This study analysed why children under four years old were admitted to care, and whether they suffered harm due to abuse or neglect, based on file documentation regarding all 175 admissions, involving 129 children and 93 mothers, by one Ontario Children's Aid Society between 1992 and 1996. Using the Ontario Child Welfare Eligibility Spectrum to classify reasons for admission, more admissions were due to risks defined under Caregiver Capacity than Harm by Commission or Omission. Mothers' background and lack of resources were common factors. Evidence of harm was often hard to establish but was rated as clear or extreme in 12% of cases. Differences related to fathers' status, number and age of children in the home, and history of agency involvement were found between cases where children suffered severe harm due to abuse or neglect, and cases where they did not, but these differences were not statistically significant.

Quantitative soil ingestion studies employing a mass balance tracer approach have been used to determine soil ingestion rate for use in human health risk assessments (HHRAs). Past studies have focused on soil ingestion in populations living in urban/suburban environments and the results have been highly variable. Moreover, there is a paucity of reliable quantitative soil ingestion data to support human health risk assessments of other lifestyles that may be predisposed to ingesting soil, such as indigenous populations following traditional lifestyles. Thus, the primary objective of the research was to determine if populations following lifestyles typical of traditional land use practices in rural or wilderness areas ingest more soil than populations living in urban or suburban environments. Further, the research investigated the use of alternative mass balance tracers, specifically isotopes of the 238U and 232Th decay series, to reduce soil ingestion estimate variability. Mass balance tracer methods were developed and validated in a pilot canine study, and methods using isotope tracers were adapted to permit quantification of sediment ingestion in the benthic fish Moxostoma macrolepidotum (Shorthead Redhorse Sucker). A pilot human soil ingestion study of 7 subjects from an Aboriginal community in British Columbia was conducted over a 3-week period. The mean soil ingestion rate calculated using the daily means of the 4 elemental tracers with the lowest food-to-soil ratios (i.e., Al, Ce, La, Si) was observed to be approximately 74 mg d-1 (standard deviation 91 mg d-1), The median soil ingestion rate was 60 mg d-1, and the 90th percentile was 196 mg d-1. These soil ingestion rate estimates are higher than those currently recommended for HHRAs of adults, and higher than those obtained in most previous studies of adults. However, the estimates are much lower than the earlier qualitative assessments for subsistence lifestyles (i.e., 330-400 mg d-1). The study results also demonstrated that isotopes of the 238U and 232Th decay series radionuclide are not reliable mass balance tracers for estimating soil ingestion in humans; however, they may be useful for quantifying soil and sediment ingestion in wildlife.

Thesis (Ph.D.) - Carleton University, 2007. / Includes bibliographical references (p. 134-151). Also available in electronic format on the Internet.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 169-183).

Thesis (Ph. D.)--University of California, San Diego, 2006. / Title from first page of PDF file (viewed September 20, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 125-132).

Thesis (M.S.)--Purdue University, 2002. / Includes bibliographical references (leaves 52-56).

Flood events have caused detrimental impacts to humans' lives and anthropogenic climate change is anticipated to exacerbate the impact. It has been recognized that a long-term planning through risk-based optimization of flood defence will lead to a cost-effective solution for managing flood risk, but the prevailing assumption of stationarity may lead to an erroneous solution. In attempt to investigate the potential impact of the uncertain underlying statistical characteristics of extreme flow series to flood protection decisions, this research explores risk-based flood protection decisions in the context of climatic variability and change. In particular, the implications of persistence series and nonstationarity were investigated through hypothetical and real case studies. Monte Carlo simulation approach was adopted to capture the uncertainty due to the natural variability. For persistence model, AR(1) was integrated with the GEV model to simulate extreme flow series with persistence. To test the effects of nonstationary, GEV models with a linear location parameter and time as covariate were adopted. Rational decision makers' behaviours were simulated through a designed decision analysis framework. One of the main findings from the research is that the traditional stationary assumption should remain the basic assumption due to insignificant difference of the decisions' economic performance. However, exploration of the nonstationarity assumption enabled identification of options that are robust to climate uncertainties. It is also found that optimized protection of combined measures of flood defence and property-level protection may provide a cost-effective solution for local flood protection. Overall, the simulation and case studies enlighten practitioners and decision makers with new evidence, and may guide to practical enhancement of long term flood risk management decision making.

The quantification of information security risks is currently highly subjective. Values for information such as impact and probability, which are estimated during risk analysis, are mostly estimated by people or experts internal or external to the organization. Because the estimation of these values is done by people, all with different backgrounds and personalities, the values are exposed to subjectivity. The chance of any two people estimating the same value for risk analysis information is rare. There will always be a degree of uncertainty and imprecision in the values estimated. It is therefore during the data-gathering phase of risk analysis that the problem of subjectivity lies. To address the problem of subjectivity, techniques that mathematically deal with and present uncertainty and imprecision are used to estimate values for probability and impact. During this research a model for the objective estimation of probability was developed. The model uses mostly input values that are entirely objective, but also a small number of subjective input values. It is in these subjective input values that fuzzy logic and Monte Carlo simulation come into play. Fuzzy logic takes a qualitative subjective value and gives it an objective value, and Monte Carlo simulation complements fuzzy logic by giving a cumulative distribution function to the uncertain, imprecise input variable. In this way subjectivity is dealt with and the result of the model is a probability value that is estimated objectively. The same model that was used for the objective estimation of probability was used to estimate impact objectively. The end result of the research is the combination of the models to use the objective impact and probability values in a formula that calculates risk. The risk factors are then calculated objectively. A prototype was developed as proof that the process of objective information security risk quantification can be implemented in practice. / Prof. L. Labuschagne

The decisions made by Mental Health Professionals (MHPs) are of utmost significance for providing the highest quality care to service users. The assessment of risk is one of the pivotal processes that MHPs undertake frequently, as per government policy guidelines, and in order to safeguard patients and the public. Although Risk Assessment Proformas (RAPs) consume a proportion of MHP time and resources, very little research has been undertaken to address factors that might affect their most optimal utilisation in practice. Previous literature suggests that medical decisions, like decision making of other kinds, is fraught with difficulty including being susceptible to the influence of cognitive biases, pre-decisional affect, overconfidence, and subjectively held attitudes towards organisational policies and regulations. Specifically, the presentation of risk information can influence decisions. It has also been suggested that anxiety has the capacity to elicit risk aversive responses, and that overconfidence and negative attitude may lead to complacency in undertaking policy-led responsibilities and produce non-compliance for the same. However, much of what is known about medical decision making has been gleaned from outside of context of mental health. As such, the current programme of research aimed to explore decision making in mental health settings and with a view to raise awareness of the complexity of decision making amongst MHPs. The implementation of quantitative and qualitative techniques (studies 1 and 2) revealed negative attitudes from psychiatrists towards Risk Assessment Proformas (RAPs), which are essentially structured decision making aids. Psychiatrist, compared to other MHPs, spent less time completing RAPs, which may reflect their differing attitudes towards their usefulness, something that was consistently emphasised during in-depth qualitative exploration. It was also found that experience was an additional differentiating factor between MHPs. Relationships between experience and other factors such as anxiety, confidence and complacency were found via conversations with MPHs, experience members of staff being less inclined to provide comprehensive and detailed accounts of service user risk in RAPs. This is problematic since although there is, in the UK, a policy led requirement that RAPs are completed for each service user, it is clear that there are inter-professional variations in how RAPs are being used and this acts to inhibit the best information sharing between all those involved in patient care. Following previous work in the area of cognitive bias and its influence upon general and medical decisions, a clinical vignette was also developed (study 3) to establish whether the presentation of risk information influences psychiatric admission decisions. The current findings supported previous work in that decisions were susceptible to the framing effect. The findings here, and previously in the literature, reveal a necessity for MHPs to be informed of bias in decision making in an attempt to improve objectivity in risk assessment practices. The unearthing of the framing effect also further signals the need for proper use of RAPs, where many MHPs may not be using them to their full potential - i.e. an aid to the systematic consideration of a range of information about a service user. The final part of the thesis (study 4) turned to the piloting of an educational module incorporating content around the factors affecting decision making in an attempt to raise awareness amongst MHPs. The rationale being better awareness of the complexity of decision making may act to enhance decision making processes. Pre and post intervention analyses revealed an improvement of baseline to follow-up knowledge of decision making bias and statistical concepts and this knowledge was maintained to a moderate level at four weeks follow-up. Although individuals maintained their susceptibility to the framing effect, the bias was less prevalent in those who knew of its presence before taking part in the study. Overall the findings give some support to the use of education as an approach to raising awareness about decision making processes in MHPs, although what remains to be seen is whether such education acts to bring about changes in behaviour - for example, different use of RAPs. The PhD programme suggests that MHPs are just as susceptible to cognitive biases, such as the framing effect, as has been demonstrated in both general population and other groups of health practitioners. At the same time, attitudes to RAPs differ depending on exact job role, which psychiatrist being least likely to spend time on their completion and reporting them as a tool for noting decisions reached as opposed to an aid to the process. This acts reduce the quality and quantity of reported information shared with colleagues about a service user. It is possible that MHP behaviour aligns with general attitude-behaviour models, such as the Theory of Planned Behaviour. As such, whilst the current work has demonstrated that educational interventions may act to improve awareness of decision making processes and their influences, further research would benefit from considering if these types of approach affect actual behaviour. For example, improved used of RAPs as decision-aids, reduced susceptibility to framing effects, consciousness around how information is represented in RAPs given knowledge of how the information may be used by others.

M.Sc. (Zoology) / Viticulture is an important agricultural practice in many countries. The long term use of pesticides in vineyards has resulted in increased concentrations of such pollutants in sediments, water and other environmental compartments. Mitigation measures in agriculture, especially vineyard agriculture, are a prerequisite to the sustained integrity of the natural environment, and specifically the aquatic environment. Mitigation presents itself in the form of water bodies, riparian buffer strips, ground vegetation cover, grassed field paths, natural or artificial wetlands and modification of pesticide application rate. However, to our knowledge no studies exist which highlight the state of dams related to viticulture or the use of mitigation measures, in South Africa. The study aimed to quantify the cumulative risk posed to dams on wine farms and the effect of pesticides (fungicides, herbicides and insecticides) on aquatic ecosystems while evaluating the use of mitigation measures in South African viticulture. Epilithic diatom community structure assessment and frustule abnormalities; zooplankton and macroinvertebrate community structure assessment, and characterization of mitigation measures were carried out at nine representative study sites on wine farms in the Western Cape, South Africa. Pesticide risk assessment models PRIMET and PERPEST were employed to assess the risk that pesticides pose at each site from available data. The Relative Risk Model was used to assess the risk posed to identified Risk Regions. Different risk categories were observed across the sites from PRIMET and PERPEST, ranging from no risk to high risk for specific pesticides and relative risk among the risk regions was assessed. Diatom community structure displayed spatial and temporal variability between sites as well as observable diatom frustule abnormalities due to pesticide input. Zooplankton and macroinvertebrate communities displayed variability spatially as well as temporally and this was linked to the presence of pesticides confirming the predictions from PRIMET, PERPEST and the RRM.