Systems Biology (Methods in Molecular Biology)

be adjusted to predictively regulate the system response. It is

worthwhile noticing that multiple equilibria could be generated

by assuming other forms for the functiong, thus allowing to

establish effective mathematical models for reproducing a wide

variety of biological dynamics.

Thefast-dynamicsof Eq.7 is described by a new time variable

srelated to the old onet by the relationships¼ t/τ, which

corresponds to the following differential equality for the instanta-

neous time variation:

0.5 1 1.5 2

0.5

1

1.5

2

u

w

a

b

0.5 1 1.5 2

0.5

1

1.5

2

u

w

Fig. 9Relative positions of the straight linew¼u(dotted) and the curvew¼λg(u)(continuous) corresponding
to different values ofλ.(a) Caseλ¼ 1 <λcwithp¼1,ℓ¼1. (b) Caseλ¼ 2 >λcwithp¼1,ℓ¼ 1

116 Chiara Simeoni et al.