1,871 research outputs found
Aligned Molecular Clouds towards SS433 and L=348.5 degrees; Possible Evidence for Galactic "Vapor Trail" Created by Relativistic Jet
We have carried out a detailed analysis of the NANTEN 12CO(J=1-0) dataset in
two large areas of ~25 square degrees towards SS433 (l~40 degree) and of ~18
square degrees towards l~348.5 degree, respectively. We have discovered two
groups of remarkably aligned molecular clouds at |b|~1--5 degree in the two
regions. In SS433, we have detected 10 clouds in total, which are well aligned
nearly along the axis of the X-ray jet emanating from SS433. These clouds have
similar line-of-sight velocities of 42--56 km s^-1 and the total projected
length of the feature is ~300 pc, three times larger than that of the X-ray
jet, at a distance of 3 kpc. Towards l~348.5 degree, we have detected four
clouds named as MJG348.5 at line-of-sight velocities of -80 -- -95 km s^-1 in
V_LSR, which also show alignment nearly perpendicular to the Galactic plane.
The total length of the feature is ~400 pc at a kinematic distance of 6 kpc. In
the both cases, the CO clouds are distributed at high galactic latitudes where
such clouds are very rare. In addition, their alignments and coincidence in
velocity should be even rarer, suggesting that they are physically associated.
We tested a few possibilities to explain these clouds, including protostellar
outflows, supershells, and interactions with energetic jets. Among them, a
favorable scenario is that the interaction between relativistic jet and the
interstellar medium induced the formation of molecular clouds over the last
~10^5-6 yrs. It is suggested that the timescale of the relativistic jet may be
considerably larger, in the order of 10^5-6 yrs, than previously thought in
SS433. The driving engine of the jet is obviously SS433 itself in SS433,
although the engine is not yet identified in MJG348.5 among possible several
candidates detected in the X-rays and TeV gamma rays.Comment: 29 pages, 10 figures, already published in PASJ, 2008,60, 71
Most of the VP1 Unique Region of B19 Parvovirus Is on the Capsid Surface
AbstractB19 parvovirus is pathogenic in man and a vaccine is desirable. In convalescence after acute infection, the dominant humoral immune response is directed to the minor capsid protein called VP1, which differs from the major capsid protein by an additional NH2-terminal 227 amino acids. We have previously shown that this unique region contains multiple linear neutralizing epitopes. We produced seven recombinant B19 capsids that contained progressively truncated VP1 unique region sequences, each fused to a Flag peptide (AspTyrLysAspAspAspAspLys) at the NH2-terminus. Capsids containing normal VP2 and truncated Flag-VP1 proteins and, in some cases, only truncated Flag-VP1 chimeric proteins, were analyzed by ELISA, affinity chromatography, and electron microscopy using anti-Flag monoclonal antibody. All regions examined showed binding to anti-Flag antibody in multiple assays, indicating that most of the VP1 unique region is external to the capsid and accessible to antibody binding. These results have implications for the design of a B19 parvovirus vaccine and the use of empty capsids for presentation of heterologous protein antigens
Finite element analysis of magnetic circuits composed of axisymmetric and rectangular regions
A new approximate method is developed for calculating three-dimensional magnetic fields in magnetic circuits composed of connected axisymmetric and rectangular regions. Using this new method, fairly accurate solutions can be obtained when the leakage flux from the magnetic circuit is small. In this paper, the new method is explained and then the usefulness of the technique is clarified by comparing calculated and measured flux densities.</p
Terahertz generation in Czochralski grown periodically poled Mg:Y:LiNbO3 via optical rectification
Using a canonical pump-probe experimental technique, we studied the terahertz
(THz) waves generation and detection via optical rectification and mixing in
Czochralski-grown periodically poled Mg:Y:LiNbO3 (PPLN) crystals. THz waves
with frequencies at 1.37 THz and 0.68 THz as well as 1.8 THz were obtained for
PPLN with nonlinear grating periods of 0.03 and 0.06 mm, respectively. A
general theoretical model was developed by considering the dispersion and
damping of low frequency phonon-polariton mode. Our results show that THz waves
are generated in forward and backward directions via pumping pulse
rectification. The generated THz waves depend on the spectral shape of the
laser pulses, quasi-phase mismatches and dispersion characteristics of a
crystal.Comment: 25 pages, 4 figure
Understanding Malicious Behavior in Crowdsourcing Platforms: The Case of Online Surveys.
Crowdsourcing is increasingly being used as a means to tackle problems requiring human intelligence. With the ever-growing worker base that aims to complete microtasks on crowdsourcing platforms in exchange for financial gains, there is a need for stringent mechanisms to prevent exploitation of deployed tasks. Quality control mechanisms need to accommodate a diverse pool of workers, exhibiting a wide range of behavior. A pivotal step towards fraud-proof task design is understanding the behavioral patterns of microtask workers. In this paper, we analyze the prevalent malicious activity on crowdsourcing platforms and study the behavior exhibited by trustworthy and untrustworthy workers, particularly on crowdsourced surveys. Based on our analysis of the typical malicious activity, we define and identify different types of workers in the crowd, propose a method to measure malicious activity, and finally present guidelines for the efficient design of crowdsourced surveys
Isotopic dependence of the giant monopole resonance in the even-A ^{112-124}Sn isotopes and the asymmetry term in nuclear incompressibility
The strength distributions of the giant monopole resonance (GMR) have been
measured in the even-A Sn isotopes (A=112--124) with inelastic scattering of
400-MeV particles in the angular range
--. We find that the experimentally-observed GMR energies
of the Sn isotopes are lower than the values predicted by theoretical
calculations that reproduce the GMR energies in Pb and Zr very
well. From the GMR data, a value of MeV is obtained
for the asymmetry-term in the nuclear incompressibility.Comment: Submitted to Physical Review Letters. 10 pages; 4 figure
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