“Stone Decay Hazards”     

Siegfried Siegesmund  Heather Viles  Thomas Weiss 《Environmental Geology》2004,46(3-4):303-304

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Calcification rate and temperature effects on Sr partitioning in coccoliths of multiple species of coccolithophorids in culture     

Heather M. Stoll  Christine M. Klaas  Ian Probert  Jorge Ruiz Encinar  J. Ignacio Garcia Alonso   《Global and Planetary Change》2002,34(3-4)

Five common placolith-bearing coccolithophorid algae—Gephyrocapsa oceanica, Coccolithus pelagicus, Calcidiscus leptoporus, Umbilicosphaera sibogae (var. sibogae and var. foliosa), and Emiliania huxleyi—were cultured to investigate controls on Sr partitioning in coccolith calcite. For identical temperature and media composition, Sr partitioning varies by more than 30% in exponential phase cultures of the five species and is linearly related to rates of calcite production/cell (ρ=0.91). Exponential phase culture experiments with three strains of C. leptoporus and six strains of G. oceanica at varying temperatures show variations in Sr partitioning of 20% and 30%, respectively. With C. leptoporus, Sr partitioning is equally correlated with temperature and calcification rate (ρ=0.8), which themselves are highly correlated; the slope of the relationship between D_Sr and calcification rate is comparable to that observed in all species at constant temperature. However, in G. oceanica, increased temperature appears to enhance Sr incorporation by up to 2% to 1.6% °C⁻¹ in the range of 15 to 30 °C. The strong influence of calcification rate on Sr partitioning may be useful for inferring past variations in coccolithophorid productivity from Sr partitioning in coccolith sediments if the influence of temperature on Sr partitioning can be resolved. Because the relationship between calcite production and Sr partitioning is linear, a proportional change in calcification should be expressed much more strongly in the Sr/Ca ratio of large species with rapid calcite production than in smaller species, which produce calcite more slowly. Consequently, it may be possible to separate temperature and calcification influences on coccolith Sr/Ca by separately analyzing Sr/Ca in species that produce calcite rapidly and those that produce calcite slowly, if both undergo comparable relative changes in calcification rates.  相似文献   

The radial velocity dispersion profile of the Galactic halo: constraining the density profile of the dark halo of the Milky Way     

Giuseppina Battaglia  Amina Helmi  Heather Morrison  Paul Harding  Edward W. Olszewski  Mario Mateo  Kenneth C. Freeman  John Norris  Stephen A. Shectman 《Monthly notices of the Royal Astronomical Society》2005,364(2):433-442

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Quantifying Striped Bass (<Emphasis Type="Italic">Morone saxatilis</Emphasis>) Dependence on Saltmarsh-Derived Productivity Using Stable Isotope Analysis     

Henry?K.?Baker  James?A.?NelsonEmail author  Heather?M.?Leslie 《Estuaries and Coasts》2016,39(5):1537-1542

Each winter, populations of striped bass (Morone saxatilis) migrate north from the coastal mid-Atlantic region of the US to the coastal waters of New England. During this migration, striped bass spend significant time in estuaries and saltmarshes, presumably to forage. However, the extent to which saltmarsh productivity supports striped bass remains unresolved. We used a three-isotope Bayesian mixing model to determine the relative contribution of three primary producers [C4 saltmarsh cordgrass (Spartina spp.), phytoplankton, and benthic diatoms] to striped bass tissue. Phytoplankton (51 % contribution) and Spartina-derived sources (44 % contribution) are the primary sources of production to striped bass, while benthic diatoms made a relatively small contribution (5 %). Our results highlight the importance of saltmarshes to striped bass by showing that primary producers unique to saltmarsh ecosystems support a large proportion of striped bass production.  相似文献   

Climate change impacts on ecosystems and ecosystem services in the United States: process and prospects for sustained assessment     

Nancy B. Grimm  Peter Groffman  Michelle Staudinger  Heather Tallis 《Climatic change》2016,135(1):97-109

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Seismic site characterization with shear wave (SH) reflection and refraction methods     

Hunter  James A.  Crow  Heather L.  Stephenson  William J.  Pugin  André J.-M.  Williams  Robert A.  Harris  James B.  Odum  Jack K.  Woolery  Edward W. 《Journal of Seismology》2022,26(4):631-652

Journal of Seismology - Reflection and critically refracted seismic methods use traveltime measurements of body waves propagating between a source and a series of receivers on the ground surface to...  相似文献   

Climate change impacts on freshwater fish,coral reefs,and related ecosystem services in the United States     

Diana Lane  Russell Jones  David Mills  Cameron Wobus  Richard C. Ready  Robert W. Buddemeier  Eric English  Jeremy Martinich  Kate Shouse  Heather Hosterman 《Climatic change》2015,131(1):143-157

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Erratum to: Climate change impacts on freshwater fish,coral reefs,and related ecosystem services in the United States     

Diana Lane  Russell Jones  David Mills  Cameron Wobus  Richard C. Ready  Robert W. Buddemeier  Eric English  Jeremy Martinich  Kate Shouse  Heather Hosterman 《Climatic change》2015,131(1):159-161

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Improving Bayesian analysis for LISA Pathfinder using an efficient Markov Chain Monte Carlo method     

Luigi Ferraioli  Edward K. Porter  Michele Armano  Heather Audley  Giuseppe Congedo  Ingo Diepholz  Ferran Gibert  Martin Hewitson  Mauro Hueller  Nikolaos Karnesis  Natalia Korsakova  Miquel Nofrarias  Eric Plagnol  Stefano Vitale 《Experimental Astronomy》2014,37(1):109-125

We present a parameter estimation procedure based on a Bayesian framework by applying a Markov Chain Monte Carlo algorithm to the calibration of the dynamical parameters of the LISA Pathfinder satellite. The method is based on the Metropolis-Hastings algorithm and a two-stage annealing treatment in order to ensure an effective exploration of the parameter space at the beginning of the chain. We compare two versions of the algorithm with an application to a LISA Pathfinder data analysis problem. The two algorithms share the same heating strategy but with one moving in coordinate directions using proposals from a multivariate Gaussian distribution, while the other uses the natural logarithm of some parameters and proposes jumps in the eigen-space of the Fisher Information matrix. The algorithm proposing jumps in the eigen-space of the Fisher Information matrix demonstrates a higher acceptance rate and a slightly better convergence towards the equilibrium parameter distributions in the application to LISA Pathfinder data. For this experiment, we return parameter values that are all within ～1σ of the injected values. When we analyse the accuracy of our parameter estimation in terms of the effect they have on the force-per-unit of mass noise, we find that the induced errors are three orders of magnitude less than the expected experimental uncertainty in the power spectral density.  相似文献   

Controls on spatial variability in snow accumulation on glaciers in the Southern Alps,New Zealand; as revealed by crevasse stratigraphy     

Heather Purdie  Brian Anderson  Wendy Lawson  Andrew Mackintosh 《水文研究》2011,25(1):54-63

Net accumulation measurements from two glaciers located on opposite sides of the New Zealand Southern Alps were used to explore processes controlling spatial variability. The degree of variability, as measured by the spatial variogram, differed in each of the three successive years, but the lowest variance occurred on both glaciers in March 2008, after a hot and dry summer. Strong relationships between net accumulation and elevation within the accumulation area were only found on Franz Josef Glacier (FJG), despite this being the primary control used in glacier mass balance modelling. Interaction between wind and topography was found to be important to the distribution of net accumulation on both glaciers. The crevasse stratigraphy method is an ideal way to gain good spatial coverage of net accumulation, and particularly suited to glaciers with high annual precipitation. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献