Social Stratification and the Division of Household Labor in Japan: The Effect of Wives' Work on the Division of Labor among Dual-earner Families

Abstract:  This article explores the relationship between social stratification and the division of household labor by examining how the contribution to housework by husbands in dual-earner families varies across the Japanese social stratification structure. First, I review previous studies concerning the determinants of husbands' participation in housework and construct four hypotheses regarding the relative resources explanation, the time constraints explanation, the ideology/sex role explanation, and the alternative manpower explanation. Second, I examine the empirical support for these hypotheses in dual-earner couples and the effect of social stratification on husband's participation in housework, which has not been studied thus far. Third, I investigate the effect of social stratification in more detail. According to the results of TOBIT regressions and other supplementary analyses, the principal findings are as follows:

• 1) 

  the relative resources explanation is not supported;

       

Robust Bayesian model selection for variable clustering with the Gaussian graphical model

Statistics and Computing - Variable clustering is important for explanatory analysis. However, only few dedicated methods for variable clustering with the Gaussian graphical model have been...     

Economic Opportunities and the Division of Labor among Japanese Immigrant Couples in Southern California*

Based on 36 in‐depth interviews conducted with 18 Japanese couples who live in Southern California, this study examines the impact of differential economic opportunities on the division of labor among Japanese immigrant couples. Three main factors facilitate Japanese professional and businessmen’s mobility to and settlement in Southern California: (1) the gender‐based stratification of the workplace in Japan; (2) U.S. immigration policies that favor foreign nationals with strong corporate ties and business experience; and (3) the strong presence of Japanese corporations in Southern California. Whereas these conditions enable men to maintain their earning power, they do not benefit women in employment opportunities. The difference in economic opportunities encourages Japanese couples to preserve a breadwinner and homemaker division of labor, and women continue to do a bulk of housework and childcare even when women reenter the labor force later in their lives.     

Age related variation of salivary testosterone values in healthy Japanese males

Objective. We examined age associated variation in salivary testosterone values among Japanese males as well as anthropometric measurements.

Methods. Salivary samples were collected in pretreated sodium azide treated tubes. The first series: 15–79-year-old males (n = 99); two morning and two evening samples were collected at home for two days. The second series: 90-year-old males (n = 29); one morning sample was collected. Testosterone values were determined using an iodine125-based radioimmunoassay kit modified for saliva.

Results. Results show 1) a significant decrease in salivary testosterone values from 20s to 40s and older, 2) no significant decline after 40 through 90 years old, 3) no significant age-related differences in the degree of intraindividual diurnal fluctuation across age groups of 40–70s, and 4) higher BMI is associated with the lower salivary testosterone among 40–70s.

Conclusions. These results suggest that neither a constant decrease of salivary testosterone values or markedly reduced intraindividual fluctations are universal aspects of aging. Older males may maintain relatively high testosterone levels compared to younger men and a relatively ‘robust’ neuroendocrinological system.     

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.     

Fate of a mutant emerging at the initial stage of evolution

A simple system was constructed and used in the experimental elucidation of the fate of a mutant emerging in a population. ThreeEscherichia coli strains having the same genetic background except for their glutamine synthetase gene were used as model competitors. The difference in the enzyme gene were introduced by random mutation. Competition between these bacterial strains was carried out and observed in a continuous liquid culture. In most cases, the competitors stably coexist either in a steady state or in an oscillating state. In addition, the competition between the strains was found to be a deterministic process and not a stochastic one. These results showed that an emerging mutant in a population, be it a closely related one to the original members, can attain a state of stable coexistence even in a homogeneous environment. The ability of each of the emerging mutants to maintain its stable coexistence with the original population gives rise to the accumulation of various mutants in a population. Therefore, evolution starts from gradual accumulation of various mutants in the population, which in turn leads to the diversification of the population. As our experimental system is a minimum model for the various competitions in the natural ecosystem, the observed competitive coexistence is proposed to be a general phenomenon in nature.     

The role of the brown-eared bulbulHypsypetes amaurotis as a seed dispersal agent

The role of the brown-eared bulbul,Hypsypetes amaurotis, as a dispersal agent for seeds of fruiting plants was studied by field observations for two years, in parallel with laboratory experiments on seed germination. Bulbuls consumed fruits of 53 species from 24 plant families. The fruits of these plants had similar color and size, and these characteristics were likely to enhance the feeding efficiency of the frugivore. Laboratory experiments on 20 food plant species demonstrated that: (1) no seeds were injured by passing through the bulbul's gut; (2) seeds that had passed through the bulbul's gut were still able to germinate and (3) fruit pulp reduced germination ability. When pulp was removed by passing through bulbul's gut, or by hand, germination was improved. An estimate of the home range of six bulbuls suggested that they may transport seeds for at least 300 m.     

Bystander Attitudes to Prevent Sexual Assault: A Study of College Students in the United States,Japan, India,Vietnam, and China

College women are at a high risk of sexual assault. Although programs that aim to change bystander behaviors have been shown to be potentially effective in preventing sexual assault on campuses in the United States, little is known about bystander behaviors outside of the United States. The purpose of this study was to explore and compare factors affecting bystander behaviors regarding sexual assault intervention and prevention among undergraduate students in the United States, Japan, India, Vietnam, and China. A total of 1,136 students participated in a self-reported survey. Results demonstrate substantial variations across countries. Bystander behaviors are associated with multilevel factors, including gender, knowledge of individuals who have experienced a sexual assault, and knowledge about campus or community organizations.     

Assessment of community food resources: A Latino neighborhood study in upstate New York

This study aims to assess availability, affordability, and accessibility of food items in a low-income Latino neighborhood within a small city using an on-site food store survey. Store locations were identified by on-site GPS. Results showed the Latino neighborhood had limited availability and above average cost of high-fiber bread. Fresh vegetables were more expensive compared to the non-Latino neighborhood, and more stores in the Latino neighborhood participated in Supplemental Nutrition Assistance Food Program. The lack of supermarkets, fewer stores with disability access, and the lack of public transportation left Latino residents without a vehicle or with physical disabilities with few food shopping options.