34 research outputs found
Dynamic scaling in vacancy-mediated disordering
We consider the disordering dynamics of an interacting binary alloy with a
small admixture of vacancies which mediate atom-atom exchanges. Starting from a
perfectly phase-segregated state, the system is rapidly heated to a temperature
in the disordered phase. A suitable disorder parameter, namely, the number of
broken bonds, is monitored as a function of time. Using Monte Carlo simulations
and a coarse-grained field theory, we show that the late stages of this process
exhibit dynamic scaling, characterized by a set of scaling functions and
exponents. We discuss the universality of these exponents and comment on some
subtleties in the early stages of the disordering process.Comment: 15 pages, 6 figure
Effects of Static Magnetic Field on Growth of Leptospire, Leptospira interrogans serovar canicola: Immunoreactivity and Cell Division
The effects of the exposure of the bacterium, Leptospira interrogans serovar
canicola to a constant magnetic field with magnetic flux density from a
permanent ferrite magnet = 140 mT were studied. Changes in Leptospira cells
after their exposure to the field were determined on the basis of changes in
their growth behavior and agglutination immunoreactivity with a homologous
antiserum using darkfield microscopy together with visual imaging. The data
showed that the exposed Leptospira cells have lower densities and lower
agglutination immunoreactivity than the unexposed control group. Interestingly,
some of the exposed Leptospira cells showed abnormal morphologies such as large
lengths. We discussed some of the possible reasons for these observations.Comment: 21 pages, 5 figures, 1 tabl
Binary data corruption due to a Brownian agent
We introduce a model of binary data corruption induced by a Brownian agent
(active random walker) on a d-dimensional lattice. A continuum formulation
allows the exact calculation of several quantities related to the density of
corrupted bits \rho; for example the mean of \rho, and the density-density
correlation function. Excellent agreement is found with the results from
numerical simulations. We also calculate the probability distribution of \rho
in d=1, which is found to be log-normal, indicating that the system is governed
by extreme fluctuations.Comment: 39 pages, 10 figures, RevTe
A mechanism of raft formation on both plasma membrane layers
A double-layered membrane model is proposed to explain raft formation and induction on extracellular (outer) and cytoplasmic (inner) leaflets of plasma membranes in a situation where only the outer layer has a tendency to phase-separate. In the model, lipid exchange with the surrounding medium is allowed on both layers, but lipid exchange between layers is not allowed. Simulations display domain stabilization on both layers. The effect of the lipid recycling frequencies on stationary domain sizes is also investigated. It is found that stationary domain sizes decrease when lipid recycling frequencies are stronger. Linear stability analysis is used to verify the results