6,246 research outputs found
A method for classifying mental tasks in the space of EEG transforms
In this article we describe a new method for supervised classification of EEG signals. This method applies to the power spectrum density data and assigns class-dependent information weights to individual pixels, so that the decision is defined by the summary weights of the most informative pixel features. We experimentally analyze several versions of the approach. The informative features appear to be rather similar among different individuals, thus supporting the view that there are subject independent general brain patterns for the same mental task
Identification of a high-velocity compact nebular filament 2.2 arcsec south of the Galactic Centre
The central parsec of the Milky Way is a very special region of our Galaxy;
it contains the supermassive black hole associated with Sgr A* as well as a
significant number of early-type stars and a complex structure of streamers of
neutral and ionized gas, within two parsecs from the centre, representing a
unique laboratory. We report the identification of a high velocity compact
nebular filament 2.2 arcsec south of Sgr A*. The structure extends over ~1
arcsec and presents a strong velocity gradient of ~200 km s^{-1} arcsec^{-1}.
The peak of maximum emission, seen in [Fe III] and He I lines, is located at
d{\alpha} = +0.20 +/- 0.06 arcsec and d{\delta} = -2.20 +/- 0.06 arcsec with
respect to Sgr A*. This position is near the star IRS 33N. The velocity at the
emission peak is Vr = -267 km s^{-1}. The filament has a position angle of PA =
115{\degr} +/- 10{\degr}, similar to that of the Bar and of the Eastern Arm at
that position. The peak position is located 0.7 arcsec north of the binary
X-ray and radio transient CXOGX J174540.0-290031, a low-mass X-ray binary with
an orbital period of 7.9 hr. The [Fe III] line emission is strong in the
filament and its vicinity. These lines are probably produced by shock heating
but we cannot exclude some X-ray photoionization from the low-mass X-ray
binary. Although we cannot rule out the idea of a compact nebular jet, we
interpret this filament as a possible shock between the Northern and the
Eastern Arm or between the Northern Arm and the mini-spiral "Bar".Comment: 7 pages, 4 figures, published online in MNRA
Hamiltonian formulation of nonAbelian noncommutative gauge theories
We implement the Hamiltonian treatment of a nonAbelian noncommutative gauge
theory, considering with some detail the algebraic structure of the
noncommutative symmetry group. The first class constraints and Hamiltonian are
obtained and their algebra derived, as well as the form of the gauge invariance
they impose on the first order action.Comment: enlarged version, 7 pages, RevTe
Transcriptomic effects of the non-steroidal anti-inflammatory drug Ibuprofen in the marine bivalve Mytilus galloprovincialis Lam
The transcriptomic effects of Ibuprofen (IBU) in the digestive gland tissue of Mytilus galloprovincialis Lam. specimens exposed at low environmental concentrations (250 ng L-1) are presented. Using a 1.7 K feature cDNA microarray along with linear models and empirical Bayes statistical methods 225 differentially expressed genes were identified in mussels treated with IBU across a 15-day period. Transcriptional dynamics were typical of an adaptive response with a peak of gene expression change at day 7 (177 features, representing about 11% of sequences available for analysis) and an almost full recovery at the end of the exposure period. Functional genomics by means of Gene Ontology term analysis unraveled typical mussel stress responses i.e. aminoglycan (chitin) metabolic processes but also more specific effects such as the regulation of NF-kappa B transcription factor activity. (C) 2016 Elsevier Ltd. All rights reserved
Thermodynamics of quantum crystalline membranes
We investigate the thermodynamic properties and the lattice stability of
two-dimensional crystalline membranes, such as graphene and related compounds,
in the low temperature quantum regime . A key role is played by
the anharmonic coupling between in-plane and out-of plane lattice modes that,
in the quantum limit, has very different consequences than in the classical
regime. The role of retardation, namely of the frequency dependence, in the
effective anharmonic interactions turns out to be crucial in the quantum
regime. We identify a crossover temperature, , between classical and
quantum regimes, which is K for graphene. Below , the
heat capacity and thermal expansion coefficient decrease as power laws with
decreasing temperature, tending to zero for as required by the
third law of thermodynamics.Comment: 13 pages, 1 figur
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