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3D simulation of the leaching of cement-based materials in order to compare different leaching tests G. Aouad et al. Leaching of cement-based materials is a complex process that depends on both the material intrinsic properties and the leaching test. The microstructure and cement-type of the material are typical examples of the former whereas the later consist of solution pH and composition, solution renewal rate and the liquid/solid volume ratio. As most of the tests are not normalized, this leads to a diversity of results in terms of alteration layer thicknesses and leaching kinetics. As a consequence, it is often difficult to compare and transpose experimental data from one experience to the other. 1D reactive transport modeling has proven to be adequate to simulate the coupling between diffusion, dissolution / precipitation and sorption processes that take place during leaching. The aim of this study is to demonstrate the usefulness of 3D reactive transport modeling to accurately simulate the features of the leaching device features, which is essential to compare results obtained by different leaching tests. Such simulations also enable to assess the mutual interaction between samples if the device contains several of them. Additionally, these simulations represent an interesting numerical tool in order to design new or complementary leaching tests.

Damage induced to DNA by low-energy (0-30 eV) electrons under vacuum and atmospheric conditions. Emilie Brun et al. In this study, we show that it is possible to obtain data on DNA damage induced by low-energy (0-30 eV) electrons under atmospheric conditions. Five monolayer films of plasmid DNA (3197 base pairs) deposited on glass and gold substrates are irradiated with 1.5 keV X-rays in ultrahigh vacuum and under atmospheric conditions. The total damage is analyzed by agarose gel electrophoresis. The damage produced on the glass substrate is attributed to energy absorption from X-rays, whereas that produced on the gold substrate arises from energy absorption from both the X-ray beam and secondary electrons emitted from the gold surface. By analysis of the energy of these secondary electrons, 96% are found to have energies below 30 eV with a distribution peaking at 1.4 eV. The differences in damage yields recorded with the gold and glass substrates is therefore essentially attributed to the interaction of low-energy electrons with DNA under vacuum and hydrated conditions. From these results, the G values for low-energy electrons are determined to be four and six strand breaks per 100 eV, respectively.

Isolement, étude structurale et propriétés antibiotiques et antifongiques d'un composant polysaccharidique de la diatomée marine Cheatoceros Lauderi (Ralfs CC) D. Pesando et al. The marine diatom Chaetoceros lauderi produces a high molecular weight ionic polysaccharide which exhibits a significant antibiotic activity against staphylococcus species acid pathogenic fungi. Acidic hydrolysis followed by GC-MS identification of the corresponding alditol acetates leads to a basic structural compotion comprising arabinose, xylose, galactorse, mannose and glucose in the ration 12:21:15:25:5. The presence of uronic and sulfate residues in the ratio 3:2 is suspected from the conductimetric titration curve using sodium hydroxyde.

Stochastic target problems with controlled loss in jump diffusion models Ludovic Moreau In this paper, we consider a mixed diffusion version of the stochastic target problem introduced by Bouchard et al. (2009). This consists in finding the minimum initial value of a controlled process which guarantees to reach a controlled stochastic target with a given lovel of expected loss. As in Bouchard et al. (2009), it can be converted into a standard stochastic target problem, as already studied by Soner and Touzi (2002) or Bouchard (2002) for the mixed diffusion case, by increasing both the state space and the dimension of the control. In our mixed-diffusion setting, the main difficulty comes from the presence of jumps, which leads to the introduction of a new kind of controls that take values in an unbounded set of measurable maps. This has non trivial impacts on the formulation and derivation of the associated partial differential equations.

« La crise financière et l'application des accords de Bâle : est ce le meilleur remède ? ». Hamza Fekir Afin de s'adapter à la libéralisation de la sphère financière entamée dans les années 80, marquée notamment par la fin de l'encadrement de crédit, la disparition des différentes formes de protection de l'Etat dont bénéficiaient les banques, et la privatisation de la quasi-totalité des établissements en Europe, la réglementation bancaire a évolué vers une approche prudentielle, perçue comme le seul mode de régulation n'entrant pas en contradiction avec les règles du marché. La réglementation bancaire actuelle ‘Bâle II' s'appuie sur la supervision, la discipline du marché et les ratios prudentiels, en particulier les ratios des fonds propres minimaux. La crise financière dénommée de ‘subprime' qu'a traversé le monde durant ces dernières années a poussé plusieurs économistes à se demander si cette réglementation prudentielle est toujours d'actualité, et surtout pourquoi n'a pas-t-elle permis de prévoir et d'éviter la crise actuelle. L'objet donc, de cet article est de présenter l'architecture du nouvel accord de Bâle qui se base sur trois piliers se consolidant mutuellement, et surtout d'expliquer quel rôle a-t-il pu jouer dans cette crise financière.

Analysis of the sensitivity to discrete dividends : A new approach for pricing vanillas Arnaud Gocsei et al. The incorporation of a dividend yield in the classical option pricing model of Black- Scholes results in a minor modification of the Black-Scholes formula, since the lognormal dynamic of the underlying asset is preserved. However, market makers prefer to work with cash dividends with fixed value instead of a dividend yield. Since there is no closed-form solution for the price of a European Call in this case, many methods have been proposed in the literature to approximate it. Here, we present a new approach. We derive an exact analytic formula for the sensitivity to dividends of an European option. We use this result to elaborate a proxy which possesses the same Taylor expansion around 0 with respect to the dividends as the exact price. The obtained approximation is very fast to compute (the same complexity than the usual Black-Scholes formula) and numerical tests show the extreme accuracy of the method for all practical cases.

Matrix-based Implicit Representations of Rational Algebraic Curves and Applications Laurent Busé et al. Given a parameterization of an algebraic rational curve in a projective space of arbitrary dimension, we introduce and study a new implicit representation of this curve which consists in the locus where the rank of a single matrix drops. Then, we illustrate the advantages of this representation by addressing several important problems of Computer Aided Geometric Design: The point-on-curve and inversion problems, the computation of singularities and the intersection problem between two rational curves.

Modeling and Analysis of Stage Machinery Control Systems by Timed Colored Petri Nets Hehua Zhang et al. This paper presents an approach and successful experience of applying timed colored Petri nets on modeling and analyzing a stage machinery control system. The programmable logic controllers (PLCs) based system is modeled with timing constraints. The compositionality is incorporated in the modeling process of the entire design. The PLC synchronization problem with the interactions of environment is analyzed by the state space analysis method. The case studies demonstrate the effectiveness of the approach.

Grimage: markerless 3D interactions Jérémie Allard et al. Grimage glues multi-camera 3D modeling, physical simulation and parallel execution for a new immersive experience. Put your hands or any object into the interaction space. It is instantaneously mod- eled in 3D and injected into a virtual world populated with solid and soft objects. Push them, catch them and squeeze them.

Approximate roots of a valuation and the Pierce-Birkhoff Conjecture François Lucas et al. This paper is a step in our program for proving the Piece-Birkhoff Conjecture for regular rings of any dimension (this would contain, in particular, the classical Pierce-Birkhoff conjecture which deals with polynomial rings over a real closed field). We first recall the Connectedness and the Definable Connectedness conjectures, both of which imply the Pierce - Birkhoff conjecture. Then we introduce the notion of a system of approximate roots of a valuation v on a ring A (that is, a collection Q of elements of A such that every v-ideal is generated by products of elements of Q). We use approximate roots to give explicit formulae for sets in the real spectrum of A which we strongly believe to satisfy the conclusion of the Definable Connectedness conjecture. We prove this claim in the special case of dimension 2. This proves the Pierce-Birkhoff conjecture for arbitrary regular 2-dimensional rings.

Singular metrics on the two-sphere in space mechanics Bernard Bonnard et al. Riemannian metrics on the sphere of revolution with an equatorial singularity are introduced so as to study dynamics arising in space mechanics and two-body control. A homotopy from the round metric on the sphere is defined which gives evidence of classification by the order of singularity for such metrics. Symmetry, integrability and quasi-homogeneity properties near the singularity unveil the main features of geodesics and allow to compute asymptotics, in connection with optimality issues. This question is fully addressed in the end of the paper where cut and conjugate loci are analyzed, providing examples of bifurcation and collapsing.

MACAULAY INVERSE SYSTEMS REVISITED Jean-François Pommaret Since its original publication in 1916 under the title "The Algebraic Theory of Modular Systems", the book by F. S. Macaulay has attracted a lot of scientists with a view towards pure mathematics (D. Eisenbud,...) or applications to control theory (U. Oberst,...).However, a carefull examination of the quotations clearly shows that people have hardly been looking at the last chapter dealing with the so-called "inverse systems", unless in very particular situations. The purpose of this paper is to provide for the first time the full explanation of this chapter within the framework of the formal theory of systems of partial differential equations (Spencer operator on sections, involution,...) and its algebraic counterpart now called "algebraic analysis" (commutative and homological algebra, differential modules,...). Many explicit examples are fully treated and hints are given towards the way to work out computer algebra packages.

Phase-space description of the magneto-optical trap Rudy Romain et al. An exhaustive kinetic model for the atoms in a 1D Magneto-Optical Trap is derived, without any approximations. It is shown that the atomic density is described by a Vlasov-Fokker-Planck equation, coupled with two simple differential equations describing the trap beam propagation. The analogy of such a system with plasmas is discussed. This set of equations is then simplified through some approximations, and it is shown that corrective terms have to be added to the models usually used in this context.

Evidence from the asteroid belt for a violent past evolution of Jupiter's orbit Alessandro Morbidelli et al. We use the current orbital structure of large (>50km) asteroids in the main asteroid belt to constrain the evolution of the giant planets when they migrated from their primordial orbits to their current ones. Minton & Malhotra (2009) showed that the orbital distribution of large asteroids in the main belt can be reproduced by an exponentially-decaying migration of the giant planets on a time scale of tau ~ 0.5My. However, self-consistent numerical simulations show that the planetesimal-driven migration of the giant planets is inconsistent with an exponential change in their semi major axes on such a short time scale (Hahn & Malhotra, 1999). In fact, the typical time scale is tau > 5My. When giant planet migration on this time scale is applied to the asteroid belt, the resulting orbital distribution is incompatible with the observed one. However, the planet migration can be significantly sped up by planet-planet encounters. Consider an evolution where both Jupiter and Saturn have close encounters with a Neptune-mass planet (presumably Uranus or Neptune themselves) and where this third planet, after being scattered inwards by Saturn, is scattered outwards by Jupiter. This scenario leads to a very rapid increase in the orbital separation between Jupiter and Saturn that we show here to have only mild effects on the structure of asteroid belt. This type of evolution is called a jumping-Jupiter case. Our results suggest that the total mass and dynamical excitation of the asteroid belt before migration were comparable to those currently observed. Moreover, they imply that, before migration, the orbits of Jupiter and Saturn were much less eccentric than the current ones.

The second critical point for the Perfect Bose gas in quasi-one-dimensional traps Mathieu Beau et al. We present a new model of quasi-one-dimensional trap with some unknown physical predictions about a second transition, including about a change in fractions of condensed coherence lengths due to the existence of a second critical temperature Tm < Tc. If this physical model is acceptable, we want to challenge experimental physicists in this regard.

Shrinkage of microaggregates in Brazilian Latosols during drying: significance of the clay content, mineralogy and hydric stress history Adriana Reatto-Braga et al. Latosols are characterized by a poor differentiation of the horizons, a weak macrostructure and a strong submillimetric granular structure resulting in microaggregates 50 to 300 µm in size. The shrinkage properties of these microaggregates that are generally considered as very weak or absent are still under discussion. The objective of our study is the analyze the shrinkage properties of microaggregates in diagnostic Bw horizons collected in a set of Latosols varying in their particle size distribution and mineralogical composition according to their location in a regional toposequence across the Brazilian Central Plateau. We measured the water retention properties at 300 and 1500 kPa by using the centrifugation method. The morphology and size of the elementary particles was studied by using transmission electron microscopy and determining the specific surface area (SSA) with the BET method. We determined also the pore size distribution of the microaggregates by combining mercury intrusion and nitrogen desorption isotherm. Our results showed that the microaggregates of the Latosols studied are not rigid but shrink during drying. The pore volume of the microaggregates at –300 and –1500 kPa as well as the pore volume of the dried microaggregates are closely related to the clay content. The SSA is also closely related to the clay content. Consequently, the mineralogy of the <2 µm would play at the most a marginal role in the properties studied. Finally, our results showed that the shrinkage of the microaggregates between –300 kPa and the shrinkage limit and between –1500 kPa and the shrinkage limit varies with the location of the Latosols in the Landscape. Thus, the microaggregates of the Latosols located on the SAS shrink less than those of the Latosols located on the VS. This difference might be related to a difference of hydric stress history of the Latosols.

3D simulation of the leaching of cement-based materials in order to compare different leaching tests G. Aouad et al. Leaching of cement-based materials is a complex process that depends on both the material intrinsic properties and the leaching test. The microstructure and cement-type of the material are typical examples of the former whereas the later consist of solution pH and composition, solution renewal rate and the liquid/solid volume ratio. As most of the tests are not normalized, this leads to a diversity of results in terms of alteration layer thicknesses and leaching kinetics. As a consequence, it is often difficult to compare and transpose experimental data from one experience to the other. 1D reactive transport modeling has proven to be adequate to simulate the coupling between diffusion, dissolution / precipitation and sorption processes that take place during leaching. The aim of this study is to demonstrate the usefulness of 3D reactive transport modeling to accurately simulate the features of the leaching device features, which is essential to compare results obtained by different leaching tests. Such simulations also enable to assess the mutual interaction between samples if the device contains several of them. Additionally, these simulations represent an interesting numerical tool in order to design new or complementary leaching tests.

Mechanical properties of the elemental nanocomponents of nacre structure Philippe Stempflé et al. Sheet nacre is a nanocomposite with a multiscale structure displaying a lamellar “bricks and mortar” microarchitecture. In this latter, the brick refer to aragonite platelets and the mortar to a soft organic biopolymer. However, it appears that each brick is also a nanocomposite constituted as CaCO3 nanoparticles reinforced organic composite material. What is the role of this “intracrystalline” organic phase in the deformation of platelet? How does this nanostructure control the mechanical behaviour of sheet nacre at the macroscale? To answer these questions, the mechanical properties of each nanocomponents are successively investigated and computed using spherical and sharp nanoindentation tests combined with a structural model of the organomineral platelets built from AFM investigations.

Structure of Optimal Transport Networks Subject to a Global Constraint Marc Durand The structure of pipe networks minimizing the total energy dissipation rate is studied analytically. Among all the possible pipe networks that can be built with a given total pipe volume (or pipe lateral surface area), the network which minimizes the dissipation rate is shown to be loopless. Furthermore, such an optimal network is shown to contain at most N-2 nodes in addition to the N sources plus sinks that it connects. These results are valid whether the possible locations for the additional nodes are chosen freely or from a set of nodes (such as points of a grid). Applications of these results to various physical situations and to the efficient computation of optimal pipe networks are also discussed.

Observation of nonlinear dispersion relation and spatial statistics of wave turbulence on the surface of a fluid Eric Herbert et al. We report experiments on gravity-capillary wave turbulence on the surface of a fluid. The wave amplitudes are measured simultaneously in time and space using an optical method. The full space-time power spectrum shows that the wave energy is localized on several branches in the wave-vector-frequency space. The number of branches depend on the power injected within the waves. The measurement of the nonlinear dispersion relation is found to be well described by a law suggesting that the energy transfer mechanisms involved in wave turbulence are not only restricted to purely resonant interaction between nonlinear waves. The power-law scaling of the spatial spectrum and the probability distribution of the wave amplitudes at a given wave number are also measured and compared to the theoretical predictions.

Nonlinear waves in Newton's cradle and the discrete p-Schroedinger equation Guillaume James We study nonlinear waves in Newton's cradle, a classical mechanical system consisting of a chain of beads attached to linear pendula and interacting nonlinearly via Hertz's contact forces. We formally derive a spatially discrete modulation equation, for small amplitude nonlinear waves consisting of slow modulations of time-periodic linear oscillations. The fully-nonlinear and unilateral interactions between beads yield a nonstandard modulation equation that we call the discrete p-Schroedinger (DpS) equation. It consists of a spatial discretization of a generalized Schroedinger equation with p-Laplacian, with fractional p>2 depending on the exponent of Hertz's contact force. We show that the DpS equation admits explicit periodic travelling wave solutions, and numerically find a plethora of standing wave solutions given by the orbits of a discrete map, in particular spatially localized breather solutions. Using a modified Lyapunov-Schmidt technique, we prove the existence of exact periodic travelling waves in the chain of beads, close to the small amplitude modulated waves given by the DpS equation. Using numerical simulations, we show that the DpS equation captures several other important features of the dynamics in the weakly nonlinear regime, namely modulational instabilities, the existence of static and travelling breathers, and repulsive or attractive interactions of these localized structures.

A Lexicon of French Quotation Verbs for Automatic Quotation Extraction Benoît Sagot et al. Quotation extraction is an important information extraction task, especially when dealing with news wires. Quotations can be found in various configurations. In this paper, we focus on direct quotations introduced by a parenthetical clause, headed by a “quotation verb”. Our study is based on a large French news wire corpus from the Agence France-Presse. We introduce and motivate an analysis at the discursive level of such quotations, which differs from the syntactic analyses generally proposed. We show how we enriched the Lefff syntactic lexicon so that it provides an account for quotation verbs heading a quotation parenthetical, especially those extracted from a news wire corpus. We also sketch how these lexical entries can be extended to the discursive level in order to model quotations introduced in a parenthetical clause in a complete way.

Améliorer un lexique syntaxique à l'aide des tables du lexique-grammaire — Constructions impersonnelles et expressions verbales figées Benoît Sagot et al. We intend to develop a large-coverage morphological and syntactic lexicon for French which can be directly used in Natural Langage Processing (NLP) applications, in particular in those involving deep parsing, regardless of the underlying grammatical framework. This lexicon, named Lefff (Lexique des Formes Fléchies du Français — Lexicon of French inFlected Forms), has been under development since 2004. At the beginning, this lexicon contained only verbal morphological information, mostly automatically induced from corpora. It now covers all parts of speech, and is progressively enriched with syntactic information. In this paper, we show how we used the lexicon-grammar tables, whose development has been initiated by M. Gross, to enrich the Lefff. These tables are a valuable starting point. However, it is necessary to achieve both a linguistic and formal modeling work, in order to exploit their content in a NLP lexicon such as the Lefff. We illustrate this approach on two kinds of non-standard verbal and adjectival entries : impersonal structures and verbal idiomatic expressions. --- Nous avons le projet de développer un lexique morphologique et syntaxique du français à large couverture qui soit directement utilisable dans des applications de Traitement Automatique du Langage (TAL), en particulier celles nécessitant une analyse syntaxique profonde, et ce, quel que soit le cadre théorique utilisé. Ce lexique, baptisé Lefff (Lexique des Formes Fléchies du Français), est en cours de développement depuis 2004. Au départ, ce lexique ne comportait que des informations morphologiques verbales, principalement induites automatiquement à partir de corpus. Il couvre maintenant toutes les catégories, et est progressivement enrichi d'informations syntaxiques. Nous montrons ici comment nous l'avons enrichi à partir des tables du lexique-grammaire, initialement développées autour de M. Gross. Celles-ci constituent un point de départ d'une valeur inestimable. Il est néanmoins nécessaire de procéder à un double travail de linguistique et de modélisation, afin d'exploiter leur contenu dans un lexique TAL tel que le Lefff. Nous illustrons cette approche sur deux types d'entrées verbales et adjectivales non standard : les constructions impersonnelles et les expressions verbales figées.

Constructions pronominales dans Dicovalence et le lexique-grammaire – Intégration dans le Lefff Laurence Danlos et al. Dans le but de construire un lexique morpho-syntaxique du français à large couverture et utilisable dans les applications de Traitement Automatique des Langues (TAL), et dans le prolongement de travaux déjà effectués dans cette direction, en particulier sur les constructions impersonnelles, nous nous intéressons ici aux constructions pronominales. Notre objectif est triple : (1) réaliser une étude comparative du traitement des constructions pronominales dans le lexique-grammaire (Gross, 1975; Leclère, 2002) et dans Dicovalence (Van den Eynde & Mertens, 2006), (2) proposer une formalisation des résultats de ces travaux qui soit adaptée au TAL, dans le cadre du formalisme utilisé par le Lefff 3, dernière version du Lefff décrite brièvement ci-dessous, (3) fusionner dans le Lefff les informations lexicales présentes du lexique-grammaire et de Dicovalence concernant les constructions pronominales.

Shrinkage of microaggregates in Brazilian Latosols during drying: significance of the clay content, mineralogy and hydric stress history Adriana Reatto-Braga et al. Latosols are characterized by a poor differentiation of the horizons, a weak macrostructure and a strong submillimetric granular structure resulting in microaggregates 50 to 300 µm in size. The shrinkage properties of these microaggregates that are generally considered as very weak or absent are still under discussion. The objective of our study is the analyze the shrinkage properties of microaggregates in diagnostic Bw horizons collected in a set of Latosols varying in their particle size distribution and mineralogical composition according to their location in a regional toposequence across the Brazilian Central Plateau. We measured the water retention properties at 300 and 1500 kPa by using the centrifugation method. The morphology and size of the elementary particles was studied by using transmission electron microscopy and determining the specific surface area (SSA) with the BET method. We determined also the pore size distribution of the microaggregates by combining mercury intrusion and nitrogen desorption isotherm. Our results showed that the microaggregates of the Latosols studied are not rigid but shrink during drying. The pore volume of the microaggregates at –300 and –1500 kPa as well as the pore volume of the dried microaggregates are closely related to the clay content. The SSA is also closely related to the clay content. Consequently, the mineralogy of the <2 µm would play at the most a marginal role in the properties studied. Finally, our results showed that the shrinkage of the microaggregates between –300 kPa and the shrinkage limit and between –1500 kPa and the shrinkage limit varies with the location of the Latosols in the Landscape. Thus, the microaggregates of the Latosols located on the SAS shrink less than those of the Latosols located on the VS. This difference might be related to a difference of hydric stress history of the Latosols.

3D simulation of the leaching of cement-based materials in order to compare different leaching tests G. Aouad et al. Leaching of cement-based materials is a complex process that depends on both the material intrinsic properties and the leaching test. The microstructure and cement-type of the material are typical examples of the former whereas the later consist of solution pH and composition, solution renewal rate and the liquid/solid volume ratio. As most of the tests are not normalized, this leads to a diversity of results in terms of alteration layer thicknesses and leaching kinetics. As a consequence, it is often difficult to compare and transpose experimental data from one experience to the other. 1D reactive transport modeling has proven to be adequate to simulate the coupling between diffusion, dissolution / precipitation and sorption processes that take place during leaching. The aim of this study is to demonstrate the usefulness of 3D reactive transport modeling to accurately simulate the features of the leaching device features, which is essential to compare results obtained by different leaching tests. Such simulations also enable to assess the mutual interaction between samples if the device contains several of them. Additionally, these simulations represent an interesting numerical tool in order to design new or complementary leaching tests.

Mechanical properties of the elemental nanocomponents of nacre structure Philippe Stempflé et al. Sheet nacre is a nanocomposite with a multiscale structure displaying a lamellar “bricks and mortar” microarchitecture. In this latter, the brick refer to aragonite platelets and the mortar to a soft organic biopolymer. However, it appears that each brick is also a nanocomposite constituted as CaCO3 nanoparticles reinforced organic composite material. What is the role of this “intracrystalline” organic phase in the deformation of platelet? How does this nanostructure control the mechanical behaviour of sheet nacre at the macroscale? To answer these questions, the mechanical properties of each nanocomponents are successively investigated and computed using spherical and sharp nanoindentation tests combined with a structural model of the organomineral platelets built from AFM investigations.

Les non-linguistes font-ils de la linguistique ? Marie-Anne Paveau Cet article traite la question de la folk linguistique par le biais des activités des non-linguistes. On examine d'abord la figure du folk linguiste, en présentant une typologie en régime scalaire et non binaire, du linguiste amateur scripteur de manuels au comique producteur de jeux de mots sur scène, en passant par les écrivains, juristes, et autes locuteurs concernés par les questions langagières. Puis on revient sur la question de la validité des savoirs folk, en faisant une revue des positions possibles en philosophie des sciences (éliminativisme de P. Churchland et réalisme doux de D. Dennett). On propose une troisième posture dite “intégrationniste” : les savoirs folks sont des savoirs à part entière, et ils doivent de ce fait être intégrés à la linguistique qui, par ailleurs, ne repose parfois que sur les intuitions des linguistes professionnels.

Une énonciation sans communication : les tatouages scripturaux Marie-Anne Paveau Scriptural tattoos let us think that the human body is a support for discourse production in the traditional way of indexical communication, meaning the existence of two speakers, a linguistic form and its interpretation. In fact, tattooed enunciation is a very peculiar one and proposes [allows] strong arguments to claim the noncommunicative enunciation thesis : speakers are disconnected and even absent from interaction ; they are also most of the time anonymous ; texts are sometimes hidden and therefore set unspeakable sentences up. Consequently the standard enunciation theory must be revisited and one has to propound other hypothesis as biosubjectivity and bioreferentialism.

Financiarisation de la ville et développement urbain durable : le cas des sociétés foncières cotées en France Cyril Boisnier La question centrale de cette communication est de réfléchir sur la manière dont deux mouvements, a priori antinomiques de par leurs objectifs, la financiarisation de l'immobilier tertiaire à la recherche d'un profit immédiat, d'une part, le DUD en accord avec une rentabilité de long terme, d'autre part, sont « négociés » (THEURILLAT et al., 2009) dans la ville d'aujourd'hui. L'étude de cette probable divergence d'objectifs en termes de temporalité et de valeurs demeure un enjeu de société qui préoccupe le monde académique. Au « terrorisme » du court terme, qui s'accentue, devra se substituer une vision à long terme partagée par toutes les parties prenantes (BIPE, 2009).

Étude par co-simulation du principe d'une Interconnexion RF associée à un multiplexage CDMA Yves Constant Mombo Boussougou et al. Dans ce papier nous développons de nouvelles interconnexions, de type radiofréquences, pour remplacer les interconnexions classiques de circuits numériques. A l'aide d'outils de co simulation, nous avons modélisé ce principe d'interconnexion associé à un multiplexage numérique de type CDMA et une modulation d'amplitude. A titre d'exemple, nous présentons la réponse fréquentielle d'un canal radiofréquence ainsi que les différents signaux observables le long de la chaine. Cette modélisation pourra par la suite être utilisée afin de développer le concept d'interconnexion radiofréquence.

Study of Proximity-Coupling: Application to new RF-Interconnects Yves Constant Mombo Boussougou et al. The new concept of RF Interconnect presented in this paper is aimed at replacing conventional interconnections in digital circuits. The study was, thus, focused on the transmission channel composed of contactless transitions. After a brief recall of the theory, an RF interconnection was modeled through use of multiplexing digital CDMA and amplitude modulation and characterized by using a co-simulation tool. The frequency response of a radiofrequency channel and the signal forms observed along the transmission system are presented to highlight the capabilities of this RF interconnect.

Modélisation et optimisation de dispositifs non-linéaires d'amortissement de structures par systèmes piézoélectriques commutés Julien Ducarne Afin de réduire les vibrations d'une structure, on utilise des éléments piézoélectriques connectés à des circuits électriques passifs. L'objectif est de se rapprocher de l'efficacité du contrôle actif sans en supporter la complexité et la consommation. On considère d'abord l'association d'une résistance (qui a un effet similaire à un amortissement visqueux) et éventuellement d'une inductance (permettant de réaliser un oscillateur accordé) aux éléments piézoélectriques. Ces systèmes ont des propriétés intéressantes, mais sont peu efficaces à moins d'un accord très précis de l'inductance. Afin d'obtenir des performances élevées sans accord précis, on étudie un circuit à commutation, qui se ferme et s'ouvre à des instants bien précis. L'effet de la charge, qui freine la structure, s'apparente à un frottement sec. En synchronisant les commutations sur les vibrations, le système est auto-adaptatif et peut être auto-alimenté. Les fortes non-linéarités entraînent une excitation haute fréquence de la structure qui peut rendre la synchronisation problématique. Deux modèles électromécaniques (analytique et éléments finis) réduits sont proposés, permettant de décrire la dynamique du système complet de manière précise et de mettre en valeur le couplage entre un mode de vibration et le circuit électrique. Ce couplage est déterminant pour la réduction de vibrations. Une étude de l'influence de divers paramètres permet d'optimiser les éléments piézoélectriques, les circuits, et les instants de commutation. Ces résultats sont vérifiés expérimentalement. On constate un bon accord avec la théorie ; la difficulté de synchroniser correctement la commutation est aussi constatée.

Gender and genotype modulation of the association between lipid levels and depressive symptomatology in community-dwelling elderly (the ESPRIT study). Marie-Laure Ancelin et al. BACKGROUND: Lipids appear to mediate depressive vulnerability in the elderly; however, sex differences and genetic vulnerability have not been taken into account in previous prospective studies. METHODS: Depression was assessed in a population of 1040 women and 752 men aged 65 years and older at baseline and after 7-year follow-up. Clinical level of depression (DEP) was defined as having either a score of 16 or higher on the Centre for Epidemiology Studies Depression scale or a diagnosis of current major depression on the Mini-International Neuropsychiatric Interview. Lipid levels, apolipoprotein E, and serotonin transporter linked promoter region (5-serotonin transporter gene linked promoter region) genotypes were evaluated at baseline. RESULTS: Multivariate analyses adjusted by sociodemographic and behavioral variables, measures of physical health including ischemic pathologies, and genetic vulnerability indicated gender-specific associations between dyslipidemia and DEP, independent of the use of lipid-lowering agents or apolipoprotein E status. Men with low low-density lipoprotein cholesterol levels had twice the risk of prevalent and incident DEP, whereas in women low high-density lipoprotein cholesterol levels were found to be significantly associated with increased prevalent DEP (odds ratio = 1.5) only. A significant interaction was observed between low low-density lipoprotein-cholesterol and 5-serotonin transporter gene linked promoter region genotype, men with s/s or s/l genotype being at increased risk of DEP (odds ratio = 6.0 and 2.7, respectively). No significant gene-environment interaction was observed for women. CONCLUSIONS: DEP is associated with higher atherogenic risk in women (low high-density lipoprotein cholesterol), whereas the reverse is observed in men (low low-density lipoprotein cholesterol). Late-life depression may have a complex gender-specific etiology involving genetic vulnerability in men.

Etude des interfaces sang/cerveau dans la région tubérale de l'hypothalamus médiobasal: rôle des tanycytes de l'éminence médiane. Amandine Mullier L'hypothalamus joue un rôle critique dans la régulation des systèmes physiologiques et de l'homéostasie. Il relaie au niveau central les signaux ou hormones sécrétées en périphérie. L'intégration de ces signaux s'effectue au niveau des interfaces sang/cerveau. Trois grandes interfaces sang/cerveau sont décrites au niveau central : la barrière hémato-encéphalique, les plexus choroïdes et les organes circumventriculaires. Alors que les deux premières sont bien caractérisées, les organes circumventriculaires sont mal connus. La région tubérale de l'hypothalamus médiobasal est une région cérébrale organisée autour du troisième ventricule. Elle a la particularité de contenir à la fois des noyaux hypothalamiques impliqués dans la régulation de grandes fonctions neuroendocrines et l'éminence médiane. L'éminence médiane est un organe circumventriculaire caractérisé par la présence de capillaires fenêtrés permettant la diffusion des molécules circulantes dans le parenchyme cérébral. Cependant, l'éminence médiane est également constituée de cellules épendymogliales particulières appelées tanycytes et dont les fonctions sont encore mal connues. Une des hypothèses est que les tanycytes formeraient une interface sang/cerveau impliquée dans la régulation des échanges entre le sang porte et le liquide céphalorachidien. En accord avec cette hypothèse, des expériences d'immunohistochimie entreprises chez la souris adulte nous ont indiqué que les tanycytes expriment des protéines de jonctions serrées et que cette expression et différente selon leur localisation. En effet, les tanycytes ventraux de l'éminence médiane expriment l'occludine, zonula-occludens-1, la claudine 5 et la claudine 1. De façon intéressante, ces protéines sont organisées en forme de nids d'abeilles autour des corps cellulaires des tanycytes. A l'inverse, les tanycytes dorsaux localisés sur les parois latérales du ventricule expriment l'occludine, zonula occludens-1 et la claudine 5 mais ces protéines ne sont pas organisées en nids d'abeille. Parallèlement, des injections de bleu d'Evans ont permis de montrer que seuls les tanycytes ventraux possèdent des jonctions serrées étanches qui restreignent les échanges entre le compartiment sanguin et le liquide céphalorachidien. En revanche, les tanycytes dorsaux sont perméables à la diffusion du bleu d'Evans indiquant ainsi que les échanges entre le liquide céphalorachidien et le noyau arqué hypothalamique ne sont pas restreints. Cette expression différentielle des protéines de jonctions serrées au niveau de la région tubérale de l'hypothalamus médiobasal est retrouvée également chez le rat adulte. De façon intéressante, des études plus poussées montrent que quelque soit le niveau antéropostérieur étudié, la présence de capillaires fenêtrés est toujours corrélée à la présence de tanycytes exprimant des protéines de jonctions serrées sous forme de nids d'abeilles et qui restreignent la communication entre le sang et le liquide céphalorachidien dans l'hypothalamus médiobasal. Ces résultats suggèrent fortement l'existence d'une intercommunication entre tanycytes et cellules endothéliales impliquée dans la mise en place du phénotype de barrière des tanycytes ventraux. Enfin des résultats préliminaires indiquent que les tanycytes expriment également des protéines de jonctions serrées chez l'Homme adulte. Notre travail montre que chez l'adulte, les tanycytes de l'éminence médiane constituent une interface sang/cerveau impliquée dans la régulation des échanges entre le sang porte et le liquide céphalorachidien. En parallèle, ces résultats apportent de nouvelles informations dans la compréhension des mécanismes régulant l'accès des hormones périphériques au noyau arqué hypothalamique et indiquent que l'éminence médiane pourrait être une voie de passage privilégiée vers ce noyau.

Intraoperative ultrasonography for the correction of brainshift based on the matching of hyperechogenic structures Pierrick Coupé et al. In this paper, a global approach based on 3D freehand ultrasound imaging is proposed to (a) correct the error of the neuronavigation system in image-patient registration and (b) compensate for the deformations of the cerebral structures occurring during a neurosurgical procedure. The rigid and non rigid multimodal registrations are achieved by matching the hyperechogenic structures of brain. The quantitative evaluation of the non rigid registration was performed within a framework based on synthetic deformation. Finally, experiments were carried out on real data sets of 4 patients with lesions such as cavernoma and low-grade glioma. Qualitative and quantitative results on the estimated error performed by neuronavigation system and the estimated brain deformations are given.

Regrouper les données textuelles et nommer les groupes à l'aide des classes recouvrantes Marian-Andrei Rizoiu et al. Organiser les données textuelles et en tirer du sens est un défi majeur aujourd'hui. Ainsi, lorsque l'on souhaite analyser un débat en ligne ou un forum de discussion, on voudrait pouvoir rapidement voir quels sont les principaux thèmes abordés et la manière dont la discussion se structure autour d'eux. Pour cela, et parce que un même texte peut être associé à plusieurs thèmes, nous proposons une méthode originale pour regrouper les données textuelles en autorisant les chevauchements et pour nommer chaque groupe de manière lisible. La contribution principale de cet article est une méthode globale qui permet de réaliser toute la chaîne, partant des données textuelles brutes jusqu'à la caractérisation des groupes à un niveau sémantique qui dépasse le simple ensemble de mots.

A fast, near efficient, randomized-trace based method for fitting stationary Gaussian spatial models to large noisy data sets in the case of a single range-parameter Didier A. Girard We consider the inference problem of fitting to noisy gridded observations, a isotropic zero-mean stationary Gaussian field model which belongs to the Mat\' ern family with known regularity index $\nu \geq 0$, or to the spherical family. For estimating the correlation range and the variance of the field, two simple estimating functions based on the so-called ``conditional Gibbs energy mean'' (CGEM) and the empirical variance (EV) were recently introduced. This article presents a rather extensive Monte Carlo simulation study for problems with around a thousand observations and settings including large, moderate, and even ``small'', correlation ranges. It empirically demonstrates that the statistical efficiency of CGEM-EV is quite satisfying provided the signal-to-noise ratio is strong enough or $\nu$ is not too large

Bernstein von Mises Theorems for Gaussian Regression with increasing number of regressors Dominique Bontemps This paper brings a contribution to the Bayesian theory of nonparametric and semiparametric estimation. We are interested in the asymptotic normality of the posterior distribution in Gaussian linear regression models when the number of regressors increases with the sample size. Two kinds of Bernstein-von Mises Theorems are obtained in this framework: nonparametric theorems for the parameter itself, and semiparametric theorems for functionals of the parameter. We apply them to the Gaussian sequence model and to the regression of functions in Sobolev and $C^{\alpha}$ classes, in which we get the minimax convergence rates. Adaptivity is reached for the Bayesian estimators of functionals in our applications.