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61.
W. I. Clarkson B. Enoch C. A. Haswell A. J. Norton D. J. Christian A. Collier Cameron S. R. Kane K. D. Horne T. A. Lister R. A. Street R. G. West D. M. Wilson N. Evans A. Fitzsimmons C. Hellier S. T. Hodgkin J. Irwin F. P. Keenan J. P. Osborne N. R. Parley D. L. Pollacco R. Ryans I. Skillen P. J. Wheatley 《Monthly notices of the Royal Astronomical Society》2007,381(2):851-864
62.
A. M. S. Smith A. Collier Cameron D. J. Christian W. I. Clarkson B. Enoch A. Evans C. A. Haswell C. Hellier K. Horne J. Irwin S. R. Kane T. A. Lister A. J. Norton N. Parley D. L. Pollacco R. Ryans I. Skillen R. A. Street A. H. M. J. Triaud R. G. West P. J. Wheatley D. M. Wilson 《Monthly notices of the Royal Astronomical Society》2006,373(3):1151-1158
The evolution of the Alfvén turbulence due to three-wave interactions is discussed using kinetic theory for a collisionless, thermal plasma. There are three low-frequency modes, analogous to the three modes of compressible magnetohydrodynamics (MHD). When only Alfvén waves are considered, the known anisotropy of turbulence in incompressible MHD theory is reproduced. Inclusion of a fast mode wave leads to the separation of turbulence into two regimes: small wave numbers where three-wave processes involving a fast mode are dominant, and large wave numbers where the three Alfvén wave process is dominant. Possible application of the anisotropic Alfvén turbulence to the interstellar medium and dissipation of magnetic energy in magnetars are discussed. 相似文献
63.
C. de Rouffignac D. Q. Bowen G. R. Coope D. H. Keen A. M. Lister D. Maddy J. E. Robinson G. A. Sykes M. J. C. Walker 《第四纪科学杂志》1995,10(1):15-31
Pleistocene deposits containing the disarticulated skeleton of a mammoth, and associated faunal and floral remains, were discovered in July 1990 at Upper Strensham, Worcestershire. The environmental evidence from the fauna and flora together with limited geological evidence, indicates that the deposits accumulated within a low energy fluvial environment with a surrounding marsh and restricted tree cover on, or close to, the floodplain. The patchy occurrence of trees in a species-rich grassland is discussed, and the climatic significance of the fauna and flora is considered. The Strensham site lies within the valley of the River Avon, which is known to contain at least five altitudinally distinct river terraces. The deposits at Strensham lie beneath a terraced surface that cannot be accommodated within the existing framework of terrace development in the valley, and evidence is presented which may suggest that these deposits form a previously unrecognised fluvial unit, the Strensham Member of the Avon Valley Formation. Amino-acid age estimates from shells taken from the fossiliferous sediments of the Strensham Member suggest a correlation with Oxygen Isotope Stage 7. This correlation suggests that the temperate deposits at this site should be correlated with the temperate phase recorded at Marsworth, Buckinghamshire and Stoke Goldington in the valley of the Great Ouse. 相似文献
64.
65.
Transfer of atmospheric N deposition on shallow‐soil forested basins on the Canadian Shield to receiving water bodies may be enhanced by rapid preferential flow along the soil–bedrock interface (BR runoff) on basin slopes. Controls on BR runoff, partitioning of event and pre‐event water contributions to this flow, and implications of this partitioning for N fluxes in BR runoff were studied under natural and artificial inputs to an instrumented slope. BR runoff as a fraction of water inputs to the slope increased with antecedent soil wetness and input depth. Event water contributions to BR runoff initially increased with antecedent soil wetness, but then declined at large antecedent soil wetness. Export of applied NH4+ from the slope was maximized when event water contributions containing large NH4+ concentrations dominated BR runoff; however, there was no relationship between the fraction of NO3? application transported in BR runoff and either application input or the event water fraction of that runoff. The applicability of our results to other shallow‐soil areas of the Canadian Shield is limited by artificial N inputs to the slope in excess of natural loads and by low rates of N mineralization and negligible nitrification in the slope's soils. Nevertheless, the study reinforces the need to consider how the hydrologic, geometric and pedologic properties of forest slopes interact with biotic and abiotic soil processes to control N transport and transformation. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
66.
S. R. Kane W. I. Clarkson R. G. West D. M. Wilson D. J. Christian A. Collier Cameron B. Enoch T. A. Lister R. A. Street A. Evans A. Fitzsimmons C. A. Haswell C. Hellier S. T. Hodgkin K. Horne J. Irwin F. P. Keenan A. J. Norton J. Osborne N. R. Parley D. L. Pollacco R. Ryans I. Skillen P. J. Wheatley 《Monthly notices of the Royal Astronomical Society》2008,384(3):1097-1108
The Wide Angle Search for Planets (WASP) survey currently operates two installations, designated SuperWASP-N and SuperWASP-S, located in the Northern and Southern hemispheres, respectively. These installations are designed to provide high time-resolution photometry for the purpose of detecting transiting extrasolar planets, asteroids, and transient events. Here, we present results from a transit-hunting observing campaign using SuperWASP-N covering a right ascension (RA) range of 06h < RA < 16h . This paper represents the fifth and final in the series of transit candidates released from the 2004 observing season. In total, 729 335 stars from 33 fields were monitored with 130 566 having sufficient precision to be scanned for transit signatures. Using a robust transit detection algorithm and selection criteria, six stars were found to have events consistent with the signature of a transiting extrasolar planet based on the photometry, including the known transiting planet XO-1b. These transit candidates are presented here along with discussion of follow-up observations and the expected number of candidates in relation to the overall observing strategy. 相似文献
67.
D. J. Christian N. P. Gibson E. K. Simpson R. A. Street I. Skillen D. Pollacco A. Collier Cameron Y. C. Joshi F. P. Keenan H. C. Stempels C. A. Haswell K. Horne D. R. Anderson S. Bentley F. Bouchy W. I. Clarkson B. Enoch L. Hebb G. Hébrard C. Hellier J. Irwin S. R. Kane T. A. Lister B. Loeillet P. Maxted M. Mayor I. McDonald C. Moutou A. J. Norton N. Parley F. Pont D. Queloz R. Ryans B. Smalley A. M. S. Smith I. Todd S. Udry R. G. West P. J. Wheatley D. M. Wilson 《Monthly notices of the Royal Astronomical Society》2009,392(4):1585-1590
We report the discovery of WASP-10b, a new transiting extrasolar planet (ESP) discovered by the Wide Angle Search for Planets (WASP) Consortium and confirmed using Nordic Optical Telescope FIbre-fed Echelle Spectrograph and SOPHIE radial velocity data. A 3.09-d period, 29 mmag transit depth and 2.36 h duration are derived for WASP-10b using WASP and high-precision photometric observations. Simultaneous fitting to the photometric and radial velocity data using a Markov Chain Monte Carlo procedure leads to a planet radius of 1.28 R J , a mass of 2.96 M J and eccentricity of ≈0.06. WASP-10b is one of the more massive transiting ESPs, and we compare its characteristics to the current sample of transiting ESP, where there is currently little information for masses greater than ≈ 2 M J and non-zero eccentricities. WASP-10's host star, GSC 2752−00114 (USNO-B1.0 1214−0586164) is among the fainter stars in the WASP sample, with V = 12.7 and a spectral type of K5. This result shows promise for future late-type dwarf star surveys. 相似文献
68.
Y. C. Joshi D. Pollacco A. Collier Cameron I. Skillen E. Simpson I. Steele R. A. Street H. C. Stempels D. J. Christian L. Hebb F. Bouchy N. P. Gibson G. Hébrard F. P. Keenan B. Loeillet J. Meaburn C. Moutou B. Smalley I. Todd R. G. West D. R. Anderson S. Bentley B. Enoch C. A. Haswell C. Hellier K. Horne J. Irwin T. A. Lister I. McDonald P. Maxted M. Mayor A. J. Norton N. Parley C. Perrier F. Pont D. Queloz R. Ryans A. M. S. Smith S. Udry P. J. Wheatley D. M. Wilson 《Monthly notices of the Royal Astronomical Society》2009,392(4):1532-1538
We report the discovery of a 7.3 M J exoplanet WASP-14b, one of the most massive transiting exoplanets observed to date. The planet orbits the 10th-magnitude F5V star USNO-B1 11118−0262485 with a period of 2.243 752 d and orbital eccentricity e = 0.09 . A simultaneous fit of the transit light curve and radial velocity measurements yields a planetary mass of 7.3 ± 0.5 M J and a radius of 1.28 ± 0.08 R J . This leads to a mean density of about 4.6 g cm−3 making it the densest transiting exoplanets yet found at an orbital period less than 3 d. We estimate this system to be at a distance of 160 ± 20 pc. Spectral analysis of the host star reveals a temperature of 6475 ± 100 K, log g = 4.07 cm s−2 and v sin i = 4.9 ± 1.0 km s−1 , and also a high lithium abundance, log N (Li) = 2.84 ± 0.05 . The stellar density, effective temperature and rotation rate suggest an age for the system of about 0.5–1.0 Gyr. 相似文献
69.
The island of Ios in the Cyclades, Aegean Sea, Greece, exposes high pressure metamorphic rocks that were subjected to Miocene continental extension subsequent to the Alpine collisional orogeny. The pre-Alpine history of the lower-plate of this Aegean metamorphic core complex involves intrusion of granitoids into metasediments which subsequently underwent Hercynian amphibolite facies metamorphism. During the Alpine orogeny (D2), these rocks were overthrust by the Cyclades blueschist nappe. Later, the lower plate was tectonically exhumed during Oligo-Miocene continental extension and associated plutonism. Final exhumation occurred as a result of the operation of a south-directed, crustal-scale shear zone and low-angle normal faults. This study shows that the Ios core complex reflects an intrinsic relationship between early thrusting and later extensional tectonism. Basement rocks have been exhumed from beneath the nappes that originally overrode them. 相似文献
70.
The simulation of fabric development during plastic deformation and its application to quartzite: the influence of deformation history 总被引:1,自引:0,他引:1
The effect of deformation history on the development of crystallographic preferred orientation in quartzities has been simulated using a computer program based on the Taylor-Bishop-Hill analysis. Model quartzities with different combinations of glide systems have been subjected to various coaxial and non-coaxial deformation histories. It is possible to obtain information from the fabrics that develop during simple histories; for example, the location of the axis of extension is generally associated with a pole free area on a c-axis plot, and progressive axial shortening, plane strain and axial shortening produce characteristic fabrics. In progressive simple shear the fabric skeleton becomes asymmetric relative to the sense of shear and a-axes preferentially align in the flow plane parallel to the flow direction. However, this example illustrates that the fabric orientation and characteristics are controlled by the kinematic framework and bear only an indirect relationship to the finite strain accumulated to that point in the history.The imprint of the closing stages of deformation limits to some degree the use of crystallographic fabrics as a tool for structural geologists, but in favourable circumstances data can be obtained concerning characteristics of the deformation history, on the scale of the hand-specimen, for the last part of this history. 相似文献