On the Estimation Accuracy of Causal Effects using Supplementary Variables

This paper focuses on a situation in which a set of treatments is associated with a response through a set of supplementary variables in linear models as well as discrete models. Under the situation, we demonstrate that the causal effect can be estimated more accurately from the set of supplementary variables. In addition, we show that the set of supplementary variables can include selection variables and proxy variables as well. Furthermore, we propose selection criteria for supplementary variables based on the estimation accuracy of causal effects. From graph structures based on our results, we can judge certain situations under which the causal effect can be estimated more accurately by supplementary variables and reliably evaluate the causal effects from observed data.     

Family System Adjustment and Adaptive Reconstruction of Social Reality among the 1995 Earthquake Survivors

Abstract  The 1995 Great Hanshin-Awaji earthquake resulted in immense imbalances among and within natural ecosystems, the built environment, and human systems. The current study examined the relationship among familial adjustment, adaptive construction of social reality, and recovery of built environment. A random sample mail survey was conducted on 3,300 earthquake victims and 993 questionnaires were returned. The survey questionnaire included the following four scales that measured the family system adjustment on family cohesion and adaptability, the adaptive construction of new reality as evidenced by citizenship orientations, the current level of physical and psychological stress, and a subjective evaluation of life recovery. The results were as follows: (1) Those families that exhibited high cohesion and a clear leadership structure in the emergency period were more functional than others. (2) Those families that reported a balanced level of cohesion and adaptability during the recovery period were the most functional in promoting present individual recovery and in alleviating current stress. (3) The rise of civic-mindedness was observed among those who survived the disaster. (4) Those with high civic-mindedness tend to be better recovered with less current physical and psychological stress. This paper presented a human ecological model that described the relationships among five components: (1) the earthquake hazard, (2) built environment conditions such as disruption of the lifeline and its recovery, (3) opportunity costs for engaging in exchanges with either basic-trust-based ties or social-trust-based ties, (4) the optimal family system adjustment to corresponding exchange relations, and (5) adaptive construction of new social reality.     

The correlation between highly sensitive C-reactive protein levels and erectile function among men with late-onset hypogonadism

We investigated the correlation between highly sensitive C-reactive protein (hs-CRP) levels and erectile function, and assessed the clinical role of hs-CRP levels in men with late-onset hypogonadism (LOH) syndrome. For 77 participants, we assessed Sexual Health Inventory for men (SHIM) score, Aging Male Symptoms (AMS) score and International Prostate Symptom Score (IPSS). We also evaluated free testosterone (FT), hs-CRP, total cholesterol, triglyceride levels, high density lipoprotein cholesterol, hemoglobin A1c, body mass index, waist size and blood pressure. We attempted to identify parameters correlated with SHIM score and to determine the factors affecting cardiovascular risk based on hs-CRP levels. A Spearman rank correlation test revealed that age, AMS score, IPSS and hs-CRP levels were significantly correlated with SHIM score. Age-adjusted analysis revealed that hs-CRP and IPSS were the independent factors affecting SHIM score (r=??0.304 and ?0.322, respectively). Seventeen patients belonged to the moderate to high risk group for cardiovascular disease, whereas the remaining 60 belonged to the low risk group. Age, FT value and SHIM score showed significant differences between the two groups. A multivariate regression analysis demonstrated that SHIM score was an independent factor affecting cardiovascular risk (OR: 0.796; 95%CI: 0.637–0.995).     

A prospective longitudinal survey of erectile function status in symptomatic benign prostatic hyperplasia patients treated with dutasteride

We prospectively evaluated erectile function (EF) using the Sexual Health Inventory for Men (SHIM) and the erectile hardness score (EHS) as well as urinary statuses using the International Prostate Symptom Score (IPSS) and Overactive Bladder Symptom Score (OABSS) before and 3, 6, and 12 months after a daily treatment with 0.5?mg dutasteride (DUT). Significant improvements were observed in IPSS and OABSS in 98 patients with the DUT treatment, and the effects were similar between 28 patients with potency with baseline SHIM of 8 or greater and 70 severe erectile dysfunction (ED) patients at baseline. In the 28 patients with potency, significant decreases were observed in SHIM and EHS after 3, 6, and 12 months of the DUT treatment, with the severity of ED according to SHIM deteriorating in half of these patients after 12 months of the DUT treatment. Eighteen out of 28 patients (64.3%) with potency at baseline had awareness of the occurrence of ED before the DUT treatment, were younger, and had higher SHIM and EHS just before the DUT treatment than their counterparts. Regular assessments of EF may be needed, especially in younger patients and those with higher levels of EF before the administration of DUT.     

Bayesian analysis for mixtures of discrete distributions with a non-parametric component

Bayesian finite mixture modelling is a flexible parametric modelling approach for classification and density fitting. Many areas of application require distinguishing a signal from a noise component. In practice, it is often difficult to justify a specific distribution for the signal component; therefore, the signal distribution is usually further modelled via a mixture of distributions. However, modelling the signal as a mixture of distributions is computationally non-trivial due to the difficulties in justifying the exact number of components to be used and due to the label switching problem. This paper proposes the use of a non-parametric distribution to model the signal component. We consider the case of discrete data and show how this new methodology leads to more accurate parameter estimation and smaller false non-discovery rate. Moreover, it does not incur the label switching problem. We show an application of the method to data generated by ChIP-sequencing experiments.     

Does Japan Still Matter? Past Tendencies and Future Opportunities in the Study of Japanese Firms

This paper engages with the question ‘does Japan still matter’ by systematically reviewing publication patterns in peer‐reviewed academic journal articles addressing Japanese firms and their management practices, illustrating the academic discourse surrounding Japanese firms over four decades, and by identifying future research opportunities. Initially, particularly from the 1980s when Japanese firms came to prominence, these practices tended to be identified as ‘best practice’. However, at least in part due to socio‐economic changes, this tendency has become less prominent since the ‘bubble economy’ burst. Instead, three broader developments are observed: the examination of the continuity and change in the traditional Japanese model, a more complex approach that involves multiple themes of research, and leveraging new contexts to examine Japanese firms, including the long‐term recession, the rise of the East Asian economy, and the increasing importance of corporate social responsibility.     

General saddlepoint approximations to distributions under an elliptical population

General saddlepoint approximations are derived for the distributions of statistics under an elliptical population. The technique is applied to obtain the tail probabilities of latent roots of a sample covariance matrix. It is shown that the method based on normalizing transformations by Tsuchiya and Konishi (1997) is efficient for the sample correlation coefficient in an elliptical sample.     

Finite-sample analysis of impacts of unlabeled data and their labeling mechanisms in linear discriminant analysis

It is widely believed that unlabeled data are promising for improving prediction accuracy in classification problems. Although theoretical studies about when/how unlabeled data are beneficial exist, an actual prediction improvement has not been sufficiently investigated for a finite sample in a systematic manner. We investigate the impact of unlabeled data in linear discriminant analysis and compare the error rates of the classifiers estimated with/without unlabeled data. Our focus is a labeling mechanism that characterizes the probabilistic structure of occurrence of labeled cases. Results imply that an extremely small proportion of unlabeled data has a large effect on the analysis results.     

Relationship between collective efficacy and contextual performance among university athletes in Japan

The purpose of this study was to clarify the relationship between collective efficacy and contextual performance among university athletes in Japan. We carried out 305 university athletes (201 males, 104 females) from 14 teams in various geographic areas in Japan. The average age of the participants was 19.91 years (SD = 1.01). The kinds of sports were soccer, basketball, baseball, volleyball, and so on. Then, using Collective Efficacy Questionnaire for Sports (CEQS; Sandra E. Short et al., 2005) and Contextual Performance Scale (Ikeda, and Furukawa, 2008), we examined the relationship between collective efficacy and Contextual performance. In conclusion, this study provided the following three remarks. 1) There are relationship between collective efficacy and contextual performance. 2) Contextual performance execution level improve collective efficacy. 3) It is important to always recommend contextual performance in own team to strengthen the collective efficacy more.