When economically still underdeveloped , china has accomplished a historic transition in population reproduction pattern from one featuring high birth rate , low death rate and high growth rate to one featuring low birth rate , low death rate and low growth rate in a relatively short period of time , a change that took decades or even up to a hundred years for developed countries to realize in the past 中国在经济不发达的情况下，用较短的时间实现了人口再生产类型从高出生、低死亡、高增长到低出生、低死亡、低增长的历史性转变，走完了一些发达国家数十年乃至上百年才走完的路。
In a controlled lab experiment , psychologist rich walker of winston - salem state university found that the reasons are two - fold : people tend to emphasize positive emotions and mitigate negative ones when telling a story , since memory ' s natural bias is to keep tabs on the good stuff and gradually lose the emotional intensity of a bad event ; and the process of storytelling can affect how one feels about what happened even up to a week later 在一项受控制的实验室实验中，温斯顿塞勒姆州立大学州立大学的心理学家瑞奇.沃克发现原因有两点：在讲一段事情的时候，人们往往会强调正面的情绪，而减轻负面的情绪，这是由于记忆存在自然的偏见，它会把好东西记住，把坏事件的情绪程度逐渐地丢失；故事讲述的过程可以对即便是已经发生了一周以后，人们的感受产生影响。
There is more and more evidence that hemodynamic factors play an important role in the development of the arterial atherogenesis , but even up to now , the specific role of the hemodynamic factors is not well understood yet , therefore further research work of revealing the biomechanical mechanism of atherosclerosis is helpful and necessary to learn its pathology and occurrence , which is very important in biofluid dynamics and is closely related to the development of the biofluid dynamics in theory and numerical simulation , the investigation of coronary circulation rules of human cardiovascular system and the further study of occurrence mechanism of cardiovascular diseases , so is of great significance in both scientific research work and realistic application 越来越多的研究证据表明，血流动力学因素在动脉粥样硬化的发生和发展过程中起着关键的作用。但时至今日血流动力学因素确切的作用还需要进一步了解，因此更深入地研究动脉粥样硬化的生物力学机理对于掌握动脉粥样硬化的病理和发病规律有着巨大的研究价值。近年来，随着人们生活水平的不断提高和生活结构的逐步改变，心血管病的发病率也在不断增加，并已经成为危害人类生命健康最为严重的疾病之一，其患病率和死亡率居各类疾病之首，因而成为发达国家和发展中国家的头号杀手。
