Resumo Tradicionalmente, estruturas submetidas ao vento são avaliadas através de análises estáticas com carregamentos equivalentes, onde a influência da resposta flutuante é levada em conta por meio do fator de rajada. Essa metodologia é aplicável a estruturas suficientemente rígidas para não apresentarem resposta dinâmica ponderável [ ]. Estruturas mais flexíveis, em particular aquelas fracamente amortecidas, podem apresentar importante resposta ressonante e devem ter suas propriedades dinâmicas consideradas na análise. O objetivo deste artigo é apresentar uma metodologia para a análise dinâmica de estruturas submetidas ao vento considerando a não-linearidade geométrica, a vibração causada pela energia cinética das rajadas de vento e o amortecimento aerodinâmico devido ao movimento relativo entre a estrutura e o vento. A metodologia proposta é aplicada à estrutura de uma chaminé de concreto com 180 metros de altura, sendo os resultados comparados com os obtidos através das recomendações da norma ABNT NBR 6123:1988 [ ] para a análise dinâmica de estruturas.

Abstract Usually, the analysis of structures under wind loading is performed using an equivalent static analysis, where the influence of floating response is taken into account by the gust factor. This methodology can be used in case of rigid structures for not presenting a considerable dynamic response. More flexible structures, in particular those lightly damped, may show an important resonant response and their dynamic properties must be considered in the analysis. The aim of this paper is to present a methodology for dynamic analysis of structures under wind loading considering the geometric nonlinearity, the vibration caused by the kinetic energy of wind gusts and the aerodynamic damping due to the relative movement between this structure and the wind. The formulation proposed is applied to a 180-meter-high concrete chimney and the results were compared with those obtained through the recommendation given in the standard ABNT NBR 6123:1988 [2] for the dynamic structural analysis.

Introduction: The identification of stages of dietary change and the factors affecting food choices can direct more effective nutritional intervention against coronary heart disease progression. Objective: Identify the stages of change of eating behavior and its relation with nutritional status, food consumption and previous cardiovascular events in patients who underwent coronary angioplasty. Methods: A cross-sectional study with 200 hospitalized patients from a specialized cardiology hospital, after elective coronary angioplasty. They were applied an algorithm that identifies the provision of change of eating habits for a healthier pattern. Variables measured were stages of change of eating behavior, nutritional status, food consumption and cardiovascular events (previous myocardial infarction or angioplasty). It was realized comparison of averages by analysis of variance or Student´s test and Chi-square test for qualitative variables. Value of significance was taken at 5%. Results: The patients were classified in the following stages: 36% maintenance, 26% preparation, 17% precontemplation, 12% action and 9% contemplation. It was observed higher cardiovascular events in maintenance/action group (p = 0.04), higher consumption of calories (p = 0.04), meat/eggs (p = 0.01) and sweets (p = 0.03) in preparation stage, comparing to maintenance group, and no association between nutritional status and stages of change (p = 0.13), although 62% of the individuals in maintenance stage were overweight. Conclusions: This work contributed to identifying the stages of change and conditions that favor changes in eating pattern. Even patients that classified themselves into the maintenance stage need to adjust their eating habits in order to reach a healthy weight.

Introducción: La identificación de las etapas de cambio en la dieta y los factores que afectan la elección de alimentos puede dirigir una intervención nutricional más eficaz contra la progresión de la enfermedad coronaria. Objetivos: Identificar las etapas de cambio de la conducta alimentaria y su relación con el estado nutricional, consumo de alimentos y los eventos cardiovasculares anteriores en pacientes sometidos a angioplastia coronaria. Métodos: Estudio transversal con 200 pacientes de un hospital especializado en cardiología, después de angioplastia coronaria electiva. Se aplicaron un algoritmo que identifica la disposición del cambio de hábitos de alimentación para un patrón mas saludable. Las variables medidas fueron las etapas de cambio de la conducta alimentaria, estado nutricional, consumo de alimentos y eventos cardiovasculares (infarto de miocardio o angioplastia previos). Resultados: los pacientes fueron clasificados en las siguientes etapas: 36% en mantenimiento, 26% en preparación, 17% en precontemplación, 12% en acción y 9% en contemplación. Se observaron mas eventos cardiovasculares en mantenimiento/ acción (p = 0,04), mayor consumo de calorías (p = 0,04), carne y huevos (p = 0,01) y dulces (p = 0,03) en la etapa de preparación, en comparación con el de mantenimiento, y ninguna asociación entre el estado nutricional y las etapas de cambio (p = 0,13), aunque el 62% de los individuos en la etapa de mantenimiento estaban con sobrepeso. Conclusiones: Este trabajo contribuyó por la identificación de las etapas de cambio y las condiciones que favorecen los cambios en el patrón de alimentación. Mismo los pacientes que se clasificaron a la fase de mantenimiento hay la necesidad de ajustar sus hábitos alimenticios con el fin de lograr un peso saludable.