bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Isolated White Dwarf with 317 s Rotation and Magnetic Emission
Authors: Reding Joshua S. , Hermes J. J. , Vanderbosch Z. , Dennihy E. , Kaiser B. C. , Mace C. B. , Dunlap B. H. , Clemens J. C. 
Published: April 2020

Abstract
We report the discovery of short-period photometric variability and modulated Zeeman-split hydrogen emission in SDSSJ125230.93−023417.72 (EPIC 228939929), a variable white dwarf star observed at long cadence in K2 Campaign 10. The behavior is associated with a magnetic (B = 5.0 MG) spot on the stellar surface, making the 317.278 s period a direct measurement of the stellar rotation rate. This object is therefore the fastest-rotating, apparently isolated (without a stellar companion) white dwarf yet discovered and the second found to exhibit chromospheric Balmer emission after GD 356, in which the emission has been attributed to a unipolar inductor mechanism driven by a possible rocky planet. We explore the properties and behavior of this object, and consider whether its evolution may hold implications for white dwarf mergers and their remnants.
The Effects of Tilt on the Images of Black Hole Accretion Flows
Authors: White Christopher J. , Dexter Jason , Blaes Omer , Quataert Eliot 
Published: April 2020

Abstract
We analyze two 3D general-relativistic magnetohydrodynamic accretion simulations in the context of how they would manifest in Event Horizon Telescope (EHT) observations of supermassive black holes. The two simulations differ only in whether the initial angular momentum of the plasma is aligned with the rapid (a = 0.9) spin of the black hole. Both have low net magnetic flux. Ray tracing is employed to generate resolved images of the synchrotron emission. When using parameters appropriate for Sgr A* and assuming a viewing angle aligned with the black hole spin, we find the most prominent difference is that the central shadow in the image is noticeably eccentric in tilted models, with the ring of emission relatively unchanged. Applying this procedure to M87 with a viewing angle based on the large-scale jet, we find that adding tilt increases the angular size of the ring for fixed black hole mass and distance, while at the same time increasing the number of bright spots in the image. Our findings illustrate observable features that can distinguish tilted from aligned flows. They also show that tilted models can be viable for M87, and that not accounting for tilt can bias inferences of physical parameters. Future modeling of horizon-scale observations should account for potential angular momentum misalignment, which is likely generic at the low accretion rates appropriate for EHT targets.
Asymmetric Structure of the Solar Wind and Heliosphere from IBEX Observations
Authors: Zirnstein E. J. , Dayeh M. A. , McComas D. J. , Sokół J. M. 
Published: April 2020

Abstract
Our heliosphere is formed by the interaction between the dynamic solar wind (SW) and partially ionized, local interstellar medium. “Pickup ions” (PUIs) are produced by charge exchange between SW ions and interstellar neutral atoms and propagate with the SW into the outer heliosphere. Neutralization of these PUIs in the heliosheath creates energetic neutral atoms (ENAs) that are observed near Earth by the Interstellar Boundary Explorer (IBEX). In this study, we analyze the evolution of ENAs observed by IBEX between ∼0.5 and 6 keV from 2009 to 2018, presenting the evolution of ENA spectral indices as a function of latitude in different regions of the sky. Our results show that IBEX ENA spectra reflect unique differences in the northern and southern polar coronal holes (PCHs) as a function of latitude and time. ENA spectra reflect a delayed closure of the southern PCH compared to the north by ∼1–2 yr in solar cycle 24, but then a rapid opening of the southern PCH beginning ∼1–2 yr later, in agreement with evolving SW speeds emanating from the PCHs. While ENA spectra from the front and flanks of the heliosphere exhibit similar behavior, ENA spectra from the back behave differently, suggesting that the heliotail and ENA source structures are significantly different. The mean ENA spectral index observed by IBEX evolves gradually and quasi-periodically over the ∼11 yr solar cycle, reflecting large-scale changes in the PCHs and SW speed. The standard deviation of the spectral index exhibits bumps at times when the SW dynamic pressure changes abruptly.
The Luminosity Distribution of Short Gamma-Ray Bursts under a Structured Jet Scenario
Authors: Guo Qi , Wei Daming , Wang Yuanzhu 
Published: April 2020

Abstract
The joint detection of gravitational wave (GW) and electromagnetic radiation from the binary neutron star merger event GW170817 marks a breakthrough in the field of multi-messenger astronomy. The short gamma-ray burst (sGRB) GRB 170817A, associated with this binary neutron star merger event, has an isotropic-equivalent gamma-ray radiation luminosity of 1.6 × 1047 erg s−1, which is much lower than that of other sGRBs. The measurement of the superluminal movement of the radio afterglow emission confirms the presence of the relativistic jet, and the emission features can be well explained by the structured jet model. In this paper, we calculate the luminosity distribution of sGRBs and its evolution with redshift based on the structured (Gaussian) jet model, and find that the typical luminosity increase with redshift, for nearby sGRBs (such as for luminosity distance less than 200 Mpc) the typical gamma-ray luminosity is just around 1047–1048 erg s−1, which naturally explains the very low radiation luminosity of GRB 170817A. We derived the detection probability of sGRBs by Fermi-GBM and found that the expected detection rate of sGRBs is only about 1 yr−1 within the distance of several hundred Mpc. We explored the effect of the power-law index α of the merger time distribution on the observed characteristics and found that it had little effect on the observed luminosity and viewing-angle distributions. However, it is very interesting that, for different values of α, the distributions of the number of observed sGRBs are quite different, so it is possible to determine the value of α through observed distributions of the number of sGRBs. We used the Bayesian method to make a quantitative analysis and found that the value of α may be identified when the number of observed sGRBs with known redshifts is more than 200. Finally, we compare our results of gamma-ray luminosity distribution with sGRBs with known redshifts, and found that our results are consistent with the observation, which implies that our simulation results can reproduce the observed luminosity distribution well.
Constraining the Milky Way Mass Profile with Phase-space Distribution of Satellite Galaxies
Authors: Li Zhao-Zhou , Qian Yong-Zhong , Han Jiaxin , Li Ting S. , Wang Wenting , Jing Y. P. 
Published: April 2020

Abstract
We estimate the Milky Way (MW) halo properties using satellite kinematic data including the latest measurements from Gaia DR2. With a simulation-based 6D phase-space distribution function (DF) of satellite kinematics, we can infer halo properties efficiently and without bias, and handle the selection function and measurement errors rigorously in the Bayesian framework. Applying our DF from the EAGLE simulation to 28 satellites, we obtain an MW halo mass of

and a concentration of

with the prior based on the M–c relation. The inferred mass profile is consistent with previous measurements but with better precision and reliability due to the improved methodology and data. Potential improvement is illustrated by combining satellite data and stellar rotation curves. Using our EAGLE DF and best-fit MW potential, we provide much more precise estimates of the kinematics for those satellites with uncertain measurements. Compared to the EAGLE DF, which matches the observed satellite kinematics very well, the DF from the semi-analytical model based on the dark-matter-only simulation Millennium II (SAM-MII) over-represents satellites with small radii and velocities. We attribute this difference to less disruption of satellites with small pericenter distances in the SAM-MII simulation. By varying the disruption rate of such satellites in this simulation, we estimate a ∼5% scatter in the inferred MW halo mass among hydrodynamics-based simulations.
MARVEL Analysis of the Measured High-resolution Rovibronic Spectra of the Calcium Monohydroxide Radical (CaOH)
Authors: Wang Yixin , Owens Alec , Tennyson Jonathan , Yurchenko Sergei N. 
Published: April 2020

Abstract
The calcium monohydroxide radical (CaOH) is an important astrophysical molecule relevant to cool stars and rocky exoplanets, among other astronomical environments. Here, we present a consistent set of highly accurate rovibronic (rotation-vibration-electronic) energy levels for the five lowest electronic states (

,

,

,

, and

) of CaOH. A comprehensive analysis of the published spectroscopic literature on this system has allowed 1955 energy levels to be determined from 3204 rovibronic experimental transitions, all with unique quantum number labeling and measurement uncertainties. The data set covers rotational excitation up to J = 62.5 for molecular states below 29,000 cm−1. The analysis was performed using the Measured Active Rotational-Vibrational Energy Levels algorithm, which is a robust procedure based on the theory of spectroscopic networks. The data set provided will significantly aid future interstellar, circumstellar, and atmospheric detections of CaOH, as well as assist in the design of efficient laser cooling schemes in ultracold molecule research and precision tests of fundamental physics.
A database of functional traits for spiders from native forests of the Iberian Peninsula and Macaronesia
Authors: Macías-Hernández Nuria , Ramos Cândida , Domènech Marc , Febles Sara , Santos Irene , Arnedo Miquel , Borges Paulo , Emerson Brent , Cardoso Pedro 
Published: April 2020

There is an increasing demand for databases including species trait information for biodiversity and community ecology studies. The existence of trait databases is useful for comparative studies within taxa or geographical regions, but there is low availability of databases for certain organisms. Here we present an open access functional trait database for spiders from Macaronesia and the Iberian Peninsula, recording several morphological and ecological traits related to the species life histories, microhabitat and trophic preferences.We present a database that includes 12 biological traits for 506 spider species present in natural forests of the Iberian Peninsula (Spain) and three Macaronesian archipelagoes (Azores, Madeira and Canary Islands). The functional trait database consists of two sections:individual-level data for six morphological traits (total body size, prosoma length, prosoma width, prosoma height, tibia I length and fang length), based on direct measurements of 2844 specimens of all spider species; andspecies-level aggregate data for 12 traits (same 6 morphological traits as in the previous section plus dispersal ability, vertical stratification, circadian activity, foraging strategy, trophic specialization and colonization status), based on either the average of the direct measurements or bibliographic searches.individual-level data for six morphological traits (total body size, prosoma length, prosoma width, prosoma height, tibia I length and fang length), based on direct measurements of 2844 specimens of all spider species; andspecies-level aggregate data for 12 traits (same 6 morphological traits as in the previous section plus dispersal ability, vertical stratification, circadian activity, foraging strategy, trophic specialization and colonization status), based on either the average of the direct measurements or bibliographic searches.This functional trait database will serve as a data standard for currently ongoing analyses that require trait and functional diversity statistics.
Le progrès technique, clef de la transition énergétique ?
Authors: Papon Pierre 
Published: April 2020

Si la réalité du changement climatique fait aujourd’hui l’objet d’un très large consensus scientifique, la façon dont nous pouvons y faire face, en revanche, n’est pas envisagée de la même manière par tout le monde. Comme dans toute crise de grande ampleur, les regards divergent suivant que l’on est du côté des pessimistes — qui envisagent le pire et vont parfois jusqu’à adopter des positions « survivalistes » — ou des optimistes — qui considèrent que l’on finira par s’adapter et trouver des solutions, notamment grâce au progrès technique. Ces optimistes convaincus du « solutionnisme technologique » ont-ils raison ? Le progrès technique sera-t-il au rendez-vous pour accompagner la transition énergétique ? Dans ce deuxième volet de la série que Futuribles consacre aux questions climatiques et énergétiques, Pierre Papon examine les différentes voies ouvertes par le progrès technologique pour faire évoluer nos modes de production énergétique. Après avoir rappelé la lenteur (constatée historiquement) des transitions énergétiques, il souligne que la « décarbonation » de l’énergie est intimement liée à celle de la production électrique dont un élément clef concerne le stockage pour faire face à l’intermittence des énergies renouvelables. Il précise les différentes évolutions ou ruptures techniques envisageables en ce domaine, ainsi qu’en matière d’énergie nucléaire (qui fait partie des énergies non carbonées), l’horizon auquel elles pourraient se concrétiser (rarement antérieur à 2050) et les obstacles qu’elles pourraient rencontrer. Une incertitude majeure subsiste : comment réaliser la neutralité carbone de l’industrie ? En somme, un peu d’espoir, une longue attente… S.D.
Quel avenir pour Taiwan ?
Authors: Cavalli Inès 
Published: April 2020

La revue Futuribles n’a pas vocation à rendre compte des consultations électorales, mais celles-ci peuvent parfois nous inciter à réfléchir aux futurs possibles. Peut-être est-ce le cas des élections intervenues en janvier à Taiwan, île de 23,5 millions d’habitants divisée entre les tenants d’un rapprochement avec la Chine, et ceux qui sont convaincus de son identité propre, veulent la défendre, voire à terme assurer son indépendance. Taiwan est un acteur stratégique important dans la compétition sino-américaine dans la région Asie-Pacifique mais, au-delà de cet aspect, c’est avec Hong Kong un des bastions de la démocratie à l’occidentale dans le monde chinois. Il est donc intéressant d’en mieux comprendre la spécificité et les grandes tendances d’évolution. Tel est l’objet de la tribune que nous livre ici Inès Cavalli suite aux élections intervenues le 11 janvier 2020. H.J.
Accueillir un enfant de l’Assistance publique dans un département dépeuplé. Nourrices et nourriciers des Basses-Alpes sous la III e République
Authors: Grenut Isabelle 
Published: April 2020

Entre 1874 et 1923, 805 filles et garçons, en majorité des enfants naturels, sont admis à l’assistance dans les Basses-Alpes, soit des effectifs relativement faibles. Or, dans ce département très touché par le dépeuplement, l’inspection de l’Assistance publique peine à engager des nourrices « au sein », et doit diversifier son recrutement. De plus, l’élévation du niveau de vie, en parti- culier après la Première Guerre mondiale, contribue à détourner les jeunes agricultrices de cette activité contraignante et peu lucrative. Cependant, la loi du 19 juin 1923 permettant l’adoption des enfants mineurs ouvre d’autres perspectives aux enfants abandonnés, et concourt à faire évoluer le statut des familles nourricières.
DETERMINATION OF RADON AND NATURAL RADIOACTIVITY CONCENTRATION IN SOME BUILDING MATERIALS USED IN IZMIR, TURKEY
Authors: Hatungimana Daniel , Taşköprü Caner , İçhedef Mutlu , Saç Müslim Murat , Yazıcı Şemsi , Mardani-Aghabaglou Ali 
Published: April 2020

ABSTRACTThe aim of this study is to determine the radon and natural radioactivity concentrations of some building materials and to assess the radiation hazard associated with those mortar materials when they are used in the construction of dwellings. Radon measurements were realized by using LR-115 Type 2 solid state nuclear track detectors. Radon activity concentrations of these materials were found to vary between 130.00 ± 11.40 and 1604.06 ± 40.5 Bq m−3. The natural radioactivity in selected mortar materials was analyzed by using scintillation gamma spectroscopy. The activity concentrations for 226Ra, 232Th and 40K for the studied mortar materials ranged from ND to 48.5 ± 7.0 Bq kg−1, ND to 41.0 ± 6.4 Bq kg−1 and ND to 720.4 ± 26.8 Bq kg−1, respectively. Radium equivalent activities, external and internal hazard indexes, gamma and alpha indexes and absorbed gamma dose rates were calculated to assess the radiation hazard of the natural radioactivity in studied samples. The calculated Raeq values of all samples were found to be lower than the limit of 370 Bq kg−1 set for building materials. The estimated hazard index values were found to be under the unity and the absorbed dose rate values were also below the worldwide average of 84 nGy h−1.
EFFECT OF DIFFERENT TYPES OF FIBER UTILIZATION ON MECHANICAL PROPERTIES OF RECYCLED AGGREGATE CONCRETE CONTAINING SILICA FUME
Authors: Altun Muhammet Gökhan , Oltulu Meral 
Published: April 2020

ABSTRACT
The use of recycled aggregate (RA) instead of natural aggregate (NA) in concrete is necessary for environmental protection and the effective utilization of resources. The addition of recycled aggregates in concrete increases shrinkage, porosity and decreases the mechanical properties compared to that of normal concrete. This study was aimed at investigating how the addition of various proportions of polypropylene and steel fiber affect the mechanical properties of recycled aggregate concrete (RAC). The natural coarse aggregates (NCAs) used in the production of normal concrete (NC) were replaced in 30% and 50% proportions by recycled coarse aggregates (RCAs) obtained from the demolished buildings. In this case, a polypropylene fiber (PF) content of 0.1% and steel fiber (SF) 1% and 2% volume fractions were used, along with hybrid fibers-a combination of the two. While the material performance of RAC compared to NC is analyzed by reviewing existing published literature, it is not evident what the use of RCAs and hybrid fibers have on the mechanical properties of concrete. The results showed that the compressive strength, flexural strength and impcat resistance of RAC were reduced as the percentage of RCAs increased. It was observed that the compressive strength was increased with the addition of 1% steel fiber in the RAC. The flexural and impact performance of steel fiber-reinforced concrete (Specimens NC and RAC) was increased as the volume fractions of steel fiber increased. The hybrid fiber reinforced concretes showed the best results in their mechanical performance of all the concrete groups.
THE SIMULATION ANALYSIS OF A PROPOSED ‘HYDRONIC RADIATOR’ SYSTEM TOWARDS LOW COST HOUSING OPERATION IN TEMPERATE AND HOT TROPICAL CLIMATES
Authors: Noguchi Masa , Ooi Koon Beng 
Published: April 2020

ABSTRACT
Fuel poverty is one of the global concerns affecting not only users' financial capacity or affordability for maintaining housing operation but also the occupants' health and wellbeing. Space heating and cooling require a relatively large amount of domestic energy use in housing. Therefore, this study was formed with the aim to propose an innovative approach to utilising free, clean renewable sources of energy applicable to the space heating and cooling of housing in both cold and hot regions. Accordingly, housing test facilities based in Melbourne, Australia, and Kuching, Malaysia, were selected and used for this study that examined the thermal performance of a proposed ‘hydronic radiator’ (HR) system through simulation and onsite measurements. The geothermal heat capacity of a ‘vertical ground heat exchanger’ (VGHE) installed in the house in Melbourne was examined previously by the authors and the VGHE measured data was also applied to this HR performance simulation. The water that circulates through the HRs is heated by sunlight and VGHE or cooled by night sky radiation. This study drew conclusions that the sole utilisation of renewable sources through these proposed HR space heating and cooling systems can provide thermally accessible or comfortable indoor living environments in both heating or cooling dominant regions. Thus, fuel poverty issues may be alleviated through HR system application. The HRs can remove a ‘sensible’ portion of metabolic heat, but they cannot effectively contribute to the ‘latent’ heat removal. Thus, the future potential use or effect of ‘flow-through’ HRs, which are integrated into a underfloor air distribution (UFAD) plenum, was also dsicussed in this study. In the test house located in Melbourne, the flow-through HR UFAD system is currently under development. Therefore, the performance will be measured once the system has come into operation for further testing.
Une évolution singulière, de la terre vers l’eau : la dendrochronologie
Authors: Guibal Frédéric 
Published: April 2020

Née dans les régions semi-arides du S.O. des États-Unis des travaux d’un astronome, A. E. Douglass, qui cherchait une relation entre les cycles solaires et le climat terrestre, la dendrochronologie s’est rapidement affirmée comme une robuste méthode de datation du bois. Après un transfert de son application des zones semi-arides aux zones tempérées, elle s’est ouvert un champ d’application immense en passant de l’étude des bois secs et carbonisés des milieux terrestres aux bois gorgés d’eau des zones humides, des milieux subaquatiques et maritimes.
À propos de la voile latine : la mosaïque de Kelenderis et les Stereometrica (II, 48-49) d’Héron d’Alexandrie
Authors: Pomey Patrice 
Published: April 2020

La mosaïque de Kelenderis (Turquie), datée du v
e s. ap. J.-C., constitue à ce jour le témoignage le plus précis d’un navire équipé d’une voile de la famille des voiles latines et plus précisément du type dit « voile latine orientale » (settee sail) à voile trapézoïdale. Ce document remonte de ce fait de deux siècles la certitude de l’usage de la voile latine en Méditerranée. Cependant, elle n’a fait l’objet jusqu’à présent que d’interprétations rapides (P. Pomey), voire erronées (Z. Friedmann). Aussi propose-t-on ici une nouvelle étude plus complète et plus détaillée de ce document exceptionnel d’une très grande richesse.Son analyse conduit à admettre que la voile du bateau de Kelenderis est particulièrement élaborée et serait par conséquent le fruit d’un long processus d’évolution. Selon l’hypothèse la plus vraisemblable avancée par certains auteurs (L. Basch), cette origine serait à rechercher du côté d’Alexandrie, foyer réputé d’innovations notamment dans le domaine maritime. Le graffito d’Anfouchi pourrait même faire remonter l’apparition de la pure voile latine triangulaire au i
er s. de notre ère, ce qui implique une double évolution conduisant à la voile latine triangulaire et à la voile latine trapézoïdale. Plusieurs indices suggèrent que la communauté Copte aurait joué un rôle important dans cette évolution.L’existence d’une formule de calcul de la surface d’une voile triangulaire du type voile latine chez Héron d’Alexandrie (Stereometrica, II, 48-49), viendrait ainsi confirmer le rôle d’Alexandrie dans le développement de cette voile. Même si sa date et son origine restent incertaines, ce texte s’inscrit dans la tradition alexandrine et montre l’importance pris par ce nouveau type de gréement.Le rapprochement de ces deux documents permet d’envisager sous un angle nouveau le problème de l’apparition et de l’évolution de la voile latine.