Is It Demographic Dividend or Trap for India and China?

The relation between economic growth and population growth is a widely debated topic in economics.The discussioncircles around three main views about demography;(i) Population Neutralism,(ii) Demographic Dividends,and (iii)Demographic Traps.This paper provides a quantitative definition of the demographic trap based on the theoreticaldemographic distribution curve.We then compare the results of the world’s two most populous countries,China and India.The results show that India may fall into a demographic trap while China will not and,hence these two countries exhibittwo distinctly opposite demographic characteristics.Extending the results to include examination of a set of rich and poorcountries,we conclude that there is no evidence of a demographic trap in the U.S.and Canada,while it is highly possiblethat Algeria and Angola will get caught in one.

Lewis肺癌小鼠血管内皮生长因子的时间节律性表达

目的:检测日间和夜间Lewis肺癌小鼠血清中内血管内皮生长因子(VEGF)水平和肺癌组织中VEGF蛋白表达的差别,探讨肿瘤血管生成的昼夜节律。方法:选择C57BL小鼠30只,制备Lewis肺癌小鼠模型后随机分为日间组(D组)和夜间组(N组),在光照-黑暗条件下饲养建立统一同步化日夜节律。随着成瘤过程,应用ElISA方法测定两组小鼠模型第0、3、5、7天血清中VEGF浓度水平;成瘤后第9天处死小鼠,应用Westeon-blot法检测瘤体中VEGF蛋白的表达,并分别进行相关分析。结果:随着成瘤过程,D组小鼠血清中VEGF浓度均显著高于N组(P<0.05);D组小鼠瘤体组织中VEGF蛋白表达灰度值(8.87±1.20)均明显高于N组(6.43±1.35),有统计学意义(P<0.05)。结论:Lewis小鼠休息期(白天)血清中VEGF浓度及瘤体中VEGF蛋白表达水平均明显高于活动期(夜间),存在着明显的日夜差异,说明肺癌组织的血管生成可能具有一定日夜节律。