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Contains reports on three research projects

Ossos de pterosauro da Formação Portezuelo (Cretáceo), Grupo Neuquén, Patagônia, Argentina

The Futalognko quarry, located 90km northwest of Neuquén city, Argentina, has yielded several fossil vertebrates. All come from the upper part of the Portezuelo Formation (Turonian-Early Coniacian) and include some pterosaur remains, the first ones from the Cretaceous strata of the Neuquén Group. The material consists of a proximal end of a large ulna (MUCPv-358), the proximal part of a wing-phalanx (MUCPv-359), and another ulna associated with a radius (MUCPv-600). All specimens are referred to the Pterodactyloidea, and possibly represent members of the Azhdarchoidea. Histological sections of the large ulna (MUCPv-358) indicate that it belonged to an animal that was still growing at time of death. Comparisons with more complete specimens indicate that MUCPv-358 represents an animal with a wingspan of six meters, making it the largest pterosaur known from Argentina.O jazigo Futalognko está situado 90km a noroeste da cidade de Neuquén, Argentina, e forneceu uma grande quantidade de vertebrados fósseis, todos da parte superior da Formação Portezuelo (Turoniano- Eoconiaciano). Dentre os exemplares recuperados encontram-se alguns exemplares de pterossauros indicando a primeira ocorrência deste grupo para as rochas cretácicas do Grupo Neuquén. O material está representado pela parte proximal de uma ulna de grandes proporções (MUCPv-358), a parte proximal de uma primeira falange alar (MUCPv-359), e uma segunda ulna associada com o rádio (MUCPv-600). Todos estes exemplares são referidos a Pterodactyloidea e possivelmente representam formas de Azhdarchoidea. Seções histológicas da ulna maior (MUCPv-358) indicam que ela representa um animal jovem que estava em fase de crescimento quando morreu. Comparações com outros exemplares mais completos sugerem que MUCPv-358 tenha pertencido a um pterossauro com uma abertura alar em torno de seis metros, fazendo dele o maior réptil voador coletado até o presente momento na Argentina

The Fringe Detection Laser Metrology for the GRAVITY Interferometer at the VLTI

Interferometric measurements of optical path length differences of stars over large baselines can deliver extremely accurate astrometric data. The interferometer GRAVITY will simultaneously measure two objects in the field of view of the Very Large Telescope Interferometer (VLTI) of the European Southern Observatory (ESO) and determine their angular separation to a precision of 10 micro arcseconds in only 5 minutes. To perform the astrometric measurement with such a high accuracy, the differential path length through the VLTI and the instrument has to be measured (and tracked since Earth's rotation will permanently change it) by a laser metrology to an even higher level of accuracy (corresponding to 1 nm in 3 minutes). Usually, heterodyne differential path techniques are used for nanometer precision measurements, but with these methods it is difficult to track the full beam size and to follow the light path up to the primary mirror of the telescope. Here, we present the preliminary design of a differential path metrology system, developed within the GRAVITY project. It measures the instrumental differential path over the full pupil size and up to the entrance pupil location. The differential phase is measured by detecting the laser fringe pattern both on the telescopes' secondary mirrors as well as after reflection at the primary mirror. Based on our proposed design we evaluate the phase measurement accuracy based on a full budget of possible statistical and systematic errors. We show that this metrology design fulfills the high precision requirement of GRAVITY.Comment: Proc. SPIE in pres