corrcoef([dz,dy-dn,dy,dn]):

  for data in sfig3a.dat

    1.0000    0.7728    0.2779   -0.1241
    0.7728    1.0000    0.5942    0.1288
    0.2779    0.5942    1.0000    0.8741
   -0.1241    0.1288    0.8741    1.0000

  for data in sfig3b.dat

    1.0000    0.8920    0.8421    0.4269
    0.8920    1.0000    0.5340   -0.0065
    0.8421    0.5340    1.0000    0.8420
    0.4269   -0.0065    0.8420    1.0000