pinecone/core-2020-05-10-deduplication huggingface dataset:
Trends of labile trace metals in tropical urban water under highly contrasted weather conditions

International audienceThe spatio-temporal trend of trace metals (Cd, Co, Cr, Cu, Ni, Pb, and Zn) in a tropical urban estuary under the influence of monsoon was determined using diffusive gradient in thin films (DGT) in situ samplers. Three different climatic periods were observed: period 1, dry with dredging activity; period 2, intermediate meaning from dry to wet event; and period 3, wet having continuous rainfall. Conforming to monsoon regimes, these periods correspond to the following: transition from winter to summer, winter, and summer monsoons, respectively. The distinction of each period is defined by their specific hydrological and physico-chemical conditions. Substantial concentrations of the trace metals were detected. The distribution and trend of the trace metals under the challenge of a tropical climate were able to follow using DGT as a sensitive in situ sampler. In order to identify the differences among periods, statistical analyses were performed. This allowed discriminating period 2 (oxic water) as significantly different compared to other periods. The spatio-temporal analysis was then applied in order to distinguish the trend of the trace metals. Results showed that the trend of trace metals can be described according to their response to (i) seasonal variations (Cd and Cr), (ii) spatio-temporal conditions (Co, Cu, Ni, and Pb), and (iii) neither (i) nor (ii) meaning exhibiting no response or having constant change (Zn). The correlation of the trace metals and the physico-chemical parameters reveals that Cd, Co, Cu, and Cr are proportional to the dissolved oxygen (DO), Cd and Ni are correlated pH, and Zn lightly influenced by salinity
Suzaku X-ray Follow-up Observations of Seven Unassociated Fermi-LAT Gamma-ray Sources at High Galactic Latitudes

International audienceWe report on our second-year campaign of X-ray follow-up observations of unidentified Fermi-LAT \gamma-ray sources at high Galactic latitudes (|b|>10 degree) using the X-ray Imaging Spectrometer onboard the Suzaku X-ray Observatory. In this second year of the project, seven new targets were selected from the First Fermi-LAT Catalog, and studied with 20-40 ks effective Suzaku exposures. We detected an X-ray point source coincident with the position of the recently discovered millisecond pulsar PSR J2302+4442 within the 95% confidence error circle of 1FGL J2302.8+4443. The X-ray spectrum of the detected counterpart was well fit by a blackbody model with temperature of kT ~0.3 keV, consistent with an origin of the observed X-ray photons from the surface of a rotating magnetized neutron star. For four other targets which were also recently identified with a normal pulsar (1FGL J0106.7+4853) and millisecond pulsars (1FGL J1312.6+0048, J1902.0-5110, and J2043.2+1709), only upper limits in the 0.5-10 keV band were obtained at the flux levels of ~10^{-14} erg cm^{-2} s^{-1}. A weak X-ray source was found in the field of 1FGL J1739.4+8717, but its association with the variable \gamma-ray emitter could not be confirmed with the available Suzaku data alone. For the remaining Fermi-LAT object 1FGL J1743.8-7620 no X-ray source was detected within the LAT 95% error ellipse. We briefly discuss the general properties of the observed high Galactic-latitude Fermi-LAT objects by comparing their multiwavelength properties with those of known blazars and millisecond pulsars
Meteor hurricane at Mars on 2014 October 19 from comet C/2013 A1

International audienceComet C/2013 A1 will make a very close approach with the planet Mars on 2014 October 19. For this event, we compute the density of cometary dust particles around the Mars Express spacecraft, in order to assess the real risk for space probes. We also estimate the zenithal hourly rate (ZHR) and discuss observational opportunities for the resulting Martian meteor shower. We find, for a surface of 2.7 m 2 , that the Mars Express spacecraft will experience approximately 10 impacts from particles larger than 100 µm in size. The fluence per square metre is found to be 3.5 during the encounter. The equivalent ZHR is computed to be ZHR 4.75 × 10 9 h −1 , making this event the strongest meteor storm ever predicted. We call this event a 'meteor hurricane', which we define to be a meteor shower with ZHR exceeding 10 6 h −1
VUV photoionization and dissociative photoionization spectroscopy of the interstellar molecule aminoacetonitrile: Theory and experiment

International audienceAminoacetonitrile (AAN) is a key compound in astrochemistry and astrobiology. We present a combined theoretical and experimental investigation concerning the single photoionization of gas-phase AAN and the fragmentation pathways of the resulting cation. At present, we measured photoelectron photoion coincidence (PEPICO) spectra in the 9.8–13.6 eV energy regime using synchrotron radiation as exciting light source. In order to interpret the VUV experimental data obtained, we explored the ground potential energy surface (PES) of AAN and of its cation using standard and explicitly correlated quantum chemical methodologies. This allowed us to deduce accurate thermochemical data for this molecule. We also determined, for the first time, the adiabatic ionization energy of AAN to lie at AIE = (10.085 ± 0.03) eV. The unimolecular decomposition pathways of the resulting AAN+ parent cation are also investigated. The appearance energies of five fragments are determined for the first time, with 30 meV accuracy. Interestingly, our work shows the possibility of the formation of both HCN and HNC isomeric forms. The implications for the evolution of prebiotic molecules under VUV irradiation are briefly discussed
On the  determination and constancy of the solar oblateness

International audienceThe equator-to-pole radius difference (Δr=R eq−R pol) is a fundamental property of our star, and understanding it will enrich future solar and stellar dynamical models. The solar oblateness (Δ⊙) corresponds to the excess ratio of the equatorial solar radius (R eq) to the polar radius (R pol), which is of great interest for those working in relativity and different areas of solar physics. Δr is known to be a rather small quantity, where a positive value of about 8 milli-arcseconds (mas) is suggested by previous measurements and predictions. The Picard space mission aimed to measure Δr with a precision better than 0.5 mas. The Solar Diameter Imager and Surface Mapper (SODISM) onboard Picard was a Ritchey–Chrétien telescope that took images of the Sun at several wavelengths. The SODISM measurements of the solar shape were obtained during special roll maneuvers of the spacecraft by 30° steps. They have produced precise determinations of the solar oblateness at 782.2 nm. After correcting measurements for optical distortion and for instrument temperature trend, we found a solar equator-to-pole radius difference at 782.2 nm of 7.9±0.3 mas (5.7±0.2 km) at one σ. This measurement has been repeated several times during the first year of the space-borne observations, and we have not observed any correlation between oblateness and total solar irradiance variations
C2 interpolation of spatial data subject to arc-length constraints using Pythagorean-hodograph quintic splines

International audienceIn order to reconstruct spatial curves from discrete electronic sensor data, two alternative C2 Pythagorean-hodograph (PH) quintic spline formulations are proposed, interpolating given spatial data subject to prescribed constraints on the arc length of each spline segment. The first approach is concerned with the interpolation of a sequence of points, while the second addresses the interpolation of derivatives only (without spatial localization). The special structure of PH curves allows the arc-length conditions to be expressed as algebraic constraints on the curve coefficients. The C2 PH quintic splines are thus defined through minimization of a quadratic function subject to quadratic constraints, and a close starting approximation to the desired solution is identified in order to facilitate efficient construction by iterative methods. The C2 PH spline constructions are illustrated by several computed examples
Trans-stereospecific polymerization of butadiene and random copolymerization with styrene using borohydrido neodymium/magnesium dialkyl catalysts

11 pagesInternational audienceThe combination of a neodymium borohydride, Nd(BH4)3(THF)3 (1) or Cp*Nd(BH4)2(THF)x (2), with MgnBuEt (BEM), affords an efficient and highly selective (up to 96.7% 1,4-trans) catalyst for butadiene polymerization. In the presence of excesses of Mg co-catalyst, polymer chain transfer takes place between neodymium and magnesium, and significant amounts of 1,2-units are observed. When considered for butadiene-styrene statistical copolymerization, the catalytic system based on 2 showed a good ability to produce poly[(1,4-trans-butadiene)-co-styrene)], with strong impact of the Mg/Nd ratio on the yield and on the copolymer microstructure, including the percentage of inserted styrene (up to 16.9 mol%). Whatever the co-monomers concentration the polybutadiene backbone remained 1,4-trans. The precise microstructure of the polymers and copolymers was thoroughly analyzed by means of high resolution NMR spectroscopy (900 MHz) and MALDI-ToF spectrometry
Electromagnetic study of the quality factor of pillar microcavities in the small diameter limit

International audienceA thorough electromagnetic study of pillar microcavities reveals a surprising behavior for their Q factors in the strong confinement limit. Q displays a fast oscillatory variation as a function of the pillar diameter, and reaches values well in excess of the quality factor of the reference planar cavity. This behavior is explained by the hybrid character of the cavity mode in the small diameter limit, which results mainly from the electromagnetic coupling of the HE11 (i.e., fundamental) and EH11 guided modes of the cavity spacer through the associated Bloch modes in the Bragg mirrors
A second order anti-diffusive Lagrange-remap scheme for two-component flows

CEMRACS'10 research achievements: numerical modeling of fusion. Papers from the 15th Annual Summer Research Session (Centre d'étude Mathématique de Recherche Avancée en Calcul Scientifique) held in Marseille, July 19-August 27, 2010International audienceWe build a non-dissipative second order algorithm for the approximate resolution of the one-dimensional Euler system of compressible gas dynamics with two components. The considered model was proposed in Allaire, Clerc and Kokh (2002). The algorithm is based on Kokh and Lagoutière (2010) which deals with a non-dissipative first order resolution in Lagrange-remap formalism. In the present paper we describe, in the same framework, an algorithm that is second order accurate in time and space, and that preserves sharp interfaces. Numerical results reported at the end of the paper are very encouraging, showing the interest of the second order accuracy for genuinely non-linear waves
(A)geostrophic adjustment of dipolar perturbations, formation of coherent structures and their properties, as follows from high-resolution numerical simulations with rotating shallow water model

International audienceIn the general context of the geostrophic adjustment, we study the formation of coherent structures in a rotating shallow water model on the f-plane starting from localized dipolar configurations We perform direct numerical simulations with such initial conditions with the help of a well-balanced high-resolution finite-volume numerical scheme Initializations with geostrophically balanced quasigeostrophic modons with high enough Rossby numbers lead to adjustment toward quasistationary coherent ageostrophic dipoles Like in laboratory experiments, cyclonic potential vorticity is being detrained from the dipoles and their trajectories bend Comparisons with recently found exact steady-moving localized dipolar solutions show similarities and differences at the same time Initializations with unbalanced dipolar initial conditions lead to similar quasistationary configurations at high enough effective Rossby numbers At low Rossby numbers the classical geostrophic adjustment is observed Ageostrophic quasistationary dipoles emerging from the simulations are surprisingly robust They undergo frontal collisions with an exchange of cyclonic partners, which are essentially elastic and do not change their structure They also keep coherence when encountering a steep topography and ballistically transport passive tracers (C) 2010 American Institute of Physics [doi 10 1063/1 3514200
Impact of synkinematic sedimentation on the geometry and dynamics of compressive growth structures: Insights from analogue modelling

International audienceAnalogue sandbox models have been set up to study the impact of synkinematic deposits on the geometry and evolution of single thrusts and folds according to different sedimentation modes (a slow or rapid sedimentation rate that is constant or changing in space and time) and rheological profiles (thin or thick sedimentary series, with or without a basal décollement level). A first series of experiments documents the influence of synkinematic deposits according to their sedimentation rate and the rheology of the prekinematic materials. A second series investigates the influence of changes in the sedimentation rate through time. A third one considers the influence of changes in the sedimentation rate in space. All these experiments suggest that the geometry and evolution of single compressive growth structures vary according to the sedimentation rate. The number and dip of their frontal thrust segments change with the ratio R between the sedimentation rate at the footwall of the faults and the uplift rate of their hanging wall. The latter is then more or less uplifted depending on the dip of the thrusts. As a result, the overall structure has either a fault-bend fold or a fault-propagation fold geometry. These rules are verified when the ratio R changes in space or through time. In addition, the rheological profile of the models also affects the geometry and evolution of compressive growth structures. Their structural style, as well as the synsedimentary splitting and steepening of the associated thrusts, varies according to the occurrence and strength of the brittle and ductile layers. According to this modelling study, the ratio R and its changes in space and time, along with the rheology of the deformed materials, are key parameters to better understand the geometrical and kinematical complexities of natural growth thrusts and folds and to improve their interpretation
Application of geophysical measurements for assessing the role of fissures in water infiltration within a clay landslide (Trièves area, French Alps)

Soumis à Hydrological Processes, accepté définitivement ; en attente de publication.International audienceRainfall and its consequences are usually considered as the major factor trig- gering slope instabilities within clay deposits. The link between rainfall, water inltration and landslide activity may be complex and comprehensive sets of data are still necessary to understand how water inltrates in cohesive material. On unstable slopes made of ne-grained sediments, gravitational deformation generates supercial shear ruptures and tension ssures whose continuous opening could be amplied by shrinkage during dry periods. This ssure network at the surface can be very dense and strongly controls the water inltration process. However, it re- mains dicult to assess the ssure evolution at depth and its eventual relationship with shallow slip surfaces. This work presents the results of a geophysical study which aimed to characterize the ssures that are observed along the unstable clay slopes of the Trieves area (French Alps). The site was rst investigated combining geomorphological analysis, drilling, borehole logging, geotechnical tests and geo- physical experiments. This investigation evidenced the presence of at least three rupture surfaces (at 5m, 10 to 15m and 42m) with a water ow at the second one. In a second step, permanent instruments were installed (piezometers and soil water content (SWC) probes). Results indicate high water inltration velocities, down to the water table located at 2.5m depth, that are likely to be linked with sub-vertical preferential paths, such as ssures. Geophysical parameters (electrical resistivity, S-wave velocities, Rayleigh waves attenuation) were monitored. Geophysical results suggest that ssures are permanently open, that they serve as preferential inltra- tion paths, and that they can reach, at least, a depth of 2m. The methods employed in this research put forward that the system of imbricated ssures drains water from the surface down to the shallow slip surfaces at 5m and 10-5m. This work highlights the role of ssures network in water inltration in the numerous clay landslides of the Trieves area
The core-collapse rate from the Supernova Legacy Survey

We use three years of data from the Supernova Legacy Survey (SNLS) to study the general properties of core-collapse and type Ia supernovae. This is the first such study using the "rolling search" technique which guarantees well-sampled SNLS light curves and good efficiency for supernovae brighter than i'~24. Using host photometric redshifts, we measure the supernova absolute magnitude distribution down to luminosities 4.5 mag fainter than normal SNIa. Using spectroscopy and light-curve fitting to discriminate against SNIa, we find a sample of 117 core-collapse supernova candidates with redshifts z < 0.4 (median redshift of 0.29) and measure their rate to be larger than the type Ia supernova rate by a factor 4.5±0.8(stat.)±0.6 (sys.). This corresponds to a core-collapse rate at z = 0.3 of [ 1.42±0.3(stat.)±0.3(sys.)] ×10-4 yr-1(h_70-1 Mpc)-3
U–Pb zircon dating of post-obduction volcanic-arc granitoids and a granulite-facies xenolith from New Caledonia. Inference on Southwest Pacific geodynamic models.

International audienceIn New Caledonia, the occurrence of one of the World's largest and best-exposed subduction/ obduction complex is a key point for the understanding of the geodynamic evolution of the whole Southwest Pacific region. Within the ophiolite, pre-and postobduction granitoids intrude the ultramafic allochthon and provide new time constraints for the understanding of obduction processes. At 27.4 Ma, a new East-dipping subduction generated the active margin magmatism along the western coast of the island (Saint-Louis massif). At 24.3 Ma, the eastward shift of the magma activity and slightly different geochemical features (Koum-Borindi massif) was either related to the older slab break-off; or alternatively, due to the eastward migration of the mantle wedge following the collision of the eastern margin of the Low Howe rise. Finally, the occurrence of a granulite-facies xenolith in the Koum-Borindi massif with comparable 24.5 Ma U–Pb zircon age and isotopic features (initial eNd = 5.1) suggests that these evolved magmas were generated within the lithospheric mantle beneath a continental crust of normal thickness. Geochronological evidence for continuous convergence during the Oligocene infers an East-dipping Eocene-Oligocene subduction/obduction system to have existed in the Southwest Pacific from the d'Entrecasteaux zone to the North Island of New Zealand
Interpreting microarray experiments via co-expressed gene groups analysis

International audienceMicroarray technology produces vast amounts of data by measuring simultaneously the expression levels of thousands of genes under hundreds of biological conditions. Nowadays, one of the principal challenges in bioinformatics is the interpretation of huge data using different sources of information. We propose a novel data analysis method named CGGA (Co-expressed Gene Groups Analysis) that automatically finds groups of genes that are functionally enriched, i.e. have the same functional annotations, and are co- expressed. CGGA automatically integrates the information of microarrays, i.e. gene expression profiles, with the functional annotations of the genes obtained by the genome-wide information sources such as Gene Ontology (GO)1. By applying CGGA to well-known microarray experiments, we have identified the principal functionally enriched and co-expressed gene groups, and we have shown that this approach enhances and accelerates the interpretation of DNA microarray experiments
The Back and Forth Nudging algorithm for data assimilation problems: theoretical results on transport equations

International audienceIn this paper, we consider the back and forth nudging algorithm that has been introduced for data assimilation purposes. It consists of iteratively and alternately solving forward and backward in time the model equation, with a feedback term to the observations. We consider the case of 1-dimensional transport equations, either viscous or inviscid, linear or not (Bürgers' equation). Our aim is to prove some theoretical results on the convergence, and convergence properties, of this algorithm. We show that for non viscous equations (both linear transport and Burgers), the convergence of the algorithm holds under observability conditions. Convergence can also be proven for viscous linear transport equations under some strong hypothesis, but not for viscous Burgers' equation. Moreover, the convergence rate is always exponential in time. We also notice that the forward and backward system of equations is well posed when no nudging term is considered
Modelling the effect of in-stream and overland dispersal on gene flow in river networks

International audienceModelling gene flow across natural landscapes is a current challenge of population genetics. Models are essential to make clear predictions about conditions that cause genetic differentiation or maintain connectivity between populations. River networks are a special case of landscape matrix. They represent stretches of habitat connected according to a branching pattern where dispersal is usually limited to upstream or downstream movements. Because of their peculiar topology, and the increasing concern about conservation issues in hydrosystems, there has been a recent revival of interest in modelling dispersal in river networks. Network complexity has been shown to influence global population differentiation. However, geometric characteristics are likely to interact with the way individuals move across space. Studies have focused on in-stream movements. None of the work published so far took into consideration the ability of many species to disperse overland between branches of the same network though. We predicted that the relative contribution of these two dispersal modalities (in-stream and overland) would affect the overall genetic structure. We simulated dispersal in synthetic river networks using an individual-based model.We tested the effect of dispersal modalities, i.e. the ratio of overland/in-stream dispersal, and two geometric parameters, bifurcation angle between branches and network complexity. Data revealed that if geometrical parameters affected population differentiation, dispersal parameters had the strongest effect. Interestingly, we observed a quadratic relationship between p the proportion of overland dispersers and population differentiation. We interpret this U-shape pattern as a balance between isolation by distance caused by in-stream movements at low values of p and intense migrant exchanges within the same branching unit at high values of p. Our study is the first attempt to model out-of-networkmovements. It clearly shows that both geometric and dispersal parameters interact. Both should be taken into consideration in order to refine predictions about dispersal and gene flow in river network