Locally best invariant test for outliers in a gamma type distribution

It is shown that the locally best invariant test for the existence of outliers for scale parameters of the gamma distribution is given by Bartholomew's test for exponentiality which is the ratio of the sum of squares of the data to the square of the sample mean. The optimality robustness, including null and nonnull robustness of the test is shown. A small simulation study to compare the power among the other eight competitive tests for testing exponentiality is performed. It is seen that the locally best invariant test is not always best but is reasonably good. It is slightly better than Cochran's test and suffers less from the limiting masking effect.     

Kernel naive Bayes discrimination for high‐dimensional pattern recognition

Kernel discriminant analysis translates the original classification problem into feature space and solves the problem with dimension and sample size interchanged. In high‐dimension low sample size (HDLSS) settings, this reduces the ‘dimension’ to that of the sample size. For HDLSS two‐class problems we modify Mika's kernel Fisher discriminant function which – in general – remains ill‐posed even in a kernel setting; see Mika et al. (1999). We propose a kernel naive Bayes discriminant function and its smoothed version, using first‐ and second‐degree polynomial kernels. For fixed sample size and increasing dimension, we present asymptotic expressions for the kernel discriminant functions, discriminant directions and for the error probability of our kernel discriminant functions. The theoretical calculations are complemented by simulations which show the convergence of the estimators to the population quantities as the dimension grows. We illustrate the performance of the new discriminant rules, which are easy to implement, on real HDLSS data. For such data, our results clearly demonstrate the superior performance of the new discriminant rules, and especially their smoothed versions, over Mika's kernel Fisher version, and typically also over the commonly used naive Bayes discriminant rule.     

Influence of a home-based exercise program on the urine pH in elderly female subjects: a secondary analysis of a randomized controlled trial

Background

A low urine pH is a characteristic metabolic feature of metabolic syndrome and type 2 diabetes. The purpose of the current study was to investigate the effects of a 12-week home-based bench step exercise on the urine pH status of elderly female subjects.

Methods

The current study is a secondary analysis of a randomized controlled trial (RCT) in which 59 postmenopausal female subjects were randomized to either the exercise group (n?=?29) or the control group (n?=?30). The subjects in the exercise group were instructed to perform home-based exercises using a bench step at the anaerobic threshold (AT), with a goal of performing ≥140 min/week at home for 12 weeks. The subjects in the control group were instructed to not change their normal lifestyle. Urine was collected after overnight fasting, and the urine pH was measured using a urinary test strip. The inter-group-differences at baseline and the pre-post changes within groups were assessed using the Mann-Whitney U test and Wilcoxon’s signed-rank test, respectively. Additionally, the difference in the post-intervention urine pH levels of the two groups, adjusted for the pre-intervention values (the estimated effect size) and the precision (95% confidence intervals) were investigated using an analysis of covariance.

Results

The pre-post comparison of the urine pH data using Wilcoxon’s signed-rank test showed a significant increase in the urine pH levels of the exercise group (p?<?0.05); there was no significant change in the urine pH levels of the control group. However, the estimated effect size (0.15) was small and the confidence interval straddled 0 (?0.25–0.55).

Conclusions

Based on the results of the current secondary analysis of an RCT, we could not clearly conclude that exercise has a beneficial effect on the urine pH. Further well-designed RCTs should be conducted to determine whether aerobic exercise is truly able to ameliorate urine acidification.

Trial registration

The study was retrospectively registered in the University Hospital Medical Information Network (UMIN) as “Effect of step exercise on aerobic fitness and progression of atherosclerosis in the elderly” under the registration number UMIN 000026743 (the date of registration: March 28, 2017).

     

Finite Sample Modifications of the Granger Non Causality Test in Cointegrated Vector Autoregressions

This article deals with the Granger non causality test in cointegrated vector autoregressive processes. We propose a new testing procedure that yields an asymptotically standard distribution and performs well in small samples by combining the standard Wald test and the generalized inverse procedure. We also propose a few simple modifications to the test statistics in order to help our procedure perform better in finite samples. Monte Carlo simulations show that our procedure works better than the conventional approach.     

On Labor Policies Affecting Investment in General Human Capital

Abstract. This paper develops a search model including workers’ investments in general human capital and investigates the effects of labor policies such as subsidies to human capital investment and unemployment benefits on the accumulation of human capital. It is shown that the equilibrium is not optimal because workers underinvest in human capital or firms open too many vacancies in comparison with the number of unemployed workers. Comparative statics show that an increase in subsidies to human capital investment adds to the number of vacancies per unemployed worker and to workers’ investments in human capital and that an increase in unemployment benefits decreases them. Finally, labor policies that remove the distortion are explored.     

Comparative studies on the seasonal occurrence, nymphal development and food menu in two giant water bugs,Diplonychus japonicus vuillefroy andDiplonychus major esaki (Hemiptera: Belostomatidae)

Summary We compared the seasonal changes in population density and nymphal development at different water temperatures and under different food conditions between two giant water bugs,Diplonychus japonicus andD. major, in Okayama, Japan. D. japonicus produced 1–2 generations a year, whileD. major was strictly inivoltine. The developmental velocity was higher inD. japonicus than inD. major. The thermal constant ofD. japonicus was less than that ofD. major. These results suggest thatD. japonicus is adapted, to higher water temperature thanD. major. In the field,D. japonicus preyed predominately on Lymnaeidae and Physidae snails, whileD. major preyed on aquatic insects such as dragonfly nymphs.     

Lesbian discourses in mainstream magazines of post-war Japan: is onabe distinct from rezubian?

This paper elucidates the changes in the meanings associated with the term rezubian (the Japanese term for "lesbian") through an analysis of its discourse in magazines for general readership published in post-war Japan. The category of "rezubian" first appeared in mainstream magazines in the 1960s as a generic category that referred to both "masculinized women" and "women who engage in sexual acts with other women." Masculinized women, in particular, were called "onabe." At first "onabe" denoted "a tachi rezubian," meaning a lesbian who plays "top," but gradually a distinction came to be made between "rezubian who are onabe" and "rezubian who aren't." The early 1990s saw the differentiation of "onabe" as a category distinct from that of "rezubian." Focusing particularly on this process of differentiation, this paper traces the transitions in the signifying practices pertaining to the category rezubian. doi:10.1300/J155v10n03_09.     

Improved estimators for the location of double exponential distribution

In this paper, attention is focused on estimation of the location parameter in the double exponential case using a weighted linear combination of the sample median and pairs of order statistics, with symmetric distance to both sides from the sample median. Minimizing with respect to weights and distances we get smaller asymptotic variance in the second order. If the number of pairs is taken as infinite and the distances as null we attain the least asymptotic variance in this class of estimators. The Pitman estimator is also noted. Similarly improved estimators are scanned over their probability of concentration to investigate its bound. Numerical comparison of the estimators is shown.