Nonequilibrium candidate Monte Carlo: A new tool for efficient equilibrium simulation

Metropolis Monte Carlo simulation is a powerful tool for studying the equilibrium properties of matter. In complex condensed-phase systems, however, it is difficult to design Monte Carlo moves with high acceptance probabilities that also rapidly sample uncorrelated configurations. Here, we introduce a new class of moves based on nonequilibrium dynamics: candidate configurations are generated through a finite-time process in which a system is actively driven out of equilibrium, and accepted with criteria that preserve the equilibrium distribution. The acceptance rule is similar to the Metropolis acceptance probability, but related to the nonequilibrium work rather than the instantaneous energy difference. Our method is applicable to sampling from both a single thermodynamic state or a mixture of thermodynamic states, and allows both coordinates and thermodynamic parameters to be driven in nonequilibrium proposals. While generating finite-time switching trajectories incurs an additional cost, driving some degrees of freedom while allowing others to evolve naturally can lead to large enhancements in acceptance probabilities, greatly reducing structural correlation times. Using nonequilibrium driven processes vastly expands the repertoire of useful Monte Carlo proposals in simulations of dense solvated systems

Determinants of Foreign Direct Investment in the Food Manufacturing Industry

This paper examines firm-specific characteristics in the food manufacturing industry that affect firms' decisions in accessing foreign markets via foreign direct investment (FDI). It also seeks to assess variations in the intensity level of multinational firm involvement in FDI given these characteristics. It finds that capital-intensive firms with higher levels of intangible assets, profitability, and knowledge capital are more likely to be MNEs. It also finds that intangible assets and knowledge capital underline the tendency of MNEs to invest more intensively abroad. Furthermore, firm size is found to play an important but not necessarily dominant role in FDI propensity and intensity.Agribusiness,

Do Eating Patterns Follow a Cohort or Change Over a Lifetime? Answers Emerging from the Literature

With the rapidly increasing American elderly population, food companies, healthcare workers, and policy makers alike are asking whether the dietary habits and food consumption patterns of this growing segment of the U.S. population will follow those of current and past elderly people or whether their cohort will eat like they did when they were younger. The purpose of this report is to review what is known about changes in nutritional intake and food consumption patterns that are associated with cohorts (generational) and with the aging process in the U.S. population. Recent literature on cohort and aging effects related to food consumption indicates that the aging effect is greater than the cohort effect. That is, diets change as people age, due to factors such as food availability, new information, new cumulative experiences, and physiological changes as bodies mature. Cohort effect is more likely due to changes in income, i.e., each succeeding cohort realizing higher real per capita income. Variation in findings is likely due to different data sources and analytic methods. Information on data sources and common databases used in these types of studies are also reviewed.Food consumption, cohort, age effect, Food Consumption/Nutrition/Food Safety,

Childhood Overweight and School Outcomes

This paper investigates the association between weight and elementary school students’ academic achievement, as measured by standardized Item Respond Theory scale scores in reading and math. Data for this study come from the 1998 cohort of the Early Childhood Longitudinal Study, Kindergarten-Fifth Grade (ECLS-K), which contains a large national sample of children between the ages of 5 and 12. Estimates of the association between weight and achievement were obtained by utilizing two regression model specifications, a mixed-effects linear model and a student-specific fixed-effects model. A comprehensive set of explanatory variables such as a household’s motivation in helping the student learn (e.g. parents’ expectations for their child’s schooling and levels of parental involvement with school activities), teacher qualification, and school characteristics are controlled for. The results show that malnourished children, both underweight and overweight, especially obese, achieve lower scores on standardized tests, particularly for mathematics, when compared to normal weight children. The outcomes are more pronounced for female students compared to male students. These results emphasize the need to reduce childhood malnutrition, especially childhood obesity.Childhood overweight, academic achievement, ECLS-K, Consumer/Household Economics, Teaching/Communication/Extension/Profession,