A modified likelihood ratio test for the mean direction in the von mises distribution

The likelihood ratio test (LRT) for the mean direction in the von Mises distribution is modified for possessing a common asymptotic distribution both for large sample size and for large concentration parameter. The test statistic of the modified LRT is compared with the F distribution but not with the chi-square distribution usually employed, Good performances of the modified LRT are shown by analytical studies and Monte Carlo simulation studies, A notable advantage of the test is that it takes part in the unified likelihood inference procedures including both the marginal MLE and the marginal LRT for the concentration parameter.     

Moment estimators for the beta-binomial distribution

A new moment estimator of the dispersion parameter of the beta-binomial distribution is proposed. It is derived by the method of moments which is constrained to satisfy the unbiasedness of the estimating equation. It gives a better performance than those of the usual moment estimators and the stabilized moment estimator proposed by Tamura & Young. The bias of the estimator is smaller than that of the maximum likelihood estimate in a wide range of parameter space.     

On the Usefulness or Lack Thereof of Optimality Criteria for Structural Change Tests

Elliott and Müller (2006) considered the problem of testing for general types of parameter variations, including infrequent breaks. They developed a framework that yields optimal tests, in the sense that they nearly attain some local Gaussian power envelop. The main ingredient in their setup is that the variance of the process generating the changes in the parameters must go to zero at a fast rate. They recommended the so-called qL?L test, a partial sums type test based on the residuals obtained from the restricted model. We show that for breaks that are very small, its power is indeed higher than other tests, including the popular sup-Wald (SW) test. However, the differences are very minor. When the magnitude of change is moderate to large, the power of the test is very low in the context of a regression with lagged dependent variables or when a correction is applied to account for serial correlation in the errors. In many cases, the power goes to zero as the magnitude of change increases. The power of the SW test does not show this non-monotonicity and its power is far superior to the qL?L test when the break is not very small. We claim that the optimality of the qL?L test does not come from the properties of the test statistics but the criterion adopted, which is not useful to analyze structural change tests. Instead, we use fixed-break size asymptotic approximations to assess the relative efficiency or power of the two tests. When doing so, it is shown that the SW test indeed dominates the qL?L test and, in many cases, the latter has zero relative asymptotic efficiency.     

Quantitative analyses of misclassification rates in the hazard classification of environmental chemicals: Evaluation of procedures for deriving predicted no-effect concentrations in the Chemical Substance Control Law in Japan

The quality of chemical management depends more or less on practical procedures used to assess chemicals. This study quantitatively assessed the efficacy of a derivation procedure for calculating no-effect concentrations for screening assessment of environmental hazards under the Chemical Substance Control Law in Japan. We first evaluated the derivation procedure by applying a series of test ecotoxicity datasets to the procedure and calculating the resulting misclassification rates of the hazardous class of chemicals. In this study, a chemical was deemed to have been misclassified if its classification differed from its classification based on the full dataset (chronic toxicity data for three trophic levels), which was defined as the correct assignment. We also calculated the effects of additional uncertainty factors to decrease the variance (i.e., to improve the consistency) of the misclassification rates among cases with different data availability in the derivation procedure. The results showed that the derivation procedure resulted in very high rates of misclassification when only particular sets of ecotoxicity data were available (e.g., only chronic toxicity data of algae were available). Our analyses also showed that the use of additional uncertainty factors improved the consistency of the misclassification rates within the derivation procedure. Our study presents a broadly applicable calculation framework for quantifying error rates in assessment procedures and serves as a case study for future development and reforms of chemical assessment processes and policies, while additional analyses using more extensive ecotoxicity data with various modes of actions are needed in the future.     

Salvage therapy trial for erectile dysfunction using phosphodiesterase type 5 inhibitors and vitamin E: Preliminary report

We report our initial experience with salvage therapy for low responders to PDE-5 inhibitors by adding vitamin E. Of 89 patients with ED who visited our clinic between January 2004 to August 2006, 9 were unable to obtain a full response to a PDE-5 inhibitor and included in the present study. After providing informed consent, each was given 300 mg per day of α-tocophenol at least 1 month and completed IIEF-5 questionnaires to assess its efficacy while also taking a PDE-5 inhibitor. With α-tocophenol administration, the average IIEF-5 score increased from 13.8 ± 3.2 to 17.1 ± 3.6. Four of seven patients who completed the questionnaire each time showed improved IIEF-5 scores, with a maximum elevation of 9 points. Further, eight of the nine patients experienced favourable subjective changes, the majority being increased penile rigidity. The present clinical trial results are, to our knowledge, the first known to show the effects of vitamin E for enhancing the efficacy of a PDE-5 inhibitor.     

Repeated Games Where the Payoffs and Monitoring Structure Are Unknown

This paper studies repeated games with imperfect public monitoring where the players are uncertain both about the payoff functions and about the relationship between the distribution of signals and the actions played. We introduce the concept of perfect public ex post equilibrium (PPXE), and show that it can be characterized with an extension of the techniques used to study perfect public equilibria. We develop identifiability conditions that are sufficient for a folk theorem; these conditions imply that there are PPXE in which the payoffs are approximately the same as if the monitoring structure and payoff functions were known. Finally, we define perfect type‐contingently public ex post equilibria (PTXE), which allows players to condition their actions on their initial private information, and we provide its linear programming characterization.     

Swaying in time and space: the Chinese Diaspora in the Caribbean and its literary perspectives

Despite that the Chinese in the Caribbean, unlike Africans or East Indians, is vaguely impressive in terms of racial and social impact; their stance and viewpoint are quite unique and insightful. Willi Chen and Jan Lowe Shinebourne, representing Chinese Caribbean Diaspora, are impressive enough with its strong literary impact. They both show the ambivalence acquired in the process of ‘positioning’, as well as the strong heritage of their ancestral mother land of China. Chen’s work is characteristic with its neutral stance of Chinese characters, and Shinebourne makes her protagonists wander with intermingling sense of tradition and progression. This ambivalence, however, can become a positive sway between groups which may be different, conflictive, or even hostile to each other, and that sway can bring a righteous and truthful judgment to the matter. The Chinese Caribbean writings contribute with the dialectic philosophies included in and inherited from Chinese traditions.     

The Effects of Social Interaction and Personal Relationships on Facial Expressions

Previous studies have reported that the expression of smiles is facilitated by social interaction between partners. We examined the effects of social interaction and personal relationships on facial expressions in Japan. Pairs of friends and strangers seated next to each other (the no partition condition) or separated by a partition (the partition condition) were shown film clips aimed to elicit either positive or negative affect. Smiles were facilitated in the no partition condition in which participants interacted with each other. Further, the effect of social interaction on frowns differed depending on whether pairs were friends or strangers.     

Crossing Boundaries: Legality and the Power of the State in Unauthorized Migration

Unauthorized migrants, often referred to as 'illegal aliens' or 'undocumented immigrants', are a burning political issue in many countries. This paper examines the complexities of unauthorized migration and addresses competing viewpoints on the subject as it relates to the power of the state. Despite the popular image of unauthorized migration as secret border crossing, migrants become 'illegal' in various ways, and the boundary between 'legal' and 'illegal' is more fluid than it may appear to be. Unauthorized migration is conventionally understood as evidence of the limited power of the state over immigration. This view, however, too narrowly focuses on the power of the state over entries of migrants. If we broaden our perspective and examine its power over migrants' lives and the way in which they are integrated into society, unauthorized migration in fact reveals the strong power of the state, which has a capacity to deprive migrants of their rights.