Effects of catecholaminergic drugs on systems of reward and punishment in experiments on cats

A common assumption in special education is that temporal limits for a task should be expanded so that ample time is provided for completing the work. This study describes the opposite strategy of restricting temporal limits to augment academic performance. Three educable retarded children received token reinforcement contingent on the number of correct math problems answered during daily sessions. A reversal design was used to assess the effects of an abrupt reduction in time limits (20-5-20 min) and a graduated sequence of reductions (20-15-10-5-20 min). The graduated sequence resulted in rate increases of correct responding ranging from 125% to 266% and these gains endured when temporal limits were again expanded. In contrast, the abrupt shift produced interfering emotional behaviors and rate decreases in academic performance of 25% to 80%. The findings indicate that systematically restricting temporal limits for an academic task can further enhance the performance of slow learners already maintained by a token system.     

Topological analysis of isopower manifolds in distillation

Separation flowsheets for three-, four-, and five-component mixtures are considered. Graphs analysis of the arrangement of feed-composition regions is performed to find the optimum separation flowsheet.     

Synthesis of Optimal Distillation Flowsheets Consisting of Columns with Various Numbers of Sections

Distillation flowsheets consisting of simple columns, both simple columns and complex columns with side streams, and simple column–complex column sequences are considered for zeotropic four-component mixtures. Applicability criteria are suggested for the complex columns.