Liquids, such as water or oil, can form droplets that are held together by surface tension—a cohesive force that causes the surface of many liquids to behave as an elastic membrane. Because liquid droplets are fairly simple to study and control under different conditions, they have fascinated experimentalists and theoreticians—including Laplace, Gauss, Poincarè, Chandrasekhar, Bohr, and Wheeler...

learnt that all living organisms grow, and that growth requires an increase in both cell number and cell size. But how is this controlled? Insulin and insulin-like growth factors (IGFs; see the ‘Background’ box) play a critical role, and they are also implicated in medical conditions such as cancer and diabetes. So understanding their mechanism of action at the molecular level will have importa...

Pascal Houillier,* Joël Coste,* and Marc Froissart* *Department of Physiology, Paris Descartes University, Paris, France; Department of Physiology, Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris, Paris, France; INSERM, Centre de Recherche des Cordeliers, UMRS 872, Paris, France; Biostatistics and Epidemiology Unit, Hôpital Cochin, Assistance PubliqueHôpitaux de Paris, ...

Social insect societies come in many different shapes and sizes. Bumble bee and Leptothorax ant colonies contain only a hundred individuals or less. Sizes then increase through a wide range of species including honey bees−with up to 30,000−to the huge colonies of army ants and leaf cutter ants which can contain millions of individuals. As a consequence of natural selection, the size of an insec...

1. Holding a meeting At the SRI Artificial Intelligence Lab, we have a long history of building autonomous robots, from the original Shakey (remember the STRIPS planner?) through Flakey [Congdon 1993] and more recently, the Pioneer class of small robots. Our current research focuses on realtime vision for robots, and multirobot planning using an agent-oriented architecture. For the AAAI contest...