11.   Also, the researchers had to induce relatively high levels of antibody in the mice in order to achieve the desired results.

12.   Although researchers have yet to understand fully what causes reflux, they do know it is not uncommon, and its incidence appears to be rising.

13.   Although the push to computerize is driven by expectations of academic gains, researchers have yet to provide convincing evidence that it will.

14.   American researchers have repeatedly had to go to Europe or Japan to find computers capable of handling their most ambitious climate analyses.

15.   And researchers would also have to prove that it was at least as durable as conventional fiber.

16.   And while they have grown steadily better at predicting El Ninos, researchers have a harder time spotting signs of a developing La Nina.

17.   And the researchers themselves have very different ideas about where to look.

18.   Another major concern is that some researchers have a financial stake in the outcome of a certain drug undergoing clinical trials.

19.   Another common factor in all the wars is that researchers have had a tough time pinning down the cause of the syndromes.

20.   As a result, researchers had to estimate top sustained wind speeds.