Generalized Galilean Algebras and Newtonian Gravity

The non-relativistic versions of the generalized Poincar\'{e} algebras and generalized $AdS$-Lorentz algebras are obtained. This non-relativistic algebras are called, generalized Galilean algebras type I and type II and denoted by $\mathcal{G}\mathfrak{B}_{n}$ and $\mathcal{G}\mathfrak{L}_{_{n}}$ respectively. Using a generalized In\"{o}n\"{u}--Wigner contraction procedure we find that the generalized Galilean algebras type I can be obtained from the generalized Galilean algebras type II. The $S$-expansion procedure allows us to find the $\mathcal{G}\mathfrak{B}_{_{5}}$ algebra from the Newton--Hooke algebra with central extension. The procedure developed in Ref. \cite{newton} allow us to show that the non-relativistic limit of the five dimensional Einstein--Chern--Simons gravity is given by a modified version of the Poisson equation. The modification could be compatible with the effects of Dark Matter, which leads us to think that Dark Matter can be interpreted as a non-relativistic limit of Dark Energy.Comment: 16 pages, no figures in 755 (2016) 433-43

Diseño de Metodologías Activas para Másteres

El objetivo de la Universidad de Burgos desde el Máster en Inspección, Restauración, Rehabilitación y Eficiencia Energética de Edificación (MIREE), es la implementación de metodologías docentes activas con el fin de la formación del alumnado, a través de casos concretos y reales que adicionalmente reportarán un beneficio social. Alguno de estos métodos pueden ser el estudio de casos, la resolución de ejercicios y problemas, el aprendizaje basado en problemas y orientado a proyectos, el aprendizaje cooperativo, etc. Lo que pretendemos con las metodologías activas de aprendizaje es, que los alumnos adquieran las competencias propuestas en el programa docente, desarrollando un aprendizaje profundo en cada una de ellas. Para ello debemos evitar que el profesorado monopolice la docencia, y es necesario comunicarles tanto al alumnado como al profesorado, que la docencia es una inversión en beneficio mutuo. La realización de este tipo de proyectos favorece notablemente a los alumnos ya que desarrollan la motivación de aprendizaje o puesta en práctica de las enseñanzas recibidas, pero lo que sin duda es motivador para ellos es el reconocimiento social al trabajo realizado. Esto se ve reflejado en la Estrategia Europea 2020 a nivel universitario que habla de reforzar la cooperación entre la Universidad, Investigación y Empresa

Insights into the room temperature magnetism of ZnO/Co3O4 mixtures

The origin of room temperature (RT) ferromagneticlike behavior in ZnO-based diluted magnetic semiconductors is still an unclear topic. The present work concentrates on the appearance of RT magnetic moments in just mixed ZnO/Co3O4 mixtures without thermal treatment. In this study, it is shown that the magnetism seems to be related to surface reduction of the Co3O4 nanoparticles, in which, an antiferromagnetic Co3O4 nanoparticle (core) is surrounded by a CoO-like shell. This singular superficial magnetism has also been found in other mixtures with semiconductors such as TiO2 and insulators such as Al2O3

Origin and provenance of igneous clasts from late Palaeozoic conglomerate formations (Del Ratón and El Planchón) in the Andean Precordillera of San Juan, Argentina

Late Palaeozoic conglomerate formations (Del Ratón and El Planchón) from the Andean Precordillera (Argentina) were studied to unravel their age, composition and provenance. The conglomerates from the Del Ratón Formation are formed by igneous clasts of acid, intermediate and basic compositions (volcanic and plutonic). Laser Ablation (ICP-MS) zircon U-Pb study has yielded an age of 348±2 Ma (late Tournaisian) for the crystallization of a granitic clast, interpreted as a maximum deposition age for the Del Ratón Formation. Geochemistry of these clasts (high LILE/HFSE and La/Yb ratios, negative Nb-Ta anomalies) suggests a calc-alkaline batholithic source, probably located along the Andean Frontal Cordillera currently to the west, where similar calc-alkaline igneous rocks have been described. The El Planchón Formation overlies the Del Ratón Formation and, in the studied conglomerates, there are only igneous clasts of mafic composition (volcanic/subvolcanic). These mafic clasts have a very similar petrography and geochemistry to the Late Ordovician mafic igneous rocks of the Western Precordillera (low LILE/HFSE and La/Yb ratios, no negative Nb-Ta anomalies). Therefore we suggest that the El Planchón conglomerate clasts were probably delivered mainly from northern sources within the Precordillera terrane. This change in clast provenance is tentatively related to a shift in mountain uplift from the Frontal Cordillera (in the west) to the Precordillera (in the east) after the early Visean.Las formaciones conglomeráticas del Paleozoico superior (Del Ratón y El Planchón) de la Precordillera Andina (Argentina) fueron es­tudiadas con el fin de determinar su edad, composición y procedencia. Los conglomerados de la Formación Del Ratón están constituidos por clastos de rocas ígneas (volcánicas y plutónicas) ácidas, intermedias y básicas. Un estudio en circones con espectrometría de masas con plasma acoplado por inducción con ablación láser (LA-ICP-MS) proporciona una edad de 348±2 Ma (Tournaisiense superior) para la cristalización de un clasto granítico, que interpretamos como la máxima edad del depósito de la Formación Del Ratón. La geoquímica de los clastos (altas relaciones LILE/HFSE y La/Yb, anomalías negativas de Nb-Ta) sugiere que probablemente derivan de batolitos calcoal­calinos descritos en algunos sectores de la Cordillera Frontal Andina localizada actualmente al oeste. La Formación El Planchón se super­pone a la Formación Del Ratón y los clastos estudiados en los conglomerados de esta formación son únicamente de rocas ígneas básicas (subvolcánicas/volcánicas). Estos clastos tienen una petrografía y geoquímica similar a las rocas ígneas máficas del Ordovícico Superior de la Precordillera Occidental (bajas relaciones LILE/HFSE y La/Yb, ausencia de anomalías negativas en Nb-Ta). Por ello nosotros suge­rimos que los clastos de los conglomerados de la Formación El Planchón proceden de materiales localizados al norte dentro de la propia Precordillera. Este cambio en la procedencia de los clastos es tentativamente relacionado con una transferencia de la deformación desde la Cordillera Frontal (al oeste) a la Precordillera (al este), provocando el levantamiento de la Precordillera a partir del Viseense inferior

Emergence of small-scale magnetic loops through the quiet solar atmosphere

We investigate the emergence of magnetic flux in the quiet Sun at very small spatial scales, focusing on the magnetic connection between the photosphere and chromosphere. The observational data consist of spectropolarimetric measurements and filtergrams taken with the Hinode satellite and the Dutch Open Telescope. We find that a significant fraction of the magnetic flux present in internetwork regions appears in the form of Omega-shaped loops. The emergence rate is 0.02 loops per hour and arcsec^{-2}, which brings 1.1 x 10^12 Mx s^{-1} arcsec^{-2} of new flux to the solar surface. Initially, the loops are observed as small patches of linear polarization above a granular cell. Shortly afterwards, two footpoints of opposite polarity become visible in circular polarization within or at the edges of the granule and start to move toward the adjacent intergranular space. The orientation of the footpoints does not seem to obey Hale's polarity rules. The loops are continuously buffeted by convective motions, but they always retain a high degree of coherence. Interestingly, 23% of the loops that emerge in the photosphere reach the chromosphere (16 cases out of 69). They are first detected in Fe I 630 nm magnetograms and 5 minutes later in Mg I b 517.3 nm magnetograms. After about 8 minutes, some of them are also observed in Ca II H line-core images, where the footpoints produce small brightness enhancements.Comment: Accepted for publication in Ap

Two-dimensional solar spectropolarimetry with the KIS/IAA Visible Imaging Polarimeter

Spectropolarimetry at high spatial and spectral resolution is a basic tool to characterize the magnetic properties of the solar atmosphere. We introduce the KIS/IAA Visible Imaging Polarimeter (VIP), a new post-focus instrument that upgrades the TESOS spectrometer at the German VTT into a full vector polarimeter. VIP is a collaboration between the KIS and the IAA. We describe the optical setup of VIP, the data acquisition procedure, and the calibration of the spectropolarimetric measurements. We show examples of data taken between 2005 and 2008 to illustrate the potential of the instrument. VIP is capable of measuring the four Stokes profiles of spectral lines in the range from 420 to 700 nm with a spatial resolution better than 0.5". Lines can be sampled at 40 wavelength positions in 60 s, achieving a noise level of about 2 x 10E-3 with exposure times of 300 ms and pixel sizes of 0.17" x 0.17" (2 x 2 binning). The polarization modulation is stable over periods of a few days, ensuring high polarimetric accuracy. The excellent spectral resolution of TESOS allows the use of sophisticated data analysis techniques such as Stokes inversions. One of the first scientific results of VIP presented here is that the ribbon-like magnetic structures of the network are associated with a distinct pattern of net circular polarization away from disk center. VIP performs spectropolarimetric measurements of solar magnetic fields at a spatial resolution that is only slightly worse than that of the Hinode spectropolarimeter, while providing a 2D field field of view and the possibility to observe up to four spectral regions sequentially with high cadence. VIP can be used as a stand-alone instrument or in combination with other spectropolarimeters and imaging systems of the VTT for extended wavelength coverage.Comment: 10 pages, 8 figures, accepted by Astronomy and Astrophysics v2: figures updated with improved qualit

Stokes imaging polarimetry using image restoration at the Swedish 1-m Solar Telescope

Aims: We aim to achieve high spatial resolution as well as high polarimetric sensitivity, using an earth-based 1m-class solar telescope, for the study of magnetic fine structure on the Sun. Methods: We use a setup with 3 high-speed, low-noise cameras to construct datasets with interleaved polarimetric states, particularly suitable for Multi-Object Multi-Frame Blind Deconvolution image restorations. We discuss the polarimetric calibration routine as well as various potential sources of error in the results. Results: We obtained near diffraction limited images, with a noise level of approximately 10^(-3) I(cont). We confirm that dark-cores have a weaker magnetic field and at a lower inclination angle with respect to the solar surface than the edges of the penumbral filament. We show that the magnetic field strength in faculae-striations is significantly lower than in other nearby parts of the faculae.Comment: Accepted for publication in Astronomy & Astrophysics, 12 pages, 11 figure

First report of Solanum sisymbriifolium and S. americanum as Natural weed hosts of Tomato chlorosis virus (Genus Crinivirus) in South America.

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