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A methodology is developed to identify, as units of study, each decrease in the value of a stock from a given maximum price level. A critical level in the amount of price declines is found to separate a segment operating under a random walk from a segment operating under a power law. This level is interpreted as a point of phase transition into a self-organized system. Evidence of self-organization was found in all the stock market indices studied but in none of the control synthetic random series. Findings partially explain the fractal structure characteristic of financial time series and suggest that price fluctuations adopt two different operating regimes. We propose to identify downward movements larger than the critical level apparently subject to the power law, as self-organized states, and price decreases smaller than the critical level, as a random walk with the Markov property.

Gravitational axial and chiral anomalies in a noncommutative space are examined through the explicit perturbative computation of one-loop diagrams in various dimensions. The analysis depend on how gravity is coupled to noncommutative matter fields. Delbourgo-Salam computation of the gravitational axial anomaly contribution to the pion decay into two photons, is studied in detail in this context. In the process we show that the two-dimensional chiral pure gravitational anomaly does not receive noncommutative corrections. Pure gravitational chiral anomaly in 4k+2 dimensions with matter fields being chiral fermions of spin-1/2 and spin-3/2, is discussed and a noncommutative correction is found in both cases. Mixed anomalies are finally considered in both cases., 29+1 pages, harvmac file, no figures