192 research outputs found
国際的・国内的双方のコンテキストにおける教育政策の平等・公正・包摂の概念規定と社会集団 : カンボジアにおけるニーズと現実の相克
早大学位記番号:新7011早稲田大
Luminosity dependent clustering of star-forming BzK galaxies at redshift 2
We use the BzK color selection proposed by Daddi et al. (2004) to obtain a
sample of 1092 faint star-forming galaxies (hereafter sBzKs) from 180 arcmin^2
in the Subaru Deep Field. This sample represents star-forming galaxies at 1.4 <
z < 2.5 down to K(AB)=23.2, which roughly corresponds to a stellar-mass limit
of ~ 1 x 10^{10} Msun. We measure the angular correlation function (ACF) of
these sBzKs to be w(theta) = (0.58 +- 0.13) x theta["]^{-0.8} and translate the
amplitude into the correlation length assuming a reasonable redshift
distribution. The resulting value, r0 = 3.2^{+0.6}_{-0.7} h^{-1} Mpc, suggests
that our sBzKs reside in haloes with a typical mass of 2.8 x 10^{11} Msun.
Combining this halo mass estimate with those for brighter samples of Kong et
al. (2006), we find that the mass of dark haloes largely increases with K
brightness, a measure of the stellar mass. Comparison with other galaxy
populations suggests that faint sBzKs (K(AB)<23.2) and Lyman Break Galaxies at
z ~ 2 are similar populations hosted by relatively low-mass haloes, while
bright sBzKs (K(AB)<21) reside in haloes comparable to or more massive than
those of Distant Red Galaxies and Extremely Red Objects. Using the extended
Press-Schechter formalism, we predict that present-day descendants of haloes
hosting sBzKs span a wide mass range depending on K brightness, from lower than
that of the Milky Way up to those of richest clusters.Comment: 14 pages, 9 figures, accepted for publication in Ap
Star Formation Rates and Metallicities of K-selected Star Forming Galaxies at z~2
We present spectroscopy of 15 star-forming BzK galaxies (sBzKs) with K(AB)<23
in the Subaru Deep Field, for which Halpha and some other emission lines are
detected in 0.9 to 2.3 micron spectra with a resolution of R=500. Using Halpha
luminosities, we obtain star formation rates (SFRs), and then specific SFRs
(SSFRs) dividing SFRs by stellar masses, which are derived from SED fitting to
BVRi'z'K photometry. It is found that sBzKs with higher stellar masses have
larger SFRs. A negative correlation is seen between stellar mass and SSFR,
which is consistent with the previous results for z~2 galaxies. This implies
that a larger growth of stellar mass occurs in less massive galaxies. In
addition, gas-phase oxygen abundances, 12+log(O/H), are derived from the ratio
of NII(lambda 6584) to Halpha using the N2 index method. We have found a
correlation between stellar mass and oxygen abundance in the sense that more
massive sBzKs tend to be more metal rich, which is qualitatively consistent
with the relation for UV-selected z~2 galaxies. However, the metallicity of the
sBzKs is ~0.2 dex higher than that of UV-selected galaxies with similar stellar
masses, which is significant considering the small uncertainties. The sBzKs in
our sample have redder R-K colors than the UV-selected galaxies. This galaxy
color-dependence in the oxygen abundance may be caused by older or dustier
galaxies having higher metallicities at z~2.Comment: 20 pages, 13 figures, 2 tables, accepted for publication in The
Astrophysical Journa
A Proposal for New Algorithm that Defines Gait-Induced Acceleration and Gait Cycle in Daily Parkinsonian Gait Disorders
We developed a new device, the portable gait rhythmogram (PGR), to record up to 70 hrs of movement-induced accelerations. Acceleration values induced by various movements, averaged every 10 min, showed gamma distribution, and the mean value of this distribution was used as an index of the amount of overall movements. Furthermore, the PGR algorithm can specify gait-induced accelerations using the pattern-matching method. Analysis of the relationship between gait-induced accelerations and gait cycle duration makes it possible to quantify Parkinson’s disease (PD)-specific pathophysiological mechanisms underlying gait disorders. Patients with PD showed the following disease-specific patterns: (1) reduced amount of overall movements and (2) low amplitude of gait-induced accelerations in the early stages of the disease, which was compensated by fast stepping. Loss of compensation was associated with slow stepping gait, (3) narrow range of gait-induced acceleration amplitude and gait cycle duration, suggesting monotony, and (4) evident motor fluctuations during the day by tracing changes in the above two parameters. Prominent motor fluctuation was associated with frequent switching between slow stepping mode and active mode. These findings suggest that monitoring various movement- and gait-induced accelerations allows the detection of specific changes in PD. We conclude that continuous long-term monitoring of these parameters can provide accurate quantitative assessment of parkinsonian clinical motor signs
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