Ab initio calculation of the dynamical properties of PPP and PPV

In this work, we have calculated the vibrational modes and frequencies of the crystalline PPP (in both the Pbam and Pnnm symmetries) and PPV (in the P21/c symmetry). Our results are in good agreement with the available experimental data. Also, we have calculated the temperature dependence of their specific heats at constant volume, and of their vibrational entropies. Based on our results, at high temperatures, the PPP is more stable in the Pnnm structure than in the Pbam one.Comment: 5 pages, 7 figures, accepted for publication in Braz. J. Phys., special number, Proceedings of BWSP-12, 12th Brazilian Workshop on Semiconductor Physic

Em busca de sustentabilidade agrícola: tópicos em educação ambiental, agroecologia, agroecossistemas e biodiversidade

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Forgotten Foods: The Impact Of Western Development On Eating Habits Among Women In Dehradun, India

This paper investigates the impact that Western development has had on eating habits among women living in the greater Dehradun area of India over the last century. Research was undertaken while working at Bija Vidyapeeth, an organic farm and educational center operated by the Indian-based Non-Governmental Organization, Navdanya. Primary data was collected by interviewing twelve women from four families, spanning three generations and ranging in age from 106 to 20. Two of the four families live in the urban center of Dehradun, while the other two families practice farming outside the city limits. Interviews revealed a generational change in eating habits among families living in the city of Dehradun, while agrarian families were more resistant to broad incorporation of Western influences into their diets and lifestyles. Data was analyzed within the framework of the Basic Human Needs development strategy, and the structural violence that has resulted from the imposition of this development model by Western powers