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A generalist vector-transmitted parasite exhibits population genetic structure among host genera
No full textThis article was originally published in Parasitology. The version of record is available at: https://doi.org/10.1017/S0031182024001641.
© The Author(s), 2025. Published by Cambridge University Press.
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.Generalist parasites experience selective pressures from the various host species they infect. However, it is unclear if parasite transmission among host species precludes the establishment of host-specific adaptations and population genetic structure. We assessed the population genetic structure of the vector-transmitted avian haemosporidian parasite Haemoproteus majoris (lineage WW2; n = 34 infections) in a single site in southern Sweden among 10 of its host species. The 2 best-sampled host genera were Phylloscopus (2 species, n = 15 infections) and Sylvia (4 species, n = 15). We designed a sequence capture protocol to isolate 1.13 Mbp (ca. 5%) of the parasite genome and identified 1399 variable sites among the sequenced infections. In a principal components analysis, infections of Phylloscopus and Sylvia species mostly separated along the first 2 principal components. Sites with the highest FST values between the genera were found in genes that have mostly not been implicated in infection pathways, but several sites code for amino acid changes. An analysis of molecular variance confirmed significant variation among host genera, but not among host species within genera. The distribution of Tajima’s D among sequenced loci was negatively skewed, plausibly reflecting a history of bottleneck followed by population expansion. Tajima’s D was lower in infections of Phylloscopus than Sylvia, plausibly because WW2 began infecting Phylloscopus hosts after it was already a parasite of Sylvia hosts. Our results provide evidence of vector-transmitted parasite population differentiation among host species in a single location. Future work should focus on identifying the mechanisms underlying this genetic population structure.We performed bioinformatic and statistical analyses on the University of Delaware’s BIOMIX cluster, which is supported by Delaware INBRE (NIH/NIGMS P20 GM103446), NIH Shared Instrumentation Grant (S10OD028725), the State of Delaware, and the Delaware Biotechnology Institute. VAE was supported by funding from USDA Hatch (DEL00774, DEL00854, and NE1943) and from the Carl Tryggers Foundation (CTS16:53). The study was also supported by the Swedish Research Council through grants to OH (VR 2016–03419 and 2021-03663) and to SB (VR 2017-03937)
Limiting behaviors in molecular beam epitaxy: from source cell non-idealities to growth condition sensitivity of dilute bismuthides
No full textZide, Joshua M. O.The advancement of semiconductor technology increasingly depends on materials with precisely controlled properties and compositions. Among these, dilute bismuthides represent a promising yet challenging class of materials, where small amounts of bismuth dramatically modify the electronic structure of traditional III-V semiconductors. However, their development is hindered by stringent growth requirements and persistent reproducibility challenges. These challenges extend beyond typical material-specific considerations into instrumental limitations. ☐ This dissertation examines two fundamental limitations in molecular beam epitaxy (MBE) growth control through systematic investigation of source cell behavior and bismuthide growth optimization. First, we present a comprehensive study of commonly overlooked non-idealities in source cell operation - including hysteretic and non-hysteretic, history-dependent flux variation, spontaneous flux shifts, and others - that fundamentally limit growth reproducibility. These effects, while present in all MBE growth, become critical contributions when growing sensitive materials – including InAlBiAs, a non-natively lattice matched, quaternary dilute bismuthide. We develop novel calibration methods and operational guidelines to mitigate these limitations. ☐ Second, we study the growth window of InAlBiAs, mapping the complex interdependence of growth conditions, bismuth incorporation, and surface morphology.This investigation reveals a narrow growth window bounded by competing kinetic processes, which enables the study of native electrical properties of high-quality films. By developing a better understanding of induced strain, we achieve lattice-matched InAlBiAs films–a critical step toward practical device applications. ☐ Together, these studies provide new insights into the fundamental challenges limiting MBE growth control while establishing practical guidelines for growing emerging materials with stringent requirements. The findings have broad implications for the development of next-generation semiconductor devices and highlight the need to consider both equipment-level and material-specific limitations when growing novel materials. ☐ To fully explore these challenges in modern epitaxial growth, this dissertation begins with Chapter 1’s examination of relevant background on deposition techniques and semiconductor materials. Emphasis is placed on MBE and dilute bismuthides through in-depth discussion on growth thermodynamics and kinetics as relevant to dilute bismuthides. ☐ Chapter 2 describes the theory of various in situ and ex situ characterization techniques and their practical implementation throughout the remaining chapters. ☐ Chapter 3 studies the reproducibility and limitations of source cell behavior across liquid source cells, valved source cells, and filament source cells. It demonstrates several key physical phenomena related to source fluxes that could limit reproducibility and hinder interpretation of experimental results from certain sensitive materials (like dilute bismuthides). It additionally presents improved control strategies to mitigate the impact of the established effect. ☐ Chapter 4 studies the growth window of InAlBiAs and the inherent sensitivity of bismuth incorporation and surface morphology to non-ideal growth conditions. Additionally, it further explores InAlBiAs grown within the optimized growth window through characterization of native electrical properties and strain states of the films. As a proof-of-concept, it demonstrates how this new understanding of InAlBiAs can be used to grow lattice-matched material, enabling the future development of thick device structures without risk of dislocation nucleation.University of Delaware, Department of Materials Science and EngineeringPh.D
Mayor Pete is Smart and Elizabeth Warren is Unlikable? Coverage of Warmth and Competence Traits in the 2020 Democratic Presidential Primary
No full textThis article was originally published in Politics & Gender. The version of record is available at: https://doi.org/10.1017/S1743923X25000091.
© The Author(s), 2025. Published by Cambridge University Press on behalf of the Women, Gender, and Politics Research Section of the American Political Science Association.
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.Past work on media coverage of candidates for political office has explored gender differences in quantity, substance, and tone with mixed results depending on the office, race, and context. We draw on the stereotype content model (SCM) to examine gendered patterns of media coverage of candidates on the trait dimensions of warmth and competence in the 2020 U.S. Democratic presidential primary. Combining Natural Language Processing and manual analysis of news, we find that female candidates receive more negative than positive warmth coverage, while male candidates receive more tonally balanced warmth coverage, which suggests that female leaders are penalized on the dimension of warmth. Additionally, white women received more warmth coverage than women of color and women of color receive more competence coverage than white women. The findings suggest news media may portray white women and women of color candidates as lacking gender congruent traits like warmth but may portray white women as possessing role congruent traits like competence
RELATIONSHIP BETWEEN IRON MINERALS AND CARBON IN MARSH-FORESTED TRANSITIONS
No full textenterMarsh-forested transitions, or interfaces between upland forest systems and
tidal creeks, are dynamic coastal systems that play an important role in carbon
sequestration and mineral cycling. As the Delmarva Peninsula experiences increased
rates of relative sea level rise, it is increasingly urgent to understand biogeochemical
cycling within these critical areas. In this study, we investigated variability and
relationships of crystalline iron (Fe) oxides, short-range order Fe oxides, and water extractable organic carbon (WEOC) along three marsh-forested transitions located in
Delaware, Maryland, and Virginia. To assess Fe mineral concentrations in soils, we
used acid ammonium oxalate extractions for short-range order Fe oxides and citrate dithionite-bicarbonate to extract crystalline Fe oxides. For carbon in soils, we used
water extractions to determine WEOC concentrations and CHNS combustion analysis
to quantify total carbon. We observed variability in Fe oxide and WEOC
concentrations at site, subsite, and depth. In contrast with previous literature indicating
positive relationships between short-range order Fe oxides and carbon concentrations,
our results showed no statistically significant relationships. We did, however, see
significant negative relationships between crystalline Fe oxides and carbon at upland
forest subsites. The lack of correlation between short-range order Fe oxides and
carbon concentrations may be influenced by the dynamic redox conditions of marsh forested systems, which can prevent formation of Fe-organic complexes. Negative
relationships between crystalline Fe oxides and carbon indicate limited carbon
sequestration abilities of upland forests. These findings highlight the complex nature
of biogeochemical cycling along marsh-forested transitions and demonstrate the
influence that site-specific factors like redox conditions, salinity, and microbial
communities could have on these cycles. Our research had limited scale due to
sampling regime. Future research should emphasize additional sampling at the spatial
and temporal scale to fully understand Fe-carbon interactions and carbon cycling in
these critical systems.ente
Are Substance Use Deflection Programs Seen as Effective? Exploring Police Attitudes on Program Implementation
No full textThis article was originally published in Delaware Journal of Public Health. The version of record is available at: https://doi.org/10.32481/djph.2025.09.14
https://issuu.com/dam-dpha/docs/djph_11-3_substance_use_abuse_treatment_and_rec
Copyright (c) 2025 Delaware Academy of Medicine / Delaware Public Health Association. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc-nd/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.Objective: To determine the prevalence and determinants of beliefs in substance use deflection programs’ effectiveness among police officers working in agencies with diversion initiatives. Methods: We present responses from an anonymous online survey about deflection programs fielded to all law enforcement officers in the State of Delaware in January 2025. A total of 111 officers reported working in an agency with a substance use deflection program and completed relevant survey questions. Descriptive statistics summarize police officers' views on program effectiveness, attitudes toward leadership, beliefs in enforcing the law, occupational experiences, and personal characteristics. Logistic regression models isolate the factors associated with beliefs in program effectiveness. Descriptive statistics identify common barriers to deflection program implementation. Results: A majority (59%) believe their programs are effective. On average, over three-quarters of respondents express that deflection programs are appropriate, feasible, and implementable. Tough-on-crime attitudes and being in a position for less than five years diminish the likelihood of stating that a deflection program is effective. Knowing someone who has a substance use or mental health disorder and working in a larger police department increases perceptions of program effectiveness. The three most commonly cited barriers to program implementation were having people interested in treatment, homelessness/housing issues, and the potential ineffectiveness of diversion. Conclusions: Police officers generally believe their departments’ substance use deflection programs are successful. Even more officers think programs can be easily and appropriately implemented. Commonly cited barriers highlight the difficulties in addressing substance use in communities. Policy Implications: This overall support for deflection underscores the potential for further cross-system collaborations with public health practitioners. Such partnerships may also be vital in addressing barriers that inhibit law enforcement-based deflection efforts. Further evaluation and research efforts can demonstrate the impacts of substance use deflection and the practices that make deflection programs more successful.This work was supported by the Comprehensive Opioid Abuse Site-based Program (COSSAP) (15PBJA-22-GG-04461-COAP) through the State Criminal Justice Council. Views expressed in this article are those of the authors
Impacts of water and residue management on soil health indicators in rice paddy soil
No full textSeyfferth, Angelia L.Soil health is the foundation for successful agriculture, and indicative tests have been developed to assess soil health for soils that support many upland crops. Healthy soil is typically characterized by key biological, chemical, and physical traits, including an active microbial community, high organic carbon, and stable aggregation. Rice, a globally essential food crop, presents unique soil health challenges due to its cultivation in flooded conditions, and it is unclear if traditional soil health frameworks apply to rice cultivation. Key concerns in rice agroecosystems include elevated grain As levels, excessive irrigation water use, and CH4 emissions, which threaten human health, environmental sustainability, and contribute to climate change. This study explores how water and residue management strategies, factors that heavily influence As and C cycling, affect soil health test results. We found that, of the 26 soil health indicators tested, 15 were sensitive to water management and 20 were sensitive to residue management, even though water had a stronger impact on grain As concentration and CH4 emissions than crop residues. Comprehensive Assessment of Soil Health (CASH) scoring, modified to include grain As and CH4 emissions, indicated that non-flooded and straw-amended paddies produced the healthiest soil. Of the 26 soil health tests used, 16 had significant correlations with yield, 11 with grain As, and 18 with CH4 emissions. Mehlich-3 extractable Fe was highly affected by water and residue management, and had the strongest correlations with yield, grain As, and CH4 emissions. By identifying soil health tests that are sensitive to these management practices and addressing As and CH4 concerns without compromising yield, this research aims to provide rice farmers and researchers with practical tools to enhance soil health while balancing environmental and human health considerations.University of Delaware, Department of Plant and Soil SciencesM.S
Low-Q Asymptotic Behavior of the Effective Structure Factor Yields Model-Independent Radius of Interparticle Interaction (Ri)
No full textThis article was originally published in [Journal Name]. The version of record is available at: https://doi.org/10.1021/acsmeasuresciau.5c00099
This article is licensed under CC-BY 4.0 https://creativecommons.org/licenses/by/4.0/Guinier analysis has been extensively used in academic and industrial research settings to obtain the model-independent size of a polymer, protein, or colloid in solution from small-angle scattering data. Using the Guinier model, the radius of gyration (Rg) is extracted from the form factor at low Q. Here, we develop an analogous approach for analyzing the effective structure factor data at low Q to extract a model-independent radius of interaction potential, Ri. Whereas Rg describes how spread out the scattering length density distribution of particles is from their center of mass, Ri is an effective root-mean-square distance that quantifies how far the interparticle correlation deviates from its ideal gas configuration due to interactions. We demonstrate this novel analysis method by applying it to experimental small-angle neutron scattering data on lysozyme protein solutions. We discuss its broad implications for analysis of low-Q asymptotic X-ray and neutron scattering data, where Guinier analysis is traditionally applied.This project was supported by C.E.R. Edwards’s appointment to the National Research Council (NRC) Research Associateship Program (RAP) at the National Institute of Standards and Technology (NIST), administered by the Fellowships Office of the National Academies of Sciences, Engineering, and Medicine (NASEM). Y. Liu acknowledges the support by the Center for High Resolution Neutron Scattering, a partnership between the National Institute of Standards and Technology and the National Science Foundation under Agreement No. DMR-2010792. The authors thank Drs. John Barker, Ryan Murphy, and Susana Teixeira at the NIST Center for Neutron Research for helpful discussions about SANS data quality, background subtraction, and the current limits of accurate low-concentration measurements and Dr. Alexandros Chremos of the NIST Chemical Informatics Group for helpful feedback on the manuscript. Certain commercial equipment, instruments, or materials (or suppliers, or software, etc.) are identified in this paper to foster understanding. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the materials or equipment identified are necessarily the best available for the purpose. This research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. SANS studies were performed using the Bio-SANS instrument of the Center for Structural Molecular Biology (FWP ERKP291), a DOE Office of Biological and Environmental Research (OBER) Structural Biology Resource. The beam time was allocated to proposal number IPTS-33061
Vanadium dioxide deposited by pulsed laser deposition: from materials optimization to applications in terahertz modulation
No full textWang, XiThis dissertation discusses the synthesis, characterization, and application of phase transition materials, particularly vanadium dioxide (VO2), in dynamically tunable terahertz (THz) modulators. By leveraging pulsed laser deposition (PLD), this work demonstrates the fabrication of VO2 thin films with high quality, large-scale uniformity, and exceptional consistency, providing a foundation for THz modulation using phase transition materials. ☐ The dissertation begins by reviewing conventional THz modulation approaches, highlighting the advantages of utilizing phase transition materials and THz waves. Different methods of THz modulation and their advantages are discussed. The physical and electronic properties of VO2, including its insulator-to-metal transition, are explored, along with a comparison with other synthesis methods of phase change materials. ☐ A key part of this work is the optimized deposition of polycrystalline VO2 thin films using PLD. A comprehensive study on the VO2 deposition recipes and the quality of VO2 thin films are discussed. Characterization, including ellipsometry, resistance-temperature measurements, and terahertz time-domain spectroscopy (THz-TDS), confirms the high quality and reproducibility of the deposited VO2 thin films. ☐ The dissertation further presents the design, fabrication, and experimental results of a VO2-based THz beam steering metasurface. It achieves nearly 100% ordinary transmission in the "OFF" state and demonstrates broadband THz beam control. ☐ Furthermore, it introduces MEMS-actuated THz metamaterials, where the mechanical deformation of VO2 thin films serves as the actuator of a THz polarization modulator. The results reveal strong THz polarization modulation capabilities and enhanced tunability, which could be used in reconfigurable THz devices. ☐ In summary, the dissertation focuses on phase transition materials VO2 and THz modulation, providing new design concepts and operational mechanisms that can be further utilized in various devices and platforms. With optimized performance and capabilities, advanced optical applications, such as improved THz telecommunications, imaging, and sensing, could be realized.University of Delaware, Department of Materials Science and EngineeringPh.D