3 research outputs found

### Stress-energy of a quantized scalar field in static wormhole spacetimes

An analytical approximation of $$ for a quantized scalar field in
a static spherically symmetric spacetime with a topology $S^2 \times R^2$ is
obtained. The gravitational background is assumed slowly varying. The scalar
field is assumed to be both massive and massless, with an arbitrary coupling
$\xi$ to the scalar curvature and in a zero temperature vacuum state. It is
demonstrated that for some values of curvature coupling the stress-energy has
the properties needed to support the wormhole geometry.Comment: 21 pages, revte

### Vacuum polarization of a scalar field in wormhole spacetimes

An analitical approximation of $$ for a scalar field in a static
spherically symmetric wormhole spacetime is obtained. The scalar field is
assumed to be both massive and massless, with an arbitrary coupling $\xi$ to
the scalar curvature, and in a zero temperature vacuum state.Comment: 10 pages, RevTeX, two eps figure

### Conditioned suppression or facilitation as a function of the behavioral baseline

Rats were exposed to a multiple schedule of reinforcement. During one component, a bar-press was followed by reinforcement only if it occurred between 15 and 20 sec after the previous response. This differential-reinforcement-of-low-rate (DRL) schedule produced a typical slow rate of responding. During the other component, reinforcement followed the first response to be emitted during limited periods of time which occurred at fixed intervals. These fixed-interval schedules with a limited hold produced higher response rates, described as `interval' or `ratio-like' behavior. Responding during the DRL component increased in frequency during a tone which ended with an unavoidable shock of low intensity, but decreased during the tone when the shock intensity was raised. The `interval' and `ratio-like' responding decreased in frequency during the tone at all shock intensities. Initial acceleration of the DRL responding appeared to be due to adventitious punishment of collateral behavior which was observed between the bar-presses. The more severe conditioned suppression during the fixed-interval components might be the result of the lower probability of reinforcement after any single response