民办教育是一项朝阳事业——兼谈民办教育在广州开发区的实践

《中华人民共和国民办教育促进法》施行不到两年，已极大地推动了民办教育的健康发展。但是由于历史、观念和体制等因素，不少人对民办教育的重要性和历史地位还认识不足，依然存在着这样或那样的偏见。笔者结合当前广州开发区推进民办教育的实践经验，初步探讨大力发展民办教育的积极意义。     

An overview of cricket ball swing

The aerodynamic properties of a cricket ball have intrigued cricket players and spectators for years, arguably since the advent of the game itself. The main interest is in the fact that the ball can follow a curved flight path that may not always be under the control of the bowler. The basic aerodynamic principles responsible for the nonlinear flight or ‘swing’ of a cricket ball were identified decades ago and many papers have been published on the subject. Over the last 25 years or so, several empirical investigations have also been conducted on cricket ball swing, which revealed the amount of attainable swing and identified the parameters that affect it. Those findings are reviewed here with emphasis on phenomena such as late swing and the effects of humidity on swing. The relatively new concept of ‘reverse swing’, how it can be achieved in practice, and the role in it of ‘ball tampering’, are also discussed in detail. In particular, the ability of some bowlers to effectively swing an old ball in the conventional, reverse and the newly termed ‘contrast’ swing mode is addressed. A discussion of the ‘white” cricket ball used in the 1999 and 2003 World Cup tournaments, which supposedly possesses different swing properties compared to a conventional red ball, is also included. This is a current overview of cricket ball swing rather than a detailed review of all research work performed on the topic. The emphasis is on presenting scientific explanations for the various aerodynamic phenomena that affect cricket ball swing on a cricket ground.     

法国、意大利大量文物被盗

据法国著名保险集团公司ARGOS提供的材料，文物走私成了仅次于毒品走私的全球第二大非法行业。大约每一小时就会在法国或意大利发生一起文物盗窃案。