نتایج جستجو برای: net flux

تعداد نتایج: 181425  

Journal: :Applied and environmental microbiology 2002
Lana Shabala Birgitte Budde Tom Ross Henrik Siegumfeldt Mogens Jakobsen Tom McMeekin

Fluorescence ratio imaging microscopy and microelectrode ion flux estimation techniques were combined to study mechanisms of pH homeostasis in Listeria monocytogenes subjected to acid stress at different levels of glucose availability. This novel combination provided a unique opportunity to measure changes in H(+) at either side of the bacterial membrane in real time and therefore to evaluate t...

2010
L. Li Q. Yu L. Ma L. R. Ahuja

Plant water status is a key factor impacting crop growth and agricultural watermanagement. Cropwater stress may alter canopy temperature, the energy balance, transpiration, photosynthesis, canopy water use efficiency, and crop yield. The objective of this study was to calculate the Crop Water Stress Index (CWSI) from canopy temperature and energy balance measurements and evaluate the utility of...

Journal: :Ecological applications : a publication of the Ecological Society of America 2011
L Spadavecchia M Williams B E Law

We present an analysis of the relative magnitude and contribution of parameter and driver uncertainty to the confidence intervals on estimates of net carbon fluxes. Model parameters may be difficult or impractical to measure, while driver fields are rarely complete, with data gaps due to sensor failure and sparse observational networks. Parameters are generally derived through some optimization...

Journal: :فیزیک زمین و فضا 0
نیلوفر اکبری مقدم دانش آموخته کارشناسی ارشد هواشناسی، گروه فیزیک فضا، مؤسسة ژئوفیزیک دانشگاه تهران، ایران عباسعلی علی اکبری بیدختی استاد، گروه فیزیک فضا، مؤسسة ژئوفیزیک دانشگاه تهران، ایران پرویز ایران نژاد دانشیار، گروه فیزیک فضا، مؤسسة ژئوفیزیک دانشگاه تهران، ایران

in the nighttime, drainage flow occurs along the basin sideslope and advects cold air to the boundary layer over the basin bottom (bbl), intensifying the cooling rate of the layer. a nocturnal cold air lake develops in the basin, attaining a depth nearly equal to the topographical depth of the basin. heat budget analysis of the whole basin surface shows that net radiative flux closely balances ...

Journal: :Gut 1977
W D Rees J Rhodes M H Wheeler E M Meek B Williams R G Newcombe

The net ionic fluxes of H+ and Na+ were examined in Heidenhain pouches during damage with sodium taurocholate solution. The increase in ionic flux which occurred with taurocholate could be prevented in animals given H1 and H2 histamine antagonists in combination. The results suggest that histamine mediates changes in the transmucosal ionic flux produced by bile acid.

2012
Georg Wohlfahrt Katja Klumpp Jean-François Soussana

In this chapter we first provide a historic overview of – and outline some of the peculiarities associated with – grassland eddy covariance flux measurements, elaborate on the additional terms that need to be quantified when estimating the grassland net ecosystem carbon balance and finally discuss some of the challenges associated with upcoming nitrous oxide and methane flux measurements in man...

2007
Z. Yang R. A. Washenfelder G. Keppel-Aleks N. Y. Krakauer J. T. Randerson P. P. Tans C. Sweeney P. O. Wennberg

[1] Observations of the column-averaged dry molar mixing ratio of CO2 above both Park Falls, Wisconsin and Kitt Peak, Arizona, together with partial columns derived from aircraft profiles over Eurasia and North America are used to estimate the seasonal integral of net ecosystem exchange (NEE) between the atmosphere and the terrestrial biosphere in the Northern Hemisphere. We find that NEE is 25...

2008
Kevin R. Gurney David Baker Peter Rayner Scott Denning

[1] Interannually varying net carbon exchange fluxes from the TransCom 3 Level 2 Atmospheric Inversion Intercomparison Experiment are presented for the 1980 to 2005 time period. The fluxes represent the model mean, net carbon exchange for 11 land and 11 ocean regions after subtraction of fossil fuel CO2 emissions. Both aggregated regional totals and the individual regional estimates are accompa...

2009
Norman E. Peters Brent T. Aulenbach

Short-term weathering rates (chemical denudation) of primary weathering products were derived from an analysis of fluxes in precipitation and streamwater. Rainfall, streamflow (runoff), and related water quality have been monitored at the Panola Mountain Research Watershed (PMRW) since 1985. Regression relations of stream solute concentration of major ions including weathering products [sodium ...

Journal: :The Journal of General Physiology 1987
J S Adorante P M Cala

Exposure of Amphiuma red blood cells to millimolar concentrations of N-ethylmaleimide (NEM) resulted in net K loss. In order to determine whether net K loss was conductive or was by electroneutral K/H exchange or KCl cotransport, studies were performed evaluating K flux in terms of the thermodynamic forces to which K flux by the above pathways should couple. The direction and magnitude of the N...

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