Le caractère sérieux dans la procédure civile et le contentieux administratif

Longtemps cantonnée à la seule procédure administrative, tout au moins dans les textes, l'exigence d'un caractère sérieux apparaît dans un grand nombre de mécanismes récents du contentieux judiciaire, pour peu qu'ils soient atypiques ou dérogatoires. C'est le cas de la non-admission des pourvois en cassation, de la question pour avis, de la question prioritaire de constitutionnalité, mais aussi, notamment sursis à exécution des jugements du juge de l'exécution. Les textes l'emploient au sujet d'un moyen ou d'une difficulté. Une étude comparée de la notion entre la procédure civile et le contentieux administratif, mais aussi entre les différentes règles parait donc utile. L'analyse révèle que loin d'être uniforme, cette notion emprunte des acceptions variées, adaptées à chaque dispositif. Les juges ne se sont pas contentés d'un emploi cantonné à une simple marge d'appréciation. A plusieurs reprises, ils ont déterminé une nature ou un degré déduit de la raison d'être de la règle et de l'office qu'ils pensent être le leur. Ces différences, qui se sont logiquement traduites par une pluralité des significations, révèlent toutes les nuances d'une notion apparemment monolithique

Integration of Gravitational Torques in Cerebellar Pathways Allows for the Dynamic Inverse Computation of Vertical Pointing Movements of a Robot Arm

Several authors suggested that gravitational forces are centrally represented in the brain for planning, control and sensorimotor predictions of movements. Furthermore, some studies proposed that the cerebellum computes the inverse dynamics (internal inverse model) whereas others suggested that it computes sensorimotor predictions (internal forward model).This study proposes a model of cerebellar pathways deduced from both biological and physical constraints. The model learns the dynamic inverse computation of the effect of gravitational torques from its sensorimotor predictions without calculating an explicit inverse computation. By using supervised learning, this model learns to control an anthropomorphic robot arm actuated by two antagonists McKibben artificial muscles. This was achieved by using internal parallel feedback loops containing neural networks which anticipate the sensorimotor consequences of the neural commands. The artificial neural networks architecture was similar to the large-scale connectivity of the cerebellar cortex. Movements in the sagittal plane were performed during three sessions combining different initial positions, amplitudes and directions of movements to vary the effects of the gravitational torques applied to the robotic arm. The results show that this model acquired an internal representation of the gravitational effects during vertical arm pointing movements.This is consistent with the proposal that the cerebellar cortex contains an internal representation of gravitational torques which is encoded through a learning process. Furthermore, this model suggests that the cerebellum performs the inverse dynamics computation based on sensorimotor predictions. This highlights the importance of sensorimotor predictions of gravitational torques acting on upper limb movements performed in the gravitational field

Simulation Modifies Prehension: Evidence for a Conjoined Representation of the Graspable Features of an Object and the Action of Grasping It

Movement formulas, engrams, kinesthetic images and internal models of the body in action are notions derived mostly from clinical observations of brain-damaged subjects. They also suggest that the prehensile geometry of an object is integrated in the neural circuits and includes the object's graspable characteristics as well as its semantic properties. In order to determine whether there is a conjoined representation of the graspable characteristics of an object in relation to the actual grasping, it is necessary to separate the graspable (low-level) from the semantic (high-level) properties of the object. Right-handed subjects were asked to grasp and lift a smooth 300-g cylinder with one hand, before and after judging the level of difficulty of a “grasping for pouring” action, involving a smaller cylinder and using the opposite hand. The results showed that simulated grasps with the right hand exert a direct influence on actual motor acts with the left hand. These observations add to the evidence that there is a conjoined representation of the graspable characteristics of the object and the biomechanical constraints of the arm

Foscolo critico

Il volume, primo della collana open access dei "Quaderni di Gargnano", ospita i contributi presentati al XV Convegno internazionale di Letteratura italiana "Gennaro Barbarisi", tenutosi a Gargnano del Garda dal 24 al 26 settembre 2012. Il "Quaderno", dedicato al Foscolo critico, accoglie contributi di Giovanni Biancardi, Arnaldo Bruni, Andrea Campana, Massimo Castellozzi, Gustavo Costa, Alfredo Cottignoli, Christian Del Vento, Sandro Gentili, Franco Longoni, Ilaria Mangiavacchi, Donatella Martinelli, Giuseppe Natale, Enzo Neppi, Matteo Palumbo, Elena Parrini Cantini, Chiara Piola Caselli. \uc8 aperto da una Prefazione di Claudia Berra, Paolo Borsa e Giulia Ravera.This volume on "Foscolo critico" is the first volume of the "Quaderni di Gargnano", an open access book series which publishes the Proceedings of the "Gennaro Barbarisi" International Conferences on Italian Literature, held in Gargnano del Garda. It contains contributions by Giovanni Biancardi, Arnaldo Bruni, Andrea Campana, Massimo Castellozzi, Gustavo Costa, Alfredo Cottignoli, Christian Del Vento, Sandro Gentili, Franco Longoni, Ilaria Mangiavacchi, Donatella Martinelli, Giuseppe Natale, Enzo Neppi, Matteo Palumbo, Elena Parrini Cantini, Chiara Piola Caselli, preceded by a Preface by the Editor: Claudia Berra, Paolo Borsa, Giulia Ravera

The Inactivation Principle: Mathematical Solutions Minimizing the Absolute Work and Biological Implications for the Planning of Arm Movements

An important question in the literature focusing on motor control is to determine which laws drive biological limb movements. This question has prompted numerous investigations analyzing arm movements in both humans and monkeys. Many theories assume that among all possible movements the one actually performed satisfies an optimality criterion. In the framework of optimal control theory, a first approach is to choose a cost function and test whether the proposed model fits with experimental data. A second approach (generally considered as the more difficult) is to infer the cost function from behavioral data. The cost proposed here includes a term called the absolute work of forces, reflecting the mechanical energy expenditure. Contrary to most investigations studying optimality principles of arm movements, this model has the particularity of using a cost function that is not smooth. First, a mathematical theory related to both direct and inverse optimal control approaches is presented. The first theoretical result is the Inactivation Principle, according to which minimizing a term similar to the absolute work implies simultaneous inactivation of agonistic and antagonistic muscles acting on a single joint, near the time of peak velocity. The second theoretical result is that, conversely, the presence of non-smoothness in the cost function is a necessary condition for the existence of such inactivation. Second, during an experimental study, participants were asked to perform fast vertical arm movements with one, two, and three degrees of freedom. Observed trajectories, velocity profiles, and final postures were accurately simulated by the model. In accordance, electromyographic signals showed brief simultaneous inactivation of opposing muscles during movements. Thus, assuming that human movements are optimal with respect to a certain integral cost, the minimization of an absolute-work-like cost is supported by experimental observations. Such types of optimality criteria may be applied to a large range of biological movements

Assessing the uncertainties of model estimates of primary productivity in the tropical Pacific Ocean

Author Posting. © Elsevier B.V., 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Marine Systems 76 (2009): 113-133, doi:10.1016/j.jmarsys.2008.05.010.Depth-integrated primary productivity (PP) estimates obtained from satellite ocean color based models (SatPPMs) and those generated from biogeochemical ocean general circulation models (BOGCMs) represent a key resource for biogeochemical and ecological studies at global as well as regional scales. Calibration and validation of these PP models are not straightforward, however, and comparative studies show large differences between model estimates. The goal of this paper is to compare PP estimates obtained from 30 different models (21 SatPPMs and 9 BOGCMs) to a tropical Pacific PP database consisting of ~1000 14C measurements spanning more than a decade (1983- 1996). Primary findings include: skill varied significantly between models, but performance was not a function of model complexity or type (i.e. SatPPM vs. BOGCM); nearly all models underestimated the observed variance of PP, specifically yielding too few low PP (< 0.2 gC m-2d-2) values; more than half of the total root-mean-squared model-data differences associated with the satellite-based PP models might be accounted for by uncertainties in the input variables and/or the PP data; and the tropical Pacific database captures a broad scale shift from low biomass-normalized productivity in the 1980s to higher biomass-normalized productivity in the 1990s, which was not successfully captured by any of the models. This latter result suggests that interdecadal and global changes will be a significant challenge for both SatPPMs and BOGCMs. Finally, average root-mean-squared differences between in situ PP data on the equator at 140°W and PP estimates from the satellite-based productivity models were 58% lower than analogous values computed in a previous PP model comparison six years ago. The success of these types of comparison exercises is illustrated by the continual modification and improvement of the participating models and the resulting increase in model skill.This research was supported by a grant from the National Aeronautics and Space Agency Ocean Biology and Biogeochemistry program (NNG06GA03G), as well as by numerous other grants to the various participating investigator