157 research outputs found
On Hadronic Production of the Meson
Two of the approaches to the hadronic productions of the double heavy mesons
and are investigated. Comparison in various aspects on the
results obtained by the approaches is made and shown in figures and a table.
Some trial understanding of the approaches themselves and the achieved results
is presented. The results may be used as some references for discovering the
mesons at Tevatron and LHC.Comment: 18 pages, the revised version of hep-ph/940824
Local Magnetic Field Role in Star Formation
We highlight distinct and systematic observational features of magnetic field
morphologies in polarized submm dust continuum. We illustrate this with
specific examples and show statistical trends from a sample of 50 star-forming
regions.Comment: 4 pages, 3 figures; to appear in the EAS Proceedings of the 6th
Zermatt ISM Symposium "Conditions and Impact of Star Formation from Lab to
Space", September 201
Intensity modulated radiotherapy for elderly bladder cancer patients
<p>Abstract</p> <p>Background</p> <p>To review our experience and evaluate treatment planning using intensity-modulated radiotherapy (IMRT) and helical tomotherapy (HT) for the treatment of elderly patients with bladder cancer.</p> <p>Methods</p> <p>From November 2006 through November 2009, we enrolled 19 elderly patients with histologically confirmed bladder cancer, 9 in the IMRT and 10 in the HT group. The patients received 64.8 Gy to the bladder with or without concurrent chemotherapy. Conventional 4-field "box" pelvic radiation therapy (2DRT) plans were generated for comparison.</p> <p>Results</p> <p>The median patient age was 80 years old (range, 65-90 years old). The median survival was 21 months (5 to 26 months). The actuarial 2-year overall survival (OS) for the IMRT vs. the HT group was 26.3% <it>vs </it>.37.5%, respectively; the corresponding values for disease-free survival were 58.3% <it>vs</it>. 83.3%, respectively; for locoregional progression-free survival (LRPFS), the values were 87.5% <it>vs</it>. 83.3%, respectively; and for metastases-free survival, the values were 66.7% <it>vs</it>. 60.0%, respectively. The 2-year OS rates for T1, 2 <it>vs</it>. T3, 4 were 66.7% <it>vs</it>. 35.4%, respectively (<it>p </it>= 0.046). The 2-year OS rate was poor for those whose RT completion time greater than 8 weeks when compared with the RT completed within 8 wks (37.9% vs. 0%, <it>p </it>= 0.004).</p> <p>Conclusion</p> <p>IMRT and HT provide good LRPFS with tolerable toxicity for elderly patients with invasive bladder cancer. IMRT and HT dosimetry and organ sparing capability were superior to that of 2DRT, and HT provides better sparing ability than IMRT. The T category and the RT completion time influence OS rate.</p
Early Planet Formation in Embedded Disks (eDisk) X: Compact Disks, Extended Infall, and a Fossil Outburst in the Class I Oph IRS43 Binary
We present the first results from the Early Planet Formation in Embedded
Disks (eDisk) ALMA Large Program toward Oph IRS43, a binary system of solar
mass protostars. The 1.3 mm dust continuum observations resolve a compact disk,
~6au radius, around the northern component and show that the disk around the
southern component is even smaller, <~3 au. CO, 13CO, and C18O maps reveal a
large cavity in a low mass envelope that shows kinematic signatures of rotation
and infall extending out to ~ 2000au. An expanding CO bubble centered on the
extrapolated location of the source ~130 years ago suggests a recent outburst.
Despite the small size of the disks, the overall picture is of a remarkably
large and dynamically active region.Comment: Paper 10 of the ALMA eDisk Large Program. Accepted for publication in
Ap
Early Planet Formation in Embedded Disks (eDisk). VIII. A Small Protostellar Disk around the Extremely Low-Mass and Young Class 0 Protostar, IRAS 15398-3359
Protostellar disks are a ubiquitous part of the star formation process and
the future sites of planet formation. As part of the Early Planet Formation in
Embedded Disks (eDisk) large program, we present high-angular resolution dust
continuum (mas) and molecular line (mas) observations of
the Class 0 protostar, IRAS 15398-3359. The dust continuum is small, compact,
and centrally peaked, while more extended dust structures are found in the
outflow directions. We perform a 2D Gaussian fitting to find the deconvolved
size and radius of the dust disk to be
and , respectively. We estimate the gas+dust disk mass
assuming optically thin continuum emission to be ,
indicating a very low-mass disk. The CO isotopologues trace components of the
outflows and inner envelope, while SO traces a compact, rotating disk-like
component. Using several rotation curve fittings on the PV diagram of the SO
emission, the lower limits of the protostellar mass and gas disk radius are
and from our Modified 2 single power-law
fitting. A conservative upper limit of the protostellar mass is inferred to be
. The protostellar mass-accretion rate and the specific angular
momentum at the protostellar disk edge are found to be between
and
, respectively, with an age
estimated between yr. At this young age with no clear
substructures in the disk, planet formation would likely not yet have started.
This study highlights the importance of high-resolution observations and
systematic fitting procedures when deriving dynamical properties of deeply
embedded Class 0 protostars.Comment: 28 pages, 16 figures. Accepted for publication in ApJ as one of the
first-look papers of the eDisk ALMA Large Progra
Early Planet Formation in Embedded Disks (eDisk) VI: Kinematic Structures around the Very Low Mass Protostar IRAS 16253-2429
Precise estimates of protostellar masses are crucial to characterize the
formation of stars of low masses down to brown-dwarfs (BDs; M* < 0.08 Msun).
The most accurate estimation of protostellar mass uses the Keplerian rotation
in the circumstellar disk around the protostar. To apply the Keplerian rotation
method to a protostar at the low-mass end, we have observed the Class 0
protostar IRAS 16253-2429 using the Atacama Large Millimeter/submillimeter
Array (ALMA) in the 1.3 mm continuum at an angular resolution of 0.07" (10 au),
and in the 12CO, C18O, 13CO (J=2-1), and SO (J_N = 6_5-5_4) molecular lines, as
part of the ALMA Large Program Early Planet Formation in Embedded Disks
(eDisk). The continuum emission traces a non-axisymmetric, disk-like structure
perpendicular to the associated 12CO outflow. The position-velocity (PV)
diagrams in the C18O and 13CO lines can be interpreted as infalling and
rotating motions. In contrast, the PV diagram along the major axis of the
disk-like structure in the 12CO line allows us to identify Keplerian rotation.
The central stellar mass and the disk radius are estimated to be ~0.12-0.17
Msun and ~13-19 au, respectively. The SO line suggests the existence of an
accretion shock at a ring (r~28 au) surrounding the disk and a streamer from
the eastern side of the envelope. IRAS 16253-2429 is not a proto-BD but has a
central stellar mass close to the BD mass regime, and our results provide a
typical picture of such very low-mass protostars.Comment: 41 pages, 14 figure
Early Planet Formation in Embedded Disks (eDisk) V: Possible Annular Substructure in a Circumstellar Disk in the Ced110 IRS4 System
We have observed the Class 0/I protostellar system Ced110 IRS4 at an angular
resolution of (10 au) as a part of the ALMA large program; Early
Planet Formation in the Embedded Disks (eDisk). The 1.3 mm dust continuum
emission reveals that Ced110 IRS4 is a binary system with a projected
separation of 250 au. The continuum emissions associated with the main
source and its companion, named Ced110 IRS4A and IRS4B respectively, exhibit
disk-like shapes and likely arise from dust disks around the protostars. The
continuum emission of Ced110 IRS4A has a radius of 110 au (),
and shows bumps along its major axis with an asymmetry. The bumps can be
interpreted as an shallow, ring-like structure at a radius of 40 au
() in the continuum emission, as demonstrated from two-dimensional
intensity distribution models. A rotation curve analysis on the CO and
CO -1 lines reveals the presence of a Keplerian disk within a
radius of 120 au around Ced110 IRS4A, which supports the interpretation that
the dust continuum emission arises from a disk. The ring-like structure in the
dust continuum emission might indicate a possible, annular substructure in the
surface density of the embedded disk, although the possibility that it is an
apparent structure due to the optically thick continuum emission cannot be
ruled out.Comment: 32 pages, 23 figures. Accepted for publication in ApJ as one of the
first-look papers of the eDisk ALMA Large Progra
Early Planet Formation in Embedded Disks (eDisk). II. Limited Dust Settling and Prominent Snow Surfaces in the Edge-on Class I Disk IRAS 04302+2247
While dust disks around optically visible, Class II protostars are found to
be vertically thin, when and how dust settles to the midplane are unclear. As
part of the Atacama Large Millimeter/submillimeter Array (ALMA) large program,
Early Planet Formation in Embedded Disks, we analyze the edge-on, embedded,
Class I protostar IRAS 04302+2247, also nicknamed the ``Butterfly Star." With a
resolution of 0.05" (8~au), the 1.3 mm continuum shows an asymmetry along the
minor axis which is evidence of an optically thick and geometrically thick disk
viewed nearly edge-on. There is no evidence of rings and gaps, which could be
due to the lack of radial substructure or the highly inclined and optically
thick view. With 0.1" (16~au) resolution, we resolve the 2D snow surfaces,
i.e., the boundary region between freeze-out and sublimation, for CO
=2--1, CO =2--1, CO =2--1, CO
=--, and SO =--, and constrain the CO
midplane snow line to au. We find Keplerian rotation around a
protostar of using CO. Through forward
ray-tracing using RADMC-3D, we find that the dust scale height is au
at a radius of 100~au from the central star and is comparable to the gas
pressure scale height. The results suggest that the dust of this Class~I source
has yet to vertically settle significantly.Comment: 33 pages, 21 figures. Accepted for publication in ApJ as one of the
first-look papers of the eDisk ALMA Large Progra
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