Cartridge Case and Bullet Comparison : Examples of Evaluative Reporting

This paper presents examples of how to report results when using a probabilistic approach in the field of firearms. Three European Institutes who have adopted a Likelihood Ratio (LR) -based approach in their practice were asked to produce the evaluation section of a report based on a fictious case. Background information about the Institutes, their conclusion scales, and reporting formats is presented. The article ends with a brief overview of recent developments within the ENFSI (European Network of Forensic Science Institutes) community where guidelines for evaluative reports have been formulated and are now published. The current collaborative approach between Institutes, presented in this article, offers an opportunity to discuss practical issues related to this approach. More specifically, this is an opportunity to introduce the ENFSI guidelines and its tenets, providing more tools for firearms/toolmarks examiners to progress toward a LR-based approach

Predation as the primary selective force in recurrent evolution of gigantism in Poecilozonites land snails in Quaternary Bermuda

During the last half million years, pulses of gigantism in the anagenetic lineage of land snails of the subgenus Poecilozonites on Bermuda were correlated with glacial periods when lower sea level resulted in an island nearly an order of magnitude larger than at present. During those periods, the island was colonized by large vertebrate predators that created selection pressure for large size and rapid growth in the snails. Extreme reduction in land area from rising seas, along with changes in ecological conditions at the onset of interglacial episodes, marked extinction events for large predators, after which snails reverted to much smaller size. The giant snails were identical in morphology during the last two glacials when the predators included a large flightless rail Rallus recessus (marine isotope stages (MIS) 4-2) and a crane Grus latipes and a duck Anas pachysceles (MIS 6). In a preceding glacial period (MIS 10), when the fauna also included the tortoise Hesperotestudo bermudae, the snails were not only large, but the shells were much thicker, presumably to prevent crushing by tortoises. Evolution of Poecilozonites provides an outstanding example of dramatic morphological change in response to environmental pressures in the absence of cladogenesis