bluuebunny/crossref_metadata_2025_split huggingface dataset:
Possible stick‐slip behavior before the Rausu landslide inferred from repeating seismic events
Authors: Yamada Masumi , Mori Jim , Matsushi Yuki 
Published: September 2016

AbstractA precursory sequence of repeating earthquakes was recorded before the Rausu landslide in Hokkaido, Japan, on 24 April 2015. There were two seismic sequences with each consisting of very similar waveforms and leading up to significant landslide movements. The nearly identical waveform shapes indicate similar source locations and mechanisms, so repeated events originated on a particular small area. This sequence is interpreted as stick‐slip movement on a small patch leading up to the larger landslide failure. Our observations show that heterogeneous structure, such as asperities on the slip surface, can play an important role in the initiation of landslides, adding a new aspect to the conventional understanding of mechanisms controlling large mass movements.
The permeability of the magnetopause to a multispecies substorm injection of energetic particles
Authors: Westlake J. H. , Cohen I. J. , Mauk B. H. , Anderson B. J. , Mitchell D. G. , Gkioulidou M. , Walsh B. M. , Lanzerotti L. J. , Strangeway R. J. , Russell C. T. 
Published: September 2016

AbstractLeakage of ions from the magnetosphere into the magnetosheath remains an important topic in understanding the plasma physics of Earth's magnetopause and the interaction of the solar wind with the magnetosphere. Here using sophisticated instrumentation from two spacecraft (Radiation Belt Storm Probes Ion Composition Experiment on the Van Allen Probes and Energetic Ion Spectrometer on the Magnetospheric Multiscale) spaced uniquely near and outside the dayside magnetopause, we are able to determine the escape mechanisms for large gyroradii oxygen ions and much smaller gyroradii hydrogen and helium ions. The oxygen ions are entrained on the magnetosphere boundary, while the hydrogen and helium ions appear to escape along reconnected field lines. These results have important implications for not only Earth's magnetosphere but also other solar system magnetospheres.
On the evolution of the κ distribution of protons in the inner heliosheath
Authors: Fahr Hans‐Jörg , Sylla Adama , Fichtner Horst , Scherer Klaus 
Published: September 2016

AbstractThe evolution of the solar wind proton distribution function along the plasma flow downstream of the heliospheric termination shock is studied. Starting from a kinetic phase space transport equation valid in the bulk frame of the plasma flow that takes into account convective changes, cooling, velocity diffusion, and charge exchange‐induced injection and loss, the associated moment equation for the evolution of the pressure of the total proton population consisting of thermal solar wind and suprathermal pickup protons is derived. Assuming that the local joint proton distribution can always be represented by a so‐called κ distribution, an ordinary differential equation for the variation of the parameter κ along a given streamline is obtained. This way, the proton velocity distribution can be computed for the whole inner heliosheath. It is demonstrated that the accelerating effect of velocity diffusion is to be expected to overcompensate the loss effect on the proton distribution at higher velocities due to charge exchange with cold interstellar hydrogen atoms. While this corroborates a value of κ < 1.65 in the inner (upwind) heliosheath, at the same time it reveals that the assumption of a constant κ, which was commonly made in earlier studies, should be abandoned.
Satellite‐beacon Ionospheric‐scintillation Global Model of the upper Atmosphere (SIGMA) II: Inverse modeling with high‐latitude observations to deduce irregularity physics
Authors: Deshpande K. B. , Bust G. S. , Clauer C. R. , Scales W. A. , Frissell N. A. , Ruohoniemi J. M. , Spogli L. , Mitchell C. , Weatherwax A. T. 
Published: September 2016

AbstractIonospheric scintillation is caused by irregularities in the ionospheric electron density. The characterization of ionospheric irregularities is important to further our understanding of the underlying physics. Our goal is to characterize the intermediate (0.1–10 km) to medium (10–100 km) scale high‐latitude irregularities which are likely to produce these scintillations. In this paper, we characterize irregularities observed by Global Navigation Satellite System (GNSS) during a geomagnetically active period on 9 March 2012. For this purpose, along with the measurements, we are using the recently developed model: “Satellite‐beacon Ionospheric‐scintillation Global Model of the upper Atmosphere” (SIGMA). The model is particularly applicable at high latitudes as it accounts for the complicated geometry of the magnetic field lines in these regions and is presented in an earlier paper. We use an inverse modeling technique to derive irregularity parameters by comparing the high rate (50 Hz) GNSS observations to the modeled outputs. In this investigation, we consider experimental observations from both the northern and southern high latitudes. The results include predominance of phase scintillations compared to amplitude scintillations that imply the presence of larger‐scale irregularities of sizes above the Fresnel scale at GPS frequencies, and the spectral index ranges from 2.4 to 4.2 and the RMS number density ranges from 3e11 to 2.3e12 el/m3. The best fits we obtained from our inverse method that considers only weak scattering mostly agree with the observations. Finally, we suggest some improvements in order to facilitate the possibility of accomplishing a unique solution to such inverse problems.
Observations of magnetospheric ULF waves in connection with the Kelvin‐Helmholtz instability at Mercury
Authors: Liljeblad E. , Karlsson T. , Sundberg T. , Kullen A. 
Published: September 2016

AbstractThe magnetic field data from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft is investigated to establish the presence of magnetospheric ultralow frequency (ULF) waves in connection with 131 previously observed nonlinear Kelvin‐Helmholtz (KH) waves at Mercury. Distinct ULF wave signatures are detected in 44 out of the 131 magnetospheric traversals prior to or after observing the KH waves. Of these ULF events, 39 out of 44 are highly coherent at the frequency of maximum power spectral density and occur more often on the dayside magnetosphere than away from it. The waves observed at the dayside magnetosphere, which appear mainly at the duskside and naturally following the KH wave occurrence asymmetry, are significantly different from the eveningside or morningside events and have the following distinct wave characteristics: a polarization mainly in the perpendicular (azimuthal) direction to the mean magnetic field, a wave normal angle closer to the parallel than the perpendicular direction, an absolute ellipticity increasing away from noon, almost exclusively a right‐hand polarization, and frequencies in the narrow range of 0.02–0.04 Hz (well below the local Na+ gyrofrequency and in the same range as the KH waves). The results strongly suggest that the large majority of the ULF waves at the dayside observed in this study are driven by KH waves at the magnetopause and that they occur in the vicinity of a field line resonance, which in turn manifests the importance of the Kelvin‐Helmholtz instability in terms of energy and momentum transport throughout Mercury's magnetosphere.
Initializing HYSPLIT with satellite observations of volcanic ash: A case study of the 2008 Kasatochi eruption
Authors: Crawford Alice M. , Stunder Barbara J. B. , Ngan Fong , Pavolonis Michael J. 
Published: September 2016

AbstractThe current work focuses on improving volcanic ash forecasts by integrating satellite observations of ash into the Lagrangian transport and dispersion model, HYSPLIT. The accuracy of HYSPLIT output is dependent on the accuracy of the initialization: the initial position, size distribution, and amount of ash as a function of time. Satellite observations from passive infrared, IR, sensors are used both to construct the initialization term and for verification. Space‐based lidar observations are used for further verification. We compare model output produced using different initializations for the 2008 eruption of Kasatochi in the Aleutian Islands. Simple source terms, such as a uniform vertical line or cylindrical source above the vent, are compared to initializations derived from satellite measurements of position, mass loading, effective radius, and height of the downwind ash cloud. Using satellite measurements of column mass loading of ash to constrain the source term produces better long‐term predictions than using an empirical equation relating mass eruption rate and plume height above the vent. Even though some quantities, such as the cloud thickness, must be estimated, initializations which release particles at the position of the observed ash cloud produce model output which is comparable to or better than the model output produced with source terms located above and around the vent. Space‐based lidar data, passive IR retrievals of ash cloud top height, and model output agree well with each other, and all suggest that the Kasatochi ash cloud evolved into a complex three‐dimensional structure.
Analysis of ground‐based 222Rn measurements over Spain: Filling the gap in southwestern Europe
Authors: Grossi C. , Àgueda A. , Vogel F. R. , Vargas A. , Zimnoch M. , Wach P. , Martín J. E. , López‐Coto I. , Bolívar J. P. , Morguí J. A. , Rodó X. 
Published: September 2016

AbstractHarmonized atmospheric 222Rn observations are required by the scientific community: these data have been lacking in southern Europe. We report on three recently established ground‐based atmospheric 222Rn monitoring stations in Spain. We characterize the variability of atmospheric 222Rn concentrations at each of these stations in relation to source strengths, local, and regional atmospheric processes. For the study, measured atmospheric 222Rn concentrations, estimated 222Rn fluxes, and regional footprint analysis have been used. In addition, the atmospheric radon monitor operating at each station has been compared to a 222Rn progeny monitor. Annual means of 222Rn concentrations at Gredos (GIC3), Delta de l'Ebre (DEC3), and Huelva (UHU) stations were 17.3 ± 2.0 Bq m−3, 5.8 ± 0.8 Bq m−3, and 5.1 ± 0.7 Bq m−3, respectively. The GIC3 station showed high 222Rn concentration differences during the day and by seasons. The coastal station DEC3 presented background concentrations typical of the region, except when inland 222Rn‐rich air masses are transported into the deltaic area. The highest 222Rn concentrations at UHU station were observed when local recirculation facilitates accumulation of 222Rn from nearby source represented by phosphogypsum piles. Results of the comparison performed between monitors revealed that the performance of the direct radon monitor is not affected by meteorological conditions, whereas the 222Rn progeny monitor seems to underestimate 222Rn concentrations under saturated atmospheric conditions. Initial findings indicate that the monitor responses seem to be in agreement for unsaturated atmospheric conditions but a further long‐term comparison study will be needed to confirm this result.
Exhumation history along the eastern Amundsen Sea coast, West Antarctica, revealed by low‐temperature thermochronology
Authors: Lindow Julia , Kamp Peter J. J. , Mukasa Samuel B. , Kleber Michel , Lisker Frank , Gohl Karsten , Kuhn Gerhard , Spiegel Cornelia 
Published: September 2016

AbstractWest Antarctica experienced a complex tectonic history, which is still poorly documented, in part due to extensive ice cover. Here we reconstruct the Cretaceous to present thermotectonic history of Pine Island Bay area and its adjacent coasts, based on a combination of apatite and zircon fission track and apatite (U‐Th‐Sm)/He thermochronology. In addition, we report petrographic information for the catchments of Pine Island, Thurston Island, and Thwaites glaciers. Our data suggest that the underlying bedrock of the Pine Island and Thwaites Glacier catchments are very different and vary from granitoids to (Cenozoic?) volcanogenic sequences and low‐grade metamorphics. Our thermochronology data show that the upper crustal rocks of Pine Island Bay experienced very rapid cooling during the late Cretaceous. We attribute this rapid cooling of basement rocks and associated reduction in mean elevation to tectonic denudation driven by gravitational collapse of the Cretaceous orogen along the proto‐Pacific Gondwana margin. Rapid Cretaceous crustal cooling was followed by very slow cooling during the Cenozoic, with no erosional response—within the limits of thermochronological methods—to the onset of glaciation and subsequent climatic changes. Cenozoic rifting within the West Antarctic Rift appears to have had little effect on erosion processes around Pine Island Bay; instead, our data suggest Cenozoic crustal tilting toward Pine Island Trough, a major geomorphic feature previously suggested to be a branch of the rift system.
A new technique for measuring the bed surface texture during flow and application to a degradational sand‐gravel laboratory experiment
Authors: Orrú Clara , Blom Astrid , Chavarrías Victor , Ferrara Velia , Stecca Guglielmo 
Published: September 2016

AbstractWe present a new image analysis technique for measuring the grain size distribution (texture) of the bed surface during flow in a laboratory experiment. A camera and a floating device are connected to a carriage used to take images of the bed surface over the entire flume length. The image analysis technique, which is based on color segmentation, provides detailed data on spatial and temporal changes of the areal fraction content of each grain size at the bed surface. The technique was applied in a laboratory experiment conducted to examine a degradational reach composed of a well sorted two‐fraction mixture of sand and gravel. The initial bed consisted of an upstream reach that was characterized by an imposed stepwise fining pattern (the bimodal reach) and a downstream sand reach. A lack of sediment supply and partial transport conditions led to the formation of a static armor in the bimodal reach, which resulted in a more abrupt spatial transition in the bed surface mean grain size. The associated spatial transition in slope led to a backwater effect over the bimodal reach, a streamwise reduction in sand mobility, and so a static armor that was governed by a downstream fining pattern. Although a morphodynamic equilibrium state under steady flow is generally characterized by normal flow, here the partial transport regime prevented the bed from adjusting toward normal flow conditions and the morphodynamic steady state was governed by a backwater. We applied a numerical morphodynamic sand‐gravel model to reproduce the laboratory experiment. The numerical model captured the hydrodynamic and morphodynamic adjustment and the static armor well, yet the armoring occurred too slowly. Although the final configuration of the experiment shows features of a gravel‐sand transition (i.e., a sudden transition in slope and mean grain size), we are hesitant to claim similarities between our results and the physical mechanisms governing a gravel‐sand transition in the field.
Unifying catchment water balance models for different time scales through the maximum entropy production principle
Authors: Zhao Jianshi , Wang Dingbao , Yang Hanbo , Sivapalan Murugesu 
Published: September 2016

AbstractThe paper presents a thermodynamic basis for water balance partitioning at the catchment scale, through formulation of flux‐force relationships for the constituent hydrological processes, leading to the derivation of optimality conditions that satisfy the principle of Maximum Entropy Production (MEP). Application of these optimality principles at three different time scales leads to the derivation of water balance equations that mimic widely used, empirical models, i.e., Budyko‐type model over long‐term scale, the “abcd” model at monthly scale, and the SCS model at the event scale. The applicability of MEP in each case helps to draw connections between the water balances at the three different time scales, and to demonstrate a common thermodynamic basis for the otherwise empirical water balance models. In particular, it is concluded that the long time scale Budyko‐type model and the event scale SCS model are both special cases of the monthly “abcd” model.
Analytical solutions of seawater intrusion in sloping confined and unconfined coastal aquifers
Authors: Lu Chunhui , Xin Pei , Kong Jun , Li Ling , Luo Jian 
Published: September 2016

AbstractSloping coastal aquifers in reality are ubiquitous and well documented. Steady state sharp‐interface analytical solutions for describing seawater intrusion in sloping confined and unconfined coastal aquifers are developed based on the Dupuit‐Forchheimer approximation. Specifically, analytical solutions based on the constant‐flux inland boundary condition are derived by solving the discharge equation for the interface zone with the continuity conditions of the head and flux applied at the interface between the freshwater zone and the interface zone. Analytical solutions for the constant‐head inland boundary are then obtained by developing the relationship between the inland freshwater flux and hydraulic head and combining this relationship with the solutions of the constant‐flux inland boundary. It is found that for the constant‐flux inland boundary, the shape of the saltwater interface is independent of the geometry of the bottom confining layer for both aquifer types, despite that the geometry of the bottom confining layer determines the location of the interface tip. This is attributed to that the hydraulic head at the interface is identical to that of the coastal boundary, so the shape of the bed below the interface is irrelevant to the interface position. Moreover, developed analytical solutions with an empirical factor on the density factor are in good agreement with the results of variable‐density flow numerical modeling. Analytical solutions developed in this study provide a powerful tool for assessment of seawater intrusion in sloping coastal aquifers as well as in coastal aquifers with a known freshwater flux but an arbitrary geometry of the bottom confining layer.
Respiratory training in an individual with amyotrophic lateral sclerosis
Authors: Tabor Lauren C. , Rosado Karen M. , Robison Raele , Hegland Karen , Humbert Ianessa A. , Plowman Emily K. 
Published: September 2016

AbstractWe examined the impact of expiratory muscle strength training on maximum expiratory pressure, cough spirometry, and disease progression in a 71‐year‐old male with amyotrophic lateral sclerosis. Maximum expiratory pressure declined 9% over an 8‐week sham training period, but subsequently improved by 102% following 8 weeks of expiratory muscle strength training. Improvements in cough spirometry and mitigated disease progression were also observed post expiratory muscle strength training. Improvements in maximum expiratory pressures were maintained 6 months following expiratory muscle strength training and were 79% higher than baseline data obtained 301 days prior. In this spinal‐onset amyotrophic lateral sclerosis patient, respiratory training improved subglottic air pressure generation and sequential cough generation.
Rapid number naming in chronic concussion: eye movements in the King–Devick test
Authors: Rizzo John‐Ross , Hudson Todd E. , Dai Weiwei , Birkemeier Joel , Pasculli Rosa M. , Selesnick Ivan , Balcer Laura J. , Galetta Steven L. , Rucker Janet C. 
Published: September 2016

AbstractObjectiveThe King–Devick (KD) test, which is based on rapid number naming speed, is a performance measure that adds vision and eye movement assessments to sideline concussion testing. We performed a laboratory‐based study to characterize ocular motor behavior during the KD test in a patient cohort with chronic concussion to identify features associated with prolonged KD reading times.MethodsTwenty‐five patients with a concussion history (mean age: 31) were compared to control participants with no concussion history (n = 42, mean age: 32). Participants performed a computerized KD test under infrared‐based video‐oculography.ResultsAverage intersaccadic intervals for task‐specific saccades were significantly longer among concussed patients compared to controls (324.4 ± 85.6 msec vs. 286.1 ± 49.7 msec, P = 0.027). Digitized KD reading times were prolonged in concussed participants versus controls (53.43 ± 14.04 sec vs. 43.80 ± 8.55 sec, P = 0.004) and were highly correlated with intersaccadic intervals. Concussion was also associated with a greater number of saccades during number reading and larger average deviations of saccade endpoint distances from the centers of the to‐be‐read numbers (1.22 ± 0.29° vs. 0.98 ± 0.27°, P = 0.002). There were no differences in saccade peak velocity, duration, or amplitude.InterpretationProlonged intersaccadic intervals, greater numbers of saccades, and larger deviations of saccade endpoints underlie prolonged KD reading times in chronic concussion. The KD test relies upon a diffuse neurocognitive network that mediates the fine control of efferent visual function. One sequela of chronic concussion may be disruption of this system, which may produce deficits in spatial target selection and planning of eye movements.
Clinical and biophysical characterization of 19 GJB1 mutations
Authors: Tsai Pei‐Chien , Yang De‐Ming , Liao Yi‐Chu , Chiu Tai‐Yu , Kuo Hung‐Chou , Su Yu‐Ping , Guo Yuh‐Cherng , Soong Bing‐Wen , Lin Kon‐Ping , Liu Yo‐Tsen , Lee Yi‐Chung 
Published: September 2016

AbstractObjectiveCharcot–Marie–Tooth disease type X1 (CMTX1), which is caused by mutations in the gap junction (GJ) protein beta‐1 gene (GJB1), is the second most common form of Charcot–Marie–Tooth disease (CMT). GJB1 encodes the GJ beta‐1 protein (GJB1), which forms GJs within the myelin sheaths of peripheral nerves. The process by which GJB1 mutants cause neuropathy has not been fully elucidated. This study evaluated the biophysical characteristics of GJB1 mutants and their correlations with the clinical features of CMTX1 patients.MethodsAll patients with a validated GJB1 mutation were assessed using the Charcot–Marie–Tooth disease neuropathy score version 2 (CMTNS). The impacts of the mutations on the biophysical functions of GJB1 were characterized by assessing intracellular localization, expression patterns, and GJ Ca2+ permeability.ResultNineteen GJB1 mutations were identified in 24 patients with a clinical diagnosis of CMT. Six are novel mutations: p.L6S, p.I20F, p.I101Rfs*8, p.F153L, p.R215P, and p.D278V. Diverse pathological effects of the mutations were demonstrated, including reduced GJB1 expression, intracellular mislocalization, and altered GJ functions. GJB1 mutations that caused a complete loss of GJ Ca2+ permeability appeared to be associated with an earlier disease onset, whereas those resulting in preservation of GJ permeability and with predominant cell membrane expression tended to have a later onset and a milder phenotype.InterpretationThis study demonstrated that the degree of loss of GJ function caused by the GJB1 mutations might contribute to the onset and severity of neuropathic symptoms in CMTX1.