Influence diagnostics in a multivariate normal regression model with general parameterization

Patriota and Lemonte [24] introduced a quite general multivariate normal regression model. This model considers that the mean vector and the covariance matrix share the same vector of parameters. In this paper we present some influence assessment for this model, such as the local influence, total local influence of an individual and generalized leverage which are discussed. Additionally, the normal curvatures for local influence studies are derived under some perturbation schemes.     

On-line bin packing with restricted repacking

Semi-on-line algorithms for the bin-packing problem allow, in contrast to pure on-line algorithms, the use of certain types of additional operations for each step. Examples include repacking, reordering or lookahead before packing the items. Here we define and analyze a semi-on-line algorithm where for each step at most k items can be repacked, for some positive integer k. We prove that the upper bound for the asymptotic competitive ratio of the algorithm is a decreasing function of k, which tends to 3/2 as k goes to infinity. We also establish lower bounds for this ratio and show that the gap between upper and lower bounds is relatively small.     

Remaining childless in affluent economies: a comparison of France, West Germany, Italy and Spain, 1994–2001 Rester sans enfant dans des sociétés d'abondances: une comparaison de la France, l'Allemagne de l'Ouest et l'Espagne, 19994–2001

This article explores why women delay childbearing and increase their likelihood to remain childless in Spain, Italy, West Germany and France. We take a macro–micro perspective and show that national institutions influence women’s life transitions, in particular partnership and motherhood. For coupled women, we find two alternative modes out of childlessness. In countries with high direct and indirect child costs, like Spain and Italy, entering a male-breadwinner couple or occupying a stable and high-income position facilitates motherhood, while in the French context motherhood is most likely in a dual-earner partnership.      

Three years later: the adaptation process of 1980 (Mariel) Cuban and Haitian refugees in South Florida

In recent years, southern Florida has experienced rapid new inflows of immigrants from Central America and the Caribbean. Since the arrival in 1980 of Mariel (Cuban) and Haitian immigrants to this area, a great deal of speculation has emerged as to the adaptation of these two groups to south Florida and the impact which their presence has wielded on the social and economic arenas of that region. In this paper, we present selected background characteristics of representative samples of both groups and discuss our empirical findings with regard to the labor market experiences, social networks, and educational experiences of the immigrants included in our sample. While the two groups minimally differ from earlier cohorts of their compatriots entering south Florida, their experiences since arriving in Florida have been quite different. Both the Cuban and Haitian immigrants arriving in 1980 demonstrate higher levels of unemployment than their counterparts who arrived earlier; however, the existence of the Cuban economic enclave in Miami did facilitate the entry of a greater number of Cubans than Haitians into the formal labor market. Initial evidence indicates that significant numbers of individuals from both groups participate in the informal labor market, often receiving less than the minimum wage.This study was conducted with the support of the Sociology Program, National Science Foundation (Grant #SES-8215567).     

Multigaussian models: The danger of parsimony

Summary MultiGaussian models have the intrinsic property of imposing very little continuity to extreme values. If the variable that is being modeled is hydraulic conductivity and the processes being studied are groundwater flow and mass transport, the absence of continuous paths of extreme values will have a retardation effect in the computed travel times. In the case of radionuclide release of nuclear waste from a deep geological repository, underestimation of travel times may lead to unsafe decision making. To demonstrate the impact of the low continuity of extreme value implicit to multiGaussian modes, travel times are computed in a site similar to Finnsj?n-one of the sites in crystaline rock studied in Sweden-using two stochastic models with the same histogram and covariance, one of them is multiGaussian, and the other is not and displays high connectivity of extreme high values. The results show that the multiGaussian model leads to less conservative results than the non-multiGaussian one. Invoking the parisimony principle to select a multiGaussian model as the simplest model that can be fully described by a mean value and a covariance function should not be justification enough for such selection. If there is not enough data to characterize the connectivity of the extreme values and therefore distriminate whether a multiGaussian model is appropriate or not, less parismonious models must also be considered.     

The social consequences of transformation in Slovakia

This article provides basic information about the transformation process in Slovakia from 1989 to 1994. Presented are some of the major results of the SOCO survey and selected important social topics are analyzed. Sociological information about income, property, consumption, and expenditures of Slovak households is given, and the economic activities of Slovak households and peoples’ attitudes to the transformation process are discussed. The article also addresses who are the winners and losers of the transition in the context of rising poverty and changes in social policy.