Japan's Civil Registration Systems Before and After the Meiji Restoration

This essay traces the evolution of Japan's systems of household and land registration from Tokugawa times to the period of early Meiji reforms in the 1870s and 80s. The paper pays due attention to the distinction between an early modern system designed by state authority and local forms of　registration practice. Thus, in the section on the Tokugawa period, one such local practice of having people 'disowned' and its consequence,　registerlessness, will be examined. The section on the Meiji reforms turns to the issue of continuity and discontinuity, while the next section discusses if any progress in terms of civil identity registration was made by these Meiji reforms. In order to illustrate the actual changes that took place at the local level, the essay begins with an eighteenth-century story about a peasant woman and her disputes with the village officialdom and ends with a case of family dispute that another village woman brought before court some 120 years later.

Relativistic mean-field model with density-dependent meson-nucleon couplings

Within the relativistic mean-field approach, we extend the Miyazaki model, where the NN$\sigma$ and NN$\omega$ interactions are modified to suppress the couplings between positive- and negative-energy states of a nucleon in matter. Assuming appropriate density-dependence of the meson-nucleon couplings, we study nuclear matter and finite nuclei. The model can reproduce the observed properties of $^{16}$O and $^{40}$Ca well. We also examine if the model is natural.Comment: 6 pages, 3 figure

Nonlinear power spectrum in the presence of massive neutrinos: perturbation theory approach, galaxy bias and parameter forecasts

Future or ongoing galaxy redshift surveys can put stringent constraints on neutrinos masses via the high-precision measurements of galaxy power spectrum, when combined with cosmic microwave background (CMB) information. In this paper we develop a method to model galaxy power spectrum in the weakly nonlinear regime for a mixed dark matter (CDM plus finite-mass neutrinos) model, based on perturbation theory (PT) whose validity is well tested by simulations for a CDM model. In doing this we carefully study various aspects of the nonlinear clustering and then arrive at a useful approximation allowing for a quick computation of the nonlinear power spectrum as in the CDM case. The nonlinear galaxy bias is also included in a self-consistent manner within the PT framework. Thus the use of our PT model can give a more robust understanding of the measured galaxy power spectrum as well as allow for higher sensitivity to neutrino masses due to the gain of Fourier modes beyond the linear regime. Based on the Fisher matrix formalism, we find that BOSS or Stage-III type survey, when combined with Planck CMB information, gives a precision of total neutrino mass constraint, sigma(m_nu,tot) 0.1eV, while Stage-IV type survey may achieve sigma(m_nu,tot) 0.05eV, i.e. more than a 1-sigma detection of neutrino masses. We also discuss possible systematic errors on dark energy parameters caused by the neutrino mass uncertainty. The significant correlation between neutrino mass and dark energy parameters is found, if the information on power spectrum amplitude is included. More importantly, for Stage-IV type survey, a best-fit dark energy model may be biased and falsely away from the underlying true model by more than the 1-sigma statistical errors, if neutrino mass is ignored in the model fitting.Comment: 33 pages, 11 figure

The effect of varying sound velocity on primordial curvature perturbations

We study the effects of sudden change in the sound velocity on primordial curvature perturbation spectrum in inflationary cosmology, assuming that the background evolution satisfies the slow-roll condition throughout. It is found that the power spectrum acquires oscillating features which are determined by the ratio of the sound speed before and after the transition and the wavenumeber which crosses the sound horizon at the transition, and their analytic expression is given. In some values of those parameters, the oscillating primordial power spectrum can better fit the observed Cosmic Microwave Background temperature anisotropy power spectrum than the simple power-law power spectrum, although introduction of such a new degree of freedom is not justified in the context of Akaike's Information Criterion.Comment: 12 pages, 3 figures; references added; appendix modifie

Neutrino Mass Constraint from the Sloan Digital Sky Survey Power Spectrum of Luminous Red Galaxies and Perturbation Theory

We compare the model power spectrum, computed based on perturbation theory, with the power spectrum of luminous red galaxies (LRG) measured from the Sloan Digital Sky Survey Data Release 7 catalog, assuming a flat, cold dark matter-dominated cosmology. The model includes the effects of massive neutrinos, nonlinear matter clustering and nonlinear, scale-dependent galaxy bias in a self-consistent manner. We first test the accuracy of the perturbation theory model by comparing the model predictions with the halo power spectrum in real- and redshift-space, measured from 70 simulation realizations for a cold dark matter model without massive neutrinos. We show that the perturbation theory model with bias parameters being properly adjusted can fairly well reproduce the simulation results. As a result, the best-fit parameters obtained from the hypothetical parameter fitting recover, within statistical uncertainties, the input cosmological parameters in simulations, including an upper bound on neutrino mass, if the power spectrum information up to k ≃ 0.15 hMpc-1 is used. However, for the redshift-space power spectrum, the best-fit cosmological parameters show a sizable bias from the input values if using the information up to k ≃ 0.2 hMpc-1, probably due to nonlinear redshift distortion effect. Given these tests, we decided, as a conservative choice, to use the LRG power spectrum up to k=0.1 hMpc-1 in order to minimize possible unknown nonlinearity effects. In combination with the recent results from Wilkinson Microwave Background Anisotropy Probe (WMAP), we derive a robust upper bound on the sum of neutrino masses, given as ∑ mν ≤ 0. 81eV (95% C.L.), marginalized over other parameters including nonlinear bias parameters and dark energy equation of state parameter. The upper bound is only slightly improved to ∑ mν ≤ 0.80eV if including the LRG spectrum up to k = 0.2 hMpc-1, due to severe parameter degeneracies, although the constraint may be biased as discussed above. The neutrino mass limit is improved by a factor of 1.85 compared to the limit from the WMAP5 alone, ∑ mν ≤ 1.5eV