67,795 research outputs found
A mid-infrared exploration of the dusty environments of active galactic nuclei
We present the first results from a mid-infrared survey of local Active
Galactic Nuclei (AGN) using the CanariCam (CC) instrument on the 10.4m Gran
Telescopio Canarias (GTC). We are obtaining sub-arcsecond angular resolution
(0.3-0.6 arcsec) mid-IR imaging and spectroscopic observations of a sample of
100 local AGN, which are complemented with data taken with T-ReCS, VISIR, and
Michelle. The full sample contains approximately 140 AGN, covers nearly six
orders of magnitude in AGN luminosity, and includes low-luminosity AGN (LLAGN),
Seyfert 1s and 2s, QSO, radio galaxies, and (U)LIRGs. The main goals of this
project are: (1) to test whether the properties of the dusty tori of the AGN
Unified Model depend on the AGN type, (2) to study the nuclear star formation
activity and obscuration of local AGN, and (3) to explore the role of the dusty
torus in LLAGN.Comment: Conference proceedings of IAU Symposium 304: Multiwavelength AGN
surveys and studie
Kinetic-growth self-avoiding walks on small-world networks
Kinetically-grown self-avoiding walks have been studied on Watts-Strogatz
small-world networks, rewired from a two-dimensional square lattice. The
maximum length L of this kind of walks is limited in regular lattices by an
attrition effect, which gives finite values for its mean value . For
random networks, this mean attrition length scales as a power of the
network size, and diverges in the thermodynamic limit (large system size N).
For small-world networks, we find a behavior that interpolates between those
corresponding to regular lattices and randon networks, for rewiring probability
p ranging from 0 to 1. For p < 1, the mean self-intersection and attrition
length of kinetically-grown walks are finite. For p = 1, grows with
system size as N^{1/2}, diverging in the thermodynamic limit. In this limit and
close to p = 1, the mean attrition length diverges as (1-p)^{-4}. Results of
approximate probabilistic calculations agree well with those derived from
numerical simulations.Comment: 10 pages, 7 figure
Analysis for time discrete approximations of blow-up solutions of semilinear parabolic equations
We prove a posteriori error estimates for time discrete approximations, for semilinear parabolic equations with solutions that might blow up in finite time. In particular we consider the backward Euler and the Crank–Nicolson methods. The main tools that are used in the analysis are the reconstruction technique and energy methods combined with appropriate fixed point arguments. The final estimates we derive are conditional and lead to error control near the blow up time
From globalization to deglobalization: Zooming into trade. Bruegel Special Report
After decades of increasing globalization both in trade, capital flows but even people to people movements, it seems the trend has turned
towards deglobalization. This article shows some evidence of the decrease in merchandise, capital and, to a lesser extent people to people
flows. In addition, zooming into trade, the article offers an account of the importance of the strategic competition between the US and
China to foster the deglobalization trend further. This is true for trade but even beyond in the tech and finance space. Finally, the demise
of the WTO could be one of the most relevant turning points towards deglobalization, especially as far as trade is concerned. This should
bring downward pressure to growth globally
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