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Physics-informed neural network for maximum detectable distance estimation in mobile gamma spectrometry
No full textAccurate estimation of the Maximum Detectable Distance (MDD) is critical for environmental remediation, nuclear incident response, and public safety. Conventional approaches assume stationary detectors and rely on computationally intensive simulations, limiting their applicability for mobile, real-time surveys. Mobile gamma spectrometry introduces additional complexities due to detector motion, variable acquisition times, and heterogeneous backgrounds. This study addresses the central question of how effectively a Physics-Informed Neural Network (PINN) can estimate MDD for mobile gamma spectrometry, while maintaining both accuracy and computational efficiency under dynamically changing environmental conditions. A multi-phase approach was employed, combining field data collection, computational modeling, and operational tool development. A hybrid PINN framework was developed, embedding radiation transport laws directly into the network’s loss function. By enforcing geometric spreading, attenuation, and boundary constraints, the PINN integrates first-principles physics with data-driven learning. The network produces physics-consistent predictions of MDD that account for variable background radiation, source shielding, and detector velocity. It was trained on field gamma counts from a 137Cs-contaminated Superfund site and validated using Monte Carlo N-Particle Transport Code (MCNP) simulations calibrated with measured attenuation coefficients. Field validation shows that the PINN consistently predicts MDD within 0.54 m of observed values, accurately modeling the combined effects of variable background, shielding, and source strength. It reproduces the expected decrease in MDD with increasing detector velocity and accounts for orientation-dependent variations. Sensitivity analyses show that acquisition time and detector speed are the dominant factors influencing detection capability. An MDD Calculator prototype demonstrates that these predictions can be directly applied in operational settings, enabling a real-time decision-support tool for remediation teams. By integrating radiation transport physics, machine learning, and operational constraints, this research establishes a physically interpretable, field-validated framework and represents a significant advancement over conventional simulation-based or purely data-driven approaches to mobile gamma spectrometry
Optical trapping of single dust in plasma - a micro-probe for in situ plasma diagnostics
No full textThis dissertation introduces optical trapping (OT) of single dust particles as a new diagnostic tool for probing low-temperature plasmas. By using focused laser beams to confine and transport individual microparticles, their trajectories can be analyzed to extract local plasma forces and electric fields with minimal perturbation. Two optical trapping systems were implemented: dual hollow-beam universal optical traps (UOTs) and loosely focused dual Gaussian-beam traps, both of which were integrated with a low-temperature plasma device, optical emission spectroscopy, and high-speed imaging. The technique was demonstrated in multiple plasma environments. Single particles were successfully trapped in atmospheric-pressure plasmas, including arc discharges, plasma jets, and dielectric barrier discharges. In RF plasmas, both transparent and absorbing particles, such as silica microspheres and carbon nanotubes, were confined and transported in three dimensions. Controlled transport was also extended to weakly magnetized plasmas, confirming the feasibility of single-particle diagnostics in magnetized environments. A major achievement of this work is the high-resolution mapping of radial electric fields in RF plasma sheaths. By moving a trapped particle across the sheath and applying a force balance analysis, detailed electric field profiles were obtained, with systematic variations observed as a function of gas pressure and applied RF voltage. Preliminary afterglow studies further revealed that dust particles retain significant charge after plasma extinction, producing accelerations beyond gravity and highlighting residual field effects. Collectively, these results establish optical trapping of single particles as a minimally invasive, versatile approach for sheath diagnostics, force and charge measurements, and magnetized plasma studies, opening new opportunities for both laboratory and applied plasma research
Advancing equity in adolescent mental health: A literature review and telehealth program design for school-based access
No full textAdolescents in the United States (U.S.) are experiencing a mental health crisis, with disproportionately high prevalence rates among marginalized youth. Approximately 1 in 5 adolescents are diagnosed with a mental, emotional, or behavioral condition (Panchal, 2024; Sappenfield et al., 2024). Yet, an estimated 40% (1.8 million) of adolescents aged 12-17 who experience a major depressive episode did not receive treatment (Substance Abuse and Mental Health Service Administration, 2024). This project examines existing barriers that hinder access to care for this population. While schools are the most common settings for adolescent mental health supports, more than half report difficulties with meeting the needs of students (Brown & Carrington, 2025). Addressing these obstacles are critical to improving outcomes and reducing the long-term impact of unaddressed mental health conditions. Using desk-based research, this comprehensive literature review explores the benefits, challenges, and effectiveness of school-based telehealth services. By drawing on existing studies and applying Bronfenbrenner’s Ecological Systems Theory and the Social Emotional Learning (SEL) framework, this review outlines core components and considerations involved in establishing school-based telehealth services for adolescents with evidence-based approaches to expand and improve access to care. In response to the identified problem, this project’s deliverable consists of a researched-based program manual and implementation guide to support the design of school-based telehealth services
Computational modeling of environment-driven molecular interactions in biological systems
No full textBiological molecules operate in environments that are heterogeneous and dynamic, which complicates the task of identifying the physical mechanisms that govern their behavior. This dissertation develops computational approaches that combine molecular dynamics and quantum chemical methods to examine how local environments shape structure, spectroscopy, and recognition across three representative systems: lipid bilayers perturbed by choline-based ionic liquids, solvatochromic dyes in ionic and mixed solvents, and G-quadruplex DNA bound to small-molecule ligands. In the membrane studies, all-atom simulations show how anion hydrophobicity and hydration state determine bilayer remodeling, ranging from lateral compression and headgroup reorientation to tail disorder and early pore formation. These atomistic insights explain how biocompatible ionic liquids modulate permeability and inform the design of safer delivery media. In the solvatochromism studies, explicit-solvent trajectories of the squaraine dye SO₃SQ are integrated with time-dependent density functional theory to resolve the structural and electrostatic contributions to spectral shifts. The workflow captures inhomogeneous broadening from ion pairing and polarization that cannot be reproduced by continuum models, creating a predictive link between spectral signatures and microenvironment distributions. In the nucleic acid studies, docking and long-timescale simulations coupled with free-energy calculations identify feasible binding modes of the porphyrin TMPyP4 to a c-MYC G-quadruplex. The results quantify the relative stability of end-stacking and intercalation, clarifying ligand recognition at atomic detail. Taken together, these projects demonstrate that environment-specific modeling is required to connect microscopic interactions with experimentally measurable properties. The protocols established here advance the predictive scope of computational chemistry and provide general strategies for studying membrane remodeling, solvatochromic response, and nucleic acid recognition in biologically relevant systems
Investigating the dissemination of zoonotic bacterium Edwardsiella tarda to aquaculture ponds and its adaptive response to antibiotic pressure
No full textBacterial diseases significantly impact U.S. catfish aquaculture. Edwardsiella tarda has historically been isolated from cultured fish species, and remains a zoonotic pathogen detected in disease cases across diverse hosts. This study investigated its potential dissemination pathways and adaptive capacity. Hi-C metagenome deconvolution of cormorant fecal samples showed that E. tarda can interact with gut microorganisms and mobile genetic elements, acquire resistance and virulence genes, and potentially be shed into ponds. Adaptive laboratory evolution under florfenicol exposure revealed the selection of mutations mainly in efflux- and stress-related genes, and resistance accompanied by fitness costs. Together, these findings identify E. tarda as a potential reservoir and vector of antimicrobial resistance in aquaculture, emphasizing its relevance to One Health by linking environmental, animal, and human health through resistance dissemination
The association between food insecurity, depression, and mental distress among adults in MS
No full textThis study investigated the relationship between food insecurity, depression, and mental distress among adults in Mississippi. Using the Centers for Disease Control and Prevention (CDC) PLACES dataset, a secondary quantitative cross-sectional analysis was conducted to explore interactions between the variables. Stepwise, linear regression models were used to assess the association between food insecurity and mental health outcomes, specifically focusing on mental distress and depressive prevalence at the county level within the state of Mississippi. Findings in this study showed that food insecurity was significantly associated with higher levels of both mental distress and depression at the county level. This study contributes to the growing body of literature advocating for comprehensive public health strategies that integrate food security with mental health initiatives. Further research may be necessary to explore the causal pathways underlying this relationship, particularly in populations disproportionately affected by food insecurity, especially in underserved communities like those in Mississippi
Datasets and script associated with S. B. Correa et al. 2025. Floodplain forests drive fruit-eating fish diversity at the Amazon Basin scale
Get PDFDatasets and script associated with S. B. Correa et al. 2025. Floodplain forests drive fruit-eating fish diversity at the Amazon Basin scale. File 1 (amazonfish_dist.csv) is a Comma-delimited file that includes occurrences of fruit-eating fish species per subbasin. File 2 (sp_frug_all.csv) is a Comma-delimited file that includes the scientific names of 29 fruit-eating fish species. File 3 (sp_frug_serrasal.csv) is a Comma-delimited file that includes the scientific names of 12 fruit-eating fish species of the family Serrasalmidae. File 4 (veget_data.csv) is a Comma delimited file that includes tree species richness per subbasin. File 5 (Script_analyses_plots_tables.docx) is a Microsoft Word file that includes R script for analyses, plots and tables included in the article
“We Don’t Have to Take Things so Seriously”: Humor, Queer Livability, and Homonormativity for a Rural English Language Arts Teacher
Get PDFExtending and challenging existing research about LGBTQIA+ life in rural educational contexts, this ethnographically informed qualitative study describes how Lulu—a white, cisgender, queer secondary English language arts teacher in a rural, public school in the Midwest—discursively constructed the functions of her humor with respect to teaching, queerness, and their interrelations. Drawing on social theorizations of humor, particularly queer theorizations of humor, this article argues that Lulu described her humor as having three functions: building relationships, facilitating learning, and opening possibilities for queerness. These findings illustrate tensions in that Lulu leveraged humor to build a livable, joyous career in which she was able to thrive as an out, queer person and teacher. However, her humor reinforced hetero- and homonormativities with respect to whiteness and assimilationism. These findings suggest that a queered understanding of normativity and humor can offer multiple paths forward for queer educators in and beyond rural English language arts classrooms
Leveraging the Public Health Infrastructure Grant to Support Alabama’s Workforce Training Needs Assessment
Get PDFBackground. In 2024, the Alabama Department of Public Health (ADPH) leveraged the Public Health Infrastructure Grant (PHIG) to support the development and training of Alabama’s public health workforce. Technical assistance was provided by the Region IV Public Health Training Center evaluation team to conduct ADPH’S Workforce Training Needs Assessment.
Purpose. The purpose of this Research Brief is to report key findings from this needs assessment and discuss implications for public health practice in the Deep South.
Methods. The evaluation team administered an online survey through Qualtrics to report key measures.
Results. Survey responses were received from 1,434 ADPH employees for a response rate of 54%. Demographic characteristics of survey respondents reflected the ADPH workforce. Mid- and senior-level staff rated the training topics of Health Equity, Public Health Sciences, and Community Partnerships as important but the need for training as only somewhat needed. Perceptions of support were high, but potential reasons for leaving the organization included low pay, unfavorable work environment, no opportunity for advancement, and burnout.
Conclusion. Results of this assessment will inform ADPH’s Workforce Development Plan, a key component of national accreditation. Assessments from multiple states may allow regional training centers to develop targeted trainings to meet needs across states (e.g., Deep South)
TEFL in Rural Schools of Uruguay: Designing a Network of Practice to Enhance Language Teaching
Get PDFThis article explores the program “Inglés Sin Límites” (English Without Limits), established in Uruguay to bridge teaching English as a foreign language (TEFL) instruction between urban and rural schools. As part of these efforts, the Godparents Project was created to develop a network of practices in which educators in rural schools could be supported in the teaching of English. Through the lens of a network of practice, we discuss the approaches used to support teachers as well as recommendations for expanding these practices and supporting rural teachers and students