648 research outputs found
"Direct" Gas-phase Metallicities, Stellar Properties, and Local Environments of Emission-line Galaxies at Redshift below 0.90
Using deep narrow-band (NB) imaging and optical spectroscopy from the Keck
telescope and MMT, we identify a sample of 20 emission-line galaxies (ELGs) at
z=0.065-0.90 where the weak auroral emission line, [OIII]4363, is detected at
>3\sigma. These detections allow us to determine the gas-phase metallicity
using the "direct'' method. With electron temperature measurements and dust
attenuation corrections from Balmer decrements, we find that 4 of these
low-mass galaxies are extremely metal-poor with 12+log(O/H) <= 7.65 or
one-tenth solar. Our most metal-deficient galaxy has 12+log(O/H) =
7.24^{+0.45}_{-0.30} (95% confidence), similar to some of the lowest
metallicity galaxies identified in the local universe. We find that our
galaxies are all undergoing significant star formation with average specific
star formation rate (SFR) of (100 Myr)^{-1}, and that they have high central
SFR surface densities (average of 0.5 Msun/yr/kpc^2. In addition, more than
two-thirds of our galaxies have between one and four nearby companions within a
projected radius of 100 kpc, which we find is an excess among star-forming
galaxies at z=0.4-0.85. We also find that the gas-phase metallicities for a
given stellar mass and SFR lie systematically below the local M-Z-(SFR)
relation by \approx0.2 dex (2\sigma\ significance). These results are partly
due to selection effects, since galaxies with strong star formation and low
metallicity are more likely to yield [OIII]4363 detections. Finally, the
observed higher ionization parameter and electron density suggest that they are
lower redshift analogs to typical z>1 galaxies.Comment: Accepted for publication in the Astrophysical Journal (15 November
2013). 31 pages in emulateapj format with 16 figures and 7 tables. Revised to
address referee's comments, which include discussion on selection effects,
similarities to green pea galaxies, and nebular continuum contribution.
Modifications were made for some electron temperature and metallicity
measurement
Recent development of sulfide solid electrolytes and interfacial modification for all-solid-state rechargeable lithium batteries
AbstractRecent development of inorganic sulfide solid electrolytes and all-solid-state rechargeable lithium batteries with them is reviewed. Electrical conductivity, electrochemical stability and chemical stability of these sulfide electrolytes are reported. Formation of favorable solid–solid contacts between electrode and electrolyte is important in all-solid-state batteries. Useful techniques to achieving intimate electrode–electrolyte interfaces are proposed. Application of sulfur positive electrode and lithium metal negative electrode with large theoretical capacity to all-solid-state lithium batteries is demonstrated
Unique features of the rice blast resistance Pish locus revealed by large scale retrotransposon-tagging
<p>Abstract</p> <p>Background</p> <p><it>R </it>gene-mediated resistance is one of the most effective mechanisms of immunity against pathogens in plants. To date some components that regulate the primary steps of plant immunity have been isolated, however, the molecular dissection of defense signaling downstream of the R proteins remains to be completed. In addition, <it>R </it>genes are known to be highly variable, however, the molecular mechanisms responsible for this variability remain obscure.</p> <p>Results</p> <p>To identify novel factors required for <it>R </it>gene-mediated resistance in rice, we used rice insertional mutant lines, induced by the endogenous retrotransposon <it>Tos17</it>, in a genetic screening involving the rice blast fungus <it>Magnaporthe oryzae</it>. We inoculated 41,119 mutant lines with the fungus using a high throughput procedure, and identified 86 mutant lines with diminished resistance. A genome analysis revealed that 72 of the 86 lines contained mutations in a gene encoding a nucleotide binding site (NBS) and leucine rich repeat (LRR) domain-containing (NBS-LRR) protein. A genetic complementation analysis and a pathogenesis assay demonstrated that this NBS-LRR gene encodes Pish, which confers resistance against races of <it>M. oryzae </it>containing <it>avrPish</it>. The other 14 lines have intact copies of the <it>Pish </it>gene, suggesting that they may contain mutations in the signaling components downstream of Pish. The genome analysis indicated that <it>Pish </it>and its neighboring three NBS-LRR genes are high similar to one another and are tandemly located. An <it>in silico </it>analysis of a <it>Tos17 </it>flanking sequence database revealed that this region is a "hot spot" for insertion. Intriguingly, the insertion sites are not distributed evenly among these four NBS-LRR genes, despite their similarity at the sequence and expression levels.</p> <p>Conclusions</p> <p>In this work we isolated the <it>R </it>gene <it>Pish</it>, and identified several other mutants involved in the signal transduction required for <it>Pish</it>-mediated resistance. These results indicate that our genetic approach is efficient and useful for unveiling novel aspects of defense signaling in rice. Furthermore, our data provide experimental evidence that <it>R </it>gene clusters have the potential to be highly preferred targets for transposable element insertions in plant genomes. Based on this finding, a possible mechanism underlying the high variability of <it>R </it>genes is discussed.</p
Physical conditions of the interstellar medium in star-forming galaxies at z~1.5
We present results from Subaru/FMOS near-infrared (NIR) spectroscopy of 118
star-forming galaxies at in the Subaru Deep Field. These galaxies
are selected as [OII]3727 emitters at 1.47 and 1.62 from
narrow-band imaging. We detect H emission line in 115 galaxies,
[OIII]5007 emission line in 45 galaxies, and H,
[NII]6584, and [SII]6716,6731 in 13, 16, and 6
galaxies, respectively. Including the [OII] emission line, we use the six
strong nebular emission lines in the individual and composite rest-frame
optical spectra to investigate physical conditions of the interstellar medium
in star-forming galaxies at 1.5. We find a tight correlation between
H and [OII], which suggests that [OII] can be a good star formation
rate (SFR) indicator for galaxies at . The line ratios of
H/[OII] are consistent with those of local galaxies. We also find that
[OII] emitters have strong [OIII] emission lines. The [OIII]/[OII] ratios are
larger than normal star-forming galaxies in the local Universe, suggesting a
higher ionization parameter. Less massive galaxies have larger [OIII]/[OII]
ratios. With evidence that the electron density is consistent with local
galaxies, the high ionization of galaxies at high redshifts may be attributed
to a harder radiation field by a young stellar population and/or an increase in
the number of ionizing photons from each massive star.Comment: Fixed a minor issue with LaTeX table numberin
A Search for Molecular Gas toward a BzK-selected Star-forming Galaxy at z = 2.044
We present a search for CO(3-2) emission in SDF-26821, a BzK-selected
star-forming galaxy (sBzK) at z = 2.044, using the 45-m telescope of the
Nobeyama Radio Observatory and the Nobeyama Millimeter Array. We do not detect
significant emission and derive 2 \sigma limits: the CO luminosity of L'CO <
3.1 x 10^10 K km s^{-1} pc^{-2}, the ratio of far-infrared luminosity to CO
luminosity of L_FIR/L'CO > 57 Lsun (K km s^{-1} pc^{-2})^{-1}, and the
molecular gas mass of M_H2 < 2.5 x 10^10 Msun, assuming a velocity width of 200
km s^{-1} and a CO-to-H2 conversion factor of alpha_CO=0.8 Msun (K km s^{-1}
pc^{-2})^{-1}. The ratio of L_FIR/L'CO, a measure of star formation efficiency
(SFE), is comparable to or higher than the two z ~ 1.5 sBzKs detected in
CO(2-1) previously, suggesting that sBzKs can have a wide range of SFEs.
Comparisons of far-infrared luminosity, gas mass, and stellar mass among the
sBzKs suggest that SDF-26821 is at an earlier stage of forming stars with a
similar SFE and/or more efficiently forming stars than the two z ~ 1.5 sBzKs.
The higher SFEs and specific star formation rates of the sBzKs compared to
local spirals are indicative of the difference in star formation modes between
these systems, suggesting that sBzKs are not just scaled-up versions of local
spirals.Comment: 4 pages, 4 figures, Accepted for publication in PAS
A Census of Star-Forming Galaxies at z = 1-3 in the Subaru Deep Field
Several UV and near-infrared color selection methods have identified galaxies
at z = 1-3. Since each method suffers from selection biases, we have applied
three leading techniques (Lyman break, BX/BM, and BzK selection) simultaneously
in the Subaru Deep Field. This field has reliable ({\Delta}z/(1 + z) =
0.02--0.09) photometric redshifts for ~53,000 galaxies from 20 bands
(1500{\AA}--2.2{\mu}m). The BzK, LBG, and BX/BM samples suffer contamination
from z<1 interlopers of 6%, 8%, and 20%, respectively. Around the redshifts
where it is most sensitive (z~1.9 for star-forming BzK, z~1.8 for z~2 LBGs,
z~1.6 for BM, and z~2.3 for BX), each technique finds 60-80% of the census of
the three methods. In addition, each of the color techniques shares 75-96% of
its galaxies with another method, which is consistent with previous studies
that adopt identical criteria on magnitudes and colors. Combining the three
samples gives a comprehensive census that includes ~90% of z-phot = 1-3
galaxies, using standard magnitude limits similar to previous studies. In fact,
we find that among z = 1-2.5 galaxies in the color selection census, 81-90% of
them can be selected by just combining the BzK selection with one of the UV
techniques (z~2 LBG or BX and BM). The average galaxy stellar mass, reddening
and SFRs all decrease systematically from the sBzK population to the LBGs, and
to the BX/BMs. The combined color selections yield a total cosmic SFR density
of 0.18 0.03 M_sun yr^{-1} Mpc^{-3} for K_AB <= 24. We find that 65% of
the star formation is in galaxies with E(B-V) > 0.25 mag, even though they are
only one-fourth of the census by number.Comment: 26 pages, 30 figures, 9 tables, emulateapj format. Modified to match
the final ApJ versio
α-Tocopheryl succinate stabilizes the structure of tumor vessels by inhibiting angiopoietin-2 expression
α-Tocopheryl succinate (TS) is a tocopherol derivative and has multifaceted anti-cancer effects; TS not only causes cancer cell-specific apoptosis but also inhibits tumor angiogenesis. Although TS has the potential to be used as a well-tolerated anti-angiogenic drug, it is still unclear which step of the angiogenic process is inhibited by TS. Here, we show that TS inhibits the expression of angiopoietin (Ang)-2, which induces destabilization of vascular structure in the initial steps of the angiogenic process. In mouse melanoma cells, TS treatment decreased mRNA and extracellular protein levels of Ang-2; however, the mRNA level of Ang-1, which stabilizes the vascular structure, remained unchanged. Furthermore, aorta ring and Matrigel plug angiogenesis assays indicated that the conditioned medium from TS-treated cells (CM-TS) inhibited neovascularization and blood leakage from the existing blood vessels, respectively. Following immunohistochemical staining of the vessels treated with CM-TS, imaging studies showed that the vascular endothelial cells were highly packed with pericytes. In conclusion, we found that TS inhibits Ang-2 expression and, consequently, stabilizes the vascular structure during the initial step of tumor angiogenesis
Clinicopathological characteristics of patients with amyotrophic lateral sclerosis resulting in a totally locked-in state (communication Stage V)
In the present study, we performed a comprehensive analysis to clarify the clinicopathological characteristics of patients with amyotrophic lateral sclerosis (ALS) that had progressed to result in a totally locked-in state (communication Stage V), in which all voluntary movements are lost and communication is impossible. In 11 patients, six had phosphorylated TAR DNA-binding protein 43 (pTDP-43)-immunoreactive (ir) neuronal cytoplasmic inclusions (NCI), two had fused in sarcoma (FUS)-ir NCI, and three had copper/zinc superoxide dismutase (SOD1)-ir NCI. The time from ALS onset to the need for tracheostomy invasive ventilation was less than 24 months in ten patients. Regardless of accumulated protein, all the patients showed common lesions in the pallido-nigro-luysian system, brainstem reticular formation, and cerebellar efferent system, in addition to motor neurons. In patients with pTDP-43-ir NCI, patients with NCI in the hippocampal dentate granule neurons (DG) showed a neuronal loss in the cerebral cortex, and patients without NCI in DG showed a preserved cerebral cortex. By contrast, in patients with FUS-ir NCI, patients with NCI in DG showed a preserved cerebral cortex and patients without NCI in DG showed marked cerebral degeneration. The cerebral cortex of patients with SOD1-ir NCI was preserved. Together, these findings suggest that lesions of the cerebrum are probably not necessary for progression to Stage V. In conclusion, patients with ALS that had progressed to result in communication Stage V showed rapidly-progressed symptoms, and their common lesions could cause the manifestations of communication Stage V.ArticleACTA NEUROPATHOLOGICA COMMUNICATIONS.4:107(2016)journal articl
A Ly-alpha Emitter with an Extremely Large Rest-frame Equivalent Width of ~900A at z=6.5: A Candidate of Population III-dominated Galaxy?
We have identified a very interesting Ly-alpha emitter, whose Ly-alpha
emission line has an extremely large observed equivalent width of
EW_0=436^{+422}_{-149}A, which corresponds to an extraordinarily large
intrinsic rest-frame equivalent width of EW_0^{int}=872^{+844}_{-298}A after
the average intergalactic absorption correction. The object was
spectroscopically confirmed to be a real Ly-alpha emitter by its apparent
asymmetric Ly-alpha line profile detected at z=6.538. The continuum emission of
the object was definitely detected in our deep z'-band image; thus, its EW_0
was reliably determined. Follow-up deep near-infrared spectroscopy revealed
emission lines of neither He II lambda1640 as an apparent signature of
Population III, nor C IV lambda1549 as a proof of active nucleus. No detection
of short-lived He II lambda1640 line is not necessarily inconsistent with the
interpretation that the underlying stellar population of the object is
dominated by Population III. We found that the observed extremely large EW_0 of
the Ly-alpha emission and the upper limit on the EW_0 of the He II lambda1640
emission can be explained by population synthesis models favoring a very young
age less than 2-4Myr and massive metal-poor (Z<10^{-5}) or even metal-free
stars. The observed large EW_0 of Ly-alpha is hardly explained by Population
I/II synthesis models with Z>10^{-3}. However, we cannot conclusively rule out
the possibility that this object is composed of a normal stellar population
with a clumpy dust distribution, which could enhance the Ly-alpha EW_0, though
its significance is still unclear.Comment: 10 pages, 5 figures. Accepted for publication in Ap
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