The Quantum Stress-Tensor in Self-Similar Spherical Dust Collapse

We calculate the quantum stress tensor for a massless scalar field in the 2-d self-similar spherical dust collapse model which admits a naked singularity. We find that the outgoing radiation flux diverges on the Cauchy horizon. This may have two consequences. The resultant back reaction may prevent the naked singularity from forming, thus preserving cosmic censorship through quantum effects. The divergent flux may lead to an observable signature differentiating naked singularities from black holes in astrophysical observations.Comment: Latex File, 19 page

Curtimento de pele ovina passo a passo.

Cuidados a serem observados antes do curtimento; Primeira etapa do curtimento; Segunda etapa; Terceira etapa (lavagem e remolho); Quarta etapa (engraxamento); Quinta etapa (acabamento).bitstream/item/55740/1/it05-2000.pd

Respostas produtiva e fisiológica de vacas de cria nelore em pastejo à suplementação mineral e protéico-energética na seca.

Objetivos: monitorar o metabolismo ósseo de vacas durante o ciclo reprodutivo, caracterizando os períodos de reabsorção/reposição de osso e estudar a resposta óssea à suplementação de nutrientes durante fases definidas do ciclo reprodutivo.bitstream/item/137708/1/PESQ-EM-ANDAMENTO-53.pdfCNPGC

COVID-19: o que o avicultor precisa saber.

bitstream/item/212047/1/final9420.pd

Bose Condensation and the BTZ Black Hole

Although all popular approaches to quantum gravity are able to recover the Bekenstein-Hawking entropy-area law in the thermodynamic limit, there are significant differences in their descriptions of the microstates and in the application of statistics. Therefore they can have significantly different phenomenological implications. For example, requiring indistinguishability of the elementary degrees of freedom should lead to changes in the black hole's radiative porperties away from the thermodynamic limit and at low temperatures. We demonstrate this for the Ba\~nados-Teitelboim-Zanelli (BTZ) black hole. The energy eigenstates and statistical entropy in the thermodynamic limit of the BTZ black hole were obtained earlier by us via symmetry reduced canonical quantum gravity. In that model the BTZ black hole behaves as a system of Bosonic mass shells moving in a one dimensional harmonic trap. Bose condensation does not occur in the thermodynamic limit but this system possesses a finite critical temperature, $T_c$, and exhibits a large condensate fraction below $T_c$ when the number of shells is finite.Comment: 5 pages, 5 figures. Published versio

Statistical Mechanics of Two-dimensional Foams

The methods of statistical mechanics are applied to two-dimensional foams under macroscopic agitation. A new variable -- the total cell curvature -- is introduced, which plays the role of energy in conventional statistical thermodynamics. The probability distribution of the number of sides for a cell of given area is derived. This expression allows to correlate the distribution of sides ("topological disorder") to the distribution of sizes ("geometrical disorder") in a foam. The model predictions agree well with available experimental data