bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Concrete Security of LWE With Small Secret
Authors: Chua Lynn , Chen Hao , Song Yongsoo , Lauter Kristin 
Published: June 2024

AbstractLattice-based cryptography is currently under consideration for standardization in the ongoing NIST PQC Post-Quantum Cryptography competition, and is used as the basis for Homomorphic Encryption schemes world-wide. Both applications rely specifically on the hardness of the Learning With Errors (LWE) problem. Most Homomorphic Encryption deployments use small secrets as an optimization, so it is important to understand the concrete security of LWE when sampling the secret from a non-uniform, small distribution. Although there are numerous heuristics used to estimate the running time and quality of lattice reduction algorithms such as BKZ2.0, more work is needed to validate and test these heuristics in practice to provide concrete security parameter recommendations, especially in the case of small secret. In this work, we introduce a new approach which uses concrete attacks on the LWE problem as a way to study the performance and quality of BKZ2.0 directly. We find that the security levels for certain values of the modulus q and dimension n are smaller than predicted by the online Lattice Estimator, due to the fact that the attacks succeed on these uSVP lattices for blocksizes which are smaller than expected based on current estimates. We also find that many instances of the TU Darmstadt LWE challenges can be solved significantly faster when the secret is chosen from the binary or ternary distributions.
Dynamical chiral Nernst effect in twisted Van der Waals few layers
Authors: Li Juncheng , Zhai Dawei , Xiao Cong , Yao Wang 
Published: June 2024

AbstractThe Nernst effect is a fundamental thermoelectric conversion phenomenon that was deemed to be possible only in systems with magnetic field or magnetization. In this work, we propose a novel dynamical chiral Nernst effect that can appear in two-dimensional van der Waals materials with chiral structural symmetry in the absence of any magnetic degree of freedom. This unconventional effect is triggered by time variation of an out-of-plane electric field, and has an intrinsic quantum geometric origin linked to not only the intralayer center-of-mass motion but also the interlayer coherence of electronic states. We demonstrate the effect in twisted homobilayer and homotrilayer transition metal dichalcogenides, where the strong twisted interlayer coupling leads to sizable intrinsic Nernst conductivities well within the experimental capacity. This work suggests a new route for electric control of thermoelectric conversion.
Comment on “Stratospheric Aerosol Composition Observed by the Atmospheric Chemistry Experiment Following the 2019 Raikoke Eruption” by Boone et al.
Authors: Ansmann Albert , Veselovskii Igor , Ohneiser Kevin , Chudnovsky Alexandra 
Published: June 2024

AbstractBased on satellite observations in the Arctic stratosphere at latitudes from 61° to 66°N in the second half of 2019, Boone et al. (2022, https://doi.org/10.1029/2022jd036600) provide the impression that the aerosol in the upper troposphere and lower stratosphere (UTLS) over the entire Arctic consisted of sulfate aerosol originating from the Raikoke volcanic eruption in the summer of 2019. Here, we show that this was most probably not the case and the aerosol layering conditions were much more complex. By combining the stratospheric aerosol typing results of Boone et al. (2022, https://doi.org/10.1029/2022jd036600) with lidar observations at 85°–86°N of Ohneiser et al. (2021, https://doi.org/10.5194/acp‐21‐15783‐2021) of a dominating wildfire smoke layer in the UTLS height range, we demonstrate that the Arctic UTLS aerosol most likely consisted of Siberian wildfire smoke in the lower part and sulfate aerosol in the upper part of the aerosol layer which extended from 7 to 19 km height and was well observable until May 2020. The smoke‐ and sulfate‐related aerosol optical thickness (AOT) fractions were about 0.7–0.8 and 0.2–0.3, respectively, according to our analysis. The sulfate AOT is in good agreement with model‐based predictions of the Raikoke sulfate AOT.
Nowcasting Earthquakes With Stochastic Simulations: Information Entropy of Earthquake Catalogs
Authors: Rundle John B. , Baughman Ian , Zhang Tianjian 
Published: June 2024

AbstractEarthquake nowcasting has been proposed as a means of tracking the change in large earthquake potential in a seismically active area. The method was developed using observable seismic data, in which probabilities of future large earthquakes can be computed using Receiver Operating Characteristic methods. Furthermore, analysis of the Shannon information content of the earthquake catalogs has been used to show that there is information contained in the catalogs, and that it can vary in time. So an important question remains, where does the information originate? In this paper, we examine this question using stochastic simulations of earthquake catalogs. Our catalog simulations are computed using an Earthquake Rescaled Aftershock Seismicity (“ERAS”) stochastic model. This model is similar in many ways to other stochastic seismicity simulations, but has the advantage that the model has only 2 free parameters to be set, one for the aftershock (Omori‐Utsu) time decay, and one for the aftershock spatial migration away from the epicenter. Generating a simulation catalog and fitting the two parameters to the observed catalog such as California takes only a few minutes of wall clock time. While clustering can arise from random, Poisson statistics, we show that significant information in the simulation catalogs arises from the “non‐Poisson” power‐law aftershock clustering, implying that the practice of de‐clustering observed catalogs may remove information that would otherwise be useful in forecasting and nowcasting. We also show that the nowcasting method provides similar results with the ERAS model as it does with observed seismicity.
Uncertain Pathways to a Future Safe Climate
Authors: Sherwood S. C. , Hegerl G. , Braconnot P. , Friedlingstein P. , Goelzer H. , Harris N. R. P. , Holland E. , Kim H. , Mitchell M. , Naish T. , Nobre P. , Otto‐Bliesner B. L. , Reed K. A. , Renwick J. , van der Wel N. P. M. 
Published: June 2024

AbstractGlobal climate change is often thought of as a steady and approximately predictable physical response to increasing forcings, which then requires commensurate adaptation. But adaptation has practical, cultural and biological limits, and climate change may pose unanticipated global hazards, sudden changes or other surprises–as may societal adaptation and mitigation responses. These poorly known factors could substantially affect the urgency of mitigation as well as adaptation decisions. We outline a strategy for better accommodating these challenges by making climate science more integrative, in order to identify and quantify known and novel physical risks including those arising from interactions with ecosystems and society. We need to do this even–or especially–when they are highly uncertain, and to explore risks and opportunities associated with mitigation and adaptation responses by engaging across disciplines. We argue that upcoming climate assessments need to be more risk‐aware, and suggest ways of achieving this. These strategies improve the chances of anticipating potential surprises and identifying and communicating “safe landing” pathways that meet UN Sustainable Development Goals and guide humanity toward a better future.
Knowledge Gaps in Quantifying the Climate Change Response of Biological Storage of Carbon in the Ocean
Authors: Henson Stephanie , Baker Chelsey A. , Halloran Paul , McQuatters‐Gollop Abigail , Painter Stuart , Planchat Alban , Tagliabue Alessandro 
Published: June 2024

AbstractThe ocean is responsible for taking up approximately 25% of anthropogenic CO2 emissions and stores >50 times more carbon than the atmosphere. Biological processes in the ocean play a key role, maintaining atmospheric CO2 levels approximately 200 ppm lower than they would otherwise be. The ocean's ability to take up and store CO2 is sensitive to climate change, however the key biological processes that contribute to ocean carbon storage are uncertain, as are how those processes will respond to, and feedback on, climate change. As a result, biogeochemical models vary widely in their representation of relevant processes, driving large uncertainties in the projections of future ocean carbon storage. This review identifies key biological processes that affect how ocean carbon storage may change in the future in three thematic areas: biological contributions to alkalinity, net primary production, and interior respiration. We undertook a review of the existing literature to identify processes with high importance in influencing the future biologically‐mediated storage of carbon in the ocean, and prioritized processes on the basis of both an expert assessment and a community survey. Highly ranked processes in both the expert assessment and survey were: for alkalinity—high level understanding of calcium carbonate production; for primary production—resource limitation of growth, zooplankton processes and phytoplankton loss processes; for respiration—microbial solubilization, particle characteristics and particle type. The analysis presented here is designed to support future field or laboratory experiments targeting new process understanding, and modeling efforts aimed at undertaking biogeochemical model development.
Non‐Linear Vertical Land Motion of Coastal Chile and the Antarctic Peninsula Inferred From Combining Satellite Altimetry, Tide Gauge and GPS Data
Authors: Rezvani Mohammad‐Hadi , Watson Christopher S. , King Matt A. 
Published: June 2024

AbstractWe developed an enhanced Kalman‐based approach to quantify abrupt changes and significant non‐linearity in vertical land motion (VLM) along the coast of Chile and the Antarctic Peninsula using a combination of multi‐mission satellite altimetry (ALT), tide gauge (TG), and GPS data starting from the early 1990s. The data reveal the spatial variability of co‐seismic and post‐seismic subsidence at TGs along the Chilean subduction zone in response to the Mw8.8 Maule 2010, Mw8.1 Iquique 2014, and Mw8.3 Illapel 2015 earthquakes that are not retrievable from the interpolation of sparse GPS observations across space and time. In the Antarctic Peninsula, where continuous GPS data do not commence until ∼1998, the approach provides new insight into the ∼2002 change in VLM at the TGs of +5.3 ± 2.2 mm/yr (Palmer) and +3.5 ± 2.8 mm/yr (Vernadsky) due to the onset of ice‐mass loss following the Larsen‐B Ice Shelf breakup. We used these data to constrain viscoelastic Earth model parameters for the northern Antarctic Peninsula, obtaining a preferred lithosphere thickness of 115 km and upper mantle viscosity of 0.9 × 1018 Pa s. Our estimates of regionally‐correlated ALT systematic errors are small, typically between ∼±0.5–2.5 mm/yr over single‐mission time scales. These are consistent with competing orbit differences and the relative errors apparent in ALT crossovers. This study demonstrates that, with careful tuning, the ALT‐TG technique can provide improved temporal and spatial sampling of VLM, yielding new constraints on geodynamic models and assisting sea‐level change studies in otherwise data sparse regions and periods.
Discriminating Lithospheric and Asthenospheric Anisotropy Beneath Northern Oman: Sharp Contrast Observed at the Semail Gap Fault Zone
Authors: Komeazi A. , Kaviani A. , Rümpker G. , Weidle C. , Meier T. 
Published: June 2024

AbstractTo gain a deeper understanding of the extensive and varied lithospheric deformations beneath northern Oman, we examine seismic anisotropy in this region using splitting analysis of teleseismic shear wave data. Our study utilizes data from a dense network consisting of 13 permanent and 45 temporary seismic stations, which were operational for approximately 2.5 years starting from October 2013. By examining the azimuthal distribution of shear wave splitting (SWS) parameters, we were able to divide the study area into three sub‐regions. The stations located to the west of the Hawasina window exhibit relatively azimuthally invariant SWS parameters suggesting a single anisotropic layer. On the other hand, most of the stations located in the central and eastern regions display variations versus back‐azimuth, indicating the potential presence of depth‐dependent anisotropy. The General NW‐SE trend of the Fast Polarization Directions (FPDs) of the one‐layer anisotropy in the west and FPDs of the upper layers in the east is concordant with the strike of the structures resulting from the collision between the continental and oceanic plates. A clear contrast in SWS parameters is observed in the Semail Gap Fault Zone (SGFZ), suggesting that the SGFZ can be a lithospheric‐scale structure that hampers the intrusion of mafic magma from the southeast. Furthermore, the FPDs of the lower layer in the east exhibit an NE‐SW trend, which may be indicative of the large‐scale mantle flow resulting from the present‐day plate motion.
Integrated Effects of Site Hydrology and Vegetation on Exchange Fluxes and Nutrient Cycling at a Coastal Terrestrial‐Aquatic Interface
Authors: Li Bing , Li Zhi , Zheng Jianqiu , Jiang Peishi , Holmquist James , Regier Peter J. , Hammond Glenn E. , Ward Nicholas D. , Myers‐Pigg Allison , Rich Roy , Huang Wei , O’Meara Theresa A. , Pennington Stephanie C. , Megonigal Patrick , Bailey Vanessa L. , Chen Xingyuan 
Published: June 2024

AbstractThe complex interactions among soil, vegetation, and site hydrologic conditions driven by precipitation and tidal cycles control the biogeochemical transformations and bi‐directional exchange of carbon and nutrients across the terrestrial–aquatic interfaces (TAIs) in coastal regions. This study uses a highly mechanistic model, Advanced Terrestrial Simulator (ATS)‐PFLOTRAN, to explore how these interactions affect exchanges of materials and carbon and nitrogen cycling. We used a transect in the Chesapeake Bay region that spans zones of open water, coastal wetland, transition, and upland forest. We designed several simulation scenarios to parse the effects of the individual controlling factors and the sensitivity of carbon cycling to reaction rate parameters derived from laboratory experiments. Our simulations reveal an active zone for carbon cycling under the transition zones between the wetland and the upland. Evapotranspiration is found to enhance the exchange fluxes between the surface and subsurface domains, resulting in a higher dissolved oxygen concentration in the TAIs. The transport of organic carbon derived from plant leaves and roots provide an additional source of organic carbon needed for the aerobic respiration and denitrification processes in the TAIs. The variability in reaction rate parameters associated with microbial activities is also found to play a dominant role in controlling the heterogeneity and dynamics of the simulated redox conditions. This modeling‐focused exploratory study enabled us to better understand the complex interactions among soil, water and microbes that govern the hydro‐biogeochemical processes at the TAIs, which is an important step toward representing coastal ecosystems in larger‐scale Earth system models.
On the Sensitivity of Future Hydrology in the Colorado River to the Selection of the Precipitation Partitioning Method
Authors: Wang Zhaocheng , Vivoni Enrique R. , Whitney Kristen M. , Xiao Mu , Mascaro Giuseppe 
Published: June 2024

AbstractThe accurate partitioning of precipitation is important for snowpack and streamflow simulations in mountainous regions. However, most hydrologic models employ a partitioning method based on near‐surface air temperature (Ta) and the sensitivity of hydrologic simulations to the selection of the precipitation partitioning method (PPM) under climate change has been underexplored. To address this, we compared simulations using two PPMs, a conventional Ta‐based scheme and a wet‐bulb temperature (Tw)‐based approach (TA and TW) with the Variable Infiltration Capacity model. Our study focused on the Colorado River Basin (CRB) which is vulnerable to future snowfall and streamflow reductions due to climate warming. Historical simulations demonstrated the improved performance of the TW scheme in simulating snowfall fraction (SF) and snow water equivalent (SWE) in relation to in situ observations and a gridded SWE product. Subsequently, we evaluated the influence of the PPM selection on snowpack and streamflow projections from eight climate models under two emissions scenarios. The ensemble median results revealed more substantial decline in annual SF with the TW scheme as compared to the TA method (−12% vs. −9%) from the historical (1976–2005) to the far future (2066–2095) period, especially at lower elevations. Hydrologic simulations showed that the TA scheme underestimated reductions in SWE and streamflow (Q) under warming as compared to the TW scheme. This finding has important implications on future projections for the CRB and in other mountainous basins where climate warming can shift conditions from snowfall to rainfall.
The Impact of Clay and Fluid Conductivity on the Electrical‐Diffusion Tortuosity Correlations in Sandstone Reservoirs
Authors: Elsayed Mahmoud , El‐Husseiny Ammar , Kwak Hyung , Adebayo Abdulrauf R. , Mahmoud Mohamed 
Published: June 2024

AbstractTortuosity has different definitions that are used by scientists and engineers to describe various fluid‐related processes in porous media. Two of the most commonly used definitions are electrical (describing the electrical current flow process) and diffusion (related to the molecular diffusive flow process) tortuosity. In this study, we investigate the impact of minerology (presence of clay) and fluid conductivity on the electrical‐diffusion tortuosity relationship. That is: whether or not electrical and diffusion tortuosity have one‐to‐one relationship in sandstones. Two groups of samples were used: clean Fontainebleau sandstones and clayey sandstones. Electrical resistivity was measured using four‐electrode method to obtain electrical formation factor and calculate the electrical tortuosity (τe) using a model that is applicable for consolidated rocks. Pulsed field gradient nuclear magnetic resonance (PFG NMR) measurements were employed to quantify diffusion tortuosity (τD). At lower fluid conductivity (3 S/m), our results show that τD ≈τe for clean sandstones, while τe << τD is observed for clayey sandstones. We propose that mineralogy has direct impact on the τe−τD relationship: the presence of clay minerals added surface conductivity which contributed to underestimating the intrinsic formation factor (F′) and consequently reducing τe. As the fluid conductivity increases, τe converges to τD until reaching the high salinity limit at which F′ is obtained and τD becomes in good agreement with τe for the clayey sandstone. The NMR diffusion approach presented here shows the potential of estimating F′ without the need for multi‐salinity data which can contribute to improved permeability prediction.
The Janus‐Faced Role of Renewable Energy Development in Global Carbon Reduction Under Renewable Energy Policies
Authors: Chen Yang , Hong Jingke , Wen Quan , Yi Wen , Zheng Saina 
Published: June 2024

AbstractThe global‐scale empirical analysis of how renewable energy policies (REPs) affect carbon emissions and the mediating role of renewable energy development (RED) in this mechanism remains underexplored. To fill this research gap, we extracted and organized REPs data from IEA's databases for 135 countries until 2018 and conducted empirical analyses of these issues. We find that: (a) REPs significantly reduce global carbon emissions, especially through regulatory, economic, and R&D policies. (b) REPs' effectiveness in mitigating carbon emissions is enhanced by robust energy infrastructure, strong control of corruption, and adherence to the rule of law. Besides, the balance of REPs types does not influence their efficiency, but REPs prioritizing certain renewable energy (RE) types aligns better with carbon reduction goals. (c) RED displays a Janus‐faced influence on REPs' carbon reduction effect—renewable energy consumption (REC) positively mediates it, whereas renewable energy share (RES) exerts a negative mediation. Specifically, REC consistently reduces carbon emissions, while RES initially increases and then decreases carbon emissions, exhibiting an inverted U‐shape. (d) The initial rise in carbon emissions with RES is due to the low substitution of RE for fossil energy and the country‐specific heterogeneity in organizational, geographic, industrial, economic, demographic, and temporal factors.
Earthquake Seismicity Reveals the Location and Significance of the Shona Mantle Plume in the South Atlantic Ocean
Authors: Parnell‐Turner Ross 
Published: June 2024

AbstractThe South Atlantic Ocean hosts several well‐studied volcanic ridges and seamount chains, but the origin of their associated mantle plumes is debated. Reduced seismicity on the southern Mid‐Atlantic Ridge (MAR) suggests anomalously ductile thermomechanical conditions at 52°S and 47.5°S. These low seismicity patches extend 120–560 km along‐axis, and correspond with axial high spreading ridge morphology, geochemical anomalies, and mantle wave speed patterns likely associated with the Shona and Discovery plumes. Bathymetric data show that the northern extent of the Shona swell is associated with increased volcanism, elevated axial bathymetry, and a series of northward‐propagating rifts, with the overall swell geometry suggesting a buoyancy flux of 0.4–0.5 Mg s−1. The nearby Bouvet Island may be a product of a branch of the larger Shona plume swell, which has influenced crustal accretion on the southern MAR for the past 24 million years.
Rapid Relativistic Electron Enhancements During Van Allen Probes Era
Authors: Xiong Senlin , Dai Lei , Wang Xu , Wang Chi 
Published: June 2024

AbstractRelativistic electron fluxes in the outer radiation belt exhibit significant variability during geomagnetic storms and substorms. This study investigates rapid relativistic electron enhancements (REE) in the outer radiation belt throughout the entire Van Allen Probes (RBSP) era from October 2012 to October 2019. Utilizing RBSP measurements, we identify 182 rapid REE events characterized by a factor of greater than two increase in relativistic electron fluxes within a half RBSP orbit (approximately 4.5 hr) at L = 4.5–5.5. Approximately 76% of rapid REE events occur during geomagnetic storms. Rapid REEs during storms are concentrated within the 12‐hr period preceding and the 24‐hr period following the end of the storm's main phase. Intense REE are more likely found in storm's main phase compared to moderate REE. Sub‐relativistic and relativistic electron injections are commonly observed during rapid REE. Substorm activities (AL/AE, MPB index) and convection (AU index) are more intense before and during REE, in contrast to the intervals following REEs. The intensity of rapid REE correlates with the strength of substorms and convection. This comprehensive survey suggests that rapid REEs in the outer radiation belt are likely associated with, but not strictly tied to, geomagnetic storms. Enhanced convection and substorm appear to create favorable conditions for rapid REE. These substorms and enhanced convection are likely linked to favorable solar wind conditions for REEs, as documented in previous studies.