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B Bassetti

Publications and source records attributed to B Bassetti.

3 recordsLinked to original sources
PubMed2005

Logic backbone of a transcription network.

A great part of the effort in the study of coarse-grained models of transcription networks concentrates on their dynamical features. In this Letter, we consider their equilibrium properties, showing that the backbone underlying the dynamic descriptions is an optimization problem. It involves N variables, the gene expression levels, and M constraints, the effects of transcriptional regulation. In the case of Boolean variables and constraints, we investigate the structure of the solutions and derive phase diagrams. Notably, the model exhibits a connectivity transition between a regime of simple gene control, where the input genes control O(1) other genes, and a regime of complex control, where some core input genes control O(N) others.

Algorithms↗
PubMed2003

Metachronal waves for deterministic switching two-state oscillators with hydrodynamic interaction.

We employ a model system, called rowers, as a generic physical framework to define the problem of the coordinated motion of cilia (the metachronal wave) as a far from equilibrium process. Rowers are active (two-state) oscillators in a low Reynolds number fluid, and interact solely through the forces of hydrodynamic origin. In this work, we consider the case of fully deterministic dynamics, find analytical solutions of the equation of motion in the long-wavelength (continuum) limit, and investigate numerically the short-wavelength limit. We prove the existence of metachronal waves below a characteristic wavelength. Such waves are unstable and become stable only if the sign of the coupling is reversed. We also find that with normal hydrodynamic interaction, the metachronal pattern has the form of stable trains of traveling wave packets sustained by the onset of anti-coordinated beating of consecutive rowers.

Journal Article↗