bluuebunny/crossref_metadata_2025 huggingface dataset:
Contribution of Non‐Water Ices to Salinity and Electrical Conductivity in Ocean Worlds
Authors: Castillo‐Rogez J. C. , Daswani M. M. , Glein C. R. , Vance S. D. , Cochrane C. J.
Published: July 2022

Modeling of the electrical conductivity (EC) of icy moon oceans has previously assumed that chloride, sulfate, and other ions released from rock leaching are the main solutes and carriers of EC. Here, we show that accreted volatiles, such as carbon dioxide and ammonia, can add a significant fraction of solutes in bodies whose volatile content was in part supplied from cometary materials. These volatiles can increase the EC of aqueous solutions above 1 S/m. Our salinity and EC estimates can serve as a basis for planning future magnetometer investigations at icy moons and dwarf planets. In particular, oceans expected in some of the Uranian satellites and Neptune's satellite Triton could have EC above 3 S/m as a result of accretion of both carbon dioxide and ammonia, even if rock leaching during water‐rock separation was limited, and if chlorine and sulfur abundances may be at CI carbonaceous chondritic levels.
New Estimates of Southern Ocean Annual Net Community Production Revealed by BGC‐Argo Floats
Authors: Su Jiaoyang , Schallenberg Christina , Rohr Tyler , Strutton Peter G. , Phillips Helen E.
Published: July 2022

Using an expanding Southern Ocean fleet of biogeochemical Argo (BGC‐Argo) floats, we developed a novel approach to estimate annual net community production (ANCP) by integrating subsurface oxygen drawdown from all available BGC‐Argo oxygen profiles. Our results suggest that, on average, 14% of remineralization occurs between 500 and 1,000 m and 15% occurs between the euphotic depth and 100 m. Using the improved methodology, we estimated total basin‐integrated ANCP in the Southern Ocean to be 3.89 GT C year−1 suggesting a more important role for the Southern Ocean in regulating oceanic carbon storage, atmospheric CO2 exchange and climate than previously assumed.
River Plume Modulation by Infragravity Wave Forcing
Authors: Flores Raúl P. , Williams Megan E. , Horner‐Devine Alexander R.
Published: July 2022

We present measurements at the mouth of Río Maipo, a small river that discharges into an energetic surfzone on the coast of Chile, which document for the first time the plume response to infragravity (IG) wave forcing. We find that inlet dynamics are strongly modulated by IG waves; inlet discharge velocity varies by 20% in the IG band relative to peak ebb velocity. Drone imaging and measurements of surfzone salinity show that the plume edge is forced offshore and onshore, modifying plume width by 20%–50% at IG frequencies. We conclude that the observed modulation results from surfzone forcing at IG frequencies consistent with a moving break point; increased (decreased) wave amplitude generates stronger (weaker) wave‐driven circulation and forces the plume onshore (offshore). Although river water is often trapped in the surfzone, these dynamics may enhance mixing and cross‐shore dispersion of river‐borne materials.
Insights Into the Aerodynamic Versus Radiometric Surface Temperature Debate in Thermal‐Based Evaporation Modeling
Authors: Mallick Kaniska , Baldocchi Dennis , Jarvis Andrew , Hu Tian , Trebs Ivonne , Sulis Mauro , Bhattarai Nishan , Bossung Christian , Eid Yomna , Cleverly Jamie , Beringer Jason , Woodgate William , Silberstein Richard , Hinko‐Najera Nina , Meyer Wayne S. , Ghent Darren , Szantoi Zoltan , Boulet Gilles , Kustas William P.
Published: July 2022

Global evaporation monitoring from Earth observation thermal infrared satellite missions is historically challenged due to the unavailability of any direct measurements of aerodynamic temperature. State‐of‐the‐art one‐source evaporation models use remotely sensed radiometric surface temperature as a substitute for the aerodynamic temperature and apply empirical corrections to accommodate for their inequality. This introduces substantial uncertainty in operational drought mapping over complex landscapes. By employing a non‐parametric model, we show that evaporation can be directly retrieved from thermal satellite data without the need of any empirical correction. Independent evaluation of evaporation in a broad spectrum of biome and aridity yielded statistically significant results when compared with eddy covariance observations. While our simplified model provides a new perspective to advance spatio‐temporal evaporation mapping from any thermal remote sensing mission, the direct retrieval of aerodynamic temperature also generates the highly required insight on the critical role of biophysical interactions in global evaporation research.
Decomposition of Deglacial Pacific Radiocarbon Age Controls Using an Isotope‐Enabled Ocean Model
Authors: Zanowski Hannah , Jahn Alexandra , Gu Sifan , Liu Zhengyu , Marchitto Thomas M.
Published: July 2022

During the last deglaciation Earth’s climate experienced strong and abrupt variations, resulting in major changes in global temperature, sea level, and ocean circulation. Although proxy records have significantly improved our understanding of climate during this period, questions remain regarding the connection between ocean circulation evolution and resulting geotracer distributions, including those of deep waters in the Pacific. Here we use the C‐iTRACE simulation, a transient ocean‐only, isotope‐enabled version of the Community Earth System Model, to better understand deglacial deep Pacific radiocarbon evolution in the context of circulation and reservoir age changes. Throughout the deglaciation, the Pacific Ocean circulation in C‐iTRACE responds strongly to glacial meltwater forcing, leading to large changes in deep Pacific Δ14C age. A multi‐millennial weakening of the overturning circulation from 20 to 15 ka BP leads to increases in deep Pacific Δ14C ages, but from 20 to 18 ka BP, nearly half (40%–60%) of this aging is controlled by changing surface reservoir age, corroborating previous studies showing that Δ14C is not solely a circulation age tracer. As the deglaciation proceeds, circulation change controls progressively more of the Δ14C age, accounting for more than 75% of it across the deep Pacific from 15 to 8 ka BP.
Late‐Syn‐ to Post‐Rift Salt Tectonics on Wide Rifted Margins—Insights From Geodynamic Modeling
Authors: Pichel Leonardo M. , Huismans Ritske S. , Gawthorpe Robert , Faleide Jan Inge , Theunissen Thomas
Published: July 2022

Rifted margins are often associated with widespread and thick evaporite (salt) deposits and pronounced salt tectonics. The largest salt basins formed during the latest stages of rifting, immediately prior to continental breakup. Salt tectonics along these rifted margins commonly exhibit structural domains characterized by gravity‐driven updip extension, translation, downdip shortening, and salt nappe advance. The precise spatial and temporal links between these structural processes, their relative contributions and dynamics are still a topic of debate on many margins. We use 2D thermo‐mechanically coupled finite‐element modeling of lithospheric extension to investigate the evolution of salt tectonics along wide rifted margins and the interplay between rifting and post‐rift deformation. The models integrate lithospheric extension with post‐rift salt tectonics using a geodynamically self‐consistent approach where the geometries of the lithosphere and salt basins are not prescribed. They confirm that wide salt‐bearing rifted margins are characterized by gravity‐driven updip extension and downdip shortening, but also that syn‐depositional salt flow and salt stretching occurs in their distal portions prior to and during continental breakup. This produces widening of the basin and emplacement of a salt nappe over newly formed oceanic crust. Post‐rift updip extension is mostly balanced by downdip diapir shortening, all related to Couette flow. The salt nappe initiated by late syn‐rift stretching advances further by post‐rift pressure‐driven Poiseuille salt flow so that its final width is a product of both processes. The results can be directly compared to examples from various salt‐bearing rifted margins and improve our understanding of their enigmatic genesis and evolution.
The Mass Change Designated Observable Study: Overview and Results
Authors: Wiese D. N. , Bienstock B. , Blackwood C. , Chrone J. , Loomis B. D. , Sauber J. , Rodell M. , Baize R. , Bearden D. , Case K. , Horner S. , Luthcke S. , Reager J. T. , Srinivasan M. , Tsaoussi L. , Webb F. , Whitehurst A. , Zlotnicki V.
Published: July 2022

The 2017–2027 United States National Academy of Sciences Decadal Survey (DS) for Earth Science and Applications from Space identified Mass Change (MC) as one of five Designated Observables (DOs) having the highest priority in terms of Earth observations required to advance Earth system science over the next decade. In response to this designation, NASA initiated several multi‐center studies, with the goal of recommending observing system architectures for each DO for implementation within this decade. This paper provides an overview of the Mass Change Designated Observable (MCDO) Study along with key findings. The study process included: (a) generation of a Science and Applications Traceability Matrix (SATM) that maps required measurement parameters to the DS Science and Applications Objectives; (b) identification of three architecture classes relevant for measuring mass change: Precise Orbit Determination (POD), Satellite‐Satellite‐Tracking (SST) and Gravity Gradiometry (GG), along with variants within each architecture class; and (c) creation of a Value Framework process that considers science value, cost, risk, schedule, and partnership opportunities, to identify and recommend high value observing systems for further in‐depth study. The study team recommended the implementation of an SST architecture, and identified variants that simultaneously (a) satisfy the baseline measurement parameters of the SATM; (b) maximize the probability of providing overlap with the Gravity Recovery and Climate Experiment Follow‐On (GRACE‐FO) mission currently in operation, accelerating science return from both missions; and (c) provide a pathway towards substantial improvements in resolution and accuracy of mass change data products relative to the program of record.
Detection of Magma Beneath the Northern and Southern Rift Zones of Axial Seamount at the Juan de Fuca Ridge
Authors: Lee Michelle K. , Carbotte Suzanne M. , Arnulf Adrien F.
Published: July 2022

Axial Seamount is an active hotspot‐related volcanic system located along the Juan de Fuca Ridge (JdFR) that includes a central volcano and bounding northern and southern rift zones (NRZ and SRZ). Three documented volcanic eruptions in 1998, 2011, and 2015 included dike propagation into and eruptions within the rift zones that are believed to have been sourced from the well‐imaged large magma reservoir found beneath the central volcano. However, areas beyond the central volcano have not been explored for potential magma sources that could have contributed to these events, and geochemical studies of older rift zone lavas indicate differences in compositions suggestive of magma reservoirs fed by more mid‐ocean ridge‐dominated mantle sources. In this study, we analyze multichannel seismic data acquired in 2002 to characterize the internal crustal structure of the rift zones. The new reflectivity images reveal small (<5 km wide) and discontinuous crustal magma bodies at depths of ∼1.5 to 4 km beneath and in the vicinity of the rift zone lava flows from the three eruptions. We also image wide magma bodies within the overlap regions between the rift zones and neighboring segments of JdFR including a 6.4 km wide body under the east flank of NRZ and a 1‐km wide, ∼400 to 500 m, thick body near the base of the crust under the SRZ‐Vance overlap basin. Collectively the new observations indicate that multiple small crustal magma bodies underlie Axial segment, in addition to the main reservoir, and likely contribute to rift zone magmatism with implications for interpretations of seismicity patterns and lava flow compositions.
Increasing Health Risks During Outdoor Sports Due To Climate Change in Texas: Projections Versus Attitudes
Authors: Dee Sylvia G. , Nabizadeh Ebrahim , Nittrouer Christine L. , Baldwin Jane W. , Li Chelsea , Gaviria Lizzy , Guo Selena , Lu Karen , Saunders‐Shultz Beck Miguel , Gurwitz Emily , Samarth Gargi , Weinberger Kate R.
Published: July 2022

Extreme heat is a recognized threat to human health. This study examines projected future trends of multiple measures of extreme heat across Texas throughout the next century, and evaluates the expected climate changes alongside Texas athletic staff (coach and athletic trainer) attitudes toward heat and climate change. Numerical climate simulations from the recently published Community Earth System Model version 2 and the Climate Model Intercomparison Project were used to predict changes in summer temperatures, heat indices, and wet bulb temperatures across Texas and also within specific metropolitan areas. A survey examining attitudes toward the effects of climate change on athletic programs and student athlete health was also distributed to high‐school and university athletic staff. Heat indices are projected to increase beyond what is considered healthy/safe limits for outdoor sports activity by the mid‐to‐late 21st century. Survey results reveal a general understanding and acceptance of climate change and a need for adjustments in accordance with more dangerous heat‐related events. However, a portion of athletic staff still do not acknowledge the changing climate and its implications for student athlete health and their athletic programs. Enhancing climate change and health communication across the state may initiate important changes to athletic programs (e.g., timing, duration, intensity, and location of practices), which should be made in accordance with increasingly dangerous temperatures and weather conditions. This work employs a novel interdisciplinary approach to evaluate future heat projections alongside attitudes from athletic communities toward climate change.
Width‐Based Discharge Partitioning in Distributary Networks: How Right We Are
Authors: Hariharan Jayaram , Piliouras Anastasia , Schwenk Jon , Passalacqua Paola
Published: July 2022

River deltas are home to large populations and can be composed of complex channel networks which convey flows of matter to the shoreline. Knowledge of flow within individual channels is needed to quantify the distribution of discharge across the delta, and thus its sustainability over time. Due to a lack of field measurements at the local channel scale, researchers leverage remote sensing data to estimate the partitioning of flow. We compare data from 15 river deltas to discharge partitioning estimates based on channel network graphs derived from remote sensing imagery. We quantify errors in the common width‐based method and test alternative partitioning techniques to find that width‐based discharge partitioning is universally applicable, suggesting that absent any site‐specific information, discharge partitioning by average channel width is an appropriate approach. We also provide networks, streamflow measurements, and flux partitioning estimates for 28 delta networks as the Discharge In Distributary NeTworks (DIDNT) dataset.
Observational Evidence of Generation and Propagation of Barotropic Rossby Waves Induced by Tropical Instability Waves in the Northeastern Pacific
Authors: Lee Kang‐Nyeong , Jeon Chanhyung , Seung YoungHo , Shin Hong‐Ryeol , Son Seung‐Kyu , Park Jae‐Hun
Published: July 2022

Tropical instability waves (TIWs) in the equatorial eastern Pacific exhibit 25–40‐day westward‐propagating fluctuations with seasonal and interannual variations, which are stronger during July–December and La Niña periods. There is evidence that the instability of the equatorial currents that generates TIWs also induce radiation of barotropic Rossby waves (BTRWTIW). Long‐term near‐bottom current measurements at 10.5°N and 131.3°W during 2004–2013 revealed a spectral peak at 25–40 days, where significant coherences were found with satellite‐measured sea surface height with maxima approximately 5°N. Simulated deep currents from a data‐assimilated ocean model concur with the observed near‐bottom currents, and both currents vary seasonally and interannually, consistent with the typical characteristics of TIW. Further analyses using 25–40‐day bandpass‐filtered barotropic velocity data from the model revealed that they reasonably satisfied the theoretical dispersion relation of BTRWTIW. The in situ and model analysis support the conclusion that BTRWTIW propagate north of 10°N in the northeastern Pacific.
Core Surface Flow Changes Associated With the 2017 Pacific Geomagnetic Jerk
Authors: Whaler K. A. , Hammer M. D. , Finlay C. C. , Olsen N.
Published: July 2022

A geomagnetic jerk was seen in Swarm satellite data in 2017 over the Pacific region. We invert time series of spatial gradient secular variation data between 2014 and 2020, reduced to a grid of points at satellite altitude, for spatially‐ and temporally‐regularized core surface flow. Pacific region flow acceleration was almost constant before and after the jerk, with a sharp change, especially in the azimuthal component, at the jerk epoch, despite the temporal regularization. Azimuthal acceleration is oppositely signed either side of 160°W, where it effectively vanishes, and also reverses sign at the jerk epoch. Acceleration features drift westward at about 900 km year−1. Unlike previous studies, the evidence presented here for low latitude waves does not depend on imposing flow equatorial symmetry, quasi‐ or tangential geostrophy, or band‐pass filtering, and has no reliance on stochastic models or numerical simulations.
Fugitive Gas Migration in the Vadose Zone at an Experimental Field Site in the Montney Shale Gas Region
Authors: Forde Olenka N. , Cahill Aaron G. , Mayer Bernhard , Beckie Roger D. , Mayer K. Ulrich
Published: July 2022

Fugitive gas migration (GM) from compromised oil and gas wells remains a global concern. To understand environmental impacts from GM there is a need to characterize the transport and fate of fugitive gas in the vadose zone. We simulated subsurface wellbore leakage by injecting natural gas into thick unsaturated glacio‐lacustrine deposits in a region of petroleum development in Western Canada. Methane and carbon dioxide effluxes were monitored and soil‐gas samples were collected for molecular and stable carbon isotope analyses. A conceptual model was developed to demonstrate the physical and biogeochemical processes that control the spatial‐temporal variability of GM. Methane oxidation partially attenuated natural gas; however, gas transport and fate were strongly influenced by variations in grain‐size distribution and barometric pressure, resulting in episodic effluxes and lateral gas transport. To accurately detect, quantify and assess GM at oil and gas sites, adequate site characterization and continuous, spatially dense monitoring are necessary.
Electron Energization Signatures in Traveling Kinetic Alfvén Waves at Storm Time Injection Fronts
Authors: Hull A. J. , Damiano P. A. , Chaston C. C. , Johnson J. R. , Reeves G. D.
Published: July 2022

The properties of traveling kinetic Alfvén waves (KAWs) and their role in energizing electrons in the inner magnetosphere during a geomagnetic storm are examined using measurements from the Van Allen Probes and Gyrofluid‐Kinetic Electron (GKE) model simulations. Traveling KAWs occur in the vicinity of energetic plasma injection fronts in association with magnetic field dipolarizations. The KAWs coincide with energized field‐aligned electrons at energies ≲1 keV. By using observational constraints and incorporating hot and cold electron populations, the GKE simulations are able to reproduce the observed energized electron distribution signatures. The modeling results demonstrate the crucial importance of cold electrons for best observational agreement. The results show that the electron response to KAWs can be substantially different for opposing current regions and are a sensitive function of the cold electron relative density.
Active Silica Diagenesis in the Deepest Hadal Trench Sediments
Authors: Luo Min , Li Weiding , Geilert Sonja , Dale Andrew W. , Song Zijun , Chen Duofu
Published: July 2022

Porewater dissolved silicic acid (DSi) concentrations and stable Si isotope compositions (δ30Si) together with biogenic silica (bSiO2) contents of sediments in five sediment cores collected from the southern Mariana Trench are presented. These data suggest the occurrence of bSiO2 dissolution and concomitant authigenic clay formation in three bSiO2‐bearing cores. A reaction‐transport model constrained by the measured geochemical data was applied to quantify the rates of Si turnover. Model results predicted the greatest rates of both bSiO2 dissolution and authigenic clay formation at the trench axis core that displayed low bSiO2 contents and abundant detrital materials, suggesting that detrital materials may be a limiting factor for bSiO2 diagenesis. Model results further predicted that ∼40%–70% of DSi generated by bSiO2 dissolution is consumed by authigenic clay formation. This is the first study that demonstrates active silica diagenesis in the hadal realm and has implications for understanding benthic Si cycling in deep‐sea settings.
Spectral Analysis of the Martian Atmospheric Turbulence: InSight Observations
Authors: Temel Orkun , Senel Cem Berk , Spiga Aymeric , Murdoch Naomi , Banfield Don , Karatekin Ozgur
Published: July 2022

In this study, we perform spectral analysis of Martian near‐surface turbulence using the in‐situ observations by NASA's InSight lander on Mars. A recent study on the daytime Martian boundary layer using the InSight observations showed that the conventional Kolmogorov energy cascade of inertial subrange fails to predict the spectral density of pressure (Banfield et al., 2020, https://doi.org/10.1038/s41561-020-0544-y). Here we extend this by investigating diurnal and seasonal variations in the spectral density of pressure, as the indicator of the Martian atmospheric turbulence. We show distinct spectral behaviors for the daytime and nighttime conditions. Moreover, we report the important effects of regional dust storms, gravity waves (GWs), bore, and solitary waves on the turbulent energy cascade. Our results show that the presence of a dust storm and GW activity can enhance the turbulence of the nighttime boundary layer of Mars despite the extreme stably stratified conditions compared to the terrestrial case.
Ongoing Lithospheric Alteration of the North China Craton Revealed by Surface‐Wave Tomography and Geodetic Observations
Authors: Feng J. K. , Yao H. J. , Chen L. , Li C. L.
Published: July 2022

The North China Craton (NCC) is renowned for cratonic reactivation and dramatic destruction. Detailed lithospheric structure is crucial for understanding the geological evolution and seismogenesis of the NCC. We imaged the lithospheric structure of the central and eastern NCC with ambient noise and teleseismic surface wave tomography. Our new model unveils remarkable N‐S variation in the lithospheric structure. An E‐W elongated lithospheric weak zone, coinciding with contemporary left‐lateral shearing revealed by geodetic observation, occupies the northern central and eastern NCC. Our model suggests that radical destruction of the eastern NCC in the late Mesozoic facilitated the late‐Cenozoic shearing induced by the continuous India‐Eurasia convergence. The late‐Cenozoic shearing progressively altered the pre‐thinned lithosphere accompanied by asthenospheric upwelling and strong seismic activity. Our results suggest a transition from the Pacific subduction dominating tectonic regime to the India‐Asia collision dominating lithospheric deformation framework in the Cenozoic and ongoing lithospheric alteration of the NCC.
On the Relation Between Active Network Length and Catchment Discharge
Authors: Durighetto Nicola , Botter Gianluca
Published: July 2022

The ever‐changing hydroclimatic conditions of the landscape induce ceaseless variations in the wet channel length (L) and the streamflow (Q) of a catchment. Here we use a perceptual model to analyze the links among (and the drivers of) four descriptors commonly used to characterize discharge and active length dynamics in streams, namely the L(Q) relationship and the cumulative distributions of local persistency, flowrate and active length. The model demonstrates that the shape of the L(Q) law is defined by the cumulative distribution of the specific subsurface discharge capacity along the network, a finding which provides a clue for the parametrization of L(Q) relations in dynamic streams. Furthermore, we show that L(Q) laws can be constructed combining the streamflow distribution with disjoint active length data. Our framework links previously unconnected formulations for characterizing stream network dynamics, and offers a novel perspective to describe the scaling between wet length and discharge in rivers.
Earthquake Fingerprint of an Incipient Subduction of a Bathymetric High
Authors: Passarelli Luigi , Cesca Simone , Nooshiri Nima , Jónsson Sigurjón
Published: July 2022

The resistance of bathymetric highs to subduction results in large‐scale morphological distortions of the outer‐rise, trench, and fore‐arc regions. Once subducted, bathymetric highs induce frictional segmentation along the plate interface that may result in increase or decrease of the plate coupling. However, the mechanics of the collision is inferred mostly from geophysical and geological surveys since earthquakes rarely illuminate finer details of the subduction of seafloor relief. A year‐long and energetic seismic sequence at the Loyalty Ridge (LR)‐Vanuatu Trench allowed us to characterize how strain is released along the collision zone. Earthquakes revealed complex fracturing in the outer‐rise and fore‐arc regions and segmentation of the interface with both limited magnitude events and aftershock productivity. The complex earthquake activity associated to the collision and subduction of the LR appears to support a frictionally segmented interface where Mw ≥ 8 megathrust earthquakes are unlikely to nucleate.
QBO and ENSO Effects on the Mean Meridional Circulation, Polar Vortex, Subtropical Westerly Jets, and Wave Patterns During Boreal Winter
Authors: Kumar Vinay , Yoden Shigeo , Hitchman Matthew H.
Published: July 2022

The joint influence of the stratospheric quasi‐biennial oscillation (QBO) and the El Niño Southern Oscillation (ENSO) on the polar vortex, subtropical westerly jets (STJs), and wave patterns during boreal winter is investigated in 40 years (1979–2018) of monthly mean ERA‐Interim reanalyses. The method of Wallace et al. (1993), https://doi.org/10.1175/15200469(1993)050<1751:ROTESQ>2.0.CO;2 is used to conduct a QBO phase angle sweep. QBO westerly (W) and easterly (E) composites are then segregated by the phase of ENSO. Two pathways are described by which the QBO mean meridional circulation (MMC) influences the northern winter hemisphere. The “stratospheric pathway” modulates stratospheric planetary wave absorption via the Holton‐Tan mechanism. The “tropospheric pathway” modulates the tropical and subtropical upper troposphere and lower stratosphere. QBO MMC anomalies exhibit a checkerboard pattern in temperature and arched structures in zonal wind which extend into midlatitudes, and are stronger on the winter side. During QBO W, the polar vortex and STJs are enhanced. QBO signals in the polar vortex are amplified during La Niña. During El Niño and QBO W, the strongest STJs occur, and a warm pole/wave two pattern is found. During El Niño and QBO E, a trough is found over Eurasia and a ridge over the North Atlantic, in a wave one pattern. El Niño diminishes QBO anomalies in the tropical stratosphere and reduces the poleward extent and amplitude of the QBO MMC, thereby influencing the stratospheric pathway. Effects on the boreal winter hemisphere are attributed to the combined influence of the QBO and ENSO via both pathways.
Physiographic Controls and Wildfire Effects on Aquatic Biogeochemistry in Tundra of the Yukon‐Kuskokwim Delta, Alaska
Authors: Zolkos Scott , MacDonald Erin , Hung Jacqueline K. Y. , Schade John D. , Ludwig Sarah , Mann Paul J. , Treharne Rachael , Natali Susan
Published: July 2022

Northern high‐latitude deltas are hotspots of biogeochemical processing, terrestrial‐aquatic connectivity, and, in Alaska's Yukon‐Kuskokwim Delta (YKD), tundra wildfire. Yet, wildfire effects on aquatic biogeochemistry remain understudied in northern delta regions, thus limiting a more comprehensive understanding of high latitude biogeochemical cycles. In this study, we assess wildfire impacts on summertime aquatic biogeochemistry in YKD tundra using a multi‐year (2015–2019) data set of water chemistry measurements (n = 406) from five aquatic environments: peat plateau ponds, fen ponds, fen channels, lakes, and streams. We aimed to (a) characterize variation in hydrochemistry among aquatic environments; (b) determine wildfire effects on hydrochemistry; and (c) assess post‐fire multi‐year patterns in hydrochemistry in lakes (lower terrestrial‐freshwater connectivity) and fen ponds (higher connectivity). Variation in hydrochemistry among environments was more strongly associated with watershed characteristics (e.g., terrestrial‐aquatic connectivity) than wildfire. However, certain hydrochemical constituents showed consistent wildfire effects. Decreases in dissolved organic carbon (DOC) and CO2, and increases in pH, specific conductance, NH4+, and NO3− indicate that, by combusting soil organic matter, wildfire reduces organics available for hydrologic transport and microbial respiration, and mobilizes nitrogen into freshwaters. Multi‐year post‐fire variation in specific conductance, DOC, and CO2 in lakes and fen ponds suggest that watershed characteristics underlie ecosystem response and recovery to wildfire in the YKD. Together, these results indicate that increasing tundra wildfire occurrence at northern high latitudes could drive multi‐year shifts toward stronger aquatic inorganic nutrient cycling, and that variation in terrain characteristics is likely to underlie wildfire effects on aquatic ecosystems across broader scales.
Observation of polarity-switchable photoconductivity in III-nitride/MoSx core-shell nanowires
Authors: Wang Danhao , Wu Wentiao , Fang Shi , Kang Yang , Wang Xiaoning , Hu Wei , Yu Huabin , Zhang Haochen , Liu Xin , Luo Yuanmin , He Jr-Hau , Fu Lan , Long Shibing , Liu Sheng , Sun Haiding
Published: July 2022

III–V semiconductor nanowires are indispensable building blocks for nanoscale electronic and optoelectronic devices. However, solely relying on their intrinsic physical and material properties sometimes limits device functionalities to meet the increasing demands in versatile and complex electronic world. By leveraging the distinctive nature of the one-dimensional geometry and large surface-to-volume ratio of the nanowires, new properties can be attained through monolithic integration of conventional nanowires with other easy-synthesized functional materials. Herein, we combine high-crystal-quality III-nitride nanowires with amorphous molybdenum sulfides (a-MoSx) to construct III-nitride/a-MoSx core-shell nanostructures. Upon light illumination, such nanostructures exhibit striking spectrally distinctive photodetection characteristic in photoelectrochemical environment, demonstrating a negative photoresponsivity of −100.42 mA W−1 under 254 nm illumination, and a positive photoresponsivity of 29.5 mA W−1 under 365 nm illumination. Density functional theory calculations reveal that the successful surface modification of the nanowires via a-MoSx decoration accelerates the reaction process at the electrolyte/nanowire interface, leading to the generation of opposite photocurrent signals under different photon illumination. Most importantly, such polarity-switchable photoconductivity can be further tuned for multiple wavelength bands photodetection by simply adjusting the surrounding environment and/or tailoring the nanowire composition, showing great promise to build light-wavelength controllable sensing devices in the future.
Origin, virological features, immune evasion and intervention of SARS-CoV-2 Omicron sublineages
Authors: Xia Shuai , Wang Lijue , Zhu Yun , Lu Lu , Jiang Shibo
Published: July 2022

Recently, a large number of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants continuously emerged and posed a major threat to global public health. Among them, particularly, Omicron variant (B.1.1.529), first identified in November 2021, carried numerous mutations in its spike protein (S), and then quickly spread around the world. Currently, Omicron variant has expanded into more than one hundred sublineages, such as BA.1, BA.2, BA.2.12.1, BA.4 and BA.5, which have already become the globally dominant variants. Different from other variants of concern (VOCs) of SARS-CoV-2, the Omicron variant and its sublineages exhibit increased transmissibility and immune escape from neutralizing antibodies generated through previous infection or vaccination, and have caused numerous re-infections and breakthrough infections. In this prospective, we have focused on the origin, virological features, immune evasion and intervention of Omicron sublineages, which will benefit the development of next-generation vaccines and therapeutics, including pan-sarbecovirus and universal anti-CoV therapeutics, to combat currently circulating and future emerging Omicron sublineages as well as other SARS-CoV-2 variants.
Long non-coding RNA DLEU1 promotes malignancy of breast cancer by acting as an indispensable coactivator for HIF-1α-induced transcription of CKAP2
Authors: Ma He Nan , Chen Hai Jun , Liu Ji Quan , Li Wen Tao
Published: July 2022

Earlier studies have suggested deleted in lymphocytic leukemia 1 (DLEU1), a long non-coding RNA, is a prognostic biomarker for breast cancer. Here we explored the malignant behaviors and underlying mechanisms regulated by DLEU1 in breast cancer. We demonstrated that up-regulation of DLEU1 was detected in breast cancer tissues and cells, particularly in tumors of higher malignancy. DLEU1 knockdown inhibited the growth and the motility of breast cancer cells. Mechanistically, DLEU1 interacted with HIF-1α to collectively activate the transcription of CKAP2. By activating ERK and STAT3 signaling, CKAP2 essentially mediated the pro-tumor activities of DLEU1. In vivo, depletion of DLEU1 inhibited xenograft growth and metastasis of breast cancer cells. Therefore, DLEU1, by acting as a coactivator for HIF-1α, up-regulates CKAP2 expression and promotes malignancy of breast cancer. Targeting DLEU1, HIF-1α, or CKAP2 may thus benefit breast cancer treatment.
Drought-Induced Civil Conflict Among the Ancient Maya
Authors: Kennett Douglas J. , Masson Marilyn , Lope Carlos Peraza , Serafin Stanley , George Richard J. , Spencer Tom C. , Hoggarth Julie A. , Culleton Brendan J. , Harper Thomas K. , Prufer Keith M. , Milbrath Susan , Russell Bradley W. , González Eunice Uc , McCool Weston C. , Aquino Valorie V. , Paris Elizabeth H. , Curtis Jason H. , Marwan Norbert , Zhang Mingua , Asmerom Yemane , Polyak Victor J. , Carolin Stacy A. , James Daniel H. , Mason Andrew J. , Henderson Gideon M. , Brenner Mark , Baldini James U. L. , Breitenbach Sebastian F. M. , Hodell David A.
Published: July 2022

The influence of climate change on civil conflict and societal instability in the premodern world is a subject of much debate, in part because of the limited temporal or disciplinary scope of case studies. We present a transdisciplinary case study that combines archeological, historical, and paleoclimate datasets to explore the dynamic, shifting relationships among climate change, civil conflict, and political collapse at Mayapan, the largest Postclassic Maya capital of the Yucatán Peninsula in the thirteenth and fourteenth centuries CE. Multiple data sources indicate that civil conflict increased significantly and generalized linear modeling correlates strife in the city with drought conditions between 1400 and 1450 cal. CE. We argue that prolonged drought escalated rival factional tensions, but subsequent adaptations reveal regional-scale resiliency, ensuring that Maya political and economic structures endured until European contact in the early sixteenth century CE.
Increased neutralization and IgG epitope identification after MVA-MERS-S booster vaccination against Middle East respiratory syndrome
Authors: Fathi Anahita , Dahlke Christine , Krähling Verena , Kupke Alexandra , Okba Nisreen M. A. , Raadsen Matthijs P. , Heidepriem Jasmin , Müller Marcel A. , Paris Grigori , Lassen Susan , Klüver Michael , Volz Asisa , Koch Till , Ly My L. , Friedrich Monika , Fux Robert , Tscherne Alina , Kalodimou Georgia , Schmiedel Stefan , Corman Victor M. , Hesterkamp Thomas , Drosten Christian , Loeffler Felix F. , Haagmans Bart L. , Sutter Gerd , Becker Stephan , Addo Marylyn M.
Published: July 2022

Vaccine development is essential for pandemic preparedness. We previously conducted a Phase 1 clinical trial of the vector vaccine candidate MVA-MERS-S against the Middle East respiratory syndrome coronavirus (MERS-CoV), expressing its full spike glycoprotein (MERS-CoV-S), as a homologous two-dose regimen (Days 0 and 28). Here, we evaluate the safety (primary objective) and immunogenicity (secondary and exploratory objectives: magnitude and characterization of vaccine-induced humoral responses) of a third vaccination with MVA-MERS-S in a subgroup of trial participants one year after primary immunization. MVA-MERS-S booster vaccination is safe and well-tolerated. Both binding and neutralizing anti-MERS-CoV antibody titers increase substantially in all participants and exceed maximum titers observed after primary immunization more than 10-fold. We identify four immunogenic IgG epitopes, located in the receptor-binding domain (RBD, n = 1) and the S2 subunit (n = 3) of MERS-CoV-S. The level of baseline anti-human coronavirus antibody titers does not impact the generation of anti-MERS-CoV antibody responses. Our data support the rationale of a booster vaccination with MVA-MERS-S and encourage further investigation in larger trials. Trial registration: Clinicaltrials.gov NCT03615911.
Microporous polymer adsorptive membranes with high processing capacity for molecular separation
Authors: Wang Zhenggong , Luo Xiaofan , Song Zejun , Lu Kuan , Zhu Shouwen , Yang Yanshao , Zhang Yatao , Fang Wangxi , Jin Jian
Published: July 2022

Trade-off between permeability and nanometer-level selectivity is an inherent shortcoming of membrane-based separation of molecules, while most highly porous materials with high adsorption capacity lack solution processability and stability for achieving adsorption-based molecule separation. We hereby report a hydrophilic amidoxime modified polymer of intrinsic microporosity (AOPIM-1) as a membrane adsorption material to selectively adsorb and separate small organic molecules from water with ultrahigh processing capacity. The membrane adsorption capacity for Rhodamine B reaches 26.114 g m−2, 10–1000 times higher than previously reported adsorptive membranes. Meanwhile, the membrane achieves >99.9% removal of various nano-sized organic molecules with water flux 2 orders of magnitude higher than typical pressure-driven membranes of similar rejections. This work confirms the feasibility of microporous polymers for membrane adsorption with high capacity, and provides the possibility of adsorptive membranes for molecular separation.
α-Synuclein fibril-specific nanobody reduces prion-like α-synuclein spreading in mice
Authors: Butler Yemima R. , Liu Yuqing , Kumbhar Ramhari , Zhao Peiran , Gadhave Kundlik , Wang Ning , Li Yanmei , Mao Xiaobo , Wang Wenjing
Published: July 2022

Pathogenic α-synuclein (α-syn) is a prion-like protein that drives the pathogenesis of Lewy Body Dementia (LBD) and Parkinson’s Disease (PD). To target pathogenic α-syn preformed fibrils (PFF), here we designed extracellular disulfide bond-free synthetic nanobody libraries in yeast. Following selection, we identified a nanobody, PFFNB2, that can specifically recognize α-syn PFF over α-syn monomers. PFFNB2 cannot inhibit the aggregation of α-syn monomer, but can significantly dissociate α-syn fibrils. Furthermore, adeno-associated virus (AAV)-encoding EGFP fused to PFFNB2 (AAV-EGFP-PFFNB2) can inhibit PFF-induced α-syn serine 129 phosphorylation (pS129) in mouse primary cortical neurons, and prevent α-syn pathology spreading to the cortex in the transgenic mice expressing human wild type (WT) α-syn by intrastriatal-PFF injection. The pS129 immunoreactivity is negatively correlated with the expression of AAV-EGFP-PFFNB2. In conclusion, PFFNB2 holds a promise for mechanistic exploration and therapeutic development in α-syn-related pathogenesis.
Multiple valence bands convergence and strong phonon scattering lead to high thermoelectric performance in p-type PbSe
Authors: Zhu Yingcai , Wang Dongyang , Hong Tao , Hu Lei , Ina Toshiaki , Zhan Shaoping , Qin Bingchao , Shi Haonan , Su Lizhong , Gao Xiang , Zhao Li-Dong
Published: July 2022

Thermoelectric generators enable the conversion of waste heat to electricity, which is an effective way to alleviate the global energy crisis. However, the inefficiency of thermoelectric materials is the main obstacle for realizing their widespread applications and thus developing materials with high thermoelectric performance is urgent. Here we show that multiple valence bands and strong phonon scattering can be realized simultaneously in p-type PbSe through the incorporation of AgInSe2. The multiple valleys enable large weighted mobility, indicating enhanced electrical properties. Abundant nano-scale precipitates and dislocations result in strong phonon scattering and thus ultralow lattice thermal conductivity. Consequently, we achieve an exceptional ZT of ~ 1.9 at 873 K in p-type PbSe. This work demonstrates that a combination of band manipulation and microstructure engineering can be realized by tuning the composition, which is expected to be a general strategy for improving the thermoelectric performance in bulk materials.
Coastal ecological impacts from pumice rafts
Authors: Ohno Yoshikazu , Iguchi Akira , Ijima Mariko , Yasumoto Ko , Suzuki Atsushi
Published: July 2022

An explosive volcanic eruption occurred in the Ogasawara Islands on 13–15 August 2021, bringing unprecedented amounts of floating pumice to the coast of Okinawa Island in the Ryukyu Archipelago, 1300 km west of the volcano, approximately 2 months later. The coast of Okinawa Island, especially along the northern part, is home to many typical subtropical seascapes, including coral reefs and mangrove forests, so the possible impact of the large amount of pumice is attracting attention. Here, we report early evidence of ecosystem changes as a result of large-scale pumice stranding on coastal beaches, in estuaries and mangrove forests and passage across fringing coral reefs. Massive pumice drifts are major obstacles to fishing activities and ship traffic, but short and long-term changes in coastal ecosystems can also occur. The phenomena observed on Okinawa Island can be a preview of coastal impacts for the Kyushu, Shikoku, Honshu Islands, where pumice has subsequently washed ashore.
Effects of intermittent hypoxia with thrombin in an in vitro model of human brain endothelial cells and their impact on PAR-1/PAR-3 cleavage
Authors: Zolotoff Cindy , Puech Clémentine , Roche Frédéric , Perek Nathalie
Published: July 2022

Patients with obstructive sleep apnea/hypopnea (OSA) are at high risk of cerebrovascular diseases leading to cognitive impairment. The oxidative stress generated by intermittent hypoxia (IH) could lead to an increase in blood–brain barrier (BBB) permeability, an essential interface for the protection of the brain. Moreover, in patients with OSA, blood coagulation could be increased leading to cardiovascular complications. Thrombin is a factor found increased in these populations that exerts various cellular effects through activation of protease activated receptors (PARs). Thus, we have evaluated in an in vitro BBB model the association of IH with thrombin at two concentrations. We measured the apparent BBB permeability, expression of tight junctions, ROS production, HIF-1α expression, and cleavage of PAR-1/PAR-3. Pre-treatment with dabigatran was performed. IH and higher thrombin concentrations altered BBB permeability: high levels of HIF-1α expression, ROS and PAR-1 activation compared to PAR-3 in such conditions. Conversely, lower concentration of thrombin associated with IH appear to have a protective effect on BBB with a significant cleavage of PAR-3. Dabigatran reversed the deleterious effect of thrombin at high concentrations but also suppressed the beneficial effect of low dose thrombin. Therefore, thrombin and PARs represent novel attractive targets to prevent BBB opening in OSA.
Borate-guided ribose phosphorylation for prebiotic nucleotide synthesis
Authors: Hirakawa Yuta , Kakegawa Takeshi , Furukawa Yoshihiro
Published: July 2022

Polymers of ribonucleotides (RNAs) are considered to store genetic information and promote biocatalytic reactions for the proto life on chemical evolution. Abiotic synthesis of ribonucleotide was successful in past experiments; nucleoside synthesis occurred first, followed by phosphorylation. These abiotic syntheses are far from biotic reactions and have difficulties as a prebiotic reaction in reacting chemicals in a specific order and purifying intermediates from other molecules in multi-steps of reactions. Another reaction, ribose phosphorylation followed by nucleobase synthesis or nucleobase addition, is close to the biotic reactions of nucleotide synthesis. However, the synthesis of ribose 5′-phosphate under prebiotically plausible conditions remains unclear. Here, we report a high-yield regioselective one-pot synthesis of ribose 5′-phosphate from an aqueous solution containing ribose, phosphate, urea, and borate by simple thermal evaporation. Of note, phosphorylation of ribose before the nucleoside formation differs from the traditional prebiotic nucleotide syntheses and is also consistent with biological nucleotide synthesis. Phosphorylation occurred to the greatest extent in ribose compared to other aldopentoses, only in the presence of borate. Borate is known to improve the stability of ribose preferentially. Geological evidence suggests the presence of borate-rich settings on the early Earth. Therefore, borate-rich evaporitic environments could have facilitated preferential synthesis of ribonucleotide coupled with enhanced stability of ribose on the early Earth.
Depolarization imaging for fast and non-invasive monitoring of cervical microstructure remodeling in vivo during pregnancy
Authors: Rehbinder Jean , Vizet Jérémy , Park Junha , Ossikovski Razvigor , Vanel Jean-Charles , Nazac André , Pierangelo Angelo
Published: July 2022

The cervix plays a crucial role in conception, maintenance of pregnancy, and childbirth. The mechanical properties of a pregnant woman's cervix change dramatically during gestation due to a remodeling of its microstructure, necessary for delivery. However, external factors can accelerate this process and lead to prematurity, the primary cause of perinatal mortality worldwide, due to the inefficiency of existing diagnostic methods. This study shows that polarized light is a powerful tool to probe the cervical microstructure during pregnancy. A wide-field multispectral polarimetric imaging system was fabricated to explore in vivo the cervix of full-term pregnant women. The polarimetric properties of the cervix change significantly with pregnancy progression. In particular, a set of several depolarization parameters (intrinsic and extrinsic) showed a strong linear correlation with gestational age in the red part of the visible spectral range. This trend can be attributed, among other things, to a decrease in collagen density and an increase in hydration of cervical connective tissue. Wide field depolarization imaging is a very promising tool for rapid and non-invasive analysis of cervical tissue in vivo to monitor the steady progression of pregnancy, providing the practitioner with useful information to improve the detection of preterm birth.