Eluvial chromite resources of the Great Dyke of Zimbabwe
- Authors: Musa, Caston Tamburayi
- Date: 2007
- Subjects: Dikes (Geology) -- Zimbabwe Chromite -- Zimbabwe Geology -- Zimbabwe Olivine Serpentinite Eluvium
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5046 , http://hdl.handle.net/10962/d1007731
- Description: Apart from the concentrations of chromite in layers within the Great Dyke and other ultramafic complexes, chromite also occurs as interstitial grains throughout the olivine-bearing rock-types. These olivine-bearing rocks include no rites, gabbros, dunites and pyroxenites. Chromite concentration in these rocks varies from 0.48 to 3.09 per cent of the rock, usually in the form of chromite (Ahrens, 1965; Worst, 1960). A small fraction of this chromite settled to form chromitite layers whilst the remainder is retained within the rock mass as finely disseminated chromite and chromite interstitial to olivine. This retained chromite is much finer grained than layer chromite and is the primary source of eluvial chromite (Cotterill, 1981). During weathering of the serpentine rock and transportation by rainwater, the heavier chromite and magnetite grains are re-deposited along watercourses and vleis or valleys as the speed of the water is retarded sufficiently for the heavier particles to settle. The lighter serpentine material is removed and the chromite concentration in the soil is increased, thus resulting in eluvial chromite (Keech et ai, 1961; Worst, 1960; Prendergast, 1978). The concentration of chromite particles in soil can be up to 15 (or more) Cr₂O₃ %, resulting in economic and exploitable deposits, located primarily along the Great Dyke fiacks. A preliminary evaluation of the eluvials indicate that the Great Dyke could be host to up to 10 million tonnes of potential chromite concentrates which could be processed from such eluvial concentrates. These chromite-rich soils can be mined more cheaply than the traditional seams mining and processed into chromite concentrates through simple mechanical processing techniques of spirals, jigs and heavy media separators. The resultant chromite concentrates are of high quality and can be used to manufacture chromite ore briquettes, which are an alternative to lumpy chromite smelter feed. The main challenges to eluvial mining are the inevitable environmental degradation and coming up with methods that could possibly mitigate against such environmental damage. The distribution of these eluvials over vast plains as thin soil horizons, necessitate use of mobile concentrator plants and hence establishment of extensive infrastructure. These challenges, however, are not insurmountable and test mining and previous production runs have proved profitable. The eluvials are also associated with some lateritic nickel concentrations. The nickel occurs in close association with some oxide such as goethite and garnierite and is associated with iron-manganiferous soil pisolites. The analyses of these pisolites indicate high nickel grades of generally above 1.00 %Ni. Such high nickel-content of Great Dyke laterites warrant, further investigations.
- Full Text:
- Date Issued: 2007
- Authors: Musa, Caston Tamburayi
- Date: 2007
- Subjects: Dikes (Geology) -- Zimbabwe Chromite -- Zimbabwe Geology -- Zimbabwe Olivine Serpentinite Eluvium
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5046 , http://hdl.handle.net/10962/d1007731
- Description: Apart from the concentrations of chromite in layers within the Great Dyke and other ultramafic complexes, chromite also occurs as interstitial grains throughout the olivine-bearing rock-types. These olivine-bearing rocks include no rites, gabbros, dunites and pyroxenites. Chromite concentration in these rocks varies from 0.48 to 3.09 per cent of the rock, usually in the form of chromite (Ahrens, 1965; Worst, 1960). A small fraction of this chromite settled to form chromitite layers whilst the remainder is retained within the rock mass as finely disseminated chromite and chromite interstitial to olivine. This retained chromite is much finer grained than layer chromite and is the primary source of eluvial chromite (Cotterill, 1981). During weathering of the serpentine rock and transportation by rainwater, the heavier chromite and magnetite grains are re-deposited along watercourses and vleis or valleys as the speed of the water is retarded sufficiently for the heavier particles to settle. The lighter serpentine material is removed and the chromite concentration in the soil is increased, thus resulting in eluvial chromite (Keech et ai, 1961; Worst, 1960; Prendergast, 1978). The concentration of chromite particles in soil can be up to 15 (or more) Cr₂O₃ %, resulting in economic and exploitable deposits, located primarily along the Great Dyke fiacks. A preliminary evaluation of the eluvials indicate that the Great Dyke could be host to up to 10 million tonnes of potential chromite concentrates which could be processed from such eluvial concentrates. These chromite-rich soils can be mined more cheaply than the traditional seams mining and processed into chromite concentrates through simple mechanical processing techniques of spirals, jigs and heavy media separators. The resultant chromite concentrates are of high quality and can be used to manufacture chromite ore briquettes, which are an alternative to lumpy chromite smelter feed. The main challenges to eluvial mining are the inevitable environmental degradation and coming up with methods that could possibly mitigate against such environmental damage. The distribution of these eluvials over vast plains as thin soil horizons, necessitate use of mobile concentrator plants and hence establishment of extensive infrastructure. These challenges, however, are not insurmountable and test mining and previous production runs have proved profitable. The eluvials are also associated with some lateritic nickel concentrations. The nickel occurs in close association with some oxide such as goethite and garnierite and is associated with iron-manganiferous soil pisolites. The analyses of these pisolites indicate high nickel grades of generally above 1.00 %Ni. Such high nickel-content of Great Dyke laterites warrant, further investigations.
- Full Text:
- Date Issued: 2007
Emotional intelligence and effective team functioning of MBA syndicate groups at the NMMU business school
- Authors: Doolabh, Chetna Gidhar
- Date: 2007
- Subjects: Emotional intelligence , Interpersonal relations , Teams in the workplace , Nelson Mandela Metropolitan University. Business School
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8747 , http://hdl.handle.net/10948/740 , Emotional intelligence , Interpersonal relations , Teams in the workplace , Nelson Mandela Metropolitan University. Business School
- Description: A common issue in leadership development is the high flyers who reach a position where their lack of “soft” skills hampers their performance and proves a barrier to their continued progression to higher levels of responsibility (Newell, 2002: 288). Business Schools offering Masters in Business Administration (MBA) programmes assist in developing managers with not just managerial competence but also with “soft” skills. By delivering educated business managers, these managers through their intellectual skills and community sensitive values, will lead future transformational processes. It is useful and interesting to consider how important emotional intelligence is for effective performance at work. A considerable body of research suggests that an employee’s ability to perceive, identify, and manage emotion provides the basis for the kinds of social and emotional competencies that are important for success in almost any position. Furthermore, as the pace of change increases and the world of work make ever-greater demands on an employee’s cognitive, emotional, and physical resources, this particular set of abilities will become increasingly important (Cherniss, 2000). The primary objective of this study is to determine the perceptions of the Masters in Business Administration (MBA), B-Tech in Business Administration (BBA), Advanced Business Programme (ABP) programmes and the Business School Alumni to determine the overall emotional intelligence profile of students as well as the effective team functions of the syndicate groups. Based on the main findings of the survey, it was concluded that emotional intelligence is an important factor for the NMMU Business School, MBA Unit students. The skills attained through the course work will not only improve team effectiveness in the syndicate group functioning but also enhance their performance in the business environment. The MBA team learning experiences enhances workplace learning as the ability to work in a team and ability to think and act independently are highly desired skills and competencies for success in the workplace.
- Full Text:
- Date Issued: 2007
- Authors: Doolabh, Chetna Gidhar
- Date: 2007
- Subjects: Emotional intelligence , Interpersonal relations , Teams in the workplace , Nelson Mandela Metropolitan University. Business School
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8747 , http://hdl.handle.net/10948/740 , Emotional intelligence , Interpersonal relations , Teams in the workplace , Nelson Mandela Metropolitan University. Business School
- Description: A common issue in leadership development is the high flyers who reach a position where their lack of “soft” skills hampers their performance and proves a barrier to their continued progression to higher levels of responsibility (Newell, 2002: 288). Business Schools offering Masters in Business Administration (MBA) programmes assist in developing managers with not just managerial competence but also with “soft” skills. By delivering educated business managers, these managers through their intellectual skills and community sensitive values, will lead future transformational processes. It is useful and interesting to consider how important emotional intelligence is for effective performance at work. A considerable body of research suggests that an employee’s ability to perceive, identify, and manage emotion provides the basis for the kinds of social and emotional competencies that are important for success in almost any position. Furthermore, as the pace of change increases and the world of work make ever-greater demands on an employee’s cognitive, emotional, and physical resources, this particular set of abilities will become increasingly important (Cherniss, 2000). The primary objective of this study is to determine the perceptions of the Masters in Business Administration (MBA), B-Tech in Business Administration (BBA), Advanced Business Programme (ABP) programmes and the Business School Alumni to determine the overall emotional intelligence profile of students as well as the effective team functions of the syndicate groups. Based on the main findings of the survey, it was concluded that emotional intelligence is an important factor for the NMMU Business School, MBA Unit students. The skills attained through the course work will not only improve team effectiveness in the syndicate group functioning but also enhance their performance in the business environment. The MBA team learning experiences enhances workplace learning as the ability to work in a team and ability to think and act independently are highly desired skills and competencies for success in the workplace.
- Full Text:
- Date Issued: 2007
Enabling and constraining ICT practice in secondary schools: case studies in South Africa
- Hodgkinson-Williams, Cheryl, Siebörger, Ingrid, Terzoli, Alfredo
- Authors: Hodgkinson-Williams, Cheryl , Siebörger, Ingrid , Terzoli, Alfredo
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428923 , vital:72546 , https://www.inderscienceonline.com/doi/epdf/10.1504/IJKL.2007.015551
- Description: The use of Information Communication Technology (ICT) in education is being seen as a way of widening access to education, particularly in developing countries. This paper addresses the issue of ICT implemen-tation in secondary schools and focuses specifically on the practices that enable or constrain the successful implementation of ICT for teach-ing and learning activities. It reflects upon the lessons learned from a collective case study undertaken in 12 of the 13 secondary schools in Grahamstown in the Eastern Cape in South Africa. School principals and designated IT teachers were interviewed and on-site infrastructure audits conducted. This paper identifies a number of key enabling and constraining factors surrounding practical issues, including sufficient hardware, appropriate software and affordable connectivity, sufficient technical support and training, policy-related issues such as the role of national, provincial and school policy, the vital contribution of principal leadership and champion teachers as well as ongoing teacher profes-sional development coupled with a willingness to change.
- Full Text:
- Date Issued: 2007
- Authors: Hodgkinson-Williams, Cheryl , Siebörger, Ingrid , Terzoli, Alfredo
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428923 , vital:72546 , https://www.inderscienceonline.com/doi/epdf/10.1504/IJKL.2007.015551
- Description: The use of Information Communication Technology (ICT) in education is being seen as a way of widening access to education, particularly in developing countries. This paper addresses the issue of ICT implemen-tation in secondary schools and focuses specifically on the practices that enable or constrain the successful implementation of ICT for teach-ing and learning activities. It reflects upon the lessons learned from a collective case study undertaken in 12 of the 13 secondary schools in Grahamstown in the Eastern Cape in South Africa. School principals and designated IT teachers were interviewed and on-site infrastructure audits conducted. This paper identifies a number of key enabling and constraining factors surrounding practical issues, including sufficient hardware, appropriate software and affordable connectivity, sufficient technical support and training, policy-related issues such as the role of national, provincial and school policy, the vital contribution of principal leadership and champion teachers as well as ongoing teacher profes-sional development coupled with a willingness to change.
- Full Text:
- Date Issued: 2007
Endozoochory in the subtropical thicket: comparing effects of species with different digestive systems on seed fate
- Authors: Davis, Shavaughn
- Date: 2007
- Subjects: Seeds -- Dispersal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10714 , http://hdl.handle.net/10948/494 , http://hdl.handle.net/10948/d1012018 , Seeds -- Dispersal
- Description: Endozoochory is an important form of seed dispersal and as such plays a fundamental role in plant population and community ecology. This is especially true in the Subtropical Thicket biome where many plant species are adapted for endozoochory. Endozoochorous seed dispersal is carried out by a wide range of thicket fauna, but changes in the faunal assemblage associated with transformed thicket threatens to disrupt the process of endozoochorous seed dispersal and in turn the regeneration dynamics of thicket plants. Outside of conservation areas, indigenous seed dispersers are often replaced by domestic species, such as goats, which are hypothesized to differ in their seed dispersal efficiencies. The dispersal efficiencies of important thicket seed dispersers that occur in transformed and untransformed thicket were therefore investigated. The influence of gut morphologyphysiology on seed gut passage time, seed mortality and germination in animal species representing different digestive models was measured, as well as the role of black-backed jackal in thicket plant seed dispersal. Black-backed jackal were found to disperse the seeds of few thicket plant species and are therefore not considered important thicket seed dispersers under the climatic conditions prevailing during the study. The average gut passage time of seeds was found to differ significantly between birds and mammals, but not between elephants (hindgut fermentor), goats (ruminant) and pigs (omnivore, foregut fermentor) as was expected considering the differences in their digestive morphology. A significantly shorter gut passage of large seeds compared with small seeds was observed in goats, due to the regurgitation of larger seeds. Seed regurgitation in ruminants may prove to be an important factor contributing to their quality as seed dispersers in transformed thicket. The mortality of seeds was significantly higher in goats than in elephants, probably due to the efficient digestion associated with ruminants. The effect of gut passage on seed germination was not consistent and varied between animal species and across different thicket plant species. It was concluded that seed dispersers that occur in transformed and untransformed thicket differ in their seed dispersal efficiency due, in part, to differences in the nature of their digestive tracts. This has important implications for the process of seed dispersal in thicket, and the rehabilitation of degraded thicket vegetation.
- Full Text:
- Date Issued: 2007
- Authors: Davis, Shavaughn
- Date: 2007
- Subjects: Seeds -- Dispersal
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10714 , http://hdl.handle.net/10948/494 , http://hdl.handle.net/10948/d1012018 , Seeds -- Dispersal
- Description: Endozoochory is an important form of seed dispersal and as such plays a fundamental role in plant population and community ecology. This is especially true in the Subtropical Thicket biome where many plant species are adapted for endozoochory. Endozoochorous seed dispersal is carried out by a wide range of thicket fauna, but changes in the faunal assemblage associated with transformed thicket threatens to disrupt the process of endozoochorous seed dispersal and in turn the regeneration dynamics of thicket plants. Outside of conservation areas, indigenous seed dispersers are often replaced by domestic species, such as goats, which are hypothesized to differ in their seed dispersal efficiencies. The dispersal efficiencies of important thicket seed dispersers that occur in transformed and untransformed thicket were therefore investigated. The influence of gut morphologyphysiology on seed gut passage time, seed mortality and germination in animal species representing different digestive models was measured, as well as the role of black-backed jackal in thicket plant seed dispersal. Black-backed jackal were found to disperse the seeds of few thicket plant species and are therefore not considered important thicket seed dispersers under the climatic conditions prevailing during the study. The average gut passage time of seeds was found to differ significantly between birds and mammals, but not between elephants (hindgut fermentor), goats (ruminant) and pigs (omnivore, foregut fermentor) as was expected considering the differences in their digestive morphology. A significantly shorter gut passage of large seeds compared with small seeds was observed in goats, due to the regurgitation of larger seeds. Seed regurgitation in ruminants may prove to be an important factor contributing to their quality as seed dispersers in transformed thicket. The mortality of seeds was significantly higher in goats than in elephants, probably due to the efficient digestion associated with ruminants. The effect of gut passage on seed germination was not consistent and varied between animal species and across different thicket plant species. It was concluded that seed dispersers that occur in transformed and untransformed thicket differ in their seed dispersal efficiency due, in part, to differences in the nature of their digestive tracts. This has important implications for the process of seed dispersal in thicket, and the rehabilitation of degraded thicket vegetation.
- Full Text:
- Date Issued: 2007
Engaging employees to build a performance culture in Telkom's NCC division
- Authors: Goliath, Elize
- Date: 2007
- Subjects: Performance -- Management , Quality assurance -- Management , Organizational effectiveness , Telkom (Firm : South Africa)
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8591 , http://hdl.handle.net/10948/1051 , Performance -- Management , Quality assurance -- Management , Organizational effectiveness , Telkom (Firm : South Africa)
- Description: Operating as a commercial company since October 1991, Telkom has grown into the largest communications services provider in Africa based on operating revenue and assets. The Group, consisting of the fixed-line company Telkom and a 50 per cent shareholding in mobile operator Vodacom. Telkom has changed its vision to the following: “To be a leading customer and employee centric ICT solutions service provider”. The company has been retrenching staff since 1999 and the staff numbers have reduced significantly from approximately 65 000 people to 25 575 people in 2006. The focus has been on increasing shareholder value and the staff feel that their value has not been recognised. The research paper focused on the extent that employees engaged to build a performance culture in Telkom’s NCC division. The following research methodology was followed: - A literature survey to determine factors or behaviours that will enhance employee engagement in building a performance culture and what Telkom NCC can do to build the workplace that will foster higher levels of employee engagement. - A survey was conducted to determine what the engagement levels of employees are at Telkom NCC, what stops the employees from doing their best and what Telkom NCC division can do to show they care and value their staff as according to their employees by means of a questionnaire. - The findings from the literature study and empirical study would be used to determine to what extent are employees engaged to build a performance culture in Telkom’s NCC division. A self administered questionnaire was used to collect the data required for this research. In conclusion it was said that employee engagement is a partnership between the company and the employees where everyone works together to achieve the business objectives of the company and the personal aspirations of employees. The organization has the responsibility to create the conditions for this to happen (Understanding Employee Engagement, 2004: 2). It was recommended that in order for NCC to enhance their employees attitudes toward the promoters’ team especially in terms of pride, strong attachment, feeling part of the family and motivating employees to do well promoters must concentrate on building relationships with their teams and individual members of the team. Employees must also be given decision making power for implementing the idea. NCC should educate their leaders on the value of recognition and the best way to go about it. In order for employees to grow and be promoted into higher positions, NCC must consider that if positions become available that they first be advertised in the NCC division before it be made available to the rest of the company.
- Full Text:
- Date Issued: 2007
- Authors: Goliath, Elize
- Date: 2007
- Subjects: Performance -- Management , Quality assurance -- Management , Organizational effectiveness , Telkom (Firm : South Africa)
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8591 , http://hdl.handle.net/10948/1051 , Performance -- Management , Quality assurance -- Management , Organizational effectiveness , Telkom (Firm : South Africa)
- Description: Operating as a commercial company since October 1991, Telkom has grown into the largest communications services provider in Africa based on operating revenue and assets. The Group, consisting of the fixed-line company Telkom and a 50 per cent shareholding in mobile operator Vodacom. Telkom has changed its vision to the following: “To be a leading customer and employee centric ICT solutions service provider”. The company has been retrenching staff since 1999 and the staff numbers have reduced significantly from approximately 65 000 people to 25 575 people in 2006. The focus has been on increasing shareholder value and the staff feel that their value has not been recognised. The research paper focused on the extent that employees engaged to build a performance culture in Telkom’s NCC division. The following research methodology was followed: - A literature survey to determine factors or behaviours that will enhance employee engagement in building a performance culture and what Telkom NCC can do to build the workplace that will foster higher levels of employee engagement. - A survey was conducted to determine what the engagement levels of employees are at Telkom NCC, what stops the employees from doing their best and what Telkom NCC division can do to show they care and value their staff as according to their employees by means of a questionnaire. - The findings from the literature study and empirical study would be used to determine to what extent are employees engaged to build a performance culture in Telkom’s NCC division. A self administered questionnaire was used to collect the data required for this research. In conclusion it was said that employee engagement is a partnership between the company and the employees where everyone works together to achieve the business objectives of the company and the personal aspirations of employees. The organization has the responsibility to create the conditions for this to happen (Understanding Employee Engagement, 2004: 2). It was recommended that in order for NCC to enhance their employees attitudes toward the promoters’ team especially in terms of pride, strong attachment, feeling part of the family and motivating employees to do well promoters must concentrate on building relationships with their teams and individual members of the team. Employees must also be given decision making power for implementing the idea. NCC should educate their leaders on the value of recognition and the best way to go about it. In order for employees to grow and be promoted into higher positions, NCC must consider that if positions become available that they first be advertised in the NCC division before it be made available to the rest of the company.
- Full Text:
- Date Issued: 2007
Enhancing phosphorus availability in some phosphate fixing soils of the Transkei region, South Africa using goat manure
- Authors: Gichangi, Elias Maina
- Date: 2007
- Subjects: Phosphorus in agriculture , Soils -- Phosphorus content , Phosphatic fertilizers , Soils -- Phosphorus content -- South Africa -- Transkei
- Language: English
- Type: Thesis , Doctoral , PhD (Soil Science)
- Identifier: vital:11960 , http://hdl.handle.net/10353/80 , Phosphorus in agriculture , Soils -- Phosphorus content , Phosphatic fertilizers , Soils -- Phosphorus content -- South Africa -- Transkei
- Description: Low availability of soil phosphorus (P) caused by strong sorption of P is a major constraint to agricultural production in most South African soils, particularly those from the high rainfall areas. The aim of this study was therefore to investigate whether combined addition of goat manure with inorganic P fertilizers could enhance P availability in some P fixing soils of the Transkei region, South Africa. The study addressed the following specific objectives (i) to assess P sorption capacities and requirements of selected soils and their relationship with selected soil properties and single point sorption test, (ii) to assess the effects of goat manure and lime addition on P sorption properties of selected P fixing soils (iii) to assess the temporal changes in concentration of inorganic and microbial biomass P fractions following application of inorganic fertilizer P with goat manure in a laboratory incubation experiment, and, (iv) to assess the effects of goat manure application with inorganic phosphate on inorganic and microbial biomass P fractions, P uptake and dry matter yield of maize. Sorption maxima (Smax) of seven soils examined ranged from 192.3 to 909.1 (mg P kg-1) and were highly and positively correlated with sorption affinity constant (r = 0.93, p = 0.01) and organic C (r = 0.71, p = 0.01). The amount of P required for maintaining a soil solution concentration of 0.2 mg P l-1 ranged from 2.1 to 123.5 mg P kg-1 soil. Soils collected from Qweqwe (a Cambisol), Qunu (an Acrisol), Ncihane (a Luvisol) and Bethania (a Ferralsol) had lower external P requirement values and were classified as lower sorbers, whereas soils from Ntlonyana (a Planosol), Chevy Chase (a Ferralsol) and Flagstaff (a Ferralsol) were classified as moderate sorbers. The results suggested that P availability could be compromised in 43 percent iii of the soils studied and that measures to mitigate the adverse effects of P sorption were needed to ensure that P is not a limiting factor to crop production, where such soils are found. Goat manure addition at varying rates (5, 10 and 20 tha-1 dry weight basis) to two of the moderately P fixing soils from Chevy Chase and Flagstaff, reduced P sorption maxima (Smax) compared to the control treatment. Phosphate sorption decreased with increasing amounts of goat manure in both soils but the extent of reduction was greater on Chevy Chase soil than on Flagstaff soil. The relative liming effects of the different rates of goat manure followed the order 20 t GM ha-1 > 10 t GM ha-1 > 5 t GM ha-1. In a separate experiment, addition of inorganic P at varying rates (0, 90, 180, and 360 kg P ha-1) to Flagstaff soil increased labile P fractions (resin P, biomass P and NaHCO3-Pi) and the increases were greater when goat manure was co-applied. The control treatments contained only 17.2 and 27.5 mg P kg-1 of resin extractable P in the un-amended and manure amended treatments, respectively which increased to 118.2 and 122.7 mg P kg-1 on day 28 of incubation. Biomass P concentration was increased from 16.8 to 43.9 mg P kg-1 in P alone treatments but the fraction was greatly enhanced with manure addition, increasing it from 32.6 to 97.7 mg P kg-1. NaOH-Pi was the largest extractable Pi fraction and ranged from 144.3 to 250.6 mg P kg-1 and 107.5 to 213.2 mg P kg-1 in the unamended and manure amended treatments, respectively. Dry matter yield and P uptake by maize grown in the glasshouse were highly and significantly (p = 0.05) correlated with the different P fractions in the soil. The correlations followed the order resin P (r = 0.85) > NaOH-Pi (r = 0.85) > NaHCO3-Pi (r = 0.84) >> biomass P (r = 0.56) for dry matter yield at 6 weeks after planting. At 12 weeks after planting, goat manure had iv highly significant effects on resin P and biomass P but had no effect on NaHCO3-Pi and NaOH–Pi. The combination of biomass P, resin P and NaHCO3-Pi explained 75.8 percent of the variation in dry matter yield of which 63.0 percent of the variation was explained by biomass P alone. The greatest increase in biomass P occurred when added P was co-applied with 5 or 10 tha-1 goat manure. The predictive equation for maize dry matter yield (DM) was: DM (g) = 1.897 biomass P + 0.645 resin P (r = 0.73). Resin P was the fraction that was most depleted due to plant uptake and decreased by 56 to 68 percent between the 6th week and the 12th week of sampling indicating that it played a greater role in supplying plant available P. The results therefore suggested that the use of goat manure may allow resource poor farmers to use lower levels of commercial phosphate fertilizers because of its effect to reduce soil P sorption. In addition, higher increases in biomass P due to manure addition observed at lower rates of added P indicated that goat manure has potential for enhancing bioavailability and fertilizer use efficiency of small inorganic P applications.
- Full Text:
- Date Issued: 2007
- Authors: Gichangi, Elias Maina
- Date: 2007
- Subjects: Phosphorus in agriculture , Soils -- Phosphorus content , Phosphatic fertilizers , Soils -- Phosphorus content -- South Africa -- Transkei
- Language: English
- Type: Thesis , Doctoral , PhD (Soil Science)
- Identifier: vital:11960 , http://hdl.handle.net/10353/80 , Phosphorus in agriculture , Soils -- Phosphorus content , Phosphatic fertilizers , Soils -- Phosphorus content -- South Africa -- Transkei
- Description: Low availability of soil phosphorus (P) caused by strong sorption of P is a major constraint to agricultural production in most South African soils, particularly those from the high rainfall areas. The aim of this study was therefore to investigate whether combined addition of goat manure with inorganic P fertilizers could enhance P availability in some P fixing soils of the Transkei region, South Africa. The study addressed the following specific objectives (i) to assess P sorption capacities and requirements of selected soils and their relationship with selected soil properties and single point sorption test, (ii) to assess the effects of goat manure and lime addition on P sorption properties of selected P fixing soils (iii) to assess the temporal changes in concentration of inorganic and microbial biomass P fractions following application of inorganic fertilizer P with goat manure in a laboratory incubation experiment, and, (iv) to assess the effects of goat manure application with inorganic phosphate on inorganic and microbial biomass P fractions, P uptake and dry matter yield of maize. Sorption maxima (Smax) of seven soils examined ranged from 192.3 to 909.1 (mg P kg-1) and were highly and positively correlated with sorption affinity constant (r = 0.93, p = 0.01) and organic C (r = 0.71, p = 0.01). The amount of P required for maintaining a soil solution concentration of 0.2 mg P l-1 ranged from 2.1 to 123.5 mg P kg-1 soil. Soils collected from Qweqwe (a Cambisol), Qunu (an Acrisol), Ncihane (a Luvisol) and Bethania (a Ferralsol) had lower external P requirement values and were classified as lower sorbers, whereas soils from Ntlonyana (a Planosol), Chevy Chase (a Ferralsol) and Flagstaff (a Ferralsol) were classified as moderate sorbers. The results suggested that P availability could be compromised in 43 percent iii of the soils studied and that measures to mitigate the adverse effects of P sorption were needed to ensure that P is not a limiting factor to crop production, where such soils are found. Goat manure addition at varying rates (5, 10 and 20 tha-1 dry weight basis) to two of the moderately P fixing soils from Chevy Chase and Flagstaff, reduced P sorption maxima (Smax) compared to the control treatment. Phosphate sorption decreased with increasing amounts of goat manure in both soils but the extent of reduction was greater on Chevy Chase soil than on Flagstaff soil. The relative liming effects of the different rates of goat manure followed the order 20 t GM ha-1 > 10 t GM ha-1 > 5 t GM ha-1. In a separate experiment, addition of inorganic P at varying rates (0, 90, 180, and 360 kg P ha-1) to Flagstaff soil increased labile P fractions (resin P, biomass P and NaHCO3-Pi) and the increases were greater when goat manure was co-applied. The control treatments contained only 17.2 and 27.5 mg P kg-1 of resin extractable P in the un-amended and manure amended treatments, respectively which increased to 118.2 and 122.7 mg P kg-1 on day 28 of incubation. Biomass P concentration was increased from 16.8 to 43.9 mg P kg-1 in P alone treatments but the fraction was greatly enhanced with manure addition, increasing it from 32.6 to 97.7 mg P kg-1. NaOH-Pi was the largest extractable Pi fraction and ranged from 144.3 to 250.6 mg P kg-1 and 107.5 to 213.2 mg P kg-1 in the unamended and manure amended treatments, respectively. Dry matter yield and P uptake by maize grown in the glasshouse were highly and significantly (p = 0.05) correlated with the different P fractions in the soil. The correlations followed the order resin P (r = 0.85) > NaOH-Pi (r = 0.85) > NaHCO3-Pi (r = 0.84) >> biomass P (r = 0.56) for dry matter yield at 6 weeks after planting. At 12 weeks after planting, goat manure had iv highly significant effects on resin P and biomass P but had no effect on NaHCO3-Pi and NaOH–Pi. The combination of biomass P, resin P and NaHCO3-Pi explained 75.8 percent of the variation in dry matter yield of which 63.0 percent of the variation was explained by biomass P alone. The greatest increase in biomass P occurred when added P was co-applied with 5 or 10 tha-1 goat manure. The predictive equation for maize dry matter yield (DM) was: DM (g) = 1.897 biomass P + 0.645 resin P (r = 0.73). Resin P was the fraction that was most depleted due to plant uptake and decreased by 56 to 68 percent between the 6th week and the 12th week of sampling indicating that it played a greater role in supplying plant available P. The results therefore suggested that the use of goat manure may allow resource poor farmers to use lower levels of commercial phosphate fertilizers because of its effect to reduce soil P sorption. In addition, higher increases in biomass P due to manure addition observed at lower rates of added P indicated that goat manure has potential for enhancing bioavailability and fertilizer use efficiency of small inorganic P applications.
- Full Text:
- Date Issued: 2007
Enlarged arguments in Bantu : evidence from Chichewa
- Authors: Simango, Silvester Ron
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6140 , http://hdl.handle.net/10962/d1011592
- Description: This paper re-examines two types of constructions that have featured in the discussion of possessor ascension in Bantu: one type – an applicative construction – is associated with alienable possession, and the other – non-applicative – is associated with inalienable possession. The study shows that the former expresses affectedness, and that the possessor reading arises only by construal; whereas the latter expresses a part–whole relationship. The paper argues that the two constructions differ in more significant ways than has previously been acknowledged; and that their distinct derivations cannot be captured by traditional possessor ascension (PA) analyses. The putative “alienable” possessor constructions belong to the class of (benefactive) applicative constructions and should be analyzed as such. The paper proposes that the so-called “inalienable” possessor constructions can best be accounted for by positing the existence of “enlarged arguments” wherein the possessum functions as a nominal predicate which more narrowly pinpoints the locus of the action described by the verb.
- Full Text:
- Date Issued: 2007
- Authors: Simango, Silvester Ron
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6140 , http://hdl.handle.net/10962/d1011592
- Description: This paper re-examines two types of constructions that have featured in the discussion of possessor ascension in Bantu: one type – an applicative construction – is associated with alienable possession, and the other – non-applicative – is associated with inalienable possession. The study shows that the former expresses affectedness, and that the possessor reading arises only by construal; whereas the latter expresses a part–whole relationship. The paper argues that the two constructions differ in more significant ways than has previously been acknowledged; and that their distinct derivations cannot be captured by traditional possessor ascension (PA) analyses. The putative “alienable” possessor constructions belong to the class of (benefactive) applicative constructions and should be analyzed as such. The paper proposes that the so-called “inalienable” possessor constructions can best be accounted for by positing the existence of “enlarged arguments” wherein the possessum functions as a nominal predicate which more narrowly pinpoints the locus of the action described by the verb.
- Full Text:
- Date Issued: 2007
Environment and sustainability education in a changing South Africa: A critical historical analysis of outline schemes for defining and guiding learning interactions
- Authors: O'Donoghue, Rob B
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373634 , vital:66708 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122749"
- Description: This paper examines how, in response to emerging risk, methodological narratives for conservation (CE), environmental (EE) and now sustainability education (ESD) were constituted in diverse settings within a changing South African state. After documenting an awareness creation perspective underpinning early extension and experiential activities, the study examines shaping social processes and changing outline schemes for defining and guiding planned learning interactions (methodology) within the broadening field into the present day. The critical historical analysis developed in the study reflects a well-documented shift from early topdown (intervention/extension) to more participatory approaches (collaborative engagement/stewardship). A situated process-mapping of changing orientations also reveals characterising methodological features across the contours of an increasingly diverse field of conservation, environment and sustainability education.
- Full Text:
- Date Issued: 2007
- Authors: O'Donoghue, Rob B
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/373634 , vital:66708 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122749"
- Description: This paper examines how, in response to emerging risk, methodological narratives for conservation (CE), environmental (EE) and now sustainability education (ESD) were constituted in diverse settings within a changing South African state. After documenting an awareness creation perspective underpinning early extension and experiential activities, the study examines shaping social processes and changing outline schemes for defining and guiding planned learning interactions (methodology) within the broadening field into the present day. The critical historical analysis developed in the study reflects a well-documented shift from early topdown (intervention/extension) to more participatory approaches (collaborative engagement/stewardship). A situated process-mapping of changing orientations also reveals characterising methodological features across the contours of an increasingly diverse field of conservation, environment and sustainability education.
- Full Text:
- Date Issued: 2007
Establishing the benefits of implementing an I.T. project management office in the Nelson Mandela Metropolitan area
- Martin, Michael Ronald Charles
- Authors: Martin, Michael Ronald Charles
- Date: 2007
- Subjects: Project management -- South Africa -- Port Elizabeth -- Computer network resources , Information technology -- South Africa -- Port Elizabeth -- Management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9266 , http://hdl.handle.net/10948/558 , Project management -- South Africa -- Port Elizabeth -- Computer network resources , Information technology -- South Africa -- Port Elizabeth -- Management
- Description: The well-known concept of a Project Manager managing an I.T. project in relative isolation is no longer a viable option for organisations that are running numerous projects simultaneously. Due to the enormous costs and risks involved in many of these projects, there needs to be a means to ensure success. This has led to the establishment of the concept of a Project Management Office (PMO). An autonomous business unit that is responsible for managing all projects within an organisation. The need for a Project Management Office (PMO) to effectively manage multiple projects is becoming more and more accepted worldwide. The benefits of a PMO are well documented, but whether these benefits will apply to organisations within the NMM area needed to be investigated. A detailed analysis of the benefits of Project Management and in particular a PMO, have been investigated by means of a literature study. An investigation into the effectiveness of PMO’s in South Africa in general, was conducted by means of a survey targeted at a group of I.T. Project Managers located in all the major centres. A further survey was conducted among local I.T. managers to determine their current level of success and their expectations for the future. When reviewing the expectations of local I.T. management against the performance of Project Managers that are currently operating within PMOs, it is clear that organisations within the NMM area are in need of PMO’s and would certainly benefit from their establishment.
- Full Text:
- Date Issued: 2007
- Authors: Martin, Michael Ronald Charles
- Date: 2007
- Subjects: Project management -- South Africa -- Port Elizabeth -- Computer network resources , Information technology -- South Africa -- Port Elizabeth -- Management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9266 , http://hdl.handle.net/10948/558 , Project management -- South Africa -- Port Elizabeth -- Computer network resources , Information technology -- South Africa -- Port Elizabeth -- Management
- Description: The well-known concept of a Project Manager managing an I.T. project in relative isolation is no longer a viable option for organisations that are running numerous projects simultaneously. Due to the enormous costs and risks involved in many of these projects, there needs to be a means to ensure success. This has led to the establishment of the concept of a Project Management Office (PMO). An autonomous business unit that is responsible for managing all projects within an organisation. The need for a Project Management Office (PMO) to effectively manage multiple projects is becoming more and more accepted worldwide. The benefits of a PMO are well documented, but whether these benefits will apply to organisations within the NMM area needed to be investigated. A detailed analysis of the benefits of Project Management and in particular a PMO, have been investigated by means of a literature study. An investigation into the effectiveness of PMO’s in South Africa in general, was conducted by means of a survey targeted at a group of I.T. Project Managers located in all the major centres. A further survey was conducted among local I.T. managers to determine their current level of success and their expectations for the future. When reviewing the expectations of local I.T. management against the performance of Project Managers that are currently operating within PMOs, it is clear that organisations within the NMM area are in need of PMO’s and would certainly benefit from their establishment.
- Full Text:
- Date Issued: 2007
Estimating erosion of cretaceous-aged kimberlites in the Republic of South Africa through the examination of upper-crustal xenoliths
- Authors: Hanson, Emily Kate
- Date: 2007
- Subjects: Kimberlite -- South Africa , Igneous rocks -- Inclusions -- South Africa , Erosion -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4942 , http://hdl.handle.net/10962/d1005554 , Kimberlite -- South Africa , Igneous rocks -- Inclusions -- South Africa , Erosion -- South Africa
- Description: he estimation of post-emplacement kimberlite erosion in South Africa through the study of upper-crustal xenoliths is relatively unexplored; however the presence of these xenoliths has been recognized for well over 100 years. Post-emplacement erosion levels of a small number of South African kimberlite pipes have been inferred through the study of the degree of country-rock diagenesis, the depth of sill formation, the depth of the initiation of the diatreme and fission track studies. Through these studies, several estimates were proposed for the Group I Kimberley kimberlites. Although the 1400 m estimate of erosion remains widely accepted today, this estimate relies on the presence of Karoo-like basalt xenoliths in the Group I Kimberley kimberlites, as their presence proves that basalt existed in the Kimberley area when the kimberlites were emplaced. Basaltic xenoliths were described during the early stages of mining in Kimberley, though only one of these descriptions suggests that the ‘basaltic’ boulders correlate with the Karoo basalts. Because of the discrepancy between these early documentations of upper-crustal xenoliths and because the occurrence of Karoo-like basalt xenoliths in the Group I Kimberley kimberlites is under question, a re-investigation of the erosion levels and the upper crustal xenolith suites in South African, Cretaceous-aged kimberlites, including Melton Wold, Voorspoed, Roberts Victor, West End, Record Stone Quarry, Finsch, Markt, Frank Smith, Pampoenpoort, Uintjiesberg, Koffiefontein / Ebenheuyser, Monastery, Kimberley (Big Hole), Kamfersdam , Jagersfontein, Kaal Vallei, De Beers, Bultfontein, Lushof, Britstown Cluster, Hebron and Lovedale, was conducted. This study presents the analytical results for upper-crustal sandstone and basalt xenoliths collected from dumps, excavation pits and borehole core at the above-mentioned kimberlites, and demonstrates that they correlate with stratigraphic units of the Karoo Supergroup on the basis of mineral and geochemical compositions. These upper-crustal xenoliths are incorporated into kimberlites and down-rafted to levels below their stratigraphic position during kimberlite emplacement, consequently recording the broad stratigraphy into which each kimberlite is emplaced. Therefore, the Cretaceous lateral extent of the Karoo Supergroup is inferred and post-emplacement erosion estimated by reconstructing the stratigraphy based on upper-crustal xenolith suites for each kimberlite and calculating the total thickness of the now-eroded units. The distribution of sandstone xenoliths indicates that during the Cretaceous the lateral extent of the Dwyka, Ecca and Beaufort Groups encompassed all of the examined kimberlites, while the ‘Stormberg’ Group was constrained to an area outlined by the Voorspoed and Monastery kimberlites. Similarly, basalt xenoliths occur in all of the Group II and transitional (143 – 100 Ma) kimberlites but only in the Group I (90 – 74 Ma) kimberlites that lie within close proximity to the western outcrop margin of the outcrop area of the Drakensberg Group basalts (Lesotho Remnant), namely Monastery, Jagersfontein and Kaal Vallei. This trend implies an eastward-retreat of the inland erosion front of the Karoo basalts between 140 and 90 Ma and subsequent erosion of the underlying sedimentary units. It also suggests that a thicker succession of Karoo strata was present at the time of Group II and transitional kimberlite emplacement and that there has been more post-emplacement erosion in these kimberlites than the younger Group I kimberlites, except for Monastery, Jagersfontein and Kaal Vallei. Estimates are unique to each kimberlite as they are dependent on both stratigraphic location, elevation and present country rock, and range from approximately 1000 – 2500 m for the older kimberlites and less than 700 m to 1400 m for the younger kimberlites. Furthermore, the upper-crustal xenoliths found at the Group I Kimberley kimberlites and the coinciding trend of basalt erosion demonstrate that Karoo basalts were eroded from the Kimberley area by the time the Group I Kimberley kimberlites erupted (~85 Ma). Therefore, basalts are omitted from the Group I Kimberley kimberlites post-emplacement erosion estimate, and the upper Beaufort Group is considered the upper limit of the stratigraphy that was present at the time of the eruption of the Group I Kimberley pipes. Therefore, the erosion estimates decrease from a previous estimate of 1400 m down to 400 to 1100 m, where 850 m is considered a dependable intermediate estimate.
- Full Text:
- Date Issued: 2007
- Authors: Hanson, Emily Kate
- Date: 2007
- Subjects: Kimberlite -- South Africa , Igneous rocks -- Inclusions -- South Africa , Erosion -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4942 , http://hdl.handle.net/10962/d1005554 , Kimberlite -- South Africa , Igneous rocks -- Inclusions -- South Africa , Erosion -- South Africa
- Description: he estimation of post-emplacement kimberlite erosion in South Africa through the study of upper-crustal xenoliths is relatively unexplored; however the presence of these xenoliths has been recognized for well over 100 years. Post-emplacement erosion levels of a small number of South African kimberlite pipes have been inferred through the study of the degree of country-rock diagenesis, the depth of sill formation, the depth of the initiation of the diatreme and fission track studies. Through these studies, several estimates were proposed for the Group I Kimberley kimberlites. Although the 1400 m estimate of erosion remains widely accepted today, this estimate relies on the presence of Karoo-like basalt xenoliths in the Group I Kimberley kimberlites, as their presence proves that basalt existed in the Kimberley area when the kimberlites were emplaced. Basaltic xenoliths were described during the early stages of mining in Kimberley, though only one of these descriptions suggests that the ‘basaltic’ boulders correlate with the Karoo basalts. Because of the discrepancy between these early documentations of upper-crustal xenoliths and because the occurrence of Karoo-like basalt xenoliths in the Group I Kimberley kimberlites is under question, a re-investigation of the erosion levels and the upper crustal xenolith suites in South African, Cretaceous-aged kimberlites, including Melton Wold, Voorspoed, Roberts Victor, West End, Record Stone Quarry, Finsch, Markt, Frank Smith, Pampoenpoort, Uintjiesberg, Koffiefontein / Ebenheuyser, Monastery, Kimberley (Big Hole), Kamfersdam , Jagersfontein, Kaal Vallei, De Beers, Bultfontein, Lushof, Britstown Cluster, Hebron and Lovedale, was conducted. This study presents the analytical results for upper-crustal sandstone and basalt xenoliths collected from dumps, excavation pits and borehole core at the above-mentioned kimberlites, and demonstrates that they correlate with stratigraphic units of the Karoo Supergroup on the basis of mineral and geochemical compositions. These upper-crustal xenoliths are incorporated into kimberlites and down-rafted to levels below their stratigraphic position during kimberlite emplacement, consequently recording the broad stratigraphy into which each kimberlite is emplaced. Therefore, the Cretaceous lateral extent of the Karoo Supergroup is inferred and post-emplacement erosion estimated by reconstructing the stratigraphy based on upper-crustal xenolith suites for each kimberlite and calculating the total thickness of the now-eroded units. The distribution of sandstone xenoliths indicates that during the Cretaceous the lateral extent of the Dwyka, Ecca and Beaufort Groups encompassed all of the examined kimberlites, while the ‘Stormberg’ Group was constrained to an area outlined by the Voorspoed and Monastery kimberlites. Similarly, basalt xenoliths occur in all of the Group II and transitional (143 – 100 Ma) kimberlites but only in the Group I (90 – 74 Ma) kimberlites that lie within close proximity to the western outcrop margin of the outcrop area of the Drakensberg Group basalts (Lesotho Remnant), namely Monastery, Jagersfontein and Kaal Vallei. This trend implies an eastward-retreat of the inland erosion front of the Karoo basalts between 140 and 90 Ma and subsequent erosion of the underlying sedimentary units. It also suggests that a thicker succession of Karoo strata was present at the time of Group II and transitional kimberlite emplacement and that there has been more post-emplacement erosion in these kimberlites than the younger Group I kimberlites, except for Monastery, Jagersfontein and Kaal Vallei. Estimates are unique to each kimberlite as they are dependent on both stratigraphic location, elevation and present country rock, and range from approximately 1000 – 2500 m for the older kimberlites and less than 700 m to 1400 m for the younger kimberlites. Furthermore, the upper-crustal xenoliths found at the Group I Kimberley kimberlites and the coinciding trend of basalt erosion demonstrate that Karoo basalts were eroded from the Kimberley area by the time the Group I Kimberley kimberlites erupted (~85 Ma). Therefore, basalts are omitted from the Group I Kimberley kimberlites post-emplacement erosion estimate, and the upper Beaufort Group is considered the upper limit of the stratigraphy that was present at the time of the eruption of the Group I Kimberley pipes. Therefore, the erosion estimates decrease from a previous estimate of 1400 m down to 400 to 1100 m, where 850 m is considered a dependable intermediate estimate.
- Full Text:
- Date Issued: 2007
Estimating the willingness-to-pay for restoring indigenous vegetation at selected sites in South Africa
- Authors: Tessendorf, Sharon Erica
- Date: 2007
- Subjects: Water resources development -- South Africa , Water-supply -- South Africa , Alien plants -- South Africa , Restoration ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:8999 , http://hdl.handle.net/10948/617 , Water resources development -- South Africa , Water-supply -- South Africa , Alien plants -- South Africa , Restoration ecology -- South Africa
- Description: The Working for Water (WfW) Programme is a public works programme designed to clear South Africa of invasive alien vegetation and to restore lowwater consuming indigenous vegetation in the areas that have been cleared. Funds to clear alien invasives were initially secured on the basis that such a programme would increase water runoff, facilitate biodiversity and ecosystem functioning, and provide social benefits through job creation. The economic merits of the Programme, in terms of increased water yields, has been established in the Western Cape and KwaZulu-Natal, but questioned in the Eastern and Southern Cape. However, there are economic aspects of the studies carried out in the Eastern and Southern Cape that merit more attention than was given them; one of these being the issue of non-water benefits. Preliminary figures emanating from contingent valuation pilot studies conducted at six WfW projects sites indicated that one of these non-water benefits, namely the biodiversity and ecosystem resilience benefit, could be substantial. As such, the primary objective of the present study was to apply the contingent valuation method (CVM) to value people’s preference for indigenous vegetation. This value was intended to serve as a proxy for increased biodiversity and ecosystem resilience at three WfW sites. Despite the controversy surrounding the CVM, it has been found that it is a credible valuation tool. The CVM’s merits lie in its versatility and in the fact that it is the only method available which is capable of obtaining estimates of both nonuse and use values, thus making it applicable for valuing biodiversity. The primary aim of a CVM study is to determine an estimate of the total willingness-to-pay (WTP). In this study, the total WTP figure was calculated by multiplying the median WTP for the local WfW Programme by the total number of user households. The respective total WTP amounts are shown in Table 1. It was anticipated that respondents would be willing to pay more for the national WfW Programme, than for the less inclusive good (i.e. the local WfW Programme). The results correspond with this expectation at the Port Elizabeth and Underberg sites. However, due to strategic factors Worcester respondents were willing to pay more for the local WfW Programme than for the national Programme.
- Full Text:
- Date Issued: 2007
- Authors: Tessendorf, Sharon Erica
- Date: 2007
- Subjects: Water resources development -- South Africa , Water-supply -- South Africa , Alien plants -- South Africa , Restoration ecology -- South Africa
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:8999 , http://hdl.handle.net/10948/617 , Water resources development -- South Africa , Water-supply -- South Africa , Alien plants -- South Africa , Restoration ecology -- South Africa
- Description: The Working for Water (WfW) Programme is a public works programme designed to clear South Africa of invasive alien vegetation and to restore lowwater consuming indigenous vegetation in the areas that have been cleared. Funds to clear alien invasives were initially secured on the basis that such a programme would increase water runoff, facilitate biodiversity and ecosystem functioning, and provide social benefits through job creation. The economic merits of the Programme, in terms of increased water yields, has been established in the Western Cape and KwaZulu-Natal, but questioned in the Eastern and Southern Cape. However, there are economic aspects of the studies carried out in the Eastern and Southern Cape that merit more attention than was given them; one of these being the issue of non-water benefits. Preliminary figures emanating from contingent valuation pilot studies conducted at six WfW projects sites indicated that one of these non-water benefits, namely the biodiversity and ecosystem resilience benefit, could be substantial. As such, the primary objective of the present study was to apply the contingent valuation method (CVM) to value people’s preference for indigenous vegetation. This value was intended to serve as a proxy for increased biodiversity and ecosystem resilience at three WfW sites. Despite the controversy surrounding the CVM, it has been found that it is a credible valuation tool. The CVM’s merits lie in its versatility and in the fact that it is the only method available which is capable of obtaining estimates of both nonuse and use values, thus making it applicable for valuing biodiversity. The primary aim of a CVM study is to determine an estimate of the total willingness-to-pay (WTP). In this study, the total WTP figure was calculated by multiplying the median WTP for the local WfW Programme by the total number of user households. The respective total WTP amounts are shown in Table 1. It was anticipated that respondents would be willing to pay more for the national WfW Programme, than for the less inclusive good (i.e. the local WfW Programme). The results correspond with this expectation at the Port Elizabeth and Underberg sites. However, due to strategic factors Worcester respondents were willing to pay more for the local WfW Programme than for the national Programme.
- Full Text:
- Date Issued: 2007
Ethnicity and nationalism in urban colonial Zimbabwe : Bulawayo, 1950 to 1963
- Authors: Msindo, Enocent
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6149 , http://hdl.handle.net/10962/d1006813 , http://dx.doi.org/10.1017/S0021853707002538
- Description: Zimbabwean historians have not yet fully assessed the interaction of two problematic identities, ethnicity and nationalism, to determine whether the two can work as partners and successfully co-exist. This essay argues that, in Bulawayo during the period studied, ethnicity co-existed with and complemented nationalism rather than the two working as polar opposite identities. Ethnic groups provided both the required leaders who became prominent nationalist figures and the precolonial history, personalities and monuments that sparked the nationalist imagination. From the 1950s, ethnic groups expanded their horizons and provided platforms from which emerging African nationalists launched their agenda. Understanding these interrelationships will reshape our understanding of the workings of these two identities in a cosmopolitan town.
- Full Text:
- Date Issued: 2007
- Authors: Msindo, Enocent
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6149 , http://hdl.handle.net/10962/d1006813 , http://dx.doi.org/10.1017/S0021853707002538
- Description: Zimbabwean historians have not yet fully assessed the interaction of two problematic identities, ethnicity and nationalism, to determine whether the two can work as partners and successfully co-exist. This essay argues that, in Bulawayo during the period studied, ethnicity co-existed with and complemented nationalism rather than the two working as polar opposite identities. Ethnic groups provided both the required leaders who became prominent nationalist figures and the precolonial history, personalities and monuments that sparked the nationalist imagination. From the 1950s, ethnic groups expanded their horizons and provided platforms from which emerging African nationalists launched their agenda. Understanding these interrelationships will reshape our understanding of the workings of these two identities in a cosmopolitan town.
- Full Text:
- Date Issued: 2007
Evaluating compression as an enabler for centralised monitoring in a Next Generation Network
- Otten, Fred, Irwin, Barry V W, Slay, Hannah
- Authors: Otten, Fred , Irwin, Barry V W , Slay, Hannah
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428226 , vital:72495 , https://citeseerx.ist.psu.edu/document?repid=rep1andtype=pdfanddoi=f9ed69db7da44c168082934cd4ea5a413b2bf7f5
- Description: With the emergence of Next Generation Networks and a large number of next generation services, the volume and diversity of information is on the rise. These networks are often large, distributed and consist of het-erogeneous devices. In order to provide effective centralised monitoring and control we need to be able to assemble the relevant data at a cen-tral point. This becomes difficult because of the large quantity of data. We also would like to achieve this using the least amount of bandwidth, and minimise the latency. This paper investigates using compression to enable centralised monitoring and control. It presents the results of ex-periments showing that compression is an effective method of data re-duction, resulting in up to 93.3 percent reduction in bandwidth usage for point-to-point transmission. This paper also describes an architecture that incorporates compression and provides centralised monitoring and control.
- Full Text:
- Date Issued: 2007
- Authors: Otten, Fred , Irwin, Barry V W , Slay, Hannah
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428226 , vital:72495 , https://citeseerx.ist.psu.edu/document?repid=rep1andtype=pdfanddoi=f9ed69db7da44c168082934cd4ea5a413b2bf7f5
- Description: With the emergence of Next Generation Networks and a large number of next generation services, the volume and diversity of information is on the rise. These networks are often large, distributed and consist of het-erogeneous devices. In order to provide effective centralised monitoring and control we need to be able to assemble the relevant data at a cen-tral point. This becomes difficult because of the large quantity of data. We also would like to achieve this using the least amount of bandwidth, and minimise the latency. This paper investigates using compression to enable centralised monitoring and control. It presents the results of ex-periments showing that compression is an effective method of data re-duction, resulting in up to 93.3 percent reduction in bandwidth usage for point-to-point transmission. This paper also describes an architecture that incorporates compression and provides centralised monitoring and control.
- Full Text:
- Date Issued: 2007
Evaluating the impact of the Institutional Repository, or positioning innovation between a rock and a hard place
- Authors: Thomas, G M E
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6988 , http://hdl.handle.net/10962/d1012411
- Description: Repositories remain an innovative but marginalized technology largely because there is no consensus about an agreed set of Performance Indicators (PIs) that demonstrate their overall impact on the research enterprise of our universities. A successful Institutional Repository should be evaluated in terms of the extent to which the open access repository builds a critical mass of scholarly content which is sustained and available through active university community engagement and ongoing scholarly contributions (faculty, researchers & students) that, when managed efficiently and effectively, ultimately strengthen, promote and give visibility to the research enterprise of the institution, and bring benefit to broader society. However, librarians are grappling with what and how best to demonstrate ‘institutional good’ but without clear evidence, assessment is fed by perception based on limited information which leads to diminished impact and value of the facility, a tyranny described as being caught between a rock and a hard place. Using Illuminative Evaluation to design a series of quantitative and qualitative metrics, it is proposed that a distinction be made between significant and secondary Performance Indicators where the former gather evidence to demonstrate the overall effect or impact of the IR on the individual and collective research community.
- Full Text:
- Date Issued: 2007
- Authors: Thomas, G M E
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6988 , http://hdl.handle.net/10962/d1012411
- Description: Repositories remain an innovative but marginalized technology largely because there is no consensus about an agreed set of Performance Indicators (PIs) that demonstrate their overall impact on the research enterprise of our universities. A successful Institutional Repository should be evaluated in terms of the extent to which the open access repository builds a critical mass of scholarly content which is sustained and available through active university community engagement and ongoing scholarly contributions (faculty, researchers & students) that, when managed efficiently and effectively, ultimately strengthen, promote and give visibility to the research enterprise of the institution, and bring benefit to broader society. However, librarians are grappling with what and how best to demonstrate ‘institutional good’ but without clear evidence, assessment is fed by perception based on limited information which leads to diminished impact and value of the facility, a tyranny described as being caught between a rock and a hard place. Using Illuminative Evaluation to design a series of quantitative and qualitative metrics, it is proposed that a distinction be made between significant and secondary Performance Indicators where the former gather evidence to demonstrate the overall effect or impact of the IR on the individual and collective research community.
- Full Text:
- Date Issued: 2007
Evaluation and application of electroanalysis for the determination of antioxidants
- Authors: Ragubeer, Nasheen
- Date: 2007
- Subjects: Antioxidants , Nervous system -- Degeneration , Electrochemical analysis , Marine algae , Natural products , Marine metabolites , Sargassum , Legumes , Nuclear magnetic resonance
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3922 , http://hdl.handle.net/10962/d1003981 , Antioxidants , Nervous system -- Degeneration , Electrochemical analysis , Marine algae , Natural products , Marine metabolites , Sargassum , Legumes , Nuclear magnetic resonance
- Description: The role of antioxidants in the prevention of neurodegenerative diseases has been well documented. The use of synthetic antioxidants has decreased due to the ssociation of these compounds with certain cancers. Thus, the search for novel natural antioxidants has gained much focus in research. Most common methods of determining antioxidant capacity are the radical generated assays and biological assays such as lipid peroxidation and the nitroblue tetrazolium assay. Electrochemical methods have been proposed for the determination of bio-active compounds such as antioxidants. The electrochemical methods of cyclic voltammetry and square wave voltammetry were evaluated for the determination of antioxidant capacity initially examining known antioxidants and then using plant extracts of Sutherlandia frutescens as a case study. The antioxidant properties determined by electrochemical methods were validated utilising the non-biological methods of the DPPH, TEAC, ferrozine and FC assay and biological pharmacological methods. The results indicated that Sutherlandia frutescens contains potent antioxidant compounds that are able to reduce lipid peroxidation. The electrochemical techniques of square wave voltammetry and cyclic voltammetry were applied for the screening of a large number of extracts of various algae for the detection of antioxidant compounds. The results indicated that electrochemistry can be used as a preliminary method for the rapid screening of a large number of crude samples for antioxidant compounds. Electrochemical methods were also evaluated as a method for guiding the isolation and purification of antioxidant metabolites in Sargassum elegans. Solvent partitioning and fractionation of the marine alga allowed for the purification of antioxidant compounds. At each step of purification electrochemical methods were utilized to determine which fractions contained the more potent antioxidant compounds and thus guide further purification. The purified antioxidant compounds were elucidated using NMR to determine the structure of the antioxidant compounds.
- Full Text:
- Date Issued: 2007
- Authors: Ragubeer, Nasheen
- Date: 2007
- Subjects: Antioxidants , Nervous system -- Degeneration , Electrochemical analysis , Marine algae , Natural products , Marine metabolites , Sargassum , Legumes , Nuclear magnetic resonance
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3922 , http://hdl.handle.net/10962/d1003981 , Antioxidants , Nervous system -- Degeneration , Electrochemical analysis , Marine algae , Natural products , Marine metabolites , Sargassum , Legumes , Nuclear magnetic resonance
- Description: The role of antioxidants in the prevention of neurodegenerative diseases has been well documented. The use of synthetic antioxidants has decreased due to the ssociation of these compounds with certain cancers. Thus, the search for novel natural antioxidants has gained much focus in research. Most common methods of determining antioxidant capacity are the radical generated assays and biological assays such as lipid peroxidation and the nitroblue tetrazolium assay. Electrochemical methods have been proposed for the determination of bio-active compounds such as antioxidants. The electrochemical methods of cyclic voltammetry and square wave voltammetry were evaluated for the determination of antioxidant capacity initially examining known antioxidants and then using plant extracts of Sutherlandia frutescens as a case study. The antioxidant properties determined by electrochemical methods were validated utilising the non-biological methods of the DPPH, TEAC, ferrozine and FC assay and biological pharmacological methods. The results indicated that Sutherlandia frutescens contains potent antioxidant compounds that are able to reduce lipid peroxidation. The electrochemical techniques of square wave voltammetry and cyclic voltammetry were applied for the screening of a large number of extracts of various algae for the detection of antioxidant compounds. The results indicated that electrochemistry can be used as a preliminary method for the rapid screening of a large number of crude samples for antioxidant compounds. Electrochemical methods were also evaluated as a method for guiding the isolation and purification of antioxidant metabolites in Sargassum elegans. Solvent partitioning and fractionation of the marine alga allowed for the purification of antioxidant compounds. At each step of purification electrochemical methods were utilized to determine which fractions contained the more potent antioxidant compounds and thus guide further purification. The purified antioxidant compounds were elucidated using NMR to determine the structure of the antioxidant compounds.
- Full Text:
- Date Issued: 2007
Evaluation of fishway designs for use at the ebb and flow region of rivers in the Eastern Cape, South Africa
- Authors: Lewis, Hylton Varian
- Date: 2007
- Subjects: Fishways -- South Africa -- Eastern Cape , Fishways -- Design and construction , Aquatic ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5279 , http://hdl.handle.net/10962/d1005123 , Fishways -- South Africa -- Eastern Cape , Fishways -- Design and construction , Aquatic ecology -- South Africa -- Eastern Cape
- Description: Fishways are devices that are increasingly being used worldwide to assist aquatic biofauna to migrate through man-made barriers such as weirs and large-scale dams that are used for water storage, electricity generation etc. and have a negative impact on both the upstream and downstream movement of aquatic organisms. Fishways are usually low gradient channels with evenly placed chambers which allow such migrating aquatic species minimal stress on their passage over these barriers. Despite the existence of national and regional policies for their provision, their construction has often been inhibited through a lack of local assessment of the available designs, and use of ineffective international designs. As part of a larger national research programme, sponsored by the Water Research Commission, to develop a protocol for fishway design and implementation, this study sought to investigate the suitability of vertical slot and sloping baffle designs to assist the migrations of juvenile catadromic fish species in the ebb and flow region of rivers in the Eastern Cape, South Africa. These fishways were initially tested under controlled conditions at the Experimental Fish Farm at the Department of Ichthyology and Fisheries Science, Rhodes University using various fish species. Using the performance data thus collected they were then installed and monitored in the field for the catadromic Myxus capensis (freshwater mullet) and Monodactylus falciformis (cape moony) migrations during March and November of 2005 at the Kowie River ebb and flow weir. The laboratory tests showed that there was a significantly higher level of migration success in the vertical slot compared with the sloping baffle fishway under all conditions (F=82.157; p<0.001). There was, however, a slow decline in levels of success with increased discharge in the vertical slot fishway. This was in contrast to the sloping baffle design where success increased as discharge increased at a steep gradient (F=74.894; p<0.005). The level of success with the M. capensis was related to the size of the fish for both systems with success increasing from the small to the large fish (F=17.755; p<0.001). For the M. falciformis higher levels of success were found to occur in the vertical slot fishway compared to the sloping baffle fishway (F=11.792; p<0.00086), with no significant differences being found with an increase in discharge. Field data indicated similar trends with higher migration success using the vertical slot fishway. M. capensis were better able to negotiate both devices compared to the M. falciformis and overall levels of success were higher for both species in the field than under laboratory conditions where the migration urge may have declined.
- Full Text:
- Date Issued: 2007
- Authors: Lewis, Hylton Varian
- Date: 2007
- Subjects: Fishways -- South Africa -- Eastern Cape , Fishways -- Design and construction , Aquatic ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5279 , http://hdl.handle.net/10962/d1005123 , Fishways -- South Africa -- Eastern Cape , Fishways -- Design and construction , Aquatic ecology -- South Africa -- Eastern Cape
- Description: Fishways are devices that are increasingly being used worldwide to assist aquatic biofauna to migrate through man-made barriers such as weirs and large-scale dams that are used for water storage, electricity generation etc. and have a negative impact on both the upstream and downstream movement of aquatic organisms. Fishways are usually low gradient channels with evenly placed chambers which allow such migrating aquatic species minimal stress on their passage over these barriers. Despite the existence of national and regional policies for their provision, their construction has often been inhibited through a lack of local assessment of the available designs, and use of ineffective international designs. As part of a larger national research programme, sponsored by the Water Research Commission, to develop a protocol for fishway design and implementation, this study sought to investigate the suitability of vertical slot and sloping baffle designs to assist the migrations of juvenile catadromic fish species in the ebb and flow region of rivers in the Eastern Cape, South Africa. These fishways were initially tested under controlled conditions at the Experimental Fish Farm at the Department of Ichthyology and Fisheries Science, Rhodes University using various fish species. Using the performance data thus collected they were then installed and monitored in the field for the catadromic Myxus capensis (freshwater mullet) and Monodactylus falciformis (cape moony) migrations during March and November of 2005 at the Kowie River ebb and flow weir. The laboratory tests showed that there was a significantly higher level of migration success in the vertical slot compared with the sloping baffle fishway under all conditions (F=82.157; p<0.001). There was, however, a slow decline in levels of success with increased discharge in the vertical slot fishway. This was in contrast to the sloping baffle design where success increased as discharge increased at a steep gradient (F=74.894; p<0.005). The level of success with the M. capensis was related to the size of the fish for both systems with success increasing from the small to the large fish (F=17.755; p<0.001). For the M. falciformis higher levels of success were found to occur in the vertical slot fishway compared to the sloping baffle fishway (F=11.792; p<0.00086), with no significant differences being found with an increase in discharge. Field data indicated similar trends with higher migration success using the vertical slot fishway. M. capensis were better able to negotiate both devices compared to the M. falciformis and overall levels of success were higher for both species in the field than under laboratory conditions where the migration urge may have declined.
- Full Text:
- Date Issued: 2007
Evaluation of the safety and efficacy of topical mometasone furoate formulations
- Authors: Chamboko, Bernadett Vongayi
- Date: 2007
- Subjects: Adrenocortical hormones -- Physiological effect , Drugs -- Testing , Dermatopharmacology , High performance liquid chromatography
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3748 , http://hdl.handle.net/10962/d1003226 , Adrenocortical hormones -- Physiological effect , Drugs -- Testing , Dermatopharmacology , High performance liquid chromatography
- Description: The human skin blanching assay (HSBA) is a well-researched and validated method for the bioequivalence assessment of topical corticosteroids. Traditionally, visual assessment of skin blanching has been used. Such testing methods are not conducive for interlaboratory comparisons. Regulatory bodies prefer less subjective methods of analysis. The FDA released guidelines on the assessment of bioequivalence for topical corticosteroids that recommends the use of a chromameter as a reliable method to measure skin blanching although the use of visual assessment with acceptable validation is also provided for. However, the FDA does not elucidate on the manipulation and handling of the chromameter during skin blanching measurements. The purpose of this project was several fold, which included investigations to standardize the manipulation and handling of a chromameter. In particular, measures to avoid skin whitening resulting from the effects of pressure on the skin during chromameter use were investigated. Other methods of analysis should surpass or at least be comparable to the HSBA if such methods are to be used for the assessment of topical corticosteroids. Microdialysis is a relatively new technique for assessing the rate at which drug penetrates the skin. The advantage of using this method is that there are fewer restrictions for selection of an appropriate study population unlike those required for the HSBA where one has to be both a ‘responder’ and a ‘detector’ for their results to be used in data analysis. Microdialysis was investigated by initially conducting experiments in which microdialysis probes were embedded into topical formulations containing mometasone furoate (MF) and the initial results revealed that relatively low drug was released from the formulations. These results indicated that should microdialysis be applied to measure the in vivo release of MF from such topical formulations following application to the skin, even lower concentrations of MF would likely result in the dialysate, necessitating the need for ultra-high sensitive methods of analysis. Typically, the availability of an appropriate analytical technique such as liquid chromatography coupled with mass spectrometry (LCMS) would be a pre-requisite for such in vivo studies. However, only high-pressure liquid chromatography (HPLC) and other less sensitive equipment was available in the laboratories. The study objectives were therefore focussed on in vitro assessment of the release of MF from topical formulations using microdialysis and Franz cells. In addition, the in vivo release of MF was also studied using the HSBA. Data obtained from the microdialysis experiments were compared with the data obtained from the Franz cell diffusion studies in order to provide information on the pharmaceutical availability of MF from the various topical MF dosage forms. Subsequently, pharmaceutical equivalence was investigated from the comparative pharmaceutical availability data using statistical analysis. An additional objective was to attempt to correlate in vitro with in vivo data (IVIVC) to establish a model that could be used to assess safety and efficacy of generic topical drug products. The in vivo data obtained from the HSBA were processed according to the FDA requirements and these pharmacodynamic data were subsequently compared with the microdialysis and Franz cell results. In summary the objectives of this project were: 1. To develop a system to improve the reproducibility of the use of a Minolta® chromameter and compare this with the standard/normal manipulation and handling of such instruments. 2. To develop and validate an HPLC method for the analysis of MF for use with in vitro diffusion studies using microdialysis and Franz cells. 3. To conduct a comparative HSBA on proprietary MF topical creams from two different countries in accordance with the FDA guidance. 4. To assess the pharmaceutical equivalence of topical formulations containing MF using Franz diffusion cells and in vitro microdialysis. 5. To compare the in vivo data obtained from the HSBA with those obtained in vitro using microdialysis and Franz cells.
- Full Text:
- Date Issued: 2007
- Authors: Chamboko, Bernadett Vongayi
- Date: 2007
- Subjects: Adrenocortical hormones -- Physiological effect , Drugs -- Testing , Dermatopharmacology , High performance liquid chromatography
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3748 , http://hdl.handle.net/10962/d1003226 , Adrenocortical hormones -- Physiological effect , Drugs -- Testing , Dermatopharmacology , High performance liquid chromatography
- Description: The human skin blanching assay (HSBA) is a well-researched and validated method for the bioequivalence assessment of topical corticosteroids. Traditionally, visual assessment of skin blanching has been used. Such testing methods are not conducive for interlaboratory comparisons. Regulatory bodies prefer less subjective methods of analysis. The FDA released guidelines on the assessment of bioequivalence for topical corticosteroids that recommends the use of a chromameter as a reliable method to measure skin blanching although the use of visual assessment with acceptable validation is also provided for. However, the FDA does not elucidate on the manipulation and handling of the chromameter during skin blanching measurements. The purpose of this project was several fold, which included investigations to standardize the manipulation and handling of a chromameter. In particular, measures to avoid skin whitening resulting from the effects of pressure on the skin during chromameter use were investigated. Other methods of analysis should surpass or at least be comparable to the HSBA if such methods are to be used for the assessment of topical corticosteroids. Microdialysis is a relatively new technique for assessing the rate at which drug penetrates the skin. The advantage of using this method is that there are fewer restrictions for selection of an appropriate study population unlike those required for the HSBA where one has to be both a ‘responder’ and a ‘detector’ for their results to be used in data analysis. Microdialysis was investigated by initially conducting experiments in which microdialysis probes were embedded into topical formulations containing mometasone furoate (MF) and the initial results revealed that relatively low drug was released from the formulations. These results indicated that should microdialysis be applied to measure the in vivo release of MF from such topical formulations following application to the skin, even lower concentrations of MF would likely result in the dialysate, necessitating the need for ultra-high sensitive methods of analysis. Typically, the availability of an appropriate analytical technique such as liquid chromatography coupled with mass spectrometry (LCMS) would be a pre-requisite for such in vivo studies. However, only high-pressure liquid chromatography (HPLC) and other less sensitive equipment was available in the laboratories. The study objectives were therefore focussed on in vitro assessment of the release of MF from topical formulations using microdialysis and Franz cells. In addition, the in vivo release of MF was also studied using the HSBA. Data obtained from the microdialysis experiments were compared with the data obtained from the Franz cell diffusion studies in order to provide information on the pharmaceutical availability of MF from the various topical MF dosage forms. Subsequently, pharmaceutical equivalence was investigated from the comparative pharmaceutical availability data using statistical analysis. An additional objective was to attempt to correlate in vitro with in vivo data (IVIVC) to establish a model that could be used to assess safety and efficacy of generic topical drug products. The in vivo data obtained from the HSBA were processed according to the FDA requirements and these pharmacodynamic data were subsequently compared with the microdialysis and Franz cell results. In summary the objectives of this project were: 1. To develop a system to improve the reproducibility of the use of a Minolta® chromameter and compare this with the standard/normal manipulation and handling of such instruments. 2. To develop and validate an HPLC method for the analysis of MF for use with in vitro diffusion studies using microdialysis and Franz cells. 3. To conduct a comparative HSBA on proprietary MF topical creams from two different countries in accordance with the FDA guidance. 4. To assess the pharmaceutical equivalence of topical formulations containing MF using Franz diffusion cells and in vitro microdialysis. 5. To compare the in vivo data obtained from the HSBA with those obtained in vitro using microdialysis and Franz cells.
- Full Text:
- Date Issued: 2007
Evolutionary and biogeographic studies in the genus Kniphofia moench (Asphodelaceae)
- Authors: Ramdhani, Syd
- Date: 2007
- Subjects: Asphodelaceae Asphodelaceae -- Genetics Cladistic analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4220 , http://hdl.handle.net/10962/d1003789
- Description: Kniphofia, a genus of approximately 71 species, is almost entirely African with two species occurring in Madagascar and one in Yemen. Commonly known as ‘red hot pokers’ they are popular among horticulturists. The genus is also well known for its complex alpha taxonomy. To date, no studies have examined the phylogenetic relationships among species or the evolutionary history of the genus, and little work has been done on their biogeography. The main focus of this study was (i) to review the alpha taxonomy, (ii) to assess diversity and endemism in Kniphofia, (iii) to use DNA sequence data to reconstruct a specieslevel phylogeny to understand intra-generic species relationships and evolutionary processes (iv) to use phylogeographic approaches to study the biogeography and evaluate biogeographical patterns, and (v) to assess anatomical variation and determine if anatomical characters are useful for species delimitation. It was found that the genus has six centres of diversity, five of which are centres of endemism. The South African Centre is the most speciose and is also the largest centre of endemism. Kniphofia shows a strong Afromontane grassland affinity in Tropical and East Africa. In South Africa, it is found from high altitudes to coastal habitats, with the most speciose regions being Afromontane grasslands. It is thus not considered to be an Afromontane element, but rather an Afromontane associate. Five major evolutionary lineages were identified using cpDNA sequence data (trnT-L spacer), four of which are southern African. The fifth lineage is represented by material from Madagascar, East and Tropical Africa. The nuclear ITS region failed to provide resolution, as many sequences were identical. The five lineages recovered using cpDNA showed some congruence with geographic origin rather than the taxonomic arrangement based on morphology. All of the species with multiple samples were non-monophyletic. This could be due to hybridisation and/or incomplete lineage sorting. The nested clade analysis, although preliminary, did not completely agree with the phylogenetic analyses. One of the three third level nested clades appears to show fragmentation between the Cape Region, KwaZulu-Natal and northern parts of southern Africa. Furthermore, another nested clades recovered suggest a range expansion and radiation from the Drakensberg into the adjacent Drakensberg-Maputoland-Pondoland transition. Morphological species of Kniphofia exhibited substantial leaf anatomical variation and anatomical characters do not cluster samples into their morphological species. The anatomical results do not fit any geographic pattern, nor do they correspond to the lineages recovered using molecular markers or the nested clades. Leaf anatomical variation does not appear to be influenced by geographical or environmental factors. However, hybridisation may play a role but was not tested in this study. In light of the above findings it is proposed that the evolutionary and biogeographic history of Kniphofia is strongly linked to tectonic events, and Quaternary climatic cycles and vegetation changes. Tectonic events (viz. uplifts) may have resulted in vicariance events that may account for the five cpDNA lineages recovered in phylogenetic analyses, while Quaternary climatic cycles and vegetation changes may have had a more recent impact on evolution and biogeography. It is hypothesised that the ancestral area for Kniphofia was much more widespread when Afromontane grasslands were more extensive during cooler and drier glacial episodes. Kniphofia on the high mountains of Tropical and East Africa would have tracked Afromontane grasslands as they expanded their ranges in cooler periods. While during wetter and warmer interglacial periods Kniphofia would have retreated into refugia on the mountains of Tropical and East Africa, with no gene flow possible between these refugia. In South Africa, where latitude compensates for altitude, Kniphofia may have maintained a distribution that extended into the lowlands even during interglacials. A cyclic climate change hypothesis implies that populations of Kniphofia (at different phases of the climatic cycle) would have experienced periods of contractions and fragmentation followed by periods of range expansion and coalescence or secondary contact. Altitudinal shifting is proposed to be the most likely mechanism for fragmentation and range expansion, and would would possibly promoted hybridisation. Within the five lineages there is evidence for recent differentiation as the branch lengths are short, there are numerous nonmonophyletic species and numerous identical haplotypes (cpDNA and ITS) which collectively indicate a recent radiation in southern Africa. A recent radiation would also account for the taxonomic confusion and difficulty in differentiating morpho-species. These climatic events may also account for the substantial anatomical variation in southern African Kniphofia species.
- Full Text:
- Date Issued: 2007
- Authors: Ramdhani, Syd
- Date: 2007
- Subjects: Asphodelaceae Asphodelaceae -- Genetics Cladistic analysis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4220 , http://hdl.handle.net/10962/d1003789
- Description: Kniphofia, a genus of approximately 71 species, is almost entirely African with two species occurring in Madagascar and one in Yemen. Commonly known as ‘red hot pokers’ they are popular among horticulturists. The genus is also well known for its complex alpha taxonomy. To date, no studies have examined the phylogenetic relationships among species or the evolutionary history of the genus, and little work has been done on their biogeography. The main focus of this study was (i) to review the alpha taxonomy, (ii) to assess diversity and endemism in Kniphofia, (iii) to use DNA sequence data to reconstruct a specieslevel phylogeny to understand intra-generic species relationships and evolutionary processes (iv) to use phylogeographic approaches to study the biogeography and evaluate biogeographical patterns, and (v) to assess anatomical variation and determine if anatomical characters are useful for species delimitation. It was found that the genus has six centres of diversity, five of which are centres of endemism. The South African Centre is the most speciose and is also the largest centre of endemism. Kniphofia shows a strong Afromontane grassland affinity in Tropical and East Africa. In South Africa, it is found from high altitudes to coastal habitats, with the most speciose regions being Afromontane grasslands. It is thus not considered to be an Afromontane element, but rather an Afromontane associate. Five major evolutionary lineages were identified using cpDNA sequence data (trnT-L spacer), four of which are southern African. The fifth lineage is represented by material from Madagascar, East and Tropical Africa. The nuclear ITS region failed to provide resolution, as many sequences were identical. The five lineages recovered using cpDNA showed some congruence with geographic origin rather than the taxonomic arrangement based on morphology. All of the species with multiple samples were non-monophyletic. This could be due to hybridisation and/or incomplete lineage sorting. The nested clade analysis, although preliminary, did not completely agree with the phylogenetic analyses. One of the three third level nested clades appears to show fragmentation between the Cape Region, KwaZulu-Natal and northern parts of southern Africa. Furthermore, another nested clades recovered suggest a range expansion and radiation from the Drakensberg into the adjacent Drakensberg-Maputoland-Pondoland transition. Morphological species of Kniphofia exhibited substantial leaf anatomical variation and anatomical characters do not cluster samples into their morphological species. The anatomical results do not fit any geographic pattern, nor do they correspond to the lineages recovered using molecular markers or the nested clades. Leaf anatomical variation does not appear to be influenced by geographical or environmental factors. However, hybridisation may play a role but was not tested in this study. In light of the above findings it is proposed that the evolutionary and biogeographic history of Kniphofia is strongly linked to tectonic events, and Quaternary climatic cycles and vegetation changes. Tectonic events (viz. uplifts) may have resulted in vicariance events that may account for the five cpDNA lineages recovered in phylogenetic analyses, while Quaternary climatic cycles and vegetation changes may have had a more recent impact on evolution and biogeography. It is hypothesised that the ancestral area for Kniphofia was much more widespread when Afromontane grasslands were more extensive during cooler and drier glacial episodes. Kniphofia on the high mountains of Tropical and East Africa would have tracked Afromontane grasslands as they expanded their ranges in cooler periods. While during wetter and warmer interglacial periods Kniphofia would have retreated into refugia on the mountains of Tropical and East Africa, with no gene flow possible between these refugia. In South Africa, where latitude compensates for altitude, Kniphofia may have maintained a distribution that extended into the lowlands even during interglacials. A cyclic climate change hypothesis implies that populations of Kniphofia (at different phases of the climatic cycle) would have experienced periods of contractions and fragmentation followed by periods of range expansion and coalescence or secondary contact. Altitudinal shifting is proposed to be the most likely mechanism for fragmentation and range expansion, and would would possibly promoted hybridisation. Within the five lineages there is evidence for recent differentiation as the branch lengths are short, there are numerous nonmonophyletic species and numerous identical haplotypes (cpDNA and ITS) which collectively indicate a recent radiation in southern Africa. A recent radiation would also account for the taxonomic confusion and difficulty in differentiating morpho-species. These climatic events may also account for the substantial anatomical variation in southern African Kniphofia species.
- Full Text:
- Date Issued: 2007
Evolving a secure grid-enabled, distributed data warehouse : a standards-based perspective
- Authors: Li, Xiao-Yu
- Date: 2007
- Subjects: Computational grids (Computer systems) , Computer networks -- Security measures , Electronic data processing -- Distributed processing
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9738 , http://hdl.handle.net/10948/544 , Computational grids (Computer systems) , Computer networks -- Security measures , Electronic data processing -- Distributed processing
- Description: As digital data-collection has increased in scale and number, it becomes an important type of resource serving a wide community of researchers. Cross-institutional data-sharing and collaboration introduce a suitable approach to facilitate those research institutions that are suffering the lack of data and related IT infrastructures. Grid computing has become a widely adopted approach to enable cross-institutional resource-sharing and collaboration. It integrates a distributed and heterogeneous collection of locally managed users and resources. This project proposes a distributed data warehouse system, which uses Grid technology to enable data-access and integration, and collaborative operations across multi-distributed institutions in the context of HV/AIDS research. This study is based on wider research into OGSA-based Grid services architecture, comprising a data-analysis system which utilizes a data warehouse, data marts, and near-line operational database that are hosted by distributed institutions. Within this framework, specific patterns for collaboration, interoperability, resource virtualization and security are included. The heterogeneous and dynamic nature of the Grid environment introduces a number of security challenges. This study also concerns a set of particular security aspects, including PKI-based authentication, single sign-on, dynamic delegation, and attribute-based authorization. These mechanisms, as supported by the Globus Toolkit’s Grid Security Infrastructure, are used to enable interoperability and establish trust relationship between various security mechanisms and policies within different institutions; manage credentials; and ensure secure interactions.
- Full Text:
- Date Issued: 2007
- Authors: Li, Xiao-Yu
- Date: 2007
- Subjects: Computational grids (Computer systems) , Computer networks -- Security measures , Electronic data processing -- Distributed processing
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9738 , http://hdl.handle.net/10948/544 , Computational grids (Computer systems) , Computer networks -- Security measures , Electronic data processing -- Distributed processing
- Description: As digital data-collection has increased in scale and number, it becomes an important type of resource serving a wide community of researchers. Cross-institutional data-sharing and collaboration introduce a suitable approach to facilitate those research institutions that are suffering the lack of data and related IT infrastructures. Grid computing has become a widely adopted approach to enable cross-institutional resource-sharing and collaboration. It integrates a distributed and heterogeneous collection of locally managed users and resources. This project proposes a distributed data warehouse system, which uses Grid technology to enable data-access and integration, and collaborative operations across multi-distributed institutions in the context of HV/AIDS research. This study is based on wider research into OGSA-based Grid services architecture, comprising a data-analysis system which utilizes a data warehouse, data marts, and near-line operational database that are hosted by distributed institutions. Within this framework, specific patterns for collaboration, interoperability, resource virtualization and security are included. The heterogeneous and dynamic nature of the Grid environment introduces a number of security challenges. This study also concerns a set of particular security aspects, including PKI-based authentication, single sign-on, dynamic delegation, and attribute-based authorization. These mechanisms, as supported by the Globus Toolkit’s Grid Security Infrastructure, are used to enable interoperability and establish trust relationship between various security mechanisms and policies within different institutions; manage credentials; and ensure secure interactions.
- Full Text:
- Date Issued: 2007
Excited state dynamics of zinc and aluminum phthalocyanine carboxylates
- Idowu, Mopelola, Ogunsipe, Abimbola, Nyokong, Tebello
- Authors: Idowu, Mopelola , Ogunsipe, Abimbola , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/271228 , vital:54523 , xlink:href="https://doi.org/10.1016/j.saa.2007.01.025"
- Description: Photophysical parameters for zinc and aluminium tetracarboxylphthalocyanines (ZnTCPc and AlTCPc, respectively) and their octacarboxy substituted counterparts (ZnOCPc and AlOCPc) were studied. Data for the fluorescence quenching of the complexes by benzoquinone (BQ) were treated using the Stern–Volmer analysis, and the quenching was found to follow a diffusion-controlled (dynamic) bimolecular mechanism. Theoretical values of bimolecular rate constant for complex-BQ interactions were determined using the Stokes–Einstein–Smoluchowski model; and the values, together with the Stern–Volmer quenching constants were used in calculating the fluorescence lifetimes of the complexes. The thermodynamics of the MPc-BQ interaction, in terms of solvent reorientation energy is also discussed.
- Full Text:
- Date Issued: 2007
- Authors: Idowu, Mopelola , Ogunsipe, Abimbola , Nyokong, Tebello
- Date: 2007
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/271228 , vital:54523 , xlink:href="https://doi.org/10.1016/j.saa.2007.01.025"
- Description: Photophysical parameters for zinc and aluminium tetracarboxylphthalocyanines (ZnTCPc and AlTCPc, respectively) and their octacarboxy substituted counterparts (ZnOCPc and AlOCPc) were studied. Data for the fluorescence quenching of the complexes by benzoquinone (BQ) were treated using the Stern–Volmer analysis, and the quenching was found to follow a diffusion-controlled (dynamic) bimolecular mechanism. Theoretical values of bimolecular rate constant for complex-BQ interactions were determined using the Stokes–Einstein–Smoluchowski model; and the values, together with the Stern–Volmer quenching constants were used in calculating the fluorescence lifetimes of the complexes. The thermodynamics of the MPc-BQ interaction, in terms of solvent reorientation energy is also discussed.
- Full Text:
- Date Issued: 2007