An ecological economic simulation model for assessing fire and grazing management effects on mesquite rangelands in Texas

In the southern Great Plains of North America, fire exclusion has contributed to many rangelands converting from native grassland to woody shrublands dominated by mesquite (Prosopis glandulosa Torr.) and cactus (Opuntia spp.), threatening ecosystem health and human livelihoods in the region. Prescribed fire is the least expensive method of treating mesquite and other undesirable plants, but its role is as a maintenance treatment to prolong the life of more expensive brush control treatments. Using a simulation model of a hypothetical 1000 ha ranch, we evaluate the biological and economic implications of management scenarios involving the regular application of summer fire to reduce mesquite and cactus over a 30-year time period. We compared the model output with experimental data to corroborate model output before evaluating various management scenarios over a range of stocking rates. Scenarios included (a) varying initial range condition, (b) different frequencies of summer burning, and (c) different initial amounts of mesquite brush. Model simulations corroborated field data sufficiently well to give confidence in the output of the model. In our simulations the option of not treating to reduce brush and cactus had a major negative impact on range condition, secondary productivity and profitability. In contrast, all simulated fire treatments improved range condition, productivity and profitability except when initial range condition was poor. Initial range condition and stocking rate were the major factors affecting both productivity and profitability. Compared to other factors over which managers have short-term control, frequency of burning and the initial amount of mesquite cover, had a relatively minor impact. Simulations indicated that the highest level of profit consistent with maintaining or improving range condition was attained when individual animal production was 92-95% that of the maximum production per animal, a situation invariably associated with relatively low stocking rates.     

Exchange rate uncertainty and US bilateral fresh fruit and fresh vegetable trade: an application of the gravity model

In order to analyse the effect of exchange rate uncertainty, we apply an empirical gravity equation to two sets of US bilateral trade data: fresh fruit over the period 1976–1999 for a panel of 26 countries; and fresh vegetables over the period 1976–2006 for a panel of nine countries. Based on panel estimation methods, and using both a moving SD measure and the Perée and Steinherr (1989) measure of exchange rate uncertainty, the results show that US bilateral fresh fruit trade has been negatively affected by exchange rate uncertainty. We also find some evidence that the exchange rate between the US dollar and the currencies of Latin American trading partners accounts for most of the negative impact of exchange rate uncertainty on bilateral trade flows in fresh fruit. In contrast, when using panel estimation methods and both measures of exchange rate uncertainty, we find no statistically significant evidence for any negative effect of exchange rate uncertainty on US bilateral fresh vegetable trade. However, we do find a statistically significant negative effect for exchange rate uncertainty when we estimate a US export gravity equation for fresh vegetables using the same panel of countries.     

Oil price forecasting under asymmetric loss

Based on the approach developed by Elliott et al. (2005), we found that the loss function of a sample of oil price forecasters is asymmetric in the forecast error. Our findings indicate that the loss oil price forecasters incurred when their forecasts exceeded the price of oil tended to be larger than the loss they incurred when their forecast fell short of the price of oil. Accounting for the asymmetry of the loss function does not necessarily make forecasts look rational.     

Real and perceived losses from unemployment: a cross-country study

This article compares the Unemployment Rate (UR) as a measure of inefficiency with several other potential measures across 18 Organization for Economic Co-operation and Development (OECD) countries. Results show that the UR is not a very good measure of relative inefficiency between countries, it overestimates the number of individuals who would get jobs if the market is clear, the Dead Weight Losses (DWLs) of UR are remarkably low even in high unemployment countries and the aggregate perceived monetary losses by the unemployed as a proportion of Gross Domestic Product (GDP) are also uniformly low, although inframarginal individuals in some countries may perceive their losses to be high.     

Estimating demand elasticities under rationing

Eliminating rationing in the United Kingdom following the Second World War was a concern for policy-makers because of potentially large fluctuations in post-war prices and the impact on unrationed goods. This study shows that in using virtual prices, elasticities can be estimated from a ‘free’ demand system consistent with observed consumer choices. Substitution estimates without accounting for rationing are misleading. In contrast, using virtual prices and estimating a ‘free’ market system yield results similar to those of the pre-war period. Results show that food rationing affected expenditure across unrationed goods. Rationing on other services had little effect on expenditure across unrationed goods.     

Evaluating the economy embedded in the Brazilian ethanol–gasoline flex-fuel car: a Real Options approach

The introduction of the flex-fuel cars in the Brazilian market in 2003 changed considerably the consumer decision-making process. Prior to this date, it was necessary to choose the automobile type only by gasoline or by ethanol fuel; today it is possible to choose a car type with both fuel options. This flexibility generates economic advantages for his owner, but what are the financial benefits of a flex-fuel car in comparison with a car using only gasoline? Geographically, where is the owner of the benefits from this flexibility located? This article presents an empirical application of the Real Options Theory in the analysis of the flex-fuel car option for five geographic Brazilian regions: Northern, Northeastern, Central-Western, Southeastern and Southern. The regional price differences as well as the consumer preferences of these regions were met. For this purpose, historical fuel prices were considered stochastic and following a Mean Reverting Stochastic process. The prediction and option values were generated by a Monte Carlo simulation. The results indicated that the option embedded on the Brazilian flex-fuel car adds considerable value to the owner in all regions and car models considered, with the Southeastern Region receiving most benefits by the flex option.     

Health IT adoption,productivity and quality in primary care

Within the last decade, there has been a growing push towards the use of electronic medical records and health information technology (IT) within primary care physician practices. Despite financial subsidies, smaller practices remain reluctant to adopt these information systems. Using a nationally representative survey of physicians, this study explores the relationship between physician, practice and area attributes and the adoption of health IT systems. Controlling for these attributes, the analysis subsequently studies the relationship between health IT, physician productivity and perceived quality of care. It finds that smaller practices and physicians with lower incomes are less likely to adopt health IT systems and that adoption varies with the type of medical conditions the practice typically treats. With regards to productivity, health IT adopters are more likely to see fewer patients and spend a larger amount of time on each visit with marginal increases in time on administrative tasks and no differences in perceived ability to deliver quality health care.     

From real estate to consumption: the role of credit markets in the USA

The aim of this article is to test whether the credit market conditions affect the strength of transmission of real estate wealth effects on household consumption in the US economy. Although many different works have dealt with the analysis of the existence of a real estate wealth effect, most of them as a reaction to the dramatic increase of housing prices in several OECD countries, there are only few papers analysing whether the consumption response depends on the positive or negative sign of the wealth shock and, as far as we know, none of them takes the effects of credit market conditions on that asymmetric response into account. This article tries to fill the existing gap in the literature on this matter. From an econometric perspective, we estimate the asymmetries in the consumption response within the momentum threshold autoregressive model (M-TAR) proposed by Enders and Siklos (2001), but following Stevans (2004), it is applied to a multivariate framework. The main results show that the credit market conditions play a significant role in the transmission of changes in real estate wealth to consumption. In addition, we find that there exists an asymmetric behaviour in the US aggregate consumption spending responses to real estate wealth and credit market shocks, which is only significant when a negative shock takes place.     

How do advertised brands benefit from private labels? An application of rational expectations models

Private labels have traditionally been viewed as a threat to advertised brands. Contrary to traditional wisdom, this study uses a two-asset rational expectations model to show that advertised brands could benefit from private labels. While the manufacturer’s advertising creates product differentiation, the retailer’s synchronous pricing strategy further enhances the product differentiation and raises profits as well as the efficiency of price discounts for the advertised brand. In addition, the existence of private labels improves the advertising efficiency, especially for newly introduced brands. The economic role of private labels is not limited to taking a free ride on the manufacturer’s advertising efforts, and this role cannot be replaced by another advertised brand.     

Politico-economic inequality and the comovement of government purchases

This paper explores the implications of economic and political inequality for the comovement of government purchases with macroeconomic fluctuations. We set up and compute a heterogeneous-agent neoclassical growth model, where households value government purchases which are financed by income taxes. A key feature of the model is a wealth bias in the political aggregation process. When calibrated to U.S. wealth inequality and exposed to aggregate productivity shocks, such a model is able to generate weaker positive comovement of government purchases than models with no political wealth bias. The wealth bias that matches the cross-sectional campaign contribution distribution by income is consistent with the mild positive comovement of government purchases in the aggregate data. We thus provide an empirically relevant example where economic and political heterogeneity matter for aggregate dynamics.