The Effects of Disability Insurance: Evidence from Social Security's Disabled-Widow Program

This study measures the effect of disability insurance on labor supply and health insurance coverage. The effect is identified by a policy in 1990 that increased the generosity of Social Security's disabled-widow program. Using data from the Current Population Survey, the results suggest that, in this context, disability benefits led to a one-to-one decline in labor force participation, employment, and private insurance coverage. The results imply that the demand for disability benefits may not reflect a latent demand for public health insurance

Health Information and Social Security Entitlements

This study examines whether new health information, obtained through medical screening, affects entitlements to Social Security benefits. Random assignment of information is derived from a unique feature of the Continuous National Health and Nutrition Examination Survey. To examine the effect of information on entitlements, the survey data are matched to administrative data from the Social Security Administration. The results suggest that new health information leads to delayed entitlements, particularly among workers near the early retirement age

Electromagnetism with Magnetic Charge and Two Photons

The Dirac approach to include magnetic charge in Maxwell's equations places the magnetic charge at the end of a string on which the the fields of the theory develop a singularity. In this paper an alternative formulation of classical electromagnetism with magnetic and electric charge is given by introducing a second pseudo four-vector potential, C_mu, in addition to the usual four- vector potential, A_mu. This avoids the use of singular, non-local variables (i.e. Dirac strings) in electrodynamics with magnetic charge, and it makes the treatment of electric and magentic charge more symmetric, since both charges are now gauge charges.Comment: 20 page, 0 figures. Published in AJP. Proposes the possiblity of an additional U(1) magnetic, gauge boso

Lower bound for the size of maximal nontraceable graphs

Let g(n) denote the minimum number of edges of a maximal nontraceable graph of order n. Dudek, Katona and Wojda (2003) showed that g(n)\geq\ceil{(3n-2)/2}-2 for n\geq 20 and g(n)\leq\ceil{(3n-2)/2} for n\geq 54 as well as for n\in I={22,23,30,31,38,39, 40,41,42,43,46,47,48,49,50,51}. We show that g(n)=\ceil{(3n-2)/2} for n\geq 54 as well as for n\in I\cup{12,13} and we determine g(n) for n\leq 9.Comment: 10 pages, 3 figure