Variation of the first Hilbert coefficients of parameters with a common integral closure

A problem posed by Wolmer V. Vasconcelos on the variation of the first Hilbert coefficients of parameter ideals with a common integral closure in a local ring is studied. Affirmative answers are given and counterexamples are explored as well

Numerical solution of linear models in economics: The SP-DG model revisited

In general, complex and large dimensional models are needed to solve real economic problems. Due to these characteristics, there is either no analytical solution for them or they are not attainable. As a result, solutions can be only obtained through numerical methods. Thus, the growing importance of computers in Economics is not surprising. This paper focuses on an implementation of the SP-DG model, using Matlab,developed by the students as part of the Computational Economics course. We also discuss some of our teaching/learning experience within the course, given for the first time in the FEP Doctoral Programme in Economics.SP-DG Model, Output, Inflation, Numerical Simulation, Teaching of Economics

Obtenção e aproveitamento da farinha de pupunha.

bitstream/item/28078/1/com.tec.145.pd

Aproveitamento tecnológico da farinha de fruta-pão.

bitstream/item/27696/1/Com.tec.187.pd

The role of damped Alfven waves on magnetospheric accretion models of young stars

We examine the role of Alfven wave damping in heating the plasma in the magnetic funnels of magnetospheric accretion models of young stars. We study four different damping mechanisms of the Alfven waves: nonlinear, turbulent, viscous-resistive and collisional. Two different possible origins for the Alfven waves are discussed: 1) Alfven waves generated at the surface of the star by the shock produced by the infalling matter; and 2) Alfven waves generated locally in the funnel by the Kelvin-Helmholtz instability. We find that, in general, the damping lengths are smaller than the tube length. Since thermal conduction in the tube is not efficient, Alfven waves generated only at the star's surface cannot heat the tube to the temperatures necessary to fit the observations. Only for very low frequency Alfven waves ~10^{-5} the ion cyclotron frequency, is the viscous-resistive damping length greater than the tube length. In this case, the Alfven waves produced at the surface of the star are able to heat the whole tube. Otherwise, local production of Alfven waves is required to explain the observations. The turbulence level is calculated for different frequencies for optically thin and thick media. We find that turbulent velocities varies greatly for different damping mechanisms, reaching \~100 km s^{-1} for the collisional damping of small frequency waves.Comment: 29 pages, 12 figures, to appear in The Astrophysical Journa

Characterization of South American exotic maize (Zea mays L.) populations with opaque phenotype.

Eleven exotic populations of opaque maize from Brazil. Bolívia and Chile, were characterized. Kernels density, lysine and tryptophan contents, total zeins and non-zeins, zein individual fractions, and soluble sugars were analyzed. Although these populations bear soft endosperm, their zein prolifes by gel electrophoresis, the nutritional quality of their proteins as well as the densities of their grains do not follow the patterns present in other opaque maize genotypes. We concluded that these exotic populations are not included in any class of endosperm mutant described so far

Plantas medicinais utilizadas na medicina etnoveterinária praticada na ilha do Marajó.

bitstream/item/63225/1/Oriental-Doc380.pd