Time keepers abound very cell in the body has its own little clock, according to Emi Nagoshi, Ueli Schibler (University of Geneva, Switzerland), and colleagues. These peripheral clocks may be closely related to the body’s central clock—the suprachiasmatic nucleus (SCN). Neurons of the SCN maintain circadian gene expression for long periods of time. Other cells, however, were thought to rely on ...

We propose a new approach to forecasting stock returns in the presence of structural breaks that simultaneously affect the parameters of multiple portfolios. Exploiting information in the cross-section increases our ability to identify breaks in return prediction models and enables us to detect breaks more rapidly in real time, thereby allowing the parameters of the predictive return regression...

We generalize the concept of a break by considering pairs of arbitrary rounds. We show that a set of home-away patterns minimizing the number of generalized breaks cannot be found in polynomial time, unless P=NP. When all teams have the same break set, the decision version becomes easy; optimizing remains NP-hard.