399 research outputs found

    IL COORDINAMENTO FRA AMMINISTRAZIONE COMUNITARIA DIRETTA E INDIRETTA

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    The research examines the relations between the direct and indirect European administration in medias res, concentrating its attention away from the framework introduced following the adoption of the Treaty of Lisbon amending the Treaty on European Union and the Treaty establishing the European Community, entered into force on 1 December 2009. After a re-reading of the concepts of 'coordination' and 'executive function', the work reviews the procedures for exercising the executive European power updated by the treaties and some methods of coordination to which it is resorted in these first years of activities, instruments that seem to have favored complex and inefficient plots of skills in place of definitive solutions to the common work of the bureaucracy involved from the European administration. In this direction, the work analyzes, e.g., the cases of the management of structural funds, with specific reference to the Italian institution of the Agency for National Cohesion, next to punctual requests from the European Commission, and of the Agency for Cooperation between national energy regulators, particularly with respect to the this body\u2019s powers of direct administration attributed by REMIT discipline. Retrieved, finally, some considerations on the possibility of establishing Partnerships between European and national legal order based on the criteria of hierarchy and on the (new) legitimacy of the European equipment, the work concludes considering the introduction of a European regulation of the administrative procedure, for consequences of structural significance, as a useful tool for coordination between the various forms of implementing EU law

    Brevi considerazioni su un non creduto conflitto tra spending rewiev e decreto inconferibilità

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    A fronte di un paventato contrasto tra l\u2019articolo 4, commi 4 e 5, del decreto-legge n. 95 del 2012, sulla composizione dei consigli di amministrazione delle societ\ue0 controllate o totalmente partecipate dalle pubbliche Amministrazioni, e la disciplina di recente introduzione, ad opera del decreto legislativo n. 39 del 2013, in materia di inconferibilit\ue0 e incompatibilit\ue0 di incarichi presso le medesime Amministrazioni e gli enti privati in controllo pubblico, si evidenzia una lettura coerente delle due disposizioni che consenta la nomina dei vertici e degli organi delle societ\ue0 considerate senza creare impedimenti alla gestione dell'attivit\ue0 d'impresa

    Nonlinear diffusion & thermo-electric coupling in a two-variable model of cardiac action potential

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    This work reports the results of the theoretical investigation of nonlinear dynamics and spiral wave breakup in a generalized two-variable model of cardiac action potential accounting for thermo-electric coupling and diffusion nonlinearities. As customary in excitable media, the common Q10 and Moore factors are used to describe thermo-electric feedback in a 10-degrees range. Motivated by the porous nature of the cardiac tissue, in this study we also propose a nonlinear Fickian flux formulated by Taylor expanding the voltage dependent diffusion coefficient up to quadratic terms. A fine tuning of the diffusive parameters is performed a priori to match the conduction velocity of the equivalent cable model. The resulting combined effects are then studied by numerically simulating different stimulation protocols on a one-dimensional cable. Model features are compared in terms of action potential morphology, restitution curves, frequency spectra and spatio-temporal phase differences. Two-dimensional long-run simulations are finally performed to characterize spiral breakup during sustained fibrillation at different thermal states. Temperature and nonlinear diffusion effects are found to impact the repolarization phase of the action potential wave with non-monotone patterns and to increase the propensity of arrhythmogenesis

    Intrinsic gain modulation and adaptive neural coding

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    In many cases, the computation of a neural system can be reduced to a receptive field, or a set of linear filters, and a thresholding function, or gain curve, which determines the firing probability; this is known as a linear/nonlinear model. In some forms of sensory adaptation, these linear filters and gain curve adjust very rapidly to changes in the variance of a randomly varying driving input. An apparently similar but previously unrelated issue is the observation of gain control by background noise in cortical neurons: the slope of the firing rate vs current (f-I) curve changes with the variance of background random input. Here, we show a direct correspondence between these two observations by relating variance-dependent changes in the gain of f-I curves to characteristics of the changing empirical linear/nonlinear model obtained by sampling. In the case that the underlying system is fixed, we derive relationships relating the change of the gain with respect to both mean and variance with the receptive fields derived from reverse correlation on a white noise stimulus. Using two conductance-based model neurons that display distinct gain modulation properties through a simple change in parameters, we show that coding properties of both these models quantitatively satisfy the predicted relationships. Our results describe how both variance-dependent gain modulation and adaptive neural computation result from intrinsic nonlinearity.Comment: 24 pages, 4 figures, 1 supporting informatio

    Possible black universes in a brane world

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    A black universe is a nonsingular black hole where, beyond the horizon, there is an expanding, asymptotically isotropic universe. Such spherically symmetric configurations have been recently found as solutions to the Einstein equations with phantom scalar fields (with negative kinetic energy) as sources of gravity. They have a Schwarzschild-like causal structure but a de Sitter infinity instead of a singularity. It is attempted to obtain similar configurations without phantoms, in the framework of an RS2 type brane world scenario, considering the modified Einstein equations that describe gravity on the brane. By building an explicit example, it is shown that black-universe solutions can be obtained there in the presence of a scalar field with positive kinetic energy and a nonzero potential.Comment: 8 pages, 5 figures, gc styl

    A Fokker-Planck formalism for diffusion with finite increments and absorbing boundaries

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    Gaussian white noise is frequently used to model fluctuations in physical systems. In Fokker-Planck theory, this leads to a vanishing probability density near the absorbing boundary of threshold models. Here we derive the boundary condition for the stationary density of a first-order stochastic differential equation for additive finite-grained Poisson noise and show that the response properties of threshold units are qualitatively altered. Applied to the integrate-and-fire neuron model, the response turns out to be instantaneous rather than exhibiting low-pass characteristics, highly non-linear, and asymmetric for excitation and inhibition. The novel mechanism is exhibited on the network level and is a generic property of pulse-coupled systems of threshold units.Comment: Consists of two parts: main article (3 figures) plus supplementary text (3 extra figures

    Modeling the Violation of Reward Maximization and Invariance in Reinforcement Schedules

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    It is often assumed that animals and people adjust their behavior to maximize reward acquisition. In visually cued reinforcement schedules, monkeys make errors in trials that are not immediately rewarded, despite having to repeat error trials. Here we show that error rates are typically smaller in trials equally distant from reward but belonging to longer schedules (referred to as β€œschedule length effect”). This violates the principles of reward maximization and invariance and cannot be predicted by the standard methods of Reinforcement Learning, such as the method of temporal differences. We develop a heuristic model that accounts for all of the properties of the behavior in the reinforcement schedule task but whose predictions are not different from those of the standard temporal difference model in choice tasks. In the modification of temporal difference learning introduced here, the effect of schedule length emerges spontaneously from the sensitivity to the immediately preceding trial. We also introduce a policy for general Markov Decision Processes, where the decision made at each node is conditioned on the motivation to perform an instrumental action, and show that the application of our model to the reinforcement schedule task and the choice task are special cases of this general theoretical framework. Within this framework, Reinforcement Learning can approach contextual learning with the mixture of empirical findings and principled assumptions that seem to coexist in the best descriptions of animal behavior. As examples, we discuss two phenomena observed in humans that often derive from the violation of the principle of invariance: β€œframing,” wherein equivalent options are treated differently depending on the context in which they are presented, and the β€œsunk cost” effect, the greater tendency to continue an endeavor once an investment in money, effort, or time has been made. The schedule length effect might be a manifestation of these phenomena in monkeys
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