Temporal structure and gain-loss asymmetry for real and artificial stock indices.

Previous research has shown that for stock indices, the most likely time until a return of a particular size has been observed is longer for gains than for losses. We demonstrate that this so-called gain-loss asymmetry vanishes if the temporal dependence structure is destroyed by scrambling the time series. We also show that an artificial index constructed by a simple average of a number of individual stocks display gain-loss asymmetry-this allows us to explicitly analyze the dependence between the index constituents. We consider mutual information and correlation-based measures and show that the stock returns indeed have a higher degree of dependence in times of market downturns than upturns.

Early initiation of eptifibatide in the emergency department before primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: results of the Time to Integrilin Therapy in Acute Myocardial Infarction (TITAN)-TIMI 34 trial.

BACKGROUND: Early restoration of epicardial flow before primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) has been associated with improved clinical outcomes. METHODS: We hypothesized that early administration of the glycoprotein IIb/IIIa inhibitor eptifibatide in the emergency department (ED) would yield superior epicardial flow and myocardial perfusion before primary PCI compared with initiating eptifibatide after diagnostic angiography in the cardiac catheterization laboratory (CCL). Three hundred forty-three patients with STEMI were randomized to either early ED eptifibatide (n = 180) or CCL eptifibatide (n = 163). RESULTS: The primary end point (pre-PCI corrected TIMI frame count) was significantly lower (faster flow) with early eptifibatide (77.5 +/- 32.2 vs 84.3 +/- 30.7, P = .049). The incidence of normal pre-PCI TIMI myocardial perfusion was increased among patients treated in the ED versus CCL (24% vs 14%, P = .026). There was no excess of TIMI major or minor bleeding among patients treated in the ED versus CCL (6.9% [12/174] vs 7.8% [11/142], P = NS). CONCLUSION: A strategy of early initiation of eptifibatide in the ED before primary PCI for STEMI yields superior pre-PCI TIMI frame counts, reflecting epicardial flow, and superior TIMI myocardial perfusion compared with a strategy of initiating eptifibatide in the CCL without an increase in bleeding risk.