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排序方式: 共有857条查询结果,搜索用时 552 毫秒
721.
Carmen Morales Joaquín Trapero José F. Gómez Verónica Orozco Alvaro Gimenez Stuart Bowyer Jerry Edelstein Eric Korpela Michael Lampton Jeff Cobb 《Astrophysics and Space Science》2001,276(1):141-150
We present here stellar spectra of B stars obtained with the EURD spectrograph, one of the three instruments on board MINISAT-01. EURD is a spectrograph specially designed to detect diffuse radiation in thewavelength range between 350 and 1100 Å with 5 Å spectral resolution. EURD main scientific targets are: the spectrum of interstellar medium,atmospheric airglow, decaying neutrinos, Moon and early type stars. 相似文献
722.
Takuya Fujiyoshi Craig H. Smith Toby J. T. Moore Stuart L. Lumsden David K. Aitken Patrick F. Roche 《Monthly notices of the Royal Astronomical Society》2005,356(3):801-809
We present near-infrared broad-band JHK ' images of the southern massive star-forming region G333.6−0.2. The slope of the K -luminosity function towards the region (0.24 ± 0.01) is considered to be equivalent to that expected for main-sequence stars in the solar neighbourhood. Point sources with their ( H − K ) colour greater than 1 are more likely to be located in extended emission and it is suggested that these objects are physically associated with the H ii region. 相似文献
723.
Near-infrared (JHK) images of the nucleus of the barred spiral galaxy M100 (NGC 4321) have been obtained using a high-bandwidth tip-tilt secondary
and fast guider system on the 3.8 m United Kingdom Infrared Telescope (UKIRT). The resulting images, with a resolution of
0.34″ at K, reveal for the first time a host of compact ‘knots’, which appear to be the result of a recent burst (or bursts) of star
formation. Confirmation of this comes from K-band spectroscopy of these knots with CGS4 on UKIRT, which shows Brγ emission and CO absorption features. A comparison with
starburst evolutionary models suggests ages for these knots of between 17 and 27 Myr, and a stellar population dominated by
late-type supergiants.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
724.
Will J. Percival Daniel Burkey Alan Heavens y Taylor Shaun Cole John A. Peacock Carlton M. Baugh Joss Bland-Hawthorn Terry Bridges Russell Cannon Matthew Colless Chris Collins Warrick Couch Gavin Dalton Roberto De Propris Simon P. Driver George Efstathiou Richard S. Ellis Carlos S. Frenk Karl Glazebrook Carole Jackson Ofer Lahav Ian Lewis Stuart Lumsden Steve Maddox Peder Norberg Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2004,353(4):1201-1218
725.
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727.
Stuart J. Jones 《地学学报》2004,16(3):121-127
An understanding of how drainage patterns respond to tectonics can provide an insight into past deformational events within mountain belts and where sediment flux is supplied to depositional basins. The transverse rivers draining the Spanish Pyrenees show sudden diversions to axial courses and the capture of lateral systems producing large trunk rivers that break through the thrust front at structurally controlled points. The drainage reorganization from the initial regularly spaced pattern in the Late Eocene caused by the growth of thrust‐controlled topography influenced the location of outlets into the Ebro basin. The headward capture and merger of rivers as a result of structural diversion formed two large terminal fan systems during the Oligo‐Miocene along the Pyrenean thrust front. The early structural topographic controls on drainage evolution will have long‐term effects on sedimentation and stratigraphic architecture of foreland basins. This will only be maintained as long as there is tectonic uplift and the river systems strive to re‐attain a regular drainage spacing across the orogenic belt as partly achieved in the Pyrenees. 相似文献
728.
Aaron T. David Pascale A. L. Goertler Stuart H. Munsch Brittany R. Jones Charles A. Simenstad Jason D. Toft Jeffery R. Cordell Emily R. Howe Ayesha Gray Michael P. Hannam William Matsubu Erin E. Morgan 《Estuaries and Coasts》2016,39(5):1491-1504
Compared to benthic and water-column invertebrate assemblages, considerably less is known about terrestrial arthropods inhabiting estuarine wetlands despite their importance to tidal wetland biodiversity and productivity. We also need to know more about how human modification of estuaries, including efforts to restore estuarine wetlands, affects these assemblages. To address this knowledge gap, we assembled data from multiple studies on terrestrial arthropod assemblages from 87 intertidal wetland sites in 13 estuaries along the west coast of North America. Arthropods were sampled between 1998 and 2013 with fallout traps deployed in wetlands for 1 to 3 days at a time. We describe patterns in the abundance and taxonomic composition of terrestrial arthropods and evaluate the relative ability of natural and anthropogenic factors to explain variation in abundance and composition. Arthropod abundance was highly variable. Vegetation assemblage, precipitation, and temperature best explained variation in arthropod abundance, while river discharge, latitude, and developed and agricultural land cover surrounding sampling sites were less important. Arthropod abundance rapidly achieved levels of reference wetlands after the restoration of tidal influence to leveed wetlands, regardless of surrounding land cover. However, arthropod assemblage composition was affected by the amount of developed land cover as well as restoration age. These results suggest that restoration of tidal influence to leveed wetlands can rapidly restore some components of estuarine wetland ecosystems but that recovery of other components will take longer and may depend on the extent of anthropogenic modification in the surrounding landscape. 相似文献
729.
730.
Magmatism at continental passive margins inferred from Ambient‐Noise Phase‐velocity in the Gulf of Aden 下载免费PDF全文
Félicie Korostelev Sylvie Leroy Derek Keir Cornelis Weemstra Lapo Boschi Irene Molinari Abdulhakim Ahmed Graham W. Stuart Frédérique Rolandone Khaled Khanbari Ali Al‐Lazki 《地学学报》2016,28(1):19-26
Non‐volcanic continental passive margins have traditionally been considered to be tectonically and magmatically inactive once continental breakup has occurred and seafloor spreading has commenced. We use ambient‐noise tomography to constrain Rayleigh‐wave phase‐velocity maps beneath the eastern Gulf of Aden (eastern Yemen and southern Oman). In the crust, we image low velocities beneath the Jiza‐Qamar (Yemen) and Ashawq‐Salalah (Oman) basins, likely caused by the presence of partial melt associated with magmatic plumbing systems beneath the rifted margin. Our results provide strong evidence that magma intrusion persists after breakup, modifying the composition and thermal structure of the continental margin. The coincidence between zones of crustal intrusion and steep gradients in lithospheric thinning, as well as with transform faults, suggests that magmatism post‐breakup may be driven by small‐scale convection and enhanced by edge‐driven flow at the juxtaposition of lithosphere of varying thickness and thermal age. 相似文献