Maximal differential uniformity polynomials

We provide an explicit infinite family of integers $m$ such that all the polynomials of ${\mathbb F}_{2^n}[x]$ of degree $m$ have maximal differential uniformity for $n$ large enough. We also prove a conjecture of the third author in these cases

La plus-value des loisirs des éducateurs sociaux et des éducatrices sociales en milieu institutionnel

Dans ce travail, nous abordons la question des loisirs en institution et la fonction qu’ils peuvent avoir auprès des éducateurs sociaux et éducatrices sociales ainsi qu’auprès des bénéficiaires. Ayant chacune eu l’occasion de pratiquer notre loisir en institution, c’est suite à notre première formation pratique que le thème de notre recherche est né. Nous nous sommes questionnées quant à la potentielle plus-­‐value du partage des passions amenées par les professionnel·le·s en institution sociale. Nous avons décidé de développer dans la première partie du travail quatre concepts en lien avec notre question de recherche : les loisirs, la créativité et l’expression, la motivation et l’apprentissage social. Lors de nos analyses, nous avons mis en lumière les propos des professionnel·le·s, recueillis lors de nos entretiens sur le sujet, en y alliant les théories développées dans les concepts. Au terme de notre recherche, notre travail démontre que le fait d’utiliser son loisir ou sa passion dans l’action éducative peut apporter différents bienfaits autant pour les professionnel·le·s que pour les bénéficiaires (motivation, création de lien, compétences supplémentaires etc.). Nous concluons ce travail en exposant nos résultats, en décrivant notre processus et notre démarche de recherche ainsi qu’en proposant certaines pistes d’action

Condensation of helium in aerogels and athermal dynamics of the Random Field Ising Model

High resolution measurements reveal that condensation isotherms of $^4$He in a silica aerogel become discontinuous below a critical temperature. We show that this behaviour does not correspond to an equilibrium phase transition modified by the disorder induced by the aerogel structure, but to the disorder-driven critical point predicted for the athermal out-of-equilibrium dynamics of the Random Field Ising Model. Our results evidence the key role of non-equilibrium effects in the phase transitions of disordered systems.Comment: 5 p + suppl. materia

ALGEBRAIC GEOMETRY CODES OVER ABELIAN SURFACES CONTAINING NO ABSOLUTELY IRREDUCIBLE CURVES OF LOW GENUS

We provide a theoretical study of Algebraic Geometry codes constructed from abelian surfaces defined over finite fields. We give a general bound on their minimum distance and we investigate how this estimation can be sharpened under the assumption that the abelian surface does not contain low genus curves. This approach naturally leads us to consider Weil restrictions of elliptic curves and abelian surfaces which do not admit a principal polarization

Flavivirus reverse genetic systems, construction techniques and applications: A historical perspective

AbstractThe study of flaviviruses, which cause some of the most important emerging tropical and sub-tropical human arbovirus diseases, has greatly benefited from the use of reverse genetic systems since its first development for yellow fever virus in 1989. Reverse genetics technology has completely revolutionized the study of these viruses, making it possible to manipulate their genomes and evaluate the direct effects of these changes on their biology and pathogenesis. The most commonly used reverse genetics system is the infectious clone technology. Whilst flavivirus infectious clones provide a powerful tool, their construction as full-length cDNA molecules in bacterial vectors can be problematic, laborious and time consuming, because they are often unstable, contain unwanted induced substitutions and may be toxic for bacteria due to viral protein expression. The incredible technological advances that have been made during the past 30years, such as the use of PCR or new sequencing methods, have allowed the development of new approaches to improve preexisting systems or elaborate new strategies that overcome these problems. This review summarizes the evolution and major technical breakthroughs in the development of flavivirus reverse genetics technologies and their application to the further understanding and control of these viruses and their diseases

Critical behavior of the liquid gas transition of 4 He confined in a silica aerogel

6 pagesInternational audienceWe have studied 4 He confined in a 95% porosity silica aerogel in the vicinity of the bulk liquid gas critical point. Both thermodynamic measurements and light scattering experiments were performed to probe the effect of a quenched disorder on the liquid gas transition, in relation with the Random Field Ising Model (RFIM). We find that the hysteresis between condensation and evaporation present at lower temperatures disappears at a temperature T ch between 25 and 30 mK below the critical point. Slow relaxations are observed for temperatures slightly below T ch , indicating that some energy barriers, but not all, can be overcome. Above T ch , no density step is observed along the (reversible) isotherms, showing that the critical behavior of the equilibrium phase transition in presence of disorder, if it exists, is shifted to smaller temperatures, where it cannot be observed due to the impossibility to reach equilibrium. Above T ch , light scattering exhibits a weak maximum close to the pressure where the isotherm slope is maximal. This behavior can be accounted for by a simple model incorporating the compression of 4 He close to the silica strands