12 research outputs found
Disparity-compensated view synthesis for s3D content correction
International audienceThe production of stereoscopic 3D HD content is considerably increasing and experience in 2-view acquisition is in progress. High quality material to the audience is required but not always ensured, and correction of the stereo views may be required. This is done via disparity-compensated view synthesis. A robust method has been developed dealing with these acquisition problems that introduce discomfort (e.g hyperdivergence and hyperconvergence...) as well as those ones that may disrupt the correction itself (vertical disparity, color difference between views...). The method has three phases: a preprocessing in order to correct the stereo images and estimate features (e.g. disparity range...) over the sequence. The second (main) phase proceeds then to disparity estimation and view synthesis. Dual disparity estimation based on robust block-matching, discontinuity-preserving filtering, consistency and occlusion handling has been developed. Accurate view synthesis is carried out through disparity compensation. Disparity assessment has been introduced in order to detect and quantify errors. A post-processing deals with these errors as a fallback mode. The paper focuses on disparity estimation and view synthesis of HD images. Quality assessment of synthesized views on a large set of HD video data has proved the effectiveness of our method
A Knowledge Management Platform for Documentation of Case Reports in Pharmacovigilance
Most countries have developed information systems to report drug adverse effects. However, as in other domains where systematic reviews are needed, there is little guidance on how systematic documentation of drug adverse effects should be performed. The objective of the VigiTermes project is to develop a platform to improve documentation of pharmacovigilance case reports for the pharmaceutical industry and regulatory authorities. In order to improve systematic reviews of adverse drug reactions, we developed a prototype that first reproduces and standardizes search strategies, then extracts information from the Medline abstracts which were retrieved and annotates them. The platform aims at providing transparent access and analysis tools to pharmacovigilance experts investigating relevance of safety signals related to drugs. The platform's architecture consists in the integration of two vendor tools ITM® and Luxid® and one academic web service for knowledge extraction from medical literature. Whereas a manual search performed by a pharmacovigilance expert retrieved 578 publications, the system proposed a list of 229 publications thus decreasing time required for review by 60%. Recall was 70% and additional developments are required in order to improve exhaustivity
A Process-Structure Investigation of Aluminum Oxide and Oxycarbide Thin Films prepared by Direct Liquid Injection CVD of Dimethylaluminum Isopropoxide (DMAI)
We present the direct liquid injectionCVDof aluminum oxide and oxycarbide thin films using dimethylaluminum isopropoxide at high process temperature (500–700 8C) with the addition ofO2 gas, and at low temperature (150–300 8C) with the addition of H2O vapor. Very smooth films with typical roughness values lower than 2 nm are obtained. The thin films are composed of an amorphous material. The composition evolves as a function of temperature from that of a partial hydroxide to a stoichiometric oxide at low deposition temperature(150–300 8C), and from that of a stoichiometric oxide to a mixture of an oxide with an(oxy)carbide at higher temperature (500–700 8C)
Effects of eight neuropsychiatric copy number variants on human brain structure
Many copy number variants (CNVs) confer risk for the same range of neurodevelopmental symptoms and psychiatric conditions including autism and schizophrenia. Yet, to date neuroimaging studies have typically been carried out one mutation at a time, showing that CNVs have large effects on brain anatomy. Here, we aimed to characterize and quantify the distinct brain morphometry effects and latent dimensions across 8 neuropsychiatric CNVs. We analyzed T1-weighted MRI data from clinically and non-clinically ascertained CNV carriers (deletion/duplication) at the 1q21.1 (n = 39/28), 16p11.2 (n = 87/78), 22q11.2 (n = 75/30), and 15q11.2 (n = 72/76) loci as well as 1296 non-carriers (controls). Case-control contrasts of all examined genomic loci demonstrated effects on brain anatomy, with deletions and duplications showing mirror effects at the global and regional levels. Although CNVs mainly showed distinct brain patterns, principal component analysis (PCA) loaded subsets of CNVs on two latent brain dimensions, which explained 32 and 29% of the variance of the 8 Cohen’s d maps. The cingulate gyrus, insula, supplementary motor cortex, and cerebellum were identified by PCA and multi-view pattern learning as top regions contributing to latent dimension shared across subsets of CNVs. The large proportion of distinct CNV effects on brain morphology may explain the small neuroimaging effect sizes reported in polygenic psychiatric conditions. Nevertheless, latent gene brain morphology dimensions will help subgroup the rapidly expanding landscape of neuropsychiatric variants and dissect the heterogeneity of idiopathic conditions
Mechanism of olivine and glass alteration under experimental H2O-CO2 based supercritical gas: Application to modern and ancient Venus
International audienceExtreme conditions encountered in some geological contexts (deep serpentinization,interaction of Venus atmosphere with its basaltic surface, volcanic degassing) activate mechanismsand rates of silicate alteration that are poorly understood. In the present study, we investigate themechanisms of mineral reactions in a natural geological system at high temperature, under conditionswhere the low solvation of cations by fluids likely promotes surface reactions such as surface diffusionand/or local recrystallization. We focus on vitreous glasses and olivine, reputed to be the mostalterable phases in volcanic rocks, by reacting samples for one week in a Ni-based alloy experimentalvessel. For the framework of our experimental study, we chose to apply the deep atmosphereconditions on Venus: 470°C and 90 bar of reconstituted Venus-like gas. We also tested the effect ofwater (Early Venus or wet volcanic degassing) by adding water vapor at up to 320 bar total pressure.The mineral reactions affecting the samples were identified by a set of spectroscopic surface analysesof the altered samples: Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, X-RayDiffraction in grazing incidence mode, X-ray Photo electron Spectroscopy and Raman spectroscopy.Samples of obsidian and tholeiitic glasses are found to be sensitive to a threshold waterpressure, depending on glass composition, below which the reaction is limited to some elementalmobility in the glass (alkali enrichment, calcium loss) leading to a possibly more stable surface layerof tens to hundreds of microns. Above this threshold water pressure (ca. 50 bar H2O for the obsidianbut >250 bar H2O for the tholeiitic glass), water promotes the depolymerization of the glass and thecrystallization of stable minerals. This crystalline rim is less protective that the chemically modifiedlayer.Olivine samples react differently depending on whether the olivine is isolated or included in abasaltic rock. In the latter case only, iron coatings are formed, which are identified as hematite,suggesting that this phase is not fed by olivine itself but rather by surface diffusion from neighboringFe-rich phases. This supports the conclusions from experimental studies and orbital observations onthe short-term visibility of unaltered olivine in Venus lava flows: such a coating is enhanced when Febearingminerals are in the proximity of olivine. Under high water vapor pressure, Fe-bearing talc (andnot serpentine) forms by a likely topotactic reaction that also incorporates silica from the gas. This talclayer may form a protective layer, implying that serpentinization of ultramafic rocks at hightemperature may not be as prevalent as one might think in a gas-dominated system like the EarlyVenus surface
Project SafeFoodPack Design: case study on indirect migration from paper and boards
Migration due to indirect contact with packaging caused several major sanitary crises, including the spread contamination of dry food by mineral oils and printing ink constituents from cardboard. The issues are still not fully resolved because the mechanisms have been insufficiently described and the relationship between design, contamination level, type of contaminant, and conditions of storage (time and temperature) are poorly understood. This study proposes a forensic analysis of these phenomena when food is separated from cardboard by a plastic layer. Practical relationships and advanced simulation scenarios were devised and validated against the long-term migration between 20 and 60°C of 15 substances. They were chosen to be representative of the main contaminants of cardboard: aliphatic and aromatic mineral oils, photo-initiators and plasticisers. Data were summarised as iso-contamination curves and iso-contamination times up to 2 years. Simple rules are illustrated to extrapolate the results to arbitrary conditions in order to identify critical substances and to estimate the plastic film’s thickness to keep the contamination within acceptable limits. Recommendations for the risk management of contamination routes without contact are finally drafted
Amorphous alumina thin films deposited on titanium: Interfacial chemistry and thermal oxidation barrier properties
International audienceTi/Al2O3 bilayer stacks are used as model systems to investigate the role of atomic layer deposition (ALD) and chemical vapor deposition (CVD) to prepare 30–180 nm thick amorphous alumina films as protective barriers for the medium temperature oxidation (500–600 8C) of titanium, which is employed in aeronautic applications. X-ray diffraction (XRD), transmission electron microscopy (TEM) with selected area electron diffraction (SAED), and X-ray photoelectron spectroscopy (XPS) results show that the films produced from the direct liquid injection (DLI) CVD of aluminum tri-isopropoxide(ATI) are poor oxygen barriers. The films processed using the ALD of trimethylaluminum (TMA) show good barrier properties but an extensive intermixing with Ti which subsequently oxidizes. In contrast, the films prepared from dimethyl aluminum isopropoxide (DMAI) by CVD are excellent oxygen barriers and show little intermixing with Ti. Overall, these measurements correlate the effect of the alumina coating thickness, morphology, and stoichiometry resulting from the preparation method to the oxidation barrier properties, and show that compact and stoichiometric amorphous alumina films offer superior barrier properties