Transport of indirect excitons in ZnO quantum wells

We report on spatially- and time-resolved emission measurements and observation of transport of indirect excitons in ZnO/MgZnO wide single quantum wells

Demonstrating the decoupling regime of the electron-phonon interaction in a quantum dot using chirped optical excitation

Excitation of a semiconductor quantum dot with a chirped laser pulse allows excitons to be created by rapid adiabatic passage. In quantum dots this process can be greatly hindered by the coupling to phonons. Here we add a high chirp rate to ultra-short laser pulses and use these pulses to excite a single quantum dot. We demonstrate that we enter a regime where the exciton-phonon coupling is effective for small pulse areas, while for higher pulse areas a decoupling of the exciton from the phonons occurs. We thus discover a reappearance of rapid adiabatic passage, in analogy to the predicted reappearance of Rabi rotations at high pulse areas. The measured results are in good agreement with theoretical calculations.Comment: Main manuscript 5 pages and 4 figures, Supplementary Information 5 pages and 3 figures, submitted to PR

Intersubband plasmons induced negative refraction at mid-IR frequency in heterostructured semiconductor metamaterials

We theoretically and experimentally demonstrate negative refraction in a semiconductor system operating at mid-infrared wavelengths. Such effect is generic and realized by electrons quantum confinement in quantum wells, acting as an adjustable resonance

A new syndrome of the Charolais neonatal calf : paralysis in gastroenteritis. Il. Virulence markers CS31A and col V in Escherichia coli isolated from feces

Un syndrome diarrhéique associé à des troubles nerveux (gastro-entérites paralysantes = GEP) a été décrit antérieurement chez des veaux Charoláis d’environ 10 jours. L’étude comparative des colibacilles de la flore fécale de 15 veaux malades et de 9 veaux témoins en bonne santé, a montré que le syndrome GEP est significativement associé à la présence d’une flore fécale colibacillaire où dominent des E. coli pouvant coloniser fortement l’intestin (plasmides p CS31 A, p col V, p K99). Une hypothèse étiopathogé- nique est proposée selon laquelle une bactériémie colibacillaire d’origine digestive avec endotoxémie pourrait expliquer certaines manifestations clini ques des GEP.A diarrheic syndrome associated with nervous troubles (paralysing gastroenteritis) was previously described in 10 days old Charolais calves. Comparative studies of E. coli from fecal flora of 15 ill calves and 9 control healthy calves indicated that PGE was significantly associated with a dominating E. coli fecal flora able to highly colonize the gut (p CS31A, p col V or p K99 plasmids). An etiopathogenic hypothesis is proposed. E. coli bacteriemia with a digestive origin associated with endotoxemia could explain a part of clinical signs in PGE

Cleaved-facet violet laser diodes with lattice-matched Al0.82In0.18N/GaN multilayers as n-cladding

Electrically injected, edge-emitting cleaved-facet violet laser diodes were realized using a 480 nm thick lattice matched Si doped Al0.82In0.18N/GaN multilayer as the cladding on the n-side of the waveguide. Far-field measurements verify strong mode confinement to the waveguide. An extra voltage is measured and investigated using separate mesa structures with a single AlInN insertion. This showed that the electron current has a small thermally activated shunt resistance with a barrier of 0.135 eV and a current which scales according to V-n, where n similar to 3 at current densities appropriate to laser operation. (C) 2011 American Institute of Physics. (doi:10.1063/1.3589974

Discovery and mapping of a new expressed sequence tag-single nucleotide polymorphism and simple sequence repeat panel for large-scale genetic studies and breeding of Theobroma cacao L.

Theobroma cacao is an economically important tree of several tropical countries. Its genetic improvement is essential to provide protection against major diseases and improve chocolate quality. We discovered and mapped new expressed sequence tag-single nucleotide polymorphism (EST-SNP) and simple sequence repeat (SSR) markers and constructed a high-density genetic map. By screening 149 650 ESTs, 5246 SNPs were detected in silico, of which 1536 corresponded to genes with a putative function, while 851 had a clear polymorphic pattern across a collection of genetic resources. In addition, 409 new SSR markers were detected on the Criollo genome. Lastly, 681 new EST-SNPs and 163 new SSRs were added to the pre-existing 418 co-dominant markers to construct a large consensus genetic map. This high-density map and the set of new genetic markers identified in this study are a milestone in cocoa genomics and for marker-assisted breeding. The data are available at http://tropgenedb.cirad.fr

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