On strategy-proofness and essentially single-valued cores: A converse result

In a general model of indivisible good allocation, S?nmez (1999) established that, whenever the core is nonempty for each preference profile, if an allocation rule is strategy-proof, individually rational and Pareto optimal, then the rule is a selection from the core correspondence, and the core correspondence must be essentially single-valued. This paper studies the converse claim of this result. I demonstrate that whenever the preference domain satisfies a certain condition of `richness', if the core correspondence is essentially single-valued, then any selection from the core correspondence is strategy-proof (even weakly coalition strategy-proof, in fact). In particular, on the domain of preferences in which each individual has strict preferences over his own assignments and there is no consumption externality, such an allocation rule is coalition strategy-proof. And on this domain, coalition strategy-proofness is equivalent to Maskin monotonicity, an important property in implementation theory. Received: 22 February 2000/Accepted: 22 January 2002 I am grateful to Ryo-ichi Nagahisa, Shinji Ohseto, Hiroshi Ono, Tomoichi Shinotsuka and Shigehiro Serizawa for valuable comments. And I am indebted to two anonymous referees for useful suggestions. Especially, I owe the present proof of Lemma 2 to one referee. I also thank Yukihiko Funaki, Atsushi Kajii, Mamoru Kaneko, Eiichi Miyagawa, Tatsuyoshi Saijo, Manimay Sengupta, Yves Sprumont, Yoshikatsu Tatamitani, Manabu Toda, Takashi Ui, Takehiko Yamato, Naoki Yoshihara and the participants of the seminars in Hokkaido University, Kansai University, ISER (Osaka University), Otaru University of Commerce and Tsukuba University. All errors are my own responsiblity.     

Development of the workflow kine systems for support on KAIZEN

In this paper, we introduce the new workflow line system consisted of the location and image recording, which led to the acquisition of workflow information and the analysis display. From the results of workflow line investigation, we considered the anticipated effects and the problems on KAIZEN. Workflow line information included the location information and action contents information. These technologies suggest the viewpoints to help improvement, for example, exclusion of useless movement, the redesign of layout and the review of work procedure. Manufacturing factory, it was clear that there was much movement from the standard operation place and accumulation residence time. The following was shown as a result of this investigation, to be concrete, the efficient layout was suggested by this system. In the case of the hospital, similarly, it is pointed out that the workflow has the problem of layout and setup operations based on the effective movement pattern of the experts. This system could adapt to routine work, including as well as non-routine work. By the development of this system which can fit and adapt to industrial diversification, more effective "visual management" (visualization of work) is expected in the future.     

Geographical variation of elytral spot patterns in the phytophagous ladybird,Epilachna vigintioctopunctata (Coleoptera: Coccinellidae) in the Province of Sumatera Barat, Indonesia

Summary Geographical variation in the elytral spot patterns of a phytophagous ladybird,Epilachna vigintioctopunctata, was studied in the Province of Sumatera Barat, Indonesia. Populations ofE. vigintioctopunctata were divided into four major groups (I–IV) by the incidence of spot pattern variations. Group I, occurring in the coastal plains and inland lowlands, and Group IV, confined to the highlands, were the extremes of the spot pattern variations, the latter had many more non-persistent spots and confluences with larger body size and advanced melanism than the former. These two groups were connected with each other via the intermediate groups. A positive relationship was detected between the elevations of sample sites and the average number of non-persistent spots per elytron. Consequently, present results favor the view that the two previously recognized forms ofE. vigintioctopunctata (formae A and B inKatakura et al., 1988) represent a complicated intraspecific variation rather than two distinct sibling species. Elytral spot pattern variations were not different between the sexes or between the beetles collected from different kinds of host plants. Contribution No. 30 of Sumatra Nature Study (Entomology). Supported in part by grants from Japan Society for the Promotion Science for JSPS-DGHE Scientific Cooperation (1980, 1982) and for the RONPAKU program (toI. Abbas, 1984) and Grants-in-Aid for Overseas Scientific survey from the Ministry of Education, Science and Culture of Japan (Nos. 56041027 and 58041030).     

飞行时间太赫兹断层成像

介绍了利用超短激光脉冲的高分辨飞行时间太赫兹断层成像的发展。其基本原理是,首先非线性光学晶体获得的宽带太赫兹脉冲进入到样品,随后检测每一层反射回来的回波脉冲。利用高斯窗口的去卷积过程我们可以获得清晰、高分辨的断层成像谱图。与聚四氟乙烯薄膜机械厚度测量的结果比较,如果一个样品的折射率为n,则轴向分辨率低于10/nμm。     

Dopamine and risk choices in different domains: Findings among serious tournament bridge players

We explore how risk-taking in the card game contract bridge, and in a financial gamble, correlate with variation in the dopamine receptor D4 gene (DRD4) among serious tournament bridge players. In bridge risk-taking, we find significant interactions between genetic predisposition and skill. Among men with the 7-repeat allele of DRD4, namely 7R + men, those with more bridge skill take more good risks and fewer bad risks, while the opposite is found for less-expert 7R + men. Conversely, skill does not predict risk-taking among men without the 7R + allele. Consistent with some prior studies, we also find that 7R + men take more risk in the financial gamble. We find no relationship between 7R + and either risk measure among our female subjects. Our results suggest that the dopamine system plays an important role in individual differences in risk-taking among men, and is the first to distinguish between advantageous and disadvantageous risk-taking.     

Adult population parameters and life tables of an epilachnine beetle (Coleoptera: Coccinellidae) feeding on bitter cucumber in Sumatra

Summary The population dynamics of an epilachnine beetle, which is closely related toEpilachna sparsa Dieke (henceforth called “sp. C”) and feeds on bitter cucumberMomordica charantia, was studied by mark-recapture of adults and the construction of life tables. The study was repeated three times, i.e., March–May, July–September and October–December in 1982, in Padang, Sumatra, Indonesia. After the establishment of the host plants, adults of “sp. C” soon colonized, and each study period ended in the death of the plants due to defoliation by the larvae and adults. The estimated mean length of residence of adults ranged from 6–11 days, but this was probably much shorter than the actual longevity, because the adults were so active that they flew away, or dropped off the plants, when they were approached or slightly disturbed. Life tables indicated that egg mortality ranged from 17.8–53.9%, and a parasitic waspTetrastichus sp. B made up 41.1–64.2% of egg mortality. Two wasps,Tetrastichus sp. C andPediobius foveolatus killed 1.2–19.4% (7.6–100%)^* of 4th instars and only the latter species attacked the pupae, killing 24.6–59.1% (45.1–72.4%). Parasitism and starvation by overcrowding contributed most to the total mortality from egg to adult emergence, which ranged from 89.4–99.5%. “Sp. C” had a higher diversity and level of parasitism than the Japanese species,E. vigintioctopunctata. The high dispersal power of “sp. C”, coupled with the prolongedl _x−m_x schedules shown under laboratory conditions, was advantageous for exploiting the food plant which was available throughout the year, but was rather patchily distributed in space.     

PERCEPTIONS OF SOCIAL SUPPORT AVAILABILITY AND COPING BEHAVIORS AMONG GAY MEN WITH HIV

Analyzing face-to-face, semistructured interviews, we discuss how perceptions of social support availability are formed among gay men coping with HIV. Experiences of receiving support increased perceived availability for specific types of support from specific individuals, but receiving support also gave these men a general sense that someone would be available for assistance. Other aspects of social relationships, such as closeness and role expectations, contributed to gay men's perceptions of support availability. The results suggest that when people with common problems cope together, collective knowledge of support availability may emerge from observations of others' support exchanges as well as from discussions of support experiences. Individuals or groups of individuals may actively create and modify their perceptions of support availability when they cope with anticipated problems. Thus, the study provided an opportunity to integrate concepts of coping and social support into the collective action and social constructionist frameworks.     

COVID-19 Pandemic and Non-standard Employees in Japan

This article aims to grasp the influence of the pandemic on standard and non-standard employees in Japan and clarify its disparity between them. In 2020, there was an imbalance between the slight increase in standard employees and the massive loss of non-standard employees in the labour market. Non-standard employees' working hours were greatly reduced, often without allowances for absence, and hence their monthly income considerably diminished. As a result, their well-being also declined. Thus, the pandemic has affected employment, and its impact has been felt most strongly by non-standard employees. This does not mean that there is no discriminatory treatment of non-standard employees in firms. However, a closer look at the real picture reveals a variety of factors. In addition to the discriminatory treatment that is related to the Japanese employment system, a combination of managerial factors such as the shortage of standard employees, practical factors such as differences in wage systems, and the lack of sufficient information about the expansion of the coverage of the Employment Adjustment Subsidy, have placed non-standard employees at a huge disadvantage.