Novel approaches to the monitoring of computer networks
- Authors: Halse, G A
- Date: 2003
- Subjects: Computer networks , Computer networks -- Management , Computer networks -- South Africa -- Grahamstown , Rhodes University -- Information Technology Division
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4645 , http://hdl.handle.net/10962/d1006601
- Description: Traditional network monitoring techniques suffer from a number of limitations. They are usually designed to solve the most general case, and as a result often fall short of expectation. This project sets out to provide the network administrator with a set of alternative tools to solve specific, but common, problems. It uses the network at Rhodes University as a case study and addresses a number of issues that arise on this network. Four problematic areas are identified within this network: the automatic determination of network topology and layout, the tracking of network growth, the determination of the physical and logical locations of hosts on the network, and the need for intelligent fault reporting systems. These areas are chosen because other network monitoring techniques have failed to adequately address these problems, and because they present problems that are common across a large number of networks. Each area is examined separately and a solution is sought for each of the problems identified. As a result, a set of tools is developed to solve these problems using a number of novel network monitoring techniques. These tools are designed to be as portable as possible so as not to limit their use to the case study network. Their use within Rhodes, as well as their applicability to other situations is discussed. In all cases, any limitations and shortfalls in the approaches that were employed are examined.
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- Date Issued: 2003
Nursing in transition: negotiating the experience: an exploration of the impact of the aids pandemic on the subjective work experiences of peri-urban nurses
- Authors: Brown, Lisa Joy
- Date: 2003
- Subjects: AIDS (Disease) -- Nursing -- South Africa , AIDS (Disease) -- Nursing -- Psychological aspects , Nurses -- Job stress -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3252 , http://hdl.handle.net/10962/d1015962
- Description: A substantial amount of international research exists examining the impact of HIV/AIDS on health care workers. However, the impact of HIV/AIDS on nursing staff in South Africa has been relatively neglected. The primary objective of this study was to examine the impact of the AIDS pandemic on the subjective work experiences of peri-urban nurses in South Africa. The study explored the relationship between external changes in the nurses' working environment and their internal psychological responses for negotiating this change. A focus group of eight nurses was conducted, followed by indepth individual interviews with three group members. A grounded theory method was utilised to process and analyse the data. The research showed that nurses experience two forms of change. It was suggested that nurses respond to external changes in a manner designed to maximise their control and sense of meaning in an unpredictable environment. This accommodation involves the restoration of an internal psychological equilibrium through a process of balancing positive and negative experiences. The attainment of such an acceptable equilibrium may allow for diminished stress, increased satisfaction or fulfilment and the validation of personal and professional significance.
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- Date Issued: 2003
On the use of metabolic rate measurements to assess the stress response in juvenile spotted grunter, Pomadasys commersonnii (Haemulidae, Pisces)
- Authors: Radull, John
- Date: 2003
- Subjects: Fishes -- Metabolism Fishes -- Physiology Pomadasys -- Physiology Grunts (Fishes) -- Physiology Stress (Psychology) Stress (Physiology)
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5350 , http://hdl.handle.net/10962/d1007564
- Description: Quantitication of stress requires the use of a stress indicator that is easy to measure, and which can be readily interpreted in terms of the potential long-term effects to an organism. This study evaluates the suitability of metabolic rate as an indicator of the stress response in fish. By comparing the metabolic with the cortisol stress response, the most commonly used indicator of stress in fish, it was possible to assess the suitability of metabolic rate as a stress indicator. Changes in metabolic rate were used to predict the long-term effects of transport-related stressors. This study also detennined the baseline metabolic rates of the tish. The standard and the active metabolic rates of juvenile P. cummersonnii were 0.16 ± 0.02 (mean ± S.D, n = 6) mg O₂g⁻¹h⁻¹, and 0.56 ± 0.04 mg O₂g⁻¹h⁻¹, respectively, whereas the routine metabolic rate for the fish was 0.25 ± 0.03 mg O₂g⁻¹h¹. The relationship between metabolic rate and body weight was described by the equation ϺO₂ = 0.64 W⁻°·³⁸. 24-h oxygen consumption measurements showed that juvenile P. commersonnii exhibited diel rhythmicity in oxygen consumption rate, the higher rates occurring at night and the lower rates during the daytime. The higher nocturnal metabolic activity may have been due to increased activity induced by an endogenous rhythm related to feeding. Diel rhythmicity has direct implications for the measurement of baseline metabolic rates since it could result in overestimation or underestimation of these rates. 24-h continuous oxygen consumption measurements enabled the detection of the rhythmicity in oxygen consumption rate, and thereby ensured a greater degree of accuracy in the estimation of these parameters. The metabolic stress response in juvenile P. commersonnii was best described by the equation, y = -0.0013 x² + 0.0364 x ÷ 0.3052, where x = time after application of stressor, and y = oxygen consumption rate. Using the derivative of this equation, the metabolic stress response was estimated to peak approximately 14 min after application of a simulated capture and handling stressor. Oxygen consumption increased by about 300 % as a result of the stress. Approximately 15 min after application of a similar stressor, plasma cortisol levels in stressed fish was 200 % higher than baseline levels. However, cortisol levels in fish sampled 30 min after the disturbance was similar to the baseline cortisol levels, indicating that full recovery had occurred. Although the patterns in the metabolic and cortisol stress responses were similar, metabolic rate could be measured continuously, thereby ensuring accurate interpretation of the data. Furthermore, increases in metabolic rate during the stress response are a culmination of physiological events from the primary to the tertiary levels of biological organization and are, therefore, easier to interpret in terms of long-term effects on the fish. Different transportation procedures elicited variable degrees of stress in juvenile P. commersonnii. The cost of metabolism attributed to the effects of capture and handling was twice as much as that attributed to acute temperature elevation. Acute temperature decrease resulted in a signiticant reduction in the oxygen consumption rate (ANOVA, P < 0.05). Oxygen consumption by the fish was not affected by fish density (ANOVA: F = 2.002, P = 0.5), or by oxygen depletion at dissolved oxygen concentrations above the critical level. Below this level, however, oxygen consumption decreased linearly with further decrease in dissolved oxygen concentration. These results showed that the highest energetic cost to juvenile P. commersonnii was incurred as a result of capture and handling. The results also showed that by subjecting fish to different stressors, it was possible to categorize them according to their relative metabolic costs to the fish. At 25º C, the effective concentration of 2-phenoxyethanol to fully anaesthetize (Stage IV, McFarland 1960) juvenile P. commersonnii was 0.4 ml l⁻¹ and the most appropriate concentration for deep sedation (Stage II, McFarland 1960) of the fish for at least 24 h was 0.2 ml l⁻¹. A maximum of 3 minutes was required by the fish to recover from the effects of the anaesthetic. There was no correlation between fish weight and the rate of induction of anaesthesia (r² = 0.001, p = 0.3). At the peak of the metabolic stress response, oxygen consumption was twice as high in the un-anaesthetized fish compared to the fish anaesthetized after the application of the simulated capture and handling stressor, suggesting that anaesthetization with 2-phenoxyethanol may have reduced the effect of the disturbance on the fish. Similar oxygen consumption rates for the fish anaesthetized prior to capture and the non-stressed fish suggested that the increases in metabolic rate could be linked to the struggling associated with attempts by fish to escape from the perceived stressor. Anaesthetization of juvenile P. commersonnii with 0.3 ml l⁻¹ 2-phenoxyethanol resulted in a more than 200 % increase in plasma cortisol concentration. The elevated levels of plasma cortisol in the anaesthetized fish suggested a manifestation of 2-phenoxyethanol as a stressor. At the time of capture, cortisol levels in fish that were anaesthetized prior to capture were the same as those measured in the disturbed fish at the peak of the stress response (ANOVA, p = 0.95), suggesting that the anaesthetized fish were already experiencing considerable stress at the time they were captured. Undisturbed juvenile P. commersonnii that were anaesthetized for 1 h also had cortisol levels that were five times higher than those measured in undisturbed-unanaesthetized fish, indicating that the duration of exposure to the anaesthetic had a significant effect on plasma cortisol levels. The results presented in this study demonstrate the usefulness of metabolic rate as an indicator of acute stress in fish. This was achieved by comparing the metabolic and the cortisol stress responses. The ease and accuracy with which oxygen consumption of fish could be measured made it possible to measure the stress response more accurately than by plasma cortisol concentration. It was also possible to monitor metabolic rate continuously over a long duration using polarographic oxygen sensors, thus enabling a better evaluation of the stress response. These results, thus, suggest that metabolic rate measurements could be a more practical way to quantify the effects of acute stressors on juvenile fishes. By detailing the profile of the metabolic stress response in P. commersonnii, this study makes a contribution towards understanding the physiological effects of stress in fishes. The study also contributes towards the quantification of baseline metabolic rates of this species under captivity. This study also contributes towards understanding the effects of 2-phenoxyethanol on the stress physiology of fish. By anaesthetizing fish under different conditions of stress, it was possible to evaluate the effect of 2-phenoxyethanol on the metabolic stress response. The ability of 2-phenoxyethanol to reduce physical activity of the fish, and thereby reduce the impact of acute stress on the metabolic stress response, makes it a good agent for the mitigation of stress during the capture and handling of fish. However, the increase in plasma cortisol concentration during prolonged anaesthetization using this drug suggests that the anaesthetic might be a stressor to fish and may, therefore, not be suitable for long-term sedation.
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- Date Issued: 2003
Over-expression, purification and biochemical characterisation of trypanosomal heat shock protein
- Authors: Edkins, Adrienne Lesley
- Date: 2003
- Subjects: Heat shock proteins , Heat shock proteins -- Structure activity relationships
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4106 , http://hdl.handle.net/10962/d1011736 , Heat shock proteins , Heat shock proteins -- Structure activity relationships
- Description: The molecular chaperone process of assisted protein folding, characteristic of members of the Heat Shock Protein 70 kDa (Hsp70) and Heat Shock Protein 40kDa (Hsp40) families, is essential for cytoprotection in stressful cellular conditions. Examples of such conditions are heat shock or invasion by pathogens. The Hsp70/Hsp40 process of assisted protein folding is dependent on ATP (governed by the intrinsic ATPase activity of Hsp70) and the ability of molecular chaperones to recognise and bind non-native protein conformations. Here, we analyse and attempt to characterise the molecular chaperone activity of an inducible, cytoplasmic Hsp70 (TcHsp70) from Trypanosoma cruzi and its interactions with its potential partner Hsp40s, Tcj 1, Tcj2, Tcj3 and Tcj4. A bioinformatic analyses of the primary sequences of the trypanosomal proteins revealed that they all contained the canonical domains that define other members of the Hsp70 and Hsp40 family. Tcj2 and Tcj4 showed deviations from the consensus sequence in their substrate binding regions, which may have implications for their substrate binding specificities. TcHsp70, Tcj 1, Tcj2, Tcj3 and Tcj4 were over-expressed recombinantly as 6xHis-tag fusion proteins in Escherichia coli. His-TcHsp70, Tcjl-His and His-Tcj2 were successfully purified by Nickel-affinity chromatography for functional analyses to assess the molecular chaperone activity of His-TcHsp70 in terms of its ATPase activity and substrate binding ability. The basal ATPase activity of His-TcHsp70 was determined as 40 nmol Pi/min/mg, significantly higher than that reported for other Hsp70s. This basal ATPase activity was stimulated to a maximal level of 60 nmol Pi/min/mg in the presence of His-Tcj2 and a model non-native substrate, reduced carboxymethylated αx-lactalbumin (RCMLA). Using native polyacrylamide gel electrophoresis and Western analysis, His-TcHsp70 was shown to form discrete complexes when in the presence of Tcj 1- His, His-Tcj2 and/or RCMLA. These complexes potentially represent His-TcHsp70 - RCMLA or His-TcHsp70 - Tcj interactions, that may be indicative of chaperone activity. In vivo complementation assays showed that Tcj2, but not Tcj3, was able to overcome the temperature sensitivity of the ydjJ mutant Saccharomyces cerevisiae strain JJ160, suggesting that Tcj2 may be functionally equivalent to the yeast Hsp40 Ydj1.
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- Date Issued: 2003
Paranoid metaphors: an examination of the discursive, theoretical and sometimes personal, interaction between the psychoanalyst, Jacques Lacan, the surrealist, Salvador Dali, and the English poet, David Gascoyne
- Authors: De Klerk, Eugene
- Date: 2003
- Subjects: Paranoia , Lacan, Jacques, 1901-1981 , Dali, Salvador, 1904-1989 , Gascoyne, David, 1916-2001
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2192 , http://hdl.handle.net/10962/d1002234 , Paranoia , Lacan, Jacques, 1901-1981 , Dali, Salvador, 1904-1989 , Gascoyne, David, 1916-2001
- Description: This thesis examines the historical interaction of the psychoanalyst, Jacques Lacan, the surrealist, Salvador Dali, and the English poet, David Gascoyne. It traces the discursive, and sometimes personal, relationship between these figures which led to a psychoanalytic-based conception of paranoia that impacted on both surrealism and the surrealist-inspired poetry and theory of David Gascoyne. Furthermore it seeks to identify the potential ramifications of this conception of paranoia, and the artistic practice it engendered, for literary, Marxist and psychoanalytic theory.
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- Date Issued: 2003
Participants' perceptions of Computer-Mediated Communication: a case study of the Global Teenager Project
- Authors: Turyagyenda, Joy Kyarimpa
- Date: 2003
- Subjects: Global Teenager Project Computer networks -- Social aspects Communication Telematics Learning -- Technological innovations
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1687 , http://hdl.handle.net/10962/d1003570
- Description: The study outlines general trends evident in Computer-Mediated Communication (CMC), participants’ perceptions and the promotion of CMC across the curriculum in a South African Secondary School. This case study focuses on the Global Teenager Project (GTP), which started as a bi-national pilot project in April 1999 between secondary schools in South Africa and the Netherlands. The study sets out to investigate how well the GTP can be incorporated into the existing school curriculum through the teacherresearcher’s direct involvement in facilitating the project at a school where she is a fulltime teacher. The main purpose of the study is to review existing literature to establish how collaborative learning could be achieved through a CMC environment between teenagers from various countries based on the research done at an international level and link the practice at this school to the existing international trends. It was found that the GTP has great potential in enhancing collaborative learning within various learning areas at Nathaniel Nyaluza Secondary School (NNSS). Despite the usefulness of the GTP and the overwhelming enthusiasm learners displayed, its success at NNSS depended on the motivation of teachers and how easily the activities of the GTP could be incorporated within day-to-day teachers’ activities. , Hodgkinson, Cheryl
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- Date Issued: 2003
Patents, pills, poverty and pandemic: the ethical issues
- Authors: Brown, Walter
- Date: 2003
- Subjects: Kant, Immanuel, 1724-1804 -- Ethics , AIDS (Disease) -- Treatment -- South Africa -- Moral and ethical aspects , AIDS (Disease) -- Moral and ethical aspects , HIV infections -- South Africa , HIV infections -- Treatment -- South Africa -- Moral and ethical aspects , Social responsibility of business , Pharmaceutical industry -- South Africa -- Moral and ethical aspects
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2705 , http://hdl.handle.net/10962/d1002835 , Kant, Immanuel, 1724-1804 -- Ethics , AIDS (Disease) -- Treatment -- South Africa -- Moral and ethical aspects , AIDS (Disease) -- Moral and ethical aspects , HIV infections -- South Africa , HIV infections -- Treatment -- South Africa -- Moral and ethical aspects , Social responsibility of business , Pharmaceutical industry -- South Africa -- Moral and ethical aspects
- Description: This thesis argues that corporations qua corporations are moral agents sui generis and hence capable of being held morally responsible. I argue that corporations qua corporations are responsible for the actual and foreseen consequences of their actions. I analyse normative theories and the different proscriptive responsibilities they place on moral agents and hence corporations. I examine Kantianism, utilitarianism and virtue ethics. I argue for a unique normative ethical theory that incorporates reasoning from all three of the normative theories. I argue for a broad range of reasons to factor into deciding whether an act is ethical or not. One of the claims of this thesis is that ethical theories must incorporate an agent’s motivation, intention and character traits as relevant to deciding on whether an action is ethical or not. My thesis argues for an indispensable role for the virtues while at the same time incorporating impartial beneficence and universal rationality from utilitarianism and Kantianism. This position I, following the literature, refer to as moderate virtue theory. Having established corporate qua corporate responsibility I question the pharmaceutical corporation’s practice of patenting life saving medication during a state of pandemic in poor countries. The moderate virtue theory position prioritises contexts and the actual human condition and criticises normative theories that attempt to give universal, abstracted answers to ethical problems. It is for this reason and the current (2003) HIV/AIDS pandemic that I focus on a particular context. I examine the practice of patenting life saving medication within South Africa and argue, applying moderate virtue theory, that this act cannot be justified. I argue that a pharmaceutical corporation that patents life saving medication in South Africa cannot justify that action and thus is morally responsible for that action. I also argue that corporations patenting HIV/AIDS medication in South Africa have unethical motivations and intentions.
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- Date Issued: 2003
Patterns of early adolescent sex and implications for HIV/AIDS risk prevention : a contextual study in the Amatole Basin, Eastern Cape
- Authors: Ntlabati, Pumla L
- Date: 2003
- Subjects: Teenagers -- Sexual behavior , Teenagers -- Health and hygiene -- South Africa -- Eastern Cape , Teenagers -- Diseases -- South Africa -- Eastern Cape , Sexually transmitted diseases -- South Africa -- Eastern Cape , AIDS (Disease) -- South Africa -- Eastern Cape , AIDS (Disease) in adolescence -- South Africa -- Eastern Cape -- Attitudes , AIDS (Disease) -- Prevention -- South Africa --Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3176 , http://hdl.handle.net/10962/d1007814
- Description: This study involves an analysis of accounts of first and subsequent early sexual experiences in a deep rural area of the Eastern Cape in South Africa over the last forty years. Through interviews and focus group discussions, the enculturation of youth into sexual activity in the community of interest is explored. The study looks into sexual experiences from childhood, through early adolescence to adults of up to sixty five years old, allowing an analysis of the changing forms of sexual experimentation and sexual debut in this context. Contextual factors mediating these changes are explored, with special emphasis on the changing regulatory practices around early sexual experiences and the effect thereof on behaviors connected to HIV infection risk. Practices that were previously important mediators of sexual behavior were: anxiety about the social consequences of pregnancy, which was previously a significant disincentive to sexual intercourse; men's previous acceptance of the need to practice non-penetrative forms of sex and girls postponing sexual debut for as long as possible. All these were culturally endorsed, but are now noted to have changed due to changes in the regulatory practices surrounding youth sexuality. The context of early sexual experiences and the surrounding cultural practices have also changed significantly, and this needs to be taken into account in understanding receptivity to condom use messages. Implications for HIV/AIDS prevention are discussed. Among other interventions, the study describes a participatory, community-based, multi-sectoral approach that takes social conditions into account as a way of empowering the community to strengthen its response to the pandemic. This incorporates different sectors of the community, including youth, parents, religious and traditional leaders, and various other structures, services and institutions that make up the community.
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- Date Issued: 2003
People-centred development in practice: the case of the Zikhova-Ngqinisa Sidibene Woodlot Trust Project
- Authors: Pona, Faith Zolisa
- Date: 2003
- Subjects: Zikhova-Ngqinisa Sidibene Woodlot Trust Project , Rural development -- South Africa -- Eastern Cape , Rural development projects -- South Africa -- Eastern Cape -- Citizen participation , Woodlots -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3356 , http://hdl.handle.net/10962/d1007610 , Zikhova-Ngqinisa Sidibene Woodlot Trust Project , Rural development -- South Africa -- Eastern Cape , Rural development projects -- South Africa -- Eastern Cape -- Citizen participation , Woodlots -- South Africa -- Eastern Cape , Economic development projects -- South Africa -- Eastern Cape
- Description: This study addresses the question of people-centred development as a transformative aspect of the new South African development arena. The concept is defined as the involvement and active participation of people in the decision-making, evaluation and implementation of the development processes, It is one of the forms of democratisation which involves the decentralisaton of authority to the lower tiers of government. This study provides an analysis of the efficacy, relevance, advantages and disadvantages of people-centred development in the South African context. The Zikhoya-Ngqinisa Woodlot Trust Project was chosen as a case study, The reason was that through the process of devolution of the Department of Forestry and Water Affairs (DWAF), which involved the handing over of the management and financial resources of the small woodlots to the communities for their own benefit, the two villages, Zikhova and Ngqinisa, were given the Zikhova woodlot. The devolution of DWAF is one of the various forms of decentralisation that has given more autonomy to the lower tiers of government in the sense that the communities now have to satisfy their own needs. The main focus of the study was to identify and analyse constraints on the implementation of people-centred development specific to the Zikhova-Ngqinisa Woodlot Trust Project. Other interrelated aspects of people-centred development such as sustainability, community involvement and benefits of the project were also investigated and analysed. , KMBT_363
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- Date Issued: 2003
Pharmaceutical analysis and aspects of the quality control of St. John's Wort products
- Authors: Wild, Tracy Joy
- Date: 2003
- Subjects: Hypericum perforatum , Hypericum perforatum -- Analysis , Hypericum perforatum -- Therapeutic use , Hypericum perforatum -- Physiological effect , Flavonoids -- Analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3804 , http://hdl.handle.net/10962/d1003282 , Hypericum perforatum , Hypericum perforatum -- Analysis , Hypericum perforatum -- Therapeutic use , Hypericum perforatum -- Physiological effect , Flavonoids -- Analysis
- Description: Most complementary medicines contain a multitude of chemical components, some of which are claimed to contribute to the biological activity of such products. Use of complementary medicines for preventative and therapeutic purposes is increasing rapidly worldwide. Unfortunately, although control of these products is essential to ensure quality, safety, and efficacy, the quality control of most herbal preparations is currently poor to non-existent, with little or no safety and efficacy data required to support the marketing and use of these products. The objective of this study was therefore to develop suitable analytical methods to qualitatively and quantitatively analyse the relevant components (rutin, isoquercitrin, hyperoside, quercitrin, quercetin, kaempferol, hypericin, pseudohypericin and hyperforin) in St John's Wort dosage forms for quality control purposes. A gradient HPLC method using a Luna 5·mC₁₈(2) 150 x 2.00mm internal diameter (i.d.) column and UV detection, was developed for the separation of six of the relevant flavonoid compounds in St John's Wort, namely rutin, isoquercitrin, hyperoside, quercitrin, quercetin and kaempferol. The development process involved a systematic investigation of gradient conditions, flow rate, and temperature. This method was subsequently applied to assay selected commercially available St John's Wort products. This system provided the necessary accuracy, precision and reproducibility and was associated with several advantages when compared to using standard bore (4.60 mm i.d.) HPLC columns. The method developed is currently the only known method that separates all six relevant flavonoids in a reasonable run time (less than 20 minutes). It is also one of the few methods that has sufficient separation between rutin, isoquercitrin and hyperoside. A qualitative method for the fingerprinting of flavonoid components was also developed, using capillary electrophoresis (CE). CE is a rapidly growing powerful analytical technique for the separation of charged compounds. Micellar electrokinetic chromatography (MEKC) is a very powerful electrophoretic technique that is capable of selectively resolving both neutral and ionic solutes in a single run. A MEKC method suitable for the separation and determination of various flavonoid constituents used as marker compounds in Hypericum perforatum was developed. Investigations into the effect of pH, ionic strength, applied voltage and capillary dimensions on separation were performed. The optimised method was then applied to qualitatively analyse various St John's Wort products on the market. This method was found to be advantageous in that it was simple, cost-effective, required minimal sample preparation and utilised very small quantities of sample. Due to the vast differences in chemical properties between the various marker and active components in St John's Wort, it was necessary to develop separate analytical methods for the flavonoids and for the other three relevant compounds (hypericin, pseudohypericin and hyperforin). An isocratic HPLC method using a Luna 5·mC₁₈(2) 150 x 2.00mm (i.d.) column and UV detection was developed for the separation of hypericin, pseudohypericin and hyperforin. The development process involved a systematic investigation of buffer molarity, mobile phase composition, pH, flow rate, and temperature. This method was subsequently applied to assay selected commercially available St John's Wort products on the South African market. This system also provided the necessary accuracy, precision and reproducibility, as well as the advantages associated with the use of a narrow bore column as opposed to the use of the more commonly used wider bore columns. This method was validated and used to quantitate these three compounds in various commercial St John's Wort products. By applying this method to liquid chromatography – tandem mass spectrometry (LC-MS-MS), qualitative analyses of the same products was performed to obtain confirmation of the quantitative HPLC results. Mass spectrometry is a powerful detection tool that is more selective and specific than many detection systems used with HPLC. Natural medicines usually constitute a multitude of constituents with much potential interference. In this regard LC-MS-MS is a powerful tool, with its ability to unequivocally identify target analytes regardless of the presence of interferences or complex matrices. ESI-MS-MS was used for the qualitative analysis of the content of the naphthodianthrones and hyperforin in the respective tablet products assayed with HPLC. LC-MS-MS analyses were performed in order to identify the constituents and to verify the specificity of the HPLC method. High inter-product and inter-batch variability was observed for all nine compounds assayed. These quantitative results were confirmed with the respective qualitative analyses. This study confirms the need for strict quality control of herbal medicinal products commercially available to consumers.
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- Date Issued: 2003
Physiological, perceptual and performance responses during cricket activity
- Authors: King, Gregory Allen
- Date: 2003
- Subjects: Cricket , Sports -- Psychological aspects , Sports -- Physiological aspects
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5131 , http://hdl.handle.net/10962/d1005210 , Cricket , Sports -- Psychological aspects , Sports -- Physiological aspects
- Description: The present study sought to determine the influence of environmental conditions and protective clothing on physiological, perceptual and performance responses during batting activity. The investigation examined mean skin temperature, average heart rate, estimated sweat rate, rating of perceived exertion, thermal sensation rating, average sprint time and pre-post choice reaction time. Twenty-five cricketers (18-22 yr, 73.1 ± 9.6 kg, 1768 ± 75 mm, 12.6 ± 3.1% body fat, 1.89 ± 0.16 m2) performed a work-bout consisting of a seven-Over batting period, during which time they faced deliveries from a bowling machine and performed two shuttle runs every third ball to total four sprints per Over. Trials were carried out under High-stress (23.8 ± 2.2 °C) and Low-stress (13.3 ± 1.9 °C) environmental conditions (WBGT). Within each environmental condition subjects performed the test wearing full protective batting gear and no protective gear. Thus, four specific conditions were examined; high full-gear (HFG), high no-gear (HNG), low full-gear (LFG) and low no-gear (LNG). Two-way ANOVAs were calculated to determine whether there were differences between environmental conditions and whether differences existed between the clothing conditions. One-way ANOVAs were utilised to compute differences between the four specific conditions combining clothing and environment. High environmental stress and wearing protective clothing caused batsmen to experience significant physiological strain. The environment was the greatest stressor, with the protective gear exacerbating these effects. However, when padding covered skin areas directly, this was the primary skin temperature stressor, particularly later in the activity. For skin temperature and heart rate, the strain was the most pronounced at the end of the trials. Perceptual responses indicated that the protective gear had no influence on effort sense, thermal sensation or thermal comfort. However, environmental conditions had an effect, and High-stress conditions resulted in significantly higher perceptions of effort, elevated sensations of heat and greater thermal discomfort. Effort was perceived to be greatest towards the end of the trial. There were mixed findings for performance factors. In general sprint performance was not hindered by environmental stress, but protective clothing caused a reduction in several sprint times. Choice reaction times were for the most part unaffected by either environment or clothing and few differences were observed between pre and post times. It is contended that intense short duration batting activity, likely encountered during one-day participation, imposes a stress on batsmen. The stress is greater when conditions are warmer and protective padding is worn, although it is not sufficient to impede choice reaction time. However, protective gear did have a deleterious effect on sprint performance.
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- Date Issued: 2003
Politics of asylum : sovereign considerations in the multilateral and humanitarian practices of refugee protection in post-apartheid South Africa
- Authors: Oduba, Victor
- Date: 2003
- Subjects: Refugees -- Africa , Refugees -- Government policy -- South Africa , Refugees -- Legal status, laws, etc. -- South Africa , Asylum, Right of -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2870 , http://hdl.handle.net/10962/d1007725 , Refugees -- Africa , Refugees -- Government policy -- South Africa , Refugees -- Legal status, laws, etc. -- South Africa , Asylum, Right of -- South Africa
- Description: Most scholars claim that international human rights norms embodied in formal international declarations and treaties have an important impact on domestic political interests and governmental practices. This reasoning about the impact of global human rights is often applied to the post-apartheid South African immigration and refugee policies. While I acknowledge that the ratification of United Nations Conventions on refugees has altered the traditional sovereignty considerations of South Africa towards asylum seekers, I take issue with the claims that South African refugee and asylum policies are primarily motivated and based on humanitarian considerations. Instead, I argue that these policies are based on sovereign considerations and strategic foreign policy interests. As a result this sovereign interests of South Africa to study has sought to demonstrate that largely explain decisions on the part accept or reject refugees. Although norms diffusion, international advocacy networks, and prestige factors have made a big impact, in practice the refugee policy has continued to reflect South Africa's strategic interests and domestic considerations at all levels. However, I have not argued that South Africa should overlook its national and foreign interests and abide by international human rights norms regardless of the cost of doing so. I have only sought to demonstrate that refugee protection is more when powerful national interests find it conducive to manage the destabilizing refugee flows.
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- Date Issued: 2003
Predictive modelling of species' potential geographical distributions
- Authors: Robertson, Mark Peter
- Date: 2003
- Subjects: Alien plants -- South Africa -- Geographical distribution Species -- Geographical distribution -- Mathematical models Cicadas -- South Africa -- Geographical distribution Scaevola plumieri -- South Africa -- Geographical distribution
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:5816 , http://hdl.handle.net/10962/d1007189
- Description: Models that are used for predicting species' potential distributions are important tools that have found applications in a number of areas of applied ecology. The majority of these models can be classified as correlative, as they rely on strong, often indirect, links between species distribution records and environmental predictor variables to make predictions. Correlative models are an alternative to more complex mechanistic models that attempt to simulate the mechanisms considered to underlie the observed correlations with environmental attributes. This study explores the influence of the type and quality of the data used to calibrate correlative models. In terms of data type, the most popular techniques in use are group discrimination techniques, those that use both presence and absence locality data to make predictions. However, for many organisms absence data are either not available or are considered to be unreliable. As the available range of profile techniques (those using presence only data) appeared to be limited, new profile techniques were investigated and evaluated. A new profile modelling technique based on fuzzy classification (the Fuzzy Envelope Model) was developed and implemented. A second profile technique based on Principal Components Analysis was implemented and evaluated. Based on quantitative model evaluation tests, both of these techniques performed well and show considerable promise. In terms of data quality, the effects on model performance of false absence records, the number of locality records (sample size) and the proportion of localities representing species presence (prevalence) in samples were investigated for logistic regression distribution models. Sample size and prevalence both had a significant effect on model performance. False absence records had a significant influence on model performance, which was affected by sample size. A quantitative comparison of the performance of selected profile models and group discrimination modelling techniques suggests that different techniques may be more successful for predicting distributions for particular species or types of organism than others. The results also suggest that several different model design! sample size combinations are capable of making predictions that will on average not differ significantly in performance for a particular species. A further quantitative comparison among modelling techniques suggests that correlative techniques can perform as well as simple mechanistic techniques for predicting potential distributions.
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- Date Issued: 2003
Progress towards the development and implementation of an unambiguous copper wire fingerprinting system
- Authors: Poole, Martin
- Date: 2003
- Subjects: Electroplating , Copper , Telecommunication , Theft -- Prevention
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5484 , http://hdl.handle.net/10962/d1005270 , Electroplating , Copper , Telecommunication , Theft -- Prevention
- Description: The Telecommunications industry in Southern Africa is faced with the problem of theft of the signal carrying copper wire, both from the ground and from telephone poles. In many cases, if the offenders are caught, the prosecuting party has no way of proving that the wire is the property of any one Telecommunication company, as any inked markings on the insulating sheaths have been burned off along with the insulation and protective coatings themselves. Through this work we * describe the problem, * specify the necessary and preferred technical properties of a viable solution, * report the preliminary investigations into the devising of an unambiguous "fingerprinting" of the 0.5 mm wires, including some of those solutions that, upon investigation, appear non-viable, * describe the development and implementation of an electrochemical marker with detection mechanism which has shown in proof-of-principle to work, * outline the road-map of necessary future work.
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- Date Issued: 2003
Psychoanalysis and realism
- Authors: Rae, Andrew Kenneth McKenzie
- Date: 2003
- Subjects: Psychoanalysis Realism Human beings -- Psychology International relations -- Psychological aspects
- Language: English
- Type: Thesis , Masters , MSocSc
- Identifier: vital:2825 , http://hdl.handle.net/10962/d1003035
- Description: International politics has always been characterised by conflict. This has been true regardless of the political systems in place or of any specific time in the history of humanity. Inter-state conflict exists today despite the fact that the vast majority of the states of the world are members of the United Nations and signatories to various treaties aimed at removing conflict as a means of state action. The realist school of thought argues that the international system is characterised by continual state conflict, caused by competition over scarce resources. The propensity towards conflict is argued to be an essential characteristic of human nature and, as such, human nature is considered to be aggressive and conflictual. Thus, for the realist, inter-state competition, coupled with aggressive human nature, constitutes the primary cause of interstate conflict. This thesis aims to examine two criticisms of the realist position in depth. The first concerns the attribution of human nature to states. This logical progression is problematic because it creates a type of „state-nature‟ that cannot be defended without providing a logical link between the individual, the group and the state. It is therefore an aim of this thesis to provide this link, using methodological individualism, in order to provide a basis for the attribution of human nature to states. The second aim of this thesis is to examine the notion of human nature that is offered by the realists. It is not enough to claim that human nature is aggressive and conflictual merely because conflict has characterised international relations throughout history. Rather, one should examine the individual‟s psychological development, in order to gain an understanding of aggressive instincts apparent in human nature. The thesis therefore examines psychoanalysis in order to attempt an understanding both of human nature, and of the conditions under which human nature may manifest itself in an aggressive, conflictual manner. The intention of this thesis, then, is to provide a defence of political realism, highlighting the shortcomings of the two criticisms outlined above.
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- Date Issued: 2003
Putting participatory communication into practice through community radio: a case study of how policies on programming and production are formulated and implemented at Radio Graaff-Reinet
- Authors: Kanyegirire, Andrew Steve Tumuhirwe
- Date: 2003
- Subjects: Radio broadcasting -- South Africa -- Graaff-Reinet , Radio in community development , Radio stations -- South Africa -- Graaff-Reinet -- Management
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3442 , http://hdl.handle.net/10962/d1002896 , Radio broadcasting -- South Africa -- Graaff-Reinet , Radio in community development , Radio stations -- South Africa -- Graaff-Reinet -- Management
- Description: In the South African (SA) model of community radio, listeners are expected to be in charge of the management and programming operations of stations. This study tests the SA model against the actual conditions at an existing station. For this purpose, the study focuses on Radio Graaff-Reinet, a community radio station in the Eastern Cape. Emphasis is on examining the extent to which members of the station’s target community are involved in its operations. The study first assesses the nature of this involvement, keeping in mind the principles of, ‘community ownership’ and ‘participatory programming’ on which the SA model of community radio is based. It is argued that the station does provide a valuable ‘public sphere’ for its listeners. The potential of this sphere remains limited, however, due to the impact of ongoing power struggles around the ownership of the station. The lack of proper systems for managing these struggles has contributed to the fact that the station continues to be in a constant state of flux, with a high turnover of staff and regular changes in its policies and strategies. The study argues that, until such systems are put in place, the principles of community ownership will not be fully realizable. Areas in which the struggle over ownership plays itself out can be identified in the relationship between the station’s Board of Directors and its managing staff, between one particular station manager and her staff and between the station and its target community. These struggles often take place in context of a debate about the financial sustainability of the station versus its developmental aims. It is argued that this opposition needs to be questioned since, until the station is financially stable, it will remain vulnerable to interference by powerful individuals and groups in its attempts to establish such developmental aims. The study then goes on to identify key weaknesses in the station’s approach to community ownership and participation. In particular, it is pointed out that various stakeholders in the station have contradictory understandings of what is meant by ‘community’, using the term to include or exclude sections of the Graaff-Reinet society in very different ways. There are also very different understandings at play about the concept of community radio itself. These contradictions have an impact on the station’s ability to implement participatory programming. This situation is exacerbated by the fact that the station does not have a consistent forum in which shared decision-making can take place. Consequently, the station also remains unable to draw effectively on its own volunteer staff and on its community as resources for programming content. Finally, the study explores the broader significance of the weaknesses that exist in the case of Graaff-Reinet, arguing that these are problems that repeat themselves throughout the South African community radio sector. Possible strategies for addressing these problems are suggested, including approaches to monitoring and research, training, organizational development and advocacy.
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- Date Issued: 2003
Pyrroloiminoquinone metabolites from South African Latrunculid sponges
- Authors: Antunes, Edith Martins
- Date: 2003
- Subjects: Sponges -- South Africa PQQ (Biochemistry) Marine metabolites -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:4340 , http://hdl.handle.net/10962/d1005001
- Description: An in depth chemical investigation of the major and minor pyrroloiminoquinone metabolites produced by four species of endemic South African Latrunculid sponges, collected from Algoa Bay and the Tsitsikamma Marine Reserve off the south eastern coast of South Africa, yielded eleven new and twelve known pyrroloiminoquinone metabolites. The structures of the new metabolites were determined using standard spectroscopic techniques. Tsitsikamma pedunculata was shown to contain 7,8-dehydro-3-dihydro-discorhabdin C (2.1), 14-bromo-7,8-dehydro-3-dihydro-discorhabdin C (2.2), discorhabdin S (2.3), 14-bromo-1-hydroxy-discorhabdin S (2.4), 1-bromo-2-hydroxy-4-debromo-discorhabdin S (2.5), and 2,4-debromo-3-dihydro-discorhabdin C (2.6), together with the known compounds 14-bromo-discorhabdin C (1.51), 14-bromo-3-dihydro-discorhabdin C (1.52) and 3-dihydro-discorhabdin C. The metabolites from T. pedunculata were characterised by the presence of a reduced C-3 carbonyl and bromination at C-14. Compounds isolated from a second Latrunculid sponge, Latrunculia lorii, ranged from a substituted bicyclic pyrrolecarboxylic acid, makaluvic acid A (1.47), to the simple tricyclic known pyrroloiminoquinones makaluvamine C (1.33) and damirone B (1.20) and the more complex discorhabdin D type metabolites, discorhabdin M (3.2), 1-amino discorhabdin D (3.3), 1-methoxy discorhabdin D (3.4) and 1-alanyl discorhabdin D (3.5). Discorhabdin G* (3.1) was also isolated and characterised. This is the first reported occurrence of the known compounds 1.20, 1.33 and 1.47 in a Latrunculia sponge. Discorhabdin and bis-pyrroloiminoquinone type compounds predominated in Tsitsikamma favus. Three known, tsitsikammamines A (1.71) and B (1.72), 1.52, and five new pyrroloiminoquinones, tsitsikammamine N-oxime (4.1), tsitsikammamine B N-oxime (4.2), 2.1, 2.4 and 2.6, were isolated from this sponge. A fourth Latrunculid sponge (Strongylodesma sp.) yielded three known compounds, discorhabdins A (1.57), D (1.61) and 1.53, and one new pyrroloiminoquinone 3.3. The dual role of these metabolites as cytotoxic agents and pigments resulted in an attempt to relate the photochemical properties of these metabolites to their cytotoxicity. The pyrroloiminoquinone metabolites studied exhibited moderate singlet oxygen quantum yields, while three compounds (1.57, 4.1 and 4.2) were shown to be capable of producing radicals at a wavelength of 532 nm. The possibility of a correlation between the electrochemical properties and anti-cancer (HCT-116) activity of selected pyrroloiminoquinones was explored. A study of the oesophageal and ovarian cytotoxicities of two pyrroloiminoquinones (1.57 and 1.72), together with an investigation into the intercalation and topoisomerase I inhibitory activity of the bis-pyrroloiminoquinones (1.71, 1.72, 4.1 and 4.2), are presented.
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- Date Issued: 2003
Regionalism and conflict resolution in the Horn of Africa : the role of inter-governmental authority on development in the Sudanese civil war
- Authors: Onyango, Moses
- Date: 2003
- Subjects: Africa, Northeast -- Politics and government -- 1900-1974 , Africa, Northeast -- Politics and government -- 1974- , Africa, Northeast -- Foreign relations -- 1974- , Federal government -- Africa, Northeast , Sudan -- History -- Civil War, 1955-1972 , Mediation, International , Culture conflict Sudan
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2869 , http://hdl.handle.net/10962/d1007715 , Africa, Northeast -- Politics and government -- 1900-1974 , Africa, Northeast -- Politics and government -- 1974- , Africa, Northeast -- Foreign relations -- 1974- , Federal government -- Africa, Northeast , Sudan -- History -- Civil War, 1955-1972 , Mediation, International , Culture conflict Sudan
- Description: This thesis expounds the theoretical underpinnings of problem-solving approach to conflict resolution. It also criticizes the traditional state-centric approach to conflict resolution being followed by the Inter Governmental Authority on Development (IGAD) in the Sudanese civil war. IGAD was initially known as Inter Governmental Authority on Drought and Desertification (IGADD), but was renamed IGAD in 1996. Its objectives were reformulated to give priority to conflict prevention, resolution, and management, and humanitarian affairs. It is stipulated in the thesis that IGAD faces problems that need attention if the Sudanese civil war is to be resolved. A key problem is that while IGAD's objectives were reformulated to give priority to conflict resolution, IGAD's management structure has remained the same. The management structure is state-centric and lacks neutrality, which is a very important ingredient in deep-rooted social conflict resolution. The management structure, which was initially based on combating drought and desertification, was not restructured to conform to the realities of a problem solving approach to conflict resolution. The committee that was formed to look into the Sudanese conflict is composed of states in dispute with Sudan. The other structural problem cited in the thesis is that the IGAD peace process is cumbersome and does not include all aggrieved parties. The meetings involve heads of state, ministers, ambassadors and other government representatives. The peace process is not inclusive of other important players such as other rebel movements. This thesis concludes that: 1. there is a need for peace keeping forces from neutral African Union (AU) member states; 2. conflict resolution specialists are deployed in the region whose main task would be to assist the belligerent groups to reach a common understanding of their problems; 3. the United Nations (UN) acts proactively to create international awareness to the Sudanese problem.
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- Date Issued: 2003
Review and development of environmental interpretation resources to foster environmental learning in two Kenyan schools
- Authors: Atiti, Abel Barasa
- Date: 2003
- Subjects: Environmental education -- Kenya Environmental education -- Kenya -- Case studies
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1743 , http://hdl.handle.net/10962/d1003627
- Description: This participatory action research study involved a group of teachers in transforming school grounds into interpretation resources. Approached from a critical perspective, it challenged the conventional top-down approaches to interpretation resources and materials development. Through a teacher-centred approach, a school-based ‘botanic garden’ and ‘arboretum’ were developed at Samaj and Kenya High respectively. Teachers were further actively engaged in developing a variety of interpretive materials that might engage learners in socially critical environmental education processes at the transformed sites. A process in which educators from five non-formal education organisations shared their skills and knowledge on environmental interpretation with teachers preceded the development of interpretation resources and materials. Drawing on Latour (1999), I have applied the notion of mobilising interpretive capital when describing this process. Interpretive capital within the non-formal education sector was mobilised and made available through social interactions between teachers and non-formal educators. This occurred during workshops, organisational visits and critical reviews of a sample of interpretive materials. I provide insights into how the interpretive capital was mobilised and later drawn on by teachers during the development processes in their schools. This study argues that mobilising interpretive capital with teachers through partnerships can enhance the transformation of school grounds to foster environmental learning. It shows how attempts to find solutions with teachers were made in response to pedagogical and curriculum tensions that arise around the implementation of environmental education processes in their schools. To provide orientation in environmental education processes in schools, analyses of socially critical environmental education processes and a review of theoretical perspectives on interpretation as an environmental education process are presented. I have viewed interpretation and environmental education as reciprocally necessary aspects for enabling the development of critical environmental literacy and action competence. To explain this view, the notion of environmental interpretation and education processes has been applied and presented in this study. Finally, practical outcomes of the study on transformation of school grounds, improved education practice, enhanced professional competencies amongst teachers, new interpretive materials in schools and the establishment of partnerships are examined.
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- Date Issued: 2003
Rights to reality - the right to social security, with particular emphasis on the legal resources centre's welfare project in the Eastern Cape
- Authors: Delany, Mairéad Christine
- Date: 2003
- Language: English
- Type: Thesis , Masters , LLM
- Identifier: vital:21027 , http://hdl.handle.net/10962/6052
- Description: This research addresses the question of whether the courts have been used effectively to enforce the right to social security in the Eastern Cape. The nature of the right to social security is discussed and placed in the context of constitutional developments in South Africa and South Africa's obligations in terms of international law. The enforcement of socio-economic rights and legislation regarding social assistance is also discussed in detail, along with the problems associated with the social security system such as the gaps in the system, the impact of HIV / AIDS and the problems created by the amalgamation of various administrations. The history of the Legal Resources Centre, a non-governmental organisation which has been involved in public interest law for twenty four years, is detailed. The Grahamstown office's litigation campaign against the Eastern Cape Department of Welfare is then discussed and six landmark cases are analysed in detail. A discussion of the jurisprudential significance and impact of each case on the development of South African administrative and constitutional law follows. A series of stories reported in the press illustrate the human aspect of the campaign and balance the legal argument. These stories may suggest that the Constitution's commitment to social justice and the government's commitment to the principles of Batho Pete are merely noble ideals for many people in the province, but it is argued that the LRC's campaign has made a vast contribution towards making these ideals a reality on the ground. The expert opinions of various groups interviewed during the course of this research regarding the impact of the LRC's litigation campaign are discussed, and the conclusion is drawn that it has indeed had a positive effect. They include paralegals at Advice Offices around the province, legal practitioners from the LRC, a private legal practitioner, several representatives of the Black Sash, a former MEC for Health and Welfare in the Eastern Cape Provincial Government, an official from the Department, and a leader of the Anglican Church in the province. In conclusion it is submitted that, but for the LRC's litigation campaign, the situation in the Eastern Cape would not have improved to the extent it has and may even have deteriorated further. Furthermore, it is submitted that as a result of the litigation campaign, the right to social security, and particularly the right to social assistance, is more accessible and more of a reality on the ground.
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- Date Issued: 2003