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

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Hydrodynamics and Sediment-Transport Pathways along a Mixed-Energy Spit-Inlet System: A Modeling Study at Chincoteague Inlet (Virginia, USA)
(Journal of Marine Science and Engineering, 2023-05-18) Georgiou, Ioannis Y.; Messina, Francesca; Sakib, Md Mohiuddin; Zou, Shan; Foster-Martinez, Madeline; Bregman, Martijn; Hein, Christopher J.; Fenster, Michael S.; Shawler, Justin L.; McPherran, Kaitlyn; Trembanis, Arthur C.
Tidal-inlet systems are dynamic features that respond to short-term (e.g., storms) and longer-term processes (e.g., sea-level rise, changes in tidal prism). The Chincoteague Inlet system, located along the northern Eastern Shore of Virginia (USA), is a dynamic coastal complex that experiences rapid change associated with sediment redistribution and a shifting inlet throat due to the southern elongation of adjacent Assateague Island. In this study, a numerical model based on Delft3D with coupled flow–waves, multiclass sediment transport, and morphologic feedback was developed to quantify the hydrodynamic and geomorphic controls within this rapidly evolving inlet–spit system and to develop a more comprehensive understanding of regional to local controls on sediment-transport pathways. Model results show that most of the sand transport along southern Assateague Island is sequestered nearshore and proximally in deeper sinks within Fishing Point, and, of that, only finer sand sizes are transported around the spit, confirming previous analysis and hypothesis. The model also showed that sand transport toward the south increases along Wallops Island and quantified spatially explicit transport trends for selected sediment classes, revealing that coarser sediment bypassing is a punctuated process that is proportional to storms.
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‘I’m Scared to Death to Try It on My Own’: I-Poems and the complexities of religious housing support for people on the US sex offender registry
(Anti-Trafficking Review, 2023-04-26) Leon, Chrysanthi S.; Buckridge, Maggie; Herdoíza, Michaela
In the US, street-based sex workers and people convicted of sex offences are both ‘special populations’, often with additional conditions of community supervision. People convicted of sex offences experience a complicated mix of assistance and surveillance as they re-enter society post-conviction, including numerous restrictions on housing and employment. As a result, they are especially likely to experience homelessness upon release. This article uses I-Poems drawn from interviews with volunteers and professionals who navigate the obstacles to re-entry that govern people on the sex offender registry. We focus on people with religious affiliations (n=38) who provide urgent support during the re-entry process. I-poems are a feminist technique for analysing qualitative data that forefronts the voices of people not often heard and distils complex experiences into accessible narratives. While few in our study overtly exploited re-entering persons on the registry, most support was problematic in subtler ways: we found that re-entering registrants are asked to accept constrained choices involving labour, religious participation, and romantic and other personal relationships in order to receive assistance. Given the secondary stigma attached to work with people convicted of sex offences, and the obscurity within in which many of these religiously-affiliated programmes operate, I-Poems both humanise and reveal the complexities of coercion, religious calling, and supportive housing.
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Calculating the Environmental Impacts of Low-Impact Development Using Long-Term Hydrologic Impact Assessment: A Review of Model Applications
(Land, 2023-03-04) Cai, Zhenhang; Zhu, Rui; Ruggiero, Emma; Newman, Galen; Horney, Jennifer A.
Low-impact development (LID) is a planning and design strategy that addresses water quality and quantity while providing co-benefits in the urban and suburban landscape. The Long-Term Hydrologic Impact Assessment (L-THIA) model estimates runoff and pollutant loadings using simple inputs of land use, soil type, and climatic data for the watershed-scale analysis of average annual runoff based on curve number analysis. Using Scopus, Web of Science, and Google Scholar, we screened 303 articles that included the search term “L-THIA”, identifying 47 where L-THIA was used as the primary research method. After review, articles were categorized on the basis of the primary purpose of the use of L-THIA, including site screening, future scenarios and long-term impacts, site planning and design, economic impacts, model verification and calibration, and broader applications including policy development or flood mitigation. A growing body of research documents the use of L-THIA models across landscapes in applications such as the simulations of pollutant loadings for land use change scenarios and the evaluation of designs and cost-effectiveness. While the existing literature demonstrates that L-THIA models are a useful tool, future directions should include more innovative applications such as intentional community engagement and a focus on equity, climate change impacts, and the return on investment and performance of LID practices to address gaps in knowledge.
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Recessive TMOD1 mutation causes childhood cardiomyopathy
(Communications Biology, 2024-01-02) Vasilescu, Catalina; Colpan, Mert; Ojala, Tiina H.; Manninen, Tuula; Mutka, Aino; Ylänen, Kaisa; Rahkonen, Otto; Poutanen, Tuija; Martelius, Laura; Kumari, Reena; Hinterding, Helena; Brilhante, Virginia; Ojanen, Simo; Lappalainen, Pekka; Koskenvuo, Juha; Carroll, Christopher J.; Fowler, Velia M.; Gregorio, Carol C.; Suomalainen, Anu
Familial cardiomyopathy in pediatric stages is a poorly understood presentation of heart disease in children that is attributed to pathogenic mutations. Through exome sequencing, we report a homozygous variant in tropomodulin 1 (TMOD1; c.565C>T, p.R189W) in three individuals from two unrelated families with childhood-onset dilated and restrictive cardiomyopathy. To decipher the mechanism of pathogenicity of the R189W mutation in TMOD1, we utilized a wide array of methods, including protein analyses, biochemistry and cultured cardiomyocytes. Structural modeling revealed potential defects in the local folding of TMOD1R189W and its affinity for actin. Cardiomyocytes expressing GFP-TMOD1R189W demonstrated longer thin filaments than GFP-TMOD1wt-expressing cells, resulting in compromised filament length regulation. Furthermore, TMOD1R189W showed weakened activity in capping actin filament pointed ends, providing direct evidence for the variant’s effect on actin filament length regulation. Our data indicate that the p.R189W variant in TMOD1 has altered biochemical properties and reveals a unique mechanism for childhood-onset cardiomyopathy.
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Impact of Marine Heatwaves on Air-Sea CO2 Flux Along the US East Coast
(Geophysical Research Letters, 2024-01-02) Edwing, Kelsea; Wu, Zelun; Lu, Wenfang; Li, Xinyu; Cai, Wei-Jun; Yan, Xiao-Hai
Marine heatwaves (MHWs) are extremely warm ocean temperature events that significantly affect marine environments, but their effects on the coastal carbonate system are still uncertain. In this study, we systematically quantify MHWs' impacts on air-sea carbon dioxide (CO2) flux anomalies (FCO2′) in the Mid-Atlantic Bight (MAB) and South Atlantic Bight (SAB) from 1992 to 2020. During the longest MHW in both regions, oceanic CO2 uptake capabilities substantially decreased, primarily due to significant increases in the seawater partial pressure of CO2 (pCO2sea). For all cases, MHWs played a more significant role in driving pCO2sea changes in the MAB than the SAB, where non-thermal drivers dominated pCO2sea variability. In the MAB, weakened wind speeds related to wintertime atmospheric perturbations increase ocean temperatures and pCO2sea, further reducing CO2 uptake during winter MHWs. This work is the first to connect extreme temperatures to coastal air-sea CO2 fluxes. The reduction in CO2 absorption noted during MHWs in this study has important implications for coastal regions to act as continued sinks for excess CO2 emissions in the atmosphere. Key Points - Marine heatwaves (MHWs) primarily generated positive sea surface pCO2 (pCO2sea) anomalies in the Mid-Atlantic Bight (MAB) and South Atlantic Bight (SAB) but had a larger impact on air-sea CO2 flux anomalies in the MAB - Reduced wind speeds amplified MHW contributions during CO2 sink months and counteracted them during CO2 source months - In the MAB, wintertime atmospheric perturbations related to zonal shifts in the jet stream produce slower wind speeds which aid in generating air-sea heat flux type MHW events that ultimately reduce oceanic CO2 uptake Plain Language Summary The transfer of carbon dioxide (CO2) between the atmosphere and ocean is sensitive to sea surface temperature (SST) changes because warmer SSTs increase the sea surface partial pressure of CO2 and reduce the ocean's ability to absorb CO2 from the atmosphere. It is, therefore, conceivable that marine heatwaves (MHWs), which are extremely warm ocean temperature events, could modify how carbon moves between the ocean and the atmosphere. This study provides the first attempt to evaluate the impacts of MHWs on the air-sea CO2 flux (FCO2) anomalies along the US East Coast, encompassing the Mid-Atlantic Bight (MAB) and South Atlantic Bight (SAB) during 1992–2020. Both regions experienced reduced CO2 absorption in response to the longest MHWs in each region. These extreme temperatures had a larger impact on CO2 absorption in the MAB compared to the SAB, where non-temperature factors were more influential. The coastal ocean plays an important role in helping to mitigate human-induced climate change by absorbing excess CO2 from the atmosphere. As such, the demonstrated reduced absorption of the ocean associated with MHWs in this study, which might also apply to other coastal locations, has vital implications for the efficiency of the ocean in offsetting global warming impacts.