O ensino tipo “e-learning”: alguns comentários

The scientific and technological development, has brought the possibility of people having access to a large volume of information, especially via the Internet. However, this information has to be filtered, due to danger of assimilating wrong and unreliable information. The so-called teaching type "e-learning" adopted by some schools, seems to have solved these problems. This paper focuses on some problems associated with the teaching system of "e-learning" and the difficulty to adapt it to certain areas of knowledge. The advantages of the courses in "bi-learning" are presented as well as some of the drawbacks associated with this type of education.

Homotheties and topology of tangent sphere bundles

We prove a Theorem on homotheties between two given tangent sphere bundles SrM of a Riemannian manifold (M,g) of dim ≥ 3, assuming different variable radius functions r and weighted Sasaki metrics induced by the conformal class of g. New examples are shown of manifolds with constant positive or with constant negative scalar curvature which are not Einstein. Recalling results on the associated almost complex structure I^G and symplectic structure ω^G on the manifold TM , generalizing the well-known structure of Sasaki by admitting weights and connections with torsion, we compute the Chern and the Stiefel-Whitney characteristic classes of the manifolds TM and SrM.