Grandparent caregiving and cognitive functioning among older people: evidence from Korea

Review of Economics of the Household - Caregiving for grandchildren is becoming common and plays an important role in the childcare system in many countries. This study examines whether caregiving...     

On the block lu decomposition of block toeplitz matrices using the vector yule-walker equations

It is shown that the inverse of a block Toeplitz matrix can be factored into a product of an upper block triangular, a block diagonal and a lower block triangular matrices, where the component matrices consist of the solutions of the forward and backward extended Yule-Walker equations. Also, a recursive algorithm is presented to decompose nested Toeplitz matrices, which is a generalization of the Levinson-Durbin algorithm. Its derivation is elementary. The decomposition and the algorithm are useful for solving a block Toeplitz system of simultaneous equations, particularly, which appears in the vector autoregressive moving-average model analysis.     

Variable Selection for Naive Bayes Semisupervised Learning

This article deals with a semisupervised learning based on naive Bayes assumption. A univariate Gaussian mixture density is used for continuous input variables whereas a histogram type density is adopted for discrete input variables. The EM algorithm is used for the computation of maximum likelihood estimators of parameters in the model when we fix the number of mixing components for each continuous input variable. We carry out a model selection for choosing a parsimonious model among various fitted models based on an information criterion. A common density method is proposed for the selection of significant input variables. Simulated and real datasets are used to illustrate the performance of the proposed method.     

A parametric approach for measuring the effect of the 10th revision of the international classification of diseases

Summary.  The World Health Organization revises the international classification of diseases about every 10 years to stay abreast of advances in medical science and to compare international health statistics. However, the new revision (i.e. the 10th revision) introduces discontinuities in mortality trends, making it impossible to compare the mortality statistics before and after the revision directly. The US National Center for Health Statistics published comparability ratios to correct the discontinuities between the two sets of mortality data: one coded by the ninth revision and the other by the 10th revision. We propose a parametric two-stage model to produce new comparability ratios and use these ratios to correct the discontinuities. The asymptotic behaviour of the comparability ratios is investigated. Our model not only measures the extent of discontinuities in trends in mortality but also can be used to forecast future mortality. Comparing with the National Center for Health Statistics's ratios, our comparability ratios smooth out the discontinuities better for most causes.     

Neighborhoods, Family, and Substance Use: Comparisons of the Relations across Racial and Ethnic Groups

This study examines how substance use among adolescents is related to several risk and protective factors derived from two ecological contexts: the neighborhood and the family. It explicitly investigates how the relationships between substance use and the factors vary across different racial and ethnic groups. Findings suggest many common correlates and processes of substance use for adolescents, regardless of race or ethnicity, including that neighborhood safety is associated with substance use. There are also some racial and ethnic group differences in relationships, including that low attachment to and lack of social opportunities in neighborhoods more strongly predict substance use among whites than among other racial and ethnic groups and that family management decreases the relationship between neighborhood safety and substance use among African Americans. A better understanding of the associations among factors that influence substance use across racial and ethnic subgroups can help effectively target preventive interventions for different groups.     

Marital Conflict, Depressive Symptoms, and Functional Impairment

Guided by a stress process perspective, we investigated (a) whether marital conflict might directly lead to changes in depression and functional impairment, (b) whether marital conflict might indirectly lead to changes in functional impairment via depression, and (c) whether marital conflict might indirectly lead to changes in depression via functional impairment. We estimated a latent variable causal model using 3 waves of data from the National Survey of Families and Households (N = 1,832). Results indicated that marital conflict directly led to increases in depression and functional impairment and indirectly led to a rise in depression via functional impairment. Overall, findings suggest marital conflict is a significant risk factor for psychological and physical health among midlife and older adults.     

Confounded row–column designs

Confounded row–column designs for factorial experiments are considered and a simple method of construction using the classical method of confounding is described. Partially confounded designs are also studied and a method for generating Rao's (1946) designs is presented.