Optimal designs for multivariable spline models

In this paper, we investigate optimal designs for multivariate additive spline regressionmodels. We assume that the knot locations are unknown, so must be estimated from thedata. In this situation, the Fisher information for the full parameter vector depends on theunknown knot locations, resulting in a non-linear design problem. We show that locally,Bayesian and maximin D-optimal designs can be found as the products of the optimaldesigns in one dimension. A similar result is proven for Q-optimality in the class of allproduct design

Pion scattering in Wilson ChPT

We compute the scattering amplitude for pion scattering in Wilson chiral perturbation theory for two degenerate quark flavors. We consider two different regimes where the quark mass m is of order (i) a\Lambda_QCD^2 and (ii) a^2\Lambda_QCD^3. Analytic expressions for the scattering lengths in all three isospin channels are given. As a result of the O(a^2) terms the I=0 and I=2 scattering lengths do not vanish in the chiral limit. Moreover, additional chiral logarithms proportional to a^2\ln M_{\pi}^2 are present in the one-loop results for regime (ii). These contributions significantly modify the familiar results from continuum chiral perturbation theory.Comment: 20 pages, 4 figures. V3: Comments on finite size effects and the axial vector current added, one more reference. To be published in PR

Optimal designs for full and partial likelihood information — With application to survival models

Time-to-event data are often modelled through Cox’s proportional hazards model for which inference is based on the partial likelihood function. We derive a general expression for the asymptotic covariance matrix of Cox’s partial likelihood estimator for the covariate coefficients. Our approach is illustrated through an application to the special case of only one covariate, for which we construct minimum variance designs for different censoring mechanisms and both binary and interval design spaces. We compare these designs with the corresponding ones found using the full likelihood approach and demonstrate that the latter designs are highly efficient also for partial likelihood estimation

Les nouvelles lignes directrices du European Network of Forensic Sciences Institut en matière d’évaluation et de communication des résultats d’analyses et d’expertises scientifiques

Au printemps 2015, le European Network of Forensic Science Institutes a publié des lignes directrices visant à unifier les méthodes de travail des scientifiques agissant comme auxiliaires de la justice, plus précisément l’évaluation des résultats d’analyses scientifiques (logique du raisonnement) et la communication de ces résultats aux magistrats. Cette contribution a pour but d’expliciter ces lignes directrices et d’expliquer en quoi il est primordial que la justice suisse les adopte. — Im Frühjahr 2015 publizierte das ENFSI (European Network of Forensic Science Institutes) Leitlinien für die Vereinheitlichung wissenschaftlicher Arbeitsmethoden, insbesondere für Bewertung von wissenschaftlichen Untersuchungsergebnissen (Logik der Befundbewertung) und die Berichterstattung zuhanden der Justiz. Dieser Beitrag erläutert diese Richtlinien und erklärt, weshalb es wichtig ist, dass sie in die Schweizer Justizpraxis Eingang finden