Buckling of Viscous Filaments of a Fluid under Compression Stresses

International audienceWe study the compression of viscous filaments at constant velocity. If slender enough, the filament bends, a viscous analogue of Euler elastic buckling. We measure the characteristic time of this viscous buckling and discuss the link with the elastic critical compression. We show that the analogy only holds in the limit of large capillary numbers. Otherwise capillarity has a stabilizing effect, which suppresses buckling

Remarques sur le breton parlé à Plaudren

Plaudren (Morbihan), commune rurale de 1 600 habitants située à 16 km au nord de Vannes, au bord des Landes de Lanvaux, se trouve à la frontière de la zone bretonnante. La pratique du breton y est aujourd'hui très faible. Le corpus dont je dispose est le résultat d'enregistrements réalisés auprès de plusieurs personnes de ma famille qui, pour la plupart, ont toujours vécu à Plaudren. Ce corpus comprend deux types d'entretiens : des « histoires de vie » auprès d'informateurs nés avant la Première Guerre mondiale, et des phrases à traduire, enquête réalisée auprès d'informateurs plus jeunes (nés dans les années 1920 et 1930). Il s’agit ici de relever quelques spécificités du parler de Plaudren, en relevant en particuliers : les conjugaisons et leur importance respective dans le parler de Plaudren, les formes du verbe être (utilisation de ema et bez), et la forme du verbe être à la 3e personne du présent de l'indicatif.Situated on the fringes of the Breton area, Plaudren (Morbihan) is a rural commune of 1,600 inhabitants located 16 km north of Vannes on the edge of the Landes de Lanvaux moorlands. Breton is used very little in Plaudren today. The corpus for the study comprised recordings of several members of my family, most of whom had lived their whole lives in Plaudren. It included two types of interviews: ‘life stories’ from the informants born before the First World War and translated sentences from the younger informants (born in the 1920s and 1930s). The aim was to identify some specific features of the Plaudren dialect, in particular: conjugations and their respective importance in the Plaudren dialect, forms of the verb ‘to be’ (use of ema and bez) and form of the verb ‘to be’ in the 3rd person present indicative

Trapping Leidenfrost Drops with Crenelations

International audienceDrops placed on very hot solids levitate on a cushion of their own vapor, as discovered by Leidenfrost. This confers to these drops a remarkable mobility, which makes problematic their control and manipulation. Here we show how crenelated surfaces can be used to increase the friction of Leidenfrost drops by a factor on the order of 100, making them decelerate and be trapped on centimetric distances instead of the usual metric ones. We measure and characterize the friction force as a function of the design of the crenelations

Frequency domain analysis of transmission zeroes on high-speed interconnects in the presence of an orthogonal metal grid underlayer

4 p.International audienceThis paper addresses high-speed interconnects in high density systems (Systems on Chip (SoC) in package (SiP) ...). These lines (of miscostrip or coplanar type) often have an underlayer of orthogonal metal grids which can affect transmission characteristics. We subsequently present a characterization through S-parameter measurements and electromagnetic simulations. Two kinds of grid are studied; grounded (CC) and floating grid (CO). In both cases, transmission zeroes appear. The position of these transmission zeroes in the frequency domain depends mainly on the grid length and, of course, on the grid charge CC or CO. In order to easily estimate it, we propose a simple equivalent circuit model which we validate by measurements and electromagnetic simulations. We then determine a set of expressions based on this model enabling us to analytically pinpoint the location transmission zero in the frequency domain, valid for any underlayer of orthogonal metal lines or grids

Méthode d'extraction fréquentielle de l'inductance de boucle pour la modélisation large bande des interconnexions de circuits numériques

4 pagesNational audienceDans le contexte des interconnexions de circuits numériques avancés, la modélisation de type RC actuelle n'est plus suffisamment précise face à l'augmentation des fréquences d'horloge, notamment en ce qui concerne les niveaux globaux. Les effets inductifs sont donc à prendre en compte et le concept de l'inductance de boucle semble être une solution intéressante pour ne pas complexifier de façon excessive les modèles. Nous décrivons dans ce papier une méthode d'extraction fréquentielle de l'inductance de boucle permettant de prendre en compte les effets de proximité dus à l'augmentation de la fréquence. Nous proposons, de plus, un modèle compact que nous validons par une analyse temporelle

Simulation, Measurement and Modeling of Orthogonal On-Chip Interconnects

International audienceThis paper explains the appearance of resonant frequency due to underlayer orthogonal metal grid in microstrip line structures. In the context of global interconnects, this resonant frequency may lead to noise and has to be estimate. A model, which allows one to approximate this resonant frequency, is validated by measurement

Nouvelles interconnexions globales à haut débit pour la réalisation de microsystèmes communicants de type SIP.

4 pagesNational audienceLes microsystèmes intégrés sur puces (SoC) ou en boîtier (SiP) sont actuellement en plein essor et nécessitent le développement de nouvelles structures d'interconnexions reliant les différents blocs fonctionnels entre eux. Nous proposons dans ce papier l'étude du concept d'interconnexion RF par couplage capacitif qui est une solution intéressante pour remplacer les interconnexions classiques. Dans un premier temps nous décrivons le principe de cette technique et montrons à l'aide de simulations circuits de type ADS, la faisabilité de ce concept. Nous présentons ensuite la caractérisation d'un canal de type microruban, réalisée sous HFSS ainsi que son comportement dans le domaine temporel. I. Introductio

Profiling the landscape of transcription, chromatin accessibility and chromosome conformation of cattle, pig, chicken and goat genomes [FAANG pilot project]

Functional annotation of livestock genomes is a critical and obvious next step to derive maximum benefit for agriculture, animal science, animal welfare and human health. The aim of the Fr-AgENCODE project is to generate multi-species functional genome annotations by applying high-throughput molecular assays on three target tissues/cells relevant to the study of immune and metabolic traits. An extensive collection of stored samples from other tissues is available for further use (FAANG Biosamples ‘FR-AGENCODE’). From each of two males and two females per species (pig, cattle, goat, chicken), strand-oriented RNA-seq and chromatin accessibility ATAC-seq assays were performed on liver tissue and on two T-cell types (CD3+CD4+&CD3+CD8+) sorted from blood (mammals) or spleen (chicken). Chromosome Conformation Capture (in situ Hi-C) was also carried out on liver. Sequencing reads from the 3 assays were processed using standard processing pipelines. While most (50–70%) RNA-seq reads mapped to annotated exons, thousands of novel transcripts and genes were found, including extensions of annotated protein-coding genes and new lncRNAs (see abstract #69857). Consistency of ATAC-seq results was confirmed by the significant proportion of called peaks in promoter regions (36–66%) and by the specific accumulation pattern of peaks around gene starts (TSS) v. gene ends (TTS). Principal Component Analyses for RNA-seq (based on quantified gene expression) and ATAC-seq (based on quantified chromatin accessibility) highlighted clusters characterised by cell type and sex in all species. From Hi-C data, we generated 40kb-resolution interaction maps, profiled a genome-wide Directionality Index and identified from 4,100 (chicken) to 12,100 (pig) topologically-associating do- mains (TADs). Correlations were reported between RNA-seq and ATAC-seq results (see abstract #71581). In summary, we present here an overview of the first multi-species and -tissue annotations of chromatin accessibility and genome architecture related to gene expression for farm animals

Temporal changes in total and size-fractioned chlorophyll-a in surface waters of three provinces in the Atlantic Ocean (September to November) between 2003 and 2010

Phytoplankton total chlorophyll concentration (TCHLa) and phytoplankton size structure are two important ecological indicators in biological oceanography. Using high performance liquid chromatography (HPLC) pigment data, collected from surface waters along the Atlantic Meridional Transect (AMT), we examine temporal changes in TCHLa and phytoplankton size class (PSC: micro-, nano- and pico-phytoplankton) between 2003 and 2010 (September to November cruises only), in three ecological provinces of the Atlantic Ocean. The HPLC data indicate no significant change in TCHLa in northern and equatorial provinces, and an increase in the southern province. These changes were not significantly different to changes in TCHLa derived using satellite ocean-colour data over the same study period. Despite no change in AMT TCHLa in northern and equatorial provinces, significant differences in PSC were observed, related to changes in key diagnostic pigments (fucoxanthin, peridinin, 19’-hexanoyloxyfucoxanthin and zeaxanthin), with an increase in small cells (nano- and pico-phytoplankton) and a decrease in larger cells (micro-phytoplankton). When fitting a three-component model of phytoplankton size structure ̶ designed to quantify the relationship between PSC and TCHLa ̶ to each AMT cruise, model parameters varied over the study period. Changes in the relationship between PSC and TCHLa have wide implications in ecology and marine biogeochemistry, and provide key information for the development and use of empirical ocean-colour algorithms. Results illustrate the importance of maintaining a time-series of in-situ observations in remote regions of the ocean, such as that acquired in the AMT programme

Estimation of the prevalence of lymphoedema/chronic oedema in acute hospital in-patients

Background: To estimate the prevalence of lymphoedema/chronic oedema and wounds in acute hospital in-patients in 5 different countries. Method: A point-prevalence study was carried out during working day periods in six general hospitals in four countries (Denmark, France, United Kingdom, Australia) and one hospital oncology in-patient unit in one other country (Ireland). The study used validated clinical tools for the assessment and collection of data. Data were collected by expert clinicians through interviews and physical examination of the patients present in the wards. Results: A total of 1905 patients could be included and investigated among the 3041 total bed occupancy in the seven hospitals. Lymphoedema/chronic oedema was present in 723 of them (38%). Main risk factors associated with chronic oedema were age, morbid obesity and heart failure as well as chair bound immobility and neurological deficiency. History of cellulitis was frequent in patients with chronic oedema and wounds (24.8%), chronic oedema alone (14.1%) as compared to the 1.5% prevalence in patients without chronic oedema. Conclusion: Lymphoedema/chronic oedema is very frequent in patients hospitalized in hospital acute wards. It is strongly associated with obesity, venous insufficiency and heart failure. Our results strongly suggest a hidden health care burden and cost linked to chronic oedema independently of chronic wounds