Addendum to "Local Controllability of the Two-Link Magneto-Elastic Micro-Swimmer"

In the above mentioned note (, , published in IEEE Trans. Autom. Cont., 2017), the first and fourth authors proved a local controllability result around the straight configuration for a class of magneto-elastic micro-swimmers.That result is weaker than the usual small-time local controllability (STLC), and the authors left the STLC question open. The present addendum closes it by showing that these systems cannot be STLC

Creationist Conceptions in 14 Countries. How to Teach Evolution to French Students Coming from Immigration?

International audienceEven in France, where creationist ideas are not widespread, more and more teachers are confronted to some difficulties when teaching the biological evolution, mainly with students coming from families immigrated from North Africa or Sub-Saharan Africa. In a first part, to better realize the conflict between the French culture and their African initial culture, we will present some results analyzing the creationist ideas of teachers in 14 countries (n = 5706), including France and 5 African countries (Morocco, Algeria, Tunisia, Senegal and Burkina Faso). We will then analyze the creationist conceptions of 17-18 year old students in a high school of the suburb of Lyon (France) and the main epistemological and socio-cultural obstacles to learning evolution. We will finally present the new strategies of two teachers (biology and philosophy) to help their students to accept the idea that biological evolution is not in contradiction with their possible belief in God, science and religion being two distinct areas

Real-Time Distributed Aircraft Simulation through HLA

This paper presents some ongoing researches carried out in the context of the PRISE (Research Platform for Embedded Systems Engineering) Project. This platform has been designed to evaluate and validate new embedded system concepts and techniques through a special hardware and software environment. Since many actual embedded equipments are not available, their corresponding behavior is simulated using the HLA architecture, an IEEE standard for distributed simulation, and a Run-time infrastructure called CERTI and developed at ONERA. HLA is currently largely used in many simulation applications, but the limited performances of the RTIs raises doubts over the feasibility of HLA federations with real-time requirements. This paper addresses the problem of achieving real-time performances with HLA. Several experiments are discussed using well-known aircraft simulators such as the Microsoft Flight Simulator, FlightGear, and X-plane connected with the CERTI Run-time Infrastructure. The added value of these activities is to demonstrate that according to a set of innovative solutions, HLA is well suited to achieve hard real time constraints

Trusting Computations: a Mechanized Proof from Partial Differential Equations to Actual Program

Computer programs may go wrong due to exceptional behaviors, out-of-bound array accesses, or simply coding errors. Thus, they cannot be blindly trusted. Scientific computing programs make no exception in that respect, and even bring specific accuracy issues due to their massive use of floating-point computations. Yet, it is uncommon to guarantee their correctness. Indeed, we had to extend existing methods and tools for proving the correct behavior of programs to verify an existing numerical analysis program. This C program implements the second-order centered finite difference explicit scheme for solving the 1D wave equation. In fact, we have gone much further as we have mechanically verified the convergence of the numerical scheme in order to get a complete formal proof covering all aspects from partial differential equations to actual numerical results. To the best of our knowledge, this is the first time such a comprehensive proof is achieved.Comment: N° RR-8197 (2012). arXiv admin note: text overlap with arXiv:1112.179

The flitting of electrons in complex I: A stochastic approach

AbstractA stochastic approach based on the Gillespie algorithm is particularly well adapted to describe the time course of the redox reactions that occur inside the respiratory chain complexes because they involve the motion of single electrons between the individual unique redox centres of a given complex. We use this approach to describe the molecular functioning of the peripheral arm of complex I based on its known crystallographic structure and the rate constants of electron tunnelling derived from the Moser and Dutton phenomenological equations. There are several possible electrons pathways but we show that most of them take the route defined by the successive sites and redox centres: NADH+ site – FMN – N3 – N1b – N4 – N5 – N6a – N6b – N2 – Q site. However, the electrons do not go directly from NADH towards the ubiquinone molecule. They frequently jump back and forth between neighbouring redox centres with the result that the net flux of electrons through complex I (i.e. net number of electrons reducing a ubiquinone) is far smaller than the number of redox reactions which actually occur. While most of the redox centres are reduced in our simulations the degree of reduction can vary according to the individual midpoint potentials. The high turnover number observed in our simulation seems to indicate that, in the whole complex I, one or several slower step(s) follow(s) the redox reactions involved in the peripheral arm. It also appears that the residence time of FMNH• and SQ• (possible producers of ROS) is low (around 4% and between 1.6% and 5% respectively according to the values of the midpoint potentials). We did not find any evidence for a role of N7 which remains mainly reduced in our simulations. The role of N1a is complex and depends upon its midpoint potential. In all cases its presence slightly decreases the life time of the flavosemiquinone species. These simulations demonstrate the interest of this type of model which links the molecular physico-chemistry of the individual redox reactions to the more global level of the reaction, as is observed experimentally

Parmentier, las patatas y las ollas americanas

The discovery of new agricultural and alimentary possibilities was one of the most important motives of the numerous scientific expeditions sent to America during the XVIIIth Century. Some French scientists (naturalists, medical, botanical, etc.,) undertook, during the second half of the Enlightment Century, an active campaign in favor of the potato consumption. The most well-known was the pharmacist Parmentier that settled his propaganda upon political arguments (the potato gives of eating all the population), economical (it is an easy plant of cultivating and of good efficiency), and scientific (excellent nutritious qualities).El descubrimiento de nuevas posibilidades agroalimentarias fue uno de los más importantes motivos de las numerosas expediciones científicas enviadas a América durante el siglo XVIII. Algunos científicos galos (naturalistas, médicos, botánicos, etc.,) emprendieron, en la segunda mitad del siglo de las Luces, una activa campaña en favor del consumo de la patata por los hombres. El más conocido fue el farmacéutico Parmentier, que asentó su propaganda sobre argumentos políticos (la patata da de comer a toda la población), económicos (es una planta fácil de cultivar y de buen rendimiento), y científicos (excelentes cualidades nutritivas)

Télédétection et caractéristiques physiques des dépôts meubles dans un milieu anciennement englacé du sud du Québec

L'analyse géomorphologique à partir de bandes spectrales débordant le rayonnement visible est encore au stade expérimental. La stratigraphie et la structure interne des dépôts meubles ne peuvent être directement détectées, mais la granulométrie et les formes de surface peuvent l'être. Dans le cas des surfaces dénudées, la granulométrie est reliée à la réflectance dans le visible et le proche infrarouge et à la rugosité détectable par le radar. Dans le cas des surfaces recouvertes de végétation, la granulométrie peut être déduite indirectement des conditions d'humidité des sols, qui commandent l'alimentation en eau des plantes, dans le visible, le proche infrarouge, l'infrarouge thermique, le radar (constante diélectrique) et théoriquement les micro-ondes passives. Sans compter la traditionnelle photointerprétation stéréoscopique, les formes de surface peuvent être reconnues soit de façon automatisée, surtout dans le cas des formes linéaires, lorsque l'on possède des documents numérisés, soit de façon visuelle par rehaussement d'image lors de la prise de vue (radar, thermographies). Les formes de surface peuvent aussi être rehaussées au moment du traitement par incorporation d'un modèle numérique de terrain ou avec des images de composantes spectrales. Des expériences ont été conduites en Estrie afin de distinguer les tills des dépôts fluvioglaciaires ou glacio-lacustres. Il en résulte que l'imagerie la plus efficace dans le cas d'une analyse visuelle est l'infrarouge thermique diurne en automne quand les effets de l'insolation sur la topographie sont maximaux et où ceux des écarts d'albédo sont réduits.Géomorphologie analysis based on or using spectral bands beyond the visible is still at an experimental stage. If stratigraphy and internal structure of surficial deposits cannot be directly detected, grain size and surface landforms are detectable, however. In the case of non vegetated areas, grain size is related to visible and near infrared reflectance, and to surface roughness detectable by airborne radar. In the case of vegetated surfaces, grain size can be inferred indirectly from soil moisture conditions which are detectable in the visible, near infrared, thermal infrared, radar (dielectric constant) and theoretically in the passive microwave spectral ranges. Besides traditional stereoscopic photointerpretation, surface landforms, especially linear ones, can be recognized either automatically, if digital data are available, or visually through enhancements generated in numerical analysis by data acquisition methods (radar, thermography). Surface landforms can also be enhanced by incorporation of a digital terrain model or by principal component enhancement. Experiments have been conducted in the Eastern Townships of Québec, in order to distinguish glacial tills from fluvioglacial or lacustrine deposits. The most efficient imagery for this purpose, using visual analysis, is daytime thermal infrared, acquired during the Fall, when insolation effects on topography are greatest and albedo variations are least.Geomorphologische Analyse die sich auf den Gebrauch, von ausserhalb des Sichtbaren liegenden spectralen Streifen grùndet, ist noch im Experimentalstadium. Wenn auch Stratigraphie und innere Struktur der Oberflàchen Ablagerungen nicht direkt untersucht werden kônnen, sind jedoch Korngrôsse und Oberflàchen Landformen untersuchbar. Im FaIIe von nicht Vegetations gedeckten Gegenden, ist die Korngrôsse verbunden mit der sichtbaren und nahinfraroten Reflektanz und mit der Oberflàchen Rauheit, welche mit dem Radar detektiert werden kann. Im FaIIe von Vegetations bedeckten Gegenden kann die Korngrôsse durch die Bodenfeuchtigkeits Verhâltnisse, welche durch die sichtbaren, nahinfraroten, thermal infraroten, Radar (dielektrische Konstante) und theoretisch in dem passiven Mikrowellen spektral Raum, angenommen werden kônnen. Neben der traditionellen stereoskopischen Photo-interpretation, Oberflachenlandformen, besonders lineâre, kônnen entweder automatisch erkannt werden, wenn digital Daten vorhanden sind, oder visuele, durch das Erheben des Bildes bei der Aufnahme (Radar, Thermographie). Die Oberflàchenformen kônnen auch verbessert werden durch das Einschliessen von digitalen Terrain-Modellen oder durch Hauptkomponenten Verbesserung. In den Cantons de l'Est in Québec, wurden Expérimente durchgefùhrt, urn glazialen Till von fluvioglazialen oder lakustrinen Ablagerungen zu unterscheiden. Es ergiebt sich, dass die leistungsfàhigsten Abbildungen fur eine visuelle Analyse vom thermischen, Tagesinfrarot stammen im Herbst, wenn die Einflusse der Sonnenbestrahlung auf die Topographie am grôssten sind, und die der albedo Abweichungen reduziert sind

COSMO (“Communicating about Objects using Sensory–Motor Operations”): A Bayesian modeling framework for studying speech communication and the emergence of phonological systems

International audienceWhile the origin of language remains a somewhat mysterious process, understanding how human language takes specific forms appears to be accessible by the experimental method. Languages, despite their wide variety, display obvious regularities. In this paper, we attempt to derive some properties of phonological systems (the sound systems for human languages) from speech communication principles. We introduce a model of the cognitive architecture of a communicating agent, called COSMO (for “Communicating about Objects using Sensory–Motor Operations') that allows a probabilistic expression of the main theoretical trends found in the speech production and perception literature. This enables a computational comparison of these theoretical trends, which helps us to identify the conditions that favor the emergence of linguistic codes. We present realistic simulations of phonological system emergence showing that COSMO is able to predict the main regularities in vowel, stop consonant and syllable systems in human languages