bluuebunny/crossref_metadata_2025_split huggingface dataset:
Star Formation Rate Distribution in the Galaxy NGC 1232
Authors: de Souza Alexandre Araújo , Martins Lucimara P. , Rodríguez-Ardila Alberto , Fraga Luciano 
Published: May 2018

Abstract
NGC 1232 is a face-on spiral galaxy and a great laboratory for the study of star formation due to its proximity. We obtained high spatial resolution Hα images of this galaxy, with adaptive optics, using the SAM instrument at the SOAR telescope, and used these images to study its H ii regions. These observations allowed us to produce the most complete H ii region catalog for it to date, with a total of 976 sources. This doubles the number of H ii regions previously found for this object. We used these data to construct the H ii luminosity function, and obtained a power-law index lower than the typical values found for Sc galaxies. This shallower slope is related to the presence of a significant number of high-luminosity H ii regions (log L > 39 dex). We also constructed the size distribution function, verifying that, as for most galaxies, NGC 1232 follows an exponential law. We also used the Hα luminosity to calculate the star formation rate. An extremely interesting fact about this galaxy is that X-ray diffuse observations suggest that NGC 1232 recently suffered a collision with a dwarf galaxy. We found an absence of star formation around the region where the X-ray emission is more intense, which we interpret as a star formation quenching due to the collision. Along with that, we found an excess of star-forming regions in the northeast part of the galaxy, where the X-ray emission is less intense.
The Direct Imaging Search for Earth 2.0: Quantifying Biases and Planetary False Positives
Authors: Guimond Claire Marie , Cowan Nicolas B. 
Published: May 2018

Abstract
Direct imaging is likely the best way to characterize the atmospheres of Earth-sized exoplanets in the habitable zone of Sun-like stars. Previously, Stark et al. estimated the Earth twin yield of future direct imaging missions, such as LUVOIR and HabEx. We extend this analysis to other types of planets, which will act as false positives for Earth twins. We define an Earth twin as any exoplanet within half an e-folding of 1 au in semimajor axis and 1

in planetary radius, orbiting a G-dwarf. Using Monte Carlo analyses, we quantify the biases and planetary false-positive rates of Earth searches. That is, given a pale dot at the correct projected separation and brightness to be a candidate Earth, what are the odds that it is, in fact, an Earth twin? Our notional telescope has a diameter of 10 m, an inner working angle of 3λ/D, and an outer working angle of 10λ/D (62 mas and 206 mas at 1.0 μm). With no precursor knowledge and one visit per star, 77% of detected candidate Earths are actually un-Earths; their mean radius is 2.3

, a sub-Neptune. The odds improve if we image every planet at its optimal orbital phase, either by relying on precursor knowledge, or by performing multi-epoch direct imaging. In such a targeted search, 47% of detected Earth twin candidates are false positives, and they have a mean radius of 1.7

. The false-positive rate is insensitive to stellar spectral type and the assumption of circular orbits.
Broadband X-Ray Spectral Analysis of the Double-nucleus Luminous Infrared Galaxy Mrk 463
Authors: Yamada Satoshi , Ueda Yoshihiro , Oda Saeko , Tanimoto Atsushi , Imanishi Masatoshi , Terashima Yuichi , Ricci Claudio 
Published: May 2018

Abstract
We present a broadband (0.4–70 keV) X-ray spectral analysis of the luminous infrared galaxy (LIRG) system Mrk 463 observed with Nuclear Spectroscopic Telescope Array (NuSTAR), Chandra, and XMM-Newton, which contains double active galactic nuclei (AGNs; Mrk 463E and Mrk 463W) with a separation of ∼3.8 kpc. Detecting their transmitted hard X-ray >10 keV continua with NuSTAR, we confirm that Mrk 463E and Mrk 463W have AGNs with intrinsic luminosities of (1.6–2.2) × 1043 and (0.5–0.6) × 1043 erg s−1 (2–10 keV) obscured by hydrogen column densities of 8 × 1023 and 3 × 1023 cm−2, respectively. Both nuclei show strong reflection components from cold matter. The luminosity ratio between X-ray (2–10 keV) and [O iv] 25.89 μm of Mrk 463E is ∼5 times smaller than those of normal Seyfert galaxies, suggesting that the intrinsic SED is X-ray weak relative to the UV luminosity. In fact, the bolometric AGN luminosity of Mrk 463E estimated from L′-band (3.8 μm), [O iv] 25.89 μm, and [Ne v] 14.32 μm lines indicate a large bolometric-to-X-ray luminosity ratio, κ
2–10 keV ≈ 110–410, and a high Eddington ratio, λ
Edd ∼ 0.4–0.8. We suggest that the merger triggered a rapid growth of the black hole in Mrk 463E, which is not yet deeply “buried” by circumnuclear dust. By contrast, the L′-band luminosity of Mrk 463W is unusually small relative to the X-ray luminosity, suggesting that the Eddington ratio is low (<10−3) and it might be still in an early phase of merger-driven AGN activity.
The Unified Astronomy Thesaurus: Semantic Metadata for Astronomy and Astrophysics
Authors: Frey Katie , Accomazzi Alberto 
Published: May 2018

Abstract
Several controlled vocabularies have been developed and used by the astronomical community, each designed to serve a specific need and a specific group. The Unified Astronomy Thesaurus (UAT) attempts to provide a highly structured controlled vocabulary that will be relevant and useful across the entire discipline, regardless of content or platform. Because classifying articles and data will be the two major functions of the UAT, we examine the UAT in comparison with the Astronomical Subject Keywords used by major publications and the JWST Science Keywords used by STScI’s Astronomer’s Proposal Tool.
Data Analysis Recipes: Using Markov Chain Monte Carlo*
Authors: Hogg David W. , Foreman-Mackey Daniel 
Published: May 2018

Abstract
Markov Chain Monte Carlo (MCMC) methods for sampling probability density functions (combined with abundant computational resources) have transformed the sciences, especially in performing probabilistic inferences, or fitting models to data. In this primarily pedagogical contribution, we give a brief overview of the most basic MCMC method and some practical advice for the use of MCMC in real inference problems. We give advice on method choice, tuning for performance, methods for initialization, tests of convergence, troubleshooting, and use of the chain output to produce or report parameter estimates with associated uncertainties. We argue that autocorrelation time is the most important test for convergence, as it directly connects to the uncertainty on the sampling estimate of any quantity of interest. We emphasize that sampling is a method for doing integrals; this guides our thinking about how MCMC output is best used.
sunstardb: A Database for the Study of Stellar Magnetism and the Solar-stellar Connection
Authors: Egeland Ricky 
Published: May 2018

Abstract
The “solar-stellar connection” began as a relatively small field of research focused on understanding the processes that generate magnetic fields in stars and sometimes lead to a cyclic pattern of long-term variability in activity, as demonstrated by our Sun. This area of study has recently become more broadly pertinent to questions of exoplanet habitability and exo-space weather, as well as stellar evolution. In contrast to other areas of stellar research, individual stars in the solar-stellar connection often have a distinct identity and character in the literature, due primarily to the rarity of the decades-long time-series that are necessary for studying stellar activity cycles. Furthermore, the underlying stellar dynamo is not well understood theoretically, and is thought to be sensitive to several stellar properties, e.g., luminosity, differential rotation, and the depth of the convection zone, which in turn are often parameterized by other more readily available properties. Relevant observations are scattered throughout the literature and existing stellar databases, and consolidating information for new studies is a tedious and laborious exercise. To accelerate research in this area I developed sunstardb, a relational database of stellar properties and magnetic activity proxy time-series keyed by individual named stars. The organization of the data eliminates the need for the problematic catalog cross-matching operations inherent when building an analysis data set from heterogeneous sources. In this article I describe the principles behind sunstardb, the data structures and programming interfaces, as well as use cases from solar-stellar connection research.
AAS WorldWide Telescope: A Seamless, Cross-platform Data Visualization Engine for Astronomy Research, Education, and Democratizing Data
Authors: Rosenfield Philip , Fay Jonathan , Gilchrist Ronald K , Cui Chenzhou , Weigel A. David , Robitaille Thomas , Otor Oderah Justin , Goodman Alyssa 
Published: May 2018

Abstract
The American Astronomical Society’s WorldWide Telescope (WWT) project enables terabytes of astronomical images, data, and stories to be viewed and shared among researchers, exhibited in science museums, projected into full-dome immersive planetariums and virtual reality headsets, and taught in classrooms, from middle school to college. We review the WWT ecosystem, how WWT has been used in the astronomical community, and comment on future directions.
Cyberhubs: Virtual Research Environments for Astronomy
Authors: Herwig Falk , Andrassy Robert , Annau Nic , Clarkson Ondrea , Côté Benoit , D’Sa Aaron , Jones Sam , Moa Belaid , O’Connell Jericho , Porter David , Ritter Christian , Woodward Paul 
Published: May 2018

Abstract
Collaborations in astronomy and astrophysics are faced with numerous cyber-infrastructure challenges, such as large data sets, the need to combine heterogeneous data sets, and the challenge to effectively collaborate on those large, heterogeneous data sets with significant processing requirements and complex science software tools. The cyberhubs system is an easy-to-deploy package for small- to medium-sized collaborations based on the Jupyter and Docker technology, which allows web-browser-enabled, remote, interactive analytic access to shared data. It offers an initial step to address these challenges. The features and deployment steps of the system are described, as well as the requirements collection through an account of the different approaches to data structuring, handling, and available analytic tools for the NuGrid and PPMstar collaborations. NuGrid is an international collaboration that creates stellar evolution and explosion physics and nucleosynthesis simulation data. The PPMstar collaboration performs large-scale 3D stellar hydrodynamics simulations of interior convection in the late phases of stellar evolution. Examples of science that is currently performed on cyberhubs, in the areas of 3D stellar hydrodynamic simulations, stellar evolution and nucleosynthesis, and Galactic chemical evolution, are presented.
On the Use of Hydrogen Recombination Energy during Common Envelope Events
Authors: Ivanova Natalia 
Published: May 2018

Abstract
In this Letter we discuss what happens to hydrogen recombination energy that is released during regular common envelope (CE) events as opposed to self-regulated CE events. We show that the amount of recombination energy that can be transferred away by either convection or radiation from the regions where recombination takes place is negligible. Instead, recombination energy is destined to be used either to help CE expansion, as a work term, or to accelerate local fluid elements. The exceptions are donors that initially have very high entropy material, S/(k
B
N
A) > 37 mol g−1. The analysis and conclusions are independent of specific stellar models or evolutionary codes, and rely on fundamental properties of stellar matter such as the equation of state, Saha equation, and opacities, as well as on stellar structure equations and the mixing length theory of convection.
Measurements of the Activation Energies for Atomic Hydrogen Diffusion on Pure Solid CO
Authors: Kimura Y. , Tsuge M. , Pirronello V. , Kouchi A. , Watanabe N. 
Published: May 2018

Abstract
The diffusion of hydrogen atoms on dust grains is a key process in the formation of interstellar H2 and some hydrogenated molecules such as formaldehyde and methanol. We investigate the adsorption and diffusion of H atoms on pure solid CO as an analog of dust surfaces observed toward some cold interstellar regions. Using a combination of photostimulated desorption and resonance-enhanced multiphoton ionization methods to detect H atoms directly, the relative adsorption probabilities and diffusion coefficients of the H atoms are measured on pure solid CO at 8, 12, and 15 K. There is little difference between the diffusion coefficients of the hydrogen and deuterium atoms, indicating that the diffusion is limited by thermal hopping. The activation energies controlling the H-atom diffusion depend on the surface temperature, and values of 22, 30, and ∼37 meV were obtained for 8, 12, and 15 K, respectively.
Two New Super Li-rich Core He-burning Giants: A New Twist to the Long Tale of Li Enhancement in K Giants
Authors: Kumar Yerra Bharat , Singh Raghubar , Reddy B. Eswar , Zhao Gang 
Published: May 2018

Abstract
In this Letter we report two new super Li-rich K giants, KIC2305930 and KIC12645107, with Li abundances exceeding that of the interstellar medium (ISM; A(Li) ≥ 3.2 dex). Importantly, both of the giants have been classified as core He-burning red clump (RC) stars based on asteroseismic data from Kepler mission. Also, both of the stars are found to be low mass (M ≈ 1.0 M
⊙), which, together with an evidence of their evolutionary status of being RC stars, implies that the stars have gone through both the luminosity bump and He-flash during their red giant branch (RGB) evolution. The stars’ large Li abundance and evolutionary phase suggest that Li enrichment occurred very recently, probably at the tip of the RGB either during He-flash, an immediate preceding event on the RGB, or by some kind of external event such as merger of an RGB star with white dwarf. The findings will provide critical constraints to theoretical models for understanding of Li enhancement origin in RGB stars.
Extracellular Histones Inhibit Complement Activation through Interacting with Complement Component 4
Authors: Qaddoori Yasir , Abrams Simon T. , Mould Paul , Alhamdi Yasir , Christmas Stephen E. , Wang Guozheng , Toh Cheng-Hock 
Published: May 2018

Abstract
Complement activation leads to membrane attack complex formation, which can lyse not only pathogens but also host cells. Histones can be released from the lysed or damaged cells and serve as a major type of damage-associated molecular pattern, but their effects on the complement system are not clear. In this study, we pulled down two major proteins from human serum using histone-conjugated beads: one was C-reactive protein and the other was C4, as identified by mass spectrometry. In surface plasmon resonance analysis, histone H3 and H4 showed stronger binding to C4 than other histones, with KD around 1 nM. The interaction did not affect C4 cleavage to C4a and C4b. Because histones bind to C4b, a component of C3 and C5 convertases, their activities were significantly inhibited in the presence of histones. Although it is not clear whether the inhibition was achieved through blocking C3 and C5 convertase assembly or just through reducing their activity, the outcome was that both classical and mannose-binding lectin pathways were dramatically inhibited. Using a high concentration of C4 protein, histone-suppressed complement activity could not be fully restored, indicating C4 is not the only target of histones in those pathways. In contrast, the alternative pathway was almost spared, but the overall complement activity activated by zymosan was inhibited by histones. Therefore, we believe that histones inhibiting complement activation is a natural feedback mechanism to prevent the excessive injury of host cells.
Formation of Immune Complexes with a Tetanus-Derived B Cell Epitope Boosts Human T Cell Responses to Covalently Linked Peptides in an Ex Vivo Blood Loop System
Authors: Fletcher Erika A. K. , van Maren Wendy , Cordfunke Robert , Dinkelaar Jasper , Codee Jeroen D. C. , van der Marel Gijs , Melief Cornelis J. M. , Ossendorp Ferry , Drijfhout Jan Wouter , Mangsbo Sara M. 
Published: May 2018

Abstract
Enhancing T cell responses against both viral and tumor Ags requires efficient costimulation and directed delivery of peptide Ags into APCs. Long peptide vaccines are considered favorable vaccine moieties from a clinical perspective, as they can harbor more than one immunogenic epitope enabling treatment of a broader target population. In addition, longer peptides are not extracellularly loaded on MHC class I; rather, they require intracellular processing and will thereby be presented to T cells mainly by professional APCs, thereby avoiding the risk of tolerance induction. The drawback of peptide vaccines regardless of peptide length is that naked peptides are not actively targeted to and taken up by APCs, and the standard nonconjugated adjuvant-peptide mixtures do not ensure cotargeting of the two to the same APC. We have identified a tetanus toxin–derived B cell epitope that can mediate the formation of immune complexes in the presence of circulating Abs. In this study, we show that these immune complexes improve both Ag uptake by APCs (blood monocytes and CD1c+ dendritic cells) and consequently improve CD8+ T cell recall responses in a human ex vivo blood loop system. The uptake of the peptide conjugate by blood monocytes is dependent on Abs and the complement component C1q. We envision that this strategy can be used to facilitate active uptake of Ags into APCs to improve T cell responses against pathogens or cancer.
LE DESSINATEUR BRETON THÉOPHILE BUSNEL AU QUÉBEC
Authors: DANAUX STÉPHANIE 
Published: May 2018

Dès son arrivée à Montréal en 1904, le jeune dessinateur français Théophile Busnel
est recruté comme dessinateur au journal La Patrie pour poursuivre la série
« Timothée », créée par Albéric Bourgeois. À l’été 1908, il doit toutefois regagner sa
Bretagne natale, où il meurt des suites d’une longue maladie. Aussi brève soit-elle, la
présence de Busnel à Montréal coïncide avec le début en 1904 et le déclin à partir de 1908
de la bande dessinée dans la presse francophone au Québec, progressivement remplacée par des
importations américaines, puis françaises. Sans être à l’origine de cet âge d’or, Busnel s’y
associe presque aussitôt et en devient l’un des principaux acteurs. Cet article met en
lumière, à partir d’un corpus de dessins publiés dans La Patrie, la contribution de
Busnel à l’histoire de la bande dessinée et du dessin d’humour au Québec en examinant ses
interactions avec Bourgeois et en évaluant la part de ses innovations graphiques, narratives
et iconographiques.
« N’HÉSITEZ PAS À JOUER LA CARTE DE L’HISTOIRE VÉCUE »
Authors: BEAULIEU JEAN-PHILIPPE 
Published: May 2018

Décrit comme un récit autobiographique par sa quatrième de couverture, Tuer
Vélasquez (2009) de Philippe Girard rapporte une situation d’abus sexuel par un prêtre
dont l’auteur a été témoin en 1983. L’écriture de soi se manifeste toutefois plutôt
discrètement dans cet ouvrage, qui, en l’absence de récitatifs, expose la subjectivité du
personnage de Philippe de manière oblique par un réseau de renvois à l’art (grâce aux
références à Vélasquez et à Picasso), au folklore (par le rappel de la légende de la
chasse-galerie) et à l’influence des livres (à travers les romans d’aventures pour
adolescents). On a ainsi l’impression que, à rebours de l’employé de la télévision qui, au
début du récit, enjoint à son collègue de ne pas hésiter « à jouer la carte de l’histoire
vécue » (p. 16) en donnant la parole à l’une des victimes du prêtre pédophile, l’auteur a
refusé de s’engager à fond dans la veine autobiographique ; il semble avoir voulu employer
le témoignage simplement pour authentifier un matériel narratif dont la richesse et la
complexité font probablement de cet ouvrage la réalisation la plus achevée de Girard. C’est
à cet aspect de l’oeuvre que cet article s’intéresse.
A fast jaw‐tracking model for VMAT and IMRT Monte Carlo simulations
Authors: Townson Reid , Egglestone Hilary , Zavgorodni Sergei 
Published: May 2018

AbstractModern radiotherapy techniques involve routine use of volumetric arc therapy (VMAT) and intensity modulated radiotherapy (IMRT) with jaw‐tracking – dynamic motion of the secondary collimators (jaws) in tandem with multi‐leaf collimators (MLCs). These modalities require accurate dose calculations for the purposes of treatment planning and dose verification. Monte Carlo (MC) methods for radiotherapy dose calculation are widely accepted as capable of achieving high accuracy. This paper presents an efficiency‐enhancement method for secondary collimator modeling, presented in the context of a tool for MC‐based dose second checks. The model constitutes an accuracy trade‐off in the source model for the sake of efficiency enhancement, but maintains the advantages of MC transport in patient heterogeneities. The secondary collimator model is called Flat‐Absorbing‐Jaw‐Tracking (FAJT). Transmission through and scatter from the secondary collimators is neglected, and jaws are modeled as perfectly absorbing planes. To couple the motion of secondary collimators with MLCs for jaw‐tracking, the FAJT model was built into the VCU‐MLC model. Gamma‐index analysis of the dose distributions from FAJT against the full BEAMnrc MC simulations showed over 99% pass rate for a range of open fields, two clinical IMRT, and one VMAT treatment plan, for 2%/2 mm criteria above 10%. Using FAJT, the simulation speed of the secondary collimators for open fields increased by a factor of 237, 1489, and 1395 for 4 × 4, 10 × 10, and 30 × 30 cm2, respectively. In general, clinically oriented simulation times are reduced from “hours” to “minutes” on identical hardware. Results for nine representative clinical cases (seven with jaw‐tracking) are presented. The average 2%/2 mm γ‐test success rate above the 80% isodose was 96.8% when tested against the EPIDose electronic portal image‐based dose reconstruction method and 97.3% against the Eclipse analytical anisotropic algorithm.
Impact of Thickness on Contact Issues for Pinning Effect in Black Phosphorus Field‐Effect Transistors
Authors: Jiang Bei , Zou Xuming , Su Jie , Liang Jinghua , Wang Jingli , Liu Huijun , Feng Liping , Jiang Changzhong , Wang Feng , He Jun , Liao Lei 
Published: May 2018

AbstractMetal/semiconductor contact is a significant constraint in short‐channel field effect transistors (FETs) comprising black phosphorus (BP) and other 2D semiconductors. Due to the pinning effect at metal/2D semiconductor interface, the Schottky barrier usually does not follow the Schottky–Mott rule, resulting in thickness‐dependent FET performance. In this work, the Schottky barrier in BP FETs is investigated via theory calculation and electrical measurement. A simple metal/BP contact model is presented based upon thickness‐dependent electrical characteristics of BP FETs. The model considers the Schottky barrier as a combined effect of the Schottky–Mott rule and the pinning effect and provides a feasibility to track the conducting behavior of other 2D semiconductor FETs.