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Investigating the molecular and neural mechanisms mediating social stress
No full textShao, LishaMaintaining an optimal social density is essential for the physical and mental health of humans and many other organisms. Stress caused by extreme social densities (ESD), including social isolation and crowding, can lead to different mental and physical health issues such as anxiety, depression, addiction and neurodegenerative diseases. However, the underlying molecular and neural mechanisms mediating the ESD-induced stress is poorly understood. In addition, it is also unclear about how the body senses and adapts to the long-term effects of ESD, including the associated behavioral and physiological changes. Drosophila melanogaster has been shown to be a versatile tool to study the neural circuits mediating social dynamics among individuals of the same species. Previous studies have shown that social isolation alters the behaviors in male flies, and our preliminary study on female flies also demonstrated that chronic ESD has altered behaviors including mating, feeding, and social spacing, as well as the level of major metabolites. To further understand the molecular mechanisms underlying how ESD affects female Drosophila, we have identified multiple differentially expressed genes (DEGs) associated with ESD using RNA-Sequencing. The DEGs are involved in pathways essential for cellular metabolism, oxidative stress, olfactory sensory pathways and neuronal protection. Based on our preliminary findings, we hypothesize that ESD systematically alters the physiology and behavior of Drosophila through a complex of molecular and sensory mechanisms. My study sheds light on how social density is perceived and processed by the brain and in turn regulates individual’s behavior and physiology and therefore provide insights into potential therapeutic targets of social stress related illnesses.University of Delaware, Department of Biological SciencesM.S
Geologic Map of the Newark West, Newark East, and Wilmington South Quadrangles, Delaware
No full textGeologic mapping was conducted at 1:12,000 with a 1-ft topographic contour basemap. In some instances, stratigraphic boundaries drawn at topographic breaks and highs reflect detailed mapping using LiDAR data. Elevations of stratigraphic contacts along stream valleys are projected from subsurface data. Except for a few erosional bluffs, these contacts are covered by colluvium. This map supersedes this portion of Geologic Map of New Castle County, Delaware: Delaware Geological Survey Geologic Map Series No. 13 (Ramsey, 2005a), Geology of the Newark area, Delaware: Delaware Geological Survey Geologic Map Series No. 3 (Woodruff and Thompson, 1972), and Geology of the Wilmington area, Delaware: Delaware Geological Survey Geologic Map Series No. 4 (Woodruff and Thompson, 1975). Piedmont bedrock units are not included on this map and a generalized cutoff is drawn beyond which Coastal Plain units have not been recognized. Where shown on the map, the Piedmont is saprolite, the weathered zone that overlies the unweathered bedrock. Schenck (2021) and Schenck and others (2000) document the Piedmont stratigraphic units in detail
Advancing magnonics: from magnonic interferometry to dynamic hybrid systems
No full textJungfleisch, BenjaminSpin waves are collective excitations of the electron spin system in magnetically ordered materials. Their quasiparticles – magnons – are considered promising candidates for wave-based information processing due to their robustness against local perturbations, low energy dissipation, and compatibility with Complementary Metal-Oxide-Semiconductor technology and device miniaturization. Controlled propagation and interference of spin waves enable the development of a wide range of magnonic devices, such as spin-wave logic gates, interferometers, directional couplers, demultiplexers, and transistors. This thesis addresses key challenges in magnonics, including the control of spin-wave propagation in extended thin films and the optimization of coherent coupling between spin waves and microwave photons. ☐ In the first part, we investigate the emission of a directional, focused spin-wave beam – referred to as a caustic spin-wave – from a nano-constricted microwave waveguide and its subsequent propagation into an unpatterned, extended thin yttrium iron garnet film. We observe non-reciprocal propagation of the beam that depends on the orientation of the external magnetic field. This non-reciprocity arises from the chiral coupling between spin waves and the microwave magnetic field localized near the constriction. The direction of beam propagation can be tuned by adjusting either the external field or the microwave frequency. ☐ The second part of this thesis explores hybrid magnonics – a quantum framework for transducing energy and information between spin systems and other platforms, including microwave photons and magnons. We report coherent coupling between incoherent (thermal) magnons in a magnetic insulator–conductor hybrid system. Specifically, thermally excited uniform modes and higher-wavevector Damon–Eshbach modes in Ni80Fe20 couple to perpendicular standing spin waves in yttrium iron garnet, facilitated by strong interfacial exchange coupling. These observations are in good agreement with spin pumping and spin rectification measurements. ☐ We further examine magnon–photon hybridization in both bulk and thin-film magnetic samples using three-dimensional microwave cavities and planar resonators. By employing larger samples, strategically placing them at positions of maximum microwave magnetic field within the resonator, and engineering the resonator geometry, we optimize the coupling strength. Under strong microwave drive, the system transitions to a nonlinear regime when Suhl’s first instability condition is satisfied, leading to linewidth broadening and a reduction in coupling strength. Notably, we demonstratefor the first time-a controlled electrical readout of the magnon–photon coupling via the inverse spin Hall effect in a superconducting circuit at cryogenic temperatures. This result marks a significant step toward electrically detecting coherent light–matter interactions at the quantum level. ☐ These findings advance condensed matter physics and magnonics in particular, by addressing key challenges in wave-based information processing. The demonstrated control of spin-wave propagation and the optimized magnon–photon coupling pave the way for compact, low-power magnonic hybrid quantum devices – such as spin-wave logic gates, sensors, tunable microwave components, and scalable quantum transducers.University of Delaware, Department of Physics and AstronomyPh.D
Revealing the Accelerating Wind in the Inner Region of Colliding-wind Binary WR 112
No full textThis article was originally published in The Astronomical Journal The version of record is available at:https://doi.org/10.3847/1538-3881/adfa03
©2025.TheAuthor(s).Published by the American Astronomical Society.
Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. (https://creativecommons.org/licenses/by/4.0/) Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.Colliding winds in massive binaries generate X-ray-bright shocks, synchrotron radio emission, and sometimes even dusty “pinwheel” spirals. We report the first X-ray detections of the dusty WC+O binary system WR 112 from Chandra and Swift, alongside 27 yr of Very Large Array/Australia Telescope Compact Array radio monitoring and new diffraction-limited Keck images. Because we view the nearly circular orbit almost edge-on, the colliding-wind zone alternates between heavy Wolf–Rayet wind self-absorption and near-transparent O-star wind foreground each 20 yr orbit, producing phase-locked radio and X-ray variability. This scenario leads to a prediction that the radio spectral index is flatter from a larger nonthermal contribution around the radio intensity maximum, which indeed was observed. Existing models that assume a single dust-expansion speed fail to reproduce the combined infrared (IR) geometry and radio light curve. Instead, we require an accelerating postshock flow that climbs from near-stationary to ∼1350 km s−1 in about one orbital cycle, naturally matching the IR spiral from 5″ down to within 0".1, while also fitting the phase of the radio brightening. These kinematic constraints supply critical boundary conditions for future hydrodynamic simulations, which can link hot-plasma cooling, nonthermal radio emission, X-ray spectra, and dust formation in a self-consistent framework. WR 112 thus joins WR 140, WR 104, and WR 70-16 (Apep) as a benchmark system for testing colliding-wind physics under an increasingly diverse range of orbital architectures and physical conditions.Support for this work was provided by the National Aeronautics and Space Administration through Chandra Award Number 23200246 issued by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of the National Aeronautics Space Administration under contract NAS8-03060.
The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.
The Australia Telescope Compact Array is part of the Australia Telescope National Facility (grid.421683.a), which is funded by the Australian Government for operation as a National Facility managed by CSIRO. We acknowledge the Gomeroi people as the traditional owners of the Observatory site.
Some of the data presented herein were obtained at Keck Observatory, which is a private 501(c)3 nonprofit organization operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the Native Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
M.F.C. and K.H. are supported by NASA under grant Nos. 80GSFC21M0002 and 80GSFC24M0006. J.J.W. acknowledges support by the Heising-Simons Foundation (grant No. 2023-4598) and the Alfred P. Sloan Foundation. S.B. acknowledges funding from the Dutch research council (NWO) under the talent program (Vidi grant VI.Vidi.203.093). J.D.M. and M.C. acknowledge support from Chandra Award No. GO2-23012B. J.R.C. acknowledges funding from the European Union via the European Research Council (ERC) grant Epaphus (project number 101166008). C.M.P.R. acknowledges support from NASA Chandra Theory grant No. TM3-24001X
In-depth stability characterization and engineering of bacterial N-terminal motifs and their protective tags
No full textKunjapur, Aditya M.,Protein degradation plays a pivotal role in the maintenance of the cell by recycling abnormally expressed proteins and regulating stimuli-responsive protein lifespans. A protein degradation pathway of particular interest is the N-degron pathway, where short N-terminal motifs known as N-degrons can modulate protein half-life from two minutes to over ten hours. Initially, substrate specificity in this pathway was thought to depend solely on the identity of the first amino acid; however, recent studies have revealed that residues up to the fifth position from the N-terminus can significantly influence protein stability. Consequently, there remain open questions about how precisely the amino acid sequence of N-terminal regions governs protein stability as well as how generalizable are previously observed sequence trends. Clarifying substrate preferences within this pathway would enable biological engineers to finely control protein half-life and prevent unwanted degradation of recombinant proteins. ☐ To monitor protein degradation in vivo, we adapted the ubiquitin fusion technique to create a dual fluorescent reporter, allowing us to differentiate destabilizing degrons and stable sequences over three orders of signal magnitude. Utilizing this assay, we screened novel pathway candidates including highly destabilizing sequences derived from human and plant N-degrons. Using these imported sequences as templates, we established a high-throughput screening platform combining DNA library generation, fluorescence-activated cell sorting (FACS), and next-generation sequencing (NGS), allowing simultaneous analysis of numerous sequences. After validating our platform with a 60-member library screen, we scaled the platform to analyze combinatorially mutagenized sequences across the first five N-terminal amino acids, generating detailed sequence-specificity maps from over 800,000 sequences at a depth of at least 20 reads per sequence. ☐ This extensive dataset revealed previously undiscovered trends in the bulk data, such as the destabilizing impact of glutamine and the stabilizing effects of glycine and proline residues downstream of the N-terminal position. It has also revealed trends that are specific to certain sequence contexts, such as how two bulky residues at positions two and three can occasionally convert a sequence with a canonically stable N-terminal residue, such as Nt-Cys, into an N-degron. Furthermore, we have characterized sequence stability trends for synthetic N-termini commonly used for small molecule or protein ligation, such as Nt-Cys, Gly, and Ser. Leveraging these insights, we developed N-FIVE, a machine learning model capable of predicting and recommending N-terminal sequences based on desired stability profiles. Collectively, these findings represent the most comprehensive characterization of the Escherichia coli N-degron pathway to date and provide practical insights for protein lifespan modulation. ☐ Despite its potential, the N-degron pathway remains underutilized in a biological engineering context, partly due to limited methods for dynamically exposing neo-N-termini. Addressing this challenge could unlock valuable applications, including dynamic protein lifespan switches. To resolve fundamental obstacles in neo-N-termini generation, we first evaluated the stability of widely-used protective tags. Notably, we observed unexpected cleavage of ubiquitin and SUMO fusions in common E. coli strains. By identifying and knocking out four candidate deubiquitinases in BL21, we engineered the Zero observable Ubiquitin cleavage (sUbZero) strain, significantly enhancing ubiquitin-fusion stability and improving yields by over 50%. Next, we developed a SUMO protease (Ulp1) that is dependent on the nonstandard amino acid o-methyltyrosine for expression. Using this engineered protease, we created an inducible protein stability switch. We demonstrated its ability to conditionally remove protective tags, enabling degradation of N-degron-tagged proteins. Subsequently, we have utilized this technology to regulate the lifespan of a toxin, showing a proof of concept that the toxin’s function can be negated in the presence of our engineered protease. Future directions and optimization strategies for conditional cell death in a biocontainment application are also discussed. ☐ In summary, this thesis advances our understanding and application of how N-terminal protein motifs govern protein stability. By screening and analyzing millions of N-degron candidates and overcoming key barriers related to engineered protective tag removal, we provide new insights and practical tools that empower biological engineers to precisely tune protein half-life.University of Delaware, Department of Chemical and Biomolecular EngineeringPh.D
"Land to the tiller! Education for all!": constellating the Ethiopian Student Movement and the Black Radical Tradition
No full textMaloba, Wunyabari O.The 1960s Ethiopian Student Movement (ESM), a moment where the youth’s radical fervor and commitment to a socialist Ethiopia was a harbinger of the end of empire, is a significant moment in the trajectory of Ethiopian political history worth intervening and reconstituting as part of the Black Radical Tradition (BRT). Ethiopia’s presumed history of remaining uncolonized in the face of European domination has created a “picturesque medievalism of kings and queens” while masking the “overwhelming reality of the misery” of the Ethiopian people.1 And despite the sustenance of this misleading image, scholars have attempted to establish Ethiopia’s albeit differing coloniality and the emergent decolonial politic embraced by Ethiopian students and activists in the mid-century against Haile Selassie II’s feudalist and imperialist empire. This study aims to intervene here and contribute to the scholarship regarding the ESM to show how the Ethiopian students’ ideological posture on the socioeconomic and national questions of Ethiopia was a manifestation of the phenomenon that is the BRT. Resituating the ESM within this inherited tradition establishes Ethiopia’s radical past, more accurately, as part of the transnational Black revolt uninterested in reformation, but rather socialist world-building—a moment in Ethiopian history overlooked, simplified and relentlessly critiqued. 1 Ethiopian Students Union in North America, “Repression in Ethiopia,” Africa Research Group 5, (1971): 1.University of Delaware, Department of Africana StudiesM.A
Why do countries adopt (or abandon) gender-responsive budget policies?: the case of Australia, 2014-2022
No full textJustice, Jonathan B.The term gender-responsive budgeting (GRB) encompasses a range of analytic approaches and other policy tools intended to steer public budget processes and allocations toward greater equality for men and women. By the second decade of this century, at least 80 – roughly a third – of the world's countries had adopted some version of GRB. GRB-adopting countries span the range of the world's regions and income levels, with no obvious pattern connecting region, culture, or economic conditions to the adoption or non-adoption of GRB initiatives. Why do some countries adopt GRB while others do not? As a first step toward answering that question, we used the advocacy coalition framework to structure a process-tracing examination of three recent GRB policy changes in Australia. Australia in 1983 became the first county in the world to adopt GRB and began producing an annual Women's Budget Statement (WBS) in 1984. That practice was abandoned in 2014 following a change of government but later re-adopted in 2021 by the same government in the wake of a political scandal. A new government took office in 2022 and substituted its own WBS for the previous government's several months into the 2022-2023 fiscal year. The processes leading to those policy changes were consistent with the ACF's general hypotheses about the causes of policy change but can also be explained as the results of electoral politics and partisan electoral maneuvering.University of Delaware, School of Public Policy and AdministrationM.P.P
A WAVE OF CHANGE FOR SUSTAINABLE ECO-TOURISM
No full textMISSION
This project is dedicated to the ecological restoration and cultural revitalization of Devil’s Bridge, a protected park in Antigua that has suffered the environmental impacts of unmanaged tourism, and unsustainable farming practices. My mission is to transform this fragile landscape into a resilient green sanctuary that not only supports the regeneration of native and endemic species, but also honor the land’s historical and cultural narratives. By incorporating sustainable eco-tourism, a model that balances conservation with access will welcome visitors in a way that educates, inspires, and preserves. Educational signage, interpretive trails, and community led initiatives will offer immersive experiences that highlight the area’s unique geology, biodiversity, and cultural heritage. This project envisions a future where Devil’s Bridge is no longer viewed simply as a tourist destination, but as a living classroom, a sacred space, and a symbol of ecological resilience. Through collaboration with local stakeholders, conservationists, and educators, I seek to ensure that future generations experiences a Devil’s Bridge that is not only beautiful, but thriving, protected, and deeply respected.
GOALS
The goals of the Devil’s Bridge Restoration Project are to rehabilitate native habitats, support biodiversity, and protect the site's natural and cultural heritage. By integrating sustainable ecotourism infrastructure, I aim to reduce environmental impact while enriching the visitor experience. The project also seeks to honor the area's Afro-Caribbean history through culturally sensitive storytelling and interpretation. Through community engagement and environmental education, we hope to inspire stewardship and deepen public understanding. Ultimately, our goal is to build climate resilience and ensure long-term protection of this sacred and ecologically significant landscape.
OBJECTIVES
The objectives of this project are to restore native plant communities and improve habitat conditions for endemic species at Devil’s Bridge, while designing low-impact pathways and viewing areas to manage foot traffic and prevent further degradation. I aim to create a design that communicates the site’s ecological and cultural significance, and to actively involve local communities in stewardship and interpretation efforts. These objectives will guide future efforts to ensure the site’s preservation, accessibility, and relevance for future generationsWik, Ann