Search results

Title: Online innovization : towards knowledge discovery and achieving faster convergence in multi-objective optimization
Creator: Gaur, Abhinav
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Ì0300nnovization'' is a task of learning common principles thatexist among some or all of the Pareto-optimal solutions in amulti-objective optimization problem. Except a few earlierstudies, most innovization related studies were performed onthe final non-dominated solutions found by an evolutionary multi-objective algorithm eithermanually or by using a machine learning method.Recent studies have shown that these principles can be learnedduring intermediate iterations of an optimization run...
Show moreÌ0300nnovization'' is a task of learning common principles thatexist among some or all of the Pareto-optimal solutions in amulti-objective optimization problem. Except a few earlierstudies, most innovization related studies were performed onthe final non-dominated solutions found by an evolutionary multi-objective algorithm eithermanually or by using a machine learning method.Recent studies have shown that these principles can be learnedduring intermediate iterations of an optimization run and simultaneously utilized in thesame optimization run to repair variables to achieve a fasterconvergence to the Pareto-optimal set. This is what we are calling as ò0300nline innovization'' as it is performed online during the run of an evolutionary multi-objective optimization algorithm. Special attention is paid to learning rules that are easier to interpret, such as short algebraic expressions, instead of complex decision trees or kernel based black box rules.We begin by showing how to learn fixed form rules that are encountered frequently in multi-objective optimization problems. We also show how can we learn free form rules, that are linear combination of non-linear terms, using a custom genetic programming algorithm. We show how can we use the concept of k0300nee' in PO set of solutions along with a custom dimensional penalty calculator to discard rules that may be overly complex, or inaccurate or just dimensionally incorrect. The results of rules learned using this custom genetic programming algorithm show that it is beneficial to let evolution learn the structure of rules while the constituent weights should be learned using some classical learning algorithm such as linear regression or linear support vector machines. When the rules are implicit functions of the problem variables, we use a computationally inexpensive way of repairing the variables by turning the problem of repairing the variable into a single variable golden section search.We show the proof of concept on test problems by learning fixed form rules among variables of the problem, which we then use during the same optimization run to repair variables. Different principleslearned during an optimization run can involve differentnumber of variables and/or variables that arecommon among a number of principles. Moreover, a preferenceorder for repairing variables may play an important role forproper convergence. Thus, when multiple principles exist, itis important to use a strategy that is most beneficial forrepairing evolving population of solutions.The above methods are applied to a mix of test problems and engineering design problems. The results are encouraging and strongly supportsthe use of innovization task in enhancing the convergence of an evolutionary multi-objective optimization algorithms. Moreover, the custom genetic program developed in this work can be a useful machine learning tool for practitioners to learn human interpretable rules in the form of algebraic expressions.
Show less

Title: "My life is changed but the trust ain't there to trust somebody else" : experiences of recovery from intimate partner abuse of women of Mexican heritage in a mid-size city in Michigan
Creator: Palma-Ramirez, Evangelina
Date: 2020
Collection: Electronic Theses & Dissertations
Description: This exploratory qualitative study aimed to gain an understanding of the experiences of recovery from intimate partner abuse (IPA) of 17 women of Mexican heritage in a mid-size urban city in Michigan. IPA was defined as any type of physical, sexual, stalking, psychological harm or coercive control by a former intimate partner or spouse. Two aspects were explored: experiences of abuse and experiences of recovery from abuse. The study used a feminist theory and intersectionality perspective as...
Show moreThis exploratory qualitative study aimed to gain an understanding of the experiences of recovery from intimate partner abuse (IPA) of 17 women of Mexican heritage in a mid-size urban city in Michigan. IPA was defined as any type of physical, sexual, stalking, psychological harm or coercive control by a former intimate partner or spouse. Two aspects were explored: experiences of abuse and experiences of recovery from abuse. The study used a feminist theory and intersectionality perspective as a guiding framework to understand the experiences of women considering their contextual situation. Data were collected using a semi-structured questionnaire and analyzed using a constructivist grounded theory by Charmaz. The findings revealed that women understand their experiences of abuse as being connected to their early socialization about gender roles, history of child abuse, lack of sexual education, and the influence of the environment. Also, the participants revealed they experienced overlapping types of abuse: psychological, coercion, economic, physical, sexual, and stalking. Despite the negative impact of the abuse on participants' physical and mental health, findings showed that women were able to recover from the abuse and to move on with their lives. Data suggested that the recovery was a gradual ongoing process of physical and psychological healing. Participants identified empowering experiences that helped them in their recovery from IPA. Such empowering experiences included life-changing religious realizations, receiving services in Spanish, acquiring more education, receiving counseling services, and getting a job. Receiving social support from family and friends and having access to resources were identified as factors that aided in the recovery from IPA. However, some participants experienced limited access to such resources due to economic constraints, cultural beliefs about gender roles, and the impact of immigration policies.Lastly, findings revealed that experiences of recovery from IPA vary based on whether women decided to leave their partners or to remain with them. Implications for culturally sensitive interventions for Latinas of Mexican heritage are discussed as well as implications for future research on issues of recovery for this specific Latino subgroup.
Show less

Title: Use of administative claims data to design and emulate a clinical trial in acute stroke patients comparing rehabilitation at inpatient rehabilitation facilities to skilled nursing facilities
Creator: Simmonds, Kent P.
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Stroke affects nearly 800,000 people every year in the United States and is a leading cause of adult disability. After hospitalization half of stroke patients continue to require medical and rehabilitation services provided at inpatient rehabilitation facilities (IRFs) or skilled nursing facilities (SNFs). In general, IRFs provide time-intensive therapy for two to three weeks, while SNFs provide moderately intensive therapy for four- to five-weeks. There is substantial variation in the...
Show moreStroke affects nearly 800,000 people every year in the United States and is a leading cause of adult disability. After hospitalization half of stroke patients continue to require medical and rehabilitation services provided at inpatient rehabilitation facilities (IRFs) or skilled nursing facilities (SNFs). In general, IRFs provide time-intensive therapy for two to three weeks, while SNFs provide moderately intensive therapy for four- to five-weeks. There is substantial variation in the utilization of these alternative rehabilitation settings, but their relative comparative effectiveness remains uncertain. A randomized controlled trial (RCT) would provide an unbiased comparative effectiveness estimate, but the design of such a trial is complicated by several practical and ethical issues. The overarching purpose of this dissertation was to use Medicare claims data to inform the design and to emulate such a trial. In the first aim, we sought to identify patient and hospital level factors that were associated with IRF or SNF discharge and characterize the heterogeneity of hospital effects that influenced discharge to an IRF (vs. SNF). From a retrospective cohort of 145,894 stroke patients, we used multi-level multivariable models to identify several patient- and hospital- level factors that were independently associated with discharge setting. We also showed that hospitals contributed around a third of the variation in IRF (vs. SNF) discharge, but there was substantial variation in the effect that specific hospitals had on influencing IRF discharge. The second aim, was to identify a target trial population that optimized the explanatory-pragmatic balance of a subsequent RCT. To identify this population, we profiled hospitals based on their propensity to discharge stroke patients to IRFs (vs. SNFs) and inferred IRF and SNF referral networks for each hospital. The final target trial population included 44,950 patients (30.8% of the starting sample) who were treated at 441 hospitals (14.5%) and subsequently discharged to 745 IRFs (64.8%) and 5,974 SNFs (48.2%).The third aim was to emulate three alternate RCTs that compared patient outcomes at IRFs vs. SNFs. Trial #1 used the target trial population identified in Aim 2, while trials #2 and 3 excluded increasingly infrequently used IRFs and SNFs. Comparative effectiveness was estimated using a matched propensity score analysis. Overall, on a relative basis, patients treated at IRFs were between 18-35% more likely to be successfully discharged home (i.e., alive and at home for >30 days) and were between 11-15% less likely to die within one year of acute care discharge. The variation in the effect size estimates across the trials was driven by poorer outcomes among patients treated at infrequently used SNFs. Finally, we identified that a moderate sized unmeasured confounder would nullify the observed differences.In conclusion, we identified that referring hospitals are a major driver of IRF or SNF use, and that patients treated at IRFs had better outcomes (relative to SNF patients). However, our results were limited by the inability to adjust for potentially important unmeasured confounders. A pragmatic RCT would eliminate such biases and provide a more valid comparative effectiveness estimate of these two alternative rehabilitation settings.
Show less

Title: ER stress sensor IRE1-alpha and its implications in progression of hepatocellular carcinoma
Creator: Oak, Amrita
Date: 2019
Collection: Electronic Theses & Dissertations
Description: "The endoplasmic reticulum (ER) is the site for protein folding and maturation. ER stressors, both physiological and pharmacological, can result in activation of the unfolded protein response (UPR). Palmitate, a saturated fatty acid, is one such ER stressor and leads to induction of the UPR. This is primarily through the activation of Inositol Requiring Enzyme-1 (IRE1) leading to splicing of XBP1 mRNA. However, the mechanism of this activation is unclear. With the aid of a bimolecular...
Show more"The endoplasmic reticulum (ER) is the site for protein folding and maturation. ER stressors, both physiological and pharmacological, can result in activation of the unfolded protein response (UPR). Palmitate, a saturated fatty acid, is one such ER stressor and leads to induction of the UPR. This is primarily through the activation of Inositol Requiring Enzyme-1 (IRE1) leading to splicing of XBP1 mRNA. However, the mechanism of this activation is unclear. With the aid of a bimolecular fluorescence complementation (BiFC) assay, we identified two crucial residues on the transmembrane domain (TM) of IRE1, S450 and W457, that are drivers of palmitate mediated activation. Previous research from our group suggested that IRE1 also has binding sites for palmitate on its cytosolic domain (CD). However, IRE1-CD protein expressed in E. coli was over-phosphorylated which possibly affected its binding to PA. To investigate this, we developed a protocol for expression and purification of wild type and mutant IRE1-CD protein in insect Sf21 cells. A fluorescence polarization based binding assay was performed to determine whether palmitate binds to residues on the IRE1-CD protein. Previously our laboratory demonstrated that palmitate induced the migration of cancer cells as well as transcription factors (TF) involved in epithelial-to-mesenchymal transition (EMT). Here, we investigated the role of IRE1 activation on these processes. Using CRISPR gene editing to generate IRE1 knockouts in liver and breast cancer cell lines, we observed that IRE1 mediates the upregulation in EMT-TFs, a decrease in the expression of the desmoplakin (DSP) protein, and an increase in the migration of liver and breast cancer cells. DSP is a critical component of desmosomes, which function to maintain the structural integrity at adjacent cell-cell contacts.In addition to migration, the effect of XBP1 splicing on metabolism has not been studied. We found the activation of IRE1-XBP1 is accompanied by changes in the metabolic genes involved in glycolysis, fatty acid oxidation, gluconeogenesis, and ceramide metabolism, suggesting that some of the metabolic effects of palmitate are mediated through IRE1. These results could have implications on the development of chemotherapeutic strategies. This study paves the way for further investigations into the far-reaching effects of activation of the UPR on cell survival, metabolism, and chemo-tolerance."--Pages ii-iii.
Show less

Title: Analysis of the petrology and geochemistry of the magmas of the Galema range in the Somalian Plateau, Ethiopia : a probe of lithospheric processes of the northern east African rift system
Creator: Chiasera, Brandon
Date: 2020
Collection: Electronic Theses & Dissertations
Description: As a continental rift evolves towards a mid ocean ridge, the continental lithosphere must rupture and extension must become accommodated exclusively by seafloor spreading. During this process, extensional strain is initially accommodated along the nascent rift margins, subsequently localizing to zones of focused magmatic intrusion. Asthenospheric conditions such as increased mantle potential temperature or presence of an upwelling, deep seated mantle anomaly may influence, or be responsible...
Show moreAs a continental rift evolves towards a mid ocean ridge, the continental lithosphere must rupture and extension must become accommodated exclusively by seafloor spreading. During this process, extensional strain is initially accommodated along the nascent rift margins, subsequently localizing to zones of focused magmatic intrusion. Asthenospheric conditions such as increased mantle potential temperature or presence of an upwelling, deep seated mantle anomaly may influence, or be responsible for, these extensional processes. While these processes are integral in the process of continental rifting, how they relate and influence each other remains an area of active scientific inquiry and debate. The Main Ethiopian Rift (MER) in East Africa is the ideal location to study extensional processes. We examine the Galema range, an area of focused magmatic activity along the eastern margin of the Central Main Ethiopian Rift, which is morphologically similar to areas of focused magmatism within the rift. To better understand the complex processes involved in continental rifting and how they are related, we present whole-rock, major and trace element data on 77 samples of the Galema range magmas, including isotopic geochemistry on 22 of these samples. We find that whole rock thermodynamic modeling and thermobarometric calculations on mineral-liquid pairs suggest that fractionation (and hence magma stalling depths) within the Galema range is polybaric (70303 and 30303 kbar). These results, when compared to zones of focused intrusion within the rift, indicate an incipient magmatic plumbing system. Trace element models of melt generation reveal melting conditions of 1418-1450°C at 2.9-3.2 GPa. These conditions reveal that Ethiopian mantle TP is elevated by 603038-100°C over ambient. In contrast, Si/Mg activity thermobarometry, which probes the point at which these magmas last re-equilibrated with the mantle, yielded broadly similar temperatures (1435-1474°C) but at lower pressures (2.1-2.6 ± 0.2 GPa). We interpret these results as evidence for magma stalling at a thermo-mechanical boundary to ascent, which we contend is the lithosphere-asthenosphere boundary (LAB). Isotopic analyses of the magmas of the Galema range indicate the presence of signatures of the Afar plume, Pan-African lithosphere, and depleted mantle. A subset of these isotopic analyses indicates the presence of a previously unknown, 4th mantle end member, which we attribute to be a contribution from a recently created, and destroyed, sub-continental lithosphere beneath the eastern Ethiopian plateau. We contend that diking associated with the Galema range, which pre-dates magmatic belts within the rift; thermomechanically modified the lithosphere along this margin. The thermomechanical modification of the lithosphere mantle along this margin facilitated the subsequent development of within-rift magmatic chains. The implications of this are that off-rift magmatic activity may play an integral role in facilitating the development of rift architecture. We interpret contrasting results between two trace element modeling approaches as evidence for magma ponding subsequent to melt generation. While the continental lithosphere has thinned during extension, the lithosphere remains relatively thick late into the rifting process, despite the development of magmatic extension at crustal depths. The presence of an isotopic signature of a sub-continental lithospheric mantle indicates rapid creation and destruction of lithospheric material in processes attributed to the upwelling Afar plume. This process may be one way in which the lithosphere is thinned in the EARS, along with foundering and assimilation of material into the depleted asthenosphere.
Show less

Title: Fluid reasoning as a predictor of deviant workplace behaviors
Creator: Matusik, James Garrett
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Relative to the sizable body of work investigating the relationship between intelligence and task performance, one facet of overall job performance, very little research has been conducted on the relationship between intelligence and counterproductive work behavior, a different but equally important facet of job performance. Furthermore, the little research that has been conducted on the intelligence-counterproductive work behavior relationship has yielded entirely inconsistent results -...
Show moreRelative to the sizable body of work investigating the relationship between intelligence and task performance, one facet of overall job performance, very little research has been conducted on the relationship between intelligence and counterproductive work behavior, a different but equally important facet of job performance. Furthermore, the little research that has been conducted on the intelligence-counterproductive work behavior relationship has yielded entirely inconsistent results - while some researchers have found a negative relationship between intelligence and counterproductive work behavior, others have found null or positive relationships. This, coupled with the reality that none of these studies have explicitly tested causal mechanisms, provides us with an entirely unclear understanding of this relationship. Thus, the goal of this dissertation is to more carefully examine the potential relationship(s) between intelligence and counterproductive work behavior by (a) capturing both overt and covert counterproductive work behaviors, (b) testing a previously identified, but thus far untested, mediating mechanism, and (c) incorporating moderators, selected based upon criminology research that has leveraged a psychological approach in the explanation of individual deviance.
Show less

Title: From sitting to living : examining the role of meditation in understanding the emotion regulatory mechanisms of mindfulness
Creator: Lin, Yanli
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Mindfulness has received widespread interest for its purported benefits to emotional well-being. Despite a rapidly growing literature base supporting the salutary relationship between mindfulness and emotion regulation, little is known about how mindfulness confers its emotion regulatory benefits. A pertinent, yet underexplored, approach to addressing this question is to examine neural mechanisms involved in the effects of mindfulness training via meditative practice to "off-the-cushion"...
Show moreMindfulness has received widespread interest for its purported benefits to emotional well-being. Despite a rapidly growing literature base supporting the salutary relationship between mindfulness and emotion regulation, little is known about how mindfulness confers its emotion regulatory benefits. A pertinent, yet underexplored, approach to addressing this question is to examine neural mechanisms involved in the effects of mindfulness training via meditative practice to "off-the-cushion" changes in emotion regulation. The primary aim of the present study was therefore to determine the extent to which change in neural oscillatory activity (i.e., alpha and theta power) during mindfulness meditation related to subjective (i.e., self-reported negative affect) and neural (i.e., late positive potential [LPP]) measures of emotional reactivity elicited during a subsequent affective picture viewing task. Toward this end, a multimodal experimental paradigm was employed to test three predictions: 1) participants randomized to engage in brief guided mindfulness meditation, relative to those randomized to a control condition, would exhibit increased alpha and theta power during meditation relative to rest; 2) participants in the meditation group, but not those in the control group, would exhibit attenuated LPP responses and report lower negative affect during the picture viewing task; 3) the predicted increases in alpha and theta power during meditation would correlate with the predicted reductions in the LPP and self-reported negative affect during picture viewing. Contrary to expectations, the guided meditation did not produce demonstrable effects on alpha and theta power, the LPP, or self-reported negative affect relative to the control condition. Change in theta, but not alpha, power during meditation was, however, positively correlated with the early time window of the LPP, suggesting that change in neural activity during meditation may relate to subsequent emotion processing. Overall, the study demonstrated the utility of investigating the relationship between what occurs during mindfulness meditation and its purported effects on emotion regulation. Moreover, reflections on the unexpected nature of the null findings dovetail with the prevailing consensus that theoretical and methodological factors unique to the construct of mindfulness are integral in shaping the direction, design, and interpretability of mindfulness research.
Show less

Title: Systematic analysis of the signal responsive gene regulatory network governing Myxococcus xanthus development
Creator: Saha, Shreya
Date: 2020
Collection: Electronic Theses & Dissertations
Description: Studies of signal-induced gene expression in bacteria have contributed to understanding of how bacteria cope with environmental stress. As an extensively studied model, Myxococcus xanthus provides fascinating insights into how changes at the level of gene expression enable which bacteria to survive environmental insults such as nutrient limitation. Upon starvation M. xanthus cells glide into aggregates and form mounds that mature into fruiting bodies as some cells form spores. Previously, our...
Show moreStudies of signal-induced gene expression in bacteria have contributed to understanding of how bacteria cope with environmental stress. As an extensively studied model, Myxococcus xanthus provides fascinating insights into how changes at the level of gene expression enable which bacteria to survive environmental insults such as nutrient limitation. Upon starvation M. xanthus cells glide into aggregates and form mounds that mature into fruiting bodies as some cells form spores. Previously, our group defined 24-30 h poststarvation as the critical period for commitment to spore formation, when cells commit to form spores despite perturbation of the starvation signal by nutrient addition. The process of multicellular development that culminates in sporulation is governed by a network of signal-responsive transcription factors that integrate signals for starvation and cellular alignment. In this dissertation I present the first systematic approach to elucidate the network dynamics during the commitment period.In the network, MrpC is a starvation-responsive transcription factor, whereas FruA is a transcription factor that responds to cellular alignment conveyed by C-signaling. Transcription of fruA is dependent on MrpC binding, and FruA activity is proposed to be posttranslationally regulated by C-signaling, although the mechanism is unknown. FruA and MrpC cooperatively regulate transcription of the dev operon. My systematic analysis of the network dynamics supported a model in which posttranslational activation of FruA by C-signaling is critical for dev transcription and for commitment to spore formation. Similar to dev, MrpC and C-signal-activated FruA combinatorially controlled transcription of the late-acting fadIJ operon involved in spore metabolism. Regulation of late-acting operons implicated in spore coat biogenesis (exoA-I, nfsA-H, MXAN_3259-MXAN_3263) was discovered to be under complex control by MrpC and FruA. My evidence suggests that transcription of these operons depends at least in part on a C-signal-dependent switch from negative regulation by unactivated FruA to positive regulation by activated FruA during the period leading up to and including commitment to sporulation. MrpC negatively regulated exo and MXAN_3259 during mound formation, but positively regulated nfs. During commitment to sporulation, MrpC continued to positively regulate nfs, switched to positive regulation of MXAN_3259, and continued to negatively regulate exo. A third transcription factor, Nla6, appeared to be a positive regulator of all the late genes. We propose that in combination with regulation by Nla6, differential regulation by FruA in response to C-signaling and by MrpC controls late gene expression to ensure that spore resistance and surface characteristics meet environmental demands.
Show less

Title: Turkish teachers and imams and the making of Turkish German difference
Creator: Van Wyck, Brian
Date: 2019
Collection: Electronic Theses & Dissertations
Description: This dissertation investigates the intersections of education, Islam, and knowledge production in the history of postwar migration to West Germany. It focuses on how Germans and Turks grappled with the permanent presence of Turkish guest workers, refugees, and their families in the Federal Republic of Germany (FRG) from the 1960s onward. To understand how ideas about this population of Turkish Germans shaped notions of race, culture, and belonging in both countries, two surprisingly under...
Show moreThis dissertation investigates the intersections of education, Islam, and knowledge production in the history of postwar migration to West Germany. It focuses on how Germans and Turks grappled with the permanent presence of Turkish guest workers, refugees, and their families in the Federal Republic of Germany (FRG) from the 1960s onward. To understand how ideas about this population of Turkish Germans shaped notions of race, culture, and belonging in both countries, two surprisingly under-researched groups are used as a lens: Turkish teachers and imams. Both were charged with seeing to the educational and spiritual needs of what was West Germany's largest immigrant population by 1973. As such, policies, practices, and debates surrounding the hiring, supervision, and activities of relatively small numbers of teachers and imams offer insight into what a broad spectrum of state and civil society stakeholders in both countries believed they knew about Turkish Germans, what differentiated them from the German majority or Turks in Turkey proper, and what interventions were made necessary by that difference. Teachers and imams were simultaneously actors producing knowledge about Turks in the FRG for audiences in both countries, agents tasked with carrying out interventions at the behest of various stakeholders on the basis of this knowledge, and, as Turkish Germans, were themselves subjects of this knowledge regime. As such, they reveal the complicated dynamics underlying why and how what was known about Turkish German difference changed over time. This in turn identifies shifts in ideas about the nation, race, and Islam in Turkey and Germany.Comparing teachers and imams and using sources in Turkish and German as diverse as theater, poetry, oral history, diplomatic correspondence, and the academic and popular press, this dissertation breaks with several common scholarly and popular assumptions. First, it demonstrates the contingency of the emergence in the 1980s of Islam as the most salient aspect of Turkish difference and an essential element of Turkish national identity, rather than a marker of membership in the broader, international "Muslim world." The project identifies the centrality of Islam to the racialization of Turkish difference and the role of Turkish expertise in this process of essentialization. Second, the comparison between teachers and imams highlights the contextual nature of the construction of this essential difference. Even as imams were positioned as experts with proprietary knowledge of Turkish Islam, Turkish teachers lost their privileged status and their cultural and linguistic knowledge was increasingly understood as backwards and irrelevant in the context of the universalistic German school. Thus, Turkish difference in German schools was perceived differently than when it was imagined in a mosque or Koran course. The dissertation offers an account of the development and implications of this interplay between belonging and exclusion, and knowledge and ignorance. This allows it to complicate previous literature which has located German policies and attitudes toward foreigners in the legacies of the Third Reich or in an unchanging and particularly German ethnoracial conception of the nation.
Show less

Title: Examining dynamic interpersonal processes associated with alliance rupture in psychotherapy
Creator: Luo, Xiaochen
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Alliance ruptures refer to tensions and negative processes between therapist and patient. Identifying ruptures is important because research shows that ruptures play an important role in establishing therapeutic alliance and in promoting therapeutic changes. However, previous studies have not used within-person methodology to explore the dynamic and dyadic processes of interpersonal behaviors in ruptures and thus there is little evidence to guide clinicians in the identification of ruptures....
Show moreAlliance ruptures refer to tensions and negative processes between therapist and patient. Identifying ruptures is important because research shows that ruptures play an important role in establishing therapeutic alliance and in promoting therapeutic changes. However, previous studies have not used within-person methodology to explore the dynamic and dyadic processes of interpersonal behaviors in ruptures and thus there is little evidence to guide clinicians in the identification of ruptures. The current study utilizes an intensive single-case analytic approach to examine how patients' and therapists' dominance, warmth, and interpersonal complementarity are associated with in-session confrontation ruptures and withdrawal ruptures in sixteen adult psychotherapy sessions from eight independent therapeutic dyads. Interpersonal behaviors and ruptures were coded and processed at a half-minute interval. Dynamic factor analysis models were fit to examine the relationships between interpersonal variables and ruptures for each single session. Generalizability was examined by comparing results within dyads and across dyads. Patient's increased cold or dominant behaviors, as well as the dyad's increased dominance complementarity, were related with confrontation ruptures in more than one third of the sessions. Therapist's decreased dominant behaviors and patient's increased dominant behaviors were related with withdrawal ruptures in more than one third of the sessions. The results also identified dyad- and session-specific patterns that did not generalize across cases but may be of clinical interest. These findings highlight the important roles of both therapists' and patients' behaviors as well as their synchronization on dominance in the development of alliance ruptures, extended our knowledge on within-person interpersonal dynamics associated with ruptures, and emphasized the need to examine both idiographic and nomothetic processes of alliance ruptures.
Show less

Title: A container-attachable inertial sensor for real-time hydration tracking
Creator: Griffith, Henry
Date: 2019
Collection: Electronic Theses & Dissertations
Description: The underconsumption of fluid is associated with multiple adverse health outcomes, including reduced cognitive function, obesity, and cancer. To aid individuals in maintaining adequate hydration, numerous sensing architectures for tracking fluid intake have been proposed. Amongst the various approaches considered, container-attachable inertial sensors offer a non-wearable solution capable of estimating aggregate consumption across multiple drinking containers. The research described herein...
Show moreThe underconsumption of fluid is associated with multiple adverse health outcomes, including reduced cognitive function, obesity, and cancer. To aid individuals in maintaining adequate hydration, numerous sensing architectures for tracking fluid intake have been proposed. Amongst the various approaches considered, container-attachable inertial sensors offer a non-wearable solution capable of estimating aggregate consumption across multiple drinking containers. The research described herein demonstrates techniques for improving the performance of these devices.A novel sip detection algorithm designed to accommodate the variable duration and sparse occurrence of drinking events is presented at the beginning of this dissertation. The proposed technique identifies drinks using a two-stage segmentation and classification framework. Segmentation is performed using a dynamic partitioning algorithm which spots the characteristic inclination pattern of the container during drinking. Candidate drinks are then distinguished from handling activities with similar motion patterns using a support vector machine classifier. The algorithm is demonstrated to improve true positive detection rate from 75.1% to 98.8% versus a benchmark approach employing static segmentation. Multiple strategies for improving drink volume estimation performance are demonstrated in the latter portion of this dissertation. Proposed techniques are verified through a large-scale data collection consisting of 1,908 drinks consumed by 84 individuals over 159 trials. Support vector machine regression models are shown to improve per-drink estimation accuracy versus the prior state-of-the-art for a single inertial sensor, with mean absolute percentage error reduced by 11.1%. Aggregate consumption accuracy is also improved versus previously reported results for a container-attachable device.An approach for computing aggregate consumption using fill level estimates is also demonstrated. Fill level estimates are shown to exhibit superior accuracy with reduced inter-subject variance versus volume models. A heuristic fusion technique for further improving these estimates is also introduced herein. Heuristic fusion is shown to reduce root mean square error versus direct estimates by over 30%. The dissertation concludes by demonstrating the ability of the sensor to operate across multiple containers.
Show less

Title: Determinants of eating behaviors of us army ROTC cadets in Midwestern universities
Creator: George, Beatriz G.
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Young adults 18-25 years of age, the largest demographic of the military, experience a high burden of obesity and eating disorders (ED) despite an emphasis on physical fitness, body composition, and operational readiness. Etiologic models for obesity and ED suggest body dissatisfaction (BD), dieting, negative affect (NA), and affect regulation represent potentially shared pathways. However, no studies have examined these factors and their shared pathways in military personnel, including ROTC...
Show moreYoung adults 18-25 years of age, the largest demographic of the military, experience a high burden of obesity and eating disorders (ED) despite an emphasis on physical fitness, body composition, and operational readiness. Etiologic models for obesity and ED suggest body dissatisfaction (BD), dieting, negative affect (NA), and affect regulation represent potentially shared pathways. However, no studies have examined these factors and their shared pathways in military personnel, including ROTC cadets. The overarching aim of this dissertation research was to investigate if ED symptoms were associated with body mass index (BMI), an indicator of obesity, and to describe potential correlates of their development. Three specific aims of this research focus on: 1) the prevalence and correlates of ED risk classification and symptoms in ROTC cadets, 2) the association between ED symptoms and BMI, and their potentially shared mechanisms, psychological inflexibility related to BD and dieting, and 3) the gaps in knowledge about eating behaviors and mediators of eating behaviors within the ROTC context and from perspective of ROTC cadets.In 2018, US Army ROTC cadets (n = 205) were recruited from two Midwestern universities and completed questionnaires about demographics, military-specific eating behaviors and mediators of eating behaviors, ED symptoms, and anthropometric measures. Chi-square, multivariable logistic regression, and multiple linear regression were performed in determining the rate of ED risk classification and correlates of ED risk classification and symptoms (Aim 1). Two measures of psychological inflexibility related to BD and dieting, in addition to the data for Aim 1, were used in mediation path analysis to examine the association of ED symptoms to BMI, and the indirect effects as mediated by psychological inflexibility related to BD and dieting (Aim 2). A purposively selected sample of eighteen cadets participated in one-on-one, semi-structured telephone interviews on eating behaviors and their mediators in the context of ROTC (Aim 3). Interviews were analyzed using thematic analysis to identify the most important themes and determinants related to eating behaviors in ROTC cadets.We found that ED symptoms and ED risk classification are prevalent in a sample of US Army ROTC cadets (10.1% of sample). Correlates associated with greater likelihood of ED risk classification and elevated ED symptoms were: sex, dieting, and military contextual factors such as attempting dieting and weight loss to meet body composition standards, and peers' comments on weight. Total ED symptoms scores were positively associated with BMI and partially mediated by psychological inflexibility related to BD and dieting. Cadets discussed perceived determinants of eating behaviors which included traditional determinants (e.g. time, money, nutrition knowledge) and ROTC-context specific determinants (e.g. preparation for body composition assessments and body image perceptions), which contributed to unhealthy weight control behaviors (dieting) and negative body image perceptions (BD) for some cadets. In conclusion, the prevalent correlates for eating disorder symptoms and risk in the sample of US Army ROTC cadets in this study were factors related to the enforcement of body composition standards and body image perceptions in the military context which may contribute to the development of dieting, BD, and NA. Longitudinal and/or intervention studies on this important topic may benefit our understanding of how ED symptoms and obesity develop over time and how targeting dieting, BD, NA, and affect regulation may be leveraged to mitigate ED and obesity to promote physical fitness, operational readiness and health in military personnel.
Show less

Title: Measuring the half-life of O-26
Creator: Redpath, Thomas
Date: 2019
Collection: Electronic Theses & Dissertations
Description: An interesting property of some neutron-unbound systems is true two-neutron emission where the neutrons are emitted simultaneously as opposed to a sequential decay through an intermediate state. Since neutrons are only affected by the angular momentum barrier, the timescale for this process is much shorter than for two proton emission which is dominated by the Coulomb barrier. One such case is ²2076O where a very low decay energy was measured and the two valence neutrons are expected to...
Show moreAn interesting property of some neutron-unbound systems is true two-neutron emission where the neutrons are emitted simultaneously as opposed to a sequential decay through an intermediate state. Since neutrons are only affected by the angular momentum barrier, the timescale for this process is much shorter than for two proton emission which is dominated by the Coulomb barrier. One such case is ²2076O where a very low decay energy was measured and the two valence neutrons are expected to occupy d-wave orbitals. Also, the ground state of ²2075O is located 700 keV higher. Using the data from a previous measurement of the decay energy, the MoNA collaboration extracted a lifetime of 4:5+1:1-1:5(stat) ± 3(syst) ps with a confidence level of 82% (1). Results from a recent measurement give T1/2 = 5:0+2:0-1:6 (stat) ±1:7 (syst) ps and support the previous finding.Measurements of neutron-unbound systems using invariant mass spectroscopy are often performed using low-intensity radioactive ion beams. Low reaction yields can be countered by using a thicker target but at the expense of larger uncertainties in the reconstructed invariant mass. A new segmented target was designed to address this trade-off, and it was first used in this experiment to re-measure the ground state half-life of ²2076O.
Show less

Title: Quantifying impacts of anthropogenic disturbances on wildlife
Creator: Mudumba, Tutilo
Date: 2019
Collection: Electronic Theses & Dissertations
Description: In this dissertation, I examined the interconnectedness of human population growth, energy development, human-wildlife coexistence, and wildlife population ecology. In Chapter One, I reviewed the literature and categorized the effects of oil extraction on wildlife. Broadly, the effects included: i) increased poaching, ii) curtailed space-use, iii) increased harassment, iv) risk of introduction of invasive species, v) contamination, and vi) heightened the severity of impacts due to synergistic...
Show moreIn this dissertation, I examined the interconnectedness of human population growth, energy development, human-wildlife coexistence, and wildlife population ecology. In Chapter One, I reviewed the literature and categorized the effects of oil extraction on wildlife. Broadly, the effects included: i) increased poaching, ii) curtailed space-use, iii) increased harassment, iv) risk of introduction of invasive species, v) contamination, and vi) heightened the severity of impacts due to synergistic effects. Overall, I found that efforts to evaluate the consequences of oil extraction, particularly in peer-reviewed form, were limited. Research should be conducted pre-, during, and post-oil extraction to increase knowledge of the effects of oil extraction on wildlife to enable more effective policy decisions.In Chapter Two, I studied human-wildlife co-existence and found that conflict was the most important factor determining local people's attitude towards poaching. Less than 20% of the local people had ever visited the park and there was limited flow of benefits for local communities from protected areas. My findings highlight the importance of providing remedies compatible with local livelihoods and could be used to improve wildlife management to address poaching.In Chapter Three, I predicted the African lion (Panthera leo) carrying capacity in Murchison Falls National Park (MFNP) from existing primary prey biomass. I found that the extant African lion density was four times less than what the prey biomass inside the park could support. I compared the African lion density estimated from prey biomass to that estimated from direct counts and found that estimating lion density from indirect methods such as prey biomass can result in the overestimation of existent populations.In Chapter Four, I described an approach for estimating the density, configuration, and lethality of poacher-set snares and discussed their effects on wildlife inside MFNP. Murchison Falls National Park had the highest known density of wire snares in the world. I provide a litany of anthropogenic and environmental configurations that made snares more likely to catch an animal. The ability of snares to trap an animal were significantly predicted by snare thickness, noose width, vertical drop, wire circumference, grass height, and anchor tree diameter at breast height. Regulating the disposal of dis-used vehicle tires which provided the material for the wire snares was likely to reduce snare poaching inside the park. Additionally, providing alternative livelihoods to people involved in snare poaching would discourage the recruitment of locals in snare poaching. My method of surveying snares provides the opportunity to standardize temporal and spatial measurements of snare density and configuration as a first step to refine mitigation techniques.I conclude my dissertation with a summary of my key findings and recommendations for future research. The results of my research are applicable to biodiverse-rich portions of the world that are at risk of human development. My methods could also be used to quantify the severity of subsistence poaching. This is relevant because subsistence poaching remains a significant conservation challenge in the 21st century.
Show less

Title: Advances in oscillometric blood pressure measurement
Creator: Chandrasekhar, Anand
Date: 2019
Collection: Electronic Theses & Dissertations
Description: High blood pressure (BP) is a major cardiovascular risk factor that is treatable, yet hypertensionawareness and control rates are low. Ubiquitous BP monitoring technology could improve hypertensionmanagement, but existing devices require an inflatable cuff and are not compatible withsuch anytime, anywhere measurement of BP. Oscillometry is the blood pressure (BP) measurementprinciple of most automatic cuff devices. We extended the oscillometric principle, which is usedby most automatic cuff...
Show moreHigh blood pressure (BP) is a major cardiovascular risk factor that is treatable, yet hypertensionawareness and control rates are low. Ubiquitous BP monitoring technology could improve hypertensionmanagement, but existing devices require an inflatable cuff and are not compatible withsuch anytime, anywhere measurement of BP. Oscillometry is the blood pressure (BP) measurementprinciple of most automatic cuff devices. We extended the oscillometric principle, which is usedby most automatic cuff devices, to develop a couple of instruments to measure cuff-less BP usinga smartphone-based device and standalone iPhone application. As the user presses her/his fingeragainst the smartphone, the external pressure of the underlying artery is steadily increased while thephone measures the applied pressure and resulting variable amplitude blood volume oscillations.A smartphone application provides visual feedback to guide the amount of pressure applied overtime via the finger pressing and computes systolic and diastolic BP from the measurements.We prospectively tested the smartphone-based device for real-time BP monitoring in humansubjects to evaluate usability (n = 30) and accuracy against a standard automatic cuff-based device(n = 32). We likewise tested a finger cuff device, which uses the volume-clamp method of BPdetection. About 90% of the users learned the finger actuation required by the smartphone-baseddevice after one or two practice trials. The device yielded bias and precision errors of 3.3 and 8.8mmHg for systolic BP and [Special character(s) omitted]5:6 and 7:7 mmHg for diastolic BP over a 40 to 50 mmHg range of BP.These errors were comparable to the finger cuff device. Cuff-less and calibration-free monitoringof systolic and diastolic BP may be feasible via a smartphone. In addition, we tested the iPhoneapplication. The application yielded bias and precision errors of -4.0 and 11.4 mmHg for systolicBP and -9.4 and 9.7 mmHg for diastolic BP (n = 18). These errors were near the finger cuff deviceerrors. This proof-of-concept study surprisingly indicates that cuff-less and calibration-free BPmonitoring may be feasible with many existing and forthcoming smartphones.These devices use empirical algorithms, already descried in the literature, to estimate bloodpressure. Hence, the next objective was to establish formulas to explain three popular empiricalalgorithms- the maximum amplitude, derivative, and fixed ratio algorithms. A mathematicalmodel of the oscillogram was developed and analyzed to derive parametric formulas for explainingeach algorithm. Exemplary parameter values were obtained by fitting the model to measuredoscillograms. The model and formulas were validated by showing that their predictions correspondto measurements. The formula for the maximum amplitude algorithm indicates that it yields aweighted average of systolic and diastolic BP (0.45 and 0.55 weighting) instead of commonlyassumed mean BP. The formulas for the derivative algorithm indicate that it can accurately estimatesystolic and diastolic BP (<1.5 mmHg error), if oscillogram measurement noise can be obviated.The formulas for the fixed ratio algorithm indicate that it can yield inaccurate BP estimates, becausethe ratios change substantially (over a 0.5-0.6 range) with arterial compliance and pulse pressureand error in the assumed ratio translates to BP error via large amplification (>40). The establishedformulas allow for easy and complete interpretation of perhaps the three most popular oscillometricBP estimation algorithms in the literature while providing new insights. The model and formulasmay also be of some value towards improving the accuracy of automatic cuff BP measurementdevices.
Show less

Title: Analysis of drinking water quality and sanitation in a peri-urban area of Dar es Salaam, Tanzania
Creator: Ngasala, Tulakemelwa Mhamilawa
Date: 2019
Collection: Electronic Theses & Dissertations
Description: "While the Sustainable Development Goal 6 called for universal access to water and sanitation by 2030, the challenge of achieving this goal seems daunting in the context of the bourgeoning peri- urban communities of the developing world. These areas are often in a regulatory grey area, receiving municipal water on an irregular basis and lacking sanitation and other basic services. And yet, SDG 6 recognizes that improving global health and wellbeing is critically linked to addressing this...
Show more"While the Sustainable Development Goal 6 called for universal access to water and sanitation by 2030, the challenge of achieving this goal seems daunting in the context of the bourgeoning peri- urban communities of the developing world. These areas are often in a regulatory grey area, receiving municipal water on an irregular basis and lacking sanitation and other basic services. And yet, SDG 6 recognizes that improving global health and wellbeing is critically linked to addressing this problem. A multi-method study of the peri-urban area of Dar es Salaam was conducted to determine the extent of the problem and to make recommendations for system-wide approaches to alleviate the risk of waterborne disease. Existing water sources in the area were identified. Water collection and storage practices were assessed at the household level to determine how water from relatively clean sources becomes contaminated. Escherichia coli (E. coli), nitrate, and total dissolved solid (TDS) were analyzed as indicators for the sewage contamination. Bivariate correlation and univariate regression analyses were used to identify the sources of contamination. The assessment focused on the relationship and association of water contamination with site-specific variables. The variable that had the highest negative impact to the water source was analyzed by using a groundwater flow and contaminant transport model as a tool to make recommendations for proper site-specific sanitation practices. Of the three water sources identified (city water, vendors, and domestic wells), water quality analysis showed that city water at the point of collection (POC) was deemed excellent, whereas it diminished at the point of use (POU) for all three water sources. Reasons for change in water quality at POU and POC were due to mixing of water from different water sources at homes during storage. Using a multinomial regression model, the main reason for mixing water was determined to be the dilution of the salty taste of well water (p < 0.05) and insufficient storage containers (p < 0.05). Of the three water sources identified, domestic wells were found to be the most contaminated. Further analysis on the domestic wells showed a significant contamination, where 80% of wells tested contained E. coli. Also, 58% and 81% of wells tested had concentrations of nitrate and TDS, respectively, that exceeded the WHO guidelines. Univariate regression analysis confirmed the association of contaminants with distance of a well from a sanitation system and well depth (p < 0.05). Groundwater transport modeling showed a strong correlation between the tracer and contaminants and the tracer and distance and helped identify the safe well setback distance that is specific to site conditions, soil type, and aquifer properties. Groundwater modeling was shown to be a good assessment tool for contamination within an aquifer system in urban overpopulated areas of developing countries. Our findings also indicate that the risk of exposure to waterborne disease comes from a combination of factors that involve multiple actors, from improved awareness and sanitation practices to improved regulatory oversight, supply practices, and sanitation technologies."--Pages ii-iii.
Show less

Title: "Exile is hell" : Black internationalism and Robert F. Williams's activist network in the Cold War, 1950-1969
Creator: Mares, Richard M.
Date: 2019
Collection: Electronic Theses & Dissertations
Description: The precarious positions of African American political exiles provide an instructive window into the fluctuations of international support for the black freedom struggle. Exile Is Hell examines the strategies used by Robert F. Williams's activist network to survive and maintain their involvement in the Civil Rights-Black Power Movement from outside the United States. Expatriates such as Williams, Richard Gibson, Julian Mayfield, and others most plainly bore the vicissitudes of political...
Show moreThe precarious positions of African American political exiles provide an instructive window into the fluctuations of international support for the black freedom struggle. Exile Is Hell examines the strategies used by Robert F. Williams's activist network to survive and maintain their involvement in the Civil Rights-Black Power Movement from outside the United States. Expatriates such as Williams, Richard Gibson, Julian Mayfield, and others most plainly bore the vicissitudes of political shifts occurring in the 1960s against the backdrop of the Cold War. Exile Is Hell tracks this ebb and flow by foregrounding the day-to-day experiences of Williams, Gibson, Mayfield, and others to reveal their methods of navigating an erratic political climate and capricious activist community. International rhetoric formed an integral component of the Black Power era, yet many activists struggled to forge lasting, transnational coalitions due to the variable politics of the Cold War. Using Williams as the central hub of this activist network, this project contributes a detailed narrative of exile through a collective biography that explores the daily work of expanding the Civil Rights-Black Power Movement to incorporate global ambitions. This research further establishes the impact of changes in international support upon an activist network in order to extrapolate the effects on the African American freedom struggle.
Show less

Title: Repatriation tax costs and foreign investment decisions of U.S. multinationals : evidence from the anticipation of the 2017 U.S. tax reform
Creator: Vuong, Anh Nguyet
Date: 2019
Collection: Electronic Theses & Dissertations
Description: "In this study, I investigate whether the expectation of a future reduction in repatriation tax costs affects the foreign investment decisions of U.S. multinational corporations (U.S. MNCs). I find that, during the period in which members of Congress proposed legislation for a switch to a territorial tax system, foreign subsidiaries of U.S. MNCs significantly increased capital investment activities, compared to the subsidiaries of non-U.S. MNCs in the same country. The increase in capital...
Show more"In this study, I investigate whether the expectation of a future reduction in repatriation tax costs affects the foreign investment decisions of U.S. multinational corporations (U.S. MNCs). I find that, during the period in which members of Congress proposed legislation for a switch to a territorial tax system, foreign subsidiaries of U.S. MNCs significantly increased capital investment activities, compared to the subsidiaries of non-U.S. MNCs in the same country. The increase in capital investment is concentrated among subsidiaries of U.S. MNCs that are subject to higher potential repatriation tax costs, and hence would benefit more from a potential reform. Furthermore, I do not find any evidence consistent with the alternative explanation that agency costs of excess cash holdings drive the increases in investment during this period. On the contrary, the increases in foreign investment activities are marginally greater among subsidiaries that are subject to lower agency costs. Together, these results suggest that the expectation of lower future repatriation tax costs has inadvertently incentivized U.S. MNCs to invest more abroad. My study contributes to the literature that examines firms' real investment responses to anticipated tax incentives and our understanding of the consequences of the recent U.S. tax reform."--Page ii.
Show less

Title: Quantitative investigation of the membrane protein degradation mechanism by membrane-integrated AAA protease FtsH under native environments
Creator: Yang, Yiqing (Graduate of Michigan State University)
Date: 2019
Collection: Electronic Theses & Dissertations
Description: "Controlled degradation of misassembled and dispensable proteins is a crucial cellular process for maintaining the quality control of proteomes. In cells, one of the important carriers of this process is AAA+ (ATPases Associated with diverse cellular Activities) proteases, which mediate ATP-dependent proteolysis. The FtsH family proteins are the only membrane integrated AAA+ proteases, which critically contribute to membrane protein degradation. To investigate the mechanisms of membrane...
Show more"Controlled degradation of misassembled and dispensable proteins is a crucial cellular process for maintaining the quality control of proteomes. In cells, one of the important carriers of this process is AAA+ (ATPases Associated with diverse cellular Activities) proteases, which mediate ATP-dependent proteolysis. The FtsH family proteins are the only membrane integrated AAA+ proteases, which critically contribute to membrane protein degradation. To investigate the mechanisms of membrane protein degradation mediated by FtsH, I successfully reconstituted the degradation process using FtsH of E. coli in a lipid bilayer environment (Chapter 2). I also developed a six-helical bundle intramembrane protease GlpG of E. coli into a model membrane substrate to study the quantitative relationship between folding and degradation (Chapter 2). I found that FtsH has a substantial ability to accelerate unfolding of membrane substrates up to 800 fold using ATP hydrolysis, and the intrinsic folding properties of the substrates such as local stability, spontaneous unfolding rates, and hydrophobicity also impact degradation rates. Finally, I quantified the total ATP cost that FtsH consumes to degrade membrane proteins (Chapters 3 and 4). To degrade membrane proteins, FtsH needs to overcome large energetic costs for unfolding substrates in the membranes and extracting them towards its protease domain located outside the membrane. I found that FtsH utilizes ATP hydrolysis in degrading membrane proteins with similar efficiency to other AAA+ proteases in degrading water-soluble substrates. This efficiency is achieved by coupling multiple ATP hydrolysis events to degradation in a highly cooperative manner. These findings provide new insights into the physical principles of ATP-dependent degradation of membrane proteins, and the in vitro system developed will serve as a model for further refining the mechanisms of membrane protein degradation."--Pages ii-iii.
Show less

Title: Testing phonological representations through behavioral and electrophysiological methods
Creator: Trotter, Andrew (Graduate of Michigan State University)
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Languages differ in the sounds that make up their phonemic inventories. These sounds, or phonemes, are represented abstractly in the mind of a speaker, making up the underlying representations of lexical items. Additional sounds may exist in a given language, surfacing via a derivative process of phonological rule application, where they are called allophones. There are also many speech sounds that are unrepresented entirely, as separate categories, within a particular language. In either...
Show moreLanguages differ in the sounds that make up their phonemic inventories. These sounds, or phonemes, are represented abstractly in the mind of a speaker, making up the underlying representations of lexical items. Additional sounds may exist in a given language, surfacing via a derivative process of phonological rule application, where they are called allophones. There are also many speech sounds that are unrepresented entirely, as separate categories, within a particular language. In either case, learners of a second language have difficulty perceiving and producing the sounds that do not exist or have differing phonological status in their native language. English and Spanish present us with an ideal case study of these differences. Both languages contain the [d], [ð], and [027E] sounds, but they differ in how they organize them. While /d/ is a phoneme in both languages, in Spanish [ð] is an allophone of /d/, while /027E/ is a separate phoneme. Conversely, [027E] is an allophone of /d/ in English while /ð/ is a separate phoneme. There is a large amount of literature showing that sounds that contrast in one's language are more perceptible than those that do not. Boomershine et al., (2008) showed this to be true of the [d], [ð], and [027E] sounds in native Spanish and English speakers, where Spanish speakers more easily perceived the differences between [d]/[027E] than [d]/[ð]. English speakers, on the other hand, had difficulty distinguishing [d] from [027E], but no issue with [d] and [ð]. The studies in this dissertation extend this work by first replicating the results of Boomershine et al., (2008) with a group of monolingual English speakers as well as a group of native Spanish speakers on a forced choice perception task. Additionally, I add a group of native English-speaking advanced learners of Spanish and show that their perception of the relevant sounds is more like that of the native Spanish speakers on a number of behavioral metrics. In a second study, I test the same three speaker groups in an Electroencephalography study (EEG) using the mismatch negativity protocol (MMN) which has been previously shown to probe auditory categorical perception (Naatanen et al., 1978). If the MMN is sensitive to phonemic contrasts, as has been claimed, the expectation is that, similarly to the behavioral perception results, speakers should show larger mismatch responses to phonemic contrasts than to allophonic contrasts. I also explore the possibility of using the MMN to probe category formation in the learner group. However, while there are subtle differences in the EEG data for each speaker group, the results are contra predictions. Instead, all three language groups pattern similarly on each sound in the EEG study, with larger MMNs being elicited by the [027E]/[d] comparison than the [ð]/[d] comparison. This mismatch response suggests that the MMN is not probing phonological status but is sensitive to phonetic category. A discussion of methodology and the validity of using the MMN in phonology research is included.
Show less

MSU Libraries

Digital Repository

Enabled Filters

Pages

Pages

MSU Libraries

Digital Repository

You are here

Search results

Pages

Pages