Samples came from six major metropolitan areas: San Francisco, Boston, Minneapolis, Los Angeles, New York City, and Seattle. That is essentially most of America's workforce. A study published on Tuesday in PLoS Medicine suggests that boosting vitamin D levels with supplements would not help. Pool testing allows scientists to test samples more efficiently, analyzing many samples at once. To test samples more efficiently, the researchers used a technique called 'pooling.'
>Samples came from six major error-filled districts.
( z0 come :ARG1 ( z1 thing :ARG1-of ( z2 sample ) ) :ARG3 ( z3 district :quant 6 :ARG1-of ( z4 fill :ARG2 ( z5 error ) ) :ARG1-of ( z6 major ) ) )
(z0 / come-01
    :ARG1 (z1 / thing
              :ARG1-of (z2 / sample-01))
    :ARG3 (z3 / district
              :quant 6
              :ARG1-of (z4 / fill-01
                           :ARG2 (z5 / error))
              :ARG1-of (z6 / major-02)))
>Samples came from six major error - filled districts .
z1 :ARG1-of z2
z0 :ARG1 z1
z4 :ARG2 z5
z3 :ARG1-of z4
z3 :ARG1-of z6
z3 :quant 0
z0 :ARG3 z3