Latent mixture modeling for clustered data

Statistics and Computing - This article proposes a mixture modeling approach to estimating cluster-wise conditional distributions in clustered (grouped) data. We adapt the mixture-of-experts model...     

新农村建设中少数民族地方行政组织的改革及其问题

进行社会主义新农村建设,应注意农村综合改革中地方行政组织的改革,而在少数民族地区进行地方行政组织的改革更是一个艰巨任务。在采取社会学的文献调查、实地调查和向地方政府问卷调查等方法基础上,在阐明中国农村行政体制改革的内容及其存在问题的同时,着重分析内蒙古少数民族农村牧区基层行政组织改革的目标和任务。     

Bayesian response adaptive randomization using longitudinal outcomes

The response adaptive randomization (RAR) method is used to increase the number of patients assigned to more efficacious treatment arms in clinical trials. In many trials evaluating longitudinal patient outcomes, RAR methods based only on the final measurement may not benefit significantly from RAR because of its delayed initiation. We propose a Bayesian RAR method to improve RAR performance by accounting for longitudinal patient outcomes (longitudinal RAR). We use a Bayesian linear mixed effects model to analyze longitudinal continuous patient outcomes for calculating a patient allocation probability. In addition, we aim to mitigate the loss of statistical power because of large patient allocation imbalances by embedding adjusters into the patient allocation probability calculation. Using extensive simulation we compared the operating characteristics of our proposed longitudinal RAR method with those of the RAR method based only on the final measurement and with an equal randomization method. Simulation results showed that our proposed longitudinal RAR method assigned more patients to the presumably superior treatment arm compared with the other two methods. In addition, the embedded adjuster effectively worked to prevent extreme patient allocation imbalances. However, our proposed method may not function adequately when the treatment effect difference is moderate or less, and still needs to be modified to deal with unexpectedly large departures from the presumed longitudinal data model. Copyright © 2015 John Wiley & Sons, Ltd.     

Implications of urbanism for the use of local news media: effects of population concentration on types of news acquisition in Japan

The Internet, a global computer network enabling people to send and receive information anywhere in the world, also functions as a local medium of communication. This study focuses on the role of the Internet in transmitting local news and examines the effects of community population concentrations as socio-ecological environments on the use of local news media consumed online and offline. Data from 1367 respondents across 156 Japanese communities were used to analyze the relationships between type of community and type of news source. The findings suggest that people who live in highly populated communities tend more often to use the Internet to access local news, whereas those in less populated communities tend to use more traditional mass media. However, the results of this study did not show a relationship between population concentrations within communities and the acquisition of international news, nor did the social features of residents adequately explain the effects of population concentration on the acquisition of local news. These results are consistent with theoretical predictions based on network externalities, urbanism, and collective action. The findings indicate that local news consumption is embedded in local social contexts in a way that international news is not, reinforcing the importance of urbanism in the information age.     

Replacement policies for age and working numbers with random life cycle

It has been modeled for several replacement policies in literatures that the whole life cycle or operating interval of an operating unit should be finite rather than infinite as is done with the traditional method. However, it is more natural to consider the case in which the finite life cycle is a fluctuated parameter that could be used to estimate replacement times, which will be taken up in this article. For this, we first formulate a general model in which the unit is replaced at random age U, random time Y for the first working number, random life cycle S, or at failure X, whichever occurs first. The following models included in the general model, such that replacement done at age T when variable U is a degenerate distribution, and replacement done at working numbers N summed by number N of variable Y, are optimized. We obtain the total expected cost until replacement and the expected replacement cost rate for each model. Optimal age T, working number N, and a pair of (T, N) are discussed analytically and computed numerically.     

Species diversity preserved in different numbers of nature reserves of the same total area

Conclusion and Summary The expected number of species occurring in different numbers of reserves of the same total area is examined on different assumptions of the spatial distribution and the probability of extinction. The advantage of one large reserve or several smaller ones of equal total area depends on the spatial distributions of species and the stage after the establishement of reserves. In general, several smaller reserves maintain more species immediately after the establishments unless the spatial distribution are uniform or random, whereas one large reserve excels several smaller ones after some rare species have gone extinct unless the spatial distributions are strongly contagious. Since the extinction of rare species must be facilitated as the size of each reserve reduces, the area of a reserve should be larger than the critical area that ensures the persistence of the species. Hence it is concluded that one or a few large reserves are a better strategy in order to maintain the species diversity.     

The controversial promises of cholinesterase inhibitors for Alzheimer's disease and related dementias: A qualitative study of caregivers' experiences

Since their introduction, clinicians have been engaging in debates over the therapeutic benefits of cholinesterase inhibitors (ChEIs) in Alzheimer's disease and related dementias (ADRD). Against this backdrop of controversy, caregivers' views and experiences have been largely ignored. This has occurred despite the fact that this group may provide insights into these drugs in ways not captured by clinical research. To address this gap in knowledge, the current study examines 25 caregivers' narratives about the treatment of relatives diagnosed with mild to moderate ADRD and treated with ChEIs. The findings reveal an appraisal of cholinergic effects whereby caregivers question the benefits of the drugs, generally not knowing whether to attribute stabilization or improvements to them or not but also fearing termination of the drug ‘just in case’ there is some benefit. Caregivers justify their belief in ChEIs' long-term effectiveness primarily by invoking non-medicated prognostic scenarios of more rapid decline and loss of self. In addition, the study explores the meaning caregivers attribute to ChEI effects vis-à-vis a pharmaceutical discourse which frames these drugs as a source of hope.     

The evaluation of general non-centred orthant probabilities

Summary. The evaluation of the cumulative distribution function of a multivariate normal distribution is considered. The multivariate normal distribution can have any positive definite correlation matrix and any mean vector. The approach taken has two stages. In the first stage, it is shown how non-centred orthoscheme probabilities can be evaluated by using a recursive integration method. In the second stage, some ideas of Schläfli and Abrahamson are extended to show that any non-centred orthant probability can be expressed as differences between at most ( m −1)! non-centred orthoscheme probabilities. This approach allows an accurate evaluation of many multivariate normal probabilities which have important applications in statistical practice.     

Division of Household Labor and Marital Satisfaction in China, Japan, and Korea

In this study, we compared the association of marital satisfaction with the division of household labor in China, Japan, and Korea. Results revealed that wives’ marital satisfaction was negatively associated with their burden of housework in the three Asian countries, as generally observed in Western countries. However, there were noticeable cross-country differences. Chinese couples were relatively in favor of an egalitarian division of household labor. Japanese couples were supportive of traditional specialization, with wives flexibly shifting their efforts between work outside the house and housework. Korean couples were under pressure from conflicts between the wife’s labor force participation and the traditional division of labor. These findings underscored the importance of the socio-institutional context in the study of marital satisfaction.