"Despite the widely held view that cannabis is benign, this research adds to previous work suggesting otherwise," said Ian Hamilton, a lecturer in mental health at Britain's York University.
There are several “handwaving” maneuvers in the paper, best summarized by this quote from lead author (PhD candidate):
"Yankey said were limitations in the way marijuana use was assessed -- including that researchers could not be sure whether people had used the drug continuously since they first tried it."
A direct quote from the paper shows this:
"Duration of marijuana use was estimated by subtracting participant’s age at marijuana use initiation from the age at the 2005 screen."
Then the conclusion begins with:
Marijuana use, especially prolonged years of use, may increase the risk of hypertension mortality…
I think NNs would work well to solve the bicycle problem with some more data -- maybe a lightweight sensor of some sort on bikes, or a device that could communicate on a public VANET - That would be a safe long term solution, but obviously many years out.
to top it off, there's a westworld spoiler at the bottom