GM(1,1)模型参数估计的新方法及假设检验

ＧＭ（１，１）模型参数估计的新方法及假设检验唐五湘（北京机械工业学院工商管理分院，１０００８５）ＡＮｅＷＭｅｔｈｏｄｏｆＥｓｔｉｍａｔｉｏｎｏｆｔｈｅＧＭ（１，１）ＭｏｄｅｌＰａｒａｍｅｔｅｒｓａｎｄＨｙｐｏｔｈｅｓｉｓＴｅｓｔｉｎｇＴａｎｇＷｕｘｉ...     

Redefining tumour suppressor genes: exceptions to the two-hit hypothesis

Knudsons two-hit model of tumour suppressor genes supposes that two mutations are required to cause a tumour, one occurring in each of the two alleles of the gene. Many such cancer genes exhibiting biallelic disruption and truncating point mutations have been identified, revealing the success of the model. Despite changes in our concept of cancer genes, two inactivating point mutations are still considered the hallmark of tumour suppressor genes. Recently, however, more and more reports describe candidate tumour suppressors that do not conform to this standard definition, including haploinsufficient genes requiring inactivation of only one allele, and genes inactivated not by mutation but rather epigenetic hypermethylation. This review describes some of these exceptions and proposes a revised tumour suppressor gene definition to facilitate the identification of this new generation of tumour suppressor loci.Received 21 January 2003; received after revision 26 March 2003; accepted 1 April 2003     

戏剧中"假定"的艺术魅力

戏剧艺术家为了把生活中的场面提炼到动人心魄和趣意盎然的程度,并着力表达他对生活的理解和评价,就必须致力于解决生活的无限性和戏剧的有限性的矛盾。“假定”是意外、巧合、偶然、震惊等手段的概括,是艺术家们解决这个矛盾并乐意运用的方法。纵观颈剧这一艺术形式有发生发展史,不仅是剧情,也包括剧场、演员和观众都是一种特殊的假定”。可认为没有“假定”就没有戏剧,一部成功的戏剧,就是艺术家对生活的一段巧妙的“假定”。     

The insect antenna is not a molecular sieve

Summary The deposition rate of 2 tritiated odorants onto insect antennae of different sizes and shapes is linearly proportional to the product of odorant concentration times the antennal surface area. This result challenges an assumption in a commonly accepted hypothesis that sensillar shape affects odorant deposition and that a single odorant molecule can initiate an action potential in a receptor cell. Consequently the 1-molecule-1-spike hypothesis bears reinvestigation.     

Strategic bias and professional affiliations of macroeconomic forecasters

This paper investigates strategic motives of macroeconomic forecasters and the effect of their professional affiliations. The ‘wishful expectations hypothesis’ suggests that a forecaster predicts what his employer wishes. The ‘publicity hypothesis’ argues that forecasters are evaluated by both accuracy and ability to generate publicity, and that forecasters in industries that emphasize publicity most will make most extreme and least accurate predictions. The ‘signaling hypothesis’ asserts that an extreme forecast signals confidence in own ability, because incompetent forecasters would mimic others to avoid public notice. Empirical evidence from a 26‐year panel of annual GDP forecasts is con‐sistent with the publicity hypothesis. This indicates that conventional tests of rationality are biased toward rejecting the rational expectations hypothesis. Copyright ? 2008 John Wiley & Sons, Ltd.     

区间删失情形下基于熵的指数性的检验

考虑了当观测存在区间删失情形下指数性的检验问题.记随机样本为{Xi}ni=1,观测值为Yi=a如Xi<a,Yi=b如Xi>b,否则Yi=Xi. 其中0≤a<b≤∞为两个常数.我们给出了检验{Xi}的指数性的一个有效的方法,并得到了检验的相合性.模拟结果表明检验与已有的完全观测情形下的检验(参见Ebrahimi Habibul lah, Soofi. Journal of the Royal Statistical Society. Series B. 1992, Vol.54 p739～p748)有类似的极限性质.     

论不用平面假设推导材料力学应力公式

传统材料力学教材里,使用平面假设推导应力公式时,采取由表及里的方法去推测截面内部应力分布规律,显得繁琐,实属滞留在材料力学教材中已被科技发展逾越了的陈旧内容。本文认为可直接应用光测法的结论,把应力分布规律视作已知,直接应用于应力公式的推导中,从而可使应力公式的推导简明扼要,更符合理论与实验相结合的要求。     

基于TIN分块的数字影象自适应几何纠正方法

数字影象的高精度几何纠正一般采用分块的方法,在进行分块纠正时,必须解决影象分割、分块影象公共边的连续性问题,本文采用 TIN 网格分割影象,从理论上推导了数字影象纠正的数学模型并证明了边界连续性问题,设计了分块进行数字影象自适应纠正的技术路线。     

论马克思、恩格斯"跨越"设想的当代价值(二)

马克思、恩格斯“跨越”设想包含着他们的历史代价思想,体现了他们在资本主义世界历史即将步入社会主义、共产主义世界历史的时代背景下,期望不遭受或少遭受资本主义制度所带来的灾难、以较小的历史代价获得巨大历史进步的共产主义人道追求。他们在如何实现代价最小化上进行了苦苦探索,尽管俄国公社事实上解体了,通过了资本主义制度的卡夫丁峡谷,但他们的代价思想,他们以最小的代价实现最大的历史进步的追求值得我们今天深思和借鉴。我们应该在改革开放的实践中确立积极的代价意识,以期以最小的代价实现最大的历史进步。