In situ detection of gliosis and apoptosis in the brains of young rats exposed in utero to a Wi-Fi signal

International audiencePregnant rats were daily whole-body exposed or sham-exposed to a Wi-Fi signal in a free-running reverberation chamber at 0, 0.08, 0.4, and 4 W/kg for 2 h during the last 2 weeks of gestation (5 days/week). Following this in utero exposure, the pups were divided into two groups and 1 group continued exposure for 5 weeks after birth. Several brain areas were examined for gliosis and apoptotic cells. Comparison among sham and exposed groups revealed no significant differences, suggesting that in utero and post-natal exposure to Wi-Fi did not damage the brains of the young rats

Contribution a l'etude de radiometres millimetriques pour application meteorologique

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Etude sociologique des pratiques corporelles chez les Tamouls de nationalité française de Pondichéry (Sud de l'Inde) (la complémentarité négociée des rôles sexués comme mode d'acculturation spécifique)

MONTPELLIER-BU Médecine UPM (341722108) / SudocMONTPELLIER-BU STAPS (341722109) / SudocPARIS-BIUP (751062107) / SudocMONTPELLIER-BU Médecine (341722104) / SudocSudocFranceF

Système actif hyper-fréquences porté par drone

Dans le cadre d’activités cal-val pour des missions d’observation de la Terre et pour l’étude des zones désertiques (paléo-hydrologie), nous développons un système actif hyper-fréquences en bandes C (5-6 GHz) et P(1-2 GHz) porté par drone. L’objectif est de pouvoir acquérir rapidement des profils de rétrodiffusion, type géoradar mais calibrés en amplitude, pour caractériser la réponse hyper-fréquences de surfaces naturelles. Deux prototypes ont été développés, basés sur un VNA commercial compact et des antennes cornet, et embarqués sur des porteurs DJI (M200 pour la bande C et M600 pour la bande L). Nous présenterons les premiers résultats obtenus sur des sites naturels en Aquitaine, ainsi qu’une comparaison avec des données géo-radar

A phase signature for detecting wet subsurface structures using polarimetric L-band SAR

International audienceIn this paper, we investigate the ability of L-band synthetic aperture radar (SAR) systems to penetrate soils to retrieve information about subsurface wet structures. Our experiment site, the Pyla dune, is a bare sandy area allowing high radar penetration and known to have large wet subsurface structures (paleosoils) at varying depths. Buried paleosoils, which act as moisture tanks, are detectable with radar, since they present a high permittivity due to their water content. By analyzing airborne polarimetric SAR data, we established that a phase signature is correlated to the buried wet palesoils: a phase difference of 23/spl deg/ between the horizontal (HH) and vertical (VV) channels was clearly observed. It allows detection of the paleosoil down to a larger depth (5.2 m) than when only considering HH and HV amplitude signals (3.5 m). In order to confirm this result, field measurements were performed that led to the same observed phase difference. We could fit our observations to the semiempirical model proposed by Oh and Sarabandi, and we reproduced the observed phenomenon using a two-layer integral equation method (IEM) model of the Pyla dune, which was completed by finite-difference time-domain (FDTD) numerical simulations. We show that the soil moisture significantly influences the radar response in terms of phase difference between the copolarized modes. Our study also shows that the single-scattering IEM model reproduces the observed phase difference fairly well for a natural outdoor site when combined to FDTD simulation results. This phase signature could be used as a new tool to map subsurface moisture in arid regions

Effect of head-only exposure to GSM-900 MHz on BBB permeability and neuronal degeneration

International audienc

In-situ multifrequency dielectric measurements to improve soil permittivity models for radiometric observations of soil in the high latitudes

International audienceIn the context of soil monitoring from microwave radiometric observations, the knowledge of the soil permittivity is an important factor in order to guarantee the accuracy of models inversions. Previous studies have showed the impact of temperature and moisture gradients in the top soil layer on remote sensing monitoring of soil. So, we aim here to investigate a way to increase our knowledge of the permittivity profile of the top soil layer, in particular at the P and L band. The solution we selected is based on a new equipment for continuous in-situ measurements of dielectric soil profiles. First measurement results over a sandy soil after rainfall are presented