Selection intensity, fluctuations

Figure 1. Intensity fluctuations in a CdSe-ZnS NC under continuous laser illumination at room temperature. Dotted horizontal line was selected as a threshold to divide off and on states.

Fluctuations of selection intensity have received much attention in population genetics because it is quite reasonable to assume that some relevant environmental variables change the fitness value of different genotypes over generations. Deterministic treatments derive from the model of Haldane and Jayakar stochastic fluctuations were first considered by Kimura and Dempster. Recent reviews are those of Felstein and Maynard-Smith and Hoekstra. ... 

Chemical reactions will take place only when the reactant molecules are in intimate contact. In some cases, especially with very fast reactions or viscous liquids, segregation of the reactants can exist, which make the reaction rates and selectivities dependent on the mixing intensity. In chemical reactor engineering, the assumption is usually made that only mean concentrations need be considered. In reality, concentration values fluctuate about a mean, and in some cases these fluctuations must be considered in detail. This field is very complex and is still the subject of much research. This example serves only to introduce these concepts and to show how simulations can be made for certain simple situations. 

ASAXS experiments were conducted on Beamline II-2 at the Stanford Synchrotron Radiation Laboratory (SSRL). X-ray energies 5 and 100 eV below the measured K edge for Ni in the ionomer (8333 eV in Ni metal) were selected by a double-crystal monochromator using planar Sl(lll) crystals with a nominal resolution of zH eV. The scattering apparatus has been described in detail else rtiere[35,36]. The data were corrected for transmittance of the sample and fluctuations in Incident beam Intensity and are shown herein on a consistent relative intensity scale. 

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