421 research outputs found

    Motorisation et localisation : quels effets sur le choix du modal ?

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    Motorisation et localisation sont, dans leur acception commune, deux variables liées, de même que le sont leurs effets sur le choix modal. Rares sont les méthodes permettant toutefois de tenir compte adéquatement de ces corrélations. C'est dans cette optique que Bonnel (2000) a développé une méthodologie permettant d'isoler les effets de chacune de ces variables. À ce jour, la méthode de décomposition des effets, développée par cet auteur a été appliquée au cas de Lyon. La présente recherche propose une transposition de la méthode au contexte de la grande région de Montréal. Cette expérimentation permet d'une part d'identifier et de mesurer les effets de la localisation et de la motorisation sur le choix modal dans le contexte bien particulier montréalais et, d'autre part, de comparer les résultats obtenus avec ceux présentés en ce qui concerne l'agglomération lyonnaise. Il est alors possible de discuter de l'applicabilité de la méthode à différents contextes urbains et de valider sa pertinence. Les données provenant des quatre plus récentes enquêtes Origine-Destination tenues à Montréal sont exploitées à cette fin. Ces expérimentations confirment que la méthode permet de dissocier les effets des variables explicatives et démontrent, à l'instar de Lyon, que l'évolution des localisations a joué un rôle plus important que la motorisation dans la régression de la part de marché des transports en commun à Montréal. Les perspectives de développement de la méthode semblent nombreuses, au travers notamment de la prise en compte de l'offre de transports en commun et de voirie, de la segmentation de la clientèle ou d'une désagrégation plus importante de l'espace.Choix modal ; comportement de déplacement ; enquêtes Origine-Destination ; enquête ménages ; agglomération ; Lyon ; Montréal

    Optical fiber sensors implementation for monitoring the early-age behavior of full-scale timber-concrete composite slabs

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    The study of the early-age behavior of Timber-Concrete Composite (TCC) structures is of great interest as it provides valuable information for manufacturing specification development, quality control, and optimization of the formwork design. In this study, the results of the continuous monitoring of the short-term behavior of TCC slabs using Brillouin Distributed Optical Fiber Sensors (DOFS) are reported. Two TCC slabs with 8.5 m of length were monitored. The composite elements are constituted of Cross-Laminated Timber (CLT) connected to a High-Performance Concrete (HPC) slab. During a monitoring period of about 30 days, the early-age temperature/strain variation in the fresh concrete and in the CLT slab was measured in great details by DOFS. From the presented results, the significant influence of the curing conditions on the early-age shrinkage was highlighted. It was also observed that creep and the daily hygrometric variations of environment affect considerably the composite action between the timber and the concrete. In addition, it was experimentally demonstrated that such mechanisms generate considerable structural changes in the composite elements even before their entry into service

    A library of H band stellar spectra for stellar population analysis purposes

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    A sample of 37 stars of luminosity classes I, III, V, including few SMR stars observed in the H band with a medium resolution (R=1500−2000) is presented. This sample of flux calibrated spectra is intended to widen existing stellar libraries. A new IR spectrograph, ISIS/IR, foreseen for CFHT has been used. Its main characteristics are briefly described. Stellar spectra obtained with this new spectrograph are compared to similar data obtained with the ESO NTT IRSPEC spectrograph. The behaviour of some prominent features is described and it is shown that the CO 1.60/SiI 1.60 line ratio is a good luminosity indicator for stellar types later than K0

    Wearable video monitoring of people with age Dementia : Video indexing at the service of helthcare

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    International audienceExploration of video surveillance material for healthcare becomes a reality in medical research. In this paper we propose a video monitoring system with wearable cameras for early diagnostics of Dementia. A video acquisition set-up is designed and the methods are developed for indexing the recorded video. The noisiness of audio-visual material and its particularity yield challenging problems for automatic indexing of this content

    Differential regulation of abundance and deadenylation of maternal transcripts during bovine oocyte maturation in vitro and in vivo

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    <p>Abstract</p> <p>Background</p> <p>In bovine maturing oocytes and cleavage stage embryos, gene expression is mostly controlled at the post-transcriptional level, through degradation and deadenylation/polyadenylation. We have investigated how post transcriptional control of maternal transcripts was affected during in vitro and in vivo maturation, as a model of differential developmental competence.</p> <p>Results</p> <p>Using real time PCR, we have analyzed variation of maternal transcripts, in terms of abundance and polyadenylation, during in vitro or in vivo oocyte maturation and in vitro embryo development. Four genes are characterized here for the first time in bovine: ring finger protein 18 (<it>RNF18</it>) and breast cancer anti-estrogen resistance 4 (<it>BCAR4</it>), whose oocyte preferential expression was not previously reported in any species, as well as Maternal embryonic leucine zipper kinase (<it>MELK</it>) and <it>STELLA</it>. We included three known oocyte marker genes (Maternal antigen that embryos require (<it>MATER</it>), Zygote arrest 1 (<it>ZAR1</it>), NACHT, leucine rich repeat and PYD containing 9 (<it>NALP9</it>)). In addition, we selected transcripts previously identified as differentially regulated during maturation, peroxiredoxin 1 and 2 (<it>PRDX1, PRDX2</it>), inhibitor of DNA binding 2 and 3 (<it>ID2</it>, <it>ID3</it>), cyclin B1 (<it>CCNB1</it>), cell division cycle 2 (<it>CDC2</it>), as well as Aurora A (<it>AURKA</it>). Most transcripts underwent a moderate degradation during maturation. But they displayed sharply contrasted deadenylation patterns that account for variations observed previously by DNA array and correlated with the presence of a putative cytoplasmic polyadenylation element in their 3' untranslated region. Similar variations in abundance and polyadenylation status were observed during in vitro maturation or in vivo maturation, except for <it>PRDX1</it>, that appears as a marker of in vivo maturation. Throughout in vitro development, oocyte restricted transcripts were progressively degraded until the morula stage, except for <it>MELK </it>; and the corresponding genes remained silent after major embryonic genome activation.</p> <p>Conclusion</p> <p>Altogether, our data emphasize the extent of post-transcriptional regulation during oocyte maturation. They do not evidence a general alteration of this phenomenon after in vitro maturation as compared to in vivo maturation, but indicate that some individual messenger RNA can be affected.</p

    Potential of Incorporation of Antimicrobial Plant Phenolics Into Polyolefin-Based Food Contact Materials to Produce Active Packaging by Melt-Blending: Proof of Concept With Isobutyl-4-Hydroxybenzoate

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    There is an increasing interest for active food packaging incorporated with natural antimicrobial agents rather than synthetic preservatives. However, most of plastics for direct contact with food are made of polyolefins, usually processed by extrusion, injection, or blow-molding methods while most of natural antimicrobial molecules are thermolabile compounds (e.g., essential oils). Therefore, addition of plant phenolics (with low volatility) to different polyolefins might be promising to design active controlled release packaging processed by usual plastic compounding and used for direct contact with food products. Therefore, up to 2% (wt/wt) of isobutyl-4-hydroxybenzoate (IBHB) was mixed with 3 polyolefins: EVA poly(ethylene-co-vinyl acetate), LLDPE (Linear Low Density Polyethylene), and PP (PolyPropylene) by melt-blending from 75 to 170°C and then pelletized in order to prepare heat-pressed films. IBHB was chosen as an antibacterial phenolic active model molecule against Staphylococcus aureus to challenge the entire processing. Antibacterial activity of films against S. aureus (procedure adapted from ISO 22196 standard) were 4, 6, and 1 decimal reductions in 24 h for EVA, LLDPE, and PP films, respectively, demonstrating the preservation of the antibacterial activity after melt processing. For food contact materials, the efficacy of antimicrobial packaging depends on the release of the antimicrobial molecules. Therefore, the three types of films were placed at 23°C in 95% (v/v) ethanol and the release rates of IBHB were monitored: 101 ± 1%, 32 ± 7%, and 72 ± 9% at apparent equilibrium for EVA, LLDPE, and PP films, respectively. The apparent diffusion coefficients of IBHB in EVA and PP films were 2.8 ± 0.3 × 10−12 and 4.0 ± 1.0 × 10−16 m2s−1. For LLDPE films, IBHB crystals were observed on the surface of films by SEM (Scanning Electron Microscopy): this blooming effect was due the partial incompatibility of IBHB in LLDPE and its fast diffusion out of the polymer matrix onto the film surface. In conclusion, none of these three materials was suitable for a relevant controlled release packaging targeting the preservation of fresh food, but a combination of two of them is promising by the design of a multilayer packaging: the release could result from permeation through an inner PE layer combined with an EVA one acting as a reservoir

    Reproductive Technologies and Genomic Selection in Cattle

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    The recent development of genomic selection induces dramatic changes in the way genetic selection schemes are to be conducted. This review describes the new context and corresponding needs for genomic based selection schemes and how reproductive technologies can be used to meet those needs. Information brought by reproductive physiology will provide new markers and new improved phenotypes that will increase the efficiency of selection schemes for reproductive traits. In this context, the value of the reproductive techniques including assisted embryo based reproductive technologies (Multiple Ovaluation Embryo Transfer and Ovum pick up associated to in vitro Fertilization) is also revisited. The interest of embryo typing is discussed. The recent results obtained with this emerging technology which are compatible with the use of the last generation of chips for genotype analysis may lead to very promising applications for the breeding industry. The combined use of several embryo based reproductive technologies will probably be more important in the near future to satisfy the needs of genomic selection for increasing the number of candidates and to preserve at the same time genetic variability

    Antiherpetic drugs: a potential way to prevent Alzheimer's disease?

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    BACKGROUND: Considering the growing body of evidence suggesting a potential implication of herpesviruses in the development of dementia, several authors have questioned a protective effect of antiherpetic drugs (AHDs) which may represent a new means of prevention, well tolerated and easily accessible. Subsequently, several epidemiological studies have shown a reduction in the risk of dementia in subjects treated with AHDs, but the biological plausibility of this association and the impact of potential methodological biases need to be discussed in more depth. METHODS: Using a French medico-administrative database, we assessed the association between the intake of systemic AHDs and the incidence of (i) dementia, (ii) Alzheimer's disease (AD), and (iii) vascular dementia in 68,291 subjects over 65 who were followed between 2009 and 2017. Regarding potential methodological biases, Cox models were adjusted for numerous potential confounding factors (including proxies of sociodemographic status, comorbidities, and use of healthcare) and sensitivity analyses were performed in an attempt to limit the risk of indication and reverse causality biases. RESULTS: 9.7% of subjects (n=6642) had at least one intake of systemic AHD, and 8883 incident cases of dementia were identified. Intake of at least one systemic AHD during follow-up was significantly associated with a decreased risk of AD (aHR 0.85 95% confidence interval [0.75-0.96], p=0.009) and, to a lesser extent with respect to p values, to both dementia from any cause and vascular dementia. The association with AD remained significant in sensitivity analyses. The number of subjects with a regular intake was low and prevented us from studying its association with dementia. CONCLUSIONS: Taking at least one systemic AHD during follow-up was significantly associated with a 15% reduced risk of developing AD, even after taking into account several potential methodological biases. Nevertheless, the low frequency of subjects with a regular intake questions the biological plausibility of this association and highlights the limits of epidemiological data to evaluate a potential protective effect of a regular treatment by systemic AHDs on the incidence of dementia

    Statement on bioinformatics and capturing the benefits of genome sequencing for society

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    The HUGO Committee on Ethics, Law and Society (CELS) undertook a Working Group exploration of the key ethical issues arising from genome sequencing in 2013. The Imagined Futures paper the group subsequently published proposed points to consider when applying genomic bioinformatics to data repositories used in genomic medicine and research ( http://www.hugo-international.org/Resources/Documents/CELS_Article-ImaginedFutures_2014.pdf ). Given the ever-increasing power to sequence the human genome rapidly and inexpensively-as well as trends toward "Big Data" and "Open Science"-we take this opportunity to update and refine the key findings of that paper
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