An index of biotic integrity based on the summer polyhaline zooplankton community of the Chesapeake Bay

A zooplankton index of biotic integrity was developed for the polyhaline waters of the Chesapeake Bay using data from a long-term environmental assessment program in which both zooplankton and water quality were regularly monitored. Summer (July to September) sampling events were classified as either coming from impaired or reference (least-impaired) conditions based on water quality conditions. Seventeen zooplankton community metrics were evaluated under these criteria and nine were chosen for a composite index. These were the Simpson diversity index, and abundance of barnacle larvae, rotifers, cladocerans, copepods, total mesozooplankton, and predators. The composite index of biotic integrity correctly classified about 94% of the impaired samples and about 82% of the reference samples. Average classification efficiency was 88%. This index appears to be an effective measure of eutrophication for the summer polyhaline waters of the Chesapeake Bay ecosystem.

Molecular systematics of Selene (Perciformes: Carangidae) based on cytochrome B sequences

The marine fishes of the genus Selene are morphologically unique, although little is known about how these species are related to other members of the family Carangidae (Perciformes). In addition, questions remain about the potential validity of two putative species and how species groups with unique body forms within Selene are related. We used DNA sequences of the mitochondrial cytochrome b gene to reconstruct the phylogeny of the seven species of Selene along with five additional species of carangids. Maximum-likelihood and maximum-parsimony analyses were used to examine the sequence data and both phylogenetic methods were compared. Maximum-likelihood produced a monophyletic Selene, whereas parsimony analyses did not. Both maximum-likelihood and maximum-parsimony produced similar support for species groups within Selene. Maximum-likelihood produced two monophyletic subgroups within the genus Selene, the "long-finned" and "short-finned" Selene. Maximum-parsimony produced the same monophyletic "long-finned" group but a paraphyletic "short-finned" group. Both analyses confirm that S. brownii and S. setapinnis are distinct species, expunging the question of conspecificity. The phylogenetic placement of the most basal taxon within Selene, S. orstedii, was problematic and differed among analyses. More data are needed to resolve with confidence its correct phylogenetic placement and, thus, the monophyly of the genus Selene.

Quality assessment of amalgam and inlay restorations on posterior teeth: a retrospective study

This study was designed to assess and compare the quality of posterior proximo-occlusal amalgam and inlay restorations relative to type of restoration (material, surfaces involved, and cusp protection) and length of service of the restorations. A clinical evaluation system based on operationally defined and clinically important criteria was used. Clinically and statistically significant differences were found between overall ratings for amalgam and inlay restorations and between small (two-surface) amalgam and inlay restorations, as well as between larger (three-surface) amalgam and inlay restorations. In all cases, inlay restorations were of higher quality. A not acceptable rating for marginal integrity was the most frequent reason for not acceptable overall ratings. There was no difference in satisfactory/not acceptable ratings for inlay restorations with or without protected cusps (p = .95).