Metal content of the gulf of California blue shrimp Litopenaeus stylirostris (Stimpson).

The blue shrimp Litopenaeus stylirostris is the main target species of the Gulf of California shrimping fleet, and its heavy metal content might be of concern for human health because of the increasing contamination of the Gulf. The Cd content of shrimp caught by commercial trawlers ranged from 0.38 to 1.05 microg/g and the mean value was significantly lower in the northern fishing grounds. Pb ranged from 3.19 to 9.59 microg/g and was significantly higher in the northern area. There were no significant geographic difference in the case of Cu and Zn (respective means = 25.4 and 57.8 microg/g). The mean values of all metals show that none is of particular concern for human health.

Band gap of hexagonal 2D photonic crystals with elliptical holes recorded by interference lithography.

Two-dimensional hexagonal photonic crystals can be recorded using the simple superimposition of two interference patterns rotated by 60 masculine. Such process generates high contrast masks, however, it generates elliptical cross section structures instead of cylinders. We study the PBG properties of the experimentally feasible geometries, using this technique and we demonstrate that the effect of this asymmetric shape is a reduction in the PBG map area, for TE polarization, in comparison with cylindrical structures. On the other hand, it appears a PBG for TM polarization.