Student Research

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Open Access
Unbinding the Structures of Narrative Agency: Internarrative Subjectivity and the Classical Aesthetic Foundation of Ricoeurean Identity
(University of Oregon, 1997-12) Maan, Ajit K.
While contemporary inquiries into the nature of the "self' are inclined to allow previously marginalized groups to assert their status as subjects and their stories as narratives, the postmodern denial of authorship and deconstruction of the self as a linguistic construction throws this entire inquiry into question. But while deconstruction calls autobiography into question by problematizing the authority and source of any utterance, others point out that the postmodern deconstruction of subjectivity is a luxury of the privileged. As one philosopher puts it, "in order to announce the death of the subject one must have gained the right to speak as one." Paul Ricoeur sees his work as providing a solution to the recent debates concerning the status of the subject. Ricoeur's is a narrative solution. Aristotelian muthos becomes the imaginative technique whereby an otherwise fractured and fluctuating subject constitutes herself. But I argue that this exclusive focus on Aristotelian employment causes a marginalization of narratives based on other constructions of experience. Aristotelian muthos is a process of making the intelligible out of the accidental, the universal from the singular, the necessary from the episodic. But there are different kinds of narrative practice which represents subjectivity that is disjunctive and non-linear. This type of narrative practice is aligned with the postmodern suspicion of identity, and yet it recognizes the imperative for situating an already marginal subject. While canonical Western narratives associate identity with formal integrity, I argue that textual discontinuity results from experienced nonlinearity and that these textual qualities are deliberate strategies to subvert authoritarian modes of self-representation. I propose an alternative to Narrative Identity Theory, a theory I call Internarrative Identity Theory, which involves a more inclusive notion of plot. To unbind classical structure is to maximize agency in determining, and re-determining, who one is in a way that is truly imaginative.
Open Access
The Factors of Placement and Intensity of Emphasis in Learning
(University of Oregon, 1939) Porter, Jr, Elias Hull
One purpose of this thesis will be to clarify the results of previous experimenters in regard to the particular problem investigated and principles discovered. A second purpose of this thesis is to present new experimental evidence and an explanatory hypothesis for the first mentioned problem, that of the relative efficacy of emphasizers which bear information of correctness and which accompany correct or incorrect responses.
Open Access
The Influence of a Period of 'Incidental' Learning Upon Subsequent Learning with Intention
(University of Oregon, 1936-07) Porter, Jr, Elias Hull
Both without and within the formal educational institution a great part of the average person's living experiences are directed in channels other than conscious attempts to gain information. Many of such experiences make use of information which was not consciously or intentionally learned. For example, many items of information may be learned through the reading of novels but it cannot be said that it is always the reader's intention to learn this information. Similarly it may be said that individuals do not always consciously set about learning all of their emotional and attitudinal responses. That such learning does result incidentally in other than conscious learning activities has been shown experimentally, as will be demonstrated in the historical section of this study. Moreover, a given period of such 'incidental' learning has been demonstrated experimentally to be less effective than an equal period of learning in which the intent to learn was present. Since it is easily conceivable that a given situation may be first met under conditions that do not call for intended learning and later under conditions that demand conscious learning activity, it becomes important to know what influence such as an initial period exerts upon subsequent intentional learning. It is the purpose of this study to seek the answer to the question of the influence of a period of 'incidental' learning upon subsequent intentional learning in a series of experimental situations where the materials to be learned consist of meaningless syllables, simple words, complex words, and simple puzzles. The materials to be learned were selected so as to fall into two classifications: (1) memoritor or rote type learning, and (2) learning by problem solving.
Open Access
The Cyclic Realities of Man and Nature in a Palauan Village
(University of Oregon, 1972-09) Klee, Gary Allen
The geographer records interrelationships between man and environment as they affect place, but he often neglects the invisible forces of nature . Too often he has limited his scope to: (1) the elements or things that makeup the landscape; (2) the processes or ways in which the elements in the landscape originated and developed; and (3) t he agents or individuals or groups that activate the processes. But these characterizations do not adequately describe an area that is very much alive. One means of capturing a landscape's dynamic quality is to include in the study a discussion of "cyclic time." This dissertation is an attempt to describe a landscape through "cyclic time"--the diurnal, monthly, and seasonal cycles of man and nature in Ngermetengel, Palau, a small fishing village in Micronesia .
Open Access
Parenting Stress, Acculturative Stress, Depression, and Financial Strain Among Latine Adults in an Emerging Immigrant State
(University of Oregon, 2024-12-19) Romero, Lindsey; McWhirter, Benedict
Heightened anti-immigrant sentiment within recent history in the United States has exacerbated distress among Latine adults, especially by negatively affecting parenting practices and increasing acculturative stressors. Culturally responsive parenting interventions that acknowledge the saliency of acculturative stress among Latine adults present an opportunity to better support and understand mental health outcomes among this underserved population. Using the Family Stress Model and existing data from 241 Latine adults living in an emerging immigrant state, the present study addresses gaps in the literature by: 1) conducting an efficacy study of the parenting intervention Nuestras Familias (Martinez & Eddy, 2005) through an ANCOVA analysis, 2) examining the influence of parenting stress and acculturative stress on depression through hierarchical linear regression, and 3) assessing financial strain as a moderator of the relationship between parenting stress, acculturative stress, and depression through a moderated multiple regression. Implications for intervention and future research are presented.
Open Access
Depression among Multiracial Adults: The Role of Discrimination and Social Support
(University of Oregon, 2024-12-19) Luther, Gabriella; Kelly, Nichole
Although it is unclear whether rates of depression differ for Multiracial individuals compared to Monoracial People of Color (MPOC) and Monoracial White (MW) individuals, Multiracial individuals could be at higher risk secondary to unique experiences with discrimination and social support. Experiencing discrimination is robustly associated with depressive symptoms, whereas social support has been shown to buffer this association in MPOC. Multiracial people often face discrimination from multiple racial groups (i.e., double rejection) and are less likely to receive the protective in-group benefits their monoracial peers report. Simultaneously, Multiracial people have reported increased ability to traverse social boundaries, which could increase their opportunities for social support. The current study examined how the variables of discrimination, social support, and depression differ across Multiracial, MW, and MPOC. The link between discrimination and depression was evaluated among Multiracial participants. Sources of social support were examined as moderators. Multiple regression analyses conducted among the full sample (N = 1,322, Mage = 40.6 ± 20.5), showed that discrimination did not differ by racial group (p = .54). Social support (p < .001, p = .002), peer support (p = .002, p =.02), and family support (p = .02, p < .001) were higher for MW participants than for MPOC and Multiracial people. Depressive symptom were higher for Multiracial participants than for MPOC participants (p < .001). Among Multiracial participants, discrimination was positively associated with depressive symptoms (p < .001). Overall social support (p < .001), peer support (p =.01), and family support (p = .02) were also negatively associated with depressive symptoms, but were not significant moderators. Results suggest that Multiracial people experience higher depressive symptoms than their MPOC counterparts, and discrimination may be a contributor to these experiences. Future research should include measures better designed to capture the experiences of Multiracial adults in an effort to clarify the validity of the double rejection phenomenon. Interventions to reduce the perpetration of monoracism are needed, as are those to help Multiracial people cope with the depressive symptoms associated with these experiences.
Open Access
Social Anxiety and College Drinking Risk: Exploring the Moderating Effect of Experiential Avoidance
(University of Oregon, 2024-12-19) Marchetti, Mary; Cronce, Jessica
Higher levels of social anxiety predict greater incidence of alcohol-related consequences among college students, yet little is known about for whom social anxiety may pose the greatest risk of experiencing alcohol-related consequences and the significance and direction of association between social anxiety and alcohol use remain unclear. This investigation aims to help elucidate the relationships between social anxiety and both alcohol consequences and use by examining experiential avoidance, or a tendency to suppress unwanted internal experiences, as a potential moderator of different aspects of the social anxiety–alcohol link. The current study utilizes data from the Healthy Minds Study, a national survey of college student mental health, which was collected across 79 U.S. colleges during the 2018-2019 academic year. Respondents who were (a) aged 18–30 years old and (b) given the opportunity to complete all key measures included for present analysis comprised the final sample (N = 1,584). A series of regression models using Hayes conditional process analysis were conducted to test experiential avoidance as a moderator of the relationship between social anxiety and alcohol-related consequences and a moderator of the relationship between social anxiety and heavy episodic drinking. Findings revealed a significant, positive association between social anxiety and alcohol-related consequences, while social anxiety was not significantly related to alcohol use. Experiential avoidance was positively linked to both alcohol-related consequences and alcohol use but did not moderate the associations between social anxiety and either outcome. Overall, findings suggest that higher levels of social anxiety may potentially increase risk for alcohol-related consequences but not for alcohol use among a sample of young adult college students, and that experiential avoidance may not modify the strength of either prospective relationship. This investigation paves the way for future explorations into the role of experiential avoidance in the social anxiety–alcohol link and offers insight relevant to the enhancement of preventive intervention efforts to reduce the burden of alcohol-related risk among socially anxious college students.
Open Access
Examining Group Differences in Health and Depression among Sexual and Gender Diverse Individuals: An Intersectional Approach
(University of Oregon, 2024-12-19) Folger, Austin; Kelly, Nichole
Sexual and gender diverse (SGD) individuals experience significant health disparities; yet, little is known about the unique risks of the individuals within this diverse community, particularly at the intersection of sexual, gender, racial, and ethnic identities. The present study aimed to examine differences in depression, suicidal ideation, and chronic health conditions (CHCs) at the intersection of SGD and ethnic and racial identities. Qualtrics Panels recruited 1329 U.S. adults from various SGD subgroups (389 cisgender heterosexual, 289 cisgender bisexual, 219 cisgender gay, 157 cisgender lesbian, and 275 cisgender gender diverse adults) and racial and ethnic subgroups (415 non-Hispanic White, 387 Hispanic or Latinx, 268 Black or African American, 252 Multiracial adults). Participants completed online surveys. After adjusting for income, education, and age, SGD adults had higher depressive symptoms and were more likely to experience suicidal ideation frequently and have CHCs compared to non-SGD adults (ps < .05). There were important variations within SGD and racial and ethnic subgroups suggesting that bisexual, gender diverse, and multiracial adults experience worse mental and/or physical health compared to cisgender, heterosexual respondents. The study findings and extant research underscore the need to examine how health disparity risk varies across SGD subgroups as certain groups may be at greater risk and these risks may vary based on the outcome being examined. There also appears to be a complicated interaction between SGD status, race, and ethnicity. Future research elucidating risk for health disparities should take an intersectional approach to more effectively direct research and intervention.
Open Access
Using Recast Theory to Examine the Racial Stress Appraisal Process Across High Schools: Differences in Racial Threat and Support Appraisals
(University of Oregon, 2024-12-19) Fleming, Maureen; McWhirter, Benedict
The current study utilizes the Racial Encounter Coping Appraisal and Socialization Theory (RECAST) to examine Racial Stress Appraisal (RSA) and Racial Coping Self-Efficacy (RCSE) in youth. This study adds to current understanding of what contributes to the development of RSA and RCSE skills in an effort to support interventions aimed at increasing these capabilities. Data from 301 diverse high school students from three different high schools in the United States was collected through the Racial Empowerment Collaborative research and training center at the University of Pennsylvania. In this study we validated a measure of RSA and RCSE, gleaning factors from each. We then examined if student participants, based on the type of school they attend, varied in their RCSE, RSA, and factor levels. RSA factors included Racial Threat Appraisal and Racial Support Appraisal. Students from the majority White, high socioeconomic status (SES) school reported significantly lower Racial Threat Appraisal and significantly higher Racial Support Appraisal levels than students from the schools with more students of color and greater variability in SES. These results demonstrate how support, racial coping, and stress management skills may help mitigate ongoing interpersonal harm caused by racially stressful experiences among youth. Implications for intervention implementation and future research are discussed.
Open Access
Leptons as a Window to Dark Matter
(University of Oregon, 2024-12-19) Radick, Aria; Cohen, Tim
There is a huge amount of evidence the dark matter exists, however we still do not know what kind of particle it is. Many experiments have been performed to test different models for dark matter, but its nature still remains elusive. In this work we study two different ways of looking for dark matter by using leptons. First, we look at low threshold experiments in the form of dark matter-electron scattering. We know that the rate of dark matter-electron scattering depends on the underlying velocity distribution of the dark matter halo. In particular, dark matter electron scattering is more sensitive to the high velocity tail which can be significantly different depending on the dark matter halo model. This work quantifies the effects of different dark matter halo models and parameter choices on these rates, finding an $\mathcal{O}(0.01\%)$ to $\mathcal{O}(100\%)$ change in the rate predictions in silicon targets. Secondly, we use a different lepton, the muon, to search for dark matter at colliders. In particular, we simulate a particular class of dark matter model, known as flavored dark matter, at a theoretical future muon collider to predict the capability of such a machine to detect or place bounds on this model, if it were to be built. We focus on the less-explored regime of feeble dark matter interactions, which suppresses the dangerous lepton-flavor violating processes, gives rise to dark matter freeze-in production, and leads to long-lived particle signatures at colliders. We find that the interplay of dark matter freeze-in and its mediator freeze-out gives rise to an upper bound of around TeV scales on the dark matter mass. The signatures of this model depend on the lifetime of the mediator, and can range from generic prompt decays to more exotic long-lived particle signals. In the prompt region, we calculate the signal yield, study useful kinematics cuts, and report tolerable systematics that would allow for a $5\sigma$ discovery. In the long-lived region, we calculate the number of charged tracks and displaced lepton signals of our model in different parts of the detector, and uncover kinematic features that can be used for background rejection. We show that, unlike in hadron colliders, multiple production channels contribute significantly which leads to sharply distinct kinematics for electroweakly-charged long-lived particle signals. This dissertation includes previously published co-authored material.
Open Access
HOW A COMMUNITY CLINIC HAS RESPONDED TO THE WAR ON DRUGS: AN ETHNOGRAPHIC STUDY
(University of Oregon, 2024-12-19) Arredondo Sanchez Lira, Carolina; Yarris, Kristin
This thesis explores the profound social impacts that the War on Drugs in Mexico has had on women who use drugs and reside in the border town of Tijuana, Baja California. The War on Drugs was a failed policy initiated by Felipe Calderon, Mexican president from 2006 to 2012, which has led to an increase in violence, corruption, human rights violations, and marginalization of vulnerable communities. Nonetheless, Mexican president Andres Manuel Lopez Obrador (AMLO), who promised to dismantle the War on Drugs, has instead strengthened it. From the beginning of his presidency in 2018 until 2024, AMLO deployed the National Guard to combat the insecurity in Mexico. Also, AMLO decided not only to cut all funding to organizations but also not to support harm reduction measures. The lack of resources and funding has made it challenging for people who use drugs, especially women, to receive the needed support. Through the lens of the Social Ecological Model (SEM), this research aims to investigate the multifaceted effects of the War on Drugs on women who use drugs, emphasizing gender and drug use. The project focuses on PrevenCasa, a non-profit community clinic in Tijuana. As well the study further examines the social and health outcomes of the harm reduction services provided by the clinic to women who use drugs. The research employs an ethnographic method, including observations and semi-structured interviews with focus group participants and staff members in the clinic. As well the thesis aims to understand what are the socio-effects of the services that PrevenCasa, a community health organization in the Zona Norte, has to offer to women who use drugs. Findings from this study will contribute to a better understanding of the negative impact of harmful policies on marginalized communities, such as women who use drugs. As well the project will contribute to understanding the critical role that harm reduction can have in improving the health and well-being of women who use drugs.
Open Access
Who’s Behind the Lens? An Exploration of Access, Relationships, and Storytelling in the Production of Photographs of U.S. Presidents
(University of Oregon, 2024-12-19) Jackson, Emilee; Newton, Julianne
This dissertation investigates the lived experiences and perspectives of 14 U.S. presidential photographers – both those granted access within the "velvet rope" at the White House and those who remain outside it. The study illuminates the roles of Official White House photographers and still news photographers in the press corps, their perceptions of their role, and the potential impact of their work on the American public. Based on a multifaceted qualitative approach incorporating historical context, theoretical perspectives, interviews with renowned photographers, exploratory focus groups, and a close reading of selected photographs, analysis uncovered core themes of access, relationships, and storytelling as critical factors in presidential photography. By using elements of grounded theory, this research integrates framing and visual rhetoric theories through the lens of symbolic interactionism theory. Findings reveal how access to the inner circle of the presidency provides photographers with unique perspectives, enabling them to create compelling narratives that can impact public perceptions. Through both journalistic and documentary photography, these photographers function as storytellers and documenters of history. Furthermore, collaborative relationships between photographers and presidents emphasize the intricate interplay of trust, authenticity, and representation. Focus group findings suggest that the viewing public is likely unaware of the differences between the roles of news photographers and Official White House photographers and why the roles matter and that viewers/readers rely on their own interpretations of visual indicators in photographs to determine the role of the photographer. Participants interpreted behind-the-scenes moments to have different tones than photographers believed they were conveying. They also expected to see the president in professional moments rather than in relaxed moments. A close reading of selected photographs confirmed that, although similarities and differences in photos taken by White House and news photographers are difficult to interpret in small sets, differences in their framing and the visual narratives presented are evident. This dissertation addresses a gap in research by exploring the connections among photojournalism ethics, the history of presidential photography, and the creation of political imagery of U.S. presidents.
Open Access
Remote Delivery of Culturally Adapted Prevent-Teach-Reinforce for Families (PRT-F) Program with Chinese American Families of Young Children with Intellectual and Developmental Disability
(University of Oregon, 2024-12-19) Zhu, Jinlan; Machalicek, Wendy
The prevalence of challenging behavior, such as aggression, self-injurious behavior, tantrums, and noncompliance with everyday expectations among young children with intellectual and developmental disability (IDD), is higher than the prevalence of challenging behavior for children without disabilities. Without appropriate intervention, challenging behavior tends to persist in individuals with IDD, contributing to subsequent problems in school, home, and community life, as well as negatively impacting future independence. Parent education and training programs focused on supporting parents of children with IDD to learn and use evidence-based behavioral interventions with their child contribute to improved parent strategy use and increased confidence in supporting their child’s behavior and ultimately support decreased child challenging behavior and increased appropriate adaptive behavior. Prevent, Teach, and Reinforce for Families (PTR-F) is a manualized and evidence-based positive behavior support program, including parent education and training to assist families in resolving their children’s mild to moderate severity challenging behavior in home and community settings. Few studies have empirically examined the effectiveness of PTR-F or other positive behavior support parenting programs for culturally diverse families of children with disabilities. The current study examined the efficacy and social validity of a culturally adapted and telepractice version of the PTR-F for Chinese American families of young children with IDD in the United States. The PTR-F intervention program was culturally adapted for enhanced cultural responsivity to Chinese American families using Bernal’s Ecological Validity Model as a guiding framework and delivered remotely for improved feasibility in recruitment for the planned single-case research design study and enhanced scalability in future research. Six mothers and their children with autism spectrum disorder (ASD) participated. Two independent randomized concurrent multiple baseline designs across six parent-child dyads were used to examine the effects of the culturally adapted PTR-F intervention program when delivered by mothers on the decreased rate of target child challenging behavior. Two randomization strategies, case randomization and intervention start-point randomization, were used in this study. Each dyad was randomly to different baseline lengths ,and range-bound start point randomization was used to a priori determine the length of the baseline phase for each participant while retaining the logic of the staggered introduction of the intervention over time across parent-child dyads. Visual analysis combined with the non-parametric Tau-U and parametric magnitude of treatment effect size standardized mean difference analysis, revealed mixed results with a medium effect found for child challenging behavior in the first concurrent multiple baseline design group and small effects found in the second group. Parent perceptions of the acceptability, feasibility and effectiveness of the culturally adapted PTR-F intervention program’s goals, procedures, and outcomes were collected using standardized social validity questionnaires with the addition of open-ended responses and reported using descriptive statistics and parent responses to open-ended questions. Chinese American families of children with developmental disabilities including ASD are absent in the intervention literature. This novel examination of the effects of a culturally adapted family centered intervention on child challenging behavior suggests the promise of a culturally adapted PTR-F for Chinese American families to address their child’s challenging behavior. Implications for future research and practice are discussed.
Open Access
The Drama of the Dialectic: Hegel, Marx, and the Theory of Appropriation
(University of Oregon, 2024-12-19) Knowlton Jr, Kenneth; Muraca, Barbara
This dissertation develops a theory of appropriation through an account of dialectical materialism as a relational ontology. Appropriation is argued as creative-aesthetic activity definitive of the human species-essence through which sociality metabolically transforms. In turn, the universality of appropriation becomes an analytic for designating historical change through the mode of appropriation, where the transhistorical and ontological dimension of appropriation take on a historically specific character. I begin with a critical reconstruction of German Idealism through an account of FWJ Schelling’s critique of GWF Hegel’s Science of Logic. Schelling’s criticism initiates a tendency to misrepresent Hegel’s dialectical logic that extends into 20th century philosophy, a misrepresentation which also transposed itself onto the works of Karl Marx and Frederick Engels. I trace this lineage in Part I, critically responding to it. Part II provides a materialist interpretation of Hegel’s Science of Logic, focusing on essence, necessity, universality, telos, and reason. I demonstrate the relational and anti-representational character of Hegelian dialectics through a systematic account of these categories. Consequently, I draw on Hegel to provide the logico-theoretical structure of the concept of appropriation as constitutive of a dialectical relational ontology. Part III develops appropriation and the mode of appropriation through an engagement with the works of Marx and Engels. I argue that their work is predicated on a dialectical relational ontology fundamental to their political, economic, and historical analysis. I show that the mode of appropriation is constituted by a triadic structure of changing labor-forms, property-forms, and belonging-forms that together elucidate socio-historical transformation.
Open Access
Novel entangling gates and scalable trap designs for trapped-ion quantum computing
(University of Oregon, 2024-12-19) Quinn, Alexander; Wang, Hailin
Trapped ions have received much attention as a platform for quantum computing, a purpose they may be well-suited for on account of their natural features: Ions of the same species are inherently identical; they can be manipulated using electric and magnetic fields via both their net charge, which allows external fields to couple to ions’ center-of-mass motion, and via internal electronic transitions; and when they are isolated from the environment, their states can remain coherent for long time spans, at least by the standards of quantum information experiments. Despite these features, the ability to carry out useful quantum computing in trapped ions is limited, with two major practical constraints being 1) the difficulty of coherently controlling ions’ states and 2) the limited physical scale of existing trapped-ion quantum computers, which typically hold no more than tens of ions. This document present a set of projects meant to help address these limitations through different tracks, including the development and testing of control techniques for trapped ions and the design of new types of traps. Firstly, we present an entangling gate carried out on quantum bits (qubits) encoded in a set of electronic energy levels that have been relatively unexplored until recently and whose viability for quantum information processing may enable more efficient architectures for trapped ion quantum computing. Specifically, we entangled a pair of qubits encoded in two Zeeman sublevels of the D5/2 metastable excited state of a pair of trapped 40Ca+ ions using Raman laser beams 10s of THz detuned from resonance to limit scattering rates (a fundamental error source in Raman gates). We demonstrate that high-fidelity gates (98.6(1)% subtracting state preparation and measurement error, and 99.1(1)% subtracting both SPAM and erasure) can be performed with this encoding scheme, show that the main source of error is technical noise, and employ a leakage detection scheme that allows decay or deshelving from the metastable level to be heralded, potentially making correcting this class of errors easier. After this, we shift focus from control techniques and discuss scalable trap design, focusing on a project to fabricate ion traps using 3D printing, a technique that could potentially enable microfabricated traps with high harmonicity, power efficiency, and depth of confinement relative to the 2D (planar) microfabricated traps widely used in efforts to scale up trapped-ion quantum computing. We design, simulate, fabricate, and carry out preliminary electrical testing on metallized trap prints, demonstrating some minimum viability of the technique, and show computationally that traps produced this way could have trapping characteristics similar to those of other 3D microfabricated designs. Finally, we consider scalable trap design for continuousvariable quantum computing (CVQC), a quantum computing scheme where, in trapped ions, information is encoded in the states of the vibrational modes of an ion crystal. A key requirement for universal CVQC is the ability to perform non-Gaussian operations, which can be difficult to carry out electronically. In this work, we present a 2D ion trap design that can perform non-Gaussian motional operations in an all-electronic way, with the design process accounting for the geometric limitations imposed by 2D traps. We consider some of the motional operations possible with this trap and estimate their associated coupling rates, finding that under a reasonable set of assumptions about operating parameters, coupling rates for non-Gaussian operations could be achieved that are comparable to those previously achieved with all-electronic Gaussian operations could likely be achieved with this trap design. This dissertation includes co-authored, published material.
Open Access
Examining Mechanisms of Altered Skeletal Muscle Cellular Passive Mechanics in the Context of Acute Fatigue and Age
(University of Oregon, 2024-12-19) Privett, Grace; Callahan, Damien
Skeletal muscle stiffness influences locomotor function and may predict soft-tissue injury risk. Recent literature suggests fatiguing exercise transiently reduces whole skeletal muscle stiffness, yet the underlying mechanisms remain unclear. Therefore, the purpose of this dissertation was to i) determine whether fatiguing exercise reduces cellular passive stress and Young’s Modulus in conjunction with altered phosphorylation of the sarcomere protein titin, ii) extend these measures to samples of composite tissue, and iii) assess whether aging mediates the effect of fatigue on skeletal muscle passive mechanics. Methods: 9 young and 8 older males and females completed unilateral fatiguing exercise followed by biopsy of the fatigued and non-fatigued Vastus Lateralis. In younger adults, passive stress and strain were compared in fatigued versus non-fatigued single fibers and titin phosphorylation was quantified via liquid chromatography mass spectrometry (LC-MS, Aim 1). Cellular measures were then translated to bundles of 12-14 fibers with intact extracellular matrix (ECM, Aim 2). Finally, cellular and tissue-level mechanical measures were compared in young versus older adults (Aim 3). Results: We observed that fatiguing exercise reduced passive stress and Young’s Modulus in myosin heavy chain (MHC) IIA and IIA/X fibers from young and older males, but not females. Titin phosphorylation was altered by fatiguing exercise, with no apparent sex-based differences. In-vitro treatments to phosphorylate or dephosphorylate titin did not support a direct link between titin phosphorylation and altered cellular passive mechanics. In bundles, fatiguing exercise only affected passive modulus in young females, and this fatigue-induced difference was at least partially due to titin. Aging did not affect cellular or bundle passive measures, nor did aging mediate the response to fatigue. Discussion: These data suggest that fatiguing exercise reduces cellular passive stress and modulus in muscle from older and younger males, in conjunction with altered titin phosphorylation. Furthermore, intracellular proteins appear to contribute to tissue mechanics, though their relative influence is unclear. Ultimately this study contributes to efforts aimed at understanding the chronic and acute mediators of skeletal muscle mechanics.
Open Access
Investigating Early Childhood Trajectories of Parenting Feelings and Behavior on Outcomes for Children with Developmental Delays and Disabilities
(University of Oregon, 2024-12-19) Pompan, Emily; McIntyre, Laura Lee
Social-emotional development is foundational to learning and has been linked to long-term academic, behavioral and mental health outcomes for children (i.e., Jones et al., 2015). In early childhood, social-emotional development is encouraged primarily through familial relationships. Children with developmental delays and disabilities (DD) are more likely to experience social-emotional delays which can impact participation in these everyday interactions and opportunities for learning. Families with children with DD may face additional stressors which compete with resources and opportunities for relationship-enhancing interactions, further impacting child social-emotional development (Chan & Neece, 2018). Parent-mediated interventions have been linked to gains in child social-communication and behavior (Stahmer & Pellecchia, 2015; Webster-Stratton & Reid, 2010; Wetherby et al., 2014), which may facilitate positive parent-child interactions. Such interventions may also support parent and family well-being. Less is known about the mechanism through which parent-mediated interventions impact child social-emotional outcomes for children with DD. The present study of 180 caregivers enrolled in a primary prevention RCT examined (1) how positive feelings and attitudes (PFA) about their parenting role relate to parenting behaviors during parent-child play, (2) change in the context of parent-mediated early intervention, and (3) predict social-emotional outcomes at school-age for toddlers with DD. Analyses included confirmatory factor analyses and latent growth models within a structural equation modeling framework. Results identified parent-mediated intervention as a mechanism for change in parenting play behavior and showed positive PFA as a predictor for school-age social interaction outcome. The significance of findings, study limitations, and suggestions for future research are discussed.
Open Access
Perceiving Different Types of Bad People: How Moral Person Prototypes Influence Moral Impressions
(University of Oregon, 2024-12-19) Dimakis, Sarah; Mauro, Robert
In response to a complex and information dense world, we organize related information into categories (e.g., furniture, animals) to make it easier to apply existing knowledge to newly encountered objects and situations (Rosch, 1978). Categories are represented in the mind as cognitive prototypes: examples that possess common features of category members (Posner & Keele, 1968; Reed, 1972; Rosch & Mervis, 1975). A key feature of prototype-based categories is that unobserved characteristics are inferred to category members once the prototype is activated (Cantor & Mischel, 1977; Osherson et al., 1990). I propose in this dissertation that we use moral person categories to make inferences about the unobserved or unobservable immoral characteristics of others, which influences our decisions about with whom to interact and how to interact with them. In a series of studies, I demonstrated that people perceive multiple bad person categories, examined their properties, and tested a prototype model of moral character evaluation against dimensional models. This dissertation is the first rigorous investigation of the structure and properties of perceived bad person categories. In Study 1, fifty prototypical characteristics of a bad person (e.g., lacking empathy, selfishness, racism) were gleaned from previous literature and augmented with additional characteristics generated by participants in a free-listing task. In Study 2, participant sorting data of characteristics from Study 1 revealed that respondents distinguished between multiple types of bad people (e.g., psychopath, abuser, narcissist, bigot). Additionally, categorical and dimensional models of bad person characteristics were generated from the responses in Study 2 and tested with new data in Study 3. Consistent with prototype-based categories, unobserved immoral characteristics that were prototypical of a category were more likely to be attributed to exemplars of that category compared to exemplars of competing bad person categories. Further, prototype models outperformed dimensional or multidimensional models, but prototype-unidimensional dual models performed the best. Thus, people infer prototype-consistent immoral characteristics to exemplars of a category, and additionally infer prototype-inconsistent immoral characteristics that are similar in morality to the exemplar (but not similar on other social dimensions such as intelligence or sociability). Additionally, further providing support for multiple bad person prototype-based categories, large differences were observed in the perception of four bad person prototypes regarding their morality, competence, sociability, gender, race, age, physical appearance, the innateness and permanence of their immoral characteristics, and the ways respondents prefer to interact with them. Overall, this dissertation provides strong evidence against the unidimensional model of morality commonly used in the moral character evaluation literature and in support of a model of moral character evaluation that includes cognitive prototypes. This research may have significant implications for why we make errors that others are bad based on harmless or morally irrelevant characteristics (e.g., physical appearance, harmless behaviors), including in criminal justice contexts. In the future, the methods presented in this paper should be replicated with diverse samples to assess commonalities and differences in the cognitive prototypes of bad people across relevant subgroups (e.g., liberals versus conservatives, experts versus novices).
Open Access
Risking Race: Risk Assessment and the Policing of Blackness in the United States
(University of Oregon, 2024-12-19) Scott, Brett; Lowndes, Joseph
This dissertation explores how risk governance has produced racial inequality in the United States. It is particularly interested in understanding how race informs the ways that risk is defined, assessed, experienced and policed. My primary argument is that risk is a condition of Blackness in the United States because Black people are necessarily and always connected to risk. Anti-Black racism is often mediated through the distinct relationship that Black populations have with risk, risk assessment and risk governance. Black Americans are subjected to structural violences that are often justified because under the guise of risk prevention. Black folk have been socially constructed as risky and therefore in need of control and domination. However, it isn’t simply that Black people are viewed as risks to others, but that there is a feedback loop to designation which puts Blacks at risk for harm because of their status as risky people. The dual position that Black people hold as both the bearers and bringers of risk remains an under-theorized form of racial inequality because society tends to view risk from a lens of colorblind objectivity. Nevertheless, inequalities in how risk is defined, assessed, and police continue to widen the gap between Black and white Americans and, as this study show, these inequalities exist in a multitude of institutions including the insurance market, housing industry and the criminal justice system. This dissertation takes seriously the problem of risk inequality as it plays out along racial lines in the United States. This work is a welcome addition to political science because critically engaging with the racial inequalities of risk governance allows for an analysis of racial inequality that is often overlooked by policy makers and academics alike. I hope is that this study is a springboard for future research that seeks to understand the complexities of racial inequalities in a modern world that is increasingly focused on risk prevention and mitigation.
Open Access
Gas Mobility Patterns in Crystal Mush Analog Experiments
(University of Oregon, 2024-12-19) Etheredge, MaKayla; Dufek, Josef
Volatile movement through crystal mush, which controls the efficiency of gas escape, is poorly understood. Previous studies using 2-D (Hele-Shaw) analog experiments show that the geometry (finger, fracture) and efficiency of gas escape is controlled by particle concentration. I extend this approach by adding photoelastic particles to track formation and destruction of force chains. 2-D analog (Hele-Shaw) experiments using solid particles (photoelastic disks), fluid (corn syrup), and gas (nitrogen) are used to quantify the role of varying injected gas flux (1000 cm3/s to 10000 cm3/s) on crystal and melt migration patterns. Experiments can be classified by gas geometry into fingering, transition and fracture regime; recorded pressure and light intensity provide a proxy for particle stresses caused by the gas flux rate.