bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spatial Coherence of Interplanetary Coronal Mass Ejection Sheaths at 1 AU
Authors: Ala‐Lahti Matti , Ruohotie Julia , Good Simon , Kilpua Emilia K. J. , Lugaz Noé 
Published: August 2020

AbstractThe longitudinal spatial coherence near 1 AU of the magnetic field in sheath regions driven by interplanetary coronal mass ejection (ICME) is studied by investigating ACE and Wind spacecraft measurements of 29 sheaths. During 2000–2002 Wind performed prograde orbits, and the non‐radial spacecraft separation varied from 0.001 to 0.012 AU between the studied events. We compare the measurements by computing the Pearson correlation coefficients for the magnetic field magnitude and components and estimate the magnetic field coherence by evaluating the scale lengths that give the extrapolated distance of zero correlation between the measurements. The correlation is also separately examined for low‐ and high‐pass filtered data. We discover magnetic fields in ICME sheaths have scale lengths that are larger than those reported in the solar wind but that, in general, are smaller than the ones of the ICME ejecta. Our results imply that magnetic fields in the sheath are more coherently structured and well correlated compared to the solar wind. The largest sheath coherence is reported in the GSE y‐direction that has the scale length of 0.149 AU while the lengths for Bx, Bz, and |B| vary between 0.024 and 0.035 AU. The same sheath magnitude ordering of scale lengths also apply for the low‐pass filtered magnetic field data. We discuss field line draping and the alignment of preexisting discontinuities by the shock passage giving reasoning for the observed results.
Spatial Extent of Quasiperiodic Emissions Simultaneously Observed by Arase and Van Allen Probes on 29 November 2018
Authors: Martinez‐Calderon C. , Němec F. , Katoh Y. , Shiokawa K. , Kletzing C. , Hospodarsky G. , Santolik O. , Kasahara Y. , Matsuda S. , Kumamoto A. , Tsuchiya F. , Matsuoka A. , Shoji M. , Teramoto M. , Kurita S. , Miyoshi Y. , Ozaki M. , Nishitani N. , Oinats A. V. , Kurkin V. I. 
Published: August 2020

AbstractRecent availability of a considerable amount of satellite and ground‐based data has allowed us to analyze rare conjugated events where extremely low and very low frequency waves from the same source region are observed in different locations. Here, we report a quasiperiodic (QP) emission, showing one‐to‐one correspondence, observed by three satellites in space (Arase and the Van Allen Probes) and a ground station. The main event was on 29 November 2018 from 12:06 to 13:08 UT during geomagnetically quiet times. Using the position of the satellites we estimated the spatial extent of the area where the one‐to‐one correspondence is observed. We found this to be up to 1.21 Earth's radii by 2.26 hr MLT, in radial and longitudinal directions, respectively. Using simple ray tracing calculations, we discuss the probable source location of these waves. At ∼12:20 UT, changes in the frequency sweep rate of the QP elements are observed at all locations associated with magnetic disturbances. We also discuss temporal changes of the spectral shape of QP observed simultaneously in space and on the ground, suggesting the changes are related to properties of the source mechanisms of the waves. This could be linked to two separate sources or a larger source region with different source intensities (i.e., electron flux). At frequencies below the low hybrid resonance, waves can experience attenuation and/or reflection in the magnetosphere. This could explain the sudden end of the observations at the spacecraft, which are moving away from the area where waves can propagate.
Hydromechanical Controls on the Spatiotemporal Patterns of Injection‐Induced Seismicity in Different Fault Architecture: Implication for 2013–2014 Azle Earthquakes
Authors: Chang K. W. , Yoon H. 
Published: August 2020

AbstractRecent observations of seismic events at the subsurface energy exploration sites show that spatial and temporal correlations sometimes do not match the spatial order of the known or detected fault location from the injection well. This study investigates the coupled flow and geomechanical control on the patterns of induced seismicity along multiple basement faults that show an unusual spatiotemporal relation with induced seismicity occurring in the far field first, followed by the near field. Two possible geological scenarios considered are (1) the presence of conductive hydraulic pathway within the basement connected to the distant fault (hydraulic connectivity) and (2) no hydraulic pathway, but the coexistence of faults with mixed polarity (favorability to slip) as observed at Azle, TX. Based on the Coulomb stability analysis and seismicity rate estimates, simulation results show that direct pore pressure diffusion through a hydraulic pathway to the distant fault can generate a larger number of seismicity than along the fault close to the injection well. Prior to pore pressure diffusion, elastic stress transfer can initiate seismic activity along the favorably oriented fault, even at the longer distance to the well, which may explain the deep 2013–2014 Azle earthquake sequences. This study emphasizes that hydrological and geomechanical features of faults will locally control poroelastic coupling mechanisms, potentially influencing the spatiotemporal pattern of injection‐induced seismicity, which can be used to infer subsurface architecture of fault/fracture networks.
Enhancing Accuracy of Air Quality and Temperature Forecasts During Paddy Crop Residue Burning Season in Delhi Via Chemical Data Assimilation
Authors: Kumar Rajesh , Ghude Sachin D. , Biswas Mrinal , Jena Chinmay , Alessandrini Stefano , Debnath Sreyashi , Kulkarni Santosh , Sperati Simone , Soni Vijay K. , Nanjundiah Ravi S. , Rajeevan M. 
Published: August 2020

AbstractThis paper examines the accuracy of Weather Research and Forecasting model coupled with Chemistry (WRF‐Chem) generated 72 hr fine particulate matter (PM2.5) forecasts in Delhi during the crop residue burning season of October‐November 2017 with respect to assimilation of the Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD) retrievals, persistent fire emission assumption, and aerosol‐radiation interactions. The assimilation significantly pushes the model AOD and PM2.5 toward the observations with the largest changes below 5 km altitude in the fire source regions (northeastern Pakistan, Punjab, and Haryana) as well as the receptor New Delhi. WRF‐Chem forecast with MODIS AOD assimilation, aerosol‐radiation feedback turned on, and real‐time fire emissions reduce the mean bias by 88–195 μg/m3 (70–86%) with the largest improvement during the peak air pollution episode of 6–13 November 2017. Aerosol‐radiation feedback contributes ~21%, ~25%, and ~24% to reduction in mean bias of the first, second, and third days of PM2.5 forecast. Persistence fire emission assumption is found to work really well, as the accuracy of PM2.5 forecasts driven by persistent fire emissions was only 6% lower compared to those driven by real fire emissions. Aerosol‐radiation feedback extends the benefits of assimilating satellite AOD beyond PM2.5 forecasts to surface temperature forecast with a reduction in the mean bias of 0.9–1.5°C (17–30%). These results demonstrate that air quality forecasting can benefit substantially from satellite AOD observations particularly in developing countries that lack resources to rapidly build dense air quality monitoring networks.
Efficiency and Accuracy of Micro‐Macro Models for Mineral Dissolution
Authors: Gärttner Stephan , Frolkovič Peter , Knabner Peter , Ray Nadja 
Published: August 2020

AbstractMicro‐macro models for dissolution processes are derived from detailed pore‐scale models applying upscaling techniques. They consist of flow and transport equations at the scale of the porous medium (macroscale). Both include averaged time‐ and space‐dependent coefficient functions (permeability, porosity, reactive surface, and effective diffusion). These are in turn explicitly computed from the time‐ and space‐dependent geometry of unit cells and by means of auxiliary cell problems defined therein (microscale). The explicit geometric structure is characterized by a level set. For its evolution, information from the transport equations solutions is taken into account (micro‐macro scales). A numerical scheme is introduced, which is capable of evaluating such complex settings. For the level‐set equation a second‐order scheme is applied, which enables us to accurately determine the dynamic reactive surface. Local mesh refinement methods are applied to evaluate Stokes type cell problems using P2/P1 elements and a Uzawa type linear solver. Applications of our permeability solver to scenarios involving static and evolving geometries are presented. Furthermore, macroscopic flow and transport equations are solved applying mixed finite elements. Finally, adaptive strategies to overcome the computational burden are discussed. We apply our approach to the dissolution of an array of dolomite grains in the micro‐macro context and validate our numerical scheme.
Mitigating the Impact of Irrigation With Effluent Water: Mixing With Freshwater and/or Adjusting Irrigation Management and Design
Authors: Assouline Shmuel , Kamai Tamir , Šimůnek Jiri , Narkis Kfir , Silber Avner 
Published: August 2020

AbstractThe use of treated wastewater (WW) for irrigation is steadily increasing worldwide. However, irrigation with WW requires special attention as it may alter soil hydraulic properties and, eventually, affect crop yields. The main goal of this study was to investigate two approaches that could mitigate this adverse impact: (i) mixing WW with local freshwater (FW) and (ii) adjusting the irrigation management and design to the deteriorated soil hydraulic properties. Four water qualities resulting from mixing FW and WW at different ratios for irrigation of an avocado orchard planted on a clayey soil were considered: FW, M1/3 (2/3 FW – 1/3 WW), M2/3 (1/3 FW ‐ 2/3 WW), and WW. Increasing the WW component in the irrigation water reduces the soil's saturated hydraulic conductivity and infiltrability, and this reduction is depth dependent. It also reduces the transpiration of trees and their trunk growth. This is supported by numerical simulations that showed that irrigation with WW produced the reduction in plant transpiration relative to irrigation with FW. Numerical simulations indicated that irrigation management and design could be adjusted to improve plant water uptake and reduce the differences due to water quality. The results indicate that decreasing the irrigation rate and increasing the wetted area per tree could increase the water uptake in WW‐irrigated soils to almost equal that in FW‐irrigated soils. This can be achieved by using drippers with lower discharge and by using more drippers per dripline, more driplines per tree, and more drippers per tree (concentric loops of driplines around each trunk).
Flow Channeling in Fracture Networks: Characterizing the Effect of Density on Preferential Flow Path Formation
Authors: Hyman Jeffrey D. 
Published: August 2020

AbstractFlow channelization is a commonly observed phenomenon in fractured subsurface media where the flow of fluids is restricted primarily to highly transmissive fracture networks surrounded by a low‐permeability rock matrix. The multiscale structural heterogeneity of these networks results in multiscale flow channelization where preferential flow paths form at length scales ranging from the entire system down to the subfracture size. We present an analysis of how one of the largest scales in fractured media, the network density, influences the degree of flow channeling that occurs using an ensemble of semigeneric three‐dimensional discrete fracture network (DFN) simulations. We construct 10 DFNs, whose fracture lengths follow a power law distribution, at four densities for a total of 40 networks. We characterize their structure in terms of the network topology and geometry. Eulerian and Lagrangian observations of the steady‐state flow fields obtained within the networks are used to quantify the degree of flow channelization at the network scale. We introduce a measure for the importance‐ranking/hierarchy of different flow paths in the network using graph‐based analysis of Lagrangian transport by which the degree of flow channeling between networks is compared. These flow observations are then linked to the structural properties of the networks. In general, network‐scale flow channeling decreases as the network density increases. However, at low densities, there is more uniform flow within the entire connected network than in high‐density networks. We also demonstrate how standard transport observables can be used to infer the degree of flow channelization occurring within a fracture network.
Distributed Acoustic Sensing as a Distributed Hydraulic Sensor in Fractured Bedrock
Authors: Becker M. W. , Coleman T. I. , Ciervo C. C. 
Published: August 2020

AbstractDistributed acoustic sensing (DAS) was originally intended to measure oscillatory strain at frequencies of 1 Hz or more on a fiber optic cable. Recently, measurements at much lower frequencies have opened the possibility of using DAS as a dynamic strain sensor in boreholes. A fiber optic cable mechanically coupled to a geologic formation will strain in response to hydraulic stresses in pores and fractures. A DAS interrogator can measure dynamic strain in the borehole, which can be related to fluid pressure through the mechanical compliance properties of the formation. Because DAS makes distributed measurements, it is capable of both locating hydraulically active features and quantifying the fluid pressure in the formation. We present field experiments in which a fiber optic cable was mechanically coupled to two crystalline rock boreholes. The formation was stressed hydraulically at another well using alternating injection and pumping. The DAS instrument measured oscillating strain at the location of a fracture zone known to be hydraulically active. Rock displacements of less than 1 nm were measured. Laboratory experiments confirm that displacement is measured correctly. These results suggest that fiber optic cable embedded in geologic formations may be used to map hydraulic connections in three‐dimensional fracture networks. A great advantage of this approach is that strain, an indirect measure of hydraulic stress, can be measured without beforehand knowledge of flowing fractures that intersect boreholes. The technology has obvious applications in water resources, geothermal energy, CO2 sequestration, and remediation of groundwater in fractured bedrock.
miR-16 integrates signal pathways in myofibroblasts: determinant of cell fate necessary for fibrosis resolution
Authors: Pan Qin , Guo Can-Jie , Xu Qing-Yang , Wang Jin-Zhi , Li Han , Fang Chun-Hua 
Published: August 2020

AbstractLiver fibrosis is characterized by the transdifferentiation of hepatic stellate cells (HSCs) to myofibroblasts and poor response to treatment. This can be attributed to the myofibroblast-specific resistance to phenotype reversal. In this study, we complemented miR-16 into miR-16-deficient myofibroblasts and analyzed the global role of miR-16 using transcriptome profiling and generating a pathway-based action model underlying transcriptomic regulation. Phenotypic analysis of myofibroblasts and fibrogenic characterization were used to understand the effect of miR-16 on phenotypic remodeling of myofibroblasts. miR-16 expression altered the transcriptome of myofibroblasts to resemble that of HSCs. Simultaneous targeting of Smad2 and Wnt3a, etc. by miR-16 integrated signaling pathways of TGF-β and Wnt, etc., which underlay the comprehensive regulation of transcriptome. The synergistic effect of miR-16 on the signaling pathways abolished the phenotypic characteristics of myofibroblasts, including collagen production and inhibition of adipogenesis. In vivo, myofibroblast-specific expression of miR-16 not only eliminated mesenchymal cells with myofibroblast characteristics but also restored the phenotype of HSCs in perisinusoidal space. This phenotypic remodeling resolved liver fibrosis induced by chronic wound healing. Therefore, miR-16 may integrate signaling pathways crucial for the fate determination of myofibroblasts. Its global effect induces the reversal of HSC-to-myofibroblast transdifferentiation and, subsequently, the resolution of fibrogenesis. Taken together, these findings highlight the potential of miR-16 as a promising therapeutic target for liver fibrosis.
LINC00675 activates androgen receptor axis signaling pathway to promote castration-resistant prostate cancer progression
Authors: Yao Mengfei , Shi Xiaolei , Li Yue , Xiao Yutian , Butler William , Huang Yongqiang , Du Leilei , Wu Tianqi , Bian Xiaojie , Shi Guohai , Ye Dingwei , Fu Guohui , Wang Jianhua , Ren Shancheng 
Published: August 2020

AbstractThe development of prostate cancer (PCa) from androgen-deprivation therapy (ADT) sensitive to castration resistant (CRPC) seriously impacts life quality and survival of PCa patients. Emerging evidence shows that long noncoding RNAs (lncRNAs) play vital roles in cancer initiation and progression. However, the inherited mechanisms of how lncRNAs participate in PCa progression and treatment resistance remain unclear. Here, we found that a long noncoding RNA LINC00675 was upregulated in androgen-insensitive PCa cell lines and CRPC patients, which promoted PCa progression both in vitro and in vivo. Knockdown of LINC00675 markedly suppressed tumor formation and attenuated enzalutamide resistance of PCa cells. Mechanistically, LINC00675 could directly modulate androgen receptor’s (AR) interaction with mouse double minute-2 (MDM2) and block AR’s ubiquitination by binding to it. Meanwhile, LINC00675 could bind to GATA2 mRNA and stabilize its expression level, in which GATA2 could act as a co-activator in the AR signaling pathway. Notably, we treated subcutaneous xenografts models with enzalutamide and antisense oligonucleotides (ASO) targeting LINC00675 in vivo and found that targeting LINC00675 would benefit androgen-deprivation-insensitive models. Our findings disclose that the LINC00675/MDM2/GATA2/AR signaling axis is a potential therapeutic target for CRPC patients.
TRPA1 mediates damage of the retina induced by ischemia and reperfusion in mice
Authors: Souza Monteiro de Araújo Daniel , De Logu Francesco , Adembri Chiara , Rizzo Stanislao , Janal Malvin N. , Landini Lorenzo , Magi Alberto , Mattei Gianluca , Cini Nicoletta , Pandolfo Pablo , Geppetti Pierangelo , Nassini Romina , Calaza Karin da Costa 
Published: August 2020

AbstractOxidative stress is implicated in retinal cell injury associated with glaucoma and other retinal diseases. However, the mechanism by which oxidative stress leads to retinal damage is not completely understood. Transient receptor potential ankyrin 1 (TRPA1) is a redox-sensitive channel that, by amplifying the oxidative stress signal, promotes inflammation and tissue injury. Here, we investigated the role of TRPA1 in retinal damage evoked by ischemia (1 hour) and reperfusion (I/R) in mice. In wild-type mice, retinal cell numbers and thickness were reduced at both day-2 and day-7 after I/R. By contrast, mice with genetic deletion of TRPA1 were protected from the damage seen in their wild-type littermates. Daily instillation of eye drops containing two different TRPA1 antagonists, an oxidative stress scavenger, or a NADPH oxidase-1 inhibitor also protected the retinas of C57BL/6J mice exposed to I/R. Mice with genetic deletion of the proinflammatory TRP channels, vanilloid 1 (TRPV1) or vanilloid 4 (TRPV4), were not protected from I/R damage. Surprisingly, genetic deletion or pharmacological blockade of TRPA1 also attenuated the increase in the number of infiltrating macrophages and in the levels of the oxidative stress biomarker, 4-hydroxynonenal, and of the apoptosis biomarker, active caspase-3, evoked by I/R. These findings suggest that TRPA1 mediates the oxidative stress burden and inflammation that result in murine retinal cell death. We also found that TRPA1 (both mRNA and protein) is expressed by human retinal cells. Thus, it is possible that inhibition of a TRPA1-dependent pathway could also attenuate glaucoma-related retinal damage.
Quick and seamless transition method for I‐f to sensorless vector control changeover and on‐the‐fly start of PMSM drives
Authors: Nair Sandeep V. , Hatua Kamalesh , Durga Prasad N.V.P.R. , Reddy D. Kishore 
Published: August 2020

A smooth changeover from the I‐f method to closed‐loop sensorless vector control is a critical requirement for permanent magnet synchronous motor (PMSM) drives using a back‐emf based sensorless algorithm for medium‐ to high‐speed range control. The existing methods provide a smooth transition by aligning the angle generated by I‐f control to the sensorless estimated angle. However, the overall start‐up time increases due to the additional transition interval, which limits the usability of these methods for applications requiring a quick start‐up. Furthermore, the use of a direct transition method to reduce the changeover time results in speed and current oscillation if the estimated position using sensorless algorithm is having an error. In the proposed method, the inverter pulses are disabled for a short duration and the machine back‐emf is measured after the stator current falls to zero. Therefore, a quick and seamless transition is achieved in the proposed method by accurately estimating the rotor position from the sensed back‐emf. The proposed method is also extended to perform on‐the‐fly start for power failure ride through during short time power supply interruption. The performance of the proposed method is verified using simulation and experiment on a 25 kW PMSM drive.
Investigation of scaling effect on power factor of permanent magnet Vernier machines for wind power application
Authors: Kana Padinharu Dileep Kumar , Li Guang‐Jin , Zhu Zi‐Qiang , Clark Richard , Azar Ziad , Thomas Arwyn 
Published: August 2020

This study investigates the scaling effect on power factor of surface mounted permanent magnet Vernier (SPM‐V) machines with power ratings ranging from 3 kW, 500 kW, 3 MW to 10 MW. For each power rating, different slot/pole number combinations have been considered to study the influence of key parameters including inter‐pole magnet leakage and stator slot leakage on power factor. A detailed analytical modelling, incorporating these key parameters, is presented and validated with two‐dimensional finite‐element analysis for different power ratings and slot/pole number combinations. The study has revealed that with scaling (increasing power level), significant increase in electrical loading combined with the increased leakage fluxes, i.e. (i) magnet leakage flux due to large coil pitch to rotor pole pitch ratio, (ii) magnet inter‐pole leakage flux and (iii) stator slot leakage flux, reduces the ratio of armature flux linkage to permanent magnet flux linkage and thereby has a detrimental effect on the power factor. Therefore, unlike conventional SPM machines, the power factor of SPM‐V machines is found to be significantly reduced at high power ratings.