pinecone/core-2020-05-10-deduplication huggingface dataset:
Inclination shallowing in Eocene Linzizong sedimentary rocks from Southern Tibet: correction, possible causes and implications for reconstructing the India-Asia collision

International audienceA systematic bias towards low palaeomagnetic inclination recorded in clastic sediments, that is, inclination shallowing, has been recognized and studied for decades. Identification, understanding and correction of this inclination shallowing are critical for palaeogeographic reconstructions, particularly those used in climatemodels and to date collisional events in convergent orogenic systems, such as those surrounding the Neotethys. Here we report palaeomagnetic inclinations from the sedimentary Eocene upper Linzizong Group of Southern Tibet that are ∼20◦ lower than conformable underlying volcanic units. At face value, the palaeomagnetic results from these sedimentary rocks suggest the southern margin of Asia was located ∼10◦N, which is inconsistent with recent reviews of the palaeolatitude of Southern Tibet. We apply two different correction methods to estimate the magnitude of inclination shallowing independently from the volcanics. The mean inclination is corrected from 20.5◦ to 40.0◦ within 95 per cent confidence limits between 33.1◦ and 49.5◦ by the elongation/inclination (E/I) correction method; an anisotropy-based inclination correction method steepens the mean inclination to 41.3 ± 3.3◦ after a curve fitting- determined particle anisotropy of 1.39 is applied. These corrected inclinations are statistically indistinguishable from the well-determined 40.3 ± 4.5o mean inclination of the underlying volcanic rocks that provides an independent check on the validity of these correction methods. Our results show that inclination shallowing in sedimentary rocks can be corrected. Careful inspection of stratigraphic variations of rock magnetic properties and remanence anisotropy suggests shallowing was caused mainly by a combination of syn- and post-depositional processes such as particle imbrication and sedimentary compaction that vary in importance throughout the section. Palaeolatitudes calculated from palaeomagnetic directions from Eocene sedimentary rocks of the upper Linzizong Group that have corrected for inclination shallowing are consistent with palaeolatitude history of the Lhasa terrane, and suggest that the India-Asia collision began at ∼20◦N by 45-55 M
A Box-Consistency Contractor Based on Extremal Functions

International audienceInterval-based methods can approximate all the real solutions of a system of equations and inequalities. The Box interval constraint propagation algorithm enforces Box consistency. Its main procedure BoxNarrow handles one function f corresponding to the revised constraint, and one variable x, replacing the other variables of f by their current intervals. This paper proposes an improved BoxNarrow procedure for narrowing the domain of x when f respects certain conditions. In particular, these conditions are fulfilled when f is polynomial. f is first symbolically rewritten into a new form g. A narrowing step is then run on the non-interval extremal functions that enclose the interval function g. The corresponding algorithm is described and validated on several numerical constraint systems
Performance Evaluations of Cryptographic Protocols Verification Tools Dealing with Algebraic Properties

International audienceThere exist several automatic verification tools of cryptographic protocols, but only few of them are able to check protocols in presence of algebraic properties. Most of these tools are dealing either with Exclusive-Or (XOR) and exponentiation properties, so-called Diffie-Hellman (DH). In the last few years, the number of these tools increased and some existing tools have been updated. Our aim is to compare their performances by analysing a selection of cryptographic protocols using XOR and DH. We compare execution time and memory consumption for different versions of the following tools OFMC, CL-Atse, Scyther, Tamarin, TA4SP, and extensions of ProVerif (XOR-ProVerif and DH-ProVerif). Our evaluation shows that in most of the cases the new versions of the tools are faster but consume more memory. We also show how the new tools: Tamarin, Scyther and TA4SP, can be compared to previous ones. We also discover and understand for the protocol IKEv2-DS a difference of modelling by the authors of different tools, which leads to different security results. Finally, for Exclusive-Or and Diffie-Hellman properties, we construct two families of protocols P xori and P dhi that allow us to clearly see for the first time the impact of the number of operators and variables in the tools' performances
On the mobility and potential retention of iodine in the Callovovian-Oxfordian formation

International audienceIodide sorption experiments were conducted on clay stone samples originating from the Callovian-Oxfordian formation under experimental conditions as close as possible to in situ conditions. The total natural iodine content of the formation is shown to be very constant throughout the formation, ranging from 2 to 3 ppm. This range is in agreement with a past iodine accumulation in the marine organic matter of the sediment before and during deposition, and early diagenesis. At variance with total iodine, the leached iodine concentrations are variable. If leached iodine is considered to represent porewater solute iodine, its concentration can be calculated and ranges from 0 (below detection limit) to ~60 µmol/L and represents 0 to 25 % of the total iodine. The reason for this variability is not understood. Sorption isotherms were determined either for natural 127I- solutions or for 131I- spiked 127I- solutions, with concentrations ranging from 10-9 to 10-3 mol/L at solid to liquid ratios from 10 to 200 g/L. No or little sorption was encountered, Kd values being in the range 0-0.5 L/kg with statistical and analytical error bands being greater than the Kd values, with the exception of one experiment at low solid to liquid ratio (10 g/L), showing significant Kd values of ~25 L/kg. In sorption experiments with natural 127I- and at the lowest added iodide concentrations (< 10-6 mol/L) an apparent negative Kd was obtained due to the iodide content in the solid porewater that was leached once the solid was suspended. The low affinity of iodide for argilite is thus confirmed. However, based only on these results and given the extent of the error bands, one cannot discard a limited iodide uptake. Literature data on iodide diffusion on similar rock materials have already shown that iodide does not behave like chloride. The retention mechanism of radio-iodide is discussed in the light of the present results and diffusion data. A model involving isotopic exchange between the natural iodine content of the geological formation and radio-iodine allows all of the results to be described. Not all the iodine in the formation appears to participate in isotopic exchange reactions with the solution. A quantification of the isotopically labile fraction of iodine would allow the effect of isotopic exchange on radio-iodide migration throughout the Callovian-Oxfordian formation to be assessed and predicted
The Role of Simulation Exercises in the Assessment of Robustness and Resilience of Private or Public Organizations

International audienceThis paper deals with the organization of simulation exercises to prepare organizations to face emergencies. The original objective of such simulations is to train people to emergency procedures and devices; we raise the question of training people to face potential crisis situations: are simulations fitted to that objective? Through the observation of a number of exercises organized by private companies and rescue services, we can answer that naïve interprettation of simulation results limits their benefits to the correction of gaps between rescribed and observed actions, without addressing complex organizational behaviour. We introduce a method to organize simulations that gives access to this complexity and to the resilience and robustness apacities of the organization by giving specific roles to observers. This method uses a model of the organization seen as a combination of three levels: structures, relations and meaning
A computational approach for the fatigue design of threaded connections

International audienceThe aim of this paper is to propose a lifetime prediction method for threaded connections. The example discussed here is a drillstring connection used in the oil and gas industry. The method is based on a mechanical analysis performed either with finite elements or a closed-form solution described in a companion paper, and a fatigue analysis using the Dang Van criterion which has been extended to finite life domain. The mechanical analysis provides the stabilized stress path and the fatigue analysis provides the fatigue life. Fatigue tests have been performed on small scale threaded connections in order to validate the methodology. The comparisons with the predictions show the difficulties to estimate the fatigue life on structures presenting high stress gradient due to scale effects
Calorimetric study of melted DNA glass

International audienceIn this work we report a detailed calorimetric study using differential scanning calorimetry (DSC) of the glassy behaviour of films made from DNA fibers. We show that after the first irreversible thermal denaturation of the molecules when the sample is reiteratively heated, it reaches a disordered state in which it presents a typical glass behaviour during successive cooling and heating scans. Furthermore, we have investigated the properties of these DNA films in two series of experiments, a slow cooling at different rates followed by a DSC scan upon heating, and ageing at a temperature below the glass transition. Introducing the fictive temperature to characterise the glass allows us to derive quantitative information on the relaxations of the DNA films, in particular to evaluate their enthalpy barrier. A comparison with similar ageing studies on PVAc highlights some specificities of the DNA samples
Does hyperpriming reveal impaired spreading of activation in schizophrenia?

International audienceEnhancement of semantic priming effects (hyperpriming) has been well documented in schizophrenic patients (Minzenberg et al. 2002). In a previous study, we demonstrated that hyperpriming was related to a more pronounced requirement to inhibit unrelated information (Lecardeur et al. 2007). On the other hand, several authors have suggested that hyperpriming could reflect enhanced spreading of semantic activation in schizophrenia (Spitzer et al. 1993; Spitzer 1997; Moritz et al. 2001). So far, there are few reports that attempted to study the spreading of activation in schizophrenic patients compared to healthy controls, when the links between semantically related information were manipulated. Notably, authors stated that activation could consequently spread farther and further in the semantic networks of schizophrenic patients. Moreover, enhanced spreading of activation was hypothesized to be responsible of the appearance of thought and language disorders in schizophrenic patients. Consequently, we examined whether the manipulation of the type of connection and the semantic distance between prime and target can modulate semantic priming effects in schizophrenic patients compared to healthy controls
How bacterial ribosomal protein L20 assembles with 23 S ribosomal RNA and its own messenger RNA.

In bacteria, the expression of ribosomal proteins is often feedback-regulated at the translational level by the binding of the protein to its own mRNA. This is the case for L20, which binds to two distinct sites of its mRNA that both resemble its binding site on 23 S rRNA. In the present work, we report an NMR analysis of the interaction between the C-terminal domain of L20 (L20C) and both its rRNA- and mRNA-binding sites. Changes in the NMR chemical shifts of the L20C backbone nuclei were used to show that the same set of residues are modified upon addition of either the rRNA or the mRNA fragments, suggesting a mimicry at the atomic level. In addition, small angle x-ray scattering experiments, performed with the rRNA fragment, demonstrated the formation of a complex made of two RNAs and two L20C molecules. A low resolution model of this complex was then calculated using (i) the rRNA/L20C structure in the 50 S context and (ii) NMR and small angle x-ray scattering results. The formation of this complex is interesting in the context of gene regulation because it suggests that translational repression could be performed by a complex of two proteins, each interacting with the two distinct L20-binding sites within the operator
Dependence of Fission-Fragment Properties On Excitation Energy For Neutron-Rich Actinides

Expérience GANIL/VAMOS/EXOGAMInternational audienceExperimental access to full isotopic fragment distributions is very important to determine the features of the fission process. However, the isotopic identification of fission fragments has been, in the past, partial and scarce. A solution based on the use of inverse kinematics to study transfer-induced fission of exotic actinides was carried out at GANIL, resulting in the first experiment accessing the full identification of a collection of fissioning systems and their corresponding fission fragment distribution. In these experiments , a 238 U beam at 6.14 AMeV impinged on a carbon target to produce fissioning systems from U to Am by transfer reactions, and Cf by fusion reactions. Isotopic fission yields of 250 Cf, 244 Cm, 240 Pu, 239 Np and 238 U are presented in this work. With this information, the average number of neutrons as a function of the atomic number of the fragments is calculated, which reflects the impact of nuclear structure around Z=50, N=80 on the production of fission fragments. The characteristics of the Super Long, Standard I, Standard II, and Standard III fission channels were extracted from fits of the fragment yields for different ranges of excitation energy. The position and contribution of the fission channels as function of excitation energy are presented
A fast tree-based method for estimating column densities  in adaptive mesh refinement codes
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Influence of UV radiation field on the structure of molecular clouds

International audienceContext. Ultraviolet radiation plays a crucial role in molecular clouds. Radiation and matter are tightly coupled and their interplay influences the physical and chemical properties of gas. In particular, modeling the radiation propagation requires calculating column densities, which can be numerically expensive in high-resolution multidimensional simulations. Aims. Developing fast methods for estimating column densities is mandatory if we are interested in the dynamical influence of the radiative transfer. In particular, we focus on the effect of the UV screening on the dynamics and on the statistical properties of molecular clouds.Methods. We have developed a tree-based method for a fast estimate of column densities, implemented in the adaptive mesh refinement code RAMSES. We performed numerical simulations using this method in order to analyze the influence of the screening on the clump formation.Results. We find that the accuracy for the extinction of the tree-based method is better than 10%, while the relative error for the column density can be much more. We describe the implementation of a method based on precalculating the geometrical terms that noticeably reduces the calculation time. To study the influence of the screening on the statistical properties of molecular clouds we present the probability distribution function of gas and the associated temperature per density bin and the mass spectra for different density thresholds.Conclusions. The tree-based method is fast and accurate enough to be used during numerical simulations since no communication is needed between CPUs when using a fully threaded tree. It is then suitable to parallel computing. We show that the screening for far UV radiation mainly affects the dense gas, thereby favoring low temperatures and affecting the fragmentation. We show that when we include the screening, more structures are formed with higher densities in comparison to the case that does not include this effect. We interpret this as the result of the shielding effect of dust, which protects the interiors of clumps from the incoming radiation, thus diminishing the temperature and changing locally the Jeans mass
Fluid trapping during capillary displacement in fractures

International audienceThe spatial distribution of fluid phases and the geometry of fluid-fluid interfaces resulting from immiscible displacement in fractures cast decisive influence on a range of macroscopic flow parameters. Most importantly, these are the relative permeabilities of the fluids as well as the macroscopic irreducible saturations. They also influence parameters for component (solute) transport, as it usually occurs through one of the fluid phase only. Here, we present a numerical investigation on the critical role of aperture variation and spatial correlation on fluid trapping and the morphology of fluid phase distributions in a geological fracture. We consider drainage in the capillary dominated regime. The correlation scale, that is, the scale over which the two facing fracture walls are matched, varies among the investigated geometries between L/256 and L (self-affine fields), L being the domain/fracture length. The aperture variability is quantified by the coefficient of variation (δ), ranging among the various geometries from 0.05 to 0.25. We use an invasion percolation based model which has been shown to properly reproduce displacement patterns observed in previous experiments. We present a quantitative analysis of the size distribution of trapped fluid clusters. We show that when the in-plane curvature is considered, the amount of trapped fluid mass first increases with increasing correlation scale Lc and then decreases as Lc further increases from some intermediate scale towards the domain length scale L. The in-plane curvature contributes to smoothening the invasion front and to dampening the entrapment of fluid clusters of a certain size range that depends on the combination of random aperture standard deviation and spatial correlation
A Tool to Estimate Land-Surface Emissivities at Microwave frequencies (TELSEM) for use in numerical weather prediction

International audienceA Tool to Estimate Land Surface Emissivities at Microwave frequencies (TELSEM) has been developed for use with the Radiative Transfer for the Television and infrared Observation satellite operational Vertical Sounder (RTTOV) model. Its objective is to provide a good estimate of the microwave surface emissivity to improve the retrieval of atmospheric profiles or the direct assimilation of radiances in numerical weather prediction (NWP) models using microwave sounder data over land. TELSEM provides emissivity estimates and error-covariance matrices for all land surfaces between 19 and 100 GHz and for all angles and linear polarizations. It is based on a pre-calculated monthly-mean emissivity climatology derived from Special Sensor Microwave/Imager (SSM/I) observations. Results show that when TELSEM is used, radiative-transfer simulations are closer to real observations. This is important when RTTOV is used to generate simulated datasets, to analyze new instrument concepts or for assimilation schemes. Experiments also show that TELSEM can be applied to provide a first guess for the surface emissivity down to 6 GHz and up to 190 GHz (extrapolating the SSM/I emissivities). These emissivities are essential for atmospheric profile retrievals over land: results for water-vapour retrieval show that surface-contaminated channels can be utilized and that the retrieval is improved, in particular for the lower troposphere. Furthermore, TELSEM emissivity first guesses can be improved in emissivity-retrieval schemes. © 2011 Royal Meteorological Society and British Crown Copyright, the Met Office
High predictive skill of global surface temperature a year ahead

International audienceWe discuss 13 real-time forecasts of global annual-mean surface temperature issued by the United Kingdom Met Office for 1 year ahead for 2000-2012. These involve statistical, and since 2008, initialized dynamical forecasts using the Met Office DePreSys system. For the period when the statistical forecast system changed little, 2000-2010, issued forecasts had a high correlation of 0.74 with observations and a root mean square error of 0.07°C. However, the HadCRUT data sets against which issued forecasts were verified were biased slightly cold, especially from 2004, because of data gaps in the strongly warming Arctic. This observational cold bias was mainly responsible for a statistically significant warm bias in the 2000-2010 forecasts of 0.06°C. Climate forcing data sets used in the statistical method, and verification data, have recently been modified, increasing hindcast correlation skill to 0.80 with no significant bias. Dynamical hindcasts for 2000-2011 have a similar correlation skill of 0.78 and skillfully hindcast annual mean spatial global surface temperature patterns. Such skill indicates that we have a good understanding of the main factors influencing global mean surface temperature. Key Points High skill of predictions, 2000-2011 Even higher skill is potentially possible Coupled model hindcasts have at least this skill over same period ©2013. American Geophysical Union. All Rights Reserved
Strain-induced magma degassing: insights from simple-shear experiments on bubble bearing melts

International audienceExperiments have been performed to determine the effect of deformation on degassing of bubble-bearing melts. Cylindrical specimens of phonolitic composition, initial water content of 1.5 wt.% and 2 vol.% bubbles, have been deformed in simple-shear (torsional configuration) in an internally heated Paterson-type pressure vessel at temperatures of 798-848 K, 100-180 MPa confining pressure and different final strains. Micro-structural analyses of the samples before and after deformation have been performed in two and three dimensions using optical microscopy, a nanotomography machine and synchrotron tomography. The water content of the glasses before and after deformation has been measured using Fourier Transform Infrared Spectroscopy (FTIR). In samples strained up to a total of γ ∼ 2 the bubbles record accurately the total strain, whereas at higher strains (γ ∼ 10) the bubbles become very flattened and elongate in the direction of shear. The residual water content of the glasses remains constant up to a strain of γ ∼ 2 and then decreases to about 0.2 wt.% at γ ∼ 10. Results show that strain enhances bubble coalescence and degassing even at low bubble volume-fractions. Noticeably, deformation produced a strongly water under-saturated melt. This suggests that degassing may occur at great depths in the volcanic conduit and may force the magma to become super-cooled early during ascent to the Earth's surface potentially contributing to the genesis of obsidian
EBSD investigation of SiC for HTR fuel particles

Xavier Bourrat : Present Address ISTO - CNRS-Université d'OrléansInternational audienceElectron back-scattering diffraction (EBSD) can be successfully performed on SiC coatings for HTR fuel particles. EBSD grain maps obtained from thick and thin unirradiated samples are presented, along with pole figures showing textures and a chart showing the distribution of grain aspect ratios. This information is of great interest, and contributes to improving the process parameters and ensuring the reproducibility of coating