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

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.

Prevention of advancing degradation and recovery of degraded lands.

This chapter presents an overview on the main technological contributions of Embrapa and partners to halt land degradation, accelerated erosive processes, desertification, sanding, salinization, and to restore degraded lands, as established in target 15.3 (United Nations, 2018): By 2030, combat desertification, restore degraded land and soil, including land affected by desertification, drought and floods, and strive to achieve a land degradation-neutral world.bitstream/item/204882/1/Prevention-of-advancing-degradation-and-recovery-of-degraded-lands-2019.pd

Personalised trails and learner profiling within e-learning environments

This deliverable focuses on personalisation and personalised trails. We begin by introducing and defining the concepts of personalisation and personalised trails. Personalisation requires that a user profile be stored, and so we assess currently available standard profile schemas and discuss the requirements for a profile to support personalised learning. We then review techniques for providing personalisation and some systems that implement these techniques, and discuss some of the issues around evaluating personalisation systems. We look especially at the use of learning and cognitive styles to support personalised learning, and also consider personalisation in the field of mobile learning, which has a slightly different take on the subject, and in commercially available systems, where personalisation support is found to currently be only at quite a low level. We conclude with a summary of the lessons to be learned from our review of personalisation and personalised trails

Testing the SUSY-QCD Yukawa coupling in a combined LHC/ILC analysis

In order to establish supersymmetry (SUSY) at future colliders, the identity of gauge couplings and the corresponding Yukawa couplings between gauginos, sfermions and fermions needs to be verified. Here a first phenomenological study for determining the Yukawa coupling of the SUSY-QCD sector is presented, using a method which combines information from LHC and ILC.Comment: 5pp, slightly expanded version of contributions to the Proc. of the Linear Collider Workshop (LCWS 06), Bangalore, India, 9-13 March 2006, and the Proc. of the 14th International Conference on Supersymmetry and the Unification of Fundamental Interactions (SUSY 06), Irvine, California, USA, 12-17 June 200

Relação entre o intervalo de partos e o custo total de produção de leite por vaca no rebanho.

O intervalo de partos foi a variavel de maior impacto nos custos de producao de vacas da raca holandesa de primeira e segunda lactacoes, seguida da producao total de leite. A idade ao primeiro parto e o valor genetico relacionaram-se apenas com o custo de producao de vacas holandesas de primeira lactacao. No caso de vacas mesticas (HZ) de primeira e segunda lactacao apenas o intervalo de partos e a producao total de leite relacionaram-se com o custo total.Resumo expandido