Daisy model

The activity in terms of 1st order rate constant khcalc was calculated in Table 2 from (8) and (9) with effective diffusivity Dejf=5.3-10 6 m2/s and intrinsic rate constant =33000 Nm3/h/m3 = 23 s"1 fitted to the measurements. This simple and useful method models the measured influence of particle size satisfactorily for a first optimization of particle size and shape. The 35% higher activity measured for the 9-mm Daisy compared to the 12-mm Daisy, however, exceeds the 25% expected from (8), and this illustrates the importance of measuring the activity of the actual shape. 

At the same time, one should be aware that the advocates of Gaia posed the problem of the homeostatic properties of the biosphere more precisely than Vernadsky himself based on data collected in the 50 years after Vernadsky wrote down his conclusions. Vernadsky was in no position to make a numerical model of the biosphere comparable with the daisy world modeP and other models of Gaia (Schellnhuber, Wenzel, 1998). In the Vernadskian tradition mathematical modelling of the biosphere was pioneered by Moiseev with colleagues (e.g., Moiseev et aL, 1985). 

Saccomani, M.R, Audoly, S., Bellu, G., and DAngib, L. 2010. Testing global identifiabUity ofbiological and biomedical models with the DAISY software. Comp. Biol. Med. 40 402-407. 

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