As in other OECD countries, public pension insolvency is now one of the most serious problems that an aging society poses for the Japanese economy. The proportion of people aged 65 and above – 17.4 percent in 2000, which is close to the OECD average is expected to grow faster than in any other advanced country. The latest official population projections, published in January 2002, expect the share of elderly to rise to 28.7 percent in 2025 and 35.7 percent in 2050. These projections assume that the fertility rate will remain low at 1.39 by 2050, expecting no substantial recovery from 1.33 in 2001.
Rapid population aging is a big challenge to the sustainability of the social security system, which relies heavily on future generations. Under strong demographic pressures, the government announced a new pension reform plan in 1999 and has implemented it since April in 2000. Since Japan’s public pension program is basically a pay-as-you-go system, the government must reduce benefits and/or increase contributions in order to keep the programs financially sustainable. To finance pension benefits promised in the previous 1994 Reform, the contribution rate must eventually increase to 34.5 percent, which seems unacceptable. The 2000 Reform thus incorporates measures to hold down the burden on future generations by making eligibility conditions and benefit schemes less generous than previously scheduled.
The efficient market hypothesis (EMH) has been tested by different types of research. Its weak, and more clever form, postulates that the past trading prices and information of a stock (equity, commodity, derivative...) is entirely reflected on its value, meaning that historical trading data have no potential for predicting the behavior of future stock’s prices. Following this rule, we have as a direct consequence that no logical rules of trading based on historical data should have a positive excess return, that is economically or statistically significant, over some chosen benchmark portfolio. Of course this holds in theory. What is interesting to us is to verify if there is a margin between the practitioner’s and academic point of view, allowing portfolio managers to make profit in a systematic way.
This thesis addresses the problem of inter-particle collisions in a viscous liquid. Experimental measurements were made on normal and oblique collisions between identical and dissimilar pairs of solid spheres. The experimental evidence supports the hypothesis that the normal and the tangential component of motions are decoupled during a rapid collision.
