A unified approach to nonlinearity,structural change,and outliers

This paper demonstrates that the class of conditionally linear and Gaussian state-space models offers a general and convenient framework for simultaneously handling nonlinearity, structural change and outliers in time series. Many popular nonlinear time series models, including threshold, smooth transition and Markov-switching models, can be written in state-space form. It is then straightforward to add components that capture parameter instability and intervention effects. We advocate a Bayesian approach to estimation and inference, using an efficient implementation of Markov Chain Monte Carlo sampling schemes for such linear dynamic mixture models. The general modelling framework and the Bayesian methodology are illustrated by means of several examples. An application to quarterly industrial production growth rates for the G7 countries demonstrates the empirical usefulness of the approach.     

THE EFFECT ON POVERTY STATUS IN ISRAEL OF CONSIDERING WEALTH AND VARIABILITY OF INCOME

This paper assesses the effects of including wealth and the variability of income on the incidence of poverty and the degree of income inequality in Israel. A special survey, which includes data on the wealth and income of a national sample of Israeli families in 1963–64 and 1964–65, allows us to go beyond measures based on current income alone.
The first section reviews earlier studies of poverty in Israel. The next section looks at poverty and inequality in terms of current income, current wealth, and a combined measure of income and wealth. The combined measure is the Hansen-Weisbrod measure (HW), which equals income plus the annuity value of wealth, assuming all wealth is just consumed at the time of death. It is interesting that, in spite of the much higher wealth inequality than income inequality, the HW measure was slightly more equally distributed than income. This result occurred because the annuity component made up a low share of the total HW measure and the correlation between income and wealth was well under 1. Although overall inequality and poverty were similar for income and HW measures, the incidence of poverty by subgroup depended on the measure used.
The final section presents a dynamic view of poverty and inequality. Year-to-year changes in poverty were substantial. Because of the use of a relative poverty concept and the rise in real incomes, the real income poverty line rose by 15 percent between 1963 and 1964. Still, of those in income poverty in 1963, 37 percent managed to escape poverty in 1964. The paper shows how the degree to which poverty was stable or transitory varied substantially by age and country of origin.     

Environmental Protection by One or Both Trading Partners in a Heckscher-Ohlin-Samuelson Model

In this Heckscher-Ohlin-Samuelson model, production of a pollutive good damages production of another good within the same country. Unilateral and bilateral shifts from laissez faire to Pigouvian policy are numerically simulated for cases of low emissions and a high volume of trade, high emissions and a high volume of trade, and finally, high emissions and a low volume of trade. A country can be worse off when it becomes Pigouvian and it can be worse off when its trading partner becomes Pigouvian. Nevertheless, a simple game theory version of the model suggests a race to the top, in which all countries become Pigouvian.     

FINANCIAL FRICTIONS AND NEW EXPORTER DYNAMICS

This article studies the role of financial frictions as a barrier to international trade. We study new exporter dynamics to identify how these frictions affect export decisions. We introduce a borrowing constraint and working capital requirements into a standard model of international trade, with exports more working capital intensive than domestic sales. Our model can quantitatively account for new exporter dynamics in contrast to a model with sunk export entry costs. We provide additional evidence in support of our mechanism. We find that financial frictions reduce the impact of trade liberalization, suggesting that they constitute an important trade barrier.     

LOGISTICS STRATEGY — REVISITED

A study of logistics managers examined the roles of three logistics strategies (process, market, and information) in achieving logistics effectiveness. The results examined the dynamics of these three logistics strategies in managing trade‐offs among efficiency, internal and external organizational interactions, and meeting channel member needs. Insights for logistics practitioners, instructors, and researchers are discussed.     

Estimating Long-term Trends in Tropospheric Ozone Levels

This paper develops Bayesian methodology for estimating long-term trends in the daily maxima of tropospheric ozone. The methods are then applied to study long-term trends in ozone at six monitoring sites in the state of Texas. The methodology controls for the effects of meteorological variables because it is known that variables such as temperature, wind speed and humidity substantially affect the formation of tropospheric ozone. A semiparametric regression model is estimated in which a nonparametric trivariate surface is used to model the relationship between ozone and these meteorological variables because, while it is known that the relatinship is a complex nonlinear one, its functional form is unknown. The model also allows for the effects of wind direction and seasonality. The errors are modeled as an autoregression, which is methodologically challenging because the observations are unequally spaced over time. Each function in the model is represented as a linear combination of basis functions located at all of the design points. We also estimate an appropriate data transformation simulataneously with the functions. The functions are estimated nonparametrically by a Bayesian hierarchical model that uses indicator variables to allow a non-zero probability that the coefficient of each basis term is zero. The entire model, including the nonparametric surfaces, data transformation and autoregression for the unequally spaced errors, is estimated using a Markov chain Monte Carlo sampling scheme with a computationally efficient transition kernel for generating the indicator variables. The empirical results indicate that key meteorological variables explain most of the variation in daily ozone maxima through a nonlinear interaction and that their effects are consistent across the six sites. However, the estimated trends vary considerably from site to site, even within the same city.     

Salvatore model with equiproportional preservation of forests

A a condition for preserving their tropical rainforests, countries in the southern hemisphere are demanding equiproportional protection of temperate forests in the northern hemisphere. The Salvatore version of the Heckscher-Ohlin-Samuelson model is used to simulate the case in which it is efficient for both North and South to preserve the same proportion of their national forests. The extreme assumptions of the Salvatore model are then relaxed and the resulting effects on forest preservation examined. Although the model is highly abstract, it lends credibility to the calls for equal protection of old-growth forests.     

NO CREDIT,NO GAIN: TRADE LIBERALIZATION DYNAMICS,PRODUCTION INPUTS,AND FINANCIAL DEVELOPMENT

We study the role of financial development on the aggregate implications of reducing import tariffs on capital and intermediate inputs. We document empirically that financially underdeveloped economies feature a slower aggregate response following trade liberalization. To quantify these effects, we set up a general equilibrium model with heterogeneous firms subject to collateral constraints and estimate it using Colombian plant-level data. We find that low financial development substantially limited the gains from trade liberalization in Colombia in the early 1990s. More broadly, we find that low financial development substantially limits both the aggregate and welfare gains from tariff reductions.