Search results for " NOISE"

Evidence of stochastic resonance in the mating behavior of Nezara viridula (L.)

2008

We investigate the role of the noise in the mating behavior between individuals of Nezara viridula (L.), by analyzing the temporal and spectral features of the non-pulsed type female calling song emitted by single individuals. We have measured the threshold level for the signal detection, by performing experiments with the calling signal at different intensities and analyzing the insect response by directionality tests performed on a group of male individuals. By using a sub-threshold signal and an acoustic Gaussian noise source, we have investigated the insect response for different levels of noise, finding behavioral activation for suitable noise intensities. In particular, the percentage…

Noise Induced Phenomena in the Dynamics of Two Competing Species

2015

Noise through its interaction with the nonlinearity of the living systems can give rise to counter-intuitive phenomena. In this paper we shortly review noise induced effects in different ecosystems, in which two populations compete for the same resources. We also present new results on spatial patterns of two populations, while modeling real distributions of anchovies and sardines. The transient dynamics of these ecosystems are analyzed through generalized Lotka-Volterra equations in the presence of multiplicative noise, which models the interaction between the species and the environment. We find noise induced phenomena such as quasi-deterministic oscillations, stochastic resonance, noise …

Deformation Quantization by Moyal Star-Product and Stratonovich Chaos

2012

We make a deformation quantization by Moyal star-product on a space of functions endowed with the normalized Wick product and where Stratonovich chaos are well defined.

Numerical simulation of resonant activation in a fluctuating metastable model system

1998

We study the escape time from a metastable overdamped model system in the presence of two noise sources: a white noise and a random telegraph noise. The random telegraph noise controls the height of the potential barrier of the metastable system while the white noise mimics the presence of a given temperature. We report on numerical simulations about: (i) the average residence time of the system in the metastable state; (ii) the probability density function (PDF) of the residence time at various values of the correlation time T c of the random telegraph noise. Resonant activation is observed in the dynamics of the investigated system. The PDF shows different shapes for different values of τ…

La “Stimolazione transcranica Random Noise” (tRNS) e la riabilitazione motoria dell’arto superiore nel paziente in fase subacuta di ictus ischemico.

"RANDOM NOISE TRANSCRANIAL STIMULATION" (TRNS) AND MOTOR REHABILITATION OF THE UPPER LIMB IN SUBACUTE ISCHEMIC STROKE PATIENTS. BACKGROUND Upper limb impairment is a common outcome after stroke. New rehabilitative interventions partially failed to show a superior effect compared to standard therapy. The present study focuses on the effect of tNRS in the sub-acute stage after stroke. The primary aim is to evaluate the combined use of TRNS with the GRASP in subacute ischemic stroke patients. METHODS A double-blind RCT, approved by local committee, was performed. Patients with upper-limb impairment were recruited 1 to 6 weeks after stroke. Participants were randomly allocated to two groups: GR…

Bimodal Approach for Noise Figures of Merit Evaluation in Quantum-Limited Josephson Traveling Wave Parametric Amplifiers

2022

The advent of ultra-low noise microwave amplifiers revolutionized several research fields demanding quantum-limited technologies. Exploiting a theoretical bimodal description of a linear phase-preserving amplifier, in this contribution we analyze some of the intrinsic properties of a model architecture (i.e., an rf-SQUID based Josephson Traveling Wave Parametric Amplifier) in terms of amplification and noise generation for key case study input states (Fock and coherents). Furthermore, we present an analysis of the output signals generated by the parametric amplification mechanism when thermal noise fluctuations feed the device.

EFFECT OF LOW-FREQUENCY NOISE ON ADIABATIC PASSAGE IN A SUPERCONDUCTING NANOCIRCUIT

2011

Recent experiments have demonstrated coherent phenomena in three-level systems based on superconducting nanocircuits. This opens the possibility to detect Stimulated Raman Adiabatic Passage (STIRAP) in artificial atoms. Low-fequency noise (often 1/f) is one of the main sources of decoherence in these systems, and we study its effect on the transfer efficiency. We propose a way to analyze low frequency fluctuations in terms of fictitious correlated fluctuations of external parameters. We discuss a specific implementation, namely the Quantronium setup of a Cooper-pair box, showing that optimizing the trade-off between efficient coupling and protection against noise may allow us to observe co…

Lifetime of the superconductive state in short and long Josephson junctions

2008

We study the transient statistical properties of short and long Josephson junctions under the influence of thermal and correlated fluctuations. In particular, we investigate the lifetime of the superconductive metastable state finding the presence of noise induced phenomena. For short Josephson junctions we investigate the lifetime as a function both of the frequency of the current driving signal and the noise intensity and we find how these noise-induced effects are modified by the presence of a correlated noise source. For long Josephson junctions we integrate numerically the sine-Gordon equation calculating the lifetime as a function of the length of the junction both for inhomogeneous a…

PROPOSALS FOR ENVIRONMENTAL NOISE MANAGEMENT BOOST AT A NATIONAL LEVEL IN THE EUROPEAN UNION MEMBER STATES

2017

Environmental noise is currently becoming one of the most dominant types of environmental pollution. The effects of environmental noise closely correlate with quality of life especially regarding the physical and psychological health of inhabitants, social and economic costs, and thus also impacting the sustainable development of a country. Environmental noise management, therefore, is one of the most necessary and exigent aspects of environmental pollution management governance. The management of noise need to be developed in a comprehensive, integrative and cross-sectorial way, and appropriate methods and approaches for the management of overall noise impacts need to be found to deal with…

Surpassing digital holography limits by lensless object scanning holography.

2012

We present lensless object scanning holography (LOSH) as a fully lensless method, capable of improving image quality in reflective digital Fourier holography, by means of an extremely simplified experimental setup. LOSH is based on the recording and digital post-processing of a set of digital lensless holograms and results in a synthetic image with improved resolution, field of view (FOV), signal-to-noise ratio (SNR), and depth of field (DOF). The superresolution (SR) effect arises from the generation of a synthetic aperture (SA) based on the linear movement of the inspected object. The same scanning principle enlarges the object FOV. SNR enhancement is achieved by speckle suppression and c…