Effects of parasites on larval and juvenile stages of the coral reef fish Pomacentrus moluccensis

The ecological role of parasites in the early life-history stages of coral reef fish is far from clear. Parasitism in larval, recently settled and juvenile stages of a coral reef fish damselfish (Pomacentridae) was therefore investigated by quantifying the ontogenetic change in parasite load and comparing the growth rates of parasitized juvenile fish to those of unparasitized ones. Parasite prevalence in two lunar pulses of Pomacentrus moluccensis was 4 and 0% for larval stage fish, 34 and 56% for recently settled fish and 42 and 49% for juveniles. A significant increase in parasite prevalence with age group was found; the most marked increase occurred immediately after larval fish had settled. Standard length did not model prevalence well; as length is a proxy for age, this indicates that the higher prevalence in recently settled and juvenile fish compared with larvae was not a simple result of parasites accumulating with age. In one of three cohorts, there was some evidence that parasitism affected the growth rate of juveniles, as measured by otolith width. The study suggests that settling on the reef exposes young fish to potentially harmful parasites. This supports the idea that the pelagic phase may have the effect of reducing the exposure of young fish to the debilitating effects of parasites

High-Tc superconductors toward small scale applications

This chapter discusses the applications of high-Tc superconductors (HTS), where Tc is the critical transition temperature between the superconductive and nonsuperconductive states. Various techniques for vortex visualization have also been proposed in the chapter. HTSs are layered materials and therefore anisotropic. This anisotropy depends on the fact that HTS materials are quasi-2D: CuO planes, with quasi-metallic conduction, separated by quasi-insulating blocking layers give the basic contribution to the superconductivity. The layered conductor is close to the metal-insulator transition so that any slight change in growing conditions as well as any extrinsic nanometric perturbation yields insulating zones in the CuO planes. The crystallographic structures are held together by electrons that form ionic or covalent bonds among the atoms. This property is usually considered a bad property, not only for the unwanted effects of these insulating plaques but also for the anisotropy aspect