Use of CTU method to compute hatching time
FluEgg uses a set of regression equations to compute the egg hatching time for each species. These regressions are based on multiple datasets including the George and Chapman data used for the CTU method. As a result, the estimated hatching time in FE and differ from the hatching time computed using the CTU method (see fig below for GC). Amy George stated that in her lab work she has found the CTU method to produce the most accurate estimate of hatching time for T<23C and the FE regressions for T>23 C. Regardless, we use the CTU method to estimate the hours post fertilization of every egg/larve for RTPT analyses. This can result in a difference in the "phase" (larvae vs. egg) for newly hatched larvae in RTPT sims. The field sample and CTU method may categorize the phase as a larvae, but the particle may be classified as an egg in RTPT sims due to the 0 to 5.5 hr difference in the estimated hatching time. To remain consistent and avoid this issue, we should consider using the CTU method to compute egg hatching time in FluEgg (we already use it to compute the GBI time).