pinecone/core-2020-05-10-deduplication huggingface dataset:
The EROS2 search for microlensing events towards the spiral arms: the complete seven season results

19 pages, submitted to Astronomy and Astrophysicsthe EROS-2 project has been designed to search for microlensing events towards any dense stellar field. The densest parts of the Galactic spiral arms have been monitored to maximize the microlensing signal expected from the stars of the Galactic disk and bulge. 12.9 million stars have been monitored during 7 seasons towards 4 directions in the Galactic plane, away from the Galactic center. A total of 27 microlensing event candidates have been found. Estimates of the optical depths from the 22 best events are provided. A first order interpretation shows that simple Galactic models with a standard disk and an elongated bulge without a thick disk or a spiral structure are in agreement with our observations. We find that the average microlensing optical depth towards the complete EROS-cataloged stars of the spiral arms is $\bar{\tau} =0.51\pm .13\times 10^{-6}$, a number that is stable when the selection criteria are moderately varied. As the EROS catalog is almost complete up to $I_C=18.5$, the optical depth estimated for the sub-sample of bright target stars with $I_C<18.5$ ($\bar{\tau}=0.39\pm .11\times 10^{-6}$) is easier to interpret. The set of microlensing events that we have observed is consistent with a simple Galactic model. A more precise interpretation would require either a better knowledge of the distance distribution of the target stars, or a simulation based on a Galactic model. For this purpose, we define and discuss the concept of optical depth for a given catalog or for a limiting magnitude
An operational calculus for the Mould operad

Art. ID rnn018 16 pages, one reference added and minor changes in v2International audienceThe operad of moulds is realized in terms of an operational calculus of formal integrals (continuous formal power series). This leads to many simplifications and to the discovery of various suboperads. In particular, we prove a conjecture of the first author about the inverse image of non-crossing trees in the dendriform operad. Finally, we explain a connection with the formalism of noncommutative symmetric functions
Symmetric microwave potentials for interferometry with thermal atoms on a chip

International audienceA trapped atom interferometer involving state-selective adiabatic potentials with two microwave frequencies on a chip is proposed. We show that this configuration provides a way to achieve a high degree of symmetry between the two arms of the interferometer, which is necessary for coherent splitting and recombination of thermal (i.e., noncondensed) atoms. The resulting interferometer holds promise to achieve high contrast and long coherence time, while avoiding the mean-field interaction issues of interferometers based on trapped Bose-Einstein condensates
Herschel/HIFI observations of ionised carbon          in the β          Pictoris debris disk

International audienceContext. The dusty debris disk around the ~20 Myr old main-sequence A-star            β Pictoris          is known to contain gas. Evidence points towards a secondary origin of the gas as opposed          to being a direct remnant from the initial protoplanetary disk, although the dominant gas          production mechanism is so far not identified. The origin of the observed overabundance of          C and O compared with solar abundances of metallic elements such as Na and Fe is also          unclear.Aims. Our goal is to constrain the spatial distribution of C in the          disk, and thereby the gas origin and its abundance pattern.Methods. We used the HIFI instrument on board the Herschel          Space Observatory to observe and spectrally resolve C ii emission at 158            μm from the            β Pic          debris disk. Assuming a disk in Keplerian rotation and a model for the line emission from          the disk, we used the spectrally resolved line profile to constrain the spatial          distribution of the gas.Results. We detect the C ii 158 μm emission. Modelling the          shape of the emission line shows that most of the gas is located at about ~100 AU or beyond. We estimate a total C gas          mass of  1.3-0.5+1.3 × 10-2 M⊕  (central 90%          confidence interval). The data suggest that more gas is located on the south-west side of          the disk than on the north-east side. The shape of the emission line is consistent with          the hypothesis of a well mixed gas (constant C/Fe ratio throughout the disk). Assuming          instead a spatial profile expected from a simplified accretion disk model, we found it to          give a significantly poorer fit to the observations.Conclusions. Since the bulk of the gas is found outside 30 AU, we argue          that the cometary objects known as “falling evaporating bodies” are probably not the          dominant source of gas; production from grain-grain collisions or photodesorption seems          more likely. The incompatibility of the observations with a simplified accretion disk          model might favour a preferential depletion explanation for the overabundance of C and O,          although it is unclear how much this conclusion is affected by the simplifications made.          More stringent constraints on the spatial distribution will be available from ALMA          observations of C i emission at 609 μm
A method of characteristics for solving population balance equations (PBE) describing the adsorption of impurities during crystallization processes

International audiencePossible hindering effects of impurities on the crystal growth were shown to take place because of the adsorption of impurity species on the crystal surface. Transient features of this adsorption were observed, such that the growth of a given crystal does not depend on supersaturation only, but also on the time a given particle spent in contact with impurities present in the mother liquor. Meanwhile, few kinetic models describe the effect of impurities on the growth of crystals in solution, and published models are usually derived from data obtained, thanks to specific experiments based on the evaluation of the growth rate of single crystals. Such models are obviously questionable because, in the industrial practice, distributed properties of crystals are actually involved. Considering the “time of contamination” of particles as a new internal variable is thus made necessary. This is the reason why a specific PBE resolution algorithm is presented in this paper. The numerical scheme for the resolution of PBEs is based on the method of characteristics and shown to allow fast and accurate simulation of transient features of the crystal size distribution in the particular case when the growth or nucleation rates are assumed to exhibit unsteady-state dynamics. The algorithm is finally used to simulate the isothermal desupersaturation crystallization of citric acid in water
Super-resolution method using sparse regularization for point-spread function recovery

International audienceIn large-scale spatial surveys, such as the forthcoming ESA Euclid mission, images may be undersampled due to the optical sensors sizes. Therefore, one may consider using a super-resolution (SR) method to recover aliased frequencies, prior to further analysis. This is particularly relevant for point-source images, which provide direct measurements of the instrument point-spread function (PSF). We introduce SParse Recovery of InsTrumental rEsponse (SPRITE), which is an SR algorithm using a sparse analysis prior. We show that such a prior provides significant improvements over existing methods, especially on low signal-to-noise ratio PSFs
Longitudinal differentiation among pelagic populations in a planktic foraminifer.

Evolutionary processes in marine plankton have been assumed to be dependent on the oceanic circulation system, which transports plankton between populations in marine surface waters. Gene flow facilitated by oceanic currents along longitudinal gradients may efficiently impede genetic differentiation of pelagic populations in the absence of confounding marine environmental effects. However, how responsible oceanic currents are for the geographic distribution and dispersal of plankton is poorly understood. We examined the phylogeography of the planktic foraminifer Pulleniatina obliquiloculata in the Indo-Pacific Warm Pool (IPWP) by using partial small subunit ribosomal DNA (SSU rDNA) sequences. We found longitudinal clines in the frequencies of three distinct genetic types in the IPWP area. These frequencies were correlated with environmental factors that are characteristic of three water masses in the IPWP. Noteworthy, populations inhabiting longitudinally distant water masses at the Pacific and Indian sides of the IPWP were genetically different, despite transportation of individuals via oceanic currents. These results demonstrate that populations of pelagic plankton have diverged genetically among different water masses within a single climate zone. Changes of the oceanic circulation system could have impacted the geographic patterns of dispersal and divergence of pelagic plankton
An intercomparison of measured pressure-broadening, pressure shifting parameters of carbon dioxide and their temperature dependence

International audienceAn intercomparison of measured pressure-broadening and pressure-shifting coefficients for carbon dioxide absorption lines was done. The work focuses on collision systems where a significant number of data can be found (CO2-N2, CO2-O2, CO2-air, and CO2-CO2) and yield information important to applications related to Earth's atmosphere. The literature was searched for measured line shape parameter data for the collision systems mentioned above. Databases were created for each perturbing gas with the ro-vibrational transition as the key. Using these databases intercomparisons of the measurements of half-widths, their temperature dependence, and line shifts were made. The data allow the investigations of trends in the data with respect to the vibrational and the rotational quantum numbers, various line shape models, and isotopologue effects
Timing, cause and impact of the late Eocene stepwise sea retreat from the Tarim Basin (west China)

International audienceA vast shallow epicontinental sea extended across Eurasia and was well-connected to the Western Tethys before it retreated westward and became isolated as the Paratethys Sea. However, the palaeogeography and the timing of this westward retreat are too poorly constrained to determine potential wider environmental impacts, let alone understanding underlying mechanisms of the retreat such as global eustasy and tectonism associated with the Indo-Asia collision. Here, an improved chronostratigraphic and palaeogeographic framework is provided for the onset of the proto-Paratethys Sea retreat at its easternmost extent in the Tarim Basin in western China is provided. Five different third-order sea-level cycles can be recognised from the Cretaceous-Palaeogene sedimentary record in the Tarim Basin, of which the last two stepped successively westwards as the sea retreated after the maximum third incursion. New biostratigraphic data from the fourth and fifth incursions at the westernmost margin of the Tarim Basin are compared to our recent integrated bio-magneto-stratigraphic results on the fourth incursion near the palaeodepocentre in the south-western part of the basin. While the fourth incursion extended throughout the basin and retreated at ~ 41 Ma (base C18r), the last and fifth incursion is restricted to the westernmost margin and its marine deposits are assigned a latest Bartonian-early Priabonian age from ~ 38.0 to ~ 36.7 Ma (near top C17n.2n to base C16n.2n). Similar to the fourth, the fossil assemblages of the fifth incursion are indicative of shallow marine, near-shore conditions and their widespread distribution across Eurasia suggests that the marine connection to the Western Tethys was maintained. The lack of diachronicity of the fourth incursion between the studied sections across the southwest Tarim Basin suggests that the sea entered and withdrew relatively rapidly, as can be expected in the case of eustatic control on a shallow epicontinental basin. However, the westward palaeogeographic step between the fourth and fifth incursions separated by several millions of years rather suggests the combined long-term effect of tectonism, possibly associated with early uplift of the Pamir-Kunlun Shan thrust belt. The fourth and fifth regressions are time-equivalent with significant aridification steps recorded in the Asian interior, thus supporting climate modelling results showing that the stepwise sea retreat from Central Asia amplified the aridification of the Asian interior
Modelling of stylolite geometries and stress scaling

International audienceIn this contribution we present numerical simulations of stylolite growth to decipher the effects of initial rock heterogeneity and stress on their morphology. We show that stylolite growth in a rock with a uniform grain size produces different patterns than stylolite growth in a rock with a bimodal grain size distribution. Strong pinning of large heterogeneities produce stylolite structures that are dominated by pronounced teeth, whereas a uniform grain size leads to spikes and a roughness that shows variable wavelengths. We compare the simulated stylolites with natural examples and show that the model can reproduce the real structures. In addition we show that strong pinning in the bimodal case can lead to a linear stylolite roughness growth in contrast to the non-linear growth of stylolites that develop from a uniform noise. In a set of 24 simulations we vary the main principle stress on the stylolite in order to test if our model can reproduce the analytically derived stress-scaling proposed by Schmittbuhl et al. (2004). We compare the calculated stresses with the applied stresses and show that the numerical model and the analytical solution are in good agreement. Our results strengthen the hypothesis that stylolites can be used as strain and stress gauges to estimate not only the orientation of paleo-stresses, but also their absolute values of formation stresses and amounts of compaction
Apparent close approaches between near-Earth asteroids and quasars. Precise astrometry and frame linking

Reproduced with permission. Copyright ESO. Article published by EDP Sciences and available at www.aanda.org.International audienceAims. We investigate the link between the International Celestial Reference Frame (ICRF) and the dynamical reference frame realized by the ephemerides of the Solar System bodies. Methods. We propose a procedure that implies a selection of events for asteroids with accurately determined orbits crossing the CCD field containing selected quasars. Using a Bulirsch-Stoer numerical integrator, we constructed 8-years (2010-2018) ephemerides for a set of 836 numbered near-Earth asteroids (NEAs). We searched for close encounters (within a typical field of view of groundbased telescopes) between our selected set of asteroids and quasars with high-accuracy astrometric positions extracted from the Large Quasars Astrometric Catalog (LQAC). Results. In the designated period (2010-2018), we found a number of 2924, 14 257, and 6972 close approaches (within 10') between asteroids with a minimum solar elongation value of 60◦and quasars from the ICRF-Ext2, the Very Large Baseline Array Calibrator Survey (VLBA-CS), and the Very Large Array (VLA), respectively. This large number of close encounters provides the observational basis needed to investigate the link between the dynamical reference frame and the ICRF
Causes and impacts of changes in the Arctic freshwater budget during the 20th and 21st centuries in an AOGCM

International audienceThe fourth version of the atmosphere-ocean general circulation (AOGCM) model developed at the Institut Pierre-Simon Laplace (IPSL-CM4) is used to investigate the mechanisms influencing the Arctic freshwater balance in response to anthropogenic greenhouse gas forcing. The freshwater influence on the interannual variability of deep winter oceanic convection in the Nordic Seas is also studied on the basis of correlation and regression analyses of detrended variables. The model shows that the Fram Strait outflow, which is an important source of freshwater for the northern North Atlantic, experiences a rapid and strong transition from a weak state toward a relatively strong state during 1990\u20132010. The authors propose that this climate shift is triggered by the retreat of sea ice in the Barents Sea during the late twentieth century. This sea ice reduction initiates a positive feedback in the atmosphere-sea ice-ocean system that alters both the atmospheric and oceanic circulations in the Greenland-Iceland-Norwegian (GIN)-Barents Seas sector. Around year 2080, the model predicts a second transition threshold beyond which the Fram Strait outflow is restored toward its original weak value. The long-term freshening of the GIN Seas is invoked to explain this rapid transition. It is further found that the mechanism of interannual changes in deep mixing differ fundamentally between the twentieth and twenty-first centuries. This difference is caused by the dominant influence of freshwater over the twenty-first century. In the GIN Seas, the interannual changes in the liquid freshwater export out of the Arctic Ocean through Fram Strait combined with the interannual changes in the liquid freshwater import from the North Atlantic are shown to have a major influence in driving the interannual variability of the deep convection during the twenty-first century. South of Iceland, the other region of deep water renewal in the model, changes in freshwater import from the North Atlantic constitute the dominant forcing of deep convection on interannual time scales over the twenty-first century
Elimination of systematic errors in two-mode laser telemetry

4p.International audienceWe present a simple two-mode telemetry procedure which eliminates cyclic errors, to allow accurate absolute distance measurements. We show that phase drifts and cyclic errors are suppressed using a fast polarization switch that exchanges the roles of the reference and measurement paths. Preliminary measurements obtained using this novel design show a measurement stability better than 1 micron. Sources of residual noise and systematic errors are identified, and we expect that an improved but still simple version of the apparatus will allow accuracies in the nanometre range for absolute measurements of kilometre-scale distances
Are beliefs a matter of taste? A case for Objective Imprecise Information

International audienceWe argue, in the spirit of some of Jean-Yves Jaffray's work, that explicitly incorporating the information, however imprecise, available to the decision maker is relevant, feasible, and fruitful. In particular, we show that it can lead us to know whether the decision maker has wrong beliefs and whether it matters or not, that it makes it possible to better model and analyze how the decision maker takes into account new information, even when this information is not an event and finally that it is crucial when attempting to identify and measure the decision maker's attitude toward imprecise information
Efficient laser-overdense plasma coupling via surface plasma waves and steady magnetic field generation

International audienceThe efficiency of laser overdense plasma coupling via surface plasma wave excitation is investigated. Two-dimensional particle-in-cell simulations are performed over a wide range of laser pulse intensity from 10 15 to 10 20 W cm À2 lm 2 with electron density ranging from 25 to 100n c to describe the laser interaction with a grating target where a surface plasma wave excitation condition is fulfilled. The numerical studies confirm an efficient coupling with an enhancement of the laser absorption up to 75%. The simulations also show the presence of a localized, quasi-static magnetic field at the plasma surface. Two interaction regimes are identified for low (Ik 2 < 10 17 W cm À2 lm 2) and high (Ik 2 > 10 17 W cm À2 lm 2) laser pulse intensities. At " relativistic " laser intensity, steady magnetic fields as high as $580 MG lm/k 0 at 7 Â 10 19 W cm À2 lm 2 are obtained in the simulations
Analysis of limited-diffractive and limited-dispersive X-waves generated by finite radial waveguides

International audienceIn this work, we analyze the spatial and temporal features of electromagnetic X-waves propagating in free space and generated by planar radiating apertures. The performance of ideal X-waves is discussed and compared to practical cases where the important effects related to the finiteness of the radiating aperture and the wavenumber dispersion are taken into account. In particular, a practical device consisting of a radial waveguide loaded with radiating slots aligned along a spiral path is considered for the practical case in the millimeter-wave range. A common mathematical framework is defined for a precise comparison of the spatiotemporal properties and focusing capabilities of the generated X-wave. It is clearly shown that the fractional bandwidth of the radiating aperture has a key role in the longitudinal confinement of an X-wave in both ideal and practical cases. In addition, the finiteness of the radiating aperture as well as the wavenumber dispersion clearly affect both the transverse and the longitudinal profiles of the generated radiation as it travels beyond the depth-of-field of the generated X-wave. Nevertheless, the spatiotemporal properties of the X-wave are preserved even in this "dispersive-finite" case within a defined region and duration related to the nondiffractive range and fractional bandwidth of the spectral components of the generated X-wave. The proposed analysis may open new perspectives for the efficient generation of X-waves over finite radiating apertures at millimeter waves where the dispersive behavior of realistic devices is no longer negligible. Published by AIP Publishing
Convergence of real per capita GDP within COMESA countries: A panel unit root evidence

International audienceThis article examines the absolute and conditional convergence of real GDP per capita in the Common Market for Eastern and Southern Africa (COMESA) during the period 1950-2003. Income departures across countries were evaluated from several panel data unit root tests. We find no evidence supporting the existence of convergence process for the income in the COMESA. Nevertheless, applying economic development criterion allows to identity two absolute convergence clubs into the COMESA, one for the most four developed countries (Egypt, Libya, Mauritius, Seychelles), and one other for the fourteen less developed ones. Thus, we show that most economies of COMESA are locked into a sustained poverty trap process
Optical signatures of borico dyes: a TD-DFT analysis

International audienceUsing time-dependent density functional theory, we investigate the excited-state properties of a series of emissive dyes combining the properties of coumarins and fluoroborate compounds. These boron-iminocoumarins (borico) compounds have been synthesized very recently by Frath et al. (Chem Commun 49:4908, 2013) . We determine both their vertical and 0-0 energies, reproduce and analyze their characteristic experimental band shape, investigate the nature of the excited-states in large dyads containing two different fluoroborate complexes and design red-shifted compounds. We also consider an additional panel of fused coumarin-BODIPY emitters