0000000001333661
AUTHOR
Curcio, Luciano
Environmental noise and nonlinear relaxation in biological systems
We investigate the role of the environmental noise in three biological systems: (i) an ecosystem described by a Verhulst model with a multiplicative Lévy noise; (ii) polymer translocation, and (ii) individuals of Nezara viridula. Specifically the transient dynamics of the Verhulst model perturbed by arbitrary non-Gaussian white noise is investigated as a first biological system. For Cauchy stable noise, exact results for the probability distribution of the population density and nonlinear relaxation are derived. We find a transition induced by the multiplicative Lévy noise, from a trimodal probability distribution to a bimodal probability distribution in asymptotics, and a nonmonotonic beha…
Stochastic resonance effect on the vibratory signals of stink bugs
In this work we investigate the role of the environmental noise in the sexual communication between individuals of the Sicilian green stink bug Nezara Viridula. Our goal is to analyze the spectral features of several types of songs emitted by these insects and to find the amplitude threshold value. Below this value the signal is so weak that no neuronal activation occurs in Nezara Viridula. The presence of activation is revealed by performing directionality tests and observing the behavioral response of the insect in localizing the source of vibratory signals. Afterwards experiments are performed by using a sub-threshold signal added to a white Gaussian noise. The response of the test insec…
Risonanza stocastica non dinamica in una popolazione di Nezara Viridula (L.)
In questo lavoro viene studiato l’effetto del rumore sul comportamento, durante il periodo di accoppiamento, di individui di Nezara viridula (L.). Analizzando la risposta di insetti maschi a segnali sotto soglia, prodotti da individui di sesso femminile, si osserva, in presenza di una sorgente esterna di rumore bianco Gaussiano, un’attivazione “comportamentale”, con un andamento non monotono in funzione dell’intensit`a di rumore, chiara indicazione della presenza di risonanza stocastica non dinamica. Lo studio `e ripetuto utilizzando una sorgente di rumore colorato. Infine, i risultati sperimentali vengono riprodotti attraverso un modello a soglia “morbida”, in cui la funzione di cross-corr…