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     

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)     

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.

     

Toward an Alternative Analytic Approach to the Internal Politics of Unions

Abstract  This paper discusses theoretical issues in analyzing the internal politics of unions in Japan. The main argument is that the autonomy of unions' internal political processes from management should not be assumed and that the very development of internal politics of unions may be influenced by the actors with which the unions interact. The paper first reviews previous research on the internal politics of unions in Western countries and discusses a model of internal union politics based on these studies. Second, it reviews previous studies of enterprise unions in Japan and considers why these studies have been indifferent to the internal politics. Third, the paper proposes an alternative approach to internal union politics by synthesizing insights from previous studies of unions and union politics in Western countries and Japan. The approach is based on the concept of the "political space" of unions. Fourth, application of the alternative approach to the development of internal politics of the enterprise union of Yahata Steel (from 1970, Nippon Steel), the largest steel firm in Japan, shows how the union's political space has become more narrow over time. Finally, the paper concludes by noting the relevance of the proposed approach to studies of union-management relations in other industrialized countries.     

Incremental optimization of independent sets under the reconfiguration framework

Journal of Combinatorial Optimization - Suppose that we are given an independent set $$I_0$$ of a graph G, and an integer $$l\ge 0$$ . Then, we are asked to find an independent set of G having the...