The effect of energy and protein nutritional levels on production of breeding ostriches
- Authors: Brand, Zanell
- Date: 2002
- Subjects: Ostriches -- Nutrition , Ostriches -- Breeding--South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5805 , http://hdl.handle.net/10962/d1006312 , Ostriches -- Nutrition , Ostriches -- Breeding--South Africa
- Description: Adequate and appropriate nutrition is essential for the production of high quality commercially farmed animal species. Although South Africa has had a well-established ostrich industry for over a century, little information on ostrich nutrition, in particular the specific nutritional requirements at different stages of production, is available. The industry has consequently relied heavily on data derived from poultry and pigs, but this has often proved to be unsatisfactory for ostriches and has resulted in serious nutritional-related problems. Recent studies on the metabolisable energy of specific components of diet formulations and balanced diets have indicated that ostriches have enhanced digestibility compared with poultry and pigs. At the same time, in the present economic climate, it is necessary to find cost-effective diets for breeding birds without compromising egg and chick production. This study primarily assessed the effect of different dietary protein and energy levels on production parameters and body condition of breeding female and male ostriches. The energy content of the diet appears to be the main constraint to egg production and breeders on low energy diets laid fewer eggs and lost more body condition compared with breeders fed higher energy diets. A diet with 8.5 MJ/kg DM and 10% protein with well balanced amino acids appears to be sufficient for female breeders without compromising production and a diet with 7.5 MJ/kg DM and 10% protein appears suitable for breeding male ostriches. Different dietary energy and protein levels similarly had little or no effect on egg quality and composition. This study also assessed the carry-over effect of the nutritional regime in one year on the production in the following breeding season. Females fed diets as low as 7.5 MJ/kg ME in the previous breeding season produced significantly fewer eggs in the next breeding season, which resulted in lower chick production. Energy had no effect on the percentage infertile eggs or on the initial egg weight. Different levels of dietary protein had no effect on egg production, egg weight, fertility, hatchability and initial chick weight.
- Full Text:
- Date Issued: 2002
- Authors: Brand, Zanell
- Date: 2002
- Subjects: Ostriches -- Nutrition , Ostriches -- Breeding--South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5805 , http://hdl.handle.net/10962/d1006312 , Ostriches -- Nutrition , Ostriches -- Breeding--South Africa
- Description: Adequate and appropriate nutrition is essential for the production of high quality commercially farmed animal species. Although South Africa has had a well-established ostrich industry for over a century, little information on ostrich nutrition, in particular the specific nutritional requirements at different stages of production, is available. The industry has consequently relied heavily on data derived from poultry and pigs, but this has often proved to be unsatisfactory for ostriches and has resulted in serious nutritional-related problems. Recent studies on the metabolisable energy of specific components of diet formulations and balanced diets have indicated that ostriches have enhanced digestibility compared with poultry and pigs. At the same time, in the present economic climate, it is necessary to find cost-effective diets for breeding birds without compromising egg and chick production. This study primarily assessed the effect of different dietary protein and energy levels on production parameters and body condition of breeding female and male ostriches. The energy content of the diet appears to be the main constraint to egg production and breeders on low energy diets laid fewer eggs and lost more body condition compared with breeders fed higher energy diets. A diet with 8.5 MJ/kg DM and 10% protein with well balanced amino acids appears to be sufficient for female breeders without compromising production and a diet with 7.5 MJ/kg DM and 10% protein appears suitable for breeding male ostriches. Different dietary energy and protein levels similarly had little or no effect on egg quality and composition. This study also assessed the carry-over effect of the nutritional regime in one year on the production in the following breeding season. Females fed diets as low as 7.5 MJ/kg ME in the previous breeding season produced significantly fewer eggs in the next breeding season, which resulted in lower chick production. Energy had no effect on the percentage infertile eggs or on the initial egg weight. Different levels of dietary protein had no effect on egg production, egg weight, fertility, hatchability and initial chick weight.
- Full Text:
- Date Issued: 2002
Evaluation of broiler performance under small-scale and semi-commercial farming conditions in the Northern Province
- Authors: Nembilwi, Daniel
- Date: 2002
- Subjects: Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MTech (Agricultural Management)
- Identifier: vital:10964 , http://hdl.handle.net/10948/92 , Broilers (Chickens)
- Description: Introduction: In the Northern region of the Northern Province, there is an increase in the number of small-scale and semi-commercial farms in all sectors of agriculture. This includes the production of grains, vegetables, fruits and livestock. Broiler production seemed to be a much-preferred alternative of development in community based projects and emerging farmers have shown keen interest. This is because broiler production requires less space than ruminants and is ready for human consumption within a very short period of time. Poultry production provides a constant source of income and protein with a big customer demand. By the year 2000, broiler production is expected to reach 4000 million and 7.5 million tons of poultry feeds in the world. Many countries have initiated programs aimed at improving small-scale poultry as a means of helping to bring socio- economic benefits to rural communities (Panda, 1989). In order to feed the ever rising population of 4.9 million in the Northern Province (1996 Census), there must be an increase in the production of broilers as a primary source of top quality animal protein. With the high unemployment rate (46%) in the Northern Province, self- employment projects are needed which comply with agro- processing. More than 90 community projects based on poultry production in the Northern region of the Northern Province had been established in order to reduce the high rate of unemployment. Today more people have engaged themselves in community projects especially in poultry production than ever before. Some of the constrains of broiler production at both small-scale and semi-commercial farming condition includes inadequate ventilation system. Lack of suitable health care facilities and frequently the absence of efficient marketing structures form part of the obstacles to the rapid development of poultry production. Feed costs which remain the highest input cost in the production of broilers represent between 60 to 70% or more of the total costs of broiler productions (Benyi and Habi, 1998). Lack of management skills and training for small and semi-commercial farmers makes it difficult to obtain optimum performance. The objective of this study is to evaluate the performance of broilers as influenced by environmental factors under small.
- Full Text:
- Date Issued: 2002
- Authors: Nembilwi, Daniel
- Date: 2002
- Subjects: Broilers (Chickens)
- Language: English
- Type: Thesis , Masters , MTech (Agricultural Management)
- Identifier: vital:10964 , http://hdl.handle.net/10948/92 , Broilers (Chickens)
- Description: Introduction: In the Northern region of the Northern Province, there is an increase in the number of small-scale and semi-commercial farms in all sectors of agriculture. This includes the production of grains, vegetables, fruits and livestock. Broiler production seemed to be a much-preferred alternative of development in community based projects and emerging farmers have shown keen interest. This is because broiler production requires less space than ruminants and is ready for human consumption within a very short period of time. Poultry production provides a constant source of income and protein with a big customer demand. By the year 2000, broiler production is expected to reach 4000 million and 7.5 million tons of poultry feeds in the world. Many countries have initiated programs aimed at improving small-scale poultry as a means of helping to bring socio- economic benefits to rural communities (Panda, 1989). In order to feed the ever rising population of 4.9 million in the Northern Province (1996 Census), there must be an increase in the production of broilers as a primary source of top quality animal protein. With the high unemployment rate (46%) in the Northern Province, self- employment projects are needed which comply with agro- processing. More than 90 community projects based on poultry production in the Northern region of the Northern Province had been established in order to reduce the high rate of unemployment. Today more people have engaged themselves in community projects especially in poultry production than ever before. Some of the constrains of broiler production at both small-scale and semi-commercial farming condition includes inadequate ventilation system. Lack of suitable health care facilities and frequently the absence of efficient marketing structures form part of the obstacles to the rapid development of poultry production. Feed costs which remain the highest input cost in the production of broilers represent between 60 to 70% or more of the total costs of broiler productions (Benyi and Habi, 1998). Lack of management skills and training for small and semi-commercial farmers makes it difficult to obtain optimum performance. The objective of this study is to evaluate the performance of broilers as influenced by environmental factors under small.
- Full Text:
- Date Issued: 2002
Identification and analysis of the factors that influence the development of female entrepreneurs in the informal sector
- Authors: Sokabo, Nobenguni B
- Date: 2002
- Subjects: Women-owned business enterprises -- South Africa , Small business -- South Africa , Businesswomen -- South Africa , Women in development -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10907 , http://hdl.handle.net/10948/98 , Women-owned business enterprises -- South Africa , Small business -- South Africa , Businesswomen -- South Africa , Women in development -- South Africa
- Description: There is a remarkable increase in the participation of females in business activities due to their involvement in the informal sector. These activities appear to be insignificant and not measurable because they are outside the regulatory framework, but they also absorb multitudes of the unemployable. Notwithstanding the challenges of low levels of education, lack of skills and finance as well as the need to balance reproductive and productive roles, females are under pressure to generate income through trading in small scale businesses that can hardly grow beyond subsistence level. With the meagre earnings from their activities, they ensure the survival of their families. If female entrepreneurs are developed and brought into the economic main stream, they will bring with them their unique survivalist techniques that will contribute towards economic development and growth in the country. This report examines the constraints that affect the development of female entrepreneurs in the informal sector.
- Full Text:
- Date Issued: 2002
- Authors: Sokabo, Nobenguni B
- Date: 2002
- Subjects: Women-owned business enterprises -- South Africa , Small business -- South Africa , Businesswomen -- South Africa , Women in development -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:10907 , http://hdl.handle.net/10948/98 , Women-owned business enterprises -- South Africa , Small business -- South Africa , Businesswomen -- South Africa , Women in development -- South Africa
- Description: There is a remarkable increase in the participation of females in business activities due to their involvement in the informal sector. These activities appear to be insignificant and not measurable because they are outside the regulatory framework, but they also absorb multitudes of the unemployable. Notwithstanding the challenges of low levels of education, lack of skills and finance as well as the need to balance reproductive and productive roles, females are under pressure to generate income through trading in small scale businesses that can hardly grow beyond subsistence level. With the meagre earnings from their activities, they ensure the survival of their families. If female entrepreneurs are developed and brought into the economic main stream, they will bring with them their unique survivalist techniques that will contribute towards economic development and growth in the country. This report examines the constraints that affect the development of female entrepreneurs in the informal sector.
- Full Text:
- Date Issued: 2002
Voltammetric characterization of the self-assembled monolayer (SAM) of octabutylthiophthalocyaninatoiron (II)
- Ozoemena,Kenneth, Nyokong, Tebello
- Authors: Ozoemena,Kenneth , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290419 , vital:56748 , xlink:href="https://doi.org/10.1016/S0013-4686(02)00362-6"
- Description: The fabrication of a self-assembled monolayer (SAM) of 2,3,9,10,16,17,23,24-octa (butylthio)-phthalocyaninatoiron(II) [FePc(SBu)8] on gold electrode is described. The integrity of the SAM, with respect to its ability to block certain Faradaic processes, is interrogated using cyclic voltammetric experiments in aqueous solutions. The experiments show that this SAM provide an excellent blocking capability to the Faradaic processes emanating from gold surface oxidation, underpotential deposition (UPD) of copper and redox chemistry of Fe(NH4)(SO4)2 in HClO4. It is revealed by cyclic voltammetry that an ill-defined reversible couple of the SAM of FePc(SBu)8 can be greatly improved by a simple repetitive cycling of the modified electrode in a DMF solution containing TBAP within a short space of time (ca. 2 min). This ‘activation’ process provides good information concerning the surface coverage and orientation of the monolayer. The reversible redox wave shows a potential shift of about −57 mV per pH in the pH range of 2–9. A preliminary investigation indicates that FePc(SBu)8-SAM modified gold electrode shows electrocatalytic activity toward the oxidation of L-cysteine in acidic medium. The monolayer is stable and easily reproducible. However, due to its susceptibility to destruction via oxidative and reductive desorptions, its potential application as an electrochemical sensor would be much better in acidic and neutral than alkaline environments.
- Full Text:
- Date Issued: 2002
- Authors: Ozoemena,Kenneth , Nyokong, Tebello
- Date: 2002
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/290419 , vital:56748 , xlink:href="https://doi.org/10.1016/S0013-4686(02)00362-6"
- Description: The fabrication of a self-assembled monolayer (SAM) of 2,3,9,10,16,17,23,24-octa (butylthio)-phthalocyaninatoiron(II) [FePc(SBu)8] on gold electrode is described. The integrity of the SAM, with respect to its ability to block certain Faradaic processes, is interrogated using cyclic voltammetric experiments in aqueous solutions. The experiments show that this SAM provide an excellent blocking capability to the Faradaic processes emanating from gold surface oxidation, underpotential deposition (UPD) of copper and redox chemistry of Fe(NH4)(SO4)2 in HClO4. It is revealed by cyclic voltammetry that an ill-defined reversible couple of the SAM of FePc(SBu)8 can be greatly improved by a simple repetitive cycling of the modified electrode in a DMF solution containing TBAP within a short space of time (ca. 2 min). This ‘activation’ process provides good information concerning the surface coverage and orientation of the monolayer. The reversible redox wave shows a potential shift of about −57 mV per pH in the pH range of 2–9. A preliminary investigation indicates that FePc(SBu)8-SAM modified gold electrode shows electrocatalytic activity toward the oxidation of L-cysteine in acidic medium. The monolayer is stable and easily reproducible. However, due to its susceptibility to destruction via oxidative and reductive desorptions, its potential application as an electrochemical sensor would be much better in acidic and neutral than alkaline environments.
- Full Text:
- Date Issued: 2002
Formulation and assessment of monolithic beta blocker sustained release tablets prepared by direct compression
- Authors: Kieser, Leith Faye
- Date: 2002
- Subjects: Drugs -- Dosage forms , Drugs -- Administration , Pharmacology, Experimental , Adrenergic beta blockers , Tablets (Medicine) , Tableting , Neuropharmacology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3764 , http://hdl.handle.net/10962/d1003242 , Drugs -- Dosage forms , Drugs -- Administration , Pharmacology, Experimental , Adrenergic beta blockers , Tablets (Medicine) , Tableting , Neuropharmacology
- Description: Beta blockers are commonly prescribed for the chronic treatment of hypertension, one of the most prolific disease states worldwide. The beta blockers selected for this study include acebutolol hydrochloride, labetalol hydrochloride, metoprolol tartrate oxprenolol hydrochloride and propranolol hydrochloride. All of these compounds have a short elimination half-life, necessitating multiple dose per day regimens and therefore the development of sustained release dosage forms incorporating these agents was considered beneficial in terms of extending the dosing interval, with the aim of improving patient compliance and subsequent therapeutic outcomes. Preformulation studies that were conducted included moisture content analysis by Karl Fischer titration, and DSC, a method used to predict potential interactions between the drugs and tablet excipients. Tablets were manufactured by both wet granulation and direct compression techniques, and the resultant drug release characteristics were evaluated using the USP Apparatus 3(BIO.DIS). A validated isocratic HPLC method, capable of separating the five drug candidates simultaneously, was developed and used for the analysis of drug samples. Tablet quality was assessed using analyses that included the physical assessment of weight, diameter, thickness, hardness and friability, as well as content uniformity of tablets, before and after dissolution testing. Direct compression tablet formulations containing each of the five beta blockers were successfully adapted from a prototype wet granulation matrix tablet containing metoprolol tartrate, and various formulation variables were investigated to establish,their effect on the rate and extent of drug release from these tablets. The grade and quantity of ethylcellulose used in the wet granulation and direct compression formulae influenced the release rate of some drug candidates. In addition, an alternative formulation method, involving freeze-drying of the drug with an ethylcellulose dispersion, was shown to have potential for altering release rates further. Anti-frictional agents, talc and colloidal silicon dioxide, did not affect drug release from these matrices,however, they affected the physical character:istics such as tablet weight and thickness, of the resultant tablets. All of the matrix tablets formulated were shown to release drug according to square root of time kinetics, in a sustained manner over a 22 hour period.
- Full Text:
- Date Issued: 2002
- Authors: Kieser, Leith Faye
- Date: 2002
- Subjects: Drugs -- Dosage forms , Drugs -- Administration , Pharmacology, Experimental , Adrenergic beta blockers , Tablets (Medicine) , Tableting , Neuropharmacology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3764 , http://hdl.handle.net/10962/d1003242 , Drugs -- Dosage forms , Drugs -- Administration , Pharmacology, Experimental , Adrenergic beta blockers , Tablets (Medicine) , Tableting , Neuropharmacology
- Description: Beta blockers are commonly prescribed for the chronic treatment of hypertension, one of the most prolific disease states worldwide. The beta blockers selected for this study include acebutolol hydrochloride, labetalol hydrochloride, metoprolol tartrate oxprenolol hydrochloride and propranolol hydrochloride. All of these compounds have a short elimination half-life, necessitating multiple dose per day regimens and therefore the development of sustained release dosage forms incorporating these agents was considered beneficial in terms of extending the dosing interval, with the aim of improving patient compliance and subsequent therapeutic outcomes. Preformulation studies that were conducted included moisture content analysis by Karl Fischer titration, and DSC, a method used to predict potential interactions between the drugs and tablet excipients. Tablets were manufactured by both wet granulation and direct compression techniques, and the resultant drug release characteristics were evaluated using the USP Apparatus 3(BIO.DIS). A validated isocratic HPLC method, capable of separating the five drug candidates simultaneously, was developed and used for the analysis of drug samples. Tablet quality was assessed using analyses that included the physical assessment of weight, diameter, thickness, hardness and friability, as well as content uniformity of tablets, before and after dissolution testing. Direct compression tablet formulations containing each of the five beta blockers were successfully adapted from a prototype wet granulation matrix tablet containing metoprolol tartrate, and various formulation variables were investigated to establish,their effect on the rate and extent of drug release from these tablets. The grade and quantity of ethylcellulose used in the wet granulation and direct compression formulae influenced the release rate of some drug candidates. In addition, an alternative formulation method, involving freeze-drying of the drug with an ethylcellulose dispersion, was shown to have potential for altering release rates further. Anti-frictional agents, talc and colloidal silicon dioxide, did not affect drug release from these matrices,however, they affected the physical character:istics such as tablet weight and thickness, of the resultant tablets. All of the matrix tablets formulated were shown to release drug according to square root of time kinetics, in a sustained manner over a 22 hour period.
- Full Text:
- Date Issued: 2002
Physiological and psychophysical responses of male soldiers to changes in marching gradient, speed and load
- Authors: Todd, Andrew Ivan
- Date: 2002
- Subjects: Soldiers -- South Africa -- Physiology , South Africa Army -- Physical training , Marching -- Physiological aspects , Psychophysiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5129 , http://hdl.handle.net/10962/d1005208 , Soldiers -- South Africa -- Physiology , South Africa Army -- Physical training , Marching -- Physiological aspects , Psychophysiology
- Description: The present study sought to investigate the effects of changes in gradient, under apparently optimal combinations of speed and load, on selected physiological, psychophysical and biophysical responses of military personnel. Subjects (n = 32) were required to march under level (0%), downhill (-10%) and uphill (+10%) conditions. Under each gradient, subjects marched with the following speed-load combinations: 4 km.h-1 carrying 50 kg, 5 km.h-1 carrying 35 kg and 6 km.h-1 carrying 20 kg, a total of nine experimental conditions. Subjects were required to march for six minutes under each condition. Physiological responses (HR, VO2, R, Br, VE, VT, EE) indicated that subjects were not overly taxed by the three speed-load combinations during level marching, which elicited submaximal demands. Furthermore, the results revealed that downhill marching with heavy loads results in similar responses to level marching, while lighter loads may result in significant reductions in physical demands compared to level marching. The physiological responses to uphill marching revealed that subjects were severely physically taxed under these conditions, regardless of speed-load combination. It is unlikely that soldiers would be able to maintain these intensities for an extended period without undue fatigue. It is evident from the psychophysical responses (Rating of Perceived Exertion and Body Discomfort) that subjects perceived the heavy load conditions, regardless of gradient, to be the most stressful on the cardiovascular and muscular systems. The positive gradient conditions also elicited elevated RPE and Body Discomfort responses, while lighter load downhill conditions were perceived to result in the least strain.
- Full Text:
- Date Issued: 2002
- Authors: Todd, Andrew Ivan
- Date: 2002
- Subjects: Soldiers -- South Africa -- Physiology , South Africa Army -- Physical training , Marching -- Physiological aspects , Psychophysiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5129 , http://hdl.handle.net/10962/d1005208 , Soldiers -- South Africa -- Physiology , South Africa Army -- Physical training , Marching -- Physiological aspects , Psychophysiology
- Description: The present study sought to investigate the effects of changes in gradient, under apparently optimal combinations of speed and load, on selected physiological, psychophysical and biophysical responses of military personnel. Subjects (n = 32) were required to march under level (0%), downhill (-10%) and uphill (+10%) conditions. Under each gradient, subjects marched with the following speed-load combinations: 4 km.h-1 carrying 50 kg, 5 km.h-1 carrying 35 kg and 6 km.h-1 carrying 20 kg, a total of nine experimental conditions. Subjects were required to march for six minutes under each condition. Physiological responses (HR, VO2, R, Br, VE, VT, EE) indicated that subjects were not overly taxed by the three speed-load combinations during level marching, which elicited submaximal demands. Furthermore, the results revealed that downhill marching with heavy loads results in similar responses to level marching, while lighter loads may result in significant reductions in physical demands compared to level marching. The physiological responses to uphill marching revealed that subjects were severely physically taxed under these conditions, regardless of speed-load combination. It is unlikely that soldiers would be able to maintain these intensities for an extended period without undue fatigue. It is evident from the psychophysical responses (Rating of Perceived Exertion and Body Discomfort) that subjects perceived the heavy load conditions, regardless of gradient, to be the most stressful on the cardiovascular and muscular systems. The positive gradient conditions also elicited elevated RPE and Body Discomfort responses, while lighter load downhill conditions were perceived to result in the least strain.
- Full Text:
- Date Issued: 2002
The implementation of environmental education policy in Namibia: perceptions of a range of decision-makers
- Authors: Katoma, Loini-Nyanyukweni
- Date: 2002
- Subjects: Environmental education -- Namibia , Education and state -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1563 , http://hdl.handle.net/10962/d1003445 , Environmental education -- Namibia , Education and state -- Namibia
- Description: This study is the first cycle of an action research project that focuses on the implementation of the Environmental Education Policy in Namibia. Perceptions of Namibian decision-makers were sought with regard to their understanding of the concepts ‘environment’ and ‘environmental education’, as well as to identify environmental problems and obstacles to the implementation of the Environmental Education Policy. The approach of coming up with options to address the identified problems/obstacles/constraints, was employed in this study. To this effect, interviews, a workshop, observations and reflections on the process of implementation resulted in a wealth of data. The findings shed light on possible solutions to address the identified problems and obstacles. The results revealed that community participation, skills development and the proper co-ordination of environmental education activities are imperative in addressing the obvious policy-practice gap. Decision-makers uncovered the fact that the socio-economic situation of our people necessitated pulling our resources together and working as a team. The overall perceptions are that the environment is everyone’s business and that we should zealously use it and carefully guard it, not only for ourselves but also, for the benefit of coming generations.
- Full Text:
- Date Issued: 2002
- Authors: Katoma, Loini-Nyanyukweni
- Date: 2002
- Subjects: Environmental education -- Namibia , Education and state -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1563 , http://hdl.handle.net/10962/d1003445 , Environmental education -- Namibia , Education and state -- Namibia
- Description: This study is the first cycle of an action research project that focuses on the implementation of the Environmental Education Policy in Namibia. Perceptions of Namibian decision-makers were sought with regard to their understanding of the concepts ‘environment’ and ‘environmental education’, as well as to identify environmental problems and obstacles to the implementation of the Environmental Education Policy. The approach of coming up with options to address the identified problems/obstacles/constraints, was employed in this study. To this effect, interviews, a workshop, observations and reflections on the process of implementation resulted in a wealth of data. The findings shed light on possible solutions to address the identified problems and obstacles. The results revealed that community participation, skills development and the proper co-ordination of environmental education activities are imperative in addressing the obvious policy-practice gap. Decision-makers uncovered the fact that the socio-economic situation of our people necessitated pulling our resources together and working as a team. The overall perceptions are that the environment is everyone’s business and that we should zealously use it and carefully guard it, not only for ourselves but also, for the benefit of coming generations.
- Full Text:
- Date Issued: 2002
A phenomenological investigation of Windhoek Senior Secondary school principals' perceptions and experiences of their leadership roles
- Authors: Boys, Ben
- Date: 2002
- Subjects: School principals -- Namibia Educational leadership -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1700 , http://hdl.handle.net/10962/d1003583
- Description: Namibia, having been a former colony of South Africa, was equally subjected to apartheid laws and practices. Independence, achieved in March 1990, signaled the dawn of a new era of access, equity, quality and democracy in the Namibian education sector. A unified system of educational administration, management, and control was established. The whole educational corps, especially the principals of all our schools, is expected to implement this new system as agents of change. In terms of the vision for a new Namibia, therefore, school principals are seen as occupying positions of central importance. This notion resonates strongly with recent and contemporary leadership thinking. However, a number of concerns prevalent in schools - particularly, increasing student underperformance, worsening disciplinary problems, increasing teenage pregnancy and HIV/AIDS pandemic, teacher qualification, decreasing teacher motivation, lack of training including induction for principals, inadequate support from the top (lack of a support system) and insufficient parental involvement in school matters – make the task of running schools extremely challenging and increasingly complex. How do principals experience these challenges and deal with the complex situations? How do they perceive their role, particularly in light of national aspirations and leadership theory? These are questions I think need to be explored. My research goal was to gain an understanding of Windhoek senior secondary school principals’ perceptions and experiences of their leadership role. My focus was on three purposively selected Windhoek senior secondary school principals representative of both the Namibian ethno-cultural diversity and gender. Data was collected through interviews. I found that the situations in which the principals found themselves during the pre- and post independent periods mainly determined their leadership style and behaviour, however, that did not deter their vision for the transformation of the society, as the ultimate objective and essence of their leadership. The appropriate practicing of their leadership role was being hampered by lack of induction and training, lack of a support system and insufficient parental involvement.
- Full Text:
- Date Issued: 2002
- Authors: Boys, Ben
- Date: 2002
- Subjects: School principals -- Namibia Educational leadership -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1700 , http://hdl.handle.net/10962/d1003583
- Description: Namibia, having been a former colony of South Africa, was equally subjected to apartheid laws and practices. Independence, achieved in March 1990, signaled the dawn of a new era of access, equity, quality and democracy in the Namibian education sector. A unified system of educational administration, management, and control was established. The whole educational corps, especially the principals of all our schools, is expected to implement this new system as agents of change. In terms of the vision for a new Namibia, therefore, school principals are seen as occupying positions of central importance. This notion resonates strongly with recent and contemporary leadership thinking. However, a number of concerns prevalent in schools - particularly, increasing student underperformance, worsening disciplinary problems, increasing teenage pregnancy and HIV/AIDS pandemic, teacher qualification, decreasing teacher motivation, lack of training including induction for principals, inadequate support from the top (lack of a support system) and insufficient parental involvement in school matters – make the task of running schools extremely challenging and increasingly complex. How do principals experience these challenges and deal with the complex situations? How do they perceive their role, particularly in light of national aspirations and leadership theory? These are questions I think need to be explored. My research goal was to gain an understanding of Windhoek senior secondary school principals’ perceptions and experiences of their leadership role. My focus was on three purposively selected Windhoek senior secondary school principals representative of both the Namibian ethno-cultural diversity and gender. Data was collected through interviews. I found that the situations in which the principals found themselves during the pre- and post independent periods mainly determined their leadership style and behaviour, however, that did not deter their vision for the transformation of the society, as the ultimate objective and essence of their leadership. The appropriate practicing of their leadership role was being hampered by lack of induction and training, lack of a support system and insufficient parental involvement.
- Full Text:
- Date Issued: 2002
The characterisation of a South African isolate of Cryptophlebia leucotreta Granulovirus (CIGV)
- Authors: Singh, Shalene
- Date: 2002
- Subjects: Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control -- Africa , DNA viruses
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4067 , http://hdl.handle.net/10962/d1004929 , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control -- Africa , DNA viruses
- Description: The false codling moth (FCM), Cryptophlehia Leucatreta, causes widespread damage to economically important fruit crops throughout sub-Saharan Africa. Fruit are rendered unfit for consumption once they have been stung by FCM larvae. Larval infestation of fruit can lead to significant pre-harvest losses or post-harvest waste, posing a major problem to the citrus industry. Current control of the pest includes the use of chemical pesticides. The larval form of FCM is known to be infected by a granulovirus called Cryptophlebia leucotreta granulovirus (CIGV). Granuloviruses are highly specific against their hosts and are harmless to vertebrates, plants and the environment. The development of CIGV into a biological control agent would offer an attractive and safer alternative for the control of this pest. A full characterisation of CIGV is required prior to the virus being disseminated into the environment. In this project, the characteristics of CIGV will be examined. Viral DNA was extracted from infected larvae and the DNA analysed by restriction fragment length polymorphism (RFLP). Fragmentation profiles of the South African and Cape Verde (CV3) isolates of the virus were compared, revealing distinct differences between them. The size of the CIGV-SA genome was calculated to be 112 kbp, identical to the size of the CV3 isolate. Physical maps for five restriction enzymes were constructed for the CIGV-SA genome. The alignment of these maps with maps the CV3 isolate (for the same enzymes) further highlighted the differences between the isolates. The genetic engineering of granuloviruses could significantly improve the speed of kill of these viruses. Therefore essential genes like egt and granulin were isolated (by PCR) and their position located in the genome. Both genes were sequenced and their phylogeny with other granulin and egt genes investigated. Finally, tbe incidence of CIGV in natural populations of FCM larvae was investigated, by screening field-collected larvae for the presence of the virus. CIGV was successfully detected from dot blots of larval DNA using both radiolabelled and non-radiolabelled probes and by PCR. Trends regarding the incidence of CIGV in natural populations of larvae were also determined.
- Full Text:
- Date Issued: 2002
- Authors: Singh, Shalene
- Date: 2002
- Subjects: Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control -- Africa , DNA viruses
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4067 , http://hdl.handle.net/10962/d1004929 , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control -- Africa , DNA viruses
- Description: The false codling moth (FCM), Cryptophlehia Leucatreta, causes widespread damage to economically important fruit crops throughout sub-Saharan Africa. Fruit are rendered unfit for consumption once they have been stung by FCM larvae. Larval infestation of fruit can lead to significant pre-harvest losses or post-harvest waste, posing a major problem to the citrus industry. Current control of the pest includes the use of chemical pesticides. The larval form of FCM is known to be infected by a granulovirus called Cryptophlebia leucotreta granulovirus (CIGV). Granuloviruses are highly specific against their hosts and are harmless to vertebrates, plants and the environment. The development of CIGV into a biological control agent would offer an attractive and safer alternative for the control of this pest. A full characterisation of CIGV is required prior to the virus being disseminated into the environment. In this project, the characteristics of CIGV will be examined. Viral DNA was extracted from infected larvae and the DNA analysed by restriction fragment length polymorphism (RFLP). Fragmentation profiles of the South African and Cape Verde (CV3) isolates of the virus were compared, revealing distinct differences between them. The size of the CIGV-SA genome was calculated to be 112 kbp, identical to the size of the CV3 isolate. Physical maps for five restriction enzymes were constructed for the CIGV-SA genome. The alignment of these maps with maps the CV3 isolate (for the same enzymes) further highlighted the differences between the isolates. The genetic engineering of granuloviruses could significantly improve the speed of kill of these viruses. Therefore essential genes like egt and granulin were isolated (by PCR) and their position located in the genome. Both genes were sequenced and their phylogeny with other granulin and egt genes investigated. Finally, tbe incidence of CIGV in natural populations of FCM larvae was investigated, by screening field-collected larvae for the presence of the virus. CIGV was successfully detected from dot blots of larval DNA using both radiolabelled and non-radiolabelled probes and by PCR. Trends regarding the incidence of CIGV in natural populations of larvae were also determined.
- Full Text:
- Date Issued: 2002
Effect of selected physical and production traits on the tick burdens of beef cattle
- Authors: Botha, Theunis Christoffel
- Date: 2002
- Subjects: Beef cattle -- Breeding
- Language: English
- Type: Thesis , Masters , MTech (Agricultural Management)
- Identifier: vital:10966 , http://hdl.handle.net/10948/91 , Beef cattle -- Breeding
- Description: The objective of this study was to determine the effect of selected traits such as age, sex, body weight, body length and height, body condition score (BCS), coatscore (CS), skin thickness and average skin surface temperature on tick burdens in beef cattle. Bonsmara cattle (n= 143) were used to measure visible tick counts, body condition score, coat score, skin thickness, body height and length, body weight, body surface temperature, gender and inter calving period. Measurements were taken from April to December. All animals were managed extensively on natural and cultivated pastures near George in the Southern Cape. Female animals had significantly (p<0.05) greater tick infestation (37.98±2.7) compared to male animals (16.52±1.2). Age was a significant factor (p<0.001) with the younger animals below two years having (46.40±5.26) more ticks than those of two years and older (20.15±2.44). A significant negative correlation (p<0.001; -0.29) was reported between the infestation of ticks on the animals and the age of the animal. Animals with an average body weight below 250kg had 42% (p<0.05) more ticks compared to animals with a body weight above 250kg. Age of the animal and weight were highly correlated (r= 0.70); p<0.001), while the correlation between the number of ticks per cow and the mean weight was negatively correlated (r= -0.37; p<0.001). Skin surface temperature significantly influenced tick infestation on the animals (p<0.001). The degree of infestation increased as body surface temperature exceeded 30º C. Coat score, skin thickness, body condition score and inter calving period did not significantly influence tick infestation on the animals. The infestation of ticks on the animals were significantly influenced by body height (p<0.019) and body length (p<0.001). Animals smaller than a 130cm in height had a significantly (p<0.05) greater tick infestation (36.5±5) compared to animals taller than 130cm (21.2±1.5). This trend was also observed for body length. Animals with a body length shorter than 145cm had a greater (p<0.05) average tick infestation of 41.3±4.5 compared to 23.2±1.3 to animals longer than 145cm, indicating a 44% greater tick infestation in favour of the shorter animals. For increased production and tick resistance animals should have smoother coats and be able to dissipate heat effectively.
- Full Text:
- Date Issued: 2002
- Authors: Botha, Theunis Christoffel
- Date: 2002
- Subjects: Beef cattle -- Breeding
- Language: English
- Type: Thesis , Masters , MTech (Agricultural Management)
- Identifier: vital:10966 , http://hdl.handle.net/10948/91 , Beef cattle -- Breeding
- Description: The objective of this study was to determine the effect of selected traits such as age, sex, body weight, body length and height, body condition score (BCS), coatscore (CS), skin thickness and average skin surface temperature on tick burdens in beef cattle. Bonsmara cattle (n= 143) were used to measure visible tick counts, body condition score, coat score, skin thickness, body height and length, body weight, body surface temperature, gender and inter calving period. Measurements were taken from April to December. All animals were managed extensively on natural and cultivated pastures near George in the Southern Cape. Female animals had significantly (p<0.05) greater tick infestation (37.98±2.7) compared to male animals (16.52±1.2). Age was a significant factor (p<0.001) with the younger animals below two years having (46.40±5.26) more ticks than those of two years and older (20.15±2.44). A significant negative correlation (p<0.001; -0.29) was reported between the infestation of ticks on the animals and the age of the animal. Animals with an average body weight below 250kg had 42% (p<0.05) more ticks compared to animals with a body weight above 250kg. Age of the animal and weight were highly correlated (r= 0.70); p<0.001), while the correlation between the number of ticks per cow and the mean weight was negatively correlated (r= -0.37; p<0.001). Skin surface temperature significantly influenced tick infestation on the animals (p<0.001). The degree of infestation increased as body surface temperature exceeded 30º C. Coat score, skin thickness, body condition score and inter calving period did not significantly influence tick infestation on the animals. The infestation of ticks on the animals were significantly influenced by body height (p<0.019) and body length (p<0.001). Animals smaller than a 130cm in height had a significantly (p<0.05) greater tick infestation (36.5±5) compared to animals taller than 130cm (21.2±1.5). This trend was also observed for body length. Animals with a body length shorter than 145cm had a greater (p<0.05) average tick infestation of 41.3±4.5 compared to 23.2±1.3 to animals longer than 145cm, indicating a 44% greater tick infestation in favour of the shorter animals. For increased production and tick resistance animals should have smoother coats and be able to dissipate heat effectively.
- Full Text:
- Date Issued: 2002
Rumours of war : de-constructing media discourses of HIV/AIDS in South Africa
- Authors: Connelly, Mark
- Date: 2002
- Subjects: AIDS (Disease) -- South Africa AIDS (Disease) in mass media
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3177 , http://hdl.handle.net/10962/d1007844
- Description: This paper explores discourses of HIV/AIDS evident in a South African daily newspaper from 1985 to 2000, and discusses the implications of these in terms of the way in which HIV/AIDS is constructed in society. In this paper I utilize a Foucauldian analysis of the relationship between power and knowledge. The discursive framework of the war against HIV/AIDS is used to show how different groups of subjects are positioned in relations of power. Within this the power of western science and medicine is influential and supports and informs other discourses of HIV/AIDS. I argue that the discursive framework constructing HIV/AIDS as a war does far more than provide a useful vehicle within which HIV/AIDS can be understood as it supports certain institutions and groups of people above others. The paper concludes by identifying the silenced voices of women and dissidents, and calling for greater reflection concerning the critical analysis of current issues surrounding HIV/AIDS.
- Full Text:
- Date Issued: 2002
- Authors: Connelly, Mark
- Date: 2002
- Subjects: AIDS (Disease) -- South Africa AIDS (Disease) in mass media
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3177 , http://hdl.handle.net/10962/d1007844
- Description: This paper explores discourses of HIV/AIDS evident in a South African daily newspaper from 1985 to 2000, and discusses the implications of these in terms of the way in which HIV/AIDS is constructed in society. In this paper I utilize a Foucauldian analysis of the relationship between power and knowledge. The discursive framework of the war against HIV/AIDS is used to show how different groups of subjects are positioned in relations of power. Within this the power of western science and medicine is influential and supports and informs other discourses of HIV/AIDS. I argue that the discursive framework constructing HIV/AIDS as a war does far more than provide a useful vehicle within which HIV/AIDS can be understood as it supports certain institutions and groups of people above others. The paper concludes by identifying the silenced voices of women and dissidents, and calling for greater reflection concerning the critical analysis of current issues surrounding HIV/AIDS.
- Full Text:
- Date Issued: 2002
Title not specified
- Venda men and boys, Tracey, Andrew T N
- Authors: Venda men and boys , Tracey, Andrew T N
- Date: 2002
- Subjects: Venda --(African people) , Folk Music , Mbira , Sub-Saharan African music , Africa South Africa Venda f-sa
- Language: Venda
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/112161 , vital:33554 , International Library of African Music, Rhodes University, Grahamstown, South Africa , ATC126b-01
- Description: Venda traditional music with Mbila Mutondo accompaniment
- Full Text: false
- Date Issued: 2002
- Authors: Venda men and boys , Tracey, Andrew T N
- Date: 2002
- Subjects: Venda --(African people) , Folk Music , Mbira , Sub-Saharan African music , Africa South Africa Venda f-sa
- Language: Venda
- Type: sound recordings , field recordings , sound recording-musical
- Identifier: http://hdl.handle.net/10962/112161 , vital:33554 , International Library of African Music, Rhodes University, Grahamstown, South Africa , ATC126b-01
- Description: Venda traditional music with Mbila Mutondo accompaniment
- Full Text: false
- Date Issued: 2002
Deconstructive discourse analysis: extending the methodological conversation
- Authors: Macleod, Catriona I
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6259 , http://hdl.handle.net/10962/d1007877 , http://journals.sagepub.com/doi/abs/10.1177/008124630203200103
- Description: Discourse analysis is increasingly becoming a methodology of preference amongst qualitative researchers. There is a danger, however, of it being viewed as a bounded and uncontested domain of research practice. As discourse analysis is inextricably linked with theoretical issues, it is a dynamic practice that is constantly in a process of revision. In this paper I reflect on some of the conceptualisations undergirding the notion of discourse – conceptualisations that have important implications in terms of how the practice of discourse analysis proceeds. I highlight some of the dualisms that may plague discourse analysis, and offer some solutions to these. Finally, I outline the deconstructive discourse analysis that I utilised in my doctoral work. The purpose of the latter is not to provide a recipe of methodology, but to illustrate how elements of various theorists’ work (in this case Foucault, Derrida and Parker) may be profitably drawn together to perform specific discourse analytic work. , Rhodes University
- Full Text:
- Date Issued: 2002
- Authors: Macleod, Catriona I
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6259 , http://hdl.handle.net/10962/d1007877 , http://journals.sagepub.com/doi/abs/10.1177/008124630203200103
- Description: Discourse analysis is increasingly becoming a methodology of preference amongst qualitative researchers. There is a danger, however, of it being viewed as a bounded and uncontested domain of research practice. As discourse analysis is inextricably linked with theoretical issues, it is a dynamic practice that is constantly in a process of revision. In this paper I reflect on some of the conceptualisations undergirding the notion of discourse – conceptualisations that have important implications in terms of how the practice of discourse analysis proceeds. I highlight some of the dualisms that may plague discourse analysis, and offer some solutions to these. Finally, I outline the deconstructive discourse analysis that I utilised in my doctoral work. The purpose of the latter is not to provide a recipe of methodology, but to illustrate how elements of various theorists’ work (in this case Foucault, Derrida and Parker) may be profitably drawn together to perform specific discourse analytic work. , Rhodes University
- Full Text:
- Date Issued: 2002
Genetic characterization of conspecific populations of Tilapia Sparrmanii (A.Smith 1840) in the dolomitic sinkholes and springs of the North-West Province (South Africa), and their comparison to Tilapia Guinasana (Trewavas 1936)
- Authors: Nxomani, Clifford David
- Date: 2002
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4079 , http://hdl.handle.net/10962/d1007452
- Description: This study was undertaken to investigate the genetic relationships of allopatric populations of the cichlid fish, Tilapia sparrmanii (A. Smith 1840) inhabiting the sinkholes and springs of the North West Province, South Africa. It also examined the genetic relationships of T sparrmanii to its polychromatic sister species, Tilapia guinasana (Trewavas 1936) which is endemic to the Guinas sinkhole in Namibia. Finally, the study investigated whether there is a genetic basis for T guinasana's colour polymorphism. The research was prompted by the concern of conservation authorities about the possible loss of unique fauna given the high demand for use of the subterranean waters for agricultural, domestic and industrial purposes. Such demands have the potential to drain these habitats. Further concerns related to habitat destruction and the introduction of alien species in the ecosystems inhabited by both fish species. Three approaches were adopted in attempting to answer the above questions. First was the investigation of Sodium dodecylsulphate (SDS)-Polyacrylamide Gel Electrophoresis (PAGE) of total cellular proteins as a fast and relatively inexpensive indicator of genetic relatedness between the fish populations. Secondly, genetic differentiation between the T sparrmanii populations and its relationship to T guinasana were assayed using restriction endonuclease analysis of Polymerase Chain Reaction (PCR)-amplified regions of the cytochrome b gene and the d-Ioop of mitochondrial DNA, coupled with Temperature Gradient Gel Electrophoresis (TGGE) analysis of the same regions. The third approach involved the use of Random Amplified Polymorphic DNA (RAPD) fingerprinting of the populations ofT sparrmanii as an indicator of genetic differentiation between them. RAPD fingerprinting was further used to investigate the genetic relationships between T sparrmanii and T guinasana and to probe the genetic basis of the polychromatism of the latter. SDS-PAGE did not reveal any genetic differentiation between the T sparrmanii populations, nor could the analysis detect variation within them. It however clearly distinguished at a species level between T sparrmanii and T guinasana as well as between these and other fish species, thus indicating its possible utility as an indicator of genetic relatedness at a species level. Mitochondrial studies employing the Restriction Fragment Length Polymorphism (RFLP) of Polymerase Chain Reaction (PCR)-amplified cytochrome b (1.1 kb) and d-Ioop regions (0.9 kb) with six and five restriction enzymes respectively, failed to reveal genetic differences within and between the allopatric populations. TGGE of500 bp of the d-Ioop and 400 bp of the 12sRNA PCR-amplified fragments did not reveal any differences between the populations of T. sparrmanii, nor did the analysis reveal any differences between T. sparrmanii and T. guinasana. The lack of differentiation between the T. sparrmanii populations by these mitochondrial Dna analysis techniques, despite habitat fragmentation, indicated a recent origin of the populations from a common ancestral population. Failure to distinguish between T. sparrmanii and T. guinasana may be related to the sensitivity of the techniques utilized. RAPD fingerprinting analysis indicated that the populations are genetically differentiated from each other. Using a measure of coefficient of variation, the population with the highest variation was the Wondergat population (13.99%), followed by the Klerkskraal popUlation (8.29%), the Malmani and Marico Oog populations (each with 5.88%) and the least variation (4.95 and 4.83%) was with the Amalinda and Molopo Oog populations respectively. This high degree of intra population similarity points to the fact that this differentiation is still confined within the limits of con specificity. The genetic distances between all of the T. sparrmanii populations across all primers ranged from 0.09 to 0.234 and averaged 0.146, a value that falls in the upper end of conspecific population differentiation. Such results indicate populational sub-division below the species level. RAPD fingerprinting therefore proved more sensitive than protein or mitochondrial studies. The differentiation it detected between the populations is a reflection of their adaptation to local conditions of the unique ecosystems they inhabit. A comparison with a subset of primers between T. guinasana and T. sparrmanii confirmed the separate species status of the former from the latter. The mean genetic distance between the T. sparrmanii populations was 0.136, compared to that between T. sparrmanii and T. guinasana which was found to be 0.374. Statistical analysis of the difference between the mean genetic distances indicated significance with 95% confidence. The polychromatism of T guinasana was investigated to determine whether there were significant differences between its five colour morphs. RAPD fingerprinting indicated with 95% confidence that there were significant differences between the colour forms based on the genetic distances computed between them. These genetic differences appeared to correlate with the observed assortative mating between the colour forms of the species. The manifestation of the polychromatism at sexual maturity in T guinasana probably indicates that colouration plays an important role in the breeding process. The genetic uniqueness shown here between the populations of T sparrmanii and the colour forms of T guinasana indicate for protective measures to be put in place if the genetic resources of the isolated fish populations are to be preserved. These must be coupled with a thorough assessment of the temporal and spatial distribution of genetic variability of the populations as a guide to a long-term management strategy for the fish populations and the ecosystems they inhabit. This study therefore has shown that the allopatric populations of T sparrmanii in the sinkholes and springs of the North-West Province are genetically unique, as well as show that the colour forms of T guinasana are genetically distinct.
- Full Text:
- Date Issued: 2002
- Authors: Nxomani, Clifford David
- Date: 2002
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4079 , http://hdl.handle.net/10962/d1007452
- Description: This study was undertaken to investigate the genetic relationships of allopatric populations of the cichlid fish, Tilapia sparrmanii (A. Smith 1840) inhabiting the sinkholes and springs of the North West Province, South Africa. It also examined the genetic relationships of T sparrmanii to its polychromatic sister species, Tilapia guinasana (Trewavas 1936) which is endemic to the Guinas sinkhole in Namibia. Finally, the study investigated whether there is a genetic basis for T guinasana's colour polymorphism. The research was prompted by the concern of conservation authorities about the possible loss of unique fauna given the high demand for use of the subterranean waters for agricultural, domestic and industrial purposes. Such demands have the potential to drain these habitats. Further concerns related to habitat destruction and the introduction of alien species in the ecosystems inhabited by both fish species. Three approaches were adopted in attempting to answer the above questions. First was the investigation of Sodium dodecylsulphate (SDS)-Polyacrylamide Gel Electrophoresis (PAGE) of total cellular proteins as a fast and relatively inexpensive indicator of genetic relatedness between the fish populations. Secondly, genetic differentiation between the T sparrmanii populations and its relationship to T guinasana were assayed using restriction endonuclease analysis of Polymerase Chain Reaction (PCR)-amplified regions of the cytochrome b gene and the d-Ioop of mitochondrial DNA, coupled with Temperature Gradient Gel Electrophoresis (TGGE) analysis of the same regions. The third approach involved the use of Random Amplified Polymorphic DNA (RAPD) fingerprinting of the populations ofT sparrmanii as an indicator of genetic differentiation between them. RAPD fingerprinting was further used to investigate the genetic relationships between T sparrmanii and T guinasana and to probe the genetic basis of the polychromatism of the latter. SDS-PAGE did not reveal any genetic differentiation between the T sparrmanii populations, nor could the analysis detect variation within them. It however clearly distinguished at a species level between T sparrmanii and T guinasana as well as between these and other fish species, thus indicating its possible utility as an indicator of genetic relatedness at a species level. Mitochondrial studies employing the Restriction Fragment Length Polymorphism (RFLP) of Polymerase Chain Reaction (PCR)-amplified cytochrome b (1.1 kb) and d-Ioop regions (0.9 kb) with six and five restriction enzymes respectively, failed to reveal genetic differences within and between the allopatric populations. TGGE of500 bp of the d-Ioop and 400 bp of the 12sRNA PCR-amplified fragments did not reveal any differences between the populations of T. sparrmanii, nor did the analysis reveal any differences between T. sparrmanii and T. guinasana. The lack of differentiation between the T. sparrmanii populations by these mitochondrial Dna analysis techniques, despite habitat fragmentation, indicated a recent origin of the populations from a common ancestral population. Failure to distinguish between T. sparrmanii and T. guinasana may be related to the sensitivity of the techniques utilized. RAPD fingerprinting analysis indicated that the populations are genetically differentiated from each other. Using a measure of coefficient of variation, the population with the highest variation was the Wondergat population (13.99%), followed by the Klerkskraal popUlation (8.29%), the Malmani and Marico Oog populations (each with 5.88%) and the least variation (4.95 and 4.83%) was with the Amalinda and Molopo Oog populations respectively. This high degree of intra population similarity points to the fact that this differentiation is still confined within the limits of con specificity. The genetic distances between all of the T. sparrmanii populations across all primers ranged from 0.09 to 0.234 and averaged 0.146, a value that falls in the upper end of conspecific population differentiation. Such results indicate populational sub-division below the species level. RAPD fingerprinting therefore proved more sensitive than protein or mitochondrial studies. The differentiation it detected between the populations is a reflection of their adaptation to local conditions of the unique ecosystems they inhabit. A comparison with a subset of primers between T. guinasana and T. sparrmanii confirmed the separate species status of the former from the latter. The mean genetic distance between the T. sparrmanii populations was 0.136, compared to that between T. sparrmanii and T. guinasana which was found to be 0.374. Statistical analysis of the difference between the mean genetic distances indicated significance with 95% confidence. The polychromatism of T guinasana was investigated to determine whether there were significant differences between its five colour morphs. RAPD fingerprinting indicated with 95% confidence that there were significant differences between the colour forms based on the genetic distances computed between them. These genetic differences appeared to correlate with the observed assortative mating between the colour forms of the species. The manifestation of the polychromatism at sexual maturity in T guinasana probably indicates that colouration plays an important role in the breeding process. The genetic uniqueness shown here between the populations of T sparrmanii and the colour forms of T guinasana indicate for protective measures to be put in place if the genetic resources of the isolated fish populations are to be preserved. These must be coupled with a thorough assessment of the temporal and spatial distribution of genetic variability of the populations as a guide to a long-term management strategy for the fish populations and the ecosystems they inhabit. This study therefore has shown that the allopatric populations of T sparrmanii in the sinkholes and springs of the North-West Province are genetically unique, as well as show that the colour forms of T guinasana are genetically distinct.
- Full Text:
- Date Issued: 2002
Effects of substituents on the photosensitizing and electrocatalytic properties of phthalocyanines
- Authors: Maree, Suzanne Elizabeth
- Date: 2002
- Subjects: Phthalocyanines
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4554 , http://hdl.handle.net/10962/d1018247
- Description: In this work a selection of octasubstituted phthalocyaninato Zinc, Ge(IV) and Sn(IV) complexes were synthesized for possible use in photodynamic therapy and their photochemistry, photophysics and electrochemistry studied. Third-generation complexes containing steroids, e.g. cholesterol and estrone, were synthesized to improve tumour selectivity. The zinc phthalocyanine complexes (ZnPc) showed that complexes containing electron-donating groups have higher photostability. Germanium phthalocyanine complexes (GePc) undergo phototransformation rather than direct photobleaching and the tin phthalocyanine complexes (SnPc) undergo photobleaching mediated by photoreduction of the phthalocyanine ring. Singlet oxygen production showed increased in the following order: GePc>SnPc>ZnPc. Triplet lifetimes of the GePc (168-340μs) are very similar to that of the ZnPc (197 - 366μs), but the triplet lifetimes of the SnPc are ten fold shorter (10 - 32μs ). Triplet quantum yields are higher for the GePc (0.20 - 0.50) and SnPc (0.08 - 0.45) than for the ZnPc (0.02 - 0.25). Fluorescence lifetimes of GePc ( 4.0 - 5.1 ns) are significantly longer than that of ZnPc (1.9 - 3.0 ns) and SnPc (0.2 - 0.4 ns). Fluorescence quantum yields decrease in the following order: GePc(0.21-0.31)>ZnPc(0.02-0.21)>SnPc(0.02- 0.06). Ring-substituted cobalt phthalocyanine complexes of the form CoPc(R)4 (R= NH2, N02, C(CH3)3, S03H and COOH) are compared for their catalytic activities towards the oxidation of cysteine. The potential for the electrocatalytic oxidation of cysteine is closely related to the Com/Co11 couple of the CoPc(R)4 complexes in acidic media and to the Con/Co1 couple in basic media. The catalytic current and the oxidation potential for cysteine are dependent on the pH of the solution, the potential becoming less positive and the currents increasing with increase in pH.
- Full Text:
- Date Issued: 2002
- Authors: Maree, Suzanne Elizabeth
- Date: 2002
- Subjects: Phthalocyanines
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4554 , http://hdl.handle.net/10962/d1018247
- Description: In this work a selection of octasubstituted phthalocyaninato Zinc, Ge(IV) and Sn(IV) complexes were synthesized for possible use in photodynamic therapy and their photochemistry, photophysics and electrochemistry studied. Third-generation complexes containing steroids, e.g. cholesterol and estrone, were synthesized to improve tumour selectivity. The zinc phthalocyanine complexes (ZnPc) showed that complexes containing electron-donating groups have higher photostability. Germanium phthalocyanine complexes (GePc) undergo phototransformation rather than direct photobleaching and the tin phthalocyanine complexes (SnPc) undergo photobleaching mediated by photoreduction of the phthalocyanine ring. Singlet oxygen production showed increased in the following order: GePc>SnPc>ZnPc. Triplet lifetimes of the GePc (168-340μs) are very similar to that of the ZnPc (197 - 366μs), but the triplet lifetimes of the SnPc are ten fold shorter (10 - 32μs ). Triplet quantum yields are higher for the GePc (0.20 - 0.50) and SnPc (0.08 - 0.45) than for the ZnPc (0.02 - 0.25). Fluorescence lifetimes of GePc ( 4.0 - 5.1 ns) are significantly longer than that of ZnPc (1.9 - 3.0 ns) and SnPc (0.2 - 0.4 ns). Fluorescence quantum yields decrease in the following order: GePc(0.21-0.31)>ZnPc(0.02-0.21)>SnPc(0.02- 0.06). Ring-substituted cobalt phthalocyanine complexes of the form CoPc(R)4 (R= NH2, N02, C(CH3)3, S03H and COOH) are compared for their catalytic activities towards the oxidation of cysteine. The potential for the electrocatalytic oxidation of cysteine is closely related to the Com/Co11 couple of the CoPc(R)4 complexes in acidic media and to the Con/Co1 couple in basic media. The catalytic current and the oxidation potential for cysteine are dependent on the pH of the solution, the potential becoming less positive and the currents increasing with increase in pH.
- Full Text:
- Date Issued: 2002
Naming students problems: an analysis of language-related discourses at a South African university
- Authors: Boughey, Chrissie
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6086 , http://hdl.handle.net/10962/d1008484 , http://www.tandfonline.com/doi/pdf/10.1080/13562510220144798
- Description: This article examines a number of discourses that construct students 'problems' as they engage with tertiary study at a historically black South African university. These dominant discourses are then linked to Street's 'autonomous' model of literacy and Rampton's 'autonomous' model of applied linguistics in order to interrogate their ideological biases. Implications of the discourses for the provision of epistemological access to tertiary study are then explored. The article ends by indicating how a 'literacy across the curriculum' approach to working with students' difficulties could provide an alternative to current 'remedial' programmes.
- Full Text:
- Date Issued: 2002
- Authors: Boughey, Chrissie
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:6086 , http://hdl.handle.net/10962/d1008484 , http://www.tandfonline.com/doi/pdf/10.1080/13562510220144798
- Description: This article examines a number of discourses that construct students 'problems' as they engage with tertiary study at a historically black South African university. These dominant discourses are then linked to Street's 'autonomous' model of literacy and Rampton's 'autonomous' model of applied linguistics in order to interrogate their ideological biases. Implications of the discourses for the provision of epistemological access to tertiary study are then explored. The article ends by indicating how a 'literacy across the curriculum' approach to working with students' difficulties could provide an alternative to current 'remedial' programmes.
- Full Text:
- Date Issued: 2002
The political ecology of wildlife conservation in Kenya, 1895-1975
- Authors: Matheka, Reuben M
- Date: 2002
- Subjects: Wildlife conservation -- Kenya Environmental policy -- Kenya Wildlife conservation -- Political aspects -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2595 , http://hdl.handle.net/10962/d1007530
- Description: The study examines the development of wildlife conservation policy and practice in Kenya from 1895 to 1975. Started by the colonial state as part of its resource control programme, wildlife conservation in Kenya gradually became an important aspect of the country's economy chiefly because of its significance as the basis of a vibrant tourist industry. The conservation programme was also important to conservationists who viewed Kenya's wildlife as a heritage to humanity. Similarly, local communities, which were affected in various ways by wildlife conservation policies, had their own perceptions of the programme. All this led to the proliferation of groups whose interests were potentially conflicting. Wildlife conservation in Kenya during the period under examination was thus characterised by various struggles between interest groups such as conservationists, the state, and local communities. The struggles centred around such issues as the costs and benefits of conservation and were manifested through anti-conservation activities like the poaching of wild animals by dissatisfied groups. These struggles changed over time in line with social, economic, political, and ecological developments. International events/processes (such as the two world wars, economic booms/depressions, and decolonisation) triggered local processes which influenced conservationism either positively or negatively. Wildlife conservation in Kenya during the period under study was dynamic. The thesis challenges the myth of a monolithic 'colonial' wildlife policy often implied in many studies on the subject. The thesis also lays emphasis on the ecological basis of wildlife conservation while recognising the impact of social, political, and economic developments on the evolution of wildlife conservation policy and practice in Kenya. The country's 'geography' not only provided the foundation for conservation but also influenced the programme over time. Droughts, floods, army worm infestations, and other 'natural' occurrences interacted with social and economic changes, such as population growth and the development of capitalism, to shape conservation policy. The conservation programme was thus influenced by a complex interaction of a variety of factors.
- Full Text:
- Date Issued: 2002
- Authors: Matheka, Reuben M
- Date: 2002
- Subjects: Wildlife conservation -- Kenya Environmental policy -- Kenya Wildlife conservation -- Political aspects -- Kenya
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2595 , http://hdl.handle.net/10962/d1007530
- Description: The study examines the development of wildlife conservation policy and practice in Kenya from 1895 to 1975. Started by the colonial state as part of its resource control programme, wildlife conservation in Kenya gradually became an important aspect of the country's economy chiefly because of its significance as the basis of a vibrant tourist industry. The conservation programme was also important to conservationists who viewed Kenya's wildlife as a heritage to humanity. Similarly, local communities, which were affected in various ways by wildlife conservation policies, had their own perceptions of the programme. All this led to the proliferation of groups whose interests were potentially conflicting. Wildlife conservation in Kenya during the period under examination was thus characterised by various struggles between interest groups such as conservationists, the state, and local communities. The struggles centred around such issues as the costs and benefits of conservation and were manifested through anti-conservation activities like the poaching of wild animals by dissatisfied groups. These struggles changed over time in line with social, economic, political, and ecological developments. International events/processes (such as the two world wars, economic booms/depressions, and decolonisation) triggered local processes which influenced conservationism either positively or negatively. Wildlife conservation in Kenya during the period under study was dynamic. The thesis challenges the myth of a monolithic 'colonial' wildlife policy often implied in many studies on the subject. The thesis also lays emphasis on the ecological basis of wildlife conservation while recognising the impact of social, political, and economic developments on the evolution of wildlife conservation policy and practice in Kenya. The country's 'geography' not only provided the foundation for conservation but also influenced the programme over time. Droughts, floods, army worm infestations, and other 'natural' occurrences interacted with social and economic changes, such as population growth and the development of capitalism, to shape conservation policy. The conservation programme was thus influenced by a complex interaction of a variety of factors.
- Full Text:
- Date Issued: 2002
Bad faith: the psychological life of a satanist who committed murder
- Authors: Du Toit, Jacobus Petrus
- Date: 2002
- Subjects: Murderers -- Psychology , Criminal psychology , Satanism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3152 , http://hdl.handle.net/10962/d1007483 , Murderers -- Psychology , Criminal psychology , Satanism
- Description: Traditional methods of psychological and forensic research fail to adequately provide an account of the psychological meaning that perpetrators of crime derive when appropriating their actions to Satanic involvement. In February 2001, a young man appeared in a South African High Court and testified that he had committed murder as a result of his involvement in Satanism. The aim of this study is to gain a phenomenological understanding of how this man appropriates the act of murder to involvement in Satanism. A review of literature elucidates Satanism as a context for meaning, provide a framework for defining murder as a criminal act, and situate this study in the broader field of phenomenological-existential, psychological research. An emergent design case-study approach was applied to data gathered from a single subject, by means of a three-interview series. An empirical phenomenological methodology was used during the interpretive phase to arrive at both a descriptive account of the subject's phenomenological experience and how the eidetic structure of the experience of Satanism as a context tor meaning emerged. A discussion of the subject's appropriation of murder with Satanism illustrates how the subject imposed a dichotomy of good and bad on his life-world in an attempt to derive meaning from his experience of inadequacy. Involvement with Satanism is meaningful, in that it affords its followers an increased sense of power, a safe environment to explore individuality, shared responsibility associated with exercising free choice, social situatedness and an affirmation of being through an increased awareness of finitude. The research subject experienced committing murder as an act of loyalty to the perceived gains he had been afforded as result of his involvement with Satanism.
- Full Text:
- Date Issued: 2002
- Authors: Du Toit, Jacobus Petrus
- Date: 2002
- Subjects: Murderers -- Psychology , Criminal psychology , Satanism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3152 , http://hdl.handle.net/10962/d1007483 , Murderers -- Psychology , Criminal psychology , Satanism
- Description: Traditional methods of psychological and forensic research fail to adequately provide an account of the psychological meaning that perpetrators of crime derive when appropriating their actions to Satanic involvement. In February 2001, a young man appeared in a South African High Court and testified that he had committed murder as a result of his involvement in Satanism. The aim of this study is to gain a phenomenological understanding of how this man appropriates the act of murder to involvement in Satanism. A review of literature elucidates Satanism as a context for meaning, provide a framework for defining murder as a criminal act, and situate this study in the broader field of phenomenological-existential, psychological research. An emergent design case-study approach was applied to data gathered from a single subject, by means of a three-interview series. An empirical phenomenological methodology was used during the interpretive phase to arrive at both a descriptive account of the subject's phenomenological experience and how the eidetic structure of the experience of Satanism as a context tor meaning emerged. A discussion of the subject's appropriation of murder with Satanism illustrates how the subject imposed a dichotomy of good and bad on his life-world in an attempt to derive meaning from his experience of inadequacy. Involvement with Satanism is meaningful, in that it affords its followers an increased sense of power, a safe environment to explore individuality, shared responsibility associated with exercising free choice, social situatedness and an affirmation of being through an increased awareness of finitude. The research subject experienced committing murder as an act of loyalty to the perceived gains he had been afforded as result of his involvement with Satanism.
- Full Text:
- Date Issued: 2002
Restoring democratic governance in Zimbabwe: a critical investigation of the internet as a possible means of creating new sites of struggle for positive democratic change by Zimbabwean media and activists in Zimbabwe
- Authors: Vennard, Francisca Caroline
- Date: 2002
- Subjects: Zimbabwe -- Politics and government -- 1980- , Internet in publicity , Press and politics -- Zimbabwe , Freedom of the press -- Zimbabwe , Digital media
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2837 , http://hdl.handle.net/10962/d1003047 , Zimbabwe -- Politics and government -- 1980- , Internet in publicity , Press and politics -- Zimbabwe , Freedom of the press -- Zimbabwe , Digital media
- Description: This thesis is a reaction to the state of utter lawlessness and the abuse of human rights by those in power in Zimbabwe over the past two years and it investigates the possibility of restoring democratic governance in that country by increasing the freedom of expression and media freedom, which is considered to be one of the most valuable elements in advancing democratization. Its aim is to establish the Internet as the best means possible to increasing media freedom and creating new ‘sites of struggle’ for activists in a context where the substantive freedom of expression does not exist. This in turn is shown to advance levels of democracy. To this end, the value of the freedom of expression to media freedom and the value of the latter to increasing levels of democracy is developed and the lack of democracy in Zimbabwe at all levels of society is considered. The Internet is seen to increase the freedoms of speech and association in new and interesting ways and it is discussed in various examples in which it has already been instrumental in evading the censorship of the media and increasing the ability of activists to express themselves freely and to organize more efficiently. Finally, the resources that Internet technology makes available to African journalists and activists are considered along with lessons gleaned from international examples of successful Internet use and it is shown to already be of use to Zimbabwean journalists and activists as they create to new cyberspaces in which they can struggle for positive democratic change in Zimbabwe. The Internet is also shown to have tremendous potential for future use in that country.
- Full Text:
- Date Issued: 2002
- Authors: Vennard, Francisca Caroline
- Date: 2002
- Subjects: Zimbabwe -- Politics and government -- 1980- , Internet in publicity , Press and politics -- Zimbabwe , Freedom of the press -- Zimbabwe , Digital media
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2837 , http://hdl.handle.net/10962/d1003047 , Zimbabwe -- Politics and government -- 1980- , Internet in publicity , Press and politics -- Zimbabwe , Freedom of the press -- Zimbabwe , Digital media
- Description: This thesis is a reaction to the state of utter lawlessness and the abuse of human rights by those in power in Zimbabwe over the past two years and it investigates the possibility of restoring democratic governance in that country by increasing the freedom of expression and media freedom, which is considered to be one of the most valuable elements in advancing democratization. Its aim is to establish the Internet as the best means possible to increasing media freedom and creating new ‘sites of struggle’ for activists in a context where the substantive freedom of expression does not exist. This in turn is shown to advance levels of democracy. To this end, the value of the freedom of expression to media freedom and the value of the latter to increasing levels of democracy is developed and the lack of democracy in Zimbabwe at all levels of society is considered. The Internet is seen to increase the freedoms of speech and association in new and interesting ways and it is discussed in various examples in which it has already been instrumental in evading the censorship of the media and increasing the ability of activists to express themselves freely and to organize more efficiently. Finally, the resources that Internet technology makes available to African journalists and activists are considered along with lessons gleaned from international examples of successful Internet use and it is shown to already be of use to Zimbabwean journalists and activists as they create to new cyberspaces in which they can struggle for positive democratic change in Zimbabwe. The Internet is also shown to have tremendous potential for future use in that country.
- Full Text:
- Date Issued: 2002
Can formal language planning link to grassroots cultural initiatives?: an informal investigation
- Authors: Wright, Laurence
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:7041 , http://hdl.handle.net/10962/d1007381
- Description: Formal language planning is inevitably a top-down, highly technical process. Success for such planning would seem to depend on engaging productively with existing or readily developed social motivation within the society. This article reports on an informal investigation into how ordinary language practitioners and cultural workers in South Africa view the possibilities of contributing to the country’s emerging language dispensation, what they regard as their most useful possible contributions, and what they expect from the language planners and ‘government’ in support of South Africa’s Language Policy and Plan.
- Full Text:
- Date Issued: 2002
- Authors: Wright, Laurence
- Date: 2002
- Language: English
- Type: Article
- Identifier: vital:7041 , http://hdl.handle.net/10962/d1007381
- Description: Formal language planning is inevitably a top-down, highly technical process. Success for such planning would seem to depend on engaging productively with existing or readily developed social motivation within the society. This article reports on an informal investigation into how ordinary language practitioners and cultural workers in South Africa view the possibilities of contributing to the country’s emerging language dispensation, what they regard as their most useful possible contributions, and what they expect from the language planners and ‘government’ in support of South Africa’s Language Policy and Plan.
- Full Text:
- Date Issued: 2002