T he scientist Ahmed Zewail (1946–2016) was awarded the Nobel Prize in Chemistry in 1999 for his contributions to femtochemistry, the field that studies chemical changes on the time scales on which atoms move—femtoseconds (fs). Femtochemistry experiments follow the electronic or structural dynamics of a molecule by first exciting it with a femtosecond “pump” laser pulse, and then observing it u...

Weekly box office revenues for approximately 100 successful motion pictures are analyzed by use of a finite mixture regression technique to determine if regular sales patterns emerge. Based on an exponential decay model applied to market share data, four clusters of movies, varying in opening strength and decay rate, are found. Characteristics of the clusters and implications for future researc...