Enhanced and reduced transmission of acoustic waves with bubble meta-screens

We present a class of sonic meta-screens for manipulating air-borne acoustic waves at ultrasonic or audible frequencies. Our screens consist of periodic arrangements of air bubbles in water or possibly embedded in a soft elastic matrix. They can be used for soundproofing, but also for exalting transmission at an air/water interface or even to achieve enhanced absorption

Modèle de la réponse temporelle de la dispersion chromatique

National audienceNous proposons un modèle numérique de fonction de transfert en z d’un milieu dispersif (fibre, milieux gazeux dense) pour l’enveloppe temporelle (modulations de phase et d’amplitude) de porteuses optiques ou hyperfréquence. Les modélisations existantes (FFT, filtre à réponse impulsionnelle finie, transformée bilinéaire) sont insuffisantes pour des signaux contenant des bruits colorés ou même ne reproduisent pas la dispersion voulue. À partir de développements de Padé des fonctions exponentielle et logarithme, nous obtenons une fonction de transfert sous forme de fraction rationnelle. Les pôles instables sont traités par retournement temporel. Le modèle est étudié pour un objectif de modulation en quadrature à haut débit sur de longues fibres, par exemple plusieurs centaines de mètres de fibre SMF à 2*28 Gb/s en QAM

Towards the 2017 French election: Socialist and Republican nominees from the selection to the presidential election

In France, primaries have become an important part of French party system. Recently, the process, used by different parties, has been opened also to sympathisers. Indeed, both the Socialist Party and the Republicans organised primaries in the 2017 presidential elections. This can be analysed as an expected step to address problems such as leadership and representativeness. In addition, this process is also in line with the personalisation that has become a characteristic of the Fifth Republic. However, after the collapse of the main parties in the last elections, the primary system seems to have entered in a crisis time. For this reason, this article will attempt to analyse the introduction of primaries in France with a particular attention on the last presidential election focusing on the similarities, differences, and effects in these two open selections

COUPLAGE NON LINÉAIRE PHASE-AMPLITUDE DANS LES RÉSONATEURS

National audienc

A commuting network model: going to the bulk

The influence of commuting in socio-economic dynamics increases constantly. Analysing and modelling the networks formed by commuters to help decision-making regarding the land-use has become crucial. This paper presents a simple spatial interaction simulated model with only one parameter. The proposed algorithm considers each individual who wants to commute, starting from their living place to all their workplaces. It decides where the location of the workplace following the classical rule inspired from the gravity law consisting in a compromise between the job offers and the distance to the jobs. The further away the job offer is, the more important it must be in order to be considered. Inversely, only the quantity of offers is important for the decision when these offers are close. The paper also presents a comparative analysis of the structure of the commuting networks of the four European regions to which we apply our model. The model is calibrated and validated on these regions. Results from the analysis shows that the model is very efficient in reproducing most of the statistical properties of the network given by the data sources.Comment: submitted to JASS

The analog data assimilation

In light of growing interest in data-driven methods for oceanic, atmospheric, and climate sciences, this work focuses on the field of data assimilation and presents the analog data assimilation (AnDA). The proposed framework produces a reconstruction of the system dynamics in a fully data-driven manner where no explicit knowledge of the dynamical model is required. Instead, a representative catalog of trajectories of the system is assumed to be available. Based on this catalog, the analog data assimilation combines the nonparametric sampling of the dynamics using analog forecasting methods with ensemble-based assimilation techniques. This study explores different analog forecasting strategies and derives both ensemble Kalman and particle filtering versions of the proposed analog data assimilation approach. Numerical experiments are examined for two chaotic dynamical systems: the Lorenz-63 and Lorenz-96 systems. The performance of the analog data assimilation is discussed with respect to classical model-driven assimilation. A Matlab toolbox and Python library of the AnDA are provided to help further research building upon the present findings.Fil: Lguensat, Redouane. Université Bretagne Loire; FranciaFil: Tandeo, Pierre. Université Bretagne Loire; FranciaFil: Ailliot, Pierre. University of Western Brittany. Laboratoire de Mathématiques de Bretagne Atlantique; FranciaFil: Pulido, Manuel Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Modelado e Innovación Tecnológica. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Modelado e Innovación Tecnológica; ArgentinaFil: Fablet, Ronan. Université Bretagne Loire; Franci

Participatory Plant Breeding for Organic Farming in France, the cauliflower experience at the PAIS

The availability of organic seeds is a great problem for organic farmers. The private sector of plant breeding meets difficulties to answer to the organic farming (OF) demand, characterized by small quantities and a great diversity of criteria and by breeding methods which respect the natural species characteristics (see IFOAM Draft Standard on organic seeds and plant breeding). So, the organic sector is organizing breeding and seed production by itself In France, since 2001, a Brittany regional organic umbrella (IBB, Inter Bio Bretagne), and some researchers from the national institute for agronomical research (INRA) have initiated a breeding program for organic production and a participatory plant breeding (PPB) program for organic cabbages and cauliflowers in Brittany, from the evaluation of genetic resources of several European gene Banks. In the PPB, the farmers are taking in charge breeding and seed production of open pollinated varieties. Several types were kept and bred, depending on the way of production and commercialization for each farmer. In the northern Brittany, farmers have not forgotten the traditional production of cauliflower seeds. PAIS, the agrobiological experimental station of IBB on the organic site of an agricultural school (Suscinio, Morlaix), is the meeting point for all the involved actors (farmers, traders, trainers, researchers…). There, the farmers and traders can find technical and scientific information, and they can share their experiences from the plant selection to seed production. Today, other French PPB initiatives involve several species and organic farmers groups, to promote biodiversity and a best adaptation to a local production: durum wheat in the Mediterranean area, bread wheat with the “paysan-boulangers”, maize and sunflower in the South-West of the country, tomato in the South-East, radishes, parsnip and summer cauliflower, in Pays de Loire. From these experiences, the PPB for organic farming consists in the constitution of the organic farmers group with the creation of exchange space for researchers and others organic actors, the definition of the priority in matters of crops, the discovering and selection of genetic resources in the farmers fields, the exchange of experiences and genetic resources through formal and informal, regional, national or international, farmer and organic professional meetings (accompanied by researchers and often enlarged to gardeners and trainers). The seed distribution has been depending on the French legislative evolution. By nature, the varieties issued from PPB could not fill the DUS (Distinction, Uniformity, Stability) characteristics for registration. And mainly, by ethics, the organic way of development should enhance the ancestral link between the plant and the farmers, link which needs exchanges to allow the evolution of the crops and the conservation of a living biodiversity

Charge Particle Angular Correlations from Leading Photons at RHIC

We report on the observation of jet-like azimuthal and pseudorapidity correlations between the highest $p_T$ photon (leading photon) and charged hadrons produced in both p+p and Au+Au collisions at $\sqrt{s_{NN}} = 200$ GeV.Comment: 4 pages, 3 figures. Talk given at Quark Matter 2002 (QM 2002), Nantes, Bretagne, France, 18-24 Jul 200

Development and validation of a simplified method to quantify gaseous emissions from cattle buildings

Obtaining representative gaseous emission factors from livestock production requires measurement methods adapted to a high number and a great diversity of livestock systems, including naturally ventilated buildings. The objective of this study is to propose such a method for cattle houses, based on livestock-related data (e.g., feeds, production, effluents) and intermittent measurements of gas concentrations (H2O, CO2, NH3, CH4, and N2O), temperature, and relative humidity. These data were used to estimate gas-concentration gradients and mass-balance deficits of C, N, and H2O). Emissions were calculated using the ratios of gas-concentration gradients. For quality control, the results were validated with water-budget observations and simulation model predictions of CH4 and CO2 emissions from cattle. During summer 2007, measurements were performed in seven types of barns commonly found in France. For buildings with slurry evacuated twice a day, good agreement was found between CO2 and CH4 emissions estimated with the simplified method and those predicted from models of cattle emission. For these buildings the observed emissions were homogeneous. For buildings with deep litter, observed emissions of CH4 and CO2 were higher than the predicted emissions. The difference indicates that a part of those gases was emitted by manure. Additional data and models should be used to improve this method for deep-litter systems. Data analysis continues to evaluate the method during winter conditions and in poultry or swine farms. (Résumé d'auteur