pinecone/core-2020-05-10-deduplication huggingface dataset:
HESS-II reconstruction strategy and performance in the low-energy (20-150 GeV) domain

International audienceIn mid-2009 a notable upgrade of the H.E.S.S. telescope system will take place: a new telescope with a 600 m2 mirror area and very-high-resolution camera (0.07°) will be positioned at the centre of the present configuration, with the aim of lowering the threshold and enhance its sensitivity in the 100 GeV to several TeV energy range. HESS-II will permit the investigation of the lower energy gamma-ray spectra in various cosmic accelerators, giving information on the origin of the gamma-rays observed, and will detect AGNs with a redshift greater than 0.2 (being less affected by absorption by Extragalactic Background Light-EBL-in this energy range) and will search for new classes of very high energy gamma-ray emitters (pulsars, microquasars, GRB, and dark matter candidates)
Results from observations of AGNs with the H.E.S.S. telescope system and Future plans

Springer-Verlag series "ESO Astrophysics Symposia"International audienceThe H.E.S.S. (High Energy Stereoscopic System) phase I is comprised of four Imaging Atmospheric Cherenkov telescopes, for observation of galactic and cosmic sources of very high energy gamma rays. Its installation in the Khomas highlands, Namibia has been completed in December, 2003. The first of these telescopes was installed in June 2003, and data-taking has proceeded since that time. The HESS telescope system provides a significant improvement in sensitivity and a threshold for detection below that of previous Imaging Atmospheric Cherenkov Telescopes. The characteristics for the phase-I will be presented, together with plans for phase-II of the experiment, comprised of a large telescope in the centre of the current phase-I providing a lowered threshold and increased sensitivity. We can observe AGNs up to redshift 0.5 with HESS and 2-3 with HESS Phase-2, which provides a unique capability for study of spectral and temporal characteristics on timescales of several hours or even less than 1 h (depending on the strength of flares). We will present the first results from a number of southern AGN observed during the installation of the phase-I, in particular concerning the detection and spectral properties of the AGN PKS2155$-$305
Estimation of losses in a 300 m filter cavity and quantum noise reduction in the KAGRA gravitational-wave detector

International audienceThe sensitivity of the gravitational-wave detector KAGRA, presently under construction, will be limited by quantum noise in a large fraction of its spectrum. The most promising technique to increase the detector sensitivity is the injection of squeezed states of light, where the squeezing angle is dynamically rotated by a Fabry-Pérot filter cavity. One of the main issues in the filter cavity design and realization is the optical losses due to the mirror surface imperfections. In this work we present a study of the specifications for the mirrors to be used in a 300 m filter cavity for the KAGRA detector. A prototype of the cavity will be constructed at the National Astronomical Observatory of Japan, inside the infrastructure of the former TAMA interferometer. We also discuss the potential improvement of the KAGRA sensitivity, based on a model of various realistic sources of losses and their influence on the squeezing amplitude
Crystallization of Ge2Sb2Te5 nanometric phase change material clusters made by gas-phase condensation

International audienceThe crystallization behavior of Ge2Sb2Te5 nanometric clusters was studied using X-ray diffraction with in situannealing. Clusters were made using a sputtering gas-phase condensation source, which allowed for the growth of well-defined, contaminant-free, and isolated clusters. The average size for the clusters is 5.7 ± 1 nm. As-deposited amorphous clusters crystallize in the fcc cubic phase at 180 °C, while for thin films, the phase change temperature is 155 °C. This observation illustrates the scalability of the Ge2Sb2Te5phase change from the amorphous to the cubic state in three-dimensionally confined systems in this size range
Spatial particle correlations in light nuclei. I Two-particle systems

Expressions for spatial two-particle correlations in an LS-coupled basis of the harmonic oscillator are used to display the probability distribution of two identical nucleons as a function of their relative distance and their distance from the center of the nucleus. It is shown that a two-nucleon state in the p shell with total orbital angular momentum L = 0 and total spin S = 0 contains a di-neutron and a cigarlike component with equal probability. This result can also be proven analytically with the use of angular correlation functions. Scattering of the nucleons from the p shell to other shells leads to the enhancement of the di-neutron con guration. A semi-quantitative application to 6He is presented which shows that the probability of the di-neutron con guration in the ground state is of the order of 60%. The longterm goal of this work is to obtain a geometric insight into the properties of nuclei with several nucleons in a valence shell
Penalization modeling of a limiter in the Tokamak edge plasma

International audienceAn original penalization method is applied to model the interaction of magnetically confined plasma with limiter in the frame of minimal transport model for ionic density and parallel momentum. The limiter is considered as a pure particle sink for the plasma and consequently the density and the momentum are enforced to be zero inside. Comparisons of the numerical results with one dimensional analytical solutions show a very good agreement. In particular, presented method provides a plasma velocity which is almost sonic at the boundaries obstacles as expected from the sheath conditions through the Bohm criterion. The new system being solved in an obstacle free domain, an efficient pseudo-spectral algorithm based on a Fast Fourier transform is also proposed, and associated with an exponential filtering of the unphysical oscillations due to Gibbs phenomenon. Finally, the efficiency of the method is illustrated by investigating the flow spreading from the plasma core to the Scrape Off Layer at the wall in a two-dimensional system with one then two limiters neighboring
Structure-function strategies to improve the pharmacological value of animal toxins.

ISBN : 978-0-12-369442-3Animal venoms are rich sources of bioactive compounds that possess obvious pharmacological, therapeutic and/or biotechnological values. A majority of these compounds are peptides that mainly target enzymes, membrane receptors or ion channels. These peptides are most often in a size range that allows their production in vitro by chemical synthesis or genetic engineering. Unfortunately, they rarely display the required characteristics in terms of selectivity, affinity, stability and targeting with regard to the desired application. In recent years, a number of structural approaches or strategies have been developed to improve the intrinsic potential of venom peptides. They are reviewed herein for their effectiveness
Past environment and climate changes at the last Interglacial/Glacial transition (Les Échets, France) inferred from subfossil chironomids (Insecta)

International audienceSubfossil chironomid assemblages spanning the last Interglacial/Glacial transition at Les Échets (France) highlight the environmental and climatic changes that took place at this crucial period. The Early Eemian warming is marked by increased percentages of warmwater taxa and decreased percentages of coldwater taxa. In the Middle Eemian, a lowering in water level is indicated by a rise of littoral taxa. In the Late Eemian, chironomids indicate anoxic deep waters and rise of water level, probably induced by increased rainfall. Mélisey I and II and the beginning of the glacial period are marked by the reappearance of coldwater taxa, lower percentages of warmwater taxa, and dominance of littoral taxa, probably correlated with lower water level and climate aridity. St Germain I and II are marked by higher percentages of warmwater taxa, lower percentages, or absence of both coldwater and littoral taxa
Gravimetric evidences of active faults and underground structure of the Cheliff seismogenic basin (Algeria)

International audienceThe Cheliff basin (ex El Asnam) is known as one of the most seismic active zone in Algeria and the West Mediterranean region. We can cite the El Asnam earthquake which occurred in 10.10.01980 with magnitude of 7.3. It was generated by a thrust fault with NE–SW sinistral component. Until now, there is a little information about existence of deep active faults, which generate this strong activity. The gravity field is an important resource of information on crustal structure. The aim of this work is giving a reliable geometry of the major faults relative to the kinematics of this region.The results obtained from various filtered maps (derivatives, upward continuation) of the gravity data, were used to generate a structural map of the studied area. Whilst the continuous wavelet transform method can help in automatic detection of elongated structures in 3-D, to estimate their strike direction, shape and depth. It gives a 3-D image or a model of the region and confirms the existence of several faults, localized or inferred, from former geological studies
Analytical estimates of electron quasi-linear diffusion by fast magnetosonic waves

International audience[1] Quantifying the loss of relativistic electrons from the Earth's radiation belts requires to estimate the effects of many kinds of observed waves, ranging from ULF to VLF. Analytical estimates of electron quasi-linear diffusion coefficients for whistler-mode chorus and hiss waves of arbitrary obliquity have been recently derived, allowing useful analytical approximations for lifetimes. We examine here the influence of much lower frequency and highly oblique, fast magnetosonic waves (also called ELF equatorial noise) by means of both approximate analytical formulations of the corresponding diffusion coefficients and full numerical simulations. Further analytical developments allow us to identify the most critical wave and plasma parameters necessary for a strong impact of fast magnetosonic waves on electron lifetimes and acceleration in the simultaneous presence of chorus, hiss, or lightning-generated waves, both inside and outside the plasmasphere. In this respect, a relatively small frequency over ion gyrofrequency ratio appears more favorable, and other propitious circumstances are characterized. This study should be useful for a comprehensive appraisal of the potential effect of fast magnetosonic waves throughout the magnetosphere. Citation: Mourenas, D., A. V. Artemyev, O. V. Agapitov, and V. Krasnoselskikh (2013), Analytical estimates of electron quasi-linear diffusion by fast magnetosonic waves
Analysis of a periodic optimal control problem connected to microalgae anaerobic digestion

International audienceIn this work, we study the coupling of a culture of microalgae limited by light and an anaerobic digester in a two-tank bioreactor. The model for the reactor combines a periodic day-night light for the culture of microalgae and a classical chemostat model for the digester. We first prove the existence and attraction of periodic solutions of this problem for a 1 day period. Then, we study the optimal control problem of optimizing the production of methane in the digester during a certain timeframe, the control on the system being the dilution rate (the input flow of microalgae in the digester). We apply Pontryagin's Maximum Principle in order to characterize optimal controls, including the computation of singular controls. We present numerical simulations by direct and indirect methods for different light models and compare the optimal 1-day periodic solution to the optimal strategy over larger timeframes. Finally, we also investigate the dependence of the optimal cost with respect to the volume ratio of the two tanks
Texturing in the Earth's inner core due to preferential growth in its equatorial belt

soumis à PEPIInternational audienceWe propose an extension of the model by Yoshida et al. (1996), where deformation in the inner core is forced by preferential growth in the equatorial belt, by taking into account the presence of a stable compositional stratification. Stratification inhibits vertical motion, imposes a flow parallel to isodensity surfaces, and concentrates most deformation in a shallow shear layer of thickness $\sim B^{-1/5}$, where $B$ is the dimensionless buoyancy number. The localization of the flow results in large strain rates and enables the development of a strong alignment of iron crystals in the upper inner core. We couple our dynamical model with a numerical model of texture development and compute the time evolution of the lattice preferred orientation of different samples in the inner core. With sufficient stratification, texturing is significant in the uppermost inner core. In contrast, the deeper inner core is unaffected by any flow and may preserve a fossil texture. We investigate the effect of an initial texture resulting from solidification texturing at the ICB. In the present inner core, the deformation rate in the shallow shear layer is large and can significantly alter the solidification texturing, but the solidification texture acquired early in the inner core history can be preserved in the deeper part. Using elastic constants from \textit{ab initio} calculations, we predict different maps of anisotropy in the modern inner core. A model with both solidification texturing and subsequent deformation in a stratified inner core produces a global anisotropy in reasonable agreement with seismological observations
Estimation of local extreme suspended sediment concentrations in California Rivers

International audienceThe total amount of suspended sediment load carried by a stream during a year is usually transported during one or several extreme events related to high river flow and intense rainfall, leading to very high suspended sediment concentrations (SSCs). In this study quantiles of SSC derived from annual maximums and the 99th percentile of SSC series are considered to be estimated locally in a site-specific approach using regional information. Analyses of relationships between physiographic characteristics and the selected indicators were undertaken using the localities of 5-km radius draining of each sampling site. Multiple regression models were built to test the regional estimation for these indicators of suspended sediment transport. To assess the accuracy of the estimates, a Jack-Knife re-sampling procedure was used to compute the relative bias and root mean square error of the models. Results show that for the 19 stations considered in California, the extreme SSCs can be estimated with 40–60% uncertainty, depending on the presence of flow regulation in the basin. This modelling approach is likely to prove functional in other Mediterranean climate watersheds since they appear useful in California, where geologic, climatic, physiographic, and land-use conditions are highly variable
North western Alps Holocene paleohydrology recorded by flooding activity in Lake Le Bourget, France and possible relations with Mont-Blanc glaciers fluctuations

International audienceA 14-m long piston core was retrieved from Lake Le Bourget, NWAlps (France), in order to provide a continuous record of flooding events of the Rhone River during the Holocene. The selection of the coring site was based on high resolution seismic profiling, in an area with limited mass wasting deposits and accumulated proximal Rhone River inter-and underflow deposits. The age-depth model of this core is based on (i) 14 AMS radiocarbon dates, (ii)radionuclide dating(137Cs) and (iii) the identification of historical data (flood events, eutrophication of the lake).The sedimentary record dates back to 9400 cal BP, and includes a thin mass wasting event deposited around 4500 cal BP. A multi-proxy approach was used to track the evolution and origin of clastic sedimentation during the Holocene, in order to identify periods of higher hydrologic al activity in the catchment area. Spectrophotometry was used to detect fluctuations in clastic supply and the study of clay minerals (especially the Illite crystallinity index) allowed locating the main source area of fine grained clastic particles settling at the lake after flood events. This dataset highlights up to 12 periods of more intense flooding events over the last 9400 years in Lake Le Bourget and shows that the main source area of clastic particles during this period is the upper part of the Arve River drainage basin. This part of the catchment area drains several large glaciers from the Mont-Blanc Massif, and fluctuations in Rhone River flood supply in Lake Le Bourget is interpreted as resulting essentially from Mont-Blanc Glacier activity during the Holocene.The comparison of clastic sedimentationin Lake Le Bourget with periods of increasing land use and periods of Alpine glacier and mid-European lake level fluctuations, suggest that the core LDB04 clastic record in Lake Le Bourget is a continuous proxy of the Holocene hydrologic al history of the NW Alps
Landslide susceptibility assessment by bivariate methods at large scales: Application to a complex mountainous environment

International audienceStatistical assessment of landslide susceptibility has become a major topic of research in the last decade. Most progress has been accomplished on producing susceptibility maps at meso-scales (1:50,000–1:25,000). At 1:10,000 scale, which is the scale of production of most regulatory landslide hazard and risk maps in Europe, few tests on the performance of these methods have been performed. This paper presents a procedure to identify the best variables for landslide susceptibility assessment through a bivariate technique (weights of evidence, WOE) and discusses the best way to minimize conditional independence (CI) between the predictive variables. Indeed, violating CI can severely bias the simulated maps by over- or under-estimating landslide probabilities. The proposed strategy includes four steps: (i) identification of the best response variable (RV) to represent landslide events, (ii) identification of the best combination of predictive variables (PVs) and neo-predictive variables (nPVs) to increase the performance of the statistical model, (iii) evaluation of the performance of the simulations by appropriate tests, and (iv) evaluation of the statistical model by expert judgment. The study site is the north-facing hillslope of the Barcelonnette Basin (France), affected by several types of landslides and characterized by a complex morphology. Results indicate that bivariate methods are powerful to assess landslide susceptibility at 1:10,000 scale. However, the method is limited from a geomorphological viewpoint when RVs and PVs are complex or poorly informative. It is demonstrated that expert knowledge has still to be introduced in statistical models to produce reliable landslide susceptibility maps
Paleomagnetic of Upper Jurassic to Lower Cretecous volcanic and sedimentary rocks from the western Tarim abd implications for inclination shallowing and absolute dating of the M0 (ISEA) chron.

International audienceStepwise demagnetization isolates a stable magnetic component in 13 sites of basalt flows and baked sediments dated at 113.3±1.6 Ma from the Tuoyun section, western Xinjiang Province, China. Except for one flow from the base of the 300 m thick section, the rest have exclusively reversed polarity. The sequence correlates with chron M-0 in some geomagnetic polarity time scales, which potentially places the section just before the start of the Cretaceous Long Normal polarity superchron. Five of 11 sites of Early Cretaceous red beds that underlie the basalts possess coherent directions that pass both fold and reversals tests. Six sites of Upper Jurassic red beds have a magnetic component that was likely acquired after folding in the Tertiary. The mean paleolatitude of the Lower Cretaceous red beds is 11° lower than that of the Lower Cretaceous basalts suggesting the red beds underestimate the true field inclination. We further test this result by calculating the paleolatitudes to a common point of the available Early Cretaceous to Present paleomagnetic poles from red beds and volcanic rocks from central Asian localities north of the Tibetan Plateau. We find that paleolatitudes of volcanic rocks roughly equal the paleolatitudes calculated from the reference Eurasian apparent polar wander path (APWP) and that paleolatitudes of red beds are generally 10-20° lower than the paleolatitudes of volcanic rocks and those predicted from the reference curve. Our study suggests that central Asian red beds poorly record the Earth's field inclination, which leads to lower than expected paleolatitudes. Good agreement in paleolatitudes from volcanic rocks and the Eurasian APWP argues against proposed canted and non-dipole field models
Robust PRNG based on homogeneously distributed chaotic dynamics

International audienceThis paper is devoted to the design of new chaotic Pseudo Random Number Generator (CPRNG). Exploring several topologies of network of 1-D coupled chaotic mapping, we focus first on two dimensional networks. Two topologically coupled maps are studied: T T L (RC) non-alternate, and T T L (SC) alternate. The primary idea of the novel maps has been based on an original coupling of the tent and logistic maps to achieve excellent random properties and homogeneous /uniform/ density in the phase plane, thus guaranteeing maximum security when used for chaos base cryptography. In this aim two new nonlinear CPRNG: M T T L (SC 2) and N T T( L2) are proposed. The maps successfully passed numerous statistical, graphical and numerical tests, due to proposed ring coupling and injection mechanisms
First VLTI/MIDI observations of a Be star: Alpha Arae

International audienceWe present the first VLTI/MIDI observations of the Be star alpha Ara (HD 158 427), showing a nearly unresolved circumstellar disk in the N band. The interferometric measurements made use of the UT1 and UT3 telescopes. The projected baselines were 102 and 74 meters with position angles of 7 ° and 55°, respectively. These measurements put an upper limit on the envelope size in the N band under the uniform disk approximation of φmax= 4±1.5 mas, corresponding to 14 R*, assuming R*=4.8 Rȯ and the Hipparcos distance of 74 pc. On the other hand the disk density must be large enough to produce the observed strong Balmer line emission. In order to estimate the possible circumstellar and stellar parameters we have used the SIMECA code developed by Stee et al. (1995, A&A, 300, 219) and Stee & Bittar (2001, A&A, 367, 532). Optical spectra taken with the échelle instrument Heros and the ESO-50 cm telescope, as well as infrared ones from the 1.6m Brazilian telescope were used together with the MIDI spectra and visibilities. These observations place complementary constraints on the density and geometry of the alpha Ara circumstellar disk. We discuss the potential truncation of the disk by a companion and we present spectroscopic indications of a periodic perturbation of some Balmer lines
Externalities, consumption constraints and regular economies

Voir Documents de travail du Centre d'Economie de la Sorbonne 2008.11 : http://halshs.archives-ouvertes.fr/halshs-00257731/fr/International audienceWe consider a general model of pure exchange economies with consumption externalities. Households may have different consumption sets and each consumption set is described by a function called the possibility function. Utility and possibility functions depend on the consumptions of all households. Showing by means of an example that basic assumptions are not enough to guarantee generic regularity, we provide sufficient conditions for generic regularity in the space of endowments and possibility functions