14,693 research outputs found

    Analytical approach to directed sandpile models on the Apollonian network

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    We investigate a set of directed sandpile models on the Apollonian network, which are inspired on the work by Dhar and Ramaswamy (PRL \textbf{63}, 1659 (1989)) for Euclidian lattices. They are characterized by a single parameter qq, that restricts the number of neighbors receiving grains from a toppling node. Due to the geometry of the network, two and three point correlation functions are amenable to exact treatment, leading to analytical results for the avalanche distributions in the limit of an infinite system, for q=1,2q=1,2. The exact recurrence expressions for the correlation functions are numerically iterated to obtain results for finite size systems, when larger values of qq are considered. Finally, a detailed description of the local flux properties is provided by a multifractal scaling analysis.Comment: 7 pages in two-column format, 10 illustrations, 5 figure

    Travel of studies: cities of João Pessoa, Maceio, Natal and Recife: a look on the urban space and brazilian architectural production

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    Ponencia presentada a Session 8: Dimensiones psicosociales de la arquitectura y el urbanismo / Psycological dimensions of architecture and planningThis article aims to present the methodology and the final results of the elective course “Travel of Studies” which belongs to the new pedagogical project from the Architecture and Urbanism course at the University Federal of Pernambuco. It was offered for the first time in 2013.The discipline was organized to occur in four long weekends through visits of four capitals of the Northeast of Brazil: Recife, João Pessoa, Natal and Maceió. The purpose was to allow the students to apprehend the cities through four axis: intervention in historical center (axis 1), production of urban space (axis 2), production of coastline space (axis 3) and contemporary architecture (axis 4). After the four visits were complete, we prepared a poster with the comparison of the cities based on the identification of the similarities and differences of each axis we have studied

    Efficient formalism for large scale ab initio molecular dynamics based on time-dependent density functional theory

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    A new "on the fly" method to perform Born-Oppenheimer ab initio molecular dynamics (AIMD) is presented. Inspired by Ehrenfest dynamics in time-dependent density functional theory, the electronic orbitals are evolved by a Schroedinger-like equation, where the orbital time derivative is multiplied by a parameter. This parameter controls the time scale of the fictitious electronic motion and speeds up the calculations with respect to standard Ehrenfest dynamics. In contrast to other methods, wave function orthogonality needs not be imposed as it is automatically preserved, which is of paramount relevance for large scale AIMD simulations.Comment: 5 pages, 3 color figures, revtex4 packag

    On bare masses in time-symmetric initial-value solutions for two black holes

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    The Brill-Lindquist time-symmetric initial-value solution for two uncharged black holes is rederived using the Hamiltonian constraint equation with Dirac delta distributions as a source for the binary black-hole field. The bare masses of the Brill-Lindquist black holes are introduced in a way which is applied, after straightforward modification, to the Misner-Linquist binary black-hole solution.Comment: LaTeX, 4 page

    Renormalization of the N=1 Abelian Super-Chern-Simons Theory Coupled to Parity-Preserving Matter

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    We analyse the renormalizability of an Abelian N=1 super-Chern-Simons model coupled to parity-preserving matter on the light of the regularization independent algebraic method. The model shows to be stable under radiative corrections and to be gauge anomaly free.Comment: Latex, 7 pages, no figure

    On neglected taxa: Protostomes and the evolution of myelination

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    Understanding the evolution of nervous and sensory systems in animals is key to understanding the distribution of animal sentience. However, the use of model organisms – mostly vertebrates, and especially mammals – often biases comparative analyses. Sneddon et al. (2018a,b) point out that using nonhuman animals as models helps us better understand the multifaceted aspects of animal pain and sentience. Several concerns need to be considered in dealing with model organisms. Here we discuss how models that are unrepresentative phylogenetically influence hypotheses about the evolution of the myelination in animals. Greater effort is needed to escape “vertebrate-centrism” in evolutionary research
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