bluuebunny/crossref_metadata_2025_split huggingface dataset:
Disturbances in Sporadic‐E During the Great Solar Eclipse of August 21, 2017
Authors: Chen G. , Wang J. , Reinisch B. W. , Li Y. , Gong W. 
Published: April 2021

AbstractThe great solar eclipse traveled eastward through the American Continent from coast to coast on August 21, 2017 and provided a rare opportunity to investigate the ionospheric responses to the rapid solar radiation variations. We have analyzed the peak electron density and density gradient variations in Sporadic E (Es) and applied the data of four Digisondes close to the eclipse path. All the four Digisondes have recorded the same interesting phenomena. One is the depletion on the fbEs (blanketing frequency of Es layer) curve during the solar eclipse and the other is the enhancements on the semi‐transparency parameter of Es layer Δf after the solar eclipse, where Δf = ftEs−fbEs, and ftEs is the top frequency of Es layer. The wind disturbances on the tidal wind and the photoionization decrease during the eclipse are put forward as a possible reason for the peak plasma density reduce. The periodic gravity waves have been observed in both ionospheric E and F region. However, the Δf enhancements occurred after the gravity waves had passed through the Es layer. Thus, we suggest that the solar induced waves did not raise the plasma density gradient directly. Gravity waves breaking may occur in the Mesosphere/Lower Thermosphere region to deposit momentum and produce turbulence, and so the accompanying instabilities may be generated to enhance the electron density gradient in E‐region.
A Modular Model of Jupiter's Magnetospheric Magnetic Field Based on Juno Data
Authors: Wang Jian‐zhao , Huo Zhuo‐xi , Zhang Lei 
Published: April 2021

AbstractAccurate modeling of Jupiter's magnetospheric magnetic field is important for not only scientific research but also mission planning. We develop a new empirical global model of Jupiter's magnetic field in the Juno era, including components from the planetary dynamo, Chapman‐Ferraro currents, and equatorial current sheet. The internal field is based on the JRM09 model. The shielding field is obtained by minimizing the component normal to Jupiter's magnetopause and varies due to the change of solar wind dynamic pressure. Combined with the curved magnetodisk, the high‐resolution TS07 method is used for modeling Jupiter's magnetodisc and tail currents. The best‐fitting results show an asymmetric magnetodisc current system in azimuthal direction with a tilted angle to Jupiter's magnetic equator. The sweep‐back effects of Jupiter's magnetic fields are also reproduced by the radial current system. This new model is validated by comparing with Juno's magnetometer data in the range from 5 Rj to 60 Rj, where Rj = 71,492 km is the radius of Jupiter.
Stagnant Slabs and Their Return Flows From Finite‐Frequency Tomography of the 410‐km and 660‐km Discontinuities
Authors: Guo Zhen , Zhou Ying 
Published: April 2021

AbstractSlab pull is generally considered as the dominant force that drives the global movement of tectonic plates. This convection mode is well constrained in the upper mantle but the convection pattern in the mid mantle is more speculative. In this study, we present high‐resolution global models of the 410‐km and 660‐km discontinuity structure from finite‐frequency tomography of SS precursors. The new models reveal a strong positive correlation between the two discontinuities under major subduction zones. In regions where large‐scale stagnant slabs have been reported in the mantle transition zone (MTZ), both discontinuities occur at depths greater than the global average. This structure correlates well with seismic wavespeed anomalies, suggesting possible return flows from the lower mantle warming up the shallow MTZ above the stagnant slabs. Using a simple model for stagnant slabs in geodynamical simulations, we show that this mode of mass exchange between the upper mantle and the lower mantle occurs predominantly in the vicinity of the slabs, and, the return flows become stronger as the extent of slab stagnation increases.
A Climatological View of Horizontal Ice Plates in Clouds: Findings From Nadir and Off‐Nadir CALIPSO Observations
Authors: Kikuchi M. , Okamoto H. , Sato K. 
Published: April 2021

AbstractWe study horizontal ice plates in clouds using satellite lidar measurements of the Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). This study investigates global microphysical and geographical properties of horizontal ice plates to obtain insights into ice‐plate climatology based on lidar’s long‐term measurements during 2006–2014. We then summarize the effects of the lidar's viewing angle change from 0.3° to 3.0° in 2007 on satellite particle phase/shape classifications. Using a classification algorithm developed in the previous studies, we show that the ice plate detection decreases by 81.7% due the tilting. With an updated version of this algorithm, 30.8% of these are recovered, although 50.8% remain undetected. Nevertheless, this study also shows that geographical characteristics of ice plates are still preserved during the off‐nadir period (within the remaining 50%), suggesting the undiscovered climatological information on ice plates in the post‐2007 observations. According to our analysis, the tilting mainly affects horizontal ice plate detection, while the impacts on water and randomly oriented ice detections are limited. The temperature of the ice plates ranges from −25.5°C and −7.5°C, with a mode temperature of −13.5°C, although the ice plates also occur ubiquitously across mid‐ to high‐latitudes between −20°C and −40°C, which is much colder than what found in previous nadir studies. This study offers a detailed discussion on the fundamental characteristics of horizontal ice plates that will provide robust information for the algorithm preparation for future satellite lidar observations such as the Earth, Clouds, Aerosol and Radiation Explorer (EarthCARE).
Hilltop Curvature Increases With the Square Root of Erosion Rate
Authors: Gabet E. J. , Mudd S. M. , Wood R. W. , Grieve S. W. D. , Binnie S. A. , Dunai T. J. 
Published: April 2021

AbstractThe shape of soil‐mantled hillslopes is typically attributed to erosion rate and the transport efficiency of the various processes that contribute to soil creep. While climate is generally hypothesized to have an important influence on soil creep rates, a lack of uniformity in the measurement of transport efficiency has been an obstacle to evaluating the controls on this important landscape parameter. We addressed this problem by compiling a data set in which the transport efficiency has been calculated using a single method, the analysis of hilltop curvatures using 1‐m LiDAR data, and the erosion rates have also been determined via a single method, in‐situ cosmogenic 10Be concentrations. Moreover, to control for lithology, we chose sites that are only underlain by resistant bedrock. The sites span a range of erosion rates (6–922 mm/kyr), mean annual precipitation (39–320 cm/yr), and aridity index (0.08–1.38). Surprisingly, we find that hilltop curvature varies with the square root of erosion rate, whereas previous studies predict a linear relationship. In addition, we find that the inferred transport coefficient also varies with the square root of erosion rate but is insensitive to climate. We explore various mechanisms that might link the transport coefficient to the erosion rate and conclude that present theory regarding soil‐mantled hillslopes is unable to explain our results and is, therefore, incomplete. Finally, we tentatively suggest that processes occurring in the bedrock (e.g., fracture generation) may play a role in the shape of hillslope profiles at our sites.
Joint Inversion for Surface Accumulation Rate and Geothermal Heat Flow From Ice‐Penetrating Radar Observations at Dome A, East Antarctica. Part I: Model Description, Data Constraints, and Inversion Results
Authors: Wolovick M. J. , Moore J. C. , Zhao L. 
Published: April 2021

AbstractIce‐penetrating radar data contain a wealth of information about the bed and internal structure of the ice sheet. While these data have long been used to diagnose the presence of basal water, infer attenuation rates, or explore the internal stratigraphy of the ice sheet, they have rarely been used jointly in a formal inverse model for the ice sheet temperature structure. Here, we invert a coupled thermomechanical ice sheet and basal hydrology model to infer both geothermal heat flow (GHF) and accumulation rate from multiple classes of radar observations in the area around Dome A, East Antarctica. Our forward model solves for a coupled steady state between the ice sheet flow field, temperature, and basal hydrology, including melt, water transport, and freeze‐on. We fit radar observations of basal water, freeze‐on, and internal layers, along with a GHF prior based on aeromagnetic observations. We minimize the combined misfit function by first using an evolutionary algorithm followed by localized perturbation tests. In addition to inferring the spatial distribution of GHF and accumulation rate, we are also able to estimate the uncertainty about our best‐fit answer, as well as quantify how our result depends on each individual data constraint. Our results demonstrate a new method for combining multiple glaciological constraints into a single inverse model of the ice sheet, and give us a more rigorous picture of the information content provided by each data set. In a companion paper we analyze and interpret the best‐fit model.
The Tuning Strategy of IPSL‐CM6A‐LR
Authors: Mignot Juliette , Hourdin Frédéric , Deshayes Julie , Boucher Olivier , Gastineau Guillaume , Musat Ionela , Vancoppenolle Martin , Servonnat Jérôme , Caubel Arnaud , Chéruy Frédérique , Denvil Sébastien , Dufresne Jean‐Louis , Ethé Christian , Fairhead Laurent , Foujols Marie‐Alice , Grandpeix Jean‐Yves , Levavasseur Guillaume , Marti Olivier , Menary Matthew , Rio Catherine , Rousset Clément , Silvy Yona 
Published: April 2021

AbstractThe assessment of current and future risks for natural and human systems associated with climate change largely relies on numerical simulations performed with state‐of‐the‐art climate models. Various steps are involved in the development of such models, from development of individual components of the climate system up to free parameter calibration of the fully coupled model. Here, we describe the final tuning phase for the IPSL‐CM6A‐LR climate model. This phase alone lasted more than 3 years and relied on several pillars: (i) the tuning against present‐day conditions given a small adjustment of the ocean surface albedo to compensate for the current oceanic heat uptake, (ii) the release of successive versions after adjustments of the individual components, implying a systematic and recurrent adjustment of the atmospheric energetics, and (iii) the use of a few metrics based on large scale variables such as near‐global mean temperature, summer Arctic sea‐ice extent, as targets for the tuning. Successes, lessons and prospects of this tuning strategy are discussed.
A Detection Performance Analysis of Sanya Incoherent Scatter Radar Tristatic System
Authors: Zhang Ning , Li Mingyuan , Zhao Biqiang , Zeng Lingqi , Yue Xinan , Hao Honglian , Wang Junyi , Ding Feng , Ning Baiqi , Wan Weixing 
Published: April 2021

AbstractIncoherent scatter radars (ISR) are among the most powerful ground‐based instruments for solar‐terrestrial physics, measuring multiple plasma parameters over almost the entire vertical extent of the ionosphere. In Sanya, on Hainan Island, China, an advanced high‐power phased array ISR, known as the Sanya incoherent scatter radar (SYISR), is under construction. A tristatic system is planned, with a transmitter at Sanya (SY) Station (109.6°E, 18.3°N), together with receivers at SY, Fuke (FK) (109.1°E, 19.5°N), and Qiongshan (QS) (110.2°E, 19.7°N) on Hainan Island. With the pulse width increasing, the SNR increases for a phased array monostatic ISR, while the SNR initially increases and then remains unchanged for a phased array bistatic ISR. SNR first increases and then decreases as the detection height increases from 100 km to 1,000 km for both the monostatic and bistatic ISR for typical ionospheric conditions. The relative error decreases fast with increasing pulse width when the pulse width is lower than 130 μs for both monostatic and bistatic ISR. When the pulse width is over 130 μs, the relative error decreases very slowly for a monostatic ISR, while it decreases very slowly and then stays unchanged with increasing pulse width for a bistatic ISR. Relative error increases slowly below 500 km, but increases fast for heights over 500 km for both the monostatic ISR and bistatic ISR. It is shown that a tilt angle of 20°–30° and a clockwise‐rotation angle of 157° are reasonable choices for the FK receiving array in the SYISR tristatic system.
Exploring Contingency Skill Scores Based on Event Sizes
Authors: Kahler S. W. , Darsey H. 
Published: April 2021

AbstractSpace weather forecasts are generally made for events with an arbitrary size threshold imposed on an event statistical size distribution which is likely described by a power law. This is the case for solar energetic (E > 10 MeV) particle (SEP) events, which have a differential power law exponent of γ = 1.2. Event forecasts are usually evaluated by skill scores using a contingency table that matches the forecasted events against observed events independently of the event sizes. Each observed event is either a forecasted hit or a miss, and each forecasted event is either an observed hit or a false alarm. However, for SEP events and most other space weather parameters the event size is a critical factor for the user. It is more important that large events be well forecasted than threshold events. In addition, false alarms may be useful when they match observed events just below the forecast threshold. We explore a forecast evaluation scheme to incorporate the event size within the usual format of a binary contingency table to evaluate model performance. The scheme is applied to three different input options of a recently published evaluation of the Proton Prediction System (PPS) for SEP events to show differences between numbers‐based and intensity‐based skill scores of the PPS. We demonstrate how identical skill scores can result from models with extremely different performances of event intensity forecasts. The scheme requires model validation and would benefit from testing with other space weather applications.
Feedback From Vegetation to Interannual Variations of Indian Summer Monsoon Rainfall
Authors: Budakoti Sachin , Chauhan Tejasvi , Murtugudde Raghu , Karmakar Subhankar , Ghosh Subimal 
Published: April 2021

AbstractInterannual variations of Indian summer monsoon rainfall (ISMR) are modulated by external forcings such as El Niño Southern Oscillation, Indian Ocean Dipole, and the Atlantic Niño. Vegetation over land responds to variations in ISMR, but the feedback from vegetation to ISMR variability has not been fully explored yet. To address this gap, we perform two simulations with the regional Weather Research and Forecasting model coupled to the Community Land Surface Model (WRF‐CLM) for the period of 2004–2018. We use the same boundary forcing from ERA‐interim reanalysis for the two experiments, but with two different vegetation prescriptions, (1) observed, interannually varying Leaf Area Index (LAI), obtained from satellite images/data (VAR‐LAI); and (2) climatological Leaf Area Index from the same product, to suppress interannual LAI variations (CLIM‐LAI). We find that the correlation coefficient of simulated total seasonal rainfall with the observed data is higher for VAR‐LAI simulation as compared to CLIM‐LAI. To elicit causality among eco‐hydro‐climatological variables, we develop a network based on information theory, i.e., a process network. We find that LAI plays a major role in influencing precipitation in the network through evapotranspiration. The number of links originating from LAI and evapotranspiration increases during drought years, making the eco‐hydro‐climatological network denser. Our findings indicate that the ISMR predictions and projections need to represent the time‐varying LAI to fully capture the varying feedbacks from evolving vegetation to the atmosphere especially during drought years.
Diurnal Variations of Size‐Resolved Bioaerosols During Autumn and Winter Over a Semi‐Arid Megacity in Northwest China
Authors: Yang Liu , Shen Zhenxing , Wang Diwei , Wei Junqiang , Wang Xin , Sun Jian , Xu Hongmei , Cao Junji 
Published: April 2021

AbstractBioaerosols have a major negative effect on air quality and on public health by causing the spread of diseases. This study evaluated the bioaerosol composition and variation in a semi‐arid megacity of northwest China from October 2019 to January 2020 using an Andersen six‐stage impactor sampler. The size distribution, diurnal variations of the concentrations of airborne bacteria, airborne fungi, and total airborne microbes (TAM) were investigated in autumn and winter. The mean concentrations of airborne bacteria, fungi, and TAM were 523.5 ± 301.1 colony‐forming units (CFU)/m3, 1318.9 ± 447.8 CFU/m3, and (7.25 ± 1.90) × 106 cells/m3, respectively, in autumn and 581 ± 305.4 CFU/m3, 1234.4 ± 519.9 CFU/m3, and (5.96 ± 1.65) × 106 cells/m3, respectively, in winter. The mean bioaerosol concentrations were slightly higher on nonhaze days than on haze days, but the difference was not statistically significant. Higher ambient particulate matter levels and atmospheric oxidation capacity inhibited bacteria survival. The diurnal maximum bioaerosol concentration was observed in the morning in autumn, whereas in winter, bioaerosols did not exhibit such a distribution, the impact of human activities on bioaerosols was still uncertain. The size of airborne bacteria exhibited a bimodal distribution, whereas a unimodal pattern was observed for fungi and TAM. Most bacteria, fungi, and TAM were distributed in the respirable ranges from trachea and primary bronchi to alveoli, indicating that bioaerosols have a high risk of being inhaled and causing respiratory diseases in Xi’an.
Precision modeling of gall bladder cancer patients in mice based on orthotopic implantation of organoid-derived tumor buds
Authors: Kato Shingo , Fushimi Kentaro , Yabuki Yuichiro , Maru Yoshiaki , Hasegawa Sho , Matsuura Tetsuya , Kurotaki Daisuke , Suzuki Akihiro , Kobayashi Noritoshi , Yoneda Masato , Higurashi Takuma , Enaka Makiko , Tamura Tomohiko , Hippo Yoshitaka , Nakajima Atsushi 
Published: April 2021

AbstractGenetically engineered mice (GEM) are the gold standard for cancer modeling. However, strict recapitulation of stepwise carcinogenesis from a single tumor-initiating epithelial cell among genetically intact cells in adults is not feasible with the currently available techniques using GEM. In previous studies, we partially overcame this challenge by physically isolating organs from adult animals, followed by genetic engineering in organoids and subcutaneous inoculation in nude mice. Despite the establishment of suitable ex vivo carcinogenesis models for diverse tissues, tumor development remained ectopic and occurred under immunodeficient conditions. Further refinement was, therefore, necessary to establish ideal models. Given the poor prognosis and few models owing to the lack of gall bladder (GB)-specific Cre strain, we assumed that the development of authentic models would considerably benefit GB cancer research. Here, we established a novel model using GB organoids with mutant Kras and Trp53 loss generated in vitro by lentiviral Cre transduction and CRISPR/Cas9 gene editing, respectively. Organoid-derived subcutaneous tumor fragments were sutured to the outer surface of the GB in syngeneic mice, which developed orthotopic tumors that resembled human GB cancer in histological and transcriptional features. This model revealed the infiltration of similar subsets of immune cells in both subcutaneous and orthotopic tumors, confirming the appropriate immune environment during carcinogenesis. In addition, we accurately validated the in vivo efficacy of gemcitabine, a common therapeutic agent for GB cancer, in large cohorts. Taken together, this model may serve as a promising avatar of patients with GB cancer in drug discovery and precision medicine.
Mendelian randomization integrating GWAS and eQTL data revealed genes pleiotropically associated with major depressive disorder
Authors: Yang Huarong , Liu Di , Zhao Chuntao , Feng Bowen , Lu Wenjin , Yang Xiaohan , Xu Minglu , Zhou Weizhu , Jing Huiquan , Yang Jingyun 
Published: April 2021

AbstractPrevious genome-wide association studies (GWAS) have identified potential genetic variants associated with the risk of major depressive disorder (MDD), but the underlying biological interpretation remains largely unknown. We aimed to prioritize genes that were pleiotropically or potentially causally associated with MDD. We applied the summary data-based Mendelian randomization (SMR) method integrating GWAS and gene expression quantitative trait loci (eQTL) data in 13 brain regions to identify genes that were pleiotropically associated with MDD. In addition, we repeated the analysis by using the meta-analyzed version of the eQTL summary data in the brain (brain-eMeta). We identified multiple significant genes across different brain regions that may be involved in the pathogenesis of MDD. The prime-specific geneBTN3A2(corresponding probe: ENSG00000186470.9) was the top hit showing pleiotropic association with MDD in 9 of the 13 brain regions and in brain-eMeta, after correction for multiple testing. Many of the identified genes are located in the human major histocompatibility complex (MHC) region on chromosome 6 and are mainly involved in the immune response. Our SMR analysis indicated that multiple genes showed pleiotropic association with MDD across the brain regions. These findings provided important leads to a better understanding of the mechanism of MDD and revealed potential therapeutic targets for the prevention and effective treatment of MDD.
FGF23 ameliorates ischemia-reperfusion induced acute kidney injury via modulation of endothelial progenitor cells: targeting SDF-1/CXCR4 signaling
Authors: Chang Huang-Ming , Peng Kang-Yung , Chan Chieh-Kai , Sun Chiao-Yin , Chen Ying-Ying , Chang Han-Mei , Huang Chun-Lin , Liu Pei-Chun , Chen Peng-Ying , Wang Kuo-Chuan , Wang Wei-Jie , Wu Chen-Chi , Lin Yu-Feng , Lai Tai-Shuan , Huang Tao-Min , Young Guang-Huar , Lin Shuei-Liong , Ostermann Marlies , Chu Tzong-Shinn , Chueh Jeff S. , Wu Vin-Cent 
Published: April 2021

AbstractThe levels of fibroblast growth factor 23 (FGF23) rapidly increases after acute kidney injury (AKI). However, the role of FGF23 in AKI is still unclear. Here, we observe that pretreatment with FGF23 protein into ischemia-reperfusion induced AKI mice ameliorates kidney injury by promoting renal tubular regeneration, proliferation, vascular repair, and attenuating tubular damage. In vitro assays demonstrate that SDF-1 induces upregulation of its receptor CXCR4 in endothelial progenitor cells (EPCs) via a non-canonical NF-κB signaling pathway. FGF23 crosstalks with the SDF-1/CXCR4 signaling and abrogates SDF-1-induced EPC senescence and migration, but not angiogenesis, in a Klotho-independent manner. The downregulated pro-angiogenic IL-6, IL-8, and VEGF-A expressions after SDF-1 infusion are rescued after adding FGF23. Diminished therapeutic ability of SDF-1-treated EPCs is counteracted by FGF23 in a SCID mouse in vivo AKI model. Together, these data highlight a revolutionary and important role that FGF23 plays in the nephroprotection of IR-AKI.