st: estimating shifting logistic model

[Yasushi Yoshida <yyoshida@mug.biglobe.ne.jp>]

Hello,

I would like to run the following nonlinear system of equations:

y(x,t) = a(t)*exp(b*x) / ( 1 + a(t)*exp(b*x) ) + c(t) + u(x,t)

y:mortality rate
x:age
t:year

The parameter b is not time dependant.

I would be very glad about any hints how to do this in Stata 9.

Best regards,

Yasushi Yoshida
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