Reunion Patterns in the Still‐Face Paradigm as Predicted by Maternal Sensitivity and Dyadic Coordination

Previous studies have suggested that the reunion episode of the still‐face procedure has the potential to reveal the regulatory resources of the mother–infant dyad that appear to be predictive of future adaptation. Nevertheless, differences across dyads with respect to these resources have received little attention, as also have the factors that are responsible for such differences. This study addresses this gap in the literature by testing whether the dyad reunion patterns can be predicted by the mothers' sensitivity assessed 3 months earlier, and by the contingent degree of the matched states in the play episode. Three dyadic patterns were identified through cluster analysis, which were characterized by playful, neutrally matched, and disrupted interactions. Multinomial logistic regression shows that the mothers' sensitivity predicts membership to the playful group, and the matched states in the play episode predict membership to the neutrally matched and disrupted groups. These findings show that the vulnerability to disrupt an ongoing interaction after a temporary perturbation is seen for only some dyads; moreover, they support the view of early regulatory development as a multidetermined achievement. Overall, these findings have important theoretical implications related to the identification of early regulatory difficulties as precursors of later developmental outcomes.     

Economic Disparities and Life Satisfaction in European Regions

This paper investigates the role of economic variables in predicting regional disparities in reported life satisfaction of European Union (EU) citizens. European subnational units (regions) are defined according to the first-level EU nomenclature of territorial units. We use multilevel modeling to explicitly account for the hierarchical nature of our data, respondents within regions and countries, and for understanding patterns of variation within and between regions. Main findings are that personal income matters more in poor regions than in rich regions, a pattern that still holds for regions within the same country. Being unemployed is negatively associated with life satisfaction even after controlled for income variation. Living in high unemployment regions does not alleviate the unhappiness of being out of work. After controlling for individual characteristics and modeling interactions, regional differences in life satisfaction still remain, confirming that regional dimension is relevant for life satisfaction.     

Two uniform machines with nearly equal speeds: unified approach to known sum and known optimum in semi on-line scheduling

We consider semi on-line scheduling on two uniform machines. The speed of the slow machine is normalized to 1 while the speed of the fast machine is assumed to be s≥1. Jobs of size J ₁,J ₂,… arrive one at a time, and each J _i (i≥1) has to be assigned to one of the machines before J _i+1 arrives. The assignment cannot be changed later. The processing time of the ith job is J _i on the slow machine and J _i /s on the fast one. The objective is to minimize the makespan. We study both the case where the only information known in advance is the total size ∑_i≥1 J _i of the jobs and the case where the only information known in advance is the optimum makespan. For each of these two cases, we almost completely determine the best possible competitive ratio of semi on-line algorithms compared to the off-line optimum, as a function of s in the range \(1\le s<\frac{1+\sqrt{17}}{4}\approx1.2808\), except for a very short subinterval around s=1.08. We also prove that the best competitive ratio achievable for known optimum is at least as good as the one for known sum, even for any number of uniform machines of any speeds.     

Comparing and generating Latin Hypercube designs in Kriging models

In Computer Experiments (CE), a careful selection of the design points is essential for predicting the system response at untried points, based on the values observed at tried points. In physical experiments, the protocol is based on Design of Experiments, a methodology whose basic principles are questioned in CE. When the responses of a CE are modeled as jointly Gaussian random variables with their covariance depending on the distance between points, the use of the so called space-filling designs (random designs, stratified designs and Latin Hypercube designs) is a common choice, because it is expected that the nearer the untried point is to the design points, the better is the prediction. In this paper we focus on the class of Latin Hypercube (LH) designs. The behavior of various LH designs is examined according to the Gaussian assumption with exponential correlation, in order to minimize the total prediction error at the points of a regular lattice. In such a special case, the problem is reduced to an algebraic statistical model, which is solved using both symbolic algebraic software and statistical software. We provide closed-form computation of the variance of the Gaussian linear predictor as a function of the design, in order to make a comparison between LH designs. In principle, the method applies to any number of factors and any number of levels, and also to classes of designs other than LHs. In our current implementation, the applicability is limited by the high computational complexity of the algorithms involved.     

Income distribution in Italy: A nonparametric analysis

Using kernel density estimation, this paper describes the real income distribution and how it evolved over time in Italy. Data are cross-sectional samples from the population of Italian households during the period 1987–1998. A non parametric test is applied to asses whether the observed changes in the distribution are statistically significant, while the presence of more than one mode in the distributions is investigated by a bootstrap test. Empirical results show that the Italian income distribution significantly changed over time, accompanied by a decreasing inequality pattern until 1991 and a subsequent rise. No marked income gains were perceived, while the real “losers” of the decade seem to be households in the middle-upper income range. Supported by the MURST project 98-13-45. We would like to thank Nicholas Longford for his precious support and encouragement, two anonymous referees, the participants of the seminar at CEPS/INSTEAD in Luxembarg, and of the 40 ^th SIS Conference in Florence, for helpful comments and suggestions. The usual disclaimers apply.     

The role of values in understanding attitudes toward lesbians and gay men

Seventy-one undergraduate participants completed the Rokeach Values Inventory and Herek's Attitudes Toward Lesbians and Gay Men scale. Six values correlated significantly with attitudes toward lesbians and gay men: salvation, obedience, and national security correlated with negative attitudes; broad-minded, a world of beauty and imaginative correlated with positive attitudes. Because values are more stable than attitudes, we suggest that those attempting to improve attitudes toward lesbians and gay men use arguments that are consonant with the existing values of prejudiced individuals. [     

A Multi-Exchange Neighborhood for Minimum Makespan Parallel Machine Scheduling Problems

We propose new local search algorithms for minimum makespan parallel machine scheduling problems, which perform multiple exchanges of jobs among machines. Inspired by the work of Thompson and Orlin (1989) on cyclic transfer neighborhood structures, we model multiple exchanges of jobs as special disjoint cycles and paths in a suitably defined improvement graph, by extending definitions and properties introduced in the context of vehicle routing problems (Thompson and Psaraftis, 1993) and of the capacitated minimum spanning tree problem (Ahuja et al., 2001). Several algorithms for searching the neighborhood are suggested.We report the results of a wide computational experimentation, on different families of benchmark instances, performed for the case of identical machines. This problem has been selected as a case study to perform a comparison among the alternative algorithms, and to discover families of instances for which the proposed neighborhood may be promising in practice. Based on the results of the experiments, we can suggest which among the many possible variants of the proposed approaches may be more promising for developing local search algorithms based on multi-exchange moves for related problems. Also, on some families of instances, which are very hard to solve exactly, the most promising multi-exchange algorithms were observed to dominate, in solution quality and in computational time, competitive benchmark heuristics.