Carbon use efficiency (CUE) is a fundamental parameter for ecological models based on the physiology of microorganisms. CUE determines energy and material flows to higher trophic levels, conversion of plant-produced carbon into microbial products and rates of ecosystem carbon storage. Thermodynamic calculations support a maximum CUE value of ~ 0.60 (CUE max). Kinetic and stoichiometric constrai...

1. Ecological stoichiometry is a conceptual framework that considers how the balance of energy and elements affects and is affected by organisms in the environment. This perspective has seen recent development primarily in marine and freshwater pelagic ecosystems but its widescale application to freshwater benthic ecosystems remains limited. 2. This paper briefly introduces the concept of ecolo...

The stoichiometric recovery and accompanying changes of subsurface atomic structure of Ar ion sputtered, oxygen deficient a-Fe2O3(0001) are studied with X-ray scattering. Although oxygen annealing up to 735 C results in a stoichiometric top surface layer manifested as a (1 · 1) surface structure, the X-ray scattering reveals the existence of a non-stoichiometric phase in the subsurface region. ...

Although the stoichiometry of bulk lead sulfide (PbS) is exactly 1:1, that of quantum dots (QDs) can be considerably different from this crystalline limit. Employing first-principles calculations, we show that the impact of PbS QD stoichiometry on the electronic structure can be enormous, suggesting that control over the overall stoichiometry in the QD will play a critical role for improving th...

2 Abstract. We present the rst results of an ongoing eeort to search for new species in the lunar atmosphere. We discuss our observations in terms of the degree to which atomic metal abundances in the lunar atmosphere are stoichiometric, that is, proportional to surface abundances (as the Na:K ratio is). Na and K are the only atmospheric constituents to have been observed from Earth, but Apollo...

The development of ecological stoichiometry has centered on organisms and their interactions, with less emphasis on the meaning or value of a comprehensive ecosystem stoichiometry at larger scales. Here we develop a conceptual framework that relates internal processes and exogenous factors in spatiallyand temporally-linked ecosystems. This framework emerges from a functional view of ecosystem s...

Lead magnesium niobate—lead titanate (PMN-PT) single crystals have been successfully commercialized in medical ultrasound imaging. The superior properties of PMN-PT crystals over the legacy piezoelectric ceramics lead zirconate titanate (PZT) enabled ultrasound transducers with enhanced imaging (broad bandwidth and improved sensitivity). To obtain high quality and relatively low cost single cry...