Deriving narrow syntax through constraints on information structure : a parallel between linguistic models of displacement and database theory
- Authors: De Vos, Mark A
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6142 , http://hdl.handle.net/10962/d1011594
- Description: This paper presents a research program for normalization-driven syntax. It takes the Minimalist research agenda as a starting point (Chomsky 1995. The Minimalist Program. MIT Press, Cambridge MA.) and explores the question of how the CI interface determines syntactic operations. The proposal provides specific content to the notion of bare output conditions and the nature of the CI interface. It does so by drawing on the tools provided by Relational Theory, a branch of set-theoretic mathematics, and Database Theory, a branch of computer science. It is demonstrated that core components of Narrow Syntax (phrase structure, selection and AGREE) are all definable in terms of Relational Theory. Then, it is shown that the process of relation optimization, or normalization, can derive chain formation. The article concludes with two speculations on the implementation of phases within a normalization-driven grammar and the implications of such a system for the learnability of the lexicon.
- Full Text:
- Date Issued: 2008
- Authors: De Vos, Mark A
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6142 , http://hdl.handle.net/10962/d1011594
- Description: This paper presents a research program for normalization-driven syntax. It takes the Minimalist research agenda as a starting point (Chomsky 1995. The Minimalist Program. MIT Press, Cambridge MA.) and explores the question of how the CI interface determines syntactic operations. The proposal provides specific content to the notion of bare output conditions and the nature of the CI interface. It does so by drawing on the tools provided by Relational Theory, a branch of set-theoretic mathematics, and Database Theory, a branch of computer science. It is demonstrated that core components of Narrow Syntax (phrase structure, selection and AGREE) are all definable in terms of Relational Theory. Then, it is shown that the process of relation optimization, or normalization, can derive chain formation. The article concludes with two speculations on the implementation of phases within a normalization-driven grammar and the implications of such a system for the learnability of the lexicon.
- Full Text:
- Date Issued: 2008
Designing accessible portals in South Africa: a case study
- Authors: Meyer, Shaun
- Date: 2008
- Subjects: Web portals -- South Africa -- Port Elizabeth , Web site development -- South Africa -- Port Elizabeth , Internet programming , Web sites -- Design
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9782 , http://hdl.handle.net/10948/770 , Web portals -- South Africa -- Port Elizabeth , Web site development -- South Africa -- Port Elizabeth , Internet programming , Web sites -- Design
- Description: Web portals are considered “gateways” to the World Wide Web. These portals are becoming very popular entry points to the Web by offering important services such as email, news, weather reports, course notes and general information. In addition, some portal sites allow users the option of customising the site according to their personal interests. However, disabled and elderly people encounter many accessibility and usability barriers while accessing web portals. A preliminary review of a university portal was conducted to identify some of these accessibility problems. This treatise presents an overview of the processes to be followed when conducting an accessibility and usability evaluation. In addition, it mentions some guidelines to be considered when specifically designing portals for use by many different users from varying backgrounds.
- Full Text:
- Date Issued: 2008
- Authors: Meyer, Shaun
- Date: 2008
- Subjects: Web portals -- South Africa -- Port Elizabeth , Web site development -- South Africa -- Port Elizabeth , Internet programming , Web sites -- Design
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9782 , http://hdl.handle.net/10948/770 , Web portals -- South Africa -- Port Elizabeth , Web site development -- South Africa -- Port Elizabeth , Internet programming , Web sites -- Design
- Description: Web portals are considered “gateways” to the World Wide Web. These portals are becoming very popular entry points to the Web by offering important services such as email, news, weather reports, course notes and general information. In addition, some portal sites allow users the option of customising the site according to their personal interests. However, disabled and elderly people encounter many accessibility and usability barriers while accessing web portals. A preliminary review of a university portal was conducted to identify some of these accessibility problems. This treatise presents an overview of the processes to be followed when conducting an accessibility and usability evaluation. In addition, it mentions some guidelines to be considered when specifically designing portals for use by many different users from varying backgrounds.
- Full Text:
- Date Issued: 2008
Designing and implementing a new pulsar timer for the Hartebeesthoek Radio Astronomy Observatory
- Authors: Youthed, Andrew David
- Date: 2008
- Subjects: Astronomical observatories , Radio astronomy , Pulsars , Astronomical instruments , Reduced instruction set computers , Random access memory
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5458 , http://hdl.handle.net/10962/d1005243 , Astronomical observatories , Radio astronomy , Pulsars , Astronomical instruments , Reduced instruction set computers , Random access memory
- Description: This thesis outlines the design and implementation of a single channel, dual polarization pulsar timing instrument for the Hartebeesthoek Radio Astronomy Observatory (HartRAO). The new timer is designed to be an improved, temporary replacement for the existing device which has been in operation for over 20 years. The existing device is no longer reliable and is di±cult to maintain. The new pulsar timer is designed to provide improved functional- ity, higher sampling speed, greater pulse resolution, more °exibility and easier maintenance over the existing device. The new device is also designed to keeping changes to the observation system to a minimum until a full de-dispersion timer can be implemented at theobservatory. The design makes use of an 8-bit Reduced Instruction Set Computer (RISC) micro-processor with external Random Access Memory (RAM). The instrument includes an IEEE-488 subsystem for interfacing the pulsar timer to the observation computer system. The microcontroller software is written in assembler code to ensure optimal loop execution speed and deterministic code execution for the system. The design path is discussed and problems encountered during the design process are highlighted. Final testing of the new instrument indicates an improvement in the sam- pling rate of 13.6 times and a significant reduction in 60Hz interference over the existing instrument.
- Full Text:
- Date Issued: 2008
- Authors: Youthed, Andrew David
- Date: 2008
- Subjects: Astronomical observatories , Radio astronomy , Pulsars , Astronomical instruments , Reduced instruction set computers , Random access memory
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5458 , http://hdl.handle.net/10962/d1005243 , Astronomical observatories , Radio astronomy , Pulsars , Astronomical instruments , Reduced instruction set computers , Random access memory
- Description: This thesis outlines the design and implementation of a single channel, dual polarization pulsar timing instrument for the Hartebeesthoek Radio Astronomy Observatory (HartRAO). The new timer is designed to be an improved, temporary replacement for the existing device which has been in operation for over 20 years. The existing device is no longer reliable and is di±cult to maintain. The new pulsar timer is designed to provide improved functional- ity, higher sampling speed, greater pulse resolution, more °exibility and easier maintenance over the existing device. The new device is also designed to keeping changes to the observation system to a minimum until a full de-dispersion timer can be implemented at theobservatory. The design makes use of an 8-bit Reduced Instruction Set Computer (RISC) micro-processor with external Random Access Memory (RAM). The instrument includes an IEEE-488 subsystem for interfacing the pulsar timer to the observation computer system. The microcontroller software is written in assembler code to ensure optimal loop execution speed and deterministic code execution for the system. The design path is discussed and problems encountered during the design process are highlighted. Final testing of the new instrument indicates an improvement in the sam- pling rate of 13.6 times and a significant reduction in 60Hz interference over the existing instrument.
- Full Text:
- Date Issued: 2008
Determinants of household food security in the semi-arid areas of Zimbabwe: a case study of irrigation and non-irrigation farmers in Lupane and Hwange districts
- Authors: Sikwela, Misery Mpuzu
- Date: 2008
- Subjects: Food -- Safety measures , Irrigation farming -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11163 , http://hdl.handle.net/10353/90 , Food -- Safety measures , Irrigation farming -- Zimbabwe
- Description: Lupane and Hwange districts fall under natural region IV and V and lie in the semi-arid regions of Zimbabwe with low and erratic mean annual rainfall not exceeding 600mm. Seventy percent of Zimbabwe’s population lives in communal areas, whose livelihood is based on agriculture. The communities in these areas mainly practice mixed farming systems. However, crop production is constrained by water availability and suitable production techniques. As a result households in these areas are experiencing worsening levels of household food insecurity. Two irrigation schemes were identified for this study and these are located in these two districts. Tshongokwe irrigation scheme is located in Lupane district and Lukosi irrigation scheme is located in Hwange district and these irrigation schemes are about 25 hectares in size. Lupane and Hwange districts are considered to be one of the most food insecure areas in the country because of the frequent droughts and unreliable rainfall in the region. The major tool of enquiry in this study was the questionnaire which was used to collect data from the households that farm on irrigated land and those that farm on dryland farming. Household and farm characteristics were collected using structured questionnaires with the help of locally recruited and trained enumerators. Agricultural production, household consumption and marketing of agricultural produce were accessed using the questionnaire to establish problems experienced by farmers. The main objective of this study was to investigate the determinants of household food security using a logistic regression model. The model was initially fitted with thirteen variables, selected from factors identified by previous researchers that affect food security in communal areas. Six variables were found to be significant at 1, 5 and 10 percent significance level and all had the expected signs except farm size. These factors include access to irrigation, farm size, cattle ownership, fertilizer application, household size and per capita aggregate production. The results obtained were further analyzed to compute partial effects on continuous variables and change in probabilities on the discrete variables for the significant factors in the logistic regression model. Analysis of partial effects revealed that household size, farm size, cattle ownership and per capita aggregate production lead to a greater probability of household being food secure. Change in probability results showed that having access to irrigation and using fertilizer can increase the probability of household being food secure The findings of this study highlight a positive and significant relationship between access to irrigation, fertilizer application, cattle ownership, per capita aggregate production to household food security. Household size and farm size have a negative and significant relationship on household food security. This study shows the effectiveness of irrigated farming over dryland farming in the semi-arid areas. The results show increased agricultural production, crop diversification and higher incomes from irrigation farming as compared to dry land farming. Irrigation farming has enabled many households to diversify their source of income and generate more income. Irrigation has enabled households with irrigation not only to feed themselves throughout the year but also to invest on non-agricultural goods and services from incomes received from crop sales Based on the results from the logistic regression model, it can be concluded that household size, farm size, per capita aggregate production, cattle ownership, fertilizer application and access to irrigation have a positive effect on household food security and the magnitude of changes in conditional probabilities have an impact on household food security.
- Full Text:
- Date Issued: 2008
- Authors: Sikwela, Misery Mpuzu
- Date: 2008
- Subjects: Food -- Safety measures , Irrigation farming -- Zimbabwe
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11163 , http://hdl.handle.net/10353/90 , Food -- Safety measures , Irrigation farming -- Zimbabwe
- Description: Lupane and Hwange districts fall under natural region IV and V and lie in the semi-arid regions of Zimbabwe with low and erratic mean annual rainfall not exceeding 600mm. Seventy percent of Zimbabwe’s population lives in communal areas, whose livelihood is based on agriculture. The communities in these areas mainly practice mixed farming systems. However, crop production is constrained by water availability and suitable production techniques. As a result households in these areas are experiencing worsening levels of household food insecurity. Two irrigation schemes were identified for this study and these are located in these two districts. Tshongokwe irrigation scheme is located in Lupane district and Lukosi irrigation scheme is located in Hwange district and these irrigation schemes are about 25 hectares in size. Lupane and Hwange districts are considered to be one of the most food insecure areas in the country because of the frequent droughts and unreliable rainfall in the region. The major tool of enquiry in this study was the questionnaire which was used to collect data from the households that farm on irrigated land and those that farm on dryland farming. Household and farm characteristics were collected using structured questionnaires with the help of locally recruited and trained enumerators. Agricultural production, household consumption and marketing of agricultural produce were accessed using the questionnaire to establish problems experienced by farmers. The main objective of this study was to investigate the determinants of household food security using a logistic regression model. The model was initially fitted with thirteen variables, selected from factors identified by previous researchers that affect food security in communal areas. Six variables were found to be significant at 1, 5 and 10 percent significance level and all had the expected signs except farm size. These factors include access to irrigation, farm size, cattle ownership, fertilizer application, household size and per capita aggregate production. The results obtained were further analyzed to compute partial effects on continuous variables and change in probabilities on the discrete variables for the significant factors in the logistic regression model. Analysis of partial effects revealed that household size, farm size, cattle ownership and per capita aggregate production lead to a greater probability of household being food secure. Change in probability results showed that having access to irrigation and using fertilizer can increase the probability of household being food secure The findings of this study highlight a positive and significant relationship between access to irrigation, fertilizer application, cattle ownership, per capita aggregate production to household food security. Household size and farm size have a negative and significant relationship on household food security. This study shows the effectiveness of irrigated farming over dryland farming in the semi-arid areas. The results show increased agricultural production, crop diversification and higher incomes from irrigation farming as compared to dry land farming. Irrigation farming has enabled many households to diversify their source of income and generate more income. Irrigation has enabled households with irrigation not only to feed themselves throughout the year but also to invest on non-agricultural goods and services from incomes received from crop sales Based on the results from the logistic regression model, it can be concluded that household size, farm size, per capita aggregate production, cattle ownership, fertilizer application and access to irrigation have a positive effect on household food security and the magnitude of changes in conditional probabilities have an impact on household food security.
- Full Text:
- Date Issued: 2008
Determination and validation of ethno-veterinary practices used as alternatives in controlling cattle ticks by resource-limited farmers in the Eastern Cape Province, South Africa
- Authors: Moyo, Busani
- Date: 2008
- Subjects: Traditional veterinary medicine -- South Africa -- Eastern Cape Province , Ethnozoology -- South Africa -- Eastern Cape Province , Ticks -- South Africa -- Eastern Cape Province
- Language: English
- Type: Thesis , Masters , MSc Agric (Animal Science)
- Identifier: vital:11806 , http://hdl.handle.net/10353/165 , Traditional veterinary medicine -- South Africa -- Eastern Cape Province , Ethnozoology -- South Africa -- Eastern Cape Province , Ticks -- South Africa -- Eastern Cape Province
- Description: Ticks are the most common external parasites of economic importance in the livestock farming sector of Southern Africa. They are vectors of tick-borne diseases and are commonly controlled using conventional acaricides, which are expensive and not readily available to resource-limited farmers. As a result many resource-limited farmers resort to use of alternative materials to control ticks on their livestock. Tick resistance to acaricide is an increasing problem in Southern Africa and poses a real economic threat to livestock and veterinary pharmaceutical industries. The objective of this study was to document and validate the ethno-veterinary remedies used as alternative methods of controlling cattle ticks by resource-limited farmers. A questionnaire survey was conducted in May 2007, at Qolora by-Sea and Nontshinga in Centane district, to determine tick control methods used by resource limited farmers in the Amathole District Municipality of the Eastern Cape Province, South Africa. Furthermore, in vitro and in vivo experiments were done to validate the acaricidal properties of ethnoveterinary remedies used by resource-limited farmers. Ticks were reported to be a major problem, transmitting diseases like anaplasmosis (89.8%), babesiosis (55.9%) and ehrlichiosis (16.9%), they also cause wounds that predispose cattle to screwworm infestation, tick worry and teat damage. All farmers used acaricides and dipping tanks provided by the government to control ticks, as the main tick control method. However, the majority (94.9%) were of the opinion that the dip wash was not effective in controlling ticks. As a result, farmers complemented the government dipping service with use of own initiatives like spraying with conventional acaricides (22%), household disinfectants such as Jeyes fluid (18.6%), used engine oil (10.2%), chickens feeding on ticks (5.1%), manual iv removal (5.1%), and pouricides (1.7%). In addition, some farmers also use plants (6.8%), mainly the leaf of Aloe ferox and the bark of Ptaeroxylon obliquum. The in vitro repellency models showed Jeyes fluid (76.8 and 100% concentrations) and P. obliquum (40%) had repellent properties that lasted 6 hours and 40 minutes respectively while that of, Tabard (35% diethyltoluamide) positive control, lasted for 4 hours when applied against nymphal stages of Rhipicephalus sanguineus ticks. In the contact bio-assay, undiluted used engine oil, T. minuta oil (50%), Ektoban® (Cymiazol 17.5% and cypermethrin 2.5%) and Jeyes fluid (76.8%) caused higher tick mortality of more than 86%. Other materials (A. ferox, Lantana camara and Tagetes minuta) had no repellence and acaricidal properties. In the in vivo study, Jeyes fluid at a concentration of 76.8% and used engine oil displayed efficacy of 71 and 76.4% respectively which was similar to that of the positive control Ektoban® at 97.8% tick load reduction. Among plant materials L. camara at 40% concentrations had an efficacy of 57% while A. ferox, P. obliquum and T. minuta were not effective at all. The remedies used by resource-limited farmers to control ticks vary in efficacy. Their ability to reduce tick load on cattle appears to be promising and a welcome development as their use could probably reduce tick burdens in cattle with less expenditure. However, further investigations need to be done before they are recommended for use. Despite being effective some of the materials have potential toxic effects in animals and also cause environmental contamination and I recommend used engine oil, Jeyes fluid and L. camara for further testing as they showed some efficacy compared to other remedies.
- Full Text:
- Date Issued: 2008
- Authors: Moyo, Busani
- Date: 2008
- Subjects: Traditional veterinary medicine -- South Africa -- Eastern Cape Province , Ethnozoology -- South Africa -- Eastern Cape Province , Ticks -- South Africa -- Eastern Cape Province
- Language: English
- Type: Thesis , Masters , MSc Agric (Animal Science)
- Identifier: vital:11806 , http://hdl.handle.net/10353/165 , Traditional veterinary medicine -- South Africa -- Eastern Cape Province , Ethnozoology -- South Africa -- Eastern Cape Province , Ticks -- South Africa -- Eastern Cape Province
- Description: Ticks are the most common external parasites of economic importance in the livestock farming sector of Southern Africa. They are vectors of tick-borne diseases and are commonly controlled using conventional acaricides, which are expensive and not readily available to resource-limited farmers. As a result many resource-limited farmers resort to use of alternative materials to control ticks on their livestock. Tick resistance to acaricide is an increasing problem in Southern Africa and poses a real economic threat to livestock and veterinary pharmaceutical industries. The objective of this study was to document and validate the ethno-veterinary remedies used as alternative methods of controlling cattle ticks by resource-limited farmers. A questionnaire survey was conducted in May 2007, at Qolora by-Sea and Nontshinga in Centane district, to determine tick control methods used by resource limited farmers in the Amathole District Municipality of the Eastern Cape Province, South Africa. Furthermore, in vitro and in vivo experiments were done to validate the acaricidal properties of ethnoveterinary remedies used by resource-limited farmers. Ticks were reported to be a major problem, transmitting diseases like anaplasmosis (89.8%), babesiosis (55.9%) and ehrlichiosis (16.9%), they also cause wounds that predispose cattle to screwworm infestation, tick worry and teat damage. All farmers used acaricides and dipping tanks provided by the government to control ticks, as the main tick control method. However, the majority (94.9%) were of the opinion that the dip wash was not effective in controlling ticks. As a result, farmers complemented the government dipping service with use of own initiatives like spraying with conventional acaricides (22%), household disinfectants such as Jeyes fluid (18.6%), used engine oil (10.2%), chickens feeding on ticks (5.1%), manual iv removal (5.1%), and pouricides (1.7%). In addition, some farmers also use plants (6.8%), mainly the leaf of Aloe ferox and the bark of Ptaeroxylon obliquum. The in vitro repellency models showed Jeyes fluid (76.8 and 100% concentrations) and P. obliquum (40%) had repellent properties that lasted 6 hours and 40 minutes respectively while that of, Tabard (35% diethyltoluamide) positive control, lasted for 4 hours when applied against nymphal stages of Rhipicephalus sanguineus ticks. In the contact bio-assay, undiluted used engine oil, T. minuta oil (50%), Ektoban® (Cymiazol 17.5% and cypermethrin 2.5%) and Jeyes fluid (76.8%) caused higher tick mortality of more than 86%. Other materials (A. ferox, Lantana camara and Tagetes minuta) had no repellence and acaricidal properties. In the in vivo study, Jeyes fluid at a concentration of 76.8% and used engine oil displayed efficacy of 71 and 76.4% respectively which was similar to that of the positive control Ektoban® at 97.8% tick load reduction. Among plant materials L. camara at 40% concentrations had an efficacy of 57% while A. ferox, P. obliquum and T. minuta were not effective at all. The remedies used by resource-limited farmers to control ticks vary in efficacy. Their ability to reduce tick load on cattle appears to be promising and a welcome development as their use could probably reduce tick burdens in cattle with less expenditure. However, further investigations need to be done before they are recommended for use. Despite being effective some of the materials have potential toxic effects in animals and also cause environmental contamination and I recommend used engine oil, Jeyes fluid and L. camara for further testing as they showed some efficacy compared to other remedies.
- Full Text:
- Date Issued: 2008
Developing a business model for a community radio station in Port Elizabeth: a case study
- Ngcezula, Anthony Thamsanqa "Delite"
- Authors: Ngcezula, Anthony Thamsanqa "Delite"
- Date: 2008
- Subjects: Radio in community development , Radio broadcasting -- South Africa , Community radio
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8720 , http://hdl.handle.net/10948/906 , Radio in community development , Radio broadcasting -- South Africa , Community radio
- Description: The purpose of this treatise is a development of a suitable model for a community radio station which would lead to operational effectiveness and ensure sustainability. The treatise has three phases namely a theoretical phase, a narration phase and an integration phase. Firstly, in the theoretical phase the research study investigates what the literature review reveals about community radio stations and business models. This treatise argues that a total dependency of community radio stations on donor funding leads to operational ineffectiveness which threatens their sustainability. The treatise also argues that a business model could be adapted for a community radio station by identifying the business issues which the literature review revealed, and use these to deconstruct a theoretical business model. Secondly, in the narrative phase the research study investigates the important business issues for a selected community radio station. The treatise argues the board and management of this selected community radio station revealed additional business issues of operations and gave different ratings to business issues which are important in their operations. Thirdly, in the integration phase, the theoretical model deconstructed in the theoretical phase, was revised by including additional business issues of operations revealed in the narrative phase. The research study concludes that this revised model is a suitable business model for a community radio station and can lead to operational effectiveness and ensure sustainability.
- Full Text:
- Date Issued: 2008
- Authors: Ngcezula, Anthony Thamsanqa "Delite"
- Date: 2008
- Subjects: Radio in community development , Radio broadcasting -- South Africa , Community radio
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8720 , http://hdl.handle.net/10948/906 , Radio in community development , Radio broadcasting -- South Africa , Community radio
- Description: The purpose of this treatise is a development of a suitable model for a community radio station which would lead to operational effectiveness and ensure sustainability. The treatise has three phases namely a theoretical phase, a narration phase and an integration phase. Firstly, in the theoretical phase the research study investigates what the literature review reveals about community radio stations and business models. This treatise argues that a total dependency of community radio stations on donor funding leads to operational ineffectiveness which threatens their sustainability. The treatise also argues that a business model could be adapted for a community radio station by identifying the business issues which the literature review revealed, and use these to deconstruct a theoretical business model. Secondly, in the narrative phase the research study investigates the important business issues for a selected community radio station. The treatise argues the board and management of this selected community radio station revealed additional business issues of operations and gave different ratings to business issues which are important in their operations. Thirdly, in the integration phase, the theoretical model deconstructed in the theoretical phase, was revised by including additional business issues of operations revealed in the narrative phase. The research study concludes that this revised model is a suitable business model for a community radio station and can lead to operational effectiveness and ensure sustainability.
- Full Text:
- Date Issued: 2008
Developing a long-term strategy for a selected small transport entrepreneur
- Authors: Burgins, David Christopher
- Date: 2008
- Subjects: Transportation -- South Africa -- Port Elizabeth -- Planning , Transportation and state -- South Africa -- Port Elizabeth , Transportation -- South Africa -- Port Elizabeth -- Finance
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8714 , http://hdl.handle.net/10948/929 , Transportation -- South Africa -- Port Elizabeth -- Planning , Transportation and state -- South Africa -- Port Elizabeth , Transportation -- South Africa -- Port Elizabeth -- Finance
- Description: South Africa, recognised as a developing economy, is encouraging its citizens to be entrepreneurs through various initiatives and assistance, with a bias towards the previously disadvantage people. This encouragement, from the government, has been taken advantage of by numerous citizens to the detriment of themselves, especially in the transport industry. Kazderich Pro Trans, a small transport entrepreneur, has founded itself based on the notion that businesses will utilize its services frequently based on the preferential treatment, to previously disadvantaged communities. The stakeholders in the transport industry, however is firstly geared towards maintaining their market share in a fiercely competitive industry with arguably an introspective view of the preferential treatment governmental policies. The purpose of this is to research the transport industry and accurately identify the environment the transport businesses operate in, with a view of analysing competencies that attract and retain business. This paper negates the government policy to a minor external environmental factor and argues that the company (Kazderich Pro Trans) should operate on the same principals as its competitors in the transport industry. The important issue being discussed in this research, the long term strategy, is to make small transport entrepreneurs realise that researching and planning their business are more important than starting it. The attraction and retention of clients is the basis of a successful transport business and the analyses of the questionnaire employed are used as guidance in developing the long term strategy.
- Full Text:
- Date Issued: 2008
- Authors: Burgins, David Christopher
- Date: 2008
- Subjects: Transportation -- South Africa -- Port Elizabeth -- Planning , Transportation and state -- South Africa -- Port Elizabeth , Transportation -- South Africa -- Port Elizabeth -- Finance
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8714 , http://hdl.handle.net/10948/929 , Transportation -- South Africa -- Port Elizabeth -- Planning , Transportation and state -- South Africa -- Port Elizabeth , Transportation -- South Africa -- Port Elizabeth -- Finance
- Description: South Africa, recognised as a developing economy, is encouraging its citizens to be entrepreneurs through various initiatives and assistance, with a bias towards the previously disadvantage people. This encouragement, from the government, has been taken advantage of by numerous citizens to the detriment of themselves, especially in the transport industry. Kazderich Pro Trans, a small transport entrepreneur, has founded itself based on the notion that businesses will utilize its services frequently based on the preferential treatment, to previously disadvantaged communities. The stakeholders in the transport industry, however is firstly geared towards maintaining their market share in a fiercely competitive industry with arguably an introspective view of the preferential treatment governmental policies. The purpose of this is to research the transport industry and accurately identify the environment the transport businesses operate in, with a view of analysing competencies that attract and retain business. This paper negates the government policy to a minor external environmental factor and argues that the company (Kazderich Pro Trans) should operate on the same principals as its competitors in the transport industry. The important issue being discussed in this research, the long term strategy, is to make small transport entrepreneurs realise that researching and planning their business are more important than starting it. The attraction and retention of clients is the basis of a successful transport business and the analyses of the questionnaire employed are used as guidance in developing the long term strategy.
- Full Text:
- Date Issued: 2008
Development of a novel in situ CPRG-based biosensor and bioprobe for monitoring coliform β-D-Galactosidase in water polluted by faecal matter
- Authors: Wutor, Victor Collins
- Date: 2008
- Subjects: Biosensors Molecular probes Enterobacteriaceae Feces -- Microbiology Water -- Pollution -- Environmental aspects Environmental monitoring Chromogenic compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3944 , http://hdl.handle.net/10962/d1004003
- Description: The ultimate objective of this work was to develop a real-time method for detecting and monitoring β-D-galactosidase as a suitable indicator of the potential presence of total coliform bacteria in water environments. Preliminary comparison of the chromogenic substrate, chlorophenol red β-D-galactopyranoside and the fluorogenic substrate, MuGAL, revealed unreliable results with the fluorogenic technique due to interference from compounds commonly found in environmental water samples. Thus, the chromogenic assay was further explored. Hydrolysis of the chromogenic substrate chlorophenol red β-D-galactopyranoside by β-D-galactosidase to yield chlorophenol red was the basis of this assay. Fundamental studies with chlorophenol red β-Dgalactopyranoside showed that β-D-galactosidase occurs extracellularly and in low concentrations in the polluted water environment. A direct correlation between enzyme activity and an increase in environmental water sample volume, as well as enzyme activity with total coliform colony forming unit counts were observed. Spectrophotometric detection was achieved within a maximum period of 24 h with a limit of detection level of 1 colony forming unit 100 ml[superscript -1]. This enzyme also exhibited physical and kinetic properties different from those of the pure commercially available β-D-galactosidase. Cell permeabilisation was not required for releasing enzymes into the extracellular environment. PEG 20 000 offered the best option for concentrating β-D-galactosidase. The source of β-D-galactosidase in the polluted environmental water samples was confirmed as Escherichia coli through SDS-PAGE, tryptic mapping and MALDI-TOF, thus justifying the further use of this method for detecting and/or monitoring total coliforms. Several compounds and metal ions commonly found in environmental water samples (as well as those used in water treatment processes) did have an effect on β-D-galactosidase. All the divalent cations except Mg [superscript 2+], at the concentrations studied, inhibited the relative activity of β-D-galactosidase in both commercial β-D-galactosidase and environmental samples. Immobilisation of chlorophenol red β-D-galactopyranoside onto a solid support material for the development of a strip bioprobe was unsuccessful, even though the nylon support material yielded some positive results. A monthly (seasonal) variation in β-Dgalactosidase activity from the environmental water samples was observed, with the highest activity coinciding with the highest monthly temperatures. Electro-oxidative detection and/or monitoring of chlorophenol red was possible. Chlorophenol red detection was linear over a wide range of concentrations (0.001-0.01 μg ml[superscript -1]). Interference by chlorophenol red β-D-galactopyranoside in the reduction window affected analysis. A range of phthalocyanine metal complexes were studied in an attempt to reduce fouling and/or increase the sensitivity of the biosensor. The selected phthalocyanine metal complexes were generally sensitive to changes in pH with a reduction in sensitivity from acidic pH to alkaline pH. The tetrasulphonated phthalocyanine metal complex of copper was, however, more stable with a minimum change of sensitivity. The phthalocyanine metal complexes were generally stable to changes in temperature. While only two consecutive scans were possible with the unmodified glassy carbon electrode, 77 consecutive scans were performed successfully with the CuPc-modified glassy carbon electrode. Among the phthalocyanine metal complexes studied, the CuPc-modified glassy carbon electrode therefore provided excellent results for the development of a biosensor. The CuPc modified-glassy carbon electrode detected 1 colony forming unit 100 ml[superscript -1] in 15 minutes, while the plain unmodified glassy carbon electrode required 6 hours to detect the equivalent number of colony forming units. CoPc, ZnPc and CuTSPc required 2, 2.25 and 1.75 h, respectively, to detect the same numbers of colony forming units. The CuPcmodified glassy carbon electrode detected 40 colony forming units 100 ml[superscript -1] instantly. In general, a direct correlation between colony forming units and current generated in the sensor was observed (R2=0.92). A higher correlation coefficient of 0.99 for 0-30 coliform colony forming units 100 ml[superscript -1] was determined. Current was detected in some water samples which did not show any colony forming units on the media, probably due to the phenomenon of viable but non-culturable bacteria, which is the major disadvantage encountered in the use of media for detecting indicator microorganisms. This novel biosensor therefore presents a very robust and sensitive technique for the detection and/or monitoring of coliform bacterial activity in water.
- Full Text:
- Date Issued: 2008
- Authors: Wutor, Victor Collins
- Date: 2008
- Subjects: Biosensors Molecular probes Enterobacteriaceae Feces -- Microbiology Water -- Pollution -- Environmental aspects Environmental monitoring Chromogenic compounds
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3944 , http://hdl.handle.net/10962/d1004003
- Description: The ultimate objective of this work was to develop a real-time method for detecting and monitoring β-D-galactosidase as a suitable indicator of the potential presence of total coliform bacteria in water environments. Preliminary comparison of the chromogenic substrate, chlorophenol red β-D-galactopyranoside and the fluorogenic substrate, MuGAL, revealed unreliable results with the fluorogenic technique due to interference from compounds commonly found in environmental water samples. Thus, the chromogenic assay was further explored. Hydrolysis of the chromogenic substrate chlorophenol red β-D-galactopyranoside by β-D-galactosidase to yield chlorophenol red was the basis of this assay. Fundamental studies with chlorophenol red β-Dgalactopyranoside showed that β-D-galactosidase occurs extracellularly and in low concentrations in the polluted water environment. A direct correlation between enzyme activity and an increase in environmental water sample volume, as well as enzyme activity with total coliform colony forming unit counts were observed. Spectrophotometric detection was achieved within a maximum period of 24 h with a limit of detection level of 1 colony forming unit 100 ml[superscript -1]. This enzyme also exhibited physical and kinetic properties different from those of the pure commercially available β-D-galactosidase. Cell permeabilisation was not required for releasing enzymes into the extracellular environment. PEG 20 000 offered the best option for concentrating β-D-galactosidase. The source of β-D-galactosidase in the polluted environmental water samples was confirmed as Escherichia coli through SDS-PAGE, tryptic mapping and MALDI-TOF, thus justifying the further use of this method for detecting and/or monitoring total coliforms. Several compounds and metal ions commonly found in environmental water samples (as well as those used in water treatment processes) did have an effect on β-D-galactosidase. All the divalent cations except Mg [superscript 2+], at the concentrations studied, inhibited the relative activity of β-D-galactosidase in both commercial β-D-galactosidase and environmental samples. Immobilisation of chlorophenol red β-D-galactopyranoside onto a solid support material for the development of a strip bioprobe was unsuccessful, even though the nylon support material yielded some positive results. A monthly (seasonal) variation in β-Dgalactosidase activity from the environmental water samples was observed, with the highest activity coinciding with the highest monthly temperatures. Electro-oxidative detection and/or monitoring of chlorophenol red was possible. Chlorophenol red detection was linear over a wide range of concentrations (0.001-0.01 μg ml[superscript -1]). Interference by chlorophenol red β-D-galactopyranoside in the reduction window affected analysis. A range of phthalocyanine metal complexes were studied in an attempt to reduce fouling and/or increase the sensitivity of the biosensor. The selected phthalocyanine metal complexes were generally sensitive to changes in pH with a reduction in sensitivity from acidic pH to alkaline pH. The tetrasulphonated phthalocyanine metal complex of copper was, however, more stable with a minimum change of sensitivity. The phthalocyanine metal complexes were generally stable to changes in temperature. While only two consecutive scans were possible with the unmodified glassy carbon electrode, 77 consecutive scans were performed successfully with the CuPc-modified glassy carbon electrode. Among the phthalocyanine metal complexes studied, the CuPc-modified glassy carbon electrode therefore provided excellent results for the development of a biosensor. The CuPc modified-glassy carbon electrode detected 1 colony forming unit 100 ml[superscript -1] in 15 minutes, while the plain unmodified glassy carbon electrode required 6 hours to detect the equivalent number of colony forming units. CoPc, ZnPc and CuTSPc required 2, 2.25 and 1.75 h, respectively, to detect the same numbers of colony forming units. The CuPcmodified glassy carbon electrode detected 40 colony forming units 100 ml[superscript -1] instantly. In general, a direct correlation between colony forming units and current generated in the sensor was observed (R2=0.92). A higher correlation coefficient of 0.99 for 0-30 coliform colony forming units 100 ml[superscript -1] was determined. Current was detected in some water samples which did not show any colony forming units on the media, probably due to the phenomenon of viable but non-culturable bacteria, which is the major disadvantage encountered in the use of media for detecting indicator microorganisms. This novel biosensor therefore presents a very robust and sensitive technique for the detection and/or monitoring of coliform bacterial activity in water.
- Full Text:
- Date Issued: 2008
Development of a reciprocating aerofoil wind energy harvester
- Authors: Phillips, Russell Leslie
- Date: 2008
- Subjects: Windmills , Wind power , Wind turbines
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9622 , http://hdl.handle.net/10948/899 , Windmills , Wind power , Wind turbines
- Description: Cross flow wind turbines are not unique. The performance of Savonius and Darrieus turbines is well documented. Both share the advantage of being able to accept fluid flow from any direction. The Savonius is drag based and hence has poor power output while the Darrieus is lift based. Due to the fact that the Darrieus has fixed blades the fluid flow through the rotor does not result in optimal lift being generated at all points in the rotation circle. A drawback of the Darrieus system is that it has to operate at a high tip-to wind-speed ratio to obtain reasonable performance with the fixed blades. Deviation from a small optimal range of tip speed ratios results in poor performance. The Darrieus also has poor starting torque. The research conducted in this project focused on overcoming the shortcomings of other turbines and developing an effective cross flow turbine capable of good performance. A number of different concepts were experimented with, however all were based on a symmetrical aerofoil presented to the actual relative airflow at an angle that would produce the highest lift force at all times. The lift force was then utilized to generate movement and to do work on an electrical generator. All concepts contemplated were researched to ascertain their appropriateness for the intended application. During development of the final experimental platform and after lodging of a provisional patent (RSA 2007/00927) it was ascertained that the design shared some similarities with an American patent 5503525 dated 28/4/1994. This patent employed complex electronic sensing and control equipment for control of blade angle. This was thought to be overly complex and costly, particularly for small scale wind energy generation applications and a simpler mechanical solution was sought in the design of the final experimental platform used in this project. The design of the mechanical control system was refined in an attempt to make it simpler, more durable and employ the least number of moving parts. Literature studies and patent searches conducted, suggested that the mechanical control system as developed for the final experimental platform was unique. The enormous variation in the power available from the wind at the different wind speeds likely to be encountered by the device necessitated some means of control. In high wind conditions control of the amount of wind power into the device was deemed to be the preferable means of control. A number of different concepts to achieve this were devised and tested. The final concept employed limited the tail angle deflection and hence the lift produced by the aerofoils. This resulted in a seamless “throttle” control allowing the device to be used in any wind strength by adjusting the control to a position that resulted in the device receiving a suitable amount of power from the wind. The outcome of performance tests conducted indicated that the device has the potential to be developed into a viable wind turbine for both small and large scale applications. The ability to control the power input from the wind to the machine from zero to a maximum is considered to be one of the most beneficial outcomes of this project and together with the quiet operation and low speed, are considered the main advantages of the device over existing wind turbine designs. The possibilities of using the device to compress air for energy storage are exciting avenues that warrant further research.
- Full Text:
- Date Issued: 2008
- Authors: Phillips, Russell Leslie
- Date: 2008
- Subjects: Windmills , Wind power , Wind turbines
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: vital:9622 , http://hdl.handle.net/10948/899 , Windmills , Wind power , Wind turbines
- Description: Cross flow wind turbines are not unique. The performance of Savonius and Darrieus turbines is well documented. Both share the advantage of being able to accept fluid flow from any direction. The Savonius is drag based and hence has poor power output while the Darrieus is lift based. Due to the fact that the Darrieus has fixed blades the fluid flow through the rotor does not result in optimal lift being generated at all points in the rotation circle. A drawback of the Darrieus system is that it has to operate at a high tip-to wind-speed ratio to obtain reasonable performance with the fixed blades. Deviation from a small optimal range of tip speed ratios results in poor performance. The Darrieus also has poor starting torque. The research conducted in this project focused on overcoming the shortcomings of other turbines and developing an effective cross flow turbine capable of good performance. A number of different concepts were experimented with, however all were based on a symmetrical aerofoil presented to the actual relative airflow at an angle that would produce the highest lift force at all times. The lift force was then utilized to generate movement and to do work on an electrical generator. All concepts contemplated were researched to ascertain their appropriateness for the intended application. During development of the final experimental platform and after lodging of a provisional patent (RSA 2007/00927) it was ascertained that the design shared some similarities with an American patent 5503525 dated 28/4/1994. This patent employed complex electronic sensing and control equipment for control of blade angle. This was thought to be overly complex and costly, particularly for small scale wind energy generation applications and a simpler mechanical solution was sought in the design of the final experimental platform used in this project. The design of the mechanical control system was refined in an attempt to make it simpler, more durable and employ the least number of moving parts. Literature studies and patent searches conducted, suggested that the mechanical control system as developed for the final experimental platform was unique. The enormous variation in the power available from the wind at the different wind speeds likely to be encountered by the device necessitated some means of control. In high wind conditions control of the amount of wind power into the device was deemed to be the preferable means of control. A number of different concepts to achieve this were devised and tested. The final concept employed limited the tail angle deflection and hence the lift produced by the aerofoils. This resulted in a seamless “throttle” control allowing the device to be used in any wind strength by adjusting the control to a position that resulted in the device receiving a suitable amount of power from the wind. The outcome of performance tests conducted indicated that the device has the potential to be developed into a viable wind turbine for both small and large scale applications. The ability to control the power input from the wind to the machine from zero to a maximum is considered to be one of the most beneficial outcomes of this project and together with the quiet operation and low speed, are considered the main advantages of the device over existing wind turbine designs. The possibilities of using the device to compress air for energy storage are exciting avenues that warrant further research.
- Full Text:
- Date Issued: 2008
Development of an integration model for the transport operators in the Nelson Mandela Bay area
- Authors: Pienaar, Jacques Ludolph
- Date: 2008
- Subjects: Urban transportation -- South Africa -- Port Elizabeth , Transportation -- South Africa -- Port Elizabeth -- Planning
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8722 , http://hdl.handle.net/10948/900 , Urban transportation -- South Africa -- Port Elizabeth , Transportation -- South Africa -- Port Elizabeth -- Planning
- Description: This research paper focuses on developing a model for the integration of the transport operators in the Nelson Mandela Bay area. The motivation for this integration is the Nelson Mandela Bay Municipality’s Public Transport Plan, which has set the goal of developing a new public transport system for the Metropolitan area. This system will integrate the different modes of transport into a single, seamless and scheduled service which will adhere to contractually enforced levels of quality, reliability and safety. In order to achieve this vision, the current bus and taxi operators will need to be unified into a viable and operational entity structure which will provide the required services to the public. The main research problem has therefore been identified as follows: How can the bus and taxi operators in Nelson Mandela Bay be integrated into a single entity, or small number of entities, in order to provide a viable, efficient and sustainable public transport service? This research paper sought to address this problem by conducting a case study of the Nelson Mandela Bay project, which took place over the course of a one year period. The author served as the project manager on the team that was responsible for developing the integration model. Additional research included a study visit to the cities of Bogota and Pereira in Colombia, which have implemented similar transport models, as well as a secondary study focusing on generic organisational integration strategies in existing literature. This paper is fundamentally a qualitative study. In this light, the research data was analysed according to the quasi-judicial method, which was deemed most suitable to the case study format adopted. The findings of the analysis were evaluated, and based on the resultant conclusions, a final integration model was recommended. The fact that this study is based on an actual project that has real world implications and consequences makes the result very relevant, and as such it will serve as a valuable addition to the body of knowledge which can be of assistance to other cities or project teams facing similar challenges in South Africa or even internationally.
- Full Text:
- Date Issued: 2008
- Authors: Pienaar, Jacques Ludolph
- Date: 2008
- Subjects: Urban transportation -- South Africa -- Port Elizabeth , Transportation -- South Africa -- Port Elizabeth -- Planning
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8722 , http://hdl.handle.net/10948/900 , Urban transportation -- South Africa -- Port Elizabeth , Transportation -- South Africa -- Port Elizabeth -- Planning
- Description: This research paper focuses on developing a model for the integration of the transport operators in the Nelson Mandela Bay area. The motivation for this integration is the Nelson Mandela Bay Municipality’s Public Transport Plan, which has set the goal of developing a new public transport system for the Metropolitan area. This system will integrate the different modes of transport into a single, seamless and scheduled service which will adhere to contractually enforced levels of quality, reliability and safety. In order to achieve this vision, the current bus and taxi operators will need to be unified into a viable and operational entity structure which will provide the required services to the public. The main research problem has therefore been identified as follows: How can the bus and taxi operators in Nelson Mandela Bay be integrated into a single entity, or small number of entities, in order to provide a viable, efficient and sustainable public transport service? This research paper sought to address this problem by conducting a case study of the Nelson Mandela Bay project, which took place over the course of a one year period. The author served as the project manager on the team that was responsible for developing the integration model. Additional research included a study visit to the cities of Bogota and Pereira in Colombia, which have implemented similar transport models, as well as a secondary study focusing on generic organisational integration strategies in existing literature. This paper is fundamentally a qualitative study. In this light, the research data was analysed according to the quasi-judicial method, which was deemed most suitable to the case study format adopted. The findings of the analysis were evaluated, and based on the resultant conclusions, a final integration model was recommended. The fact that this study is based on an actual project that has real world implications and consequences makes the result very relevant, and as such it will serve as a valuable addition to the body of knowledge which can be of assistance to other cities or project teams facing similar challenges in South Africa or even internationally.
- Full Text:
- Date Issued: 2008
Development of methodologies for deploying and implementing local & medium area broadband PLC networks in office and residential electric grids
- Authors: Tinarwo, Loyd
- Date: 2008
- Subjects: Broadband communication systems , Power transmission , Telecommunication lines
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11375 , http://hdl.handle.net/10353/83 , Broadband communication systems , Power transmission , Telecommunication lines
- Description: The use of electrical networks for telecommunications has a long history. It has been known since the beginning of the twentieth century [Ahola03]. The idea of using electrical networks for broadband communications arose in the 1990s [Hrasnica et al 04]. Recent and growing research interest has indicated that PowerLine Communications (PLC) is the threshold for achieving broadband delivery particularly in very dispersed and low teledensity areas. Currently, there are numerous PLC trials and commercial deployments underway inside and outside South Africa. Nevertheless, these PLC deployments are very isolated, done without clear methodology and performance remains bound to the physical layout of the electrical network. Because of that high bandwidth broadband PLC systems are prone to poor performance and this in turn limits the acceptance and deployment of this emerging alternative broadband technology. Though, PLC technical challenges are being addressed, there has been little analysis and research work that is focused on the “Development of Methodologies for Deploying and Implementing Local & Medium Area Broadband Power Line in Residential and Office Electric Grids” that would lead to broadband PLC being adopted and be of greater use to non-broadband communities of South Africa. PLC is a term describing several different systems using electrical grid distribution wires for simultaneous distribution of data by superimposing an analog signal [Hrasnica et al 04]. The research proposed and presented broadband PLC methodologies for typical medium voltage and local voltage PLC networks. These methodologieswere implemented and experimented with in configurations which closely mirrored residential and office settings through laboratory and multibuilding experiments using commercial 2nd Generation Mitsubishi Electric PLC technology. Research results presented not only serve to provide insight into broadband PLC but also how it handled broadband applications (communications), competed and compared with other technologies such as Ethernet LAN. In combination with networking communication theories, the research explored and analyzed the extent of PLC in providing broadband communication to residential and office electric grids at the University Fort Hare, Computer Science Department.
- Full Text:
- Date Issued: 2008
- Authors: Tinarwo, Loyd
- Date: 2008
- Subjects: Broadband communication systems , Power transmission , Telecommunication lines
- Language: English
- Type: Thesis , Masters , MSc (Computer Science)
- Identifier: vital:11375 , http://hdl.handle.net/10353/83 , Broadband communication systems , Power transmission , Telecommunication lines
- Description: The use of electrical networks for telecommunications has a long history. It has been known since the beginning of the twentieth century [Ahola03]. The idea of using electrical networks for broadband communications arose in the 1990s [Hrasnica et al 04]. Recent and growing research interest has indicated that PowerLine Communications (PLC) is the threshold for achieving broadband delivery particularly in very dispersed and low teledensity areas. Currently, there are numerous PLC trials and commercial deployments underway inside and outside South Africa. Nevertheless, these PLC deployments are very isolated, done without clear methodology and performance remains bound to the physical layout of the electrical network. Because of that high bandwidth broadband PLC systems are prone to poor performance and this in turn limits the acceptance and deployment of this emerging alternative broadband technology. Though, PLC technical challenges are being addressed, there has been little analysis and research work that is focused on the “Development of Methodologies for Deploying and Implementing Local & Medium Area Broadband Power Line in Residential and Office Electric Grids” that would lead to broadband PLC being adopted and be of greater use to non-broadband communities of South Africa. PLC is a term describing several different systems using electrical grid distribution wires for simultaneous distribution of data by superimposing an analog signal [Hrasnica et al 04]. The research proposed and presented broadband PLC methodologies for typical medium voltage and local voltage PLC networks. These methodologieswere implemented and experimented with in configurations which closely mirrored residential and office settings through laboratory and multibuilding experiments using commercial 2nd Generation Mitsubishi Electric PLC technology. Research results presented not only serve to provide insight into broadband PLC but also how it handled broadband applications (communications), competed and compared with other technologies such as Ethernet LAN. In combination with networking communication theories, the research explored and analyzed the extent of PLC in providing broadband communication to residential and office electric grids at the University Fort Hare, Computer Science Department.
- Full Text:
- Date Issued: 2008
Development of platinum metal specific separating agents
- Authors: Jonck, Heine
- Date: 2008
- Subjects: Platinum , Platinum -- Separation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10401 , http://hdl.handle.net/10948/712 , Platinum , Platinum -- Separation
- Description: In this dissertation, the aim was to develop a platinum specific resin to be utilized for the early removal of platinum from the industrial feed solution. Efforts were therefore directed towards the syntheses of silica based resins, with active centra, designed for platinum. The large chlorometallate ions present in the feed stream, were characterized in terms of physical parameters relevant to phase distribution, namely distortability (RD), charge density, softness (σ) etc. Matching cations for each of the types were investigated. In order to attempt the design of platinum specific resins, different structural amines were used to aminate the silicone precursor and to subsequently fix these onto the silica framework. Two different solvents namely alcohol and dmf were used in this process, resulting in two sets of resins, with different properties. The design was based on previous experience with these ions, with reference to their behaviour towards different types of cations. The platinum species, PtCl6 2- and PtCl4 2-, as well as the most important contaminants in the feed stream, were typified, bearing in mind size, charge, charge density and distortability. Different types of cationic centra, having differences in charge density, stereochemical crowding and extent of hydrophobicity, were synthesized and tested-both as solvent extractants (where possible) and silica based resins. The results indicated that, partly screened secondary ammonium cationic resin species, which could be regarded as “intermediate”, proved to be satisfactory both in their high percentage extraction for PtCl4 2- and rejection of contaminants like chlororhodates, chloroiridates(III) and FeCl4 -. It was however necessary, to work at a redox potential, where iridium(IV) in the form of IrCl6 2-, was absent. Various 2-aminoalkane resins were prepared, with variation in the length of alkane group and synthesised by the two different solvents. The latter resulted in two sets of resins with not only differing compactness, but also having significantly different properties with reference to platinum specificity, HCl effect and stripping potential. The 2-aminobutane and 2-aminoheptane resins in particular, proved to be very satisfactory platinum specific resins, both with respect to selectivity, platinum capacity and stripping potential. The various physical parameters could be applied to identify the chemical behaviour of anions and assist in the development of anion specificity for the relevant species.
- Full Text:
- Date Issued: 2008
- Authors: Jonck, Heine
- Date: 2008
- Subjects: Platinum , Platinum -- Separation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10401 , http://hdl.handle.net/10948/712 , Platinum , Platinum -- Separation
- Description: In this dissertation, the aim was to develop a platinum specific resin to be utilized for the early removal of platinum from the industrial feed solution. Efforts were therefore directed towards the syntheses of silica based resins, with active centra, designed for platinum. The large chlorometallate ions present in the feed stream, were characterized in terms of physical parameters relevant to phase distribution, namely distortability (RD), charge density, softness (σ) etc. Matching cations for each of the types were investigated. In order to attempt the design of platinum specific resins, different structural amines were used to aminate the silicone precursor and to subsequently fix these onto the silica framework. Two different solvents namely alcohol and dmf were used in this process, resulting in two sets of resins, with different properties. The design was based on previous experience with these ions, with reference to their behaviour towards different types of cations. The platinum species, PtCl6 2- and PtCl4 2-, as well as the most important contaminants in the feed stream, were typified, bearing in mind size, charge, charge density and distortability. Different types of cationic centra, having differences in charge density, stereochemical crowding and extent of hydrophobicity, were synthesized and tested-both as solvent extractants (where possible) and silica based resins. The results indicated that, partly screened secondary ammonium cationic resin species, which could be regarded as “intermediate”, proved to be satisfactory both in their high percentage extraction for PtCl4 2- and rejection of contaminants like chlororhodates, chloroiridates(III) and FeCl4 -. It was however necessary, to work at a redox potential, where iridium(IV) in the form of IrCl6 2-, was absent. Various 2-aminoalkane resins were prepared, with variation in the length of alkane group and synthesised by the two different solvents. The latter resulted in two sets of resins with not only differing compactness, but also having significantly different properties with reference to platinum specificity, HCl effect and stripping potential. The 2-aminobutane and 2-aminoheptane resins in particular, proved to be very satisfactory platinum specific resins, both with respect to selectivity, platinum capacity and stripping potential. The various physical parameters could be applied to identify the chemical behaviour of anions and assist in the development of anion specificity for the relevant species.
- Full Text:
- Date Issued: 2008
Die liturgiese gebruik van die orrel in 'n post-mordene era: persepsies van kerkmusici en leraars van die Nederduitse Gereformeerde gemeentes in Port Elizabeth
- Authors: Heunis, Sulani
- Date: 2008
- Subjects: Organ music -- South Africa -- Port Elizabeth , Chorale preludes
- Language: Afrikaans
- Type: Thesis , Masters , MMus
- Identifier: vital:8511 , http://hdl.handle.net/10948/787 , Organ music -- South Africa -- Port Elizabeth , Chorale preludes
- Description: In this study the liturgical usage of the organ is investigated within a post-modern society. It focuses specifically on the church services of the Dutch Reformed Congregations of Port Elizabeth with regards to the functionality of the organ during morning and evening services. The objectives of the study are to demonstrate the current situation of musical worship in the Dutch Reformed Congregations of Port Elizabeth. Furthermore it serves as a way to indicate any deficiency in the field, which would need to be addressed. In order to achieve these objectives, both a qualitative and quantitative study is undertaken. The qualitative study investigates existing literature regarding the church service and its music. The quantitative study comprises an analysis of self-administered questionnaires that was handed over for completion by the Dutch Reformed Congregations of Port Elizabeth. The results obtained were electronically processed to percentages and graphic illustrations. In this mini-treatise it is argued that the usage of other music instruments (in the form of music worship groups) during church services could possibly lead to a change in the liturgical function of the organ. It was found that the usage of the organ in the Dutch Reformed Congregations of Port Elizabeth was mainly retained during morning services. During evening services however, the usage of other music instruments was in the majority, which resulted in a decrease of organ usage. It was further discovered that a large group of organists are not involved with music worship groups. Training of organists in a contemporary style of music worship will therefore serve as a significant purpose to fulfil this deficiency.
- Full Text:
- Date Issued: 2008
- Authors: Heunis, Sulani
- Date: 2008
- Subjects: Organ music -- South Africa -- Port Elizabeth , Chorale preludes
- Language: Afrikaans
- Type: Thesis , Masters , MMus
- Identifier: vital:8511 , http://hdl.handle.net/10948/787 , Organ music -- South Africa -- Port Elizabeth , Chorale preludes
- Description: In this study the liturgical usage of the organ is investigated within a post-modern society. It focuses specifically on the church services of the Dutch Reformed Congregations of Port Elizabeth with regards to the functionality of the organ during morning and evening services. The objectives of the study are to demonstrate the current situation of musical worship in the Dutch Reformed Congregations of Port Elizabeth. Furthermore it serves as a way to indicate any deficiency in the field, which would need to be addressed. In order to achieve these objectives, both a qualitative and quantitative study is undertaken. The qualitative study investigates existing literature regarding the church service and its music. The quantitative study comprises an analysis of self-administered questionnaires that was handed over for completion by the Dutch Reformed Congregations of Port Elizabeth. The results obtained were electronically processed to percentages and graphic illustrations. In this mini-treatise it is argued that the usage of other music instruments (in the form of music worship groups) during church services could possibly lead to a change in the liturgical function of the organ. It was found that the usage of the organ in the Dutch Reformed Congregations of Port Elizabeth was mainly retained during morning services. During evening services however, the usage of other music instruments was in the majority, which resulted in a decrease of organ usage. It was further discovered that a large group of organists are not involved with music worship groups. Training of organists in a contemporary style of music worship will therefore serve as a significant purpose to fulfil this deficiency.
- Full Text:
- Date Issued: 2008
Diet and feeding effects of introduced giraffe in the Eastern Cape
- Authors: Jacobs, Evert Philippus
- Date: 2008
- Subjects: Giraffe -- Food -- South Africa -- Eastern Cape , Giraffe -- Ecology -- South Africa -- Eastern Cape , Animal-plant relationships -- South Africa -- Eastern Cape , Introduced mammals -- Ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10703 , http://hdl.handle.net/10948/964 , Giraffe -- Food -- South Africa -- Eastern Cape , Giraffe -- Ecology -- South Africa -- Eastern Cape , Animal-plant relationships -- South Africa -- Eastern Cape , Introduced mammals -- Ecology -- South Africa -- Eastern Cape
- Description: This study presents the results of a study on introduced giraffe diet and feeding effects within the Eastern Cape Province of South Africa. Five sites were selected over a moisture gradient from the mesic east to the arid west of the Eastern Cape to describe giraffe diet and provide baseline data for feeding effect experiments. At each site faecal samples were collected seasonally and diet composition determined by microhistological analysis. Plant species availability was measured using the point intersect method in order to compare plant availability to plant consumption to determine diet preferences. Giraffe diet across the sites showed a unimodal response to rainfall by utilising fewer species in drier areas where plant availability is low and increasing the number of species consumed as the rainfall increases. In higher rainfall areas, giraffe reduced the number of plant species fed upon because of the high availability of important species that reduces the need for a varied diet. Across all sites, plant availability was dominated by woody plant species (more than 90 percent at each site). A total of 57 plants species were recorded as being eaten across the five sites. Several PDI (Principle Diet Items) plant species (Acacia karroo, Schotia afra, Pappea capensis and Euclea undulata) were eaten across sites. Over all the sites, significantly preferred species were Asparagus striatus, Schotia latifolia, Asparagus suaveolens, Commelina benghalensis, Viscum rotundifolium, and Acacia cyclops. Acacia karroo, Schotia afra, Pappea capensis, Rhus crenata, A. tetracantha, and Grewia robusta were utilised in proportion to their availability. Euclea undulata, Rhus longispina and Putterlickia pyracantha were avoided. Feeding effects were tested by erecting exclosures around trees, covering one half of each tree. Ten trees were selected for these manipulative experiments which ran from September 2003 to February 2005. The number of branches, number of leaves, branch orders, branch diameter, branch length, leaf length and leaf width were measured for ten samples per side (enclosed vs. exposed) and analysed using a Wilcoxon matched pairs test and tested for effect size using Cohen’s d. Although no significant differences were detected between the sides measured, the effect size indicated differences in all measurements between sides ranging from low to moderate. Leaf length was greater on the outside of exclosures and showed a moderate difference between the sides in terms of the d-value with the p-value (0.059) tending towards significance. Although leaf width was higher on the inside of exclosures, it only showed a moderate difference for d with no statistical significance. Leaf area was higher on the inside of exclosures and tended to significance (p = 0.059) and similarly the d value indicated moderate differences between the sides in terms of effect size. Similarly branch length was higher on the inside of exclosures although not significantly, the p-value (0.07) approached significance. The effect size for branch length also showed a moderate difference between the sides. The number of branches and the number of leaves showed no statistical differences between the sides although the p-value (0.059) for the number of branches, as well as number of leaves (p = 0.07) approached significance. For both these variables, effect size showed a moderate difference. Giraffe showed diversity in their diet selection across sites but mainly fed upon available species. Some preferred species were however less available and this preference could possibly result in increased pressure on the selected plant species Exclosure experiments showed no significant differences in leaf and shoot characteristics although all measurements showed differences in terms of effect size meriting further investigation. It is concluded that giraffe impact on sites may be reduced if populations are properly managed however, high densities of giraffe could lead to similar vegetation impacts as observed in other areas where giraffe have been introduced and potentially change vegetation structure and plant community composition.
- Full Text:
- Date Issued: 2008
- Authors: Jacobs, Evert Philippus
- Date: 2008
- Subjects: Giraffe -- Food -- South Africa -- Eastern Cape , Giraffe -- Ecology -- South Africa -- Eastern Cape , Animal-plant relationships -- South Africa -- Eastern Cape , Introduced mammals -- Ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:10703 , http://hdl.handle.net/10948/964 , Giraffe -- Food -- South Africa -- Eastern Cape , Giraffe -- Ecology -- South Africa -- Eastern Cape , Animal-plant relationships -- South Africa -- Eastern Cape , Introduced mammals -- Ecology -- South Africa -- Eastern Cape
- Description: This study presents the results of a study on introduced giraffe diet and feeding effects within the Eastern Cape Province of South Africa. Five sites were selected over a moisture gradient from the mesic east to the arid west of the Eastern Cape to describe giraffe diet and provide baseline data for feeding effect experiments. At each site faecal samples were collected seasonally and diet composition determined by microhistological analysis. Plant species availability was measured using the point intersect method in order to compare plant availability to plant consumption to determine diet preferences. Giraffe diet across the sites showed a unimodal response to rainfall by utilising fewer species in drier areas where plant availability is low and increasing the number of species consumed as the rainfall increases. In higher rainfall areas, giraffe reduced the number of plant species fed upon because of the high availability of important species that reduces the need for a varied diet. Across all sites, plant availability was dominated by woody plant species (more than 90 percent at each site). A total of 57 plants species were recorded as being eaten across the five sites. Several PDI (Principle Diet Items) plant species (Acacia karroo, Schotia afra, Pappea capensis and Euclea undulata) were eaten across sites. Over all the sites, significantly preferred species were Asparagus striatus, Schotia latifolia, Asparagus suaveolens, Commelina benghalensis, Viscum rotundifolium, and Acacia cyclops. Acacia karroo, Schotia afra, Pappea capensis, Rhus crenata, A. tetracantha, and Grewia robusta were utilised in proportion to their availability. Euclea undulata, Rhus longispina and Putterlickia pyracantha were avoided. Feeding effects were tested by erecting exclosures around trees, covering one half of each tree. Ten trees were selected for these manipulative experiments which ran from September 2003 to February 2005. The number of branches, number of leaves, branch orders, branch diameter, branch length, leaf length and leaf width were measured for ten samples per side (enclosed vs. exposed) and analysed using a Wilcoxon matched pairs test and tested for effect size using Cohen’s d. Although no significant differences were detected between the sides measured, the effect size indicated differences in all measurements between sides ranging from low to moderate. Leaf length was greater on the outside of exclosures and showed a moderate difference between the sides in terms of the d-value with the p-value (0.059) tending towards significance. Although leaf width was higher on the inside of exclosures, it only showed a moderate difference for d with no statistical significance. Leaf area was higher on the inside of exclosures and tended to significance (p = 0.059) and similarly the d value indicated moderate differences between the sides in terms of effect size. Similarly branch length was higher on the inside of exclosures although not significantly, the p-value (0.07) approached significance. The effect size for branch length also showed a moderate difference between the sides. The number of branches and the number of leaves showed no statistical differences between the sides although the p-value (0.059) for the number of branches, as well as number of leaves (p = 0.07) approached significance. For both these variables, effect size showed a moderate difference. Giraffe showed diversity in their diet selection across sites but mainly fed upon available species. Some preferred species were however less available and this preference could possibly result in increased pressure on the selected plant species Exclosure experiments showed no significant differences in leaf and shoot characteristics although all measurements showed differences in terms of effect size meriting further investigation. It is concluded that giraffe impact on sites may be reduced if populations are properly managed however, high densities of giraffe could lead to similar vegetation impacts as observed in other areas where giraffe have been introduced and potentially change vegetation structure and plant community composition.
- Full Text:
- Date Issued: 2008
Do environmental factors influence the movement of estuarine fish? A case study using acoustic telemetry
- Childs, Amber-Robyn, Cowley, Paul D, Næsje, T F, Booth, Anthony J, Thorstad, Eva B, Økland, F
- Authors: Childs, Amber-Robyn , Cowley, Paul D , Næsje, T F , Booth, Anthony J , Thorstad, Eva B , Økland, F
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6772 , http://hdl.handle.net/10962/d1008070
- Description: Telemetry methods were used to investigate the influence of selected environmental variables on the position and movement of an estuarine-dependent haemulid, the spotted grunter Pomadasys commersonnii (Lacepède 1801), in the Great Fish Estuary, South Africa. Forty individuals (263–698 mm TL) were surgically implanted with acoustic coded transmitters and manually tracked during two periods (7 February to 24 March 2003; n = 20 and 29 September to 15 November 2003; n = 20). Real-time data revealed that spotted grunter are euryhaline (0–37) and are able to tolerate large variations in turbidity (4–356 FTU) and temperature (16–30 °C). However, the fish altered their position in response to large fluctuations in salinity, temperature and turbidity, which are characteristic of tidal estuarine environments. Furthermore, tidal phase had a strong influence on the position of spotted grunter in the estuary.
- Full Text:
- Date Issued: 2008
- Authors: Childs, Amber-Robyn , Cowley, Paul D , Næsje, T F , Booth, Anthony J , Thorstad, Eva B , Økland, F
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6772 , http://hdl.handle.net/10962/d1008070
- Description: Telemetry methods were used to investigate the influence of selected environmental variables on the position and movement of an estuarine-dependent haemulid, the spotted grunter Pomadasys commersonnii (Lacepède 1801), in the Great Fish Estuary, South Africa. Forty individuals (263–698 mm TL) were surgically implanted with acoustic coded transmitters and manually tracked during two periods (7 February to 24 March 2003; n = 20 and 29 September to 15 November 2003; n = 20). Real-time data revealed that spotted grunter are euryhaline (0–37) and are able to tolerate large variations in turbidity (4–356 FTU) and temperature (16–30 °C). However, the fish altered their position in response to large fluctuations in salinity, temperature and turbidity, which are characteristic of tidal estuarine environments. Furthermore, tidal phase had a strong influence on the position of spotted grunter in the estuary.
- Full Text:
- Date Issued: 2008
Drought responses of C3 and C4 (NADP-ME) Panicoid grasses
- Authors: Frole, Kristen Marie
- Date: 2008
- Subjects: Botany -- Research , Grasses -- Physiology -- South Africa , Grasses -- Effect of drought on , Grasses -- Drought tolerance , Plant-water relationships
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4193 , http://hdl.handle.net/10962/d1003762 , Botany -- Research , Grasses -- Physiology -- South Africa , Grasses -- Effect of drought on , Grasses -- Drought tolerance , Plant-water relationships
- Description: The success of C₄ plants lies in their ability to concentrate CO₂ at the site of Rubisco thereby conferring greater efficiencies of light, water and nitrogen. Such characteristics should advantage C₄ plants in arid, hot environments. However, not all C₄ subtypes are drought tolerant. The relative abundance of NADP-ME species declines with increasing aridity. Furthermore, selected species have been demonstrated as being susceptible to severe drought showing metabolic limitations of photosynthesis. However there is a lack of phylogenetic control with many of these studies. The aims of this study were to determine whether the NADP-ME subtype was inherently susceptible to drought by comparing six closely related C₃ and C₄ (NADP-ME) Panicoid grasses. Gas exchange measurements were made during a natural rainless period and a controlled drought / rewatering event. Prior to water stress, the C₄ species had higher assimilation rates (A), and water use efficiencies (WUE[subscript leaf]) than the C₃ species, while transpiration rates (E) and stomatal conductances (g[subscript s]) were similar. At low soil water content, the C₃ species reduced gs by a greater extent than the C₄ species, which maintained higher E during the driest periods. The C₄ species showed proportionally greater reductions in A than the C₃ species and hence lost their WUE[subscript leaf] and photosynthetic advantage. CO₂ response curves showed that metabolic limitation was responsible for a greater decrease in A in the C₄ type than the C₃ type during progressive drought. Upon re-watering, photosynthetic recovery was quicker in the C species than the C₄ species. Results from whole plant measurements showed that the C₄ type had a significant whole plant water use efficiency advantage over the C₃ type under well-watered conditions that was lost during severe drought due to a greater loss of leaf area through leaf mortality rather than reductions in plant level transpiration rates. The C₃ type had xylem characteristics that enhanced water-conducting efficiency, but made them vulnerable to drought. This is in contrast to the safer xylem qualities of the C₄ type, which permitted the endurance of more negative leaf water potentials than the C₃ type during low soil water content. Thus, the vulnerability of photosynthesis to severe drought in NADP-ME species potentially explains why NADP-ME species abundance around the world decreases with decreasing rainfall.
- Full Text:
- Date Issued: 2008
- Authors: Frole, Kristen Marie
- Date: 2008
- Subjects: Botany -- Research , Grasses -- Physiology -- South Africa , Grasses -- Effect of drought on , Grasses -- Drought tolerance , Plant-water relationships
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4193 , http://hdl.handle.net/10962/d1003762 , Botany -- Research , Grasses -- Physiology -- South Africa , Grasses -- Effect of drought on , Grasses -- Drought tolerance , Plant-water relationships
- Description: The success of C₄ plants lies in their ability to concentrate CO₂ at the site of Rubisco thereby conferring greater efficiencies of light, water and nitrogen. Such characteristics should advantage C₄ plants in arid, hot environments. However, not all C₄ subtypes are drought tolerant. The relative abundance of NADP-ME species declines with increasing aridity. Furthermore, selected species have been demonstrated as being susceptible to severe drought showing metabolic limitations of photosynthesis. However there is a lack of phylogenetic control with many of these studies. The aims of this study were to determine whether the NADP-ME subtype was inherently susceptible to drought by comparing six closely related C₃ and C₄ (NADP-ME) Panicoid grasses. Gas exchange measurements were made during a natural rainless period and a controlled drought / rewatering event. Prior to water stress, the C₄ species had higher assimilation rates (A), and water use efficiencies (WUE[subscript leaf]) than the C₃ species, while transpiration rates (E) and stomatal conductances (g[subscript s]) were similar. At low soil water content, the C₃ species reduced gs by a greater extent than the C₄ species, which maintained higher E during the driest periods. The C₄ species showed proportionally greater reductions in A than the C₃ species and hence lost their WUE[subscript leaf] and photosynthetic advantage. CO₂ response curves showed that metabolic limitation was responsible for a greater decrease in A in the C₄ type than the C₃ type during progressive drought. Upon re-watering, photosynthetic recovery was quicker in the C species than the C₄ species. Results from whole plant measurements showed that the C₄ type had a significant whole plant water use efficiency advantage over the C₃ type under well-watered conditions that was lost during severe drought due to a greater loss of leaf area through leaf mortality rather than reductions in plant level transpiration rates. The C₃ type had xylem characteristics that enhanced water-conducting efficiency, but made them vulnerable to drought. This is in contrast to the safer xylem qualities of the C₄ type, which permitted the endurance of more negative leaf water potentials than the C₃ type during low soil water content. Thus, the vulnerability of photosynthesis to severe drought in NADP-ME species potentially explains why NADP-ME species abundance around the world decreases with decreasing rainfall.
- Full Text:
- Date Issued: 2008
Eco-Schools and the quality of education in South Africa: Realising the potential
- Authors: Rosenberg, Eureta
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370511 , vital:66349 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122759"
- Description: Eco-Schools South Africa is increasingly being used by external partners as a framework for supporting environmental education in schools. This paper shares the findings of a recent evaluation of the programme in relation to the quality of education in South African schools. Do Eco-Schools activities help to improve the conditions of teaching and learning? Or do they take teachers and students away from their core focus? Evaluation of learner and teacher work in Eco-Schools found signs of the quality problems that currently plague the schools system, and there is evidence that the programme can add to the complexity to which many teachers struggle to respond. The evaluation also found, however, that the programme has significant potential to improve conditions for teaching and learning. The paper is an opportunity to reflect on how environmental education support for schools, in general, and Eco-Schools South Africa, in particular, can detract from and strengthen teaching and learning.
- Full Text:
- Date Issued: 2008
- Authors: Rosenberg, Eureta
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/370511 , vital:66349 , xlink:href="https://www.ajol.info/index.php/sajee/article/view/122759"
- Description: Eco-Schools South Africa is increasingly being used by external partners as a framework for supporting environmental education in schools. This paper shares the findings of a recent evaluation of the programme in relation to the quality of education in South African schools. Do Eco-Schools activities help to improve the conditions of teaching and learning? Or do they take teachers and students away from their core focus? Evaluation of learner and teacher work in Eco-Schools found signs of the quality problems that currently plague the schools system, and there is evidence that the programme can add to the complexity to which many teachers struggle to respond. The evaluation also found, however, that the programme has significant potential to improve conditions for teaching and learning. The paper is an opportunity to reflect on how environmental education support for schools, in general, and Eco-Schools South Africa, in particular, can detract from and strengthen teaching and learning.
- Full Text:
- Date Issued: 2008
Ecological role of free-living bacteria in the microbial food web of the temporarily open/closed East Kleinemonde Estuary, South Africa
- Authors: Allan, Elizabeth Louise
- Date: 2008
- Subjects: Bacterial growth -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Microbial ecology -- South Africa -- Eastern Cape , Nutrient cycles -- South Africa -- Eastern Cape , Food chains (Ecology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5666 , http://hdl.handle.net/10962/d1005351 , Bacterial growth -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Microbial ecology -- South Africa -- Eastern Cape , Nutrient cycles -- South Africa -- Eastern Cape , Food chains (Ecology)
- Description: The main aim of this study was to assess the “top-down” and “bottom-up” control of bacterial production in the small temporarily open/closed East Kleinemonde Estuary, situated on the south-eastern coastline of southern Africa. Spatial and temporal patterns in bacterial abundance, biomass and production and the importance of abiotic and biotic factors were investigated over the period May 2006 to April 2007. The trophic interactions between bacteria, phytoplankton, nanoflagellates (< 20 μm), microzooplankton (< 200 μm) and mesozooplankton (< 2 000 μm) were investigated during winter and summer. Bacterial abundance, biomass and production ranged between 1.00 × 10⁹ and 4.93 × 10⁹ cells 1⁻¹, 32.4 and 109 μg C 1⁻¹ and 0.01 and 1.99 μg C 1⁻¹ h⁻¹, respectively. With a few exceptions there were no spatial patterns in the values. Bacterial abundance, biomass and production, however, demonstrated a distinct temporal pattern with the lowest values consistently recorded during the winter months. Nanoflagellate and bacterial abundances were significantly correlated to one another (lower reaches: r = 0.818, p < 0.001; middle reaches: r = 0.628, p < 0.001; upper reaches: r = 0.484, p < 0.05) suggesting a strong predator-prey relationship. The frequency of visibly infected bacterial cells and the mean number of virus particles within each bacterial cell during this study demonstrated no temporal or spatial patterns and ranged from 0.5 to 6.1 % and 12.0 to 37.5 virus particles per bacterium, respectively. Viral infection and lysis was thus a constant source of bacterial mortality throughout the year. The estimated percentage of bacterial production removed by viral lysis ranged between 7.8 and 88.9% of the total which suggests that viral lysis represented a very important source of bacterial mortality during this study. The biological interactions between the selected components of the plankton community demonstrated that among the heterotrophic components of the plankton, the nanoflagellates were identified as the most important consumers of bacteria and small phytoplankton cells (< 20 μm). In the presence of microzooplankton the impact of the nanoflagellates on both the bacteria and phytoplankton was reduced, indicating that larger heterotrophs were preying upon the nanoflagellates. Mesozooplankton, however, appeared to exert the greatest impact on nanoflagellates. In the cascading experiments, the data suggest that mesozooplankton consume nanoflagellates, which resulted in a decrease in the predation impact of these organisms on the bacteria. This result is consistent with predator-prey cascades. The presence of the larger heterotrophs therefore, mediates the interactions between the primary bacterivores, the nanoflagellates, and the bacteria within the temporarily open/closed East Kleinemonde Estuary.
- Full Text:
- Date Issued: 2008
- Authors: Allan, Elizabeth Louise
- Date: 2008
- Subjects: Bacterial growth -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Microbial ecology -- South Africa -- Eastern Cape , Nutrient cycles -- South Africa -- Eastern Cape , Food chains (Ecology)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5666 , http://hdl.handle.net/10962/d1005351 , Bacterial growth -- South Africa -- Eastern Cape , Estuarine ecology -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Microbial ecology -- South Africa -- Eastern Cape , Nutrient cycles -- South Africa -- Eastern Cape , Food chains (Ecology)
- Description: The main aim of this study was to assess the “top-down” and “bottom-up” control of bacterial production in the small temporarily open/closed East Kleinemonde Estuary, situated on the south-eastern coastline of southern Africa. Spatial and temporal patterns in bacterial abundance, biomass and production and the importance of abiotic and biotic factors were investigated over the period May 2006 to April 2007. The trophic interactions between bacteria, phytoplankton, nanoflagellates (< 20 μm), microzooplankton (< 200 μm) and mesozooplankton (< 2 000 μm) were investigated during winter and summer. Bacterial abundance, biomass and production ranged between 1.00 × 10⁹ and 4.93 × 10⁹ cells 1⁻¹, 32.4 and 109 μg C 1⁻¹ and 0.01 and 1.99 μg C 1⁻¹ h⁻¹, respectively. With a few exceptions there were no spatial patterns in the values. Bacterial abundance, biomass and production, however, demonstrated a distinct temporal pattern with the lowest values consistently recorded during the winter months. Nanoflagellate and bacterial abundances were significantly correlated to one another (lower reaches: r = 0.818, p < 0.001; middle reaches: r = 0.628, p < 0.001; upper reaches: r = 0.484, p < 0.05) suggesting a strong predator-prey relationship. The frequency of visibly infected bacterial cells and the mean number of virus particles within each bacterial cell during this study demonstrated no temporal or spatial patterns and ranged from 0.5 to 6.1 % and 12.0 to 37.5 virus particles per bacterium, respectively. Viral infection and lysis was thus a constant source of bacterial mortality throughout the year. The estimated percentage of bacterial production removed by viral lysis ranged between 7.8 and 88.9% of the total which suggests that viral lysis represented a very important source of bacterial mortality during this study. The biological interactions between the selected components of the plankton community demonstrated that among the heterotrophic components of the plankton, the nanoflagellates were identified as the most important consumers of bacteria and small phytoplankton cells (< 20 μm). In the presence of microzooplankton the impact of the nanoflagellates on both the bacteria and phytoplankton was reduced, indicating that larger heterotrophs were preying upon the nanoflagellates. Mesozooplankton, however, appeared to exert the greatest impact on nanoflagellates. In the cascading experiments, the data suggest that mesozooplankton consume nanoflagellates, which resulted in a decrease in the predation impact of these organisms on the bacteria. This result is consistent with predator-prey cascades. The presence of the larger heterotrophs therefore, mediates the interactions between the primary bacterivores, the nanoflagellates, and the bacteria within the temporarily open/closed East Kleinemonde Estuary.
- Full Text:
- Date Issued: 2008
Economic valuation of communal rangelands in the Eastern Cape Province of South Africa
- Authors: Gombakomba, Gift
- Date: 2008
- Subjects: Rangelands -- South Africa -- Eastern Cape -- Evaluation , Rural development -- South Africa -- Eastern Cape -- Evaluation , Commons -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11166 , http://hdl.handle.net/10353/351 , Rangelands -- South Africa -- Eastern Cape -- Evaluation , Rural development -- South Africa -- Eastern Cape -- Evaluation , Commons -- South Africa -- Eastern Cape
- Description: The exploitation and conversion of rangeland ecosystems is often explained by economists as being the result of an undervaluation of the goods and services provided by the rangelands. Undervaluation of rangelands may contribute to their mismanagement or their transformation to monoculture, such as livestock or gathering. Similarly, this may lead to inappropriate policy recommendations and prescriptions. This study undertakes a valuation exercise in an effort to address causes of undervaluation. The objective of the study is to estimate the annual direct, indirect and non-use values per household of communal rangelands in the Eastern Cape Province, based on both primary and secondary data. The exercise incorporates the two major direct uses, both marketed and non-marketed, of rangelands - livestock and gathering. Contingent valuation method based on stated preferences by individual household was used to value the indirect and non-use values of the communal rangelands (e.g. erosion protection and burial sites). Data was collected using PRAs, structured questionnaires and interviews by trained enumerators. The study shows that half of the households owned livestock, which is the main economic use of the rangelands and gathering of natural resources also made an economic contribution. Every household was involved in collection of range resources such as fuel wood, wild fruits, thatch grass, building poles, hunting, fishing make a significant contribution to the direct use values: in the case of gathering it shows that there is “hidden harvest” of many of the natural resources from the rangelands. Indirect and non-use values are shown to be important in the communal areas but are difficult to quantify; the results of these are based on qualitative analysis. Keywords: communal rangelands, demand curve, direct use values, indirect use values, individuals’ preferences, non-use values, willingness-to-accept and willingness-to-pay.
- Full Text:
- Date Issued: 2008
- Authors: Gombakomba, Gift
- Date: 2008
- Subjects: Rangelands -- South Africa -- Eastern Cape -- Evaluation , Rural development -- South Africa -- Eastern Cape -- Evaluation , Commons -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc Agric (Agricultural Economics)
- Identifier: vital:11166 , http://hdl.handle.net/10353/351 , Rangelands -- South Africa -- Eastern Cape -- Evaluation , Rural development -- South Africa -- Eastern Cape -- Evaluation , Commons -- South Africa -- Eastern Cape
- Description: The exploitation and conversion of rangeland ecosystems is often explained by economists as being the result of an undervaluation of the goods and services provided by the rangelands. Undervaluation of rangelands may contribute to their mismanagement or their transformation to monoculture, such as livestock or gathering. Similarly, this may lead to inappropriate policy recommendations and prescriptions. This study undertakes a valuation exercise in an effort to address causes of undervaluation. The objective of the study is to estimate the annual direct, indirect and non-use values per household of communal rangelands in the Eastern Cape Province, based on both primary and secondary data. The exercise incorporates the two major direct uses, both marketed and non-marketed, of rangelands - livestock and gathering. Contingent valuation method based on stated preferences by individual household was used to value the indirect and non-use values of the communal rangelands (e.g. erosion protection and burial sites). Data was collected using PRAs, structured questionnaires and interviews by trained enumerators. The study shows that half of the households owned livestock, which is the main economic use of the rangelands and gathering of natural resources also made an economic contribution. Every household was involved in collection of range resources such as fuel wood, wild fruits, thatch grass, building poles, hunting, fishing make a significant contribution to the direct use values: in the case of gathering it shows that there is “hidden harvest” of many of the natural resources from the rangelands. Indirect and non-use values are shown to be important in the communal areas but are difficult to quantify; the results of these are based on qualitative analysis. Keywords: communal rangelands, demand curve, direct use values, indirect use values, individuals’ preferences, non-use values, willingness-to-accept and willingness-to-pay.
- Full Text:
- Date Issued: 2008
Ectomycorrhizas in association with Pinus patula in Sabie, South Africa
- Hawley, Greer L, Taylor, A F S, Dames, Joanna F
- Authors: Hawley, Greer L , Taylor, A F S , Dames, Joanna F
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6475 , http://hdl.handle.net/10962/d1006163 , http://www.scielo.org.za/scielo.php?pid=S0038-23532008000400011&script=sci_arttext
- Description: Forestry is an economically important industry in South Africa,involving extensive exotic plantations of Eucalyptus, Pinus and Acacia species. These tree species have fungal associations, such as ectomycorrhizas, that have become locally naturalized. The forestry industry is increasingly faced with problems of long-term sustainability, increasing soil acidity and depletion of soil nutrients. It is, therefore, essential that the fundamental importance of the ectomycorrhizal (ECM) symbioses in the nutrient cycling, growth, health and survival of these tree species should not be ignored. Research on the species diversity of ECM fungi associated with forestry plant species has been hampered by the difficulty of identifying the fungi involved in the symbiosis. This investigation focused on the ECM fungi associated with Pinus patula (Schlecht. et Cham.) grown in managed plantations in the Sabie region, Mpumalanga province, South Africa. ECM roots were morphotyped and DNA was extracted. The internal transcribed spacer (ITS) region was amplified using the ITS 1F and ITS 4 primers. The sequences were BLASTed using the GenBank and UNITE databases. Twenty-seven extractions were successfully amplified representing 17 different morphotypes. Of the 27 sequences, 21 were identified as ECM fungi and, from the BLAST results, eleven different ECM species could be identified. Selected ECM root types were morphologically and anatomically described according to root morphology, mantle structure, specialized hyphae and rhizomorph arrangement. Seven dominant field types were described and identified as two Amanita species, Scleroderma citrinum, a suilloid species, Thelephora terrestris, a tometelloid species and one resembled an Albatrellus species.
- Full Text:
- Date Issued: 2008
- Authors: Hawley, Greer L , Taylor, A F S , Dames, Joanna F
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6475 , http://hdl.handle.net/10962/d1006163 , http://www.scielo.org.za/scielo.php?pid=S0038-23532008000400011&script=sci_arttext
- Description: Forestry is an economically important industry in South Africa,involving extensive exotic plantations of Eucalyptus, Pinus and Acacia species. These tree species have fungal associations, such as ectomycorrhizas, that have become locally naturalized. The forestry industry is increasingly faced with problems of long-term sustainability, increasing soil acidity and depletion of soil nutrients. It is, therefore, essential that the fundamental importance of the ectomycorrhizal (ECM) symbioses in the nutrient cycling, growth, health and survival of these tree species should not be ignored. Research on the species diversity of ECM fungi associated with forestry plant species has been hampered by the difficulty of identifying the fungi involved in the symbiosis. This investigation focused on the ECM fungi associated with Pinus patula (Schlecht. et Cham.) grown in managed plantations in the Sabie region, Mpumalanga province, South Africa. ECM roots were morphotyped and DNA was extracted. The internal transcribed spacer (ITS) region was amplified using the ITS 1F and ITS 4 primers. The sequences were BLASTed using the GenBank and UNITE databases. Twenty-seven extractions were successfully amplified representing 17 different morphotypes. Of the 27 sequences, 21 were identified as ECM fungi and, from the BLAST results, eleven different ECM species could be identified. Selected ECM root types were morphologically and anatomically described according to root morphology, mantle structure, specialized hyphae and rhizomorph arrangement. Seven dominant field types were described and identified as two Amanita species, Scleroderma citrinum, a suilloid species, Thelephora terrestris, a tometelloid species and one resembled an Albatrellus species.
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- Date Issued: 2008