pinecone/core-2020-05-10-deduplication huggingface dataset:
Seasonal movements and dispersal patterns: Implications for recruitment and management of willow ptarmigan (Lagopus lagopus)

We investigated the general patterns of movements in willow ptarmigan (Lagopus lagopus) populations. We analyzed data from 300 radiocollared willow ptarmigan from 3 study areas in the Swedish mountain range, and from 2 previous studies of recoveries of wing-tagged chicks from 3 areas in southern Norway. We found that 80% of juvenile females dispersed more than 5 km from their natal area, whereas only 25% of juvenile males established a summer range more than 5 km from the area where they were caught as chicks. Mean dispersal distances of juvenile females were 3 times longer (10.4 km) than those of juvenile males (2.4 km). Movement differences within sexes were not associated with apparent female breeding success or ptarmigan density in the natal area, and adult females migrated between wintering areas used as juveniles and their first breeding site. We found no differences in dispersal distances between the Norwegian and Swedish populations. Movements of adult and juvenile females during spring were similar in all respects. At scales of more than 5 km, the movements of juveniles and adult females play a role in redistributing birds within landscape units, and represent important inter-population movements. The results of this study explain the apparent contradiction between non-compensatory mortality based on data from radio-marked ptarmigan, and the almost complete compensation based on annual counts. Estimating the extent of immigration into areas with high local mortality is difficult because of predation or harvest under conditions of high, fixed emigration and immigration dependent on local conditions. This represents a problem if dispersal distances include areas that are considerably larger than the size of the study are
Abstract Acceleration in Linear Relation Analysis

Author version : http://hal.inria.fr/hal-00787212/enInternational audienceAbstract acceleration is a method that computes the precise abstract effect of loops wherever possible and uses widening in the general case. Thus, it improves both the precision and the efficiency of the analysis. % This article gives a comprehensive tutorial on abstract acceleration: its origins in Presburger-based acceleration including new insights w.r.t. the linear accelerability of linear transformations, methods for simple and nested loops, recent extensions, tools and applications, and a detailed discussion of related methods and future perspectives
Investigation of the mobile granular layer in bedload transport by laminar shearing flows

International audienceThe mobile layer of a granular bed composed of spherical particles is experimentally investigated in a laminar rectangular channel flow. Both particle and fluid velocity profiles are obtained using particle image velocimetry for different index-matched combinations of particles and fluid and for a wide range of fluid flow rates above incipient motion. A full three-dimensional investigation of the flow field inside the mobile layer is also provided. These experimental observations are compared to the predictions of a two-phase continuum model having a frictional rheology to describe particle-particle interactions. Different rheological constitutive laws having increasing degrees of sophistication are tested and discussed
Topological graph polynomials and quantum field theory, Part II: Mehler kernel theories

International audienceWe define a new topological polynomial extending the Bollobas-Riordan one, which obeys a four-term reduction relation of the deletion/contraction type and has a natural behavior under partial duality. This allows to write down a completely explicit combinatorial evaluation of the polynomials, occurring in the parametric representation of the non-commutative Grosse-Wulkenhaar quantum field theory. An explicit solution of the parametric representation for commutative field theories based on the Mehler kernel is also provided
Bayesian Joint Detection-Estimation of cerebral vasoreactivity from ASL fMRI data

International audienceAlthough the study of cerebral vasoreactivity using fMRI is mainly conducted through the BOLD fMRI modality, owing to its relatively high signal-to-noise ratio (SNR), ASL fMRI provides a more interpretable measure of cerebral vasoreactivity than BOLD fMRI. Still, ASL suffers from a low SNR and is hampered by a large amount of physiological noise. The current contribution aims at improving the re- covery of the vasoreactive component from the ASL signal. To this end, a Bayesian hierarchical model is proposed, enabling the recovery of per- fusion levels as well as fitting their dynamics. On a single-subject ASL real data set involving perfusion changes induced by hypercapnia, the approach is compared with a classical GLM-based analysis. A better goodness-of-fit is achieved, especially in the transitions between baseline and hypercapnia periods. Also, perfusion levels are recovered with higher sensitivity and show a better contrast between gray- and white matter
Estimation of fuel cell operating time for prédictive maintenance strategies

International audienceOne of the limiting factors for the spreading of the fuel cell technology is the durability and researches to extend their lifetime are being done world-widely. We present here a pattern recognition approach aiming to estimate fuel cell operating time based on electrochemical impedance spectroscopy measurements. It consists in first extracting features from the impedance spectrum. For that purpose, two approaches have been investigated. In the first one, particular points of the spectrum are empirically extracted as features. In the second approach, a parametric modelling is performed to extract features from both the real and the imaginary parts of the impedance spectrum. In particular, a latent regression model is used to automatically split the spectrum into several segments that are approximated by polynomials. The number of segments is adjusted taking account the a priori knowledge about the physical behaviour of fuel cell components. Then, a linear regression model using different subsets of extracted features is employed for the estimation of fuel cell operating time. The performances of the proposed approach are evaluated on experimental data set to show its feasibility. Being able to estimate the fuel cell operating time, and consequently its remaining duration life, these results could lead to interesting perspectives for predictive maintenance policy of fuel cells
On the origin of the quasi-perpendicular ion foreshock: Full-particle simulations

International audienceMany space missions have already evidenced the existence of the ion foreshock region located upstream of the Earth's bow shock and populated by energetic backstreaming ions reflected by the shock front. In order to analyse this region, a curved shock is simulated with a 2-D particle-in-cell (PIC) code. The analysis is presently restricted to the quasi-perpendicular angular range defined by 45° ≤ θBn ≤ 90°. In agreement with experimental data, present results evidence two distinct ion populations back-streaming from the shock front along the interplanetary magnetic field: (i) the Field-Aligned Beam population (hereafter "FAB") and (ii) the gyrophase bunched population (hereafter "GPB") which differ from each other by their gyrotropic or non-gyrotropic behavior, respectively. Excluded by a simulation time which is too short, ion instabilities pitch-angle scattering cannot be the source of "GPB". Two new criteria are proposed to identify more precisely each population: their interaction time Δtint with the shock front and their downstream penetration depth. These criteria show that (i) the "FAB" population moves back and forth between the upstream edge of the shock front and the overshoot, and is characterized by a Δtint covering several upstream gyro-periods. (ii) In contrast, the "GPB" ions suffer a short interaction time (i.e. 1 < τci). We observe that the "FAB" ions may have different originsalthough all "GPB" ions seem to be produced by the electrostatic field built up at the shock and are emitted in a burst-like mode rather than in continuous way
Rheological and geodynamic controls on the mechanisms of subduction and HP/UHP exhumation of crustal rocks during continental collision: Insights from numerical models

International audienceWhile subduction of crustal rocks is increasingly accepted as a common scenario inherent to convergent processes involving continental plates and micro-continents, its occurrence in each particular context, as well as its specific mechanisms and conditions is still debated. The presence of ultra-high pressure(UHP) terranes is often interpreted as a strong evidence for continental subduction (subduction of continental crust) since the latter is seen as the most viable mechanism of their burial to UHP depths, yet if one admits nearly lithostatic pressure conditions in the subduction interface (or "channel"). The presumed links of continental subduction to exhumation of high- and ultra-high-pressure (HP/UHP) units also remain a subject of controversy despite the fact that recent physically consistent thermo-mechanical numerical models of convergent processes suggest that subduction can create specific mechanisms for UHP exhumation. We hence review and explore possible scenarios of subduction of continental crust, and their relation to exhumation of HP and UHP rocks as inferred from last generation of thermo-mechanical numerical models accounting for thermo-rheological complexity and structural diversity of the continental lithosphere. The inferences from these models are matched with the petrology data, in particular, with P-T-t paths, allowing for better understanding of subtleties of both subduction and burial/exhumation mechanisms. Numerical models suggest that exhumation and continental subduction are widespread but usually transient processes that last for less than 5-10 Myr, while long-lasting (> 10-15 Myr) subduction can take place only in rare cases of fast convergence of cold strong lithospheres (e.g. India). The models also show that tectonic heritage can play a special role in subduction/exhumation processes. In particular, when thicker continental terrains are embedded in subducting oceanic plate, exhumation of UHP terranes results in the formation of versatile metamorphic belts and domes and in series of slab roll-back and exhumation events with remarkably different P-T-t records
Preservation of an ancient grassland biomarker signature in a forest soil from the French Massif Central

International audienceIn response to the lack of studies focussing on the residence time of molecular biomarkers in soils, the lipid content of three soil profiles from the French Massif Central with different land use history were examined. The free neutral lipid content of two reference soil profiles developed under grassland and forest vegetation, and of a former grassland soil converted to forest about 60 years ago, was analysed using gas chromatography - mass spectrometry (GC-MS). Wax esters as well as the ratio of major homologues of n-alkanes and n-alkan-2-ones could be used to characterize the overlying vegetation in the reference forest and grassland soil profiles, but failed to distinguish the respective grassland and forest contributions to the profile of the soil that had changed use. For n-alkanes and n-alkan-2-ones, the failure might be attributed either to mixing of the molecular patterns inherited for the former and current plant cover, whereas for compounds such as wax esters simple degradation is likely to be involved. Conversely, iso- and anteiso- C15:0 fatty acid methyl esters (FAMEs; of bacterial origin), steroids (tracing cattle faecal contamination), tricyclic diterpenoids and their oxygenated derivatives, as well as methoxyserratenes (inherited from Pinaceae) and triterpenyl acetates (specific to the Asteraceae), proved to be effective in distinguishing current land use for the reference soil profilesand for the converted soil. The persistence of these compounds in the changed use soil allowed us to estimate their residence time in soil
Relative Gravity Measurement Campaign during the 8th International Comparison of Absolute Gravimeters (2009)

International audienceThe 8th International Comparison of Absolute Gravimeters (ICAG-2009) and the associated Relative Gravity Campaign (RGC2009) took place at the Bureau International des Poids et Mesures (BIPM) between July and October 2009. Altogether 24 institutes with 22 absolute gravimeters and 9 relative gravimeters participated in the ICAG/RGC campaign. Accurate absolute and relative gravity measurements as well as precision levelling measurements were performed on the micro-gravity 3D-grid at the BIPM. The 2009 comparison was the first to be organized as a Comité International des Poids et Mesures (CIPM) metrological Key Comparison under the CIPM MRA (Mutual Recognition Arrangement), which means that the result will be officially recognized by the governmental organizations responsible. As a consequence, the relative gravimeters employed were carefully selected and the measurement schedules were rigorously enforced compared to earlier campaigns. Thus the quality of the RGC2009 and the determination of the BIPM local gravity network were improved. After thirty years and eight successive ICAGs, the BIPM has decided to transfer its role to the National Metrological Institutes, although the CIPM will continue to organize the key comparison as ICAGs. The background to the RGC2009, and the organization, data processing and final results of the gravity and vertical gravity gradients are presented in this paper. This report is more detailed than previous final reports of the RGCs
Subduction interface processes recorded by eclogite-facies shear zones (Monviso, W. Alps)

International audienceThe Monviso ophiolite Lago Superiore Unit constitutes a well-preserved, almost continuous upper fragment of oceanic lithosphere subducted at c. 80 km depth, thereby providing a unique opportunity to study mechanical coupling processes and meter-scale fluid-rock interactions occurring at such depths in present-day subduction zones. It is made of (i) a variably thick (50-500 m) section of eclogitized basaltic crust (associated with minor calcschist lenses) overlying a 100-400 m thick metagabbroic body and of (ii) a c. 1 km thick serpentinite sole. We herein focus on the three major eclogite-facies shear zones found at the top of the unit, at the boundary between basalts and gabbros, and between gabbros and serpentinites, respectively. Strain localization occurred at lithological interfaces, irrespective of material strength. While ductile deformation dominates along the shear zones, local brittle behaviour is demonstrated by the existence of numerous eclogite breccias of Fe-Ti metagabbros and widespread garnet fractures, possibly linked with intermediate-depth eclogite-facies (micro)seismicity. These m- to hm-sized fragments of Fe-Ti metagabbros were later sheared and disseminated within serpentinite schists along the gabbro-serpentinite boundary (Lower Shear zone; LSZ). Pervasive and focused fluid flow is attested in the LSZ by significant alteration of bulk rock compositions, weakening of the rocks and widespread crystallization of hydrous parageneses. By contrast, the Intermediate Shear zone (ISZ) shows evidence for more restricted, short-range fluid flow. The activity of both the ISZ and LSZ ceased during early lawsonite eclogite-facies exhumation, when deformation localized deeper within the serpentinite sole, allowing for the detachment (and preservation) of this large ophiolitic fragment
Limits on chemical complexity in diffuse clouds: search for CH3OH and HC5N absorption

International audienceContext: An unexpectedly complex polyatomic chemistry exists in diffuse clouds, allowing detection of species such as C2H, C3H2, H2CO, and NH3, which have relative abundances that are strikingly similar to those inferred toward the dark cloud TMC-1. Aims: We probe the limits of complexity of diffuse cloud polyatomic chemistry. Methods: We used the IRAM Plateau de Bure Interferometer to search for galactic absorption from low-lying J = 2-1 rotational transitions of A- and E-CH3OH near 96.740 GHz and used the VLA to search for the J = 8-7 transition of HC5N at 21.3 GHz. Results: Neither CH3OH nor HC5N were detected at column densities well below those of all polyatomics known in diffuse clouds and somewhat below the levels expected from comparison with TMC-1. The HCN/HC5N ratio is at least 3-10 times higher in diffuse gas than toward TMC-1. Based on observations obtained with the IRAM Plateau de Bure Interferometer and the NRAO VLA telescope
The polar wind of the fast rotating Be star Achernar: VINCI/VLTI interferometric observations of an elongated polar envelope

10 pages, 5 figures, accepté par A&AInternational audienceBe stars show evidence of mass loss and circumstellar envelopes (CSE), from UV resonance lines, near-IR excesses and the presence of episodic hydrogen emission lines. The geometry of these envelopes is still uncertain, though it is often assumed that they are formed by a disk around the stellar equator and a hot polar wind. We probe the close environment of the fast rotating Be star Achernar at angular scales of a few mas in the infrared, in order to constrain the geometry of a possible polar CSE. We obtained long-baseline interferometric observations of Achernar with the VINCI/VLTI beam combiner in the $H$ and $K$ bands, using various telescope configurations and baseline lengths with a large azimuthal coverage. The observed visibility measurements along the polar direction are significantly lower than the visibility function of the photosphere of the star alone, in particular at low spatial frequencies. This points at the presence of an asymmetric diffuse CSE elongated along the polar direction of the star. We fit to our data a simple model consisting of two components: a 2D elliptical Gaussian superimposed on a uniform ellipse representing the distorted photosphere of the fast rotating star. We clearly detect a CSE elongated along the polar axis of the star, as well as the rotational flattening of the stellar photosphere. The relative near-IR flux measured for the CSE compared to the stellar photosphere is 5\%. Its angular dimensions are loosely constrained by the available data$2.7 \pm 1.3$ mas and $17.6 \pm 4.9$ mas. This CSE could be linked to free-free emission from the radiative pressure driven wind originating from the hot polar caps of the star
Potential of the Cross Biaxial Test for Anisotropy Characterization Based on Heterogeneous Strain Field

International audienceThe mechanical behavior in cross biaxial tension was investigated for two metallic sheets, an aluminium alloy and a dual phase steel. The heterogeneous strain field in the central gauge area of a cruciform specimen was analyzed by digital image correlation. Minor and major strains were output along several paths, for a given load level just before necking, showing a wide range of strain states, from uniaxial tension to biaxial state. The applied loads along the two loading directions were also recorded, the gap between the two signals being all the most important that the material anisotropy was significant. Moreover, the strain path ratio, defined as the ratio of the minor strain over the major strain, exhibited a sensible non-monotonic evolution along the transverse direction, compared to the rolling direction. Finally, a material parameter identification process with only biaxial tensile test for Bron and Besson anisotropic yield model was proposed, based on the minimization of experimental and numerical principal strains along a specified path in the gauge area of the cruciform specimen
Collision avoidance between two walkers: Role-dependent strategies

International audienceThis paper studies strategies for collision avoidance between two persons walking along crossing trajectories. It has been previously demonstrated that walkers are able to anticipate the risk of future collision and to react accordingly. The avoidance task has been described as a mutual control of the future distance of closest approach, MPD (i.e., Mininum Predicted Distance). In this paper, we studied the role of each walker in the task of controlling MPD. A specific question was: does the walker giving way (2nd at the crossing) and the one passing first set similar and coordinated strategies? To answer this question, we inspected the effect of motion adaptations on the future distance of closest approach. This analysis is relevant in the case of collision avoidance because subtle anticipatory behaviors or large last moment adaptations can finally yield the same result upon the final crossing distance. Results showed that collision avoidance is performed collaboratively and the crossing order impacts both the contribution and the strategies used: the participant giving way contributes more than the one passing first to avoid the collision. Both walkers reorient their path but the participant giving way also adapts his speed. Future work is planned to investigate the influence of crossing angle and TTC on adaptations as well as new types of interactions, such as intercepting or meeting tasks
Quantum-classical model for the surface plasmon enhanced photoemission process at metal surfaces

International audienceThe main purpose of this work is to propose a theoretical description of the surface plasmon polariton stimulated electron emission process at metal surfaces in which the primary electron ejection from the conduction band is treated quantum mechanically in order to go beyond the approximate approaches used up to now to represent this first step. Our theoretical results are well supported by experimental energy spectra obtained for some tens of femtosecond laser pulses impinging on a gold grating target at various intensities in the GW/cm 2 range. The present model which allows us to discuss various features of the surface plasmon photoemission process such as the role of the surface plasmon phase is rather simple and could be applied with slight modifications to study the stimulated photoemission of metallic nanoparticles which has been a subject of growing interest during the past few years
Modeling Uncertainty of Induced Technological Change

This paper presents a new method for modeling-induced technological learning and uncertainty in energy systems. Three related features are introduced simultaneously: (1) increasing returns to scale for the costs of new technologies; (2) clusters of linked technologies that induce learning depending on their technological "proximity" in addition to the technology relations through the structure (and connections) of the energy systems; and (3) uncertain costs of all technologies and energy sources. \ud
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The energy systems-engineering model MESSAGE developed at IIASA was modified to include these three new features. MESSAGE is a linear programming model. The starting point for this new approach was a global (single-region) energy systems version of the MESSAGE model that includes more than 100 different energy extraction, conversion, transport, distribution and end-use technologies. A new feature is that future costs of all technologies are uncertain and assumed to be distributed according to the log-normal distribution. These are stylized distribution functions that indirectly reflect the cost distributions of energy technologies in the future based on the analysis of IIASA energy technology inventory. In addition, the expected value of these cost distributions is assumed to decrease and variance assumed to narrow with the increasing application of new technologies.  This means that the process of technological learning is uncertain even as cumulative experience increases. New technologies include, for example, fuel cells, photovoltaic, and wind energy conversion technologies