http://hdl.handle.net/1957/494 2013-05-16T10:24:16Z http://hdl.handle.net/1957/38184 Silica sol‐gel encapsulation of cyanobacteria: lessons for academic and applied research Dickson, David J.; Ely, Roger L. Cyanobacteria inhabit nearly every ecosystem on earth, play a vital role in nutrient cycling, and are useful as model organisms for fundamental research in photosynthesis and carbon and nitrogen fixation. In addition, they are important for several established biotechnologies for producing food additives, nutritional and pharmaceutical compounds, and pigments, as well as emerging biotechnologies for biofuels and other products. Encapsulation of living cyanobacteria into a porous, silica gel matrix is a recent approach that may dramatically improve the efficiency of certain production processes by retaining the biomass within the reactor and modifying cellular metabolism in helpful ways. Although encapsulation has been explored empirically in the last two decades for a variety of cell types, many challenges remain to achieving optimal encapsulation of cyanobacteria in silica gel. Recent evidence with Synechocystis sp. PCC 6803, for example, suggests that several unknown or uncharacterized proteins are dramatically up‐regulated as a result of encapsulation. Also, additives commonly used to ease stresses of encapsulating living cells, such as glycerol, have detrimental impacts on photosynthesis in cyanobacteria. This mini‐review is intended to address the current status of research on silica sol‐gel encapsulation of cyanobacteria and research areas that may further the development of this approach for biotechnology applications. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by Springer and can be found at: http://link.springer.com/journal/253. 2013-03-01T00:00:00Z http://hdl.handle.net/1957/37951 The Effect of Scale on the Applicability of Taylor’s Frozen Turbulence Hypothesis in the Atmospheric Boundary Layer Higgins, Chad W.; Froidevaux, Martin; Simeonov, Valentin; Vercauteren, Nikki; Barry, Caitlin; Parlange, Marc B. Taylor’s frozen turbulence hypothesis is the central assumption invoked in most experiments designed to investigate turbulence physics with time resolving sensors. It is also frequently used in theoretical discussions when linking Lagrangian to Eulerian flow formalisms. In this work we seek to quantify the effectiveness of Taylor’s hypothesis on the field scale using water vapour as a passive tracer. A horizontally orientated Raman lidar is used to capture the humidity field in space and time above an agricultural region in Switzerland. High resolution wind speed and direction measurements are conducted simultaneously allowing for a direct test of Taylor’s hypothesis at the field scale. Through a wavelet decomposition of the lidar humidity measurements we show that the scale of turbulent motions has a strong influence on the applicability of Taylor’s hypothesis. This dependency on scale is explained through the use of dimensional analysis.We identify a ‘persistency scale’ that can be used to quantify the effectiveness of Taylor’s hypothesis, and present the accuracy of the hypothesis as a function of this non-dimensional length scale. These results are further investigated and verified through the use of large-eddy simulations. This is the publisher’s final pdf. The published article is copyrighted by Springer and can be found at: http://www.springer.com/?SGWID=0-102-0-0-0. 2012-02-10T00:00:00Z http://hdl.handle.net/1957/37921 Effects of vegetation canopy density and bank angle on near-bank patterns of turbulence and Reynolds stresses Czarnomski, Nicole M.; Tullos, Desiree D.; Thomas, Robert E.; Simon, Andrew Vegetation growing on the surface of a streambank has been shown to alter the shear stresses applied to the boundary, but basic questions remain regarding the influence of vegetation and streambank configurations on near-bank hydraulics. In the present study, Froude-scaled flume experiments were used to investigate how changes in vegetation density (ratio of frontal area to channel area, including both stems and leaves) and bank surface angle influence near-bank turbulence intensities (RMS[subscript u,v,w]) and Reynolds stresses (τ[subscript uv] and τ[subscript uw]) estimated using velocities obtained with an acoustic Doppler velocimeter positioned beneath the canopy. Results illustrate how, with increasing vegetation density, turbulence intensities and Reynolds stresses decreased along the sloped bank surface but increased at the base of the slope and within the main channel. The steeper bank angle resulted in greater vertical stresses on the bank surface than the shallower angle, but lateral momentum exchange was larger than vertical exchange along the base of the slope, regardless of bank angle. Leaves were an important influence on near-bank turbulence intensities and Reynolds stresses, while the influence of bank slope was small relative to the influence of vegetation density. This is the author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Society of Civil Engineers and can be found at: ASCE Civil Engineering Database(http://cedb.asce.org). 2012-11-01T00:00:00Z http://hdl.handle.net/1957/36899 Taking the Temperature of Ecological Systems With Fiber Optics Selker, John No abstract available. The published article is copyrighted by Wiley-Blackwell and can be found at: http://onlinelibrary.wiley.com/. 2008-05-13T00:00:00Z