bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effects of Inductive Electric Field on the Spatial and Temporal Evolution of the Inner Magnetospheric Ring Current
Authors: Liu Jianghuai , Ilie Raluca 
Published: February 2021

AbstractCharged particles are observed to be injected into the inner magnetosphere from the plasma sheet and energized up to high energies over short distance and time, during both geomagnetic storms and substorms. Numerous studies suggest that it is the short‐duration and high‐speed plasma flows, which are closely associated with the global effects of magnetic reconnection and inductive effects, rather than the slow and steady convection that control the earthward transport of plasma and magnetic flux from the magnetotail, especially during geomagnetic activities. In order to include the effect of the inductive electric field produced by the temporal change of magnetic field on the dynamics of ring current, we implemented both theoretical and numerical modifications to an inner magnetosphere kinetic model—Hot Electron‐Ion Drift Integrator. New drift terms associated with the inductive electric field are incorporated into the calculation of bounce‐averaged coefficients for the distribution function, and their numerical implementations and the associated effects on total drift and energization rate are discussed. Numerical simulations show that the local particle drifts are significantly altered by the presence of inductive electric fields, in addition to the changing magnetic gradient‐curvature drift due to the distortion of magnetic field, and at certain locations, the inductive drift dominates both the potential and the magnetic gradient‐curvature drift. The presence of a self‐consistent inductive electric field alters the overall particle trajectories, energization, and pitch angle, resulting in significant changes in the topology and the strength of the ring current.
On the Generation of an Unseasonal EPB Over South East Asia
Authors: Currie J. L. , Carter B. A. , Retterer J. , Dao T. , Pradipta R. , Caton R. , Groves K. , Otsuka Y. , Yokoyama T. , Hozumi K. , Le Truong T. , Terkildsen M. 
Published: February 2021

AbstractAn unseasonal equatorial plasma bubble (EPB) event over South‐East Asia was observed on July 22, 2014 that has not been studied before. An investigation into this event is presented with the 26th July, 2014 as a comparison, non‐bubble day. The 22nd July EPB event occurred in the late post‐sunset sector and was associated with a small upward plasma drift. This event was highlighted using a new filter on the SCINDA S4 data. Ionosonde data show that sporadic E was present during the growth period for the EPB event. Modeling results from Thermosphere‐Ionosphere Electrodynamics (TEC) Global Circulation Model were used to conduct a numerical experiment investigating the direct effect of sporadic E on the linear R‐T growth rate. It was shown that sporadic E located in the correct latitude and local time can increase the linear growth rate. The seeding conditions were investigated using TEC data from Patumwan, Thailand. Wave‐like structures were observed for both days of interest, with larger amplitudes on 22nd July compared with the 26th July. Finally, simulations using the high‐resolution model PBMOD showed that for forcing from above conditions similar to the days of interest, EPBs would form in the presence of large seed perturbations. Therefore, it is likely that this unseasonal event was caused by large seed perturbations in TEC.
Automatic Detection of the Thermal Electron Density From the WHISPER Experiment Onboard CLUSTER‐II Mission With Neural Networks
Authors: Gilet N. , De Leon E. , Gallé R. , Vallières X. , Rauch J.‐L. , Jegou K. , Bucciantini L. , Savreux V. , Décréau P. , Henri P. 
Published: February 2021

AbstractThe Waves of HIgh frequency and Sounder for Probing Electron density by Relaxation (WHISPER) instrument has been monitoring the bulk properties of the plasma environment around Earth for more than 20 years. Onboard the 3‐D Earth magnetospheric CLUSTER‐II mission, this experiment delivers active and natural electric field spectra, in a frequency interval ranging respectively from 3.5 to 82 kHz, and from 2 to 80 kHz. The thermal electron density, a key parameter of scientific interest and major driver for the calibration of particles instrument, is derived from spectra. Until recently, the extraction of the thermal electron density required a manual intervention. To automate this process, self‐learning algorithms based on Multilayer Neural Networks have been implemented. The evaluation of the thermal electron density from WHISPER spectra depends on the plasma region encountered by the spacecraft. First, a fully connected neural network has been implemented to predict the plasma region, using only the active spectra measured by the WHISPER instrument. Second, a specific neural network has been implemented to predict the thermal electron density for each plasma region. The model reaches up to 98% prediction accuracy for some plasma regimes. Two thermal electron density prediction models were trained, a first one to process data from the free solar wind and magnetosheath regions, and a second one for the plasmasphere region. The prediction accuracy can reach up to 95% in the free solar wind and magnetosheath regimes, and 75% in the plasmasphere.
Seismic Structure, Gravity Anomalies and Flexure Along the Emperor Seamount Chain
Authors: Watts A. B. , Grevemeyer I. , Shillington D. J. , Dunn R. A. , Boston B. , Gómez de la Peña L. 
Published: February 2021

AbstractThe Hawaiian‐Emperor seamount chain in the Pacific Ocean has provided fundamental insights into hotspot generated intraplate volcanism and the long‐term strength of oceanic lithosphere. However, only a few seismic experiments to determine crustal and upper mantle structure have been carried out on the Hawaiian Ridge, and no deep imaging has ever been carried out along the Emperor seamounts. Here, we present the results of an active source seismic experiment using 29 Ocean‐Bottom Seismometers (OBS) carried out along a strike profile of the seamounts in the region of Jimmu and Suiko guyots. Joint reflection and refraction tomographic inversion of the OBS data show the upper crust is highly heterogeneous withPwave velocities <4–5 km s−1, which are attributed to extrusive lavas and clastics. In contrast, the lower crust is remarkably homogeneous with velocities of 6.5–7.2 km s−1, which we attribute to oceanic crust and mafic intrusions. Moho is identified by a strongPmParrival at offsets of 20–80 km, yielding depths of 13–16 km. The underlying mantle is generally homogeneous with velocities in the range 7.9–8.0 km s−1. The crust and mantle velocity structure has been verified by gravity modeling. While top of oceanic crust prior to volcano loading is not recognized as a seismic or gravity discontinuity, flexural modeling reveals a ∼5.0–5.5 km thick preexisting oceanic crust that is overlain by a ∼8 km thick volcanic edifice. Unlike at the Hawaiian Ridge, we find no evidence of magmatic underplating.
A Two‐Phase Model for the Evolution of Planetary Embryos With Implications for the Formation of Mars
Authors: Zhang Zhongtian , Bercovici David , Jordan Jacob S. 
Published: February 2021

AbstractAttempts to constrain the accretion history of Mars using geochemical observations have focused on the chronology of core formation. However, given the possibility of incomplete metal‐silicate equilibration, most previous results cannot distinguish between the following two scenarios: (1) Mars was formed early through gradual accretion and remained isolated as a “planetary embryo” and (2) Mars underwent relatively protracted accretion involving collisions between planetary embryos. Here we use a two‐phase model to demonstrate that, despite strong heating from the short‐lived radionuclide 26Al, the mantle of a Mars‐sized planetary embryo may stay effectively solid because the generation and migration of melts in relatively small fractions leads to efficient heat transport. In this scenario, the effectively solid mantle would have undergone substantial differentiation before the extinction of 26Al, and the disparate planetary building blocks would not have been homogenized within the embryo. Hence, features of very early silicate differentiation (within the first few million years of the solar system) and significant nucleosynthetic isotope heterogeneity would be expected to exist in stranded planetary embryos. In contrast, meteorite observations suggest that the crust‐mantle system of Mars is homogeneous in nucleosynthetic isotope anomalies and the onset of silicate differentiation was no earlier than ∼15 Myr after solar system formation. This discrepancy implies that Mars is not a stranded planetary embryo. Instead, we suggest that the accretion of Mars involved at least one collision between planetary embryos with comparable sizes that caused complete melting and homogenization during the giant‐impact stage of planetary growth.
Why are ELEvoHI CME Arrival Predictions Different if Based on STEREO‐A or STEREO‐B Heliospheric Imager Observations?
Authors: Hinterreiter Jürgen , Amerstorfer Tanja , Reiss Martin A. , Möstl Christian , Temmer Manuela , Bauer Maike , Amerstorfer Ute V. , Bailey Rachel L. , Weiss Andreas J. , Davies Jackie A. , Barnard Luke A. , Owens Mathew J. 
Published: February 2021

AbstractAccurate forecasting of the arrival time and arrival speed of coronal mass ejections (CMEs) is an unsolved problem in space weather research. In this study, a comparison of the predicted arrival times and speeds for each CME based, independently, on the inputs from the two STEREO vantage points is carried out. We perform hindcasts using ELlipse Evolution model based on Heliospheric Imager observations (ELEvoHI) ensemble modeling. An estimate of the ambient solar wind conditions is obtained by the Wang‐Sheeley‐Arge/Heliospheric Upwind eXtrapolation (WSA/HUX) model combination that serves as input to ELEvoHI. We carefully select 12 CMEs between February 2010 and July 2012 that show clear signatures in both STEREO‐A and STEREO‐B HI time‐elongation maps, that propagate close to the ecliptic plane, and that have corresponding in situ signatures at Earth. We find a mean arrival time difference of 6.5 h between predictions from the two different viewpoints, which can reach up to 9.5 h for individual CMEs, while the mean arrival speed difference is 63 km s−1. An ambient solar wind with a large speed variance leads to larger differences in the STEREO‐A and STEREO‐B CME arrival time predictions (cc = 0.92). Additionally, we compare the predicted arrivals, from both spacecraft, to the actual in situ arrivals at Earth and find a mean absolute error of 7.5 ± 9.5 h for the arrival time and 87 ± 111 km s−1 for the arrival speed. There is no tendency for one spacecraft to provide more accurate arrival predictions than the other.
The electrochemical detection of bioterrorism agents: a review of the detection, diagnostics, and implementation of sensors in biosafety programs for Class A bioweapons
Authors: O’Brien Connor , Varty Kathleen , Ignaszak Anna 
Published: February 2021

AbstractDuring the past year, disease has shown us the iron grip it can hold over a population of people. Health systems can be overwhelmed, economies can be brought into recession, and many people can be harmed or killed. When weaponized, diseases can be manipulated to create a detriment to health while becoming an economic burden on any society. It is consequently prudent that easy detection of bioweapons is available to governments for protecting their people. Electrochemical sensing displays many distinct advantages, such as its low limit of detection, low cost to run, rapid generation of results, and in many instances portability. We therefore present a wide array of electrochemical sensing platforms currently being fabricated, a brief summary of Class A bioweapons, and the potential future of bioweapon detection and biosafety.
Whole-exome mutational landscape of neuroendocrine carcinomas of the gallbladder
Authors: Liu Fatao , Li Yongsheng , Ying Dongjian , Qiu Shimei , He Yong , Li Maolan , Liu Yun , Zhang Yijian , Zhu Qin , Hu Yunping , Liu Liguo , Li Guoqiang , Pan Weihua , Jin Wei , Mu Jiasheng , Cao Yang , Liu Yingbin 
Published: February 2021

AbstractNeuroendocrine carcinoma (NEC) of the gallbladder (GB-NEC) is a rare but extremely malignant subtype of gallbladder cancer (GBC). The genetic and molecular signatures of GB-NEC are poorly understood; thus, molecular targeting is currently unavailable. In the present study, we applied whole-exome sequencing (WES) technology to detect gene mutations and predicted somatic single-nucleotide variants (SNVs) in 15 cases of GB-NEC and 22 cases of general GBC. In 15 GB-NECs, the C > T mutation was predominant among the 6 types of SNVs. TP53 showed the highest mutation frequency (73%, 11/15). Compared with neuroendocrine carcinomas of other organs, significantly mutated genes (SMGs) in GB-NECs were more similar to those in pulmonary large-cell neuroendocrine carcinomas (LCNECs), with driver roles for TP53 and RB1. In the COSMIC database of cancer-related genes, 211 genes were mutated. Strikingly, RB1 (4/15, 27%) and NAB2 (3/15, 20%) mutations were found specifically in GB-NECs; in contrast, mutations in 29 genes, including ERBB2 and ERBB3, were identified exclusively in GBC. Mutations in RB1 and NAB2 were significantly related to downregulation of the RB1 and NAB2 proteins, respectively, according to immunohistochemical (IHC) data (p values = 0.0453 and 0.0303). Clinically actionable genes indicated 23 mutated genes, including ALK, BRCA1, and BRCA2. In addition, potential somatic SNVs predicted by ISOWN and SomVarIUS constituted 6 primary COSMIC mutation signatures (1, 3, 30, 6, 7, and 13) in GB-NEC. Genes carrying somatic SNVs were enriched mainly in oncogenic signaling pathways involving the Notch, WNT, Hippo, and RTK-RAS pathways. In summary, we have systematically identified the mutation landscape of GB-NEC, and these findings may provide mechanistic insights into the specific pathogenesis of this deadly disease.
Cognitive reflection correlates with behavior on Twitter
Authors: Mosleh Mohsen , Pennycook Gordon , Arechar Antonio A. , Rand David G. 
Published: February 2021

AbstractWe investigate the relationship between individual differences in cognitive reflection and behavior on the social media platform Twitter, using a convenience sample ofN = 1,901 individuals from Prolific. We find that people who score higher on the Cognitive Reflection Test—a widely used measure of reflective thinking—were more discerning in their social media use, as evidenced by the types and number of accounts followed, and by the reliability of the news sources they shared. Furthermore, a network analysis indicates that the phenomenon of echo chambers, in which discourse is more likely with like-minded others, is not limited to politics: people who scored lower in cognitive reflection tended to follow a set of accounts which are avoided by people who scored higher in cognitive reflection. Our results help to illuminate the drivers of behavior on social media platforms and challenge intuitionist notions that reflective thinking is unimportant for everyday judgment and decision-making.
Dissociable roles of cortical excitation-inhibition balance during patch-leaving versus value-guided decisions
Authors: Kaiser Luca F. , Gruendler Theo O. J. , Speck Oliver , Luettgau Lennart , Jocham Gerhard 
Published: February 2021

AbstractIn a dynamic world, it is essential to decide when to leave an exploited resource. Such patch-leaving decisions involve balancing the cost of moving against the gain expected from the alternative patch. This contrasts with value-guided decisions that typically involve maximizing reward by selecting the current best option. Patterns of neuronal activity pertaining to patch-leaving decisions have been reported in dorsal anterior cingulate cortex (dACC), whereas competition via mutual inhibition in ventromedial prefrontal cortex (vmPFC) is thought to underlie value-guided choice. Here, we show that the balance between cortical excitation and inhibition (E/I balance), measured by the ratio of GABA and glutamate concentrations, plays a dissociable role for the two kinds of decisions. Patch-leaving decision behaviour relates to E/I balance in dACC. In contrast, value-guided decision-making relates to E/I balance in vmPFC. These results support mechanistic accounts of value-guided choice and provide evidence for a role of dACC E/I balance in patch-leaving decisions.
The docking of synaptic vesicles on the presynaptic membrane induced by α-synuclein is modulated by lipid composition
Authors: Man Wing K. , Tahirbegi Bogachan , Vrettas Michail D. , Preet Swapan , Ying Liming , Vendruscolo Michele , De Simone Alfonso , Fusco Giuliana 
Published: February 2021

Abstractα-Synuclein (αS) is a presynaptic disordered protein whose aberrant aggregation is associated with Parkinson’s disease. The functional role of αS is still debated, although it has been involved in the regulation of neurotransmitter release via the interaction with synaptic vesicles (SVs). We report here a detailed characterisation of the conformational properties of αS bound to the inner and outer leaflets of the presynaptic plasma membrane (PM), using small unilamellar vesicles. Our results suggest that αS preferentially binds the inner PM leaflet. On the basis of these studies we characterise in vitro a mechanism by which αS stabilises, in a concentration-dependent manner, the docking of SVs on the PM by establishing a dynamic link between the two membranes. The study then provides evidence that changes in the lipid composition of the PM, typically associated with neurodegenerative diseases, alter the modes of binding of αS, specifically in a segment of the sequence overlapping with the non-amyloid component region. Taken together, these results reveal how lipid composition modulates the interaction of αS with the PM and underlie its functional and pathological behaviours in vitro.
Cavin1 intrinsically disordered domains are essential for fuzzy electrostatic interactions and caveola formation
Authors: Tillu Vikas A. , Rae James , Gao Ya , Ariotti Nicholas , Floetenmeyer Matthias , Kovtun Oleksiy , McMahon Kerrie-Ann , Chaudhary Natasha , Parton Robert G. , Collins Brett M. 
Published: February 2021

AbstractCaveolae are spherically shaped nanodomains of the plasma membrane, generated by cooperative assembly of caveolin and cavin proteins. Cavins are cytosolic peripheral membrane proteins with negatively charged intrinsically disordered regions that flank positively charged α-helical regions. Here, we show that the three disordered domains of Cavin1 are essential for caveola formation and dynamic trafficking of caveolae. Electrostatic interactions between disordered regions and α-helical regions promote liquid-liquid phase separation behaviour of Cavin1 in vitro, assembly of Cavin1 oligomers in solution, generation of membrane curvature, association with caveolin-1, and Cavin1 recruitment to caveolae in cells. Removal of the first disordered region causes irreversible gel formation in vitro and results in aberrant caveola trafficking through the endosomal system. We propose a model for caveola assembly whereby fuzzy electrostatic interactions between Cavin1 and caveolin-1 proteins, combined with membrane lipid interactions, are required to generate membrane curvature and a metastable caveola coat.
A pediatric brain tumor atlas of genes deregulated by somatic genomic rearrangement
Authors: Zhang Yiqun , Chen Fengju , Donehower Lawrence A. , Scheurer Michael E. , Creighton Chad J. 
Published: February 2021

AbstractThe global impact of somatic structural variants (SSVs) on gene expression in pediatric brain tumors has not been thoroughly characterised. Here, using whole-genome and RNA sequencing from 854 tumors of more than 30 different types from the Children’s Brain Tumor Tissue Consortium, we report the altered expression of hundreds of genes in association with the presence of nearby SSV breakpoints. SSV-mediated expression changes involve gene fusions, altered cis-regulation, or gene disruption. SSVs considerably extend the numbers of patients with tumors somatically altered for critical pathways, including receptor tyrosine kinases (KRAS, MET, EGFR, NF1), Rb pathway (CDK4), TERT, MYC family (MYC, MYCN, MYB), and HIPPO (NF2). Compared to initial tumors, progressive or recurrent tumors involve a distinct set of SSV-gene associations. High overall SSV burden associates with TP53 mutations, histone H3.3 gene H3F3C mutations, and the transcription of DNA damage response genes. Compared to adult cancers, pediatric brain tumors would involve a different set of genes with SSV-altered cis-regulation. Our comprehensive and pan-histology genomic analyses reveal SSVs to play a major role in shaping the transcriptome of pediatric brain tumors.
Ni-catalyzed regio- and stereo-defined intermolecular cross-electrophile dialkylation of alkynes without directing group
Authors: Zhan Yi-Zhou , Xiao Nan , Shu Wei 
Published: February 2021

AbstractThe development of straightforward synthesis of regio- and stereodefined alkenes with multiple aliphatic substituents under mild conditions is an unmet challenge owing to competitive β-hydride elimination and selectivity issues. Herein, we report the nickel-catalyzed intermolecular cross-dialkylation of alkynes devoid of directing or activating groups to afford multiple aliphatic substituted alkenes in a syn-selective fashion at room temperature. The combination of two-electron oxidative cyclometallation and single-electron cross-electrophile coupling of nickel enables the syn-cross-dialkylation of alkynes at room temperature. This reductive protocol enables the sequential installation of two different alkyl substituents onto alkynes in a regio- and stereo-selective manner, circumventing the tedious preformation of sensitive organometallic reagents. The synthetic utility of this protocol is demonstrated by efficient synthesis of multi-substituted unfunctionalized alkenes and diverse transformations of the product.
Combined quantum tunnelling and dielectrophoretic trapping for molecular analysis at ultra-low analyte concentrations
Authors: Tang Longhua , Nadappuram Binoy Paulose , Cadinu Paolo , Zhao Zhiyu , Xue Liang , Yi Long , Ren Ren , Wang Jiangwei , Ivanov Aleksandar P. , Edel Joshua B. 
Published: February 2021

AbstractQuantum tunnelling offers a unique opportunity to study nanoscale objects with atomic resolution using electrical readout. However, practical implementation is impeded by the lack of simple, stable probes, that are required for successful operation. Existing platforms offer low throughput and operate in a limited range of analyte concentrations, as there is no active control to transport molecules to the sensor. We report on a standalone tunnelling probe based on double-barrelled capillary nanoelectrodes that do not require a conductive substrate to operate unlike other techniques, such as scanning tunnelling microscopy. These probes can be used to efficiently operate in solution environments and detect single molecules, including mononucleotides, oligonucleotides, and proteins. The probes are simple to fabricate, exhibit remarkable stability, and can be combined with dielectrophoretic trapping, enabling active analyte transport to the tunnelling sensor. The latter allows for up to 5-orders of magnitude increase in event detection rates and sub-femtomolar sensitivity.