Finite element modelling of thermo-elasto-plastic water saturated porous materials

in Journal of Theoretical and Applied Mechanics (2008), 38(1-2), 7-34

The purpose of this paper is to present a new nite element formulation for the hydro-thermo-mechanical analysis of elasto-plastic multiphase materials based on Porous Media Mechanics. To this end, the ... [more ▼]

The purpose of this paper is to present a new nite element formulation for the hydro-thermo-mechanical analysis of elasto-plastic multiphase materials based on Porous Media Mechanics. To this end, the ACMEG-T thermo-plastic constitutive model for saturated soils has been implemented in the nite element code COMES-GEO. Validation of the implemented model is made by selected comparison between model simulation and experimental results for di erent combinations of thermo-hydro-mechanical loading paths. A case of non-isothermal elasto-plastic consolidation is also shown. [less ▲]

Isotope Analysis Reveals Foraging Area Dichotomy for Atlantic Leatherback Turtles

in PLoS ONE (2008), 3(3), 1845

Background: The leatherback turtle (Dermochelys coriacea) has undergone a dramatic decline over the last 25 years, and this is believed to be primarily the result of mortality associated with fisheries ... [more ▼]

Background: The leatherback turtle (Dermochelys coriacea) has undergone a dramatic decline over the last 25 years, and this is believed to be primarily the result of mortality associated with fisheries bycatch followed by egg and nesting female harvest. Atlantic leatherback turtles undertake long migrations across ocean basins from subtropical and tropical nesting beaches to productive frontal areas. Migration between two nesting seasons can last 2 or 3 years, a time period termed the remigration interval (RI). Recent satellite transmitter data revealed that Atlantic leatherbacks follow two major dispersion patterns after nesting season, through the North Gulf Stream area or more eastward across the North Equatorial Current. However, information on the whole RI is lacking, precluding the accurate identification of feeding areas where conservation measures may need to be applied. Methodology/Principal Findings: Using stable isotopes as dietary tracers we determined the characteristics of feeding grounds of leatherback females nesting in French Guiana. During migration, 3-year RI females differed from 2-year RI females in their isotope values, implying differences in their choice of feeding habitats (offshore vs. more coastal) and foraging latitude (North Atlantic vs. West African coasts, respectively). Egg-yolk and blood isotope values are correlated in nesting females, indicating that egg analysis is a useful tool for assessing isotope values in these turtles, including adults when not available. Conclusions/Significance: Our results complement previous data on turtle movements during the first year following the nesting season, integrating the diet consumed during the year before nesting. We suggest that the French Guiana leatherback population segregates into two distinct isotopic groupings, and highlight the urgent need to determine the feeding habitats of the turtle in the Atlantic in order to protect this species from incidental take by commercial fisheries. Our results also emphasize the use of eggs, a less-invasive sampling material than blood, to assess isotopic data and feeding habits for adult female leatherbacks. [less ▲]

Prix Nobel de Chimie 2008: Suivre les protéines à la trace grâce à la GFP («Green Fluorescent Protein»)

in Science et Culture (2008), 416

La GFP permet de voir les protéines directement dans les organismes vivants, de les localiser grâce à la fluorescence qu’elle émet. Par manipulation génétique, on peut accrocher la GFP à diverses ... [more ▼]

La GFP permet de voir les protéines directement dans les organismes vivants, de les localiser grâce à la fluorescence qu’elle émet. Par manipulation génétique, on peut accrocher la GFP à diverses protéines que l’on peut ainsi suivre à la trace dans les cellules en fonctionnement. Comme une large variété de mutants de la GFP émettant des fluorescences de couleurs différentes sont disponibles, on peut même localiser plusieurs protéines simultanément. Quel merveilleux outil pour l’imagerie en microscopie optique ! [less ▲]

Neural network involved in self-judgment in young and elderly adults

Master of advanced studies dissertation (2008)

Short communication: correlations of marker-assisted breeding values with progeny-test breeding values for eight hundred ninety-nine French Holstein bulls.

in Journal of Dairy Science (2008), 91(6), 2520-2

French artificial insemination companies have been running a marker-assisted selection program since 2001 to determine which young bulls should be progeny tested. A first batch of 899 Holstein sires ... [more ▼]

French artificial insemination companies have been running a marker-assisted selection program since 2001 to determine which young bulls should be progeny tested. A first batch of 899 Holstein sires receiving their first proofs based on progeny daughters has been studied. Estimated breeding values with or without marker information were computed based on information available in April 2004, and correlated to daughter yield deviations available in 2007 for production traits. Marker-assisted estimated breeding values presented greater correlations with daughter yield deviations than those calculated using only pedigree index. The average improvement in correlation was 0.043 and ranged from +0.001 for protein yield to +0.103 for fat percentage. This gain was based on the initial and suboptimal conditions of the program and is expected to increase in the coming years because of several improvements implemented since the start of the marker-assisted selection program. [less ▲]

Dynamical, dielectric, and elastic properties of GeTe investigated with first-principles density functional theory

in Physical Review b (2008), 78(20),

The dynamical, dielectric, and elastic properties of GeTe, a ferroelectric material in its low-temperature rhombohedral phase, have been investigated using first-principles density functional theory. We ... [more ▼]

The dynamical, dielectric, and elastic properties of GeTe, a ferroelectric material in its low-temperature rhombohedral phase, have been investigated using first-principles density functional theory. We report the electronic energy bands, phonon-dispersion curves, electronic and low-frequency dielectric tensors, infrared reflectivity, Born effective charges, and elastic and piezoelectric tensors and compare them with the existing theoretical and experimental results, as well as with similar quantities available for other ferroelectric materials, when appropriate. [less ▲]

Potato (Solanum Tuberosum L.) Tuber Physiological Age Index Is A Valid Reference Frame In Postharvest Ageing Studies

in Postharvest Biology & Technology (2008), 50(1), 103-106

Essential yield components of potato crops are influenced by the physiological age of the tubers at planting. Previous studies have attempted to develop biophysical, physiological or biochemical markers ... [more ▼]

Essential yield components of potato crops are influenced by the physiological age of the tubers at planting. Previous studies have attempted to develop biophysical, physiological or biochemical markers of potato tuber ageing. This research note focuses on characterising a physiological age index (PAI) based on sprouting parameters and originally developed by Caldiz et al. [Caldiz, D.O., Fernandez, L.V., Struik, P.C., 2001. Physiological age index: a new, simple and reliable index to assess the physiological age of seed potato tubers based on the haulm killing date and length of the incubation period. Field Crop. Res. 69, 69–79]. The PAI progression of two cultivars (‘Bintje’ and ‘Désirée’) was measured and modelled over 2 harvest years. The preliminary results were consistent with other ageing markers such as the incubation period (IP) and desprouting sensitivity. Under our experimental conditions, the PAI allowed us to describe cultivar-specific and harvest year-specific age variations measured from the time the haulm (foliage) was killed and the mother plant's influence on the tubers was no longer present. By contrast, the IP data displayed a higher inherent variability that impaired their discrimination ability. Critical PAI values corresponding to the main postharvest developmental steps (e.g., dormancy, apical dominance, multiple sprouting) were then identified on the basis of emergence pattern data, allowing us to propose this index as a useful reference frame for future ageing studies. [less ▲]

Range-dependence compensation in airborne bistatic STAP radar for partially-calibrated conformal antenna arrays

Conference (2008)

Immune-mediated respiratory and cardiac disease

in Clinical Immunology of the Dog and Cat”, 2d edition (2008)

Preliminary study of aromatase expression and sexual steroids level in different sexual phenotypic/genotypic combination of Nile tilapia, (Oreochromis niloticus)

Poster (2008)