Resumen Definimos un nuevo analizador para Gramáticas de Adjunción de Árboles (TAGs, Tree Adjoining Grammars) que es una extensión del analizador ascendente guiado por la esquina izquierda para Gramáticas Incontextuales (CFGs, Context Free Grammars). La complejidad temporal teórica del nuevo analizador permanece en la cota del análisis de TAGs, siendo ésta de O(n6) en el peor de los casos, dond...

We present an exact analytical solution of the Einstein equations with cosmological constant in a spatially flat Robertson-Walker metric. This is interpreted as an isotropic Lemaitre-type version of the cosmological Friedmann model. Implications in the recent discovered cosmic acceleration of the universe and in the theory of an inflationary model of the universe are in view. Some properties of...

The algebra of conserved observables of the SO(4, 1) gauge-invariant theory of the Dirac fermions in the external field of the KaluzaKlein monopole is investigated. It is shown that the Dirac conserved operators have physical parts associated with Pauli operators that are also conserved in the sense of the Klein-Gordon theory. In this way one gets simpler methods of analyzing the properties of ...

The genus Anthemis L., assigned by Bremer (1994) to the tribe Anthemideae (subtribe Anthemidinae) of the Asteraceae, comprises ca. 210 species. The Anthemidinae consist of the genus Anthemis with provisional addition of the monotypic genus NanantheaDC (Bremer, 1994). Anthemis wiedemanniana Fisch. & C.A. Mey. (section Cota) is an endemic species distributed in the Mediterranean, the Middle and t...

Este trabalho objetivou avaliar o padrão atual de distribuição Caatinga densa, identificando onde estão seus maiores fragmentos, através procedimentos cartográficos e estatísticos no município Caicó-RN. A partir NDVI, gerou-se mapeamento da cobertura vegetal e, em seguida, delimitou-se três intervalos cotas altimétricas possibilitando-se traçar um perfil gradual. Os fragmentos densa foram subme...

BACKGROUND Laccases are multi-copper oxidases that catalyze the one electron oxidation of a broad range of compounds. Laccase substrates include substituted phenols, arylamines and aromatic thiols. Such compounds are activated by the enzyme to the corresponding radicals. Owing to their broad substrate range laccases are considered to be versatile biocatalysts which are capable of oxidizing natu...