48 research outputs found
New early Triassic Lingulidae (Brachiopoda) genera and species from South China
Two new genera, Sinolingularia gen. nov. and Sinoglottidia gen. nov., together with three new species, Sinolingularia huananensis gen. et sp. nov., Sinolingularia yini gen. et sp. nov. and Sinoglottidia archboldi gen. et sp. nov., are described on the basis of a large collection of well-preserved specimens from several sections straddling the Permian - Triassic boundary in South China. <br /
An edrioasteroid from the Silurian Herefordshire Lagerstätte of England reveals the nature of the water vascular system in an extinct echinoderm
The family Carditidae (Bivalvia) in the early Danian of Patagonia (Argentina)
The first systematic analysis of the Danian carditids of Patagonia is presented, which includes four genera—one new genus and the first records of three other genera in South America. They consist of Claibornicardia paleopatagonica (Ihering, 1903), a widely distributed species occuring in the Jagüel, Roca and Salamanca formations (Neuquén, Río Negro and Chubut Provinces); Rotundicardia Heaslip, 1968, represented by the new species R. mariobrosorum n. sp., which is restricted to the Roca Formation (Río Negro Province); Cardites feruglioi (Petersen, 1846) (Roca and Lefipán formations, Río Negro and Chubut Provinces); and by Kalelia new genus, which includes K. burmeisteri (Böhm, 1903) from the Salamanca and Roca formations (Río Negro and Chubut Provinces), which is related to the Paris Basin species K. multicostata (Lamarck, 1806) n. comb. and K. pectuncularis (Lamarck, 1806) n. comb. ‘Venericardia’ iheringi (Böhm, 1903), a species known only from internal molds, is described and regarded as a carditid with uncertain affinities. The presence of Claibornicardia, Rotundicardia, and Cardites in Patagonia constitutes the most ancient record of these genera and confirms biogeographical connections previously established between the Danian Argentinian and North American/European fossil faunas.Fil: Perez, Damián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; ArgentinaFil: del Río, Claudia Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; Argentin
The Origin and Initial Rise of Pelagic Cephalopods in the Ordovician
BACKGROUND: During the Ordovician the global diversity increased dramatically at family, genus and species levels. Partially the diversification is explained by an increased nutrient, and phytoplankton availability in the open water. Cephalopods are among the top predators of today's open oceans. Their Ordovician occurrences, diversity evolution and abundance pattern potentially provides information on the evolution of the pelagic food chain. METHODOLOGY/PRINCIPAL FINDINGS: We reconstructed the cephalopod departure from originally exclusively neritic habitats into the pelagic zone by the compilation of occurrence data in offshore paleoenvironments from the Paleobiology Database, and from own data, by evidence of the functional morphology, and the taphonomy of selected cephalopod faunas. The occurrence data show, that cephalopod associations in offshore depositional settings and black shales are characterized by a specific composition, often dominated by orthocerids and lituitids. The siphuncle and conch form of these cephalopods indicate a dominant lifestyle as pelagic, vertical migrants. The frequency distribution of conch sizes and the pattern of epibionts indicate an autochthonous origin of the majority of orthocerid and lituitid shells. The consistent concentration of these cephalopods in deep subtidal sediments, starting from the middle Tremadocian indicates the occupation of the pelagic zone early in the Early Ordovician and a subsequent diversification which peaked during the Darriwilian. CONCLUSIONS/SIGNIFICANCE: The exploitation of the pelagic realm started synchronously in several independent invertebrate clades during the latest Cambrian to Middle Ordovician. The initial rise and diversification of pelagic cephalopods during the Early and Middle Ordovician indicates the establishment of a pelagic food chain sustainable enough for the development of a diverse fauna of large predators. The earliest pelagic cephalopods were slowly swimming vertical migrants. The appearance and early diversification of pelagic cephalopods is interpreted as a consequence of the increased food availability in the open water since the latest Cambrian
Une méthode simplifiée de mesure du volume atrial gauche sur les scanners de score calcique. Cardiovasculaire diagnostique et interventionnel. Séance Cardiovasculaire diagnostique et interventionnel. Séance ''L21 - Imagerie cardiaque non invasive''
Objectifs : Evaluer une méthode simple et rapide de mesure du volume atrial gauche.
Matériels et méthodes : Cinquante patients ont été examinés avec un CT gaté pour mesure du score calcique. Trois méthodes ont été utilisées pour calculer le volume atrial gauche : 1) une méthode orthogonale avec mesure des surfaces/diamètres dans les plans axiaux/coronaux/sagittaux, 2) une méthode biplan inspirée de l'échocardiographie et 3) une méthode volumétrique. Les mesures ont été faites par le même observateur un mois plus tard et ont été répétées par trois autres observateurs. L'axe cardiaque a aussi été mesuré. La méthode Bland-Altmann et les corrélations de Spearman ont été utilisées.
Résultats : La méthode volumétrique montre les variations intra/interobservateur les plus basses avec une variabilité de 6,1/7,4 ml, respectivement. Pour les mesures avec la méthode orthogonale (surfaces/diamètres), les variations intra/interobservateur sont 12,3/13,5 ml et 14,6/11,6 ml, respectivement. Pour la méthode biplan, les variations intra/interobservateur sont plus hautes : 23,9/19,8 ml. Comparée à la méthode de référence volumétrique, la méthode orthogonale avec les surfaces est mieux corrélée (R=0,959, p<0,001) que les autres méthodes. Il y a une faible influence de l'axe du coeur sur la méthode orthogonale avec les surfaces.
Conclusion : La méthode volumétrique est le gold standard en terme de variabilité. Cependant elle est longue à metttre en oeuvre. La méthode orthogonale avec les surfaces est une alternative simple, sauf chez les patients obèses avec un coeur horizontalisé