Observing Long Cosmic Strings Through Gravitational Lensing

We consider the gravitational lensing produced by long cosmic strings formed in a GUT scale phase transition. We derive a formula for the deflection of photons which pass near the strings that reduces to an integral over the light cone projection of the string configuration plus constant terms which are not important for lensing. Our strings are produced by performing numerical simulations of cosmic string networks in flat, Minkowski space ignoring the effects of cosmological expansion. These strings have more small scale structure than those from an expanding universe simulation - fractal dimension 1.3 for Minkowski versus 1.1 for expanding - but share the same qualitative features. Lensing simulations show that for both point-like and extended objects, strings produce patterns unlike more traditional lenses, and, in particluar, the kinks in strings tend to generate demagnified images which reside close to the string. Thus lensing acts as a probe of the small scale structure of a string. Estimates of lensing probablity suggest that for string energy densities consistant with string seeded structure formation, on the order of tens of string lenses should be observed in the Sloan Digital Sky Survey quasar catalog. We propose a search strategy in which string lenses would be identified in the SDSS quasar survey, and the string nature of the lens can be confirmed by the observation of nearby high redshift galaxies which are also be lensed by the string.Comment: 24 pages revtex with 12 postscript firgure

The opportunistic behaviour of a common predator in aquatic systems in Amazonia: predation on robber-frog Pristimantis cf. fenestratus by trahira Hoplias malabaricus (Bloch, 1794)

Submitted by EMERSON LEAL ([email protected]) on 2019-06-12T20:22:48Z No. of bitstreams: 1 The opportunistic behavior of a common predator in aquatic systems in Amazonia An uncommon predation of trahira Hoplias malabaricus (Bloch, 1794).pdf: 1060465 bytes, checksum: 8b3521c6608994da9e9ec25b591a0fc3 (MD5)Approved for entry into archive by EMERSON LEAL ([email protected]) on 2019-06-12T20:54:33Z (GMT) No. of bitstreams: 1 The opportunistic behavior of a common predator in aquatic systems in Amazonia An uncommon predation of trahira Hoplias malabaricus (Bloch, 1794).pdf: 1060465 bytes, checksum: 8b3521c6608994da9e9ec25b591a0fc3 (MD5)Made available in DSpace on 2019-06-12T20:54:33Z (GMT). No. of bitstreams: 1 The opportunistic behavior of a common predator in aquatic systems in Amazonia An uncommon predation of trahira Hoplias malabaricus (Bloch, 1794).pdf: 1060465 bytes, checksum: 8b3521c6608994da9e9ec25b591a0fc3 (MD5) Previous issue date: 2017Programa de Pós-Graduação em Biodiversidade e Biotecnologia Bionorte. Porto Velho, RO, Brasil. / Centro de Estudos de Biomoléculas Aplicadas a Saúde. Departamento de Medicina. Porto Velho, RO, Brasil.Museu Nacional. Departamento de Vertebrados. Rio de Janeiro, RJ, Brasil.Universidade Federal de Rondônia. Porto Velho, RO, Brasil.Universidade Federal de Rondônia. Porto Velho, RO, Brasil.Centro de Estudos de Biomoléculas Aplicadas a Saúde. Departamento de Medicina. Porto Velho, RO, Brasil. / Fundação Oswaldo Cruz. Porto Velho, RO, Brasil. / Universidade Federal de Rondônia. Porto Velho, RO, Brasil.Anurans are considered extremely important animals for the food web, since they act as predators and prey for several animal species (Duellman and Trueb, 1994). The Neotropical rainfrogs of the genus Pristimantis (Terrarana: Craugastoridae) are distributed from Honduras through Central America and through Colombia and Ecuador to Peru, Bolivia, northern Argentina, and Amazonian and Atlantic Forests of Brazil, and in the Guianas, Trinidad and Tobago, Grenada, and the Lesser Antilles (Frost, 2016). These frogs are commonly found on the forest floor and on vegetation, and possess direct development (Heinicke et al., 2007; Hedges et al., 2008; Duellman and Lehr, 2009), which makes them independent of water bodies for oviposition or larval development. They are commonly found throughout the year among the leaf-litter or perched on shrubs up to two meters high, in habitats ranging from upland sites not subject to flooding to seasonally flooded areas (Duellman, 2005)