نتایج جستجو برای: co2
تعداد نتایج: 70752 فیلتر نتایج به سال:
We conducted regional cortical blood flow studies using the xenon-133 clearance technique on 12 volunteers during the administration of 25% and 50% N2O and during baseline conditions (breathing room air or 100% O2). Global cortical blood flow was very highly significantly increased above baseline measures in all subjects by 50% N2O (mean increase 37% above 100% O2 condition). A smaller but stil...
Plant mitochondrial group II introns do not all possess hallmark ribozymic features such as the bulged adenosine involved in lariat formation. To gain insight into their splicing pathways, we have examined the physical form of excised introns in germinating wheat embryos. Using RT-PCR and cRT-PCR, we observed conventional lariats consistent with a two-step transesterification pathway for intron...
Acute hypercapnia may develop during periodic breathing from an imbalance between abnormal ventilatory patterns during apnea and/or hypopnea and compensatory ventilatory response in the interevent periods. However, transition of this acute hypercapnia into chronic sustained hypercapnia during wakefulness remains unexplained. We hypothesized that respiratory-renal interactions would play a criti...
The single ion magnetic properties of Co(ii) are affected by the details of the coordination geometry of the ion. Here we show that a geometry close to trigonal prismatic which arises when the ligand 6,6'-((1Z)-((piperazine-1,4-diylbis(propane-3,1-diyl))bis(azanylylidene))bis(methanylylidene))bis(2-methoxyphenol) coordinates to Co(ii) does indeed lead to enhanced single-ion behaviour as has pre...
This paper presents an experimental investigation of the individual willingness to pay (WTP) for green electricity. The experimental design comprises a public-choice scenario and a individual-choice scenario. It involves three different payment vehicles for the public promotion of renewables: direct tax, indirect tax, and CO2 tax. We test for the extent of freeriding, the impact of different pa...
Plant species vary in response to atmospheric CO2 concentration due to differences in physiology, morphology, phenology, and symbiotic relationships. These differences make it very difficult to predict how plant communities will respond to elevated CO2. Such information is critical to furthering our understanding of community and ecosystem responses to global climate change. To determine how a ...
To model the effect of increasing atmospheric CO2 on semi-arid grasslands, the gas exchange responses of leaves to seasonal changes in soil water, and how they are modified by CO2, must be understood for C3 and C4 species that grow in the same area. In this study, open-top chambers were used to investigate the photosynthetic and stomatal responses of Pascopyrum smithii (C3) and Bouteloua gracil...
Two alternative mechanisms have been proposed for tubular reabsorption of bicarbonate: (a) H+ secretion and CO2 reabsorption and (b) direct reabsorption of HCO-3. In an attempt to differentiate between the two mechanisms, the present study utilized the natural abundance of stable carbon isotopes (13C, 12C) in the urinary total CO2. This novel methodology used mass spectrometric analysis of 13C/...
This work analyses the carbon dioxide (CO2) capture system operation within the Electric Reliability Council of Texas (ERCOT) and Great Britain (GB) electric grids using a previously developed first-order hourly electricity dispatch and pricing model. The grids are compared in their 2006 configuration with the addition of coal-based CO2 capture retrofits and emissions penalties from 0 to 100 US...
Carbon Capture and Storage (CCS) is a method to reduce anthropogenic greenhouse gas emissions thereby mitigating global warming. In CCS, carbon dioxide (CO2) is captured from fossil fuel-fired power plants or other large point-source emitters, purified, compressed and injected deep underground into subsurface formations at depths of or greater than 800m. At such depths CO2 is in a supercritical...
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