Supersymmetry of the 2+1 black holes

The supersymmetry properties of the asymptotically anti-de Sitter black holes of Einstein theory in 2+1 dimensions are investigated. It is shown that (i) the zero mass black hole has two exact super- symmetries; (ii) extreme $lM=|J|$ black holes with $M \not= 0$ have only one; and (iii) generic black holes do not have any. It is also argued that the zero mass hole is the ground state of (1,1)-adS supergravity with periodic (``Ramond") boundary conditions on the spinor fields.Comment: 9 pages LaTeX file, ULB-PMIF-93/0

Non-existence of static multi-black-hole solutions in 2+1 dimensions

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Selfdual solutions of (2+1) Einstein gravity with a negative cosmological constant

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Emplacement processes and cooling history of layered cyclic unit II-7 from the Lovozero alkaline massif (Kola Peninsula, Russia)

The Lovozero alkaline massif (Kola Peninsula, Russia) is composed of three major units. The central unit (80% of the volume) comprises numerous well developed layers composed, from bottom to roof, of an urtite-juvite-foyaite-lujavrite continuous lithological sequence (ijolite-foid-bearing alkali feldspar syenite in IUGS nomenclature). The mode of emplacement of the massif and the mechanism of formation of the layering are still under debate. Petrological, mineralogical (two stages of crystallisation) and structural evidence from the detailed analysis of one of these layers (unit II-7) is interpreted in terms of both mechanical (magmatic to sub-solidus, non-coaxial deformation) and thermal differentiation operating on a crystal-laden (alkali feldspar, high T nepheline, aegirine-augite) material of foyaitic composition. Textural and mineralogical data suggest that a sheet of foiditic magma intruded into solidified earlier units of the Lovozero layered sequence and acquired a sill-like structure on cooling. © 2005 Elsevier B.V. All rights reserved.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Magmatic garnet-bearing mafic xenoliths (Puy Beaunit, French Massif Central): P-T path from crystallisation to exhumation

Mafic xenoliths, sometimes interlayered with magmatic peridotites, are abundant in the scoria cones of Puy Beaunit in the French Massif Central. These are mainly layered gabbronorites with some norites, pyroxenites and anorthosites; they probably derive from a Permian differentiated deep layered intrusion. Crystallisation conditions were estimated at about 1000°C and 1 GPa. The rocks underwent sub-solidus re-equilibration at about 770°C and 1 GPa (isobaric cooling) in the lowermost crust. Two distinct symplectitic textures (pyroxene-plagioclase-spinel intergrowths) have been observed; they result from the destabilization of magmatic garnet (750-800°C, 0.55-0.8 GPa) and amphibole (990°C, < 0.3 GPa). Melting of amphibole and destabilisation of orthopyroxene occurs during xenolith ascent. Garnet was destabilised either during tectonic uplift of the lower crust during Early Cenozoic or at the first step of xenolith ascent to the surface. Whole-rock REE concentrations show that some xenoliths are typically plagioclase-rich cumulates, others are pyroxene-rich cumulates. Few mafic xenoliths display HREE enrichment, (La/Yb)N ratios lower than 1, presumably indicating garnet cumulation. Major-element composition of the fine-grained plagioclase-orthopyroxene-spinel symplectites is indeed close to that of a pyrope-almandine garnet with significant grossular content. The presence of this magmatic garnet argues for a hydrated calc-alkaline high-alumina basaltic magma in which the various mafic cumulates crystallised at depth. © 2005 E. Schweizerbart'sche Verlagsbuchhandlung.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Trace element distribution in silicate phases from the cumulate mafic xenoliths of Puy Beaunit (French Massif Central): A LA-ICP-MS study

EAE03-02105. EUG, Nice, France.info:eu-repo/semantics/publishe

A differentiated ultramafic- mafic deep magma chamber beneath the French Massif Central: Evidence from the xenoliths of Puy Beaunit

Colloque en l'honneur de J.-C. Duscheneinfo:eu-repo/semantics/nonPublishe

Simulation assessment of a closed-loop controller designed by machine learning techniques

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The role of computer technology in radiosurgery.

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