Nonlinear models for ground-level ozone forecasting

One of the main concerns in air pollution is excessive tropospheric ozone concentration. The aim of this work is to develop statistical models giving shortterm forecasts of future ground-level ozone concentrations. Since there are few physical insights about the dynamic relationship between ozone, precursor emissions and/or meteorological factors, a nonparametric and nonlinear approach seems promising in order to specify the forecast models. First, we apply four nonparametric procedures to forecast daily maximum 1-hour and maximum 8-hour averages of ozone concentrations in an urban area. Then, in order to improve the forecast performances, we combine the time series of the forecasts. This idea seems to give encouraging results. This work was supported by a MURST grant. The authors would like to thank two anonymous referees for their helpful comments.     

The Collaborations-Relations Between Western (Secular) Law and Religious<Emphasis Type="Italic"> Nomoi</Emphasis> Groups in Today’s Multicultural Context: The Cases of France and Canada

In the last decade, under the pressing processes of immigration and globalisation, many Western constitutional democracies have moved from a number of religions sharing a common culture to today’s age of diversity. What current democracies are facing is the lack of overlapping consensus over basic constitutional “values”. The nature, scope and force of such values are likely to be affected by competing and, sometimes, contested fundamental reasons and worldviews. From here stems the dilemma between “unity” and “diversity”. This essay starts with a broad consideration on the principle of religious freedom, strictly related to the separation as well as collaboration between secular States and Churches; then the author analyses two case-studies (France and Canada), pointing out some specific legal approaches. In particular he focuses the analyses over the French “droit commun” and the Canadian arbitral tribunals that, especially in family law, allow disputes to be arbitrated using religious jurisdictions.     

Why still marry? The role of feelings in the persistence of marriage as an institution1

Despite cohabitation becoming increasingly equivalent to marriage in some of the most ‘advanced’ Western European societies, the vast majority of people still marry. Why so? Existing theories, mostly based on various approaches tied to cognitive decision‐making, do not provide a sufficient explanation of the persistence of marriage. In this article, we argue that feelings attached to marriage, i.e. the affective evaluation of those involved in a partner relationship concerning marriage as opposed to cohabitation, explain the persistent importance of marriage as an institution. We argue that socialization, biological and social‐structural factors affect these affective evaluations. We provide a test of our hypotheses using a longitudinal study of young adults in the Netherlands. The results of our analyses are consistent with a central role of feelings in the decision to marry, as well as with a role for key moderating factors such as gender.     

Fitting logistic multilevel models with crossed random effects via Bayesian Integrated Nested Laplace Approximations: a simulation study

Fitting cross-classified multilevel models with binary response is challenging. In this setting a promising method is Bayesian inference through Integrated Nested Laplace Approximations (INLA), which performs well in several latent variable models. We devise a systematic simulation study to assess the performance of INLA with cross-classified binary data under different scenarios defined by the magnitude of the variances of the random effects, the number of observations, the number of clusters, and the degree of cross-classification. In the simulations INLA is systematically compared with the popular method of Maximum Likelihood via Laplace Approximation. By an application to the classical salamander mating data, we compare INLA with the best performing methods. Given the computational speed and the generally good performance, INLA turns out to be a valuable method for fitting logistic cross-classified models.     

Integrating macro- and micro-level approaches in the explanation of population change

Demographers study population change across time and place, and traditionally they place a strong emphasis on a long-range view of population change. This paper builds on current reflections on how to structure the study of population change and proposes a two-stage perspective. The first stage, discovery, focuses on the production of novel evidence at the population level. The second stage, explanation, develops accounts of demographic change and tests how the action and interaction of individuals generate what is discovered in the first stage. This explanatory stage also provides the foundation for the prediction of demographic change. The transformation of micro-level actions and interactions into macro-level population outcomes is identified as a key challenge for the second stage. Specific instances of research are discussed.     

The power of (extended) monitoring in robust clustering

We complement the work of Cerioli, Riani, Atkinson and Corbellini by discussing monitoring in the context of robust clustering. This implies extending the approach to clustering, and possibly monitoring more than one parameter simultaneously. The cases of trimming and snipping are discussed separately, and special attention is given to recently proposed methods like double clustering, reweighting in robust clustering, and fuzzy regression clustering.     

Italian Adult Gambling Behavior: At Risk and Problem Gambler Profiles

The present study examined adult gambling behaviours from a local perspective in order to assess the adult at risk and problem gambler’s profile stratified by genre and by different forms of game. 4773 Italian adults from 18 to 94 years old were administered a survey to assess socio-cultural information related to gambling behaviour and the SOGS to evaluate gambling behaviour severity. Logistic regression evidenced that both at risk and problem gamblers are associated with male gender, players that use to play to more than one game, gambling with strategy-based games. People with a gambler father or both parents who used to gamble were significantly more associated with problem gambling behaviour than participants with non-gambler parents. These results present adult profiles of at risk and problem providing a more clear understanding about the relationships between gambling behavior severity and type of gambling.     

A model of goal dynamics in technology-based organizations

The purpose of the present work is to build a suitable system dynamics model for goal dynamics in organizations, as proposed by Barlas and Yasarcan (2008). The proposed model does not bear any ambition of being exhaustive: the main objective of this paper is to propose a model of goal dynamics in which Goal Setting, Management by Objectives and Training are viewed as human resource practices able to enhance workers’ goal commitment, and therefore, improve organizational performance. In the first part of this paper, an analysis of the Goal Setting Theory and the role of goal setting practices, in bettering worker's performance, are stressed. In the second part, a case-study, the causal loop and a quantitative model of goal dynamics in organizations are described. In the third part, behaviour reproduction testing, optimization analysis for parameter estimation and scenario analysis are presented. Limitations of the present research and conclusions are finally discussed.     

Using Entropic Tilting to Combine BVAR Forecasts With External Nowcasts

This article shows entropic tilting to be a flexible and powerful tool for combining medium-term forecasts from BVARs with short-term forecasts from other sources (nowcasts from either surveys or other models). Tilting systematically improves the accuracy of both point and density forecasts, and tilting the BVAR forecasts based on nowcast means and variances yields slightly greater gains in density accuracy than does just tilting based on the nowcast means. Hence, entropic tilting can offer—more so for persistent variables than not-persistent variables—some benefits for accurately estimating the uncertainty of multi-step forecasts that incorporate nowcast information.     

The Interrelations Between Cohabitation,Marriage and First Birth in Germany and Sweden

We study the interrelationships between union-formation forms and fertility in Swedish and West German female cohorts born in 1949–1971. We apply simultaneous hazard models, permitting the presence of correlated unobserved heterogeneity. This method allows us to control for country-specific composition of the population with respect to several socio-economic variables, as well as with respect to unobserved factors jointly affecting childbearing and union formation behavior. Our results confirm that partnership formation and the transition to parenthood are partially interchangeable. Net of those selection effects, we find that the impact of being in a union on first birth is higher in Sweden than in Germany, in particular for cohabitation.