Links between Natural Disasters, Humanitarian Assistance and Disaster Risk Reduction: A Critical Perspective

human development, climate change

The Rural Energy Challenge in Senegal: A Mission Report

human development, climate change

Development of three types of flat flexible conductors Final report, Aug. 1963 - Feb. 1964

Material properties, shielding, and coatings examined in development of flat flexible conductor cable

Rotterdam vs Almost Ideal Models: Will the Best Demand Specification Please Stand Up?

Among the many demand specifications in the literature, the Rotterdam model and the Almost Ideal Demand System (AIDS) have particularly long histories, have been highly developed, and are often applied in consumer demand systems modeling. Using Monte Carlo techniques, we seek to determine which model performs better in terms of its ability to recover the true elasticities of demand. We derive the correct formulae for the AIDS models elasticities, when the Törnqvist or two modified versions of the Stone index are used to linearize the model. The resulting linearized AIDS are compared to the full AIDS

Internal Migration, Selection Bias and Human Development: Evidence from Indonesia and Mexico

The aim of this paper is to measure the returns to migration using non-experimental data taking both observed and unobserved characteristics into account. A significant challenge related to migration research and the issues of unobserved heterogeneity is that the standard 2stage least squares estimator (2SLS) is strictly only applicable to situations with linear and continuous treatment and outcomes, both of which are not appropriate for models of migration and many outcomes of interest. Furthermore, migration is not always a binary process given that people migrate to city or non-city locations and some migrants do return. Introducing these multinomial treatment effects means that one cannot rely on standard 2SLS methods. Using panel data from Indonesia (Indonesia Family Life Survey—IFLS) and Mexico (Mexican Family Life Survey— MxFLS) and applying non-linear instrumental variable (Heckman’s treatment effects model) and maximum simulated likelihood models, we measure the impacts of migration on a broad range of variables that include socio economic outcomes such as consumption, nutrition, health status and emotional well-being for adult household members and health and schooling outcomes for children. We find consistent results for both countries that point to significant trade-offs related to migration. We found that migration can greatly improve socio-economic status through increases in income or consumption but can also be detrimental to the health status and emotional well-being of migrants and/or their extended families.Migration, selection, non-linear instrumental variables, consumption, socio-economic mobility, health, education

Estimation with Inequality Constraints on Parameters and Truncation of the Sampling Distribution.

Theoretical constraints on economic model parameters often are in the form of inequality restrictions. For example, many theoretical results are in the form of monotonicity or nonnegativity restrictions. Inequality constraints can truncate sampling distributions of parameter estimators, so that asymptotic normality no longer is possible. Sampling theoretic asymptotic inference is thereby greatly complicated or compromised. We use numerical methods to investigate the resulting sampling properties of inequality-constrained estimators produced by popular methods of imposing inequality constraints, with particular emphasis on the method of squaring, which is the most widely used method in the applied literature on estimating integrable neoclassical systems of demand equations. See Barnett and Binner (2004).Asymptotics, truncated sampling distribution, nonidentified sign, inequality constraints, bootstrap, jackknife.

Internal Migration, Selection Bias and Human Development: Evidence from Indonesia and Mexico

The aim of this paper is to measure the returns to migration using non-experimental data taking both observed and unobserved characteristics into account. A significant challenge related to migration research and the issues of unobserved heterogeneity is that the standard 2stage least squares estimator (2SLS) is strictly only applicable to situations with linear and continuous treatment and outcomes, both of which are not appropriate for models of migration and many outcomes of interest. Furthermore, migration is not always a binary process given that people migrate to city or non-city locations and some migrants do return. Introducing these multinomial treatment effects means that one cannot rely on standard 2SLS methods. Using panel data from Indonesia (Indonesia Family Life Survey—IFLS) and Mexico (Mexican Family Life Survey— MxFLS) and applying non-linear instrumental variable (Heckman’s treatment effects model) and maximum simulated likelihood models, we measure the impacts of migration on a broad range of variables that include socio economic outcomes such as consumption, nutrition, health status and emotional well-being for adult household members and health and schooling outcomes for children. We find consistent results for both countries that point to significant trade-offs related to migration. We found that migration can greatly improve socio-economic status through increases in income or consumption but can also be detrimental to the health status and emotional well-being of migrants and/or their extended families.The aim of this paper is to measure the returns to migration using non-experimental data taking both observed and unobserved characteristics into account. A significant challenge related to migration research and the issues of unobserved heterogeneity is that the standard 2stage least squares estimator (2SLS) is strictly only applicable to situations with linear and continuous treatment and outcomes, both of which are not appropriate for models of migration and many outcomes of interest. Furthermore, migration is not always a binary process given that people migrate to city or non-city locations and some migrants do return. Introducing these multinomial treatment effects means that one cannot rely on standard 2SLS methods. Using panel data from Indonesia (Indonesia Family Life Survey—IFLS) and Mexico (Mexican Family Life Survey— MxFLS) and applying non-linear instrumental variable (Heckman’s treatment effects model) and maximum simulated likelihood models, we measure the impacts of migration on a broad range of variables that include socio economic outcomes such as consumption, nutrition, health status and emotional well-being for adult household members and health and schooling outcomes for children. We find consistent results for both countries that point to significant trade-offs related to migration. We found that migration can greatly improve socio-economic status through increases in income or consumption but can also be detrimental to the health status and emotional well-being of migrants and/or their extended families.

A note on nonidentification in truncated sampling distribution estimation

Theoretical constraints on economic model parameters often are in the form of inequality restrictions. For example, many theoretical results are in the form of monotonicity or nonnegativity restrictions. Inequality constraints can truncate sampling distributions of parameter estimators, so that asymptotic normality no longer is possible. Sampling theoretic asymptotic inference is thereby greatly complicated or compromised. In Barnett and Seck (2009), which will be appear in volume 1 number 1 of the new journal, Journal of Statistics: Advances in Theory and Applications, we use numerical methods to investigate the resulting sampling properties of estimation with inequality constraints, with particular emphasis on the method of squaring, which is the most widely used method in applied literature on estimating integrable neoclassical systems of equations. In this note, we make our most important results more widely and easily available.Inequality constraints, truncated sampling distribution, nonidentification, method of squaring, numerical methods, small sample properties, asymptotic properties

Long term behaviour of singularly perturbed parabolic degenerated equation

In this paper we consider models for short-term, mean-term and long-term morphodynamics of dunes and megariples. We give an existence and uniqueness result for long term dynamics of dunes. This result is based on a time-space periodic solution existence result for degenerated parabolic equation that we set out. Finally the mean-term and long-term models are homogenized