(Produced on acid-free paper)

It has recently been shown that local search issurprisingly good at nding satisfying assignments for certain computationally hard classes of CNF formulas. The performance of basic local search methods can be further enhanced by introducing mechanisms for escaping from local minima in the search

A phasic stimulus directed to the rear of a crayfish (Procambarus clarkii) creates mechanosensory input to the lateral giant (LG) interneuron, a command neuron for escape. A single LG spike is necessary and sufficient to produce a highly stereotyped tail flip that thrusts the animal away from

;mixed random walk", for escaping from local minima. We present experimental results showing how this strategy allows us to handle formulas that are substantially larger than those that can be solved with basic local search. We also present a detailed comparison of our random walk strategy with simulated

gle's medium (DMEM), then treated with serum- and phosphate-free DMEM containing 100 pM ascorbate with or without ISO (10 pLM final concentration) and incubated at 37°C for 15 min. The cells were then assayed for whole-cell phosphorylation as described (7). The extent of receptor phosphorylation was quantitated with a Molecular Dynamics phosphorim-aging system and ImageQuant software. 23. We thank R.J. Lefkowitz for encouragement and in-sightful reading of the manuscript and members of his laboratory for antisera to,BARK1 and-2, antisera to 3-arrestin-1 and-2, wild-type,BARK1, 3-arres-tin-1 and-2 cDNA constructs, and wild-type and phosphorylation site-deficient f32AR cDNA con-

The effect of silver nanoparticles on synaptic responses in the lateral giant escape circuit of the crayfish

responsible for exciting the lateral giant neuron and initiating single tail flips in response to phasic mechanical stimuli to the tail of crayfish. It was shown that the exci-tation of some tactile interneurons by tac-tile afferents antifacilitates extensively at low repetition rates

subordinate retreats and escapes from the attacks and approaches of the dominant (Issa et al., 1999). We used high-speed videography and electrical recordings of aquarium field potentials to monitor the release of aggressive and defensive behavior, including the activation of neural circuits for four

Serotonin and octopamine have opposite modulatory effects on the crayfish’s lateral

Extrinsic systems were shown to control the excitability of the neurones which mediate tail-flip escape in the crayfish. Restraint suppresses the escape mediated by giant fibres and some, but not all, categories of non-giant mediated escape; autotomy of claws increases the excitability of non