Double shrink methodologies to determine the sample size via covariance structures

We consider fixed-size estimation for a linear function of mean vectors from _πi:_Np(_μi,_Σi)${\pi }_i:{\mathrm{N}}_p({\mathit{\mu }}_i,{\mathbf{\Sigma }}_i)$, i=1,…,k$i=1,\dots ,k$, when every _Σi${\mathbf{\Sigma }}_i$ has some structure. The goal of inference is to construct a fixed-span confidence region with required accuracy. We find a sample size for each _πi${\pi }_i$ with the help of the ‘double shrink methodology’, that is introduced by this paper, via covariance structures of _Σi${\mathbf{\Sigma }}_i$, i=1,…,k$i=1,\dots ,k$. We estimate the sample size in a two-stage sampling and give a fixed-span confidence region that has the coverage probability approximately second-order consistent with the required accuracy. Some simulations are carried out to see moderate sample size performances of the proposed methodologies.     

A DESIGN OF NORMATIVE SOCIOLOGY BASED ON THE RATIONAL CHOICE PARADIGM

Abstract  In this paper, I metatheoretically examine a design of normative sociology. Normative sociology is the normative-scientific study in sociology. The substance of normative science is the conceptual examination of values or value judgments. According to Coleman (1974) and Faran, (1989) et al., sociologists should contribute to normative science by using ideas from general sociological theory. There is a useful traditional enterprise for this aim in sociology; that is the study of the problem of order, particularly the study of it based on the rational choice paradigm. Seiyama (1992) points to the limits of the rational choice paradigm. I propose three aims of social theory, and claim that the study of the problem of order based on this paradigm is useful when our purpose is normative model-building. I call the problem of order as a subject of the study for this purpose "the value-theoretical problem of order." This examination can clear up some of the theoretical confusion surrounding the problem of order and show the methodological basis of normative sociology based on the rational choice paradigm.     

A Quantitative Theory of Unsecured Consumer Credit with Risk of Default

We study, theoretically and quantitatively, the general equilibrium of an economy in which households smooth consumption by means of both a riskless asset and unsecured loans with the option to default. The default option resembles a bankruptcy filing under Chapter 7 of the U.S. Bankruptcy Code. Competitive financial intermediaries offer a menu of loan sizes and interest rates wherein each loan makes zero profits. We prove the existence of a steady‐state equilibrium and characterize the circumstances under which a household defaults on its loans. We show that our model accounts for the main statistics regarding bankruptcy and unsecured credit while matching key macroeconomic aggregates, and the earnings and wealth distributions. We use this model to address the implications of a recent policy change that introduces a form of “means testing” for households contemplating a Chapter 7 bankruptcy filing. We find that this policy change yields large welfare gains.     

Aging, fertility, social security and political equilibrium

We analyze the effect of population aging on the political choice of the size of a pay-as-you-go (PAYG) social security system, incorporating the heterogeneity of individuals in their preference for having children, and hence the endogenous fertility choices of individuals, into a simple overlapping generations model. We show that population aging may result in an increase in the contribution rate, increasing the share of the retired population who prefer a higher contribution rate; and that, if the system involves redistribution between retirees with different contributions, the increased contribution rate raises the number of individuals who have children, i.e., future contributors.     

Fertility, child care outside the home, and pay-as-you-go social security

We examine the long-run effects of the pay-as-you-go (PAYG) social security scheme on fertility and welfare of individuals in an overlapping generations model, assuming that child-care services are available in the market. We show that the impact of a tax increase on fertility depends on the relative magnitudes of the standard intergenerational redistribution effect through the social security system, the (implicit) subsidy effect through tax-exemption of child rearing at home, and the price effect through changes in the relative price of market child care, and that if parental child-rearing time is inelastic, a tax cut could bring about a Pareto-improving allocation.

Spontaneous Facial Expressions Reveal New Action Units for the Sad Experiences

Facial expressions related to sadness are a universal signal of nonverbal communication. Although results of many psychology studies have shown that drooping of the lip corners, raising of the chin, and oblique eyebrow movements (a combination of inner brow raising and brow lowering) express sadness, no report has described a study elucidating facial expression characteristics under well-controlled circumstances with people actually experiencing the emotion of sadness itself. Therefore, spontaneous facial expressions associated with sadness remain unclear. We conducted this study to accumulate important findings related to spontaneous facial expressions of sadness. We recorded the spontaneous facial expressions of a group of participants as they experienced sadness during an emotion-elicitation task. This task required a participant to recall neutral and sad memories while listening to music. We subsequently conducted a detailed analysis of their sad and neutral expressions using the Facial Action Coding System. The prototypical facial expressions of sadness in earlier studies were not observed when people experienced sadness as an internal state under non-social circumstances. By contrast, they expressed tension around the mouth, which might function as a form of suppression. Furthermore, results show that parts of these facial actions are not only related to sad experiences but also to other emotional experiences such as disgust, fear, anger, and happiness. This study revealed the possibility that new facial expressions contribute to the experience of sadness as an internal state.     

Non-native plants are a seasonal pollen source for native honeybees in suburban ecosystems

In urban and suburban ecosystems, biodiversity can depend on various non-native plant species, including crop plants, garden plants and weeds. Non-native plants may help to maintain biodiversity by providing a source of forage for pollinators in these ecosystems. However, the contribution of plants in urban and agricultural areas to ecosystem services has often been underestimated in biodiversity assessments. In this study, we investigated the pollen sources of native honeybees (Apis cerana) in an arboretum containing native trees and urban and agricultural plants in a suburban landscape. We surveyed the flowering tree species planted inside the arboretum, which were potential pollen sources. The number of potential pollen-source species of native trees peaked in June and July and decreased after August. We collected A. cerana pollen balls every month and identified plant species of pollen in the collected pollen balls using DNA barcoding. In total, we identified 29 plant species from A. cerana pollen balls. The probability of A. cerana using pollen from urban and agricultural plants was higher in July and August than in June. A. cerana collected pollen forages from native tree species (53%), but also gathered pollen from crop plants (13%), garden trees (19%) and native and non-native weeds (14%); the predominant pollen sources in September and October were the garden tree Ulmus parvifolia and the non-native weed Solidago altissima. We found that native honeybees used plants from a variety of habitats including non-native plants to compensate for apparent seasonal shortages of native tree sources in suburban ecosystems. Our results highlight the importance of assessments of both positive and negative roles of non-native plants in urbanized ecosystems to improve biodiversity conservation.     

Non-expected utility maximizers behave as if expected utility maximizers: An experimental test

We investigate the behaviors of subjects who either do or do not adhere to the expected utility theory using the Becker–DeGroot–Marschak (BDM) method. We directly examine the validity of the expected utility theory in order to distinguish subjects into two groups: those who adhere to the expected utility theory (expected utility maximizers) and those who do not adhere to it (non-expected utility maximizers), and then execute the BDM experiment in the both groups. We find that the differences in the stated prices between the expected and non-expected utility maximizers are not significant. This result implies practical usefulness for the BDM method.     

A two-stage procedure for estimating a linear function of K multinormal mean vectors when covariance matrices are unknown

We consider the problem of constructing a fixed-size confidence region for a linear function of mean vectors of k multinormal populations, where all covariance matrices are completely unknown. A two-stage procedure is proposed to construct such a confidence region. It is shown that the proposed two-stage procedure is consistent and its asymptotic property for the expected sample size is also given. A Monte Carlo simulation study is given for an illustration.