bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Structure of the Young Star Cluster NGC 6231. I. Stellar Population
Authors: Kuhn Michael A. , Medina Nicolás , Getman Konstantin V. , Feigelson Eric D. , Gromadzki Mariusz , Borissova Jordanka , Kurtev Radostin 
Published: August 2017

Abstract
NGC 6231 is a young cluster (age ∼2–7 Myr) dominating the Sco OB1 association (distance ∼1.59 kpc) with ∼100 O and B stars and a large pre-main-sequence stellar population. We combine a reanalysis of archival Chandra X-ray data with multiepoch near-infrared (NIR) photometry from the VISTA Variables in the Vía Lactéa (VVV) survey and published optical catalogs to obtain a catalog of 2148 probable cluster members. This catalog is 70% larger than previous censuses of probable cluster members in NGC 6231. It includes many low-mass stars detected in the NIR but not in the optical and some B stars without previously noted X-ray counterparts. In addition, we identify 295 NIR variables, about half of which are expected to be pre-main-sequence stars. With the more complete sample, we estimate a total population in the Chandra field of 5700–7500 cluster members down to 0.08

(assuming a universal initial mass function) with a completeness limit at 0.5

. A decrease in stellar X-ray luminosities is noted relative to other younger clusters. However, within the cluster, there is little variation in the distribution of X-ray luminosities for ages less than 5 Myr. The X-ray spectral hardness for B stars may be useful for distinguishing between early-B stars with X-rays generated in stellar winds and B-star systems with X-rays from a pre-main-sequence companion (>35% of B stars). A small fraction of catalog members have unusually high X-ray median energies or reddened NIR colors, which might be explained by absorption from thick or edge-on disks or being background field stars.
Supervised Learning Detection of Sixty Non-transiting Hot Jupiter Candidates
Authors: Millholland Sarah , Laughlin Gregory 
Published: August 2017

Abstract
The optical full-phase photometric variations of a short-period planet provide a unique view of the planet’s atmospheric composition and dynamics. The number of planets with optical phase curve detections, however, is currently too small to study them as an aggregate population, motivating an extension of the search to non-transiting planets. Here we present an algorithm for the detection of non-transiting short-period giant planets in the Kepler field. The procedure uses the phase curves themselves as evidence for the planets’ existence. We employ a supervised learning algorithm to recognize the salient time-dependent properties of synthetic phase curves; we then search for detections of signals that match these properties. After demonstrating the algorithm’s capabilities, we classify 142,630 FGK Kepler stars without confirmed planets or Kepler Objects of Interest, and for each one, we assign a probability of a phase curve of a non-transiting planet being present. We identify 60 high-probability non-transiting hot Jupiter candidates. We also derive constraints on the candidates’ albedos and offsets of the phase curve maxima. These targets are strong candidates for follow-up radial velocity confirmation and characterization. Once confirmed, the atmospheric information content in the phase curves may be studied in yet greater detail.
The SDSS-IV MaNGA Sample: Design, Optimization, and Usage Considerations
Authors: Wake David A. , Bundy Kevin , Diamond-Stanic Aleksandar M. , Yan Renbin , Blanton Michael R. , Bershady Matthew A. , Sánchez-Gallego José R. , Drory Niv , Jones Amy , Kauffmann Guinevere , Law David R. , Li Cheng , MacDonald Nicholas , Masters Karen , Thomas Daniel , Tinker Jeremy , Weijmans Anne-Marie , Brownstein Joel R. 
Published: August 2017

Abstract
We describe the sample design for the SDSS-IV MaNGA survey and present the final properties of the main samples along with important considerations for using these samples for science. Our target selection criteria were developed while simultaneously optimizing the size distribution of the MaNGA integral field units (IFUs), the IFU allocation strategy, and the target density to produce a survey defined in terms of maximizing signal-to-noise ratio, spatial resolution, and sample size. Our selection strategy makes use of redshift limits that only depend on i-band absolute magnitude (M

i
), or, for a small subset of our sample, M

i
and color (NUV − i). Such a strategy ensures that all galaxies span the same range in angular size irrespective of luminosity and are therefore covered evenly by the adopted range of IFU sizes. We define three samples: the Primary and Secondary samples are selected to have a flat number density with respect to M

i
and are targeted to have spectroscopic coverage to 1.5 and 2.5 effective radii (R

e
), respectively. The Color-Enhanced supplement increases the number of galaxies in the low-density regions of color–magnitude space by extending the redshift limits of the Primary sample in the appropriate color bins. The samples cover the stellar mass range

and are sampled at median physical resolutions of 1.37 and 2.5 kpc for the Primary and Secondary samples, respectively. We provide weights that will statistically correct for our luminosity and color-dependent selection function and IFU allocation strategy, thus correcting the observed sample to a volume-limited sample.
Absolute Magnitudes and Colors of RR Lyrae Stars in DECam Passbands from Photometry of the Globular Cluster M5
Authors: Vivas A. Katherina , Saha Abhijit , Olsen Knut , Blum Robert , Olszewski Edward W. , Claver Jennifer , Valdes Francisco , Axelrod Tim , Kaleida Catherine , Kunder Andrea , Narayan Gautham , Matheson Thomas , Walker Alistair 
Published: August 2017

Abstract
We characterize the absolute magnitudes and colors of RR Lyrae stars in the globular cluster M5 in the ugriz filter system of the Dark Energy Camera (DECam). We provide empirical period–luminosity (P–L) relationships in all five bands based on 47 RR Lyrae stars of the type ab and 14 stars of the type c. The P–L relationships were found to be better constrained for the fundamental-mode RR Lyrae stars in the riz passbands, with dispersions of 0.03, 0.02 and 0.02 mag, respectively. The dispersion of the color at minimum light was found to be small, supporting the use of this parameter as a means to obtain accurate interstellar extinctions along the line of sight up to the distance of the RR Lyrae star. We found a trend of color at minimum light with a pulsational period that, if taken into account, brings the dispersion in color at minimum light to

mag for the

,

, and

colors. These calibrations will be very useful for using RR Lyrae stars from DECam observations as both standard candles for distance determinations and color standards for reddening measurements.
Simultaneous Constraints on the Mass and Radius of Aql X–1 from Quiescence and X-Ray Burst Observations
Authors: Li Zhaosheng , Falanga Maurizio , Chen Li , Qu Jinlu , Xu Renxin 
Published: August 2017

Abstract
The measurement of neutron star mass and radius is one of the most direct ways to distinguish between various dense matter equations of state. The mass and radius of accreting neutron stars hosted in low-mass X-ray binaries can be constrained by several methods, including photospheric radius expansion from type I X-ray bursts and from quiescent spectra. In this paper, we apply for the first time these two methods simultaneously to constrain the mass and radius of Aql X–1. The quiescent spectra from Chandra and XMM-Newton, and photospheric radius expansion bursts from RXTE are used. The determination of the mass and radius of Aql X–1 is also used to verify the consistency between the two methods and to narrow down the uncertainties of the neutron star mass and radius. It is found that the distance to Aql X–1 should be in the range of 4.0–5.75 kpc, based on the overlapping confidence regions between photospheric radius expansion burst and quiescent spectra methods. In addition, we show that the mass and radius determined for the compact star in Aql X–1 are compatible with strange star equations of state and conventional neutron star models.
Three-dimensional Features of the Outer Heliosphere Due to Coupling between the Interstellar and Heliospheric Magnetic Field. V. The Bow Wave, Heliospheric Boundary Layer, Instabilities, and Magnetic Reconnection
Authors: Pogorelov N. V. , Heerikhuisen J. , Roytershteyn V. , Burlaga L. F. , Gurnett D. A. , Kurth W. S. 
Published: August 2017

Abstract
The heliosphere is formed due to interaction between the solar wind (SW) and local interstellar medium (LISM). The shape and position of the heliospheric boundary, the heliopause, in space depend on the parameters of interacting plasma flows. The interplay between the asymmetrizing effect of the interstellar magnetic field and charge exchange between ions and neutral atoms plays an important role in the SW–LISM interaction. By performing three-dimensional, MHD plasma/kinetic neutral atom simulations, we determine the width of the outer heliosheath—the LISM plasma region affected by the presence of the heliosphere—and analyze quantitatively the distributions in front of the heliopause. It is shown that charge exchange modifies the LISM plasma to such extent that the contribution of a shock transition to the total variation of plasma parameters becomes small even if the LISM velocity exceeds the fast magnetosonic speed in the unperturbed medium. By performing adaptive mesh refinement simulations, we show that a distinct boundary layer of decreased plasma density and enhanced magnetic field should be observed on the interstellar side of the heliopause. We show that this behavior is in agreement with the plasma oscillations of increasing frequency observed by the plasma wave instrument onboard Voyager 1. We also demonstrate that Voyager observations in the inner heliosheath between the heliospheric termination shock and the heliopause are consistent with dissipation of the heliospheric magnetic field. The choice of LISM parameters in this analysis is based on the simulations that fit observations of energetic neutral atoms performed by Interstellar Boundary Explorer.
Midterm Periodicity Analysis of the Mount Wilson Magnetic Indices Using the Synchrosqueezing Transform
Authors: Feng Song , Yu Lan , Wang Feng , Deng Hui , Yang Yunfei 
Published: August 2017

Abstract
A novel time–frequency technique, called the synchrosqueezing transform (SST), is used to investigate the midterm periodic variations of magnetic fields on the solar surface. The Magnetic Plage Strength Index (MPSI) and the Mount Wilson Sunspot Index (MWSI), measured daily by the Mount Wilson Observatory between 1970 January 19 and 2012 January 22, are selected. Short-, mid, and longer-term periodicities are represented and decomposed by the SST with hardly any mode mixing. This demonstrates that the SST is a useful time–frequency analysis technique to characterize the periodic modes of helioseismic data. Apart from the fundamental modes of the annual periodicity, ∼27 day rotational cycle and ∼11 year solar cycle, the SST reveals several midterm periodicities in the two magnetic activity indices, specifically, ∼157 days (i.e., Rieger-type periodicity), and ∼1.3 and 1.7 years. The periodic modes, with 116.4 and 276.2 day periodicity in the MPSI, 108.5 and 251.6 day periodicity in the MWSI, and 157.7 day periodicity in the two indices, are in better accord with those significant periodicities derived from the Rossby waves theoretical model. This study suggests that the modes are caused by Rossby waves. For the 1.30 and 1.71 year periodicity of the MPSI, and the 1.33 and 1.67 year periodicity of the MWSI, our analysis infers that they are related to those periodicities with the same timescale in the interior of the Sun and in the high atmospheric layers.
Reconnection–Condensation Model for Solar Prominence Formation
Authors: Kaneko Takafumi , Yokoyama Takaaki 
Published: August 2017

Abstract
We propose a reconnection–condensation model in which topological change in a coronal magnetic field via reconnection triggers radiative condensation, thereby resulting in prominence formation. Previous observational studies have suggested that reconnection at a polarity inversion line of a coronal arcade field creates a flux rope that can sustain a prominence; however, they did not explain the origin of cool dense plasmas of prominences. Using three-dimensional magnetohydrodynamic simulations, including anisotropic nonlinear thermal conduction and optically thin radiative cooling, we demonstrate that reconnection can lead not only to flux rope formation but also to radiative condensation under a certain condition. In our model, this condition is described by the Field length, which is defined as the scale length for thermal balance between radiative cooling and thermal conduction. This critical condition depends weakly on the artificial background heating. The extreme ultraviolet emissions synthesized with our simulation results have good agreement with observational signatures reported in previous studies.
Destruction of Refractory Carbon in Protoplanetary Disks
Authors: Anderson Dana E. , Bergin Edwin A. , Blake Geoffrey A. , Ciesla Fred J. , Visser Ruud , Lee Jeong-Eun 
Published: August 2017

Abstract
The Earth and other rocky bodies in the inner solar system contain significantly less carbon than the primordial materials that seeded their formation. These carbon-poor objects include the parent bodies of primitive meteorites, suggesting that at least one process responsible for solid-phase carbon depletion was active prior to the early stages of planet formation. Potential mechanisms include the erosion of carbonaceous materials by photons or atomic oxygen in the surface layers of the protoplanetary disk. Under photochemically generated favorable conditions, these reactions can deplete the near-surface abundance of carbon grains and polycyclic aromatic hydrocarbons by several orders of magnitude on short timescales relative to the lifetime of the disk out to radii of ∼20–100+ au from the central star depending on the form of refractory carbon present. Due to the reliance of destruction mechanisms on a high influx of photons, the extent of refractory carbon depletion is quite sensitive to the disk’s internal radiation field. Dust transport within the disk is required to affect the composition of the midplane. In our current model of a passive, constant-α disk, where α = 0.01, carbon grains can be turbulently lofted into the destructive surface layers and depleted out to radii of ∼3–10 au for 0.1–1 μm grains. Smaller grains can be cleared out of the planet-forming region completely. Destruction may be more effective in an actively accreting disk or when considering individual grain trajectories in non-idealized disks.
La Renault 14, une poire exemplaire
Authors: Marion Gilles 
Published: August 2017

L’histoire de la campagne publicitaire pour la Renault 14, réalisée en 1977 sur la France, fournit l’occasion d’examiner le rôle des études marketing dans le processus de création de la publicité au sein d’une entreprise du secteur automobile et de son agence au cours des années 1970. Elle permet aussi de mettre au jour les incertitudes sur les résultats obtenus et de montrer les limites du savoir des annonceurs et des agences de publicité sur les « effets » de la publicité. L’utilisation d’une métaphore controversée, “la poire”, donne un relief particulier à cette campagne. Une analyse sémantique de son contenu permet de repérer les interprétations probables d’une telle figure de rhétorique. Son retentissement et son écho durables dans le public et chez les journalistes permettent, enfin, de souligner les phénomènes de rumeurs qui transforment progressivement la “réalité” en un mythe contemporain.
L’hydropolitique environnementale du Mékong, entre intérêts nationaux et activisme international
Authors: Mottet Éric , Lasserre Frédéric 
Published: August 2017

Les enjeux environnementaux des aménagements hydroélectriques sur le cours principal du Mékong sont devenus un objet de débat important entre les pays riverains et les experts et activistes environnementaux, pour la plupart occidentaux. Sur le plan national, la question de la gestion très peu concertée des projets de barrages sur le cours principal du Mékong provoque bien dans la société civile une mobilisation, mais celle-ci ne débouche pas sur un fléchissement des politiques d’aménagement hydroélectrique. La faute en revient, d’une part, aux gouvernements qui, même sous pression, contrôlent sans partage la gestion des ressources du bassin et, d’autre part, à l’incapacité de la Commission du Mékong (MRC), malgré une légitimité institutionnelle, à développer un cadre juridique contraignant. Cela contribue à éroder progressivement la pertinence de la Commission aux yeux de ses membres, des bailleurs de fonds internationaux et de la Chine, qui propose désormais son propre modèle de coopération Sud-Sud, l’initiative de Coopération Lancang-Mékong (CLM).
Les barrages hydroélectriques amazoniens, un enjeu de géopolitique interne au Brésil
Authors: Broggio Céline , Droulers Martine , Pallamar Juan-Pablo 
Published: August 2017

Cet article développe une analyse géopolitique des barrages et usines hydroélectriques implantés en Amazonie brésilienne depuis le milieu des années 2000. La mise en œuvre de ces aménagements, en cristallisant de fortes tensions au sein du gouvernement fédéral alors sous présidence du Parti des travailleurs, a accéléré l’effritement de la plateforme idéologique et politique du « socioenvironnementalisme » et conduit à l’éclatement de la coalition gouvernementale, rendant possibles la crise politique de 2016 et l’éviction de la présidente Dilma Rousseff. Du point de vue régional, la contestation s’est manifestée sous des formes très différentes dans le cas des centrales hydroélectriques du Madeira (Santo Antônio et Jirau dans le Rondônia) et dans celui du barrage sur le Xingu (Belo Monte dans le Pará), fortement médiatisé au-delà même des frontières du Brésil.
Ressources et méthodes pour l’analyse diachronique
Authors: Diwersy Sascha , Falaise Achille , Lay Marie-Hélène , Souvay Gilles 
Published: August 2017

Du point de vue des corpus étiquetés du français, la période des xvi e - xviii e siècles fait figure de chaînon manquant. Les travaux que nous présentons ici s’attachent à combler ce manque. Cet article présente les difficultés de traitement que présentent les écrits français de cette période, le corpus diachronique que nous avons constitué, les choix techniques mis en œuvre pour son annotation, et enfin propose quelques méthodes statistiques pour son exploitation.
Les prépositions à et de et la complémentation verbale
Authors: Fagard Benjamin , Krawczak Karolina 
Published: August 2017

Dans cet article, nous étudions les constructions [ commencer/continuer à + infinitif] 1 et [ commencer/continuer de + infinitif] 2 , afin d’établir ce qui détermine le choix entre les deux. Nous analysons le pouvoir explicatif et prédictif de deux hypothèses, une hypothèse phonétique d’après laquelle l’emploi de la construction 2 serait lié à l’évitement du hiatus, et une hypothèse sémantique d’après laquelle l’emploi de la construction 1 serait favorisé en contexte télique. Nous le faisons à partir d’une large étude sur corpus en diachronie, mettant à profit, d’une part, les bases de textes disponibles (BFM, Frantext, Presto) , d’autre part, les outils lexicométriques et statistiques. Nos résultats confirment largement l’hypothèse phonétique, qui permet de rendre compte d’une large part de variation dans les données, et faiblement l’hypothèse sémantique, qui ne semble tenir que pour certaines périodes.
Les groupes prépositionnels avec conséquent/conseguente et conséquence/conseguenza et leur usage de connecteur. Une approche combinée quantitative et qualitative permet-elle de dégager des régularités ?
Authors: Rossari Corinne , Ricci Claudia 
Published: August 2017

Parmi les groupes prépositionnels formés en français et en italien avec conséquent / conseguente et conséquence / conseguenza , seulement certains ont des emplois de connecteur. Notre but est de cerner les facteurs en jeu dans l’émergence d’un emploi de connecteur pour un groupe prépositionnel. Une analyse quantitative des fréquences d’emploi de ces groupes nous permettra de voir s’il y a une relation entre la fréquence générale d’un groupe et son emploi en tant que connecteur et d’étudier le rôle de la préposition dans l’émergence de cet emploi. Une étude qualitative observera les environnements dans lesquels interviennent les groupes ayant un emploi de connecteur. Les deux analyses montrent que l’emploi de connecteur semble davantage issu de la dissémination du groupe dans une pluralité d’environnements (permise par l’augmentation de sa fréquence) que de la récurrence d’un de ses emplois dans une structure donnée.
A preliminary leaf epidermal and pollen morphology of some West African species of <i>Desplatsia</i> Bocq
Authors: Shokefun Emmanuel O. , Ayodele Abiodun E. , Orijemie Emuobosa A. 
Published: August 2017

Desplatsia is a genus made up of about four to eight species which are mostly trees native to tropical Africa. The leaf and pollen characters of three West African species of Desplatsia were investigated using light microscopy. The study was aimed at investigating the leaf epidermis and pollen morphology of the species to further enhance the understanding of the taxonomic relationships in the genus. The epidermal cells were isodiametric, polygonal to irregular with straight, curved to wavy anticlinal cell walls. The species were hypostomatic with anisocytic and staurocytic stomata types. The adaxial and abaxial walls of Desplatsia chrysochlamywere characterised by three-celled head multicellular glandular trichomes with highest number of cells and stomata and striated adaxial surface. The four-armed branched and stellate trichomes with the largest stomata size of 19.5 µm × 15.6 µm distinguished D. dewevrei from D. subericarpa in which the largest cells, lowest number of stomata and size were recorded. The pollen grains were medium in size 26.5 µm–47.5 µm, tricolporate with long colpi. However, the subprolate, baculate exine surface, small ora and lumen width separated D. chrysochlamy from D. dewevrei and D. subericarpa in which prolate, perforated exine surface and colpi margo were recorded. A key is provided for the identification of the species. Therefore, the ora size, lumen width, number of epidermal cell and stomata are additional taxonomic characters that can be used for species delimitation in the genus.
Relationship between verbal language and symbolic play - A case study
Authors: Segal Denise 
Published: August 2017

The linguistic ability and play of a language-impaired child were analysed to determine whether a breakdown in symbolic play occurs together with a language deficit. Observation of play was conducted at the child's nursery school (unstructured situation) and in a situation designed to elicit specific play behaviours (structured situation). Imaginative play and its concomitants — affect, mood variability, concentration, aggression and interaction — were rated along descriptive scales, while each individual play unit was scored for organization of behaviour. Syntactic, semantic and phonological aspects of language were recorded during free play and analyzed within a syntactic framework. The normal developmental sequence provided the baseline of comparison for both language and play. Results indicated a developmental lag in play and a linguistic deviation from the normal pattern, which supported the possibility of a general representational deficit. A method for incorporating symbolic play into a language programme was suggested and the necessity for normative studies in this area was stressed.