814 research outputs found
Transition from single-file to two-dimensional diffusion of interacting particles in a quasi-one-dimensional channel
Diffusive properties of a monodisperse system of interacting particles
confined to a \textit{quasi}-one-dimensional (Q1D) channel are studied using
molecular dynamics (MD) simulations. We calculate numerically the mean-squared
displacement (MSD) and investigate the influence of the width of the channel
(or the strength of the confinement potential) on diffusion in finite-size
channels of different shapes (i.e., straight and circular). The transition from
single-file diffusion (SFD) to the two-dimensional diffusion regime is
investigated. This transition (regarding the calculation of the scaling
exponent () of the MSD ) as a
function of the width of the channel, is shown to change depending on the
channel's confinement profile. In particular the transition can be either
smooth (i.e., for a parabolic confinement potential) or rather sharp/stepwise
(i.e., for a hard-wall potential), as distinct from infinite channels where
this transition is abrupt. This result can be explained by qualitatively
different distributions of the particle density for the different confinement
potentials.Comment: 13 pages, 11 figure
Implications of Form Invariance to the Structure of Nonextensive Entropies
The form invariance of the statement of the maximum entropy principle and the
metric structure in quantum density matrix theory, when generalized to
nonextensive situations, is shown here to determine the structure of the
nonextensive entropies. This limits the range of the nonextensivity parameter
to so as to preserve the concavity of the entropies. The Tsallis entropy is
thereby found to be appropriately renormalized.Comment: 8 page
Aplastic anemia, clinical implications and DNA damage in workers with occupational exposure to aromatic hydrocarbons in Rio de Janeiro
The aim of this study was to evaluate the clinical complaints and the genotoxic effects in GWS. Materials and methods: Overall, 88 workers were recruited versus 127 control
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