Background: This study compares three methodologies appropriate for the analysis of longitudinal time-to-event data. The Cox model is well researched and frequently used. Threshold regression, however, is relatively new and there are few articles describing its application in biomedical statistics. A linear mixed model provides an alternative interpretation of a continuous outcome rather than time to an event. A longitudinal study of the time to onset of diabetic nephropathy, a common complication of Diabetes Mellitus, is used to compare the three models with respect to their explanatory and predictive abilities and utilitarian value to researchers. Methods: The study entails a secondary data analysis of 1160 retrospective patient records, collected at a diabetic clinic at Kalafong Hospital, Pretoria. Model selection was based on current literature, backward elimination of insignificant variables (p>0.2) and the Akaike and Bayesian Information Criterion. Survival and hazard functions and ratios were determined for the survival data. Risk categories in the Cox model evaluated discrimination, while threshold regression predicted survival probabilities for specific patient profiles. The linear mixed model predicted albumin-creatinine ratio values, a marker for the diagnosis of diabetic nephropathy. Results: The Cox model, stratified by glucose control, gender, hypertension, type of diabetes and smoking status, had an AIC of 81 and was the most parsimonious model. Threshold regression, with an AIC of 1428, indicated duration of diabetes as a significant factor in the process of health deterioration. Individual variation in weight and total cholesterol amongst patients was accounted for by the linear mixed model, with an AIC of 3755. Conclusion: All three regression models provided valuable insight into underlying risk factors of diabetic nephropathy and should form part of a multi-faceted approach to analysing longitudinal survival data. / Dissertation (MSc)--University of Pretoria, 2014. / lk2014 / School of Health Systems and Public Health (SHSPH) / MSc / Unrestricted

The South African health system faces numerous challenges. A large majority of the population are dependent and have to contend with a dysfunctional public sector. The quality of care patients receive is severely compromised. Systemic factors, that are particularly prevalent in state facilities, exacerbate the problem. As a result, patient safety is endangered and many avoidable adverse events occur. These adverse events bring about grave consequences for the practitioner involved, the healthcare system with regard to the detrimental impact on resources and, most importantly, the patient. It must be acknowledged that many of the problems and institutional weaknesses that prevail in the public sector have been inherited. Recognising this, however, does not absolve the current administration, as many of the challenges are compounded by poor policy decisions and failures in crucial areas. This necessitates the need for a critical evaluation of proposed reforms. This dissertation conducts such an evaluation to investigate whether the National Health Insurance will adequately address the deficiencies of the existing system and ensure that South Africans have access to affordable, quality healthcare services. It is argued that there are many unanswered questions in the proposal as set out in the Green Paper. An insufficient case is made for the complete reform of the healthcare system. The adequacy and effectiveness of the NHI, as the preferred mechanism with which to achieve positive health outcomes, have not been established. There are also serious concerns about the affordability thereof as well as the transparency of the process. Medical malpractice is also investigated. The dissertation provides an overview of the current regulatory and civil liability framework, before evaluating the current malpractice situation. The increasing costs and frequency of claims have been identified as a threat to the existing healthcare system and the successful implementation of the NHI. The dissertation assesses the problem, by considering the extent, effects and causes of increased malpractice litigation. It is argued that the existing malpractice system may be inadequate at promoting and ensuring quality care and patient safety. Reforms that align the objectives of the health system with those of the medical malpractice system should be implemented. Conventional reforms that would merely alter the current system will be insufficient. Fundamental reforms should thus be considered. A patient-orientated approach will be crucial in this regard. Patients are the most severely affected by malpractice and will have to contend with the consequences of malpractice litigation as well. Reforms, seeking to ensure that patients receive compensation whilst making healthcare safer, should be central to any discussion. Concrete research is necessary. Information on South Africa’s health system as it relates to the burden of iatrogenic injury and the causes and avoidability thereof should be studied. The malpractice system should also be scrutinised. Reliable data is required on the number of malpractice claims filed, the causes, costs involved and the difficulties experienced in obtaining compensation. Policy decisions that would ensure that quality care is provided and that patient safety is emphasised must be informed by the necessary inquiries. / Dissertation (LLM)--University of Pretoria, 2014. / lk2014 / Public Law / LLM / Unrestricted

The ordinary local Cameroonian just like people everywhere experiences a lot of evil and suffering in acts such as violence, abuse, murder, poverty, sicknesses, and death. But in Cameroon the experience of suffering seems more intense because of the constant blame on people and other things for causing the pain. This then makes the suffering more painful, provoking negative counter consequences. This study attempts to explore Moltmann’s understanding of suffering in order to apply to the local Cameroonian context and give it a fresh perspective and insight that could possibly inform and/or shape a theologically grounded approach on the issue of suffering; one that could shape the traditional as well as the current theological perspective. Methodologically, this study will attempt a fresh perspective and approach towards suffering that will enable the local Cameroonian to think and act differently when situations of evil that cause suffering arise. The study will be approached in three different ways. First, we shall probe into the Cameroonian context and be conversant with some of its practical realities; history, religion, culture, and some realities pertaining to suffering. Secondly, we shall attempt a detailed explanation of the concepts of evil and suffering in humanity and the rest of creation and touch on the issue of theodicy that remains an on-going discussion and struggle as long as evil persists in the world. Thirdly we shall delve into Moltmann’s reflection on evil and suffering as expounded in his theology of the cross as a light that may illumine as well as orient some beliefs in the local Cameroonian context. One such belief concerns the environment. Local Cameroonians are not very conscious of the natural environment, i.e. the soil, wildlife, vegetation and atmosphere. These are treated with absolute dominance due to the notion that they are there to serve human needs. Some of the evil suffering in Cameroon emanates from this view of the environment, resulting in suffering and evil that affects people and nature. As such any study of evil and suffering in the local Cameroonian context will be incomplete unless suffering in the rest of creation is taken into consideration. / Dissertation (MA)--University of Pretoria, 2014. / lk2014 / Dogmatics and Christian Ethics / MA / Unrestricted

In the past, contaminated soil as a source for water contamination has been largely neglected from the South African legislation. Inconsistent evaluation and remediation of contaminated sites have resulted in many sources of water contamination not being sufficiently addressed. The Draft National Norms and Standards for the Remediation of Contaminated Land and Soil Quality (GN 233 of 2012) (henceforth Norms and Standards) was published for comments and suggestions in August 2012. A number of uncertainties have been identified that may impact on the successful implementation of the Framework and the Norms and Standards. Some of the issues are related specifically to the setting of soil screening values (SSV) for protection of water resources. There is no particular method specified to determine the soluble fraction of contaminants in soil. In a phase 1 assessment SSVs are used to judge whether constituents present in the soils are at concentrations high enough to pose a potential risk to the receiving environment. With the determination of the SSV a known water quality standard is converted to a total concentration by making use of a dilution factor and partitioning coefficient (Kd). The proposed Kd values in the Framework are surrounded by uncertainties and information regarding Kd values for South African soils are limited. In addition, the Framework does not take into account the natural background concentration of soils to differentiate between anthropogenic and natural contamination. Setting appropriate extraction method plays the key role for an objective and standardised initial assessment of soluble concentrations in the soil. Similarly, the selection of appropriate Kd values based on soil properties minimizes the uncertainties during the estimation of SSV. Appropriate screening of contaminated land is imperative to the registration of contaminated land and has significant implications for industry, government and the environment. The aims of this study were: a) to assess fast and simple analytical methodologies which can be performed by a commercial laboratory to mimic the standard saturated paste extraction method to determine soluble metal concentration in soils, b) to determine Kd values for selected South African soils in 10 soil horizons, and c) to determine baseline concentration ranges for selected soluble contaminants to assist in the setting of appropriate soil screening values for the protection of water resources. The study will test the hypothesis that a 1:2.5 (soil:water ratio) water extraction could better mimic the standard saturated paste extraction than the 1:20 ratio, commonly used in USA. The 1:2.5 ratio can be done by most commercial laboratories and gives a better indication of the pore water quality. To assess analytical methods, four extraction methods (1:2.5, 1:5, 1:10 and 1:20 soil:water) were tested against the standard saturated paste extraction using three trace metals (Cu, Pb and V). These three metals were selected based on reactivity and environmental abundance. Lead and Cu are B type metals which complex readily with organic material and are generally more environmentally toxic. Anthropogenic activities are increasing enrichment of B type metals in the environment. Vanadate is an A type metal and is redox sensitive. Its association with the Bushveld complex was the reason for its inclusion in this study. The baseline soluble concentrations of Cu, Pb, and V were determined for selected 100 South African soils using the extraction method selected above. The Kd values of Cu, Pb, and V were determined for selected 10 soil horizons (1:1 clay dominated A horizon, Vertic soil dominated by 2:1 clay minerals, Yellow oxidic / Plinthic (Soft plinthic B horizon), low clay red oxidic B horizon, red oxidic B horizon, plinthic B horizon, gleyed horizon (G horizon), melanic A horizon, orthic A horizon with high organic content (OC) and E-horizon) using a batch method. For each constituent three different metal concentrations were added to each of the soil horizons. After extraction the concentration in the solution was used to determine the amount of metal sorbed to the soil. Considering the standard saturated paste extract as a bench mark, the 1:2.5 soil:water ratio extraction gave more representative soil pore water quality for Cu, Pb and V in the low to medium concentrations. Therefore, the hypothesis was accepted. It was also apparent that the Kd values selected for the Framework are not representative of typical South African soils. The Kd values for Cu range between 12.7 and 19044 L kg-1. These values exceeded the value of 10 L kg-1 provided by the Framework in all soils. For V the Kd values (10.5 – 865 L kg-1) in all soils were lower than the value of 1000 L kg-1 specified in the Framework. For Pb, the Kd of 100 L kg-1 as indicated in the Framework is not representative of soils found in South Africa. For Pb, low clay content, weathered soils have lower Kd values, whereas higher clay content soils have Kd values up to 4 orders of magnitude higher than the Kd in the Framework. Therefore, due to the large variability in Kd values, a single value cannot be used for all soil types. To conclude, the 1:2.5 soil:water ratio was found to be more representative to the soil pore content especially in the low to medium solute concentrations. The study also showed that a single Kd value cannot be used across soil types. The Kd values currently used in the Framework have low representativity of the South African soils. In the meantime, the Kd values for Cu, Pb, and V generated from this study for selected South African soil horizons could be used by the framework. There is, however, a need to develop local Kd values of contaminants across soil types. / Dissertation (MSc)--University of Pretoria, 2014. / lk2014 / Plant Production and Soil Science / MSc / Unrestricted

Read abstract in the document / Dissertation (MA)--University of Pretoria, 2014. / lk2014 / Centre for Augmentative & Alternative Communication (CAAC) / MA / Unrestricted

The lack of access to agricultural credit is a constraint to the development of the small-scale segment of the agricultural sector. The challenge for formal financial institutions is to provide agricultural credit that meets the unique demands of the entire agricultural sector (both commercial and emerging sectors). Although small-scale farmers face a number of challenges, lack of capital for investment contributes significantly to the lowering of smallscale farmers’ productivity levels. The challenge of access to agricultural credit from formal financial institutions is longstanding. Although some improvements have been made, a large proportion of small-scale farmers are yet to be reached by these institutions. One of the ways in which formal institutions can promote access to credit for small-scale farmers is to adopt best practices in lending. The study sought to establish whether formal finance institutions in South Africa adhere to best practices in their agricultural lending operations for small-scale farmers. A review of literature indicates that there are countries whose formal financial institutions have achieved some success in improving access to finance for small-scale farmers. Hence, it is important to find out what these institutions have done, particularly the best practices they have adopted in this regard. Best practices in agricultural finance are the innovative methods/techniques/and procedures that address the supply- and demand-side constraints and challenges (from both the finance and agricultural sectors’ perspectives) and thus improve the levels of access to agricultural finance. The response of formal finance institutions to the risks and uncertainties inherent in the sector is to enforce stringent collateral requirements that are restrictive for small-scale farmers. The study adopted a qualitative approach that utilised primary and secondary information obtained from reports, manuals and other relevant documents in the public domain as well indepth interviews with key role-players from the major formal finance institutions. The results of the study revealed that formal financial institutions in South Africa have not found appropriate delivery modalities that encourage and support agricultural finance accessibility among small-scale farmers. There have been considerable developments in terms of product type and product design in order to meet the demands of small and medium enterprises as well as agricultural clients. However, there still seems to remain gaps in terms of the different categories of emerging farmers that can be adequately financed by formal finance institutions. The loan appraisal process in formal finance institutions is based on the bankability of the farm enterprise and there is a heavy reliance on ‘traditional’ collateral requirement. There are few examples of collateral alternatives and substitutes that are used in practice and are usually of lesser value but also burdensome on the part of formal financial institutions (thus, a need for equity contributions remains necessary). Given the nature of the formal finance institutions considered in the study viz. commercial banks and the Land Bank; with their highly competitive and sophisticated corporate environment, and operations underpinned by a strictly business approach – there is little room left for a developmental agenda in terms of their lending practices. Though private sector institutions play a significant role in theSouth African economy, the role of the state remains quite large with regard to the ambitionof a developmental state. It is within this dynamism that the public-private dichotomy of agricultural finance arises. There is also a gap in terms of providing the much needed non-financial support, such as access to markets, technical skills, or collateral alternatives. The environment within which formal finance institutions provide agricultural credit has changed, and agricultural lenders need to identify the arising opportunities in small-scale farmer development. The current status quo in small-scale agricultural lending best practices in South Africa leaves much room for development. / Dissertation (MInst(Agrar))--University of Pretoria, 2014. / lk2014 / Agricultural Economics, Extension and Rural Development / MInst(Agrar) / Unrestricted

The recent increase in seismic activity in the Central Rand Basin of South Africa was investigated using two different approaches. The closure of mines throughout the basin has left a large underground void behind that has rapidly filled with water, polluted by mine workings. There is concern over the possible triggering of a large earthquake beneath the city of Johannesburg. Questions surrounding the mechanism and nature of the seismicity still persist. Two approaches were selected to uncover early clues about the seismicity and possibly shed some light on future expectations. The first approach was an analysis of the frequency-magnitude distribution (b-value) over time, while the second approach was an attempt at building a 3-dimensional geomechanical model to describe a possible driving force behind the seismicity. Results from a temporal b-value analysis show a strong correlation with a drop in the b-value and the onset of the largest events in the database. This is explained by the relationship between the b-value and physical properties of the rock mass. An overall decrease in the b-value was estimated since flooding started, indicating a shift towards a higher proportion of larger events. The 3-dimensional geomechanical model provided a measure of the stresses and shear displacements that occur where geological discontinuities intersect the mine workings. This was compared to previous estimates of stress measurements in the mines and maximum possible magnitude estimations. The spatial distribution of recent, relocated seismicity was described in terms of the results from the model, which identified unstable geological features. The distribution of these features matched the seismic clusters that were observed, which provided some insight into the current tectonic setting of the Central Rand Basin. / Dissertation (MSc)--University of Pretoria, 2014. / lk2014 / Physics / MSc / Unrestricted

This dissertation tackles the current life insurance industry challenge to price and hedge minimum rate of return guarantees (MRRG) embedded in recurring-contribution life insurance contracts in a practical manner. The key contribution to the literature is to outline a practical approach to quantify and project the impact of dynamic hedging strategies for such options. MRRGs are typically very long-dated and as a result the validity of using typical financial economics options pricing models under incomplete market conditions remains a debate. However, life insurers need robust, practical solutions to assist them to manage market risk exposures for day-to-day solvency and income statement management. Literature specific to the topic of MRRG pricing and hedging over recurring-contribution life insurance products is sparse but Schrager and Pelssers’ significant contribution (Schrager and Pelsser 2004) provided a basis on which this dissertation was built. Schrager and Pelsser show these options to be analogous to Asian options written over a stochastically-weighted average of the underlying unit fund price. This dissertation demonstrates the effects of stochastic interest rates on MRRGs increase with maturity, as shown by Schrager and Pelsser. Consequentially, users should be aware of the effect and limitations of their choice of interest rate model when pricing MRRGs. Sensitivities for the various maturity terms of MRRG benefits are shown and provide readers with insight into the factors driving the dynamics of such options. A simple dynamic hedging program is outlined and projected under real-world evolutions on a daily basis, thus allowing the effectiveness of the hedging program to be tested. / Dissertation (MSc)--University of Pretoria, 2014. / lk2014 / Mathematics and Applied Mathematics / MSc / Unrestricted

Dissertation (LLM)--University of Pretoria, 2014. / lk2014 / Public Law / LLM / Unrestricted

Bulk materials handling systems are extensively used within the mining and minerals industry. Due to the nature of the mining environment, the support structures for these systems are often exposed to special and/or accidental loading conditions. This unfortunately leads to a fairly high incidence of structural damage or failure being experienced within the mining industry, notwithstanding design compliance with appropriate standards. Over the past few decades reputable mining companies have acknowledged the necessity for more conservative structural designs and this has led to the development of design rules for permanent structures which are used in conjunction with national and international design standards. The design of mobile continuous bulk handling equipment is governed internationally by the ISO 5049-1 (1994) Standard, except in Australia where AS 4324-1 (1995) is generally utilised. The study investigates a number of catastrophic failures of mobile bulk materials handling (BMH) equipment to identify the typical root causes and their complex interaction in these disastrous events. A retrospective view is taken of the processes followed during the investigation of the main case study to develop a methodology for future failure investigations. Brief case studies are made to demonstrate the shortcomings of the ISO 5049-1 (1994) Standard, which currently provides no rules or guidelines for machine protection systems. The aim of the study is ultimately to improve structural safety on future mobile BMH equipment designs, which does not necessarily imply a more conservative design approach, but rather that design loads and conditions be correctly assessed. The revision of ISO 5049-1 (1994) is subsequently proposed to provide specific rules and guidelines pertaining to machine protection systems. Other focus areas for consideration are also covered. It is furthermore recommended that the structural design engineer should play a more prominent role during the final acceptance of mobile BMH equipment and handover to the owner. A systems design approach integrating the respective engineering disciplines and based on a comprehensive risk assessment, is required. / Dissertation (MSc)--University of Pretoria, 2014. / lk2014 / Civil Engineering / MSc / Unrestricted