Abundance and seasonality of Diptera (Insecta) in a poultry house in the northeast region of the state of Sao Paulo, Brazil

Modem production systems accommodate broody hens in high densities, leading to the accumulation of excrement under the cages. This substrate is excellent for the development of sinantropic flies. Thus, the accomplishment of surveys in these places becomes essential, in order to plan better strategies of control. The present work aimed at studying the entornofauna and the seasonality of the species of dipterous present in the Crisdan poultry house located in the Municipality of Sao Joao da Boa Vista, the State of Sao Paulo, Brazil. In the period of January of 2001 to December of 2002, 1,012,595 flies were captured using the ""jug-trap"". The species were identified: Drosophi-la repleta (Wollaston, 1858), Musca domestica (Linnaeus, 1758), Ophyra spp., Hennetria illucens (Linnaeus, 1758), Fannia canicularis (Linnaeus, 1761), Chrysomya megacephala (Fabricius, 1794), and Sepsidae. More frequently D. repleta and M. domestica had added 99.47% of the dipterous. Increased rainfall and the collection months influenced the sampling of dipterous (P < 0.05). Drosophila repleta was the most abundant species, representing 91% of all captured flies. However, this diptera did not develop at the surveyed site since immatures were not captured therein.

The competing roles of extensional viscosity and normal stress differences in complex flows of elastic liquids

In various attempts to relate the behaviour of highly-elastic liquids in complex flows to their rheometrical behaviour, obvious candidates for study have been the variation of shear viscosity with shear rate, the two normal stress differences N(1) and N(2) especially N(1), and the extensional viscosity eta(E). In this paper, we shall be mainly interested in `constant-viscosity` Boger fluids, and, accordingly, we shall limit attention to N(1) and eta(E). We shall concentrate on two important flows - axisymmetric contraction flow and ""splashing"" (particularly that which arises when a liquid drop falls onto the free Surface of the same liquid). Modem numerical techniques are employed to provide the theoretical predictions. It is shown that the two obvious manifestations of viscoelastic rheometrical behaviour can sometimes be opposing influences in determining flow characteristics. Specifically, in an axisymmetric contraction flow, high eta(E) , can retard the flow, whereas high N(1) can have the opposite effect. In the splashing experiment, high eta(E) can certainly reduce the height of the so-called Worthington jet, thus confirming some early suggestions, but, again, other rheometrical influences can also have a role to play and the overall picture may not be as clear as it was once envisaged.