Andrew R. Smith

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Rising atmospheric [CO2 ], ca , is expected to affect stomatal regulation of leaf gas-exchange of woody plants, thus influencing energy fluxes as well as carbon (C), water, and nutrient cycling of forests. Researchers have proposed various strategies for stomatal regulation of leaf gas-exchange that include maintaining a constant leaf internal [CO2 ], ci ,(More)
We measured the effect of elevated atmospheric CO2 on atmospheric nitrogen (N2) fixation in the tree species Alnus glutinosa growing in monoculture or in mixture with the non-N2-fixing tree species Betula pendula and Fagus sylvatica. We addressed the hypotheses that (1) N2 fixation in A. glutinosa will increase in response to increased atmospheric CO2(More)
Cryogenic air separation technology has been successfully employed for many years to supply oxygen for the gasification of a wide range of hydrocarbon feedstocks to generate synthesis gas for the production of fuels, chemicals and other valuable products. Examples include the conversion of liquid and solid refinery waste streams into hydrogen for use within(More)
Hydrogen etching of 6H-and 4H-SiC(0001) surfaces is studied. The as-polished substrates contain a large number of scratches arising from the polishing process which are eliminated by hydrogen etching. Etching is carried out in a flow of hydrogen gas at atmospheric pressure and temperatures around 1600-1700 C attained on a tantalum strip heater. Post-etching(More)
Anthropogenic activity has increased the level of atmospheric CO2, which is driving an increase of global temperatures and associated changes in precipitation patterns. At Northern latitudes, one of the likely consequences of global warming is increased precipitation and air humidity. In this work, the effects of both elevated atmospheric CO2 and increased(More)
Ecosystems may exhibit alternative stable states (ASS) in response to environmental change. Modelling and observational data broadly support the theory of ASS, however evidence from manipulation experiments supporting this theory is limited. Here, we provide long-term manipulation and observation data supporting the existence of drought induced alternative(More)
Reconstructions of GaN͑0001͒ and ͑0001 ¯ ͒ surfaces are studied by scanning tunneling microscopy and spectroscopy, by electron diffraction, by Auger electron spectroscopy, and using first-principles theory. Attention is focused on Ga-rich reconstructions for each surface, which are found to have a metallic character involving significant overlap between Ga(More)
Biogeosciences Discussions This discussion paper is/has been under review for the journal Biogeosciences (BG). Please refer to the corresponding final paper in BG if available. Abstract As a key component of the carbon cycle, soil CO 2 efflux (SCE) is being increasingly studied to improve our mechanistic understanding of this important carbon flux.(More)
CUORE is a proposed tightly packed array of 1000 T eO2 bolometers, each being a cube 5 cm on a side with a mass of 750 gms. The array consists of 25 vertical towers, arranged in a square, of 5 towers by 5 towers, each containing 10 layers of 4 crystals. The design of the detector is optimized for ultralow-background searches for neutrinoless double beta(More)
A surprisingly large concentration of radioactive 7 Be was observed in the upper atmosphere at altitudes above 320 km on the LDEF satellite that was recovered in January 1990. We report on follow-up experiments on Russian spacecraft at altitudes of 167 to 370 km during the period of 1996 to 1999, specifically designed to measure 7 Be concentrations in low(More)