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Multi-Decadal Trends of Precipitation and Flooding in the James River Watershed
Full text linkThe trends in precipitation and flooding for the James River watershed are examined across the timeframe of 1951-2022. Precipitation is analyzed using spatial linear and quantile regressions across the watershed, which includes individually examining the trends across the warm months (April-September) and cold months (October-March). Floods are catalogued at selected stream sites to determine recent changes in frequency of events, as well as correlated with precipitation trends in terms of annual days above a threshold value. The James River watershed shows statistically significant positive trends for daily and extreme precipitation in the nearly the entire basin, especially during the warm months. Minor flood events at Richmond increased by 46% in the cold months and 131% in the warm months during 1979-2022 compared to 1935-1978. Precipitation accumulations preceding floods at Richmond were much higher during the warm months than the cold months. Richmond also displays a highly significant positive relationship between days with extreme precipitation and days above action or minor flood stage. The results indicate a strong potential for applying the analysis to other watersheds on a regional scale, which would provide implications of precipitation and flooding trends for a much larger area
Classifier Systems: A Quantitative Investigation of Their Distribution and Function in Mandarin Chinese
Full text linkClassifier systems constitute one of the most prominent features of East and South-East Asian languages (Li, 2013). Classifiers categorize referent nouns based on salient semantic features such as humanness, animacy, shape, or others (Aikhenvald and Mihas, 2019). The work described in this dissertation constitutes a thorough quantitative investigation of the distribution and function of classifiers in Mandarin Chinese and beyond. The results of the studies settle longstanding theoretical debates about the categorial nature of classifiers and contribute the first in-depth investigation of their communicative functions.Our main theoretical contribution is the development of a reliable methodology for objectively distinguishing between syntactic categories based on measurable differences in word distribution and functions. With this method, we settle the longstanding theoretical debate about the existence of multiple classifier types in Mandarin (Cheng and Sybesma, 1999; Li and Thompson, 1989; Li, 2013): we show that mensural classifiers should be distinguished from other types of classifiers based on their measurably distinctive distributions and functions. The thesis further investigates the cognitive and communicative functions of classifiers. We show that classifier-noun combinations are optimized to accommodate general communicative pressures (Blevins et al., 2017) of learning and processing, by balancing predictable and discriminative classifier-noun combinations. Previous work on noun classification implies that gender systems are inherently optimized to accommodate communicative pressures on human language learning and processing (Dye et al., 2018). The authors state that languages can make use of either grammatical (e.g., gender) or probabilisitic (pre-nominal modifier sequences) noun classification to smooth the uncertainty (entropy (Shannon, 1948)) of nouns in context. We show that a genderless language like Mandarin can rely on nominal classifiers in a comparable way: classifiers appear to play the same functional role as gender markers. Noun-classifier combinations are sensitive to same frequency, similarity, and co-occurrence interactions that structure gender systems. We also present the first study of the interaction between grammatical and probabilistic noun classification. Finally, this work explores the role of classifiers in post-nominal positions in Mandarin. Previous work suggests that linguistic elements in different positions will contribute differently to human learning and processing. Based on an artificial noun learning experiment, Ramscar (2013) shows how humans will tend to rely on prefixed elements to categorize nouns while suffixed elements will help them specify noun meanings. For nouns, meaning specification is especially useful if they carry more general meanings, i.e., for nouns that occur more frequently and in a broader range of contexts. An investigation of the differences between nouns occurring with pre- vs. post-nominal classifiers confirms these findings on natural language data. We find significant differences in the frequencies of the two types of nouns: pre-nominal classifiers tend to pair with lower frequency nouns to aid prediction, while post-nominal classifiers are associated with higher frequency nouns to refine their meanings. Additionally, sortal classifiers, which emphasize the intrinsic features of nouns, are predominantly used in pre-nominal positions for categorization. In contrast, mensural classifiers, known for their flexibility in quantifying nouns, are more commonly found in post-nominal positions to aid in meaning refinement. The implications of this work extend beyond language specific findings. By elucidating the complex interplay between classifiers and communicative efficiency, our study con- tributes to a deeper understanding of the cognitive processes underlying noun processing and learning. It also provides a framework to further investigate the role of classifiers in other classifier languages and structures
Ground-based Light Curve Follow-up Validation observations of TESS object of interest TOI 3777.01
Full text link“The objective of this research paper is to validate the findings on a potential exoplanet made by the Transiting Exoplanet Survey Satellite (TESS). Potential Exoplanet 3777.01 was found in 2021 and is located 1028.89 parsecs from Earth. In order to confirm that TOI 3777.01 is an exoplanet, data was gathered from the George Mason University 0.8m telescope. Once the data was collected, the Java astronomy program AstroImageJ was used to analyze the data. The transit method was used specifically, in which the light emitted from the candidate's host star is measured. When graphed through a light curve, a dip of the light emitted between the ingress and egress is an indicator of an exoplanet, as the planet orbiting in front of the star ends up blocking the emitted light of the host star, leading to the observed dip in the curve. To further enhance the effectiveness of the transit method, several functions of AstroImageJ were utilized in the analysis process, including plate solving, data reduction including dark subtraction and flat divisions, multi aperture photometry, stack editing and image calibration. Once the data was ready for construction, the emission of light from the target star was compared to other nearby stars, and a light curve was constructed (See Section 3). Based on the light curve, TOI 3777.01 can be classified as an exoplanet, as the brightness of the host star underwent a decrease and then an increase in transit, which is a clear indicator of an exoplanet orbiting a host star.
Examining the Effectiveness and Integrated Social Validity of Technology-Enhanced Family Coaching for Young Children with Autism Spectrum Disorder
Full text linkNaturalistic instruction strategies support increased opportunities for young children to practice attainment of communication and social emotional skills. This is critically important for young children with autism spectrum disorder, which is characterized by challenges in communication and social emotional development. Specifically, children with autism spectrum disorder can benefit from individualized, frequent opportunities to practice skills within the natural environment. While technology-enhanced family coaching has been studied in previous research and found to be an effective way to support parents to use naturalistic instruction strategies with fidelity, there is still more to learn about what works best for whom under what conditions. Therefore, this three-manuscript dissertation attempted to extend the existing literature through: (a) examining the literature on technology-enhanced family coaching for young children with autism, (b) designing and implementing a mixed-methods technology-enhanced family coaching intervention, and (c) integrating social validity data with visual analysis at multiple timepoints during the intervention. A systematic review following PRISMA guidelines added to the literature on the commonly reported elements of family coaching and revealed gaps regarding important components such as the population studied, coaching procedures, and social validity. Based on the results of this systematic review, I designed a mixed methods study that included a single case multiple baseline across strategies design which embedded a qualitative thematic analysis of open-ended social validity questionnaires. Participants included a mother, Elisabeth, and her five-year-old son Max (pseudonym). Max was receiving special education services for autism spectrum disorder and frequently demonstrated challenging behaviors during transitions. Coaching was provided via email and was delivered following a flexible schedule determined by Elisabeth. She chose the routine to target as well as the method of feedback (email) and goal behavior (transitioning activities). I observed a functional relation between the email feedback and Elisabeth’s use of NI strategies. Max also increased his responses to transition opportunities. Social validity results yielded three themes after qualitative analysis: (a) quality and effectiveness of coaching are most important, (b) family dynamics, caregiver well-being, and child well-being were impacted by Max’s behavior, and (c) expectations for coaching were focused on creating a positive overall home environment and interactions among all family members while requiring the least amount of extra time or tasks. Integration of single-case design (quantitative) and social validity (qualitative) data resulted in convergent and divergent themes. Implications for research and practice were provided
Teachers of Color and Racialized Experiences in Collaboration: A Phenomenological Study
Full text linkThis study was designed to shed light on the experiences of teachers of color in K-12 collaborative settings. Teachers of color hold students to higher academic standards, ensure culturally relevant and responsive curriculum and practices, advocate for and mentor students of color, and work toward social reform (Borrero et al., 2016). Additionally, research has found that the positive influence of racially minoritized teachers goes beyond those students who share a racial identity with them (Banerjee, 2018). However, although teachers of color are roughly 20% of the teaching profession, they are 25% more likely to leave the profession than their White counterparts who make up the remaining 80% (Grooms et al., 2021). This study aimed to understand the ways in which collaboration was racialized for teachers of color, what aspects of collaboration led to these racialized experiences, and how teachers of color perceived the negative consequences of these experiences. The study utilized critical race theory (CRT) as a theoretical framework and pulled from the following tenets of CRT: racism as ordinary in the everyday lives of people of color, the importance of intersectionality, anti-essentialism, and relying on the voices of people of color and their portrayal of their experiences as counternarrative. A qualitative phenomenological design was used, with data gathered from five participating teachers through writing prompts and semistructured interviews and analyzed via the thematic analysis method developed by Clarke and Braun (2017). The results indicated that the teachers of color experienced a lack of diversity in collaborative spaces that led to a lack of belonging, discomfort and opposition from colleagues, and the need to create safe spaces with fellow teachers of color. Some factors that made collaboration racialized for them were advocating for a culturally relevant curriculum, having to justify their practice, witnessing the negative impacts of schooling on students and families of color, additions to their workload, and experiencing microaggressions. Participants responded to racialized experiences by isolating themselves and withdrawing, and these experiences often led to thoughts of leaving a school site or the profession. The implications of this study include policy and practice suggestions pertaining to teacher preparation programs, professional development, and school culture and climate, as well as the start of a dialogue on creating safe spaces for teachers of color in collaboration and in schools
Fertility and Stress in Colonial Peru: A Transition Analysis-Based Paleodemographic Reconstruction of Birthrates and Female Health in the Lambayeque Valley Complex
Full text linkBioarchaeology has long sought paleodemographic insights on past populations but has been hindered by inherent limitations of traditional adult age estimation techniques. Continuing development of transition analysis helps transcend past issues in paleodemographic studies. Here, we apply transition analysis 3.0 (TA3) to adult human skeletal remains from the north coast of Peru in a paleodemographic reconstruction of crude fertility following Spanish colonization of the Lambayeque Valley Complex. We hypothesize that following conquest, the native Muchik communities of Mórrope (1535-1750 CE) experienced a more significant decline in birthrates than at Eten. Moreover, the application of TA3 will provide a more representative age-at-death distribution, than previous methods could allow. Age estimations based on dental development were calculated for 401 pre-adults and TA3 estimations generated for 176 adults. The well-established D30+/D5+ fertility estimation ratio demonstrates that the Mórrope community (D30+/D5+ = 0.8732) had lower fertility than Eten (D30+/D5+ = 0.5377), and that this difference is statistically significant (z = 5.0156; p < 0.0001). Also, D30+/D5+ values were calculated for Early/Middle and Middle/Late Colonial period subsamples at both sites. Birth rates in Eten seem to have increased over time while in Mórrope it was more gradual. Fertility is a function of female energetic status and biological stress. These findings parallel various independent lines of archaeological, skeletal, and contextual evidence indicating that Mórrope females endured significantly more stress compared to Eten. We fail to reject the hypotheses. Colonization did not lead to uniformitarian outcomes, even locally. We also argue that paleodemographic fertility estimations reveal an embodiment of Indigenous female socioeconomic marginalization. Transition analysis provided representative age-at-death distributions when compared to living populations. This work further advocates for the wider use of transition analysis in bioarchaeological studies
Enzymatic Activities of LTA4H Aminopeptidase Activity Modulators
Full text linkLeukotriene A4 Hydrolase (LTA4H) is a bifunctional zinc metalloenzyme with epoxide hydrolase (EH) and aminopeptidase (AP) activities at two overlapping catalytic sites. The AP activity has been identified to degrade the tripeptide proline-glycine-proline (PGP), a chemoattractant and biomarker of COPD. Recent advances have shown that although the bioavailable small molecule 4-methoxydiphenylmethane (4MDM) activates LTA4H hydrolysis of certain amino acids labeled with a p-nitroanilide (p-NA) reporter group such as Ala-p-NA, the PGP hydrolysis is not enhanced by the presence of 4MDM. Future directions are to identify other endogenous peptides cleaved by LTA4H, with the hypothesis that activation of LTA4H in general will have therapeutic effects. The field’s focus is to discover activators that are selective for the enzyme-substrate complex over the enzyme alone using Ala-p-NA as a reporter for enzyme modulation for comparison of therapeutic effects that might correlate with different enzyme mechanisms of LTA4H activation in the context of inflammation. The computational analysis of the new molecules docking to enzyme-substrate and substrate-free complexes from crystal structures in complex with the known activator 4MDM and the inhibitor bestatin may produce a model for predicting potential modulators. AC/IC50 assay results of the new molecules agreed with the computational analysis despite not being viable pharmaceutical candidates. Additionally, structural comparison between 4MDM, N-(pyridin-3-ylmethyl)aniline, and the new compound 2-[(4-Methylphenoxy)methyl]pyridine suggest the necessity of a methyl group to the diphenyl ether derivative structures for enhanced AP activity
Targeting the cholinergic synapse in development and disease
Full text linkThe cholinergic system is an essential modulatory neurotransmitter system in the mammalian brain responsible for regulating memory, attention, and overall cognitive function. This dissertation investigates several key components of the cholinergic system that are important for human neurodevelopment and disease. Chapter 2 investigates the non-enzymatic role of the T30 neuropeptide, a 30-amino acid peptide endogenously produced as a cleavage product of synaptic acetylcholinesterase. I show that T30 activates neural cell growth via the activation of the mammalian target of rapamycin (mTOR) pathway. The targeting of cholinergic nAChR, with small molecules or peptides, shows exciting promise in the development of drugs for treating human neurodegenerative and inflammatory disorders. Drug development however is often hampered by limitations in initial compound screening and target validation due to limitations in structural protein analysis and the computational limitations of crystallized modeling. In Chapter 3, I optimize protein painting-based mass spectrometry to find interaction sites between acetylcholine binding protein (AChBP) and various known nicotinic acetylcholine receptor (nAChR) ligands. Protein painting is thus presented as a novel strategy for drug development targeting nAChRs. Human immunodeficiency virus (HIV) continues to be a major global health problem with infected individuals at a heightened risk for cognitive decline. Moreover, almost half of all HIV-positive individuals also smoke tobacco products and studies have shown that smoking can worsen cognitive functions in HIV infected individuals. I examined interaction between the HIV glycoprotein gp120 and nicotine within human microglia (HMC3) cells. Microglia are a primary reservoir for HIV and have been recently shown to contribute to neuroinflammation during HIV infection. Results reported in Chapter 4 suggest an interplay between HIV protein gp120 and cholinergic signaling through nAChR in microglia alters mitochondrial dynamics, amyloid precursor protein processing and autophagy. These findings may offer insights into potential therapies targeting cholinergic signaling in HIV-associated neurocognitive disorders. By elucidating the underlying mechanisms of cholinergic signaling in synapse modulation, this work advances our understanding of neural health and disease
"No Man Left Behind" Conceptualizing Functioning and Increasing Access to Care for Male Survivors of Military Sexual Trauma
Full text linkMilitary sexual trauma (MST), or the perpetration of sexual harassment or sexual assault against a member of the military, continues to be a pervasive problem which affects many service members’ mental health (Fillo et al., 2018; SAPRO, 2021; Tannahill, 2020). Research on psychological sequelae and healthcare utilization among this population is limited and has primarily focused on female MST survivors (Monteith et al., 2019; Morris et al., 2014). Paper 1 presents an empirical analysis of sex differences in psychological functioning and patterns of healthcare utilization among survivors of MST. To reduce the influence of confounding variables sixty-one male survivors of MST were 1:1 propensity matched to female MST survivors on duty status, race, age, experiences of military sexual harassment, and experiences of military sexual assault. There were significant differences in PTSD scores and life satisfaction, wherein male MST survivors reported higher PTSD symptomatology and lower life satisfaction than matched female MST survivors. Veteran sex did not significantly predict VA healthcare satisfaction, VA healthcare use, or non-VA (i.e., civilian) healthcare use. Then, 2x2 between subjects factorial analysis of variance (ANOVA) were conducted to examine the influence of gender and mental healthcare access on mental health symptoms reported among MST survivors. There were no significant interaction effects between gender and mental healthcare treatment on mental health outcomes in our sample. However, treatment access was associated with higher PTSD symptoms, lower life satisfaction, and more alcohol use among the sample of MST survivors. Paper 2 presents an integrative literature review focusing on the barriers which prevent male MST survivors from accessing effective healthcare within the Veterans Healthcare Administration (VHA). The VHA is a national institution that operates separately from civilian healthcare, with its own training, mandates, and screening processes (Trivedi et al., 2011). This integrative literature review applies an ecological model of healthcare access (Zinzow et al., 2021) to the VHA. Barriers to accessing healthcare for male MST survivors are outlined at each level of the ecological model. Recommendations for remediating these barriers are provided and include military culture interventions, research initiatives, and policy recommendations for changes to the VA’s organization of MST care
Advanced Catalysts and Solid Oxide Electrochemical Cells Design for Aromatics And Renewable Fuel Production
No full textThis work is embargoed by the author and will not be publicly available until May 2026.Aromatics, in particular, benzene, toluene, and xylenes (BTX) are the essential building blocks for a wide range of applications in the chemical, food, cosmetic and pharmaceutical industries. Hydrogen is considered a promising alternative to fossil fuels because it is the cleanest fuel on the earth and has the highest gravimetric energy density among all chemical fuels (143 kJ kg−1). Highly efficient and environment-friendly production of aromatics and hydrogen has attracted world-wide attention due to the growing concerns about global warming and environmental issues. This dissertation offered two strategies to improve the production of aromatics and hydrogen. For aromatics production, molybdenum on zeolite catalysts as good candidates have been studied for the non-oxidative deprotonation of methane, also defined as methane dehydroaromatization (MDA) reaction. Nevertheless, this thermal catalytic process is limited by thermodynamics for higher conversion and by short lifetime for the Mo catalyst. The catalyst design strategies and process intensification strategies can be used to overcome hurdles. First, a trimetallic platinum–bismuth/molybdenum on zeolite structure (Pt-Bi/Mo-ZSM5) catalyst as a highly efficient catalyst is designed to promote conversion and yield by synergistic interaction with Mo and Pt-Bi alloys. To understand the synergy between Pt-Bi alloy and Mo species, the synthesis, microstructural analysis, performance evaluation, and mechanism exploration are performed. On the other hand, enhanced yield of aromatics and generating electricity simultaneously has been achieved through the integration of solid oxide cells (SOCs), especially membrane reactors, and trimetallic catalysts. The impact of co-generation effect on catalytic activity, electrochemical performances, and durability are systematically investigated. For hydrogen production, SOCs, especially protonic ceramic cells, also play important roles due to their low activation energy for proton conduction and dry hydrogen production. However, electronic leakage of electrolyte materials reduces fuel cell power output or faraday efficiency of electrolyzer. Fundamental solid-state electrolyte studies are discussed by combining the model and measured conductivities under various operating conditions to qualitatively analyze the leakage mechanism and further quantitatively predict the faradaic efficiency (FE). As a result, advanced catalysts and SOCs studied in this dissertation boost the aromatics and clean fuel production, further are expected to make huge contributions to decarbonize the chemical production industry and finally achieve carbon neutrality.2026-05-1