸₃₈ = 8.9; p = 0.005). In addition, protein level influenced gonad size, with gonad growth being greater in abalone fed the high protein diet (factorial ANOVA: F₁¸₃₂ = 7.1, p = 0.012). Canning yields were reduced by 7% when the protein content was increased, while increasing the quantity of dietary energy improved canning yields by ~ 6% (one-way ANOVA: F₁¸₂₈ = 14.4, p= 0.001). The present study provided evidence that although growth rates are varying seasonally, reproductive investment is not hindering weight gain. Gonad growth can be influenced if desired by farms, depending on the level of soya inclusion, as well as the protein to energy ratio in the diet. Monthly variation in growth and gonad size, as well as the influence of diet on gonad growth were highlighted, and the implications for farm application and further research were discussed.
- Full Text:
- Authors: Riddin, Nicholas Alwyn
- Date: 2013
- Subjects: Haliotis midae -- South Africa , Haliotis midae fisheries -- South Africa , Abalone culture -- South Africa , Abalones -- Physiology -- South Africa , Abalones -- Growth -- South Africa , Abalones -- Feeding and feeds -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5180 , http://hdl.handle.net/10962/d1001651 , Haliotis midae -- South Africa , Haliotis midae fisheries -- South Africa , Abalone culture -- South Africa , Abalones -- Physiology -- South Africa , Abalones -- Growth -- South Africa , Abalones -- Feeding and feeds -- South Africa
- Description: According to farm records, cultured Haliotis midae (50-70 g.abalone⁻¹) were growing 10% slower in winter when compared to summer. This reduction in growth rate also coincided with enlarged gonads. Initial trials showed that there were differences in mean monthly growth rates ranging from 1.97 – 5.14 g abalone⁻¹ month⁻¹, and gonad bulk index (GBI) also varied between months (GBI range: 26.88 ± 12.87 to 51.03 ± 34.47). The investment of energy into gonad tissue growth did not compromise whole body growth as the abalone continued to gain weight throughout the reproductive periods, probably due to gonadal growth. Growth of this size class of abalone was not influenced by water temperature or day length, suggesting favourable on-farm culture conditions (regression analyses, p > 0.05). There is no need to implement a seasonal dietary regime. Cultured H. midae were fed artificial diets with different protein sources, including only soya, only fishmeal, a combination of soya and fishmeal, and these were compared to kelp-fed abalone. Kelp-fed abalone grew slower than those fed artificial feeds (p>0.05). Gonad growth was the greatest when soya meal was included in the diet (average GBI: 74.91 ± 23.31), while the average gonad size of abalone fed the fishmealbased diet had gonads which were 38% smaller, and kelp-fed abalone had gonads which were 75% smaller than those of the abalone fed on diets containing soya meal. The increased gonad mass in abalone fed on diets including soya meal could be attributed to phytoestrogenic activity, as a result of the presence of isoflavones found in the soya plant; this remains to be tested. The use of soya in brood stock diet development is advised. The influence of dietary protein to energy ratio (1.41 – 2.46 g MJ⁻¹) on growth and gonad size was tested. Protein and energy levels within the ranges tested (22 and 33% protein; 13.5 and 15.6 MJ kg⁻¹) did not interact to influence growth rates of cultured H. midae. GBI increased from 50.67 ± 4.16 to 83.93 ± 9.35 units as a function of dietary protein to energy ratio (y = 42.02 x⁰·⁸¹; r² = 0.19; regression analysis: F₁¸₃₈ = 8.9; p = 0.005). In addition, protein level influenced gonad size, with gonad growth being greater in abalone fed the high protein diet (factorial ANOVA: F₁¸₃₂ = 7.1, p = 0.012). Canning yields were reduced by 7% when the protein content was increased, while increasing the quantity of dietary energy improved canning yields by ~ 6% (one-way ANOVA: F₁¸₂₈ = 14.4, p= 0.001). The present study provided evidence that although growth rates are varying seasonally, reproductive investment is not hindering weight gain. Gonad growth can be influenced if desired by farms, depending on the level of soya inclusion, as well as the protein to energy ratio in the diet. Monthly variation in growth and gonad size, as well as the influence of diet on gonad growth were highlighted, and the implications for farm application and further research were discussed.
- Full Text:
Halogenated oxindole and indoles from the South African marine ascidian Distaplia skoogi:
- Bromley, Candice L, Parker-Nance, Shirley, de la Mare, Jo-Anne, Edkins, Adrienne L, Beukes, Denzil R, Davies-Coleman, Michael T
- Authors: Bromley, Candice L , Parker-Nance, Shirley , de la Mare, Jo-Anne , Edkins, Adrienne L , Beukes, Denzil R , Davies-Coleman, Michael T
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164918 , vital:41184
- Description: The known 3,6-dibromoindole (1), 6-bromo-3-chloroindole (2) and 6-bromo-2-oxindole (3) were isolated from the marine ascidian (sea squirt) Distapia skoogi collected from Algoa Bay, South Africa. Standard spectroscopic techniques were used to elucidate the structures of 1-3. All three compounds were found to be moderately cytotoxic to metastatic MDA-MB-231 breast cancer cells.
- Full Text:
- Authors: Bromley, Candice L , Parker-Nance, Shirley , de la Mare, Jo-Anne , Edkins, Adrienne L , Beukes, Denzil R , Davies-Coleman, Michael T
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164918 , vital:41184
- Description: The known 3,6-dibromoindole (1), 6-bromo-3-chloroindole (2) and 6-bromo-2-oxindole (3) were isolated from the marine ascidian (sea squirt) Distapia skoogi collected from Algoa Bay, South Africa. Standard spectroscopic techniques were used to elucidate the structures of 1-3. All three compounds were found to be moderately cytotoxic to metastatic MDA-MB-231 breast cancer cells.
- Full Text:
Halting degradation of Southern Cape peatlands in agricultural landscapes
- Job, Nancy, Ellery, William F N
- Authors: Job, Nancy , Ellery, William F N
- Date: 2013
- Subjects: Peatlands -- South Africa -- Southern Cape Wetland ecology -- South Africa -- Southern Cape South Africa -- Social conditions
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/50013 , vital:25951
- Description: Palmiet peatlands in the agricultural landscape are viewed by farmers as problematic. They obstruct the effective passage of water along watercourses and therefore promote localized flooding of lands and infrastructure, and they trap sediment delivered along watercourses that drowns fields and infrastructure with sedimentary deposits. These events are problematic for farmers trying to make a living off the land. Wetlands are also often viewed as wastelands that should be put to more productive use. The obvious thing to do is to bring in machinery to drain the wetlands and improve the flow of water and sediment through these wetlands.
- Full Text:
- Authors: Job, Nancy , Ellery, William F N
- Date: 2013
- Subjects: Peatlands -- South Africa -- Southern Cape Wetland ecology -- South Africa -- Southern Cape South Africa -- Social conditions
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/50013 , vital:25951
- Description: Palmiet peatlands in the agricultural landscape are viewed by farmers as problematic. They obstruct the effective passage of water along watercourses and therefore promote localized flooding of lands and infrastructure, and they trap sediment delivered along watercourses that drowns fields and infrastructure with sedimentary deposits. These events are problematic for farmers trying to make a living off the land. Wetlands are also often viewed as wastelands that should be put to more productive use. The obvious thing to do is to bring in machinery to drain the wetlands and improve the flow of water and sediment through these wetlands.
- Full Text:
High-throughput modelling and structural investigation of cysteine protease complexes with protein inhibitors
- Authors: Kroon, Matthys Christoffel
- Date: 2013
- Subjects: Cysteine proteinases Cysteine proteinases -- Inhibitors Papain Cystatins Malaria -- Chemotherapy Homology (Biology) Protein-protein interactions
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3885 , http://hdl.handle.net/10962/d1001619
- Description: The papain-like cysteine protease family (C1 proteases) is highly important because of its involvement in research and industrial applications and its role in various human diseases. Protein inhibitors are an important aspect of C1 protease biology and are relevant to its clinical, industrial and research importance. To study the interaction between the proteases and the inhibitors it is very useful to have accurate structural models of the protease-inhibitor complexes. To this end, a high-throughput pipeline for modelling complexes of papain-like cysteine proteases and protein inhibitors was implemented and tested (Tastan Bishop & Kroon, 2011). The pipeline utilizes a novel technique for obtaining modelling templates by using superpositioning to combine coordinates from separate experimental structures. To test the pipeline, models of complexes with known structures (test set) were modelled using many different templates and the resultant models evaluated to compare the quality of the different templates. It was found that use of the new technique to obtain templates did not introduce significant errors, while allowing closer homologs to be used for modelling - leading to more accurate models. The test set models were also used to evaluate certain steps of the modelling protocol. The effect of Rosetta energy minimization on model accuracy and the use of Rosetta energy and DOPE Z-score values to identify accurate models were investigated. Several complexes were then modelled using the best available templates according to criteria informed by the previous results. A website was built that allows a user to download any of the metrics or models produced in the study. This website is accessible at http://rubi.ru.ac.za/cpmdb
- Full Text:
- Authors: Kroon, Matthys Christoffel
- Date: 2013
- Subjects: Cysteine proteinases Cysteine proteinases -- Inhibitors Papain Cystatins Malaria -- Chemotherapy Homology (Biology) Protein-protein interactions
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3885 , http://hdl.handle.net/10962/d1001619
- Description: The papain-like cysteine protease family (C1 proteases) is highly important because of its involvement in research and industrial applications and its role in various human diseases. Protein inhibitors are an important aspect of C1 protease biology and are relevant to its clinical, industrial and research importance. To study the interaction between the proteases and the inhibitors it is very useful to have accurate structural models of the protease-inhibitor complexes. To this end, a high-throughput pipeline for modelling complexes of papain-like cysteine proteases and protein inhibitors was implemented and tested (Tastan Bishop & Kroon, 2011). The pipeline utilizes a novel technique for obtaining modelling templates by using superpositioning to combine coordinates from separate experimental structures. To test the pipeline, models of complexes with known structures (test set) were modelled using many different templates and the resultant models evaluated to compare the quality of the different templates. It was found that use of the new technique to obtain templates did not introduce significant errors, while allowing closer homologs to be used for modelling - leading to more accurate models. The test set models were also used to evaluate certain steps of the modelling protocol. The effect of Rosetta energy minimization on model accuracy and the use of Rosetta energy and DOPE Z-score values to identify accurate models were investigated. Several complexes were then modelled using the best available templates according to criteria informed by the previous results. A website was built that allows a user to download any of the metrics or models produced in the study. This website is accessible at http://rubi.ru.ac.za/cpmdb
- Full Text:
How community participation and stakeholder involvement can improve recycling : an investigation of initiatives and opportunities in Simunye
- Authors: Myeni, Jabu R
- Date: 2013
- Subjects: Recycling (Waste, etc.) -- Swaziland Refuse and refuse disposal -- Swaziland -- Citizen participation
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:803 , http://hdl.handle.net/10962/d1006457
- Description: This report presents the findings of a research project whereby the initiatives and opportunities for municipal solid waste (MSW) recycling were investigated in the town of Simunye, in Swaziland with a view to establish how recycling, in particular household waste recycling, can be improved through stakeholder involvement and community participation during the planning and implementation of a sustainable system for household waste recycling in Simunye. The reason for focusing on household waste was because source separation of household waste was identified as a potential area for improving efficiencies and cutting costs by the local authority. It was deemed necessary to conduct research because there was a history of failure in respect of household recycling. In 2006 an initiative, by the local authority, for separating household waste at source had ended up in failure. The participation rates of the households turned out to be very low even though they had been issued, free of charge, some plastic bags for sorting the waste. Some of the households were found using the bags for other purposes rather than recycling. As a result, the initiative had to be suspended (White, 2010). There is a new move to revive the project in order to cut costs and minimize wastages. This time around the local authority is determined for the new project to be a success story. Since the underlying causes for the failure of the previous initiative were never investigated formally (Khumalo, 2010), the starting point would be to identify and try to eliminate all the potential barriers to recycling through a consultative process to start with.
- Full Text:
- Authors: Myeni, Jabu R
- Date: 2013
- Subjects: Recycling (Waste, etc.) -- Swaziland Refuse and refuse disposal -- Swaziland -- Citizen participation
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:803 , http://hdl.handle.net/10962/d1006457
- Description: This report presents the findings of a research project whereby the initiatives and opportunities for municipal solid waste (MSW) recycling were investigated in the town of Simunye, in Swaziland with a view to establish how recycling, in particular household waste recycling, can be improved through stakeholder involvement and community participation during the planning and implementation of a sustainable system for household waste recycling in Simunye. The reason for focusing on household waste was because source separation of household waste was identified as a potential area for improving efficiencies and cutting costs by the local authority. It was deemed necessary to conduct research because there was a history of failure in respect of household recycling. In 2006 an initiative, by the local authority, for separating household waste at source had ended up in failure. The participation rates of the households turned out to be very low even though they had been issued, free of charge, some plastic bags for sorting the waste. Some of the households were found using the bags for other purposes rather than recycling. As a result, the initiative had to be suspended (White, 2010). There is a new move to revive the project in order to cut costs and minimize wastages. This time around the local authority is determined for the new project to be a success story. Since the underlying causes for the failure of the previous initiative were never investigated formally (Khumalo, 2010), the starting point would be to identify and try to eliminate all the potential barriers to recycling through a consultative process to start with.
- Full Text:
How do teachers characterise their teaching for conceptual understanding and procedural fluency?: a case study of two teachers
- Junius, Daniel Franscius, Danie Junius
- Authors: Junius, Daniel Franscius , Danie Junius
- Date: 2013
- Subjects: Mathematics -- Study and teaching (Secondary) -- Namibia Mathematics -- Study and teaching -- Case studies
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: vital:1360 , http://hdl.handle.net/10962/d1001426
- Description: Over many years the practice or art of teaching Mathematics posed itself as, not only being different from the practice of teaching any other subject, but to have many challenges and opportunities that ask for exploration and understanding. Just after independence in 1990, Namibia has embarked upon a reform process for the entire education system. Many changes were brought about to create a uniform, equal system for all. However, many challenges still remain to be addressed. Mathematics education remains one of the key areas where Namibian teachers can contribute towards the improvement of the subject. Unsatisfactory results, under-qualified teachers, and a negative disposition towards Mathematics are some of the challenges. These challenges are not unique to Namibia. Across the globe psychologists, philosophers and educators continue to engage in debates and research projects in search of answers and solutions for the improvement of Mathematics education. Despite encountering numerous obstacles, many teachers are dedicated and achieve outstanding results with their learners. This thesis reports on a research project that focused on the Mathematics teaching practice of two teachers whose experiences can make a positive contribution to the improvement of Mathematics teaching in Namibia. Furthermore, this case study investigated and attempted to understand the Mathematics teaching practices of two proficient teachers who each claimed to have a specific and unique approach to teaching Mathematics. The one claimed to be mainly procedural in her Mathematics teaching, while the other one claimed to teach mainly in a conceptual manner. Both achieve very good results with their classes and attribute their own teaching orientations to a process of several experiences they went through as students and in their careers. The study revealed that both claims are substantiated and that each teacher was consistent in her claimed approach. Many challenges and constraints were encountered by both teachers, but in their unique and specific ways each teacher’s chosen teaching approach supported them to overcome these. It was evident from the findings that each teacher’s practice came about as an evolutionary process over an extended period of time. As many challenges and limitations are universal, it is believed that in sharing experiences, teachers can benefit from each other by improving their practice. It was clearly stated by both participants that the re-thinking of and reflecting on their own practices provided them with new insights and motivation. Peer support and sharing of practices contribute positively towards the improvement of the teachers’ classroom practices.
- Full Text:
- Authors: Junius, Daniel Franscius , Danie Junius
- Date: 2013
- Subjects: Mathematics -- Study and teaching (Secondary) -- Namibia Mathematics -- Study and teaching -- Case studies
- Language: English
- Type: text , Thesis , Masters , MEd
- Identifier: vital:1360 , http://hdl.handle.net/10962/d1001426
- Description: Over many years the practice or art of teaching Mathematics posed itself as, not only being different from the practice of teaching any other subject, but to have many challenges and opportunities that ask for exploration and understanding. Just after independence in 1990, Namibia has embarked upon a reform process for the entire education system. Many changes were brought about to create a uniform, equal system for all. However, many challenges still remain to be addressed. Mathematics education remains one of the key areas where Namibian teachers can contribute towards the improvement of the subject. Unsatisfactory results, under-qualified teachers, and a negative disposition towards Mathematics are some of the challenges. These challenges are not unique to Namibia. Across the globe psychologists, philosophers and educators continue to engage in debates and research projects in search of answers and solutions for the improvement of Mathematics education. Despite encountering numerous obstacles, many teachers are dedicated and achieve outstanding results with their learners. This thesis reports on a research project that focused on the Mathematics teaching practice of two teachers whose experiences can make a positive contribution to the improvement of Mathematics teaching in Namibia. Furthermore, this case study investigated and attempted to understand the Mathematics teaching practices of two proficient teachers who each claimed to have a specific and unique approach to teaching Mathematics. The one claimed to be mainly procedural in her Mathematics teaching, while the other one claimed to teach mainly in a conceptual manner. Both achieve very good results with their classes and attribute their own teaching orientations to a process of several experiences they went through as students and in their careers. The study revealed that both claims are substantiated and that each teacher was consistent in her claimed approach. Many challenges and constraints were encountered by both teachers, but in their unique and specific ways each teacher’s chosen teaching approach supported them to overcome these. It was evident from the findings that each teacher’s practice came about as an evolutionary process over an extended period of time. As many challenges and limitations are universal, it is believed that in sharing experiences, teachers can benefit from each other by improving their practice. It was clearly stated by both participants that the re-thinking of and reflecting on their own practices provided them with new insights and motivation. Peer support and sharing of practices contribute positively towards the improvement of the teachers’ classroom practices.
- Full Text:
How does subjective well-being evolve with age? A literature review
- López Ulloa, Beatriz Fabiola, Moller, Valerie, Sousa-Poza, Alfonso
- Authors: López Ulloa, Beatriz Fabiola , Moller, Valerie , Sousa-Poza, Alfonso
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67185 , vital:29056 , https://doi.org/10.1007/s12062-013-9085-0
- Description: publisher version , This literature review provides an overview of the theoretical and empirical research in several disciplines on the relation between ageing and subjective well-being, i.e., how subjective well-being evolves across the lifespan. Because of the different methodologies, data sets and samples used, comparison among disciplines and studies is difficult. However, extant studies do show either a U-shaped, inverted U-shaped or linear relation between ageing and subjective well-being.
- Full Text: false
- Authors: López Ulloa, Beatriz Fabiola , Moller, Valerie , Sousa-Poza, Alfonso
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67185 , vital:29056 , https://doi.org/10.1007/s12062-013-9085-0
- Description: publisher version , This literature review provides an overview of the theoretical and empirical research in several disciplines on the relation between ageing and subjective well-being, i.e., how subjective well-being evolves across the lifespan. Because of the different methodologies, data sets and samples used, comparison among disciplines and studies is difficult. However, extant studies do show either a U-shaped, inverted U-shaped or linear relation between ageing and subjective well-being.
- Full Text: false
How much its own and to what end?: SADC and the culture of security and regional organisation in Southern Africa
- Authors: Bischoff, Paul, 1954-
- Date: 2013
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/161650 , vital:40650 , ISBN 9781134118656
- Description: This book aims to examine the conceptions and practices of security adopted by Regional Organisations (ROs) across the globe. Since the end of the Cold War, there has been an increased focus on regions as a relevant realm for security, with actors within regional contexts identifying a significant degree of interdependency between one another. As a consequence, international security has taken on a distinct regionally institutionalised character, as seen by the increase in calls for greater utilisation of ‘Chapter VIII: Regional Arrangements’ of the UN, in order to create a devolved UN-led system of global security management. However, the idea of a system of global security management is a remote prospect, because divergence seems to be as important as commonality in terms of regional security.
- Full Text:
- Authors: Bischoff, Paul, 1954-
- Date: 2013
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/161650 , vital:40650 , ISBN 9781134118656
- Description: This book aims to examine the conceptions and practices of security adopted by Regional Organisations (ROs) across the globe. Since the end of the Cold War, there has been an increased focus on regions as a relevant realm for security, with actors within regional contexts identifying a significant degree of interdependency between one another. As a consequence, international security has taken on a distinct regionally institutionalised character, as seen by the increase in calls for greater utilisation of ‘Chapter VIII: Regional Arrangements’ of the UN, in order to create a devolved UN-led system of global security management. However, the idea of a system of global security management is a remote prospect, because divergence seems to be as important as commonality in terms of regional security.
- Full Text:
Human Rights and Conflict Transformation in Africa
- Authors: Juma, Laurence
- Date: 2013
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/127449 , vital:36012 , ISBN 9789956790418 , http://www.africanbookscollective.com/books/human-rights-and-conflict-transformation-in-africa
- Description: This study maps the interactions between human rights norms and values, on the one hand, and conflict resolution, post–conflict peace-building and reconstruction, on the other. It advances the view both from a theoretical and practical standpoint, that human rights have a role to play throughout the life of any conflict: from the pre-conflict to the post-conflict and reconstruction stages. Identifying entry points for human rights in the pre-conflict stage leading up to the establishment of the rule of law and societal reconstruction after the conflict, this book uses Sierra Leone and Democratic Republic of Congo experiences to illustrate the obstacles, the successes, and the significance of human rights norms to the overall peace agenda in societies afflicted by conflict.
- Full Text: false
- Authors: Juma, Laurence
- Date: 2013
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/127449 , vital:36012 , ISBN 9789956790418 , http://www.africanbookscollective.com/books/human-rights-and-conflict-transformation-in-africa
- Description: This study maps the interactions between human rights norms and values, on the one hand, and conflict resolution, post–conflict peace-building and reconstruction, on the other. It advances the view both from a theoretical and practical standpoint, that human rights have a role to play throughout the life of any conflict: from the pre-conflict to the post-conflict and reconstruction stages. Identifying entry points for human rights in the pre-conflict stage leading up to the establishment of the rule of law and societal reconstruction after the conflict, this book uses Sierra Leone and Democratic Republic of Congo experiences to illustrate the obstacles, the successes, and the significance of human rights norms to the overall peace agenda in societies afflicted by conflict.
- Full Text: false
Hungry but silent: a content analysis of media reporting on the 2011-2012 famine in Somalia
- Authors: Stupart, Richard
- Date: 2013
- Subjects: Famines -- Political aspects -- Somalia Somalia -- In mass media Famines in mass media
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3500 , http://hdl.handle.net/10962/d1006054
- Description: This dissertation examines media coverage of the 2011- 2012 famine in Somalia by the websites of BBC News, CNN and Al Jazeera. Using both quantitative and qualitative content analyses, it asks why coverage of the famine began as late as it did, despite ample evidence of the coming famine. It further surveys the famine-related news reports for evidence of four paradigms through which the causes of famine can be understood; as a Malthusian competition between population and land, as a failure of food entitlements as conceived of by Sen (1981), as critical political event (Edkins, 2004), or as an issue of criminality (Alex de Waal, 2008). Findings include a dramatic silencing of victim’s accounts of famine, despite a reliance on their photographic images, as well as an overwhelming preference for Malthusian accounts of the famine. Late media coverage is explored via a new-values paradigm which links the sudden outburst of media coverage for the famine to a formal UN declaration, and suggests that this may have created a new elite-relevance to the event which did not exist before, and therefore making it of relevance to domestic publics.
- Full Text:
- Authors: Stupart, Richard
- Date: 2013
- Subjects: Famines -- Political aspects -- Somalia Somalia -- In mass media Famines in mass media
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3500 , http://hdl.handle.net/10962/d1006054
- Description: This dissertation examines media coverage of the 2011- 2012 famine in Somalia by the websites of BBC News, CNN and Al Jazeera. Using both quantitative and qualitative content analyses, it asks why coverage of the famine began as late as it did, despite ample evidence of the coming famine. It further surveys the famine-related news reports for evidence of four paradigms through which the causes of famine can be understood; as a Malthusian competition between population and land, as a failure of food entitlements as conceived of by Sen (1981), as critical political event (Edkins, 2004), or as an issue of criminality (Alex de Waal, 2008). Findings include a dramatic silencing of victim’s accounts of famine, despite a reliance on their photographic images, as well as an overwhelming preference for Malthusian accounts of the famine. Late media coverage is explored via a new-values paradigm which links the sudden outburst of media coverage for the famine to a formal UN declaration, and suggests that this may have created a new elite-relevance to the event which did not exist before, and therefore making it of relevance to domestic publics.
- Full Text:
Hydrellia lagarosiphon Deeming (Diptera: Ephydridae), a potential biological control agent for the submerged aquatic weed, Lagarosiphon major (Ridl.) Moss ex Wager (Hydrocharitaceae)
- Martin, Grant D, Coetzee, Julie A, Baars, Jan-Robert
- Authors: Martin, Grant D , Coetzee, Julie A , Baars, Jan-Robert
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/103912 , vital:32322 , https://doi.org/10.4001/003.021.0118
- Description: The leaf-mining fly, Hydrellia lagarosiphon Deeming (Diptera: Ephydridae), was investigated in its native range in South Africa, to determine its potential as a biological control agent for Lagarosiphon major (Ridl.) Moss ex Wager (Hydrocharitaceae), an invasive submerged macrophyte that is weedy in many parts of the world. The fly was found throughout the indigenous range of the plant in South Africa. High larval abundance was recorded at field sites with nearly all L. major shoots sampled ontaining larvae, with densities of up to 10 larvae per shoot. Adults laid batches of up to 15 eggs, usually on the abaxial sides of L. major leaves. The larvae mined internally, leaving the epidermal tissues of the upper and lower leaves intact. The larvae underwent three instars which took an average of 24 days and pupated within the leaf tissue, from which the adults emerged. Impact studies in the laboratory showed that H. lagarosiphon larval feeding significantly restricted the formation of L. major side branches. Based on its biology and damage caused to the plant, Hydrellia lagarosiphon could be considered as a useful biological control candidate for L. major in countries where the plant is invasive.
- Full Text:
- Authors: Martin, Grant D , Coetzee, Julie A , Baars, Jan-Robert
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/103912 , vital:32322 , https://doi.org/10.4001/003.021.0118
- Description: The leaf-mining fly, Hydrellia lagarosiphon Deeming (Diptera: Ephydridae), was investigated in its native range in South Africa, to determine its potential as a biological control agent for Lagarosiphon major (Ridl.) Moss ex Wager (Hydrocharitaceae), an invasive submerged macrophyte that is weedy in many parts of the world. The fly was found throughout the indigenous range of the plant in South Africa. High larval abundance was recorded at field sites with nearly all L. major shoots sampled ontaining larvae, with densities of up to 10 larvae per shoot. Adults laid batches of up to 15 eggs, usually on the abaxial sides of L. major leaves. The larvae mined internally, leaving the epidermal tissues of the upper and lower leaves intact. The larvae underwent three instars which took an average of 24 days and pupated within the leaf tissue, from which the adults emerged. Impact studies in the laboratory showed that H. lagarosiphon larval feeding significantly restricted the formation of L. major side branches. Based on its biology and damage caused to the plant, Hydrellia lagarosiphon could be considered as a useful biological control candidate for L. major in countries where the plant is invasive.
- Full Text:
Identification and evaluation of key factors for rehabilitation of shores denuded of mussels (Perna perna) along the Transkei Coast, South Africa
- Authors: Macala, Lukholo
- Date: 2013
- Subjects: Mussels -- Ecology -- South Africa -- Transkei , Mussels -- Conservation -- South Africa -- Transkei , Mussels -- Growth -- South Africa -- Transkei , Mussels -- Effect of human beings on -- South Africa -- Transkei , Mussels -- Reproduction -- South Africa -- Transkei , Perna -- South Africa -- Transkei
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5611 , http://hdl.handle.net/10962/d1002966 , Mussels -- Ecology -- South Africa -- Transkei , Mussels -- Conservation -- South Africa -- Transkei , Mussels -- Growth -- South Africa -- Transkei , Mussels -- Effect of human beings on -- South Africa -- Transkei , Mussels -- Reproduction -- South Africa -- Transkei , Perna -- South Africa -- Transkei
- Description: Mussels play an important supplementary role in the diet of local communities on the Transkei coast in the Eastern Cape province of South Africa. The exploitation of mussels date back to about 1350 years ago, but in the last 3 decades, exploitation of the brown mussel Perna perna has become unsustainable with mussels collected as small as 30-40mm when they are only just sexually mature. Dye and Dyantyi (2002) developed a technique to rehabilitate areas denuded of adult mussels. The government sponsored Mussel Rehabilitation Project (MRP) to use this technique but only some sites have been successfully rehabilitated, reaching c. 80 % cover within a year whilst others only reach about 5%. At an unexploited site (Riet River), I tested the effects of mussel size and wave strength on the effectiveness of the rehabilitation technique, hypothesizing that different size classes may respond differently due to differences in their energy allocation (growth vs reproduction), while wave action determines food supply. Small (1-2cm) and large mussels (3-4cm) were deployed for rehabilitation at 2 exposed and 2 sheltered sites, separated by 100s m. A similar study was repeated in Coffee Bay where shores are exploited. Six sites were selected, 3 sites that had been successfully rehabilitated and 3 that were unsuccessful according to the MRP. Again, two size classes were used but these differed from the first experiment. Mussels of 3-4cm size were now rated as small and 5-6cm as large. Two methods were used to re-attach mussels, the original and the same method with the addition of mesh bags during mussel deployment. Treatments were examined on three occasions at approximately one month intervals. At Riet River, the sites chosen did not show differences in wave strength (measured using dynamometers) or water flux (measured using erosion of cement balls) so that water motion was excluded from the analyses. Small mussels grew faster and had weaker attachment than large mussels. There was no difference in condition index between small and large mussels, or in the numbers of recruits settling among the byssus threads of deployed mussels of the two size classes. In Coffee Bay, there was no relationship between rehabilitation success and maximum wave force, and no difference in bulk water flux among sites. Small mussels deployed using mesh bags survived better than non-meshed or large mussels of either treatment. There was no difference in condition index (CI) between mesh and no-mesh, or between small and large mussels. As in the case of Riet River, small mussels grew faster than large mussels, but large mussels attached stronger than small mussels, with no effect of mesh. Although the factors that improve reseeding of mussels can be identified (use of mesh, use of small mussels, choice of sites with high recruitment rates), successful long-term rehabilitation requires appropriate subsequent management of re-seeded sites.
- Full Text:
- Authors: Macala, Lukholo
- Date: 2013
- Subjects: Mussels -- Ecology -- South Africa -- Transkei , Mussels -- Conservation -- South Africa -- Transkei , Mussels -- Growth -- South Africa -- Transkei , Mussels -- Effect of human beings on -- South Africa -- Transkei , Mussels -- Reproduction -- South Africa -- Transkei , Perna -- South Africa -- Transkei
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5611 , http://hdl.handle.net/10962/d1002966 , Mussels -- Ecology -- South Africa -- Transkei , Mussels -- Conservation -- South Africa -- Transkei , Mussels -- Growth -- South Africa -- Transkei , Mussels -- Effect of human beings on -- South Africa -- Transkei , Mussels -- Reproduction -- South Africa -- Transkei , Perna -- South Africa -- Transkei
- Description: Mussels play an important supplementary role in the diet of local communities on the Transkei coast in the Eastern Cape province of South Africa. The exploitation of mussels date back to about 1350 years ago, but in the last 3 decades, exploitation of the brown mussel Perna perna has become unsustainable with mussels collected as small as 30-40mm when they are only just sexually mature. Dye and Dyantyi (2002) developed a technique to rehabilitate areas denuded of adult mussels. The government sponsored Mussel Rehabilitation Project (MRP) to use this technique but only some sites have been successfully rehabilitated, reaching c. 80 % cover within a year whilst others only reach about 5%. At an unexploited site (Riet River), I tested the effects of mussel size and wave strength on the effectiveness of the rehabilitation technique, hypothesizing that different size classes may respond differently due to differences in their energy allocation (growth vs reproduction), while wave action determines food supply. Small (1-2cm) and large mussels (3-4cm) were deployed for rehabilitation at 2 exposed and 2 sheltered sites, separated by 100s m. A similar study was repeated in Coffee Bay where shores are exploited. Six sites were selected, 3 sites that had been successfully rehabilitated and 3 that were unsuccessful according to the MRP. Again, two size classes were used but these differed from the first experiment. Mussels of 3-4cm size were now rated as small and 5-6cm as large. Two methods were used to re-attach mussels, the original and the same method with the addition of mesh bags during mussel deployment. Treatments were examined on three occasions at approximately one month intervals. At Riet River, the sites chosen did not show differences in wave strength (measured using dynamometers) or water flux (measured using erosion of cement balls) so that water motion was excluded from the analyses. Small mussels grew faster and had weaker attachment than large mussels. There was no difference in condition index between small and large mussels, or in the numbers of recruits settling among the byssus threads of deployed mussels of the two size classes. In Coffee Bay, there was no relationship between rehabilitation success and maximum wave force, and no difference in bulk water flux among sites. Small mussels deployed using mesh bags survived better than non-meshed or large mussels of either treatment. There was no difference in condition index (CI) between mesh and no-mesh, or between small and large mussels. As in the case of Riet River, small mussels grew faster than large mussels, but large mussels attached stronger than small mussels, with no effect of mesh. Although the factors that improve reseeding of mussels can be identified (use of mesh, use of small mussels, choice of sites with high recruitment rates), successful long-term rehabilitation requires appropriate subsequent management of re-seeded sites.
- Full Text:
Identity and origins of introduced and native Azolla species in Florida
- Madeira, Paul T, Center, Ted D, Coetzee, Julie A, Pemberton, Robert W, Purcell, Matthew F, Hill, Martin P
- Authors: Madeira, Paul T , Center, Ted D , Coetzee, Julie A , Pemberton, Robert W , Purcell, Matthew F , Hill, Martin P
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419313 , vital:71634 , xlink:href="https://doi.org/10.1016/j.aquabot.2013.07.009"
- Description: Azolla pinnata, an introduced aquatic fern, is spreading rapidly causing concern that it may displace native Azolla. It is now present in the Arthur R. Marshall Loxahatchee National Wildlife Refuge, the northernmost portion of the Florida Everglades. Because A. pinnata subspecies are native to Africa, Southeast Asia, and Australia, determining the actual geographic origin of the Florida exotic is important to the discovery of efficacious biological control agents. Both the exotic and native Azollas were examined using morphological and molecular criteria. Both criteria distinguished three A. pinnata subspecies with the Florida exotic matching the Australian A. pinnata subsp. pinnata. Molecular divergence between the A. pinnata subspecies indicates the three types should be considered separate species. The Florida native was characterized by both molecular and morphological methods as Azolla caroliniana. The discovery of a previously uncharacterized Ecuadorian Azolla, which appears to be a paternal ancestor of A. caroliniana, indicates that A. caroliniana is a hybrid species.
- Full Text:
- Authors: Madeira, Paul T , Center, Ted D , Coetzee, Julie A , Pemberton, Robert W , Purcell, Matthew F , Hill, Martin P
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419313 , vital:71634 , xlink:href="https://doi.org/10.1016/j.aquabot.2013.07.009"
- Description: Azolla pinnata, an introduced aquatic fern, is spreading rapidly causing concern that it may displace native Azolla. It is now present in the Arthur R. Marshall Loxahatchee National Wildlife Refuge, the northernmost portion of the Florida Everglades. Because A. pinnata subspecies are native to Africa, Southeast Asia, and Australia, determining the actual geographic origin of the Florida exotic is important to the discovery of efficacious biological control agents. Both the exotic and native Azollas were examined using morphological and molecular criteria. Both criteria distinguished three A. pinnata subspecies with the Florida exotic matching the Australian A. pinnata subsp. pinnata. Molecular divergence between the A. pinnata subspecies indicates the three types should be considered separate species. The Florida native was characterized by both molecular and morphological methods as Azolla caroliniana. The discovery of a previously uncharacterized Ecuadorian Azolla, which appears to be a paternal ancestor of A. caroliniana, indicates that A. caroliniana is a hybrid species.
- Full Text:
Immobilisation of electric eel acetylcholinesterase on nanofibres electrospun from a nylon and chitosan blend
- Authors: Mafuma, Tendai Simbarashe
- Date: 2013
- Subjects: Acetylcholinesterase Acetylcholinesterase -- Inhibitors Electric eel Biosensors Immobilized enzymes Pesticides -- Environmental aspects Pesticides -- Toxicology Nylon Chitosan Nanofibers Electrospinning
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3886 , http://hdl.handle.net/10962/d1001620
- Description: Organophosphates and carbamates are potent inhibitors of the neurotransmitter acetylcholinesterase. This inhibition results in the blocking of nerve signal transference into the post synaptic neuron leading to loss of muscle action and death. Because of the universal mechanisms of signal transduction in animals, these inhibitors have been widely used as agricultural pesticides as well as chemical warfare agents (nerve agents). Health issues associated with pesticide usage result from the fact that both the pesticides and their breakdown products often end up in water and food sources as well as in the soil. As a result, there has been an increase in the number of studies aimed at the detection of these pesticides in the environment. One popular research area is enzyme based biosensor construction. Some important criteria for consideration during the construction of biosensors are the importance of a suitable solid support as well as the enzyme immobilisation method. Recently, there has been increased interest in using nano-scale material e.g. using nanoparticles as enzyme support material. This is largely due to their advantages such as large surface area to volume ratio as well as reduced mass transfer resistance. Electrospinning is a straight forward and cost effective method for producing nanofibres from any soluble polymer(s). The applications of electrospun nanofibres have been reported in clinical studies, biofuel production as well as bioremediation. In this study two polymers were selected: nylon for its mechanical stability and chitosan for its biocompatibility and hydrophilicity, for the fabrication of electrospun nanofibres which would function as immobilisation support material for acetylcholinesterase. The first objective of this study was to electrospin nanofibres from a nylon-6 and chitosan blend solution. A binary solvent system consisting of formic acid and acetic acid (50:50) successfully dissolved and blended the polymers which were subsequently electrospun. Scanning electron microscopy characterisation of the nanofibres showed that (i) a nylon-6: chitosan ratio of 16%: 3% resulted in the formation of bead free nanofibres and (ii) the fibres were collected in non-woven mats characterised by different size nanofibres with average diameters of 250 nm for the main fibres and 40 nm for the smaller nanofibres. Fourier transform infra-red (FT-IR) analysis of the nanofibres indicated that a new product had been formed during the blending of the two polymers. The second aim of the study was to carry out a facile immobilisation of electric eel acetylcholinesterase via glutaraldehyde (GA) cross-linking. Glutaraldehyde solution 5% (v/v) resulted in the immobilisation of 0.334 mg/cm² of acetylcholinesterase onto the nanofibres. The immobilisation procedure was optimised with reference to acetylcholinestease and crosslinker concentrations, incubation time and the cross-linking method. A comparative investigation into the optimum pH and temperature conditions, pH and thermal stabilities, substrate and inhibition kinetics was then carried out on free and immobilised acetylcholinesterase. The final objective of this study was to determine the storage stabilities of the immobilised and free enzymes as well as the reusability characteristics of the immobilised acetylcholinesterase. Several conclusions were drawn from this study. Acetylcholinesterase was successfully immobilised onto the surface of nylon-6:chitosan nanofibres with retention of its activity. There was a shift in the pH optimum of the immobilised acetylcholineseterase by 0.5 units towards a neutral pH. Although both free and immobilised acetylcholinesterase exhibited the same optimum temperature, immobilised acetylcholinesterase showed enhanced thermal stability. In terms of pH stability, immobilised acetylcholinesterase showed greater stability at acidic pH whilst free acetylcholinesterase was more stable under alkaline pH conditions. Relative to free acetylcholinesterase, the immobilised enzyme showed considerable storage stability retaining ~50% of its activity when stored for 49 days at 4°C. Immobilised acetylcholinesterase also retained > 20% of its initial activity after 9 consecutive reuse cycles. When exposed to fixed concentrations of carbofuran or demeton-S-methyl sulfone, immobilised acetylcholinesterase showed similar inhibition characteristics to that of the free enzyme. The decrease in enzyme activity observed after immobilisation to the nanofibres may have been due to several reasons which include some enzyme molecules being immobilised in structural conformations which reduced substrate access to the catalytic site, participation of the catalytic residues in immobilisation and enzyme denaturation due to the reaction conditions used for acetylcholinesterase immobilisation. Similar observations have been widely reported in literature and this is one of the major drawbacks of enzyme immobilisation. In conclusion, nylon-6:chitosan electrospun nanofibres were shown to be suitable supports for facile acetylcholinesterase immobilisation and the immobilised enzyme has potential for use in pesticide detection. Future recommendations for this study include a comparative study of the GA cross-linking method for AChE immobilisation which will lead to more intensely bound enzyme molecules to prevent non-specific binding. An investigation into the effect of inhibitors on stored immobilised AChE, as well as reactivation and reuse studies, may also be useful for determining the cost-effectiveness of reusing immobilised AChE for pesticide detection in environmental water samples. Several models have been designed for the determination of the kinetic parameters for immobilised enzymes. These take into account the mass transfer resistance as well as the overall charge of the immobilisation matrix. The use of these models to analyse experimental data will give a clear understanding of the effects of immobilisation on enzyme activity
- Full Text:
- Authors: Mafuma, Tendai Simbarashe
- Date: 2013
- Subjects: Acetylcholinesterase Acetylcholinesterase -- Inhibitors Electric eel Biosensors Immobilized enzymes Pesticides -- Environmental aspects Pesticides -- Toxicology Nylon Chitosan Nanofibers Electrospinning
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3886 , http://hdl.handle.net/10962/d1001620
- Description: Organophosphates and carbamates are potent inhibitors of the neurotransmitter acetylcholinesterase. This inhibition results in the blocking of nerve signal transference into the post synaptic neuron leading to loss of muscle action and death. Because of the universal mechanisms of signal transduction in animals, these inhibitors have been widely used as agricultural pesticides as well as chemical warfare agents (nerve agents). Health issues associated with pesticide usage result from the fact that both the pesticides and their breakdown products often end up in water and food sources as well as in the soil. As a result, there has been an increase in the number of studies aimed at the detection of these pesticides in the environment. One popular research area is enzyme based biosensor construction. Some important criteria for consideration during the construction of biosensors are the importance of a suitable solid support as well as the enzyme immobilisation method. Recently, there has been increased interest in using nano-scale material e.g. using nanoparticles as enzyme support material. This is largely due to their advantages such as large surface area to volume ratio as well as reduced mass transfer resistance. Electrospinning is a straight forward and cost effective method for producing nanofibres from any soluble polymer(s). The applications of electrospun nanofibres have been reported in clinical studies, biofuel production as well as bioremediation. In this study two polymers were selected: nylon for its mechanical stability and chitosan for its biocompatibility and hydrophilicity, for the fabrication of electrospun nanofibres which would function as immobilisation support material for acetylcholinesterase. The first objective of this study was to electrospin nanofibres from a nylon-6 and chitosan blend solution. A binary solvent system consisting of formic acid and acetic acid (50:50) successfully dissolved and blended the polymers which were subsequently electrospun. Scanning electron microscopy characterisation of the nanofibres showed that (i) a nylon-6: chitosan ratio of 16%: 3% resulted in the formation of bead free nanofibres and (ii) the fibres were collected in non-woven mats characterised by different size nanofibres with average diameters of 250 nm for the main fibres and 40 nm for the smaller nanofibres. Fourier transform infra-red (FT-IR) analysis of the nanofibres indicated that a new product had been formed during the blending of the two polymers. The second aim of the study was to carry out a facile immobilisation of electric eel acetylcholinesterase via glutaraldehyde (GA) cross-linking. Glutaraldehyde solution 5% (v/v) resulted in the immobilisation of 0.334 mg/cm² of acetylcholinesterase onto the nanofibres. The immobilisation procedure was optimised with reference to acetylcholinestease and crosslinker concentrations, incubation time and the cross-linking method. A comparative investigation into the optimum pH and temperature conditions, pH and thermal stabilities, substrate and inhibition kinetics was then carried out on free and immobilised acetylcholinesterase. The final objective of this study was to determine the storage stabilities of the immobilised and free enzymes as well as the reusability characteristics of the immobilised acetylcholinesterase. Several conclusions were drawn from this study. Acetylcholinesterase was successfully immobilised onto the surface of nylon-6:chitosan nanofibres with retention of its activity. There was a shift in the pH optimum of the immobilised acetylcholineseterase by 0.5 units towards a neutral pH. Although both free and immobilised acetylcholinesterase exhibited the same optimum temperature, immobilised acetylcholinesterase showed enhanced thermal stability. In terms of pH stability, immobilised acetylcholinesterase showed greater stability at acidic pH whilst free acetylcholinesterase was more stable under alkaline pH conditions. Relative to free acetylcholinesterase, the immobilised enzyme showed considerable storage stability retaining ~50% of its activity when stored for 49 days at 4°C. Immobilised acetylcholinesterase also retained > 20% of its initial activity after 9 consecutive reuse cycles. When exposed to fixed concentrations of carbofuran or demeton-S-methyl sulfone, immobilised acetylcholinesterase showed similar inhibition characteristics to that of the free enzyme. The decrease in enzyme activity observed after immobilisation to the nanofibres may have been due to several reasons which include some enzyme molecules being immobilised in structural conformations which reduced substrate access to the catalytic site, participation of the catalytic residues in immobilisation and enzyme denaturation due to the reaction conditions used for acetylcholinesterase immobilisation. Similar observations have been widely reported in literature and this is one of the major drawbacks of enzyme immobilisation. In conclusion, nylon-6:chitosan electrospun nanofibres were shown to be suitable supports for facile acetylcholinesterase immobilisation and the immobilised enzyme has potential for use in pesticide detection. Future recommendations for this study include a comparative study of the GA cross-linking method for AChE immobilisation which will lead to more intensely bound enzyme molecules to prevent non-specific binding. An investigation into the effect of inhibitors on stored immobilised AChE, as well as reactivation and reuse studies, may also be useful for determining the cost-effectiveness of reusing immobilised AChE for pesticide detection in environmental water samples. Several models have been designed for the determination of the kinetic parameters for immobilised enzymes. These take into account the mass transfer resistance as well as the overall charge of the immobilisation matrix. The use of these models to analyse experimental data will give a clear understanding of the effects of immobilisation on enzyme activity
- Full Text:
Impact of insecticides on the reproductive potential of false codling moth, Thaumatotibia leucotreta (Meyrick, 1913)(Lepidoptera: Tortricidae)
- Authors: Fullard, T , Hill, Martin P
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406092 , vital:70238 , xlink:href="https://hdl.handle.net/10520/EJC141302"
- Description: False codling moth, Thaumatotibia leucotreta(Meyrick, 1913) (Lepidoptera: Tortricidae), is animportant pest on citrus in South Africa. Several new insecticides were screened for theirpotential negative impacts onT. leucotreta’s reproduction through topical insecticide applica-tions and detached fruit bioassays. Detached fruit bioassays showed that the registeredstandard concentration of Delegate®20 g/100 l and DPX-HGW86 35 ml/100 l caused femalesto oviposit significantly fewer eggs (P= 0.0016) than the controls. The same was found forthe registered concentration of Coragen® (P is less than 0.0001). Topical insecticide trials showed thatonly concentrations of Coragen®, at the registered field rate and above had an effect on themoths’ reproductive output (P is less than 0.0001). Alsystin®and Meothrin™, which were used asindustry standards, did not negatively affect the reproductive output of the moths duringtopical or detached fruit bioassay trials. This study helps to better understand the impor-tance of the application mode,i.e.directly on moths or fruit and implies secondary benefits tosome insecticide applications.
- Full Text:
- Authors: Fullard, T , Hill, Martin P
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/406092 , vital:70238 , xlink:href="https://hdl.handle.net/10520/EJC141302"
- Description: False codling moth, Thaumatotibia leucotreta(Meyrick, 1913) (Lepidoptera: Tortricidae), is animportant pest on citrus in South Africa. Several new insecticides were screened for theirpotential negative impacts onT. leucotreta’s reproduction through topical insecticide applica-tions and detached fruit bioassays. Detached fruit bioassays showed that the registeredstandard concentration of Delegate®20 g/100 l and DPX-HGW86 35 ml/100 l caused femalesto oviposit significantly fewer eggs (P= 0.0016) than the controls. The same was found forthe registered concentration of Coragen® (P is less than 0.0001). Topical insecticide trials showed thatonly concentrations of Coragen®, at the registered field rate and above had an effect on themoths’ reproductive output (P is less than 0.0001). Alsystin®and Meothrin™, which were used asindustry standards, did not negatively affect the reproductive output of the moths duringtopical or detached fruit bioassay trials. This study helps to better understand the impor-tance of the application mode,i.e.directly on moths or fruit and implies secondary benefits tosome insecticide applications.
- Full Text:
Impacts of a sub-lethal dose of glyphosate on water hyacinth nutrients and its indirect effects on Neochetina weevils
- Katembo, Naweji, Hill, Martin P, Byrne, Marcus J
- Authors: Katembo, Naweji , Hill, Martin P , Byrne, Marcus J
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417726 , vital:71481 , xlink:href="https://doi.org/10.1080/09583157.2013.839982"
- Description: A sub-lethal dose of a herbicide under field conditions was applied to determine if it stimulates an increase in water hyacinth nutrients, thereby increasing feeding intensity by Neochetina spp. weevils used as biocontrol agents of the weed. Nitrogen (N) and carbon (C) were measured and compared between sprayed plants and control plants. At one site (Delta Park), N levels were lower in the sprayed plants compared to the control plants both in the leaves and the crown. At the second site (Farm Dam), leaf N was also lower in the sprayed plants than in the control plants, while no difference was found in crown N. Mean number of feeding scars per cm2 at Delta Park was significantly higher on the sprayed plants compared to the control plants, while no significant difference was found at Farm Dam. At Delta Park, there was no correlation, however, between the number of weevil feeding scars and leaf N or C:N ratio in sprayed plants. In conclusion, the sub-lethal dose of glyphosate did not directly result in an increase in weevil feeding intensity but it can be recommended in an integrated control system to retard water hyacinth growth while conserving the weevil population.
- Full Text:
- Authors: Katembo, Naweji , Hill, Martin P , Byrne, Marcus J
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/417726 , vital:71481 , xlink:href="https://doi.org/10.1080/09583157.2013.839982"
- Description: A sub-lethal dose of a herbicide under field conditions was applied to determine if it stimulates an increase in water hyacinth nutrients, thereby increasing feeding intensity by Neochetina spp. weevils used as biocontrol agents of the weed. Nitrogen (N) and carbon (C) were measured and compared between sprayed plants and control plants. At one site (Delta Park), N levels were lower in the sprayed plants compared to the control plants both in the leaves and the crown. At the second site (Farm Dam), leaf N was also lower in the sprayed plants than in the control plants, while no difference was found in crown N. Mean number of feeding scars per cm2 at Delta Park was significantly higher on the sprayed plants compared to the control plants, while no significant difference was found at Farm Dam. At Delta Park, there was no correlation, however, between the number of weevil feeding scars and leaf N or C:N ratio in sprayed plants. In conclusion, the sub-lethal dose of glyphosate did not directly result in an increase in weevil feeding intensity but it can be recommended in an integrated control system to retard water hyacinth growth while conserving the weevil population.
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Implementation of AES-64 connection management for Ethernet Audio/Video Bridging devices
- Dibley, James, Foss, Richard
- Authors: Dibley, James , Foss, Richard
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426875 , vital:72397 , https://www.aes.org/e-lib/online/browse.cfm?elib=17014
- Description: AES-64 is a standard for the discovery, enumeration, connection management, and control of multimedia network devices. This paper describes the implementation of an AES-64 protocol stack and control application on devices that support the IEEE Ethernet Audio/Video Bridging standards for streaming multimedia, enabling connection management of network audio streams.
- Full Text:
- Authors: Dibley, James , Foss, Richard
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/426875 , vital:72397 , https://www.aes.org/e-lib/online/browse.cfm?elib=17014
- Description: AES-64 is a standard for the discovery, enumeration, connection management, and control of multimedia network devices. This paper describes the implementation of an AES-64 protocol stack and control application on devices that support the IEEE Ethernet Audio/Video Bridging standards for streaming multimedia, enabling connection management of network audio streams.
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In search of the Holy Grail: youth media consumption and the construction of citizenship
- Authors: Steenveld, Lynette N
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158597 , vital:40210 , https://hdl.handle.net/10520/EJC141601
- Description: Rather than support the democratic process, as in the ideal scheme of things it should be doing, journalism has become an alienating, cynicism-inducing, narcoticising force in our political culture, turning people off citizenship rather than equipping them to fulfil their democratic potential.
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- Authors: Steenveld, Lynette N
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158597 , vital:40210 , https://hdl.handle.net/10520/EJC141601
- Description: Rather than support the democratic process, as in the ideal scheme of things it should be doing, journalism has become an alienating, cynicism-inducing, narcoticising force in our political culture, turning people off citizenship rather than equipping them to fulfil their democratic potential.
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In-silico analysis of Plasmodium falciparum Hop protein and its interactions with Hsp70 and Hsp90
- Authors: Clitheroe, Crystal-Leigh
- Date: 2013
- Subjects: Plasmodium falciparum , Heat shock proteins , Molecular chaperones , Homology (Biology) , Protein-protein interactions , Malaria -- Chemotherapy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3896 , http://hdl.handle.net/10962/d1003819 , Plasmodium falciparum , Heat shock proteins , Molecular chaperones , Homology (Biology) , Protein-protein interactions , Malaria -- Chemotherapy
- Description: A lessor understood co-chaperone, the Hsp70/Hsp90 organising protein (Hop), has been found to play an important role in modulating the activity and co-interaction of two essential chaperones; Hsp90 and Hsp70. The best understood aspects of Hop so far indicate that residues in the concave surfaces of the three tetratricopeptide repeat (TPR) domains in the protein bind selectively to the C-terminal motifs of Hsp70 and Hsp90. Recent research suggests that P. falciparum Hop (PfHop), PfHsp90 and PfHsp70 do interact and form complex in the P. falciparum trophozooite and are overexpressed in this infective stage. However, there has been almost no computational research on malarial Hop protein in complex with other malarial Hsps.The current work has focussed on several aspects of the in-silico characterisation of PfHop, including an in-depth multiple sequence alignment and phylogenetic analysis of the protein; which showed that Hop is very well conserved across a wide range of available phyla (four Kingdoms, 60 species). Homology modelling was employed to predict several protein structures for these interactions in P. falciparum, as well as predict structures of the relevant TPR domains of Human Hop (HsHop) in complex with its own Hsp90 and Hsp70 C-terminal peptide partners for comparison. Protein complex interaction analyses indicate that concave TPR sites bound to the C-terminal motifs of partner proteins are very similar in both species, due to the excellent conservation of the TPR domain’s “double carboxylate binding clamp”. Motif analysis was combined with phylogenetic trees and structure mapping in novel ways to attain more information on the evolutionary conservation of important structural and functional sites on Hop. Alternative sites of interaction between Hop TPR2 and Hsp90’s M and C domains are distinctly less well conserved between the two species, but still important to complex formation, making this a likely interaction site for selective drug targeting. Binding and interaction energies for all modelled complexes have been calculated; indicating that all HsHop TPR domains have higher affinities for their respective C-terminal partners than do their P. falciparum counterparts. An alternate motif corresponding to the C-terminal motif of PfHsp70-x (exported to the infected erythrocyte cytosol) in complex with both human and malarial TPR1 and TPR2B domains was analysed, and these studies suggest that the human TPR domains have a higher affinity for this motif than do the respective PfHop TPR domains. This may indicate potential for a cross species protein interaction to take place, as PfHop is not transported to the human erythrocyte cytosol.
- Full Text:
- Authors: Clitheroe, Crystal-Leigh
- Date: 2013
- Subjects: Plasmodium falciparum , Heat shock proteins , Molecular chaperones , Homology (Biology) , Protein-protein interactions , Malaria -- Chemotherapy
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3896 , http://hdl.handle.net/10962/d1003819 , Plasmodium falciparum , Heat shock proteins , Molecular chaperones , Homology (Biology) , Protein-protein interactions , Malaria -- Chemotherapy
- Description: A lessor understood co-chaperone, the Hsp70/Hsp90 organising protein (Hop), has been found to play an important role in modulating the activity and co-interaction of two essential chaperones; Hsp90 and Hsp70. The best understood aspects of Hop so far indicate that residues in the concave surfaces of the three tetratricopeptide repeat (TPR) domains in the protein bind selectively to the C-terminal motifs of Hsp70 and Hsp90. Recent research suggests that P. falciparum Hop (PfHop), PfHsp90 and PfHsp70 do interact and form complex in the P. falciparum trophozooite and are overexpressed in this infective stage. However, there has been almost no computational research on malarial Hop protein in complex with other malarial Hsps.The current work has focussed on several aspects of the in-silico characterisation of PfHop, including an in-depth multiple sequence alignment and phylogenetic analysis of the protein; which showed that Hop is very well conserved across a wide range of available phyla (four Kingdoms, 60 species). Homology modelling was employed to predict several protein structures for these interactions in P. falciparum, as well as predict structures of the relevant TPR domains of Human Hop (HsHop) in complex with its own Hsp90 and Hsp70 C-terminal peptide partners for comparison. Protein complex interaction analyses indicate that concave TPR sites bound to the C-terminal motifs of partner proteins are very similar in both species, due to the excellent conservation of the TPR domain’s “double carboxylate binding clamp”. Motif analysis was combined with phylogenetic trees and structure mapping in novel ways to attain more information on the evolutionary conservation of important structural and functional sites on Hop. Alternative sites of interaction between Hop TPR2 and Hsp90’s M and C domains are distinctly less well conserved between the two species, but still important to complex formation, making this a likely interaction site for selective drug targeting. Binding and interaction energies for all modelled complexes have been calculated; indicating that all HsHop TPR domains have higher affinities for their respective C-terminal partners than do their P. falciparum counterparts. An alternate motif corresponding to the C-terminal motif of PfHsp70-x (exported to the infected erythrocyte cytosol) in complex with both human and malarial TPR1 and TPR2B domains was analysed, and these studies suggest that the human TPR domains have a higher affinity for this motif than do the respective PfHop TPR domains. This may indicate potential for a cross species protein interaction to take place, as PfHop is not transported to the human erythrocyte cytosol.
- Full Text: