Body posture in elderly,physically active males

The objective of this study was to evaluate the shape of anterior–posterior curvatures of the spine and to determine the values of body symmetry deviations in the frontal plane, in elderly males. The study group consisted of 34 males aged between 61 and 83 years, attending two hour-long training sessions a week. The comparative group consisted of 30 students. The photogrammetric method based on the Moire phenomenon was used to evaluate the body posture. The obtained data confirm characteristic tendencies of physiological spinal curvatures to change with the aging process. A decrease of the lumbar–sacral spinal-segment inclination and an increase of the upper thoracic spinal-segment inclination were observed in the elderly males. Whereas, the value of thoracic kyphosis lower-segment inclination was similar to the value obtained in young adult males. The stated differences indicate a flattening of lumbar lordosis and a deepening of the upper arch of thoracic kyphosis, which results in a characteristic body posture in the standing position with the head protruding and the upper trunk segment inclined. The above-mentioned observations indicate a dominance of the angular thoracic kyphosis value over the remaining spinal curvatures. These differences occur to a greater degree in elderly males.     

A Sample Size Formula for a Non-Central t Test

An elementary method of proof of the mode, median, and mean inequality is given for skewed, unimodal distributions of continuous random variables. A proof of the inequality for the gamma, F, and beta random variables is sketched.     

The Consistent System

The Consistent System (CS) is an interactive computer system for researchers in the behavioral and policy sciences and in fields with similar requirements for data management and statistical analysis. The researcher is not expected to be a programmer. The system offers a wide range of facilities and permits the user to combine them in novel ways. In particular, tools for statistical analysis may be used in combination with a powerful relational subsystem for data base management. This paper gives an overview of the objectives, capabilities, status, and availability of the system.     

An alternative method for global and partial comparison of two diagnostic systems based on ROC curves

In this paper, an alternative method for the comparison of two diagnostic systems based on receiver operating characteristic (ROC) curves is presented. ROC curve analysis is often used as a statistical tool for the evaluation of diagnostic systems. However, in general, the comparison of ROC curves is not straightforward, in particular, when they cross each other. A similar difficulty is also observed in the multi-objective optimization field where sets of solutions defining fronts must be compared with a multi-dimensional space. Thus, the proposed methodology is based on a procedure used to compare the performance of distinct multi-objective optimization algorithms. In general, methods based on the area under the ROC curves are not sensitive to the existence of crossing points between the curves. The new approach can deal with this situation and also allows the comparison of partial portions of ROC curves according to particular values of sensitivity and specificity of practical interest. Simulations results are presented. For illustration purposes, considering real data from newborns with very low birthweight, the new method was applied in order to discriminate the better index for evaluating the risk of death.     

The Exchange of Publications; An Alternative to Acquisitions

Abstract

In March 2001 the Canadian National Site Licensing Project (CNSLP) enabled the University of Saskatchewan Library to add over seven hundred electronic titles to its journal collection. The CNSLP titles introduced a critical mass of electronic journals to library patrons, offering a complex and intriguing range of supplementary content and a transformation of the experience of reading scientific journals. This article reports on the plug-ins and add-ons required to access supplementary content in the CNSLP electronic journals and explores the implications of supplementary content for readers. Serials Review 2003; 29:103–116.     

k-POD: A Method for k-Means Clustering of Missing Data

The k-means algorithm is often used in clustering applications but its usage requires a complete data matrix. Missing data, however, are common in many applications. Mainstream approaches to clustering missing data reduce the missing data problem to a complete data formulation through either deletion or imputation but these solutions may incur significant costs. Our k-POD method presents a simple extension of k-means clustering for missing data that works even when the missingness mechanism is unknown, when external information is unavailable, and when there is significant missingness in the data.

[Received November 2014. Revised August 2015.]     

An Improved Boxplot for Univariate Data

The boxplot is an effective data-visualization tool useful in diverse applications and disciplines. Although more sophisticated graphical methods exist, the boxplot remains relevant due to its simplicity, interpretability, and usefulness, even in the age of big data. This article highlights the origins and developments of the boxplot that is now widely viewed as an industry standard as well as its inherent limitations when dealing with data from skewed distributions, particularly when detecting outliers. The proposed Ratio-Skewed boxplot is shown to be practical and suitable for outlier labeling across several parametric distributions.