GIS in participatory catchment management : a case study in the Kat River Valley, Eastern Cape, South Africa
- Authors: McMaster, Alistair
- Date: 2002 , 2013-05-16
- Subjects: Watershed management -- South Africa -- Eastern Cape , Geographic information systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4868 , http://hdl.handle.net/10962/d1007602 , Watershed management -- South Africa -- Eastern Cape , Geographic information systems
- Description: In water resources management in South Africa, there is an emphasis on public participation. On a river catchment basis, one of the mechanisms for such participation is the establishment of catchment forums. However, members of catchment forums, particularly those coming from poor or rural communities, cannot be expected to engage in catchment management without having been enabled to do so. This thesis considers the use of GIS in the process of enabling the Kat River Valley Catchment Forum to better participate in catchment management. The research focus is on the use of GIS to facilitate an understanding of the Kat River Catchment and associated catchment concepts, and constructive communication and sharing, among the Catchment Forum. The GIS is used in the context of "GIS for Participatory Research", an outgrowth of Public Participation GIS (PPGIS), which focuses on GIS as a tool for empowerment within participatory processes. The study has used Action Research, situated in the Critical paradigm, as a methodology. The research has included seven Forum workshop processes and one series of in-village meetings. These engagements have involved map-based appraisals, issues and resource mapping, map-based planning, and the use of on-screen GIS for presentation and sharing. The use of GIS has facilitated the creation of customised maps, the integration of village-scale mapping into a catchment scale product, the presentation of synthesised data in digital and hardcopy format and, in so doing, has allowed catchment-scale appraisal. Outcomes enabling participation in catchment management have included developed mapping skills and an enhanced understanding of the catchment as a whole, and developed conceptual access to a decision-making language (or way of thinking), among participants. Furthermore, the Forum as a whole has identified common needs, and has developed a set of map-based action plans. The research process has yielded a number of lessons regarding "GIS for participation" and the participatory framework within which it takes place. Chief among these is that the GIS operator should take on the role of a participatory practitioner.
- Full Text:
- Date Issued: 2002
- Authors: McMaster, Alistair
- Date: 2002 , 2013-05-16
- Subjects: Watershed management -- South Africa -- Eastern Cape , Geographic information systems
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4868 , http://hdl.handle.net/10962/d1007602 , Watershed management -- South Africa -- Eastern Cape , Geographic information systems
- Description: In water resources management in South Africa, there is an emphasis on public participation. On a river catchment basis, one of the mechanisms for such participation is the establishment of catchment forums. However, members of catchment forums, particularly those coming from poor or rural communities, cannot be expected to engage in catchment management without having been enabled to do so. This thesis considers the use of GIS in the process of enabling the Kat River Valley Catchment Forum to better participate in catchment management. The research focus is on the use of GIS to facilitate an understanding of the Kat River Catchment and associated catchment concepts, and constructive communication and sharing, among the Catchment Forum. The GIS is used in the context of "GIS for Participatory Research", an outgrowth of Public Participation GIS (PPGIS), which focuses on GIS as a tool for empowerment within participatory processes. The study has used Action Research, situated in the Critical paradigm, as a methodology. The research has included seven Forum workshop processes and one series of in-village meetings. These engagements have involved map-based appraisals, issues and resource mapping, map-based planning, and the use of on-screen GIS for presentation and sharing. The use of GIS has facilitated the creation of customised maps, the integration of village-scale mapping into a catchment scale product, the presentation of synthesised data in digital and hardcopy format and, in so doing, has allowed catchment-scale appraisal. Outcomes enabling participation in catchment management have included developed mapping skills and an enhanced understanding of the catchment as a whole, and developed conceptual access to a decision-making language (or way of thinking), among participants. Furthermore, the Forum as a whole has identified common needs, and has developed a set of map-based action plans. The research process has yielded a number of lessons regarding "GIS for participation" and the participatory framework within which it takes place. Chief among these is that the GIS operator should take on the role of a participatory practitioner.
- Full Text:
- Date Issued: 2002
Heterologous expression of the helicoverpa armigera stunt virus in Saccharomyces cerevisiae
- Authors: Venter, Philip Arno
- Date: 2002
- Subjects: Helicoverpa armigera Saccharomyces cerevisiae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3895 , http://hdl.handle.net/10962/d1003811
- Description: Lepidopteran insects like Helicoverpa armigera, more commonly known as the cotton bollworm, are economically important pests of a wide variety of crops throughout the world. The Helicoverpa armigera stunt virus (HaSV), a tetravirus with a bipartite single-stranded positive-sense RNA genome, has great potential as a biological pesticide against H. armigera. The larger genomic strand of this virus (RNA1) encodes the viral replicase, while the other (RNA2) encodes the 71 kDa capsid protein precursor (p71). 240 copies of p71 assemble into a procapsid with the concomitant encapsidation of the viral RNA. This is followed by a complex maturation event that is characterized by the autoproteolytic cleavage of p71 into the 64 kDa capsid protein (P64) and a 7 kDa peptide (p7). The rearrangements that occur during maturation results in the formation of mature HaSV capsids that can thereupon deliver RNA to other susceptible host cells. The principal objective of the research described in this study was to demonstrate that this virus could be assembled in Saccharomyces cerevisiae. S. cerevisiae expression vectors were constructed for the production of p71. This protein was detected in cell lysates from two different strains of S. cerevisiae, both containing either chromosomal or episomal copies of an expression cassette for P71. A number of factors relating to the expression of P71 (e.g. strains used, expression loci and expression rate) and the preparation of protein extracts from S. cerevisiae (e.g. the presence of various protease inhibitors and salt concentrations) were examined to attain optimal levels of soluble p71. A small fraction of the optimized soluble p71 was shown to be in the form of virus-like particles (VLPs), with a yield of ≤10⁷ VLPs from a 1.5l culture of P71⁺ cells. These particles were exclusively in the procapsid form, had a similar buoyant density to that of wild-type HaSV and could undergo maturation when the pH was reduced to 5. S. cerevisiae vectors were constructed for the episomal expression of the HaSV genomic RNAs. These vectors directed the transcription of RNA1 and RNA2 transcripts, which had similar sizes to those of the HaSV genomic RNAs. Mature HaSV particles were purified from cells, transgenic for P71, RNA1 and RNA2, by way of two different virus purification protocols that were developed during this study. RT-PCR analyses on RNA-extracts from these particles demonstrated that RNA transcripts, which were produced in trans with p71, could be encapsidated by HaSV capsids in S. cerevisiae. A droplet-feed bioassay on H. armigera larvae demonstrated that the S. cerevisiae-derived HaSV particles caused impaired larval development. This response was correlated with the detection of HaSV RNA2 in RNA extractions from larvae that were used in this bioassay. The results that were generated through the course of this study, provided proof for the concept of the non-host production of infectious HaSV particles from S. cerevisiae. This work could serve as a foundation for future research on the development of an expression system for the large-scale production of this virus as a biopesticide.
- Full Text:
- Date Issued: 2002
- Authors: Venter, Philip Arno
- Date: 2002
- Subjects: Helicoverpa armigera Saccharomyces cerevisiae
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3895 , http://hdl.handle.net/10962/d1003811
- Description: Lepidopteran insects like Helicoverpa armigera, more commonly known as the cotton bollworm, are economically important pests of a wide variety of crops throughout the world. The Helicoverpa armigera stunt virus (HaSV), a tetravirus with a bipartite single-stranded positive-sense RNA genome, has great potential as a biological pesticide against H. armigera. The larger genomic strand of this virus (RNA1) encodes the viral replicase, while the other (RNA2) encodes the 71 kDa capsid protein precursor (p71). 240 copies of p71 assemble into a procapsid with the concomitant encapsidation of the viral RNA. This is followed by a complex maturation event that is characterized by the autoproteolytic cleavage of p71 into the 64 kDa capsid protein (P64) and a 7 kDa peptide (p7). The rearrangements that occur during maturation results in the formation of mature HaSV capsids that can thereupon deliver RNA to other susceptible host cells. The principal objective of the research described in this study was to demonstrate that this virus could be assembled in Saccharomyces cerevisiae. S. cerevisiae expression vectors were constructed for the production of p71. This protein was detected in cell lysates from two different strains of S. cerevisiae, both containing either chromosomal or episomal copies of an expression cassette for P71. A number of factors relating to the expression of P71 (e.g. strains used, expression loci and expression rate) and the preparation of protein extracts from S. cerevisiae (e.g. the presence of various protease inhibitors and salt concentrations) were examined to attain optimal levels of soluble p71. A small fraction of the optimized soluble p71 was shown to be in the form of virus-like particles (VLPs), with a yield of ≤10⁷ VLPs from a 1.5l culture of P71⁺ cells. These particles were exclusively in the procapsid form, had a similar buoyant density to that of wild-type HaSV and could undergo maturation when the pH was reduced to 5. S. cerevisiae vectors were constructed for the episomal expression of the HaSV genomic RNAs. These vectors directed the transcription of RNA1 and RNA2 transcripts, which had similar sizes to those of the HaSV genomic RNAs. Mature HaSV particles were purified from cells, transgenic for P71, RNA1 and RNA2, by way of two different virus purification protocols that were developed during this study. RT-PCR analyses on RNA-extracts from these particles demonstrated that RNA transcripts, which were produced in trans with p71, could be encapsidated by HaSV capsids in S. cerevisiae. A droplet-feed bioassay on H. armigera larvae demonstrated that the S. cerevisiae-derived HaSV particles caused impaired larval development. This response was correlated with the detection of HaSV RNA2 in RNA extractions from larvae that were used in this bioassay. The results that were generated through the course of this study, provided proof for the concept of the non-host production of infectious HaSV particles from S. cerevisiae. This work could serve as a foundation for future research on the development of an expression system for the large-scale production of this virus as a biopesticide.
- Full Text:
- Date Issued: 2002
Identification and analysis of the factors that influence the development of female entrepreneurs in the informal sector
- Authors: Sokabo, Nobenguni B
- Date: 2002
- Subjects: Women-owned business enterprises -- South Africa , Small business -- South Africa , Businesswomen -- South Africa , Women in development -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10907 , http://hdl.handle.net/10948/98 , Women-owned business enterprises -- South Africa , Small business -- South Africa , Businesswomen -- South Africa , Women in development -- South Africa
- Description: There is a remarkable increase in the participation of females in business activities due to their involvement in the informal sector. These activities appear to be insignificant and not measurable because they are outside the regulatory framework, but they also absorb multitudes of the unemployable. Notwithstanding the challenges of low levels of education, lack of skills and finance as well as the need to balance reproductive and productive roles, females are under pressure to generate income through trading in small scale businesses that can hardly grow beyond subsistence level. With the meagre earnings from their activities, they ensure the survival of their families. If female entrepreneurs are developed and brought into the economic main stream, they will bring with them their unique survivalist techniques that will contribute towards economic development and growth in the country. This report examines the constraints that affect the development of female entrepreneurs in the informal sector.
- Full Text:
- Date Issued: 2002
- Authors: Sokabo, Nobenguni B
- Date: 2002
- Subjects: Women-owned business enterprises -- South Africa , Small business -- South Africa , Businesswomen -- South Africa , Women in development -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10907 , http://hdl.handle.net/10948/98 , Women-owned business enterprises -- South Africa , Small business -- South Africa , Businesswomen -- South Africa , Women in development -- South Africa
- Description: There is a remarkable increase in the participation of females in business activities due to their involvement in the informal sector. These activities appear to be insignificant and not measurable because they are outside the regulatory framework, but they also absorb multitudes of the unemployable. Notwithstanding the challenges of low levels of education, lack of skills and finance as well as the need to balance reproductive and productive roles, females are under pressure to generate income through trading in small scale businesses that can hardly grow beyond subsistence level. With the meagre earnings from their activities, they ensure the survival of their families. If female entrepreneurs are developed and brought into the economic main stream, they will bring with them their unique survivalist techniques that will contribute towards economic development and growth in the country. This report examines the constraints that affect the development of female entrepreneurs in the informal sector.
- Full Text:
- Date Issued: 2002
Identification of Cowdria ruminantium proteins that induce specific cellular immune responses
- Authors: Van Kleef, Mirinda
- Date: 2002
- Subjects: Ruminants--Pathogens Heartwater
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4061 , http://hdl.handle.net/10962/d1004373
- Description: Cowdria ruminantium (Cowdria) is an obligate intracellular pathogen that causes heartwater in ruminants. Cellular immunity and the type I cytokine IFN-γ have been implicated in protective immunity to heartwater. The aim of this thesis was to identify proteins of the Welgevonden isolate of Cowdria that induce lymphocyte proliferation and IFN-γ production. Differential centrifugation was found to be the simplest and most efficient method of Cowdria purification. Cowdria organisms were fractionated into their constituent proteins of between 11 and 168 kDa by continuous flow electrophoresis. The resulting fractions were tested for their ability to stimulate lymphocyte proliferation in vitro. In an attempt to simulate the natural infective process, peripheral blood mononuclear cells (PBMC) were obtained from two cattle rendered immune by infection and treatment and assayed in proliferation assays with the proteins fractions. In a parallel study, four cattle were immunised with inactivated Cowdria to determine whether their lymphocytes responded similarly. Cowdria-specific proliferation was detected for only a brief period after immunisation by infection with live organisms. This response was only detected again two to three years later. In contrast, PBMC from animals immunised with inactivated organisms were continuously responsive for at least three years. Only Cowdria proteins with molecular masses of 11, 12, 14 to 17 and 19 to 23 kDa induced proliferative responses in PBMC obtained from all six animals. Cell surface phenotypic analysis of Cowdria specific T-cell lines indicated that CD4⁺ lymphocytes were enriched over time with a concomitant increase in antigen-specific proliferation and IFN-γ production. Proteins of molecular masses 13 to 18 kDa induced CD4⁺ lymphocyte proliferation and IFN-γ production by T-cell lines from all the animals tested. Antibodies raised in a chicken and in rabbits to these low molecular weight proteins had low titres and specificity. Two-dimensional electrophoresis indicated that proteins within a single molecular weight range comprised several components with different pIs, revealing the complexity of the Cowdria proteome. This complicates the search for potentially protective antigens. Nevertheless, since they cause proliferation and IFN-γ production by lymphocytes from immunised cattle, these low molecular weight proteins merit further investigation as potential vaccine antigens. , Author: Mirinda van Kleef neé Rossouw
- Full Text:
- Date Issued: 2002
- Authors: Van Kleef, Mirinda
- Date: 2002
- Subjects: Ruminants--Pathogens Heartwater
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4061 , http://hdl.handle.net/10962/d1004373
- Description: Cowdria ruminantium (Cowdria) is an obligate intracellular pathogen that causes heartwater in ruminants. Cellular immunity and the type I cytokine IFN-γ have been implicated in protective immunity to heartwater. The aim of this thesis was to identify proteins of the Welgevonden isolate of Cowdria that induce lymphocyte proliferation and IFN-γ production. Differential centrifugation was found to be the simplest and most efficient method of Cowdria purification. Cowdria organisms were fractionated into their constituent proteins of between 11 and 168 kDa by continuous flow electrophoresis. The resulting fractions were tested for their ability to stimulate lymphocyte proliferation in vitro. In an attempt to simulate the natural infective process, peripheral blood mononuclear cells (PBMC) were obtained from two cattle rendered immune by infection and treatment and assayed in proliferation assays with the proteins fractions. In a parallel study, four cattle were immunised with inactivated Cowdria to determine whether their lymphocytes responded similarly. Cowdria-specific proliferation was detected for only a brief period after immunisation by infection with live organisms. This response was only detected again two to three years later. In contrast, PBMC from animals immunised with inactivated organisms were continuously responsive for at least three years. Only Cowdria proteins with molecular masses of 11, 12, 14 to 17 and 19 to 23 kDa induced proliferative responses in PBMC obtained from all six animals. Cell surface phenotypic analysis of Cowdria specific T-cell lines indicated that CD4⁺ lymphocytes were enriched over time with a concomitant increase in antigen-specific proliferation and IFN-γ production. Proteins of molecular masses 13 to 18 kDa induced CD4⁺ lymphocyte proliferation and IFN-γ production by T-cell lines from all the animals tested. Antibodies raised in a chicken and in rabbits to these low molecular weight proteins had low titres and specificity. Two-dimensional electrophoresis indicated that proteins within a single molecular weight range comprised several components with different pIs, revealing the complexity of the Cowdria proteome. This complicates the search for potentially protective antigens. Nevertheless, since they cause proliferation and IFN-γ production by lymphocytes from immunised cattle, these low molecular weight proteins merit further investigation as potential vaccine antigens. , Author: Mirinda van Kleef neé Rossouw
- Full Text:
- Date Issued: 2002
Identifying the need for the development of an instrument to determine senior phase teachers' science-assessment competence
- Authors: Lombard, Elsa Helena
- Date: 2002
- Subjects: Science -- Ability testing -- South Africa , Science -- Study and teaching -- South Africa -- Port Elizabeth -- Evaluation , Educational tests and measurements -- South Africa , Competency-based education -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10786 , http://hdl.handle.net/10948/100 , Science -- Ability testing -- South Africa , Science -- Study and teaching -- South Africa -- Port Elizabeth -- Evaluation , Educational tests and measurements -- South Africa , Competency-based education -- South Africa
- Description: The focus of this study is the competences expected of teachers in the senior phase to assess the Natural Sciences learning area. In order to be in line with the new developments, the South African science teacher will need relevant assessment training in order to utilise appropriate techniques that are in line with the new educational philosophy. The question arises: What competences do teachers need for assessing science in the senior phase? An ethnographic case study was implemented as research methodology in the descriptive research paradigm. The investigation comprised observing the classroom practices of a sample of three senior phase science teachers in two primary schools and in one secondary school in the Port Elizabeth region. The data obtained from the observations were triangulated with related artefacts produced by both the teachers and the learners in each case. In order to establish these expected competences a document analysis was done from a selection of South African documents. The descriptions of the real life assessment practices of the sample of science teachers were then compared with the competences expected by the South African education system. The comparison between the real-life assessment practices and the expected practices concurred with Shepard’s (2000, p.12) belief that the abilities needed to implement classroom assessment “are daunting”. The classroom-based assessment practices of the sample of teachers revealed a variety of assessment beliefs, practices and competence. The needs of these teachers are so diversified and intense that individualised professional development is needed if sustained implementation of the new curriculum and accompanying assessment competences is to be facilitated. The research established the need to develop an instrument that the science teachers can use to assess their own competence. There should be training modules drawn up in line with this instrument. Teachers should be able to choose the professional development modules that would address their own unique needs
- Full Text:
- Date Issued: 2002
- Authors: Lombard, Elsa Helena
- Date: 2002
- Subjects: Science -- Ability testing -- South Africa , Science -- Study and teaching -- South Africa -- Port Elizabeth -- Evaluation , Educational tests and measurements -- South Africa , Competency-based education -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10786 , http://hdl.handle.net/10948/100 , Science -- Ability testing -- South Africa , Science -- Study and teaching -- South Africa -- Port Elizabeth -- Evaluation , Educational tests and measurements -- South Africa , Competency-based education -- South Africa
- Description: The focus of this study is the competences expected of teachers in the senior phase to assess the Natural Sciences learning area. In order to be in line with the new developments, the South African science teacher will need relevant assessment training in order to utilise appropriate techniques that are in line with the new educational philosophy. The question arises: What competences do teachers need for assessing science in the senior phase? An ethnographic case study was implemented as research methodology in the descriptive research paradigm. The investigation comprised observing the classroom practices of a sample of three senior phase science teachers in two primary schools and in one secondary school in the Port Elizabeth region. The data obtained from the observations were triangulated with related artefacts produced by both the teachers and the learners in each case. In order to establish these expected competences a document analysis was done from a selection of South African documents. The descriptions of the real life assessment practices of the sample of science teachers were then compared with the competences expected by the South African education system. The comparison between the real-life assessment practices and the expected practices concurred with Shepard’s (2000, p.12) belief that the abilities needed to implement classroom assessment “are daunting”. The classroom-based assessment practices of the sample of teachers revealed a variety of assessment beliefs, practices and competence. The needs of these teachers are so diversified and intense that individualised professional development is needed if sustained implementation of the new curriculum and accompanying assessment competences is to be facilitated. The research established the need to develop an instrument that the science teachers can use to assess their own competence. There should be training modules drawn up in line with this instrument. Teachers should be able to choose the professional development modules that would address their own unique needs
- Full Text:
- Date Issued: 2002
Imaging the metaphysical in contemporary art practice : a comparative study of intertextuality, poststructuralism and metaphysical symbolism
- Authors: Opperman, J. A.
- Date: 2002
- Subjects: Mind and body , Metaphysics in art
- Language: English
- Type: Thesis , Masters , MTech (Fine Art, Painting)
- Identifier: vital:10762 , http://hdl.handle.net/10948/101 , Mind and body , Metaphysics in art
- Description: It was then that I decided to investigate how contemporary forms of metaphysical imaging have evolved formally and stylistically. I began to question how such approaches might be informed by current philosophical thought, given that many contemporary theorists have adopted a sceptical view towards metaphysical discourse. This point of contention presented me with the initial challenge of finding an artist whose exploration of metaphysical content is supported by topical philosophical thought. I intended this inquiry to serve as a basis from which to develop my own approach to imaging metaphysical content and to situate it within the context of contemporary thought.
- Full Text:
- Date Issued: 2002
- Authors: Opperman, J. A.
- Date: 2002
- Subjects: Mind and body , Metaphysics in art
- Language: English
- Type: Thesis , Masters , MTech (Fine Art, Painting)
- Identifier: vital:10762 , http://hdl.handle.net/10948/101 , Mind and body , Metaphysics in art
- Description: It was then that I decided to investigate how contemporary forms of metaphysical imaging have evolved formally and stylistically. I began to question how such approaches might be informed by current philosophical thought, given that many contemporary theorists have adopted a sceptical view towards metaphysical discourse. This point of contention presented me with the initial challenge of finding an artist whose exploration of metaphysical content is supported by topical philosophical thought. I intended this inquiry to serve as a basis from which to develop my own approach to imaging metaphysical content and to situate it within the context of contemporary thought.
- Full Text:
- Date Issued: 2002
Implementing non-photorealistic rendering enhancements with real-time performance
- Authors: Winnemöller, Holger
- Date: 2002 , 2013-05-09
- Subjects: Computer animation , Computer graphics , Real-time data processing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4580 , http://hdl.handle.net/10962/d1003135 , Computer animation , Computer graphics , Real-time data processing
- Description: We describe quality and performance enhancements, which work in real-time, to all well-known Non-photorealistic (NPR) rendering styles for use in an interactive context. These include Comic rendering, Sketch rendering, Hatching and Painterly rendering, but we also attempt and justify a widening of the established definition of what is considered NPR. In the individual Chapters, we identify typical stylistic elements of the different NPR styles. We list problems that need to be solved in order to implement the various renderers. Standard solutions available in the literature are introduced and in all cases extended and optimised. In particular, we extend the lighting model of the comic renderer to include a specular component and introduce multiple inter-related but independent geometric approximations which greatly improve rendering performance. We implement two completely different solutions to random perturbation sketching, solve temporal coherence issues for coal sketching and find an unexpected use for 3D textures to implement hatch-shading. Textured brushes of painterly rendering are extended by properties such as stroke-direction and texture, motion, paint capacity, opacity and emission, making them more flexible and versatile. Brushes are also provided with a minimal amount of intelligence, so that they can help in maximising screen coverage of brushes. We furthermore devise a completely new NPR style, which we call super-realistic and show how sample images can be tweened in real-time to produce an image-based six degree-of-freedom renderer performing at roughly 450 frames per second. Performance values for our other renderers all lie between 10 and over 400 frames per second on homePC hardware, justifying our real-time claim. A large number of sample screen-shots, illustrations and animations demonstrate the visual fidelity of our rendered images. In essence, we successfully achieve our attempted goals of increasing the creative, expressive and communicative potential of individual NPR styles, increasing performance of most of them, adding original and interesting visual qualities, and exploring new techniques or existing ones in novel ways. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2002
- Authors: Winnemöller, Holger
- Date: 2002 , 2013-05-09
- Subjects: Computer animation , Computer graphics , Real-time data processing
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4580 , http://hdl.handle.net/10962/d1003135 , Computer animation , Computer graphics , Real-time data processing
- Description: We describe quality and performance enhancements, which work in real-time, to all well-known Non-photorealistic (NPR) rendering styles for use in an interactive context. These include Comic rendering, Sketch rendering, Hatching and Painterly rendering, but we also attempt and justify a widening of the established definition of what is considered NPR. In the individual Chapters, we identify typical stylistic elements of the different NPR styles. We list problems that need to be solved in order to implement the various renderers. Standard solutions available in the literature are introduced and in all cases extended and optimised. In particular, we extend the lighting model of the comic renderer to include a specular component and introduce multiple inter-related but independent geometric approximations which greatly improve rendering performance. We implement two completely different solutions to random perturbation sketching, solve temporal coherence issues for coal sketching and find an unexpected use for 3D textures to implement hatch-shading. Textured brushes of painterly rendering are extended by properties such as stroke-direction and texture, motion, paint capacity, opacity and emission, making them more flexible and versatile. Brushes are also provided with a minimal amount of intelligence, so that they can help in maximising screen coverage of brushes. We furthermore devise a completely new NPR style, which we call super-realistic and show how sample images can be tweened in real-time to produce an image-based six degree-of-freedom renderer performing at roughly 450 frames per second. Performance values for our other renderers all lie between 10 and over 400 frames per second on homePC hardware, justifying our real-time claim. A large number of sample screen-shots, illustrations and animations demonstrate the visual fidelity of our rendered images. In essence, we successfully achieve our attempted goals of increasing the creative, expressive and communicative potential of individual NPR styles, increasing performance of most of them, adding original and interesting visual qualities, and exploring new techniques or existing ones in novel ways. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
- Full Text:
- Date Issued: 2002
Improving job performance by using non-monetary reward systems to motivate low-skilled workers in the automotive component industry
- Authors: Taljaard, Jacob Johannes
- Date: 2002
- Subjects: Employee motivation -- South Africa , Performance awards
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10910 , http://hdl.handle.net/10948/131 , Employee motivation -- South Africa , Performance awards
- Description: Automotive component manufacturing companies where the labour is low skilled and the processes are labour intensive, are being challenged on a more regular basis to find methods to satisfy needs to motivate employees to improve performance. Automotive companies are becoming more under pressure to motivate employees through non-monetary rewards, due to collective bargaining which has made pay for performance very inflexible. It is because of this fact that employers have to assess non-monetary reward methods to motivate employees to improve performance. To be motivators, rewards must be aligned with the needs of people and the things that they value. If these rewards are aligned with employees needs, this could lead to increase in employee motivation, which will in turn lead to improvement in performance, and therefore lead to companies becoming more competitive. This research paper aims to assess what would be the motivators when establishing a non-monetary reward system. To this end the various motivational theories are presented which clearly identifies what needs people have and how they can be satisfied to change behaviour and therefore improve performance. Secondly, reward systems are discussed with various types of rewards being considered and more specifically non-monetary rewards. Applied research was undertaken to determine non-monetary rewards that will motivate low-skilled employees to improve performance. A survey, with the aid of a structured questionnaire, was used to gain information from 60 employees. The research was conducted in three companies that manufacture components for the auto industry. The majority of the respondents indicated that: 1. basic needs must be satisfied with monetary rewards; 2. non-monetary rewards, if linked to higher hierarchical needs, will then motivate employees; 3. non-monetary rewards should preferably be of a physical nature such as certificates, caps and t-shirts; 4. satisfaction of these higher level needs motivate employees and improve their performance; 5. employees prefer feedback and recognition as a non-monetary reward on a regular basis, and 6. the needs of employees should be identified through a survey to establish which rewards will satisfy these needs.
- Full Text:
- Date Issued: 2002
- Authors: Taljaard, Jacob Johannes
- Date: 2002
- Subjects: Employee motivation -- South Africa , Performance awards
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10910 , http://hdl.handle.net/10948/131 , Employee motivation -- South Africa , Performance awards
- Description: Automotive component manufacturing companies where the labour is low skilled and the processes are labour intensive, are being challenged on a more regular basis to find methods to satisfy needs to motivate employees to improve performance. Automotive companies are becoming more under pressure to motivate employees through non-monetary rewards, due to collective bargaining which has made pay for performance very inflexible. It is because of this fact that employers have to assess non-monetary reward methods to motivate employees to improve performance. To be motivators, rewards must be aligned with the needs of people and the things that they value. If these rewards are aligned with employees needs, this could lead to increase in employee motivation, which will in turn lead to improvement in performance, and therefore lead to companies becoming more competitive. This research paper aims to assess what would be the motivators when establishing a non-monetary reward system. To this end the various motivational theories are presented which clearly identifies what needs people have and how they can be satisfied to change behaviour and therefore improve performance. Secondly, reward systems are discussed with various types of rewards being considered and more specifically non-monetary rewards. Applied research was undertaken to determine non-monetary rewards that will motivate low-skilled employees to improve performance. A survey, with the aid of a structured questionnaire, was used to gain information from 60 employees. The research was conducted in three companies that manufacture components for the auto industry. The majority of the respondents indicated that: 1. basic needs must be satisfied with monetary rewards; 2. non-monetary rewards, if linked to higher hierarchical needs, will then motivate employees; 3. non-monetary rewards should preferably be of a physical nature such as certificates, caps and t-shirts; 4. satisfaction of these higher level needs motivate employees and improve their performance; 5. employees prefer feedback and recognition as a non-monetary reward on a regular basis, and 6. the needs of employees should be identified through a survey to establish which rewards will satisfy these needs.
- Full Text:
- Date Issued: 2002
In the best interests of the child? : a case study of the psychological discourses of the custody decision-making process in a South African context
- Authors: Durrbaum, René
- Date: 2002
- Subjects: Custody of children -- South Africa -- Psychological aspects Children of divorced parents -- South Africa -- Psychology
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3153 , http://hdl.handle.net/10962/d1007484
- Description: This study focuses on the process of custody decision-making in a South African divorce context with the aim of critically examining the operation of the principle of the best interests of the child. A narrative approach is incorporated into Parker and Fairclough's discourse analytic approaches in the context of an instrumental case study. More specifically, the focus falls on moving beyond the understandings of custody embodied within the current psychological literature in order to examine the relationship between theory and practice and to view custody as a dynamic process at both a textual and analytical level. Concepts of dialoguing, context, audience and intertextuality together with a storied approach are central. Further, an attempt is made to provide a disruptive reading of the case through the use of notions of power, ideology and institutional practices embedded within the case and its broader contexts. The analysis demonstrates the need for decision-making to be viewed as a broader process situated across multiple professional, institutional and socio-political texts and contexts. Further, it is argued that in order for the process to uphold the principle of the child's best interests, specialised training must be supplemented with changes at the level of policy, aimed at moving toward a more inclusive, process-oriented approach to custody decision-making.
- Full Text:
- Date Issued: 2002
- Authors: Durrbaum, René
- Date: 2002
- Subjects: Custody of children -- South Africa -- Psychological aspects Children of divorced parents -- South Africa -- Psychology
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:3153 , http://hdl.handle.net/10962/d1007484
- Description: This study focuses on the process of custody decision-making in a South African divorce context with the aim of critically examining the operation of the principle of the best interests of the child. A narrative approach is incorporated into Parker and Fairclough's discourse analytic approaches in the context of an instrumental case study. More specifically, the focus falls on moving beyond the understandings of custody embodied within the current psychological literature in order to examine the relationship between theory and practice and to view custody as a dynamic process at both a textual and analytical level. Concepts of dialoguing, context, audience and intertextuality together with a storied approach are central. Further, an attempt is made to provide a disruptive reading of the case through the use of notions of power, ideology and institutional practices embedded within the case and its broader contexts. The analysis demonstrates the need for decision-making to be viewed as a broader process situated across multiple professional, institutional and socio-political texts and contexts. Further, it is argued that in order for the process to uphold the principle of the child's best interests, specialised training must be supplemented with changes at the level of policy, aimed at moving toward a more inclusive, process-oriented approach to custody decision-making.
- Full Text:
- Date Issued: 2002
Intelligent gripper design and application for automated part recognition and gripping
- Authors: Wang, Jianqiang
- Date: 2002
- Subjects: Automatic control , Robots, Industrial , Robotics
- Language: English
- Type: Thesis , Doctoral , DTech (Engineering)
- Identifier: vital:10816 , http://hdl.handle.net/10948/102 , Automatic control , Robots, Industrial , Robotics
- Description: Intelligent gripping may be achieved through gripper design, automated part recognition, intelligent algorithm for control of the gripper, and on-line decision-making based on sensory data. A generic framework which integrates sensory data, part recognition, decision-making and gripper control to achieve intelligent gripping based on ABB industrial robot is constructed. The three-fingered gripper actuated by a linear servo actuator designed and developed in this project for precise speed and position control is capable of handling a large variety of objects. Generic algorithms for intelligent part recognition are developed. Edge vector representation is discussed. Object geometric features are extracted. Fuzzy logic is successfully utilized to enhance the intelligence of the system. The generic fuzzy logic algorithm, which may also find application in other fields, is presented. Model-based gripping planning algorithm which is capable of extracting object grasp features from its geometric features and reasoning out grasp model for objects with different geometry is proposed. Manipulator trajectory planning solves the problem of generating robot programs automatically. Object-oriented programming technique based on Visual C++ MFC is used to constitute the system software so as to ensure the compatibility, expandability and modular programming design. Hierarchical architecture for intelligent gripping is discussed, which partitions the robot’s functionalities into high-level (modeling, recognizing, planning and perception) layers, and low-level (sensing, interfacing and execute) layers. Individual system modules are integrated seamlessly to constitute the intelligent gripping system.
- Full Text:
- Date Issued: 2002
- Authors: Wang, Jianqiang
- Date: 2002
- Subjects: Automatic control , Robots, Industrial , Robotics
- Language: English
- Type: Thesis , Doctoral , DTech (Engineering)
- Identifier: vital:10816 , http://hdl.handle.net/10948/102 , Automatic control , Robots, Industrial , Robotics
- Description: Intelligent gripping may be achieved through gripper design, automated part recognition, intelligent algorithm for control of the gripper, and on-line decision-making based on sensory data. A generic framework which integrates sensory data, part recognition, decision-making and gripper control to achieve intelligent gripping based on ABB industrial robot is constructed. The three-fingered gripper actuated by a linear servo actuator designed and developed in this project for precise speed and position control is capable of handling a large variety of objects. Generic algorithms for intelligent part recognition are developed. Edge vector representation is discussed. Object geometric features are extracted. Fuzzy logic is successfully utilized to enhance the intelligence of the system. The generic fuzzy logic algorithm, which may also find application in other fields, is presented. Model-based gripping planning algorithm which is capable of extracting object grasp features from its geometric features and reasoning out grasp model for objects with different geometry is proposed. Manipulator trajectory planning solves the problem of generating robot programs automatically. Object-oriented programming technique based on Visual C++ MFC is used to constitute the system software so as to ensure the compatibility, expandability and modular programming design. Hierarchical architecture for intelligent gripping is discussed, which partitions the robot’s functionalities into high-level (modeling, recognizing, planning and perception) layers, and low-level (sensing, interfacing and execute) layers. Individual system modules are integrated seamlessly to constitute the intelligent gripping system.
- Full Text:
- Date Issued: 2002
Investigation of the bioconversion of constituents of olive effluents for the production of valuable chemical compounds
- Authors: Notshe, Thandiwe Loretta
- Date: 2002
- Subjects: Phenols , Sewage -- Purification , Effluent quality
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4078 , http://hdl.handle.net/10962/d1007446 , Phenols , Sewage -- Purification , Effluent quality
- Description: Olive mill wastewater is produced in large quantities during the production of olive oil and olive production effluents are produced during the processing of olives. This project was planned to find a use for constituents found in olive production wastewater. The task was carried out by first characterizing the olive effluents, then screening microorganisms for growth in the effluents and reduction of the pollutant properties of the effluents. An investigation into the biotransformation of aromatic compounds present in the effluents into useful chemicals, was carried out. The olive production effluents were collected from different stages in the process for treating olive wastewater, viz, a fermentation tank (FB), the surface of a digester (LV) and an evaporation pond (SO). The three effluents were characterized by investigating their phenolic composition. Protocatechuic acid, vanillic acid, syringic acid, hydroxyphenyl acetic acid, coumaric acid and ferulic acid were identified in an olive effluent, FB, using thin layer chromatography (TLC) and High perfomance liquid chromatography (HPLC). Hydroxyphenyl acetic acid constitutes almost 60% of the organics in olive effluent FB. Five bacteria, namely RU-LV1; RU-FBI and RU-FB2; RU-SOI and RU-S02, were isolated from the olive effluents LV, FB and SO respectively. These isolates were found to be halotolerant and were able to grow over a broad temperature and pH range, with the maximum temperature and pH for growth being 28°C and pH 7 respectively. A range of microorganisms were evaluated for their ability to grow and reduce the total phenolic content of the olive effluents. Among these Neurospora crassa showed the highest potential for the biological reduction of total phenolics in olive effluents. Approximately 70% of the total phenolic content was removed by N. crassa. Trametes verscilor, Pseudomonas putida strains, RU-KMI and RU-KM3s, and the bacteria isolated from olive effluents could also degrade the total phenolic content of olive effluents, but to a lesser extent. The ability of the five bacterial isolates to grow and degrade aromatic compounds was assessed by growing them in medium with standard aromatic compounds. RU-L V1 degraded 96%, 100%, 73% and 100% of caffeic acid, protocatechuic acid, p-coumaric acid and vanillic acid respectively. The other isolates degraded caffeic acid and protocatechuic acid, but their ability to degraded p-coumaric acid and vanillic acid was found to be lesser than the ability of RU-LV1 to degrade the same aromatic compounds. Whole cells of RU-LV1 degraded vanillic acid but no metabolic products were observed on HPLC analysis. Resting cells, French pressed extract, cell free extracts and cell debris from RU-LV1 cells induced with vanillic acid degraded vanillic acid, ferulic acid and vanillin at rates higher than those obtained from non-induced cultures. No products were observed during the degradation of vanillic acid. Ferulic acid was converted into vanillic acid by French pressed extract, cell free extract and cell debris of RU-LV1. The maximum yield of vanillic acid as a product (0 .23 mM, 50 %yield) was obtained when cell free extracts of RU-LVI, grown in glucose and induced by vanillic acid, were used for the degradation of 0.4 mM ferulic acid. Vanillin was rapidly converted into vanillic acid by resting cells, cell free extracts and French pressed extract of RU-LVI. Using molecular techniques, the similarity ranking of the RU-LVI 16S rRNA gene and its clone showed a high similarity to Corynebacterium glutamicum and Corynebacterium acedopltilum. The rapid degradation of vanillin to vanillic acid suggests that extracts from RU-LV1 degrade ferulic acid into vanillin which is immediately oxidized to vanillic acid. Vanillic acid is also considered as a high value chemical. This project has a potential of producing useful chemicals from cheap substrates that can be found in olive effluents. , KMBT_363
- Full Text:
- Date Issued: 2002
- Authors: Notshe, Thandiwe Loretta
- Date: 2002
- Subjects: Phenols , Sewage -- Purification , Effluent quality
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4078 , http://hdl.handle.net/10962/d1007446 , Phenols , Sewage -- Purification , Effluent quality
- Description: Olive mill wastewater is produced in large quantities during the production of olive oil and olive production effluents are produced during the processing of olives. This project was planned to find a use for constituents found in olive production wastewater. The task was carried out by first characterizing the olive effluents, then screening microorganisms for growth in the effluents and reduction of the pollutant properties of the effluents. An investigation into the biotransformation of aromatic compounds present in the effluents into useful chemicals, was carried out. The olive production effluents were collected from different stages in the process for treating olive wastewater, viz, a fermentation tank (FB), the surface of a digester (LV) and an evaporation pond (SO). The three effluents were characterized by investigating their phenolic composition. Protocatechuic acid, vanillic acid, syringic acid, hydroxyphenyl acetic acid, coumaric acid and ferulic acid were identified in an olive effluent, FB, using thin layer chromatography (TLC) and High perfomance liquid chromatography (HPLC). Hydroxyphenyl acetic acid constitutes almost 60% of the organics in olive effluent FB. Five bacteria, namely RU-LV1; RU-FBI and RU-FB2; RU-SOI and RU-S02, were isolated from the olive effluents LV, FB and SO respectively. These isolates were found to be halotolerant and were able to grow over a broad temperature and pH range, with the maximum temperature and pH for growth being 28°C and pH 7 respectively. A range of microorganisms were evaluated for their ability to grow and reduce the total phenolic content of the olive effluents. Among these Neurospora crassa showed the highest potential for the biological reduction of total phenolics in olive effluents. Approximately 70% of the total phenolic content was removed by N. crassa. Trametes verscilor, Pseudomonas putida strains, RU-KMI and RU-KM3s, and the bacteria isolated from olive effluents could also degrade the total phenolic content of olive effluents, but to a lesser extent. The ability of the five bacterial isolates to grow and degrade aromatic compounds was assessed by growing them in medium with standard aromatic compounds. RU-L V1 degraded 96%, 100%, 73% and 100% of caffeic acid, protocatechuic acid, p-coumaric acid and vanillic acid respectively. The other isolates degraded caffeic acid and protocatechuic acid, but their ability to degraded p-coumaric acid and vanillic acid was found to be lesser than the ability of RU-LV1 to degrade the same aromatic compounds. Whole cells of RU-LV1 degraded vanillic acid but no metabolic products were observed on HPLC analysis. Resting cells, French pressed extract, cell free extracts and cell debris from RU-LV1 cells induced with vanillic acid degraded vanillic acid, ferulic acid and vanillin at rates higher than those obtained from non-induced cultures. No products were observed during the degradation of vanillic acid. Ferulic acid was converted into vanillic acid by French pressed extract, cell free extract and cell debris of RU-LV1. The maximum yield of vanillic acid as a product (0 .23 mM, 50 %yield) was obtained when cell free extracts of RU-LVI, grown in glucose and induced by vanillic acid, were used for the degradation of 0.4 mM ferulic acid. Vanillin was rapidly converted into vanillic acid by resting cells, cell free extracts and French pressed extract of RU-LVI. Using molecular techniques, the similarity ranking of the RU-LVI 16S rRNA gene and its clone showed a high similarity to Corynebacterium glutamicum and Corynebacterium acedopltilum. The rapid degradation of vanillin to vanillic acid suggests that extracts from RU-LV1 degrade ferulic acid into vanillin which is immediately oxidized to vanillic acid. Vanillic acid is also considered as a high value chemical. This project has a potential of producing useful chemicals from cheap substrates that can be found in olive effluents. , KMBT_363
- Full Text:
- Date Issued: 2002
Leaders' and participants' perceptions of the management of the Life Science Project in Namibia
- Authors: Kirkegaard, Niels Hugo
- Date: 2002
- Subjects: Life Science Project (Namibia) Educational leadership Educational leadership -- Namibia School management and organization School management and organization -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1662 , http://hdl.handle.net/10962/d1003545
- Description: After Independence in 1991, Namibia embarked on implementing a new and different educational system. This system was seen as a radical departure from the old apartheid system. The Namibian government approached Ibis, a Danish NGO, to support the change process by establishing and developing a new subject, life science, in Junior Secondary schools in Namibia through the Life Science Project (LSP). In a project of this nature, where a foreign (Danish) educational intervention in a relatively young and new democracy is the issue, cross-cultural aspects are likely to emerge, and these are the focus of this study. This half-thesis is an attempt to illuminate, not to evaluate, managerial as well as cross-cultural features of the project based on perceptions of selected Danish managers and Namibian advisory teachers from the former LSP expressed in the goal of the research: - To explore selected leaders’ and participants’ perception of the management of the Life Science Project. In line with this goal, I elected to conduct the research in the interpretive paradigm, using unstructured interviews as my chief source of data. The findings illuminate what would appear to be an inconsistency in the management of the project. The project seemed to be able to accommodate regional and even personal differences and to be flexible to internal changes. At the same time it appears that in its relationship to the external or task environment it did not show the same openness and flexibility to accommodate diversity. It is suggested that this could be a result of the apparent failure on the part of the project to clarify its own underlying values. The study also reveals interesting and unexpected perceptions of leadership, which may also be interpreted in terms of cultural values and beliefs. These two features of managerial issues could lead one to reflect upon the importance of recognising values in organisations which work across cultures.
- Full Text:
- Date Issued: 2002
- Authors: Kirkegaard, Niels Hugo
- Date: 2002
- Subjects: Life Science Project (Namibia) Educational leadership Educational leadership -- Namibia School management and organization School management and organization -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1662 , http://hdl.handle.net/10962/d1003545
- Description: After Independence in 1991, Namibia embarked on implementing a new and different educational system. This system was seen as a radical departure from the old apartheid system. The Namibian government approached Ibis, a Danish NGO, to support the change process by establishing and developing a new subject, life science, in Junior Secondary schools in Namibia through the Life Science Project (LSP). In a project of this nature, where a foreign (Danish) educational intervention in a relatively young and new democracy is the issue, cross-cultural aspects are likely to emerge, and these are the focus of this study. This half-thesis is an attempt to illuminate, not to evaluate, managerial as well as cross-cultural features of the project based on perceptions of selected Danish managers and Namibian advisory teachers from the former LSP expressed in the goal of the research: - To explore selected leaders’ and participants’ perception of the management of the Life Science Project. In line with this goal, I elected to conduct the research in the interpretive paradigm, using unstructured interviews as my chief source of data. The findings illuminate what would appear to be an inconsistency in the management of the project. The project seemed to be able to accommodate regional and even personal differences and to be flexible to internal changes. At the same time it appears that in its relationship to the external or task environment it did not show the same openness and flexibility to accommodate diversity. It is suggested that this could be a result of the apparent failure on the part of the project to clarify its own underlying values. The study also reveals interesting and unexpected perceptions of leadership, which may also be interpreted in terms of cultural values and beliefs. These two features of managerial issues could lead one to reflect upon the importance of recognising values in organisations which work across cultures.
- Full Text:
- Date Issued: 2002
Modelling the broiler performance under small-scales and semi commercial management condition
- Authors: Prince, Siliga Hulisani
- Date: 2002
- Subjects: Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MTech (Agricultural Management)
- Identifier: vital:10963 , http://hdl.handle.net/10948/110 , Broilers (Chickens)
- Description: Introduction : World poultry meat consumption consists of three major segments: broilers, turkeys, and other poultry which includes spent egg layers, spent breeder hens/males, ducks, geese, guinea-fowl, pheasants, quail, ratites, ostriches and emus. Broilers clearly dominate the world poultry consumption contributing about 70 percent to the world poultry market. Turkeys account for about eight percent while other poultry provides the balance of 22 percent (Roenick, 1998). The world broiler industry has been, and continues to be a very dynamic industry. It has been typified with unprecedented growth in terms of production. In 1961, the world produced 6.5 billion broilers. By 1990, the total annual production was a little over 27 billion broilers and by 1996, total world production had grown to 35.3 billion (Van der Sluis., 1999). This represents a fivefold increase in 35 years, and it has not stopped growing since, with world production surpassed 38 billion in 1998 (Van der Sluis., 1999). In Africa the human population was estimated to be 819.9 million, while the total poultry population of the continent was estimated as 1.133 million chickens, 15 million ducks and seven million turkeys in 1998. Production scale being 1.781701 metric tones (MT) of hen eggs, 2.269000 MT of chickens’ meat, 32.824MT of turkey meat and 52.989MT of duck meat (Gueye, 2000). Commercial poultry products are also imported and exported. For example, 12.000 metric tons of poultry meat was estimated to have been exported from South Africa in 1999, whereas 87.000 and 10.000 metric tons of poultry meat was imported into South Africa and Egypt, respectively (Gueye, 2000). In South Africa poultry production is moving toward the 21st century with the potential for increased development being greater than any other sector of the agricultural industry. The small-scale to medium-scale or semi-commercial farmer is becoming a role-player that needs to be serviced by the poultry industry (Fourie, 2000). The industry will have to take up the challenges that are facing an entrepreneur starting with a poultry venture. The poultry industry has developed from a humble beginning at the turn of the century into a multi-million Rand enterprise where protein is provided through the commercial and small marketing sector (Fourie, 2000). Some of the larger commercial companies market three million birds per week. It is estimated that the commercial company sector is responsible for 75 to 85 percent of production and marketing of white meat in this country whereas the small-scale and medium-scale or semi commercial poultry production enterprises provide 20 to 25 percent of the white meat through the sales of slaughtered and live poultry sale to rural, peri-urban and urban settlements (Fourie., 2000). Small-scale and semi-commercial broiler production is developed by entrepreneurs who buy day-old chicks from the big commercial hatcheries, rear them to the age of five to eight weeks and sell them through a marketing network or small outlets. The small-scale consist of farmers who reared 100 t0 1000 chickens per batch and semi-commercial consist of farmers who reared 1000 to 5000 chickens per batch. These types of farmers acquire very little technical backup in terms of a training and services center where assistance is available every day of the week. The broiler industry requires birds that are of commercial crosses selected for their ability to grow very fast and produce a good quality carcass in the shortest time frame. The small farmers purchase broiler stock, as the day-old chicks from commercial hatcheries and reared them up to six to eight weeks before slaughtered or sold as live chickens. The selling of live chickens through a network outlets system is becoming an industry that is growing at a steady pace, as household food security is becoming important to communities (Fourie, 2000). The price of feed is the single most expensive item on the list of expenses of a farmer because of their financial constraints. The small-scale and semicommercial broiler farmer is faced with the problem of buying small quantities of feed at an inflated price. The problem can be alleviated by groups of small farmers joining co-operative and buying feeds in bulk from suppliers and redistributing to small farmers. The community co-operative can once again play a major role in the distribution of small amounts of feed to its member. The biggest challenge is to provide training with a “hands on” approach. It will be ideal to have a training center where small farmers can be trained in all aspects of poultry production. The training facility will have to operate as a fully operational poultry unit with no risks to bio-security of a commercial enterprise. Training will have to be provided in aspects like hatchery, housing, broilers and record management depending on the farmer’s needs. There is also a need for the research on broiler performance under small-scale and semi commercial farming. Research in this sector of poultry production should look in appropriate feeds, feeding, technology, genotype and performance of genotypes under the system. Emphasis in this study will be on growth patterns and performance of the Ross hybrids as a modern broiler under small-scale and semi commercial management condition. Aspect of the environment such as age, type of feeds and feeding methods, housing, seasons, lighting and genotype will be taken into consideration. The result of the study will provide a realistic database for mathematical modeling of production response and guideline for management planning in small-scale and semi-commercial management condition. Also this result will be important to broiler breeders, to determine the suitability of the modern broiler to small-scale and semi commercial management conditions. The objective of the study was to evaluate the mathematical model that could describe the performance of broilers under the small-scale and semi-commercial management conditions.
- Full Text:
- Date Issued: 2002
- Authors: Prince, Siliga Hulisani
- Date: 2002
- Subjects: Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MTech (Agricultural Management)
- Identifier: vital:10963 , http://hdl.handle.net/10948/110 , Broilers (Chickens)
- Description: Introduction : World poultry meat consumption consists of three major segments: broilers, turkeys, and other poultry which includes spent egg layers, spent breeder hens/males, ducks, geese, guinea-fowl, pheasants, quail, ratites, ostriches and emus. Broilers clearly dominate the world poultry consumption contributing about 70 percent to the world poultry market. Turkeys account for about eight percent while other poultry provides the balance of 22 percent (Roenick, 1998). The world broiler industry has been, and continues to be a very dynamic industry. It has been typified with unprecedented growth in terms of production. In 1961, the world produced 6.5 billion broilers. By 1990, the total annual production was a little over 27 billion broilers and by 1996, total world production had grown to 35.3 billion (Van der Sluis., 1999). This represents a fivefold increase in 35 years, and it has not stopped growing since, with world production surpassed 38 billion in 1998 (Van der Sluis., 1999). In Africa the human population was estimated to be 819.9 million, while the total poultry population of the continent was estimated as 1.133 million chickens, 15 million ducks and seven million turkeys in 1998. Production scale being 1.781701 metric tones (MT) of hen eggs, 2.269000 MT of chickens’ meat, 32.824MT of turkey meat and 52.989MT of duck meat (Gueye, 2000). Commercial poultry products are also imported and exported. For example, 12.000 metric tons of poultry meat was estimated to have been exported from South Africa in 1999, whereas 87.000 and 10.000 metric tons of poultry meat was imported into South Africa and Egypt, respectively (Gueye, 2000). In South Africa poultry production is moving toward the 21st century with the potential for increased development being greater than any other sector of the agricultural industry. The small-scale to medium-scale or semi-commercial farmer is becoming a role-player that needs to be serviced by the poultry industry (Fourie, 2000). The industry will have to take up the challenges that are facing an entrepreneur starting with a poultry venture. The poultry industry has developed from a humble beginning at the turn of the century into a multi-million Rand enterprise where protein is provided through the commercial and small marketing sector (Fourie, 2000). Some of the larger commercial companies market three million birds per week. It is estimated that the commercial company sector is responsible for 75 to 85 percent of production and marketing of white meat in this country whereas the small-scale and medium-scale or semi commercial poultry production enterprises provide 20 to 25 percent of the white meat through the sales of slaughtered and live poultry sale to rural, peri-urban and urban settlements (Fourie., 2000). Small-scale and semi-commercial broiler production is developed by entrepreneurs who buy day-old chicks from the big commercial hatcheries, rear them to the age of five to eight weeks and sell them through a marketing network or small outlets. The small-scale consist of farmers who reared 100 t0 1000 chickens per batch and semi-commercial consist of farmers who reared 1000 to 5000 chickens per batch. These types of farmers acquire very little technical backup in terms of a training and services center where assistance is available every day of the week. The broiler industry requires birds that are of commercial crosses selected for their ability to grow very fast and produce a good quality carcass in the shortest time frame. The small farmers purchase broiler stock, as the day-old chicks from commercial hatcheries and reared them up to six to eight weeks before slaughtered or sold as live chickens. The selling of live chickens through a network outlets system is becoming an industry that is growing at a steady pace, as household food security is becoming important to communities (Fourie, 2000). The price of feed is the single most expensive item on the list of expenses of a farmer because of their financial constraints. The small-scale and semicommercial broiler farmer is faced with the problem of buying small quantities of feed at an inflated price. The problem can be alleviated by groups of small farmers joining co-operative and buying feeds in bulk from suppliers and redistributing to small farmers. The community co-operative can once again play a major role in the distribution of small amounts of feed to its member. The biggest challenge is to provide training with a “hands on” approach. It will be ideal to have a training center where small farmers can be trained in all aspects of poultry production. The training facility will have to operate as a fully operational poultry unit with no risks to bio-security of a commercial enterprise. Training will have to be provided in aspects like hatchery, housing, broilers and record management depending on the farmer’s needs. There is also a need for the research on broiler performance under small-scale and semi commercial farming. Research in this sector of poultry production should look in appropriate feeds, feeding, technology, genotype and performance of genotypes under the system. Emphasis in this study will be on growth patterns and performance of the Ross hybrids as a modern broiler under small-scale and semi commercial management condition. Aspect of the environment such as age, type of feeds and feeding methods, housing, seasons, lighting and genotype will be taken into consideration. The result of the study will provide a realistic database for mathematical modeling of production response and guideline for management planning in small-scale and semi-commercial management condition. Also this result will be important to broiler breeders, to determine the suitability of the modern broiler to small-scale and semi commercial management conditions. The objective of the study was to evaluate the mathematical model that could describe the performance of broilers under the small-scale and semi-commercial management conditions.
- Full Text:
- Date Issued: 2002
Modelling the distribution and abundance of several demersal fish species on the Agulhas Bank, South Africa
- Authors: Sampson, Mark Robert
- Date: 2002
- Subjects: Fishes -- South Africa -- Geographical distribution , Fishes -- South Africa -- Geographical distribution -- Mathematical models
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5343 , http://hdl.handle.net/10962/d1006207 , Fishes -- South Africa -- Geographical distribution , Fishes -- South Africa -- Geographical distribution -- Mathematical models
- Description: The Agulhas Bank supports a speciose fish community, many of which are commercially important. Despite substantial research being conducted on aspects of their biology spatial aspects of their distribution and abundance in relation to environment parameters has been ignored. This study, therefore, addressed aspects related to the distribution and abundance of representative species on the Agulhas Bank within a Geographic Information System (GIS). Four candidate species were chosen due to their importance either in numbers or unit mass to the South African demersal trawl fishery. The species also shared morphological and taxonomic similarities. The candidate species chosen were the two Cape hake species, shallow-water hake Meluccius capensis, and deep-water hake Merluccius paradoxus, and the two pleuronectiform species being Agulhas sole Austroglossus pectoralis and redspotted tonguesole Cynoglossus zanzibarensis. The use of a GIS was appropriate and allowed for hidden spatial patterns be exposed and illustrated visually, while also facilitating the quantification of the relationships between distribution/abundance and certain environmental predictors using statistical methods The Department of Marine and Coastal Management, Cape Town, supplied biological data in the form of length frequency and biomass information from spring (AprillMay) and autumn (September/October) cruises conducted between 1986 and 1993 on the R. V. Africana. The Council for National Geoscience, Cape Town, supplied sediment data for the entire southern African coastline. Initial exploratory data analysis highlighted potential relationships between environmental variables and abundance for each specie's life-history stanzas. Variations in spatial distribution were found to be significantly different between each life-history stanzas within species. Fish density as a function of the additive effects of the various environmental parameters, including temperature, depth and sediment type, was assessed using a Poisson Generalized Additive Model (GAM), while distribution was analysed with a logistic GAM. A predictive logistic model was then created, taking into consideration the importance of the predictor variables for each species, allowing for predictive estimates to be made for each species by inputting environmental information within the study area. The importance of certain environmental variables influencing distribution and abundance were noted. General patterns indicated that sediment was the most important to both the distribution and abundance of the two pleuronectiform species and juvenile life-history stanzas, while the adult gadoids' distribution and abundance appeared to be depth dependent.
- Full Text:
- Date Issued: 2002
- Authors: Sampson, Mark Robert
- Date: 2002
- Subjects: Fishes -- South Africa -- Geographical distribution , Fishes -- South Africa -- Geographical distribution -- Mathematical models
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5343 , http://hdl.handle.net/10962/d1006207 , Fishes -- South Africa -- Geographical distribution , Fishes -- South Africa -- Geographical distribution -- Mathematical models
- Description: The Agulhas Bank supports a speciose fish community, many of which are commercially important. Despite substantial research being conducted on aspects of their biology spatial aspects of their distribution and abundance in relation to environment parameters has been ignored. This study, therefore, addressed aspects related to the distribution and abundance of representative species on the Agulhas Bank within a Geographic Information System (GIS). Four candidate species were chosen due to their importance either in numbers or unit mass to the South African demersal trawl fishery. The species also shared morphological and taxonomic similarities. The candidate species chosen were the two Cape hake species, shallow-water hake Meluccius capensis, and deep-water hake Merluccius paradoxus, and the two pleuronectiform species being Agulhas sole Austroglossus pectoralis and redspotted tonguesole Cynoglossus zanzibarensis. The use of a GIS was appropriate and allowed for hidden spatial patterns be exposed and illustrated visually, while also facilitating the quantification of the relationships between distribution/abundance and certain environmental predictors using statistical methods The Department of Marine and Coastal Management, Cape Town, supplied biological data in the form of length frequency and biomass information from spring (AprillMay) and autumn (September/October) cruises conducted between 1986 and 1993 on the R. V. Africana. The Council for National Geoscience, Cape Town, supplied sediment data for the entire southern African coastline. Initial exploratory data analysis highlighted potential relationships between environmental variables and abundance for each specie's life-history stanzas. Variations in spatial distribution were found to be significantly different between each life-history stanzas within species. Fish density as a function of the additive effects of the various environmental parameters, including temperature, depth and sediment type, was assessed using a Poisson Generalized Additive Model (GAM), while distribution was analysed with a logistic GAM. A predictive logistic model was then created, taking into consideration the importance of the predictor variables for each species, allowing for predictive estimates to be made for each species by inputting environmental information within the study area. The importance of certain environmental variables influencing distribution and abundance were noted. General patterns indicated that sediment was the most important to both the distribution and abundance of the two pleuronectiform species and juvenile life-history stanzas, while the adult gadoids' distribution and abundance appeared to be depth dependent.
- Full Text:
- Date Issued: 2002
Narratiewe strategieë by die ondersoek van die verlede in twee romans, naamlik Lijken op liefde (1997) deur Astrid H. Roemer en Duiwelskloof (1998) deur André P. Brink
- Authors: Potgieter, Maretha
- Date: 2002
- Subjects: Roemer, Astrid. Lijken op liefde , Brink, André Philippus, 1935- Duiwelskloof
- Language: Afrikaans
- Type: Thesis , Masters , MA
- Identifier: vital:3578 , http://hdl.handle.net/10962/d1002151 , Roemer, Astrid. Lijken op liefde , Brink, André Philippus, 1935- Duiwelskloof
- Description: This study investigates some of the narrative strategies used by two novels, namely Lijken op Liefde (1997) by the Surinam born author Astrid H. Roemer and Duiwelskloof (1998) by the South African André P. Brink, in their exploration of and dialogue with traumatic pasts. Both texts are written within so-called postcolonial time frames, delve into the personal and collective past and attempt to provide a corrective on knowledges that used to be deemed not useful, unimportant or have been forgotten by official historiography. The theoretical base of the study is an eclectic mixture of both postcolonial and postmodern theories, throwing light on the strategies employed by these novels in order to understand, problematise and creatively exploit the past. , Hierdie studie kyk na sommige van die narratiewe strategieë binne twee romans, naamlik Lijken op Liefde (1997) deur die Surinaams-gebore outeur Astrid H. Roemer en Duiwelskloof (1998) deur die Suid-Afrikaner André P. Brink, in hulle ondersoek na en dialoog met die traumatiese verlede. Beide tekste is geskryf binne sogenaamde postkoloniale tydvakke, delf in die persoonlike en kollektiewe verlede, en verskaf ’n korrektief op die dinge wat as onbruikbaar of onbelangrik beskou is, of vergete geraak het binne die offisiële historiografie. Die teoretiese basis van die studie is ’n eklektiese mengsel van beide postkoloniale en postmoderne teorieë wat lig werp op die strategieë wat hierdie tekste gebruik om die verlede te verstaan, te problematiseer en kreatief te ontgin.
- Full Text:
- Date Issued: 2002
- Authors: Potgieter, Maretha
- Date: 2002
- Subjects: Roemer, Astrid. Lijken op liefde , Brink, André Philippus, 1935- Duiwelskloof
- Language: Afrikaans
- Type: Thesis , Masters , MA
- Identifier: vital:3578 , http://hdl.handle.net/10962/d1002151 , Roemer, Astrid. Lijken op liefde , Brink, André Philippus, 1935- Duiwelskloof
- Description: This study investigates some of the narrative strategies used by two novels, namely Lijken op Liefde (1997) by the Surinam born author Astrid H. Roemer and Duiwelskloof (1998) by the South African André P. Brink, in their exploration of and dialogue with traumatic pasts. Both texts are written within so-called postcolonial time frames, delve into the personal and collective past and attempt to provide a corrective on knowledges that used to be deemed not useful, unimportant or have been forgotten by official historiography. The theoretical base of the study is an eclectic mixture of both postcolonial and postmodern theories, throwing light on the strategies employed by these novels in order to understand, problematise and creatively exploit the past. , Hierdie studie kyk na sommige van die narratiewe strategieë binne twee romans, naamlik Lijken op Liefde (1997) deur die Surinaams-gebore outeur Astrid H. Roemer en Duiwelskloof (1998) deur die Suid-Afrikaner André P. Brink, in hulle ondersoek na en dialoog met die traumatiese verlede. Beide tekste is geskryf binne sogenaamde postkoloniale tydvakke, delf in die persoonlike en kollektiewe verlede, en verskaf ’n korrektief op die dinge wat as onbruikbaar of onbelangrik beskou is, of vergete geraak het binne die offisiële historiografie. Die teoretiese basis van die studie is ’n eklektiese mengsel van beide postkoloniale en postmoderne teorieë wat lig werp op die strategieë wat hierdie tekste gebruik om die verlede te verstaan, te problematiseer en kreatief te ontgin.
- 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
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
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