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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
291

Validation and implementation of an ecological risk assessment (ERA) framework for pesticide use in the Vaalharts irrigation scheme

Malherbe, Charl Wynand 25 November 2013 (has links)
D.Phil (Aquatic Health) / Pesticides have been used to control and eliminate agricultural pests for many years thereby increasing crop yield in agriculture; however, the increasing human population worldwide has put increased pressure on agriculture to produce food. This is especially true in developing countries where the population growth has exceeded the predicted growth. Agriculture has therefore become more reliant on pesticides to increase the crop yield to meet the food demand. Many of the pesticides that are used in developing countries are not well studied in these countries and only limited information on their effects on the local environment is known. The information that is available is often from temperate regions and the effects of the pesticides in more arid, subtropical areas are not known. This is especially true in South Africa where a limited amount of studies on pesticides and their effects on the environment have been completed. The problem developing countries (including South Africa) face is the lack of funding which limit the studies on pesticides. Thus, a method was developed in Sri Lanka and Thailand whereby the risk and effects of pesticides to the environment, specifically non-target organisms, can be estimated using an international database which contains predominantly temperate data of pesticides. The first time this model was tested in South Africa was on the Crocodile River (West) Irrigation Scheme in the North West province. This model is initially dependant on the input of information from local farmers on the usage of pesticides. The data were then combined with secondary data on the pesticide characteristics to establish a preliminary risk posed by the pesticides. This risk could then be validated through biological monitoring and the actual pesticide values measured in the environment. This current study was initiated to test these probabilistic models in another part of South Africa with a more arid climate. The Vaalharts Irrigation Scheme (VHIS) comprises an area of 40 000ha where intensive agriculture activities take place and pesticide use is evident. The water for the irrigation scheme is transferred from a weir in the Vaal River to various irrigation canals and dams downstream. Water is then pumped out of the dams to irrigate the various crops. The runoff and drainage water is routed to drainage canals that return to the Harts River. The main crops in the area are wheat, maize and groundnuts, and a wide range of pesticides are used from the time the crops are planted until they are ready to be harvested. The current study was based on the Crocodile (West) River study in terms of the methodology followed, to further validate the use of the risk assessment methodology in southern Africa. Based on a situation analysis of the study area the following two hypotheses were formulated: the predictive and integrated risk models can be used to assess the ecological risk of pesticides when applied on the VHIS; and the risk information generated with these models can be communicated in an effective manner by using a Decision Support System (DSS).
292

Mass Balance Tracer Techniques for Integrating in situ Soil Ingestion Rates into Human and Ecological Risk Assessments

Doyle, James January 2012 (has links)
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.
293

Perceptions of risk to water environments in the lower Fraser basin, British Columbia

Cavanagh, Nigel Steven 05 1900 (has links)
The following thesis presents the results of a two year study that addressed lay perceptions of the risks to the water resources of the Lower Fraser Basin, British Columbia. Studies of this nature are important because by clarifying public perceptions, risk communication policies as well as land and water resource use plans that accommodate people's concerns can be developed appropriately. The study was based on a written survey that was administered to 183 lay subjects in four communities within the Lower Fraser Basin. Sixteen experts participated in a portion of the survey. Analysis involved the determination of how people perceive distinct human activities in terms of the risk each may pose to the health of aquatic ecosystems. Further analysis compared these perceptions to those of specialists in the aquatic sciences. The thesis is structured as a collection of three papers that examine different aspects of the study. The First paper provides a review of the overall data set, while the remaining two papers address related subsets of the data. One paper reviews perceptions of activities that cause eutrophication problems and the other reviews perceptions of forest industry activities. The results demonstrated that people tend to view risks to water environments in a multi-faceted fashion. Four factors were found to influence people's general perception of risk and the need for regulation of the activities that were perceived to pose the risk. These factors were termed Ecological Impact, Human Benefit, Controllability and Knowledge. Another significant result was the fact that there were often striking differences between the views of the lay sample and those of the expert sample. Some activities were perceived by the lay sample as posing substantial risk while the experts did not view this to be the case. Alternatively, for some activities, the reverse scenario occurred. Accordingly, there were differences in judgements between the two groups as to the degree of regulation that should be imposed on the respective activities. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate
294

Evaluation of an Opioid Risk-Assessment Screening Tool

Guerra, Jacquelyne 01 January 2018 (has links)
According to the Centers for Disease Control and Prevention, prescribers should evaluate risk factors related to opioid use prior to initiation of opioid medication. The practice problem in this DNP project was that providers failed to consistently assess patients with complaints of pain for risk of opioid misuse and/or abuse prior to initiating opioid medication. An opioid risk-assessment screening tool (ORAST) has the potential to identify patients at high risk for opioid misuse and/or abuse. The purpose of this Doctor of Nursing Practice project was to identify and introduce an ORAST and then develop a policy to guide providers in its use in an ambulatory care clinic. Rosswurm and Larrabee's model for evidence-based practice served as the framework that helped guide project development. Evidence in the literature review supported The Opioid Risk Tool (ORT) as the most appropriate tool for the clinic. An 11-member project team voted unanimously for the ORT and to develop a policy to guide the use of the tool in the clinic. The ORT and its policy were evaluated by the team using the AGREE II Instrument. The team agreed that the ORT and its policy should be implemented into their practice setting (64% strongly agreed and 36% moderately agreed). A summative evaluation supported the Doctor of Nursing Practice student leadership of the project. Use of an ORAST has the potential to create positive social change by reducing the number of prescribed opioid by assisting providers in determining a patient's plan of care based on the patient's level of risk for prescription opioid misuse and/or abuse. Patient outcomes may be improved through reduction in opioid misuse and/or abuse.
295

A Methodology for Cyberthreat ranking: Incorporating the NIST Cybersecurity Framework into FAIR Model

Bakare, Adeyinka A. 09 June 2020 (has links)
No description available.
296

Reasons for the admission to care of preschool children using the Ontario Eligibility Spectrum

Murphy, Lorenzo. January 2001 (has links)
No description available.
297

Exploring the Intersection of Dementia and Violence Risk Assessment

Klugiewicz, Jamie S. 21 April 2023 (has links)
No description available.
298

Reduced Order Modeling of Dynamic Systems for Decreasing Computational Burden in Uncertainty Quantification

Cohn, Brian E. 12 October 2018 (has links)
No description available.
299

A Comparison of Dynamic and Classical Event Tree Analysis for Nuclear Power Plant Probabilistic Safety/Risk Assessment

Metzroth, Kyle G. 22 July 2011 (has links)
No description available.
300

Bedömning av ungdomars behov av stöd inom den sociala barn- och ungdomsvården : En studie baserad på beslutsunderlag enligt BBIC / Assesment of young people’s need for support in social child and youth care : A study on decision-making documents according to BBIC

Khan, Saera January 2021 (has links)
Social workers are on a daily basis faced with difficult decisions in assessing risk of harm to children. The process requires appropriate competencies, and relevant and validated methods to ensure legal compliance. Risk assessments, knowledge of risk and protective factors, and the interplay between these factors, have been the focus in the development of procedures within social child and youth care since the implementation of Barns Behov i Centrum (BBIC) in 2006. Ahead of the revision of BBIC 2015, the evidence base was strengthened further, and the risk- need- and responsivity principles were introduced to support analysis and assessment processes.Taking a bio-ecological perspective, the purpose of this study has been to examine types of risk and protective factors identified in investigations of girls and boys aged 13-17 years, and how these are weighed in the social secretary's analysis and assessment of the child's needs according to the risk- need- and responsivity principles.The study is based on a thematic analysis of 30 decision-making documents according to BBIC, and the findings of the analysis are further illustrated with descriptive statistics.The findings highlight that analyses and assessments lack a holistic perspective of the development of children vis-à-vis parental abilities and other factors in the family and environment, and that a predominant proportion of identified risk- and protective factors are attributed to the youth in question. The findings also show that the risk- need- and responsivity principles are not drawn upon in analyses and assessments as intended.Conclusions: • Investigations of the youths’ needs have been conducted with a narrow focus on the child's development in the BBIC triangle, which means that the assessment ofneeds is constructed on the basis that the youths’ primarily are responsible for their own situation. • In the absence of a thorough implementation of the revised BBIC, a separate praxis with regard to the principles of risk- needs- and responsivity seems to have emerged, which in turn may hinder legal compliance in the assessment of childrens’ needs.

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