54 research outputs found

    Preliminary study of an astropectinid (Asteroidea, Echinodermata) from the Lower Cretaceous (Mulichinco Formation) of the Neuquén Basin, Argentina

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    Body fossils of any group of starfish are rarely preserved; mostly they comprise dissociated ossicles only. Astropectinids in particular have a limited fossil record, although they are environmentally broad ranging and numerically important in recent settings. The Mulichinco Formation (Early Valanginian, Mendoza Group) is a clastic, mainly marine and marginal-marine succession, exposed in the Neuquén Province. The sample was recovered from the lowermost levels of this Formation, in the outcrops located along the National Road 40 at the Pampa Tril area (37º15'S, 69º47'W). The sandstone containing the specimen represents the top of one of several coarsening upward successions interpreted as shoreface deposits. The sample is a very well-preserved starfish in oral view. The central area (disk) and the five rays can be identified (two of them are complete, one is almost complete, and two are fractured showing less than a third of their original length). The ambulacral grooves, the inframarginal plates and some of the adambulacral plates corresponding to each of the rays are also observable. The members of the Astropectinidae family exhibit a rather small disc, long and normally straight-sided arms, and contact facets between marginals smaller than the sides of these ossicles. All of these features can be observed in the studied sample. The first records of the Astropectinidae come from Jurassic deposits. The only Mesozoic records of this family come from Europe and North America. This specimen represents, therefore, the first evidence of the existence of this group of starfish in the Cretaceous of South America.Sesiones libresFacultad de Ciencias Naturales y Muse

    Distinct monocyte subset phenotypes in patients with different clinical forms of chronic Chagas disease and seronegative dilated cardiomyopathy

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    BACKGROUND: Chronic infection with Trypanosoma cruzi leads to a constant stimulation of the host immune system. Monocytes, which are recruited in response to inflammatory signals, are divided into classical CD14hiCD16-, non-classical CD14loCD16+ and intermediate CD14hiCD16+ subsets. In this study, we evaluated the frequencies of monocyte subsets in the different clinical stages of chronic Chagas disease in comparison with the monocyte profile of seronegative heart failure subjects and seronegative healthy controls. The effect of the anti-parasite drug therapy benznidazole on monocyte subsets was also explored. METHODOLOGY/PRINCIPAL FINDINGS: The frequencies of the different monocyte subsets and their phenotypes were measured by flow cytometry. Trypanosoma cruzi-specific antibodies were quantified by conventional serological tests. T. cruzi-infected subjects with mild or no signs of cardiac disease and patients suffering from dilated cardiomyopathy unrelated to T. cruzi infection showed increased levels of non-classical CD14loCD16+ monocytes compared with healthy controls. In contrast, the monocyte profile in T. cruzi-infected subjects with severe cardiomyopathy was skewed towards the classical and intermediate subsets. After benznidazole treatment, non-classical monocytes CD14loCD16+ decreased while classical monocytes CD14hiCD16-increased. CONCLUSIONS/SIGNIFICANCE: The different clinical stages of chronic Chagas disease display distinct monocyte profiles that are restored after anti-parasite drug therapy. T. cruzi-infected subjects with severe cardiac disease displayed a profile of monocytes subsets suggestive of a more pronounced inflammatory environment compared with subjects suffering from heart failure not related to T. cruzi infection, supporting that parasite persistence might also alter cell components of the innate immune system

    Genotype by environment interaction and productive potential of 25 starch maize assessed at the Tayacaja Province, Peru

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    La interacción genotipo por ambiente (IGA) representa el principal obstáculo en la selección de los genotipos promisorios para diversos ambientes. El objetivo de esta investigación fue evaluar la IGA y el potencial productivo de 25 variedades de maíz amiláceo, utilizando el modelo de efectos principales aditivos e interacción multiplicativa (AMMI). Se utilizó la información generada en cinco ensayos establecidos en diferentes localidades de la provincia de Tayacaja, Huancavelica, Perú, en el ciclo del cultivo 2018–2019, bajo un diseño alfa látice 5x5, con tres repeticiones y unidades experimentales de dos hileras de 4 m de longitud, con arreglos espaciales de 0,80 m entre hileras y 0,20 m entre puntos de siembra. El potencial productivo de los cultivares se midió a través del rendimiento de grano, ajustado a 15 % de humedad. Definida la IGA, se realizó el análisis multivariado, para obtener los valores singulares de los primeros términos significativos del modelo para genotipos y ambientes. La IGA resultó altamente significativa y explicó alrededor del 14 % de la variación fenotípica del rendimiento, mostrando algunas variedades con adaptación específica y otras con amplia adaptación a los ambientes de prueba. El modelo AMMI explicó alrededor del 96 % de la variación debida a la IGA, observándose que sólo los dos primeros ejes concentraron cerca del 85 % de dicha variación. Las variedades locales Chullpi-Q, Carhuay-P, Astilla Blanca-Cusqueado, Astilla Blanca-DH, Cusqueado-P y Astilla Blanca-Astilla Amarilla mostraron el mejor potencial productivo, pero sólo las tres primeras fueron estables a través de los ambientes de evaluación

    The family Carditidae (Bivalvia) in the early Danian of Patagonia (Argentina)

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    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

    Cheek Tooth Morphology and Ancient Mitochondrial DNA of Late Pleistocene Horses from the Western Interior of North America: Implications for the Taxonomy of North American Late Pleistocene Equus

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    Horses were a dominant component of North American Pleistocene land mammal communities and their remains are well represented in the fossil record. Despite the abundant material available for study, there is still considerable disagreement over the number of species of Equus that inhabited the different regions of the continent and on their taxonomic nomenclature. In this study, we investigated cheek tooth morphology and ancient mtDNA of late Pleistocene Equus specimens from the Western Interior of North America, with the objective of clarifying the species that lived in this region prior to the end-Pleistocene extinction. Based on the morphological and molecular data analyzed, a caballine (Equus ferus) and a non-caballine (E. conversidens) species were identified from different localities across most of the Western Interior. A second non-caballine species (E. cedralensis) was recognized from southern localities based exclusively on the morphological analyses of the cheek teeth. Notably the separation into caballine and non-caballine species was observed in the Bayesian phylogenetic analysis of ancient mtDNA as well as in the geometric morphometric analyses of the upper and lower premolars. Teeth morphologically identified as E. conversidens that yielded ancient mtDNA fall within the New World stilt-legged clade recognized in previous studies and this is the name we apply to this group. Geographic variation in morphology in the caballine species is indicated by statistically different occlusal enamel patterns in the specimens from Bluefish Caves, Yukon Territory, relative to the specimens from the other geographic regions. Whether this represents ecomorphological variation and/or a certain degree of geographic and genetic isolation of these Arctic populations requires further study

    Innovación en las enseñanzas universitarias: experiencias presentadas en las III Jornadas de Innovación Educativa de la ULL

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    En este libro se recoge un conjunto de experiencias de innovación educativa desarrolladas en la ULL en el curso 2011-12. Se abordan distintos ámbitos y ramas del conocimiento, y ocupan temáticas variadas que han sido desarrolladas con rigor, y con un claro potencial para su extrapolación a efectos de la mejora educativa en el ámbito universitario. Esta publicación constituye una primera edición de una serie que irá recogiendo las experiencias de innovación educativa de la ULL. Este es un paso relevante para su impulso en nuestra institución, como lo es el de su vinculación con la investigación educativa, para potenciar su publicación en las revistas científicas en este ámbito cada vez más pujante y relevante para las universidades. Sobre todo representan el deseo y el compromiso del profesorado de la ULL para la mejora del proceso educativo mediante la investigación, la evaluación y la reflexión compartida de nuestras prácticas y planteamientos docentes
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