euronal growth cones are guided by both attractive and repulsive signals during development. Until now, one part of the guidance signaling system appeared relatively straightforward: Rac GTPases stimulate attraction, while Rho GTPases stimulate repulsion. But on page 1117, Bashaw et al. describe the activity of a new Rho guanine nucleotide exchange factor in Drosophila melanogaster , GEF64C, th...

We study a class of attractive spin systems. We prove that for these processes, the system dies out when the parameters are on the critical surface. We also prove that the supercritical process survives with positive probability in a suuciently thick space-timèslab'.

hydrogen bonding is considered by many to be the ‘master key’ of molecular recognition — owing to its relatively predictable strength and directionality — and plays a major role in the assembly of diverse non-covalent assemblies1. Consequently, the study and exploitation of hydrogen bonds has been central to the development of modern supramolecular chemistry. In particular, numerous applied set...

We study the phase space of initial conditions for brane inflation, and find that including the effects of the Dirac-Born-Infeld (DBI) kinetic term dramatically improves previous estimates on the amount of fine tuning of initial conditions necessary for inflation, even for models dominated by slow roll. Two effects turn out to be important for the phase space analysis: restrictions on the total...

Spontaneous thoughts, the output of a broad category of uncontrolled and inaccessible higher order mental processes, arise frequently in everyday life. The seeming randomness by which spontaneous thoughts arise might give people good reason to dismiss them as meaningless. We suggest that it is precisely the lack of control over and access to the processes by which they arise that leads people t...

one of the most important topics in the field of jurisprudence and interpretation of the noble quran is freedom of religion which is also drawn into the political sphere. discussions on the seeming conflict between verses of sword and denial of duress have aroused controversies among researchers. one of the four following possible relationships can be established between verses of sword and den...

The nature of magnetic monopoles in an SO(3) gauge theory is explored by examining how they scatter charged particles. Peripheral scattering, where the momentum transfer is much less than the mass of the charged vector bosons, is just as it is in the earlier theory of Dirac. The scattering wave function is discussed with some rigor since its behavior is not uniform in the forward direction. The...

Steps to STIMulation W hen ER calcium levels plummet, an ER membrane calcium sensor called STIM1 directly activates plasma membrane (PM) channels to top up the cell’s calcium. Jen Liou, Tobias Meyer, and colleagues (Stanford University Medical School, Stanford, CA) have now uncovered the molecular steps of STIM1’s pathway to the PM and show that those steps don’t take STIM1 very far. STIM1 sits...

Events VaBio After Hours Adventures Mountain River Raft Trip AFTER Roseanne M. Ford received her Ph.D from the University of Pennsylvania in 1989, she came to University of Virginia to continue her work on bacterial chemotaxis, the ability of motile bacteria to direct their migration toward beneficial chemicals and away from detrimental ones. That same year, an oil spill, which occurred in Prin...

We show how attractive interactions dramatically influence emulsion rheology. Unlike the repulsive case, attractive emulsions below random close packing, φ(RCP), can form soft gel-like elastic solids. However, above φ(RCP), attractive and repulsive emulsions have similar elasticities. Such compressed attractive emulsions undergo an additional shear-driven relaxation process during yielding. Our...