BACKGROUND Calculation of total inspiratory resistance (Rtot) for patients on ventilatory support is typically based on measurement of airflow velocity and airway opening pressure during end-inspiratory occlusion by the inspiratory valve in the ventilator. Systematic error is introduced into Rtot measurements because the inspiratory valve closes over a period of time (not instantaneously, so ga...

The metabolic production of heat and high, stable body temperatures characteristic of birds and mammals was a major step in the evolution of vertebrate animals; however, the 1979 paper by Albert Bennett and John Ruben (Bennett and Ruben, 1979) represented a fundamental shift in thinking about the problem of the evolution of endothermy. They argued that endothermy based on thermoregulatory consi...