A model for the infrared dust emission from forming galaxies

In the early epoch of galaxy evolution, dust is only supplied by supernovae (SNe). With the aid of a new physical model of dust production by SNe developed by Nozawa et al. (2003) (N03), we constructed a model of dust emission from forming galaxies on the basis of the theoretical framework of Takeuchi et al. (2003) (T03). N03 showed that the produced dust species depends strongly on the mixing within SNe. We treated both unmixed and mixed cases and calculated the infrared (IR) spectral energy distribution (SED) of forming galaxies for both cases. Our model SED is less luminous than the SED of T03 model by a factor of 2-3. The difference is due to our improved treatment of UV photon absorption cross section, as well as different grain size and species newly adopted in this work. The SED for the unmixed case is found to have an enhanced near to mid-IR (N-MIR) continuum radiation in its early phase of the evolution (age < 10^{7.25} yr) compared with that for the mixed case. The strong N--MIR continuum is due to the emission from Si grains, which only exist in the species of the unmixed dust production. We also calculated the IR extinction curves for forming galaxies. Then we calculated the SED of a local starbursting dwarf galaxy SBS 0335-052. Our present model SED naturally reproduced the strong N--MIR continuum and the lack of cold FIR emission of SBS 0335-052. We found that only the SED of unmixed case can reproduce the NIR continuum of this galaxy. We then made a prediction for the SED of another typical star-forming dwarf, I Zw 18. We also presented the evolution of the SED of LBGs. Finally, we discussed the possibility of observing forming galaxies at z > 5.Comment: MNRAS, in press. 18 pages, 15 figures. Abstract abridge

Infrared Spectral Energy Distribution Model for Extremely Young Galaxies

The small grain sizes produced by Type II supernova (SN II) models in young, metal-poor galaxies make the appearance of their infrared (IR) spectral energy distribution (SED) quite different from that of nearby, older galaxies. To study this effect, we have developed a model for the evolution of dust content and the IR SED of low-metallicity, extremely young galaxies based on Hirashita et al. (2002). We find that, even in the intense ultraviolet (UV) radiation field of very young galaxies, small silicate grains are subject to stochastic heating resulting in a broad temperature distribution and substantial MIR continuum emission. Larger carbonaceous grains are in thermal equilibrium at T \simeq 50 - 100K, and they also contribute to the MIR. We present the evolution of SEDs and IR extinction of very young, low-metallicity galaxies. The IR extinction curve is also shown. In the first few Myrs, the emission peaks at \lambda \sim 30-50um at later times dust self-absorption decreases the apparent grain temperatures, shifting the bulk of the emission into the submillimetre band. We successfully apply the model to the IR SED of a low metallicity (1/41 Z_\odot) dwarf galaxy SBS0335-052. We find the SED, optical properties and extinction of the star forming region to be consistent with a very young and compact starburst. We also predict the SED of another extremely low-metallicity galaxy, I Zw 18, for future observational tests. Some prospects for future observations are discussed.Comment: MNRAS in press, pages, 6 figures, using mn2e.cls. Abstract abridge

The ISO 170um Luminosity Function of Galaxies

We constructed a local luminosity function (LF) of galaxies using a flux-limited sample (S_170 > 0.195Jy) of 55 galaxies at z < 0.3 taken from the ISO FIRBACK survey at 170um. The overall shape of the 170-um LF is found to be different from that of the total 60-um LF (Takeuchi et al. 2003): the bright end of the LF declines more steeply than that of the 60-um LF. This behavior is quantitatively similar to the LF of the cool subsample of the IRAS PSCz galaxies. We also estimated the strength of the evolution of the LF by assuming the pure luminosity evolution (PLE): L(z) \propto (1+z)^Q. We obtained Q=5.0^{+2.5}_{-0.5} which is similar to the value obtained by recent Spitzer observations, in spite of the limited sample size. Then, integrating over the 170-um LF, we obtained the local luminosity density at 170um, \rho_L(170um). A direct integration of the LF gives \rho_L(170um) = 1.1 \times 10^8 h Lsun Mpc^{-3}, whilst if we assume a strong PLE with Q=5, the value is 5.2 \times 10^7 h Lsun Mpc^{-3}. This is a considerable contribution to the local FIR luminosity density. By summing up with other available infrared data, we obtained the total dust luminosity density in the Local Universe, \rho_L(dust)=1.1 \times 10^8 h Lsun Mpc^{-3}. Using this value, we estimated the cosmic star formation rate (SFR) density hidden by dust in the Local Universe. We obtained \rho_SFR(dust) \simeq 1.1-1.2 h \times 10^{-2} Msun yr^{-1} Mpc^{-3}$, which means that 58.5% of the star formation is obscured by dust in the Local Universe.Comment: A&A in pres

Exploring Galaxy Evolution from Infrared Number Counts and Cosmic Infrared Background

Recently reported infrared (IR) galaxy number counts and cosmic infrared background (CIRB) all suggest that galaxies have experienced a strong evolution sometime in their lifetime. We statistically estimate the galaxy evolution history from these data. We find that an order of magnitude increase of the far-infrared (FIR) luminosity at redshift z = 0.5 - 1.0 is necessary to reproduce the very high CIRB intensity at 140 um reported by Hauser et al. (1998). z \sim 0.75 and decreases to, even at most, a factor of 10 toward z \sim 5, though many variants are allowed within these constraints. This evolution history also satisfies the constraints from the galaxy number counts obtained by IRAS, ISO and, roughly, SCUBA. The rapid evolution of the comoving IR luminosity density required from the CIRB well reproduces the very steep slope of galaxy number counts obtained by ISO. We also estimate the cosmic star formation history (SFH) from the obtained FIR luminosity density, considering the effect of the metal enrichment in galaxies. The derived SFH increases steeply with redshift in 0 0.75. This is consistent with the SFH estimated from the reported ultraviolet luminosity density. In addition, we present the performance of the Japanese ASTRO-F FIR galaxy survey. We show the expected number counts in the survey. We also evaluate how large a sky area is necessary to derive a secure information of galaxy evolution up to z \sim 1 from the survey, and find that at least 50 - 300 deg^2 is required.Comment: 18 pages LaTeX, PASJ in press. Abstract abridge

Dendritic spinules in rat nigral neurons revealed by acetylcholinesterase immunocytochemistry and serial sections of the dendritic spine heads.

Dendritic spinules of rat nigral neurons were visualized at electron microscopic level by acetylcholinesterase immunocytochemistry and serial sections of the nigral dendrites. The spinules (at least 150 nm in length and 10-20 nm in width) which protruded from the spine heads are found in extracellular space in the neuropil and particularly between nerve terminals of the presynaptic neurons and fine glial processes. The nigral spinules are, however, not observed as invaginated processes in the nerve terminals. The dendritic spinule may be endowed with synaptic plasticity and metabolic exchange between nerve terminals and glial processes

New group of stable icosahedral quasicrystals: structural properties and formation conditions

Structural studies on the icosahedral quasicrystals in Zn-Mg-Sc, Cu-Ga-Mg-Sc, and Zn-Mg-Ti alloys as well as their corresponding 1/1 cubic approximants, have revealed that these quasicrystals belong to a new structural group similar to Cd-based quasicrystals. This group is characterized by a triple-shell icosahedral cluster different from both Mackay- and Bergman-types. The presence of the atomic cluster has been deduced from the structure model of the approximant crystal, Zn17Sc3, in which the clusters are embedded in a periodic network of so-called "glue atoms". Density measurement suggested the presence of at least 2.7 Zn atoms in the first shell of the cluster in this approximant. The substitutional relationship in these three quasicrystals indicates the important role of Hume-Rothery rule for the formation of this type of quasicrystal. The occurrence of a P-type icosahedral quasicrystal in Zn-Mg-Yb alloy is also reported.Comment: 11 pages, 1 table, 6 figure

Immunohistochemical expression of keratan sulfate: a possible diagnostic marker for carcinomas of the female genital tract

Aims The authors previously reported the expression of keratan sulfate (KS), a glycosaminoglycan, in the epithelium of normal and neoplastic endometria. The aim of this study was to evaluate its potential use as a diagnostic marker, and the expression of KS was investigated in other human epithelial tissues. Methods Expression was examined immunohistochemically using 102 samples of normal epithelia and 110 samples of carcinomas from the female genital tract (FGT; cervix, endometrium, ovary, fallopian tube), digestive organs (gastrointestinal tract, pancreas, liver), urinary tract, lung, mammary gland, thyroid and mesothelium. Results In normal tissues, KS was consistently detected in the FGT and ectopic endometrium (25/26), but was not found in the digestive organs (1/42) and urinary tract (0/6), and was only partly detected in the lung (7/10), mammary gland (3/9) and thyroid (4/4). In malignant tissues, KS was consistently observed in carcinomas of the endometrium, ovary and fallopian tube (29/32), and was partly detected in carcinomas of the lung, mammary gland, thyroid, pancreas and mesothelium, but was absent in carcinomas of the gastrointestinal tract (0/17), liver (0/5) and urinary tract (0/11). Among carcinomas of the FGT, digestive organs and urinary tract, KS positivity suggested the possibility of FGT carcinomas, with 79.5% (31/39) sensitivity and 92.9% (39/42) specificity. Conclusions KS is a potentially useful marker for the supportive diagnosis of the primary site of metastatic carcinomas or unknown primary carcinomas, especially in the abdominal cavity.ArticleJOURNAL OF CLINICAL PATHOLOGY. 64(12):1058-1063 (2011)journal articl

STERNOCLAVICULAR JOINT MOVEMENT DURING BACKSWING IN BASEBALL PITCHING MAY BE A GOOD INDICATOR OF SHOULDER INJURY

The purpose of this study was to demonstrate the characteristics of joint movements performed by the pitchers who suffered from throwing shoulder injuries. Fourteen semiprofessional baseball pitchers participated in our longitudinal study. We captured their pitching using an optical motion capture system. We investigated their disease history once a year, for 5 years, in order to investigate the relationship between baseball-related throwing injuries and pitching mechanics. T w of the players suffered from shoulder pain and had to take a "no throw" rest for several weeks during the season. Both pitchers had a reduced range of motions for retraction at the sternoclavicular joint during backswing. However, they presented the same range of motions for shoulder horizontal abduction, as the other healthy pitchers