President\u27s Note

Our annual conference has developed a pattern of high quality sessions and great opportunities for learning and fellowship. Woodie Moore has a rich history of ACL conference participation, planning, and coordination. He is imminently qualified to host us with excellence. More details are available elsewhere in this journal issue and on the ACL conference Web page- http:/ !www.acl.org/conference.htm. I look forward to seeing many of you at Evangel University in June

Taking the High Road: Protecting Open Space Along America's Highways

Examines the environmental impacts of road construction and the spiraling of land prices along new roads, and promotes best practices for linking land use and road construction. Includes success stories and recommendations for policymakers

Consumption inequality and partial insurance

This paper examines the transmission of income inequality into consumption inequality and in so doing investigates the degree of insurance to income shocks. Panel data on income from the PSID is combined with consumption data from repeated CEX cross-sections to identify the degree of insurance to permanent and transitory shocks. In the process we also present new evidence of the growth in the variance of permanent and transitory shocks in the US during the 1980s. We find some partial insurance of permanent income shocks with more insurance possibilities for the college educated and those nearing retirement. We find little evidence against full insurance for transitory income shocks except among low income households. Tax and welfare benefits are found to play an important role in insuring permanent shocks. Adding durable expenditures to the consumption measure suggests that durable replacement is an important insurance mechanism, especially for transitory income shocks

Consumption inequality and partial insurance

This paper uses panel data on household consumption and income to evaluate the degree of insurance to income shocks. Our aim is to describe the transmission of income inequality into consumption inequality by contrasting shifts in the cross-sectional distribution of income growth with shifts in the cross-sectional distribution of consumption growth. We combine panel data on income from the PSID with consumption data from repeated CEX cross-sections. The results point to some partial insurance but reject the complete market restrictions. We find a greater degree of insurance for transitory shocks and differences in the degree of insurance over time and across demographic groups. We also document the importance of durables and of taxes and transfers as a means of insurance

Imputing consumption in the PSID using food demand estimates from the CEX

In this paper we discuss an empirical strategy that allows researchers to impute consumptiondata from the CEX to the PSID. The strategy consists of inverting a demand for food equationestimated in the CEX. We discuss the conditions under which such procedure is successful inreplicating the trends of the first two moments of the consumption distribution. We argue thattwo factors appear to be empirically relevant: accounting for differences in the distribution offood expenditures in the two data sets, and accounting for the presence of measurement error inconsumption data in the CEX. In this paper we discuss an empirical strategy that allows researchers to impute consumptiondata from the CEX to the PSID. The strategy consists of inverting a demand for food equationestimated in the CEX. We discuss the conditions under which such procedure is successful inreplicating the trends of the first two moments of the consumption distribution. We argue thattwo factors appear to be empirically relevant: accounting for differences in the distribution offood expenditures in the two data sets, and accounting for the presence of measurement error inconsumption data in the CEX

Partial insurance, information,and consumption dynamics

This paper uses panel data on household consumption and income to evaluate the degree ofinsurance to income shocks. Our aim is to describe the transmission of income inequality intoconsumption inequality. Our framework nests the special cases of self-insurance and the completemarkets assumption. We assess the degree of insurance over and above self-insurance throughsavings by contrasting shifts in the cross-sectional distribution of income growth with shifts in thecross-sectional distribution of consumption growth, and analyzing the way these two measures ofhousehold welfare correlate over time. We combine panel data on income from the PSID withconsumption data from repeated CEX cross-sections in a structural way, i.e. using conventionaldemand analysis rather than reduced form imputation procedures. Our results point to some partialinsurance but reject the complete markets restriction. We find a greater degree of insurance fortransitory shocks and differences in the degree of insurance over time and across education. Wealso document the importance of durables and of taxes and transfers as a means of insurance. This paper uses panel data on household consumption and income to evaluate the degree ofinsurance to income shocks. Our aim is to describe the transmission of income inequality intoconsumption inequality. Our framework nests the special cases of self-insurance and the completemarkets assumption. We assess the degree of insurance over and above self-insurance throughsavings by contrasting shifts in the cross-sectional distribution of income growth with shifts in thecross-sectional distribution of consumption growth, and analyzing the way these two measures ofhousehold welfare correlate over time. We combine panel data on income from the PSID withconsumption data from repeated CEX cross-sections in a structural way, i.e. using conventionaldemand analysis rather than reduced form imputation procedures. Our results point to some partialinsurance but reject the complete markets restriction. We find a greater degree of insurance fortransitory shocks and differences in the degree of insurance over time and across education. Wealso document the importance of durables and of taxes and transfers as a means of insurance

Charged Particle Motion in a Highly Ionized Plasma

A recently introduced method utilizing dimensional continuation is employed to compute the energy loss rate for a non-relativistic particle moving through a highly ionized plasma. No restriction is made on the charge, mass, or speed of this particle. It is, however, assumed that the plasma is not strongly coupled in the sense that the dimensionless plasma coupling parameter g=e^2\kappa_D/ 4\pi T is small, where \kappa_D is the Debye wave number of the plasma. To leading and next-to-leading order in this coupling, dE/dx is of the generic form g^2 \ln[C g^2]. The precise numerical coefficient out in front of the logarithm is well known. We compute the constant C under the logarithm exactly for arbitrary particle speeds. Our exact results differ from approximations given in the literature. The differences are in the range of 20% for cases relevant to inertial confinement fusion experiments. The same method is also employed to compute the rate of momentum loss for a projectile moving in a plasma, and the rate at which two plasmas at different temperatures come into thermal equilibrium. Again these calculations are done precisely to the order given above. The loss rates of energy and momentum uniquely define a Fokker-Planck equation that describes particle motion in the plasma. The coefficients determined in this way are thus well-defined, contain no arbitrary parameters or cutoffs, and are accurate to the order described. This Fokker-Planck equation describes the longitudinal straggling and the transverse diffusion of a beam of particles. It should be emphasized that our work does not involve a model, but rather it is a precisely defined evaluation of the leading terms in a well-defined perturbation theory.Comment: Comments: Published in Phys. Rep. 410/4 (2005) 237; RevTeX, 111 Pages, 17 Figures; Transcription error corrected in temperature equilibration rate (3.61) and (12.44) which replaces \gamma-2 by \gamma-