tem cells use the miRNA pathway to drive mitosis forward through a stage when other cells would stall, according to results from Steven Hatfield, Halyna Shcherbata, Hannele Ruohola-Baker (University of Washington, Seattle, WA), and colleagues. The remarkable ability of stem cells to divide relentlessly while surrounding cells are quiescent is key to their function. Stems cells have been noted t...

The so-called dividing instant (DI) problem is an ancient historical puzzle encountered when attempting to represent what happens at the boundary instant which divides two successive states. The specification of such a problem requires a thorough exploration of the primitives of the temporal ontology and the corresponding time structure, as well as the conditions that the resulting temporal mod...