bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved 3‐D P Wave Azimuthal Anisotropy Structure Beneath the Tokyo Metropolitan Area, Japan: New Interpretations of the Dual Subduction System Revealed by Seismic Anisotropy
Authors: Ishise Motoko , Kato Aitaro , Sakai Shin'ichi , Nakagawa Shigeki , Hirata Naoshi 
Published: March 2021

AbstractThe Tokyo metropolitan area, in the Kanto region of Japan, lies on the Okhotsk plate. Historically, the city has suffered severe damage as a result of megathrust ruptures and intra‐plate earthquakes (M ≥ 7) caused by the dual subduction of the Philippine Sea (PHS) slab and the Pacific slab. To understand the unique seismotectonics of the region, we constrain the three‐dimensional (3‐D) P wave isotropic and azimuthal anisotropic velocity structure beneath the Kanto district, by applying a high‐resolution anisotropic tomography method to travel time data from a dense seismic network consisting of ∼500 stations (including the Metropolitan Seismic Observation network, MeSO‐net). The seismic structure, derived from 1,877 local earthquakes, suggests that the basement of the Okhotsk plate consists of an old accretionary zone formed when the NE Japan arc was part of the Asian continent. The anisotropy observed in the oceanic crust of the subducting PHS slab suggests the presence of a well‐developed system of bending‐related faults, oriented parallel to the axis of the Sagami Trough. We identify a low‐velocity anomaly within the PHS slab mantle, located beneath the Boso Peninsula, which has previously been interpreted as representing the overlying continental plate or the oceanic crust of the PHS slab. Lateral variations in the anisotropy structure suggest that the NE limit of the PHS slab lies farther south than previously thought. Anisotropy directions can be used to identify heterogeneities embedded in low‐velocity anomalies within the PHS slab, which have not been identified in previous studies using only isotropic velocity models.
Comment on “Increasing Rates of Carbon Burial in Southwest Florida Coastal Wetlands” by J. Breithaupt et al.
Authors: Parkinson Randall W. 
Published: March 2021

AbstractIn a recent study, Breithaupt et al. (2020); https://doi.org/10.1029/2019JG005349 contend observed rates of sediment and organic carbon accumulation in Southwest Florida coastal wetlands have increased in response to an acceleration in the rate of sea‐level. This, it is argued, implies the wetlands are more resilient to future sea‐level rise than previously thought and under conditions of continued acceleration, even more organic carbon will be stored. However, upon closer inspection, the study conclusions are flawed as they are based upon an inappropriate methodological approach to quantifying sediment and organic carbon accumulation rates and require an acceleration in the rate of historical (decades) sea‐level rise of which there is limited evidence and no broad consensus.
Assessing Sedimentary Detrital Pb Isotopes as a Dust Tracer in the Pacific Ocean
Authors: Erhardt Andrea M. , Douglas Grant , Jacobson Andrew D. , Wimpenny Josh , Yin Qing‐Zhu , Paytan Adina 
Published: March 2021

AbstractMineral dust particles from different source regions typically have distinct Pb isotope ratios. Theoretically, Pb isotopic composition of terrigenous minerals isolated from open‐ocean sediments should allow for dust provenance reconstructions. However, Pb isotopes of terrigenous fractions of sediments have frequently been inconsistent with expected source region signatures. This study investigates the reason(s) for offsets between the Pb isotope values of the dust component in sediment cores and those expected from source regions with focus on changes in sediment composition, sediment age, and sediment processing for analysis. Pb isotope ratios from Pacific Ocean core‐top sediments show a general delineation of the Intertropical Convergence Zone (ITCZ). Isotope mixing models support these general trends, though similarity in Pb isotope ratios of disparate source regions makes constraining specific sources challenging. Pb isotope ratios in downcore samples varied on glacial/interglacial time scales, being less radiogenic during the last glacial maximum, suggesting either a weakened ITCZ or the addition of a new, less radiogenic, source to the system. Finally, Pb isotope ratios in some source region samples yielded different Pb isotope signatures in bulk source sample than in the insoluble terrigenous fraction of the source sample, indicating that differential mineral preservation within the terrigenous component in sediments may cause offsets from source signatures. Overall, while Pb isotopes show distinct basin‐scale variations, high‐resolution spatial reconstructions require tight age controls and consistency in analytical treatment if used to define ocean sediment source regions.
Formation and Forward Propagation of the Indosinian Foreland Fold‐Thrust Belt and Nanpanjiang Foreland Basin in SW China
Authors: Yang Wen‐Xin , Yan Dan‐Ping , Qiu Liang , Wells Michael L. , Dong Jian‐Meng , Gao Tian , Zhang Zhi , Mu Hongxu , Wang Xinwen , Wang Fangyue 
Published: March 2021

AbstractOrogenic growth, characterized by formation and forward propagation of fold‐thrust belts and foreland basins, is predicted by wedge models of thrust systems. The growth of the Nanpanjiang fold‐thrust belt and foreland basin system of the Indosinian orogenic belt in the southwestern South China remains poorly understood. The development of the Indosinian foreland system remains underappreciated due to few constraints on structural styles, kinematics and ages. Surface cross sections, seismic profiles and detrital zircon data are presented to address the structural styles and evolution of the Indosinian foreland system. The results reveal that the fold‐thrust belt is characterized by fault‐related folds with deeper duplexes and shallower imbricates, which yield a NNE‐SSW regional shortening magnitude of ∼36%. Our new constraints indicate that the Nanpanjiang region experienced multi‐staged thrusting during the Indosinian orogeny (D1). The D11affected the southernmost southern fold‐thrust belt, producing thick‐skinned thrusts involving Neoproterozoic basement and initiating the Nanpanjiang foreland basin. During the D12, NNE‐verging thick‐skinned thrusting continued and was followed by thin‐skinned thrusting in the northern fold‐thrust belt. Locally preserved foreland basin deposits at the northernmost Nanpanjiang Basin define D13. The progressive D14co‐axially deformed the residual basin into a wide and gentle syncline. Thus, the progressive D11to D14deformation sequence of NNE‐verging in‐sequence thrusting and foreland basin migration describe the kinematic and dynamic relationship between fold‐thrust belt and foreland basin during the Indosinian tectonic event. Indosinian D1structures were subsequently refolded by the Yanshanian tectonic event (D2), forming N‐ to NE‐striking cleavage and arcuation of D1fold axes.
A Framework for Untangling Transient Groundwater Mixing and Travel Times
Authors: Popp Andrea L. , Pardo‐Álvarez Álvaro , Schilling Oliver S. , Scheidegger Andreas , Musy Stéphanie , Peel Morgan , Brunner Philip , Purtschert Roland , Hunkeler Daniel , Kipfer Rolf 
Published: March 2021

AbstractUnderstanding the mixing between surface water and groundwater as well as groundwater travel times in vulnerable aquifers is crucial to sustaining a safe water supply. Age dating tracers used to infer apparent travel times typically refer to the entire groundwater sample. A groundwater sample, however, consists of a mixture of waters with a distribution of travel times. Age dating tracers only reflect the proportion of the water that is under the dating range of the used tracer, thus their interpretation is typically biased. Additionally, end‐member mixing models are subject to various sources of uncertainties, which are typically neglected. In this study, we introduce a new framework that untangles groundwater mixing ratios and travel times using a novel combination of in‐situ noble gas analyses. We applied this approach during a groundwater pumping test carried out in a pre‐alpine Swiss valley. First, we calculated transient mixing ratios between recently infiltrated river water and regional groundwater present in a wellfield, using helium‐4 concentrations combined with a Bayesian end‐member mixing model. Having identified the groundwater fraction of recently infiltrated river water (Frw) consequently allowed us to infer the travel times from the river to the wellfield, estimated based on radon‐222 activities of Frw. Furthermore, we compared tracer‐based estimates of Frw with results from a calibrated numerical model. We demonstrate (i) that partitioning of major water sources enables a meaningful interpretation of an age dating tracer of the water fraction of interest and (ii) that the streambed has a major control on the estimated travel times.
Assessing the Precision of Total Contributing Area (TCA) Estimated by Flow Direction Algorithms Based on the Analytical Solution of Theoretical TCA on Synthetic Surfaces
Authors: Li Zhenya , Yang Tao , Wang Chao , Shi Pengfei , Yong Bin , Song Ying 
Published: March 2021

AbstractTotal contributing area (TCA) has important hydrological, geological, and geomorphological implications in digital terrain analysis. Currently, the validity of estimated TCA is challenged by the approximation error of digital elevation models (DEMs) to real‐world terrains, the choice of flow direction algorithms and the difficulty in a quantitative evaluation. To solve these problems, this work employs a range of synthetic surfaces for free from approximation errors. Theoretical TCA for any cell on synthetic surfaces is analytically solved by using subsection integral and L'Hospital’s rule based on the topographical definition of TCA. The impacts of grid discretization on the spatial patterns of theoretical TCA are explained mathematically and geometrically. In case studies, the analytically solved theoretical TCA is treated as a benchmark to quantitatively evaluate the TCAs estimated by three SFD algorithms (i.e., D8, Rho8, and D8‐LTD) and three MFD algorithms (i.e., FDFM, MFD‐md, and D∞). Results show that (1) SFD algorithms obtain unsmooth and discontinuous spatial patterns of estimated TCA, due to the existence of source cells caused by the basic hypothesis of allowing only one receiving cell; (2) Cross compensation induced by artificial dispersion in MFD algorithms leads to a less error in the quantity of estimated TCA but a larger error in the physical position of estimated TCA; (3) The addition of contour length errors does not promise larger specific contributing area errors than TCA errors. To summarize, this work offers a theoretical and quantitative evaluation on the precision of the TCAs estimated by flow direction algorithms.
Improving the Representation of Long‐Term Storage Variations With Conceptual Hydrological Models in Data‐Scarce Regions
Authors: Hulsman Petra , Hrachowitz Markus , Savenije Hubert H. G. 
Published: March 2021

AbstractIn the Luangwa basin in Zambia, long‐term total water storage variations were observed with Gravity Recovery and Climate Experiment, but not reproduced by a standard conceptual hydrological model that encapsulates our current understanding of the dominant regional hydrological processes. The objective of this study was to identify potential processes underlying these low‐frequency variations through combined data analysis and model hypothesis testing. First, we analyzed the effect of data uncertainty by contrasting observed storage variations with multi‐annual estimates of precipitation and evaporation from multiple data sources. Second, we analyzed four different combinations of model forcing and evaluated their skill to reproduce the observed long‐term storage variations. Third, we formulated alternative model hypotheses for groundwater export to potentially explain low‐frequency storage variations. Overall, the results suggest that the initial model's inability to reproduce the observed low‐frequency storage variations was partly due to the forcing data used and partly due to the missing representation of regional groundwater export. More specifically, the choice of data source affected the model's ability to reproduce annual maximum storage fluctuations, whereas the annual minima improved by adapting the model structure to allow for groundwater export from a deeper groundwater layer. This suggests that, in contrast to previous research, conceptual models can reproduce long‐term storage fluctuations if a suitable model structure is used. Overall, the results highlight the value of alternative data sources and iterative testing of model structural hypotheses to improve runoff predictions in a poorly gauged basin leading to enhanced understanding of its hydrological processes.
Single Particle Multipole Expansions From Micromagnetic Tomography
Authors: Cortés‐Ortuño David , Fabian Karl , de Groot Lennart V. 
Published: March 2021

AbstractMicromagnetic tomography aims at reconstructing large numbers of individual magnetizations of magnetic particles from combining high‐resolution magnetic scanning techniques with micro X‐ray computed tomography (microCT). Previous work demonstrated that dipole moments can be robustly inferred, and mathematical analysis showed that the potential field of each particle is uniquely determined. Here, we describe a mathematical procedure to recover higher orders of the magnetic potential of the individual magnetic particles in terms of their spherical harmonic expansions (SHE). We test this approach on data from scanning superconducting quantum interference device microscopy and microCT of a reference sample. For particles with high signal‐to‐noise ratio of the magnetic scan we demonstrate that SHE up to order n = 3 can be robustly recovered. This additional level of detail restricts the possible internal magnetization structures of the particles and provides valuable rock magnetic information with respect to their stability and reliability as paleomagnetic remanence carriers. Micromagnetic tomography therefore enables a new approach for detailed rock magnetic studies on large ensembles of individual particles.
Effects of Using High Resolution Satellite‐Based Inundation Time Series to Estimate Methane Fluxes From Forested Wetlands
Authors: Hondula Kelly L. , DeVries Ben , Jones C. Nathan , Palmer Margaret A. 
Published: March 2021

AbstractA major source of uncertainty in the global methane budget arises from quantifying the area of wetlands and other inland waters. This study addresses how the dynamics of surface water extent in forested wetlands affect the calculation of methane emissions. We used fine resolution satellite imagery acquired at sub‐weekly intervals together with a semiempirical methane emissions model to estimate daily surface water extent and diffusive methane fluxes for a low‐relief wetland‐rich watershed. Comparisons of surface water model predictions to field measurements showed agreement with the magnitude of changes in water extent, including for wetlands with surface area less than 1,000 m2. Results of methane emission models showed that wetlands smaller than 1 hectare (10,000 m2) were responsible for a majority of emissions, and that considering dynamic inundation of forested wetlands resulted in 49%–62% lower emission totals compared to models using a single estimate for each wetland’s size.
Does Dynamic Downscaling Modify the Projected Impacts of Stabilized 1.5°C and 2°C Warming on Hot Extremes Over China?
Authors: Ge Jun , Qiu Bo , Wu Runqi , Cao Yipeng , Zhou Weidan , Guo Weidong , Tang Jianping 
Published: March 2021

AbstractUsing Weather Research and Forecasting (WRF) model, we perform the first dynamic downscaling of Community Earth System Model (CESM) Low‐Warming simulations to examine hot extreme changes over China in response to stabilized 1.5°C and 2°C global warming. WRF projects more intense and frequent hot extremes due to global warming, which are qualitatively consistent with CESM. However, WRF and CESM significantly differ in magnitudes of hot extreme changes. Compared to CESM, WRF indicates larger increases in hot extremes over Tibetan Plateau but smaller increases over other regions. Such differences between WRF and CESM are mainly caused by divergent projections of shortwave radiation changes. WRF also suggests fewer benefits achieved from the additional 0.5°C warming constraint than CESM. This study demonstrates the climate risks might be inadequately informed by global climate models and it is necessary to reevaluate impacts of 1.5°C and 2°C global warming on regional climate based on regional climate models.
Cancer-associated fibroblast-derived CXCL11 modulates hepatocellular carcinoma cell migration and tumor metastasis through the circUBAP2/miR-4756/IFIT1/3 axis
Authors: Liu Gao , Sun Jian , Yang Zhang-Fu , Zhou Cheng , Zhou Pei-Yun , Guan Ruo-Yu , Sun Bao-Ye , Wang Zhu-Tao , Zhou Jian , Fan Jia , Qiu Shuang-Jian , Yi Yong 
Published: March 2021

AbstractCancer-associated fibroblasts (CAFs) are commonly acquired activated extracellular matrix (ECM)-producing myofibroblasts, a phenotypes with multiple roles in hepatic fibrogenesis and carcinogenesis via crosstalk with cohabitating stromal/cancer cells. Here, we discovered a mechanism whereby CAF-derived cytokines enhance hepatocellular carcinoma (HCC) progression and metastasis by activating the circRNA-miRNA-mRNA axis in tumor cells. CAFs secreted significantly higher levels of CXCL11 than normal fibroblasts (NFs), and CXCL11 also had comparatively higher expressions in HCC tissues, particularly in metastatic tissues, than para-carcinoma tissues. Both CAF-derived and experimentally introduced CXCL11 promoted HCC cell migration. Likewise, CAFs promoted tumor migration in orthotopic models, as shown by an increased number of tumor nodules, whereas CXCL11 silencing triggered a decrease of it. CXCL11 stimulation upregulated circUBAP2 expression, which was significantly higher in HCC tissues than para-carcinoma tissues. Silencing circUBAP2 reversed the effects of CXCL11 on the expression of IL-1β/IL-17 and HCC cell migration. Further downstream, the IFIT1 and IFIT3 levels were significantly upregulated in HCC cells upon CXCL11 stimulation, but downregulated upon circUBAP2 silencing. IFIT1 or IFIT3 silencing reduced the expression of IL-17 and IL-1β, and attenuated the migration capability of HCC cells. Herein, circUBAP2 counteracted miR-4756-mediated inhibition on IFIT1/3 via sponging miR-4756. miR-4756 inhibition reversed the effects induced by circUBAP2 silencing on the IL-17 and IL-1β levels and HCC cell migration. In orthotopic models, miR-4756 inhibition also reversed the effects on metastatic progression induced by silencing circUBAP2.
The ubiquitin ligase Peli1 inhibits ICOS and thereby Tfh-mediated immunity
Authors: Huang Xinfang , Hao Shumeng , Liu Junli , Huang Yuanyuan , Liu Manman , Xiao Chunyuan , Wang Yan , Pei Siyu , Yu Tao , Xu Jing , Wang Haikun , Dai Dongfang , Su Xiao , Xiao Yichuan 
Published: March 2021

AbstractT follicular helper (Tfh) cells are crucial for regulating autoimmune inflammation and protective immunity against viral infection. However, the molecular mechanism controlling Tfh cell differentiation is poorly understood. Here, through two mixed bone marrow chimeric experiments, we identified Peli1, a T cell-enriched E3 ubiquitin ligase, as an intrinsic regulator that inhibits Tfh cell differentiation. Peli1 deficiency significantly promoted c-Rel-mediated inducible T-cell costimulator (ICOS) expression, and PELI1 mRNA expression was negatively associated with ICOS expression on human CD4+ T cells. Mechanistically, increased ICOS expression on Peli1-KO CD4+ T cells enhanced the activation of PI3K-AKT signaling and thus suppressed the expression of Klf2, a transcription factor that inhibits Tfh differentiation. Therefore, reconstitution of Klf2 abolished the differences in Tfh differentiation and germinal center reaction between WT and Peli1-KO cells. As a consequence, Peli1-deficient CD4+ T cells promoted lupus-like autoimmunity but protected against H1N1 influenza virus infection in mouse models. Collectively, our findings established Peli1 as a critical negative regulator of Tfh differentiation and indicated that targeting Peli1 may have beneficial therapeutic effects in Tfh-related autoimmunity or infectious diseases.
Allele frequency of variants reported to cause adenine phosphoribosyltransferase deficiency
Authors: Runolfsdottir Hrafnhildur L. , Sayer John A. , Indridason Olafur S. , Edvardsson Vidar O. , Jensson Brynjar O. , Arnadottir Gudny A. , Gudjonsson Sigurjon A. , Fridriksdottir Run , Katrinardottir Hildigunnur , Gudbjartsson Daniel , Thorsteinsdottir Unnur , Sulem Patrick , Stefansson Kari , Palsson Runolfur 
Published: March 2021

AbstractAdenine phosphoribosyltransferase deficiency is a rare, autosomal recessive disorder of purine metabolism that causes nephrolithiasis and progressive chronic kidney disease. The small number of reported cases indicates an extremely low prevalence, although it has been suggested that missed diagnoses may play a role. We assessed the prevalence of APRT deficiency based on the frequency of causally-related APRT sequence variants in a diverse set of large genomic databases. A thorough search was carried out for all APRT variants that have been confirmed as pathogenic under recessive mode of inheritance, and the frequency of the identified variants examined in six population genomic databases: the deCODE genetics database, the UK Biobank, the 100,000 Genomes Project, the Genome Aggregation Database, the Human Genetic Variation Database and the Korean Variant Archive. The estimated frequency of homozygous genotypes was calculated using the Hardy-Weinberg equation. Sixty-two pathogenic APRT variants were identified, including six novel variants. Most common were the missense variants c.407T>C (p.(Met136Thr)) in Japan and c.194A>T (p.(Asp65Val)) in Iceland, as well as the splice-site variant c.400 + 2dup (p.(Ala108Glufs*3)) in the European population. Twenty-nine variants were detected in at least one of the six genomic databases. The highest cumulative minor allele frequency (cMAF) of pathogenic variants outside of Japan and Iceland was observed in the Irish population (0.2%), though no APRT deficiency cases have been reported in Ireland. The large number of cases in Japan and Iceland is consistent with a founder effect in these populations. There is no evidence for widespread underdiagnosis based on the current analysis.
A source of isotopically light organic carbon in a low-pH anoxic marine zone
Authors: Vargas Cristian A. , Cantarero Sebastian I. , Sepúlveda Julio , Galán Alexander , De Pol-Holz Ricardo , Walker Brett , Schneider Wolfgang , Farías Laura , D’Ottone Marcela Cornejo , Walker Jennifer , Xu Xiaomei , Salisbury Joe 
Published: March 2021

AbstractGeochemical and stable isotope measurements in the anoxic marine zone (AMZ) off northern Chile during periods of contrasting oceanographic conditions indicate that microbial processes mediating sulfur and nitrogen cycling exert a significant control on the carbonate chemistry (pH, AT, DIC and pCO2) of this region. Here we show that in 2015, a large isotopic fractionation between DIC and POC, a DIC and N deficit in AMZ waters indicate the predominance of in situ dark carbon fixation by sulfur-driven autotrophic denitrification in addition to anammox. In 2018, however, the fractionation between DIC and POC was significantly lower, while the total alkalinity increased in the low-pH AMZ core, suggesting a predominance of heterotrophic processes. An isotope mass-balance model demonstrates that variations in the rates of sulfur- and nitrogen-mediated carbon fixation in AMZ waters contribute ~7–35% of the POC exported to deeper waters. Thus, dark carbon fixation should be included in assessments of future changes in carbon cycling and carbonate chemistry due to AMZ expansion.