Changes to the Fossil Record of Insects through Fifteen Years of Discovery

The first and last occurrences of hexapod families in the fossil record are compiled from publications up to end-2009. The major features of these data are compared with those of previous datasets (1993 and 1994). About a third of families (>400) are new to the fossil record since 1994, over half of the earlier, existing families have experienced changes in their known stratigraphic range and only about ten percent have unchanged ranges. Despite these significant additions to knowledge, the broad pattern of described richness through time remains similar, with described richness increasing steadily through geological history and a shift in dominant taxa, from Palaeoptera and Polyneoptera to Paraneoptera and Holometabola, after the Palaeozoic. However, after detrending, described richness is not well correlated with the earlier datasets, indicating significant changes in shorter-term patterns. There is reduced Palaeozoic richness, peaking at a different time, and a less pronounced Permian decline. A pronounced Triassic peak and decline is shown, and the plateau from the mid Early Cretaceous to the end of the period remains, albeit at substantially higher richness compared to earlier datasets. Origination and extinction rates are broadly similar to before, with a broad decline in both through time but episodic peaks, including end-Permian turnover. Origination more consistently exceeds extinction compared to previous datasets and exceptions are mainly in the Palaeozoic. These changes suggest that some inferences about causal mechanisms in insect macroevolution are likely to differ as well

Efficacy of psychedelics in animal models of binge drinking and alcohol use disorder

International audienc

Etude d’un dosimètre individuel passif multi-élément pour la dosimétrie des neutrons

La dosimétrie individuelle des neutrons est actuellement effectuée à partir de méthodes peu satisfaisantes, soit par l’utilisation d’émulsions nucléaires qui sont “aveugles” pour les énergies inférieures à 1.5 MeV, soit par la mise en œuvre de détecteurs à albédo qui doivent être étalonnés aux divers postes de travail car leur réponse varie considérablement en fonction de l’énergie des neutrons. Les auteurs présentent l’état actuel des études du projet DINEM, Dosimètre Individuel “Neutrons” à Eléments Multiples. Il est constitué d’un dosimètre à albédo “PGP-DIN” qui détecte les neutrons d’énergie inférieure à 7 keV et d’un détecteur solide de traces qui détecte les énergies supérieures à 100 keV. Les derniers progrès enregistrés sur l’utilisation du CN 85 comme détecteur solide de traces laissent entrevoir une solution prochaine au problème difficile de la dosimétrie individuelle