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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.
201

Prenatal Exposure to Binge Drinking and Cognitive and Behavioral Outcomes at Age 7 Years

Bailey, Beth Nordstrom, Delaney-Black, Virginia, Covington, Chandice Y., Ager, Joel, Janisse, James, Hannigan, John H., Sokol, Robert J. 01 September 2004 (has links)
The goal of this study was to examine differential effects of amount and pattern of prenatal alcohol exposure on child outcome. Alcohol use was assessed at each prenatal visit, and IQ and behavior were measured at age 7 years. After control for confounders, the amount of exposure was unrelated to IQ score and behavior for >500 black 7-year-old children. However, children who were exposed to binge drinking were 1.7 times more likely to have IQ scores in the mentally retarded range and 2.5 times more likely to have clinically significant levels of delinquent behavior. During prenatal care, clinicians should attend not only to amount but also to the pattern of alcohol intake, because of the elevated risk for cognitive deficits and long-term behavioral abnormality.
202

The Fecal Fermentation Profile of Twins and Infants with Opioid Exposure

Brown-Ezell, Dawson, Johnson, Michelle, Clark, W Andrew, Wahlquist, Amy 07 April 2022 (has links)
The Fecal Fermentation Profile of Twins and Infants with Opioid Exposure Dawson Brown-Ezell Michelle Johnson PhD, RD, LDN W. Andrew Clark PhD, RD Amy Wahlquist, PhD Introduction: The gut microbiome is believed to have a significant impact on health throughout the lifespan, and the influence of infant nutrition and other environmental factors are of particular interest in its development. The aim of this research project was to learn more about the microbiome and short chain fatty acid (SCFA) composition of toddlers of differing weights, considering birth history, environment, and diet. In East Tennessee, opioid misuse is a growing issue, and a number of participants in this study were exposed in utero. We also hoped to identify related effects on infant’s SCFA composition. Finally, it has been concluded that twins share a variety of traits, but much about their microbiome is unknown. With several pairs of twins in the sample, we aimed to identify any associations with SCFAs in this group. Methods: With informed consent, the child’s history was obtained, including age, birth length and weight, delivery type (C-section or vaginal), and feeding method (breast, bottle fed, or both). The child’s current weight, height, and BMI %ile were determined. Caregivers completed the 90-question Block Questionnaire for Ages 2-7 Kids food frequency questionnaire, and results were analyzed by Berkeley Analytics Inc (dba NutritionQuest). Participant-provided stool samples were freeze-dried and ground, and SCFAs were extracted and analyzed by content and concentration. Data analysis was generated using SAS software, Version 9.4 of the SAS System, Copyright © 2013 SAS Institute Inc. Results: Nine SCFAs were measured in duplicate, and the concentrations averaged. Statistical analysis included comparisons of SCFAs related to factors including weight status, infant feeding modality, twin status, and intrauterine drug exposure, and significance determined with a p value < 0.05. Results did not identify significant differences in individual SCFA concentrations between obese and non-obese toddlers, however concentrations of isobutyrate, isovaleric acid, and octanoic acid were greater in toddlers who were formula fed as infants versus toddlers who were breastfed, and those fed a combination of breastmilk, and formula. Analysis further revealed a higher mean concentration of caproic and propionic acid in twin subjects. Of particular interest, toddlers with a history of opioid exposure had higher mean concentrations of isovaleric and octanoic acids, but less isocaproic acid when compared to those who were not drug exposed. Further analysis will help determine if these findings may be related to nutrient intake, in particular dietary fiber intake.
203

Secondhand smoke and vapor exposure in youths: challenges facing physicians in addressing this complex problem

Bueno, Brian Thomas 11 June 2019 (has links)
The dangers of secondhand smoke (SHS) exposure on the human body were initially reported in 1972, just eight years after the negative effects of smoking on smokers was reported. The Surgeon General of the United States systematically expanded (and continues to expand) the warnings over time, as new scientific evidence becomes available. Warnings, which began to incorporate youths in 1975, emphasized the need to pay particular attention to fetuses, newborns, infants, children, adolescents, and young adults since they rely on parents, guardians, and other adults to keep them safe. Although fewer in number than adults, the diseases that are causally linked to smoking and exposure to SHS in youths are also complex and can result in death (i.e., sudden infant death syndrome). The introduction of new tobacco products, such as low nicotine cigarettes and electronic cigarettes, prompted the Surgeon General to release additional warnings. In 2016, the Surgeon General advised the nation that more information will become available as the electronic cigarette manufacturers comply with new Tobacco Control Act requirements to report harmful vapor constituents. Physicians need to keep abreast of the vast and growing body of knowledge related to the biological and chemical components of SHS and vapor, as well as the dangers that SHS and vapor cause. To ease the burden on physicians, the federal government and medical professional societies created clinical practice guidelines which summarize the literature related to the dangers of SHS and make recommendations for medical management. Guidelines recommend that physicians and other clinicians should offer smoking cessation advice and intervene to limit youth exposure to SHS. Although the approach recommended for use with patients in a physician’s office is clear and attempts to streamline the processes have been made, the identification and counseling process for smoking cessation and eliminating SHS exposure remains time consuming. Barriers to payment make it difficult for physicians to be adequately reimbursed for their efforts to keep their patients safe from the dangers of SHS and vapor exposure. More work is needed to be able to continue to reduce the percentage of youths exposed to SHS in their environments. Additional attention is needed to address the racial and ethnic disparities that are evident in the scientific literature.
204

Importance of Exposure Time on Digital Image Correlation (DIC) at Extreme Temperatures

Thai, Thinh Quang 01 May 2018 (has links)
Extreme temperatures have increasingly played an important role in engineering applications, including leading edges during hypersonic flight, spacecraft re-entry, and propulsion systems. In order to design for such thermo-mechanical conditions, materials must be characterized using suitable measurement methods. DIC is a popular and versatile method in full-field measurement. In brief, DIC compares images of a sample between its undeformed and deformed state in order to get displacement and strain field maps. Since the images are acquired from digital cameras, it is important to have high contrast images for meaningful correlation. Exposure time is a pivotal camera setting relating to camera sensitivity. Alteration in exposure time results in variation of image contrast, thereby affecting DIC correlation. Also, it is well known that at extreme temperatures, materials emit light which can saturate DIC camera sensors, but the light can be mitigated using optical bandpass filters. In previous work, many have shown that blue bandpass filters can effectively extend the temperature range of DIC, and our lab has shown that ultraviolet (UV) filters can extend the range further. In this thesis, four different temperatures: room temperature, 1300°C, 1450°C, and 1600°C were tested by rigid-motion experiments. At each temperature level, UV images were acquired in order to examine the variation of DIC error over the whole range of exposure time. UV images were acquired at exposure times ranging from 500μs to 61,000μs, which are the minimum and maximum possible values for the cameras used in this thesis. The results showed that there were higher errors of UV-DIC at extremely dark or bright exposure times where as errors were generally insignificant at intermediate exposure times. In order to perform meaningful DIC up to 1600oC, the exposure time for the camera used in this thesis is suggested to be set between 10,000μs and 40,000μs.
205

Cambrian Stratigraphy in the Northern Wasatch Region

Maxey, George Burke 01 May 1941 (has links)
An exhaustive field study of the Cambrian stratigraphy of the northern Wasatch region indicates that in addition to the Blacksmith Fork section there are two complete and better exposed middle and upper sections. Several other good exposures of the lower Middle Cambrian section have been studied in detail. The Spence shale is found to be a member low in the Langston, not the basal member of the Ute. Relative ages of the Spence shale and Ptarmigania faunas have been determined. Other Cambrian faunal zones have been discovered and are discussed. Paleontologic evidence suggests that the Nounan formation is of Upper Cambrian (Cedaria) age. Laboratory and field evidence indicates the probable Lower Cambrian age of the Brigham formation.
206

Physiological, Behavioral, and Self-Report Outcomes of Acceptance and Regulation Approaches to Exposures for Intrusive Thoughts

Smith, Brooke M. 01 August 2019 (has links)
Cognitive-behavioral therapy that includes exposure, or intentionally and systematically confronting feared situations, is the gold standard psychological treatment for obsessive-compulsive disorder. However, less than half of those who begin this treatment are considered to have recovered from their disorder at the end of treatment, and this number is even smaller in the months following the end of treatment. Leading theories regarding how treatment changes occur focus on reducing fear, and they do not include “voluntary” (i.e., operant) behaviors, such as avoidance, that are key features of the disorder. Acceptance-based approaches to exposure do not focus on fear reduction, but directly focus on changing “voluntary” behaviors. Combining these two perspectives could lead to a better understanding of how exposure works and, ultimately, lead to more effective and long-lasting psychological treatments for obsessive-compulsive disorder. The current study investigated whether accepting distress or attempting to reduce distress during exposure for intrusive thoughts led to different outcomes and whether they led to these outcomes in different ways. Participants with intrusive thoughts were randomized to three groups, Acceptance (n = 23), Regulation (n = 20), and Control (n = 21), and completed two sessions 1week apart. Participants in the Acceptance and Regulation groups completed a 30-minute exposure at session 1 and 6 days of 10-minute exposures at home; Control participants watched videos of the same lengths. Self-report questionnaires, measures of behavior, self-ratings, and physiological data were collected at both sessions. Results showed that Acceptance and Regulation groups decreased on measures of obsessive-compulsive symptom severity, rituals performed, self-rated distress, and skin conductance levels. Acceptance showed lower skin conductance and a statistical trend toward greater self-rated willingness to experience distress than Regulation, as well as greater psychological flexibility than Control. There were no between group differences in the number of exposure tasks completed during a behavioral test, psychological inflexibility, valued living, or heart rate. This study suggests that psychological flexibility and willingness to experience distress may paradoxically lead to decreased physiological arousal, findings which may inform future research and treatment approaches.
207

The Effects of Video Game Difficulty Selection on Flow Experience

Buncher, Michael W. 14 May 2013 (has links)
No description available.
208

Vitamin D Sub-set Analysis from the Flash Study

Bishop, Megan, Hall, Laura, McDermott, Ann, Nazmi, Aydin 01 March 2012 (has links) (PDF)
Vitamin D is important to the health of college students. The objective of our study was to measure sun exposure, skin pigmentation, vitamin D intake, and serum 25-hydroxyvitamin D (25[OH]D) in a subset of participants from The Following the Longitudinal Aspects of Student Health (FLASH) Study to determine the best predictors of 25(OH)D status. Participants were college-aged freshman who had their blood drawn in spring (Visit 1) and fall 2010 (Visit 2) at California Polytechnic State University (Cal Poly), San Luis Obispo, CA. (35.3°N). Vitamin D intake was measured using a 28-day food frequency recall questionnaire (specific to vitamin D foods and supplements) while questions specific to the frequency of milk and fish intake were accessed from the FLASH questionnaire. Sun exposure was measured using a 28-day recall questionnaire (time in sun and sun exposure index [SEI]) and questions (frequency of weekday/ weekend exposure) from the FLASH questionnaire. Skin pigmentation was measured using a reflectance spectrophotometer. Serum 25(OH)D was measured at a local pathology lab as measured by an IDS-iSYS. Means (SD) were as follows (n= 40): reflectance of the forehead was 61 (3.5) L* (Lightness) for Visit 1 and 61 (4.3) L* for Visit 2. Vitamin D intake was 308 (234) IU for Visit 1 and 316 (257) IU for Visit 2. Time outside was 81 (44) mins for Visit 1 and 76 (39) mins for Visit 2. Serum 25(OH)D was 85 (24) nmol/L for Visit 1 and 113 (28) nmol/L in Visit 2 which was significantly higher (p < 0.0001). The SEI was 53 (38) body surface area (BSA) exposed (m2) x mins for Visit 1 and 55 (34) m2 x mins Visit 2. Although 90% of participants in Visit 1 and 88% in Visit 2 were below the RDA guidelines for vitamin D intake (600 IU/day), 5% of participants in Visit 1 and none in Visit 2 had serum 25(OH)D serum levels < 50 nmol/L (the recommended level of sufficiency for bone health), demonstrating the importance of sun exposure to vitamin D status in these college students. To determine the strongest predictors of status we used regression analysis to predict serum 25(OH)D with skin reflectance, vitamin D intake, and sun exposure. We found that weekend sun exposure, fish intake, and forehead skin reflectance were the strongest predictors of serum 25(OH)D (R2= 0.50, p= 0.0010) demonstrating that simple questionnaires can help to predict serum 25(OH)D status.
209

Effective exposure: lag-parameterized exponential models for exposure risk

Gerlovin, Hanna 13 November 2018 (has links)
Many observational studies assessing the effects of treatments or exposures are limited to comparisons between treatment users and nonusers or exposed and unexposed participants at study entry. However, the underlying and etiologically relevant exposure may gradually increase over time before reaching some plateau. This amount of time required for this latent cumulative exposure to reach a maximum hazard will be referred to as the "lag", coming from the concept that the association between exposure and outcome is lagged or delayed. Accounting for the lag is essential when analyzing exposure-response associations adequately. My challenge was to simultaneously estimate the lag-time and the exposure's lagged-association with the outcome at plateau. In this dissertation, I draw an analogy with the pharmacokinetic one-compartment model (OCM). OCM describes the accumulation of a medication in the body based on an exponential cumulative density function whose rate of increase is defined by a half-life parameter. Upon discontinuation, the OCM assumes that a medication will eliminate at the same half-life rate. The decline, for my purposes, can be interpreted as the time to return to a null effect of exposure, which occurs at roughly 4-5 half-lives. My methods model the association of a latent exposure and dichotomous outcome using a half-life of effect, similar to the OCM, in longitudinal analyses of single and repeated exposures. I derive profile likelihood-based algorithms to estimate of the upper limit of association simultaneously with the rate of latent exposure growth towards or away from plateau. Lastly, I extend this approach to allow different half-life parameters for incline and decline. Using simulations, I analyze the performance of my approach by comparing bias and coverage of the estimates for the half-life and effect parameters. With data from the Black Women's Health Study Cohort (a prospective cohort of 59,000 women followed 1995-2015), I show that prolonged cigarette smoking is associated with a maximum hazard of cardiovascular disease (CVD) at 2.5 times the hazard of never smokers. Additionally, I estimate that it takes about 7 years of smoking cessation for an individual's hazard of CVD to decrease by 50%. / 2020-11-13T00:00:00Z
210

Parenting style moderates the relationship between childhood exposure to violence and sexually aggressive behavior in early adulthood

Beck-Xaysuda, Lisa 06 August 2011 (has links)
A relationship between childhood exposure to violence and the perpetration of sexual aggression in young adulthood has recently been established. In addition to replicating the relationship between these variables, this study also examined parenting style as a factor that may moderate this correlation. In this study, 903 college students completed an online survey assessing childhood exposure to violence, sexual aggression, and parenting variables. Childhood exposure to violence was correlated to the perpetration of sexual aggression in young adulthood. Also, the way in which individuals believed they were parented during childhood moderated the relationship between exposure to violence and sexual aggression. Both the optimal and affectionate constraint parenting styles significantly reduced correlations between exposure to violence and sexual aggression.

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