bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermoelastic Properties of B2‐Type FeSi Under Deep Earth Conditions: Implications for the Compositions of the Ultralow‐Velocity Zones and the Inner Core
Authors: Liu Tao , Jing Zhicheng 
Published: April 2024

AbstractThe CsCl‐type (B2) phase of FeSi (B2‐FeSi) has been proposed as a candidate phase in the ultralow‐velocity zones (ULVZs) at the base of the lower mantle and in the Earth's inner core. However, the elastic properties of B2‐FeSi under relevant conditions remain unclear. Here we determine the density, elastic constants, and velocities of B2‐FeSi at high pressures (90–390 GPa) and temperatures (3,000–6,000 K) relevant to the Earth's lower most mantle and the inner core, using first‐principles molecular dynamics simulations. At the base of the lower mantle, B2‐FeSi shows significantly lower velocities and a higher density than those of the ambient mantle. Mechanical mixing models suggest the presence of ∼27–39 vol% B2‐FeSi in the silicate mantle is consistent with the reduced velocities and the elevated density of ULVZs observed seismically. On the other hand, the hcp‐Fe and B2‐FeSi mixture exhibits higher bulk sound velocity compared to the PREM under inner core conditions. Adding superionic H in the interstitial sites of B2‐FeSi lowers its density but has little effect on the bulk sound velocity of B2‐FeSi, precluding H‐bearing B2‐FeSi as a major component in the Earth's inner core.
Clusters of Compact Intracloud Discharges (CIDs) in Overshooting Convective Surges
Authors: Chen S. , Rakov V. A. , Zhu Y. , Ding Z. 
Published: April 2024

AbstractWe observed five clusters of upper‐level compact intracloud discharges (CIDs) moving positive charge up over land and over water in Florida. The clusters each contained 3 to 6 CIDs, and the overall cluster duration ranged from 27 to 58 s. On average, the CIDs in a given cluster occurred 11 s apart and were separated by a 3D distance of about 1.5 km. All the clustered CIDs were located above the tropopause and were likely associated with convective surges that penetrated the stratosphere. The average periodicity of CID occurrence within a cluster (every 11 s) was comparable to the periodicity at which the average cluster area is expected to be bombarded by ≥1016 eV cosmic‐ray particles (every 5 s). Each of such energetic particles gives rise to a cosmic ray shower (CRS) and, in the presence of sufficiently strong electric field over a sufficiently large distance, to a relativistic runaway electron avalanche (RREA). We infer that each of our upper‐level CIDs is likely to be caused by a CRS‐RREA traversing, at nearly the speed of light, the electrified overshooting convective surge and triggering, within a few microseconds, a multitude of streamer flashes along its path, over a distance of the order of hundreds of meters (as per the mechanism recently proposed for lightning initiation by Kostinskiy et al., 2020, https://doi.org/10.1029/2020JD033191). The upper‐level CID clustering was likely made possible by the recurring action of energetic cosmic rays and the rapid recovery of the negative screening charge layer at stratospheric altitudes.
Thermoelastic Properties and Thermal Evolution of the Martian Core From Ab Initio Calculated Magnetic Fe‐S Liquid
Authors: Li Wei‐Jie , Li Zi , Ma Zhe , Zhou Jie , Wang Cong , Zhang Ping 
Published: April 2024

AbstractAccurate thermoelastic properties and thermal conductivity are crucial for understanding the thermal evolution of the Martian core. A fitting method based on ab initio calculated pressure‐volume‐temperature data was proposed for the formulation of the equation of state with high accuracy, by which the pressure and temperature dependent thermoelastic properties can be directly calculated by definitions. Ab initio results showed that Fe0.75S0.25 liquid under Martian core conditions was thoroughly in a magnetic state without existing spin crossover. The Fe0.75S0.25 liquid in magnetic calculations had a low thermal conductivity (21–23 W/m/K) when compared with non‐magnetic calculations at the same state. Based on Insight's estimated Martian core properties (Stähler et al., 2021, https://doi.org/10.1126/science.abi7730) and ab initio calculated properties of the Fe0.75S0.25 liquid, the scenario for the thermal evolution of the Martian core is the iron‐snow model crystallization regime. The parameter uncertainty effect on the cessation time of the dynamo and zone of iron snow was systematically analyzed.
The Coprecipitation of Akaganeite and Jarosite and Its Implications for the Late‐Stage Diagenetic Fluids in the Vera Rubin Ridge, Gale Crater, Mars
Authors: Zhang Lingxi , Fu Xiaohui , Ling Zongcheng , Shi Erbin , Cao Haijun 
Published: April 2024

AbstractAkaganeite and jarosite were detected in two mudstone drill samples from Vera Rubin ridge (VRR), Gale crater by Chemistry & Mineralogy X‐Ray Diffraction (CheMin). The co‐occurrence of these two minerals is quite rare in both terrestrial and Martian aqueous environments. In order to confine the chemical conditions of paragenetic akaganeite and jarosite, and provide insight into late‐stage diagenetic alterations at VRR, we synthesized akaganeite and jarosite with varying SO42− concentrations and initial pH levels. Synthetic samples were characterized using Field Emission Scanning Electron Microscopy, X‐ray powder diffraction and Raman spectroscopy. Our study reveals that akaganeite and jarosite exist in equilibrium in the solution with 0.011–0.028 M SO42− with respect to 0.6 M Cl− and an initial pH of 1.3–2.2. In combination with the CheMin detection results, the chemistry and pH values of the fluids at VRR can be further constrained. Considering the absence of goethite and the relative higher portion of akaganeite than jarosite in the drill samples, the pH values should be 1.4–2 and the S/Cl molar ratio should be within the range of 0.018–0.042. Based on our laboratory results, we hypothesize that the presence of akaganeite and jarosite at VRR represents an individual episode of acidic groundwater activity. During the late‐stage diagenetic process at VRR, upwelled acidic groundwater dissolved the local chlorides to form the Cl−‐dominated fluids. Subsequent evaporation further concentrated the acid saline fluids and therefore resulted in an extremely acidic environment (1.4 ≤ pH＜2 with S/Cl molar ratio of 0.018–0.042), which produced akaganeite and jarosite.
Retrieval of Ar, N2, O, and CO in the Martian Thermosphere Using Dayglow Limb Observations by EMM EMUS
Authors: Evans J. S. , Deighan J. , Jain S. , Veibell V. , Correira J. , Al Matroushi H. , Al Mazmi H. , Chaffin M. , Curry S. , El‐Kork N. , England S. , Eparvier F. , Fillingim M. , Holsclaw G. , Khalil M. , Lillis R. , Lootah F. , Mahmoud S. , Plummer T. , Soto E. , Tennyson J. , Thiemann E. , Yurchenko S. N. 
Published: April 2024

AbstractThe Emirates Ultraviolet Spectrometer (EMUS) onboard the Emirates Mars Mission (EMM) Hope probe images Mars at wavelengths extending from approximately 100 to 170 nm. EMUS observations began in February 2021 and cover over a full Mars year. We report the first limb scan observations at Mars of ultraviolet emissions Ar I 106.6 nm, N I 120 nm, and carbon monoxide (CO) Fourth Positive Group (A − X) band system excited by electron impact on CO. We use EMUS limb scan observations to retrieve number density profiles of argon, molecular nitrogen, atomic oxygen, and CO in the upper atmosphere of Mars from 130 to 160 km. CO is a sensitive tracer of the thermal profile and winds in Mars' middle atmosphere and the chemistry that balances CO2 in the atmosphere of Mars. EMUS insertion orbit special observations demonstrate that far ultraviolet limb measurements of the Martian thermosphere can be spectroscopically analyzed with a robust retrieval algorithm to further quantify variations of CO composition in the Martian upper atmosphere.
High Basal Melt Rates and High Strain Rates Lead to More Fractured Ice
Authors: Watkins Ray H. , Bassis Jeremy N. , Thouless M. D. , Luckman Adrian 
Published: April 2024

AbstractIce shelves limit the flux of grounded ice into the ocean by buttressing the discharge of land‐based ice upstream. Ice shelf weakening and collapse can lead to decreased buttressing and observations increasingly show that some ice shelves have experienced increased melt and increased calving, with recent hypotheses suggesting that increased melt leads to increased fracturing. However, the specific processes that control this correlation are not yet understood, with mechanisms other than melt affecting fracturing. Here we use the topography of the ice shelf base from BedMachine to investigate how basal melting and ice deformation contribute to crevasse and melt channel formation and evolution on the Pine Island Ice Shelf in West Antarctica. We find that high basal melt rates and high first principal strain rates lead to substantial roughening of the ice shelf through a collection of features, including melt channels and crevasses. Critically, melt channels and crevasses are the deepest in all directions at locations where the highest rates of melting and straining occur simultaneously. This suggests that the combination of melt rates and strain rates work in tandem to excavate and seed the deepest melt channels and crevasses on ice shelves. These features then may form lines of weakness that transform into rifts and, ultimately, the detachment boundary for calving events. This implies that melt and fracture play an important role in controlling the dynamics of ice shelves.
Characterizing Subglacial Hydrology Within the Amery Ice Shelf Catchment Using Numerical Modeling and Satellite Altimetry
Authors: Wearing Martin G. , Dow Christine F. , Goldberg Daniel N. , Gourmelen Noel , Hogg Anna E. , Jakob Livia 
Published: April 2024

AbstractMeltwater forms at the base of the Antarctic Ice Sheet due to geothermal heat flux (GHF) and basal frictional dissipation. Despite the relatively small volume, this water has a profound effect on ice‐sheet dynamics. However, subglacial melting and hydrology in Antarctica remain highly uncertain, limiting our ability to assess their impact on ice‐sheet dynamics. Here we examine subglacial hydrology within the Amery Ice Shelf catchment, East Antarctica, using the subglacial hydrology model GlaDS. We calculate subglacial melt rates using a higher‐order ice‐flow model and two GHF estimates. We find a catchment‐wide melt rate of 7.03 Gt year−1 (standard deviation = 1.94 Gt year−1), which is ≥50% greater than previous estimates. The contribution from basal dissipation is approximately 40% of that from GHF. However, beneath fast‐flowing ice streams, basal dissipation is an order of magnitude larger than GHF, leading to a significant increase in channelized subglacial flux upstream of the grounding line. We validate GlaDS using high‐resolution interferometric‐swath radar altimetry, with which we detect active subglacial lakes and fine‐scale ice‐shelf basal melting. We find a network of subglacial channels that connects areas of deep subglacial water coincident with active subglacial lakes, and channelized discharge at the grounding line coinciding with enhanced ice‐shelf basal melting. The concentrated discharge of meltwater provides 36% of the freshwater released into the ice‐shelf cavity, in addition to ice‐shelf basal melting. This suggests that ice‐shelf basal melting is strongly influenced by subglacial hydrology and could be affected by future changes in subglacial discharge, such as lake drainage or channel rerouting.
1.44 Ga Oxygenation Event: Evidence From the Southern Margin of North China
Authors: Yang Hongying , Shi Xiaoying , Xu Lei , Sun Longfei , Xie Baozeng , Zhou Limin , Huang Kangjun , Zhou Xiqiang , Tang Dongjie 
Published: April 2024

AbstractPrevious studies suggest that the atmospheric and shallow seawater oxygen levels during the mid‐Proterozoic may have remained persistently unbalanced due to the low atmospheric oxygen levels and that, under these conditions, the oxygen concentrations of shallow seawater would largely reflect local oxygenation caused by primary productivity. As a result, in a microbialite‐rich setting, it may be difficult to differentiate oxygenation caused by local primary productivity from overall oxygenation of the surface environment. To address this issue, we conducted an integrative study of the ∼1.44 Ga stromatolitic carbonates of the Fengjiawan Formation in the Xiong’er Basin, southern North China, using techniques of sedimentology, mineralogy and geochemistry. The results show that the Fengjiawan Formation is dominated by water‐column precipitated carbonate mud (now dolomitized), pointing to moderately oxidized marine conditions. A significant and stable negative Cerium (Ce) anomaly (as low as 0.42) is identified in a long interval (>50 m in thickness) of this formation. This Ce anomaly is lower than the minimum values both recorded in the Great Oxidation Event (GOE; minimum 0.76) and in the Neoproterozoic Oxygenation Event (NOE; minimum 0.52), suggesting a significant oxygenation process rather than an oxygen oasis. Some intervals in this formation show I/(Ca + Mg) values higher than the Precambrian background value of 0.5 μmol/mol, providing a further support for shallow seawater oxygenation. This study, together with the enhanced oxygenation identified in the time‐equivalent Tieling Formation, indicates a multi‐basin oxygenation event in North China at ∼1.44 Ga.
Trends and Interannual Variability of the Hydroxyl Radical in the Remote Tropics During Boreal Autumn Inferred From Satellite Proxy Data
Authors: Anderson Daniel C. , Duncan Bryan N. , Liu Junhua , Nicely Julie M. , Strode Sarah A. , Follette‐Cook Melanie B. , Souri Amir H. , Ziemke Jerry R. , González‐Abad Gonzalo , Ayazpour Zolal 
Published: April 2024

AbstractDespite its importance for the global oxidative capacity, spatially resolved trends and variability of the hydroxyl radical (OH) are poorly constrained. We demonstrate the utility of a tropospheric column OH (TCOH) product, created from machine learning and satellite proxy data, in determining the spatial variability in trends of tropical OH over the oceans during September through November. While OH increases domain‐wide by 2.1%/decade from 2005–2019, we find significant spatial heterogeneity in regional trends, with decreases in some areas of 2.5%/decade. Our analysis of the trends in the proxy data indicate anthropogenic‐driven changes in emissions of OH drivers as well as increasing temperatures cause these trends. This OH product is potentially a significant advance in constraining OH spatial variability and serves as a useful complement to existing tools in understanding the atmospheric oxidative capacity. Comprehensive observations of TCOH are required to assess the fidelity of this method.
An ancestral SARS-CoV-2 vaccine induces anti-Omicron variants antibodies by hypermutation
Authors: Park Seoryeong , Choi Jaewon , Lee Yonghee , Noh Jinsung , Kim Namphil , Lee JinAh , Cho Geummi , Kim Sujeong , Yoo Duck Kyun , Kang Chang Kyung , Choe Pyoeng Gyun , Kim Nam Joong , Park Wan Beom , Kim Seungtaek , Oh Myoung-don , Kwon Sunghoon , Chung Junho 
Published: April 2024

AbstractThe immune escape of Omicron variants significantly subsides by the third dose of an mRNA vaccine. However, it is unclear how Omicron variant-neutralizing antibodies develop under repeated vaccination. We analyze blood samples from 41 BNT162b2 vaccinees following the course of three injections and analyze their B-cell receptor (BCR) repertoires at six time points in total. The concomitant reactivity to both ancestral and Omicron receptor-binding domain (RBD) is achieved by a limited number of BCR clonotypes depending on the accumulation of somatic hypermutation (SHM) after the third dose. Our findings suggest that SHM accumulation in the BCR space to broaden its specificity for unseen antigens is a counterprotective mechanism against virus variant immune escape.
Long-term dataset for contaminants in fish, mussels, and bird eggs from the Baltic Sea
Authors: Ammar Yosr , Faxneld Suzanne , Sköld Martin , Soerensen Anne L. 
Published: April 2024

AbstractWidespread persistent contaminants are a global environmental problem. In the Baltic Sea, wildlife contamination was first noticed in the 1960s, prompting the Swedish Environmental Protection Agency to establish a comprehensive Swedish National Monitoring Programme for Contaminants in Marine Biota (MCoM) in 1978 run by the Swedish Museum of Natural History. Eight species have been analysed, four fish species (Atlantic herring, Atlantic cod, European perch, viviparous eelpout), one bivalve species (blue mussel), and egg from three bird species (common guillemot, common tern, Eurasian oystercatcher). Here, we present a dataset containing MCoM data from its start until 2021. It includes 36 sets of time-series, each analysed for more than 100 contaminants. The longest time-series is for common guillemot and starts in 1968. We describe the structure of MCoM including historic changes to the number of stations, sample treatment, analytical methods, instruments, and laboratories. The MCoM data is available at the Bolin Centre repository and on GitHub through our R package mcomDb. The latter will be updated yearly with new MCoM records.
Bias-corrected NESM3 global dataset for dynamical downscaling under 1.5 °C and 2 °C global warming scenarios
Authors: Zhang Meng-Zhuo , Han Ying , Xu Zhongfeng , Guo Weidong 
Published: April 2024

AbstractDynamical downscaling is vital for generating finer-scale climate projections. Recently, a set of simulations under four types of 1.5/2 °C global warming scenarios are available with Nanjing University of Information Science and Technology Earth System Model (NESM). However, NESM3’s bias in large-scale driving variables would degrade downscaled simulations. We corrected NESM3 bias in terms of climate mean and inter-annual variance against ERA5 using a novel bias correction method and then produced a set of bias-corrected datasets for dynamical downscaling. The bias-corrected NESM3 spans the historical period for 1979–2014 and four future scenarios (i.e., 1.5 °C overshoot for 2070–2100, stabilized 1.5/2 °C for 2070–2100, and transient 2 °C for 2031–2061) with 1.25° × 1.25° horizontal resolution at six-hourly intervals. Our evaluation suggests that bias-corrected NESM3 outperforms the original NESM3 in the climatological mean of seasonal mean and variability, as well as climate extreme events during the historical period. This bias-corrected dataset is expected to generate more reliable projections for regional climate and environment under 1.5/2 °C global warming.
Effective adsorption of fluorescent congo red azo dye from aqueous solution by green synthesized nanosphere ZnO/CuO composite using propolis as bee byproduct extract
Authors: Radwan Ahmed , Mohamed Samir O. , Khalil Mostafa M. H. , El-Sewify Islam M. 
Published: April 2024

AbstractThe indirect dumping of massive volumes of toxic dyes into water has seriously affected the ecosystem. Owing to the many applications of the designed nanomaterials in the manufacturing process, there is a lot of research interest in synthesizing nanomaterials using green processes. In this research, the byproduct of bee was employed to synthesize nanoparticles (NPs) of ZnO, CuO, and biosynthesized ZnO/CuO (BZC) nanocomposite via utilizing a green and simple approach. To validate the effective fabrication of BZC nanocomposite, various characterization measurements were applied. FTIR analysis identified the functional groups in charge of producing nanoparticles and nanocomposites. Moreover, the existence of ZnO and CuO XRD peaks suggests that the nanocomposites were successfully biosynthesized. The high-resolution XPS spectrum of the BZC nanocomposite’s Zn2p3, Cu2p3, and O1s were observed. Our findings indicate the successful engineering of the prepared nanomaterials and BZC nanocomposite. Our findings indicate the successful engineering of the prepared nanomaterials and BZC nanocomposite. For Congo red (CR) fluorescent stain azo dye elimination in water, all adsorption parameters were examined at room temperature. Moreover, the adsorption experiments revealed the removal capacity for uptake CR dye using BZC nanocomposite (90.14 mg g−1). Our results show that the BZC nanocomposite exhibited high removal capability for the adsorption of CR dye. The nanosphere adsorbent offered a simple, low-cost, and green approach for water purification and industrial wastewater control.
A novel method-based reinforcement learning with deep temporal difference network for flexible double shop scheduling problem
Authors: Wang Xiao , Zhong Peisi , Liu Mei , Zhang Chao , Yang Shihao 
Published: April 2024

AbstractThis paper studies the flexible double shop scheduling problem (FDSSP) that considers simultaneously job shop and assembly shop. It brings about the problem of scheduling association of the related tasks. To this end, a reinforcement learning algorithm with a deep temporal difference network is proposed to minimize the makespan. Firstly, the FDSSP is defined as the mathematical model of the flexible job-shop scheduling problem joined to the assembly constraint level. It is translated into a Markov decision process that directly selects behavioral strategies according to historical machining state data. Secondly, the proposed ten generic state features are input into the deep neural network model to fit the state value function. Similarly, eight simple constructive heuristics are used as candidate actions for scheduling decisions. From the greedy mechanism, optimally combined actions of all machines are obtained for each decision step. Finally, a deep temporal difference reinforcement learning framework is established, and a large number of comparative experiments are designed to analyze the basic performance of this algorithm. The results showed that the proposed algorithm was better than most other methods, which contributed to solving the practical production problem of the manufacturing industry.
Protein characteristics substantially influence the propensity of activity cliffs among kinase inhibitors
Authors: Daoud Safa , Taha Mutasem 
Published: April 2024

AbstractActivity cliffs (ACs) are pairs of structurally similar molecules with significantly different affinities for a biotarget, posing a challenge in computer-assisted drug discovery. This study focuses on protein kinases, significant therapeutic targets, with some exhibiting ACs while others do not despite numerous inhibitors. The hypothesis that the presence of ACs is dependent on the target protein and its complete structural context is explored. Machine learning models were developed to link protein properties to ACs, revealing specific tripeptide sequences and overall protein properties as critical factors in ACs occurrence. The study highlights the importance of considering the entire protein matrix rather than just the binding site in understanding ACs. This research provides valuable insights for drug discovery and design, paving the way for addressing ACs-related challenges in modern computational approaches.