7,384 research outputs found

    Los yacimientos del cuarzo-apatito (fosforita) en el Macizo Hespérico español: el caso de Aldea Moret-Zarza la Mayor (Cáceres)

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    [Resumen] Los filones de Q-Ap se hallan en zona orgánica intracontinental de reactivación de zócalos antiguos. Corresponden a yacimientos plutonogénicos relacionados con granitoides peralumínicos. Poseen estructuras y texturas de relleno, siendo su morfologia filoniana según se deduce de los planos de la mina. El tipo espectral (o tipoquímico) del apatito es característico de yacimientos hidroternales (caracter hipotermal) y su composición es la de fluorapatito. No existe un fondo geoquímico elevado en P, sino que es la presencia de mineralizadores como el F que concentra el P en un modelo halogénico.[Abstract] Since 1961, date of establishment of the firm, the investigations made gave as a result 35,000,000 Tm of reserves, being exploited 120,000 tpa. In this paper a description of benefitiation process and fina1 products is made, appearing that they are mainly for exporte In addition, considerations concerning the significance of magnesium in animal nutrition and its app1ication for it are made. Finally, difficulties and proposed solutions are quote

    Overconvergent Eichler-Shimura isomorphisms for quaternionic modular forms over Q

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    In this work we construct overconvergent Eichler-Shimura isomorphisms over Shimura curves over Q. More precisely, for a prime p > 3 and a wide open disk U in the weight space, we construct a Hecke-Galois-equivariant morphism from the space of families of overconvergent modular symbols over U to the space of families of overconvergent modular forms over U . In addition, for all but finitely many weights λ ∈ U , this morphism provides a description of the finite slope part of the space of overconvergent modular symbols of weight λ in terms of the finite slope part of the space of overconvergent modular forms of weight λ + 2. Moreover, for classical weights these overconvergent isomorphisms are compatible with the classical Eichler-Shimura isomorphism.Postprint (author's final draft

    Census of HII regions in NGC 6754 derived with MUSE: Constraints on the metal mixing scale

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    We present a study of the HII regions in the galaxy NGC 6754 from a two pointing mosaic comprising 197,637 individual spectra, using Integral Field Spectrocopy (IFS) recently acquired with the MUSE instrument during its Science Verification program. The data cover the entire galaxy out to ~2 effective radii (re ), sampling its morphological structures with unprecedented spatial resolution for a wide-field IFU. A complete census of the H ii regions limited by the atmospheric seeing conditions was derived, comprising 396 individual ionized sources. This is one of the largest and most complete catalogue of H ii regions with spectroscopic information in a single galaxy. We use this catalogue to derive the radial abundance gradient in this SBb galaxy, finding a negative gradient with a slope consistent with the characteristic value for disk galaxies recently reported. The large number of H ii regions allow us to estimate the typical mixing scale-length (rmix ~0.4 re ), which sets strong constraints on the proposed mechanisms for metal mixing in disk galaxies, like radial movements associated with bars and spiral arms, when comparing with simulations. We found evidence for an azimuthal variation of the oxygen abundance, that may be related with the radial migration. These results illustrate the unique capabilities of MUSE for the study of the enrichment mechanisms in Local Universe galaxies.Comment: 13 pages, 7 Figurs, accepted for publishing in A&

    Effective electronic response of a system of metallic cylinders

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    The electronic response of a composite consisting of aligned metallic cylinders in vacuum is investigated, on the basis of photonic band structure calculations. The effective long-wavelength dielectric response function is computed, as a function of the filling fraction. A spectral representation of the effective response is considered, and the surface mode strengths and positions are analyzed. The range of validity of a Maxwell-Garnett-like approach is discussed, and the impact of our results on absorption spectra and electron energy-loss phenomena is addressed.Comment: 15 pages, 6 figures, to appear in Phys. Rev.

    Analogies between the crossing number and the tangle crossing number

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    Tanglegrams are special graphs that consist of a pair of rooted binary trees with the same number of leaves, and a perfect matching between the two leaf-sets. These objects are of use in phylogenetics and are represented with straightline drawings where the leaves of the two plane binary trees are on two parallel lines and only the matching edges can cross. The tangle crossing number of a tanglegram is the minimum crossing number over all such drawings and is related to biologically relevant quantities, such as the number of times a parasite switched hosts. Our main results for tanglegrams which parallel known theorems for crossing numbers are as follows. The removal of a single matching edge in a tanglegram with nn leaves decreases the tangle crossing number by at most n3n-3, and this is sharp. Additionally, if γ(n)\gamma(n) is the maximum tangle crossing number of a tanglegram with nn leaves, we prove 12(n2)(1o(1))γ(n)<12(n2)\frac{1}{2}\binom{n}{2}(1-o(1))\le\gamma(n)<\frac{1}{2}\binom{n}{2}. Further, we provide an algorithm for computing non-trivial lower bounds on the tangle crossing number in O(n4)O(n^4) time. This lower bound may be tight, even for tanglegrams with tangle crossing number Θ(n2)\Theta(n^2).Comment: 13 pages, 6 figure

    Evolución petrológico geoquímica de los granitoides hercínicos del NO gallego

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    [Resumen] Se estudia el conjunto de rocas graníticas hercínicas del sector noroeste de Galicia, desde el punto de vista petrológico y geoquímico. Por características tect6nicas y mineral6gicas se han distinguido cuatro grupos de granitoides: Granotáides precoces, granitoides inhomogneos,/granitos de dos micas pre-fase 3, y granitos postcinemáticos. Todos los grupos, a excepci6n de los granitoides precoces, tienen una tendencia geoquímica más ácida y evolucionada que la media total de los granitoides gallegos. Los contenidos en Li,Rb,Ba,Sr, demuestran igualmente un alto grado de diferenciación. L1 y Rb por un lado, y Ba y Sr. por otro, se comportan de manera análoga en todos los grupos.[Abstract] This paper deals with the petrological and geochémical aspects of Hercynian granitic rocks in the northwestern part of Galicia. Based on minerological and structural criteria four granitoid groups are distinguished: Early-Hercynian granitoids, " inhomogeneus granitoids " , an'older group of two-micas granite (prior to the third Hercynian deformation) and postcinematic granites. Geochemically al1 the granitic rocks, with the exception of the EarlyHercynian granitoids, are more acid than the average value of all Galician granitoids. Also the abundances of Li, Rb, Ba, and Sr demonstrate a high degree of differentiation. The element pairs Li-Rb and Ba-Sr, tend to behave similarly in the granitoid groups

    The Calar Alto Legacy Integral Field Area Survey: extended and remastered data release

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    This paper describes the extended data release of the Calar Alto Legacy Integral Field Area (CALIFA) survey (eDR). It comprises science-grade quality data for 895 galaxies obtained with the PMAS/PPak instrument at the 3.5 m telescope at the Calar Alto Observatory along the last 12 years, using the V500 setup (3700-7500{\AA}, 6{\AA}/FWHM) and the CALIFA observing strategy. It includes galaxies of any morphological type, star-formation stage, a wide range of stellar masses (\sim107^7 1012^{12} Msun ), at an average redshift of \sim0.015 (90\% within 0.005<<z<<0.05). Primarily selected based on the projected size and apparent magnitude, we demonstrate that it can be volume corrected resulting in a statistically limited but representative sample of the population of galaxies in the nearby Universe. All the data were homogeneous re-reduced, introducing a set of modifications to the previous reduction. The most relevant is the development and implementation of a new cube-reconstruction algorithm that provides with an (almost) seeing-limited spatial resolution (FWHM PSF \sim1.0").To illustrate the usability and quality of the data, we extracted two aperture spectra for each galaxy (central 1.5" and fully integrated), and analyze them using pyFIT3D. We obtain a set of observational and physical properties of both the stellar populations and the ionized gas, that have been compared for the two apertures, exploring their distributions as a function of the stellar masses and morphologies of the galaxies, comparing with recent results in the literature. DATA RELEASE: http://ifs.astroscu. unam.mx/CALIFA_WEB/public_html/Comment: 30 pages, 26 figures, accepted for publishing in the MNRA
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