Rats with medial prefrontal cortex or sham control lesions were tested on an eight-arm radial maze task to examine memory for the temporal order of a variable and a constant sequence of spatial locations as a function of temporal distance. During the study phase of each trial, rats were allowed to visit each of eight arms once in an order that was randomly selected or fixed for that trial. The ...

We propose a generic spatial domain control scheme for a class of nonlinear rotary systems of variable speeds and subject to spatially periodic disturbances. The nonlinear model of the rotary system in time domain is transformed into one in spatial domain employing a coordinate transformation with respect to angular displacement. Under the circumstances that measurement of the system states is ...

This paper examines the determinants of bid-ask spreads and their behaviour around corporate earning announcement dates, for a sample of UK firms over the period 1986-94. The paper finds that closing daily spreads are affected by order processing costs (proxied by trading volumes), inventory control costs (trading volumes and return variability) and asymmetric information (unusually high tradin...

introduction in 1950s, only 30% of the world's population lived in urban areas. by 2000, that proportion increasedup to 47%, and by 2050 the estimated number will be around 72%. urban sprawl, an undesirable type of urban growth, is one of the major concerns ofthe city planners and administrators. understanding urban patterns, dynamic processes, and their relationships is a primary objectiv...