bluuebunny/crossref_metadata_2025_split huggingface dataset:
On The Possibility of Identification of the Moving Celestial Objects Observed with the Space Astrometric Telescope
Authors: Bykov O.P. 
Published: June 2021

In connection with the creation of the scientific grounds of the Russian Project named “Struve” Space Astrometric System, the main principles of classification and identification of any celestial moving object observed with this System were formulated and basic algorithms were elaborated. These algorithms are invariable for a short or long observational arc, for a known or unknown heavenly body and for an artificial or natural celestial object.For classification of observed celestial bodies the angular velocities of motion are used. These values are calculated from the statistical treatment of the 5 nearest spherical celestial body positions with a time intervalbetween them near 7 seconds.For an identification of well known sky objects ordinary procedure may be used by means of traditional ephemeris calculations. For an identification of unknown natural celestial bodies a special algorithm was developed. Ituses a calculated angular velocity of moving object from one scan to another close scan of observations. Then, having several accurate positions of fixed object during 5-10 hours per day, we can determine an initial elliptical object’s orbit by the Apparent Motion Parameters Method created at Pulkovo Observatory. It deals with a position of object, its angular velocity and acceleration, position’s angle and a curvature of trajectory on a short observational arc. These last four quantities are named the Apparent Motion Parameters.In spite of a preliminary character of the AMP-method orbits we can identify an observed object through a large interval of time, for example over 2-4 months after orbit determination. In this problem the observed and calculated angular velocities of the object’s motion are very useful.
They are new and important ephemeris parameters at the epoch of Space Telescope astrometric positional observations. Examples of simulations of orbit determinations will be presented.
Dating the Great Divergence
Authors: Goldstone Jack A. 
Published: June 2021

AbstractNew data on Dutch and British GDP/capita show that at no time prior to 1750, perhaps not before 1800, did the leading countries of northwestern Europe enjoy sustained strong growth in GDP/capita. Such growth in income per head as did occur was highly episodic, concentrated in a few decades and then followed by long periods of stagnation of income per head. Moreover, at no time before 1800 did the leading economies of northwestern Europe reach levels of income per capita much different from peak levels achieved hundreds of years earlier in the most developed regions of Italy and China. When the Industrial Revolution began in Britain, it was not preceded by patterns of pre-modern income growth that were in any way remarkable, neither by sustained prior growth in real incomes nor exceptional levels of income per head. The Great Divergence, seen as the onset of sustained increases in income per head despite strong population growth, and achievement of incomes beyond pre-modern peaks, was a late occurrence, arising only from 1800.
Rapid Formation of an Ice Doline on Amery Ice Shelf, East Antarctica
Authors: Warner Roland C. , Fricker Helen A. , Adusumilli Susheel , Arndt Philipp , Kingslake Jonathan , Spergel Julian J. 
Published: June 2021

AbstractSurface meltwater accumulating on Antarctic ice shelves can drive fractures through to the ocean and potentially cause their collapse, leading to increased ice discharge from the continent. Implications of increasing surface melt for future ice shelf stability are inadequately understood. The southern Amery Ice Shelf has an extensive surface hydrological system, and we present data from satellite imagery and ICESat‐2 showing a rapid surface disruption there in winter 2019, covering ∼60 km2. We interpret this as an ice‐covered lake draining through the ice shelf, forming an ice doline with a central depression reaching 80 m depth amidst over 36 m uplift. Flexural rebound modeling suggests 0.75 km3 of water was lost. We observed transient refilling of the doline the following summer with rapid incision of a narrow meltwater channel (20 m wide and 6 m deep). This study demonstrates how high‐resolution geodetic measurements can explore critical fine‐scale ice shelf processes.
Wave Activity in a Dynamically Evolving Reconnection Separatrix
Authors: Holmes J. C. , Nakamura R. , Schmid D. , Nakamura T. K. M. , Roberts O. , Vörös Z. 
Published: June 2021

AbstractWaves driven by electron beams are frequently observed within the narrow separatrices of magnetic reconnection. Strong plasma instabilities can grow from mixing between the reconnection inflow and outflow, resulting in electron heating which ultimately influences the reconnection process. Observations of a separatrix encounter by the Magnetospheric MultiScale mission on July 11, 2017 feature an anti‐parallel electron beam accelerated in a sub‐ion‐scale layer containing high amplitude (>50 mV/m) electrostatic waves. In two consecutive separatrix crossings, one exhibits faster electron beams, greater magnetic shear, higher amplitude waves, and more electron heating than the other. The observations suggest that variable reconnection outflow pressure is associated with these changes. Coincident with lower hybrid waves are Buneman and beam‐mode instabilities, likely responsible for parallel heating of electrons. Dissipation (J⋅E) within the mixing layer is found to be negative where wave activity is strongest, indicating a slowing of electrons and growth of electromagnetic fields likely related to local thinning of the separatrix. Calculation of momentum balance via the generalized Ohm's law indicates an overall imbalance of >40 mV/m in the more extreme separatrix crossing, requiring a significant dissipative term or error in the electron inertial term to make up the remainder. Finally, an analysis of quasi‐viscous heating shows that active heating of electrons is more prevalent in the presence of a high speed electron inflow and increased magnetic shear.
Wedge Plasticity and Fully Coupled Simulations of Dynamic Rupture and Tsunami in the Cascadia Subduction Zone
Authors: Wilson Andrew , Ma Shuo 
Published: June 2021

AbstractInelastic wedge deformation likely plays an important role in the generation of tsunami and ocean acoustic waves in accretionary subduction margins. In an elastic dislocation model, whether or not the fault breaks the trench has a significant effect on seafloor deformation and resulting tsunami. However, this boundary condition is less important when significant inelastic deformation in the overriding wedge occurs, because large seafloor uplift can occur with little or no slip at the trench. Here we incorporate wedge plasticity in fully coupled dynamic rupture and tsunami simulations for a buried fault in the Cascadia subduction zone with realistic fault geometry, bathymetry, and velocity structure. A linearized Eulerian approach is verified and used to simulate gravity waves in the ocean. Our coupled models show that the inelastic deformation of wedge sediments can significantly contribute to seafloor uplift, producing tsunami heights at least twice as large as in purely elastic simulations, whilst generating weaker ocean acoustic and seismic waves. Inelastic wedge deformation is therefore an important mechanism to consider in tsunami hazard assessment in the Cascadia subduction zone. These results have important implications for tsunami generation and early warning in accretionary and other sediment‐filled margins worldwide.
Markov Chain‐Based Stochastic Modeling of Deep Signal Fading: Availability Assessment of Dual‐Frequency GNSS‐Based Aviation Under Ionospheric Scintillation
Authors: Sun Andrew K. , Chang Hyeyeon , Pullen Sam , Kil Hyosub , Seo Jiwon , Morton Y. Jade , Lee Jiyun 
Published: June 2021

AbstractDeep signal fading due to ionospheric scintillation severely impacts global navigation satellite system (GNSS)‐based applications. GNSS receivers run the risk of signal loss under deep fading, which directly leads to a significant decrease in navigation availability. The impact of scintillation on GNSS‐based applications can be mitigated via dual‐frequency signals which provide a backup channel. However, the benefit of dual‐frequency diversity highly depends on the correlation of fading processes between signals at different frequencies. This paper proposes a Markov chain‐based model that simulates the actual behavior of correlated fading processes in dual‐frequency channels. A set of recorded scintillation data was used to capture transitions among all fading states based on the fading and recovery of each signal frequency. A statistical study of deep fading characteristics in this data revealed that the Markov chain‐based model accurately generates realistic correlated fading processes. Using the proposed model, aviation availability of localizer performance with vertical guidance down to a 200‐foot decision height (“LPV‐200”) under a strong scintillation scenario is analyzed by considering the effects of signal outages due to deep fading. A parametric analysis of the availability resulting from variations in mean time to loss of lock, mean time to reacquisition, and ionospheric delay uncertainty was conducted to investigate the performance standards on GNSS‐based aviation under scintillation. The analysis results demonstrate a significant benefit of frequency diversity on aviation availability during scintillation. This model will further enable the assessment of GNSS‐based availability for aviation and other applications under a full range of scintillation conditions.
Relevance of the North‐South Electric Field Component in the Propagation of Fast Convective Earthward Flows in the Magnetotail: An Event Study
Authors: Pitkänen T. , Hamrin M. , Chong G. S. , Kullen A. 
Published: June 2021

AbstractFast earthward plasma flows are commonly observed in the magnetotail plasma sheet. These flows are often termed as bursty bulk flows because of their bursty nature, and they are considered to be generated by magnetic reconnection. Close to the neutral sheet (Bx ∼ 0), the fast flows are considered to be associated with an enhanced dawn‐to‐dusk electric field (Ey > 0), which together with the northward magnetic field component (Bz > 0) protrude the plasma earthward via enhanced E × B‐drift. Sometimes, reversals in the dawn‐dusk velocity component perpendicular to the magnetic field (V⊥y) are measured in association with Bx sign changes in the flows. This suggests that the electric field component in the north‐south direction (Ez) can play a role in determining the dawn‐dusk direction of the enhanced drift. We present data measured by the Magnetospheric Multiscale, which demonstrate that Ez can have a dictating role for V⊥y of fast flows. Furthermore, it is shown that the critical contribution of Ez is not limited only to V⊥y, but it can also dominantly determine the enhanced drift of the fast flows in the X direction (V⊥x). The latter can occur also near and at the neutral sheet, which adds an alternative configuration to the conventional picture of Ey and Bz being the main players in driving the earthward fast flows. The domination of Ez in the studied events appears with potential signatures of an influence of a nonzero dawn‐dusk component of the interplanetary magnetic field (IMF By) on the magnetotail.
Interactions between large molecules pose a puzzle for reference quantum mechanical methods
Authors: Al-Hamdani Yasmine S. , Nagy Péter R. , Zen Andrea , Barton Dennis , Kállay Mihály , Brandenburg Jan Gerit , Tkatchenko Alexandre 
Published: June 2021

AbstractQuantum-mechanical methods are used for understanding molecular interactions throughout the natural sciences. Quantum diffusion Monte Carlo (DMC) and coupled cluster with single, double, and perturbative triple excitations [CCSD(T)] are state-of-the-art trusted wavefunction methods that have been shown to yield accurate interaction energies for small organic molecules. These methods provide valuable reference information for widely-used semi-empirical and machine learning potentials, especially where experimental information is scarce. However, agreement for systems beyond small molecules is a crucial remaining milestone for cementing the benchmark accuracy of these methods. We show that CCSD(T) and DMC interaction energies are not consistent for a set of polarizable supramolecules. Whilst there is agreement for some of the complexes, in a few key systems disagreements of up to 8 kcal mol−1 remain. These findings thus indicate that more caution is required when aiming at reproducible non-covalent interactions between extended molecules.
Ocean-bottom and surface seismometers reveal continuous glacial tremor and slip
Authors: Podolskiy Evgeny A. , Murai Yoshio , Kanna Naoya , Sugiyama Shin 
Published: June 2021

AbstractShearing along subduction zones, laboratory experiments on analogue faults, and sliding along glacier beds are all associated with aseismic and co-seismic slip. In this study, an ocean-bottom seismometer is deployed near the terminus of a Greenlandic tidewater glacier, effectively insulating the signal from the extremely noisy surface seismic wavefield. Continuous, tide-modulated tremor related to ice speed is recorded at the bed of the glacier. When noise interference (for example, due to strong winds) is low, the tremor is also confirmed via analysis of seismic waveforms from surface stations. The signal resembles the tectonic tremor commonly observed during slow-earthquake events in subduction zones. We propose that the glacier sliding velocity can be retrieved from the observed seismic noise. Our approach may open new opportunities for monitoring calving-front processes in one of the most difficult-to-access cryospheric environments.
Anisotropic moiré optical transitions in twisted monolayer/bilayer phosphorene heterostructures
Authors: Zhao Shilong , Wang Erqing , Üzer Ebru Alime , Guo Shuaifei , Qi Ruishi , Tan Junyang , Watanabe Kenji , Taniguchi Takashi , Nilges Tom , Gao Peng , Zhang Yuanbo , Cheng Hui-Ming , Liu Bilu , Zou Xiaolong , Wang Feng 
Published: June 2021

AbstractMoiré superlattices of van der Waals heterostructures provide a powerful way to engineer electronic structures of two-dimensional materials. Many novel quantum phenomena have emerged in graphene and transition metal dichalcogenide moiré systems. Twisted phosphorene offers another attractive system to explore moiré physics because phosphorene features an anisotropic rectangular lattice, different from isotropic hexagonal lattices previously reported. Here we report emerging anisotropic moiré optical transitions in twisted monolayer/bilayer phosphorenes. The optical resonances in phosphorene moiré superlattice depend sensitively on twist angle and are completely different from those in the constitute monolayer and bilayer phosphorene even for a twist angle as large as 19°. Our calculations reveal that the Γ-point direct bandgap and the rectangular lattice of phosphorene give rise to the remarkably strong moiré physics in large-twist-angle phosphorene heterostructures. This work highlights fresh opportunities to explore moiré physics in phosphorene and other van der Waals heterostructures with different lattice configurations.
Oral administration of bovine milk-derived extracellular vesicles induces senescence in the primary tumor but accelerates cancer metastasis
Authors: Samuel Monisha , Fonseka Pamali , Sanwlani Rahul , Gangoda Lahiru , Chee Sing Ho , Keerthikumar Shivakumar , Spurling Alex , Chitti Sai V. , Zanker Damien , Ang Ching-Seng , Atukorala Ishara , Kang Taeyoung , Shahi Sanjay , Marzan Akbar L. , Nedeva Christina , Vennin Claire , Lucas Morghan C. , Cheng Lesley , Herrmann David , Pathan Mohashin , Chisanga David , Warren Sean C. , Zhao Kening , Abraham Nidhi , Anand Sushma , Boukouris Stephanie , Adda Christopher G. , Jiang Lanzhou , Shekhar Tanmay M. , Baschuk Nikola , Hawkins Christine J. , Johnston Amelia J. , Orian Jacqueline Monique , Hoogenraad Nicholas J. , Poon Ivan K. , Hill Andrew F. , Jois Markandeya , Timpson Paul , Parker Belinda S. , Mathivanan Suresh 
Published: June 2021

AbstractThe concept that extracellular vesicles (EVs) from the diet can be absorbed by the intestinal tract of the consuming organism, be bioavailable in various organs, and in-turn exert phenotypic changes is highly debatable. Here, we isolate EVs from both raw and commercial bovine milk and characterize them by electron microscopy, nanoparticle tracking analysis, western blotting, quantitative proteomics and small RNA sequencing analysis. Orally administered bovine milk-derived EVs survive the harsh degrading conditions of the gut, in mice, and is subsequently detected in multiple organs. Milk-derived EVs orally administered to mice implanted with colorectal and breast cancer cells reduce the primary tumor burden. Intriguingly, despite the reduction in primary tumor growth, milk-derived EVs accelerate metastasis in breast and pancreatic cancer mouse models. Proteomic and biochemical analysis reveal the induction of senescence and epithelial-to-mesenchymal transition in cancer cells upon treatment with milk-derived EVs. Timing of EV administration is critical as oral administration after resection of the primary tumor reverses the pro-metastatic effects of milk-derived EVs in breast cancer models. Taken together, our study provides context-based and opposing roles of milk-derived EVs as metastasis inducers and suppressors.
A cell-based in vitro assay for testing of immunological integrity of Tetanus toxoid vaccine antigen
Authors: Ticha Olga , Klemm Dido , Moos Lukas , Bekeredjian-Ding Isabelle 
Published: June 2021

AbstractVaccines containing inactivated toxins confer protection by eliciting a neutralizing antibody response against bacterial toxins such as tetanus and diphtheria. At present, release of tetanus toxoid (TT) and diphtheria toxoid (DT)-containing vaccines relies on in vivo experiments showing the protective vaccine response. The aim of this study was to develop a reliable in vitro assay for TT vaccine antigen characterization with the potential of replacing in vivo potency experiments. To this end, we exploited that TT elicits a recall response in vaccinated donors: human peripheral blood mononuclear cells (PBMC) were stimulated with alum-adsorbed TT bulk antigen and low concentrations of TLR9 ligand; induction of TT-specific IgG was quantified via ELISpot after 5 days. Proof-of-concept was obtained using paired samples from donors before and after vaccination; anti-TT IgG was only detected in PBMC collected after booster vaccination; specificity was demonstrated with DT stimulation as control. Notably, when using PBMC from buffy coats, the specific response to TT was reproducible in 30% of cells; responsiveness correlated with higher numbers of switched memory B cells. Consecutive results showed that TT-specific IgG was also detectable when PBMC were stimulated with DTaP final vaccine product. Thus, the assay provides a viable means to test B-cell differentiation and induction of TT-specific IgG secretion using bulk antigen and final vaccine. However, prequalification of PBMC is required for reliable performance. Along with physicochemical and immunochemical methods, the functional assay could represent a complementary tool to replace in vivo potency assays in batch release of TT-containing vaccines.
Assessing inequality, irregularity, and severity regarding road traffic safety during COVID-19
Authors: Lin Lei , Shi Feng , Li Weizi 
Published: June 2021

AbstractCOVID-19 has affected every sector of our society, among which human mobility is taking a dramatic change due to quarantine and social distancing. We investigate the impact of the pandemic and subsequent mobility changes on road traffic safety. Using traffic accident data from the city of Los Angeles and New York City, we find that the impact is not merely a blunt reduction in traffic and accidents; rather, (1) the proportion of accidents unexpectedly increases for “Hispanic” and “Male” groups; (2) the “hot spots” of accidents have shifted in both time and space and are likely moved from higher-income areas (e.g., Hollywood and Lower Manhattan) to lower-income areas (e.g., southern LA and southern Brooklyn); (3) the severity level of accidents decreases with the number of accidents regardless of transportation modes. Understanding those variations of traffic accidents not only sheds a light on the heterogeneous impact of COVID-19 across demographic and geographic factors, but also helps policymakers and planners design more effective safety policies and interventions during critical conditions such as the pandemic.
Flow-induced surface crystallization of granular particles in cylindrical confinement
Authors: Zhang Sheng , Lin Ping , Wang Mengke , Wan Jiang-feng , Peng Yi , Yang Lei , Hou Meiying 
Published: June 2021

AbstractAn interesting phenomenon that a layer of crystallized shell formed at the container wall during an orifice flow in a cylinder is observed experimentally and is investigated in DEM simulation. Different from shear or vibration driven granular crystallization, our simulation shows during the flow the shell layer is formed spontaneously from stagnant zone at the base and grows at a constant rate to the top with no external drive. Roughness of the shell surface is defined as a standard deviation of the surface height and its development is found to disobey existed growth models. The growth rate of the shell is found linearly proportional to the flow rate. This shell is static and served as a rough wall in an orifice flow with frictionless sidewall, which changes the flow profiles and its stress properties, and in turn guarantees a constant flow rate.
Manipulating polymer composition to create low-cost, high-fidelity sensors for indoor CO2 monitoring
Authors: Siefker Zachary A. , Hodul John N. , Zhao Xikang , Bajaj Nikhil , Brayton Kelly M. , Flores-Hansen Carsten , Zhao Wenchao , Chiu George T.-C. , Braun James E. , Rhoads Jeffrey F. , Boudouris Bryan W. 
Published: June 2021

AbstractCarbon dioxide (CO2) has been linked to many deleterious health effects, and it has also been used as a proxy for building occupancy measurements. These applications have created a need for low-cost and low-power CO2 sensors that can be seamlessly incorporated into existing buildings. We report a resonant mass sensor coated with a solution-processable polymer blend of poly(ethylene oxide) (PEO) and poly(ethyleneimine) (PEI) for the detection of CO2 across multiple use conditions. Controlling the polymer blend composition and nanostructure enabled better transport of the analyte gas into the sensing layer, which allowed for significantly enhanced CO2 sensing relative to the state of the art. Moreover, the hydrophilic nature of PEO resulted in water uptake, which provided for higher sensing sensitivity at elevated humidity conditions. Therefore, this key integration of materials and resonant sensor platform could be a potential solution in the future for CO2 monitoring in smart infrastructure.