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International audience, This study is devoted to the effective plastic flow surface of a bi-porous material saturated by a fluid. The material under consideration exhibits two populations of voids. The smaller voids are spherical voids whereas the larger ones are spheroidal and randomly oriented inside the material. These two populations of voids are subjected to internal pressures due to the presence of gases. Approximate models for the effective plastic flow surface of such a bi-porous saturated material have previously been proposed in (Vincent, P.-G., Monerie, Y., Suquet, P., 2009. International Journal of Solids and Structures 46, 480-506), where a three-scale homogenization procedure has been performed: first, smearing out all the small spherical bubbles using a Gurson-like matrix, and second, smearing out the intergranular ellipsoidal bubbles. Our objective here is to derive a simple analytical expression of the effective flow surface, starting from one of these previous models, obtained by generalizing the approach of (Gologanu, M., Leblond, J.B., Devaux, J., 1994. ASME Journal of Engineering Materials and Technology 116, 290-297) to compressible materials. The main contributions of the present paper are: (1) an expression for the average dilatation-rate in the matrix, (2) an approximation of the effective flow surface in the form of a Gurson-Tvergaard-Needleman criterion. The accuracy of this new model is assessed in a companion paper by comparison with full field numerical simulations.

International audience, This paper describes a simple technique for the fabrication of a gold microelectrode array with an integrated Ag/AgCl reference microelectrode based on polyimide (PI) which is a flexible and biocompatible thermoplastic substrate. The investigated fabrication technology was based on soft lithography which involved a combination of replica molding (RM) and patterning of self-assembled monolayers (SAMs), through microcontact printing (μCP). From a fabricated silicon microelectrode mold, an elastomeric stamp of the microelectrodes was replicated in polydimethylsiloxane (PDMS) and inked with octadecanethiol (ODT) for patterning of the gold surface. The non-patterned gold was then removed by selective chemical etching leaving very well defined gold microelectrodes with a high resolution. Finally, the integrated Ag/AgCl reference microelectrode was fabricated by silver electro-deposition onto the gold microelectrode. The developed biosensor was then tested for a medical application by immobilizing both monoclonal antibodies (mAb); anti-human interleukin-10 (IL-10) and anti-human tumor necrosis factor-alpha (TNF-α) onto different working electrodes. Functionalization of the gold microelectrodes was made with carboxyl diazonium through cyclic voltammetry (CV). The multiple detection of the corresponding cytokines was verified by fluorescence, whilst electrochemical impedance spectroscopy (EIS) analysis quantified a detectable IL-10 cytokine concentration from 1 to 15 pg/mL. This confirmed the biorecognition between the anti-human mAb (IL-10 and TNF-α) and of its corresponding cytokine. The obtained results show that the mAb's were efficiently immobilized and the proteins for human IL-10 were detectable at weak concentrations. The electrochemical measurements were applied on the manufactured gold microelectrodes for ∼9 h. This shows a high resistance of the microelectrodes for long-lasting measurements and, therefore, highlights the good adhesion of gold-PI. The results prese

International audience, This paper provides an overview of the AMPERE modeling comparison project with focus on the implications of near-term policies for the costs and attainability of long-term climate objectives. Nine modeling teams participated in the project to explore the consequences of global emissions following the proposed policy stringency of the national pledges from the Copenhagen Accord and Cancún Agreements to 2030. Specific features compared to earlier assessments are the explicit consideration of near-term 2030 emission targets as well as the systematic sensitivity analysis for the availability and potential of mitigation technologies. Our estimates show that a 2030 mitigation effort comparable to the pledges would result in a further "lock-in" of the energy system into fossil fuels and thus impede the required energy transformation to reach low greenhouse-gas stabilization levels (450 ppm CO2e). Major implications include significant increases in mitigation costs, increased risk that low stabilization targets become unattainable, and reduced chances of staying below the proposed temperature change target of 2 °C in case of overshoot. With respect to technologies, we find that following the pledge pathways to 2030 would narrow policy choices, and increases the risks that some currently optional technologies, such as carbon capture and storage (CCS) or the large-scale deployment of bioenergy, will become "a must" by 2030.

International audience, A construction tree is a set of shape generation processes commonly produced with CAD modelers during a design process of B-Rep objects. However, a construction tree does not bring all the desired properties in many configurations: dimension modifications, idealization processes, etc. Generating a non trivial set of generative processes, possibly forming a construction graph, can significantly improve the adequacy of some of these generative processes to meet user's application needs. This paper proposes to extract generative processes from a given B-rep shape as a high-level shape description. To evaluate the usefulness of this description, finite element analyses (FEA) and particularly idealizations are the applications selected to evaluate the adequacy of additive generative processes. Non trivial construction trees containing generic extrusion and revolution primitives behave like well established CSG trees. Advantageously, the proposed approach is primitive-based, which ensures that any generative process of the construction graph does preserve the realizability of the corresponding volume. In the context of FEA, connections between idealized primitives of a construction graph can be efficiently performed using their interfaces. Consequently, generative processes of a construction graph become a high-level object structure that can be tailored to idealizations of primitives and robust connections between them.

See paper for full list of authors - 8 pages plus author list (20 pages total), 2 figures, 3 tables, submitted to Physics Letters B, Using data recorded in 2011 with the ATLAS detector at the Large Hadron Collider, a search for evidence of extra spatial dimensions has been performed through an analysis of the diphoton final state. The analysis uses data corresponding to an integrated luminosity of 2.12 fb^-1 of sqrt(s) = 7 TeV proton-proton collisions. The diphoton invariant mass spectrum is observed to be in good agreement with the expected Standard Model background. In the large extra dimension scenario of Arkani-Hamed, Dimopoulos and Dvali, the results provide 95% CL lower limits on the fundamental Planck scale between 2.27 and 3.53 TeV, depending on the number of extra dimensions and the theoretical formalism used. The results also set 95% CL lower limits on the lightest Randall-Sundrum graviton mass of between 0.79 and 1.85 TeV, for values of the dimensionless coupling k/\bar{M}_{Pl} varying from 0.01 to 0.1. Combining with previously published ATLAS results from the dielectron and dimuon final states, the 95% CL lower limit on the Randall-Sundrum graviton mass for k/\bar{M}_{Pl} = 0.01 (0.1) is 0.80 (1.95) TeV.

International audience, According to the Convention on Biological Diversity (CBD), states have to provide indicators in order to assess the performance of their initiatives for halting the loss of biodiversity. Sixteen headline indicators have been identified for monitoring the CBD targets. Of these indicators only one, "Trends in the abundance and distribution of selected species," is a direct headline indicator of "non-exploited" biodiversity. In France, the implementation of this indicator is completely dependent on data collected by volunteers. Since this investment of volunteer time is equivalent to savings in administrative costs, we attempt in this paper to assign it a monetary value. This enables us to estimate how much the French administration saves thanks to volunteer efforts and how much public funding would have to be invested if volunteers were no longer willing to participate in these biodiversity monitoring schemes. We estimate this amount to be between 678,523 and 4,415,251 euros per year, depending on the scenario selected. (C) 2010 Elsevier B.V. All rights reserved.

International audience, Moments and moment invariants have become a powerful tool in pattern recognition and image analysis. Conventional methods to deal with color images are based on RGB decomposition or graying, which may lose some significant color information. In this paper, by using the algebra of quaternions, we introduce the quaternion Zernike moments (QZMs) to deal with the color images in a holistic manner. It is shown that the QZMs can be obtained from the conventional Zernike moments of each channel. We also provide the theoretical framework to construct a set of combined invariants with respect to rotation, scaling and translation (RST) transformation. Experimental results are provided to illustrate the efficiency of the proposed descriptors.

International audience, Highly compacted sand-bentonite mixtures are often considered as possible engineered barriers in deep high-level radioactive waste disposals. In-situ, the saturation of these barriers from their initially unsaturated state is a complex hydro-mechanical coupled process in which temperature effects also play a role. The key parameter of this process is the unsaturated hydraulic conductivity of the barrier. In this paper, isothermal infiltration experiments were conducted to determine the unsaturated hydraulic conductivity according to the instantaneous profile method. To do so, total suction changes were monitored at different locations along the soil specimen by using resistivity relative humidity probes. Three constant volume infiltration tests were conducted showing, unexpectedly, a decrease of the hydraulic conductivity during infiltration. One test performed under free-swell conditions showed the opposite and standard trend. These observations were interpreted in terms of microstructure changes during wetting, both under constant volume and free swell conditions.

International audience, This paper studies the optimal unemployment insurance for older workers in a repeated principal-agent model, where the search intensity of risk-averse workers (the agents) is not observed by the risk-neutral insurance agency (the principal). When unemployment benefits are the only available tool, the insurance agency is not able to induce older workers to search for a job. This is because of the short time-horizon of workers close to retirement. We propose to introduce a pension tax dependent on the length of the unemployment spell. We show that this device performs better than a wage tax after re-employment. First, it makes jobs more attractive, as they are free of tax. Second, because re-employment will be short-lived, a pension tax is a more powerful incentive than a wage tax, and provides more substantial fiscal gains to the agency. Finally, a pension tax allows those workers near retirement who still do not exercise job search to smooth their consumption during their unemployment spell, as if they could borrow against their future pension.

See paper for full list of authors - 8 pages plus author list (20 pages total), 2 figures, 3 tables, submitted to Physics Letters B, Using data recorded in 2011 with the ATLAS detector at the Large Hadron Collider, a search for evidence of extra spatial dimensions has been performed through an analysis of the diphoton final state. The analysis uses data corresponding to an integrated luminosity of 2.12 fb^-1 of sqrt(s) = 7 TeV proton-proton collisions. The diphoton invariant mass spectrum is observed to be in good agreement with the expected Standard Model background. In the large extra dimension scenario of Arkani-Hamed, Dimopoulos and Dvali, the results provide 95% CL lower limits on the fundamental Planck scale between 2.27 and 3.53 TeV, depending on the number of extra dimensions and the theoretical formalism used. The results also set 95% CL lower limits on the lightest Randall-Sundrum graviton mass of between 0.79 and 1.85 TeV, for values of the dimensionless coupling k/\bar{M}_{Pl} varying from 0.01 to 0.1. Combining with previously published ATLAS results from the dielectron and dimuon final states, the 95% CL lower limit on the Randall-Sundrum graviton mass for k/\bar{M}_{Pl} = 0.01 (0.1) is 0.80 (1.95) TeV.

standard LaTex; 29 pages; 6 figures, International audience, We continue the classification of the fermionic Z2XZ2 heterotic string vacua with symmetric internal shifts. The space of models is spanned by working with a fixed set of boundary condition basis vectors and by varying the sets of independent Generalized GSO (GGSO) projection coefficients (discrete torsion). This includes the Calabi-Yau like compactifications with (2,2) world-sheet superconformal symmetry, as well as more general vacua with only (2,0) superconformal symmetry. In contrast to our earlier classification that utilized a montecarlo technique to generate random sets of GGSO phases, in this paper we present the results of a complete classification of the subclass of the models in which the four dimensional gauge group arises solely from the null sector. In line with the results of the statistical classification we find a bell shaped distribution that peaks at vanishing net number of generations and with ~15% of the models having three net chiral families. The complete classification reveals a novel spinor-vector duality symmetry over the entire space of vacua. The S <-> V duality interchanges the spinor plus anti-spinor representations with vector representations. We present the data that demonstrates the spinor-vector duality. We illustrate the existence of a duality map in a concrete example. We provide a general algebraic proof for the existence of the S <-> V duality map. We discuss the case of self-dual solutions with an equal number of vectors and spinors, in the presence and absence of E6 gauge symmetry, and present a couple of concrete examples of self-dual models without E6 symmetry.

19 pages. 1 figure, International audience, Classification of the N=1 space-time supersymmetric fermionic Z2XZ2 heterotic-string vacua with symmetric internal shifts, revealed a novel spinor-vector duality symmetry over the entire space of vacua, where the S_t <-> V duality interchanges the spinor plus anti-spinor representations with vector representations. In this paper we demonstrate that the spinor--vector duality exists also in fermionic Z2 heterotic string models, which preserve N=2 space-time supersymmetry. In this case the interchange is between spinorial and vectorial representations of the unbroken SO(12) GUT symmetry. We provide a general algebraic proof for the existence of the S_t <-> V duality map. We present a novel basis to generate the free fermionic models in which the ten dimensional gauge degrees of freedom are grouped into four groups of four, each generating an SO(8) modular block. In the new basis the GUT symmetries are produced by generators arising from the trivial and non--trivial sectors, and due to the triality property of the SO(8) representations. Thus, while in the new basis the appearance of GUT symmetries is more cumbersome, it may be more instrumental in revealing the duality symmetries that underly the string vacua.

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We review the cosmological constraints put by the current CMB experiment including the recent ARCHEOPS data, in the framework of Lambda-CDM and quintessence paradigm. We show that well chosen combinations of constraints from different cosmological observations lead to precise measurements of cosmological parameters. The Universe seems flat with a 70 percents contribution of dark energy with an equation of state very close to those of the vacuum.

The inclusive production of \eta mesons has been studied using 1.6 million hadronic Z decays collected with the L3 detector. The \eta multiplicity per event, the multiplicity for two-jet and three-jet events separately, and the multiplicity in each jet have been measured and compared with the predictions of different Monte Carlo programs. The momentum spectra of \eta in each jet have also been measured. We observe that the measured \eta momentum spectrum in quark-enriched jets agrees well with the Monte Carlo prediction while in gluon-enriched jets it is harder than that predicted by the Monte Carlo models.

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What does it mean to find one's place in a book ? Some authors assert that the web actualises the dream of Emmanuel Kant that reason is an independent entity , where each one of us plays a part in its construction. Is this the core of the enlightment ? In his minor works and his correspondence Kant wrote about the book and about reading. We should distinguish between Kant's own concept and the uses to which it is put today. In his work he speaks of the courage necessary to think, of the publisher's responsibility, of the theoretical and practical components of thought. From the perspective of Kant's writings, we can see that our view of hypertext is too preoccupied with the instrument of communication itself to the detriment of understanding what might be communicated.

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International audience

International audience, Image-guided radiotherapy (IGRT) aims to take into account anatomical variations occurring during irradiation by visualization of anatomical structures. It may consist of a rigid registration of the tumour by moving the patient, in case of prostatic irradiation for example. IGRT associated with intensity-modulated radiotherapy (IMRT) is strongly recommended when high-dose is delivered in the prostate, where it seems to reduce rectal and bladder toxicity. In case of significant anatomical deformations, as in head and neck tumours (tumour shrinking and decrease in volume of the salivary glands), replanning appears to be necessary, corresponding to the adaptive radiotherapy. This should ideally be "monitored" and possibly triggered based on a calculation of cumulative dose, session after session, compared to the initial planning dose, corresponding to the concept of dose-guided adaptive radiotherapy. The creation of "planning libraries" based on predictable organ positions (as in cervical cancer) is another way of adaptive radiotherapy. All of these strategies still appear very complex and expensive and therefore require stringent validation before being routinely applied.

International audience

The data collected at centre-of-mass energies of 188.6 GeV by ALEPH at LEP, corresponding to an integrated luminosity of 176.2 pb-1, are analysed in a search for pair-produced charged Higgs bosons H+/-. Three analyses are employed to select the taunutaunu, taunucs and cscs final states. No evidence for a signal is found. Upper limits are set on the production cross section as a function of the branching fraction BR(H+ to tau nu) and of the mass M(H+), assuming that the sum of the branching ratios is equal to one. In the framework of a two-Higgs-doublet model, charged Higgs bosons with masses below 65.4 GeV/c2 are excluded at 95% confidence level independently of the decay mode.

International audience, The authors present a successful modeling, realization and characterization of a new micro-sensor based on a convenient optical principle, namely an integrated Mach-Zehnder interferometer (MZI). This MZI device is designed with a view to measuring pressure disturbances due to optical path variations. Such a system is arranged in order to work in intensity modulation scheme. Moreover, the MZI is made up of straight and bent rib optical waveguides composed of SU-8 polymer. The mainstay of the device is based on differential measurements performed by a sensing arm arranged with a micromachined membrane and actuated by a given pressure disturbance, while the second arm of the interferometer is considered as a reference one. The main parameters of each element are given by way of two modeling approaches: an optical modeling with a semi-vectorial finite difference method together with a conformal transformation, and a mechanical modeling with a finite-element method associated to the mechanical theory of membranes. So, as the pressure to be measured is applied upon the diaphragm, an optical path variation of the acting arm is induced. After the combination of both signals, the variation at the output of the system is measured. A prototype is characterized by way of a micro-optical injection bench specifically designed to allow an efficient end-fire coupling into the waveguides.

We review the cosmological constraints put by the current CMB experiment including the recent ARCHEOPS data, in the framework of Lambda-CDM and quintessence paradigm. We show that well chosen combinations of constraints from different cosmological observations lead to precise measurements of cosmological parameters. The Universe seems flat with a 70 percents contribution of dark energy with an equation of state very close to those of the vacuum.

NA50, The elaboration of specific media-planning is necessary to communicate with an opinion leader. Opinion leaders in 27 product categories are selected from a 10,000 sample of French representative consumers. Magazine is the favorite media of opinion leaders; the more important is the number of product categories in which a consumer is leaders, the greater the media consumption. Leaders do not systematically prefer the Internet, their preference appears to be category specific. However, a second study conducted among 600 brand website visitors shows that brand sites represent a major information source for the leaders.