bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fabric transitions in plastically deformed quartzites : competition between basal, prism and rhomb systems
Authors: Lister Gordon Stuart 
Published: October 2018

On applique l'analyse de Taylor-Bishop-Hill pour la prédiction des orientations préférentielles du quartz, développées pendant la déformation plastique. De nombreuses possibilités de systèmes de glissement du quartz se trouvent dans la littérature. Ceci rend le problème d'autant plus difficile si l'on veut explorer, en simulation, toutes les possibilités. On a résolu ce problème en utilisant une nouvelle technique basée sur une exploration paramétrique le long de trajectoires dans un espace à n-dimensions.
Cette étude arrive à la conclusion qu'il existe de nombreux types d'orientations préférentielles. Les résultats vont dans le sens des idées de Fairbairn et Sander, selon lesquelles, par déformation plastique, les axes c du quartz se répartissent selon des orientations spécifiques et distinctes.
Global-mean Vertical Tracer Mixing in Planetary Atmospheres. I. Theory and Fast-rotating Planets
Authors: Zhang Xi , Showman Adam P. 
Published: October 2018

Abstract
Most chemistry and cloud formation models for planetary atmospheres adopt a one-dimensional (1D) diffusion approach to approximate the global-mean vertical tracer transport. The physical underpinning of the key parameter in this framework, eddy diffusivity K

zz
, is usually obscure. Here we analytically and numerically investigate vertical tracer transport in a 3D stratified atmosphere and predict K

zz
as a function of the large-scale circulation strength, horizontal mixing due to eddies and waves and local tracer sources and sinks. We find that K

zz
increases with tracer chemical lifetime and circulation strength but decreases with horizontal eddy mixing efficiency. We demarcated three K

zz
regimes in planetary atmospheres. In the first regime where the tracer lifetime is short compared with the transport timescale and horizontal tracer distribution under chemical equilibrium (

) is uniformly distributed across the globe, global-mean vertical tracer mixing behaves diffusively. But the traditional assumption in current 1D models that all chemical species are transported via the same eddy diffusivity generally breaks down. We show that different chemical species in a single atmosphere should in principle have different eddy diffusion profiles. In the second regime where the tracer is short-lived but

is non-uniformly distributed, a significant non-diffusive component might lead to a negative K

zz
under the diffusive assumption. In the third regime where the tracer is long-lived, global-mean vertical tracer transport is also largely influenced by non-diffusive effects. Numerical simulations of 2D tracer transport on fast-rotating zonally symmetric planets validate our analytical K

zz
theory over a wide parameter space.
Fermi-Large Area Telescope Observations of the Brightest Gamma-Ray Flare Ever Detected from CTA 102
Authors: Prince Raj , Raman Gayathri , Hahn Joachim , Gupta Nayantara , Majumdar Pratik 
Published: October 2018

Abstract
We present a multiwavelength study of the FSRQ CTA 102 using Fermi-LAT and simultaneous Swift-XRT/UVOT observations. The Fermi-LAT telescope detected one of the brightest flares from this object during 2016 September to 2017 March. In the 190 days of the observation period, the source underwent four major flares. A detailed analysis of the temporal and spectral properties of these flares indicates the flare at MJD 57751.594 has a γ-ray flux of (30.12 ± 4.48) × 10−6 ph cm−2 s−1 (from 90 minutes binning) in the energy range of 0.1–300 GeV. This has been found to be the highest flux ever detected from CTA 102. Time dependent leptonic modeling of the preflare, rising state, flares and decaying state has been done. A single emission region of size 6.5 × 1016 cm has been used in our work to explain the multiwavelength spectral energy distributions. During flares, the luminosity in electrons increases nearly seventy times compared to the preflare state.
Multicolor Blackbody Emission in GRB 081221
Authors: Hou Shu-Jin , Zhang Bin-Bin , Meng Yan-Zhi , Wu Xue-Feng , Liang En-Wei , Lü Hou-Jun , Liu Tong , Liang Yun-Feng , Lin Lin , Lu Rui-jing , Huang Jin-Shu , Zhang Bing 
Published: October 2018

Abstract
The radiation mechanism of the prompt emission of gamma-ray bursts (GRBs) remains an open question. Although their spectra are usually well fitted with the empirical Band function, which is widely believed to be fully nonthermal and interpreted as an optically thin synchrotron emission, accumulating evidence shows that a thermal component actually exists. In this paper, a multicolor blackbody (mBB) model is proposed for the time-integrated spectrum of GRB 081221 by assuming a power-law distribution of the thermal luminosities with temperature, which manifests photospheric emissions from a different radius and/or angle. The effects of the minimum temperature kT
min, the maximum temperature kT
max, and the power-law index m of the luminosity distribution of an mBB are discussed. The fitting to the time-integrated spectrum during the bright phase (from 20 to 30 s since the trigger) of GRB 081221 by the mBB model yields kT
min = 4.4 ± 0.3 keV,

, and

. When the time bin is small enough, the time-resolved spectra of GRB 081221 are well fitted with a series of single-temperature blackbodies. Our results imply the prompt emission of GRB 081221 is dominated by the photosphere emission and its time-integrated spectrum is a superposition of pure blackbody components at different times, indicating that some empirical Band spectra may be interpreted as mBB if the temperature is widely distributed.
Confirmation of a New Metal-poor Globular Cluster in the Galactic Bulge∗
Authors: Minniti Dante , Schlafly E. F. , Palma Tali , Clariá Juan J. , Hempel Maren , Alonso-García Javier , Bica Eduardo , Bonatto Charles , Braga Vittorio F. , Clementini Gisella , Garofalo Alessia , Gómez Matías , Ivanov Valentin D. , Lucas Phillip W. , Pullen Joyce , Saito Roberto K. , Smith Leigh C. 
Published: October 2018

Abstract
We use deep near-IR photometry of the VISTA Variables in the Vía Láctea (VVV) Survey and deep DECam Plane Survey (DECaPS) optical photometry to confirm the physical reality of the candidate globular cluster (GC) Minni 22, which is located in the Galactic bulge. This object, which was detected as a high density region in our maps of bulge red giants, is now confirmed as a real GC based on the optical and near-IR color–magnitude diagrams. We also recover three known fundamental mode (ab type) RR Lyrae stars within 2 arcmin of the cluster center. The presence of RR Lyrae stars also seems to confirm Minni 22 as a bonafide old and metal-poor GC. We estimate a cluster reddening

mag and determine its heliocentric distance D = 7.4 ± 0.3 kpc. The optical and near-IR color–magnitude diagrams reveal well-defined red giant branches in all cases, including a red giant branch bump at Ks = 13.30 ± 0.05 mag. The comparison with theoretical isochrones yields a mean metallicity of [Fe/H] = −1.3 ± 0.3 dex, and age of t ∼ 11.2 Gyr. This is a good example of a new low-luminosity (M

V
= −6.2 mag) GC found in the central bulge of the Milky Way. After discussing the different ways to confirm the existence of bulge GC candidates, we find that one of the best methods is to use the CMDs from the combination of the DECaPS + VVV photometries.
Authenticating the Presence of a Relativistic Massive Black Hole Binary in OJ 287 Using Its General Relativity Centenary Flare: Improved Orbital Parameters
Authors: Dey Lankeswar , Valtonen M. J. , Gopakumar A. , Zola S. , Hudec R. , Pihajoki P. , Ciprini S. , Matsumoto K. , Sadakane K. , Kidger M. , Nilsson K. , Mikkola S. , Sillanpää A. , Takalo L. O. , Lehto H. J. , Berdyugin A. , Piirola V. , Jermak H. , Baliyan K. S. , Pursimo T. , Caton D. B. , Alicavus F. , Baransky A. , Blay P. , Boumis P. , Boyd D. , Torrent M. Campas , Campos F. , Gómez J. Carrillo , Chandra S. , Chavushyan V. , Dalessio J. , Debski B. , Drozdz M. , Er H. , Erdem A. , Pérez A. Escartin , Ramazani V. Fallah , Filippenko A. V. , Gafton E. , Ganesh S. , Garcia F. , Gazeas K. , Godunova V. , Pinilla F. Gómez , Gopinathan M. , Haislip J. B. , Harmanen J. , Hurst G. , Janík J. , Jelinek M. , Joshi A. , Kagitani M. , Karjalainen R. , Kaur N. , Keel W. C. , Kouprianov V. V. , Kundera T. , Kurowski S. , Kvammen A. , LaCluyze A. P. , Lee B. C. , Liakos A. , Lindfors E. , de Haro J. Lozano , Mugrauer M. , Nogues R. Naves , Neely A. W. , Nelson R. H. , Ogloza W. , Okano S. , Pajdosz-Śmierciak U. , Pandey J. C. , Perri M. , Poyner G. , Provencal J. , Raj A. , Reichart D. E. , Reinthal R. , Reynolds T. , Saario J. , Sadegi S. , Sakanoi T. , González J.-L. Salto , Sameer  , Schweyer T. , Simon A. , Siwak M. , Alfaro F. C. Soldán , Sonbas E. , Steele I. , Stocke J. T. , Strobl J. , Tomov T. , Espasa L. Tremosa , Valdes J. R. , Pérez J. Valero , Verrecchia F. , Vasylenko V. , Webb J. R. , Yoneda M. , Zejmo M. , Zheng W. , Zielinski P. 
Published: October 2018

Abstract
Results from regular monitoring of relativistic compact binaries like PSR 1913+16 are consistent with the dominant (quadrupole) order emission of gravitational waves (GWs). We show that observations associated with the binary black hole (BBH) central engine of blazar OJ 287 demand the inclusion of gravitational radiation reaction effects beyond the quadrupolar order. It turns out that even the effects of certain hereditary contributions to GW emission are required to predict impact flare timings of OJ 287. We develop an approach that incorporates this effect into the BBH model for OJ 287. This allows us to demonstrate an excellent agreement between the observed impact flare timings and those predicted from ten orbital cycles of the BBH central engine model. The deduced rate of orbital period decay is nine orders of magnitude higher than the observed rate in PSR 1913+16, demonstrating again the relativistic nature of OJ 287's central engine. Finally, we argue that precise timing of the predicted 2019 impact flare should allow a test of the celebrated black hole “no-hair theorem” at the 10% level.
Late-time Observations of ASASSN-14lp Strengthen the Case for a Correlation between the Peak Luminosity of Type Ia Supernovae and the Shape of Their Late-time Light Curves
Authors: Graur Or , Zurek David R. , Cara Mihai , Rest Armin , Seitenzahl Ivo R. , Shappee Benjamin J. , Shara Michael M. , Riess Adam G. 
Published: October 2018

Abstract
Late-time observations of Type Ia supernovae (SNe Ia), >900 days after explosion, have shown that this type of SN does not suffer an “IR catastrophe” at 500 days as previously predicted. Instead, several groups have observed a slow-down in the optical light curves of these SNe. A few reasons have been suggested for this slow-down, from a changing fraction of positrons reprocessed by the expanding ejecta, through a boost of energy from slow radioactive decay chains such as 57Co→57Fe, to atomic “freeze-out.” Discovering which of these (or some other) heating mechanisms is behind the slow-down will directly impact studies of SN Ia progenitors, explosion models, and nebular-stage physics. Recently, Graur et al. suggested a possible correlation between the shape of the late-time light curves of four SNe Ia and their stretch values, which are proxies for their intrinsic luminosities. Here, we present Hubble Space Telescope observations of the SN Ia ASASSN-14lp at ∼850–960 days past maximum light. With a stretch of s = 1.15 ± 0.05, it is the most luminous normal SN Ia observed so far at these late times. We rule out contamination by light echoes and show that the late-time, optical light curve of ASASSN-14lp is flatter than that of previous SNe Ia observed at late times. This result is in line with—and strengthens—the Graur et al. correlation, but additional observations of SNe are needed to verify it.
The z = 0.54 LoBAL Quasar SDSS J085053.12+445122.5. I. Spectral Synthesis Analysis Reveals a Massive Outflow∗
Authors: Leighly Karen M. , Terndrup Donald M. , Gallagher Sarah C. , Richards Gordon T. , Dietrich Matthias 
Published: October 2018

Abstract
We introduce SimBAL, a novel spectral-synthesis procedure that uses grids of ionic column densities generated by the photoionization code Cloudy and a Bayesian model calibration to forward-model broad absorption-line quasar (BALQ) spectra. We used SimBAL to analyze the Hubble Space Telescope Cosmic Origins Spectrograph (COS) spectrum of the low-redshift BALQ SDSS J085053.12+445122.5. SimBAL analysis yielded velocity-resolved information about the physical conditions of the absorbing gas. We found that the ionization parameter and column density increase, and the covering fraction decreases, as a function of velocity. The log column density is 22.9 (22.4) (cm−2) for solar (Z = 3 Z
⊙) metallicity. The outflow lies 1–3 pc from the central engine, consistent with the estimated location of the torus. The mass outflow rate is 17–28 M
⊙ yr−1, the momentum flux is consistent with L
Bol/c, and the ratio of the kinematic to bolometric luminosity is 0.8%–0.9%. The outflow velocity is similar to the escape velocity at the absorber’s location, and force multiplier analysis indicates that part of the outflow could originate in resonance-line driving. The location near the torus suggests that dust scattering may play a role in the acceleration, although the lack of reddening in this UV-selected object indicates a relatively dust-free line of sight. The low accretion rate (0.06L
Edd) and compact outflow suggests that SDSS J0850+4451 might be a quasar past its era of feedback, although since its mass outflow is about eight times the accretion rate, the wind is likely integral to the accretion physics of the central engine.
Sound Speed Dependence of Alignment in Accretion Disks Subjected to Lense–Thirring Torques
Authors: Hawley John F. , Krolik Julian H. 
Published: October 2018

Abstract
We present a series of simulations in both pure hydrodynamics (HD) and magnetohydrodynamics (MHD) exploring the degree to which alignment of disks subjected to external precessional torques (e.g., as in the “Bardeen–Petterson” effect) is dependent upon the disk sound speed c

s
. Across the range of sound speeds examined, we find that the influence of the sound speed can be encapsulated in a simple “lumped-parameter” model proposed by Sorathia et al. In this model, alignment fronts propagate outward at a speed ≃0.2rΩprecess(r), where Ωprecess is the local test-particle precession frequency. Meanwhile, transonic radial motions transport angular momentum both inward and outward at a rate that can, in steady-state, be described roughly in terms of an orientation diffusion model with diffusion coefficient

, for local orbital frequency Ω. The competition between the two leads, in isothermal disks, to a stationary position for the alignment front at a radius

. For alignment to happen at all, the disk must either be turbulent due to the magnetorotational instability in MHD, or, in HD, it must be cool enough for the bending waves driven by disk warp to be nonlinear at their launch point. Contrary to long-standing predictions, warp dynamics in MHD disks appears to be independent of the ratio c

s
/(αv
orb), for orbital speed v
orb and ratio of stress to pressure α. In purely HD disks, i.e., those with no internal stresses other than bulk viscosity, warmer disks align weakly or not at all; cooler disks align qualitatively similarly to MHD disks.
Large-scale Compression Acceleration during Magnetic Reconnection in a Low-β Plasma
Authors: Li Xiaocan , Guo Fan , Li Hui , Li Shengtai 
Published: October 2018

Abstract
In solar flares and other astrophysical systems, a major challenge for solving the particle acceleration problem associated with magnetic reconnection is the enormous scale separation between kinetic scales and the observed reconnection scale. Because of this, it has been difficult to draw any definite conclusions by just using kinetic simulations. A particle acceleration model that solves the energetic particle transport equation can capture the main acceleration physics found in kinetic simulations and thus provide a practical way to make observable predictions and directly compare model results with observations. Here we study compression particle acceleration in magnetic reconnection by solving the Parker (diffusion–advection) transport equation using velocity and magnetic fields from two-dimensional magnetohydrodynamics (MHD) simulations of a low-β high-Lundquist-number reconnection layer. We show that the compressible reconnection layer can give significant particle acceleration, leading to the formation of power-law particle energy distributions. We analyze the acceleration rate and find that the acceleration in the reconnection layer is a mixture of first- and second-order Fermi processes. When including a guide field, we find that the spectrum becomes steeper and both the power-law cutoff energy and maximum particle energy decrease as plasma becomes less compressible. This model produces a 2D particle distribution that one can use to generate a radiation map and directly compare with solar flare observations. This provides a framework to explain particle acceleration at large-scale astrophysical reconnection sites, such as solar flares.
Jet Dynamics in Compact Object Mergers: GW170817 Likely Had a Successful Jet
Authors: Duffell Paul C. , Quataert Eliot , Kasen Daniel , Klion Hannah 
Published: October 2018

Abstract
We use relativistic hydrodynamic numerical calculations to study the interaction between a jet and a homologous outflow produced dynamically during binary neutron star mergers. We quantify how the thermal energy imparted by the jet and the ability of the jet to escape the ejecta depend on the parameters of the jet engine and the ejecta. Under our assumptions, a collimated jet initiated at early times compared to the engine duration, we show that successful breakout of the forward cocoon shock necessitates a jet that successfully escapes the ejecta. This is because the ejecta is expanding, and the forward shock from a failed jet stalls before it reaches the edge of the ejecta. This conclusion can be circumvented only for very energetic wide angle jets, with parameters that are uncomfortable given short-duration GRB observations. For successful jets, we find two regimes of jet breakout from the ejecta: early breakout on timescales shorter than the engine duration, and late breakout well after the engine shuts off. A late breakout can explain the observed delay between gravitational waves and gamma rays in GW170817. We show that for the entire parameter space of jet parameters surveyed here (covering energies ∼1048–1051 erg and opening angles θ

j
∼ 0.07–0.4) the thermal energy deposited by the jet is less than that produced by r-process heating on second timescales by at least an order of magnitude. Shock heating is thus energetically subdominant in setting the luminosity of thermally powered transients coincident with neutron star mergers (kilonovae).
Diversité des politiques d’adoption des IFRS : l’harmonisation financière est-elle possible ?
Authors: de Brébisson Hélène , Alphonse Pascal 
Published: October 2018

Les IFRS ont été adoptées à travers le monde selon des politiques variées d’application optionnelle, obligatoire, restreinte ou générale : nous proposons une typologie des politiques d’adoption des normes internationales. Nous modélisons le choix de ces politiques en fonction des caractéristiques économiques et institutionnelles des pays à l’aide d’un logit multinomial non ordonné. Les résultats suggèrent des choix durables, déterminés notamment par des caractéristiques stables des pays. Cette situation réglementaire diversifiée peut expliquer l’hétérogénéité des pratiques des IFRS.
Governance effectiveness and earnings quality: Evidence from microfinance institutions
Authors: Tchakoute Tchuigoua Hubert 
Published: October 2018

Existe-t-il une relation entre l’efficacité de la gouvernance et la gestion des résultats dans les institutions de microfinance? Telle est la question à laquelle cet article tente de répondre. Nous étudions un échantillon composé de 345 rapports de rating de 2001 à 2011 pour 253 IMF et utilisons deux mesures de gestion des résultats: un mesure fondée sur les accruals discrétionnaires et une mesure fondée sur la fréquence des profits faibles. Nous trouvons un effet significatif de l’efficacité de la gouvernance sur la gestion des résultats. Une bonne qualité de gouvernance limite le pouvoir discrétionnaire qu’ont les managers dans la détermination du montant des provisions enregistrées sur les créances en retard dans les organisations hybrides tels que les institutions de microfinance. De plus, un système de gouvernance perçu comme efficace limite la probabilité que les IMF reportent de petits profits.
Quels processus pour répondre aux besoins spécifiques des entrepreneures ?
Authors: Santoni Juliane 
Published: October 2018

Malgré un intérêt croissant pour les pratiques d’accompagnement, peu de travaux portent aujourd’hui sur l’accompagnement des entrepreneures. Il est souvent observé pourtant que les dispositifs mis en place ne correspondent pas à leurs besoins ni à leurs attentes. Nous proposons ici de mieux comprendre les besoins d’accompagnement des entrepreneures. Les résultats sont issus d’une recherche qualitative de près de trois ans réalisée auprès de différents acteurs : porteurs et porteuses de projets, entrepreneur.e.s, acteurs de l’accompagnement et acteurs institutionnels. Ces travaux montrent l’importance de l’adéquation entre la forme d’accompagnement (formation conseil, mentorat, peer-coaching ou coaching) et la nature du besoin identifié chez les entrepreneures
Une Boussole pour les futures licornes
Authors: Verzat Caroline , Lesage Xavier , Tordo Maeva , Jeannest Paul 
Published: October 2018

La Boussole 1 est un partenariat entre dix structures d’accompagnement privées (50 Partners, Blue Factory – Escp Europe, Google, INCO, Le Village by CA, Numa, RAISE Sherpas, Réseau Entreprendre Paris, Schoolab et UR Link-Unibail Rodamco) visant à structurer l’écosystème d’accompagnement pour aider les jeunes entreprises françaises à devenir des licornes. La première étape du partenariat prend la forme d’un guide des meilleures pratiques réalisé avec le Boston Consulting Group à destination des entrepreneurs et des accompagnateurs. L’entretien avec deux membres de La Boussole, Maëva Tordo, responsable de l’incubateur Blue Factory-ESCP Europe et Paul Jeannest, directeur de RaiseSherpas, explique l’origine de cette initiative, son fonctionnement sous le mode d’un réseau d’échanges, mais aussi ses visées de structuration de l’écosystème et la démarche de nature effectuale qu’elle adopte pour se développer. La philosophie d’accompagnement à but de croissance est décrite en parallèle.
L’étudiant entrepreneur : un agité du bocal ?
Authors: Jacquemin Amélie , Lesage Xavier 
Published: October 2018

Sollicités pour rendre compte d’un atelier sur l’accompagnement des étudiants entrepreneurs qui s’est tenu en janvier 2018, nous en évoquons sa forme iconoclaste, d’une part du fait de la méthodologie d’animation employée et d’autre part du fait de la richesse spontanée des échanges que celle-ci a permis. La méthodologie collaborative utilisée, celle dite du « fishbowl » a permis une discussion se structurant d’elle même malgré le nombre élevé de participants, au rythme des mouvements de participants jouant tantôt aux « poissons » autorisés à prendre la parole au centre du local-bocal, tantôt au « public » silencieux et observateur resté au bord du bocal. Sur le fond, nous soulignons les points de divergence entre étudiants entrepreneurs, professionnels de l’accompagnement et professeurs d’entrepreneuriat qui émaillent la représentation que chacun d’eux se fait d’un accompagnement idéal.