Migrating fi broblasts assemble a dendritic network of branched actin fi laments that drives the formation of a lamellipodial protrusion at their leading edge. Haynes et al. reveal that, like a topiarist guiding the growth of a tree, a protein called GMF␤ " prunes " this actin network in order to guide the cell's migration towards certain directional cues (1). Branched actin networks form when ...

We develop some useful techinques for integrating over Higgs branches in supersymmetric theories with 4 and 8 supercharges. In particular, we define a regularized volume for hyperkahler quotients. We evaluate this volume for certain ALE and ALF spaces in terms of the hyperkahler periods. We also reduce these volumes for a large class of hyperkahler quotients to simpler integrals. These quotient...

The politics of the Internet is a common theme in cybertheory, though commentators work with a variety of different notions of the political. Among the main issues are the question of whether the Internet may enhance or detract from the processes of deliberation traditionally seen as crucial to a strong civil society, along with that of whether online voting could usher in an era direct democra...

For more than 40 years now, the developing kidney has served as a model paradigm for epithelial-mesenchymal interactions. The principles of inductive signaling, epithelial cell differentiation, and pattern formation are now being addressed with modern genetic and biochemical tools. In addition to the mammalian kidney organ culture model, both zebrafish and Xenopus laevis demonstrate great poten...

In this paper we investigate the structure of the shortest co-cycle base(or SCB in short) of connected graphs, which are related with map geometries, i.e., Smarandache 2dimensional manifolds. By using a Hall type theorem for base transformation, we show that the shortest co-cycle bases have the same structure (there is a 1-1 correspondence between two shortest co-cycle bases such that the corre...