Search results for " MODELLI"

Modelli di consumo e nuovo paradigma della sostenibilità: i Gruppi di Acquisto Solidale in Sicilia

2010

European society, with its steadily increased welfare levels, is not only concerned about food (safety, prices), but also on other aspects such as biodiversity loss, landscape degradation, pollution of water, soil and atmosphere. To a large extent these concerns can be translated into a wider concept named sustainable development defined as a normative concept by Morgan and Sonnino (2008). Sustainability in the food chain means approaching a new emerging vision of a sustainable agro-food system introducing an institutional dimension to take into account. Among different attempts to conjugate such concepts, there is one that is taking place in many Regions of Italy. In the last years spontan…

La dimensione spaziale nella relazione tra cambiamento della popolazione e demografia di impresa

2014

Voltage drop across Josephson junctions for L\'evy noise detection

2020

We propose to characterize L\'evy-distributed stochastic fluctuations through the measurement of the average voltage drop across a current-biased Josephson junction. We show that the noise induced switching process in the Josephson washboard potential can be exploited to reveal and characterize L\'evy fluctuations, also if embedded in a thermal noisy background. The measurement of the average voltage drop as a function of the noise intensity allows to infer the value of the stability index that characterizes L\'evy-distributed fluctuations. An analytical estimate of the average velocity in the case of a L\'evy-driven escape process from a metastable state well agrees with the numerical calc…

Enhancement of stability in systems with metastable states

2007

The investigation of noise‐induced phenomena in far from equilibrium systems is one of the approach used to understand the behaviour of physical and biological complex systems. Metastability is a generic feature of many nonlinear systems, and the problem of the lifetime of metastable states involves fundamental aspects of nonequilibrium statistical mechanics. The enhancement of the life‐time of metastable states through the noise enhanced stability effect and the role played by the resonant activation phenomenon will be discussed in models of interdisciplinary physics: (i) Ising model (ii) Josephson junction; (iii) stochastic FitzHugh‐Nagumo model; (iv) a population dynamics model, and (v) …

Noise stabilization effects in models of interdisciplinary physics

2009

Metastability is a generic feature of many nonlinear systems, and the problem of the lifetime of metastable states involves fundamental aspects of nonequilibrium statistical mechanics. The investigation of noise-induced phenomena in far from equilibrium systems is one of the approaches used to understand the behaviour of physical and biological complex systems. The enhancement of the lifetime of metastable states through the noise enhanced stability effect and the role played by the resonant activation phenomenon will be discussed in models of interdisciplinary physics: (i) polymer translocation dynamics; (ii) transient regime of FitzHugh-Nagumo model; (iii) market stability in a nonlinear …

Stabilization Effects of Dichotomous Noise on the Lifetime of theSuperconducting State in a Long Josephson Junction

2015

We investigate the superconducting lifetime of a long overdamped current-biased Josephson junction, in the presence of telegraph noise sources. The analysis is performed by randomly choosing the initial condition for the noise source. However, in order to investigate how the initial value of the dichotomous noise affects the phase dynamics, we extend our analysis using two different fixed initial values for the source of random fluctuations. In our study, the phase dynamics of the Josephson junction is analyzed as a function of the noise signal intensity, for different values of the parameters of the system and external driving currents. We find that the mean lifetime of the superconductive…

B-K-parameter from N-f=2 twisted mass lattice QCD

2011

We present an unquenched N-f = 2 lattice computation of the B-K parameter which controls K-0 - (K) over bar (0) oscillations. A partially quenched setup is employed with two maximally twisted dynamical (sea) light Wilson quarks, and valence quarks of both the maximally twisted and the Osterwalder-Seiler variety. Suitable combinations of these two kinds of valence quarks lead to a lattice definition of the B-K parameter which is both multiplicatively renormalizable and O(a) improved. Employing the nonperturbative RI-MOM scheme, in the continuum limit and at the physical value of the pion mass we get B-K(RGI) = 0.729 +/- 0.030, a number well in line with the existing quenched and unquenched d…

Membrane Bioreactors for wastewater reuse: Respirometric assessment of biomass activity during a two year survey

2018

Abstract Stricter effluent limits, water shortage conditions, land availability requires today even more the needs of advanced wastewater treatments. Attractive solutions come from membrane bioreactors (MBR), Integrated Fixed Film Activated Sludge (IFAS) or combinations (i.e., IFAS-MBRs). One crucial aspect for the applicability of this overall new technology, compared to the conventional activated sludge systems, is the lack of knowledge for design and manage (e.g., kinetic constants, optimal operative conditions etc.). In view of the above frame, the aim of the present study was to assess the kinetic and stoichiometric parameters of bacterial species in MBRs by means of respirometric tech…

Fostering entrepreneurial learning processes through Dynamic Start-up business model simulators

2018

Abstract Entrepreneurial learning is a critical process in realizing the success or failure of a new business venture, as it implies that would-be entrepreneurs acquire those strategic management competencies required to start and manage a new business. Actually, statistics on start-up survival/failure rate reveal that the main reasons for failure are related to a lack of entrepreneurial competencies of start-uppers. This paper argues that combining Business Model representation schemas with System Dynamics modelling may support potential start-up entrepreneurs in learning and experimenting how to turn a business idea into a real firm. System Dynamics modelling is a methodology that allows …

The Complementary effect of internal learning capacity and absorptive capacity on performance: the mediating role of innovation capacity

2011

Organisations are finding it increasingly more difficult to keep abreast with the pace of change. The continuous rise in the number of business opportunities and the increase in global competition require firms to combine internal and external learning processes to renew and reconfigure existing capabilities and knowledge to enable them to meet environmental demands and to innovate. This study aims to unravel the complex linkage between internal learning capacity and absorptive capacity and at exploring the joint effect of both knowledge generation processes on innovation capacity. This study also proposes innovation capacity as an antecedent of business performance. Using data from 952 ind…