419 research outputs found
Photospheric Abundances of Volatile and Refractory Elements in Planet-Harboring Stars
By using the high-dispersion spectra of 14 bright planet-harboring stars
(along with 4 reference stars) observed with the new coude echelle spectrograph
at Okayama Astrophysical Observatory, we investigated the abundances of
volatile elements (C, N, O, S, Zn; low condensation temperature Tc) in order to
examine whether these show any significant difference compared to the
abundances of other refractory elements (Si, Ti, V, Fe, Co, Ni; high Tc) which
are known to be generally overabundant in those stars with planets, since a
Tc-dependence is expected if the cause of such a metal-richness is due to the
accretion of solid planetesimals onto the host star. We found, however, that
all elements we studied behave themselves quite similarly to Fe (i.e.,
[X/Fe]~0) even for the case of volatile elements, which may suggest that the
enhanced metallicity in those planet-bearing stars is not so much an acquired
character (by accretion of rocky material) as rather primordial.Comment: 22 pages, 8 figures, to appear in PAS
Enantioselective reductive multicomponent coupling reactions between isatins and aldehydes
A reductive coupling of two different carbonyls via a polar two-electron reaction mechanism was developed and the stereochemical outcome of this multicomponent process is precisely controlled by a chiral triaminoiminophosphorane
The Hyper Suprime-Cam SSP Survey: Overview and Survey Design
Hyper Suprime-Cam (HSC) is a wide-field imaging camera on the prime focus of
the 8.2m Subaru telescope on the summit of Maunakea in Hawaii. A team of
scientists from Japan, Taiwan and Princeton University is using HSC to carry
out a 300-night multi-band imaging survey of the high-latitude sky. The survey
includes three layers: the Wide layer will cover 1400 deg in five broad
bands (), with a point-source depth of . The
Deep layer covers a total of 26~deg in four fields, going roughly a
magnitude fainter, while the UltraDeep layer goes almost a magnitude fainter
still in two pointings of HSC (a total of 3.5 deg). Here we describe the
instrument, the science goals of the survey, and the survey strategy and data
processing. This paper serves as an introduction to a special issue of the
Publications of the Astronomical Society of Japan, which includes a large
number of technical and scientific papers describing results from the early
phases of this survey.Comment: 14 pages, 7 figures, 5 tables. Corrected for a typo in the
coordinates of HSC-Wide spring equatorial field in Table
The infrared imaging spectrograph (IRIS) for TMT: status report for IRIS imager
The current status of IRIS imager at NAOJ is reported. IRIS (Infrared Imaging Spectrograph) is a first light instrument of TMT (Thirty Meter Telescope). IRIS has just passed the preliminary design review and moved forward to the final design phase. In this paper, optical and mechanical design of IRIS imager and prototyping activities conducted during the preliminary design phase are summarized
Sounding Rocket Experiment CLASP2: Development of the UV High-Precision Polarization Spectroscopy Device
Sounding Rocket Experiment CLASP2 (Chromospheric LAyer Spectro-Polarimeter-2): Development of the UV (Ultraviolet) High-Precision Polarization Spectroscopy Devic
A stochastic model of Echinococcus multilocularis transmission in Hokkaido, Japan, focusing on the infection process
Echinococcus multilocularis causes human alveolar echinococcus. In Japan, high prevalence of E. multilocularis among the fox population has been reported throughout Hokkaido. Accordingly, control measures, such as fox hunting and the distribution of bait containing Praziquantel, have been conducted. This study developed a transmission model for individuals in the fox population and included a stochastic infection process to assess the prevalence of E. multilocularis. To make our model realistic, we used the worm burden for each individual in the fox population. We assumed that the worm burden depends on the number of protoscoleces in a predated vole and the number of infection experiences. We carried out stochastic simulations with 1,000 trials for the situations of Koshimizu and Sapporo, Hokkaido, Japan. The distribution of the worm burden among foxes obtained using the model agreed with dissection data. The simulation indicates that a careful choice of season is necessary for an effective distribution of Praziquantel-containing bait. A stochastic model for E. multilocularis, which can assess the range of the prevalence in the fox population, would be helpful in analyzing their complex life-cycle and also in designing control strategies.</p
Synthesis, Conformation and Antiproliferative Activity of Isothiazoloisoxazole 1,1-dioxides
Sixteen new isothiazoloisoxazole 1,1-dioxides, one new isothiazolotriazole and one new isothiazolopyrazole have been synthesised by using 1,3-dipolar cycloadditions to isothiazole 1,1-dioxides. One sub-set of these isothiazoloisoxazoles showed low μM activity against a human breast carcinoma cell line, whilst a second sub-set plus the isothiazolotriazole demonstrated an interesting restricted rotation of sterically hindered bridgehead substituents. A thiazete 1,1-dioxide produced from one of the isothiazole 1,1-dioxides underwent conversion into an unknown 1,2,3-oxathiazolin-2-oxide upon treatment with Lewis acids, but was inert towards 1,3-dipoles and cyclopropenones. Six supporting crystal structures are included
Molybdenum (Mo) increases endogenous phenolics, proline and photosynthetic pigments and the phytoremediation potential of the industrially important plant Ricinus communis L. for removal of cadmium from contaminated soil.
Cadmium (Cd) in agricultural soil negatively affects crops yield and compromises food safety. Remediation of polluted soil is necessary for the re-establishment of sustainable agriculture and to prevent hazards to human health and environmental pollution. Phytoremediation is a promising technology for decontamination of polluted soil. The present study investigated the effect of molybdenum (Mo) (0.5, 1.0 and 2.0Â ppm) on endogenous production of total phenolics and free proline, plant biomass and photosynthetic pigments in Ricinus communis plants grown in Cd (25, 50 and 100Â ppm) contaminated soils and the potential for Cd phytoextraction. Mo was applied via seed soaking, soil addition and foliar spray. Foliar sprays significantly increased plant biomass, Cd accumulation and bioconcentration. Phenolic concentrations showed significantly positive correlations with Cd accumulation in roots (R 2Â =Â 0.793, 0.807 and 0.739) and leaves (R 2Â =Â 0.707, 721 and 0.866). Similarly, proline was significantly positively correlated with Cd accumulation in roots (R 2Â =Â 0.668, 0.694 and 0.673) and leaves (R 2Â =Â 0.831, 0.964 and 0.930). Foliar application was found to be the most effective way to deliver Mo in terms of increase in plant growth, Cd accumulation and production of phenolics and proline
DNA microarray revealed and RNAi plants confirmed key genes conferring low Cd accumulation in barley grains
List of genes down-regulated in both W6nk2 and Zhenong8 after 15 days exposure to 5 ΟM Cd. (DOC 130 kb
CLASP2: High-Precision Spectro-Polarimetery in Mg II h & k
The international team is promoting the CLASP2 (Chromospheric LAyer Spectro-Polarimeter 2) sounding rocket experiment, which is the re-flight of CLASP (2015). In this second flight, we will refit the existing CLASP instrument to measure all Stokes parameters in Mg II h k lines, and aim at inferring the magnetic field information in the upper chromosphere combining the Hanle and Zeeman effects. CLASP2 project was approved by NASA in December 2016, and is now scheduled to fly in 2019
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