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

Three Dimensional Raman Cooling using Velocity Selective Rapid Adiabatic Passage

We present a new and efficient implementation of Raman cooling of trapped atoms. It uses Raman pulses with an appropriate frequency chirp to realize a velocity selective excitation through a rapid adiabatic passage. This method allows to address in a single pulse a large number of non zero atomic velocity classes and it produces a nearly unity transfer efficiency. We demonstrate this cooling method using cesium atoms in a far-detuned crossed dipole trap. Three-dimensional cooling of $1 \times 10^{5}$ atoms down to $2 \mu$K is performed in 100 ms. In this preliminary experiment the final atomic density is $1.3\times 10^{12}$ at/cm$^3$ (within a factor of 2) and the phase-space density increase over the uncooled sample is 20. Numerical simulations indicate that temperatures below the single photon recoil temperature should be achievable with this method.Comment: OSA TOPS on Ultracold Atoms and BEC 7 (1997) 5

The palindromization map

The palindromization map has been defined initially by Aldo de Luca in the context of Sturmian words. It was extended to the free group of rank $2$ by Kassel and the second autho We extend their construction to arbitrary alphabets. We also investigate the suffix automaton and compact suffix automaton of the words obtained by palindromization

Timed Specification For Web Services Compatibility Analysis

AbstractWeb services are becoming one of the main technologies for designing and building complex inter-enterprise business applications. Usually, a business application cannot be fulfilled by one Web service but by coordinating a set of them. In particular, to perform a coordination, one of the important investigations is the compatibility analysis. Two Web services are said compatible if they can interact correctly. In the literature, the proposed frameworks for the services compatibility checking rely on the supported sequences of messages. The interaction of services depends also on other properties, such that the exchanged data flow. Thus, considering only supported sequences of messages seems to be insufficient. Other properties on which the services interaction can rely on, are the temporal constraints. In this paper, we focus our interest on the compatibility analysis of Web services regarding their (1) supported sequences of messages, (2) the exchanged data flow, (3) constraints related to the exchanged data flow and (4) the temporal requirements. Based on these properties, we study three compatibility classes: (i) absolute compatibility, (ii) likely compatibility and (iii) absolute incompatibility

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

Bifix codes and interval exchanges

We investigate the relation between bifix codes and interval exchange transformations. We prove that the class of natural codings of regular interval echange transformations is closed under maximal bifix decoding.Comment: arXiv admin note: substantial text overlap with arXiv:1305.0127, arXiv:1308.539

L’impensé du je pense : l’explication heideggérienne du principe cartésien

Évidente pour qui la profère mais déroutante pour qui la considère, la plus célèbre des propositions de la philosophie, cogito, ergo sum, n’a pu manquer d’interroger Heidegger, pour qui elle s’avère « sujette à tous malentendus imaginables ». Aussi, que ce soit en étudiant, au début des années 1920, la philosophie chrétienne où elle se prépare ou, à la fin des années 1930, la philosophie moderne où elle se déclare, celui-ci n’a-t-il jamais cessé de la méditer, afin et de l’expliquer, et de s’expliquer avec elle. C’est l’histoire de cette explication – à la fois interprétation et confrontation – qu’il s’agit ici de retracer, en soulignant comment et combien, derrière le dit cartésien, Heidegger explicite moins ce qu’a pensé son auteur que ce qu’il a laissé non dit, sinon impensé.Clear to anyone who uses it but nevertheless disturbing for all who examine it, philosophy’s most famous proposition, “cogito, ergo sum” drew Heidegger’s attention. For the philosopher, it proved “subject to all possible misunderstandings”. Whether studying, in the early 1920s, Christian philosophy when it was taking shape or, in the late 1930s, modern philosophy when it was formulated, he never stopped thinking about it so as to explain it and to explain himself with it. The history of this explanation – both a confrontation and an interpretation – is retraced here, highlighting how and to what extent, behind the Cartesian statement, Heidegger gives less insight into what his author thought than to what he left unsaid or did not even think

Faire l’amour

"Faire l’amour", qu’est-ce à dire ? Ou plutôt, "faire l’amour", qu’est-ce à faire ? C’est que cette expression toute faite fait de l’amour une praxis sur laquelle l’histoire de la philosophie, pudique, est restée laconique, elle à qui il peut arriver, certes, d’évoquer l’amour, mais toujours comme passion, émotion, sentiment, et rarement comme action, exercice ou épreuve finalement. C’est cet aspect de "la chose" qu’il s’agira ici d’étudier pour la déterminer. Il ne sera donc question au fond que de définition

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