Alexandrite laser source for atmospheric lidar measurements

During the past years, there has been a marked increase in interest in the applications of vibronic solid state lasers to meteorology and atmospheric physics. Two airborne lidar programs are now under development in France. The differential absorption lidar (DIAL) method with vibronic solid state lasers is very attractive for water vapor, temperature and pressure measurements. Alexandrite laser and titanium-sapphire are both suitable for these applications. However, only alexandrite rods are commercially available. The requirements on the laser source for airborne dial applications are two fold: (1) a restriction on laser linewidth and a requirement on stability and tunability with a good spectral purity; and (2) a requirement on the time separation between the two pulses. These constraints are summarized

Assessment of the single-mixture gas assumption for the correlated K-distribution fictitious gas method in H2O-CO2-CO mixture at high temperature

International audienceThis paper deals with the comparison of spectral narrow band models based on the correlated-K (CK) approach in the specific area of remote sensing of plume signatures. The CK models chosen may or may not include the fictitious gas (FG) idea and the single-mixture-gas assumption (SMG). The accuracy of the CK and the CK-SMG as well as the CKFG and CKFG-SMG models are compared, and the influence of the SMG assumption is inferred. The errors induced by each model are compared in a sensitivity study involving the plume thickness and the atmospheric path length as parameters. This study is conducted in two remote-sensing situations with different absolute pressures at sea level (10(5) Pa) and at high altitude (16.6 km, 10(4) Pa). The comparisons are done on the basis of the error obtained for the integrated intensity while leaving a line of sight that is computed in three common spectral bands: 2000-2500 cm(-1), 3450-3850 cm(-1) and 3850-4150 cm(-1). In most situations, the SMG assumption induces negligible differences. Furthermore, compared to the CKFG model, the CKFG-SMG model results In a reduction of the computational time by a factor of 2

Crossbreeding the Sardinian and East Friesian breeds in Sardinia

International audienc

Performances de reproduction et d'élevage des brebis romanov finnoises et croisées: premier bilan des résultats obtenus en france dans les troupeaux expérimentaux de l'INRA et dans quelques troupeaux d'étude

International audienc

HEAVY METAL VAPORIZATION IN FLUIDIZED BED COMBUSTION OF SOLID WASTE AND COAL

Solid samples, either of realistic waste model or coal, and spiked with Cd, Pb or Zn, were burned in an electrically-heated fluid bed reactor coupled to a customized ICP spectrometer, for on-line analysis of vaporized metals. For waste samples, a single kinetic law (whatever the metal), predicting the vaporization characteristic time and the time course of the metal concentration in the solid, was obtained. Tests with burning coal samples, spiked with Cd (at 820°C) and Zn (temperature range 680°C to 820°C), proved that this law is still valid, with a slight tendency to underestimation for both Cd and Zn vaporization rates. The transient metal concentration in burning coal was also very well predicted

Links between topography, wind, deflation, lakes and dust: The case of the Bodélé Depression, Chad

The Bodélé Depression, Chad is the planet's largest single source of dust. Deflation from the Bodélé could be seen as a simple coincidence of two key prerequisites: strong surface winds and a large source of suitable sediment. But here we hypothesise that long term links between topography, winds, deflation and dust ensure the maintenance of the dust source such that these two apparently coincidental key ingredients are connected by land-atmosphere processes with topography acting as the overall controlling agent. We use a variety of observational and numerical techniques, including a regional climate model, to show that: 1) contemporary deflation from the Bodélé is delineated by topography and a surface wind stress maximum; 2) the Tibesti and Ennedi mountains play a key role in the generation of the erosive winds in the form of the Bodélé Low Level Jet (LLJ); 3) enhanced deflation from a stronger Bodélé LLJ during drier phases, for example, the Last Glacial Maximum, was probably sufficient to create the shallow lake in which diatoms lived during wetter phases, such as the Holocene pluvial. Winds may therefore have helped to create the depression in which erodible diatom material accumulated. Instead of a simple coincidence of nature, dust from the world's largest source may result from the operation of long term processes on paleo timescales which have led to ideal conditions for dust generation in the world's largest dust source. Similar processes plausibly operate in other dust hotspots in topographic depressions

Simplification de l'échantillonnage en vue du contrôle laitier qualitatif des brebis et des chèvres

International audienc

Efficacy of Antenatal Corticosteroid Treatment on Neurodevelopmental Outcome according to Head Circumference at Birth

BACKGROUND: There are concerns about the efficacy of antenatal corticosteroid treatment (ACT) in the growth-restricted fetus. OBJECTIVE: To evaluate the effect of ACT on neurodevelopmental outcome at 2 years of corrected age according to the z score of birth head circumference (ZS HC) in a large prospective cohort of preterm infants. METHODS: This study was conducted as a population-based, prospective, multicenter study, including 4,965 infants born between 24 and 33 weeks\u27 gestation and whose status regarding ACT and the measurement of head circumference at birth were available. They were evaluated at 2 years of corrected age to assess neurological outcome. Three approaches were considered to estimate the effect of ACT on neurodevelopment: (i) logistic regression with adjustment on propensity score, (ii) weighted logistic regression using the inverse probability of treatment weighting method, and (iii) 1:1 matching of gestational age, ZS HC, and propensity score between treated and nontreated infants. RESULTS: ACT was documented in 60% of infants. Three groups of infants were considered according to their ZS HC: between -3 and -1 standard deviation (SD), -1 and +1 SD, and +1 and +3 SD, respectively. ACT was associated with a significant improvement of neurodevelopmental outcome only for infants with an ZS HC of between +1 and +3 SD (adjusted OR 1.72; 95% CI 1.06-2.79). Moreover, ORs estimated in the -3 to -1 and +1 to +3 categories were significantly different. CONCLUSION: We found beneficial effects of ACT on neurodevelopmental outcomes at 2 years of corrected age only in preterm infants with a ZS HC >1 SD