An age‐structured model of population dynamics with dominant ages,delayed behavior,and oscillations

An age‐structured model of population dynamics with age‐dominance is proposed and analyzed. Existence and uniqueness of solutions are established as well as the uniqueness and local asymptotic stability of steady‐states. Conditions for convergence to or oscillation about the steady‐state are specified in some cases.     

Contextual Variability in Young Children's Gender Ingroup Stereotype

Self-categorization theorists (Oakes, Haslam & Turner, 1994) have shown that stereotypes are not rigid and fixed, and that they vary to reflect variations in the comparative context within which they are formed. In this paper we investigate stereotype variability in a sample of 6/7-year-old children. Participants describe a specific outgroup, and then describe the ingroup (that is 'boys' or 'girls', depending on the sex of the participant). There are two conditions: in condition one the outgroup is represented by adult 'men', if participants are boys, or by adult 'women', if participants are girls. In condition two the outgroup is represented by 'girls', if participants are boys, or by 'boys', if participants are girls. Results show that stereotypical traits attributed to the ingroup change significantly with changes in the frame of reference.     

On multivariate smoothed bootstrap consistency

This paper deals with the convergence in Mallows metric for classical multivariate kernel distribution function estimators. We prove the convergence in Mallows metric of a locally orientated kernel smooth estimator belonging to the class of sample smoothing estimators. The consistency follows for the smoothed bootstrap for regular functions of the marginal means. Two simple simulation studies show how the smoothed versions of the bootstrap give better results than the classical technique.     

An automatic classification and robust segmentation procedure of spatial objects

This paper proposes a statistical procedure for the automatic volumetric primitives classification and segmentation of 3D objects surveyed with high density laser scanning range measurements. The procedure is carried out in three main phases: first, a Taylor’s expansion nonparametric model is applied to study the differential local properties of the surface so to classify and identify homogeneous point clusters. Classification is based on the study of the surface Gaussian and mean curvature, computed for each point from estimated differential parameters of the Taylor’s formula extended to second order terms. The geometrical primitives are classified into the following basic types: elliptic, hyperbolic, parabolic and planar. The last phase corresponds to a parametric regression applied to perform a robust segmentation of the various primitives. A Simultaneous AutoRegressive model is applied to define the trend surface for each geometric feature, and a Forward Search procedure puts in evidence outliers or clusters of non stationary data. An erratum to this article can be found at     

How to cut a pizza fairly: Fair division with decreasing marginal evaluations

Existential and constructive solutions to the classic problems of fair division are known for individuals with constant marginal evaluations. By considering nonatomic concave capacities instead of nonatomic probability measures, we extend some of these results to the case of individuals with decreasing marginal evaluations. Received: 12 June 2001/Accepted: 23 May 2002 An earlier version of this paper, Caltech Social Science Working Paper # 1126, was titled “How to cut a cake healthily”. We wish to thank Maristella Botticini, Erio Castagnoli, Marco Dall'Aglio, Paolo Ghirardato, Luigi Montrucchio, Marco Scarsini, Marciano Siniscalchi, as well as Maurice Salles (the Editor), an Associate Editor, and four anonymous Referees for helpful suggestions. The financial support of MIUR, CNR, and Università Bocconi is gratefully acknowledged. Part of this research was done while the first author was visiting Boston University and the California Institute of Technology, which he thanks for their hospitality.     

Minimum Distance Estimation of Search Costs Using Price Distribution

ABSTRACT

It has been shown that equilibrium restrictions in a search model can be used to identify quantiles of the search cost distribution from observedprices alone. These quantiles can be difficult to estimate in practice. This article uses a minimum distance approach to estimate them that is easy to compute. A version of our estimator is a solution to a nonlinear least-square problem that can be straightforwardly programmed on softwares such as STATA. We show our estimator is consistent and has an asymptotic normal distribution. Its distribution can be consistently estimated by a bootstrap. Our estimator can be used to estimate the cost distribution nonparametrically on a larger support when prices from heterogenous markets are available. We propose a two-step sieve estimator for that case. The first step estimates quantiles from each market. They are used in the second step as generated variables to perform nonparametric sieve estimation. We derive the uniform rate of convergence of the sieve estimator that can be used to quantify the errors incurred from interpolating data across markets. To illustrate we use online bookmaking odds for English football leagues’ matches (as prices) and find evidence that suggests search costs for consumers have fallen following a change in the British law that allows gambling operators to advertise more widely. Supplementary materials for this article are available online.     

Swinger economics

Swinging is a sexual behaviour of increasing relevance but substantially ignored in theoretical economic investigation. This paper has two major goals. The first is to describe what swinging is, discuss its economic relevance and single out the main characteristics of swinger behaviour. To this end, the Italian situation has been considered as a type of case study. The second goal is to use standard and less-standard tools from economic theory to propose some preliminary assessments of the causes and consequences of swinger couples’ behaviour. In this respect, some contributions on two-sided markets, hedonic adaptation approaches and equilibrium matching models have proved particularly useful.     

Between Transition and Enlargement: The Composition of Consumption in European Households

The article aims to specifically consider the effect of the enlargement of markets, resulting from the process of transition in Central and Eastern European countries, on the structure of household consumption. On the basis of a discriminatory analysis performed on recent data published by OECD and Eurostat, this study proposes to address three main questions: if during transition the household consumption patterns, measured by budget shares, have changed; if from this point of view, Central and Eastern European countries are similar between them and diverge from Western ones; if today there are any signs of convergence between the two groups of countries. The dissimilarity in budget share in Eastern and Western countries is proven and persistent, appearing greater in real terms than in nominal ones. On the one hand, Engel’s law is confirmed, given that at lower income levels the percentage of food consumption is greater, even though in real terms the absolute level of consumption of food has, in most cases, been reduced. On the other hand, the historical experience of Eastern countries is evident in the prolonged productive-distributive role of the State, especially in the field of essential services: home, schooling, and health.