bluuebunny/crossref_metadata_2025_split huggingface dataset:
社会网络与商业信用: 基于 “结构洞” 位置的证据
Authors: Chen Yunsen 
Published: May 2015

Abstract
A firm’s social network can provide it with competitive advantage, while its trade credit may reflect the competitiveness of its business operations. Unfortunately, there is a lack of crossover studies looking at both social networks and business credit. This paper investigates the influence of a firm holding different structural hole positions on its trade credit. By defining networks as directors’ interlocking positions and using social network analysis to compute the structural holes, this study demonstrates empirically that firms with more structural holes get more trade credit, thereby enhancing their competitive advantage in the market, and their trade credit-cash sensitivity also decreases. These results hold after controlling for the endogeneity problem and the influence of a network centrality measure. Additional analyses show that the influence of structural hole position on trade credit is more obvious in highly competitive industries and regions that have a higher level of marketisation. Moreover, the effect is found mainly for larger and more mature firms and those situated in a worse information environment, and often manifests during a time of loose monetary policies. The results suggest that the control and information advantages obtained by positioning in structural holes are important in enabling firms to obtain trade credit, which can enhance their competitive advantage. The conclusions contribute to the literature on social network and corporate finance.
Joint inversion for global isotropic and radially anisotropic mantle structure including crustal thickness perturbations
Authors: Chang Sung‐Joon , Ferreira Ana M. G. , Ritsema Jeroen , van Heijst Hendrik J. , Woodhouse John H. 
Published: May 2015

AbstractWe present a new global whole‐mantle model of isotropic and radially anisotropic S velocity structure (SGLOBE‐rani) based on ~43,000,000 surface wave and ~420,000 body wave travel time measurements, which is expanded in spherical harmonic basis functions up to degree 35. We incorporate crustal thickness perturbations as model parameters in the inversions to properly consider crustal effects and suppress the leakage of crustal structure into mantle structure. This is possible since we utilize short‐period group‐velocity data with a period range down to 16 s, which are strongly sensitive to the crust. The isotropic S velocity model shares common features with previous global S velocity models and shows excellent consistency with several high‐resolution upper mantle models. Our anisotropic model also agrees well with previous regional studies. Anomalous features in our anisotropic model are faster SV velocity anomalies along subduction zones at transition zone depths and faster SH velocity beneath slabs in the lower mantle. The derived crustal thickness perturbations also bring potentially important information about the crustal thickness beneath oceanic crusts, which has been difficult to constrain due to poor access compared with continental crusts.
A process‐based investigation into the impact of the Congo basin deforestation on surface climate
Authors: Bell Jean P. , Tompkins Adrian M. , Bouka‐Biona Clobite , Sanda I. Seidou 
Published: May 2015

AbstractThe sensitivity of climate to the loss of the Congo basin rainforest through changes in land cover properties is examined using a regional climate model. The complete removal of the Congo basin rainforest results in a dipole rainfall anomaly pattern, characterized by a decrease (∼−42%) in rainfall over the western Congo and an increase (∼10%) in the basin's eastern part. Three further experiments systematically examine the individual response to the changes in albedo, surface roughness, and evapotranspiration efficiency that accompany deforestation. The increased albedo (∼) caused by the Congo basin rainforest clearance results in cooler and drier climate conditions over the entire basin. The drying is accompanied with a reduction in available surface energy. Reducing evapotranspiration efficiency or roughness length produces similar positive air temperature anomaly patterns. The decreased evapotranspiration efficiency leads to a dipole response in rainfall, similar to that resulting from a reduced surface roughness following Congo basin rainforest clearance. This precipitation anomaly pattern is strongly linked to the change in low‐level water vapor transport, the influence of the Rift valley highlands, and the spatial pattern of water recycling activity. The climate responds linearly to the separate albedo, surface roughness, and evapotranspiration efficiency changes, which can be summed to produce a close approximation to the impact of the full deforestation experiment. It is suggested that the widely contrasting climate responses to deforestation in the literature could be partly due to the relative magnitude of change of the radiative and nonradiative parameterizations in their respective land surface schemes.
The role of foehn in the formation of heavy air pollution events in Urumqi, China
Authors: Li X. , Xia X. , Wang L. , Cai R. , Zhao L. , Feng Z. , Ren Q. , Zhao K. 
Published: May 2015

AbstractThe impact of sandwich foehn on air pollution in Urumqi, a gap town located on the northern lee side of the Tianshan Mountains of China, is analyzed. The results show that during days with high pollution, the boundary layer over the city and the down‐valley area can be divided into a three‐layer structure, with the southeasterly foehn sandwiched between the northwesterly winds on top and the cold air surface pool beneath. The southeasterly foehn at heights between 480 and 2100 m results in a very stable boundary layer structure. In combination with the decoupling between the foehn flow and cold air pool, such boundary layer structure prevents vertical mixing of atmospheric pollutants. In the up‐valley area from the northern lee side flank to the southern urban area, the ground‐based foehn confronts the thermally driven valley breeze and forms a “minifront,” which moves northward in the morning and retreats southward in the afternoon. Although the minifront disappears in the early evening, the wind shear of the mountain breeze between the southern suburb and downtown areas is still remarkable, which is favorable for a convergence line to persist around the city all day long. In this case, air pollutants emitted from the up‐valley and down‐valley areas are transported toward the urban area. Therefore, the air pollutants accumulate daily, leading to the frequent occurrence of heavy pollution events in Urumqi. This indicates that the sandwich foehn plays a critical role in the formation of heavy air pollution events in Urumqi.
Horizontal winds derived from the polar mesospheric cloud images as observed by the CIPS instrument on the AIM satellite
Authors: Rong P. P. , Yue J. , Russell J. M. , Lumpe J. D. , Gong J. , Wu D. L. , Randall C. E. 
Published: May 2015

AbstractA cloud pattern matching technique is applied to polar mesospheric cloud (PMC) images taken by the Cloud Imaging and Particle Size instrument (CIPS) to infer the wind velocities in the mesopause region. CIPS measurements are analyzed to detect patterns that repeat from one orbit to the next but are displaced in location; the displacement provides a measure of the wind velocity. Pattern matching is achieved by resampling the CIPS data to longitude and latitude grids with the grid‐box size forced at ~5 km in both directions. The correlated patterns are searched within a geographic region referred to as a “frame” of ~500 km in longitude × 400 km in latitude. The histograms of the derived velocities indicate that easterly winds prevail, with a mean zonal wind of −20 to −15 m/s. Mean meridional winds are overall small, but in late summer the histogram indicated a poleward wind of ~20–30 m/s. The variability of CIPS cloud albedo on consecutive orbits is also examined at fixed geolocations. The statistical results suggest that ~86% of pairs underwent mean cloud albedo variation of < 50% on consecutive orbits, suggesting a moderate change. It is also found that the correlation of the cloud structures between two consecutive orbits at a fixed location is generally poor. These findings suggest that cloud patterns are subject to wind advection, but the cloud patches are more extended in size than the movement that occurs. Cloud voids are found to be more likely to remain at the same geolocations.
Assimilation of thermodynamic information from advanced infrared sounders under partially cloudy skies for regional NWP
Authors: Wang Pei , Li Jun , Goldberg Mitchell D. , Schmit Timothy J. , Lim Agnes H. N. , Li Zhenglong , Han Hyojin , Li Jinlong , Ackerman Steve A. 
Published: May 2015

AbstractGenerally, only clear‐infrared spectral radiances (not affected by clouds) are assimilated in weather analysis systems. This is due to difficulties in modeling cloudy radiances as well as in observing their vertical structure from space. To take full advantage of the thermodynamic information in advanced infrared (IR) sounder observations requires assimilating radiances from cloud‐contaminated regions. An optimal imager/sounder cloud‐clearing technique has been developed by the Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin‐Madison. This technique can be used to retrieve clear column radiances through combining collocated multiband imager IR clear radiances and the sounder cloudy radiances; no background information is needed in this method. The imager/sounder cloud‐clearing technique is similar to that of the microwave/IR cloud clearing in the derivation of the clear‐sky equivalent radiances. However, it retains the original IR sounder resolution, which is critical for regional numerical weather prediction applications. In this study, we have investigated the assimilation of cloud‐cleared IR sounder radiances using Atmospheric Infrared Sounder (AIRS)/Moderate Resolution Imaging Spectroradiometer for three hurricanes, Sandy (2012), Irene (2011), and Ike (2008). Results show that assimilating additional cloud‐cleared AIRS radiances reduces the 48 and 72 h temperature forecast root‐mean‐square error by 0.1–0.3 K between 300 and 850 hPa. Substantial improvement in reducing track forecasts errors in the range of 10 km to 50 km was achieved.
Dual‐frequency radar Doppler spectral retrieval of rain drop size distributions and entangled dynamics variables
Authors: Tridon F. , Battaglia A. 
Published: May 2015

AbstractA novel technique based on Ka‐W band dual‐wavelength Doppler spectra has been developed for the simultaneous retrieval of binned rain drop size distributions (DSD) and air state parameters like vertical wind and air broadening caused by turbulence and wind shear. The rationale underpinning the method consists in exploiting the peculiar features observed in Doppler spectra caused by the wavelength dependence of scattering and absorption properties. A notional study based on a large data set of DSDs measured by a two‐dimensional video disdrometer demonstrates that the retrieval performs best for small/moderate air broadening spectral width and when mean volume diameters exceed at least 1 mm. The retrieval is also limited to ranges below cloud base and where the signal‐to‐noise ratio of both radars exceed 10 dB, which rules out regions affected by strong attenuation. Broadly speaking, it is applicable to rain rates comprised between roughly 1 and 30 mm h−1. Preliminary retrieval for observations at the Atmospheric Radiation Measurement Southern Great Plains site shows very good agreement with independent reflectivity measurements from a 0.915 GHz wind profiler. The proposed methodology shows great potential in linking microphysics to dynamics in rainfall studies.
Long‐term variations in the dissolved oxygen budget of an urbanized tidal river: The upper Delaware Estuary
Authors: Tomaso Daniel J. , Najjar Raymond G. 
Published: May 2015

AbstractThe dissolved oxygen budget in the upper Delaware Estuary between 1970 and 2014 was inferred from oxygen concentration measurements using a box model approach. The region was found to be a net biogeochemical sink of oxygen, with net oxygen consumption greater in the tidal fresh portion than in the oligohaline portion. Net oxygen consumption decreased from the 1970s to the 1990s by roughly a factor of 2 before increasing slightly in the 2000s. The dramatic decline in oxygen consumption was presumably due to improvements in wastewater treatment, though a comparison with biological oxygen demand measurements in wastewater was equivocal. Nonalgal oxygen consumption (i.e., oxygen consumption due to heterotrophic respiration and nitrification) was computed as the sum of the estimated net oxygen consumption and historical measurements of primary production. Nonalgal oxygen consumption was found to be highly seasonal and positively correlated with temperature, with Q10 values ranging between 1.4 and 2.3. Annual nonalgal oxygen consumption was found to be several times annual primary production. Exchange with the atmosphere is the main process that balances the net oxygen consumption throughout the study region, with advection also an important process in the tidal fresh portion. Decadal scale variability in oxygen concentration, including the recent decline in the 2000s, appears to be mainly driven by biological, not physical, processes.
A new method for direction finding based on Markov random field model
Authors: Ota Mamoru , Kasahara Yoshiya , Goto Yoshitaka 
Published: May 2015

AbstractInvestigating the characteristics of plasma waves observed by scientific satellites in the Earth's plasmasphere/magnetosphere is effective for understanding the mechanisms for generating waves and the plasma environment that influences wave generation and propagation. In particular, finding the propagation directions of waves is important for understanding mechanisms of VLF/ELF waves. To find these directions, the wave distribution function (WDF) method has been proposed. This method is based on the idea that observed signals consist of a number of elementary plane waves that define wave energy density distribution. However, the resulting equations constitute an ill‐posed problem in which a solution is not determined uniquely; hence, an adequate model must be assumed for a solution. Although many models have been proposed, we have to select the most optimum model for the given situation because each model has its own advantages and disadvantages. In the present study, we propose a new method for direction finding of the plasma waves measured by plasma wave receivers. Our method is based on the assumption that the WDF can be represented by a Markov random field model with inference of model parameters performed using a variational Bayesian learning algorithm. Using computer‐generated spectral matrices, we evaluated the performance of the model and compared the results with those obtained from two conventional methods.
Contrasting styles of (U)HP rock exhumation along the Cenozoic Adria‐Europe plate boundary (Western Alps, Calabria, Corsica)
Authors: Malusà Marco G. , Faccenna Claudio , Baldwin Suzanne L. , Fitzgerald Paul G. , Rossetti Federico , Balestrieri Maria Laura , Danišík Martin , Ellero Alessandro , Ottria Giuseppe , Piromallo Claudia 
Published: May 2015

AbstractSince the first discovery of ultrahigh pressure (UHP) rocks 30 years ago in the Western Alps, the mechanisms for exhumation of (U)HP terranes worldwide are still debated. In the western Mediterranean, the presently accepted model of synconvergent exhumation (e.g., the channel‐flow model) is in conflict with parts of the geologic record. We synthesize regional geologic data and present alternative exhumation mechanisms that consider the role of divergence within subduction zones. These mechanisms, i.e., (i) the motion of the upper plate away from the trench and (ii) the rollback of the lower plate, are discussed in detail with particular reference to the Cenozoic Adria‐Europe plate boundary, and along three different transects (Western Alps, Calabria‐Sardinia, and Corsica‐Northern Apennines). In the Western Alps, (U)HP rocks were exhumed from the greatest depth at the rear of the accretionary wedge during motion of the upper plate away from the trench. Exhumation was extremely fast, and associated with very low geothermal gradients. In Calabria, HP rocks were exhumed from shallower depths and at lower rates during rollback of the Adriatic plate, with repeated exhumation pulses progressively younging toward the foreland. Both mechanisms were active to create boundary divergence along the Corsica‐Northern Apennines transect, where European southeastward subduction was progressively replaced along strike by Adriatic northwestward subduction. The tectonic scenario depicted for the Western Alps trench during Eocene exhumation of (U)HP rocks correlates well with present‐day eastern Papua New Guinea, which is presented as a modern analog of the Paleogene Adria‐Europe plate boundary.
Evolution of brown carbon in wildfire plumes
Authors: Forrister Haviland , Liu Jiumeng , Scheuer Eric , Dibb Jack , Ziemba Luke , Thornhill Kenneth L. , Anderson Bruce , Diskin Glenn , Perring Anne E. , Schwarz Joshua P. , Campuzano‐Jost Pedro , Day Douglas A. , Palm Brett B. , Jimenez Jose L. , Nenes Athanasios , Weber Rodney J. 
Published: May 2015

AbstractParticulate brown carbon (BrC) in the atmosphere absorbs light at subvisible wavelengths and has poorly constrained but potentially large climate forcing impacts. BrC from biomass burning has virtually unknown lifecycle and atmospheric stability. Here, BrC emitted from intense wildfires was measured in plumes transported over 2 days from two main fires, during the 2013 NASA SEAC4RS mission. Concurrent measurements of organic aerosol (OA) and black carbon (BC) mass concentration, BC coating thickness, absorption Ångström exponent, and OA oxidation state reveal that the initial BrC emitted from the fires was largely unstable. Using back trajectories to estimate the transport time indicates that BrC aerosol light absorption decayed in the plumes with a half‐life of 9 to 15 h, measured over day and night. Although most BrC was lost within a day, possibly through chemical loss and/or evaporation, the remaining persistent fraction likely determines the background BrC levels most relevant for climate forcing.
Direct observations of the full Dungey convection cycle in the polar ionosphere for southward interplanetary magnetic field conditions
Authors: Zhang Q.‐H. , Lockwood M. , Foster J. C. , Zhang S.‐R. , Zhang B.‐C. , McCrea I. W. , Moen J. , Lester M. , Ruohoniemi J. M. 
Published: May 2015

AbstractTracking the formation and full evolution of polar cap ionization patches in the polar ionosphere, we directly observe the full Dungey convection cycle for southward interplanetary magnetic field (IMF) conditions. This enables us to study how the Dungey cycle influences the patches' evolution. The patches were initially segmented from the dayside storm enhanced density plume at the equatorward edge of the cusp, by the expansion and contraction of the polar cap boundary due to pulsed dayside magnetopause reconnection, as indicated by in situ Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations. Convection led to the patches entering the polar cap and being transported antisunward, while being continuously monitored by the globally distributed arrays of GPS receivers and Super Dual Auroral Radar Network radars. Changes in convection over time resulted in the patches following a range of trajectories, each of which differed somewhat from the classical twin‐cell convection streamlines. Pulsed nightside reconnection, occurring as part of the magnetospheric substorm cycle, modulated the exit of the patches from the polar cap, as confirmed by coordinated observations of the magnetometer at Tromsø and European Incoherent Scatter Tromsø UHF radar. After exiting the polar cap, the patches broke up into a number of plasma blobs and returned sunward in the auroral return flow of the dawn and/or dusk convection cell. The full circulation time was about 3 h.
Spatial distributions of secondary minerals in the Martian meteorite MIL 03346,168 determined by Raman spectroscopic imaging
Authors: Ling Zongcheng , Wang Alian 
Published: May 2015

AbstractMiller Range (MIL) 03346 is a nakhlite meteorite that has been extensively studied due to its unique complex secondary mineral phases and their potential implications for the hydrologic history of Mars. We conducted a set of Raman spectroscopic and Raman imaging studies of MIL 03346,168, focusing on the secondary mineral phases and their spatial distributions, with a goal to better understand the possible processes by which they were generated on Mars. This study revealed three types of calcium sulfates, a solid solution of (K, Na)‐jarosite and two groups of hydrated species with low crystallinity (HSLC) in the veins and/or mesostasis areas of the meteorite. The most abundant Ca‐sulfate is bassanite that suggests two possible paths for its direct precipitation from a Ca‐S‐H2O brine, either having low water activity or with incomplete development (producing bassanite with gypsum microcrystals) on Mars. The second most abundant Ca‐sulfate is soluble γ‐CaSO4 which raises a new question on the origins of this phase in the Martian meteorite, since γ‐CaSO4 readily hydrates in the laboratory but is apparently stable in Atacama Desert. The close spatial relationship of (K, Na)‐jarosite solid solutions with rasvumite (KFe2S3), magnetite, HSLC, and fine‐grained low‐crystallinity alkali feldspar in mesostasis suggests a potential in situ formation of mesostasis jarosite from these Fe‐K,Na‐S‐O‐H2O species.
Predicting the magnetic vectors within coronal mass ejections arriving at Earth: 1. Initial architecture
Authors: Savani N. P. , Vourlidas A. , Szabo A. , Mays M. L. , Richardson I. G. , Thompson B. J. , Pulkkinen A. , Evans R. , Nieves‐Chinchilla T. 
Published: May 2015

AbstractThe process by which the Sun affects the terrestrial environment on short timescales is predominately driven by the amount of magnetic reconnection between the solar wind and Earth's magnetosphere. Reconnection occurs most efficiently when the solar wind magnetic field has a southward component. The most severe impacts are during the arrival of a coronal mass ejection (CME) when the magnetosphere is both compressed and magnetically connected to the heliospheric environment. Unfortunately, forecasting magnetic vectors within coronal mass ejections remain elusive. Here we report how, by combining a statistically robust helicity rule for a CME's solar origin with a simplified flux rope topology, the magnetic vectors within the Earth‐directed segment of a CME can be predicted. In order to test the validity of this proof‐of‐concept architecture for estimating the magnetic vectors within CMEs, a total of eight CME events (between 2010 and 2014) have been investigated. With a focus on the large false alarm of January 2014, this work highlights the importance of including the early evolutionary effects of a CME for forecasting purposes. The angular rotation in the predicted magnetic field closely follows the broad rotational structure seen within the in situ data. This time‐varying field estimate is implemented into a process to quantitatively predict a time‐varying Kp index that is described in detail in paper II. Future statistical work, quantifying the uncertainties in this process, may improve the more heuristic approach used by early forecasting systems.