A financial index of the New York stock exchange, the S&P500, is analyzed at 1 min intervals over the 13 yr period, January 84–December 96. We quantify the correlations of the absolute values of the index increment. We find that these correlations can be described by two different power laws...

We study the volatility of the S&P500 stock index from 1984 to 1996 and find that the volatility distribution can be very well described by a log-normal function. Further, using detrended fluctuation analysis we show that the volatility is power-law correlated with Hurst exponent α ≌ 0.9.

Although H2O has been the topic of considerable research since the beginning of the century, the peculiar physical properties are still not well understood. We discuss recent experiments and simulations relating to the hypothesis that, in addition to the known critical point in water, there...

We investigate for the first time spin-lattice relaxation caused by particles diffusing in disordered environments. For noninteracting particles on a fractal substrate with fractal dimension df and diffusion exponent dw, we find that the NMR correlation functions G(q)(t) are asymptotically...