bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical Variations in the 1998, 2011, and 2015 Lava Flows From Axial Seamount, Juan de Fuca Ridge: Cooling During Ascent, Lateral Transport, and Flow
Authors: Clague David A. , Paduan Jennifer B. , Dreyer Brian M. , Chadwick William W. , Rubin Kenneth R. , Perfit Michael R. , Fundis Allison T. 
Published: August 2018

AbstractLava flows erupted at Axial Seamount in 1998, 2011, and 2015 are chemically heterogeneous and display decreases in MgO content in their glass rinds with increasing distance from the summit. The trends are consistent with eruption temperature decreases down the rift zones of ~0.5 °C/km within 20 km of the caldera and ~0.9 °C/km at greater distance (only observed in the 2011 eruption). Cooling during magma transport in dikes is the likely cause of the temperature trends observed, related to the effects of cooler wall rocks in areas with less frequent dike intrusions. Flows also cooled as they advanced on the seafloor at rates 3–5 times greater than observed at Kilauea volcano in Hawaii for subaerial tube‐fed pahoehoe flows. Lavas erupted in and near the caldera in 1998 and 2011 are slightly enriched transitional mid‐ocean ridge basalt that are aphyric and have glass MgO content of 7.1–7.6 wt %. The 2015 lavas have similarly enriched incompatible element compositions typical of transitional mid‐ocean ridge basalt, but those erupted inside and on the northeast rim of the caldera contain higher glass MgO of 7.8–8.3 wt % and more abundant plagioclase phenocrysts typical of the normal mid‐ocean ridge basaltic lavas erupted between 1290 and 1370 CE. The brief recharge period between the 2011 and 2015 eruptions did not allow magma stored in the shallow reservoir to cool and degas as much as between prior eruptions since 1650 CE, suggesting that the most recent recharge period was shorter than the multicentennial average.
Using Isotopic and Geochemical Tracers to Determine the Contribution of Glacier‐Snow Meltwater to Streamflow in a Partly Glacierized Alpine‐Gorge Catchment in Northeastern Qinghai‐Tibet Plateau
Authors: Chang Qixin , Ma Rui , Sun Ziyong , Zhou Aiguo , Hu Yalu , Liu Yanguang 
Published: August 2018

AbstractCompared with arctic and subarctic catchments, our knowledge about the hydrological functions of glaciers and porous aquifers is still limited for the partly glacierized alpine‐gorge headwaters in the Qinghai‐Tibet Plateau. Here we examine the impact of glacial and groundwater storage on the variability of warm‐season (June to September) discharge from the Hulugou catchment, an alpine‐gorge headwater with 3% glacial coverage, by quantifying the timing and magnitude of contributions of glacier‐snow meltwater, baseflow, and rainwater to streamflow using a three‐component hydrograph separation model. It is found that baseflow was the largest component (55 ± 2%) of warm‐season streamflow while glacier‐snow meltwater also contributed significantly (30 ± 10%) despite of the very low glacial coverage. We suggest that the water flowing out of glaciers was mainly supplied by the melting short‐ and intermediate‐term storages (i.e., snow over glaciers), which led to the high meltwater contribution to streams during the warm season and the high peaks of meltwater discharge following heavy precipitation events. The porous aquifers in piedmont plain may serve as major reservoirs that store a growing body of groundwater during the warm season, which explains the general increasing trend of baseflow contribution during this period. The moraine and talus deposits in high mountains, by contrast, allow groundwater to pass through them quickly and therefore being responsible for the obvious responses of baseflow contribution amount to heavy rainfall events. Our findings suggest that small mountain glaciers and porous aquifers may play a greater role than expected in hydrological regulation in the alpine‐gorge catchments of northeastern Qinghai‐Tibet Plateau.
Improving Short‐Term Rainfall Forecasts by Assimilating Weather Radar Reflectivity Using Additive Ensemble Perturbations
Authors: Yokota S. , Seko H. , Kunii M. , Yamauchi H. , Sato E. 
Published: August 2018

AbstractTo improve short‐term rainfall forecasts through direct assimilation of radar reflectivity, atmospheric variables associated with rainfall should be modified based on their correlation with reflectivity. However, it is difficult to estimate such correlations. The ensemble Kalman filter can estimate the correlation by means of ensemble forecasts, although the estimation is limited to when rainfall is forecast by at least one member at analysis points. To assimilate reflectivity effectively even at points at which no rainfall is forecast, we suggest adding ensemble reflectivity perturbations, which are correlated with atmospheric variables, before ensemble Kalman filter assimilation. In the present study, this correlation is calculated in the whole computational domain including the rainfall regions. We apply this procedure to assimilation experiments with 1‐km horizontal grid interval for two tornadic supercells that occurred on 6 May 2012 and on 2 September 2013, and we succeed in improving short‐term rainfall forecasts by modifying wind, temperature, and water vapor.
Validation of SABER v2.0 Operational Temperature Data With Ground‐Based Lidars in the Mesosphere‐Lower Thermosphere Region (75–105 km)
Authors: Dawkins E. C. M. , Feofilov A. , Rezac L. , Kutepov A. A. , Janches D. , Höffner J. , Chu X. , Lu X. , Mlynczak M. G. , Russell J. 
Published: August 2018

AbstractThe National Aeronautics and Space Administration (NASA) Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) Sounding of the Atmosphere using Broadband Radiometry (SABER) instrument performs near‐global measurements of the vertical kinetic temperature (Tk) profiles and volume mixing ratios of various trace species (including O3, CO2, and H2O), with data available from 2002 to present. In this work, the first comparative study of the latest publically available SABER version 2.0 operational retrieval is reported in order to assess the performance of satellite Tk profiles relative to high‐resolution ground‐based lidar profiles. Collocated multiyear seasonal average Tk profiles were compared at nine different locations, representing a variety of different latitudes. In general, the SABER v2.0 and lidar mean seasonal Tk profiles agree well, with the smallest absolute values of ΔTk (z) (SABER minus lidar) found between 85 and 95 km, where the respective SABER and lidar uncertainties were smallest. At altitudes ≥100 km, the SABER Tk (z) typically exhibited warmer temperatures relative to the lidar Tk (z) profiles, whereas for altitudes ≤85 km, SABER Tk (z) was cooler. Relative to lidar, SABER tends to exhibit a warm bias during high‐latitude summertime, with the reasons for this currently still unclear. Overall, SABER was able to reproduce the general latitude‐ and season‐specific variations in the lidar Tk profiles and shown to be statistically similar for most seasons, at most locations, for the majority of altitudes, and with no overall bias.
On the Upward Extension of the Polar Vortices Into the Mesosphere
Authors: Harvey V. Lynn , Randall Cora E. , Goncharenko Larisa , Becker Erich , France Jeff 
Published: August 2018

AbstractThe polar vortices play a central role in vertically coupling the atmosphere from the ground to geospace by shaping the background wind field through which atmospheric waves propagate. This work extends the vertical range of previous polar vortex climatologies into the upper mesosphere. The mesospheric polar vortices are defined using the CO gradient method with Microwave Limb Sounder satellite data; the stratospheric polar vortices are defined using a stream function‐based algorithm with data from meteorological reanalyses. Strengths and weaknesses of the two vortex definitions are given, as well as recommendations for when, where, and why to use each definition. Midwinter mean vortex geometry in the mesosphere is funnel shaped in the Arctic, with a wide top and narrow bottom. The Antarctic mesospheric vortex tapers with height in early winter and broadens with height in late winter. The seasonal evolution of mesospheric vortex frequency of occurrence, size, and zonal symmetry in both hemispheres is presented. Unexpected behavior above 60 km includes late season vortex broadening in both hemispheres, especially following winters without sudden stratospheric warmings. Following extreme stratospheric disturbances the polar night jet in the mesosphere strengthens and shifts poleward, resulting in a mesospheric vortex that contracts. Overall, the mesospheric polar vortices are more similar between the two hemispheres than their stratospheric counterparts. The vortex climatology presented here serves as an observational benchmark to which the mesospheric polar vortices in high‐top climate models can be evaluated.
Radiation Effects on Satellites During Extreme Space Weather Events
Authors: Hands A. D. P. , Ryden K. A. , Meredith N. P. , Glauert S. A. , Horne R. B. 
Published: August 2018

AbstractHigh‐energy trapped electrons in the Van Allen belts pose a threat to the survivability of orbiting spacecraft. Two key radiation effects are total ionizing dose and displacement damage dose in components and materials, both of which cause cumulative and largely irreversible damage. During an extreme space weather event, trapped electron fluxes in the Van Allen belts can increase by several orders of magnitude in intensity, leading to an enhanced risk of satellite failure. We use extreme environments generated by modeling and statistical analyses to estimate the consequences for satellites in terms of the radiation effects described above. A worst‐case event could lead to significant losses in power generating capability—up to almost 8%—and cause up to four years' worth of ionizing dose degradation, leading to component damage and a life‐shortening effect on satellites. The consequences of such losses are hugely significant given our increasing reliance on satellites for a vast array of services, including communication, navigation, defense, and critical infrastructure.
Fluid Flow, Brecciation, and Shear Heating on Faults: Insights From Carbonate Clumped‐Isotope Thermometry
Authors: Swanson E. M. , Wernicke B. P. , Eiler J. M. 
Published: August 2018

AbstractSlip on gently dipping detachments in the brittle crust has been enigmatic for decades, because fracture mechanics laws predict frictional resistance is too great for sliding to occur, except under rather unusual circumstances. The Miocene Mormon Peak detachment in Nevada and the Eocene Heart Mountain detachment in Wyoming are two well‐studied examples of upper crustal, carbonate‐hosted low‐angle detachments, with highly debated slip processes. Both low‐angle faults were active during regional magmatism, and a number of proposed slip mechanisms involve magmatic fluids, frictional heating, or both. To address the role that magmatic fluids and frictional heating may have played in reducing friction, we measured clumped‐isotope ratios on 137 carbonate samples from these faults. The majority of fault breccias and gouges on the detachment slip surface record temperatures that are colder than the host rock. Surprisingly, samples from within 5 m of the Heart Mountain detachment average just 65 °C, and not a single sample (out of 37 measurements, excluding metamorphosed host rock at White Mountain) records a temperature greater than 90 °C. Along both faults, most samples are depleted in δ18O relative to the host rock, indicating that meteoric, not magmatic, fluids were present and interacting with the fault rock. However, a few samples preserve temperatures of over 160 °C, which, based on textural and geochemical criteria, are difficult to explain other than by frictional heating during slip. These temperatures are recorded in one sample directly on the Mormon Peak detachment slip surface and in two hanging wall localities above the Heart Mountain detachment.
Synchronous Seafloor Spreading and Subduction at the Paleo‐Convergent Margin of Semail and Arabia
Authors: Boudier Françoise , Nicolas Adolphe 
Published: August 2018

AbstractThe Semail ophiolite is the largest and best‐exposed ophiolite, having preserved intact record of a precollision system related to Neotethyan Ocean closure. Breaking with the alternative models of ophiolite exhumation and emplacement, this paper builds on integrating the joined contribution of tectonic evolution of the continental margin in the premise of the ophiolite obduction. Connecting the along‐strike segmentation of the ophiolite recorded in the lithospheric flow structure, and recent high‐precision dating, results in a 3‐D model of evolution of the ophiolite and its continental margin during Jurassic‐Cretaceous time. Among the relevant characteristics newly accounted, (1) the contamination of the ophiolite by fluids and magmas of continental origin; (2) the discrimination of different types of metamorphics associated to the ophiolite, and conventionally classified metamorphic soles; (3) the instability of the Arabian margin during the Late Jurassic‐Cretaceous times; (4) the new precise ages relating to overlapping of spreading and detachment; and (5) the inferred vergence of Neotethyan closure during late Mesozoic are stressed. The complex stem revealed may relate to processes associated with spreading center subduction at ridge‐trench‐transform (RTT) triple junction, as documented along a convergent margin. The Semail ophiolite emplacement on the Arabia continental margin would result from a temporary Arabian platform‐directed subduction zone that consumed the southern Tethyan plate during Late Jurassic‐Cretaceous time.
Kinematics analysis and experiment of a lily picking mechanical arm
Authors: Jiang Ao , Yao Xiang , Cheng Ming , Zhou Juan 
Published: August 2018

A lily flower is a medicinal plant, which has been widely used in the Chinese medicine industry in recent years. According to the rapid picking of the lily flower, a scheme of the mechanical arm picking structure was designed, and the system with an end effector, manipulator and control system was used. The mechanical arm adopts a three‐stage connecting rod structure. Through the lily plant growth of more than about 85% <50 cm characteristics of the mechanical arm were picked up from the top to bottom operation strategy. Based on this, the kinematics model of the picking robotic manipulator is designed. The kinematic equation of the manipulator is demonstrated by a DH deducing method. The kinematics simulation of the manipulator is carried out by MATLAB. The mechanical arm kinematics and picking experiments were carried out in the experimental field in a natural environment by the robotic physical machine platform. The results showed that the manipulator position error from the end of the arm was <12 mm and the picking success rate was 83.33%.
Influence of the hybrid‐driven method on the electromagnetic properties of an electromagnetic motor
Authors: Zhao Jing‐Bo , Liu Hai‐Mei , Bei Shao‐Yi 
Published: August 2018

In the light of an electromagnetic motor driving system, electromagnetic conversion characteristics and structural principles were described. Electromagnetic drive and hybrid‐driven method were proposed; the mathematical models describing the two drive systems which have adopted the magnetic circuit analysis method were established, starting with a discussion on how the drive system affects the electromagnetic force and air‐gap magnetic flux density. Under the same conditions, the electromagnetic drive and hybrid‐driven model were, respectively, simulated to reveal the impact on the electromagnetic force and air‐gap magnetic flux density due to the different driving modes. Variation of the electromagnetic force with an increasing coil current of two types of drive systems under motor speed control is studied preliminarily. The results have shown that compared to that of the pure electromagnetic drive system, the electromagnetic force of the hybrid drive system was raised from 2198 to 4097 N, and the air‐gap magnetic flux density was increased from 1.048 to 1.393 T; the electromagnetic characteristics of the magnetically driven motor were improved effectively.
Indoor positioning technology based on map information perception
Authors: Gan Xingli , Huang Lu , Wang Boyuan , Li Shuang 
Published: August 2018

With the increasing demand for location‐based services, indoor positioning technology has become one of the most attractive areas of research. Microelectromechanical systems sensors in smart terminals are used to realise a pedestrian dead reckoning algorithm. Owing to the accumulated error increased with time, the results of positioning will produce a large error, and an indoor positioning method based on the perception and constraint of map information is designed including straight path constraint and inflection point constraint. In the method of inflection point constraint, several common machine learning algorithms are compared through the experiments, and the secondary discriminant method is utilised to detect the inflection point with a detection accuracy of 97.62%. Finally, the performances of the improved algorithm and the traditional dead reckoning algorithm are compared in the experiments. The results show that the average positioning accuracy of the improved algorithm is 0.073 m, the positioning accuracy within 1 m reaches 100%, it is obviously higher than that of the traditional positioning algorithm and the effectiveness of the algorithm is verified.
Solution of the inverse problem of magnetic induction tomography based on Helmholtz coil
Authors: Luo Hai‐Jun , Wen Kai‐Xu , Yong Liao , Pan Haitao , Jing Xin 
Published: August 2018

Magnetic induction tomography is a contactless technique that can measure conductivity distribution in biological tissues. This study proposed that Helmholtz coils as the excitation coils will generate a set of uniform excitation fields. The system model consists of a circular background area, a circular disturbance object, a set of Helmholtz coils, and eight magnetic detection coils. The diameter of the Helmholtz coil is 200 mm. The detection coil is a square, and its side length is 12 mm. The excitation current of the system is 30 mA, and the frequency is 10 MHz. This study discusses the reconstructed images of different locations, different volumes, different distances, and different electrical conductivities of perturbation bodies. The anti‐noise ability of different noise signals is also analysed. Finally, the image differences are evaluated through structural similarity index (SSIM). The results show that the algorithm can distinguish the position and volume characteristics of the target object. However, when the volume of the target object is low, the position will be deviated. This algorithm can distinguish the position of the two, which is far away from each other.
Invert‐U‐Net DNN segmentation model for MRI cardiac left ventricle segmentation
Authors: Cong Chao , Zhang Hongmin 
Published: August 2018

In this study, a deeply supervised end‐to‐end model is presented for fully automated segmentation for cardiac magnetic resonance imaging (MRI) images. Firstly, the mechanism of deep neural network (DNN)‐based segmentation is discussed with the relationship of channels and their distribution in network in depth. Following this idea, a U‐Net‐based model, namely an invert‐U‐Net model is presented with an innovative filter number structure. Based on the invert‐U‐Net model, the experiment is carefully designed, and the hyper‐parameters are considerately arranged. Finally, the model is applied and evaluated using Sunnybrook MR datasets from the MICCAI 2009 LV segmentation challenge and the experimental result shows that it outperforms the state‐of‐the‐art methods.
Morphology control and optical properties of Bi2O3 crystals prepared by low‐temperature liquid phase method
Authors: Li Jin , Wu Ben Ze , Zhou Zhen Xiang 
Published: August 2018

γ‐Bi2O3 powders were prepared from [Bi(NO3)3 ·5H2 O] and NaOH through low‐temperature liquid phase method at <90°C. This process featured low cost, simplicity and a normal pressure. Bismuth oxides were synthesised in large quantities in water systems. Morphology, structure and optical properties were characterised by X‐ray diffraction, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and ultraviolet visible absorption spectrophotometry (UV–Vis). The SEM indicated that tetrahedral Bi2O3 with the edge length of 1–5 μm was formed. The FTIR spectra show a chemical bond of Bi–O existed. Bi2O3 presents the photo absorption properties from UV light region to visible light and the band gap of the Bi2O3 is 3.0 eV.
Systematic Review and Meta-Analysis of Randomised, Other-than-Placebo Controlled, Trials of Individualised Homeopathic Treatment
Authors: Ulbrich-Zürni Susanne , Viksveen Petter , Roberts E. , Baitson Elizabeth , Legg Lynn , Davidson Jonathan , Mathie Robert 
Published: August 2018

Background This study focuses on randomised controlled trials (RCTs) of individualised homeopathic treatment (IHT) in which the control (comparator) group was other than placebo (OTP).
Aims To determine the comparative effectiveness of IHT on health-related outcomes in adults and children for any clinical condition that has been the subject of at least one OTP-controlled trial. For each study, to assess the risk of bias and to determine whether its study attitude was predominantly ‘pragmatic’ or ‘explanatory’.
Methods Systematic review. For each eligible trial, published in the peer-reviewed literature up to the end of 2015, we assessed its risk of bias (internal validity) using the seven-domain Cochrane tool, and its relative pragmatic or explanatory attitude (external validity) using the 10-domain PRECIS tool. We grouped RCTs by whether they examined IHT as an alternative treatment (study design Ia), adjunctively with another intervention (design Ib), or compared with a no-intervention group (design II). For each RCT, we identified a ‘main outcome measure’ to use in meta-analysis: ‘relative effect size’ was reported as odds ratio (OR; values >1 favouring homeopathy) or standardised mean difference (SMD; values < 0 favouring homeopathy).
Results Eleven RCTs, representing 11 different medical conditions, were eligible for study. Five of the RCTs (four of which in design Ib) were judged to have pragmatic study attitude, two were explanatory, and four were equally pragmatic and explanatory. Ten trials were rated ‘high risk of bias’ overall: one of these, a pragmatic study with design Ib, had high risk of bias solely regarding participant blinding (a bias that is intrinsic to such trials); the other trial was rated ‘uncertain risk of bias’ overall. Eight trials had data that were extractable for analysis: for four heterogeneous trials with design Ia, the pooled OR was statistically non-significant; collectively for three clinically heterogeneous trials with design Ib, there was a statistically significant SMD favouring adjunctive IHT; in the remaining trial of design 1a, IHT was non-inferior to fluoxetine in the treatment of depression.
Conclusions Due to the low quality, the small number and the heterogeneity of studies, the current data preclude a decisive conclusion about the comparative effectiveness of IHT. Generalisability of findings is limited by the variable external validity identified overall; the most pragmatic study attitude was associated with RCTs of adjunctive IHT. Future OTP-controlled trials in homeopathy should aim, as far as possible, to promote both internal validity and external validity.