Fenfluramine challenge in anxious children.

The study objective was to determine if serotonergic challenge with oral racemic fenfluramine would differentiate between childhood anxiety disorders in comparison to normal controls. Subjects were 24 children with anxiety diagnoses (DSM-IIIR) by structured interview, and 14 normal controls (ages 7 - 14 years) matched for age and sex. All subjects were given a standard challenge dose of d,1-fenfluramine (1 mg/kg) followed by serial assessments of cardiovascular, neurohormonal, and mood parameters over a five hour period.

Are there really no evolutionarily stable strategies in the iterated prisoner's dilemma?

The evolutionary form of the iterated prisoner's dilemma (IPD) is a repeated game where players strategically choose whether to cooperate with or exploit opponents and reproduce in proportion to game success. It has been widely used to study the evolution of cooperation among selfish agents. In the past 15 years, researchers proved over a series of papers that there is no evolutionarily stable strategy (ESS) in the IPD when players maintain long-term relationships.