Showing papers by "Conservatoire national des arts et métiers published in 2009"

Genomewide Association Study of an AIDS-Nonprogression Cohort Emphasizes the Role Played by HLA Genes (ANRS Genomewide Association Study 02)

Abstract: To elucidate the genetic factors predisposing to AIDS progression, we analyzed a unique cohort of 275 human immunodeficiency virus (HIV) type 1-seropositive nonprogressor patients in relation to a control group of 1352 seronegative individuals in a genomewide association study (GWAS). The strongest association was obtained for HCP5 rs2395029 (P = 6.79 × 10 −10 ; odds ratio, 3.47) andwaspossibly linkedto aneffect of sex. Interestingly, this single-nucleotide polymorphism (SNP) was in high linkage disequilibrium with HLA-B, MICB, TNF, and several other HLA locus SNPs and haplotypes. A meta-analysis of our genomic data combined with data from the previously conducted Euro-CHAVI (Center for HIV/AIDS Vaccine Immunology) GWAS confirmed the HCP5 signal (P = 3.02 × 10 −19 ) and identified several new associations, all of them involving HLA genes: MICB, TNF, RDBP, BAT1-5, PSORS1C1, and HLA-C. Finally, stratification by HCP5 rs2395029 genotypes emphasized an independent role for ZNRD1, also in the HLA locus, and this finding was confirmed by experimental data. The present study, the first GWAS of HIV-1 nonprogressors, underscores the potential for some HLA genes to control disease progression soon after infection.

Life cycle analysis of 4.5 MW and 250 W wind turbines

Abstract: Electric generation by wind turbine is growing very strongly. However, the environmental impact of wind energy is still a matter of controversy. This paper uses Life Cycle Assessment, comparing two systems: a 4.5 MW and a 250 W wind turbines, to evaluate their environmental impact. All stages of life cycle (manufacturing, transports, installation, maintenance, disassembly and disposal) have been analysed and sensitivity tests have been performed. According to the indexes (PEPBT (primary energy pay back time), CO2 emissions, etc.), the results show that wind energy is an excellent environmental solution provided first, the turbines are high efficiency ones and implemented on sites where the wind resource is good, second, components transportation should not spend too much energy and, third, recycling during decommissioning should be performed correctly. This study proves that wind energy should become one of the best ways to mitigate climate change and to provide electricity in rural zones not connected to the grid.

Clinical characteristics of a series of 302 French patients with hidradenitis suppurativa, with an analysis of factors associated with disease severity.

Abstract: Background Factors associated with the severity of hidradenitis suppurativa (HS) are not known. Objective We sought to identify factors associated with the severity of HS. Methodology The severity of disease in a series of 302 consecutive patients with HS was assessed using the Sartorius score. Results Atypical locations were more common in men than in women (47.1% vs 14.8%; P Limitations The referral center base of the study may have biased recruitment. Conclusion Our data showed a significant association between the severity of HS and several clinical and behavioral factors. Prospective studies are needed to confirm the prognostic role of these factors.

Dietary intake, physical activity and nutritional status in adults: the French nutrition and health survey (ENNS, 2006–2007)

Abstract: The French National Programme on Nutrition and Health (Programme national nutrition sante (PNNS)), the aim of which is to reduce nutrition-related chronic diseases, necessitates monitoring of nutritional characteristics. Our objective was to describe dietary intake, physical activity and nutritional status in a national sample of adults, especially according to current French recommendations. The study is based on a cross-sectional population-based survey using a multistage sampling design (Etude nationale nutrition sante (ENNS)). Between February 2006 and March 2007, 3115 18-74-year-old adults were included (participation rate 59.7 %). Energy, macronutrient and food consumption were estimated through three randomly distributed 24 h recalls, and compared to PNNS recommendations; physical activity was described using International Physical Activity Questionnaire guidelines; anthropometry, blood pressure and biochemical measurements were assessed according to national and international references. When compared to current recommendations, intake of carbohydrates (>50 % energy intake without alcohol: 26.4 %), SFA ( 25 g/d: 13.7 %) was frequently unsatisfactory. While overall consumption of 'meat, seafood and eggs' was satisfactory, that of fruits and vegetables ( > or = 400 g/d: 43.8 %) and seafood (two or more servings per week: 29.9 %) was frequently too low. The physical activity level was satisfactory at 63.2 %. Overweight was observed in 49.3 % of adults, while 30.9 % were hypertensive and 44.1 % had dyslipidaemia. Vitamin and iron-poor status was found to affect less than 10 % of the population. Based on the ENNS survey, overall nutrition remains a problem in France. Comparison of these data with those of other countries could contribute to a better understanding of variations in nutrition-related diseases.

Calixarene‐Based Fluorescent Molecular Sensors for Toxic Metals

Abstract: There is an increasing interest in the early detection of toxic metals in the environment. In this context, fluorescence is a very attractive detection method because of its intrinsic sensitivity, its response time and the possibility of imaging via fluorescence microscopy. Of the various complexing units available for the detection of toxic metal ions (chelators, open-chain structures, crown-ethers, cryptands), calixarenes offer distinct advantages in term of selectivity and the easy incorporation of a fluorophore into the structure. In this microreview, after recalling the main classes offluorescent molecular sensors based on cation-induced changes in excited-state processes (photoinduced electron- or charge-transfer, excimer formation, energy transfer), we present various calixarene-based sensors designed for the detection of caesium, mercury, lead and cadmium.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Stabilization of overweight prevalence in French children between 2000 and 2007

Abstract: Objective. Over the past several decades, the prevalence of childhood obesity has increased worldwide. In France, the National Nutrition and Health Program (PNNS), implemented in 2001, was aimed at...

Evolution of the Nile deep‐sea turbidite system during the Late Quaternary: influence of climate change on fan sedimentation

Abstract: This paper presents an overview of the evolution of the Nile deep-sea turbidite system during the last 200 kyr, over a series of glacial to interglacial cycles. Six individual deep-sea fans were identified from an extensive field data set. Each fan comprises a canyon, channel system and terminal lobes. Two of these fan systems were possibly active at the same time, at least during some periods. Large-scale slope failures destroyed channel segments and caused the formation of new submarine fan systems. These slope failures thus played an important role in the overall evolution of the turbidite system. During the last glacial maximum (ca 25 to 14·8 ka) the central and eastern parts of the Nile deep-sea turbidite system were relatively inactive. This inactivity corresponds to a lowstand in sea-level, and a period of arid climate and relatively low sediment discharge from the Nile fluvial system. Rapid accumulation of fluvial flood-derived deposits occurred across the shallower part of the submarine delta during sea-level rise between ca 14·8 and 5 ka. The most recent deep-sea channel–lobe system was very active during this period of rising sea-level, which is also associated with a wetter continental climate and increased sediment and water discharge from the Nile. Increased sediment deposition in shallower water areas led to occasional large-scale slope failure. The Nile deep-sea turbidite system was largely inactive after ca 5 ka. This widespread inactivity is due to retreat of the coastline away from the continental shelf break, and to a more arid continental climate and reduced discharge of sediment from the Nile. The Nile deep-sea turbidite system may be more active during periods of rising and high sea-level associated with wetter climates, than during lowstands, and may rapidly become largely inactive during highstands in sea-level coupled with arid periods. These acute responses to climate change have produced sedimentary/stratigraphic features that diverge from traditional sequence models in their nature and timing. This large-scale sedimentary system responded to monsoon-driven climate change and sea-level change in a system-wide and contemporaneous manner.

Prototype filter design for filter bank based multicarrier transmission

Abstract: This paper concentrates on an efficient prototype filter design in the context of filter bank based multicarrier (FBMC) transmission. An advantage of the chosen method, frequency sampling technique, is that near perfect reconstruction prototype filters can be expressed using a closed-form representation with only a few adjustable parameters. The performance of various designs are analyzed using the offset-QAM based FBMC system. Numerical results are provided to characterize different optimization criteria in terms of frequency selectivity of resulting prototype filters and total interference level of the filter bank structure. Furthermore, it is shown what kind of performance trade-offs can be obtained by adjusting those free parameters. In this sense, the presented results offer useful information to a system designer.

Peripatetic health-care workers as potential superspreaders

Abstract: Many nosocomial outbreaks exhibit “superspreading events” in which cross-transmission occurs via a single individual to a large number of patients. We investigated how heterogeneity in Health-Care Worker (HCW) behaviors, especially compliance to hand hygiene, may cause superspreading events. In particular, we compared the superspreading potential of peripatetic (noncohorted) HCWs with that of other HCWs. We developed an agent-based model for hand transmission of a pathogen in a hospital ward. Three HCW profiles were allowed: 2 assigned profiles, one with frequent contacts with a limited number of patients, another with fewer contacts but with more patients; and one peripatetic profile, with a single daily contact with all patients. We used data from the literature on common nosocomial pathogens (Staphylococcus aureus, Enterococci). The average number of patients colonized over 1 month increases with noncompliance to hand hygiene. Importantly, we show that this increase depends on the profile of noncompliant HCWs; for instance, it remains low for a single noncompliant assigned HCW but can be quite large for a single noncompliant peripatetic HCW. Outbreaks with this single fully noncompliant peripatetic HCW (representing only 4.5% of the staff) are similar to those predicted when all HCWs are noncompliant following 23% of patient contacts. Noncompliant peripatetic HCWs may play a disproportionate role in disseminating pathogens in a hospital ward. Their unique profile makes them potential superspreaders. This suggests that average compliance to hygiene may not be a good indicator of nosocomial risk in real life health care settings with several HCW profiles.

Suppression of HIV-1 replication by microRNA effectors.

Abstract: The rate of HIV-1 gene expression is a key step that determines the kinetics of virus spread and AIDS progression. Viral entry and gene expression were described to be the key determinants for cell permissiveness to HIV. Recent reports highlighted the involvement of miRNA in regulating HIV-1 replication post-transcriptionally. In this study we explored the role of cellular factors required for miRNA-mediated mRNA translational inhibition in regulating HIV-1 gene expression. Here we show that HIV-1 mRNAs associate and co-localize with components of the RNA Induced Silencing Complex (RISC), and we characterize some of the proteins required for miRNA-mediated silencing (miRNA effectors). RCK/p54, GW182, LSm-1 and XRN1 negatively regulate HIV-1 gene expression by preventing viral mRNA association with polysomes. Interestingly, knockdown of RCK/p54 or DGCR8 resulted in virus reactivation in PBMCs isolated from HIV infected patients treated with suppressive HAART.

Genomewide Association Study of a Rapid Progression Cohort Identifies New Susceptibility Alleles for AIDS (ANRS Genomewide Association Study 03)

Abstract: BACKGROUND Previous genomewide association studies (GWASs) of AIDS have targeted end points based on the control of viral load and disease nonprogression. The discovery of genetic factors that predispose individuals to rapid progression to AIDS should also reveal new insights into the molecular etiology of the pathology. METHODS We undertook a case-control GWAS of a unique cohort of 85 human immunodeficiency virus type 1 (HIV-1)-infected patients who experienced rapid disease progression, using Illumina HumanHap300 BeadChips. The case group was compared with a control group of 1352 individuals for the 291,119 autosomal single-nucleotide polymorphisms (SNPs) passing the quality control tests, using the false-discovery rate (FDR) statistical method for multitest correction. RESULTS Novel associations with rapid progression (FDR, < or = 25%) were identified for PRMT6 (P = 6.1 x 10(-7); odds ratio [OR], 0.24), SOX5 (P = 1.8 x 10(-6); OR, 0.45), RXRG (P = 3.9 x 10(-6); OR, 3.29), and TGFBRAP1 (P = 7 x 10(-6); OR, 0.34). The haplotype analysis identified exonic and promoter SNPs potentially important for PRMT6 and TGFBRAP1 function. CONCLUSIONS The statistical and biological relevance of these associations and their high ORs underscore the power of extreme phenotypes for GWASs, even with a modest sample size. These genetic results emphasize the role of the transforming growth factor beta pathway in the pathogenesis of HIV-1 disease. Finally, the wealth of information provided by this study should help unravel new diagnostic and therapeutic targets.

Prevalence of overweight in 6- to 15-year-old children in central/western France from 1996 to 2006: trends toward stabilization.

Abstract: The prevalence of overweight in children has markedly increased over the past few decades in France, as in all Western countries. We sought to describe the yearly prevalence of childhood overweight from 1996 to 2006 and to assess whether a shift in trends could be observed dating from the time the Nutrition and Health National Program (PNNS) was set up in France in 2001, in particular according to gender, age and family economic status. We used annual overweight prevalence of standardized 6- to 15-year-old populations (total=26 600) with weight and height measured at health examination centers in the central/western part of France between 1996 and 2006. Regression slopes of overweight prevalence were evaluated between 1996 and 2006, and specifically between 1996 and 2001, and 2001 and 2006. The annual prevalence and estimated slopes were compared in subgroups, taking into account gender, age and economic status of the family. The prevalence increased between 1996 (11.5%) and 1998 (14.8%) and was stable between 1998 and 2006 (15.2%). According to linear regression, the overall trend in prevalence of overweight children between 1996 and 2006 was stable (slope=0.19, P=0.08). Similarly, the prevalence of overweight increased between 1996 and 1998 in boys and girls, in 6–10 year olds, in 11–15 year olds and in non-disadvantaged children, and remained stable thereafter. The prevalence of overweight in the disadvantaged group increased between 1996 (12.8%) and 2001 (18.9%) (slope=1.16, P=0.004) and was stable between 2001 and 2006 (18.2%) (slope=0.09, P=0.78). The results of this study reveal a stable prevalence of overweight since 1998 in most groups studied, and since 2001 in the disadvantaged group.

Évaluation du travail et reconnaissance

Abstract: Cet article aborde le theme de l’evaluation a partir de l’analyse du travail proposee en psychodynamique du travail. L’analyse des situations de travail et de la maniere dont l’experience du travail determine l’etablissement du rapport au reel permet de developper une conception critique des fondements de l’evaluation. A partir de la reference a la dynamique de la reconnaissance du travail et de ses effets sur l’identite, les auteurs proposent plusieurs arguments en faveur de la centralite subjective du travail. Ils expliquent enfin en quoi cette these permet de remettre en cause les pratiques d’evaluation individualisee et quantitative du travail a partir de l’exemple de la dynamique de la reconnaissance.

The internal structure of rock glaciers and recently deglaciated slopes as revealed by geoelectrical tomography: insights on permafrost and recent glacial evolution in the Central and Western Alps (Italy–France)

Abstract: Ground ice of permafrost origin and sedimentary ice of glacial origin can coexist in locations where rock glaciers and glaciers interacted, as well as in glacigenic sediments abandoned by a retreating glacier and subsequently exposed again to atmospheric cooling. Some of these geomorphological settings in the Central (Foscagno rock glacier) and Western Alps (Marinet and Schiantala rock glaciers, Schiantala debris-covered glacier, Maledia glacier) were explored by means of geoelectrical tomographies. The aim was that of inferring the presence of ice and cryologically interpreting electrical stratigraphies in order to test whether or not the internal structure of these landforms can be used for the reconstruction of recent permafrost and glacier evolution. Geomorphological data assisted these reconstructions and available borehole stratigraphies were used to calibrate the resistivities. Along with the ice-debris mixture, massive ice has also been found as lenses both at the apex and the front of the studied rock glaciers. These lenses of sedimentary origin are thought to be transferred from a glacier snout to sectors of rock glacier and eventually embedded into the permafrost creep. The scarcity of frozen debris in the mid-upper part of the rock glaciers – as revealed by low resistivity values – can be due to the disruptive effect of the over-riding glacier over the permafrost. The near-surface sedimentary ice masses detected along the slopes of the studied glacial cirques are interpreted as or debris-covered terminations of the glaciers still visible upward, or as fragments of it detached by the main bodies. These ice masses are locally associated to medium–high resistive sediments, consistent with permafrost occurrence. This indicates that the non-glacial environment established during the deglaciation allowed the onset of frozen sediments formation. Overall, the results indicate that internal structure of rock glaciers and recent-deglaciated slopes can store the different climate-related episodes occurred in a specific area, such as those linked to the shifting between glacial to criotic condition and vice-versa.

Filter bank based multi-mode multiple access scheme for wireless uplink

Abstract: This paper investigates the potential of filter bank (FB) processing in the context of uplink multi-user access. First, a FB based scheme, conceptually similar to the single carrier frequency division multiple access (SC-FDMA) developed by 3GPP for uplink in the Long Term Evolution of UMTS, is analyzed. Specifically, a method for synthesizing spectrally well-localized uplink waveforms with low peak-to-average power ratio, using FB based multicarrier (FBMC) modulation in combination with FB spreading, is introduced. Secondly, the superior frequency selectivity of the FB approach, when combined with frequency sampling -designed subchannel/subband processing, is found to enable flexible and bandwidth efficient multi-mode uplink transmission with relaxed constraints on inter-user timing synchronization. The proposed concept allows different mobile terminals to operate in the reverse link simultaneously in multicarrier, SC-FDMA, or conventional single carrier mode according to attributes such as the required transmission power.

Non-linear vibrations of imperfect free-edge circular plates and shells

Abstract: Large-amplitude, geometrically non-linear vibrations of free-edge circular plates with geometric imperfections are addressed in this work. The dynamic analog of the von Karman equations for thin plates, with a stress-free initial deflection, is used to derive the imperfect plate equations of motion. An expansion onto the eigenmode basis of the perfect plate allows discretization of the equations of motion. The associated non-linear coupling coefficients for the imperfect plate with an arbitrary shape are analytically expressed as functions of the cubic coefficients of a perfect plate. The convergence of the numerical solutions are systematically addressed by comparisons with other models obtained for specific imperfections, showing that the method is accurate to handle shallow shells, which can be viewed as imperfect plate. Finally, comparisons with a real shell are shown, showing good agreement on eigenfrequencies and mode shapes. Frequency-response curves in the non-linear range are compared in a very peculiar regime displayed by the shell with a 1:1:2 internal resonance. An important improvement is obtained compared to a perfect spherical shell model, however some discrepancies subsist and are discussed.

Bimodal Behavior of the Heaviest Fragment Distribution in Projectile Fragmentation

Abstract: The charge distribution of the heaviest fragment detected in the decay of quasiprojectiles produced in intermediate energy heavy-ion collisions has been observed to be bimodal. This feature is expected as a generic signal of phase transition in nonextensive systems. In this Letter, we present new analyses of experimental data from Au on Au collisions at 60, 80, and 100 MeV/nucleon showing that bimodality is largely independent of the data selection procedure and of entrance channel effects. An estimate of the latent heat of the transition is extracted.

Pricing and Inference with Mixtures of Conditionally Normal Processes

Abstract: The main objective of this paper is to exploit important properties of the mixtures of normal distributions and of conditionally normal processes in order to propose flexible and tractable discrete-time option pricing models, based on the exponential-affine stochastic discount factor (SDF) modeling principle. These models deal simultaneously and coherently with the historical and risk-neutral worlds, they can be static or dynamic and, moreover, they can be parametric or semi-parametric. In the static setting our approach provide explicit historical and risk-neutral stock returns distributions and closed-form formulas for European option prices of any residual maturity. These pricing formulas turn out to be convex combinations of Black and Scholes formulas. The previous approach is extended to the dynamic case in several ways. First, by assuming that a Mixed Normal distribution is valid for the standardized error terms. Second, by considering mixtures of conditionally Gaussian processes and, third, by adopting a semi-parametric approach which estimates the distribution of standardized error terms by mixtures of normals based on a kernel method. Some numerical exercise shows the ability of our European option pricing models to replicate implied volatility smiles, volatility skews and volatility surfaces coherently with observations.