1,307 research outputs found
All-electrical control of single ion spins in a semiconductor
We propose a method for all-electrical initialization, control and readout of
the spin of single ions substituted into a semiconductor. Mn ions in GaAs form
a natural example. In the ion's ground state the Mn core spin magnetic moment
locks antiparallel to the spin and orbital magnetic moment of a bound valence
hole from the GaAs host. Direct electrical manipulation of the ion spin is
possible because electric fields manipulate the orbital wave function of the
hole, and through the spin-orbit coupling the spin is reoriented as well.
Coupling two or more ion spins can be achieved using electrical gates to
control the size of the valence hole wave function near the semiconductor
surface. This proposal for coherent manipulation of individual ionic spins and
controlled coupling of ionic spins via electrical gates alone may find
applications in extremely high density information storage and in scalable
coherent or quantum information processing.Comment: 5 pages, 3 figure
COMPASS server for remote homology inference
COMPASS is a method for homology detection and local alignment construction based on the comparison of multiple sequence alignments (MSAs). The method derives numerical profiles from given MSAs, constructs local profile-profile alignments and analytically estimates E-values for the detected similarities. Until now, COMPASS was only available for download and local installation. Here, we present a new web server featuring the latest version of COMPASS, which provides (i) increased sensitivity and selectivity of homology detection; (ii) longer, more complete alignments; and (iii) faster computational speed. After submission of the query MSA or single sequence, the server performs searches versus a user-specified database. The server includes detailed and intuitive control of the search parameters. A flexible output format, structured similarly to BLAST and PSI-BLAST, provides an easy way to read and analyze the detected profile similarities. Brief help sections are available for all input parameters and output options, along with detailed documentation. To illustrate the value of this tool for protein structure-functional prediction, we present two examples of detecting distant homologs for uncharacterized protein families. Available at http://prodata.swmed.edu/compas
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
Condensation in a zero range process on weighted scale-free networks
We study the condensation phenomenon in a zero range process on weighted
scale-free networks in order to show how the weighted transport influences the
particle condensation. Instead of the approach of grand canonical ensemble
which is generally used in a zero range process, we introduce an alternate
approach of the mean field equations to study the dynamics of particle
transport. We find that the condensation on scale-free network is easier to
occur in the case of weighted transport than in the case of weight-free. In the
weighted transport, especially, a dynamical condensation is even possible for
the case of no interaction among particles, which is impossible in the case of
weight-free.Comment: 6 pages, 4 figure
Effect of Rainfall for the Dynamical Transmission Model of the Dengue Disease in Thailand
The SEIR (Susceptible-Exposed-Infected-Recovered) model is used to describe the transmission of dengue virus. The main contribution is determining the role of the rainfall in Thailand in the model. The transmission of dengue disease is assumed to depend on the nature of the rainfall in Thailand. We analyze the dynamic transmission of dengue disease. The stability of the solution of the model is analyzed. It is investigated by using the Routh-Hurwitz criteria. We find two equilibrium states: a disease-free state and an endemic equilibrium state. The basic reproductive number (R0) is obtained, which indicates the stability of each equilibrium state. Numerical results taking into account the rainfall are obtained and they are seen to correspond to the analytical results
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