Assessment of seismic performance of adobe structures in Pakistan and Portugal

Adobe buildings exist in different parts of the world. The construction of these buildings can be carried out economically, using locally available materials and skills that do not require use of modern machinery. Therefore, adobe buildings provide an economic housing option. The construction of adobe structures is carried out based on traditional construction practices which vary from region to region. This paper presents the results of a study which was conducted to study the construction practices of adobe buildings in Pakistan and Portugal in the context of their seismic vulnerability. The adobe buildings in both these countries were found to be subjected to seismic hazard levels which, although is low in some regions, may cause significant damages. Lack of essential elements or details for the adequate seismic performance was found in the adobe buildings in both regions

Estudo de retenção de carotenoides totais em híbridos de mandioca cozida.

O consumo culinário das raízes de mandioca é bastante generalizado em todo o mundo, sendo que a forma de processamento mais utilizada na América Latina e África é o cozimento. As raízes de mandioca ainda podem ser integradas a pratos mais complexos. O melhoramento e a seleção de matérias primas de origem vegetal com altos conteúdos de micronutrientes vêm sendo realizada nos países em desenvolvimento com a finalidade de minimizar carências nutricionais

El ser humano y la biodiversidad en el ecosistema : validación de una experiencia de aula

En la enseñanza de las ciencias el concepto de biodiversidad emerge en diferentes campos (genética, evolución. . . ) y en ocasiones no se le otorga la importancia que posee en cada uno de ellos. El estudio de la biodiversidad demanda una concepción compleja del medio, ya que las sociedades humanas son importantes agentes de cambio de la naturaleza e influyen en su diversidad. Además la enseñanza debe concebirse desde una perspectiva de comprensión, reflexión y evaluación de nuestra propia práctica. Por ello en este trabajo se realiza la validación de una serie de actividades, que fueron previamente llevadas al aula, dirigidas al estudio de la diversidad en el ecosistema y la influencia de las sociedades humanas en el cambio del mismo

Classical and quantum wormholes in a flat Λ\Lambda-decaying cosmology

We study the classical and quantum wormholes for a flat {\it Euclidean} Friedmann-Robertson-Walker metric with a perfect fluid including an ordinary matter source plus a source playing the role of dark energy (decaying cosmological term). It is shown that classical wormholes exist for this model and the quantum version of such wormholes are consistent with the Hawking-Page conjecture for quantum wormholes as solutions of the Wheeler-DeWitt equation.Comment: 8 pages, 4 figures, accepted for publication in IJT

Geometrical Constraints on the Cosmological Constant

The cosmological constant problem is examined under the assumption that the extrinsic curvature of the space-time contributes to the vacuum. A compensation mechanism based on a variable cosmological term is proposed. Under a suitable hypothesis on the behavior of the extrinsic curvature, we find that an initially large $\Lambda(t)$ rolls down rapidly to zero during the early stages of the universe. Using perturbation analysis, it is shown that such vacuum behaves essentially as a spin-2 field which is independent of the metric.Comment: [email protected], 17 pages, Latex, 2 figures obtained by reques

Discrete and finite Genral Relativity

We develop the General Theory of Relativity in a formalism with extended causality that describes physical interaction through discrete, transversal and localized pointlike fields. The homogeneous field equations are then solved for a finite, singularity-free, point-like field that we associate to a ``classical graviton". The standard Einstein's continuous formalism is retrieved by means of an averaging process, and its continuous solutions are determined by the chosen imposed symetry. The Schwarzschild metric is obtained by the imposition of spherical symmetry on the averaged field.Comment: Modified conform the version to appear in Classical and Quantum Gravit