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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.
631

Novel Approaches to Exposure Assessment and Dose Response to Contaminants in Drinking Water and Food

Phetxumphou, Katherine 23 April 2018 (has links)
In the fields of water safety, food safety, and public communications, the overarching goal is to improve public health. Thus, this dissertation focuses on risk assessment and applying novel methods for exposure assessments and dose responses to contaminants in drinking water and foods. Factors that greatly impact contaminant exposures and human dose response include: population susceptibility (i.e., healthy adults or children), different routes of exposures (i.e., ingestion or inhalation), carrier matrices (i.e., water or food), and intricacies of chemical and biological mixtures. Chemical spills, such as the 2014 crude MCHM spill in Charleston, WV, revealed the complexities of both minor and major components in the chemical mixture. Slight shifts in geometric structures (isomers) can affect the fate and transport properties of the chemical mixture and as a result, the level of human exposure and dose response to each component in the chemical mixture. Odorous properties of both minor and major components can affect human inhalation exposure, especially during showering, and can be as detrimental as the ingestion route exposure and are different for healthy adults versus for children. Food contaminants, such as Shiga toxin producing Escherichia coli (STEC) in beef products, can be mitigated through a quantitative microbial risk assessment (QMRA) framework that follows a farm-to-fork model. Methods to ensure greatest microbial reduction include: employed intervention strategies at slaughter plants (i.e., water washing of beef carcass), improved cooking times and temperature methods at the consumer and retail level, and assessed minimum effective dose response modeling for different population susceptibilities. Current public communication tools, including the Drinking Water Taste-and-Odor Wheel or Consumer Confidence Reports (better known as water quality reports), should be redeveloped to uphold water safety. Furthermore, public health campaigns that uses social media strategies and informative websites can better educate the public on food contaminants. Ultimately, the objective is to prevent human illnesses due to water contaminants and foodborne pathogens and to bridge the communication gap between the consumers and the experts concerned with water and food safety. / Ph. D. / In the fields of water safety, food safety, and public communications, the overarching goal is to improve public health. Thus, this dissertation focuses on risk assessment and applying novel methods for exposure assessments and dose responses to contaminants in drinking water and foods. Factors that greatly impact contaminant exposures and human dose response include: population susceptibility (i.e., healthy adults or children), different routes of exposures (i.e., ingestion or inhalation), carrier matrices (i.e., water or food), and intricacies of chemical and biological mixtures. Chemical spills, such as the 2014 crude MCHM spill in Charleston, WV, revealed the complexities of both minor and major components in the chemical mixture. Slight shifts in geometric structures (isomers) can affect the fate and transport properties of the chemical mixture and as a result, the level of human exposure and dose response to each component in the chemical mixture. Odorous properties of both minor and major components can affect human inhalation exposure, especially during showering, and can be as detrimental as the ingestion route exposure and are different for healthy adults versus for children. Food contaminants, such as Shiga toxin producing Escherichia coli (STEC) in beef products, can be mitigated through a quantitative microbial risk assessment (QMRA) framework that follows a farm-to-fork model. Methods to ensure greatest microbial reduction include: employed intervention strategies at slaughter plants (i.e., water washing of beef carcass), improved cooking times and temperature methods at the consumer and retail level, and assessed minimum effective dose response modeling for different population susceptibilities. Current public communication tools, including the Drinking Water Taste-and-Odor Wheel or Consumer Confidence Reports (better known as water quality reports), should be redeveloped to uphold water safety. Furthermore, public health campaigns that uses social media strategies and informative websites can better educate the public on food contaminants. Ultimately, the objective is to prevent human illnesses due to water contaminants and foodborne pathogens and to bridge the communication gap between the consumers and the experts concerned with water and food safety.
632

Guidelines for Implementing Risk-Based Asset Management Program to Effectively Manage Deterioration of Aging Drinking Water Pipelines, Valves and Hydrants

Aprajita, Fnu 31 July 2018 (has links)
There is an unprecedented need to manage our deteriorating water infrastructure systems effectively to mitigate the enormous consequences of their premature failure such as loss of service, money, time, damage to other infrastructure, and damage to property. Most of the water utilities understand this need and are implementing asset management approaches and technologies to increase the overall service life of their assets. However, to indeed achieve sustainable water infrastructure systems, there is a requirement to implement a risk-based asset management program which provides a more comprehensive approach to manage these aging assets. A risk-based asset management program assesses and manages the risk of failure associated with the water infrastructure assets and helps water utilities in prioritizing their assets for renewal. This program identifies the critical assets for renewal and saves the money and time invested in the renewal of 'not so critical' assets. This research incorporates an extensive literature and practice review on risk-based asset management of pipes, valves, and hydrants. The risk-based asset management consist of the following four major components: (1) understanding the deterioration modes and mechanisms, (2) implementing risk assessment and management approaches, (3) implementing condition assessment approaches and technologies, and (4) implementing asset renewal approaches and technologies. This research aims to provide enhanced guidelines based on the EPA 10 step asset management program which will help water utilities in developing a risk-based asset management program as well as in improving their existing asset management program. This research combines the in-depth knowledge gained through a state-of-the-art literature review and practice review. The practice review is conducted to capture the real world application of the risk-based asset management through interviews with the water utilities across the united states. This research has also compiled the knowledge gained by already published case studies to provide a more comprehensive overview of the current practices and trend in the risk-based asset management of drinking water pipelines, valves, and hydrants. / Master of Science / America’s drinking water infrastructure is deteriorating and there is an unprecedented need to manage our deteriorating water infrastructure systems effectively to mitigate the enormous impacts of their premature failure such as loss of service, money, time, damage to other infrastructure, and damage to property. In order to achieve sustainable water infrastructure systems, there is a requirement to implement a risk-based asset management program which is a comprehensive approach to manage these aging assets. A risk-based asset management program assesses and manages the risk of failure associated with the water infrastructure assets and helps water utilities in prioritizing their assets for renewal. This program identifies the critical assets for renewal and saves the money and time invested in the renewal of “not so critical” assets. This research aims to provide enhanced guidelines based on the EPA 10 step asset management program which will help water utilities in developing a risk-based asset management program as well as in improving their existing asset management program. This research combines the in-depth knowledge gained through a state-of-the-art literature review and practice review. The practice review is conducted to capture the real-world application of the risk-based asset management through interviews with the water utilities across the united states. This research has also compiled the knowledge gained by already published case studies to provide a more comprehensive overview of the current practices and trend in the risk-based asset management of drinking water pipelines, valves, and hydrants.
633

Developing a systematic methodology to build a systems dynamics model for assessment of non-technical risks in power plants

AL Mashaqbeh, S., Munive-Hernandez, J. Eduardo, Khan, M. Khurshid, Al Khazaleh, A. 09 July 2019 (has links)
Yes / In a dynamic business environment like the energy sector, power plants face several complex risks, including both technical and non-technical risks. These risks are not isolated, as their impact may affect a series of interrelated risks. Those risks may change with time, which in turn, makes the strategic decision-making process less effective. Understanding the dynamic behaviour of a complex system is very important to achieve a more sustainable overall performance of the power plants. Thus, it is important to further develop a systematic risk assessment methodology that could help to identify and analyse the interdependencies among risks and to understand the dynamics of these risks in complex systems. This paper develops a system dynamics (SD) methodology to support the development of risk assessment models. This paper highlights the environmental perspective. The first step to develop a SD model will be applied, while the final SD model will be discussed in another paper.
634

Novel antibodies directed against the human erythropoietin receptor: creating a basis for clinical implementation

Maxwell, P., Melendez-Rodriguez, F., Matchett, K.B., Aragones, J., Ben-Califa, N., Jackel, H., Hengst, L., Lindner, H., Bernardini, A., Brockmeier, U., Fandrey, J., Grunert, F., Oster, H.S., Mittelman, M., El-Tanani, Mohamed, Thiersch, M., Schneider Gasser, E.M., Gassmann, M., Dangoor, D., Cuthbert, R.J., Irvine, A., Jordan, A., Lappin, T.R., Thompson, J., Neumann, D. 04 October 2015 (has links)
Yes / Recombinant human erythropoietin (rHuEPO) is an effective treatment for anaemia but concerns that it causes disease progression in cancer patients by activation of EPO receptors (EPOR) in tumour tissue have been contro- versial and have restricted its clinical use. Initial clinical studies were flawed because they used polyclonal antibodies, later shown to lack specificity for EPOR. Moreover, multiple isoforms of EPOR caused by differential splicing have been reported in cancer cell lines at the mRNA level but investigations of these variants and their potential impact on tumour progression, have been hampered by lack of suitable antibodies. The EpoCan consortium seeks to promote improved pathological testing of EPOR, leading to safer clinical use of rHuEPO, by producing well characterized EPOR antibodies. Using novel genetic and traditional peptide immunization protocols, we have produced mouse and rat monoclonal antibodies, and show that sev- eral of these specifically recognize EPOR by Western blot, immunoprecipi- tation, immunofluorescence, flow cytometry and immunohistochemistry in cell lines and clinical material. Widespread availability of these antibodies should enable the research community to gain a better understanding of the role of EPOR in cancer, and eventually to distinguish patients who can be treated safely by rHuEPO from those at increased risk from treatment. / Study was supported by the FP7-Health European commission EpoCan grant (282551).
635

Risk assessment formulation for nitrate leaching

Carter, E. Thomas Jr. 18 November 2008 (has links)
A framework for evaluating the risk of water pollution from the application of liquid dairy manure to agricultural fields was developed and applied. The GLEAMS (Groundwater Loading Effects of Agricultural Management Practices) (Ver 2.1) model was used to simulate NO₃-N leaching below the root zone for different land application rates of liquid dairy waste for fields in Georgia and Texas. Probability distributions of yearly-maximum nitrate concentrations were developed for each application rate at each site using the simulated nitrate concentrations. The probability of failure (exceeding 10 mg/L NO₃-N) for each application rate was determined from its corresponding distribution. An appropriate fine for farmers based on probability of failure for different land application rates was determined through economic analysis. The expected risk to farmers in monetary terms was determined for each application rate based on possible fines and the probability of failure. The monetary risk of nitrate leaching to ground water was compared to the social value of ground water. The probability of failure for liquid dairy waste application rates between 200 to 800 kg·N/ha/yr ranged from 0.0022 to 0.74 for Tifton, GA. The probability of failure for liquid dairy waste application rates between 0 and 1000 kg·N/ha/yr ranged from 0.00 to 0.85 for Overton, TX. The maximum application rate that was environmentally acceptable for both Texas and Georgia was 250 kg·N/ha/yr based on the probability of failure. Fines of $1100/ha and $700/ha for the Georgia and Texas sites, respectively, would provide farmers with economic incentives not to exceed an application rate of 250 kg·N/ha/yr. These fines resulted in risks to farmers of $814/ha in Georgia for 800 kg·N/ha/yr application rate and $595/ha in Texas for 1000 kg·N/ha/yr rate. This compares with a social value ranging from $860/ha to $1432/ha of clean ground water. / Master of Science
636

DEVELOPMENT OF A RESPONSE SPECTRUM MODEL FOR BIFENTHRIN USING JUVENILE CHINOOK SALMON (ONCORHYNCHUS TSHAWYTSCHA)

Knaub, Katie Jo 01 August 2024 (has links) (PDF)
Long-term declines in salmonid populations observed in California Central Valley have prompted efforts to enhance the understanding of how environmental stressors impact sensitive species. Bifenthrin, a current-use insecticide, has been consistently detected throughout the Sacramento-San Joaquin River Delta (Delta) and has been linked to detrimental effects in salmon. Traditionally, aqueous concentration is used in toxicological studies to evaluate the effects of pesticides on aquatic organisms, which assumes that concentration of the toxicant in water is a valid surrogate for dose. The critical body residue approach was established as an improved technique for assessing toxicity of hydrophobic contaminants, but there is a lack of data to support the application of this method in assessing risk of contaminant exposure in the environment. The current study creates a response spectrum model (RSM) demonstrating the relationship between internal residue and effects observed in Chinook Salmon from laboratory-based exposures. To develop the RSM, a series of behavioral and physiological endpoints were measured using bifenthrin-dosed Chinook Salmon to use with previously generated mortality data for incorporation in the model. The most sensitive endpoints were locomotion and shoaling behavior, followed by anxiety, growth, swim performance, upper thermal sensitivity, olfactory response, and lethality. The RSM endpoints were compared to bifenthrin residues in field-collected juvenile Chinook Salmon collected in 2019-2020 as part of our earlier studies. We found bifenthrin tissue residues were at similar levels to the most sensitive endpoints featured in the RSM, suggesting that bifenthrin exposure in the field is likely to cause behavioral effects to salmon as they out-migrate through the Delta. The developed RSM is a tool that could be used by water quality managers to evaluate the extent to which bifenthrin exposure may impact behavior and performance in juvenile salmon, providing a field-based verification of its effects on outmigration.
637

Exploring variation in implementation of multifactorial falls risk assessment and tailored interventions: a realist review

Alvarado, Natasha, McVey, Lynn, Wright, J., Healey, F., Dowding, D., Cheong, V.L., Gardner, Peter, Hardiker, N., Lynch, A., Zaman, Hadar, Smith, H., Randell, Rebecca 22 June 2023 (has links)
Yes / Falls are the most common safety incident reported by acute hospitals. In England national guidance recommends delivery of a multifactorial falls risk assessment (MFRA) and interventions tailored to address individual falls risk factors. However, there is variation in how these practices are implemented. This study aimed to explore the variation by examining what supports or constrains delivery of MFRAs and tailored interventions in acute hospitals. A realist review of literature was conducted with searches completed in three stages: (1) to construct hypotheses in the form of Context, Mechanism, Outcome configurations (CMOc) about how MFRAs and interventions are delivered, (2) to scope the breadth and depth of evidence available in Embase to test the CMOcs, and (3) following prioritisation of CMOcs, to refine search strategies for use in multiple databases. Citations were managed in EndNote; titles, s, and full texts were screened, with 10% independently screened by two reviewers. Two CMOcs were prioritised for testing labelled: Facilitation via MFRA tools, and Patient Participation in interventions. Analysis indicated that MFRA tools can prompt action, but the number and type of falls risk factors included in tools differ across organisations leading to variation in practice. Furthermore, the extent to which tools work as prompts is influenced by complex ward conditions such as changes in patient condition, bed swaps, and availability of falls prevention interventions. Patient participation in falls prevention interventions is more likely where patient directed messaging takes individual circumstances into account, e.g., not wanting to disturb nurses by using the call bell. However, interactions that elicit individual circumstances can be resource intensive and patients with cognitive impairment may not be able to participate despite appropriately directed messaging. Organisations should consider how tools can be developed in ways that better support consistent and comprehensive identification of patients' individual falls risk factors and the complex ward conditions that can disrupt how tools work as facilitators. Ward staff should be supported to deliver patient directed messaging that is informed by their individual circumstances to encourage participation in falls prevention interventions, where appropriate. PROSPERO: CRD42020184458. / This research is funded by the National Institute for Health Research (NIHR) Health and Social Care Delivery Research (HSDR) Programme (project number NIHR129488).
638

Risk, modernity and the discursive construction of pollution in 1970s and 1980s Hong Kong. / CUHK electronic theses & dissertations collection

January 2013 (has links)
Lam, Yee Man. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese.
639

Development of a Framework for Preliminary Risk Analysis in Transportation Projects

Guo, Wei 25 December 2004 (has links)
"Over the years, risk analysis methodologies have been developed and implemented by many industries. NASA has implemented a cost efficient Continuous Risk Analysis methodology with good results. The U. S. Department of Transportation also states that a continuous risk analysis is the key in identifying, addressing, and handling risks before they become threats to success. However, current practices seldom incorporate this concept into real transportation projects. In general, risk is simply disregarded in feasibility studies. One of primary reasons is the lack of a feasible and effective risk analysis approach to guide efficient implementation in real projects. This thesis reviews current risk analysis practices used in public transportation projects. Using a case study, it also explores potential obstacles encountered in the implementation of systematic risk analysis. Finally, this thesis presents a preliminary risk analysis framework developed through the case study and enriched subsequently by incorporating material documented in the literature. The proposed risk analysis approach is to help achieve continuous risk analysis in transportation projects by enabling early start, frequent implementation, extensive application and flexible adoption."
640

Towards a better understanding of manual lifting injuries and assessment: a cognitive algorithms approach. / CUHK electronic theses & dissertations collection / Digital dissertation consortium

January 2002 (has links)
Yeung Sai Mo, Simon. / "June 2002." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (p. 255-278). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

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