899 resultados para 290000 Engineering and Technology


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The purpose of this study was to evaluate the tissue composition and carcass muscularity of 32 legs of Ile de France lambs fed with diets containing sunflower seeds and vitamin E, with mean body weight of 15 kg, lodged in individual pens at 15 kg and slaughtered at 32 kg of body weight. The treatments influenced (P<0,05) leg weight, femur length and muscle: bone ratio, being the highest values (2,13 kg, 16,19 cm and 7,38, respectively) in lambs that received diet without sunflower seeds and vitamin E. The other variables were not affected (P>0,05) by the treatments. The interaction of the sunflower and vitamin E was positive for bone total weights and intramuscular fat.

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This publication, compiled by Gilberto C. Gallopín, Regional Adviser in Environmental Policy for Latin America and the Caribbean, contains the results of the deliberations of the Latin American and Caribbean Regional Workshop on Science and Technology for Sustainable Development. The purpose of the Workshop was to discuss the practical, theoretical and organizational challenges that the quest for sustainable development poses to science and technology (S&T). The increase in complexity and connectivity characteristic of our times results in that the components of the problems are now much less separable than before, and emphasizes the need to approach the problems of development and the environment not only as complex issues in themselves, but also as inseparable and mutually determined. This represents an exceptional challenge to science and technology, particularly to the analytical approaches compartmentalized into disciplines, which represents the bulk of activities and priorities of current S&T systems in both north and south. The Workshop attempted to articulate a Latin American and Caribbean vision towards the search of more effective ways of generating and applying Science and Technology to the problems and opportunities of the region.

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The aim of the present study was to evaluate the effect of disinfection and accelerated ageing on the dimensional stability and detail reproduction of a facial silicone with different types of nanoparticle. A total of 60 specimens were fabricated with Silastic MDX 4-4210 silicone and they were divided into three groups: colourless and pigmented with nanoparticles (make-up powder and ceramic powder). Half of the specimens of each group were disinfected with Efferdent tablets and half with neutral soap for 60 days. Afterwards, all specimens were subjected to accelerated ageing. Both dimensional stability and detail reproduction tests were performed after specimen fabrication (initial period), after chemical disinfection, and after accelerated ageing periods (252, 504 and 1008 hours). The dimensional stability test was conducted using AutoCAD software, while detail reproduction was analysed using a stereoscope magnifying glass. Dimensional stability values were statistically evaluated by analysis of variance (ANOVA) followed by Tukey's test (p < 0.01). Detail reproduction results were compared using a score. Chemical disinfection and also accelerated ageing affected the dimensional stability of the facial silicone with statistically significant results. The silicone's detail reproduction was not affected by these two factors regardless of nanoparticle type, disinfection and accelerated ageing. © 2012 Informa UK, Ltd.

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Includes bibliography

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Includes bibliography

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The purpose of this study was to investigate the effect of thermal cycling and disinfection on the microhardness of acrylic resins denture base. Four different brands of acrylic resins were evaluated: Onda Cryl, QC 20, Classico and Lucitone. Each brand of acrylic resin was divided into four groups (n = 7) according to the disinfection method (microwave, Efferdent, 4% chlorhexidine and 1% hypochlorite). Samples were disinfected during 60 days. Before and after disinfection, samples were thermal cycled between 5-55 °C with 30-s dwell times for 1000 cycles. The microhardness was measured using a microhardener, at baseline (B), after first thermal cycling (T1), after disinfection (D) and after second thermal cycling (T2). The microhardness values of all groups reduced over time. QC-20 acrylic resin exhibited the lowest microhardness values. At B and T1 periods, the acrylic resins exhibited statistically greater microhardness values when compared to D and T2 periods. It can be concluded that the microhardness values of the acrylic resins denture base were affected by the thermal cycling and disinfection procedures. However, all microhardness values obtained herein are within acceptable clinical limits for the acrylic resins. © 2013 Informa UK Ltd.

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Presenta la organizacion de los trabajos y el resumen de los debates de la reunion del CEGAN, realizada en Montevideo entre el 23 y el 24 de enero de 1984 en la cual se trataron la evaluacion de la aplicacion del Programa de Accion de Viena sobre ciencia y tecnologia para el desarrollo en America Latina, las propuestas de medidas y acciones futuras y las recomendaciones a los organos internacionales y regionales.