Simulations of normal spiral galaxies     

Roelof Bottema 《Monthly notices of the Royal Astronomical Society》2003,344(2):358-384

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On determining the cluster abundance normalization     

Elena Pierpaoli  Stefano Borgani  Douglas Scott  Martin White 《Monthly notices of the Royal Astronomical Society》2003,342(1):163-175

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Application of the global modal approach to the spiral galaxies     

Natalia Orlova  Vladimir Korchagin  Nobuhiro Kikuchi  Shoken. M. Miyama  Aleksei Moiseev 《Astrophysics and Space Science》2003,284(2):739-742

We have tested the applicability of the global modal approach in the density wave theory of spiral structure for a sample of spiral galaxies with measured axisymmetric background properties. We report here the results of the simulations for four galaxies: NGC 488, NGC 628, NGC 1566, and NGC 3938. Using the observed radial distributions for the stellar velocity dispersions and the rotation velocities we have constructed the equilibrium models for the galactic disks in each galaxy and implemented two kinds of stability analyses - the linear global analysis and 2D-nonlinear simulations. In general, the global modal approach is able to reproduce the observed properties of the spiral arms in the galactic disks. The growth of spirals in the galactic disks can be physically understood in terms of amplification by over-reflection at the corotation resonance. Our results support the global modal approach as a theoretical explanation of spiral structure in galaxies. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Microsatellite Variation in the Oyster Crassostreaplicatula Along the Coast of China     

YU Hong  LI Qi YU Ruihai 《中国海洋大学学报(英文版)》2008,7(4)

Genetic diversity and differentiation of the oyster Crassostreaplicatula populations from China's coast were studied basedon seven microsatellite loci.All loci showed high polymorphism for all five C.plicatula populations,with an average number of alleleper locus of 19.3-27.9 and an average expected heterozygosity of 0.889-0.952.Significant departures from Hardy-Weinberg equilib-rium and deficits of heterozygotes were observed over most populations at each locus,which were fully explained by null alleles.Microsatellite analysis revealed significant subdivision in the C.plicatula populations.According to the neighbor-joining tree con-structed on the basis of the D,A distance,the five populations fell into three regional groups,showing a relatively homogeneous geneticstructure in geographically close populations.Assignation tests correctly assigned high percentages of individuals to their originalpopulations and groups,and also confirmed the existence of genetic differentiation among C.plicatula populations.The results ob-tained in this study will facilitate the formulation of appropriate fisheries management programs,stock identification and conservationof biodiversity for the species.  相似文献   

FLASH redshift survey – I. Observations and catalogue     

Raven Kaldare  Matthew Colless  Somak Raychaudhury  B. A. Peterson 《Monthly notices of the Royal Astronomical Society》2003,339(3):652-662

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The environmental dependence of clustering in hierarchical models     

Ummi Abbas  Ravi K. Sheth 《Monthly notices of the Royal Astronomical Society》2005,364(4):1327-1336

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Numerical simulations of weak lensing measurements     

David J. Bacon  Alexandre Refregier  Douglas Clowe  Richard S. Ellis 《Monthly notices of the Royal Astronomical Society》2001,325(3):1065-1074

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Recovering the initial conditions of our local Universe from NOG and PSCz catalogues     

Fabio Fontanot  Pierluigi Monaco  Stefano Borgani 《Monthly notices of the Royal Astronomical Society》2003,341(2):692-706

We apply the ztrace algorithm to the optical NOG and infrared PSC z galaxy catalogues to reconstruct the pattern of primordial fluctuations that have generated our local Universe. We check that the density fields traced by the two catalogues are well correlated, and consistent with a linear relation [either in δ or in  log (1 +δ)  ] with relative bias (of NOG with respect to PSC z )   b _rel= 1.1 ± 0.1  . The relative bias relation is used to fill the optical zone of avoidance at  | b | < 20°  using the PSC z galaxy density field.
We perform extensive testing on simulated galaxy catalogues to optimize the reconstruction. The quality of the reconstruction is predicted to be good at large scales, up to a limiting wavenumber   k _lim≃ 0.4 h Mpc⁻¹  beyond which all information is lost. We find that the improvement arising from the denser sampling of the optical catalogue is compensated by the uncertainties connected to the larger zone of avoidance.
The initial conditions reconstructed from the NOG catalogue are found (analogously to those from the PSC z ) to be consistent with a Gaussian paradigm. We use the reconstructions to produce sets of initial conditions ready to be used for constrained simulations of our local Universe.  相似文献   

Two 100-Mpc-scale structures in the three-dimensional distribution of radio galaxies and their implications     

Kate Brand  Steve Rawlings  Gary J. Hill  Mark Lacy  Ewan Mitchell  Joe Tufts 《Monthly notices of the Royal Astronomical Society》2003,344(1):283-306

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桂东南宁潭岩体地质特征及其构造环境初探     

陆济璞  蔡贺清 《南方国土资源》2002,15(4):11-16

宁潭岩体是由马田、亭子、陈冲、老虎头 4个单元组成的遭受了变形变质改造的花岗岩复式岩体。岩石学、岩石化学、地球化学特征反映该岩体属后碰撞强过铝花岗岩。其源区既包含有不成熟的富含长英质物质的特性 ,也有成熟的、富含粘土的特性。岩体的形成温度为 85 0～ 92 5℃ ,同位素年龄为 35 4～ 4 4 0Ma。可能是加里东期扬子板块与华夏板块碰撞后 ,在拉伸构造作用下岩浆底辟侵位而成  相似文献