bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rapid grain growth in post-AGB disc systems from far-infrared and sub-millimetre photometry
Authors: Scicluna P , Kemper F , Trejo A , Marshall J P , Ertel S , Hillen M 
Published: February 2020

ABSTRACT
The time-scales on which astronomical dust grows remain poorly understood, with important consequences for our understanding of processes like circumstellar disc evolution and planet formation. A number of post-asymptotic giant branch (AGB) stars are found to host optically thick, dust- and gas-rich circumstellar discs in Keplerian orbits. These discs exhibit evidence of dust evolution, similar to protoplanetary discs; however, since post-AGB discs have substantially shorter lifetimes than protoplanetary discs, they may provide new insights on the grain-growth process. We examine a sample of post-AGB stars with discs to determine the far-infrared and sub-millimetre spectral index by homogeneously fitting a sample of data from Herschel, the Submillimeter Array (SMA), and the literature. We find that grain growth to at least hundreds of micrometres is ubiquitous in these systems, and that the distribution of spectral indices is more similar to that of protoplanetary discs than debris discs. No correlation is found with the mid-infrared colours of the discs, implying that grain growth occurs independently of the disc structure in post-AGB discs. We infer that grain growth to ∼millimetre sizes must occur on time-scales &lt;&lt;105 yr, perhaps by orders of magnitude, as the lifetimes of these discs are expected to be ≲105 yr and all objects have converged to the same state. This growth time-scale is short compared to the results of models for protoplanetary discs including fragmentation and may provide new constraints on the physics of grain growth.
Hot Jupiter atmospheric flows at high resolution
Authors: Menou Kristen 
Published: February 2020

ABSTRACT
Global circulation models (GCMs) of atmospheric flows are now routinely used to interpret observational data on hot Jupiters. Localized ‘equatorial β-plane’ simulations have revealed that a barotropic (horizontal shear) instability of the equatorial jet appears at horizontal resolutions beyond those typically achieved in global models; this instability could limit wind speeds and lead to increased atmospheric variability. To address this possibility, we adapt the computationally efficient, pseudo-spectral PlaSim GCM, originally designed for Earth studies, to model hot Jupiter atmospheric flows and validate it on a reference benchmark. We then present high-resolution global models of HD209458b, with horizontal resolutions of T85 (128×256) and T127 (192×384). The barotropic instability phenomenology found in β-plane simulations is not reproduced in these global models, despite comparably high meridional resolutions. Nevertheless, high-resolution models do exhibit additional flow variability on long time-scales (of the order of 100 planet days or more), which is absent from the lower resolution models. It manifests as a breakdown of the north–south symmetry of the equatorial wind. By post-processing the atmospheric flows at various resolutions (assuming a cloud-free situation), we show that the stronger flow variability achieved at high resolution does not translate into noticeably stronger dayside infrared flux variability. More generally, our results suggest that high horizontal resolutions are not required to capture the key features of hot Jupiter atmospheric flows.
Acoustic wave generation in collapsing massive stars with convective shells
Authors: Abdikamalov Ernazar , Foglizzo Thierry 
Published: February 2020

ABSTRACT
The convection that takes place in the innermost shells of massive stars plays an important role in the formation of core-collapse supernova explosions. Upon encountering the supernova shock, additional turbulence is generated, amplifying the explosion. In this work, we study how the convective perturbations evolve during the stellar collapse. Our main aim is to establish their physical properties right before they reach the supernova shock. To this end, we solve the linearized hydrodynamics equations perturbed on a stationary background flow. The latter is approximated by the spherical transonic Bondi accretion, while the convective perturbations are modelled as a combination of entropy and vorticity waves. We follow their evolution from large radii, where convective shells are initially located, down to small radii, where they are expected to encounter the accretion shock above the proto-neutron star. Considering typical vorticity perturbations with a Mach number ∼0.1 and entropy perturbations with magnitude ∼0.05kb/baryon, we find that the advection of these perturbations down to the shock generates acoustic waves with a relative amplitude $\delta {\rm p}/\gamma {\rm p} \lesssim 10{{\ \rm per\ cent}}$, in agreement with published numerical simulations. The velocity perturbations consist of contributions from acoustic and vorticity waves with values reaching ${\sim}10{{\ \rm per\ cent}}$ of the sound speed ahead of the shock. The perturbation amplitudes decrease with increasing ℓ and initial radii of the convective shells.
Spectropolarimetric analysis of prompt emission of GRB 160325A: jet with evolving environment of internal shocks
Authors: Sharma Vidushi , Iyyani Shabnam , Bhattacharya Dipankar , Chattopadhyay Tanmoy , Vadawale Santosh V , Bhalerao Varun B 
Published: February 2020

ABSTRACTGRB 160325A is the only bright burst detected by AstroSat CZT Imager in its primary field of view to date. In this work, we present the spectral and polarimetric analysis of the prompt emission of the burst using AstroSat, Fermi, and Niel Gehrels Swift observations. The prompt emission consists of two distinct emission episodes separated by a few seconds of quiescent/ mild activity period. The first emission episode shows a thermal component as well as a low polarization fraction of $PF \lt 37\, {{\ \rm per\ cent}}$ at $1.5\, \sigma$ confidence level. On the other hand, the second emission episode shows a non-thermal spectrum and is found to be highly polarized with $PF \gt 43\, {{\ \rm per\ cent}}$ at 1.5σ confidence level. We also study the afterglow properties of the jet using Swift/XRT data. The observed jet break suggests that the jet is pointed towards the observer and has an opening angle of 1.2° for an assumed redshift, z = 2. With composite modelling of polarization, spectrum of the prompt emission, and the afterglow, we infer that the first episode of emission originates from the photosphere with localized dissipation happening below it, and the second from the optically thin region above the photosphere. The photospheric emission is generated mainly by inverse Compton scattering, whereas the emission in the optically thin region is produced by the synchrotron process. The low radiation efficiency of the burst suggests that the outflow remains baryonic dominated throughout the burst duration with only a subdominant Poynting flux component, and the kinetic energy of the jet is likely dissipated via internal shocks which evolves from an optically thick to optically thin environment within the jet.
Dynamical evolution of fractal structures in star-forming regions
Authors: Daffern-Powell Emma C , Parker Richard J 
Published: February 2020

ABSTRACT
The $\mathcal {Q}$-parameter is used extensively to quantify the spatial distributions of stars and gas in star-forming regions as well as older clusters and associations. It quantifies the amount of structure using the ratio of the average length of the minimum spanning tree, $\bar{m}$, to the average length within the complete graph, $\bar{s}$. The interpretation of the $\mathcal {Q}$-parameter often relies on comparing observed values of $\mathcal {Q}$, $\bar{m}$, and $\bar{s}$ to idealized synthetic geometries, where there is little or no match between the observed star-forming regions and the synthetic regions. We measure $\mathcal {Q}$, $\bar{m}$, and $\bar{s}$ over 10 Myr in N-body simulations, which are compared to IC 348, NGC 1333, and the ONC. For each star-forming region, we set up simulations that approximate their initial conditions for a combination of different virial ratios and fractal dimensions. We find that the dynamical evolution of idealized fractal geometries can account for the observed $\mathcal {Q}$, $\bar{m}$, and $\bar{s}$ values in nearby star-forming regions. In general, an initially fractal star-forming region will tend to evolve to become more smooth and centrally concentrated. However, we show that different initial conditions, as well as where the edge of the region is defined, can cause significant differences in the path that a star-forming region takes across the $\bar{m}{-}\bar{s}$ plot as it evolves. We caution that the observed $\mathcal {Q}$-parameter should not be directly compared to idealized geometries. Instead, it should be used to determine the degree to which a star-forming region is either spatially substructured or smooth and centrally concentrated.
The role of the sonic scale in the growth of magnetic field in compressible turbulence
Authors: Fouxon Itzhak , Mond Michael 
Published: February 2020

ABSTRACT
We study the growth of small fluctuations of magnetic field in supersonic turbulence, the small-scale dynamo. The growth is due to the smallest and fastest turbulent eddies above the resistive scale. We observe that for supersonic turbulence these eddies are localized below the sonic scale ls, defined as the scale where the typical velocity of the turbulent eddies equals the speed of sound, and are therefore effectively incompressible. All previous studies have ignored the existence of the sonic scale and consequently treated the entire inertial range as made up of compressible eddies. However, at large Mach numbers ls is much smaller than the integral scale of the turbulence so the fastest growing mode of the magnetic field belongs to small-scale incompressible turbulence. We determine this mode and the associated growth rate numerically with the aid of a white noise in time model of turbulence whose approximate validity for the description of the Navier–Stokes turbulence is explained. For that purpose, we introduce a new non-dimensional number Rsm that we name the magnetosonic Reynolds number that describes the division of the magnetic field amplification range between small-scale incompressible eddies and large-scale supersonic ones. We show that indeed, as Rsm grows (which means that the incompressible eddies occupy a larger portion of the magnetic field amplification range) the growth rate of the fastest growing mode increases, while the spatial distribution of the growing magnetic field shifts to smaller scales. Our result implies the existence of small-scale dynamo for compressible homogeneous turbulence.
Evidence for radio and X-ray auroral emissions from the magnetic B-type star ρ Oph A
Authors: Leto P , Trigilio C , Leone F , Pillitteri I , Buemi C S , Fossati L , Cavallaro F , Oskinova L M , Ignace R , Krtička J , Umana G , Catanzaro G , Ingallinera A , Bufano F , Agliozzo C , Phillips N M , Cerrigone L , Riggi S , Loru S , Munari M , Gangi M , Giarrusso M , Robrade J 
Published: February 2020

Abstract
We present new ATCA multiwavelength radio measurements (range 2.1–21.2 GHz) of the early-type magnetic star ρ Oph A, performed in 2019 March during three different observing sessions. These new ATCA observations evidence a clear rotational modulation of the stellar radio emission and the detection of coherent auroral radio emission from ρ Oph A at 2.1 GHz. We collected high-resolution optical spectra of ρ Oph A acquired by several instruments over a time span of about 10 yr. We also report new magnetic field measurements of ρ Oph A that, together with the radio light curves and the temporal variation of the equivalent width of the He i line (λ = 5015 Å), were used to constrain the rotation period and the stellar magnetic field geometry. The above results have been used to model the stellar radio emission, modelling that allowed us to constrain the physical condition of ρ Oph A’s magnetosphere. Past XMM–Newton measurements showed periodic X-ray pulses from ρ Oph A. We correlate the X-ray light curve with the magnetic field geometry of ρ Oph A. The already published XMM–Newton data have been re-analysed showing that the X-ray spectra of ρ Oph A are compatible with the presence of a non-thermal X-ray component. We discuss a scenario where the emission phenomena occurring at the extremes of the electromagnetic spectrum, radio and X-ray, are directly induced by the same plasma process. We interpret the observed X-ray and radio features of ρ Oph A as having an auroral origin.
Smoking and Quitting Behavior by Sexual Orientation: A Cross-Sectional Survey of Adults in England
Authors: Jackson Sarah E , Brown Jamie , Grabovac Igor , Cheeseman Hazel , Osborne Ciaran , Shahab Lion 
Published: February 2020

Abstract

Objective
To assess associations between sexual orientation and smoking and quitting behavior among adults in England.

Methods
Data were collected from 112 537 adults (≥16 years) participating in a nationally representative monthly cross-sectional survey between July 2013 and February 2019. Sexual orientation was self-reported as heterosexual, bisexual, lesbian/gay, or prefer-not-to-say. Main outcomes were smoking status, e-cigarette use, cigarettes per day, time to first cigarette, motivation to stop smoking, motives for quitting, use of cessation support, and past-year quit attempts. Associations were analyzed separately for men and women using multivariable regression models adjusted for relevant covariates.

Results
Smoking prevalence is now similar between gay (21.6%), prefer-not-to-say (20.5%) and heterosexual men (20.0%), and lesbian (18.3%) and heterosexual women (16.9%), but remains higher among bisexual men (28.2%, adjusted odds ratio [ORadj] = 1.41, 95% confidence interval [CI] = 1.11 to 1.79) and bisexual women (29.8%, ORadj = 1.64, 95% CI = 1.33 to 2.03) and lower among prefer-not-to-say women (14.5%, ORadj = 0.85, 95% CI = 0.72 to 0.99). Among smokers, bisexuals were less addicted than heterosexuals, with bisexual men smoking fewer cigarettes per day (Badj = −2.41, 95% CI = −4.06 to −0.75) and bisexual women less likely to start smoking within 30 min of waking (ORadj = 0.66, 95% CI = 0.45 to 0.95) than heterosexuals. However, motivation to stop smoking and quit attempts did not differ significantly.

Conclusions
In England, differences in smoking prevalence among people with different sexual orientations have narrowed, primarily driven by a larger decline in smoking rates among sexual minority groups than heterosexuals. Bisexual men and women remain more likely to smoke but have lower levels of addiction while being no less likely to try to quit.

Implications
This population-based study provides an up-to-date picture of smoking and quitting behavior in relation to sexual orientation among adults in England. Findings suggest that widely documented disparities in smoking prevalence have narrowed over recent years, with gay men and lesbian women no longer significantly more likely to smoke than heterosexuals, although smoking remains more common among bisexual men and women. Insights into differences in level of addiction, use of cessation support, and motives for quitting may help inform the development of targeted interventions to further reduce smoking among sexual minority groups.
Effects of Partisan Personalization in a News Portal Experiment
Authors: Bryanov Kirill , Watson Brian K , Pingree Raymond J , Santia Martina 
Published: February 2020

AbstractWhat happens when news aggregators tailor their newsfeeds to include partisan news aimed at users with a known party preference? Relying on a custom-made news portal featuring real, timely articles, this study examines the influence of partisan news sources on participant headline exposure, clicks on news stories to read, and perceptions about the portal’s ability to reliably and comprehensively provide the most important news of the day. Over a period of 12 days, participants preferring either the Republican or Democratic party were randomly assigned to newsfeeds containing increased dosages of real news articles from sources supportive of the participant’s preferred party. Results demonstrate that partisan personalization can benefit a news aggregator by increasing usage and perceptions of its quality, while potentially harming society by decreasing attention to high-quality mainstream sources.
Articular manifestations in patients with inflammatory bowel disease treated with vedolizumab
Authors: Dupré Anastasia , Collins Michael , Nocturne Gaétane , Carbonnel Franck , Mariette Xavier , Seror Raphaèle 
Published: February 2020

Abstract

Objective
Vedolizumab (VDZ) has been incriminated in the occurrence of articular manifestations in patients with inflammatory bowel diseases (IBDs). The aim of this study was to describe musculoskeletal manifestations occurring in IBD patients treated by VDZ and to identify risk factors.

Methods
In this retrospective monocentric study, we included all consecutive patients treated by VDZ for IBD in our hospital. Incident musculoskeletal manifestations occurring during VDZ treatment were analysed and characteristics of patients with and without articular inflammatory manifestations were compared.

Results
Between 2013 and 2017, 112 patients were treated with VDZ for IBD: ulcerative colitis (n = 59), Crohn’s disease (n = 49) and undetermined colitis (n = 4). Four patients (3.6%) had a history of SpA, whereas 13 (11.6%) had a history of peripheral arthralgia. Some 102 (91.1%) patients had previously received anti-TNF. After a mean (S.d.) follow-up of 11.4 (8.6) months, 32 (28.6%) patients presented 35 musculoskeletal manifestations, of which 18 were mechanical and 17 inflammatory. Among the latter, 11 had axial or peripheral SpA, 5 had early reversible arthralgia and 1 had chondrocalcinosis (n = 1). Among the 11 SpA patients, only 3 (2.6%) had inactive IBD and may be considered as paradoxical SpA. The only factor associated with occurrence of inflammatory manifestations was history of inflammatory articular manifestation [7/16 (43.8%) vs 10/80 (12.5%), P = 0.007].

Conclusion
Musculoskeletal manifestations occurred in almost 30% of IBD patients treated with VDZ, but only half of them were inflammatory. Since most of the patients previously received anti-TNF, occurrence of inflammatory articular manifestations might rather be linked to anti-TNF discontinuation than to VDZ itself.
INDOOR RADON AND THORON IN THE VICINITY OF PROPOSED URANIUM MINING SITE: A CASE STUDY AT DASARLAPALLY VILLAGE, TELANGANA STATE, INDIA
Authors: Suman G , Reddy K Vinay Kumar , Reddy M Sreenath , Reddy Ch Gopal , Reddy P Yadagiri 
Published: February 2020

Abstract
Studies are being conducted for the past few decades in and around the uranium mining sites across the globe to identify environmental nuclear radiation risk to the common public. The area near Dasarlapally village was identified for uranium exploration by the AMDER, Hyderabad. The present study was carried out to measure the indoor radon and thoron activity concentrations in the dwellings of Dasarlapally village. For this purpose different types of dwellings were chosen randomly across the village. The measured annual average concentration of radon and thoron in dwellings were found to be 141 ± 42 and 139 ± 77 Bqm−3, respectively, and the calculated annual effective inhalation dose due to radon was determined to be 3.5 mSv. Seasonal variation and diurnal variation of radon and thoron activity concentration were investigated. The variation of radon and thoron activity concentration in different types of dwellings was also studied, and the variation was found to be statistically insignificant. The uncertainty propagated in the effective inhalation dose due to thoron was discussed.
Does Greater Regulatory Burden Lead to More Corruption? Evidence Using Firm-Level Survey Data for Developing Countries
Authors: Amin Mohammad , Soh Yew Chong 
Published: February 2020

Abstract
It is sometimes thought that regulation often creates opportunities for public officials to extract bribes. If this is true, deregulation offers a simple way of combating corruption. However, empirical evidence on the corruption and regulation nexus is limited. Further, the corruption indices used are based on experts’ opinions, which may suffer from perception bias. The present paper attempts to address these shortcomings using firm-level survey data for 131 mostly developing countries on the actual experience of the firms with bribery and regulatory burden. The study examines the level of overall corruption and petty corruption. Exploiting variation in regulatory burden, both within-country and industry-level, a large positive effect of regulatory burden on corruption is found. For the baseline results, the bribery rate is higher by about 0.03 percentage points for each percentage point increase in the regulatory burden. The finding is robust to several controls and endogeneity checks.
Relationship between the Incidence of Postoperative Fistula or Dysphagia and Resection Style, Gastric Tube Formation, and Irradiation following Free Jejunal Flap Transfer
Authors: Onoda Satoshi , Kinoshita Masahito , Ariyoshi Yukino 
Published: February 2020

Background:
The purpose of this study was to examine the relationship between the incidence of dysphagia or fistula formation in an anastomotic region and factors such as extent of resection, gastric tube formation, and irradiation among patients who underwent free jejunal flap transfer.

Methods:
We retrospectively examined 100 cases (88 men and 12 women; average age, 65.8 years; range, 46–88 years) in whom the evaluation of postoperative oral intake was possible after undergoing total pharyngo-laryngo-esophagectomy (TPLE) and free jejunal flap transfer. Chi-square test (with Fisher transformation, if necessary) was performed to analyze the relationship among resection styles (the resection margin extended to the oropharynx or to the cervical esophagus and gastric tube elevation), radiation therapy history, and incidence of dysphagia or fistula formation.

Results:
One hundred patients were analyzed, and complications such as postoperative fistula and dysphagia occurred in 8 (8.0%) and 20 patients (20.0%), respectively. However, no significant correlation was found between various resection factors and fistula formation or adverse events. At the reconstruction site, other complications such as postoperative lymphorrhea (7%), postoperative hematoma (4%), trachea necrosis (4%), cervical flap necrosis (1%), and thyroid necrosis (1%) occurred. These complications were managed by a cervical open wound and additional minor operation as needed.

Conclusion:
Thus, free jejunal transfer for TPLE is a good reconstruction technique with few complications and postoperative adverse events, regardless of the extent of resection and preoperative radiation therapy.