110 research outputs found
Nariai, Bertotti-Robinson and anti-Nariai solutions in higher dimensions
We find all the higher dimensional solutions of the Einstein-Maxwell theory
that are the topological product of two manifolds of constant curvature. These
solutions include the higher dimensional Nariai, Bertotti-Robinson and
anti-Nariai solutions, and the anti-de Sitter Bertotti-Robinson solutions with
toroidal and hyperbolic topology (Plebanski-Hacyan solutions). We give explicit
results for any dimension D>3. These solutions are generated from the
appropriate extremal limits of the higher dimensional near-extreme black holes
in a de Sitter, and anti-de Sitter backgrounds. Thus, we also find the mass and
the charge parameters of the higher dimensional extreme black holes as a
function of the radius of the degenerate horizon.Comment: 10 pages, 11 figures, RevTeX4. References added. Published versio
The paleoenvironmental and thermal histories of the Permian Irati formation shale in the paraná basin, Brazil: An integrated approach based on mineralogical and organic imprints
ABSTRACT: Mineralogical assemblages and organofacies are important sources of information to recover the paleoenvironmental and thermal histories of shale deposits. In this study, a detailed qualitative and quantitative characterization of the Permian Irati Formation (Assistência Member) shale is based on mineralogical (XRD and SEM-EDS) and organic components (TOC, Rock-Eval pyrolysis, organofacies, TAI, fluorescence and vitrinite reflectance measurements) and provides integrated data about sediment provenance, depositional environment, diagenesis, and thermal history, while supporting interpretations on the Paraná Basin (PB), Brazil, paleogeography and its correlation to the southwest Gondwana. The results revealed a prevailing type I/II kerogen, with type III kerogen being also present but mainly confined along the paleoshoreline of the PB. The dominance of fluorescent amorphous organic matter (AOM) combined with framboidal pyrite suggests microbial activity in an anoxic-dysoxic neritic-marine paleoenvironment. Additionally, common to abundant well-preserved phytoclasts, as well as the occurrence of Botryococcus braunii, indicates freshwater influx in a brackish marine depositional setting. Immature to early-oil window thermal maturities prevail across the PB, according to the organic maturation indicators. The combined analysis between the organic matter evolution with clay mineralogy, such as the occurrence of interstratified clays (e.g., I/S) and its positive correlation with depth suggest that burial diagenesis reached the transition to early catagenesis on the north, southeast, and south of the basin, attributing a shale oil potential for the Irati Formation on a regional scale. Local scale imprints of the Early Cretaceous Paraná-Etendeka Large Igneous Province (LIP), and its thermal effect in the Irati Formation shale components, are recorded as clay authigenesis (e.g., smectite webby texture and clay coating development), crystallization of minerals by low to high-grade of thermal alteration (e.g., corrensite, talc, lizardite and diopside), and by local scale gas-window maturities. Such thermal alteration, identified in the proximity to intruded sills and dykes, led to a heterogeneous organic maturation pattern with implications on shale gas and shale oil potential of the Irati Formation shale, demonstrating that these subjects in the Paraná Basin should be assessed locally.info:eu-repo/semantics/publishedVersio
Canonical quantization of so-called non-Lagrangian systems
We present an approach to the canonical quantization of systems with
equations of motion that are historically called non-Lagrangian equations. Our
viewpoint of this problem is the following: despite the fact that a set of
differential equations cannot be directly identified with a set of
Euler-Lagrange equations, one can reformulate such a set in an equivalent
first-order form which can always be treated as the Euler-Lagrange equations of
a certain action. We construct such an action explicitly. It turns out that in
the general case the hamiltonization and canonical quantization of such an
action are non-trivial problems, since the theory involves time-dependent
constraints. We adopt the general approach of hamiltonization and canonical
quantization for such theories (Gitman, Tyutin, 1990) to the case under
consideration. There exists an ambiguity (not reduced to a total time
derivative) in associating a Lagrange function with a given set of equations.
We present a complete description of this ambiguity. The proposed scheme is
applied to the quantization of a general quadratic theory. In addition, we
consider the quantization of a damped oscillator and of a radiating point-like
charge.Comment: 13 page
Eletrorrecuperação de cobre e oxidação de cianeto de efluentes cianídricos diluídos gerados por unidade de galvanoplastia
Reactivation of latent bovine herpesvirus type 5 in cattle with polioencephalomalacia induced by ammonium sulphate
Características de solos construídos após mineração de carvão relacionadas ao processo de construção e à composição do material utilizado
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