Causal Propagators for Algebraic Gauges

Applying the principle of analytic extension for generalized functions we derive causal propagators for algebraic non-covariant gauges. The so generated manifestly causal gluon propagator in the light-cone gauge is used to evaluate two one-loop Feynman integrals which appear in the computation of the three-gluon vertex correction. The result is in agreement with that obtained through the usual prescriptions.Comment: LaTex, 09 pages, no figure

A Laplace transform approach to the quantum harmonic oscillator

The one-dimensional quantum harmonic oscillator problem is examined via the Laplace transform method. The stationary states are determined by requiring definite parity and good behaviour of the eigenfunction at the origin and at infinity

Hamilton-Jacobi formalism for Linearized Gravity

In this work we study the theory of linearized gravity via the Hamilton-Jacobi formalism. We make a brief review of this theory and its Lagrangian description, as well as a review of the Hamilton-Jacobi approach for singular systems. Then we apply this formalism to analyze the constraint structure of the linearized gravity in instant and front-form dynamics.Comment: To be published in Classical and Quantum Gravit

On Graph Refutation for Relational Inclusions

We introduce a graphical refutation calculus for relational inclusions: it reduces establishing a relational inclusion to establishing that a graph constructed from it has empty extension. This sound and complete calculus is conceptually simpler and easier to use than the usual ones.Comment: In Proceedings LSFA 2011, arXiv:1203.542

Bianchi Type I Cosmology in N=2, D=5 Supergravity

The dynamics and evolution of Bianchi type I space-times is considered in the framework of the four-dimensional truncation of a reduced theory obtained from the N=2,D=5 supergravity. The general solution of the gravitational field equations can be represented in an exact parametric form. All solutions have a singular behavior at the initial/final moment, except when the space-time geometry reduces to the isotropic flat case. Generically the obtained cosmological models describe an anisotropic, expanding or collapsing, singular Universe with a non-inflationary evolution for all times.Comment: revised version to appear in PR

Avaliação econômica de diferentes sistemas de preparo do solo na cultura do algodoeiro arbóreo Estado da Paraíba - 1977/79.

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Streptomyces axinellae sp. nov., isolated from the Mediterranean sponge Axinella polypoides (Porifera)

An actinomycete strain, isolated from the marine sponge Axinella polypoides collected from Banyuls-sur-Mer, France, was characterized using a polyphasic approach. Based on its chemotaxonomic and morphological characteristics, strain Pol001(T) belongs to the genus Streptomyces. The strain is characterized by ll-diaminopimelic acid in the cell wall, menaquinones MK-9(H(4), H(6), H(8)) and a DNA G+C content of 71.0 mol%. It forms a separate phyletic line based on phylogenetic analyses of the nearly complete 16S rRNA gene sequence. Strain Pol001(T) could be differentiated from other closely related Streptomyces species with validly published names by phenotypic and genotypic analysis. DNA-DNA hybridization between strain Pol001(T) and closely related reference strains further confirmed that strain Pol001(T) represents a novel taxon of the genus Streptomyces. Therefore, it is proposed that strain Pol001(T) represents a novel species in the genus Streptomyces, Streptomyces axinellae sp. nov.; the type strain is Pol001(T) (=DSM 41948(T) =CIP 109838(T))

Análise espacial da integridade das áreas de preservação permanente em projeto de assentamento rural no município de São Francisco do Pará-PA.

A vegetação ripária apresenta uma funcionalidade ambiental de grande relevância, na medida em que atua como filtro de retenção de sedimentos e elementos químicos, proporcionando entre outros aspectos, a proteção e a manutenção dos canais fluviais e suas nascentes. Embora essa formação seja protegida por lei, a mesma vem sofrendo crescentes intervenções, o que exige o desenvolvimento de estudos de avaliação e monitoramento dos seus processos de antropização. Assim, a partir do emprego de produtos e técnicas de sensoriamento remoto e geoprocessamento, este trabalho tem por objetivo avaliar espacialmente a situação das Áreas de Preservação Permanente no projeto de assentamento ?Luiz Lopes Sobrinho?, Nordeste Paraense. Para isso, foram realizadas análises em escala de detalhe, a partir de imagem SPOT-5, de 2008. A partir da análise dos preceitos da legislação florestal vigente, verificou-se que 90% das áreas em questão se encontram com cobertura florestal preservada. Os resultados alcançados apresentam potencialidade para fornecer subsídios para averbação das áreas com restrição legal ao uso da terra junto aos órgãos competentes.PIBIC-2011