bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanisms of Reappeared Period Shifts of Internal Solitary Waves Based on Mooring Array Observations in the Northern South China Sea
Authors: Xie L. , Chen L. , Zheng Q. , Wang G. , Yu J. , Xiong X. , Jiang W. , Zhang P. , Zhang Z. 
Published: October 2024

AbstractMooring observations have revealed that the daily reappeared time (DRt) of internal solitary waves (ISWs) in the northern South China Sea (SCS) manifests systematic shifts. This study aims to reveal the dynamic mechanisms behind this phenomenon using the theory of modulation of shear flow to the internal tide wave (IT) propagation. Approximate solutions for the frequency modulation function (FMF) and the amplitude modulation function (AMF) of ITs are derived and validated by the mooring array measurements on the northern SCS continental shelf in 2019 and 2020. Namely, the mechanisms of the ISW reappeared period shift (RPS derived from DRt) and amplitude variation are attributed to the modulation of low‐frequency flow with a period of about 7 days to ITs. The FMF is induced by the vorticity of the low‐frequency flow (FS1) and the Doppler shift (FS2). Thus, the sign of the FMF value may be positive (blue shift) and negative (red shift), depending on the algebraic summation of the two terms. The FS2 derived from mooring observed velocities confirms the modulation effects of mean current on the frequency shift and the amplitude variation of ITs and ISWs.
Age of Stratospheric Air: Progress on Processes, Observations, and Long‐Term Trends
Authors: Garny H. , Ploeger F. , Abalos M. , Bönisch H. , Castillo A. E. , von Clarmann T. , Diallo M. , Engel A. , Laube J. C. , Linz M. , Neu J. L. , Podglajen A. , Ray E. , Rivoire L. , Saunders L. N. , Stiller G. , Voet F. , Wagenhäuser T. , Walker K. A. 
Published: October 2024

AbstractAge of stratospheric air is a well established metric for the stratospheric transport circulation. Rooted in a robust theoretical framework, this approach offers the benefit of being deducible from observations of trace gases. Given potential climate‐induced changes, observational constraints on stratospheric circulation are crucial. In the past two decades, scientific progress has been made in three main areas: (a) Enhanced process understanding and the development of process diagnostics led to better quantification of individual transport processes from observations and to a better understanding of model deficits. (b) The global age of air climatology is now well constrained by observations thanks to improved quality and quantity of data, including global satellite data, and through improved and consistent age calculation methods. (c) It is well established and understood that global models predict a decrease in age, that is, an accelerating stratospheric circulation, in response to forcing by greenhouse gases and ozone depleting substances. Observational records now confirm long‐term forced trends in mean age in the lower stratosphere. However, in the mid‐stratosphere, uncertainties in observational records are too large to confirm or disprove the model predictions. Continuous monitoring of stratospheric trace gases and further improved methods to derive age from those tracers will be crucial to better constrain variability and long‐term trends from observations. Future work on mean age as a metric for stratospheric transport will be important due to its potential to enhance the understanding of stratospheric composition changes, address climate model biases, and assess the impacts of proposed climate geoengineering methods.
Effective Bulk Rheology of a Two‐Phase Subduction Shear Zone: Insights From Micromechanics‐Based Modeling and Implications for Subduction Interface Slow Slip Events
Authors: Lu Lucy Xi , Beall Adam , Fagereng Åke 
Published: October 2024

AbstractSubduction interfaces exhibit various slip styles, including slow slip events (SSEs). We use a micromechanics‐based approach to calculate the effective rheology of a shear zone containing ellipsoidal amphibolite clasts deforming by dislocation creep within an interconnected linear‐viscous phyllosilicate‐dominated matrix. Frictional failure occurs if local stress exceeds Mohr‐Coulomb yield strength. At moderate fluid overpressure, mixed‐frictional‐viscous behavior emerges at 350–560C, consistent with a broad zone of mixed fault slip behavior without requiring extreme fluid overpressures. Increasing stress in this transition zone promotes local frictional failure and raises bulk strain rate. If, however, the bulk strain rate increases by more than one order of magnitude, system‐wide frictional sliding becomes preferable. This strain rate increase is insufficient to explain the slip rates observed in geophysically detectable SSEs. Therefore, viscous matrix flow as modeled here cannot explain SSEs without either invoking dynamic weakening within a frictional‐viscous flow or a mechanism switch to dominantly frictional sliding.
Ionospheric and Thermospheric Effects of Hurricane Grace in 2021 Observed by Satellites
Authors: Gann Ayden L. S. , Yiğit Erdal 
Published: October 2024

AbstractEffects of Hurricane Grace in August 2021 are studied in the thermosphere and ionosphere, using data from the COSMIC‐2, ICON, and GOLD satellites. Significant impacts on electron density, thermospheric winds, and temperature are observed after the onset of the hurricane, compared to the pre‐hurricane phase. Comparison of the observations during the hurricane with the ones during a non‐hurricane year clearly provides further evidence for substantial hurricane‐induced thermospheric and ionospheric changes. We reveal an enhancement in electron density during the hurricane's rapid intensification and pronounced changes in thermospheric winds. Additionally, the low‐latitude thermosphere exhibits considerable warming of up to 70 K around 150 km during this period. These changes highlight the long‐range vertical coupling mechanisms between hurricanes and the upper atmosphere, and provide valuable insights into the profound influence of meteorological events on upper atmospheric dynamics, emphasizing the need for further exploration.
Seasonal Variability in Baffin Bay
Authors: Shan Xuan , Spall Michael A. , Pennelly Clark , Myers Paul G. 
Published: October 2024

AbstractThree dominant characteristics and underlying dynamics of the seasonal cycle in Baffin Bay are discussed. The study is based on a regional, high‐resolution coupled sea ice‐ocean numerical model that complements our understanding drawn from observations. Subject to forcing from the atmosphere, sea ice, Greenland, and other ocean basins, the ocean circulation exhibits complex seasonal variations that influence Arctic freshwater storage and export. The basin‐scale barotropic circulation is generally stronger (weaker) in summer (winter). The interior recirculation (∼2 Sv) is primarily driven by oscillating along‐topography surface stress. The volume transport along the Baffin Island coast is also influenced by Arctic inflows (∼0.6 Sv) via Smith Sound and Lancaster Sound with maximum (minimum) in June‐August (October‐December). In addition to the barotropic variation, the Baffin Island Current also has changing vertical structure with the upper‐ocean baroclinicity weakened in winter‐spring. It is due to a cross‐shelf circulation associated with spatially variable ice‐ocean stresses that flattens isopycnals. Greenland runoff and sea ice processes dominate buoyancy forcing to Baffin Bay. Opposite to the runoff that freshens the west Greenland shelf, stronger salinification by ice formation compared to freshening by ice melt enables a net densification in the interior of Baffin Bay. Net sea ice formation in the past 30 years contributes to ∼25% of sea ice export via Davis Strait. The seasonal variability in baroclinicity and water mass transformation changes in recent decades based on the simulation.
Unraveling Urban NOx Emission Sources in Polluted Arctic Wintertime Using NO2 Nitrogen Isotopes
Authors: Albertin Sarah , Bekki Slimane , Savarino Joël , Brett Natalie , Law Kathy S. , Cesler‐Maloney Meeta , Flynn James H. , Guo Fangzhou , Barret Brice , Caillon Nicolas , D’Anna Barbara , Dieudonné Elsa , Lamothe Alexis , Richard Soline , Temime‐Roussel Brice , Alexander Becky , Arnold Steve R. , Decesari Stefano , Fochesatto Gilberto J. , Mao Jingqiu , Simpson William 
Published: October 2024

AbstractNitrogen (N) isotopic fractionation during nitrogen oxides (NOx) cycling and conversion into atmospheric nitrate alters the original N isotopic composition (δ15N) of NOx emissions. Limited quantification of these isotopic effects in urban settings hampers the δ15N‐based identification and apportionment of NOx sources. δ15N of nitrogen dioxide (NO2) measured during winter in downtown Fairbanks, Alaska, displayed a large temporal variability, from −10.2 to 24.1‰. δ15N(NO2) records are found to be driven by equilibrium isotopic fractionation, at a rate in very close agreement with theoretical predictions. This result confirms that N isotopic partitioning between NO and NO2 can be accurately predicted over a wide range of conditions. This represents an important step for inferring NOx emission sources from isotopic composition measurement of reactive nitrogen species. After correcting our δ15N(NO2) measurements for N fractionation effects, a δ15N‐based source apportionment analysis identifies vehicle and space heating oil emissions as the dominant sources of breathing‐level NOx at this urban site. Despite their large NOx emissions, coal‐fired power plants with elevated chimney stacks (>26 m) appear to make a small contribution to surface NOx levels in downtown Fairbanks (likely less than 18% on average). The combined uncertainties of the δ15N of NOx from heating oil combustion and of the influence of low temperatures on the δ15N of NOx emitted by vehicle exhaust prevent a more detailed partitioning of surface NOx sources in Fairbanks.
Using Geostationary Satellite Observations and Machine Learning Models to Estimate Ecosystem Carbon Uptake and Respiration at Half Hourly Time Steps at Eddy Covariance Sites
Authors: Ranjbar Sadegh , Losos Daniele , Hoffman Sophie , Cuntz Matthias , Stoy Paul C. 
Published: October 2024

AbstractPolar‐orbiting satellites have significantly improved our understanding of the terrestrial carbon cycle, yet they are not designed to observe sub‐daily dynamics that can provide unique insight into carbon cycle processes. Geostationary satellites offer remote sensing capabilities at temporal resolutions of 5‐min, or even less. This study explores the use of geostationary satellite data acquired by the Geostationary Operational Environmental Satellite—R Series (GOES‐R) to estimate terrestrial gross primary productivity (GPP) and ecosystem respiration (RECO) using machine learning. We collected and processed data from 126 AmeriFlux eddy covariance towers in the Contiguous United States synchronized with imagery from the GOES‐R Advanced Baseline Imager (ABI) from 2017 to 2022 to develop ML models and assess their performance. Tree‐based ensemble regressions showed promising performance for predicting GPP (R2 of 0.70 ± 0.11 and RMSE of 4.04 ± 1.65 μmol m−2 s−1) and RECO (R2 of 0.77 ± 0.10 and RMSE of 0.90 ± 0.49 μmol m−2 s−1) on a half‐hourly time step using GOES‐R surface products and top‐of‐atmosphere observations. Our findings align with global efforts to utilize geostationary satellites to improve carbon flux estimation and provide insight into how to estimate terrestrial carbon dioxide fluxes in near‐real time.
Structural Uncertainty in the Sensitivity of Urban Temperatures to Anthropogenic Heat Flux
Authors: Li Dan , Sun Ting , Yang Jiachuan , Zhang Ning , Vahmani Pouya , Jones Andrew 
Published: October 2024

AbstractOne key source of uncertainty for weather and climate models is structural uncertainty arising from the fact that these models must simplify or approximate complex physical, chemical, and biological processes that occur in the real world. However, structural uncertainty is rarely examined in the context of simulated effects of anthropogenic heat flux in cities. Using the Weather Research and Forecasting (WRF) model coupled with a single‐layer urban canopy model, it is found that the sensitivity of urban canopy air temperature to anthropogenic heat flux can differ by an order of magnitude depending on how anthropogenic heat flux is released to the urban environment. Moreover, varying model structures through changing the treatment of roof‐air interaction and the parameterization of convective heat transfer between the canopy air and the atmosphere can affect the sensitivity of urban canopy air temperature by a factor of 4. Urban surface temperature and 2‐m air temperature are less sensitive to the methods of anthropogenic heat flux release and the examined model structural variants than urban canopy air temperature, but their sensitivities to anthropogenic heat flux can still vary by as much as a factor of 4 for surface temperature and 2 for 2‐m air temperature. Our study recommends using temperature sensitivity instead of temperature response to understand how various physical processes (and their representations in numerical models) modulate the simulated effects of anthropogenic heat flux.
Constructing Long‐Term Hydrographs for River Climate‐Resilience: A Novel Approach for Studying Centennial to Millennial River Behavior
Authors: Fathi Mohamed M. , Smith Virginia , Awadallah Ayman G. , Fernandes Anjali M. , Hren Michael T. , Terry Dennis O. 
Published: October 2024

AbstractStudying the centennial or millennial timescale response of large rivers to changing patterns in precipitation, discharge, flood intensity and recurrence, and associated sediment erosion is critical for understanding long‐term fluvial geomorphic adjustment to climate. Long hydrographs, maintaining reliable Flow Duration Curves (FDCs), are a fundamental input for such simulations; however, recorded discharge series rarely span more than a few decades. The absence of robust methodologies for generating representative long‐term hydrographs, especially those incorporating coarse temporal resolution or lacking continuous simulations, is therefore a fundamental challenge for climate resilience. We present a novel approach for constructing multi‐century hydrographs that successfully conserve the statistical, especially frequency analysis, and stochastic characteristics of observed hydrographs. This approach integrates a powerful combination of a weather generator with a fine disaggregation technique and a continuous rainfall‐runoff transformation model. We tested our approach to generate a statistically representative 300‐year hydrograph on the Ninnescah River Basin in Kansas, using a satellite precipitation data set to address the considerable gaps in the available hourly observed data sets. This approach emphasizes the similarities of FDCs between the observed and generated hydrographs, exhibiting a reasonably acceptable range of average absolute deviation between 6% and 18%. We extended this methodology to create projected high‐resolution hydrographs based on a range of climate change scenarios. The projected outcomes present pronounced increases in the FDCs compared to the current condition, especially for more distant futures, which necessitates more efficient adaptation strategies. This approach represents a paradigm shift in long‐term hydrologic modeling.
Upregulation of cholinergic modulators Lypd6 and Lypd6b associated with autism drives anxiety and cognitive decline
Authors: Isaev Aizek B. , Bychkov Maxim L. , Kulbatskii Dmitrii S. , Andreev-Andrievskiy Alexander A. , Mashkin Mikhail A. , Shulepko Mikhail A. , Shlepova Olga V. , Loktyushov Eugene V. , Latanov Alexander V. , Kirpichnikov Mikhail P. , Lyukmanova Ekaterina N. 
Published: October 2024

AbstractIntellectual disability and autistic features are associated with chromosome region 2q23.q23.2 duplication carrying LYPD6 and LYPD6B genes. Here, we analyzed LYPD6 and LYPD6B expression in patients with different neuropsychiatric disorders. Increased LYPD6 and LYPD6B expression was revealed in autism and other disorders. To study possible consequences of Lypd6 and Lypd6b overexpression in the brain, we used a mouse model with intracerebroventricular delivery of recombinant analogs of these proteins. A two-week infusion evoked significant memory impairment and acute stress. Both modulators downregulated hippocampal and amygdala dendritic spine density. No changes in synaptic plasticity were observed. Intracerebroventricular administration by both proteins downregulated hippocampal expression of Lypd6, Lypd6b, and α7 nicotinic acetylcholine receptor (nAChR). Similar to Lypd6, Lypd6b targeted different nAChR subtypes in the brain with preferential inhibition of α7- and α4β2-nAChRs. Thus, increased Lypd6 and Lypd6b level in the brain are linked to cholinergic system depression, neuronal atrophy, memory decline, and anxiety.
Sleep restriction exacerbates cardiac dysfunction in diabetic mice by causing cardiomyocyte death and fibrosis through mitochondrial damage
Authors: Zhang Jingyi , Zhao Xu , Tang Jing , Liu Ce , Zhang Yining , Cai Cheng , Du Qingfeng 
Published: October 2024

AbstractDiabetic cardiomyopathy (DCM) is a cardiovascular complication of diabetes mellitus with a poor prognosis and is the leading cause of death in diabetic patients. Sleep deficiency is not only recognized as an important risk factor for the development of type 2 DM, but is also associated with increased morbidity and mortality of cardiovascular disease. The underlying role and mechanisms of sleep restriction (SR) in DCM are far from clear. The KK/Upj-Ay mouse model of T2 DM was used as a study subject, and the small animal ultrasound imaging system was used to detect the function of the heart; immunopathological staining was used to clarify the histo-structural pathological alterations of the heart; and TUNEL staining, qPCR, transmission electron microscopy (TEM), and ELISA kits were used to detect apoptosis, oxidative stress, inflammation, and mitochondrial damage, and related molecular alterations. SR led to a significant increase in mortality, cardiac hypertrophy, necrosis, glycogen deposition and fibrosis further deteriorated in DM KK mice. SR increased cardiomyocyte death in KK mice through the Bax/Bcl2 pathway. In addition to this, SR not only exacerbated the inflammatory response, but also aggravated mitochondrial damage and promoted oxidative stress in KK mice through the PRDM16-PGC-1α pathway. Overall, SR exacerbates structural alterations and dysfunction through inflammation, oxidative stress, and apoptosis in DM KK mice, increasing the risk of death. Clinicians and diabetic patients are prompted to pay attention to sleep habits to avoid accelerating the transition of DCM to heart failure and inducing death due to poor sleep habits.
Stoichiometric effect on the defect states and optical properties of LiInSe2 single crystals
Authors: Zheng Zhi , Yu Hui , Zhu Menghua , Zhang Zheren , Gao Zhihui , Xu Meng , Zhang Rui , Xu Yadong 
Published: October 2024

AbstractLiInSe2 crystals are promising semiconductor materials for neutron detectors due to the large neutron capture cross-sectional area of the specific isotopes (6Li) and high charge transport properties. However, the optoelectronic performance fails to reach the expected level due to the difficulty of controlling the crystal defects. Herein, we modulate the stoichiometric ratio to control the type of defects in single LiInSe2 crystals grown by the vertical Bridgman method. The UV‒vis–NIR transmission results indicate that the band gap of the yellow colored Li1.01In1Se2 sample is close to ~ 2.83 eV at room temperature, and this value is consistent with the theoretical band gap of LiInSe2 (~ 2.86 eV). Photoluminescence (PL) spectroscopy was used to analyze the defect concentration. The results indicate that the defect types in the yellow Li1.01In1Se2 single crystal are VSe+ and LiIn2−; these result from the introduction of excess Li and the suppression of the adverse defects in InLi2+ and VLi−. These results demonstrate a feasible route for obtaining high-quality yellow 6LiInSe2 crystals and promote the application of 6LiInSe2 neutron detectors.
Capturing fine-scale coral dynamics with a metacommunity modelling framework
Authors: Cresswell Anna K. , Haller-Bull Vanessa , Gonzalez-Rivero Manuel , Gilmour James P. , Bozec Yves-Marie , Barneche Diego R. , Robson Barbara , Anthony Kenneth R. N. , Doropoulos Christopher , Roelfsema Chris , Lyons Mitchell , Mumby Peter J. , Condie Scott , Lago Veronique , Ortiz Juan-Carlos 
Published: October 2024

AbstractNatural systems exhibit high spatial variability across multiple scales. Models that can capture ecosystem dynamics across space and time by explicitly incorporating major biological mechanisms are crucial, both for management and for ecological insight. In the case of coral reef systems, much focus has been on modelling variability between reefs, despite substantial variability also existing within reefs. We developed C~scape, a coral metacommunity modelling framework that integrates the demography of corals with population-level responses to physical and environmental spatial layers, to facilitate spatiotemporal predictions of coral dynamics across reefs at fine (100s of metres to kilometres) scales. We used satellite-derived habitat maps to modulate community growth spatially, as a proxy for the many interacting physical and environmental factors—e.g., depth, light, wave exposure, temperature, and substrate type—that drive within-reef variability in coral demography. With a case study from the Great Barrier Reef, we demonstrate the model’s capability for producing hindcasts of coral cover dynamics and show that overlooking within-reef variability may lead to misleading conclusions about metacommunity dynamics. C~scape provides a valuable framework for exploring a range of management and restoration scenarios at relevant spatial scales.
The emission and physicochemical properties of airborne microplastics and nanoplastics generated during the mechanical recycling of plastic via shredding
Authors: Swinnerton S. , Su J. , Tsai Candace S. J. 
Published: October 2024

AbstractThis study examined the emission and physicochemical properties of microplastics and nanoplastics (MPs/NPs) generated during shredding, which is regularly used in mechanical recycling. Waste and new polyethylene terephthalate, polypropylene, and high-density polyethylene were investigated herein for a total of six categories. The concentration and size distribution of particles were measured using two spectrometer instruments, and morphology and elemental composition of emitted particles were analyzed with microscopy and spectroscopy. This study found that number concentrations in both submicron and micron sizes of respirable particles were 3–2910× higher during periods of shredding than pre-shredding background concentrations. Maximum concentrations of particles within 10–420 nm, across all six categories, ranged from 22,000- to 1,300,000-particles/cm3 during shredding, compared to average background levels of 700 particles/cm3. Maximum concentrations of particles within 0.3 to 10 μm, across all six categories, ranged from 24- to 2000-particles/cm3 during shredding, compared to average background levels of 2 particles/cm3. Waste plastics consistently generated higher emissions than their new counterparts, which is attributed to the labels, adhesives, and increased additives incorporated into the waste plastic. Morphology varied drastically between particles and an elemental composition analysis found that the samples consisted primarily of C and O, representing the polymer material, as well as Na, Mg, Al, Si, Cu, Cl, K, Ca, Ti, Fe, Rb, and Br representing additives, label, and other contaminates. The shredding of plastic has the potential to expose workers to elevated concentrations of airborne MPs/NPs, especially those between 10 and 100 nm.