bluuebunny/crossref_metadata_2025_split huggingface dataset:
Superstrong magnetic fields of neutron stars in Be X-ray binaries
Authors: Shi ChangSheng , Zhang ShuangNan , Li XiangDong 
Published: December 2019

AbstractA few Be X-ray binaries might constitute a group of special sources because the neutron stars in them may have superstrong magnetic fields. Generally, the neutron stars have long spin periods and some emission lines are shown from the B type star, which is attributed to an equatorial disc. We re-build new dimensionless torque models and obtain the superstrong magnetic fields of the neutron stars in the Be X-ray binaries in Large Magellanic Cloud, Small Magellanic Cloud and Milky Way when the compressed magnetosphere is considered. Although our conclusions are obtained when the disk accretion mode is considered, the results may be applied the Be X-ray binaries with wind accretion mode. SXP1323 and 4U 2206+54, in which the magnetic fields of the NSs may be close to the maximum ‘virial’ value, are the best objects to explore superstrong magnetic field.
Accretion simulations of Eta Carinae and implications to massive binaries
Authors: Kashi Amit 
Published: December 2019

AbstractUsing high resolution 3D hydrodynamical simulations we quantify the amount of mass accreted onto the secondary star of the binary system η Carinae during periastron passage on its highly eccentric orbit. The accreted mass is responsible for the spectroscopic event occurring every orbit close to periastron passage, during which many lines vary and the x-ray emission associated with the destruction wind collision structure declines. The system is mainly known for its giant eruptions that occurred in the nineteenth century. The high mass model of the system, M1=170M⊙ and M2=80M⊙, gives Macc≍ 3×10−6M⊙ compatible with the amount required for explaining the reduction in secondary ionization photons during the spectroscopic event, and also matches its observed duration. As accretion occurs now, it surely occurred during the giant eruptions. This implies that mass transfer can have a huge influence on the evolution of massive stars.
On the nature of the X-ray outbursts in Be/X-ray binaries
Authors: Yan Jingzhi , Liu Wei , Zhang Peng , Liu Qingzhong 
Published: December 2019

AbstractBe/X-ray binaries are a major subclass of high mass X-ray binaries. Two different X-ray outbursts are displayed in the X-ray light curves of such systems. It is generally believed that the X-ray outbursts are connected with the neutron star periastron passage of the circumstellar disk around the Be star. The optical emission of the Be star should be very important to understand the X-ray emission of the compact object. We have monitored several Be/X-ray binaries photometrically and spectroscopically in the optical band. The relationship between the optical emission and X-ray activity is described, which is very useful to explain the X-ray outbursts in Be/X-ray binaries.
Collaborative Modeling With Fine‐Resolution Data Enhances Flood Awareness, Minimizes Differences in Flood Perception, and Produces Actionable Flood Maps
Authors: Sanders Brett F. , Schubert Jochen E. , Goodrich Kristen A. , Houston Douglas , Feldman David L. , Basolo Victoria , Luke Adam , Boudreau Dani , Karlin Beth , Cheung Wing , Contreras Santina , Reyes Abigail , Eguiarte Ana , Serrano Kimberly , Allaire Maura , Moftakhari Hamed , AghaKouchak Amir , Matthew Richard A. 
Published: December 2019

AbstractExisting needs to manage flood risk in the United States are underserved by available flood hazard information. This contributes to an alarming escalation of flood impacts amounting to hundreds of billions of dollars per year and countless disrupted lives and affected communities. Making information about flood hazards useful for the range of decisions that dictate the consequences of flooding poses many challenges. Here, we describe collaborative flood modeling, whereby researchers and end‐users at two coastal sites co‐develop fine‐resolution flood hazard models and maps responsive to decision‐making needs. We find, first of all, that resident perception and awareness of flooding are enhanced more by fine‐resolution depth contour maps than Federal Emergency Management Agency (FEMA) flood hazard classification maps and that viewing fine‐resolution depth contour maps helps to minimize differences in flood perception across subgroups within the community, generating a shared understanding. We also find that collaborative flood modeling supports the engagement of a wide range of end‐users in contemplating the risks of flooding and provides strong evidence that the co‐produced knowledge can be readily adopted and applied for Flood Risk Management (FRM). Overall, collaborative flood modeling advances FRM by providing multiple points of entry for diverse groups of end‐users to contemplate the spatial extent, intensity, timing, chance, and consequences of flooding, thus enabling the web of decision‐making related to flooding to be better informed with the best available science. This transdisciplinary approach emphasizes vulnerability reduction and is complementary to FEMA Flood Insurance Rate Maps used for flood insurance administration.
Bifurcated Region 2 Field‐Aligned Currents Associated With Substorms
Authors: Sangha H. , Milan S. E. , Carter J. A. , Fogg A. R. , Anderson B. J. , Korth H. , Paxton L. J. 
Published: December 2019

AbstractWe analyze the magnetosphere‐ionosphere field‐aligned currents associated with substorms using the Active Magnetosphere and Planetary Electrodynamics Response Experiment. We report a new phenomenon related to substorm onset: the development of a second pair of R2 field‐aligned currents located equatorward of the preexisting R1/R2 currents, especially in the dusk sector. The appearance of such events favors the summer hemisphere, suggesting that ionospheric conductance modulates this phenomenon. During ongoing geomagnetic activity, the events have a quasiperiodicity of approximately 1 hr. We suggest that this phenomenon is related to subauroral polarization streams, which are strong westward flows in the dusk sector midlatitude ionosphere. This paper proposes a new mechanism that describes the formation of these current bifurcations: Consecutive particle injections into the inner magnetosphere during disturbed geomagnetic conditions cause separate partial ring currents to form, leading to the presence of distinct R2 current systems, all flowing into the R1 current.
Radial Evolution of Coronal Mass Ejections Between MESSENGER, Venus Express, STEREO, and L1: Catalog and Analysis
Authors: Salman T. M. , Winslow R. M. , Lugaz N. 
Published: December 2019

AbstractOur knowledge of the properties of coronal mass ejections (CMEs) in the inner heliosphere is constrained by the relative lack of plasma observations between the Sun and 1 AU. In this work, we present a comprehensive catalog of 47 CMEs measured in situ measurements by two or more radially aligned spacecraft (MESSENGER, Venus Express, STEREO, Wind/ACE). We estimate the CME impact speeds at Mercury and Venus using a drag‐based model and present an average propagation profile of CMEs (speed and deceleration/acceleration) in the inner heliosphere. We find that CME deceleration continues past Mercury's orbit but most of the deceleration occurs between the Sun and Mercury. We examine the exponential decrease of the maximum magnetic field strength in the CME with heliocentric distance using two approaches: a modified statistical method and analysis from individual conjunction events. Findings from both the approaches are on average consistent with previous studies but show significant event‐to‐event variability. We also find the expansion of the CME sheath to be well fit by a linear function. However, we observe the average sheath duration and its increase to be fairly independent of the initial CME speed, contradicting commonly held knowledge that slower CMEs drive larger sheaths. We also present an analysis of the 3 November 2011 CME observed in longitudinal conjunction between MESSENGER, Venus Express, and STEREO‐B focusing on the expansion of the CME and its correlation with the exponential falloff of the maximum magnetic field strength in the ejecta.
Identifying Radiation Belt Electron Source and Loss Processes by Assimilating Spacecraft Data in a Three‐Dimensional Diffusion Model
Authors: Cervantes S. , Shprits Y. Y. , Aseev N. A. , Drozdov A. Y. , Castillo A. , Stolle C. 
Published: December 2019

AbstractData assimilation aims to blend incomplete and inaccurate data with physics‐based dynamical models. In the Earth's radiation belts, it is used to reconstruct electron phase space density, and it has become an increasingly important tool in validating our current understanding of radiation belt dynamics, identifying new physical processes, and predicting the near‐Earth hazardous radiation environment. In this study, we perform reanalysis of the sparse measurements from four spacecraft using the three‐dimensional Versatile Electron Radiation Belt diffusion model and a split‐operator Kalman filter over a 6‐month period from 1 October 2012 to 1 April 2013. In comparison to previous works, our 3‐D model accounts for more physical processes, namely, mixed pitch angle‐energy diffusion, scattering by Electromagnetic Ion Cyclotron waves, and magnetopause shadowing. We describe how data assimilation, by means of the innovation vector, can be used to account for missing physics in the model. We use this method to identify the radial distances from the Earth and the geomagnetic conditions where our model is inconsistent with the measured phase space density for different values of the invariants
and
. As a result, the Kalman filter adjusts the predictions in order to match the observations, and we interpret this as evidence of where and when additional source or loss processes are active. The current work demonstrates that 3‐D data assimilation provides a comprehensive picture of the radiation belt electrons and is a crucial step toward performing reanalysis using measurements from ongoing and future missions.
Numerical Modeling of Mantle Flow Beneath Madagascar to Constrain Upper Mantle Rheology Beneath Continental Regions
Authors: Rajaonarison T. A. , Stamps D. S. , Fishwick S. , Brune S. , Glerum A. , Hu J. 
Published: December 2019

AbstractOver the past few decades, azimuthal seismic anisotropy measurements have been widely used proxy to study past and present‐day deformation of the lithosphere and to characterize convection in the mantle. Beneath continental regions, distinguishing between shallow and deep sources of anisotropy remains difficult due to poor depth constraints of measurements and a lack of regional‐scale geodynamic modeling. Here, we constrain the sources of seismic anisotropy beneath Madagascar where a complex pattern cannot be explained by a single process such as absolute plate motion, global mantle flow, or geology. We test the hypotheses that either Edge‐Driven Convection (EDC) or mantle flow derived from mantle wind interactions with lithospheric topography is the dominant source of anisotropy beneath Madagascar. We, therefore, simulate two sets of mantle convection models using regional‐scale 3‐D computational modeling. We then calculate Lattice Preferred Orientation that develops along pathlines of the mantle flow models and use them to calculate synthetic splitting parameters. Comparison of predicted with observed seismic anisotropy shows a good fit in northern and southern Madagascar for the EDC model, but the mantle wind case only fits well in northern Madagascar. This result suggests the dominant control of the measured anisotropy may be from EDC, but the role of localized fossil anisotropy in narrow shear zones cannot be ruled out in southern Madagascar. Our results suggest that the asthenosphere beneath northern and southern Madagascar is dominated by dislocation creep. Dislocation creep rheology may be dominant in the upper asthenosphere beneath other regions of continental lithosphere.
Multispecies Assessment of Factors Influencing Regional CO2 and CH4 Enhancements During the Winter 2017 ACT‐America Campaign
Authors: Baier Bianca C. , Sweeney Colm , Choi Yonghoon , Davis Kenneth J. , DiGangi Joshua P. , Feng Sha , Fried Alan , Halliday Hannah , Higgs Jack , Lauvaux Thomas , Miller Benjamin R. , Montzka Stephen A. , Newberger Timothy , Nowak John B. , Patra Prabir , Richter Dirk , Walega James , Weibring Petter 
Published: December 2019

AbstractDiagnosing carbon dioxide (CO2) and methane (CH4) fluxes at subcontinental scales is complicated by sparse observations, limited knowledge of prior fluxes and their uncertainties, and background and transport errors. Multispecies measurements in flasks sampled during the wintertime ACT‐America campaign were used for background characterization and source apportionment of regional anthropogenic CO2 and CH4 fluxes when ecosystem CO2 exchange is likely to be least active. Continental background trace gas mole fractions for regional enhancements are defined using samples from the upper troposphere and assessed using model products. Trace gas enhancements taken from flask samples in the lower troposphere with background levels subtracted out are then interpreted to inform CO2 and CH4 enhancement variability in the eastern United States. Strong correlations between CO2 and CH4 enhancements in the Midwestern and Mid‐Atlantic United States indicated colocated anthropogenic sources. Oil and natural gas influence was also broadly observed throughout the entire observational domain. In the Midwestern United States, agricultural influence on CO2 and CH4 enhancement variability was evident during above‐average wintertime temperatures. Weaker correlations between CO2 and anthropogenic tracer enhancements in the Southeastern United States indicated potentially nonnegligible wintertime ecosystem CO2 exchange, with biogenic tracers indicating more active surface processing than other regions. These whole‐air flask samples illuminated significant regional CO2 and CH4 sources or sinks during Atmospheric Carbon and Transport‐America (ACT‐America) and can provide additional information for informing regional inverse modeling efforts.
Exploring Oxidation in the Remote Free Troposphere: Insights From Atmospheric Tomography (ATom)
Authors: Brune W. H. , Miller D. O. , Thames A. B. , Allen H. M. , Apel E. C. , Blake D. R. , Bui T. P. , Commane R. , Crounse J. D. , Daube B. C. , Diskin G. S. , DiGangi J. P. , Elkins J. W. , Hall S. R. , Hanisco T. F. , Hannun R. A. , Hintsa E. J. , Hornbrook R. S. , Kim M. J. , McKain K. , Moore F. L. , Neuman J. A. , Nicely J. M. , Peischl J. , Ryerson T. B. , St. Clair J. M. , Sweeney C. , Teng A. P. , Thompson C. , Ullmann K. , Veres P. R. , Wennberg P. O. , Wolfe G. M. 
Published: December 2019

AbstractEarth's atmosphere oxidizes the greenhouse gas methane and other gases, thus determining their lifetimes and oxidation products. Much of this oxidation occurs in the remote, relatively clean free troposphere above the planetary boundary layer, where the oxidation chemistry is thought to be much simpler and better understood than it is in urban regions or forests. The NASA airborne Atmospheric Tomography study (ATom) was designed to produce cross sections of the detailed atmospheric composition in the remote atmosphere over the Pacific and Atlantic Oceans during four seasons. As part of the extensive ATom data set, measurements of the atmosphere's primary oxidant, hydroxyl (OH), and hydroperoxyl (HO2) are compared to a photochemical box model to test the oxidation chemistry. Generally, observed and modeled median OH and HO2 agree to within combined uncertainties at the 2σ confidence level, which is ~±40%. For some seasons, this agreement is within ~±20% below 6‐km altitude. While this test finds no significant differences, OH observations increasingly exceeded modeled values at altitudes above 8 km, becoming ~35% greater, which is near the combined uncertainties. Measurement uncertainty and possible unknown measurement errors complicate tests for unknown chemistry or incorrect reaction rate coefficients that would substantially affect the OH and HO2 abundances. Future analysis of detailed comparisons may yield additional discrepancies that are masked in the median values.
Fate of Organic Carbon Burial in Modern Sediment Within Yangtze River Estuary
Authors: Sun Xueshi , Fan Dejiang , Liao Huijie , Tian Yuan 
Published: December 2019

AbstractLarge river‐dominated margins play a potential key role in regulating global carbon cycle and budget due to high terrestrial organic carbon (Corg) inputs and sediment accumulation rates. Here bulk elements (Corg and TN), isotopic compositions (δ13Corg and δ15N), radioisotope 210Pb, sedimentary grain size, pH, Eh, and physicochemical properties were analyzed on samples from the Yangtze River Estuary to determine the mechanism involved in transporting sedimentary Corg offshore. In addition, nine box‐cores were analyzed to further reveal the potential effects of the declining sediment load on the modern depositional pattern of Corg. The statistical analyses indicate that the hydrodynamically driven sediment composition exerts a significant control on the transport, mobilization, and accumulation of sedimentary Corg from the river to the estuary, with respect to the redistribution of fine‐grained sediments. Furthermore, X‐radiographs and 210Pb indicate that reworked environment dominates carbon burial in the Yangtze proximal deposit, while a stable sedimentary environment of Corg (3.50–5.58 g cm−2 year−1) is observed in the Yangtze distal mud. Notably, the enhanced erosional inputs that contain terrestrial plant debris (mainly the coarse fractions) have tended to become important sources for Corg. Although reworked sediments in the Yangtze River Estuary are frequently exposed to oxygen during physical and biological processes, there appears to be a high potential for long‐term sedimentary Corg storage, due to its association with sediment particles (mainly the clay fractions) that provide physical protection against its degradation.
Some Experiments in Extreme‐Value Statistical Modeling of Magnetic Superstorm Intensities
Authors: Love Jeffrey J. 
Published: December 2019

AbstractIn support of projects for forecasting and mitigating the deleterious effects of extreme space weather storms, an examination is made of the intensities of magnetic superstorms recorded in the
index time series (1957–2016). Modified peak‐over‐threshold and solar cycle, block‐maximum samplings of the
time series are performed to obtain compilations of storm maximum
intensity values. Lognormal, upper limit lognormal, generalized Pareto, and generalized extreme‐value model distributions are fitted to the
data using a maximum‐likelihood algorithm. All four candidate models provide good representations of the data. Comparisons of the statistical significance and goodness of fits of the various models give no clear indication as to which model is best. The statistical models are used to extrapolate to extreme‐value intensities, such as would be expected (on average) to occur once per century. An upper limit lognormal fit to peak‐over‐threshold
data above a superstorm threshold of 283 nT gives a 100‐year extrapolated intensity of 542 nT and a 68% confidence interval (obtained by bootstrap resampling) of [466, 583] nT. A generalized extreme‐value distribution fit to solar cycle, block‐maximum
data gives a nine‐solar cycle (approximately 100‐year) extrapolated intensity of 591 nT. The
data are found to be insufficient for providing usefully accurate estimates of a statistically theoretical upper limit for magnetic storm intensity. Secular change in storm intensities is noted, as is a need for improved estimates of pre‐1957 magnetic storm intensities.
Ultrafast electrical switching of nanostructured metadevice with dual-frequency liquid crystal
Authors: Kowerdziej Rafał , Wróbel Jerzy , Kula Przemysław 
Published: December 2019

AbstractShortening of switching times of various soft-matter-based tunable metamaterials is one of the key challenges to improve the functionality of modern active devices. Here we show an effective strategy in the evolution of soft-matter-based tunable metamaterials that makes possible acceleration of both on and off switching processes by using a dual-frequency liquid crystal mixture. The frequency-convertible dielectric anisotropy of the dual-frequency mixture enabled us to create a fast-response in-plane switching metasurface at the nanoscale, which could be tuned by an electrical signal with different frequencies. The results clearly show that the resonance of the metamaterial can be continuously and reversibly controlled within a wavelength range of 100 nm as the applied frequency is inverted between 1 kHz and 40 kHz, with a total response time (τ = τON + τOFF) of 1.89 ms. Furthermore, experimental characteristics of the hybrid metamaterial are in great agreement with numerical calculations, which allow us to anticipate active epsilon-near-zero behavior of the metadevice. This work indicates the future development direction of liquid-crystal-based active plasmonic systems.
An Efficient Intestinal Organoid System of Direct Sorting to Evaluate Stem Cell Competition in Vitro
Authors: Fujimichi Yuki , Otsuka Kensuke , Tomita Masanori , Iwasaki Toshiyasu 
Published: December 2019

AbstractStem cell competition could shed light on the tissue-based quality control mechanism that prevents carcinogenesis. To quantitatively evaluate stem cell competition in vitro, we developed a two-color intestinal organoid forming system. First, we improved a protocol of culturing organoids from intestinal leucine-rich-repeat containing G-protein-coupled receptor 5 (Lgr5)- enhanced green fluorescent protein (EGFP)high stem cells directly sorted on Matrigel without embedding. The organoid-forming potential (OFP) was 25% of Lgr5-EGFPhigh cells sorted at one cell per well. Using this culture protocol with lineage tracing, we established a two-color organoid culture system by mixing stem cells expressing different fluorescent colors. To analyze stem cell competition, two-color organoids were formed by mixing X-ray-irradiated and non-irradiated intestinal stem cells. In the two-color organoids, irradiated stem cells exhibited a growth disadvantage, although the OFP of irradiated cells alone did not decrease significantly from that of non-irradiated cells. These results suggest that stem cell competition can be evaluated quantitively in vitro using our new system.
Characterization and functional roles of paternal RNAs in 2–4 cell bovine embryos
Authors: Gross Nicole , Strillacci Maria Giuseppina , Peñagaricano Francisco , Khatib Hasan 
Published: December 2019

AbstractEmbryos utilize oocyte-donated RNAs until they become capable of producing RNAs through embryonic genome activation (EGA). The sperm’s influence over pre-EGA RNA content of embryos remains unknown. Recent studies have revealed that sperm donate non-genomic components upon fertilization. Thus, sperm may also contribute to RNA presence in pre-EGA embryos. The first objective of this study was to investigate whether male fertility status is associated with the RNAs present in the bovine embryo prior to EGA. A total of 65 RNAs were found to be differentially expressed between 2–4 cell bovine embryos derived from high and low fertility sires. Expression patterns were confirmed for protein phosphatase 1 regulatory subunit 36 (PPP1R36) and ataxin 2 like (ATXN2L) in three new biological replicates. The knockdown of ATXN2L led to a 22.9% increase in blastocyst development. The second objective of this study was to characterize the parental origin of RNAs present in pre-EGA embryos. Results revealed 472 sperm-derived RNAs, 2575 oocyte-derived RNAs, 2675 RNAs derived from both sperm and oocytes, and 663 embryo-exclusive RNAs. This study uncovers an association of male fertility with developmentally impactful RNAs in 2–4 cell embryos. This study also provides an initial characterization of paternally-contributed RNAs to pre-EGA embryos. Furthermore, a subset of 2–4 cell embryo-specific RNAs was identified.