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A Bayesian Approach to Detect the Onset of Activity Limitation Among Adults in NHISBai, Yan 06 May 2005 (has links)
Data from the 1995 National Health Interview Survey (NHIS) indicate that, due to chronic conditions, the onset of activity limitation typically occurs between age 40-70 years (i.e., the proportion of young adults with activity limitation is small and roughly constant with age and then it starts to change, roughly increasing). We use a Bayesian hierarchical model to detect the change point of a positive activity limitation status (ALS) across twelve domains based on race, gender, and education. We have two types of data: weighted and unweighted. We obtain weighted binomial counts using a regression analysis with the sample weights. Given the proportion of individuals in the population with positive ALS, we assume that the number of individuals with positive ALS at each age group has a binomial probability mass function. The proportions across age are different, and have the same beta distribution up to the change point (unknown), and the proportions after the change point have a different beta distribution. We consider two different analyses. The first considers each domain individually in its own model and the second considers the twelve domains simultaneously in a single model to“borrow strength" as in small area estimation. It is reasonable to assume that each domain has its own onset.In the first analysis, we use the Gibbs sampler to fit the model, and a computation of the marginal likelihoods, using an output analysis from the Gibbs sampler, provides the posterior distribution of the change point. We note that a reversible jump sampler fails in this analysis because it tends to get stuck either age 40 or age 70. In the second analysis, we use the Gibbs sampler to fit only the joint posterior distribution of the twelve change points. This is a difficult problem because the joint density requires the numerical computation of a triple integral at each iteration. The other parameters of the process are obtained using data augmentation by a Metropolis sampler and a Rao-Blackwellization. We found that overall the age of onset is about 50 to 60 years.
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Étude de l'applicabilité des POCIS (Polar Organic Chemical Integrative Sampler) au dosage des résidus de médicaments dans les effluents hospitaliers / Study of the applicability of POCIS (Polar Organic Chemical Integrative Sampler) for monitoring pharmaceuticals in hospital wastewaterBailly, Emilie 08 April 2013 (has links)
L’évaluation des risques environnementaux et sanitaires liés à la présence de résidus de médicaments dans l’environnement, représente un enjeu majeur en particulier au regard de la gestion du cycle des usages de l’eau. Les effluents des établissements de soins représentent une source non négligeable de pollution et justifient le développement de techniques spécifiques de mesures des émissions de résidus de médicaments dans leurs eaux usées. Dans le cadre de ces développements de méthode, l'échantillonnage représente une des difficultés majeures car la matrice brute des eaux en sortie des hôpitaux est très chargée en matières organiques, les débits sont extrêmement variables, les sites de prélèvement sont difficiles d'accès et il existe une forte variabilité des dispensations des traitements jour/nuit et semaine/week-ends. Les échantillonneurs intégratifs apparus récemment, offrent une alternative intéressante aux stratégies d’échantillonnage existantes, permettant d'effectuer un suivi moyenné sur de longues périodes d'observation associé à une simplicité d'usage et une réduction des coûts. Ce travail porte sur l’étude de l’applicabilité des échantillonneurs intégratifs POCIS (Polar Organic Chemical Integrative Sampler) au dosage des résidus de médicaments dans les effluents hospitaliers. Ce dispositif a principalement été utilisé dans les eaux de surface et les effluents de STEP et son application dans les eaux usées reste rare. 6 molécules déjà identifiées comme représentatives des grandes familles de médicaments utilisés à l'hôpital (Aténolol, Prednisolone, Méthylprednisolone, Sulfaméthoxazole, Ofloxacine, Kétoprofène) ont été retenues.Les cinétiques d’adsorption des molécules sur les POCIS ont été suivies en laboratoire en condition de maitrise des paramètres les plus influents : température, vitesse de l’eau, charge en matière organique, colmatage…Ce calibrage a pour but de déterminer le coefficient d’échantillonnage Rs (L/j) spécifique à chaque molécule et nécessaire au calcul de la concentration dans le milieu d’exposition du POCIS. Nous avons observé une augmentation des Rs quand la vitesse de l'eau augmente ou quand la température augmente. Dans les eaux usées, la valeur de Rs est plus faible et la durée de la phase linéaire est réduite comparée à l'eau du robinet. Pour ce type d'application, la période d'exposition ne devra pas dépasser 4 à 5 jours en raison du colmatage des membranes et d'une teneur élevée en particules organiques dissoutes. Après calibrage dans l’eau du robinet et dans l’eau usée, les POCIS ont été exposés in situ dans un effluent hospitalier pour mesurer les concentrations en 6 molécules ciblées. Cinq ont pu être quantifiées et les concentrations calculées à partir des extraits des POCIS sont concordantes avec celles obtenues par prélèvement direct d’un échantillon moyenné d’eaux usées. Le facteur limitant réside dans les difficultés d’accès au site et la présence de solides dans le collecteur d'eaux usées. Ce travail ouvre des perspectives quant à l'application des POCIS pour les effluents hospitaliers et pourra à terme contribuer à l'acquisition de données pour une meilleure surveillance des rejets. / The assessment of the environmental and public health risks due to pharmaceutical residues, is a main issue particularly in the light of water cycle management and water resources. Hospitals are supposed to be a main source of pollution and the assessment of their contribution to the overall pharmaceutical pollution is necessary. Monitoring the pharmaceutical loads in hospital sewage is a great challenge because of the difficulties which have to be overcome to obtain representative samples: high organic content and suspended solids, wastewater flow variations, difficult access to sampling sites, variations of pharmaceutical release throughout the day resulting from hospital activities. An interesting alternative way is to use passive samplers, which allow for the measurement of Time Weighted Average (TWA) concentrations, overcoming many shortcomings of the spot sampling techniques. The aim of this work is to evaluate the applicability of POCIS for the monitoring of pharmaceuticals in hospital wastewater. This tool is mainly used for surface water or WWTP effluent and its application for wastewater sampling remains scarce. This study was conducted on six compounds already selected as representative of some of the main class of pharmaceuticals used at the hospital (Atenolol, Prednisolone, Methylprednisolone, Sulfamethoxazole, Ofloxacin, Ketoprofen). POCIS were calibrated for the analytes of interest in tap water and wastewater in laboratory conditions close to relevant environmental conditions (temperature, flow velocity, fouling). Sampling rates (Rs) were determined and we observed a significant increase with flow velocity and temperature. Whatever the compound, the Rs value was lower in wastewater and the linear phase of uptake was shorter than in tap water. A five-day period was defined as the optimal duration for POCIS exposition in wastewater.POCIS were then deployed in a hospital sewage pipe during four days and the estimated water concentrations were close to those measured in twenty-four hour composite samples, carried out with an autosampler.This work gives encouraging results for the deployment of POCIS in wastewater that could be a useful tool for pharmaceutical pollution management.
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Adaptação do ensaio SPT para determinação de parâmetros adicionais para o dimensionamento de fundações / Adaptation of the SPT test for the determination of additional parameters for the design of foundationsMarlon Queiroz Ferreira 08 March 2016 (has links)
A presente pesquisa foi desenvolvida com o intuito de agregar alguns procedimentos ao Ensaio SPT, para se obter um maior número de parâmetros para o dimensionamento de fundações, visto que este ensaio é o tipo de investigação de subsolo mais utilizado no Brasil para este fim. Os procedimentos adicionados foram: medida de eficiência do equipamento e ensaio de arrancamento do amostrador em cada camada distinta de solo atravessado. Foram realizados nove ensaios de arrancamento do amostrador, em três furos de sondagem, nas profundidades de dois, cinco e dez metros (três camadas de solos distintas). Em um quarto furo foram realizadas duas provas de carga à compressão no amostrador (nas profundidades de dois e cinco metros) para determinação da eficiência do equipamento. Por meio destes ensaios foi possível obter: a resistência de ponta do ensaio SPT, a resistência por atrito lateral na face externa do amostrador, e a razão de atrito do ensaio SPT, que pode ser usada para a classificação de solo de modo similar ao utilizado para o ensaio de cone. Além destes resultados, neste trabalho foi também analisada a relação entre a resistência por atrito interna e externa no amostrador durante o ensaio, conhecida por a. Esta relação mostrou-se maior para a camada de solo com grande porcentagem de pedregulho e menor para a camada que apresentava maior porcentagem de argila. Foi observado também que o valor de a cresce linearmente com a razão entre o valor de NSPT e a tensão vertical efetiva na profundidade do ensaio. Os resultados deste trabalho também mostraram que o valor da razão entre a resistência de ponta do ensaio SPT (qSPT) e o valor de NSPT é único para o mesmo tipo de solo. Além disso, os valores encontrados nesta pesquisa da razão qSPT/ NSPT são próximos aos valores da razão entre a resistência de ponta do ensaio de cone e o NSPT encontrados na literatura. / This research was developed in order to add some procedures to the SPT test, to obtain new parameters for the design of foundations, since this test is the most used in Brazil for this purpose. The additional measurements are: the energy delivered to the rod during a hammer impact, and the sampler\'s shaft resistance known from static uplift. For this investigation, nine uplift tests were conducted on the SPT sampler, in three boreholes, at three different depths (two, five and ten meters) to the determination of the SPT side friction resistance. Additionally, two compressive static load tests were carried out on the sampler in a fourth borehole to the determination of the efficiency of the SPT equipment. The results showed that the SPT test could provide measurements of end bearing and side friction resistances. Also, a SPT normalized friction ratio was determined for the classification of soil in a similar way used based on CPT data. In addition, the ratio between the internal and the external skin friction in the sampler during the test, known as \"a\" was analyzed. The values of this ratio were higher for the soil with higher percentage of gravel, and smaller for the soil with higher percentage of fines. Additionally, the \"a\" value increases linearly with the ratio between the NSPT value and the effective vertical stress at the tested depth. The results of the ratio between the SPT end bearing resistance and the NSPT found in this research are of similar magnitude to the ratios between CPT end bearing resistance and the NSPT found in the literature.
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Bayesian Semiparametric Models For Nonignorable Missing Datamechanisms In Logistic RegressionOzturk, Olcay 01 May 2011 (has links) (PDF)
In this thesis, Bayesian semiparametric models for the missing data mechanisms of nonignorably missing covariates in logistic regression are developed. In the missing data literature, fully parametric approach is used to model the nonignorable missing data mechanisms. In that approach, a probit or a logit link of the conditional probability of the covariate being missing is modeled as a linear combination of all variables including the missing covariate itself. However, nonignorably missing covariates may not be linearly related with the probit (or logit) of this conditional probability. In our study, the relationship between the probit of the probability of the covariate being missing and the missing covariate itself is modeled by using a penalized spline regression based semiparametric approach. An efficient Markov chain Monte Carlo (MCMC) sampling algorithm to estimate the parameters is established. A WinBUGS code is constructed to sample from the full conditional posterior distributions of the parameters by using Gibbs sampling. Monte Carlo simulation experiments under different true missing data mechanisms are applied to compare the bias and efficiency properties of the resulting estimators with the ones from the fully parametric approach. These simulations show that estimators for logistic regression using semiparametric missing data models maintain better bias and efficiency properties than the ones using fully parametric missing data models when the true relationship between the missingness and the missing covariate has a nonlinear form. They are comparable when this relationship has a linear form.
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Measurements of ozone vertical distribution in a hinoki (Chamaecyparis obtusa) forest using a sensitive ozone passive samplerTAKENAKA, Chisato, 竹中, 千里, HIBINO, Michiko, 日比野, 道子, KURIYAMA, Haruyo, 栗山, 芳留代 12 1900 (has links) (PDF)
農林水産研究情報センターで作成したPDFファイルを使用している。
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A Novel Device and Nanoparticle-Based Approach for Improving Diagnosis and Treatment of pelvic Inflammatory DiseaseCover, Natasha Faith 01 January 2012 (has links)
Pelvic Inflammatory Disease (PID) is one of the most common causes of morbidity in women. PID is a polymicrobial infection of the female reproductive tract, and is associated with pelvic pain, abnormal uterine bleeding, and tubal damage that can lead to ectopic pregnancies and infertility. It is curable but the effects of PID can be permanent if not properly diagnosed and treated. PID presents as a spectrum of disease and is often missed at early stages; even acute PID can be difficult to diagnose, as there is no single conclusive diagnostic test. Currently, PID is identified and treated syndromically because pelvic pain is the only consistent clinical finding. The Center for Disease Control and Prevention (CDC) recommends doxycycline, a broad-spectrum antibiotic, for treatment but doxycycline can cause gastrointestinal irritation and local inflammation leading to an incomplete treatment. Most cases of PID are polymicrobial infections of the tubes and endometrium, which are not accessible to culture due to the difficulty of procuring samples above the naturally contaminated vagina and distal cervix. Given the difficulty of properly diagnosing PID and the limitations and side effects of the current treatments, there is an urgent need for new approaches for improving the accuracy for diagnosis and treatment of PID. We propose a new and practical approach to collect sterile specimen samples from the endometrium for more accurate PID diagnosis, and to treat the reproductive tract locally using doxycycline-loaded nanoparticles. The proposed research presents a novel sterile uterine sampler cover (SUSC) device that can safely and effectively collect uncontaminated specimen samples from the uterus, and also deliver nano-encapsulated drugs directly to the site of infection. The analysis of uncontaminated endometrium samples is expected to provide an understanding of uterine flora in symptomatic and asymptomatic women, and will lead to the identification of infective microbes in symptomatic women for pathogen-specific treatment. The use of nano-encapsulated doxycycline will enable localized drug delivery to lower drug dosage and minimize side effects for the patient. The doxycycline-loaded nanoparticles are characterized and evaluated based on their drug release properties, size distribution, and tissue response in vitro. This research will lead towards a more effective approach for the diagnosis and treatment of PID while freeing women from prolonged systemic treatments and their adverse effects. Moreover, this research will increase our understanding of the uterine biome under various hormonal and pathologic conditions, in symptomatic and asymptomatic women.
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Development and Application of a Flow-through Sampler for Semi-volatile Organic Compounds in AirXiao, Hang 18 March 2010 (has links)
The investigation of the atmospheric fate and transport of semi-volatile organic compounds (SOCs) often requires the sampling of large volumes of air (>100 m3) in a relatively short period of time. Conventionally high-volume pumps are not suitable for remote areas without access to reliable network power. We have developed a flow through sampler for such situations. It consists of a horizontally-oriented flow-tube, that can collect gaseous and particle-bound SOCs from large volumes of air by turning into the wind and having the wind blow through a porous sampling medium such as polyurethane foam. Through both indoor and outdoor experiments, we quantified its air sampling rate (through battery operated anemometers inside and outside of the flow tube), its sampling efficiency (by theoretical plate number analysis of the break-though curves for PCBs, PAHs, OCPs and PBDEs), and its accuracy (by comparison of concentrations, time trends, temperature dependences and isomer ratios with those obtained by conventional high-volume sampling) under conditions of constant and variable meteorological conditions (wind speed, temperature). The flow-through sampler was deployed to monitor SOC concentrations at a remote Chinese research station located close to Nam Co Lake, Tibet. During the campaign, fifteen 1 month-long samples were taken, corresponding to sample volumes between 5,000 and 20,000 m3. Despite those large sample volumes, only HCB and HCHs experienced break-through, but application of frontal chromatograph theory allows the estimation of breakthrough-corrected air concentrations even for those relatively volatile SOCs. The pesticide levels at Nam Co are generally very low. Most pesticides had higher levels during summer, resulting in a strong temperature dependence. This is correlated with air mass origin across the Himalayas in the Gangetic plains of India and Bangladesh. The flow through sampler constitutes a feasible method for reliably and quantitatively collecting SOCs from large air volumes.
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Samplers, videoclipes e letras: um debate sobre possibilidades de abordagem com músicas de rap na universidadePassold, Gabriel 16 February 2017 (has links)
Esta pesquisa tem por objetivo debater a abordagem de músicas de rap na universidade, analisando conceitos e princípios utilizados em alguns trabalhos que abordam os elementos das letras, imagens dos videoclipes e samplers, mais das vezes enquanto representação, assim como algumas das implicações desse procedimento, como a valorização das letras das músicas e o relevo dado ao papel do artista engajado para uma possível emancipação das ideologias da dominação, em detrimento de artistas e/ou obras não ajustadas a tais conceitos e princípios teórico-metodológicos. Por outro lado, em nossa abordagem das rimas, samplers e no caso dos videoclipes de música, das imagens, partimos do pressuposto de que a música não é necessariamente a representação de algo, mas antes, é formada por um tecido estético com múltiplas possibilidades interpretativas. Dessa forma, a pesquisa procura mostrar algumas consequências da interpretação do rap pela lógica representativa, como a constituição de uma espécie de senso comum fundamentando em algumas hierarquias sociológicas e políticas tomadas de antemão, assim como discutir sobre outras possibilidades de pensar a relação entre música, história e política, como por exemplo, por um senso comunitário traçado no interior das expressões estéticas. / This research aims to discuss the approach of rap music in the university, analyzing concepts and principles used in some works that deal with the elements of lyrics, images of video clips and samplers, more often as representation, as well as some of the implications of this procedure, such as the valorization of the lyrics of the songs and the importance given to the role of the artist engaged in a possible emancipation of the ideologies of domination, in detriment of artists and / or works not adjusted to such concepts and theoretical-methodological principles. On the other hand, in our approach on rhyming, samplers, and in the case of music video clips, the images, we start from the assumption that music is not necessarily the representation of something but rather is formed by an aesthetic fabric with multiple interpretative possibilities. In this way, the research attempts to show some consequences of the interpretation of rap by the representative logic, such as the constitution of a kind of common sense based on some sociological and political hierarchies taken beforehand, as well as discussing other possibilities of thinking about the relationship between music, history and politics, as for example, by a community sense traced within aesthetic expressions. / Dissertação (Mestrado)
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Effects of Agrochemicals on Riparian and Aquatic Primary Producers in an Agricultural WatershedDalton, Rebecca L. January 2014 (has links)
In agricultural watersheds, streams are intimately connected with croplands and may be inadvertently exposed to agrochemicals such as fertilizers and herbicides. Riparian plants and aquatic primary producers (aquatic plants, phytoplankton and periphyton) may be particularly affected by agrochemicals due to their taxonomic similarity to the intended targets (crop and weed species). The overall objective of this thesis was to assess the effects of fertilizers and the herbicide atrazine on riparian plants and aquatic primary producers. Effects were assessed across varying scales of observation ranging from empirical field studies at the watershed scale to in-situ experimental manipulations in two temperate streams to a laboratory concentration-response experiment.
Twenty-four stream/river sites located across the South Nation River watershed, Canada ranged in surrounding agricultural land use (6.7-97.4 % annual crops) and in-stream concentrations of reactive phosphate (4-102 μg/L) and nitrate (3-5404 μg/L). A gradient of atrazine contamination spanning two orders of magnitude (56 d time-weighted-average concentrations of 4-412 ng/L) was observed using polar organic chemical integrative samplers (POCIS). A total of 285 riparian and aquatic plant species were identified with species richness ranging from 43-107 species per site. Atrazine and the percentage of surrounding annual crops had no statistically significant effects on community structure. In contrast, an increase in the percentage of non-native species, a decrease in submerged macrophytes and a decrease in overall floristic quality was observed along a gradient of increasing nitrate. Similarly, periphyton biomass increased with increasing nitrate across the watershed and was associated with the Chlorophyta. In contrast, no clear response was observed in periphyton exposed to nutrient enrichment and atrazine contamination in in-situ periphytometer experiments in two streams. Greenhouse concentration-response experiments provided evidence that the sensitivity of duckweed (Lemna minor) to atrazine was lower in populations previously exposed to the herbicide. However, the overall range in biomass 25% inhibition concentrations was small (19-40 μg/L atrazine). A clear gradient in agrochemical contamination was observed at the watershed scale and this research provided evidence of negative effects on riparian and aquatic primary producers. Effects of nutrients, specifically nitrate, superseded observable effects of the herbicide atrazine.
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Contributiopn de l'approche effect directed analysis à l'identification de perturbateurs endocriniens dans les milieux aquatiques / Contribution of effect directed analysis approach to the identification of endocrine disrupting chemicals in aquatic systemsCreusot, Nicolas 06 December 2011 (has links)
L’objectif général de cette thèse concerne la mise en place et l’évaluation d’une approche de type effect directed analysis (EDA), couplant bioessais in vitro et analyses physico-chimiques, pour la caractérisation de la contamination des milieux aquatiques par les perturbateurs endocriniens (PE) et leur identification. De nouveaux outils in vitro ont été développés et intégrés à une approche multi-bioessais pour la détection de polluants émergents afin de permettre un large diagnostic de la contamination par les PE. Parmi eux, le bioessai basé sur le pregnane X receptor humain s’est avéré complémentaire des cibles classiquement étudiées (e.g. récepteurs des œstrogènes (ER), des androgènes (AR) ou des hydrocarbures aromatiques (AhR)). Combinés, ces bioessais ont permis de déterminer des profils intégrés de la contamination inédits dans le sédiment et les eaux de surface, mettant en lumière la nécessité de considérer d’autres cibles biologiques que ER et AhR et de s’intéresser à l’ensemble des compartiments du milieu aquatique pour une meilleure évaluation de la contamination. En particulier, l’utilisation combinée de ces nouveaux outils à des capteurs passifs de type POCIS (polar organic compound integrative sampler) s’est révélée pertinente pour évaluer la contamination de la colonne d’eau par des composés hydrosolubles. Enfin, une démarche EDA, intégrant ces bioessais et des méthodes physico-chimiques d’extraction et de fractionnement adaptées, a été validée pour l’identification des composés détectés. Son application sur deux sites soumis à des contaminations chimiques différentes (mixte urbaine/agricole et pharmaceutique) a permis d’évaluer la contribution des polluants cibles, dont les prioritaires, dans les réponses des bioessais et d’identifier de nouveaux PE. / The aim of this thesis was to develop and to evaluate an effect directed analysis (EDA) approach, combining in vitro bioassays and chemical analysis for the characterization of aquatic systems contamination by endocrine disrupting chemicals (EDCs) and their identification. For integrative contamination assessment, new in vitro tools have been developed and evaluated for the detection of emerging pollutants, and then integrated in a multi-bioassays approach. In particular, the human pregnane X receptor (PXR) based bioassay provided further information on bioactive contaminants and thereby enhanced the environmental diagnostic as regard to classical biological target (e.g. estrogen (ER), androgen (AR) or aryl hydrocarbon receptors (AhR)). Such multi-receptors approach allowed determining novel integrative toxicity profiles in sediment and surface water. Overall, our results demonstrated the need to integrate other biological target than ER and AhR, and to assess contamination partitioning for a better hazard/risk assessment. For such purpose, combined use of polar organic compound integrative sampler and in vitro bioassays provided suitable tools to assess active hydrosoluble chemicals in surface water. Finally, in order to identify the compounds responsible for the detected activities, the multi-receptors approach has been integrated in EDA strategy applied to two river sites under different chemical pressures (urban/agricultural and pharmaceutical). To tackle this challenge, extraction and fractionation methods were developed and evaluated in order to encompass a diversity of active chemicals that are detected by in vitro bioassays. The EDA approach allowed determining partial contribution of priority pollutants in biological responses as well as the identification of new EDCs.
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