bluuebunny/crossref_metadata_2025_split huggingface dataset:
العلاقة السببية بين أسعار السكر وزيت زهرة الشمس المستورد وأسعار النفط الخام وسعر الصرف للدينار العراقي
Authors: العبدلي سعد عبد نجم , سليمان هيفاء يوسف 
Published: February 2019

يتزامن ارتفاع إسعار بعض المحاصيل الزراعية المتاجر بها في الاسواق العالمية مع ارتفاع اسعار النفط الخام في السوق العالمي منذ بداية القرن 21 مما يؤشر امكانية احتمال وجود علاقة سببية مباشرة وغير مباشرة قصيرة الاجل وطويلة الاجل بين اسعار هذه المتغيرات الاقتصادية. هدفت الدراسة الى تحليل العلاقة السببية المباشرة وغير المباشرة قصيرة الاجل وطويلة الاجل بين كل من اسعار النفط الخام العراقي المصدر للعالم وسعر الصرف للدينار العراقي مقابل الدولار الامريكي واسعار محصولين مهمين يستوردها العراق وهي السكر والزيوت النباتية متمثلة بأسعار زيت زهرة الشمس بهدف وضع السياسة السعرية الاستيرادية والتصديرية المناسبة التي تدعم الاقتصاد العراقي كونه اقتصادا ريعيا يعتمد على ايرادات النفط كليا ضمن الفترة 2004:1 - 2016:4 وعلى اساس فصلي. وقد اشارت النتائج الى ان اسعار النفط الخام وتذبذبها يؤشر بشكل مباشر وغير مباشر على اسعار هذه المحاصيل الزراعية المستوردة في العراق بشكل او بأخر حيث توجد علاقة سببية مباشرة تتجه من اسعار النفط الخام الى اسعار زيت زهرة الشمس لفترة تباطئ زمنية واحدة او أكثر في كثير من الحالات بمعنى ان اسعار النفط الخام لها تأثير ايجابي ومعنوي احصائيا على اسعار المحاصيل الزراعية المستوردة هذه في حين لم تكن هناك تأثير معنوي لأسعار النفط الخام على اسعار السكر المستورد في العراق.
The so-called relation forms of nouns in South Saami
Authors: Ylikoski Jussi 
Published: February 2019

The paper describes a previously little-known grammatical category in South Saami. Termed here as “relation forms”, the phenomenon in question is etymologically related to the comparative and superlative marking of adjectives, but synchronically quite distinct from it. The suffix -be/-åbpoe can be attached to not only adjectives (e.g., nuerebe ‘younger’, båarasåbpoe ‘older’), but also to nouns and kinship terms in particular (e.g., tjidtjebe ‘(the) mother’, vuanavåbpoe ‘(the) mother-in-law’), and the superlative marker -mes/-ommes can be used similarly, albeit to a lesser extent. The paper discusses the position of such forms in South Saami morphology, syntax and sentential semantics, especially in relation to markers of definiteness and possession. From a diachronic perspective, South Saami sheds new light on the origin of the Saami-Finnic (and Hungarian) comparative marker *-mpV, and from a typological point of view, it is proposed that the closest analogues to the Saami phenomenon can be found in Tungusic, which also adds to our understanding of the development of *-mpV comparatives – possibly from a more original contrastive function of the suffix.
Pitch-angle Diffusion and Bohm-type Approximations in Diffusive Shock Acceleration
Authors: Riordan John Daniel , Pe’er Asaf 
Published: February 2019

Abstract
The problem of accelerating cosmic rays is one of fundamental importance, particularly given the uncertainty in the conditions inside the acceleration sites. Here we examine diffusive shock acceleration in arbitrary turbulent magnetic fields, constructing a new model that is capable of bridging the gap between the very weak (δB/B
0 ≪ 1) and the strong turbulence regimes. To describe the diffusion we provide a quantitative analytical description of the “Bohm exponent” in each regime. We show that our results converge to the well known quasi-linear theory in the weak turbulence regime. In the strong regime, we quantify the limitations of the Bohm-type models. Furthermore, our results account for the anomalous diffusive behavior which has been noted previously. Finally, we discuss the implications of our model in the study of possible acceleration sites in different astronomical objects.
Jet-powered Outflows in Supermassive Black Hole Binary Candidate SDSS J1048+0055
Authors: Jaiswal Sumit , Mohan Prashanth , An Tao , Frey Sándor 
Published: February 2019

Abstract
The search and study of close pairs of supermassive black holes (SMBHs) is important in the study of galaxy mergers that can possibly trigger active galactic nucleus (AGN) activity, and in the context of their evolution into the gravitational wave emitting regime. The quasar SDSS J1048+0055 was identified as an SMBH binary (SMBHB) candidate based on the observed double-peaked [O iii] λλ4959, 5007 emission lines and two distinct radio components separated by ∼20 pc (Zhou et al. 2004). To ascertain the binary nature of this source, we analyzed multifrequency, multiepoch very long baseline interferometry (VLBI) data to investigate its parsec-scale radio properties. The source shows double components with the western feature being brighter than the eastern one. This brighter component has a brightness temperature of ∼1010 K, a spectral index of α = −0.09 ± 0.09 (flat), and is indicative of mildly relativistic beaming. In contrast, the faint component has a lower brightness temperature of ∼108−9 K and a steep spectrum. These clues are consistent with a core–jet structure; moreover, the apparent separation speed between the two components is much higher than the expected orbital motion in a binary SMBH. Thus the present study excludes the association of the two VLBI components with the cores of an SMBHB; though, the SMBHB possibility (e.g., a pair of radio-loud and radio-quiet AGNs) is not fully ruled out. In the single AGN scenario, the double-peaked optical emission lines can originate from the jet interacting with the narrow-line region as indicated by a change in the jet direction at ∼140 pc.
The Galactic Center: Improved Relative Astrometry for Velocities, Accelerations, and Orbits near the Supermassive Black Hole
Authors: Jia Siyao , Lu Jessica R. , Sakai S. , Gautam A. K. , Do T. , Hosek M. W. , Service M. , Ghez A. M. , Gallego-Cano E. , Schödel R. , Hees Aurelien , Morris M. R. , Becklin E. , Matthews K. 
Published: February 2019

Abstract
We present improved relative astrometry for stars within the central half parsec of our Galactic Center (GC) based on data obtained with the 10 m W. M. Keck Observatory from 1995 to 2017. The new methods used to improve the astrometric precision and accuracy include correcting for local astrometric distortions, applying a magnitude-dependent additive error, and more carefully removing instances of stellar confusion. Additionally, we adopt jackknife methods to calculate velocity and acceleration uncertainties. The resulting median proper motion uncertainty is 0.05 mas yr−1 for our complete sample of 1184 stars in the central 10″ (0.4 pc). We have detected 24 accelerating sources, 2.6 times more than the number of previously published accelerating sources, which extend out to 4″ (0.16 pc) from the black hole. Based on S0-2's orbit, our new astrometric analysis has reduced the systematic error of the supermassive black hole (SMBH) by a factor of 2. The linear drift in our astrometric reference frame is also reduced in the north–south direction by a factor of 4. We also find the first potential astrometric binary candidate S0-27 in the GC. These astrometric improvements provide a foundation for future studies of the origin and dynamics of the young stars around the SMBH, the structure and dynamics of the old nuclear star cluster, the SMBH’s properties derived from orbits, and tests of general relativity in a strong gravitational field.
Influence of Stellar Metallicity on Occurrence Rates of Planets and Planetary Systems
Authors: Zhu 祝 Wei 伟 
Published: February 2019

Abstract
We study the influence of stellar metallicity on the fraction of stars with planets (i.e., the occurrence rate of planetary systems) and the average number of planets per star (i.e., the occurrence rate of planets). The former directly reveals the planet formation efficiency, whereas the latter reveals the final product of formation and evolution. We show that these two occurrence rates have different dependences on stellar metallicity. Specifically, the fraction of stars with planets rises gradually with metallicity, from ∼25% to ∼36% for 0.4 dex of [Fe/H] for all Kepler-like planets (period P < 400 days and radius

). The average number of planets per star reaches a plateau (or possibly starts declining) at [Fe/H] ≳ 0.1. This is plausibly caused by the emergence of distant giant planets at high metallicities, given that the close-in small planets and the distant giants preferentially coexist in the same system.
The Early Stage of Molecular Cloud Formation by Compression of Two-phase Atomic Gases
Authors: Iwasaki Kazunari , Tomida Kengo , Inoue Tsuyoshi , Inutsuka Shu-ichiro 
Published: February 2019

Abstract
We investigate the formation of molecular clouds from atomic gas by using three-dimensional magnetohydrodynamic simulations, including non-equilibrium chemical reactions and heating/cooling processes. We consider super-Alfvénic head-on colliding flows of atomic gas possessing the two-phase structure that consists of H i clouds and surrounding warm diffuse gas. We examine how the formation of molecular clouds depends on the angle θ between the upstream flow and the mean magnetic field. We find that there is a critical angle θ
cr above which the shock-amplified magnetic field controls the post-shock gas dynamics. If the atomic gas is compressed almost along the mean magnetic field (θ ≪ θ
cr), super-Alfvénic anisotropic turbulence is maintained by the accretion of the highly inhomogeneous upstream atomic gas. As a result, a greatly extended turbulence-dominated post-shock layer is generated. Around θ ∼ θ
cr, the shock-amplified magnetic field weakens the post-shock turbulence, leading to a dense post-shock layer. For θ ≫ θ
cr, the strong magnetic pressure suppresses the formation of cold dense clouds. Efficient molecular cloud formation is expected if θ is less than a few times θ
cr. Developing an analytic model and performing a parameter survey, we obtain an analytic formula for the critical angle as a function of the mean density, collision speed, and field strength of the upstream atomic gas. The critical angle is found to be less than ∼15° as long as the field strength is larger than 1 μG, indicating that the probability of occurrence of compression with θ < θ
cr is limited if shock waves come from various directions.
Calibrating Star Formation Rate Prescriptions at Different Scales (10 pc–1 kpc) in M31
Authors: Tomičić Neven , Ho I-Ting , Kreckel Kathryn , Schinnerer Eva , Leroy Adam , Groves Brent , Sandstrom Karin , Blanc Guillermo A. , Jarrett Thomas , Thilker David , Kapala Maria , McElroy Rebecca 
Published: February 2019

Abstract
We calibrate commonly used star formation rate (SFR) prescriptions using observations in five kiloparsec-sized fields in the nearby galaxy Andromeda (M31) at 10 pc spatial resolution. Our observations at different scales enable us to resolve the star-forming regions and to distinguish them from non-star-forming components. We use extinction-corrected Hα from optical integral field spectroscopy as our reference tracer and have verified its reliability via tests. It is used to calibrate monochromatic and hybrid (Hα+a×IR and far-UV+b×IR) SFR prescriptions, which use far-UV (GALEX), 22 μm (Wide-field Infrared Survey Explorer), and 24 μm (MIPS). Additionally, we evaluate other multiwavelength infrared tracers. Our results indicate that the SFR prescriptions do not change (in M31) with spatial scales or with subtraction of the diffuse component. For the calibration factors in the hybrid SFR prescriptions, we find a ≈ 0.2 and b ≈ 22 in M31, which are a factor of 5 higher than in the literature. As the fields in M31 exhibit high attenuation and low dust temperatures, lie at large galactocentric distances, and suffer from high galactic inclination compared to measurements in other galaxies, we propose that the fields probe a dust layer extended along the line of sight that is not directly spatially associated with star-forming regions. This (vertically) extended dust component increases the attenuation and alters the SFR prescriptions in M31 compared to literature measurements. We recommend that SFR prescriptions should be applied with caution at large galactocentric distances and in highly inclined galaxies, due to variations in the relative (vertical) distribution of dust and gas.
Electron and Proton Heating in Transrelativistic Guide Field Reconnection
Authors: Rowan Michael E. , Sironi Lorenzo , Narayan Ramesh 
Published: February 2019

Abstract
The plasma in low-luminosity accretion flows, such as the one around the black hole at the center of M87 or Sgr A* at our Galactic Center, is expected to be collisioness and of two temperatures, with protons hotter than electrons. Here, particle heating is expected to be controlled by magnetic reconnection in the transrelativistic regime

, where the magnetization

is the ratio of magnetic energy density to plasma enthalpy density. Using large-scale 2D particle-in-cell simulations, we explore for a fiducial

how the dissipated magnetic energy is partitioned between electrons and protons as a function of

(the ratio of proton thermal pressure to magnetic pressure) and of the strength of a guide field

perpendicular to the reversing field B
0. At low

, we find that the fraction of initial magnetic energy per particle converted into electron irreversible heat is nearly independent of

, whereas protons are heated much less with increasing

. As a result, for large

, electrons receive the overwhelming majority of irreversible particle heating (∼93% for

). This is significantly different than the antiparallel case

, in which irreversible electron heating accounts for only ∼18% of the total particle heating (Rowan et al. 2017). At

, when both species start already relativistically hot (for our fiducial

), electrons and protons each receive ∼50% of the irreversible particle heating, regardless of the guide field strength. Our results provide important insights into the plasma physics of electron and proton heating in hot accretion flows around supermassive black holes.
Origin of Radio-quiet Coronal Mass Ejections in Flare Stars
Authors: Mullan D. J. , Paudel R. R. 
Published: February 2019

Abstract
Type II radio bursts are observed in the Sun in association with many coronal mass ejections (CMEs). In view of this association, there has been an expectation that, by scaling from solar flares to the flares that are observed on M dwarfs, radio emission analogous to solar type II bursts should be detectable in association with M dwarf flares. However, several surveys have revealed that this expectation does not seem to be fulfilled. Here we hypothesize that the presence of larger global field strengths in low-mass stars, suggested by recent magnetoconvective modeling, gives rise to such large Alfvén speeds in the corona that it becomes difficult to satisfy the conditions for the generation of type II radio bursts. As a result, CMEs propagating in the corona/wind of flare stars are expected to be “radio-quiet” as regards type II bursts. In view of this, we suggest that, in the context of type II bursts, scaling from solar to stellar flares is of limited effectiveness.
Identifying the 3FHL Catalog. III. Results of the CTIO-COSMOS Optical Spectroscopy Campaign
Authors: Desai A. , Marchesi S. , Rajagopal M. , Ajello M. 
Published: February 2019

Abstract
Active galactic nuclei (AGNs) with their relativistic jets pointed toward the observer form a subclass of luminous γ-ray sources commonly known as blazars. The study of blazars is essential to improve our understanding of the AGNs emission mechanisms and evolution, as well as to map the extragalactic background light. To do so, however, one needs to classify and measure a redshift for a large sample of these sources correctly. The Third Fermi-LAT Catalog of High-Energy Sources (3FHL) contains ≈1160 blazars reported at energies greater than 10 GeV. However, ∼25% of these sources are unclassified and ∼50% lack redshift information. To increase the spectral completeness of the 3FHL catalog, we are working on an optical spectroscopic follow-up campaign using 4 m and 8 m telescopes. In this paper, we present the results of the second part of this campaign, where we observed 23 blazars using the 4 m telescope at Cerro Tololo Interamerican Observatory in Chile. We report that all the 23 sources are classified as BL Lacs, a confirmed redshift measurement for three sources, a redshift lower limit for two sources, and a tentative redshift measurement for three sources.
Strongly Bipolar Inner Ejecta of the Normal Type IIP Supernova ASASSN-16at
Authors: Bose Subhash , Dong Subo , Elias-Rosa N. , Shappee B. J. , Bersier David , Benetti Stefano , Stritzinger M. D. , Grupe D. , Kochanek C. S. , Prieto J. L. , Chen Ping , Kuncarayakti H. , Mattila Seppo , Morales-Garoffolo Antonia , Morrell Nidia , Onori F. , Reynolds Thomas M , Siviero A. , Somero Auni , Stanek K. Z. , Terreran Giacomo , Thompson Todd A. , Tomasella L. , Ashall C. , Gall Christa , Gromadzki M. , Holoien T. W.-S. 
Published: February 2019

Abstract
We report distinctly double-peaked Hα and Hβ emission lines in the late-time, nebular-phase spectra (≳200 days) of the otherwise normal at early phases (≲100 days) type IIP supernova ASASSN-16at (SN 2016X). Such distinctly double-peaked nebular Balmer lines have never been observed for a type II SN. The nebular-phase Balmer emission is driven by the radioactive 56Co decay, so the observed line profile bifurcation suggests a strong bipolarity in the 56Ni distribution or in the line-forming region of the inner ejecta. The strongly bifurcated blueshifted and redshifted peaks are separated by ∼3 × 103 km s−1 and are roughly symmetrically positioned with respect to the host-galaxy rest frame, implying that the inner ejecta are composed of two almost-detached blobs. The red peak progressively weakens relative to the blue peak, and disappears in the 740 days spectrum. One possible reason for the line-ratio evolution is increasing differential extinction from continuous formation of dust within the envelope, which is also supported by the near-infrared flux excess that develops after ∼100 days.
Sample size for inspection intended to manage risk within mixed consignments
Authors: Lane Stephen E. , Cannon Rob M. , Arthur Anthony D. , Robinson Andrew P. 
Published: February 2019

The identification of a lot, and the size of the random sample taken for plant products, is justified by appeal to International Standards for Phytosanitary Measures No. 31, “Methodologies for Sampling of Consignments”. ISPM 31 notes that “A lot to be sampled should be a number of units of a single commodity identifiable by its homogeneity [...]” and “Treating multiple commodities as a single lot for convenience may mean that statistical inferences cannot be drawn from the results of the sampling.”
However, consignments are frequently heterogeneous, either because the same commodities have multiple sources or because there are several different commodities. The ISPM 31 prescription creates a substantial burden on border inspection because it suggests that heterogeneous populations must be split into homogeneous sub-populations from which separate samples of nominal size must be taken.
We demonstrate that if consignments with known heterogeneity are treated as stratified populations and the random sample of units is allocated proportionally based on the number of units in each stratum, then the nominal sensitivity at the consignment level is achieved if our concern is the level of contamination in the entire consignment taken as a whole. We argue that unknown heterogeneity is no impediment to appropriate statistical inference. We conclude that the international standard is unnecessarily restrictive.
Les adolescents face aux violences numériques
Authors: Jehel Sophie 
Published: February 2019

La circulation des images violentes est favorisée par les stratégies des plateformes numériques visant l’ « addiction » à leurs dispositifs et la circulation des affects : elle stimule les interactions, permettant la collecte de données personnelles par leurs algorithmes. Faire face aux violences numériques requiert pour les adolescents un double travail auquel se consacre cet article : conjointement au « travail du clic » que représentent les activités de partage, de recommandations, de commentaires qu’elles suscitent, s’ajoute un travail en profondeur sur les émotions ressenties face aux images violentes, sexuelles et haineuses, et leur expression sur les plateformes. Le travail émotionnel des adolescents consiste à gérer les écarts entre les différentes règles de sentiment auxquels ils se réfèrent, celles de la plateforme, celles des pairs, celles des parents. Ils ne sont pas dotés également des capacités pour accomplir ce travail et construire des postures autonomes, résistant aux logiques de violence qui affectent leurs circulations numériques. Certains développent des attitudes d’adhésion aux logiques de violence et perdent la capacité à écouter leurs propres sentiments, à protéger leur subjectivité. L’instrumentalisation commerciale des émotions comprend un risque de réification auquel les adolescents sont particulièrement exposés et qui renforce le cycle des violences numériques. L’article s’appuie notamment sur une enquête qualitative menée auprès de 200 adolescents de milieux sociaux et scolaires différenciés entre 2015 et 2017 par entretiens semi-directifs.
Efficacy of voice therapy in patients with puberphonia- a 15-year experience
Authors: De Alwis A. S. R. , Rupasinghe R. J. S. , Kumarasinghe I. , Weerasinghe A. , Perera R. , Jayasuriya C. 
Published: February 2019

BackgroundPuberphonia is the perseverance of high pitched voice after the pubertal age in males which causes a huge psychosocial impact. Voice therapy is one modality of management of Puberphonia. AimThe Objective of our study was to evaluate the efficacy of voice therapy in patients as the sole treatment to improve the pitch and quality of voice, the psychosocial impact and patient's satisfaction. MethodsA retrospective study was carried out on 71 patients who were presented to ENT unit at the National hospital of Sri Lanka for fifteen years from 2002. Pre and post voice therapy subjective assessment was done by the speech therapist for pitch and quality and patient’s perceptual assessment using an analog scale (0-extremely poor to 10-normal voice) and a psychosocial impact assessment was also done. ResultsThe time duration of voice therapy ranged from 1 to 10 months (average-3.6 months). Pitch and quality of the voice became normal in 78.9% and 35.2% of patients respectively. Pre-therapy perceptual score range(PSR) was 0 to 6 (mean-3.0). Post-therapy PSR was 5 to 10 (mean-7.7). 95.8% patients had improved psychosocial impact and patient satisfaction after voice therapy. Remaining opted for surgical management. ConclusionVoice therapy significantly improves the pitch, patient's satisfaction and psychosocial impact and can be used as an effective modality of treatment for Puberphonia.