Dielectric constant of glasses: first observation of a two-dimensional behavior

The 1kHz real part $\chi'$ of the dielectric constant of a structural glass was measured at low temperature $T$ down to 14 mK. Reducing the sample thickness $h$ to 10 nm suppresses the usual minimum of $\chi'$ for measuring fields $E<.5$ MV/m. This contradicts the Two Level System (TLS) model but is well accounted for by including TLS-TLS interactions where excitations delocalize between TLS's through a $E$-induced mechanism recently designed: for small $h$'s this interaction is reduced, which explains the two-dimensional behavior of $\chi'(T)$. Hence, interactions play a key role in standard thick samples.Comment: latex finesse3.tex, 5 files, 4 figures, 4 pages [SPEC-S02/050], submitted to Phys. Rev. Let

Properties of age compositions and mortality estimates derived from cohort slicing of length data

Cohort slicing can be used to obtain catch-at-age data from length frequency distributions when directly measured age data are unavailable. The procedure systematically underestimates the relative abundance of the youngest age groups and overestimates abundance at older ages. Cohort-sliced catch-at-age data can be used to estimate total mortality rate (Z) using a regression estimator or the Chapman-Robson estimator for right truncated data. However, the effect of cohort slicing on accuracy and precision of resulting Z estimates remains to be determined. We used Monte Carlo simulation to estimate the per cent bias and per cent root mean square error of the unweighted regression, weighted regression, and Chapman-Robson mortality estimators applied to cohort-sliced data. Incompletely recruited age groups were truncated from the cohort-sliced catch-at-age data using previously established recommendations and a variety of plus groups was used to combine older age groups. The sensitivity of the results to a range of plausible biological combinations of Z, growth parameters, recruitment variability, and length-at-age error was tested. Our simulation shows that cohort slicing can work well in some cases and poorly in others. Overall, plus group selection was more important in high K scenarios than it was in low K scenarios. Surprisingly, defining the plus group to start at a high age worked well in some cases, although length and age are poorly correlated for old ages. No one estimator was uniformly superior; we therefore provide recommendations concerning the appropriate estimator and plus group to use, depending on the parameters characterizing the stock. We further recommend that simulations be performed to determine exactly which plus group would be most appropriate given the scenario at hand

Development and Validation of a Five Stroke Engine

International audienc

Genomic definition of hypervirulent and multidrug-resistant Klebsiella pneumoniae clonal groups.

International audienceMultidrug-resistant and highly virulent Klebsiella pneumoniae isolates are emerging, but the clonal groups (CGs) corresponding to these high-risk strains have remained imprecisely defined. We aimed to identify K. pneumoniae CGs on the basis of genome-wide sequence variation and to provide a simple bioinformatics tool to extract virulence and resistance gene data from genomic data. We sequenced 48 K. pneumoniae isolates, mostly of serotypes K1 and K2, and compared the genomes with 119 publicly available genomes. A total of 694 highly conserved genes were included in a core-genome multilocus sequence typing scheme, and cluster analysis of the data enabled precise definition of globally distributed hypervirulent and multidrug-resistant CGs. In addition, we created a freely accessible database, BIGSdb-Kp, to enable rapid extraction of medically and epidemiologically relevant information from genomic sequences of K. pneumoniae. Although drug-resistant and virulent K. pneumoniae populations were largely nonoverlapping, isolates with combined virulence and resistance features were detected

Pour une didactique du théâtre : entre textes, jeux et représentations

Intitulé « Pour une didactique du théâtre : entre textes, jeux et représentations », cette nouvelle livraison de Pratiques complète la précédente dont elle représente le volet didactique. La première partie (« Approche historique et institutionnelle »), cherche à rendre compte des changements qu’a connus l’enseignement du théâtre au niveau du secondaire. Outre l’observation des Textes Officiels et des recommandations des manuels à ce sujet, on s’intéresse plus particulièrement à la fortune de Tartuffe dans les manuels du lycée depuis le début du XXe siècle jusqu’à nos jours. Dans cette même partie, on étudie les discours institutionnels à propos de l’enseignement du théâtre dans le secondaire d’aujourd’hui (programmes, concours de recrutement externes et internes, ressources numériques). Avec la seconde partie (« Réflexions théoriques et didactiques »), on propose une vision d’ensemble de l’enseignement du théâtre qui prend en compte la triple dimension du théâtre, comme texte, jeu et représentation. On met aussi en débat les théories du sujet lecteur confronté aux textes dramatiques et on réfléchit à une possible formation d’un sujet-spectateur. Pour la troisième partie (« Le théâtre à l’école, au lycée et en formation »), il s’agit, selon les différents ordres d’enseignement, à la fois de faire un bilan des pratiques d’enseignement du théâtre et de rendre compte d’expériences concrètes réalisées. Une place importante est accordée au répertoire contemporain pour la jeunesse et à son exploitation en classe. On insiste aussi sur l’importance du jeu dramatique au lycée et sur l’enseignement de la dramaturgie selon les lieux de formation initiale et continue en dialogue avec le savoir et l’expérience de professionnels, ici avec É. Ruf, comédien, metteur en scène, scénographe et administrateur de la Comédie Française. Le numéro est complété par des articles publiés en Varia. Entitled "Pour une didactique du théâtre : entre textes, jeux et représentations", this new issue of Pratiques completes the previous one of which it represents the didactic part. The first part ("Historical and institutional approach"), seeks to account for the changes that have occurred in the teaching of theater at the secondary level. In addition to the observation of the Official Texts and the recommendations of the textbooks on this subject, we are particularly interested in the fortune of Tartuffe in the textbooks of the high school since the beginning of the XXth century until now. In this same part, we study the institutional discourses about the teaching of theater in today's high school (programs, external and internal recruitment competitions, digital resources). The second part ("Theoretical and didactic reflections") proposes an overall vision of theater teaching that takes into account the triple dimension of theater as text, play and performance. It also debates the theories of the subject-reader confronted with dramatic texts and reflects on the possible formation of a subject-spectator. The third part ("Theatre in school, high school and training"), according to the different levels of education, is both an assessment of theater teaching practices and an account of concrete experiences. A great deal of emphasis is placed on contemporary repertoire for young people and its use in the classroom. We also emphasize the importance of acting in high school and the teaching of drama in initial and continuing education settings in dialogue with the knowledge and experience of professionals, in this case with É. Ruf, actor, director, set designer and administrator of the Comédie Française. The issue is completed by articles published in Varia

The eggplant AG91-25 recognizes the Type III-secreted effector RipAX2 to trigger resistance to bacterial wilt (Ralstonia solanacearum species complex).

International audienceTo deploy durable plant resistance, we must understand its underlying molecular mechanisms. Type III effectors (T3Es) and their recognition play a central role in the interaction between bacterial pathogens and crops. We demonstrate that the Ralstonia solanacearum species complex (RSSC) T3E ripAX2 triggers specific resistance in eggplant AG91-25, which carries the major resistance locus EBWR9. The eggplant accession AG91-25 is resistant to the wild-type R. pseudosolanacearum strain GMI1000, whereas a ripAX2 defective mutant of this strain can cause wilt. Notably, the addition of ripAX2 from GMI1000 to PSS4 suppresses wilt development, demonstrating that RipAX2 is an elicitor of AG91-25 resistance. RipAX2 has been shown previously to induce effector-triggered immunity (ETI) in the wild relative eggplant Solanum torvum, and its putative zinc (Zn)-binding motif (HELIH) is critical for ETI. We show that, in our model, the HELIH motif is not necessary for ETI on AG91-25 eggplant. The ripAX2 gene was present in 68.1% of 91 screened RSSC strains, but in only 31.1% of a 74-genome collection comprising R. solanacearum and R. syzygii strains. Overall, it is preferentially associated with R. pseudosolanacearum phylotype I. RipAX2(GMI1000) appears to be the dominant allele, prevalent in both R. pseudosolanacearum and R. solanacearum, suggesting that the deployment of AG91-25 resistance could control efficiently bacterial wilt in the Asian, African and American tropics. This study advances the understanding of the interaction between RipAX2 and the resistance genes at the EBWR9 locus, and paves the way for both functional genetics and evolutionary analyses