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Systematic investigations of conformational effects of the hydroxyl group on carbon or hydrogen chemical shifts of different types of alcohols reveal that, besides stereoelectronic effects, hyperconjugation with lone pairs may have a strong influence. In view of the growing use of chemical shifts in probing the structure of biologic molecules, we employed DFT/GIAO/NBO calculations at the B3LYP level for conformers obtained from partial optimization of structures resulting from 30°variations of the COCOXOH (XAO, N) dihedral angles to verify if nitrogen responded in a fashion similar to oxygen. Although the hybridization and geometry of hydroxyl and amine groups are distinct, the lone pair on nitrogen reveals hyperconjugation with suitably positioned orbitals on alkyl groups.

In this paper, the evolution of the energy use by human society is discussed, relating the energy, environmental and economic crisis, which appear to be closely linked. With the widespread use of fossil fuels since the industrial revolution, a major environmental problem was generated: the climate changes. The economic consequences of climate changes are discussed in Stern

We display a simplified geometrical model which aims to facilitate the understanding of current environmental problems: the sustainable complex triangular cell model. At the present stage of the human society, the cell will be represented as a scalene triangle, symbolizing distorted relationships among Energy, Economy and Ecology. By applying the concept of sustainability, it becomes possible to propose a transformation of the irregular triangle into an equilateral one, indicating a more symmetrical relationship among the 3E and, finally, the building up of a hexagonal regular community formed by these equilateral triangles. As a limiting case, one can admit a geometrical collapse of that hexagon in the case study here discussed: the recent discovering of an isolated Indian tribe at Amazon.