L. Romanelli

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We show that an extended system operating in the regime of stochastic resonance can act as a short-term memory device. The system under study is a ring of overdamped bistable oscillators coupled directionally, being each also subject to an external source of Gaussian white noise (the noise sources are independent). A single oscillator is driven by an(More)
Toad ventricles were externally driven by periodic pulses while monophasic action potential (MAP) signals were recorded in seven excised and seven in situ ventricles. As the frequency was slowly increased in steps, the stimulated tissue displayed several dynamic characteristics. Hierarchies of periodic behavior, like phase-locking and period-doubling(More)
X iv :n lin /0 40 50 20 v1 [ nl in .A O ] 1 0 M ay 2 00 4 Coupled Chaotic Oscillators and Its Relation with Artificial Quadrupeds’ Central Pattern Generator Horacio Castellini, ∗ Hilda Cerderira, and Lilia Romanelli † Dpto. de F́ısica, F.C.E.I.A., Pellegini 250, 2000 Rosario International Centre of Theoretical Physics (ICTP), Trieste, Italia Instituto de(More)
Time series of core temperature in golden hamsters with or without access to a running wheel were analyzed using statistical tools and Dynamical Systems theory. Although the statistical analysis did not show any striking difference between the two groups (other than clearer spectra in the case in the animals with access to wheels), a clear dynamical(More)
As a mock-up of synaptic transmission between neurons, we revisit a problem that has recently risen the interest of several authors: the propagation of a low-frequency periodic signal through a chain of one-way coupled bistable oscillators, subject to uncorrelated additive noise. On a numerical study performed in the optimal range of noise intensity for(More)
Transport phenomena in a one-dimensional system of interacting particles is studied. This system is embedded in a periodic and left-right asymmetric potential driven by a force periodic in time and space. When the density (number of particles per site) is an integer, directional current of the particles is collective; that is, it involves the whole system(More)
The topology of the period doubling attractor at the onset of chaos, and its implications for the structure of the power spectrum are discussed. The presence of a seemingly anomalous peak at a non 2" frequency is explained in terms of a topological invariant of the attractor whose systematics is shown to he universal. An experiment on an electronic circuit(More)
The two-oscillator model of human circadian rhythmicity was analyzed when a zeitgeber relative intensity of 1, 0.5, or 0.1 was introduced into the equations. Fourier analysis was compared with dynamic analysis such as attractor reconstruction or Liapunov exponent calculation. After a 50 or 90% reduction in zeitgeber intensity, the dynamics of the system(More)