Daily variations in net gas exchange, chlorophyll a fluorescence and water relations of mature, sun-acclimated grapefruit (Citrus paradisi Macfady.) and orange (Citrus sinensis L. Osbeck) leaves were determined in tree canopies either shaded with 50% shade screens or left unshaded (sunlit). Mean daily maximum photosynthetic photon flux density (PPFD) under shade varied from 500 to 700 micromol ...

This study determined whether the field level concentration of root zone CO2 affects transpiration rate and root water transport in soybean (Glycine max L. Merr.). In an upland field converted from a paddy field, topsoil CO2 during the cropping season rose to 8 kPa of partial pressure after rainfall, whereas O2 dropped only to a minimum of 7 kPa. An elevated root zone CO2 pressure of 6 kPa sign...

[1] Global ocean carbon models and available syntheses of the oceanic CO2 flux suggest that the North Atlantic subpolar gyre (50 N–70 N, 80 W–10 W) is a region of increasing uptake of CO2 from the atmosphere, with the oceanic partial pressure of CO2 (pCO2) increasing more slowly than the atmospheric CO2 over time. Our analysis of available CO2 data shows that, on the contrary, seawater pCO2 has...

Cerebral cortical blood flow was measured in rabbits with the hydrogen clearance technique. The reactivity to CO2, tested by changing the end tidal CO2 (ETCO2) in steps from 2 to 6 volumes %, was highly dependent on the kind of anesthesia, being greatest under halothane and least under nitrous oxide. Reactivity to CO2 in halothane-anesthetized animals also depended on arterial blood pressure, b...

full factorial experimental design (23) for the evaluation of slurry ethylene polymerization in the presence of an industrial ticl4/mgcl2 ziegler-natta catalyst was employed. the following parameters were used as independentvariables: al/ti molar ratio, reaction temperature and hydrogen partial pressure. the total polymerization pressure was 9 bar. catalyst activity, mfi (melt flow index) and m...

Capnography is the monitoring of the partial pressure of alveolar carbon dioxide (CO2) in the respiratory gases. It is a useful noninvasive clinical tool for assessing efficiency and optimizing mechanical ventilation.1 The use of capnography for monitoring surgical patients during anesthesia and in the emergency department to confirm artificial airway placement is well-established and recommend...

We have developed an exercise designed to give students practice calculating arterial O2 content, O2 delivery, physiological dead space, dead space and alveolar ventilation, and alveolar partial pressure of O2 and CO2. The exercise is in the form of a "murder mystery" in which students are required to make these calculations to identify the murderer.

BACKGROUND AND PURPOSE Responsiveness to CO2 is an established test of cerebrovascular reserve capacity. Arterial partial pressure of CO2 (PCO2) and arterial blood pressure (BP) are key parameters for cerebral blood flow. To investigate the interaction between PCO2 and BP, we performed a study with simultaneous measurement of CO2 and BP during CO2 reactivity testing with transcranial Doppler so...