R help - Sep 2010 - Survival Analysis Daily Time-Varying Covariate....

Help!

I am unsure if I can analyze data from the following experiment.

Fish were placed in a tank at (t=0)
Measurements of Carbon Dioxide were taken each day for 120 days
(t=0,...120)
A few fish were then randomly pulled out of the tank at different days,
killed and examined for the presence of a disease
T= time of examination in days from start (i.e. 85th day), E = 0/1 for
nonevent/event

....

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You need to decide on a mechanistic model.  On the day a fish is
sacrificed, does their risk of disease depend on
	today's CO2 level
	the average CO2 since the start of the experiment
        cumulative CO2 dose
	days over a threshold
	etc
You can examine each of these one by one or in combinations.  It would
be very difficult, however, to ask your program to "find the pattern".

Terry Therneau