bluuebunny/crossref_metadata_2025_split huggingface dataset:
Flux Enhancements of > 30 keV Electrons at Low Drift Shells L < 1.2 During Last Solar Cycles
Authors: Suvorova A. V. 
Published: December 2017

AbstractWe present results of statistical analysis of enhancements of >30 keV electrons observed by the NOAA/POES satellites during solar cycles 23 and 24 (1998–2016) at low drift shells L < 1.2, so‐called forbidden zone. We collected 1,750 days (~25% of the total time) when fluxes of the forbidden energetic electrons (FEE) exceeded 103 (cm2 s sr)−1. We found 530 days, when FEE fluxes reached high intensity from 104 up to 107 (cm2 s sr)−1. It was found that the FEE enhancements were observed mostly often at the declining phases and solar minimum. More than 85% of the events occurred under fast solar wind (V > 450 km/s), high substorm activity (AL >150 nT), and enhanced interplanetary electric field perturbations (VδB > 1.5 mV/m). The FEE occurrence rate peaks around the local midnight. We have also found a quite unexpected annual variation of the FEE occurrence rate with a pronounced maximum from May to September, a minor peak in December–January, and minima at the equinoxes. The May–September peak, persisting at different solar cycle phases, was assumed to originate from high conductivity in the auroral ionosphere, which is controlled by the dipole tilt angle and provides better conditions for penetration of electric field perturbations into the inner magnetosphere. This allows explanation of the shape and amplitude of annual variation in the FEE occurrence rate from the convolution of the solar wind driver with the penetration conditions.
Super‐Alfvénic Propagation and Damping of Reconnection Onset Signatures
Authors: Sharma Pyakurel P. , Shay M. A. , Haggerty C. C. , Parashar T. N. , Drake J. F. , Cassak P. A. , Gary S. Peter 
Published: December 2017

AbstractThe quadrupolar out‐of‐plane Hall magnetic field generated during collisionless reconnection propagates away from the x line as a kinetic Alfvén wave (KAW). While it has been shown that this KAW carries substantial Poynting flux and propagates super‐Alfvenically, how this KAW damps as it propagates away from the x line is not well understood. In this study, this damping is examined using kinetic particle‐in‐cell simulations of antiparallel symmetric magnetic reconnection in a one‐dimensional current sheet equilibrium. In the reconnection simulations, the KAW wave vector has a typical magnitude comparable to an inverse fluid Larmor radius (effectively an inverse ion Larmor radius) and a direction of 85–89° relative to the local magnetic field. We find that the damping of the reconnection KAW is consistent with linear Landau damping results from a numerical Vlasov dispersion solver. This knowledge allows us to generalize our damping predictions to regions in the magnetotail and solar corona where the magnetic geometry can be approximated as a current sheet. For the magnetotail, the KAW from reconnection will not damp away before propagating the approximately 20 Earth radii associated with global magnetotail distances. For the solar corona, on the other hand, these KAWs will completely damp before reaching the distances comparable to the flare loop length.
Global Distribution and Variations of NO Infrared Radiative Flux and Its Responses to Solar Activity and Geomagnetic Activity in the Thermosphere
Authors: Tang Chaoli , Wei Yuanyuan , Liu Dong , Luo Tao , Dai Congming , Wei Heli 
Published: December 2017

AbstractThe global distribution and variations of NO infrared radiative flux (NO‐IRF) are presented during 2002–2016 in the thermosphere covering 100–280 km altitude based on Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) data set. For investigating the spatial variations of the mutual relationship between NO‐IRF and solar activity, the altitude ranges from 100 km to 280 km are divided into 90 altitude bins, and the latitude regions of 83°S–83°N are divided into 16 latitude bins. By processing about 1.8E9 NO‐IRF observation values from about 5E6 vertical nighttime profiles recorded in SABER data set, we obtained more than 4.1E8 samples of NO‐IRF. The annual‐mean values of NO‐IRF are then calculated by all available NO‐IRF samples within each latitude and altitude bin. Local latitudinal maxima in NO‐IRF are found between 120 and 145 km altitude, and the maximum NO‐IRF located at polar regions are 3 times more than that of the minimum at equatorial region. The influences of solar and geomagnetic activity on the spatial variations of NO‐IRF are investigated. Both the NO‐IRF and its response to solar and geomagnetic activity show nearly symmetric distribution between the two hemispheres. It is demonstrated that the observed changes in NO‐IRF at altitudes between 100 and 225 km correlate well with the changes in solar activity. The NO‐IRF at solar maximum is about 4 times than that at solar minimum, and the current maximum of NO‐IRF in 2014 is less than 70% of the prior maximum in 2001. For the first time, the response ranges of the NO‐IRF to solar and geomagnetic activity at different altitudes and latitudes are reported.
GPS‐TEC Observation of Gravity Waves Generated in the Ionosphere During 21 August 2017 Total Solar Eclipse
Authors: Nayak Chinmaya , Yiğit Erdal 
Published: December 2017

AbstractThe present work investigates ionospheric effects of the 21 August 2017 total solar eclipse, particularly targeting eclipse‐generated gravity waves in the ionosphere. Ionospheric total electron content (TEC) derived from Global Positioning System (GPS) data obtained from a number of stations located both along and across the path of eclipse totality has been utilized for this purpose. Distinct gravity wave‐like signatures with wave periods around 20–90 min (with dominant peak at 25–30 min wave period) have been observed at all locations both in the path of totality and away from it. The observed gravity waves are more intense at locations closer to the path of totality, and the wave amplitudes decrease gradually with increasing distance from the path of totality. Our result highlights the manifestation of eclipse‐generated waves in the variability of the terrestrial ionosphere.
Variability of the Space‐Time Evolution of Slow Slip Events Off the Boso Peninsula, Central Japan, From 1996 to 2014
Authors: Fukuda Jun'ichi 
Published: December 2017

AbstractGlobal Navigation Satellite System data are inverted to investigate the space‐time evolution of five Mw 6.6–6.7 slow slip events (SSEs) off the Boso Peninsula, central Japan, in 1996, 2002, 2007, 2011, and 2013–2014. Our analyses reveal that the nucleation style and space‐time evolution of slip vary among the five SSEs. The 2002, 2007, and 2011 SSEs nucleated more rapidly, with moment accelerations higher than those of the 1996 SSE by a factor of ∼2–6, and higher than those of the 2013–2014 SSE by an order of magnitude. Furthermore, the 2002, 2007, and 2011 SSEs exhibited more rapid temporal variations in their slip and moment rates and showed larger seismic moments and higher maximum slip rates than the 1996 and 2013–2014 SSEs, suggesting that the overall evolution of the SSEs is correlated with the nucleation style. The along‐strike expansion/propagation of slip is identified for the five SSEs, revealing that the expansion/propagation patterns vary from event to event. The earthquake swarms accompanying the SSEs occurred near the downdip edge of high‐slip‐rate areas, and the seismicity migrated during slow slip with directions and speeds similar to those of the slip expansion/propagation. These space‐time correlations between seismicity and slow slip suggest that the earthquake swarms were triggered by stress changes due to slow slip. The relative timing between the onsets of the SSEs and their associated seismicity varies from event to event and appears to be correlated with the nucleation style of the SSEs.
On the Grain Size Sensitivity of Olivine Rheology
Authors: Jain Chhavi , Korenaga Jun , Karato Shun‐ichiro 
Published: December 2017

AbstractUsing the Markov chain Monte Carlo (MCMC) inversion technique of Mullet et al. (2015), we reassess the validity of the conventionally accepted values of the grain size exponent of diffusion creep in olivine aggregates. A systematic and comprehensive analysis of individual experimental runs taken from three widely cited studies reveals that these data do not tightly constrain the grain size exponent or any other flow law parameter for diffusion and dislocation creep. Our analysis indicates that large data uncertainties can cause inversion results to deviate significantly from true values because of the covariance between the grain size and stress exponents, and that even resolving a grain size exponent of 2 from 3 is difficult. The versatility of our MCMC inversion technique can, however, be exploited to improve this situation by identifying optimal conditions for future experimental studies. Because the uncertainties of the grain size and stress exponents are highly correlated, for example, increasing the range of grain size variation can help better constrain both exponents simultaneously.
The Role of Coseismic Coulomb Stress Changes in Shaping the Hard Link Between Normal Fault Segments
Authors: Hodge M. , Fagereng Å , Biggs J. 
Published: December 2017

AbstractThe mechanism and evolution of fault linkage is important in the growth and development of large faults. Here we investigate the role of coseismic stress changes in shaping the hard links between parallel normal fault segments (or faults), by comparing numerical models of the Coulomb stress change from simulated earthquakes on two en echelon fault segments to natural observations of hard‐linked fault geometry. We consider three simplified linking fault geometries: (1) fault bend, (2) breached relay ramp, and (3) strike‐slip transform fault. We consider scenarios where either one or both segments rupture and vary the distance between segment tips. Fault bends and breached relay ramps are favored where segments underlap or when the strike‐perpendicular distance between overlapping segments is less than 20% of their total length, matching all 14 documented examples. Transform fault linkage geometries are preferred when overlapping segments are laterally offset at larger distances. Few transform faults exist in continental extensional settings, and our model suggests that propagating faults or fault segments may first link through fault bends or breached ramps before reaching sufficient overlap for a transform fault to develop. Our results suggest that Coulomb stresses arising from multisegment ruptures or repeated earthquakes are consistent with natural observations of the geometry of hard links between parallel normal fault segments.
Assessment of NPP VIIRS Albedo Over Heterogeneous Crop Land in Northern China
Authors: Wu Xiaodan , Wen Jianguang , Xiao Qing , Yu Yunyue , You Dongqin , Hueni Andreas 
Published: December 2017

AbstractIn this paper, the accuracy of Suomi National Polar‐orbiting Partnership Visible Infrared Imaging Radiometer Suite (VIIRS) land surface albedo, which is derived from the direct estimation algorithm, was assessed using ground‐based albedo observations from a wireless sensor network over a heterogeneous cropland in the Huailai station, northern China. Data from six nodes spanning 2013–2014 over vegetation, bare soil, and mixed terrain surfaces were utilized to provide ground reference at VIIRS pixel scale. The performance of VIIRS albedo was also compared with Global LAnd Surface Satellite (GLASS) and Moderate Resolution Imaging Spectroradiometer (MODIS) albedos (Collection 5 and 6). The results indicate that the current granular VIIRS albedo has a high accuracy with a root‐mean‐square error of 0.02 for typical land covers. They are significantly correlated with ground references indicated by a correlation coefficient (R) of 0.73. The VIIRS albedo shows distinct advantages to GLASS and MODIS albedos over bare soil and mixed‐cover surfaces, while it is inferior to the other two products over vegetated surfaces. Furthermore, its time continuity and the ability to capture the abrupt change of surface albedo are better than that of GLASS and MODIS albedo.
Soil Moisture Controls the Thermal Habitat of Active Layer Soils in the McMurdo Dry Valleys, Antarctica
Authors: Wlostowski A. N. , Gooseff M. N. , Adams B. J. 
Published: December 2017

AbstractAntarctic soil ecosystems are strongly controlled by abiotic habitat variables. Regional climate change in the McMurdo Dry Valleys is expected to cause warming over the next century, leading to an increase in frequency of freeze‐thaw cycling in the soil habitat. Previous studies show that physiological stress associated with freeze‐thaw cycling adversely affects invertebrate populations by decreasing abundance and positively selecting for larger body sizes. However, it remains unclear whether or not climate warming will indeed enhance the frequency of annual freeze‐thaw cycling and associated physiological stresses. This research quantifies the frequency, rate, and spatial heterogeneity of active layer freezing to better understand how regional climate change may affect active layer soil thermodynamics, and, in turn, affect soil macroinvertebrate communities. Shallow active layer temperature, specific conductance, and soil moisture were observed along natural wetness gradients. Field observations show that the frequency and rate of freeze events are nonlinearly related to freezable soil moisture (θf). Over a 2 year period, soils at θf < 0.080 m3/m3 experienced between 15 and 35 freeze events and froze rapidly compared to soils with θf > 0.080 m3/m3, which experienced between 2 and 6 freeze events and froze more gradually. A numerical soil thermodynamic model is able to simulate observed freezing rates across a range of θf, reinforcing a well‐known causal relationship between soil moisture and active layer freezing dynamics. Findings show that slight increases in soil moisture can potentially offset the effect of climate warming on exacerbating soil freeze‐thaw cycling.
Cost‐Loss Analysis of Ensemble Solar Wind Forecasting: Space Weather Use of Terrestrial Weather Tools
Authors: Henley E. M. , Pope E. C. D. 
Published: December 2017

AbstractThis commentary concerns recent work on solar wind forecasting by Owens and Riley (2017, https://doi.org/10.1002/2017SW001679). The approach taken makes effective use of tools commonly used in terrestrial weather—notably, via use of a simple model—generation of an “ensemble” forecast, and application of a “cost‐loss” analysis to the resulting probabilistic information, to explore the benefit of this forecast to users with different risk appetites. This commentary aims to highlight these useful techniques to the wider space weather audience and to briefly discuss the general context of application of terrestrial weather approaches to space weather.
Real‐Time Optimal Flood Control Decision Making and Risk Propagation Under Multiple Uncertainties
Authors: Zhu Feilin , Zhong Ping‐An , Sun Yimeng , Yeh William W.‐G. 
Published: December 2017

AbstractMultiple uncertainties exist in the optimal flood control decision‐making process, presenting risks involving flood control decisions. This paper defines the main steps in optimal flood control decision making that constitute the Forecast‐Optimization‐Decision Making (FODM) chain. We propose a framework for supporting optimal flood control decision making under multiple uncertainties and evaluate risk propagation along the FODM chain from a holistic perspective. To deal with uncertainties, we employ stochastic models at each link of the FODM chain. We generate synthetic ensemble flood forecasts via the martingale model of forecast evolution. We then establish a multiobjective stochastic programming with recourse model for optimal flood control operation. The Pareto front under uncertainty is derived via the constraint method coupled with a two‐step process. We propose a novel SMAA‐TOPSIS model for stochastic multicriteria decision making. Then we propose the risk assessment model, the risk of decision‐making errors and rank uncertainty degree to quantify the risk propagation process along the FODM chain. We conduct numerical experiments to investigate the effects of flood forecast uncertainty on optimal flood control decision making and risk propagation. We apply the proposed methodology to a flood control system in the Daduhe River basin in China. The results indicate that the proposed method can provide valuable risk information in each link of the FODM chain and enable risk‐informed decisions with higher reliability.
A comparison of two pencil beam scanning treatment planning systems for proton therapy
Authors: Langner Ulrich W. , Mundis Michelle , Strauss Dan , Zhu Mingyao , Mossahebi Sina 
Published: December 2017

AbstractObjectiveAnalytical dose calculation algorithms for Eclipse and Raystation treatment planning systems (TPS), as well as a Raystation Monte Carlo model are compared to corresponding measured point doses.MethodThe TPS were modeled with the same beam data acquired during commissioning. Thirty‐five typical plans were made with each planning system, 31 without range shifter and four with a 5 cm range shifter. Point doses in these planes were compared to measured doses.ResultsThe mean percentage difference for all plans between Raystation and Eclipse were 1.51 ± 1.99%. The mean percentage difference for all plans between TPS models and measured values are −2.06 ± 1.48% for Raystation pencil beam (PB), −0.59 ± 1.71% for Eclipse and −1.69 ± 1.11% for Raystation monte carlo (MC). The distribution for the patient plans were similar for Eclipse and Raystation MC with a P‐value of 0.59 for a two tailed unpaired t‐test and significantly different from the Raystation PB model with P = 0.0013 between Raystation MC and PB. All three models faired markedly better if plans with a 5 cm range shifter were ignored. Plan comparisons with a 5 cm range shifter give differences between Raystation and Eclipse of 3.77 ± 1.82%. The mean percentage difference for 5 cm range shifter plans between TPS models and measured values are −3.89 ± 2.79% for Raystation PB, −0.25 ± 3.85% for Eclipse and 1.55 ± 1.95% for Raystation MC.ConclusionBoth Eclipse and Raystation PB TPS are not always accurate within ±3% for a 5 cm range shifters or for small targets. This was improved with the Raystation MC model. The point dose calculations of Eclipse, Raystation PB, and Raystation MC compare within ±3% to measured doses for the other scenarios tested.
MRI biomarkers of proximal nerve injury in CIDP
Authors: Lichtenstein Thorsten , Sprenger Alina , Weiss Kilian , Slebocki Karin , Cervantes Barbara , Karampinos Dimitrios , Maintz David , Fink Gereon R. , Henning Tobias D. , Lehmann Helmar C. 
Published: December 2017

AbstractObjectiveTo evaluate the utility of nerve diffusion tensor imaging (DTI), nerve cross‐sectional area, and muscle magnetic resonance imaging (MRI) multiecho Dixon for assessing proximal nerve injury in chronic inflammatory demyelinating polyneuropathy (CIDP).MethodsIn this prospective observational cohort study, 11 patients with CIDP and 11 healthy controls underwent a multiparametric MRI protocol with DTI of the sciatic nerve and assessment of muscle proton‐density fat fraction of the biceps femoris and the quadriceps femoris muscles by multiecho Dixon MRI. Patients were longitudinally evaluated by MRI, clinical examination, and nerve conduction studies at baseline and after 6 months.ResultsIn sciatic nerves of CIDP patients, mean cross‐sectional area was significantly higher and fractional anisotropy value was significantly lower, compared to controls. In contrast, muscle proton‐density fat fraction was significantly higher in thigh muscles of patients with CIDP, compared to controls. MRI parameters showed high reproducibility at baseline and 6 months.InterpretationAdvanced MRI parameters demonstrate subclinical proximal nerve damage and intramuscular fat accumulation in CIDP. Data suggest DTI and multiecho Dixon MRI might be useful in estimating axonal damage and neurogenic muscle changes in CIDP.
Mesoporous Caged‐γ‐AlOOH‐Double‐Stranded RNA Analog Complexes for Cancer Immunotherapy
Authors: Li Xia , Shenashen Mohamed A. , Wang Xiupeng , Ito Atsuo , Taniguchi Akiyoshi , EI‐Safty Sherif A. 
Published: December 2017

AbstractAlum exhibits the superior biocompatibility in the history of human healthcare, as the only FDA‐approved inorganic adjuvant in most human vaccines. However, up to now, there are few reports about the in‐depth research between its nanostructure and carrier properties in vitro and in vivo. In this study, the caged architecture of uniform mesoporous γ‐AlOOH nanorods (MANRs) comprises realigned pores and open windows at the edges, 1D tubular tunnels, and oxyhydroxide layer that can serve as carriers for cancer immunotherapy. Compared with commercial alum, the MANRs exhibit a higher loading amount of a model cancer antigen and a stronger intracellular uptake by THP‐1‐differentiated macrophage‐like cells in vitro. Compared with commercial alum and soluble ovalbumin, the MANRs loaded with a model cancer antigen, ovalbumi, and an immunopotentiator, double‐stranded RNA analog poly(I:C) markedly increase the anticancer immunity and CD4+ and CD8+ T cell populations in mouse splenocytes in vivo. The MANRs are promising as an adjuvant substance in cancer immunotherapy for clinical use.
Potassium‐Ion Battery Anode Materials Operating through the Alloying–Dealloying Reaction Mechanism
Authors: Sultana Irin , Rahman Md Mokhlesur , Chen Ying , Glushenkov Alexey M. 
Published: December 2017

AbstractAnode materials that operate via the alloying–dealloying reaction mechanism are well known in established and maturing battery systems such as lithium‐ion and sodium‐ion batteries. Recently, a new type of metal‐ion battery that utilizes K+ ions in its operating principle has attracted significant attention due to a possibility of building high voltage cells using an abundant potassium ionic shuttle. Establishing promising electrode materials is of paramount importance for this new type of battery. This feature article summarizes available early results on the alloying–dealloying anode materials in potassium electrochemical cells. Based on original research (some data are presented for the first time) and independently published literature, experimental results on silicon, tin, phosphorus, antimony, and lead‐containing anodes are critically discussed. The electrochemical properties, charge storage mechanisms, and achievable capacities are considered. The results are compared with the behaviors of the same materials in lithium and sodium cells, and the importance of the volumetric parameters of electrodes is emphasized. Finally, a number of further research directions in these interesting anode materials are suggested. The feature article provides a useful reference for the growing number of researchers and specialists working in the field of emerging metal‐ion batteries with non‐lithium chemistries.