pinecone/core-2020-05-10-deduplication huggingface dataset:
Dynamic crack propagation with a variational phase-field model: limiting speed, crack branching and velocity-toughening mechanisms

International audienceWe address the simulation of dynamic crack propagation in brittle materials using a regularized phase-field description, which can also be interpreted as a damage-gradient model. Benefiting from a variational framework, the dynamic evolution of the mechanical fields are obtained as a succession of energy minimizations. We investigate the capacity of such a simple model to reproduce specific experimental features of dynamic in-plane fracture. These include the crack branching phenomenon as well as the existence of a limiting crack velocity below the Rayleigh wave speed for mode I propagation. Numerical results show that, when a crack accelerates , the damaged band tends to widen in a direction perpendicular to the propagation direction, before forming two distinct macroscopic branches. This transition from a single crack propagation to a branched configuration is described by a well-defined master-curve of the apparent fracture energy Γ as an increasing function of the crack velocity. This Γ(v) relationship can be associated, from a macroscopic point of view, with the well-known velocity-toughening mechanism. These results also support the existence of a critical value of the energy release rate associated with branching: a critical value of approximately 2Gc is observed i.e. the fracture energy contribution of two crack tips. Finally, our work demonstrates the efficiency of the phase-field approach to simulate crack propagation dynamics interacting with heterogeneities, revealing the complex interplay between heterogeneity patterns and branching mechanisms
Emotional specificities of autobiographical memory after breast cancer diagnosis

International audienceCancer involves stressful events. One aspect of cognition that is impacted by stress is episodic autobiographical memory (EAM). EAM is intimately linked to self-representation. Some studies have revealed impairment of EAM in patients with breast cancer in remission. Yet, these studies failed to differentiate between the influence of adjuvant treatments and that of psychosocial factors. We therefore assessed the psychological impact of breast cancer diagnosis on EAM and self-representation profiles prior to any adjuvant treatment. Patients newly diagnosed with breast cancer (n=31) and women without any history of cancer (n=49) were compared on state anxiety, EAM and its emotional characteristics, and self-representations. The most anxious patients retrieved fewer emotional details for memories than the controls, and had lower self-representation scores than the least anxious patients, who had no deficits in emotional detail retrieval. Our results revealed distinct EAM profiles for patients, reflecting two contrasting modes of coping with breast cancer
Domain decomposition for implicit solvation models

International audienceThis article is the first of a series of papers dealing with domain decomposition algorithms for implicit solvent models. We show that, in the framework of the COSMO model, with van der Waals molecular cavities and classical charge distributions, the electrostatic energy contribution to the solvation energy, usually computed by solving an integral equation on the whole surface of the molecular cavity, can be computed more efficiently by using an integral equation formulation of Schwarz's domain decomposition method for boundary value problems. In addition, the so-obtained potential energy surface is smooth, which is a critical property to perform geometry optimization and molecular dynamics simulations. The purpose of this first article is to detail the methodology, set up the theoretical foundations of the approach, and study the accuracies and convergence rates of the resulting algorithms. The full efficiency of the method and its applicability to large molecular systems of biological interest is demonstrated elsewhere
Elastic-wave identification of penetrable obstacles using shape-material sensitivity framework

This study deals with elastic-wave identification of discrete heterogeneities (inclusions) in an otherwise homogeneous ``reference'' solid from limited-aperture waveform measurements taken on its surface. On adopting the boundary integral equation (BIE) framework for elastodynamic scattering, the inverse query is cast as a minimization problem involving experimental observations and their simulations for a trial inclusion that is defined through its boundary, elastic moduli, and mass density. For an optimal performance of the gradient-based search methods suited to solve the problem, explicit expressions for the shape (i.e. boundary) and material sensitivities of the misfit functional are obtained via the adjoint field approach and direct differentiation of the governing BIEs. Making use of the message-passing interface, the proposed sensitivity formulas are implemented in a data-parallel code and integrated into a nonlinear optimization framework based on the direct BIE method and an augmented Lagrangian whose inequality constraints are employed to avoid solving forward scattering problems for physically inadmissible (or overly distorted) trial inclusion configurations. Numerical results for the reconstruction of an ellipsoidal defect in a semi-infinite solid show the effectiveness of the proposed shape-material sensitivity formulation, which constitutes an essential computational component of the defect identification algorithm
Residual strain and piezoelectric effects in passivated GaAs/AlGaAs core-shell nanowires

International audienceWe observe a systematic red shift of the band-edge of passivated GaAs/Al0.35Ga0.65As core-shell nanowires with increasing shell thickness up to 100 nm. The shift is detected both in emission and absorption experiments, reaching values up to 14 meV for the thickest shell nanowires. Part of this red shift is accounted for by the small tensile strain imposed to the GaAs core by the AlGaAs shell, in line with theoretical calculations. An additional contribution to this red shift arises from axial piezoelectric fields which develop inside the nanowire core due to Al fluctuations in the shell
Eurocode 8-compatible synthetic time-series as input to dynamic analysis

International audienceNonlinear dynamic analysis of existing or planned structures often requires the use of accelerograms that match a target design spectrum. Here, our main concern is to generate a set of motions with a good level of fit to the Eurocode 8 (EC8) design spectra for France. Synthetic time series are generated by means of a non-stationary stochastic method. To calibrate the input parameters in the stochastic approach, we select a reference set of accelerograms for a Eurocode 8 type B site category from the PEER Ground-Motion Database, which are then adjusted to the target spectrum through wavelet addition. Then, we compute nonlinear seismic responses of a soil column, including pore pressure effects, and brittle and ductile structures to the stochastic time-series, the natural accelerograms and timeseries generated using stationary stochastic approaches. The results of these calculations reveal considerable variability in response despite the similarities in terms of spectral acceleration
The Obsessive-Compulsive Symptom (OCS) scale of the Child Behavior Checklist: A comparison between Swedish children with Obsessive-Compulsive Disorder from a specialized unit, regular outpatients and a school sample

-To evaluate the discriminative power of various items as reported by parents in the OCS-scale extracted from the Child Behavior Checklist (CBCL) problem scale and to compare findings with outcomes of previous validation studies.

Children referred to a specialized child psychiatric Obsessive-Compulsive Disorder (OCD) clinic (OCD group) (n = 185) receiving a formal OCD diagnosis according to DSM IV criteria based on interviews with the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS) were compared to a sample recruited from regular child and adolescent psychiatric outpatient clinics (CPO group) (n = 177). Both samples were compared to a normative school sample (SS group) and all three groups were matched for age and gender.

Thirty seven CBCL items, mostly representing core internalizing symptoms and parts of the thought problem scale as well as physical and sleep problems, were first identified. Ten of these items (including all discriminative items in previous validation studies) could distinguish children with OCD from CPO patients. In a subsequent analysis, the results of a logistic regression showed that four CBCL items, “Obsessions,” “Fearful and Anxious,” “Compulsions,” and “Worries” remained significant predictors. These four OCS items and previously used CBCL OCS-scales were further examined by means of ROC-analysis showing that the “Obsessions” and “Compulsions” CBCL items were the strongest predictors.

These two CBCL items performed well as screens for OCS symptoms in children and adolescents and the addition of similar CBCL items did not further increase sensitivity or specificity. It is suggested that parental responses on these two items could preferably be used as screen for OCD in children and adolescents in regular child psychiatric clinics
High-pressure structural study of yttrium monochalcogenides from experiment and theory

High-pressure powder x-ray diffraction experiments using synchrotron radiation are performed on the yttrium monochalcogenides YS, YSe, and YTe up to a maximum pressure of 23 GPa. The ambient NaCl structure is stable throughout the pressure range covered. The bulk moduli are determined to be 93, 82, and 67 GPa for YS, YSe, and YTe, respectively. First-principles total energy calculations are carried out using the full-potential linear muffin-tin orbital method. The calculated and measured lattice constants and bulk moduli are in good agrement. Under applied pressure, the yttrium monochalcogenides are predicted to undergo a structural transition. Assuming that the high-pressure phase corresponds to the CsCl crystal structure, transition pressures of 53, 36, and 14 GPa are found for YS, YSe, and YTe, respectively
Severe hematologic complications after lung transplantation in patients with telomerase complex mutations

International audienceBACKGROUND: Mutations in the telomerase complex (TERT and TR) are associated with pulmonary fibrosis and frequent hematologic manifestations. The aim of this study was to characterize the prognosis of lung transplantation in patients with TERT or TR mutations. METHODS: Patients with documented TERT or TR mutations who received a lung transplant between 2007 and 2013 in France were identified via an exhaustive search of the lung transplantation network, one expert genetic laboratory, and the clinical research network on rare pulmonary diseases. RESULTS: There were 9 patients (7 men) with TERT (n = 6) or TR (n = 3) mutations who received a single (n = 8) or a double (n = 1) lung transplant for pulmonary fibrosis. Median age was 50 years (range, 35-61 years) at diagnosis and 52 years (range, 37-62 years) at the time of lung transplantation. Thrombocytopenia was present in 7 patients before lung transplantation. After lung transplantation, 6 patients developed myelodysplasia and/or bone marrow failure, directly contributing to death in 4 cases. Anemia was observed in 9 patients, and neutropenia was observed in 3 patients. The median survival after lung transplantation was 214 days (range, 59-1,709 days). CONCLUSIONS: Patients with mutations of the telomerase complex are at high risk of severe hematologic complications after lung transplantation, in particular, bone marrow failure. Specific recommendations should be developed for appropriate guidance regarding hematologic risk assessment before transplantation and management of the post-transplantation immunosuppressive regimen
Evolution study of the Baeyer-Villiger monooxygenases enzyme family: functional importance of the highly conserved residues.

International audienceBaeyer-Villiger monooxygenases (BVMOs) catalyze the transformation of linear and cyclic ketones into their corresponding esters and lactones by introducing an oxygen atom into a C-C bond. This bioreaction has numerous advantages compared to its chemical version; it does not induce the use of potentially harmful reagents (i.e., green chemistry) and displays significant better enantio- and regio-selectivity. New potential BVMOs were searched using sequence homology for type I BVMO proteins. 116 new sequences were identified as new putative BVMOs respecting the defined selection criteria. Multiple sequence alignments were carried out on the selected sequences to study the conservation of structurally and/or functionally important amino acids during evolution. Type I BVMO signature motif was found to be conserved in 94.8% of the sequences. We noticed also the highly conserved - but previously unnoticed - Threonine 167 (93.1%), located in the signature motif; this position could be added in the pattern used to characterize specific Type I enzymes. Amino acids at the vicinity of the FAD and NADPH cofactors were found also to be highly conserved and the details of the interactions were emphasized. Interestingly, residues at the enzyme binding site were found less conserved in terms of sequence evolution, leading sometimes to some important amino acid changes. These behaviors could explain the enzyme selectivity and specificity for different ligands
Gradient schemes for two-phase flow in heterogeneous porous media and Richards equation

The gradient scheme family, which includes the conforming and mixed finite elements as well as the mimetic mixed hybrid family, is used for the approximation of Richards equation and the two-phase flow problem in heterogeneous porous media. We prove the convergence of the approximate saturation and of the approximate pressures and approximate pressure gradients thanks to monotony and compactness arguments under an assumption of non-degeneracy of the phase relative permeabilities. Strong convergence results stem from the convergence of the norms of the gradients of pressures, which demand handling the nonlinear time term. Numerical results show the efficiency on these problems of a particular gradient scheme, called the Vertex Approximate Gradient scheme
Limits to the sensitivity of a low noise compact atomic gravimeter

30 pages, 14 figuresInternational audienceA detailed analysis of the most relevant sources of phase noise in an atomic interferometer is carried out, both theoretically and experimentally. Even a short interrogation time of 100 ms allows our cold atom gravimeter to reach an excellent short term sensitivity to acceleration of $1.4\times 10^{-8}$g at 1s. This result relies on the combination of a low phase noise laser system, efficient detection scheme and good shielding from vibrations. In particular, we describe a simple and robust technique of vibration compensation, which is based on correcting the interferometer signal by using the AC acceleration signal measured by a low noise seismometer
An a Posteriori Error Estimation for the Discrete Duality Finite Volume Discretization of the Stokes Equations

International audienceWe derive an a posteriori error estimation for the discrete duality finite volume (DDFV) discretization of the stationary Stokes equations on very general twodimensional meshes, when a penalty term is added in the incompressibility equation to stabilize the variational formulation. Two different estimators are provided: one for the error on the velocity and one for the error on the pressure. They both include a contribution related to the error due to the stabilization of the scheme, and a contribution due to the discretization itself. The estimators are globally upper as well as locally lower bounds for the errors of the DDFV discretization. They are fully computable as soon as a lower bound for the inf-sup constant is available. Numerical experiments illustrate the theoretical results and we especially consider the influence of the penalty parameter on the error for a fixed mesh and also of the mesh size for a fixed value of the penalty parameter. A global error reducing strategy that mixes the decrease of the penalty parameter and adaptive mesh refinement is described
Probabilistic Atlas and Geometric Variability Estimation to Drive Tissue Segmentation

International audienceComputerized anatomical atlases play an important role in medical image analysis. While an atlas usually refers to a standard or mean image also called template, that presumably represents well a given population, it is not enough to characterize the observed population in detail. A template image should be learned jointly with the geometric variability of the shapes represented in the observations. These two quantities will in the sequel form the atlas of the corresponding population. The geometric variability is modelled as deformations of the template image so that it fits the observations. In this paper, we provide a detailed analysis of a new generative statistical model based on dense deformable templates that represents several tissue types observed in medical images. Our atlas contains both an estimation of probability maps of each tissue (called class) and the deformation metric. We use a stochastic algorithm for the estimation of the probabilistic atlas given a dataset. This atlas is then used for atlas-based segmentation method to segment the new images. Experiments are shown on brain T1 MRI datasets
High rectifying behavior in Al/Sinanocrystal-embedded SiOxNy/p-Si heterojunctions

5International audienceWe examine the electrical properties of MIS devices made of Al/Si nanocrystal-SiOxNy/p Si. The J V characteristics of the devices present a high rectifying behavior. Temperature measurements show that the forward current is thermally activated following the thermal diffusion model of carriers. At low reverse bias, the current is governed by thermal emission amplified by Poole-Frenkel effect of carriers from defects located in the silicon nanocrystals/SiOxNy interfaces, whereas tunnel conduction in silicon oxynitride matrix dominates at high reverse bias. Devices exhibit a rectification ratio >104 for the current measured at V=  1V. Study reveals that thermal annealing in forming gas (H2/N2) improves electrical properties of the devices due to the passivation of defects
Linear analysis of the influence of FIR feedback filters on the response of the pulsed digital oscillator

The original publication is available at www.springerlink.comThe objective of this work is to extend the linear analysis of PulsedDigitalOscillators to those topologies having a Finite Impulse Response (FIR) in the feedback loop of the circuit. It will be shown with two specific examples how the overall response of the oscillator can be adjusted to some point by changing the feedback filter, when the resonator presents heavy damping losses. Extensive discrete-time simulations and experimental results obtained with a MEMS cantilever with thermoelectric actuation and piezoresistive position sensing are presented. It will be experimentally shown that the performance of the oscillator is good even below the Nyquist limit
An experiment of muon radiography at Mt Etna (Italy)

International audienceInteractions of conduit geometry with gas–liquid flows control volcanic activity, implying that the evaluation of volcanic hazards requires quantitative understanding of the inner structure of the volcano. The more established geophysical imaging techniques suffer from inherent ambiguity, may require spatially dense measurements in active areas and may not provide sufficient spatial resolution in the uppermost part of the conduit system. It is thus desirable to develop new imaging techniques allowing a better spatial resolution of a volcano's upper feeding system, with reduced ambiguity and a low level of risk for operators. Muon particles can be utilized to image the internal density distribution of volcanic structures. The principle of muon radiography is essentially the same as X-ray radiography, except for substituting penetrating particles in place of photons. Muons are more attenuated by higher density parts inside the target and thus information about its inner structure are obtained from the differential muon absorption. We report on a muon-imaging experiment that was conducted at Mt Etna in 2010. The target structure was one of the summit craters of the volcano. This experiment was performed using a muon telescope suitably designed to withstand the harsh conditions in the summit zone of a high volcano. We found a marked difference between synthetic and observed attenuation of muons through the target. This discrepancy is likely due to the bias on the observed flux, arising from false muon tracks. They are caused by low-energy particles that, by chance, hit simultaneously the two matrixes of the telescope, leading to detection of a false positive. We separated the useful from the unwanted signal through a first-order model of the background noise. The resulting signal is compared with the corresponding synthetic flux. Eventually, we found regions of higher-and lower-than-expected muon flux, that are possibly related to inner features of the target crater
From sedimentary records to sediment budgets: Multiple approaches to catchment sediment flux

International audienceThis paper reviews the traditional approach to sediment budget studies in geomorphology, new approaches and more specifically the potential impact of new methodological advances. Each component of the budget is discussed including the spatial and volumetric estimations of erosion, deposition and storage and the precision and accuracy of flux rate estimation. Examples are used from recent work in Germany, The Netherlands and the UK and include the pedogenic approach to erosion estimation, remote sensing (LiDAR), geophysics and sediment-based dating techniques for flux rate estimation. The precision and accuracy of catchment sediment flux estimates based upon sediment storage is not only dependant upon volumetric accuracy but also on the precision and accuracy of sediment dating. In this area there has been a revolution with direct sediment dating techniques (TL, OSL, ESR) freeing budget studies from the constraints and biases of radiocarbon. Of particular importance is the use of cosmogenic nuclides for dating but which can also be used to derive long-term erosion rates but only using a steady state assumption. Finally a tentative initial application of the sediment budget approach to Pleistocene terrace staircase in unglaciated basins is discussed. It is argued that only now do we have the techniques available to be able to produce accurate sediment budget estimations at spatial scales greater than that of zero order basins and over time periods greater than that covered by direct observations