11.   The dye allows the researchers to measure the flow of ions, and hence the potential difference, across cell membranes.

12.   The most serious criticism of the imaging has to do with what the researchers are measuring.

13.   The researchers measured an energy difference between the two states of the loop, a sign the current was a quantum superposition and not simply flipping directions.

14.   The researchers measured fitness by having subjects walk on treadmills used by doctors to test cardiovascular health.

15.   The researchers measured the energy consumption of five African women as they walked across a platform carrying loads of progressively heavier weight.

16.   The participants rated their pain, and researchers measured their range of motion.

17.   The researchers were not measuring blood pressure in the right place.

18.   The researchers measured levels of a protein called transcription factor Fos, which is produced by the part of the rat brain that contains the pacemaker.

19.   Working unobtrusively, the researchers measured the psychological consequences.

20.   At the start, the researchers measured the bone density in the wrist, forearm and heel of each woman.