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Acquired Dysarthria and Dysphagia in Pediatric Acquired Brain Injury
Full text linkThis research investigates the correlation between motor speech disorders (MSDs) and dysphagia resulting from acquired brain injuries (ABI) in the pediatric population. Dysarthria, a motor speech disorder affecting the motor execution of speech, can be either congenital or acquired. Dysphagia, a swallowing disorder, may arise from various factors following neurological impairment, including muscle weakness, muscular incoordination, timing errors, and reduced range of motion (Jones et al., 2016; Perry et al., 2021; Roden & Altman, 2013; Yagi et al., 2017). Although substantial research exists on dysarthria and dysphagia in adults, their correlation in children, particularly with acquired motor speech disorders, remains underexplored (Morgan & Lie geois, 2010; Knuijt et al., 2014). This study addresses if dysarthria predicts dysphagia and how the severity of both conditions, along with age and sex, affects this relationship.
The study involves 16 children, aged 5-17 years, assessed at Children’s Hospital Colorado during in-patient rehabilitation admissions. Each participant underwent neuroimaging and swallow evaluations. Assessments included the Colorado Motor Speech Framework (CMSF) (Duane et al., 2024) and the Test of Children’s Speech + (TOCS +) (Hodge et al., 2007). Speech samples were recorded, transcribed using ELAN, and evaluated by a panel of Speech-Language Pathologists and graduate clinicians for intelligibility and ii severity. The correlation between dysarthria and dysphagia was analyzed using neuroimaging, severity ratings, and swallow studies.
The goal of this study is to highlight the correlation between dysphagia and dysarthria in acquired neurological conditions, aiming to enhance diagnostic and therapy services for the pediatric population following neurological injury.
This study aimed to investigate the relationship between pediatric acquired brain injury, dysarthria, and dysphagia. While statistical significance was not achieved, descriptive analyses revealed patterns that suggest important clinical insights. All three children diagnosed with mixed dysarthria also presented with dysphagia. Additionally, three out of four children with flaccid dysarthria exhibited dysphagia, as did all three children with single-subject motor speech diagnoses (spastic, UUMN, and hypokinetic dysarthria). A higher incidence of both dysarthria and dysphagia was observed in children with Guillain-Barre syndrome and traumatic brain injury (TBI). In contrast, no cases of dysphagia were found in children with ataxic dysarthria or apraxia of speech at the time of evaluation.
The findings highlight the importance of conducting thorough motor speech and swallow evaluations for children following ABIs. These evaluations are critical, particularly since none of the participants had a motor speech differential diagnosis prior to the study, and clear patterns regarding the presence of dysphagia were not readily apparent. The results underscore the need for clinicians to consider the potential overlap of motor speech and swallow disorders in this population.</p
Astrocytic Responses to Nicotine
Full text linkAn improved understanding of nicotine neurobiology is needed to reduce or prevent chronic addiction, ameliorate the detrimental effects of nicotine withdrawal, and increase successful cessation of use. Nicotine use genome-wide association studies (GWAS) suggest an astrocytic role for nicotine responses. Previously, we found that AKT2 expression is restricted to astrocytes in mice and humans and may play a role in the nicotinic responses of astrocytes. Astrocyte activation was characterized in LPS and nicotine exposure paradigms using Sholl analysis. These studies revealed LPS and nicotine differences in astrocyte activation. We used primary mouse cortical astrocytes for our in vitro studies. We found that live imaging as a basis for astrocyte models is useful for studying the dynamic nature of astrocytic activation. We used an Adeno-Associated Virus (AAV) to transfect astrocytes with mCherry for visualization. To identify astrocyte-expressed genes that may be relevant to nicotine use in humans, we used transcriptome-wide association study (TWAS) results from the GWAS & Sequencing Consortium of Alcohol and Nicotine use (GSCAN) along with astrocyte expression data to identify genes of interest (GOI) to assess potential astrocyte involvement in nicotine responses. Using a CRISPR approach to knock down GOI expression, we are screening 25-50 GSCAN-identified genes that show expression in human and mouse astrocytes. We assess GOI's role in astrocyte size and morphology in primary mouse astrocytes following nicotine treatment using area analysis. We have found Clusterin to be a promising target and have generated a colony of Clusterin KO mice. We found that CLUSTERIN partially reduces acute nicotinic astrocyte activation in vivo. In vivo, chronic and behavioral studies are planned to confirm Clusterin KO affects astrocytic response. Behavioral assessments of astrocyte-specific Akt2 deficient mice were conducted, revealing the impacts of AKT2 loss on behaviors relevant to nicotine use and proving principle results for our ongoing GOI studies. These results will allow for the identification of potential novel drug targets and will improve the current understanding of the astrocytic response to nicotine.</p
Beams from the Lotus Moon: Ōtagaki Rengetsu and Her Cultural Networks
Full text linkThroughout her career in Kyoto during the late Tokugawa (1603-1868) and early Meiji (1868-1912) periods, the Japanese Buddhist nun Ōtagaki Rengetsu 太田垣蓮月 (1791-1875) created unique combinations of ceramics, waka poetry, calligraphy, and painting which attracted many disciples and imitators. Her whimsical and unpretentious style in each of these media earned her an esteemed artistic profile. She was also well-established as a creative mentor and attracted a diverse circle of followers.
This thesis examines the artistic communities that shaped Rengetsu’s creative practice, highlighting her participation in a variety of circles through a range of artistic modes. It argues that her relationships with the other artists in her orbit were inseparable from how her style and influence developed. Through focused examinations of her poetry and calligraphy, tea ceramics, and collaborative paintings, it demonstrates the ways that Rengetsu and her artwork functioned as a nexus for myriad cultural networks.</p
Colonial Hybridity of Eurasian Borderlands in Banine’s Memoir "Days in the Caucasus"
Full text linkThis thesis explores colonial hybridity of Eurasian borderlands in Banine’s memoir Days in the Caucasus through the lenses of postcolonial and decolonial studies. By employing discourse and textual analysis, it examines how Banine’s narrative mimics, resists, and rewrites dominant cultural discourses. Banine’s memoir offers a complex portrait of colonial hybridized identity formation at the intersection of gender, empire, and class. This study reads her narrative as both a confirmation and a critique of imperial discourse, revealing Baku as a space of contradictory pressures faced by colonial subjects, especially women, and a three-tier cultural hierarchy, wherein the local culture is perceived as the least valuable, Russian – more advanced, and Western – the most advanced. Banine’s memoir speaks to the intricacies of female subjectivity, national identity, and cultural hybridity in a liminal historical moment. By refusing to perform palatable identity or offer easy cultural reconciliation, it remains strikingly relevant in its insistence on the complexities and tensions of hybrid subjectivity. The memoir thus serves as a powerful illustration of how colonial histories and cultural encounters shape personal subjectivity. Ultimately, this project positions Banine’s memoir as an understudied but vital text in the study of postcolonial literature from Eurasian borderlands.</p
Decentr(a)l(i)zed: A Computational Text Analysis of the Evolving AI Regulatory Landscape in the United States
Full text linkThe rapid uptake of AI across multiple sectors and capacity for continuous adaptation pose serious challenges to regulation of the technology. Although regulation aims to ensure the compliance of AI with ethical and productive societal contributions while maintaining innovative freedom, the United States federal government has provided limited regulatory leadership on the subject, consequently requiring states to develop individual policy approaches. Leaving this process to states creates the potential for gaps in legislative policies between governing bodies, inhibiting effective governmental addresses to an already difficult to regulate subject. Moreover, it can give rise to unforeseeable harms by AI products on economies, societies, and individuals.
This thesis leverages advanced document embedding techniques to analyze 469 proposed AI-related bills across 49 U.S. jurisdictions during the 2023 and 2024 legislative sessions. Vector based similarity measures are used to assess the diversity of policy issues within each jurisdiction and cohesion of addresses across jurisdictions. Machine learning models trained on the document vectors predict target features, including bill enactment or failure. The most accurate model predicts bill outcome with 76% accuracy. This model is utilized to predict the outcome of bills from 2024 for which outcome was determined after the time of data collection to explore the potential for practical application in legislative contexts. Finally, this study uncovers a statistically significant relationship between AI industry presence and the number of AI-related bill proposals by jurisdictions, suggesting industry influence on legislative efforts. These findings offer insight for ongoing policy discussions and provide the foundations for effective AI governance going forward.</p
Decomposing Idioms: Factors That Impact Perceived Idiomaticity
Full text linkThough prevalent in everyday language, idioms are notoriously difficult to define. This dissertation investigates factors that impact our conceptualization of idioms by addressing the challenge of defining idiomaticity as a cognitive construct. To this end, it contributes the first empirically tested description of the class idiom. Idioms are often operationalized as though they comprise a cleanly delineated class, in which a phrase either is, or is not, idiomatic based on the necessary and sufficient condition of noncompositionality. This is carried into psycholinguistic work investigating idiom processing and serves as the basis for several prevalent models of idiom comprehension. However, some propose that idioms exist on a continuum, with certain properties of idiomaticity moderating the degree to which phrases are perceived as idiomatic. Experiment 1 presents direct evidence demonstrating that idiomaticity is not a discrete construct, thereby resolving this point of contention. Instead, it shows that the mental category idiom is continuous, and membership may be based on prototype similarity. Experiment 2 investigates the relationship between perceived idiomaticity and several properties of idioms, finding that distributed idiomatic meaning, partial literality, and plausible dual idiomatic and non-idiomatic meaning are individually and collectively predictive of perceived idiomaticity and may serve as markers of idiom prototypicality. Overall, this work increases our understanding of the mental construct of idiomaticity, addressing long-standing assumptions about the mental representation of phrases and the access of idiomatic meaning, upon which models of idiom conceptualization and comprehension are predicated. Additionally, it raises methodological and theoretical concerns, urging for careful consideration of properties in experimental design as well as in the interpretation of experimental findings. More broadly, these findings have implications for theories of language processing, second language acquisition, natural language processing, and clinical linguistics. Thus, this study paves the way for a more nuanced, prototype-based account of idiomaticity, capable of addressing variation within the class idiom by recognizing and incorporating the continuum along which idiomatic phrases lie.</p
Three Essays on Trade, Environment, and Migration
Full text linkThis dissertation broadly studies impacts of globalization in two specific areas: environmental policy and migratory patterns. In my work, globalization refers to domestic tariff and industrial planning, changes in foreign market access, and technology diffusion through international trade.
In my first chapter, I study the environmental implications of optimal tariff and industrial policy. World governments and multinational institutions are implementing, largely, unilateral policies to correct for negative externalities exhibited by greenhouse gas emissions. These policies take two broad forms: pricing and subsides. When crafting policy, external economies of scale should be considered as they alter the effectiveness of optimal unilateral policy. First, I provide novel estimates of the external scale factor and the carbon di-oxide abatement elasticity. Second, I show that industries that exhibit stronger agglomeration effects also have higher pollution intensities across a variety of pollutants including carbon di - oxide. Policy makers should be cognizant of these effects when implementing industrial policy.
In my second chapter, I study the impacts of increased foreign competition in India on urban - rural migration. I use the Indian trade liberalization in the 1990’s to study the impacts of trade liberalization on the internal labor allocation of a country. Prior literature has found limited effects of changes in trade on the labor allocation in more developed countries. However, a literature is developing analyzing these effects in developing countries. I find that districts that were more impacted by trade liberalization experience a net loss of inter-district migrant workers and experience more intra-district migrants. These headline patterns are heterogeneous with gender, as well as origin and destination at the urban-rural level.
In my third chapter, I study how international trade acts as a mechanism for the diffusion of clean technology. Valuing the spillovers of clean technology subsidies in the wealthy world is important to understanding the value of this spending and has direct policy implications in efforts to curtail climate change. I explore how trade in intermediate goods is a channel for diffusion of lower carbon production. The results suggest that countries that import cleaner intermediate goods have cleaner domestic production. I aim to value the positive spillover benefits of clean technology spending for the rest of the world. Policy wise, there is debate between industrial policy and border adjustments in terms of targeting carbon leakage. To inform this debate, correctly evaluating these extra benefits is essential to mitigating global emissions.</p
Genetically Informed Approaches To Disentangle Relationships of Chronic Pain to Executive Functioning and Substance Use
Full text linkChronic pain is pain that persists for 3 or more months, often without discernible cause. There are many risk factors associated with chronified pain, including cognitive dysfunction and substance use. This dissertation uses multiple genetically informed methods to examine questions about genetic and environmental influences on chronic pain and its risk factors. Overall, these studies examine the phenotypic, genetic, environmental, and epigenetic relationships of chronic pain with executive functions and substance use. Study I found that chronic pain in young adults specifically relates to updating working memory, rather than to common executive function or mental set shifting, and that the association was entirely due to genetic effects. Study II demonstrates that the relationship between chronic pain and smoking may be due to underlying genetic risk, rather than a direct relationship, and that the reward pathway in the brain does not appear to be a significant mediator of the association. Study III shows that general chronic pain risk genetically relates to substance use disorder risk, and also shares additional associations with cigarette consumption and alcohol frequency. This dissertation establishes the importance of using genetically informed methods to interrogate epidemiological questions of interest.</p
Mercury Cycling in the Rocky Mountains: Sources, Fates, and Climate Change Impacts
Full text linkHumans have dramatically accelerated mercury (Hg) cycling in ecosystems across the globe due to anthropogenic activities. Depending on the speciation and concentration of Hg, exposure to this metal can cause a variety of health problems, which has led to significant research and regulation efforts to reduce the use and release of Hg. Despite these global and regional efforts, Hg will continue cycling at elevated levels for thousands of years due to its persistent nature. Continued cycling of Hg following its initial release is now of significant concern since around two-thirds of annual Hg emissions are from remobilized pools of Hg.
The goal of my research is to advance understanding of how mountain ecosystems cycle Hg and how that may change under a warming climate. First, I synthesized the recent literature on Hg cycling in mountain ecosystems with a focus on the U.S. Rocky Mountains. I identified primary Hg sources, storage, transformations, and losses, as well as impacts from climate change. I also highlighted important knowledge gaps and proposed future research priorities. Based on the gaps that I identified in my synthesis, I next characterized Hg inputs, storage, and bioaccumulation along an elevation gradient in the Colorado Rocky Mountains. Similar to past work conducted in the eastern U.S. Himalaya, and Tibetan Plateau, I found that elevation and tree cover are important drivers of Hg inputs and storage in mountain ecosystems. Unlike those past studies, however, I found that precipitation, rather than litterfall, dominated atmospheric inputs of Hg and was the primary driver of Hg bioaccumulation in terrestrial wildlife. Next, to assess the impact of climate change on the toxicity and bioavailability of Hg, I measured rates of methylmercury (MeHg) formation in alpine and subalpine wetlands under increasing sulfate concentrations. I found that MeHg formation in subalpine peatlands in the North Boulder Watershed of the Colorado Rocky Mountains are sulfate-limited. This watershed has experienced a 200 % increase in sulfate concentrations over the past 30 years—a pattern observed in over 100 high elevation watersheds globally—due to climate-driven sulfate weathering associated with thawing permafrost and rock glacier features. This increased export of sulfate may accelerate MeHg production and bioaccumulation in sulfate-limited high elevation watersheds. Finally, synthesizing information on Hg inputs, storage, and losses, I characterized the sink-source behavior of alpine and subalpine zones in the North Boulder Watershed to better constrain the role that mountain ecosystems play in cycling legacy Hg pools. I found that these regions act as sinks for Hg, however, major uncertainties exist with regards to losses via evasion. This factor is particularly relevant for the coniferous subalpine zone. My findings highlight the importance of better constraining losses of Hg in evasion from soil and snow surfaces to more accurately quantify the sink-source nature of mountains regions currently, as well as under future warming conditions. Altogether, the results of this body of research advance our understanding of the critical role that mountain ecosystems play in the global Hg cycle and underscore key priorities for future research to address remaining uncertainties, particularly in the context of climate change.</p
Nonanalyticities in the Time Evolution of Unconventional Superconductors
Full text linkDynamical Quantum Phase Transitions (DQPTs) are nonanalyticities in the Loschmidt echo, a quantity that characterizes the time evolution of quantum systems. These are analogous to thermal phase transitions, which are nonanalyticities in the thermal partition function. Over the past decade, DQPTs have been shown to have a close relationship with the equilibrium phases of quantum systems. DQPTs can serve as a probe of the underlying quantum critical points of a system.
In this thesis, we explore how DQPTs can occur in superconductors. We analytically show that DQPTs can occur in topological superconductors but not in the topologically trivial s-wave superconductor. We extend this analysis to study the spectral form factor, which is a related quantity that tells us about the time evolution of systems. We see how the spectral form factor of unconventional superconductors can have nonanalyticities, whereas that of the s-wave superconductor is featureless. These nonanalyticities arise due to the nontrivial structure of the superconducting gap function in momentum space, which in turn result from the symmetries of the Cooper pair wavefunction and the underlying lattice. We propose a method by which the spectral form factor can be measured if the superconducting Hamiltonian is simulated using qubits realized as Anderson pseudospins.
We find that the Schwinger-Keldysh mean field formalism is insufficient to evaluate these nonanalyticities in superconductors, and therefore develop a generalized mean field theory for this purpose. We present a simple model of a flat-band superconductor for which we can explicitly verify the validity of our generalized mean field theory.</p
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