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ybukhman / GCAT

Growth curve analysis tool
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Review all computations and plots involving the baseline #17

Closed ybukhman closed 9 years ago

ybukhman commented 9 years ago

Need to make sure that (estimated) inoculation OD, or its natural log, is consistently used as the baseline value, not parameter b of sigmoid equations.

ybukhman commented 9 years ago

No changes to the code are necessary: • Projected and achieved growth values are already computed using inoc.log.OD • Lag is computed directly from Zwietering's formulas. It is displayed correctly on plots, too. According to Zwietering, "The lag time is defined as the t-axis intercept of the tangent through the inflection point": see equations 7 and 8. Therefore, in GCAT, it is correct to display lag as the intersection between the tangent and the baseline.