LTD and RTI dependence orderings

The authors show how the approach of Capéra à & Genest (The Canadian Journal of Statistics, 1990) can be used to order bivariate distributions with arbitrary marginals by their degree of dependence in the LTD (left‐tail decreasing) or RTI (right‐tail increasing) sense. Some properties of these new orderings are given, along with applications to Archimedean copulas, order statistics and compound random variables.     

Penalized multidimensional fitting for protein movement detection

The three-dimensional structure of a given protein can take different conformations depending upon the reaction it undergoes and its substrate/cofactor/partners binding state. Various methods exist to study these conformational changes but only one, called DynDom, is clearly focused on movement detection. An alternative method is proposed, making use of multivariate data analysis, called ‘penalized Multidimensional Fitting (penalized MDF)’ based on penalized movements of points in order to approach the distances between points after movement to the distances given by the reference matrix. The objective is to detect the amino acids that undergo an important movement by fitting the distances of one conformation to the distances of the second one by modifying only the coordinates of the first one. This method is applied to three different proteins.     

Small area estimation-based prediction methods to track poverty: validation and applications

Tracking poverty is predicated on the availability of comparable consumption data and reliable price deflators. However, regular series of strictly comparable data are only rarely available. Price deflators are also often missing or disputed. In response, poverty prediction methods that track consumption correlates as opposed to consumption itself have been developed. These methods typically assume that the estimated relation between consumption and its predictors is stable over time??assumptions that cannot usually be tested directly. This study analyzes the performance of poverty prediction models based on small area estimation (SAE) techniques. Predicted poverty estimates are compared with directly observed levels in two country settings where data comparability over time is not a problem. Prediction models that employ either non-staple food or non-food expenditures or a full set of assets as predictors are found to yield poverty estimates that match observed poverty well. This offers some support to the use of such methods to approximate the evolution of poverty. Two further country examples illustrate how an application of the method employing models based on household assets can help to adjudicate between alternative price deflators.     

Longitudinal Change in Adolescent Depression and Anxiety Symptoms from before to during the COVID-19 Pandemic

This study aimed to examine changes in depression and anxiety symptoms from before to during the first 6 months of the COVID-19 pandemic in a sample of 1,339 adolescents (9–18 years old, 59% female) from three countries. We also examined if age, race/ethnicity, disease burden, or strictness of government restrictions moderated change in symptoms. Data from 12 longitudinal studies (10 U.S., 1 Netherlands, 1 Peru) were combined. Linear mixed effect models showed that depression, but not anxiety, symptoms increased significantly (median increase = 28%). The most negative mental health impacts were reported by multiracial adolescents and those under ‘lockdown’ restrictions. Policy makers need to consider these impacts by investing in ways to support adolescents’ mental health during the pandemic.     

With a focus on well-being and capabilities

Most of the applied research on capabilities and well-being makes use of quantitative data and research techniques. This paper examines the possibilities of qualitative data gathering to explore the theoretical richness (and complexity) of the capabilities framework. With this objective, the capabilities theory is translated into a framework that enables focus group discussions on well-being. It turns out to be surprisingly easy to discus issues related to the theory of capabilities, as the concepts are recognizable for the focus participants.Being able to choose and making trade offs is related to the concepts of well-being of the participants. Provided one has ‘the basic capability to cope with capabilities’, possibilities and choices increases well-being. These findings show that the capability framework can be fruitfully used for applied research on well-being and that qualitative data gathering creates opportunities that are complementary to quantitative techniques.     

Deux méthodes d'estimation pour les paramètres de processus moyenne mobile spatiaux

We consider moving average processes, {X_s, s ∈ ??}, where ?? is a triangular lattice in the plane R^2. To estimate the parameters of such processes, Adjengue & Moore (1993) have considered likelihood and gaussian pseudo-likelihood methods. We consider here two other methods. The first one is based on the estimation of the correlations and the relation between these correlations and the parameters of the process. The second relies on a linear approximation of the process. The asymptotic properties of the proposed estimators are analyzed and compared. A simulation study allows us to compare the estimators for fixed sample sizes.     

Psychotropic drug classification based on sleep–wake behaviour of rats

Summary.  The aim of the paper is to present methodology for the classification of potential psychotropic drugs on the basis of their activity. We first sketch the background of this class of drugs and then zoom in on so-called pharmacoelectroencephalogram studies. These data pose some statistical challenges. For classification purposes, we propose a flexible hierarchical discriminant analysis tool, allowing us to take the specific nature of the drug class into account, as well as the features of the mixed models, in combination with fractional polynomials, fitted to the electroencephalogram data. The method is evaluated against the background of existing methods. The method's performance is studied by using a comprehensive analysis of a large electroencephalogram data set.     

The Imaginary Audience and Personal Fable: Factor Analyses and Concurrent Validity of the “New Look” Measures

This study examined key components of the “New Look” at the imaginary audience and personal fable constructs. Toward this end, data from four samples of Belgian high school students (N= 1,458) were analyzed. Confirmatory and exploratory factor analyses failed to confirm that the measures associated with the New Look theory, the New Imaginary Audience Scale, and the New Personal Fable Scale (NPFS), tapped a common underlying construct. Only the invulnerability and omnipotence subscales of the NPFS proved to be highly related. In line with the New Look theory, boys were found to believe more strongly in their own uniqueness, invulnerability, and omnipotence than were girls. Higher scores on the invulnerability and omnipotence subscales were associated with lower levels of depression and loneliness. Finally, each aspect of the personal fable seemed to have its own specific role in the process of separation – individuation. Implications of these findings for the New Look theory of the imaginary audience and the personal fable are discussed. Suggestions for future research are put forth, with particular emphasis on the role of the invulnerability/omnipotence complex in adolescent development and behavior and on the family resemblances among the various aspects of the personal fable.     

Frailty models and copulas: similarities and differences

Copulas and frailty models are important tools to model bivariate survival data. Equivalence between Archimedean copula models and shared frailty models, e.g. between the Clayton-Oakes copula model and the shared gamma frailty model, has often been claimed in the literature. In this note we show that, in both the models, there is indeed a well-known equivalence between the copula functions; the modeling of the marginal survival functions, however, is quite different. The latter fact leads to different joint survival functions.