Extract of the anatomica by René Descartes february 5, 1635

If a body were to be pushed or received an impulse from a force applied evenly by a spirit (in effect, no other type of force could be as even), and if it were to be driven in a void, it would always take three times more time to travel from the beginning of its movement up to the midpoint of the space to be traveled than from the midpoint of the space to its end, and so on. For because no void of this type can be created and because, whatever the existing space, it will always resist in some way: as such, the resistance always increases in geometric proportion to the speed of the movement, such that one ultimately arrives at the point where the speed is not perceptibly augmented and it becomes possible to determine a certain other final speed, to which it will never be equal

An everpresent reference of the XVIITH century intellectual production: Euclid’s elements

Euclid’s Elements, written in the third century BC., during the reign of Ptolemy I, is, second to the Bible, only in number of reprints. Those published in the XVIth and XVIIth centuries are, either philological examinations of the corpus, or the basis of philosophical commentaries, or mathematical treatises or even pedagogical handbooks. Among those very numerous reprints, I shall only quote from the version offered by Christopher Clavius, which, as far as we know, was referred to by all XVII th century specialists. This Euclidean reference fed equally all fields of intellectual production, whether philosophical, mathematical or pedagogical and the Elements was the common, cultural inspiration of mathematicians and natural philosophers from the end of the XVIth century to that of the XVIIth

Geometry in Descartes’ system

What struck the young student of mathematics at the college of La Fleche was the absolute certainty of their demonstrations. More specifically, he was impressed by the contrast between these proofs and the literary tradition, for “/ had compared the moral writings of the ancients pagans to the most proud and magnificent palaces built on nothing but sand and mud”. Still, while he grants the are unquestionable, Descartes discovered both in geometry and arithmetic, an essential useleness and futility, an appreciation he will maintain all throughout his life. These first impressions might account for two emotions “joy and unease” frequently to be found at once in Descartes’ mathematical works. In his work we find a combination of joy of discovery, clear ideas and of mastership over methods, and uneasiness caused by the puerile, futile character of the very mathematical object itself. This ambivalence is present clearly and explicitly throughout Geometry

Pascal via Duhem et van Fraassen

La place discrète de Pascal dans l’histoire de la philosophie des sciences Nous nous intéresserons ici à la physique pascalienne et à l’écho qu’elle a eu dans l’histoire de la discipline. Il est facile de montrer la faible présence de Pascal dans la pensée épistémologique moderne et contemporaine en examinant quelques données puisées dans un échantillon restreint mais significatif de la bibliographie susceptible de présenter ou de commenter l’épistémologie physique pascalienne. Le gros volume..

Foam Drainage Control Using Thermocapillary Stress in a Two-Dimensional Microchamber

International audienceWe investigate the drainage of a 2D microfoam in a vertical Hele-Shaw cell, and show that the Marangoni stress at the air-water interface generated by a constant temperature gradient applied in situ can be tuned to control the drainage. The temperature gradient is applied in such a way that thermocapillarity and gravity have an antagonist e ect. We characterize the drainage over time by measuring the liquid volume fraction in the cell and find that thermocapillarity can overcome the e ect of gravity, e ectively draining the foam towards the top of the cell, or exactly compensate it, maintaining the liquid fraction at its initial value over at least 60 s. We quantify these results by solving the mass balance in the cell, and provide insight on the interplay between gravity, thermocapillarity and capillary pressure governing the drainage dynamics

L’automobile en France : vers la fin d’une vieille industrie ?

Introduction À l’heure de la « nouvelle nouvelle économie », une partie des politiques et des économistes semblent avoir fait leur deuil de l’industrie. L’urgence serait de développer l’économie de la fonctionnalité car, fondamentalement, les clients – entreprises et consommateurs – souhaiteraient accéder à l’usage des biens et non à leur propriété. L’automobile fait fréquemment l’objet d’une telle lecture. Industrie emblématique de la seconde révolution industrielle et des Trente Glorieuses,..

Philosophie naturelle et mathématiques, XVIe-XVIIe siècles

Vincent Jullien, professeur à l’Université de NantesJean Dhombres, directeur d’études Ce séminaire du second semestre avait comme objectif de dresser un bilan des travaux récents, philosophiques et historiques, sur le thème du rôle des mathématiques dans la révolution scientifique, et sur les changements de la philosophie naturelle au XVIIe siècle. Ainsi, furent évoquées les études sur la question de la certitude des mathématiques (XVIe siècle), les nombreuses publications sur la « science jé..

Philosophie naturelle et mathématiques, XVIe-XVIIe siècles

Vincent Jullien, professeur à l’Université de NantesJean Dhombres, directeur d’études Ce séminaire du second semestre avait comme objectif de dresser un bilan des travaux récents, philosophiques et historiques, sur le thème du rôle des mathématiques dans la révolution scientifique, et sur les changements de la philosophie naturelle au XVIIe siècle. Ainsi, furent évoquées les études sur la question de la certitude des mathématiques (XVIe siècle), les nombreuses publications sur la « science jé..

L’inéluctable incomplétude des politiques industrielles régionales et européennes

Fondé sur un travail empirique d’enquête sur les usages des fonds Konver en Lombardie, dans la région de Manchester et en Aquitaine, l’article montre combien les trajectoires passées des régions et la teneur des dispositifs locaux d’action publique ont généré une très forte différenciation des logiques dans lesquelles ces aides ont été employées. Après avoir présenté la diversité des trajectoires des systèmes productifs territoriaux (I) et le rôle tenu dans leur détermination par les politiques publiques régionales (II), nous développons une grille d’analyse sectorielle institutionnaliste qui permet de comprendre pourquoi la place des politiques publiques régionales et européenne demeure marginale dans la définition des trajectoires productives du secteur de la Défense.The article elaborates on an empirical investigation of the use and impact of Konver budgets on local economies in Lombardy (Italy), in the Manchester area (UK), and in Aquitaine (France). The article explains that previous regional development trajectories and institutional arrangements explain the differentiation between uses of Konver budgets with local public policies. The article (1) explores the diversity of trajectories, (2) investigates the rationales for regional policies linked to the conversion of Defense industries, and (3) provides with a neo-institutionalist analysis of the impact of Konver budgets and explains why local and European policies remain of marginal impact on Defense conversion

Designing a paediatric study for an antimalarial drug including prior information from adults

International audienceThe objectives of this study were to design a pharmacokinetic (PK) study by using information about adults and evaluate the robustness of the recommended design through a case study of mefloquine. PK data about adults and children were available from two different randomized studies of the treatment of malaria with the same artesunate-mefloquine combination regimen. A recommended design for pediatric studies of mefloquine was optimized on the basis of an extrapolated model built from adult data through the following approach. (i) An adult PK model was built, and parameters were estimated by using the stochastic approximation expectation-maximization algorithm. (ii) Pediatric PK parameters were then obtained by adding allometry and maturation to the adult model. (iii) A D-optimal design for children was obtained with PFIM by assuming the extrapolated design. Finally, the robustness of the recommended design was evaluated in terms of the relative bias and relative standard errors (RSE) of the parameters in a simulation study with four different models and was compared to the empirical design used for the pediatric study. Combining PK modeling, extrapolation, and design optimization led to a design for children with five sampling times. PK parameters were well estimated by this design with few RSE. Although the extrapolated model did not predict the observed mefloquine concentrations in children very accurately, it allowed precise and unbiased estimates across various model assumptions, contrary to the empirical design. Using information from adult studies combined with allometry and maturation can help provide robust designs for pediatric studies