1,098 research outputs found

    Las nuevas excavaciones (1995-2006) en el yacimiento del Mioceno final de Venta del Moro, Valencia

    Get PDF
    Se presenta una síntesis preliminar de la metodología y de los principales resultados obtenidos en las nuevas campañas de excavación (1995-2006) en la localidad clásica de vertebrados del Mioceno final (Turoliense superior, MN13) de Venta del Moro (Valencia, España). Destaca la actualización de la lista faunística, con la incorporación de más de una decena de taxones de vertebrados no citados anteriormente en el yacimiento. Así, si consideramos sólo la asociación de mamíferos, el listado se compone, por el momento, de 43 taxones. Además, se presentan las listas provisionales de otros grupos, como los moluscos, y se cita por vez primera el hallazgo de foraminíferos.From 1995 until 2006 new paleontological excavations were carried out at Venta del Moro (Valencia, Spain), one of the classical Uppermost Miocene (Upper Turolian, MN 13) vertebrate locality of Spain. In the present paper a preliminary synthesis of the methods and main results are presented. Abundant faunal remains were recovered including ten vertebrate taxa no previously recorded from the site. Up to now 43 mammalian species are known from the site. Preliminary list of others groups, as mollusc, are given. The occurrence of foraminifera is reported for the first [email protected] [email protected] [email protected] [email protected] [email protected]

    Bose-Einstein condensate dark matter phase transition from finite temperature symmetry breaking of Klein-Gordon fields

    Full text link
    In this paper the thermal evolution of scalar field dark matter particles at finite cosmological temperatures is studied. Starting with a real scalar field in a thermal bath and using the one loop quantum corrections potential, we rewrite Klein-Gordon's (KG) equation in its hydrodynamical representation and study the phase transition of this scalar field due to a Z_2 symmetry breaking of its potential. A very general version of a nonlinear Schr\"odinger equation is obtained. When introducing Madelung's representation, the continuity and momentum equations for a non-ideal SFDM fluid are formulated, and the cosmological scenario with the SFDM described in analogy to an imperfect fluid is then considered where dissipative contributions are obtained in a natural way.Additional terms appear compared to those obtained in the classical version commonly used to describe the \LambdaCDM model, i.e., the ideal fluid. The equations and parameters that characterize the physical properties of the system such as its energy, momentum and viscous flow are related to the temperature of the system, scale factor, Hubble's expansion parameter and the matter energy density. Finally, some details on how galaxy halos and smaller structures might be able to form by condensation of this SF are given.Comment: Substantial changes have been made to the paper, following the referees recommendations. 16 pages. Published in Classical and Quantum Gravit

    Las nuevas excavaciones (1995-2006) en el yacimiento del Mioceno final de Venta del Moro, Valencia

    Get PDF
    From 1995 until 2006 new paleontological excavations were carried out at Venta del Moro (Valencia, Spain), one of the classical Uppermost Miocene (Upper Turolian, MN 13) vertebrate locality of Spain. In the present paper a preliminary synthesis of the methods and main results are presented. Abundant faunal remains were recovered including ten vertebrate taxa no previously recorded from the site. Up to now 43 mammalian species are known from the site. Preliminary list of others groups, as mollusc, are given. The occurrence of foraminifera is reported for the first time.Se presenta una síntesis preliminar de la metodología y de los principales resultados obtenidos en las nuevas campañas de excavación (1995-2006) en la localidad clásica de vertebrados del Mioceno final (Turoliense superior, MN13) de Venta del Moro (Valencia, España). Destaca la actualización de la lista faunística, con la incorporación de más de una decena de taxones de vertebrados no citados anteriormente en el yacimiento. Así, si consideramos sólo la asociación de mamíferos, el listado se compone, por el momento, de 43 taxones. Además, se presentan las listas provisionales de otros grupos, como los moluscos, y se cita por vez primera el hallazgo de foraminíferos

    Presence of Mammuthus sp. from Caravaca (Murcia)

    Get PDF
    In Rambla del Pizcalejo (Caravaca, Murcia, Spain) new Proboscidea fossil remains were found. In this paper are described all postcranial bones belonging to a 2-4 years old Mammuthus. Stratigraphycal and mollusc data confirm the lacustrine paleoenvironment. The remains shouldn’t have suffered a hard transport; neither should their time of exposure have been long. The date of the remains is not precise due to the lack of chronostratigraphic and biostratigraphic data. It is only the assignment of the remains to the genus Mammuthus that allows to surmise a period about Plio-Pleistocen

    La fauna del pleistoceno inferior de la sierra de Quibas (Abanilla, Murcia)

    Get PDF
    El yacimiento kárstico cuaternario de la Sierra de Quibas (Abanilla, Murcia) ha proporcionado una amplia lista faunística constituida por 53 especies repartidas entre gasterópodos, miriápodos, anfibios, reptiles, aves y mamíferos. En el conjunto de los gasterópodos destaca Palaeoglandina, un género que se extingue en el resto de Europa durante el Plioceno y que se mantiene como relicto en el Pleistoceno de la Península Ibérica. Dos de las especies de aves determinadas, Gypaetus barbatus y Gerontieus eremita, y una de las serpientes, Elaphe cf. E. sealaris, apenas se hallan representadas en el registro fósil. Hay además varias especies de aves cuya aparición en Quibas supone la primera cita en el Pleistoceno inferior de la Península Ibérica. Entre los mamíferos posee una especial relevancia la presencia del cercopitécido Macaca sylvanus. La asociación de los taxones Arvieola deuealíon, Castillomys rivas rivas, Elíomys intermedius, Equus altidens y Capra sp. aff. C. alba permite la correlación con Plines 1, Orce 3 y Venta Micena, entre otros. El yacimiento de Quibas puede situarse, por tanto, antes del final del Pleistoceno inferior, con una antigüedad entre 1.3 y 1 Ma. Por lo que se refiere a las condiciones paleoclimáticas, podemos inferir a partir de la asociación faunística un régimen xerófilo, muy semejante al actual en el área geográfica, aunque quizás con valores de humedad y temperatura algo superiores. El entorno de la cavidad kárstica estaba formado por roquedo calcáreo con áreas abiertas de matorral, pero en las proximidades se desarrollaron humedales y zonas arboladas, como así lo atestigua la presencia de aves y micromamíferos típicos de estos hábitats.The Quaternary karstic site of Sierra de Quibas (Abanilla, Murcia, Spain) has provided a wide faunallist with 53 species distributed among gastropods, myriapods, amphibians, reptiles, birds and mammals. Especially interesting among the gastropods is Palaeoglandina that became extinct in Europe during the Pliocene. It remains as a relict genus in the Pleistocene of the Iberian Peninsula. Two of the birds, Gypaetus barbatus and Geronticus eremita, and a snake, Elaphe cf. E. sealaris, are scarcely represented in the fossil record. For several birds, it is the first record in the Lower Pleistocene of the Iberian Peninsula. Among the mammals, the presence of the Cercopithecine Macaca sylvanus is especially relevant. The assemblage of the taxa Arvicola deucalion, Castillomys rivas rivas, Eliomys intermedius, Equus altidens and Capra sp. aff. C. alba allows the correlation with Plines 1, Orce 3 and Venta Micena, among other sites. Therefore Quibas can be clated before the end of Lower Pleistocene, between 1.3 and 1 Ma. A dry paleoclimatic regime, very similar to the current climate in the geographical area, though perhaps slightly wetter and warmer, can be inferred from the faunal assemblage. The environment of the karstic cavity was a rocky place with open brushwood areas, but in the proximities there were wetlands and woodlands, as can be inferred from the presence of birds and micromammals characteristic of these [email protected] [email protected]

    Kretzoiarctos gen. nov., the Oldest Member of the Giant Panda Clade

    Get PDF
    The phylogenetic position of the giant panda, Ailuropoda melanoleuca (Carnivora: Ursidae: Ailuropodinae), has been one of the most hotly debated topics by mammalian biologists and paleontologists during the last century. Based on molecular data, it is currently recognized as a true ursid, sister-taxon of the remaining extant bears, from which it would have diverged by the Early Miocene. However, from a paleobiogeographic and chronological perspective, the origin of the giant panda lineage has remained elusive due to the scarcity of the available Miocene fossil record. Until recently, the genus Ailurarctos from the Late Miocene of China (ca. 8–7 mya) was recognized as the oldest undoubted member of the Ailuropodinae, suggesting that the panda lineage might have originated from an Ursavus ancestor. The role of the purported ailuropodine Agriarctos, from the Miocene of Europe, in the origins of this clade has been generally dismissed due to the paucity of the available material. Here, we describe a new ailuropodine genus, Kretzoiarctos gen. nov., based on remains from two Middle Miocene (ca. 12–11 Ma) Spanish localities. A cladistic analysis of fossil and extant members of the Ursoidea confirms the inclusion of the new genus into the Ailuropodinae. Moreover, Kretzoiarctos precedes in time the previously-known, Late Miocene members of the giant panda clade from Eurasia (Agriarctos and Ailurarctos). The former can be therefore considered the oldest recorded member of the giant panda lineage, which has significant implications for understanding the origins of this clade from a paleobiogeographic viewpoint

    Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

    Get PDF
    A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

    Search for New Physics with Jets and Missing Transverse Momentum in pp collisions at sqrt(s) = 7 TeV

    Get PDF
    A search for new physics is presented based on an event signature of at least three jets accompanied by large missing transverse momentum, using a data sample corresponding to an integrated luminosity of 36 inverse picobarns collected in proton--proton collisions at sqrt(s)=7 TeV with the CMS detector at the LHC. No excess of events is observed above the expected standard model backgrounds, which are all estimated from the data. Exclusion limits are presented for the constrained minimal supersymmetric extension of the standard model. Cross section limits are also presented using simplified models with new particles decaying to an undetected particle and one or two jets
    corecore