L’ostéogenèse imparfaite: à propos d’un cas

L'ostéogenèse imparfaite est une maladie héréditaire caractérisée par une fragilité osseuse secondaire à un défaut de synthèse du collagène de type I. Le diagnostic est suspecté devant des signes échographiques évocateurs et confirmé par une étude génétique. Nous rapportons un cas d'ostéogenèse imparfaite de découverte tardive au troisième trimestre chez une patiente qui n'a pas suivi sa grossesse

Doublet structures in quantum well absorption spectra due to Fano-related interference

In this theoretical investigation we predict an unusual interaction between a discrete state and a continuum of states, which is closely related to the case of Fano-interference. It occurs in a GaAs/AlxGa1-xAs quantum well between the lowest light-hole exciton and the continuum of the second heavy-hole exciton. Unlike the typical case for Fano-resonance, the discrete state here is outside the continuum; we use uniaxial stress to tune its position with respect to the onset of the continuum. State-of-the art calculations of absorption spectra show that as the discrete state approaches the continuum, a doublet structure forms which reveals anticrossing behaviour. The minimum separation energy of the anticrossing depends characteristically on the well width and is unusually large for narrow wells. This offers striking evidence for the strong underlying valence-band mixing. Moreover, it proves that previous explanations of similar doublets in experimental data, employing simple two-state models, are incomplete.Comment: 21 pages, 5 figures and 5 equations. Accepted for publication in Physical Review

The Influence of a Continuum Background on Carrier Relaxation in InAs/InGaAs Quantum Dot

We have investigated the ultra-fast carrier dynamics in Molecular Beam Epitaxy (MBE)-grown InAs/InGaAs/GaAs quantum dots (QDs) emitting at 1.3 μm by time resolved photoluminescence (TRPL) upconversion measurements with a time resolution of about 200 fs. Changing the detection energies in the spectral region from the energy of the quantum dots excitonic transition up to the barrier layer absorption edge, we have found that, under high excitation intensity, the intrinsic electronic states are populated mainly by carriers directly captured from the barrier

Asynchronous simulation of Boolean networks by monotone Boolean networks

International audienceWe prove that the fully asynchronous dynamics of a Boolean network f : {0, 1}^n → {0, 1}^n without negative loop can be simulated, in a very specific way, by a monotone Boolean network with 2n components. We then use this result to prove that, for every even n, there exists a monotone Boolean network f : {0, 1}^n → {0, 1}^n , an initial configuration x and a fixed point y of f such that: (i) y can be reached from x with a fully asynchronous updating strategy, and (ii) all such strategies contains at least 2^{n/2} updates. This contrasts with the following known property: if f : {0, 1}^n → {0, 1}^n is monotone, then, for every initial configuration x, there exists a fixed point y such that y can be reached from x with a fully asynchronous strategy that contains at most n updates

The Laser Astrometric Test of Relativity Mission

This paper discusses new fundamental physics experiment to test relativistic gravity at the accuracy better than the effects of the 2nd order in the gravitational field strength. The Laser Astrometric Test Of Relativity (LATOR) mission uses laser interferometry between two micro-spacecraft whose lines of sight pass close by the Sun to accurately measure deflection of light in the solar gravity. The key element of the experimental design is a redundant geometry optical truss provided by a long-baseline (100 m) multi-channel stellar optical interferometer placed on the International Space Station. The geometric redundancy enables LATOR to measure the departure from Euclidean geometry caused by the solar gravity field to a very high accuracy. LATOR will not only improve the value of the parameterized post-Newtonian (PPN) parameter gamma to unprecedented levels of accuracy of 1 part in 1e8, it will also reach ability to measure effects of the next post-Newtonian order (1/c^4) of light deflection resulting from gravity's intrinsic non-linearity. The solar quadrupole moment parameter, J2, will be measured with high precision, as well as a variety of other relativistic. LATOR will lead to very robust advances in the tests of fundamental physics: this mission could discover a violation or extension of general relativity, or reveal the presence of an additional long range interaction in the physical law. There are no analogs to the LATOR experiment; it is unique and is a natural culmination of solar system gravity experiments.Comment: 8 pages, 2 figures, invited talk given at the Second International Conference on Particle and Fundamental Physics in Space (SpacePart'03), 10-12 December 2003, Washington, D

Modelling web services interoperability

algorithm With the development of the semantic Web, the specification of Web services has evolved from a “remote procedure call ” style to a behavioral description including standard constructors of programming languages. Such a transformation introduces new problems since traditional clients will not be able to interact with these sophisticated services. In this work, we develop a generic agent capable to fully control the interaction process with a Web service given its XLANG behavioral description (XLANG being one of these languages). At first, we give an operational semantic to XLANG in terms of timed transition systems. Then we define a relation between two communicating systems which formalizes the concept of a correct interaction and we propose an algorithm which either detects ambiguity of the Web service or generates a timed deterministic automaton which controls the agent behavior during the interaction with the service. Starting from these theoretical developments we have built a platform which ensures to a user the correct handling of any complex Web service dynamically discovered through the Web.

An Integrated Framework for Web Services Orchestration

Currently, Web services give place to active research and this is due both to industrial and theoretical factors. On one hand, Web services are essential as the design model of applications dedicated to the electronic business. On the other hand, this model aims to become one of the major formalisms for the design of distributed and cooperative applications in an open environment (the Internet). In this paper, we will focus on two features of Web services. The first one concerns the interaction problem: given the interaction protocol of a Web service described in BPEL, how to generate the appropriate client? Our approach is based on a formal semantics for BPEL via process algebra and yields an algorithm which decides whether such a client exists and synthetize the description of this client as a (timed) automaton. The second one concerns the design process of a service. We propose a method which proceeds by two successive refinements: first the service is described via UML, then refined in a BPEL model and finally enlarged with JAVA code using JCSWL, a new language that we introduce here. Our solutions are integrated in a service development framework that will be presented in a synthetic way. KEYWORDS: BPEL, Formal Semantics, Interoperability, Program Synthesis,Language Expressivit

Biochemical characterization, microbial diversity and biodegradability of coastal sediments in the Gulf of Gabès, Southern Mediterranean Sea

International audienceCoastal sediments are considered to be final receptacles for organic and inorganic contaminants. Characterizing those sediments and assessing their biodegradation potential have become a great challenge in recent years. In this study, the chemical composition, including the content in polycyclic aromatic hydrocarbons, the microbial community abundance and diversity (using culture-independent approaches targeting 16S rRNA genes), and the aerobic/anaerobic biodegradation potential of coastal sediments collected in the Sfax coastal area (Gulf of Gabès, Southern Mediterranean Sea) were investigated. The highest concentration of total polycyclic aromatic hydrocarbons (981 µg kg−1 dw) was recorded in Sidi Mansour harbor sediment, emphasized pyrogenic and petrogenic hydrocarbon sources. Organic matter, including total organic carbon, and the ultimate aerobic biodegradability, with 30% as the highest value in Sidi Salem channel sediment, were in a positive accordance with bacterial communities assigned within Actinobacteria, Clostridia and Flavobacteria classes. The correlation noticed between Thermocladium and Thermogladius genera and sulfate content explained that Sidi Mansour and PK4 sediments are located in terrestrial acid–sulfate areas. The highest cumulative methane produced with Marseille inoculum and Tunisian inoculum was recorded in Sidi Salem sediment and strongly correlated with methanogens among Methanobacteria, Methanococci and Methanomicobia classes showing the presence of industrial and municipal sources. The bioavailability of low and moderate polycyclic aromatic hydrocarbons in the current study may explain the occurrence of Methanobacterium which positively correlated with the anaerobic biodegradability using Tunisian inoculum with 50% as the highest value in Sidi Mansour sediment

Distributed Adaptation of Dining Philosophers

Abstract. Adaptation of a component-based system can be achieved in the coordination modelling language Paradigm through the special component McPal. McPal regulates the propagation of new behaviour and guides the changes in the components and in their coordination. Here we show how McPal may delegate part of its control to local adaptation managers, created on-the-fly, allowing for distribution of the adaptation indeed. We illustrate the approach for the well-known example of the dining philosophers problem, by modelling the migration from a deadlock-prone solution to a deadlock-free starvation-free solution without any system quiescence. The adaptation goes through various stages, exhibiting shifting control among McPal and its helpers, and changing degrees of orchestrated and choreographic collaboration.