bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spontaneous intra-adrenal massive hematoma: possible extreme evolution of a non-secreting untreated adrenal adenoma
Authors: Mancini Mariangela , Leone Nicolò , Iafrate Massimo , Fassina Ambrogio , Zattoni Filiberto ,   in collaboration with European Reference Network for Rare Urogenital Diseases and Complex Conditions (ERN eUROGEN)
Published: May 2020

Abstract
The spontaneous adrenal hematoma is a rare event. An 83-year-old male patient presented a 26-cm asymptomatic retroperitoneal mass of doubtful renal–adrenal origin. He had been evaluated 10 years before for an adrenal incidentaloma of 2.3 cm and had refused surgery when it had reached 7 cm. Later, the mass enlarged to 26 cm and was surgically removed through an open anterior approach. The histopathology showed a solid 4 kg mass of fibrinoid–hemorrhagic material, partially necrotic, mixed with adrenal tissue, with a well-vascularized capsule. No relapse is present at 6-month follow-up. This is the largest case described of spontaneous intra-adrenal hematoma in a case with previous non-secreting adrenal adenoma. The hematoma (a 4 kg mass) developed 10 years after the first diagnosis and exposed the patient to potential damage of the surrounding organs and to high-risk abdominal surgery. Long-term follow-up of non-secreting adrenal adenomas should be recommended.
Streamlining Definitive Care for Occult Scaphoid Fractures: A Retrospective Review of the Workup of Scaphoid Nonunions and Applying Lessons Learned
Authors: Liu Peterson Shian , Scott Donoughe John , O’Neal Derrick , Mombell Kyle , GomezLeonardelli Dominic 
Published: May 2020

Abstract

Introduction
The process for working up scaphoid fractures from frontline providers to the specialty care clinic is variable. Initial imaging can often be negative and the management algorithm is not clearly defined. Delays in diagnosis are a contributing factor to scaphoid nonunion. Fractures may not be identified by frontline providers on initial presentation because of radiographically occult injuries. If not treated promptly, scaphoid fractures may be complicated by nonunion, avascular necrosis, and osteoarthritis.

Materials and Methods
Retrospective review of scaphoid nonunions from 2017 to 2018 in a single tertiary care institution after internal review board approval was obtained (NMCSD.QI.2019.0003). Cases were identified using an ICD 10 search for “scaphoid (navicular) fracture non-union” and subtypes. Charts were examined for time between injury and presentation, injury and diagnosis, initial radiologic workup, and limited duty (LIMDU). Nonparametric statistical analysis for linear and categorical data was conducted using SPSS. A subgroup of patients who had a delay in diagnosis of greater than 30 days upon entering the medical system was further analyzed and identified as the “delayed diagnosis” cohort.

Results
In total, 30 patients with scaphoid nonunion were identified. Overall, 35% of patients had negative initial X-rays and averaged 42.1 days until diagnosis. In total, 100% of patients required at least one LIMDU period, averaging 1.4 periods, for a total of 6,404 days and 16% went on to a physical evaluation board (PEB). In 9 (30%) of these patients, injury was initially not identified upon entering the medical system resulting in average of 139.7 days until diagnosis; this became known as the delayed diagnosis subgroup. Further analysis of the delayed diagnosis subgroup demonstrated significantly more initial negative X-rays (P &lt; .005) at a rate of 77% (7/9). A delay in diagnosis was significantly associated with PEB (R = 0.4, P = .031) with 33% of these patients going on to a PEB.

Conclusions
Delayed diagnosis of a scaphoid fracture is a contributing factor for excessive light duty, high rates of LIMDU utilization, and ultimately medical separation of service members. Overall, in all patients who had scaphoid nonunions, the average time to diagnosis was 42.1 days with 35% of patients presenting with negative initial imaging. A delayed diagnosis subgroup was identified and notable for a higher rate of initial negative X-rays, an average of 139.7 days until diagnosis, and a 33% PEB rate. In total, 77% of patients with a delay in diagnosis of more than 30 days had an initial negative X-ray. An evidence-based algorithm for diagnosing occult scaphoid fractures may prevent delays in diagnosis, thus increasing the readiness of active duty service members.
Trapped orbits and solar-neighbourhood kinematics
Authors: Binney James 
Published: May 2020

ABSTRACT
Torus mapping yields constants of motion for stars trapped at a resonance. Each such constant of motion yields a system of contours in velocity space at the Sun and neighbouring points. If Jeans’ theorem applied to resonantly trapped orbits, the density of stars in velocity space would be equal at all intersections of any two contours. A quantitative measure of the violation of this principle is defined and used to assess various pattern speeds for a model of the bar recently fitted to observations of interstellar gas. Trapping at corotation of a bar with pattern speed near $36\, \mathrm{Gyr}^{-1}$ is favoured and trapping at the outer Lindblad resonance is disfavoured. As one moves around the Sun the structure of velocity space varies quite rapidly, both as regards the observed star density and the zones of trapped orbits. The data seem consistent with trapping at corotation.
Using realistic host galaxy metallicities to improve the GRB X-ray equivalent total hydrogen column density and constrain the intergalactic medium density
Authors: Dalton Tony , Morris Simon L 
Published: May 2020

ABSTRACT
It is known that the GRB equivalent hydrogen column density (NHX) changes with redshift and that, typically, NHX is greater than the GRB host neutral hydrogen column density. We have compiled a large sample of data for GRB NHX and metallicity [X/H]. The main aims of this paper are to generate improved NHX for our sample by using actual metallicities, dust corrected where available for detections, and for the remaining GRB, a more realistic average intrinsic metallicity using a standard adjustment from solar. Then, by approximating the GRB host intrinsic hydrogen column density using the measured neutral column (NHI, IC) adjusted for the ionization fraction, we isolate a more accurate estimate for the intergalactic medium (IGM) contribution. The GRB sample mean metallicity is = −1.17 ± 0.09 rms (or 0.07 ± 0.05 Z/Zsol) from a sample of 36 GRB with a redshift 1.76 ≤ z ≤ 5.91, substantially lower than the assumption of solar metallicity used as standard for many fitted NHX. Lower GRB host mean metallicity results in increased estimated NHX with the correction scaling with redshift as Δlog (NHX cm−2) = (0.59 ± 0.04)log(1 + z) + 0.18 ± 0.02. Of the 128 GRB with data for both NHX and NHI, IC in our sample, only six have NHI, IC &gt; NHX when revised for realistic metallicity, compared to 32 when solar metallicity is assumed. The lower envelope of the revised NHX – NHI, IC, plotted against redshift can be fit by log(NHX – NHI, IC cm−2) = 20.3 + 2.4 log(1 + z). This is taken to be an estimate for the maximum IGM hydrogen column density as a function of redshift. Using this approach, we estimate an upper limit to the hydrogen density at redshift zero (n0) to be consistent with n0 = 0.17 × 10−7cm−3.
Long-term evolution of a magnetic massive merger product
Authors: Schneider F R N , Ohlmann S T , Podsiadlowski Ph , Röpke F K , Balbus S A , Pakmor R 
Published: May 2020

ABSTRACT
About 10 per cent of stars more massive than ${\approx}1.5\, {\mathrm{M}}_{\odot }$ have strong, large-scale surface magnetic fields and are being discussed as progenitors of highly magnetic white dwarfs and magnetars. The origin of these fields remains uncertain. Recent three-dimensional (3D) magnetohydrodynamical simulations have shown that strong magnetic fields can be generated in the merger of two massive stars. Here, we follow the long-term evolution of such a 3D merger product in a 1D stellar evolution code. During a thermal relaxation phase after the coalescence, the merger product reaches critical surface rotation, sheds mass and then spins down primarily because of internal mass readjustments. The spin of the merger product after thermal relaxation is mainly set by the co-evolution of the star–torus structure left after coalescence. This evolution is still uncertain, so we also consider magnetic braking and other angular momentum-gain and -loss mechanisms that may influence the final spin of the merged star. Because of core compression and mixing of carbon and nitrogen in the merger, enhanced nuclear burning drives a transient convective core that greatly contributes to the rejuvenation of the star. Once the merger product relaxed back to the main sequence, it continues its evolution similar to that of a genuine single star of comparable mass. It is a slow rotator that matches the magnetic blue straggler τ Sco. Our results show that merging is a promising mechanism to explain some magnetic massive stars and it may also be key to understand the origin of the strong magnetic fields of highly magnetic white dwarfs and magnetars.
The SAMI Galaxy Survey: decomposed stellar kinematics of galaxy bulges and disks
Authors: Oh Sree , Colless Matthew , Barsanti Stefania , Casura Sarah , Cortese Luca , van de Sande Jesse , Owers Matt S , Scott Nicholas , D’Eugenio Francesco , Bland-Hawthorn Joss , Brough Sarah , Bryant Julia J , Croom Scott M , Foster Caroline , Groves Brent , Lawrence Jon S , Richards Samuel N , Sweet Sarah M 
Published: May 2020

ABSTRACT
We investigate the stellar kinematics of the bulge and disk components in 826 galaxies with a wide range of morphology from the Sydney-AAO Multi-object Integral-field spectroscopy Galaxy Survey. The spatially resolved rotation velocity (V) and velocity dispersion (σ) of bulge and disk components have been simultaneously estimated using the penalized pixel fitting (ppxf) method with photometrically defined weights for the two components. We introduce a new subroutine of ppxf for dealing with degeneracy in the solutions. We show that the V and σ distributions in each galaxy can be reconstructed using the kinematics and weights of the bulge and disk components. The combination of two distinct components provides a consistent description of the major kinematic features of galaxies over a wide range of morphological types. We present Tully–Fisher and Faber–Jackson relations showing that the galaxy stellar mass scales with both V and σ for both components of all galaxy types. We find a tight Faber–Jackson relation even for the disk component. We show that the bulge and disk components are kinematically distinct: (1) the two components show scaling relations with similar slopes, but different intercepts; (2) the spin parameter λR indicates bulges are pressure-dominated systems and disks are supported by rotation; and (3) the bulge and disk components have, respectively, low and high values in intrinsic ellipticity. Our findings suggest that the relative contributions of the two components explain, at least to first order, the complex kinematic behaviour of galaxies.
On the origin of the bimodal rotational velocity distribution in stellar clusters: rotation on the pre-main sequence
Authors: Bastian Nate , Kamann Sebastian , Amard Louis , Charbonnel Corinne , Haemmerlé Lionel , Matt Sean P 
Published: May 2020

ABSTRACT
We address the origin of the observed bimodal rotational distribution of stars in massive young and intermediate age stellar clusters. This bimodality is seen as split main sequences at young ages and also has been recently directly observed in the Vsini distribution of stars within massive young and intermediate age clusters. Previous models have invoked binary interactions as the origin of this bimodality, although these models are unable to reproduce all of the observational constraints on the problem. Here, we suggest that such a bimodal rotational distribution is set-up early within a cluster’s life, i.e. within the first few Myr. Observations show that the period distribution of low-mass ($\lesssim\! 2 \, \mathrm{M}_\odot$) pre-main-sequence (PMS) stars is bimodal in many young open clusters, and we present a series of models to show that if such a bimodality exists for stars on the PMS that it is expected to manifest as a bimodal rotational velocity (at fixed mass/luminosity) on the main sequence for stars with masses in excess of ∼1.5 M⊙. Such a bimodal period distribution of PMS stars may be caused by whether stars have lost (rapid rotators) or been able to retain (slow rotators) their circumstellar discs throughout their PMS lifetimes. We conclude with a series of predictions for observables based on our model.
The optical polarization of the blazar PKS 2155–304 during an optical flare in 2010
Authors: Peceur N W , Taylor A R , Kraan-Korteweg R C 
Published: May 2020

ABSTRACT
An analysis is presented of the optical polarimetric and multicolour photometric (BVRJ) behaviour of the blazar PKS 2155–304 during an outburst in 2010. This flare develops over roughly 117 d, with a flux doubling time τ ∼ 11 d, which increases from blue to red wavelengths. The polarization angle is initially aligned with the jet axis but rotates by roughly 90° as the flare grows. Two distinct states are evident at low and high fluxes. Below 18 mJy, the polarization angle takes on a wide range of values, without any clear relation to the flux. In contrast, there is a positive correlation between the polarization angle and flux above 18 mJy. The polarization degree does not display a clear correlation with the flux. We find that the photopolarimetric behaviour for the high flux state can be attributed to a variable component with a steady power-law spectral energy distribution and high optical polarization degree (13.3 per cent). These properties are interpreted within the shock-in-jet model, which shows that the observed variability can be explained by a shock that is seen nearly edge-on. Some parameters derived for the relativistic jet within the shock-in-jet model are: B = 0.06 G for the magnetic field, δ = 22.3 for the Doppler factor, and Φ = 2.6° for the viewing angle.
Non-ideal magnetohydrodynamics versus turbulence II: Which is the dominant process in stellar core formation?
Authors: Wurster James , Lewis Benjamin T 
Published: May 2020

ABSTRACT
Non-ideal magnetohydrodynamics (MHD) is the dominant process. We investigate the effect of magnetic fields (ideal and non-ideal) and turbulence (sub- and transsonic) on the formation of protostars by following the gravitational collapse of 1 M⊙ gas clouds through the first hydrostatic core to stellar densities. The clouds are imposed with both rotational and turbulent velocities, and are threaded with a magnetic field that is parallel/antiparallel or perpendicular to the rotation axis; we investigate two rotation rates and four Mach numbers. The initial radius and mass of the stellar core are only weakly dependent on the initial parameters. In the models that include ideal MHD, the magnetic field strength implanted in the protostar at birth is much higher than observed, independent of the initial level of turbulence; only non-ideal MHD can reduce this strength to near or below the observed levels. This suggests that not only is ideal MHD an incomplete picture of star formation, but that the magnetic fields in low mass stars are implanted later in life by a dynamo process. Non-ideal MHD suppresses magnetically launched stellar core outflows, but turbulence permits thermally launched outflows to form a few years after stellar core formation.
Large-scale changes of the cloud coverage in the ϵ Indi Ba and Bb system
Authors: Hitchcock J A , Helling Ch , Scholz A , Hodosan G , Dominik M , Hundertmark M , Jørgensen U G , Longa-Peña P , Sajadian S , Skottfelt J , Snodgrass C , Bozza V , Burgdorf M J , Campbell-White J , Figuera Jaimes Roberto , Fujii Y I , Haikala L K , Henning T , Hinse T C , Lowry S , Mancini L , Rahvar S , Rabus M , Southworth J , von Essen C ,   (The MiNDSTEp Collaboration)
Published: May 2020

ABSTRACT
We present the results of 14 nights of I-band photometric monitoring of the nearby brown dwarf binary, ϵ Indi Ba and Bb. Observations were acquired over 2 months, with a total of close to 42 h of coverage at a typically high cadence of 1.4 min. At a separation of just 0.7 arcsec, we do not resolve the individual components, and so effectively treat the binary as if it were a single object. However, ϵ Indi Ba (spectral type T1) is the brightest known T-type brown dwarf, and is expected to dominate the photometric signal. We typically find no strong variability associated with the target during each individual night of observing, but see significant changes in mean brightness – by as much as 0.10 mag – over the 2 months of the campaign. This strong variation is apparent on a time-scale of at least 2 d. We detect no clear periodic signature, which suggests that we may be observing the T1 brown dwarf almost pole-on, and the days-long variability in mean brightness is caused by changes in the large-scale structure of the cloud coverage. Dynamic clouds will very likely produce lightning, and complementary high-cadence V-band and H α images were acquired to search for the emission signatures associated with stochastic ‘strikes’. We report no positive detections for the target in either of these passbands.
Carbon stars as standard candles: I. The luminosity function of carbon stars in the Magellanic Clouds
Authors: Ripoche Paul , Heyl Jeremy , Parada Javiera , Richer Harvey 
Published: May 2020

ABSTRACT
Our goal in this paper is to derive a carbon-star luminosity function that will eventually be used to determine distances to galaxies at 50–60 Mpc and hence yield a value of the Hubble constant. Cool N-type carbon stars exhibit redder near-infrared colours than oxygen-rich stars. Using Two Micron All Sky Survey near-infrared photometry and the Gaia Data Release 2, we identify carbon stars in the Magellanic Clouds (MC) and the Milky Way (MW). Carbon stars in the MC appear as a distinct horizontal feature in the near-infrared ((J − Ks)0, MJ) colour–magnitude diagram. We build a colour selection (1.4 &lt; (J − Ks)0 &lt; 2) and derive the luminosity function of the colour-selected carbon stars. We find the median absolute magnitude and the dispersion, in the J band, for the Large and the Small Magellanic Clouds (LMC/SMC) to be, respectively, ($\bar{M_J} = -6.284~\pm ~0.004$ and σ = 0.352 ± 0.005) and ($\bar{M_J} = -6.160~\pm ~0.015$ and σ = 0.365 ± 0.014). The difference between the MC may be explained by the lower metallicity of the SMC, but in any case it provides limits on the type of galaxy whose distance can be determined with this technique. To account for metallicity effects, we developed a composite magnitude, named C, for which the error-weighted mean C magnitude of the MC are equal. Thanks to the next generation of telescopes (JWST, ELT, and TMT), carbon stars could be detected in MC-type galaxies at distances out to 50–60 Mpc. The final goal is to eventually try and improve the measurement of the Hubble constant while exploring the current tensions related to its value.
Stability of Jovian Trojans and their collisional families
Authors: Holt Timothy R , Nesvorný David , Horner Jonathan , King Rachel , Marschall Raphael , Kamrowski Melissa , Carter Brad , Brookshaw Leigh , Tylor Christopher 
Published: May 2020

ABSTRACT
The Jovian Trojans are two swarms of objects located around the L4 and L5 Lagrange points. The population is thought to have been captured by Jupiter during the Solar system’s youth. Within the swarms, six collisional families have been identified in previous work, with four in the L4 swarm, and two in the L5. Our aim is to investigate the stability of the two Trojan swarms, with a particular focus on these collisional families. We find that the members of Trojan swarms escape the population at a linear rate, with the primordial L4 (23.35 per cent escape) and L5 (24.89 per cent escape) population sizes likely 1.31 and 1.35 times larger than today. Given that the escape rates were approximately equal between the two Trojan swarms, our results do not explain the observed asymmetry between the two groups, suggesting that the numerical differences are primordial in nature, supporting previous studies. Upon leaving the Trojan population, the escaped objects move on to orbits that resemble those of the Centaur and short-period comet populations. Within the Trojan collisional families, the 1996 RJ and 2001 UV209 families are found to be dynamically stable over the lifetime of the Solar system, whilst the Hektor, Arkesilos and Ennomos families exhibit various degrees of instability. The larger Eurybates family shows 18.81 per cent of simulated members escaping the Trojan population. Unlike the L4 swarm, the escape rate from the Eurybates family is found to increase as a function of time, allowing an age estimation of approximately 1.045 ± 0.364 × 109 yr.
Chaotically magnetized atmosphere with dust
Authors: Silant’ev N A , Alekseeva G A , Ananjevskaja Yu K 
Published: May 2020

ABSTRACT
We consider the influence of absorbing dust particles on the intensity and polarization of radiation in chaotically magnetized atmospheres. The Milne problem is considered. It is known that the existence of absorbing dust particles leads to more elongated intensity distribution along the normal to the atmosphere and increasing of polarization degree near the direction perpendicular to the normal. The chaotic Faraday rotations practically do not change the intensity distribution, but they decrease the polarization degree. How looks the picture when the atmosphere is chaotically magnetized and contains the absorbing dust particles? Usually one assumes that such atmospheres exist in active galactic nuclei in Seyfert galaxies, both in accretion discs and gas–dusty toruses. In particular, we establish when both mechanisms cancel one another and the resulting polarization is near to ordinary atmosphere without the magnetic field fluctuations and absorbing particles. Of course, the angular distribution mostly corresponds to the level of existing dust particles, because it is practically independent of polarization.
From birth associations to field stars: mapping the small-scale orbit distribution in the Galactic disc
Authors: Coronado Johanna , Rix Hans-Walter , Trick Wilma H , El-Badry Kareem , Rybizki Jan , Xiang Maosheng 
Published: May 2020

ABSTRACT
Stars born at the same time in the same place should have formed from gas of the same element composition. But most stars subsequently disperse from their birth siblings, in orbit and orbital phase, becoming ‘field stars’. Here, we explore and provide direct observational evidence for this process in the Milky Way disc, by quantifying the probability that orbit-similarity among stars implies indistinguishable metallicity. We define the orbit similarity among stars through their distance in action-angle space, Δ(J, θ), and their abundance similarity simply by Δ[Fe/H]. Analysing a sample of main-sequence stars from Gaia DR2 and LAMOST, we find an excess of pairs with the same metallicity (Δ[Fe/H] &lt; 0.1) that extends to remarkably large separations in Δ(J, θ) that correspond to nearly 1 kpc distances. We assess the significance of this effect through a mock sample, drawn from a smooth and phase-mixed orbit distribution. Through grouping such star pairs into associations with a friend-of-friends algorithm linked by Δ(J,θ), we find 100s of mono-abundance groups with ≥3 (to ≳20) members; these groups – some clusters, some spread across the sky – are over an order-of-magnitude more abundant than expected for a smooth phase-space distribution, suggesting that we are witnessing the ‘dissolution’ of stellar birth associations into the field.