Closed Expressions for Lie Algebra Invariants and Finite Transformations

A simple procedure to obtain complete, closed expressions for Lie algebra invariants is presented. The invariants are ultimately polynomials in the group parameters. The construction of finite group elements require the use of projectors, whose coefficients are invariant polynomials. The detailed general forms of these projectors are given. Closed expressions for finite Lorentz transformations, both homogeneous and inhomogeneous, as well as for Galilei transformations, are found as examples.Comment: 34 pages, ps file, no figure

A lower bound to the spectral threshold in curved tubes

We consider the Laplacian in curved tubes of arbitrary cross-section rotating together with the Frenet frame along curves in Euclidean spaces of arbitrary dimension, subject to Dirichlet boundary conditions on the cylindrical surface and Neumann conditions at the ends of the tube. We prove that the spectral threshold of the Laplacian is estimated from below by the lowest eigenvalue of the Dirichlet Laplacian in a torus determined by the geometry of the tube.Comment: LaTeX, 13 pages; to appear in R. Soc. Lond. Proc. Ser. A Math. Phys. Eng. Sc

Contribuição do uso da terra e do manejo do solo para a recarga de aquíferos.

Neste texto é apresentada uma visão da pesquisa quanto à importância do conhecimento edafoambiental e do monitoramento do efeito de tecnologias e práticas de manejo e de conservação dos recursos naturais - solo, água e biodiversidade - de ocorrência nas denominadas zonas de recarga de aquíferos. O objetivo principal é a construção de cenários futuros, capazes de predizer a eficácia das tecnologias e das práticas em uso e formular propostas para a recarga dos sistemas hídricos brasileiros. Para isso, são necessários estudos envolvendo as relações hídricas (pluviométrica, subterrânea e superficial) e edafoambientais (solo, clima, uso potencial e atual) que permitam a compreensão da complexidade envolvida na recarga dos aquíferos, tendo como componente integrador o processo de infiltração vertical da água pluvial.bitstream/CNPS-2010/14888/1/comtec32-2005-recarga-aquiferos.pd

Solos: além de tudo, sequestro de carbono.

bitstream/item/26842/1/Solos-alm-de-tudo-sequestro-de-carbono-Portal-Dia-de-Campo.pd

Sistema plantio direto: conceitos, adoção e fatores limitantes

bitstream/CNPS-2010/14900/1/comtec31-2005-plantio-direto.pd

Raman scattering through surfaces having biaxial symmetry

Magnetic Raman scattering in two-leg spin ladder materials and the relationship between the anisotropic exchange integrals are analyzed by P. J. Freitas and R. R. P. Singh in Phys. Rev. B, {\bf 62}, 14113 (2000). The angular dependence of the two-magnon scattering is shown to provide information for the magnetic anisotropy in the Sr_14Cu_24O_41 and La_6Ca_8Cu_24O_41 compounds. We point out that the experimental results of polarized Raman measurements at arbitrary angles with respect to the crystal axes have to be corrected for the light ellipticity induced inside the optically anisotropic crystals. We refer quantitatively to the case of Sr_14Cu_24O_41 and discuss potential implications for spectroscopic studies in other materials with strong anisotropy.Comment: To be published as a Comment in Phys. Rev.

Serious Games in Cultural Heritage

Although the widespread use of gaming for leisure purposes has been well documented, the use of games to support cultural heritage purposes, such as historical teaching and learning, or for enhancing museum visits, has been less well considered. The state-of-the-art in serious game technology is identical to that of the state-of-the-art in entertainment games technology. As a result the field of serious heritage games concerns itself with recent advances in computer games, real-time computer graphics, virtual and augmented reality and artificial intelligence. On the other hand, the main strengths of serious gaming applications may be generalised as being in the areas of communication, visual expression of information, collaboration mechanisms, interactivity and entertainment. In this report, we will focus on the state-of-the-art with respect to the theories, methods and technologies used in serious heritage games. We provide an overview of existing literature of relevance to the domain, discuss the strengths and weaknesses of the described methods and point out unsolved problems and challenges. In addition, several case studies illustrating the application of methods and technologies used in cultural heritage are presented

A pesquisa técnico-científica sobre o gênero Eucalyptus na Embrapa Florestas: um estudo cienciométrico.

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