bluuebunny/crossref_metadata_2025_split huggingface dataset:
Long‐Term Variability in Pliocene North Pacific Ocean Export Production and Its Implications for Ocean Circulation in a Warmer World
Authors: Abell Jordan T. , Winckler Gisela 
Published: August 2023

AbstractUnlike in the high‐latitude North Atlantic, no deep water is formed in the modern subarctic North Pacific. It has previously been suggested that during climate states different from today, this dichotomy did not endure, and the formation of North Pacific Deepwater (NPDW) occurred in the subarctic North Pacific, which supported an active Pacific meridional overturning circulation (PMOC). Here we provide new records of productivity and sedimentary redox conditions from the central subarctic North Pacific spanning the late Miocene to early Pleistocene. These reconstructions indicate greater‐than‐modern and temporally varying North Pacific export production across the interval of ∼2.7–6 Ma. Our time series, combined with previously published data sets and model output for Pliocene North Pacific Ocean dynamics, support the presence of an active PMOC during the Pliocene, and suggest that the characteristics of NPDW formation varied during this warmer interval of Earth's history. This finding of elevated export production at a time of deep water formation presents a conundrum when considering Quaternary North Pacific Ocean dynamics, where subarctic North Pacific productivity declines during intervals when enhanced overturning is posited to occur. We evaluate our data considering the caveats of both (i.e., Pliocene and Quaternary North Pacific circulation) hypotheses, as well as additional mechanisms unrelated to ocean circulation. Because the Pliocene is a possible analogue for near‐future climate, our results and analyses have important ramifications for our understanding of regional and global climate in the coming decades as the planet continues to warm.
A Numerical Study of Dam‐Break Driven Swash and Beach Groundwater Interactions
Authors: Delisle Marie‐Pierre C. , Kim Yeulwoo , Gallien Timu W. 
Published: August 2023

AbstractThe dynamic interaction between swash and beach groundwater is fundamental to understanding wave runup and sediment transport processes. A numerical model that simultaneously resolves free surface and porous media flow for a variably saturated subsurface is presented. The novel numerical model, SedOlaFlow, is developed by merging the existing two‐phase, Eulerian sediment transport model, SedWaveFoam, with the surface wave solver, olaFlow. SedOlaFlow is validated with large wave flume surface and subsurface data for dam‐break driven swash over permeable gravel and sand beaches. Sediment size significantly impacts the swash‐groundwater relationship through infiltration/exfiltration and subsurface processes which modulate runup. Model results demonstrate that vertical infiltration into the upper unsaturated beach leads to a delayed groundwater table response to swash in the sand beach. Pressure fluctuations in the sand beach are not directly indicative of the swash depth or groundwater table and exfiltration may occur even when the swash depth is non‐zero. Groundwater circulation induced by a single swash event is non‐uniform and highly dynamic in the variably saturated vadose zone. Elevated ambient groundwater levels generally increase swash extent and duration. These findings establish the existence of a bi‐directional relationship between swash and groundwater flows and have significant implications on the effects of sea level rise on coastal flooding.
Improving CINRAD Radar QPE Through GPM‐DPR Reflectivity Bias Correction
Authors: Zhu Ziwei , Qi Youcun , Li Donghuan 
Published: August 2023

AbstractReflectivity bias of ground‐based weather radar (GR) is a common error source that can lead to biases in quantitative precipitation estimation (QPE). In this study, the Dual‐frequency Precipitation Radar onboard the Global Precipitation Measurement Mission Core Observatory (GPM‐DPR) is used to correct GR reflectivity bias. The reflectivity bias correction comprehensively considers variations in GR‐DPR reflectivity difference associated with radar frequency difference, data matching approach, precipitation type, GR orographic beam blockage, attenuation, and sample size. The criteria to perform a robust GR‐DPR comparison are presented. Disdrometer validation, based on eight typical rain events from April to August 2019, demonstrates that GPM‐DPR can effectively reduce GR reflectivity bias to ±1 dB. For the period from June to August 2021, the reflectivity correction method is applied to 17 operational GRs. The multiradar QPE shows a significant increase in correlation coefficient (from 0.62 to 0.71), and decreases in relative mean bias (from −0.28 to −0.19) and root mean square error (from 3.96 to 3.54 mm) compared to rain gauges. These results confirm that GPM‐DPR can effectively correct the reflectivity biases of a GR network and improve multiradar QPE accuracy and consistency.
Making a Superbolt: Reconciling Observations of the Optically Brightest Lightning on Earth From Different Satellites
Authors: Peterson Michael 
Published: August 2023

AbstractWe previously documented geographic distributions of the optically brightest lightning on Earth—known as “superbolts”—using two space‐based instruments: the photodiode detector (PDD) on the Fast On‐orbit Recording of Transient Events (FORTE) satellite and the Geostationary Lightning Mapper (GLM) on NOAA's Geostationary Operational Environmental Satellites. In this study, we further examine the superbolts identified by the PDD and GLM to reconcile the differences between their geographic distributions. We find that both the physical extent of the parent flash and the development speed of its leaders are important for making a superbolt. The oceanic PDD superbolts tend to occur early in flashes that rapidly expand laterally into long horizontal “megaflashes.” The top GLM superbolts occur over land at later times in particularly large megaflashes. These land‐based flashes grow more slowly until they extend over multiple hundreds of kilometers. The FORTE PDD missed these delayed superbolts due to limitations in its triggering. Coincident Tropical Rainfall Measuring Mission measurements show that the warm season megaflash superbolts detected by Lightning Imaging Sensor/GLM and wintertime oceanic superbolts observed by the PDD occur in otherwise similar thunderstorm environments. Both are marked by: low storm heights (<10 km), widespread precipitation near the surface, small infrared brightness temperature gradients, and low flash rates. We suggest that the vertically compact, stratiform nature of these clouds provides favorable conditions for superbolt production.
Role of Horizontal Heat Advection in Arctic Surface Warming During Early Spring
Authors: Dai Haijin 
Published: August 2023

AbstractReanalysis data and numerical model are employed to uncover the mechanisms of spring (March–April) Arctic surface warming. Different from other seasons, little additional solar radiation absorption or seasonal heat storage release contributes to Arctic surface warming in spring. Both observation and numerical results suggest that horizontal heat advection dominates Arctic surface air warming. However, horizontal advection originates from lower latitudes instead of local energy redistribution as in other seasons. Furthermore, Arctic warming weakens the meridional potential vorticity gradient, which strengthens the synoptic atmospheric blocking event. As a result, more warm (cold) air is transported to higher (lower) latitudes along the edge of high pressure, which is an accumulation of atmospheric blocking events. The results suggest that anomalous meridional heat transport plays more important roles in Arctic surface warming when the anomalous radiative forcing is weak. Without being absorbed by the ocean, additional available energy induces strong Arctic springtime surface warming.
Cold Springs Over Mid‐Latitude North America Induced by Tropical Atlantic Warming
Authors: Hou Yurong , Johnson Nathaniel C. , Chang Chueh‐Hsin , Sun Weijun , Man Kai , Miao Yujie , Li Xichen 
Published: August 2023

AbstractIn recent decades, severe cold winters and springs have frequently occurred over mid‐latitude North America, despite the anthropogenic global warming trend. In this study, we reveal a possible mechanism by investigating the teleconnection between tropical oceans and North America. Through observational analysis and numerical experiments, we reveal that an anomalous tropical Atlantic warming can trigger a cold spring over central‐western mid‐latitude North America. The tropical Atlantic warming intensifies regional deep atmospheric convection and generates a stationary Rossby wave train propagating poleward, forming an anomalous low pressure center over the mid‐latitude North Atlantic. This low‐level circulation adjustment further intensifies the cold advection and increases the cloud cover over central‐western North America, cooling the surface through cloud radiative feedback. The mechanisms revealed in this study may contribute to the improvement of predictability of cold springs over North America, and have broad implications for agriculture production, power supply, and public health.
Sensitivity of Pyrocumulus Convection to Tree Mortality During the 2020 Creek Fire in California
Authors: Lee Jungmin M. , Mirocha Jeffrey D. , Lareau Neil P. , Whitney Taylor , To Wing , Kochanski Adam , Lassman William 
Published: August 2023

AbstractThis study investigated the sensitivity of pyrocumulonimbus (PyroCb) induced by the California Creek fire of 2020 to the amount and type of surface fuels, within the WRF‐SFIRE modeling system. Satellite data were used to derive fire arrival times to constrain fire progression, and to augment the fuel characterization with better estimates of combustible vegetation accounting for tree mortality. Machine learning was employed to classify standing dead vegetation from aerial imagery, which was then added as a custom fuel class along with the standard Anderson fuel categories. Simulations using this new fuel class produced a larger and more vigorous PyroCb than the control run, however, still under‐predicted the cloud top. Additional augmentation of fuel mass to represent the accumulation of dead vegetation on the forest floor further improved the simulations, demonstrating the efficacy of representing both dead standing and fallen vegetation to produce more realistic PyroCb and smoke simulations.
Energy Transfer Between Mesoscale Eddies and Near‐Inertial Waves From Surface Drifter Observations
Authors: Liu Gengbin , Chen Zhiwu , Lu Huaihao , Liu Zhiyu , Zhang Qian , He Qingyou , He Yinghui , Xu Jiexin , Gong Yankun , Cai Shuqun 
Published: August 2023

AbstractHourly satellite‐tracked surface drifter data are utilized to study energy transfer from eddies to Near‐Inertial Waves (NIWs). Spatial velocity gradients are computed from two consecutive velocity estimates derived from the same drifter, providing variable spatial resolutions of O(1 km). The eddy‐to‐NIW energy transfer can be positive or negative, with the positive transfer (forward energy cascade) dominant. The global integrated energy transfer rate (ε) is 0.025 TW, with the anticyclonic eddy contribution dominant over the cyclonic eddy contribution. Given that the global near‐inertial wind work (W) is 0.2 TW, the eddy‐to‐NIW energy transfer efficiency (ε/W) is about 13%, which is one order of magnitude larger than that in low resolution simulations. This result may still underestimate the Eulerian energy transfer by a factor of 2. To our knowledge, this is the first time that this energy transfer is calculated from global drifter observations, providing a baseline for comparison in future studies.
Nutritional Status Regulates Bacteria‐Virus Interactions in the Northern South China Sea
Authors: Li Xiangfu , He Maoqiu , Shi Zhen , Xu Jie 
Published: August 2023

AbstractHeterotrophic bacteria play a vital role in the marine carbon cycle and viruses are an important regulator of bacterial metabolism and community composition. It remains unclear about how bacteria‐virus interactions vary with environmental conditions in oceans. In this study, bacterial metabolic activity and community composition were examined in three treatments with different viral pressure (control, virus‐rich and virus‐reduced) through bioassay experiments at three stations with different environmental conditions in the shelf of the northern South China Sea. Our results showed that bacteria‐virus interactions varied with environmental conditions. Viral lysis mediated bacterial growth rate (BGR) and production by shaping bacterial community composition. Furthermore, the effect of viral lysis on bacterial growth rate and production was reduced in substrate‐rich waters compared to substrate‐low waters. However, the opposite pattern occurred for viral regulation on bacterial respiration and carbon demand, likely since viral lysis dramatically mitigated the maintenance respiration of bacteria. Consequently, viral lysis to greater extent mitigated bacterial carbon processing in substrate‐rich environments than in substrate‐low environments. Our findings provided new insights into bacteria‐virus interactions, and improved our understanding of the role microbial processes in carbon cycling in oceans.
Simulating Sea‐Ice Deformation in Viscous‐Plastic Sea‐Ice Models With CD‐Grids
Authors: Mehlmann C. , Capodaglio G. , Danilov S. 
Published: August 2023

AbstractLinear kinematic features (LKFs) are found everywhere in the Arctic sea‐ice cover. They are strongly localized deformations often associated with the formation of leads and pressure ridges. In viscous‐plastic (VP) sea‐ice models, the simulation of LKFs depends on several factors such as the grid resolution, the numerical solver convergence, and the placement of the variables on the mesh. In this study, we compare two recently proposed discretization with a CD‐grid placement with respect to their ability to reproduce LKFs. The first (CD1) is based on a nonconforming finite element discretization, whereas the second (CD2) uses a conforming subgrid discretization. To analyze their resolution properties, we evaluate runs from different models (e.g., FESOM, MPAS) on a benchmark problem using quadrilateral, hexagonal and triangular meshes. Our findings show that the CD1 setup simulates more deformation structure than the CD2 setup. This highlights the importance of the type of spatial discretization for the simulation of LKFs. Due to the higher number of degrees of freedom, both CD‐grids resolve more LKFs than traditional A, B, and C‐grids at fixed mesh level. This is an advantage of the CD‐grid approach, as high spatial mesh resolution is needed in VP sea‐ice models to simulate LKFs.
A microfluidic biosensor for the diagnosis of chronic wasting disease
Authors: Muhsin Sura A. , Abdullah Amjed , kobashigawa Estela , Al-Amidie Muthana , Russell Sherri , Zhang Michael Z. , Zhang Shuping , Almasri Mahmoud 
Published: August 2023

AbstractCervids are affected by a neurologic disease that is always fatal to individuals and has population effects. This disease is called chronic wasting disease (CWD) and is caused by a misfolded prion protein. The disease is transmitted via contact with contaminated body fluids and tissue or exposure to the environment, such as drinking water or food. Current CWD diagnosis depends on ELISA screening of cervid lymph nodes and subsequent immunohistochemistry (IHC) confirmation of ELISA-positive results. The disease has proven to be difficult to control in part because of sensitivity and specificity issues with the current test regimen. We have investigated an accurate, rapid, and low-cost microfluidic microelectromechanical system (MEMS) biosensing device for the detection of CWD pathologic prions in retropharyngeal lymph nodes (RLNs), which is the current standard type of CWD diagnostic sample. The device consists of three novel regions for concentrating, trapping, and detecting the prion. The detection region includes an array of electrodes coated with a monoclonal antibody against pathologic prions. The experimental conditions were optimized using an engineered prion control antigen. Testing could be completed in less than 1 hour with high sensitivity and selectivity. The biosensor detected the engineered prion antigen at a 1:24 dilution, while ELISA detected the same antigen at a 1:8 dilution. The relative limit of detection (rLOD) of the biosensor was a 1:1000 dilution of a known strong positive RLN sample, whereas ELISA showed a rLOD of 1:100 dilution. Thus, the biosensor was 10 times more sensitive than ELISA, which is the currently approved CWD diagnostic test. The biosensor’s specificity and selectivity were confirmed using known negative RPLN samples, a negative control antibody (monoclonal antibody against bovine coronavirus BCV), and two negative control antigens (bluetongue virus and Epizootic hemorrhagic disease virus). The biosensor’s ability to detect pathogenic prions was verified by testing proteinase-digested positive RLN samples.
Journey towards a dental career: the career decision-making journey and perceived obstacles to studying dentistry identified by London's secondary school pupils and teachers
Authors: Niven Victoria , Scambler Sasha , Cabot Lyndon B. , Gallagher Jennifer E. 
Published: August 2023

AbstractObjectiveTo explore the career decision-making journey towards dentistry and identify possible challenges and supports in this process as perceived by academically able, science-minded, London school pupils and their careers teachers.MethodsA mixed-methods study was conducted using a purposive sample of London schools. Focus groups (n = 13) with 91 pupils aged 14-18 years and a survey of career teachers (n = 12) were conducted at a range of school-types. A topic guide, informed by the literature and previous research, guided discussions. Ethical approval was obtained from King's College London Research Ethics Committee (BDM/10/11-17 and 14/15-40). School, teacher, parental and pupil written informed consent were obtained. Data were transcribed and analysed thematically using framework methodology.ResultsFour distinct phases of the career decision-making journey were identified: 1) initiation of aspiration, with wider influences promoting medicine as a primary aspirational career option; 2) exposure to dentistry as a career, leading to recognition of dentistry as an alternative; 3) exploration of the career; and 4) the application process. Dentistry received little early consideration in this process. Greater representation of dental professionals within the school, access to work experience, and support in the student application process were identified as possible supports.ConclusionsThe findings suggest a four-phase journey towards a dental career, which may be enhanced by engagement of dental professionals at each stage. This may be particularly helpful in widening participation from under-represented groups.
Lysine methylation of PPP1CA by the methyltransferase SUV39H2 disrupts TFEB-dependent autophagy and promotes intervertebral disc degeneration
Authors: Liang Huaizhen , Luo Rongjin , Li Gaocai , Zhang Weifeng , Zhu Dingchao , Wu Di , Zhou Xingyu , Tong Bide , Wang Bingjin , Feng Xiaobo , Wang Kun , Song Yu , Yang Cao 
Published: August 2023

AbstractImpaired transcription factor EB (TFEB) function and deficient autophagy activity have been shown to aggravate intervertebral disc (IVD) degeneration (IDD), yet the underlying mechanisms remain less clear. Protein posttranslational modifications (PTMs) are critical for determining TFEB trafficking and transcriptional activity. Here, we demonstrate that TFEB activity is controlled by protein methylation in degenerated nucleus pulposus cells (NPCs), even though TFEB itself is incapable of undergoing methylation. Specifically, protein phosphatase 1 catalytic subunit alpha (PPP1CA), newly identified to dephosphorylate TFEB, contains a K141 mono-methylated site. In degenerated NPCs, increased K141-methylation of PPP1CA disrupts its interaction with TEFB and subsequently blocks TEFB dephosphorylation and nuclear translocation, which eventually leads to autophagy deficiency and NPC senescence. In addition, we found that the PPP1CA-mediated targeting of TFEB is facilitated by the protein phosphatase 1 regulatory subunit 9B (PPP1R9B), which binds with PPP1CA and is also manipulated by K141 methylation. Further proteomic analysis revealed that the protein lysine methyltransferase suppressor of variegation 3–9 homologue 2 (SUV39H2) is responsible for the K141 mono-methylation of PPP1CA. Targeting SUV39H2 effectively mitigates NPC senescence and IDD progression, providing a potential therapeutic strategy for IDD intervention.
A mechanistic reinterpretation of fast inactivation in voltage-gated Na+ channels
Authors: Liu Yichen , Bassetto Carlos A. Z. , Pinto Bernardo I. , Bezanilla Francisco 
Published: August 2023

AbstractThe hinged-lid model was long accepted as the canonical model for fast inactivation in Nav channels. It predicts that the hydrophobic IFM motif acts intracellularly as the gating particle that binds and occludes the pore during fast inactivation. However, the observation in recent high-resolution structures that the bound IFM motif is located far from the pore, contradicts this preconception. Here, we provide a mechanistic reinterpretation of fast inactivation based on structural analysis and ionic/gating current measurements. We demonstrate that in Nav1.4 the final inactivation gate is comprised of two hydrophobic rings at the bottom of S6 helices. These rings function in series and close downstream of IFM binding. Reducing the volume of the sidechain in both rings leads to a partially conductive, leaky inactivated state and decreases the selectivity for Na+ ion. Altogether, we present an alternative molecular framework to describe fast inactivation.
Sequence anticipation and spike-timing-dependent plasticity emerge from a predictive learning rule
Authors: Saponati Matteo , Vinck Martin 
Published: August 2023

AbstractIntelligent behavior depends on the brain’s ability to anticipate future events. However, the learning rules that enable neurons to predict and fire ahead of sensory inputs remain largely unknown. We propose a plasticity rule based on predictive processing, where the neuron learns a low-rank model of the synaptic input dynamics in its membrane potential. Neurons thereby amplify those synapses that maximally predict other synaptic inputs based on their temporal relations, which provide a solution to an optimization problem that can be implemented at the single-neuron level using only local information. Consequently, neurons learn sequences over long timescales and shift their spikes towards the first inputs in a sequence. We show that this mechanism can explain the development of anticipatory signalling and recall in a recurrent network. Furthermore, we demonstrate that the learning rule gives rise to several experimentally observed STDP (spike-timing-dependent plasticity) mechanisms. These findings suggest prediction as a guiding principle to orchestrate learning and synaptic plasticity in single neurons.