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Search Results: 1 - 10 of 12843 matches for " Marcelo; Parras "
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Métodos alternativos de optimización de la geometría de estructuras articuladas
Parras, Luis
Informes de la Construccion , 1983,
"Poetic Prose and Imperialism: The Ideology of Form in Joseph Conrad's Heart of Darkness"
John Parras.
Nebula , 2006,
Darwin's great patagoniantertiary formation at the mouth of the río Santa Cruz: a reappraisal La Gran Formación Terciaria Patagónica de Darwin enla desembocadura del río Santa Cruz: una revaluación
Ana Parras,Miguel Griffin
Revista de la Asociación Geológica Argentina , 2009,
Abstract: Theclassical section described by Darwin at the mouth of the Río Santa Cruz was alandmark in the later stratigraphy of the marine Cenozoic of Patagonia.Sedimentological and paleontological studies of rocks from the Monte LeónFormation at the Darwin and Mount Entrance sections - mouth of the Río SantaCruz - suggest that they were deposited in an early Miocene inner shelf tosubtidal - or even intertidal at the top - environment. The base of thesections is covered and the top is unconformably overlain by Quaternarydeposits. The invertebrate fauna (mainly mollusks) mentioned herein - theearliest of which were collected by Darwin and described by Sowerby - werecollected from the two sections with a detailed stratigraphic control. Itincludes brachiopods, echinoderms, scaphopods, bivalves, and gastropods. Thesimilarity of this fauna with that one from the sections at Restinga Norte,Cabeza de León, Las Cuevas, Yegua Quemada and Monte Observación, all south ofthe study area, allow correlation with them. In addition to the equivalence ofthe faunas, sedimentological features at all these localities are also thesame. Therefore, all the shell beds involved should be referred to the PuntaEntrada Member of the Monte León Formation. The Monte Observación Member shouldbe restricted to its original use and included as a member at the base of theoverlying Santa Cruz Formation, outcrops at Cerro Monte León and CerroObservación. La sección clásica descripta por Darwin en la desembocaduradel río Santa Cruz fue un hito en el posterior desarrollo de la estratigrafíadel Cenozoico marino de Patagonia. Los estudios sedimentológicos ypaleontológicos realizados en sedimentitas de la Formación Monte León, en las secciones Darwin y Monte Entrada, en el área de la desembocaduradel río Santa Cruz, sugieren que las mismas fueron depositadas en un ambientede plataforma interna a submareal en la base, hasta intermareal en el techo,durante el Mioceno temprano. La base de las secciones se encuentra cubierta y sutecho es cortado en forma discordante por depósitos del Cuaternario. La faunade invertebrados (mayormente moluscos) mencionada en este trabajo, cuyosprimeros representantes fueran coleccionados por Darwin y descriptos porSowerby, fue colectada con un detallado control estratigráfico a lo largo delas dos secciones. La misma incluye braquiópodos, equinodermos, escafópodos,bivalvos y gasterópodos. La similitud en la composición taxonómica, como asítambién en las características sedimentológicas, entre estas secciones yaquellas ubicadas más al sur como son Restinga Norte, Cabeza de León,
Situación del sida en Espa a: presente y perspectivas futuras
Parras Vázquez Francisco
Revista Espa?ola de Salud Pública , 1997,
Análisis de estructuras planas canónicas mediante ordenadores de peque a capacidad de memoria
Parras Galán, Luis
Informes de la Construccion , 1984,
Abstract: In this study a method is developed which will enable canonical flat structures containing numerous elements to be analyzed, using computers with a small capacity of central memory and without the necessity of a peripheral memory. The field of application for these structures is in jointed beams (Warren, Pratt types, etc.), roof frames, canopies, etc., which are those most widely used in the world of a rural and industrial engineering. Consider, for example, the different agricultural instalattions in which these structures are used, such as warehouses for storing machinery, the storage of agricultural products, industrial and cattle-raising installations, etc. En el presente trabajo se desarrolla un método que permite el análisis de estructuras planas canónicas de gran número de elementos, con ordenadores de peque a capacidad de memoria central y sin requerimiento de memoria periférica. Dichas estructuras tienen su campo de aplicación en vigas articuladas (tipo Warren, Pratt, etc.), cerchas, marquesinas, etc., que son las que con mayor profusión se utilizan en el mundo de la ingeniería rural e industrial. Piénsese, por ejemplo, en las distintas instalaciones agrícolas en las que se utilizan dichas estructuras como son las naves para el resguardo de maquinaria, almacenamiento de productos agrarios, instalaciones industriales, ganaderas, etc.
Distribución de Lutzomyia longipalpis en el Chaco Argentino, 2010
Salomón,Oscar D.; Rosa,Juan R.; Fabiani,Mariela; San Miguel,Silvia R.; Szelag,Enrique A.; Nepote,Marcelo; Parras,Matías A.;
Medicina (Buenos Aires) , 2011,
Abstract: the appearance of the vector of visceral leishmaniasis (vl) lutzomyia longipalpis in the province of formosa in 2004 was associated with urban epidemic risk for the first time in argentina. during 2006, vectors, canine and human cases of vl were reported in the province of misiones, and in summer 2008-2009, in the province of corrientes. in santiago del estero province in 2008, cases of human and canine vl were associated with secondary vectors. therefore, with the aim to know the current distribution of vl risk in the chaco region, systematic captures of the vector were performed between january and april 2010 in 30 localities of formosa and chaco, and in the city of reconquista, province of santa fe (224 traps/night). lu. longipalpis was reported for the first time in the cities of resistencia and puerto antequera (chaco). clorinda and puerto pilcomayo (formosa) are the localities where the traps with more individuals were obtained, 158 and 241 lu. longipalpis trap / site / night respectively. these results showed that the vector of urban epidemic vl is still spreading in argentina, and already reached the province of chaco. sporadic cases reported in the chaco region, transmitted by secondary vectors as lu. migonei would also increase due to intensified surveillance, and the dispersion of the parasite associated with the transit of asymptomatic or symptomatic infected dogs.
Endoscopia en pacientes antiagregados Endoscopy in antiaggregated patients
Fernando Alberca de las Parras
Revista Espa?ola de Enfermedades Digestivas , 2012,
Un plesiosaurio de cuello corto (Plesiosauroidea, Polycotylidae) del Cretácico Superior del norte de Patagonia
Salgado,Leonardo; Parras,Ana; Gasparini,Zulma;
Ameghiniana , 2007,
Abstract: several plesiosaur vertebrae found in the allen formation (late campanian-early maastrichtian; upper cretaceous), at loma puntuda locality, salitral de santa rosa, río negro province, argentina, are described. some anatomical features, such as the amphicoelous vertebral centres higher rather than longer, a ring surrounding the posterior articular surface of the cervical vertebrae, a ventral keel in the cervical vertebrae, the cervical neural spines expanded distally and probably inclined posteriorly, and the lateral surfaces of the dorsal bodies strongly compressed, justify their assignation to the polycotylidae, a short-necked plesiosauroid group relatively frequent in the upper cretaceous of north america. this is the first record of postcranial remains of a polycotylid in south america, where these plesiosaurs were known only by cranial and mandibular remains (assigned to sulcusuchus erraini gasparini and spalletti) found in equivalent stratigraphic levels (campanian-maastrichtian), in the chubut and río negro provinces.
Late Maastrichtian-Danian Mytilids and Pinnids (Mollusca: Bivalvia) from Northern Patagonia, Argentina
Griffin,Miguel; Parras,Ana; Casadío,Silvio;
Ameghiniana , 2008,
Abstract: the upper cretaceous - lower paleogene rocks from northern patagonia yield a rich fauna of marine mollusks that may be useful in elucidating paleobiogeographic and paleoenvironmental changes taking place across the k/p boundary in the region. most of the mollusk faunas remain poorly understood, as the preservation is generally deficient. this paper describes three new species of mytilids (septifer mayai n. sp., mytilaster ? edseli n. sp. and gregariella amara n. sp.), and records four species of pinnids, one of which is new (plesiopinna pampeana n. sp.). all the material comes from the maastrichtian jagüel formation, and the maastrichtian/danian roca formation, exposed in the provinces of río negro, mendoza and la pampa (argentina). a survey of the stratigraphic distribution of the material described shows that the only maastrichtian species that survived into the danian was gregariella amara.
Maastrichtian and Danian species of Turkostreini (Ostreidae, Crassostreinae) from the Neuquén Basin, Argentina
Griffin,Miguel; Casadío,Silvio; Parras,Ana;
Ameghiniana , 2005,
Abstract: the record of turkostrea damboreneae nom. nov. and cubitostrea primordialis n. sp. in the maastrichtian jagüel and roca formations and of turkostrea argentina n. sp., in the danian beds of the roca formation reveals that the two genera involved have a history that reaches back into the late cretaceous in northern patagonia. turkostrea damboreneae nom. nov. and cubitostrea primordialis n. sp. are the two oldest representatives of the genera in which they belong. the two species of turkostrea show clear affinities with other species of this genus that thrived in the paleogene of the northern hemisphere. cubitostrea primordialis n. sp. is closely allied to the previously known paleocene species common in the region. while turkostrea appears to have survived the cretaceous/paleogene boundary, it is not found in patagonia in rocks younger than danian. cubitostrea also survived the cretaceous/paleogene boundary but, although for diverse reasons absent from eocene-oligocene rocks in southern south america, is again common in early and late miocene sediments exposed at various localities there. based on these records, the possible south american origin of the turkostreini is discussed.
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