Includes bibliographical references. / Evaluating the performance of organisations is essential to good planning and control. Part of this process is monitoring the performance of organisations against their goals. The comparative efficiency of organizations using common inputs and outputs makes it possible for organizations to improve their performance so that can operate as the most efficient organizations. Resources and outputs can be very diversified in nature and it is complex to assess organizations using such resources and outputs. Data Envelopment Analysis models are designed to facilitate this of assessment and aim to evaluate the relative efficiency of organisations. Chapter 2 is dedicated to the basic Data Envelopment Analysis. We present the following: * A review of the Data Envelopment Analysis models; * The properties and particularities of each model. In chapter 3, we present our literature survey on restrictions. Data Envelopment Analysis is a value-free frontier which has the of yielding more objective efficiency measures. However, the complete freedom in the determination of weights for the factors and products) relevant to the assessment of organisations has led to some problems such as: zero-weights and lack of discrimination between efficient organizations. Weight restriction methods were introduced in order to tackle these problems. The first part of chapter 3 in detail the motivations for weight restrictions while the second part presents the actual weight restriction rnethods.

Includes bibliographical references (leaves 61-67). / Various sources of evidence suggest that dream frequency, intensity and vividness are increased with the use of selective serotonin reuptake inhibitors (SSRJ's) commonly prescribed for depression and anxiety. In this study the effects ofSSRI use on dream frequency, intensity and vividness in psychiatric patients was examined through a comparision of the dream characteristics of an SSRI- medicated patient group vs. an unmedicated patient control group. Each group comprised 20 patients recruited through state psychiatric outpatient facilities affiliated with two research universities. Age and gender were evenly spread across the two groups. Psychiatric disorders represented were generalised an.xiety disorder, panic disorder, obsessive-compulsive disorder and social phobia. Patients completed a questionnaire consisting of a most recent dream report and self-report likert-scaled questions regarding dream frequency, intensity, vividness and memorability. Two independent raters rated the dream reports for intensity on a likert scale. Self-reported visual vividness was significantly higher (p=0.027, effect size .86) among SSRI users compared with controls, whereas selJreported dream frequency and emotional intensity as well as independent raters assessment of dream intensity were not significantly different across the two groups. Findings of increased dream vividness without increases in dream frequency complement the results of an earlier study. Since serotonin is suppressed during REM sleep, these findings cast further doubt upon the notion of an isomorphic link between REM sleep and dreaming and argue for the searchfor a more sophisticated model of neurotransmitter modulation of sleep-cognition.

Includes bibliographical references (leaves 83-89). / This study extends Gibson and Gouws ' (2003) work on threat and intolerance as well as Kuklinski, Riggle, Ottati, Schwarz and Wyer's (1991) work on the influence of emotion on people's tolerance judgements. Method: Participants were randomly assigned to two experimental groups.

Includes bibliographical references (leaves [122]-132). / This qualitative study investigated the effect of a mother's physical disability on the mother-adolescent relationship, parenting and the adolescent's engagement in risky behaviour. Interviews were conducted with five mothers with visible physical disabilities and with their adolescent children. The adolescents comprised two boys and three girls between the ages of 12 and 15 years. All five mother-adolescent dyads were black, with low maternal educational levels, from low socio-economic backgrounds, and lived in neighbourhoods characterised by unemployment, gangsterism, substance abuse, violence and crime. The multiple case study design was used to compare and contrast evidence from the individual cases. Two separate semistructured interviews, covering the same topics, were conducted with both the mother and the adolescent in order to triangulate the data. The interviews focused on perceptions of (a) the impact of the mother's disability for mother-adolescent relations; (b) disability-related stigma and the adolescent's awareness of the mother's difference on the mother-adolescent relationship; (c) the ways in which the mother's disability and other contextual factors affect parenting and the adolescent's engagement in risky behaviour. The results illuminated a range of barriers andfacilitators to parenting with a physical disability but the variability notwithstanding, the majority of the families reported positive relationships and experiences given the cumulative stressors that they face.

Includes bibliographical references (leaves 125-136). / The aim of this study was to investigate the current crystal methamphetamine problem and its trends of abuse as manifested in the local context of Cape Town, South Africa. Twelve individuals (four ex-users, five users in recovery and three current users) who were dependent on crystal methamphetamine took part in the study. They ranged between the age of seventeen and twenty eight years. Semi-structured interviews were conducted in order to gather participants' stories about their subjective understanding of their dependence on crystal methamphetamine. Onset of use was often driven by curiosity and/or peer pressure, as well as to avoid states of psychological discomfort. Crystal methamphetamine use was usually maintained due to the enjoyment of its rewarding effects. Smoking the substance became especially important with more regular use as it served as a powerful, albeit temporary, stress eliminator. Crystal methamphetamine ubiquity appeared to be highly influential in the onset as well as maintenance of the substance's consumption. A range of debilitating physiological and psychological symptoms comprised the state of dependence. The presence of psychotic symptoms was rife within the sample and was often indicative of severe and prolonged crystal methamphetamine use. An inability to function within the external 'drug-free reality' was characterised by participants not being able to fulfill responsibilities and thus was also suggestive of maladaptive patterns of use. Polydrug use was generally common among participants. Some female participants' narratives also pointed towards the association of crystal methamphetamine use and sexual risk-taking behaviours. Identifying an external motivating factor was important in encouraging cessation of use but internal motivation often appeared to be just as significant in attaining as well as sustaining abstinence. Sleeping was the most common strategy used in dealing with the state of severe withdrawal which followed post use. In general, most participants did not perceive treatment as being the most useful means of achieving sobriety. Identifying goals and a perceived sense of purpose appeared important in motivating the individual along the path towards recovery as well as in the maintenance of abstinence.

Includes abstract. / Includes bibliographical references (p. 116-140). / Lynch syndrome (LS), the most common form of inherited colorectal cancer (CRC), carries with it a lifetime risk of approximately 80% of developing CRC. This study identified unexpected findings with regard to the relationships between neuropsychological functioning, knowledge and non-adherence within the context of LS, and highlights ways in which this might be investigated in the future.

Sumaary in English. / Includes bibliographical references. / Background: Due to the geographic distance between abattoirs and commercial valve plants delays between harvest and fixation usually range from 48 to 72 hours. In order to assess the pre-fixation tissue damage arising from the hypoxic period and the resulting calcific degeneration after implantation, we used an ultrastructural damage score and transmission electron microscopy. Materials and Methods: In a step by step manner, three major issues were clarified: 1) The degree of pre-fixation tissue damage was determined in the four most widely used commercially produced tissue heart valves. Since stentless bioprostheses represent the latest promising trend in the development of biological heart valves, stentless models of the following makes were compared: Baxter, Medtronic, St. Jude and Biocor. Due to the fact that the aortic wall component of these valves proved most resistant to all anticalcification treatments, aortic wall tissue stood in the centre of our analyses. 2) Subsequently, three main determinants of the fixation process namely: delay, temperature and fixative-concentration were varied with the goal of significantly improving the ultrastructural preservation of the bioprosthetic tissue. 3) Eventually, the influence of improved ultrastructural preservation on calcific degeneration was evaluated under in vivo conditions in the non-human primate and the rat model. Results: The comparison of the four most commonly used stentless bioprosthetic heart valves revealed a disturbing degree of tissue damage in all valves. Using a damage score from 1 to 21 (21 being the worst), aortic wall tissue of commercial valves ranged from 10 to 18 and that of leaflet tissue from 12 to 20. When fixation conditions were permutated, tissue damage could almost be abolished by immediate fixation (within 30 minutes of slaughter), low-temperature fixation(4°C) and high glutaraldehyde concentrations (> 1 %). Our in vivo experiments confirmed that commercially used fixation (delayed fixation, room-temperature and I ow concentrations of glutaraldehyde) with its concomitant high degree of tissue damage results in high levels of calcification. Apart from a distinctly improved calcification potential in ultrastructurally well preserved tissue, there was also an inverse correlation between tissue calcification and the concentration of glutaraldehyde used for fixation. Conclusion: We could demonstrate that commercially produced bioprosthetic heart valves uniformly show badly damaged tissue and that tissue damage contributes to the calcific degeneration of these valves. We were also able to determine ideal fixation conditions which in turn significantly reduced tissue calcification.

Includes bibliographical references. / It has been shown that sardine and anchovy populations in the southern Benguela have alternated dominance during the past 50 years, and a frame based model that explores the usefulness of frames within a marine ecosystem by modelling sardine/anchovy dominance shifts in the southern Benguela has been developed in a previous study. The existing model contains a sardine population sub-model without age structure and the inclusion of age-structure allows age-related dynamics to be incorporated in the model design. In this mini-dissertation, an age-structured sardine population is implemented in the frame based model by using the sardine assessment model from the joint sardine/anchovy Operational Management Procedure, OMP-02. Methods for incorporating biological processes - such as the hypothesised school trap phenomena - that were present in the existing frame based model into the OMP-02 equations are developed, critically analysed and tested.

Includes bibliographical references. / This study examined treatment response and participant characteristics amongst substance misusing clients of a Cape Town low-cost out-patient treatment programme.A theory-based approach to the evaluation was used and substance use outcomes of participants were measured over the three time periods of admission, 6- weeks postadmission (immediately after the intervention) and 10-weeks post-admission as were elements of the Centre's causal chain mechanism: Relationships between the domains of motivation (comprising the three sub-scales of Recognition, Taking Steps and Ambivalence), drug-taking confidence (self-efficacy), Alcoholics/Narcotics Anonymous affiliation and previous clean time against levels of substance use and severity of dependence at each time point were measured. Substance use and levels of severity of dependence should decline over time. As Self-Efficacy, Taking Steps and NA/AA Affiliation scores increase, so substance use levels and levels of severity of dependence should decrease. Higher scores of Recognition and Ambivalence should be associated with higher levels of substance use and severity of dependence. Forty seven percent of participants reported abstinence of all substances at 10-week follow-up and a further 13% abstained from all substances with the exception of alcohol which they had used only once or twice. Reductions in use of individual substances were high: 95% of participants who, on admission, reported use of methaquolone (mandrax), 89% of heroin users, 84% of cocaine users and 73% of methamphetamine users reported abstinence of those drugs at 10-week follow-up. Self-Efficacy and Taking Steps scores significantly increased over time and were also significantly associated with reduction in substance use and severity of dependence. Higher Recognition scores were significantly associated with higher levels of substance use at admission and 10-week follow-up. There was an inverse association between amount of exposure to the treatment programme and levels of substance abuse and severity of dependence. NA/AA affiliation was low at all time points and did not appear to be associated with reductions in substance use. As substance use and substance dependence significantly decreased and as measurable elements in the chain of causal mechanisms changed over time consistent with programme causal theory, and as the change in those elements impacted on levels of substance use in a significant way, it can be tentatively suggested that there was a treatment programme effect.

Bibliography: leaves 126-139. / Given South Africa's ethnic complexities, comparatively little has been written about the group known as white English-speaking South Africans, or WESSAs. This is partly because of the lack of collective sentiment shared by people categorised as WESSAs, partly because the group boundaries are not clear-cut, and partly because on the surface there appears to be little that can be said about them. Besides a proclivity for business, a continued attachment to Europe and an apparent inability to organise politically, the acollectivity of the group has been the focus of the literature on the subject, and its cause has been a matter of some bewilderment on the part of authors. This work examines WESSA identity from a new perspective, one influenced by the proliferation of writings on the topic of "whiteness" in Europe and America in recent years. These writings concentrate on how whiteness as a set of discourses positions being white as neutral or "raceless", in contrast to other race groups who are constructed as "ethnic".