Macroeconomic Impacts of Aging in Japan on the Balance of Current Accounts

This paper investigates questions regarding the saving rates by age brackets and aggregate savings, and then conducts a simulation analysis of the current account, from the I-S balances of households, corporations and the government. Saving rates of the old (65 years old and above) with publicly available data are high because of a selection bias in household head, that excludes the old living with younger family members and being non-head of the household. The paper estimates the true saving rates by age brackets rather than of household head's age brackets with taking the non-head households' member into account. Estimated saving rates of the old are still positive (about 10% to 20% which are less than those of the young) even after adjusting for the bias. The impact of aging on the aggregate saving rates will not be large if the future old people continue to save as the current old people. We forecast the current account in several scenarios, using data of demographic changes, the estimated aggregate saving rates, and the estimated interest payments of government bonds. It is of our particular interest whether the current account will turn to be negative by the rapid demographic change. It is found that the IS balances would remain positive under a condition that the government bond issues would be constrained by fiscal sustainability.

Spanners under the Hausdorff and Fr\'echet Distances

We initiate the study of spanners under the Hausdorff and Fr\'echet distances. We show that any $t$-spanner of a planar point-set $S$ is a $\frac{\sqrt{t^2-1}}{2}$-Hausdorff-spanner and a $\min\{\frac{t}{2},\frac{\sqrt{t^2-t}}{\sqrt{2}}\}$-Fr\'echet spanner. We also prove that for any $t > 1$, there exist a set of points $S$ and an $\varepsilon_1$-Hausdorff-spanner of $S$ and an $\varepsilon_2$-Fr\'echet-spanner of $S$, where $\varepsilon_1$ and $\varepsilon_2$ are constants, such that neither of them is a $t$-spanner

Estimation of Saving Rates by Age Group in Japan using 2019 National Survey of Family Income, Consumption and Wealth

This paper estimates saving rates by age group in case of Japan using 2019 National Survey of Family Income, Consumption and Wealth（ NSFICW）. NSFICW is a large-scale survey with sample size of about 48,000 households for consumption expenditure and about 92,000 households for household revenue. We usually have saving rates of households, but those of individual are needed to investigate the effects of the decreasing birthrate and aging population on the average saving rates of macroeconomic level. This paper estimates the saving rates by age group. Some assumptions of transfers of income within a household are set. The results show the appropriate patterns of saving rates for age group, which are consistent to the life-cycle hypothesis. The saving rates of age after the middle 30s until 50s are in the rage between 30 to 38 percent. Then the rates drop after retirement. The rate over 75 years old is 1.3 percent. We also fi nd that the gap between retirement age and the starting point of public pension benefit brings drop and back of saving rates at the age of 60s

Estimation of Saving Rates by Age Group in Japan Using National Survey of Family Income and Expenditure

This paper estimates saving rates by age group in case of Japan using National Survey of Family Income and Expenditure（NSFIE）. NSFIE is a large scale survey with sample size of about 56,400 households, though it is done once in five years. We usually have saving rates of households, but those of individual are needed to investigate the effects of the decreasing birthrate and aging population on the average saving rates of macroeconomic level. This paper uses data of number of people of younger than 18 years-old, and older than or equal to 65 years-old, then estimates the saving rates by age group in the years of 1989, 1994, 1999, 2004, 2009, and 2014. Some assumptions of transfers of income within a household are set. The results show appropriate patterns of saving rates for age group, which are consistent to the life-cycle hypothesis. These patterns are also stable through years

Discrete Fr\'echet Distance Oracles

It is unlikely that the discrete Fr\'echet distance between two curves of length $n$ can be computed in strictly subquadratic time. We thus consider the setting where one of the curves, $P$, is known in advance. In particular, we wish to construct data structures (distance oracles) of near-linear size that support efficient distance queries with respect to $P$ in sublinear time. Since there is evidence that this is impossible for query curves of length $\Theta(n^\alpha)$, for any $\alpha > 0$, we focus on query curves of (small) constant length, for which we are able to devise distance oracles with the desired bounds. We extend our tools to handle subcurves of the given curve, and even arbitrary vertex-to-vertex subcurves of a given geometric tree. That is, we construct an oracle that can quickly compute the distance between a short polygonal path (the query) and a path in the preprocessed tree between two query-specified vertices. Moreover, we define a new family of geometric graphs, $t$-local graphs (which strictly contains the family of geometric spanners with constant stretch), for which a similar oracle exists: we can preprocess a graph $G$ in the family, so that, given a query segment and a pair $u,v$ of vertices in $G$, one can quickly compute the smallest discrete Fr\'echet distance between the segment and any $(u,v)$-path in $G$. The answer is exact, if $t=1$, and approximate if $t>1$

Discrete Fréchet Distance Oracles

It is unlikely that the discrete Fréchet distance between two curves of length n can be computed in strictly subquadratic time. We thus consider the setting where one of the curves, P, is known in advance. In particular, we wish to construct data structures (distance oracles) of near-linear size that support efficient distance queries with respect to P in sublinear time. Since there is evidence that this is impossible for query curves of length Θ(n^α), for any α > 0, we focus on query curves of (small) constant length, for which we are able to devise distance oracles with the desired bounds. We extend our tools to handle subcurves of the given curve, and even arbitrary vertex-to-vertex subcurves of a given geometric tree. That is, we construct an oracle that can quickly compute the distance between a short polygonal path (the query) and a path in the preprocessed tree between two query-specified vertices. Moreover, we define a new family of geometric graphs, t-local graphs (which strictly contains the family of geometric spanners with constant stretch), for which a similar oracle exists: we can preprocess a graph G in the family, so that, given a query segment and a pair u,v of vertices in G, one can quickly compute the smallest discrete Fréchet distance between the segment and any (u,v)-path in G. The answer is exact, if t = 1, and approximate if t > 1

Does Participation in the Setouchi Triennale Foster Social Capital? : A Cross-Sectional Study

This study examined whether participation in an art project was associated with higher social capital (SC). We conducted a questionnaire survey from November 2021 to March 2022 among residents aged 20 years or older of Naoshima, an island in Kagawa Prefecture, Japan. Before the survey, the Setouchi Triennale had been held on Naoshima four times, starting in 2010. We calculated propensity scores for Triennale participation and performed propensity score matching. We then compared cognitive and structural SC by Triennale participation and found significant differences, respectively. We adopted a conditional ordered logistic regression analysis with propensity score matching for cognitive or structural SC, and found adjusted odd ratios of 2.913 (95%CI, 1.846-4.596) for cognitive SC and 4.535 (95%CI, 2.839-7.244) for structural SC. Our findings suggest that Triennale participation enhanced the cognitive aspect of SC while also building structural SC

Participation in the Setouchi Triennale and the Health of Residents in Naoshima: A Cross-Sectional Study

Arts festivals have become increasingly popular in various parts of Japan in recent years. The purpose of this study was to investigate the relationships between arts festival activities participation at the Setouchi Triennale and the health of residents in the town of Naoshima. This was a cross-sectional study. Questionnaires were distributed to all residents of Naoshima who were 20 years old or older (n=2,588). We analyzed responses from 708 people. The associations between arts festival activities participation and health (measured by self-rated health) were analyzed using logistic regression analysis as the primary outcome. Kessler’s psychological distress scale scores were also analyzed in the same manner as the primary outcome. The participating group had an adjusted odds ratio of 1.86 (95% confidence interval: 1.03-3.33) for higher self-rated health compared with those who did not participate. Kessler’s psychological distress scale results showed that the participating group had an adjusted odds ratio of 3.23 (95% confidence interval: 1.19-8.81) for lower psychological distress compared with those who did not participate. In conclusion, arts festival activities participation was associated with higher self-rated health and lower psychological distress. However, caution must be taken in regard to generalizability and causality when interpreting these results

Spatiotemporal Control of Ice Crystallization in Supercooled Water via an Ultrashort Laser Impulse

Takahashi H., Kono T., Sawada K., et al. Spatiotemporal Control of Ice Crystallization in Supercooled Water via an Ultrashort Laser Impulse. Journal of Physical Chemistry Letters, 14(19), 4394-4402, 18 May 2023: © 2023 American Chemical Society. DOI: 10.1021/acs.jpclett.3c00414.Focused irradiation with ultrashort laser pulses realized the fine spatiotemporal control of ice crystallization in supercooled water. An effective multiphoton excitation at the laser focus generated shockwaves and bubbles, which acted as an impulse for inducing ice crystal nucleation. The impulse that was localized close to the laser focus and accompanied by a small temperature elevation allowed the precise position control of ice crystallization and its observation with spatiotemporal resolution of micrometers and microseconds using a microscope. To verify the versatility of this laser method, we also applied it using various aqueous systems (e.g., plant extracts). The systematic study of crystallization probability revealed that laser-induced cavitation bubbles play a crucial role in inducing ice crystal nucleation. This method can be used as a tool for studying ice crystallization dynamics in various natural and biological phenomena