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The Trajectory of Alcohol Use in Emerging Adulthood: Investigating the Roles of Alcohol Measurement and Educational PathwaysThompson, Kara 04 December 2013 (has links)
Inconsistencies in alcohol use measurement across studies and broad conceptualizations of post-secondary education experiences of young adults impede the comparison of research findings and our understanding of age-related shifts in alcohol use during emerging adulthood. This dissertation uses data from the Victoria Health Youth Survey (V-HYS), a 5 wave longitudinal study following 662 Canadian youth across the ages of 12-27. Study 1 examined the longitudinal associations among four measures of alcohol consumption (frequency, quantity, frequency of heavy episodic drinking and volume) from ages 15-25 and compared the ability of these measures to predict alcohol-related problems in emerging adulthood. Levels and rates of change across alcohol dimensions were moderately associated over time. However, measures of alcohol involvement significantly differed in their average rate of growth and in the prediction of alcohol-related problems in emerging adulthood. Heavy episodic drinking and volume showed the strongest associations in developmental trends and were similarly predictive of alcohol-related problems. The findings from this study support using measures of heavy episodic drinking or volume for assessing alcohol use and alcohol-related problems during emerging adulthood. Building on Study 1, Study 2 compared the trajectories of heavy episodic drinking during adolescence and emerging adulthood among youth in four different educational pathways: two-year college students, four-year university students, transfer students, and terminal high school graduates. This study also examined whether individual level factors could account for group differences in heavy drinking among the education groups. Terminal high school graduates consistently had the highest levels of alcohol use over time compared to all three post-secondary groups. Two-year college students had significantly higher levels of heavy drinking than university or transfer students when they enrolled, but university students had the greatest increases in heavy drinking after enrollment. However, differences in heavy drinking between post-secondary groups were completely accounted for by variations in the age at the time of enrollment. Taken together, the current findings illustrate that enrolling in post-secondary education, regardless of the type of institution, is associated with an increase in the frequency of heavy drinking during emerging adulthood and that this increase is greatest for younger students. However, the rates of drinking never exceeded that of the terminal high school graduates over time. These studies illustrate that the conclusions drawn about alcohol use trends during emerging adulthood may be contingent on the alcohol consumption measure used and conceptualizations of educational experiences. The results of the current studies provide recommendations to researchers about which measures of alcohol involvement to select for inclusion in future studies, and inform the optimal timing, targets, and contexts for alcohol prevention and intervention efforts during emerging adulthood. / Graduate / 0620
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Informative Prior Distributions in Multilevel/Hierarchical Linear Growth Models: Demonstrating the Use of Bayesian Updating for Fixed EffectsSchaper, Andrew 29 September 2014 (has links)
This study demonstrates a fully Bayesian approach to multilevel/hierarchical linear growth modeling using freely available software. Further, the study incorporates informative prior distributions for fixed effect estimates using an objective approach. The objective approach uses previous sample results to form prior distributions included in subsequent samples analyses, a process referred to as Bayesian updating. Further, a method for model checking is outlined based on fit indices including information criteria (i.e., Akaike information criterion, Bayesian information criterion, and deviance information criterion) and approximate Bayes factor calculations. For this demonstration, five distinct samples of schools in the process of implementing School-Wide Positive Behavior Interventions and Supports (SWPBIS) collected from 2008 to 2013 were used with the unit of analysis being the school. First, the within-year SWPBIS fidelity growth was modeled as a function of time measured in months from initial measurement occasion. Uninformative priors were used to estimate growth parameters for the 2008-09 sample, and both uninformative and informative priors based on previous years' samples were used to model data from the 2009-10, 2010-11, 2011-12, 2012-13 samples. Bayesian estimates were also compared to maximum likelihood (ML) estimates, and reliability information is provided. Second, an additional three examples demonstrated how to include predictors into the growth model with demonstrations for: (a) the inclusion of one school-level predictor (years implementing) of SWPBIS fidelity growth, (b) several school-level predictors (relative socio-economic status, size, and geographic location), and (c) school and district predictors (sustainability factors hypothesized to be related to implementation processes) in a three-level growth model. Interestingly, Bayesian models estimated with informative prior distributions in all cases resulted in more optimal fit indices than models estimated with uninformative prior distributions.
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A Bayesian Synthesis Approach to Data Fusion Using Augmented Data-Dependent PriorsJanuary 2017 (has links)
abstract: The process of combining data is one in which information from disjoint datasets sharing at least a number of common variables is merged. This process is commonly referred to as data fusion, with the main objective of creating a new dataset permitting more flexible analyses than the separate analysis of each individual dataset. Many data fusion methods have been proposed in the literature, although most utilize the frequentist framework. This dissertation investigates a new approach called Bayesian Synthesis in which information obtained from one dataset acts as priors for the next analysis. This process continues sequentially until a single posterior distribution is created using all available data. These informative augmented data-dependent priors provide an extra source of information that may aid in the accuracy of estimation. To examine the performance of the proposed Bayesian Synthesis approach, first, results of simulated data with known population values under a variety of conditions were examined. Next, these results were compared to those from the traditional maximum likelihood approach to data fusion, as well as the data fusion approach analyzed via Bayes. The assessment of parameter recovery based on the proposed Bayesian Synthesis approach was evaluated using four criteria to reflect measures of raw bias, relative bias, accuracy, and efficiency. Subsequently, empirical analyses with real data were conducted. For this purpose, the fusion of real data from five longitudinal studies of mathematics ability varying in their assessment of ability and in the timing of measurement occasions was used. Results from the Bayesian Synthesis and data fusion approaches with combined data using Bayesian and maximum likelihood estimation methods were reported. The results illustrate that Bayesian Synthesis with data driven priors is a highly effective approach, provided that the sample sizes for the fused data are large enough to provide unbiased estimates. Bayesian Synthesis provides another beneficial approach to data fusion that can effectively be used to enhance the validity of conclusions obtained from the merging of data from different studies. / Dissertation/Thesis / Doctoral Dissertation Psychology 2017
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An Examination of Mexican American Adolescent and Adult Romantic RelationshipsJanuary 2014 (has links)
abstract: This dissertation examined Mexican American individuals' romantic relationships within two distinct developmental periods, adolescence and adulthood. Study 1 used latent class analysis to explore whether 12th grade Mexican Americans' (N = 218) romantic relationship characteristics, cultural values, and gender created unique romantic relationship profiles. Results suggested a three-class solution: higher quality, satisfactory quality, and lower quality romantic relationships. Subsequently, associations between profiles and adolescents' adjustment variables were examined via regression analyses. Adolescents with higher and satisfactory quality romantic relationships reported greater future family expectations, higher self-esteem, and fewer externalizing symptoms than adolescents with lower quality romantic relationships. Similarly, adolescents with higher quality romantic relationships reported greater academic self-efficacy and fewer sexual partners than adolescents with lower quality romantic relationships. Finally, adolescents with higher quality romantic relationships also reported greater future family expectations and higher academic self-efficacy than adolescents with satisfactory quality romantic relationships. To summarize, results suggested that adolescents engaged in three unique types of romantic relationships with higher quality being most optimal for their adjustment. Study 2 used latent growth modeling to examine marital partners' (N = 466) intra- and inter-individual changes of acculturative stress, depressive symptoms, and marital quality. On average across the seven years, husbands' acculturative stress remained steady, but wives' significantly decreased; partners' depressive symptoms remained relatively steady, but their marital quality significantly decreased. Although partners' experiences of acculturative stress were less similar than their experiences of depressive symptoms and marital quality, overall their experiences were interconnected. Significant spillover and crossover effects emerged between partners' initial levels of acculturative stress and depressive symptoms and between depressive symptoms and marital quality. Moreover, changes in husbands' depressive symptoms were negatively associated with changes in their marital quality. Overall, results suggested that partners' experiences were interconnected across time. / Dissertation/Thesis / Ph.D. Family and Human Development 2014
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Nonresident Fathers’ Care-Provision Trajectory: Growth Mixture Modeling ApproachKo, Kwangman 03 April 2020 (has links)
The current study identified subgroups of individuals regarding nonresident fathers’ childcare provision by taking the growth mixture modeling approach (GMM) and Fragile Families and Child Wellbeing Study (FFCWS; wave 1 to wave 5). The three-profile model was the most fitted model, where Profile 1 (n = 548, 68.7%) showed the lowest childcare across waves, and Profile 3 (n = 106, 13.3%) was the most involved group, and the Profile 2 (n = 144, 18.0%) showed moderate levels of care provision (see Figure 1). Follow-up analysis revealed that the profiles significantly differed on child gender and the fathers’ education level; participants were more likely to be in the Profile 3 when the child was boy and fathers had higher education achievement.
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EFFECTS OF SOW GUT MODIFYING FEED ADDITIVES ON REPRODUCTIVE CHARACTERISTICS AND PROGENY GROWTH PERFORMANCEMorgan T Thayer (10723725) 29 April 2021 (has links)
<p>Providing wholesome pork products to consumers involves raising healthy pigs to grow well and be feed efficient from birth to market. Raising these pigs starts with ensuring the sow is healthy and provided good nutrition in gestation and lactation. Therefore, this dissertation primarily focuses on research of gut modifying feed additives fed to sows in gestation and lactation (and to their progeny in Chapter 3) to enhance reproductive performance and litter growth to weaning (and in the nursery). In Chapter 2, a total of 606 sows and their progeny were used to determine if feeding gestating and lactating sows a proprietary strain of Pichia guilliermondi as a whole-cell inactivated yeast product (WCY; CitriStim, ADM Animal Nutrition, Quincy, IL) improves sow and litter performance in a commercial production system. Sows were fed a control (CON) diet or control diet fortified with 0.15% of the WCY from d 35 of gestation through lactation. Sows supplemented with WCY in gestation and lactation had a greater number of total born piglets by 0.45 pigs (P < 0.04), piglets born alive (P < 0.04), heavier born alive litter weights (P < 0.001), and greater post cross-foster litter size (P < 0.001) compared to CON fed sows. Litter size at weaning was increased by 0.54 pigs when sows were fed WCY compared to CON (P < 0.001). However, litter weaning weights and 21-day adjusted litter weaning weights were similar (P > 0.158) with the 21-day adjusted litter weaning weights being numerically greater for the WCY sows. The average piglet weaning weights from CON fed sows were heavier by 0.35 kg compared to WCY (P < 0.001). This increase in body weight of piglets from CON fed sows is partially explained by their 0.93 days longer lactation (P < 0.001) and may also be due to the smaller litter size nursed throughout lactation. The percent of litters treated for scours decreased from 38.3% to 14.2% when sows were fed WCY (P < 0.001). The distribution of birth and weaning weights was not different (P > 0.2461) between treatments.</p><p>Chapter 3 encompasses a sow experiment where progeny were followed onto the nursery for a 28-d study. Forty-seven sows and their progeny were used to determine if feeding gestating and lactating sows a Bacillus licheniformis direct-fed microbial (DFM), an organic acid blend of medium and short-chain fatty acids (OA), or in combination improves sow lactation feed and water intake, litter growth, and subsequent reproductive performance. At weaning, offspring were fed a positive control diet (PC), negative control diet (NC), or a diet representative of their dam’s treatment to determine if there is an additive benefit to also feeding DFM and/or OA to nursery pigs in addition to their dams. On approximately d 80 of gestation, sows were fed one of four diets in a 2 2 factorial design: 1) gestation control (CON), 2) CON with DFM (1.6x109 CFU/kg of complete feed), 3) CON with 0.4% OA, 4) CON with both DFM and OA. Dietary treatments were also fed throughout lactation. Sows fed the OA diets had fewer mummies per litter (P < 0.010) compared to diets not containing OA. Sows fed diets with the DFM gave birth to lighter pigs born alive (1.5 vs. 1.7 kg; P < 0.003) compared to non-DFM fed sows, and a tendency for an interaction (P < 0.092) existed where feeding DFM+OA lessened the decrease in born alive BW. There was a tendency (P < 0.093) for pigs from DFM fed sows to also be lighter at weaning (5.8 vs. 6.2 kg) compared to pigs from sows not fed DFM, with no differences in litter sizes at weaning (P < 0.815). There was a tendency (P < 0.079) for the DFM to decrease the amount of sow BW loss in lactation compared to sows not fed the DFM (approximately 6 vs. 8% BW loss, respectively). The maintained BW in lactation was likely related to DFM sows numerically (P < 0.124) consuming 8.4% more feed during d 7-14 of lactation and 6.4% more feed (P < 0.234) from d 1 of lactation to weaning. The interaction was approaching a trend (P < 0.133) where sows fed DFM returned to estrus 1.0 day sooner than CON, but only 0.4 days sooner when sows were fed the DFM+OA diet.</p><p>Progeny weaned from these sows (n = 384, Initial BW = 6.15 kg) were blocked by initial BW and sex and allotted (6 pigs/pen, 8 pens/treatment) to one of 8 nursery treatments. Pigs from CON sows were fed a negative (NC; no antibiotics, no pharmacological Zn or Cu) or positive (PC; neomycin-oxytetracycline in phases 1 and 2 (827 and 551 ppm) and carbadox in phases 3 and 4 (55 ppm)) control diet. Pigs from sows fed DFM, OA, or DFM+OA were fed the NC diet or a diet representative of their dam’s treatment. Diets with DFM contained 1.6x109 CFU/kg of complete feed and diets with OA contained 0.5, 0.4, 0.3, and 0.0% OA in phases 1-4, respectively. Weaning weight was used as a covariate for nursery performance due to the DFM offspring being significantly lighter at weaning. For all phases and overall, PC fed pigs had greater ADG (P < 0.003) and ADFI (P < 0.059) than NC pigs. PC fed pigs had greater G:F (P < 0.010) than NC pigs for all phases and overall except d 21-28 (P < 0.532). Feeding DFM or OA in sow diets improved (interaction; P < 0.049) nursery pig G:F, but DFM+OA offspring had similar G:F compared to NC pigs from CON fed sows for d 7-14, 0-14, 0-21, and 0-28. Feeding DFM or OA to sows and their progeny decreased ADFI (interaction; P < 0.042) but improved G:F (interaction; P < 0.028) for d 7-14 and 0-14 with DFM+OA having similar performance to NC. For d 14-21 and 0-21, feeding DFM or OA to sows and their progeny decreased ADFI whereas DFM+OA increased ADFI above NC (interaction; P < 0.019). Overall, d 0-28, feeding DFM or OA to sows and their progeny improved G:F (interaction; P < 0.001) with DFM+OA having poorer G:F compared to NC. When the DFM was fed to sows and nursery pigs, progeny harvested on d 6 post-weaning had a decreased ratio of villus height to crypt depth (P < 0.035) compared to sows and pigs not consuming the DFM (average 1.34 vs. 1.67). Comparing pigs fed PC vs. NC from CON fed sows, expression of interleukin 10 (IL-10) was greater (0.51-fold increase; P < 0.046) for NC pigs than PC pigs. Expression of occludin (OCLN) was lower (P < 0.010) when OA was fed to the sows and pigs compared to when OA was not fed to the sows and pigs (0.78 vs. 1.00, respectively).</p><p>Chapter 4 is the only chapter that does not include maternal nutrition. In this chapter, maternal line gilts (Topigs Norsvin TN70) were bred with frozen semen from Duroc boars born from 2000 to 2017 divided into two genetic groups: semen from boars born in 2000 to 2005 and 2011 to 2017. These genetic groups had vastly different terminal sire indexes (TSI) of 88.2 and 112.0 for 2000 to 2005 and 2011 to 2017, respectively. A total of 155 pigs were weaned into 44 pens in a wean-to-finish facility to determine if genetics from two decades of sires and sex of the progeny impact progeny growth performance and carcass characteristics. The expected large growth performance differences indicated by the TSI’s of the two genetic groups were not observed. However, barrows had greater feed intake (P < 0.031) and fatter carcasses (P < 0.004) than the more feed efficient (P < 0.006) and leaner (P < 0.015) gilts in this study. Modern swine genetics have been selected to be leaner and results from this study agree, although the differences in live scan and carcass measurements were not as large as expected. The lack of differences between genetic groups could possibly be due to environmental differences including nutrition and rearing conditions from when these sires were alive compared to what was experienced by these progeny.</p><p>In conclusion, feeding gestating and lactating sows a proprietary strain of Pichia guilliermondi as a whole-cell inactivated yeast product increased the number of piglets born and weaned as well as decreased the prevalence of scours during lactation. Feeding a Bacillus licheniformis DFM to sows may decrease pig born alive weight and subsequent weaning weight but reduce sow BW loss through 6.4% more lactation feed intake, quickening the return to estrus. Other than decreasing the number of mummies per litter, feeding the OA alone or in combination did not improve sow reproductive or litter growth performance in this study. Feeding DFM or OA to sows or their offspring may improve nursery feed efficiency but did not result in a difference in ADG or final BW in this study. Feeding the combination diet (DFM+OA) to the sow and nursery pigs tended to increase ADFI. Feeding antibiotics post-weaning continued to improve pig growth performance resulting in 2.7 kg heavier pigs at the end of the 28-d nursery period. Lastly, the expected large growth performance differences indicated by the TSI’s of two genetic groups created by using frozen semen from boars born in 2000 to 2005 and 2011 to 2017 were not observed.</p>
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A longitudinal latent growth modeling perspective on communication apprehension, self-perceived communication competence, and willingness to communicateHodis, Georgeta Mioara 01 January 2009 (has links) (PDF)
This dissertation proposed and operationalized a theoretically meaningful and practically useful conceptualization of change for three well known communication constructs, namely willingness to communicate (WTC), self-perceived communication competence (SPCC), and communication apprehension (CA). Specifically, this research found that students' WTC and SPCC scores increased linearly during the semester and their CA scores decreased linearly. In addition, results from this dissertation indicated that for all three constructs considerable differences among students existed with respect to both initial levels and subsequent change in levels. These results are important and can advance the theoretical communication research centered around these constructs. In particular, knowledge that the hypothesis of linear change in the constructs received support from empirical data and that variations in students' trajectories of change were recorded, can prompt communication scholars to search for novel theoretical frameworks that can explicate these change processes. Moreover, the findings of this research are also salient for classroom instruction. Specifically, teachers of introductory communication classes can use the results of this study as broad benchmarks that can inform realistic expectations with respect to students' improvement in WTC, SPCC, and/or CA. In addition, this dissertation presented the benefits derived from properly conceptualizing and studying change by means of latent growth modeling, a powerful and versatile data analytic technique. Specifically, employing this methodology offered the opportunity to get detailed information about how changes in one construct are related to changes in the other two constructs and to gain a more in-depth knowledge of the intricate ways in which interlinkages among the constructs change across time. The benefits of this dynamic way to study WTC, SPCC, and CA are readily apparent as it facilitates teachers access to information that can be used to tailoring their activity for a more targeted, efficient, and beneficial instruction.
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Bacteria Growth Modeling using Long-Short-Term-Memory NetworksShojaee, Ali, B.S. 29 September 2021 (has links)
No description available.
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Patterns and Associations of Shoreline Erosion and Developed Land Use Change in the Lower Meghna Estuary of BangladeshHuda, Nazmul 23 January 2023 (has links)
Population living along the coast are at risk of losing land, households, and economic resources due to the hazards of coastal erosion. Scientific research has indicated that 70% of the planet's sandy coastal environment is being impacted by coastal erosion. Due to the different characteristics of the lands in the coastal zone versus other areas, it is important to understand how the hazard of shoreline erosion contributes to subsequent land use change in affected coastal regions. This study analyzes how the level of erosion, land loss, and developed land loss performs when added with the default land use change parameters such as existing developed land proximity, proximity to forested areas, population, transportation, etc. Sample points of 1020 from 10 years and 15 years of shoreline erosion data for the lower Meghna River estuary of Southeast Bangladesh have been obtained and from there, different erosion statistics have been developed. Developed land use data has been collected from ESA's World Settlement Footprint dataset and other datasets are also collected from secondary data sources. Logistic regression modeling shows that there are verified contributions of proximity to erosion and amount of land loss with the probability of developed land use conversion in the study area. Adding the variables of environmental hazards increases the prediction accuracy by 2-3% and overall, the models are at least 85% accurate. / Master of Science / Population living along the coast are at risk of losing land, households, and economic resources due to the hazards of coastal erosion. The coast of the Lower Meghna estuary in Bangladesh is a region experiencing chronic and severe shoreline erosion that causes the land to be lost to estuarine waters. This research quantifies the amount of land lost to erosion with a special focus on the amount of developed land that is lost. Developed land in this study is defined as a built-up area typically composed of buildings and roads. The research also evaluates the effects of lost land on the subsequent conversion of interior land from a non-developed to developed status. The main contribution is to quantitatively identify the association between the erosion-induced land loss to future land use conversion. Using statistical modeling and digital mapping methods, results show that loss of land is associated with the subsequent conversion of non-developed land to developed land use. In particular, conversion has a higher probability at sites that are located more distant from the eroding shoreline that also are proximal to shoreline sites with higher rates of erosion-induced land loss. These results are suggestive of a relocation process where previously lost developed land is reestablished at interior sites within five kilometers of the eroding shoreline.
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Ethnoracial Comparisons in Psychotherapy Outcomes Among Native Hawaiian and Pacific Islander College StudentsCline, Jared Isaac 01 June 2019 (has links)
Variables such as stigma, weak ethnic identity, and cultural mistrust have been linked to the underutilization of therapy amongst ethnic minority populations. As such, ethnic minority populations may reach a higher threshold of distress-including areas such as anxiety and depression-before seeking professional help. While there is substantial research documenting ethnic differences among various ethnic minority populations (e.g., African Americans, Asian Americans, Hispanics) very little research has been conducted exploring differences among individuals from Native Hawaiian and Pacific Islander (NHPI) backgrounds. For the current study, we explored differences in distress upon intake as well as the change in anxiety and depression scores over the course of 12 therapy sessions for NHPI college students compared to college students from other ethnic groups. We also explored the effect that spirituality and religiosity had on depression and anxiety among NHPI college students. We collected data from the Center for Collegiate Mental Health (CCMH), a practice research network that has aggregated data from hundreds of university counseling centers across the United States, from the years 2012-2015. Our total sample was N = 256,242; of that sample, n = 452 identified as NHPI. We selected independent variables from the Standardized Data Set (i.e., ethnicity, age, gender, estimated socioeconomic status, importance of spirituality and religiosity) and dependent variables from the Counseling Center Assessment of Psychological Symptoms-62 and -34 (i.e., depression, social anxiety, generalized anxiety). We analyzed data using latent growth modeling and computed a conceptual effect size by comparing the change in standard deviation between treatment effects. Results yielded significant differences (p < .05) between both intercept and slope estimates for NHPIs compared to African Americans, Hispanics, Asian Americans, and Whites. Notably, NHPI depression scores improved at the highest rate over time compared to other ethnic groups, while anxiety scores among NHPIs improved at the lowest rate. The effect of spirituality and religiosity on anxiety and depression was statistically insignificant. The results of this study indicated that NHPI college students experience psychotherapy outcomes differently than other ethnic groups, including Asian Americans, with moderate-to-large magnitudes of effect. Considering substantial meta-analytical research supporting the benefits of culturally adapted treatment, results of this study suggest the need to disaggregate the combined demographic Asian Americans and Pacific Islanders (AAPI), as research conducted on this broader group provides questionable validity when applied to clinical settings for NHPIs.
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