bluuebunny/crossref_metadata_2025_split huggingface dataset:
Detection of a Low-frequency Cosmic Radio Transient Using Two LWA Stations
Authors: Varghese S. S. , Obenberger K. S. , Dowell J. , Taylor G. B. 
Published: April 2019

Abstract
We report the detection of a potential cosmic radio transient source using the two stations of the Long Wavelength Array. The transient was detected on 2017 October 18 08:47 UTC near the celestial equator while reducing 10,240 hr of archival all-sky images from the LWA1 and LWA-SV stations. The detected transient at 34 MHz has a duration of 15–20 s and a flux density of 842 ± 116 Jy at LWA1 and 830 ± 92 Jy at LWA-SV. The transient source has not repeated, and its nature is not well understood. The Pan-STARRS optical telescope has detected a supernova that occurred on the edge of the position error circle of the transient on the same day.
The R-Process Alliance: Discovery of a Low-α, r-process-enhanced Metal-poor Star in the Galactic Halo
Authors: Sakari Charli M. , Roederer Ian U. , Placco Vinicius M. , Beers Timothy C. , Ezzeddine Rana , Frebel Anna , Hansen Terese , Sneden Christopher , Cowan John J. , Wallerstein George , Farrell Elizabeth M. , Venn Kim A. , Matijevič Gal , Wyse Rosemary F. G. , Bland-Hawthorn Joss , Chiappini Cristina , Freeman Kenneth C. , Gibson Brad K. , Grebel Eva K. , Helmi Amina , Kordopatis Georges , Kunder Andrea , Navarro Julio , Reid Warren , Seabroke George , Steinmetz Matthias , Watson Fred 
Published: April 2019

Abstract
A new moderately r-process-enhanced metal-poor star, RAVE J093730.5−062655, has been identified in the Milky Way halo as part of an ongoing survey by the R-Process Alliance. The temperature and surface gravity indicate that J0937−0626 is likely a horizontal branch star. At [Fe/H] = −1.86, J0937−0626 is found to have subsolar [X/Fe] ratios for nearly every light, α, and Fe-peak element. The low [α/Fe] ratios can be explained by an ∼0.6 dex excess of Fe; J0937−0626 is therefore similar to the subclass of “iron-enhanced” metal-poor stars. A comparison with Milky Way field stars at [Fe/H] = −2.5 suggests that J0937−0626 was enriched in material from an event, possibly a Type Ia supernova, that created a significant amount of Cr, Mn, Fe, and Ni and smaller amounts of Ca, Sc, Ti, and Zn. The r-process enhancement of J0937−0626 is likely due to a separate event, which suggests that its birth environment was highly enriched in r-process elements. The kinematics of J0937−0626, based on Gaia DR2 data, indicate a retrograde orbit in the Milky Way halo; J0937−0626 was therefore likely accreted from a dwarf galaxy that had significant r-process enrichment.
The Green Bank Ammonia Survey: A Virial Analysis of Gould Belt Clouds in Data Release 1
Authors: Kerr Ronan , Kirk Helen , Di Francesco James , Keown Jared , Chen Mike , Rosolowsky Erik , Offner Stella S. R. , Friesen Rachel , Pineda Jaime E. , Shirley Yancy , Redaelli Elena , Caselli Paola , Punanova Anna , Seo Youngmin , Alves Felipe , Chacón-Tanarro Ana , How-Huan Chen Hope 
Published: April 2019

Abstract
We perform a virial analysis of starless dense cores in three nearby star-forming regions: L1688 in Ophiuchus, NGC 1333 in Perseus, and B18 in Taurus. Our analysis takes advantage of comprehensive kinematic information for the dense gas in all of these regions made publicly available through the Green Bank Ammonia Survey Data Release 1, which is used to estimate internal support against collapse. We combine this information with ancillary data used to estimate other important properties of the cores, including continuum data from the James Clerk Maxwell Telescope Gould Belt Survey for core identification, core masses, and core sizes. Additionally, we used Planck- and Herschel-based column density maps for external cloud weight pressure and Five College Radio Astronomy Observatory 13CO observations for external turbulent pressure. Our self-consistent analysis suggests that many dense cores in all three star-forming regions are not bound by gravity alone, but rather require additional pressure confinement to remain bound. Unlike a recent, similar study in Orion A, we find that turbulent pressure represents a significant portion of the external pressure budget. Our broad conclusion emphasizing the importance of pressure confinement in dense core evolution, however, agrees with earlier work.
Automatic Detection of Interplanetary Coronal Mass Ejections from In Situ Data: A Deep Learning Approach
Authors: Nguyen Gautier , Aunai Nicolas , Fontaine Dominique , Pennec Erwan Le , Bossche Joris Van den , Jeandet Alexis , Bakkali Brice , Vignoli Louis , Blancard Bruno Regaldo-Saint 
Published: April 2019

Abstract
Decades of studies have suggested several criteria to detect interplanetary coronal mass ejections (ICME) in time series from in situ spacecraft measurements. Among them, the most common are an enhanced and smoothly rotating magnetic field, a low proton temperature, and a low plasma beta. However, these features are not all observed for each ICME due to their strong variability. Visual detection is time-consuming and biased by the observer interpretation, leading to non-exhaustive, subjective, and thus hardly reproducible catalogs. Using convolutional neural networks on sliding windows and peak detection, we provide a fast, automatic, and multi-scale detection of ICMEs. The method has been tested on the in situ data from WIND between 1997 and 2015, and on the 657 ICMEs that were recorded during this period. The method offers an unambiguous visual proxy of ICMEs that gives an interpretation of the data similar to what an expert observer would give. We found at a maximum 197 of the 232 ICMEs of the 2010–2015 period (recall 84% ± 4.5%), including 90% of the ICMEs present in the lists of Nieves-Chinchilla et al. and Chi et al. The minimal number of False Positives was 25 out of 158 predicted ICMEs (precision 84% ± 2.6%). Although less accurate, the method also works with one or several missing input parameters. The method has the advantage of improving its performance by just increasing the amount of input data. The generality of the method paves the way for automatic detection of many different event signatures in spacecraft in situ measurements.
Level-resolved Photoionization Cross Sections for Fe i
Authors: Smyth R. T. , Ballance C. P. , Ramsbottom C. A. 
Published: April 2019

Abstract
Significant contributions to the UV opacity in the solar atmosphere have been found to stem from bound-free transitions in neutral iron. As such, accurate cross sections for the photoionisation process are required for a detailed and meaningful analysis. However, existing photoionisation cross sections display large discrepancies across the low-energy region, highlighting the need for further calculations. In this work, we present level-resolved photoionisation cross sections for neutral iron across a wide energy range from a 262 level Dirac R-matrix calculation. Comparisons with existing experimental measurements reveal good agreement in the positions of the various low-energy resonance features. However, additional comparisons with theoretical data sets highlight wide variations. Significant resonance structures at high photon energies are explored by employing an additional series of 262 level and 896 level Dirac R-matrix calculations with a smaller six configuration target. The resulting photoionisation cross sections reproduce the main features from existing experimental observations. The results presented throughout will be useful to those requiring an extensive set of level-resolved photoionisation cross sections for astrophysical applications.
Do Galaxy Morphologies Really Affect the Efficiency of Star Formation During the Phase of Galaxy Transition?
Authors: Koyama Shuhei , Koyama Yusei , Yamashita Takuji , Hayashi Masao , Matsuhara Hideo , Nakagawa Takao , Namiki Shigeru V. , Suzuki Tomoko L. , Fukagawa Nao , Kodama Tadayuki , Lin Lihwai , Morokuma-Matsui Kana , Shimakawa Rhythm , Tanaka Ichi 
Published: April 2019

Abstract
Recent simulations predict that the presence of the stellar bulge suppress the efficiency of star formation (SF) in early-type galaxies, and this “morphological quenching” scenario is supported by many observations. In this study, we discuss the net effect of galaxy morphologies on the star formation efficiency (SFE) during the phase of galaxy transition, on the basis of our CO(J = 1 − 0) observations of 28 local “green valley” galaxies with the Nobeyama 45 m Radio Telescope. We observed 13 disk-dominated and 15 bulge-dominated green valley galaxies at fixed stellar mass (M
*) and star formation rate (SFR), supplemented by 1 disk- and 6 bulge-dominated galaxies satisfying the same criteria from the xCOLD GASS survey. By using a total of 35 green valley galaxies, we reveal that the distributions of molecular gas mass, molecular gas fraction, and SFE of green valley galaxies do not change with their morphologies, suggesting little impact of galaxy morphologies on their SFE, and interestingly, this result is also valid for normal star-forming galaxies on the SF main sequence selected from the xCOLD GASS galaxies. On the other hand, we find that ∼20% of the bulge-dominated green valley galaxies do not show significant CO emission line, showing high SFEs for their M
* and SFR. These molecular gas deficient sources that are identified only in the bulge-dominated green valley galaxies may represent an important population during the quenching phase under the influence of the stellar bulge, but our results suggest that the presence of the stellar bulge does not decrease the efficiency of ongoing SF, in contrast to the prediction of the morphological quenching scenario.
Accueillir un enfant étrange-r
Authors: Le Calvez Annie , Bass Denise 
Published: April 2019

Entretien retranscrit sous forme de questions-réponses à partir d’une idée générale : comme cela se passe-t-il quand l’assistante familiale accueille un jeune ? Les questions posées abordent le quotidien de l’accueil : autoriser ou non l’accès à Internet, l’usage du portable, les devoirs, la nourriture, les normes familiales, les interdits, les rapports avec les enfants de la famille d’accueil, les deuils familiaux, les enfants à comportements violents…	Finalement, la formation est-elle importante dans cette profession atypique ? Quelle est la part de l’engagement personnel quand on choisit de faire ce métier ?
Le souffle du désir dans les institutions
Authors: Aujard Chloé 
Published: April 2019

L’auteur fait partager sa réflexion sur la difficulté à maintenir la créativité et le désir d’être avec un bébé quand on est professionnelle dans une pouponnière. Face à six bébés ayant déjà vécu des moments souvent dramatiques dans leurs relations, face aux multiples recommandations et réglementations de l’institution, l’auxiliaire de puériculture, même expérimentée, peut se retrouver en souffrance et se voir envahie d’émotions « négatives » qui écornent son idéal professionnel et sa capacité d’investissement de ces petits humains, pourtant en grande demande. L’auteur fait part de son expérience du travail en équipe pluridisciplinaire et évoque le cas d’un bébé difficile à investir. Apathique, le regard se détournant de l’adulte, avec une salivation exacerbée, Nathan attire tout sauf la sympathie sur lui. Cependant, une écoute des auxiliaires de puériculture, une mise en mots et en sens de leurs ressentis négatifs, un travail d’équipe autour de lui, tous ces éléments vont le transformer peu à peu jusqu’à le mener aux portes d’une famille d’accueil.
Linkage disequilibrium and within-breed genetic diversity in Iranian Zandi sheep
Authors: Ghoreishifar Seyed Mohammad , Moradi-Shahrbabak Hossein , Parna Nahid , Davoudi Pourya , Khansefid Majid 
Published: April 2019

Abstract. This research aimed to measure the extent of linkage disequilibrium (LD), effective population size (Ne), and runs of homozygosity (ROHs) in one of the major Iranian sheep breeds (Zandi) using 96 samples genotyped with Illumina Ovine SNP50 BeadChip. The amount of LD (r2) for single-nucleotide polymorphism (SNP) pairs in short distances (10–20 kb) was 0.21±0.25 but rapidly decreased to 0.10±0.16 by increasing the distance between SNP pairs (40–60 kb). The Ne of Zandi sheep in past (approximately 3500 generations ago) and recent (five generations ago) populations was estimated to be 6475 and 122, respectively. The ROH-based inbreeding was 0.023. We found 558 ROH regions, of which 37 % were relatively long (> 10 Mb). Compared with the rate of LD reduction in other species (e.g., cattle and pigs), in Zandi, it was reduced more rapidly by increasing the distance between SNP pairs. According to the LD pattern and high genetic diversity of Zandi sheep, we need to use an SNP panel with a higher density than Illumina Ovine SNP50 BeadChip for genomic selection and genome-wide association studies in this breed.
The distribution of sea-salt aerosol in the global troposphere
Authors: Murphy Daniel M. , Froyd Karl D. , Bian Huisheng , Brock Charles A. , Dibb Jack E. , DiGangi Joshua P. , Diskin Glenn , Dollner Maximillian , Kupc Agnieszka , Scheuer Eric M. , Schill Gregory P. , Weinzierl Bernadett , Williamson Christina J. , Yu Pengfei 
Published: April 2019

Abstract. We present the first data on the concentration of sea-salt aerosol throughout
most of the depth of the troposphere and over a wide range of latitudes,
which were obtained during the Atmospheric Tomography (ATom) mission.
Sea-salt concentrations in the upper troposphere are very small, usually less
than 10 ng per standard m3 (about 10 parts per trillion by mass) and
often less than 1 ng m−3. This puts stringent limits on the
contribution of sea-salt aerosol to halogen and nitric acid chemistry in the
upper troposphere. Within broad regions the concentration of sea-salt aerosol
is roughly proportional to water vapor, supporting a dominant role for wet
scavenging in removing sea-salt aerosol from the atmosphere. Concentrations
of sea-salt aerosol in the winter upper troposphere are not as low as in the
summer and the tropics. This is mostly a consequence of less wet scavenging
in the drier, colder winter atmosphere. There is also a source of sea-salt
aerosol over pack ice that is distinct from that over open water. With a
well-studied and widely distributed source, sea-salt aerosol provides an
excellent test of wet scavenging and vertical transport of aerosols in
chemical transport models.
The global climatology of the intensity of the ionospheric sporadic E layer
Authors: Yu Bingkun , Xue Xianghui , Yue Xin'an , Yang Chengyun , Yu Chao , Dou Xiankang , Ning Baiqi , Hu Lianhuan 
Published: April 2019

Abstract. On the basis of S4max data retrieved from COSMIC GPS radio occultation
measurements, the long-term climatology of the intensity of Es layers is
investigated for the period from December 2006 to January 2014. Global maps
of Es intensity show the high-spatial-resolution geographical distribution
and strong seasonal dependence of Es layers. The maximum intensity of
Es occurs over the mid-latitudes, and its value in summer is 2–3 times
larger than that in winter. A relatively strong Es layer is observed at
the North Pole and South Pole, with a distinct boundary dividing the mid-latitudes
and high latitudes along the 60–80∘ geomagnetic
latitude band. The simulation results show that the convergence of vertical
ion velocity could partially explain the seasonal dependence of Es
intensity. Furthermore, some disagreements between the distributions of the
calculated divergence of vertical ion velocity and the observed Es
intensity indicate that other processes, such as the vertical motions of
gravity waves, magnetic-field effects, meteoric mass influx into Earth's
atmosphere, and the chemical processes of metallic ions, should also be
considered as they may also play an important role in the spatial and
seasonal variations in Es layers.
Multi-decadal atmospheric and marine climate variability in southern Iberia during the mid- to late-Holocene
Authors: Schirrmacher Julien , Weinelt Mara , Blanz Thomas , Andersen Nils , Salgueiro Emília , Schneider Ralph R. 
Published: April 2019

Abstract. To assess the regional multi-decadal to multi-centennial climate variability along the
southern Iberian Peninsula during the mid- to late-Holocene record of paleo-environmental
indicators from marine sediments were established for two sites in the Alboran Sea
(ODP-161-976A) and the Gulf of Cádiz (GeoB5901-2). High-resolution records of organic
geochemical properties and planktic foraminiferal assemblages are used to decipher
precipitation and vegetation changes as well as hydrological conditions with respect to
sea surface temperature (SST) and marine primary productivity (MPP). As a proxy for
precipitation change, records of plant-derived n-alkane composition suggest a series of
five distinct dry episodes in southern Iberia at 5.4±0.3 ka cal BP, from 5.1 to
4.9±0.1 ka cal BP, from 4.8 to 4.7±0.1 ka cal BP, from 4.4 to 4.3±0.1 ka cal BP, and at 3.7±0.1 ka cal BP. During each dry episode the
vegetation suffered from reduced water availability. Interestingly, the dry phase from
4.4 to 4.3±0.1 ka cal BP is followed by a rapid shift towards wetter conditions
revealing a more complex pattern in terms of its timing and duration than was described
for the 4.2 ka event in other regions. The series of dry episodes as well as closely
connected hydrological variability in the Alboran Sea were probably driven by NAO-like
(North Atlantic Oscillation) variability. In contrast, surface waters in the Gulf of
Cádiz appear to have responded more directly to North Atlantic cooling associated
with Bond events. In particular, during Bond events 3 and 4, a pronounced increase in
seasonality with summer warming and winter cooling is found.
Freshwater resources under success and failure of the Paris climate agreement
Authors: Heinke Jens , Müller Christoph , Lannerstad Mats , Gerten Dieter , Lucht Wolfgang 
Published: April 2019

Abstract. Population growth will in many regions increase the pressure on water resources and
likely increase the number of people affected by water scarcity. In parallel, global
warming causes hydrological changes which will affect freshwater supply for human use in
many regions. This study estimates the exposure of future population to severe
hydrological changes relevant from a freshwater resource perspective at different levels
of global mean temperature rise above pre-industrial level (ΔTglob).
The analysis is complemented by an assessment of water scarcity that would occur without
additional climate change due to population change alone; this is done to identify the
population groups that are faced with particularly high adaptation challenges. The
results are analysed in the context of success and failure of implementing the Paris
Agreement to evaluate how climate mitigation can reduce the future number of people
exposed to severe hydrological change. The results show that without climate mitigation
efforts, in the year 2100 about 4.9 billion people in the SSP2 population scenario would
more likely than not be exposed to severe hydrological change, and about
2.1 billion of them would be faced with particularly high adaptation challenges due to
already prevailing water scarcity. Limiting warming to 2 ∘C by a successful
implementation of the Paris Agreement would strongly reduce these numbers to 615 million
and 290 million, respectively. At the regional scale, substantial water-related risks
remain at 2 ∘C, with more than 12 % of the population exposed to severe
hydrological change and high adaptation challenges in Latin America and the Middle East
and north Africa region. Constraining ΔTglob to 1.5 ∘C would
limit this share to about 5 % in these regions.
The benefits of spatial resolution increase in global simulations of the hydrological cycle evaluated for the Rhine and Mississippi basins
Authors: Benedict Imme , van Heerwaarden Chiel C. , Weerts Albrecht H. , Hazeleger Wilco 
Published: April 2019

Abstract. To study the global hydrological cycle and its response to a
changing climate, we rely on global climate models (GCMs) and global
hydrological models (GHMs). The spatial resolution of these models is
restricted by computational resources and therefore limits the processes and
level of detail that can be resolved. Increase in computer power therefore
permits increase in resolution, but it is an open question where this
resolution is invested best: in the GCM or GHM. In this study, we evaluated
the benefits of increased resolution, without modifying the representation of
physical processes in the models. By doing so, we can evaluate the benefits
of resolution alone. We assess and compare the benefits of an increased
resolution for a GCM and a GHM for two basins with long observational
records: the Rhine and Mississippi basins. Increasing the resolution of a GCM
(1.125 to 0.25∘) results in an improved precipitation budget over the
Rhine basin, attributed to a more realistic large-scale circulation. These
improvements with increased resolution are not found for the Mississippi
basin, possibly because precipitation is strongly dependent on the
representation of still unresolved convective processes. Increasing the
resolution of the GCM improved the simulations of the monthly-averaged
discharge for the Rhine, but did not improve the representation of extreme
streamflow events. For the Mississippi basin, no substantial differences in
precipitation and discharge were found with the higher-resolution GCM
and GHM. Increasing the
resolution of parameters describing vegetation and orography in the
high-resolution GHM (from 0.5 to 0.05∘) shows no significant
differences in discharge for both basins. A straightforward resolution
increase in the GHM is thus most likely not the best method to improve
discharge predictions, which emphasizes the need for better representation of
processes and improved parameterizations that go hand in hand with resolution
increase in a GHM.
Event-based probabilistic risk assessment of livestock snow disasters in the Qinghai–Tibetan Plateau
Authors: Ye Tao , Liu Weihang , Wu Jidong , Li Yijia , Shi Peijun , Zhang Qiang 
Published: April 2019

Abstract. Understanding risk using quantitative risk assessment
offers critical information for risk-informed reduction actions, investing
in building resilience, and planning for adaptation. This study develops an
event-based probabilistic risk assessment (PRA) model for livestock snow
disasters in the Qinghai–Tibetan Plateau (QTP) region and derives risk
assessment results based on historical climate conditions (1980–2015) and
present-day prevention capacity. In the model, a hazard module was developed
to identify and simulate individual snow disaster events based on boosted
regression trees. By combining a fitted quantitative vulnerability function and
exposure derived from vegetation type and grassland carrying capacity, we
estimated risk metrics based on livestock mortality and mortality rate. In
our results, high-risk regions include the Nyainqêntanglha Range,
Tanggula Range, Bayankhar Mountains and the region between the Kailas Range
and the neighbouring Himalayas. In these regions, annual livestock mortality
rates were estimated as >2 % and mortality was estimated as
>2 sheep unit km−1 at a return period of 20 years.
Prefectures identified with extremely high risk include Guoluo in Qinghai
Province and Naqu, and Shigatse in the Tibet Autonomous Region. In these
prefectures, a snow disaster event with a return period of 20 years or higher
can easily claim total losses of more than 500 000 sheep units. Our
event-based PRA results provide a quantitative reference for preparedness
and insurance solutions in reducing mortality risk. The methodology
developed here can be further adapted to future climate change risk analyses
and provide important information for planning climate change adaption in
the QTP region.