Fluctuation-dissipation relation on a Melde string in a turbulent flow, considerations on a "dynamical temperature"

3,5 new printed pagesWe report on measurements of the transverse fluctuations of a string in a turbulent air jet flow. Harmonic modes are excited by the fluctuating drag force, at different wave-numbers. This simple mechanical probe makes it possible to measure excitations of the flow at specific scales, averaged over space and time: it is a scale-resolved, global measurement. We also measure the dissipation associated to the string motion, and we consider the ratio of the fluctuations over dissipation (FDR). In an exploratory approach, we investigate the concept of {\it effective temperature} defined through the FDR. We compare our observations with other definitions of temperature in turbulence. From the theory of Kolmogorov ($1941$), we derive the exponent $-11/3$ expected for the spectrum of the fluctuations. This simple model and our experimental results are in good agreement, over the range of wave-numbers, and Reynolds number accessible ($74000 \leq Re \leq 170000$)

Les Hmong et le tourisme ethnique à Sa Pa : entre modernité et micro-résistances

Depuis 1986, le Vietnam a connu un Renouveau économique (Đổi mới en Vietnamien), dont les conséquences politiques sont nombreuses. Cette ouverture au marché néo-libéral, inspirée par les mesures prises en Chine quelques années plus tôt, n’empêche toutefois pas le Parti Communiste Vietnamien, véritable tête du pays, de continuer à exercer sa gouvernementalité de manière autoritaire et socialiste. La République Socialiste du Vietnam est donc un État hybride, que les allégeances néolibérales poussent vers une modernisation aux accents occidentaux. Dans cette course au développement, le Vietnam fait face à un défi singulier : il doit composer avec un total de cinquante-quatre ethnies reconnues officiellement sur le territoire. Or, le pouvoir vietnamien sous tous ses aspects porte les couleurs de la majorité, les Kinh ou Viet. Afin d’apporter la modernité aux « petits frères » que sont les nationalités minoritaires, l’État Kinh organise l’ethnicité selon un principe général de préservation culturelle sélective. Les nationalités minoritaires peuvent alors arborer leurs identités singulières, tant qu’elles se présentent sous des aspects bénins et essentiellement esthétiques, dépourvues de tout danger pour les enjeux étatiques visant une modernité et une identité nationale unie. Ce mémoire tire ses racines d’une enquête ethnographique effectuée aux étés 2016 et 2017, auprès des représentants d’une de ces nationalités minoritaires : les Hmong vivant dans le district de Sa Pa, au Nord du Vietnam. Afin d’ancrer la recherche dans un cadre théorique pertinent, je tire mes réflexions des concepts de micro-résistance et d’infrapolitique développés par James Scott, et repris par Jean Michaud dans ses travaux sur les Hmong de Sa Pa. Grâce à ces notions, j’entends ici analyser comment certains discours produits par des Hmong participant au tourisme dans le district de Sa Pa peuvent être interprétés comme des exemples de micro-résistance, permettant éventuellement aux participant-es à la recherche de se construire une place dans ce contexte mouvementé, entre modernité et résistance.Since 1986, Vietnam has undergone an economic renovation (Đổi mới in Vietnamese), resulting in many political consequences. This opening to the neo-liberal market economy, inspired by decisions made in China a few years sooner, does not yet stop the Vietnamese Communist Party, as the true head of the country, from governing in an authoritarian and socialist manner. The Socialist Republic of Vietnam is thus a hybrid state, pushed towards a modernization process with Western afternotes, thanks to its neo-liberal allegiances. In this race for development, Vietnam faces a singular challenge : it must deal with a total of fifty-four official ethnicities living inside its borders. Yet, Vietnamese power is, in all its aspects, essentially related to the ethnic majority, namely the Kinh, or Viet. In order to bring modernity to the minority nationalities, considered as “little brothers”, the Kinh state then organizes ethnicity around a grand principle of selective cultural preservation. Minority nationalities can thus show their singular identities, provided they do so in a benign and essentially esthetic fashion, deprived of any potential danger for the state goals aiming at unified national identity and modernity. This thesis is based on an ethnographic investigation conducted throughout the summers of 2016 and 2017, among the people of one of these minority nationalities : the Hmong living in the Sa Pa district, in the North of Vietnam. In order to give this research a pertinent theoretical anchor, I draw my analysis from concepts such as micro-resistance and infrapolitics, devised by James Scott and utilized by Jean Michaud in his many works regarding the Hmong living in Sa Pa. Thanks to these notions, I analyse how certain transcripts produced by Hmong taking part in touristic activities in the Sa Pa district can be interpreted as examples of micro-resistance, enabling them to shape a singular place for their community in this rapidly evolving context, pulled between modernity and resistance

Comparison of meta-learners for estimating multi-valued treatment heterogeneous effects

Conditional Average Treatment Effects (CATE) estimation is one of the main challenges in causal inference with observational data. In addition to Machine Learning based-models, nonparametric estimators called meta-learners have been developed to estimate the CATE with the main advantage of not restraining the estimation to a specific supervised learning method. This task becomes, however, more complicated when the treatment is not binary as some limitations of the naive extensions emerge. This paper looks into meta-learners for estimating the heterogeneous effects of multi-valued treatments. We consider different meta-learners, and we carry out a theoretical analysis of their error upper bounds as functions of important parameters such as the number of treatment levels, showing that the naive extensions do not always provide satisfactory results. We introduce and discuss meta-learners that perform well as the number of treatments increases. We empirically confirm the strengths and weaknesses of those methods with synthetic and semi-synthetic datasets.Comment: 42 pages, 9 figures, to appear in ICML 2023 conferenc

Reference prior for Bayesian estimation of seismic fragility curves

One of the crucial quantities of probabilistic seismic risk assessment studies is the fragility curve, which represents the probability of failure of a mechanical structure conditional to a scalar measure derived from the seismic ground motion. Estimating such curves is a difficult task because for most structures of interest, few data are available, whether they come from complex numerical simulations or experimental campaigns. For this reason, a wide range of the methods of the literature rely on a parametric log-normal model. Bayesian approaches allow for efficient learning of the model parameters. However, for small data set sizes, the choice of the prior distribution has a non-negligible influence on the posterior distribution, and therefore on any resulting estimate. We propose a thorough study of this parametric Bayesian estimation problem when the data are binary (i.e. data indicate the state of the structure, failure or non-failure). Using the reference prior theory as a support, we suggest an objective approach for the prior choice to simulate a posteriori fragility curves. This approach leads to the Jeffreys prior and we prove that this prior depends only of the ground motion characteristics, making its calculation suitable for any equipment in an industrial installation subjected to the same seismic hazard. Our proposal is theoretically and numerically compared to those classically proposed in the literature by considering three different case studies. The results show the robustness and advantages of the Jeffreys prior in terms of regularization (no degenerate estimations) and stability (no outliers of the parameters) for fragility curves estimation

Socioeconomic agents as active matter in nonequilibrium Sakoda-Schelling models

How robust are socioeconomic agent-based models with respect to the details of the agents' decision rule? We tackle this question by considering an occupation model in the spirit of the Sakoda-Schelling model, historically introduced to shed light on segregation dynamics among human groups. For a large class of utility functions and decision rules, we pinpoint the nonequilibrium nature of the agent dynamics, while recovering the equilibrium-like phase separation phenomenology. Within the mean field approximation we show how the model can be mapped, to some extent, onto an active matter field description (Active Model B). Finally, we consider non-reciprocal interactions between two populations, and show how they can lead to non-steady macroscopic behavior. We believe our approach provides a unifying framework to further study geography-dependent agent-based models, notably paving the way for joint consideration of population and price dynamics within a field theoretic approach.Comment: 12 pages, 7 figure

Poitou-Charentes

L’invisibilité de façade des immigrés et le silence qui entoure leur mémoire en Poitou-Charentes pourrait laisser croire que la région n’a pas été concernée – ou très peu – par le fait migratoire. Or, certes moins importants que dans d’autres régions plus industrialisées de France, des flux migratoires ont bien été observés en région, comme l’attestent, notamment, l’importante présence portugaise à Cerizay ou encore, aujourd’hui, l’installation bienvenue, du fait de la chute démographique rurale, des Britanniques dans les cantons du sud de la Vienne, où ils constituent jusqu’à 10 % de la population cantonale

Fluorescent labeling in semi-solid medium for selection of mammalian cells secreting high-levels of recombinant proteins

<p>Abstract</p> <p>Background</p> <p>Despite the powerful impact in recent years of gene expression markers like the green fluorescent protein (GFP) to link the expression of recombinant protein for selection of high producers, there is a strong incentive to develop rapid and efficient methods for isolating mammalian cell clones secreting high levels of marker-free recombinant proteins. Recently, a method combining cell colony growth in methylcellulose-based medium with detection by a fluorescently labeled secondary antibody or antigen has shown promise for the selection of Chinese Hamster Ovary (CHO) cell lines secreting recombinant antibodies. Here we report an extension of this method referred to as fluorescent labeling in semi-solid medium (FLSSM) to detect recombinant proteins significantly smaller than antibodies, such as IGF-E5, a 25 kDa insulin-like growth factor derivative.</p> <p>Results</p> <p>CHO cell clones, expressing 300 μg/ml IGF-E5 in batch culture, were isolated more easily and quickly compared to the classic limiting dilution method. The intensity of the detected fluorescent signal was found to be proportional to the amount of IGF-E5 secreted, thus allowing the highest producers in the population to be identified and picked. CHO clones producing up to 9.5 μg/ml of Tissue-Plasminogen Activator (tPA, 67 kDa) were also generated using FLSSM. In addition, IGF-E5 high-producers were isolated from 293SF transfectants, showing that cell selection in semi-solid medium is not limited to CHO and lymphoid cells. The best positive clones were collected with a micromanipulator as well as with an automated colony picker, thus demonstrating the method's high throughput potential.</p> <p>Conclusion</p> <p>FLSSM allows rapid visualization of the high secretors from transfected pools prior to picking, thus eliminating the tedious task of screening a high number of cell isolates. Because of its rapidity and its simplicity, FLSSM is a versatile method for the screening of high producers for research and industry.</p

Efficacy of Diosmectite (Smecta)® in the Treatment of Acute Watery Diarrhoea in Adults: A Multicentre, Randomized, Double-Blind, Placebo-Controlled, Parallel Group Study

Background. Although diosmectite has demonstrated efficacy in the treatment of acute watery diarrhoea in children, its efficacy in adults still needs to be assessed. The objective of this study was therefore to assess the efficacy of diosmectite on the time to recovery in adults with acute diarrhoea. Methods. A total of 346 adults with at least three watery stools per day over a period of less than 48 hours were prospectively randomized to diosmectite (6 g tid) or placebo during four days. The primary endpoint was time to diarrhoea recovery. Results. In the intention-to-treat population, median time to recovery was 53.8 hours (range [3.7–167.3]) with diosmectite (n = 166) versus 69.0 hours [2.2–165.2] with placebo, (n = 163; P = .029), which corresponds to a difference of 15.2 hours. Diosmectite was well tolerated. Conclusion. Diosmectite at 6 g tid was well tolerated and reduced the time to recovery of acute watery diarrhoea episode in a clinically relevant manner