Run length and the predictability of stock price reversals

Survival analysis is used to estimate time-varying probabilities of price reversals using daily data for the Australian All Ordinaries Price Index. Lagged price changes lead to persistence (shortening) in a price run if they are of the same (opposite) sign as the run. An increase in the number of runs observed in the previous 30 days also increases the probability of price reversal. The predictive accuracy of the models is assessed using a probability scoring rule. Consistent with market efficiency, the estimated models are less accurate than the random walk model in predicting the length of individual price runs out-of-sample. Copyright 2005 Accounting and Finance Association of Australia and New Zealand..

Effects of the Erika oil spill on the common starfish Asterias rubens, evaluated by field and laboratory studies.

Impacts of the Erika oil spill on the common starfish Asterias rubens were investigated in the field and using laboratory experiments based on contamination via food at different stages of the starfish reproductive cycle. Two months after the shipwreck, levels of hydrocarbons characteristic of Erika fuel were significantly higher in pyloric ceca and body wall of A. rubens from a contaminated site, compared with control animals from an unpolluted reference area. Concomitant immunological responses and detoxification enzyme activity (CYP1A) were enhanced in the impacted starfish, suggesting rapid biotransformation processes. This was confirmed by laboratory experiments which showed a fast PAH uptake during the 10 first days of contamination and the start of biotransformation processes from the third day. Our study confirms benzo(a)pyrene hydroxylase activity (BPH) in A. rubens and demonstrates the influence of CYP1A in the conversion of insoluble PAHs into soluble derivatives in this species for the first time. The rapidity of decontamination could explain why starfish growth, level of motile activity, reproductive investment, energy storage, and larval development were not significantly affected by these contaminants.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe