22,900 research outputs found
A mechanism for unipolar resistance switching in oxide non-volatile memory devices
Building on a recently introduced model for non-volatile resistive switching,
we propose a mechanism for unipolar resistance switching in
metal-insulator-metal sandwich structures. The commutation from the high to low
resistance state and back can be achieved with successive voltage sweeps of the
same polarity. Electronic correlation effects at the metal-insulator interface
are found to play a key role to produce a resistive commutation effect in
qualitative agreement with recent experimental reports on binary transition
metal oxide based sandwich structures.Comment: 4 pages, 2 figure
La Iglesia Católica, maestra y educadora de los pueblos : discurso leído en la solemne inauguración del curso académico de 1931-1932 en el Seminario Conciliar de Osma
Do galaxies form a spectroscopic sequence?
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2011 RAS © The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.We identify a spectroscopic sequence of galaxies, analogous to the Hubble sequence of morphological types, based on the Automatic Spectroscopic K-means-based (ASK) classification. Considering galaxy spectra as multidimensional vectors, the majority of the spectral classes are distributed along a well-defined curve going from the earliest to the latest types, suggesting that the optical spectra of normal galaxies can be described in terms of a single affine parameter. Optically bright active galaxies, however, appear as an independent, roughly orthogonal branch that intersects the main sequence exactly at the transition between early and late typesThis work has been funded by projects AYA2007-67965-C03-03, AYA 2007-67965-C03-01, AYA2007-67752-C03-01 and CSD 2006-00070 (Spanish Ministry of Science, Technology and Innovation
Differentiation enhances Zika virus infection of neuronal brain cells.
Zika virus (ZIKV) is an emerging, mosquito-borne pathogen associated with a widespread 2015-2016 epidemic in the Western Hemisphere and a proven cause of microcephaly and other fetal brain defects in infants born to infected mothers. ZIKV infections have been also linked to other neurological illnesses in infected adults and children, including Guillain-Barré syndrome (GBS), acute flaccid paralysis (AFP) and meningoencephalitis, but the viral pathophysiology behind those conditions remains poorly understood. Here we investigated ZIKV infectivity in neuroblastoma SH-SY5Y cells, both undifferentiated and following differentiation with retinoic acid. We found that multiple ZIKV strains, representing both the prototype African and contemporary Asian epidemic lineages, were able to replicate in SH-SY5Y cells. Differentiation with resultant expression of mature neuron markers increased infectivity in these cells, and the extent of infectivity correlated with degree of differentiation. New viral particles in infected cells were visualized by electron microscopy and found to be primarily situated inside vesicles; overt damage to the Golgi apparatus was also observed. Enhanced ZIKV infectivity in a neural cell line following differentiation may contribute to viral neuropathogenesis in the developing or mature central nervous system
Don Francisco de Quevedo : drama en cuatro actos
Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-201
Noise Effects on Synchronized Globally Coupled Oscillators
The synchronized phase of globally coupled nonlinear oscillators subject to
noise fluctuations is studied by means of a new analytical approach able to
tackle general couplings, nonlinearities, and noise temporal correlations. Our
results show that the interplay between coupling and noise modifies the
effective frequency of the system in a non trivial way. Whereas for linear
couplings the effect of noise is always to increase the effective frequency,
for nonlinear couplings the noise influence is shown to be positive or negative
depending on the problem parameters. Possible experimental verification of the
results is discussed.Comment: 6 Pages, 4 EPS figures included (RevTeX and epsfig needed). Submitted
to Phys. Re
- …