bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantifying Nitrous Oxide Emissions in the U.S. Midwest: A Top‐Down Study Using High Resolution Airborne In‐Situ Observations
Authors: Eckl Maximilian , Roiger Anke , Kostinek Julian , Fiehn Alina , Huntrieser Heidi , Knote Christoph , Barkley Zachary R. , Ogle Stephen M. , Baier Bianca C. , Sweeney Colm , Davis Kenneth J.
Published: January 2021

The densely farmed U.S. Midwest is a prominent source of nitrous oxide (N2O) but top‐down and bottom‐up N2O emission estimates differ significantly. We quantify Midwest N2O emissions by combining observations from the Atmospheric Carbon and Transport‐America campaign with model simulations to scale the Emissions Database for Global Atmospheric Research (EDGAR). In October 2017, we scaled agricultural EDGAR v4.3.2 and v5.0 emissions by factors of 6.3 and 3.5, respectively, resulting in 0.42 nmol m−2 s−1 Midwest N2O emissions. In June/July 2019, a period when extreme flooding was occurring in the Midwest, agricultural scaling factors were 11.4 (v4.3.2) and 9.9 (v5.0), resulting in 1.06 nmol m−2 s−1 Midwest emissions. Uncertainties are on the order of 50 %. Agricultural emissions estimated with the process‐based model DayCent (Daily version of the CENTURY ecosystem model) were larger than in EDGAR but still substantially smaller than our estimates. The complexity of N2O emissions demands further studies to fully characterize Midwest emissions.
Molecular Dynamics Simulations of Dielectric Breakdown of Lunar Regolith: Implications for Water Ice Formation on Lunar Surface
Authors: Huang Ziyu , Nomura Ken‐ichi , Nakano Aiichiro , Wang Joseph
Published: January 2021

Molecular dynamics simulations are carried out to investigate dielectric breakdown of lunar regolith induced by space weather events and its potential effects on water ice formation on lunar surface. We find that dielectric breakdown can trigger the water formation process by breaking the chemical bonds of regolith grains and exposing the oxygen atoms to react with the hydrogen implanted by solar wind. In the permanently shadowed region, the water molecules formed become attached to regolith grains in the molecular structure of ice after the event. Thus, dielectric breakdown can also enable the preservation of water molecules by changing the hydrophobicity of regolith grains.
Longitudinal Differences in Electron Temperature on Both Sides of Zero Declination Line in the Mid‐latitude Topside Ionosphere
Authors: Ma Han , Liu Libo , Chen Yiding , Le Huijun , Li Qiaoling , Zhang Hui
Published: January 2021

In this study, electron temperature (Te) observations from the Defense Meteorological Satellite Program F17 and F18 spacecraft during 2010–2017 are analyzed to explore the longitudinal differences of Te in the topside ionosphere on both sides of zero geomagnetic declination lines in the northern mid‐latitude under geomagnetically weak activities (Kp3). Te in the North American sector (45ºW–135ºW) has prominent longitudinal differences on sector scale. Te increases from the west side to east side in the morning, but vice versa in the afternoon. The relative value of longitudinal differences in Te peaks in May to August. The East Asian sector (45ºE–135ºE) of similar geomagnetic field configurations is selected for verification. There are similar local time and seasonal dependencies in the two sectors, while the intensity of longitudinal differences of Te weakens in the latter sector. The estimation of contributions to the longitudinal difference of Te from thermosphere winds provided by the empirical horizontal wind model (HWM14), peak height (hmF2) and peak density (NmF2) of the F2 layer indicates that the magnetic declination modulation effect of neutral winds at mid‐latitudes changes electron density (Ne), which indirectly changes the longitudinal difference in Te. Furthermore, the zonal wind at different local times and the seasonal variation of meridional winds may be the main effect factors of dependencies in Te longitudinal differences. The sector longitudinal differences of both geomagnetic declination and horizontal winds are possibly major reasons causing the different intensity of this characteristic in the two sectors.
Statistical Correlation Analysis Between Thermal Infrared Anomalies Observed From MTSATs and Large Earthquakes Occurred in Japan (2005–2015)
Authors: Genzano N. , Filizzola C. , Hattori K. , Pergola N. , Tramutoli V.
Published: January 2021

The literature often reports space–time relations between the abnormal variations of different kinds of nonseismological (i.e., geophysical, geochemical, and atmospheric) parameters and the occurrence of earthquakes. The integration of such observations with seismological ones could improve the quality of the seismic hazard assessment in the medium‐short term (months to days). Each considered parameter has, in principle, its capabilities to provide useful (and utilizable) information about seismic processes. Therefore, to define a system based on different observations, the first step is to estimate the informative contribution that each considered parameter could provide. In this paper, we will evaluate the potential of Significant Sequence of Thermal Anomalies (SSTAs). In particular, we adopted the broadly used Robust Satellite Techniques (RST) data analysis methodology to identify SSTAs over 11 years (June 2005 to December 2015) of nighttime satellite images acquired by MTSAT satellites over Japan. Aiming at reducing the false‐positive rate, we introduced and tested an innovative configuration of the RST, which is here presented. We executed a correlation analysis between SSTAs and Japanese earthquakes with MJMA ≥ 6 by applying suitable constraints concerning space, time, and magnitude. The analysis highlights (a) the occurrence of just 29 SSTAs in the 11‐year period of observation, (b) 18 SSTAs (i.e., 62%) occur in an apparent space–time relation to earthquakes, and (c) 13 of them occur before the quake. Results of the random test analysis, based on error diagrams, confirm a noncasual correlation between “RST‐based satellite thermal anomalies” and earthquake occurrences. In particular, for MJMA ≥ 6.5 earthquakes, probability gain is up to better than 4.3 as compared with the random guess.
Slab Models Beneath Central Myanmar Revealed by a Joint Inversion of Regional and Teleseismic Traveltime Data
Authors: Yao Jiayuan , Liu Shaolin , Wei Shengji , Hubbard Judith , Huang Bor‐Shouh , Chen Meng , Tong Ping
Published: January 2021

The intermediate‐depth (50–180 km) seismicity beneath Myanmar provides direct evidence of the subducting Indian slab. However, the historic lack of regional seismic observations leads to previous low‐resolution models that show large variations in slab geometry beneath Myanmar. The depth extent and morphology of the slab are still poorly known. In this study, we conduct a joint inversion of regional and teleseismic P‐wave traveltimes from recently installed networks to image seismic velocity structures beneath central Myanmar by adopting an eikonal equation‐based traveltime tomography method. The observations contain a total of 6,069 regional first P‐wave arrivals and 29,787 teleseismic P‐wave differential traveltimes. We find a high P‐wave velocity anomaly beneath central Myanmar, which starts from ∼50 km depth and extends continuously to the mantle transition zone (MTZ) and is interpreted as the subducting Indian slab. Below 100 km depth, the dip angle of the slab in the south is ∼15° larger than that of the slab in the north, suggesting a possible slab tearing. Based on our tomographic results and previous studies, the slab in the north is inferred to have a deep stagnant segment lying above the 660‐km discontinuity in the MTZ, but whether it is connected with the shallow dipping slab cannot be confirmed. Meanwhile, the slab in the south may just stay in the upper mantle (above 410 km), but it may also have penetrated the 410‐km discontinuity. Taking into account all the scenarios, we propose four possible models of the Indian Plate subduction system beneath central Myanmar.
Momentum Flux Convergence From Internal Tides in the North Equatorial Countercurrent Upstream of a Submarine Ridge Near Merir Island, Palau
Authors: Johnston T. M. Shaun , Ou Celia Y.
Published: January 2021

In the presence of a mean flow, theory and models for internal tide generation at small‐amplitude topography show (a) internal tides produce a net momentum flux that extends to the surface and (b) fluxes are directed preferentially upstream. Here, we observe internal tides propagating into the North Equatorial Countercurrent during two spatial surveys near a submarine ridge. On the second survey during a diurnal spring tide, we note elevated shear upstream of the ridge below 112 m with corresponding low Richardson numbers, which suggests the internal waves are dissipating due to shear instability. Reduced amplitudes are noted above 150 m. Internal tidal motions were isolated by performing a phase average over a wavelength upstream of the topography. Momentum flux convergence and divergence are noted upstream of the ridge, have a similar magnitude to mean flow acceleration terms, and are about 10% of the largest mean flow terms. The internal tides were noted upstream and appeared weaker downstream, but due to the topographic wake similar calculations could not be performed downstream. Tall, steep topography and strong equatorial currents are found throughout the low‐latitude western Pacific, which suggests such infrequently observed internal tide flux divergences may be commonly contributing to the momentum of mean flows.
Observations of Ice Nucleating Particles in the Free Troposphere From Western US Wildfires
Authors: Barry Kevin R. , Hill Thomas C. J. , Levin Ezra J. T. , Twohy Cynthia H. , Moore Kathryn A. , Weller Zachary D. , Toohey Darin W. , Reeves Mike , Campos Teresa , Geiss Roy , Schill Gregory P. , Fischer Emily V. , Kreidenweis Sonia M. , DeMott Paul J.
Published: January 2021

Wildfires in the western United States are large sources of particulate matter, and the area burned by wildfires is predicted to increase in the future. Some particles released from wildfires can affect cloud formation by serving as ice‐nucleating particles (INPs). INPs have numerous impacts on cloud radiative properties and precipitation development. Wildfires are potentially important sources of INPs, as indicated from previous measurements, but their abundance in the free troposphere has not been quantified. The Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption, and Nitrogen campaign sampled free tropospheric immersion‐freezing INPs from smoke plumes near their source and downwind, along with widespread aged smoke. The results indicate an enhancement of INPs in smoke plumes relative to out‐of‐plume background air, but the magnitude of enhancement was both temperature and fire dependent. The majority of INPs were inferred to be predominately organic in composition with some contribution from biological sources at modest super cooling, and contributions from minerals at deeper super cooling. A fire involving primarily sagebrush shrub land and aspen forest fuels had the highest INP concentrations measured in the campaign, which is partially attributed to the INP characteristics of lofted, uncombusted plant material. Electron microscopy analysis of INPs also indicated tar balls present in this fire. Parameterization of the plume INP data on a per‐unit‐aerosol surface area basis confirmed that smoke is not an efficient source of INPs. Nevertheless, the high numbers of particles released from, and ubiquity of western US wildfires in summertime, regionally elevate INP concentrations in the free troposphere.
Evidence for Coupling Between the Subseasonal Oscillations in the Southern Hemisphere Midlatitude Ocean and Atmosphere
Authors: Xue Daokai , Lu Jian , Qian Yun , Zhang Yaocun
Published: January 2021

A regional perspective is taken to investigate the intriguing ∼25‐day periodicity in the Southern Hemisphere (SH) baroclinic annular mode (BAM) and the possible underlying mechanisms. Results show that the 25‐day periodicity exists not only in the zonal average but also in the regional average of eddy activity as long as the domain of the average is wide enough to accommodate a wave packet. The favorable domain for the ∼25 days periodicity is located downstream of the largest baroclinicity in midlatitudes. The wave activity developed there can travel circumglobally several times with a typical group velocity of 25 m s−1, and reenter the domain every 12.5 days, setting the base periodicity. A slower oceanic oscillation at a time scale of ∼100 days in the same region appears to select and reinforce the multiples of 12.5 days, giving rise to a pronounced ∼25‐day periodicity in the wave activity.
Generation Possibility of Gamma‐Ray Glows Induced by Photonuclear Reactions
Authors: Diniz G. S. , Ferreira I. S. , Wada Y. , Enoto T.
Published: January 2021

Relativistic runaway electron avalanches (RREAs) imply a large multiplication of high‐energy electrons (∼1 MeV). Two factors are necessary for this phenomenon: a high electric field sustained over a large distance and an energetic particle to serve as a seed. The former sustains particle energies as they keep colliding and lose energy randomly; and the latter serves as a multiplication starting point that promotes avalanches. RREA is usually connected to both terrestrial gamma‐ray flashes (TGFs) and gamma‐ray glows (also known as Thunderstorm Ground Enhancement (TGE) when detected at ground level) as possible generation mechanism of both events, but the current knowledge does not provide a clear relationship between these events (TGF and TGE), beyond their possible common source mechanism, still as they have different characteristics. In particular, their timescales differ by several orders of magnitude. This work shows that chain reactions by TGF byproducts can continue for the timescale of gamma‐ray glows and even provide energetic particles as seeds for RREAs of gamma‐ray glows.
Mars: Abundant Recurring Slope Lineae (RSL) Following the Planet‐Encircling Dust Event (PEDE) of 2018
Authors: McEwen Alfred S. , Schaefer Ethan I. , Dundas Colin M. , Sutton Sarah S. , Tamppari Leslie K. , Chojnacki Matthew
Published: January 2021

Recurring slope lineae (RSL) are dark linear markings on Mars that regrow annually and likely originate from the flow of either liquid water or granular material. Following the great dust storm (or planet‐encircling dust event, PEDE) of Mars year (MY) 34, Mars Reconnaissance Orbiter/High Resolution Imaging Science Experiment has seen many more candidate RSL than in typical Mars years. They have been imaged at more than 285 unique locations from August 2018 (when the atmosphere was clearing as the PEDE decayed) to August 2019, about half (157) of which are locations where RSL have not been documented previously. In MY34, 150 active RSL sites were identified in the southern middle latitudes (SML, ‐60° to ‐30°), whereas an average of 36 active sites were observed in each previous year (MY28–33). Post‐PEDE RSL are also present during southern summer over a wider range of latitude, slope aspect, andLs(areocentric longitude of the sun) than in prior years. These RSL sites usually show evidence for recent dust deposition: obscuration of relatively dark areas, an overall brighter and redder surface than in prior years, and dust devil tracks, which indicate dust lifting by several mechanisms. We speculate that dust‐lifting processes may initiate and sustain RSL activity. The RSL may form from flows of dust (perhaps clumped) and/or sand that is destabilized by dust movement or directly mobilized by dust devils. If this is the case, then the otherwise puzzling recurrence and year‐to‐year variability of RSL activity can be at least partly explained. The dust replenishment varies from year to year, which could explain interannual variations in RSL activity.
Constraining the Temporal Variability of Neutral Winds in Saturn's Low‐Latitude Ionosphere Using Magnetic Field Measurements
Authors: Agiwal Omakshi , Cao H. , Cowley S. W. H. , Dougherty M. K. , . Hunt G. J , Müller‐Wodarg I. , Achilleos N.
Published: January 2021

The Cassini spacecraft completed 22 orbits around Saturn known as the “Grand Finale” over a 5 months interval, during which time the spacecraft traversed the previously unexplored region between Saturn and its equatorial rings near periapsis. The magnetic field observations reveal the presence of temporally variable low‐latitude field‐aligned currents which are thought to be driven by velocity shears in the neutral zonal winds at magnetically conjugate thermospheric latitudes. We consider atmospheric waves as a plausible driver of temporal variability in the low‐latitude thermosphere, and empirically constrain the region in which they perturb the zonal flows to be between ±25° latitude. By investigating an extensive range of hypothetical wind profiles, we present and analyze a timeseries of the modeled velocity shears in thermospheric zonal flows, with direct comparisons to empirically inferred angular velocity shears from the Bϕ observations. We determine the maximum temporal variability in the peak neutral zonal winds over the Grand Finale interval to be ∼350 m/s assuming steady‐state ionospheric Pedersen conductances. We further show that the ionospheric currents measured must be in steady‐state on ∼10 min timescales, and axisymmetric over ∼2 h of local time in the near‐equatorial ionosphere. Our study illustrates the potential to use of magnetospheric datasets to constrain atmospheric variability in the thermosphere region.
Geologic and Thermal Characterization of Oxia Planum Using Mars Odyssey THEMIS Data
Authors: Gary‐Bicas C. E. , Rogers A. D.
Published: January 2021

Oxia Planum will be the landing site for the European Space Agency ExoMars 2022 “Rosalind Franklin” mission to conduct astrobiological and geological experiments investigating the region's past. Previous orbital short‐wave infrared (SWIR, 1.0–2.6 μm) spectroscopic studies reported widespread phyllosilicate detections in the region suggesting possible alteration of its original lithology by past aqueous activity. We used thermal infrared data (TIR, 6.8–14.8 μm) from the Thermal Emission Imaging System to assess regional bulk composition and thermophysical properties. We coupled these assessments with SWIR spectral analyses from the Compact Reconnaissance Imaging Spectrometer for Mars and with high‐resolution visible images to characterize the physical properties of the region. We cataloged four geologic units with varying spectral, thermophysical, and textural properties. The previously mapped phyllosilicate bearing materials are associated with our oldest mapped unit. This unit exhibits light/dark‐toned interbedding and TIR spectral characteristics consistent with phyllosilicate dominated and/or intermediate volcanic lithologies; evidence for mafic materials is lacking. Superposing that unit is a thin patchy dark‐toned unit that contains mafic signatures. Isolated locations within the region are superposed by a mechanically competent, rough unit that lacks mafic signatures and is interpreted as lava or well‐cemented fluvial deposits. The uppermost mapped unit is an eroded fan of possible deltaic or alluvial origin, with an inferred surface composition of unconsolidated sediment. Finally, based on stratigraphic and cross‐cutting relationships with ejecta from Kilkhampton crater nearby, we suggest that all units formed during or before the Early Hesperian period.
The German Climate Forecast System: GCFS
Authors: Fröhlich Kristina , Dobrynin Mikhail , Isensee Katharina , Gessner Claudia , Paxian Andreas , Pohlmann Holger , Haak Helmuth , Brune Sebastian , Früh Barbara , Baehr Johanna
Published: January 2021

Seasonal prediction is one important element in a seamless prediction chain between weather forecasts and climate projections. After several years of development in collaboration with Universität Hamburg and Max Planck Institute for Meteorology, the Deutscher Wetterdienst performs operational seasonal forecasts since 2016 with the German Climate Forecast System, now in Version 2 (GCFS2.0). Here, the configuration of the previous system GCFS1.0 and the current GCFS2.0 are described and the performance of the two systems is compared over the common hindcast period of 1990–2014. In GCFS2.0, the forecast skill is improved compared to GCFS1.0 during boreal winter, especially for the Northern Hemisphere where the Pearson correlation has increased for the North Atlantic Oscillation index. Overall, a similar performance of GCFS2.0 in comparison to GCFS1.0 is assessed during the boreal summer. Future developments for climate forecasts need a stronger focus on the performance of interannual variability in a model system.
Exploration of Synthetic Terrestrial Snow Mass Estimation via Assimilation of AMSR‐E Brightness Temperature Spectral Differences Using the Catchment Land Surface Model and Support Vector Machine Regression
Authors: Wang Jing , Forman Barton A. , Xue Yuan
Published: January 2021

This study explores improvements in the estimation of snow water equivalent (SWE) over snow‐covered terrain using an ensemble‐based data assimilation (DA) framework. The NASA Catchment land surface model is used as the prognostic model in the assimilation of Advanced Microwave Scanning Radiometer for EOS passive microwave (PMW) brightness temperature spectral differences (ΔTb) where support vector machine regression is employed as the observation operator. A series of synthetic twin experiments are conducted using different precipitation boundary conditions. The results show, at times, DA degrades modeled SWE estimates (compared to the land surface model without assimilation) over complex terrain. To mitigate this degradation, a physically informed approach using different ΔTb for shallow‐to‐medium or medium‐to‐deep snow conditions along with a “data‐thinning” strategy is explored. Overall, both strategies improve the model ability to encapsulate more of the evaluation data and mitigate model ensemble collapse. The physically informed DA and 3‐days thinning DA strategies show marginal improvements of basin‐averaged SWE in terms of reduction of bias from 10 mm (baseline DA) to−5.2 mm and −2.5 mm, respectively. When the estimated forcings are greater than the truth, the baseline DA, physically informed DA, and 3‐days thinning DA improve SWE the most with ∼30%, 31%, and 24% reduction of RMSE (relative to OL), respectively. Overall, these results highlight the limited utility of PMW ΔTb observations in the estimation of snow in complex terrain, but do demonstrate that a physically based constraint approach and data thinning strategy can add more utility to the ΔTb observations in the estimation of SWE.
Independent and cumulative coeliac disease-susceptibility loci are associated with distinct disease phenotypes
Authors: Cerqueira Juliana X. M. , Saavalainen Päivi , Kurppa Kalle , Laurikka Pilvi , Huhtala Heini , Nykter Matti , L. E. Koskinen Lotta , Yohannes Dawit A. , Kilpeläinen Elina , Shcherban Anastasia , Palotie Aarno , Kaukinen Katri , Lindfors Katri
Published: January 2021

The phenotype of coeliac disease varies considerably for incompletely understood reasons. We investigated whether established coeliac disease susceptibility variants (SNPs) are individually or cumulatively associated with distinct phenotypes. We also tested whether a polygenic risk score (PRS) based on genome-wide associated (GWA) data could explain the phenotypic variation. The phenotypic association of 39 non-HLA coeliac disease SNPs was tested in 625 thoroughly phenotyped coeliac disease patients and 1817 controls. To assess their cumulative effects a weighted genetic risk score (wGRS39) was built, and stratified by tertiles. In our PRS model in cases, we took the summary statistics from the largest GWA study in coeliac disease and tested their association at eight P value thresholds (PT) with phenotypes. Altogether ten SNPs were associated with distinct phenotypes after correction for multiple testing (PEMP2 ≤ 0.05). The TLR7/TLR8 locus was associated with disease onset before and the SH2B3/ATXN2, ITGA4/UBE2E3 and IL2/IL21 loci after 7 years of age. The latter three loci were associated with a more severe small bowel mucosal damage and SH2B3/ATXN2 with type 1 diabetes. Patients at the highest wGRS39 tertiles had OR > 1.62 for having coeliac disease-related symptoms during childhood, a more severe small bowel mucosal damage, malabsorption and anaemia. PRS was associated only with dermatitis herpetiformis (PT = 0.2, PEMP2 = 0.02). Independent coeliac disease-susceptibility loci are associated with distinct phenotypes, suggesting that genetic factors play a role in determining the disease presentation. Moreover, the increased number of coeliac disease susceptibility SNPs might predispose to a more severe disease course.
Comorbid anxiety-like behavior in a rat model of colitis is mediated by an upregulation of corticolimbic fatty acid amide hydrolase
Authors: Vecchiarelli Haley A. , Morena Maria , Keenan Catherine M. , Chiang Vincent , Tan Kaitlyn , Qiao Min , Leitl Kira , Santori Alessia , Pittman Quentin J. , Sharkey Keith A. , Hill Matthew N.
Published: January 2021

Peripheral inflammatory conditions, including those localized to the gastrointestinal tract, are highly comorbid with psychiatric disorders such as anxiety and depression. These behavioral symptoms are poorly managed by conventional treatments for inflammatory diseases and contribute to quality of life impairments. Peripheral inflammation is associated with sustained elevations in circulating glucocorticoid hormones, which can modulate central processes, including those involved in the regulation of emotional behavior. The endocannabinoid (eCB) system is exquisitely sensitive to these hormonal changes and is a significant regulator of emotional behavior. The impact of peripheral inflammation on central eCB function, and whether this is related to the development of these behavioral comorbidities remains to be determined. To examine this, we employed the trinitrobenzene sulfonic acid-induced model of colonic inflammation (colitis) in adult, male, Sprague Dawley rats to produce sustained peripheral inflammation. Colitis produced increases in behavioral measures of anxiety and elevations in circulating corticosterone. These alterations were accompanied by elevated hydrolytic activity of the enzyme fatty acid amide hydrolase (FAAH), which hydrolyzes the eCB anandamide (AEA), throughout multiple corticolimbic brain regions. This elevation of FAAH activity was associated with broad reductions in the content of AEA, whose decline was driven by central corticotropin releasing factor type 1 receptor signaling. Colitis-induced anxiety was reversed following acute central inhibition of FAAH, suggesting that the reductions in AEA produced by colitis contributed to the generation of anxiety. These data provide a novel perspective for the pharmacological management of psychiatric comorbidities of chronic inflammatory conditions through modulation of eCB signaling.
Symbiotic associations of the deepest recorded photosynthetic scleractinian coral (172 m depth)
Authors: Rouzé Héloïse , Galand Pierre E , Medina Mónica , Bongaerts Pim , Pichon Michel , Pérez-Rosales Gonzalo , Torda Gergely , Moya Aurelie ,   Under The Pole Consortium, Bardout G , Périé-Bardout E , Marivint E , Lagarrigue G , Leblond J , Gazzola F , Pujolle S , Mollon N , Mittau A , Fauchet J , Paulme N , Pete R , Peyrusse K , Ferucci A , Magnan A , Horlaville M , Breton C , Gouin M , Markocic T , Jubert I , Herrmann P , Raina Jean-Baptiste , Hédouin Laetitia
Published: January 2021

The symbiosis between scleractinian corals and photosynthetic algae from the family Symbiodiniaceae underpins the health and productivity of tropical coral reef ecosystems. While this photosymbiotic association has been extensively studied in shallow waters (<30 m depth), we do not know how deeper corals, inhabiting large and vastly underexplored mesophotic coral ecosystems, modulate their symbiotic associations to grow in environments that receive less than 1% of surface irradiance. Here we report on the deepest photosymbiotic scleractinian corals collected to date (172 m depth), and use amplicon sequencing to identify the associated symbiotic communities. The corals, identified as Leptoseris hawaiiensis, were confirmed to host Symbiodiniaceae, predominantly of the genus Cladocopium, a single species of endolithic algae from the genus Ostreobium, and diverse communities of prokaryotes. Our results expand the reported depth range of photosynthetic scleractinian corals (0–172 m depth), and provide new insights on their symbiotic associations at the lower depth extremes of tropical coral reefs.
Mapping the adaptive landscape of a major agricultural pathogen reveals evolutionary constraints across heterogeneous environments
Authors: Dutta Anik , Hartmann Fanny E , Francisco Carolina Sardinha , McDonald Bruce A , Croll Daniel
Published: January 2021

The adaptive potential of pathogens in novel or heterogeneous environments underpins the risk of disease epidemics. Antagonistic pleiotropy or differential resource allocation among life-history traits can constrain pathogen adaptation. However, we lack understanding of how the genetic architecture of individual traits can generate trade-offs. Here, we report a large-scale study based on 145 global strains of the fungal wheat pathogen Zymoseptoria tritici from four continents. We measured 50 life-history traits, including virulence and reproduction on 12 different wheat hosts and growth responses to several abiotic stressors. To elucidate the genetic basis of adaptation, we used genome-wide association mapping coupled with genetic correlation analyses. We show that most traits are governed by polygenic architectures and are highly heritable suggesting that adaptation proceeds mainly through allele frequency shifts at many loci. We identified negative genetic correlations among traits related to host colonization and survival in stressful environments. Such genetic constraints indicate that pleiotropic effects could limit the pathogen’s ability to cause host damage. In contrast, adaptation to abiotic stress factors was likely facilitated by synergistic pleiotropy. Our study illustrates how comprehensive mapping of life-history trait architectures across diverse environments allows to predict evolutionary trajectories of pathogens confronted with environmental perturbations.
Novel dichloromethane-fermenting bacteria in the Peptococcaceae family
Authors: Holland Sophie I , Ertan Haluk , Montgomery Kate , Manefield Michael J , Lee Matthew
Published: January 2021

Dichloromethane (DCM; CH2Cl2) is a toxic groundwater pollutant that also has a detrimental effect on atmospheric ozone levels. As a dense non-aqueous phase liquid, DCM migrates vertically through groundwater to low redox zones, yet information on anaerobic microbial DCM transformation remains scarce due to a lack of cultured organisms. We report here the characterisation of DCMF, the dominant organism in an anaerobic enrichment culture (DFE) capable of fermenting DCM to the environmentally benign product acetate. Stable carbon isotope experiments demonstrated that the organism assimilated carbon from DCM and bicarbonate via the Wood–Ljungdahl pathway. DCMF is the first anaerobic DCM-degrading population also shown to metabolise non-chlorinated substrates. It appears to be a methylotroph utilising the Wood–Ljungdahl pathway for metabolism of methyl groups from methanol, choline, and glycine betaine. The flux of these substrates from subsurface environments may either directly (DCM, methanol) or indirectly (choline, glycine betaine) affect the climate. Community profiling and cultivation of cohabiting taxa in culture DFE without DCMF suggest that DCMF is the sole organism in this culture responsible for substrate metabolism, while the cohabitants persist via necromass recycling. Genomic and physiological evidence support placement of DCMF in a novel genus within the Peptococcaceae family, ‘Candidatus Formimonas warabiya’.
A pediatric case of productive cough caused by novel variants in DNAH9
Authors: Takeuchi Kazuhiko , Xu Yifei , Ogawa Satoru , Ikejiri Makoto , Nakatani Kaname , Gotoh Shimpei , Usui Satoko , Masuda Sawako , Nagao Mizuho , Fujisawa Takao
Published: January 2021

We report the first Japanese case of primary ciliary dyskinesia caused by DNAH9 variations. The patient, a 5-year-old girl, had repeated episodes of productive cough after contracting the common cold at the age of 1 year and 6 months. She did not have a situs abnormality or congenital heart defect. We identified two novel DNAH9 variants, NM_001372.3: c. [1298C>G];[5547_5550delTGAC], (p.[Ser433Cys];[Asp1850fs]).
Upper limits on the extent of seafloor anoxia during the PETM from uranium isotopes
Authors: Clarkson Matthew O. , Lenton Timothy M. , Andersen Morten B. , Bagard Marie-Laure , Dickson Alexander J. , Vance Derek
Published: January 2021

The Paleocene Eocene Thermal Maximum (PETM) represents a major carbon cycle and climate perturbation that was associated with ocean de-oxygenation, in a qualitatively similar manner to the more extensive Mesozoic Oceanic Anoxic Events. Although indicators of ocean de-oxygenation are common for the PETM, and linked to biotic turnover, the global extent and temporal progression of de-oxygenation is poorly constrained. Here we present carbonate associated uranium isotope data for the PETM. A lack of resolvable perturbation to the U-cycle during the event suggests a limited expansion of seafloor anoxia on a global scale. We use this result, in conjunction with a biogeochemical model, to set an upper limit on the extent of global seafloor de-oxygenation. The model suggests that the new U isotope data, whilst also being consistent with plausible carbon emission scenarios and observations of carbon cycle recovery, permit a maximum ~10-fold expansion of anoxia, covering <2% of seafloor area.
Charged particle guiding and beam splitting with auto-ponderomotive potentials on a chip
Authors: Zimmermann Robert , Seidling Michael , Hommelhoff Peter
Published: January 2021

Electron and ion beams are indispensable tools in numerous fields of science and technology, ranging from radiation therapy to microscopy and lithography. Advanced beam control facilitates new functionalities. Here, we report the guiding and splitting of charged particle beams using ponderomotive forces created by the motion of charged particles through electrostatic optics printed on planar substrates. Shape and strength of the potential can be locally tailored by the lithographically produced electrodes’ layout and the applied voltages, enabling the control of charged particle beams within precisely engineered effective potentials. We demonstrate guiding of electrons and ions for a large range of energies (from 20 to 5000 eV) and masses (from 5 · 10−4 to 131 atomic mass units) as well as electron beam splitting for energies up to the keV regime as a proof-of-concept for more complex beam manipulation.
Waveguide photoreactor enhances solar fuels photon utilization towards maximal optoelectronic – photocatalytic synergy
Authors: Loh Joel Y. Y. , Mohan Abhinav , Flood Andrew G. , Ozin Geoffery A. , Kherani Nazir P.
Published: January 2021

A conventional light management approach on a photo-catalyst is to concentrate photo-intensity to enhance the catalytic rate. We present a counter-intuitive approach where light intensity is distributed below the electronic photo-saturation limit under the principle of light maximization. By operating below the saturation point of the photo-intensity induced hydroxide growth under reactant gaseous H2+CO2 atmosphere, a coating of defect engineered In2O3-x(OH)y nanorod Reverse Water Gas Shift solar-fuel catalyst on an optical waveguide outperforms a coated plane by a factor of 2.2. Further, light distribution along the length of the waveguide increases optical pathlengths of the weakly absorptive green and yellow wavelengths, which increases CO product rate by a factor of 8.1-8.7 in the visible. Synergistically pairing with thinly doped silicon on the waveguide enhances the CO production rate by 27% over the visible. In addition, the persistent photoconductivity behavior of the In2O3-x(OH)y system enables CO production at a comparable rate for 2 h after turning off photo-illumination, enhancing yield with 44-62% over thermal only yield. The practical utility of persistent photocatalysis was demonstrated through outdoor solar concentrator tests, which after a day-and-night cycle showed CO yield increase of 19% over a day-light only period.
Sequencing of the Arabidopsis NOR2 reveals its distinct organization and tissue-specific rRNA ribosomal variants
Authors: Sims Jason , Sestini Giovanni , Elgert Christiane , von Haeseler Arndt , Schlögelhofer Peter
Published: January 2021

Despite vast differences between organisms, some characteristics of their genomes are conserved, such as the nucleolus organizing region (NOR). The NOR is constituted of multiple, highly repetitive rDNA genes, encoding the catalytic ribosomal core RNAs which are transcribed from 45S rDNA units. Their precise sequence information and organization remain uncharacterized. Here, using a combination of long- and short-read sequencing technologies we assemble contigs of the Arabidopsis NOR2 rDNA domain. We identify several expressed rRNA gene variants which are integrated into translating ribosomes in a tissue-specific manner. These findings support the concept of tissue specific ribosome subpopulations that differ in their rRNA composition and provide insights into the higher order organization of NOR2.
Elucidating different pattern of immunoregulation in BALB/c and C57BL/6 mice and their F1 progeny
Authors: Hartmann Wiebke , Blankenhaus Birte , Brunn Marie-Luise , Meiners Jana , Breloer Minka
Published: January 2021

Helminths are large multicellular parasites that infect one quarter of the human population. To prolong their survival, helminths suppress the immune responses of their hosts. Strongyloides ratti delays its expulsion from the gut by induction of regulatory circuits in a mouse strain-specific manner: depletion of Foxp3+ regulatory T cells (Treg) improves the anti-S. ratti immunity in BALB/c but not in C57BL/6 mice. In the current study we compare the hierarchy of immunoregulatory pathways in BALB/c, C57BL/6 mice and their F1 progeny (BALB/c × C57BL/6). Using multicolor flow cytometry, we show that S. ratti induces a distinct pattern of inhibitory checkpoint receptors by Foxp3+ Treg and Foxp3− T cells. Intensity of expression was highest in C57BL/6 and lowest in BALB/c mice, while the F1 cross had an intermediate phenotype or resembled BALB/c mice. Treg subsets expanded during infection in all three mouse strains. Similar to BALB/c mice, depletion of Treg reduced intestinal parasite burden and increased mucosal mast cell activation in S. ratti-infected F1 mice. Our data indicate that Treg dominate the regulation of immune responses in BALB/c and F1 mice, while multiple regulatory layers exist in C57BL/6 mice that may compensate for the absence of Treg.
Connectivity-informed drainage network generation using deep convolution generative adversarial networks
Authors: Kim Sung Eun , Seo Yongwon , Hwang Junshik , Yoon Hongkyu , Lee Jonghyun
Published: January 2021

Stochastic network modeling is often limited by high computational costs to generate a large number of networks enough for meaningful statistical evaluation. In this study, Deep Convolutional Generative Adversarial Networks (DCGANs) were applied to quickly reproduce drainage networks from the already generated network samples without repetitive long modeling of the stochastic network model, Gibb’s model. In particular, we developed a novel connectivity-informed method that converts the drainage network images to the directional information of flow on each node of the drainage network, and then transforms it into multiple binary layers where the connectivity constraints between nodes in the drainage network are stored. DCGANs trained with three different types of training samples were compared; (1) original drainage network images, (2) their corresponding directional information only, and (3) the connectivity-informed directional information. A comparison of generated images demonstrated that the novel connectivity-informed method outperformed the other two methods by training DCGANs more effectively and better reproducing accurate drainage networks due to its compact representation of the network complexity and connectivity. This work highlights that DCGANs can be applicable for high contrast images common in earth and material sciences where the network, fractures, and other high contrast features are important.
SARS-CoV-2 infection susceptibility influenced by ACE2 genetic polymorphisms: insights from Tehran Cardio-Metabolic Genetic Study
Authors: Lanjanian Hossein , Moazzam-Jazi Maryam , Hedayati Mehdi , Akbarzadeh Mahdi , Guity Kamran , Sedaghati-khayat Bahareh , Azizi Fereidoun , Daneshpour Maryam S.
Published: January 2021

The genetic variations among individuals are one of the notable factors determining disease severity and drug response. Nowadays, COVID-19 pandemic has been adversely affecting many aspects of human life. We used the Tehran Cardio-Metabolic Genetic Study (TCGS) data that is an ongoing genetic study including the whole-genome sequencing of 1200 individuals and chip genotyping of more than 15,000 participants. Here, the effect of ACE2 variations by focusing on the receptor-binding site of SARS-CoV-2 and ACE2 cleavage by TMPRSS2 protease were investigated through simulations study. After analyzing TCGS data, 570 genetic variations on the ACE2 gene, including single nucleotide polymorphisms (SNP) and insertion/deletion (INDEL) were detected. Interestingly, two observed missense variants, K26R and S331F, which only the first one was previously reported, can reduce the receptor affinity for the viral Spike protein. Moreover, our bioinformatics simulation of 3D structures and docking of proteins explains important details of ACE2-Spike and ACE2-TMPRSS2 interactions, especially the critical role of Arg652 of ACE2 for protease function of TMPRSS2 was uncovered. As our results show that the genetic variation of ACE2 can at least influence the affinity of this receptor to its partners, we need to consider the genetic variations on ACE2 as well as other genes in the pathways that contribute to the pathogenesis of COVID-19 for designing efficient drugs and vaccines.
Striped bass (Morone saxatilis) migration timing driven by estuary outflow and sea surface temperature in the San Francisco Bay-Delta, California
Authors: Goertler Pascale , Mahardja Brian , Sommer Ted
Published: January 2021

The influence of climate on the timing of large-scale animal migrations is a major ecological and resource management concern. Anadromous fish migrations can have broad scale impacts on human communities and marine, aquatic and terrestrial food webs. However, isolating the effects of climate change on the timing of life stage transitions for anadromous fish species is challenging. Striped bass (Morone saxatilis) exhibit striking variation in migration patterns within their natural range, including migratory behaviors that change with latitude, and climate-induced temperature changes are predicted to drive future habitat and distribution changes. Here we explore the linkages between migration and multiple components of coastal and inland aquatic ecosystems impacted by climate change. By leveraging environmental and fisheries monitoring which began in 1969, we describe the upstream migration timing of non-native adult Striped bass influenced by estuary outflow and sea surface temperature in the San Francisco Bay-Delta, California. Striped bass migrated later in years when Delta outflow was greater and sea surface temperature was cooler. It is likely that temperature thresholds in the ocean during the springtime provide a cue for Striped bass to initiate migration, but sea surface temperature may also represent composite climatic trends influencing Striped bass. Further, the observed variation in migration timing of adult Striped bass has implications for predation risk on the seaward-migration of juvenile Chinook salmon.
Regulation of mitochondrial dynamics in 2-methoxyestradiol-mediated osteosarcoma cell death
Authors: Gorska-Ponikowska Magdalena , Bastian Paulina , Zauszkiewicz-Pawlak Agata , Ploska Agata , Zubrzycki Adrian , Kuban-Jankowska Alicja , Nussberger Stephan , Kalinowski Leszek , Kmiec Zbigniew
Published: January 2021

Osteosarcoma (OS) is one of the most malignant tumors of childhood and adolescence. Research on mitochondrial dynamics (fusion/fission) and biogenesis has received much attention in last few years, as they are crucial for death of cancer cells. Specifically, it was shown that increased expression of the cytoplasmic dynamin-related protein 1 (Drp1) triggers mitochondrial fission (division), which activates BAX and downstream intrinsic apoptosis, effectively inhibiting OS growth. In the presented study, human OS cells (metastatic 143B OS cell line) were incubated with 2-methoxyestradiol (2-ME) at both physiologically and pharmacologically relevant concentrations. Cell viability was determined by the MTT assay. Confocal microscopy and western blot methods were applied to examine changes in Drp1 and BAX protein levels. Mitochondrial Division Inhibitor 1, MDIVI-1, was used in the study to further examine the role of Drp1 in 2-ME-mediated mechanism of action. To determine quantitative and qualitative changes in mitochondria, electron microscopy was used. 2-ME at all used concentrations increased mitochondrial fission and induced autophagy in OS cells. At the concentration of 1 µM 2-ME increased the area density of mitochondria in OS cells. Subsequent, upregulated expression of Drp1 and BAX proteins by 2-ME strongly suggests the activation of the intrinsic apoptosis pathway. We further observed 2-ME-mediated regulation of glycolytic state of OS cells. Therefore, we suggest that changes of mitochondrial dynamics may represent a novel mechanism of anticancer action of 2-ME. This finding may open new approaches to improve the efficacy of chemotherapy in the treatment of OS, however, it has to be confirmed by in vivo studies.
A new rat model of creatine transporter deficiency reveals behavioral disorder and altered brain metabolism
Authors: Duran-Trio Lara , Fernandes-Pires Gabriella , Simicic Dunja , Grosse Jocelyn , Roux-Petronelli Clothilde , Bruce Stephen J. , Binz Pierre-Alain , Sandi Carmen , Cudalbu Cristina , Braissant Olivier
Published: January 2021

Creatine is an organic compound used as fast phosphate energy buffer to recycle ATP, important in tissues with high energy demand such as muscle or brain. Creatine is taken from the diet or endogenously synthetized by the enzymes AGAT and GAMT, and specifically taken up by the transporter SLC6A8. Deficit in the endogenous synthesis or in the transport leads to Cerebral Creatine Deficiency Syndromes (CCDS). CCDS are characterized by brain creatine deficiency, intellectual disability with severe speech delay, behavioral troubles such as attention deficits and/or autistic features, and epilepsy. Among CCDS, the X-linked creatine transporter deficiency (CTD) is the most prevalent with no efficient treatment so far. Different mouse models of CTD were generated by doing long deletions in the Slc6a8 gene showing reduced brain creatine and cognitive deficiencies or impaired motor function. We present a new knock-in (KI) rat model of CTD holding an identical point mutation found in patients with reported lack of transporter activity. KI males showed brain creatine deficiency, increased urinary creatine/creatinine ratio, cognitive deficits and autistic-like traits. The Slc6a8Y389C KI rat fairly enriches the spectrum of CTD models and provides new data about the pathology, being the first animal model of CTD carrying a point mutation.