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#           Analog (polynomial) model of bursting
#           electrical activity in pancreas beta-cells.
#
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#            Problem definition
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#
#       parameter values defining model
#
p a=0.25,eta=0.75,uhat=1.5,beta=4,ubeta=-0.954,e=0.0025
#
#
#       function definitions
#
F(u)=a*((u-uhat)^2-eta^2)
G(u,c)=u^3-3*(u+1)+c
#
#      differential equations
#
u'=du
du'=-F(u)*du-G(u,c)-e*(beta*(u-ubeta)-c)
c'=e*(beta*(u-ubeta)-c)
#
#      initial conditions (optional)
#
u(0)=-1.3368
du(0)=0.0031
c(0)=1.38
#
@ total=400,xlo=0,xhi=400,ylo=-2,yhi=4,dt=0.05,maxstor=8500
#
d