653 research outputs found
Submillimeter Array Observation of the Proto-Planetary Nebula CRL 618 in the CO J=6-5 Line
We report on the results of a Submillimeter Array interferometric observation
of the proto-planetary nebula CRL 618 in the 12CO J=6-5 line. With the new
capability of SMA enabling us to use two receivers at a time, we also observed
simultaneously in the 12CO J=2-1 and 13CO J=2-1 lines. The 12CO J=6-5 and 13CO
J=2-1 lines were first interferometrically observed toward CRL 618. The flux of
the high velocity component of the 12CO J=6-5 line is almost fully recovered,
while roughly 80% of the flux of the low velocity component is resolved out.
The low recovery rate suggests that the emission region of the low velocity
component of the 12CO J=6-5 line is largely extended. Continuum emission is
detected both at 230 and 690 GHz. The flux of the 690 GHz continuum emission
seems to be partially resolved out, suggesting dust emission partly
contaminates the 690 GHz continuum flux. The cavity structure, which has been
confirmed in a previous observation in the 12CO J=2-1 line, is not clearly
detected in the 12CO J=6-5 line, and only the south wall of the cavity is
detected. This result suggests that the physical condition of the molecular
envelope of CRL 618 is not exactly axial symmetric.Comment: 24 pages, 9 figures, 1 table, accepted for publication in AJ. Full
resolution version available at
http://www.asiaa.sinica.edu.tw/~junichi/paper
High-Resolution Continuum Imaging at 1.3 and 0.7 cm of the W3 IRS 5 Region
High-resolution images of the hypercompact HII regions (HCHII) in W3 IRS 5
taken with the Very Large Array (VLA) at 1.3 and 0.7 cm are presented. Four
HCHII regions were detected with sufficient signal-to-noise ratios to allow the
determination of relevant parameters such as source position, size and flux
density. The sources are slightly extended in our ~0.2 arcsecond beams; the
deconvolved radii are less than 240 AU. A comparison of our data with VLA
images taken at epoch 1989.1 shows proper motions for sources IRS 5a and IRS
5f. Between 1989.1 and 2002.5, we find a proper motion of 210 mas at a position
angle of 12 deg for IRS 5f and a proper motion of 190 mas at a position angle
of 50 deg for IRS 5a. At the assumed distance to W3 IRS 5, 1.83 +/- 0.14 kpc,
these offsets translate to proper motions of ~135 km/s and ~122 km/s$
respectively. These sources are either shock ionized gas in an outflow or
ionized gas ejected from high mass stars. We find no change in the positions of
IRS 5d1/d2 and IRS 5b; and we show through a comparison with archival NICMOS
2.2 micron images that these two radio sources coincide with the infrared
double constituting W3 IRS 5. These sources contain B or perhaps O stars. The
flux densities of the four sources have changed compared to the epoch 1989.1
results. In our epoch 2002.5 data, none of the spectral indicies obtained from
flux densities at 1.3 and 0.7 cm are consistent with optically thin free-free
emission; IRS 5d1/d2 shows the largest increase in flux density from 1.3 cm to
0.7 cm. This may be an indication of free-free optical depth within an ionized
wind, a photoevaporating disk, or an accretion flow. It is less likely that
this increase is caused by dust emission at 0.7 cm.Comment: 13 pages, 3 figures To be published in The Astrophysical Journa
The IRAS galaxy 0421 + 040P06 - an active spiral (?) galaxy with extended radio lobes
The infrared bright galaxy 0421 + 040P06 detected by IRAS at 25 and 60 μm has been studied at optical, infrared, and radio wavelengths. It is a luminous galaxy with apparent spiral structure emitting 4 x 10^(37) W (1 x 10^(11) L_☉) from far-infrared to optical wavelengths, assuming H_0 = 75 km s^(-1) Mpc^(-1). Optical spectroscopy reveals a Seyfert 2 emission-line spectrum, making 0421 +040P06 the first active galaxy selected from an unbiased infrared survey of galaxies. The fact that this galaxy shows a flatter energy distribution with more 25 μm emission than other galaxies in the infrared sample may be related to the presence of an intense active nucleus. The radio observations reveal the presence of a nonthermal source that, at 6 cm, shows a prominent double lobed structure 20-30 kpc in size extending beyond the optical confines of the galaxy. The radio source is 3-10 times larger than structures previously seen in spiral galaxies and may represent a transition between the relatively small, weak sources seen in some active spirals and the stronger, larger ones seen toward elliptical galaxies with active nuclei
How accurate is patients' anatomical knowledge: a cross-sectional, questionnaire study of six patient groups and a general public sample
<p>Abstract</p> <p>Background</p> <p>Older studies have shown that patients often do not understand the terms used by doctors and many do not even have a rudimentary understanding of anatomy. The present study was designed to investigate the levels of anatomical knowledge of different patient groups and the general public in order to see whether this has improved over time and whether patients with a specific organ pathology (e.g. liver disease) have a relatively better understanding of the location of that organ.</p> <p>Methods</p> <p>Level of anatomical knowledge was assessed on a multiple-choice questionnaire, in a sample of 722 participants, comprising approximately 100 patients in each of 6 different diagnostic groups and 133 in the general population, using a between-groups, cross-sectional design. Comparisons of relative accuracy of anatomical knowledge between the present and earlier results, and across the clinical and general public groups were evaluated using Chi square tests. Associations with age and education were assessed with the Pearson correlation test and one-way analysis of variance, respectively.</p> <p>Results</p> <p>Across groups knowledge of the location of body organs was poor and has not significantly improved since an earlier equivalent study over 30 years ago (χ<sup>2 </sup>= 0.04, df = 1, ns). Diagnostic groups did not differ in their overall scores but those with liver disease and diabetes were more accurate regarding the location of their respective affected organs (χ<sup>2 </sup>= 18.10, p < 0.001, df = 1; χ<sup>2 </sup>= 10.75, p < 0.01, df = 1). Age was significantly negatively correlated (r = -0.084, p = 0.025) and education was positively correlated with anatomical knowledge (F = 12.94, p = 0.000). Although there was no overall gender difference, women were significantly better at identifying organs on female body outlines.</p> <p>Conclusion</p> <p>Many patients and general public do not know the location of key body organs, even those in which their medical problem is located, which could have important consequences for doctor-patient communication. These results indicate that healthcare professionals still need to take care in providing organ specific information to patients and should not assume that patients have this information, even for those organs in which their medical problem is located.</p
Submillimeter Emission from Water in the W3 Region
We have mapped the submillimeter emission from the 1(10)-1(01) transition of
ortho-water in the W3 star-forming region. A 5'x5' map of the W3 IRS4 and W3
IRS5 region reveals strong water lines at half the positions in the map. The
relative strength of the Odin lines compared to previous observations by SWAS
suggests that we are seeing water emission from an extended region. Across much
of the map the lines are double-peaked, with an absorption feature at -39 km/s;
however, some positions in the map show a single strong line at -43 km/s. We
interpret the double-peaked lines as arising from optically thick,
self-absorbed water emission near the W3 IRS5, while the narrower blue-shifted
lines originate in emission near W3 IRS4. In this model, the unusual appearance
of the spectral lines across the map results from a coincidental agreement in
velocity between the emission near W3 IRS4 and the blue peak of the more
complex lines near W3 IRS5. The strength of the water lines near W3 IRS4
suggests we may be seeing water emission enhanced in a photon-dominated region.Comment: Accepted to A&A Letters as part of the special Odin issue; 4 page
A 3D view of the outflow in the Orion Molecular Cloud 1 (OMC-1)
The fast outflow emerging from a region associated with massive star
formation in the Orion Molecular Cloud 1 (OMC-1), located behind the Orion
Nebula, appears to have been set in motion by an explosive event. Here we study
the structure and dynamics of outflows in OMC-1. We combine radial velocity and
proper motion data for near-IR emission of molecular hydrogen to obtain the
first 3-dimensional (3D) structure of the OMC-1 outflow. Our work illustrates a
new diagnostic tool for studies of star formation that will be exploited in the
near future with the advent of high spatial resolution spectro-imaging in
particular with data from the Atacama Large Millimeter Array (ALMA). We use
published radial and proper motion velocities obtained from the shock-excited
vibrational emission in the H2 v=1-0 S(1) line at 2.122 m obtained with
the GriF instrument on the Canada-France-Hawaii Telescope, the Apache Point
Observatory, the Anglo-Australian Observatory and the Subaru Telescope. These
data give the 3D velocity of ejecta yielding a 3D reconstruction of the
outflows. This allows one to view the material from different vantage points in
space giving considerable insight into the geometry. Our analysis indicates
that the ejection occurred <720 years ago from a distorted ring-like structure
of ~15" (6000 AU) in diameter centered on the proposed point of close encounter
of the stars BN, source I and maybe also source n. We propose a simple model
involving curvature of shock trajectories in magnetic fields through which the
origin of the explosion and the centre defined by extrapolated proper motions
of BN, I and n may be brought into spatial coincidence.Comment: Accepted for publication in Astronomy and Astrophysics (A&A), 12
pages, 9 figure
SN 2009kf : a UV bright type IIP supernova discovered with Pan-STARRS 1 and GALEX
We present photometric and spectroscopic observations of a luminous type IIP
Supernova 2009kf discovered by the Pan-STARRS 1 (PS1) survey and detected also
by GALEX. The SN shows a plateau in its optical and bolometric light curves,
lasting approximately 70 days in the rest frame, with absolute magnitude of M_V
= -18.4 mag. The P-Cygni profiles of hydrogen indicate expansion velocities of
9000km/s at 61 days after discovery which is extremely high for a type IIP SN.
SN 2009kf is also remarkably bright in the near-ultraviolet (NUV) and shows a
slow evolution 10-20 days after optical discovery. The NUV and optical
luminosity at these epochs can be modelled with a black-body with a hot
effective temperature (T ~16,000 K) and a large radius (R ~1x10^{15} cm). The
bright bolometric and NUV luminosity, the lightcurve peak and plateau duration,
the high velocities and temperatures suggest that 2009kf is a type IIP SN
powered by a larger than normal explosion energy. Recently discovered high-z
SNe (0.7 < z < 2.3) have been assumed to be IIn SNe, with the bright UV
luminosities due to the interaction of SN ejecta with a dense circumstellar
medium (CSM). UV bright SNe similar to SN 2009kf could also account for these
high-z events, and its absolute magnitude M_NUV = -21.5 +/- 0.5 mag suggests
such SNe could be discovered out to z ~2.5 in the PS1 survey.Comment: Accepted for publication in APJ
Heavy nuclei at the end of the cosmic ray spectrum?
We provide an account of the possible acceleration of iron nuclei up to
energies EeV in the nearby, metally-rich starburst galaxy NGC 253. It
is suggested that particles can escape from the nuclear region with energies of
eV and then could be reaccelerated at the terminal shock of the
galactic superwind generated by the starburst, avoiding in this way the
photodisintegration expected if the nuclei were accelerated in the central
region of high photon density. We have also made estimates of the expected
arrival spectrum, which displays a strong dependency with the energy cutoff at
the source.Comment: Revised version, to appear in Physical Review
Differential Ly-6C expression identifies the recruited macrophage phenotype, which orchestrates the regression of murine liver fibrosis
Although macrophages are widely recognized to have a profibrotic role in inflammation, we have used a highly tractable CCl(4)-induced model of reversible hepatic fibrosis to identify and characterize the macrophage phenotype responsible for tissue remodeling: the hitherto elusive restorative macrophage. This CD11B(hi) F4/80(int) Ly-6C(lo) macrophage subset was most abundant in livers during maximal fibrosis resolution and represented the principle matrix metalloproteinase (MMP) -expressing subset. Depletion of this population in CD11B promoter–diphtheria toxin receptor (CD11B-DTR) transgenic mice caused a failure of scar remodeling. Adoptive transfer and in situ labeling experiments showed that these restorative macrophages derive from recruited Ly-6C(hi) monocytes, a common origin with profibrotic Ly-6C(hi) macrophages, indicative of a phenotypic switch in vivo conferring proresolution properties. Microarray profiling of the Ly-6C(lo) subset, compared with Ly-6C(hi) macrophages, showed a phenotype outside the M1/M2 classification, with increased expression of MMPs, growth factors, and phagocytosis-related genes, including Mmp9, Mmp12, insulin-like growth factor 1 (Igf1), and Glycoprotein (transmembrane) nmb (Gpnmb). Confocal microscopy confirmed the postphagocytic nature of restorative macrophages. Furthermore, the restorative macrophage phenotype was recapitulated in vitro by the phagocytosis of cellular debris with associated activation of the ERK signaling cascade. Critically, induced phagocytic behavior in vivo, through administration of liposomes, increased restorative macrophage number and accelerated fibrosis resolution, offering a therapeutic strategy to this orphan pathological process
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