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  • 1
    Publication Date: 2018-06-11
    Description: HERO's are objects which are very red in NIR colors. We report the discovery of a HERO in the field which includes a known radio galaxy, 53WOO2, and a possible cluster of glaxies both at z = 2.39.
    Keywords: Astrophysics
    Type: Astrophysical Journal Letters
    Format: text
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  • 2
    Publication Date: 2016-07-31
    Description: We investigate the properties of z  = 2.23 Hα and [O iii ] 5007 emitters using the narrow-band-selected samples obtained from the High- z Emission Line Survey. We construct two samples of the Hα and [O iii ] emitters and compare their integrated physical properties. We find that the distribution of stellar masses, dust extinction, star formation rates (SFRs), and specific SFRs (sSFRs) is not statistically different between the two samples. When we separate the full galaxy sample into three subsamples according to the detections of the Hα and/or [O iii ] emission lines, most of the sources detected with both Hα and [O iii ] show log(sSFR UV ) –9.5. The comparison of the three subsamples suggests that sources with strong [O iii ] line emission tend to have the highest star-forming activity out all galaxies that we study. We argue that the [O iii ] emission line can be used as a tracer of star-forming galaxies at high redshift, and that it is especially useful to investigate star-forming galaxies at z  〉 3, for which Hα emission is no longer observable from the ground.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
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  • 3
    Publication Date: 2015-12-01
    Description: We report the discovery of an extremely dense group of massive galaxies at the centre of the protocluster at z  = 3.09 in the SSA22 field from near-infrared spectroscopy conducted with the multi-object infrared camera and spectrograph (MOIRCS) on the Subaru Telecope. The newly discovered group comprises seven galaxies confirmed at z spec 3.09 within 180 kpc, including five massive objects with the stellar masses larger than 10 10.5 M and is associated with a bright submillimetre source SSA22-AzTEC14. The dynamical mass of the group estimated from the line-of-sight velocity dispersion of the members is M dyn  ~ 1.6 ± 0.3  x  10 13 M . Such a dense group is expected to be very rare at high redshift, as we have found only a few comparable systems in large-volume cosmological simulations. Such rare groups in simulations are hosted in collapsed haloes with M vir  = 10 13.4 –10 14.0 M and evolve into the brightest cluster galaxies (BCGs) of the most massive clusters at present. The observed AzTEC14 group at z  = 3.09 is therefore very likely to be a proto-BCG in the multiple merger phase. The observed total stellar mass of the group is $5.8^{+5.1}_{-2.0}\times 10^{11} \,\mathrm{M}_{{{\odot }}}$ , which suggests that over half the stellar mass of its descendant had been formed by z  = 3. Moreover, we have identified over two members for each of the four Lyα blobs (LABs) using our new spectroscopic data. This verifies our previous argument that many of the LABs in the SSA22 protocluster associated with multiple developed stellar components.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
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  • 4
    Publication Date: 2015-11-25
    Description: During the human in vitro fertilization procedure in the assisted reproductive technology, intracytoplasmic sperm injection is routinely used to inject a spermatozoon or a less mature elongating spermatid into the oocyte. In some infertile men, round spermatids (haploid male germ cells that have completed meiosis) are the most mature cells...
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 5
    Publication Date: 2015-08-23
    Description: Hydrolysis of carbohydrates is a major bioreaction in nature, catalyzed by glycoside hydrolases (GHs). We used neutron diffraction and high-resolution x-ray diffraction analyses to investigate the hydrogen bond network in inverting cellulase Pc Cel45A, which is an endoglucanase belonging to subfamily C of GH family 45, isolated from the basidiomycete Phanerochaete chrysosporium . Examination of the enzyme and enzyme-ligand structures indicates a key role of multiple tautomerizations of asparagine residues and peptide bonds, which are finally connected to the other catalytic residue via typical side-chain hydrogen bonds, in forming the "Newton’s cradle"–like proton relay pathway of the catalytic cycle. Amide–imidic acid tautomerization of asparagine has not been taken into account in recent molecular dynamics simulations of not only cellulases but also general enzyme catalysis, and it may be necessary to reconsider our interpretation of many enzymatic reactions.
    Electronic ISSN: 2375-2548
    Topics: Natural Sciences in General
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  • 6
    Publication Date: 2015-08-24
    Description: Using star-forming galaxies sample in the nearby Universe (0.02 〈  z  〈 0.10) selected from the Sloan Digital Sky Survey (DR7) and Galaxy Evolution Explorer all-sky survey (GR5), we present a new empirical calibration for predicting dust extinction of galaxies from the Hα-to-FUV flux ratio. We find that the Hα dust extinction ( A Hα ) derived with Hα/Hβ ratio (Balmer decrement) increases with increasing Hα/UV ratio as expected, but there remains a considerable scatter around the relation, which is largely dependent on stellar mass and/or Hα equivalent width (EW Hα ). At fixed Hα/UV ratio, galaxies with higher stellar mass (or galaxies with lower EW Hα ) tend to be more highly obscured by dust. We quantify this trend and establish an empirical calibration for predicting A Hα with a combination of Hα/UV ratio, stellar mass, and EW Hα , with which we can successfully reduce the systematic uncertainties accompanying the simple Hα/UV approach by ~15–30 per cent. The new recipes proposed in this study will provide a convenient tool for predicting dust extinction level of galaxies particularly when Balmer decrement is not available. By comparing A Hα (derived with Balmer decrement) and A UV (derived with IR/UV luminosity ratio) for a subsample of galaxies for which AKARI far-infrared photometry is available, we demonstrate that more massive galaxies tend to have higher extra extinction towards the nebular regions compared to the stellar continuum light. Considering recent studies reporting smaller extra extinction towards nebular regions for high-redshift galaxies, we argue that the dust geometry within high-redshift galaxies resembles low-mass galaxies in the nearby Universe.
    Print ISSN: 0035-8711
    Electronic ISSN: 1365-2966
    Topics: Physics
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  • 7
    Publication Date: 2013-11-09
    Description: Tidal mixing and its associated iron and nutrients flux from a subsurface layer along the shelf break has been considered as one of the key processes to maintain the high summertime biological productivity in the Green Belt in the southeastern Bering Sea. In the present study, tidal mixing near the shelf break is examined with a three-dimensional high-resolution numerical model to quantify the enhanced mixing and to reveal the underlying physical mechanisms based on the different characteristics of diurnal and semi-diurnal internal waves. Strong turbulent mixing with energy dissipation rates of over 1 × 10 -8 W/kg is reproduced along the Green Belt in the numerical model forced by barotropic diurnal and/or semi-diurnal tides at open boundaries. The energy dissipation off the shelf break near the sea surface is enhanced due to the semi-diurnal internal waves, whereas the dissipation near the bottom of the shelf break is enhanced by the diurnal topographically trapped waves. An additional experiment with stratification representative of winter conditions shows a significant influence of stratification on the energy dissipation off the shelf break due to the change in features of both diurnal and semi-diurnal internal waves. Low-mode semi-diurnal baroclinic energy flux from the Aleutian Passes is shown to increase the energy dissipation along the shelf slope between Pribilof and Zhemchug Canyons. These results suggest that the strong vertical mixing along the shelf break induced by the diurnal and semi-diurnal tides both play important roles in maintaining the iron and nutrients supply along the Green Belt.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
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  • 8
    Publication Date: 2013-12-25
    Description: Nucleotide polymerization proceeds in the forward (5′-3′) direction. This tenet of the central dogma of molecular biology is found in diverse processes including transcription, reverse transcription, DNA replication, and even in lagging strand synthesis where reverse polymerization (3′-5′) would present a “simpler” solution. Interestingly, reverse (3′-5′) nucleotide addition is catalyzed...
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 9
    Publication Date: 2013-03-30
    Description: Transition-metal L 2,3 XANES spectra are widely used to determine coordination and valence of the target ion. For decades, experimental fingerprinting, i.e., the comparison with spectra obtained from known reference compounds was the way to interpret spectral features. This approach was based on the common understanding that only anions in the first coordination sphere would determine the near-edge structure, and crystalline references were selected accordingly. Using ab initio charge-transfer multiplet calculations, we demonstrate that there is also a significant impact on spectral features from the second-nearest neighbor cations. This finding is exemplified for three fresnoite-type vanadates, namely Ba 2 VSi 2 O 8 (BVS), K 2 VV 2 O 8 (KVV), and Rb 2 VV 2 O 8 (RVV). The theoretical treatment provides evidence that for the three compounds studied it is not variable bond lengths or bond angles between vanadium and oxygen that make the V- L 2 , 3 XANES spectra different, but the interaction of the target vanadium ions with its neighboring cations (Si for BVS, V for KVV and RVV), which dominates. Therefore, we conclude that simple fingerprinting can result in misleading interpretations when interactions with second-nearest neighboring cations are not taken into account. Ab initio charge-transfer multiplet calculations of spectral shapes (theoretical fingerprinting) should be employed instead to get a deeper understanding of structure-spectra relationships, or the choice of reference spectra should take into account second-nearest neighbors. Our findings are similarly important for the interpretation of electron energy-loss near-edge (ELNES) spectra.
    Print ISSN: 0003-004X
    Electronic ISSN: 1945-3027
    Topics: Geosciences
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  • 10
    Publication Date: 2013-04-02
    Description: In animal ribosomes, two stalk proteins P1 and P2 form a heterodimer, and the two dimers, with the anchor protein P0, constitute a pentameric complex crucial for recruitment of translational GTPase factors to the ribosome. To investigate the functional contribution of each copy of the stalk proteins, we constructed P0 mutants, in which one of the two C-terminal helices, namely helix I (N-terminal side) or helix II (C-terminal side) were unable to bind the P1–P2 dimer. We also constructed ‘one-C-terminal domain (CTD) stalk dimers’, P1–P2 C and P1 C –P2, composed of intact P1/P2 monomer and a CTD-truncated partner. Through combinations of P0 and P1–P2 variants, various complexes were reconstituted and their function tested in eEF-2-dependent GTPase and eEF-1α/eEF-2-dependent polyphenylalanine synthesis assays in vitro . Double/single-CTD dimers bound to helix I showed higher activity than that bound to helix II. Despite low polypeptide synthetic activity by a single one-CTD dimer, its binding to both helices considerably increased activity, suggesting that two stalk dimers cooperate, particularly in polypeptide synthesis. This promotion of activity by two stalk dimers was lost upon mutation of the conserved YPT sequence connecting the two helices of P0, suggesting a role for this sequence in cooperativity of two stalk dimers.
    Print ISSN: 0305-1048
    Electronic ISSN: 1362-4962
    Topics: Biology
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