Exponential Growth of Distance between Nearby Rays due to Multiple Gravitational Scatterings

We give an estimate of the relative error in the angular measurement of observations for high redshift objects induced by gravitational scatterings (lensing). Gunn (1967) concluded that the gravitational scatterings by galaxies induce the relative error of a few percent in the observations for objects at $z=1$. This estimate has been considered as a fundamental limitation of accuracy of the angular measurements in the observational cosmology. In multiple graviational scatterings, bending angle of single ray grows through the random work process. Gunn (1967) assumed that the difference of nearby rays also grows through the random walk process. However, distance between nearby photons grows exponentially because the two rays suffer coherent scatterings by the same scattering object. This exponential growth continues as long as the scattering is coherent. In the case of scattering by individual galaxies, the exponential growth continues until the angular distance reaches an arcminute or so. The relative error of the angular measurements under an arcminute due to the exponential growth is $\sim 30\%$ at $z=1$ and exceeds $100\%$ at $z=3$, in the case that the density parameter of galaxies is 0.2. The effects of clusters of galaxies or superclusters are more difficult to estimate accurately, but might be significant. In the case of supercluster the angular measurements up to a few degrees could be affected.Comment: compressed uuencoded postscript, 8 pages including 5 figures, APJL accepte

Mass-Loss Timescale of Star Clusters in an External Tidal Field. II. Effect of Mass Profile of Parent Galaxy

We investigate the long-term dynamical evolution of star clusters in a steady tidal field produced by its parent galaxy. In this paper, we focus on the influence of mass profile of the parent galaxy. The previous studies were done with the simplification where the parent galaxy was expressed by point mass. We express different mass profiles of the parent galaxy by the tidal fields in which the ratios of the epicyclic frequency to the angular velocity are different. We compare the mass-loss timescale of star clusters whose tidal radii are identical but in parent galaxies with different mass profile, by means of orbits calculations in fixed cluster potential and N-body simulations. In this situation, a cluster rotates around the parent galaxy more rapidly as the parent galaxy has shallower mass profile. We found that the mass-loss timescale increase 20% and 50% for the cases that the mass density profile of the parent galaxies are proportional to R^-2 and R^-1.5 where R is the distance from the galaxy center, compared to the point-mass case, in moderately strong tidal field. Counterintuitively, a cluster which rotates around the parent galaxy more rapidly has a longer lifetime. The increase of lifetime is due to the fact that the fraction occupied by regular-like orbit increases in shallower profile. Finally, we derive an evaluation formula for the mass-loss timescale of clusters. Our formula can explain a property of the population of the observed galactic globular clusters that their half-mass radii become smaller as their distances from the galactic center become smaller.Comment: Submitted to PAS

Globalization and Economic Inequality in the Short and Long Run: The Case of South Korea 1975-1995

We have analyzed the determinants of the Gini coefficient for income and expenditure. In both cases, we do not find support for the Kuznets inverted-U hypothesis. From economic globalization viewpoint, the opening of goods markets reduces income inequality both in the short run (the Gini coefficient for income) and in the long run (the Gini coefficient for expenditure). On the other hand, the opening of capital markets increases income inequality both in the short and long run, but the latter is not statistically significant. These results suggest that the effect of economic globalization has two routes and two different speeds to affect income inequality.Globalization, Economic inequality, Gini coefficient, South Korea

Rational Consumers

The life cycle/permanent income hypothesis (LCPIH) makes two postulates: people behave with rational expectations, and people do not have self-control problems. If either or both of these postulates do not apply, we cannot obtain a testable implication of the LCPIH. We use Japanese panel data that include responses to self-reported and retrospective questions to elicit individual characteristics such as forward-looking behavior, experience of self-control problems, and use of commitment devices to overcome self-control problems. First, we test the rational expectations hypothesis and find that it holds for the whole sample. We then test the LCPIH implication and find that consumption does not change in response to expected income changes, which we restrict to fit the assumptions of the LCPIH. This result indicates that the LCPIH is a convincing model to account for the behavior of rational consumers who have rational expectations and no self-control problems. Our results also imply that responses to self-reported and retrospective questions are not meaningless when eliciting information on household characteristics.Life cycle/permanent income hypothesis; Excess sensitivity; Rational expectation; Self-control problems; sophisticated and naive.

Valuing Medical Schools in Japan: National versus Private Universities

Medical school usually has the highest tuition fees among the university departments. The reason why students pay such expensive fees is that they estimate that their earnings will greatly increase after graduation. We construct a model about student behavior on entering college and estimate the value-added of medical schools using college data from Japan. Our results show that a school with a long tradition of providing high quality education is evaluated as rendering high value-added to students. Those empirical results enable us to simulate the effects of the privatization of a public university. This simulation indicates that there is no difference between public and private schools when the tuition fees of the public university become as high as those of the private university.Value-added of University, Medical school tuition fee, Public and private schools, Privatization

The Chinese Economy and Income Inequality among East Asian Countries

Using the Atkinson inequality measure of income distribution, we analyze the impact of China as a single country and examine the effect of its domestic income inequality on total income inequality among East Asian countries. First, we find that China's domestic income inequality exacerbated income inequality among East Asian countries from the 1980s, and this effect became even more pronounced from 1990. Second, the growth of China's per capita GDP had an equalizing effect on income distribution in a framework of ASEAN + China, but this effect was reversed around 1997. However, relative to higher income countries such as Japan and South Korea, China's per capita GDP remains low, and although China has contributed to income inequality in the area, it has recently had a more equalizing effect.East Asia, China, income inequality, free trade agreement, harmonious society

Job Security Laws and Structural Change in the Japanese Labor Market

There are a number of indications that Japanese job security laws have been relaxed since the end of the 1990s. The purpose of this paper is to establish causality between job security laws and firing costs in the Japanese labor market. The analysis first investigates when and how firing costs changed, and then compares the timing of these changes in firing costs with those of job security laws. The results indicate that gradual changes in firing costs began in about 1992, lagging one or two years behind the bursting of the bubble economy, while job security laws started to change towards the end of the 1990s.Adjustment costs for labor; Gradual switching model; Job security laws

The End of Import-Led Growth? North Korean Evidence

In this paper, we investigate causal relationships among exports, imports, and economic growth in North Korea by using time series data for the period between 1964 and 2004. The empirical results show that there was Granger causality from imports to GNP in the first half of the period. However, there was a causal relationship from GNP to imports in the second half of the period. This implies that economic growth stimulates imports in North Korea. The North Korean economy escaped its import-led growth situation, which some socialist economies had experienced.North Korea, import-led growth, export-led growth, causality test.