Data quality in thermal summation development models for forensically important blowflies
- Richards, Cameron S, Villet, Martin H
- Authors: Richards, Cameron S , Villet, Martin H
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441889 , vital:73932 , https://doi.org/10.1111/j.1365-2915.2009.00819.x
- Description: To highlight some issues regarding data quality that are significant in estimating post‐mortem intervals (PMI) from maggots, the developmental constants of thermal summation models for development of Chrysomya megacephala Fabricius (Diptera: Calliphoridae) were calculated from incidental data gathered from 12 published studies, and from data generated specifically for the purpose in a single experiment. The focused experiment involved measuring the timing of five developmental landmarks at nine constant temperatures with a sampling resolution of 6–12 h, which is characteristic of other published studies. Combining data from different studies produced inconsistent results because of statistical noise introduced by (at least) disparities in temporal precision, descriptive statistics, geographical location and rearing diets. A robust experimental design to estimate a developmental model should involve at least six constant temperatures, starting at about 7°C above the relevant developmental zero (D0) and going almost to the upper critical temperature, and a temporal sampling interval with a relative precision of about 10%, which requires sampling about every 2 h until hatching, about every 3 h until first ecdysis and about every 6 h until second ecdysis.
- Full Text:
- Date Issued: 2009
- Authors: Richards, Cameron S , Villet, Martin H
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441889 , vital:73932 , https://doi.org/10.1111/j.1365-2915.2009.00819.x
- Description: To highlight some issues regarding data quality that are significant in estimating post‐mortem intervals (PMI) from maggots, the developmental constants of thermal summation models for development of Chrysomya megacephala Fabricius (Diptera: Calliphoridae) were calculated from incidental data gathered from 12 published studies, and from data generated specifically for the purpose in a single experiment. The focused experiment involved measuring the timing of five developmental landmarks at nine constant temperatures with a sampling resolution of 6–12 h, which is characteristic of other published studies. Combining data from different studies produced inconsistent results because of statistical noise introduced by (at least) disparities in temporal precision, descriptive statistics, geographical location and rearing diets. A robust experimental design to estimate a developmental model should involve at least six constant temperatures, starting at about 7°C above the relevant developmental zero (D0) and going almost to the upper critical temperature, and a temporal sampling interval with a relative precision of about 10%, which requires sampling about every 2 h until hatching, about every 3 h until first ecdysis and about every 6 h until second ecdysis.
- Full Text:
- Date Issued: 2009
De La Rey rides (yet) again : Afrikaner identity politics and nostalgia in post-apartheid South Africa
- Authors: Baines, Gary F
- Date: 2009
- Language: English
- Type: Conference paper
- Identifier: vital:6158 , http://hdl.handle.net/10962/d1007078
- Description: In 2006 a relatively unknown South African artist with the stage name Bok van Blerk released his debut album called “De la Rey”. The album included a music video of the title track that calls upon the legendary Boer War general to save the volk (people) from the wantonly destructive strategies of the British imperial forces: the scorched earth policy and the subsequent internment of women and children in concentration camps. The British justified such extreme – some would say ‘genocidal’ – strategies so as to prevent non-combatants from supporting the irregular Boer soldiers. Although he did not believe that the war could be won on account of the overwhelming odds that the Boer forces faced, De la Rey still fought to the bitter end. Needless to say, he was on the losing side.
- Full Text:
- Date Issued: 2009
- Authors: Baines, Gary F
- Date: 2009
- Language: English
- Type: Conference paper
- Identifier: vital:6158 , http://hdl.handle.net/10962/d1007078
- Description: In 2006 a relatively unknown South African artist with the stage name Bok van Blerk released his debut album called “De la Rey”. The album included a music video of the title track that calls upon the legendary Boer War general to save the volk (people) from the wantonly destructive strategies of the British imperial forces: the scorched earth policy and the subsequent internment of women and children in concentration camps. The British justified such extreme – some would say ‘genocidal’ – strategies so as to prevent non-combatants from supporting the irregular Boer soldiers. Although he did not believe that the war could be won on account of the overwhelming odds that the Boer forces faced, De la Rey still fought to the bitter end. Needless to say, he was on the losing side.
- Full Text:
- Date Issued: 2009
Decision making improvement by effectively utilising activity-based costing and activity-based management tools
- Authors: Palmer, Vivian Julian
- Date: 2009
- Subjects: Decision making , Thought and thinking
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8677 , http://hdl.handle.net/10948/1152 , Decision making , Thought and thinking
- Description: The aim of this study was to suggest ways to effectively utilise Activity-Based Costing and Activity-Based Managment within Eskom Transmission Southern Grid to improve decision making towards improved business and financial performance. The ultimate purpose was to assist managers and staff to implement ABC and ABM effectively for improved business and financial performance. The focus was on the following objective: To suggest ways to effectively utilise ABC & ABM within Eskom Transmission Southern Grid as to improve decision making and business financial performance. Given the selection of management tools available, instruments such as ABC and ABM are usually not implemented alone, but may be supported by one or more approaches. For this reason ABC and ABM are contrasted with several other popular instruments mentioned in the literature. The instruments are: • The value chain; • Continuous improvement; • The theory of constraints; and • Total quality management. Insight will be given to provide managers with more accurate information regarding maintenance for the Grid and tools in identifying critical bottlenecks. By applying the TOC, TQM and continuous improvement strategies, managers will be able to make improved decisions, leading to improved financial performance in the Eskom Transmission Southern Grid. iii The literature study revealed that ABC and ABM prove to be the cornerstone for informed decision making. Since organisations are highly dependent on quality information to make these informed decisions, ABC and ABM reorientate the organisation towards understanding and managing work processes thus impacting financial performance positively. ABC and ABM trace the cost of activities such as engineering and procurement to how maintenance benefits from these activities. The empirical study consisted of a structured questionnaire distributed to a sample population of engineers and managers in Eskom Transmission Southern Grid in Port Elizabeth. It was aimed at gathering information about the use of ABC and ABM within the Grid. Semi-structured interviews were also conducted with financial staff in the Grid and a focus group interview with engineering staff was done. The main findings of the empirical investigation revealed that management and staff lack insight into the use of ABC and ABM and how it can be integrated with existing improvement systems within the organisation. This study is concluded with a number of recommendations. These recommendations address the shortcomings and improvements that can be made to improve the utilisation of ABC and ABM within the organisation. The recommendations address the following: • Ensuring full commitment towards organisational goals and broadening the endorsement of ABC within the organisation; • Highlighting the importance of financial performance throughout the Grid; • Training of Managers, finance staff and engineers is required for proper execution of the ABC system; • Implementers need skills and know-how of the ABC and ABM system ensuring full utilisation; • The main cost drivers are identified, prioritised and efforts channelled into these activities; • Tools such as the Theory Of Constraints and Total Quality Management from the proposed model would assist the Grid in identifying the bottlenecks of a system correctly, thus know explicitly the amount of slack capacity of each activity available during a specific time period.
- Full Text:
- Date Issued: 2009
- Authors: Palmer, Vivian Julian
- Date: 2009
- Subjects: Decision making , Thought and thinking
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8677 , http://hdl.handle.net/10948/1152 , Decision making , Thought and thinking
- Description: The aim of this study was to suggest ways to effectively utilise Activity-Based Costing and Activity-Based Managment within Eskom Transmission Southern Grid to improve decision making towards improved business and financial performance. The ultimate purpose was to assist managers and staff to implement ABC and ABM effectively for improved business and financial performance. The focus was on the following objective: To suggest ways to effectively utilise ABC & ABM within Eskom Transmission Southern Grid as to improve decision making and business financial performance. Given the selection of management tools available, instruments such as ABC and ABM are usually not implemented alone, but may be supported by one or more approaches. For this reason ABC and ABM are contrasted with several other popular instruments mentioned in the literature. The instruments are: • The value chain; • Continuous improvement; • The theory of constraints; and • Total quality management. Insight will be given to provide managers with more accurate information regarding maintenance for the Grid and tools in identifying critical bottlenecks. By applying the TOC, TQM and continuous improvement strategies, managers will be able to make improved decisions, leading to improved financial performance in the Eskom Transmission Southern Grid. iii The literature study revealed that ABC and ABM prove to be the cornerstone for informed decision making. Since organisations are highly dependent on quality information to make these informed decisions, ABC and ABM reorientate the organisation towards understanding and managing work processes thus impacting financial performance positively. ABC and ABM trace the cost of activities such as engineering and procurement to how maintenance benefits from these activities. The empirical study consisted of a structured questionnaire distributed to a sample population of engineers and managers in Eskom Transmission Southern Grid in Port Elizabeth. It was aimed at gathering information about the use of ABC and ABM within the Grid. Semi-structured interviews were also conducted with financial staff in the Grid and a focus group interview with engineering staff was done. The main findings of the empirical investigation revealed that management and staff lack insight into the use of ABC and ABM and how it can be integrated with existing improvement systems within the organisation. This study is concluded with a number of recommendations. These recommendations address the shortcomings and improvements that can be made to improve the utilisation of ABC and ABM within the organisation. The recommendations address the following: • Ensuring full commitment towards organisational goals and broadening the endorsement of ABC within the organisation; • Highlighting the importance of financial performance throughout the Grid; • Training of Managers, finance staff and engineers is required for proper execution of the ABC system; • Implementers need skills and know-how of the ABC and ABM system ensuring full utilisation; • The main cost drivers are identified, prioritised and efforts channelled into these activities; • Tools such as the Theory Of Constraints and Total Quality Management from the proposed model would assist the Grid in identifying the bottlenecks of a system correctly, thus know explicitly the amount of slack capacity of each activity available during a specific time period.
- Full Text:
- Date Issued: 2009
Deconstructing language myths: which languages of learning and teaching in South Africa
- Dalvit, Lorenzo, Murray, Sarah, Terzoli, Alfredo
- Authors: Dalvit, Lorenzo , Murray, Sarah , Terzoli, Alfredo
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431260 , vital:72759 , https://d1wqtxts1xzle7.cloudfront.net/91537059/Deconstructing_language_myths_which_languages_of_learning_and_teaching_in_South_Africa.sflb-libre.pdf?1664136385=response-content-disposi-tion=inline%3B+filename%3DDeconstructing_language_myths_which_lang.pdfExpires=1714984902Signature=dj35y~SObsQq0TnqD-oDUj3CX7lgNnKJcMAchC7rarU74xqfrMlVfOwi-MZrNZvWvpxyzquBsmr1veH-ggRVXQP7TX4eKQq3tXV-gJZg3xyo7QJoGwrGPTjC4btF2kNrVJc6TQulzuPFEz47GtjQ6Nint4SmE7A30EMUMd8j25KgCUdtzqwx9kjBs-niKu~z-pk-Xon5YOolMTepbOwNr9wKGj8JafblTdnFs-H8CZ-Et4BD2mYV3GxnR0QLfgawFgDYkOSZnYhkl6wFsXG~Euwlhcvtp0EgUOfP4id~Ov9hhA-rSQxl81X2Dh1BdMuT3GSsK6VNmO7TikSC7NeGlQ__Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: In this article we argue for the use of African languages as Languages of Learning and Teaching (LoLT) for native speakers of such language in South Africa. We believe that both public and academic debate is in-fluenced by a set of ‘language myths’: 1) only one language should be used; 2) the earlier one starts using English as LoLT, the better; 3) us-ing English as LoLT improves English proficiency. These myths be seen as a direct manifestation of Western hegemony, and English-functional arguments are often the terms of reference. We will try a dif-ferent approach by highlighting the advantages of using an African lan-guage (ie isiXhosa) as LoLT and, whenever possible, we will try to put English on the ‘defence stand’. The purpose of this paper is not to ad-vocate the substitution of English with an African language. We believe that bilingual education is the appropriate choice for South Africa, but in order to achieve full equality between English and the African lan-guages in education, arguments in support of the latter must be put forward proactively. With our paper, we hope to contribute to this new perspective.
- Full Text:
- Date Issued: 2009
- Authors: Dalvit, Lorenzo , Murray, Sarah , Terzoli, Alfredo
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/431260 , vital:72759 , https://d1wqtxts1xzle7.cloudfront.net/91537059/Deconstructing_language_myths_which_languages_of_learning_and_teaching_in_South_Africa.sflb-libre.pdf?1664136385=response-content-disposi-tion=inline%3B+filename%3DDeconstructing_language_myths_which_lang.pdfExpires=1714984902Signature=dj35y~SObsQq0TnqD-oDUj3CX7lgNnKJcMAchC7rarU74xqfrMlVfOwi-MZrNZvWvpxyzquBsmr1veH-ggRVXQP7TX4eKQq3tXV-gJZg3xyo7QJoGwrGPTjC4btF2kNrVJc6TQulzuPFEz47GtjQ6Nint4SmE7A30EMUMd8j25KgCUdtzqwx9kjBs-niKu~z-pk-Xon5YOolMTepbOwNr9wKGj8JafblTdnFs-H8CZ-Et4BD2mYV3GxnR0QLfgawFgDYkOSZnYhkl6wFsXG~Euwlhcvtp0EgUOfP4id~Ov9hhA-rSQxl81X2Dh1BdMuT3GSsK6VNmO7TikSC7NeGlQ__Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA
- Description: In this article we argue for the use of African languages as Languages of Learning and Teaching (LoLT) for native speakers of such language in South Africa. We believe that both public and academic debate is in-fluenced by a set of ‘language myths’: 1) only one language should be used; 2) the earlier one starts using English as LoLT, the better; 3) us-ing English as LoLT improves English proficiency. These myths be seen as a direct manifestation of Western hegemony, and English-functional arguments are often the terms of reference. We will try a dif-ferent approach by highlighting the advantages of using an African lan-guage (ie isiXhosa) as LoLT and, whenever possible, we will try to put English on the ‘defence stand’. The purpose of this paper is not to ad-vocate the substitution of English with an African language. We believe that bilingual education is the appropriate choice for South Africa, but in order to achieve full equality between English and the African lan-guages in education, arguments in support of the latter must be put forward proactively. With our paper, we hope to contribute to this new perspective.
- Full Text:
- Date Issued: 2009
Dedication of Jo'burg's new ring
- Authors: Lewis, Colin A
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6189 , http://hdl.handle.net/10962/d1012395 , http://www.ringingworld.co.uk
- Description: Five years of planning, fund raising and hard work came to fruition in November 2008 when Africa's newest ring of bells was dedicated, bringing the first part of the Jo'burg Project to a successful conclusion.
- Full Text:
- Date Issued: 2009
- Authors: Lewis, Colin A
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6189 , http://hdl.handle.net/10962/d1012395 , http://www.ringingworld.co.uk
- Description: Five years of planning, fund raising and hard work came to fruition in November 2008 when Africa's newest ring of bells was dedicated, bringing the first part of the Jo'burg Project to a successful conclusion.
- Full Text:
- Date Issued: 2009
Deployment and Extension of a Converged WiMAX/WiFi Network for Dwesa Community Area South Africa
- Ndlovu, N, Terzoli, Alfredo, Thinyane, Mamello
- Authors: Ndlovu, N , Terzoli, Alfredo , Thinyane, Mamello
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428479 , vital:72514 , https://citeseerx.ist.psu.edu/document?repid=rep1andtype=pdfanddoi=22468be0252776eabb9e015b51e8e5cf2855ca5f
- Description: As demand for new, reliable, flexible and relatively inexpensive internet access in marginalized rural areas in developing countries increases, there is a need to amalgamate broadband technologies such as WiMAX and WiFi so as to extend the coverage area. Consequently, this will en-able provision of high-speed mobile data and telecommunications ser-vices. This paper describes how WiMAX and WiFi can be merged to-gether, with VSAT technology offering backhaul internet connectivity to provide ever present broadband access. We also look at their respective network applications and how there are going to be used to help support ICT4D activities in these marginalized areas.
- Full Text:
- Date Issued: 2009
- Authors: Ndlovu, N , Terzoli, Alfredo , Thinyane, Mamello
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428479 , vital:72514 , https://citeseerx.ist.psu.edu/document?repid=rep1andtype=pdfanddoi=22468be0252776eabb9e015b51e8e5cf2855ca5f
- Description: As demand for new, reliable, flexible and relatively inexpensive internet access in marginalized rural areas in developing countries increases, there is a need to amalgamate broadband technologies such as WiMAX and WiFi so as to extend the coverage area. Consequently, this will en-able provision of high-speed mobile data and telecommunications ser-vices. This paper describes how WiMAX and WiFi can be merged to-gether, with VSAT technology offering backhaul internet connectivity to provide ever present broadband access. We also look at their respective network applications and how there are going to be used to help support ICT4D activities in these marginalized areas.
- Full Text:
- Date Issued: 2009
Deriving value from IT investments within botique hotels: a Buffalo City case study
- Authors: Mathe, Thabelang
- Date: 2009
- Subjects: Information technology , Hotels -- Finance , Boardinghouses -- Finance , Small business -- South Africa -- Eastern Cape , Small business -- Finance
- Language: English
- Type: Thesis , Masters , MCom (Information Systems)
- Identifier: vital:11134 , http://hdl.handle.net/10353/d1000975 , Information technology , Hotels -- Finance , Boardinghouses -- Finance , Small business -- South Africa -- Eastern Cape , Small business -- Finance
- Description: Even though many organizations invest in IT, the value that IT is expected to contribute is still not clearly understood. Researchers agree that IT has become a crucial element to business operations and business existence. However, while there is continued investment in new information technologies and systems, organizations are not certain whether significant value is derived from IT investments. The failure to realize good return on IT investments is ascribed to a lack of understanding of IT by organizations and also the failure by organizations to align IT strategies with business strategies. The lack of alignment leads to the failure to match the right IT to the correct task, which leads to the poor application of systems and poor allocation of human resources to tasks. Therefore, organizations such as Small and Medium Enterprises (SMEs) in particular Boutique Hotels, are noted for their failure to derive better IT value. Their unique characteristics are understood to be influential in the way IT is used and managed by affecting the delivery of value from technology. In order to enable Boutique Hotels to derive more value from IT, the IT governance frameworks, Val IT and CobiT (ITGI, 2007), were examined as these integrate good practices to ensure that an organization‘s IT supports the business objectives. In addition, the Task Technology Fit (TTF) (Goodhue and Thompson, 1995) and Gap Analysis (Heeks, 2001) theories were highlighted as these prescribe the platform ideal for more value to be derived from IT. The current status of Boutique Hotels in Buffalo City was assessed through the use of questionnaires and interviews. The collected data was analyzed and resulted in the development of a model that can be used by Boutique Hotels in order to derive more value from IT and to maximize the use of IT.
- Full Text:
- Date Issued: 2009
- Authors: Mathe, Thabelang
- Date: 2009
- Subjects: Information technology , Hotels -- Finance , Boardinghouses -- Finance , Small business -- South Africa -- Eastern Cape , Small business -- Finance
- Language: English
- Type: Thesis , Masters , MCom (Information Systems)
- Identifier: vital:11134 , http://hdl.handle.net/10353/d1000975 , Information technology , Hotels -- Finance , Boardinghouses -- Finance , Small business -- South Africa -- Eastern Cape , Small business -- Finance
- Description: Even though many organizations invest in IT, the value that IT is expected to contribute is still not clearly understood. Researchers agree that IT has become a crucial element to business operations and business existence. However, while there is continued investment in new information technologies and systems, organizations are not certain whether significant value is derived from IT investments. The failure to realize good return on IT investments is ascribed to a lack of understanding of IT by organizations and also the failure by organizations to align IT strategies with business strategies. The lack of alignment leads to the failure to match the right IT to the correct task, which leads to the poor application of systems and poor allocation of human resources to tasks. Therefore, organizations such as Small and Medium Enterprises (SMEs) in particular Boutique Hotels, are noted for their failure to derive better IT value. Their unique characteristics are understood to be influential in the way IT is used and managed by affecting the delivery of value from technology. In order to enable Boutique Hotels to derive more value from IT, the IT governance frameworks, Val IT and CobiT (ITGI, 2007), were examined as these integrate good practices to ensure that an organization‘s IT supports the business objectives. In addition, the Task Technology Fit (TTF) (Goodhue and Thompson, 1995) and Gap Analysis (Heeks, 2001) theories were highlighted as these prescribe the platform ideal for more value to be derived from IT. The current status of Boutique Hotels in Buffalo City was assessed through the use of questionnaires and interviews. The collected data was analyzed and resulted in the development of a model that can be used by Boutique Hotels in order to derive more value from IT and to maximize the use of IT.
- Full Text:
- Date Issued: 2009
Detecting changes in elephant body condition in relation to resource quality
- Authors: De Klerk, Christelle
- Date: 2009
- Subjects: Elephants -- Nutrition -- South Africa -- Eastern Cape , Elephants -- Habitat -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10704 , http://hdl.handle.net/10948/939 , Elephants -- Nutrition -- South Africa -- Eastern Cape , Elephants -- Habitat -- South Africa -- Eastern Cape
- Description: Elephants, as megaherbivores, are known to have extensive impacts on vegetation, especially in enclosed areas. This raises the issue that elephants in enclosed areas may become limited by resource availability. Resource limitation is generally expressed via density dependence, but elephants, due to their slow demography, may not be affected by initial changes in resource availability. This highlights the need for a more sensitive measure of resource limitation to allow for the detection of energy stress within a population before changes in vital rates occur. This study investigated visual changes in elephant body condition in relation to resource availability in a number of Eastern Cape reserves to assess whether body condition could be used to detect life stages, as well as seasons and sites which may be resource limited. Elephant life stages were divided into energy stressed (newly weaned calves, lactating females, and old females) and non-energy stressed classes (sub-adults and non-lactating females) to determine whether energy stressed life stages were more vulnerable to resource limitation. In the AENP it was found that lactating and old females exhibited significantly poorer body condition than non-energy stressed individuals, but that weaned calves had body conditions similar to non-energy stressed individuals. Comparisons between seasons revealed that all life stages exhibited better condition in winter than summer or spring, with lactating females showing little recovery of condition over time. Seasonal body conditions were correlated with rainfall recorded in the Addo Elephant National Park. Comparisons of elephant body condition between sites (n = 6) revealed that body condition varied across sites, with poorer body condition associated with areas of higher elephant density and low rainfall during the study period. Comparisons with faecal dietary quality data both between sites and seasons indicated that body condition also responded to changes in the availability of protein and neutral detergent fibre (NDF) of plant resources, with higher protein and lower values associated with better condition. Based on condition estimates of elephants occurring in the Addo Main Camp, it was established that this population is experiencing nutritional stress, with energy stressed individuals exhibiting the lowest body conditions. This was supported by dietary quality measures. Our findings suggest that elephant body condition is a good measure for detecting resource limitation, both within populations and between seasons, and that elephant body condition respond to relatively small changes in resource conditions, thus making it an effective measure for the detection of nutritional stress. Additionally, our findings show that energy stressed individuals, particularly lactating and old females are more vulnerable to resource limitation. This demonstrates the importance of monitoring these life stages for the detection of density dependence within populations. Finally, our data suggest that threshold values of faecal dietary quality may exist at which body condition within a population begins to deteriorate, making it possible to determine the condition of a population through values obtained in faecal samples.
- Full Text:
- Date Issued: 2009
- Authors: De Klerk, Christelle
- Date: 2009
- Subjects: Elephants -- Nutrition -- South Africa -- Eastern Cape , Elephants -- Habitat -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10704 , http://hdl.handle.net/10948/939 , Elephants -- Nutrition -- South Africa -- Eastern Cape , Elephants -- Habitat -- South Africa -- Eastern Cape
- Description: Elephants, as megaherbivores, are known to have extensive impacts on vegetation, especially in enclosed areas. This raises the issue that elephants in enclosed areas may become limited by resource availability. Resource limitation is generally expressed via density dependence, but elephants, due to their slow demography, may not be affected by initial changes in resource availability. This highlights the need for a more sensitive measure of resource limitation to allow for the detection of energy stress within a population before changes in vital rates occur. This study investigated visual changes in elephant body condition in relation to resource availability in a number of Eastern Cape reserves to assess whether body condition could be used to detect life stages, as well as seasons and sites which may be resource limited. Elephant life stages were divided into energy stressed (newly weaned calves, lactating females, and old females) and non-energy stressed classes (sub-adults and non-lactating females) to determine whether energy stressed life stages were more vulnerable to resource limitation. In the AENP it was found that lactating and old females exhibited significantly poorer body condition than non-energy stressed individuals, but that weaned calves had body conditions similar to non-energy stressed individuals. Comparisons between seasons revealed that all life stages exhibited better condition in winter than summer or spring, with lactating females showing little recovery of condition over time. Seasonal body conditions were correlated with rainfall recorded in the Addo Elephant National Park. Comparisons of elephant body condition between sites (n = 6) revealed that body condition varied across sites, with poorer body condition associated with areas of higher elephant density and low rainfall during the study period. Comparisons with faecal dietary quality data both between sites and seasons indicated that body condition also responded to changes in the availability of protein and neutral detergent fibre (NDF) of plant resources, with higher protein and lower values associated with better condition. Based on condition estimates of elephants occurring in the Addo Main Camp, it was established that this population is experiencing nutritional stress, with energy stressed individuals exhibiting the lowest body conditions. This was supported by dietary quality measures. Our findings suggest that elephant body condition is a good measure for detecting resource limitation, both within populations and between seasons, and that elephant body condition respond to relatively small changes in resource conditions, thus making it an effective measure for the detection of nutritional stress. Additionally, our findings show that energy stressed individuals, particularly lactating and old females are more vulnerable to resource limitation. This demonstrates the importance of monitoring these life stages for the detection of density dependence within populations. Finally, our data suggest that threshold values of faecal dietary quality may exist at which body condition within a population begins to deteriorate, making it possible to determine the condition of a population through values obtained in faecal samples.
- Full Text:
- Date Issued: 2009
Detection of contaminants in wool bales using nuclear techniques
- Authors: Rapakgadi, Jim
- Date: 2009
- Subjects: Wool scouring , Mohair , X-rays
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10448 , http://hdl.handle.net/10948/993 , Wool scouring , Mohair , X-rays
- Description: To improve the quality and the marketability of wool and mohair, it is important to encourage, ensure and preferable certify that the baled fibre is free of contaminants. Anything other than the fibre that is within the bale can be classified as contaminants; this may be in the form of metal and wooden objects, plastic materials, paints, and vegetable matter such as grass and seed. The internationally accepted method for detecting and classifying these contaminants are highly labour intensive and costly. The ultimate goal of the present research is to develop a non-invasive and nondestructive technique that can be used to detect contaminants, particularly plastic (polymer) materials within wool and mohair bales. Such a technique can be implemented in the wool industry and also could be applied to other fibres, such as cotton. The immediate objective of this study was to evaluate the capability and the limitation of X-rays as a technique to detect such contaminants. It was found that X-rays were suitable for detecting foreign objects, or contaminants, such as metals, but not for detecting plastic materials, such as polypropylene and polyethylene.
- Full Text:
- Date Issued: 2009
- Authors: Rapakgadi, Jim
- Date: 2009
- Subjects: Wool scouring , Mohair , X-rays
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10448 , http://hdl.handle.net/10948/993 , Wool scouring , Mohair , X-rays
- Description: To improve the quality and the marketability of wool and mohair, it is important to encourage, ensure and preferable certify that the baled fibre is free of contaminants. Anything other than the fibre that is within the bale can be classified as contaminants; this may be in the form of metal and wooden objects, plastic materials, paints, and vegetable matter such as grass and seed. The internationally accepted method for detecting and classifying these contaminants are highly labour intensive and costly. The ultimate goal of the present research is to develop a non-invasive and nondestructive technique that can be used to detect contaminants, particularly plastic (polymer) materials within wool and mohair bales. Such a technique can be implemented in the wool industry and also could be applied to other fibres, such as cotton. The immediate objective of this study was to evaluate the capability and the limitation of X-rays as a technique to detect such contaminants. It was found that X-rays were suitable for detecting foreign objects, or contaminants, such as metals, but not for detecting plastic materials, such as polypropylene and polyethylene.
- Full Text:
- Date Issued: 2009
Determinants of capital structure of small and medium enterprises in the Buffalo City Municipality Eastern Cape Province South Africa
- Authors: Rungani, Ellen Chenesai
- Date: 2009
- Subjects: Debt-to-equity ratio , Capital , Value , Business enterprises -- South Africa -- Eastern Cape , Small business -- South Africa -- Eastern Cape , Municipal government -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , M Com (Business Management)
- Identifier: vital:11317 , http://hdl.handle.net/10353/271 , Debt-to-equity ratio , Capital , Value , Business enterprises -- South Africa -- Eastern Cape , Small business -- South Africa -- Eastern Cape , Municipal government -- South Africa -- Eastern Cape
- Description: This study investigated the determinants of capital structure of small and medium enterprises (SMEs) in the Buffalo city municipality in the Eastern Cape Province of South Africa. The objectives of the study were, to ascertain whether the use of internal equity (retained profits) was positively or negatively related to the size, age and profitability of the firm. Furthermore the study examined if the use of external equity (capital from owners) was negatively or positively related to the age, size and profitability of the firm. Finally the study wanted to establish if the use of debt was positively or negatively related to the size, age and profitability of the firm. To achieve these objectives, the study hypothesised that age, size and profitability amongst other factors were determinants of capital structure. The study further hypothesised that the use of retained profits by SMEs was negatively related with age, size and profitability of the firm. Furthermore the study hypothesised that the use of external equity by SMEs was negatively related with age, size and profitability of the firm. Finally, the study hypothesised that the use of debt by SMEs was negatively related to the size, age and profitability of the firm. The results revealed that size, age and profitability of the firm were some of the major determinants of capital structure. Finally, the study recommended that SMEs, commercial banks and the South African government take measures to improve access to capital by SMEs. Such measures included government intervention in reducing discrimination from the banks as well as encouragement of SMEs training and education so that they are empowered with business and financial management skills.
- Full Text:
- Date Issued: 2009
- Authors: Rungani, Ellen Chenesai
- Date: 2009
- Subjects: Debt-to-equity ratio , Capital , Value , Business enterprises -- South Africa -- Eastern Cape , Small business -- South Africa -- Eastern Cape , Municipal government -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , M Com (Business Management)
- Identifier: vital:11317 , http://hdl.handle.net/10353/271 , Debt-to-equity ratio , Capital , Value , Business enterprises -- South Africa -- Eastern Cape , Small business -- South Africa -- Eastern Cape , Municipal government -- South Africa -- Eastern Cape
- Description: This study investigated the determinants of capital structure of small and medium enterprises (SMEs) in the Buffalo city municipality in the Eastern Cape Province of South Africa. The objectives of the study were, to ascertain whether the use of internal equity (retained profits) was positively or negatively related to the size, age and profitability of the firm. Furthermore the study examined if the use of external equity (capital from owners) was negatively or positively related to the age, size and profitability of the firm. Finally the study wanted to establish if the use of debt was positively or negatively related to the size, age and profitability of the firm. To achieve these objectives, the study hypothesised that age, size and profitability amongst other factors were determinants of capital structure. The study further hypothesised that the use of retained profits by SMEs was negatively related with age, size and profitability of the firm. Furthermore the study hypothesised that the use of external equity by SMEs was negatively related with age, size and profitability of the firm. Finally, the study hypothesised that the use of debt by SMEs was negatively related to the size, age and profitability of the firm. The results revealed that size, age and profitability of the firm were some of the major determinants of capital structure. Finally, the study recommended that SMEs, commercial banks and the South African government take measures to improve access to capital by SMEs. Such measures included government intervention in reducing discrimination from the banks as well as encouragement of SMEs training and education so that they are empowered with business and financial management skills.
- Full Text:
- Date Issued: 2009
Determinants of grade 9 learners' intention to select science/applied sciences as curriculum stream for grade 10: an exploratory study of selected secondary schools in Amathole district
- Authors: Komle, Lindumzi Johnson
- Date: 2009
- Subjects: Curriculum planning -- South Africa -- Eastern Cape , Science -- Study and teaching -- South Africa -- Eastern Cape , Technology -- Study and teaching -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , M Ed
- Identifier: vital:16157 , http://hdl.handle.net/10353/223 , Curriculum planning -- South Africa -- Eastern Cape , Science -- Study and teaching -- South Africa -- Eastern Cape , Technology -- Study and teaching -- South Africa -- Eastern Cape
- Description: In schools in the Amathole District and throughout the rest of South Africa efforts are being made to encourage learners to pursue the Science and Applied Science curriculum stream in Grades 10 to 12. The aim of this study was both to determine and to explore those factors which, according to grade 9 learners, would either attract them to or deter them from following the Science and Applied Science curriculum stream from Grade 10 onwards. The study also sought to ascertain the views of teachers regarding the issues raised by the learners. A sample comprising 346 learners and 3 teachers were involved in the study. Using both quantitative and qualitative methods within the context of a post-positivist paradigm and utilising questionnaires and interviews, the study found that, consistent with existing research, there are both intrinsic and extrinsic related factors which play a role in the intention of learners to consider pursuing the Science and Applied Science curriculum stream. The intrinsic factors include learners‟ enjoyment of practical work and love for the Science and Applied Science. Extrinsic factors include perception that jobs in the field of Science and Applied Science compensate well. However, it was the intrinsic factors that pushed the learners to have the intention to follow the Science and Applied Science curriculum stream. Sociological, economic and personal dynamics seem to account for these patterns in the results. By contrast, two key sets of factors deterred the learners from the Science and Applied Science curriculum stream. One relates to factors in their internal loci of control, and the other to factors in learners‟ external loci of control. The internal locus of control factors had a greater influence, which suggests, according to attribution theorists, that the learners were inclined to look within themselves for the reasons that deterred them from the Science and Applied Science curriculum stream. In addition, a cluster analysis was conducted to ascertain whether the demographic profiles of the learners played a role in respect of their intention to pursue the Science and Applied Science curriculum stream. This cluster analysis revealed that, in terms of gender, males were more inclined than females to follow the Science and Applied Science stream. However, it was also significant that peer influence played an important role in attracting males to the Science and Applied Science curriculum stream, whereas it was career interest factors that attracted the females. In terms of ethnic groups, Indians and blacks were more inclined than coloureds and whites to follow the Science and Applied Science stream with whites being the least attracted to this stream. Career choice dynamics provide some explanations for these outcomes. The key contribution of this study lies in the fact that the study has shown that practical work as a teaching strategy may result in greater learner participation in the Science and Applied Science curriculum stream. The study recommends that, in order to promote greater participation in the Science and Applied Science curriculum stream in schools, strategies related to teaching in terms of which both genders are taken into consideration should be implemented. Other recommendations were also made. Nevertheless, it must be borne in mind that the study is a case study and that it is, therefore, not possible to generalise the findings.
- Full Text:
- Date Issued: 2009
- Authors: Komle, Lindumzi Johnson
- Date: 2009
- Subjects: Curriculum planning -- South Africa -- Eastern Cape , Science -- Study and teaching -- South Africa -- Eastern Cape , Technology -- Study and teaching -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , M Ed
- Identifier: vital:16157 , http://hdl.handle.net/10353/223 , Curriculum planning -- South Africa -- Eastern Cape , Science -- Study and teaching -- South Africa -- Eastern Cape , Technology -- Study and teaching -- South Africa -- Eastern Cape
- Description: In schools in the Amathole District and throughout the rest of South Africa efforts are being made to encourage learners to pursue the Science and Applied Science curriculum stream in Grades 10 to 12. The aim of this study was both to determine and to explore those factors which, according to grade 9 learners, would either attract them to or deter them from following the Science and Applied Science curriculum stream from Grade 10 onwards. The study also sought to ascertain the views of teachers regarding the issues raised by the learners. A sample comprising 346 learners and 3 teachers were involved in the study. Using both quantitative and qualitative methods within the context of a post-positivist paradigm and utilising questionnaires and interviews, the study found that, consistent with existing research, there are both intrinsic and extrinsic related factors which play a role in the intention of learners to consider pursuing the Science and Applied Science curriculum stream. The intrinsic factors include learners‟ enjoyment of practical work and love for the Science and Applied Science. Extrinsic factors include perception that jobs in the field of Science and Applied Science compensate well. However, it was the intrinsic factors that pushed the learners to have the intention to follow the Science and Applied Science curriculum stream. Sociological, economic and personal dynamics seem to account for these patterns in the results. By contrast, two key sets of factors deterred the learners from the Science and Applied Science curriculum stream. One relates to factors in their internal loci of control, and the other to factors in learners‟ external loci of control. The internal locus of control factors had a greater influence, which suggests, according to attribution theorists, that the learners were inclined to look within themselves for the reasons that deterred them from the Science and Applied Science curriculum stream. In addition, a cluster analysis was conducted to ascertain whether the demographic profiles of the learners played a role in respect of their intention to pursue the Science and Applied Science curriculum stream. This cluster analysis revealed that, in terms of gender, males were more inclined than females to follow the Science and Applied Science stream. However, it was also significant that peer influence played an important role in attracting males to the Science and Applied Science curriculum stream, whereas it was career interest factors that attracted the females. In terms of ethnic groups, Indians and blacks were more inclined than coloureds and whites to follow the Science and Applied Science stream with whites being the least attracted to this stream. Career choice dynamics provide some explanations for these outcomes. The key contribution of this study lies in the fact that the study has shown that practical work as a teaching strategy may result in greater learner participation in the Science and Applied Science curriculum stream. The study recommends that, in order to promote greater participation in the Science and Applied Science curriculum stream in schools, strategies related to teaching in terms of which both genders are taken into consideration should be implemented. Other recommendations were also made. Nevertheless, it must be borne in mind that the study is a case study and that it is, therefore, not possible to generalise the findings.
- Full Text:
- Date Issued: 2009
Determination and validation of plants used by resource-limited farmers in the ethno veterinary control of gastro-intestinal parasites of goats in the Eastern Cape Province, South Africa
- Authors: Maphosa, Viola
- Date: 2009
- Subjects: Medicinal plants -- South Africa -- Eastern Cape , Parasites -- Control -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Goats -- Parasites -- Control , Traditional veterinary medicine -- South Africa , Sustainable agriculture -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Animal Science)
- Identifier: vital:11164 , http://hdl.handle.net/10353/d1000997 , Medicinal plants -- South Africa -- Eastern Cape , Parasites -- Control -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Goats -- Parasites -- Control , Traditional veterinary medicine -- South Africa , Sustainable agriculture -- South Africa -- Eastern Cape
- Full Text:
- Date Issued: 2009
- Authors: Maphosa, Viola
- Date: 2009
- Subjects: Medicinal plants -- South Africa -- Eastern Cape , Parasites -- Control -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Goats -- Parasites -- Control , Traditional veterinary medicine -- South Africa , Sustainable agriculture -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD (Animal Science)
- Identifier: vital:11164 , http://hdl.handle.net/10353/d1000997 , Medicinal plants -- South Africa -- Eastern Cape , Parasites -- Control -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Goats -- Parasites -- Control , Traditional veterinary medicine -- South Africa , Sustainable agriculture -- South Africa -- Eastern Cape
- Full Text:
- Date Issued: 2009
Determinism and reactive attitudes: reflections on our alleged unrenounceable commitments
- Authors: Kelland, Lindsay-Ann
- Date: 2009
- Subjects: Free will and determinism Responsibility
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2713 , http://hdl.handle.net/10962/d1002843
- Description: There seems to exist a tension between our metaphysical and phenomenological commitments in the free will debate. On the one hand, I argue that at the metaphysical level we cannot coherently defend the belief that we are morally responsible in the sense that we deserve to be rewarded and punished for our actions, where desert-entailing moral responsibility is the primary understanding of moral responsibility presupposed in the free will debate. I argue that we are responsible for our actions but only in the weaker sense, termed ‘attributability’ by Gary Watson. On the other hand, we are allegedly unrenounceably committed at the phenomenological level to conceiving of, and treating, ourselves and one another as morally responsible beings in the desert-entailing sense. P. F. Strawson famously defends this claim in his seminal work, ‘Freedom and Resentment’. In my thesis I will set out this tension by exploring both commitments in turn. I then aim to show that the tension can be dissolved by arguing, contra P. F. Strawson, that our phenomenological commitment is not in fact unrenounceable. The dissolution of this tension entails, I argue, that we must examine our conception of self and other. We must explore the implications of adopting a position which denies that we are morally responsible beings for our life-hopes, personal feelings, inter-personal relationships and projects. Most importantly, I argue that we must renounce our current retributive condemnatory practices which are based on the unjustified belief that we are morally responsible beings.
- Full Text:
- Date Issued: 2009
- Authors: Kelland, Lindsay-Ann
- Date: 2009
- Subjects: Free will and determinism Responsibility
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2713 , http://hdl.handle.net/10962/d1002843
- Description: There seems to exist a tension between our metaphysical and phenomenological commitments in the free will debate. On the one hand, I argue that at the metaphysical level we cannot coherently defend the belief that we are morally responsible in the sense that we deserve to be rewarded and punished for our actions, where desert-entailing moral responsibility is the primary understanding of moral responsibility presupposed in the free will debate. I argue that we are responsible for our actions but only in the weaker sense, termed ‘attributability’ by Gary Watson. On the other hand, we are allegedly unrenounceably committed at the phenomenological level to conceiving of, and treating, ourselves and one another as morally responsible beings in the desert-entailing sense. P. F. Strawson famously defends this claim in his seminal work, ‘Freedom and Resentment’. In my thesis I will set out this tension by exploring both commitments in turn. I then aim to show that the tension can be dissolved by arguing, contra P. F. Strawson, that our phenomenological commitment is not in fact unrenounceable. The dissolution of this tension entails, I argue, that we must examine our conception of self and other. We must explore the implications of adopting a position which denies that we are morally responsible beings for our life-hopes, personal feelings, inter-personal relationships and projects. Most importantly, I argue that we must renounce our current retributive condemnatory practices which are based on the unjustified belief that we are morally responsible beings.
- Full Text:
- Date Issued: 2009
Developing an ionospheric map for South Africa
- Authors: Okoh, Daniel Izuikeninachi
- Date: 2009
- Subjects: Ionosphere -- South Africa , Shortwave radio , Ionospheric electron density -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5459 , http://hdl.handle.net/10962/d1005244 , Ionosphere -- South Africa , Shortwave radio , Ionospheric electron density -- South Africa
- Description: This thesis describes the development of an ionospheric map for the South African region using the current available resources. The International Reference Ionosphere (IRI) model, the South African Bottomside Ionospheric Model (SABIM), and measurements from ionosondes in the South African Ionosonde Network, were incorporated into the map. An accurate ionospheric map depicting the foF2 and hmF2 parameters as well as electron density profiles at any location within South Africa is a useful tool for, amongst others, High Frequency (HF) communicators and space weather centers. A major product of the work is software, written in MATLAB, which produces spatial and temporal representations of the South African ionosphere. The map was validated and demonstrated for practical application, since a significant aim of the project was to make the map as applicable as possible. It is hoped that the map will find immense application in HF radio communication industries, research industries, aviation industries, and other industries that make use of Earth-Space systems. A potential user of the map is GrinTek Ewation (GEW) who is currently evaluating it for their purposes
- Full Text:
- Date Issued: 2009
- Authors: Okoh, Daniel Izuikeninachi
- Date: 2009
- Subjects: Ionosphere -- South Africa , Shortwave radio , Ionospheric electron density -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5459 , http://hdl.handle.net/10962/d1005244 , Ionosphere -- South Africa , Shortwave radio , Ionospheric electron density -- South Africa
- Description: This thesis describes the development of an ionospheric map for the South African region using the current available resources. The International Reference Ionosphere (IRI) model, the South African Bottomside Ionospheric Model (SABIM), and measurements from ionosondes in the South African Ionosonde Network, were incorporated into the map. An accurate ionospheric map depicting the foF2 and hmF2 parameters as well as electron density profiles at any location within South Africa is a useful tool for, amongst others, High Frequency (HF) communicators and space weather centers. A major product of the work is software, written in MATLAB, which produces spatial and temporal representations of the South African ionosphere. The map was validated and demonstrated for practical application, since a significant aim of the project was to make the map as applicable as possible. It is hoped that the map will find immense application in HF radio communication industries, research industries, aviation industries, and other industries that make use of Earth-Space systems. A potential user of the map is GrinTek Ewation (GEW) who is currently evaluating it for their purposes
- Full Text:
- Date Issued: 2009
Development and validation of a stability-indicating method for the quantitation of paclitaxel in pharmaceutical dosage forms
- Mohammadi, Ali, Esimaeili, Farnaz, Dinarvand, Rasoul, Atyabi, Fatemeh, Walker, Roderick B
- Authors: Mohammadi, Ali , Esimaeili, Farnaz , Dinarvand, Rasoul , Atyabi, Fatemeh , Walker, Roderick B
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184278 , vital:44196 , xlink:href="https://doi.org/10.1093/chromsci/47.7.599"
- Description: A simple, rapid stability-indicating isocratic assay has been developed and validated for the determination of Paclitaxel (PTX) in commercial injection formulations. The assay is performed using a Nucleosil RP-18 (5 µm, 250 × 4.0 mm i.d) column protected by a Nucleosil C18 precolumn (5 µm, 4.0 × 4.0 mm i.d.) with a mobile phase of methanol–water (80:20) and UV detection at 230 nm. The method was found to be specific for PTX in the presence of degradation products with an overall analytical run time of ~ 9 min. Accuracy reported as % bias was found to be 0.1–2.5% bias for all samples tested. Intra-assay precision (repeatability) was found to be 0.22–2.65% RSD, while inter-day precision (intermediate precision) was found to be 1.0–3.0% RSD for the samples studied. The calibration curve was found to be linear with the equation y = 29.78x + 7.65, and a linear regression coefficient of 0.9994 over the concentration range 0.05–20 µg/mL. The limits of quantitation and detection were 0.05 and 0.02 µg/mL, respectively. Taxol (30 mg/5 mL), a commercially available dosage form of PTX, was assayed and 100.6–103.6% of the label claim was recovered.
- Full Text:
- Date Issued: 2009
- Authors: Mohammadi, Ali , Esimaeili, Farnaz , Dinarvand, Rasoul , Atyabi, Fatemeh , Walker, Roderick B
- Date: 2009
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/184278 , vital:44196 , xlink:href="https://doi.org/10.1093/chromsci/47.7.599"
- Description: A simple, rapid stability-indicating isocratic assay has been developed and validated for the determination of Paclitaxel (PTX) in commercial injection formulations. The assay is performed using a Nucleosil RP-18 (5 µm, 250 × 4.0 mm i.d) column protected by a Nucleosil C18 precolumn (5 µm, 4.0 × 4.0 mm i.d.) with a mobile phase of methanol–water (80:20) and UV detection at 230 nm. The method was found to be specific for PTX in the presence of degradation products with an overall analytical run time of ~ 9 min. Accuracy reported as % bias was found to be 0.1–2.5% bias for all samples tested. Intra-assay precision (repeatability) was found to be 0.22–2.65% RSD, while inter-day precision (intermediate precision) was found to be 1.0–3.0% RSD for the samples studied. The calibration curve was found to be linear with the equation y = 29.78x + 7.65, and a linear regression coefficient of 0.9994 over the concentration range 0.05–20 µg/mL. The limits of quantitation and detection were 0.05 and 0.02 µg/mL, respectively. Taxol (30 mg/5 mL), a commercially available dosage form of PTX, was assayed and 100.6–103.6% of the label claim was recovered.
- Full Text:
- Date Issued: 2009
Development of a neural network based model for predicting the occurrence of spread F within the Brazilian sector
- Authors: Paradza, Masimba Wellington
- Date: 2009
- Subjects: Neural networks (Computer science) , Ionosphere , F region
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5460 , http://hdl.handle.net/10962/d1005245 , Neural networks (Computer science) , Ionosphere , F region
- Description: Spread F is a phenomenon of the ionosphere in which the pulses returned from the ionosphere are of a much greater duration than the transmitted ones. The occurrence of spread F can be predicted using the technique of Neural Networks (NNs). This thesis presents the development and evaluation of NN based models (two single station models and a regional model) for predicting the occurrence of spread F over selected stations within the Brazilian sector. The input space for the NNs included the day number (seasonal variation), hour (diurnal variation), sunspot number (measure of the solar activity), magnetic index (measure of the magnetic activity) and magnetic position (latitude, magnetic declination and inclination). Twelve years of spread F data measured during 1978 to 1989 inclusively at the equatorial site Fortaleza and low latitude site Cachoeira Paulista are used in the development of an input space and NN architecture for the NN models. Spread F data that is believed to be related to plasma bubble developments (range spread F) were used in the development of the models while those associated with narrow spectrum irregularities that occur near the F layer (frequency spread F) were excluded. The results of the models show the dependency of the probability of spread F as a function of local time, season and latitude. The models also illustrate some characteristics of spread F such as the onset and peak occurrence of spread F as a function of distance from the equator. Results from these models are presented in this thesis and compared to measured data and to modelled data obtained with an empirical model developed for the same purpose.
- Full Text:
- Date Issued: 2009
- Authors: Paradza, Masimba Wellington
- Date: 2009
- Subjects: Neural networks (Computer science) , Ionosphere , F region
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5460 , http://hdl.handle.net/10962/d1005245 , Neural networks (Computer science) , Ionosphere , F region
- Description: Spread F is a phenomenon of the ionosphere in which the pulses returned from the ionosphere are of a much greater duration than the transmitted ones. The occurrence of spread F can be predicted using the technique of Neural Networks (NNs). This thesis presents the development and evaluation of NN based models (two single station models and a regional model) for predicting the occurrence of spread F over selected stations within the Brazilian sector. The input space for the NNs included the day number (seasonal variation), hour (diurnal variation), sunspot number (measure of the solar activity), magnetic index (measure of the magnetic activity) and magnetic position (latitude, magnetic declination and inclination). Twelve years of spread F data measured during 1978 to 1989 inclusively at the equatorial site Fortaleza and low latitude site Cachoeira Paulista are used in the development of an input space and NN architecture for the NN models. Spread F data that is believed to be related to plasma bubble developments (range spread F) were used in the development of the models while those associated with narrow spectrum irregularities that occur near the F layer (frequency spread F) were excluded. The results of the models show the dependency of the probability of spread F as a function of local time, season and latitude. The models also illustrate some characteristics of spread F such as the onset and peak occurrence of spread F as a function of distance from the equator. Results from these models are presented in this thesis and compared to measured data and to modelled data obtained with an empirical model developed for the same purpose.
- Full Text:
- Date Issued: 2009
Development of a performance management system for the SABC (Port Elizabeth)
- Authors: Nyembezi, Vuyo
- Date: 2009
- Subjects: Performance standards -- South Africa -- Port Elizabeth , Performance -- Management -- Evaluation , Performance -- Measurement , Employees -- Rating of -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8678 , http://hdl.handle.net/10948/1148 , Performance standards -- South Africa -- Port Elizabeth , Performance -- Management -- Evaluation , Performance -- Measurement , Employees -- Rating of -- South Africa -- Port Elizabeth
- Description: This study focused on exploring and finding the ideal performance management system suitable for the South African Broadcasting Corporation by establishing an understanding of employees’ experiences and perceptions of the previous and a proposed performance management systems and their value to SABC employees. This was done by eliciting how employees see, make sense of and interpret their everyday experiences of performance management systems, in order to develop a more suitable inclusive performance management system. A qualitative study was used to seek answers to the research questions. A focus group interview was selected for data collection. The data was analysed according to guidelines indicated and proposed by Creswell (1998:147-148). The researcher made use of convenience sampling to select 45 participants in 5 groups for the focus groups. One group consisted of managers/supervisors, and the other four groups were employees from four different business units. Participants were guaranteed confidentiality. Credibility, transferability, dependability and conformability were used as the main components in the model, to determine the truth-value of the study. Findings indicated that there was a fair understanding of the previous performance management system but there had been poor implementation of the system. The participants concurred that the previous performance iv management systems in the organisations were not adding any value to their lives. They pointed out that there was no reward in place for high performers and no action taken for non-performers, and this impacted negatively on how implementation was perceived and experienced. The recommendations are that the revised performance management system should have a stronger emphasis on effective management, monitoring, feedback and reward. Furthermore, the system should close the current gaps of reward for high performance and correction of low performance. It was further concluded that for a performance management system to be effective, it should incorporate updated job descriptions, performance measures and standards, as well as evaluator training and guidelines for improvement, employee input, compensation and/or rewards.
- Full Text:
- Date Issued: 2009
- Authors: Nyembezi, Vuyo
- Date: 2009
- Subjects: Performance standards -- South Africa -- Port Elizabeth , Performance -- Management -- Evaluation , Performance -- Measurement , Employees -- Rating of -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8678 , http://hdl.handle.net/10948/1148 , Performance standards -- South Africa -- Port Elizabeth , Performance -- Management -- Evaluation , Performance -- Measurement , Employees -- Rating of -- South Africa -- Port Elizabeth
- Description: This study focused on exploring and finding the ideal performance management system suitable for the South African Broadcasting Corporation by establishing an understanding of employees’ experiences and perceptions of the previous and a proposed performance management systems and their value to SABC employees. This was done by eliciting how employees see, make sense of and interpret their everyday experiences of performance management systems, in order to develop a more suitable inclusive performance management system. A qualitative study was used to seek answers to the research questions. A focus group interview was selected for data collection. The data was analysed according to guidelines indicated and proposed by Creswell (1998:147-148). The researcher made use of convenience sampling to select 45 participants in 5 groups for the focus groups. One group consisted of managers/supervisors, and the other four groups were employees from four different business units. Participants were guaranteed confidentiality. Credibility, transferability, dependability and conformability were used as the main components in the model, to determine the truth-value of the study. Findings indicated that there was a fair understanding of the previous performance management system but there had been poor implementation of the system. The participants concurred that the previous performance iv management systems in the organisations were not adding any value to their lives. They pointed out that there was no reward in place for high performers and no action taken for non-performers, and this impacted negatively on how implementation was perceived and experienced. The recommendations are that the revised performance management system should have a stronger emphasis on effective management, monitoring, feedback and reward. Furthermore, the system should close the current gaps of reward for high performance and correction of low performance. It was further concluded that for a performance management system to be effective, it should incorporate updated job descriptions, performance measures and standards, as well as evaluator training and guidelines for improvement, employee input, compensation and/or rewards.
- Full Text:
- Date Issued: 2009
Development of a process for the preparation of linalool from CIS-2-pinanol
- Authors: Buddoo, Subash Ramnarain
- Date: 2009
- Subjects: Odors , Perfumes -- History , Perfumes -- Formulae , Fermentation
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10425 , http://hdl.handle.net/10948/d1016219
- Description: Linalool is a key intermediate for the production of important fragrance chemicals such as geraniol, nerol, geranial, and neral. Linalool can be produced via a two-step process from α-pinene which is a major component of crude sulphated turpentine (CST) a foul-smelling, volatile waste product of the pulp and paper industry. The key step in this process is the pyrolysis step which involves the isomerisation of cis-2-pinanol to linalool and requires high temperatures (600-650°C) and is not very selective due to the decomposition of the product itself under these conditions. A client of the CSIR, Teubes Pty. Ltd., is a manufacturer of flavour and fragrance compounds for the local and international fragrance market and expressed an interest in producing linalool since the company would then gain access to other valuable fragrance chemicals via relatively simple processes. Earlier work conducted by AECI, R & D did not meet with much success since the selectivity to linalool was very poor and the process could hardly be deemed as scalable. The main objective of this project was therefore to develop a process for the selective isomerisation of cis-2-pinanol to linalool with minimum by-product formation and using process equipment that could be scaled to full-scale production. Since cis-2- pinanol could not be purchased in sufficient quantities for process development, a process had to be developed for the bench-scale preparation of kilogram quantities of cis-2-pinanol from α-pinene obtained from the client. Although this synthesis formed a minor part of this investigation, several process improvements and innovations were introduced to produce high quality cis-2-pinanol, in very good yields at kilogram scale. A major part of this investigation was the design and set up of a pyrolyis rig capable of operating at elevated temperatures (400 - 750°C) for the evaluation of various process parameters. Various vaporizer, reactor, and condensation systems were evaluated for their ability to cope with the demanding conditions on a consistent basis. The initial part of the investigation was a screening exercise to evaluate various process parameters as well as solvents, materials of construction, catalysts, etc. A comprehensive statistical design was also conducted to determine the critical process parameters and the model obtained was used to predict the optimum conditions required for the preparation of in-specification product on a consistent basis. These conditions were used in the preparation of a 1kg sample which was required by theclient for market evaluation purposes. The use of a novel microreactor system was also evaluated for the pinanol pyrolysis reaction. To our knowledge, this is the first time that a microreactor has been successfully used for this type of reaction in the Fragrance industry and a patent application is being filed by the CSIR. The kinetics of the reaction in both the tubular reactor system and the microreactor system was investigated. Computer modelling studies on both the systems were also conducted. The raw material cost to produce a kilogram of linalool is $1.40. There is a significant margin of 60.8 percent between the raw material cost of linalool and the current selling price ($3.57/kg). This clearly indicates that the project is potentially feasible from an economic point of view and we can now proceed with confidence to the next stage which is the engineering design, building and commissioning of the large scale pyrolysis rig. The rest of the process steps will be conducted on existing equipment currently present at the CSIR’s large scale facility (Imbiza in Isando, Gauteng).
- Full Text:
- Date Issued: 2009
- Authors: Buddoo, Subash Ramnarain
- Date: 2009
- Subjects: Odors , Perfumes -- History , Perfumes -- Formulae , Fermentation
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:10425 , http://hdl.handle.net/10948/d1016219
- Description: Linalool is a key intermediate for the production of important fragrance chemicals such as geraniol, nerol, geranial, and neral. Linalool can be produced via a two-step process from α-pinene which is a major component of crude sulphated turpentine (CST) a foul-smelling, volatile waste product of the pulp and paper industry. The key step in this process is the pyrolysis step which involves the isomerisation of cis-2-pinanol to linalool and requires high temperatures (600-650°C) and is not very selective due to the decomposition of the product itself under these conditions. A client of the CSIR, Teubes Pty. Ltd., is a manufacturer of flavour and fragrance compounds for the local and international fragrance market and expressed an interest in producing linalool since the company would then gain access to other valuable fragrance chemicals via relatively simple processes. Earlier work conducted by AECI, R & D did not meet with much success since the selectivity to linalool was very poor and the process could hardly be deemed as scalable. The main objective of this project was therefore to develop a process for the selective isomerisation of cis-2-pinanol to linalool with minimum by-product formation and using process equipment that could be scaled to full-scale production. Since cis-2- pinanol could not be purchased in sufficient quantities for process development, a process had to be developed for the bench-scale preparation of kilogram quantities of cis-2-pinanol from α-pinene obtained from the client. Although this synthesis formed a minor part of this investigation, several process improvements and innovations were introduced to produce high quality cis-2-pinanol, in very good yields at kilogram scale. A major part of this investigation was the design and set up of a pyrolyis rig capable of operating at elevated temperatures (400 - 750°C) for the evaluation of various process parameters. Various vaporizer, reactor, and condensation systems were evaluated for their ability to cope with the demanding conditions on a consistent basis. The initial part of the investigation was a screening exercise to evaluate various process parameters as well as solvents, materials of construction, catalysts, etc. A comprehensive statistical design was also conducted to determine the critical process parameters and the model obtained was used to predict the optimum conditions required for the preparation of in-specification product on a consistent basis. These conditions were used in the preparation of a 1kg sample which was required by theclient for market evaluation purposes. The use of a novel microreactor system was also evaluated for the pinanol pyrolysis reaction. To our knowledge, this is the first time that a microreactor has been successfully used for this type of reaction in the Fragrance industry and a patent application is being filed by the CSIR. The kinetics of the reaction in both the tubular reactor system and the microreactor system was investigated. Computer modelling studies on both the systems were also conducted. The raw material cost to produce a kilogram of linalool is $1.40. There is a significant margin of 60.8 percent between the raw material cost of linalool and the current selling price ($3.57/kg). This clearly indicates that the project is potentially feasible from an economic point of view and we can now proceed with confidence to the next stage which is the engineering design, building and commissioning of the large scale pyrolysis rig. The rest of the process steps will be conducted on existing equipment currently present at the CSIR’s large scale facility (Imbiza in Isando, Gauteng).
- Full Text:
- Date Issued: 2009
Development of biological control strategies against sirex noctilio (Fabricius) on Sappi Forests (Ltd) Landholdings in the summer rainfall regions of South Africa
- Authors: Verleur, Peter Marcel
- Date: 2009
- Subjects: Pests -- Biological control -- South Africa , Nonindigenous pests -- Control
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10741 , http://hdl.handle.net/10948/1273 , Pests -- Biological control -- South Africa , Nonindigenous pests -- Control
- Description: The commercial forest industry in South Africa is predominantly dependent on large tracts of exotic monoculture plantations. While this simplifies management practice, there is always the inherent danger posed by introduced pests and diseases. Classical biological control is usually the most effective control method against introduced exotic pests. Climatic factors and seasonal differences may negatively affect the ability of the natural enemies to establish successfully at the new location. Successful establishment of the natural enemies usually results in control over the pest within four years. Sirex noctilio naturally occurs in the mediterranean countries of Europe and North Africa. It is the only member of the Siricid family capable of killing living pine trees. Sirex noctilio was accidentally introduced into New Zealand from Europe during the early 1900s. It has since been found in Australia, Brazil, Argentina South Africa and Chile. Initial biological control in New Zealand and Tasmania was through the release of Siricid specific parasitoid wasps from Europe and North America. The discovery of the accidental introduction of the entomophagous nematode Beddingia siricidicola and its subsequent artificial culturing for release provided the platform for the biological control methodology, which brought the Sirex woodwasp under control. The methods and natural enemies used in New Zealand and Australia were introduced by the South American countries and in the Western Cape of South Africa. Successful biological control was achieved in the Western Cape within two years after the initial introduction of the nematode B. siricidicola. The migration of S. noctilio into the summer rainfall regions of South Africa occurred in the absence of the associated natural enemies. This resulted in rapid population growth of the pest and substantial damage was caused to plantations of Pinus patula in the Eastern Cape and KwaZulu-Natal. Initial attempts at introducing B. siricidicola during 2004 were not very successful. This study contributes to the understanding and adaptation of the biological control methods to the summer rainfall climate. The key finding was that in the summer rainfall climate, only the bottom third of nematode inoculated S. noctilio infested trees produced parasitized adults during the emergence period. A comparative study was done on log samples from S. noctilio infested trees collected in the Western Cape and KwaZulu-Natal. iv An adapted nematode inoculation technique for pulpwood plantations in the summer rainfall regions was developed and implemented in mass inoculations with B. siricidicola during 2007 and 2008. Locally available herbicides were tested for suitability of use in the establishment of trap trees, which would attract ovipositing S. noctilio females in situations where low numbers of the woodwasp occur. Determination of the levels of natural B. siricidicola parasitism in S. noctilio adults during the 2008 emergence period indicate successful establishment of the nematode in KwaZulu-Natal. Successful introduction of the parasitoid wasp Ibalia leucospoides into the summer rainfall regions has also been achieved.
- Full Text:
- Date Issued: 2009
- Authors: Verleur, Peter Marcel
- Date: 2009
- Subjects: Pests -- Biological control -- South Africa , Nonindigenous pests -- Control
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10741 , http://hdl.handle.net/10948/1273 , Pests -- Biological control -- South Africa , Nonindigenous pests -- Control
- Description: The commercial forest industry in South Africa is predominantly dependent on large tracts of exotic monoculture plantations. While this simplifies management practice, there is always the inherent danger posed by introduced pests and diseases. Classical biological control is usually the most effective control method against introduced exotic pests. Climatic factors and seasonal differences may negatively affect the ability of the natural enemies to establish successfully at the new location. Successful establishment of the natural enemies usually results in control over the pest within four years. Sirex noctilio naturally occurs in the mediterranean countries of Europe and North Africa. It is the only member of the Siricid family capable of killing living pine trees. Sirex noctilio was accidentally introduced into New Zealand from Europe during the early 1900s. It has since been found in Australia, Brazil, Argentina South Africa and Chile. Initial biological control in New Zealand and Tasmania was through the release of Siricid specific parasitoid wasps from Europe and North America. The discovery of the accidental introduction of the entomophagous nematode Beddingia siricidicola and its subsequent artificial culturing for release provided the platform for the biological control methodology, which brought the Sirex woodwasp under control. The methods and natural enemies used in New Zealand and Australia were introduced by the South American countries and in the Western Cape of South Africa. Successful biological control was achieved in the Western Cape within two years after the initial introduction of the nematode B. siricidicola. The migration of S. noctilio into the summer rainfall regions of South Africa occurred in the absence of the associated natural enemies. This resulted in rapid population growth of the pest and substantial damage was caused to plantations of Pinus patula in the Eastern Cape and KwaZulu-Natal. Initial attempts at introducing B. siricidicola during 2004 were not very successful. This study contributes to the understanding and adaptation of the biological control methods to the summer rainfall climate. The key finding was that in the summer rainfall climate, only the bottom third of nematode inoculated S. noctilio infested trees produced parasitized adults during the emergence period. A comparative study was done on log samples from S. noctilio infested trees collected in the Western Cape and KwaZulu-Natal. iv An adapted nematode inoculation technique for pulpwood plantations in the summer rainfall regions was developed and implemented in mass inoculations with B. siricidicola during 2007 and 2008. Locally available herbicides were tested for suitability of use in the establishment of trap trees, which would attract ovipositing S. noctilio females in situations where low numbers of the woodwasp occur. Determination of the levels of natural B. siricidicola parasitism in S. noctilio adults during the 2008 emergence period indicate successful establishment of the nematode in KwaZulu-Natal. Successful introduction of the parasitoid wasp Ibalia leucospoides into the summer rainfall regions has also been achieved.
- Full Text:
- Date Issued: 2009
Development of flexible automotive measurement adaptors for the PQ25 VWSA platform
- Authors: Pretorius, Shaun
- Date: 2009
- Subjects: Automobiles -- Measurement , Optical measurements
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9626 , http://hdl.handle.net/10948/1632 , http://hdl.handle.net/10948/d1011725 , Automobiles -- Measurement , Optical measurements
- Description: The following work describes all knowledge required in the creation of new automotive optical Photogrammetrical adaptors, which allow the user thereof to measure a fully assembled vehicle in its natural position, i.e. on its wheels for the PQ25 platform at Volkswagen of South Africa. The system is the only method available to the manufacturing plant to measure a fully assembled vehicle in this manner. The FlexMess system allows for a quick portable measurement of a vehicle at all stages of Vehicle manufacturing, aligned via the Volkswagen RPS standards. In the first part of the work, the problem of establishing a system capable of measuring the PQ25 platform is achieved by redesigning the PQ24 platform (previous generation Polo) to the new PQ25 vehicle platform. Once the system was redesigned a prototype adaptor system was created. In the second part of the work, the redesigned adaptor system is checked for its accuracy and repeatability. In a statistical analysis of the adaptors ability to measure the reference points needed for alignment of a vehicle, the system is compared to a CMM and verified that the limits fall within the limits of the original FlexMesśs certified accuracy limits. The last part of the work looks at addressing some of the problems of the FlexMess system by creating concepts for an ideal future FlexMess adaptor system.
- Full Text:
- Date Issued: 2009
- Authors: Pretorius, Shaun
- Date: 2009
- Subjects: Automobiles -- Measurement , Optical measurements
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9626 , http://hdl.handle.net/10948/1632 , http://hdl.handle.net/10948/d1011725 , Automobiles -- Measurement , Optical measurements
- Description: The following work describes all knowledge required in the creation of new automotive optical Photogrammetrical adaptors, which allow the user thereof to measure a fully assembled vehicle in its natural position, i.e. on its wheels for the PQ25 platform at Volkswagen of South Africa. The system is the only method available to the manufacturing plant to measure a fully assembled vehicle in this manner. The FlexMess system allows for a quick portable measurement of a vehicle at all stages of Vehicle manufacturing, aligned via the Volkswagen RPS standards. In the first part of the work, the problem of establishing a system capable of measuring the PQ25 platform is achieved by redesigning the PQ24 platform (previous generation Polo) to the new PQ25 vehicle platform. Once the system was redesigned a prototype adaptor system was created. In the second part of the work, the redesigned adaptor system is checked for its accuracy and repeatability. In a statistical analysis of the adaptors ability to measure the reference points needed for alignment of a vehicle, the system is compared to a CMM and verified that the limits fall within the limits of the original FlexMesśs certified accuracy limits. The last part of the work looks at addressing some of the problems of the FlexMess system by creating concepts for an ideal future FlexMess adaptor system.
- Full Text:
- Date Issued: 2009