Non-hexagonal-ring defects and structures induced by strain in graphene and in functionalized graphene

We perform {\textit ab initio} calculations for the strain-induced formation of non-hexagonal-ring defects in graphene, graphane (planar CH), and graphenol (planar COH). We find that the simplest of such topological defects, the Stone-Wales defect, acts as a seed for strain-induced dissociation and multiplication of topological defects. Through the application of inhomogeneous deformations to graphene, graphane and graphenol with initially small concentrations of pentagonal and heptagonal rings, we obtain several novel stable structures that possess, at the same time, large concentrations of non-hexagonal rings (from fourfold to elevenfold) and small formation energies

ANESTRO pós-parto em ovelhas deslanadas.

Anestro; Fases em que ocorre o anestro; Principais fatores que influenciam a duração do anestro pós-parto; Efeitos da amamentação no retorno ao estro pós-parto; Efeitos da nutrição no retorno ao estro pós-parto; Práticas de manejo que contribuem para antecipar o estro pós-parto. Equipe Técnica: Tânia Maria Leal, Maria do Perpétuo Socorro Cortez Bona do Nascimento, Raimundo Bezerra de Araújo Neto, Raimundo Bezerra de Araújo Neto, Adriana Mello de Araújo.bitstream/item/52990/1/FDAnestro0001.pd

Gravitational lensing by a Lorentz-violating black hole

In this work, we study the gravitational lensing by a Lorentz-violating (LV) black hole inspired by the recent contribution [1]. Explicitly, we concentrate on a specific application: we perform the computation of gravitational lensing effects under the strong field limit. In particular, we analytically derive the deflection angle so that the lens equation can also be addressed. This methodological approach yields physically measurable outcomes, including the determination of relativistic image positions and their corresponding magnifications. As an application of this methodology, we consider the gravitational lensing by Sagittarius A${}^*$ and obtain the corresponding observables expressed as functions of the LV parameter.Comment: 22 pages, minor corrections, references adde

Vacuum solution within a metric-affine bumblebee gravity

We consider a metric-affine extension to the gravitational sector of the Standard-Model Extension for the Lorentz-violating coefficients $u$ and $s^{\mu\nu}$. The general results, which are applied to a specific model called metric-affine bumblebee gravity, are obtained. A Schwarzschild-like solution, incorporating effects of the Lorentz symmetry breaking through coefficient $X=\xi b^2$, is found. Furthermore, a complete study of the geodesics trajectories of particles has been accomplished in this background, emphasizing the departure from general relativity. We also compute the deflection of light within the context of the weak field approximation and verify that there exist two new contributions ascribed to the Lorentz symmetry breaking. As a phenomenological application, we compare our theoretical results with observational data in order to estimate the coefficient $X$.Comment: 22 pages, 5 figure

O capim-massai no Meio-Norte.

bitstream/CPAMN-2009-09/16886/1/CT142.pd