An investigation into improved ionospheric F1 layer predictions over Grahamstown, South Africa
- Authors: Jacobs, Linda
- Date: 2005
- Subjects: Ionosphere , Ionospheric electron density -- South Africa -- Grahamstown , Neural networks (Computer Science)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5511 , http://hdl.handle.net/10962/d1008094 , Ionosphere , Ionospheric electron density -- South Africa -- Grahamstown , Neural networks (Computer Science)
- Description: This thesis describes an analysis of the F1 layer data obtained from the Grahamstown (33.32°S, 26.500 E), South Africa ionospheric station and the use of this data in improving a Neural Network (NN) based model of the F1 layer of the ionosphere. An application for real-time ray tracing through the South African ionosphere was identified, and for this application real-time evaluation of the electron density profile is essential. Raw real-time virtual height data are provided by a Lowell Digisonde (DPS), which employs the automatic scaling software, ARTIST whose output includes the virtual-toreal height data conversion. Experience has shown that there are times when the ray tracing performance is degraded because of difficulties surrounding the real-time characterization of the F1 region by ARTIST. Therefore available DPS data from the archives of the Grahamstown station were re-scaled manually in order to establish the extent of the problem and the times and conditions under which most inaccuracies occur. The re-scaled data were used to update the F1 contribution of an existing NN based ionospheric model, the LAM model, which predicts the values of the parameters required to produce an electron density profile. This thesis describes the development of three separate NNs required to predict the ionospheric characteristics and coefficients that are required to describe the F1 layer profile. Inputs to the NNs include day number, hour and measures of solar and magnetic activity. Outputs include the value of the critical frequency of the F1 layer, foF1, the real height of reflection at the peak, hmFl, as well as information on the state of the F1 layer. All data from the Grahamstown station from 1973 to 2003 was used to train these NNs. Tests show that the predictive ability of the LAM model has been improved by incorporating the re-scaled data.
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- Date Issued: 2005
An investigation into perceptions of learner participation in the governance of secondary schools
- Authors: Nongubo, Mphuthumi J
- Date: 2005
- Subjects: Education and state -- South Africa , School management and organization -- South Africa , Education, Secondary -- South Africa , Student government -- South Africa , Student participation in administration -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:2007 , http://hdl.handle.net/10962/d1015747
- Description: The question of learner participation or involvement in school governance has been a thorny issue in South Africa for decades. This study investigated secondary learners’ participation in the governance of their schools through representation by the Representative Council of Learners (RCLs), formerly known as school representative councils (SRCs). The study attempted to find out how learners participation is perceived by both the RCLs and the School Management Teams (SMTs). The study was conducted in five secondary schools in the Eastern Cape townships of Grahamstown. The research participants were members of School Management Teams and Representative Councils of Learners from these schools. The study was oriented in an interpretive paradigm following a qualitative approach. Questionnaires and in-depth semi-structured interviews were used to explore the perceptions of the two groups involved. The Department of Education documents that sanction RCL participation were referred to throughout and especially when analysing the respondents’ views. The main finding of the study is that learner involvement in school governance is still problematic, though it is presently provided for by policies that govern schools, including the South African Schools Act and the Guides for Representative Councils of Learners of 1999, in which their roles are outlined. The findings of the study reveal an indecisive and autocratic mindset among educators regarding the issue of learner involvement in governance and management. Furthermore, the Department of Education documents in place betray a narrow conception of RCL participation in school governance and still display an element of mistrust towards the learners concerning their roles in governance. As a result of these forces, the democratic potential of learner participation is undermined, and RCLs compromised as legitimate stakeholders.
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- Date Issued: 2005
An investigation into the antidepressant activity of hypericum perforatum
- Authors: Stephens, Linda Lee
- Date: 2005
- Subjects: Hypericum perforatum -- Physiological effect Hypericum perforatum -- Therapeutic use Antidepressants
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3793 , http://hdl.handle.net/10962/d1003271
- Description: Hypericum perforatum is a herbal medicine that has been used for centuries for the treatment of depression. Many studies have been conducted in the Northern hemisphere on the efficacy of the HP extracts produced there. These studies include clinical trials and pharmacological investigations using a standardised HP extract or a fraction of the HP extract containing certain compounds, such as hypericin, pseudohypericin, hyperforin and several of the flavonoids thought to be responsible for the antidepressant activity. The mechanism of action of HP and its constituents is still not completely clear and it is speculated that the antidepressant activity is the result of several of the compounds acting synergistically. HP is indigenous to and also cultivated in the Western Cape of South Africa. Extracts from these plants are sold in the local health shops and there are no previous studies evaluating the efficacy of these products. The aim of this thesis is to investigate the antidepressant activity of one of these products and two of its constituents, quercetin and caffeic acid, to gain further insight into their mode of antidepressant action and to compare these results with similar studies which used a standardised extract produced in the northern hemisphere. The first study investigated the effect of HP, quercetin and caffeic acid on pineal metabolism. Changes in the synthesis of melatonin produced by the pineal gland have been implicated in depression. The results showed an increase in the level of melatonin produced in the animals treated with quercetin, which suggests that this compound may mediate antidepressant activity through such a mechanism. There are no previous reports on the in vivo effects of HP or any of its constituents on pineal metabolism. The second study investigated the effect of HP, quercetin and caffeic acid on the activity of the liver enzyme, tryptophan-2,3-dioxygenase (TDO). Inhibition of this enzyme has been shown to increase plasma levels of tryptophan, a precursor of serotonin and thereby result in increased serotonin levels in the brain. Low levels of serotonin in the brain have been implicated in depression. This study revealed significant inhibition of TDO by caffeic acid and this suggests that this constituent of HP could be contributing to its antidepressant activity through such a mechanism. There are no previous reports investigating the in vivo effect of HP or any of its constituents on TDO activity. Modulation of the levels of indoleamines, serotonin (5-HT) and dopamine (DA) as well as the metabolites, 3,4 dihydroxyphenyl acetic acid (DOPAC), 5-hydroxyindole acetic acid (5-HIAA) and homovallinic acid (HVA) in the brain have been implicated in the neuropharmacology of depression. Different studies using enzyme-linked immunosorbant assay (ELISA), high performance liquid chromatography with electrochemical detection (HPLC-ECD) and liquid chromatography-mass spectrometry (LC-MS) were used to determine changes in the levels of these indoleamines brought about after treatment with HP caffeic acid and quercetin. The results of the ELISA study showed significant increases in 5-HT levels in the brains of the animals treated with caffeic acid and quercetin. The results of the HPLC-ECD studies also revealed significant increases in 5-HT levels and a decrease in the turnover of 5-HT in the animals treated with quercetin. A significant increase in DA levels in the animals treated with quercetin was shown in both the HPLC-ECD and LC-MS studies. There was also an increase in DA turnover in the animals treated with HP shown in the HPLC-ECD and LC-MS studies. These results suggest that HP and its constituents, quercetin and caffeic acid mediate their antidepressant effects through serotonergic and dopaminergic neurotransmission. Adaptive changes in the density of b-adrenergic (b-AR), 5-HT2 and N-methyl-D-aspartate (NMDA) receptors have been implicated in depression. Several studies, investigating the effect of treatment with HP and quercetin on these different receptor densities, were undertaken using radioactive binding assays. Treatment with HP resulted in significant down regulation of b-AR and NMDA receptor densities and up-regulation of 5HT2 receptors. The effects on the b-AR and 5-HT2 receptors are similar to the results reported using HP in the Northern hemisphere, but the effect on the NMDA receptors is novel providing insight into the mode of action of HP. Apoptosis of neuronal cells has been implicated in neuro-degenerative and depressive disorders. Detection of apoptosis, using fluorescent microscopy observed through the labelling of DNA strand breaks, showed a decrease in the amount of apoptosis in the animals treated with HP and quercetin. This adds further support for the use of HP as an antidepressant and these results are similar to results reported from the Northern hemisphere. The results of all these studies suggest that the quality of the locally produced tincture is similar in efficacy to that of the standardised product of the Northern hemisphere.
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- Date Issued: 2005
An investigation into the neuroprotective properties of acetylsalicylic acid and acetaminophen
- Authors: Maharaj, Himant
- Date: 2005
- Subjects: Aspirin Acetaminophen Analgesics Alzheimer's disease -- Treatment Parkinson's disease
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3769 , http://hdl.handle.net/10962/d1003247
- Description: The potent analgesic property of acetylsalicylic acid and acetaminophen makes these the most commonly used analgesics in the world. Easy accessibility and cost effectiveness of these agents are attractive to patients seeking pain relief. However, the abuse of nonnarcotic analgesics such as acetaminophen and acetylsalicylic acid by alcoholics and patients seeking to relieve dysphoric moods is well documented. These agents therefore impact on the brain neurotransmitter levels and therefore all processes involved in the synthesis and metabolism of neurotransmitters may be affected. The use of non-narcotic analgesics has been reported to reduce the incidence of neurodegenerative disorders such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). The mode of action by which acetylsalicylic acid and acetaminophen elicit neuroprotection is however unclear as many mechanisms of action have been inconclusively postulated. The first part of this study aims to elucidate the various mechanisms by which acetylsalicylic acid and acetaminophen affect the enzymes responsible for the catabolism of tryptophan, which is a precursor for the mood elevating neurotransmitter serotonin, as well as to investigate whether these agents alter the interplay between serotonin and pineal indole metabolism. The second part of this study focuses on the neuroprotective properties of acetylsalicylic acid and acetaminophen utilizing the neurotoxic metabolite of the kynurenine pathway, quinolinic acid and the potent Parkinsonian neurotoxin, 1-methyl-4-phenylpyridinium (MPP+). The ability of acetylsalicylic acid and acetaminophen to alter TRP metabolism was determined by investigating the effects of these agents on the primary enzymes of the kynurenine pathway i.e. tryptophan 2, 3-dioxygenase and indoleamine 2,3-dioxygenase as well as to investigate whether these agents would have any effects on 3-hydroxyanthranilic acid oxygenase. 3-Hydroxyanthranilic acid oxygenase is the enzyme responsible for the synthesis of quinolinic acid. Acetylsalicylic acid and acetaminophen alter tryptophan metabolism by inhibiting tryptophan 2, 3-dioxygenase and indoleamine 2,3-dioxygenase thus increasing the availability of tryptophan for the production of serotonin. Acetylsalicylic acid and acetaminophen also inhibit 3-hydroxyanthranilic acid oxygenase thus implying that these agents could reduce quinolinic acid production. Acetaminophen administration in rats induces a rise in serotonin and norepinephrine in the forebrain. Acetylsalicylic acid curtails the acetaminophen-induced rise in brain norepinephrine levels as well as enhances serotonin metabolism, indicating that analgesic preparations containing both agents would be advantageous, as this would prevent acetaminophen-induced mood elevation. The results from the pineal indole metabolism study show that acetylsalicylic acid enhances pineal metabolism of serotonin whereas acetaminophen induces an increase in melatonin levels in the pineal gland. Neuronal damage due to oxidative stress has been implicated in several neurodegenerative disorders such as AD and PD. The second part of the study aims to elucidate and characterize the mechanism by which acetylsalicylic acid and acetaminophen afford neuroprotection. The hippocampus is an important region of the brain responsible for memory. Agents such as quinolinic acid that are known to induce stress in this area have detrimental effects and could lead to various types of dementia. The striatum is also a vulnerable region to oxidative stress and hence (MPP+), which is toxic for this particular region of the brain, was also used as a neurotoxin. The results show that ASA and acetaminophen alone and in combination, are potent superoxide anion scavengers. In addition, the results imply that these agents offer protection against oxidative stress and lipid peroxidation induced by several neurotoxins in rat brain particularly, the hippocampus and striatum. Histological studies, using Nissl staining and Acid fuchsin, show that acetylsalicylic acid and acetaminophen are able to protect hippocampal neurons against quinolinic acidinduced necrotic cell death. Immunohistochemical investigations show that QA induces apoptotic cell death in the hippocampus, which is inhibited by ASA and acetaminophen. In addition, ASA and acetaminophen inhibited MPP+ induced apoptotic cell death in the rat striatum. The study also sought to elucidate possible mechanisms by which ASA and acetaminophen exert neuroprotective effects in the presence of MPP+ as these agents are shown to prevent the MPP+-induced reduction in dopamine levels. The results show that acetylsalicylic acid and acetaminophen inhibit the action of this neurotoxin on the mitochondrial electron transport chain, a common source of free radicals in the cell. In addition, these agents were shown to block the neurotoxic effects of MPP+ on the enzymatic defence system of the brain i.e. superoxide dismutase, glutathione peroxidase and catalase. The reduction in glutathione levels induced by MPP+ is significantly inhibited by acetylsalicylic acid and acetaminophen. The results imply that these agents are capable of not only scavenging free radicals but also enhance the cell defence mechanism against toxicity in the presence of MPP+. These agents also block the MPP+-induced inhibition of dopamine uptake into the cell. This would therefore reduce auto-oxidation of dopamine thus implying another mechanism by which these agents exert a neuroprotective role in MPP+-induced neurotoxicity. The discovery of neuroprotective properties of acetylsalicylic acid and acetaminophen is important considering the high usage of these agents and the increased incidence in neurological disorders. The findings of this thesis point to the need for clinical studies to be conducted as the results show acetylsalicylic acid and acetaminophen to have a definite role to play as antioxidants. This study therefore provides novel information regarding the neuroprotective effects of these agents and favours the use of these agents in the treatment of neurodegenerative disorders, such as AD and PD, in which oxidative stress is implicated.
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- Date Issued: 2005
An investigation into the pharmacological properties of propolis
- Authors: Hu, Fuliang
- Date: 2005
- Subjects: Propolis
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5831 , http://hdl.handle.net/10962/d1007955
- Description: Propolis is a traditional value-added product from beekeeping, and has been widely used in medicine and the chemical industry because of its extensive biological activities. In this dissertation some pharmacological properties of propolis extracted by ethanol (EEP) and water (WSP) were studied by means of modem pharmacological methods. The results of the experiments show the following: 1. Both EEP and WSD led to decreased levels of fasting blood glucose (FBG), glycosylated haemoglobin (HBA1c), Fructosamine (FRU), blood urea nitrogen (BUN), uric acid (UA), malonaldehyde (MDA), nitric oxide (NO), nitric oxide synthetase (NOS), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C) and very-low density lipoprotein cholesterol (VLDL-C) in the serum of fasting rats; and, to increased serum levels of high-density lipoprotein cholesterol (HDL-C) and superoxide dismutase (SOD) in rats with diabetes mellitus. This suggests that propolis can control blood glucose and modulate the metabolism of glucose, blood lipid and protein, leading to decreased outputs of lipid peroxidation and scavenging free radicals in rats with diabetes mellitus. 2. Both EEP and WSD showed inhibitory effects on swelling induced by Freund's complete adjuvant and decreased the degree of local inflammatory responses; significantly inhibited the increase of interleukin-6 (lL-6) in inflamed tissues, but had no significant effect on levels of interleukin-2 (IL-2) and interferon-y (IFN-y). The results are consistent with the interpretation that EEP and WSD may exert these effects by inhibiting the activation and differentiation of mononuclear macrophages. 3. Both EEP and WSD exhibited significant anti-inflammatory effects in animal models with respect to thoracic capillary vessel leakage in mice, Carrageenan-induced oedema, Carrageen-aninduced pleurisy and acute lung damage in rats. The mechanisms for the anti-inflammatory effects probably involve decreasing prostaglandin and NO levels. 4. Both EEP and WSD had an inhibitory effect on the level of TG, TC, LDL-C, glutamic-pyruvic transaminase (GPT) and glutamic-oxalacetic transaminase (GOT) in serum, and TC, TG and MDA in liver of hyperlipidemic SD rats; but were without effects on HDL-C, MDA, SOD and NO in serum. EEP also reduced body weight, liver weight and liver index, but WSD did not reduce those indexes. The results showed that the two extracts contribute to the improvement of lipid metabolism in hyperlipidemic rats and provide them with the required anti-oxidative activity. 5. The 80% ethanol extracts of propolis had the highest flavonoid content. The flavone content of water extracts of propolis were obtained with a natural surface-active agent, under ultrasonic perturbation at 80°C, for 12 h and was 6.7 times greater than that of propolis extracted with water at room temperature. Compared to EEP, WSD has the same or a greater anti-tumor or anti-inflammation effect at the same dosage, and shows considerable pharmacological potential especially because of its low side effects and ease of preparation.
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- Date Issued: 2005
An investigation into the possible neuroprotective or neurotoxic properties of metrifonate
- Authors: Ramsunder, Adrusha
- Date: 2005 , 2013-06-11
- Subjects: Nervous system -- Degeneration -- Treatment , Neurotoxic agents , Alzheimer's disease -- Treatment , Metrifonate
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3833 , http://hdl.handle.net/10962/d1007560 , Nervous system -- Degeneration -- Treatment , Neurotoxic agents , Alzheimer's disease -- Treatment , Metrifonate
- Description: Alzheimer's disease is a progressive neurodegenerative disorder, in which there is a marked decline in neurotransmitters, especially those of the cholinergic pathways. One of the approaches to the symptomatic treatment of Alzheimer's disease is the inhibition of the breakdown of the neurotransmitter acetylcholine, using an acetylcholinesterase inhibitor. One such drug tested, is the organophosphate, metrifonate. Any drug used for the treatment of neurodegenerative disorders should preferably not induce further neurological damage. Thus, in the present study, we investigated whether or not metrifonate is neuroprotective. The in vivo and in vitro effect of this drug on free radicals generation shows that metrifonate increases the level ofthese reactive species. Lipid peroxidation induced using quinolinic acid (QA) and iron (II) and show that metrifonate increased the peroxidative damage induced by using quinolinic acid. Metrifonate is also able to induce lipid peroxidation both in vivo and in vitro. This was reduced in vitro in the presence of melatonin. Using iron (II), in vi/ro, there was no significant difference in the level of lipid peroxidation in the presence of this drug. An investigation of the activity of the mitochondrial electron transport chain and complex I of the electron transport chain in the presence of metrifonate revealed that metrifonate reduces the activity of the electron transport chain at the level of complex I. The activity of the mitochondrial electron transport chain was restored in the presence of melatonin. Pineal organ culture showed that metrifonate does not increase melatonin production. Histological and apoptosis studies show that tissue necrosis and apoptosis respectively, occur in the presence of this agent, which is reduced in the presence of melatonin. Metal binding studies were performed USing ultraviolet spectroscopy, and electrochemical analysis to examine the interaction of metrifonate with iron (II) and iron (III). No shift in the peak was observed in the ultraviolet spectrum when iron (ll) was added to metrifonate. Electrochemical studies show that there may be a very weak or no ligand formed between the metal and drug. This study shows that while drugs such as metrifonate may be beneficial in restoring cognitive function in Alzheimer's disease, it could also have the potential to enhance neurodegeneration, thus worsening the condition, in the long term. , KMBT_363 , Adobe Acrobat 9.54 Paper Capture Plug-in
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- Date Issued: 2005
An investigation of an undergraduate course module on the ethical aspects of information systems
- Authors: Charlesworth, Matthew
- Date: 2005
- Subjects: Information technology , Information technology -- Moral and ethical aspects , Computers -- Moral and ethical aspects , Computer science -- Study and teaching (Higher) -- Curricula , Computer engineering -- Study and teaching (Higher) -- Curricula , Software engineering -- Study and teaching (Higher) -- Curricula , Information technology -- study and teaching (Higher) -- Curricula
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1139 , http://hdl.handle.net/10962/d1002768 , Information technology , Information technology -- Moral and ethical aspects , Computers -- Moral and ethical aspects , Computer science -- Study and teaching (Higher) -- Curricula , Computer engineering -- Study and teaching (Higher) -- Curricula , Software engineering -- Study and teaching (Higher) -- Curricula , Information technology -- study and teaching (Higher) -- Curricula
- Description: An increased emphasis is being placed on ethics in Information Systems. An investigation of: the relevant literature which highlighted the growth of, and importance in understanding the moral philosophies which underlie Computer Ethics; and the official curricula recommendations that have increasingly and consistently recommended inclusion of courses describing the Social, Professional and Ethical responsibilities of Information Systems Professionals; and informed by the observations from two empirical Studies that showed the extent of unethical behaviour, and how this behaviour is diminished in those who have received formal tertiary level education resulted in a proposed new course module on Ethics in Information Systems. The module follows a sandwich-approach whereby two stand-alone modules are conducted on either side of integrated Computer Ethics content within the rest of the curriculum.
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- Date Issued: 2005
An investigation of female leaders' perceptions of organisational culture and leadership in a Catholic High School
- Authors: Jean-Louis, Lily-Claire Virginie
- Date: 2005
- Subjects: Catholic schools -- South Africa -- Administration School management and organization -- South Africa Educational leadership -- South Africa Corporate culture -- South Africa Women school administrators -- South Africa
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1625 , http://hdl.handle.net/10962/d1003507
- Description: For the past thirty years, leadership theories have focused on the importance of the individual within the school organisation. The shared assumptions and beliefs of the individuals working in the same organisation shape the school’s organisational culture, and organisational culture is a salient factor which should be considered when understanding educational leadership. The focus of my study is to explore the relationship between organisational culture and leadership. In the same context, new approaches to the study of leadership have explored the issue of gender in leadership. Female leadership studies - the second focus of this study - seek not only to restore the place of the individual but also argue a place for women in educational leadership. Based in the interpretive paradigm, this is a case study of a Catholic all-girl secondary school called the Loreto Convent School of Pretoria. Historically, the Loreto schools have aimed at promoting and empowering girls’ education and female leadership. It was therefore an appropriate site in which to explore organisational culture and its relationship with leadership, particularly female leadership. I purposefully chose three of the school’s female leaders - the school’s principal, the High school Head of Department and the High school head girl - focusing on their perceptions and experiences of their leadership and the school’s culture. My research findings show that an understanding of the relationship between organisational culture and leadership cannot be complete without acknowledging the importance of the leader as an individual, with his/her personal background and values, taking into account gender as well as the multiple roles that the individual has in society. Furthermore, the ‘humane’ characteristic of educational leadership leads to an understanding that the leader is often confronted with conflicting situations where he/she is caught between personal/organisational values and the need to achieve the task. Finally, my findings show that contemporary leaders are now called upon to work and participate in the promotion of social justice in order to fight against society’s socio-economic inequality and improve the quality of education and life.
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- Date Issued: 2005
An investigation of hair modelling and rendering techniques with emphasis on African hairstyles
- Authors: Patrick, Deborah Michelle
- Date: 2005 , 2013-10-17
- Subjects: RenderMan , Hairstyles -- Africa , Hairstyles -- Computer simulation -- Africa , Hairdressing of Black people , Computer graphics
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4639 , http://hdl.handle.net/10962/d1006561 , RenderMan , Hairstyles -- Africa , Hairstyles -- Computer simulation -- Africa , Hairdressing of Black people , Computer graphics
- Description: Many computer graphics applications make use of virtual humans. Methods for modelling and rendering hair are needed so that hairstyles can be added to the virtual humans. Modelling and rendering hair is challenging due to the large number of hair strands and their geometric properties, the complex lighting effects that occur among the strands of hair, and the complexity and large variation of human hairstyles. While methods have been developed for generating hair, no methods exist for generating African hair, which differs from hair of other ethnic groups. This thesis presents methods for modelling and rendering African hair. Existing hair modelling and rendering techniques are investigated, and the knowledge gained from the investigation is used to develop or enhance hair modelling and rendering techniques to produce three different forms of hair commonly found in African hairstyles. The different forms of hair identified are natural curly hair, straightened hair, and braids or twists of hair. The hair modelling techniques developed are implemented as plug-ins for the graphics program LightWave 3D. The plug-ins developed not only model the three identified forms of hair, but also add the modelled hair to a model of a head, and can be used to create a variety of African hairstyles. The plug-ins significantly reduce the time spent on hair modelling. Tests performed show that increasing the number of polygons used to model hair increases the quality of the hair produced, but also increases the rendering time. However, there is usually an upper bound to the number of polygons needed to produce a reasonable hairstyle, making it feasible to add African hairstyles to virtual humans. The rendering aspects investigated include hair illumination, texturing, shadowing and antialiasing. An anisotropic illumination model is developed that considers the properties of African hair, including the colouring, opacity and narrow width of the hair strands. Texturing is used in several instances to create the effect of individual strands of hair. Results show that texturing is useful for representing many hair strands because the density of the hair in a texture map does not have an effect on the rendering time. The importance of including a shadowing technique and applying an anti-aliasing method when rendering hair is demonstrated. The rendering techniques are implemented using the RenderMan Interface and Shading Language. A number of complete African hairstyles are shown, demonstrating that the techniques can be used to model and render African hair successfully. , GNU Ghostscript 7.07
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- Date Issued: 2005
An investigation of how Kampala teenagers who read Straight talk negotiate HIV/AIDS messages
- Authors: Kaija, Barbara Night Mbabazi
- Date: 2005
- Subjects: AIDS (Disease) -- Uganda -- Kampala Straight talk AIDS (Disease) -- Social aspects -- Uganda -- Kampala AIDS (Disease) in adolescence -- Uganda -- Kampala Teenagers -- Diseases -- Uganda -- Kampala AIDS (Disease) -- Study and teaching AIDS (Disease) in mass media Teenagers -- Sexual behavior -- Uganda -- Kampala AIDS (Disease) -- Prevention -- Uganda -- Kampala
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3440 , http://hdl.handle.net/10962/d1002894
- Description: This study is a qualitative ethnographic investigation of how teenagers in Kampala, Uganda, who read the HIV/AIDS publication aimed at adolescents, Straight Talk, negotiate HIV/AIDS messages. It seeks to establish to what extent these secondary school teenagers accept the key messages (known as ABC; Abstain, Be faithful or use a Condom) and understand the factual aspects of the messages about HIV/AIDS, its process of transmission and prevention. It also seeks to probe how the lived realities of the teenagers affect their particular negotiations of the HIV/AIDS messages. It includes a focus on how proximity to HIV/AIDS, gender and family economic disposition might affect teenagers, negotiation of the HIV/AIDS meanings. To investigate the respondents’ reception of HIV/AIDS messages, the study employed focus groups that consisted of two stages, namely the ‘news game’ and group discussions. In the ‘news game’ stage (Philo, 1990; Kitzinger, 1993) the teenage participants were required to produce a version of a one-page copy of an HIV/AIDS newspaper targeting teenagers. In the second stage of the focus group a structured discussion probed the teenagers’ negotiation of the HIV/AIDS media messages. In the news game, the teenagers on the whole reproduced the key Straight Talk HIV/AIDS messages ‘Abstain, Be faithful or use a Condom’ and also images showing the effects of HIV/AIDS but featured fewer images depicting the factual aspects of HIV/AIDS process of transmission and risky behaviour. In the structured discussion that followed the news game, it was evident that not all the teenagers necessarily believed the messages they produced. In spite of producing the ABC Straight Talk messages, some of them were uncertain and confused about the absolute safety of the condom because of fears that they were either porous, expired or would interfere with sexual pleasure. Secondly, though many of the teenagers in the study reproduced images that showed that they consider marriage as desirable and talked about their desire to abstain from sex till marriage, a considerable number think abstinence is not achievable due to competing values. Thirdly, the participant teenagers could differentiate between HIV and AIDS but many did not realise that with the advent of anti-retroviral drugs even people who have AIDS can look normal. In spite of repeating the Straight Talk message that “no one was safe” and being aware of the risky behaviour that their fellow teenagers get involved in, the teenagers seemed to think that their age cohort is safe from HIV and it is the adults who are likely to infect them. The study findings further indicate that the teenagers’ lived experience at times influence their negotiation of HIV/AIDS media messages. This was probed in terms of economic standing, gender and proximity to HIV/AIDS. In relation to gender one surprising discovery was that certain girls in the study feared getting pregnant more than getting HIV/AIDS. The study finally suggests that these findings are of significance for designing future media initiatives in relation to HIV/AIDS.
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- Date Issued: 2005
An investigation of information security in small and medium enterprises (SME's) in the Eastern Cape
- Authors: Upfold, Christopher Tennant
- Date: 2005
- Subjects: Small business -- South Africa -- Eastern Cape Computer security -- South Africa Information technology -- South Africa -- Eastern Cape Management information systems -- South Africa -- Eastern Cape Computer security -- Standards -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:727 , http://hdl.handle.net/10962/d1003847
- Description: Small and Medium Enterprises (SME’s) embrace a wide range of information systems and technology that range from basic bookkeeping and general purpose office packages, through to advanced E-Business Web portals and Electronic Data Interchange (EDI). A survey, based on SABS ISO/IEC 17799 was administered to a select number of SME’s in the services sector, in the Eastern Cape. The results of the survey revealed that the level of information security awareness amongst SME leadership is as diverse as the state of practice of their information systems and technology. Although a minority of SME’s do embrace security frameworks such as SABS ISO/IEC 17799 or the International equivalent, BS7799, most SME leaders have not heard of security standards, and see information security as a technical intervention designed to address virus threats and data backups. Furthermore, there are several “stripped-down” standards and guidelines for SME’s, based mostly on SABS ISO/IEC 17799, but designed as streamlined, more easily implemented options. Again, these “lighter” frameworks are scarcely used and largely unknown by SME’s. Far from blaming SME leadership for not understanding the critical issues surrounding information security, the research concludes that SME leadership need to engage, understand and implement formal information security processes, failing which their organisations may be severely impacted by inadvertent threats / deliberate attacks on their information systems which could ultimately lead to business failure.
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- Date Issued: 2005
An investigation of instructional leadership in a Namibian teacher training college
- Authors: Alexander, Christa Henriette
- Date: 2005
- Subjects: Windhoek College of Education Educational leadership -- Namibia Education -- Namibia Teachers -- Training of -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1634 , http://hdl.handle.net/10962/d1003516
- Description: This thesis investigates how instructional leaders at the Windhoek College of Education (in Namibia) make sense of their roles. The Windhoek College of Education (WCE) was selected for this study because that is where I work, therefore it would be easy to observe some of the responses provided by the interviewees. It was also observed that instructional leadership is little researched in Namibia and hence study would contribute towards understanding the various perceptions that instructional leaders have of their roles. There is a need for information about the skills and tasks required to support practices of instructional leadership so that the best possible instruction can be provided. The thesis examines and presents such skills. A qualitative research framework, in particular an interpretative approach was used for the study. As my research is concerned with people’s perceptions, it is located in the interpretative paradigm. Semi-structured, open-ended interview questions were asked in order to gather information on how the participants make meaning of their roles as instructional leaders. The sample for the study consisted of eleven instructional leaders over different levels, i.e., executive leaders, leaders on middle-management level and leaders on classroom-instructional level. The findings indicated a narrow view of instructional leadership at the college. Factors contributing to this narrowness are addressed, e.g., the way concepts such as delegation, guidance and monitoring/supervision are perceived. The findings also addressed certain expectations that are needed from instructional leaders in order to ensure efficiency in their practice. The study concludes by recommending alternative, expansive ways of thinking about instructional leadership.
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- Date Issued: 2005
An investigation of local community contributions to the Malawi College of Fisheries curriculum: a case study focussing on the Chambo fishery
- Authors: Kachilonda, Dick Daffu Kachanga
- Date: 2005
- Subjects: Malawi College of Fisheries -- Curricula Fishery management -- Study and teaching Fishery management -- Malawi Fisheries -- Malawi Fishes -- Nyasa, Lake
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1857 , http://hdl.handle.net/10962/d1004537
- Description: The aim of the study was to investigate local community contributions to the existing Malawi College of Fisheries curriculum with a focus on Chambo fishery. Chambo fish (Oreochromis species) is the most favoured fish in Lake Malawi. Chambo catches have declined over the years. Responding to the declining catches, the Fisheries Department is engaged in a number of management options to address the issues. Most of these management options are governed by scientific recommendations and do not consider the socio-economic situation of the people who are dependent on fishery. This approach to fishery has influenced the Malawi College of Fisheries curriculum. The existing curriculum is product-centred, developed by a consultant. During the development of the curriculum, there was little consultation with the lecturers and no consultation with the local communities who are using the resource. The fishing communities have been fishing for a long time and have acquired knowledge, skills and experience worth investigating for its potential role in improving the existing curriculum. Through the use of interviews, focus group discussions and workshops with local communities local knowledge was identified for inclusion into the curriculum. A review of the existing curriculum revealed that it has primarily technical focus, grounded in the protection, control and management of the fish stocks, while the local knowledge has a practical focus based on existing practices and requiring an understanding of the sources of the issues. There is also more emphasis on a historical perspective and the context in which fishing practices take place at the moment. It was evident from the study that local communities have much of knowledge, skills and experience gained over the years of fishing , and if properly utilised, it can improve the MCF curriculum. I therefore recommend in this study that the curriculum be reviewed in order to integrate and draw on the local knowledge through a deliberative and participatory process between the local communities and the government so that it addresses the needs of the local communities and improves the training of the extension workers.
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- Date Issued: 2005
An investigation of the development and adoption of educational metadata standards for the widespread use of learning objects
- Authors: Krull, Greig Emil
- Date: 2005
- Subjects: Metadata , Internet in education , Web databases , Education -- Standards , Educational technology , Computer-assisted instruction
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:1142 , http://hdl.handle.net/10962/d1002771 , Metadata , Internet in education , Web databases , Education -- Standards , Educational technology , Computer-assisted instruction
- Description: This research investigates the development and adoption of educational metadata standards for the widespread use of learning objects. Learning objects, metadata, the related IEEE standard and the various application profiles derived from the standard are discussed. A number of standards and specifications for educational metadata used to describe learning objects are explored, namely the Dublin Core, IMS, SCORM, ARIADNE, CanCore and the UK LOM Core. Three metadata editors and the experience with using one of them, RELOAD, is described. These educational metadata specifications are used in a practical metadata implementation scenario and the experiences are extrapolated to derive a localised instance of the generic IEEE standard. A new application profile is proposed, “RU LOM Core”, for the South African higher education context. Some existing results are confirmed about the complexity of using the IEEE standard and it is demonstrated that it is possible to instantiate the standard for South African conditions. The results are largely qualitative and based on practical experience. However, the results concur with results from related research. Although the development of an application profile is certainly not new, the development of RU LOM Core illustrates that the IEEE standard, developed largely within the northern hemisphere, can be adapted to work in the South African scenario. RU LOM Core has been developed for the South African higher education environment and takes linguistic and cultural diversity and the low rate of technological literacy into consideration. The lessons learned and the proposed LOM core can be built upon in further research and collaboration to use and support the use of such standards within South Africa.
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- Date Issued: 2005
An investigation of the experiences and perceptions of teachers with regards to staff development in a Namibian secondary school
- Authors: Nasima, Gideon Emmanuel
- Date: 2005
- Subjects: Education -- Namibia Teachers -- In-service training -- Namibia School management and organization -- Namibia School principals -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1649 , http://hdl.handle.net/10962/d1003532
- Description: Staff development (SD) is regarded as an important process, both for the professional growth of teachers and the organizational development of schools. The literature on SD uses the concepts of ‘SD’, ‘professional development’ and ‘in-service training of teachers’ interchangeably. The purpose of this study is to investigate the teachers’ experiences and perceptions of SD practices in a Namibian secondary school. This qualitative case study was carried out at the school where I am teaching. Two methods were used to collect the data, namely a blend of semi-structured and unstructured interviews with three teachers and one focus group interview with five teachers. The analysis of the data collected was carried using the method suggested by Taylor and Bogdan (1998) which includes discovery, coding and discounting. These concepts are discussed in Chapter Three. The main finding of this research regards SD at the school as mainly in line with the traditional view. The study also made three other unusual findings that differ from the traditional view of SD held at the school. First, the principal’s role as a human resource manager of SD; second the pastoral role of a principal in SD and third the role of teachers’ unions in SD. All these findings are important for SD practices in schools and for further research because little is known in the current literature on SD. Finally, this study proposes further research to develop an organizational development (OD) cycle of problem solving to help create an internal policy on SD, which is currently nonexistent at the school.
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- Date Issued: 2005
An investigation of the factors that influence Grahamstown East grade 12 learners to aspire to higher education : a case study
- Authors: Burns-Ncamashe, Zimasa Nomsawezulu Ancilla
- Date: 2005
- Subjects: Education -- South Africa -- Grahamstown -- Case studies , Education, Secondary -- South Africa -- Grahamstown -- Case studies , Education, Higher -- South Africa -- Grahamstown -- Case studies , Student aspirations -- South Africa -- Grahamstown -- Case studies , High school graduates -- South Africa -- Attitudes -- Case studies , Vocational interests -- South Africa -- Grahamstown -- Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1650 , http://hdl.handle.net/10962/d1003533 , Education -- South Africa -- Grahamstown -- Case studies , Education, Secondary -- South Africa -- Grahamstown -- Case studies , Education, Higher -- South Africa -- Grahamstown -- Case studies , Student aspirations -- South Africa -- Grahamstown -- Case studies , High school graduates -- South Africa -- Attitudes -- Case studies , Vocational interests -- South Africa -- Grahamstown -- Case studies
- Description: This research is an investigation into the factors that influence the decisions of grade 12 learners from Grahamstown East disadvantaged communities to pursue higher education. Research on learner aspirations has largely focused on access to higher education and little or no attention has been has been paid to the enabling or limiting factors and what can be done to increase the numbers of learners from disadvantaged communities who enrol at higher education institutions. This study aims to fill that gap. The research was a qualitative case study located in the interpretive paradigm. The data was gathered using questionnaires and focus group interviews for grade 12 learners. Individual interviews were conducted with the parents of the grade 12 research participants, educators and the school management team. Observation and documentary evidence from school documents were also used for data collection. The data were analysed using systematic patterning, were interpreted, and given meaning linking it to the literature surveyed. The main findings indicate that a number of enabling factors that influence grade 12 learners to pursue higher education co-exist with limiting factors. Recommendations arising from the main findings are presented and the limitations of the research are identified. Areas for possible further research in strengthening learner support so as to increase the numbers of learners who qualify for higher education and to enable the learners from disadvantaged communities to realise their aspirations, are suggested.
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- Date Issued: 2005
An investigation of the role of news values in the selection of news sources in a contemporary third world newspaper: a case study of the Daily Nation newspaper
- Authors: Kisuke, Connie Syomiti
- Date: 2005
- Subjects: Daily Nation (Nairobi, Kenya) , Government and the press -- Africa , Reporters and reporting , Mass media -- Political aspects -- Africa , Newspapers -- Africa , Journalism -- Social aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3446 , http://hdl.handle.net/10962/d1002900 , Daily Nation (Nairobi, Kenya) , Government and the press -- Africa , Reporters and reporting , Mass media -- Political aspects -- Africa , Newspapers -- Africa , Journalism -- Social aspects
- Description: News in our contemporary newspapers has come to be associated more and more with what the elites do and say. Both their deeds and misdeeds are treated as newsworthy events and in the process they become newsmakers, both actors and sources of news. Even when they are not directly involved in news events they are sought out by journalists to validate those events and to interpret the social reality to the readers as news sources. This study is about the selection of news sources in the Daily Nation, a contemporary, independent newspaper based in Nairobi, Kenya. In this study, I set out to unravel the complex processes that underlie newsmaking and source selection. This study is informed by the theory of news values and the paradigm of the role of media in democracy. Based on qualitative interviews, observations and content analysis of the front-page stories, it investigates the process of news and source selection in front-page stories. Through these approaches, I established that news values are significant criteria that inform journalists in both the selection of front-page news stories and the sources of these stories. I also established that social values of the society in which this newspaper operates are heavily embedded in the news. For example, the journalists preferred male politicians as sources of news in the front-page stories to women, and the elites to ordinary people, and this reflected on the social structures and cultural norms that are prevalent in this society. This study, further, established that the news values of this newspaper share commonly with the Western news media in terms of journalistic conventions and ways of interpreting the social reality in the news. Ideally, the newspaper embraces the principles of democracy in news reporting, but in practice it does not satisfactorily adhere to the full requirements of its democratic role in terms of source selection. The democratic principles in news reporting require, among other things, that the newspaper should allow a diversity of views in the news, representing various groups that are found in real society including the elites, non-elites, women, ordinary people and minorities. In the case of the Daily Nation, a tiny group of elite male professional politicians made up the largest majority of its front-page news sources.
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- Date Issued: 2005
An organisation development intervention in a previously disadvantaged school in the Eastern Cape
- Authors: Mitchell, Pauline
- Date: 2005
- Subjects: Educational change -- South Africa -- Eastern Cape Education and state -- South Africa -- Eastern Cape Education -- Social aspects -- South Africa -- Eastern Cape Education -- South Africa -- Eastern Cape School improvement programs -- South Africa -- Eastern Cape -- Case studies Education -- Aims and objectives -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1682 , http://hdl.handle.net/10962/d1003565
- Description: “We often spend too much time coping with problems along our path that we forget why we are on that path” Peter Senge This study describes and analyses the implementation of Organisation Development (OD) to a previously disadvantaged school. OD is a relatively new method of planned change in South Africa. Unlike more traditional change initiatives, OD promotes collaboration; it tries to involve all members of an organisation in problem solving and decision-making. It is an applied behavioural science discipline dedicated to improving organisations and the people in them. Previously disadvantaged schools in South Africa continue to be disadvantaged. Ten years after the introduction of democracy there have been few changes in some of these schools and some seem to be getting worse. This study was an attempt to introduce a process of planned change to one such school. Since 1994 many changes have been imposed on our schools with new curricula, increased class sizes, changes in systems of assessment and teaching methods and the abolishment of past procedures such as corporal punishment. Teachers have had little say in any of these changes and this has resulted in resistance, resignation, frustration and in many cases a lack of ability to cope. OD was introduced to Acacia High School in the form of a Survey Data Feedback (SDF). An action research process followed and a diagnosis was made followed by action planning and then the execution of a plan. My study follows this process and the implementation of the plan describing its successes. Sadly change was not sustained and I highlight some of the challenges that face the school in order to bring about real long-term improvement in the culture of learning and teaching.
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- Date Issued: 2005
Animal suffering in factory farming and the best way to prevent it
- Authors: Watkins, Gareth
- Date: 2005
- Subjects: Vegetarianism -- Moral and ethical aspects Food animals -- Moral and ethical aspects Animal rights Animal welfare Animal welfare -- Moral and ethical aspects Vegetarianism
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2728 , http://hdl.handle.net/10962/d1003736
- Description: This thesis moves beyond the traditional approaches of how we ought to treat animals, and instead concentrates on the best strategy for preventing animal suffering in the farming industry. Chapter 1 considers the question of how we can know that animals feel pain, and concludes not only that it is rational to believe that they can, but also that this is a significant fact. Chapter 2 then analyses one possible strategy for helping to prevent animal suffering, namely demi-vegetarianism. For a number of reasons, however, this strategy is found to be flawed, therefore Chapter 3 analyses a second possible strategy, namely vegetarianism, and concludes that this is, in fact, the best strategy for helping to prevent animal suffering in the farming industry.
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- Date Issued: 2005
Aspects of the ecology and management of the Soupfin shark (Galeorhinus galeus) in South Africa
- Authors: McCord, Meaghen Erica
- Date: 2005
- Subjects: Soupfin shark -- South Africa , Soupfin shark -- Ecology -- South Africa , Fishery management -- South Africa , Shark fisheries -- Management -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5223 , http://hdl.handle.net/10962/d1005066 , Soupfin shark -- South Africa , Soupfin shark -- Ecology -- South Africa , Fishery management -- South Africa , Shark fisheries -- Management -- South Africa
- Description: Global trends in teleost fisheries indicate significant population declines. Thus, alternative fisheries are being developed to meet the growing economic and nutritional demands of the expanding human population. Recently, it has been established that elasmobranch fisheries may fulfill these demands. As many elasmobranchs possess life-history characteristics that make them particularly vulnerable to overfishing, it is imperative to develop management strategies prior to the inception of these fisheries to ensure sustainable resource utilisation. In South Africa, elasmobranchs have been commercially exploited since the 1930s. Although generally considered an under-exploited resource, the potential for growth within these fisheries has been recognized. In 2005, the commercial shark fishery will undergo a transition from medium to long-term rights allocations. This represents an ideal opportunity for scientists and managers to develop precautionary species-specific management plans for commercially exploitable elasmobranch species. The soupfin shark (Galeorhinus galeus) is one of the principal target species in South Africa’s shark fisheries. Given its inherent susceptibility to overexploitation, G. galeus was selected as a management priority by South Africa’s regional fisheries organisation. The purpose of this study was to examine and describe the stock status of G. galeus in South Africa, and to develop a precautionary fishery management plan to ensure the sustainability of this resource. Age, growth, and mortality calculations for G. galeus were made from research survey data collected between 1996 and 1999. A small sample size precluded independent analyses of females. The maximum recorded age for G. galeus was 33 years. Estimated von Bertalanffy growth parameters from observed length-at-age for males and combined sexes were: L∞ 1542.8 mm TL, K 0.21 year⁻¹ , t₀ -2.79 year⁻¹ and L∞ 1560.3 mm TL, K 0.19 year¹, t₀ -3.03 year⁻¹, respectively. The age-at-50% maturity was determined to be 6 years, corresponding to 1011 mm TL for males and 1100 mm TL for combined sexes. Natural mortality was calculated as 0.126 yr⁻¹. The rate of instantaneous total mortality was calculated as 0.27 yr⁻¹. Catch trend analysis showed that catches and CPUE of G. galeus are increasing in the demersal longline fishery, and decreasing in the handline fishery. Decreasing catches and CPUE were observed in fishery-independent research survey data. The status of the soupfin shark stock was modelled using per-recruit analysis. The SB/R model indicated the soupfin shark is being optimally exploited and spawner biomass is at 43% of preexploitation levels. Current fishing levels ( F = 0.14 yr⁻¹) approximate the Fsb₄₀ level (F = 0.17 yr¹); thus, an increase in fishing pressure may lead to stock collapse. It was determined that the current age-at-capture (7.9 years) should be increased to 10 years, or 1420 mm TL, to maximize yield and minimize the possibility of recruitment failure. The results of this study indicate a need for immediate scientific and management intervention in South Africa’s soupfin shark fishery. An assessment report and fishery management plan for G. galeus was compiled, and several management options were proposed. These include the implementation of licence and size restrictions, as well as seasonal/area closures. The potential for an experimental gillnet fishery should be investigated.
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- Date Issued: 2005