bluuebunny/crossref_metadata_2025_split huggingface dataset:
The role of drag and gravity on dust concentration in a gravitationally unstable disc
Authors: Rowther Sahl , Nealon Rebecca , Meru Farzana , Wurster James , Aly Hossam , Alexander Richard , Rice Ken , Booth Richard A 
Published: January 2024

ABSTRACT
We carry out three-dimensional smoothed particle hydrodynamics simulations to study the role of gravitational and drag forces on the concentration of large dust grains (St &gt; 1) in the spiral arms of gravitationally unstable protoplanetary discs, and the resulting implications for planet formation. We find that both drag and gravity play an important role in the evolution of large dust grains. If we include both, grains that would otherwise be partially decoupled will become well coupled and trace the spirals. For the dust grains most influenced by drag (with Stokes numbers near unity), the dust disc quickly becomes gravitationally unstable and rapidly forms clumps with masses between 0.15–6M⊕. A large fraction of clumps are below the threshold where runaway gas accretion can occur. However, if dust self-gravity is neglected, the dust is unable to form clumps, despite still becoming trapped in the gas spirals. When large dust grains are unable to feel either gas gravity or drag, the dust is unable to trace the gas spirals. Hence, full physics is needed to properly simulate dust in gravitationally unstable discs. Dust trapping of large grains in spiral arms of discs stable to gas fragmentation could explain planet formation in very young discs by a population of planetesimals formed due to the combined roles of drag and gravity in the earliest stages of a disc’s evolution. Furthermore, it highlights that gravitationally unstable discs are not just important for forming gas giants quickly, it can also rapidly form Earth mass bodies.
Oscillating shocks in the transonic viscous, variable Γ accretion flows around black holes
Authors: Debnath Sanjit , Chattopadhyay Indranil , Joshi Raj Kishor 
Published: January 2024

ABSTRACT
We investigate the time evolution of the transonic-viscous accretion flow around a non-rotating black hole. The input parameters used for the simulation are obtained from semi-analytical solutions. This code is based on the total variation diminishing routine and correctly handles the angular momentum transport due to viscosity. The thermodynamic properties of the flow are described by a variable adiabatic index equation of state. We regenerate the inviscid and viscous steady-state solutions, including shocks, using the simulation code and compare them with the semi-analytical solutions. The angular momentum piles up across a shock due to shock-jump conditions and viscous transport of angular momentum. This will push the shock-front outward and can result in shock oscillation or a complete destabilization of shock. We study how shocks behave in the presence of viscosity. As the viscosity parameter (α) crosses a critical value, the previously steady shock becomes time-dependent, eventually leading to oscillations. The value of this critical viscosity depends on the injection angular momentum (λou) and the specific energy (ϵ). We estimated the posteriori bremsstrahlung and synchrotron cooling, and the net radiative output also oscillates with the frequency of the shock. We also study the variation of frequency, amplitude, and mean position of oscillation with α. Considering a black hole with a mass of 10 M⊙, we observed that the power spectrum exhibits a prominent peak at the fundamental frequency of a few to about tens of Hz, accompanied by multiple harmonics. This characteristic is frequently observed in numerous accreting black hole candidates.
Reverse shock emission in an off-axis top-hat jet model for gamma-ray bursts
Authors: Pang Sen-Lin , Dai Zi-Gao 
Published: January 2024

ABSTRACT
The afterglow of a gamma-ray burst (GRB) has been widely argued to arise from the interaction of a relativistic outflow with its ambient medium. During such an interaction, a pair of shocks are generated: a forward shock that propagates into the medium and a reverse shock that propagates into the outflow. Extensive studies have been conducted on the emission from the forward shock viewed off-axis. Furthermore, the observation of a reverse shock in an on-axis short GRB suggests that the reverse shock can produce an electromagnetic counterpart to a gravitational wave-detected merger. In this paper, we investigate the contribution of the reverse shock to the afterglow from a top-hat jet viewed off-axis, and apply our model to some short GRBs previously modelled by an off-axis emission. We employ the Markov Chain Monte Carlo (MCMC) method to get the model parameters (i.e. the jet’s half-opeaning angle θj, the viewing angle θobs, the initial Lorentz factor Γ0, and the isotropic energy Eiso). Our model successfully reproduces off-axis afterglow emission without a structured jet. In addition, our calculations suggest that the reverse shock may produce a prominent feature in an early afterglow, which can be potentially observed in an orphan optical afterglow.
Potential biases and prospects for the Hubble constant estimation via electromagnetic and gravitational-wave joint analyses
Authors: Gianfagna Giulia , Piro Luigi , Pannarale Francesco , Van Eerten Hendrik , Ricci Fulvio , Ryan Geoffrey 
Published: January 2024

ABSTRACT
GW170817 is a binary neutron star merger that exhibited a gravitational wave (GW) and a gamma-ray burst, followed by an afterglow. In this work, we estimate the Hubble constant (H0) using broad-band afterglow emission and relativistic jet motion from the Very Long Baseline Interferometry and HST images of GW170817. Compared to previous attempts, we combine these messengers with GW in a simultaneous Bayesian fit. We probe the H0 measurement robustness depending on the data set used, the assumed jet model, the possible presence of a late time flux excess. Using the sole GW leads to a 20 per cent error ($77^{+21}_{-10}$ $\rm km\, s^{-1}\, Mpc^{-1}$, medians, 16th–84th percentiles), because of the degeneracy between viewing angle (θv) and luminosity distance (dL). The latter is reduced by the inclusion in the fit of the afterglow light curve, leading to $H_0=96^{+13}_{-10}$ $\rm km\, s^{-1}\, Mpc^{-1}$, a large value, caused by the fit preference for high viewing angles due to the possible presence of a late-time excess in the afterglow flux. Accounting for the latter by including a constant flux component at late times brings $H_0=78.5^{+7.9}_{-6.4}$$\rm km\, s^{-1}\, Mpc^{-1}$. Adding the centroid motion in the analysis efficiently breaks, the dL − θv degeneracy and overcome the late-time deviations, giving $H_0 = 69.0^{+4.4}_{-4.3}$ $\rm km\, s^{-1}\, Mpc^{-1}$ (in agreement with Planck and SH0ES measurements) and $\theta _{\rm v} = 18.2^{+1.2}_{-1.5}$°. This is valid regardless of the jet structure assumption. Our simulations show that for next GW runs radio observations are expected to provide at most few other similar events.
Shock-driven synchrotron radio emission from the 2021 outburst of RS Ophiuchi
Authors: A J Nayana , Anupama G C , Roy Nirupam , Banerjee Dipankar P K , Singh Kulinder Pal , Sonith L S , Kamath U S 
Published: January 2024

ABSTRACT
We present low-frequency radio observations of the Galactic symbiotic recurrent nova RS Ophiuchi during its 2021 outburst. The observations were carried out with the upgraded Giant Metrewave Radio Telescope spanning a frequency range of 0.15–1.4 GHz during 23–287 d post the outburst. The average value of the optically thin spectral index is α ∼ −0.4 (Fν ∝ να), indicating a non-thermal origin of the radio emission at the observed frequencies. The radio light curves are best represented by shock-driven synchrotron emission, initially absorbed by a clumpy ionized circumbinary medium. We estimate the mass-loss rate of the red giant companion star to be $\dot{M} \sim$ 7.5 × 10−8 M⊙ yr−1 for an assumed stellar wind velocity of 20 km s−1. The 0.15–1.4 GHz radio light curves of the 2021 outburst are systematically brighter than those of the 2006 outburst. Considering similar shock properties between the two outbursts, this is indicative of a relatively higher particle number density in the synchrotron emitting plasma in the current outburst.
TREVR2: illuminating fast N log2N radiative transfer
Authors: Wadsley James W , Baumschlager Bernhard , Shen Sijing 
Published: January 2024

ABSTRACT
We present trevr2 (Tree-based REVerse Ray Tracing 2), a fast, general algorithm for computing the radiation field, suitable for both particle and mesh codes. It is designed to self-consistently evolve chemistry for zoomed-in astrophysical simulations, such as cosmological galaxies with both internal sources and prescribed background radiation, rather than large periodic volumes. Light is propagated until absorbed, with no imposed speed limit other than those due to opacity changes (e.g. ionization fronts). trevr2 searches outward from receiving gas in discrete directions set by the healpix algorithm (unlike its slower predecessor trevr), accumulating optical depth and adding the flux due to sources combined into progressively larger tree cells with distance. We demonstrate Nactivelog2N execution time with absorption and many sources. This allows multiband radiative transfer costs comparable to tree-based gravity and hydrodynamics, and the usual speed-up when active particles evolve on individual time-steps. Sources embedded in non-homogeneous absorbing material introduce systematic errors. We introduce transmission averaging instead of absorption averaging which dramatically reduces these systematic effects. We outline other ways to address systematics including an explicit complex source model. We demonstrate the overall performance of the method via a set of astrophysical test problems.
MHz to TeV expectations from scotogenic WIMP dark matter
Authors: Eisenberger Laura , Siegert Thomas , Mannheim Karl , Porod Werner 
Published: January 2024

ABSTRACT
The indirect search for dark matter is typically restricted to individual photon bands and instruments. In the context of multiwavelength observations, finding a weak signal in large foreground and background at only one wavelength band is hampered by systematic uncertainties dominating the signal strength. Dark matter particle annihilation is producing Standard Model particles of which the prompt photon emission is searched for in many studies. However, also the secondary emission of charged particles from dark matter annihilation in the TeV range results in comparable or even stronger fluxes in the GHz–GeV range. In this study, we calculate the prompt and secondary emission of a scotogenic weakly interacting massive particle (WIMP) with a mass of 1 TeV in 27 dwarf galaxies of the Milky Way. For the secondary emission, we include inverse Compton scattering, bremsstrahlung, and synchrotron radiation, which results in a ‘triple hump’ structure characteristic for only dark matter and no other astrophysical source. In order to determine the best candidates for multi-instrument analyses, we estimate the diffuse emission component of the Milky Way itself, including its own dark matter halo from the same scotogenic WIMP model. We find signal-to-background ratios of individual sources on the order of 10−3 to 10−2 across X-ray to γ-ray assuming J factors for the cold dark matter distribution inferred from observations and no additional boosting due to small-scale clumping. We argue that a joint multiwavelength analysis of all nearby galaxies and the extension towards the cosmic gamma-ray background is required to disentangle possible dark matter signals from astrophysical background and foreground.
Tungsten in barium stars
Authors: Roriz M P , Lugaro M , Junqueira S , Sneden C , Drake N A , Pereira C B 
Published: January 2024

ABSTRACT
Classical barium stars are red giants that receive from their evolved binary companions material exposed to the slow neutron-capture nucleosynthesis, i.e. the s-process. Such a mechanism is expected to have taken place in the interiors of Thermally-Pulsing Asymptotic Giant Branch (TP-AGB) stars. As post-interacting binaries, barium stars figure as powerful tracers of the s-process nucleosynthesis, evolution of binary systems, and mechanisms of mass transfer. The present study is the fourth in a series of high-resolution spectroscopic analyses on a sample of 180 barium stars, for which we report tungsten (W, Z = 74) abundances. The abundances were derived from synthetic spectrum computations of the W i absorption features at 4843.8 and 5224.7 Å. We were able to extract abundances for 94 stars; the measured [W/Fe] ratios range from ∼0.0 to 2.0 dex, increasing with decreasing metallicity. We noticed that in the plane [W/Fe] versus [s/Fe], barium stars follow the same trend observed in post-AGB stars. The observational data were also compared with predictions of the FRUITY and Monash AGB nucleosynthesis models. These expect values between −0.20 and +0.10 dex for the [W/hs] ratios, whereas a larger spread is observed in the program stars, with [W/hs] ranging from −0.40 to +0.60 dex. The stars with high [W/hs] ratios may represent evidence for the operation of the intermediate neuron-capture process at metallicities close to solar.
Torque-dependent orbital modulation of X-ray pulsar Cen X-3
Authors: Liao Zhenxuan , Liu Jiren 
Published: January 2024

ABSTRACT
Cen X-3 shows alternate spin-up/spin-down episodes lasting for tens of days. We study the orbital profiles and spectra of Cen X-3 during these spin-up/spin-down intervals, using long-term data monitored by Fermi/Gamma-ray Burst Monitor (GBM), Swift/Burst Alert Telescope (BAT), and Monitor of All-sky X-ray Image (MAXI)/Gas Slit Camera (GSC). In spin-up intervals, its orbital profile in 2–10 keV is symmetrically peaked around orbital phase 0.42, while in spin-down intervals of similar fluxes and similar magnitudes of spin change rate, its profile reaches a peak around orbital phase 0.22 and then declines gradually. Such a distinct orbital difference between spin-up and spin-down states of similar flux is hard to explain in the standard disc model and indicates that its torque reversals are related to processes on the orbital scale. The durations of continuous spin-up/spin-down trend (tens of days) also point to a superorbital variation. One possible scenario is the irradiation-driven warping disc instability, which may produce a flipped inner disc for tens of days.
Genetically Encoded Lizard Color Divergence for Camouflage and Thermoregulation
Authors: Sun Bao-Jun , Li Wei-Ming , Lv Peng , Wen Guan-Nan , Wu Dan-Yang , Tao Shi-Ang , Liao Ming-Ling , Yu Chang-Qing , Jiang Zhong-Wen , Wang Yang , Xie Hong-Xin , Wang Xi-Feng , Chen Zhi-Qiang , Liu Feng , Du Wei-Guo 
Published: January 2024

Abstract
Local adaptation is critical in speciation and evolution, yet comprehensive studies on proximate and ultimate causes of local adaptation are generally scarce. Here, we integrated field ecological experiments, genome sequencing, and genetic verification to demonstrate both driving forces and molecular mechanisms governing local adaptation of body coloration in a lizard from the Qinghai-Tibet Plateau. We found dark lizards from the cold meadow population had lower spectrum reflectance but higher melanin contents than light counterparts from the warm dune population. Additionally, the colorations of both dark and light lizards facilitated the camouflage and thermoregulation in their respective microhabitat simultaneously. More importantly, by genome resequencing analysis, we detected a novel mutation in Tyrp1 that underpinned this color adaptation. The allele frequencies at the site of SNP 459# in the gene of Tyrp1 are 22.22% G/C and 77.78% C/C in dark lizards and 100% G/G in light lizards. Model-predicted structure and catalytic activity showed that this mutation increased structure flexibility and catalytic activity in enzyme TYRP1, and thereby facilitated the generation of eumelanin in dark lizards. The function of the mutation in Tyrp1 was further verified by more melanin contents and darker coloration detected in the zebrafish injected with the genotype of Tyrp1 from dark lizards. Therefore, our study demonstrates that a novel mutation of a major melanin-generating gene underpins skin color variation co-selected by camouflage and thermoregulation in a lizard. The resulting strong selection may reinforce adaptive genetic divergence and enable the persistence of adjacent populations with distinct body coloration.
Gut flora metagenomic analysis coupled with metabolic and deep immune profiling in chronic kidney disease
Authors: Wu I-Wen , Chang Lun-Ching , Wu Yi-Lun , Yang Huang-Yu , Twu Yuh-Ching , Tsai Po-Yu , Paulus Skyler , Resnick Rhian , Chung Wen-Hung , Yang Chih-Wei , Hsieh Wen-Ping , Su Shih-Chi 
Published: January 2024

ABSTRACT

Background
Perturbation of gut microbiota has been linked to chronic kidney disease (CKD), which was correlated with a sophisticated milieu of metabolic and immune dysregulation.

Methods
To clarify the underlying host–microbe interaction in CKD, we performed multi-omics measurements, including systems-level gut microbiome, targeted serum metabolome and deep immunotyping, in a cohort of patients and non-CKD controls.

Results
Our analyses on functional profiles of the gut microbiome showed a decrease in the diversity and abundance of carbohydrate-active enzyme (CAZyme) genes but an increase in the abundance of antibiotic resistance, nitrogen cycling enzyme and virulence factor genes in CKD. Moreover, models generated using measurements of serum metabolites (amino acids, bile acids and short-chain fatty acids) or immunotypes were predictive of renal impairment but less so than many of the functional profiles derived from gut microbiota, with the CAZyme genes being the top-performing model to accurately predict the early stage of diseases. In addition, co-occurrence analyses revealed coordinated host–microbe relationships in CKD. Specifically, the highest fractions of significant correlations were identified with circulating metabolites by several taxonomic and functional profiles of gut microbiome, while immunotype features were moderately associated with the abundance of microbiome-encoded metabolic pathways and serum levels of amino acids (e.g. B cell cluster tryptophan and B cell cluster tryptophan metabolism).

Conclusion
Overall, our multi-omics integration revealed several signatures of systems-level gut microbiome in robust associations with host–microbe co-metabolites and renal function, which may have aetiological and diagnostic implications in CKD.
Hyperkalaemia-related reduction of RAASi treatment associates with more subsequent inpatient care
Authors: Svensson Maria K , Murohara Toyoaki , Lesén Eva , Arnold Matthew , Cars Thomas , Järbrink Krister , Chen Gengshi , Morita Naru , Venkatesan Sudhir , Kanda Eiichiro 
Published: January 2024

ABSTRACT

Background
Hyperkalaemia is a barrier to achieving optimal, guideline-directed treatment with renin–angiotensin–aldosterone system inhibitors (RAASis) in patients with chronic kidney disease (CKD) and/or heart failure (HF). This study describes the association between hyperkalaemia-related RAASi treatment reduction and the number of hospitalized days in patients with CKD and/or HF in Sweden and Japan.

Methods
Using data from health registers and hospital medical records, patients with CKD and/or HF currently receiving RAASis who experienced an index hyperkalaemia episode were identified and categorized as having maintained or reduced RAASi treatment post-index; propensity score matching (1:1) was applied to balance the groups in terms of baseline characteristics. Changes in the number of all-cause, CKD- and HF-related hospitalized days per patient-year during 6 months pre- versus post-index and the number of days alive and out of hospital (DAOH) during 6 months post-index were described.

Results
Overall, 20 824 and 7789 patients were included from Sweden and Japan, respectively, 42% and 38% of whom reduced their RAASi treatment after the index hyperkalaemia episode. During the 6 months post-index, all-cause hospitalization increased by 18.2 days [95% confidence interval (CI) 17.0–19.2] per person-year in Sweden and 17.9 days (95% CI 17.4–18.5) per person-year in Japan among patients with reduced RAASi treatment compared with increases of 9.4 days (95% CI 8.6–10.4) and 8.5 days (95% CI 8.0–9.0) per person-year, respectively, among patients with maintained RAASi treatment. The mean DAOH was 121.5 [standard deviation (SD) 75.0] in Sweden and 141.7 (SD 54.5) in Japan among patients with reduced RAASi treatment compared with 154.0 (SD 51.3) and 157.5 (SD 31.6), respectively, among patients with maintained RAASi treatment.

Conclusion
Patients whose RAASi treatment was reduced after a hyperkalaemia episode had more hospitalized days and fewer DAOH compared with patients whose RAASi treatment was maintained.
Fluorescein-stained confocal laser endomicroscopy versus conventional frozen section for intraoperative histopathological assessment of intracranial tumors
Authors: Wagner Arthur , Brielmaier Maria Charlotte , Kampf Charlotte , Baumgart Lea , Aftahy Amir Kaywan , Meyer Hanno S , Kehl Victoria , Höhne Julius , Schebesch Karl-Michael , Schmidt Nils O , Zoubaa Saida , Riemenschneider Markus J , Ratliff Miriam , Enders Frederik , von Deimling Andreas , Liesche-Starnecker Friederike , Delbridge Claire , Schlegel Juergen , Meyer Bernhard , Gempt Jens 
Published: January 2024

Abstract

Background
The aim of this clinical trial was to compare Fluorescein-stained intraoperative confocal laser endomicroscopy (CLE) of intracranial lesions and evaluation by a neuropathologist with routine intraoperative frozen section (FS) assessment by neuropathology.

Methods
In this phase II noninferiority, prospective, multicenter, nonrandomized, off-label clinical trial (EudraCT: 2019-004512-58), patients above the age of 18 years with any intracranial lesion scheduled for elective resection were included. The diagnostic accuracies of both CLE and FS referenced with the final histopathological diagnosis were statistically compared in a noninferiority analysis, representing the primary endpoint. Secondary endpoints included the safety of the technique and time expedited for CLE and FS.

Results
A total of 210 patients were included by 3 participating sites between November 2020 and June 2022. Most common entities were high-grade gliomas (37.9%), metastases (24.1%), and meningiomas (22.7%). A total of 6 serious adverse events in 4 (2%) patients were recorded. For the primary endpoint, the diagnostic accuracy for CLE was inferior with 0.87 versus 0.91 for FS, resulting in a difference of 0.04 (95% confidence interval −0.10; 0.02; P = .367). The median time expedited until intraoperative diagnosis was 3 minutes for CLE and 27 minutes for FS, with a mean difference of 27.5 minutes (standard deviation 14.5; P &lt; .001).

Conclusions
CLE allowed for a safe and time-effective intraoperative histological diagnosis with a diagnostic accuracy of 87% across all intracranial entities included. The technique achieved histological assessments in real time with a 10-fold reduction of processing time compared to FS, which may invariably impact surgical strategy on the fly.