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百度 境外当地体验类产品的当天预订量占比增长了10%，境内则增长了13%。As a service to the community, this article is available for free.
昌图县畜牧业价格监测和肉牛生产监测实现两个全国第一
Abstract
Lobate features abutting massifs and escarpments in the middle latitudes of Mars have been recognized in images for decades, but their true nature has been controversial, with hypotheses of origin such as ice-lubricated debris flows or glaciers covered by a layer of surface debris. These models imply an ice content ranging from minor and interstitial to massive and relatively pure. Soundings of these deposits in the eastern Hellas region by the Shallow Radar on the Mars Reconnaissance Orbiter reveal radar properties entirely consistent with massive water ice, supporting the debris-covered glacier hypothesis. The results imply that these glaciers formed in a previous climate conducive to glaciation at middle latitudes. Such features may collectively represent the most extensive nonpolar ice yet recognized on Mars.
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We thank F. Russo, M. Cutigni, O. Fuga, and E. Giacomoni of the SHARAD Operations Center for their role in acquiring the data over these targets; F. Bernardini for his assistance in the U.S. data processing effort; and two anonymous reviewers for their comments and suggestions. Work at the University of Texas was supported by the Institute for Geophysics of the Jackson School of Geosciences and NASA grant NAG5-12693 (J.W.H.). MRO is operated for NASA by Caltech's Jet Propulsion Laboratory. SHARAD was provided to MRO by the Italian Space Agency through a contract with Thales Alenia Space Italia and is operated by the INFOCOM Department, University of Rome. This is UTIG contribution 2006.
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Published In
Science
Volume 322 | Issue 5905
21 November 2008
21 November 2008
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American Association for the Advancement of Science.
Submission history
Received: 5 August 2008
Accepted: 3 October 2008
Published in print: 21 November 2008
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