As abelhas Irapuá (Trigona spinipes) podem contribuir com a polinização da romãzeira (Punica granatum)?.

O objetivo deste trabalho foram avaliar se ocorre autopolinização na romãzeira e se estas abelhas podem contribuir efetivamente para a sua polinização

Vacuum fluctuations of a scalar field near a reflecting boundary and their effects on the motion of a test particle

The contribution from quantum vacuum fluctuations of a real massless scalar field to the motion of a test particle that interacts with the field in the presence of a perfectly reflecting flat boundary is here investigated. There is no quantum induced dispersions on the motion of the particle when it is alone in the empty space. However, when a reflecting wall is introduced, dispersions occur with magnitude dependent on how fast the system evolves between the two scenarios. A possible way of implementing this process would be by means of an idealized sudden switching, for which the transition occurs instantaneously. Although the sudden process is a simple and mathematically convenient idealization it brings some divergences to the results, particularly at a time corresponding to a round trip of a light signal between the particle and the wall. It is shown that the use of smooth switching functions, besides regularizing such divergences, enables us to better understand the behavior of the quantum dispersions induced on the motion of the particle. Furthermore, the action of modifying the vacuum state of the system leads to a change in the particle energy that depends on how fast the transition between these states is implemented. Possible implications of these results to the similar case of an electric charge near a perfectly conducting wall are discussed.Comment: 17 pages, 8 figure

Relation between high at nest entrance and diameter of trees which serve as nesting sites for Melipona mandacaia (Apidae, Meliponini).

The aim of this study was to investigate details on natural nesting sites as the high of the nests' entrance and relation of this and the Diameter at Breast Height (DBH)