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.
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Recent Submissions
Obliquity Dominance in Early Pleistocene Sediments From the Antarctic Zone of the Southern Ocean (Indian Ocean Sector)
(Paleoceanography and Paleoclimatology, 2024-05-26) Billups, K.; Münch, B.; Garrioch, I.; Bradtmiller, L.
We constructed a record of percent biogenic silica (opal) accumulation at Ocean Drilling Program Site 745B located in the Indian Ocean sector of the Antarctic Zone of the Southern Ocean. The record spans the majority of the early Pleistocene (1.1–2.6 Ma). Orbital-scale sampling affords a look at the relative importance of obliquity versus precession variability through a time interval that is characterized by obliquity pacing in early Pleistocene δ18O records. Variations in the site's magnetic susceptibility record closely resemble those in the benthic foraminiferal δ18O stack (Lisiecki & Raymo, 2005, https://doi.org/10.1029/2004pa001071) and provide orbital-scale age control. Between 1.1 and 1.8 Ma, obliquity-related 41 kyr spectral peaks dominate with relatively little power at precession periods (23–19 kyr) in all records. Between 1.8 and 2.6 Ma, only the δ18O and magnetic susceptibility data display a distinct 41 kyr peak, while the opal lacks spectral power at any of the orbital periodicities. The lack of more pronounced precession-scale variations in the two proxy records is consistent with observations in foraminiferal δ18O records. A low or absent response to precession in these records appears to be due to environmental control. Lack of orbital forcing in the opal record before 1.8 Ma may reflect both a more southerly location of the polar frontal zone with respect to the site, and thus the site's position outside the region of wind-driven upwelling, and/or upwelling waters undersaturated with respect to silica prior to the establishment of the opal belt at about 2 Ma.
Traditional social learning predicts cyber deviance? Exploring the offending versatility thesis in social learning theory
(Behavioral Sciences & the Law, 2024-05-20) Zhou, You; Liu, Weidi; Lee, Claire; Xu, Boyang; Sun, Ivan
Social learning theory has been widely implemented to understand cyber deviance. Nevertheless, the antecedent scholarship homogenously nested in the perspective of offending specification, leaving the offending versatility thesis unattained. The lack of such studies may undermine the capability of comprehensively understanding the social learning patterns of online offending. Using a sample of 3741 Chinese college students, this study estimated an array of binary logistic regressions to compare the effects of traditional and online social learning in four types of online offending (online sexual harassment, cyberbullying, hacking, and digital piracy). The results suggest that offending versatility and offending specification co-exist in the social learning process of cyber deviance, while offending specification explains a marginally greater variance. Besides, online learning variables act as potential mediators in the relationships between traditional learning and cyber deviance. Furthermore, traditional social learning shows greater predictive power in cyber-enabled crimes than in cyber-dependent crimes. Our study provides fresh empirical evidence for the non-exclusive association between offending versatility and offending specification in the social learning process of cyber deviance.
Experimental and numerical investigation of shelf flow crossing over a strait
(Ocean Dynamics, 2024-05-20) Kuehl, Joseph; Sheremet, Vitalii A.
Motivated by the phenomenon of Scotian Shelf Crossover events, the problem of a shelf flow that is interrupted by a strait is considered. Laboratory experiments in a rotating tank with barotropic and baroclinic flow over flat and sloping shelves confirm that the flow is steered by the bathymetric contours and mainly circumnavigates the gulf. In order to jump across the strait, as suggested by earlier theories, the flow must have unrealistically high Rossby numbers. However, the near bottom friction relaxes the bathymetric constraint and causes the formation of a peculiar jet crossing the strait diagonally. For the dissipation values such that a half of the transport goes around the gulf and half crosses the strait diagonally, the diagonal crossover jet becomes most evident. Numerical solutions for realistic values of the frictional parameter reproduce the results of the laboratory experiments and consideration of the actual Gulf of Maine bathymetry reproduces patterns similar to those observed by drift trajectories and in the satellite derived sea surface temperature fields.
Records of fleas (Siphonaptera) from Delaware
(Journal of Medical Entomology, 2024-05-17) Kennedy, Ashley C.; Winter, Wil S.; Gardner, Alfred L.; Woodman, Neal; Shifflett, Scarlet A.; Redus, Sierra; Newcomer, Jeffrey R.; Eckerlin, Ralph P.
We present an annotated checklist of fleas (Siphonaptera) known to occur in the state of Delaware based on an examination of Siphonaptera collections at the University of Delaware and the Carnegie Museum of Natural History, as well as new specimens of fleas we collected from wildlife, other hosts, and tick flags. We review published records and compile them herein with our new records, which include 3 species previously unreported from Delaware. With these additions, there are now 18 flea species from 19 avian and mammalian hosts documented from Delaware.
Ultrawideband Modular RF Frontend Development for Photonically Enabled Imaging Receiver
(IEEE Microwave and Wireless Technology Letters, 2024-05-07) Shi, Shouyuan; Wang, Fuquan; Abney, Jeremy; Aranda, Zion D.; Schneider, Garrett J.; Schuetz, Christopher; Harrity, Charles; Shreve, Kevin; Zablocki, Mathew; Dontamsetti, Samhit; Lawrence, Robert; Prather, Dennis W.
This letter presents a modular-based RF frontend developed for photonically enabled phased-array systems that are capable of ultrawideband (UWB) operation from microwave to millimeter-wave (mmW) frequencies. The 1×8 modular architecture with integrated antennas, low-noise amplifiers (LNAs), and electrooptic modulators is reconfigurable and scalable to form 2-D phased arrays of any size. The developed phased-array system demonstrates the ability to process multiple wide-bandwidth RF beams simultaneously, yielding unmatched beam-bandwidth product (BBP).