A note on specification of climate variables in models of population migration

"In the literature on population migration, increasing attention has been devoted to quality-of-life factors. Measures of temperature (as proxies for climate) have frequently been employed in empirical work regarding the determinants of population migration decisions. A wide range of such specifications have been used, most of which imply restrictions on the preferences of migrants. In this paper, a variety of temperature variable specifications are analyzed and interpreted. Statistical tests for nested and nonnested hypotheses are used to compare and choose among the various specifications." The model is used to analyze interstate migration in the 48 contiguous states of the United States for the period 1975-1980.     

A note on ray curvature

Although formulae have long existed for ray curvature in an inhomogeneous cold collisionless magnetoplasma, they have not always been applied consistently. General expressions applicable to propagation in a meridional plane in an axially symmetric plasma in the presence of a poloidal potential magnetic field, such as a dipole field, are re-presented, and some previous results re-examined.     

A note on physical properties of musket fire

While the use of ballistics data and principles to clarify historical experience of firearms is to be encouraged, their application is not always straightforward. This paper emphasizes the need for care. An example is given of too sanguine reliance on period studies, specifically of muzzle velocity, and of inadequate appreciation of the physics, in particular of the Magnus force.