5,439 research outputs found

    Existence of global strong solutions in critical spaces for barotropic viscous fluids

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    This paper is dedicated to the study of viscous compressible barotropic fluids in dimension N2N\geq2. We address the question of the global existence of strong solutions for initial data close from a constant state having critical Besov regularity. In a first time, this article show the recent results of \cite{CD} and \cite{CMZ} with a new proof. Our result relies on a new a priori estimate for the velocity, where we introduce a new structure to \textit{kill} the coupling between the density and the velocity as in \cite{H2}. We study so a new variable that we call effective velocity. In a second time we improve the results of \cite{CD} and \cite{CMZ} by adding some regularity on the initial data in particular ρ0\rho_{0} is in H1H^{1}. In this case we obtain global strong solutions for a class of large initial data on the density and the velocity which in particular improve the results of D. Hoff in \cite{5H4}. We conclude by generalizing these results for general viscosity coefficients

    Effective lagrangian for a mass dimension one fermionic field in curved spacetime

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    In this work we use momentum-space techniques to evaluate the propagator G(x,x)G(x,x^{\prime}) for a spin 1/21/2 mass dimension one spinor field on a curved Friedmann-Robertson-Walker spacetime. As a consequence, we built the one-loop correction to the effective lagrangian in the coincidence limit. Going further we compute the effective lagrangian in the finite temperature regime. We arrive at interesting cosmological consequences, as time-dependent cosmological `constant', fully explaining the functional form of previous cosmological models.Comment: 9 pages, 0 figure

    On the bilinear covariants associated to mass dimension one spinors

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    In this paper we approach the issue of Clifford algebra basis deformation, allowing for bilinear covariants associated to Elko spinors which satisfy the Fierz-Pauli-Kofink identities. We present a complete analysis of covariance, taking into account the involved dual structure associated to Elko. Moreover, the possible generalizations to the recently presented new dual structure are performed.Comment: 9 pages, 0 figure

    Proton endor study of the photoexcited triplet state PT in Rps. sphaeroides R-26 photosynthetic reaction centres

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    The photoexcited triplet state PT of Rhodopseudomonas sphaeroides R-26 has been investigated by ENDOR measurements performed on frozen photosynthetic reaction centre solutions. For the first time hyperfine data could be obtained for PT. These data indicate a delocalisation of the triplet state over two bacteriochlorophyll a molecules

    On the Spinor Representation

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    A systematic study of the spinor representation by means of the fermionic physical space is accomplished and implemented. The spinor representation space is shown to be constrained by the Fierz-Pauli-Kofink identities among the spinor bilinear covariants. A robust geometric and topological structure can be manifested from the spinor space, wherein, for instance, the first and second homotopy groups play prominent roles on the underlying physical properties, associated to the fermionic fields.Comment: 16 page

    Monitoramento do ciclo de videiras pelo Índice de Vegetação por Diferença Normalizada obtido de imagens Landsat 8 no município de Veranópolis-RS, Brasil.

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    O objetivo deste trabalho foi monitorar o ciclo de videiras (Vitis vinifera) em diferentes sistemas de condução na Serra Gaúcha-RS por meio do Índice de Vegetação por Diferença Normalizada (NDVI) obtido de imagens Landsat8/OLI

    THE RESOURCE NEXUS Preface and introduction to the Routledge Handbook

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    Demand for natural resources has grown rapidly for decades, and is expected to continue growing. These trends lead to repercussions, risks, and threats for humans and ecosystems at different scales. The challenges of sustainable resource management and governance are on numerous agendas, ranging from the G7 and G20 summits to UNEP’s International Resource Panel, World Economic Forum, SDG implementation, and a growing community of international scholars. Research highlights the importance of accounting for the interdependencies of resource use and sustainability goals such as eliminating hunger, mitigating climate change, and expanding energy access. There is a need to understand interdependencies and the feasibility of more integrated approaches. Debate is often framed in terms of a “nexus” between water, energy, and food (sometimes including other resources). The main aim of this handbook is to come to grips with what the nexus is about, provide a reference textbook with an overview, and a survey on emerging and cutting-edge research, and application of the concept. This handbook is edited by five dedicated scholars, drawing on different schools of thought from different continents. Assembling a wide group of more than 50 authors across a host of disciplines and interdisciplinary fields, this volume rests on a thorough review of relevant literature and, in emerging with a distinct and original perspective, it conceptualizes the resource nexus as a heuristic for understanding critical interlinkages between uses of different natural resources for systems of provision such as water, energy, and food. The editors organized a symposium which took place in London in March 2015, debating various aspects of the resource nexus and refining the concept and defining the structure of the handbook. All chapters have been reviewed several times
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