Nearest-neighbour analysis and the prevelance of woody plant competition in South African savannas
- Authors: Shackleton, Charlie M
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181640 , vital:43754 , xlink:href="https://doi.org/10.1023/A:1014795505362"
- Description: Inter- and intra-specific competition has long been regarded as a significant determinant of the structure and function of woody plant communities in African savannas. The most widely used approach to detect the presence or absence of competition has been the use of nearest-neighbour methods. Although several studies have been published reporting the presence of competition in Acacia dominated communities, less than 20 plots have been sampled across all these studies. Results from broad-leaved communities are variable, and also based on a small sample number. Consequently, this study sought to assess the prevalence of competition from a large number of savanna sites (45), and to identify abiotic and biotic factors characterising sites with competition relative to those without. Using the nearest-neighbour method only four sites (9.3%) indicated the presence of inter-specific competition; two were Acacia dominated communities (18.2% of Acacia sites) and two were broad-leaved communities (7.7%). These four sites had a significantly higher mean annual rainfall and fewer woody species than sites without inter-specific competition. There were also significant relationships between the inter-specific competition index and the dominance index and the number of species at a site. In terms of intra-specific competition only ten of the 31 sites tested revealed a significant correlation between nearest-neighbour distance and summed canopy volume of the two neighbours. Seven were for Acacia species (55.6% of the Acacia species comparisons) and three were for broad-leaved species (21.4% of the broad-leaved species comparisons). Sites lacking evidence of intra-specific competition were at a significantly lower slope position and had a smaller proportion of small stems. The lower prevalence of competition in South African savannas detected in this study using the same method as previous studies is discussed, and the appropriateness of nearest-neighbour analysis is examined.
- Full Text:
- Date Issued: 2002
- Authors: Shackleton, Charlie M
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181640 , vital:43754 , xlink:href="https://doi.org/10.1023/A:1014795505362"
- Description: Inter- and intra-specific competition has long been regarded as a significant determinant of the structure and function of woody plant communities in African savannas. The most widely used approach to detect the presence or absence of competition has been the use of nearest-neighbour methods. Although several studies have been published reporting the presence of competition in Acacia dominated communities, less than 20 plots have been sampled across all these studies. Results from broad-leaved communities are variable, and also based on a small sample number. Consequently, this study sought to assess the prevalence of competition from a large number of savanna sites (45), and to identify abiotic and biotic factors characterising sites with competition relative to those without. Using the nearest-neighbour method only four sites (9.3%) indicated the presence of inter-specific competition; two were Acacia dominated communities (18.2% of Acacia sites) and two were broad-leaved communities (7.7%). These four sites had a significantly higher mean annual rainfall and fewer woody species than sites without inter-specific competition. There were also significant relationships between the inter-specific competition index and the dominance index and the number of species at a site. In terms of intra-specific competition only ten of the 31 sites tested revealed a significant correlation between nearest-neighbour distance and summed canopy volume of the two neighbours. Seven were for Acacia species (55.6% of the Acacia species comparisons) and three were for broad-leaved species (21.4% of the broad-leaved species comparisons). Sites lacking evidence of intra-specific competition were at a significantly lower slope position and had a smaller proportion of small stems. The lower prevalence of competition in South African savannas detected in this study using the same method as previous studies is discussed, and the appropriateness of nearest-neighbour analysis is examined.
- Full Text:
- Date Issued: 2002
New views on the Jurassic Clarens Formation: volcano-sedimentary interaction
- Holzforster, Frank, Holzforster, Heike W, Marsh, Julian S
- Authors: Holzforster, Frank , Holzforster, Heike W , Marsh, Julian S
- Date: 2002
- Language: English
- Type: text , abstract
- Identifier: http://hdl.handle.net/10962/132716 , vital:36874
- Description: The Lower Jurassic Clarens Formation of the Great Karoo Basin is usually viewed in the literature as a aeolian and, in places, fluvio-aeolian deposit of tremendous thickness variation form 0-250 m thickness. Interaction with the overlying Karoo Flood Basalts, particularly in the Eastern Cape area and in Lesotho, has been noted but was never a major topic. Relatively widespread pyroclastic deposits sandwiched between the Clarens Formation and the Karoo Flood Basalts have been interpreted as flood-lahars.
- Full Text:
- Date Issued: 2002
- Authors: Holzforster, Frank , Holzforster, Heike W , Marsh, Julian S
- Date: 2002
- Language: English
- Type: text , abstract
- Identifier: http://hdl.handle.net/10962/132716 , vital:36874
- Description: The Lower Jurassic Clarens Formation of the Great Karoo Basin is usually viewed in the literature as a aeolian and, in places, fluvio-aeolian deposit of tremendous thickness variation form 0-250 m thickness. Interaction with the overlying Karoo Flood Basalts, particularly in the Eastern Cape area and in Lesotho, has been noted but was never a major topic. Relatively widespread pyroclastic deposits sandwiched between the Clarens Formation and the Karoo Flood Basalts have been interpreted as flood-lahars.
- Full Text:
- Date Issued: 2002
Non-governmental organizations, the state and the politics of rural development in Kenya with particular reference to Western Province
- Authors: Matanga, Frank Khachina
- Date: 2002
- Subjects: Non-governmental organizations -- Kenya , Rural development -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2803 , http://hdl.handle.net/10962/d1003013 , Non-governmental organizations -- Kenya , Rural development -- Kenya
- Description: In recent decades, Non-Governmental Organizations (NGOs) have increasingly taken on development and political roles in Africa. This has partly been attributed to the New Policy Agenda (NPA) mounted by the international donors. The NPA is predicated on neo-liberal thinking advocating for an enlarged development role for the private sector and a minimalist state. This relatively new shift in development thought has been motivated by the declining capacity of the African state to deliver development and guarantee a liberal political system. This study, therefore, set out to empirically examine whether NGOs are capable of effectively playing their new-found development and political roles. The study was based on Kenya with the Western Province constituting the core research area. The fact that the Kenyan state has been gradually disengaging from the development process has created a vacuum of which the NGOs have attempted to fill. Equally important has been the observation that, for the greater part of the post-colonial period, the state has been largely authoritarian and therefore prompting a segment of civil society to take on political roles in an effort to force it to liberalize and democratize. Urban NGOs in particular, have been the most confrontational to the state with some remarkable success. Unlike their urban counterparts, rural-based NGOs have tended to be more developmental and play a politics of collaboration with the state. Many of the latter NGOs, although playing a significant role in rural development, have been co-opted into patron-client networks. Factors that influence NGOs= posture towards the state include the nature of their leadership, the extent of their nternational connections, and the level of resources at their disposal. The study=s principal conclusion, is that, in as much as NGOs and overall civil society have provided a basis for development and opposition to the state, there is an urgent and growing need for them to shift from a position of dependency, whether domestic or international, to relative autonomy. Only then, will their contributions be sustainable in society.
- Full Text:
- Date Issued: 2002
- Authors: Matanga, Frank Khachina
- Date: 2002
- Subjects: Non-governmental organizations -- Kenya , Rural development -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2803 , http://hdl.handle.net/10962/d1003013 , Non-governmental organizations -- Kenya , Rural development -- Kenya
- Description: In recent decades, Non-Governmental Organizations (NGOs) have increasingly taken on development and political roles in Africa. This has partly been attributed to the New Policy Agenda (NPA) mounted by the international donors. The NPA is predicated on neo-liberal thinking advocating for an enlarged development role for the private sector and a minimalist state. This relatively new shift in development thought has been motivated by the declining capacity of the African state to deliver development and guarantee a liberal political system. This study, therefore, set out to empirically examine whether NGOs are capable of effectively playing their new-found development and political roles. The study was based on Kenya with the Western Province constituting the core research area. The fact that the Kenyan state has been gradually disengaging from the development process has created a vacuum of which the NGOs have attempted to fill. Equally important has been the observation that, for the greater part of the post-colonial period, the state has been largely authoritarian and therefore prompting a segment of civil society to take on political roles in an effort to force it to liberalize and democratize. Urban NGOs in particular, have been the most confrontational to the state with some remarkable success. Unlike their urban counterparts, rural-based NGOs have tended to be more developmental and play a politics of collaboration with the state. Many of the latter NGOs, although playing a significant role in rural development, have been co-opted into patron-client networks. Factors that influence NGOs= posture towards the state include the nature of their leadership, the extent of their nternational connections, and the level of resources at their disposal. The study=s principal conclusion, is that, in as much as NGOs and overall civil society have provided a basis for development and opposition to the state, there is an urgent and growing need for them to shift from a position of dependency, whether domestic or international, to relative autonomy. Only then, will their contributions be sustainable in society.
- Full Text:
- Date Issued: 2002
Nutrient digestibility in South African abalone (Haliotis Midae L.)
- Authors: Sales, James
- Date: 2002
- Subjects: Abalones -- Digestion Abalones -- Nutrition
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5305 , http://hdl.handle.net/10962/d1005150
- Description: The evaluation of potential alternative protein sources for the formulation of least-cost optimal diets to satisfy the nutrient requirements of South African abalone (Haliotis midae) has been hampered by the absence of a suitable, practical, replicable and reliable digestibility technique. A suitable lowcost faeces collection technique was developed in this study to obtain suitable quantities of excreta for analysis from this species. Acid-insoluble ash was identified as a reliable, replicable and safe internal marker in comparison to chromic oxide and crude fibre for use in nutrient digestibility studies with H. midae. This was validated by the consistency and repeatability of the results and by comparison to total collection of faeces. The traditional substitution method used in digestibility studies with fish to evaluate protein digestibility of feed ingredients was found to be unsuitable for H. midae. Apparent protein digestibility values exceeding 100 % derived through this method could be attributed to associative effects between feed ingredients, differential diet and faecal nutrient leaching, and mathematical artifacts in calculations when using substitution versus single protein diets. An ingredient particle size of less than 450 μm in comparison to particle size classes of above 450 μm was shown to enhance nutrient (dry matter, organic matter, protein, fat) digestibility and minimise dry matter leaching from diets. The dietary inclusion level of both pre-gelatinised maize starch and a-cellulose did not influence (P > 0.05) apparent nutrient (protein, fat, fiber, starch) digestibility. Using the above digestibility protocol amino acid availability of all plants ingredients currently used in the South African animal industry was evaluated for H. midae. Soybean meal (96.86 %) and lupins (96.51 %) presented the highest apparent mean amino acid availability of all plant protein ingredients evaluated with H. midae. Canola meal (94.21 %), faba beans (92.87 %) sunflower meal (92.77 %), peanut meal (87.39 %) and cottonseed meal (85.15 %) presented higher apparent mean amino acid availability values than fish meal (82.75 %). Apparent protein digestibility was highly correlated (r = 0.99) with mean apparent amino acid availability, while true amino acid availability was 1.88 % units higher than apparent amino acid availability for all ingredients tested. Predicted apparent protein digestibility in compound diets was within 1.1-6.5 % of determined values. Calcium phosphate mono dibasic presented the lowest (P < 0.05) dietary phosphorus leaching (51.51 % maximum) and highest apparent phosphorus digestibility (66.27 %) in comparison to other inorganic phosphorus sources. Based on the method of direct experimentation to determine the optimal dietary protein level using graded levels of dietary protein 28.1-35.9 % dietary protein from good quality sources is recommended for maximum growth of juvenile H. midae. This study provides a scientifically sound research tool including a faecal collection technique, suitable marker and assay technique that could be use in further studies to improve least-cost diet formulation for H. midae. Future nutritional studies in H. midae should primarily concentrate on reducing dietary nutrient leaching and improving the intake of nutrients in order to properly evaluate responses of this species to different dietary regimes.
- Full Text:
- Date Issued: 2002
- Authors: Sales, James
- Date: 2002
- Subjects: Abalones -- Digestion Abalones -- Nutrition
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5305 , http://hdl.handle.net/10962/d1005150
- Description: The evaluation of potential alternative protein sources for the formulation of least-cost optimal diets to satisfy the nutrient requirements of South African abalone (Haliotis midae) has been hampered by the absence of a suitable, practical, replicable and reliable digestibility technique. A suitable lowcost faeces collection technique was developed in this study to obtain suitable quantities of excreta for analysis from this species. Acid-insoluble ash was identified as a reliable, replicable and safe internal marker in comparison to chromic oxide and crude fibre for use in nutrient digestibility studies with H. midae. This was validated by the consistency and repeatability of the results and by comparison to total collection of faeces. The traditional substitution method used in digestibility studies with fish to evaluate protein digestibility of feed ingredients was found to be unsuitable for H. midae. Apparent protein digestibility values exceeding 100 % derived through this method could be attributed to associative effects between feed ingredients, differential diet and faecal nutrient leaching, and mathematical artifacts in calculations when using substitution versus single protein diets. An ingredient particle size of less than 450 μm in comparison to particle size classes of above 450 μm was shown to enhance nutrient (dry matter, organic matter, protein, fat) digestibility and minimise dry matter leaching from diets. The dietary inclusion level of both pre-gelatinised maize starch and a-cellulose did not influence (P > 0.05) apparent nutrient (protein, fat, fiber, starch) digestibility. Using the above digestibility protocol amino acid availability of all plants ingredients currently used in the South African animal industry was evaluated for H. midae. Soybean meal (96.86 %) and lupins (96.51 %) presented the highest apparent mean amino acid availability of all plant protein ingredients evaluated with H. midae. Canola meal (94.21 %), faba beans (92.87 %) sunflower meal (92.77 %), peanut meal (87.39 %) and cottonseed meal (85.15 %) presented higher apparent mean amino acid availability values than fish meal (82.75 %). Apparent protein digestibility was highly correlated (r = 0.99) with mean apparent amino acid availability, while true amino acid availability was 1.88 % units higher than apparent amino acid availability for all ingredients tested. Predicted apparent protein digestibility in compound diets was within 1.1-6.5 % of determined values. Calcium phosphate mono dibasic presented the lowest (P < 0.05) dietary phosphorus leaching (51.51 % maximum) and highest apparent phosphorus digestibility (66.27 %) in comparison to other inorganic phosphorus sources. Based on the method of direct experimentation to determine the optimal dietary protein level using graded levels of dietary protein 28.1-35.9 % dietary protein from good quality sources is recommended for maximum growth of juvenile H. midae. This study provides a scientifically sound research tool including a faecal collection technique, suitable marker and assay technique that could be use in further studies to improve least-cost diet formulation for H. midae. Future nutritional studies in H. midae should primarily concentrate on reducing dietary nutrient leaching and improving the intake of nutrients in order to properly evaluate responses of this species to different dietary regimes.
- Full Text:
- Date Issued: 2002
Open source in South African schools : two case studies
- Halse, Guy A, Terzoli, Alfredo
- Authors: Halse, Guy A , Terzoli, Alfredo
- Date: 2002
- Subjects: Open source
- Language: English
- Type: Conference paper
- Identifier: vital:6601 , http://hdl.handle.net/10962/d1009321
- Description: One of the major problems facing schools in South Africa is the difficulty in obtaining modern, up-to-date computer facilities. This paper looks at the use of open source solutions in two government schools in South Africa to demonstrate that it is possible for schools to utilise almost any existing computer to provide effective network solutions.
- Full Text:
- Date Issued: 2002
- Authors: Halse, Guy A , Terzoli, Alfredo
- Date: 2002
- Subjects: Open source
- Language: English
- Type: Conference paper
- Identifier: vital:6601 , http://hdl.handle.net/10962/d1009321
- Description: One of the major problems facing schools in South Africa is the difficulty in obtaining modern, up-to-date computer facilities. This paper looks at the use of open source solutions in two government schools in South Africa to demonstrate that it is possible for schools to utilise almost any existing computer to provide effective network solutions.
- Full Text:
- Date Issued: 2002
Open source in South African schools : two case studies
- Halse, G A, Terzoli, Alfredo
- Authors: Halse, G A , Terzoli, Alfredo
- Date: 2002
- Language: English
- Type: Conference paper
- Identifier: vital:6089 , http://hdl.handle.net/10962/d1009742
- Description: One of the major problems facing schools in South Africa is the difficulty in obtaining modern, up-to-date computer facilities. This paper looks at the use of open source solutions in two government schools in South Africa to demonstrate that it is possible for schools to utilise almost any existing computer to provide effective network solutions.
- Full Text:
- Date Issued: 2002
- Authors: Halse, G A , Terzoli, Alfredo
- Date: 2002
- Language: English
- Type: Conference paper
- Identifier: vital:6089 , http://hdl.handle.net/10962/d1009742
- Description: One of the major problems facing schools in South Africa is the difficulty in obtaining modern, up-to-date computer facilities. This paper looks at the use of open source solutions in two government schools in South Africa to demonstrate that it is possible for schools to utilise almost any existing computer to provide effective network solutions.
- Full Text:
- Date Issued: 2002
Parasitic Cape bees in the northern regions of South Africa: source of the founder population
- Neumann, Peter, Radloff, Sarah E, Hepburn, H Randall
- Authors: Neumann, Peter , Radloff, Sarah E , Hepburn, H Randall
- Date: 2002
- Language: English
- Type: text , Article
- Identifier: vital:6908 , http://hdl.handle.net/10962/d1011861
- Description: Multivariate discriminant analyses of nine standard morphometric characters of honeybee workers were used to track the origin of a social parasitic pseudo-clone of thelytokous laying workers that have invaded colonies of Apis mellifera scutellata in South Africa. Twenty social parasitic workers were sampled from both of two infested A. m. scutellata colonies at two distant apiaries (Graskop and Heilbronn, about 390 km apart) and compared with data obtained from 80 colonies in four different geographical zones (zone I: thelytokous A. m. capensis morphocluster; zone II: natural thelytokous hybrids between A. m. capensis and A. m. scutellata; zone III: thelytokous A. m. scutellata morphocluster; zone IV: an arrhenotokous A. m. scutellata morphocluster). Thelytokous laying workers occur naturally in zones I-III. Highly significant morphometric differences were found among the bees in the four zones. The data support the conclusion that the social parasitic workers belong to the thelytokous A. m. capensis morphocluster. It is most likely that the social parasitic workers originated from the heart of the Cape bee's distribution range in the Western Cape region in zone I. Morphometric analysis makes it feasible to restrict the possible origin of the social parasitic workers from the natural distribution range of thelytoky (approximately 240 000 km2) down to about 12 000 km2, which represents a resolution capacity of about 95%.
- Full Text:
- Date Issued: 2002
- Authors: Neumann, Peter , Radloff, Sarah E , Hepburn, H Randall
- Date: 2002
- Language: English
- Type: text , Article
- Identifier: vital:6908 , http://hdl.handle.net/10962/d1011861
- Description: Multivariate discriminant analyses of nine standard morphometric characters of honeybee workers were used to track the origin of a social parasitic pseudo-clone of thelytokous laying workers that have invaded colonies of Apis mellifera scutellata in South Africa. Twenty social parasitic workers were sampled from both of two infested A. m. scutellata colonies at two distant apiaries (Graskop and Heilbronn, about 390 km apart) and compared with data obtained from 80 colonies in four different geographical zones (zone I: thelytokous A. m. capensis morphocluster; zone II: natural thelytokous hybrids between A. m. capensis and A. m. scutellata; zone III: thelytokous A. m. scutellata morphocluster; zone IV: an arrhenotokous A. m. scutellata morphocluster). Thelytokous laying workers occur naturally in zones I-III. Highly significant morphometric differences were found among the bees in the four zones. The data support the conclusion that the social parasitic workers belong to the thelytokous A. m. capensis morphocluster. It is most likely that the social parasitic workers originated from the heart of the Cape bee's distribution range in the Western Cape region in zone I. Morphometric analysis makes it feasible to restrict the possible origin of the social parasitic workers from the natural distribution range of thelytoky (approximately 240 000 km2) down to about 12 000 km2, which represents a resolution capacity of about 95%.
- Full Text:
- Date Issued: 2002
Participation and dialogue in development
- Authors: Neves, David Telles
- Date: 2002
- Subjects: Action theory , Communication in economic development
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3148 , http://hdl.handle.net/10962/d1007456 , Action theory , Communication in economic development
- Description: "Participation" is a frequently articulated requirement within the context of community development. Yet despite this, the concept of participation is neither comprehensively theorised, nor entirely unproblematic. The theoretical paucity surrounding participation is particularly marked within accounts of its interactional and relational dynamics . This thesis is accordingly concerned with theorising the interactional and relational features of participation in, and for, development. To this end a small development intervention, constituted as an agricultural co-operative within a rural area of South Africa, is examined. In this inquiry the phenomenon of participation is viewed through the lens of dialogical-activity. This enables explication of the "joint activity" directed towards participatory development, within the focal research setting. The overarching theoretical framework for this thesis is conferred by Activity theory. Orientated towards examining the collective and artefactually mediated nature of human action, Activity theory is foregrounded in Y. Engeström's (1989; 1999b) analytic schema of the Activity System. This Activity System framework is expanded by the inclusion of communicative and semiotic elements; an inclusion effected by reference to R. Engeström's theory of communicative action (1995,1999), which in turn, draws on theoretical precepts gleaned from the work of Mikhail Bakhtin. The resultant fusing of dialogue and activity therefore serves to extend Activity theoretical insights. The results of this research are based on data collected from a multitude of sources within the focal participatory development research setting, including internal project documentation, interview transcripts and field notes. The dialogical Bakhtin-derived an alytic categories of speech genre , voice and social language were drawn on in order to examine this textual data , and to explicate the interactional and relational features of participatory development. Analysis of these served to reveal the polyphony of (speech genre constituted) voices, wherein the phenomenon of participation is disparately accentuated. The results chapter moreover discusses the substantial mismatches and discontinuities in the referential object invoked by the various roleplayers, within the focal research context. This thesis considers the sources of these discontinuities and tensions, including how they point to historically constituted contradictions within participatory development. It furthermore briefly examines the opportunities and affordances these offer up for expansive new forms of activity. Finally, in re-examining participation and development, the complex, and sometimes antithetic relationship that exists between these two concepts and their associated social practices, are considered.
- Full Text:
- Date Issued: 2002
- Authors: Neves, David Telles
- Date: 2002
- Subjects: Action theory , Communication in economic development
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3148 , http://hdl.handle.net/10962/d1007456 , Action theory , Communication in economic development
- Description: "Participation" is a frequently articulated requirement within the context of community development. Yet despite this, the concept of participation is neither comprehensively theorised, nor entirely unproblematic. The theoretical paucity surrounding participation is particularly marked within accounts of its interactional and relational dynamics . This thesis is accordingly concerned with theorising the interactional and relational features of participation in, and for, development. To this end a small development intervention, constituted as an agricultural co-operative within a rural area of South Africa, is examined. In this inquiry the phenomenon of participation is viewed through the lens of dialogical-activity. This enables explication of the "joint activity" directed towards participatory development, within the focal research setting. The overarching theoretical framework for this thesis is conferred by Activity theory. Orientated towards examining the collective and artefactually mediated nature of human action, Activity theory is foregrounded in Y. Engeström's (1989; 1999b) analytic schema of the Activity System. This Activity System framework is expanded by the inclusion of communicative and semiotic elements; an inclusion effected by reference to R. Engeström's theory of communicative action (1995,1999), which in turn, draws on theoretical precepts gleaned from the work of Mikhail Bakhtin. The resultant fusing of dialogue and activity therefore serves to extend Activity theoretical insights. The results of this research are based on data collected from a multitude of sources within the focal participatory development research setting, including internal project documentation, interview transcripts and field notes. The dialogical Bakhtin-derived an alytic categories of speech genre , voice and social language were drawn on in order to examine this textual data , and to explicate the interactional and relational features of participatory development. Analysis of these served to reveal the polyphony of (speech genre constituted) voices, wherein the phenomenon of participation is disparately accentuated. The results chapter moreover discusses the substantial mismatches and discontinuities in the referential object invoked by the various roleplayers, within the focal research context. This thesis considers the sources of these discontinuities and tensions, including how they point to historically constituted contradictions within participatory development. It furthermore briefly examines the opportunities and affordances these offer up for expansive new forms of activity. Finally, in re-examining participation and development, the complex, and sometimes antithetic relationship that exists between these two concepts and their associated social practices, are considered.
- Full Text:
- Date Issued: 2002
Permaculture as an aspect of environmental learning: an investigation into secondary school communities in Zimbabwe
- Authors: Nyika, Mugove Walter
- Date: 2002
- Subjects: Permaculture -- Study and teaching (Secondary) -- Zimbabwe Land use -- Zimbabwe Land use -- Environmental aspects -- Zimbabwe Agriculture -- Zimbabwe Sustainable agriculture -- Zimbabawe
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1960 , http://hdl.handle.net/10962/d1008447
- Description: The Schools and Colleges Permaculture (SCOPE) Programme in Zimbabwe has developed a process for use by schools in planning for the sustainable management of their land. The process is called Integrated Land-Use Design (ILUD) and is based on Permaculture principles. The ILUD process has so far been implemented in 54 pilot schools where it has been used to facilitate the re-design of the school grounds through the active participation of the students, staff and parents. The aim of this research was to investigate what environmental learning takes place during the implementation of the ILUD process and related activities, with a view to informing the improvement of the process. The research was conducted within the interpretive paradigm with particular use being made of the Symbolic Interactionist theoretical framework to explore the social situations in which the ILUD process has been applied. A purposive sample of two schools and five form 4 (grade 11) pupils from each school was selected for the study. The main data collection method was the structured interview. Other data were collected from nonparticipant observations and the analysis of documents, particularly photographs. The data was analysed using the constant comparative method. The findings point towards a significant contribution from the Permaculture activities to the environmental knowledge, environmental management skills and the positive environmental attitudes of the pupils. The work done at the two schools indicates the usefulness of the ILUD process as a tool for environmental action in the schools but its application in the communities was found to be limited by constraints such as lack of resources and the limited capacity of teachers to work in the field of adult education and training. It is recommended that Permaculture should be integrated into the secondary school curriculum if the momentum of the progress made so far is to be maintained. The SCOPE Programme itself needs to be strengthened for its work with communities. There is, for example, a need for adult education and training methods if the introduction of ILUD to the communities is to be successful.
- Full Text:
- Date Issued: 2002
- Authors: Nyika, Mugove Walter
- Date: 2002
- Subjects: Permaculture -- Study and teaching (Secondary) -- Zimbabwe Land use -- Zimbabwe Land use -- Environmental aspects -- Zimbabwe Agriculture -- Zimbabwe Sustainable agriculture -- Zimbabawe
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1960 , http://hdl.handle.net/10962/d1008447
- Description: The Schools and Colleges Permaculture (SCOPE) Programme in Zimbabwe has developed a process for use by schools in planning for the sustainable management of their land. The process is called Integrated Land-Use Design (ILUD) and is based on Permaculture principles. The ILUD process has so far been implemented in 54 pilot schools where it has been used to facilitate the re-design of the school grounds through the active participation of the students, staff and parents. The aim of this research was to investigate what environmental learning takes place during the implementation of the ILUD process and related activities, with a view to informing the improvement of the process. The research was conducted within the interpretive paradigm with particular use being made of the Symbolic Interactionist theoretical framework to explore the social situations in which the ILUD process has been applied. A purposive sample of two schools and five form 4 (grade 11) pupils from each school was selected for the study. The main data collection method was the structured interview. Other data were collected from nonparticipant observations and the analysis of documents, particularly photographs. The data was analysed using the constant comparative method. The findings point towards a significant contribution from the Permaculture activities to the environmental knowledge, environmental management skills and the positive environmental attitudes of the pupils. The work done at the two schools indicates the usefulness of the ILUD process as a tool for environmental action in the schools but its application in the communities was found to be limited by constraints such as lack of resources and the limited capacity of teachers to work in the field of adult education and training. It is recommended that Permaculture should be integrated into the secondary school curriculum if the momentum of the progress made so far is to be maintained. The SCOPE Programme itself needs to be strengthened for its work with communities. There is, for example, a need for adult education and training methods if the introduction of ILUD to the communities is to be successful.
- Full Text:
- Date Issued: 2002
pH study of the electrocatalytic SO2 detection at a glassy carbon electrode modified with iron (II) tetrasulfophthalocyanine
- Thamae, Mamothibe, Westbroek, Philippe, Nyokong, Tebello
- Authors: Thamae, Mamothibe , Westbroek, Philippe , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304786 , vital:58490 , xlink:href="https://doi.org/10.1007/s00604-002-0914-8"
- Description: The electrocatalytic determination of SO2 is studied as a function of pH at a glassy carbon electrode modified with iron(II)tetrasulfophthalocyanine ([Fe(II)TSPc]4−). It was found in the literature that depending on pH, SO2·xH2O, HSO3 − and/or SO3 2− are the main compounds in solution, that these compounds behave differently at the electrode surface, and that the condition of the electrode surface is stable over the entire pH-range. The use of SO2(g) or sodium sulfite as starting material did result in identical curves except in the pH range from 7.5–9.0. A possible explanation could be given by proposing that SO2·xH2O is very unstable in the presence of SO3 2−. In strongly acidic medium, SO2·xH2O is the main compound, which can be oxidized as well as reduced with exchange of two electrons. HSO3 − is the main compound at pH = 4 and can also be oxidized and reduced with exchange of, respectively, two and four electrons. In alkaline solution sulfite is the main compound and can only be oxidized, also under exchange of two electrons. Detection limits are in the range of 4.0 ± 0.1 × 10−5 and 7.5 ± 0.1 × 10−5 mol L−1, dependent of pH and of the type of reaction (oxidation or reduction) used.
- Full Text:
- Date Issued: 2002
- Authors: Thamae, Mamothibe , Westbroek, Philippe , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/304786 , vital:58490 , xlink:href="https://doi.org/10.1007/s00604-002-0914-8"
- Description: The electrocatalytic determination of SO2 is studied as a function of pH at a glassy carbon electrode modified with iron(II)tetrasulfophthalocyanine ([Fe(II)TSPc]4−). It was found in the literature that depending on pH, SO2·xH2O, HSO3 − and/or SO3 2− are the main compounds in solution, that these compounds behave differently at the electrode surface, and that the condition of the electrode surface is stable over the entire pH-range. The use of SO2(g) or sodium sulfite as starting material did result in identical curves except in the pH range from 7.5–9.0. A possible explanation could be given by proposing that SO2·xH2O is very unstable in the presence of SO3 2−. In strongly acidic medium, SO2·xH2O is the main compound, which can be oxidized as well as reduced with exchange of two electrons. HSO3 − is the main compound at pH = 4 and can also be oxidized and reduced with exchange of, respectively, two and four electrons. In alkaline solution sulfite is the main compound and can only be oxidized, also under exchange of two electrons. Detection limits are in the range of 4.0 ± 0.1 × 10−5 and 7.5 ± 0.1 × 10−5 mol L−1, dependent of pH and of the type of reaction (oxidation or reduction) used.
- Full Text:
- Date Issued: 2002
Physical and biological variability in the Antarctic Polar Frontal Zone: report on research cruise 103 of the MV SA Agulhas
- Froneman, P William, Ansorge, Isabelle J, Vumazonke, Lukhanyiso U, Gulekana, A, Bernard, K S, Webb, Arthur C M, Leukes, W, Risien, C M, Thomalla, S, Hermes, J, Knott, M, Anderson, D, Hargey, N, Jennings, M E, Veitch, J, Lutjeharms, Johan R E, McQuaid, Christopher D
- Authors: Froneman, P William , Ansorge, Isabelle J , Vumazonke, Lukhanyiso U , Gulekana, A , Bernard, K S , Webb, Arthur C M , Leukes, W , Risien, C M , Thomalla, S , Hermes, J , Knott, M , Anderson, D , Hargey, N , Jennings, M E , Veitch, J , Lutjeharms, Johan R E , McQuaid, Christopher D
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6910 , http://hdl.handle.net/10962/d1011863
- Description: A detailed hydrographic and biological survey was carried out in the region of the South-west Indian Ridge during April 2002. Hydrographic data revealed that the Andrew Bain Fracture Zone, centred at 30oE, 50oS, functions as an important choke point to the flow of the Antarctic Circumpolar Current, resulting in the convergence of the Antarctic Polar Front (APF) and the southern branch of the Sub-Antarctic Front (SSAF). Total chlorophyll-a concentration and zooplankton biomass were highest at stations occupied in the vicinity of two frontal features represented by the APF and SSAF. These data suggest that the region of the South-west Indian Ridge is an area of elevated biological activity and probably acts as an important offshore feeding area for the top predators on the Prince Edward Islands.
- Full Text:
- Date Issued: 2002
- Authors: Froneman, P William , Ansorge, Isabelle J , Vumazonke, Lukhanyiso U , Gulekana, A , Bernard, K S , Webb, Arthur C M , Leukes, W , Risien, C M , Thomalla, S , Hermes, J , Knott, M , Anderson, D , Hargey, N , Jennings, M E , Veitch, J , Lutjeharms, Johan R E , McQuaid, Christopher D
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6910 , http://hdl.handle.net/10962/d1011863
- Description: A detailed hydrographic and biological survey was carried out in the region of the South-west Indian Ridge during April 2002. Hydrographic data revealed that the Andrew Bain Fracture Zone, centred at 30oE, 50oS, functions as an important choke point to the flow of the Antarctic Circumpolar Current, resulting in the convergence of the Antarctic Polar Front (APF) and the southern branch of the Sub-Antarctic Front (SSAF). Total chlorophyll-a concentration and zooplankton biomass were highest at stations occupied in the vicinity of two frontal features represented by the APF and SSAF. These data suggest that the region of the South-west Indian Ridge is an area of elevated biological activity and probably acts as an important offshore feeding area for the top predators on the Prince Edward Islands.
- Full Text:
- Date Issued: 2002
Physiological and perceptual responses of SANDF personnel to varying combinations of marching speed and backpack load
- Authors: Christie, Candice Jo-Anne
- Date: 2002
- Subjects: Marching -- Physiological aspects , Walking -- Physiological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5128 , http://hdl.handle.net/10962/d1005207 , Marching -- Physiological aspects , Walking -- Physiological aspects
- Description: The objective of the present study was to establish effective combinations of marching speed and backpack load in order to meet specific military requirements. Thirty infantrymen from the South African National Defence Force (SANDF) comprised the sample and experimental procedures were conducted in a laboratory setting using a Cybex Trotter treadmill. Sixteen conditions were set up which included combinations of four speeds (3.5, 4.5, 5.5, and 6.5 km.h⁻¹) and four backpack loads (20, 35, 50, and 65kg). Each subject was required to complete 8 of the sixteen conditions, each consisting of a six-minute treadmill march. Physiological data (heart rate, ventilation and metabolic responses), kinematic gait responses (step-rate and stride length) and perceptions of exertion (“Central” and “Local” RPE) were collected during the third and sixth minutes of the treadmill march and areas of body discomfort were identified post-march. Responses revealed five distinct categories of exertional strain. Three marches constituted “nominal” (below 40% VO₂max) and three “excessive” strain (above 75% VO₂ max). These represent combinations of extreme military demands and are highly unlikely to be utilised by the military. Three “tolerable” levels of required effort were recommended and these 10 combinations were further divided into three sub-categories. The “moderate” stress marches were identified as “ideal” for prolonged marches and had statistically similar responses of working heart rates (range of 118 bt.min⁻¹ to 127 bt.min⁻¹), energy expenditure (26 kJ.min⁻¹ and 27 kJ.min⁻¹) and ratings of perceived exertion (“Central” ratings of 10 and 11). Thus, marching at 5.5 km.h⁻¹with 20kg, 4.5 km.h⁻¹ with 35kg or 3.5 km.h⁻¹ with 50kg all require a similar energy cost. Four “heavy” category marches were identified for possible use when the duration of the march is reduced. During these marches responses were statistically similar with heart rates ranging from 127 bt.min⁻¹ to 137 bt.min⁻¹, energy expenditure from 32 kJ.min⁻¹ to 37 kJ.min⁻¹ and “Central” ratings of perceived exertion were 12 and 13. When short, high intensity marches are necessary, then combinations from the “very heavy” category may be utilised but with caution. During these marches, soldiers were taxed between 65% and 75% of VO2 max. The results of this study clearly demonstrate that the interplay between speed and load needs to be adjusted when determining “ideal” combinations for specific military demands. Essentially, if speed is of the essence then load must be reduced, and if heavy loads need to be transported then speed must be reduced.
- Full Text:
- Date Issued: 2002
- Authors: Christie, Candice Jo-Anne
- Date: 2002
- Subjects: Marching -- Physiological aspects , Walking -- Physiological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5128 , http://hdl.handle.net/10962/d1005207 , Marching -- Physiological aspects , Walking -- Physiological aspects
- Description: The objective of the present study was to establish effective combinations of marching speed and backpack load in order to meet specific military requirements. Thirty infantrymen from the South African National Defence Force (SANDF) comprised the sample and experimental procedures were conducted in a laboratory setting using a Cybex Trotter treadmill. Sixteen conditions were set up which included combinations of four speeds (3.5, 4.5, 5.5, and 6.5 km.h⁻¹) and four backpack loads (20, 35, 50, and 65kg). Each subject was required to complete 8 of the sixteen conditions, each consisting of a six-minute treadmill march. Physiological data (heart rate, ventilation and metabolic responses), kinematic gait responses (step-rate and stride length) and perceptions of exertion (“Central” and “Local” RPE) were collected during the third and sixth minutes of the treadmill march and areas of body discomfort were identified post-march. Responses revealed five distinct categories of exertional strain. Three marches constituted “nominal” (below 40% VO₂max) and three “excessive” strain (above 75% VO₂ max). These represent combinations of extreme military demands and are highly unlikely to be utilised by the military. Three “tolerable” levels of required effort were recommended and these 10 combinations were further divided into three sub-categories. The “moderate” stress marches were identified as “ideal” for prolonged marches and had statistically similar responses of working heart rates (range of 118 bt.min⁻¹ to 127 bt.min⁻¹), energy expenditure (26 kJ.min⁻¹ and 27 kJ.min⁻¹) and ratings of perceived exertion (“Central” ratings of 10 and 11). Thus, marching at 5.5 km.h⁻¹with 20kg, 4.5 km.h⁻¹ with 35kg or 3.5 km.h⁻¹ with 50kg all require a similar energy cost. Four “heavy” category marches were identified for possible use when the duration of the march is reduced. During these marches responses were statistically similar with heart rates ranging from 127 bt.min⁻¹ to 137 bt.min⁻¹, energy expenditure from 32 kJ.min⁻¹ to 37 kJ.min⁻¹ and “Central” ratings of perceived exertion were 12 and 13. When short, high intensity marches are necessary, then combinations from the “very heavy” category may be utilised but with caution. During these marches, soldiers were taxed between 65% and 75% of VO2 max. The results of this study clearly demonstrate that the interplay between speed and load needs to be adjusted when determining “ideal” combinations for specific military demands. Essentially, if speed is of the essence then load must be reduced, and if heavy loads need to be transported then speed must be reduced.
- Full Text:
- Date Issued: 2002
Physiological and psychophysical responses of male soldiers to changes in marching gradient, speed and load
- Authors: Todd, Andrew Ivan
- Date: 2002
- Subjects: Soldiers -- South Africa -- Physiology , South Africa Army -- Physical training , Marching -- Physiological aspects , Psychophysiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5129 , http://hdl.handle.net/10962/d1005208 , Soldiers -- South Africa -- Physiology , South Africa Army -- Physical training , Marching -- Physiological aspects , Psychophysiology
- Description: The present study sought to investigate the effects of changes in gradient, under apparently optimal combinations of speed and load, on selected physiological, psychophysical and biophysical responses of military personnel. Subjects (n = 32) were required to march under level (0%), downhill (-10%) and uphill (+10%) conditions. Under each gradient, subjects marched with the following speed-load combinations: 4 km.h-1 carrying 50 kg, 5 km.h-1 carrying 35 kg and 6 km.h-1 carrying 20 kg, a total of nine experimental conditions. Subjects were required to march for six minutes under each condition. Physiological responses (HR, VO2, R, Br, VE, VT, EE) indicated that subjects were not overly taxed by the three speed-load combinations during level marching, which elicited submaximal demands. Furthermore, the results revealed that downhill marching with heavy loads results in similar responses to level marching, while lighter loads may result in significant reductions in physical demands compared to level marching. The physiological responses to uphill marching revealed that subjects were severely physically taxed under these conditions, regardless of speed-load combination. It is unlikely that soldiers would be able to maintain these intensities for an extended period without undue fatigue. It is evident from the psychophysical responses (Rating of Perceived Exertion and Body Discomfort) that subjects perceived the heavy load conditions, regardless of gradient, to be the most stressful on the cardiovascular and muscular systems. The positive gradient conditions also elicited elevated RPE and Body Discomfort responses, while lighter load downhill conditions were perceived to result in the least strain.
- Full Text:
- Date Issued: 2002
- Authors: Todd, Andrew Ivan
- Date: 2002
- Subjects: Soldiers -- South Africa -- Physiology , South Africa Army -- Physical training , Marching -- Physiological aspects , Psychophysiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5129 , http://hdl.handle.net/10962/d1005208 , Soldiers -- South Africa -- Physiology , South Africa Army -- Physical training , Marching -- Physiological aspects , Psychophysiology
- Description: The present study sought to investigate the effects of changes in gradient, under apparently optimal combinations of speed and load, on selected physiological, psychophysical and biophysical responses of military personnel. Subjects (n = 32) were required to march under level (0%), downhill (-10%) and uphill (+10%) conditions. Under each gradient, subjects marched with the following speed-load combinations: 4 km.h-1 carrying 50 kg, 5 km.h-1 carrying 35 kg and 6 km.h-1 carrying 20 kg, a total of nine experimental conditions. Subjects were required to march for six minutes under each condition. Physiological responses (HR, VO2, R, Br, VE, VT, EE) indicated that subjects were not overly taxed by the three speed-load combinations during level marching, which elicited submaximal demands. Furthermore, the results revealed that downhill marching with heavy loads results in similar responses to level marching, while lighter loads may result in significant reductions in physical demands compared to level marching. The physiological responses to uphill marching revealed that subjects were severely physically taxed under these conditions, regardless of speed-load combination. It is unlikely that soldiers would be able to maintain these intensities for an extended period without undue fatigue. It is evident from the psychophysical responses (Rating of Perceived Exertion and Body Discomfort) that subjects perceived the heavy load conditions, regardless of gradient, to be the most stressful on the cardiovascular and muscular systems. The positive gradient conditions also elicited elevated RPE and Body Discomfort responses, while lighter load downhill conditions were perceived to result in the least strain.
- Full Text:
- Date Issued: 2002
Policy and practice : an activity systems' analysis of a further diploma in education (technology)
- Thomen, Eva Christine Salzmann
- Authors: Thomen, Eva Christine Salzmann
- Date: 2002
- Subjects: Action theory Teachers -- Training of -- South Africa Technology -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1854 , http://hdl.handle.net/10962/d1004525
- Description: This research examines, within the interpretive paradigm, how emerging educational policy in an in-service educator education programme, namely, a Further Diploma in Education (Technology), is implemented and practiced by educators in the classroom. Technology is a new learning area in the South African curriculum that aims to develop learners' technological skills and promote the practical application of Science and Mathematics. Technology is seen as a way of developing a productive workforce that can design, realise and evaluate technological problems in a global economy. Engestrom's version of Activity Theory was used as the conceptual framework. Activity Theory focuses on 'activity' as a unit of analysis that captures the individual in context. This research focuses on the lecturers' and the students' actions in the programme, and the educators' and the learners' actions in the classroom. The research design was an eclectic case study consisting of two embedded cases within a single larger case namely, in-service educator education. Multiple single cases were selected within the two embedded cases. Trustworthiness and authenticity were addressed through the triangulation of data using mUltiple sources and methods of data collection. Data were analysed and interpreted in a hermeneutic-like process that emerged through gradual induction over time. The findings of the research suggest that the in-service educator education programme did not promote the effective implementation of educational policy. Major challenges to the effective implementation of educational policy include: the formulation and implementation of an INSET programme during rapid educational policy change, the under-preparedness and language difficulties of the participating educators that constrained policy implementation in the INSET programme and the classroom, the role of organisational rules in shaping the activities in the INSET programme and the classroom, and the broader community'S contribution to resource constraints in the classroom. This research suggests that the participating educators are not likely to be major change agents in the transformation of education in South Africa. This concurs with other research findings that suggest that educator education is a weak intervention incapable of overcoming the shortcomings of the educators' own personal schooling or the impact of work experience.
- Full Text:
- Date Issued: 2002
- Authors: Thomen, Eva Christine Salzmann
- Date: 2002
- Subjects: Action theory Teachers -- Training of -- South Africa Technology -- Study and teaching -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:1854 , http://hdl.handle.net/10962/d1004525
- Description: This research examines, within the interpretive paradigm, how emerging educational policy in an in-service educator education programme, namely, a Further Diploma in Education (Technology), is implemented and practiced by educators in the classroom. Technology is a new learning area in the South African curriculum that aims to develop learners' technological skills and promote the practical application of Science and Mathematics. Technology is seen as a way of developing a productive workforce that can design, realise and evaluate technological problems in a global economy. Engestrom's version of Activity Theory was used as the conceptual framework. Activity Theory focuses on 'activity' as a unit of analysis that captures the individual in context. This research focuses on the lecturers' and the students' actions in the programme, and the educators' and the learners' actions in the classroom. The research design was an eclectic case study consisting of two embedded cases within a single larger case namely, in-service educator education. Multiple single cases were selected within the two embedded cases. Trustworthiness and authenticity were addressed through the triangulation of data using mUltiple sources and methods of data collection. Data were analysed and interpreted in a hermeneutic-like process that emerged through gradual induction over time. The findings of the research suggest that the in-service educator education programme did not promote the effective implementation of educational policy. Major challenges to the effective implementation of educational policy include: the formulation and implementation of an INSET programme during rapid educational policy change, the under-preparedness and language difficulties of the participating educators that constrained policy implementation in the INSET programme and the classroom, the role of organisational rules in shaping the activities in the INSET programme and the classroom, and the broader community'S contribution to resource constraints in the classroom. This research suggests that the participating educators are not likely to be major change agents in the transformation of education in South Africa. This concurs with other research findings that suggest that educator education is a weak intervention incapable of overcoming the shortcomings of the educators' own personal schooling or the impact of work experience.
- Full Text:
- Date Issued: 2002
Process for the preparation of vanillin from a mixed m-cresol/p-cresol stream
- Authors: Buddoo, Subash
- Date: 2002
- Subjects: Vanillin
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10968 , http://hdl.handle.net/10948/138 , Vanillin
- Description: The Vanillin project was undertaken by AECI as it was believed that with the raw materials available from SASOL i.e. cresols, it would be possible to develop a process that would be globally competitive. A process for preparing both vanillin and ethyl vanillin was developed by AECI’s Research and Development Department using a mixed m- and p-cresol stream as feed. The displacement of bromide by methoxide is very successful when using a dimethyl formamide (DMF)/alcohol solvent system and excellent conversions (>95%) and selectivities (>95%) may be obtained. However, the use of DMF, which poses a serious chronic health risk, is unacceptable in this process since the products are intended for use as food and flavouring chemicals. In view of the above the main objectives of this study were: · To find a suitable alternative solvent system, which could produce comparable results while still being economically viable; · To develop an appropriate experimental protocol in the laboratory based on the alternative solvent system; · To determine the important reaction variables by conducting statistically designed experiments; · To optimise the reaction to produce a reproducible and robust experimental protocol; and · To test the reaction thoroughly at bench-scale level and to obtain experimental data for scale-up to pilot plant The most promising alternative solvent system was a methanol/methyl acetate mixture, which produced satisfactory results in the preliminary assessment (conversion of 98.3% and selectivity of 92.0%). DMA and acetonitrile also produced promising results but were not considered for further investigation because of toxicity and cost issues. A set of statistically designed experiments was carried out on the methanol/methyl acetate solvent system where four variables were tested i.e., substrate concentration, temperature, catalyst loading, and methanol to methyl acetate volume ratio. The experimentally determined response surface model showed that the most important variable was catalyst loading (63.2%) for conversion. With respect to selectivity, the most important variables were catalyst loading (31.9%) and methanol to methyl acetate ratio (33.1%). The optimum reaction conditions were as follows: · Temperature: 120°C · Methanol:methyl acetate: 15:1 vol/vol · Catalyst loading: 8 mol % to substrate · Substrate concentration: 22 %m/m on solvent · Catalyst: Copper(I) bromide · Sodium Equivalents: 2.7 wrt substrate · Time: 3 hours The optimum conditions were tested for reproducibility in a 1 Labmax pressure reactor. Replicated reactions, two at a 10% and two at a 20% substrate concentration gave conversions and selectivities all greater than 90%. Although the reaction mixture was a slurry at these concentrations, the reactions were very fast and virtually complete within the first hour (~95% conversion). Initial scale-up studies were conducted in an 8 Parr reactor where five reactions were carried out using the optimum conditions described above. The conversion of substrate and vanillin selectivity was consistently high and compared favourably to the Labmax reactions. The average conversion was 97.3% (96.3 to 98.5%) at an average selectivity of 98.2% (97.4 to 99.1%). A study of the reaction kinetics confirmed that the reaction was first order with respect to the substrate as a plot of substrate concentration versus reaction rate gave a straight line. The rate constant was calculated as 1.1096 k(h-1). The reaction mechanism proposed for the copper assisted nucleophilic aromatic substitution involves the formation of an adduct between sodium methoxide, methyl acetate and copper(I) bromide. The formation of a transient intermediate with the substrate allows intramolecular delivery of the methoxide ion to the aryl moiety through a CuI – CuIII type cycle.
- Full Text:
- Date Issued: 2002
- Authors: Buddoo, Subash
- Date: 2002
- Subjects: Vanillin
- Language: English
- Type: Thesis , Masters , MTech (Chemistry)
- Identifier: vital:10968 , http://hdl.handle.net/10948/138 , Vanillin
- Description: The Vanillin project was undertaken by AECI as it was believed that with the raw materials available from SASOL i.e. cresols, it would be possible to develop a process that would be globally competitive. A process for preparing both vanillin and ethyl vanillin was developed by AECI’s Research and Development Department using a mixed m- and p-cresol stream as feed. The displacement of bromide by methoxide is very successful when using a dimethyl formamide (DMF)/alcohol solvent system and excellent conversions (>95%) and selectivities (>95%) may be obtained. However, the use of DMF, which poses a serious chronic health risk, is unacceptable in this process since the products are intended for use as food and flavouring chemicals. In view of the above the main objectives of this study were: · To find a suitable alternative solvent system, which could produce comparable results while still being economically viable; · To develop an appropriate experimental protocol in the laboratory based on the alternative solvent system; · To determine the important reaction variables by conducting statistically designed experiments; · To optimise the reaction to produce a reproducible and robust experimental protocol; and · To test the reaction thoroughly at bench-scale level and to obtain experimental data for scale-up to pilot plant The most promising alternative solvent system was a methanol/methyl acetate mixture, which produced satisfactory results in the preliminary assessment (conversion of 98.3% and selectivity of 92.0%). DMA and acetonitrile also produced promising results but were not considered for further investigation because of toxicity and cost issues. A set of statistically designed experiments was carried out on the methanol/methyl acetate solvent system where four variables were tested i.e., substrate concentration, temperature, catalyst loading, and methanol to methyl acetate volume ratio. The experimentally determined response surface model showed that the most important variable was catalyst loading (63.2%) for conversion. With respect to selectivity, the most important variables were catalyst loading (31.9%) and methanol to methyl acetate ratio (33.1%). The optimum reaction conditions were as follows: · Temperature: 120°C · Methanol:methyl acetate: 15:1 vol/vol · Catalyst loading: 8 mol % to substrate · Substrate concentration: 22 %m/m on solvent · Catalyst: Copper(I) bromide · Sodium Equivalents: 2.7 wrt substrate · Time: 3 hours The optimum conditions were tested for reproducibility in a 1 Labmax pressure reactor. Replicated reactions, two at a 10% and two at a 20% substrate concentration gave conversions and selectivities all greater than 90%. Although the reaction mixture was a slurry at these concentrations, the reactions were very fast and virtually complete within the first hour (~95% conversion). Initial scale-up studies were conducted in an 8 Parr reactor where five reactions were carried out using the optimum conditions described above. The conversion of substrate and vanillin selectivity was consistently high and compared favourably to the Labmax reactions. The average conversion was 97.3% (96.3 to 98.5%) at an average selectivity of 98.2% (97.4 to 99.1%). A study of the reaction kinetics confirmed that the reaction was first order with respect to the substrate as a plot of substrate concentration versus reaction rate gave a straight line. The rate constant was calculated as 1.1096 k(h-1). The reaction mechanism proposed for the copper assisted nucleophilic aromatic substitution involves the formation of an adduct between sodium methoxide, methyl acetate and copper(I) bromide. The formation of a transient intermediate with the substrate allows intramolecular delivery of the methoxide ion to the aryl moiety through a CuI – CuIII type cycle.
- Full Text:
- Date Issued: 2002
Processes of transformation in a group psychotherapy intervention for single mothers
- Authors: Spiro, Monica
- Date: 2002
- Subjects: Single mothers -- Psychological aspects Group psychotherapy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3100 , http://hdl.handle.net/10962/d1004375
- Description: South African and international statistics indicate that single mother families account for a large and growing proportion of the population. The economic, practical, and emotional stresses of single mothering have been documented and the experience of isolation that often accompanies their circumstances is noted in the literature. Group therapy has been utilised as a treatment plan with single mothers to provide social support and to help the women cope with stress. This thesis examines the experience of single mothers who attended a slow, open group therapy intervention for single mothers at the Child Guidance Clinic, University of Cape Town. The study is located in a feminist social constructionist tradition that recognises the multiplicity of social realities. It places the women's experiences at the foreground of the investigation so as to allow for insight into the socially constructed and first-order reality of the respondents. The research investigates the women's subjective experiences of single parenting; their experiences in the group and its impact on them; and their perceptions of group processes that may have facilitated transformation in their lives. Ten members of the single mother groups were selected for in-depth interviews. Five of the most recent graduates were interviewed and five more participants were selected as the five longest standing members currently participating in the groups. The participants' length of stay in the group at the time of interview varied between eight months and five years. The women were drawn from a range of race, class, cultural and educational backgrounds. The data was collected using individual semi-structured in -depth interviews. A constructivist grounded theory approach was employed to analyse the data. Results revealed the value of the group therapy intervention as a transformative experience for these women who face the challenges of being single parents. The participants highlighted the interpersonal factor of the group intervention as central to their experience and identified this relational aspect as the unique site of their emotional growth. The five interpersonal factors that were identified are: non-judgemental acceptance; support; commonality of experience; reciprocity; and challenge and confrontation between group members. Their accounts of personal changes brought about by participation in the group reflect internal intrapsychic transformations, which are understood in terms of increased se lf-acceptance, enhanced self-esteem, and improved self-confidence. Furthermore, their accounts of personal transformations include a reorganisation of their relational patterns from their immediate to their larger social context. The centrality of relational processes in this research reinforces contemporary theory of women's psychology, particularly theory emerging from the Stone Center, which offers a view of women's psychological growth as occurring in and through participation and engagement with others to achieve more mature and satisfying forms of relating. The accounts of personal and collective transformation provide further insight in to the concept of relational empowerment as it occurs in these groups and offer an understanding of the potentially restorative value of group therapy for single mothers. Future therapeutic interventions are considered and the need for further research in the field is discussed.
- Full Text:
- Date Issued: 2002
- Authors: Spiro, Monica
- Date: 2002
- Subjects: Single mothers -- Psychological aspects Group psychotherapy
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3100 , http://hdl.handle.net/10962/d1004375
- Description: South African and international statistics indicate that single mother families account for a large and growing proportion of the population. The economic, practical, and emotional stresses of single mothering have been documented and the experience of isolation that often accompanies their circumstances is noted in the literature. Group therapy has been utilised as a treatment plan with single mothers to provide social support and to help the women cope with stress. This thesis examines the experience of single mothers who attended a slow, open group therapy intervention for single mothers at the Child Guidance Clinic, University of Cape Town. The study is located in a feminist social constructionist tradition that recognises the multiplicity of social realities. It places the women's experiences at the foreground of the investigation so as to allow for insight into the socially constructed and first-order reality of the respondents. The research investigates the women's subjective experiences of single parenting; their experiences in the group and its impact on them; and their perceptions of group processes that may have facilitated transformation in their lives. Ten members of the single mother groups were selected for in-depth interviews. Five of the most recent graduates were interviewed and five more participants were selected as the five longest standing members currently participating in the groups. The participants' length of stay in the group at the time of interview varied between eight months and five years. The women were drawn from a range of race, class, cultural and educational backgrounds. The data was collected using individual semi-structured in -depth interviews. A constructivist grounded theory approach was employed to analyse the data. Results revealed the value of the group therapy intervention as a transformative experience for these women who face the challenges of being single parents. The participants highlighted the interpersonal factor of the group intervention as central to their experience and identified this relational aspect as the unique site of their emotional growth. The five interpersonal factors that were identified are: non-judgemental acceptance; support; commonality of experience; reciprocity; and challenge and confrontation between group members. Their accounts of personal changes brought about by participation in the group reflect internal intrapsychic transformations, which are understood in terms of increased se lf-acceptance, enhanced self-esteem, and improved self-confidence. Furthermore, their accounts of personal transformations include a reorganisation of their relational patterns from their immediate to their larger social context. The centrality of relational processes in this research reinforces contemporary theory of women's psychology, particularly theory emerging from the Stone Center, which offers a view of women's psychological growth as occurring in and through participation and engagement with others to achieve more mature and satisfying forms of relating. The accounts of personal and collective transformation provide further insight in to the concept of relational empowerment as it occurs in these groups and offer an understanding of the potentially restorative value of group therapy for single mothers. Future therapeutic interventions are considered and the need for further research in the field is discussed.
- Full Text:
- Date Issued: 2002
Product development as part of a positioning strategy for the hunting industry in the Eastern Cape
- Van Niekerk, Pieter du Preez
- Authors: Van Niekerk, Pieter du Preez
- Date: 2002
- Subjects: New products -- Marketing , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- Eastern Cape , Venison -- Marketing , Meat industry and trade -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10894 , http://hdl.handle.net/10948/111 , New products -- Marketing , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- Eastern Cape , Venison -- Marketing , Meat industry and trade -- South Africa -- Eastern Cape
- Description: In this study on product development and positioning in the hunting industry in the Eastern Cape, two conceptual frameworks were developed, based on a literature study. These positioning and product development concepts were tested against primary and secondary information gathered about the hunting industry. The game and hunting industries were in a strong growth phase at the time of this study. These industries are playing an increasingly important role in the economy of the Eastern Cape, and more and more agricultural land is utilised for game ranching. From the perspective of obtaining a competitive advantage in an increasingly competitive environment, it is therefore important for hunting providers to develop suitable products, and to position these products correctly. It is also important to investigate the characteristics of the game and hunting industries in the Eastern Cape and to get information about the characteristics of the market in which product development and positioning take place. Hunting is the most important form of game utilisation in the Eastern Cape, followed by cropping of game and live game sales. At the time of this study, the total value of the game utilised annually in the Eastern Cape was in excess of R168 million. Game utilisation seemed to be taking place on a sustainable basis, as the number of animals utilised annually was less than the annual production. Kudu and springbok provide the biggest total income, and, together with mountain reedbuck, are the most abundant species in the Eastern Cape. The main game-producing areas in the Eastern Cape coincide with the areas where extensive beef, sheep and goat farming are practised. The hunting products on offer from hunting providers, differ in certain ways. Aspects like price, type of hunting provided, game species available for hunting, terrain where hunting takes place, and various other aspects in connection with the hunt, differ from hunting provider to hunting provider. Characteristics of the hunting experience that hunters desire may be divided into core and variable elements. The core elements include: · the conditions pertaining to the hunt being spelt out clearly; · the maintenance of safety standards; · reasonable day fees; · the presence of game in sufficient numbers; and · other aspects generally desired by hunters. In the study it was found that the needs of hunters also differ regarding certain aspects of the hunting experience. These variable elements include price levels, type and availability of accommodation, and the role of the hunting provider. The core aspects that hunters desire are as a rule part of the product offering. From a product development perspective, the variable elements provide an opportunity to customise products to hunter needs. The inclusion or exclusion of variable elements from the product offering give rise to certain unique product features, and therefore provide the opportunity for product differentiation. After development, products are positioned firstly by selecting a market segment to focus on. Secondly, the needs of hunters in the target segment should be clearly identified, followed by the development of suitable products based on hunter needs, and taking into account the features of competitive offerings. Decisions should also be taken about the features to be included in the product offering to achieve product differentiation. After development of a suitable product, an image or brand should be chosen for the product, and this image should be effectively communicated to the market. A number of possible positioning options were identified for hunting providers. It was found that factors like the physical features of the ranch, available infrastructure, the market segment chosen, desires of the hunting providers, and the perception of the needs of hunters, eventually influence decisions about product development and positioning. The final decisions on positioning should take the core competencies of the hunting provider into account and should ensure that the hunting provider has the ability to fill the chosen position in the market.
- Full Text:
- Date Issued: 2002
- Authors: Van Niekerk, Pieter du Preez
- Date: 2002
- Subjects: New products -- Marketing , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- Eastern Cape , Venison -- Marketing , Meat industry and trade -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10894 , http://hdl.handle.net/10948/111 , New products -- Marketing , Hunting -- South Africa -- Eastern Cape , Game farms -- South Africa -- Eastern Cape , Venison -- Marketing , Meat industry and trade -- South Africa -- Eastern Cape
- Description: In this study on product development and positioning in the hunting industry in the Eastern Cape, two conceptual frameworks were developed, based on a literature study. These positioning and product development concepts were tested against primary and secondary information gathered about the hunting industry. The game and hunting industries were in a strong growth phase at the time of this study. These industries are playing an increasingly important role in the economy of the Eastern Cape, and more and more agricultural land is utilised for game ranching. From the perspective of obtaining a competitive advantage in an increasingly competitive environment, it is therefore important for hunting providers to develop suitable products, and to position these products correctly. It is also important to investigate the characteristics of the game and hunting industries in the Eastern Cape and to get information about the characteristics of the market in which product development and positioning take place. Hunting is the most important form of game utilisation in the Eastern Cape, followed by cropping of game and live game sales. At the time of this study, the total value of the game utilised annually in the Eastern Cape was in excess of R168 million. Game utilisation seemed to be taking place on a sustainable basis, as the number of animals utilised annually was less than the annual production. Kudu and springbok provide the biggest total income, and, together with mountain reedbuck, are the most abundant species in the Eastern Cape. The main game-producing areas in the Eastern Cape coincide with the areas where extensive beef, sheep and goat farming are practised. The hunting products on offer from hunting providers, differ in certain ways. Aspects like price, type of hunting provided, game species available for hunting, terrain where hunting takes place, and various other aspects in connection with the hunt, differ from hunting provider to hunting provider. Characteristics of the hunting experience that hunters desire may be divided into core and variable elements. The core elements include: · the conditions pertaining to the hunt being spelt out clearly; · the maintenance of safety standards; · reasonable day fees; · the presence of game in sufficient numbers; and · other aspects generally desired by hunters. In the study it was found that the needs of hunters also differ regarding certain aspects of the hunting experience. These variable elements include price levels, type and availability of accommodation, and the role of the hunting provider. The core aspects that hunters desire are as a rule part of the product offering. From a product development perspective, the variable elements provide an opportunity to customise products to hunter needs. The inclusion or exclusion of variable elements from the product offering give rise to certain unique product features, and therefore provide the opportunity for product differentiation. After development, products are positioned firstly by selecting a market segment to focus on. Secondly, the needs of hunters in the target segment should be clearly identified, followed by the development of suitable products based on hunter needs, and taking into account the features of competitive offerings. Decisions should also be taken about the features to be included in the product offering to achieve product differentiation. After development of a suitable product, an image or brand should be chosen for the product, and this image should be effectively communicated to the market. A number of possible positioning options were identified for hunting providers. It was found that factors like the physical features of the ranch, available infrastructure, the market segment chosen, desires of the hunting providers, and the perception of the needs of hunters, eventually influence decisions about product development and positioning. The final decisions on positioning should take the core competencies of the hunting provider into account and should ensure that the hunting provider has the ability to fill the chosen position in the market.
- Full Text:
- Date Issued: 2002
Promotion of liberal values in South African foreign policy : beyond the structural imperatives of the international system?
- Authors: Mkalipi, Zanethemba
- Date: 2002
- Subjects: South Africa -- Foreign relations
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2865 , http://hdl.handle.net/10962/d1007662 , South Africa -- Foreign relations
- Description: The end of the Cold War in the early 1990s led to a multilateral international system no longer divided by contending forces of capitalism and communism. In the context of South Africa, the end of the Cold War occurred at a juncture where the apartheid government was being challenged by pro-democracy forces that have fought against it for decades. The developments in the international system and in the country led to South Africa adopting universal liberal values not only in its constitution, but also in its international relations. Foreign policy documents and statements by the ministry of Foreign Affairs also reflected the country's aspiration of becoming a mediator, a facilitator for democracy and a peacemaker especially in the context of Africa. International expectation mounted as South Africa was perceived as possessing the capacity to act in a manner that advances democratic values and which gives voice to the weak nations of the world. However, the aura of a post-apartheid South Africa that would act not only in its interest, but also in the interest of the world community never fully materialised. South Africa failed to act in a manner consistent with its stated commitment to democratic values when it recognised Peoples Republic of China, an undemocratic and repressive government. It also marched into Lesotho in 1998, resulting in the destabilisation of this tiny Southern African country. These events led to an increasing criticism of the South African government. Some argued that South Africa was still inexperienced given its recent emergence as a world player. Others blamed the inconsistency on a too broad and ambitious foreign policy that set itself for failure. This study seeks to contribute to the conceptual understanding of the debate regarding the ambiguous nature of South Africa's foreign policy behaviour. It situates the conceptualisation of South Africa's foreign policy within the predominant debates in international relations between realism, political structuralism and pluralism. Firstly, it holds that the end of the Cold War and ascendancy of globalist conceptions of international relations did not lead to the inadequacy of political structuralism as an organising framework. Secondly, it attempts to clarify the gap between South Africa's foreign policy and foreign policy behaviour by employing the assumptions advanced by political structuralism, Thirdly, a case study of South Africa's foreign policy towards China, Lesotho, the Great Lakes and Swaziland is carried out. Here it is demonstrated that the ambiguities of South Africa's foreign policy are a function of the constraints imposed by the political and economic structure of the international system, It draws its conclusion by providing methodological recommendations to South Africa's foreign policy makers and future researchers in the field of foreign policy analysis.
- Full Text:
- Date Issued: 2002
- Authors: Mkalipi, Zanethemba
- Date: 2002
- Subjects: South Africa -- Foreign relations
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2865 , http://hdl.handle.net/10962/d1007662 , South Africa -- Foreign relations
- Description: The end of the Cold War in the early 1990s led to a multilateral international system no longer divided by contending forces of capitalism and communism. In the context of South Africa, the end of the Cold War occurred at a juncture where the apartheid government was being challenged by pro-democracy forces that have fought against it for decades. The developments in the international system and in the country led to South Africa adopting universal liberal values not only in its constitution, but also in its international relations. Foreign policy documents and statements by the ministry of Foreign Affairs also reflected the country's aspiration of becoming a mediator, a facilitator for democracy and a peacemaker especially in the context of Africa. International expectation mounted as South Africa was perceived as possessing the capacity to act in a manner that advances democratic values and which gives voice to the weak nations of the world. However, the aura of a post-apartheid South Africa that would act not only in its interest, but also in the interest of the world community never fully materialised. South Africa failed to act in a manner consistent with its stated commitment to democratic values when it recognised Peoples Republic of China, an undemocratic and repressive government. It also marched into Lesotho in 1998, resulting in the destabilisation of this tiny Southern African country. These events led to an increasing criticism of the South African government. Some argued that South Africa was still inexperienced given its recent emergence as a world player. Others blamed the inconsistency on a too broad and ambitious foreign policy that set itself for failure. This study seeks to contribute to the conceptual understanding of the debate regarding the ambiguous nature of South Africa's foreign policy behaviour. It situates the conceptualisation of South Africa's foreign policy within the predominant debates in international relations between realism, political structuralism and pluralism. Firstly, it holds that the end of the Cold War and ascendancy of globalist conceptions of international relations did not lead to the inadequacy of political structuralism as an organising framework. Secondly, it attempts to clarify the gap between South Africa's foreign policy and foreign policy behaviour by employing the assumptions advanced by political structuralism, Thirdly, a case study of South Africa's foreign policy towards China, Lesotho, the Great Lakes and Swaziland is carried out. Here it is demonstrated that the ambiguities of South Africa's foreign policy are a function of the constraints imposed by the political and economic structure of the international system, It draws its conclusion by providing methodological recommendations to South Africa's foreign policy makers and future researchers in the field of foreign policy analysis.
- Full Text:
- Date Issued: 2002
Psychological resilience: the role of unconscious and conscious coping strategies in the mediation of stress in high risk occupational contexts
- Authors: Alexander, Debra Geraldine
- Date: 2002
- Subjects: Hazardous occupations , Teachers -- South Africa -- Job stress , Police -- South Africa -- Job stress , Emergency medical personnel -- South Africa -- Job stress , Stress (Psychology)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3092 , http://hdl.handle.net/10962/d1003059 , Hazardous occupations , Teachers -- South Africa -- Job stress , Police -- South Africa -- Job stress , Emergency medical personnel -- South Africa -- Job stress , Stress (Psychology)
- Description: This study investigates the role of unconscious and conscious coping strategies in the mediation of stress in high risk occupational contexts. The Social Readjustment Rating Scale, the Multidimensional Coping Inventory and the Defense Style Questionnaires were completed by 194 police, ambulance and teaching personnel. A sample of 37 teachers served as a non high risk occupation control group. Descriptive statistics, regression analysis, analysis of variance, analysis of difference and principal component analysis were performed on the data. Results indicated minimal significant between group differences. Within group variances were yielded. A minor relationship between levels of stress and usage of positive and negative mechanisms was observed. The significance of these findings is discussed and recommendations made for further study.
- Full Text:
- Date Issued: 2002
- Authors: Alexander, Debra Geraldine
- Date: 2002
- Subjects: Hazardous occupations , Teachers -- South Africa -- Job stress , Police -- South Africa -- Job stress , Emergency medical personnel -- South Africa -- Job stress , Stress (Psychology)
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3092 , http://hdl.handle.net/10962/d1003059 , Hazardous occupations , Teachers -- South Africa -- Job stress , Police -- South Africa -- Job stress , Emergency medical personnel -- South Africa -- Job stress , Stress (Psychology)
- Description: This study investigates the role of unconscious and conscious coping strategies in the mediation of stress in high risk occupational contexts. The Social Readjustment Rating Scale, the Multidimensional Coping Inventory and the Defense Style Questionnaires were completed by 194 police, ambulance and teaching personnel. A sample of 37 teachers served as a non high risk occupation control group. Descriptive statistics, regression analysis, analysis of variance, analysis of difference and principal component analysis were performed on the data. Results indicated minimal significant between group differences. Within group variances were yielded. A minor relationship between levels of stress and usage of positive and negative mechanisms was observed. The significance of these findings is discussed and recommendations made for further study.
- Full Text:
- Date Issued: 2002
Quantification of corticosteroid-induced skin vasoconstriction: visual ranking, chromameter measurement or digital image analysis
- Smith, Eric W, Haigh, John M, Surber, Christian
- Authors: Smith, Eric W , Haigh, John M , Surber, Christian
- Date: 2002
- Language: English
- Type: text , Article
- Identifier: vital:6427 , http://hdl.handle.net/10962/d1006564
- Description: Topical corticosteroid formulations have been evaluated by visual grading protocols for many years. Toward a more objective methodology, several instrumental methods have been evaluated for applicability in quantifying the vasoconstriction side-effect that follows corticosteroid application to the skin. Although the chromameter has been adopted by regulatory bodies throughout the world as the current standard for topical bioequivalence determinations, there is considerable criticism of this instrument from several quarters. A preliminary comparison reported here indicates that digital image analysis provides statistically significant results that are similar to those obtained by visual assessment techniques, and shows considerably greater precision than that obtained by the chromameter. Continued evaluation of objective assessment techniques, such as digital imaging, and continued modernisation of regulatory bioequivalence requirements will assist in protecting patients and optimising clinical results.
- Full Text:
- Date Issued: 2002
- Authors: Smith, Eric W , Haigh, John M , Surber, Christian
- Date: 2002
- Language: English
- Type: text , Article
- Identifier: vital:6427 , http://hdl.handle.net/10962/d1006564
- Description: Topical corticosteroid formulations have been evaluated by visual grading protocols for many years. Toward a more objective methodology, several instrumental methods have been evaluated for applicability in quantifying the vasoconstriction side-effect that follows corticosteroid application to the skin. Although the chromameter has been adopted by regulatory bodies throughout the world as the current standard for topical bioequivalence determinations, there is considerable criticism of this instrument from several quarters. A preliminary comparison reported here indicates that digital image analysis provides statistically significant results that are similar to those obtained by visual assessment techniques, and shows considerably greater precision than that obtained by the chromameter. Continued evaluation of objective assessment techniques, such as digital imaging, and continued modernisation of regulatory bioequivalence requirements will assist in protecting patients and optimising clinical results.
- Full Text:
- Date Issued: 2002