In an effort to apply Cumulative Risk Assessment (CRA) as developed by the U.S. EPA, the present study investigates the cumulative risks to Eastern oysters due to multiple stressors such as salinity, temperature and oxygen and carbon dioxide. I also compared the effectiveness of the Hazard Quotient Method (HQ) in CRA. Ambient conditions in the James River, VA were obtained from the Virginia DEQ database and respiratory responses were estimated using values from the literature. The multiple environmental stresses are evaluated using a probabilistic analysis that combines the environmental conditions. It was concluded that salinity was the most influential stressor in the model. Other risks were identified contributing to the vulnerability of the oysters. Crystal Ball simulations yielded that the oxygen uptake of oysters reduced by more than 29%. The HQ method was found to be inappropriate in analyzing cumulative risks for CRA. Oyster populations are dramatically declining in the James River and the Chesapeake Bay. Hence, effective oyster restoration activities are underway to rebuild oyster populations in the James River and throughout the Bay area.

Thesis advisor: Eric Dearing / Emerging research in developmental psychology and neuroscience suggests that childhood poverty is associated with high levels of exposure to multiple contextual risks, which cumulatively lead to persistent elevated stress levels that have a direct, as well an indirect (e.g., through parental processes), impact on child cognitive, academic, and socioemotional functioning (Evans & Kim, 2013). Such research has begun to change the way that scholars and practitioners envision the context of poverty, the persistence of the income-achievement gap, and the types of interventions that may be most effective in addressing disparities in children’s long-term educational success. However, research on the relations between poverty-associated stress and child outcomes is still in its infancy and many questions remain. In particular, it is unclear whether changing family economic circumstances matter, a question of concern for developmental science and public policy. Moreover, there is little work on moderators of relations between income, stress, and child outcomes, which could help identify factors that buffer children from the harm of stressful home environments. With longitudinal data from the Panel Study of Income Dynamics’ Child Development Supplement, the present study used fixed effects models to examine within-child associations between changes in family income, cumulative risk exposure (as measured by an index that includes a range of poverty-related stressors, such as economic strain, neighborhood crime, and physical and psychological home environments), and children’s cognitive, academic and socioemotional functioning. In addition, moderators of these associations were investigated in order to identify potential protective mechanisms and crucial levers for interventions and policy development. On the whole, findings were consistent with the cumulative stress model. On average, the estimated direct effects of changes in family income (i.e., prior to examining mediation or moderators) were not significant for changes in child outcomes. Yet, changes in income were, for the sample as a whole, indirectly related via changes in cumulative risk exposure: increases in income predicted decreases in cumulative risk exposure which, in turn, predicted improvements in achievement and declines in externalizing behavior. Additionally, these relations were moderated by child age, initial level of family income, and initial level of cumulative risk. / Thesis (PhD) — Boston College, 2017. / Submitted to: Boston College. Lynch School of Education. / Discipline: Counseling, Developmental and Educational Psychology.

With the growing number of children who receive a diagnosis of Autism Spectrum Disorder (ASD), there is an increasing need to identify risk markers that will allow for earlier diagnosis of this disorder. Since no single atypical behavior has been found that is shared by all 12-month-old infants who are later diagnosed with ASD, it is likely that a constellation of markers combine in a way that is more predictive of outcome at this age. Establishing a Cumulative Risk Index (CRI) is one way to investigate which combination of early risk markers is most predictive of later ASD diagnostic outcome. Temperament is one construct of behavior that could act as an early risk marker for ASD and therefore, could add predictive power to a CRI for this disorder. Temperament is defined as a "behavioral style" that includes individual differences in reactivity and self-regulation and emphasizes emotional, attentional and activity related characteristics. Another important aspect of temperament is that it exerts bidirectional influences upon the social environment. Therefore, the study of temperament could provide a method for understanding how children with ASD influence and are influenced by the environment of a testing session. Though important information has been collected about early temperament in children with ASD, much of the data is limited due to its dependence on retrospective and parent-report measures. One measure that allows for direct assessment of temperament during a controlled testing session is the Infant Behavior Record (IBR). The purpose of this study is to investigate early temperament in ASD by using the IBR as an assessment of temperament behaviors in high-risk 12-month old infants. Through this, we hope to reveal group differences in IBR scores, establish a relationship between temperament scores and cognitive test performance, and increase predictive value of the CRI when IBR scores are included. For this study, a revised version of the IBR was filled out while watching video record of the administration of the Mullen Scales of Early Learning (MSEL) at an infant's 12-month lab visit. Scores for the IBR reflected the examiner's impressions of the infant's orientation to objects and people and emotional state. Through using the IBR to study task orientation (TO), affect/extraversion (AE) and activity level (AL) in high-risk infants, this study found that only decreased AE behaviors distinguished high-risk infants who went on to develop ASD (HRA+ASD) from high-risk infants who did not receive an ASD diagnosis (HRA-ASD) (p=.08). To determine the relationship of temperament and cognitive assessment performance, IBR scores were compared to MSEL scores. This study found that across all participants, TO and AE behaviors were positively correlated with MSEL scores (AE rs=.27, p<.001; TO rs=.37, p<.001). This relationship remained true for both the high-risk (AE rs=.20, p<.001; TO rs=.23, p<.001) and the low risk groups (AE rs=.32, p<.001; TO rs=.54, p<.001), as well as for the HRA-ASD infants (AE, trend, p=.057; rs=.24, p<.001; TO rs=.459, p<.001), and the low-risk infants who did not go on to receive a diagnosis of ASD (AE rs=.35, p<.001; TO rs=.47, p<.001). The only group in this study that was found to have no correlations between temperament scores and MSEL scores was HRA+ASD. Since only AE behaviors distinguished HRA+ASD infants, this was the only IBR factor added to a pilot model of the CRI. This study found that the inclusion of AE to a pilot model of the CRI did not add significant predictive value to the model (p=.15). Through using the IBR to investigate temperament in HRA infants, the findings of this study suggest that there are some important differences in temperament behaviors for HRA+ASD infants. Specifically, reduced AE behaviors seem to distinguish the HRA+ASD infants from the other outcome groups. Also, this study found that increased TO and AE behaviors were associated with better performance on a cognitive assessment for all groups except HRA+ASD. These two findings are important, as they differentiate this outcome group from all others, suggesting that there may be a different set of mechanisms employed during a testing session for HRA+ASD infants. This study also found that AE risk did not contribute predictive value to a CRI for this disorder. Taken together these findings suggest that though temperament profiles appear to differ in HRA+ASD infants during the first year of life, this construct of behavior is not a valuable early behavioral risk marker for identifying ASD.

No description available.

U.S. incarceration rates have soared over the past three decades and the demographic characteristics of those who end up in prison are a reflection of the nation's structural inequality. Incarcerated fathers are a socially disadvantaged group and spending time in prison compounds already significant risk factors that these men experienced throughout their lives. In addition, it increases the risk that their children will suffer from the intergenerational transmission of social inequality. While studies indicate that maintaining contact between incarcerated fathers and their children has the potential to benefit them both and improve a variety of outcomes, there is limited research on the factors that impact incarcerated father-child contact. Based on the ecological model and the cumulative risk framework, this thesis attempts to help fill this gap in the current literature by examining whether an incarcerated father's cumulative risk factors impact the frequency of contact he has with his children. Using a nationally representative data set of men in state prisons and a negative binomial regression analysis, this study found that number of childhood risk experiences was a significant predictor of an incarcerated father's contact with his children. In addition, minority status moderated the relationship between childhood risk and frequency of visits, with an increased effect of risk on father-child contact for African American and Hispanic men. While the quadratic term of Risk² was not significant, disproving the hypothesis that there is a non-linear relationship between risk and contact, a visual representation of the distribution showed that contact between fathers and their children dropped substantially for men with the highest number of risk factors. This study provides valuable information about the relationship between the childhood experiences of incarcerated fathers and their subsequent social ties. The knowledge that childhood risk impacts frequency of father-child contact has the potential to inform interventions aimed at improving outcomes for these at-risk families. / Graduation date: 2013

The impact of school factors on academic achievement has become an important focus for school social work and revealed the need for a comprehensive school social work model that allows for the identification of critical areas to apply social work services. This study was designed to develop and test a more comprehensive school social work model. Specifically, the relationship between cumulative grade point average (GPA) and the cumulative risk index (CRI) and an additive risk index (ARI) were tested and a comparison of the two models was presented. Over 20,000 abstracts were reviewed in order to create a list of factors which have been shown in previous research to impact academic achievement. These factors were divided into the broad domains of personal factors, family factors, peer factors, school factors, and neighborhood or community factors. Factors that were placed under the school domain were tested and those factors which met all three criteria were included in the overall model. Consistent with previous research, both the CRI and ARI were shown to be related to cumulative GPA. As the number of risk factors increased, GPA decreased. After a discussion of the results, a case was made for the use of an additive risk index approach fitting more with the current state of social work. In addition, selecting cutoff points for determining risk and non-risk students was accomplished using an ROC analysis. Finally, implications for school social work practice on the macro-, meso-, and micro- levels were discussed.

Diagnostic X-rays are the most important man-made source of radiation exposure for the general population, contributing about 14% of the total annual exposure worldwide from all sources. However, although diagnostic X-rays provide great benefits, it is generally accepted that their use involves some small risk of developing cancer. The risk to an individual is probably small because radiation doses are usually low, but the large number of people exposed annually means that even small individual risks could translate into a considerable number of cancer cases. The aim of this work was to reestimate this risk on the basis of the annual number of CT examinations undertaken in the Czech Republic and typical doses applied. But there wasn't possible to find necessary data for planned reckonings by return, because their archiving isn't obligatory. This study, therefore, only describes common incidence of ionising radiation with human organism and further, all inevitable mathematically-physical equations needed for realization of primary planned investigation, with all necessary datal inputs included. In findings of this work there are drafted and demonstrated procedures, how to obtain and cultivate needed data ,so it was possible to compare it with technical literature.

Les populations sont exposées dans leur habitat à un nombre croissant de composés chimiques, dont les composés organiques semi-volatils (COSV). Ils se distribuent sur les surfaces, les phases particulaire et gazeuse de l’air et les poussières, participant ainsi à l’exposition des populations par ingestion, par inhalation et par contact cutané. Plusieurs de ces composés sont suspectés d’être toxiques pour l’Homme. L’objectif de cette thèse est d’évaluer, par une démarche d’évaluation des risques sanitaires, l’impact sur la santé publique des expositions aux COSV fréquemment détectés dans les logements français. Dans un premier temps, les expositions ont été estimées pour 32 composés à partir de données de contamination et de facteurs humains d’exposition comme le poids, le volume respiratoire, le temps passé dans l’habitat, etc. Les voies orale, pulmonaire et cutanée ont été agrégées pour les COSV les plus préoccupants présents dans l’habitat et pour plusieurs tranches d’âge de la naissance à 30 ans. Dans un second temps, les risques pour la santé humaine ont été modélisés à partir de ces expositions et des données disponibles sur leur toxicité. Chaque composé a été pris en compte individuellement mais également en mélange sous l’hypothèse d’additivité des doses. Ce travail a permis l’obtention de distributions représentatives des expositions des populations dans l’habitat en France et d’identifier les voies et les médias dominants pour chaque composé ainsi que les COSV les plus à risque pour une certaine proportion de la population française. / In housing, people are exposed to an increasing number of chemicals, including semivolatile organic compounds (SVOCs). SVOCs are present on surfaces, in the gas phase, airborne particles and settled dust. Humans are exposed through ingestion, inhalation and dermal contact. Many of these compounds have suspected toxic effects on human health. The objective of this thesis is to assess, by a risk assessment approach, the public health risk posed by the exposure to SVOCs frequently detected in French dwellings. At first, indoor exposures were estimated for 32 compounds from contamination data and human parameters such as body weight, inhalation rate, time spent in dwellings etc. Ingestion, inhalation and dermal contact exposure pathways were aggregated for the indoor SVOCs of greatest concern and for several age groups from birth to age 30. In a second step, human health risks were modeled from these exposures and from available toxicity data. Each SVOC was considered separately and also in mixtures, based on the assumption of dose additivity. This work provided exposures distributions representative of the French population and identified the dominant media and exposure routes for each compound as well as the most at risk SVOCs for a certain portion of the French population.

Les composés organiques semi volatils (COSV) sont largement présents dans les environnements intérieurs et sont suspectés d’être repro- ou neurotoxiques, mais peu de données sont disponibles quant à leur toxicité en mélanges. L’objectif de cette thèse est de proposer des indicateurs de toxicité cumulés pour les COSV détectés dans les logements français, dans un cadre d’évaluation des risques sanitaires cumulés. Les COSV ont été regroupés en fonction de leurs modes d’action communs, en lien avec les effets reprotoxiques (diminution de la concentration de testostérone sérique) et neurotoxiques (diminution de la viabilité neuronale). Des benchmark doses (BMD) ont ensuite été estimées par modélisation (modèle de Hill, PROAST, RIVM) des relations dose-réponse de la littérature décrivant la réponse d’intérêt. Des BMD comparables ont pu être estimées seulement pour 6 des 19 COSV reprotoxiques induisant une diminution de testostérone de 10 ou 50 % chez le rat adulte exposé par voie orale. Les facteurs de toxicité relatifs (RPF) estimés à partir des BMD sont sensiblement les mêmes en fonction du niveau de réponse (de 1600 pour le B(a)P à 0,1 pour le BBP), excepté pour le biphénol A qui passe de 7E+6 à 180. Considérant la mort neuronale in vitro, des BMD ont pu être estimées pour 13 COSV neurotoxiques, à partir de données provenant de différentes lignées et espèces. Les BMD équivalent à un niveau de réponse de 10 % s’échelonnent de 0,07 (PCB-153) à 95 µM (diazinon). L’originalité de ce travail repose sur le regroupement de composés de familles chimiques différentes qui constituent des contaminations réelles de notre environnement. Si l’estimation des quelques BMD a été possible à partir des données de la littérature, de nombreuses limites méthodologiques conduisent à émettre des recommandations en particulier sur la standardisation des protocoles expérimentaux et la disponibilité des résultats sous une forme adaptée à la modélisation de la relation dose-réponse. / Semi-volatile organic compounds (SVOCs) are widely present in indoor environments and are suspected to be repro- or neurotoxic but little is known on the health impact on SVOC mixtures. The objective of this work is to derive cumulative toxicity indicators for SVOCs detected in French dwellings in carrying forward a cumulative health risk assessment. SVOCs were grouped according to their repro- and neurotoxic common modes of action (i.e. decrease in serum testosterone concentrations, decrease in neuronal viability). Benchmark doses (BMDs) were then estimated by modeling dose-response relationships from scientific literature (Hill models, PROAST, RIVM). Comparable BMDs were estimated only for 6 of the 19 reprotoxic SVOCs which are responsible to 10 or 50% decrease in testosterone in adult male rats orally exposed. Estimated relative potency factors (RPFs) from BMDs are similar according to the response level (from 1600 for the B(a)P to 0.1 for the BBP), excepted for bisphenol A moving from 7E+6 to 180. For in vitro neuronal death, BMDs were estimated for 13 neurotoxic SVOCs using data from different cell lines and species. BMDs equivalent to a 10% of response range from 0.07 (PCB-153) to 95 µM (diazinon). The originality of this work is the grouping of compounds from different chemical families which we are really exposed to. BMDs estimation from published data was possible but many methodological limitations lead us to put forward recommendations especially on the standardization of experimental protocols and the availability of results in adapted format for dose-response relationship modeling.

No description available.