1,722,444 research outputs found
francesco-mannella/Kick-starting-Concept-Formation-With-Intrinsically-Motivated-Learning: RSTB.2021.0370
No full textThis code si the one used in Mannella F, Tummolini L. 2022 Kick-starting concept formation with intrinsically motivated learning: the grounding by competence acquisition hypothesis. Phil. Trans. R. Soc. B 20210370. https://doi.org/10.1098/rstb.2021.037
francesco-mannella/Selection-of-Cortical-Dynamics-for-Motor-Behaviour 1.0
No full textSource code of the simulations in the paper "Selection of cortical dynamics for motor behaviour by the basal ganglia.
L'approccio transepatico all'albero biliare ed il trattamento della patologia biliare
No full textVengono illustrate le tecniche della radiologia interventistica delle vie biliari,nel trattamento delle patologie sia maligne che benigne, con particolare riguardo alla scelta dei materiali , dei quali vengono descritte le principali caratteristiche
Nomi, cose, città (e contrade). Ricerche onomastiche in Sicilia con gli studenti di Italianistica dell'Università di Palermo
No full textRicerche onomastiche in Sicilia con gli studenti di Italianistica dell'Università di Palermo a cura di Marina Castiglione, Marco Fragale, Pier Luigi Josè Mannella. - Palermo : Centro di studi filologici e linguistici siciliani, 2022. L'ALS per la scuola e il territorio, 5
About the Optimal FPE for Non-linear 1d-SDE with Gaussian Noise: The Pitfall of the Perturbative Approach
No full textThis paper deals with the problem of finding the Fokker Planck Equation (FPE) for the single-time probability density function (PDF) that optimally approximates the single-time PDF of a 1-D Stochastic Differential Equation (SDE) with Gaussian correlated noise. In this context, we tackle two main tasks. First, we consider the case of weak noise and in this framework we give a formal ground to the effective correction, introduced elsewhere (Bianucci and Mannella in J Phys Commun 4(10):105019, 2020, https://doi.org/10.1088/2399-6528/abc54e), to the Best Fokker Planck Equation (a standard “Born-Oppenheimer” result), also covering the more general cases of multiplicative SDE. Second, we consider the FPE obtained by using the Local Linearization Approach (LLA), and we show that a generalized cumulant approach allows an understanding of why the LLA FPE performs so well, even for noises with long (but finite) time scales and large intensities
Stochastic resonance in electrical circuits—I: Conventional stochastic resonance.
Full text linkStochastic resonance (SR), a phenomenon in which a periodic signal in a nonlinear system can be amplified by added noise, is introduced and discussed. Techniques for investigating SR using electronic circuits are described in practical terms. The physical nature of SR, and the explanation of weak-noise SR as a linear response phenomenon, are considered. Conventional SR, for systems characterized by static bistable potentials, is described together with examples of the data obtainable from the circuit models used to test the theory
Matching of separatrix map and resonant dynamics, with application to global chaos onset between separatrices
No full textWe have developed a general method for the description of separatrix chaos, based on the analysis of the separatrix map dynamics. Matching it with the resonant Hamiltonian analysis, we show that, for a given amplitude of perturbation, the maximum width of the chaotic layer in energy may be much larger than it was assumed before. We use the above method to explain the drastic facilitation of global chaos onset in time-periodically perturbed Hamiltonian systems possessing two or more separatrices, previously discovered [S. M. Soskin, O. M. Yevtushenko, and R. Mannella, Phys. Rev. Lett. 90, 174101 (2003)]. The theory well agrees with simulations. We also discuss generalizations and applications. The method may be generalized for single-separatrix cases. The facilitation of global chaos onset may be relevant to a variety of systems, e. g., optical lattices, magnetic and semiconductor superlattices, meandering flows in the ocean, and spinning pendulums. Apart from dynamical transport, it may facilitate noise-induced transitions and the stochastic web formation
Influence of random fluctuations on delayed bifurcations. II. The cases of white and colored additive and multiplicative noise
Full text linkThe influence of noise on the delay of a bifurcation point in the presence of a swept control parameter has been investigated theoretically, by digital simulation and by analog electronic experiment. The results obtained in an earlier paper [N. G. Stocks, R. Mannella, and P. V. E. McClintock, Phys. Rev. A 40, 5361 (989)] have thereby been extended and complemented. In particular, exact analytic expressions have been derived for the time-dependent probability densities P(x,t), and these have been used to obtain the mean first-passage time t*MFPT for x^2(t) to reach a threshold under the influence of Gaussian fluctuations, in several contexts: additive external white noise, additive external exponentially correlated noise, additive internal white noise, additive internal exponentially correlated noise, multiplicative white and colored noise. Based on Zeghlache, Mandel, and Van den Broeck's [Phys. Rev. A 40, 286 (989)] alternative definition of the bifurcation time t*moment in terms of the evolution of the second moment [x^2(t)], an expression is derived for t*moment for the general case of combined additive and multiplicative noises. The calculations are tested by comparison with the results of analog experiments and digital simulations, with which they are shown to be in excellent agreement
Radiologia Interventistica Splenica
No full textGli autori descrivono le caratteristiche principali della Diagnostica Invasiva splenica (biopsia percutanea ecoguidata), e della Radiologia Interventistica sia extravascolare ( drenaggio percutaneo degli ascessi) che vascolare ( embolizzazione arteriosa nei traumi, nell'ipertensione portale, nel morbo di Werlof e nella talassemia
Stochastic resonance in electrical circuits—II: Nonconventional stochastic resonance.
Full text linkStochastic resonance (SR), in which a periodic signal in a nonlinear system can be amplified by added noise, is discussed. The application of circuit modeling techniques to the conventional form of SR, which occurs in static bistable potentials, was considered in a companion paper. Here, the investigation of nonconventional forms of SR in part using similar electronic techniques is described. In the small-signal limit, the results are well described in terms of linear response theory. Some other phenomena of topical interest, closely related to SR, are also treate
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