Photometry of the Galactic bulge, collected during the OGLE-II microlensing search, indicates high and non-uniform interstellar extinction toward the observed fields. We use the mean I-band magnitude and V −I color of red clump stars as a tracer of interstellar extinction toward four small regions of the Galactic bulge with highly variable reddening. Similar test is performed for the most redde...

Stars form with a complex and highly structured distribution. For a smooth star cluster to form from these initial conditions, the star cluster must erase this substructure. We study how substructure is removed using N-body simulations that realistically handle two-body relaxation. In contrast to previous studies, we find that hierarchical cluster formation occurs chiefly as a result of scatter...

1. Abstract Sex differentiation is generally more labile in gonochoristic fish than it is, for example, in birds and mammals. Environmentally induced sex reversal is therefore often possible and creates genotype-phenotype mismatches that can be useful in population management. Interestingly, sex chromosomes of fish are typically not significantly decayed, i.e. all types of offspring of sex-reve...

Populations of reef fish are widely believed to be limited by availability of larval recruits, not by density dependent processes operating during and after settlement of young stages in the reef environment. Our research explores and challenges this thinking. We are utilizing field observations and experiments to determine what factors affect spatial distribution, abundance, and population dyn...

Fish disease surveys form a part of many biological monitoring programmes in European marine waters. Prevalence patterns of infectious diseases within wild fish populations are strongly influenced by the acquisition of immunity in individual fish. Hence, the interpretation of observed prevalence patterns requires understanding of the role of acquired immunity and immunomodulation in disease pop...

Submerged cultivation of Saccharopolyspora erythraea, at different initial spore concentrations, was carried out to study the inter-relationship between inoculum concentration, morphology, rheology and erythromycin production. Pellet morphology was dominant in runs at 10 and 10 spore/ml initial spore concentrations, whereas there was a significant presence of clump morphology in runs at initial...

Substructure in distant gravitational lens galaxies can be detected because it alters the brightnesses and shapes of the lensed images. The optical and radio flux ratios in the four-image lens B1422+231 imply that there is a ∼ 10–10 h M⊙ mass clump in the lens galaxy in front of image A; this is the first constraint on the mass of a particular clump lying in a distant galaxy and detected by its...

Some philosophers believe that two objects of value can be ‘roughly equal’, or ‘on a par’, or belong to the same ‘clump’ of value in a sense that is fundamentally different from that in which some objects are ‘better than’, ‘worse than’, or ‘equally as good as’ others. This article shows that if two objects are on a par, or belong to the same clump, then an agent accepting a few plausible premi...

—Hatchery-reared salmon have been reported to be inferior to wild fish in some studies and competitively superior in others. We examined the influence of early rearing environment (hatchery versus natural) on the summer survival, movement, and growth of genetically similar juvenile coho salmon Oncorhynchus kisutch in streams. In each of 2 years, 5,000–10,000 fry from a hatchery cohort were plac...