The P300 serves as a valuable tool in examining higher auditory functions such as auditory attention and discrimination. Exploration of the P300 could be of value in a multi-lingual South Africa where auditory processing evaluations still rely heavily on inappropriate linguistically dependent tests. The P300 could potentially provide an objective, non-linguistically dependent evaluation of auditory processing. The present study aimed to investigate the influences of gender on the Auditory P300 Event Related Potential (AERP) and to contribute to establishing a clinic-specific normative database. One hundred subjects (n=100) (50% male) with normal hearing and no history of psychiatric illness were evaluated using the “odd-ball” paradigm. The averages and ranges of the findings on latencies and amplitudes were reported. The average latency values for the P300 were calculated at 314.7ms with a standard deviation of 37.2 ms. The average amplitude values were calculated at 7.1 µV with a standard deviation of 6.1 µV. No significant gender effect was found. In conclusion further research is recommended to explore the clinical utility of the P300 in different age and gender groups, using different protocols. / Dissertation (M (Communication Pathology))--University of Pretoria, 2007. / Speech-Language Pathology and Audiology / unrestricted

The purpose of the study was to evaluate the EAP’s internal marketing strategy in the National Prosecuting Authority. The study was conducted at the Head Office in Pretoria. The sample comprised of one hundred and three (103) employees of the NPA, representative of all business units in the organisation. The sample was drawn from the population using stratified random sampling method. The required number of respondents was further selected proportionally from each stratum using random sampling. The research approach followed in the study was a combination of qualitative and quantitative approach, dominant-less-dominant survey design. The research approach was predominantly quantitative, and a small qualitative component was incorporated, which aimed to explore one aspect of the study where respondents were required to give recommendations for improvement of the EAP internal marketing strategy within the organisation. A theoretical background on EAP internal marketing was provided through a literature study. In the literature study, the goals, objectives and elements of EAP marketing were discussed. The aspects of EAP that are critical for EAP marketing were explored and discussed. The literature study also included a discussion of various EAP marketing strategies. A practical review of marketing strategies employed by four companies was done in order to compare with the strategies implemented in the organisation where the study was conducted. The section concluded with the discussion of challenges of developing an internal marketing strategy. The empirical part of the study focused on the evaluation of the Employee Assistance Programme internal marketing strategy in the National Prosecuting Authority. The aim of the study was to determine whether the internal marketing strategy implemented was effective. A questionnaire was used as a research tool and distributed to the respondents. The findings of the study were based on ninety-nine (99) questionnaires that were returned by respondents. The findings were presented and analysed using tables and graphs, and also interpreted in words. The study revealed that generally, respondents were aware of the existence of the EAP. However, there is a great need to improve on the EAP internal marketing strategy in order to increase awareness of the different components and services of the programme. The hypothesis of the study was that marketing activities improve knowledge of EAP services amongst employees. The results of the study supported the hypothesis since respondents that were exposed to various EAP marketing material and methods of communication were aware of the different aspects of the programme than respondents who were not exposed Based on the findings of the study, conclusions and recommendations were made regarding the improvement of the EAP marketing strategy in the NPA. / Dissertation (M Soc.Sci (EAP))--University of Pretoria, 2007. / Social Work and Criminology / unrestricted

Increasing prominence is given to the role of optimization in engineering. The global optimization problem is in particular frequently studied, since this difficult optimization problem is in general intractable. As a result, many a solution technique have been proposed for the global optimization problem, e.g. random searches, evolutionary computation algorithms, taboo searches, fractional programming, etc. This study is concerned with the recently proposed zero-order evolutionary computation algorithm known as the particle swarm optimization algorithm (PSOA). The following issues are addressed: 1. It is remarked that implementation subtleties due to ambiguous notation have resulted in two distinctly different implementations of the PSOA. While the behavior of the respective implementations is markedly different, they only differ in the formulation of the velocity updating rule. In this thesis, these two implementations are denoted by PSOAF1 and PSOAF2 respectively. 2. It is shown that PSOAF1 is observer independent, but the particle search trajectories collapse to line searches in n-dimensional space. In turn, for PSOAF2 it is shown that the particle trajectories are space filling in n-dimensional space, but this implementation suffers from observer dependence. It is also shown that some popular heuristics are possibly of less importance than originally thought; their greatest contribution is to prevent the collapse of particle trajectories to line searches. 3. A novel PSOA formulation, denoted PSOAF1* is then introduced, in which the particle trajectories do not collapse to line searches, while observer independence is preserved. However, the observer independence is only satisfied in a stochastic sense, i.e. the mean objective function value over a large number of runs is independent of the reference frame. Objectivity and effectiveness of the three different formulations are quantified using a popular unimodal and multimodal test set, of which some of the multimodal functions are decomposable. However, the objective functions are evaluated in both the unrotated, decomposable reference frame, and an arbitrary rotated reference frame. 4. Finally, a practical engineering optimization problem is studied. The PSOA is used to find the optimal shape of a cantilever beam. The objective is to find the minimum vertical displacement at the edge point of the cantilever beam. In order to calculate the objective function the finite element method is used. The meshes needed for the linear elastic finite element analysis are generated using an unstructured remeshing strategy. The remeshing strategy is based on a truss structure analogy. / Dissertation (MEng (Mechanical Enigneering))--University of Pretoria, 2007. / Mechanical and Aeronautical Engineering / unrestricted

A total of 94 Salmonella isolates were collected from three catchments areas in Eritrea. These isolates were recovered from clinical and environmental sources. Biochemical tests using gelatin hydrolysis and tartrate utilization test were employed to differentiate between Salmonellasubspecies. All Salmonellaisolates were identified as Salmonellasubspecies I and were then subjected to molecular characterization. Polymerase chain reaction (PCR) and amplified fragment length polymorphism (AFLP) were employed to identify and establish possible relationships between the clinical isolates and environmental sources. Two sets of oligonucleotide primers specific for genes from S. Typhimurium and S. Enteritidis were used for the PCR reaction. Of the 94 Salmonellaisolates characterized only 6 were S. Typhimurium strains. To type the Salmonellaisolates AFLP was used. Clustering the AFLP patterns using the un-weighed pair-group method using arithmetic means (UPGMA) revealed 15 clusters. Of the 94 Salmonellaisolates collected, 48 (51%) strains were serologically identified. These serotypes include, 21 SalmonellaEmek (43.7%), 19 SalmonellaHeidelberg (39.5%), 7 of the 13, 22, 23; z undetermined serotype (14.5%), and 2 SalmonellaTyphimurium strains (4.1%). The AFLP data in the present study indicated a possible relationship between the clinical isolates and those obtained from environmental sources. / Dissertation (MSc (Microbiology))--University of Pretoria, 2007. / Microbiology and Plant Pathology / unrestricted

This study was done in the communal area surrounding Makoko village and in the adjacent conservation area within the Kruger National Park, Mpumalanga province, South Africa. The structure of the woody vegetation within the two areas were compared in terms of species diversity, density, size structure distribution and biomass to determine the impact of fuel wood harvesting within the communal area upon the woody vegetation. There was no difference in woody plant species richness between the conservation and communal areas, but there was a difference between the uplands and lowlands. The conservation area uplands had the highest woody plant density and woody plant biomass. There were differences between areas in terms of the woody size class structure. The socio-economic status of Makoko village was determined by interviewing 100 households within the village. The use of fuels including wood, paraffin, candles and electricity was determined. Community and Kruger National Park issues such as advantages and disadvantages of living adjacent to the Kruger National Park were also noted. The demand for fuel wood within Makoko village was 338.9 kg per person per year, but the supply of fuel wood in the communal area was only 54.6 kg per person per year, if harvested sustainably. A conservation area of equal size could provide 270.0 kg of fuel wood per person per year on a sustainable basis. Management recommendations were made towards achieving sustainability in the use of the woody plant resources. / Dissertation (MSc (Wildlife Management))--University of Pretoria, 2007. / Centre for Wildlife Management / unrestricted

Understanding abstract concepts and ideas in mathematics if instruction takes place in the first language of the student is challenging as it is. Yet worldwide students often have to master mathematics via a second or even a third language and this is a recognised problem. The majority of students in South Africa – a country with eleven official languages – have to face this difficulty. What is the extent of the linguistic disadvantage (if any) of South African second language students? With the language challenges that South Africa faces today with respect to education as a backdrop, I report on a quantitative investigation into this problem specifically for the case of tertiary mathematics students, focussing on Afrikaans first language learners. The performance of Afrikaans first language students who attend Afrikaans lectures is compared to that of the Afrikaans first language students who attend English lectures. In a further investigation I explore the influence that second language instruction has on students from African cultures. All the students study at the University of Pretoria. The study shows that in the comparison of the average performances of the two Afrikaans first language groups, there is no significant difference in the first year university calculus performances, but at secondary school level the Afrikaans students who attend English lectures at university level achieve better results. When the means are adjusted by removing the influence of school mathematics achievement, the adjusted average performance of the Afrikaans group that attend English lectures differ significantly from that of the Afrikaans group that attend Afrikaans lectures. As a result both of the analyses suggest that, based on mathematics achievement, Afrikaans students who attend English lectures may be at a disadvantage to Afrikaans students attending English lectures do. The study also indicates that the African students' performances do not differ significantly from that of the Afrikaans students who attend English lectures (both of these groups attend second language lectures). In the comparison of the pooled groups of first language learners and second language learners, there does not seem to be any significant difference between the adjusted mean performances of these groups. / Dissertation (MSc (Mathematics Education))--University of Pretoria, 2007. / Mathematics and Applied Mathematics / unrestricted

Breast cancer is one of the most common cancers affecting women. It remains the leading cause of death in American women from 30 – 70 years of age and approximately 10% of the women living in western countries will develop breast cancer during their life time. Estrogens are a family of female hormones involved in the reproductive function of the human body. Estradiol is the most abundant estrogen in premenopausal woman. Initially it was thought that estradiol itself was responsible for tumourigenesis, but it has since been discovered that the catechol metabolites of estradiol and other estrogens cause carcinogenesis. 4-Hydroxyestradiol (4-HE2) is a potent cell proliferating estrogen whereas 2-methoxyestradiol (2-ME2) is a potent inhibitor of cell proliferation through the activation of apoptosis. 2-Hydroxyestradiol (2-HE2) also causes increased cell proliferation but it is not as potent as 4-HE2 and it is <font face="symbol">O</font>-methylated rapidly to 2-ME2. Catechol metabolites of estradiol are also involved in producing reactive oxygen species through redox cycling. The reactive oxygen species cause DNA damage and mutations to occur which can lead to carcinogenesis. A significant ratio to consider as a biomarker for breast cancer risk therefore is the 4-HE2/2-ME2 ratio. In this study, an analytical method was developed to measure the concentration levels of E2, 2-ME2, 2-HE2 and 4-HE2 in cell culture medium. The analytical method made use of gas chromatographymass spectrometry (GCMS) analysis, since the expected physiological concentrations of these metabolites were very low. Various extraction and derivatisation techniques were applied during the development of the method. The final method made use of protein precipitation with concentrated hydrochloric acid, liquid-liquid extraction using diethyl ether and derivatisation with trimethylsilylimidazole (TMSI). During the validation of this method, it was found that the method did not produce accurate measurements and that it could only be used to determine trends. Since the precise in vitro concentration levels of the metabolites were still unknown, it was decided to proceed with experiments using this method, to provide preliminary results with which further course of action could be planned. Equal numbers (1x106 cells/flask) of MCF-7 and MCF-12A cells were provided with 11 ml medium containing E2/2-HE2/4-HE2/2-ME2 (10-6 M) and medium containing E2/2-HE2/4-HE2/2-ME2 (10-8 M). Of each metabolite and each concentration two flasks were prepared. Each flask represented a specific time interval. At the appropriate time 10 ml of the medium was extracted. The time intervals used for each experiment were 0 hours, 8 hours and 24 hours for incubation with E2, 0 hours, 1 hour and 8 hours for incubation with 2-ME2, 0 hours, 10 minutes and 1 hour for incubation with 2-HE2 and 4-HE2. The time intervals used were according to the expected rate of metabolism. Each experiment was repeated three times. Differences in the metabolism of breast tumour cells and normal cells were found and the concentration of the metabolites present in the cell incubation medium had an influence on the metabolism of the cells. The need to investigate the intracellular concentrations of the metabolites has also been accentuated through the results obtained. / Dissertation (MSc (Physiology))--University of Pretoria, 2007. / Physiology / unrestricted

Background: It is likely that lower limb ulceration, lower limb amputation, or their absence in diabetic subjects, indicate varying degrees of long-term diabetes and its complications, and that measures of atherosclerosis and neuropathy would reflect these differences. Objectives: To determine feasibility and, based on our results, make sample size estimates for future study: By comparing peripheral and central vasculature between diabetic subjects with lower extremity ulcers, diabetic subjects with lower extremity amputation and a group of diabetics without these complications — through evaluating toe blood pressure (TBP), toe-brachial index (TBI) and pulse wave velocity (PWV); also, by comparing peripheral and autonomic nervous system integrity between these groups — through sensory, nerve conduction, needle-examination and autonomic function assessment. Study design: A cross-sectional, descriptive and comparative pilot study. Setting: Pretoria Academic Hospital. Participants: Three groups of ten patients consecutively selected from diabetes and diabetic foot clinics — ten with chronic lower extremity ulcers, ten with healed lower extremity amputations and ten diabetic controls. Methods: Assessment of peripheral and autonomic neuropathy included evaluation of 5.07/10-g monofilament sensation, vibration perception (using a 128Hz tuning fork), nerve conduction and electromyography, cutaneous autonomic response and heart rate variability (expressed as an Expiration: Inspiration (E:I)-ratio). For evaluation of vascular status, we obtained the photo-plethysmographically-derived TBI and assessed carotid-femoral (CF) and carotid-radial (CR) PWV. Sample sizes for future studies were calculated through a nomogram for three-group comparisons, ANOVA, simulation and log-transformation of non-parametric data. Results: Absence of vibration perception in at least one leg, with significant p-values of 0.000 at toe-, and 0.027 at medial malleolus- level, occurred more frequently in the amputation, than in the control group. For the total bilateral monofilament count a statistically significant difference between groups was demonstrated (p-value 0.043). Peripheral neuropathy based on abnormality of at least one conduction attribute in at least two distinct nerves, the E:I-ratio, assessment of cutaneous autonomic responses and TBI, by worsening across groups, seemed to display a correlation with severity of lower limb complications, but without statistically significant results. For CF- and CR PWV, the lowest values were observed in the amputation group. Sample size calculations based on our TBP, TBI, vibration and monofilament results, lead to a proposed equal group size of between 34 and 103 for future three-group comparisons using these outcomes measures. Should PWV be included, the group size would have to be between 160 and 222. Conclusions: This study confirmed the usefulness of monofilament sensation and vibration perception assessment in identifying diabetic patients with differing degrees of lower extremity risk. Also, due to the large differences between groups, it demonstrated the effectiveness of these measures to display differences between groups, even in the event of very small sample sizes. The tendencies to worsen across the three groups, of the E:I -ratio, peripheral neuropathy based on nerve conduction, and the TBI, will have to be re-examined in a study with larger sample size. In order to demonstrate statistically significant CF- and CR PWV results, a larger sample size may also be required. / Dissertation (MSc (Clinical Epidemiology))--University of Pretoria, 2007. / Clinical Epidemiology / unrestricted

No abstract available / Dissertation (MEd (CIE))--University of Pretoria, 2007. / Curriculum Studies / unrestricted

Child abuse is a problem that affect Thohoyandou Area, Ha-Tshivhasa in Limpopo Province. The aim of this research is to add value towards unfolding negative techniques regarding child abuse at the initiation schools, especially of those who suffered the consequences of ritual rites and primitive beliefs. The research documents will formulate guideline for the church leaders and social workers rendering services concerning child abuse. In addition to this, the research is aimed at rediscovering a system in which the children can be protected against any element of abuse. The research document wil be used as a guiding tool to the investigators attached to the South African Police Service, who investigates cases of child abuse. The method used in this investigative and evaluative exercise was that of personal interviews with initiates, victims= parents, community leaders, church leaders, christians and the reading of christian education literature. What came out of this investigation is that, indeed, most of the children are abused at the initiation schools. The findings are that, boys are tracked and hijacked to go to the schools for genital circumcission. By way of unpacking the findings, it should be said that there is a little concern from relevant roleplayers, namely; churches, social workers, the police and the entire community, regarding the child abuse that takes place at the initiation schools. Incidents that took place at the initiation schools are, however, not investigated in most of the inatances. Over the years, initiation schools were never guided and channelled by the government. This has led to assault, malicious damage to property and kidnapping. With the implementation of strategies laid down in Chapter 4 and 5 of this research, the situation at Ha-Tshivhasa villages regarding the initiation schools, can be remedied, and effective christian counselling, social worker service and investigation by the police will be embraced. / Dissertation (MA (Theology))--University of Pretoria, 2006. / Practical Theology / unrestricted