Process generating the ditribution pattern of eggs of the common cabbage butterfly,Pieris rapae crucivora

Summary The process generating the negative binomial in the distribution pattern of eggs of the common cabbage butterfly,Pieris rapae crucivora, was investigated by releasing the female adults in a net house where cabbages were planted. The distribution of butterflies visited and laid an egg or more per plant followed thePoisson series under the uniform light condition, while that of eggs laid per visit conformed to the logarithmic distribution. From these results, it may be concluded that the negative binomial arises from compounding of thePoisson and the logarithmic distribution. The observed frequency of eggs found per plant fitted to the negative binomial with parameter thus computed theoretically. The change in the degree of aggregation with the increase of the parental density was considered in connection with the above results. Aided by a grant from Scientific Research Expenditure of the Ministry of Education.     

EVOLUTION AND SPONTANEOUS UNIFORMITY: EVIDENCE FROM THE EVOLUTION OF THE LIMITED LIABILITY COMPANY

We examine whether the unguided state-by-state evolution of limited liability company statutes has led to efficient interstate uniformity. Our evidence suggests significant uniformity has been produced in cases where the net benefits of uniformity are positive, and that such uniformity has not been produced by herd behavior. Our results are consistent with Alchian's intuition about the role of market processes, and suggests that the survival of efficient rules, fostered by the rational behavior of decentralized economic actors, are produced by forces beyond the control or foresight of individual lawmakers or legislatures.     

Gender,Social Bond,and Academic Cheating in Japan*

There is evidence that females are less likely to cheat than males on college campuses. A frequently offered but still untested explanation is that females, with a stronger sense of responsibility for the maintenance of social relationships, tend to develop a stronger bond to a conventional society—a key explanatory concept in Hirschi’s (1969) social control theory. With academic cheating as the dependent variable, we test the hypotheses that the four elements of social bond are the intervening variables linking gender to such dishonesty among Japanese students who, due to their stronger orientation toward masculinity on Hofstede’s (1980) scale of gender role separation, are subject to more gender distinct socialization, leading to greater gender differences in the strength of social bond than those previously reported in the United States. The analysis provides rather limited support for the theory, most of which is due to the stronger belief in the legitimacy of societal rules among the females.     

Estimation of Benchmark Dose as the Threshold Amount of Alcohol Consumption for Blood Pressure in Japanese Workers

In order to determine the threshold amount of alcohol consumption for blood pressure, we calculated the benchmark dose (BMD) of alcohol consumption and its 95% lower confidence interval (BMDL) in Japanese workers. The subjects consisted of 4,383 males and 387 females in a Japanese steel company. The target variables were systolic, diastolic, and mean arterial pressures. The effects of other potential covariates such as age and body mass index were adjusted by including these covariates in the multiple linear regression models. In male workers, BMD/BMDL for alcohol consumption (g/week) at which the probability of an adverse response was estimated to increase by 5% relative to no alcohol consumption, were 396/315 (systolic blood pressure), 321/265 (diastolic blood pressure), and 326/269 (mean arterial pressures). These values were based on significant regression coefficients of alcohol consumption. In female workers, BMD/BMDL for alcohol consumption based on insignificant regression coefficients were 693/134 (systolic blood pressure), 199/90 (diastolic blood pressure), and 267/77 (mean arterial pressure). Therefore, BMDs/BMDLs in males were more informative than those in females as there was no significant relationship between alcohol and blood pressure in females. The threshold amount of alcohol consumption determined in this study provides valuable information for preventing alcohol-induced hypertension.     

Benchmark Duration of Work Hours for Development of Fatigue Symptoms in Japanese Workers with Adjustment for Job‐Related Stress

The objective of this study was to calculate benchmark durations and lower 95% confidence limits for benchmark durations of working hours associated with subjective fatigue symptoms by applying the benchmark dose approach while adjusting for job‐related stress using multiple logistic regression analyses. A self‐administered questionnaire was completed by 3,069 male and 412 female daytime workers (age 18–67 years) in a Japanese steel company. The eight dependent variables in the Cumulative Fatigue Symptoms Index were decreased vitality, general fatigue, physical disorders, irritability, decreased willingness to work, anxiety, depressive feelings, and chronic tiredness. Independent variables were daily working hours, four subscales (job demand, job control, interpersonal relationship, and job suitability) of the Brief Job Stress Questionnaire, and other potential covariates. Using significant parameters for working hours and those for other covariates, the benchmark durations of working hours were calculated for the corresponding Index property. Benchmark response was set at 5% or 10%. Assuming a condition of worst job stress, the benchmark duration/lower 95% confidence limit for benchmark duration of working hours per day with a benchmark response of 5% or 10% were 10.0/9.4 or 11.7/10.7 (irritability) and 9.2/8.9 or 10.4/9.8 (chronic tiredness) in men and 8.9/8.4 or 9.8/8.9 (chronic tiredness) in women. The threshold amounts of working hours for fatigue symptoms under the worst job‐related stress were very close to the standard daily working hours in Japan. The results strongly suggest that special attention should be paid to employees whose working hours exceed threshold amounts based on individual levels of job‐related stress.     

Family structure and well-being at older ages in Japan

The family structure of older Japanese is projected to change dramatically as a result of very low fertility, increasing levels of non-marriage, childlessness, and divorce, and declining intergenerational co-residence. To provide an empirical basis for speculation about the implications of projected increases in single-person and couple-only households, we use two sources of data to describe relationships between family structure and the physical and emotional well-being of Japanese men and women aged 60 and above. We find that marriage is positively associated with self-rated health and emotional well-being among older men but not women. In contrast to expectations, however, we find only limited evidence that the presence of children contributes to well-being. Taken as a whole, our results suggest that declines in marriage may have negative implications for the well-being of older Japanese men while the implications of declines in fertility and intergenerational co-residence may be less than popularly believed.     

Relative Income and Happiness in Asia: Evidence from Nationwide Surveys in China, Japan, and Korea

This study attempts to examine relative income effects on perceived happiness in three major Asian countries—China, Japan, and Korea—in comparison with the United Sates, on the basis of largely comparable nationwide surveys in these countries. Consistent with the results from previous studies in Western countries, comparisons with an individual’s own income and average income of the reference group are significantly associated with the individual’s perceived happiness in Asia. The associations between relative income and happiness are stronger for individual income than family income in China, while the opposite is true in Japan and Korea. Even after controlling for the subjective assessment of family income or personal class identification within the society as a whole, income comparisons within the reference group matter for assessing happiness, especially when using family income for comparisons. Moreover, relative deprivation within the reference group, which is measured by the Yitzhaki index, is negatively related to happiness, providing more evidence for the validity of the relative income hypothesis.