50107 research outputs found
Sort by
Supplemental Data and Code for Geometrically Frustrated Assembly at Finite Temperature: Phase Transitions from Self-Limiting to Bulk States
No full textMarkov chain Monte Carlo code used to simulate finite-temperature phase behavior of lattice model of geometrically frustrated assembly. Example input script and parameters, along with output data, is provided for each of the observed equilibrium phases.Geometric frustration is recognized to generate complex morphologies in self-assembling particu- late and molecular systems. In bulk states, frustrated drives structured arrays of topological defects. In the dilute limit, these systems have been shown to form a novel state of self-limiting assembly, in which the equilibrium size of multi-particle domains are finite and well-defined. In this article, we employ Monte Carlo simulations of a recently developed 2D lattice model of geometrically frus- trated assembly [1] to study the phase transitions between the self-limiting and defect bulk phase driven by two distinct mechanisms: (i) increasing concentration and (ii) decreasing temperature or frustration. The first transition is mediated by a concentration-driven percolation transition of self-limiting, worm-like domains into an intermediate heterogeneous network mesophase, which gradually fills in at high concentration to form a quasi-uniform defect bulk state. We find that the percolation threshold is weakly dependent on frustration and shifts to higher concentration as frus- tration is increased, but depends strongly on the ratio of cohesion to elastic stiffness in the model. The second transition takes place between self-limiting assembly at high-temperature/frustration and phase separation into a condensed bulk state at low temperature/frustration. We consider the competing influences that translational and conformational entropy have on the critical tem- perature/frustration and show that the self-limiting phase is stabilized at higher frustrations and temperatures than previously expected. Taken together, this understanding of the transition path- ways from self-limiting to bulk defect phases of frustrated assembly allows us to map the phase behavior of this 2D minimal model over the full range of concentration.Work Supported by: NSF-2028885 & 2349818N
Estimating the Change in Expected All-Cause ED Hospitalizations During the COVID-19 Pandemic in Massachusetts
No full textThis study investigates the impact of the COVID-19 pandemic on Emergency Department (ED) visits resulting in hospital admissions across Massachusetts, stratified by diagnosis. We hypothesized that the pandemic altered both seasonal patterns and overall hospitalization levels, with varying effects across disease categories.
Weekly ED admission counts from January 2019 through January 2025 were obtained from the Massachusetts Department of Public Health. These data were stratified into nine ICD-10-based categories: cardiovascular diseases, digestive diseases, infectious diseases, infectious respiratory diseases, injuries, pneumonia, renal diseases, other respiratory diseases, and other diseases. This allowed us to examine cause-specific disruptions in ED utilization over time.
To estimate deviations from expected admission patterns, we adapted statistical methods used in public health to assess excess mortality during emergencies. Expected admission levels were modeled under non-pandemic conditions to identify deficits during the pandemic. Three temporal periods were analyzed: pre-pandemic, pandemic, and post-pandemic.
We used the excessmort R package to fit Poisson and mixed-effects models to the weekly counts for each category. These models captured smooth trends and seasonality while accounting for overdispersion and correlation. Generalized linear models (Poisson and quasi-Poisson) were used to estimate fixed temporal effects, while generalized linear mixed models included random effects to account for within-category correlation over time.
Findings revealed heterogeneous disruptions across categories. The most severe and sustained deficits were observed for pneumonia, respiratory diseases, and the “other” category. In contrast, cardiovascular and injury-related admissions declined sharply early in the pandemic but showed partial recovery. These results highlight the uneven impact of the pandemic on acute care utilization, shaped by disease-specific urgency, public health responses, and healthcare system strain, consistent with prior research on indirect effects and healthcare prioritization during public health emergencies.Master of Science (M.S.
DATA-DRIVEN ADAPTIVE HMI DESIGN: LEVERAGING MULTIMODAL DATA FOR SAFER DRIVING
No full textIn the domain of traffic safety, the Human-Machine Interface (HMI) plays a critical role in modern vehicles, enhancing the driving experience, promoting safety, and facilitating communication between drivers and their vehicles. The objective of the dissertation is to propose a unified framework for designing adaptive HMIs that leverage multimodal data, including semantic, contextual, and vehicle kinematic features, to improve drivers’ takeover experience and support driver awareness.
The first component of this work investigates the role of HMI design, specifically its modality, specificity, and timing, on driver performance during takeover situations. A driving simulator study revealed that HMIs with multimodal warnings and high specificity significantly improved driver takeover performance, reducing off-road glances and enhancing speed control.
The second component addresses the variability in driver behavior during Level 2 (L2) automation. Using clustering algorithms on vehicle kinematic data (e.g., speed, acceleration), two distinct driver groups were identified: variable drivers and stable drivers. Variable drivers exhibited higher crash rates and longer response times to auditory warnings, whereas stable drivers maintained more consistent speed control. These insights emphasize the need for personalized adaptive HMIs that accommodate different driver characteristics.
The third component introduces a two-stage latent complexity framework to capture and model roadway complexity for crash density prediction. By integrating semantic, contextual, and vehicle kinematic features, the framework generates hidden contextual representations that improve predictive performance. Analysis shows that incorporating these latent complexity features enhances the crash density prediction model performance, achieving an improvement in predictive accuracy from 87.98% to 90.46%.
Together, these components form a holistic approach to data-driven, adaptive HMIs. By leveraging multimodal data from semantic, contextual, and vehicle kinematic features, the framework enables personalized, predictive, and context-aware interfaces that support control transitions and adapt to complex roadway environments, ultimately enhancing safety and system intelligence in automated driving.Doctor of Philosophy (Ph.D.
TUNABLE NONRECIPROCAL COUPLING BETWEEN TWO QUANTUM MODULES
No full textNonreciprocity is an important property for building interesting and complex quantum systems and for their applications to quantum information processing. In this thesis, we show a low-loss waveguide circulator, a nonreciprocal device, and the understanding about its internal structure as multi-mode hybrid quantum system. Furthermore, we show the circulator integrated with superconducting niobium cavities, and the tunable nonreciprocal interactions between the intra-cavity photons due to coherent coupling to chiral internal modes. %between the intra-cavity photons. which can be presented through effective non-Hermitian dynamics of this system.
Based on this platform, we integrate superconducting transmon qubit into the system and explore the nonreciprocal dispersive-type interaction between a transmon qubit and a superconducting cavity, and we introduce a general master-equation model to discribe the observed qubit-cavity dynamics agnostic to the intermediary system. This study demonstrates an example of a new class of quantum nonreciprocal phenomena beyond typical non-Hermitian Hamiltonians and cascaded systems.U.S. Department of Energy, Office of Science, National Quantum Information Science Research Centers, Co-Design Center for Quantum Advantage under contract DE-SC0012704.
Army Research Office Grant No.~W911-NF-17-10469.Doctor of Philosophy (Ph.D.
THE INFLUENCE OF LEVEL OF CHILD CHALLENGING BEHAVIOR ON PARENTS’ ENGAGEMENT IN SCHOOL: EXAMINING MOTIVATIONS AND ACTIVITIES
No full textResearch shows that parent engagement can lead to improved behavior, however there is emerging research that suggests a child’s behaviors may influence parent engagement. Collective findings suggest that for at-risk populations of children who could benefit the most from proactive and sustained engagement, parents may engage in a reactive way, less frequently, or not at all. This study explored the similarities and differences between parents of children with low, medium, and high levels of challenging behavior on the cognitive motivators and behavioral activities of parent engagement in school. Parents (N=570) of children ages 4-17 completed the Strengths and Difficulties Questionnaire, the Family Involvement Questionnaire – Short Form, and the Parent Involvement Project – Parent Questionnaire. Parents of children with low levels of challenging behavior reported significantly low home-school conferencing compared to parents of children with high levels of behavior. Parents of children with low levels of behavior reported significantly high school-based involvement compared to parents of high levels of behavior. Analyses confirmed an inverse relationship across all levels of challenging child behavior and parental self-efficacy, with lower levels of challenging behavior associated with higher self-efficacy. Parent’s perceptions of general school invitations and life context variables of time and energy and skills and knowledge were significantly higher for parents of children with low levels of challenging behaviors compared to parents of children with medium and high levels. Role construction was significantly different between parents of children with low and high levels of challenging behavior, with high levels of behavior associated with a decreased sense of parental responsibility for educational outcomes. No significant differences were found for home-based involvement, child, or teacher invitations to engage. Parent education, parent gender, child age, and number of services were significantly correlated with the cognitive and behavioral aspects of parent engagement.Doctor of Philosophy (Ph.D.
Source Data for Michael S. Dimitriyev, Benjamin R. Greenvall, Rejoy Matthew, & Gregory M. Grason, "Not even metastable: Cubic double-diamond in diblock copolymer melts"
No full textSource data and code to reproduce the results published in Michael S. Dimitriyev, Benjamin R. Greenvall, Rejoy Matthew, & Gregory M. Grason, "Not even metastable: Cubic double-diamond in diblock copolymer melts"N
LIGHTING XANADU: THE PROCESS OF STRIVING TO DESIGN A PARADISE WITHIN THE CONSTRAINTS OF FEASIBILITY
No full textThis thesis document provides an overview of the lighting process of the musical Xanadu, including information about pre-preparation, paperwork, collaboration, and execution of the lighting design. It also comments on the importance of the process of producing theater in an academic setting, while recognizing the bounds of the resources we have to work with.Master of Fine Arts (M.F.A.
The Sedentary Shift: Is Living Off-Campus a Barrier to Physical Activity for Undergraduate Students?
No full textPhysical activity (PA) is a critical component of student health, playing a central role in both immediate wellbeing and long-term health. Off campus housing may present challenges that hinder students’ ability to engage in PA like exercise. Existing literature examines various aspects of PA and health among college students, which involve campus walkability, social support, and lifestyle activities. However, research does not adequately address the unique factors influencing PA levels among off-campus students such as housing location, accessibility, exercise preferences, and environmental and social barriers. This thesis explores the knowledge gap by investigating the impact living off campus has on the PA behaviors among undergraduate students attending a highly residential northeastern university. A survey of off-campus students queried levels and types of PA, factors associated with the mode of transportation and distance to campus, and qualitative feedback surrounding specific experiences, barriers, and needs and preferences of participants living off campus. The survey also examined student engagement with university fitness facilities, such as RecWell, and their role in supporting or hindering PA. Findings aim to enhance the understanding of lifestyle and environmental influences on PA among off-campus college students. The thesis will be of interest to those concerned about
institutional support for PA among undergraduate students, particularly for the off-campus population.Bachelor of Science (B.S.
Using Culturally Tailored Text Message Reminders and Group Support Engagement to Improve the Self-Management of Type 2 Diabetes among African Americans
No full textBackground: African Americans are at higher risk of developing type 2 diabetes and are disproportionately burdened with significantly higher hospitalization and mortality rates from diabetes complications than other populations.
Purpose: The purpose of this DNP project was to implement a culturally tailored intervention among African American participants with type 2 diabetes to increase participants’ knowledge and overall clinical outcomes.
Methods: This DNP project was conducted at a free clinic in Worcester, Massachusetts, targeting African American adults aged 18 and older. Participants received bi-weekly text message reminders and attended three monthly educational sessions. The outcomes measured included pre- and post-intervention self-reported A1C scores, pre- and post-intervention DSMQ scores, and participants’ satisfaction survey.
Results: Seven African American adults with type 2 diabetes, aged 45 to 65, completed the intervention. The DSMQ results indicate an improvement in blood glucose monitoring at home from 42,9% to 85.7%, medication adherence from 42.9% to 100%, adherence to providers’ dietary recommendations from 28.6% to 100%, increased physical activity from 14.3% to 71.4%, and maintaining doctors’ appointment from 85.7% to 100%. The post-intervention A1C mean scores showed improved glycemic levels from 8.30 to 6.25, with a standard deviation of 1.91. The results indicated significant participant satisfaction.
Conclusion: This intervention led to increased diabetes knowledge and improvements in glycemic control among participants. The project resulted in an overall improvement in nutritional outcomes, medication adherence, physical activity, and self-care behaviors.
Keywords: Type 2 diabetes, diabetes self-management education, culturally tailored intervention, exercise, minority groups, African Americans, and lifestyle modificationsDoctor of Nursing Practice, Family Nurse Practione
Skin Cancer Teaching Intervention
No full textBackground: Skin cancer is a prevalent and often overlooked disease in today’s population. There is a knowledge deficit among the young adult population regarding skin cancer identification, prevention, and causes. This age group engages in risky sun-related behaviors that have the potential to increase their skin cancer risk for life. The purpose of this project was to increase skin cancer knowledge among young adults.
Methods: The DNP project employed a pretest-posttest design incorporating an evidence-based educational intervention. This educational intervention was implemented at a small college located in Western Massachusetts during one class period, which lasted approximately an hour and a half. The project design entailed administering pretest-post test surveys that included questions about skin cancer awareness and sun damage knowledge alongside a demographic questionnaire.
Results: Forty-five senior nursing students participated fully in this intervention, including completed pre- and post-intervention surveys. Skin cancer knowledge was expected to increase by 15% or more after the intervention. The actual increase in skin cancer and sun prevention knowledge was 8% post-intervention, as shown through the improvement in post-intervention survey scores.
Conclusion: Skin cancer teaching is essential for young adults. With early intervention, there is the potential to prevent skin cancer in members of this population and raise awareness of skin cancer signs.
Keywords: skin cancer, young adults, identification, causes, and preventionDoctor of Nursing Practice, Family Nurse Practione