The use of Van Hiele's theory to explore problems encountered in circle geometry: a grade 11 case study
- Authors: Siyepu, Sibawu Witness
- Date: 2005
- Subjects: Geometry -- Study and teaching (Secondary) -- South Africa Mathematics -- Study and teaching (Secondary) -- South Africa Mathematics teachers -- Training of -- South Africa Mathematical ability -- Testing
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1871 , http://hdl.handle.net/10962/d1004777
- Description: The research presented in this thesis is a case study located in the interpretive paradigm of qualitative research. The focus is on the use of van Hiele's theory to explore problems encountered in circle geometry by grade 11 learners and making some policy recommendations concerning the curriculum structure and teaching of the geometry at all grades. The interpretation is based to the learners' background in geometry i.e. their prior knowledge and experience of learning geometry. The study was carried out over a period of three years. The data collection process took a period of two months (April and May 2003) with a group of 21 grade 11 mathematics learners in a rural senior secondary school in the Eastern Cape. The researcher used document analysis, worksheets, participants' observation, van Hiele tests, a questionnaire and semi-structured interviews to collect data. The study showed that the structure of the South African geometry syllabus consists of a some what disorganized mixture of concepts. It is not sequential and hierarchical and it sequences concepts in a seemingly unrelated manner. The study revealed that the South African high school geometry curriculum is presented at a higher van Hiele level than what the learners can attain. The findings of the study showed that many of the grade 11 learners were under-prepared for the study of more sophisticated geometry concepts and proofs. Three categories of reasons could be ascribed to this: Firstly, there was insufficient preparation of learners during the primary and senior phases. Secondly the study indicated that there is overload of geometry at the high school level in the South African mathematics curriculum. Thirdly, the over-reliance on the traditional approach to teaching geometry, poor presentation of mathematical technical concepts and language problems, were identified as possible additional reasons for the poor learner understanding of geometry in general and circle geometry in particular. The study recommends that the structure of the South African geometry curriculum should be revisited and redesigned. Teachers should be empowered and developed to be more effective in teaching geometry through further studies in mathematics and in-service workshops. They should also be engaged in the process of implementing the van Hiele's theory in the teaching of geometry in their classrooms.
- Full Text:
- Date Issued: 2005
- Authors: Siyepu, Sibawu Witness
- Date: 2005
- Subjects: Geometry -- Study and teaching (Secondary) -- South Africa Mathematics -- Study and teaching (Secondary) -- South Africa Mathematics teachers -- Training of -- South Africa Mathematical ability -- Testing
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1871 , http://hdl.handle.net/10962/d1004777
- Description: The research presented in this thesis is a case study located in the interpretive paradigm of qualitative research. The focus is on the use of van Hiele's theory to explore problems encountered in circle geometry by grade 11 learners and making some policy recommendations concerning the curriculum structure and teaching of the geometry at all grades. The interpretation is based to the learners' background in geometry i.e. their prior knowledge and experience of learning geometry. The study was carried out over a period of three years. The data collection process took a period of two months (April and May 2003) with a group of 21 grade 11 mathematics learners in a rural senior secondary school in the Eastern Cape. The researcher used document analysis, worksheets, participants' observation, van Hiele tests, a questionnaire and semi-structured interviews to collect data. The study showed that the structure of the South African geometry syllabus consists of a some what disorganized mixture of concepts. It is not sequential and hierarchical and it sequences concepts in a seemingly unrelated manner. The study revealed that the South African high school geometry curriculum is presented at a higher van Hiele level than what the learners can attain. The findings of the study showed that many of the grade 11 learners were under-prepared for the study of more sophisticated geometry concepts and proofs. Three categories of reasons could be ascribed to this: Firstly, there was insufficient preparation of learners during the primary and senior phases. Secondly the study indicated that there is overload of geometry at the high school level in the South African mathematics curriculum. Thirdly, the over-reliance on the traditional approach to teaching geometry, poor presentation of mathematical technical concepts and language problems, were identified as possible additional reasons for the poor learner understanding of geometry in general and circle geometry in particular. The study recommends that the structure of the South African geometry curriculum should be revisited and redesigned. Teachers should be empowered and developed to be more effective in teaching geometry through further studies in mathematics and in-service workshops. They should also be engaged in the process of implementing the van Hiele's theory in the teaching of geometry in their classrooms.
- Full Text:
- Date Issued: 2005
Three perspectives on ukuthwasa: the view from traditional beliefs, western psychiatry and transpersonal psychology
- Authors: Booi, Beauty Ntombizanele
- Date: 2005
- Subjects: Healers -- South Africa , Divination -- South Africa , Schizophrenia -- Social aspects , Xhosa (African people) -- Psychology , Xhosa (African people) -- Social life and customs
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2936 , http://hdl.handle.net/10962/d1002445 , Healers -- South Africa , Divination -- South Africa , Schizophrenia -- Social aspects , Xhosa (African people) -- Psychology , Xhosa (African people) -- Social life and customs
- Description: Among the Xhosas, the healing sickness called intwaso is interptreted as a call by the ancestors to become a healer. Transpersonalists also see these initiatory illnesses as spiritual crises, while according to the widely accepted Western psychiatric view, illness is purely perceived in physical and psychological terms. A case study was conducted where a single participant who has undergone the process of ukuthwasa and is functioning as a traditional healer was interviewed. A series of interviews were done where information was gathered about significant experiences related to ukuthwasa process. Tapes were transcribed and a case narrative was written and interpreted using the traditional Xhosa beliefs, the western psychiatric and the transpersonal psychology perspectives. Strengths and weaknesses of each perspective were then examined.
- Full Text:
- Date Issued: 2005
- Authors: Booi, Beauty Ntombizanele
- Date: 2005
- Subjects: Healers -- South Africa , Divination -- South Africa , Schizophrenia -- Social aspects , Xhosa (African people) -- Psychology , Xhosa (African people) -- Social life and customs
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2936 , http://hdl.handle.net/10962/d1002445 , Healers -- South Africa , Divination -- South Africa , Schizophrenia -- Social aspects , Xhosa (African people) -- Psychology , Xhosa (African people) -- Social life and customs
- Description: Among the Xhosas, the healing sickness called intwaso is interptreted as a call by the ancestors to become a healer. Transpersonalists also see these initiatory illnesses as spiritual crises, while according to the widely accepted Western psychiatric view, illness is purely perceived in physical and psychological terms. A case study was conducted where a single participant who has undergone the process of ukuthwasa and is functioning as a traditional healer was interviewed. A series of interviews were done where information was gathered about significant experiences related to ukuthwasa process. Tapes were transcribed and a case narrative was written and interpreted using the traditional Xhosa beliefs, the western psychiatric and the transpersonal psychology perspectives. Strengths and weaknesses of each perspective were then examined.
- Full Text:
- Date Issued: 2005
Towards a better grasp of what matters in view of ‘the posts’
- O'Donoghue, Rob B, Lotz-Sisitka, Heila
- Authors: O'Donoghue, Rob B , Lotz-Sisitka, Heila
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182693 , vital:43854 , xlink:href="https://doi.org/10.1080/13504620500169593"
- Description: This response to McKenzie suggests that the issues of representivity, legitimacy and politics, inscribed within an institutional continuism characteristic of modernity within the McKenzie discourse, could well be recast within a reflexive view informed by insights derived with developing social theory. It briefly overviews the struggle for human agency that played out within the deconstructive engagements of the posts and probes how perspectives in social theory are opening the way for a break with features of environmental education as an institutional field. The review points to a reconstituting of the idea of environmental education research from scholastic field of/for environmental awareness and sustainable development, to a reflexive engagement within processes of social reproduction and reorientation in a changing world. A shift such as this would constitute a subtle change in a developing field of research, to situated design decisions of reflexive engagement (research) in social fields constituted within developing cultural contexts of risk.
- Full Text:
- Date Issued: 2005
- Authors: O'Donoghue, Rob B , Lotz-Sisitka, Heila
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/182693 , vital:43854 , xlink:href="https://doi.org/10.1080/13504620500169593"
- Description: This response to McKenzie suggests that the issues of representivity, legitimacy and politics, inscribed within an institutional continuism characteristic of modernity within the McKenzie discourse, could well be recast within a reflexive view informed by insights derived with developing social theory. It briefly overviews the struggle for human agency that played out within the deconstructive engagements of the posts and probes how perspectives in social theory are opening the way for a break with features of environmental education as an institutional field. The review points to a reconstituting of the idea of environmental education research from scholastic field of/for environmental awareness and sustainable development, to a reflexive engagement within processes of social reproduction and reorientation in a changing world. A shift such as this would constitute a subtle change in a developing field of research, to situated design decisions of reflexive engagement (research) in social fields constituted within developing cultural contexts of risk.
- Full Text:
- Date Issued: 2005
Towards a Classification of Intrusion Strength
- Motara, Yusuf M, Irwin, Barry V W
- Authors: Motara, Yusuf M , Irwin, Barry V W
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428261 , vital:72498 , https://www.researchgate.net/profile/Yusuf-Mota-ra/publication/267206150_Towards_a_Classification_of_Intru-sion_Strength/links/547485820cf245eb436de34e/Towards-a-Classification-of-Intrusion-Strength.pdf
- Description: This paper proposes a new term, “intrusion strength”, for use by the se-curity community and those affected by compromised systems. It justi-fies the usefulness of such a term, proposes a preliminary ranking of intrusion strength factors, and concludes by mentioning the work nec-essary to create a full taxonomy of intrusion strength.
- Full Text:
- Date Issued: 2005
- Authors: Motara, Yusuf M , Irwin, Barry V W
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428261 , vital:72498 , https://www.researchgate.net/profile/Yusuf-Mota-ra/publication/267206150_Towards_a_Classification_of_Intru-sion_Strength/links/547485820cf245eb436de34e/Towards-a-Classification-of-Intrusion-Strength.pdf
- Description: This paper proposes a new term, “intrusion strength”, for use by the se-curity community and those affected by compromised systems. It justi-fies the usefulness of such a term, proposes a preliminary ranking of intrusion strength factors, and concludes by mentioning the work nec-essary to create a full taxonomy of intrusion strength.
- Full Text:
- Date Issued: 2005
Towards an economic valuation of biodiversity: freshwater ecosystems
- Antrobus, Geoffrey G, Law, Matt
- Authors: Antrobus, Geoffrey G , Law, Matt
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143013 , vital:38185 , http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.620.4217andrep=rep1andtype=pdf
- Description: The valuation of environmental resources and biodiversity as a whole has become an increasingly necessary topic of research as our understanding of the importance and benefits of the healthy functioning of the environment develops. A major shortcoming of current research is that there has been very little advance in the valuation of freshwater biodiversity. The paper examines the socioeconomic importance of biodiversity and outlines the fundamentals of economic valuation thereof. The difficulties associated with the valuation of freshwater ecosystems are outlined and the results of a study presented to the South African Water Research Commission incorporating resource economics into freshwater quality objectives is described. The valuation of freshwater biodiversity is an important and complicated task that needs close attention in future research.
- Full Text:
- Date Issued: 2005
- Authors: Antrobus, Geoffrey G , Law, Matt
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143013 , vital:38185 , http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.620.4217andrep=rep1andtype=pdf
- Description: The valuation of environmental resources and biodiversity as a whole has become an increasingly necessary topic of research as our understanding of the importance and benefits of the healthy functioning of the environment develops. A major shortcoming of current research is that there has been very little advance in the valuation of freshwater biodiversity. The paper examines the socioeconomic importance of biodiversity and outlines the fundamentals of economic valuation thereof. The difficulties associated with the valuation of freshwater ecosystems are outlined and the results of a study presented to the South African Water Research Commission incorporating resource economics into freshwater quality objectives is described. The valuation of freshwater biodiversity is an important and complicated task that needs close attention in future research.
- Full Text:
- Date Issued: 2005
Towards an Infrastructural Framework for Secure Electronic Publication
- Forrester, Jock, Irwin, Barry V W
- Authors: Forrester, Jock , Irwin, Barry V W
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428274 , vital:72499 , https://d1wqtxts1xzle7.cloudfront.net/3456213/No_147_-_Forrester-libre.pdf?1390832679=andresponse-content-disposi-tion=inline%3B+filename%3DTowards_an_Infrastructural_Framework_for.pdfandExpires=1714791785andSignature=TY2i5fIQcyv493crTdmDaMEDLBmnqe-s1yjeJ4OAk~-Syb12yZ1EBj-cJi8jxrmIorji6THEB4kSon43fOBcA5XUwoZ0H1T~LooHIyiqhBymL2ZtszKbFdqu1zZCrCkfR1YYAjUiVaM2BNSyC-P-mtY6S5aFcwztHl43eogmS70AIt0x76p9gIvL3xQsyE-VXBrtOrbkbQweUmgZs80bQDMnS-oou481C0BJyp8y6St6BETLKCaJC~uPYzrHOG1CwVxNZQoz38zJ3pLIzuNmdLcrlts3BbASji3c53MY-CoEGflXljrvzG6f85EBo-Oy9kjyAzvJ9gZmfISayfA-~w__andKey-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: To prevent the accidental, or deliberate, publication of documents contain-ing hidden information the organisation needs to have an Electronic Publi-cation Policy, more importantly though, it needs to have the Technical Infra-structure in place to enforce the policy. This paper outlines such a Technical Infrastructure.
- Full Text:
- Date Issued: 2005
- Authors: Forrester, Jock , Irwin, Barry V W
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428274 , vital:72499 , https://d1wqtxts1xzle7.cloudfront.net/3456213/No_147_-_Forrester-libre.pdf?1390832679=andresponse-content-disposi-tion=inline%3B+filename%3DTowards_an_Infrastructural_Framework_for.pdfandExpires=1714791785andSignature=TY2i5fIQcyv493crTdmDaMEDLBmnqe-s1yjeJ4OAk~-Syb12yZ1EBj-cJi8jxrmIorji6THEB4kSon43fOBcA5XUwoZ0H1T~LooHIyiqhBymL2ZtszKbFdqu1zZCrCkfR1YYAjUiVaM2BNSyC-P-mtY6S5aFcwztHl43eogmS70AIt0x76p9gIvL3xQsyE-VXBrtOrbkbQweUmgZs80bQDMnS-oou481C0BJyp8y6St6BETLKCaJC~uPYzrHOG1CwVxNZQoz38zJ3pLIzuNmdLcrlts3BbASji3c53MY-CoEGflXljrvzG6f85EBo-Oy9kjyAzvJ9gZmfISayfA-~w__andKey-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: To prevent the accidental, or deliberate, publication of documents contain-ing hidden information the organisation needs to have an Electronic Publi-cation Policy, more importantly though, it needs to have the Technical Infra-structure in place to enforce the policy. This paper outlines such a Technical Infrastructure.
- Full Text:
- Date Issued: 2005
Towards the development of a protocol for rearing juvenile rock lobster, Jasus lalandii
- Authors: Esterhuizen, J. A
- Date: 2005
- Subjects: Lobsters -- Growth , Lobster fisheries -- South Africa , Crustacea -- Growth , Crustacea -- South Africa , Jasus lalandii , Lobster culture
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5328 , http://hdl.handle.net/10962/d1005174 , Lobsters -- Growth , Lobster fisheries -- South Africa , Crustacea -- Growth , Crustacea -- South Africa , Jasus lalandii , Lobster culture
- Description: The diversification of current aquaculture practise in South Africa is crucial for the future development of the industry. The rock lobster, Jasus lalandii has been identified as a possible candidate species for shore based culture in systems similar to those used for abalone farming. Reduced Total Allowable Catch (TAC's) and an increased minimum legal size were implemented as management strategies to relieve fishing pressure on natural stocks of J. lalandii, and in turn led to increased market demand and a possible niche for farmed lobsters. High puerulus settlement along the Namibian coast, together with other favourable aquaculture attributes, indicate that the commercial grow out of wild harvested juveniles could be feasible. The aim of study was to investigate the feasibility of growing out rock lobsters in shore based systems in Namibia and South Africa. The experimental objectives of the project were to investigate the nutritional requirements, as well as the effect of stocking density and tank design on growth and survival of J. lalandii. The economic viability of shore based rock lobster farming was then evaluated based on the experimental results and typical capital requirements of an abalone farm in South Africa. Puerulus and early juvenile rock lobsters were collected in Luderitz, Namibia and transported to HIK Abalone Farm in Hermanus, South Africa where they were acclimated in black fibre glass tanks in a flow through system. The pueruli were stocked at 50, 75, 100 and 125/m² and early juveniles at 20, 30, 40 and 50/m² to test the effect of density on growth and survival. A comparative dietary study with both size classes was conducted using a mussel diet (Choromytilus meridionalis and Mytilus galloprovincialis), a commercial shrimp feed diet and a rotational diet comprising both mussels and shrimp feed. Tanks provided with "v-shaped" asbestos hides, PVC hides and no hides were compared to test the effect on growth rate and survival of pueruli. All treatments were conducted in triplicate. Temperatures were recorded twice daily while water quality parameters were tested every second week. The results indicate that density had a significant effect on growth and survival on post-pueruli. An initial stocking density of 75 post-pueruli/m² is regarded as optimal both in terms of the growth rate and biomass production per tank. No differences in growth and survival rates were attained in the early juvenile size class. This indicates that higher densities can be used to rear juvenile J. lalandii. No significant differences were obtained in growth rate when reared under different hide conditions although asbestos hides yielded significantly higher survival rates (93.3 %) compared to the tanks provided with PVC hides (74.04 %) and no hides (77.8 %, p≤0.05). As a result of the high survival rate observed in tanks provided with "V-shaped" asbestos hides, these tanks also yielded higher biomass production per tank (297.8 grams) compared to the tanks provided with PVC hides and no hides (261.09 and 260.5 grams respectively). In the diet trials, growth rates of post pueruli and juvenile lobsters fed the mussel and rotational (mussel and shrimp feed) diets did not differ significantly, however, growth rates of lobsters fed the shrimp feed only diet was significantly lower than both the mussel and rotational diets (p≤0.05). Lobsters fed the mussel diet yielded significantly higher survival rates compared to lobsters fed either the rotational diet or shrimp feed diet only. An imbalance in the fatty acid profile of the shrimp feed could have been a major contributing factor to the poor growth and survival in lobsters fed the shrimp feed only diet as the level of linoleic acid (LOA) was exceptionally high resulting in a high (n -6):(n-3) ratio (1.01) compared to the mussel and rotational diets (0.17 and 0.56 respectively). The low level of arachidonic acid (ARA) in the shrimp feed diet could be a further contributing factor explaning for the poor growth and survival of juvenile rock lobsters. An economic feasibility study was conducted at the end of the experimental phase by modelling a hypothetical shore based rock lobster farm. A projection of production costs and revenues was based on the typical costs of a shore based abalone farm and the current market prices for wild harvested J. lalandii. The economic viability was evaluated using benefit-cost ratios, payback period, internal rate of return and breakeven analysis. Sensitivity analyses revealed that the projected lobster growth and survival rates were the main biological factors influencing the economic feasibility of the hypothetical rock lobster farm. An assumed four year grow out period at a low stocking density yielded more lucrative internal rate of return (IRR), benefit-cost ratio, payback period and net present values (NPV) than a five year grow out period at a high density. The four year grow out scenario proved to be more robust to the fluctuating Rand/US$ exchange rate and could accommodate a lower lobster survival rate. Results presented in this study indicate that rock lobster farming is a marginal commercial prospect based on current production performance and costs. Further research to develop effective puerulus collection techniques as well as to make lobster grow out technology more cost effective is required.
- Full Text:
- Date Issued: 2005
- Authors: Esterhuizen, J. A
- Date: 2005
- Subjects: Lobsters -- Growth , Lobster fisheries -- South Africa , Crustacea -- Growth , Crustacea -- South Africa , Jasus lalandii , Lobster culture
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5328 , http://hdl.handle.net/10962/d1005174 , Lobsters -- Growth , Lobster fisheries -- South Africa , Crustacea -- Growth , Crustacea -- South Africa , Jasus lalandii , Lobster culture
- Description: The diversification of current aquaculture practise in South Africa is crucial for the future development of the industry. The rock lobster, Jasus lalandii has been identified as a possible candidate species for shore based culture in systems similar to those used for abalone farming. Reduced Total Allowable Catch (TAC's) and an increased minimum legal size were implemented as management strategies to relieve fishing pressure on natural stocks of J. lalandii, and in turn led to increased market demand and a possible niche for farmed lobsters. High puerulus settlement along the Namibian coast, together with other favourable aquaculture attributes, indicate that the commercial grow out of wild harvested juveniles could be feasible. The aim of study was to investigate the feasibility of growing out rock lobsters in shore based systems in Namibia and South Africa. The experimental objectives of the project were to investigate the nutritional requirements, as well as the effect of stocking density and tank design on growth and survival of J. lalandii. The economic viability of shore based rock lobster farming was then evaluated based on the experimental results and typical capital requirements of an abalone farm in South Africa. Puerulus and early juvenile rock lobsters were collected in Luderitz, Namibia and transported to HIK Abalone Farm in Hermanus, South Africa where they were acclimated in black fibre glass tanks in a flow through system. The pueruli were stocked at 50, 75, 100 and 125/m² and early juveniles at 20, 30, 40 and 50/m² to test the effect of density on growth and survival. A comparative dietary study with both size classes was conducted using a mussel diet (Choromytilus meridionalis and Mytilus galloprovincialis), a commercial shrimp feed diet and a rotational diet comprising both mussels and shrimp feed. Tanks provided with "v-shaped" asbestos hides, PVC hides and no hides were compared to test the effect on growth rate and survival of pueruli. All treatments were conducted in triplicate. Temperatures were recorded twice daily while water quality parameters were tested every second week. The results indicate that density had a significant effect on growth and survival on post-pueruli. An initial stocking density of 75 post-pueruli/m² is regarded as optimal both in terms of the growth rate and biomass production per tank. No differences in growth and survival rates were attained in the early juvenile size class. This indicates that higher densities can be used to rear juvenile J. lalandii. No significant differences were obtained in growth rate when reared under different hide conditions although asbestos hides yielded significantly higher survival rates (93.3 %) compared to the tanks provided with PVC hides (74.04 %) and no hides (77.8 %, p≤0.05). As a result of the high survival rate observed in tanks provided with "V-shaped" asbestos hides, these tanks also yielded higher biomass production per tank (297.8 grams) compared to the tanks provided with PVC hides and no hides (261.09 and 260.5 grams respectively). In the diet trials, growth rates of post pueruli and juvenile lobsters fed the mussel and rotational (mussel and shrimp feed) diets did not differ significantly, however, growth rates of lobsters fed the shrimp feed only diet was significantly lower than both the mussel and rotational diets (p≤0.05). Lobsters fed the mussel diet yielded significantly higher survival rates compared to lobsters fed either the rotational diet or shrimp feed diet only. An imbalance in the fatty acid profile of the shrimp feed could have been a major contributing factor to the poor growth and survival in lobsters fed the shrimp feed only diet as the level of linoleic acid (LOA) was exceptionally high resulting in a high (n -6):(n-3) ratio (1.01) compared to the mussel and rotational diets (0.17 and 0.56 respectively). The low level of arachidonic acid (ARA) in the shrimp feed diet could be a further contributing factor explaning for the poor growth and survival of juvenile rock lobsters. An economic feasibility study was conducted at the end of the experimental phase by modelling a hypothetical shore based rock lobster farm. A projection of production costs and revenues was based on the typical costs of a shore based abalone farm and the current market prices for wild harvested J. lalandii. The economic viability was evaluated using benefit-cost ratios, payback period, internal rate of return and breakeven analysis. Sensitivity analyses revealed that the projected lobster growth and survival rates were the main biological factors influencing the economic feasibility of the hypothetical rock lobster farm. An assumed four year grow out period at a low stocking density yielded more lucrative internal rate of return (IRR), benefit-cost ratio, payback period and net present values (NPV) than a five year grow out period at a high density. The four year grow out scenario proved to be more robust to the fluctuating Rand/US$ exchange rate and could accommodate a lower lobster survival rate. Results presented in this study indicate that rock lobster farming is a marginal commercial prospect based on current production performance and costs. Further research to develop effective puerulus collection techniques as well as to make lobster grow out technology more cost effective is required.
- Full Text:
- Date Issued: 2005
Towards the development of a protocol for the selection of probiotics in marine fish larviculture
- Authors: Vine, Niall Gordon
- Date: 2005
- Subjects: Marine fishes -- Larvae Bacteria Fishes -- Microbiology Fish culture
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5329 , http://hdl.handle.net/10962/d1005175
- Description: Manipulation or control of the microbiological aquaculture environment has been identified as an important focus area for future hatchery development. Subsequently, alternatives to obtain control of the microbiological environment are being sought of which the field of probiotics appears highly promising. Probiotics are usually selected based on various in vitro characteristics, however, the methods used differ and are sometimes unsuccessful due to poor experimentation. The aim of this work is to contribute towards the development of a protocol for the in vitro screening of bacterial candidate probiotics for marine fish larviculture. To reduce the number of candidate probiotics to be tested in vivo, various in vitro experiments need to be conducted, each screening for a particular mode of action – antagonism towards pathogen through production of antimicrobial compounds, growth and attachment to fish intestinal mucus, and the production of other beneficial compounds such as vitamins, fatty-acids and digestive enzymes. A total of 108 bacteria species were isolated from the digestive tract of the adult common clownfish, Amphiprion percula to screen for potential probiotics to be used in clownfish larval rearing. The antagonistic compounds assay identified twelve isolates which showed antagonism towards two or more aquatic pathogens. This was followed by an in vitro test that involved growing the organisms in fish intestinal mucus and modeling their growth parameters. A ranking index (RI) was developed using the lag period (λ) and doubling time (td) of the organism, where (1over λ x td) x 100. Five candidate probionts (AP1-AP5) with varied growth parameters were used for further in vitro experiments. The attachment to mucus assay introduced a novel tool for quantifying competition for attachment sites between candidate probionts and pathogens on mucus. Candidate probiont Pseudoalteromonas AP5 reduced the attachment ability of Vibrio alginolyticus when added before the pathogen and partially out-competed the pathogen for attachment sites when added second. In vitro screening for the production of beneficial compounds tested the candidate probiotics’ ability to produce digestive enzymes - trypsin, lipase and alkaline phosphatase as well as carotenoids and vitamin C. Candidate probiont Pseudoalteromonas AP5 produced high levels of the enzymes (98.2, 34.1 and 91.3 mU product liberated.ml⁻¹, respectively) and contained carotenoids while Kocuria AP4 contained carotenoids but produced low quantities of enzymes (7.8, 0 and 59 mU product liberated.ml⁻¹, respectively). None of the candidate probiotics produced vitamin C. To eliminate potential pathogenic or toxic candidate probionts, Artemia nauplii were exposed to each candidate probiont and the percentage Artemia mortality after 24-hours was determined. Candidate probiont AP2 caused high mortality of Artemia nauplii (98.4%) and was excluded from further studies. Identification of candidate probionts AP3-AP5 was performed using 16S-rDNA molecular techniques and the bacteria were assigned the names Bacillus AP3, Kocuria AP4 and Pseudoalteromonas AP5, respectively. Two methods of larval probiont delivery were tested – attachment to Artemia, and in-water delivery. Attachment to Artemia was high for both Kocuria AP4 and Pseudoalteromonas AP5 (7.2 x10³ and 2.7x10⁴ bacteria.nauplius⁻¹, respectively) while the in-water viability experiment showed that Kocuria AP4 comprised 23.9% of the total culturable water microflora after 24 hours while Pseudoalteromonas AP5 contributed 100%. To validate the findings from the in vitro experiments, in vivo trials using clownfish larvae were performed. Of the four candidate probiotics tested, only Kocuria AP4 showed potential to increase larval survival. In vitro tests produced a better understanding of the possible mode of action and strategies of competition between bacteria, however, the number of criteria in which a candidate probiont is successful in vitro may not be the best predictor for its effectiveness in vivo. Commercial studies that reduce between-treatment variation are required to test predictions about the most suitable probiont or combinations thereof.
- Full Text:
- Date Issued: 2005
- Authors: Vine, Niall Gordon
- Date: 2005
- Subjects: Marine fishes -- Larvae Bacteria Fishes -- Microbiology Fish culture
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5329 , http://hdl.handle.net/10962/d1005175
- Description: Manipulation or control of the microbiological aquaculture environment has been identified as an important focus area for future hatchery development. Subsequently, alternatives to obtain control of the microbiological environment are being sought of which the field of probiotics appears highly promising. Probiotics are usually selected based on various in vitro characteristics, however, the methods used differ and are sometimes unsuccessful due to poor experimentation. The aim of this work is to contribute towards the development of a protocol for the in vitro screening of bacterial candidate probiotics for marine fish larviculture. To reduce the number of candidate probiotics to be tested in vivo, various in vitro experiments need to be conducted, each screening for a particular mode of action – antagonism towards pathogen through production of antimicrobial compounds, growth and attachment to fish intestinal mucus, and the production of other beneficial compounds such as vitamins, fatty-acids and digestive enzymes. A total of 108 bacteria species were isolated from the digestive tract of the adult common clownfish, Amphiprion percula to screen for potential probiotics to be used in clownfish larval rearing. The antagonistic compounds assay identified twelve isolates which showed antagonism towards two or more aquatic pathogens. This was followed by an in vitro test that involved growing the organisms in fish intestinal mucus and modeling their growth parameters. A ranking index (RI) was developed using the lag period (λ) and doubling time (td) of the organism, where (1over λ x td) x 100. Five candidate probionts (AP1-AP5) with varied growth parameters were used for further in vitro experiments. The attachment to mucus assay introduced a novel tool for quantifying competition for attachment sites between candidate probionts and pathogens on mucus. Candidate probiont Pseudoalteromonas AP5 reduced the attachment ability of Vibrio alginolyticus when added before the pathogen and partially out-competed the pathogen for attachment sites when added second. In vitro screening for the production of beneficial compounds tested the candidate probiotics’ ability to produce digestive enzymes - trypsin, lipase and alkaline phosphatase as well as carotenoids and vitamin C. Candidate probiont Pseudoalteromonas AP5 produced high levels of the enzymes (98.2, 34.1 and 91.3 mU product liberated.ml⁻¹, respectively) and contained carotenoids while Kocuria AP4 contained carotenoids but produced low quantities of enzymes (7.8, 0 and 59 mU product liberated.ml⁻¹, respectively). None of the candidate probiotics produced vitamin C. To eliminate potential pathogenic or toxic candidate probionts, Artemia nauplii were exposed to each candidate probiont and the percentage Artemia mortality after 24-hours was determined. Candidate probiont AP2 caused high mortality of Artemia nauplii (98.4%) and was excluded from further studies. Identification of candidate probionts AP3-AP5 was performed using 16S-rDNA molecular techniques and the bacteria were assigned the names Bacillus AP3, Kocuria AP4 and Pseudoalteromonas AP5, respectively. Two methods of larval probiont delivery were tested – attachment to Artemia, and in-water delivery. Attachment to Artemia was high for both Kocuria AP4 and Pseudoalteromonas AP5 (7.2 x10³ and 2.7x10⁴ bacteria.nauplius⁻¹, respectively) while the in-water viability experiment showed that Kocuria AP4 comprised 23.9% of the total culturable water microflora after 24 hours while Pseudoalteromonas AP5 contributed 100%. To validate the findings from the in vitro experiments, in vivo trials using clownfish larvae were performed. Of the four candidate probiotics tested, only Kocuria AP4 showed potential to increase larval survival. In vitro tests produced a better understanding of the possible mode of action and strategies of competition between bacteria, however, the number of criteria in which a candidate probiont is successful in vitro may not be the best predictor for its effectiveness in vivo. Commercial studies that reduce between-treatment variation are required to test predictions about the most suitable probiont or combinations thereof.
- Full Text:
- Date Issued: 2005
Training needs for municipal employees: a case study of Makana Municipality
- Authors: Hamaamba, Tyson
- Date: 2005
- Subjects: Municipal officials and employees -- Training of -- South Africa -- Grahamstown Environmental education -- South Africa -- Grahamstown Local officials and employees -- Training of -- South Africa -- Grahamstown Municipal water supply -- South Africa -- Grahamstown Sanitation -- South Africa -- Grahamstown Environmental health -- South Africa -- Grahamstown Environmental management -- South Africa -- Grahamstown Livestock -- Management -- South Africa -- Grahamstown Refuse and refuse disposal -- South Africa -- Grahamstown Fire departments -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1943 , http://hdl.handle.net/10962/d1007952
- Description: This study investigated the education and training needs for municipal employees in order to inform an education and training strategy that would address environmental management challenges in Makana local municipality in Grahamstown, Eastern Cape province. The research was conducted as a qualitative case study that made use of questionnaires, document analysis, focus group discussions and interviews as instruments for data generation. Samples of respondents were selected from Makana Municipality employees in top and middle management positions, professionals/technicians and workers, including elected councillors. The study was contextualised through establishing environmental management issues in Makana municipality; establishing organisational needs; development of a learner profile; and through a review of policies and recent trends in adult education. The study established that the Makana Municipality employees are most concerned with the following issues: sanitation; solid waste management; livestock management and fire management. These issues require primary environmental competences among all council employees (top and middle management, professionals and technicians, workers and councillors who work on part-time basis). The educational implications needed to respond to these issues also require an understanding of legislation. The study also established that technical education and training which includes planning, project management, and financial and budgeting competences are necessary amongst the management and professionals. These competences may enable them to develop capacity in environmental management. This study further established the need for social education which includes competences such as communication and social justice. These competences should be developed amongst members of the same group as they need to involve the community in management of the environment. This should enable the municipality to create job opportunities and help change negative attitudes.
- Full Text:
- Date Issued: 2005
- Authors: Hamaamba, Tyson
- Date: 2005
- Subjects: Municipal officials and employees -- Training of -- South Africa -- Grahamstown Environmental education -- South Africa -- Grahamstown Local officials and employees -- Training of -- South Africa -- Grahamstown Municipal water supply -- South Africa -- Grahamstown Sanitation -- South Africa -- Grahamstown Environmental health -- South Africa -- Grahamstown Environmental management -- South Africa -- Grahamstown Livestock -- Management -- South Africa -- Grahamstown Refuse and refuse disposal -- South Africa -- Grahamstown Fire departments -- South Africa -- Grahamstown
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1943 , http://hdl.handle.net/10962/d1007952
- Description: This study investigated the education and training needs for municipal employees in order to inform an education and training strategy that would address environmental management challenges in Makana local municipality in Grahamstown, Eastern Cape province. The research was conducted as a qualitative case study that made use of questionnaires, document analysis, focus group discussions and interviews as instruments for data generation. Samples of respondents were selected from Makana Municipality employees in top and middle management positions, professionals/technicians and workers, including elected councillors. The study was contextualised through establishing environmental management issues in Makana municipality; establishing organisational needs; development of a learner profile; and through a review of policies and recent trends in adult education. The study established that the Makana Municipality employees are most concerned with the following issues: sanitation; solid waste management; livestock management and fire management. These issues require primary environmental competences among all council employees (top and middle management, professionals and technicians, workers and councillors who work on part-time basis). The educational implications needed to respond to these issues also require an understanding of legislation. The study also established that technical education and training which includes planning, project management, and financial and budgeting competences are necessary amongst the management and professionals. These competences may enable them to develop capacity in environmental management. This study further established the need for social education which includes competences such as communication and social justice. These competences should be developed amongst members of the same group as they need to involve the community in management of the environment. This should enable the municipality to create job opportunities and help change negative attitudes.
- Full Text:
- Date Issued: 2005
Trans-oceanic and endemic origins of the small minnow mayflies (Ephemeroptera, Baetidae) of Madagascar
- Monaghan, M T, Gattolliat, J L, Sartori, Michel, Elouard, J M, Barber-James, Helen M, Derleth, P, Glaizot, Olivier, de Moor, Ferdy C, Vogler, Alfred P
- Authors: Monaghan, M T , Gattolliat, J L , Sartori, Michel , Elouard, J M , Barber-James, Helen M , Derleth, P , Glaizot, Olivier , de Moor, Ferdy C , Vogler, Alfred P
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6957 , http://hdl.handle.net/10962/d1011998
- Description: We investigated the relative importance of dispersal and vicariance in forming the Madagascar insect fauna, sequencing approximately 2300bp from three rRNA gene regions to investigate the phylogeny of Afrotropical small minnow mayflies (Ephemeroptera: Baetidae). Six lineages contained trans-oceanic sister taxa, and variation in genetic divergence between sister taxa revealed relationships that range from very recent dispersal to ancient vicariance. Dispersal was most recent and frequent in species that spend the larval stage in standing water, adding to evidence that these evolutionarily unstable habitats may select for ecological traits that increase dispersal in insects. Ancestral state likelihood analysis suggested at least one Afrotropical lineage had its origin in Madagascar, demonstrating that unidirectional dispersal from a continental source may be too simplistic. We conclude that the Malagasy mayfly fauna should be considered in a biogeographical context that extends beyond Madagascar itself, encompassing trans-oceanic dispersal within multiple lineages.
- Full Text:
- Date Issued: 2005
- Authors: Monaghan, M T , Gattolliat, J L , Sartori, Michel , Elouard, J M , Barber-James, Helen M , Derleth, P , Glaizot, Olivier , de Moor, Ferdy C , Vogler, Alfred P
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6957 , http://hdl.handle.net/10962/d1011998
- Description: We investigated the relative importance of dispersal and vicariance in forming the Madagascar insect fauna, sequencing approximately 2300bp from three rRNA gene regions to investigate the phylogeny of Afrotropical small minnow mayflies (Ephemeroptera: Baetidae). Six lineages contained trans-oceanic sister taxa, and variation in genetic divergence between sister taxa revealed relationships that range from very recent dispersal to ancient vicariance. Dispersal was most recent and frequent in species that spend the larval stage in standing water, adding to evidence that these evolutionarily unstable habitats may select for ecological traits that increase dispersal in insects. Ancestral state likelihood analysis suggested at least one Afrotropical lineage had its origin in Madagascar, demonstrating that unidirectional dispersal from a continental source may be too simplistic. We conclude that the Malagasy mayfly fauna should be considered in a biogeographical context that extends beyond Madagascar itself, encompassing trans-oceanic dispersal within multiple lineages.
- Full Text:
- Date Issued: 2005
Transmitting rdf graph deltas for a cheaper semantic web
- Cloran, Russell, Irwin, Barry V W
- Authors: Cloran, Russell , Irwin, Barry V W
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428288 , vital:72500
- Description: The Resoure Description Format is set to become the format to fulfill the vision of the Semantic Web. If RDF is widely to be used as a data representation framework, it would be advantageous to support the transmission differences in RDF graphs, enabling small and therefore possibly more frequent updates. This paper discusses the tools re-quired to enable transmission of graph differences, and the work need-ed to complete this toolset.
- Full Text:
- Date Issued: 2005
- Authors: Cloran, Russell , Irwin, Barry V W
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428288 , vital:72500
- Description: The Resoure Description Format is set to become the format to fulfill the vision of the Semantic Web. If RDF is widely to be used as a data representation framework, it would be advantageous to support the transmission differences in RDF graphs, enabling small and therefore possibly more frequent updates. This paper discusses the tools re-quired to enable transmission of graph differences, and the work need-ed to complete this toolset.
- Full Text:
- Date Issued: 2005
Trauma, imagery and the therapeutic relationship : Langu's story
- Karpelowsky, Belinda J, Edwards, David J A
- Authors: Karpelowsky, Belinda J , Edwards, David J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6268 , http://hdl.handle.net/10962/d1008267
- Description: This paper, a phenomenological case study, describes the psychotherapy of Langu (pseudonym), a 21-year-old student, who presented with Acute Stress Disorder following a series of motor accidents that affected him and his family. Langu's most distressing experience was having to identify his brother's mutilated and severely burned body. Because of the intensity of the intrusive re-experiencing of traumatic imagery and the degree of dissociative numbing, Langu participated in four intensive guided imagery sessions, which involved reliving the incident, and imaginal dialogues with his dead brother. Session records and supervision notes from the therapy process that unfolded over 22 sessions served as the basis for a thematically selective case narrative. Additional material was obtained from several research interviews with Langu over the following months. The narrative highlights the impact of the imagery work as well as relational aspects of the therapy. The case narrative provides a source for examining many aspects of the psychological impact of trauma and the path to healing, as well as the dilemmas and challenges faced by therapists working with traumatised individuals.
- Full Text:
- Date Issued: 2005
- Authors: Karpelowsky, Belinda J , Edwards, David J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6268 , http://hdl.handle.net/10962/d1008267
- Description: This paper, a phenomenological case study, describes the psychotherapy of Langu (pseudonym), a 21-year-old student, who presented with Acute Stress Disorder following a series of motor accidents that affected him and his family. Langu's most distressing experience was having to identify his brother's mutilated and severely burned body. Because of the intensity of the intrusive re-experiencing of traumatic imagery and the degree of dissociative numbing, Langu participated in four intensive guided imagery sessions, which involved reliving the incident, and imaginal dialogues with his dead brother. Session records and supervision notes from the therapy process that unfolded over 22 sessions served as the basis for a thematically selective case narrative. Additional material was obtained from several research interviews with Langu over the following months. The narrative highlights the impact of the imagery work as well as relational aspects of the therapy. The case narrative provides a source for examining many aspects of the psychological impact of trauma and the path to healing, as well as the dilemmas and challenges faced by therapists working with traumatised individuals.
- Full Text:
- Date Issued: 2005
Trauma, resilience and vulnerability to PTSD : a review and clinical case analysis
- Edwards, David J A, Sakasa, P, Van Wyk, G
- Authors: Edwards, David J A , Sakasa, P , Van Wyk, G
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6230 , http://hdl.handle.net/10962/d1007780
- Description: This article begins with two case examples of a girl and an adolescent who were raped and developed chronic PTSD. These are used as a basis for understanding the role of a range of factors that are associated with resilience and vulnerability in the face of traumatic events. A literature review examines the proportion of individuals who develop PTSD following trauma and the factors associated with vulnerability and resilience. These include gender, developmental factors, social support and personality factors. Psychological factors associated with maintenance of chronic PTSD are also briefly reviewed. This material is used as a basis for reconsidering the case examples. Each case is formulated within a framework based on sources of vulnerability and qualities of resilience. Approaches to intervention are suggested that could address the range of factors making the individuals vulnerable to chronic psychological problems and support resiliency and recovery.
- Full Text:
- Date Issued: 2005
- Authors: Edwards, David J A , Sakasa, P , Van Wyk, G
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6230 , http://hdl.handle.net/10962/d1007780
- Description: This article begins with two case examples of a girl and an adolescent who were raped and developed chronic PTSD. These are used as a basis for understanding the role of a range of factors that are associated with resilience and vulnerability in the face of traumatic events. A literature review examines the proportion of individuals who develop PTSD following trauma and the factors associated with vulnerability and resilience. These include gender, developmental factors, social support and personality factors. Psychological factors associated with maintenance of chronic PTSD are also briefly reviewed. This material is used as a basis for reconsidering the case examples. Each case is formulated within a framework based on sources of vulnerability and qualities of resilience. Approaches to intervention are suggested that could address the range of factors making the individuals vulnerable to chronic psychological problems and support resiliency and recovery.
- Full Text:
- Date Issued: 2005
Treating PTSD in South African contexts : a theoretical framework and a model for developing evidence-based practice
- Authors: Edwards, David J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6231 , http://hdl.handle.net/10962/d1007781
- Description: Several psychological factors contribute to the development and maintenance of post-traumatic stress disorder (PTSD) because they interfere with the emotional processing of the traumatic event. These include problematic and painful emotions such as anxiety, shame, guilt and grief, distorted or dysfunctional cognitions, and cognitive, emotional, and behavioural avoidance mechanisms. Analysis of these maintaining factors provides the basis for current approaches to treatment which support traumatised individuals in facing emotional pain, working to resolve shame, grief and guilt, and expanding existing schemas to accommodate the traumatic event(s). Randomised controlled trials (RCTs) are reviewed in which the efficacy of some of these treatments have been evaluated. While many South African practitioners are familiar with current evidence-based approaches and are skilled at adapting them to local cultural and contextual conditions, a great deal still needs to be done to build a sound research base for local practice in the treatment of PTSD and disseminating that research to practitioners in the field. It is recommended that a case-based evaluation strategy be used to complement the findings of international RCT studies in order to build a foundation of locally contextualised and applicable scientific knowledge.
- Full Text:
- Date Issued: 2005
- Authors: Edwards, David J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6231 , http://hdl.handle.net/10962/d1007781
- Description: Several psychological factors contribute to the development and maintenance of post-traumatic stress disorder (PTSD) because they interfere with the emotional processing of the traumatic event. These include problematic and painful emotions such as anxiety, shame, guilt and grief, distorted or dysfunctional cognitions, and cognitive, emotional, and behavioural avoidance mechanisms. Analysis of these maintaining factors provides the basis for current approaches to treatment which support traumatised individuals in facing emotional pain, working to resolve shame, grief and guilt, and expanding existing schemas to accommodate the traumatic event(s). Randomised controlled trials (RCTs) are reviewed in which the efficacy of some of these treatments have been evaluated. While many South African practitioners are familiar with current evidence-based approaches and are skilled at adapting them to local cultural and contextual conditions, a great deal still needs to be done to build a sound research base for local practice in the treatment of PTSD and disseminating that research to practitioners in the field. It is recommended that a case-based evaluation strategy be used to complement the findings of international RCT studies in order to build a foundation of locally contextualised and applicable scientific knowledge.
- Full Text:
- Date Issued: 2005
Trust on the Web
- Cloran, Russell, Irwin, Barry V W
- Authors: Cloran, Russell , Irwin, Barry V W
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428900 , vital:72544 , https://digifors.cs.up.ac.za/issa/2005/Proceedings/Full/025_Article.pdf
- Description: This paper forms a backdrop for work investigating trust on the semantic web. With the mass of information currently available on the web, and the low barrier to entry for the publication of information on the web, it can be difficult to classify the au-thority of information found on the web. We use a case study of a suspected phish-ing scam in South Africa to examine the methods an advanced user may use to veri-fy the authenticity of a web site and the information it published. From this case study, we see that a website which is legitimate may easily appear to be a scam, because of the manner in which information is presented and the failure to use es-tablished industry best practices. We discuss a number of ways in which doubt may have been eliminated. We then discuss how a distributed trust system, as favoured by many researchers in trust on the semantic web, may have been implemented in this case to prove the authenticity of the site without the traditional means involv-ing the high cost of a digital certificate from a recognised Certificate Authority.
- Full Text:
- Date Issued: 2005
- Authors: Cloran, Russell , Irwin, Barry V W
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428900 , vital:72544 , https://digifors.cs.up.ac.za/issa/2005/Proceedings/Full/025_Article.pdf
- Description: This paper forms a backdrop for work investigating trust on the semantic web. With the mass of information currently available on the web, and the low barrier to entry for the publication of information on the web, it can be difficult to classify the au-thority of information found on the web. We use a case study of a suspected phish-ing scam in South Africa to examine the methods an advanced user may use to veri-fy the authenticity of a web site and the information it published. From this case study, we see that a website which is legitimate may easily appear to be a scam, because of the manner in which information is presented and the failure to use es-tablished industry best practices. We discuss a number of ways in which doubt may have been eliminated. We then discuss how a distributed trust system, as favoured by many researchers in trust on the semantic web, may have been implemented in this case to prove the authenticity of the site without the traditional means involv-ing the high cost of a digital certificate from a recognised Certificate Authority.
- Full Text:
- Date Issued: 2005
two cat boogie
- Authors: Berold, Robert
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , poem
- Identifier: http://hdl.handle.net/10962/462514 , vital:76310 , ISBN 0028-4459 , https://journals.co.za/doi/epdf/10.10520/EJC47772
- Description: New Coin is one of South Africa's most established and influential poetry journals. It publishes poetry, and poetry-related reviews, commentary and interviews. New Coin places a particular emphasis on evolving forms and experimental use of the English language in poetry in the South African context. In this sense it has traced the most exciting trends and currents in contemporary poetry in South Africa for a decade of more. The journal is published twice a year in June and December by the Institute for the Study of English in Africa (ISEA), Rhodes University.
- Full Text:
- Date Issued: 2005
- Authors: Berold, Robert
- Date: 2005
- Subjects: To be catalogued
- Language: English
- Type: text , poem
- Identifier: http://hdl.handle.net/10962/462514 , vital:76310 , ISBN 0028-4459 , https://journals.co.za/doi/epdf/10.10520/EJC47772
- Description: New Coin is one of South Africa's most established and influential poetry journals. It publishes poetry, and poetry-related reviews, commentary and interviews. New Coin places a particular emphasis on evolving forms and experimental use of the English language in poetry in the South African context. In this sense it has traced the most exciting trends and currents in contemporary poetry in South Africa for a decade of more. The journal is published twice a year in June and December by the Institute for the Study of English in Africa (ISEA), Rhodes University.
- Full Text:
- Date Issued: 2005
Unconscious influences on discourses about consciousness : ideology, state-specific science and unformulated experience
- Authors: Edwards, David J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6226 , http://hdl.handle.net/10962/d1007776
- Description: Discussions about consciousness are complicated by the fact that participants do not share a common underlying “ordinary” consciousness. Everyday experience is founded on what Teasdale calls implicational cognition, much of which is not verbally formulated. An unacknowledged aspect of debate is individuals’ attempts to negotiate the expression of their unformulated experience. This is further complicated by the way in which a discourse, based on particular ontological assumptions, exercises an ideological control which limits what underlying aspects of experience can be formulated at all. Tart’s concept of state specific sciences provides a framework within which the role of unformulated experience can be acknowledged and taken into account. Unless this is done, debates will be vitiated by participants engaging in ideological struggles and talking at cross-purposes.
- Full Text:
- Date Issued: 2005
- Authors: Edwards, David J A
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6226 , http://hdl.handle.net/10962/d1007776
- Description: Discussions about consciousness are complicated by the fact that participants do not share a common underlying “ordinary” consciousness. Everyday experience is founded on what Teasdale calls implicational cognition, much of which is not verbally formulated. An unacknowledged aspect of debate is individuals’ attempts to negotiate the expression of their unformulated experience. This is further complicated by the way in which a discourse, based on particular ontological assumptions, exercises an ideological control which limits what underlying aspects of experience can be formulated at all. Tart’s concept of state specific sciences provides a framework within which the role of unformulated experience can be acknowledged and taken into account. Unless this is done, debates will be vitiated by participants engaging in ideological struggles and talking at cross-purposes.
- Full Text:
- Date Issued: 2005
Understanding editorial independence and public accountability issues in public broadcasting service: a study of the editorial policies at the South African Broadcasting Corporation (SABC)
- Authors: Jjuuko, Denis Charles
- Date: 2005
- Subjects: South African Broadcasting Corporation , South African Broadcasting Corporation -- Law and legislation , Broadcasting -- Social aspects -- South Africa , Mass media -- Social aspects -- South Africa , Broadcasting policy -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3437 , http://hdl.handle.net/10962/d1002891 , South African Broadcasting Corporation , South African Broadcasting Corporation -- Law and legislation , Broadcasting -- Social aspects -- South Africa , Mass media -- Social aspects -- South Africa , Broadcasting policy -- South Africa
- Description: The concepts of editorial independence and public accountability are necessary in public broadcasting service as they help make a distinction between a public service broadcaster, a government and a commercial service broadcaster. This is because public service broadcasters are tasked with the responsibility of serving the interests of the general public. To do this, the above mentioned concepts have to be in place. This study examines these issues (editorial independence and public accountability) with reference to a case study of the editorial policies of the South African Broadcasting Corporation (SABC). Using public broadcasting theory, policy theory and qualitative research methods, the study examines the genesis of these editorial policies in 2003/2004 and how they provide the SABC with a means of balancing the tensions of editorial independence and public accountability. In analysing the SABC’s editorial policies, the study deals only with those policies whose principles are directly related to editorial independence and public accountability. Although some of these policies are found to be in line with public broadcasting service trends, others are found lacking. Various recommendations are made. The case study demonstrates the importance of an integrated and elaborated policy perspective in setting out how a public service broadcaster can manage editorial independence and public accountability. It also highlights the importance of using international ‘role models’ in ways that are appropriately adapted for the specific country concerned.
- Full Text:
- Date Issued: 2005
- Authors: Jjuuko, Denis Charles
- Date: 2005
- Subjects: South African Broadcasting Corporation , South African Broadcasting Corporation -- Law and legislation , Broadcasting -- Social aspects -- South Africa , Mass media -- Social aspects -- South Africa , Broadcasting policy -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3437 , http://hdl.handle.net/10962/d1002891 , South African Broadcasting Corporation , South African Broadcasting Corporation -- Law and legislation , Broadcasting -- Social aspects -- South Africa , Mass media -- Social aspects -- South Africa , Broadcasting policy -- South Africa
- Description: The concepts of editorial independence and public accountability are necessary in public broadcasting service as they help make a distinction between a public service broadcaster, a government and a commercial service broadcaster. This is because public service broadcasters are tasked with the responsibility of serving the interests of the general public. To do this, the above mentioned concepts have to be in place. This study examines these issues (editorial independence and public accountability) with reference to a case study of the editorial policies of the South African Broadcasting Corporation (SABC). Using public broadcasting theory, policy theory and qualitative research methods, the study examines the genesis of these editorial policies in 2003/2004 and how they provide the SABC with a means of balancing the tensions of editorial independence and public accountability. In analysing the SABC’s editorial policies, the study deals only with those policies whose principles are directly related to editorial independence and public accountability. Although some of these policies are found to be in line with public broadcasting service trends, others are found lacking. Various recommendations are made. The case study demonstrates the importance of an integrated and elaborated policy perspective in setting out how a public service broadcaster can manage editorial independence and public accountability. It also highlights the importance of using international ‘role models’ in ways that are appropriately adapted for the specific country concerned.
- Full Text:
- Date Issued: 2005
Unlocking the armour: enabling intrusion detection and analysis of encrypted traffic streams
- Authors: Irwin, Barry V W
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428845 , vital:72540
- Description: In the interests of maintaining end to end security, increasing volumes of information are being encrypted while in transit. Many organisations and users will make use of secure encrypted protocols for information interchange given an option. The very security that is provided by these transport protocols, such as IPSEC, HTTPS and SSH also acts against the security monitoring of an organisation’s traffic. Intrusion detection systems are no longer easily able to inspect the payload of encrypted protocols. Similarly these protocols can potentially be difficult for securi-ty and network administrators to debug, validate and analyse. This pa-per discusses the need for a means of a trusted third party being able to unpack encrypted data traversing a network and a proposes an ar-chitecture which would enable this to be achieved through the extrac-tion and sharing of the appropriate encipherment tokens, based on the assumption that an organisation has legitimate access to one side of a communication entering or exiting its network. This problem also has particular relevance to honey-net research and for investigators trying to perform real-time monitoring of an intruder which is making use of such a protected protocol. A proof of concept implementation of the proposed architecture is also discussed.
- Full Text:
- Date Issued: 2005
- Authors: Irwin, Barry V W
- Date: 2005
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428845 , vital:72540
- Description: In the interests of maintaining end to end security, increasing volumes of information are being encrypted while in transit. Many organisations and users will make use of secure encrypted protocols for information interchange given an option. The very security that is provided by these transport protocols, such as IPSEC, HTTPS and SSH also acts against the security monitoring of an organisation’s traffic. Intrusion detection systems are no longer easily able to inspect the payload of encrypted protocols. Similarly these protocols can potentially be difficult for securi-ty and network administrators to debug, validate and analyse. This pa-per discusses the need for a means of a trusted third party being able to unpack encrypted data traversing a network and a proposes an ar-chitecture which would enable this to be achieved through the extrac-tion and sharing of the appropriate encipherment tokens, based on the assumption that an organisation has legitimate access to one side of a communication entering or exiting its network. This problem also has particular relevance to honey-net research and for investigators trying to perform real-time monitoring of an intruder which is making use of such a protected protocol. A proof of concept implementation of the proposed architecture is also discussed.
- Full Text:
- Date Issued: 2005
Using a FreeBSD "cluster" to provide network services
- Authors: Siebörger, David
- Date: 2005
- Language: English
- Type: Conference paper
- Identifier: vital:6611 , http://hdl.handle.net/10962/d1009524
- Description: A presentation on how FreeBSD might be used in a load-balancing cluster, using work done at Rhodes University as a case study. Presented to a community of higher education IT practitioners in September 2005.
- Full Text:
- Date Issued: 2005
- Authors: Siebörger, David
- Date: 2005
- Language: English
- Type: Conference paper
- Identifier: vital:6611 , http://hdl.handle.net/10962/d1009524
- Description: A presentation on how FreeBSD might be used in a load-balancing cluster, using work done at Rhodes University as a case study. Presented to a community of higher education IT practitioners in September 2005.
- Full Text:
- Date Issued: 2005