It was concluded that presence ofcannabinoids in urine or blood is not unequivocal proof of active cannabissmoking. Giardino 25 26 found THC-acid levels of up to 30-50ng/ml from passive-exposed subjects, and recommended a threshold of 65ng/ml to differentiatebetween active and passive smoking of cannabis.ticht & Kaferstein 20 estimated that the blood THC concentrationsproduced in a 70kg person smoking 15mg THC would peak at 7-8 minutes,after 30 minutes between 14-42ng/ml, and at 60 minutes between 7.5-14ng/ml.3.3 McBay 21 compared THC and THC-COOH levels in a study involving smokedmarijuana cigarettes.
Calculation Using An ovulation Calendar: 1  The first day of a period is considered as day 1. 2  Usually on day 14, the egg is released and is waiting for the sperm to fertilize it. 3  The egg has a lifespan of just 12 to 24 hours whereas a sperm can last for about 72 hours in a woman.
The â14th-dayâ thinking appears to come from either taking the average of when all women ovulate or from just dividing the 28-day cycle in half. This is not an accurate way to calculate ovulation because many women do NOT ovulate on the 14th day of their cycle. The day of ovulation differs from woman to woman and can even be different from month to month for an individual woman. For a woman with a 28-day cycle, the window of ovulation is day 11 through day 21 of your cycle. Ovulation could occur on any one day during this window.