1,029 research outputs found
Bis(5,6-dicarboxybenzimidazolium) sulfate monohydrate
In the title compound, 2C9H7N2O4
+·SO4
2−·H2O, the sulfate S atom and the water O atom reside on a crystallographic twofold axis. In the crystal, the component species are linked by N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds, forming a three-dimensional network structure. An intramolecular O—H⋯O link is seen in the cation
Winter longitudinal variation in the body size of larval fishes in the Seto Inland Sea, Japan
This study revealed the spatial variation in abun-dance and body size of larval fishes in the Seto Inland Sea, Japan, in January 2014 and 2015. Fish larvae were col-lected by a 1.3-m-diameter ring net towed at the surface and at 10-m depth at 21 stations. The most dominant spe-cies was the sandlance Ammodytes japonicus, constituting 82% of total larval fish caught. The body size of A. japoni-cus was greater [ca. 9 mm total length (TL) in 2014] in eastern areas than in western areas (ca. 5 mm TL in 2014). This trend was also observed in rockfishes (Sebastiscus marmoratus and Sebastes inermis species complex), sug-gesting a common phenomenon in this region. Because the water temperature was lower in eastern areas, it is likely that the longitudinal differences in larval body size are attributable to earlier spawning in eastern areas caused by different temperature conditions.This work was partly supported by the Environment Research and Technology Development Fund (S-13) granted by the Ministry of the Environment, Japan.Electronic supplementary material: The online version of this article (doi:10.1007/s12562-017-1076-2) contains supplementary material, which is available to authorized users.アクセプト後にアブストラクト・キーワードの変更あり
Astrometry of Water Maser Sources in Nearby Molecular Clouds with VERA - II. SVS 13 in NGC 1333
We report on the results of multi-epoch VLBI observations with VERA (VLBI
Exploration of Radio Astrometry) of the 22 GHz H2O masers associated with the
young stellar object SVS 13 in the NGC 1333 region. We have carried out
phase-referencing VLBI astrometry and measured an annual parallax of the maser
features in SVS 13 of 4.25+/-0.32 mas, corresponding to the distance of
235+/-18 pc from the Sun. Our result is consistent with a photometric distance
of 220 pc previously reported. Even though the maser features were detectable
only for 6 months, the present results provide the distance to NGC 1333 with
much higher accuracy than photometric methods. The absolute positions and
proper motions have been derived, revealing that the H2O masers with the LSR
(local standard of rest) velocities of 7-8 km s-1 are most likely associated
with VLA4A, which is a radio counterpart of SVS 13. The origin of the observed
proper motions of the maser features are currently difficult to attribute to
either the jet or the rotating circumstellar disk associated with VLA4A, which
should be investigated through future high-resolution astrometric observations
of VLA4A and other radio sources in NGC 1333.Comment: 9 pages, 5 figures. PASJ, in press (2008, Vol. 60, No. 1
Perturbation Theory in Two Dimensional Open String Field Theory
In this paper we develop the covariant string field theory approach to open
2d strings. Upon constructing the vertices, we apply the formalism to calculate
the lowest order contributions to the 4- and 5- point tachyon--tachyon tree
amplitudes. Our results are shown to match the `bulk' amplitude calculations of
Bershadsky and Kutasov. In the present approach the pole structure of the
amplitudes becomes manifest and their origin as coming from the higher string
modes transparent.Comment: 26 page
Astrometry of Galactic Star Forming Region Sharpless 269 with VERA : Parallax Measurements and Constraint on Outer Rotation Curve
We have performed high-precision astrometry of H2O maser sources in Galactic
star forming region Sharpless 269 (S269) with VERA. We have successfully
detected a trigonometric parallax of 189+/-8 micro-arcsec, corresponding to the
source distance of 5.28 +0.24/-0.22 kpc. This is the smallest parallax ever
measured, and the first one detected beyond 5 kpc. The source distance as well
as proper motions are used to constrain the outer rotation curve of the Galaxy,
demonstrating that the difference of rotation velocities at the Sun and at S269
(which is 13.1 kpc away from the Galaxy's center) is less than 3%. This gives
the strongest constraint on the flatness of the outer rotation curve and
provides a direct confirmation on the existence of large amount of dark matter
in the Galaxy's outer disk.Comment: 7 pages and 4 figures, Accepted by PASJ (Vol. 59, No. 5, October 25,
2007 issue
Distance to Orion KL Measured with VERA
We present the initial results of multi-epoch VLBI observations of the 22 GHz
H2O masers in the Orion KL region with VERA (VLBI Exploration of Radio
Astrometry). With the VERA dual-beam receiving system, we have carried out
phase-referencing VLBI astrometry and successfully detected an annual parallax
of Orion KL to be 2.29+/-0.10 mas, corresponding to the distance of 437+/-19 pc
from the Sun. The distance to Orion KL is determined for the first time with
the annual parallax method in these observations. Although this value is
consistent with that of the previously reported, 480+/-80 pc, which is
estimated from the statistical parallax method using proper motions and radial
velocities of the H2O maser features, our new results provide the much more
accurate value with an uncertainty of only 4%. In addition to the annual
parallax, we have detected an absolute proper motion of the maser feature,
suggesting an outflow motion powered by the radio source I along with the
systematic motion of source I itself.Comment: 7 pages, 3 figures. PASJ, in press (Vol. 59, No. 5, October 25, 2007
issue
Global Monopole in General Relativity
We consider the gravitational properties of a global monopole on the basis of
the simplest Higgs scalar triplet model in general relativity. We begin with
establishing some common features of hedgehog-type solutions with a regular
center, independent of the choice of the symmetry-breaking potential. There are
six types of qualitative behavior of the solutions; we show, in particular,
that the metric can contain at most one simple horizon. For the standard
Mexican hat potential, the previously known properties of the solutions are
confirmed and some new results are obtained. Thus, we show analytically that
solutions with monotonically growing Higgs field and finite energy in the
static region exist only in the interval , being the
squared energy of spontaneous symmetry breaking in Planck units. The
cosmological properties of these globally regular solutions apparently favor
the idea that the standard Big Bang might be replaced with a nonsingular static
core and a horizon appearing as a result of some symmetry-breaking phase
transition on the Planck energy scale. In addition to the monotonic solutions,
we present and analyze a sequence of families of new solutions with oscillating
Higgs field. These families are parametrized by , the number of knots of the
Higgs field, and exist for ; all such
solutions possess a horizon and a singularity beyond it.Comment: 14 pages, 8 figure
Absolute Proper Motions of H2O Masers Away from the Galactic Plane Measured with VERA in the "Superbubble" Region NGC 281
We report on absolute proper-motion measurements of an H2O maser source in
the NGC 281 West molecular cloud, which is located ~320 pc above the Galactic
plane and is associated with an HI loop extending from the Galactic plane. We
have conducted multi-epoch phase-referencing observations of the maser source
with VERA (VLBI Exploration of Radio Astrometry) over a monitoring period of 6
months since May 2006. We find that the H2O maser features in NGC 281 West are
systematically moving toward the southwest and further away from the Galactic
plane with a vertical velocity of ~20-30 km/s at its estimated distance of
2.2-3.5 kpc. Our new results provide the most direct evidence that the gas in
the NGC 281 region on the HI loop was blown out from the Galactic plane, most
likely in a superbubble driven by multiple or sequential supernova explosions
in the Galactic plane.Comment: 10 pages, 5 figures, PASJ in press (Vol. 59, No. 4; August 25, 2007
issue
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