Spinor stochastic resonance

International audienceWe report on noise-induced spin ordering in a collective quasiparticle system: spinor stochastic resonance. Synergetic interplay of a polarization-modulated signal and a polarization noise allows us to switch coherently between the two metastable states of a microcavity-polariton spin bistable system. Spinor stochastic resonance is demonstrated in a zero-dimensional GaAs based microcavity. The resonance behaviors of both the spin amplification and the signal-to-noise ratio are experimentally evidenced as a function of the noise strength for different amplitude modulations. They are theoretically reproduced using a spinor Gross-Pitaevskii equation driven by a randomly polarized laser field

Effect of a noisy driving field on a bistable polariton system

International audienceWe report on the effect of noise on the characteristics of the bistable polariton emission system. The present experiment provides a time-resolved access to the polariton emission intensity. We evidence the noise-induced transitions between the two stable states of the bistable polaritons. It is shown that the external noise specifications, intensity and correlation time, can efficiently modify the polariton Kramers time and residence time. We find that there is a threshold noise strength that provokes the collapse of the hysteresis loop. The experimental results are reproduced by numerical simulations using Gross-Pitaevskii equation driven by a stochastic excitation

Notch1 and Jagged1 are expressed after CNS demyelination, but are not a major rate-determining factor during remyelination

The reasons for the eventual failure of repair mechanisms in multiple sclerosis are unknown. The presence of precursor and immature oligodendrocytes in some non-repairing lesions suggests a mechanism in which these cells either receive insufficient differentiation signals or are exposed to differentiation inhibitors. Jagged signalling via Notch receptors on oligodendrocyte precursor cells (OPCs) inhibits their differentiation during development and the finding that both notch and jagged are expressed in multiple sclerosis lesions has fostered the view that this signalling pathway may explain remyelination failure. In this study, we show that Notch1 is expressed on adult OPCs and that there are multiple cellular sources of its ligand Jagged1 in a rodent model of remyelination. However, despite their expression, the lesions undergo complete remyelination. To establish whether Notch-jagged signalling regulates the rate of remyelination we compared their expression profiles in young animals with those in older animals, where remyelination occurs more slowly, but could find no correlation between expression and remyelination rate. Finally we found that OPC-targeted Notch1 ablation in cuprizone-treated Plp-creER Notch1lox/lox transgenic mice yielded no significant differences in remyelination parameters between knock-out and control mice. Thus, in contrast to developmental myelination, adult expression of Notch1 and Jagged1 neither prevents nor plays a major rate-determining role in remyelination. More generally, the re-expression of developmentally expressed genes following injury in the adult does not per se imply similar functio

Multi-method approach to compare the socio-demographic typology of residents and clusters of electricity load curves in a Swiss sustainable neighbourhood

A sustainable neighbourhood was built Switzerland by one of the leaders in this field. Half of the 400 apartments have been equipped with smart meters delivering big data on energy consumption (electricity, water, heating…). The company would like to know if it is possible to link socio-demographic typology of residents with energy consumption patterns. To answer this question we present in this article a multi-method approach combining qualitative analysis, frequently used in marketing (multiple correspondence analyses), and quantitative analysis from applied statistics to answer this question. First, we have conducted a survey among the residents of the sustainable neighbourhood to gather socio-demographic data, and then we have proposed a marketing typology of residents. In parallel, we have analysed load curves with statistical models (clustering factors, hermano beta models, coincidence factors, som, expert practice) to see if there are patterns of energy consumption and to determine groups of similar load curves. Then we have compared the discrepancies in the composition of the groups between both methods. This study is based on a single case study generating a new research hypothesis: the typology of residents based on socio-demographic data can be linked to energy consumption pattern of a household

Economic interest of heating and hot water prediction system for residential district

This work presents a data-intensive solution to predict heating and hot water consumption. The ability to predict locally those flexible sources considering meteorological uncertainty can play a key role in the management of microgrid. A microgrid is a building block of future smart grid, it can be defined as a network of low voltage power generating units, storage devices and loads. The main novelties of our approach is to provide an easy implemented and flexible solution which used supervised learning techniques. This paper presents an industrial methodology to predict heating and hot water consumption using time series analyzes and tree ensemble algorithm. Considering the winter season 2012-2013 for the training, the heating and hotwater predictions is correctly estimated 90% +/- 1.2 for the winter season 2013-2014. The results are based on the data collected in a building in Chamoson (Switzerland) and simulations. The aim is to provide to the virtual power plant the possibility to pilot an part of energy consumption. The input data for the pilot is the economic parameter. Considering the economic input data for the energy management, a new heasting and hot water consumption is provided for one week

Outil de prédiction solaire basé sur un calcul d'erreur météorologique

Le développement des énergies renouvelables passe par une meilleure anticipation de la variabilité de leurs productions. Un des freins aux développements de l’éolien et du photovoltaïque résident dans leurs variabilités de production liées aux conditions climatiques. Ainsi, la capacité de prévoir ces sources de production variables est essentielle pour le maintien d’un réseau électrique sécurisé et pour piloter des bâtiments en fonction de la prédiction de ces productions décentralisées. Ce travail présente une solution industriel d’analyse de données afin de prévoir l'énergie Photovoltaïque (PV) à partir de données réelles de production et météorologiques. Les données utilisées proviennent de la station photovoltaïque du quartier intelligent situé au techno-Pôle de Sierre et des données de production des différentes stations du distributeur d’énergie ESR pour la ville de Sion en Suisse. Ici sont présentés les résultats pour une station photovoltaïque parmi l’ensemble du parc de l’ESR. Notre approche combine des algorithmes de classification (Arbre de décision, Réseau de Neurones) pour prédire le PV d’une station considérant les conditions météorologiques et une régression non-linéaire pour prédire les erreurs de prédiction météorologique. Le système d’information permet aujourd’hui de récupérer les données météorologiques réelles et prédites avec un pas de temps d’une heure, la production produite à l’heure et de les stocker dans une base Influx DB. Par l’intermédiaire d’un service Web, une connexion est réalisée avec le logiciel d’analyse de données Knime pour traiter et calculer la prédiction et les marges d’erreur pour le jour suivant par heure. Une page web a été créée pour la personne responsable de la prédiction à l’ESR avec une connexion possible avec leur logiciel de prédiction existant Epredict pour y intégrer les données. Le système d’information créé est prêt pour intégrer les différentes énergies renouvelables décentralisées (photovoltaïque, barrages, éoliens).Ce projet nommé ELF4U a été financé par la fondation The Ark Energy

Noise-Induced Polariton Transitions in Optical Bistability

International audienc

Polychromatic selective lasing of confined polaritons

International audienceExciton-polaritons result from the strong coupling between an excitonic and a photonic mode and due to the easy manipulation of their density and spin they have been often proposed for the realization of all-optical devices. We hereby present a new relaxation mechanism for confined polaritons and its application in an innovative device in which the pump beam can be selectively channeled into several polariton lasers at different wavelengths

Motoneuron expression profiling identifies an association between an axonal splice variant of HDGF-related protein 3 and peripheral myelination

Disorders that disrupt myelin formation during development or in adulthood, such as multiple sclerosis and peripheral neuropathies, lead to severe pathologies, illustrating myelin's crucial role in normal neural functioning. However, although our understanding of glial biology is increasing, the signals that emanate from axons and regulate myelination remain largely unknown. To identify the core components of the myelination process, here we adopted a microarray analysis approach combined with laser-capture microdissection of spinal motoneurons during the myelinogenic phase of development. We identified neuronal genes whose expression was enriched during myelination and further investigated hepatoma-derived growth factor-related protein 3 (HRP3 or HDGFRP3). HRP3 was strongly expressed in the white matter fiber tracts of the peripheral (PNS) and central (CNS) nervous systems during myelination and remyelination in a cuprizone-induced demyelination model. The dynamic localization of HPR3 between axons and nuclei during myelination was consistent with its axonal localization during neuritogenesis. To study this phenomenon, we identified two splice variants encoded by theHRP3gene: the canonical isoform HRP3-I and a newly recognized isoform, HRP3-II. HRP3-I remained solely in the nucleus, whereas HRP3-II displayed distinct axonal localization both before and during myelination. Interestingly, HRP3-II remained in the nuclei of unmyelinated neurons and glial cells, suggesting the existence of a molecular machinery that transfers it to and retains it in the axons of neurons fated for myelination. Overexpression of HRP3-II, but not of HRP3-I, increased Schwann cell numbers and myelination in PNS neuron-glia co-cultures. However, HRP3-II overexpression in CNS co-cultures did not alter myelination.Christopher and Dana Reeve Foundation Roche Foundation Swiss National Science Foundation (SNSF) American Heart Association Paul G. Allen Frontiers Group Grant Leona M. and Harry B. Helmsley Charitable Trust Grant Grace Foundation JPB Foundation Robert and Mary Jane Engman Foundation Ray and Dagmar Dolby Family Fund Crick-Jacob Center for Theoretical and Computational Biology Neurosurgery Neuroscience Consortium Fellowshi