Fitness landscapes parameters

During the screening, a large amount of fitness data is generated, but only the fitness information of the improved mutants is used to continue to the next round of evolution. The large ensemble of less fit mutants provides a view of the local fitness landscape. By analyzing these data, certain statistical landscape parameters can be... 

More careful examination of this shape reveals two important facts, (a) Plots of ssq as a function of k at fixed Io are not parabolas, while plots of ssq vs. Io at fixed k are parabolas. This indicates that Io is a linear parameter and k is not. (b) Close to the minimum, the landscape becomes almost parabolic, see Figure 4-6. We will see later in Chapter 4.3, Non-Linear Regression, that the fitting of non-linear parameters involves linearisation. The almost parabolic landscape close to the minimum indicates that the linearisation is a good approximation. 

The exponent m cannot be regarded as a fitting parameter but depends on the symmetry of the system. In most cases, m = 3/2 [16, 140, 158, 166, 167, 174, 175], but m = 2 for highly symmetric systems, such as aligned Stoner-Wohlfarth particles. In particular, the m = 3/2 law is realized for misaligned Stoner-Wohlfarth particles and for most domain-wall pinning mechanisms [5], Experimental values of m tend to vary between 1.5 to 2 [136, 158]. Linear laws, where m = 1, are sometimes used in simplified models, but so far it hasn t been possible to derive them from physically reasonable energy landscapes [5, 16, 176]. The same is true for dependences such as /H- l/H0 [177], where series expansion yields an m = 1 power law. 

Moreover, this fitting shows that in the considered temperature-frequency landscape, only the temperature dependence of As = As(T) and r = x(T) is observed, while the other parameters B, (3, A, and q are not temperature-dependent. Thus, the proposed phenomenological model (114) as a modification of the CD function (21) with a conductivity term could be successfully applied for simultaneous fitting of dc-conductivity, the main process, and the EW presented in the master plots (see Fig. 27). 

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