An integrated circuit switch

Multi-chip integrated circuit switch consists of a GaAs photon-emitting diode in close proximity with S1 phototransistor. A high current gain is obtained when the transistor has a high forward common-emitter current gain

Photon-coupled isolation switch Quarterly report, 1 Jan. - 31 Mar. 1967

Design, development, and testing of new integrated circuit switch devic

Photon-coupled isolation switch Quarterly report, 1 Oct. - 31 Dec. 1966

Integrated circuit photon coupled isolation switc

Photon-coupled isolation switch Quarterly report, 1 Jul. - 30 Sep. 1966

Integrated circuit isolation switch using photon couplin

Photon-coupled isolation switch Quarterly report, 1 Jul. - 30 Sep. 1967

Development of gallium arsenide laser diode with silicon phototransistor for optical isolation switc

Photon-coupled isolation switch Final report, 1 Jan. 1966 - 31 Mar. 1968

Electro-optic techniques for developing miniature photon-coupled integrated circui

Hippocampus-dependent emergence of spatial sequence coding in retrosplenial cortex.

Retrosplenial cortex (RSC) is involved in visuospatial integration and spatial learning, and RSC neurons exhibit discrete, place cell-like sequential activity that resembles the population code of space in hippocampus. To investigate the origins and population dynamics of this activity, we combined longitudinal cellular calcium imaging of dysgranular RSC neurons in mice with excitotoxic hippocampal lesions. We tracked the emergence and stability of RSC spatial activity over consecutive imaging sessions. Overall, spatial activity in RSC was experience-dependent, emerging gradually over time, but, as seen in the hippocampus, the spatial code changed dynamically across days. Bilateral but not unilateral hippocampal lesions impeded the development of spatial activity in RSC. Thus, the emergence of spatial activity in RSC, a major recipient of hippocampal information, depends critically on an intact hippocampus; the indirect connections between the dysgranular RSC and the hippocampus further indicate that hippocampus may exert such influences polysynaptically within neocortex

Colossal magnetoresistance in an ultra-clean weakly interacting 2D Fermi liquid

We report the observation of a new phenomenon of colossal magnetoresistance in a 40 nm wide GaAs quantum well in the presence of an external magnetic field applied parallel to the high-mobility 2D electron layer. In a strong magnetic field, the magnetoresistance is observed to increase by a factor of ~300 from 0 to 45T without the system undergoing any metal-insulator transition. We discuss how this colossal magnetoresistance effect cannot be attributed to the spin degree-of-freedom or localization physics, but most likely emanates from strong magneto-orbital coupling between the two-dimensional electron gas and the magnetic field. Our observation is consistent with a field-induced 2D-to-3D transition in the confined electronic system

Dynamique d'acteurs ( agriculteurs et institutions) et innovation agro-écologique pour la gestion des risques environnementaux en Guadeloupe

Dans le contexte de crise économique et environnementale qui touche la filière banane à la Guadeloupe, l'objectif de cette contribution est d'engager une réflexion sur l'organisation d'acteurs à l'origine des innovations agro-écologiques. Nous interrogeons les dynamiques d'acteurs face aux crises et perturbations qui touchent l'agriculture antillaise, par le biais de l'organisation qu'ils mettent en place pour accompagner le changement. Des entretiens menés d'une part auprès d'un groupe de planteurs de bananes, d'autre part auprès des institutions en charge de la question environnementale sur l'île, ont permis de faire émerger trois principales conclusions sur la nature des innovations mises en oeuvre face aux crises environnementale et économique, leur échelle d'application et les forces motrices qui les sous-tendent : du point de vue technique, la mise en oeuvre de nouvelles pratiques indépendamment des échanges entre agriculteurs ; du point de vue stratégique, des changements d'orientation productive en liaison avec une forte dynamique d'échanges ; au niveau des institutions, de nouveaux lieux de dialogue. D'une manière générale, il apparaît qu'il y a un décalage dans la dynamique de concertation selon les niveaux d'organisation (agriculteurs vs institutions) et le lien entre ces deux niveaux d'organisation semble peu existant. / The aim of our research is to urge a reflexion on the agro-ecological innovations to manage the environmental risks. We analyse the organization that the stakeholders (farmers and institutions) set up facing the crises and disturbances which touch the agriculture of French West Indies. To do this, we enquired a group of farmers of banana production in Guadeloupe, and also the agricultural and environmental institutions of this island. This made it possible to identify three principal conclusions on the nature of the innovations, their scale of application and the driving forces which underlie them: from a technical point of view, new practices are implemented independently of the exchanges between farmers; from a strategic point of view, changes of production are made, depending on exchanges dynamic; on the level of the institutions, new places of dialogue are created. In conclusion, there is a shift in the dynamics of dialogue according to the levels of organization (farmers versus institutions) and the bond between these two levels of organization seems to be very thin.FILIERE;BANANE;INNOVATION;AGRICULTEUR;INSTITUTION;GUADELOUPE;RESEAU DE DIALOGUE ENTRE AGRICULTEURS;INNOVATION AGRO-ECOLOGIQUE