Heterogeneity-provoked pulse generation in coupled excitable elements.

Pulse generation in a spatially extended system is studied numerically. Using an array of coupled excitable oscillators, pulse generation is achieved by introducing a parametric heterogeneity between the two partitions of the array. The profile of the propagating pulses can be regulated using the parameter mismatch between these two partitions.

Stochastic resonance with a mesoscopic reaction-diffusion system.

In a mesoscopic reaction-diffusion system with an Oregonator reaction model, we show that intrinsic noise can drive a resonant stable pattern in the presence of the initial subthreshold perturbations. Both spatially periodic and aperiodic stochastic resonances are demonstrated by employing the Gillespies stochastic simulation algorithm. The mechanisms for these phenomena are discussed.

Chemical activity induces dynamical force with global structure in a reaction-diffusion-convection system.

We found a rotating global structure induced by the dynamical force of local chemical activity in a thin solution layer of excitable Belousov-Zhabotinsky reaction coupled with diffusion. The surface flow and deformation associated with chemical spiral waves (wavelength about 1 mm) represents a global unidirectional structure and a global tilt in the entire Petri dish (100 mm in diameter), respectively. For these observations, we scanned the condition of hierarchal pattern selection.

Stationary pattern formation in a discrete excitable system with strong inhibitory coupling.

We study a discrete model described by coupled excitable elements following the monostable FitzHugh-Nagumo equations. Our model has a weakly coupled activator and a strongly coupled inhibitor. For two-coupled excitable elements, we show that the trivial state always exists stably, while nontrivial stable states appear depending on the coupling strengths.

Coexisting stable patterns in a reaction-diffusion system with reversible Gray-Scott dynamics.

It is unlikely that a dissipative reaction-diffusion system exhibits static domains composed of different pattern elements. So far as we know, there is only one exception in the energy conserving system: the generalized Swift-Hohenberg (GSH) system [M'F. Hilali, Phys.

Entropy production in a two-dimensional reversible Gray-Scott system.

The entropy production sigma is calculated in the time evolution processes toward a Turing-like pattern and a chaotic pattern in a two-dimensional reaction-diffusion system. The contributions of reaction and diffusion to the entropy production are evaluated separately. Though its contribution to total sigma is about 5%, the entropy production in diffusion foretells the moving direction of the dots (reaction spots) and the line-shaped patterns.

'Initial state' coordinations reproduce the instant flexibility for human walking.

An important feature of human locomotor control is the instant adaptability to unpredictable changes of conditions surrounding the locomotion. Humans, for example, can seamlessly adapt their walking gait following a sudden ankle impairment (e.g.

Three-variable reversible Gray-Scott model.

Even though the field of nonequilibrium thermodynamics has been popular and its importance has been suggested by Demirel and Sandler [J. Phys. Chem.