Robust estimation on a parametric model via testing

We are interested in the problem of robust parametric estimation of a density from $n$ i.i.d. observations. By using a practice-oriented procedure based on robust tests, we build an estimator for which we establish non-asymptotic risk bounds with respect to the Hellinger distance under mild assumptions on the parametric model. We show that the estimator is robust even for models for which the maximum likelihood method is bound to fail. A numerical simulation illustrates its robustness properties. When the model is true and regular enough, we prove that the estimator is very close to the maximum likelihood one, at least when the number of observations $n$ is large. In particular, it inherits its efficiency. Simulations show that these two estimators are almost equal with large probability, even for small values of $n$ when the model is regular enough and contains the true density.Comment: Published at http://dx.doi.org/10.3150/15-BEJ706 in the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

Estimating the conditional density by histogram type estimators and model selection

International audienceWe propose a new estimation procedure of the conditional density for independent and identically distributed data. Our procedure aims at using the data to select a function among arbitrary (at most countable) collections of candidates. By using a deterministic Hellinger distance as loss, we prove that the selected function satisfies a non-asymptotic oracle type inequality under minimal assumptions on the statistical setting. We derive an adaptive piecewise constant estimator on a random partition that achieves the expected rate of convergence over (possibly inhomogeneous and anisotropic) Besov spaces of small regularity. Moreover, we show that this oracle inequality may lead to a general model selection theorem under very mild assumptions on the statistical setting. This theorem guarantees the existence of estimators possessing nice statistical properties under various assumptions on the conditional density (such as smoothness or structural ones)

Controlled expansion and differentiation of mesenchymal stem cells in a microcarrier based stirred bioreactor

Controlled expansion and differentiation of mesenchymal stem cells in a microcarrier based stirred bioreactor

Sobre la presencia de Prodentia litura (F.), y Utetheisa pulchella (L.), en Mallorca. (Insectos. Lepidópteros)

Abstract not availabl

Los tabánidos de Mallorca

Abstract not availabl

A new species of genus Lestes Leach, 1815 (Insecta, Odonata) from Miocene of Bellver de Cerdanya (Lérida)

[ES] Se describe la nueva especie fósil de insecto Lestes dianacompteae n. sp. del orden Odonata, perteneciente al género Lestes Leach, 1815, sobre un ala procedente del yacimiento de Coll de Saig, en Bellver de Cerdanya (Lérida, España), del piso Vallesiense (Mioceno). La especie es comparada con todas las fósiles del género Lestes y las actuales más parecidas de las regiones Paleártica y Etiópica. © 2014 SAM y CSIC[EN] A new fossil species of insect, Lestes dianacompteae, n. sp. of the order Odonata, belonging to the genus Lestes Leach, 1815, is described based on wing from the Vallesian (Miocene), of Coll de Saig, in Bellver de Cerdanya (Lérida, Spain). It is compared with all fossil species of the genus and with the nearest extant species, from the paleartic and ethiopian regions. © 2014 SAM y CSICPeer Reviewe

Aportaciones al conocimiento de la Timarcha balearica Gory

Abstract not availabl