Hanle effect in the solar Ba II D2 line: a diagnostic tool for chromospheric weak magnetic fields

The physics of the solar chromosphere depends in a crucial way on its magnetic structure. However there are presently very few direct magnetic field diagnostics available for this region. Here we investigate the diagnostic potential of the Hanle effect on the Ba II D2 line resonance polarization for the determination of weak chromospheric turbulent magnetic fields......Comment: In press in astronomy and astrophysic

Magnetic field vector and electron density diagnostics from linear polarization measurements in 14 solar prominences

The Hanle effect is the modification of the linear polarization parameters of a spectral line due to the effect of the magnetic field. It has been successfully applied to the magnetic field vector diagnostic in solar prominences. The magnetic field vector is determined by comparing the measured polarization to the polarization computed, taking into account all the polarizing and depolarizing processes in line formation and the depolarizing effect of the magnetic field. The method was applied to simultaneous polarization measurements in the Helium D3 line and in the hydrogen beta line in 14 prominences. Four polarization parameters are measured, which lead to the determination of the three coordinates of the magnetic field vector and the electron density, owing to the sensitivity of the hydrogen beta line to the non-negligible effect of depolarizing collisions with electrons and protons of the medium. A mean value of 1.3 x 10 to the 10th power cu. cm. is derived in 14 prominences

Rational Impatience ?

This paper introduces a life-cycle model where impatience, instead of being driven by an exogenous discount function, results from the combination of risk aversion and mortality risks. Opting for such a formulation provides novel views on the impact of longevity extension on welfare, saving behavior and capital accumulation. In particular, we show that longevity extension may have much larger impacts on capital accumulation and equilibrium rate of interest than is usually thought. Moreover, we show that the adherence to the additive life cycle model introduced by Yaari (1965) may lead to significantly overstimating the welfare gains due to mortality risk reduction.

Risk Aversion, Intertemporal Elasticity of Substitution and Correlation Aversion

Intertemporal correlation aversion is an intuitive concept indicating whether an individual prefers lotteries concerning consumption at different moments in time to be positively or negatively correlated. I show that the difference between the coefficient of relative risk aversion and the inverse of the intertemporal elasticity of substitution is related, in a simple way, to the index of intertemporal correlation aversion.Correlation Aversion.

Risk Aversion and the Value of Risk to Life

The standard literature on the value of life relies on Yaari’s (1965) model, which includes an implicit assumption of risk neutrality with respect to life duration. To overpass this limitation, we extend the theory to a simple variety of nonadditively separable preferences. The enlargement we propose is relevant for the evaluation of life-saving programs: current practice, we estimate, puts too little weight on mortality risk reduction of the young. Our correction exceeds in magnitude that introduced by the switch from the notion of number of lives saved to the notion of years of life saved.Value of Statistical Life; Lifecycle Behavior; Cost-benefit Analysis

The Pareto principle of optimal inequality

inequality aversion, Pareto principle, uncertainty, time consistency

Risk Aversion and the Value of Risk to Life

This paper argues for an alternative methodology to estimate the value of risk to life. By relaxing the assumption of additive separability, we introduce risk aversion with respect to the length of life and show that the extended model better fits available data. This is crucial for the extrapolation stage that the evaluation of life-saving programs systematically requires. Current practice, we show, puts too little weight on the young. Our correction surpasses in magnitude that introduced by the switch from the notion of number of lives saved to the notion of years of life saved.value of statistical life; lifecycle behavior; cost-benefit analysis

Risk Aversion and the Value of Risk to Life.

The standard literature on the value of life relies on Yaari’s (1965) model, which includes an implicit assumption of risk neutrality with respect to life duration. To overpass this limitation, we extend the theory to a simple variety of nonadditively separable preferences. The enlargement we propose is relevant for the evaluation of life-saving programs: current practice, we estimate, puts too little weight on mortality risk reduction of the young. Our correction exceeds in magnitude that introduced by the switch from the notion of number of lives saved to the notion of years of life saved.Lifecycle Behavior; Life Insurance; Value of Statistical Life; Cost-Benefit Analysis;