《Nature》目录要览：2010-12-16出版
时间：2010-12-16 阅读： 我要评论:
http://www.nature.com/nature/journal/v468/n7326/full/nature09564.html
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LETTERS
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A substantial population of low-mass stars in luminous elliptical galaxies pp940 - 942
The stellar initial mass function describes the mass distribution of stars at the time of their formation. This study reports observations of the Na I doublet and the Wing-Ford molecular FeH band in the spectra of elliptical galaxies. These lines are strong in stars with masses
Pieter G. van Dokkum and Charlie Conroy
doi:10.1038/nature09578
Abstract: http://www.nature.com/nature/journal/v468/n7326/abs/nature09578.html
Article: http://www.nature.com/nature/journal/v468/n7326/full/nature09578.html
Origin of Saturn’s rings and inner moons by mass removal from a lost Titan-sized satellite p943
Saturn's rings are more than 90–95% water ice, which implies that initially they were almost pure ice because they are continually polluted by rocky meteoroids. Saturn has only one large satellite, Titan, whereas Jupiter has four large satellites; additional large satellites probably existed originally but were lost as they spiralled into Saturn. Now, numerical simulations of the tidal removal of mass from a differentiated, Titan sized satellite as it migrates inward towards Saturn are reported. Planetary tidal forces preferentially strip material from the satellite's outer icy layers, while its rocky core remains intact and is lost to collision with the planet. The result is a pure ice ring.
Robin M. Canup
doi:10.1038/nature09661
Abstract: http://www.nature.com/nature/journal/v468/n7326/abs/nature09661.html
Article: http://www.nature.com/nature/journal/v468/n7326/full/nature09661.html
Pleats in crystals on curved surfaces pp947 - 951
Hexagons can easily tile a flat surface, but not a curved one. Defects with topological charge (such as heptagons and pentagons) make it easier to tile curved surfaces, such as soccer balls. Here, a new type of defect is reported that accommodates curvature in the same way as fabric pleats. The appearance of such defects on the negatively curved surfaces of stretched colloidal crystals are observed. The results will facilitate the exploration of general theories of defects in curved spaces, the engineering of curved structures and novel methods for soft lithography and directed self-assembly.
William T. M. Irvine, Vincenzo Vitelli and Paul M. Chaikin
doi:10.1038/nature09620
Abstract: http://www.nature.com/nature/journal/v468/n7326/abs/nature09620.html
Article: http://www.nature.com/nature/journal/v468/n7326/full/nature09620.html
Tidal dissipation and the strength of the Earth’s internal magnetic field pp952 - 954
Here, an indirect estimate for the magnetic field strength within the Earth's core from measurements of tidal dissipation is presented. Previously reported evidence of anomalous dissipation in the Earth's nutations can be explained with a core-averaged field of 2.5 mT, eliminating the need for high fluid viscosity or a stronger magnetic field at the inner-core boundary.
Bruce A. Buffett
doi:10.1038/nature09643
Abstract: http://www.nature.com/nature/journal/v468/n7326/abs/nature09643.html
Article: http://www.nature.com/nature/journal/v468/n7326/full/nature09643.html
----------------------
LETTERS
----------------------
A substantial population of low-mass stars in luminous elliptical galaxies pp940 - 942
The stellar initial mass function describes the mass distribution of stars at the time of their formation. This study reports observations of the Na I doublet and the Wing-Ford molecular FeH band in the spectra of elliptical galaxies. These lines are strong in stars with masses
Pieter G. van Dokkum and Charlie Conroy
doi:10.1038/nature09578
Abstract: http://www.nature.com/nature/journal/v468/n7326/abs/nature09578.html
Article: http://www.nature.com/nature/journal/v468/n7326/full/nature09578.html
Origin of Saturn’s rings and inner moons by mass removal from a lost Titan-sized satellite p943
Saturn's rings are more than 90–95% water ice, which implies that initially they were almost pure ice because they are continually polluted by rocky meteoroids. Saturn has only one large satellite, Titan, whereas Jupiter has four large satellites; additional large satellites probably existed originally but were lost as they spiralled into Saturn. Now, numerical simulations of the tidal removal of mass from a differentiated, Titan sized satellite as it migrates inward towards Saturn are reported. Planetary tidal forces preferentially strip material from the satellite's outer icy layers, while its rocky core remains intact and is lost to collision with the planet. The result is a pure ice ring.
Robin M. Canup
doi:10.1038/nature09661
Abstract: http://www.nature.com/nature/journal/v468/n7326/abs/nature09661.html
Article: http://www.nature.com/nature/journal/v468/n7326/full/nature09661.html
Pleats in crystals on curved surfaces pp947 - 951
Hexagons can easily tile a flat surface, but not a curved one. Defects with topological charge (such as heptagons and pentagons) make it easier to tile curved surfaces, such as soccer balls. Here, a new type of defect is reported that accommodates curvature in the same way as fabric pleats. The appearance of such defects on the negatively curved surfaces of stretched colloidal crystals are observed. The results will facilitate the exploration of general theories of defects in curved spaces, the engineering of curved structures and novel methods for soft lithography and directed self-assembly.
William T. M. Irvine, Vincenzo Vitelli and Paul M. Chaikin
doi:10.1038/nature09620
Abstract: http://www.nature.com/nature/journal/v468/n7326/abs/nature09620.html
Article: http://www.nature.com/nature/journal/v468/n7326/full/nature09620.html
Tidal dissipation and the strength of the Earth’s internal magnetic field pp952 - 954
Here, an indirect estimate for the magnetic field strength within the Earth's core from measurements of tidal dissipation is presented. Previously reported evidence of anomalous dissipation in the Earth's nutations can be explained with a core-averaged field of 2.5 mT, eliminating the need for high fluid viscosity or a stronger magnetic field at the inner-core boundary.
Bruce A. Buffett
doi:10.1038/nature09643
Abstract: http://www.nature.com/nature/journal/v468/n7326/abs/nature09643.html
Article: http://www.nature.com/nature/journal/v468/n7326/full/nature09643.html
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来源：Nature 作者：Environmentor （环境人 Environmentor.Cn）
