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Dynamical topology and statistical properties of spatiotemporal chaos
For spatiotemporal chaos described by partial differential equations, there
are generally locations where the dynamical variable achieves its local
extremum or where the time partial derivative of the variable vanishes
instantaneously. To a large extent, the location and movement of these
topologically special points determine the qualitative structure of the
disordered states. We analyze numerically statistical properties of the
topologically special points in one-dimensional spatiotemporal chaos. The
probability distribution functions for the number of point, the lifespan, and
the distance covered during their lifetime are obtained from numerical
simulations. Mathematically, we establish a probabilistic model to describe the
dynamics of these topologically special points. In despite of the different
definitions in different spatiotemporal chaos, the dynamics of these special
points can be described in a uniform approach.Comment: 6 pages, 5 figure
Acid-volatile sulfide and simultaneously extracted metals in surface sediments of the southwestern coastal Laizhou Bay, Bohai Sea: Concentrations, spatial distributions and the indication of heavy metal pollution status
Surface sediments were collected from the coastal waters of southwestern Laizhou Bay and the rivers it connects with during summer and autumn 2012. The acid-volatile sulfide (AVS) and simultaneously extracted metals (SEM) were measured to assess the sediment quality. The results showed that not all sediments with [SEM]-[AVS] > 0 were capable of causing toxicity because the organic carbon is also an important metal-binding phase in sediments. Suppose the sediments had not been disturbed and the criteria of US Environmental Protection Agency had been followed, heavy metals in this area had no adverse biological effects in both seasons except for few riverine samples. The major ingredient of SEM was Zn, whereas the contribution of Cd - the most toxic metal studied - to SEM was 0 were capable of causing toxicity because the organic carbon is also an important metal-binding phase in sediments. Suppose the sediments had not been disturbed and the criteria of US Environmental Protection Agency had been followed, heavy metals in this area had no adverse biological effects in both seasons except for few riverine samples. The major ingredient of SEM was Zn, whereas the contribution of Cd - the most toxic metal studied - to SEM was <1%. The distributions of AVS and SEM in riverine sediments were more easily affected by anthropogenic activity compared with those in marine sediments. (C) 2013 Elsevier Ltd. All rights reserved
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