482 research outputs found
A proposito delle questioni di legittimità costituzionale sulla legge n. 18/2015 e della responsabilità dei magistrati in generale
L’articolo analizza le problematiche di natura costituzionale connesse alla nuova legge sulla responsabilità civile dei magistrati. Dopo avere illustrato le novità introdotte dalla l. n. 18/2015, l’autore passa a prendere in esame la giurisprudenza costituzionale in materia di responsabilità dei magistrati, per poi affrontare la fondatezza delle questioni di legittimità costituzionale sulla nuova legge. La conclusione è nel senso che la nuova legge sia legittima sul piano costituzionale
I "decostituiti" de "La Sapienza": Santi Romano, Maurizio Maraviglia e Carlo Costamagna
Il contributo analizza le figure dei tre giuspubblicisti dell'Università di Roma "La Sapienza" (Costamagna, Maraviglia e Romano) sottoposti a procedimento di epurazione dopo la cadutra del fascismo
Giurisdizione costituzionale, Corti sovranazionali e giudici comuni. Considerazioni a proposito del dialogo tra corti
L’articolo analizza i rapporti tra Corte costituzionale, Corti sovranazionali e giudici comuni, nella prospettiva del dialogo giudiziale. La tesi esposta è che il dialogo tra corti è la logica conseguenza della espansione del potere giudiziario, e del superamento della idea del giudice come bouche de la loi. L’autore prende in esame anche i casi in cui il dialogo tra corti si è rivelato mancante, insufficiente o contraddittorio. La conclusione, tuttavia, è che, anche quando sembrano divergere o dissentire, i giudici comunque dialogano sempre tra loro.The article analyzes the relationship between the Constitutional Court, supranational courts and ordinary courts, in the judicial dialogue perspective. The thesis is that the dialogue between the courts is the logical consequence of the expansion of judicial power, and the overcoming of the idea of the judge as bouche de la loi. The author also examines the cases in which the dialogue between courts is missing, insufficient or contradictory. The conclusion, however, is that even when they seem to diverge or disagree, the judges always talk to each other
Impact of atrial fibrillation on the cardiovascular system through a lumped-parameter approach
Atrial fibrillation (AF) is the most common arrhythmia affecting millions of
people in the Western countries and, due to the widespread impact on the
population and its medical relevance, is largely investigated in both clinical
and bioengineering sciences. However, some important feedback mechanisms are
still not clearly established. The present study aims at understanding the
global response of the cardiovascular system during paroxysmal AF through a
lumped-parameter approach, which is here performed paying particular attention
to the stochastic modeling of the irregular heartbeats and the reduced
contractility of the heart. AF can be here analyzed by means of a wide number
of hemodynamic parameters and avoiding the presence of other pathologies, which
usually accompany AF. Reduced cardiac output with correlated drop of ejection
fraction and decreased amount of energy converted to work by the heart during
blood pumping, as well as higher left atrial volumes and pressures are some of
the most representative results aligned with the existing clinical literature
and here emerging during acute AF. The present modeling, providing new insights
on cardiovascular variables which are difficult to measure and rarely reported
in literature, turns out to be an efficient and powerful tool for a deeper
comprehension and prediction of the arrythmia impact on the whole
cardiovascular system.Comment: 16 pages, 8 figures, 2 tables, Medical & Biological Engineering &
Computing, 2014, Print ISSN: 0140-0118, Online ISSN: 1741-044
La giurisdizione durante il regime costituzionale provvisorio e la sua valutazione nella giurisprudenza successiva
L'articolo analizza il ruolo della giurisidizione durante il regime costituzionale provvisorio, evidenziando i profili di continuità tra la giurisprudenza della R.S.I. e quella dello Stato italiano, in ragione della evidente continuità del ceto giudiziario tra Fascismo e Repubblica
Impaired coronary blood flow at higher heart rates during atrial fibrillation: investigation via multiscale modelling
Background. Different mechanisms have been proposed to relate atrial
fibrillation (AF) and coronary flow impairment, even in absence of relevant
coronary artery disease (CAD). However, the underlying hemodynamics remains
unclear. Aim of the present work is to computationally explore whether and to
what extent ventricular rate during AF affects the coronary perfusion.
Methods. AF is simulated at different ventricular rates (50, 70, 90, 110, 130
bpm) through a 0D-1D multiscale validated model, which combines the left
heart-arterial tree together with the coronary circulation. Artificially-built
RR stochastic extraction mimics the \emph{in vivo} beating features. All the
hemodynamic parameters computed are based on the left anterior descending (LAD)
artery and account for the waveform, amplitude and perfusion of the coronary
blood flow.
Results. Alterations of the coronary hemodynamics are found to be associated
either to the heart rate increase, which strongly modifies waveform and
amplitude of the LAD flow rate, and to the beat-to-beat variability. The latter
is overall amplified in the coronary circulation as HR grows, even though the
input RR variability is kept constant at all HRs.
Conclusions. Higher ventricular rate during AF exerts an overall coronary
blood flow impairment and imbalance of the myocardial oxygen supply-demand
ratio. The combined increase of heart rate and higher AF-induced hemodynamic
variability lead to a coronary perfusion impairment exceeding 90-110 bpm in AF.
Moreover, it is found that coronary perfusion pressure (CPP) is no longer a
good measure of the myocardial perfusion for HR higher than 90 bpm.Comment: 8 pages, 5 figures, 3 table
Rate Control Management of Atrial Fibrillation: May a Mathematical Model Suggest an Ideal Heart Rate?
Background. Despite the routine prescription of rate control therapy for
atrial fibrillation (AF), clinical evidence demonstrating a heart rate target
is lacking. Aim of the present study was to run a mathematical model simulating
AF episodes with a different heart rate (HR) to predict hemodynamic parameters
for each situation.
Methods. The lumped model, representing the pumping heart together with
systemic and pulmonary circuits, was run to simulate AF with HR of 50, 70, 90,
110 and 130 bpm, respectively.
Results. Left ventricular pressure increased by 56.7%, from 33.92+-37.56 mmHg
to 53.15+-47.56 mmHg, and mean systemic arterial pressure increased by 27.4%,
from 82.66+-14.04 mmHg to 105.29+-7.63 mmHg, at the 50 and 130 bpm simulations,
respectively. Stroke volume (from 77.45+-8.5 to 39.09+-8.08 mL), ejection
fraction (from 61.1+-4.4 to 39.32+-5.42%) and stroke work (SW, from 0.88+-0.04
to 0.58+-0.09 J) decreased by 49.5, 35.6 and 34.2%, at the 50 and 130 bpm
simulations, respectively. In addition, oxygen consumption indexes (rate
pressure product, RPP, tension time index per minute, TTI/min, and pressure
volume area per minute, PVA/min) increased from the 50 to the 130 bpm
simulation, respectively, by 185.7% (from 5598+-1939 to 15995+-3219 mmHg/min),
55.5% (from 2094+-265 to 3257+-301 mmHg s/min) and 102.4% (from 57.99+-17.9 to
117.37+-25.96 J/min). In fact, left ventricular efficiency (SW/PVA) decreased
from 80.91+-2.91% at 50 bpm to 66.43+-3.72% at the 130 bpm HR simulation.
Conclusion. Awaiting compulsory direct clinical evidences, the present
mathematical model suggests that lower HRs during permanent AF relates to
improved hemodynamic parameters, cardiac efficiency, and lower oxygen
consumption.Comment: 9 page
Alteration of cerebrovascular haemodynamic patterns due to atrial fibrillation: an in silico investigation
There has recently been growing evidence that atrial fibrillation (AF), the
most common cardiac arrhythmia, is independently associated with the risk of
dementia. This represents a very recent frontier with high social impact for
the number of individuals involved and for the expected increase in AF
incidence in the next 40 years. Although a number of potential haemodynamic
processes, such as microembolisms, altered cerebral blood flow, hypoperfusion
and microbleeds, arise as connecting links between the two pathologies, the
causal mechanisms are far from clear. An in silico approach is proposed that
combines in sequence two lumped-parameter schemes, for the cardiovascular
system and the cerebral circulation. The systemic arterial pressure is obtained
from the cardiovascular system and used as the input for the cerebral
circulation, with the aim of studying the role of AF on the cerebral
haemodynamics with respect to normal sinus rhythm (NSR), over a 5000 beat
recording. In particular, the alteration of the haemodynamic (pressure and
flowrate) patterns in the microcirculation during AF is analysed by means of
different statistical tools, from correlation coefficients to autocorrelation
functions, crossing times, extreme values analysis and multivariate linear
regression models. A remarkable signal alteration, such as a reduction in
signal correlation (NSR, about 3 s; AF, less than 1 s) and increased
probability (up to three to four times higher in AF than in NSR) of extreme
value events, emerges for the peripheral brain circulation. The described
scenario offers a number of plausible cause-effect mechanisms that might
explain the occurrence of critical events and the haemodynamic links relating
to AF and dementia.Comment: 13 pages, 9 Figures, 3 Table
Stability of the Duality Gap in Linear Optimization
In this paper we consider the duality gap function g that measures the difference between the optimal values of the primal problem and of the dual problem in linear programming and in linear semi-infinite programming. We analyze its behavior when the data defining these problems may be perturbed, considering seven different scenarios. In particular we find some stability results by proving that, under mild conditions, either the duality gap of the perturbed problems is zero or + ∞ around the given data, or g has an infinite jump at it. We also give conditions guaranteeing that those data providing a finite duality gap are limits of sequences of data providing zero duality gap for sufficiently small perturbations, which is a generic result.This research was partially supported by MINECO of Spain and FEDER of EU, Grant MTM2014-59179-C2-01 and SECTyP-UNCuyo Res. 4540/13-R
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