Harbour porpoises (Phocoena phocoena) stranding in large numbers around the southern North Sea with fatal, sharp-edged mutilations have spurred controversy among scientists, the fishing industry and conservationists, whose views about the likely cause differ. The recent detection of grey seal (Halichoerus grypus) DNA in bite marks on three mutilated harbour porpoises, as well as direct observat...

A gray seal (Halichoerus grypus) was trained to touch a target on its left or right by responding to pointing signals. The authors then tested whether the seal would be able to generalize spontaneously to altered signals. It responded correctly to center pointing and head turning, center upper body turning, and off-center pointing but not to head turning and eye movements alone. The seal also r...

introduction: the purpose of this in-vitro study was to investigate the influence of the remaining calcium hydroxide (ch) as an intracanal dressing on the apical sealing ability of three endodontic sealers. materials and methods: sixty-six single and straight canals of recently extracted human permanent maxillary central incisors were used. all canals were prepared and sixty of them were random...

The predatory cladoceran Cercopagis pengoi has extended its range over the past decade from the Ponto-Caspian basin into the Baltic Sea and the Laurentian Great Lakes. This study employs mitochondrial DNA (mtDNA) sequence analysis to elucidate the invasion corridors exploited during this range expansion. The Caspian and Black Sea populations of C. pengoi exhibit marked genetic divergence, enabl...

Aim Impacts of invasive species may vary across invasion gradients, owing to trait-based sorting of individuals through dispersal: those aggregating at invasion fronts may be more aggressive and voracious. We examine, in the field and laboratory, variation in the predatory impacts of an invasive Ponto-Caspian crustacean Hemimysis anomala G.O. Sars, 1907 at two sites along a spatiotemporal gradi...

An in vitro study was performed to ascertain the marginal seal elemental composition of amalgam restored extracted teeth of known marginal leakage. Occlusal cavities were cut in 400 caries free extracted teeth and left unlined or lined with one of 5 bases. A varnish was applied to half the cavities followed by restoration with a low copper or high copper amalgam to produce 20 restoration combin...