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As part of the evaluation of the French plan for the elimination of measles and rubella, we conducted a seroprevalence survey in 2013, aimed at updating seroprevalence data for people 18–32 years old. A secondary objective was to estimate measles incidence in this population during the 2009–2011 outbreak, and thus estimate the exhaustiveness of measles mandatory reporting. We used a cross-sectional survey design, targeting blood donors 18–32 years old, living in France since 2009, who came to give blood in a blood collecting site. We included 4647 people in metropolitan France, 806 people in Réunion Island and 496 in the French Caribbean. A further 3942 individuals were interviewed in the south-east region of metropolitan France to estimate the exhaustiveness of measles mandatory reporting. One of the main findings of this survey is that the proportion of people 18–32 years old susceptible to both measles and rubella infections remained high in France in 2013, 9.2% and 5.4%, respectively, in metropolitan France, even after the promotion campaigns about vaccination catch-up during and following the major measles epidemic in 2009–2011. Applying our results to French census data would suggest that around 1 million people aged 18–32 years old are currently susceptible to measles in France, despite this age group being one of the vaccination targets of the national measles elimination plan. Another important finding is that only an estimated 45% of the true number of cases in this age group was actually notified, despite notification being mandatory.
Longitude-coordinated high-precision photometry has been obtained a few weeks before the beginning of a strong Be and shell phase (1988) in HR 8762 (o And). The star showed variations of a few millimagnitudes in amplitude; i.e., just over the detection threshold. The classical 1.57-day double-wave period is still detected, showing that it probably never fades out completely, whatever the phase of the star. These variations can be interpreted as normal photospheric activity in a regular rotating B star. Although the variations of HR 8762 during our campaign were quite small, we could detect their amplitudes at a level of a few mmag.
We still have to check whether they are still “in phase” with previous photometric observations: if this is the case, it means that in the “spot” hypothesis, these (superficial?) features would remain in the same position on the photosphere, changing only in surface area and/or brightness with the star's activity.
The nonlinear dynamics of energetic-particle (EP) driven geodesic acoustic modes (EGAM) is investigated here. A numerical analysis with the global gyrokinetic particle-in-cell code ORB5 is performed, and the results are interpreted with the analytical theory, in close comparison with the theory of the beam-plasma instability. Only axisymmetric modes are considered, with a nonlinear dynamics determined by wave–particle interaction. Quadratic scalings of the saturated electric field with respect to the linear growth rate are found for the case of interest. As a main result, the formula for the saturation level is provided. Near the saturation, we observe a transition from adiabatic to non-adiabatic dynamics, i.e. the frequency chirping rate becomes comparable to the resonant EP bounce frequency. The numerical analysis is performed here with electrostatic simulations with circular flux surfaces, and kinetic effects of the electrons are neglected.
Synchrotron-based micro-X-ray fluorescence (μXRF) equipment has been used to analyze impurities in polar ice. A customized sample holder has been developed and the μXRF equipment has been adapted with a thermal control system to keep samples unaltered during analyses. Artificial ice samples prepared from ultra-pure water were analyzed to investigate possible contamination and/or experimental artefacts. Analyses of polar ice from Antarctica (Dome C and Vostok) confirm this μXRF technique is non-destructive and sensitive. Experiments can be reproduced to confirm or refine results by focusing on interesting spots such as crystal grain boundaries or specific inclusions. Integration times and resolution can be adjusted to optimize sensitivity. Investigation of unstable particles is possible due to the short analysis time. In addition to identification of elements in impurities, μXRF is able to determine their speciations. The accuracy and reliability of the results confirm the potential of this technique for research in glaciology.
Inversing the STICS crop model with remote-sensing-derived leaf area index (LAI) and yield data from the previous crop is used to retrieve some soil permanent properties and crop emergence parameters. Spatialized nitrogen (N) fertilization recommendations are provided to farmers, for the second and third N applications, following the screening of eleven N application rates under a range of possible forthcoming climates, with the objective to maximize of the gross margin while respecting some environmental constraints. As a first field validation, we show (1) the improvement brought by the assimilation of LAI and yield into STICS to simulate crop and soil variables and (2) the interest of site specific application to maximize both the gross margin and the agro-environmental criterion.
For 5 out of 28 known rapidly oscillating magnetic chemically peculiar (roAp) stars, the largest observed frequency seems to exceed the theoretical acoustic cutoff frequency, which is determined by the outermost stellar regions. We show that a better modelling of the atmosphere reconciles the theory with the observations for at least the roAp star α Cir.
For stars cooler than 6400°K, the lithium is observed to be depleted with respect to the universal value for Population I stars. The depletion depends on mass and age and occurs, both during the main-sequence (Hyades) and the pre-main-sequence (Pleiades).
Solar models have been computed using the code CESAM constructed at Nice (Morel, 1992), and the new opacities of Livermore for different mixtures. Their global characteristics, predicted capture rates of neutrinos for the chlorine and gallium experiments and their seismological properties are given.
From models of the Sun atmosphere obtained with ATLAS 9 (Kurucz 1992) it appears that the diffusion limit of the transfer equation becomes valid only at depths larger than TR ~ 10. Even with physics as consistent as possible one restores the atmosphere with an accuracy not better than ~ 40%, but with small consequences on solar calibrated models. Despite the eigenmodes have turning points located in the atmosphere, the study of the oscillations reveals differences less than 2μHz when the atmosphere is restored with various assumptions.
CESAM is a consistent set of programs and routines designed for the calculations of stellar evolution. Untill now it allows the computation of the evolution from PMS or ZAMS to helium flash for stellar masses of some solar mass. It is constructed in such a way that all the physics works as external routines. The numerical techniques are based on the B-spline formalism. This formalism used both for the integration of the differential equations and for 1D and 2D interpolation schemes of various tables of physical data.
Penetrative convection is expected below stellar convection sones, where it should achieve a nearly adiabatic stratification. A theoretical prediction of the penetration depth has been recently made by Zahn (1991) which includes an arbitrary parameter ζ depending on the properties of the convective motions. We use the helioseismological constraints to calibrate the value of this parameter.
We have made a clear detection of p-mode oscillations in the G2V star α Cen A with the CORALIE spectrograph. The power spectrum clearly shows several identifiable peaks between 1.8 and 2.9 mHz. A preliminary astrophysical interpretation of these p-modes is presented.
The objective of this study was to assess the effectiveness of a catheter-related bloodstream infection (CR BSI) reduction programme and healthcare workers' compliance with recommendations. A 3-year surveillance programme of CR BSIs in all hospital settings was implemented. As part of the programme, there was a direct observation of insertion and maintenance of central venous catheters (CVCs) to determine performance. A total of 38 education courses were held over the study period and feedback reports with the results of surveillance and recommendations were delivered to healthcare workers every 6 months. A total of 6722 short-term CVCs were inserted in 4982 patients for 58 763 catheter-days. Improvements of compliance with hand hygiene was verified at the insertion (87·1–100%, P < 0·001) and maintenance (51·1–72·1%, P = 0·029) of CVCs; and the use of chlorhexidine for skin disinfection was implemented at insertion (35·7–65·4%, P < 0·001) and maintenance (33·3–45·9%, P < 0·197) of CVCs. There were 266 CR BSI incidents recorded with an annual incidence density of 5·75/1000 catheter-days in the first year, 4·38 in the second year [rate ratio (RR) 0·76, 95% confidence interval (CI) 0·57–1·01] and 3·46 in the third year (RR 0·60, 95% CI 0·44–0·81). The education programme clearly improved compliance with recommendations for CVC handling, and was effective in reducing the burden of CR BSIs.
Studying exoplanets with their parent stars is crucial to understand their population, formation and history. We review some of the key questions regarding their evolution with particular emphasis on giant gaseous exoplanets orbiting close to solar-type stars. For masses above that of Saturn, transiting exoplanets have large radii indicative of the presence of a massive hydrogen-helium envelope. Theoretical models show that this envelope progressively cools and contracts with a rate of energy loss inversely proportional to the planetary age. The combined measurement of planetary mass, radius and a constraint on the (stellar) age enables a global determination of the amount of heavy elements present in the planet interior. The comparison with stellar metallicity shows a correlation between the two, indicating that accretion played a crucial role in the formation of planets. The dynamical evolution of exoplanets also depends on the properties of the central star. We show that the lack of massive giant planets and brown dwarfs in close orbit around G-dwarfs and their presence around F-dwarfs are probably tied to the different properties of dissipation in the stellar interiors. Both the evolution and the composition of stars and planets are intimately linked.
The B fields in OB stars (BOB) survey is an ESO large programme collecting spectropolarimetric observations for a large number of early-type stars in order to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. As of July 2014, a total of 98 objects were observed over 20 nights with FORS2 and HARPSpol. Our preliminary results indicate that the fraction of magnetic OB stars with an organised, detectable field is low. This conclusion, now independently reached by two different surveys, has profound implications for any theoretical model attempting to explain the field formation in these objects. We discuss in this contribution some important issues addressed by our observations (e.g., the lower bound of the field strength) and the discovery of some remarkable objects.
Time-resolved photoluminescence experiments at varying temperature are performed on a series of InxGa1−xN/GaN quantum well and quantum box samples of similar compositions (0.15 < x < 0.20). The results are analyzed by using envelope-function calculations of transition energies and oscillator strengths, accounting for internal electric fields. The respective influences of localization and electric fields on radiative and nonradiative lifetimes and on the Stokes shift are deduced. The results indicate that the spatial extension of localization centers is much smaller than the size of the quantum boxes (∼10 × 3 nm, typically). The room-temperature radiative efficiency of both quantum well and quantum box samples is enhanced by replacing the topmost GaN barrier by an AlGaN one.
Previously, the pressure, temperature and strain rate sensitivities of transformation plasticity have been investigated for monotonic loading of Mg- PSZ. Research in this area has been extended to fully reversed cyclic loading of the type used in plastic strain control fatigue. Cyclic deformation experiments were performed to permit investigation of constitutive behavior under stable deformation conditions at microstrain levels. It was found that cyclic microstrains over a range of temperatures and strain rates were associated with reversible transformation plasticity in the strongly thermally-activated regime. These results are compared to the constitutive relations of transformation plasticity which have been previously developed to explain macrostrain observations.
The constitutive behavior of transformation plasticity in single phase fine grain Ce-TZP and polyphase coarse grain Mg-PSZ was studied. A material independent pressure sensitivity and a microstructure dependent strain rate sensitivity and temperature sensitivity were found to be associated with the transformation yield stress. Autocatalysis of various extent operates in all cases, forming broad macroscopic shear bands in TZP and fine crystallographic slip bands which terminate at grain boundaries in PSZ. Transformation plasticity is apparently athermal near the Mb temperature in TZP, but not in PSZ except in brittle fracture. A strong crystallographic texture of the transformed phase develops during deformation. These results are analyzed in terms of a shear-dilatant yield criterion and a rate equation which account for stress assistance in martensitic transformation. An elastic-plastic fracture mechanical model is developed to estimate both the shear and dilatation contributions to the transformation plastic work in the crack tip plastic zone. On the basis of approximately equal shear and dilatation contributions to transformation plasticity, the model predicts a transformation zone height which is four times that of the previous model, and a toughness increment which is two times that of the previous model. These predictions are found in good agreement with the reported toughness-zone size relationship. The effect of temperature and chemical stability on toughness is also rationalized.
During the five years of the mission, the Gaia spectrograph, the Radial Velocity
Spectrometer (RVS) will repeatedly survey the celestial sphere down to magnitude
V ~ 17–18. This talk presents: (i) the system which is currently developed within
the Gaia Data Processing and Analysis Consortium (DPAC) to reduce and calibrate the
spectra and to derive the radial and rotational velocities, (ii) the RVS expected
performances and (iii) scientific returns.