3,642 research outputs found
A New Electric Field in Asymmetric Magnetic Reconnection
We present a theory and numerical evidence for the existence of a previously
unexplored in-plane electric field in collisionless asymmetric magnetic
reconnection. This electric field, dubbed the "Larmor electric field," is
associated with finite Larmor radius effects and is distinct from the known
Hall electric field. Potentially, it could be an important indicator for the
upcoming Magnetospheric Multiscale (MMS) mission to locate reconnection sites
as we expect it to appear on the magnetospheric side, pointing Earthward, at
the dayside magnetopause reconnection site.Comment: 5 pages, 3 figures, to be published in Physical Review Letter
Unsupervised Bilingual POS Tagging with Markov Random Fields
In this paper, we give a treatment to the problem of bilingual part-of-speech induction with parallel data. We demonstrate that naïve optimization of log-likelihood with joint MRFs suffers from a severe problem of local maxima, and suggest an alternative – using contrastive estimation for estimation of the parameters. Our experiments show that estimating the parameters this way, using overlapping features with joint MRFs performs better than previous work on the 1984 dataset.
Beaming Binaries - a New Observational Category of Photometric Binary Stars
The new photometric space-borne survey missions CoRoT and Kepler will be able
to detect minute flux variations in binary stars due to relativistic beaming
caused by the line-of-sight motion of their components. In all but very short
period binaries (P>10d), these variations will dominate over the ellipsoidal
and reflection periodic variability. Thus, CoRoT and Kepler will discover a new
observational class: photometric beaming binary stars. We examine this new
category and the information that the photometric variations can provide. The
variations that result from the observatory heliocentric velocity can be used
to extract some spectral information even for single stars.Comment: 15 pages, 4 figures, accpeted for publication in The Astrophysical
Journa
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