Austin. R. H. Bacterial metapopulations in nanefatiticated landscapes. Prot. Natl. Acad. Set USA 103. 17290-17295 (2006). 39. Ge/ajda. P.. Keymer. L. Chaikin, P. & Austin. It A wall of funnels concentrates swimming bacteria. I. Bacterial. 189. 8704-8707 (2007). 40. Mannik. L. Thiessen. It. Galeda. P.. Ke