攀枝花市为什么不能成为物流中心城市

周边环境的区域经济特点和攀枝花市地理位置、本市生产的出境物流量、地理约束对交通状况的影响等因素综合作用限制了攀枝花成为区域物流中心，攀枝花市无法成为物流中心城市。从提高物流水平的角度来看，攀枝花市应当将重点放在提高物流效率上，其主导思想应该是减少政府干预、建立完善的市场体系。     

重视英语教育的意义

目前我国政府正不遗余力地推动以英语为主的外语教育、教学与研究,视英语为发展全面教育、提高国民整体素质的一个重要环节。英文教学是我国现代化的一个重要环节,是改革开放的一把钥匙,是中国走向世界的一个保证,是最终实现中华民族伟大复兴的重要保障之一。     

广告是不是科学传播的死敌

广告是伴随着商品生产和商品交换而出现的,是商品经济发展的必然产物。广告在我国的命运经历过重大变迁。20世纪30～40年代的上海滩曾经是广告遍地。建国后,广告曾被认为是"摆噱头、吹牛皮,资本主义生意经",很难在媒体上出现。改革开放之初,电视广告的出现甚至被认为是     

中国武术散手进入奥运会的困境分析

从散手比赛对运动员意外伤害及人们对散手运动的理解,经济的发展及宣传包装对散手运动推广的重要意义,散手运动所需要的硬、软件设施以及散手运动员自身的素质要求等方面找出散手未进入奥运会的原因并进行了分析．     

P-M hybrid dysgenesis does not mobilize other transposable element families in D. melanogaster

Mobilization of the P family of transposable elements in Drosophila melanogaster occurs in the hybrid progeny of males from an element-bearing strain (P strain) and females from an element-free strain (M strain). We tested whether the same crosses could mobilize other families of transposable elements. A mating scheme was used in which a set of X chromosomes was kept for 20 generations in either the active condition (known as hybrid dysgenesis) or the inactive condition (nondysgenic). Examination of 19 families of transposable elements by in situ hybridization indicated that only the P family was measurably mobilized under dysgenic conditions. Thus, P-M hybrid dysgenesis does not increase the transpositional activity of other families of transposable elements in D. melanogaster. We discuss possible explanations for several published reports to the contrary.     

Evolutionary genomics: codon volatility does not detect selection

Plotkin et al. introduce a method to detect selection that is based on an index called codon volatility and that uses only the sequence of a single genome, claiming that this method is applicable to a large range of sequenced organisms. Volatility for a given codon is the ratio of non-synonymous codons to all sense codons accessible by one point mutation. The significance of each gene's volatility is assessed by comparison with a simulated distribution of 10(6) synonymous versions of each gene, with synonymous codons drawn randomly from average genome frequencies. Here we re-examine their method and data and find that codon volatility does not detect selection, and that, even if it did, the genomes of Mycobacterium tuberculosis and Plasmodium falciparum, as well as those of most sequenced organisms, do not meet the assumptions necessary for application of their method.