Fractional Spectral Moments for Digital Simulation of Multivariate Wind Velocity Fields

In this paper, a method for the digital simulation of wind velocity fields by Fractional Spectral Moment function is proposed. It is shown that by constructing a digital filter whose coefficients are the fractional spectral moments, it is possible to simulate samples of the target process as superposition of Riesz fractional derivatives of a Gaussian white noise processes. The key of this simulation technique is the generalized Taylor expansion proposed by the authors. The method is extended to multivariate processes and practical issues on the implementation of the method are reported.Comment: 12 pages, 2 figure

Intergenerational family ties and the diffusion of cohabitation in Italy

Cohabitation has been spreading in the population during the last thirty years, and this is one of the most striking aspects of wider social changes that have taken place throughout the industrialized world. However, this change did not take place uniformly across Europe. The purpose of this paper is to contribute to the current debate around the compatibility of cohabitation experiences with the Italian cultural context. Using an individual-level diffusion approach we obtain results that are consistent with the crucial role that family ties play in the choice of cohabitation in place of (or before) marriage.cohabitation, diffusion, family ties, first union, Italy

The impact of health behaviors and life quality on gender differences in mortality

Since gender-specific mortality differences are known a great deal of research has been conducted on this subject. The resulting hypotheses for explaining male excess mortality can be sub-divided into two basic categories: the biological approach (focusing on biological and genetic factors) and the non-biological approach (focusing on behavioral and environmental factors). It has been proven impossible to explain the observed trends in mortality differences between women and men by relying solely on one of the two groups of theories. Recent studies indicate that the majority of the female survival advantage can be attributed to gender behaviors while the impact of biological factors seems to be limited to 1-2 years in life expectancy at birth. The main goal of this paper is to analyze the impact of gender-specific health behaviors and gender differences in life quality using micro level data for Western Germany.Germany, life styles, mortality, sex differentials

Ageing dynamics of a human-capital-specific population: A demographic perspective

Background: Research on how rising human capital affects the consequences of population ageing rarely considers the fact that the human capital of the elderly population is composed in a specific way that is shaped by their earlier schooling and work experience. For an elderly population of a fixed size and age-sex composition, this entails that the higher its human capital, the greater the total amount of public pensions to be paid. Objective: The main purpose of this paper is to analyse the link between human capital and retiree benefits and its effect on population ageing from a demographic viewpoint. Methods: We construct an old age dependency ratio (OADR), in which each person, whether in the numerator or the denominator, is assigned the number of units corresponding to his/her level of human capital. Based on data for Italy, we study the dynamics of this human-capital-specific OADR with the help of multistate population projections to 2107. Results: Our results show that under specific conditions a constant or moderately growing human capital may aggravate the consequences of population ageing rather than alleviate them. Conclusions: With those findings, the authors would like to stimulate the debate on the search for demographic and/or socio-economic solutions to the challenges posed by population ageing