Earthlearningidea—ideas for the International Year of Planet Earth     

Chris King  Peter Kennett  & Elizabeth Devon 《Geology Today》2008,24(2):68-70

'Earthlearningidea' will be putting up a new idea for learning about the Earth every week during 2008—the International Year of Planet Earth. The ideas are aimed at teacher trainers in science and geography who will be training teachers in the teaching of Earth science—but we hope they will be widely used by classroom teachers who have access to the internet too. A blog runs alongside them aiming to build up a worldwide discussion network of Earth science educators. Help us circulate Earthlearningideas around the globe!  相似文献   

The 6C** sample of steep-spectrum radio sources – I. Radio data, near-infrared imaging and optical spectroscopy     

Maria J. Cruz  Matt J. Jarvis  Katherine M. Blundell  Steve Rawlings  Steve Croft  Hans-Rainer Klöckner  Ross J. McLure  Chris Simpson  Thomas A. Targett  Chris J. Willott 《Monthly notices of the Royal Astronomical Society》2006,373(4):1531-1562

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Patterns of groundwater quality in sandy aquifers under environmental pressure by Marc J M Vissers     

Chris Barber 《Area》2006,38(4):476-476

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The ROSAT–ESO Flux-Limited X-ray (REFLEX) galaxy cluster survey – VI. Constraints on the cosmic matter density from the KL power spectrum     

Peter Schuecker  Luigi Guzzo  Chris A. Collins  Hans Böhringer 《Monthly notices of the Royal Astronomical Society》2002,335(3):807-816

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Weak lensing of the CMB by large-scale structure     

Alexandre Amblard  Chris Vale  Martin White   《New Astronomy》2004,9(8):687-704

Several recent papers have studied lensing of the CMB by large-scale structures, which probes the projected matter distribution from z=10³ to z0. This interest is motivated in part by upcoming high resolution, high sensitivity CMB experiments, such as APEX/SZ, ACT, SPT or Planck, which should be sensitive to lensing. In this paper, we examine the reconstruction of the large-scale dark matter distribution from lensed CMB temperature anisotropies. We go beyond previous work in using numerical simulations to include higher order, non-Gaussian effects and find that the convergence and its power spectrum are biased, with the bias increasing with the angular resolution. We also study the contamination by the kinetic Sunyaev–Zel'dovich signal, which is spectrally indistinguishable from lensed CMB anisotropies, and find that it leads to an overestimate of the convergence. We finish by estimating the sensitivity of the previously cited experiments and find that all of them could detect the lensing effect, but would be biased at around the 10% level.  相似文献   

Stabilization and global climate policy   总被引：1，自引：0，他引：1  

Marcus C. Sarofim  Chris E. Forest  David M. Reiner  John M. Reilly 《Global and Planetary Change》2005,47(2-4):266

Academic and political debates over long-run climate policy often invoke “stabilization” of atmospheric concentrations of greenhouse gases (GHGs), but only rarely are non-CO₂ greenhouse gases addressed explicitly. Even though the majority of short-term climate policies propose trading between gases on a global warming potential (GWP) basis, discussions of whether CO₂ concentrations should be 450, 550, 650 or perhaps as much as 750 ppm leave unstated whether there should be no additional forcing from other GHGs beyond current levels or whether separate concentration targets should be established for each GHG. Here, we use an integrated modeling framework to examine multi-gas stabilization in terms of temperature, economic costs, carbon uptake and other important consequences. We show that there are significant differences in both costs and climate impacts between different “GWP equivalent” policies and demonstrate the importance of non-CO₂ GHG reduction on timescales of up to several centuries.  相似文献   

Topics The Oscar Wilde sculpture     

Chris Stillman 《Geology Today》1999,15(2):72-75

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Invited keynote address: Global change and the polar regions     

Chris Rapley 《Polar research》1999,18(2):117-118

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Towards High-Resolution Habitat Suitability Modeling of Vulnerable Marine Ecosystems in the Deep-Sea: Resolving Terrain Attribute Dependencies     

Anna M. Rengstorf  Anthony Grehan  Chris Yesson  Colin Brown 《Marine Geodesy》2013,36(4):343-361

Recent habitat suitability models used to predict the occurrence of vulnerable marine species, particularly framework building cold-water corals, have identified terrain attributes such as slope and bathymetric position index as important predictive parameters. Due to their scale-dependent nature, a realistic representation of terrain attributes is crucial for the development of reliable habitat suitability models. In this paper, three known coral areas and a noncoral control area off the west coast of Ireland were chosen to assess quantitative and distributional differences between terrain attributes derived from bathymetry grids of varying resolution and information content. Correlation analysis identified consistent changes of terrain attributes as grain size was altered. Response characteristics and dimensions depended on terrain attribute types and the dominant morphological length-scales within the study areas. The subsequent effect on habitat suitability maps was demonstrated by preliminary models generated at different grain sizes. This study demonstrates that high resolution habitat suitability models based on terrain parameters derived from multibeam generated bathymetry are required to detect many of the topographical features found in Irish waters that are associated with coral. This has implications for marine spatial planning in the deep sea. Supplemental materials are available for this article. Go to the publisher's online edition of Marine Geodesy to view the free supplemental file.  相似文献   

Modelling the behaviour of accretion flows in X-ray binaries     

Chris Done  Marek Gierliński  Aya Kubota 《Astronomy and Astrophysics Review》2007,15(1):1-66

We review how the recent increase in X-ray and radio data from black hole and neutron star binaries can be merged together with theoretical advances to give a coherent picture of the physics of the accretion flow in strong gravity. Both long term X-ray light curves, X-ray spectra, the rapid X-ray variability and the radio jet behaviour are consistent with a model where a standard outer accretion disc is truncated at low luminosities, being replaced by a hot, inner flow which also acts as the launching site of the jet. Decreasing the disc truncation radius leads to softer spectra, as well as higher frequencies (including quasi periodic oscillations, QPOs) in the power spectra, and a faster jet. The collapse of the hot flow when the disc reaches the last stable orbit triggers the dramatic decrease in radio flux, as well as giving a qualitative (and often quantitative) explanation for the major hard–soft spectral transition seen in black holes. The neutron stars are also consistent with the same models, but with an additional component due to their surface, giving implicit evidence for the event horizon in black holes. We review claims of observational data which conflict with this picture, but show that these can also be consistent with the truncated disc model. We also review suggested alternative models for the accretion flow which do not involve a truncated disc. The most successful of these converge on a similar geometry, where there is a transition at some radius larger than the last stable orbit between a standard disc and an inner, jet dominated region, with the X-ray source associated with a mildly relativistic outflow, beamed away from the disc. However, the observed uniformity of properties between black holes at different inclinations suggests that even weak beaming of the X-ray emission may be constrained by the data. After collapse of the hot inner flow, the spectrum in black hole systems can be dominated by the disc emission. Its behaviour is consistent with the existence of a last stable orbit, and such data can be used to estimate the black hole spin. By contrast, these systems can also show very different spectra at these high luminosities, in which the disc spectrum (and probably structure) is strongly distorted by Comptonization. The structure of the accretion flow becomes increasingly uncertain as the luminosity approaches (and exceeds) the Eddington luminosity, though there is growing evidence that winds may play an important role. We stress that these high Eddington fraction flows are key to understanding many disparate and currently very active fields such as ULX, Narrow Line Seyfert 1’s, and the growth of the first black holes in the Early Universe.  相似文献