11.   The researchers initially assumed there was some sort of mix-up with the earlier cultures or contamination.

12.   This may be an underestimate, because the researchers assumed balloons survive for only one year.

13.   Until now, scientists said researchers had assumed that these varieties, some of which are only grown by subsistence farmers in remote areas, were pristine.

14.   But he said the researchers assumed most people continued their regular habits during the follow-up.

15.   Historically, medical researchers have assumed that, other than their reproductive systems, men and women basically reacted the same way to drugs.

16.   Researchers had assumed that sleeker, more athletic birds would have the best chance of survival.

17.   The researchers assumed that technical problems, including possible trouble transporting the fragile protein, messed up their experiments.