Minor "dings" - major effects? a study into the cognitive effects of mild head injuries in high school rugby
- Authors: Ackermann, Tessa Ruth
- Date: 2000
- Subjects: Rugby football injuries , Head -- Wounds and injuries -- Psychology , Head -- Wounds and injuries -- Complications , Head -- Wounds and injuries -- Patients -- Rehabilitation
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2920 , http://hdl.handle.net/10962/d1002429 , Rugby football injuries , Head -- Wounds and injuries -- Psychology , Head -- Wounds and injuries -- Complications , Head -- Wounds and injuries -- Patients -- Rehabilitation
- Description: The present study is part of a larger and ongoing research initiative investigating the cumulative cognitive effects of mild head injury in rugby union and focused specifically on high school rugby players. A comprehensive battery of neuropsychological tests was administered to top team high school rugby players (n = 47), and a non-contact sport control group of top team high school hockey players (n = 34). Direct comparisons of group mean scores and standard deviations across each neuropsychological test were carried out for the Total Rugby group versus the Total Hockey group as well as for the subgroups Rugby Forwards versus Rugby Backs. A correlational analysis was conducted to ascertain whether a relationship exists between the number of mild head injuries reported by the players and their cognitive test performance. Results of the group comparisons of means and variability on WMS Paired Associate Learning Hard Pairs - Delayed Recall provides tentative indications of the initial stages of diffuse damage associated with mild head injury in the rugby group and provides some evidence for impairment of verbal learning and memory in the Rugby Forwards group. The correlational analysis revealed no significant relationship between number of reported mild head injuries and cognitive performance. The findings and possible latent effects of the multiple mild head injuries reported by the rugby players are discussed in terms of brain reserve capacity theory and suggestions for future research are provided.
- Full Text:
- Date Issued: 2000
- Authors: Ackermann, Tessa Ruth
- Date: 2000
- Subjects: Rugby football injuries , Head -- Wounds and injuries -- Psychology , Head -- Wounds and injuries -- Complications , Head -- Wounds and injuries -- Patients -- Rehabilitation
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2920 , http://hdl.handle.net/10962/d1002429 , Rugby football injuries , Head -- Wounds and injuries -- Psychology , Head -- Wounds and injuries -- Complications , Head -- Wounds and injuries -- Patients -- Rehabilitation
- Description: The present study is part of a larger and ongoing research initiative investigating the cumulative cognitive effects of mild head injury in rugby union and focused specifically on high school rugby players. A comprehensive battery of neuropsychological tests was administered to top team high school rugby players (n = 47), and a non-contact sport control group of top team high school hockey players (n = 34). Direct comparisons of group mean scores and standard deviations across each neuropsychological test were carried out for the Total Rugby group versus the Total Hockey group as well as for the subgroups Rugby Forwards versus Rugby Backs. A correlational analysis was conducted to ascertain whether a relationship exists between the number of mild head injuries reported by the players and their cognitive test performance. Results of the group comparisons of means and variability on WMS Paired Associate Learning Hard Pairs - Delayed Recall provides tentative indications of the initial stages of diffuse damage associated with mild head injury in the rugby group and provides some evidence for impairment of verbal learning and memory in the Rugby Forwards group. The correlational analysis revealed no significant relationship between number of reported mild head injuries and cognitive performance. The findings and possible latent effects of the multiple mild head injuries reported by the rugby players are discussed in terms of brain reserve capacity theory and suggestions for future research are provided.
- Full Text:
- Date Issued: 2000
Peer group supervision as an adjunct to individual supervision: an investigation of models of learning
- Akhurst, Jacqueline Elizabeth
- Authors: Akhurst, Jacqueline Elizabeth
- Date: 2000
- Subjects: Peer-group tutoring of students Psychotherapy -- Study and teaching -- Supervision Psychology -- Supervision of
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2922 , http://hdl.handle.net/10962/d1002431
- Description: Supervision of practice makes an important contribution to the development of psychotherapeutic skills in the training of psychologists (Bernard and Goodyear, 1998). Much research has, until recently, focussed on dyadic, hierarchical models of supervision, even though other forms of supervision have been developed. Peer group supervision has had little attention in the literature, although it is a common form of supervision utilised by psychologists in practice (Lewis, Greenburg and Hatch, 1988). A review of the literature considers the purposes of supervision; elements of dyadic supervision; various forms of group, peer and peer group supervision; and the leaming process in supervision. The development and implementation of a peer supervision group (pSG) of intern psychologists within the training setting of a University is described in this study. The PSG model was developed from the model proposed by Wilbur, Roberts-Wilbur, Morris, Betz and Hart (1991). Transcripts from nine audio-taped PSG sessions were analysed, and a comparison with four audio-taped dyadic supervision sessions was then undertaken. Grounded Theory methodology was employed in the design of the study and analysis of the data. The form and content of the two models of supervision were examined, with particular attention to the perspective of the trainees' learning experiences. The relative merits of both forms of supervision were assessed, and this analysis clearly demonstrates that peer group supervision has the potential to complement dyadic supervision by contributing differing learning experiences. A model of key influences upon, and effects of, participation in the two forms of supervision has been developed. Suggestions are made of ways in which dyadic supervision may be optimised, and recommendations for further development of the PSG emerge. The results were then considered from a neo-Vygotskian perspective. This enabled the findings to be linked to a comprehensive theory of learning, pointing to the key role of speech in thinking, and the contributions of the various forms of dialogue to deepened understandings. The discussion includes: consideration of techniques which enable trainees to obtain assistance from both more experienced practitioners as well as from their peers; an exploration of aspects of subjectivity and intersubjectivity; and contextual influences which have bearing on the study. This study identifies the need for further consideration of the supervision process in South Africa, and makes recommendations for the training of supervisors. The neo-Vygotskian model offers great promise both as a framework for understanding the leaming process in. supervision, and for developing guidelines for enhancing supervisory practice.
- Full Text:
- Date Issued: 2000
- Authors: Akhurst, Jacqueline Elizabeth
- Date: 2000
- Subjects: Peer-group tutoring of students Psychotherapy -- Study and teaching -- Supervision Psychology -- Supervision of
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:2922 , http://hdl.handle.net/10962/d1002431
- Description: Supervision of practice makes an important contribution to the development of psychotherapeutic skills in the training of psychologists (Bernard and Goodyear, 1998). Much research has, until recently, focussed on dyadic, hierarchical models of supervision, even though other forms of supervision have been developed. Peer group supervision has had little attention in the literature, although it is a common form of supervision utilised by psychologists in practice (Lewis, Greenburg and Hatch, 1988). A review of the literature considers the purposes of supervision; elements of dyadic supervision; various forms of group, peer and peer group supervision; and the leaming process in supervision. The development and implementation of a peer supervision group (pSG) of intern psychologists within the training setting of a University is described in this study. The PSG model was developed from the model proposed by Wilbur, Roberts-Wilbur, Morris, Betz and Hart (1991). Transcripts from nine audio-taped PSG sessions were analysed, and a comparison with four audio-taped dyadic supervision sessions was then undertaken. Grounded Theory methodology was employed in the design of the study and analysis of the data. The form and content of the two models of supervision were examined, with particular attention to the perspective of the trainees' learning experiences. The relative merits of both forms of supervision were assessed, and this analysis clearly demonstrates that peer group supervision has the potential to complement dyadic supervision by contributing differing learning experiences. A model of key influences upon, and effects of, participation in the two forms of supervision has been developed. Suggestions are made of ways in which dyadic supervision may be optimised, and recommendations for further development of the PSG emerge. The results were then considered from a neo-Vygotskian perspective. This enabled the findings to be linked to a comprehensive theory of learning, pointing to the key role of speech in thinking, and the contributions of the various forms of dialogue to deepened understandings. The discussion includes: consideration of techniques which enable trainees to obtain assistance from both more experienced practitioners as well as from their peers; an exploration of aspects of subjectivity and intersubjectivity; and contextual influences which have bearing on the study. This study identifies the need for further consideration of the supervision process in South Africa, and makes recommendations for the training of supervisors. The neo-Vygotskian model offers great promise both as a framework for understanding the leaming process in. supervision, and for developing guidelines for enhancing supervisory practice.
- Full Text:
- Date Issued: 2000
Serotonin-melatonin interactions in acetaminophen and N,N-dimethylformamide toxicity
- Anoopkumar-Dukie, Shailendra
- Authors: Anoopkumar-Dukie, Shailendra
- Date: 2000
- Subjects: Serotonin , Acetaminophen , Melatonin
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3898 , http://hdl.handle.net/10962/d1003957 , Serotonin , Acetaminophen , Melatonin
- Description: Acetaminophen and N,N-dimethylformamide (DMF) are compounds which are extremely toxic to the liver. Acetaminophen is a drug which is well known for its analgesic and antipyretic properties. However, the abuse potential of this agent as a non-narcotic analgesic in alcoholics is well known. It is also the leading cause of overdose in England. DMF toxicity results mainly from occupational exposure. At present there are no known reports of an antidote for DMF poisoning, while N-acetylcysteine, the antidote for acetaminophen poisoning, is known to produce adverse effects. The present study evaluates the potential of melatonin as an antidote for acetaminophen and DMF poisoning. This study also investigates the mechanism underlying acetaminophen addiction and abuse. Initial studies involved in vitro techniques in an attempt to remove the complexities of organ interactions. The photodegradation studies, using ultraviolet (UV) light, revealed that melatonin accelerates the rate of acetaminophen degradation in the presence of air, and reduces the rate of degradation in the presence of nitrogen. This study also revealed that melatonin is rapidly degraded in the presence of air, following UV irradiation. The effect of DMF on hydroxyl radical generation was also determined. DMF was shown to act as a free radical scavenger, rather that a generator of free radicals. The in vitro studies were followed by lipid peroxidation determination. DMF (0.4ml/kg and 0.8ml/kg) did not produce any significant increases in lipid peroxidation in the liver. Three different doses of acetaminophen (30mg/kg, 100mg/kg, and 500mg/kg) were administered to rats for seven days. Acetaminophen (500mg/kg) was shown to significantly increase (p<0.05) lipid peroxidation in the liver. Melatonin (2.5mg/kg) was not able to significantly reduce the damage. The lower doses of acetaminophen (30mg/kg and 100mg/kg) did not increase lipid peroxidation. Electron microscopy studies showed that DMF adversely affects the liver, and in particular, the endoplasmic reticulum. Co administration of melatonin (2.5mg/kg) was able to reduce the damage. Further experiments need to be performed before an accurate assessment can be made on the ability of melatonin as an antidote for DMF and acetaminophen poisoning. Several experiments were done in an attempt to uncover the biochemical mechanism underlying acetaminophen addiction and abuse. The first experiment targeted the liver enzyme tryptophan-2,3-dioxygenase (TDO). This enzyme is the major determinant of tryptophan levels in vivo. Acetaminophen administration (100mg/kg for three hours) was shown to significantly inhibit (p<0.05) the activity of TDO, indicating increased peripheral levels of tryptophan. This experiment was followed up with determination of brain serotonin and pineal melatonin. Brain serotonin was determined using the ELISA technique. Melatonin was estimated using this technique as well as with pineal organ culture. Acetaminophen administration (100mg/kg for three hours) significantly increased (p<0.05) brain serotonin levels. Using organ culture where exogenous (3H) tryptophan is metabolised to (3H) melatonin, acetaminophen (100mg/kg for three hours) was shown to significantly increase (p<0.05) pineal melatonin concentrations. However, the ELISA technique did not reveal any changes in endogenous pineal melatonin levels. The final experiment was the determination of urinary 5-hydroxyindole acetic acid (5- HIAA), the major metabolite of serotonin, following acetaminophen administration (100mg/kg for three hours). Acetaminophen was shown to significantly reduce 5-HIAA levels (p<0.05) suggesting reduced catabolism of serotonin. The findings of this study indicate that acetaminophen mimics the actions of an antidepressant. This compelling finding has important clinical implications, and needs to be examined further.
- Full Text:
- Date Issued: 2000
- Authors: Anoopkumar-Dukie, Shailendra
- Date: 2000
- Subjects: Serotonin , Acetaminophen , Melatonin
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3898 , http://hdl.handle.net/10962/d1003957 , Serotonin , Acetaminophen , Melatonin
- Description: Acetaminophen and N,N-dimethylformamide (DMF) are compounds which are extremely toxic to the liver. Acetaminophen is a drug which is well known for its analgesic and antipyretic properties. However, the abuse potential of this agent as a non-narcotic analgesic in alcoholics is well known. It is also the leading cause of overdose in England. DMF toxicity results mainly from occupational exposure. At present there are no known reports of an antidote for DMF poisoning, while N-acetylcysteine, the antidote for acetaminophen poisoning, is known to produce adverse effects. The present study evaluates the potential of melatonin as an antidote for acetaminophen and DMF poisoning. This study also investigates the mechanism underlying acetaminophen addiction and abuse. Initial studies involved in vitro techniques in an attempt to remove the complexities of organ interactions. The photodegradation studies, using ultraviolet (UV) light, revealed that melatonin accelerates the rate of acetaminophen degradation in the presence of air, and reduces the rate of degradation in the presence of nitrogen. This study also revealed that melatonin is rapidly degraded in the presence of air, following UV irradiation. The effect of DMF on hydroxyl radical generation was also determined. DMF was shown to act as a free radical scavenger, rather that a generator of free radicals. The in vitro studies were followed by lipid peroxidation determination. DMF (0.4ml/kg and 0.8ml/kg) did not produce any significant increases in lipid peroxidation in the liver. Three different doses of acetaminophen (30mg/kg, 100mg/kg, and 500mg/kg) were administered to rats for seven days. Acetaminophen (500mg/kg) was shown to significantly increase (p<0.05) lipid peroxidation in the liver. Melatonin (2.5mg/kg) was not able to significantly reduce the damage. The lower doses of acetaminophen (30mg/kg and 100mg/kg) did not increase lipid peroxidation. Electron microscopy studies showed that DMF adversely affects the liver, and in particular, the endoplasmic reticulum. Co administration of melatonin (2.5mg/kg) was able to reduce the damage. Further experiments need to be performed before an accurate assessment can be made on the ability of melatonin as an antidote for DMF and acetaminophen poisoning. Several experiments were done in an attempt to uncover the biochemical mechanism underlying acetaminophen addiction and abuse. The first experiment targeted the liver enzyme tryptophan-2,3-dioxygenase (TDO). This enzyme is the major determinant of tryptophan levels in vivo. Acetaminophen administration (100mg/kg for three hours) was shown to significantly inhibit (p<0.05) the activity of TDO, indicating increased peripheral levels of tryptophan. This experiment was followed up with determination of brain serotonin and pineal melatonin. Brain serotonin was determined using the ELISA technique. Melatonin was estimated using this technique as well as with pineal organ culture. Acetaminophen administration (100mg/kg for three hours) significantly increased (p<0.05) brain serotonin levels. Using organ culture where exogenous (3H) tryptophan is metabolised to (3H) melatonin, acetaminophen (100mg/kg for three hours) was shown to significantly increase (p<0.05) pineal melatonin concentrations. However, the ELISA technique did not reveal any changes in endogenous pineal melatonin levels. The final experiment was the determination of urinary 5-hydroxyindole acetic acid (5- HIAA), the major metabolite of serotonin, following acetaminophen administration (100mg/kg for three hours). Acetaminophen was shown to significantly reduce 5-HIAA levels (p<0.05) suggesting reduced catabolism of serotonin. The findings of this study indicate that acetaminophen mimics the actions of an antidepressant. This compelling finding has important clinical implications, and needs to be examined further.
- Full Text:
- Date Issued: 2000
Stability of prochlorperazine in solution and in the solid-state
- Authors: Antunes, Edith Martins
- Date: 2000
- Subjects: Phenothiazine
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4536 , http://hdl.handle.net/10962/d1016399
- Description: Prochlorperazine, a member of the piperazine subclass of phenothiazines, widely used as an anti-emetic, is susceptible to oxidation to sulfoxides. These are main metabolites and degradants of all phenothiazines which are found to be inactive at the dopamine receptors. Prochlorperazine causes photosensitivity effects in patients attributed to dechlorination at C2 with the release of HCI (Huang and Sands, 1967; Nejmeh and Pilpel, 1978; Moore and Tamat, 1980). The aim of this study is to investigate the thermal and photostability of prochlorperazine edisylate and mesylate salts in the solid state and in solution. Prochlorperazine is available as a fine chemical and in a variety of dosage forms, including injectables and tablets. According to ICH guidelines, any degradants greater than 0.1 % are required to be isolated and identified. In order to assess the photostability of the two salts, an HPLC method was developed and validated for linearity, accuracy and precision, selectivity, limit of detection, quantitation and ruggedness. Sulfoxides were synthesised for use as standards in the rate studies according to the well-known hydrogen peroxide method (Owens et al., 1989). The rate of prochlorperazine degradation in solution under various light sources (254 nm UV light, diffuse light and sunlight) was studied. The light sources used abovF were quantified using potassium ferrioxalate as a chemical actinometer). The photodegradation rate was found to be greater in ampoules sealed under nitrogen than air, but the thermal degradation was faster in ampoules sealed with air than those purged with nitrogen. Amber ampoules retarded the rate of degradation under all photolytic conditions. This is a vital consideration for the packaging and storage of prochlorperazine in injectables. Degradation was found to occur mainly by first-order kinetics and the degradation rate decreased in the following order: sunlight » UV light 254 nm > fluorescent I diffuse light. Solid state samples, however, were found to be relatively stable to the various light / heat conditions over a 6 month period when compared to prochlorperazine solutions, but still considerably unstable. Thus both storage and packaging is a vital consideration for prochlorperazine injectables. The thermal behaviour of mixtures of prochlorperazine with standard excipients, was assessed for potential interactions, using differential scanning calorimetry. For most of the excipients (magnesium stearate, stearic acid, Explotab®, AC-Di-Sol®, Encompress® and Ludipress®, lactose and Starch 1500®) disappearance or broadening of the melting endotherm of the drug indicated interactions. Lubritab®, however, was the only 'inert' excipient tested. Liquid chromatography - mass spectrometry (LC-MS) was used to determine the nature of the degradation products. The major degradation pathways included dechlorination and demethylation of the parent drug, as well as sulfoxidation and Noxidation. Prochlorperazine underwent dechlorination and sulfoxidation with subsequent photosubstitution to yield the 2-hydroxy derivative. The solid state photostudies showed the formation of dealkylated, oxidised and hydroxylated products, sulfoxides and dimers. Since N-demethylation, N-oxidation, sulfoxidation and aromatic hydroxylation are reported to occur in the in vitro metabolism of perazine derivatives, it does appear that there is some relationship between metabolites and photoproducts (Breyer, 1974). This study has been successful in providing understanding of the photolytic and thermal degradation pathways of prochlorperazine.
- Full Text:
- Date Issued: 2000
- Authors: Antunes, Edith Martins
- Date: 2000
- Subjects: Phenothiazine
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4536 , http://hdl.handle.net/10962/d1016399
- Description: Prochlorperazine, a member of the piperazine subclass of phenothiazines, widely used as an anti-emetic, is susceptible to oxidation to sulfoxides. These are main metabolites and degradants of all phenothiazines which are found to be inactive at the dopamine receptors. Prochlorperazine causes photosensitivity effects in patients attributed to dechlorination at C2 with the release of HCI (Huang and Sands, 1967; Nejmeh and Pilpel, 1978; Moore and Tamat, 1980). The aim of this study is to investigate the thermal and photostability of prochlorperazine edisylate and mesylate salts in the solid state and in solution. Prochlorperazine is available as a fine chemical and in a variety of dosage forms, including injectables and tablets. According to ICH guidelines, any degradants greater than 0.1 % are required to be isolated and identified. In order to assess the photostability of the two salts, an HPLC method was developed and validated for linearity, accuracy and precision, selectivity, limit of detection, quantitation and ruggedness. Sulfoxides were synthesised for use as standards in the rate studies according to the well-known hydrogen peroxide method (Owens et al., 1989). The rate of prochlorperazine degradation in solution under various light sources (254 nm UV light, diffuse light and sunlight) was studied. The light sources used abovF were quantified using potassium ferrioxalate as a chemical actinometer). The photodegradation rate was found to be greater in ampoules sealed under nitrogen than air, but the thermal degradation was faster in ampoules sealed with air than those purged with nitrogen. Amber ampoules retarded the rate of degradation under all photolytic conditions. This is a vital consideration for the packaging and storage of prochlorperazine in injectables. Degradation was found to occur mainly by first-order kinetics and the degradation rate decreased in the following order: sunlight » UV light 254 nm > fluorescent I diffuse light. Solid state samples, however, were found to be relatively stable to the various light / heat conditions over a 6 month period when compared to prochlorperazine solutions, but still considerably unstable. Thus both storage and packaging is a vital consideration for prochlorperazine injectables. The thermal behaviour of mixtures of prochlorperazine with standard excipients, was assessed for potential interactions, using differential scanning calorimetry. For most of the excipients (magnesium stearate, stearic acid, Explotab®, AC-Di-Sol®, Encompress® and Ludipress®, lactose and Starch 1500®) disappearance or broadening of the melting endotherm of the drug indicated interactions. Lubritab®, however, was the only 'inert' excipient tested. Liquid chromatography - mass spectrometry (LC-MS) was used to determine the nature of the degradation products. The major degradation pathways included dechlorination and demethylation of the parent drug, as well as sulfoxidation and Noxidation. Prochlorperazine underwent dechlorination and sulfoxidation with subsequent photosubstitution to yield the 2-hydroxy derivative. The solid state photostudies showed the formation of dealkylated, oxidised and hydroxylated products, sulfoxides and dimers. Since N-demethylation, N-oxidation, sulfoxidation and aromatic hydroxylation are reported to occur in the in vitro metabolism of perazine derivatives, it does appear that there is some relationship between metabolites and photoproducts (Breyer, 1974). This study has been successful in providing understanding of the photolytic and thermal degradation pathways of prochlorperazine.
- Full Text:
- Date Issued: 2000
The Raven's Coloured Progressive Matrices Test: a pilot study for the establishment of normative data for Xhosa-speaking primary school pupils in the Grahamstown region
- Authors: Bass, Natalie Tanyia
- Date: 2000
- Subjects: Raven's Progressive Matrices , Students -- South Africa -- Psychology , Educational tests and measurements -- South Africa , Intelligence levels -- South Africa , Students -- Psychology
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2930 , http://hdl.handle.net/10962/d1002439 , Raven's Progressive Matrices , Students -- South Africa -- Psychology , Educational tests and measurements -- South Africa , Intelligence levels -- South Africa , Students -- Psychology
- Description: The Raven’s Coloured Progressive Matrices (CPM) test is used extensively across a wide variety of settings in South Africa, however more appropriate local normative data has yet to be established. The CPM is internationally recognised as a culture-fair test of nonverbal intelligence, designed for use with children between the ages of 5½ and 11½. This pilot study thus sought to establish normative data for this instrument for a population of Xhosa-speaking Primary School children in the peri-urban township area in the Grahamstown region. The booklet version of the test was used and it was administered in group format and according to an alternate method of test administration (using Xhosa instructions) developed by Vass in 1992. The final normative sample consisted of 197 male and 182 female Xhosa-speaking children in Grades Two to Seven (N=379). The results showed (1) a significant effect of age on test scores, where scores increased with age as expected; (2) a consistent tendency for males to outperform females was also noted, however small sample sizes precluded any categorical claims to this effect; (3) no significant effect of education on test scores was observed and finally; (4) and finally, it appeared that the norms generated for this study revealed a tendency to be lower than those obtained by Raven, Court and Raven (1990) during the standardisation of this instrument in the United Kingdom and America. The study concluded that (1) there is an urgent need for more appropriate South African normative data for this test; and (2) that when assessing African children from disadvantaged backgrounds, further research into the effects of cultural and socio-economic factors and gender on non-verbal intelligence (and on performance on this test in particular) is required.
- Full Text:
- Date Issued: 2000
- Authors: Bass, Natalie Tanyia
- Date: 2000
- Subjects: Raven's Progressive Matrices , Students -- South Africa -- Psychology , Educational tests and measurements -- South Africa , Intelligence levels -- South Africa , Students -- Psychology
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2930 , http://hdl.handle.net/10962/d1002439 , Raven's Progressive Matrices , Students -- South Africa -- Psychology , Educational tests and measurements -- South Africa , Intelligence levels -- South Africa , Students -- Psychology
- Description: The Raven’s Coloured Progressive Matrices (CPM) test is used extensively across a wide variety of settings in South Africa, however more appropriate local normative data has yet to be established. The CPM is internationally recognised as a culture-fair test of nonverbal intelligence, designed for use with children between the ages of 5½ and 11½. This pilot study thus sought to establish normative data for this instrument for a population of Xhosa-speaking Primary School children in the peri-urban township area in the Grahamstown region. The booklet version of the test was used and it was administered in group format and according to an alternate method of test administration (using Xhosa instructions) developed by Vass in 1992. The final normative sample consisted of 197 male and 182 female Xhosa-speaking children in Grades Two to Seven (N=379). The results showed (1) a significant effect of age on test scores, where scores increased with age as expected; (2) a consistent tendency for males to outperform females was also noted, however small sample sizes precluded any categorical claims to this effect; (3) no significant effect of education on test scores was observed and finally; (4) and finally, it appeared that the norms generated for this study revealed a tendency to be lower than those obtained by Raven, Court and Raven (1990) during the standardisation of this instrument in the United Kingdom and America. The study concluded that (1) there is an urgent need for more appropriate South African normative data for this test; and (2) that when assessing African children from disadvantaged backgrounds, further research into the effects of cultural and socio-economic factors and gender on non-verbal intelligence (and on performance on this test in particular) is required.
- Full Text:
- Date Issued: 2000
An evaluation of IMF structural adjustment programmes : lessons for South Africa
- Authors: Berolsky, Nuno Goncalo
- Date: 2000
- Subjects: International Monetary Fund , International Monetary Fund -- Developing countries , Structural adjustment (Economic policy) -- Developing countries , South Africa -- Economic policy
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:935 , http://hdl.handle.net/10962/d1002668 , International Monetary Fund , International Monetary Fund -- Developing countries , Structural adjustment (Economic policy) -- Developing countries , South Africa -- Economic policy
- Description: The mixed results of International Monetary Fund structural adjustment programmes in less developed countries are a major motivation for this research. Explanations must be advanced as to what may inhibit the success of such programmes. South Africa has often found itself in a precarious position- with a deteriorating balance of payments, a position similar to other countries that have accepted IMF loans. Furthermore, South Africa undertook an IMF loan in 1993. Financial support from the IMF incorporates structural adjustment programmes. These may include measures such as tighter monetary policy, reduction in the budget deficit, exchange rate devaluation and ceilings on domestic credit with increased interest rates (Ferguson, 1988). These policies illustrate the principle of ‘conditionality,’ whereby access to further loans is conditional on certain criteria being met, such as reduced budget deficits and inflation rates. The principle of conditionality has met with a great deal of criticism. Bacha (1987) and Dell (1982) argue that these aggregate demand-reducing conditions more often than not stagnate domestic economies, worsening the balance of payment and result in programme breakdowns. Essentially, they refer to the IMF conditions as ‘unrealistic.’ The IMF denies this, arguing that shortfalls are mainly due to a lack of political commitment to carry out its conditions (Winters, 1994). This issue of conditionality will be examined in detail, using three specific case studies. The aim of this study is to examine the characteristics of Brazil, Mexico and Zambia to see whether or not the IMF programmes were successful. Guidelines will be established for South African policy from these case studies. South Africa is trying to adjust to the competitiveness of the international economy. At the same time, the need for reconstruction and development exerts increasing pressures on the balance of payments. Guidelines are established for a successful economic adjustment for South Africa. The research concludes that South Africa is certainly in line for a successful transformation. The rigidities are not as extensive as has been the case in Brazil and Zambia. Institutionally, South Africa is sound. However there are still challenges in this area, such as export diversification and economic stability to attract foreign investment.
- Full Text:
- Date Issued: 2000
- Authors: Berolsky, Nuno Goncalo
- Date: 2000
- Subjects: International Monetary Fund , International Monetary Fund -- Developing countries , Structural adjustment (Economic policy) -- Developing countries , South Africa -- Economic policy
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:935 , http://hdl.handle.net/10962/d1002668 , International Monetary Fund , International Monetary Fund -- Developing countries , Structural adjustment (Economic policy) -- Developing countries , South Africa -- Economic policy
- Description: The mixed results of International Monetary Fund structural adjustment programmes in less developed countries are a major motivation for this research. Explanations must be advanced as to what may inhibit the success of such programmes. South Africa has often found itself in a precarious position- with a deteriorating balance of payments, a position similar to other countries that have accepted IMF loans. Furthermore, South Africa undertook an IMF loan in 1993. Financial support from the IMF incorporates structural adjustment programmes. These may include measures such as tighter monetary policy, reduction in the budget deficit, exchange rate devaluation and ceilings on domestic credit with increased interest rates (Ferguson, 1988). These policies illustrate the principle of ‘conditionality,’ whereby access to further loans is conditional on certain criteria being met, such as reduced budget deficits and inflation rates. The principle of conditionality has met with a great deal of criticism. Bacha (1987) and Dell (1982) argue that these aggregate demand-reducing conditions more often than not stagnate domestic economies, worsening the balance of payment and result in programme breakdowns. Essentially, they refer to the IMF conditions as ‘unrealistic.’ The IMF denies this, arguing that shortfalls are mainly due to a lack of political commitment to carry out its conditions (Winters, 1994). This issue of conditionality will be examined in detail, using three specific case studies. The aim of this study is to examine the characteristics of Brazil, Mexico and Zambia to see whether or not the IMF programmes were successful. Guidelines will be established for South African policy from these case studies. South Africa is trying to adjust to the competitiveness of the international economy. At the same time, the need for reconstruction and development exerts increasing pressures on the balance of payments. Guidelines are established for a successful economic adjustment for South Africa. The research concludes that South Africa is certainly in line for a successful transformation. The rigidities are not as extensive as has been the case in Brazil and Zambia. Institutionally, South Africa is sound. However there are still challenges in this area, such as export diversification and economic stability to attract foreign investment.
- Full Text:
- Date Issued: 2000
Structural and synthetic investigations of South African marine natural products
- Authors: Beukes, Denzil Ronwynne
- Date: 2000
- Subjects: Natural products -- South Africa Marine invertebrates -- South Africa Marine metabolites -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4350 , http://hdl.handle.net/10962/d1005015
- Description: A chemical investigation of six different marine invertebrates, collected along the South African coastline, resulted in the isolation and structural elucidation of fifteen previously undescribed secondary metabolites along with seven known compounds. The structures of the new metabolites were determined by a combination of spectroscopic and chemical methods. The endemic false limpet Siphonaria capensis was shown to contain two unusual polypropionate metabolites capensinone (162) and capensifuranone (163) as well as 2,4,6,8-tetramethyl-2-undecenoic acid (164) and the known polypropionates (E)- and (Z)siphonarienfuranone (149 and 161). Capensinone is the first example of a marine polypropionate containing a cyc1opentenone moiety. An investigation of the endemic South African soft coral Pieterfaurea unilobata yielded six new, highly oxygenated, pregnadiene sterols (180-185) and the known metabolite (169). Compounds 180-185 are the first pregnadienes obtained from the marine environment containing a C-7 substituent. An alternative procedure for the quick assignment of the absolute configuration at C-3 in this series of compounds was proposed. A companson of the pyrroloiminoquinone alkaloids of three undescribed l'}trunculid sponges resulted in the isolation of 3-dih¥drodiscorhabdin C (243), 3-dihydrodiscorhabdin B (244), discorhabdin H (197) and the previously reported alkaloids discorhabdin A (189) and discorhabdin D (192). While all three sponges were found to be morphologically different they all contained discorhabdin A as the major metabolite and discorhabdin H as one of their minor metabolites. It was found that a feature common to most of the South African latrunculid sponges is the reduction of the C-3 carbonyl gr,o up in some of the minor metabolites. The indole alkaloids, dilemmaones A-C (261-263), containing an unusual cyc1opentanone-indole skeleton, were isolated in trace amounts by bioassay guided fractionation of an extract obtained from a mixed collection of sponges collected near Cape Town. In an attempt to acquire more of these novel compounds for further investigation of their biological activity, several synthetic strategies towards their total synthesis were explored. A key feature of these approaches was the exploitation of the regioselective Gassman's artha-alkylation procedure for the introduction of an aromatic methyl substituent.
- Full Text:
- Date Issued: 2000
- Authors: Beukes, Denzil Ronwynne
- Date: 2000
- Subjects: Natural products -- South Africa Marine invertebrates -- South Africa Marine metabolites -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4350 , http://hdl.handle.net/10962/d1005015
- Description: A chemical investigation of six different marine invertebrates, collected along the South African coastline, resulted in the isolation and structural elucidation of fifteen previously undescribed secondary metabolites along with seven known compounds. The structures of the new metabolites were determined by a combination of spectroscopic and chemical methods. The endemic false limpet Siphonaria capensis was shown to contain two unusual polypropionate metabolites capensinone (162) and capensifuranone (163) as well as 2,4,6,8-tetramethyl-2-undecenoic acid (164) and the known polypropionates (E)- and (Z)siphonarienfuranone (149 and 161). Capensinone is the first example of a marine polypropionate containing a cyc1opentenone moiety. An investigation of the endemic South African soft coral Pieterfaurea unilobata yielded six new, highly oxygenated, pregnadiene sterols (180-185) and the known metabolite (169). Compounds 180-185 are the first pregnadienes obtained from the marine environment containing a C-7 substituent. An alternative procedure for the quick assignment of the absolute configuration at C-3 in this series of compounds was proposed. A companson of the pyrroloiminoquinone alkaloids of three undescribed l'}trunculid sponges resulted in the isolation of 3-dih¥drodiscorhabdin C (243), 3-dihydrodiscorhabdin B (244), discorhabdin H (197) and the previously reported alkaloids discorhabdin A (189) and discorhabdin D (192). While all three sponges were found to be morphologically different they all contained discorhabdin A as the major metabolite and discorhabdin H as one of their minor metabolites. It was found that a feature common to most of the South African latrunculid sponges is the reduction of the C-3 carbonyl gr,o up in some of the minor metabolites. The indole alkaloids, dilemmaones A-C (261-263), containing an unusual cyc1opentanone-indole skeleton, were isolated in trace amounts by bioassay guided fractionation of an extract obtained from a mixed collection of sponges collected near Cape Town. In an attempt to acquire more of these novel compounds for further investigation of their biological activity, several synthetic strategies towards their total synthesis were explored. A key feature of these approaches was the exploitation of the regioselective Gassman's artha-alkylation procedure for the introduction of an aromatic methyl substituent.
- Full Text:
- Date Issued: 2000
Studies of the population structure and generic diversity of domesticated and "wild" ostriches (Struthio camelus)
- Bezuidenhout, Cornelius Carlos
- Authors: Bezuidenhout, Cornelius Carlos
- Date: 2000
- Subjects: Ostriches Ostriches -- Genetics Ostriches -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3907 , http://hdl.handle.net/10962/d1003966
- Description: DNA sequencing and restriction fragment length polymorphism analysis (RFLP) of polymerase chain reaction (PCR) amplified mitochondrial DNA fragments, and random amplified polymorphic DNA sequence (RAPD) analysis were techniques evaluated in this study for applicability in the investigation various aspects of genetic diversity within the ostrich (Struthio camelus). The genetic aspects that were investigated were (i) relationships between ostrich subspecies, (ii) genetic variability between and within domesticated populations of southern African ostriches (Struthio camelus australis), (iii) linking egg production in domesticated ostriches to RAPD profiles, and (iv) determining the zygosity of twin ostriches. In the first part of this study DNA sequencing and the polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) methods were evaluated for resolving genetic differences in the small mtDNA fragments ofthe ostrich. DNA sequencing ofPCR amplified 450 bp 12S rRNA gene fragments of representatives from the southern African population ostrich (S.c. australis) did not reveal any differences between the populatiohs from different geographical areas, representing ostrich lineages with different breeding histories. The PCRRFLP analysis ofmtDNA fragments (450 bp 12S rRNA gene fragment and 550 bp D-loop region) also did not reveal any genetic variability between the domesticated s.,c. australis populations included in this study. PCR-RFLP analysis of a 450 bp 12S rRNA gene fragment, however, showed differences between the subspecies s.c. australis and s.c. molybdophanes. The proportion of shared fragments (F) between these two subspecies was 0.286 and nucleotide sequence divergence estimated at 8.9 %. Divergence time between these two subspecies was estimated at 4.5 million years ago. The data presented from this study are comparable to the data from a previous study in which the entire mitochondrial genome and a larger number of restriction enzymes were used. The PCR-RFLP method thus demonstrated its usefulness for genetic studies of ostriches at thesubspecies level. The sequences used in this study could not reveal any markers that were useful for genetic studies of ostriches at the population level. In the second part of the study the RAPD method was evaluated for application in the genetic studies of ostriches. RAPD profiles, based on three RAPD primers, revealed differences between three subspecies of ostriches and indicated relationships between these subspecies that are consistent with observations from other studies. The numerical analysis of pooled and individual primer data demonstrated that the subspecies s.c. australis is more closely related to s.c. massaicus than to s.c. molybdophanes. RAPD marker differences between s.c. molybdophanes on the one hand, and s.c. massaicus and s.c. australis on the other is also consistent with observations from studies that proposed separate specie~ status for s.c. molybdophanes. RAPD analysis by five primers revealed geographic variation between s.c. australis populations. The clustering patterns observed in the dendrograms and Neighbour Joining Trees generated by computer programs showed trends of separating ostric1;t populations into geographical groups, possibly reflecting their different breeding histories. In the RAPD profiles of the inbred population, band-sharing was generally greater than in the outbreeding group. RAPD analysis thus showed that it may be a useful method in the population studies of domesticated S. c. australis. RAPDs also generated data that grouped ostriches according to trends in egg production capabilities. Analysis ofRAPD profiles by computer software showed a Neighbour Joining Tree and a dendrogram that predominantly grouped ostriches into clusters associated with either good or poor egg production. Evidence supporting the suitability of RAPDs as a tool in breeding programmes of ostriches was thus provided by this study. RAPDs also provided data, demonstrating that two sets of ostrich twins were non-identical twins. It was demonstrated by this study that RAPDs analysis may be a useful technique for applying to (1) systematic (2) population (3) breeding and (4) twin studies of ostriches (Struthio camelus).
- Full Text:
- Date Issued: 2000
- Authors: Bezuidenhout, Cornelius Carlos
- Date: 2000
- Subjects: Ostriches Ostriches -- Genetics Ostriches -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3907 , http://hdl.handle.net/10962/d1003966
- Description: DNA sequencing and restriction fragment length polymorphism analysis (RFLP) of polymerase chain reaction (PCR) amplified mitochondrial DNA fragments, and random amplified polymorphic DNA sequence (RAPD) analysis were techniques evaluated in this study for applicability in the investigation various aspects of genetic diversity within the ostrich (Struthio camelus). The genetic aspects that were investigated were (i) relationships between ostrich subspecies, (ii) genetic variability between and within domesticated populations of southern African ostriches (Struthio camelus australis), (iii) linking egg production in domesticated ostriches to RAPD profiles, and (iv) determining the zygosity of twin ostriches. In the first part of this study DNA sequencing and the polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) methods were evaluated for resolving genetic differences in the small mtDNA fragments ofthe ostrich. DNA sequencing ofPCR amplified 450 bp 12S rRNA gene fragments of representatives from the southern African population ostrich (S.c. australis) did not reveal any differences between the populatiohs from different geographical areas, representing ostrich lineages with different breeding histories. The PCRRFLP analysis ofmtDNA fragments (450 bp 12S rRNA gene fragment and 550 bp D-loop region) also did not reveal any genetic variability between the domesticated s.,c. australis populations included in this study. PCR-RFLP analysis of a 450 bp 12S rRNA gene fragment, however, showed differences between the subspecies s.c. australis and s.c. molybdophanes. The proportion of shared fragments (F) between these two subspecies was 0.286 and nucleotide sequence divergence estimated at 8.9 %. Divergence time between these two subspecies was estimated at 4.5 million years ago. The data presented from this study are comparable to the data from a previous study in which the entire mitochondrial genome and a larger number of restriction enzymes were used. The PCR-RFLP method thus demonstrated its usefulness for genetic studies of ostriches at thesubspecies level. The sequences used in this study could not reveal any markers that were useful for genetic studies of ostriches at the population level. In the second part of the study the RAPD method was evaluated for application in the genetic studies of ostriches. RAPD profiles, based on three RAPD primers, revealed differences between three subspecies of ostriches and indicated relationships between these subspecies that are consistent with observations from other studies. The numerical analysis of pooled and individual primer data demonstrated that the subspecies s.c. australis is more closely related to s.c. massaicus than to s.c. molybdophanes. RAPD marker differences between s.c. molybdophanes on the one hand, and s.c. massaicus and s.c. australis on the other is also consistent with observations from studies that proposed separate specie~ status for s.c. molybdophanes. RAPD analysis by five primers revealed geographic variation between s.c. australis populations. The clustering patterns observed in the dendrograms and Neighbour Joining Trees generated by computer programs showed trends of separating ostric1;t populations into geographical groups, possibly reflecting their different breeding histories. In the RAPD profiles of the inbred population, band-sharing was generally greater than in the outbreeding group. RAPD analysis thus showed that it may be a useful method in the population studies of domesticated S. c. australis. RAPDs also generated data that grouped ostriches according to trends in egg production capabilities. Analysis ofRAPD profiles by computer software showed a Neighbour Joining Tree and a dendrogram that predominantly grouped ostriches into clusters associated with either good or poor egg production. Evidence supporting the suitability of RAPDs as a tool in breeding programmes of ostriches was thus provided by this study. RAPDs also provided data, demonstrating that two sets of ostrich twins were non-identical twins. It was demonstrated by this study that RAPDs analysis may be a useful technique for applying to (1) systematic (2) population (3) breeding and (4) twin studies of ostriches (Struthio camelus).
- Full Text:
- Date Issued: 2000
An evaluation of recirculating artificial stream designs for acute toxicity testing using two South African Ephemeroptera species exposed to sodium sulphate
- Authors: Binder, Markus
- Date: 2000
- Subjects: Water -- Pollution -- Toxicology , Toxicology -- Research , Aquatic organisms -- Effect of water pollution on , Sodium sulfate , Mayflies
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5690 , http://hdl.handle.net/10962/d1005376 , Water -- Pollution -- Toxicology , Toxicology -- Research , Aquatic organisms -- Effect of water pollution on , Sodium sulfate , Mayflies
- Description: Three artificial stream designs, termed Large Artificial Stream Units (LASUs), Raceways, and Channels, at two major scales (1700 L, 12.5 L and 20 L recirculated volume) were developed at the Institute for Water Research, Rhodes University, Grahamstown, in order to explore the possibilities of using indigenous rheophilic macroinvertebrates in routine toxicity tests. This study compared these systems, using 96h-EC50 values from sodium sulphate toxicity tests as the experimental response. Two local Ephemeroptera (Leptophlebiidae: Adenophlebia auriculata Eaton, and Baetidae: Afroptilum sudafricanum Lestage) were evaluated for their suitability in routine toxicity tests; and the possible effects of elevated salinity levels in South African rivers on the test species were assessed. Two sets of experiments with each mayfly species were conducted, following an unreplicated regression design. Dechlorinated tap water was used as the water source. Experiments in the Channels were repeated to determine experimental variability. Results were compared statistically by testing for overlap of 95% confidence limits (95%Cls) of EC50 values. The differences between A. auriculata EC50 values in the different systems were statistically significant (no overlap of 95%CLs), but they were not more variable than has been considered normal for biological systems (Coefficient of variation 20.1 %; ratio of greatest EC50 / smallest EC50 1.63). The differences were not related to the scale or the average current velocity characteristic of each stream design (average current velocity LASUs - Raceways - Channels 0.090 - 0.083 - 0.038 m/s). The Channels proved to be most efficient with regard to practical performance as they are portable and easily transportable, user-friendly, reliable, splash-free, cost effective to construct, and can easily be adapted to specific requirements. These systems are therefore recommended for regular use. The suitability of the two mayfly species for routine toxicity testing was evaluated. A. auriculata EC50 values showed a significant negative correlation with the corresponding average body-size (range 1476 - 1610 μm, mean 1555 μm). The different average body-sizes probably reflected the abundance of a certain size range present in the Palmiet River at the time of collection. Both species reacted similarly to Na₂S0₄ (similar slopes of the toxicity curves), identifying this salt as a slow acting toxicant. A. sudafricanum populations were more sensitive to Na₂S0₄ (EC50 3.404 g/L) than A. auriculata (EC50 8.090 g/L), probably because of its smaller body-size (mean 709 μm) and a lack of extremely tolerant individuals. In comparison to other freshwater macro invertebrates, including the standard toxicity test organism Daphnia spp., both mayfly species seemed to be moderately tolerant of Na₂S0₄; therefore there was no particular advantage to using these indigenous taxa rather than Daphnia spp. An assessment of the effects of elevated salinity/TDS levels on the test taxa yielded preliminary insights. A NaCI-EC50 for A. sudafricanum could be extrapolated and suggested a higher sensitivity to Na₂S0₄ than to NaCl. When Na₂S0₄ EC50 values of both species were compared to selected TDS levels of South African rivers, 4. auriculata would mostly not be affected, but A. sudafricanum might occasionally suffer from sub-lethal effects, depending on the sulphate proportion of the TDS. The South African guideline for TDS seemed to protect both species sufficiently.
- Full Text:
- Date Issued: 2000
- Authors: Binder, Markus
- Date: 2000
- Subjects: Water -- Pollution -- Toxicology , Toxicology -- Research , Aquatic organisms -- Effect of water pollution on , Sodium sulfate , Mayflies
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5690 , http://hdl.handle.net/10962/d1005376 , Water -- Pollution -- Toxicology , Toxicology -- Research , Aquatic organisms -- Effect of water pollution on , Sodium sulfate , Mayflies
- Description: Three artificial stream designs, termed Large Artificial Stream Units (LASUs), Raceways, and Channels, at two major scales (1700 L, 12.5 L and 20 L recirculated volume) were developed at the Institute for Water Research, Rhodes University, Grahamstown, in order to explore the possibilities of using indigenous rheophilic macroinvertebrates in routine toxicity tests. This study compared these systems, using 96h-EC50 values from sodium sulphate toxicity tests as the experimental response. Two local Ephemeroptera (Leptophlebiidae: Adenophlebia auriculata Eaton, and Baetidae: Afroptilum sudafricanum Lestage) were evaluated for their suitability in routine toxicity tests; and the possible effects of elevated salinity levels in South African rivers on the test species were assessed. Two sets of experiments with each mayfly species were conducted, following an unreplicated regression design. Dechlorinated tap water was used as the water source. Experiments in the Channels were repeated to determine experimental variability. Results were compared statistically by testing for overlap of 95% confidence limits (95%Cls) of EC50 values. The differences between A. auriculata EC50 values in the different systems were statistically significant (no overlap of 95%CLs), but they were not more variable than has been considered normal for biological systems (Coefficient of variation 20.1 %; ratio of greatest EC50 / smallest EC50 1.63). The differences were not related to the scale or the average current velocity characteristic of each stream design (average current velocity LASUs - Raceways - Channels 0.090 - 0.083 - 0.038 m/s). The Channels proved to be most efficient with regard to practical performance as they are portable and easily transportable, user-friendly, reliable, splash-free, cost effective to construct, and can easily be adapted to specific requirements. These systems are therefore recommended for regular use. The suitability of the two mayfly species for routine toxicity testing was evaluated. A. auriculata EC50 values showed a significant negative correlation with the corresponding average body-size (range 1476 - 1610 μm, mean 1555 μm). The different average body-sizes probably reflected the abundance of a certain size range present in the Palmiet River at the time of collection. Both species reacted similarly to Na₂S0₄ (similar slopes of the toxicity curves), identifying this salt as a slow acting toxicant. A. sudafricanum populations were more sensitive to Na₂S0₄ (EC50 3.404 g/L) than A. auriculata (EC50 8.090 g/L), probably because of its smaller body-size (mean 709 μm) and a lack of extremely tolerant individuals. In comparison to other freshwater macro invertebrates, including the standard toxicity test organism Daphnia spp., both mayfly species seemed to be moderately tolerant of Na₂S0₄; therefore there was no particular advantage to using these indigenous taxa rather than Daphnia spp. An assessment of the effects of elevated salinity/TDS levels on the test taxa yielded preliminary insights. A NaCI-EC50 for A. sudafricanum could be extrapolated and suggested a higher sensitivity to Na₂S0₄ than to NaCl. When Na₂S0₄ EC50 values of both species were compared to selected TDS levels of South African rivers, 4. auriculata would mostly not be affected, but A. sudafricanum might occasionally suffer from sub-lethal effects, depending on the sulphate proportion of the TDS. The South African guideline for TDS seemed to protect both species sufficiently.
- Full Text:
- Date Issued: 2000
Principals' perceptions of the management of staff appraisal in schools.
- Authors: Blaauw, Lindiwe Ellen
- Date: 2000
- Subjects: Educational evaluation , Teachers -- Rating of
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2011 , http://hdl.handle.net/10962/d1016080
- Description: Teacher appraisal has long been a contentious and contested area in educational management. The recent implementation of a new system of appraisal in Eastern Cape Schools has led to renewed interest in the role and management of appraisal. The objective of this study was to investigate principals' perception of the management of staff appraisal. An interpretive paradigm was adopted and the research is a case study of four secondary schools in Port Elizabeth. Two methods were used in collecting data, namely, questionnaires and interviews. The content comparative method was used to analyse the data. The findings of this study showed areas of continuities and discontinuities with the literature and the new document on appraisal. There is a clear understanding among the principals interviewed that staff appraisal should be used to assess individual teacher performance and that it should also be developmental. There is clear support from the principals on the involvement of other stakeholders. They see the process as transformative and participatory. They find it acceptable and are willing to be involved. However, the findings also indicate a lack of readiness on the part of the principals to fully embrace a fully participative and developmental approach to appraisal. On the strength of these findings I conclude the thesis by making recommendations for policy, principals, teachers and for future researchers in the field.
- Full Text:
- Date Issued: 2000
- Authors: Blaauw, Lindiwe Ellen
- Date: 2000
- Subjects: Educational evaluation , Teachers -- Rating of
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2011 , http://hdl.handle.net/10962/d1016080
- Description: Teacher appraisal has long been a contentious and contested area in educational management. The recent implementation of a new system of appraisal in Eastern Cape Schools has led to renewed interest in the role and management of appraisal. The objective of this study was to investigate principals' perception of the management of staff appraisal. An interpretive paradigm was adopted and the research is a case study of four secondary schools in Port Elizabeth. Two methods were used in collecting data, namely, questionnaires and interviews. The content comparative method was used to analyse the data. The findings of this study showed areas of continuities and discontinuities with the literature and the new document on appraisal. There is a clear understanding among the principals interviewed that staff appraisal should be used to assess individual teacher performance and that it should also be developmental. There is clear support from the principals on the involvement of other stakeholders. They see the process as transformative and participatory. They find it acceptable and are willing to be involved. However, the findings also indicate a lack of readiness on the part of the principals to fully embrace a fully participative and developmental approach to appraisal. On the strength of these findings I conclude the thesis by making recommendations for policy, principals, teachers and for future researchers in the field.
- Full Text:
- Date Issued: 2000
The interpretation of ABET placement tests in the recognition of prior learning
- Authors: Blunt, Sandra Viki
- Date: 2000
- Subjects: English language -- Ability testing , English language -- Study and teaching -- Foreign speakers
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1582 , http://hdl.handle.net/10962/d1003464
- Description: This thesis analyses the way in which placement testing is being interpreted in Adult Basic Education and Training (ABET). The thesis examines whether the placement tests used in the case study were valid in terms of whether their contents were relevant and authentic with regard to what English second language speakers could reasonably be expected to know. Adult learners have differing English second language knowledge depending on the different contexts in which they have learned their second language. This thesis investigates the implications of the different contexts and different language needs of adult learners for the testing of English as a second language for placement purposes in ABET programmes. The thesis examined two placement tests to determine how the recognition of prior second language learning was being interpreted and how the interpretation affected the validity of the tests. Learners= perceptions of the assessment process and test content were elicited in order to determine whether a policy of transparency had been followed in the implementation of the assessment. It was also established what the goals of the organisation were in implementing an ABET programme. This research suggests that placement testing should be viewed holistically; in other words, the goals of the organisation and the level of transparency affect the validity of the placement test. The conclusions were that the placement tests were inauthentic since their contents excluded certain vital aspects of real life performance, namely, that related to the work context. The research revealed that if the placement testing process and the ABET programme are integrated into the culture of the organisation and if employees are remunerated when they have passed the different levels in the programme, the programme is likely to achieve a fair measure of success. Recommendations are that literacy should be viewed as based on a variety of contexts and uses and that therefore tests should be tailored to suit each particular organisation and should contain workrelated content. Furthermore, multiple methods of assessment should be considered.
- Full Text:
- Date Issued: 2000
- Authors: Blunt, Sandra Viki
- Date: 2000
- Subjects: English language -- Ability testing , English language -- Study and teaching -- Foreign speakers
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:1582 , http://hdl.handle.net/10962/d1003464
- Description: This thesis analyses the way in which placement testing is being interpreted in Adult Basic Education and Training (ABET). The thesis examines whether the placement tests used in the case study were valid in terms of whether their contents were relevant and authentic with regard to what English second language speakers could reasonably be expected to know. Adult learners have differing English second language knowledge depending on the different contexts in which they have learned their second language. This thesis investigates the implications of the different contexts and different language needs of adult learners for the testing of English as a second language for placement purposes in ABET programmes. The thesis examined two placement tests to determine how the recognition of prior second language learning was being interpreted and how the interpretation affected the validity of the tests. Learners= perceptions of the assessment process and test content were elicited in order to determine whether a policy of transparency had been followed in the implementation of the assessment. It was also established what the goals of the organisation were in implementing an ABET programme. This research suggests that placement testing should be viewed holistically; in other words, the goals of the organisation and the level of transparency affect the validity of the placement test. The conclusions were that the placement tests were inauthentic since their contents excluded certain vital aspects of real life performance, namely, that related to the work context. The research revealed that if the placement testing process and the ABET programme are integrated into the culture of the organisation and if employees are remunerated when they have passed the different levels in the programme, the programme is likely to achieve a fair measure of success. Recommendations are that literacy should be viewed as based on a variety of contexts and uses and that therefore tests should be tailored to suit each particular organisation and should contain workrelated content. Furthermore, multiple methods of assessment should be considered.
- Full Text:
- Date Issued: 2000
Cumulative mild head injury in contact sport: a comparison of the cognitive profiles of rugby players and non-contact sport controls with normative data
- Authors: Bold, Lisa Clare
- Date: 2000
- Subjects: Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2935 , http://hdl.handle.net/10962/d1002444 , Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Description: This study investigates the effects of cumulative mild head injury on the cognitive functioning of elite rugby players. A comprehensive battery of neuropsychological tests was administered to top national (Springbok) rugby players (n=26), national Under 21 rugby players (n= 19), and a non-contact sport control group of national hockey players (n=21). The test results of the Total Rugby group (Springbok Rugby and Under 21 Rugby players), the Under 21 Rugby group, the hockey controls, and the Total Rugby and Under 21 Rugby forward and backline players respectively, were each compared with established normative data. Results showed significant differences in the direction of a poorer performance relative to the norms for the Total Rugby and Under 21 Rugby groups, and for the Total Rugby Forwards and Under 21 Rugby Forwards, on tests sensitive to the effects of diffuse brain damage. On the other hand, the Hockey Control group and the Total Rugby Backs and Under 21 Rugby Backs tended to perform within the normal range or better than the norm on some tests. These results confirm the hypothesis that rugby players, and the forward players in particular, are at risk of adverse cognitive effects consequent on cumulative mild head injury. The theoretical implications are that the aggregate effects of multiple exposures to mild head injuries in the rugby players served to reduce their brain reserve capacities and acted as a threshold-lowering influence associated with symptom onset.
- Full Text:
- Date Issued: 2000
- Authors: Bold, Lisa Clare
- Date: 2000
- Subjects: Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2935 , http://hdl.handle.net/10962/d1002444 , Head -- Wounds and injuries -- Psychology , Neuropsychological tests , Head -- Wounds and injuries , Sports injuries -- Psychological aspects
- Description: This study investigates the effects of cumulative mild head injury on the cognitive functioning of elite rugby players. A comprehensive battery of neuropsychological tests was administered to top national (Springbok) rugby players (n=26), national Under 21 rugby players (n= 19), and a non-contact sport control group of national hockey players (n=21). The test results of the Total Rugby group (Springbok Rugby and Under 21 Rugby players), the Under 21 Rugby group, the hockey controls, and the Total Rugby and Under 21 Rugby forward and backline players respectively, were each compared with established normative data. Results showed significant differences in the direction of a poorer performance relative to the norms for the Total Rugby and Under 21 Rugby groups, and for the Total Rugby Forwards and Under 21 Rugby Forwards, on tests sensitive to the effects of diffuse brain damage. On the other hand, the Hockey Control group and the Total Rugby Backs and Under 21 Rugby Backs tended to perform within the normal range or better than the norm on some tests. These results confirm the hypothesis that rugby players, and the forward players in particular, are at risk of adverse cognitive effects consequent on cumulative mild head injury. The theoretical implications are that the aggregate effects of multiple exposures to mild head injuries in the rugby players served to reduce their brain reserve capacities and acted as a threshold-lowering influence associated with symptom onset.
- Full Text:
- Date Issued: 2000
The implications of the introduction of outcomes based education in the natural sciences curriculum at Cape College of Education: the assessment of perceptions of squatter camp teachers in Khayelitsha towards the outcomes based education
- Authors: Booi, Kwanele
- Date: 2000
- Subjects: Competency-based education -- South Africa Competency-based education -- Evaluation Competency-based education -- South Africa -- Khayelitsha -- Evaluation Physical sciences -- Study and teaching -- Evaluation Life sciences -- Study and teaching -- Evaluation Cape College of Education
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1569 , http://hdl.handle.net/10962/d1003451
- Description: 1. This pilot study is a survey of practices of natural sciences educators at Cape College of Education to establish if they reflect the conceptual development, development of skills, change of attitudes and values that are the pillars of the Outcomes Based Education (OBE). Their approaches of lecturing have been assessed to determine if they incorporate investigative approaches based on social constructivism, the theory underpinning Curriculum 2005. The status of science education in the college has been analyzed to establish whether the curriculum can adapt itself to the specifications of the new curriculum. It has been concluded that the educators at Cape College of Education need to be empowered about strategies that will help them function along the principles embracing Curriculum 2005 specifications. The educators have shown not to be ready to practice social constructivism and the assessment strategies incorporated in their programmes do not embrace a variety of approaches that will enable their learners to develop conceptually, skill wise and enable them to develop change in attitudes and values. Investigative approaches to practical work appear to be lacking in the college teaching/learning and this also indicates that Curriculum 2005 will take time to be properly implemented at Cape College of Education. 2. This study is based on the practices of science educators in the squatter-camp school in Khayelitsha, a densely populated area for blacks near Cape Town. Teachers at Vuselela primary school were interviewed about their teaching assessment strategies to establish whether they incorporate a learner centred approach, which is the necessity for the Outcomes Based Education approach. Also some of the lessons they taught were observed in order to find out whether they validate what transpired from the interviews through a process of triangulation. It has become evident that the teachers are to some extent aware of the changes the education system is going through in South Africa. It also became clear from the study that the teachers are still lacking expertise as to how to practice along the lines of Curriculum 2005, the South African version of Outcomes Based Education (OBE). They also showed that they are keen to learn and practice OBE even though more opportunities need to be created for their epistemological empowerment as well as empowerment on the content of science.
- Full Text:
- Date Issued: 2000
- Authors: Booi, Kwanele
- Date: 2000
- Subjects: Competency-based education -- South Africa Competency-based education -- Evaluation Competency-based education -- South Africa -- Khayelitsha -- Evaluation Physical sciences -- Study and teaching -- Evaluation Life sciences -- Study and teaching -- Evaluation Cape College of Education
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1569 , http://hdl.handle.net/10962/d1003451
- Description: 1. This pilot study is a survey of practices of natural sciences educators at Cape College of Education to establish if they reflect the conceptual development, development of skills, change of attitudes and values that are the pillars of the Outcomes Based Education (OBE). Their approaches of lecturing have been assessed to determine if they incorporate investigative approaches based on social constructivism, the theory underpinning Curriculum 2005. The status of science education in the college has been analyzed to establish whether the curriculum can adapt itself to the specifications of the new curriculum. It has been concluded that the educators at Cape College of Education need to be empowered about strategies that will help them function along the principles embracing Curriculum 2005 specifications. The educators have shown not to be ready to practice social constructivism and the assessment strategies incorporated in their programmes do not embrace a variety of approaches that will enable their learners to develop conceptually, skill wise and enable them to develop change in attitudes and values. Investigative approaches to practical work appear to be lacking in the college teaching/learning and this also indicates that Curriculum 2005 will take time to be properly implemented at Cape College of Education. 2. This study is based on the practices of science educators in the squatter-camp school in Khayelitsha, a densely populated area for blacks near Cape Town. Teachers at Vuselela primary school were interviewed about their teaching assessment strategies to establish whether they incorporate a learner centred approach, which is the necessity for the Outcomes Based Education approach. Also some of the lessons they taught were observed in order to find out whether they validate what transpired from the interviews through a process of triangulation. It has become evident that the teachers are to some extent aware of the changes the education system is going through in South Africa. It also became clear from the study that the teachers are still lacking expertise as to how to practice along the lines of Curriculum 2005, the South African version of Outcomes Based Education (OBE). They also showed that they are keen to learn and practice OBE even though more opportunities need to be created for their epistemological empowerment as well as empowerment on the content of science.
- Full Text:
- Date Issued: 2000
Key decision-makers' perceptions of sustainable sea fisheries in Namibia and the implications for environmental education programmes
- Authors: Boois, Ulrich
- Date: 2000
- Subjects: Environmental education -- Namibia Fisheries -- Environmental aspects Fisheries -- Environmental aspects -- Namibia Sustainable development -- Environmental aspects Sustainable development -- Environmental aspects -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1661 , http://hdl.handle.net/10962/d1003544
- Description: This study investigates key decision-makers' perceptions of sustainable sea fisheries in Namibia, and explores the possibilities for the future development of education programmes that focus on "sustainability" in the fisheries sector. The concept of "sustainability" and its application in the context of a biological resource, namely sea fisheries, was examined. A series of questions were raised concerning sustainable fisheries: intergenerational implications of patterns of resource use, equity concerns, time horizons, and the protection of marine biodiveristy, among others. Examples from the Namibian and the European Community Sea Fisheries Industries are used to illustrate these issues. In spite of divergent views on what "sustainability" means, the study leads to certain findings that have broader policy implications. Data was collected from semi-structured interviews undertaken with six (6) key decision-makers in the Sea Fisheries Industry of Namibia, then analysed and assessed. The perceptions of key decisionmakers were determined by qualitative analysis in the interpretive paradigm. The data indicated some agreement in terms of what the key decision-makers think about the sustainable utilisation of the fisherjes resources. It is almost impossible to have complete agreement, because the decision-makers are from different contextual backgrounds. Those who make the decisions are more concerned about "how to manage" and those who act on the decisions put more emphasis on economic self-interest. Although the interviewees' perceptions of sustainable fisheries was imperfect, there was broad support for its aims and principles. The study also revealed that the achievement of sustainable sea fisheries development in Wamibia will require broader educational and public awareness programmes to enhance participation in decision-making debates. Formal and informal marine environmental education, from the perspective of "Responsible Fishing" has been emphasised.
- Full Text:
- Date Issued: 2000
- Authors: Boois, Ulrich
- Date: 2000
- Subjects: Environmental education -- Namibia Fisheries -- Environmental aspects Fisheries -- Environmental aspects -- Namibia Sustainable development -- Environmental aspects Sustainable development -- Environmental aspects -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1661 , http://hdl.handle.net/10962/d1003544
- Description: This study investigates key decision-makers' perceptions of sustainable sea fisheries in Namibia, and explores the possibilities for the future development of education programmes that focus on "sustainability" in the fisheries sector. The concept of "sustainability" and its application in the context of a biological resource, namely sea fisheries, was examined. A series of questions were raised concerning sustainable fisheries: intergenerational implications of patterns of resource use, equity concerns, time horizons, and the protection of marine biodiveristy, among others. Examples from the Namibian and the European Community Sea Fisheries Industries are used to illustrate these issues. In spite of divergent views on what "sustainability" means, the study leads to certain findings that have broader policy implications. Data was collected from semi-structured interviews undertaken with six (6) key decision-makers in the Sea Fisheries Industry of Namibia, then analysed and assessed. The perceptions of key decisionmakers were determined by qualitative analysis in the interpretive paradigm. The data indicated some agreement in terms of what the key decision-makers think about the sustainable utilisation of the fisherjes resources. It is almost impossible to have complete agreement, because the decision-makers are from different contextual backgrounds. Those who make the decisions are more concerned about "how to manage" and those who act on the decisions put more emphasis on economic self-interest. Although the interviewees' perceptions of sustainable fisheries was imperfect, there was broad support for its aims and principles. The study also revealed that the achievement of sustainable sea fisheries development in Wamibia will require broader educational and public awareness programmes to enhance participation in decision-making debates. Formal and informal marine environmental education, from the perspective of "Responsible Fishing" has been emphasised.
- Full Text:
- Date Issued: 2000
Environmental youth clubs in Namibia : what role do, could or should they play in environmental education?
- Authors: Botma, Connie
- Date: 2000
- Subjects: Environmental education -- Namibia Environmental education -- Study and teaching -- Namibia Youth -- Societies and clubs Youth -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1519 , http://hdl.handle.net/10962/d1003401
- Description: Although the existence of wildlife clubs in Africa dates back to the start of the environmental movement in the 1970s, youth involvement through environmental clubs only commenced in Namibia in 1992. I became involved with the clubs in 1995 when I was employed by the Rossing Foundation Environmental Education Project to encourage, support and coordinate environmental clubs in Namibia. During the last three years the number of Namibian clubs has increased from 20 to ±85, and they are now established in most geographical regions of the country. During my involvement with the clubs I became increasingly interested in the philosophical underpinnings of youth movements like clubs and started questioning what we could expect from the youth and what could be achieved through the clubs. One of my main concerns was whether youth could make a significant improvement to the quality of their lives and their environment through these clubs. The aim of my research was therefore to describe and reflect critically on the role of environmental youth clubs in environmental education in Namibia. My study was guided by a socially critical orientation which emphasises the construction of meaning through social dialogue and critical reflection. I chose an interpretative research strategy and generated data mainly through semi-structured interviews, participant observation, a focus-group discussion and a workshop. Due to the focus of the research I purposefully selected the sample of existing youth clubs to be included in the study. The iterative strategy of gathering and interpreting data in successive cycles allowed for continuous reflection throughout the research process. It also allowed me to identify key patterns and trends in analysing and interpreting the data. The study findings suggest that environmental clubs do playa role in learning about environmental issues; in developing personal and social identity, confidence and a sense of purpose in society; in establishing new and supportive relationships between teachers and learners and with other community resourde people; in creating opportunities and enabling exposure to diverse learning environments, options and alternatives; and ih fostering the orientation and skills needed to effect meaningful d1'inges in the environment. The findings also suggest that environmental clubs could make a significant contribution to environmental education, providing that they incorporate a socially critical orientation, gain greater recognition from significant adults and education officials, collaborate with other projects and organisations, and use guidelines of models such as the action research framework to ensure relevant and effective action projects. The main challenges to environmental clubs in Namibia include changing perceptions that youth do not have much to contribute; improving relationships between clubs, schools and communities; dealing with the tension between the possible disempowering effect of central control and the need for more formalised structures in order to gain official recognition; and developing strategies to ensure the clubs' sustainability in the future.
- Full Text:
- Date Issued: 2000
- Authors: Botma, Connie
- Date: 2000
- Subjects: Environmental education -- Namibia Environmental education -- Study and teaching -- Namibia Youth -- Societies and clubs Youth -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1519 , http://hdl.handle.net/10962/d1003401
- Description: Although the existence of wildlife clubs in Africa dates back to the start of the environmental movement in the 1970s, youth involvement through environmental clubs only commenced in Namibia in 1992. I became involved with the clubs in 1995 when I was employed by the Rossing Foundation Environmental Education Project to encourage, support and coordinate environmental clubs in Namibia. During the last three years the number of Namibian clubs has increased from 20 to ±85, and they are now established in most geographical regions of the country. During my involvement with the clubs I became increasingly interested in the philosophical underpinnings of youth movements like clubs and started questioning what we could expect from the youth and what could be achieved through the clubs. One of my main concerns was whether youth could make a significant improvement to the quality of their lives and their environment through these clubs. The aim of my research was therefore to describe and reflect critically on the role of environmental youth clubs in environmental education in Namibia. My study was guided by a socially critical orientation which emphasises the construction of meaning through social dialogue and critical reflection. I chose an interpretative research strategy and generated data mainly through semi-structured interviews, participant observation, a focus-group discussion and a workshop. Due to the focus of the research I purposefully selected the sample of existing youth clubs to be included in the study. The iterative strategy of gathering and interpreting data in successive cycles allowed for continuous reflection throughout the research process. It also allowed me to identify key patterns and trends in analysing and interpreting the data. The study findings suggest that environmental clubs do playa role in learning about environmental issues; in developing personal and social identity, confidence and a sense of purpose in society; in establishing new and supportive relationships between teachers and learners and with other community resourde people; in creating opportunities and enabling exposure to diverse learning environments, options and alternatives; and ih fostering the orientation and skills needed to effect meaningful d1'inges in the environment. The findings also suggest that environmental clubs could make a significant contribution to environmental education, providing that they incorporate a socially critical orientation, gain greater recognition from significant adults and education officials, collaborate with other projects and organisations, and use guidelines of models such as the action research framework to ensure relevant and effective action projects. The main challenges to environmental clubs in Namibia include changing perceptions that youth do not have much to contribute; improving relationships between clubs, schools and communities; dealing with the tension between the possible disempowering effect of central control and the need for more formalised structures in order to gain official recognition; and developing strategies to ensure the clubs' sustainability in the future.
- Full Text:
- Date Issued: 2000
Visual literacy in adult basic education : a study of ABET learners' visual perception with regard to their general level of English second language learning
- Authors: Bouwer, Anne Margaret
- Date: 2000
- Subjects: English language -- Study and teaching (Secondary) -- Foreign speakers Visual literacy -- South Africa Adult education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1821 , http://hdl.handle.net/10962/d1003707
- Description: Adult learners face many difficulties in their learning programmes, particularly due to the fact that having mastered literacy in their mother tongues, they move on to further educational programmes which are mostly produced in English. In contemporary society, people need to be adept in a number of literacies, termed multiliteracies. Adult learners are rarely taught visual competence as visual images are relegated to illustrations for written texts, and attention is mainly focussed on the all-important written word. Adult basic education learners need to be able to interpret pictures in books, newspapers and magazines, just as much as they need to be able to read and write. It is the premise of this research that visual literacy enhances thinking skills and that adult learners need to be actively taught how to interpret visual images in order to more ably deal with the written word, the more 'important' part of literacy. The goals of this research are to develop understanding of the processes which go into understanding images and text, and to examine how pictures can be used to help adult learners develop proficiency in English. Another goal is to teach learners the basics of visual literacy so as to improve their comprehension of the plethora of images surrounding them. The research findings could help to inform adult educators facing the current crisis in Adult Basic Education and Training in South Africa, focusing on a little-studied aspect of literacy, visual literacy, one of the critical outcomes in the new South African curriculum for Adult Education and one of the multiliteracies required by citizens of today's world.
- Full Text:
- Date Issued: 2000
- Authors: Bouwer, Anne Margaret
- Date: 2000
- Subjects: English language -- Study and teaching (Secondary) -- Foreign speakers Visual literacy -- South Africa Adult education -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1821 , http://hdl.handle.net/10962/d1003707
- Description: Adult learners face many difficulties in their learning programmes, particularly due to the fact that having mastered literacy in their mother tongues, they move on to further educational programmes which are mostly produced in English. In contemporary society, people need to be adept in a number of literacies, termed multiliteracies. Adult learners are rarely taught visual competence as visual images are relegated to illustrations for written texts, and attention is mainly focussed on the all-important written word. Adult basic education learners need to be able to interpret pictures in books, newspapers and magazines, just as much as they need to be able to read and write. It is the premise of this research that visual literacy enhances thinking skills and that adult learners need to be actively taught how to interpret visual images in order to more ably deal with the written word, the more 'important' part of literacy. The goals of this research are to develop understanding of the processes which go into understanding images and text, and to examine how pictures can be used to help adult learners develop proficiency in English. Another goal is to teach learners the basics of visual literacy so as to improve their comprehension of the plethora of images surrounding them. The research findings could help to inform adult educators facing the current crisis in Adult Basic Education and Training in South Africa, focusing on a little-studied aspect of literacy, visual literacy, one of the critical outcomes in the new South African curriculum for Adult Education and one of the multiliteracies required by citizens of today's world.
- Full Text:
- Date Issued: 2000
An investigation into dopamine-melatonin interactions in the rat Corpus striatum and pineal gland: a possible pineal-striatal axis
- Authors: Boyd, Clinton Shane
- Date: 2000
- Subjects: Pineal gland -- Research Melatonin Dopamine -- Physiological effect Dopamine Brain chemistry Rats -- Physiology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3906 , http://hdl.handle.net/10962/d1003965
- Description: Dysfunction of central dopaminergic systems has been implicated in neuroendocrine, neurodegenerative and psychiatric disorders. Monoamine oxidase and catechol-Omethyltransferase represent the key catabolic enzymes of dopamine, terminating neurotransmission following synaptic release of this catecholamine. Thus, both enzymes have been associated with the pathology of dopaminergic systems and represent therapeutic targets elf enormous clinical importance. Some neuroendocrine and circadian effects of melatonin have been attributed to an antidopamimetic effect of this pineal hormone in the hypothalamus and pituitary. Furthermore, both melatonin and dopamine modulate the behavioural output of the mesencephalic dopaminergic pathways of the basal ganglia, including movement disorders. However, the biochemical basis for the tonic inhibitory effect of melatonin in the nigro-striatal pathway has been poorly delineated. Thus, this study determined whether melatonin influences dopaminergic function in the corpus striatum of the Wistar rat by modulating monoamine oxidase and catecholO- methyltransferase activity. Reciprocally, the putative existence of an intrapineal dopaminergic system was investigated by determining the effect of selective dopaminergic agents, R-( -)apomorphine, haloperidol and dopamine, on indole metabolism of the pineal gland. The akinetic state of drug-induced catalepsy was employed as an animal model of Parkinson's disease to probe the neurotransmitter systems involved in the behavioural effects of melatonin. Indole metabolism was a reliable indicator of state-dependent metabolic fluxes in pineal gland function. These included a robust diurnal and seasonal variation in N-acetylserotonin and melatonin biosynthesis, and photoperiod- and drug-induced alterations of Inftabolism. The predominant changes could be attributed to an effect on serotonin N-acetyltransferase activity and/or the melatoninl5-methoxytryptophol ratio. Pineal 5-methoxyindole biosynthesis was determined primarily by the bioavailability of the corresponding 5-hydroxyindole and its affinity for hydroxyindole-O-methyltransferase. Evidence was found for the negative feedback or paracrine control of pineal indole metabolism by melatonin. A high inter-individual variability was observed in the biosynthesis of N-acetylserotonin and melatonin biosynthesis, and the weight of the pineal glands. Accordingly, the rats could be classified as either high or low capacity producers of these two indoles. R-(-)-apomorphine and dopamine in vitro, but not acute haloperidol in vivo, had dose- and phase-dependent effects on pineal indole metabolism. The predominant effect was a suppression of the scotophase-dependent induction ofN-acetylserotonin and melatonin biosynthesis by dopamine and R-( -)-apomorphine. It is postulated that these agonists inhibited nocturnal N-acetyltransferase activity via postsynaptic pineal D2 or D2-like receptors. The observed modulatory nature of the intrapineal dopaminergic system suggests that dopamine may be involved in the long-term regulation of pineal indole biosynthesis. Several lines of evidence are presented that the activity of striatal monoamine oxidase A and catechol-O-methyltransferase, represented predominantly by the soluble isoform, is statedependent and regulated in vivo by endogenous melatonin. Firstly, both enzymes showed a daynight variation in activity. Secondly, acute and subchronic administration and photoperiod manipulation studies indicated that both exogenous and endogenous melatonin inhibited each enzyme in a chronotypic fashion, with a more robust effect against catechol- -methyltransferase. The intensity of the in vivo effects was critically dependent on the dose, duration, route and the phase-timing of administration during the light dark cycle, and the length of the exposure to constant light. Melatonin in vitro had no effect on basal or Mg2+ -induced catechol-Omethyltransferase activity. Thus, it is proposed that the in vivo effects of the hormone can be attributed to a time-dependent change in the amount of active molecules of this enzyme. In contrast, melatonin and numerous other endogenous indolic compounds were found to be reversible inhibitors of striatal monoamine oxidase A in vitro. Structure-activity modeling revealed that the 5-methoxy moiety on the indole nucleus and substitution of the free primary amine of these compounds were the principal determinants of the potency and time-dependency of inhibition. Thus melatonin most likely has a direct inhibitory effect in vivo at the level of the active site of monoamine oxidase A. Exogenous melatonin alone had no cataleptogenic potential whereas a variety of behavioural responses were observed following intraperitoneal administration of y-hydroxybutyrate. The latter responses were state-dependent with day-night variations in intensity. Furthermore, yhydroxybutyrate stimulated melatonin biosynthesis during the photophase both in vitro and in vivo. These results point to a possible involvement of melatonin in the behavioural and neurochemical effects of y-hydroxybutyrate. Thus the general conclusion is that dopamine and melatonin display functional antagonism at the level of the pineal gland and corpus striatum of the Wistar rats. Therefore melatonin may be an important homeostatic modulator of dopaminergic neurotransmission throu~out the central nervous system. Furthermore, the putative existence of a functional pineal-striatal axis would greatly strengthen the argument for a holistic concept of brain homeostasis. The ability of endogenous melatonin to regulate monoamine oxidase A and catechol-O-methyltransferase may represent an alternative strategy for the treatment of disorders associated with these enzymes.
- Full Text:
- Date Issued: 2000
- Authors: Boyd, Clinton Shane
- Date: 2000
- Subjects: Pineal gland -- Research Melatonin Dopamine -- Physiological effect Dopamine Brain chemistry Rats -- Physiology
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3906 , http://hdl.handle.net/10962/d1003965
- Description: Dysfunction of central dopaminergic systems has been implicated in neuroendocrine, neurodegenerative and psychiatric disorders. Monoamine oxidase and catechol-Omethyltransferase represent the key catabolic enzymes of dopamine, terminating neurotransmission following synaptic release of this catecholamine. Thus, both enzymes have been associated with the pathology of dopaminergic systems and represent therapeutic targets elf enormous clinical importance. Some neuroendocrine and circadian effects of melatonin have been attributed to an antidopamimetic effect of this pineal hormone in the hypothalamus and pituitary. Furthermore, both melatonin and dopamine modulate the behavioural output of the mesencephalic dopaminergic pathways of the basal ganglia, including movement disorders. However, the biochemical basis for the tonic inhibitory effect of melatonin in the nigro-striatal pathway has been poorly delineated. Thus, this study determined whether melatonin influences dopaminergic function in the corpus striatum of the Wistar rat by modulating monoamine oxidase and catecholO- methyltransferase activity. Reciprocally, the putative existence of an intrapineal dopaminergic system was investigated by determining the effect of selective dopaminergic agents, R-( -)apomorphine, haloperidol and dopamine, on indole metabolism of the pineal gland. The akinetic state of drug-induced catalepsy was employed as an animal model of Parkinson's disease to probe the neurotransmitter systems involved in the behavioural effects of melatonin. Indole metabolism was a reliable indicator of state-dependent metabolic fluxes in pineal gland function. These included a robust diurnal and seasonal variation in N-acetylserotonin and melatonin biosynthesis, and photoperiod- and drug-induced alterations of Inftabolism. The predominant changes could be attributed to an effect on serotonin N-acetyltransferase activity and/or the melatoninl5-methoxytryptophol ratio. Pineal 5-methoxyindole biosynthesis was determined primarily by the bioavailability of the corresponding 5-hydroxyindole and its affinity for hydroxyindole-O-methyltransferase. Evidence was found for the negative feedback or paracrine control of pineal indole metabolism by melatonin. A high inter-individual variability was observed in the biosynthesis of N-acetylserotonin and melatonin biosynthesis, and the weight of the pineal glands. Accordingly, the rats could be classified as either high or low capacity producers of these two indoles. R-(-)-apomorphine and dopamine in vitro, but not acute haloperidol in vivo, had dose- and phase-dependent effects on pineal indole metabolism. The predominant effect was a suppression of the scotophase-dependent induction ofN-acetylserotonin and melatonin biosynthesis by dopamine and R-( -)-apomorphine. It is postulated that these agonists inhibited nocturnal N-acetyltransferase activity via postsynaptic pineal D2 or D2-like receptors. The observed modulatory nature of the intrapineal dopaminergic system suggests that dopamine may be involved in the long-term regulation of pineal indole biosynthesis. Several lines of evidence are presented that the activity of striatal monoamine oxidase A and catechol-O-methyltransferase, represented predominantly by the soluble isoform, is statedependent and regulated in vivo by endogenous melatonin. Firstly, both enzymes showed a daynight variation in activity. Secondly, acute and subchronic administration and photoperiod manipulation studies indicated that both exogenous and endogenous melatonin inhibited each enzyme in a chronotypic fashion, with a more robust effect against catechol- -methyltransferase. The intensity of the in vivo effects was critically dependent on the dose, duration, route and the phase-timing of administration during the light dark cycle, and the length of the exposure to constant light. Melatonin in vitro had no effect on basal or Mg2+ -induced catechol-Omethyltransferase activity. Thus, it is proposed that the in vivo effects of the hormone can be attributed to a time-dependent change in the amount of active molecules of this enzyme. In contrast, melatonin and numerous other endogenous indolic compounds were found to be reversible inhibitors of striatal monoamine oxidase A in vitro. Structure-activity modeling revealed that the 5-methoxy moiety on the indole nucleus and substitution of the free primary amine of these compounds were the principal determinants of the potency and time-dependency of inhibition. Thus melatonin most likely has a direct inhibitory effect in vivo at the level of the active site of monoamine oxidase A. Exogenous melatonin alone had no cataleptogenic potential whereas a variety of behavioural responses were observed following intraperitoneal administration of y-hydroxybutyrate. The latter responses were state-dependent with day-night variations in intensity. Furthermore, yhydroxybutyrate stimulated melatonin biosynthesis during the photophase both in vitro and in vivo. These results point to a possible involvement of melatonin in the behavioural and neurochemical effects of y-hydroxybutyrate. Thus the general conclusion is that dopamine and melatonin display functional antagonism at the level of the pineal gland and corpus striatum of the Wistar rats. Therefore melatonin may be an important homeostatic modulator of dopaminergic neurotransmission throu~out the central nervous system. Furthermore, the putative existence of a functional pineal-striatal axis would greatly strengthen the argument for a holistic concept of brain homeostasis. The ability of endogenous melatonin to regulate monoamine oxidase A and catechol-O-methyltransferase may represent an alternative strategy for the treatment of disorders associated with these enzymes.
- Full Text:
- Date Issued: 2000
Genetic variation within and between some rare and common taxa of Cape Proteaceae and the implications for their conservation
- Authors: Brown, Susan Ann
- Date: 2000
- Subjects: Proteaceae -- South Africa Nature conservation -- South Africa Plant conservation -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3905 , http://hdl.handle.net/10962/d1003964
- Full Text:
- Date Issued: 2000
- Authors: Brown, Susan Ann
- Date: 2000
- Subjects: Proteaceae -- South Africa Nature conservation -- South Africa Plant conservation -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3905 , http://hdl.handle.net/10962/d1003964
- Full Text:
- Date Issued: 2000
Distributed authentication for resource control
- Authors: Burdis, Keith Robert
- Date: 2000
- Subjects: Computers -- Access control , Data protection , Computer networks -- Security measures , Electronic data processing departments -- Security measures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4630 , http://hdl.handle.net/10962/d1006512 , Computers -- Access control , Data protection , Computer networks -- Security measures , Electronic data processing departments -- Security measures
- Description: This thesis examines distributed authentication in the process of controlling computing resources. We investigate user sign-on and two of the main authentication technologies that can be used to control a resource through authentication and providing additional security services. The problems with the existing sign-on scenario are that users have too much credential information to manage and are prompted for this information too often. Single Sign-On (SSO) is a viable solution to this problem if physical procedures are introduced to minimise the risks associated with its use. The Generic Security Services API (GSS-API) provides security services in a manner in- dependent of the environment in which these security services are used, encapsulating security functionality and insulating users from changes in security technology. The un- derlying security functionality is provided by GSS-API mechanisms. We developed the Secure Remote Password GSS-API Mechanism (SRPGM) to provide a mechanism that has low infrastructure requirements, is password-based and does not require the use of long-term asymmetric keys. We provide implementations of the Java GSS-API bindings and the LIPKEY and SRPGM GSS-API mechanisms. The Secure Authentication and Security Layer (SASL) provides security to connection- based Internet protocols. After finding deficiencies in existing SASL mechanisms we de- veloped the Secure Remote Password SASL mechanism (SRP-SASL) that provides strong password-based authentication and countermeasures against known attacks, while still be- ing simple and easy to implement. We provide implementations of the Java SASL binding and several SASL mechanisms, including SRP-SASL.
- Full Text:
- Date Issued: 2000
- Authors: Burdis, Keith Robert
- Date: 2000
- Subjects: Computers -- Access control , Data protection , Computer networks -- Security measures , Electronic data processing departments -- Security measures
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4630 , http://hdl.handle.net/10962/d1006512 , Computers -- Access control , Data protection , Computer networks -- Security measures , Electronic data processing departments -- Security measures
- Description: This thesis examines distributed authentication in the process of controlling computing resources. We investigate user sign-on and two of the main authentication technologies that can be used to control a resource through authentication and providing additional security services. The problems with the existing sign-on scenario are that users have too much credential information to manage and are prompted for this information too often. Single Sign-On (SSO) is a viable solution to this problem if physical procedures are introduced to minimise the risks associated with its use. The Generic Security Services API (GSS-API) provides security services in a manner in- dependent of the environment in which these security services are used, encapsulating security functionality and insulating users from changes in security technology. The un- derlying security functionality is provided by GSS-API mechanisms. We developed the Secure Remote Password GSS-API Mechanism (SRPGM) to provide a mechanism that has low infrastructure requirements, is password-based and does not require the use of long-term asymmetric keys. We provide implementations of the Java GSS-API bindings and the LIPKEY and SRPGM GSS-API mechanisms. The Secure Authentication and Security Layer (SASL) provides security to connection- based Internet protocols. After finding deficiencies in existing SASL mechanisms we de- veloped the Secure Remote Password SASL mechanism (SRP-SASL) that provides strong password-based authentication and countermeasures against known attacks, while still be- ing simple and easy to implement. We provide implementations of the Java SASL binding and several SASL mechanisms, including SRP-SASL.
- Full Text:
- Date Issued: 2000
An investigative case study of the introduction of democratic decision-making within an East London secondary school
- Authors: Carelse, Garth Craig
- Date: 2000
- Subjects: School management and organization -- South Africa Decision making -- Cast studies Education and state Ebenezer Majombozi High
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1920 , http://hdl.handle.net/10962/d1007404
- Description: The move towards greater democracy and participation in our education system is legislated quite succinctly in our South African Schools Act. The Act furthermore, and more importantly for this case study, posits that decision-making should be democratic in nature and our schools should eventually become governed in a collaborative and co-operative manner. Other policy texts such as the Labour Relations Act and the South African Constitution canonise the demand for a democratic South African society. This study investigates how democratic decision-making practices are taking place in an East London Secondary School namely Ebenezer Majombozi High. Even though distinct links exist between management and governance arms of schools, this study concentrates predominantly on decision-making within the school governing body and touches briefly on management thinking trends as a theoretical background to the kind of management at the school. What makes the school interesting as a case study is its rich history and its location in a deprived and impoverished township environment. The school was also part of the ex-Department of Education and Training, the black educational department of the past apartheid state. The kind of research undertaken was in the form of unstructured personal interviews with influential stakeholders at the school. Some of these stakeholders fonn part of the school governing body and the questions asked probed forms of governance at the school and how decision-making impacted on the overall school governance. The research findings acknowledges that decision-making does occur democratically at the school but that the practical implementation of positive consensual decisions are rarely realized. The school governing body only meets to deal with crises underpinned by a lack of learning and teaching and has not even debated the policies within the South African Schools Act. The study also argues that only by building capacity within the school and empowering the stakeholders, can constructive participation by all become a reality.
- Full Text:
- Date Issued: 2000
- Authors: Carelse, Garth Craig
- Date: 2000
- Subjects: School management and organization -- South Africa Decision making -- Cast studies Education and state Ebenezer Majombozi High
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1920 , http://hdl.handle.net/10962/d1007404
- Description: The move towards greater democracy and participation in our education system is legislated quite succinctly in our South African Schools Act. The Act furthermore, and more importantly for this case study, posits that decision-making should be democratic in nature and our schools should eventually become governed in a collaborative and co-operative manner. Other policy texts such as the Labour Relations Act and the South African Constitution canonise the demand for a democratic South African society. This study investigates how democratic decision-making practices are taking place in an East London Secondary School namely Ebenezer Majombozi High. Even though distinct links exist between management and governance arms of schools, this study concentrates predominantly on decision-making within the school governing body and touches briefly on management thinking trends as a theoretical background to the kind of management at the school. What makes the school interesting as a case study is its rich history and its location in a deprived and impoverished township environment. The school was also part of the ex-Department of Education and Training, the black educational department of the past apartheid state. The kind of research undertaken was in the form of unstructured personal interviews with influential stakeholders at the school. Some of these stakeholders fonn part of the school governing body and the questions asked probed forms of governance at the school and how decision-making impacted on the overall school governance. The research findings acknowledges that decision-making does occur democratically at the school but that the practical implementation of positive consensual decisions are rarely realized. The school governing body only meets to deal with crises underpinned by a lack of learning and teaching and has not even debated the policies within the South African Schools Act. The study also argues that only by building capacity within the school and empowering the stakeholders, can constructive participation by all become a reality.
- Full Text:
- Date Issued: 2000