RNF169 flips the repair switch P oulsen et al. describe an enzyme that helps a cell determine which repair method to use on DNA double-strand breaks (DSBs). Unrepaired DSBs can incite genomic chaos, spurring sections of chromosomes to relocate or even vanish. To ensure that doesn’t happen, a cell wraps a molecular bandage around a DSB. Enzymes arrive at the injury and ubiquitylate the surroundi...

This article presents a physical biology approach to understanding organization and segregation of bacterial chromosomes. The author uses a “piston” analogy for bacterial chromosomes in a cell, which leads to a phase diagram for the organization of two athermal chains confined in a closed geometry characterized by two length scales (length and width). When applied to rod-shaped bacteria such as...

(Originally and inspirationally entitled, 'A hybrid geocomputation model for operational land-use and transport simulation.) ABSTRACT There are indications that the current generation of simulation models in practical, operational uses has reached the limits of its usefulness under existing specifications. The relative stasis in operational urban modeling contrasts with simulation efforts in ot...