2,631 research outputs found

    Technological change and industry competitiveness through the evolution of localised comparative advantages - The case of Italy

    Get PDF
    The influence of technological change on industry performances is nowadays being increasingly investigated under the broad category of "national systemic competitiveness". Moreover theoretical works have shown that the relationship between technology and economic performance not only takes different forms in different socio-economic contexts, but is also powerfully influenced by the way that innovation processes evolve over time along strongly localised patterns. The present study is focused on the evolution of trade competitiveness of the manufacturing sector in Italy over the past ten years and addresses to the role played by localised comparative advantages in shaping the model of national competitiveness. The data used in the analysis, drawn by the Enea Observatory on high tech industries, are based on trade statistics at the SITC five digit level and are spatially referenced to the Italy NUT3 regional partition. The effects of localised trade specialisation on manufacturing competitiveness are first assessed through spatial econometric tecniques. Spatial variation in the relationships found is further explored in order to give additional hints on the specific contribution of localised comparative advantages. According to major trends which have recently characterised manufacturing trade competitiveness in Italy, the analysis is expected to bring into evidence significant changes in the contribution of industrial localities to national competitiveness.

    Rapid path to transition via nonlinear localized optimal perturbations in a boundary-layer flow

    Get PDF
    Recent studies have suggested that in some cases transition can be triggered by some purely nonlinear mechanisms. Here we aim at verifying such an hypothesis, looking for a localized perturbation able to lead a boundary-layer flow to a chaotic state, following a nonlinear route. Nonlinear optimal localized perturbations have been computed by means of an energy optimization which includes the nonlinear terms of the Navier- Stokes equations. Such perturbations lie on the turbulent side of the laminar-turbulent boundary, whereas, for the same value of the initial energy, their linear counterparts do not. The evolution of these perturbations toward a turbulent flow involves the presence of streamwise-inclined vortices at short times and of hairpin structures prior to breakdown

    Heat flux dynamics in dissipative cascaded systems

    Get PDF
    We study the dynamics of heat flux in the thermalization process of a pair of identical quantum system that interact dissipatively with a reservoir in a {\it cascaded} fashion. Despite the open dynamics of the bipartite system S is globally Lindbladian, one of the subsystems "sees" the reservoir in a state modified by the interaction with the other subsystem and hence it undergoes a non-Markovian dynamics. As a consequence, the heat flow exhibits a non-exponential time behaviour which can greatly deviate from the case where each party is independently coupled to the reservoir. We investigate both thermal and correlated initial states of SS and show that the presence of correlations at the beginning can considerably affect the heat flux rate. We carry out our study in two paradigmatic cases -- a pair of harmonic oscillators with a reservoir of bosonic modes and two qubits with a reservoir of fermionic modes -- and compare the corresponding behaviours. In the case of qubits and for initial thermal states, we find that the trace distance discord is at any time interpretable as the correlated contribution to the total heat flux.Comment: Final accepted versio
    • 

    corecore