Speaker: Ilya Nemenman Winship Distinguished Research Professor of Physics and Biology, Emory University Title: Berg-Purcell bound, revisited Abstract: Berg-Purcell bound on the accuracy, with which a cellular sensor can sense concentration of a diffusing ligand, is one of the classic results in modern biophysics, which has affected our understanding of structure, function, and behavior of microorganisms in innumerable ways. In this presentation, I will explore a series of recent results extending the classic bound: What if the concentration of the ligand changes with time? What if there are many ligand and receptor species, all binding to each other? What if the cellular detectors are large enough to require a nontrivial communication across their span? It turns out that the Berg-Purcell setup still has a lot left in it to explore.