A gene expression atlas of the central nervous system based on bacterial artificial chromosomes

The mammalian central nervous system (CNS) contains a remarkable array of neural cells, each with a complex pattern of connections that together generate perceptions and higher brain functions. Here we describe a large-scale screen to create an atlas of CNS gene expression at the cellular level, and to provide a library of verified bacterial artificial chromosome (BAC) vectors and transgenic mouse lines that offer experimental access to CNS regions, cell classes and pathways. We illustrate the use of this atlas to derive novel insights into gene function in neural cells, and into principal steps of CNS development. The atlas, library of BAC vectors and BAC transgenic mice generated in this screen provide a rich resource that allows a broad array of investigations not previously available to the neuroscience community.     

禁带区域内负的群速度

研究超声波经过两个烧结样品的行为.两个烧结样品为有序的面心立方结构,它们的结构几乎相同.研究表明:在两个有序的准均匀的介质中分别有一个禁带区域.就禁带区域而言,在两个样品中产生禁带的区域非常接近.同时在禁带出现的区域群速度为负值.我们的结果表明群速度的负值的确存在于有序介质中的禁带区域内.     

传统农业生态系统的保护

世界的生物多样性很大程度上受到传统农业耕作方式的保护。这些生态上复杂的农业系统与作物遗传多样性中心相联系,有传统的栽培品种或“地方品种”,作为世界作物遗传资源的重要组成,还有野生的植物和动物种群,作为生物资源服务于人类。