bluuebunny/crossref_metadata_2025_split huggingface dataset:
Foreshock Ion Motion Across Discontinuities: Formation of Foreshock Transients
Authors: Liu Terry Z. , Angelopoulos Vassilis , Vu Andrew , Zhang Hui 
Published: April 2023

AbstractIn the ion foreshock, hot flow anomalies (HFAs) and foreshock bubbles (FBs) are two types of foreshock transients that have the strongest fluctuations, which can disturb the magnetosphere‐ionosphere system and increase shock acceleration efficiency. They form due to interaction between the foreshock ions and solar wind discontinuities: the direction of the foreshock ion‐driven current and whether it decreases or increases the magnetic field strength behind the discontinuity determine whether the transient's formation can be promoted or suppressed. Thus, to predict the HFA and FB formation and forecast their space weather effects, it is necessary to predict the foreshock ion‐driven current direction. In this study, we derive analytical equations of foreshock ion velocities within discontinuities to estimate foreshock ion‐driven current direction, which provides a quantitative criterion of HFA and FB formation. To validate the criterion, we use Acceleration Reconnection Turbulence & Electrodynamics of Moon's Interaction with the Sun to observe pristine solar wind discontinuities and calculate discontinuity parameters. We use Magnetospheric Multiscale to observe the foreshock ion motion around the discontinuities and show that the data support our model. This study is another step toward a predictive model of HFA and FB formation so that we can forecast their space weather effects at Earth using solar wind observations at lunar orbit or L1.
Wave Climate Variability and Trends in Tuvalu Based on a 44‐Year High‐Resolution Wave Hindcast
Authors: Wandres Moritz , Espejo Antonio , Damlamian Hervé 
Published: April 2023

AbstractWaves are one of the main causes of coastal flooding and shoreline change in low‐lying atoll nations like Tuvalu. A detailed understanding of Tuvalu’s wave climate is therefore critical for decision‐makers, coastal engineers, and disaster‐risk managers. Here, we investigate Tuvalu’s wind‐wave climate, changes due to large‐scale climate variability, and long‐term trends. A 44‐year (1979–2022) high‐resolution wave hindcast was developed using the unstructured version of the wave model Simulating Waves Nearshore (SWAN). The model resolution varied between 20 km offshore in deep water and 300 m close to shore. The model was forced with the European Centre for Medium‐Range Weather Forecasts Reanalysis v5 (ERA5) wind and boundary wave conditions. Northern and Southern Hemisphere winter months produced the largest and most powerful waves. Through the analysis of the directional wave energy spectra, we identified three main wave energy sources: (a) extratropical storms in the Southern Ocean; (b) extratropical storms in the North Pacific; and (c) easterly trade winds. Slightly positive trends in high‐frequency (∼10 s) wave energy from the east and low‐frequency (∼15 s) wave energy from the southwest were linked to an intensification of trade winds and an intensification and poleward displacement of the Southern Ocean storm belt over recent decades. The interannual variability of Tuvalu’s wave climate was strongly linked to large‐scale climate modes such as El Niño Southern Oscillation, Pacific Decadal Oscillation, and Arctic and Antarctic Oscillation. The study builds on previous research and significantly enhances the understanding of Tuvalu’s wave climate variability.
Thermospheric Temperature and Density Variability During 3–4 February 2022 Minor Geomagnetic Storm
Authors: Laskar F. I. , Sutton E. K. , Lin D. , Greer K. R. , Aryal S. , Cai X. , Pedatella N. M. , Eastes R. W. , Wang W. , Codrescu M. V. , McClintock W. E. 
Published: April 2023

AbstractThemospheric conditions during a minor geomagnetic event of 3 and 4 February 2022 has been investigated using disk temperature (Tdisk) observations from Global‐scale Observations of the Limb and Disk (GOLD) mission and model simulations. GOLD observed that the Tdisk increases by more than 60 K during the storm event when compared with pre‐storm quiet days. A comparison of the Tdisk with effective temperatures (Teff, i.e., a weighted average based on airglow emission layer) from Mass Spectrometer Incoherent Scatter radar version 2 (MSIS2) and Multiscale Atmosphere‐Geospace Environment (MAGE) models shows that MAGE outperforms MSIS2 during this particular event. MAGE underestimates the Teff by about 2%, whereas MSIS2 underestimates it by 7%. As temperature enhancements lead to an expansion of the thermosphere and resulting density changes, the value of the temperature enhancement observed by GOLD can be utilized to find a GOLD equivalent MSIS2 (GOLD‐MSIS) simulation—from a set of MSIS2 runs obtained by varying geomagnetic ap index values. From the MSIS‐GOLD run we found that the thermospheric density enhancement varies with altitude from 15% (at 150) to 80% (at 500 km). Independent simulations from the MAGE model also show a comparable enhancement in neutral density. These results suggest that even a modest storm could impact the thermospheric densities significantly and GOLD data can be used to improve the empirical and assimilative models of the thermosphere.
Non-Hermitian chiral degeneracy of gated graphene metasurfaces
Authors: Baek Soojeong , Park Sang Hyun , Oh Donghak , Lee Kanghee , Lee Sangha , Lim Hosub , Ha Taewoo , Park Hyun Sung , Zhang Shuang , Yang Lan , Min Bumki , Kim Teun-Teun 
Published: April 2023

AbstractNon-Hermitian degeneracies, also known as exceptional points (EPs), have been the focus of much attention due to their singular eigenvalue surface structure. Nevertheless, as pertaining to a non-Hermitian metasurface platform, the reduction of an eigenspace dimensionality at the EP has been investigated mostly in a passive repetitive manner. Here, we propose an electrical and spectral way of resolving chiral EPs and clarifying the consequences of chiral mode collapsing of a non-Hermitian gated graphene metasurface. More specifically, the measured non-Hermitian Jones matrix in parameter space enables the quantification of nonorthogonality of polarisation eigenstates and half-integer topological charges associated with a chiral EP. Interestingly, the output polarisation state can be made orthogonal to the coalesced polarisation eigenstate of the metasurface, revealing the missing dimension at the chiral EP. In addition, the maximal nonorthogonality at the chiral EP leads to a blocking of one of the cross-polarised transmission pathways and, consequently, the observation of enhanced asymmetric polarisation conversion. We anticipate that electrically controllable non-Hermitian metasurface platforms can serve as an interesting framework for the investigation of rich non-Hermitian polarisation dynamics around chiral EPs.
Tardigrade-inspired extremotolerant glycerogels
Authors: Mredha Md. Tariful Islam , Lee Yoonseong , Rama Varma Adith Varma , Gupta Tanish , Manimel Wadu Rumesh Rangana , Jeon Insu 
Published: April 2023

AbstractWe developed extremotolerant glycerogels (GGs) with well-modulated polymer structures, functions, and properties, inspired by the tun formation of tardigrades. GGs comprising extreme protected intra- and intermolecular networks are obtained through a very slow structure building process, which includes the smooth replacement of water in predesigned hydrogels with glycerol and thermal annealing while retaining the structures and functions of the original hydrogels. Four different GGs are fabricated as proofs-of-concept using different crosslinkers and polymers. Although various polyol-based wide-temperature-tolerant gels fabricated by conventional methods fail to demonstrate stabilities at low and high temperature extremes simultaneously, the GGs fabricated by our bioinspired method exhibit long-term stability (approaching one month) over an extremely wide temperature range (−50–80 °C) and thermal-shock-absorption capabilities at 150 °C. Furthermore, our versatile method enables us to program GGs with wide ranges of stiffness, strength, stretchability, and toughness values and elasticity, plasticity, hysteresis, and self-recoverability capabilities. The self-weldability, electrical patternability, and applicability characteristics of the GGs as electrolytes and supercapacitors demonstrate their complex 3D designability and facile functionalization capability aspects. The various functional GGs developed through the proposed method are applicable for the design of diverse extremotolerant, flexible, and stretchable devices for biological, electrical/electronic, and soft robotics applications.
Distributed processing for value-based choice by prelimbic circuits targeting anterior-posterior dorsal striatal subregions in male mice
Authors: Choi Kyuhyun , Piasini Eugenio , Díaz-Hernández Edgar , Cifuentes Luigim Vargas , Henderson Nathan T. , Holly Elizabeth N. , Subramaniyan Manivannan , Gerfen Charles R. , Fuccillo Marc V. 
Published: April 2023

AbstractFronto-striatal circuits have been implicated in cognitive control of behavioral output for social and appetitive rewards. The functional diversity of prefrontal cortical populations is strongly dependent on their synaptic targets, with control of motor output mediated by connectivity to dorsal striatum. Despite evidence for functional diversity along the anterior-posterior striatal axis, it is unclear how distinct fronto-striatal sub-circuits support value-based choice. Here we found segregated prefrontal populations defined by anterior/posterior dorsomedial striatal target. During a feedback-based 2-alternative choice task, single-photon imaging revealed circuit-specific representations of task-relevant information with prelimbic neurons targeting anterior DMS (PL::A-DMS) robustly modulated during choices and negative outcomes, while prelimbic neurons targeting posterior DMS (PL::P-DMS) encoded internal representations of value and positive outcomes contingent on prior choice. Consistent with this distributed coding, optogenetic inhibition of PL::A-DMS circuits strongly impacted choice monitoring and responses to negative outcomes while inhibition of PL::P-DMS impaired task engagement and strategies following positive outcomes. Together our data uncover PL populations engaged in distributed processing for value-based choice.
Atomic-scale origin of the low grain-boundary resistance in perovskite solid electrolyte Li0.375Sr0.4375Ta0.75Zr0.25O3
Authors: Lee Tom , Qi Ji , Gadre Chaitanya A. , Huyan Huaixun , Ko Shu-Ting , Zuo Yunxing , Du Chaojie , Li Jie , Aoki Toshihiro , Wu Ruqian , Luo Jian , Ong Shyue Ping , Pan Xiaoqing 
Published: April 2023

AbstractOxide solid electrolytes (OSEs) have the potential to achieve improved safety and energy density for lithium-ion batteries, but their high grain-boundary (GB) resistance generally is a bottleneck. In the well-studied perovskite oxide solid electrolyte, Li3xLa2/3-xTiO3(LLTO), the ionic conductivity of grain boundaries is about three orders of magnitude lower than that of the bulk. In contrast, the related Li0.375Sr0.4375Ta0.75Zr0.25O3(LSTZ0.75) perovskite exhibits low grain boundary resistance for reasons yet unknown. Here, we use aberration-corrected scanning transmission electron microscopy and spectroscopy, along with an active learning moment tensor potential, to reveal the atomic scale structure and composition of LSTZ0.75 grain boundaries. Vibrational electron energy loss spectroscopy is applied for the first time to reveal atomically resolved vibrations at grain boundaries of LSTZ0.75 and to characterize the otherwise unmeasurable Li distribution therein. We find that Li depletion, which is a major reason for the low grain boundary ionic conductivity of LLTO, is absent for the grain boundaries of LSTZ0.75. Instead, the low grain boundary resistivity of LSTZ0.75 is attributed to the formation of a nanoscale defective cubic perovskite interfacial structure that contained abundant vacancies. Our study provides new insights into the atomic scale mechanisms of low grain boundary resistivity.
Carbon reduction technology pathways for existing buildings in eight cities
Authors: Ang Yu Qian , Berzolla Zachary Michael , Letellier-Duchesne Samuel , Reinhart Christoph F. 
Published: April 2023

AbstractWe work with policymakers in eight cities worldwide to identify technology pathways toward their near- and long-term carbon emissions reduction targets for existing buildings. Based on policymakers’ interests, we define city-specific shallow and deep retrofitting packages along with onsite photovoltaic generation potential. Without further grid decarbonization measures, stock-wide implementation of these retrofits in the investigated neighborhoods reduces energy use and carbon emissions by up to 66% and 84%, respectively, helping Braga, Dublin, Florianopolis, Middlebury, and Singapore to meet their 2030 goals. With projected grid decarbonization, Florianopolis and Singapore will reach their 2050 goals. The remaining emissions stem from municipalities not planning to electrify heating and/or domestic hot water use. Different climates and construction practices lead to varying retrofit packages, suggesting that comparable technology pathway analyses should be conducted for municipalities worldwide. Twenty months after the project ended, seven cities have implemented policy measures or expanded the analysis across their building stock.
Anomalous deep-red luminescence of perylene black analogues with strong π-π interactions
Authors: Tang Ningning , Zhou Jiadong , Wang Liangxuan , Stolte Matthias , Xie Guojing , Wen Xinbo , Liu Linlin , Würthner Frank , Gierschner Johannes , Xie Zengqi 
Published: April 2023

AbstractPerylene bisimide (PBI) dyes are known as red, maroon and black pigments, whose colors depend on the close π−π stacking arrangement. However, contrary to the luminescent monomers, deep-red and black PBI pigments are commonly non- or only weakly fluorescent due to (multiple) quenching pathways. Here, we introduce N-alkoxybenzyl substituted PBIs that contain close π stacking arrangement (exhibiting dπ−π ≈ 3.5 Å, and longitudinal and transversal displacements of 3.1 Å and 1.3 Å); however, they afford deep-red emitters with solid-state fluorescence quantum yields (ΦF) of up to 60%. Systematic photophysical and computational studies in solution and in the solid state reveal a sensitive interconversion of the PBI-centred locally excited state and a charge transfer state, which depends on the dihedral angle (θ) between the benzyl and alkoxy groups. This effectively controls the emission process, and enables high ΦF by circumventing the common quenching pathways commonly observed for perylene black analogues.
Mid-latitudinal habitable environment for marine eukaryotes during the waning stage of the Marinoan snowball glaciation
Authors: Song Huyue , An Zhihui , Ye Qin , Stüeken Eva E. , Li Jing , Hu Jun , Algeo Thomas J. , Tian Li , Chu Daoliang , Song Haijun , Xiao Shuhai , Tong Jinnan 
Published: April 2023

AbstractDuring the Marinoan Ice Age (ca. 654–635 Ma), one of the ‘Snowball Earth’ events in the Cryogenian Period, continental icesheets reached the tropical oceans. Oceanic refugia must have existed for aerobic marine eukaryotes to survive this event, as evidenced by benthic phototrophic macroalgae of the Songluo Biota preserved in black shales interbedded with glacial diamictites of the late Cryogenian Nantuo Formation in South China. However, the environmental conditions that allowed these organisms to thrive are poorly known. Here, we report carbon-nitrogen-iron geochemical data from the fossiliferous black shales and adjacent diamictites of the Nantuo Formation. Iron-speciation data document dysoxic-anoxic conditions in bottom waters, whereas nitrogen isotopes record aerobic nitrogen cycling perhaps in surface waters. These findings indicate that habitable open-ocean conditions were more extensive than previously thought, extending into mid-latitude coastal oceans and providing refugia for eukaryotic organisms during the waning stage of the Marinoan Ice Age.
Intercellular exchange of Wnt ligands reduces cell population heterogeneity during embryogenesis
Authors: Hatakeyama Yudai , Saito Nen , Mii Yusuke , Takada Ritsuko , Shinozuka Takuma , Takemoto Tatsuya , Naoki Honda , Takada Shinji 
Published: April 2023

AbstractWnt signaling is required to maintain bipotent progenitors for neural and paraxial mesoderm cells, the neuromesodermal progenitor (NMP) cells that reside in the epiblast and tailbud. Since epiblast/tailbud cells receive Wnt ligands produced by one another, this exchange may average out the heterogeneity of Wnt signaling levels among these cells. Here, we examined this possibility by replacing endogenous Wnt3a with a receptor-fused form that activates signaling in producing cells, but not in neighboring cells. Mutant mouse embryos show a unique phenotype in which maintenance of many NMP cells is impaired, although some cells persist for long periods. The epiblast cell population of these embryos increases heterogeneity in Wnt signaling levels as embryogenesis progresses and are sensitive to retinoic acid, an endogenous antagonist of NMP maintenance. Thus, mutual intercellular exchange of Wnt ligands in the epiblast cell population reduces heterogeneity and achieves robustness to environmental stress.
Electrified hydrocarbon-to-oxygenates coupled to hydrogen evolution for efficient greenhouse gas mitigation
Authors: Leow Wan Ru , Völker Simon , Meys Raoul , Huang Jianan Erick , Jaffer Shaffiq A. , Bardow André , Sargent Edward H. 
Published: April 2023

AbstractChemicals manufacture is among the top greenhouse gas contributors. More than half of the associated emissions are attributable to the sum of ammonia plus oxygenates such as methanol, ethylene glycol and terephthalic acid. Here we explore the impact of electrolyzer systems that couple electrically-powered anodic hydrocarbon-to-oxygenate conversion with cathodic H2 evolution reaction from water. We find that, once anodic hydrocarbon-to-oxygenate conversion is developed with high selectivities, greenhouse gas emissions associated with fossil-based NH3 and oxygenates manufacture can be reduced by up to 88%. We report that low-carbon electricity is not mandatory to enable a net reduction in greenhouse gas emissions: global chemical industry emissions can be reduced by up to 39% even with electricity having the carbon footprint per MWh available in the United States or China today. We conclude with considerations and recommendations for researchers who wish to embark on this research direction.
Carbon-sink potential of continuous alfalfa agriculture lowered by short-term nitrous oxide emission events
Authors: Anthony Tyler L. , Szutu Daphne J. , Verfaillie Joseph G. , Baldocchi Dennis D. , Silver Whendee L. 
Published: April 2023

AbstractAlfalfa is the most widely grown forage crop worldwide and is thought to be a significant carbon sink due to high productivity, extensive root systems, and nitrogen-fixation. However, these conditions may increase nitrous oxide (N2O) emissions thus lowering the climate change mitigation potential. We used a suite of long-term automated instrumentation and satellite imagery to quantify patterns and drivers of greenhouse gas fluxes in a continuous alfalfa agroecosystem in California. We show that this continuous alfalfa system was a large N2O source (624 ± 28 mg N2O m2 y−1), offsetting the ecosystem carbon (carbon dioxide (CO2) and methane (CH4)) sink by up to 14% annually. Short-term N2O emissions events (i.e., hot moments) accounted for ≤1% of measurements but up to 57% of annual emissions. Seasonal and daily trends in rainfall and irrigation were the primary drivers of hot moments of N2O emissions. Significant coherence between satellite-derived photosynthetic activity and N2O fluxes suggested plant activity was an important driver of background emissions. Combined data show annual N2O emissions can significantly lower the carbon-sink potential of continuous alfalfa agriculture.
TREM2+ and interstitial-like macrophages orchestrate airway inflammation in SARS-CoV-2 infection in rhesus macaques
Authors: Upadhyay Amit A. , Viox Elise G. , Hoang Timothy N. , Boddapati Arun K. , Pino Maria , Lee Michelle Y.-H. , Corry Jacqueline , Strongin Zachary , Cowan David A. , Beagle Elizabeth N. , Horton Tristan R. , Hamilton Sydney , Aoued Hadj , Harper Justin L. , Edwards Christopher T. , Nguyen Kevin , Pellegrini Kathryn L. , Tharp Gregory K. , Piantadosi Anne , Levit Rebecca D. , Amara Rama R. , Barratt-Boyes Simon M. , Ribeiro Susan P. , Sekaly Rafick P. , Vanderford Thomas H. , Schinazi Raymond F. , Paiardini Mirko , Bosinger Steven E. 
Published: April 2023

AbstractThe immunopathological mechanisms driving the development of severe COVID-19 remain poorly defined. Here, we utilize a rhesus macaque model of acute SARS-CoV-2 infection to delineate perturbations in the innate immune system. SARS-CoV-2 initiates a rapid infiltration of plasmacytoid dendritic cells into the lower airway, commensurate with IFNA production, natural killer cell activation, and a significant increase of blood CD14-CD16+ monocytes. To dissect the contribution of lung myeloid subsets to airway inflammation, we generate a longitudinal scRNA-Seq dataset of airway cells, and map these subsets to corresponding populations in the human lung. SARS-CoV-2 infection elicits a rapid recruitment of two macrophage subsets: CD163+MRC1-, and TREM2+ populations that are the predominant source of inflammatory cytokines. Treatment with baricitinib (Olumiant®), a JAK1/2 inhibitor is effective in eliminating the influx of non-alveolar macrophages, with a reduction of inflammatory cytokines. This study delineates the major lung macrophage subsets driving airway inflammation during SARS-CoV-2 infection.
Early indicators of tidal ecosystem shifts in estuaries
Authors: Fivash Gregory S. , Temmerman Stijn , Kleinhans Maarten G. , Heuner Maike , van der Heide Tjisse , Bouma Tjeerd J. 
Published: April 2023

AbstractForecasting transitions between tidal ecosystem states, such as between bare tidal flats and vegetated marshes, is crucial because it may imply the irreversible loss of valuable ecosystem services. In this study, we combine geospatial analyses of three European estuaries with a simple numerical model to demonstrate that the development of micro-topographic patterning on tidal flats is an early indicator of marsh establishment. We first show that the development of micro-topographic patterns precedes vegetation establishment, and that patterns tend to form only on tidal flats with a slope of <0.3 degrees. Numerical modelling then provides an explanation for the formation of micro-topography due to the natural concentration of draining surface water over very gentle slopes. We find this early indicator to be robust across three estuaries where anthropogenic deepening and narrowing has occurred in recent decades, which may suggest its broader applicability to other estuaries with similar morphological management.