bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Algorithm for Thermodynamic Parameter Optimization: Application to the Martian Mantle
Authors: Khan D. , Liebske C. , Connolly J. A. D. 
Published: April 2021

AbstractThe compilation of thermodynamic models for geophysical applications is such a tedious and complex process that it is generally impractical for researchers to refit parameters in existing models in light of new constraints. To mitigate this difficulty, we develop a Bayesian algorithm that permits the modification of a thermodynamic model to account for additional observational constraints. This algorithm can be applied to any thermodynamic dataset and can utilize a wide variety of experimental constraints. To demonstrate the applicability of the algorithm it is used to revise the Stixrude and Lithgow‐Bertelloni (2011, https://doi.org/10.1111/j.1365‐246x.2010.04890.x), whole‐mantle terrestrial thermodynamic model, using phase equilibrium constraints provided by Bertka and Fei (1997, https://doi.org/10.1029/96jb03270), for the more iron‐rich compositions that are thought to be relevant to the Martian mantle. The revised thermodynamic model provides a more reliable prediction of phase equilibria in the Martian mantle. Seismic properties are calculated in an internally self‐consistent manner along hot and cold areotherms to constrain the upper and lower bounds of these properties for different bulk silicate Mars compositional models.
Reducing Surface Wetness Leads to Tropical Hydrological Cycle Regime Transition
Authors: Fan Bowen , Tan Zhihong , Shaw Tiffany A. , Kite Edwin S. 
Published: April 2021

AbstractEarth’s modern climate is characterized by wet, rainy deep tropics, however, paleoclimate and planetary science have revealed a wide range of hydrological cycle regimes connected to different external parameters. Here we investigate how surface wetness affects the tropical hydrological cycle. When surface wetness is decreased in an Earth‐like general circulation model, the tropics remain wet but the transition from a rainy to a rain‐free regime. The rain‐free regime occurs when surface precipitation is suppressed as negative evaporation (surface condensation) balances moisture flux convergence. The regime transition is dominated by near‐surface relative humidity changes in contrast to the hypothesis that relative humidity changes are small. We show near‐surface relative humidity changes responsible for the regime transition are controlled by re‐evaporation of stratiform precipitation near the lifting condensation level. Re‐evaporation impacts the near‐surface through vertical mixing. Our results reveal a new rain‐free tropical hydrological cycle regime that goes beyond the wet/dry paradigm.
Sea Surface Temperatures in the Indian Sub‐Antarctic Southern Ocean for the Last Four Interglacial Periods
Authors: Shukla Sunil Kumar , Crosta Xavier , Ikehara Minoru 
Published: April 2021

AbstractInterglacial periods (IG) offer an opportunity to understand natural climate variability and its drivers under potential warmer‐than‐present conditions. However, sea‐surface temperature (SST) records from the Southern Ocean (SO) are limited. The first SST record from the Sub‐Antarctic western Indian SO covering the last four IGs suggest warmer conditions during Marine Isotope Stage 5e than 9e, 7e, and Holocene. Each IG presents two (early and late) warm phases interrupted by a cooling, except Holocene that experienced a continuous warming. The early warm phase might be attributable to changes in northern summer insolation with feedbacks from Northern and Southern Hemisphere ice‐sheets, global oceanic circulation, and the carbon cycle. Conversely, the late warm phase might be due to changes in Southern Hemisphere summer insolation. Larger millennial‐scale SST variability for IGs older than Holocene could be attributed to a less stable thermohaline circulation, which resulted in more variable heat redistribution between the two hemispheres.
Buoyancy‐Driven Flexure at the Front of Ross Ice Shelf, Antarctica, Observed With ICESat‐2 Laser Altimetry
Authors: Becker Maya K. , Howard Susan L. , Fricker Helen A. , Padman Laurie , Mosbeux Cyrille , Siegfried Matthew R. 
Published: April 2021

AbstractMass loss from Antarctica’s three largest ice shelves is dominated by calving, primarily of large tabular icebergs every few decades. Smaller, more frequent calving events also occur, but it is more difficult to detect them and quantify their contribution to total ice‐shelf mass loss. We used surface elevation data from NASA’s ICESat‐2 laser altimeter to examine the structure of the Ross Ice Shelf front between October 2018 and July 2020. Profiles frequently show a depression a few meters deep about 200–800 m upstream of the front, with higher values on the eastern portion of the ice shelf. This structure results from bending due to buoyancy of a submerged ice bench generated by ice‐front melting near the waterline when warm water is present in summer. These bending stresses may cause small‐scale calving events whose frequency would change as summer sea ice and atmosphere–ocean heat exchanges vary over time.
Possible Links Between Methane Seepages and Glacial‐Interglacial Transitions in the South China Sea
Authors: Deng Yinan , Chen Fang , Guo Qingjun , Hu Yu , Chen Daohua , Yang Shengxiong , Cao Jun , Chen Hong , Wei Rongfei , Cheng Sihai , Zhou Jianhou , Liu Chenhui , Jiang Xuexiao , Zhu Jiang 
Published: April 2021

AbstractMethane seeps are widespread at continental margins, and may exert an influence on climate change. However, many details concerning the relationship between methane seepage and climate change in the geological history remain unclear. Geological records of cold seeps at glacial‐interglacial transitions remain scarce due to the lack of relatively complete records. Here we present geochemical data of seep carbonates from a drill core from the South China Sea, which reveals three stages of methane seepage linked to the dissociation of biogenic methane hydrate: ∼130.3 ka BP before, MIS 5 (∼130.3 to 111.4 ka BP) and MIS 1 (∼11.1 to 10.0 ka BP). Our results evidence that methane seepage was induced by warm seawater and subsequently hydrostatic pressure drop during deglaciations. We suspect this process to occur in other world regions and infer that methane seepage might occur more widespread at glacial‐interglacial transitions, which in turn might have accelerated global warming.
Increasing Influence of Indian Ocean Dipole on Precipitation Over Central Equatorial Africa
Authors: Jiang Yan , Zhou Liming , Roundy Paul E. , Hua Wenjian , Raghavendra Ajay 
Published: April 2021

AbstractUsing observational rainfall datasets, we identify a positive correlation between precipitation over Central Equatorial Africa (CEA) and the Indian Ocean Dipole (IOD) during September‐December (SOND) for the period 1981–2019. Rainfall amount significantly increases during positive IOD events. The enhancement in precipitation is primarily attributed to increased rainfall frequency and reaches the maximum in October. IOD impacts rainfall via modifying the Walker circulation over the tropical Indian Ocean and moisture in the middle troposphere over CEA. The Madden‐Julian Oscillation (MJO) activity covaries with IOD to modulate the African Easterly Jet, which is critical to convection development over CEA. SOND rainfall has increased for the last two decades, which is concurrent with increases in both the IOD index and the correlation between IOD and rainfall. The IOD‐congruent rainfall changes potentially account for much of rainfall trends in southern and eastern CEA.
Lithospheric Control of Melt Generation Beneath the Rungwe Volcanic Province, East Africa: Implications for a Plume Source
Authors: Njinju Emmanuel A. , Stamps D. Sarah , Neumiller Kodi , Gallager James 
Published: April 2021

AbstractThe Rungwe Volcanic Province (RVP) is a volcanic center in an anomalous region of magma‐assisted rifting positioned within the magma‐poor Western Branch of the East African Rift (EAR). The source of sublithospheric melt for the RVP is enigmatic, particularly since the volcanism is highly localized, unlike the Eastern Branch of the EAR. Some studies suggest the source of sublithospheric melt beneath the RVP arises from thermal perturbations in the upper mantle associated with an offshoot of the African superplume flowing from the SW, while others propose a similar mechanism, but from the Kenyan plume diverted around the Tanzania Craton from the NE. Another possibility is decompression melting from upwelling sublithospheric mantle due to lithospheric modulated convection (LMC) where the lithosphere is thin. The authors test the hypothesis that sublithospheric melt feeding the RVP can be generated from LMC. We develop a 3D thermomechanical model of LMC beneath the RVP and the Malawi Rift and constrain parameters for sublithospheric melt generation due to LMC. We assume a rigid lithosphere and use non‐Newtonian, temperature‐, pressure‐, and porosity‐dependent creep laws of anhydrous peridotite for the sublithospheric mantle. We find a pattern of upwelling from LMC beneath the RVP. The upwelling generates melt only for elevated mantle potential temperatures (Tp), which suggests a heat source possibly from plume material. At elevated Tp, LMC associated decompression melts occurs at a maximum depth of ∼150 km beneath the RVP. We suggest upwelling due to LMC entrains plume materials resulting in melt generation beneath the RVP.
Stalling and Dissipation of a Near‐Inertial Wave (NIW) in an Anticyclonic Ocean Eddy: Direct Determination of Group Velocity and Comparison With Theory
Authors: Sanford Thomas B. , Ma Barry B. , Alford Matthew H. 
Published: April 2021

AbstractA near‐inertial wave stalling and breaking in a critical layer was observed for a week by a pair of autonomous velocity and density profilers on concentric paths in an ocean mesoscale eddy. Profiler observations provide estimates of the eddy's vertical vorticity and shear, quantities needed to test theories of downward near‐inertial wave (NIW) energy flux and loss from inertial wave–eddy interactions. The unique observations of the wave's intrinsic frequency and vertical wavenumber m provide a novel estimate of the vertical group velocity Cgz from changes in with respect to m. Shear, strain, energy flux convergence, and parameterized turbulence are all elevated near 140 m depth, near the bottom of the strongest eddy velocities. Our observations are consistent with a downgoing NIW's group velocity decreasing owing to wave–eddy interactions, providing important clues on global energetics of NIW mixing.
A Rainfall‐Based, Sequential Depression‐Filling Algorithm and Assessments on a Watershed in Northeastern Indiana, USA
Authors: Noel S. A. , Ault A. C. , Buckmaster D. R. , Krogmeier J. V. 
Published: April 2021

AbstractThe landscapes across much of the Midwestern United States are characterized by glacial activity that left water‐holding kettles, depressions, and potholes. Until recently, traditional watershed algorithms assumed these depressions to be errors in the elevation data and filled them as a means of correction, when many of these features may rarely fill and have the potential to dramatically affect surface flow patterns. These depressions play an important role in hydrology, water management, site planning, and agronomy. An optimized sequential depression‐filling algorithm (SDFA) was developed which fills these water‐holding features sequentially based on their respective retention capacity and contributing area. Outputs reflect the state of connectivity following the application of a user‐specified amount of rainfall excess (i.e., in excess of infiltration); depressions that have not been filled will remain as their own hydrologically common subcatchments. A performant algorithm is integral to future delivery and utilization by practitioners both in the office and in the field. The optimal set of subroutines were able to fill all of the depressions in a 239 km2watershed in northeastern Indiana in 42 s and 1.5 h on a consumer desktop computer for digital elevation models (DEMs) at 30 m and 3 m resolutions, respectively (O(n2) overall performance).
Multiple Phase Screen Modeling of HF Wave Field Scintillations Caused by the Irregularities in Inhomogeneous Media
Authors: Ding Mingkai , Tong Peng , Wei Yinsheng , Yu Lei 
Published: April 2021

AbstractHigh frequency (HF) radio waves propagating through regions of ionospheric plasma irregularities exhibit random fluctuations in both amplitude and phase referred to as scintillations, which heavily influences the detection performance of HF sky‐wave radar and hybrid sky‐surface wave radar systems. In this paper, a numerical multiple phase screen model for HF sky‐wave propagation is developed, which can simulate the HF wave field scintillations caused by the irregularities in inhomogeneous media. In this model, the random phase changes due to irregularities and the diffraction effect due to phase mixing are considered separately and computed sequentially, where the phase change is numerically calculated using a geometric optical phase delay to allow for the consideration of horizontal electron density gradients. Utilizing the proposed model, we first simulate the observations of scintillation from the direct wave of the HF hybrid sky‐surface wave radar. The statistics of simulation and measured data, including power spectrum and scintillation indices on amplitude and phase, are considered to verify the effectiveness of the proposed model. Then, we analyze the effects of traveling ionospheric disturbances (TIDs) on the intensity of scintillation. The simulation indicates that the horizontal electron density gradients due to TIDs cause the fluctuation of the amplitude scintillation index .
A Strong Sub‐Thermocline Intrusion of the North Equatorial Subsurface Current Into the Makassar Strait in 2016–2017
Authors: Li Mingting , Yuan Dongliang , Gordon Arnold L. , Gruenburg Laura K. , Li Xiang , Li Rui , Yin Xueli , Yang Ya , Corvianatie Corry , Wei Jun , Yang Song 
Published: April 2021

AbstractThe poorly resolved pathway of the sub‐thermocline waters (>300 m) within the Makassar Strait, the primary inflow path of the Indonesian Throughflow, is investigated using in situ mooring measurements and Argo profiles at the entrance to the Indonesian Seas. We focus on the strong sub‐thermocline intrusion in the summer of 2016, when significant changes of sub‐thermocline transport thrice as large as the interannual standard deviation occurred. Analysis suggests that the intrusion was drawn from the North Equatorial Subsurface Current (NESC) flowing westward below the North Equatorial Countercurrent, which was composed of a mixture of intermediate‐depth waters from both the North and South Pacific. The anomalously strong NESC to the Makassar sub‐thermocline in the summer 2016 is suggested to be in response to the 2015/2016 extreme El Niño event, forced by the trade wind anomalies over the western‐central Pacific Ocean through westward and downward propagating baroclinic Rossby waves.
Warming and Freshening of the Pacific Inflow to the Arctic From 1990‐2019 Implying Dramatic Shoaling in Pacific Winter Water Ventilation of the Arctic Water Column
Authors: A. Woodgate Rebecca , Peralta‐Ferriz Cecilia 
Published: April 2021

AbstractThe Pacific inflow to the Arctic traditionally brings heat in summer, melting sea ice; dense waters in winter, refreshing the Arctic’s cold halocline; and nutrients year‐round, supporting Arctic ecosystems. Bering Strait moorings from 1990 to 2019 find increasing (0.010 ± 0.006 Sv/yr) northward flow, reducing Chukchi residence times by ∼1.5 months over this period (record maximum/minimum ∼7.5 and ∼4.5 months). Annual mean temperatures warm significantly (0.05 ± 0.02°C/yr), with faster change (∼0.1°C/yr) in warming (June/July) and cooling (October/November) months, which are now 2°C to 4°C above climatology. Warm (≥0°C) water duration increased from 5.5 months (the 1990s) to over 7 months (2017), mostly due to earlier warming (1.3 ± 0.7 days/yr). Dramatic winter‐only (January–March) freshening (0.03 psu/yr) makes winter waters fresher than summer waters. The resultant winter density change, too large to be compensated by Chukchi sea‐ice processes, shoals the Pacific Winter Water (PWW) equilibrium depth in the Arctic from 100–150 to 50–100 m, implying PWW no longer ventilates the Arctic’s cold halocline at 33.1 psu.
Observations of Ubiquitous Nighttime Temperature Inversions in Mars' Tropics After Large‐Scale Dust Storms
Authors: Steele L. J. , Kleinböhl A. , Kass D. M. 
Published: April 2021

AbstractWe report the ubiquitous occurrence of nighttime temperature inversions in the tropical Martian atmosphere during the dusty season, as observed by the Mars Climate Sounder. The inversions occur after large‐scale regional dust storms, with their strengths largely correlated to the strengths of the dust storms. Inversions strengthen between 2 and 4 a.m., with the bases of the inversions getting cooler, and the tops of the inversions getting warmer. The inversions are strongest and most frequent around Tharsis and Terra Sabaea, but are also observed over the flat plains early in the dust storm decay period. These inversions likely result from the effects of both a strengthened migrating diurnal tide (due to the increased dustiness of the atmosphere), along with nonmigrating tides forced by zonal variations in aerosol abundance and topography. These results highlight an important interplay between the dust distribution, water ice clouds and thermal tides.
Soil Moisture Active Passive Improves Global Soil Moisture Simulation in a Land Surface Scheme and Reveals Strong Irrigation Signals Over Farmlands
Authors: He Liming , Chen Jing M. , Mostovoy Georgy , Gonsamo Alemu 
Published: April 2021

AbstractThe successful Soil Moisture Active Passive (SMAP) mission provides operational soil moisture products of high quality; yet its impacts on global carbon and water cycle estimation are yet to be further investigated. Here we assimilated the SMAP enhanced Level‐2 soil moisture product at 9 km resolution into a land surface scheme in order to study the soil moisture control on the functioning of terrestrial ecosystems. We found that SMAP significantly improves soil moisture simulations, especially in the spring. Extensive wetting signals were revealed over croplands in arid and semi‐arid regions and could not be explained using reanalysis meteorological data, indicating an additional water input, for example, irrigation. Stronger impacts on gross primary production and evapotranspiration simulations are found in wetting adjustments than in drying adjustments after data assimilation. This study suggests that the performance of the land surface scheme benefits greatly from assimilating the SMAP soil moisture product.
A Global Assessment of Coastal Marine Heatwaves and Their Relation With Coastal Urban Thermal Changes
Authors: Hu Leiqiu 
Published: April 2021

AbstractOcean temperature significantly influences global and regional weather and climate. Coastal marine heatwaves (MHWs) do not only profoundly impact marine ecosystems but can influence the climate of coastal regions. This study provides the first observational assessment of global coastal MHWs changes, showing a latitudinal‐dependent pattern with considerably strengthened severity of MHWs in the past four decades. Coastal MHWs have been found closely linked to remarkable changes in coastal urban thermal environments, showing consistent trends of increase in air temperature and moisture, and mostly reduced wind speed among 38 major coastal cities. These effects collectively exacerbate the thermal discomfort during the warm season. The findings demonstrate the strong coupling of coastal oceans and lands under the influence of global warming and regional interactions of ocean, land, and the atmosphere, and contribute to a global initial understanding of the characteristics and co‐variation of thermal extremes over the coastal regions.
Neurocognitive disorders in the elderly: altered functional resting-state hyperconnectivities in postoperative delirium patients
Authors: Winterer Jeanne M. , Ofosu Kwaku , Borchers Friedrich , Hadzidiakos Daniel , Lammers-Lietz Florian , Spies Claudia , Winterer Georg , Zacharias Norman 
Published: April 2021

AbstractPostoperative delirium (POD) represents a confusional state during days/weeks after surgery and is particularly frequent in elderly patients. Hardly any fMRI studies were conducted to understand the underlying pathophysiology of POD patients. This prospective observational cohort study aims to examine changes of specific resting-state functional connectivity networks across different time points (pre- and 3–5 months postoperatively) in delirious patients compared to no-POD patients. Two-hundred eighty-three elderly surgical patients underwent preoperative resting-state fMRI (46 POD). One-hundred seventy-eight patients completed postoperative scans (19 POD). For functional connectivity analyses, three functional connectivity networks with seeds located in the orbitofrontal cortex (OFC), nucleus accumbens (NAcc), and hippocampus were investigated. The relationship of POD and connectivity changes between both time points (course connectivity) were examined (ANOVA). Preoperatively, delirious patients displayed hyperconnectivities across the examined functional connectivity networks. In POD patients, connectivities within NAcc and OFC networks demonstrated a decrease in course connectivity [max. F = 9.03, p = 0.003; F = 4.47, p = 0.036, resp.]. The preoperative hyperconnectivity in the three networks in the patients at risk for developing POD could possibly indicate existing compensation mechanisms for subtle brain dysfunction. The observed pathophysiology of network function in POD patients at least partially involves dopaminergic pathways.
USP24 promotes drug resistance during cancer therapy
Authors: Wang Shao-An , Young Ming-Jer , Wang Yi-Chang , Chen Shu-Hui , Liu Chia-Yu , Lo Yao-An , Jen Hung-Hsiang , Hsu Kai-Cheng , Hung Jan-Jong 
Published: April 2021

AbstractDrug resistance has remained an important issue in the treatment and prevention of various diseases, including cancer. Herein, we found that USP24 not only repressed DNA-damage repair (DDR) activity by decreasing Rad51 expression to cause the tumor genomic instability and cancer stemness, but also increased the levels of the ATP-binding cassette (ABC) transporters P-gp, ABCG2, and ezrin to enhance the pumping out of Taxol from cancer cells, thus resulted in drug resistance during cancer therapy. A novel USP24 inhibitor, NCI677397, was screened for specific inhibiting the catalytic activity of USP24. This inhibitor was identified to suppress drug resistance via decreasing genomic instability, cancer stemness, and the pumping out of drugs from cancer cells. Understanding the role and molecular mechanisms of USP24 in drug resistance will be beneficial for the future development of a novel USP24 inhibitor. Our studies provide a new insight of USP24 inhibitor for clinically implication of blocking drug resistance during chemotherapy.