Démarche d'analyse spectrale en vue d'une interprétation automatique, application à un signal d'engrenages

Cet article décrit une démarche complète d'analyse spectrale commune à des experts du signal et du domaine concerné (acoustique, mécanique vibratoire) dans le but d'estimer un contenu spectral. L'originalité réside dans le processus de décision qui est fondé sur une confrontation de méthodes (Fourier, Maximum de Vraisemblance, paramétriques, déflation) couplée à une interprétation spectrale. Une pré-analyse consiste à évaluer certaines propriétés du signal (stationnarité, hypothèse gaussienne) et à étudier son autocorrélation. Ensuite, une démarche est construite à partir d'une succession d'analyses spectrales, aboutissant à la détection et à l'identification des différents motifs spectraux. L'interprétation de chaque étape est facilitée par la mise en place de critères objectifs. Enfin des analyses complémentaires sont envisagées (cyclostationnarité, recherche d'harmoniques)

Cyclostationnarités d'ordre 1 et 2 : application à des signaux vibratoires d'engrenages

Le diagnostic précoce des pannes des engrenages fait, en particulier, appel aux caractéristiques cyclostationnaires du signal vibratoire. La cyclostationarité d'un signal se manifeste sur les propriétés moyennes (ordre 1) et sur les propriétés énergétiques (ordre 2) du signal. Nous montrons l'importance de la prise en compte de ces 2 ordres de cyclostationarité pour l'analyse du signal et pour l'estimation de la corrélation spectrale. Nous appliquons cette nouvelle méthode de caractérisation à un signal vibratoire d'engrenage. L'exploitation complète des propriétés cyclostationnaires d'ordre 1 et 2 apporte de nouveaux moyens de diagnostic

SNP genotyping in melons: genetic variation, population structure, and linkage disequilibrium

Novel sequencing technologies were recently used to generate sequences from multiple melon (Cucumis melo L.) genotypes, enabling the in silico identification of large single nucleotide polymorphism (SNP) collections. In order to optimize the use of these markers, SNP validation and large-scale genotyping are necessary. In this paper, we present the first validated design for a genotyping array with 768 SNPs that are evenly distributed throughout the melon genome. This customized Illumina GoldenGate assay was used to genotype a collection of 74 accessions, representing most of the botanical groups of the species. Of the assayed loci, 91 % were successfully genotyped. The array provided a large number of polymorphic SNPs within and across accessions. This set of SNPs detected high levels of variation in accessions from this crop’s center of origin as well as from several other areas of melon diversification. Allele distribution throughout the genome revealed regions that distinguished between the two main groups of cultivated accessions (inodorus and cantalupensis). Population structure analysis showed a subdivision into five subpopulations, reflecting the history of the crop. A considerably low level of LD was detected, which decayed rapidly within a few kilobases. Our results show that the GoldenGate assay can be used successfully for high-throughput SNP genotyping in melon. Since many of the genotyped accessions are currently being used as the parents of breeding populations in various programs, this set of mapped markers could be used for future mapping and breeding efforts.This project was carried out in the frame of the MELONOMICS project (2009–2012) of the Fundación Genoma España and with the contributions of the PLAT KKBE project PIM2010PKB-00691.Peer reviewe

Study of curtaining effect reduction methods in Inconel 718 using a plasma focused ion beam

International audienceThe curtaining effect is a common challenge in focused ion beam (FIB) surface preparation. This study investigates methods to reduce this effect during plasma FIB milling of Inconel 718 (nickel‐based superalloy). Platinum deposition, silicon mask and XeF 2 gas injection were explored as potential solutions. These methods were evaluated for two ion beam current conditions; a high ion beam intensity condition (30 kV–1 µA) and a medium one (30 kV–100 nA) and their impact on curtaining reduction and resulting cross‐section quality was assessed quantitatively thanks to topographic measurements done by atomic force microscopy (AFM). XeF 2 assistance notably improved cross‐section quality at medium current level. Pt deposition and Si mask individually mitigated the curtaining effect, with greater efficacy at 100 nA. Both methods also contributed to reducing cross‐section curvature, with the Si mask outperforming Pt deposition. However, combining Pt deposition and Si mask with XeF 2 injection led to deterioration of these protective layers and the reappearance of the curtaining effect after a quite short exposure time

PROSBOT – Model and image controlled prostatic robot

International audienceThe PROSBOT project aims to improve the clinical gesture of prostate biopsy sampling through a pedagogic simulator and a robotic assistance system. The objective of the simulator is to improve the learning curve of systematic and targeted prostate biopsy acquisition through realistic simulations of the gesture and a multitude of pedagogic modules. This paper reports the developed versions of the simulator and their evaluation. The robotic assistance system, called Apollo, is a co-manipulated robotic probe holder that aims at improving the clinical gesture through several functions, amongst which are: a) locking the probe in a target position, b) providing haptic feedback to reduce gland deformation and c) gravity compensation. Two cadaver studies have shown that the device does not negatively impact or disturb the clinical gestures (transparency), but that gravity compensation improves the ergonomics of the gesture and that the locking function helps considerably at maintaining a stable position during puncture. A clinical study is currently ongoing with the objective to prove that biopsy accuracy can be improved with the robot, both for systematic and targeted sampling. Finally, the Apollo project is in an advanced stage of industrialization and will become commercially available. The possibilities for industrialization of the simulator are currently evaluated through a follow-up study. 2015 Elsevier Masson SAS. All rights reserved

An oligo-based microarray offers novel transcriptomic approaches for the analysis of pathogen resistance and fruit quality traits in melon (Cucumis melo L.)

Background: Melon (Cucumis melo) is a horticultural specie of significant nutritional value, which belongs to the Cucurbitaceae family, whose economic importance is second only to the Solanaceae. Its small genome of approx. 450 Mb coupled to the high genetic diversity has prompted the development of genetic tools in the last decade. However, the unprecedented existence of a transcriptomic approaches in melon, highlight the importance of designing new tools for high-throughput analysis of gene expression. Results: We report the construction of an oligo-based microarray using a total of 17,510 unigenes derived from 33,418 high-quality melon ESTs. This chip is particularly enriched with genes that are expressed in fruit and during interaction with pathogens. Hybridizations for three independent experiments allowed the characterization of global gene expression profiles during fruit ripening, as well as in response to viral and fungal infections in plant cotyledons and roots, respectively. Microarray construction, statistical analyses and validation together with functional-enrichment analysis are presented in this study. Conclusion: The platform validation and enrichment analyses shown in our study indicate that this oligo-based microarray is amenable for future genetic and functional genomic studies of a wide range of experimental conditions in melon.This work was supported by grants from the Spanish Ministry of Education and Science (BIO2005/007 to A.C-D; GEN2003-20237-C06 and AGL2006-08069/AGR to M.A.A.). W.D., C.R. and D. G-I. are recipients of CRAG and "Juan de la Cierva" postdoctoral contracts from the Spanish Ministry of Education and Science. S.M-G was funded by PIV2 program (AGAUR; Generalitat de Catalunya, Spain). A.M-C and J.V. are PhD students funded by I3P program (CSIC; Spain) in A.I. C-D laboratory. A.I. C-D is funded by a HFSPO/Career Development Award (CDA2004/007). A.I. C-D is a "Ramón y Cajal" researcher from the Spanish Ministry of Education and Science