Comment on "some exact quasinormal frequencies of a massless scalar field in Schwarzschild spacetime"

© 2019 American Physical Society. A new branch of quasinormal modes for a massless scalar field propagating on the Schwarzschild spacetime was recently announced [D. Batic, M. Nowakowski, and K. Redway, Phys. Rev. D 98, 024017 (2018)PRVDAQ2470-001010.1103/PhysRevD.98.024017]. We review the quasinormal modes characterization and arguments and identify the flaws in their proof. Then, we preset explicit counterexamples to such arguments. Finally, we study the modes via alternative methods and do not find the new branch. We conclude against their interpretation

Morphological characteristics of an Amazon floodplain lake (Lake Batata, Pará State, Brazil)

A bathymetric survey of an Amazon floodplain lake adjacent to the Trombetas River, the Lake Batata (Pará State, Brazil), was done in order to characterize the lake morphology. This study serve as a tool for limnological interpretation data and in environmental impact assessment due to the disposal of tailings from bauxite processing. Lake area, volume, shoreline lenght, maximum effective length and width, shoreline development, maximum, relative and mean depth, volume development and a hypsographic curve were calculated. Lake Batata is shallow (mean depth 2.19 m) and its area is approximately 18 km² at low water level. Based on the configuration of the shoreline, the lake can be divided into differents compartments: the main body, the bay, the channel and the outlet. The basin of the lake is slightly convex with a typical U-shaped configuration. The lake is submitted to a significant seasonal variation of its surface area and shoreline lenght. The distribution of maximum effective fetch, at the main body, is coincident with the maximum turbidity values, evidencing the wind effect over the lake

Variações diurnas da emissão de CO2, temperatura e umidade do solo sobre diferentes manejos pós-colheita da cana-de-açúcar.

bitstream/item/69062/1/098-moitinho-variacoes.pdfPublicado também no Cadernos de Agroecologia, v. 7, n.2, 2012

Litter Decomposition of Xaraes-Grass Pasture Subjected to Different Post-Grazing Residuals

Since fertilizers are used less extensively on Xaraes-grass (Brachiaria brizantha) pastures in Brazil because of costs, the main route of nitrogen (N) supply to plants is through nutrient recycling via litter decomposition. One of the strategies used to maintain the supply of N is to manage the pasture correctly by keeping it under grazing pressure so that the amount of recycled nutrients in the residue is sufficient to meet the pasture requirements (Jantalia et al.2006). Thus, the aim of this study was to evaluate different residual leaf area indices (RLAI) and determine which one provides the best restoration of pasture leaf area index and nutrient cycling

Hyperboloidal slicing approach to quasinormal mode expansions: The Reissner-Nordström case

International audienceWe study quasinormal modes of black holes, with a focus on resonant (or quasinormal mode) expansions, in a geometric frame based on the use of conformal compactifications together with hyperboloidal foliations of spacetime. Specifically, this work extends the previous study of Schwarzschild in this geometric approach to spherically symmetric asymptotically flat black-hole spacetimes, in particular Reissner-Nordström. The discussion involves, first, the nontrivial technical developments needed to address the choice of appropriate hyperboloidal slices in the extended setting as well as the generalization of the algorithm determining the coefficients in the expansion of the solution in terms of the quasinormal modes. In a second stage, we discuss how the adopted framework provides a geometric insight into the origin of regularization factors needed in Leaver’s Cauchy-based foliations, as well as into the discussion of quasinormal modes in the extremal black-hole limit

Impact of trust on local residents' Mega-Event perceptions and their support

This study examines the influence of residents' trust in government and organizing committee on their impact perceptions and support for a mega-event, namely, 2014 FIFA World Cup. Findings suggest significant relationships between impact perceptions and support. While trust in government is found to be a significant determinant of impact perceptions, findings indicate no significant relationship between trust in government and support, which suggest that the relationship is mediated by impact perceptions. While a positive relationship between trust in the organizing committee and positive impact perceptions is found, findings suggest no significant relationship between trust in the organizing committee and negative impact perceptions. Trust in the organizing committee is also found to have significant positive impact on support.CNPq-Conselho Nacional de Desenvolvimento Cientifico e Tecnologico, Brasil (National Council for Scientific and Technological Development," Brazil)info:eu-repo/semantics/publishedVersio