9,979 research outputs found

    First teuthid cephalopod from the Lower Jurassic of South America (Neuquén Basin, Argentina)

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    A new species of squid, Teudopsis jeletzkyi n. sp., is described from the Toarcian (Lower Jurassic) of the Los Molles Formation in Neuquen Province, central west Argentina. Fossil squids have thus far been unknown in the Mesozoic of South America. This species is the first record of the Order Teuthida in the Jurassic of South America

    The independence of control structures in abstract programming systems

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    AbstractAn instance of a control structure is a mapping which takes one or more programs into a new program whose behavior is based on that of the original programs. An instance of a control structure is effective iff it is effectively computable. In order to study the interrelationships of control structures, . we consider abstract programming systems (numberings of the partial recursive functions) in which some control structures, effective or otherwise, are present, but others are not. This paper uses the techniques of recursive function theory, including recursion theorems and priority arguments to prove the independence of certain control structures in abstract programming systems. For example, we have obtained the following results. In effective numberings of the partial recursive functions, the one-one effective Kleene recursion theorem and the one-one effective (partial) if-then-else control structure are independent, but together, they yield all effective control structures. In any effective numbering, the effective Kleene form of the double recursion theorem yields all effective control structures

    First teuthid cephalopod from the Lower Jurassic of South America (Neuquén Basin, Argentina)

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    A new species of squid, Teudopsis jeletzkyi n. sp., is described from the Toarcian (Lower Jurassic) of the Los Molles Formation in Neuquen Province, central west Argentina. Fossil squids have thus far been unknown in the Mesozoic of South America. This species is the first record of the Order Teuthida in the Jurassic of South America

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    Aerodynamic design optimization of wind turbine airfoils under aleatory and epistemic uncertainty

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    This paper presents different approaches to optimize wind turbine airfoils in an uncertain scenario. The approaches are specifically applied to the aerodynamic design optimization of a wind turbine airfoil accounting for the uncertainty in setting up the XFOIL's NCRIT constant: a parameter that is considered affected by a chain of aleatory and epistemic uncertainty. Subject to a set of aerodynamic and structural constraints, the uncertain response of the airfoil is optimized by means of both probability- and imprecise probability-based approaches. These solutions are compared with a reference airfoil optimized with a conventional design approach, in which the treatment of uncertainty is carried out in a simplistic fashion. Once evaluated in the probabilistic scenario, the airfoil designed with the conventional approach still achieves the largest aerodynamic efficiency mean. This airfoil is however affected by the largest performance sensitivity to NCRIT variations. The airfoils optimized by means of uncertainty-based approaches instead achieve larger performance robustness and reliability than the airfoil optimized with the conventional approach

    Implementación del Modelo Hidrodinámico Bidimensional TELEMAC-2D en un tramo del río Paraná Inferior

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    En este trabajo se presenta la implementación del modelo de simulación hidrodinámica bidimensional TELEMAC-2D en el tramo km 410-452 del río Paraná Inferior, empleando una grilla triangular irregular. Se crearon dos constituciones a partir de relevamientos batimétricos realizados en los años 2004-2006 y 2010-2012 y se efectuaron simulaciones para flujo permanente e impermanente. En flujo permanente se utilizaron caudales aforados comprendidos entre 11640 m3/s y 28600 m3/s, mientras que, en flujo impermanente se empleó la serie de caudales registrada en el período 01/01/2004 al 31/12/2004 y en el período 16/03/2015 al 15/03/2016 para cada constitución del modelo respectivamente. Las variables de ajuste fueron los niveles observados en los hidrómetros de Rosario (ROS-km 416) y Puerto San Martín (PSM-km 448), empleándose como parámetro de calibración el coeficiente de rugosidad de Manning. Además, las particiones de caudales en las cuatro bifurcaciones del tramo se compararon con las mediciones disponibles, junto con las variaciones de las áreas mojadas y las distribuciones de caudales específicos en distintas secciones transversales, observándose una variación en los dos primeros parámetros, mientras que el tercero permanece prácticamente estable.Universidad Nacional de Rosari

    Intrahepatic persistent fetal right umbilical vein: a retrospective study

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    Introduction: To appraise the incidence and value of intrahepatic persistent right umbilical vein (PRUV). Methods: This was a single-center study. Records of all women with a prenatal diagnosis of intrahepatic PRUV were reviewed. The inclusion criteria were women with gestational age greater than 13 weeks of gestation. Exclusion criteria were fetuses with situs abnormalities, due to the hepatic venous ambiguity, and extrahepatic PRUV. The primary outcome was the incidence of intrahepatic PRUV in our cohort. The secondary outcomes were associated malformations. Results: 219/57,079 cases (0.38%) of intrahepatic PRUV were recorded. The mean gestational age at diagnosis was 21.8 ± 2.9 weeks of gestations. PRUV was isolated in the 76.7%, while in 23.3% was associated with other major or minor abnormalities. The most common associated abnormalities were cardiovascular abnormalities (8.7%), followed by genitourinary abnormalities (6.4%), skeletal abnormalities (4.6%), and central nervous system abnormalities (4.1%). Within the cardiovascular abnormalities, the most common one was ventricular septal defect (six cases). Conclusion: In most cases PRUV is an isolated finding. Associated minor or major malformations are presented in the 23.3% of the cases, so this finding should prompt detailed prenatal assessment of the fetus, with particular regard to cardiovascular system
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