422 research outputs found

    Desert roughness retrieval using CYGNSS GNSS-R data

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    The aim of this paper is to assess the potential use of data recorded by the Global Navigation Satellite System Reflectometry (GNSS-R) Cyclone Global Navigation Satellite System (CYGNSS) constellation to characterize desert surface roughness. The study is applied over the Sahara, the largest non-polar desert in the world. This is based on a spatio-temporal analysis of variations in Cyclone Global Navigation Satellite System (CYGNSS) data, expressed as changes in reflectivity (G). In general, the reflectivity of each type of land surface (reliefs, dunes, etc.) encountered at the studied site is found to have a high temporal stability. A grid of CYGNSS G measurements has been developed, at the relatively fine resolution of 0.03° x 0.03°, and the resulting map of average reflectivity, computed over a 2.5-year period, illustrates the potential of CYGNSS data for the characterization of the main types of desert land surface (dunes, reliefs, etc.). A discussion of the relationship between aerodynamic or geometric roughness and CYGNSS reflectivity is proposed. A high correlation is observed between these roughness parameters and reflectivity. The behaviors of the GNSS-R reflectivity and the Advanced Land Observing Satellite-2 (ALOS-2) Synthetic Aperture Radar (SAR) backscattering coeffcient are compared and found to be strongly correlated. An aerodynamic roughness (Z0) map of the Sahara is proposed, using four distinct classes of terrain roughness

    Invest to Save: Report and Recommendations of the NSF-DELOS Working Group on Digital Archiving and Preservation

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    Digital archiving and preservation are important areas for research and development, but there is no agreed upon set of priorities or coherent plan for research in this area. Research projects in this area tend to be small and driven by particular institutional problems or concerns. As a consequence, proposed solutions from experimental projects and prototypes tend not to scale to millions of digital objects, nor do the results from disparate projects readily build on each other. It is also unclear whether it is worthwhile to seek general solutions or whether different strategies are needed for different types of digital objects and collections. The lack of coordination in both research and development means that there are some areas where researchers are reinventing the wheel while other areas are neglected. Digital archiving and preservation is an area that will benefit from an exercise in analysis, priority setting, and planning for future research. The WG aims to survey current research activities, identify gaps, and develop a white paper proposing future research directions in the area of digital preservation. Some of the potential areas for research include repository architectures and inter-operability among digital archives; automated tools for capture, ingest, and normalization of digital objects; and harmonization of preservation formats and metadata. There can also be opportunities for development of commercial products in the areas of mass storage systems, repositories and repository management systems, and data management software and tools.

    Les compléments neurophysiologiques du diagnostic

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    Neurophysiological complements of autism diagnosis Research presented show relationships between behavioral and cognitive disorders and underlying cerebral functional abnormalities, on the basis of non invasive electrophysiological investigations (electroencephalography, cortical evoked potentials). Three types of disturbances are studied: sleep problems, intolerance to change and atypical visual processing of human faces. The complementarity of clinical and neurophysiological approaches is crucial at the levels of functional diagnosis, therapeutic and educative interventions

    Ribosomal Incorporation of Aromatic Oligoamides as Peptide Sidechain Appendages

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    Derivatives of 4‐aminomethyl‐l ‐phenylalanine with aromatic oligoamide foldamers as sidechain appendages were successfully charged on tRNA by means of flexizymes. Their subsequent incorporation both at the C‐terminus of, and within, peptide sequences by the ribosome, was demonstrated. These results expand the registry of chemical structures tolerated by the ribosome to sidechains significantly larger and more structurally defined than previously demonstrated

    Xq27 FRAXA locus is a strong candidate for dyslexia: evidence from a genome-wide scan in French families.

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    Dyslexia is a frequent neurodevelopmental learning disorder. To date, nine susceptibility loci have been identified, one of them being DYX9, located in Xq27. We performed the first French SNP linkage study followed by candidate gene investigation in dyslexia by studying 12 multiplex families (58 subjects) with at least two children affected, according to categorical restrictive criteria for phenotype definition. Significant results emerged on Xq27.3 within DYX9. The maximum multipoint LOD score reached 3,884 between rs12558359 and rs454992. Within this region, seven candidate genes were investigated for mutations in exonic sequences (CXORF1, CXORF51, SLITRK2, FMR1, FMR2, ASFMR1, FMR1NB), all having a role during brain development. We further looked for 50 UTR trinucleotide repeats in FMR1 and FMR2 genes. No mutation or polymorphism co-segregating with dyslexia was found. This finding in French families with Dyslexia showed significant linkage on Xq27.3 enclosing FRAXA, and consequently confirmed the DYX9 region as a robust susceptibility locus. We reduced the previously described interval from 6.8 (DXS1227–DXS8091) to 4 Mb also disclosing a higher LOD score

    Crystal structure of a complex between β-glucopyranose and a macrocyclic receptor with dendritic multicharged water solubilizing chains

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    International audienceUsing commercial screens for crystallization of biomolecules and taking advantage of the use of racemic crystallography allowed the production of x-ray quality single crystals and the elucidation at 1.08 Å resolution of the solid state structure of a difficult target: the complex between glucopyranose and a water soluble macrocyclic receptor equipped with dendritic multianionic solubilizing chains

    Ethnography and Modern Languages

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    While rarely explicitly recognized in our disciplinary frameworks, the openness and curiosity on which Modern Languages in the UK is founded are, in many ways, ethnographic impulses. Ethnographic theories and practices can be transformative in relation to the undergraduate curriculum, providing an unparalleled model for experiential and holistic approaches to language and cultural learning. As a form of emplaced and embodied knowledge production, ethnography promotes greater reflexivity on our geographical and historical locations as researchers, and on the languages and cultures through which we engage. An ethnographic sensitivity encourages an openness to less hierarchical and hegemonic forms of knowledge, particularly when consciously seeking to invert the traditional colonial ethnographic project and envision instead more participatory and collaborative models of engagement. Modern Languages scholars are at the same time ideally placed to challenge a monolingual mindset and an insensitivity to language-related questions in existing ethnographic research located in cognate disciplines. For Modern Languages to embrace ethnography with credibility, we propose a series of recommendations to mobilize these new research and professional agendas

    Loading linear arrays of Cu(II) inside aromatic amide helices

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    The very stable helices of 8-amino-2-quinolinecar-boxylic acid oligoamides are shown to uptake CuIIions in theircavity through deprotonation of their amide functions with minimal alteration of their shape, unlike most metallo-organicstructures which generally differ from their organic precursors.The outcome is the formation of intramolecular linear arrays of a defined number of CuIIcenters (up to sixteen in this study)at a 3 distance, forming a molecular mimic of a metal wirecompletely surrounded by an organic sheath. The helices packin the solid state so that the arrays of CuIIextend intermolecularly. Conductive-AFM and cyclic voltammetry suggest thatelectrons are transported throughout the metal-loaded helices in contrast with hole transport observed for analogous foldamers devoid of metal ions.Les voies de signalisation du récepteur 5-HT6: de nouvelles cibles pour le traitement de la douleur neuropathique

    <i>Gaia</i> Data Release 1. Summary of the astrometric, photometric, and survey properties

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    Context. At about 1000 days after the launch of Gaia we present the first Gaia data release, Gaia DR1, consisting of astrometry and photometry for over 1 billion sources brighter than magnitude 20.7. Aims. A summary of Gaia DR1 is presented along with illustrations of the scientific quality of the data, followed by a discussion of the limitations due to the preliminary nature of this release. Methods. The raw data collected by Gaia during the first 14 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into an astrometric and photometric catalogue. Results. Gaia DR1 consists of three components: a primary astrometric data set which contains the positions, parallaxes, and mean proper motions for about 2 million of the brightest stars in common with the HIPPARCOS and Tycho-2 catalogues – a realisation of the Tycho-Gaia Astrometric Solution (TGAS) – and a secondary astrometric data set containing the positions for an additional 1.1 billion sources. The second component is the photometric data set, consisting of mean G-band magnitudes for all sources. The G-band light curves and the characteristics of ∼3000 Cepheid and RR-Lyrae stars, observed at high cadence around the south ecliptic pole, form the third component. For the primary astrometric data set the typical uncertainty is about 0.3 mas for the positions and parallaxes, and about 1 mas yr−1 for the proper motions. A systematic component of ∼0.3 mas should be added to the parallax uncertainties. For the subset of ∼94 000 HIPPARCOS stars in the primary data set, the proper motions are much more precise at about 0.06 mas yr−1. For the secondary astrometric data set, the typical uncertainty of the positions is ∼10 mas. The median uncertainties on the mean G-band magnitudes range from the mmag level to ∼0.03 mag over the magnitude range 5 to 20.7. Conclusions. Gaia DR1 is an important milestone ahead of the next Gaia data release, which will feature five-parameter astrometry for all sources. Extensive validation shows that Gaia DR1 represents a major advance in the mapping of the heavens and the availability of basic stellar data that underpin observational astrophysics. Nevertheless, the very preliminary nature of this first Gaia data release does lead to a number of important limitations to the data quality which should be carefully considered before drawing conclusions from the data
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