Aging, fertility, social security and political equilibrium

We analyze the effect of population aging on the political choice of the size of a pay-as-you-go (PAYG) social security system, incorporating the heterogeneity of individuals in their preference for having children, and hence the endogenous fertility choices of individuals, into a simple overlapping generations model. We show that population aging may result in an increase in the contribution rate, increasing the share of the retired population who prefer a higher contribution rate; and that, if the system involves redistribution between retirees with different contributions, the increased contribution rate raises the number of individuals who have children, i.e., future contributors.     

Fertility, child care outside the home, and pay-as-you-go social security

We examine the long-run effects of the pay-as-you-go (PAYG) social security scheme on fertility and welfare of individuals in an overlapping generations model, assuming that child-care services are available in the market. We show that the impact of a tax increase on fertility depends on the relative magnitudes of the standard intergenerational redistribution effect through the social security system, the (implicit) subsidy effect through tax-exemption of child rearing at home, and the price effect through changes in the relative price of market child care, and that if parental child-rearing time is inelastic, a tax cut could bring about a Pareto-improving allocation.

Uncertain lifetime, fertility and social security

Investigating the effects of population aging on fertility and economic growth, we show that an increase in life expectancy lowers the fertility rate and raises life-cycle savings, and that a pay-as-you-go social security does not reverse the effect on fertility. Received: 10 March 2000/Accepted: 28 April 2000     

SEASONAL INTEGRATION FOR DAILY DATA

This paper has two purposes: it introduces the econometric methods used to analyze time series data with general frequency and presents a framework for analyzing economic variables that are measured daily; this special case is then applied to the trading volume of stock markets.     

大学教授职的研究意向和教育意向的国际动向

文章通过对比分析1992年卡内基基金会与2007年CAP的关于大学教授职的国际调查发现,无论是研究意向与教育意向均衡的盎格鲁撒克逊型,还是以教育意向为主的拉丁美洲型大都削弱了教育意向,在不断地向以研究意向为主的德国型转变。其中,只有美国依旧停留在极强的教育意向型中。通过对研究意向理由的分析可知,学术观正在从纯粹的科学向应用科学转移。从对教育和研究的并行性实态的国际比较与分析可知,研究意向高的国家存在并行困难性高的倾向。据此得出,以教育与研究相统一、乃至"研究—教育—学习"统一为理念的洪堡模式正在倒退。     

Effects of capital taxation on economies with different demographic changes: short term versus long term

We examine the effect of source-based capital taxation on capital accumulation in countries with endogenous fertility and free international capital mobility. When fertility is constant, a tax cut accelerates domestic capital accumulation through international arbitrage and exerts negative influences on the welfare of a foreign country. In contrast, with endogenous fertility, a tax cut by an economy with a higher tax rate and exporting capital may deter capital accumulation and hence lower the welfare in not only domestic but also foreign economies in the long term, although the tax cut may accelerate domestic capital accumulation in the short term.     

Reconfiguration of dominating sets

We explore a reconfiguration version of the dominating set problem, where a dominating set in a graph G is a set S of vertices such that each vertex is either in S or has a neighbour in S. In a reconfiguration problem, the goal is to determine whether there exists a sequence of feasible solutions connecting given feasible solutions s and t such that each pair of consecutive solutions is adjacent according to a specified adjacency relation. Two dominating sets are adjacent if one can be formed from the other by the addition or deletion of a single vertex. For various values of k, we consider properties of \(D_k(G)\), the graph consisting of a node for each dominating set of size at most k and edges specified by the adjacency relation. Addressing an open question posed by Haas and Seyffarth, we demonstrate that \(D_{\varGamma (G)+1}(G)\) is not necessarily connected, for \(\varGamma (G)\) the maximum cardinality of a minimal dominating set in G. The result holds even when graphs are constrained to be planar, of bounded tree-width, or b-partite for \(b \ge 3\). Moreover, we construct an infinite family of graphs such that \(D_{\gamma (G)+1}(G)\) has exponential diameter, for \(\gamma (G)\) the minimum size of a dominating set. On the positive side, we show that \(D_{n-\mu }(G)\) is connected and of linear diameter for any graph G on n vertices with a matching of size at least \(\mu +1\).     

ARE SUNK COSTS IRRELEVANT? EVIDENCE FROM PLAYING TIME IN THE NATIONAL BASKETBALL ASSOCIATION

We use playing time in the National Basketball Association to investigate whether sunk costs affect decision making. Behavioral economics implies that teams favor players chosen in the lottery and first round of the draft because of the greater financial and psychic commitment to them. Neoclassical economics implies that only current performance matters. We build on previous work in two ways. First, we better capture potential playing time by accounting for time lost to injuries or suspension. Second, we use regression discontinuity to capture changes when a player's draft position crosses thresholds. We find that teams allocate no more time to highly drafted players. (JEL L83, J23, D03)     

Current Implementation of and Opinions and Concerns Regarding Suicide Education for Social Work Undergraduate Students in Japan: A Cross-Sectional Study

This study explored the current implementation status of and opinions and concerns regarding suicide education at schools of social work in Japan. We conducted a survey of faculty members who taught at least one of the social work subjects. About half the respondents had given a lecture of some kind on suicide, and more than 80% agreed that suicide is an important topic to include in social work program curricula. However, more than half indicated they did not have enough knowledge or skills to teach students about suicide, and more than 60% were concerned about adverse psychological effects of suicide education on students. Our findings highlight the importance of providing faculty members with guidelines for teaching students about suicide.     

Effects of 10-week walking and walking with home-based resistance training on muscle quality,muscle size,and physical functional tests in healthy older individuals

Background

Older individuals have been shown to present muscle atrophy in conjunction with increased fat fraction in some muscles. The proportion of fat and connective tissue within the skeletal muscle can be estimated from axial B-mode ultrasound images using echo intensity (EI). EI was used to calculate the index of muscle quality. Walking, home-based weight-bearing resistance training, and its combinations are considered simple, easy, and practical exercise interventions for older adults. The purpose of this study was to quantify the effects of walking and walking with home-based resistance training on muscle quality of older individuals.

Methods

Thirty-one participants performed walking training only (W-group; 72?±?5?years) and 33 participants performed walking and home-based resistance training (WR-group; 73?±?6?years). This study was a non-randomized controlled trial with no control group. All participants were instructed to walk 2 or 3 sets per week for 10?weeks (one set: 30-min continuous walking). In addition, the WR-group performed home-based weight-bearing resistance training. EI was measured as a muscle quality index using axial B-mode ultrasound images of the rectus femoris and vastus lateralis of the mid-thigh. We further averaged these parameters to obtain the EI of the quadriceps femoris (QF). Participants further performed five functional tests: sit-ups, supine up, sit-to-stand, 5-m maximal walk, and 6-min walk.

Results

QF EI was significantly decreased in both groups after training (W-group 69.9?±?7.4?a.u. to 61.7?±?7.0?a.u., WR-group 64.0?±?9.5?a.u. to 51.1?±?10.0?a.u.; P?<?0.05), suggesting improved muscle quality. QF EI was further decreased in the WR-group compared with the W-group. The sit-up test in both groups and the sit-to-stand and 5-m maximal walk tests in the W-group were significantly improved after training.

Conclusion

These results suggest that training-induced stimulation is associated with a decrease in EI in some thigh regions. Furthermore, the addition of home-based resistance training to walking would be effective for a greater reduction of EI.