TORSION IN THE SPACE OF COMMUTING ELEMENTS IN A LIE GROUP (New trends of transformation groups)

Let G be a compact connected Lie group, and let Hom (ℤ[m]，G) denote the space of homomorphisms from a free abelian group ℤ[m] to G. We study the problem of which primes p Hom (ℤ[m]，G) has p-torsion in homology. We give a new homotopy decomposition of the space, and we prove that Hom(ℤ[m], SU(n)) for m ≥ 2 hasp-torsion in homology if and only if p ≤ n. In this text we overview the proof and observe some examples

Taxonomic studies on the crabs of the Nagai Collection preserved in the Wakayama Prefectural Museum of Natural History IV. Six rare species of the family Parthenopidae

和歌山県立自然博物館所蔵のカニ類標本（永井コレクション）の分類学的研究．IV．ヒシガニ科の6 稀種和歌山県立自然博物館所蔵のカニ類標本（永井コレクション）の分類学的研究の第4報として|下記のヒシガニ科6種を記録した。ヒメカルイシガニDaldorfia leprosa （Nobili, 1905）；コオキナガニ（新称）Aulacolambrus hystricosus Tan & Ng, 2003；サンカクカワリヒシガニCryptopodia contracta Stimpson, 1857；ツバサカワリヒシガニ（新称）Furtipodia petrosa（Klunzinger,1906）；アバタハナヒシガニGarthambrus lacunosus（Rathbun, 1906）；ツノダシヒシガニモドキRhinolambrus lamelliger（White,1847）。これらはMarumura & Kosaka（2003）1）により永井コレクションの標本目録に学名と和名|標本の記録のみが記されているが|本報文で学名の変更と誤同定の修正を行い|ヒメカルイシガニ以外の5 種を正式に日本新記録種とした

Constraints on the mass of a habitable planet with water of nebular origin

From an astrobiological point of view, special attention has been paid to the probability of habitable planets in extrasolar systems. The purpose of this study is to constrain a possible range of the mass of a terrestrial planet that can get water. We focus on the process of water production through oxidation of the atmospheric hydrogen--the nebular gas having been attracted gravitationally--by oxide available at the planetary surface. For the water production to work well on a planet, a sufficient amount of hydrogen and enough high temperature to melt the planetary surface are needed. We have simulated the structure of the atmosphere that connects with the protoplanetary nebula for wide ranges of heat flux, opacity, and density of the nebular gas. We have found both requirements are fulfilled for an Earth-mass planet for wide ranges of the parameters. We have also found the surface temperature of planets of <= 0.3 Earth masses is lower than the melting temperature of silicate (~ 1500K). On the other hand, a planet of more than several Earth masses becomes a gas giant planet through runaway accretion of the nebular gas.Comment: 25 pages, 8 figures, to appear in the 01 September 2006 issue of Ap

Effects of Ram-Pressure from Intracluster Medium on the Star Formation Rate of Disk Galaxies in Clusters of Galaxies

Using a simple model of molecular cloud evolution, we have quantitatively estimated the change of star formation rate (SFR) of a disk galaxy falling radially into the potential well of a cluster of galaxies. The SFR is affected by the ram-pressure from the intracluster medium (ICM). As the galaxy approaches the cluster center, the SFR increases to twice the initial value, at most, in a cluster with high gas density and deep potential well, or with a central pressure of $\sim 10^{-2} cm^{-3} keV$ because the ram-pressure compresses the molecular gas of the galaxy. However, this increase does not affect the color of the galaxy significantly. Further into the central region of the cluster ($\lesssim 1$ Mpc from the center), the SFR of the disk component drops rapidly due to the effect of ram-pressure stripping. This makes the color of the galaxy redder and makes the disk dark. These effects may explain the observed color, morphology distribution and evolution of galaxies in high-redshift clusters. By contrast, in a cluster with low gas density and shallow potential well, or the central pressure of $\sim 10^{-3} cm^{-3} keV$, the SFR of a radially infalling galaxy changes less significantly, because neither ram-pressure compression nor stripping is effective. Therefore, the color of galaxies in poor clusters is as blue as that of field galaxies, if other environmental effects such as galaxy-galaxy interaction are not effective. The predictions of the model are compared with observations.Comment: 19 pages, 9 figures, to appear in Ap