sample treatment intensity 1 alpha 550 1 gamma 567 1 combo 602 1 none 525 2 alpha 564 2 gamma 572 2 combo 599 2 none 530 3 alpha 543 3 gamma 562 3 combo 575 3 none 499 4 alpha 1365 4 gamma 1380 4 combo 1400 4 none 1325