Tests of Sapphire Crystals Produced with Different Growth Processes for Ultra-stable Microwave Oscillators

We present the characterization of 8-12 GHz whispering gallery mode resonators machined in high-quality sapphire crystals elaborated with different growth techniques. These microwave resonators are intended to constitute the reference frequency of ultra-stable Cryogenic Sapphire Oscillators. We conducted systematic tests near 4 K on these crystals to determine the unloaded Q-factor and the turnover temperature for whispering gallery modes in the 8-12 GHz frequency range. These characterizations show that high quality sapphire crystals elaborated with the Heat Exchange or the Kyropoulos growth technique are both suitable to meet a fractional frequency stability better than 1x10-15 for 1 s to 10.000 s integration times.Comment: 7 figure

Présentation de la Maquette Retraites MARS-2003

This paper describes the model MARS, which is the shared property of the DP and the DSS. Currently, MARS aims at planning the general evolution of the first pillar pension scheme for private sector wage-earners, based on macroeconomic and demographic data. It allows to evaluate the impact of changing the parameters used when calculating one’s annuities, or changing general hypotheses. The model provides results which deal with the dynamics of the average annuity and the financial sustainability of the pension scheme. MARS relies on a macroeconomic approach and aims at forecasting the life cycle of average individuals representing their generation. In concrete terms, each generation is represented by two agents (a man and a woman), whose behaviour is supposed to match the average economic and demographic characteristics of their peers (as far as fertility, activity and employment are concerned). In addition, another source of heterogeneity is acknowledged in the model concerning the retirement age, the distribution of which is determined endogenously. Then the evolution of the representative annuity, calculated on the basis of these data, is considered to reflect the dynamics of the average annuity – and at this stage, sustainability indicators for the pension scheme can be inferred. First, the document introduces the demographic and macroeconomic framework of the model, which basically relies on the population and labour force projections of the INSEE, and takes the Conseil d’Orientation des Retraites scenario as a benchmark for the evolution of real wages and unemployment. The making of the retirement decision is a key feature of the model : it is assumed that men will retire when reaching entitlement to the full rate, and that the male and female distributions of retirement ages will match from the 1970 generation onwards. On the basis of these hypotheses, the average pension and the financing requirement of the pension scheme can be evaluated. As an illustration, the results of two variants are displayed: one deals with the impact of the lengthening of the contribution period which results from the August 2003 Act, the other one shows the sensitiveness of the results to alternative demographic scenarios. We conclude about the weaknesses of the model, which is based on the lifecycle of average individuals, and the flaws associated to a macroeconomic approach, versus a dynamic microsimulation one. Besides, MARS should encounter new limits, due to non-linear effects and deeper uncertainty associated to changes in the method used to calculate pensions after the 2003 reform. This paper is written in French.long term forecast, modeling of pay as you go pension schemes

Invasion fronts with variable motility: phenotype selection, spatial sorting and wave acceleration

Invasion fronts in ecology are well studied but very few mathematical results concern the case with variable motility (possibly due to mutations). Based on an apparently simple reaction-diffusion equation, we explain the observed phenomena of front acceleration (when the motility is unbounded) as well as other quantitative results, such as the selection of the most motile individuals (when the motility is bounded). The key argument for the construction and analysis of traveling fronts is the derivation of the dispersion relation linking the speed of the wave and the spatial decay. When the motility is unbounded we show that the position of the front scales as $t^{3/2}$. When the mutation rate is low we show that the canonical equation for the dynamics of the fittest trait should be stated as a PDE in our context. It turns out to be a type of Burgers equation with source term.Comment: 7 page

Gemini Frontier Fields: Wide-field Adaptive Optics KsK_s-band Imaging of the Galaxy Clusters MACS J0416.1-2403 and Abell 2744

We have observed two of the six Frontier Fields galaxy clusters, MACS J0416.1-2403 and Abell 2744, using the Gemini Multi-Conjugate Adaptive Optics System (GeMS) and the Gemini South Adaptive Optics Imager (GSAOI). With 0.08"-0.10" FWHM our data are nearly diffraction-limited over a 100"x100" wide area. GeMS/GSAOI complements the Hubble Space Telescope (HST) redwards of 1.6microns with twice the angular resolution. We reach a 5 sigma depth of Ks = 25.6 mag (AB) for compact sources. In this paper we describe the observations, the data processing and the initial public data release. We provide fully calibrated, co-added images matching the native GSAOI pixel scale as well as the larger plate scales of the HST release, adding to the legacy value of the Frontier Fields. Our work demonstrates that even for fields at high galactic latitude, where natural guide stars are rare, current multi-conjugated adaptive optics technology at 8m-telescopes has opened a new window on the distant Universe. Observations of a third Frontier Field, Abell 370, are planned.Comment: Accepted for publication in ApJS; significantly revised compared to the first submissio

Renormalization constants for Nf=2+1+1N_{\rm f}=2+1+1 twisted mass QCD

We summarize recent non-perturbative results obtained for the renormalization constants computed in the RI'-MOM scheme for $N_{\rm f}=2+1+1$ twisted mass QCD. Our implementation employs the Iwasaki gauge action and four dynamical degenerate twisted mass fermions. Renormalization constants for scalar, pseudo-scalar, vector and axial operators, as well as the quark propagator renormalization, are computed at three different values of the lattice spacing, two different volumes and several values of the twisted mass. Our method allows for a precise cross-check of the running, because of the particular proper treatment of the hypercubic artifacts. Preliminary results for twist-2 operators are also presented

When the human viral infectome and diseasome networks collide: towards a systems biology platform for the aetiology of human diseases

<p>Abstract</p> <p>Background</p> <p>Comprehensive understanding of molecular mechanisms underlying viral infection is a major challenge towards the discovery of new antiviral drugs and susceptibility factors of human diseases. New advances in the field are expected from systems-level modelling and integration of the incessant torrent of high-throughput "-omics" data.</p> <p>Results</p> <p>Here, we describe the Human Infectome protein interaction Network, a novel systems virology model of a virtual virus-infected human cell concerning 110 viruses. This <it>in silico </it>model was applied to comprehensively explore the molecular relationships between viruses and their associated diseases. This was done by merging virus-host and host-host physical protein-protein interactomes with the set of genes essential for viral replication and involved in human genetic diseases. This systems-level approach provides strong evidence that viral proteomes target a wide range of functional and inter-connected modules of proteins as well as highly central and bridging proteins within the human interactome. The high centrality of targeted proteins was correlated to their essentiality for viruses' lifecycle, using functional genomic RNAi data. A stealth-attack of viruses on proteins bridging cellular functions was demonstrated by simulation of cellular network perturbations, a property that could be essential in the molecular aetiology of some human diseases. Networking the Human Infectome and Diseasome unravels the connectivity of viruses to a wide range of diseases and profiled molecular basis of Hepatitis C Virus-induced diseases as well as 38 new candidate genetic predisposition factors involved in type 1 <it>diabetes mellitus</it>.</p> <p>Conclusions</p> <p>The Human Infectome and Diseasome Networks described here provide a unique gateway towards the comprehensive modelling and analysis of the systems level properties associated to viral infection as well as candidate genes potentially involved in the molecular aetiology of human diseases.</p

Trait-anxiety dependence of movement time performance in a bimodal choice task in subjects exposed to moderate anxiogenic conditions

International audienceRecent studies have provided insight into the interdependence between state-anxiety, trait-anxiety and motor performances. In the present study, we investigated in very low trait-anxiety (VLTA) and normal trait-anxiety (NTA) subjects, the effects of moderate state-anxiety induced by the video-recorded Stroop color word interference test, on reaction time and movement time in bimodal choice response time task providing either visual or auditory modality. We found that in anxiogenic condition, movement time performances were improved in visual modality in NTA subjects, and in auditory modality in VLTA subjects. Our results show that depending on their trait-anxiety level, individuals exposed to anxiogenic condition would allocate attentional resources towards a specific relevant modality. Such attentional resources would influence movement time, but not reaction time