2,806 research outputs found
The Weak Gravity Conjecture in three dimensions
We study weakly coupled theories in , their associated charged
BTZ solutions, and their charged spectra. We find that modular invariance of
the holographic dual two-dimensional CFT and compactness of the gauge group
together imply the existence of charged operators with conformal dimension
significantly below the black hole threshold. We regard this as a form of the
Weak Gravity Conjecture (WGC) in three dimensions. We also explore the
constraints posed by modular invariance on a particular discrete
symmetry which arises in our discussion. In this case, modular invariance does
not guarantee the existence of light -charged states. We also
highlight the differences between our discussion and the usual heuristic
arguments for the WGC based on black hole remnants.Comment: 44 page
Post-depositional tectonic modifications of VMS deposits in Iberia and its economic significance
The original stratigraphic relationships and structure of VMS deposits are commonly obscured by deformation. This can also affect their economic significance, as shown by several Iberian Pyrite Belt (IPB, SW Iberia) examples. The contrasting rheologic properties of the different lithologies present in an orebody (massive sulphide, feeder stockwork, alteration envelope, volcanic and sedimentary rocks) playa major role in determining its overall behaviour. Variscan thin-skinned tectonics led to stacking of the massive pyrite and stockwork bodies in duplex structures, resulting in local thickening and increased tonnage of minable mineralization. Furthermore, differential mechanical behaviour of the different sulphide minerals localised the detachments along relatively ductile sulphide-rich bands. The result was a geochemical and mineralogical reorganisation of most deposits, which now consist of barren, massive pyrite horses, bounded by base metal-rich ductile shear zones. Metal redistribution was enhanced by mobilisation of the base metal sulphides from the initially impoverished massive pyrite, through pressuresolution processes, to tensional fissures within the already ductile shear zones. In NW Iberia, VMS deposits were also strongly overprinted by the Variscan deformation during emplacement of the Cabo Ortegal and Órdenes allochthonous nappe complexes, but no stacking of the orebodies was produced. Original contacts were transposed, and the orebodies, their feeder zones and the country rock acquired pronounced laminar geometry. In lower-grade rocks (greenschist facies, Cabo Ortegal Complex), solution transfer mechanisms are common in pyrite, which remains in the brittle domain, while chalcopyrite shows ductile behaviour. In higher-grade rocks (amphibolite facies, Órdenes Complex), metamorphic recrystallisation overprints earlier deformation textures. The contrasting behaviour of the IPB and NW Iberian deposits is explained by key factors that affect their final geometry, composition and economics, such as pre-deformation structure, size and mineralogical composition of the orebody and associated lithologies, temperature, crustal level, deviatoric stress and availability of a fluid phase during deformation and the style and rate of deformation
Evolución longitudinal del cabalgamiento de Peña Sobia (Asturias)
Las modernas interpretaciones tectónicas de la Cordillera Cantábrica, llevan a considerar que la Rodilla Astúrica está formada por una serie de escamas y en ocasiones verdaderos mantos vergentes hacia el centro de ésta, deformados por una serie de pliegues claramente visibles al oriente de la Cuenca Minera Central, donde llevan una dirección E-W. El objeto de esta nota es estudiar cómo una de las escamas, la de Peña Sobia, evoluciona hacia el N a una zona de pliegues de dirección general N-S
Agotamiento del crédito y dificultades de transporte (Dos problemas de las relaciones comerciales republicanas entre particulares durante la guerra civil española 1936-1939)
La influència de les rutes a la història mundial
Article sobre la influència de les rutes de la humanitat en la història mundial des dels orìgens fins l'actualitat
Villanueva Alonso, María Luisa (dir./ed.), La Méditerranée et la culture du dialogue (Lieux de rencontré et de mémoire des Européens) – El Mediterráneo y la cultura del diálogo (Lugares de encuentro y de memoria de los europeos) – El Mediterrani i la cultura del diàleg (Punts de trovada i de memòria dels europeus), Bruselas, P.I.E. Peter Lang, 2008, 339 pp.
MARIMON, Antoni; SERRA, Sebastià (dirs.), Diccionari de Partits Polítics de les Illes Balears (1900-2008), Palma, Lleonard Muntaner Editor, 2012, 460 pp.
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