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Outflowing photoionized plasma in Circinus X-1 using the high-resolution X-ray spectrometer Resolve onboard XRISM and the radiative transfer code cloudy
No full textHigh-resolution X-ray spectroscopy is a key to understanding the mass inflow and outflow of compact objects. Spectral lines carry information about the ionization, density, and velocity structures through their intensity ratios and profiles. They are formed in non-local thermodynamic equilibrium conditions under the intense radiation field from the compact objects, thus radiative transfer (RT) calculation is a requisite for proper interpretations. We present such a study for a low-mass X-ray binary, Circinus X-1, from which the P Cygni profile was discovered using the X-ray grating spectrometer onboard Chandra. We observed the source using the X-ray microcalorimeter onboard XRISM at an orbital phase of 0.93-0.97 and revealed many spectral features unidentified before; the higher series transitions (n to 1; n > 2) of highly-ionized (H- and He-like) S, Ca, Ar, and Fe in emission and absorption, the Fe K{\alpha} and K\b{eta} inner-shell excitation absorption of mildly-ionized (O- to Li-like) Fe, and resolved fine-structure level transitions in the Fe Ly{\alpha} and He{\alpha} complexes. They blend with each other at different velocity shifts on top of apparently variable continuum emission that changed its flux by an order of magnitude within a 70 ks telescope time. Despite such complexity in the observed spectra, most of them can be explained by a simple model consisting of the photoionized plasma outflowing at ~300 km s-1 and the variable blocking material in the line of sight of the incident continuum emission from the accretion disk. We demonstrate this with the aid of the RT code cloudy for the line ratio diagnostics and spectral fitting. We further constrain the physical parameters of the outflow and argue that the outflow is launched close to the outer edge of the accretion disk and can be driven radiatively by being assisted by the line force calculated using the RT simulation.This work was supported by the JSPS Core-to-Core Program (grant number: JPJSCCA20220002). MS acknowledges support by Grantsin-Aid for Scientific Research 19K14762 and 23K03459 from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan. Part of this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. The material is based upon work supported by NASA under award number 80GSFC21M0002. This research made use of the JAXA’s high-performance computing system JSS3.https://arxiv.org/abs/2503.0825
3D-Printed Microfluidic-Based Cell Culture System With Analysis to Investigate Macrophage Activation
No full textIn this paper, we describe the development of 3D-printed microfluidic cell culture devices that can be coupled with a circulation system to study the dynamics of both intracellular and extracellular (release) processes. Key to this approach is the ability to quantitate key analytes on a minutes timescale with either on-line (in this study, quantitating nitric oxide production using an amperometric flow cell) or off-line (in this work, quantitating intracellular itaconate production with LC/MS) analytical measurements. To demonstrate the usefulness of this approach, we chose to study macrophage polarization as a function of the extracellular matrix (silk) fiber size, a major area of research in tissue engineering. It was found that the use of larger fibers (1280 nm vs. smaller 512 nm fibers) led to increases in the production of both nitric oxide and itaconate. These findings set the foundation for future research for the creation of finely tuned microfluidic 3D cell culture approaches in areas where flow and the extracellular matrix play a significant role in barrier transport and where integrated analysis of key markers is needed.We would like to acknowledge funding from the National Institutes of Health for both C.C. (NIGMS, 1R35GM146779) and R.S.M. (NINDS, 2R01NS105888-06A1).https://onlinelibrary.wiley.com/doi/abs/10.1002/elps.810
Applying Social Community Identity and Spatial Theory to Extend Our Understanding of Ala al-Din Khammas: The Warrior-Scholar Who Trained Saddam Hussein’s Military Leaders
No full textAla’ al-Din Khammas is unique among Saddam Hussein’s generals interviewed in 2009 by U.S. military officials for his prolific publications produced while in Iraq’s military and after his retirement. His military manuals developed during the Iran-Iraq War (1980-1988) and distributed to Iraq’s field commanders, would be instrumental in stabilizing the southern Basra front. Khammas’ is also rare among Saddam’s officers for his effort to introduce American military works to Iraqi military officers. This study investigates Khammas’ intellectual imprint on Iraqi officers that would later confront American forces in Operations Desert Storm and Iraqi Freedom. This qualitative interpretive study critically examines Khammas’ magnum opus, The Arab Art of War (1999) which argues that Arabs have their own distinct art of war worthy of careful study developed in the 7th century. It experiments with identity and spatial relationship theories of Anderson (2016), and Tuan (1990) as frameworks in a novel approach to military analysis and expands our understanding of Khammas himself and his argument of a distinct Arab art of war. Applying these theoretical frameworks make up for Khammas intense focus on battlefield tactics and identifies two overarching principles embedded throughout his work, the use of extreme contrasts in terrain and how a changing Arab identity enabled a 7th century hybrid combination of tribal and conventional war that can be called a distinct all-encompassing Arab art of war
Introduction: law in a changing climate
No full textAs societies grapple with mitigating or adapting to climate change, law plays a prominent role in the social relations that constitute a response. In this essay, we briefly review of the many different perspectives on law and climate change offered by the authors in this special issue of Law and Society Review. From transnational human rights activism to constitutional litigation to local practices and all around the globe, both the powerful and the marginalized draw on legal institutions and actors in multiple arenas and at multiple scales to address the consequences of climate change. Together, these articles show that law is not confined to courtrooms or judicial systems or regulations; rather, law offers both limitations and opportunities in the ongoing struggle over climate change.https://www.cambridge.org/core/journals/law-and-society-review/article/introduction-law-in-a-changing-climate/BAF4549A3E93AC2183CB9386D5C2AE7
Time Series Classification of Supraglacial Lakes Evolution over Greenland Ice Sheet
No full text2024 International Conference on Machine Learning and Applications (ICMLA), December 18-20, 2024, Miami, FloridaThe Greenland Ice Sheet (GrIS) has emerged as a significant contributor to global sea level rise, primarily due to increased meltwater runoff. Supraglacial lakes, which form on the ice sheet surface during the summer months, can impact ice sheet dynamics and mass loss; thus, better understanding these lakes' seasonal evolution and dynamics is an important task. This study presents a computation-ally efficient time series classification approach that uses Gaussian Mixture Models (GMMs) of the Reconstructed Phase Spaces (RPSs) to identify supraglacial lakes based on their seasonal evolution: 1) those that refreeze at the end of the melt season, 2) those that drain during the melt season, and 3) those that become buried, remaining liquid insulated a few meters beneath the surface. Our approach uses time series data from the Sentinel-l and Sentinel-2 satellites, which utilize microwave and visible radiation, respectively. Evaluated on a GrIS-wide dataset, the RPS-GMM model, trained on a single representative sample per class, achieves 85.46% accuracy with Sentinel-l data alone and 89.70% with combined Sentinel-l and Sentinel-2 data. This performance significantly surpasses existing machine learning and deep learning models which require a large training data. The results demonstrate the robustness of the RPS-GMM model in capturing the complex temporal dynamics of supraglaciallakes with minimal training data.This work is supported by iHARP: NSF HDR Institute for Harnessing Data and Model Revolution in the Polar Regions (Award# 2118285). The views expressed in this work do not necessarily reflect the policies of the NSF, and endorsement by the Federal Government should not be inferred.https://ieeexplore.ieee.org/document/1090328
Comparison of Several Neural Network-Enhanced Sub-Grid Scale Stress Models for Meso-Scale Hurricane Boundary Layer Flow Simulation
No full textAIAA SCITECH 2025, 6-10 January 2025, Orlando, FLThe complicated energy cascade and backscatter dynamics present a challenge when studying turbulent flows in storms at the meso-scale. When performing standard large-eddy simulations (LES), sub-grid scale (SGS) stress models usually fail to consider energy backscatter. These models assume that kinetic energy only moves continuously from larger to smaller scales. However, coherent energy backscatter structures exist when analyzing hurricane boundary layer flows at the meso-scale. Our recent research has shown that machine-learning SGS models trained with high-resolution data can effectively forecast forward and backward energy transfers in meso-scale hurricane-like vortex flows. Therein, physical and geometrical invariances were introduced to better represent flow physics. This further improved the predictability and generalizability of machine-learning-enhanced SGS models. In this study, we compare the performance of several machine-learning-enhanced SGS models, especially those based on neural networks (NNs), with varying physical and geometrical invariance embedding levels for SGS stress modeling in an a priori sense, which sets the cornerstone for ongoing a posteriori tests of NN models.The hardware used in the computational studies is part of the UMBC High Performance Computing Facility (HPCF). The facility is supported by the U.S. National Science Foundation through the MRI program (grant nos. CNS-0821258, CNS-1228778, and OAC-1726023) and the SCREMS program (grant no. DMS-0821311), with additional substantial support from the University of Maryland, Baltimore County (UMBC). Hasan and Yu are grateful to Dr. Heng Xiao for the constructive discussionshttps://arc.aiaa.org/doi/10.2514/6.2025-221
Integrated AHB to APB Bridge Using Raspberry Pi and Artix-7 FPGA
No full textThis project focuses on the design and implementation of an AHB to APB Bridge for efficient communication in System-on-Chip (SoC) architectures. The Advanced High-performance Bus (AHB) is used for high-speed operations, typically connecting processors and memory, while the Advanced Peripheral Bus (APB) is optimized for low-power, low-speed peripheral devices. The AHB to APB Bridge serves as an interface that converts complex, high-speed AHB transactions into simpler, single-cycle APB transactions, enabling seamless data transfer between fast components and slower peripherals. The bridge manages clock domain synchronization, transaction conversion, and flow control, ensuring compatibility between AHB's burst transfers and APB's non-pipelined protocol. Implemented in Verilog and simulated on FPGA using Xilinx Vivado, this bridge design provides a robust solution for integrating high-performance and low-power components within a single SoC. This project also evaluates the bridge's functionality and performance through testbenches covering various operational scenarios, validating its efficiency in handling diverse system requirements.http://arxiv.org/abs/2501.0114
Simon's algorithm in the NISQ cloud
No full textSimon’s algorithm was one of the first to demonstrate a genuine quantum advantage in solving a problem. The algorithm, however, assumes access to fault-tolerant qubits. In our work, we use Simon’s algorithm to benchmark the error rates of devices currently available in the “quantum cloud”. As a main result, we objectively compare the different physical platforms made available by IBM and IonQ. Our study highlights the importance of understanding the device architectures and topologies when transpiling quantum algorithms onto hardware. For instance, we demonstrate that two-qubit operations on spatially separated qubits on superconducting chips should be avoided.S.D. acknowledges support from the John Templeton Foundation under Grant No. 62422. IBM Quantum services were used for this work. The views expressed are those of the authors and do not reflect the official policy or position of IBM or the IBM Quantum team.https://www.mdpi.com/1099-4300/27/7/65
Beyoncé Week Projects Created by Technology Law Students
No full textDuring our Beyoncé Week Project, undergraduate Technology Law students at University of Maryland, Baltimore County (UMBC) examine legal issues relating to topics, businesses, and industries they love. We interview experts, creators, and businesspeople around the world, and then share their insights and stories.https://www.beyonceweekumbc.org
The 10 October 2024 geomagnetic storm may have caused the premature reentry of a Starlink satellite
No full textIn this short communication, we qualitatively analyze possible effects of the 10 October 2024 geomagnetic storm on accelerating the reentry of a Starlink satellite from very low-Earth orbit (VLEO). The storm took place near the maximum of solar cycle (SC) 25, which has shown to be more intense than SC24. Based on preliminary geomagnetic indices, the 10 October 2024, along with the 10 May 2024, were the most intense events since the well-known Halloween storms of October/November 2003. By looking at a preliminary version of the Dst index and altitudes along with velocities extracted from two-line element (TLE) data of the Starlink-1089 (SL-1089) satellite, we observe a possible connection between storm main phase onset and a sharp decay of SL-1089. The satellite was predicted to reenter on 22 October, but it reentered on 12 October, 10 days before schedule. The sharp altitude decay of SL-1089 revealed by TLE data coincides with the storm main phase onset. We compare the deorbiting altitudes of another three satellites during different geomagnetic conditions and observe that the day difference between actual and predicted reentries increases for periods with higher geomagnetic activity. Therefore, we call for future research to establish the eventual causal relationship between storm occurrence and satellite orbital decay. As predicted by previous works, SC25 is already producing extreme geomagnetic storms with unprecedented satellite orbital drag effects and consequences for current megaconstellations in VLEO.DMO and EZ thank the financial support provided by the NASA HGIO program through grant 80NSSC22K0756. DMO and EZ also acknowledge financial support by NASA’s Space Weather Science Applications Operations 2 Research. DN’s involvement in space weather research is sustained by the Ministry of Education, Government of India and a private philanthropic grant at the Center of Excellence in Space Sciences India, IISER Kolkatahttps://www.frontiersin.org/journals/astronomy-and-space-sciences/articles/10.3389/fspas.2024.1522139/ful