876 research outputs found
Molecular Clouds associated with the Type Ia SNR N103B in the Large Magellanic Cloud
N103B is a Type Ia supernova remnant (SNR) in the Large Magellanic Cloud
(LMC). We carried out new CO( = 3-2) and CO( = 1-0)
observations using ASTE and ALMA. We have confirmed the existence of a giant
molecular cloud (GMC) at 245 km s towards the
southeast of the SNR using ASTE CO( = 3-2) data at an angular
resolution of 25 (6 pc in the LMC). Using the ALMA CO(
= 1-0) data, we have spatially resolved CO clouds along the southeastern edge
of the SNR with an angular resolution of 1.8 (0.4 pc in the
LMC). The molecular clouds show an expanding gas motion in the
position-velocity diagram with an expansion velocity of km s.
The spatial extent of the expanding shell is roughly similar to that of the
SNR. We also find tiny molecular clumps in the directions of optical nebula
knots. We present a possible scenario that N103B exploded in the wind-bubble
formed by the accretion winds from the progenitor system, and is now
interacting with the dense gas wall. This is consistent with a
single-degenerate scenario.Comment: 12 pages, 1 table, 8 figures, accepted for publication in The
Astrophysical Journal (ApJ
ALMA CO Observations of Supernova Remnant N63A in the Large Magellanic Cloud: Discovery of Dense Molecular Clouds Embedded within Shock-Ionized and Photoionized Nebulae
We carried out new CO( = 1-0, 3-2) observations of a N63A supernova
remnant (SNR) from the LMC using ALMA and ASTE. We find three giant molecular
clouds toward the northeast, east, and near the center of the SNR. Using the
ALMA data, we spatially resolved clumpy molecular clouds embedded within the
optical nebulae in both the shock-ionized and photoionized lobes discovered by
previous H and [S II] observations. The total mass of the molecular
clouds is for the shock-ionized region and
for the photoionized region. Spatially resolved X-ray spectroscopy
reveals that the absorbing column densities toward the molecular clouds are
- cm, which are - times less
than the averaged interstellar proton column densities for each region. This
means that the X-rays are produced not only behind the molecular clouds, but
also in front of them. We conclude that the dense molecular clouds have been
completely engulfed by the shock waves, but have still survived erosion owing
to their high-density and short interacting time. The X-ray spectrum toward the
gas clumps is well explained by an absorbed power-law or high-temperature
plasma models in addition to the thermal plasma components, implying that the
shock-cloud interaction is efficiently working for both the cases through the
shock ionization and magnetic field amplification. If the hadronic gamma-ray is
dominant in the GeV band, the total energy of cosmic-ray protons is calculated
to be - erg with the estimated ISM proton density
of cm, containing both the shock-ionized gas and
neutral atomic hydrogen.Comment: 18 pages, 4 tables, 8 figures, accepted for publication in The
Astrophysical Journal (ApJ
Experimental Measurement of the Persistence Exponent of the Planar Ising Model
Using a twisted nematic liquid crystal system exhibiting planar Ising model
dynamics, we have measured the scaling exponent which characterizes
the time evolution, , of the probability p(t) that the
local order parameter has not switched its state by the time t. For 0.4 seconds
to 200 seconds following the phase quench, the system exhibits scaling behavior
and, measured over this interval, , in good agreement
with theoretical analysis and numerical simulations.Comment: 4 pages RevTeX (multicol.sty and epsf.sty needed): 1 EPS figure.
Introduction and reference list modifie
DOWN-REGULATION OF SREBP-1C IS ASSOCIATED WITH THE DEVELOPMENT OF BURNED-OUT NASH
Abstracts of the International Liver Congress™ 2010 – the 45th annual meeting of the European Association for the Study of the Liver (EASL)ArticleJOURNAL OF HEPATOLOGY. 52(Suppl. 1):S373-S374 (2010)conference pape
Atrial natriuretic peptide and three-dimensional echocardiography after transcatheter closure of atrial septal defect
<p>Abstract</p> <p>Background</p> <p>Atrial septal defect (ASD) accounts for 10% of all congenital heart lesions and represent the third most congenital cardiac defect seen in adults. Atrial natriuretic peptide (ANP) is an important regulator of the sodium and volume homeostasis. This study was designed to investigate the changes in plasma ANP concentrations and three-dimensional echocardiography (3DE) measurements of cardiac volume in patients with ASD during transcatheter closure of defect.</p> <p>Methods</p> <p>Plasma ANP concentrations and transthoracic 3DE measurements of right ventricular volume were performed in 46 patients with ASD before closure, and at 3 days after closure. 22 healthy subjects matched for age, sex served as control subjects.</p> <p>Results</p> <p>The 46 patients (20 men, 26 women; mean age 26.32 ± 13.28, range 6 to 63 years) were diagnosed to secundum ASD (the stretched diameters of ASD were from 9~36(25.34 ± 7.80 mm), and had been successfully placed Amplatzer septal occluder (the sizes of occluder were from 11 to 40 mm). The results showed that compared with control subjects, plasma ANP concentrations were elevated in patients with ASD. Plasma ANP concentrations positively correlated significantly with pulmonary artery pressure (PAP) (r = 0.74, <it>p </it>< 0.05) and 3DE measurements of cardiac volumes (right ventricular end-diastolic (r = 0.50, <it>p </it>< 0.05) and end-systolic volume (r = 0.50, <it>p </it>< 0.05) and negatively correlated with RVEF (r = -0.38, <it>p </it>< 0.05). Transthoracic 3DE measurements of right ventricular volume and plasma ANP concentrations decreased significantly at 3 days after closure (<it>p </it>< 0.05) compared with it before closure.</p> <p>Conclusion</p> <p>Plasma ANP concentrations were markedly elevated in patients with pulmonary arterial hypertension and right ventricular volume overload and decreased significantly after closure of ASD. This study suggested that ANP may help to identify patients with ASD complicated by pulmonary arterial hypertension and right ventricular volume overload that demanded early intervention and may become effective marker for evaluating changes in cardiac load after transcatheter ASD closure.</p
Selective excitation of metastable atomic states by femto- and attosecond laser pulses
The possibility of achieving highly selective excitation of low metastable
states of hydrogen and helium atoms by using short laser pulses with reasonable
parameters is demonstrated theoretically. Interactions of atoms with the laser
field are studied by solving the close-coupling equations without
discretization. The parameters of laser pulses are calculated using different
kinds of optimization procedures. For the excitation durations of hundreds of
femtoseconds direct optimization of the parameters of one and two laser pulses
with Gaussian envelopes is used to introduce a number of simple schemes of
selective excitation. To treat the case of shorter excitation durations,
optimal control theory is used and the calculated optimal fields are
approximated by sequences of pulses with reasonable shapes. A new way to
achieve selective excitation of metastable atomic states by using sequences of
attosecond pulses is introduced.Comment: To be published in Phys. Rev. A, 10 pages, 3 figure
- …