Variability of Travel Time,Congestion, and the Cost of Travel

The variability of travel time modifies the rush hour traffic and the cost of commuting. The bottleneck model of road congestion with fixed peak-load demand is augmented of an additive random delay. When individuals have (α-β-γ) preferences, there exists a unique Nash equilibrium. The variability of travel time leads to departure rates that are spread more evenly over the rush hour than when travel times are deterministic. This equilibrium mechanism mitigates both congestion and the cost of unreliability. This implies that “single-traveler models,” which treat congestion as an exogenous phenomenon, overestimate the value of reliability for the rush hour. The application with the uniform or with the exponential distribution helps appraise the overestimation.     

Education and Cohabitation in Britain: A Return to Traditional Patterns?

Cohabitation is sometimes thought of as being inversely associated with education, but in Britain a more complex picture emerges. Educational group differences in cohabitation vary by age, time period, cohort, and indicator used. Well‐educated women pioneered cohabitation in Britain in the 1970s and 1980s. In the most recent cohorts, however, the less educated have exceeded the best educated in the proportions ever having cohabited at young ages. But the main difference by education currently seems largely a matter of timing—that is, the less educated start cohabiting earlier than the best educated. In Britain, educational differentials in cohabitation appear to be reinstating longstanding social patterns in the level and timing of marriage. Taking partnerships as a whole, social differentials have been fairly stable. Following a period of innovation and diffusion, there is much continuity with the past.     

Model-based Clustering of Sequential Data with an Application to Contraceptive Use Dynamics

ABSTRACT

Multi-state models describe the transitions people experience as life unfolds. The transition probabilities depend on sex, age, and attributes of the person and the context. Empirical evidence suggests that attributes that cannot be measured directly may at most be inferred from a long list of observable characteristics. A cluster-based, discrete-time multi-state model is presented, where transition probabilities are estimated simultaneously for several subpopulations of a heterogeneous population. The subpopulations are not defined a priori but are determined on the basis of similarities in behavior in order to determine which women exhibit similar characteristics with respect to method choice, method switch, discontinuation and subsequent resumption of contraceptive use. The data are from the life history calendar based on the Brazilian Demographic and Health Survey 1996. The parameters of the model are estimated using the EM algorithm. Seven subpopulations with heterogeneous transition probabilities are identified.     

The impact of remittances from Canada's seasonal workers programme on Mexican farms

Based on a survey of participants in Canada's Seasonal Agricultural Workers Program, the authors’ three‐stage least squares estimation of a simultaneous equation model finds that migrants’ remittances enhance on‐farm investments in Mexico, which, in turn, increase farm income. Remittances are also found to have a positive influence on non‐farm income in Mexico, by giving respondents the possibility of starting a new business and diversifying their investments. These results support the hypothesis underlying the “new economics of labour migration” that remittances contribute to economic development by relaxing the credit constraint on the investment function of family farms.     

Anti‐globalization movements and the European agenda

This article examines the relationship between the Europeanization process and the anti‐globalization agenda in Europe. Relying on the results of fieldwork research conducted since 2001 on the anti‐globalization demonstrations surrounding the European summits, it argues that these transnational protest movements are of a dual and, in part, contradictory nature. On the one hand, they have an agenda‐setting character, contributing to the formation of European public opinion. On the other hand, their influence in terms of agenda setting of European policy is constrained by their discourse style which bypasses or circumvents official discourse about European integration.     

Getting tuned in to those who are different: The role of empathy as mediator between diversity and performance

We present a theoretical model on the processes that mediate and moderate the diversity-performance relationship. Past research on this topic—for example the categorization elaboration model (van Knippenberg et al. 2004)—has often focused on information elaboration as mediator. Complementing this cognitive perspective, we propose that group diversity can also stimulate group members to engage with each other emotionally, resulting in higher levels of empathy—an emotional state which arises from the comprehension and apprehension of fellow group members’ emotional state. Empathy, in turn, is likely to enhance performance through processes within a single group member and through processes between group members. At the core of the model lies the proposition that group- as well as individual-level empathy mediate the relationship between diversity of organizational units and the performance of individual members and groups at large (multilevel mediation). Furthermore, we specify moderating conditions for the relationship between diversity and empathy. Diversity beliefs and diversity climates are introduced as second-order moderators.     

Takacs–Fiksel Method for Stationary Marked Gibbs Point Processes

Abstract. This article studies a method to estimate the parameters governing the distribution of a stationary marked Gibbs point process. This procedure, known as the Takacs–Fiksel method, is based on the estimation of the left and right hand sides of the Georgii–Nguyen–Zessin formula and leads to a family of estimators due to the possible choices of test functions. We propose several examples illustrating the interest and flexibility of this procedure. We also provide sufficient conditions based on the model and the test functions to derive asymptotic properties (consistency and asymptotic normality) of the resulting estimator. The different assumptions are discussed for exponential family models and for a large class of test functions. A short simulation study is proposed to assess the correctness of the methodology and the asymptotic results.     

An Age-Structured Model for Childhood Obesity

An age-structured model for childhood obesity at population level is fitted to empirical data in order to predict the proportion of overweighted and obese children in the 6–8 and 9–12 year old classes in the region of Valencia, Spain.