2,896 research outputs found
Aubry sets for weakly coupled systems of Hamilton--Jacobi equations
We introduce a notion of Aubry set for weakly coupled systems of
Hamilton--Jacobi equations on the torus and characterize it as the region where
the obstruction to the existence of globally strict critical subsolutions
concentrates. As in the case of a single equation, we prove the existence of
critical subsolutions which are strict and smooth outside the Aubry set. This
allows us to derive in a simple way a comparison result among critical sub and
supersolutions with respect to their boundary data on the Aubry set, showing in
particular that the latter is a uniqueness set for the critical system. We also
highlight some rigidity phenomena taking place on the Aubry set.Comment: 35 pages v.2 the introduction has been rewritten and shortened. Some
proofs simplified. Corrections and references added. Corollary 5.3 added
stating antisymmetry of the Ma\~n\'e matrix on points of the Aubry set.
Section 6 contains a new example
Spontaneous hot-electron light emission from electron-fed optical antennas
Nanoscale electronics and photonics are among the most promising research
areas providing functional nano-components for data transfer and signal
processing. By adopting metal-based optical antennas as a disruptive
technological vehicle, we demonstrate that these two device-generating
technologies can be interfaced to create an electronically-driven self-emitting
unit. This nanoscale plasmonic transmitter operates by injecting electrons in a
contacted tunneling antenna feedgap. Under certain operating conditions, we
show that the antenna enters a highly nonlinear regime in which the energy of
the emitted photons exceeds the quantum limit imposed by the applied bias. We
propose a model based upon the spontaneous emission of hot electrons that
correctly reproduces the experimental findings. The electron-fed optical
antennas described here are critical devices for interfacing electrons and
photons, enabling thus the development of optical transceivers for on-chip
wireless broadcasting of information at the nanoscale
Large-Scale Molecular Dynamics Elucidates the Mechanics of Reinforcement in Graphene-Based Composites
Using very large-scale classical molecular dynamics we examine the mechanics of nano-reinforcement of graphene-based nanocomposites. Our simulations show that significant quantities of large, defect-free and predominantly flat graphene flakes are required for successful enhancement of materials properties in excellent agreement with experimental and proposed continuum shear-lag theories. The critical length for enhancement is approximately 500nm and 300nm for graphene and GO respectively. The reduction of Young's modulus in GO results in a much smaller enhancement of the composite's Young's modulus. The simulations reveal that the flakes should be aligned and planar for optimal reinforcement. Undulations substantially degrade the enhancement of materials properties
Live Blog Corpus for Summarization
Live blogs are an increasingly popular news format to cover breaking news and
live events in online journalism. Online news websites around the world are
using this medium to give their readers a minute by minute update on an event.
Good summaries enhance the value of the live blogs for a reader but are often
not available. In this paper, we study a way of collecting corpora for
automatic live blog summarization. In an empirical evaluation using well-known
state-of-the-art summarization systems, we show that live blogs corpus poses
new challenges in the field of summarization. We make our tools publicly
available to reconstruct the corpus to encourage the research community and
replicate our results.Comment: To appear in the Proceedings of LREC 201
Swin2SR: SwinV2 Transformer for Compressed Image Super-Resolution and Restoration
Compression plays an important role on the efficient transmission and storage
of images and videos through band-limited systems such as streaming services,
virtual reality or videogames. However, compression unavoidably leads to
artifacts and the loss of the original information, which may severely degrade
the visual quality. For these reasons, quality enhancement of compressed images
has become a popular research topic. While most state-of-the-art image
restoration methods are based on convolutional neural networks, other
transformers-based methods such as SwinIR, show impressive performance on these
tasks.
In this paper, we explore the novel Swin Transformer V2, to improve SwinIR
for image super-resolution, and in particular, the compressed input scenario.
Using this method we can tackle the major issues in training transformer vision
models, such as training instability, resolution gaps between pre-training and
fine-tuning, and hunger on data. We conduct experiments on three representative
tasks: JPEG compression artifacts removal, image super-resolution (classical
and lightweight), and compressed image super-resolution. Experimental results
demonstrate that our method, Swin2SR, can improve the training convergence and
performance of SwinIR, and is a top-5 solution at the "AIM 2022 Challenge on
Super-Resolution of Compressed Image and Video".Comment: European Conference on Computer Vision (ECCV 2022) Workshop
Second-harmonic-generation of [(Se,Te)Cl] [GaCl] with aligned ionic tetrahedra
[SeCl][GaCl] (1) and [TeCl][GaCl] (2) are prepared via Lewis-acid–base reaction of SeCl or TeCl with GaCl at 50 °C (1) and 140 °C (2) in quantitative yield. The ionic compounds contain pseudo-tetrahedral [SeCl]/[TeCl] cations with a prominent stereochemically active electron lone pair at Se(IV)/Te(IV) as well as tetrahedral [GaCl] anions. Both compounds crystallize in the polar chiral space group P1 with an unidirectional alignment of all tetrahedral building units. They can be considered as the first examples of a much larger group of ionic compounds [MX][M′X] (M, M′: metal or main-group element, X: halogen) showing nonlinear optical effects. Material characterization is performed by X-ray structure analysis based on single crystals and powder samples, thermogravimetry, optical spectroscopy, infrared and Raman spectroscopy. Second harmonic generation (SHG) is observed with intensities about 3-times stronger than for potassium dihydrogen phosphate (KDP) in the visible spectral regime with narrow-band-gap materials (2.8, 3.2 eV). Density functional theory calculations are employed to complement the experimental findings, interpret the Raman spectra, visualize the stereochemically active lone electron pair, and compute the SHG tensor
Diagnostic accuracy of office blood pressure compared to home blood pressure in patients with mild cognitive impairment and dementia
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Proteomic and functional analyses of the virion transmembrane proteome of cyprinid herpesvirus 3
Virion transmembrane proteins (VTPs) mediate key functions in the herpesvirus infectious cycle. Cyprinid herpesvirus 3 (CyHV-3) is the archetype of fish alloherpesviruses. The present study was devoted to CyHV-3 VTPs. Using mass spectrometry approaches, we identified 16 VTPs of the CyHV-3 FL strain. Mutagenesis experiments demonstrated that eight of these proteins are essential for viral growth in vitro (ORF32, ORF59, ORF81, ORF83, ORF99, ORF106, ORF115, and ORF131), and eight are non-essential (ORF25, ORF64, ORF65, ORF108, ORF132, ORF136, ORF148, and ORF149). Among the non-essential proteins, deletion of ORF25, ORF132, ORF136, ORF148, or ORF149 affects viral replication in vitro, and deletion of ORF25, ORF64, ORF108, ORF132, or ORF149 impacts plaque size. Lack of ORF148 or ORF25 causes attenuation in vivo to a minor or major extent, respectively. The safety and efficacy of a virus lacking ORF25 were compared to those of a previously described vaccine candidate deleted for ORF56 and ORF57 (Δ56-57). Using quantitative PCR, we demonstrated that the ORF25 deleted virus infects fish through skin infection and then spreads to internal organs as reported previously for the wild-type parental virus and the Δ56-57 virus. However, compared to the parental wild-type virus, the replication of the ORF25 deleted virus was reduced in intensity and duration to levels similar to those observed for the Δ56-57 virus. Vaccination of fish with a virus lacking ORF25 was safe but had low efficacy at the doses tested. This characterization of the virion transmembrane proteome of CyHV-3 provides a firm basis for further research on alloherpesvirus VTPs.
IMPORTANCE Virion transmembrane proteins play key roles in the biology of herpesviruses. Cyprinid herpesvirus 3 (CyHV-3) is the archetype of fish alloherpesviruses and the causative agent of major economic losses in common and koi carp worldwide. In this study of the virion transmembrane proteome of CyHV-3, the major findings were: (i) the FL strain encodes 16 virion transmembrane proteins; (ii) eight of these proteins are essential for viral growth in vitro; (iii) seven of the non-essential proteins affect viral growth in vitro, and two affect virulence in vivo; and (iv) a mutant lacking ORF25 is highly attenuated but induces moderate immune protection. This study represents a major breakthrough in understanding the biology of CyHV-3 and will contribute to the development of prophylactic methods. It also provides a firm basis for the further research on alloherpesvirus virion transmembrane proteins
Ultra-light Axions: Degeneracies with Massive Neutrinos and Forecasts for Future Cosmological Observations
A generic prediction of string theory is the existence of many axion fields.
It has recently been argued that many of these fields should be light and, like
the well known QCD axion, lead to observable cosmological consequences. In this
paper we study in detail the effect of the so-called string axiverse on large
scale structure, focusing on the morphology and evolution of density
perturbations, anisotropies in the cosmic microwave background and weak
gravitational lensing of distant galaxies. We quantify specific effects that
will arise from the presence of the axionic fields and highlight possible
degeneracies that may arise in the presence of massive neutrinos. We take
particular care understanding the different physical effects and scales that
come into play. We then forecast how the string axiverse may be constrained and
show that with a combination of different observations, it should be possible
to detect a fraction of ultralight axions to dark matter of a few percent.Comment: 24 pages, 16 figures, this version: corrected typos, some comments
added, matches published versio
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