ON TWO AFFINE CONNECTIONS

The study of geometric objects is perhaps one of the principal aimsof modern differential geometry.According to Veblen a geometricobject in a space R_n with the coordinates x~1, ....,x~n is defined by a setof components A~1,....,A~r such that these components undergo a trans-formation when the coordinates x~1,....,x~n are subjected to a generalpoint transformation.Obviously this definition is purely analytical.In     

新疆的湖泊

中国最干、最热、最冷的地方都在新疆维吾尔自治区境内：中国最长的内陆河、最低的洼地、最大的沙漠也在新疆?在新疆不仅可以观赏到驰名中外的冰川雪峰、雅丹地貌、戈壁荒漠、风蚀蘑菇、洞穴、石林、草原森林以及沙漠中的海市蜃楼、飞沙鸣唱等独特的自然景观,同时还可以感受许多各具特色、风光如画的湖泊所带给您的美的震撼。     

纳木错流域扎当冰川径流对气温和降水形态变化的响应

报道西藏纳木错湖南岸念青唐古拉山脉北坡扎当冰川2007/2008年的径流年际大变化并分析其成因. 与2007年夏半年相比, 2008年同期降水量增加了17.9%, 流域径流量却减少了33.3%, 由此得出冰川消融量减少了53.8%. 利用通常的度日模型分析发现, 大气正积温的变化只能解释约一半的冰川消融量年际差, 说明该冰川对气温变化异常敏感. 能量平衡分析显示, 冰川表面反照率的改变造成了冰川消融量的年际重大差异. 而反照率的改变主要是由降水形态的差异造成的. 统计得出, 2007年夏半年冰川末端以降雨为主, 降雨量占降水总量的71.5%; 相反, 2008年以降雪为主, 降雨量仅占30.7%. 说明在对某些冰川进行气候变化的敏感性分析或径流预测时, 降水形态是需要单独考虑的一个因素.     

巨石之谜：深溪大石浪

浙江安吉当地有这么一个传说：相传女娲娘娘用五色石共补天36处,到了安吉报福这最后一处的时候,她发现所带的五色石已经全部用完,已经补了35处天的女娲已是精疲力竭,只能向伏羲求助。伏羲随即动身前往安吉,助女娲一臂之力,他一边赶路一边沿途收集适合炼石的石头。     

多元化：做自己最能做的事

“多元化”自出现在我们视野中便热潮不退,它似乎成了业界“冰川时期”各企业的救命稻草,抓住了它就意味着抓住了新的经济增长点。于是PC巨子不仅要做手机还要进军房地产;家电领军加入PC大战已是人所共知,杀入保险业再爆冷门。于是,人们不禁怀疑,各企业如此“不务正业”究竟意欲何在?多元化战略真的能对他们起到火箭加速器的作用?多元化对这些企业来说究竟是康庄大道还是崎岖小路?采访中,上海科技投资公司总经理陈伟丰先生谈到了自己的一些想法。     

The possible pivotal role of the eastward dust transport from Central Asia in the global temperature decrease

It is generally considered that the occurrence of glacial-interglacial gyrations can be explained with the Milankovitch theory. However, the solutions of some problems in the theory are currently not derived yet. After researching the eastward dust transport from Central Asia, we have found that there is a positive feedback mechanism between the eastward dust transport and the global temperature decrease. This magnifies the effect of solar radiation change in the high-latitude Hemisphere, and results in area of the Northern the occurrence of the global glacial epoch. The positive feedback mechanism starts with the reduction of solar radiation in the high-latitude area of the Northern Hemisphere. Subsequently, the global temperature decreases and global glacial epoch occurs, in which the pivotal fac- tor is the eastward dust transport from Central Asia. With the theory of the positive feedback mechanism, some problems in the Milankovitch theory can be solved well.     

"发烧"的地球

冰川在消失,极地冰架在崩塌,海平面在上升,永久冻结带已不再亘古不化……地球变暖究竟会给人类的生存环境带来什么样的影响呢?阅读本文你也许能找到一些答案。