Half distance analog for half life


Active Member
Hi folks. Is there a recognized term for the distance needed for the level of something to drop to one half? For example, the distance down a stream for a contaminant to drop to half that at its source?
Thanks, kat


Less is more. Stay pure. Stay poor.
I was modeling some infectious disease stuff early today and they used some term that i cant recall related to the r-naught in the covid-19 stuff, transmission rate necessary for sustained transmission, which is like in the chain reaction process for nuclear bombs. I dnt think it is critical mass, but perhaps this vague rant will get you closer to your inverted tipping point, half-life, E50 metric. Yeah, check out E50 i used that with dose response once.


Active Member
Thanks. There is also the LD50 for dose response - the dose needed to kill 50% of whatever it is you want to kill. Perhaps it's related to yours.