Cutting tradition: the political regulation of traditional circumcision rites in South Africa's liberal democratic order
- Authors: Vincent, Louise
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141922 , vital:38016 , DOI: 10.1080/03057070701832890
- Description: The South African Xhosa ethnic group, the majority of whom live in the country's Eastern Cape province, are one of several ethnic groups in southern Africa that practise the ritual of circumcision as part of a rite admitting boys to manhood. Recent years have seen a rise in casualties among those participating in traditional circumcision rites. Since 1995 more than 6,000 boys have been admitted to Eastern Cape hospitals, more than 300 have died and 76 have had their genitalia amputated due to botched circumcisions. The state has responded by putting in place a variety of mechanisms to regulate the practice, most recently in the form of the 2005 Children's Bill which gives male children the right to refuse circumcision and makes those who circumcise a child against his will guilty of an offence punishable by imprisonment. Attempts by the state to regulate traditional practices (of which circumcision is just one and virginity testing is another) have been met with outrage and resistance in some quarters.
- Full Text:
- Date Issued: 2008
- Authors: Vincent, Louise
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/141922 , vital:38016 , DOI: 10.1080/03057070701832890
- Description: The South African Xhosa ethnic group, the majority of whom live in the country's Eastern Cape province, are one of several ethnic groups in southern Africa that practise the ritual of circumcision as part of a rite admitting boys to manhood. Recent years have seen a rise in casualties among those participating in traditional circumcision rites. Since 1995 more than 6,000 boys have been admitted to Eastern Cape hospitals, more than 300 have died and 76 have had their genitalia amputated due to botched circumcisions. The state has responded by putting in place a variety of mechanisms to regulate the practice, most recently in the form of the 2005 Children's Bill which gives male children the right to refuse circumcision and makes those who circumcise a child against his will guilty of an offence punishable by imprisonment. Attempts by the state to regulate traditional practices (of which circumcision is just one and virginity testing is another) have been met with outrage and resistance in some quarters.
- Full Text:
- Date Issued: 2008
Decentralisation and development: the contradictions of local government in Uganda with specific reference to Masindi and Sembabule districts
- Authors: Galiwango, Wasswa Hassan
- Date: 2008
- Subjects: Decentralization in government -- Uganda , Local government -- Uganda , Uganda -- Politics and government
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8238 , http://hdl.handle.net/10948/780 , Decentralization in government -- Uganda , Local government -- Uganda , Uganda -- Politics and government
- Description: Decentralisation is the process through which Central Government transfers authority and functions to sub-national units of the Government and it traces its origin in Uganda from the “ bush” period (1981 – 1986) when Resistance Committees were established by the NRM/A in the Luwero triangle. The Mamdani Commission Report of 1987 on the Local Government system in Uganda recommended devolution of powers. Subsequently, decentralisation was launched in 1992, constitutionalised by the 1995 Constitution, and operationalised by the Local Governments Act (LGA) in 1997. Among the services devolved were education and health, which this study used as case studies to illustrate whether decentralisation has enhanced development in Uganda during the period 1993 – 2006. The study used both primary and secondary data in analysing the linkage between decentralisation and development in the two selected districts in Uganda, namely Masindi and Sembabule. Primary data was collected through interviews, questionnaires and focus group discussions while secondary data was gathered through a literature survey of relevant textbooks, newspapers, reports, legislation and journals. The findings of the study established that if decentralisation is properly planned and implemented it can make a meaningful contribution to enhancing development. However, since decentralisation is a process and not a once-off project, it evolves from one stage to another and, as it does so, it also unfolds new challenges and contradictions that need to be effectively addressed. These challenges include aspects relating to the legal framework, as well as political, fiscal and administrative decentralisation. The study recommended mitigation measures to enhance the efficiency, effectiveness, accountability, transparency, and subsequently the quality of services delivered (development) under decentralised local governance in Uganda.
- Full Text:
- Date Issued: 2008
- Authors: Galiwango, Wasswa Hassan
- Date: 2008
- Subjects: Decentralization in government -- Uganda , Local government -- Uganda , Uganda -- Politics and government
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:8238 , http://hdl.handle.net/10948/780 , Decentralization in government -- Uganda , Local government -- Uganda , Uganda -- Politics and government
- Description: Decentralisation is the process through which Central Government transfers authority and functions to sub-national units of the Government and it traces its origin in Uganda from the “ bush” period (1981 – 1986) when Resistance Committees were established by the NRM/A in the Luwero triangle. The Mamdani Commission Report of 1987 on the Local Government system in Uganda recommended devolution of powers. Subsequently, decentralisation was launched in 1992, constitutionalised by the 1995 Constitution, and operationalised by the Local Governments Act (LGA) in 1997. Among the services devolved were education and health, which this study used as case studies to illustrate whether decentralisation has enhanced development in Uganda during the period 1993 – 2006. The study used both primary and secondary data in analysing the linkage between decentralisation and development in the two selected districts in Uganda, namely Masindi and Sembabule. Primary data was collected through interviews, questionnaires and focus group discussions while secondary data was gathered through a literature survey of relevant textbooks, newspapers, reports, legislation and journals. The findings of the study established that if decentralisation is properly planned and implemented it can make a meaningful contribution to enhancing development. However, since decentralisation is a process and not a once-off project, it evolves from one stage to another and, as it does so, it also unfolds new challenges and contradictions that need to be effectively addressed. These challenges include aspects relating to the legal framework, as well as political, fiscal and administrative decentralisation. The study recommended mitigation measures to enhance the efficiency, effectiveness, accountability, transparency, and subsequently the quality of services delivered (development) under decentralised local governance in Uganda.
- Full Text:
- Date Issued: 2008
Demand-side management of internet bandwidth
- Authors: Halse, Guy A
- Date: 2008
- Language: English
- Type: Conference paper
- Identifier: vital:6607 , http://hdl.handle.net/10962/d1009463
- Description: Presentation on the demand-side management of Internet bandwidth, using Rhodes University as a case study, as presented at the DITCHE national techie event in September 2008.
- Full Text:
- Date Issued: 2008
- Authors: Halse, Guy A
- Date: 2008
- Language: English
- Type: Conference paper
- Identifier: vital:6607 , http://hdl.handle.net/10962/d1009463
- Description: Presentation on the demand-side management of Internet bandwidth, using Rhodes University as a case study, as presented at the DITCHE national techie event in September 2008.
- Full Text:
- Date Issued: 2008
Depressogenic cognitive schemas, levels of depression and hopelessness among individuals diagnosed with unipolar mood disorder
- Authors: Du Preez, Shereen
- Date: 2008
- Subjects: Neuropsychiatry , Depression, Mental -- South Africa , Depressed persons -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9899 , http://hdl.handle.net/10948/1074 , Neuropsychiatry , Depression, Mental -- South Africa , Depressed persons -- South Africa
- Description: While mood disorders rank within the top ten disabilities worldwide, there has been limited research done on cognitive schemas and the role they play in the development of mood disorders in South Africa. Cognitive conceptualisations of depression typically emphasize the schema-based automatic processing of information. Beck (1967, 1976 & 1987) suggested that schematically driven automatic thinking is a key element in depressive disorders. Research in the field of depression has identified cognitive schemas as a factor which increases an individual’s diathesis to depression. The primary aim of this research is to explore and describe maladaptive cognitive schemas, hopelessness and levels of depression amongst individuals diagnosed with Unipolar Mood Disorder. A further aim of the research has been to explore the relationship between maladaptive cognitive schemas and hopelessness as a diathesis to depression. In order to achieve the objectives, data was collected from a sample of 50 inpatients diagnosed with Unipolar Mood Disorder. The following measures were used: Young’s Schema Questionnaire, Beck's Depression Inventory – 2nd edition and Beck’s Hopelessness Scale. The research is quantitative in nature and takes the form of an exploratory-descriptive study. Data has been analysed by means of descriptive statistics in order to identify the mean, ranges and standard deviation of the measures used. Cross-tabulations have been used to further explore the relationship between the variables mentioned above. It was found that a statistically significant correlation exists between the BDI, BHS and YSQ. Maladaptive cognitive schemas were found to have a strong positive correlation 4 to depression, whereas hopelessness was found to have a less significant role in Unipolar Mood Disorder. The most significant schemas found in relation to hopelessness, were the Social Isolation, Unrelenting Standards and Pessimism schemas. With regards to depression, the most significant schemas were found to be Mistrust, Practical Incompetence, Vulnerability, Subjugation, Self-Sacrifice, Emotional Inhibition, Unrelenting Standards, Entitlement, Insufficient Self-Control, Admiration, Pessimism and Self-Punitiveness. All the above mentioned variables proved to have a statistically significant relationship. The findings of this research study are for the most part consistent with the literature on depression, hopelessness and cognitive vulnerabilities, and all of the above mentioned concepts have been found to be related.
- Full Text:
- Date Issued: 2008
- Authors: Du Preez, Shereen
- Date: 2008
- Subjects: Neuropsychiatry , Depression, Mental -- South Africa , Depressed persons -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9899 , http://hdl.handle.net/10948/1074 , Neuropsychiatry , Depression, Mental -- South Africa , Depressed persons -- South Africa
- Description: While mood disorders rank within the top ten disabilities worldwide, there has been limited research done on cognitive schemas and the role they play in the development of mood disorders in South Africa. Cognitive conceptualisations of depression typically emphasize the schema-based automatic processing of information. Beck (1967, 1976 & 1987) suggested that schematically driven automatic thinking is a key element in depressive disorders. Research in the field of depression has identified cognitive schemas as a factor which increases an individual’s diathesis to depression. The primary aim of this research is to explore and describe maladaptive cognitive schemas, hopelessness and levels of depression amongst individuals diagnosed with Unipolar Mood Disorder. A further aim of the research has been to explore the relationship between maladaptive cognitive schemas and hopelessness as a diathesis to depression. In order to achieve the objectives, data was collected from a sample of 50 inpatients diagnosed with Unipolar Mood Disorder. The following measures were used: Young’s Schema Questionnaire, Beck's Depression Inventory – 2nd edition and Beck’s Hopelessness Scale. The research is quantitative in nature and takes the form of an exploratory-descriptive study. Data has been analysed by means of descriptive statistics in order to identify the mean, ranges and standard deviation of the measures used. Cross-tabulations have been used to further explore the relationship between the variables mentioned above. It was found that a statistically significant correlation exists between the BDI, BHS and YSQ. Maladaptive cognitive schemas were found to have a strong positive correlation 4 to depression, whereas hopelessness was found to have a less significant role in Unipolar Mood Disorder. The most significant schemas found in relation to hopelessness, were the Social Isolation, Unrelenting Standards and Pessimism schemas. With regards to depression, the most significant schemas were found to be Mistrust, Practical Incompetence, Vulnerability, Subjugation, Self-Sacrifice, Emotional Inhibition, Unrelenting Standards, Entitlement, Insufficient Self-Control, Admiration, Pessimism and Self-Punitiveness. All the above mentioned variables proved to have a statistically significant relationship. The findings of this research study are for the most part consistent with the literature on depression, hopelessness and cognitive vulnerabilities, and all of the above mentioned concepts have been found to be related.
- Full Text:
- Date Issued: 2008
Deriving narrow syntax through constraints on information structure : a parallel between linguistic models of displacement and database theory
- Authors: de Vos, Mark
- 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
- 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
Determination of the optimal water temperature for the culture of juvenile dusky kob Argyrosomus japonicus Temminck and Schlegel 1843:
- Collett, Paul D, Vine, Niall G, Kaiser, Horst, Baxter, Jeremy
- Authors: Collett, Paul D , Vine, Niall G , Kaiser, Horst , Baxter, Jeremy
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142804 , vital:38118 , DOI: 10.1111/j.1365-2109.2008.01960.x
- Description: The effects of temperature on growth, food conversion ratio (FCR) and feeding intensity of juvenile dusky kob Argyrosomus japonicus (23.7±2.6 g fish−1) were assessed over the temperature range 17.5–28.5°C in a 42 day growth trial. Growth increased with increasing temperature up to an optimum after which it declined. Specific growth rates were 2.05% and 1.2% day−1 for the fastest (25.3 °C) and the slowest (17.5 °C) treatments respectively. Food conversion ratio peaked at a lower temperature than growth. Optimal (0.72 kg kg gain−1) and least efficient (1.40 kg kg gain−1) FCR were found at 21.7 and 17.5°C respectively. Feeding intensity was linearly related to temperature within the range of 17.5–28.5°C. These results corresponded to the thermal preference (25–26.4°C) and natural temperature distribution (12–28°C) of South African dusky kob. Determination of the temperature range that does not limit growth is a prerequisite to assess the relationship between growth and environmental variables such as light intensity, feeding regime and stocking density. Consequently, experiments to determine the effects of these environmental variables on growth and aquaculture potential of dusky kob should be conducted at 24–26°C.
- Full Text:
- Date Issued: 2008
- Authors: Collett, Paul D , Vine, Niall G , Kaiser, Horst , Baxter, Jeremy
- Date: 2008
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142804 , vital:38118 , DOI: 10.1111/j.1365-2109.2008.01960.x
- Description: The effects of temperature on growth, food conversion ratio (FCR) and feeding intensity of juvenile dusky kob Argyrosomus japonicus (23.7±2.6 g fish−1) were assessed over the temperature range 17.5–28.5°C in a 42 day growth trial. Growth increased with increasing temperature up to an optimum after which it declined. Specific growth rates were 2.05% and 1.2% day−1 for the fastest (25.3 °C) and the slowest (17.5 °C) treatments respectively. Food conversion ratio peaked at a lower temperature than growth. Optimal (0.72 kg kg gain−1) and least efficient (1.40 kg kg gain−1) FCR were found at 21.7 and 17.5°C respectively. Feeding intensity was linearly related to temperature within the range of 17.5–28.5°C. These results corresponded to the thermal preference (25–26.4°C) and natural temperature distribution (12–28°C) of South African dusky kob. Determination of the temperature range that does not limit growth is a prerequisite to assess the relationship between growth and environmental variables such as light intensity, feeding regime and stocking density. Consequently, experiments to determine the effects of these environmental variables on growth and aquaculture potential of dusky kob should be conducted at 24–26°C.
- 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
Developing principles for research about young women and abortion: a feminist analysis of difficulties in current South African studies
- Authors: Macleod, Catriona I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6292 , http://hdl.handle.net/10962/d1014716
- Description: Soon after the first democratic elections in South Africa in 1994, the Choice on Termination of Pregnancy (CTOP) Act of 1996, which legalised abortion for the first time, was passed. Since the introduction of the CTOP, a number of studies have been conducted on abortion in South Africa. Many have taken a health-related focus, but some research on young women and abortion has also been conducted, and it is to this (published) research that this article speaks. Two facts highlight the importance of this kind of research in the context of the abortion debate. Firstly, data from the Department of Health indicate that from 1997 to mid-2006, 12% of women undergoing terminations in the provinces in which age-related data are available were under the age of 18 (Department of Health: 2006). Secondly, the subsection of the Act allowing minors to request abortions without parental consent has caused some controversy. For example, the Christian Lawyers Association filed a suit in the Pretoria High Court in 2003, arguing that the above-mentioned subsection was unconstitutional. Their application was not successful. The research conducted on young women and abortion is etched against a background of change and contradiction in young people’s lives in South Africa. In addition to enabling legislation on termination of pregnancy, which is premised on the rights-based approach of the first democratically elected government of South Africa, various opportunities and challenges define the lives of young women. Specifically in relation to sexual and reproductive health, the Department of Health’s National Adolescent Friendly Clinic Initiative aims to make family planning and other services more accessible and acceptable to young women (Dickson-Tetteh et al., 2001). However,HIV/AIDS and “safe sex” programmes define sex as dangerous and individual young women as responsible for close monitoring of heterosexual spaces. The Child Support Grant, shown to enable functional mothering (Case et al., 2005), has sparked controversy in terms of providing perverse incentives for poor young women to conceive (a claim refuted by the research – Makiwane & Udjo, 2005). Young, black and poor women who conceive are, in particular, stigmatised and teenage pregnancy is in many respects racialised (Macleod & Durrheim, 2002). In this paper I highlight some of the problems in the research conducted on young women and abortion in South Africa since the legalisation of abortion. The specific aim of the paper is, through this analysis, to draw out feminist principles that should be considered in this kind of research. My argument draws on postcolonial feminisms that theorise the multiplicity of oppression along gender and, inter alia, race, class, age and location lines (Macleod, 2006). The paper is premised on the assumption that, in a field as fraught with gendered, race and class politics as abortion, regardless of the method used, researchers need to inspect the ideological implications of their work, and to be vigilant about their scholastic practices, and any claims legitimately made.
- Full Text:
- Date Issued: 2008
- Authors: Macleod, Catriona I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6292 , http://hdl.handle.net/10962/d1014716
- Description: Soon after the first democratic elections in South Africa in 1994, the Choice on Termination of Pregnancy (CTOP) Act of 1996, which legalised abortion for the first time, was passed. Since the introduction of the CTOP, a number of studies have been conducted on abortion in South Africa. Many have taken a health-related focus, but some research on young women and abortion has also been conducted, and it is to this (published) research that this article speaks. Two facts highlight the importance of this kind of research in the context of the abortion debate. Firstly, data from the Department of Health indicate that from 1997 to mid-2006, 12% of women undergoing terminations in the provinces in which age-related data are available were under the age of 18 (Department of Health: 2006). Secondly, the subsection of the Act allowing minors to request abortions without parental consent has caused some controversy. For example, the Christian Lawyers Association filed a suit in the Pretoria High Court in 2003, arguing that the above-mentioned subsection was unconstitutional. Their application was not successful. The research conducted on young women and abortion is etched against a background of change and contradiction in young people’s lives in South Africa. In addition to enabling legislation on termination of pregnancy, which is premised on the rights-based approach of the first democratically elected government of South Africa, various opportunities and challenges define the lives of young women. Specifically in relation to sexual and reproductive health, the Department of Health’s National Adolescent Friendly Clinic Initiative aims to make family planning and other services more accessible and acceptable to young women (Dickson-Tetteh et al., 2001). However,HIV/AIDS and “safe sex” programmes define sex as dangerous and individual young women as responsible for close monitoring of heterosexual spaces. The Child Support Grant, shown to enable functional mothering (Case et al., 2005), has sparked controversy in terms of providing perverse incentives for poor young women to conceive (a claim refuted by the research – Makiwane & Udjo, 2005). Young, black and poor women who conceive are, in particular, stigmatised and teenage pregnancy is in many respects racialised (Macleod & Durrheim, 2002). In this paper I highlight some of the problems in the research conducted on young women and abortion in South Africa since the legalisation of abortion. The specific aim of the paper is, through this analysis, to draw out feminist principles that should be considered in this kind of research. My argument draws on postcolonial feminisms that theorise the multiplicity of oppression along gender and, inter alia, race, class, age and location lines (Macleod, 2006). The paper is premised on the assumption that, in a field as fraught with gendered, race and class politics as abortion, regardless of the method used, researchers need to inspect the ideological implications of their work, and to be vigilant about their scholastic practices, and any claims legitimately made.
- Full Text:
- Date Issued: 2008
Development and validation of the Xhosa translations of the Beck Inventories: 1. Challenges of the translation process
- Steele, Gary I, Edwards, David J A
- Authors: Steele, Gary I , Edwards, David J A
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6248 , http://hdl.handle.net/10962/d1007866
- Description: This article describes the translation of the Beck Depression Inventory-II, the Beck Hopeless Scale, and the Beck Anxiety Inventory, into Xhosa the language spoken in the Eastern Cape of South Africa. The processes of translation, back-translation and committee discussion failed to yield trustworthy translations because of practical difficulties in working with translators. Critical words and phrases were identified which gave rise to lack of agreement. For each, a range of options was generated and the advantages and disadvantages evaluated in terms of criteria such as conceptual and idiomatic equivalence, and extensiveness of usage. Examples are given of the problems encountered and the way in which final decisions were made. A pilot clinical trial demonstrated the acceptability of the translated Instruments. Two further articles report the psychometric evaluation of the translated scales.
- Full Text:
- Date Issued: 2008
- Authors: Steele, Gary I , Edwards, David J A
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6248 , http://hdl.handle.net/10962/d1007866
- Description: This article describes the translation of the Beck Depression Inventory-II, the Beck Hopeless Scale, and the Beck Anxiety Inventory, into Xhosa the language spoken in the Eastern Cape of South Africa. The processes of translation, back-translation and committee discussion failed to yield trustworthy translations because of practical difficulties in working with translators. Critical words and phrases were identified which gave rise to lack of agreement. For each, a range of options was generated and the advantages and disadvantages evaluated in terms of criteria such as conceptual and idiomatic equivalence, and extensiveness of usage. Examples are given of the problems encountered and the way in which final decisions were made. A pilot clinical trial demonstrated the acceptability of the translated Instruments. Two further articles report the psychometric evaluation of the translated scales.
- 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
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