In connection with recent experiments on excitation in which Mott insulators change to conductors, we study the properties of excited states beyond gap as quasi-stationary for a two-dimensional Hubbard (t-t'-U) model at half filling. A variational Monte Carlo method is used trial wave functions paramagnetic or normal (PM), superconducting dx2-y2-wave (d-SC), isotropic s-wave, and extended s-wav...

The regulation of quantal size through pre- rather than postsynaptic mechanisms has recently received considerable attention as a potential mechanism for plasticity. Vesicular transporters catalyze the filling of synaptic vesicles with transmitter and are thus potential substrates for such presynaptic regulation. In this issue of Neuron, Prado et al. pursue this line of investigation and show t...