Grandparent-Grandchild Communication: A Review of Theoretically Informed Research

This article reviews theoretically informed research on grandparent-grandchild (GP-GC) communication. Research has been organized herein according to whether it is guided by an intergroup theory, an affect theory, or another type of theory. After reviewing research under these three broad categories, a heuristic value and degree of support for each theory are proposed for helping future researchers in their theoretical selections. Each theory is then positioned in a two-dimensional space consisting of interpersonal and intergroup dimensions to visually demonstrate theoretical lacunae that future researchers can address. We end by discussing how researchers can utilize theory as a basis for probing the role of demographic characteristics in influencing GP-GC communication.     

Optimal loan periods for undergraduate recommended reading

A model is developed for the total expected utility to borrowers of an undergraduate text book recommended by a lecturer. It takes account of the peaked demand for a book following a recommendation, measures of borrower satisfaction which involve both waiting time and reading time (loan period), and the persistence of would-be borrowers in requesting books not found on the shelves. Some parameters of the model were estimated by a method which elicited preferences of students in various choice situations; other parameters were estimated by librarians. Some specific conclusions are drawn regarding the optimal loan period of books in terms of their type and the number of copies held.     

Relationships between use of dietary supplements,caffeine and sensation seeking among college students

Abstract

Objective: Caffeine and dietary supplement (DS) use by college students is not well-documented. Given reported associations between energy drink consumption and sensation seeking, we used the Sensation Seeking Scale Form V (SSS-V) to assess relationships between sensation-seeking, caffeine, and DS use. Participants: Data from 1,248 college students from five US institutions were collected from 2009 to 2011. Methods: Linear regression was used to examine relationships between scores on the SSS-V and caffeine and DS use, demographic, and lifestyle characteristics. Results: Male sex, nonHispanic race-ethnicity, higher family income, tobacco use, consuming caffeinated beverages, more than 400?mg caffeine per day, and energy drinks with alcohol at least 50% of the time, were significantly associated with higher total SSS-V scores (P?<?0.001). Those using protein DSs had higher total, disinhibition, and boredom susceptibility SSS-V scores (Ps?<?0.001). Conclusions: Results demonstrate a positive correlation between sensation-seeking attitudes and habitual caffeine, energy drink, and DS consumption.     

The definition and measurement of similarity among legislative roll-call votes

This paper attempts to further the investigation of the close relationship between the seemingly diverse statistical techniques of Guttman scaling and principal components (factor) analysis by showing that artificial data sets composed of various kinds and combinations of cumulative scales can be analyzed in a meaningful and related way by principal components analysis. The comparison is then moved to a more abstract level through the postulation of a definition of “similarity” or association between roll-calls which is used as a standard for evaluating the two techniques. The outcome is that principal components analysis is interpreted as a refinement over Guttman scaling in the assessment of roll-call similarity, although where this extra precision is not required, Guttman scaling remains an acceptable methodology. By raising the question of the relation of technique to data to this level, it is hoped that the bases for more theoretically oriented choices of technique have been established.     

Bias Reduction for the Maximum Likelihood Estimators of the Parameters in the Half-Logistic Distribution

We derive analytic expressions for the biases of the maximum likelihood estimators of the scale parameter in the half-logistic distribution with known location, and of the location parameter when the latter is unknown. Using these expressions to bias-correct the estimators is highly effective, without adverse consequences for estimation mean squared error. The overall performance of the first of these bias-corrected estimators is slightly better than that of a bootstrap bias-corrected estimator. The bias-corrected estimator of the location parameter significantly out-performs its bootstrapped-based counterpart. Taking computational costs into account, the analytic bias corrections clearly dominate the use of the bootstrap.     

Estimation of the scale parameter after a pre-test for homogeneity in a mis-specified regression model

The risk properties of estimators of the scale parameter after a pre-test for homogeneity of the error variances in the two sample linear regression model has received quite an amount of attention in the literature. This literature typically assumes normal disturbances and a properly specified model. In this paper we consider that both equations may be mis-specified by the omission of relevant regressors and that the error distributions may belong to a wider class than the normal distribution. We derive and analyse the exact risk (under quadratic loss) of the pre-test estimator of the scale parameter for the first sub-sample.