Species Review of Amphibian Extinction Risks in Madagascar: Conclusions from the Global Amphibian Assessment

We assessed the extinction risks of Malagasy amphibians by evaluating their distribution, occurrence in protected areas, population trends, habitat quality, and prevalence in commercial trade. We estimated and mapped the distribution of each of the 220 described Malagasy species and applied, for the first time, the IUCN Red List categories and criteria to all species described at the time of the assessment. Nine species were categorized as critically endangered, 21 as endangered, and 25 as vulnerable. The most threatened species occur on the High Plateau and/or have been subjected to overcollection for the pet trade, but restricted extent of occurrence and ongoing habitat destruction were identified as the most important factors influencing extinction threats. The two areas with the majority of threatened species were the northern Tsaratanana-Marojejy-Masoala highlands and the southeastern Anosy Mountains. The current system of protected areas includes 82% of the threatened amphibian species. Of the critically endangered species, 6 did not occur in any protected area. For conservation of these species we recommend the creation of a reserve for the species of the Mantella aurantiaca group, the inclusion of two Scaphiophryne species in the Convention on the International Trade in Endangered Species Appendix II, and the suspension of commercial collecting for Mantella cowani . Field surveys during the last 15 years reveal no pervasive extinction of Malagasy amphibians resulting from disease or other agents, as has been reported in some other areas of the world.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75394/1/j.1523-1739.2005.00249.x.pd

A review of perspectives on the use of randomization in phase II oncology trials

Historically, phase II oncology trials assessed a treatment’s efficacy by examining its tumor response rate in a single-arm trial. Then, approximately 25 years ago, certain statistical and pharmacological considerations ignited a debate around whether randomized designs should be utilized instead. Here, based upon an extensive literature review, we review the arguments on either side of this debate. In particular, we describe the numerous factors that relate to the reliance of single-arm trials on historical control data, and detail the trial scenarios in which there was general agreement on preferential utilization of single-arm or randomized design frameworks, such as the use of single-arm designs when investigating treatments for rare cancers. We then summarize the latest figures on phase II oncology trial design, contrasting current design choices against historical recommendations on best practice. Ultimately, we find several ways in which the design of recently completed phase II trials does not appear to align with said recommendations. For example, despite advice to the contrary, only 66.2% of the assessed trials that employed progression-free survival as a primary or co-primary outcome used a randomized comparative design. In addition, we identify that just 28.2% of the considered randomized comparative trials came to a positive conclusion, as opposed to 72.7% of the single-arm trials. We conclude by describing a selection of important issues influencing contemporary design, framing this discourse in light of current trends in phase II, such as the increased use of biomarkers and recent interest in novel adaptive designs

La crise des overdoses américaines : une menace pour la France ?

International audienc

Essais de caractérisation dynamique des matériaux aux vitesses moyennes de déformation

International audienceL’exposé s’intéresse au moyen le plus conventionnel de caractérisation dynamique des matériaux, à savoir la machine d’essai hydraulique. On pourrait penser que ces essais sont aujourd’hui parfaitement maîtrisés, ce qui est vrai dans le domaine des sollicitations quasi-statiques où ils sont même normalisés. Ce n’est toujours pas le cas dans le domaine des sollicitations moyennes vitesses (avant le domaine d’application des barres de Hopkinson), alors que ces essais s’avèrent indispensables pour plusieurs raisons qui sont mise en évidence dans le papier. L’exposé rappelle dans un premier temps et dans les grandes lignes quelles sont les capacités et les limitations actuelles de ces vérins hydrauliques rapides. Il adresse ensuite, au-delà des limitations des moyens, plusieurs sources de difficultés qui peuvent – si l’on n’y prend pas garde – rendre caduque tout espoir d’atteindre une caractérisation dynamique intrinsèque du comportement des matériaux testés. Sont évoquées plusieurs questions qui semblent majeures, les pièges et les précautions à prendre pour les éviter : définition des éprouvettes de caractérisation, introduction des efforts dynamiques, instrumentation, acquisition et mesure, et enfin traitement et exploitation de ces essais. En conclusion, après que les principaux acquis du laboratoire CRD de l’ONERA/DADS sur ces questions depuis 30 ans aient été rappelés, sont présentées quelques perspectives et voies d’amélioration aujourd’hui explorées pour adresser les nouveaux défis et les enjeux pour le secteur aéronautique dans ce domaine

Armoured vehicles subject to mine explosions – an analysis method for operationability and survivability

The paper deals with numerical methodologies to improve the operationability and survivability of armoured vehicle subject to mine explosions. Methods are proposed to model and extract the time history of the impulsive load from a mine explosion, and to restore equivalent loading conditions to a structural analysis calculation. The problem of computing the shock transmitted to the floor through the undercarriage in the case of the explosion of a mine under a wheel is finally investigated. That kind of model enables to discriminate whether the highly dynamic shock is transmitted through the wheel/undercarriage, or directly through the floor