Evaluation of Gaussian orthant probabilities based on orthogonal projections to subspaces

In this paper, a new procedure is described for evaluating the probability that all elements of a normally distributed vector are non-negative, which is called the non-centered orthant probability. This probability is defined by a multivariate integral of the density function. The definition is simple, and this probability arises frequently in statistics because the normal distribution is prevalent. The method for evaluating this probability, however, is not obvious, because applying direct numerical integration is not practical except in low dimensional cases. In the procedure proposed in this paper, the problem is decomposed into sub-problems of lower dimension. Considering the projection onto subspaces, the solutions of the sub-problems can be shared in the evaluation of higher dimensional problems. Thus the sub-problems form a lattice structure. This reduces the computational time from a factorial order, where the interim results are not shared, to order \(p^{2}2^{p}\), which is faster than the procedures that have been reported in the literature.     

Japanese Children’s Knowledge of the Facial Components of Basic Emotions

While numerous studies have investigated children’s recognition of facial emotional expressions, little evidence has been gathered concerning their explicit knowledge of the components included in such expressions. Thus, we investigated children’s knowledge of the facial components involved in the expressions of happiness, sadness, anger, and surprise. Four- and 5-year-old Japanese children were presented with the blank face of a young character, and asked to select facial components in order to depict the emotions he felt. Children’s overall performance in the task increased as a function of age, and was above chance level for each emotion in both age groups. Children were likely to select the Cheek raiser and Lip corner puller to depict happiness, the Inner brow raiser, Brow lowerer, and Lid droop to depict sadness, the Brow lowerer and Upper lid raiser to depict anger, and the Upper lid raiser and Jaw drop to depict surprise. Furthermore, older children demonstrated a better knowledge of the involvement of the Upper lid raiser in surprise expressions.     

Multiple comparisons in two-factor testing of psychophysical thresholds by the delta test method

We propose an algorithm of multiple comparisons in two-factor testing of psychophysical thresholds. We use logistic regression combined with guessing rate and adopt the step-down procedure with Ryan–Einot–Gabriel–Welsch (REGW) significance levels for multiple test. We test hypotheses of main effects and interaction in two-factor problem by using the delta test statistics.     

Adaptation and validation of the Japanese version of the Gambling Urge Scale

In Japan, accurately assessing and targeting gambling urges is important for the treatment of gambling disorder because people are constantly exposed to external triggers that elicit gambling urges. However, a valid measure that assesses gambling urges has not been adequately established. Therefore, the purpose of this study was to examine the psychometric properties of the Japanese version of the Gambling Urge Scale (GUS-J), which is a well-known valid 6-item instrument in English-speaking countries. Two hundred and thirty-nine participants completed questionnaires, 86 of which met the criteria for a probable gambling disorder. As with the original GUS, the GUS-J was demonstrated to be a one-factor model that accounted for 63.82% of the total item variance, with all items demonstrating loadings of .40 or higher. With regard to reliability, the GUS-J showed good internal consistency (α = .88). Furthermore, validity based on evidence of relationships with other variables, especially convergent and concurrent validity of the GUS-J, were supported by several analyses that examined hypotheses based on previous findings. In conclusion, this study showed that the GUS-J has good psychometric properties as an assessment tool for gambling urges in Japanese people and it will be useful for future clinical practice and research.     

On the almost unbiased ridge regression estimator

The purpose of this paper is two-fold. One is to compare the almost unbiased generalized ridge regression (AUGRR) estimator proposed by Singh, Chaubey and Dwivedi (1986) with the generalized ridge regression (GRR) estimator and with the ordinary least squares (OLS) estimator in terms of the mean squared error criterion. Second is to examine small sample properties of the operational almost unbiased ordinary ridge regression (AUORR) estimator by Monte Carlo experiments.     

Optimal clutch size of the chestnut gall-wasp,Dryocosmus kuriphilus yasumatsu (Hymenoptera: Cynipidae)

Summary Optimal clutch size of the chestnut gall-wasp,Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), was examined in galls on wild and resistant chestnut trees in 1988 and 1989. The rate of escape success of newly-emerged adults from galls was an average of 60%, irrespective of cell numbers per gall. Dry mass per cell of a gall (as an index of nutritive condition) decreased with increasing cell number per gall, but was proportional to the mean number of mature eggs of new adults per gall. The number of cells per gall that occurred most frequently did not agree with that attained by the maximum survival rate from young larva to adult emergence of the gall-wasp. This discrepancy was examined from the viewpoint of three factors: 1) quality of offspring, 2) defensive response of the host plant causing mortality of the gall-wasp before cell formation, and 3) fitness per gall vs. fitness per egg. It is concluded that the third factor is most likely to be the one best in explaining the discrepancy.     

Increasing flexibility in shiftwork arrangements

Abstract

Renewed interest in increasing flexibility in working time arrangements derives from both social and economic changes. The dominant reasons for greater flexibility in shiftwork arrangements relate to diverse business demands resulting from competitive pressures and rapid technological change, modern workers' personal preferences about the timing of work, and the reduction in hours of work. Many new patterns are applied to meet these demands. A review of innovative patterns reveals their close link with shorter working hours and diversifying career needs. Typical patterns include (a) hours averaging schemes, (b) flexible daily hours, (c) individualized free time schemes. (d) flexitime plus shift systems, (e) a combination of full-time and part-time systems, (f) job sharing, (g) temporary transfer to day work, and (h) career break schemes. Attention is drawn to multi-skilling of workers associated with more independent responsibility and closer communication. Changes to a flexible pattern are usually a result of consultations that respond to the conflicting interests of employers and workers. Support is necessary for a process of informed joint planning. Particularly useful are: (1) identification of operational demands and individual preferences about increasing flexibility in work schedules; (2) presentation of available options with information on implications for workers' health and social life; and (3) facilitating training and group consultation. The adjustments required depend greatly on how the tasks of individual workers are reorganized. In increasing the flexibility of shift schedules, it is important to learn from positive experiences of joint optimization of work content and working time arrangements.     

A note on combining ridge and principal component regression

Baye and Parker (1984) proposed the r-k class estimator. The purpose of this note is to deal with the comparisons among the r-k class estimators in terms of the mean square error criterion.     

Trends in the participatory process of changing shiftwork arrangements

Abstract

A recent survey by the International Labour Office on changing shiftwork arrangements showed that there were three essential steps commonly taken in the change process in different countries. They could be identified as: (1) group study of operational requirements and workers' needs; (2) establishing feasible options; and (3) consensus building while acting on conflicting interests. The change process was more successful when it was provided with concrete support. Attention is drawn to three major aspects of such support: (a) gathering data about operational requirements of the enterprise and workers' needs and preferences (by applying practical methods such as questionnaire surveys, interviews, group discussion and workshops); (b) support for the participatory development of plans for new arrangements (by organizing a group involving workers' representatives); and (c) training support for facilitating the group work and bargaining required for consensus building. Locally adapted training support is necessary particularly about: (1) understanding shiftwork effects and generally accepted guidelines; (2) how to find feasible options based on gathered data and these guidelines; and (3) how to cope with shiftwork. Thus support from people experienced in facilitating the well-informed, participatory process of change will need to be developed for promoting the improvement of shiftworking conditions.     

Estimation of the average causal effect via multiple propensity score stratification

Suppose we are interested in estimating the average causal effect (ACE) for the population mean from observational study. Because of simplicity and ease of interpretation, stratification by a propensity score (PS) is widely used to adjust for influence of confounding factors in estimation of the ACE. Appropriateness of the estimation by the PS stratification relies on correct specification of the PS. We propose an estimator based on stratification with multiple PS models by clustering techniques instead of model selection. If one of them correctly specifies, the proposed estimator removes bias and thus is more robust than the standard PS stratification.