Institutional Repository

The UDSpace Institutional Repository collects and disseminates research material from the University of Delaware.

  • Faculty, staff, and graduate students can deposit their research material directly into UDSpace. Faculty may use UDSpace to fulfill the University of Delaware Faculty Senate Open Access Resolution, and in many cases may use it to fulfill open access requirements from grant funding agencies.
  • Departments can use UDSpace to publish or distribute their working papers, technical reports, or other research material.
  • UDSpace also includes all doctoral dissertations from winter 2014 forward, and all master's theses from fall 2009 forward.

To learn more about UDSpace, and how you can make your research openly accessible to the public, visit our UDSpace Policies website.


Recent Submissions

Quantum computing for finance
(Nature Reviews Physics, 2023-07-11) Herman, Dylan; Googin, Cody; Liu, Xiaoyuan; Sun, Yue; Galda, Alexey; Safro, Ilya; Pistoia, Marco; Alexeev, Yuri
Quantum computers are expected to surpass the computational capabilities of classical computers and have a transformative impact on numerous industry sectors. We present a comprehensive summary of the state of the art of quantum computing for financial applications, with particular emphasis on stochastic modelling, optimization and machine learning. This Review is aimed at physicists, so it outlines the classical techniques used by the financial industry and discusses the potential advantages and limitations of quantum techniques. Finally, we look at the challenges that physicists could help tackle. Key points - Quantum algorithms for stochastic modelling, optimization and machine learning are applicable to various financial problems. - Quantum Monte Carlo integration and gradient estimation can provide quadratic speedup over classical methods, but more work is required to reduce the amount of quantum resources for early fault-tolerant feasibility and achieving an actual speedup. - Financial optimization problems can be continuous (convex or non-convex), discrete or mixed, and thus quantum algorithms for these problems can be applied. - The advantages and challenges of quantum machine learning for classical problems are also apparent in finance.
A comparative assessment of household power failure coping strategies in three American cities
(Energy Research and Social Science, 2024-05-19) Andresen, Adam X.; Kurtz, Liza C.; Chakalian, Paul M.; Hondula, David M.; Meerow, Sara; Gall, Melanie
Household power outage experiences vary based on outage characteristics and the household's ability to cope with a disruption. While disaster management scholarship has produced methods to predict where the most significant impacts of a hazard may occur, these methods do not anticipate secondary effects, such as those from power outages. This research is necessary as the expected risks associated with power outages will increase in the United States due to climate change, increasing electricity demand, and aging infrastructure. To understand households' power outage experiences, we collected 896 surveys from three cities in the United States: Detroit, MI; Miami, FL; and Phoenix, AZ. Participants were recruited through Amazon's Mechanical Turk (MTurk) service to complete a survey. We hypothesized that racial/ethnic minority groups, specifically non-white households and lower-income households experienced more frequent and prolonged power outages. We also hypothesized that the same groups were more likely to have experienced more significant adverse effects, such as throwing away perishable food and not receiving assistance. We found that non-white households in Phoenix and Detroit were more likely to experience longer outages than white households; however, this association was not present in Miami and was not statistically significant in any city. Income was not a major factor in predicting food waste or assistance received during the longest self-reported outage. Further assessments in varying geographical contexts and more generalizable samples are necessary to increase understanding of how households experience power outages.
Associations between anthropometry, body composition, and body image in athletes: a systematic review
(Frontiers in Psychology, 2024-05-13) Webb, Mary D.; Melough, Melissa M.; Earthman, Carrie P.; Katz, Sarah E.; Pacanowski, Carly R.
Introduction: Poor body image is a potent risk factor for disordered eating and eating disorders. Athletes are a population at increased risk for eating disorders despite reports of lower body image concerns compared to non-athletes. Body size and composition may influence an athlete’s susceptibility to poor body image. Methods: Five electronic databases (PubMed, Cochrane Library, PsycINFO, Web of Science, SPORTDiscus) were searched to systematically evaluate the literature regarding the association between body measures (i.e., anthropometric and body composition indicators) and body image in athletes. The systematic review was completed following PRISMA guidelines and 27 cross-sectional studies were identified for inclusion and evaluated using the Joanna Briggs Institute Critical Appraisal Checklist for Analytical Cross-Sectional Studies. Results: Studies differed in methodological assessment of anthropometry or body composition (i.e., self-reported versus researcher-measured), methods for evaluating aspects of body image, geographic location, and sport type. Higher body mass index (BMI) or percent body fat (%BF) was significantly associated with greater body dissatisfaction in 16 of 22 studies (72.7%). Positive associations between body measures and aspects of negative body image were most consistently observed among studies that assessed BMI based on self-reported heights and weights, while significant associations between body composition measures (e.g., %BF, fat mass, fat-free mass) were less common. Four of seven studies assessing relationships between BMI and an aspect of positive body image reported significant inverse relationships, while three revealed insignificant associations. Discussion: Overall, higher BMI and body fat were associated with body dissatisfaction among athletes. Future studies are needed to confirm these findings within focused populations and utilizing body composition methods (e.g., bioelectrical impedance techniques). Systematic review registration:, CRD42023446518.
Seeing without a Scene: Neurological Observations on the Origin and Function of the Dorsal Visual Stream
(Journal of Intelligence, 2024-05-11) Rafal, Robert D.
In all vertebrates, visual signals from each visual field project to the opposite midbrain tectum (called the superior colliculus in mammals). The tectum/colliculus computes visual salience to select targets for context-contingent visually guided behavior: a frog will orient toward a small, moving stimulus (insect prey) but away from a large, looming stimulus (a predator). In mammals, visual signals competing for behavioral salience are also transmitted to the visual cortex, where they are integrated with collicular signals and then projected via the dorsal visual stream to the parietal and frontal cortices. To control visually guided behavior, visual signals must be encoded in body-centered (egocentric) coordinates, and so visual signals must be integrated with information encoding eye position in the orbit—where the individual is looking. Eye position information is derived from copies of eye movement signals transmitted from the colliculus to the frontal and parietal cortices. In the intraparietal cortex of the dorsal stream, eye movement signals from the colliculus are used to predict the sensory consequences of action. These eye position signals are integrated with retinotopic visual signals to generate scaffolding for a visual scene that contains goal-relevant objects that are seen to have spatial relationships with each other and with the observer. Patients with degeneration of the superior colliculus, although they can see, behave as though they are blind. Bilateral damage to the intraparietal cortex of the dorsal stream causes the visual scene to disappear, leaving awareness of only one object that is lost in space. This tutorial considers what we have learned from patients with damage to the colliculus, or to the intraparietal cortex, about how the phylogenetically older midbrain and the newer mammalian dorsal cortical visual stream jointly coordinate the experience of a spatially and temporally coherent visual scene.
Role of Bacillus subtilis exopolymeric genes in modulating rhizosphere microbiome assembly
(Environmental Microbiome, 2024-05-14) Nishisaka, Caroline Sayuri; Ventura, João Paulo; Bais, Harsh P.; Mendes, Rodrigo
Background Bacillus subtilis is well known for promoting plant growth and reducing abiotic and biotic stresses. Mutant gene-defective models can be created to understand important traits associated with rhizosphere fitness. This study aimed to analyze the role of exopolymeric genes in modulating tomato rhizosphere microbiome assembly under a gradient of soil microbiome diversities using the B. subtilis wild-type strain UD1022 and its corresponding mutant strain UD1022eps−TasA, which is defective in exopolysaccharide (EPS) and TasA protein production. Results qPCR revealed that the B. subtilis UD1022eps−TasA− strain has a diminished capacity to colonize tomato roots in soils with diluted microbial diversity. The analysis of bacterial β-diversity revealed significant differences in bacterial and fungal community structures following inoculation with either the wild-type or mutant B. subtilis strains. The Verrucomicrobiota, Patescibacteria, and Nitrospirota phyla were more enriched with the wild-type strain inoculation than with the mutant inoculation. Co-occurrence analysis revealed that when the mutant was inoculated in tomato, the rhizosphere microbial community exhibited a lower level of modularity, fewer nodes, and fewer communities compared to communities inoculated with wild-type B. subtilis. Conclusion This study advances our understanding of the EPS and TasA genes, which are not only important for root colonization but also play a significant role in shaping rhizosphere microbiome assembly. Future research should concentrate on specific microbiome genetic traits and their implications for rhizosphere colonization, coupled with rhizosphere microbiome modulation. These efforts will be crucial for optimizing PGPR-based approaches in agriculture.