32 research outputs found
Symmetry effects and equivalences in lattice models of hydrophobic interaction
We establish the equivalence of a recently introduced discrete model of the
hydrophobic interaction, as well as its extension to continuous state
variables, with the Ising model in a magnetic field with temperature-dependent
strength. In order to capture the effect of symmetries of the solvent particles
we introduce a generalized multi-state model. We solve this model - which is
not of the Ising type - exactly in one dimension. Our findings suggest that a
small increase in symmetry decreases the amplitude of the solvent-mediated part
of the potential of mean force between solute particles and enhances the
solubility in a very simple fashion. High symmetry decreases also the range of
the attractive potential. This weakening of the hydrophobic effect observed in
the model is in agreement with the notion that the effect is entropic in
origin.Comment: 19 pages, 2 figure
Susceptibility amplitude ratios in the two-dimensional Potts model and percolation
The high-temperature susceptibility of the -state Potts model behaves as
as , while for one may define
both longitudinal and transverse susceptibilities, with the same power law but
different amplitudes and . We extend a previous analytic
calculation of the universal ratio in two dimensions to the
low-temperature ratio , and test both predictions with Monte
Carlo simulations for and 4. The data for are inconclusive owing to
large corrections to scaling, while for they appear consistent with the
prediction for , but not with that for . A
simple extrapolation of our analytic results to indicates a similar
discrepancy with the corresponding measured quantities in percolation. We point
out that stronger assumptions were made in the derivation of the ratio
, and our work suggests that these may be unjustified.Comment: 17 pages, late
An assessment of artificial radionuclide transfer from Sellafield to South West Scotland
SIGLEAvailable from British Library Document Supply Centre- DSC:3614.604(DOE/RW--89.127) / BLDSC - British Library Document Supply CentreGBUnited Kingdo