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Outer Solar System spacecraft without drag-free control to probe the μHz gravitational wave frontier
No full textThe microhertz frequency band of gravitational waves probes the merger of supermassive black holes as well as many other gravitational wave phenomena. However, space-interferometry methods that use test masses would require substantial development of test-mass isolation systems to detect anticipated astrophysical events. We propose an approach that avoids inertial test masses by situating spacecraft in the low-acceleration environment of the outer Solar System. We show that for Earth-spacecraft and inter-spacecraft distances of ≳10 AU, the accelerations on the spacecraft would be sufficiently small to potentially achieve sensitivities determined by stochastic gravitational wave backgrounds. We further argue, for arm lengths of 10−30 AU and ∼10 Watt transmissions, that stable phase locks should be achievable with 20 cm mirrors or 5 m radio dishes. We discuss designs that send both laser beams and radio waves between the spacecraft, finding that despite the ∼10 ⁴× longer wavelengths, even a design with radio transmissions could reach stochastic background-limited sensitivities at ≲0.3×10⁻⁴ Hz. Operating in the radio significantly reduces many spacecraft design tolerances. Our baseline concept requires two arms to do interferometry. However, if one spacecraft carries a clock with Allan deviations at 10 ⁴ seconds of 10⁻¹⁷, a comparable sensitivity could be achieved with a single arm. Finally, we discuss the feasibility of achieving similar gravitational wave sensitivities in a `Doppler tracking' configuration where the single arm is anchored to Earth.This work is supported by NASA/NIAC Phase I award 80NSSC24K0644. C.M. would like to acknowledge support by NASA under award number 80GSFC24M0006.https://iopscience.iop.org/article/10.3847/1538-4357/adf5a2/met
Radial Evolution of Interplanetary Shock Properties with Heliospheric Distance: Observations from Parker Solar Probe
No full textWe present a comprehensive analysis of 66 interplanetary shocks observed by the Parker Solar Probe between 2018 November and 2024 January. Among these, 33 events fulfilled the Rankine–Hugoniot (R-H) conditions, ensuring reliable asymptotic plasma parameter solutions. The remaining 33 events could not be confirmed by the standard R-H approach—potentially including wave-like structures—yet were analyzed via averaging and mixed-data methods to obtain robust shock parameters. Utilizing our ShOck Detection Algorithm database, the shocks are categorized into fast-forward, fast-reverse, slow-forward, and slow-reverse types. We investigate the statistical properties of these shocks, focusing on correlations between key parameters—magnetic field compression, density compression, shock normal angle, and change in velocity—and heliocentric distance. Significant positive correlations are identified between heliocentric distance and both magnetic field compression and density compression, suggesting that shocks strengthen as they propagate away from the Sun, largely due to the high local magnetosonic speeds closer to the Sun that can suppress shock formation except in extremely fast events. These findings provide new insights into the dynamic processes governing shock evolution in the inner heliosphere, including scenarios where the near-radial magnetic field geometry may lead to predominantly quasi-parallel shock configurations and thus affect near-Sun particle acceleration efficiency. We also provide strong evidence for the existence of slow-mode shocks near the Sun, contributing to the understanding of shock formation and evolution in the inner heliosphere.The Parker Solar Probe was designed, built, and is now operated by the Johns Hopkins Applied Physics Laboratory as part of NASA's Living with a Star (LWS) program (contract NNN06AA01C). The work of the Czech authors was supported by the Czech Science Foundation under Contracts 23-06401S and partially by the International Space Science Institute (ISSI) in Bern through International Team project No. 23-575 (J.S. and Z.N.). V.K. was supported by the STEREO/WAVES and Wind/WAVES projects and by the NASA grant 19-HSR19_2-0143.https://iopscience.iop.org/article/10.3847/2041-8213/ada55
Implantation of Islets Co-Seeded with Tregs in a Novel Biomaterial Reverses Diabetes in the NOD Mouse Model
No full textBACKGROUND: Type 1 diabetes (T1D) results in autoreactive T cells chronically destroying pancreatic islets. This often results in irreplaceable loss of insulin-producing beta cells. To reverse course, a combinatorial strategy of employing glucose-responsive insulin restoration coupled with inhibiting autoreactive immune responses is required. METHODS: Non-obese diabetic mice received a single intraperitoneal implantation of a novel biomaterial co-seeded with insulin-producing islets and T regulatory cells (Tregs). Controls included biomaterial seeded solely with islets, or biomaterial only groups. Mice were interrogated for changes in inflammation and diabetes progression via blood glucose monitoring, multiplex serum cytokine profiling, flow cytometry and immunohistochemistry assessments. RESULTS: Islet and Tregs co-seeded biomaterial recipients had increased longevity, insulin secretion, and normoglycemia through 180 days post-implantation compared to controls. Serum profile revealed reduced TNFα, IFNγ, IL-1β and increased IL-10, insulin, C-Peptide, PP and PPY in recipients receiving co-seeded biomaterial. Evaluation of the resected co-seeded biomaterial revealed reduced infiltrating autoreactive CD8 + and CD4 + T cells concomitant with sustained presence of Foxp3 + Tregs; further analysis revealed that the few infiltrated resident effector CD4⁺ or CD8⁺ T cells were anergic, as measured by low levels of IFNγ and Granzyme-B upon stimulation when compared to controls. Interestingly, studies also revealed increased Tregs in the pancreas. However, there was no restoration of the pancreas beta cell compartment, suggesting normoglycemia and production of insulin levels were largely supported by the implanted co-seeded biomaterial. CONCLUSION: These studies show the efficacy of a combinatorial approach seeding Tregs with pancreatic islets in a novel self-assembling organoid for reversing T1D.We acknowledge the U.S. National Institutes of Health (SC1GM127207, R35GM145290 and K99DK136921), Department of Defense (W911NF-14-1-0123) and National Science Foundation (grant #1428768) for financial support for this project.https://link.springer.com/article/10.1007/s13770-024-00685-
A comparison of the meridional meandering of extratropical precipitation during boreal winter: eddy momentum flux versus Eulerian storm tracks
No full textThe latitudinal distribution of winter extratropical precipitation is often regarded as being determined by the location and intensity of the storm track. Here, we compare the precipitation variability associated with the meridional eddy momentum flux (EMF) with that associated with an Eulerian storm track measure. Observations show that when the midlatitude EMF is anomalously poleward, the occurrence of moderate-to-heavy precipitation (1–33 mm day⁻¹) increases between 45°N and 70°N, while decreasing between 25°N and 45°N. This shift occurs mostly downstream of the climatological storm track maximum, with generally greater precipitation anomalies compared to those associated with storm track changes. The shift is tied to changes in horizontal moisture transport primarily by planetary scale waves. These results suggest that, in addition to the storm track intensity, dynamics of the horizontal wave tilts which affect the EMF intensity need to be considered when projecting future changes in precipitation variability.C.Y. and S.L. were supported by the National Research Foundation of Korea through grant RS-2023-00219006. C.Y. was also supported by the National Research Foundation of Korea through grant RS-2024-00333469 and by the Specialized University Program for Confluence Analysis of Weather and Climate Data of the Korea Meteorological Institute. S.L. also acknowledges support by U.S. National Science Foundation AGS-2343772.https://www.nature.com/articles/s41612-025-00992-
Echoes of Trauma: The Lingering Health Effects of Childhood Sexual Abuse Throughout the Life-course
No full textEchoes of Trauma: The Lingering Health Effects of Childhood Sexual Abuse Throughout the Life-course In this scoping review, my research partner Imani Conway and I sought to systematically explore the profound and long-lasting health impacts of childhood sexual abuse (CSA) on women. By synthesizing an extensive range of studies, we aimed to highlight the varied ways CSA affects health across the lifespan. Our findings indicate that CSA is linked to numerous chronic health conditions, including gastrointestinal and cardiovascular diseases, reproductive health issues, and psychiatric disorders. Additionally, CSA survivors face increased risks for chronic pain, maladaptive health behaviors, and socioeconomic challenges, such as diminished educational and economic outcomes. We hope this work underscores the urgent need for trauma-informed care in healthcare systems, prioritizing prevention, early intervention, and provider education to better meet the needs of CSA survivors. This research is a call to action for both healthcare providers and policymakers to address the pervasive effects of CSA on women's long-term health and quality of life.https://andreakalfoglou.com/research
The infrared counterpart and proper motion of magnetar SGR 0501+4516
No full textAims. Soft gamma repeaters (SGRs) are highly magnetised neutron stars (magnetars) notable for their gamma-ray and X-ray outbursts. We used near-infrared (NIR) imaging of SGR 0501+4516 in the days, weeks, and years after its 2008 outburst to characterise the multi-wavelength emission, and to obtain a proper motion from our long temporal baseline observations.
Methods. We present short- and long-term monitoring of the IR counterpart of SGR 0501+4516 and a measurement of its proper motion. Unlike most magnetars, the source has only moderate foreground extinction with minimal crowding. Our observations began only ∼2 hours after the first activation of SGR 0501+4516 in August 2008 and continued for ∼4 years, including two epochs of Hubble Space Telescope (HST) imaging. The proper motion constraint was improved using a third HST epoch from 10 years later.
Results. The NIR and X-rays faded slowly during the first week, which was followed by a steeper power-law decay. The behaviour is satisfactorily fit by a broken power law. Three epochs of HST imaging with a 10-year baseline allowed us to determine the quiescent level and to measure a proper motion of μ = 5.4 ± 0.6 mas yr−1. This corresponds to a low transverse peculiar velocity of v ≃ 51 ± 14 km s−1 (at 2 kpc). The magnitude and direction of the proper motion rules out supernova remnant HB9 as the birth site. We can find no other supernova remnants or groups of massive stars within the region traversed by SGR 0501+4516 during its characteristic lifetime (∼20 kyr).
Conclusions. Our observations of SGR 0501+4516 suggest three possibilities: that some magnetars are significantly older than expected, that their progenitors produce low supernova ejecta masses, or that they can be formed through accretion-induced collapse or low-mass neutron star mergers. Although the progenitor of SGR 0501+4516 remains unclear, we propose that SGR 0501+4516 is the best Galactic candidate for a magnetar formed through a mechanism other than massive star core-collapse.The authors thank Jos de Bruijne David Green and David O Neill for helpful discussions and the anonymous referee for their careful consideration of the manuscript AAC acknowledges support through the European Space Agency ESA research fellowship programme JDL acknowledges support from a UK Research and Innovation FellowshipMR T020784 1 VSD is supported by STFC NRT is supported by STFC Consolidated grant ST W000857 1 NR is supported by the European Research Council ERC via the Consolidator Grant MAGNESIA No 817661 and the Proof of Concept DeepSpacePulse No 101189496 by the Catalan grant SGR202101269 by the Spanish grant PID2023153099NAI00 and by the program Unidad de Excelencia Maria de Maeztu CEX2020001058M DS acknowledges support from the Science and Technology Facilities Council STFC grant numbers ST T007184 1 ST T003103 1 ST T000406 1 and ST Z000165 1 The material is based upon work supported by NASA under award number 80GSFC24M0006 Observations analysed in this work were taken by the NASA ESA Hubble Space Telescope under programs 12306 12672 and 16019 PI: Levan This work made use of data from the European Space Agency ESA mission Gaia https: www cosmos esa int Gaia processed by the Gaia Data Processing and Analysis Consortium DPAC https: www cosmos esa int web Gaia dpac consortium Funding for the DPAC has been provided by national institutions in particular the institutions participating in the Gaia Multilateral Agreement This paper makes use of data obtained as part of the IGAPS merger of the IPHAS and UVEX surveys www igapsimages org carried out at the Isaac Newton Telescope INT The INT is operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias All IGAPS data were processed by the Cambridge Astronomical Survey Unit at the Institute of Astronomy in Cambridge The uniformlycalibrated bandmerged IGAPS catalogue was assembled using the high performance computing cluster via the Centre for Astrophysics Research University of Hertfordshire The United Kingdom Infrared Telescope is operated by the Joint Astronomy Centre on behalf of the Science and Technology Facilities Council of the U K We thank Nancy Levison for awarding DDT observations with Gemini and the ING group for their assistance with our observations at the WHT The WHT is operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias Based on observations obtained at the Gemini Observatory which is operated by the Association of Universities for Research in Astronomy Inc under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation United States the Science and Technology Facilities Council United Kingdom the National Research Council Canada CONICYT Chile the Australian Research Council Australia Ministério da Cióncia e Tecnologia Brazil and SECYT Argentina This publication makes use of data products from the Two Micron All Sky Survey which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center California Institute of Technology funded by the National Aeronautics and Space Administration and the National Science Foundation This work made use of v2 2 1 of the Binary Population and Spectral Synthesis BPASS models as described in Eldridge et al 2017 and Stanway & Eldridge 2018https://www.aanda.org/articles/aa/abs/2025/04/aa53479-24/aa53479-24.htm
The Role of Language in Immigration Policy: How Racializing Discourses Challenge Social Equity in Public Administration
No full textDissertation submitted to the College of Public Affairs of The University of
Baltimore in partial fulfillment of
the requirements for the degree
of Doctor of Public AdministrationD.P.A. -- The University of
Baltimore, 202
Advocacy for Equity: How Two Transnational Feminist Activists Utilize Parrhesiastic Resistance to Champion for Climate Action and Access to Education
No full textParrhesia is the rhetorical act of speaking truth to power even when doing so is risky to the speaker, and has been integral to Western thought and practice ever since it arose alongside democracy and rhetoric and ancient Athens in the fourth century BCE. When a parrhesiastes speaks, it is often because some truth value is being violated and the outrage at this violation causes her to speak out. The sense of injustice and the choice to speak out regardless of the risk may be experienced as a privately made decision, but generally reflects a commonly accepted value that is not being enacted, acknowledged or manifested sufficiently. However, because parrhesia is often required for marginalized or silenced people to speak out at all, there is a need to understand how this works so we can both acknowledge the great risks certain speakers take in speaking and show how to enact these moments of resistance to power when that may be the only rhetorical means possible. This paper analyzes the rhetorical agency of two activists as parrhesiastes to encourage climate action and equal access to education across the globe. Specifically, I use a rhetorical situation analysis to analyze two speeches given by Greta Thunberg and Malala Yousafzai to the United Nations when they were both sixteen years old. This paper attempts to tie in transnational feminist theory and social movement studies to study Thunberg's and Yousafzai's sources of persuasion, their use of parrhesia to enhance their message, and their place as activists working across transnational boundaries
AN ECOFEMINIST READING AND CRITIQUE OF EDITH WHARTONS' SUMMER (1917) AND CATERINA ALBERT i PARADÍS' SOLITUDE (1905)
No full textThis study draws upon ecofeminist theory to analyze two early twentieth-century novels, Edith Wharton’s Summer (1917) and Caterina Albert i Paradís’ Solitude (1905). These novels challenge the definition of relationship between women and nature – as nature changes, the female characters change as well. A gendered ecological reading and an ecofeminist critique of these two novels uncovers the power structures and the limitations that rural and natural environments have for women, and how they restrict women’s experience in nature. This project intends to answer the questions: How does Ecofeminism help the reader to see how women perceive and experience nature and the environment differently than men? How useful it is to compare the degradation of nature with the degradation of women in patriarchal and dualistic societies? How does culture influence the way coming-of-age novels portray female characters in relation to nature? The study answers these questions by following an anti-essentialism, anti-dualism and anti-anthropocentrism approach. The comparative reading shows that ecofeminism is a useful approach and demonstrates the inferiority and limitations of women in relation to the environment
Intergenerational Housing Poster
No full textThis research explores the development of an intergenerational housing model on campus to address housing insecurity, social isolation, and limited intergenerational understanding—challenges that affect both college students and older adults, especially within the LGBTQ+ community. By fostering shared living spaces between students and older adults, the project aims to reduce loneliness and financial hardship while promoting mutual support. Using interviews, surveys, and case studies, we examine the benefits and barriers of implementation. We also consider how university policies, funding, and community partnerships can support this model. Ultimately, this initiative offers a sustainable, inclusive approach to housing that strengthens community and promotes lifelong learning