209 research outputs found

    Chronic Vestibular Hypofunction Is Associated with Impaired Sleep: Results from the DizzyReg Patient Registry

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    Temporary or permanent vestibular hypofunction has been hypothesized to affect circadian rhythm, sleep, and thermoregulation. Chronic or long-term vestibular disorders such as unilateral vestibular hypofunction may have an even greater negative impact on sleep quality than acute vestibular problems. This study examines self-reported sleep quality, as assessed by the Pittsburgh Sleep Quality Index (PSQI), and its association with vestibular symptom duration in a group of patients with vestibular disorders. We used data from the cross-sectional DizzyReg patient registry of the German Center for Vertigo and Balance Disorders outpatient clinic. Vestibular diagnoses were ascertained based on the International Classification of Vestibular Disorders. A total of 137 patients were included (60% female, mean age 55.4 years, standard deviation, SD, 16.7). The mean PSQI total score was 6.3 (SD = 3.2), with 51% reporting overall poor sleep quality. Patients who had vertigo for two years or longer reported significantly poorer global sleep quality (63% vs. 37%, p = 0.021) and significantly more difficulties with sleep latency (79% vs. 56%, p = 0.013) and sleep efficiency (56% vs. 34%, p = 0.022). The association of poor sleep quality with a longer duration of vertigo remained significant after multivariable adjustment. Further research should investigate the interaction of vestibular disorders, sleep, and their potential mechanisms

    La dynamique fait son cinéma : De l'apport de l'imagerie et des mesures de champs cinématiques pour l'analyse du comportement dynamique des matériaux

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    National audienceDepuis de nombreuses décennies, l'imagerie rapide a permis d'observer des phénomÚnes se produisant sur des échelles de temps trÚs petites (de l'ordre de la milliseconde voire de la microseconde). Avec l'avÚnement plus récent des caméras numériques, de nouvelles applications sont possibles (p.ex. la tomographie rapide). L'utilisation quantitative d'images est également possible, notamment grùce aux techniques de corrélation et de stéréocorrélation d'images. Différentes applications seront présentées afin d'illustrer les apports pour l'analyse du comportement mécanique des matériaux sous sollicitations dynamiques

    Mesure de la Largeur Spectrale d'un Laser Cohérent par Injection Optique

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    session VII « Cristaux photoniques en optique planaire I, fonctions spéciales » [704]National audienceNous proposons une nouvelle méthode de mesure de faibles largeurs spectrales pour des lasers métrologiques. La mesure comparative repose sur une injection optique. Nous présentons la mesure expérimentale en bande C d'un laser de pleine largeur spectrale à mi-hauteur 50 kHz, en comparaison à une référence de largeur 125 kHz. Un modÚle théorique reposant sur la fonction d'Airy généralisée est aussi présenté, tenant compte des outils d'analyse expérimentaux utilisés

    Identification of viscoplastic parameters and characterization of LĂŒders behaviour using digital image correlation and the virtual fields method

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    In this study, tensile loading experiments are performed on notched steel bars at an average applied strain rate of 1s-1. Displacement fields are measured across the specimen by coupling digital image correlation (DIC) with imaging using high speed CCD cameras (4796 fps). Results from the experiments indicate the presence of local strain rates ranging from 0.1 to 10s-1 in the notched specimens. The heterogeneity of the strain rate fields provides suitable conditions for determining simultaneously all the elasto-visco-plastic constitutive parameters governing the material behavior. For that, the whole stress fields are reconstructed in the specimen using the full-field deformation measurements. This reconstruction is repeated with different constitutive parameters until the average stress in the specimen matches the one measured with the load cell response. Perzyna’s model is firstly considered for the reconstruction of stresses but it is shown to be unsuited for providing the drop in the average stress that is systematically detected at the onset of plasticity by the load cell. This drop is attributed to the sudden occurrence of plasticity in the material due to LĂŒders effect. A modified model for elasto-visco-plasticity taking account of LĂŒders behavior in the material is considered afterwards. It yields a better agreement between the reconstructed stresses and the load cell response, and a more accurate identification of the parameters driving the visco-plastic model. Eventually, it is shown how to use DIC measurements for replacing the load cell measurements when the transient effects in the test reach the resonance frequency of the load cel

    Spectral and Time Phenomena in Optical Injection Using Distributed Feedback Semiconductor or Fiber Lasers

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    http://www.iop.vast.ac.vn/activities/5-8April/Proceedings_IWPA2004/proceeding_IWPA_2004.htmlInternational audienceOptical injection is compared for distributed feedback semiconductor and fibre lasers whose wavelength is around 1550 nm. A spectral description of an injected semiconductor laser is presented for usual injected power (> 30 dBm), by mapping out several phenomena, such as bistable areas, undamped relaxation and chaos synchronization. For weak injection levels (< 30 dBm), the slave acts as a highquality amplifier of spectrally narrow signals. In this case, the slave frequency is pulled by the master one. Theory of weak injection is demonstrated using a generalized Airy's function method. We also present the temporal response of a fibre laser output power for static injection, and observe original dynamics linked to relaxation processes. A new method using optical injection is proposed to measure narrow linewidth or spontaneous emission rate

    Adaptive niche-based sampling to improve ability to find rare and elusive species: Simulations and field tests

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    This is the peer reviewed version of the following article: Chiffard, Marciau, Yoccoz, Mouillot, Duchateau, Nadeau, Fontanilles, Besnard. Adaptive niche-based sampling to improve ability to find rare and elusive species: Simulations and field tests. Methods in Ecology and Evolution. 2020;11(8):899-909, which has been published in final form at https://doi.org/10.1111/2041-210X.13399. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. Sampling efficiency is crucial to overcome the data crisis in biodiversity and to understand what drives the distribution of rare species.</li Adaptive niche‐based sampling (ANBS) is an iterative sampling strategy that relies on the predictions of species distribution models (SDMs). By predicting highly suitable areas to guide prospection, ANBS could improve the efficiency of sampling effort in terms of finding new locations for rare species. Its iterative quality could potentially mitigate the effect of small and initially biased samples on SDMs. In this study, we compared ANBS with random sampling by assessing the gain in terms of new locations found per unit of effort. The comparison was based on both simulations and two field surveys of mountain birds. We found an increasing probability of contacting the species through iterations if the focal species showed specialization in the environmental gradients used for modelling. We also identified a gain when using pseudo‐absences during first iterations, and a general tendency of ANBS to increase the omission rate in the spatial prediction of the species' niche or habitat. Overall, ANBS is an effective and flexible strategy that can contribute to a better understanding of distribution drivers in rare species. </ol

    Patrimoines de la Seconde Guerre mondiale en Normandie

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    Ce projet collectif de recherche lancĂ© en 2015 vise Ă  inventorier dans les dĂ©partements du Calvados, de la Manche et de l’Orne tous les Ă©lĂ©ments du dernier conflit qui sont conservĂ©s, disparus ou enfouis, et Ă  en restituer la cohĂ©rence historique. Il vise particuliĂšrement Ă  Ă©tudier les diffĂ©rents Ă©lĂ©ments dans l’histoire du conflit et leur place dans les dispositifs militaires. Il porte donc aussi bien sur les vestiges liĂ©s Ă  l’Occupation que sur les vestiges alliĂ©s ou les traces et amĂ©nageme..

    Vestiges de la Seconde Guerre mondiale en Basse-Normandie

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    Ce programme collectif de recherche vise Ă  inventorier de maniĂšre exhaustive les Ă©lĂ©ments conservĂ©s, disparus ou enfouis, formant des ensembles cohĂ©rents, sans se limiter aux seules Ă©lĂ©vations, et Ă  apprĂ©hender les diffĂ©rents Ă©lĂ©ments dans l’histoire du conflit et leur place dans le dispositif dĂ©fensif. Il s’appuie Ă  la fois sur des Ă©tudes documentaires, des recherches de terrain ainsi que sur une base de donnĂ©es couplĂ©e Ă  un SIG. Ce projet rĂ©pond Ă  un besoin urgent de gestion de ce patrimoin..

    Vestiges de la Seconde Guerre mondiale en Basse-Normandie

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    Pour rappel, ce programme collectif de recherche vise Ă  inventorier de maniĂšre exhaustive les Ă©lĂ©ments conservĂ©s, disparus ou enfouis, formant des ensembles cohĂ©rents, sans se limiter aux seules Ă©lĂ©vations, et Ă  apprĂ©hender les diffĂ©rents Ă©lĂ©ments dans l’histoire du conflit et leur place dans le dispositif dĂ©fensif. Il s’appuie Ă  la fois sur des Ă©tudes documentaires, des recherches de terrain ainsi qu’une base de donnĂ©es couplĂ©e Ă  un SIG. Ce projet rĂ©pond Ă  un besoin urgent de gestion de ce p..

    Apports conjoints de l’ergonome et de l’ergothĂ©rapeute pour la conception d’aides techniques

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    L’objectif de cet article est de dĂ©montrer l’intĂ©rĂȘt d’une conception centrĂ©e sur les restrictions physiques et cognitives des utilisateurs d’aides techniques. Également, la plus-value d’une recherche effectuĂ©e par un binĂŽme de recherche ergonome-ergothĂ©rapeute sera exposĂ©e. À partir de situations rĂ©ellement vĂ©cues dans le cadre de notre Ă©tude, les bĂ©nĂ©fices de cette dĂ©marche seront exposĂ©s ainsi que la nĂ©cessitĂ© d’adaptation que celle-ci impose par rapport Ă  un mode de conception « classique ». En effet, donner de la voix aux personnes en situation de handicap Ă  la fois sur les Ă©lĂ©ments constitutifs de l’interface et sur les directions que doit prendre le dĂ©veloppement nĂ©cessite de s’adapter Ă  leur rythme, Ă  leur environnement et Ă  leur grand niveau de fatigabilitĂ©.The objective of this article is to demonstrate the potential of design focused on the physical and cognitive restrictions of those who use technical aids. The advantages of research conducted by an ergonomist and an occupational therapist will be described. Using real-life situations as a starting point, we outline the benefits of this approach, as well as the need for adaptation that it imposes compared to a "classic" design mode. Indeed, giving voice to people with disabilities on both the elements of the interface but also on the directions that must take development, requires that we adjust to their rhythms, their environments and their great level of fatigability.El objetivo del articule es de demonstrar los interĂ©s de un concepciĂłn centrada en la restricciones fĂ­sicas et cognitivas de los utilizadores de los ayudas tĂ©cnicas. Igualmente, el valor agregado de una bĂșsqueda efectuada por un binomio de investigaciĂłn “ergnono-ergoterapeuta” serĂĄ presentado. A partir de situaciones realmente vividas en el cuadro de nuestro estudio, los beneficios de ese enfoque serĂĄn esposados tambiĂ©n asĂ­ como la necesidad de adaptaciĂłn que ella impone en comparaciĂłn a une modo de concepciĂłn mĂĄs “clĂĄsico”. En efecto, dar de la voz a las personas en situaciĂłn de discapacidad Ă  la vez sobre les elementos constitutivos de la interfaz pero tambiĂ©n sobre la direcciones que debe tomar el desarrollo, necesidad de adaptarse a su ritmo, al medio ambiente et al gran nivel de cansancio
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