pinecone/core-2020-05-10-deduplication huggingface dataset:
Entropy and drift in word hyperbolic groups

International audienceThe fundamental inequality of Guivarc'h relates the entropy and the drift of random walks on groups. It is strict if and only if the random walk does not behave like the uniform measure on balls. We prove that, in any nonelementary hyperbolic group which is not virtually free, endowed with a word distance, the fundamental inequality is strict for symmetric measures with finite support, uniformly for measures with a given support. This answers a conjecture of S. Lalley. For admissible measures, this is proved using previous results of Ancona and Blachère-Haïssinsky-Mathieu. For non-admissible measures, this follows from a counting result, interesting in its own right: we show that, in any infinite index subgroup, the number of non-distorted points is exponentially small. The uniformity is obtained by studying the behavior of measures that degenerate towards a measure supported on an elementary subgroup
2.9 to 1.9 Ga paleoalterations ofArchean granitic basement of the Franceville basin (Gabon)

International audienceThe Archean granitoids in the Kiéné area, Gabon, are overlained by the Paleoproterozoic sediments of the Franceville basin (2.1 Ga). The basin is known for its high-grade uranium deposits among which some have been forming natural nuclear fission reactors. Most of the studies were dedicated to the FA-FB Paleoproterozoic sediments hosting these uranium deposits. Little is known on the Archean basement itself and specifically on the hydrous alteration events it experienced before and after the sediment deposition. The present work is focused on their petrographical, mineralogical and geochemical characterization. Dating the successive alteration events has been attempted on altered monazite crystals. Rocks in different alteration states have been sampled from eight drill cores crosscutting the Archean - Paleoproterozoic unconformity. The Archean granitoids observed in the deepest levels exhibit typical petrographical features of a propylitic alteration while they are intensely illitized up to the unconformity. The propylitic alteration is mainly pervasive but the original texture of the granitoïds is conserved in spite of the formation of new minerals: Mg-chlorite, allanite and epidote forming a typical paragenesis. The illitic alteration is much more invasive near the unconformity. The illitization process leads to the replacement of feldspars and the corrosion of quartz crysals by an illitic matrix while the ferromagnesian minerals are pseudomorphosed by a Fe-chlorite + phengite + hematite assemblage. The final fluid-rock interaction step is marked by fissural deposits of calcite and anhydrite. The δ13C isotopic data show that the fissural carbonates precipitated from diagenetic fluids enriched carbon products deriving from the maturation of organic matter. The U-Pb isotopic analyzes performed on monazite crystals have dated three distinct events: 3.0-2.9 Ga (magmatic), 2.6 Ga (propylitic alteration) and 1.9 Ga (diagenetic illitization). The calculation of geochemical mass balances suggests that the water-rock ratio during the propylitic alteration event was weak. On the contrary, it was much higher during the overprinted illitization which is characterized by an intense leaching of Na, Ca, Mg, Sr, REE and an enrichment in K, Rb,Cs. Neither the petrographic features nor the geochemical data militate for an Archean weathering event (paleosol). In the present case, diagenetic fluids have percolated from the unconformity into the basement where they overprinted the illitization processes upon the previously propylitized rocks. These fluids were probably oxidant as they are also responsible of the U mobilization which led to the formation of the ore deposits close to the FA-FB interface
Extending Signatures of Reputation

Part 3: Preserving PrivacyInternational audienceReputation mechanisms are a powerful tool to reduce the potential risk of interacting with almost or completely unknown users in environments in which there is no incentive to behave trustworthily, e.g. in open and large-scale systems. However, by collecting feedback about users, reputation mechanisms can easily be manipulated to deduce users' profiles; thus, these mechanisms jeopardize users' privacy, which clearly compromise their wide adoption. Privacy-preserving reputation mechanisms have recently been proposed to solve this issue. All the proposed designs either rely on a trusted central authority to handle the casting of votes and the derivation of reputation scores, or are based on a distributed environment and use cryptographic tools (e.g. non-interactive zero-knowledge proofs of knowledge and homomorphic encryption) to demonstrate the validity of votes and reputation scores. However, to the best of our knowledge, all the proposed distributed mechanisms produce solely monotonic reputation scores: whatever the outcome of an interaction, a service provider's reputation can never decrease. In this article, we propose a distributed privacy-preserving reputation mechanism handling both positive and negative votes. This is achieved by combining algorithms and tools from both the distributed and the cryptographic communities
Processing the Couette viscometry data using a Bingham approximation in shear rate calculation

The original contribution is available at http://www.sciencedirect.com/science/article/pii/S037702570800013XInternational audienceThis paper presents an approach to computing the shear flowcurve from torque-rotational velocity data in a Couette rheometer. The approximation techniques in shear rate calculation are generally dictated by the radius ratio between coaxial cylinders and the rheological behaviour of fluid tested. Here, the approach consists in analysing the sheared material as a Bingham fluid and computing an average shear rate when the fluid in the cylindrical gap is partially and fully sheared. We focus in particular on the applicability of the Bingham approximation in shear rate calculation. First, the approach is assessed by examining synthetic data generated with Newtonian, non-Newtonian and yield stress materials with known properties, varying the gap radius ratio. The results, which are compared with commonly used techniques in shear rate calculation, prove the relevance of the proposed approach. Finally, its efficiency is examined by applying it to process Couette data of yield stress fluids taken from published works
Model-driven security policy deployment: property oriented approach

International audienceWe address the issue of formally validating the deployment of access control security policies. We show how the use of a formal expression of the security requirements, related to a given system, ensures the deployment of an anomaly free abstract security policy. We also describe how to develop appropriate algorithms by using a theorem proving approach with a modeling language allowing the specification of the system, of the link between the system and the policy, and of certain target security properties. The result is a set of proved algorithms that constitute the certified technique for a reliable security policy deployment
Perspective of CO2 capture & storage (CCS) development in Vietnam: Results from expert interviews

International audienceThis paper summarizes expert opinions regarding crucial factors that mayinfluence Vietnam’s future use of carbon capture and storage (CCS) based onface-to-face interviews in December 2013 with 16 CCS-related experts fromthe Vietnamese government, research institutes, universities and the energyindustrial sector. This study finds that financial incentives and climate policyare the most important factors for the development of CCS technologies inVietnam in the next two decades. Financial incentives involve direct subsidiesfrom the government, such as tax exemptions for land use and the importationof CCS-related equipment. In addition, all the experts agree that internationalfinancial support is important to initiate a large deployment of CCStechnologies in Vietnam by implementing demonstrative/pilot projects to proveCCS’s working efficiency
Hyperdeterminantal computation for the Laughlin wave function

International audienceThe decomposition of the Laughlin wave function in the Slater orthogonal basis appears in the discussion on the second-quantized form of the Laughlin states and is straightforwardly equivalent to the decomposition of the even powers of the Vandermonde determinants in the Schur basis. Such a computation is notoriously difficult and the coefficients of the expansion have not yet been interpreted. In our paper, we give an expression of these coefficients in terms of hyperdeterminants of sparse tensors. We use this result to construct an algorithm allowing to compute one coefficient of the development without computing the others. Thanks to a program in {\tt C}, we performed the calculation for the square of the Vandermonde up to an alphabet of eleven lettres
Influence of the zinc concentration of zinc substituted hydroxyapatite on cytokines production by human monocytes in vitro

A possible complication associated with the implantation of HA-based prosthesis is the release of particles. Those particles can be phagocyted by monocytes that are among the first cells to colonize the inflammatory site. The activated monocytes produce inflammatory mediators such as cytokines that cause osteoclasts activation. The present work studies the effect of zinc-substituted hydroxyapatite particles with various concentrations of zinc on cytokines production (TNF-α, IL-1β, IL-6, IL-10, and IL-8) by human monocytes LPS-stimulated or not. The concentrations used were 0.5%, 1%, 2%, and 5%. Our data demonstrates that the zinc has an effect on cytokines production. It decreases the production of TNF- α and increases the production of IL-8 by unstimulated cells. Using LPS-stimulated cells, it decreases the production of inflammatory cytokines and increases the production of anti-inflammatory cytokine (IL-10). So zinc-substituted hydroxyapatite has favourable effects on the cytokines production by monocytes
CdCl2 treatment related diffusion phenomena in Cd1xZnxS/CdTe solar cells

Utilisation of wide bandgap Cd1_xZnxS alloys as an alternative to the CdS window layer is an attractive route to enhance the performance of CdTe thin film solar cells. For successful implementation, however, it is vital to control the composition and properties of Cd1_xZnxS through device fabrication processes involving the relatively high-temperature CdTe deposition and CdCl2 activation steps. In this study, cross-sectional scanning transmission electron microscopy and depth profiling methods were employed to investigate chemical and structural changes in CdTe/Cd1_xZnxS/CdS superstrate device structures deposited on an ITO/boro-aluminosilicate substrate. Comparison of three devices in different states of completion—fully processed (CdCl2 activated), annealed only (without CdCl2 activation), and a control (without CdCl2 activation or anneal)—revealed cation diffusion phenomena within the window layer, their effects closely coupled to the CdCl2 treatment. As a result, the initial Cd1_xZnxS/CdS bilayer structure was observed to unify into a single Cd1_xZnxS layer with an increased Cd/Zn atomic ratio; these changes defining the properties and performance of the Cd1_xZnxS/CdTe device
Phase diagram of boron-doped diamond revisited by thickness-dependent transport studies

International audienceWe report on a detailed study of the electronic properties of a series of boron-doped diamond epilayers with dopant concentrations ranging from 1.10^ 20 to 3.10^21 cm −3 and thicknesses (d ⊥) ranging from 2 µm to 8 nm. By using well-defined mesa patterns that minimize the parasitic currents induced by doping inhomogeneities, we have been able to unveil a new phase diagram differing from all previous reports. We show that the onset of superconductivity does actually not coincide with the metal-insulator transition in this system. Moreover a dimensional crossover from 3D to 2D transport properties could be induced by reducing d ⊥ in both the metallic non-superconducting and superconducting epilayers, without any reduction of Tc with d ⊥ in the latter
Mapping the discipline history of education

International audienceInaugurated in 2013, this collective research programme aims to construct an international mapping of the history of education that accounts for recent devel-opments in the field. Our goal is to create a current and retrospective assessment of the discipline's institutional grounding and of the knowledge produced by its practitioners, stretching across national and cultural borders. Ultimately, the pro-gramme will help to increase interactions among scholars and facilitate the crea-tion of collaborative research agendas, thereby augmenting the standing and visibility of the discipline. This text will briefly introduce the programme's conceptual basis, explaining the methodological steps taken to ensure the comparability of data gathered and the transnational and transcontinental character of the study's design. In the second section, we will zoom in on doctoral students' dissertations, which are the opti-mal way to study a discipline's development and potential. Doctoral students and recent graduates are part of a tradition, a school of thought, and yet they constitute that tradition's replacement and renewal. Therefore, as graduate stu-dents carry forth the disciplinary torch, they hold the future of the field in their hands
Field and angular dependence of the Sommerfeld coefficient in Al-doped MgB2 single crystals

International audienceThe angular and field dependence of the Sommerfeld coefficient = lim Cel /T T→0 Cel being the electronic contribution to the specific heat has been measured in Al-doped MgB2 single crystals for x=0, x=0.1, and x 0.2 . We show that the decomposition previously introduced to describe H, where is the angle between the applied field and the c axis in pure samples Phys. Rev. Lett. 98, 137001 2007 is well adapted to doped samples: e.g., the contribution of the band to the specific heat is proportional to B/Bc2 whereas the contribution of the band is isotropic but highly nonlinear in field. We hence present the evolution of the coherence lengths of the two bands and corresponding Fermi velocities with doping
Creating culturally sustainable agri-environmental schemes

-Evidence is emerging from across Europe that contemporary agri-environmental schemes are having only limited, if any, influence on farmers’ long-term attitudes towards the environment. In this theoretical paper we argue that these approaches are not ‘culturally sustainable’, i.e. the actions are not becoming embedded within farming cultures as part of conventional ‘good farming’ practice. We propose (following Bourdieu) that, in order to culturally embed the environmental values, beliefs and knowledges that underlie such schemes, policy-makers need to devise approaches that allow the creation of cultural and social capital within farming communities – rather than simply compensating for economic capital lost. We outline the theoretical basis of our position and discuss how the contemporary agri-environmental approach of paying for specified environmental management services restricts the ability of such schemes to generate cultural and, thereby, social capital. Finally, we outline two possible ways of accounting for cultural capital in scheme creation: either through the development of measures of cultural capital that enable its incorporation into contemporary economic models or through a major revision to the way we construct and apply agri-environmental schemes.the Foundation for Research Science and Technology, New Zealand, and the Research Council of Norway as part of the AGRIPOL project (in association with the Centre for Rural Research
Specialists in ancient trees are more affected by climate than generalists

-Ancient trees are considered one of the most important habitats for biodiversity in Europe and North America. They support exceptional numbers of specialized
species, including a range of rare and endangered wood-living insects. In this study, we use a dataset of 105 sites spanning a climatic gradient along the oak
range of Norway and Sweden to investigate the importance of temperature and precipitation on beetle species richness in ancient, hollow oak trees. We expected
that increased summer temperature would positively influence all wood-living beetle species whereas precipitation would be less important with a negligible or
negative impact. Surprisingly, only oak-specialist beetles with a northern distribution increased in species richness with temperature. Few specialist beetles and no generalist beetles responded to the rise of 4°C in summer as covered by our climatic gradient. The negative effect of precipitation affected more specialist species than did temperature, whereas the generalists remained unaffected. In summary,
we suggest that increased summer temperature is likely to benefit a few specialist beetles within this dead wood community, but a larger number of specialists are
likely to decline due to increased precipitation. In addition, generalist species will remain unaffected. To minimize adverse impacts of climate change on this important community, long-term management plans for ancient trees are important
Non-isothermal bubble rise: non-monotonic dependence of surface tension on temperature

We study the motion of a bubble driven by buoyancy and thermocapillarity in a tube with a non-uniformly heated walls, containing a so-called ‘self-rewetting fluid’; the surface tension of the latter exhibits a parabolic dependence on temperature, with a well-defined minimum. In the Stokes flow limit, we derive the conditions under which a spherical bubble can come to rest in a self-rewetting fluid whose temperature varies linearly in the vertical direction, and demonstrate that this is possible for both positive and negative temperature gradients. This is in contrast to the case of simple fluids whose surface tension decreases linearly with temperature, for which bubble motion is arrested only for negative temperature gradients. In the case of self-rewetting fluids, we propose an analytical expression for the position of bubble arrestment as a function of other dimensionless numbers. We also perform direct numerical simulation of axisymmetric bubble motion in a fluid whose temperature increases linearly with vertical distance from the bottom of the tube; this is done for a range of Bond and Galileo numbers, as well as for various parameters that govern the functional dependence of surface tension on temperature. We demonstrate that bubble motion can be reversed and then arrested only in self-rewetting fluids, and not in linear fluids, for sufficiently small Bond numbers. We also demonstrate that considerable bubble elongation is possible under significant wall confinement, and for strongly self-rewetting fluids and large Bond numbers. The mechanisms underlying the phenomena observed are elucidated by considering how the surface tension dependence on temperature affects the thermocapillary stresses in the flow
Temporal source evolution and crustal contamination at Lopevi Volcano, Vanuatu Island Arc

International audienceHere we present a new geochemical study of Lopevi volcano, one the most active volcanoes in the Vanuatu island arc. We focus on the temporally well-defined sequence of lava flows emitted since 1960, and for the first time, on pre-1960 volcanic products, including high-MgO basalts and felsic andesites, the most evolved lavas sampled so far on this island. This work reports the first Pb and Hf isotopic study of lavas from Lopevi island. These lavas display correlations between differentiation indexes such as SiO2 content and isotopic ratios. The felsic andesites extend the known correlations with both the least (Sr-Pb) and the most (Nd-Hf) radiogenic isotopic compositions on the island. Our results confirm that the rising magma interacted with the sub-arc crust. Assimilation-Fractional Crystallization (AFC) quantitative modeling of trace element ratios and isotopic compositions requires 1% and 10% of assimilated partial melts of a mafic oceanic crust to account for the pre- and post-1960 lavas, respectively. The post-1960 lavas differ from the former lavas emitted ~ 20 years earlier by enrichments in fluid mobile elements (K, Ba, Rb...), Th, and Light Rare Earth Elements (LREE). We ascribe these features to slight variations in the metasomatic agent added to the sub-arc mantle and ultimately derived from the subducted lithosphere. However, the contrasting time scales involved in subducted lithosphere dehydration and magma genesis, relative to the time elapsed between eruptions of the two lava series, suggest that two different portions of mantle which have undergone slightly different metasomatism, gave birth to the Lopevi lavas. These distinct magmas are still present beneath the volcano
Diffusion MRI abnormalities detection with orientation distribution functions: A multiple sclerosis longitudinal study

International audienceWe propose a new algorithm for the voxelwise analysis of orientation distribution functions between one image and a group of reference images. It relies on a generic framework for the comparison of diffusion probabilities on the sphere, sampled from the underlying models. We demonstrate that this method, combined to dimensionality reduction through a principal component analysis, allows for more robust detection of lesions on simulated data when compared to classical tensor-based analysis. We then demonstrate the efficiency of this pipeline on the longitudinal comparison of multiple sclerosis patients at an early stage of the disease: right after their first clinically isolated syndrome (CIS) and three months later. We demonstrate the pre-dictive value of ODF-based scores for the early detection of lesions that will appear or heal
Dark resonances as a probe for the motional state of a single ion

Single, rf-trapped ions find various applications ranging from metrology to quantum computation. High-resolution interrogation of an extremely weak transition under best observation conditions requires an ion almost at rest. To avoid line-broadening effects such as the second order Doppler effect or rf heating in the absence of laser cooling, excess micromotion has to be eliminated as far as possible. In this work the motional state of a confined three-level ion is probed, taking advantage of the high sensitivity of observed dark resonances to the trapped ion's velocity. Excess micromotion is controlled by monitoring the dark resonance contrast with varying laser beam geometry. The influence of different parameters such as the cooling laser intensity has been investigated experimentally and numerically
Identification of standing fronts in steady state fluid flows: exact and approximate solutions for propagating MHD modes

International audienceThe spatial structure of a steady state plasma flow is shaped by the standing modes with local phase velocity exactly opposite to the flow velocity. The general procedure of finding the wave vectors of all possible standing MHD modes in any given point of a stationary flow requires numerically solving an algebraic equation. We present the graphical procedure (already mentioned by some authors in the 1960's) along with the exact solution for the Alfvén mode and approximate analytic solutions for both fast and slow modes. The technique can be used to identify MHD modes in space and laboratory plasmas as well as in numerical simulations