340 research outputs found
Invest to Save: Report and Recommendations of the NSF-DELOS Working Group on Digital Archiving and Preservation
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.
Le site d'Ă©tude Ă long terme de Fontblanche -
Le site expĂ©rimental de Fontblanche est l'un des trois sites d'expĂ©rimentation de la rĂ©gion mĂ©diterranĂ©enne française, avec celui de PuĂ©chabon dans l'HĂ©rault et celui de Haute-Provence. Il suit l'Ă©volution d'une forĂȘt mĂ©langĂ©e Ă pins d'Alep et Ă chĂȘnes verts soumise au changement climatique et complĂšte ainsi les deux autres sites qui Ă©tudient les Ă©cosystĂšmes Ă chĂȘnaie verte (PuĂ©chabon) et Ă chĂȘnaie blanche (O3HP)
Gaia Data Processing Architecture
Gaia is ESA's ambitious space astrometry mission the main objective of which
is to astrometrically and spectro-photometrically map 1000 Million celestial
objects (mostly in our galaxy) with unprecedented accuracy. The announcement of
opportunity for the data processing will be issued by ESA late in 2006. The
Gaia Data Processing and Analysis Consortium (DPAC) has been formed recently
and is preparing an answer. The satellite will downlink close to 100 TB of raw
telemetry data over 5 years. To achieve its required accuracy of a few 10s of
Microarcsecond astrometry, a highly involved processing of this data is
required.
In addition to the main astrometric instrument Gaia will host a Radial
Velocity instrument, two low-resolution dispersers for multi-color photometry
and two Star Mappers. Gaia is a flying Giga Pixel camera. The various
instruments each require relatively complex processing while at the same time
being interdependent. We describe the overall composition of the DPAC and the
envisaged overall architecture of the Gaia data processing system. We shall
delve further into the core processing - one of the nine, so-called,
coordination units comprising the Gaia processing system.Comment: 10 Pages, 2 figures. To appear in ADASS XVI Proceeding
A snow cover climatology for the Pyrenees from MODIS snow products
International audienceThe seasonal snow in the Pyrenees is critical for hydropower production, crop irrigation and tourism in France, Spain and Andorra. Complementary to in situ observations , satellite remote sensing is useful to monitor the effect of climate on the snow dynamics. The MODIS daily snow products (Terra/MOD10A1 and Aqua/MYD10A1) are widely used to generate snow cover climatologies, yet it is preferable to assess their accuracies prior to their use. Here, we use both in situ snow observations and remote sensing data to evaluate the MODIS snow products in the Pyrenees. First, we compare the MODIS products to in situ snow depth (SD) and snow water equivalent (SWE) measurements. We estimate the values of the SWE and SD best detection thresholds to 40 mm water equivalent (w.e.) and 150 mm, respectively , for both MOD10A1 and MYD10A1. Îș coefficients are within 0.74 and 0.92 depending on the product and the variable for these thresholds. However, we also find a seasonal trend in the optimal SWE and SD thresholds, reflecting the hysteresis in the relationship between the depth of the snow-pack (or SWE) and its extent within a MODIS pixel. Then, a set of Landsat images is used to validate MOD10A1 and MYD10A1 for 157 dates between 2002 and 2010. The resulting accuracies are 97 % (Îș = 0.85) for MOD10A1 and 96 % (Îș = 0.81) for MYD10A1, which indicates a good agreement between both data sets. The effect of vegetation on the results is analyzed by filtering the forested areas using a land cover map. As expected, the accuracies decrease over the forests but the agreement remains acceptable (MOD10A1: 96 %, Îș = 0.77; MYD10A1: 95 %, Îș = 0.67). We conclude that MODIS snow products have a sufficient accuracy for hy-droclimate studies at the scale of the Pyrenees range. Using a gap-filling algorithm we generate a consistent snow cover climatology, which allows us to compute the mean monthly snow cover duration per elevation band and aspect classes. There is snow on the ground at least 50 % of the time above 1600 m between December and April. We finally analyze the snow patterns for the atypical winter 2011â2012. Snow cover duration anomalies reveal a deficient snowpack on the Span-ish side of the Pyrenees, which seems to have caused a drop in the national hydropower production
The water relations of two tropical rainforest species (Virola surinamensis and Eperua falcata): Is Virola unusual as previously reported?
HYDROInternational audienceThe objective of this study was to examine the water relations and hydraulic architecture and vulnerability to cavitation in Virola surinamensis and V. michelii and to compare to similar measurements in Eperua falcata. In several previous reports Virola was seen to have a rather narrow range of xylem pressure potentials (Κx) near zero in the course of a wet-season day while having water fluxes quite close to Eperua. We tested the hypothesis that the narrow range of Κx might be consistent with very high hydraulic conductivities of stems, roots and shoots and high vulnerability to cavitation in Virola compared to Eperua. When this hypothesis proved false we concluded that the previous determinations of Κx might be wrong in Virola due to latex. We re-examined the determination of Κx in Virola by the pressure chamber technique and compared results to determination of Κleaf by the thermocouple psychrometer technique and found that the likely range of Κx are more negative than previously reported. Problems concerning the determination of Κx in species with latex are discussed
Organic-rich sediments in ventilated deep-sea environments: Relationship to climate, sea level, and trophic changes
Xq27 FRAXA locus is a strong candidate for dyslexia: evidence from a genome-wide scan in French families.
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 (DXS1227âDXS8091) to 4 Mb
also disclosing a higher LOD score
Tuning bilayer twist using chiral counterions
From seashells to DNA, chirality is expressed at every level of biological structures. In self-assembled structures it may emerge cooperatively from chirality at the molecular scale. Amphiphilic molecules, for example, can form a variety of aggregates and mesophases that express the chirality of their constituent molecules at a supramolecular scale of micrometres (refs 1-3), Quantitative prediction of the large-scale chirality based on that at the molecular scale remains a largely unsolved problem. Furthermore, experimental control over the expression of chirality at the supramolecular level is difficult to achieve(4-7): mixing of different enantiomers usually results in phase separation(18). Here we present an experimental and theoretical description of a system in which chirality can be varied continuously and controllably ('tuned') in micrometre-scale structures. we observe the formation of twisted ribbons consisting of bilayers of gemini surfactants (two surfactant molecules covalently linked at their charged head groups). We find that the degree of twist and the pitch of the ribbons can be tuned by the introduction of opposite-handed chiral counterions in various proportions. This degree of control might be of practical value; for example, in the use of the helical structures as templates for helical crystallization of macromolecules(8,9).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62619/1/399566a0.pd
Functional foldamers that target bacterial membranes: the effect of charge, amphiphilicity and conformation
By varying the molecular charge, shape and amphiphilicity of a series of conformationally distinct diarylureas it is possible to control the levels of phospholipid membrane lysis using membranes composed of bacterial lipid extracts. From the data obtained, it appears as though the lysis activity observed is not due to charge, conformation or amphiphilicity in isolation, but that surface aggregation, H-bonding and other factors may also play a part. The work provides evidence that this class of foldamer possesses potential for optimisation into new antibacterial agents
Use of reconstituted metabolic networks to assist in metabolomic data visualization and mining
Metabolomics experiments seldom achieve their aim of comprehensively covering the entire metabolome. However, important information can be gleaned even from sparse datasets, which can be facilitated by placing the results within the context of known metabolic networks. Here we present a method that allows the automatic assignment of identified metabolites to positions within known metabolic networks, and, furthermore, allows automated extraction of sub-networks of biological significance. This latter feature is possible by use of a gap-filling algorithm. The utility of the algorithm in reconstructing and mining of metabolomics data is shown on two independent datasets generated with LCâMS LTQ-Orbitrap mass spectrometry. Biologically relevant metabolic sub-networks were extracted from both datasets. Moreover, a number of metabolites, whose presence eluded automatic selection within mass spectra, could be identified retrospectively by virtue of their inferred presence through gap filling
- âŠ