947 resultados para Preferential hyperacuity perimetry


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Dynamic exercise evokes sustained cardiovascular responses, which are characterized by arterial pressure and heart rate increases. Although it is well accepted that there is central nervous system mediation of cardiovascular adjustments during exercise, information on the role of neural pathways and signaling mechanisms is limited. It has been reported that glutamate, by acting on NMDA receptors, evokes the release of nitric oxide through activation of neuronal nitric oxide synthase (nNOS) in the brain. In the present study, we tested the hypothesis that NMDA receptors and nNOS are involved in cardiovascular responses evoked by an acute bout of exercise on a rodent treadmill. Moreover, we investigated possible central sites mediating control of responses to exercise through the NMDA receptor-nitric oxide pathway. Intraperitoneal administration of the selective NMDA glutamate receptor antagonist dizocilpine maleate (MK-801) reduced both the arterial pressure and heart rate increase evoked by dynamic exercise. Intraperitoneal treatment with the preferential nNOS inhibitor 7-nitroindazole reduced exercise-evoked tachycardiac response without affecting the pressor response. Moreover, treadmill running increased NO formation in the medial prefrontal cortex (MPFC), bed nucleus of the stria teminalis (BNST) and periaqueductal gray (PAG), and this effect was inhibited by systemic pretreatment with MK-801. Our findings demonstrate that NMDA receptors and nNOS mediate the tachycardiac response to dynamic exercise, possibly through an NMDA receptor-NO signaling mechanism. However, NMDA receptors, but not nNOS, mediate the exercise-evoked pressor response. The present results also provide evidence that MPFC, BNST and PAG may modulate physiological adjustments during dynamic exercise through NMDA receptor-NO signaling. © 2013 Elsevier B.V.

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LaNiO3 thin films were deposited on SrLaAlO4 (1 0 0) and SrLaAlO4 (0 0 1) single crystal substrates by a chemical solution deposition method and heat-treated in oxygen atmosphere at 700° C in tube oven. Structural, morphological, and electrical properties of the LaNiO 3 thin films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), and electrical resistivity as temperature function (Hall measurements). The X-ray diffraction data indicated good crystallinity and a structural preferential orientation. The LaNiO3 thin films have a very flat surface and no droplet was found on their surfaces. Samples of LaNiO3 grown onto (1 0 0) and (0 0 1) oriented SrLaAlO4 single crystal substrates reveled average grain size by AFM approximately 15-30 nm and 20-35 nm, respectively. Transport characteristics observed were clearly dependent upon the substrate orientation which exhibited a metal-to-insulator transition. The underlying mechanism is a result of competition between the mobility edge and the Fermi energy through the occupation of electron states which in turn is controlled by the disorder level induced by different growth surfaces. © 2013 Elsevier Ltd and Techna Group S.r.l.

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Pós-graduação em Agronomia (Agricultura) - FCA

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Pesquisa e Desenvolvimento (Biotecnologia Médica) - FMB

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Includes bibliography

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Incluye Bibliografía

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Pós-graduação em Educação - FFC

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Includes bibliography

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Includes bibliography

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Includes bibliography

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Access to Latin American and Caribbean Exports in the United States market, 2001-2002 is the seventh annual report released by the ECLAC Washington Office, updating information contained in previous reports. Its aim is to compile and make available information on trade inhibiting measures that Latin American and Caribbean exports encounter in the United States market. This report needs to be placed in the context of a trade relationship between the United States and Latin America and the Caribbean, which has grown strongly over the years to the benefit of both economies. Moreover, it must be viewed against the background of the commitment to achieve the Free Trade Area of the Americas (FTAA), through which barriers to trade and investment will be progressively eliminated. In this regard, it is hoped that this report will further contribute to transparency and the elimination of obstacles to the free flow of trade in the Americas. The classification of trade inhibiting measures follows the definition used in the U.S. Trade Representatives (USTR) yearly publication National Trade Estimate Report on Foreign Trade Barriers. Based on this structure, the report focuses on the three areas of greatest relevance for Latin America and the Caribbean: Imports Policies (e.g., tariffs and other import charges, quantitative restrictions, import licensing, customs barriers). Standards, testing, labeling and certification (e.g., unnecessarily restrictive application of phytosanitary standards). Export subsidies (e.g., export financing on preferential terms and agricultural export subsidies that displace other foreign exports in third country markets).