bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assimilation of IASI Ozone‐Sensitive Channels in Preparation for an Enhanced Coupling Between Numerical Weather Prediction and Chemistry Transport Models
Authors: Coopmann O. , Guidard V. , Fourrié N. , Plu M. 
Published: October 2018

AbstractIn this study, IASI ozone‐sensitive channels have been assimilated in 1D‐Var data assimilation combined with realistic ozone background coming from a MOCAGE (Modèle de Chimie Atmosphérique à Grande Echelle) Chemistry Transport Model (CTM) as a first stage of coupling between Numerical Weather Prediction (NWP) and MOCAGE CTM at Météo‐France for global model ARPEGE (Action de Recherche Petite Echelle Grande Echelle). To evaluate the impact of ozone‐sensitive channels on analyses, databases of 161 temperatures, humidity, and ozone radiosondes across the globe during a 1‐year period have been considered. Ozone forecast from MOCAGE CTM was evaluated with radiosondes and used as input for the Radiative Transfer Model (RTM) RTTOV. Statistics of IASI observations minus simulations show that the use of ozone from MOCAGE CTM allows to better simulate IASI ozone‐sensitive channels. The Desroziers method is used to diagnose observation error covariance matrix and estimate realistic ozone observation standard errors taking into account cross‐correlations between IASI channels. The background error covariance matrix for ozone is estimated using radiosondes. A control run assimilating 123 IASI operational channels is compared to an experiment which assimilates, in addition, 15 IASI ozone‐sensitive channels. Results show potential benefits of IASI ozone‐sensitive channels combined with realistic ozone from MOCAGE CTM to improve temperature, humidity and ozone analyses simultaneously. This work is an encouraging first step for the enhancing of the coupling between the global model ARPEGE and MOCAGE CTM.
Upward Frequency Sweeping Due to the Nonlinear Resonance of Multiwave Coupling and Its Significant Contribution to the Hall Effect at the Reconnection Point
Authors: Huang Fucheng , Feng Xueshang 
Published: October 2018

AbstractWe suggest a nonlinear resonance mechanism to explain how the Hall term predominates the convection term at the reconnection point during magnetic reconnection quantitatively. Both the case with guide field and that without guide field are run in this simulation. The new findings are as follows: (1) The Hall term compared to the convection term can reach the order of several tens with sharp peaks at the reconnection point in the former case. (2) The frequency range of electrostatic waves at the reconnection point in the former case is broader than that in the latter case. (3) The instantaneous frequency of x or z component of the Hall term can pulse instantly in the former case, and it can exceed the order of 10 in this case. The upward frequency sweeping due to the nonlinear resonance of multiwave coupling is inferred to be responsible for the above simulation results.
High Ice Purity of Martian Lobate Debris Aprons at the Regional Scale: Evidence From an Orbital Radar Sounding Survey in Deuteronilus and Protonilus Mensae
Authors: Petersen Eric Ivan , Holt John W. , Levy Joseph S. 
Published: October 2018

AbstractLobate Debris Aprons (LDA) are martian landforms with a strong morphologic resemblance to rock glaciers and debris‐covered glaciers. While the Shallow Radar (SHARAD) sounder has confirmed that a handful of LDA are composed of >80% water ice, viscous flow morphology can also be produced by as little as 30% ice. To distinguish between these endmembers, we conducted a comprehensive regional SHARAD survey of LDA, in Deuteronilus Mensae. We found that the majority of LDA are penetrated by SHARAD and determined that they are composed of a material with
and tanδ≈0.002 < 0.005. These LDA are thus consistently composed of >80% water ice, which constrains the regional sequestered ice budget to a minimum of 0.9 − 1.0 × 105 km3 or a 62–69‐cm Global Equivalent Layer.
Video Transects Reveal That Tidal Sand Waves Affect the Spatial Distribution of Benthic Organisms and Sand Ripples
Authors: Damveld J. H. , van der Reijden K. J. , Cheng C. , Koop L. , Haaksma L. R. , Walsh C. A. J. , Soetaert K. , Borsje B. W. , Govers L. L. , Roos P. C. , Olff H. , Hulscher S. J. M. H. 
Published: October 2018

AbstractThe sandy seabed of shallow coastal shelf seas displays morphological patterns of various dimensions. The seabed also harbors a rich ecosystem. Increasing pressure from human‐induced disturbances necessitates further study on drivers of benthic community distributions over morphological patterns. Moreover, a greater understanding of the sand ripple distribution over tidal sand waves may improve morphological model predictions. Here we analyzed the biotic abundance and ripple morphology in sand wave troughs and crests using video transects. We found that both the epibenthos and endobenthos are significantly more abundant in sand wave troughs, where ripples are less abundant and more irregularly shaped. Finally, we show that camera systems are relatively quick and effective tools to study biotic spatial patterns in relation to seabed morphology.
Global Assessment of Supraglacial Debris‐Cover Extents
Authors: Scherler Dirk , Wulf Hendrik , Gorelick Noel 
Published: October 2018

AbstractRocky debris on glacier surfaces influences ice melt rates and the response of glaciers to climate change. However, scarce data on the extent and evolution of supraglacial debris cover have so far limited its inclusion in regional to global glacier models. Here we present global data sets of supraglacial debris‐cover extents, based on Landsat 8 and Sentinel‐2 optical satellite imagery. We find that about 4.4% (~26,000 km2) of all glacier areas (excluding the Greenland ice sheet and Antarctica) are covered with debris, but that the distribution is heterogeneous. The largest debris‐covered areas are located in high‐mountain ranges, away from the poles. At a global scale, we find a negative scaling relationship between glacier size and percentage of debris. Therefore, the influence of debris cover on glacier mass balances is expected to increase in the future, as glaciers continue to shrink.
Energetic Electron Precipitation Associated With Pulsating Aurora Observed by VLF Radio Propagation During the Recovery Phase of a Substorm on 27 March 2017
Authors: Tsuchiya F. , Hirai A. , Obara T. , Misawa H. , Kurita S. , Miyoshi Y. , Shiokawa K. , Connors M. , Ozaki M. , Kasahara Y. , Kumamoto A. , Kasaba Y. , Matsuoka A. , Shoji M. , Shinohara I. 
Published: October 2018

AbstractRecent studies suggest that electrons with energies up to several hundred keV precipitate into the atmosphere associated with pulsating aurora (PsA). It is debated the highest energy of precipitating electrons associated with PsA. Here we report for the first time that the energy extends to relativistic energies. PsA was observed by THEMIS all‐sky imagers during a substorm that occurred on 27 March 2017. Energetic electron precipitation was detected by very low frequency subionospheric propagation. We found similar time variations between the auroral intensity and perturbation of the received radio signal intensity when the PsA occurred on the radio path. The perturbation showed a short recovery time of ~2 s. The recovery time indicates relaxation from ionospheric modification due to energetic electron precipitation and depends on the stopping altitude of the electrons. The recovery time required a stopping altitude of 50–60 km and indicates that the PsA is accompanied by relativistic electron precipitation.
Estimated Heat Budget During Summer Melt of Arctic First‐Year Sea Ice
Authors: Skyllingstad Eric D. , Polashenski Chris 
Published: October 2018

AbstractMelt ponds on summer Arctic sea ice control surface albedo, governing energy and mass balance of the ice. The date ponds first form has been connected to interannual variations in ice retreat. Here we evaluate the surface energy balance that governs this critical pond formation date. A three‐dimensional sea ice model with resolved melt ponds is used to diagnose pond onset date at a coastal site across years with observed surface fluxes but incomplete pond observations. Results show that the combined sensible and latent heat flux is the best predictor of pond formation date. This finding supports the hypothesis that synoptic weather events transporting warm, moist air into the Arctic are key to initiating pond formation, triggering albedo feedbacks, and, by extension, ice retreat. Changes in timing and frequency of spring warm air incursions may have significant implications on the ice cover and provide predictive power over seasonal ice retreat.
Mapping Ice Algal Blooms in Southwest Greenland From Space
Authors: Wang Shujie , Tedesco Marco , Xu Min , Alexander Patrick M. 
Published: October 2018

AbstractQuantifying the distribution and abundance of ice algae is fundamental for understanding the evolving processes of algal blooms in supraglacial environments, particularly over the Greenland ice sheet, given the role of algal impurities in modulating surface albedo and meltwater production. Field observations of ice algae in Greenland are very limited over space and time. Here we show for the first time the regional variability in algal abundance across the dark zone in southwest Greenland, derived from Sentinel‐3 images acquired during the summertime in 2016 and 2017. We demonstrate the capacity of Sentinel‐3 imagery to characterize the spatial pattern of algal abundance using the reflectance ratios between 709‐ and 673‐nm bands, highly consistent with field measurements. The estimated algal abundance reveals a significant linear growth pattern of algal population with time after the peak of dark ice presence, shown to be tightly linked to surface runoff and meltwater production.
Field Observations of Turbulence, Sand Suspension, and Cross‐Shore Transport Under Spilling and Plunging Breakers
Authors: Aagaard Troels , Hughes Michael G. , Ruessink Gerben 
Published: October 2018

AbstractMeasurements of wave orbital velocity, near‐bed turbulence levels, and sediment suspension were obtained under plunging and spilling breakers in the outer surf zone on the beach at Vejers, Denmark. For the same range of relative wave heights and indicators of wave nonlinearity, we observed significantly larger suspended sediment concentrations and onshore‐directed rates of suspended sediment transport under (long period) plunging breakers, compared to (short period) spilling breakers. This is consistent with the long‐held understanding that, for a given beach slope, onshore transport and beach accretion are associated with longer‐period waves and offshore transport and erosion are associated with shorter‐period waves. An intra‐wave analysis of hydrodynamics and sediment suspension revealed that the main reason for the larger suspended sediment transport rates under plunging waves was (i) larger time‐averaged suspended sediment loads under plunging waves, and (ii) a larger difference in cumulated sediment load under the wave crest phase compared to the wave trough phase for plunging breakers. This latter difference was due to an earlier arrival at the seabed of higher levels of turbulent kinetic energy under plunging waves compared to spilling waves. Hence, both magnitude and timing within the wave cycle of turbulent kinetic energy production are important in a quantification of sediment transport under breaking waves. For ensemble‐averaged intense suspension events, contributing roughly 50% of the total sediment suspension during individual records, we found that instantaneous near‐bed sediment load was linearly related to instantaneous levels of Froude‐scaled turbulent kinetic energy.
Sensitivity of the Simulated Tropical Cyclone Intensification to the Boundary‐Layer Height Based on a K‐Profile Boundary‐Layer Parameterization Scheme
Authors: Ma Zhanhong , Fei Jianfang , Huang Xiaogang , Cheng Xiaoping 
Published: October 2018

AbstractThe sensitivity of simulated tropical cyclone intensification to the boundary‐layer height is investigated in this study, using the Yonsei University (YSU) scheme to parameterize boundary‐layer processes. Results reveal nonlinear effects of the boundary‐layer height on the intensification of simulated tropical cyclones. For shallow boundary layer (e.g., below 1,000 m), the storm intensification is sensitive to the depth of the boundary layer; decreasing the boundary‐layer height would lead to a progressive increase in the intensification. For deep boundary layer, the storm intensification is weakly affected by the boundary‐layer height. The roles of unbalanced processes are primarily responsible for these discrepancies. The frictional dissipation is confined in a relatively thin layer for shallow boundary layer, and decreasing the boundary‐layer height causes a larger extent of gradient wind imbalance and stronger radial inflow in the boundary layer. As a consequence, the unbalanced flow effects are more pronounced and contribute to a more rapidly intensifying tropical cyclone. The vertical mixing is intense in a deep boundary layer, resulting in weak unbalanced processes; therefore, further enhancing the boundary‐layer height has less appreciable influence on the tropical cyclone intensification than that in a shallow boundary layer. Increasing the boundary‐layer height has also consequences of drying and warming the lower part of the boundary layer while moistening and cooling the atmosphere aloft, which may be favorable for encouraging outer‐core convection activities. These results underscore the importance of accurately estimating the boundary‐layer height in a K‐profile boundary‐layer scheme for tropical cyclone simulations.
Time Domain Simulation of Geomagnetically Induced Current (GIC) Flowing in 500‐kV Power Grid in Japan Including a Three‐Dimensional Ground Inhomogeneity
Authors: Nakamura S. , Ebihara Y. , Fujita S. , Goto T. , Yamada N. , Watari S. , Omura Y. 
Published: October 2018

AbstractWe performed 3‐D time domain simulation of geomagnetically induced currents (GICs) flowing in the Japanese 500‐kV power grid. The three‐dimensional distribution of the geomagnetically induced electric field (GIE) was calculated by using the finite difference time domain method with a three‐dimensional electrical conductivity model constructed from a global relief model and a global map of sediment thickness. First, we imposed a uniform sheet current at 100‐km altitude with a sinusoidal perturbation to illuminate the influence of the structured ground conductivity on GIE and GIC. The simulation result shows that GIE exhibits localized, uneven distribution that can be attributed to charge accumulation due to the inhomogeneous conductivity below the Earth's surface. The charge accumulation becomes large when the conductivity gradient vector is parallel or antiparallel to the incident electric field. For given GIE, we calculated the GICs flowing in a simplified 500‐kV power grid network in Japan. The influence of the inhomogeneous ground conductivity on GIC appears to depend on a combination of the location of substations and the direction of the source current. Uneven distribution of the power grid system gives rise to intensification of the GICs flowing in remote areas where substations/power plants are distributed sparsely. Second, we imposed the sheet current with its intensity inferred from the ground magnetic disturbance for the magnetic storm of 27 May 2017. We compared the calculated GICs with the observed ones at substations around Tokyo and found a certain agreement when the uneven distribution of GIE is incorporated with the simulation.
Genome-wide association study of brain amyloid deposition as measured by Pittsburgh Compound-B (PiB)-PET imaging
Authors:   for the Alzheimer’s Disease Neuroimaging Initiative (ADNI), Yan Qi , Nho Kwangsik , Del-Aguila Jorge L. , Wang Xingbin , Risacher Shannon L. , Fan Kang-Hsien , Snitz Beth E. , Aizenstein Howard J. , Mathis Chester A. , Lopez Oscar L. , Demirci F. Yesim , Feingold Eleanor , Klunk William E. , Saykin Andrew J. , Cruchaga Carlos , Kamboh M. Ilyas 
Published: October 2018

AbstractDeposition of amyloid plaques in the brain is one of the two main pathological hallmarks of Alzheimer’s disease (AD). Amyloid positron emission tomography (PET) is a neuroimaging tool that selectively detects in vivo amyloid deposition in the brain and is a reliable endophenotype for AD that complements cerebrospinal fluid biomarkers with regional information. We measured in vivo amyloid deposition in the brains of ~1000 subjects from three collaborative AD centers and ADNI using 11C-labeled Pittsburgh Compound-B (PiB)-PET imaging followed by meta-analysis of genome-wide association studies, first to our knowledge for PiB-PET, to identify novel genetic loci for this endophenotype. The APOE region showed the most significant association where several SNPs surpassed the genome-wide significant threshold, with APOE*4 being most significant (P-meta = 9.09E-30; β = 0.18). Interestingly, after conditioning on APOE*4, 14 SNPs remained significant at P < 0.05 in the APOE region that were not in linkage disequilibrium with APOE*4. Outside the APOE region, the meta-analysis revealed 15 non-APOE loci with P < 1E-05 on nine chromosomes, with two most significant SNPs on chromosomes 8 (P-meta = 4.87E-07) and 3 (P-meta = 9.69E-07). Functional analyses of these SNPs indicate their potential relevance with AD pathogenesis. Top 15 non-APOE SNPs along with APOE*4 explained 25–35% of the amyloid variance in different datasets, of which 14–17% was explained by APOE*4 alone. In conclusion, we have identified novel signals in APOE and non-APOE regions that affect amyloid deposition in the brain. Our data also highlights the presence of yet to be discovered variants that may be responsible for the unexplained genetic variance of amyloid deposition.
Autophagy modulates temozolomide-induced cell death in alveolar Rhabdomyosarcoma cells
Authors: Moghadam Adel Rezaei , da Silva Rosa Simone C. , Samiei Ehsan , Alizadeh Javad , Field Jared , Kawalec Philip , Thliveris James , Akbari Mohsen , Ghavami Saeid , Gordon Joseph W. 
Published: October 2018

AbstractRhabdomyosarcoma (RMS) is a muscle-derived tumor. In both pre-clinical and clinical studies Temozolomide (TMZ) has been recently tested against RMS; however, the precise mechanism of action of TMZ in RMS remains unclear. Here we demonstrate that TMZ decreases the cell viability of the RH30 RMS and C2C12 cell line, where cells display evidence of mitochondrial outer membrane permeability. Interestingly, the C2C12 mouse myoblast line was relatively more resistant to TMZ-induced apoptosis. Moreover, we observed that TMZ activated biochemical and morphological markers of autophagy in both cell lines. Autophagy inhibition in both RH30 and C2C12 cells significantly increased TMZ-induced cell death. In RH30 cells, TMZ increased Mcl-1 and Bax protein expression compared to corresponding time match controls while in C2C12 Mcl-1, Bcl-2, Bcl-XL, and Bax protein expression were not changed. Baf-A1 co-treatment with TMZ significantly decrease Mcl-1 expression compared to TMZ while increase Bax expression in C2C12 cells (Bcl2 and Bcl-XL do not significantly change in Baf-A1/TMZ co-treatment). Using a three-dimensional (3D) C2C12 and RH30 culture model we demonstrated that TMZ is significantly more toxic in RH30 cells (live/dead assay). Additionally, we have observed in our 3D culture model that TMZ induced both apoptosis (cleavage of PARP) and autophagy (LC3-puncta and localization of LC3/p62). Therefore, our data demonstrate that TMZ induces simultaneous autophagy and apoptosis in both RH30 and C2C12 cells in 2D and 3D culture model, where RH30 cells are more sensitive to TMZ-induced death. Furthermore, autophagy serves to protect RH30 cells from TMZ-induced death.
Lévy-like movement patterns of metastatic cancer cells revealed in microfabricated systems and implicated in vivo
Authors: Huda Sabil , Weigelin Bettina , Wolf Katarina , Tretiakov Konstantin V. , Polev Konstantin , Wilk Gary , Iwasa Masatomo , Emami Fateme S. , Narojczyk Jakub W. , Banaszak Michal , Soh Siowling , Pilans Didzis , Vahid Amir , Makurath Monika , Friedl Peter , Borisy Gary G. , Kandere-Grzybowska Kristiana , Grzybowski Bartosz A. 
Published: October 2018

AbstractMetastatic cancer cells differ from their non-metastatic counterparts not only in terms of molecular composition and genetics, but also by the very strategy they employ for locomotion. Here, we analyzed large-scale statistics for cells migrating on linear microtracks to show that metastatic cancer cells follow a qualitatively different movement strategy than their non-invasive counterparts. The trajectories of metastatic cells display clusters of small steps that are interspersed with long “flights”. Such movements are characterized by heavy-tailed, truncated power law distributions of persistence times and are consistent with the Lévy walks that are also often employed by animal predators searching for scarce prey or food sources. In contrast, non-metastatic cancerous cells perform simple diffusive movements. These findings are supported by preliminary experiments with cancer cells migrating away from primary tumors in vivo. The use of chemical inhibitors targeting actin-binding proteins allows for “reprogramming” the Lévy walks into either diffusive or ballistic movements.
Establishing the effects of mesoporous silica nanoparticle properties on in vivo disposition using imaging-based pharmacokinetics
Authors: Dogra Prashant , Adolphi Natalie L. , Wang Zhihui , Lin Yu-Shen , Butler Kimberly S. , Durfee Paul N. , Croissant Jonas G. , Noureddine Achraf , Coker Eric N. , Bearer Elaine L. , Cristini Vittorio , Brinker C. Jeffrey 
Published: October 2018

AbstractThe progress of nanoparticle (NP)-based drug delivery has been hindered by an inability to establish structure-activity relationships in vivo. Here, using stable, monosized, radiolabeled, mesoporous silica nanoparticles (MSNs), we apply an integrated SPECT/CT imaging and mathematical modeling approach to understand the combined effects of MSN size, surface chemistry and routes of administration on biodistribution and clearance kinetics in healthy rats. We show that increased particle size from ~32- to ~142-nm results in a monotonic decrease in systemic bioavailability, irrespective of route of administration, with corresponding accumulation in liver and spleen. Cationic MSNs with surface exposed amines (PEI) have reduced circulation, compared to MSNs of identical size and charge but with shielded amines (QA), due to rapid sequestration into liver and spleen. However, QA show greater total excretion than PEI and their size-matched neutral counterparts (TMS). Overall, we provide important predictive functional correlations to support the rational design of nanomedicines.