Import demand for Brazilian ethanol: a cross-country analysis

This study presents an empirical analysis of the import demand for Brazilian ethanol by its six major foreign buyers. The primary objectives of this study were to identify the economic factors affecting the demand for ethanol imports and to derive long-run price and income elasticities of import demand. These elasticities could be used to analyze the impact of government policies such as mandatory gasoline/ethanol blends and import tariffs. Import demand models were estimated with ordinary least squares (OLS), using quarterly time series data for the 1997–2007 time period. The results suggest that the factors influencing the import demand for ethanol vary across countries. Markets adopting mandatory blends of renewable fuels tend to have less price elastic import demand schedules. Ethanol imports were found to be price elastic and statistically significant in the Caribbean region (?1.66), Mexico (?2.08), Japan (?1.44) and Nigeria (?1.38), while import demand was price inelastic and not statistically different from zero in the US (?0.76) and Europe (?0.21). The regression results could not determine the impacts of import tariffs for the United States, Mexico and Nigeria on the quantity of imports because tariffs did not vary during the time period studied. Results show that mandatory gasoline/ethanol blends have been an important determinant of ethanol imports.     

Reliability and input-data induced uncertainty of the EPIC model to estimate climate change impact on sorghum yields in the U.S. Great Plains

Crop simulation models are frequently used to estimate the impact of climate change on crop production. However, few studies have evaluated the model performance in ways that most researchers practiced in climate impact studies. In this article, we examined the reliability of the EPIC model in simulating grain sorghum (Sorghum bicolor (L.) Moench) yields in the U.S. Great Plains under different climate scenarios, namely in years with normal or extreme temperature and precipitation. We also investigated model uncertainties introduced by input data that are not site-specific but commonly used or available for climate change studies. Historical field trial data of sorghum at the Mead Experimental Center, NE, were used for model evaluations. The results showed that overall model reliability was about 56%. The mean absolute relative error (absRE) was about 29%. The degree of accuracy and reliability varied with climate-classes and nitrogen (N)-treatments. The largest bias occurred in drought years (RE = ?25%) and the most unreliable results were found in N-0 treatment (reliability = 32%). There was more than 69% probability that input-data-induced uncertainties were limited to less than 20% of absRE. Our results support the application of the EPIC model to climate change impact studies in the U.S. Great Plains. However, efforts are needed to improve the accuracy in simulating crop responses to extreme water- and nitrogen-stressed conditions.     

Development and preparation of lead-containing paint films and diagnostic test materials

Lead in paint continues to be a threat to children's health in cities across the United States, which means there is an ongoing need for testing and analysis of paint. This ongoing analytical effort and especially development of new methods continue to drive the need for diagnostic testing materials that provide the analytical challenges of real-world paints. To this end, 31 different types of paint test materials were developed and prepared. Preparation of the materials included development of lead-containing paint films yielding an overall relative standard error for one individual test sample being less than 10%. The 31 diagnostic test materials prepared with these paint films included two lead pigments; lead concentrations from nominally 0 to 2.0 mg lead/cm(2) (0 to 5% lead by weight); overlayers of both "lead-free," oil-based and water-based paints; Al, Ba, and Mg as potential chemical interferents; red and black potential color interferents; and substrates of wood, metal, masonry, and plaster. These materials challenge each step in method development and evaluation, including paint sample collection and preparation, lead extraction, and measurement of solubilized lead. When the materials were used to test performance of a new lead-in-paint testing method based on extraction using a rotor/stator method and measurement using turbidimetry, the results agreed to within ±20% of the expected lead values for 30 out of 31 of the diagnostic test materials, thereby demonstrating their levels of quality and utility.     

Modeling spatio-temporal wildfire ignition point patterns

We analyze and model the structure of spatio-temporal wildfire ignitions in the St. Johns River Water Management District in northeastern Florida. Previous studies, based on the K-function and an assumption of homogeneity, have shown that wildfire events occur in clusters. We revisit this analysis based on an inhomogeneous K-function and argue that clustering is less important than initially thought. We also use K-cross functions to study multitype point patterns, both under homogeneity and inhomogeneity assumptions, and reach similar conclusions as above regarding the amount of clustering. Of particular interest is our finding that prescribed burns seem not to reduce significantly the occurrence of wildfires in the current or subsequent year over this large geographical region. Finally, we describe various point pattern models for the location of wildfires and investigate their adequacy by means of recent residual diagnostics.

Temporal trends of polybrominated diphenyl ethers and hexabromocyclododecane in Swedish Peregrine Falcon (Falco peregrinus peregrinus) eggs

A temporal trend study of brominated flame retardants in eggs from peregrine falcon (Falco peregrinus peregrinus), a terrestrial bird of prey, is presented. Eggs collected between 1974 and 2007 were analyzed for the major constituents of the Penta-, Octa- and Decabromodiphenyl ether technical products (BDE-47, -99, -100, -153, -183 and -209), and hexabromocyclododecane (HBCD). Concentrations of BDE-99, -100, -153, -183, -209 and HBCD increased from 1974 to 2000. After the early 2000s, BDE-99, -100, -153 and -183 concentrations decreased, whereas BDE-209 and HBCD concentrations continued to increase. No temporal trend was detected for BDE-47. Rates of increase also differed, with BDE-99 and -100 increasing 3-fold between the 1980s and mid-1990s, and BDE-153 and -183 increasing approximately 10-fold during the same period. The average yearly increase was 15% and 11% for BDE-209 and HBCD, respectively, based on log-linear regression trends. There is a change in BDE congener patterns over time, with a shift from the predominance of BDE-99 and -47 until the late 1980s, to BDE-153 becoming the predominant congener later on. BFR temporal trends in Swedish peregrine falcon eggs reflect European BFR usage patterns.     

The social viability and environmental sustainability of direct action land reform settlements in the Amazon

State-led agrarian reform (SLAR) settlements established in the Amazon in the 1970s led to environmental degradation and mixed socioeconomic outcomes. More recently, direct-action land reform (DALR) settlements have proliferated, which are leading to new forest clearing in the name of agrarian reform. The emergence of DALR begs questions about social and environmental outcomes in recent Amazon settlements. This paper compares DALR settlements in two different regions of the eastern Amazon: the South of Pará and the Transamazon. Analysis of household survey data shows that DALR settlements in the two study areas differ substantially in terms of their histories of formation and regional contexts. However, social and environmental outcomes do not always differ among the two study areas, which in turn resemble older SLAR settlements.