Inequality for equireplicated n-ary block designs with unequal block sizes

It is shown that certain inequalities known for binary, equireplicated, equiblock-sized block designs remain valid for equireplicated n-ary block designs with unequal block sizes. The approach used here is based on the spectral expansion of the C-matrix of the block design. The main theorems include some useful and combinatorially interesting results.     

Alzheimer's disease,neuropeptides, neuropeptidase,and amyloid-beta peptide metabolism

Amyloid-beta peptide (Abeta), the pathogenic agent of Alzheimer's disease (AD), is a physiological metabolite in the brain. We have focused our attention and effort on elucidating the unresolved aspect of Abeta metabolism: proteolytic degradation. Among a number of Abeta-degrading enzyme candidates, we used a novel in vivo paradigm to identify a member of the neutral endopeptidase family, neprilysin, as the major Abeta catabolic enzyme. Neprilysin deficiency results in defects in the metabolism of endogenous Abeta 40 and 42 in a gene dose-dependent manner. Our observations suggest that even partial down-regulation of neprilysin activity, which could be caused by aging, can contribute to AD development by promoting Abeta accumulation. Moreover, we discuss the fact that an aging-dependent decline of neprilysin activity, which leads to elevation of Abeta concentrations in the brain, is a natural process that precedes AD pathology. In this Perspective, we hypothesize that neprilysin down-regulation has a role in sporadic AD (SAD) pathogenesis, and we propose that this knowledge be used for developing preventive and therapeutic strategies through use of a G protein-coupled receptor (GPCR).     

The effects on the distributions of sample canonical correlations under nonnormality

In this paper, we study the effects of nonnormality on the distributions of sample canonical correlations when the population canonical correlations are simple. In order to achieve the purpose, we derive asymptotic expansion formulas for the distributions of a function of the canonical correlations as well as the individual canonical correlations under nonnormal populations. We particularly discuss the distribution of sample canonical correlations under the class of elliptical population. These expansions are given by using a perturbation method. Simulation results are also given.     

Relative Curvature Measure for Heteroscedastic or Non Normal Nonlinear Regression

The Bates–Watts relative curvature measure can assess the validity of the linearized approximation in nonlinear regression models. However, it is developed based on an ordinary nonlinear regression in which the observation is assumed to be homoscedastically and normally distributed. In this article, we extend the original Bates–Watts relative curvature measure to one that can be applicable to nonlinear regression with heteroscedastic or non normal data, based on the transformation-both-sides (TBS) approach. In pharmacokinetic models, a diagnostic use of their measures is illustrated. By means of a simulation experiment, the performance of the relative curvature measure for the TBS approach is evaluated.     

Estimation of the covariance matrix with two-step monotone missing data

Abstract

We suggest shrinkage based technique for estimating covariance matrix in the high-dimensional normal model with missing data. Our approach is based on the monotone missing scheme assumption, meaning that missing values patterns occur completely at random. Our asymptotic framework allows the dimensionality p grow to infinity together with the sample size, N, and extends the methodology of Ledoit and Wolf (2004) Ledoit, O., Wolf, M. (2004). A well-conditioned estimator for large dimensional covariance matrices. J. Multivariate Anal. 88:365–411.[Crossref], [Web of Science ®] , [Google Scholar] to the case of two-step monotone missing data. Two new shrinkage-type estimators are derived and their dominance properties over the Ledoit and Wolf (2004) Ledoit, O., Wolf, M. (2004). A well-conditioned estimator for large dimensional covariance matrices. J. Multivariate Anal. 88:365–411.[Crossref], [Web of Science ®] , [Google Scholar] estimator are shown under the expected quadratic loss. We perform a simulation study and conclude that the proposed estimators are successful for a range of missing data scenarios.     

Bayesian sample‐size determination methods considering both worthwhileness and unpromisingness for exploratory two‐arm randomized clinical trials with binary endpoints

A randomized exploratory clinical trial comparing an experimental treatment with a control treatment on a binary endpoint is often conducted to make a go or no‐go decision. Such an exploratory trial needs to have an adequate sample size such that it will provide convincing evidence that the experimental treatment is either worthwhile or unpromising relative to the control treatment. In this paper, we propose three new sample‐size determination methods for an exploratory trial, which utilize the posterior probabilities calculated from predefined efficacy and inefficacy criteria leading to a declaration of the worthwhileness or unpromisingness of the experimental treatment. Simulation studies, including numerical investigation, showed that all three methods could declare the experimental treatment as worthwhile or unpromising with a high probability when the true response probability of the experimental treatment group is higher or lower, respectively, than that of the control treatment group.     

Teaching Perspectives on Cross-Cultural Psychology and Japanese Society

This article discusses educational aspects of cross-cultural psychology in relationship to Japanese society. After exploring the present status of cross-cultural psychology in Japan, the paper delineates the factual, theoretical, and methodological implications of cross-cultural psychology for the teaching of psychology in Japanese universities. It is argued that an area approach incorporating comparative research on Japanese society can add context, detail, historical perspective, new methodology, and interdisciplinary richness to classes otherwise relying on traditional journal articles and textbooks of cross-cultural psychology. Such an approach is deemed useful for cross-cultural psychology classes taking place both inside and outside Japan. The article concludes with an annotated bibliography of research on Japanese society.     

Social Workers' Use of the Internet and E-Mail to Help Clients in Virginia

A survey of a random sample of licensed social workers in Virginia showed 98.8% had Internet access in either their home or workplace. A comparison of this study with a study conducted in the early 2000s indicated more than 20% difference regarding e-mail communication with clients and Internet use for work-related research. Social workers who actually used the Internet and e-mail tended to expect a future increase in their use, in contrast with nonusers. Stepwise multiple logistic regression analyses found age and type of agency (private/for-profit) as factors negatively related to having Internet access in the workplace, age, and the reason “E-mail is not secure enough” as factors negatively related in the future e-mail communication with clients among current nonusers.