7,567 research outputs found
Glassy Behavior of Electrons as a Precursor to the Localization Transition
A theoretical model is presented, describing the glassy freezing of electrons
in the vicinity of disorder driven metal-insulator transitions. Our results
indicate that the onset of glassy dynamics should emerge before the
localization transition is reached, thus predicting the existence of an
intermediate metallic glass phase between the normal metal and the insulator.Comment: Six pages, one EPS figure; proceedings of EP2DS-1
Isolation of Ribosomal Particles from the Unicellular Cyanobacterium Synechocystis sp. PCC 6803
Isolation of ribosomal particles is an essential step in the study of ribosomal components as
well as in the analysis of trans-acting factors that interact with the ribosome to regulate protein synthesis
and modulate the expression profile of the cell in response to different environmental conditions. In this
protocol, we describe a procedure for the isolation of 70S ribosomes from the unicellular cyanobacterium
Synechocystis sp. PCC 6803 (hereafter Synechocystis). We have successfully used this protocol in our
study of the cyanobacterial ribosomal-associated protein LrtA, which is a homologue of bacterial HPF
(hibernation promoting factor) (Galmozzi et al., 2016).España, Junta de Andalucía grant P07-CVI-02792 and group BIO-284España, MINECO y Fondo Social Europeo grant BFU2013-41712-
Square-free class sizes in products of groups
We obtain some structural properties of a factorised group , given
that the conjugacy class sizes of certain elements in are not
divisible by , for some prime . The case when is a mutually
permutable product is especially considered
Quantum electrodynamic calculation of the hyperfine structure of 3He
The combined fine and hyperfine structure of the states in He is
calculated within the framework of nonrelativistic quantum electrodynamics. The
calculation accounts for the effects of order and increases the
accuracy of theoretical predictions by an order of magnitude. The results
obtained are in good agreement with recent spectroscopic measurements in
He.Comment: 13 pages, spelling and grammar correcte
Spectral distortion of cosmic background radiation by scattering on hot electrons. Exact calculations
The spectral distortion of the cosmic background radiation produced by the
inverse Compton scattering on hot electrons in clusters of galaxies (thermal
Sunyaev-Zeldovich effect) is calculated for arbitrary optical depth and
electron temperature. The distortion is found by a numerical solution of the
exact Boltzmann equation for the photon distribution function. In the limit of
small optical depth and low electron temperature our results confirm the
previous analyses. In the opposite limits, our method is the only one that
permits to make accurate calculations.Comment: 18 pages, 7 figures, to be published in Ap
A model of large-scale proteome evolution
The next step in the understanding of the genome organization, after the
determination of complete sequences, involves proteomics. The proteome includes
the whole set of protein-protein interactions, and two recent independent
studies have shown that its topology displays a number of surprising features
shared by other complex networks, both natural and artificial. In order to
understand the origins of this topology and its evolutionary implications, we
present a simple model of proteome evolution that is able to reproduce many of
the observed statistical regularities reported from the analysis of the yeast
proteome. Our results suggest that the observed patterns can be explained by a
process of gene duplication and diversification that would evolve proteome
networks under a selection pressure, favoring robustness against failure of its
individual components
First measurement of cluster temperature using the thermal Sunyaev-Zeldovich effect
We discuss a new method of finding the cluster temperatures which is
independent of distance and therefore very useful for distant clusters. The hot
gas of electrons in clusters of galaxies scatters and distorts the cosmic
microwave background radiation in a well determined way. This
Sunyaev-Zel'dovich (SZ) effect is a useful tool for extracting information
about clusters such as their peculiar radial velocity and optical depth. Here
we show how the temperature of the cluster can be inferred from the SZ effect,
in principle without use of X-ray data. We use recent millimetre observation of
Abell 2163 to determine for the first time a cluster temperature using SZ
observations only. The result T_e = 26^+34_-19 keV at 68% confidence level (at
95% c.l. we find T>1.5 keV) is in reasonable agreement with the X-ray results,
T_e =12.4^+2.8_-1.9 keV.Comment: 7 pages, 2 figure
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