Monte-Carlo Modeling of Non-Gravitational Heating Processes in Galaxy Clusters

We consider non-gravitational heating effects on galaxy clusters on the basis of the Monte-Carlo modeling of merging trees of dark matter halos combined with the thermal evolution of gas inside each halo. Under the assumption of hydrostatic equilibrium and the isothermal gas profiles, our model takes account of the metallicity evolution, metallicity-dependent cooling of gas, supernova energy feedback, and heating due to jets of radio galaxies in a consistent manner. The observed properties of galaxy clusters can be explained in models with higher non-gravitational heating efficiency than that in the conventional model. Possibilities include jet heating by the Fanaroff-Riley Type II radio galaxies, and the enhanced star formation efficiency and/or supernova energy feedback, especially at high redshifts.Comment: 29 pages, 12 figures. To appear in PASJ, February 25, 200

Reliability of merger tree realizations of dark halos in the Monte-Carlo modeling of galaxy formation

We examine the reliability of the merger trees generated for the Monte-Carlo modeling of galaxy formation. In particular we focus on the cold gas fraction predicted from the merger trees with different assumptions on the progenitor distribution function, the timestep, and the mass resolution. We show that the cold gas fraction is sensitive to the accuracy of the merger trees at small-mass scales of progenitors at high redshifts. One can reproduce the Press-Schechter prediction to a reasonable degree by adopting a fairly large number of redshift bins, N_{step} ~ 1000 in generating merger trees, which is a factor of ten larger than the canonical value used in previous literature.Comment: 9 pages, 10 figures. To appear in PASJ, October 25, 200

The Square of Opposition with “most” and “many”

Our concern is with constructing a traditional square of opposition into which “most” and “many” are integrated. Our basic position is in favor of traditional formal logic that originated with Aristotle, but the present discussion have taken liberties with recent developments of formal semantics to such an extent that they make contribution to more understanding of what the square of opposition looks like. The concept of directionality of monotonicity and especially our tests contribute to our conclusion. Still our discussion finds crucial insight in Keynes, one of formal logicians of a century ago. We propose as a conclusion a traditional square of opposition in which a near universal and near particular are neatly incorporated into a traditional proto-type square in such a way that they are entirely wrapped up.departmental bulletin pape

Learner-Friendly Kanji Learning System with Radical Analysis

This paper presents a novel friendly Kanji learning system using Radical Analysis to enable foreign people and elementary school students to learn Kanji by an interesting and efficient way. This way is for characters to analyze for each radical, to divide into some parts, and to correct strokes for each divided part. Here, the Radical Analysis Database (RAD) is used for dividing characters. RAD is a database to analyze characters for each radical and divide into some parts. On the other hand, characters are corrected by using a threshold. The threshold is a judgment value in the correction and learners can set it freely by handling threshold bars put on the interface. Then, the novel system is improved so that learners can set thresholds for each divided part. Since each bar corresponds to each part, the system judges whether each part is corrected or not according to set thresholds. Hence, since learners can freely determine radicals or parts in which they want to be instructed intensively, they can practice only their radicals not good or part of the character and easily master difficult characters, too. In addition, an animation helps learners understand the order of strokes virtually. Since each stroke used in this animation is displayed with different colors, learners can also understand virtually where the same strokes are from and to at once.DOI: http://dx.doi.org/10.11591/ijere.v1i1.47

Which Component of Solar Magnetic Field Drives the Evolution of Interplanetary Magnetic Field over Solar Cycle?

The solar magnetic structure changes over the solar cycle. It has a dipole structure during solar minimum, where the open flux extends mainly from the polar regions into the interplanetary space. During maximum, a complex structure is formed with low-latitude active regions and weakened polar fields, resulting in spread open field regions. However, the components of the solar magnetic field that is responsible for long-term variations in the interplanetary magnetic field (IMF) are not clear, and the IMF strength estimated based on the solar magnetic field is known to be underestimated by a factor of 3 to 4 against the actual in-situ observations (the open flux problem). To this end, we decomposed the coronal magnetic field into the components of the spherical harmonic function of degree and order $(\ell, m)$ using the potential field source surface model with synoptic maps from SDO/HMI for 2010 to 2021. As a result, we found that the IMF rapidly increased in December 2014 (seven months after the solar maximum), which coincided with the increase in the equatorial dipole, $(\ell, m)=(1, \pm1)$, corresponding to the diffusion of active regions toward the poles and in the longitudinal direction. The IMF gradually decreased until December 2019 (solar minimum) and its variation corresponded to that of the non-dipole component $\ell\geq2$. Our results suggest that the understanding of the open flux problem may be improved by focusing on the equatorial dipole and the non-dipole component and that the influence of the polar magnetic field is less significant.Comment: 19 pages, 9 figures, accepted for publication in Ap

Tau phosphorylation at Alzheimer\u27s disease-related Ser356 contributes to tau stabilization when PAR-1/MARK activity is elevated.

Abnormal phosphorylation of the microtubule-associated protein tau is observed in many neurodegenerative diseases, including Alzheimer\u27s disease (AD). AD-related phosphorylation of two tau residues, Ser262 and Ser356, by PAR-1/MARK stabilizes tau in the initial phase of mismetabolism, leading to subsequent phosphorylation events, accumulation, and toxicity. However, the relative contribution of phosphorylation at each of these sites to tau stabilization has not yet been elucidated. In a Drosophila model of human tau toxicity, we found that tau was phosphorylated at Ser262, but not at Ser356, and that blocking Ser262 phosphorylation decreased total tau levels. By contrast, when PAR-1 was co-overexpressed with tau, tau was hyperphosphorylated at both Ser262 and Ser356. Under these conditions, the protein levels of tau were significantly elevated, and prevention of tau phosphorylation at both residues was necessary to completely suppress this elevation. These results suggest that tau phosphorylation at Ser262 plays the predominant role in tau stabilization when PAR-1/MARK activity is normal, whereas Ser356 phosphorylation begins to contribute to this process when PAR-1/MARK activity is abnormally elevated, as in diseased brains

Systematic bias in the estimate of cluster mass and the fluctuation amplitude from cluster abundance statistics

We revisit the estimate of the mass fluctuation amplitude, sigma_8, from the observational X-ray cluster abundance. In particular, we examine the effect of the systematic difference between the cluster virial mass estimated from the X-ray spectroscopy, M_{vir, spec}, and the true virial mass of the corresponding halo, M_{vir}. Mazzotta et al. (2004) recently pointed out the possibility that alpha_M = M_{vir, spec}/M_{vir} is systematically lower than unity. We perform the statistical analysis combining the latest X-ray cluster sample and the improved theoretical models and find that sigma_8 \sim 0.76 +/- 0.01 + 0.50 (1-alpha_M) for 0.5 \le alpha_M \le 1, where the quoted errors are statistical only. Thus if alpha_M \sim 0.7, the value of sigma_8 from cluster abundance alone is now in better agreement with other cosmological data including the cosmic microwave background, the galaxy power spectrum and the weak lensing data. The current study also illustrates the importance of possible systematic effects in mapping real clusters to underlying dark halos which changes the interpretation of cluster abundance statistics.Comment: 13 pages, 4 figures. To appear in PASJ, April 25, 200