Teaching in tandem-running ants

The ant Temnothorax albipennis uses a technique known as tandem running to lead another ant from the nest to food--with signals between the two ants controlling both the speed and course of the run. Here we analyse the results of this communication and show that tandem running is an example of teaching, to our knowledge the first in a non-human animal, that involves bidirectional feedback between teacher and pupil. This behaviour indicates that it could be the value of information, rather than the constraint of brain size, that has influenced the evolution of teaching.     

Suppression of star formation in early-type galaxies by feedback from supermassive black holes

Detailed high-resolution observations of the innermost regions of nearby galaxies have revealed the presence of supermassive black holes. These black holes may interact with their host galaxies by means of 'feedback' in the form of energy and material jets; this feedback affects the evolution of the host and gives rise to observed relations between the black hole and the host. Here we report observations of the ultraviolet emissions of massive early-type galaxies. We derive an empirical relation for a critical black-hole mass (as a function of velocity dispersion) above which the outflows from these black holes suppress star formation in their hosts by heating and expelling all available cold gas. Supermassive black holes are negligible in mass compared to their hosts but nevertheless seem to play a critical role in the star formation history of galaxies.     

Enforced altruism in insect societies

Cooperation among workers and their seeming altruism result from strict policing by nestmates.     

地理信息系统数据标准研究

地理信息是近年来地学界比较热门的话题,它是信息高速公路建设中全球空间数据基础设施的主要内容。本文地地理信息系统技术和标准的发展问题做了系统的分析,通过地理信息系统标准在政府、国家和国际间的历程,并结合我国的发展状况,展现了地理信息共享的地理信息系统发展趋势。