Biomedical subjects

R Monasson

Publications and source records attributed to R Monasson.

9 recordsLinked to original sources

PubMed2003

Rigorous decimation-based construction of ground pure states for spin-glass models on random lattices.

A constructive scheme for determining pure states at very low temperature in the 3-spins glass model on a random lattice is provided, in full agreement with Parisi's one step replica symmetry breaking (RSB) scheme. Proof is based on the analysis of a partial decimation procedure and of the statistical properties of its output, i.e., a reduced Hamiltonian acting on a subset of the initial spins. The number of ground states (GS) in each state, the number of states, and the distances between GS are calculated and correspond to RSB predictions.

Journal Article↗

PubMed2001

Force and kinetic barriers to unzipping of the DNA double helix.

A theory of the unzipping of double-stranded DNA is presented and is compared to recent micromanipulation experiments. It is shown that the interactions that stabilize the double helix and the elastic rigidity of single strands simply determine the sequence-dependent approximately 12-pN force threshold for DNA strand separation. Using a semimicroscopic model of the binding between nucleotide strands, we show that the greater rigidity of the strands when formed into double-stranded DNA, relative to that of isolated strands, gives rise to a potential barrier to unzipping. The effects of this barrier are derived analytically. The force to keep the extremities of the molecule at a fixed distance, the kinetic rates for strand unpairing at fixed applied force, and the rupture force as a function of loading rate are calculated. The dependence of the kinetics and of the rupture force on molecule length is also analyzed.

DNA↗

PubMed2001

Trajectories in phase diagrams, growth processes, and computational complexity: how search algorithms solve the 3-satisfiability problem.

Decision and optimization problems typically fall into one of two categories for any particular solving algorithm. The problem is either solved quickly (easy) or demands an impractically long computational effort (hard). Here we show that some characteristic parameters of problems can be tracked during a run of the algorithm defining a trajectory through the parameter space. Focusing on 3-satisfiability, a recognized representative of hard problems, we analyze trajectories generated by search algorithms. These trajectories can cross well-defined phases, corresponding to domains of easy or hard instances, and allow one to successfully predict the times of resolution.

Journal Article↗

PubMed1996