Le journalisme scientifique dans les controverses

Le journaliste scientifique a-t-il simplement vocation à rendre compte des controverses ? Est-il un acteur à part dans ces débats ? Comment rend-il compte des conflits inhérents et de leur dimension « extra-scientifique » ? Comment fonctionne la chaîne d’information scientifique face à de tels enjeux économiques et politiques ? Les relations entre acteurs, notamment au sein des rédactions, sont-elles reconfigurées en situation de controverse ? Pour répondre à ces questions générales, trois études de ces controverses sont ici ciblées, renvoyant à des préoccupations citoyennes majeures : le changement climatique, les perturbateurs endocriniens et les organismes génétiquement modifiés. Une analyse qui permet de mieux comprendre les controverses, les pratiques des journalistes scientifiques et leur place particulière dans une profession en mutation

An Analysis of Bohm's theorem

We present in this article a detailed analysis of Bhm's theorem, an essentialy separability results in pure l-calculus. The theorem is explained completely constructively as an algorithmic development in the functional programming language ML

A complete proof of correctness of the Knuth-Bendix completion algorithm

summar

The Gilbreath trick : a case study in axiomatisation and proof development in the Coq proof assistant

Projet FORMELRésumé disponible dans le fichier PD

Residual theory in lambda-calculus : a formal development

We present the complete development, in Gallina, of the residual theory of b-reduction in pure l-calculus. The main result is the prism theorem and its corollary Levy's cube lemma, a strong form the parallel-moves lemma, itself a key step towards the confluence theorem and its usual corollaries (Church-Rosser, uniqueness of normal forms). Gallina is the specification language of the Coq proof assistant. It is a specific concrete syntax for its abstract framework, the calculus of inductive constructions. It may be thought of as a smooth mixture of higher-order predicate calculus with recursive definitions, inductively defined data-types and inductive predicate definitions reminiscent of logic programming. The development presented here was fully checked in the current distribution version Coq V5.8. We just state the lemmas in the order in which they are proved, omitting the proof justifications. The full transcript is available as a standard library in the distribution of Coq

Reproduction of the invasive slipper limpet, Crepidula fornicata , in the Bay of Brest, France

The reproduction of Crepidula fornicata was studied in the Bay of Brest in order to characterise the first step of the reproductive cycle of this invasive species. The survey was carried out from 2000 to 2003 and different parameters were measured, namely, the percentage of the different sexual stages, the straight length of the shell and the percentage of brooding females using a survey of the embryonic development and the fecundity. The juvenile frequency increases generally from mid-June or mid-August, depending on the year. In 2001 and 2003, a first peak was observed as early as May, but it was followed by a rapid disappearance of the individuals. The sex-ratio female/male increased from 0.22 to 0.46 between 2001 and 2003. The sex change between intermediates and females took place mainly in summer and was well marked in 2001 and 2003. The survey of the embryonic development in the egg capsules brooded by the females provided an annual phenology of the laying and hatching processes. The laying period extends from February to September with three to four major periods of egg-laying per year and corresponding hatching periods about 1 month later. Each female lays two to four times per year on average. The first egg-laying concerned fewer females than subsequent ones, except in 2003, and exhibited a higher fecundity. The annual mean of the number of eggs for each stage was not significantly different, thus indicating no significant mortality rate during embryonic development. For the C. fornicata population in the Bay of Brest, several reproductive characteristics tend to highlight its invasive capacity: (1) a long reproductive period, (2) reproduction in a ‘multi-trials' process equivalent to a spreading out of the risks and (3) a relatively high fecundit