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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.
121

Resíduos de praguicidas em amostras de ovo comercializadas na cidade de São Paulo / Pesticide residue in egg samples commercialized in Sao Paulo City

Ciscato, Cláudia Helena Pastor 12 December 2008 (has links)
O uso de praguicidas na agricultura e pecuária pode acarretar sérios problemas à saúde dos seres humanos e dos animais. O controle da presença destas substâncias nos alimentos e no meio ambiente são um instrumento importante para minimizar o risco da exposição a estas substâncias. No Brasil, as informações sobre resíduos de praguicidas são insuficientes, especialmente quando se trata de produtos de origem animal. Um importante nutriente na dieta dos seres humanos é o ovo, principalmente na dieta infantil. De acordo com a FAO o Brasil ocupa o 7° lugar na produção de ovos com 1,72 milhões de dúzias por ano e um consumo per capita de 1,7 kg/ano (IBGE, 2003). Embora o consumo de ovos no Brasil seja um aspecto importante a maior parte da produção é exportada para outros países, principalmente, Arábia Saudita, China, Japão e Holanda. Este estudo foi desenvolvido no período de Janeiro de 2004 a Dezembro de 2006, um total de 150 amostras de ovos foram coletadas no mercado e avaliadas para a presença de resíduos de praguicidas organoclorados, organofosforados e piretróides. O método utilizado nas analises para determinar os resíduos de praguicidas nas amostras foi o DFG S19. Este método consiste em extração com solvente orgânico, etapa de partição com diclorometano e purificação com o emprego de cromatografia de permeação a gel e mini-coluna de sílica gel. Para a identificação e quantificação foi utilizada a metodologia analítica de cromatografia gasosa com detectores de captura de elétrons, nitrogênio/fósforo e fotométrico de chama. Os estudos de recuperação estiveram dentro da faixa de 70 a 120%. Os resultados das analises mostraram que o herbicida alacloro foi detectado em 0,7% das amostras analisadas e a sua contribuição para a ingestão diária crônica foi avaliada. Este praguicida não possui LMR em ovo, assim como o parâmetro de ingestão diária aceitável não foi estabelecido, porém a presença em ovo pode ser atribuída a alimentação dos animais e este praguicida devido a presença de cloro na molécula pode contribuir para o risco crônico à saúde humana. Embora apenas uma amostra tenha tido um resultado positivo, o controle dos alimentos destinados a população são um importante fator a ser controlado para garantir a saúde da população. / The use of pesticides in agriculture and livestock can cause serious problem for human beings and animal health. The control of these substances in food and in the environment is an important instrument to minimize these risks. In Brazil information about pesticide residues on food are insufficient, especially for animal products. An important nutrient supply on human diet is the egg, it provides several nutrients especially for children. According to FAO Brazil is the 7th in world ranking production and produces 1.72million dozen/year and the consumption is around 1.7 kg/year (IBGE, 2003). Despite of the Brazilian scene the consumption per capita almost of egg production is exported to other countries and the main countries are Saudi Arabia, China, Japan and Netherlands. The study was developed from January 2004 to 2006, 150 egg samples were collected from the national market and evaluated for pesticide residues of organochlorine, organophosphorus and pyrethroids pesticides. A multiresidue method were employed to determinate the pesticide in samples. The method uses an organic solvent extraction, a partition with dichloromethane and purification step by gel permeation chromatography (GPC) and silica gel column. For identification and quantification it was used gas chromatography techinique with ECD, NPD and FPD detectors. The recoveries for the method were within 70 to 120%. The results of the analysis showed that the herbicide alachlor were detected in 0.7% of the samples and the chronic dietary intake was evaluated. The pesticide does not have a proper use in egg, no MRL established and no ADI parameter. The presence could be attributed to feed contamination and the contribution to health risk could be detached once it has a chlorine molecule which could contribute to chronic diseases. Although only one sample was positive to pesticide residues this result is important to food quality control and consumer health. It helps to emphasize the risk studies on pesticide residues on animal and vegetable food.
122

Risk Assessment of Total Mercury and Methylmercury in Aquatic Products from Offshore Farms in China

Zhang, Wei, Zhang, Xue, Tian, Yuling, Zhu, Yan, Tong, Yindong, Li, Ying, Wang, Xuejun 15 July 2018 (has links)
Contamination of methylmercury (MeHg) in aquatic products has been a wide spread health concern. The objective of this study is to determine total mercury (THg) and MeHg concentrations in different species of aquatic products from major offshore farms in China, and to assess health impacts from consumption. Results showed that the concentrations of THg and MeHg ranged 5.6–328.4 ng/g (wet weight) and 4.3–303.6 ng/g (wet weight) in aquatic products, respectively, and were very variable among species and origin sources. Target hazard quotient (THQ) suggested that MeHg exposure via consumption posed high health risks to children aged 2–7 and higher income families. Residents above the age of 13 and with low income have relatively lower health risk of MeHg exposure. Health impacts on heart attacks and newborns’ IQ from MeHg exposure were evaluated using dose-response relationships. Results showed that mother’s consumption of aquatic products (at 6 ounce per day) may cause a loss of 0.38 IQ points for newborns. For non-pregnant, consumption of aquatic products may cause an increase rate of mortality and morbidity of heart attacks at 10.59 and 78.45 per 100,000 persons, respectively. The negative health impact of consuming seawater fish was higher than freshwater fish.
123

A Study of Rural Middle School Student Health Risk Behaviors Four County Reports

Schetzina, Karen E., Wilder, Regina, Nichols, Amelia 01 January 2007 (has links)
No description available.
124

The knowledge and practices of mercury coated bulbs disposal among households at ga-Mokgwathi village, Limpopo Province, South Africa

Mokhasi, Lucky January 2014 (has links)
Thesis ( MPH.) --University of Limpopo, 2014 / The purpose of this study was to investigate the knowledge and practices among households at Ga-Mokgwathi Village regarding the disposal of mercury coated bulbs. Cross-sectional design with quantitative approach was used in this study. The study objectives were to determine the knowledge about the disposal methods of mercury coated bulbs and also to determine the practices of handling broken mercury coated bulbs among the villagers of Ga-Mokgwathi. Data collection was done using self-administered questionnaires. Cluster random sampling was used in the study where a total number of 338 households were randomly selected to participate in the study. The results indicated that 36.7 % of the households at Ga-Mokgwathi Village had knowledge of safe disposal methods of mercury coated bulbs, 7.7% were not sure and 55.6% did not have such knowledge. Furthermore, the results indicated that 51.5% of the households had improper practices regarding the handling of broken mercury coated bulbs, 6.2% were not sure and 42.3% had proper practices regarding the handling of broken mercury coated bulb. The results of the study concluded that the majority of people were lacking knowledge of proper disposal methods and the handling of mercury coated bulbs. These results necessitate education of people about the disposal methods and handling of mercury coated bulbs.
125

Risk Factors for Emerging and Reemerging Infectious Diseases in Children

Murray, Meghan T. January 2019 (has links)
This dissertation assesses the factors that lead to the emergence of infectious diseases in children, particularly the emergence of multidrug-resistant organisms (MDROs) and diarrheal pathogens in vulnerable pediatric populations. It includes three manuscripts. The initial study is a systematic review that summarized the role of antibiotic exposure on the acquisition of MDROs in children. Twenty-nine studies met the inclusion criteria and a positive association between prior antibiotic use and subsequent colonization or infection with an MDRO was identified in most studies. There were wide variations among study sites, populations, and definitions of antibiotic use and MDROs. Therefore, limited inferences could be made on which components of antibiotic exposure have the greatest impact on MDRO development. The second analysis examines the relationship between prior stay at a pediatric long-term care (LTC) facility and infection with an MDRO among hospitalized children. This study included 2,945 infections in 258,664 pediatric admissions from 2006 through 2016. At least 1 MDRO was identified in 10% of infections. Of the 1,198 children who had previously resided in a pediatric LTC facility, only 1 child (0.08%) had an MDRO infection. However, prior receipt of pediatric LTC was associated with an increased likelihood of infection (OR 2.4, CI95 1.66 – 3.43), C. difficile infection (OR 2.57, CI95 1.26 – 5.25), days of antibiotic use (OR 1.01, CI95 1.01 – 1.02), length of stay (OR 1.01, CI95 1.01 – 1.01), and death (OR 4.38, CI95 2.93 – 6.55). The concluding study evaluates the association between animals living in or near the home and diarrheal disease in children. This research is a secondary analysis of the Global Enteric Multicenter Study case control study, which investigated the epidemiology of diarrheal illness in children <5 in sub-Saharan Africa and south Asia. Of 9,439 cases and 13,128 controls, 87% had ≥1 animal in their home. In a multivariable analysis adjusting for exclusive breastfeeding, water source, sanitation facility, number of children <5 years in the household, and wealth index, any animal on a child’s compound decreased the odds of diarrhea by 33% (aOR 0.66, CI95 0.59 – 0.74). However, children with diarrhea who had an animal present were not more likely to have a positive stool culture. Overall, the three studies provide a thorough analysis of several factors associated with the infectious disease emergence in children, particularly as related to MDROs and diarrheal disease. Environmental characteristics, including antibiotic use and interaction with animals, were shown to be important factors for emergent infectious disease across diverse settings. The development of pediatric infection prevention interventions should take into consideration environmental risk factors in order to effectively mitigate the risks posed infectious disease emergence.
126

Decision Analysis Considering Welfare Impacts in Water Resources Using the Benefit Transfer Approach

Shaqadan, Ashraf 01 May 2008 (has links)
Decision making in environmental management is faced with uncertainties associated with related environmental variables and processes. Decision makers are inclined to use resources to acquire better information in one or more uncertain variable(s). Typically, with limited resources available, characterizing the feasibility of such investment is desirable yet complicated. In the context of reducing inherent uncertainty, decision makers need to tackle two difficult questions, first, the optimal selection of variable(s) and second, the optimal level of information collection which produces maximum gain in benefits. We develop a new framework to assess the socioeconomic value of potential decisions of collecting additional information for given variable(s) to reduce inherent uncertainty. The suggested framework employs advanced social welfare concepts to facilitate eliciting the social acceptability of decisions to collect better information. The framework produces estimates of changes in utility levels and willingness to pay for target population using the benefit transfer method. The practicality of the framework is established using the following common problems in the field of water resources: 1) the uncertainty in exposure to health risk due to drinking a groundwater source contaminated with a carcinogen, 2) the uncertainty in non point source pollution loadings due to unknown hydrologic processes variability, and 3) the equity level in allocating mitigation responsibilities among polluters. For the three applications, the social acceptability of potential decisions is expressed in monetary terms which represent an extension on typical cost benefit analysis by including the socioeconomic value of a decision. The specific contribution of this research is a theoretical framework for a detailed preliminary analysis to transform and represent the given problem in useable terms for the social welfare analysis. The practical framework is attractive because it avoids the need to employ prohibitively expensive survey-based contingent valuation methods. Instead, the framework utilizes benefit transfer method, which imposes a theoretical behavioral structure on population characteristics such as age and income and to produce empirical estimates for a new problem setting.
127

Construction of Smoking-Relevant Risk Perceptions among College Students: The Influence of Need for Cognition and Message Content

Irvin, Jennifer Elaine 23 May 2003 (has links)
The primary purpose of this study was to examine the potential joint influence of need for cognition (NC), the dispositional preference for engaging in (or avoiding) effortful cognitive processing of information, and type of smoking risk message (i.e., factual and evaluative messages similar in message content and length) on the construction of smoking-relevant risk perceptions among college smokers. A secondary purpose was to examine potential mechanisms through which changes in risk perception might occur. 227 college smokers evaluated one of three pamphlets, (1) a factual (i.e., primarily fact-based) smoking risk pamphlet, (2) an evaluative (i.e., primarily emotion based) smoking risk pamphlet, or (3) a control pamphlet unrelated to smoking. Among occasional smokers, NC interacted with type of risk message to influence perceptions of post-pamphlet risk for several of the risk perception outcomes examined. Specifically, smokers lower in NC reported higher levels of perceived risk in response to the evaluative pamphlet whereas smokers higher in NC reported greater perceived risk in response to the factual pamphlet. The interaction did not predict risk perception outcomes among daily smokers. Significant changes in the mechanisms examined were not observed. Findings provide evidence that NC interacts with type of smoking risk message to influence changes in smoking-related health risk perceptions among occasional college smokers. Theoretical and practical implications are discussed.
128

Risk communication in familial cancer : the discursive management of uncertainty in genetic counselling

O'Doherty, Kieran Christian January 2005 (has links)
This thesis deals with the communication of cancer risk in genetic counselling sessions. There are two primary foci that form threads throughout both the theoretical and empirical chapters of the dissertation. The first concerns the meaning of risk as it manifests in familial cancer. In particular, there is a lack of a sound theoretical grounding for the probabilistic aspect of risk that is evident in many forms of risk communication. The thesis aims to illustrate the problem constituted by this lack of theoretical clarity. As most decisions faced by clients arise from attending genetic counselling, it is concluded that clients ' agency is highly constrained when genetic counselling is understood as a process of assisting decision - making. However, genetic counselling can be seen to enable agency when it is conceptualised as a process aimed at making available new medical technologies for the purpose of addressing clients ' own concerns. / Thesis (Ph.D.)--Faculty of Health Sciences, Dept. of Psychology, 2005.
129

A human health risk assessment of hazardous air pollutants in Portland, Oregon

Tam, Bonnie 03 February 2003 (has links)
In 1990, the Clean Air Act (CAA) Amendments authorized the regulation of 188 hazardous air pollutants (HAP). Exposure to HAPs at sufficient concentrations and durations can increase both cancer and serious adverse non-carcinogenic effects. The purpose of this study was to conduct a human health risk assessment using data of 43 HAPs from five monitor sites in Portland, Oregon during July 1999-August 2000. HAP concentrations were compared to carcinogenic and non-carcinogenic (health) benchmark concentrations; and emission sources were determined for HAPs that exceeded health benchmark concentrations. Additionally, cancer risks were determined for subpopulations and compared to cancer risks generated for the general population. Results of this study indicate that 20 HAPs exceeded carcinogenic benchmark concentrations (corresponding to a risk level of 1 x 10������) in at least one location. Chromium compounds posed the highest cancer risk (3.5 x 10������). Seventeen HAPs exceeded carcinogenic benchmark concentrations at all five sites. Seventy-five percent (%) of the total cumulative cancer risk was contributed by chromium compounds, 1,3-butadiene, formaldehyde and 1,1,2,2-tetrachloroethane. Three HAPs, chromium compounds, acrolein, and formaldehyde, exceeded non-carcinogenic hazard ratios of 1.0. Releases from area sources accounted for the largest percentage of HAPs that exceeded health benchmark concentrations. With respect to subpopulations, asthmatics teenagers (age 11-16) and asthmatic adults (age 18-50), had slightly elevated cancer risks of 1.4 x 10������ and 1.2 x 10������. respectively, compared to the general population risk level of 1 x 10������. Results of this study indicate that several HAPs pose a potential human health concern in Portland and that efforts should be made to reduce their emissions. Additional studies are warranted to further assess potential human health risks and the extent of HAPs in Portland, Oregon. / Graduation date: 2003
130

Development of a functional prototype of an environmental risk assessment parameter database on the World-Wide Web

Potter, Nathan Kent 06 August 1997 (has links)
The goal of the project was to develop a functional prototype of an environmental risk assessment parameter database on the World-Wide Web. The ability to develop a consolidated environmental database has become possible due to the phenomenal growth of the Internet and the World-Wide Web over the past few years. A large number of environmental resources do currently exist; however, with the large volume of information available, access, management, reliability, and retrievability have become increasingly difficult. To illustrate the prototype database, a practical environmental concern and the tools necessary to evaluate and characterize that concern were needed. Uranium (�������U) daughters leaching from abandoned mill tailing piles at three abandoned uranium mines in southwestern Colorado were chosen to demonstrate the database concept. The RESRAD environmental pathway modeling code served as the evaluation and characterization tool. Due to the size and complexity of RESRAD, a single radionuclide release rate equation was isolated as a controllable component of the code. The equation was a small part of the water pathway factor and examined the rate at which radionuclides absorbed in soil were leached by infiltrating water. This serves as the source term for groundwater contamination and directly applies to the �������U progeny leaching from mill tailing piles scenario. Parameters selected from the equation dealt with the background data that directly influenced the mobility of contaminates in the environment. Environmental data for the three Colorado sites were gathered and interpreted. Probability Density Functions (PDFs) were developed for input parameters and the results were then incorporated into the web site. / Graduation date: 1998

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