Quantum Hall fractions in ultracold fermionic vapors

We study the quantum Hall states that appear in the dilute limit of rotating ultracold fermionic gases when a single hyperfine species is present. We show that the p-wave scattering translates into a pure hard-core interaction in the lowest Landau level. The Laughlin wavefunction is then the exact ground state at filling fraction nu=1/3. We give estimates of some of the gaps of the incompressible liquids for nu = p/(2p+-1). We estimate the mass of the composite fermions at nu =1/2. The width of the quantum Hall plateaus is discussed by considering the equation of state of the system.Comment: RevTex, 4 pages, 3 fig

Promoting Social Participation for Healthy Ageing - A Counterfactual Analysis from the Survey of Health, Ageing, and Retirement in Europe (SHARE)

Promoting social participation of the older population (e.g. membership in voluntary associations) is often seen as a promising strategy for 'healthy ageing' in Europe. Although a growing body of academic literature challenges the idea that the link between social participation and health is well established, some statistical evidence suggest a robust positive relationship may exist for older people. One reason could be that aged people have more time to take part in social activities (due to retirement, fewer familial constraints, etc.); so that such involvement in voluntary associations contributes to maintain network size for social and emotional support; and preserves individuals' cognitive capacities. Using SHARE data for respondents aged fifty and over in 2004, this study proposes to test these hypotheses by evaluating the contribution of social participation to self-reported health (SRH) in eleven European countries. The probability to report good or very good health is calculated for the whole sample (after controlling for age, education, income and household composition) using regression coefficients estimated for individuals who do and for those who do not take part in social activities (with correction for selection bias in these two cases). Counterfactual national levels of SRH are derived from integral computation of cumulative distribution functions of the predicted probability thus obtained. The analysis reveals that social participation contributes by three percentage points to the increase in the share of individuals reporting good or very good health on average. Higher rates of social participation could improve health status and reduce health inequalities within the whole sample and within every country. Our results thus suggest that 'healthy ageing' policies based on social participation promotion may be beneficial for the aged population in Europe.Healthy ageing, Self-reported health, Social participation, Social capital, SHARE data, Counterfactual analysis, Stochastic dominance

Social Capital and Health of Older Europeans

This research uses a time-based approach of the causal relationship (Granger-like)between health and social capital for older people in Europe. We use panel data from waves 1 and 2 of SHARE (the Survey of Health, Ageing, and Retirement in Europe)for the analysis. Additional wave 3 data on retrospective life histories (SHARELIFE)are used to model the initial conditions in the model. For each of the first 2 waves, a dummy variable for involvement in social activities (voluntary associations, church, social clubs, etc.) is used as a proxy for social capital as involvement in Putnamesque associations; and seven health dichotomous variables are retained, covering a wide range of physical and mental health measures. A bivariate recursive Probit model is used to simultaneously investigate (i) the influence of baseline social capital on current health - controlling for baseline health and other current covariates, and (ii)the impact of baseline health on current participation in social activities - controlling for baseline social capital and other current covariates. As expected, we account for a reversed causal effect: individual social capital has a causal beneficial impact on health and vice versa. However, the effect of health on social capital appears to be significantly higher than the social capital effect on health. These results indicate that the sub-population reaching 50 years old in good health has a higher propensity to take part in social activities and to benefit from it (social support, etc.). Conversely, the other part of the population in poor health at 50, may see its health worsening faster because of the missing beneficial effect of social capital. Social capital may therefore be a potential vector of health inequalities.Healthy Ageing, Social Capital, Health Inequality, Granger Causality, Panel Data.

Did the ever dead outnumber the living and when? A birth-and-death approach

This paper is an attempt to formalize analytically the question raised in "World Population Explained: Do Dead People Outnumber Living, Or Vice Versa?" Huffington Post, \cite{HJ}. We start developing simple deterministic Malthusian growth models of the problem (with birth and death rates either constant or time-dependent) before running into both linear birth and death Markov chain models and age-structured models