高能暂现源 · 每日文献综述

Rapid and accurate damage assessment plays a pivotal role in mitigating the dire consequences of natural or man-made disasters. Foremost, one of the main reasons for swift damage assessment and disaster response is the potential to save lives. In this study, we exploit the advantage of synthetic aperture radar (SAR) imagery to achieve a quick response over southern Turkey and northern Syria, which experienced two large earthquakes (M 7.8 and M 7.5) on 6th February 2023. We used SAR images supplied from the Sentinel-1 mission to create initial damage maps using interferometric (e.g., coherence) and intensity (e.g., backscattering coefficient) information. The created initial maps together with other influential factors, such as Vs30 (speed of shear wave velocity from the surface to a depth of 30 m), geological and PGA (peak ground acceleration) maps are used to build a new CNN (convolutional neural network) model. The proposed CNN model achieves an overall accuracy of 86% and a kappa coefficient of 0.70 following iterative training and validation. The produced results cover approximately 90,000 km<SUP>2</SUP> and can be used for enhanced search-and-rescue operations.

Some authors have argued that spacetime in general relativity should be given a radically different interpretation from the ones given to spacetime in other theories in virtue of it being a gauge theory. In this article I review this sort of argument and argue against this view. That is, I argue that spacetime in general relativity can be understood analogously to spacetime in other models and that the argument from the diffeomorphism invariance of the theory misapplies the concepts of gauge theory to a context in which they are of limited application.

The study of solar-like oscillating red giants in eclipsing binaries (EBs) provides a unique opportunity to advance stellar astrophysics by combining dynamical mass and radius measurements with asteroseismic constraints. EBs provide precise fundamental parameters (e.g. mass, radius, and luminosity) independent of distance, while solar-like oscillations probe stellar interiors and enable tests of asteroseismic scaling relations used to determine stellar masses and radii. {We apply two different methods to estimate the initial chemical composition of the systems. In Method I, the initial helium abundance ($Y_0$) is treated as the free parameter, whereas in Method II the free parameter is the initial metallicity ($Z_0$), assuming a relation between $Y_0$ and $Z_0$. We construct interior models individually for the components of 11 EBs and obtain coeval solutions for eight systems.} The ages and chemical compositions derived from the two methods are generally consistent with each other. Our results provide important clues about the chemical evolution of a part of the Galactic disk. Moreover, using the parameters obtained for two oscillating stars, Tek Ayak (KIC 8410637) and KIC 9970396, instead of solar reference values in the scaling relations yields masses and radii that are in much better agreement with the dynamical solutions without requiring additional corrections.