Weak localization of light in hot atomic vapors

We theoretically explore the possibility to detect weak localization of light in a hot atomic vapor, where one usually expects the fast thermal motion of the atoms to destroy any interference in multiple scattering. To this end, we compute the coherent backscattering peak, assuming high temperature and taking into account the quantum level structure of the atomic scatterers. It is found that the decoherence due to thermal motion can be partially counterbalanced by working at large laser detuning and using small atomic cells with an elongated geometry. Under these conditions, our estimates suggest that weak localization in a hot vapor should be within reach of experimental detection.Comment: 11 pages, 5 figure

Impact d'une intoxication aluminique postnatale précoce sur l'épithélium duodénal de Rat : Etudes en microscopie électronique à transmission et en microanalyse de rayons X

The effects of postnatal aluminium exposure, on microvillus surface area and elements concentration of duodenal enterocytes in rats, were studied by electronic microscopy and X-Ray microanalysis. A significant decrease, of the microvillus wide, was detected by Aluminium chloride (100 mg A l / k g / d a y ) and Aluminium lactate ( 100 and 200 mg Al/kg/day) treatments. A significant variation of K, Ca, S and Fe concentrations was observed by Aluminium chloride (100 mg Al/kg/day) and Aluminium lactate (200 mg AI / kg / day ) intoxication. No effect on elements concentration was detected by Aluminium lactate (100 mg Al/kg/day) intoxicationL'impact de l'aluminium a été étudié sur la morphologie de la surface absorbante ainsi que sur la concentration en éléments des cellules épithéliales duodénales chez le Rat. Une diminution significative du diamètre des microvillosités a été constatée lors d'une intoxication au chlorure d ' aluminium (100 mg Al/kg/j) et au lactate d ' aluminium (100 et 200 mg Al/kg/j). Une variation dans la teneur en K, Ca, S et Fe a été observée lors d'une intoxication au chlorure d'aluminium (100 mg Al/kg/j) et au lactate d'aluminium (200 mg Al/kg/j). Par contre un traitement au lactate d'aluminium (100 mg Al/kg/j) n'a pas d'influence sur la concentration en élément

Effet d'une intoxication aluminique par intubation gastrique chez le Rat adulte : Etude comparative avec le Rat en développement

Adulte male rats were treated by gastric intubation by aluminum chloride (0, 100 mg Al/kg/day) and aluminum lactate (0, 100 and 200 mg Al/kg/day) during 10 days. The results indicated a decreased food consumption, a reduction in body weight, a significant decrease of the plasma concentration of total proteins and a significant increase of the aluminum concentration in hepatic homogenates at 100 mg Al chloride and 200mg Al lactate. On the contrary, the aluminum concentrations in the plasma and cérébral homogenates did not significantly differ between the various groupsL'aluminium administré par intubation gastrique à des rats mâles adultes durant 10 jours entraîne un ralentissement de la prise alimentaire et de la croissance à la dose de 100 mg Al/kg/j (chlorure d'aluminium), et à celle de 200 mg Al/kg/j (lactate d'aluminium). Une chute du taux des protéines plasmatiques totales et une élévation de la concentration en aluminium dans le foie sont également observées. Par contre, les teneurs en aluminium plasmatique et cérébrale ne varient pas. Les effets des intoxications chez les rats adultes sont beaucoup moins importants que ceux constatés chez de jeunes rats intoxiqués dans les mêmes condition

Casimir-Polder force fluctuations as spatial probes of dissipation in metals

We study the spatial fluctuations of the Casimir-Polder force experienced by an atom or a small sphere moved above a metallic plate at fixed separation distance. We demonstrate that unlike the mean force, the magnitude of these fluctuations crucially relies on the relaxation of conduction electron in the metallic bulk, and even achieves values that differ by orders of magnitude depending on the amount of dissipation. We also discover that fluctuations suffer a spectacular decrease at large distances in the case of nonzero temperature.Comment: 6 pages, 5 figure