In an experiment reported in the scientific literature, male cockroaches were made to run at different speeds on a miniature treadmill while their O2 consumption was measured by noting the decrease in its partial pressure in the experimental chamber. For example, a cockroach weighing 52 g and running for 1 hour at an average speed of 0.08 km/hr consumed 5.46 g of O2. Assuming that the volume of the experimental chamber was 3.80 L and that the temperature was 24.1o C, what was the change in the partial pressure of O2 in the chamber?