615 research outputs found
A new species of Dryornis (Aves, Cathartiformes) from the Santa Cruz Formation (lower Miocene), Patagonia, Argentina
No full textThe Santa Cruz Formation (lower Miocene) has one of the richest fossil assemblages in South America (Vizcaíno et al., 2012). Fossils were first collected in the 19th century, when the expeditions carried out by Francisco P. Moreno and Carlos Ameghino resulted in the discovery of different species, mainly mammals. This Cenozoic fauna caught the attention of William B. Scott of Princeton University (U.S.A.) who trusted John B. Hatcher to lead the expeditions to Patagonia between 1896 and 1899. Hatcher visited different localities in the Santa Cruz province, mainly on the Atlantic coast, spending less time in the outcrops along the Santa Cruz River and in the Andean region (Fernícola et al., 2019). After collecting a large amount of specimens, he returned to the U.S.A., where the material was deposited in the paleontological collections of the Peabody Museum (New Haven) and the American Museum of Natural History (New York). Taking into account that some of the materials were fragmentary or poorly visited and consulted, the phylogenetic affinities of some of the remains are still a subject of debate...Fil: Degrange, Federico Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentin
COURANTS NEUTRES ET CHARME DANS LES INTERACTIONS DE NEUTRINOS
No full textDepuis quatre ans, la Physique du Neutrino a connu deux développements importants : l'étude des processus dus aux courants neutres faibles et l'étude de la production de particules charmées par des neutrinos. Pour illustrer les progrès expérimentaux accomplis dans ces domaines jusqu'en juin 1977, nous présentons dans cet article quelques résultats choisis parmi les plus marquants
The reaction with two neutral weak bosons at LEP energies
No full textThe model independent formulae giving the cross-section, the charge asymmetry and the longitudinal polarization of the final leptons are given for reaction. The general features of models based on the group are summarized. The predictions of two of them are presented for the reaction
Les observations gamma au sol de noyaux actifs de galaxie : les experiences CAT & CELESTE
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