155 research outputs found
Squeezing at 946nm with periodically-poled KTiOPO_4
We report generation of squeezed vacuum in sideband modes of continuous-wave
light at 946 nm using a periodically poled KTiOPO_4 crystal in an optical
parametric oscillator. At the pump power of 250 mW, we observe the squeezing
level of -5.6+/-0.1 dB and the anti-squeezing level of +12.7+/-0.1 dB. The pump
power dependence of the observed squeezing/anti-squeezing levels agrees with
the theoretically calculated values when the phase fluctuation of locking is
taken into account.Comment: 3 pages, 3 figures, submitted to Optics Letter
Discovery of Enhanced Radiative Recombination Continua of He-like Iron and Calcium from IC 443 and Its Implications
We present deep observations of the Galactic supernova remnant IC 443 with
the {\it Suzaku X-ray satellite}. We find prominent K-shell lines from iron and
nickel, together with a triangle residual at 8--10~keV, which corresponds to
the energy of the radiative recombination continuum (RRC) of He-like iron. In
addition, the wavy residuals have been seen at 5.1 and 5.5~keV. We
confirm that the residuals show the first enhanced RRCs of He- and H-like
calcium found in supernova remnants. These facts provide robust evidence for
the recombining plasma. We reproduce the plasma in the 3.7--10~keV band using a
recombining plasma model at the electron temperature 0.65~keV. The
recombination parameter ( is electron density and
is elapsed time after formation of a recombining plasma) and abundances of iron
and nickel are strongly correlated, and hence the errors are large. On the
other hand, the ratio of nickel to iron relative to the solar abundances is
well constrained to 11 (1). A possibility is that the large
abundance ratio is a result of an asymmetric explosion of the progenitor star.Comment: 4 pages, 5 figures, published in Ap
X-Ray Spectrum of a Peculiar Supernova Remnant G359.1-0.5
We present the Suzaku results of a supernova remnant (SNR), G359.1-0.5 in the
direction of the Galactic center region. From the SNR, we find prominent
K-shell lines of highly ionized Si and S ions, together with unusual structures
at 2.5-3.0 and 3.1-3.6 keV. No canonical SNR plasma model, in either ionization
equilibrium or under-ionization, can explain the structures. The energies and
shapes of the structures are similar to those of the radiative transitions of
free electrons to the K-shell of He-like Si and S ions (radiative recombination
continuum: RRC). The presence of the strong RRC structures indicates that the
plasma is in over-ionization. In fact, the observed spectrum is well fitted
with an over-ionized plasma model. The best-fit electron temperature of 0.29
keV is far smaller than the ionization temperature of 0.77 keV, which means
that G359.1-0.5 is in extreme condition of over-ionization. We report some
cautions on the physical parameters, and comment possible origins for the
over-ionized plasma.Comment: 7 pages, 5 figures, accepted for publication in PAS
Quantum error correction beyond qubits
Quantum computation and communication rely on the ability to manipulate
quantum states robustly and with high fidelity. Thus, some form of error
correction is needed to protect fragile quantum superposition states from
corruption by so-called decoherence noise. Indeed, the discovery of quantum
error correction (QEC) turned the field of quantum information from an academic
curiosity into a developing technology. Here we present a continuous-variable
experimental implementation of a QEC code, based upon entanglement among 9
optical beams. In principle, this 9-wavepacket adaptation of Shor's original
9-qubit scheme allows for full quantum error correction against an arbitrary
single-beam (single-party) error.Comment: realization of a Gaussian error correction protocol suitable for
non-Gaussian error correctio
Recombining Plasma and Hard X-ray Filament in the Mixed-Morphology Supernova Remnant W44
We report new features of the typical mixed-morphology (MM) supernova remnant
(SNR) W44. In the X-ray spectra obtained with Suzaku, radiative recombination
continua (RRCs) of highly ionized atoms are detected for the first time. The
spectra are well reproduced by a thermal plasma in a recombining phase. The
best-fit parameters suggest that the electron temperature of the shock-heated
matters cooled down rapidly from ,keV to ,keV, possibly due to
adiabatic expansion (rarefaction) occurred years ago. We also
discover hard X-ray emission which shows an arc-like structure
spatially-correlated with a radio continuum filament. The surface brightness
distribution shows a clear anti-correlation with CO (J=2-1) emission
from a molecular cloud observed with NANTEN2. While the hard X-ray is most
likely due to a synchrotron enhancement in the vicinity of the cloud, no
current model can quantitatively predict the observed flux.Comment: 10 pages, 5 figures, accepted for publication in PAS
ラムゼイ・ハント症候群症例の前庭蝸牛神経MRI造影効果と前庭蝸牛機能障害との関係
Objective: The correlation between enhancement of the vestibulocochlear nerves on gadolinium-enhanced magnetic resonance imaging (MRI) and vestibulocochlear functional deficits was examined in patients with Ramsay Hunt syndrome (RHS).
Methods: Nineteen patients with RHS who showed herpes zoster oticus, peripheral facial palsy, and vertigo were enrolled. Canal paresis (CP) in the caloric test, abnormal response to ocular and cervical vestibular myogenic potentials (oVEMP and cVEMP), and refractory sensorineural hearing loss were evaluated. MRI images perpendicular to the internal auditory canal were reconstructed to identify the superior (SVN) and inferior vestibular nerves (IVN) and the cochlear nerve (CV). The signal intensity increase (SIinc) of the four-nerve enhancement was calculated as an index.
Results: Among RHS patients, 79%, 53%, 17% and 26% showed CP in the caloric test, abnormal responses to oVEMP and cVEMP, and refractory sensorineural hearing loss, respectively. SIinc rates of the SVN were significantly increased in RHS patients with CP in the caloric test, and with abnormal responses to oVEMP and cVEMP. SIinc rates of the SVN tended to increase in RHS patients with refractory sensorineural hearing loss ( p = 0.052). SIinc rates of the IVN were significantly increased in RHS patients with abnormal responses to oVEMP and cVEMP, and refractory sensorineural hearing loss, but not in those with CP in the caloric test. SIinc rates of the CN were significantly increased in RHS patients with CP in the caloric test, abnormal response to oVEMP and refractory sensorineural hearing loss, but not in those with abnormal response to cVEMP.
Conclusion: In patients with RHS, the origin of vertigo may be superior vestibular neuritis, which is affected by reactive varicella-zoster virus from the geniculate ganglion of the facial nerve through the faciovestibular anastomosis. The results also suggested that in some RHS patients, inferior vestibular neuritis contributes to the development of vertigo and that the origin of refractory sensorineural hearing loss is cochlear neuritis
Suzaku observation of the metallicity distribution in the intracluster medium of the Fornax cluster
The metallicity distribution in the Fornax cluster was studied with the XIS
instrument onboard the Suzaku satellite. K-shell lines of O and Mg were
resolved clearly, and the abundances of O, Mg, Si, S and Fe were measured with
good accuracy. The region within a 4' radius of NGC 1399 shows approximately
solar abundances of Fe, Si and S, while the O/Fe and Mg/Fe abundance ratios are
about 0.4--0.5 and 0.7 in solar units. In the outer region spanning radii
between 6' and 23', the Fe and Si abundances drop to 0.4--0.5 solar and show no
significant gradient within this region. The abundance ratios, O/Fe and Mg/Fe,
are consistent with those in the central region. We also measured the Fe
abundance around NGC 1404 to be approximately solar, and the O, Ne and Mg
abundances to be 0.5--0.7 times the Fe level. The significant relative
enhancement of Fe within 130 kpc of NGC 1399 and in NGC 1404 indicates an
origin in SN Ia, in contrast to the species O, Ne, and Mg which reflect the
stellar metallicity. The mass-to-light ratios for O and Fe within 130 kpc of
NGC 1399 are over an order of magnitude lower than those in rich clusters,
reflecting the metal enrichment history of this poor cluster.Comment: 13 pages, accepted to PAS
Synthesis of (difluoromethyl)naphthalenes using the ring construction strategy: C–C bond formation on the central carbon of 1,1-difluoroallenes via Pd-catalyzed insertion
The insertion of 1,1-difluoroallenes was carried out to form a C–C bond exclusively on their central carbon. o-Bromophenyl-bearing 1,1-difluoroallenes underwent intramolecular insertion in the presence of a palladium catalyst. Regioselective C–C bond formation occurred to form a six-membered carbocycle, leading to pharmaceutically and agrochemically promising difluoromethylated naphthalenes
Golimumab in combination with methotrexate in Japanese patients with active rheumatoid arthritis: results of the GO-FORTH study
Objective: To assess the efficacy and safety of golimumab + methotrexate (MTX) in Japanese patients with active rheumatoid arthritis (RA). Methods: 269 Japanese patients with active RA despite treatment with MTX were randomised (1:1:1) to placebo + MTX (Group 1), golimumab 50 mg + MTX (Group 2) or golimumab 100 mg + MTX (Group 3). Subcutaneous golimumab/placebo was injected every 4 weeks; stable doses of oral MTX (6-8 mg/week) were continued. Patients were allowed to enter early escape (Group 1 added golimumab 50 mg, Group 2 increased golimumab to 100 mg, Group 3 continued golimumab 100 mg) based on swollen/tender joint counts at week 14. The primary study endpoint was achievement of at least 20% improvement in the American College of Rheumatology (ACR20) response criteria at week 14. To control for multiplicity of testing, treatment group comparisons were first made between combined Groups 2 and 3 versus Group 1, followed by comparisons of Group 2 and Group 3 versus Group 1. Results: The proportion of patients with an ACR20 response at week 14 was significantly higher in combined Groups 2 and 3 (73.4%, 127/173) and in each of Group 2 (72.1%, 62/86) and Group 3 (74.7%, 65/87) compared with Group 1 (27.3%, 24/88; p<0.0001 for all comparisons). Golimumab + MTX also elicited a significantly better response than placebo + MTX in other efficacy parameters, including disease activity score (DAS28) response/remission and radiographic assessments. During the 16-week fixed treatment regimen study period, 72.7%, 75.6% and 78.2% of patients had adverse events and 1.1%, 1.2% and 2.3% had serious adverse events in Groups 1, 2 and 3, respectively. Conclusion: In Japanese patients with active RA despite MTX therapy, golimumab + MTX was significantly more effective than MTX monotherapy in reducing RA signs/symptoms and limiting radiographic progression with no unexpected safety concerns
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