399 research outputs found
IL COORDINAMENTO FRA AMMINISTRAZIONE COMUNITARIA DIRETTA E INDIRETTA
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
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
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
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Selected ground-water data for Yucca Mountain region, southern Nevada and eastern California, through December 1995
The US Geological Survey, in support of the U.S. Department of Energy, Yucca Mountain Site Characterization Project, collects, compiles, and summarizes hydrologic data in the Yucca Mountain region. The data are collected to allow assessments of ground-water resources during studies to determine the potential suitability of Yucca Mountain for storing high-level nuclear waste. Data on ground-water levels at 36 sites, ground-water discharge at 6 sites, and groundwater withdrawals within Crater Flat, Jackass Flats, Mercury Valley, and the Amargosa Desert are presented for calendar year 1995. Data collected prior to 1995 are graphically presented and data collected by other agencies (or as part of other programs) are included to further indicate variations of ground-water levels, discharges, and withdrawals through time. A statistical summary of ground-water levels at seven wells in Jackass Flats is presented to indicate potential effects of ground-water withdrawals in support of US Department of Energy activities near Yucca Mountain. The statistical summary includes the number of measurements, the maximum, minimum, and median water-level altitudes, and the average deviation of measured water-level altitudes for selected baseline periods and for calendar years 1992-95. Compared with baseline periods for the seven wells, median water levels for calendar year 1995 were slightly lower (0.1 to 0.2 foot) at two principal water-supply wells and one observation well nearest to those supply wells, slightly higher (0.2 to 0.5 foot) at three other wells in Jackass Flats, and unchanged at the seventh well
Intrinsic gain modulation and adaptive neural coding
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
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
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
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 βschedule length effectβ). 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: βframing,β wherein equivalent options are treated differently depending on the context in which they are presented, and the βsunk costβ 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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