bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comprehensive Radiative MHD Simulations of Eruptive Flares above Collisional Polarity Inversion Lines
Authors: Rempel Matthias , Chintzoglou Georgios , Cheung Mark C. M. , Fan Yuhong , Kleint Lucia 
Published: September 2023

Abstract
We present a new simulation setup using the MURaM radiative MHD code that allows the study of the formation of collisional polarity inversion lines (cPILs) in the photosphere and the coronal response including flares. In this scheme, we start with a bipolar sunspot configuration and set the spots on collision course by imposing the appropriate velocity field at the footpoints in the subphotospheric boundary. We produce different setups with the same initial spot separation by varying physical parameters such as the collision speed and minimum collision distance. While all setups lead to the formation of an EUV and X-ray sigmoid structure, only the cases with a close passing of the spots cause flares and mass eruptions. The energy release is in the 1–2 × 1031 erg range, putting the simulated flares into the upper C-class to lower M-class range of GOES X-ray 1–8 Å flux. While the setup with the more distant passing of the spots does not lead to a flare, the corona is nonetheless substantially heated, suggesting noneruptive energy-release mechanisms. We focus our discussion on two particular setups that differ in spot coherence and resulting cPIL length persistence. We find different timings in the transition from a sheared magnetic arcade to magnetic flux rope (MFR); the setup with a large length but shorter duration cPIL produces a MFR during the eruption, while the MFR is preexisting in the setup with a large length and longer duration cPIL. While both result in flares of comparable strength and the eruption of a coronal mass ejection, the setup with preexisting MFR (and embedded filament) leads to an MFR eruption with a larger mass content.
A High-mass, Young Star-forming Core Escaping from Its Parental Filament
Authors: Ren 任 Zhiyuan 致远 , Chen 陈 Xi 曦 , Liu 刘 Tie 铁 , Mannfors Emma , Bronfman Leonardo , Xu 许 Fengwei 峰玮 , Feng 冯 Siyi 思轶 , Liu 刘 Hongli 洪礼 , Meng 孟 Fanyi 繁一 , Stutz Amelia M. , Li 李 Shanghuo 尚活 , Lee Chang Won , Wang 王 Ke 科 , Zhou 周 Jianwen 建文 , Li 李 Di 菂 , Wang 王 Chen 晨 , Eswaraiah Chakali , Tej Anandmayee , Chen 陈 Long-Fei 龙飞 , Shi 石 Hui 惠 
Published: September 2023

Abstract
We studied the unique kinematic properties in massive filament G352.63-1.07 at 103 au spatial scale with the dense molecular tracers observed with the Atacama Large Millimeter/submillimeter Array. We find the central massive core M1 (12 M
⊙) being separated from the surrounding filament with a velocity difference of

v
−

v

¯

sys

=
−
2

km

s

−
1

and a transverse separation within 3″. Meanwhile, as shown in multiple dense-gas tracers, M1 has a spatial extension closely aligned with the main filament and is connected to the filament toward both its ends. M1 thus represents a very beginning state for a massive, young star-forming core escaping from the parental filament, within a timescale of ∼4000 yr. Based on its kinetic energy (3.5 × 1044 erg), the core escape is unlikely solely due to the original filament motion or magnetic field but requires more energetic events such as a rapid intense anisotropic collapse. The released energy also seems to noticeably increase the environmental turbulence. This may help the filament to become stabilized again.
AstroSat View of the Neutron Star Low-mass X-Ray Binary GX 340+0
Authors: Bhargava Yash , Bhattacharyya Sudip , Homan Jeroen , Pahari Mayukh 
Published: September 2023

Abstract
Understanding the spectral evolution along the “Z”-shaped track in the hardness–intensity diagram of Z sources, which are a class of luminous neutron star low-mass X-ray binaries, is crucial to probe accretion processes close to the neutron star. Here, we study the horizontal branch (HB) and the normal branch (NB) of the Z source GX 340+0 using AstroSat data. We find that the HB and the NB appear as two different types of X-ray intensity dips, which can appear in any sequence and with various depths. Our 0.8–25 keV spectra of dips and the hard apex can be modeled by the emissions from an accretion disk, a Comptonizing corona covering the inner disk, and the neutron star surface. We find that as the source moves onto the HB, the corona is replenished and energized by the disk and a reduced amount of disk matter reaches the neutron star surface. We also conclude that quasiperiodic oscillations during HB/NB are strongly associated with the corona and explain the evolution of strength and hard lag of this timing feature using the estimated coronal optical depth evolution.
Constraints on Strong Phase Transitions in Neutron Stars
Authors: Gorda T. , Hebeler K. , Kurkela A. , Schwenk A. , Vuorinen A. 
Published: September 2023

Abstract
We study current bounds on strong first-order phase transitions (PTs) along the equation of state (EOS) of dense strongly interacting matter in neutron stars, under the simplifying assumption that on either side of the PT, the EOS can be approximated by a simple polytropic form. We construct a large ensemble of possible EOSs of this form, anchor them to chiral effective field theory calculations at nuclear density and perturbative Quantum Chromodynamics at high densities, and subject them to astrophysical constraints from high-mass pulsars and gravitational-wave observations. Within this setup, we find that a PT permits neutron-star solutions with larger radii, but only if the transition begins below twice nuclear saturation density. We also identify a large parameter space of allowed PTs currently unexplored by numerical-relativity studies. Additionally, we locate a small region of parameter space allowing twin-star solutions, though we find them to only marginally pass the current astrophysical constraints. Finally, we find that sizeable cores of high-density matter beyond the PT may be located in the centers of some stable neutron stars, primarily those with larger masses.
Quasiperiodic Oscillation in Short Gamma-Ray Bursts from Black Hole–Neutron Star Mergers
Authors: Li 李 Yan 彦 , Shen 申 Rong-Feng 荣锋 , Zhang 张 Bin-Bin 彬彬 
Published: September 2023

Abstract
Short-duration gamma-ray bursts (sGRBs) are commonly attributed to the mergers of double neutron stars (NSs) or the mergers of a neutron star with a black hole (BH). While the former scenario was confirmed by the event GW170817, the latter remains elusive. Here, we consider the latter scenario in which an NS is tidally disrupted by a fast-spinning low-mass BH and the accretion onto the BH launches a relativistic jet and hence produces an sGRB. The merging binary’s orbit is likely misaligned with the BH’s spin. Hence, the Lense–Thirring precession around the BH may cause a hyperaccreting thick disk to precess in a solid-body manner. We propose that a jet, initially aligned with the BH spin, is deflected and collimated by the wind from the disk, therefore being forced to precess along with the disk. This would result in a quasiperiodic oscillation or modulation in the gamma-ray light curve of the sGRB, with a quasi-period of ∼0.01–0.1 s. The appearance of the modulation may be delayed respective to the triggering of the light curve. This feature, unique to the BH–NS merger, may have already revealed itself in a few observed sGRBs (such as GRB 130310A), and it carries the spin–orbit orientation information of the merging system. Identification of this feature would be a new approach to reveal spin–orbit misaligned merging BH–NS systems, which are likely missed by the current gravitational-wave searching strategy that is principally targeting aligned systems.
The Effects of Nonequilibrium Velocity Distributions on Alfvén Ion-cyclotron Waves in the Solar Wind
Authors: Walters Jada , Klein Kristopher G. , Lichko Emily , Stevens Michael L. , Verscharen Daniel , Chandran Benjamin D. G. 
Published: September 2023

Abstract
In this work, we investigate how the complex structure found in solar wind proton velocity distribution functions (VDFs), rather than the commonly assumed two-component bi-Maxwellian structure, affects the onset and evolution of parallel-propagating microinstabilities. We use the Arbitrary Linear Plasma Solver, a numerical dispersion solver, to find the real frequencies and growth/damping rates of the Alfvén modes calculated for proton VDFs extracted from Wind spacecraft observations of the solar wind. We compare this wave behavior to that obtained by applying the same procedure to core-and-beam bi-Maxwellian fits of the Wind proton VDFs. We find several significant differences in the plasma waves obtained for the extracted data and bi-Maxwellian fits, including a strong dependence of the growth/damping rate on the shape of the VDF. By applying the quasilinear diffusion operator to these VDFs, we pinpoint resonantly interacting regions in velocity space where differences in VDF structure significantly affect the wave growth and damping rates. This demonstration of the sensitive dependence of Alfvén mode behavior on VDF structure may explain why the Alfvén ion-cyclotron instability thresholds predicted by linear theory for bi-Maxwellian models of solar wind proton background VDFs do not entirely constrain spacecraft observations of solar wind proton VDFs, such as those made by the Wind spacecraft.
Secondary Proton Beam Instability in a Turbulent Solar Wind at 50 R
⊙
Authors: Markovskii S. A. , Vasquez Bernard J. 
Published: September 2023

Abstract
We investigate a secondary proton beam instability coexisting with the ambient solar wind turbulence at 50 R
☉. Three-dimensional hybrid numerical simulations (particle ions and a quasi-neutralizing electron fluid) are carried out with the plasma parameters in the observed range. In the turbulent background, the particle distribution function, in particular the slope of the “bump-on-tail” responsible for the instability, is time-dependent and inhomogeneous. The presence of the turbulence substantially reduces the growth rate and saturation level of the instability. We derive magnetic power spectra from the observational data and perform a statistical analysis to evaluate the average turbulence intensity at 50 R
☉. This information is used to link the observed frequency spectrum to the wavenumber spectrum in the simulations. We verify that Taylor’s frozen-in hypothesis is valid for this purpose to a sufficient extent. To reproduce the typical magnetic power spectrum of the instability observed concurrently with the background turbulence, an artificial spacecraft probe is run through the simulation box. The thermal-ion instabilities are often seen as power elevations in the kinetic range of scales above an extrapolation of the turbulence spectrum from larger scales. We show that the elevated power in the simulations is much higher than the background level. Therefore, the turbulence at the average intensity does not obscure the secondary proton beam instability, as opposed to the solar wind at 1 au, in which the ambient turbulence typically obscures thermal-ion instabilities.
Deciphering the Morphological Origins of X-shaped Radio Galaxies: Numerical Modeling of Backflow versus Jet Reorientation
Authors: Giri Gourab , Vaidya Bhargav , Fendt Christian 
Published: September 2023

Abstract
X-shaped radio galaxies (XRGs) develop when certain extragalactic jets deviate from their propagation path. An asymmetric ambient medium (backflow model) or complex active galactic nucleus activity (jet-reorientation model) enforcing the jet direction to deviate may cause these structures. In this context, the present investigation focuses on the modeling of XRGs by performing 3D relativistic magnetohydrodynamic simulations. We implement different jet-propagation models applying an initially identical jet-ambient medium configuration to understand distinctive features. This study, the first of its kind, demonstrates that all adopted models produce XRGs with notable properties, thereby challenging the notion of a universal model. Jet reorientation naturally explains several contentious properties of XRGs, including wing alignment along the ambient medium’s primary axis, development of collimated lobes, and the formation of noticeably longer wings than active lobes. These XRGs disrupt the cluster medium by generating isotropic shocks and channeling more energy than in the backflow scenario. Our synthetic thermal X-ray maps of the cluster medium reveal four clear elongated cavities associated with the wing-lobe alignment, regardless of projection effects, but they affect their age estimation. We show that the depth and geometric alignment of the evolved cavities may qualify as promising characteristics of XRGs, which may be used to disentangle different formation scenarios.
Tidally Excited Inertial Waves in Stars and Planets: Exploring the Frequency-dependent and Averaged Dissipation with Nonlinear Simulations
Authors: Astoul Aurélie , Barker Adrian J. 
Published: September 2023

Abstract
We simulate the nonlinear hydrodynamical evolution of tidally excited inertial waves in convective envelopes of rotating stars and giant planets modeled as spherical shells containing incompressible, viscous, and adiabatically stratified fluid. This model is relevant for studying tidal interactions between close-in planets and their stars, as well as close low-mass star binaries. We explore in detail the frequency-dependent tidal dissipation rates obtained from an extensive suite of numerical simulations, which we compare with linear theory, including with the widely employed frequency-averaged formalism to represent inertial wave dissipation. We demonstrate that the frequency-averaged predictions appear to be quite robust and are approximately reproduced in our nonlinear simulations spanning the frequency range of inertial waves as we vary the convective envelope thickness, tidal amplitude, and Ekman number. Yet, we find nonlinear simulations can produce significant differences with linear theory for a given tidal frequency (potentially by orders of magnitude), largely due to tidal generation of differential rotation and its effects on the waves. Since the dissipation in a given system can be very different both in linear and nonlinear simulations, the frequency-averaged formalism should be used with caution. Despite its robustness, it is also unclear how accurately it represents tidal evolution in real (frequency-dependent) systems.
Molecular Outgassing in Centaur 29P/Schwassmann–Wachmann 1 during Its Exceptional 2021 Outburst: Coordinated Multiwavelength Observations Using nFLASH at APEX and iSHELL at the NASA-IRTF
Authors: Roth Nathan X. , Milam Stefanie N. , DiSanti Michael A. , Villanueva Geronimo L. , Faggi Sara , Bonev Boncho P. , Cordiner Martin A. , Remijan Anthony J. , Bockelée-Morvan Dominique , Biver Nicolas , Crovisier Jacques , Lis Dariusz C. , Charnley Steven B. , Jehin Emmanuel , Wirström Eva S. , McKay Adam J. 
Published: September 2023

Abstract
The extraordinary 2021 September–October outburst of Centaur 29P/Schwassmann–Wachmann 1 afforded an opportunity to test the composition of primitive Kuiper disk material at high sensitivity. We conducted nearly simultaneous multiwavelength spectroscopic observations of 29P/Schwassmann–Wachmann 1 using iSHELL at the NASA Infrared Telescope Facility (IRTF) and nFLASH at the Atacama Pathfinder EXperiment (APEX) on 2021 October 6, with follow-up APEX/nFLASH observations on 2021 October 7 and 2022 April 3. This coordinated campaign between near-infrared and radio wavelengths enabled us to sample molecular emission from a wealth of coma molecules and to perform measurements that cannot be accomplished at either wavelength alone. We securely detected CO emission on all dates with both facilities, including velocity-resolved spectra of the CO (J = 2–1) transition with APEX/nFLASH and multiple CO (v = 1–0) rovibrational transitions with IRTF/iSHELL. We report rotational temperatures, coma kinematics, and production rates for CO and stringent (3σ) upper limits on abundance ratios relative to CO for CH4, C2H6, CH3OH, H2CO, CS, and OCS. Our upper limits for CS/CO and OCS/CO represent their first values in the literature for this Centaur. Upper limits for CH4, C2H6, CH3OH, and H2CO are the most stringent reported to date, and are most similar to values found in ultra CO-rich Oort cloud comet C/2016 R2 (PanSTARRS), which may have implications for how ices are preserved in cometary nuclei. We demonstrate the superb synergy of coordinated radio and near-infrared measurements, and advocate for future small-body studies that jointly leverage the capabilities of each wavelength.
Earth as a Transiting Exoplanet: A Validation of Transmission Spectroscopy and Atmospheric Retrieval Methodologies for Terrestrial Exoplanets
Authors: Lustig-Yaeger Jacob , Meadows Victoria S. , Crisp David , Line Michael R. , Robinson Tyler D. 
Published: September 2023

Abstract
The James Webb Space Telescope (JWST) will enable the search for and characterization of terrestrial exoplanet atmospheres in the habitable zone via transmission spectroscopy. However, relatively little work has been done to use solar system data, where ground truth is known, to validate spectroscopic retrieval codes intended for exoplanet studies, particularly in the limit of high resolution and high signal-to-noise ratio (S/N). In this work, we perform such a validation by analyzing a high-S/N empirical transmission spectrum of Earth using a new terrestrial exoplanet atmospheric retrieval model with heritage in solar system remote sensing and gaseous exoplanet retrievals. We fit the Earth’s 2–14 μm transmission spectrum in low resolution (R = 250 at 5 μm) and high resolution (R = 100,000 at 5 μm) under a variety of assumptions about the 1D vertical atmospheric structure. In the limit of noiseless transmission spectra, we find excellent agreement between model and data (deviations <10%) that enable the robust detection of H2O, CO2, O3, CH4, N2, N2O, NO2, HNO3, CFC-11, and CFC-12 thereby providing compelling support for the detection of habitability, biosignature, and technosignature gases in the atmosphere of the planet using an exoplanet-analog transmission spectrum. Our retrievals at high spectral resolution show a marked sensitivity to the thermal structure of the atmosphere, trace gas abundances, density-dependent effects, such as collision-induced absorption and refraction, and even hint at 3D spatial effects. However, we used synthetic observations of TRAPPIST-1e to verify that the use of simple 1D vertically homogeneous atmospheric models will likely suffice for JWST observations of terrestrial exoplanets transiting M dwarfs.
L’apprentissage du management en entreprise avec un MOOC : l’importance du profil managérial dans la définition des attentes
Authors: Cascioli Fiammetta , Dejoux Cécile 
Published: September 2023

Cette étude mobilise une posture socio-constructiviste qui met en évidence les différentes interactions entre le MOOC et l’apprenant. Dans ce contexte, l’apprenant est considéré comme un organisme qui crée sa propre signification à travers les échanges qu’il a avec son environnement. Les travaux de recherche de Cascioli (2020) ont montré que les apprenants utilisent leurs formes de représentations pour agir de manière symbolique sur le monde conceptuel, en générant ainsi de nouvelles. Le parcours MOOC est donc considéré comme un outil numérique qui permet d’optimiser et d’élargir le processus d’apprentissage en termes de traitement, analyse et problématisation de l’information ainsi que de création de nouvelles représentations (Cox, 2013). Deux questions sont posées dans cette publication : Quelles sont les attentes d’apprentissage des apprenants qui suivent un MOOC ? Peut-on les catégoriser en fonction du profil managérial de l’apprenant ? Un traitement statistique sur 3 760 observations en relation avec le MOOC managérial le plus suivi de France, le MOOCLead de Cécile Dejoux au CNAM, permet par un cluster two steps d’identifier trois catégories d’apprenants : les « les novices », managers débutants, « les éveillés », managers intermédiaires, et « les avertis », managers confirmés. Chacune de ces catégorie fait état d’attentes distinctes, allant d’un apprentissage général des compétences numériques du manager de demain, à un approfondissement, voir, à une mise en perspective.
Going Virtual: Transitioning an Older Adult Community Health Clinical Course to Online During COVID-19
Authors: Perry Julie , Panepinto Robingale , Powers S. Cole , Flynn Heather 
Published: September 2023

Background:
Nursing students in a community health course implemented a quality improvement project with active older adults (AOA). This article describes a process for transitioning an in-person community health quality improvement (QI) project to online.

Method:
To communicate with AOA, students created a blog, “Healthy Living From Home,” that enabled communication among the AOA, partner organizations staff, and students. A quick response code was created that linked to the 6-week program. At the end of the 6 weeks, participants were asked to complete a survey.

Results:
Data collected from the QI project website tracked more than 1,000 visits to the blog. Participants rated project enjoyment, helpfulness, and educational content as 4.5 on a 5-point Likert scale.

Conclusion:

Using a multifocal online format to engage with AOA was successful and can continue to be used in the future.

[
J Nurs Educ
. 2024;63(5):332–334.]
The right place. Finding locations for the co-creation of temporary affordable housing through the Solidary Mobile Housing Pilot Project
Authors: De Smet Aurelie , Pak Burak , Schoonjans Yves , Bruyneel Geraldine 
Published: September 2023

Ces dernières années, nombre de villes ont commencé à expérimenter l’usage temporaire d’« espaces en attente » comme moyen d’améliorer la ville. Diverses initiatives ponctuelles ont vu le jour. Certaines organisations de la société civile y voient une occasion de faire face à la nécessité urgente de disposer de logements à prix modéré plus nombreux et de meilleure qualité. Mais comment cela se passe-t-il en pratique ? Le présent article décrit et évalue le processus de recherche de lieux mis au point pour le projet pilote Solidary Mobile Housing ; celui-ci s’inscrit dans le cadre d’un projet de recherche-action participative en cours visant à cocréer avec les sans-abri des logements temporaires qui leur soient destinés dans les espaces urbains en attente. À partir de cette expérience et d’échanges de connaissances avec des spécialistes de premier plan et des acteurs de terrain, il s’agit d’examiner les possibilités et les limites de l’utilisation d’espaces inoccupés ou sous-exploités pour apporter une réponse immédiate (bien que partielle et à court terme) à la crise actuelle en matière de logements abordables en assurant la mise à disposition de logements temporaires, pour les personnes vulnérables et avec leur concours, dans la Région de Bruxelles-Capitale.