Rugby : more than just a game : a study of the cumulative effects of mild head injuries on high school rugby players
- Authors: Giai-Coletti, Cristina
- Date: 2013-05-24
- Subjects: Head -- Wounds and injuries -- Complications Rugby football injuries Brain -- Concussion -- Complications Neuropsychological tests
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3175 , http://hdl.handle.net/10962/d1007809
- Description: The present study comprises part of an ongoing research study investigating the effects 0 f cumulative mild head injuries 0 n Rugby Union p layers. The aim 0 f t he study was to ascertain whether there are neuropsychological effects of cumulative mild head injuries sustained during the rugby-playing careers of senior schoolboy rugby players. Participants were top-level rugby players from high schools in Grahamstown and Cape Town (n = 79) and non-contact sport controls of top-level field hockey players from the same schools (n = 58). Group mean comparisons across a battery of neuropsychological tests were carried out between the Total Rugby versus the Total Field Hockey group, and the Rugby Forwards versus the Rugby Backs group. Comparisons between Total Rugby versus Total Field Hockey revealed impaired performance by the rugby players on two tests of visuoperceptual tracking, namely Digit Symbol Substitution and Trail Making Test (Part A). For Rugby Forwards versus Rugby Backs, there were no consistent differences to support the expectation that forwards would perform worse than backs. Forwards performed more poorly than backs on WMS Associate Learning Subtest - Hard (Delayed Recall), whereas backs performed more poorly than forwards on Digits Backwards. This suggests that some individuals in the cohort were starting to exhibit verbal memory deficit, albeit not clearly in association with forward positional play. Overall, results of the present study provide tentative support for the hypothesis that school level rugby players are more susceptible to the effects of cumulative concussive and sub-concussive head injuries than are non-contact sport controls. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Authors: Giai-Coletti, Cristina
- Date: 2013-05-24
- Subjects: Head -- Wounds and injuries -- Complications Rugby football injuries Brain -- Concussion -- Complications Neuropsychological tests
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3175 , http://hdl.handle.net/10962/d1007809
- Description: The present study comprises part of an ongoing research study investigating the effects 0 f cumulative mild head injuries 0 n Rugby Union p layers. The aim 0 f t he study was to ascertain whether there are neuropsychological effects of cumulative mild head injuries sustained during the rugby-playing careers of senior schoolboy rugby players. Participants were top-level rugby players from high schools in Grahamstown and Cape Town (n = 79) and non-contact sport controls of top-level field hockey players from the same schools (n = 58). Group mean comparisons across a battery of neuropsychological tests were carried out between the Total Rugby versus the Total Field Hockey group, and the Rugby Forwards versus the Rugby Backs group. Comparisons between Total Rugby versus Total Field Hockey revealed impaired performance by the rugby players on two tests of visuoperceptual tracking, namely Digit Symbol Substitution and Trail Making Test (Part A). For Rugby Forwards versus Rugby Backs, there were no consistent differences to support the expectation that forwards would perform worse than backs. Forwards performed more poorly than backs on WMS Associate Learning Subtest - Hard (Delayed Recall), whereas backs performed more poorly than forwards on Digits Backwards. This suggests that some individuals in the cohort were starting to exhibit verbal memory deficit, albeit not clearly in association with forward positional play. Overall, results of the present study provide tentative support for the hypothesis that school level rugby players are more susceptible to the effects of cumulative concussive and sub-concussive head injuries than are non-contact sport controls. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
South African women's literature and the ecofeminist perspective
- Authors: Ewing, Maureen Colleen
- Date: 2013-05-24
- Subjects: Ecofeminism in literature Ecology in literature Nature in literature South African fiction -- History and criticism Smith, Pauline, 1883-1959 Schreiner, Olive, 1855-1920 Matthee, Dalene, 1938-2005 Poland, Marguerite
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2287 , http://hdl.handle.net/10962/d1007808
- Description: A social-constructionist ecofeminist perspective argues that patriarchal society separates the human (or culture) from nature, which causes a false assumption that humanity possesses the right, as a superior species, to dominate nature. This perspective integrates the domination of nature with social conflicts, including but not limited to racial discrimination, gender oppression, and class hierarchies. Understanding how these various forms of oppression interrelate forms the main goal of an ecofeminist perspective. Since the nature-culture, female-male, and whitenonwhite conflicts resonate and interlock throughout South Africa's history, socialconstructionist ecofeminism is an indispensable perspective for analysing South African literature. This thesis takes a social-constructionist ecofeminist approach and applies it to four women authors that write about South African society between the years 1860-1900. This thesis includes the following authors and their works: Olive Schreiner (1855-1920) and two of her novels, The Story of an African Farm (1883) and From Man to Man (published posthumously in 1927); Pauline Smith (1882-1959) and her novel The Beadle (1926); Dalene Matthee (1938- ) and three of her novels, Circles in a Forest (1984), Fiela's Child (1986), and The Mulberry Forest (1987); and Marguerite Poland (1950- ) and one of her novels, Shades (1993). This thesis investigates two women from the time period (Schreiner and Smith) and two women from a late twentieth century perspective (Matthee and Poland) and compares how they depict the natural environment, how they construct gender, and how they interpret class and race power struggles. This thesis concludes that the social-constructionist perspective offers unique insights into these four authors. Schreiner's novels reveal her concerns about gender and racial conflicts in South Africa and her understanding of the nature-culture dichotomy as sustained by Social Darwinism. Smith offers insights into the complex power structures in a rural Afrikaans society that keep women and nonwhite races silent. Matthee writes nature as an active participant in her novels; the social and ecological conflicts emphasise the transformation of the Knysna area. Poland explores the racial tensions, gender conflicts, and environmental concerns that preceded the South African War. Schreiner, Smith, Matthee, and Poland make up a small cross-section of South African literature, but they provide a basis for further discussing the ecofeminist perspective within a South African context. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Authors: Ewing, Maureen Colleen
- Date: 2013-05-24
- Subjects: Ecofeminism in literature Ecology in literature Nature in literature South African fiction -- History and criticism Smith, Pauline, 1883-1959 Schreiner, Olive, 1855-1920 Matthee, Dalene, 1938-2005 Poland, Marguerite
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2287 , http://hdl.handle.net/10962/d1007808
- Description: A social-constructionist ecofeminist perspective argues that patriarchal society separates the human (or culture) from nature, which causes a false assumption that humanity possesses the right, as a superior species, to dominate nature. This perspective integrates the domination of nature with social conflicts, including but not limited to racial discrimination, gender oppression, and class hierarchies. Understanding how these various forms of oppression interrelate forms the main goal of an ecofeminist perspective. Since the nature-culture, female-male, and whitenonwhite conflicts resonate and interlock throughout South Africa's history, socialconstructionist ecofeminism is an indispensable perspective for analysing South African literature. This thesis takes a social-constructionist ecofeminist approach and applies it to four women authors that write about South African society between the years 1860-1900. This thesis includes the following authors and their works: Olive Schreiner (1855-1920) and two of her novels, The Story of an African Farm (1883) and From Man to Man (published posthumously in 1927); Pauline Smith (1882-1959) and her novel The Beadle (1926); Dalene Matthee (1938- ) and three of her novels, Circles in a Forest (1984), Fiela's Child (1986), and The Mulberry Forest (1987); and Marguerite Poland (1950- ) and one of her novels, Shades (1993). This thesis investigates two women from the time period (Schreiner and Smith) and two women from a late twentieth century perspective (Matthee and Poland) and compares how they depict the natural environment, how they construct gender, and how they interpret class and race power struggles. This thesis concludes that the social-constructionist perspective offers unique insights into these four authors. Schreiner's novels reveal her concerns about gender and racial conflicts in South Africa and her understanding of the nature-culture dichotomy as sustained by Social Darwinism. Smith offers insights into the complex power structures in a rural Afrikaans society that keep women and nonwhite races silent. Matthee writes nature as an active participant in her novels; the social and ecological conflicts emphasise the transformation of the Knysna area. Poland explores the racial tensions, gender conflicts, and environmental concerns that preceded the South African War. Schreiner, Smith, Matthee, and Poland make up a small cross-section of South African literature, but they provide a basis for further discussing the ecofeminist perspective within a South African context. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
A phenomenological study of how South African entrepreneurs experience and deal with ethical dilemmas
- Authors: Robinson, David Alan
- Date: 2003
- Subjects: Entrepreneurship -- South Africa Business ethics -- South Africa Decision making -- Moral and ethical aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1175 , http://hdl.handle.net/10962/d1002791
- Description: This research sets out to examine how entrepreneurs experience and deal with ethical dilemmas. An entrepreneur is defined as a person who creates something of value and assumes the risk of establishing and managing a business around it. An ethical dilemma comes about when the entrepreneur must choose between alternatives and where the morally correct choice is unclear. This may be due to conflicting personal values or loyalties, tensions arising out of the realization that the moral action is not in line with his self-interest, cross-cultural conflict, or moral ambiguity. Because of the nature of entrepreneurship, the entrepreneur typically lives with ever-present threats arising from limited resources, competition, and the risk of business failure. His actions must simultaneously ensure survival, maximize profit, limit risk, counter threats, optimize the use of resources, and reward him with a feeling of satisfaction. It is hardly surprising that conflicting priorities sometimes ensue. It is also widely believed that these entrepreneurial pursuits supersede the more general need to act in morally appropriate ways. This is a phenomenological study, based on interviews with seven entrepreneurs in established service-oriented ventures. They were asked to describe their business, any dilemmas they have experienced, how they were handled, and what challenges they experience as entrepreneurs in South Africa today. Using phenomenology as my vehicle for data collection and analysis, I sought to enter the lived-worlds of my participants to discover the essence of how ethical dilemmas are experienced in the entrepreneurial milieu. The study’s findings reflect that each entrepreneur has a distinctive world-view, which is represented by a complex mosaic of virtue ethics, deontology, utilitarianism and metaethical perspectives. The permutations are numerous, thus negating the possibility of typecasting entrepreneurs. Instead this research introduces the reader to aspects of entrepreneurial reality such as the complexity of cultural diversity, the freedom to limit the amount of personal energy given to business, and the existence of a more sensitive, searching inner soul beneath the apparent hard-nosed business-oriented public image. While examining entrepreneurial dilemmas in depth, this research introduces the dilemma drum as a tool to portray the argument form of any dilemma by making explicit the ethical component inherent in every business decision and facilitating its effective resolution in a non-prescriptive way. The findings identify certain individual characteristics of participant entrepreneurs that are unlike anything in the mainstream literature, dispelling notions of the entrepreneur as a societal misfit, an essential innovator with vision and flair, or a compulsive risk-taker, while confirming success as the key motivator rather than money per se, the importance of significant others, and the influence of culture and gender. They provide fresh insights into the psyche of the entrepreneur, which include: the existence of inner conviction - marrying the concept of goal-directedness with that of making a contribution to society; exercising the virtues in order to support a delicate balance between business and ethical imperatives; learning to respect energy flow; an alternative morality based on attracting and allowing benevolent or serendipitous events to happen naturally and redefining success as ‘being able to create what is needed as and when needed’; focusing one’s energy on the telos; developing a personal marketing formula suited to a culturallydiverse society; and the anxiety associated with being out-there on one’s own. The general statement, which is ultimately distilled from the seven situated descriptions, introduces a theory of entrepreneurial ethics that presents a new and different view of the lived-world of entrepreneurship, consisting of: Firstly, the key components of entrepreneurial success – having clear goals, energy, making a contribution to society, being connected, getting others on board, and work as an extension of self; secondly, what drives entrepreneurs – goal-orientation, sense of personal excitement, inner conviction, autonomy, and external recognition of success; thirdly, the entrepreneurial ethic – concern for credibility, commitment to service, contributing to quality of life; fourthly, the nature of entrepreneurial dilemmas - conflicting responsibilities, authenticity and credibility, risk and expansion, and awareness of diversity; fifthly, how entrepreneurs deal with ethical issues in their own distinctive ways – by holding fast to authentic virtues, bowing to community expectations, avoiding friction, adopting a ‘come-what-may’ or ‘what’s in it for me’ attitude, or pursuing a higher purpose where both parties benefit; sixthly, entrepreneurs’ world -views – beliefs, goals, ways of deriving satisfaction, virtuous behaviour; pen-ultimately, the challenges facing entrepreneurs in South Africa – overcoming the legacies of apartheid, containing crime, fostering an acceptable business ethic, and facilitating reconciliation between ethnic groups; and lastly, finding the power within – that illusive entrepreneurial spirit – self-reliance, looking beyond immediate obstacles, grasping opportunities, and understanding serendipity.
- Full Text:
- Date Issued: 2003
- Authors: Robinson, David Alan
- Date: 2003
- Subjects: Entrepreneurship -- South Africa Business ethics -- South Africa Decision making -- Moral and ethical aspects
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1175 , http://hdl.handle.net/10962/d1002791
- Description: This research sets out to examine how entrepreneurs experience and deal with ethical dilemmas. An entrepreneur is defined as a person who creates something of value and assumes the risk of establishing and managing a business around it. An ethical dilemma comes about when the entrepreneur must choose between alternatives and where the morally correct choice is unclear. This may be due to conflicting personal values or loyalties, tensions arising out of the realization that the moral action is not in line with his self-interest, cross-cultural conflict, or moral ambiguity. Because of the nature of entrepreneurship, the entrepreneur typically lives with ever-present threats arising from limited resources, competition, and the risk of business failure. His actions must simultaneously ensure survival, maximize profit, limit risk, counter threats, optimize the use of resources, and reward him with a feeling of satisfaction. It is hardly surprising that conflicting priorities sometimes ensue. It is also widely believed that these entrepreneurial pursuits supersede the more general need to act in morally appropriate ways. This is a phenomenological study, based on interviews with seven entrepreneurs in established service-oriented ventures. They were asked to describe their business, any dilemmas they have experienced, how they were handled, and what challenges they experience as entrepreneurs in South Africa today. Using phenomenology as my vehicle for data collection and analysis, I sought to enter the lived-worlds of my participants to discover the essence of how ethical dilemmas are experienced in the entrepreneurial milieu. The study’s findings reflect that each entrepreneur has a distinctive world-view, which is represented by a complex mosaic of virtue ethics, deontology, utilitarianism and metaethical perspectives. The permutations are numerous, thus negating the possibility of typecasting entrepreneurs. Instead this research introduces the reader to aspects of entrepreneurial reality such as the complexity of cultural diversity, the freedom to limit the amount of personal energy given to business, and the existence of a more sensitive, searching inner soul beneath the apparent hard-nosed business-oriented public image. While examining entrepreneurial dilemmas in depth, this research introduces the dilemma drum as a tool to portray the argument form of any dilemma by making explicit the ethical component inherent in every business decision and facilitating its effective resolution in a non-prescriptive way. The findings identify certain individual characteristics of participant entrepreneurs that are unlike anything in the mainstream literature, dispelling notions of the entrepreneur as a societal misfit, an essential innovator with vision and flair, or a compulsive risk-taker, while confirming success as the key motivator rather than money per se, the importance of significant others, and the influence of culture and gender. They provide fresh insights into the psyche of the entrepreneur, which include: the existence of inner conviction - marrying the concept of goal-directedness with that of making a contribution to society; exercising the virtues in order to support a delicate balance between business and ethical imperatives; learning to respect energy flow; an alternative morality based on attracting and allowing benevolent or serendipitous events to happen naturally and redefining success as ‘being able to create what is needed as and when needed’; focusing one’s energy on the telos; developing a personal marketing formula suited to a culturallydiverse society; and the anxiety associated with being out-there on one’s own. The general statement, which is ultimately distilled from the seven situated descriptions, introduces a theory of entrepreneurial ethics that presents a new and different view of the lived-world of entrepreneurship, consisting of: Firstly, the key components of entrepreneurial success – having clear goals, energy, making a contribution to society, being connected, getting others on board, and work as an extension of self; secondly, what drives entrepreneurs – goal-orientation, sense of personal excitement, inner conviction, autonomy, and external recognition of success; thirdly, the entrepreneurial ethic – concern for credibility, commitment to service, contributing to quality of life; fourthly, the nature of entrepreneurial dilemmas - conflicting responsibilities, authenticity and credibility, risk and expansion, and awareness of diversity; fifthly, how entrepreneurs deal with ethical issues in their own distinctive ways – by holding fast to authentic virtues, bowing to community expectations, avoiding friction, adopting a ‘come-what-may’ or ‘what’s in it for me’ attitude, or pursuing a higher purpose where both parties benefit; sixthly, entrepreneurs’ world -views – beliefs, goals, ways of deriving satisfaction, virtuous behaviour; pen-ultimately, the challenges facing entrepreneurs in South Africa – overcoming the legacies of apartheid, containing crime, fostering an acceptable business ethic, and facilitating reconciliation between ethnic groups; and lastly, finding the power within – that illusive entrepreneurial spirit – self-reliance, looking beyond immediate obstacles, grasping opportunities, and understanding serendipity.
- Full Text:
- Date Issued: 2003
A proposed prioritization system for the management of invasive alien plants in South Africa
- Robertson, Mark P, Villet, Martin H, Fairbanks, Dean H K, Henderson, L, Higgins, Simon I, Hoffmann, John H, Le Maitre, David C, Palmer, Anthony R, Riggs, I, Shackleton, Charlie M, Zimmermann, Helmuth G
- Authors: Robertson, Mark P , Villet, Martin H , Fairbanks, Dean H K , Henderson, L , Higgins, Simon I , Hoffmann, John H , Le Maitre, David C , Palmer, Anthony R , Riggs, I , Shackleton, Charlie M , Zimmermann, Helmuth G
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6911 , http://hdl.handle.net/10962/d1011872
- Description: Every country has weed species whose presence conflicts in some way with human management objectives and needs. Resources for research and control are limited, so priority should be given to species that are the biggest problem. The prioritization system described in this article was designed to assess objectively research and control priorities of invasive alien plants at a national scale in South Africa. The evaluation consists of seventeen criteria, grouped into five modules, that assess invasiveness, spatial characteristics, potential impact, potential for control, and conflicts of interest for each plant species under consideration. Total prioritization scores, calculated from criterion and module scores, were used to assess a species' priority. Prioritization scores were calculated by combining independent assessments provided by several experts, thus increasing the reliability of the rankings. The total confidence score, a separate index, indicates the reliability and availability of data used to make an assessment. Candidate species for evaluation were identified and assessed by several experts using the prioritization system. The final ranking was made by combining two separate indices, the total prioritization score and the total confidence score. This approach integrates the plant's perceived priority with an index of data reliability. Of the 61 species assessed, those with the highest ranks (Lantana camara, Chromolaena odorata and Opuntia ficus-indica) had high prioritization and high confidence scores, and are thus of most concern. Those species with the lowest ranks, for example, Harrisia martinii, Opuntia spinulifera and Opuntia exaltata, had low prioritization scores and high confidence scores, and thus are of least concern. Our approach to ranking weeds offers several advantages over existing systems because it is designed for multiple assessors based on the Delphi decision-making technique, the criteria contribute equally to the total score, and the system can accommodate incomplete data on a species. Although the choice of criteria may be criticized and the system has certain limitations, it appears to have delivered credible results.
- Full Text:
- Date Issued: 2003
- Authors: Robertson, Mark P , Villet, Martin H , Fairbanks, Dean H K , Henderson, L , Higgins, Simon I , Hoffmann, John H , Le Maitre, David C , Palmer, Anthony R , Riggs, I , Shackleton, Charlie M , Zimmermann, Helmuth G
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6911 , http://hdl.handle.net/10962/d1011872
- Description: Every country has weed species whose presence conflicts in some way with human management objectives and needs. Resources for research and control are limited, so priority should be given to species that are the biggest problem. The prioritization system described in this article was designed to assess objectively research and control priorities of invasive alien plants at a national scale in South Africa. The evaluation consists of seventeen criteria, grouped into five modules, that assess invasiveness, spatial characteristics, potential impact, potential for control, and conflicts of interest for each plant species under consideration. Total prioritization scores, calculated from criterion and module scores, were used to assess a species' priority. Prioritization scores were calculated by combining independent assessments provided by several experts, thus increasing the reliability of the rankings. The total confidence score, a separate index, indicates the reliability and availability of data used to make an assessment. Candidate species for evaluation were identified and assessed by several experts using the prioritization system. The final ranking was made by combining two separate indices, the total prioritization score and the total confidence score. This approach integrates the plant's perceived priority with an index of data reliability. Of the 61 species assessed, those with the highest ranks (Lantana camara, Chromolaena odorata and Opuntia ficus-indica) had high prioritization and high confidence scores, and are thus of most concern. Those species with the lowest ranks, for example, Harrisia martinii, Opuntia spinulifera and Opuntia exaltata, had low prioritization scores and high confidence scores, and thus are of least concern. Our approach to ranking weeds offers several advantages over existing systems because it is designed for multiple assessors based on the Delphi decision-making technique, the criteria contribute equally to the total score, and the system can accommodate incomplete data on a species. Although the choice of criteria may be criticized and the system has certain limitations, it appears to have delivered credible results.
- Full Text:
- Date Issued: 2003
Action research case studies of participatory materials development in two community contexts in Zambia
- Authors: Lupele, Justin Kalaba
- Date: 2003
- Subjects: Community development -- Zambia -- Case studies Environmental education -- Zambia -- Case studies Sustainable development -- Zambia -- Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1417 , http://hdl.handle.net/10962/d1003298
- Description: This research reports on two action research case studies of participatory materials development in two rural community contexts in Zambia, namely Chiawa and Nalusanga. It aims to explore and articulate the relationships between community-based environmental education and participatory materials development in the WWF Zambia Education Project context; clarify participatory materials development processes by identifying the roles of different ‘actors’ in these processes and identify and analyse the contextual and other factors that may influence development and use of environmental education materials in rural communities. These aims were explored by means of a number of action research cycles of inquiry in the two communities. The study also articulates the significance of considering ambivalent globalising influences such as international conferences, debates, overseas development aid, national policies and how these shape and influence materials development work in a local context. In order to gain more insight into the local contexts, I developed contextual profiles on the two communities. These capture the contextual factors that influenced the participatory materials development processes. They include issues such as language, ethnicity, literacy, power relations and the local social economy, amongst others. Although this study has been predominately guided by the socially critical orientation to research and education, I have drawn on aspects of other research orientations. I have also explored some of the emerging critiques of the socially critical orientation. The findings of this study reveal the different roles participants can play in participatory materials development; participatory materials development processes as a learning process; the dynamics of participation in an African context; the role of language and literacy in materials development; the need for open-ended process models of learning amongst adult learners and the importance of merging expert and local knowledge in participatory materials development. This study opens up possibilities for further exploration of participatory materials development processes within the WWF ZEP context and beyond.
- Full Text:
- Date Issued: 2003
- Authors: Lupele, Justin Kalaba
- Date: 2003
- Subjects: Community development -- Zambia -- Case studies Environmental education -- Zambia -- Case studies Sustainable development -- Zambia -- Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1417 , http://hdl.handle.net/10962/d1003298
- Description: This research reports on two action research case studies of participatory materials development in two rural community contexts in Zambia, namely Chiawa and Nalusanga. It aims to explore and articulate the relationships between community-based environmental education and participatory materials development in the WWF Zambia Education Project context; clarify participatory materials development processes by identifying the roles of different ‘actors’ in these processes and identify and analyse the contextual and other factors that may influence development and use of environmental education materials in rural communities. These aims were explored by means of a number of action research cycles of inquiry in the two communities. The study also articulates the significance of considering ambivalent globalising influences such as international conferences, debates, overseas development aid, national policies and how these shape and influence materials development work in a local context. In order to gain more insight into the local contexts, I developed contextual profiles on the two communities. These capture the contextual factors that influenced the participatory materials development processes. They include issues such as language, ethnicity, literacy, power relations and the local social economy, amongst others. Although this study has been predominately guided by the socially critical orientation to research and education, I have drawn on aspects of other research orientations. I have also explored some of the emerging critiques of the socially critical orientation. The findings of this study reveal the different roles participants can play in participatory materials development; participatory materials development processes as a learning process; the dynamics of participation in an African context; the role of language and literacy in materials development; the need for open-ended process models of learning amongst adult learners and the importance of merging expert and local knowledge in participatory materials development. This study opens up possibilities for further exploration of participatory materials development processes within the WWF ZEP context and beyond.
- Full Text:
- Date Issued: 2003
An analysis of the potential for the marketing of ostrich meat in S.A
- Wessels, Philippus Lodewikus
- Authors: Wessels, Philippus Lodewikus
- Date: 2003
- Subjects: Ostriches -- South Africa , Ostrich products industry -- South Africa , Meat industry and trade -- South Africa , Marketing
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10930 , http://hdl.handle.net/10948/202 , Ostriches -- South Africa , Ostrich products industry -- South Africa , Meat industry and trade -- South Africa , Marketing
- Description: The research program addressed in this study was to do an analysis of the potentials of the marketing of ostrich meat in the South African market. Being the world leader in the ostrich industry, the research’s emphasis was to establish reasons why the meat industry does not explore the South African meat market. To achieve this object, a literature study to determine the key components of the current situation was undertaken and used as a theoretical model to analyse the current situation in the market as well as in the ostrich industry. In addition to the literature study, an empirical study was conducted to identify some critical issues that have an influence on the potential of the domestic market. The survey method used, based on the key components gained from the literature study, consisted of an in-depth scan of the macro-environment and thorough investigation of the target industry. The investigation involved using the Internet and World Wide Web, print media, personal interviews and telephonic interviews. The result of the literature study was finally combined with the results of the empirical study and some recommendations were made. The recommendations were applicable to the ostrich industry in so far that implementing some plans for the meat industry can have serious consequences for the other products of the ostrich industry
- Full Text:
- Date Issued: 2003
- Authors: Wessels, Philippus Lodewikus
- Date: 2003
- Subjects: Ostriches -- South Africa , Ostrich products industry -- South Africa , Meat industry and trade -- South Africa , Marketing
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10930 , http://hdl.handle.net/10948/202 , Ostriches -- South Africa , Ostrich products industry -- South Africa , Meat industry and trade -- South Africa , Marketing
- Description: The research program addressed in this study was to do an analysis of the potentials of the marketing of ostrich meat in the South African market. Being the world leader in the ostrich industry, the research’s emphasis was to establish reasons why the meat industry does not explore the South African meat market. To achieve this object, a literature study to determine the key components of the current situation was undertaken and used as a theoretical model to analyse the current situation in the market as well as in the ostrich industry. In addition to the literature study, an empirical study was conducted to identify some critical issues that have an influence on the potential of the domestic market. The survey method used, based on the key components gained from the literature study, consisted of an in-depth scan of the macro-environment and thorough investigation of the target industry. The investigation involved using the Internet and World Wide Web, print media, personal interviews and telephonic interviews. The result of the literature study was finally combined with the results of the empirical study and some recommendations were made. The recommendations were applicable to the ostrich industry in so far that implementing some plans for the meat industry can have serious consequences for the other products of the ostrich industry
- Full Text:
- Date Issued: 2003
An assessment of bait availability, utilization and management guidelines in Eastern Cape estuaries
- Authors: Jooste, Jakobus Gerrit
- Date: 2003
- Subjects: Upogebia african -- Effects of sediments on -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Fishing baits -- Conservation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11073 , http://hdl.handle.net/10948/334 , Upogebia african -- Effects of sediments on -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Fishing baits -- Conservation -- South Africa -- Eastern Cape
- Description: Aspects around the management of benthic soft sediment bait organisms, with special focus on the mud prawn (Upogebia africana) of eastern Cape estuaries was investigated. The recreational linefishery of the Gamtoos estuary was described, and compared to previous studies. Target fish species was identified, and a large dependency on bait sourced from estuaries needed for the capture of these species was noted, especially for spotted grunter (Pomadasys commersonnii). A comparison between bait use, success and the natural diet of target fish species was also made. The structure and distribution of sediments in the old channel mud banks was described and compared with historical data. The influence of sediments on mud prawn distribution was investigated, but no significant interactions were found at the study site. The impacts of once-off pumping and digging events, and monthly trampling on the sediments and mud prawn population was studied over a 7-month period. Initial removal rates as well as recovery time varied significantly between the two collection methods, while the largest decline in prawn numbers (to zero) with no recovery visible after seven months was caused by trampling. All disturbances caused some alteration in sediment composition, but not to such an extent that the sediments became unfavorable for mud prawns. Trampling did, however, result in the compaction of sediments to such a degree that prawns could not construct burrows. Issues around current removal quotas of bait species as well as the creation of a small-scale commercial (SSC) bait selling operation at Swartkops estuary were critically evaluated, and suggestions for the future removal rates of mud prawns based on production export calculations were made. The distribution, size, sex ratios and number of gravid females occurring along a tidal gradient as well as along horizontal gradient of the mud bank during growth (January – March) and reproductive (September – October) periods was investigated. Changes in the distribution of females between the two study periods were significant, while the distribution of reproductively active females were closely linked to the low water mark (Lower tidal levels). Females occurring in this zone were also significantly larger than females occurring towards the back of the study site. Some minor changes along the horizontal gradient were also observed. The sediment compos ition of the mud bank was found not to play a role in this distribution, leading to the suggestion that exposure to ebb and flood tide currents could influence female prawn distributions. Management recommendations based on these observations were made.
- Full Text:
- Date Issued: 2003
- Authors: Jooste, Jakobus Gerrit
- Date: 2003
- Subjects: Upogebia african -- Effects of sediments on -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Fishing baits -- Conservation -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11073 , http://hdl.handle.net/10948/334 , Upogebia african -- Effects of sediments on -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Fishing baits -- Conservation -- South Africa -- Eastern Cape
- Description: Aspects around the management of benthic soft sediment bait organisms, with special focus on the mud prawn (Upogebia africana) of eastern Cape estuaries was investigated. The recreational linefishery of the Gamtoos estuary was described, and compared to previous studies. Target fish species was identified, and a large dependency on bait sourced from estuaries needed for the capture of these species was noted, especially for spotted grunter (Pomadasys commersonnii). A comparison between bait use, success and the natural diet of target fish species was also made. The structure and distribution of sediments in the old channel mud banks was described and compared with historical data. The influence of sediments on mud prawn distribution was investigated, but no significant interactions were found at the study site. The impacts of once-off pumping and digging events, and monthly trampling on the sediments and mud prawn population was studied over a 7-month period. Initial removal rates as well as recovery time varied significantly between the two collection methods, while the largest decline in prawn numbers (to zero) with no recovery visible after seven months was caused by trampling. All disturbances caused some alteration in sediment composition, but not to such an extent that the sediments became unfavorable for mud prawns. Trampling did, however, result in the compaction of sediments to such a degree that prawns could not construct burrows. Issues around current removal quotas of bait species as well as the creation of a small-scale commercial (SSC) bait selling operation at Swartkops estuary were critically evaluated, and suggestions for the future removal rates of mud prawns based on production export calculations were made. The distribution, size, sex ratios and number of gravid females occurring along a tidal gradient as well as along horizontal gradient of the mud bank during growth (January – March) and reproductive (September – October) periods was investigated. Changes in the distribution of females between the two study periods were significant, while the distribution of reproductively active females were closely linked to the low water mark (Lower tidal levels). Females occurring in this zone were also significantly larger than females occurring towards the back of the study site. Some minor changes along the horizontal gradient were also observed. The sediment compos ition of the mud bank was found not to play a role in this distribution, leading to the suggestion that exposure to ebb and flood tide currents could influence female prawn distributions. Management recommendations based on these observations were made.
- Full Text:
- Date Issued: 2003
An assessment of selected non-water benefits of the Working for Water Programme in the Eastern and Southern Cape
- Authors: Du Plessis, Lily Lozelle
- Date: 2003
- Subjects: Water resources development -- South Africa -- Eastern Cape -- Cost effectiveness , Water resources development -- South Africa -- Southern Cape -- Cost effectiveness , Water conservation projects -- South Africa -- Eastern Cape -- Cost effectiveness , Water conservation projects -- South Africa -- Southern Cape -- Cost effectiveness , Land use -- Economic aspects -- South Africa -- Eastern Cape , Land use -- Economic aspects -- South Africa -- Southern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10991 , http://hdl.handle.net/10948/340 , Water resources development -- South Africa -- Eastern Cape -- Cost effectiveness , Water resources development -- South Africa -- Southern Cape -- Cost effectiveness , Water conservation projects -- South Africa -- Eastern Cape -- Cost effectiveness , Water conservation projects -- South Africa -- Southern Cape -- Cost effectiveness , Land use -- Economic aspects -- South Africa -- Eastern Cape , Land use -- Economic aspects -- South Africa -- Southern Cape
- Description: 1.1 Background to, and motivation for, the study: The Working for Water programme (WfW) is a public works programme designed to clear South Africa of water-consuming invasive alien tree and plants, and to replace them with low water consuming indigenous species. This would prevent a loss of more than 4000 million cubic metres water per annum from the hydrological cycle (DWAF, 1998). The economic viability of the programme has been established in the Western Cape and Kwazulu-Natal (van Wilgen, Little, Chapman, Görgens, Willems and Marais, 1997; Gilham and Haynes, 2001), but questioned in the Eastern and Southern Cape (Hosking, du Preez, Campbell, Wooldridge and du Plessis, 2002). Hosking et al. (2002) investigated the economic case for the programme by performing a Cost Benefit Analysis (CBA), based on increased water yield and livestock potential, on six selected sites in the Eastern and Southern Cape, viz. Albany, Kat River, Pot River, Tsitsikamma, Kouga and Port Elizabeth Driftsands.
- Full Text:
- Date Issued: 2003
- Authors: Du Plessis, Lily Lozelle
- Date: 2003
- Subjects: Water resources development -- South Africa -- Eastern Cape -- Cost effectiveness , Water resources development -- South Africa -- Southern Cape -- Cost effectiveness , Water conservation projects -- South Africa -- Eastern Cape -- Cost effectiveness , Water conservation projects -- South Africa -- Southern Cape -- Cost effectiveness , Land use -- Economic aspects -- South Africa -- Eastern Cape , Land use -- Economic aspects -- South Africa -- Southern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:10991 , http://hdl.handle.net/10948/340 , Water resources development -- South Africa -- Eastern Cape -- Cost effectiveness , Water resources development -- South Africa -- Southern Cape -- Cost effectiveness , Water conservation projects -- South Africa -- Eastern Cape -- Cost effectiveness , Water conservation projects -- South Africa -- Southern Cape -- Cost effectiveness , Land use -- Economic aspects -- South Africa -- Eastern Cape , Land use -- Economic aspects -- South Africa -- Southern Cape
- Description: 1.1 Background to, and motivation for, the study: The Working for Water programme (WfW) is a public works programme designed to clear South Africa of water-consuming invasive alien tree and plants, and to replace them with low water consuming indigenous species. This would prevent a loss of more than 4000 million cubic metres water per annum from the hydrological cycle (DWAF, 1998). The economic viability of the programme has been established in the Western Cape and Kwazulu-Natal (van Wilgen, Little, Chapman, Görgens, Willems and Marais, 1997; Gilham and Haynes, 2001), but questioned in the Eastern and Southern Cape (Hosking, du Preez, Campbell, Wooldridge and du Plessis, 2002). Hosking et al. (2002) investigated the economic case for the programme by performing a Cost Benefit Analysis (CBA), based on increased water yield and livestock potential, on six selected sites in the Eastern and Southern Cape, viz. Albany, Kat River, Pot River, Tsitsikamma, Kouga and Port Elizabeth Driftsands.
- Full Text:
- Date Issued: 2003
An investigation into the current and potential benefits of tourism-based development in the Albany and Peddie districts
- Authors: Klinkradt, Mary Louise
- Date: 2003 , 2013-05-27
- Subjects: Tourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Grahamstown , Tourism -- South Africa -- Peddie , Ecotourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Eastern Cape -- Management , Tourism -- Social aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:4811 , http://hdl.handle.net/10962/d1004904 , Tourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Grahamstown , Tourism -- South Africa -- Peddie , Ecotourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Eastern Cape -- Management , Tourism -- Social aspects -- South Africa -- Eastern Cape
- Description: This research considers the relationship between tourism and development, and how tourism can be used as a means of promoting development. In order to explore this relationship, two districts in the Eastern Cape province of South Africa, the Albany and Peddie Districts have been selected as case study areas. Both the Albany and Peddie Districts are in need of development which can meet the economic and social development of the districts. One such option for the two districts is tourism-based development. This research examines the current status of tourism in both districts through the use of secondary data analysis and primary data gathered from questionnaires and interviews undertaken with tourists and representatives of key stakeholders in the tourism industry. This data was used to establish the current and future potential of tourism in the districts in terms of the availability and diversity of attractions and the tourism assets and facilities in the districts. It was also used to determine whether or not tourism, by promoting infrastructural and economic development, may lead to the socio-economic upliftment of the Albany and Peddie Districts. The results obtained from this research highlight the significant lack of tourism infrastructure in the Peddie District, and the reality that the tourism potential of the district remains untapped. With the marketing and promotion of tourism to the district, and the associated tourist requirements such as accommodation, and other facilities, tourism does hold a potential key to the socio-economic development of the district. The Albany District, however, has a well-established tourism industry, but the development spin-ofts are minimal, and the potential for further tourism-based development in the future would therefore appear to be somewhat limited. A GIS (Geographic Information System) was use to determine and detail possible tourism routes, a final outcome of the investigation being the proposal of two tourism routes to draw people into and through the study area, based on the current assets and attractions of the two districts. These routes highlight one of the options available in the districts to promote much needed development in the two districts through the use of the tourism industry. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2003
- Authors: Klinkradt, Mary Louise
- Date: 2003 , 2013-05-27
- Subjects: Tourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Grahamstown , Tourism -- South Africa -- Peddie , Ecotourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Eastern Cape -- Management , Tourism -- Social aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:4811 , http://hdl.handle.net/10962/d1004904 , Tourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Grahamstown , Tourism -- South Africa -- Peddie , Ecotourism -- South Africa -- Eastern Cape , Tourism -- South Africa -- Eastern Cape -- Management , Tourism -- Social aspects -- South Africa -- Eastern Cape
- Description: This research considers the relationship between tourism and development, and how tourism can be used as a means of promoting development. In order to explore this relationship, two districts in the Eastern Cape province of South Africa, the Albany and Peddie Districts have been selected as case study areas. Both the Albany and Peddie Districts are in need of development which can meet the economic and social development of the districts. One such option for the two districts is tourism-based development. This research examines the current status of tourism in both districts through the use of secondary data analysis and primary data gathered from questionnaires and interviews undertaken with tourists and representatives of key stakeholders in the tourism industry. This data was used to establish the current and future potential of tourism in the districts in terms of the availability and diversity of attractions and the tourism assets and facilities in the districts. It was also used to determine whether or not tourism, by promoting infrastructural and economic development, may lead to the socio-economic upliftment of the Albany and Peddie Districts. The results obtained from this research highlight the significant lack of tourism infrastructure in the Peddie District, and the reality that the tourism potential of the district remains untapped. With the marketing and promotion of tourism to the district, and the associated tourist requirements such as accommodation, and other facilities, tourism does hold a potential key to the socio-economic development of the district. The Albany District, however, has a well-established tourism industry, but the development spin-ofts are minimal, and the potential for further tourism-based development in the future would therefore appear to be somewhat limited. A GIS (Geographic Information System) was use to determine and detail possible tourism routes, a final outcome of the investigation being the proposal of two tourism routes to draw people into and through the study area, based on the current assets and attractions of the two districts. These routes highlight one of the options available in the districts to promote much needed development in the two districts through the use of the tourism industry. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2003
An investigation into the neuroprotective properties of curcumin
- Authors: Daniel, Sheril
- Date: 2003
- Subjects: Turmeric -- Therapeutic use , Nervous system -- Degeneration -- Prevention
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3753 , http://hdl.handle.net/10962/d1003231 , Turmeric -- Therapeutic use , Nervous system -- Degeneration -- Prevention
- Description: An increasing number of studies show that nutritional antioxidants such as vitamin E and polyphenols are capable of blocking neuronal death in vitro and may have therapeutic properties in animal models of neurodegenerative diseases including Alzheimer’s and Parkinson’s diseases. In the present study, the neuroprotective ability of one such polyphenolic antioxidant, curcumin, was investigated. Curcumin is the yellow curry spice derived from turmeric, and is widely used as a dietary component and herbal medicine in India. Most neurological disorders are postulated to have an oxidative or excitototoxic basis. Thus the effects of curcumin on oxidative stress in the rat brain were investigated. Curcumin, administered to the rat in vivo and in vitro, was able to exert protective effects on oxidative damage in the brain, induced by cyanide, a mitochondrial inhibitor. Curcumin also offered protection against quinolinic acid induced lipid peroxidation, and this protection was extended to lipid peroxidation induced by metals such as lead and cadmium in the rat brain. Experiments conducted on the pineal gland revealed an increased production of the neuroprotective hormone melatonin in presence of curcumin in vivo. The hippocampus is functionally related to vital behaviour and intellectual activities and is known to be a primary target for neuronal degeneration in the brains of patients with Alzheimer’s disease. Histological studies were undertaken to assess the effects of curcumin on lead induced toxicity on the rat hippocampus, the results of which show that curcumin affords significant protection to the hippocampus of the lead treated rats. This study also sought to elucidate possible mechanisms by which curcumin exerts its neuroprotective capabilities. Curcumin was found to inhibit the action of cyanide on the mitochondrial electron transport chain, one of the most common sources of free radicals. Electrochemical, UV/VIS and Infrared spectroscopy were used to characterise interactions between curcumin and the metals lead, cadmium, iron (II) and iron (III). Curcumin was shown to directly chelate these metals with the formation and isolation of two new curcumin complexes with lead, and one complex each with cadmium and iron (III). These results suggest chelation of toxic metals as a mechanism of neuroprotection afforded by curcumin. The need for neuroprotective agents is urgent considering the rapid rise in the elderly population and the proportionate increase in neurological disorders. The findings of this study indicate that curcumin, a well-established dietary antioxidant, is capable of playing a bigger role in neuroprotection, which needs to be further explored and exploited.
- Full Text:
- Date Issued: 2003
- Authors: Daniel, Sheril
- Date: 2003
- Subjects: Turmeric -- Therapeutic use , Nervous system -- Degeneration -- Prevention
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3753 , http://hdl.handle.net/10962/d1003231 , Turmeric -- Therapeutic use , Nervous system -- Degeneration -- Prevention
- Description: An increasing number of studies show that nutritional antioxidants such as vitamin E and polyphenols are capable of blocking neuronal death in vitro and may have therapeutic properties in animal models of neurodegenerative diseases including Alzheimer’s and Parkinson’s diseases. In the present study, the neuroprotective ability of one such polyphenolic antioxidant, curcumin, was investigated. Curcumin is the yellow curry spice derived from turmeric, and is widely used as a dietary component and herbal medicine in India. Most neurological disorders are postulated to have an oxidative or excitototoxic basis. Thus the effects of curcumin on oxidative stress in the rat brain were investigated. Curcumin, administered to the rat in vivo and in vitro, was able to exert protective effects on oxidative damage in the brain, induced by cyanide, a mitochondrial inhibitor. Curcumin also offered protection against quinolinic acid induced lipid peroxidation, and this protection was extended to lipid peroxidation induced by metals such as lead and cadmium in the rat brain. Experiments conducted on the pineal gland revealed an increased production of the neuroprotective hormone melatonin in presence of curcumin in vivo. The hippocampus is functionally related to vital behaviour and intellectual activities and is known to be a primary target for neuronal degeneration in the brains of patients with Alzheimer’s disease. Histological studies were undertaken to assess the effects of curcumin on lead induced toxicity on the rat hippocampus, the results of which show that curcumin affords significant protection to the hippocampus of the lead treated rats. This study also sought to elucidate possible mechanisms by which curcumin exerts its neuroprotective capabilities. Curcumin was found to inhibit the action of cyanide on the mitochondrial electron transport chain, one of the most common sources of free radicals. Electrochemical, UV/VIS and Infrared spectroscopy were used to characterise interactions between curcumin and the metals lead, cadmium, iron (II) and iron (III). Curcumin was shown to directly chelate these metals with the formation and isolation of two new curcumin complexes with lead, and one complex each with cadmium and iron (III). These results suggest chelation of toxic metals as a mechanism of neuroprotection afforded by curcumin. The need for neuroprotective agents is urgent considering the rapid rise in the elderly population and the proportionate increase in neurological disorders. The findings of this study indicate that curcumin, a well-established dietary antioxidant, is capable of playing a bigger role in neuroprotection, which needs to be further explored and exploited.
- Full Text:
- Date Issued: 2003
An investigation into the physico-chemical and neuroprotective properties of melatonin and 6-hydroxymelatonin
- Authors: Maharaj, Deepa Sukhdev
- Date: 2003
- Subjects: Melatonin Nervous system -- Degeneration -- Treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3768 , http://hdl.handle.net/10962/d1003246
- Description: Until the beginning of this decade the antioxidant, melatonin, had been considered as little more than a tranquilizing hormone, responsible for regulating certain circadian and circannual rhythms. However, it is the discovery of melatonin as a free radical scavenger that has generated the most interest in recent years. The reduction of melatonin with age has been associated with neurodegenerative diseases such as Alzheimer’s disease (AD)and therefore, melatonin has been implicated to have an important clinical role in neuroprotection. Thus, for several years melatonin has attracted increasing attention from the general press with many advertisements touting this indoleamine to act as an aphrodisiac, rejuvenator, protector against diseases and a general wonder drug. However, melatonin formulations appear with no labelling for the correct storage conditions, dosage and side effects, as well as no control for purity and self-medicating with an unregulated product. In addition, there is much controversy surrounding the antioxidative properties of the indolemaine, 6-hydroxymelatonin (6-OHM). Therefore, the first part of this study aims to elucidate the physico-chemical and various stability characteristics of the pineal antioxidant, melatonin, while the second part is devoted to investigating the neuroprotective properties of the primary hepatic metabolite of melatonin, 6-OHM. The physical properties of melatonin were determined using various chemical techniques. This information served to both characterize and confirm the identity of melatonin raw material used in this study. In addition, this information serves to be essential as the physical properties of melatonin have not been reported in detail in literature, to date. Thereafter, using a validated high performance liquid chromatography (HPLC) method, the various physico-chemical and stability characteristics of melatonin were determined. Melatonin was shown to be extremely lipophilic, while the hygroscopic study indicates that melatonin raw material is extremely hygroscopic at temperatures above 40°C, whereas melatonin tablets are hygroscopic when left out of the original container. This study highlights the need for consumers to be aware of the proper storage of melatonin tablets to improve the stability and ensure long term integrity of the compound. Since, melatonin is most often administered orally, thus exposing it to a large variations in pH, within the gastrointestinal tract, it was decided to investigate the stability of melatonin over a range of pH’s and temperatures. The findings imply that melatonin is relatively stable at body temperature when ingested orally and that orally administered slow release preparations of melatonin should be relatively stable and therefore exhibit favourable bioavailability. However melatonin was shown to be unstable in solution. This provides important information and a challenge to the formulators of this drug substance in a liquid dosage form. An assessment of the photostability of melatonin dosage forms using International Committee on Harmonization (ICH) conditions revealed melatonin to be light sensitive and thus indicates a need for careful consideration of the packaging of these drug products. In addition a detailed assessment of the photochemistry and photoproducts formed during the UV photodegradation of melatonin is reported. Melatonin is shown to rapidly degrade in the presence of UV light, with the presence of oxygen accelerating the photodegradation. N1-acetyl-N2-formyl-5-methoxykynurenamine(AFMK) and 6-OHM were identified as the major photoproducts formed and these agents have been shown previously to retain antioxidant activity. One of the concerns of using melatonin in sunscreens is its photostability. However, it is reported in this study that the degraded solution of melatonin still possesses equipotent free radical scavenging ability as melatonin, despite the absence of melatonin in solution. In addition, melatonin is shown to reduce UV-induced oxidative stress in rat skin homogenate. Thus, these results make melatonin a likely candidate for inclusion in sunscreen preparations. Neuronal damage due to oxidative stress has been implicated in several neurodegenerative disorders. 6-OHM is not only formed as the major hepatic metabolite of melatonin, but also when melatonin reacts with toxic radicals as well as UV light. Thus the second part of the study aims to elucidate and further characterize the mechanism behind 6-OHM’s neuroprotection. The results show 6-OHM to be a more potent singlet oxygen and superoxide anion scavenger than melatonin. In addition, the results show 6-OHM to offer protection against, oxidative stress and lipid peroxidation induced by several neurotoxins in the rat brain and hippocampus. The hippocampus is an important region of the brain responsible for the formation of memory and any agent that induces stress in this area has detrimental effects and could lead to various types of dementia. Such agents include quinolinic acid (QA) and iron (II). Histological studies undertaken reveal that 6-OHM is able to protect hippocampal neurons against QA and iron (II) induced necrotic cell death. Immunohistochemical investigations showed that QA moderately induces apoptotic cell death in the hippocampus which is inhibited by both melatonin and 6-OHM. The study sought to elucidate possible mechanisms by which 6-OHM exerts its neuroprotective capabilities and the results show 6-OHM to inhibit the action of cyanide on the mitochondrial electron transport chain (ETC), one of the most common sources of free radicals. In addition, 6-OHM treatment alone, increased ETC activity above basal control levels and the results show 6-OHM to increase complex I activity in the mitochondrial ETC. Electrochemical, ultraviolet/visible spectroscopy (UV/Vis) and HPLC assessment show that an interaction exists between 6-OHM and iron (III) and 6-OHM is able to reduce iron (III) to a more biologically usable form viz. iron (II) which can be incorporated into important biomolecules such as heme. One dire consequence of this interaction is the ready provision of iron (II) to drive the Fenton reaction. However the biological and histological assessments show 6-OHM to prevent iron (II)-induced lipid peroxidation and necrotic cell death and thus, provide evidence of its antioxidant properties. The results also show 6-OHM to promote Hsp70 induction in the hippocampus. Heat shock proteins, especially Hsp 70 plays a role in cytoprotection by capturing denatured proteins and facilitating the refolding of these proteins once the stress has been relieved. 6-OHM treatment alone and together with QA was shown to increase the level of expression of Hsp70, both inducible and cognate forms of the protein. This suggests that 6-OHM helps to protect against cellular protein damage induced by any form of stress the cell may encounter. Melatonin treatment alone and in combination with QA was shown to prevent increases in the level of Hsp70 in the hippocampus, indicating that melatonin was able to reduce oxidative stress induced by QA such that Hsp70 expression was not required. The discovery of neuroprotective agents, such as melatonin and 6-OHM, is becoming important considering the rapid rise in the elderly population and the proportionate increase in neurological disorders. The findings of this study indicate the need for important information regarding the correct storage conditions and stability characteristics of melatonin dosage forms. In addition, the results indicate that 6-OHM has a definite role to play as an antioxidant. Thus further research may favour the use of these agents in the treatment of several neurodegenerative disorders.
- Full Text:
- Date Issued: 2003
- Authors: Maharaj, Deepa Sukhdev
- Date: 2003
- Subjects: Melatonin Nervous system -- Degeneration -- Treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3768 , http://hdl.handle.net/10962/d1003246
- Description: Until the beginning of this decade the antioxidant, melatonin, had been considered as little more than a tranquilizing hormone, responsible for regulating certain circadian and circannual rhythms. However, it is the discovery of melatonin as a free radical scavenger that has generated the most interest in recent years. The reduction of melatonin with age has been associated with neurodegenerative diseases such as Alzheimer’s disease (AD)and therefore, melatonin has been implicated to have an important clinical role in neuroprotection. Thus, for several years melatonin has attracted increasing attention from the general press with many advertisements touting this indoleamine to act as an aphrodisiac, rejuvenator, protector against diseases and a general wonder drug. However, melatonin formulations appear with no labelling for the correct storage conditions, dosage and side effects, as well as no control for purity and self-medicating with an unregulated product. In addition, there is much controversy surrounding the antioxidative properties of the indolemaine, 6-hydroxymelatonin (6-OHM). Therefore, the first part of this study aims to elucidate the physico-chemical and various stability characteristics of the pineal antioxidant, melatonin, while the second part is devoted to investigating the neuroprotective properties of the primary hepatic metabolite of melatonin, 6-OHM. The physical properties of melatonin were determined using various chemical techniques. This information served to both characterize and confirm the identity of melatonin raw material used in this study. In addition, this information serves to be essential as the physical properties of melatonin have not been reported in detail in literature, to date. Thereafter, using a validated high performance liquid chromatography (HPLC) method, the various physico-chemical and stability characteristics of melatonin were determined. Melatonin was shown to be extremely lipophilic, while the hygroscopic study indicates that melatonin raw material is extremely hygroscopic at temperatures above 40°C, whereas melatonin tablets are hygroscopic when left out of the original container. This study highlights the need for consumers to be aware of the proper storage of melatonin tablets to improve the stability and ensure long term integrity of the compound. Since, melatonin is most often administered orally, thus exposing it to a large variations in pH, within the gastrointestinal tract, it was decided to investigate the stability of melatonin over a range of pH’s and temperatures. The findings imply that melatonin is relatively stable at body temperature when ingested orally and that orally administered slow release preparations of melatonin should be relatively stable and therefore exhibit favourable bioavailability. However melatonin was shown to be unstable in solution. This provides important information and a challenge to the formulators of this drug substance in a liquid dosage form. An assessment of the photostability of melatonin dosage forms using International Committee on Harmonization (ICH) conditions revealed melatonin to be light sensitive and thus indicates a need for careful consideration of the packaging of these drug products. In addition a detailed assessment of the photochemistry and photoproducts formed during the UV photodegradation of melatonin is reported. Melatonin is shown to rapidly degrade in the presence of UV light, with the presence of oxygen accelerating the photodegradation. N1-acetyl-N2-formyl-5-methoxykynurenamine(AFMK) and 6-OHM were identified as the major photoproducts formed and these agents have been shown previously to retain antioxidant activity. One of the concerns of using melatonin in sunscreens is its photostability. However, it is reported in this study that the degraded solution of melatonin still possesses equipotent free radical scavenging ability as melatonin, despite the absence of melatonin in solution. In addition, melatonin is shown to reduce UV-induced oxidative stress in rat skin homogenate. Thus, these results make melatonin a likely candidate for inclusion in sunscreen preparations. Neuronal damage due to oxidative stress has been implicated in several neurodegenerative disorders. 6-OHM is not only formed as the major hepatic metabolite of melatonin, but also when melatonin reacts with toxic radicals as well as UV light. Thus the second part of the study aims to elucidate and further characterize the mechanism behind 6-OHM’s neuroprotection. The results show 6-OHM to be a more potent singlet oxygen and superoxide anion scavenger than melatonin. In addition, the results show 6-OHM to offer protection against, oxidative stress and lipid peroxidation induced by several neurotoxins in the rat brain and hippocampus. The hippocampus is an important region of the brain responsible for the formation of memory and any agent that induces stress in this area has detrimental effects and could lead to various types of dementia. Such agents include quinolinic acid (QA) and iron (II). Histological studies undertaken reveal that 6-OHM is able to protect hippocampal neurons against QA and iron (II) induced necrotic cell death. Immunohistochemical investigations showed that QA moderately induces apoptotic cell death in the hippocampus which is inhibited by both melatonin and 6-OHM. The study sought to elucidate possible mechanisms by which 6-OHM exerts its neuroprotective capabilities and the results show 6-OHM to inhibit the action of cyanide on the mitochondrial electron transport chain (ETC), one of the most common sources of free radicals. In addition, 6-OHM treatment alone, increased ETC activity above basal control levels and the results show 6-OHM to increase complex I activity in the mitochondrial ETC. Electrochemical, ultraviolet/visible spectroscopy (UV/Vis) and HPLC assessment show that an interaction exists between 6-OHM and iron (III) and 6-OHM is able to reduce iron (III) to a more biologically usable form viz. iron (II) which can be incorporated into important biomolecules such as heme. One dire consequence of this interaction is the ready provision of iron (II) to drive the Fenton reaction. However the biological and histological assessments show 6-OHM to prevent iron (II)-induced lipid peroxidation and necrotic cell death and thus, provide evidence of its antioxidant properties. The results also show 6-OHM to promote Hsp70 induction in the hippocampus. Heat shock proteins, especially Hsp 70 plays a role in cytoprotection by capturing denatured proteins and facilitating the refolding of these proteins once the stress has been relieved. 6-OHM treatment alone and together with QA was shown to increase the level of expression of Hsp70, both inducible and cognate forms of the protein. This suggests that 6-OHM helps to protect against cellular protein damage induced by any form of stress the cell may encounter. Melatonin treatment alone and in combination with QA was shown to prevent increases in the level of Hsp70 in the hippocampus, indicating that melatonin was able to reduce oxidative stress induced by QA such that Hsp70 expression was not required. The discovery of neuroprotective agents, such as melatonin and 6-OHM, is becoming important considering the rapid rise in the elderly population and the proportionate increase in neurological disorders. The findings of this study indicate the need for important information regarding the correct storage conditions and stability characteristics of melatonin dosage forms. In addition, the results indicate that 6-OHM has a definite role to play as an antioxidant. Thus further research may favour the use of these agents in the treatment of several neurodegenerative disorders.
- Full Text:
- Date Issued: 2003
An object relational psychoanalysis of selected Tennessee Williams play texts
- Authors: Tosio, Paul
- Date: 2003
- Subjects: Williams, Tennessee, 1911-1983 Williams, Tennessee, 1911-1983 -- Knowledge -- Psychology Object relations (Psychoanalysis) Psychoanalysis Drama -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2150 , http://hdl.handle.net/10962/d1002382
- Description: Tennessee Williams is a playwright of great psychological depth. This thesis probes some of the complexities of his work through the use of Object Relational Psychoanalysis, specifically employing the theories of Melanie Klein, W.R.D. Fairbairn and Donald Winnicott. The Glass Menagerie, A Streetcar Named Desire, Cat On A Hot Tin Roof and The Night of The Iguana are analysed from this theoretical stance. All of these plays display great perceptiveness into the human condition, accurately portraying many psychological relational themes. Certain Object Relational themes become very apparent in these analyses. These themes include, Dependency (especially in The Glass Menagerie), Reparation (particularly in A Streetcar Named Desire), Falsehood (notably in Cat on a Hot Tin Roof), Idealisation (evident in The Night of The Iguana), Honest Empathetic Relations (apparent in Cat on a Hot Tin Roof and The Night of The Iguana) as well as Guilt, Object Loss, Sexual Guilt, and Obligation (recurring throughout these plays). It is advanced that Williams’ plays posses an honest and insightful understanding of human relations and, as such, are of contemporary value. This Thesis is not only an academic study, but also has practical applications for dramatists. With an increased understanding of the intrinsic tensions and motivations within such plays, offered by such psychoanalytic strategy, performance and staging of such work may be enhanced valuably.
- Full Text:
- Date Issued: 2003
- Authors: Tosio, Paul
- Date: 2003
- Subjects: Williams, Tennessee, 1911-1983 Williams, Tennessee, 1911-1983 -- Knowledge -- Psychology Object relations (Psychoanalysis) Psychoanalysis Drama -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2150 , http://hdl.handle.net/10962/d1002382
- Description: Tennessee Williams is a playwright of great psychological depth. This thesis probes some of the complexities of his work through the use of Object Relational Psychoanalysis, specifically employing the theories of Melanie Klein, W.R.D. Fairbairn and Donald Winnicott. The Glass Menagerie, A Streetcar Named Desire, Cat On A Hot Tin Roof and The Night of The Iguana are analysed from this theoretical stance. All of these plays display great perceptiveness into the human condition, accurately portraying many psychological relational themes. Certain Object Relational themes become very apparent in these analyses. These themes include, Dependency (especially in The Glass Menagerie), Reparation (particularly in A Streetcar Named Desire), Falsehood (notably in Cat on a Hot Tin Roof), Idealisation (evident in The Night of The Iguana), Honest Empathetic Relations (apparent in Cat on a Hot Tin Roof and The Night of The Iguana) as well as Guilt, Object Loss, Sexual Guilt, and Obligation (recurring throughout these plays). It is advanced that Williams’ plays posses an honest and insightful understanding of human relations and, as such, are of contemporary value. This Thesis is not only an academic study, but also has practical applications for dramatists. With an increased understanding of the intrinsic tensions and motivations within such plays, offered by such psychoanalytic strategy, performance and staging of such work may be enhanced valuably.
- Full Text:
- Date Issued: 2003
Applied studies of some Southern African blowflies (Diptera: Calliphoridae) of forensic importance
- Authors: Lunt, Nicola
- Date: 2003
- Subjects: Diptera -- South Africa , Blowflies -- South Africa , Forensic entomology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5803 , http://hdl.handle.net/10962/d1006202 , Diptera -- South Africa , Blowflies -- South Africa , Forensic entomology
- Description: Three major aspects of blowfly (Diptera: Calliphoridae) research were the focus of this study. Firstly, the phylogenetic relationships of 40 oestroid species from a variety of geographical localities were investigated using Cytochrome Oxidase b subunit I (COl) gene sequences. Maximum parsimony (MP) and Jukes-Cantor neighbor-joining (NJ) analyses both extracted a paraphyletic Calliphoridae, with the Calliphorinae-Luciliinae clade being sister to the Sarcophagidae. Short branch lengths within Chrysomya indicate a recent rapid radiation of this genus. Phormia and Protophormia either formed a sister clade to Chrysomya, or were embedded in this genus. Tree topologies were comparable between MP and NJ trees, but the positions of some genera were ambiguous. Secondly, developmental parameters and behaviour were investigated for four southern African species of forensically important blowflies viz. Chrysomya chloropyga, C. putoria, C. megacephala and Lucilia sericata, and ad hoc observations were made for Calliphora croceipalpis, Chrysomya marginalis and the predatory C. albiceps. Choice of oviposition substrate differed between species, mirroring substrate preferences in the field. Sexual dimorphism and dwarfism within a cohort complicated ageing maggots using size, but the use of developmental events (e.g. ecdysis) allowed ages to be determined unambiguously. Separate species status was supported for the previously synonymised C. chloropyga and C. putoria, by differences in maggot behaviour, larval growth rates and temperature optima. The proportion of total development time assigned to each larval instar and pupariation was variable among temperatures, but similar between congeneric species. Thirdly, since a negative linear relationship was found to occur between the developmental constant (K) and developmental zero (D₀) for both Calliphoridae and Sarcophagidae, the potential for predicting physiological parameters of unstudied taxa was investigated. Species and genera of Palaearctic origin generally had high K's and low D₀'s, and the reverse was true for the tropical taxa. It was found that both K and D₀ can be estimated for "unknown" taxa using the Felsenstein's Independent Contrasts (FIC) method of PDTree (Garland et al. 200 I), provided that branch lengths are relatively short and the phylogenetic position of the estimated taxon is unambiguous.
- Full Text:
- Date Issued: 2003
- Authors: Lunt, Nicola
- Date: 2003
- Subjects: Diptera -- South Africa , Blowflies -- South Africa , Forensic entomology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5803 , http://hdl.handle.net/10962/d1006202 , Diptera -- South Africa , Blowflies -- South Africa , Forensic entomology
- Description: Three major aspects of blowfly (Diptera: Calliphoridae) research were the focus of this study. Firstly, the phylogenetic relationships of 40 oestroid species from a variety of geographical localities were investigated using Cytochrome Oxidase b subunit I (COl) gene sequences. Maximum parsimony (MP) and Jukes-Cantor neighbor-joining (NJ) analyses both extracted a paraphyletic Calliphoridae, with the Calliphorinae-Luciliinae clade being sister to the Sarcophagidae. Short branch lengths within Chrysomya indicate a recent rapid radiation of this genus. Phormia and Protophormia either formed a sister clade to Chrysomya, or were embedded in this genus. Tree topologies were comparable between MP and NJ trees, but the positions of some genera were ambiguous. Secondly, developmental parameters and behaviour were investigated for four southern African species of forensically important blowflies viz. Chrysomya chloropyga, C. putoria, C. megacephala and Lucilia sericata, and ad hoc observations were made for Calliphora croceipalpis, Chrysomya marginalis and the predatory C. albiceps. Choice of oviposition substrate differed between species, mirroring substrate preferences in the field. Sexual dimorphism and dwarfism within a cohort complicated ageing maggots using size, but the use of developmental events (e.g. ecdysis) allowed ages to be determined unambiguously. Separate species status was supported for the previously synonymised C. chloropyga and C. putoria, by differences in maggot behaviour, larval growth rates and temperature optima. The proportion of total development time assigned to each larval instar and pupariation was variable among temperatures, but similar between congeneric species. Thirdly, since a negative linear relationship was found to occur between the developmental constant (K) and developmental zero (D₀) for both Calliphoridae and Sarcophagidae, the potential for predicting physiological parameters of unstudied taxa was investigated. Species and genera of Palaearctic origin generally had high K's and low D₀'s, and the reverse was true for the tropical taxa. It was found that both K and D₀ can be estimated for "unknown" taxa using the Felsenstein's Independent Contrasts (FIC) method of PDTree (Garland et al. 200 I), provided that branch lengths are relatively short and the phylogenetic position of the estimated taxon is unambiguous.
- Full Text:
- Date Issued: 2003
Biogeography and community structure of fishes in South African estuaries
- Authors: Harrison, Trevor D
- Date: 2003
- Subjects: Estuarine ecology -- South Africa Estuarine fishes -- South Africa Fish communities -- South Africa Biogeography -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5235 , http://hdl.handle.net/10962/d1005078
- Description: The biogeography and community structure of the fishes of South African estuaries was investigated. In all, 109 systems were examined representing two broad types: temporarily closed and permanently open estuaries. Multivariate analyses of the fish communities identified three biogeographic regions. A cool-temperate region extended along the west and southwest coasts; a warmtemperate zone stretched along the south, southeast and east coasts and a subtropical region occurred along the east coast. The boundaries of these biogeographic regions were also delineated. The general physico-chemical characteristics of the estuaries within the three biogeographic regions also reflected regional differences in climate, rainfall and ocean conditions. Estuarine temperatures followed the trend for marine coastal waters, decreasing from subtropical estuaries toward cool-temperate systems. The low rainfall and runoff in the warm-temperate region together with high evaporation rates and strong seawater input resulted in higher salinities in these estuaries. These factors also accounted for the predominantly clearer waters in warm-temperate estuaries. The estuaries in the three biogeographic regions were also shown to contain somewhat distinctive fish assemblages. Temperature and salinity appeared to be the two main factors affecting the distribution and abundance of fishes in South African estuaries. Subtropical systems were characterised by fishes mostly of tropical origin as well as certain south coast endemic species. Warm-temperate estuaries were dominated by endemic taxa with some tropical species also present. The fish fauna of cooltemperate estuaries mostly comprised south coast endemic species with cosmopolitan and temperate taxa also present. Certain functional components of the ichthyofauna also exhibited slight differences between regions. Freshwater fishes were a major component of closed subtropical estuaries while estuarine resident species were more abundant in warm-temperate estuaries. Overall, estuarine-dependent marine species dominated the fish fauna of the estuaries in all biogeographic regions, signifying that South African estuaries perform a vital nursery function for this group of fishes. Slight differences were also apparent in the trophic structure of the fishes; these were related to environmental differences between regions. Zooplanktivores and fishes that feed on aquatic macrophytes/invertebrates assumed a relatively higher importance in warm-temperate systems. Overall, detritivores dominated the estuarine fish fauna in all regions, indicating that detritus forms the main energy source in South African estuaries.
- Full Text:
- Date Issued: 2003
- Authors: Harrison, Trevor D
- Date: 2003
- Subjects: Estuarine ecology -- South Africa Estuarine fishes -- South Africa Fish communities -- South Africa Biogeography -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5235 , http://hdl.handle.net/10962/d1005078
- Description: The biogeography and community structure of the fishes of South African estuaries was investigated. In all, 109 systems were examined representing two broad types: temporarily closed and permanently open estuaries. Multivariate analyses of the fish communities identified three biogeographic regions. A cool-temperate region extended along the west and southwest coasts; a warmtemperate zone stretched along the south, southeast and east coasts and a subtropical region occurred along the east coast. The boundaries of these biogeographic regions were also delineated. The general physico-chemical characteristics of the estuaries within the three biogeographic regions also reflected regional differences in climate, rainfall and ocean conditions. Estuarine temperatures followed the trend for marine coastal waters, decreasing from subtropical estuaries toward cool-temperate systems. The low rainfall and runoff in the warm-temperate region together with high evaporation rates and strong seawater input resulted in higher salinities in these estuaries. These factors also accounted for the predominantly clearer waters in warm-temperate estuaries. The estuaries in the three biogeographic regions were also shown to contain somewhat distinctive fish assemblages. Temperature and salinity appeared to be the two main factors affecting the distribution and abundance of fishes in South African estuaries. Subtropical systems were characterised by fishes mostly of tropical origin as well as certain south coast endemic species. Warm-temperate estuaries were dominated by endemic taxa with some tropical species also present. The fish fauna of cooltemperate estuaries mostly comprised south coast endemic species with cosmopolitan and temperate taxa also present. Certain functional components of the ichthyofauna also exhibited slight differences between regions. Freshwater fishes were a major component of closed subtropical estuaries while estuarine resident species were more abundant in warm-temperate estuaries. Overall, estuarine-dependent marine species dominated the fish fauna of the estuaries in all biogeographic regions, signifying that South African estuaries perform a vital nursery function for this group of fishes. Slight differences were also apparent in the trophic structure of the fishes; these were related to environmental differences between regions. Zooplanktivores and fishes that feed on aquatic macrophytes/invertebrates assumed a relatively higher importance in warm-temperate systems. Overall, detritivores dominated the estuarine fish fauna in all regions, indicating that detritus forms the main energy source in South African estuaries.
- Full Text:
- Date Issued: 2003
Botanical inventory and phenology in relation to foraging behaviour of the Cape honeybees (Apis Mellifera Capensis) at a site in the Eastern Cape, South Africa
- Authors: Merti, Admassu Addi
- Date: 2003
- Subjects: Fynbos -- South Africa -- Eastern Cape , Honeybee -- South Africa -- Eastern Cape , Honey plants -- South Africa -- Eastern Cape , Honeybee -- South Africa -- Eastern Cape -- Food , Plant ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4214 , http://hdl.handle.net/10962/d1003783 , Fynbos -- South Africa -- Eastern Cape , Honeybee -- South Africa -- Eastern Cape , Honey plants -- South Africa -- Eastern Cape , Honeybee -- South Africa -- Eastern Cape -- Food , Plant ecology -- South Africa -- Eastern Cape
- Description: From an apicultural point of view the Cape fynbos is under-utilised and our knowledge of its utilization by the Cape honeybees is incomplete. The key aim of this study was to test the hypothesis that the Cape honeybees utilize the fynbos species as the preferred source of nectar and pollen. Subsidiary aims included distinguishing vegetation communities in the area, identifying pollen and nectar sources, the relationship between brood population and seasonal pollen collection patterns, examining the effect of meteorological factors on pollen collection. The study site was on Rivendell Farm within the Eastern Cape Albany district: an area of high species richness. A checklist of vascular plant species was produced revealing 97 families, 271 genera and 448 species. A classification by two-way indicator species (TWINSPAN) recognized seven vegetation communities: Forest, Bush clumps, Acacia savanna, Grassland, Grassy fynbos, Fynbos and Shrubland. Direct field observations of the foraging of Cape honeybees identified 54 nectar and pollen source plant species. Honeybee pollen loads trapped from four colonies of hives identified 37 pollen source plants of which Metalasia muricata, Eucalyptus grandis, Eucalyptus camaldulensis, Erica chamissonis, Helichrysum odoratissimum, Helichrysum anomalum, Crassula cultrata and Acacia longifolia were the predominant pollen source plants. It was also found that 60% of pollen yield derived from fynbos vegetation. The pollen source plants came from both Cape endemic and from nonendemic species. Thus we reject the hypothesis that Cape honeybees selectively forage fynbos species as a preferred source of pollen and nectar. The examination of the effect of temperature, wind-speed and temperature on pollen collection activity of honeybees revealed that: a temperature range of between 14°C to 26°C was optimal for pollen collection; wind speeds of up to 4m/s were conducive for pollen collection; relative humidity was found to have no significant influence on pollen collection. Pollen collection and brood rearing patterns are positively correlated with flowering intensities, but we found in our Eastern Cape study site that brood rearing was not limited to the spring flowering season but did extend to the end of summer. In order to determine the available nectar yield of common plant species hourly secretion of nectar volumes was measured for 24 hours to determine the variation of available nectar during different times of the day. In all nectar producing species the nectar volume was high in the early morning and declined as the day progressed. We found that the volume of available nectar was affected by prevailing temperature and humidity around the flowers.
- Full Text:
- Date Issued: 2003
- Authors: Merti, Admassu Addi
- Date: 2003
- Subjects: Fynbos -- South Africa -- Eastern Cape , Honeybee -- South Africa -- Eastern Cape , Honey plants -- South Africa -- Eastern Cape , Honeybee -- South Africa -- Eastern Cape -- Food , Plant ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4214 , http://hdl.handle.net/10962/d1003783 , Fynbos -- South Africa -- Eastern Cape , Honeybee -- South Africa -- Eastern Cape , Honey plants -- South Africa -- Eastern Cape , Honeybee -- South Africa -- Eastern Cape -- Food , Plant ecology -- South Africa -- Eastern Cape
- Description: From an apicultural point of view the Cape fynbos is under-utilised and our knowledge of its utilization by the Cape honeybees is incomplete. The key aim of this study was to test the hypothesis that the Cape honeybees utilize the fynbos species as the preferred source of nectar and pollen. Subsidiary aims included distinguishing vegetation communities in the area, identifying pollen and nectar sources, the relationship between brood population and seasonal pollen collection patterns, examining the effect of meteorological factors on pollen collection. The study site was on Rivendell Farm within the Eastern Cape Albany district: an area of high species richness. A checklist of vascular plant species was produced revealing 97 families, 271 genera and 448 species. A classification by two-way indicator species (TWINSPAN) recognized seven vegetation communities: Forest, Bush clumps, Acacia savanna, Grassland, Grassy fynbos, Fynbos and Shrubland. Direct field observations of the foraging of Cape honeybees identified 54 nectar and pollen source plant species. Honeybee pollen loads trapped from four colonies of hives identified 37 pollen source plants of which Metalasia muricata, Eucalyptus grandis, Eucalyptus camaldulensis, Erica chamissonis, Helichrysum odoratissimum, Helichrysum anomalum, Crassula cultrata and Acacia longifolia were the predominant pollen source plants. It was also found that 60% of pollen yield derived from fynbos vegetation. The pollen source plants came from both Cape endemic and from nonendemic species. Thus we reject the hypothesis that Cape honeybees selectively forage fynbos species as a preferred source of pollen and nectar. The examination of the effect of temperature, wind-speed and temperature on pollen collection activity of honeybees revealed that: a temperature range of between 14°C to 26°C was optimal for pollen collection; wind speeds of up to 4m/s were conducive for pollen collection; relative humidity was found to have no significant influence on pollen collection. Pollen collection and brood rearing patterns are positively correlated with flowering intensities, but we found in our Eastern Cape study site that brood rearing was not limited to the spring flowering season but did extend to the end of summer. In order to determine the available nectar yield of common plant species hourly secretion of nectar volumes was measured for 24 hours to determine the variation of available nectar during different times of the day. In all nectar producing species the nectar volume was high in the early morning and declined as the day progressed. We found that the volume of available nectar was affected by prevailing temperature and humidity around the flowers.
- Full Text:
- Date Issued: 2003
Building blocks of marketing strategy for targeting local biltong hunters: an evaluation
- Authors: Van Eyk, Marlé
- Date: 2003
- Subjects: Marketing , Big game hunting -- South Africa -- Eastern Cape -- Marketing , Dried meat -- South Africa -- Eastern Cape , Hunters -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech (Marketing)
- Identifier: vital:10770 , http://hdl.handle.net/10948/207 , Marketing , Big game hunting -- South Africa -- Eastern Cape -- Marketing , Dried meat -- South Africa -- Eastern Cape , Hunters -- South Africa -- Eastern Cape
- Description: Game ranch owners are spoilt by the high prices overseas hunters are prepared to pay, and tend to forget that in the long term it is the local market that may ensure the survival of the game industry. More effort should therefore be put into marketing hunting opportunities for the local hunter. This research focused on analysing the typical building blocks of marketing strategy applicable to service organizations. This was done to determine and evaluate the building blocks of marketing strategy applicable to game ranches in the Eastern Cape Province who are targeting local biltong hunters. A literature review was conducted to determine the ideal building blocks of marketing strategy for service organizations such as game ranches. Thereafter, a survey was conducted by means of a questionnaire to determine the ranchers' perceptions of marketing and evaluate their marketing strategies. Most of the respondents: had a fair idea of what marketing entails; were unaware of the thread that links customer expectations, satisfaction and loyalty; realized the importance of relationship marketing with external markets, but not with internal markets; perceived direct competition as their biggest threat, while other travel opportunities were seen as the most important substitute for hunting; mainly positioned themselves based on the features the ranch offered, and believed that the standard of service delivery and physical features of the ranch (the nature of the offering) were their important competitive advantages. The study proposes that the framework of building blocks of marketing strategy, designed by the researcher be used as a tool with which marketing strategies for game ranches in the Eastern Cape Province targeting local biltong hunters could be developed. Additional research on topics such as advertising and the various market opportunity strategies of diversification and product development, could lead to improvement and modification of this framework, making it an even more powerful tool in developing marketing strategies.
- Full Text:
- Date Issued: 2003
- Authors: Van Eyk, Marlé
- Date: 2003
- Subjects: Marketing , Big game hunting -- South Africa -- Eastern Cape -- Marketing , Dried meat -- South Africa -- Eastern Cape , Hunters -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech (Marketing)
- Identifier: vital:10770 , http://hdl.handle.net/10948/207 , Marketing , Big game hunting -- South Africa -- Eastern Cape -- Marketing , Dried meat -- South Africa -- Eastern Cape , Hunters -- South Africa -- Eastern Cape
- Description: Game ranch owners are spoilt by the high prices overseas hunters are prepared to pay, and tend to forget that in the long term it is the local market that may ensure the survival of the game industry. More effort should therefore be put into marketing hunting opportunities for the local hunter. This research focused on analysing the typical building blocks of marketing strategy applicable to service organizations. This was done to determine and evaluate the building blocks of marketing strategy applicable to game ranches in the Eastern Cape Province who are targeting local biltong hunters. A literature review was conducted to determine the ideal building blocks of marketing strategy for service organizations such as game ranches. Thereafter, a survey was conducted by means of a questionnaire to determine the ranchers' perceptions of marketing and evaluate their marketing strategies. Most of the respondents: had a fair idea of what marketing entails; were unaware of the thread that links customer expectations, satisfaction and loyalty; realized the importance of relationship marketing with external markets, but not with internal markets; perceived direct competition as their biggest threat, while other travel opportunities were seen as the most important substitute for hunting; mainly positioned themselves based on the features the ranch offered, and believed that the standard of service delivery and physical features of the ranch (the nature of the offering) were their important competitive advantages. The study proposes that the framework of building blocks of marketing strategy, designed by the researcher be used as a tool with which marketing strategies for game ranches in the Eastern Cape Province targeting local biltong hunters could be developed. Additional research on topics such as advertising and the various market opportunity strategies of diversification and product development, could lead to improvement and modification of this framework, making it an even more powerful tool in developing marketing strategies.
- Full Text:
- Date Issued: 2003
Change and continuity : perceptions about childhood diseases among the Tumbuka of Northern Malawi
- Munthali, Alister Chaundumuka
- Authors: Munthali, Alister Chaundumuka
- Date: 2003
- Subjects: Tumbuka (African people) Ethnology -- Malawi Diseases -- Causes and theories of causation Health behavior -- Malawi Health attitudes -- Malawi Children -- Diseases -- Malawi
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2114 , http://hdl.handle.net/10962/d1007718
- Description: The objectives of this study were to determine what the Tumbuka people of northern Malawi consider to be the most dangerous childhood diseases, to explore their perceptions about the aetiology, prevention and treatment of these diseases, and to determine how such perceptions have changed over the years. The study was done in Chisinde and surrounding villages in western Rumphi District, northern Malawi. Although a household questionnaire was used to collect some quantitative data, the major data collection methods comprised participant observation, in-depth interviews with mothers with children under five and old men and women, and key informant interviews with traditional healers, traditional birth attendants, village headmen, health surveillance assistants and clinical officers. Informants in this study mentioned chikhoso chamoto, diarrhoea, malaria, measles, and conjunctivitis as the most dangerous childhood diseases in the area. Old men and women added that in the past smallpox was also a dangerous disease that affected both children and adults. Apart from measles and smallpox, community-based health workers and those at the local health centre also mentioned the same list of diseases as the most dangerous diseases prevalent among under-five children. Though health workers and informants mentioned the same diseases, the informants' perspectives about the aetiology and prevention of these diseases and the way they sought treatment during childhood illness episodes, in some cases, differed significantly from those of biomedicine. For example, while health workers said that the signs and symptoms presented by a child suffering from "chikhoso chamoto" were those of either kwashiorkor or marasmus, both young and elderly informants said that a child could contract this illness through contact with a person who had been involved in sexual intercourse. Biomedically, diarrhoea is caused by the ingestion of pathogenic agents, which are transmitted through, among other factors, drinking contaminated water and eating contaminated foods. While young men and women subscribed to this biomedical view, at the same time, just like old men and women, they also believed that if a breastfeeding mother has sexual intercourse, sperms will contaminate her breast milk and, once a child feeds on this milk, he or she will develop diarrhoea. They, in addition, associated diarrhoea with the process of teething and other infections, such as malaria and measles. In malaria-endemic areas such as Malawi, the occurrence of convulsions, splenomegaly and anaemia in children under five may be biomedically attributed to malaria. However, most informants in this study perceived these conditions as separate disease entities caused by, among other factors, witchcraft and the infringement of Tumbuka taboos relating to food, sexual intercourse and funerals. Splenomegaly and convulsions were also perceived as hereditary diseases. Such Tumbuka perceptions about the aetiology of childhood diseases also influenced their ideas about prevention and the seeking of therapy during illness episodes. Apart from measles, other childhood vaccine-preventable diseases (i.e. tetanus, diphtheria, tuberculosis, pertussis and poliomyelitis) were not mentioned, presumably because they are no longer occurring on a significant scale, which is an indication of the success of vaccination programmes. This study reveals that there is no outright rejection of vaccination services in the study area. Some mothers, though, felt pressured to go for vaccination services as they believed that non-vaccinated children were refused biomedical treatment at the local health centres when they fell ill. While young women with children under five mentioned vaccination as a preventative measure against diseases such as measles, they also mentioned other indigenous forms of 'vaccination', which included the adherence to societal taboos, the wearing of amulets, the rubbing of protective medicines into incisions, isolation of children under five (e.g. a newly born child is kept in the house, amongst other things, to protect him or her against people who are ritually considered hot because of sexual intercourse) who are susceptible to disease or those posing a threat to cause disease in children under five. For example, since diarrhoea is perceived to be caused by, among other things, a child feeding on breast milk contaminated with sperms, informants said that there is a strong need for couples to observe postpartum sexual intercourse. A couple with newly delivered twins is isolated from the village because of the belief that children will swell if they came into contact with them. Local methods of disease prevention seem therefore to depend on what is perceived to be the cause of the illness and the decision to adopt specific preventive measures depends on, among other factors, the diagnosis of the cause and of who is vulnerable. The therapy-seeking process is a hierarchical movement within and between aetiologies; at the same time, it is not a random process, but an ordered process of choices in response to negative feedback, and subject to a number of factors, such as the aetiology of the disease, distance, social costs, cost of the therapeutic intervention, availability of medicines, etc. The movement between systems (i.e. from traditional medicine to biomedicine and vice-versa) during illness episodes depends on a number of factors, including previous experiences of significant others (i.e. those close to the patient), perceptions about the chances of getting healed, the decisions of the therapy management group, etc. For example, febrile illness in children under five may be treated using herbs or antipyretics bought from the local grocery shops. When the situation worsens (e.g. accompanied by convulsions), a herbalist will be consulted or the child may be taken to the local health centre. The local health centre refers such cases to the district hospital for treatment. Because of the rapidity with which the condition worsens, informants said that sometimes such children are believed to be bewitched, hence while biomedical treatment is sought, at the same time diviners are also consulted. The therapeutic strategies people resort to during illness episodes are appropriate rational decisions, based on prevailing circumstances, knowledge, resources and outcomes. Boundaries between the different therapeutic options are not rigid, as people move from one form of therapy to another and from one mode of classification to another. Lastly, perceptions about childhood diseases have changed over the years. Old men and women mostly attribute childhood illnesses to the infringement of taboos (e.g. on . sexual intercourse), witchcraft and other supernatural forces. While young men and women also subscribe to these perceptions, they have at the same time also appropriated the biomedical disease explanatory models. These biomedical models were learnt at school, acquired during health education sessions conducted by health workers in the communities as well as during under-five clinics, and health education programmes conducted on the national radio station. Younger people, more frequently than older people, thus move within and between aetiological models in the manner described above.
- Full Text:
- Date Issued: 2003
- Authors: Munthali, Alister Chaundumuka
- Date: 2003
- Subjects: Tumbuka (African people) Ethnology -- Malawi Diseases -- Causes and theories of causation Health behavior -- Malawi Health attitudes -- Malawi Children -- Diseases -- Malawi
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2114 , http://hdl.handle.net/10962/d1007718
- Description: The objectives of this study were to determine what the Tumbuka people of northern Malawi consider to be the most dangerous childhood diseases, to explore their perceptions about the aetiology, prevention and treatment of these diseases, and to determine how such perceptions have changed over the years. The study was done in Chisinde and surrounding villages in western Rumphi District, northern Malawi. Although a household questionnaire was used to collect some quantitative data, the major data collection methods comprised participant observation, in-depth interviews with mothers with children under five and old men and women, and key informant interviews with traditional healers, traditional birth attendants, village headmen, health surveillance assistants and clinical officers. Informants in this study mentioned chikhoso chamoto, diarrhoea, malaria, measles, and conjunctivitis as the most dangerous childhood diseases in the area. Old men and women added that in the past smallpox was also a dangerous disease that affected both children and adults. Apart from measles and smallpox, community-based health workers and those at the local health centre also mentioned the same list of diseases as the most dangerous diseases prevalent among under-five children. Though health workers and informants mentioned the same diseases, the informants' perspectives about the aetiology and prevention of these diseases and the way they sought treatment during childhood illness episodes, in some cases, differed significantly from those of biomedicine. For example, while health workers said that the signs and symptoms presented by a child suffering from "chikhoso chamoto" were those of either kwashiorkor or marasmus, both young and elderly informants said that a child could contract this illness through contact with a person who had been involved in sexual intercourse. Biomedically, diarrhoea is caused by the ingestion of pathogenic agents, which are transmitted through, among other factors, drinking contaminated water and eating contaminated foods. While young men and women subscribed to this biomedical view, at the same time, just like old men and women, they also believed that if a breastfeeding mother has sexual intercourse, sperms will contaminate her breast milk and, once a child feeds on this milk, he or she will develop diarrhoea. They, in addition, associated diarrhoea with the process of teething and other infections, such as malaria and measles. In malaria-endemic areas such as Malawi, the occurrence of convulsions, splenomegaly and anaemia in children under five may be biomedically attributed to malaria. However, most informants in this study perceived these conditions as separate disease entities caused by, among other factors, witchcraft and the infringement of Tumbuka taboos relating to food, sexual intercourse and funerals. Splenomegaly and convulsions were also perceived as hereditary diseases. Such Tumbuka perceptions about the aetiology of childhood diseases also influenced their ideas about prevention and the seeking of therapy during illness episodes. Apart from measles, other childhood vaccine-preventable diseases (i.e. tetanus, diphtheria, tuberculosis, pertussis and poliomyelitis) were not mentioned, presumably because they are no longer occurring on a significant scale, which is an indication of the success of vaccination programmes. This study reveals that there is no outright rejection of vaccination services in the study area. Some mothers, though, felt pressured to go for vaccination services as they believed that non-vaccinated children were refused biomedical treatment at the local health centres when they fell ill. While young women with children under five mentioned vaccination as a preventative measure against diseases such as measles, they also mentioned other indigenous forms of 'vaccination', which included the adherence to societal taboos, the wearing of amulets, the rubbing of protective medicines into incisions, isolation of children under five (e.g. a newly born child is kept in the house, amongst other things, to protect him or her against people who are ritually considered hot because of sexual intercourse) who are susceptible to disease or those posing a threat to cause disease in children under five. For example, since diarrhoea is perceived to be caused by, among other things, a child feeding on breast milk contaminated with sperms, informants said that there is a strong need for couples to observe postpartum sexual intercourse. A couple with newly delivered twins is isolated from the village because of the belief that children will swell if they came into contact with them. Local methods of disease prevention seem therefore to depend on what is perceived to be the cause of the illness and the decision to adopt specific preventive measures depends on, among other factors, the diagnosis of the cause and of who is vulnerable. The therapy-seeking process is a hierarchical movement within and between aetiologies; at the same time, it is not a random process, but an ordered process of choices in response to negative feedback, and subject to a number of factors, such as the aetiology of the disease, distance, social costs, cost of the therapeutic intervention, availability of medicines, etc. The movement between systems (i.e. from traditional medicine to biomedicine and vice-versa) during illness episodes depends on a number of factors, including previous experiences of significant others (i.e. those close to the patient), perceptions about the chances of getting healed, the decisions of the therapy management group, etc. For example, febrile illness in children under five may be treated using herbs or antipyretics bought from the local grocery shops. When the situation worsens (e.g. accompanied by convulsions), a herbalist will be consulted or the child may be taken to the local health centre. The local health centre refers such cases to the district hospital for treatment. Because of the rapidity with which the condition worsens, informants said that sometimes such children are believed to be bewitched, hence while biomedical treatment is sought, at the same time diviners are also consulted. The therapeutic strategies people resort to during illness episodes are appropriate rational decisions, based on prevailing circumstances, knowledge, resources and outcomes. Boundaries between the different therapeutic options are not rigid, as people move from one form of therapy to another and from one mode of classification to another. Lastly, perceptions about childhood diseases have changed over the years. Old men and women mostly attribute childhood illnesses to the infringement of taboos (e.g. on . sexual intercourse), witchcraft and other supernatural forces. While young men and women also subscribe to these perceptions, they have at the same time also appropriated the biomedical disease explanatory models. These biomedical models were learnt at school, acquired during health education sessions conducted by health workers in the communities as well as during under-five clinics, and health education programmes conducted on the national radio station. Younger people, more frequently than older people, thus move within and between aetiological models in the manner described above.
- Full Text:
- Date Issued: 2003
Comparing models for predicting species' potential distributions : a case study using correlative and mechanistic predictive modelling techniques
- Robertson, Mark P, Peter, Craig I, Villet, Martin H, Ripley, Bradford S
- Authors: Robertson, Mark P , Peter, Craig I , Villet, Martin H , Ripley, Bradford S
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6539 , http://hdl.handle.net/10962/d1005980 , http://dx.doi.org/10.1016/S0304-3800(03)00028-0
- Description: Models used to predict species’ potential distributions have been described as either correlative or mechanistic. We attempted to determine whether correlative models could perform as well as mechanistic models for predicting species potential distributions, using a case study. We compared potential distribution predictions made for a coastal dune plant (Scaevola plumieri) along the coast of South Africa, using a mechanistic model based on summer water balance (SWB), and two correlative models (a profile and a group discrimination technique). The profile technique was based on principal components analysis (PCA) and the group-discrimination technique was based on multiple logistic regression (LR). Kappa (κ) statistics were used to objectively assess model performance and model agreement. Model performance was calculated by measuring the levels of agreement (using κ) between a set of testing localities (distribution records not used for model building) and each of the model predictions. Using published interpretive guidelines for the kappa statistic, model performance was “excellent” for the SWB model (κ=0.852), perfect for the LR model (κ=1.000), and “very good” for the PCA model (κ=0.721). Model agreement was calculated by measuring the level of agreement between the mechanistic model and the two correlative models. There was “good” model agreement between the SWB and PCA models (κ=0.679) and “very good” agreement between the SWB and LR models (κ=0.786). The results suggest that correlative models can perform as well as or better than simple mechanistic models. The predictions generated from these three modelling designs are likely to generate different insights into the potential distribution and biology of the target organism and may be appropriate in different situations. The choice of model is likely to be influenced by the aims of the study, the biology of the target organism, the level of knowledge the target organism’s biology, and data quality.
- Full Text:
- Date Issued: 2003
- Authors: Robertson, Mark P , Peter, Craig I , Villet, Martin H , Ripley, Bradford S
- Date: 2003
- Language: English
- Type: Article
- Identifier: vital:6539 , http://hdl.handle.net/10962/d1005980 , http://dx.doi.org/10.1016/S0304-3800(03)00028-0
- Description: Models used to predict species’ potential distributions have been described as either correlative or mechanistic. We attempted to determine whether correlative models could perform as well as mechanistic models for predicting species potential distributions, using a case study. We compared potential distribution predictions made for a coastal dune plant (Scaevola plumieri) along the coast of South Africa, using a mechanistic model based on summer water balance (SWB), and two correlative models (a profile and a group discrimination technique). The profile technique was based on principal components analysis (PCA) and the group-discrimination technique was based on multiple logistic regression (LR). Kappa (κ) statistics were used to objectively assess model performance and model agreement. Model performance was calculated by measuring the levels of agreement (using κ) between a set of testing localities (distribution records not used for model building) and each of the model predictions. Using published interpretive guidelines for the kappa statistic, model performance was “excellent” for the SWB model (κ=0.852), perfect for the LR model (κ=1.000), and “very good” for the PCA model (κ=0.721). Model agreement was calculated by measuring the level of agreement between the mechanistic model and the two correlative models. There was “good” model agreement between the SWB and PCA models (κ=0.679) and “very good” agreement between the SWB and LR models (κ=0.786). The results suggest that correlative models can perform as well as or better than simple mechanistic models. The predictions generated from these three modelling designs are likely to generate different insights into the potential distribution and biology of the target organism and may be appropriate in different situations. The choice of model is likely to be influenced by the aims of the study, the biology of the target organism, the level of knowledge the target organism’s biology, and data quality.
- Full Text:
- Date Issued: 2003
Effect of photoperiod on sexual development, growth and production of quail (coturnix coturnix japonica)
- Authors: De Jager, Pieter Herodes
- Date: 2003
- Subjects: Quails , Quails -- Growth , Quails -- Effect of light on , Photoperiodism
- Language: English
- Type: Thesis , Masters , MTech (Agricultural Management)
- Identifier: vital:10969 , http://hdl.handle.net/10948/227 , Quails , Quails -- Growth , Quails -- Effect of light on , Photoperiodism
- Description: The aim of the study was to determine the effect of photoperiod on production of quail in South Africa. Day old chicks were randomly divided into two groups. One group (n=74) received continuous light (LL) while the other group (n=77) received 13 h of light (LD) per day. Traits measured were sexual characteristics (age at sexual maturity and testis weight, egg production and egg weight) and growth (body weight) development in males and females respectively. Significant differences in growth existed between sexes; females were 171.44±17.15 and 182.91±17.75 g compared to the 151.77±13.20 and 155.00±16.86 g for males in both LL and LD groups respectively. Both males and females in the LL group initially outperformed the LD group in growth rate but, by day 72 the LD group had compensated and were 4.6% heavier than the LL group. A similar trend was observed for sexual maturity between the LL and LD groups. However, photoperiod did significantly influence initial egg production in favour of the LL group. The LL group had 80% of the females in production by day 44 compared to the 60% of the LD group. The initial egg weight of the LL group was 14 % higher than those of the LD group. Quail subjected to continuous light attained earlier sexual maturity and production with lower final weight compared to quail subjected to an intermediate photoperiod. The application of a longer photoperiod would therefore favour an egg production system.
- Full Text:
- Date Issued: 2003
- Authors: De Jager, Pieter Herodes
- Date: 2003
- Subjects: Quails , Quails -- Growth , Quails -- Effect of light on , Photoperiodism
- Language: English
- Type: Thesis , Masters , MTech (Agricultural Management)
- Identifier: vital:10969 , http://hdl.handle.net/10948/227 , Quails , Quails -- Growth , Quails -- Effect of light on , Photoperiodism
- Description: The aim of the study was to determine the effect of photoperiod on production of quail in South Africa. Day old chicks were randomly divided into two groups. One group (n=74) received continuous light (LL) while the other group (n=77) received 13 h of light (LD) per day. Traits measured were sexual characteristics (age at sexual maturity and testis weight, egg production and egg weight) and growth (body weight) development in males and females respectively. Significant differences in growth existed between sexes; females were 171.44±17.15 and 182.91±17.75 g compared to the 151.77±13.20 and 155.00±16.86 g for males in both LL and LD groups respectively. Both males and females in the LL group initially outperformed the LD group in growth rate but, by day 72 the LD group had compensated and were 4.6% heavier than the LL group. A similar trend was observed for sexual maturity between the LL and LD groups. However, photoperiod did significantly influence initial egg production in favour of the LL group. The LL group had 80% of the females in production by day 44 compared to the 60% of the LD group. The initial egg weight of the LL group was 14 % higher than those of the LD group. Quail subjected to continuous light attained earlier sexual maturity and production with lower final weight compared to quail subjected to an intermediate photoperiod. The application of a longer photoperiod would therefore favour an egg production system.
- Full Text:
- Date Issued: 2003
Effects of sustained Russian wheat aphid (Diuraphis noxia Mordvilko) feeding on leaf blades of wheat (Triticum aestivum L. cv Adamtas)
- Authors: Matsiliza, Babalwa
- Date: 2003
- Subjects: Russian wheat aphid Wheat -- Diseases and pests
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4213 , http://hdl.handle.net/10962/d1003782
- Description: Penetration of sink as well as source leaves of wheat plants by the Russian wheat aphid, Diuraphis noxia (Mordvilko) was investigated using light, fluorescence and transmission electron techniques, to determine the feeding strategies adopted by the aphid in penetrating and successfully feeding from the phloem, and to assess the structural effects of the probing and feeding behaviour of D. noxia on the feeding sites. Examination of aphid-infested sink, as well as source leaf tissue, showed that D.noxia probed in cells of the vascular bundle more frequently than mesophyll cells. Within the vascular bundle, thin-walled sieve tubes were visited (probed) more than the other cells. In sink leaf material, 68 of 82 (83%) stylets and stylet tracks encountered during the examination of 1000 serial sections (from 5 different plants) terminated in thin-walled sieve tubes and only 14 (17%) in thick-walled sieve tubes. Thin-walled sieve tubes were visited more significantly than thick-walled sieve tubes. However, examination of the aphid.,.infested sink leaf on a per centimetre basis, from the tip of the leaf, revealed that thick-walled sieve tubes in the area closest to the tip (0-2cm from the tip) were as attractive to the aphid as were thin-walled sieve tubes, with no significant difference in the number of times thick- and thin-walled sieve tubes were probed in this area. Some 2-4cm from the tip however, thinwalled sieve tubes were significantly more probed and therefore more attractive than thick-walled sieve tubes. Examination of 2000 serial sections using aphid-infested source leaf tissue, showed that the thin-walled sieve tubes were significantly more probed than thickwalled sieve tubes, along the whole leaf, expressed as a total of all leaves, as well as on a per centimetre basis along the length of the leaf, with 212 (95%) of 222 terminations within the thin-walled sieve tubes and only 10 (5%) in thick-walledsieve tubes. The aphid probed the small vascular bundles (loading bundles) many more times than intermediate or large transport vascular bundles, in sink as well as source leaf. Of a total of 82 stylets and stylet tracks encountered in sink leaf tissue, 31 terminated in small vascular bundles ang the remaining 28 and 16 were located within large and intermediate vascular bundles respectively. In source leaf tissue 121 of 222 stylets and stylet tracks encountered were associated with small vascular bundles and only 58 tracks and 43 tracks with intermediate and large vascular bundles, respectively. The effect of sustained RWA feeding on the transport capacity was examined after the application of 5,6 carboxyfluoresceine diacetate (5,6-CFDA) in control (sink and source leaf tissue) and aphid-infested (source) wheat leaves, using fluorescence microscopy. After 3h acropetal longitudinal transport of 5,6-CF had occurred in sink leaves in longitudinal veins, as well as a lateral transfer via cross veins and subsequent unloading into mesophyll cells close to the tip of the leaf was observed. In control leaf tissue, the fluorescence front was detected up to about 5cm from the point of application and was only associated with the phloem and not unloaded. In contrast, aphid-infested leaf tissue showed very little 5,6-CF transport, being limited to 2cm or less from the point of application. Structural damage to the phloem in general and to the sieve tubes in particular within of control and infested wheat leaves was investigated using transmission electron microscopy (TEM). In addition, leaf strips were mounted in aniline blue to visualise callose deposition using the fluorescence microscopy. At the TEM level. infested leaf tissue showed various abnormalities, which included destruction of cell contents, membrane damage and subsequent loss of cell contents. TEM studies suggest severe osmotic shock resulted from the aphid's probing. Examination of leaf tissue using fluorescence microscopy showed that there was very little characteristic aniline blue-stained callose visible in control leaf tissue, other than the thin diffuse patches along the sieve plates and punctate spots associated with pore plasmodesmatal areas and plasmodesmatal aggregates. In contrast, the aphid-infested leaf tissue was heavily callosed, with callose deposited not only within the phloem tissue but also in neighbouring vascular parE:}nchyma cells as well. The data collectively suggest that D. noxia feeds preferentially within thin-walled sieve tubes, within the small longitudinal vascular bundles in sink , as well source leaf tissue. Based upon the data presented here the thin-walled sieve tubes in the wheat leaf appear to be more attractive to the aphid and that they are probably more functional in terms of transport system and unlo?lding in sink leaves. Aniline blue stained leaf material that had previously hosted large aphid colonies showed evidence of extensive callose deposits 24 to 36h after the aphids were removed, suggesting that the aphids caused severe mechanical damage to the vascular tissue and mesohyll cells as well. Damage (transient or more permanent) and the subsequent deposition of wound callose, disrupted phloem transport and hence the export of photoassimilate from the leaves.
- Full Text:
- Date Issued: 2003
- Authors: Matsiliza, Babalwa
- Date: 2003
- Subjects: Russian wheat aphid Wheat -- Diseases and pests
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4213 , http://hdl.handle.net/10962/d1003782
- Description: Penetration of sink as well as source leaves of wheat plants by the Russian wheat aphid, Diuraphis noxia (Mordvilko) was investigated using light, fluorescence and transmission electron techniques, to determine the feeding strategies adopted by the aphid in penetrating and successfully feeding from the phloem, and to assess the structural effects of the probing and feeding behaviour of D. noxia on the feeding sites. Examination of aphid-infested sink, as well as source leaf tissue, showed that D.noxia probed in cells of the vascular bundle more frequently than mesophyll cells. Within the vascular bundle, thin-walled sieve tubes were visited (probed) more than the other cells. In sink leaf material, 68 of 82 (83%) stylets and stylet tracks encountered during the examination of 1000 serial sections (from 5 different plants) terminated in thin-walled sieve tubes and only 14 (17%) in thick-walled sieve tubes. Thin-walled sieve tubes were visited more significantly than thick-walled sieve tubes. However, examination of the aphid.,.infested sink leaf on a per centimetre basis, from the tip of the leaf, revealed that thick-walled sieve tubes in the area closest to the tip (0-2cm from the tip) were as attractive to the aphid as were thin-walled sieve tubes, with no significant difference in the number of times thick- and thin-walled sieve tubes were probed in this area. Some 2-4cm from the tip however, thinwalled sieve tubes were significantly more probed and therefore more attractive than thick-walled sieve tubes. Examination of 2000 serial sections using aphid-infested source leaf tissue, showed that the thin-walled sieve tubes were significantly more probed than thickwalled sieve tubes, along the whole leaf, expressed as a total of all leaves, as well as on a per centimetre basis along the length of the leaf, with 212 (95%) of 222 terminations within the thin-walled sieve tubes and only 10 (5%) in thick-walledsieve tubes. The aphid probed the small vascular bundles (loading bundles) many more times than intermediate or large transport vascular bundles, in sink as well as source leaf. Of a total of 82 stylets and stylet tracks encountered in sink leaf tissue, 31 terminated in small vascular bundles ang the remaining 28 and 16 were located within large and intermediate vascular bundles respectively. In source leaf tissue 121 of 222 stylets and stylet tracks encountered were associated with small vascular bundles and only 58 tracks and 43 tracks with intermediate and large vascular bundles, respectively. The effect of sustained RWA feeding on the transport capacity was examined after the application of 5,6 carboxyfluoresceine diacetate (5,6-CFDA) in control (sink and source leaf tissue) and aphid-infested (source) wheat leaves, using fluorescence microscopy. After 3h acropetal longitudinal transport of 5,6-CF had occurred in sink leaves in longitudinal veins, as well as a lateral transfer via cross veins and subsequent unloading into mesophyll cells close to the tip of the leaf was observed. In control leaf tissue, the fluorescence front was detected up to about 5cm from the point of application and was only associated with the phloem and not unloaded. In contrast, aphid-infested leaf tissue showed very little 5,6-CF transport, being limited to 2cm or less from the point of application. Structural damage to the phloem in general and to the sieve tubes in particular within of control and infested wheat leaves was investigated using transmission electron microscopy (TEM). In addition, leaf strips were mounted in aniline blue to visualise callose deposition using the fluorescence microscopy. At the TEM level. infested leaf tissue showed various abnormalities, which included destruction of cell contents, membrane damage and subsequent loss of cell contents. TEM studies suggest severe osmotic shock resulted from the aphid's probing. Examination of leaf tissue using fluorescence microscopy showed that there was very little characteristic aniline blue-stained callose visible in control leaf tissue, other than the thin diffuse patches along the sieve plates and punctate spots associated with pore plasmodesmatal areas and plasmodesmatal aggregates. In contrast, the aphid-infested leaf tissue was heavily callosed, with callose deposited not only within the phloem tissue but also in neighbouring vascular parE:}nchyma cells as well. The data collectively suggest that D. noxia feeds preferentially within thin-walled sieve tubes, within the small longitudinal vascular bundles in sink , as well source leaf tissue. Based upon the data presented here the thin-walled sieve tubes in the wheat leaf appear to be more attractive to the aphid and that they are probably more functional in terms of transport system and unlo?lding in sink leaves. Aniline blue stained leaf material that had previously hosted large aphid colonies showed evidence of extensive callose deposits 24 to 36h after the aphids were removed, suggesting that the aphids caused severe mechanical damage to the vascular tissue and mesohyll cells as well. Damage (transient or more permanent) and the subsequent deposition of wound callose, disrupted phloem transport and hence the export of photoassimilate from the leaves.
- Full Text:
- Date Issued: 2003