bluuebunny/crossref_metadata_2025_split huggingface dataset:
Upper Crustal Structure and Magmatism in Southwest Washington: Vp, Vs, and Vp/Vs Results From the iMUSH Active‐Source Seismic Experiment
Authors: Kiser E. , Levander A. , Zelt C. , Schmandt B. , Hansen S. 
Published: July 2019

AbstractStructural details of the crust play an important role in controlling the distribution of volcanic activity in arc systems. In southwest Washington, several different regional structures associated with accretion and magmatism have been invoked to explain the broad distribution of Cascade volcanism in this region. In order to image these regional structures in the upper crust, Pg and Sg travel times from the imaging Magma Under St. Helens (iMUSH) active‐source seismic experiment are inverted for Vp, Vs, and Vp/Vs models in the region surrounding Mount St. Helens. Several features of these models provide new insights into the regional structure of the upper crust. A large section of the Southern Washington Cascades Conductor is imaged as a low Vp/Vs anomaly that is inferred to represent a broad sedimentary/metasedimentary sequence that composes the upper crust in this region. The accreted terrane Siletzia is imaged west of Mount St. Helens as north/south trending high Vp and Vp/Vs bodies. The Vp/Vs model shows relatively high Vp/Vs regions near Mount St. Helens and the Indian Heaven Volcanic Field, which could be related to the presence of magmatic fluids. Separating these two volcanic regions below 6‐km depth is a northeast trending series of high Vp and Vs bodies. These bodies have the same orientation as several volcanic/magmatic features at the surface, including Mount St. Helens and Mount Rainier, and it is argued that these high‐velocity features are a regional‐scale group of intrusive bodies associated with a crustal weak zone that focuses magma ascent.
Impact of Radar Data Sampling on the Accuracy of Atmospheric Refractivity Inversions Over Marine Surfaces
Authors: Matsko I. J. , Hackett E. E. 
Published: July 2019

AbstractThe turbulent nature of the marine atmospheric boundary layer and interactions across the air‐sea interface cause ever‐changing environmental conditions, including atmospheric properties that affect the index of refraction, or atmospheric refractivity. Variations in atmospheric refractivity lead to many types of anomalous propagation phenomena of electromagnetic (EM) signals; thus, improving performance of EM systems requires in situ knowledge of the refractivity. Inversion approaches to estimate refractivity rely on measured EM data; however, despite its importance, few studies have examined the influence of data density on the accuracy of refractivity inversions. This study applies a bistatic radar data inversion process to estimate atmospheric refractivity parameters in evaporative ducting conditions and examines the impacts of the sampling density of radar propagation loss data, and its source location, on accuracy of refractivity inversions. Genetic algorithms and a radar propagation model are used to perform the inversions. Numerical experiments examine various randomly distributed amounts of synthetic data from a 100‐m (altitude) by 60‐km (range) area. Three domains within this area are examined from which data were sourced. A data density of approximately 1% of the prediction domain yielded the smallest errors of refractivity parameters, and root mean square errors of refractivity and propagation loss. These error reductions are attributed to avoidance of nonunique solutions that likely impact lower data densities, supported by their classification as a misleading or difficult inverse problem. Generally, data sourced from long range result in lower refractivity and propagation loss root mean square errors compared to data sourced from other domains.
Analytical Solution of Gas Flow in Rough‐Walled Microfracture at In Situ Conditions
Authors: Wang Junjian , Tang Dazhen , Jing Yu 
Published: July 2019

AbstractThe development of the unconventional gas and CO2 sequestration is moving to deep formations. Because of the small flow pathways in the matrix, the Knudsen number might be high even though the gas is dense. In fact, due to the relatively high pressure at in situ conditions, gas flow in microfractures usually manifests a strong slip and nonideal gas effects. Therefore, understanding the coupling mechanism of these two on gas flow in rough‐walled microfractures is required to accurately model subsurface flow behavior. In this study, pressure‐driven gas flow in rough‐walled microfracture is analyzed in depth. Starting from the local governing equations for gas flow, a local flow model that includes gas slip and nonideal gas effects is derived by solving the Stokes equation with a first‐order slip boundary condition. Focusing at the representative elementary volume scale, the upscaled solutions to gas flow in a fracture with sinusoidal surface are derived to obtain the apparent permeability. The impact of nonideal gas effects, fracture roughness and aperture, and the tangential momentum accommodation coefficient on CH4 and CO2 flow is analyzed. The results show that fracture roughness introduces a high degree of heterogeneity in gas flow. At in situ conditions effects of gas slip, fracture roughness and tangential momentum accommodation coefficient on gas flow are reduced. The ideal gas law is capable of estimating CH4 flow to some extent. However, it fails to estimate CO2 flow in microfractures.
Predictability of Weather and Climate
Authors: Krishnamurthy V. 
Published: July 2019

AbstractThe past developments in the predictability of weather and climate are discussed from the point of view of nonlinear dynamical systems. The problems ahead for long‐range predictability extending into the climate time scale are also presented. The sensitive dependence of chaos on initial conditions and the imperfections in the models limit reliable predictability of the instantaneous state of the weather to less than 10 days in present‐day operational forecasts. The existence of slowly varying components such as the sea surface temperature, soil moisture, snow cover, and sea ice may provide basis for predicting certain aspects of climate at long range. The regularly varying nonlinear oscillations, such as the Madden‐Julian Oscillation, monsoon intraseasonal oscillations, and El Niño‐Southern Oscillation, are also possible sources of extended‐range predictability at the climate time scale. A prediction model based on phase space reconstruction has demonstrated that monsoon intraseasonal oscillation can be better predicted at long leads.
Stepwise Weakening of the Pliocene Leeuwin Current
Authors: De Vleeschouwer David , Petrick Benjamin F. , Martínez‐García Alfredo 
Published: July 2019

AbstractThe Indonesian Throughflow (ITF) operates as an important link in global thermohaline circulation, and ITF variability probably modulated Pliocene climate change. Yet, whether ITF variability accounted for oceanographic change south of Northwest Cape remains controversial. Here, we present a multiproxy oceanographic reconstruction from the Perth Basin and reconstruct the Pliocene history of the Leeuwin Current (LC). We show that the LC was active throughout the Pliocene, albeit with fluctuations in intensity and scope. Three main factors controlled LC strength. First, a tectonic ITF reorganization caused an abrupt and permanent LC reduction at 3.7 Ma. On shorter timescales, eustatic sea level and direct orbital forcing of wind patterns hampered or promoted the LC. At 3.3 Ma, for instance, LC intensity plunged in response to a eustatic ITF restriction. Site U1459 then fell outside the extent of a weakened LC, and the latitudinal sea surface temperature gradient along West Australia doubled its steepness.
Effects of Preexisting Structures on the Seismicity of the Charlevoix Seismic Zone
Authors: Fadugba Oluwaseun Idowu , Choi Eunseo , Powell Christine A. 
Published: July 2019

AbstractThe Charlevoix Seismic Zone (CSZ) is located along the early Paleozoic St. Lawrence rift zone in southeastern Quebec at the location of a major Devonian impact structure. The impact structure superimposed major, steeply dipping basement faults trending approximately N35°E. Approximately 250 earthquakes are recorded each year and are concentrated within and beneath the impact structure. Most M4+ earthquakes associated with the rift faults occurred outside the impact structure. Apart from the unique distribution of earthquakes, stress inversion of focal mechanisms shows stress rotations within the CSZ, and in the CSZ relative to the stress orientation determined from borehole breakouts. The primary goal of this research is to investigate the combined effects of the preexisting structures and regional stresses on earthquake activity and stress rotations in the CSZ. We approach this using PyLith, a finite‐element code for simulations of crustal deformation. Adopting the results from recent hypocenter relocation and 3‐D tomography studies, we modify the locations and dips of the rift faults and assess the effect of the new fault geometries on stress distributions. We also discuss the effects of resolved velocity anomalies. We find that the observed stress rotation is due to the combined effect of the rift faults and the impact structure. One‐dimensional velocity models of the CSZ with an embedded impact structure and a combination of 65°‐40°‐40° and constant 70° fault dip models with a very low friction coefficient of 0.3 and cohesion of 0 MPa can explain the observed seismicity and more than 50% of the stress rotations.
On the High‐Energy Spectral Component and Fine Time Structure of Terrestrial Gamma Ray Flashes
Authors: Marisaldi M. , Galli M. , Labanti C. , Østgaard N. , Sarria D. , Cummer S. A. , Lyu F. , Lindanger A. , Campana R. , Ursi A. , Tavani M. , Fuschino F. , Argan A. , Trois A. , Pittori C. , Verrecchia F. 
Published: July 2019

AbstractTerrestrial gamma ray flashes (TGFs) are very short bursts of gamma radiation associated to thunderstorm activity and are the manifestation of the highest‐energy natural particle acceleration phenomena occurring on Earth. Photon energies up to several tens of megaelectronvolts are expected, but the actual upper limit and high‐energy spectral shape are still open questions. Results published in 2011 by the AGILE team proposed a high‐energy component in TGF spectra extended up to ≈100 MeV, which is difficult to reconcile with the predictions from the Relativistic Runaway Electron Avalanche (RREA) mechanism at the basis of many TGF production models. Here we present a new set of TGFs detected by the AGILE satellite and associated to lightning measurements capable to solve this controversy. Detailed end‐to‐end Monte Carlo simulations and an improved understanding of the instrument performance under high‐flux conditions show that it is possible to explain the observed high‐energy counts by a standard RREA spectrum at the source, provided that the TGF is sufficiently bright and short. We investigate the possibility that single high‐energy counts may be the signature of a fine‐pulsed time structure of TGFs on time scales ≈4 μs, but we find no clear evidence for this. The presented data set and modeling results allow also for explaining the observed TGF distribution in the (Fluence × duration) parameter space and suggest that the AGILE TGF detection rate can almost be doubled.
Introduction to the Special Issue: Ice on Ceres
Authors: Sizemore H. G. , Schmidt B. E. , Castillo‐Rogez J. C. 
Published: July 2019

AbstractCeres is the largest body in the asteroid belt, and the most water‐rich inner solar system body after Earth. Its exploration by the Dawn spacecraft has been long anticipated, in large part because it was expected to be an ice‐rich world. A variety of ice‐ and volatile‐related physical processes were expected to occur on Ceres, including possible cryovolcanism. A major goal of the Dawn mission at Ceres was to understand the abundance, distribution, and phase partitioning of water in the subsurface. Coordinated investigations of subsurface ice during the Dawn mission benefited from the decades‐long effort to inventory and characterize subsurface ice on Mars. Specifically, morphological analysis was leveraged to bridge a length‐scale gap between geophysical remote sensing data sets that provide quantitative constraints on the abundance of subsurface ice at very shallow depths (<1 m; neutron spectroscopy) and data sets that provide quantitative constraints on composition at much longer length scales (tens of kilometers; gravity science). This morphological analysis underscores that Ceres shares geophysical characteristics with terrestrial planets, icy moons, comets, and asteroids, and blurs some of the conventional boundaries between these terms. Grappling with this ambiguity stands to benefit investigations of interior evolution and volatile‐related processes on all solid planetary bodies.
Connecting Fluvial Levee Deposition to Flood‐Basin Hydrology
Authors: Johnston G. H. , David S. R. , Edmonds D. A. 
Published: July 2019

AbstractLevees are commonly found along every kind of river system, yet there are no widely accepted models for where along the channel they form and what controls their shape. In this study, we investigated whether levee growth is driven by sediment transfer from the channel adjacent to the levee or by inundation dynamics in the flood basin. To test these ideas, we conducted empirical analyses and numerical modeling of levees on the fine‐grained, meandering Muscatatuck River, IN. Using LiDAR data, we found no statistical relationship between the levee and the adjacent channel planform, which suggests levees are not genetically related to their adjacent channel. On the contrary, modeling experiments of a simplified Muscatatuck River show that levee initiation can be genetically related to the adjacent channel because bed shear stress on the floodplain is low where channel curvature is high. But after levees initiate, the genetic connection to the adjacent channel is obscured because levee shape is modified by inundation dynamics. For instance, tall mature levees are not inundated regularly and instead obstruct floodplain flow, creating flow shadows on the downstream side. Sediment is preferentially deposited in the flow shadow, which moves the location of maximum deposition from the levee crest to the toe. This causes levees to prograde down‐valley, which reshapes the levee and genetically disconnects it from the channel. We propose that this morphodynamic mechanism of levee growth is characteristic of fine‐grained rivers in narrow floodplains where flood basins can act as conveyance channels that transport sediment down‐valley before deposition.
Footwall Rotation in a Regional Detachment Fault System: Evidence for Horizontal‐Axis Rotational Flow in the Miocene Searchlight Pluton, NV
Authors: Zuza Andrew V. , Cao Wenrong , Hinz Nicholas H. , DesOrmeau Joel W. , Odlum Margaret L. , Stockli Daniel F. 
Published: July 2019

AbstractThe Miocene Searchlight pluton, exposed in the Colorado River Extensional Corridor of southern Nevada, tilted up to 90° on its side in the footwall of the east‐directed Dupont Mountain detachment fault system. Rapid extension and rotation occurred immediately after the ca. 17–16‐Ma emplacement of this 10 × 10‐km granite‐monzogranite body. To constrain the mechanism and timing of rapid footwall exhumation, we conducted detailed field, microstructural, electron backscatter diffraction, and zircon (U‐Th)/He (ZHe) and40Ar/39Ar hornblende thermochronological analyses. Steeply dipping fabrics across this pluton formed over a range of temperature conditions, from magmatic to high‐ to low‐temperature subsolidus strain, and display distributed eastside‐up shear. ZHe cooling ages are consistent with constraints from tilted volcanic strata and crosscutting dikes that suggest initial rapid rotation (~75°/Myr) at 16.2–15.7 Ma followed by more modest exhumation rates until ca. 13 Ma. Our observations are used to test tilting models for the Searchlight pluton, including rigid‐body rotation, antithetic imbrication, or flow‐like rotation. Available observations are most consistent with a flow‐like tilting mechanism. We present scaling analyses that highlight how footwall tilting‐dominated extension more effectively cools the upper crust than pure‐shear extension because the hottest deep materials exhumed rapidly toward the cooler surface. This extensional mechanism efficiently cools the upper crust, causing a negative feedback whereby the rapidly cooled crust becomes strong enough to halt further fast simple‐shear extension. This may explain why rapid extension was transient and further extension is mostly accommodated by high‐angle low‐offset magnitude normal faults that developed in a colder stronger crust.
Neurons in primary auditory cortex represent sound source location in a cue-invariant manner
Authors: Wood Katherine C. , Town Stephen M. , Bizley Jennifer K. 
Published: July 2019

AbstractAuditory cortex is required for sound localisation, but how neural firing in auditory cortex underlies our perception of sound sources in space remains unclear. Specifically, whether neurons in auditory cortex represent spatial cues or an integrated representation of auditory space across cues is not known. Here, we measured the spatial receptive fields of neurons in primary auditory cortex (A1) while ferrets performed a relative localisation task. Manipulating the availability of binaural and spectral localisation cues had little impact on ferrets’ performance, or on neural spatial tuning. A subpopulation of neurons encoded spatial position consistently across localisation cue type. Furthermore, neural firing pattern decoders outperformed two-channel model decoders using population activity. Together, these observations suggest that A1 encodes the location of sound sources, as opposed to spatial cue values.
A metal–organic framework for efficient water-based ultra-low-temperature-driven cooling
Authors: Lenzen Dirk , Zhao Jingjing , Ernst Sebastian-Johannes , Wahiduzzaman Mohammad , Ken Inge A. , Fröhlich Dominik , Xu Hongyi , Bart Hans-Jörg , Janiak Christoph , Henninger Stefan , Maurin Guillaume , Zou Xiaodong , Stock Norbert 
Published: July 2019

AbstractEfficient use of energy for cooling applications is a very important and challenging field in science. Ultra-low temperature actuated (Tdriving < 80 °C) adsorption-driven chillers (ADCs) with water as the cooling agent are one environmentally benign option. The nanoscale metal-organic framework [Al(OH)(C6H2O4S)] denoted CAU-23 was discovered that possess favorable properties, including water adsorption capacity of 0.37 gH2O/gsorbent around p/p0 = 0.3 and cycling stability of at least 5000 cycles. Most importantly the material has a driving temperature down to 60 °C, which allows for the exploitation of yet mostly unused temperature sources and a more efficient use of energy. These exceptional properties are due to its unique crystal structure, which was unequivocally elucidated by single crystal electron diffraction. Monte Carlo simulations were performed to reveal the water adsorption mechanism at the atomic level. With its green synthesis, CAU-23 is an ideal material to realize ultra-low temperature driven ADC devices.
A genome-wide scan statistic framework for whole-genome sequence data analysis
Authors: He Zihuai , Xu Bin , Buxbaum Joseph , Ionita-Laza Iuliana 
Published: July 2019

AbstractThe analysis of whole-genome sequencing studies is challenging due to the large number of noncoding rare variants, our limited understanding of their functional effects, and the lack of natural units for testing. Here we propose a scan statistic framework, WGScan, to simultaneously detect the existence, and estimate the locations of association signals at genome-wide scale. WGScan can analytically estimate the significance threshold for a whole-genome scan; utilize summary statistics for a meta-analysis; incorporate functional annotations for enhanced discoveries in noncoding regions; and enable enrichment analyses using genome-wide summary statistics. Based on the analysis of whole genomes of 1,786 phenotypically discordant sibling pairs from the Simons Simplex Collection study for autism spectrum disorders, we derive genome-wide significance thresholds for whole genome sequencing studies and detect significant enrichments of regions showing associations with autism in promoter regions, functional categories related to autism, and enhancers predicted to regulate expression of autism associated genes.
Use of syngeneic cells expressing membrane-bound GM-CSF as an adjuvant to induce antibodies against native multi-pass transmembrane protein
Authors: Huang Chien-Chiao , Cheng Kai-Wen , Hsieh Yuan-Chin , Lin Wen-Wei , Cheng Chiu-Min , Yuan Shyng-Shiou F. , Chen I-Ju , Cheng Yi-An , Lu Yun-Chi , Huang Bo-Cheng , Tung Yi-Ching , Cheng Tian-Lu 
Published: July 2019

AbstractMembrane antigens (mAgs) are important targets for the development of antibody (Ab) drugs. However, native mAgs are not easily prepared, causing difficulties in acquiring functional Abs. In this study, we present a platform in which human mAgs were expressed in native form on cell adjuvants made with membrane-bound cytokines that were then used immunize syngeneic mice directly. The membrane-bound cytokines were used as immune stimulators to enhance specific Ab responses against the desired mAgs. Then, mAgs-expressing xenogeneic cells were used for Ab characterization to reduce non-specific binding. We established cell adjuvants by expressing membrane-bound cytokines (mIL-2, mIL-18, or mGM-CSF) on BALB/3T3 cells, which were effective in stimulating splenocyte proliferation in vitro. We then transiently expressed ecotropic viral integration site 2B (EVI2B) on the adjuvants and used them to directly immunize BALB/c mice. We found that 3T3/mGM-CSF cells stimulated higher specific anti-EVI2B Ab response in the immunized mice than the other cell adjuvants. A G-protein coupled receptor (GPCR), CXCR2, was then transiently expressed on 3T3/mGM-CSF cell adjuvant to immunize mice. The immune serum exhibited relatively higher binding to xenogeneic 293 A/CXCR2 cells than 293 A cells (~3.5-fold). Several hybridoma clones also exhibited selective binding to 293 A/CXCR2 cells. Therefore, the cell adjuvant could preserve the native conformation of mAgs and exhibit anti-mAg Ab stimulatory ability, providing a more convenient and effective method to generate functional Abs, thus possibly accelerating Ab drug development.