1,886 research outputs found
History and current developments of Holocaust memorials in Germany (including the former GDR)
Paper presented at the Wits History Workshop: The TRC; Commissioning the Past, 11-14 June, 199
Impeded Communication in Frances Burney's Evelina : Distortion, Manipulation and Distance
Publication en ligne par le CELIS (Clermont-Ferrand): http://celis.univ-bpclermont.fr/spip.php?article89
Managing the Flemish dunes: from eco-gardening to mechanical disturbances created by bulldozers
The ‘Conseil Général du Département du Nord’ is the manager of 480ha of Flemish dunes located at the far North of France. These spaces, initially preserved by the action of the ‘Communauté Urbaine de Dunkerque’ are now the property of the ‘Conservatoire de l’Espace Littoral et des Rivages Lacustres’. Characterised by an aelian dynamism and by the winter flooding of their damp depressions, these systems had represented a very high patrimonial richness before man, by these actions (the pumping of the aquifers, the parcelling out of dune massifs, the fixation of sand by plantations, the destruction of rabbits), reduced to nothing the natural expression of perturbations (storms, floods, important sandbanks) and made dune massifs become wastelands and low marshes and dry lawns disappear. The first step for preservation was the in extremis safeguard and the maintenance by secateurs (1989) then by motor scythes (1992) of micro-habitats with a high richness over a 2ha total surface lost in very important pre-forested systems. Rapidly, the objectives of preservation obliged us to put into practice the restoration of natural environments by stripping and clearing the ground (1994 and 1997). But these operations of a large scale (10ha) were always based on a ‘fixist’ and ‘museographical’ approach to the environment (the maintenance of a representative sample of habitats). The management which consists of stopping certain pioneer and post-pioneer stages of vegetation can in fact correspond to a counter-natural step as these dune systems make the proof of a very high dynamism and permanent evolution. Today the management of dune space is done by bulldozers: first the pre-forested vegetation is totally destructed (16ha in 2004) leaving systems of bare sand freely evolving and accepting their spontaneous wastelanding over more than 50% of their surfaces. The return to uncontrolled vegetal dynamism is only accepted if perturbations are periodically created in order to regularly produce the starting or reappearance conditions of the different series of vegetation. The last stage of our managing operations would consist, with a middle-term effect, in reducing the stability of the edging dune row and in favouring the development of wind passages with their devastation or saving effects on the dune we intend to preserve
A General Theory of Non-equilibrium Dynamics of Lipid-protein Fluid Membranes
We present a general and systematic theory of non-equilibrium dynamics of
multi-component fluid membranes, in general, and membranes containing
transmembrane proteins, in particular. Developed based on a minimal number of
principles of statistical physics and designed to be a meso/macroscopic-scale
effective description, the theory is formulated in terms of a set of equations
of hydrodynamics and linear constitutive relations. As a particular emphasis of
the theory, the equations and the constitutive relations address both the
thermodynamic and the hydrodynamic consequences of the unconventional material
characteristics of lipid-protein membranes and contain proposals as well as
predictions which have not yet been made in already existed work on membrane
hydrodynamics and which may have experimental relevance. The framework
structure of the theory makes possible its applications to a range of
non-equilibrium phenomena in a range of membrane systems, as discussions in the
paper of a few limit cases demonstrate.Comment: 22 pages, 2 figures, minor changes and addition
Giant vesicles at the prolate-oblate transition: A macroscopic bistable system
Giant phospholipid vesicles are shown to exhibit thermally activated
transitions between a prolate and an oblate shape on a time scale of several
seconds. From the fluctuating contour of such a vesicle we extract ellipticity
as an effective reaction coordinate whose temporal probability distribution is
bimodal. We then reconstruct the effective potential from which we derive an
activation energy of the order of in agreement with theoretical
calculations. The dynamics of this transition is well described within a
Kramers model of overdamped diffusion in a bistable potential. Thus, this
system can serve as a model for macroscopic bistability.Comment: 10 pages, LaTeX, epsfig, 4 eps figures included, to appear in
Europhys. Let
Iterative Classroom Teaching
We consider the machine teaching problem in a classroom-like setting wherein
the teacher has to deliver the same examples to a diverse group of students.
Their diversity stems from differences in their initial internal states as well
as their learning rates. We prove that a teacher with full knowledge about the
learning dynamics of the students can teach a target concept to the entire
classroom using O(min{d,N} log(1/eps)) examples, where d is the ambient
dimension of the problem, N is the number of learners, and eps is the accuracy
parameter. We show the robustness of our teaching strategy when the teacher has
limited knowledge of the learners' internal dynamics as provided by a noisy
oracle. Further, we study the trade-off between the learners' workload and the
teacher's cost in teaching the target concept. Our experiments validate our
theoretical results and suggest that appropriately partitioning the classroom
into homogenous groups provides a balance between these two objectives.Comment: AAAI'19 (extended version
Les carences nutritionnelles dans les PVD
Les caractéristiques anthropométriques (poids, taille) de 373 enfants congolais d'âge préscolaire issus de milieux favorisés de Brazzaville ont été relevées. La distribution des critères anthropométriques est très voisine de celle de la population de référence NCHS qu'il s'agisse du poids ou de la taille en fonction de l'âge. Les retards de taille et les maigreurs sont des phénomènes peu fréquents et d'apparition brève contrairement à ce qui est observé dans d'autres échantillons représentatifs de populations urbaines et rurales. Ainsi, les différences ethniques ou raciales s'avèrent négligeables par rapport à celles liées à l'environnement. (Résumé d'auteur
On the evaluation of the conversational speech quality in telecommunications
International audienceIn this paper we propose an objective method to assess speech quality in the conversational context by taking into account the talking and listening speech qualities and the impact of delay. This approach is applied to the results of four subjective tests on the effects of echo, delay, packet loss and noise. The dataset is divided into training and validation sets. For the training set, a multiple linear regression is applied to determine a relationship between conversational, talking and listening speech qualities and the delay value. The multiple linear regression leads to an accurate estimation of the conversational scores with high correlation and low error between subjective and estimated scores, both on the training and validation sets. In addition, a validation is performed on the data of a subjective test found in the literature which confirms the reliability of the regression. The relationship is then applied to an objective level by replacing talking and listening subjective scores with talking and listening objective scores provided by existing objective models, fed by speech signals recorded during the subjective tests. The conversational model achieves high perfor- mance as revealed by comparison with the test results and with the existing standard methodology “E-model”, presented in the ITU-T (International Telecommunication Union) Recommendation G.107
Detecting information flow direction in multivariate linear and nonlinear models
International audienceIn this paper we present an approach to analyze the direction of information flow between time series involving bidirectional relations. The intuitive idea comes from a first study dedicated to the so-called phase slope index, which is a measure originally developed to detect unidirectional relations and is based on the complex coherence function. In order to detect bidirectional flows, we propose two new causality indices supplying the previous index with two other functions, the directed coherence function and the directed transfer function. Moreover, to cope with the inability of the approaches based on coherence (ordinary or directed) or on directed transfer function to distinguish between direct and indirect relations, we propose another causality index based on the partial directed coherence to identify only direct relations. Experimental results show that some challenges have promising solutions through the use of this new indicator dealing with both linear and nonlinear multivariate models
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