A Universal QQ-Plot for Continuous Non-homogeneous Populations

This article presents a universal quantile-quantile (QQ) plot that may be used to assess the fit of a family of absolutely continuous distribution functions in a possibly non-homogeneous population. This plot is more general than probability plotting papers because it may be used for distributions having more than two parameters. It is also more general than standard quantile-quantile plots because it may be used for families of not-necessarily identical distributions. In particular, the universal QQ plot may be used in the context of non-homogeneous Poisson processes, generalized linear models, and other general models.     

Child Malnutrition and Mortality in Developing Countries: Evidence from a Cross-Country Analysis

In this article, after having identified the main clusters of food-insecure households worldwide, and summarily analyzed their livelihood profiles, we discuss the interaction and relevance of the most relevant key economic and social factors causing child malnutrition and mortality. On the basis of an essential but consistent World Bank database, covering all developing and transition countries, we also carry out a cross-country econometric analysis on relations of income and non-income factors with child malnutrition and mortality. Our main findings are threefold. First, among income factors, each country's overall level of economic development is paramount, but income distribution also plays an important role. Second, taking into account that public provision of basic services tends to increase with economic growth, each country's relative propensity to spend on basic services is significantly and negatively correlated with child malnutrition and mortality. Third, gender-related cultural factors also play a large role.     

Percentiles of sums of heavy-tailed random variables: beyond the single-loss approximation

A perturbative approach is used to derive approximations of arbitrary order to estimate high percentiles of sums of positive independent random variables that exhibit heavy tails. Closed-form expressions for the successive approximations are obtained both when the number of terms in the sum is deterministic and when it is random. The zeroth order approximation is the percentile of the maximum term in the sum. Higher orders in the perturbative series involve the right-truncated moments of the individual random variables that appear in the sum. These censored moments are always finite. As a result, and in contrast to previous approximations proposed in the literature, the perturbative series has the same form regardless of whether these random variables have a finite mean or not. For high percentiles, and specially for heavier tails, the quality of the estimate improves as more terms are included in the series, up to a certain order. Beyond that order the convergence of the series deteriorates. Nevertheless, the approximations obtained by truncating the perturbative series at intermediate orders are remarkably accurate for a variety of distributions in a wide range of parameters.     

Feasibility of a Telephone Follow-Up on Use of Emergency Contraceptive Pills in a College Health Center

Abstract

The authors examined the feasibility and effectiveness of a telephone follow-up procedure on use of emergency contraceptive pills (ECP) at a college health center. They made 264 telephone calls to the 97 women who had received ECPs during one 16-week academic semester and were successful in reaching 65 (67%) of the women, who responded with information about their experiences with ECPs. The women demonstrated a high rate of adherence to the medical regimen and reported very few side effects from ECPs; a majority said that ECPs did not affect their ability to carry out daily activities. On weighing the relative absence of problems following ECP distribution against the time, effort, and cost required to reach just over two thirds of the women, the researchers concluded that an ECP telephone follow-up procedure was neither cost-effective nor particularly useful.     

Discusion

Resumen

En esta investigación se estudia la validez de una versión castellana de la escala «Environmental Concern Scale» (ECS) llevada a cabo con 716 estudiantes. Las puntuaciones obtenidas por los sujetos proambientalistas y no proambientalistas resultan significativamente diferentes. Asímismo, se estudian las relaciones entre las actitudes hacia la preocupación por el medio ambiente, la energía nuclear y la ideología política, mostrándose una relación entre ellas de diferente intensidad. Mientras la energía nuclear está fuertemente vinculada a la ideología política, no sucede en tal medida entre ésta y las actitudes conservacionistas, ya que tanto los de derechas como los de izquierdas participan de la preocupación por el medio ambiente, aunque no en la misma medida.     

Model Selection Using Conditional Densities

In this article we propose a new method to select a discrete model f(x; θ), based on the conditional density of a sample given the value of a sufficient statistic for θ. The main idea is to work with a broad family of discrete distributions, called the family of power series distribution, for which there is a common sufficient statistic for the parameter of interest. The proposed method uses the maximum conditional density in order to select the best model.

We compare our proposal with the usual methodology based on Bayes factors. We provide several examples that show that our proposal works fine in most instances. Bayes factors are strongly dependent on the prior information about the parameters. Since our method does not require the specification of a prior distribution, it provides a useful alternative to Bayes factors.     

ARTIFICIAL STATES

We define artificial states as those in which political borders do not coincide with a division of nationalities desired by the people on the ground. We propose and compute for most countries in the world two measures of the degree to which borders may be artificial. One measures how borders split ethnic groups into two separate adjacent countries. The other measures the straightness of land borders, under the assumption the straight land borders are more likely to be artificial. We then show that these two measures are correlated with several measures of political and economic success.     

FAMILY TIES AND POLITICAL PARTICIPATION

We establish an inverse relationship between family ties and political participation, such that the more individuals rely on the family as a provider of services, insurance, and transfer of resources, the lower is one's civic engagement and political participation. We also show that strong family ties appear to be a substitute for generalized trust, rather than a complement to it. These three constructs—civic engagement, political participation, and trust—are part of what is known as social capital; therefore, in this paper, we contribute to the investigation of the origin and evolution of social capital. We establish these results using within‐country evidence and looking at the behavior of immigrants from various countries in 32 different destination places.     

Batteries assessing health related fitness in the elderly: a brief review

Evaluation of physical functioning is a key issue in clinical geriatrics and in aging research. In recent years, different physical performance batteries in which individuals are asked to perform several tasks and are evaluated using different criteria have been designed and used in elderly populations. These batteries include different types of test which range from basic motor abilities to relevant everyday activities, depending on the construct area in the domain of physical function that must be measured. This paper reviews and classifies the main physical functioning batteries that can be found in the scientific field of aging research in order to provide knowledge on selection, administration, and interpretation of this indispensable assessment tools.