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Within and Between-Person Variability in Glycemic and Lipidemic Responses to High-Fat and High-Carbohydrate Meals
No full textBackground: Understanding postprandial metabolic responses to nutritional inputs is important for developing effective dietary recommendations and preventing chronic diseases. While between-person variability in postprandial glucose and lipid responses is well studied, within-person variability is not fully understood. Lifestyle factors such as dietary quality, physical activity, sleep, and stress, may contribute to this variability. This study aimed to investigate within- and between-person variability in postprandial glycemic and lipidemic responses to high-carbohydrate and high-fat meals, and to explore associations between lifestyle behaviors and postprandial responses. Methods: Twenty participants were randomized to a high-carbohydrate or high-fat meal condition, where the assigned meal type was consumed at three separate timepoints. Eleven participants completed both conditions in a crossover design. Dietary quality was assessed using the Healthy Eating Index based on three 24-hour dietary recalls collected via the Automated Self-Administered 24-Hour (ASA-24®) Dietary Tool. Physical activity was assessed using Activities Completed over Time in 24 Hours (ACT-24) recalls and International Physical Activity Questionnaires (IPAQ), while sleep quality was evaluated through the Pittsburgh Sleep Quality Index (PSQI) and stress levels using the Depression, Anxiety, and Stress Scale-21 (DASS-21). Physical activity was also objectively measured using accelerometry (Fibion SENS). Continuous glucose monitors (Dexcom G7) recorded postprandial glucose at 0, 15, 30, 60, 90, and 120 minutes, while blood lipids were assessed via fingersticks at 0, 120, and 240 minutes. Incremental area under the curve (iAUC) was calculated using the trapezoidal rule. Intraclass correlation coefficients (ICCs) were used to compare within- and between-participant variability. Results: The ICCs revealed substantial within-person variability in metabolic responses, particularly after high-carbohydrate meals. For the high-carbohydrate meal condition, lower and negative ICC values (-0.171 for single measures and -0.412 for average measures) with 95% confidence intervals ranging from -0.603 to 0.339 and -3.040 to 0.507 respectively, suggested that individual responses were highly inconsistent across different time points, with between-person differences contributing minimally to the overall variance. This was further supported by the non-significant F-test for reliability (F = 0.708, p = 0.744). Following the high-fat meal, glucose iAUC values ranged from 0.0 to 4507.5 mg/dL × 2 h and TG iAUC values from 340.0 ± 588.9 to 12,960.0 ± 4817.9 mg/dL × 4 h. There was significant between-person variability in glucose (p = 0.002), but not TG (p = 0.68) following the high-fat meal. Poorer sleep quality was associated with lower glucose responses (rho = -0.509, p = 0.004). Conclusions: Findings highlight the importance of considering within-person variability as compared to the current popular focus on between-person variability. The observed heterogeneity in metabolic responses suggests the need for repeated measurements to improve individualized dietary recommendations
Qualitative Analysis of Clinical and Community Perinatal Providers’ Perceived Barriers to Equitable Care for Food Insecurity in Underserved Communities in Southern Nevada
No full textFood insecurity is prevalent among underserved communities and contributes to increasing maternal-child health disparities. The perinatal period from pregnancy through one year postpartum provides a critical window of opportunity to identify and address food insecurity (FI). However, barriers such as inadequate staffing, lack of institutional and community resources have prevented perinatal providers from offering equitable care for FI, defined as providing screening, referrals, and follow-up services. The Social Ecological Model (SEM) is a framework that observes concepts at multiple levels, including (i) individual, (ii) interpersonal, (iii) institutional, (iv) community, and (v) policy. The objective of this study is to understand barriers perceived by perinatal providers to implement screening, referring, and following up strategies for food-insecure pregnant people and children living in underserved areas through the lens of the SEM. This qualitative study used a phenomenological approach to interview 15 perinatal providers working in underserved communities in Southern Nevada. Qualitative thematic analysis guided by the SEM identified key themes. This study identified barriers at the individual provider level such as a lack of perinatal provider knowledge and education on FI; at the interpersonal level such as a patient’s hesitancy to reveal sensitive information to providers; at the institutional level such as a lack of standard procedures to conduct screening, referring, and following up; and at the community and policy levels such as organizational capacity and historical distrust of healthcare systems as obstacles to offering equitable care for FI in perinatal settings. This study documented critical factors to improve implementation of screening, referring, and following up strategies, such as incorporating FI trainings for providers and increasing connections between clinical and community perinatal providers. Utilizing the created recommendations may promote equitable care for FI within clinical and community perinatal settings
Associations Of the Medicaid Expansion Policy with Racial/Ethnic Disparities in Breast Cancer Screening and Treatment
No full textBackground and Aim. This dissertation examines Medicaid expansion’s effect on breast cancer (BC) screening and treatment disparities in two Medicaid-expanding states (MES) that passed Medicaid expansion (New Jersey and Vermont) relative to two non-expansion states (NES) (Georgia and Wisconsin). It then compares the association of Medicaid expansion to other states that did not undertake this policy on various subgroups, such as minorities by race and ethnicity, income, and age groups. Black women still bear significant BC disparities due to untimely screenings, treatments, and deaths. Therefore, it is critical to investigate how socioeconomic status influences racial/ethnic disparity gaps, given that BC cases continue to rise in America (American Cancer Society, 2022d).Methods. This study provides reliable comparisons across states for healthcare professionals and policymakers, revealing how Medicaid expansion relates to various racial/ethnic subgroups receiving BC care. Thus, the analysis will differentiate these states by matching covariates in all four states that affect BC screening and treatment rates, including educational level, employment status, household income, and healthcare coverage. Thus, the association of Medicaid expansion with other potential influences will be more valid and accurate. 2012 and 2020 Behavioral Risk Factor Surveillance System (BRFSS) compares two MES and two NES. Last, the study applies a modified Andersen Framework Model to conceptualize associations of Medicaid expansion with BC screening and treatment across racial/ethnic groups. Results. The Intervention states show that Medicaid expansion, as a policy by itself, had comparable odds of receiving mammography screenings for both Black and women of other races relative to White women (OR = 0.67, 95% (CI): 0.45–1.01, p \u3c .0552); (OR = 1.13, 95% (CI): 0.77–1.66, p = .5430). Therefore, mammography screenings did not change for all races of women after Medicaid expansion took effect. However, Medicaid expansion had an overall positive impact on BC treatments. Relative to White women, Black women had about eight times higher odds of receiving BC treatments (OR = 8.07, 95% (CI): 1.12–58.36, p = .0386), whereas women of other races had comparable odds of receiving BC treatments (OR = 0.45, 95% (CI): 0.09–2.25, p \u3c .3289). Conclusion. The results indicate no support for Hypothesis 1 (H1) and Hypothesis 2 (H2) since Medicaid expansion did not improve mammography screenings for both Black and other races of women relative to White women. As a result, both Black and other races of women had comparable odds of mammography screening receipt in the past 12 months relative to White women, and the findings do not support (H1) and (H2). However, when looking at the Interaction between Race and Medicaid expansion, Medicaid expansion had a significant influence on BC treatments for Black women. Still, women of other races had comparable odds of receiving BC treatments, and Hypothesis 3 (H3) and Hypothesis 4 (H4) are partially supported
Autonomous UAV Swarm Formation Utilizing Gradient-Driven Contour Mapping for Radiation Source Localization
No full textThis thesis presents a drone swarm for radiation mapping to aid source localization. The Department of Energy advocates employing UAVs for this task, but existing approaches remain inefficient and impractical in real-world scenarios. Three custom drones are built and flight-tested. A control algorithm to follow a contour, a constant-intensity path, is designed using a gradient fit. By knowing the source’s direction, the drone swarm can fly in the optimal trajectory at every step, leaving nothing to assumption. A program is created that implements formation flight and autonomous navigation. It is tested via a software-in-the-loop simulation utilizing radiation sources and detectors modeled on their physical counterparts. Configurable missions are created to demonstrate contours for varying numbers of sources, relative locations, and strengths. The swarm, flying within a physics engine and using drones running production firmware, achieves contour mapping accuracy, efficiency, and reliability that surpass even purely theoretical results. Its detailed modular design simplifies physical deployment and enables extension to nonradiative signals
A Comprehensive Study on The Use of Sub-Coherent Self Heterodyne Linewidth Estimations
No full textA fundamental requirement for many precision spectroscopic applications is the development of stable lasers with narrow linewidths. However, accurately verifying laser linewidths becomes increasingly challenging as the linewidth decreases. In the field of frequency metrology, the delayed self-heterodyne technique has long been regarded as one of the most reliable and accessible methods for linewidth characterization, favored for its low equipment cost and reproducible results. Traditionally, self-heterodyne measurements employ an optical delay line significantly longer than the coherence length of the laser, with analysis performed via either the instantaneous power spectral density or the noise power spectral density. However, the use of long optical fibers introduces several limitations: substantial optical attenuation requiring amplification stages, and susceptibility to thermally induced Brownian noise, which can artificially broaden the measured spectrum. This work utilizes a short delay fiber – less than the laser’s coherence length can yield reliable and accurate linewidth measurements. The primary objective of this thesis is to provide a comprehensive methodology for extracting the laser linewidth from the power spectral density of a sub-coherence delay self-heterodyne signal, thereby offering an improved framework for precision laser characterization
An Analysis of The Influence of Human Disease Pathogens on Core Behaviors of The Black-Legged Tick
No full textIxodes scapularis, the black-legged or deer tick, is a vector for several different disease-causing microbes, including the causative agent of Lyme disease. As such, it is a major health concern for people living within its range in the eastern half of the United States, a habitation area that is increasing due to climate change. Despite its medical relevance as a disease vector, there is still much to learn about the basic behavior of these arachnids in the wild. Thus, the major hypothesis of this thesis is that ticks that are infected with specific human disease-causing microbes behave differently than those that are free of those pathogens. If the hypothesis is correct, this information might be used to develop more effective ways to control or prevent bites from pathogen-infected animals. My thesis analyzed 143 wild-caught ticks from 3 counties in Western Pennsylvania. I tested each tick for its activity over 1 day, a response to a stimulatory puff of carbon dioxide, and their respiration over 4 hours. After the behavioral analyses were complete, the ticks were molecularly characterized to ascertain if any human disease pathogens were present. Although 44 ticks were infected with Borrelia burgdorferi (the pathogen that causes Lyme disease), 16 were infected with Anaplasma phagocytophilum (the pathogen that causes anaplasmosis), 12 were infected Babesia microti (the causative agent of babesiosis), 2 were infected with Borrelia miyamotoi (the pathogen that causes Borrelia miyamotoi disease), 1 was infected with virus that causes Powassan virus disease, 8 were co-infected with two pathogens, and 2 were co-infected with 3 pathogens, none of these ticks displayed behaviors that were significantly different from the wild-caught animals that were free from the above pathogens. The implications of this study are that the ticks infected with specific human pathogens do not grossly affect their overall behavior, perhaps because the microbe load of the pathogens is small in comparison to the overall microbiota of animals in the wild. It is interesting to note that there are some reports of infection with human disease pathogens affecting the behavior of lab-reared ticks, so increasing the number of animals to assay in order to determine if more subtle differences occur would be a goal of future research
Bio-Inspired Electroactive Polymer (EAP) Sensors for Surface and Canal Flow Sensing in Dynamic Environments
No full textNature can often create some of the most efficient and elegant solutions to complex problems, and engineering stands to benefit greatly from these time-tested designs. One of the more sophisticated examples of this is the lateral line system in fish: a distributed network of superficial and canal neuromasts that enables aquatic species to detect fluid disturbances with remarkable precision. This dissertation leverages that biological framework to explore the potential of electroactive polymers (EAPs), aiming not just to replicate structure, but to emulate function.Two classes of EAPs form the basis of this work: electroactive plasticized polymer gels (EPPGs) and ionic polymer-metal composites (IPMCs). Both offer their own unique morphology and mechanoelectrical transduction (MET) mechanisms that make them well-suited candidates for mimicking the different components of an artificial lateral line. Their implementation is examined across two case studies: (1) a soft surface-mounted sensing skin inspired by superficial neuromasts, and (2) an internal sensor embedded within a synthetic canal structure, emulating the filtering behavior of canal neuromasts. The relationship between fluid dynamics, sensor geometry, and EAP response was explored through an integrated analytical, numerical, and experimental framework. The artificial skin successfully detected turbulent transitions at predicted thresholds, capturing nuanced spatial disturbances downstream. The canal sensor exhibited clear frequency-selective resonance around 90–110 Hz, matching analytical and simulation predictions. These findings demonstrate the feasibility of bioinspired EAP flow sensors and highlight opportunities to refine analytical models through experimental insights, enhancing real-world fluid sensing applications
Development of an Access Charge Framework for High-Speed Rail Incorporating Rail Replacement Costs and Dynamic Train Characteristics
No full textThis thesis develops a framework to determine track access charges for shared high-speed rail corridors, with a focus on rail replacement cost driven by train-induced loads. The method explicitly accounts for both static loads, resulting from axle weights, and dynamic loads that arise from train speed and track geometry, particularly curvature. Train characteristics such as axle load, operating speed, frequency of service, and number of wheels are integrated with track parameters, including curve radius, to calculate the total vertical load. These loads are used to estimate the cumulative tonnage threshold for rail replacement and the resulting service life of the track segment.The framework proceeds to calculate the total rail replacement cost, projects it to the end of the rail\u27s service life using inflation-adjusted rates and converts this cost into an equivalent annual amount. The annualized cost is then proportionally allocated to each train operator based on their calculated contribution to the cumulative rail loading. Finally, the per-trip access charge is calculated. A case study on the Palmdale–Burbank corridor planned to be shared by California High-Speed Rail (CAHSR) and Brightline West, demonstrates the framework’s application. Using publicly available and assumed operating data, the analysis shows that CAHSR trains contribute a greater share of total rail wear due to their higher axle loads, operating speed, and service frequency. Consequently, CAHSR is assigned a higher per-trip access charge than Brightline West. These results confirm that the proposed method provides an effective approach for allocating rail replacement costs based on actual infrastructure use
Grading in the Age of AI: Equity, Transparency, and the Role of Human Feedback
No full textAs artificial intelligence continues to shape higher education, automated grading software has become a more widely adopted—but often unquestioned—tool. While marketed as time-saving and objective, these platforms raise critical questions about equity, transparency, and pedagogical values. This presentation will draw on Neil Selwyn’s call for a “critical but balanced” lens in evaluating classroom AI tools and will examine how automated grading reshapes the fundamental practices of teaching and learning in higher education while also paying close attention to equity-related issues. Our session will share findings from a research project piloted in an English composition classroom. We will evaluate two commonly used grading platforms, comparing them to human feedback across dimensions such as linguistic diversity, writing style, and rhetorical complexity. Through a combination of literature review, a classroom trial, and student/instructor feedback, we explore how these tools may reinforce algorithmic bias or disadvantage multilingual and non-standard English writers. At the same time, we hope to identify moments where automation may support learning when used thoughtfully alongside instructor input
Advancing Children\u27s Mental Health in Nevada
No full textNevada ranks 51st nationally in youth mental health access and services, underscoring persistent shortages and disparities across the state. Nearly one in four youths aged 12–17 (23.5%) experienced a major depressive episode in the past year, and 73% did not receive treatment. Approximately 34,000 Nevada youths have reported suicidal thoughts—an urgent call for prevention and coordinated support.
During the 2024–2025 school year, 31.3% of Clark County School District students were chronically absent (missing 10% or more of school days), a challenge closely linked to mental health struggles and socioeconomic barriers.
This community forum provided an opportunity to generate dialogue and amplify practical strategies to enhance Nevada’s mental health support and improve outcomes for children statewide