101 research outputs found
Cosmic shear statistics in the Suprime-Cam 2.1 sq deg field: Constraints on Omega_m and sigma_8
We present measurements of the cosmic shear correlation in the shapes of
galaxies in the Suprime-Cam 2.1 deg^2 R_c-band imaging data. As an estimator of
the shear correlation originated from the gravitational lensing, we adopt the
aperture mass variance. We detect a non-zero E mode variance on scales between
2 and 40arcmin. We also detect a small but non-zero B mode variance on scales
larger than 5arcmin. We compare the measured E mode variance to the model
predictions in CDM cosmologies using maximum likelihood analysis. A
four-dimensional space is explored, which examines sigma_8, Omega_m, Gamma and
zs (a mean redshift of galaxies). We include three possible sources of error:
statistical noise, the cosmic variance estimated using numerical experiments,
and a residual systematic effect estimated from the B mode variance. We derive
joint constraints on two parameters by marginalizing over the two remaining
parameters. We obtain an upper limit of Gamma0.9 (68% confidence).
For a prior Gamma\in[0.1,0.4] and zs\in[0.6,1.4], we find
sigma_8=(0.50_{-0.16}^{+0.35})Omega_m^{-0.37} for flat cosmologies and
sigma_8=(0.51_{-0.16}^{+0.29})Omega_m^{-0.34}$ for open cosmologies (95%
confidence). If we take the currently popular LCDM model, we obtain a
one-dimensional confidence interval on sigma_8 for the 95.4% level,
0.62<\sigma_8<1.32 for zs\in[0.6,1.4]. Information on the redshift distribution
of galaxies is key to obtaining a correct cosmological constraint. An
independent constraint on Gamma from other observations is useful to tighten
the constraint.Comment: 12 pages, 12 figures, accepted for publication in Ap
Characteristics of plasma parameters and turbulence in the isotope-mixing and the non-mixing states in hydrogen–deuterium mixture plasmas in the large helical device
Characteristics of plasma parameters and turbulence in the isotope-mixing and the non-mixing states in hydrogen-deuterium mixture plasmas in the large helical device are discussed. The isotope mixing state is characterized by the uniform isotope ratio profile regardless of the location of the particle source of each species in the isotope mixture plasma. The isotope non-mixing state is identified by the non-uniform isotope ratio profile measured with bulk charge exchange spectroscopy when the beam fueling isotope species differs from the recycling isotope species. The effect of collisionality, ratio, sign of density gradient on transition between isotope mixing and non-mixing is discussed. The plasma parameters preferable for the non-mixing state are found to be lower collisionality, higher , and negative or zero density gradient (peaked or flat density profile). The time scale of transition from non-mixing to mixing is evaluated by the hydrogen and deuterium pellet injection near the plasma edge and is found to be less than 5 ms, which is much shorter than the particle confinement time. The strong correlation between isotope mixing and turbulence characteristics is observed. This strong correlation suggests the change in turbulence is a strong candidate for the mechanism causing the transition between uniform and non-uniform isotope density ratio profiles
Characterization of isotope effect on ion internal transport barrier and its parameter dependence in the Large Helical Device
In this paper, the background physics of the isotope effects in the ion internal transport barrier (ITB) are discussed in detail. An heuristic criterion for the ITB strength is defined based on the nonlinear dependence of the ion thermal diffusivity on the local ion temperature in the L-mode phase. Comparing deuterium plasmas and hydrogen plasmas, two isotope effects on the ion ITB are clarified: stronger ITBs formed in the deuterium plasmas and an ITB concomitant edge confinement degradation in the hydrogen plasmas. Principal component analysis reveals that the ion ITB becomes strong when a high input power normalized by the line averaged electron density is applied and electron density profile is peaked. A gyrokinetic simulation suggests that the ITB profile is determined by the ion temperature gradient driven turbulence, while the way the profile saturates in L-mode plasmas is unknown. In the electron density turbulence behavior, a branch transition is observed, where the increasing trend in turbulence amplitude against the ITB strength is flipped to a decreasing trend across the ITB formation. The radial electric field structure is measured by the charge exchange recombination spectroscopy system. It is found that the radial electric field shear plays a minor role in determining the ITB strength
Transition between Isotope-Mixing and Nonmixing States in Hydrogen-Deuterium Mixture Plasmas
The transition between isotope-mixing and nonmixing states in hydrogen-deuterium mixture plasmas is observed in the isotope (hydrogen and deuterium) mixture plasma in the Large Helical Device. In the nonmixing state, the isotope density ratio profile is nonuniform when the beam fueling isotope species differs from the recycling isotope species and the profile varies significantly depending on the ratio of the recycling isotope species, although the electron density profile shape is unchanged. The fast transition from nonmixing state to isotope-mixing state (nearly uniform profile of isotope ion density ratio) is observed associated with the change of electron density profile from peaked to hollow profile by the pellet injection near the plasma periphery. The transition from nonmixing to isotope-mixing state strongly correlates with the increase of turbulence measurements and the transition of turbulence state from TEM to ion temperature gradient is predicted by gyrokinetic simulation
Attenuation of Responsiveness to Interferon-α Treatment by Preceded Overactivation of Interferon-mediated Pathway in Patients Chronically Infected by Hepatitis C Virus
The Interferon (IFN) receptor-mediated signal transduction pathways involve the two novel DNA-binding factors, interferon regulatory factor-1 (IRF-1) and IRF-2. Both recognize the same DNA sequence, in which the expression ratio of IRF-1 to IRF-2 is relevant to induction of IFN-inducible genes, because IRF-1 acts as a transcriptional activator and IRF-2 as a counterpart. In the present study, 54 patients with chronic hepatitis C and the age-and sex-matched 7 subjects with fatty liver as a control were subjected to analysis of the expression ratio of IRF-1 to IRF-2 mRNA in the liver tissue obtained at the time of livert biopsy by reverse transcription-polymerase chain reaction in combination with a restriction fragment length polymorphism assay. The expression ratio of IRF-1 to IRF-2 mRNA in the liver tissue in patients chronically infected by hepatitis C virus (HCV) was significantly higher than that in control, although the values did not correlate with the serum levels of HCV-RNA. Of 54 patients, 28 received IFN treatment, resulting in complete response in 8 patients. With respect to responsiveness to IFN treatment, patients who had complete response had the relatively lower ratios of IRF-1 to IRF-2 mRNA in the liver tissue, compared with those who did not. These results indicate that the IFN-mediated pathway is spontaneously activated in patients with chronic hepatitis C, and that its preceded overactivation counteracts on the efficacy of IFN treatment in these patients
Searching for dark matter halos in the Suprime-Cam 2 sq deg field
We report the first result of weak gravitational lensing survey on a 2.1 sq
deg Rc-band image taken with a wide field camera (Suprime-Cam) on the prime
focus of 8.2 m Subaru Telescope. The weak lensing mass reconstruction is
applied to the data to search for dark matter halos of cluster scale; M >=
10^14 solar mass. The reconstructed convergence field is divided by 1-sigma
noise to obtain the signal-to-noise ratio map (S/N-map) of the detection. Local
maxima and minima are searched on the S/N-map and the probability distribution
function (PDF) of the peaks are created to compare with model predictions. We
found excess over noise PDF created from the randomized realization on both
positive and negative sides. Negative peaks imply the presence of voids in the
dark matter distribution and this is the first report of the detection.
Positive peaks, on the other hand, represent the dark matter halos and the
number count of the halos on the 2.1 sq deg image is 4.9 +- 2.3 for S/N > 5
where the Gaussian smoothing radius of the convergence map is 1'. The result is
consistent with the prediction assuming the Press-Schechter mass function and
the NFW halo profile under the cluster normalized CDM cosmology. Although the
present statistics is not enough due to the limited field of view, this work
demonstrates that dark matter halo count via weak lensing is a promising way to
test the paradigm of structure formation and cosmological model.Comment: 4 pages, 3 figures, Accepted for publication in ApJ
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