Theses and Dissertations from UMD
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Item EXAMINATION OF THE ASSOCIATIONS BETWEEN SELECTED PERFLUOROALKYL SUBSTANCES AND THEIR ISOMERS WITH BODY WEIGHT IN ADOLESCENTS USING NHANES 2013-2018(2023) Snyder, Jessica A; Payne-Sturges, Devon; Maryland Institute for Applied Environmental Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)0ABSTRACT Title of thesis: EXAMINATION OF THE ASSOCIATIONS BETWEEN SELECTED PERFLUOROALKYL SUBSTANCES AND THEIR ISOMERS WITH BODY WEIGHT IN ADOLESCENTS USING NHANES 2013-2018 Jessica Snyder, Master of Science, 2023 Thesis Directed by: Professor Devon Payne-Sturges Maryland Institute for Applied Environmental Health Perfluoroalkyl substances (PFAS), a class of environmentally persistent chemicals, are suspected of having obesogenic properties, with studies thus far being inconclusive. Few past studies of PFAS toxicity have distinguished between isomer types of each PFAS group during analysis, however. In this thesis, data for non-smoking 14-19 year-olds from three cycles of the National Health and Nutrition Examination Survey was analyzed to identify potential associations in adolescents between bodyweight and two major families of PFAS: perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) and to additionally determine if differentiating between linear and branched isomeric groups of two major PFAS families could better elucidate any associations found. In unadjusted models, weighted linear regression of body mass index (BMI) and serum concentrations of branched, linear, and total PFAS isomer groups, all returned positive associations ranging from β (95% confidence interval) of 4.06 (3.44, 4.68) for total PFOS to 12.33 (10.39,14.28) for linear PFOA. When models were adjusted for sex, age, race/ethnic origin and income level, however, only a negative association between BMI and branched PFOS (bPFOS) was found, with β= -1.24 (-2.10, -0.39). Unadjusted weighted logistic regression models of both overweight and obese status resulted in positive associations between obesity and both branched PFOS and total PFOS with odds ratios (95% confidence intervals) of 0.45 (0.27, 0.74) and 0.86 (0.75, 0.99) respectively. After adjusting for potential confounders, the only statistically significant relationship was between branched bPFOS and obesity, with a 56% decrease in the odds of obesity for every unit increase in serum concentration of bPFOS [β =-1.06, adjusted odds ratio= 0.44 (0.26,0.76)]. There was no significant difference between the sexes in any results. The apparent protective effect that bPFOS has against obesity and elevated BMI, notable as a health outcome association in itself, also illustrates that isomeric differentiation is important in studying PFAS, as nPFOS had no statistically significant 1 association by itself while ΣPFOS, used by many studies, did. Thus, the lack of differentiation could mask which PFAS type contributes to any associations discovered.Item Adolescents' Attitudes Toward the Economic and Societal Responsibilities of Government in 24 Countries(2019) White, Gregory; Kahn, Joan; Sociology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Adolescents’ attitudes toward government responsibilities for economic and societal well-being are examined in 24 countries grouped within welfare regime types. Adolescents’ own sense of civic responsibility to participate in community service is also investigated. This study uses data from the IEA Civic Education Study (1999) in combination with macroeconomic indicator data employing descriptive statistics, multiple regression, and other techniques to compare results between regimes and countries. The adolescents surveyed in 1999 are now adult members of a millennial generation that is rising in political influence. Adolescents demonstrate well-established attitudes that are consistent with those of adults in certain welfare regime contexts. Attitudes toward economy-related government responsibilities are in the expected directions for regimes with a legacy of communism, which are above the international mean, as well as in the liberal regime, which is below the international mean. Adolescents in the United States (a liberal regime ideal-type country) hold the least favorable attitudes toward government-provided economic support. In addition, adolescents’ expectations of community participation are higher in the liberal and Southern Europe regimes. Female students are more likely to believe in government provision for economic needs in liberal, Southern Europe, and post-communist Central Europe regimes. Notably, no significant gender differences are found in the social democratic regime, where women face fewer social protection risks. Female students are also much more likely than males to anticipate future volunteer community participation across regimes. Contrary to expectations, variables measuring social class have few significant or meaningful associations. Volunteering has small negative effects with belief in government-provided economic support in most regimes, and small to moderate positive effects with adolescents’ anticipated community engagement in all regimes. In addition, studying community problems has small positive effects with support for economy-related government responsibilities in several regimes (including liberal) and small to moderate positive effects in all regimes for anticipated community engagement. Finally, collective student efficacy and support for ethnic minority group opportunities have positive associations with beliefs that both governments and individuals are responsible for economic and societal needs.Item Relation between Adolescent Callous-unemotional Traits and Subjective and Physiological Reactions to Social Exclusion(2017) Augenstein, Tara M; De Los Reyes, Andres; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Callous-unemotional (CU) traits (e.g., lack of empathy and guilt toward others) occur dimensionally, across the age range, and in both clinical and nonclinical populations. Among adolescents with co-occurring conduct problems, elevated CU traits are linked to multiple negative outcomes. Yet, little is known about the potential negative or positive impact of CU traits among adolescents at low-risk for displaying conduct problems. Prior research suggests the unique constellation of cognitive, emotional, and biological characteristics associated with CU traits may buffer adolescents’ negative emotional reactions to distressing social situations. In the current study, I tested this idea by examining whether the severity of CU traits impacted adolescents’ experience as victims of a negative social interaction, namely social exclusion. Specifically, I examined the impact of CU traits on adolescents’ self-reported distress following social exclusion, and physiological arousal during exclusion. Participants included a mixed community-based and clinical sample of 86 adolescent-parent dyads. Dyads completed measures of adolescent social anxiety and CU traits. Next, adolescents completed a computerized social exclusion task during which I collected measures of adolescent physiological arousal (e.g., heart rate). Adolescents then completed a subjective distress scale to assess mood and distress following the social exclusion task. Adolescent males and those with clinically elevated levels of social anxiety displayed significantly higher CU traits relative to females or those without clinically elevated levels of social anxiety. Surprisingly, adolescent CU traits were not significantly related to differences in self-reported distress following exclusion. Adolescents’ physiological arousal varied throughout the social exclusion task, with adolescents experiencing increased arousal transitioning from social inclusion to social exclusion, and heightened arousal persisting through the remainder of the task. Adolescent gender and CU trait severity significantly predicted overall physiological arousal during the social exclusion task. Specifically, as CU trait severity increased, adolescent males displayed decreased physiological arousal, whereas no differences in arousal were observed for adolescent females, regardless of CU trait severity. These findings suggest that among male adolescents at low risk for conduct problems, elevated CU traits may serve to buffer negative emotional reactions to aversive social situations.Item Embracing mathematics identity in an African-centered school: Construction and interaction of racial and mathematical student identities(2010) Nyamekye, Farhaana; Chazan, Daniel; Curriculum and Instruction; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)ABSTRACT Title of Document: EMBRACING MATHEMATICS IDENTITY IN AN AFRICAN-CENTERED SCHOOL: CONSTRUCTION AND INTERACTION OF RACIAL AND MATHEMATICAL STUDENT IDENTITIES Farhaana Nyamekye, Ph.D, 2010 Directed By: Associate Professor of Mathematics Education, Daniel Chazan, Curriculum and Instruction This dissertation is a report of a multiple case study of eight seventh grade African American students attending an African-centered school. This African-centered school is attended solely by children of African descent and adheres to a system of African cultural values, focusing on culture, relationships, and academic excellence. The report provides in depth case analyses of two of these students as they navigate their multiple identities. The foci of the analyses are on the students' construction of their math learner identities and racial identities and on their construction of both of these identities taken together. Phenomenological variant of ecological systems theory illuminates the challenges and supports that these students encounter in constructing their identities. The mathematics and racial socialization practices within the school and within the students' home environments are documented within this report as support mechanisms that provide opportunities for the students to construct identities as African American mathematics learners. The findings suggest that academic spaces that reduce the stress of racism and help students to value their racial identity may be particularly important spaces for other African American mathematics learners. The findings also have positive implications for the implementation of African and African American cultural practices and programs that can help other African American learners to positively construct identities as both African Americans and math learners. The documented findings raise critical questions about whether other African American learners that share the historical legacy of enslavement with the students in this study would benefit from African-centered schooling, despite the heterogeneity within this population.Item The Challenge of Teen Nutrition: An Ecological View of Sociocognitive Influences on Urban, African-American Adolescent Diet Quality(2010) Wrobleski, Margaret Mary; Atkinson, Nancy L.; Public and Community Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The routine food choices that adolescents make impact their nutritional status, health, and their risk of developing chronic illnesses such as heart disease, cancer, and osteoporosis in the future. Nutrient requirements during adolescence are comparable to those in early infancy, emphasizing the importance of a high quality diet for healthy growth and development. A myriad of personal, social, and environmental factors influence adolescents in shaping their dietary intake and quality of diet. Low-income, African-American adolescents in Baltimore were identified as having sub-optimal nutritional intake compared to national dietary recommendations. This study explored the dynamic and relative contributions that factors within three environmental levels (personal, social, and community) made as predictors of diet quality in a sample of low-income, urban African-American adolescents using an integrated Social Cognitive Theory (SCT) / ecological theoretical framework. It was hypothesized that 1) the personal, social, and community environmental levels of dietary influences would all significantly contribute to diet quality, with community environment making the largest relative contribution; 2) self-efficacy for healthy eating moderated the relationship between parental beliefs about nutrition and diet quality; and 3) self-efficacy for healthy eating moderated the relationship between peer eating behaviors and diet quality. There have been very few studies using an integrated SCT/ecological model to explore the dietary influences on adolescent nutrition, especially on this demographic. The significant influence the SCT construct of observational learning has on adolescents was evidenced in this study by the positive relationship found between diet quality, parental beliefs about nutrition, and peer eating behavior. Younger participants in early adolescence and females were predominately guided by their parents' beliefs about nutrition, while males in this study appeared to identify more with their peers' nutrition-related behaviors. This study revealed that parents and peers play important roles in African-American adolescents' food choices and subsequent diet quality. Nutrition interventions should focus on parent-teen interactions and on improving the dietary habits of parents so they may be more effective role models for youth. Nutrition promotion research targeting young African-American men may consider using group interactive behavioral interventions with peers that build and reinforce peer modeling of positive nutrition behaviors.Item Family Processes and Leisure Activity Involvement Across the High School Transition: The Mediating Roles of Adolescent Internalizing Problems and Self-Esteem(2010) Dashiell-Aje, Ebony N.; Rubin, Kenneth H; Human Development; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Parents are among the most important socializing agents in adolescents' lives. The purpose of the current study was to examine the prospective relations between family processes and leisure activity involvement across the high school transition. Specifically, I explored the meditational role of adolescent psychological well-being (internalizing problems and self-esteem) in these relations. The first aim of the present study included two dimensions: 1) to examine whether there were prospective relations between family processes (maternal and paternal parenting) and adolescent leisure involvement across the high school transition; and 2) to investigate the extent to which psychological well-being mediated the relations between family processes and adolescent leisure activity choices, based on Eccles and Harold's (1991) research linking parenting dimensions to leisure outcomes. The second aim of this study was to explore whether boys and girls differed in the extent to which their psychological well-being mediated the relations between family processes and leisure activity involvement from the 8th to the 9th grade. It was hypothesized that perceptions of maternal and paternal parenting would differentially relate to adolescent leisure activity intensity and enjoyment. Likewise, I hypothesized that internalizing problems and self-esteem would act as mediators in these relations. Finally, I hypothesized that gender would moderate some of the meditational relations. OLS regression and bootstrapping techniques were used to test simple mediation and moderated mediation for all variables. Significant mediation effects emerged for relations between perceptions of paternal involvement and sports intensity and enjoyment through internalizing problems. Additionally, internalizing problems mediated the relation between perceptions of paternal support and sports enjoyment. An indirect effect emerged for the relation between adolescent's perceptions of maternal negativity and arts enjoyment through self-esteem. Subsequent hierarchical regressions revealed significant gender by family process interactions when predicting leisure involvement and one significant gender by internalizing problems interaction effect emerged when predicting social activity enjoyment. These findings suggest that maternal and paternal parenting play significant and differential roles in adolescent leisure activity involvement across the high school transition. These results also suggest that adolescent psychological well-being effects the relations between adolescent perceptions of parenting and their leisure activity involvement.Item Maternal Adolescent Parenting Behavior and Child Aggressive and Inattentive Behavior: Findings from the Early Head Start Research and Evaluation Project(2008-11-17) Guner, Bella Mironovna; Klein, Elisa L; Jones Harden, Brenda; Human Development; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Adolescent parenting is associated with a wide variety of risk factors for both the mother (Berlin, Brady-Smith, & Brooks-Gunn, 2002) and child (Moore & Brooks-Gunn, 2002). Understanding the pathways leading toward poor parenting practices, and the subsequent influences on child aggressive and inattentive behavior may yield important information for intervention efforts on the part of adolescent families. The current study examines which maternal characteristics influence parenting behavior in a high risk sample of adolescent mothers and their toddlers, using Belsky's (1984) parenting process model. The purpose of the study was to: 1) examine whether maternal age, depression, or stress influenced positive and negative parenting behavior, 2) examine the influence of positive and negative parenting behavior on child aggressive and inattentive behavior, and 3) examine whether positive parenting would mediate the association between maternal characteristics and child aggressive and inattentive behavior. Data from the Early Head Start Research and Evaluation dataset was used to examine the aforementioned questions. The sample consisted of 319 mothers ages 15-19 and their toddlers ages 2-3 years. Heirarchical regression analyses revealed that maternal depression predicted higher levels of negative parenting behavior, younger adolescent mothers are more likely to engage in punitive parenting behavior than older adolescents, and maternal stress predicted lower levels of positive and higher levels of negative parenting behavior. Logistic regression analyses revealed that adolescent mothers who engaged in positive parenting behavior were less likely to have children who engaged in aggressive and inattentive behavior, and parents who engaged in negative parenting behavior were more likely to have children who engaged in aggressive and inattentive behavior. Mediational analyses revealed that positive parenting behavior mediated the association between maternal stress and child aggressive and inattentive behavior. These findings suggest that maternal characteristics are an important factor to consider in parenting behavior, and that despite the difficulties faced by adolescent mothers, there is room for positive parenting, which may mitigate the influence of maternal stress. The findings from this study indicate that intervention efforts may benefit from focusing on teaching adolescent mothers how to engage in positive parenting behaviors with their toddlers, thereby reducing the risk for future child aggressive and inattentive behaviors.Item Body images in magazines: A cross-cultural investigation of media effects in Russian and U.S. young women(2007-04-25) Markova, Svetlana V.; McAdams, Katherine C.; Journalism; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The dissertation is a cross-cultural-generational investigation of audiences' perceptions of media messages. The study comparatively examines adolescent and young adult females' concepts of body images in beauty and fashion magazines in Russia and USA. The theoretical model for the study was developed in the intersection of mass communication and human development research traditions. Specifically, media effects and audience research traditions of media studies, in combination with social-cognitive domain theory of developmental psychology, were applied for analysis of direct and indirect impact of media messages on young women; of their motivations for reading magazines; of their critical evaluations of media content; and of their predispositions to media-associated health risks. The study was conducted in two stages: mixed research methodologies employing qualitative exploration of the stated problem followed by its quantitative examination. A total of 20 participants (10 Russian and 10 U.S. teenage females) were recruited for in-depth interviews; this part of the study focused primarily on differences in media uses and perceptions between adolescent audiences across cultures. The hypotheses and the survey questionnaire for the second part of the study were developed on the basis of these qualitative data and used to test both cultural and generational differences among media audiences. A total of 400 survey participants represented adolescent (mean age=18.5) and young adult (mean age=28) females in Russia and USA. Two major factors were found to be significant in determining perceptions of media messages by diverse audiences: (1) desire for advice about body-related issues and (2) desire for information and entertainment. Adolescent females were more motivated to read magazines for entertainment and informational purposes than adult women in both cultures, whereas U.S. females were more motivated by body-awareness than Russian females in both generational cohorts. In this connection, U.S. females experienced lower levels of self-esteem after reading magazines and were more predisposed to development of eating disorders than Russian females. The study revealed limited effects of media on diverse cultural and generational audiences, suggesting that media users select specific media content and are consequently influenced by it based on personal motivations for reading specific content of their interest.