The potential to encode sex,age, and individual identity in the alarm calls of three species of Marmotinae

In addition to encoding referential information and information about the sender’s motivation, mammalian alarm calls may encode information about other attributes of the sender, providing the potential for recognition among kin, mates, and neighbors. Here, we examined 96 speckled ground squirrels (Spermophilus suslicus), 100 yellow ground squirrels (Spermophilus fulvus) and 85 yellow-bellied marmots (Marmota flaviventris) to determine whether their alarm calls differed between species in their ability to encode information about the caller’s sex, age, and identity. Alarm calls were elicited by approaching individually identified animals in live-traps. We assume this experimental design modeled a naturally occurring predatory event, when receivers should acquire information about attributes of a caller from a single bout of alarm calls. In each species, variation that allows identification of the caller’s identity was greater than variation allowing identification of age or sex. We discuss these results in relation to each species’ biology and sociality.     

核电站的应急计划

每座核电站都十分注重安全,设有一系列的安全保护监督测量措施,设备先进,自动控制程度高,技术要求严格,人员素质精良.一个目标,就是从各个方面来保证安全.事实也是这样,世界核电史上一直保持很高的安全运行记录,核电迄今仍是安全的能源.但这并不是说核电就绝对不会发生严重事故.一个错综复杂的大型工程,小事故就会涉及到各方面,何况人也有误操作的时候.     

西印度洋地区海草生态系统

海草是海洋被子植物,广泛分布在温带和热带的海岸带水域,是地球上水生生态系统中最具生产力的生物之一.     

西印度洋地区海草生态系统

海草是海洋被子植物,广泛分布在温带和热带的海岸带水域,是地球上水生生态系统中最具生产力的生物之一.     

Primary colonization and breakdown of igneous rocks by endemic, succulent elephant trees (Pachycormus discolor) of the deserts in Baja California, Mexico

Trees growing in rocks without soil are uncommon. In two arid regions in Baja California, Mexico, field surveys found large numbers of rock-colonizing elephant trees (Pachycormus discolor (Benth.) Coville ex Standl. (Mexican name: copalquin) growing in igneous rocks (granite and basalt) as primary colonizers without the benefit of soil or with a very small amount of soil generated by their own growth. Many adult trees broke large granite boulders and were capable of wedging, growing in, and colonizing rocks and cliffs made of ancient lava flows. This is the first record of a tree species, apart from the previously recorded cacti, capable of primary colonization of rocks and rock rubble in hot deserts.     

走进核能的世界 了解中国的核电

<正>人类从钻木取火到工业革命再到信息时代,能源的使用从木材到煤炭与石油再到电磁能与核能,每次能源应用的变革都推动了人类社会加速发展,同时能源问题也成为关系到国计民生乃至国家安全的重大课题。传统的煤炭和石油在我国的能源结构中占据了绝对主导的位置,但随着我国居民生活水平的提高使这些传统能源的消耗不断增加,进而更加凸显出我国能源结构不合理的基本国情和"软肋"。走一条清洁、高效、安全、可持续的能源发展之路,是向污染宣战、加强生态环保的节能减排措施,促进大气质量改善的必然选择。自上世纪九十年代初开始,我国大陆     

法国核电:技术标准化奠定成功基石

美国核管会原主席塞林曾这样诙谐地说：法国有200多种奶酪，但只有一种核电机组。这就是技术标准化——法国正在运行的58台核电机组全部采用压水堆技术。