Quantum dash based directly modulated lasers for long-reach access networks

International audienceWe demonstrate an innovative 10 Gbps single mode optical transmitter with the capacity of error free transmission in the range of 0 to 100kms with constant biasing conditions using a Quantum Dash Directly Modulated Laser. We use a commercially available etalon filter as passive optical filter to achieve penalty free transmission with a dynamic extinction ratio (DER) > 6dB over a large range of fiber spans

The maize (Zea mays L.) roothairless3 gene encodes a putative GPI-anchored, monocot-specific, COBRA-like protein that significantly affects grain yield

The rth3 (roothairless 3) mutant is specifically affected in root hair elongation. We report here the cloning of the rth3 gene via a PCR-based strategy (amplification of insertion mutagenized sites) and demonstrate that it encodes a COBRA-like protein that displays all the structural features of a glycosylphosphatidylinositol anchor. Genes of the COBRA family are involved in various types of cell expansion and cell wall biosynthesis. The rth3 gene belongs to a monocot-specific clade of the COBRA gene family comprising two maize and two rice genes. While the rice (Oryza sativa) gene OsBC1L1 appears to be orthologous to rth3 based on sequence similarity (86% identity at the protein level) and maize/rice synteny, the maize (Zea mays L.) rth3-like gene does not appear to be a functional homolog of rth3based on their distinct expression profiles. Massively parallel signature sequencing analysis detected rth3 expression in all analyzed tissues, but at relatively low levels, with the most abundant expression in primary roots where the root hair phenotype is manifested.In situ hybridization experiments confine rth3 expression to root hair-forming epidermal cells and lateral root primordia. Remarkably, in replicated field trials involving near-isogenic lines, the rth3 mutant conferred significant losses in grain yield

DFT and k * p modelling of the phase transitions of lead and tin halide perovskites for photovoltaic cells

Published online 30 october 2013. This work was performed using HPC resources from GENCI-CINES/IDRIS grant 2013-c2013096724.International audience3D hybrid organic perovskites, CH3NH3PbX3 (X = halogen), have recently been used to strongly improve the efficiency of dye sensitized solar cells (DSSC) leading to a new class of low-cost mesoscopic solar cells. CsSnI3 perovskite can also be used for hole conduction in DSSC. Density functional theory and GW corrections are used to compare lead and tin hybrid and all-inorganic perovskites. The room temperature optical absorption is associated to electronic transitions between the spin-orbit split-off band in the conduction band and the valence band. Spin-orbit coupling is about three times smaller for tin. Moreover, the effective mass of relevant band edge hole states is small (0.17). The high temperature phase sequence of CsSnI3 leading to the room temperature orthorhombic phase and the recently reported phases of CH3NH3MI3 (where M = Pb, Sn) close to the room temperature, are also studied. Tetragonal distortions from the ideal cubic phase are analysed by a k * p perturbation, including spin-orbit effect. In addition, the non-centrosymmetric phases of CH3NH3MI3 exhibit a splitting of the electronic bands away from the critical point. The present work shows that their physical properties are more similar to conventional semiconductors than to the absorbers used in DSS

Nine-year spatial and temporal evolution of desert dust aerosols over South and East Asia as revealed by CALIOP

We present a 3-D climatology of the desert dust distribution over South and East Asia derived using CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) data. To distinguish desert dust from total aerosol load we apply a methodology developed in the framework of EARLINET (European Aerosol Research Lidar Network). The method involves the use of the particle linear depolarization ratio and updated lidar ratio values suitable for Asian dust, applied to multiyear CALIPSO observations (January 2007-December 2015). The resulting dust product provides information on the horizontal and vertical distribution of dust aerosols over South and East Asia along with the seasonal transition of dust transport pathways. Persistent high D_AOD (dust aerosol optical depth) values at 532 nm, of the order of 0.6, are present over the arid and semi-arid desert regions. Dust aerosol transport (range, height and intensity) is subject to high seasonality, with the highest values observed during spring for northern China (Taklimakan and Gobi deserts) and during summer over the Indian subcontinent (Thar Desert). Additionally, we decompose the CALIPSO AOD (aerosol optical depth) into dust and non-dust aerosol components to reveal the non-dust AOD over the highly industrialized and densely populated regions of South and East Asia, where the non-dust aerosols yield AOD values of the order of 0.5. Furthermore, the CALIPSO-based short-term AOD and D_AOD time series and trends between January 2007 and December 2015 are calculated over South and East Asia and over selected subregions. Positive trends are observed over northwest and east China and the Indian subcontinent, whereas over southeast China trends are mostly negative. The calculated AOD trends agree well with the trends derived from Aqua MODIS (Moderate Resolution Imaging Spectroradiometer), although significant differences are observed over specific regions.Peer reviewe

Voyage en Orient, textes de S. Aubenas, J. Lacarrière, Paris, Bibliothèque nationale de France/Hazan, 1999, 212 p., 201 ill., bibl., 320 F.

Les institutions publiques n'ont pas toujours peur du nouveau. Le département des Estampes et de la Photographie de la Bibliothèque nationale de France a acquis dès leur parution les premiers albums des pionniers de la photographie, trésor constamment accru de legs et dons d'amateurs. Conservateur à ce département, Sylvie Aubenas nous présente une sélection des premières photos réalisées entre 1850 et 1880 dans l'arc oriental de la Méditerranée: Égypte, Palestine, Syrie et Liban, Turqu..

Vision machine

C’est un des indices de la modernité que l’art, l’approche esthétique, n’aient pas, plus, de place assignée dans la société contemporaine. Nantes, ville de Jules Verne, consacre une exposition aux transformations de la vision telles que diverses conduites artistiques les ont perçues, interprétées et prises en charge depuis une centaine d’années. L’exposition et le livre qui l’explicite ont pour épicentre l’œuvre du viennois américain Frederick Kieslu, actif entre 1920 et 1960. Accueilli à la ..

Voyage en Orient, textes de S. Aubenas, J. Lacarrière, Paris, Bibliothèque nationale de France/Hazan, 1999, 212 p., 201 ill., bibl., 320 F.

Les institutions publiques n'ont pas toujours peur du nouveau. Le département des Estampes et de la Photographie de la Bibliothèque nationale de France a acquis dès leur parution les premiers albums des pionniers de la photographie, trésor constamment accru de legs et dons d'amateurs. Conservateur à ce département, Sylvie Aubenas nous présente une sélection des premières photos réalisées entre 1850 et 1880 dans l'arc oriental de la Méditerranée: Égypte, Palestine, Syrie et Liban, Turqu..