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Timing and Spectral Evolution of the Magnetar 1E 1841-045 in Outburst
No full textWe present the timing and spectral analyses of the NICER, NuSTAR, and IXPE observations of the magnetar 1E 1841-045 covering 82 days following its August 2024 bursting activity as well as radio observations utilizing MeerKAT and Effelsberg. We supplement our study with a historical NuSTAR and all 2024 pre-outburst NICER observations. The outburst is marked by an X-ray flux enhancement of a factor 1.6 compared to the historical level, predominantly driven by a newly-formed non-thermal emitting component with a photon index Γ=1.5. This flux showed a 20% decay at the end of our monitoring campaign. The radio monitoring did not reveal any pulsed radio emission with an upper-limit of 20 mJy and 50 mJy ms on the mean flux density and single pulse fluence, respectively. We detect a spin-up glitch at outburst onset with a Δν=6.1×10⁻⁸ Hz and a Δν˙=−1.4×10⁻¹ Hz s⁻¹⁴, consistent with the near-universality of this behavior among the continuously-monitored magnetars. Most intriguingly, the 1E 1841-045 2-10 keV pulse profile is markedly different compared to pre-outburst; it shows a new, narrow (0.1 cycles) peak that appears to shift towards merging with the main, persistently-present, pulse. This is the second case of pulse-peak migration observed in magnetars after SGR 1830−0645, and the two sources exhibit a similar rate of phase shift. This implies that this phenomenon is not unique and might present itself in the broader population. The newly-formed peak for 1E 1841-045 is non-thermal, with emission extending to ≳20 keV, in contrast to the case of SGR 1830−0645. Our results are consistent with an untwisting magnetic field bundle with migration towards the magnetic pole, perhaps accompanied by plastic motion of the crust.This material is based upon work supported by the National Aeronautics and Space Administration under Agreement No. 80GSFC24M0006 issued through the Office of Science. G.Y. acknowledge support through NASA grants 80NSSC21K1997, 80NSSC23K1114, and 80NSSC25K7257, which are partly funding PhD students R.S. and A.v.K., and postdoctoral fellow A.M. M.G.B. thanks NASA for generous support under awards 80NSSC24K0589 and 80NSSC25K7257. W.C.G.H. acknowledges support through grant 80NSSC23K0078 from NASA. M. Ng is a Fonds de Recherche du Quebec ? Nature et Technologies (FRQNT) postdoctoral fellow. L.G.S. is a Lise Meitner Group Leader, and together with M.L.B. acknowledge support from the Max Planck Society. The MeerKAT telescope is operated by the South African Radio Astronomy Observatory, which is a facility of the National Research Foundation, an agency of the Department of Science and Innovation. This work has made use of the ?MPIfR S-band receiver system? designed, constructed, and maintained by funding of the MPI f?ur Radioastronomy and the Max Planck Society. Observations used PTUSE for data acquisition, storage, and analysis which was partly funded by the Max-Planck-Institut f?ur Radioastronomie (MPIfR). Based on observations with the 100-m telescope of the MPIfR (Max-Planck-Institut f?ur Radioastronomie) at Effelsberg. The UBB receiver and the Effelsberg Direct Digitisation (EDD) system are developed and maintained by the Max Planck Institute for Radioastronomy (MPIfR) and are funded by the Max Planck Gesellschaft (MPG). G.Y. thanks Alexander Philippov for the enlightening discussions pertaining to the results presented in this manuscript.http://arxiv.org/abs/2502.2007
CAM-Seg: A Continuous-valued Embedding Approach for Semantic Image Generation
No full textTraditional transformer-based semantic segmentation relies on quantized embeddings. However, our analysis reveals that autoencoder accuracy on segmentation mask using quantized embeddings (e.g. VQ-VAE) is 8% lower than continuous-valued embeddings (e.g. KL-VAE). Motivated by this, we propose a continuous-valued embedding framework for semantic segmentation. By reformulating semantic mask generation as a continuous image-to-embedding diffusion process, our approach eliminates the need for discrete latent representations while preserving fine-grained spatial and semantic details. Our key contribution includes a diffusion-guided autoregressive transformer that learns a continuous semantic embedding space by modeling long-range dependencies in image features. Our framework contains a unified architecture combining a VAE encoder for continuous feature extraction, a diffusion-guided transformer for conditioned embedding generation, and a VAE decoder for semantic mask reconstruction. Our setting facilitates zero-shot domain adaptation capabilities enabled by the continuity of the embedding space. Experiments across diverse datasets (e.g., Cityscapes and domain-shifted variants) demonstrate state-of-the-art robustness to distribution shifts, including adverse weather (e.g., fog, snow) and viewpoint variations. Our model also exhibits strong noise resilience, achieving robust performance (≈ 95% AP compared to baseline) under gaussian noise, moderate motion blur, and moderate brightness/contrast variations, while experiencing only a moderate impact (≈ 90% AP compared to baseline) from 50% salt and pepper noise, saturation and hue shifts. Code available: this https URLThis work has been partially supported by U.S. Army Grant #W911NF2120076, U.S. Army Grant #W911NF2410367, ONR Grant #N00014-23-1-2119, NSF CAREER Award #1750936, NSF REU Site Grant #2050999, and NSF CNS EAGER Grant #2233879.https://arxiv.org/abs/2503.1561
Data-driven Fuzzy Control for Time-Optimal Aggressive Trajectory Following
No full textOptimal trajectories that minimize a user-defined cost function in dynamic systems require the solution of a two-point boundary value problem. The optimization process yields an optimal control sequence that depends on the initial conditions and system parameters. However, the optimal sequence may result in undesirable behavior if the system's initial conditions and parameters are erroneous. This work presents a data-driven fuzzy controller synthesis framework that is guided by a time-optimal trajectory for multicopter tracking problems. In particular, we consider an aggressive maneuver consisting of a mid-air flip and generate a time-optimal trajectory by numerically solving the two-point boundary value problem. A fuzzy controller consisting of a stabilizing controller near hover conditions and an autoregressive moving average (ARMA) controller, trained to mimic the time-optimal aggressive trajectory, is constructed using the Takagi-Sugeno fuzzy framework.http://arxiv.org/abs/2504.0650
Local Journalism in the Shadow of the Federal City
No full textBethesda Magazine and its news website Bethesda Today refocus on their core market as a new federal administration seeks to remake the Washington DC metropolitan area. Sunil Dasgupta talks with publisher Jennifer Farkas and editor Jule Rasicot about the road ahead for local journalism in Bethesda and Montgomery County, MD. Newly in public domain music by Clara Smith and The Troubadours.https://open.spotify.com/episode/4UodBOtn4Qto8ELUAUvHS
Exploring CS Education Policy Through the Lens of State Governance Models: Access, Accountability and Authority
No full textSIGCSETS 2025: Proceedings of the 56th ACM Technical Symposium on Computer Science Education V. 2, Pittsburgh PA USA, 26 February 2025- 1 March 2025Computer science (CS) education policy efforts have accelerated since 2016 through the work of various governmental, advocacy, and CS-focused organizations. CS policy implementation is typically led by CS education state supervisors (CSEdSS) at state education agencies (SEA), whose responsibilities may encompass training CS teachers, allocating resources, and informing teacher certification. Despite efforts to expand K-12 CS education through a set of 10 nationally-recommended policies, equity issues persist in terms of access for historically marginalized students to learn CS. Moreover, while states may adopt the same policy, each state has their own model of state education governance (SEG). These models determine authority and accountability - how education decision-making and policies are made and implemented. This study explores the relationship between SEG models and impact of CS education policy implementation by exploring the average rate of growth in access to high school (HS) CS and percent of CS education policies adopted across SEG models. Data sources include publicly available data of secondary CS access and CSEdSS survey and focus groups. Preliminary findings indicate the need to consider SEG models when enacting CS education policy to balance accountability with authority when enacting CS education policy related to expanding equitable and accessible K-12 CS education.This research is supported by the National Science Foundation Grant #2239481.https://dl.acm.org/doi/10.1145/3641555.370518
Sleep Necessities: An Activity Book to Better Rest
No full textSleep is one of the most beneficial and influential factors in everyone’s lives. Without it, no one could operate. Unfortunately, many people receive inadequate sleep, which affects overall health and higher executive functions needed to perform daily tasks. This issue can especially be seen in college students working toward their respective degrees. For instance, research shows that chronic sleep deprivation may result in low grade point averages and lower chances of graduating (Chen & Chen, 2019). The submitted, self-created activities book shares information based on the biological factors behind sleep, what affects sleep, what sleep affects, and how to improve it. The items are designed for students to understand sleep and its significance, the fundamentals of sleep’s neurobiological mechanisms, and to improve sleep routines. In reaching the goal, the book provides various sections on information on sleep, its neuro-biopsychological aspects, tips for enhancing sleep, and activities for mind-stimulating recreation - sleep-related scales, color page, and more - to have fun when absorbing the information and have a visual representation of the structures. Currently, a copy of the self-published book is available at the Stevenson University Wellness Center
Mach Number Scaling of Foreshock Magnetic Fluctuations at Quasi-parallel Bow Shocks and Their Role in Magnetospheric Driving Throughout the Solar System
No full textUpstream of quasi-parallel bow shocks, reflected ions generate ion–ion instabilities. The resulting magnetic fluctuations can advect through the shock and interact with planetary magnetospheres. The amplitude of magnetic fluctuations depends on the strength of the shock, quantified by the Alfvén Mach number (MA), which is the ratio of solar wind velocity to the local Alfvén velocity. With increasing heliocentric distance, the solar wind MA generally increases, such that Mercury typically experiences a lower MA ~ 5 compared to Earth (MA ~ 8), and Mars a slightly higher MA ~ 9. Farther out in the solar system, Saturn has even higher MA (~10). However, the solar wind flow is highly irregular, and on top of solar cycle variations these values for average MA at each planet do not capture extreme events. Statistical analysis of OMNIWeb observations from 2015 to 2023 shows that sustained (30 minutes or more) high MA (30–100) occurs at Earth about once a month. Using a selection of events in the ion foreshock regions of Mercury, Earth, Mars, and Saturn, a linear scaling is calculated for the maximum magnetic fluctuation amplitude as a function of MA. The resulting slope is ~0.2. Based on the dominant fluctuation frequency for the largest-amplitude events at each planet, it is found that Mars exists in a special regime where the wave period of the magnetic fluctuations can be similar to or longer than the magnetospheric convection timescale, making Mars more susceptible to space weather effects associated with foreshock fluctuations.Funding for this work is provided by MMS Early Career Award 80NSSC25K7352 and the Exosphere, Ionosphere, Magnetosphere Modeling (EIMM) program.https://iopscience.iop.org/article/10.3847/1538-4357/ada44
The Impacts of U.S. Department of Defense Humanitarian Civic Assistance Projects on Host Nation Community Resilience.
No full textThe US Department of Defense's Humanitarian Civic Assistance (HCA) projects are an important tool that enhances community resilience in partner nations. My research on the impacts of HCA projects on resilience in Togo and Tunisia shows that proximity to HCA projects correlates with better access to medical care, suggesting a positive impact on community resilience. The DOD’s shift away from humanitarian assistance activities resulted in reduced funding for HCA projects. However, HCA continues to be an important assistance tool. HCA project impacts on community resilience can be improved by additional funding, improved planning, and closer attention to the local context
