The Determinants and Impact of Property Rights: Land Titles on the Brazilian Frontier

This paper provides new empirical results regarding the demand and supply of title, its impact on land value, and its effects on agricultural investment on Brazilian frontiers. We use survey data from 1992 and 1993 from the state of Par  with data on the characteristics of the settlers, land tenure, land agencies involved, land values, and investment. We then turn to census data from the Brazilian agricultural census from 1940 through 1985, with observations at the municipio (county) level to examine the development of property rights to land in the southern state of Paran  during the agricultural boom between 1940 and 1970 and in the Amazon state of Par  during the period of rapid migration to the region after 1970. By examining frontiers we can follow the rise in land values, the increase in the demand for title, and the response of government. The empirical findings support the predictions of the theory regarding the effects of title and investment on land value, the role of expected change in value on demand for title, and the contribution of title in promoting investment. Governments, however, have not exactly followed the predictions of the analytical framework in supplying title. Political and bureaucratic factors play an important role in the government response to demands for title. This result suggests that researchers must pay special attention to the complex political process by which property rights are assigned in studying the emergence of tenure institutions.

Stability of PMR-polyimide monomer solutions

The stability of alcohol solutions of norborneyl capped PMR-polyimide resins was monitored during storage at ambient and subambient temperatures. Chemical changes during storage were determined spectroscopically using nuclear magnetic resonance. Resin processability and cured resin quality were determined by fabrication of unidirectional, graphite fiber composites using aged solutions and testing of selected composite properties. PMR-15 solutions exhibit nominally two weeks of useful life and PMR-2 solutions exhibit nominally two days of useful life at ambient conditions. The limiting factor is precipitation of imide reaction produces from the monomer solutions. Both solutions exhibit substantially longer useful lifetimes in subambient storage. PMR-15 shows no precipitation after several months storage at subambient temperatures. PMR-2 solutions do exhibit precipitates after extended subambient storage, however, the precipitates formed under these conditions can be redissolved. The chemical implications of these observations are discussed

The Effects of the Food Stamp Program on Energy Balance and Obesity

The Food Stamp Program (FSP) administered by the U.S. Department of Agriculture (USDA) is the cornerstone of the U.S. federal income and food safety net policy. The FSP has subsidized the food budget for millions of American households for over forty years, spending more than $60 billion per year in recent times. Prior research has demonstrated that women who participate in the FSP are more likely to be overweight or obese than eligible non-participants. This finding raises the concern that the additional income provided by FSP benefits induces participants to eat significantly more calories and gain weight, contributing to the U.S. obesity epidemic. Previous studies of the FSP have yielded mixed results. In this study we develop new conceptual and empirical models linking FSP participation, calorie consumption, physical activity, and weight gain, while controlling for genetic variation, weight history, and other physiological characteristics of individuals. The models enable us to test whether participants gained more weight, ate more calories, or engaged less in physical activity; or if previously omitted variables and individual health characteristics explain the higher prevalence of obesity among female FSP participants. We find a positive relationship between FSP participation and weight gain for a small subset of women. We do not find convincing evidence for the hypothesis that FSP participation causes obesity by increasing caloric consumption, decreasing physical activity, or some combination of the two. Our findings suggest that a positive association between FSP and weight exists, but we find no evidence of a direct causal link from one to the other. The association between weight and FSP likely results from confounding factors that make individuals more likely both to gain weight and to participate in the FSP.Food Stamp Program (FSP), Supplemental Nutrition Assistance Program (SNAP), obesity, body mass index (BMI), nutrition assistance, Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, Health Economics and Policy, Q18, H53, I12, I18, I38,

PMR polyimides with improved high temperature performance

Studies were performed to investigate the effect of substituting a hexafluoro isopropyl idene connecting group for a carbonyl group of a PMR polyimide monomeric reactant on the thermo-mechanical properties processability of graphite fiber reinforced PMR polyimide composites. Composites were fabricated utilizing PMR methodology. Monomeric reactant solutions of various stoichiometric ratios were used to impregnate Hercules HTS graphite fiber. The processing characteristics and elevated temperature (600 F) mechanical properties of the composites are described

Effects of graphite fiber stability on the properties of PMR polyimide composites

The effect of the stability of graphite fibers on composite properties after exposure in air at 600 F was investigated. Composites were fabricated from PMR-15 and PMR-2 monomer solutions, using HTS-2 and Celion 6000 graphite fibers as the reinforcement. The effect of long-term exposure in air at 600 F on composite weight loss and mechanical properties was determined. These composites exhibited a significantly increased lifetime at that temperature compared to composites fabricated from HTS fiber sold prior to 1975. The effect of the PMR-15 and PMR-II resin compositions on long-term composite performance at 600 F is also discussed

Quantifying Obesity in Economic Research: How Misleading is the Body Mass Index?

Replaced with revised version of paper 07/19/10.Obesity, percent body fat (PBF), body mass index (BMI), economic costs, measurement error, Health Economics and Policy, Research and Development/Tech Change/Emerging Technologies, C52, I10,

The Effects of the Food Stamp Program on Energy Balance and Obesity

The Effects of the Food Stamp Program on Energy Balance and ObesityFood Stamp Program (FSP), Supplemental Nutrition Assistance Program (SNAP), obesity, body mass index (BMI), nutrition assistance, Food Consumption/Nutrition/Food Safety, Q18, H53, I12, I18, I38,