Quasinormal modes of plane-symmetric black holes according to the AdS/CFT correspondence

The electromagnetic and gravitational quasinormal spectra of $(3+1)$-dimensional plane-symmetric anti-de Sitter black holes are analyzed in the context of the AdS/CFT correspondence. According to such a correspondence, the electromagnetic and gravitational quasinormal frequencies of these black holes are associated respectively to the poles of retarded correlation functions of $R$-symmetry currents and stress-energy tensor in the holographically dual conformal field theory: the $(2+1)$-dimensional $\mathcal{N}=8$ super-Yang-Mills theory. The connection between AdS black holes and the corresponding field theory is used to unambiguously fix the boundary conditions that enter the proper definition of quasinormal modes. Such a procedure also helps one to decide, among the various different possibilities, what are the appropriate gauge-invariant quantities one should use in order to correctly describe the electromagnetic and gravitational blackhole perturbations. These choices imply in different dispersion relations for the quasinormal modes when compared to some of the results in the literature. In particular, the long-distance, low-frequency limit of dispersion relations presents the characteristic hydrodynamic behavior of a conformal field theory with the presence of diffusion, shear, and sound wave modes. There is also a family of purely damped electromagnetic modes which tend to the bosonic Matsubara frequencies in the long-wavelength regime.Comment: 39 pages; added references; corrected typos; changed content in section

A Proactive Approach to the Translation of Bible Stories for Children

This paper presents cognitive poetics as an agent in overcoming difficulties in translating bible stories for young children in the multi-lingual and multi-cultural South African environment. The translated picture book texts typically involve the integration of words with pictures. For the purposes of this article, the Genesis 28 narrative of Jacob’s dream in the Hebrew source text is compared in various South African translations. Religious literature was chosen as subject matter because of the relative certainty of comparative translations in most of the eleven official languages of South Africa, but the present article is limited mainly to English and Afrikaans translations. The analysis is done within the fairly new framework of cognitive poetics, which combines psychological and cognitive linguistic approaches to the study of literature. The focus is on the contribution of cognitive linguistics to the translation of children’s literature, in the spirit of proactive translatology.Cet essai traite de la poésie cognitive comme facilitateur dans les traductions des histoires bibliques pour enfants dans l’environnement multiculturel et polyglotte de l’Afrique du Sud. Les traductions des textes des livres illustrés font généralement correspondre les mots avec des images. Dans l’exemple utilisé, soit la Genèse 28, le rêve de Jacob, dans son texte original en hébreu, est comparé à diverses traductions sud-africaines. La littérature religieuse a été choisie comme sujet de cet essai, étant donné la présence probable de traductions comparables dans la plupart des onze langues officielles de l’Afrique du Sud, mais cet article se limite à la comparaison des traductions anglaise et afrikaans seulement. L’analyse est faite dans le cadre relativement récent de la poésie cognitive, qui applique des approches linguistiques psychologique et cognitive à l’étude de la littérature. La concentration se fait sur la contribution de la linguistique cognitive dans la traduction de la littérature pour enfants dans un esprit de traduction proactive

MillionTreesNYC, Green Infrastructure and Urban Ecology Symposium March 5-6, 2010

The MillionTreesNYC Subcommittee on Research and Evaluation was formed shortly following the 2007 launch of MillionTreesNYC, a citywide, public-private initiative with an ambitious goal: to plant and care for one million new trees across New York City’s five boroughs by 2017. Members of this committee are comprised of academics, government researchers and local practitioners with experience in the fields of natural resource management and community development. On March 5-6, 2010, over two hundred researchers and practitioners came together at The New School to showcase scientific innovation in the field of urban forestry and greening. The MillionTreesNYC, Green Infrastructure and Urban Ecology Research Symposium engaged professionals from a broad range of disciplines including sociology, planning, epidemiology, earth sciences, hydrology, forestry, ecology, and design who were uniquely positioned to discuss new ideas

Quasinormal modes of black holes in anti-de Sitter space: a numerical study of the eikonal limit

Using series solutions and time-domain evolutions, we probe the eikonal limit of the gravitational and scalar-field quasinormal modes of large black holes and black branes in anti-de Sitter backgrounds. These results are particularly relevant for the AdS/CFT correspondence, since the eikonal regime is characterized by the existence of long-lived modes which (presumably) dominate the decay timescale of the perturbations. We confirm all the main qualitative features of these slowly-damped modes as predicted by Festuccia and Liu (arXiv:0811.1033) for the scalar-field (tensor-type gravitational) fluctuations. However, quantitatively we find dimensional-dependent correction factors. We also investigate the dependence of the QNM frequencies on the horizon radius of the black hole (brane) and the angular momentum (wavenumber) of vector- and scalar-type gravitational perturbations.Comment: 5 pages, RevTex4. v2: References added and minor typos corrected. Published versio