A polynomial-time perfect sampler for the <Emphasis Type="Italic">Q</Emphasis>-Ising with a vertex-independent noise

We present a polynomial-time perfect sampler for the Q-Ising with a vertex-independent noise. The Q-Ising, one of the generalized models of the Ising, arose in the context of Bayesian image restoration in statistical mechanics. We study the distribution of Q-Ising on a two-dimensional square lattice over n vertices, that is, we deal with a discrete state space {1,…,Q} ⁿ for a positive integer Q. Employing the Q-Ising (having a parameter β) as a prior distribution, and assuming a Gaussian noise (having another parameter α), a posterior is obtained from the Bayes’ formula. Furthermore, we generalize it: the distribution of noise is not necessarily a Gaussian, but any vertex-independent noise. We first present a Gibbs sampler from our posterior, and also present a perfect sampler by defining a coupling via a monotone update function. Then, we show O(nlog n) mixing time of the Gibbs sampler for the generalized model under a condition that β is sufficiently small (whatever the distribution of noise is). In case of a Gaussian, we obtain another more natural condition for rapid mixing that α is sufficiently larger than β. Thereby, we show that the expected running time of our sampler is O(nlog n).     

Measure of departure from symmetry for the analysis of collapsed square contingency tables with ordered categories

For square contingency tables with ordered categories, there may be some cases that one wants to analyze them by considering collapsed tables with some adjacent categories combined in the original table. This paper considers the symmetry model for collapsed square contingency tables and proposes a measure to represent the degree of departure from symmetry. The proposed measure is defined as the arithmetic mean of submeasures each of which represents the degree of departure from symmetry for each collapsed 3×3 table. Each submeasure also represents the mean of power-divergence or diversity index for each collapsed table. Examples are given.     

Yearlong physical activity and health-related quality of life in older Japanese adults: the Nakanojo Study

We hypothesized that the health-related quality of life (HRQOL) would be poorer in physically inactive older adults. This was tested in a sample of 73 male and 108 female free-living healthy Japanese participants, age 65-85 years. We measured accelerometer step counts and their metabolic equivalents (METs) throughout each 24-hr period for 1 year. At the end of the year, HRQOL was assessed. Physical activity was grouped into quartiles. HRQOL was poorer in the lowest quartiles of participants with respect to both step count and duration of activity >3 METs; however, our sample showed no better HRQOL in those participants exceeding minimum standards of daily physical activity, corresponding to counts of around 5,500 and 4,500 steps/day and durations of around 13 and 14 min/day in men and women, respectively. Causation cannot be demonstrated from this cross-sectional study, but nevertheless we suggest that elderly individuals should be encouraged to meet such standards of habitual physical activity.     

Potential roles of small and linear habitat fragments in satoyama landscapes for conservation of grassland plant species

By comparing with the historic semi-natural grassland and woodland vegetation data compiled in the 1970s and 1980s, we aimed to reveal potential roles of small and linear habitat fragments remaining in the urbanized satoyama landscape (i.e., agricultural landscape) in Japan for conservation of grassland plant species. TWINSPAN cluster analysis differentiated the current vegetation from historic one. Current vegetation of Miscanthus grassland was classified into two different groups and one of the two was equivalent to current understory vegetation of fragmented woodland. The linear woodland edge vegetation along the roads was classified into one group and separated from the other current vegetation groups. The current vegetation groups were characterized by higher richness of exotic species than historic vegetation groups. Detrended correspondence analysis (DCA) revealed that there were no groups of current vegetation that is equivalent to historic woodland understory vegetation. The vegetation quality of the current group of Miscanthus grassland and secondary woodland remaining on urban public properties, and the group of linear roadside vegetation were almost equivalent to that of historic semi-natural grassland. Both of the small and linear habitat fragments might have functioned as habitats for grassland species under regular mowing management. Although small and linear habitat fragments would not be sufficient for sustaining grassland populations in the future, these habitats can serve as key reservoirs for grassland species recovery in the conservation and restoration of grassland communities in the urbanized satoyama landscape.     

Crime news,fear of crime,and mistrust: an examination of protective factors against influences of local crime news

This study investigates interpersonal communication ties and a neighborhood context as moderators of the influences of local crime news on fear of crime and mistrust. Data from a web survey of residents in Chicago show that the relationship between attention to local crime news and fear of crime is weaker for respondents who more frequently communicate with neighbors both intimately and casually and who live in more walkable neighborhoods. Data also indicate that the relationship between local crime news and mistrust is weaker for those who more often communicate with neighbors intimately and live in more walkable neighborhoods. Findings are discussed in terms of protective factors against the negative influences of local crime news.     

Newcomer Migrant Workers in the Underclass: A Yokohama, Japan Case Study

Abstract  This paper will investigate how some undocumented migrant workers survive in Kotobuki, Yokohama known as the urban underclass. Since the latter half of the 1990s, Kotobuki itself has undergone structural changes. Once a center of day laborers it is now a center of older ex-laborers, mostly surviving on welfare. However, Kotobuki holds positive associations for many Korean and Pilipino migrants, many of whom arrived at the end of the 1980s. They regard the area as a place to earn high wages and as a center for building ethnic networks. Migrants tend to help their ethnic fellows find jobs and exchange information that they may otherwise be unable to acquire given that undocumented migrants are ineligible for public services in Japan. Additionally, ethnic-related self-help activities as well as NGOs play a valuable role in sustaining the livelihood of such migrants who are denied access to public services and assistance. This paper will illustrate the role of self-help among ethnic minority migrant workers. It also aims to demonstrate that contrary to prevailing assumptions, their social status as underclass is not lower than that of their Japanese counterparts.     

Smokers’ Sexual Behavior and Their Satisfaction with Family Life

Smokers tend to be more impatient and prefer immediate benefits compared with non-smokers. If people follow their primitive instincts they will engage in sexual behavior. Impatient people are more likely to have sex. However, for married people, having sex with a spouse is considered to be an investment in family life. Based on individual level data of Japan General Social Surveys, this paper investigated how sexual behavior differs between smokers and non-smokers. In addition to it, determinants of life satisfaction are also investigated. The important findings through the interval regression model and the ordered probit model are: (1) frequency of sex is positively associated with family satisfaction; (2) unmarried smokers are more likely to have sex than unmarried non-smokers; (3) married smokers are less likely to have sex than married non-smokers. It follows from estimation results that smoking behavior alerts us to his unobserved characteristics before marriage, thus reducing information asymmetry.     

Variety expansion and fertility rates

To investigate how fertility rates interrelate with the modern economy, we construct a simple model in which variety expansion of consumption goods reduces fertility rates. In our model, variety expansion reduces the relative price of a composite of differentiated goods compared to child-rearing costs. Thus, parents raise the expenditure share for differentiated goods and lower the number of children. We show that this model can be applied to a growth model in which economic growth progresses with variety expansion of consumption goods and fertility rates decrease with economic growth. Thus, we show a new mechanism for fertility decline, and this mechanism can be applied to a growth model.     

Socio-economic determinants of suicide in Japan

Japan has the highest suicide rates among the OECD countries and this public health problem seems to be accelerating in over the recent decades. Investigating and understanding the suicidal behaviour is of crucial importance to society and health policy makers. Such an investigation could provide with useful information for those responsible in formulating the national policies on suicide prevention. This study estimates dynamic econometric models for total, male and female suicides in Japan for the period of 1957–2009. Using the ARDL approach to cointegration, we find that the associations of suicide with sociological factors (divorce and fertility rates) were stronger than those with economic factors (per capita GDP and unemployment) for females.