54 research outputs found

    Particle Production near an AdS Crunch

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    We numerically study the dual field theory evolution of five-dimensional asymptotically anti-de Sitter solutions of supergravity that develop cosmological singularities. The dual theory is an unstable deformation of the N = 4 gauge theory on R ×\times S3, and the big crunch singularity in the bulk occurs when a boundary scalar field runs to infinity. Consistent quantum evolution requires one imposes boundary conditions at infinity. Modeling these by a steep regularization of the scalar potential, we find that when an initially nearly homogeneous wavepacket rolls down the potential, most of the potential energy of the initial configuration is converted into gradient energy during the first oscillation of the field. This indicates there is no transition from a big crunch to a big bang in the bulk for dual boundary conditions of this kind.Comment: 20 pages, 6 figure

    Auroral Processes at the Giant Planets: Energy Deposition, Emission Mechanisms, Morphology and Spectra

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    The contribution of action research in the construction of scientific knowledge in Brazilian Production Engineering

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    Abstract The main subject of this article is the action research and it has as general objective to describe the construction of knowledge in this field from the uses that Brazilian Production Engineering makes of it, aiming to recognize its contributions, potentials and limits. To achieve this goal, a literature review was carried out for a subsequent contrast with the national academic researches that use action research and show its uses. Identified these similarities, a documentary research was carried out in academic papers published in the National Meeting of Production Engineering (ENEGEP) – from 1996 to 2010. The content analysis was the strategy used for data analysis and NVivo® software was used for its treatment. As a conclusion of the research, it can be stated that the use of action research in the Brazilian Production Engineering distances itself from epistemic precepts associated with it. The results of the action are more highlighted than the reflection on the mechanisms that produced i
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