Design study and first performance simulation of the ELT/MICADO focal plane coronagraphs

In this paper, we present the design and the expected performance of the classical Lyot coronagraph for the high contrast imaging modes of the wide-field imager MICADO. MICADO is a near-IR camera for the Extremely Large Telescope (ELT, previously E-ELT), with wide-field, spectroscopic and coronagraphic capabilities. MICADO is one of the first-light instruments selected by the ESO. Optimized to work with a multi-conjugate adaptive optics corrections provided by the MOARY module, it will also come with a SCAO correction with a high-level, on-axis correction, making use of the M4 adaptive mirror of the telescope. After presenting the context of the high contrast imaging modes in MICADO, we describe the selection process for the focal plane masks and Lyot stop. We will also show results obtained in realistic conditions, taking into account AO residuals, atmospheric refraction, noise sources and simulating observations in angular differential imaging (ADI) mode. Based on SPHERE on-sky results, we will discuss the achievable gain in contrast and angular separation provided by MICADO over the current instruments on 10-m class telescopes, in particular for imaging young giant planets at very short separations around nearby stars as well as planets on wider orbits around more distant stars in young stellar associations.Comment: 10 pages, 5 figures, AO4ELT 5 conference proceedin

Influence of Pt particle size and reaction phase on the photocatalytic performances of ultradispersed Pt/TiO2 catalysts for hydrogen evolution

Pt/TiO2 photocatalysts were prepared by incipient wetness impregnation followed by oxidative and/or reductive thermal treatments. By varying the TiO2 form (commercial P25 and P90, and homemade shape-controlled), the Pt loading (0.2-1 wt% Pt) and the treatment temperature (200-600°C), it has been possible to tune the Pt cluster size. An increase in the ethanol dehydrogenation rate under ultraviolet irradiation as the Pt cluster average diameter decreases from 17 to 9 Å is suggested by our data. Whereas pre-reduction in H2 leads to Pt clusters, pre-calcination in air leads to atomically dispersed cationic Pt species. The former are more active and stable than the latter. This conclusion is valid both in gas- and liquid-phase reaction conditions for given TiO2 type and Pt loading. The activity results are consistent with a recent theoretical work showing that 1 nm is an optimal Pt cluster size for favoring both photoelectron transfer from TiO2 to Pt and hydrogen coupling on Pt. The best catalytic performance is obtained in gas phase for pre-reduced 0.2 wt% Pt/TiO2-P90, with an H2 production rate of 170 mmol h-1 gcat-1.Postprint (author's final draft

Evaluation using latent class models of the diagnostic performances of three ELISA tests commercialized for the serological diagnosis of <i>Coxiella burnetii</i> infection in domestic ruminants

International audienceELISA methods are the diagnostic tools recommended for the serological diagnosis of Coxiella burnetii infection in ruminants but their respective diagnostic performances are difficult to assess because of the absence of a gold standard. This study focused on three commercial ELISA tests with the following objectives (1) assess their sensitivity and specificity in sheep, goats and cattle, (2) assess the between-and within-herd seroprevalence distribution in these species, accounting for diagnostic errors, and (3) estimate optimal sample sizes considering sensitivity and specificity at herd level. We comparatively tested 1413 cattle, 1474 goat and 1432 sheep serum samples collected in France. We analyzed the cross-classified test results with a hierarchical zero-inflated beta-binomial latent class model considering each herd as a population and conditional dependence as a fixed effect. Potential biases and coverage probabilities of the model were assessed by simulation. Conditional dependence for truly seropositive animals was high in all species for two of the three ELISA methods. Specificity estimates were high, ranging from 94.8% [92.1; 97.8] to 99.2% [98.5; 99.7], whereas sensitivity estimates were generally low, ranging from 39.3 [30.7; 47.0] to 90.5% [83.3; 93.8]. Betweenand within-herd seroprevalence estimates varied greatly among geographic areas and herds. Overall, goats showed higher within-herd seroprevalence levels than sheep and cattle. The optimal sample size maximizing both herd sensitivity and herd specificity varied from 3 to at least 20 animals depending on the test and ruminant species. This study provides better interpretation of three widely used commercial ELISA tests and will make it possible to optimize their implementation in future studies. The methodology developed may likewise be applied to other human or animal diseases

Genetic Structure of Human A/H1N1 and A/H3N2 Influenza Virus on Corsica Island: Phylogenetic Analysis and Vaccine Strain Match, 2006–2010

Background: The aim of this study was to analyse the genetic patterns of Hemagglutinin (HA) genes of influenza A strains circulating on Corsica Island during the 2006-2009 epidemic seasons and the 2009-2010 pandemic season. [br/] Methods: Nasopharyngeal samples from 371 patients with influenza-like illness (ILI) were collected by General Practitioners (GPs) of the Sentinelles Network through a randomised selection routine. [br/] Results: Phylogenetic analysis of HA revealed that A/H3N2 strains circulating on Corsica were closely related to the WHO recommended vaccine strains in each analyzed season (2006-2007 to 2008-2009). Seasonal Corsican influenza A/H1N1 isolated during the 2007-2008 season had drifted towards the A/Brisbane/59/2007 lineage, the A/H1N1 vaccine strain for the 2008-2009 season. The A/H1N1 2009 (A/H1N1pdm) strains isolated on Corsica Island were characterized by the S220T mutation specific to clade 7 isolates. It should be noted that Corsican isolates formed a separate sub-clade of clade 7 as a consequence of the presence of the fixed substitution D222E. The percentages of the perfect match vaccine efficacy, estimated by using the p(epitope) model, against influenza viruses circulating on Corsica Island varied substantially across the four seasons analyzed, and tend to be highest for A/H1N1 compared with A/H3N2 vaccines, suggesting that cross-immunity seems to be stronger for the H1 HA gene. [br/] Conclusion: The molecular analysis of the HA gene of influenza viruses that circulated on Corsica Island between 2006-2010 showed for each season the presence of a dominant lineage characterized by at least one fixed mutation. The A/H3N2 and A/H1N1pdm isolates were characterized by multiples fixation at antigenic sites. The fixation of specific mutations at each outbreak could be explained by the combination of a neutral phenomenon and a founder effect, favoring the presence of a dominant lineage in a closed environment such as Corsica Island

Field Effectiveness of Pandemic and 2009-2010 Seasonal Vaccines against 2009-2010 A(H1N1) Influenza: Estimations from Surveillance Data in France

BACKGROUND: In this study, we assess how effective pandemic and trivalent 2009-2010 seasonal vaccines were in preventing influenza-like illness (ILI) during the 2009 A(H1N1) pandemic in France. We also compare vaccine effectiveness against ILI versus laboratory-confirmed pandemic A(H1N1) influenza, and assess the possible bias caused by using non-specific endpoints and observational data. METHODOLOGY AND PRINCIPAL FINDINGS: We estimated vaccine effectiveness by using the following formula: VE  =  (PPV-PCV)/(PPV(1-PCV)) × 100%, where PPV is the proportion vaccinated in the population and PCV the proportion of vaccinated influenza cases. People were considered vaccinated three weeks after receiving a dose of vaccine. ILI and pandemic A(H1N1) laboratory-confirmed cases were obtained from two surveillance networks of general practitioners. During the epidemic, 99.7% of influenza isolates were pandemic A(H1N1). Pandemic and seasonal vaccine uptakes in the population were obtained from the National Health Insurance database and by telephonic surveys, respectively. Effectiveness estimates were adjusted by age and week. The presence of residual biases was explored by calculating vaccine effectiveness after the influenza period. The effectiveness of pandemic vaccines in preventing ILI was 52% (95% confidence interval: 30-69) during the pandemic and 33% (4-55) after. It was 86% (56-98) against confirmed influenza. The effectiveness of seasonal vaccines against ILI was 61% (56-66) during the pandemic and 19% (-10-41) after. It was 60% (41-74) against confirmed influenza. CONCLUSIONS: The effectiveness of pandemic vaccines in preventing confirmed pandemic A(H1N1) influenza on the field was high, consistently with published findings. It was significantly lower against ILI. This is unsurprising since not all ILI cases are caused by influenza. Trivalent 2009-2010 seasonal vaccines had a statistically significant effectiveness in preventing ILI and confirmed pandemic influenza, but were not better in preventing confirmed pandemic influenza than in preventing ILI. This lack of difference might be indicative of selection bias

Observations of the Florida and Yucatan Currents from a Caribbean Cruise Ship

Abstract The Yucatan and Florida Currents represent the majority of the warm-water return path of the global thermohaline circulation through the tropical/subtropical North Atlantic Ocean. Their transports are quantified and compared by analyzing velocity data collected aboard the cruise ship Explorer of the Seas. From 157 crossings between May 2001 and May 2006, the mean transport of the Florida Current at 26°N was estimated to be 30.8 ± 3.2 Sv (1 Sv ≡ 106 m3 s−1), with seasonal amplitude of 2.9 Sv. Upstream, the Yucatan Current was estimated from 90 crossings to be 30.3 ± 5 Sv, with seasonal amplitude of 2.7 Sv. These two currents are shown to be linked at seasonal time scales. Hence, contrary to former results, it was found that transports through the Florida Straits and the Yucatan Channel are similar, with the implication that only small inflows occur through minor channels between them

On the seasonal variability of the currents in the Straits of Florida and Yucatan Channel

Seasonal variability in the major passages of the Caribbean are investigated using 5 years of wind and current observations (Explorer of the Seas), combined with a 3 year 1/12° simulation. Seasonal fluctuations in the Florida and Yucatan passages are both characterized by semiannual cycles with transport maxima in summer and winter and minima in spring and fall. In the Straits of Florida, seasonal variability is associated with surface‐intensified fluctuations of the Florida Current and can be largely explained by along‐channel winds and wind stress curl over the Atlantic Ocean. In the Yucatan Channel, seasonal variability is more barotropic and does not covary with wind forcing but rather is associated with fluctuations of an anticyclonic recirculation to the south of the channel. Upstream, the seasonality in the Grenada Passage also covaries with seasonality in the Yucatan and Florida passages, although the Grenada Passage carries only a small fraction of the total inflow to the Caribbean. Recent in situ estimates of the mean transport in the Yucatan Channel differ by 7 Sv (30.5 Sv, Explorer of the Seas; 23.1 Sv, CANEK). An assessment of sampling errors, biases, and interannual variability seem to account for no more than 2 Sv, leaving no satisfactory explanation for the difference. In Explorer of the Seas data, flows in the Straits of Florida and Yucatan Channel display similar vertical shear structure, while CANEK data exhibit significantly lower shears in the upper 500 m, which account for all the transport difference. Key Points Transports in the Florida and Yucatan passages have similar seasonal cycles Seasonality in Florida correlates with local winds Seasonality in Yucatan correlates with an anticyclonic gyre south of the channe

Closing the transport budget of the Florida Straits

Closing the mean mass budget of the Florida Straits is fundamental to understanding the source waters of the Gulf Stream and for constraining ocean simulations and forecasts in a region of complex topography. Existing transport time series of the inflow through Yucatan Channel and the outflow at 27°N yield a 9 Sv difference in the mean, which cannot be reconciled by the two minor inflows between. Here we present a synthesis of transport estimates from throughout the Florida Straits, using velocity data collected aboard the cruise ship Explorer of the Seas. Our transports form a consistent mass budget and conform with the northern outflow from the Straits of 32.1 ± 3.3 Sv, as measured continuously by cable. In particular, we find an average of 30.0 ± 5.3 Sv for the inflow to southern Florida Straits and estimate that Old Bahama Channel contributes less than an additional 2 Sv. Key Points The mean inflow in the southern Florida Straits is estimated at 30.0 ± 5.3 Sv The mean transports are consistent from Yucatan Channel to North Florida OBC inflow is less than 2 Sv with eastward flow on top and westward flow belo

Recent developments impacting the sea ice in the Mercator Océan global ¼° configuration

International audienc

Le rôle majeur du régime de Vichy dans l’encadrement des professions de santé

National audienceL'objet de ce colloque pluridisciplinaire est d'évaluer, 70 ans après l'ordonnance du 9 août 1944 relative au rétablissement de la légalité républicaine, « l'héritage juridique » du gouvernement de Vichy, c'est-à-dire les institutions, pratiques et législations qui, demeurant à ce jour, restent empreintes de l'esprit initial de Vichy.Les communications tenteront d'exposer la manière et les raisons qui ont pu permettre au régime de Vichy de se greffer dans un corps républicain, et comment, à la Libération, ont été perpétuées les mesures, les pratiques jugées compatibles avec cet idéal, conservées parfois, sans guère d'adaptation