Not all of the San Francisco taxis have credit card machines, so it's best to have cash available to pay for your ride. If you don't have cash and need to use a credit card, confirm with the driver before you get in that they have a credit card machine and that it's working. M...
In summary, we find that highly oxidized organic compounds play a role in atmospheric particle nucleation comparable to that of sulfuric acid; together with a suitable stabilizing agent, each has sufficiently low volatility to form new particles in the lower atmosphere at vapour concentrations near 10...