14,059 research outputs found
Cellular automaton supercolliders
Gliders in one-dimensional cellular automata are compact groups of
non-quiescent and non-ether patterns (ether represents a periodic background)
translating along automaton lattice. They are cellular-automaton analogous of
localizations or quasi-local collective excitations travelling in a spatially
extended non-linear medium. They can be considered as binary strings or symbols
travelling along a one-dimensional ring, interacting with each other and
changing their states, or symbolic values, as a result of interactions. We
analyse what types of interaction occur between gliders travelling on a
cellular automaton `cyclotron' and build a catalog of the most common
reactions. We demonstrate that collisions between gliders emulate the basic
types of interaction that occur between localizations in non-linear media:
fusion, elastic collision, and soliton-like collision. Computational outcomes
of a swarm of gliders circling on a one-dimensional torus are analysed via
implementation of cyclic tag systems
Mean Field Approach for a Statistical Mechanical Model of Proteins
We study the thermodynamical properties of a topology-based model proposed by
Galzitskaya and Finkelstein for the description of protein folding. We devise
and test three different mean-field approaches for the model, that simplify the
treatment without spoiling the description. The validity of the model and its
mean-field approximations is checked by applying them to the -hairpin
fragment of the immunoglobulin-binding protein (GB1) and making a comparison
with available experimental data and simulation results. Our results indicate
that this model is a rather simple and reasonably good tool for interpreting
folding experimental data, provided the parameters of the model are carefully
chosen. The mean-field approaches substantially recover all the relevant exact
results and represent reliable alternatives to the Monte Carlo simulations.Comment: RevTeX-4, 11 pages, 6 eps-figures, To Appear on J.Chem.Phy
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