579 research outputs found
Phase-reference VLBI Observations of the Compact Steep-Spectrum Source 3C 138
We investigate a phase-reference VLBI observation that was conducted at 15.4
GHz by fast switching VLBA antennas between the compact steep-spectrum radio
source 3C 138 and the quasar PKS 0528+134 which are about 4 away on the
sky. By comparing the phase-reference mapping with the conventional hybrid
mapping, we demonstrate the feasibility of high precision astrometric
measurements for sources separated by 4. VLBI phase-reference mapping
preserves the relative phase information, and thus provides an accurate
relative position between 3C 138 and PKS 0528+134 of
and
(J2000.0) in right ascension and declination, respectively. This gives an
improved position of the nucleus (component A) of 3C 138 in J2000.0 to be
RA= and Dec= under the
assumption that the position of calibrator PKS 0528+134 is correct. We further
made a hybrid map by performing several iterations of CLEAN and
self-calibration on the phase-referenced data with the phase-reference map as
an input model for the first phase self-calibration. Compared with the hybrid
map from the limited visibility data directly obtained from fringe fitting 3C
138 data, this map has a similar dynamic range, but a higher angular
resolution. Therefore, phase-reference technique is not only a means of phase
connection, but also a means of increasing phase coherence time allowing
self-calibration technique to be applied to much weaker sources.Comment: 9 pages plus 2 figures, accepted by PASJ (Vol.58 No.6
Effect of CYP2C9*3 gene polymorphism on lipid-lowering efficacy of fluvastatin in a Chinese hyperlipidemic population
Purpose: To investigate the frequency of gene CYP2C9*3 in Chinese populations, and to analyze the impact of CYP2C9*3 genetic polymorphism on the cholesterol-lowering effect of fluvastatin in a Chinese hyperlipidemic population.Methods: CYP2C9 genotype was determined by polymerase chain reaction - restriction fragment length polymorphism (PCR - RFLP) in 270 unrelated hyperlipidemic patients who were treated with 80mg fluvastatin monotherapy daily for 4 weeks and 250 healthy controls. Clinical data were collected prior to treatment with fluvastatin and 4 weeks after.Results: In 270 hyperlipidemic patients, the frequency of CYP2C9*3 was 3.70 % which is significantly higher than in 250 healthy controls (2.60 %) (p < 0.01). After oral intake of fluvastatin 80 mg daily for 4 weeks, CYP2C9*1/*3 genotype was associated with a decrease in LDL-C levels (by 33.9 % in CYP2C9*1/*3 versus 24.5 % for CYP2C9*1/*1, p < 0.05) and with reduction of TC (by 36.4 % in CYP2C9*1/*3 versus 19.4 % in CYP2C9*1/*1, p < 0.05).Conclusion: The frequency of CYP2C9*3 is 3.17 % in Chinese populations, and those who carry CYP2C9*3 mutation have a high risk of hyperlipidemia. CYP2C9*3 seems to increase the lipid-lowering effects of fluvastatin.Keywords: Hyperlipidemia, Gene, CYP2C9, Polymorphism, Polymerase chain reaction, Restriction fragment length polymorphism, Fluvastati
Linearly and Circularly Polarized Emission in Sagittarius A*
We perform general relativistic ray-tracing calculations of the transfer of
polarized synchrotron radiation through the relativistic accretion flow in
Sagittarius (Sgr) A*. Based on a two-temperature magneto-rotational-instability
(MRI) induced accretion mode, the birefringence effects are treated
self-consistently. By fitting the spectrum and polarization of Sgr A* from
millimeter to near-infrared bands, we are able to not only constrain the basic
parameters related to the MRI and the electron heating rate, but also limit the
orientation of the accretion torus. These constraints lead to unique
polarimetric images, which may be compared with future millimeter and
sub-millimeter VLBI observations. In combination with general relativistic MHD
simulations, the model has the potential to test the MRI with observations of
Sgr A*.Comment: 12 pages, 2 figures, ApJL accepte
N-(2-Hydroxy-5-nitrophenyl)methanesulfonamide ethanol monosolvate
In the title compound, C7H8N2O5S·C2H6O, the dihedral angle between the aromatic ring and the nitro group is 8.78 (9)° and the S atom is displaced by 0.226 (3) Å from the plane of the aromatic ring. In the crystal, the ethanol molecule is involved in hydrogen bonding to two separate sulfonamide molecules, as a donor in an O—H⋯O interaction and as an acceptor in an N—H⋯O interaction. Weak C—H⋯O hydrogen bonding is also present
Efficient quantum direct communication with authentication
Two protocols of quantum direct communication with authentication [Phys. Rev.
A 73, 042305(2006)] were recently indicated to be insecure against the
authenticator Trent's attacks [Phys. Rev. A 75, 026301(2007)]. We present two
efficient protocols by using four Pauli operations, which are secure against
inner Trent's attacks as well as outer Eve's attacks. Finally, we generalize
them to multiparty quantum direction communication.Comment: 4 pages, 4 table
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