bluuebunny/crossref_metadata_2025_split huggingface dataset:
Was Gale Crater (Mars) Connected to a Regionally Extensive Groundwater System?
Authors: Roseborough V. , Horvath D. G. , Palucis M. C. 
Published: March 2021

AbstractGale crater, home of the Curiosity rover, contains some of the best geomorphic and sedimentologic evidence on Mars for large lakes during the Hesperian and Amazonian. Orbital data and rover observations of delta deposits and terminations of gully networks suggest several phases of stable lake levels. However, the regional extent, water source (groundwater vs. surface water), and climate during each lake stand are debated. Consistent gully network termination elevations (GNTEs) within Gale and 17 regional craters suggest that GNTEs record paleolake levels. Hydrologic modeling indicates these lakes may have been coeval and the result of a regional groundwater table, recording a drying trend from subhumid conditions to semiarid conditions. Crater counting indicates that most lake‐hosting craters impacted after ∼3.7 Ga and surface water persisted intermittently until the Early Amazonian, constraining the timing but not duration of lakes. This work has implications for understanding water sources and volumes affecting sediments investigated by Curiosity.
How Does the North Atlantic SST Pattern Respond to Anthropogenic Aerosols in the 1970s and 2000s?
Authors: Fiedler S. , Putrasahan D. 
Published: March 2021

AbstractWe show how changes in the global distribution of anthropogenic aerosols favor different spatial patterns in the North Atlantic sea‐surface temperature (NASST). The NASSTs largely show the expected decrease associated with the anthropogenic aerosols in the 1970s, but also an unusual warming response in the eastern sub‐polar gyre, the region of the North Atlantic warming hole. The NASST response reversed for the anthropogenic aerosols in the 2000s against 1970s. The regional reduction in anthropogenic aerosols favored as follows: (1) a strengthening of the warming hole and (2) a NASST increase at high latitudes associated with changes in the coupled atmosphere‐ocean dynamics. We found that the gyre component of the northward Atlantic heat transport in mid‐to high latitudes is an important driver for the heat convergence associated with the NASST patterns. At least two‐thirds of the NASST response in MPI‐ESM1.2 is associated with aerosol‐cloud interactions, highlighting the need to better understand them.
Globally Correlated Ground Magnetic Disturbances During Substorms
Authors: Ohtani Shinichi , Imajo Shun , Nakamizo Aoi , Gjerloev Jesper W. 
Published: March 2021

AbstractWe observationally address substorm‐related ground magnetic disturbances in terms of the substorm current wedge (SCW) system. The study consists of three data analyses, which approach different aspects of this subject. First, by comparing nightside magnetic disturbances below and above the ionosphere, we confirm that substorm‐related midlatitude magnetic disturbances around the edges of the SCW can be attributed to a remote current system (i.e., SCW) rather than to a local ionospheric current. Second, we statistically examine the magnetic local time (MLT) distributions of the correlation between midlatitude magnetic variations and the nightside westward auroral electrojet (AEJ). We confirm that nightside magnetic disturbances are consistent with the SCW, and find that correlated magnetic variations extend to the midday sector. Finally, we introduce midlatitude and high‐latitude geomagnetic indices for each MLT quadrant, and find that their variations are often correlated with the nightside AEJ intensity. From the magnitude of the correlated variations it is inferred that midday magnetic disturbances at both midlatitudes and high latitudes are remote effects of the SCW. In the dawn‐sector and dusk‐sector auroral zone, in contrast, correlated magnetic disturbances can be attributed mostly to the global enhancement of AEJs, which suggests that the global region‐1 system also changes in correlation with the nightside westward AEJ during substorms. These results consistently indicate that ground magnetic disturbances are correlated globally with the substorm westward AEJ. In contrast, the geomagnetic effect of midlatitude ionospheric currents must be relatively small not only on the night side but also on the day side.
Potassium Isotope Fractionation During Magmatic Differentiation and the Composition of the Mantle
Authors: Hu Yan , Teng Fang‐Zhen , Helz Rosalind T. , Chauvel Catherine 
Published: March 2021

AbstractStable potassium (K) isotopes are emerging as tracers of terrestrial recycling and planetary processes. These applications require well‐defined K isotopic compositions for the mantle and the bulk silicate Earth (BSE). Both values are determined primarily by basalts formed via partial melting of the mantle. Basaltic melts experience igneous differentiation before reaching the surface, which may alter their isotopic compositions compared to their mantle sources. This study investigates K isotope fractionation during the differentiation and solidification of the Kilauea Iki lava lake, Hawaii, for which crystallization and thermal histories are well documented. High‐precision K isotopic ratios (δ41K) are measured in 13 Kilauea Iki samples that cover its complete differentiation history, ranging from olivine‐rich, high‐MgO cumulates to increasingly differentiated, MgO‐depleted samples. The limited δ41K range of −0.42 to −0.37‰ in all but one sample reveals no analytically resolvable fractionation across diverse bulk compositions, even though their bulk MgO contents varied from 26.9 to 2.37 wt.%. The lack of K isotopic fractionation is consistent with an absence of K‐rich minerals in the crystallizing assemblage, where only plagioclase can accommodate a small amount of K. A highly differentiated vein displays the lowest δ41K of −0.47‰ among the Kilauea Iki suite, which is consistent with our modeling calculations that suggest measurable K isotope fractionation at more advanced magmatic differentiation stages. Combining our new results with literature data, we propose an average δ41K of −0.42 ± 0.08‰ (2SD) for the pristine mantle and of −0.42 ± 0.07‰ (2SD) for the BSE.
Enrichment of Trace Metals (V, Cu, Co, Ni, and Mo) in Arctic Sediments—From Siberian Arctic Shelves to the Basin
Authors: Li Li , Wang Xiaojing , Ren Yijun , Su Huaqiang , Hu Limin , Yang Gang , Li Zhongqiao , Bosin Aleksandr A. , Astakhov Anatolii S. , Chen Jianfang , Liu Yanguang , Shi Xuefa 
Published: March 2021

AbstractWith 50% of the Arctic Ocean is consisted of continental shelves, extensive shelf‐basin exchange processes exist here and plays a key role in regulating the biogeochemical recycling process of trace metals in the Arctic region. In this study, short sediment cores were collected along three transects from Siberian‐Chukchi shelves to adjacent slope/basin areas. An increasing trend was found for the bulk concentrations of several metals (V, Cu, Co, Ni, and Mo) from shelf to slope/basin cores with increasing water depth. Sequential extraction experiments indicated that the Fe/Mn oxide fractions increased significantly from shelf (9%–21%) to basin cores (24%–76%) for Cu, Co, Ni, and V, while the organic/sulfide phase remained significant (∼40%) for Mo. In addition, the observed dissolved metal concentrations in porewater indicated the remobilization of Fe, Mn, and Mo from shelf sediment, while V was always removed from water to the sediment, both on the shelf or in the slope/basin. Overall, in combination with the statistical analysis, we proposed that metals are transported from shelves to the central Arctic and are scavenged mainly by Mn oxides from the water column, which results in the enrichment of metals in slope/basin sediment. With the climate change, such transport and accumulation mechanism may be intensified over time, slowly leading the Arctic sediment to be a more and more important sink for those metals.
Estimating the Impacts of Radiation Belt Electrons on Atmospheric Chemistry Using FIREBIRD II and Van Allen Probes Observations
Authors: Duderstadt K. A. , Huang C.‐L. , Spence H. E. , Smith S. , Blake J. B. , Crew A. B. , Johnson A. T. , Klumpar D. M. , Marsh D. R. , Sample J. G. , Shumko M. , Vitt F. M. 
Published: March 2021

AbstractThis study considers the impact of electron precipitation from Earth's radiation belts on atmospheric composition using observations from the NASA Van Allen Probes and NSF Focused Investigations of Relativistic Electron Burst Intensity, Range, and Dynamics (FIREBIRD II) CubeSats. Ratios of electron flux between the Van Allen Probes (in near‐equatorial orbit in the radiation belts) and FIREBIRD II (in polar low Earth orbit) during spacecraft conjunctions (2015–2017) allow an estimate of precipitation into the atmosphere. Total Radiation Belt Electron Content, calculated from Van Allen Probes RBSP‐ECT MagEIS data, identifies a sustained 10‐day electron loss event in March 2013 that serves as an initial case study. Atmospheric ionization profiles, calculated by integrating monoenergetic ionization rates across the precipitating electron flux spectrum, provide input to the NCAR Whole Atmosphere Community Climate Model in order to quantify enhancements of atmospheric HOx and NOx and subsequent destruction of O3 in the middle atmosphere. Results suggest that current APEEP parameterizations of radiation belt electrons used in Coupled Model Intercomparison Project may underestimate the duration of events as well as higher energy electron contributions to atmospheric ionization and modeled NOx concentrations in the mesosphere and upper stratosphere.
New Particle Formation and Growth to Climate‐Relevant Aerosols at a Background Remote Site in the Western Himalaya
Authors: Sebastian Mathew , Kanawade Vijay P. , Soni Vijay K. , Asmi Eija , Westervelt Daniel. M. , Vakkari Ville , Hyvärinen Antti‐Pekka , Pierce Jeffrey R. , Hooda Rakesh K. 
Published: March 2021

AbstractNew particle formation (NPF) can influence the Earth's radiative budget when the newly formed particles grow to climate‐relevant sizes. Here, we present analysis of 21 months of continuous aerosol size distribution measurements at a background remote site in the western Himalaya and provide observational evidence that newly formed particles grow to cloud condensation nuclei (CCN)‐active sizes (i.e., >20–100 nm in diameter). Out of total 55 NPF events, 38 (66%) events occurred in the pre‐monsoon season (March–May). NPF events were classified into those with and without pollution influence as polluted and cleaner, respectively, using black carbon data. The analysis of air mass age, based on the ratio of number concentration of Aitken to accumulation mode aerosols, indicated that NPF occurred in the relatively cleaner air masses reaching to the site. The median formation rate of 10 nm particles and particle growth rates for cleaner events were three‐fold and two‐fold, respectively, higher than polluted events. We present the first estimates of the survival probability of newly formed particles to 50 and 100 nm size, which was not attempted in an Indian environment previously. The survival probability to 50 nm particles ranged from 44% to 98%, with a mean and standard deviation of 82 ± 18%. On average, ∼60% of the particles surviving to 50 nm survived to 100 nm, making the overall survival probability of 100 nm to 53 ± 31%. This indicates that the probability of nucleated particles growing to CCN‐active sizes under a large source of condensing vapor (transported from nearby lower‐altitude regions) and low pre‐existing particle concentrations (background mountain site) is high compared to the previous studies. These findings highlight the importance of the efficiency of nucleation events for producing CCN, which is a critical basis of aerosol indirect effects.
Modeling Ammonia and Its Uptake by Secondary Organic Aerosol Over China
Authors: Wu Kai , Zhu Shupeng , Liu Yiming , Wang Haolin , Yang Xianyu , Liu Lei , Dabdub Donald , Cappa Christopher D. 
Published: March 2021

AbstractAtmospheric ammonia (NH3) can affect nitrogen deposition, particle acidity, and gas‐particle partitioning. Although the inorganic chemistry of NH3 in fine particulate (PM2.5) formation are well‐constrained, the understanding of interactions between NH3 and secondary organic aerosol (SOA) are rather insufficient until recently. Laboratory studies indicate that NH3 molecule can react with SOA then forms nitrogen‐containing organic compounds (NOCs), which can further react to form heterocyclic organic compounds. In this study, we use a modified version of the CMAQ model to simulate the potential importance of the SOA‐ammonia uptake mechanism on air quality over China in summer and winter 2017, considering a range of assumed NH3 uptake coefficients (10−3–10−5). Our results show that uptake of NH3 by SOA leads to a decrease in gas‐phase NH3 mixing ratio, by as much as 27.5% and 19.0% for the highest uptake coefficient scenario (10−3) in summer and winter, respectively. The largest reduction of ammonia occurs over the Sichuan Basin and the North China Plain. The reduction of gas‐phase NH3 engenders a decrease of ammonium nitrate, by up to 30%, but has little impact on the ammonium sulfate concentration. Uptake of NH3 does not significantly affect SOA concentrations owing to overall moderate changes in aerosol acidity, and thus small effects on SOA formation from isoprene. Altogether, NH3 uptake led to a reduction in the average PM2.5 concentration up to 8.9% and 8.7% for the highest uptake coefficient (10−3) in summer and winter, respectively. These results highlight the need for better constraints on the NH3‐SOA interactions.
Application of Symmetric Instability Parameterization in the Coastal and Regional Ocean Community Model (CROCO)
Authors: Dong Jihai , Fox‐Kemper Baylor , Zhu Jinxuan , Dong Changming 
Published: March 2021

AbstractAs one kind of submesoscale instability, symmetric instability (SI) of the ocean surface mixed layer (SML) plays a significant role in modulating the SML energetics and material transport. The small spatial scales of SI, O(10 m–1 km), are not resolved by current climate ocean models and most regional models. This study describes comparisons in an idealized configuration of the SI parameterization scheme proposed by Bachman et al. (2017, https://doi.org/10.1016/j.ocemod.2016.12.003) (SI‐parameterized) versus the K‐Profile Parameterization scheme (SI‐neglected) as compared to a SI‐permitting model; all variants use the Coastal and Regional Ocean Community Model version of the Regional Ocean Modeling System and this study also serves to introduce the SI parameterization in that model. In both the SI‐parameterized and SI‐permitting models, the geostrophic shear production is enhanced and anticyclonic potential vorticity is reduced versus the SI‐neglected model. A comprehensive comparison of the energetics (geostrophic shear production, vertical buoyancy flux), mixed layer thickness, potential vorticity, and tracer redistribution indicate that all these variables in the SI‐parameterized case have structures closer to the SI‐permitting case in contrast to the SI‐neglected one, demonstrating that the SI scheme qualitatively improves representation of the impacts of SI. This work builds toward applying the SI scheme in a realistic regional or climate model.
Numerical Analysis of the Effect of Subgrid Variability in a Physically Based Hydrological Model on Runoff, Soil Moisture, and Slope Stability
Authors: Leonarduzzi E. , Maxwell R. M. , Mirus B. B. , Molnar P. 
Published: March 2021

AbstractIn coarse resolution hydrological modeling, we face the problem of subgrid variability, the effects of which are difficult to express and are often hidden in the parameterization and calibration. We present a numerical experiment with the physically based hydrological model ParFlow‐CLM with which we quantify the effect of subgrid heterogeneities in headwater catchments within the cell size typically used for regional hydrological applications. We simulate homogeneous domains and domains with subgrid heterogeneities in topography or soil thickness for two climates and soil types. The presence of side slope is the main error source, leading to large underestimation of runoff, and marginally also of evapotranspiration. The spatial distribution of soil saturation in the presence of subgrid variability in topography also leads to underestimation of landslide risk. Soil thickness is the second influential subgrid property, affecting soil moisture distribution and surface runoff formation. Results are consistent for the climates and the soil types considered. The topographic wetness index approach is tested as a way to downscale soil moisture simulations within the domain. Although this method is successful in reproducing some spatial variability and patterns, it fails when the coarse grid mean soil saturation is inaccurate or subgrid topography does not represent subsurface flow paths accurately. We conclude that ignoring subgrid variability in topography and soil thickness in coarse‐scale hydrological models may lead locally to underestimation of runoff and slope instability. Users of such models should be aware of these biases and consider ways to include subgrid effects in coarse‐scale hydrological predictions.
A Dynamic and Fully Implicit Non‐Isothermal, Two‐Phase, Two‐Component Pore‐Network Model Coupled to Single‐Phase Free Flow for the Pore‐Scale Description of Evaporation Processes
Authors: Weishaupt K. , Helmig R. 
Published: March 2021

AbstractWe couple a dynamic, fully implicit non‐isothermal two‐phase, two‐component pore‐network model (PNM) to a free‐flow domain where the single‐phase flow Navier‐Stokes equations with component and energy transport are solved. A monolithic coupling scheme guarantees the conservation of mass, momentum and energy across the coupling interface and allows solving the system without any coupling iterations. We present a numerical example and show that the model is able to temporally resolve the pore‐local flow and transport dynamics of an evaporation process.
Statistical Investigation of the Frequency Dependence of the Chorus Source Mechanism of Plasmaspheric Hiss
Authors: Meredith Nigel P. , Bortnik Jacob , Horne Richard B. , Li Wen , Shen Xiao‐Chen 
Published: March 2021

AbstractWe use data from eight satellites to statistically examine the role of chorus as a potential source of plasmaspheric hiss. We find that the strong equatorial (|λm| < 6°) chorus wave power in the frequency range 50 < f < 200 Hz does not extend to high latitudes in any magnetic local time sector and is unlikely to be the source of the low frequency plasmaspheric hiss in this frequency range. In contrast, strong equatorial chorus wave power in the medium frequency range 200 < f < 2,000 Hz is observed to extend to high latitudes and low altitudes in the pre‐noon sector, consistent with ray tracing modeling from a chorus source and supporting the chorus to hiss generation mechanism. At higher frequencies, chorus may contribute to the weak plasmaspheric hiss seen on the dayside in the frequency range 2,000 < f < 3,000 Hz band but is not responsible for the weak plasmaspheric hiss on the nightside in the frequency range 3,000 < f < 4,000 Hz.
Calcium channel α2δ1 subunit is a functional marker and therapeutic target for tumor-initiating cells in non-small cell lung cancer
Authors: Ma Yuanyuan , Yang Xiaodan , Zhao Wei , Yang Yue , Zhang Zhiqian 
Published: March 2021

AbstractIt is hypothesized that tumor-initiating cells (TICs) with stem cell-like properties constitute a sustaining force to drive tumor growth and renew fully established malignancy. However, the identification of such a population in non-small cell lung carcinoma (NSCLC) has been hindered by the lacking of reliable surface markers, and very few of the currently available surface markers are of functional significance. Here, we demonstrate that a subpopulation of TICs could be specifically defined by the voltage-gated calcium channel α2δ1 subunit from non-small cell lung carcinoma (NSCLC) cell lines and clinical specimens. The α2δ1+ NSCLC TICs are refractory to conventional chemotherapy, and own stem cell-like properties such as self-renewal, and the ability to generate heterogeneous tumors in NOD/SCID mice. Moreover, α2δ1+ NSCLC cells are more enriched for TICs than CD133+, or CD166+ cells. Interestingly, α2δ1 is functionally sufficient and indispensable to promote TIC properties by mediating Ca2+ influx into cells, which subsequently activate Calcineurin/NFATc2 signaling that directly activates the expression of NOTCH3, ABCG2. Importantly, a specific antibody against α2δ1 has remarkably therapeutic effects on NSCLC xenografts by eradicating TICs. Hence, targeting α2δ1 to prevent calcium influx provides a novel strategy for targeted therapy against TICs of NSCLC.
Association of sleep disorders with subfoveal choroidal thickness in preschool children
Authors: Shen Shiya , Li Xiaoxiao , Li Rui , Huang Dan , Zhao Xiaoyan , Zhang Xiaohan , Hao Qingfeng , Sun Qigang , Tong Haohai , Zheng Xinyu , Cao Yelongzi , Liu Shuning , Zhu Hui , Liu Hu 
Published: March 2021

Abstract
Objective
To explore the association between sleep disorders and subfoveal choroidal thickness (SFCT) in preschool children.

Methods
In this population-based cross-sectional study, children aged 60–72 months were measured for SFCT using spectral-domain optical coherence tomography (SD-OCT) and for sleep disorders using the Chinese version of Children’s Sleep Habits Questionnaire (CSHQ). Multiple linear regression analyses were performed to assess the association between sleep disorders and SFCT.

Results
A total of 1337 children (mean (SD) age: 66.88 (3.41) months) were included in the analyses. In multivariable linear analysis, a higher total CSHQ score (indicating higher likelihood of sleep disorders) was associated with a thinner subfoveal choroid (beta, −0.070; 95% CI, −0.141 to −0.001; P = 0.046). When each of eight CSHQ subscale scores was analysed by the multivariable model, only the Daytime Sleepiness subscale score was negatively associated with the SFCT (beta, −0.115; 95% CI, −0.183 to −0.046; P = 0.001). The children with clinically significant daytime sleepiness (n = 364, 27.2%) had significantly thinner subfoveal choroid than other children (295.47 vs. 308.52 μm, P = 0.007).

Conclusions
Only daytime sleepiness was significantly associated with SFCT in preschool children in this study. The potential relationship between sleep disorders during childhood and children’s ocular development needs further research.
Overcoming the design, build, test bottleneck for synthesis of nonrepetitive protein-RNA cassettes
Authors: Katz Noa , Tripto Eitamar , Granik Naor , Goldberg Sarah , Atar Orna , Yakhini Zohar , Orenstein Yaron , Amit Roee 
Published: March 2021

AbstractWe apply an oligo-library and machine learning-approach to characterize the sequence and structural determinants of binding of the phage coat proteins (CPs) of bacteriophages MS2 (MCP), PP7 (PCP), and Qβ (QCP) to RNA. Using the oligo library, we generate thousands of candidate binding sites for each CP, and screen for binding using a high-throughput dose-response Sort-seq assay (iSort-seq). We then apply a neural network to expand this space of binding sites, which allowed us to identify the critical structural and sequence features for binding of each CP. To verify our model and experimental findings, we design several non-repetitive binding site cassettes and validate their functionality in mammalian cells. We find that the binding of each CP to RNA is characterized by a unique space of sequence and structural determinants, thus providing a more complete description of CP-RNA interaction as compared with previous low-throughput findings. Finally, based on the binding spaces we demonstrate a computational tool for the successful design and rapid synthesis of functional non-repetitive binding-site cassettes.