bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-Energy Transients: Thermonuclear (Type-I) X-Ray Bursts
Authors: Galloway D. K. , Johnston Z. , Goodwin A. , Heger A. 
Published: August 2019

AbstractMany distinct classes of high-energy variability have been observed in astrophysical sources, and over a range of time-scales. The widest range, spanning microseconds to decades, is found in accreting, compact, stellar-mass objects, including neutron stars and black holes. Neutron stars are of particular observational interest as they exhibit surface effects giving rise to phenomena – such as thermonuclear bursts and pulsations – not seen in black holes.This talk reviewed briefly the present understanding of thermonuclear (Type-I) X-ray bursts – events that are powered by an extensive chain of nuclear reactions which in many cases are unique to the environments. Thermonuclear bursts have been exploited over the last few years as an avenue to measure a neutron star’s mass and radius, although the contribution of systematic errors to the measurements remains contentious. We described recent efforts to match burst models to observations better, with a view to resolving some of the astrophysical uncertainties relating to those events. Our efforts have good prospects for providing information that is complementary to nuclear experiments.
Radio Transients in the Era of Multi-Messenger Astrophysics
Authors: Anderson G. E. , Stappers B. W. , Andreoni I. , Caleb M. , Coppejans D. , Corbel S. , Fender R. P. , Giroletti M. , Graham M. L. , Sokolovsky K. V. , Woudt P. A. 
Published: August 2019

AbstractRadio emission from astrophysical transients allows us to derive calorimetry of kinetic feedback and detailed imaging in ways that are not possible at other wavelengths, and as such it forms an important part of the multi-messenger follow-ups of these events. The field is burgeoning, with a renaissance of interest in accretion, stellar explosions and jetted supernovæ, alongside newer classes of phenomena such as fast radio bursts and tidal disruption events. The purpose of this workshop was to discuss the infrastructure and techniques for detecting, identifying and probing radio transients, with a particular focus on how best to exploit transient alerts from multi-messenger facilities. We examined the type of transient alerts those facilities will broadcast, and methods for following them up, such as rapid-response triggering and shadowing. In break-out groups, participants chose a science question related to a particular radio transient type or class and discussed whether the planned transient strategies and observing techniques on the Square Kilometre Array will be adequate to address the particular question. The classes they chose included fast radio bursts, supernovæ, cataclysmic variable and unknown transients. Any proposed adaptation or suggestion was relayed to a panel of experts for further discussion. The second part of the workshop concentrated on the application of long baseline interferometry for detecting and measuring radio transients.
Near-Infrared Observations of OGLE Classical and Type II Cepheid Variables in the LMC
Authors: Bhardwaj A. , Macri L. M. , Kanbur S. M. , Ngeow C.-C. , Singh H. P. 
Published: August 2019

AbstractThis poster presented results from the Large Magellanic Cloud Near-Infrared Synoptic Survey (LMCNISS) for classical and Type II Cepheid variables that were identified in the Optical Gravitational Lensing Experiment (OGLE-III) catalogue. Multi-wavelength time-series data for classical Cepheid variables are used to study light-curve structures as a function of period and wavelength. We exploited a sample of ∼1400 classical and ∼80 Type II Cepheid variables to derive Period–Wesenheit relations that combine both optical and near-infrared data. The new Period–Luminosity and Wesenheit relations were used to estimate distances to several Local-Group galaxies (using classical Cepheids) and to Galactic globular clusters (using Type II Cepheids). By appealing to a statistical framework, we found that fundamental-mode classical Cepheid Period–Luminosity relations are non-linear around 10–18 days at optical and near-IR wavelengths. We also suggested that a non-linear relation provides a better constraint on the Cepheid Period–Luminosity relation in Type Ia Supernovæ host galaxies, though it has a negligible effect on the systematic uncertainties affecting the local measurement of the Hubble constant.
Highly Luminous SNe Associated with GRBs
Authors: Kann D. A. 
Published: August 2019

AbstractThe broad-lined Type Ic Supernovæ (SNe) associated with Gamma-Ray Bursts (GRBs) were long considered the most luminous class as a whole among core-collapse SNe, until the discovery of Superluminous SNe (SLSNe) during the last decade. There are many differences between the two classes, but in recent years events have been discovered which form a link between them. Associated with GRBs but more luminous and hotter, and in one case clearly dissimilar spectrally from any other known GRB-SNe, these sources point the way towards common mechanisms underlying GRBs and SLSNe.
Sparse Spatio-Temporal Imaging of Radio Transients
Authors: Girard J. , Jiang M. , Starck J-L. , Corbel S. 
Published: August 2019

AbstractThe next-generation radio telescopes such as LOFAR and SKA will give access to high time-resolution and high instantaneous sensitivity that can be exploited to study slow and fast transients over the whole radio window. The search for radio transients in large datasets also represents a new signal-processing challenge requiring efficient and robust signal reconstruction algorithms. Using sparse representations and the general ‘compressed sensing’ framework, we developed a 2D–1D algorithm based on the primal-dual splitting method. We have performed our sparse 2D–1D reconstruction on three-dimensional data sets containing either simulated or real radio transients, at various levels of SNR and integration times. This report presents a summary of the current level of performance of our method.
CUT AND GAMMA I: PROPOSITIONAL AND CONSTANT DOMAIN R
Authors: WEISS YALE 
Published: August 2019

AbstractThe main object of this article is to give two novel proofs of the admissibility of Ackermann’s rule (γ) for the propositional relevant logic R. The results are established as corollaries of cut elimination for systems of tableaux for R. Cut elimination, in turn, is established both nonconstructively (as a corollary of completeness) and constructively (using Gentzen-like methods). The extensibility of the techniques is demonstrated by showing that (γ) is admissible for RQ* (R with constant domain quantifiers). The status of the admissibility of (γ) for RQ* was, to the best of the author’s knowledge, an open problem. Further extensions of these results will be explored in the sequel(s).
The Older Finnish Twin Cohort — 45 Years of Follow-up
Authors: Kaprio Jaakko , Bollepalli Sailalitha , Buchwald Jadwiga , Iso-Markku Paula , Korhonen Tellervo , Kovanen Vuokko , Kujala Urho , Laakkonen Eija K. , Latvala Antti , Leskinen Tuija , Lindgren Noora , Ollikainen Miina , Piirtola Maarit , Rantanen Taina , Rinne Juha , Rose Richard J. , Sillanpää Elina , Silventoinen Karri , Sipilä Sarianna , Viljanen Anne , Vuoksimaa Eero , Waller Katja 
Published: August 2019

AbstractThe older Finnish Twin Cohort (FTC) was established in 1974. The baseline survey was in 1975, with two follow-up health surveys in 1981 and 1990. The fourth wave of assessments was done in three parts, with a questionnaire study of twins born during 1945–1957 in 2011–2012, while older twins were interviewed and screened for dementia in two time periods, between 1999 and 2007 for twins born before 1938 and between 2013 and 2017 for twins born in 1938–1944. The content of these wave 4 assessments is described and some initial results are described. In addition, we have invited twin-pairs, based on response to the cohortwide surveys, to participate in detailed in-person studies; these are described briefly together with key results. We also review other projects based on the older FTC and provide information on the biobanking of biosamples and related phenotypes.
Effects of Changes in Nitrogen Availability on Nitrogen Gas Emissions in a Tropical Forest During a Drought
Authors: Almaraz Maya , Groffman Peter M. , Porder Stephen 
Published: August 2019

AbstractAtmospheric nitrogen (N) deposition in tropical forests may increase substantially in coming decades, stimulating a concomitant increase of soil N gas emissions. At the same time, climate change may increase the prevalence of drought, altering the processes that produce these gases (dominantly aerobic nitrification and anaerobic denitrification). This alteration is of particular concern if global changes increase the fraction of N gas released as nitrous oxide (N2O; a greenhouse gas) relative to dinitrogen (N2). To simulate the effects of atmospheric N deposition on the amount and species of soil N gas emissions, we installed fertilized ion exchange resin bags across a hillslope in the Luquillo Experimental Forest of Puerto Rico. Our experiment took place during a severe drought, providing opportunities to consider how N addition and dry soil conditions interact. After 2 months of fertilization, we measured denitrification potential using a denitrification enzyme assay, which utilizes anoxic incubations where N and carbon limitation are relieved and nitrification is inhibited. We also measured N2 and N2O emissions using a Nitrogen Free Air Recirculation Method (NFARM), which quantifies emissions from both nitrification and denitrification. Data from these two methods suggest that N inputs stimulated N2O emissions associated with aerobic nitrification. Our data suggest that soil drying during the drought decreased N2 emissions associated with anaerobic denitrification and changed the spatial patterns of emissions in the landscape. Together these results suggest that, at least during a drought, N inputs increase N2O emissions associated with nitrification, which may represent a positive feedback to climate change.
Soil Organic Carbon Stabilization in the Three Subtropical Forests: Importance of Clay and Metal Oxides
Authors: Yu Mengxiao , Wang Yingping , Jiang Jun , Wang Chen , Zhou Guoyi , Yan Junhua 
Published: August 2019

AbstractField observations show that subtropical forests can accumulate soil organic carbon (SOC) at high rate; however, the key mechanisms of SOC accumulation in subtropical forests remain unclear. Here we selected three typical subtropical forests with soil originated from same parent material under same climate condition in Dinghushan Biosphere Reserve, southern China: coniferous forest, mixed forest, and broadleaved forest with very different rates of SOC accumulation over the last three decades. To quantify the relative importance of physical versus chemical process on SOC stabilization in these forests, we used regression analysis to evaluate the relationship between the soil physical (clay, silt, and sand) and chemical (pH, Fe, and Al oxides) properties and SOC, and explored their respective contributions to SOC stabilization. Results showed that SOC stabilization was more strongly influenced by soil clay fraction through sorptive protection or microaggregate formation with SOC in the coniferous forest (r2 = 0.89, p < 0.05), and by chemical protection through forming organo‐mineral complexes in the mixed or broadleaved forest. Increasing carbon input was likely the main cause for SOC accumulation in the coniferous forest, but was not in the broadleaved forest. The strong linear relationships between SOC and Fe/Al oxides indicate that both the mixed (r2 = 0.63 and 0.57 with Feo and Alo, p < 0.05) and broadleaved forests (r2 = 0.96 and 0.78 with Fed and Alo, p < 0.05) on acid soils in southern China still have a great potential for further carbon sequestration in the future.
Electron Dispersion and Parallel Electron Beam Observed Near the Separatrix
Authors: Bai Shi‐Chen , Shi Quanqi , Zong Qiu‐Gang , Wang Xiaogang , Tian Anmin , Degeling Alexander W. , Yue Chao , Rae I. Jonathan , Pu Zu‐Yin , Fu Suiyan 
Published: August 2019

AbstractThe separatrix region is the region between the separatrix and the reconnection jet. Due to the E×B drift and velocity filter effect in which high‐energy particles with high parallel speed can be seen prior to low‐energy particles along the field line, electrons are separated from ions. The electron dynamics in this region is of interest; however it has not been studied in detail, because of the insufficient resolution of plasma data. We present a slow separatrix crossing event observed by Magnetospheric Multiscale (MMS) satellite constellation on 1 January 2016, from the magnetosheath side with high‐resolution burst mode data. The electron edge and ion edge are clearly distinguished in the separatrix region. Two types of electron dispersion, one with a short duration (~0.3 s) and the other with a longer duration (~13 s) were detected between the electron and ion edges. The rapid dispersion (with small time scale) is mainly in the parallel direction, which might originate from a thin layer with non‐frozen‐in electrons close to the separatrix. The gradual (long time scale) dispersion is seen from parallel to perpendicular directions, which comes from the E×B drift of a curved D‐shape distribution of electrons. The width of the electron diffusion region on the magnetosheath side is estimated based on MMS observation. The observation also reveals an unexpected parallel electron beam outside of the electron edge. Wave‐particle interaction or parallel potential in the inflow region may be responsible for the generation of this electron population.
P and S Wave Tomography Beneath the SE Tibetan Plateau: Evidence for Lithospheric Delamination
Authors: Huang Zhouchuan , Wang Liangshu , Xu Mingjie , Zhao Dapeng , Mi Ning , Yu Dayong 
Published: August 2019

AbstractThe SE Tibetan Plateau is located between the eastern Himalayan syntaxis and the stable Yangtze craton; its tectonic evolution is important for understanding the plateau expansion. However, interactions between the plateau and its adjacent subduction zone and craton are still unclear. In this study, we determine updated high‐resolution P and S wave tomographic models of the crust and upper mantle beneath the SE Tibetan Plateau. We confirmed the existence of a high‐velocity layer in the upper mantle down to 200‐km depth beneath the Sichuan basin, the core of the Yangtze craton, representing the stable cratonic root. Another high‐velocity body is located beneath Burma, reflecting the subducting Indian slab in the upper mantle and possibly the remnant Burman slab in the mantle transition zone. A strong low‐velocity column exists above the high‐velocity body in the transition zone and reaches the Moho under the Tengchong volcano. In addition, we find high‐velocity fragments in the upper mantle beneath the Yangtze craton and northern Indochina, which may reflect delaminated lithosphere beneath the SE Tibetan Plateau. The lithospheric delamination may be closely related to mantle flow extruded from the high plateau and possible thermal upwelling from the lower mantle. Our results provide new insight into the deep interactions between the Tibetan plateau and its surrounding blocks near the SE plateau margin.
Strain Accommodation in the Daliangshan Mountain Area, Southeastern Margin of the Tibetan Plateau
Authors: Rui X. , Stamps D. S. 
Published: August 2019

AbstractThe Xianshuihe‐Xiaojiang fault system (XXFS) plays a crucial role in accommodating relative motions of the south China block and the expanding Tibetan Plateau. Compared to the narrow southern and northern segments of the XXFS, the central section (also referred to as the Daliangshan mountain area) is broader and dissected by a network of faults. Geologic studies suggest that three major NNW trending faults may dominate slip partitioning of more recent faults in this region. However, due to accessibility issues, sparse geodetic studies have constrained geodetic fault slip rates with contradictory results. In this study, we use 17 new Global Navigation Satellite System sites combined with existing solutions to investigate slip partitioning of the region. We derive a tectonic velocity solution, develop a block kinematic model constrained by Euler pole clustering technique, and calculate geodetic fault slip rates to compare with geologic fault slip rates. We confirm that the Anninghe‐Daliangshan sliver (ADS) is a distinct, rigid block, and we resolve a new, rigid Daliangshan‐Yingjing‐Mabian block (DYB). Kinematic modeling predicts long‐term slip rates that suggest both the ADS and the DYB partition (~10.0–12.0 mm/year) relative motion between the Tibetan Plateau and south China block in the central XXFS, reconciling geologic observations. We suggest that both the continuum and microplate deformation patterns are present in our study area, of which the local tectonics is better explained by the microplate model, but scale of the kinematics makes its motion more consistent with the continuum model.
Eikonal Tomography of the Southern California Plate Boundary Region
Authors: Qiu Hongrui , Lin Fan‐Chi , Ben‐Zion Yehuda 
Published: August 2019

AbstractWe use Eikonal tomography to derive phase and group velocities of surface waves for the plate boundary region in Southern California. Seismic noise data in the period range 2 and 20 s recorded in year 2014 by 346 stations with ~1‐ to 30‐km station spacing are analyzed. Rayleigh and Love wave phase travel times are measured using vertical‐vertical and transverse‐transverse noise cross correlations, and group travel times are derived from the phase measurements. Using the Eikonal equation for each location and period, isotropic phase and group velocities and 2‐psi azimuthal anisotropy are determined statistically with measurements from different virtual sources. Starting with the SCEC Community Velocity Model, the observed 2.5‐ to 16‐s isotropic phase and group dispersion curves are jointly inverted on a 0.05° × 0.05° grid to obtain local 1‐D piecewise shear wave velocity (Vs) models. Compared to the starting model, the final results have generally lower Vs in the shallow crust (top 3–10 km), particularly in areas such as basins and fault zones. The results also show clear velocity contrasts across the San Andreas, San Jacinto, Elsinore, and Garlock Faults and suggest that the San Andreas Fault southeast of San Gorgonio Pass is dipping to the northeast. Investigation of the nonuniqueness of the 1‐D Vs inversion suggests that imaging the top 3‐km Vs structure requires either shorter period (≤2 s) surface wave dispersion measurements or other types of data set such as Rayleigh wave ellipticity.
Relationship Between the Change in Size of Tropical Cyclones and Spatial Patterns of Precipitation
Authors: Tsuji Hiroki , Nakajima Kensuke 
Published: August 2019

AbstractThe relationship between the size change of tropical cyclones (TCs) and radial distribution of precipitation was investigated for TCs occuring over the western North Pacific Ocean with satellite observation data. The size of a TC is defined as the radial extent of 15 m s−1 winds (R15). The spatial distribution of precipitation was investigated by extracting two subperiods, which are the size‐increasing period and the size‐stationary period, as determined from R15 evolution. The results show a contrast that during the size‐increasing period, precipitation falls both inside and outside the R15, whereas during the size‐stationary period, it is concentrated near the center of the TC and falls less around and outside R15. This contrast is also confirmed statistically by composite analysis using 64 TC cases. Further analysis reveals that this contrast does not depend on the intensity or the change in intensity of the TC, which indicates that the area of precipitation related to the intensity or intensity change of TCs is different from that related to the size change of TCs. Finally, we examined the radial distribution of inertial stability in TCs and found that precipitation during the size‐stationary period occurs in a region with a higher inertial stability than that which occurs during the size‐increasing period.
The Dependence of Shallow Cumulus Macrophysical Properties on Large‐Scale Meteorology as Observed in ASTER Imagery
Authors: Mieslinger Theresa , Horváth Ákos , Buehler Stefan A. , Sakradzija Mirjana 
Published: August 2019

AbstractThis study identifies meteorological variables that control the macrophysical properties of shallow cumulus cloud fields over the tropical ocean. We use 1,158 high‐resolution Advanced Spaceborn Thermal Emission and Reflection Radiometer (ASTER) images to derive properties of shallow cumuli, such as their size distribution, cloud top heights, fractal dimensions, and spatial organization, as well as cloud amount. The large‐scale meteorology is characterized by the lower‐tropospheric stability, subsidence rate, sea surface temperature, total column water vapor, wind speed, wind shear, and Bowen ratio. The surface wind speed emerges as the most powerful control factor. With increasing wind speed the cloud amount and cloud top heights show a robust increase accompanied by a marked shift in the cloud size distribution toward larger clouds with smoother shapes. These results lend observational support to the deepening response of a wind‐driven marine boundary layer as simulated by large‐eddy models. The other control factors cause smaller changes in the cloud field properties. We find a robust increase in cloud amount with increasing stability and decreasing sea surface temperature, respectively, which confirms a well‐known behavior of marine stratocumulus also for shallow cumulus clouds. Due to the high resolution of cloud images, we are able to study the lower end of the cloud size distribution and find a robust double power law behavior with a scale break at 590 m. We find a variation in the shape of the cloud size distribution with Bowen ratio, qualitatively consistent with modeling results and suggesting the Bowen ratio as a new potential control factor on shallow cumulus clouds.
Temperature‐Driven Bubble Migration as Proxy for Internal Bubble Pressures and Bubble Trapping Function in Ice Cores
Authors: Dadic R. , Schneebeli M. , Wiese M. , Bertler N. A. N. , Salamatin A. N. , Theile T. C. , Alley R. B. , Lipenkov V. Ya. 
Published: August 2019

AbstractIce core data record significant and abrupt past climate changes that are associated with large and rapid changes in atmospheric greenhouse gases, such as methane. Due to the gradual close‐off of gas bubbles and the relatively fast diffusion of gases within the firn column, even a discrete or quick step increase in air composition may be smoothed or integrated in the data; current laboratory analyses of gases consider the mean gas content value across all bubbles in a sample, rather than the content of individual bubbles. The convolution of the distribution of trapping ages with the history of atmospheric composition thus smears the measured gas record in each sample. We developed a nondestructive method to determine pressure distribution in all bubbles in a sample and estimate the shape of the trapping function derived from that bubble pressure distribution and site characteristics. Our method works not only for present conditions but also through varying paleo‐atmospheric conditions, while providing accurate measurements of morphological bubble properties. The method is based on using temperature‐driven air bubble migration as a proxy for the pressure of individual bubbles, which we combine with a model for bubbly ice densification to obtain the gas trapping functions and constrain the age distribution of air bubbles for past conditions, which are preserved at different depths. The trapping functions will help us to obtain a more accurate gas signal in the future that is less attenuated through the age distribution of the gas during the close‐off process.