Testing and application of a model for snow redistribution (Snow_Blow) in the Ellsworth Mountains, Antarctica

Wind-driven snow redistribution can increase the spatial heterogeneity of snow accumulation on ice caps and ice sheets, and may prove crucial for the initiation and survival of glaciers in areas of marginal glaciation. We present a snowdrift model (Snow_Blow), which extends and improves the model of Purves et al. (1999). The model calculates spatial variations in relative snow accumulation that result from variations in topography, using a digital elevation model (DEM) and wind direction as inputs. Improvements include snow redistribution using a flux routing algorithm, DEM resolution independence and the addition of a slope curvature component. This paper tests Snow_Blow in Antarctica (a modern environment) and reveals its potential for application in palaeo-environmental settings, where input meteorological data are unavailable and difficult to estimate. Specifically, Snow_Blow is applied to the Ellsworth Mountains in West Antarctica where ablation is considered to be predominantly related to wind erosion processes. We find that Snow_Blow is able to replicate well the existing distribution of accumulating snow and snow erosion as recorded in and around Blue Ice Areas. Lastly, a variety of model parameters are tested, including depositional distance and erosion vs wind speed, to provide the most likely input parameters for palaeo-environmental reconstructions

Minimalism and Truth-Aptness

Version of Record: Mind 103, 1994, 287-30

Field samples with covariates

Field samples from Kansas of Rhopalosiphum padi, Schizaphis graminum, Sitobion avena, and Barley yellow dwarf virus with covariates

all covariates for predictions

Spatio-temporal covariates used to make predictive maps across the state of Kansas

Simultaneous Determination of Absolute Configuration and Quantity of Lipopeptides Using Chiral Liquid Chromatography/Mass Spectrometry and Diastereomeric Internal Standards

Lipopeptides promote innate immune response and are related to disease pathology. To investigate the newly emerging roles of lipopeptides, accurate measurements of stereoisomers with multiple chiral centers are essential yet challenging. This work uses (3<i>R</i>)- and (3<i>S</i>)-(15-methyl-3-((13-methyltetradecanoyl)­oxy)­hexadecanoyl)­glycyl-l-serine, abbreviated as l-serine-(<i>R</i>+<i>S</i>)-Lipid 654, to develop a method that combines chiral liquid chromatography, a diastereomeric mixture of isotopically labeled internal standards, and multiple reaction monitoring mass spectrometry. The new method allows for simultaneously determining the absolute configuration and quantity of stereoisomers of bacteria-derived lipopeptides. Total lipid extracts of nine evaluated bacteria strains had different amounts, but only the (<i>R</i>)-isoform of l-serine-Lipid 654. The developed method also allowed for the first quantitative analysis of hydrolysis of a nonphospholipid as a novel substrate of honey bee venom phospholipase A2

<i>Holacanthus tricolor</i>, 19.3 mm SL, juvenile color pattern, photo by JT Williams.

<p><i>Holacanthus tricolor</i>, 19.3 mm SL, juvenile color pattern, photo by JT Williams.</p

<i>Brotula barbata</i>, 628 mm TL, photo by W Toller.

<p><i>Brotula barbata</i>, 628 mm TL, photo by W Toller.</p

<i>Gillellus uranidea</i>, 27.7 mm SL, photo by JT Williams.

<p><i>Gillellus uranidea</i>, 27.7 mm SL, photo by JT Williams.</p

<i>Epinephelus flavolimbatus</i>, 652 mm SL, photo by W Toller.

<p><i>Epinephelus flavolimbatus</i>, 652 mm SL, photo by W Toller.</p

<i>Scorpaena grandicornis</i>, 65.1 mm SL, photo by JT Williams.

<p><i>Scorpaena grandicornis</i>, 65.1 mm SL, photo by JT Williams.</p