bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seismic and Electrical Geophysical Characterization of an Incipient Coastal Open‐System Pingo: Lagoon Pingo, Svalbard
Authors: Hammock Craig P. , Kulessa Bernd , Hiemstra John F. , Hodson Andrew J. , Hubbard Alun 
Published: December 2021

AbstractWhilst there has been a recent appreciation for the role of open‐system pingos in providing a fluid‐flow conduit through continuous permafrost that enables methane release, the formation and internal structure of these ubiquitous permafrost‐diagnostic landforms remains unclear. Here, we combine active‐source seismic measurements with electrical resistivity tomography to investigate the structural and subsurface characteristics of an incipient open‐system pingo actively emitting methane within the glacio‐isostatically uplifting fjord valley of Adventdalen, Svalbard. Wavefront inversion of seismic refractions delineate a spatially heterogeneous active layer, whilst deeper reflections identify the lithological boundaries between marine sediments and underlying shales at ∼68 m depth (p‐wave velocity of ∼1,790 ms−1). Low geometric mean inverted resistivities of 40–150 Ωm highlight the dominance of saline permafrost, whilst elevated resistivities (∼2 kΩm) occur close to the groundwater spring and in heaved areas around the pingo. Based on our results, we speculate that segregation ice dominates the pingo structure, given the absence of a notable resistivity contrast characteristic of injection ice that is typically expected within early open‐system pingo formation, and provides the most plausible geomorphic agent within the local fine‐grained sedimentology. Our results thereby indicate that sediment grain size and moisture availability can provide important controls on pingo formation. This study shows that open‐system pingos in coastal, saline permafrost environments may form differently, with implications for localized permafrost structure, its permeability to underlying gas reservoirs and consequent methane release.
A New Tectonic Model Between the Madagascar Ridge and Del Cano Rise in the Indian Ocean
Authors: Sato Taichi , Nogi Yoshifumi , Sato Hiroshi , Fujii Masakazu 
Published: December 2021

AbstractThe southern Indian Ocean has several prominent aseismic ridges recognized as oceanic large igneous provinces (i.e., the Madagascar Ridge, Del Cano Rise, Crozet Plateau, and Conrad Rise) in the off‐axis areas of the Southwest Indian Ridge (SWIR). However, previously obtained magnetic survey lines are sparse and not correctly aligned with the seafloor spreading direction; thus, the detailed spreading history, including the formation of these aseismic ridges, remains an open question. We reconstructed the tectonic history of two segments between the Discovery II and Gallieni fracture zones in the SWIR using newly obtained magnetic data (total and vector magnetic field) and an open‐source magnetic data set. We revealed that the southern Madagascar Ridge and the Del Cano Rise once formed a single bathymetric high and separated by at least Chron 30y, which is quite different from the global age model. In addition, the rises may have formed before Chron 34y, assuming an extinct ridge south of the Del Cano Rise. The two rises have been recognized as having formed by Marion hotspot plume‐induced excess volcanism around the active spreading ridge of the SWIR, which can explain locally isostatically compensated thicker‐than‐normal crust. However, linear magnetic anomalies have not been observed across the main part of these rises, suggesting that magmatic activity controlled by seafloor spreading is unlikely. Like other aseismic ridges in the southern Indian Ocean, these two rises may possibly have been formed partly by continental fragments rather than plume‐induced excess volcanism.
On the Origin of Seismic Anisotropy in the Shallow Crust of the Northern Volcanic Zone, Iceland
Authors: Bacon C. A. , Johnson J. H. , White R. S. , Rawlinson N. 
Published: December 2021

AbstractThe Icelandic crust is a product of its unique tectonic setting, where the interaction of an ascending mantle plume and the Mid‐Atlantic Ridge has caused elevated mantle melting, with the melt accreted and cooled in the crust to form an oceanic plateau. We investigate the strength and orientation of seismic anisotropy in the upper crust of the Northern Volcanic Zone using local earthquake shear‐wave splitting, with a view to understanding how the contemporary stress field may influence sub‐wavelength structure and processes. This is achieved using a data set comprising 50,000 earthquakes located in the top 10 km of the crust, recorded by up to 70 stations over a 9 year period. We find that anisotropy is largely confined to the top 3–4 km of the crust, with an average delay time of 0.10 ± 0.05 s, and an average orientation of the fast axis of anisotropy of N014°E ± 27°, which is perpendicular to the spreading direction of the Eurasian and North American plates (N106°E). These results are consistent with the presence of rift‐parallel cracks that gradually close with depth, the preferential opening of which is controlled by the regional stress field. Lateral variations in the strength of shear wave anisotropy (SWA) reveal that regions with the highest concentrations of earthquakes have the highest SWA values (∼10%), which reflects the presence of significant brittle deformation. Disruption of the orientation of the fast axis of anisotropy around Askja volcano can be related to local stress changes caused by underlying magmatic processes.
A Reference Section Through Fast‐Spread Lower Oceanic Crust, Wadi Gideah, Samail Ophiolite (Sultanate of Oman): Petrography and Petrology
Authors: Koepke J. , Garbe‐Schönberg D. , Müller T. , Mock D. , Müller S. , Nasir S. 
Published: December 2021

AbstractIn the absence of a complete profile through fast‐spreading modern oceanic crust, we established a reference profile through the whole paleo crust of the Samail ophiolite (Sultanate of Oman), which is regarded as the best analogue for fast‐spreading oceanic crust on land. To establish a coherent data set, we sampled the Wadi Gideah in the Wadi‐Tayin massif from the mantle section up to the sheeted dikes and performed different analytical and structural investigations on the same suite of samples. This paper reports our studies of the lower crust, a 5 km thick pile of gabbros, focusing on petrographic features and on the results of mineral analyses. Depth profiles of mineral compositions combined with petrological modeling reveal insights into the mode of magmatic formation of fast‐spreading lower oceanic crust, implying a hybrid accretion mechanism. The lower two thirds of the crust, mainly consisting of layered gabbros, formed via the injection of melt sills and in situ crystallization. Here, upward moving fractionated melts mixed with more primitive melts through melt replenishments, resulting in a slight but distinct upward differentiation trend. The upper third of the gabbroic crust is significantly more differentiated, in accord with a model of downward differentiation of a primitive parental melt originated from the axial melt lens located at the top of the gabbroic crust. Our hybrid model for crustal accretion requires a system to cool the deep crust, which was established by hydrothermal fault zones, initially formed on‐axis at very high temperatures.
A High‐Resolution Whole‐Atmosphere Model With Resolved Gravity Waves and Specified Large‐Scale Dynamics in the Troposphere and Stratosphere
Authors: Becker Erich , Vadas Sharon L. , Bossert Katrina , Harvey V. Lynn , Zülicke Christoph , Hoffmann Lars 
Published: December 2021

AbstractWe present a new version of the HIgh Altitude Mechanistic general Circulation Model (HIAMCM) with specified dynamics. We utilize a spectral method that nudges only the large‐scale flow to MERRA‐2 reanalysis. The nudged HIAMCM simulates gravity waves (GWs) down to horizontal wavelengths of about 200 km from the troposphere to the thermosphere like the free‐running model, including the generation of secondary and tertiary GWs. Case studies show that the simulated large‐scale GWs are consistent with those in the reanalysis, while the medium‐scale GWs compare well with observations in the northern winter 2016 stratosphere from the Atmospheric InfraRed Sounder (AIRS). GWs having wavelengths larger than about 1,350 km can be described with the nonlinear balance equation. The GWs relevant in the stratosphere, however, have smaller scales and require a different approach. We propose that the GW amplification due to kinetic energy transfer from the large‐scale flow combined with GW potential energy flux convergence helps to identify the mesoscale GW sources due to spontaneous emission. The GW amplification is strongest in the region of maximum large‐scale vertical wind shear in the mid‐stratosphere. Maps of the time‐averaged stratospheric GW activity simulated by the HIAMCM and computed from AIRS satellite data show a persistent hot spot over Europe during January 2016. At about 40 km, the average GW amplitudes are maximum in the region of fastest large‐scale flow. We argue that refraction of GWs originating in the troposphere, as well as GWs from spontaneous emission in the stratosphere contribute to this effect.
Increases in Future AR Count and Size: Overview of the ARTMIP Tier 2 CMIP5/6 Experiment
Authors: O’Brien T. A. , Wehner M. F. , Payne A. E. , Shields C. A. , Rutz J. J. , Leung L.‐R. , Ralph F. M. , Collow A. , Gorodetskaya I. , Guan B. , Lora J. M. , McClenny E. , Nardi K. M. , Ramos A. M. , Tomé R. , Sarangi C. , Shearer E. J. , Ullrich P. A. , Zarzycki C. , Loring B. , Huang H. , Inda‐Díaz H. A. , Rhoades A. M. , Zhou Y. 
Published: December 2021

AbstractThe Atmospheric River (AR) Tracking Method Intercomparison Project (ARTMIP) is a community effort to systematically assess how the uncertainties from AR detectors (ARDTs) impact our scientific understanding of ARs. This study describes the ARTMIP Tier 2 experimental design and initial results using the Coupled Model Intercomparison Project (CMIP) Phases 5 and 6 multi‐model ensembles. We show that AR statistics from a given ARDT in CMIP5/6 historical simulations compare remarkably well with the MERRA‐2 reanalysis. In CMIP5/6 future simulations, most ARDTs project a global increase in AR frequency, counts, and sizes, especially along the western coastlines of the Pacific and Atlantic oceans. We find that the choice of ARDT is the dominant contributor to the uncertainty in projected AR frequency when compared with model choice. These results imply that new projects investigating future changes in ARs should explicitly consider ARDT uncertainty as a core part of the experimental design.
Spatial and Temporal Variations of Incision Rate of the Middle Yellow River and Its Tributaries
Authors: Zhong Yuezhi , Willett Sean D. , Picotti Vincenzo , Xiong Jianguo , Zhang Huiping 
Published: December 2021

AbstractWe present a model to reconstruct spatiotemporal variation of uplift along the Jinshan Gorge of the Yellow River of Northern China based on quantitative analysis of the river channel profiles. We focus on the tributaries along the gorge that drain from the Loess Plateau on the Ordos crustal block. Base level fall on a tributary is genetically related to its trunk channel incision through the incision rate of the confluence point. We leverage this relationship to reconstruct a scaled incision history at each confluence point from an inversion analysis of tributary networks governed by the stream power law. In this way, we create an artificial geomorphic marker, that we refer to as a “pseudo‐terrace.” These metrics provide information on the incision history of the Yellow River. Our result shows a recent acceleration of river incision along the southern Jinshan Gorge, including spatial variations indicative of tectonic activity. The northern gorge exhibits more uniform and steady incision rates. This pattern can be attributed to on‐going lithospheric mantle upwelling beneath the southern Ordos Block.
Radar Derived Subglacial Properties and Landforms Beneath Rutford Ice Stream, West Antarctica
Authors: Schlegel Rebecca , Murray Tavi , Smith Andrew M. , Brisbourne Alex M. , Booth Adam D. , King Edward C. , Clark Roger A. 
Published: December 2021

AbstractBasal properties beneath ice streams and glaciers are known to be a control for ice flow dynamics, hence knowledge of them is crucial for predicting sea level due to changes in glacial dynamics. Basal properties, processes and topography also drive the formation of subglacial landforms. Bed properties beneath Rutford Ice Stream (West Antarctica) have previously been described using seismic acoustic impedance measurements at a sparse spatial coverage. Here, we derive bed properties in a 15 × 17 km grid of surface radar data with coverage and sampling much higher than previous seismic studies. Bed reflection amplitudes in surface radar data were calibrated using sediment porosities (ranging from 0.4–0.5) derived from seismic acoustic impedance. We find the bed properties are spatially variable, consisting of low porosity material in some areas and soft sediment in other areas. Comparison of seismic and surface radar data imply the low porosity material to be a consolidated sediment or sedimentary rock. Mega‐scale glacial lineations (MSGLs) are ubiquitous on the bed and consist of soft, high porosity, probably deforming sediment, consistent with previous interpretations of MSGLs. We find some MSGLs have high reflectivity on their crest, interpreted as water bodies overlying high porosity sediment, whereas the trough around and the upstream end of some landforms consist of low porosity material. Integrating these different observations, we place constraints on possible explanations for the occurrence of water on the crest of landforms.
Riparian Cottonwood Trees and Adjacent River Sediments Have Different Microbial Communities and Produce Methane With Contrasting Carbon Isotope Compositions
Authors: Smits Kristian M. , Grant Daniel S. , Johnston Sara Ellen , Bogard Matthew J. , Rood Stewart B. , Selinger L. Brent , Flanagan Lawrence B. 
Published: December 2021

AbstractRivers and their adjacent riparian forests are intimately linked by the exchange of water, nutrients, and organic matter. Both riparian cottonwood trees and adjacent river sediments host microbial communities including archeal methanogens, supporting methane production and emission to the atmosphere. Here we combine microbial community and in vitro stable isotope analyses to characterize the drivers of methane cycling in distinct anoxic habitats (river sediments vs. riparian cottonwood stems) associated with the Oldman River, southern Alberta (Canada). We demonstrate that, differences in the chemical characteristics of organic matter support divergent microbial communities that generate methane from distinct metabolic pathways. Organic matter in river sediments had C/N ratios approximately 50‐fold lower than in tree stems and had more diverse dissolved organic components. Contrasting substrate availability between river sediment and tree stems was likely the primary mechanism for the greater microbial diversity in river sediments than in tree stems, the significantly different bacterial communities, and the trend toward differing abundance of methanogen orders. The methane carbon isotope composition (δ13C values) differed for the tree stem (−103.6‰ to −70.6‰) and river sediment (−55.1‰ to −48.4‰) environments, suggesting that methane was primarily produced via CO2‐reduction in tree stems by Methanobacteriales, while river sediments produced more methane through acetate fermentation primarily by Methanosarcinales. This study demonstrates the importance of organic matter quality and microbial community composition in driving metabolic processes contributing to methane production and emission in rivers and adjacent riparian forests.
Elimination of negative feedback in TLR signalling allows rapid and hypersensitive detection of microbial contaminants
Authors: Seumen Clovis H. T. , Tomasiunaite Urte , Legler Daniel F. , Hauck Christof R. 
Published: December 2021

AbstractThe exquisite specificity of Toll-like receptors (TLRs) to sense microbial molecular signatures is used as a powerful tool to pinpoint microbial contaminants. Various cellular systems, from native human blood cells to transfected cell lines exploit TLRs as pyrogen detectors in biological preparations. However, slow cellular responses and limited sensitivity have hampered the replacement of animal-based tests such as the rabbit pyrogen test or lipopolysaccharide detection by Limulus amoebocyte lysate. Here, we report a novel human cell-based approach to boost detection of microbial contaminants by TLR-expressing cells. By genetic and pharmacologic elimination of negative control circuits, TLR-initiated cellular responses to bacterial molecular patterns were accelerated and significantly elevated. Combining depletion of protein phosphatase PP2ACA and pharmacological inhibition of PP1 in the optimized reporter cells further enhanced the sensitivity to allow detection of bacterial lipoprotein at 30 picogram/ml. Such next-generation cellular monitoring is poised to replace animal-based testing for microbial contaminants.
In-situ detoxification of schedule-I chemical warfare agents utilizing Zr(OH)4@W-ACF functional material for the development of next generation NBC protective gears
Authors: Imran Mohammad , Singh Virendra V. , Garg Prabhat , Mazumder Avik , Pandey Lokesh K. , Sharma Pushpendra K. , Acharya Jyotiranjan , Ganesan Kumaran 
Published: December 2021

AbstractChemical warfare agents (CWAs) have become a pivotal concern for the global community and spurred a wide spectrum of research for the development of new generation protective materials. Herein, a highly effective self-detoxifying filter consisting of in-situ immobilized Zirconium hydroxide [Zr(OH)4] over woven activated carbon fabric [Zr(OH)4@W-ACF] is presented for the removal of CWAs. It was prepared to harness the synergistic effect of high surface area of W-ACF, leads to high dispersion of CWAs and high phosphilicity and reactivity of [Zr(OH)4]. The synthesized materials were characterized by ATR-FTIR, EDX, SEM, TEM, XPS, TGA, and BET surface area analyzer. The kinetics of in-situ degradation of CWAs over Zr(OH)4@W-ACF were studied and found to be following the first-order reaction kinetics. The rate constant was found to be 0.244 min−1 and 2.31 × 10−2 min−1 for sarin and soman, respectively over Zr(OH)4@W-ACF. The potential practical applicability of this work was established by fabricating Zr(OH)4@W-ACF as reactive adsorbent layer for protective suit, and found to be meeting the specified criteria in terms of air permeability, tearing strength and nerve agent permeation as per TOP-08-2-501A:2013 and IS-17380:2020. The degradation products of CWAs were analyzed with NMR and GC–MS. The combined properties of dual functional textile with reactive material are expected to open up new exciting avenues in the field of CWAs protective clothing and thus find diverse application in defence and environmental sector.
Provocation of dry eye disease symptoms during COVID-19 lockdown
Authors: Neti Nutnicha , Prabhasawat Pinnita , Chirapapaisan Chareenun , Ngowyutagon Panotsom 
Published: December 2021

AbstractTo assess the impact of COVID-19 lockdown measures on dry-eye symptoms in a community-based population, a cross-sectional study was conducted during the first wave of the COVID-19 outbreak in Thailand. An online survey was distributed via social media between June and July 2020. The questionnaire elicited information on demographics, dry-eye symptoms, use of visual display terminals, and mental health status. There were 535 respondents. Thirty-seven percent reported having been diagnosed with dry-eye disease (DED). During the lockdown, the mean dry-eye symptom score (DESS) of overall participants dropped significantly from 81.6 ± 15.9 to 79.8 ± 17.4 (P < 0.001). The mean, daily, visual display terminal (VDT) usage increased from 10.55 ± 5.16 to 13.08 ± 5.65 h (P < 0.001). A negative correlation between age and VDT usage was observed in both the normal and lockdown situations. One-quarter of all participants had an abnormal mental health status. The female gender (OR 1.86; 95% CI 1.14–3.04) and increased VDT usage during the lockdown (OR 5.68; 95% CI 3.49–9.23) were independently associated with worsening dry-eye symptoms. The lockdown measures abruptly altered the behaviors and lifestyles of the overall population. Excessive exposure to VDTs were associated with deteriorated dry-eye symptoms, and it possibly contributed to the increased DED incidence in the surveyed population.
Development of a prediction score for in-hospital mortality in COVID-19 patients with acute kidney injury: a machine learning approach
Authors: Ponce Daniela , de Andrade Luís Gustavo Modelli , Claure-Del Granado Rolando , Ferreiro-Fuentes Alejandro , Lombardi Raul 
Published: December 2021

AbstractAcute kidney injury (AKI) is frequently associated with COVID-19 and it is considered an indicator of disease severity. This study aimed to develop a prognostic score for predicting in-hospital mortality in COVID-19 patients with AKI (AKI-COV score). This was a cross-sectional multicentre prospective cohort study in the Latin America AKI COVID-19 Registry. A total of 870 COVID-19 patients with AKI defined according to the KDIGO were included between 1 May 2020 and 31 December 2020. We evaluated four categories of predictor variables that were available at the time of the diagnosis of AKI: (1) demographic data; (2) comorbidities and conditions at admission; (3) laboratory exams within 24 h; and (4) characteristics and causes of AKI. We used a machine learning approach to fit models in the training set using tenfold cross-validation and validated the accuracy using the area under the receiver operating characteristic curve (AUC-ROC). The coefficients of the best model (Elastic Net) were used to build the predictive AKI-COV score. The AKI-COV score had an AUC-ROC of 0.823 (95% CI 0.761–0.885) in the validation cohort. The use of the AKI-COV score may assist healthcare workers in identifying hospitalized COVID-19 patients with AKI that may require more intensive monitoring and can be used for resource allocation.
CD105+CD90+CD13+ identifies a clonogenic subset of adventitial lung fibroblasts
Authors: Kadefors Måns , Rolandsson Enes Sara , Åhrman Emma , Michaliková Barbora , Löfdahl Anna , Dellgren Göran , Scheding Stefan , Westergren-Thorsson Gunilla 
Published: December 2021

AbstractMesenchymal cells are important components of specified niches in the lung, and can mediate a wide range of processes including tissue regeneration and repair. Dysregulation of these processes can lead to improper remodeling of tissue as observed in several lung diseases. The mesenchymal cells responsible remain poorly described, partially due to the heterogenic nature of the mesenchymal compartment and the absence of appropriate markers. Here, we describe that CD105+CD90+ mesenchymal cells can be divided into two populations based on their expression of CD13/aminopeptidase N (CD105+CD90+CD13− and CD105+CD90+CD13+). By prospective isolation using FACS, we show that both these populations give rise to clonogenic fibroblast-like cells, but with an increased clonogenic and proliferative capacity of CD105+CD90+CD13+ cells. Transcriptomic and spatial analysis pinpoints an adventitial fibroblast subset as the origin of CD105+CD90+CD13+ clonogenic mesenchymal cells in human lung.