The political and financial investments in the implementation of forensic DNA databases and the ethical issues related to their use and expansion justify inquiries into their performance and general utility. The main function of a forensic DNA database is to produce matches between individuals and crime scene stains, which requires a constant input of individual profiles and crime scene stains. This is conditioned, among other factors, by the legislation, namely the criteria for inclusion of profiles and the periods of time and conditions for their retention and/or deletion. This article aims to provide an overview of the different legislative models for DNA databasing in Europe and ponder if wider inclusion criteria – and, consequently, database size – translates into more matches between profiles of crime scene stains and included individuals (performance ratio). The legislation governing forensic DNA databases in 22 countries in the European Union was analysed in order to propose a typology of two major groups of legislative criteria for inclusion/retention of profiles that can be classified as having either expansive effects or restrictive effects. We argue that expansive criteria for inclusion and retention of profiles do not necessarily translate into significant gains in output performance.Electronic supplementary materialThe online version of this article (doi:10.1186/2195-7819-9-12) contains supplementary material, which is available to authorized users.

This paper describes a two-dimensional numerical model to solve the generalized Serre equations. --i order to solve the system of equations, written in the conservative form, we use an explicit finite-difference method based on the MacCormack time-splitting scheme. The numerical method and the computational model are validated by comparing one-and two-dimensional numerical solutions with theoretical and experimental results. Finally, the two-dimensional model (in a horizontal plane) is tested in a domain with complicated boundary conditions.

The extraordinary media coverage regarding the disappearance of the British 3-yearold Madeleine McCann emerges as an illustrative example of a 'public drama' and 'trial by media'. This article presents a comparative analysis of the perspectives and narrative devices employed by two Portuguese newspapers in establishing a dialogue with their respective audiences. High-profile mediatized criminal cases have the potential to linger in the public memory and become cultural references which may affect longterm public representations of crime and justice. Our analysis is limited to a sample of representative Portuguese newspapers. We found a basic distinction between 'quality' and 'popular' press which may be related to inherent differences of their market and implicit audiences. A distanced, neutral and reflexive style of the quality press contrasts with the construction of a sensationalistic narrative by the popular press. The latter provided the audience with a daily dose of vicarious participation in a criminal drama which developed into a trial by media, sustained by a rhetoric that encourages the audience to 'take sides'. Sensationalist media narratives can potentially undermine the principles of fair trial and the presumption of innocence. But they can also elicit relevant collective energies directed at starting processes of change.

Abstract:The use of DNA technologies for criminal investigation purposes illuminates an interplay of knowledge and expertise where meaning and relevance of biological traces are negotiated. Through the analysis of five criminal cases that took place in Portugal between 1995 and 2010, and where DNA technologies were used, this article will focus on the dialogues established between the police and the forensic laboratories. I will argue that, on the one hand, the police investigators uses of DNA technologies seek to legitimate and provide an external source of neutrality and objectivity to the constructed narratives surrounding the commission of a crime. On the other hand, laboratories and forensic experts engage in the delimitation and preservation of their professional autonomy by developing boundary work around their scientific expertise through the translation and conversion of criminal traces into scientific artifacts.

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