Barrett, The Honors College Thesis/Creative Project Collection
Barrett, The Honors College at Arizona State University proudly showcases the work of undergraduate honors students by sharing this collection exclusively with the ASU community.
Barrett accepts high performing, academically engaged undergraduate students and works with them in collaboration with all of the other academic units at Arizona State University. All Barrett students complete a thesis or creative project which is an opportunity to explore an intellectual interest and produce an original piece of scholarly research. The thesis or creative project is supervised and defended in front of a faculty committee. Students are able to engage with professors who are nationally recognized in their fields and committed to working with honors students. Completing a Barrett thesis or creative project is an opportunity for undergraduate honors students to contribute to the ASU academic community in a meaningful way.
Displaying 1 - 10 of 36
Description
Due to artificial selection, dogs have high levels of phenotypic diversity, yet, there appears to be low genetic diversity within individual breeds. Through their domestication from wolves, dogs have gone through a series of population bottlenecks, which has resulted in a reduction in genetic diversity, with a large amount of linkage disequilibrium and the persistence of deleterious mutations. This has led to an increased susceptibility to a multitude of diseases, including cancer. To study the effects of artificial selection and life history characteristics on the risk of cancer mortality, we collected cancer mortality data from four studies as well as the percent of heterozygosity, body size, lifespan and breed group for 201 dog breeds. We also collected specific types of cancer breeds were susceptible to and compared the dog cancer mortality patterns to the patterns observed in other mammals. We found a relationship between cancer mortality rate and heterozygosity, body size, lifespan as well as breed group. Higher levels of heterozygosity were also associated with longer lifespan. These results indicate larger breeds, such as Irish Water Spaniels, Flat-coated Retrievers and Bernese Mountain Dogs, are more susceptible to cancer, with lower heterozygosity and lifespan. These breeds are also more susceptible to sarcomas, as opposed to carcinomas in smaller breeds, such as Miniature Pinschers, Chihuahuas, and Pekingese. Other mammals show that larger and long-lived animals have decreased cancer mortality, however, within dog breeds, the opposite relationship is observed. These relationships could be due to the trade-off between cellular maintenance and growing fast and large, with higher expression of growth factors, such as IGF-1. This study further demonstrates the relationships between cancer mortality, heterozygosity, and life history traits and exhibits dogs as an important model organism for understanding the relationship between genetics and health.
ContributorsBalsley, Cassandra Sierra (Author) / Maley, Carlo (Thesis director) / Wynne, Clive (Committee member) / Tollis, Marc (Committee member) / School of Life Sciences (Contributor) / School of Human Evolution and Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
The transition from high school to college is associated with considerable life strain for adolescents, including higher reported levels of daily stress and negative affect (NA), and alterations in stress physiology have been linked to poor health. The purpose of this thesis was to use an ecological momentary assessment design to study associations between momentary experiences of negative affect and cortisol levels in a sample of adolescents transitioning to college. I also examined the potential moderating effects of two potential vulnerability or protective factors, alone status and perceived social support from friends. Adolescents provided salivary samples and completed paper-and-pencil diary reports of socioemotional experiences and alone status five times per day for three consecutive weekdays, as well as completed self-report questionnaires on perceived social support from friends. Within-person increases in momentary negative affect were associated with momentary cortisol reactivity. Alone status significantly moderated this association such that the association between momentary negative affect and momentary cortisol levels was only significant when individuals were with others and not when they were alone. Perceived social support from friends did not significantly moderate the within-person associations between negative affect and momentary cortisol levels. The findings add to our understanding of physiological correlates of socioemotional experiences, as well as contexts in which these associations may be exaggerated or attenuated. The findings inform our understanding of potential pathways by which physiological reactivity to socioemotional experiences may affect the health of adolescents as well as how prevention efforts could reduce potential poor health outcomes associated with heightened stress reactivity.
ContributorsKomarnisky, Sydney-Paige Milan (Author) / Doane, Leah (Thesis director) / Knight, George (Committee member) / Luecken, Linda (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / Department of Psychology (Contributor)
Created2014-12
Description
Cancer is a disease that occurs in many and perhaps all multicellular organisms. Current research is looking at how different life history characteristics among species could influence cancer rates. Because somatic maintenance is an important component of a species' life history, we hypothesize the same ecological forces shaping the life history of a species should also determine its cancer susceptibility. By looking at varying life histories, potential evolutionary trends could be used to explain differing cancer rates. Life history theory could be an important framework for understanding cancer vulnerabilities with different trade-offs between life history traits and cancer defenses. Birds have diverse life history strategies that could explain differences in cancer suppression. Peto's paradox is the observation that cancer rates do not typically increase with body size and longevity despite an increased number of cell divisions over the animal's lifetime that ought to be carcinogenic. Here we show how Peto’s paradox is negatively correlated for cancer within the clade, Aves. That is, larger, long-lived birds get more cancer than smaller, short-lived birds (p=0.0001; r2= 0.024). Sexual dimorphism in both plumage color and size differ among Aves species. We hypothesized that this could lead to a difference in cancer rates due to the amount of time and energy sexual dimorphism takes away from somatic maintenance. We tested for an association between a variety of life history traits and cancer, including reproductive potential, growth rate, incubation, mating systems, and sexual dimorphism in both color and size. We found male birds get less cancer than female birds (9.8% vs. 11.1%, p=0.0058).
ContributorsDolan, Jordyn Nicole (Author) / Maley, Carlo (Thesis director) / Harris, Valerie (Committee member) / Boddy, Amy (Committee member) / School of Molecular Sciences (Contributor) / Department of Psychology (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Cancer rates in our nearest relatives are largely unknown. Comparison of human cancer rates with other primates should help us to understand the nature of our susceptibilities to cancer. Data from deceased primates was gathered from 3 institutions, the Duke Lemur Center, San Diego Zoo, and Jungle Friends primate sanctuary. This data contained over 400 unique individuals across 45 species with information on cancer incidence and mortality. Cancer incidence ranged from 0-71% and cancer mortality ranged from 0-67%. We used weighted phylogenetic regressions to test for an association between life history variables (specifically body mass and lifespan) and cancer incidence as well as mortality. Cancer incidence did not correlate with both body mass and lifespan (p>.05) however, cancer mortality did (p<.05). However, it is uncertain if the variables can be used as reliable predictors of cancer, because the data come from different organizations. This analysis presents cancer incidence rates and cancer mortality rates in species where it was previously unknown, and in some primate species, is surprisingly high. Microcebus murinus(grey mouse lemur) appear to be particularly vulnerable to cancer, mostly lymphomas. Further studies will be required to determine the causes of these vulnerabilities.
ContributorsWalker, William Charles (Author) / Maley, Carlo (Thesis director) / Boddy, Amy (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Bats (order Chiroptera) are the longest lived mammals for their size, with particularly extreme longevity evolving in the family Vespertilionidae, or vesper bats. Because of this, researchers have proposed using bats to study ageing and cancer suppression. Here, we study gene duplications across mammalian genomes and show that, similar to previous findings in elephants, bats have experienced duplications of the tumor suppressor gene TP53, including five genomic copies in the genome of the little brown bat (Myotis lucifugus) and two copies in Brandt's bat (Myotis brandtii). These species can live 37 and 41 years, respectively, despite having an adult body mass of only ~7 grams. We use evolutionary genetics and next generation sequencing approaches to show that positive selection has acted on the TP53 locus across bats, and two recently duplicated TP53 gene copies in the little brown bat are both highly conserved and expressed, suggesting they are functional. We also report an extraordinary genomic copy number expansion of the tumor suppressor gene FBXO31 in the common ancestor of vesper bats which accelerated in the Myotis lineage, leading to 34\u201457 copies and the expression of 20 functional FBXO31 homologs in Brandt's bat. As FBXO31 directs the degradation of MDM2, which is a negative regulator of TP53, we suggest that increased expression of both FBXO31 and TP53 may be related to an enhanced DNA-damage response to genotoxic stress brought on by long lifespans and rapid metabolic rates in bats.
ContributorsSchneider-Utaka, Aika Kunigunda (Author) / Maley, Carlo (Thesis director) / Wilson Sayres, Melissa (Committee member) / Tollis, Marc (Committee member) / School of Life Sciences (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
Research has shown that environmental stressors that occur during childhood and early adolescence are associated with multiple deficits in physiological and psychological functioning later in life. The hypothalamic-pituitary-adrenal (HPA) axis has been proposed as a potential biological mechanism through which these phenotypic alterations occur as studies have shown a link between early life adversity and altered diurnal cortisol patterns (Goldman-Mellor, Hamer, & Steptoe, 2012; Gunnar & Quevedo, 2008). Given research has shown that diurnal cortisol levels are influenced by genetic factors (Veen et al., 2011), but that a majority of differences across subjects can be attributed to the environment (Schreiber et al., 2006), phenotypic associations were explored between the quality of the home environment and children's diurnal cortisol patterns. The first aim of this study was to determine the level of genetic and environmental contributions to different parameters of diurnal cortisol rhythm. The second aim of this study was to examine whether the quality of the home environment, particularly indicators involving parenting and the physical environment, was associated with these same diurnal cortisol measures. A diverse sample of 320 twin children were assessed at 8 years using gold standard home environment interviews and a measure of diurnal cortisol rhythm across three days with three samples taken from each twin every day. Twin intraclass correlations indicated high levels of heritability for the morning to afternoon diurnal cortisol slope as well as the afternoon to evening slope, while measures of cortisol in the afternoon, evening, and across the day showed low levels of heritability, which suggested that differences in the environment were a more influential factor. Multilevel regression analyses showed that the overall quality of the home environment was found to be significantly negatively associated with cortisol levels at bedtime and negatively associated across the morning to afternoon slope at a trend level. The physical environment and emotional climate of the home were not significantly associated with any indicators of the diurnal cortisol pattern. A unique seasonality effect was noted as cortisol measurements taken from participants during the summer were significantly increased when compared to participants throughout the rest of the year. Overall, these findings showed a unique association between the quality of the home environment and diurnal cortisol levels at bedtime and perhaps the change in cortisol levels across the morning to afternoon, as well as a possible seasonal covariate which may affect diurnal cortisol measurements and one which often goes overlooked in cortisol research.
ContributorsSmith, Trevor James (Author) / Doane, Leah (Thesis director) / Lemery-Chalfant, Kathryn (Committee member) / School of Molecular Sciences (Contributor) / Arizona State University. College of Nursing & Healthcare Innovation (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Cultural beliefs and behaviors can serve as both risk and protective processes for Latino adolescents, with some recent empirical work suggesting the important protective role of bicultural values (e.g., endorsing high levels of both mainstream culture and culture of origin). We expanded on past research to explore whether bicultural values were associated with internalizing (depressive, anxiety, stress) symptoms and externalizing (alcohol use) symptoms among a sample of Latino adolescents preparing to begin college. We hypothesized biculturalism to protect against all negative outcomes. Our sample consisted of 209 college-bound Latino adolescents (65% female; 85.1% Mexican descent; 10.6% 1st generation, 62% 2nd generation) who were enrolled in university for the coming fall. All multivariate models included sex, ethnicity, parent education, and immigrant generation status as covariates. Correlations and multivariate analyses revealed that higher bicultural values were associated with lower depressive symptoms, lower anxiety symptoms, lower stress, and greater alcohol use. Gender was shown to moderate the relationship between biculturalism and alcohol use. Overall, findings suggested that greater bicultural values were associated with lower endorsement of internalizing symptoms for all participants, but higher endorsement of alcohol use over the last year for the highly bicultural females. Biculturalism may be particularly protective for Latino adolescents who are preparing to attend college given the need for them to transition into an environment with high acculturative demands. However, our results also highlight that these bicultural females may be at greater risk for alcohol use and related problems.
ContributorsDilgert, Janice (Author) / Doane, Leah (Thesis director) / Thompson, Daisy (Committee member) / Department of Psychology (Contributor) / School of Nutrition and Health Promotion (Contributor) / Barrett, The Honors College (Contributor)
Created2017-12
Description
The objective of the current study was to examine sleep and academic functioning during middle childhood. More specifically, the twin design was used to determine the heritability of academic competence and sleep. Phenotypic analyses using multi-level mixed model regressions were performed to predict academic functioning from sleep. Lastly, socioeconomic status was tested as a moderator in the associations between sleep and academic functioning. Participants included twins (N = 191 families; Mage = 8.47 years) recruited from Arizona birth records at 12 months of age. Sleep duration, latency, onset, efficiency, variability, and sleep problems were assessed using actigraph watches and the Child Sleep Habits Questionnaire. Academic functioning was assessed using subtests of the Woodcock Johnson Cognitive Test of Achievement-IV (picture vocabulary, passage comprehension, and applied problems) and the MacArthur Health and Behavior Questionnaire. As determined by twin intraclass correlations, the heritability of academic competence ranged from 51-76%. Sleep heritability ranged from 14-80%. In addition, phenotypic analyses only showed a significant association between sleep latency and WJ picture vocabulary scores. More specifically, sleep latency was negatively associated with the picture vocabulary subtest. Additional models were run to examine if any interactive effects were present between early SES and the various sleep parameters. Several significant associations were observed with applied problems scores and parent-reported academic competence. Specifically, for children of low SES, a significant positive association was observed for sleep duration and WJ applied problems scores, as well as for sleep efficiency and WJ applied problems scores. No significant associations were observed for sleep efficiency and HBQ scores with children of any SES. Also, no significant relationships were observed with children of high SES for any of the academic measures.
ContributorsVakulskas, Emily (Author) / Doane, Leah (Thesis director) / Lemery-Chalfant, Kathryn (Committee member) / Breitenstein, Reagan (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Higher education institutions have increasingly sought to diversify the ethnic makeup of freshmen classes (Covarrubias, Herrmann, & Fryberg, 2016) and rates of Latinx college attendance have been rising (Hall, Nishina, & Lewis, 2017). However, despite comparable levels of earned-credits, Latinx students have lower rates of college completion (Contreras & Contreras, 2015). One potential explanation may be disproportionate increases in stress, and in particular, discrimination experiences reported by Latinx students during the transition from high school to college (Hunyh & Fuligni, 2012). As such, the aim of the current study was to examine whether everyday discrimination in high school and college were associated with changes in adolescent well-being and academic adjustment over the college transition in a sample of Latinx adolescents. Study participants were 209 Latinx adolescents (85.1% Mexican descent, 62.1% 2nd generation; 35.6% male; Mage= 17.59) who completed questionnaire assessments during the spring or summer before entering college (T1) and again during the first semester of college (T2; 88.5% retention). In both high school and college, participants completed a modified version of the Everyday Discrimination Scale (T1 α=.88, T2 α=.89; Williams et al., 1997). Dependent variables included internalizing symptoms in college (depressive symptoms {α = .95}, anxiety symptoms {α = .88}, stress symptoms {α = .94}; DASS; Lovibond & Lovibond, 1995), and institutional records of college GPA. Correlation and regression analyses were conducted in SPSS 23 to examine associations between discrimination experiences (high school and college) and college internalizing symptoms and GPA, controlling for high school levels. Other covariates included immigrant generation status, sex, parent education (as a proxy for socioeconomic status), and whether the participant attended the focal higher education institution. Zero order correlations (Table 1) revealed that greater reports of discrimination in high school and college were associated with higher depressive symptoms, higher anxiety symptoms, higher stress, but not GPA in college (Table 1; all ps <.05). In multivariate analyses and after adjusting for covariates similar patterns emerged (Table 2). Greater reports of discrimination in college were associated with higher depressive symptoms (β = .18, p < .05), anxiety symptoms (β = .19, p <.05) and stress (β = .18, p <.05), but not GPA (β = -.04, ns). Everyday experiences of discrimination in high school were not significantly associated with college outcomes. In summary, our findings suggest that discrimination experiences among Latinx students in college, but not high school, are associated with increases in internalizing symptoms, including depression, anxiety and stress. Interestingly, discrimination experiences in high school and college were not associated with academic achievement in the first semester of college. Such findings suggest that higher education institutions should focus on global indicators of well-being during the Latinx college transition and seek to implement programs to: a) reduce stress associated with engaging in diverse college environments and b) reduce discrimination experiences on college campuses. Future research is needed for replication of these results and should also seek to further explore the trajectories of internalizing symptoms beyond the first semester of college.
ContributorsSills, Jessica (Author) / Doane, Leah (Thesis director) / Perez, Marisol (Committee member) / Castro, Saul (Committee member) / Department of English (Contributor, Contributor) / Department of Psychology (Contributor) / Sanford School of Social and Family Dynamics (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Nucleic acid polymers have numerous applications in both therapeutics and research to control gene expression and bind biologically relevant targets. However, due to poor biological stability their clinical applications are limited. Chemical modifications can improve both intracellular and extracellular stability and enhance resistance to nuclease degradation. To identify a potential candidate for a highly stable synthetic nucleic acid, the biostability of α-L-threofuranosyl nucleic acid (TNA) was evaluated under simulated biological conditions. TNA contains a four-carbon sugar and is linked by 2’, 3’ phosphodiester bonds. We hypothesized that this distinct chemical structure would yield greater nuclease resistance in human serum and human liver microsomes, which were selected as biologically relevant nuclease conditions. We found that TNA oligonucleotides remained undigested for 7 days in these conditions. In addition, TNA/DNA heteropolymers and TNA/RNA oligonucleotide duplexes displayed nuclease resistance, suggesting that TNA has a protective effect over DNA and RNA. In conclusion TNA demonstrates potential as a viable synthetic nucleic acid for use in numerous clinical and therapeutic applications.
ContributorsCulbertson, Michelle Catherine (Author) / Maley, Carlo (Thesis director) / Mangone, Marco (Committee member) / Larsen, Andrew (Committee member) / School of Molecular Sciences (Contributor) / School of International Letters and Cultures (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12