Giving infecting bacteria a little freedom early on can be good for the host, according to a new study by Rotta et al. (page 657). Confining the bugs too quickly, they find, can tie up the immune cells that need to spread the word. Certain bacteria, such as Mycobacterium tuberculosis and Salmonella, are quickly surrounded by macrophages, dendritic cells, and other immune cells that seal off the...

The traditional paradigm for learning and training of operators in complex systems is discussed and criticised to react on the strong influence (the doctrine of 'mental logic') coming from research carried out in artificial intelligence (AI). The most well known arguments against the AI-approach are presented and discussed in relation to expertise, intuition and implicit knowledge. The importan...