L’action ou la contemplation. Note sur la relation de la fille de Thrace au Docteur angélique

If the opposition between “action and contemplation” seems characteristic of the history of philosophy, it also sums up Hannah Arendt’s personal history and philosophy – the diagnosis of the theoretician of the political practice on her contemporaries being eloquent. But the author of the Human condition invites us to reverse the conjunction. Arendt breaks up deliberately with philosophical tradition and particularly with Thomas Aquinas by making these terms exclusive and choosing to think either action (without contemplation) or contemplation (without action). We would like thus to reflect on the relationship between these two thinkers by examining potential echoes of Summa Theologiae within Arendt’s 1958 essay

Leibniz, vérité de Descartes selon Heidegger

Que la pensée cartésienne, plus que n’importe quelle autre, fonde une ère philosophique nouvelle est un point par tous accordé en histoire de la philosophie. Que la portée réelle de l’inauguration cartésienne n’apparaisse pleinement qu’avec Leibniz est en revanche un élément traditionnellement peu soupçonné. C’est pourtant ce que nous enseigne Heidegger, qui admet le premier le caractère décisif de la démarche cartésienne en tant qu’elle ouvre incontestablement les Temps modernes, mais n’en reconnaît pas moins une supériorité essentielle de la pensée leibnizienne en tant qu’elle la poursuit, l’approfondit et l’accomplit. Aussi Leibniz constitue-t-il à ses yeux la vérité de Descartes.That Cartesian thought, more than any other, initiated a new philosophical era, is a point granted by all in the history of philosophy. That the real impact of the Cartesian inauguration should have become fully apparent with Leibniz alone is less common a view. It is, however, what Heidegger teaches : while being the first to admit the decisive character of the Cartesian approach as unquestionably paving the way to Modern Times, he nonetheless accords an essential superiority to the thought of Leibniz insofar as it pursues, deepens and fulfils it. Thus in his view Leibniz constitutes the truth of Descartes

Sedimentation of active colloidal suspensions

In this paper, we investigate experimentally the non-equilibrium steady state of an active colloidal suspension under gravity field. The active particles are made of chemically powered colloids, showing self propulsion in the presence of an added fuel, here hydrogen peroxide. The active suspension is studied in a dedicated microfluidic device, made of permeable gel microstructures. Both the microdynamics of individual colloids and the global stationary state of the suspension under gravity - density profiles, number fluctuations - are measured with optical microscopy. This allows to connect the sedimentation length to the individual self-propelled dynamics, suggesting that in the present dilute regime the active colloids behave as 'hot' particles. Our work is a first step in the experimental exploration of the out-of-equilibrium properties of artificial active systems.Comment: 4 pages, 4 figure

Return words of linear involutions and fundamental groups

We investigate the natural codings of linear involutions. We deduce from the geometric representation of linear involutions as Poincar\'e maps of measured foliations a suitable definition of return words which yields that the set of first return words to a given word is a symmetric basis of the free group on the underlying alphabet $A$. The set of first return words with respect to a subgroup of finite index $G$ of the free group on $A$ is also proved to be a symmetric basis of $G$

A Constraint-based Approach to Web Services Provisioning

In this paper we consider the provisioning problem of Web services. Our framework is based on the existence of an abstract composition, i.e., the way some services of different types can be combined together in order to achieve a given task. Our approach consists in instantiating this abstract representation of a composite Web service by selecting the most appropriate concrete Web services. This instantiation is based on constraint programming techniques which allows us to match the Web services according to a given request. Our proposal performs this instantiation in a distributed manner, i.e., the solvers for each service type are solving some constraints at one level, and they are forwarding the rest of the request (modified by the local solution) to the next services. When a service cannot provision part of the composition, a distributed backtrack mechanism enables to change previous solutions (i.e., provisions). A major interest of our approach is to preserve privacy: solutions are not sent to the whole composition, services know only the services to which they are connected, and parts of the request that are already solved are removed from the next requests. We introduce a specific data structure, namely Message Treatment Structure, for modeling the problem. We show the interest of this data structure to express the general principles of our framework and the related algorithms

10 um wavefront spatial filtering: first results with chalcogenide fibers

Wavefront cleaning by single-mode fibers has proved to be efficient in optical-infrared interferometry to improve calibration quality. For instance, the FLUOR instrument has demonstrated the capability of fluoride glass single-mode fibers in this respect in the K and L bands. New interferometric instruments developped for the mid-infrared require the same capability for the 8-12 um range. We have initiated a program to develop single-mode fibers in the prospect of the VLTI mid-infrared instrument MIDI and of the ESA/DARWIN and NASA/TPF missions that require excellent wavefront quality. In order to characterize the performances of chalcogenide fibers we are developping, we have set up an experiment to measure the far-field pattern radiated at 10 um. In this paper, we report the first and promising results obtained with this new component.Comment: Conference "Interferometry for Optical Astronomy II", SPIE 200

Polymorphism at a Sex-Linked Transcription Cofactor in European Tree Frogs ( Hyla arborea ): Sex-Antagonistic Selection or Neutral Processes?

Nascent sex chromosomes offer a unique opportunity to investigate the evolutionary fate of genes recently trapped in non-recombining segments. A house-keeping gene (MED15) was recently shown to lie on the nascent sex-chromosomes of the European tree frog (Hyla arborea), with different alleles fixed on the X and the Y chromosomes. Here we document a polymorphism (glutamine deletion) in the X copy of the gene, and use population surveys and experimental crosses to test whether this polymorphism is neutral or maintained by sex-antagonistic selection. Tadpoles from parents of known genotypes revealed significant discrepancies from Mendelian inheritance, suggesting possible sex-antagonistic effects under laboratory conditions. Quantitatively, however, these effects did not meet the conditions for polymorphism maintenance. Furthermore, field estimates of female genotypic frequencies did not differ from Hardy-Weinberg equilibrium and allelic frequencies on the X chromosome did not differ between sexes. In conclusion, although sex-antagonistic effects cannot be excluded given the laboratory conditions, the X-linked polymorphism under study appears neutral in the wild. Alternatively, sex-antagonistic selection might still account for the fixation of a male-specific allele on the Y chromosom

Tuberculosis in evolution

International audienc

Methodology for a global bicycle real world accidents reconstruction

The use of the bicycle on a large scale encouraged in the context to develop an eco friendly environment is facing today on a range of barriers. One of these barriers identified by researchers and governments is observed to include ‘road safety’. Hence, it is necessary to set up a protection system for bicyclists especially for the cephalic segment. Currently only few studies are available concerning the head impact loading in case of real accidents. Therefore, the objective of this work is to identify the initial condition of head impact in case of real accident. Head impact velocity and head impact area are extracted and implemented in the last generation of head injury prediction tool to simulate the head trauma by impacting directly the Strasbourg University Finite Element Head Model (SUFEHM) on the vehicle structures. The present study can be divided into three activities i.e. obtain real bicyclist accidents data issued from in depth accident investigation databases, cyclist body kinematic reconstruction to obtain the initial conditions of the head just before the impact and head impact simulation to evaluate the head loading during impact and the injury risk. A total of 26 bicyclists’ accident cases with head injuries have been collected from both a French and a German accident database. For each accident case, body kinematic has been simulated using Madymo® software. Two methodologies and human multibody models were used: 10 accident cases have been reconstructed by IFSTTAR using its owned developed human model and 16 accident cases have been reconstructed by Unistra using the human pedestrian TNO model. The results show that the head is impacted more often on top parietal zone, and the mean impact velocity is 6.8 ± 2.7 m/s with 5.5 ± 3.0 m/s and 3.4 ± 2.1 m/s for normal and tangential components respectively. Among these real accidents, 19 cases have been selected to be simulated by finite element computations by coupling the human head model and a windscreen model whose properties were extracted from literature. All reconstructed head impact gave results in accordance with the damage actually incurred to the victims. The objective of this study is to demonstrate the feasibility of numerical reconstruction as an understanding tool of the head impact conditions in bicyclist's accident cases, and hence providing knowledge for helmet optimization using biomechanical criteria

Thirteen polymorphic microsatellite markers for the European green toad Bufo viridis viridis , a declining amphibian species

We report 13 new polymorphic microsatellite markers for the European green toad Bufo viridis viridis (B. viridis subgroup), a declining amphibian from Central, Southeastern and Eastern Europe. Diversity at these loci estimated for 19 individuals ranged from two to ten alleles. Most of these primers also cross-amplify in related West-Mediterranean green toad species (Bufo balearicus, B. siculus and B. boulengeri). These microsatellites will be useful for conservation genetics of threatened Bufo viridis viridis populations and evolutionary studies of green toad taxa in secondary contact to examine hybridizatio