Search results for "SNR"
showing 10 items of 45 documents
Spatial distribution of X-ray emitting ejecta in Tychos SNR: indications of shocked Titanium
2015
Young supernova remnants show a characteristic ejecta-dominated X-ray emission that allows us to probe the products of the explosive nucleosynthesis processes and to ascertain important information about the physics of the supernova explosions. Hard X-ray observations have recently revealed the radioactive decay lines of 44Ti at ~67.9 keV and ~78.4 keV in the Tycho's SNR. We here analyze the set of XMM-Newton archive observations of the Tycho's SNR. We produce equivalent width maps of the Fe K and Ca XIX emission lines and find indications for a stratification of the abundances of these elements and significant anisotropies. We then perform a spatially resolved spectral analysis by identify…
OLF : RGB-D Adaptive Late Fusion for Robust 6D Pose Estimation
2023
RGB-D 6D pose estimation has recently gained significant research attention due to the complementary information provided by depth data. However, in real-world scenarios, especially in industrial applications, the depth and color images are often more noisy. Existing methods typically employ fusion designs that equally average RGB and depth features, which may not be optimal. In this paper, we propose a novel fusion design that adaptively merges RGB-D cues. Our approach involves assigning two learnable weight α 1 and α 2 to adjust the RGB and depth contributions with respect to the network depth. This enables us to improve the robustness against low-quality depth input in a simple yet effec…
Transport of mRNA from Nucleus to Cytoplasm
1987
Publisher Summary Transport of mRNP (messenger ribonucleoprotein) from nucleus to cytoplasm plays an important role in gene expression in eukaryotic cells. This chapter focuses on energy-(ATP)-dependent mRNP transport. Nucleocytoplasmic transport of ribosomal RNA can also be induced by ATP, but also occurs by varying [Ca 2+ ]:[Mg 2+ ]. Release of ribosomal RNPs seems to be accompanied by an expansion of the nucleus. Nucleocytoplasmic transport of mRNA seems to be also distinct from the export of tRNA or the exchange of snRNPs and proteins across the nuclear envelope. Nucleocytoplasmic transport of tRNA seems to involve a facilitated diffusion mechanism, showing saturability and sequence spe…
Signal-to-noise ratio in reproducing kernel Hilbert spaces
2018
This paper introduces the kernel signal-to-noise ratio (kSNR) for different machine learning and signal processing applications}. The kSNR seeks to maximize the signal variance while minimizing the estimated noise variance explicitly in a reproducing kernel Hilbert space (rkHs). The kSNR gives rise to considering complex signal-to-noise relations beyond additive noise models, and can be seen as a useful signal-to-noise regularizer for feature extraction and dimensionality reduction. We show that the kSNR generalizes kernel PCA (and other spectral dimensionality reduction methods), least squares SVM, and kernel ridge regression to deal with cases where signal and noise cannot be assumed inde…
Signal to Noise Ratio of Silicon Photomultipliers measured in the Continuous Wave Regime
2014
We performed a Signal to Noise Ratio characterization, in the continuous wave regime, at different bias voltages, frequencies and temperatures, on a novel class of silicon photomultipliers fabricated in planar technology on silicon p-type substrate. Signal to Noise Ratio has been measured as the ratio of the photogenerated current, filtered and averaged by a lock-in amplifier, and the Root Mean Square deviation of the overall current flowing to the device. The measured noise takes into account the shot noise, resulting from the photocurrent and the dark current. We have also performed a comparison between our SiPMs and a photomultiplier tube in terms of Signal to Noise Ratio, as a function …
Silicon Photomultipliers Signal-to-Noise Ratio in the Continuous Wave Regime
2014
Abstract— We report on Signal-to-Noise Ratio measurements carried out, in the continuous wave regime, at different bias voltages, frequencies and temperatures, on a class of silicon photomultipliers fabricated in planar technology on silicon p- type substrate. Signal-to-Noise Ratio has been measured as the ratio of the photogenerated current, filtered and averaged by a lock-in amplifier, and the Root Mean Square deviation of the same current. The measured noise takes into account the shot noise, resulting from the photocurrent and the dark current. We have also performed a comparison between our SiPMs and a photomultiplier tube in terms of Signal-to-Noise Ratio, as a function of the tempe…
The X-ray emission of the supernova remnant W49B observed withXMM-Newton
2006
In the framework of the study of supernova remnants and their complex interaction with the interstellar medium, we report on an XMM-Newton EPIC observation of the Galactic supernova remnant W49B. We investigate the spatial distribution of the chemical and physical properties of the plasma, so as to get important constraints on the physical scenario, on the dynamics of the supernova explosion, and on the interaction of the supernova remnant with the ambient interstellar clouds. We present line images, equivalent width maps, and a spatially resolved spectral analysis of a set of homogeneous regions. The X-ray spectrum of W49B is characterized by strong K emission lines from Si, S, Ar, Ca and …
Shock-cloud interaction in the Vela SNR II. Hydrodynamic model
2006
In the framework of the study of the X-ray and optical emission in supernova remnants we focus on an isolated X-ray knot in the northern rim of the Vela SNR (Vela FilD), whose X-ray emission has been studied and discussed in Paper I. We aim at understanding the physical origin of the X-ray and optical emission in FilD, at understanding the role of the different physical processes at work, and at obtaining a key for the interpretation of future X-ray observations of SNRs. To this end we have pursued an accurate ``forward'' modeling of the interaction of the Vela SNR shock with an ISM cloud. We perform hydrodynamic simulations and we directly compare the observables synthesized from the simul…
Multi-phase interstellar clouds in the Vela SNR resolved with XMM-Newton
2005
XMM-Newton spatial/spectral resolution and high effective area allow to deepen our knowledge about the shocks in Supernova Remnants and their interaction with the interstellar medium. We present the analysis of an EPIC observation of the northern rim of the Vela SNR and we compare the X-ray and optical morphology of the emission. We derive a description of the internal structure of the shocked interstellar clouds, arguing that the transmitted shock model is compatible with our data. We also suggest that thermal conduction between clouds and inter-cloud medium is very efficient and produces the evaporation of the clouds in the interstellar medium. � 2005 COSPAR. Published by Elsevier Ltd. Al…
Shock-cloud interaction in the Vela SNR observed with XMM-Newton
2005
We analyzed an XMM-Newton EPIC observation of a bright knot, named FilD, in the northern rim of the Vela SNR, where the shock has encountered a cloud. The good combination of sensitivity, spectral, and spatial resolution allowed us to describe the internal structure of the observed ISM clouds and to obtain estimates of their temperature, density, O, Ne, and Fe abundances, and of their extension along the line of sight. We also examined the interaction of the shock with the FilD knot and estimated that the time elapsed from the shock impact is about one cloud crushing time. Our analysis allowed us to conclude that the observed X-ray emission is best explained by the propagation of transmitte…