Simulation Analysis of the Revision of the Survivors' Pension System (Japanese)

In this paper we discuss the impact of potential proposed revisions to the survivors' pension system on the stability of pension finance and on intergenerational and intragenerational equitability. The three proposals we study are: (1) the proposal that the survivors' pension benefit be reduced to approximately 50% of the husband's benefit, as in Europe, (2) the proposal that the pension benefit received by a husband-wife household be revised to the income-averaging method in which the contributions of spouses are averaged over the duration of the marriage in calculating the amount of pension benefits of the spouses, and (3) the proposal, modelled on the Swedish method, that survivor benefits be separated from the Employees' Pension Insurance system, the funding based on general tax revenue, and employee pensions netted off by the amount of the survivors' benefits, based on the insurance principle. Our conclusions are as follows. First, so long as the current public pension system is built on the Basic Pension System which apportions benefits to every pensioner, it will not be possible to consider reducing the period of application of the macroeconomic slide system, as that would lead to the destruction of the National Pension System. In view of this, if these revision proposals were implemented it would be appropriate to alleviate the burden of Employees' Pension Insurance premiums. An incidental effect of this would be that the amount of the reserves of the public pension system, which are forecast to accumulate astronomically under the present finite balance system, could be reduced to some degree. This could be expected to have the effect of alleviating or avoiding the risk arising from fluctuations in investment returns. In addition, with regard to the internal rate of return (IRR) of employee pensions, we examine the impact of each of the revision proposals on different generations within and between types of household. The implementation of each of the proposals would give rise to the existence of vested pensioners who suffer declines in IRR, particularly in the model households for the middle-aged and elderly generations, though many households, in the young generation in particular, would benefit from a lower insurance premium burden. Combined with the fact that under the finite balance system it will primarily be the young generation that benefits from the run-down of the reserves left by the middle-aged and elderly generations, the generation gap can be expected to narrow somewhat. We also confirm that, as would be expected, the reduction and separation of the survivors' pension benefit generally reduces the gap between the model households and the other types of household.

Hidden Symmetry Protection and Topology in Surface Maxwell Waves

Since the latter half of the 20th century, the use of metal in optics has become a promising plasmonics field for controlling light at a deep subwavelength scale. Surface plasmon polaritons localized on metal surfaces are crucial in plasmonics. However, despite the long history of plasmonics, the underlying mechanism producing the surface waves is not fully understood. This study unveils the hidden symmetry protection that ensures the existence of degenerated electric zero modes. These zero modes are identified as physical origins of surface plasmon polaritons, and similar zero modes can be directly excited at a temporal boundary. In real space, the zero modes possess vector-field rotation related to surface impedance. Focusing on the surface impedance, we prove the bulk-edge correspondence, which guarantees the existence of surface plasmon polaritons even with nonuniformity. Lastly, we extract the underlying physics in the topological transition between metal and dielectric material using a minimal circuit model with duality. The transition is considered the crossover between electric and magnetic zero modes.Comment: 26 pages, 19 figures, minor correction

Impact of Greater Longevity on Pension Financing (Japanese)

Although greater longevity is coupled with a lower birthrate as one of the major causes of Japan's aging population, when it comes to factors influencing pension financing, longevity has not attracted as much attention as the birthrate. This paper quantitatively evaluates the impact of greater longevity on pension financing and examines the extent to which improvements can be expected in the sustainability of pension financing, by raising the eligibility age, using Population Projections for Japan: 2001-2050 with multiple assumptions for a longer life-span. Raising the eligibility age will improve pension financing quite considerably but this is an issue that needs to be debated in the future. At the same time, however, Japan should develop an infrastructure for social security systems and the labor market that will enable older workers to maintain their vigor as they work. This paper also conducts a simulation analysis of pension financing by concomitantly using the pension actuarial model and the life-cycle general equilibrium model so that the effects of changes in the population structure, through longer life-spans on the macro economy, can be taken into account. By using the pension actuarial model and the life-cycle general equilibrium model together, it will be possible to examine economic assumptions used in pension financing estimates, while consistently factoring in the impact of greater longevity on wage and interest rates from the standpoint of the life-cycle hypothesis. As estimates of pension financing cover extremely long periods of 100 years or so, it is necessary to pay greater attention to factors such as the aging population and life-cycle, which can cause dynamic fluctuations at the macro level. Pension estimates produced by the Ministry of Health, Labour and Welfare use fixed economic assumptions and regardless of which population assumptions are used, the research results in this paper indicate the possibility that in time, assumptions may lose their accuracy.

Wntシグナルを活性化する幹細胞増殖因子R-spondinの代替え低分子化合物の同定

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 田中 廣壽, 東京大学特任准教授 瀧本 英樹, 東京大学准教授 大庭 伸介, 東京大学講師 辛 正廣, 東京大学准教授 内田 寛治University of Tokyo(東京大学

Establishing Principles for a More Sustainable Pension System in Japan, and Identifying Challenges (Japanese)

This paper looks into the intermingling of the self insurance and public assistance principles in Japan's government-sponsored pension system that has been eroding public trust in the system. Using a newly developed pension funding model (the RIETI model), we analyze options for reforms quantitatively by clarifying the respective roles to be played by the financially fair insurance model and public assistance to poor retirees. In particular, we have simulated a pair of reform options: (1) fund the entire Basic Pension by the national treasury as a form of minimum guarantee to all the people in accordance with the assistance principle and Employees' Welfare Pension will be purified as a earning-related financially fair system on top of the Basic Pension, (2) reorganizing the National Pension and Employees' Welfare Pension systems into a new integrated, single-tier pension based on an earnings-related financially fair mechanism, with a supplementary pension for low-income pension recipients paid entirely from the national treasury on the basis of the assistance principle. In the first reform option, if the level of Employees' Welfare Pension contributions set out in the 2004 pension reform were maintained for second-tier contributions, a benefit multiplier of approximately 1.91 times the current rate could be achieved. If benefits were maintained at the levels set in the 2004 reform, the contribution rate for the second-tier pension could be reduced to about 11.93%. In these cases, an additional 7-point hike in the consumption tax would be required to fund Basic Pension benefits at the peak of old-age population. In the second reform option, the additional consumption tax would be relatively low, but the asset size of the earning-related pension system would greatly expand, creating a reserve fund twice as large as that under the current system. We have concluded that the capital market impact of introducing such a system needs to be taken into consideration. Furthermore, our simulations demonstrate that switching to such a system would significantly change the relationship between benefits and contributions. Therefore introduction of the new system would improve the return on contributions for some income groups and diminish it for others.

Comparison of glucose monitoring between Freestyle Libre Pro and iPro2 in patients with diabetes mellitus

Aims/Introduction: Flash and continuous glucose monitoring systems are becomingprevalent in clinical practice. We directly compared a flash glucose monitoring system(FreeStyle Libre Pro [FSL-Pro]) with a continuous glucose monitoring system (iPro2) inpatients with diabetes mellitus.Materials and Methods: Glucose concentrations were simultaneously measured usingthe FSL-Pro, iPro2 and self-monitoring blood glucose in 10 patients with diabetes mellitus,and agreement among them was assessed.Results: Parkes error grid analysis showed that the 92.9 and 7.1% of glucose valuesmeasured using the FSL-Pro fell into areas A and B, respectively, and that 96.3, 2.8 and0.9% of those determined using iPro2 fell into areas A, B and C, respectively. The medianabsolute relative differences compared with self-monitoring blood glucose were 8.1%(3.9–12.7%) and 5.0% (2.6–9.1%) for the FSL-Pro and iPro2, respectively. Analysis of 5,555paired values showed a close correlation between FSL-Pro and iPro2 glucose values(q = 0.96, P < 0.01). Notably, 65.3% of all glucose values were lower for the FSL-Pro thanthe iPro2. Median glucose values also decreased by 3.3% for the FSL-Pro compared withthe iPro2 (177.0 [133.0–228.0] vs 183.0 [145.0–230.0] mg/dL, P < 0.01). The difference inglucose values between the two systems was more pronounced in hypoglycemia. Themedian absolute relative difference between FSL-Pro and iPro2 during hypoglycemia wasmuch larger than that during euglycemia and hyperglycemia.Conclusions: Both the FSL-Pro and iPro2 systems are clinically acceptable, but glucosevalues tended to be lower when measured using the FSL-Pro than the iPro2. Agreementwas not close between these systems during hypoglycemia