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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.
181

Statistical methods to model the influence of age and gender on the behavioral risk factors of HIV/AIDS

Tlou, Boikhutso January 2010 (has links)
The effects of gender and age on the behavioral risk of HIV/AIDS are not clearly understood as previous distinct studies which have been carried out, have given disputable and contradictory outcomes. This study therefore, discusses the statistical methods which can be used to model the influence of age and gender on the behavioral risk factors of HIV/AIDS. In general, generalized linear models are the main methods which can be applied to depict the impact of age and gender on the behavioral risk of becoming infected with HIV/AIDS virus. In this study, the main methods used were logistic regression, log-linear regression and multiple regressions. Behavioral risk was taken as the dependent variable while age, gender, number of sexual partners, religious beliefs and alcohol and drug abuse were fitted as predictor variables. The three statistical methods gave significant results for gender and insignificant results for age. Furthermore, comparisons were made on the three regression methods and the logistic regression gave the best results. It was therefore concluded that gender plays a significant role on the behavioral risk of HIV/AIDS. The results of the study showed that gender of the student and number of sexual partners had a significant effect on the risk behavior of the university students. In future, it may be very important to find out why age is not a significant factor on risk behavior of HIV/AIDS among university students.
182

Les radionucléides et le plomb émis par une usine de fertilisants au Liban : Etude de leurs mobilités dans les sols et les plantes pour une évaluation du risque sanitaire. / Radionuclides and lead emitted by a fertilizer plant in Lebanon : Study of their mobility in soils and plants for a health risk assessment.

Saba, Dany 04 November 2019 (has links)
L'utilisation des engrais chimiques phosphatés, et les usines de fertilisants, ayant comme matière première la roche phosphate et rejetant du phosphogypse, contribuent à l’élévation des teneurs des radionucléides naturels et des éléments traces métalliques dans l’environnement. Ces contaminations risquent d’affecter l’écosystème et la santé humaine.Cette étude évalue l’impact sanitaire des radionucléides naturels émetteurs gamma des séries de désintégration de 238U, 232Th, de l’élément naturel radioactif 40K et du Pb, présents dans la matière première et les produits d’une usine de fertilisants au Liban.L’objectif principal est de caractériser la contamination diffuse de ces polluants dans une optique d’évaluation du risque sanitaire dans 9 sites résidentiels, non-cultivés autour de l’usine. Un focus est spécifiquement porté sur l’évaluation quantitative du risque sanitaire lié à la consommation de la plante sauvage Dittrichia viscosa et l’ingestion accidentelle de poussières de sol pour les habitants de la zone étudiée. La notion de bioaccessibilité du Pb des sols et des plantes est intégrée dans ces évaluations. Des extractions chimiques par EDTA et le Physiologically Based Extraction Test (PBET) ont été utilisés pour une estimation in vitro, des fractions disponibles et bioaccessibles du Pb. Ces dernières ont été intégrées dans les calculs des risques. Les risques radiologiques relatifs aux rayonnements ionisants gamma des radionucléides ont également été estimés via les paramètres radiologiques.L’ensemble des travaux a montré que l’usine de fertilisants engendre une contamination diffuse qui augmente les niveaux de radionucléides et du Pb dans l’environnement proche, plus précisément dans les sols (pour 238U, 226Ra et leurs descendants 214Pb, 212Pb et 210Pb, ainsi que pour Pb), et dans les parties aériennes des plantes Dittrichia viscosa (pour Pb et 210Pb). L’étude de la distribution du 210Pb et les fractions PbEDTA apportent des informations complémentaires pour caractériser l’apport en Pb dû à l’activité de l’usine. Les résultats ont montré que les valeurs moyennes des concentrations d’activité des radionucléides dans les échantillons de sol étaient légèrement supérieures à ceux déterminés dans d'autres régions libanaises et aux valeurs moyennes mondiales. D’après les paramètres radiologiques, aucun risque significatif n’a été identifié pour la population fréquentant la zone.Les concentrations en Pb pseudo-total de sol ont été inférieures aux seuils applicables. Des dépassements de seuil ont été constatés pour les teneurs en Pb dans les feuilles de Dittrichia viscosa.Deux schémas d’évaluation de risque sanitaire du Pb ont été étudiés : un premier schéma classique basé sur l’hypothèse de l’ingestion des teneurs totales en Pb dans les sols et les plantes ; un deuxième schéma où seulement les fractions pouvant atteindre la circulation systémique ont été évaluées et considérées dans les calculs de risque. Ces deux schémas ont été appliqués à deux scénarios de terrain à forte exposition. La prise en compte des concentrations de Pb bioaccessible dans les calculs réduit considérablement (au moins d’un facteur de 10) le risque potentiel pour les deux scénarios alors que les calculs du risque selon le schéma classique montrent un risque significatif pour les enfants. Quel que soit le schéma de calcul de risque retenu, l’ingestion des plantes reste la voie principale d’exposition pour les deux scénarios maximalistes. / The use of phosphate fertilizers and phosphate rock as raw material by fertilizer plants, and the by-product phosphogypsum, contribute in increasing the levels of natural radionuclides and trace metals in the environment. This may affect the ecosystem and human health.This study evaluates the radiological impact of natural gamma-emitting radionuclides, mainly 238U, 232Th and their decay product, and 40K. As well as, it evaluates the health impact of Pb, present in the raw material and fertilizers produced by a fertilizer plant in Lebanon.The main objective is to characterize the diffuse contamination of these pollutants with a view to assess the health risk in 9 non-cultivated residential sites around the plant. A focus on the quantitative assessment of the health risk is specifically linked to the consumption of the wild plant Dittrichia viscosa and the accidental ingestion of soil dust for the inhabitants of the study area. The concept of bioaccessibility of soil and plant Pb is integrated into these assessments. Chemical extractions using EDTA and the Physiologically Based Extraction Test (PBET) were used for in vitro estimation of available and bioaccessible Pb fractions. These were incorporated into the risk calculations. The radiological risks related to gamma ionizing radiation from radioelements were also estimated via radiological parameters.All of the work has shown that the fertilizer plant generates diffuse contamination that increases the levels of radionuclides and Pb in the near environment, specifically in soils (for 238U, 226Ra and their decay products 214Pb, 212Pb and 210Pb, as well as for Pb), and in the aerial parts of Dittrichia viscosa plants (for Pb and 210Pb). The study of the distribution of 210Pb and PbEDTA fractions provide additional information to characterize the Pb contribution due to the activity of the plant. The results showed that the mean values of activity concentrations of radioelements in soil samples were slightly higher than those determined in other Lebanese regions and worldwide average values. Based on the radiological parameters, no significant risk has been identified for the population frequenting the area.The pseudo-total soil Pb concentrations were below the applied thresholds. Threshold exceedances were observed for Pb levels in Dittrichia viscosa leaves.Two health risk assessment schemes for Pb were studied: a first classical scheme based on the hypothesis of the total ingestion of total Pb levels in soils and plants; a second scheme where only fractions reaching the systemic circulation have been measured and considered in risk calculations. These two schemes were studied for two high-exposure field scenarios. Taking into account the bioaccessible Pb concentrations in the calculations greatly reduces (at least by a factor of 10) the potential risk for both scenarios, whereas the classical risk calculations show a significant risk for the children. Whatever the chosen risk calculation scheme, ingestion of plants remains the main route of exposure for the two maximalist scenarios.
183

Determining and Evaluating Cost-Effective Food Safety Risk Reduction Strategies at Retail Meat Facilities

Lehrke, Linda January 2006 (has links)
In spite of the documented success of Pathogen Reduction and Hazard Analysis and Critical Control Points (PR/HACCP) at the processing level, farm-level and retail-level application is optional. Several factors impact the gap of food safety regulations from farm to fork. This thesis focuses on the retail level. At the retail level, pathogen survival and the associated ability to cause further disease to humans even after being subjected to certain processing and packaging conditions have varying implications on the probability of sickness or death. This issue also arises over the fact that, sometimes, appropriate handling and processing instructions are not properly followed by consumers. The primary goals of the project are to develop an optimal food safety intervention strategy that incorporates risk, cost, and the value of pathogen reduction with alternative control mechanism. We wish to evaluate incentives for PR/HACCP-like planning and adherence to best management practices that promote safe food production. These incentives will be evaluated for the retail level. In addition, we will develop optimal intervention strategies for ready-to-eat meats and poultry products that incorporate risk assessment, cost of intervention, and the value of risk reduction of alternative strategies for the farm-to-table continuum. The model adopted in this study is an expansion of the stochastic optimization model developed by Nganje, Kaitibie, and Sorin (2005) to include the optimal intervention strategy at the retail ( consumer) level. These components are simulated with firm-level microbial data at the processing and retail level using stochastic optimizer software. Stochastic dominance was also used to compare across the optimal strategies and determine if there is one clear choice that is preferred. This allowed us incorporate risk preferences of firms. The scenario method was used to determine what factors would likely affect the adoption of PR/HACCP at the retail level. Finally, this thesis provides firms and policymakers a direction for future options concerning risk mitigation strategies.
184

Participation, Information, Values, and Community Interests Within Health Impact Assessments

Iroz-Elardo, Nicole 05 June 2014 (has links)
Health impact assessment (HIA) has emerged in the U.S. as one promising process to increase social and environmental justice through addressing health equity issues within planning. HIA practice is guided by values such as democracy and equity and grounded in broad social determinants of health. The most readily applied definition of democracy is problematic because it implies an element of direct, participatory engagement with the public. This is at odds with HIA practice that largely relies on stakeholder engagement strategies. This dissertation critically examines the engagement strategies of three transportation planning HIA cases to more fully understand how the HIA process may or may not promote democratic values and protect community health interests. It employs a multi-case study design that uses qualitative content analysis to trace community health interests through the HIA process, HIA document, and target plan. It finds that while the field is overstating the participatory nature of HIA, commitments to health equity and broad determinants of health protect community health interests with and without robust engagement of community stakeholders.
185

Study of coliform bacteria in Canadian pulp and paper mill water systems : their ecology and utility as health hazard indicators

Gauthier, Francis. January 2000 (has links)
No description available.
186

"Prostitution", "risk", and "responsibility" : paradigms of AIDS prevention and women's identities in Thika, Kenya

Kielmann, Karina January 1993 (has links)
No description available.
187

Social Vulnerability and Bio-Emergency Planning: Identifying and Locating At-Risk Individuals

Richardson, Brian T 08 1900 (has links)
In 2006, the United States Congress passed the Pandemic All-Hazards Preparedness Act (PAHPA) which mandated that all emergency preparedness planning shall address at-risk populations. Further, in 2013, the reauthorization of this act, known as PAHPRA, defined at-risk individuals as "children, older adults, pregnant women, and individuals who may need additional response assistance." This vague definition leaves emergency managers, planners, and public health officials with the difficult task of understanding what it means to be at-risk. Further, once identified, the geographic location of at-risk individuals must be obtained. This research first uses the concept of social vulnerability to enhance the understanding of what it means to be "at-risk." Then, by comparing two data disaggregation techniques, areal weighted interpolation and dasymetric mapping, I demonstrate how error of estimation is affected by different scenarios of population distribution and service area overlap. The results extend an existing framework of vulnerability by stratifying factors into quantifiable and subjective types. Also, dasymetric mapping was shown to be a superior technique of data disaggregation compared to areal weighted interpolation. However, the difference in error estimates is low, 5 percent or less in 72 percent of the test cases. Only through local collaboration with community entities can emergency planners access the appropriate data to both: 1) understand the nature of at-risk individuals in their service areas and 2) spatially target resources needed to ensure all individuals are planned for in case of a bio-emergency.
188

Groundwater quality and human health risk assessment related to groundwater consumption in An Giang province, Viet Nam

Phan, Kim Anh, Nguyen, Thanh Giao 27 February 2019 (has links)
Groundwater is one of the main sources for water supply for domestic use, irrigation, aquaculture and industry in Mekong Delta. With rapidly increasing in human population, groundwater becomes more important for social and economic activities. This study evaluated the quality of groundwater using data from the eight monitoring wells over the period of 2009 - 2016. Human health risk was assessed for the population consuming groundwater contaminated with arsenic. The findings indicated that groundwater wells in An Giang province were contaminated with microorganisms. The total dissolved solids (TDS) and hardness in Phu Tan (PT) and Cho Moi (CM) wells were significant higher than the national technical regulations on groundwater quality (QCVN 09-MT:2015/BTNMT). In addition, groundwater wells in some small islands of An Giang were seriously contaminated with organic matters and arsenic. The mean arsenic concentration was up to 0.55 ± 1.21 mg/L. Estimation of carcinogenic risk for human population showed that the cancer risks ranged from medium (8.66 x 10-4) to high (8.26 x 10-2) for both children and adults. Alternative water supply sources should be offered for the population at risk. Besides, regular health check is essential for local people in the arsenic contaminated groundwater. / Nước ngầm là một trong những nguồn cung cấp nước chính cho sinh hoạt, tưới tiêu, nuôi trồng thủy sản và công nghiệp ở Đồng bằng sông Cửu Long. Cùng với sự gia tăng dân số, nước ngầm ngày càng đóng vai trò quan trọng hơn trong các hoạt động phát triển kinh tế - xã hội. Nghiên cứu đã tiến hành đánh giá diễn biến chất lượng nước ngầm thông qua số liệu của tám giếng quan trắc trong giai đoạn từ năm 2009 – 2016. Kết hợp với đánh giá rủi ro sức khỏe của người dân khi sử dụng nước ngầm chứa arsenic. Kết quả nghiên cứu cho thấy các giếng nước ngầm ở tỉnh An Giang đã bị nhiễm vi sinh. Tổng chất rắn hòa tan (TDS) và độ cứng ở trạm Phú Tân và Chợ Mới phân tích được cao hơn quy chuẩn cho phép (QCVN 09-MT:2015/BTNMT). Các giếng nước ngầm ở một số khu vực cù lao của tỉnh An Giang đã bị ô nhiễm hữu cơ và arsenic nghiêm trọng. Nồng độ arsenic trong nước ngầm có thể dao động lên đến 0.55 ± 1.21 mg/L. Rủi ro ung thư ở hai đối tượng người lớn và trẻ em khi sử dụng nước ngầm nhiễm arsenic dao động từ trung bình (8 người trong 1.000 người) tới cao (8 người trong 100 người). Cung cấp nguồn nước thay thế là giải pháp khả thi để giảm rủi ro sức khỏe cho con người trong trường hợp này. Ngoài ra, người dân địa phương cần được khám sức khỏe thường xuyên để kịp thời phát hiện và sớm điều trị bệnh.
189

[en] DETERMINATION OF POTENTIALLY TOXIC ELEMENTS IN HAIR DYES AND HEALTH RISK ASSESSMENT / [pt] DETERMINAÇÃO DE ELEMENTOS POTENCIALMENTE TÓXICOS EM TINTAS DE CABELO E AVALIAÇÃO DE RISCO À SAÚDE

JESSICA SOARES DOS SANTOS LIRA 29 April 2024 (has links)
[pt] Tinturas de cabelo, amplamente utilizadas em cosméticos, demandam atenção especial para garantir a ausência de substâncias prejudiciais à saúde. A Agência Nacional de Vigilância Sanitária (ANVISA) estabelece limites de impurezas, como 20 mg kg(-1) para Pb e 100 mg kg(-1) para a soma dos demais elementos potencialmente tóxicos. A fim de avaliar a ocorrência de elementos potencialmente tóxicos em tinturas comercializadas no Brasil, a espectrometria de massa com plasma indutivamente acoplado (ICP-MS) foi empregada neste estudo para determinar as concentrações de Al, Ba, Be, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, Pb, Sb, Sn, Sr, Ti e Zn em 26 amostras de tinturas de cabelo. A maioria das amostras apresentou baixas concentrações dos elementos estudados (< 1 mg kg(-1) ), exceto Pb em duas amostras (T01 e T09), tinturas à base de acetato de chumbo, que apresentaram concentrações de até 3.500 mg kg(-1) , e Al com concentrações de até 480 mg kg(-1) para a amostra H01. Utilizando metodologia do Scientific Committee on Consumer Safety da União Europeia, foram avaliados os riscos à saúde associados à exposição prolongada a esses elementos. Alguns elementos demonstram margens de segurança (MS) maiores do que 100, indicando exposição segura de acordo com a Environment Protection Agency (EPA). No entanto, Al, Pb, Cr, Mn e Ni apresentaram valores de MS abaixo de 100, suscitando preocupações em relação ao uso prolongado de algumas tinturas comerciais por apresentarem um valor de MS considerado inseguro (MS < 100) pela EPA. / [en] Hair dyes, widely used in cosmetics, require special attention to ensure the absence of harmful substances to health. The Agência Nacional de Vigilância Sanitária (ANVISA) establishes limits for impurities, such as 20 mg kg(-1) for Pb and 100 mg kg(-1) for the sum of other potentially toxic elements. In order to assess the occurrence of potentially toxic elements in hair dyes marketed in Brazil, inductively coupled plasma mass spectrometry (ICP-MS) was employed in this study to determine the concentrations of Al, Ba, Be, Cd, Co, Cr, Cu, Fe, Hg, Li, Mn, Mo, Ni, Pb, Sb, Sn, Sr, Ti, and Zn in 26 hair dye samples. Most samples showed low concentrations of the studied elements (< 1 mg kg(-1) ), except for Pb in two samples (T01 and T09), lead acetate-based dyes, which showed concentrations of up to 3,500 mg kg(-1) , and Al with concentrations of up to 480 mg kg(-1) for sample H01. Using the methodology of the Scientific Committee on Consumer Safety of the European Union, health risks associated with prolonged exposure to these elements were assessed. Some elements demonstrate margin of safety (MS) greater than 100, indicating safe exposure according to the Environmental Protection Agency (EPA). However, Al, Pb, Cr, Mn, and Ni showed MS values below 100, raising concerns regarding the prolonged use of some commercial dyes as they present a MS value considered unsafe (MS < 100) by the EPA.
190

Homeowner perception and response to radon

Himes, Lori J. 31 January 2009 (has links)
The Environmental Protection Agency estimates that numerous lung cancer deaths result every year due to radon exposure. Given this, radon education has become an important issue. The purpose of this research was to examine what action consumers had taken to respond to radon as a hazard following an education testing program and why they had taken that action. In the Fall of 1992, the Virginia citizens Consumer Council, in partnership with Virginia Cooperative Extension, conducted a radon education campaign to promote and sell radon test kits. This study is based on a follow-up telephone survey in which 100 Virginia consumers whose homes tested with high radon levels were asked what action they had taken to reduce their radon exposure. Using a proportional allocation, a sample was drawn from eight Virginia counties. statistical analysis included the use of cross tabulation tables and testing for association through the use of the gamma function. Statistically significant findings included: 1) objective risk does have an impact of hazard response; and 2) a correlation was found between how worried consumers were about their radon problem and their response to the hazard. / Master of Science

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