The Contribution and Potential of Data Harmonization for Cross-National Comparative Research

The promise of empirical evidence to inform policy makers about their population's health, wealth, employment and economic well being has propelled governments to invest in the harmonization of country specific micro data over the last 25 years. We review the major data harmonization projects launched over this period. These projects include the Luxembourg Income Study (LIS), the Cross-National Equivalent File (CNEF), the Consortium of Household Panels for European Socio-Economic Research (CHER), the European Community Household Panel (ECHP), the European Union Statistics on Income and Living Conditions (EU-SILC), and the Survey of Health, Aging and Retirement in Europe (SHARE). We discuss their success in providing reliable data for policy analysis and how they are being used to answer policy questions. While there have been some notable failures, on the whole these harmonization efforts have proven to be of major value to the research community and to policy makers.

Topical Menthol, Ice, Peripheral Blood Flow, and Perceived Discomfort

Context : Injury management commonly includes decreasing arterial blood flow to the affected site in an attempt to reduce microvascular blood flow and edema and limit the induction of inflammation. Applied separately, ice and menthol gel decrease arterial blood flow, but the combined effects of ice and menthol gel on arterial blood flow are unknown. Objectives : To compare radial artery blood flow, arterial diameter, and perceived discomfort before and after the application of 1 of 4 treatment conditions. Design : Experimental crossover design. Setting : Clinical laboratory. Participants or Other Participants : Ten healthy men, 9 healthy women (mean age = 25.68 years, mean height = 1.73 m, mean weight = 76.73 kg). Intervention(s) : Four treatment conditions were randomly applied for 20 minutes to the right forearm of participants on 4 different days separated by at least 24 hours: (1) 3.5 mL menthol gel, (2) 0.5 kg of crushed ice, (3) 3.5 mL of menthol gel and 0.5 kg of crushed ice, or (4) no treatment (control). Main Outcome Measure(s) : Using high-resolution ultrasound, we measured right radial artery diameter (cm) and blood flow (mL/min) every 5 minutes for 20 minutes after the treatment was applied. Discomfort with the treatment was documented using a 1-to-10 intensity scale. Results : Radial artery blood flow decreased (P \u3c .05) from baseline in the ice (−20% to −24%), menthol (−17% to −24%), and ice and menthol (−36% to −39%) treatments but not in the control (3% to 9%) at 5, 10, and 15 minutes. At 20 minutes after baseline, only the ice (−27%) and combined ice and menthol (−38%) treatments exhibited reductions in blood flow (P \u3c .05). Discomfort was less with menthol than with the ice treatment at 5, 10, and 20 minutes after application (P \u3c .05). Arterial diameter and heart rate did not change. Conclusions : The application of 3.5 mL of menthol was similar to the application of 0.5 kg of crushed ice in reducing peripheral blood flood. Combining crushed ice with menthol appeared to have an additive effect on reducing blood flow

Renormalization of Drift and Diffusivity in Random Gradient Flows

We investigate the relationship between the effective diffusivity and effective drift of a particle moving in a random medium. The velocity of the particle combines a white noise diffusion process with a local drift term that depends linearly on the gradient of a gaussian random field with homogeneous statistics. The theoretical analysis is confirmed by numerical simulation. For the purely isotropic case the simulation, which measures the effective drift directly in a constant gradient background field, confirms the result previously obtained theoretically, that the effective diffusivity and effective drift are renormalized by the same factor from their local values. For this isotropic case we provide an intuitive explanation, based on a {\it spatial} average of local drift, for the renormalization of the effective drift parameter relative to its local value. We also investigate situations in which the isotropy is broken by the tensorial relationship of the local drift to the gradient of the random field. We find that the numerical simulation confirms a relatively simple renormalization group calculation for the effective diffusivity and drift tensors.Comment: Latex 16 pages, 5 figures ep

Temperature-dependent errors in nuclear lattice simulations

We study the temperature dependence of discretization errors in nuclear lattice simulations. We find that for systems with strong attractive interactions the predominant error arises from the breaking of Galilean invariance. We propose a local "well-tempered" lattice action which eliminates much of this error. The well-tempered action can be readily implemented in lattice simulations for nuclear systems as well as cold atomic Fermi systems.Comment: 33 pages, 17 figure

Symmetry Relations for Trajectories of a Brownian Motor

A Brownian Motor is a nanoscale or molecular device that combines the effects of thermal noise, spatial or temporal asymmetry, and directionless input energy to drive directed motion. Because of the input energy, Brownian motors function away from thermodynamic equilibrium and concepts such as linear response theory, fluctuation dissipation relations, and detailed balance do not apply. The {\em generalized} fluctuation-dissipation relation, however, states that even under strongly thermodynamically non-equilibrium conditions the ratio of the probability of a transition to the probability of the time-reverse of that transition is the exponent of the change in the internal energy of the system due to the transition. Here, we derive an extension of the generalized fluctuation dissipation theorem for a Brownian motor for the ratio between the probability for the motor to take a forward step and the probability to take a backward step

Long-term Labor Force Exit and Economic Well-being: A Cross-National Comparison of Public and Private Income Support

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How Exits from the Labor Force of Death Impact Household Incomes: A Four Country Comparison of Public and Private Income Support

Government policies attempt to mitigate the economic risks to households of major life transitions. This paper focuses on two such transitions that social security systems typically insure against—long term exits from the labor market (retirement, disability, unemployment insurance) and the death of a household head or spouse (survivor’s insurance). We examine labor force exits of men at various ages in four countries--Canada, Germany, Great Britain, and the United States—using data from the Cross-National Equivalent File, a matched longitudinal data set. We focus on how average net-of-tax household income changes in the years before and after the event. We find that when one measures the change in economic well-being following a labor market exit by the fraction of lost labor earnings replaced by social security income, the decline in the household’s economic well-being is substantially overstated. When we compare net-of-tax household income before and after a long term exit from the labor market, we find that such drops are much less than those implied by a social security replacement rate and that differences across countries in the average drop are much less than those based on a social security replacement rate. We find the same pattern when we focus on how net-of-tax household income changes in the years before and after the death of a head or spouse. Declines in net-of-tax household income following such a death are much lower than the decline implied by a replacement of the deceased person’s labor earnings and social security benefits by their household’s post-death social security income. But the size of the change in individualized net-of-tax income following the death of a head or spouse is greatly affected by assumptions used to adjust for changes in household size.

Overscreening in 1D lattice Coulomb gas model of ionic liquids

Overscreening in the charge distribution of ionic liquids at electrified interfaces is shown to proceed from purely electrostatic and steric interactions in an exactly soluble one dimensional lattice Coulomb gas model. Being not a mean-field effect, our results suggest that even in higher dimensional systems the overscreening could be accounted for by a more accurate treatment of the basic lattice Coulomb gas model, that goes beyond the mean field level of approximation, without any additional interactions.Comment: 4 pages 5 .eps figure

Continuum Derrida Approach to Drift and Diffusivity in Random Media

By means of rather general arguments, based on an approach due to Derrida that makes use of samples of finite size, we analyse the effective diffusivity and drift tensors in certain types of random medium in which the motion of the particles is controlled by molecular diffusion and a local flow field with known statistical properties. The power of the Derrida method is that it uses the equilibrium probability distribution, that exists for each {\em finite} sample, to compute asymptotic behaviour at large times in the {\em infinite} medium. In certain cases, where this equilibrium situation is associated with a vanishing microcurrent, our results demonstrate the equality of the renormalization processes for the effective drift and diffusivity tensors. This establishes, for those cases, a Ward identity previously verified only to two-loop order in perturbation theory in certain models. The technique can be applied also to media in which the diffusivity exhibits spatial fluctuations. We derive a simple relationship between the effective diffusivity in this case and that for an associated gradient drift problem that provides an interesting constraint on previously conjectured results.Comment: 18 pages, Latex, DAMTP-96-8

Inequalities for Light Nuclei in the Wigner Symmetry Limit

Using effective field theory we derive inequalities for light nuclei in the Wigner symmetry limit. This is the limit where isospin and spin degrees of freedom can be interchanged. We prove that the energy of any three-nucleon state is bounded below by the average energy of the lowest two-nucleon and four-nucleon states. We show how this is modified by lowest-order terms breaking Wigner symmetry and prove general energy convexity results for SU(N). We also discuss the inclusion of Wigner-symmetric three and four-nucleon force terms.Comment: 10 page