Assessing Factor Contribution to Nitrogen Concentration Levels in the Raccoon River Watershed in Iowa

Environmental Economics and Policy,

Effects of Regional Trade Agreements on Trade in Agrifood Products: Evidence from Gravity Modeling Using Disaggregated Data

The recent proliferation of regional trade agreements (RTAs) has intensified the debate on their merits. A growing literature has addressed this policy debate, focusing on the welfare and trade effects of RTAs and their likely impacts on the multilateral trading system. Some view them as stepping-stones toward multilateral trade liberalization while others see them as stumbling blocks against free trade. The existing literature has neglected some important aspects of RTAs dealing with trade in agrifood products. This study analyzes trade creation and diversion effects of the North American Free Trade Agreement (NAFTA) on trade of six selected agrifood products from 1985 to 2000. The investigation estimates an extended gravity model using pooled cross-sectional time-series regression and generalized least squares methods. The result shows that the share of intraregional trade is growing within NAFTA and that NAFTA has displaced trade with the rest of the world. NAFTA has served to boost trade significantly among its members rather than with the rest of the world. Countries participating in NAFTA have moved toward a lower degree of relative openness in agrifood trade with the rest of the world

Determinants of World Demand for U.S. Corn Seeds: The Role of Trade Costs

The United States is a large net exporter of corn seeds. Seed trade, including that of corn, has been expanding, but its determinants are not well understood. This paper econometrically investigates the determinants of world demand for U.S. corn seeds with a detailed analysis of trade costs impeding export flows to various markets, including costs associated with distance, tariffs, and sanitary and phytosanitary (SPS) regulations. The analysis relies on a gravity-like model based on an explicit specification of derived demand for seed by foreign corn producers, estimated based on data from 48 countries and for the years 1989 to 2004. An SPS count variable is incorporated as a shifter in the unit cost of seeds faced by foreign users. A sample selection framework is used to account for the determination of which trade flows are positive. All trade costs matter and have had a negative impact on U.S. corn seed exports. Tariffs matter most, followed by distance and SPS measures. �

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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Evaluation of Variation in Nitrate Concentration Levels in the Raccoon River Watershed in Iowa

The Raccoon River Watershed in Iowa has received considerable attention in the recent past due to frequent detections of nitrate concentrations above the federal drinking water standard. This paper econometrically investigates the determinants of variation of nitrate concentrations in the Raccoon River. The analysis relies on a generalized autoregressive conditional heteroscedastic process to model the serial dependence of volatility of the monthly nitrate concentrations in the Raccoon River. Monthly nitrate concentration data from Des Moines Water Works at Van Meter from 1992 to 2008 are used in the study. We found no statistically significant increasing trend in nitrate concentrations over the study period. There are substantial intra-annual variations in nitrate concentrations, and we noted a very strong seasonal pattern. Variations in rainfall and temperature contribute more to the monthly variation in nitrate concentration than do the changes in nitrogen application rates

Hydropower potential and possible hydropower schemes of Nanegal River Basin in Ecuador

The whole renewable energy discussions are currently being explored to unleash untapped hydropower potentials with innovation and new technologies. The previous studies show that most of developing countries have significant untapped hydropower potentials. Mostly, their development priority is given to the potential sites in which easy accessibility and infrastructure are prevailed, and lack of accessibility, data, and technology kept a significant number of potential sites untapped in rural basins. Ecuador is a country that has a large number of untapped hydropower potential and the lack of data, technology and resources were mainly affected for delaying the assessment of potential sites in ungagged and mountainous rural river basins. This study aimed to identify and estimate the optimum hydropower potential in a poorly gauged basin: Nanegal in Ecuador and to review the operational and planned hydropower schemes already proposed by the collaboration of the HYPOSO project team. The hydrological model (SWAT+) was used for this assessment. This study estimated the theoretical potential in the entire basin and identified the most suitable river stretches for the hydropower sites. The maximum potential capacity of the selected rivers was evaluated using the Flow Duration Curves (FDCs) developed for every channel reach. Multi-criteria analysis was performed to evaluate the most feasible project corridors for the development. The capacity enhancement of the operational plant and optimization of planned projects were also evaluated. The results showed that open-source global datasets with the combination of limited local data can be effectively used in an open-source hydrological model for producing realistic discharge data series to evaluate the existing and untapped hydropower potential. The FDC developed by comparing the actual flow data and model-simulated data has proved the reliability of the discharge results produced from the model. Due to the constraints of topography, geology and existing infrastructure development, this basin was suitable and assessed only for run-off river hydropower projects. The total power potential of the selected rivers was estimated as 110 MW by considering the 30% flow exceedance. However, this entire theoretical potential cannot be developed due to various constraints. The total potential of 51MW was selected for the development. These selected sites included five new potential sites and two alternative sites for previously proposed ones. This study provides an approach for identifying and optimising of the potential sites in rural river basins where untapped potential remains. Subsequently, the effectiveness of planned and operational projects was reviewed to a certain extent. The countries which have not thoroughly reviewed the potential sites and hold due to lack of resources and finance can use this approach to produce a more realistic pre-feasibility assessment of target areas

Effects of Regional Trade Agreements on Trade in Agrifood Products: Evidence from Gravity Modeling Using Disaggregated Data

The recent proliferation of regional trade agreements (RTAs) has intensified the debate on their merits. A growing literature has addressed this policy debate, focusing on the welfare and trade effects of RTAs and their likely impacts on the multilateral trading system. Some view them as stepping-stones toward multilateral trade liberalization while others see them as stumbling blocks against free trade. The existing literature has neglected some important aspects of RTAs dealing with trade in agrifood products. This study analyzes trade creation and diversion effects of the North American Free Trade Agreement (NAFTA) on trade of six selected agrifood products from 1985 to 2000. The investigation estimates an extended gravity model using pooled cross-sectional time-series regression and generalized least squares methods. The result shows that the share of intraregional trade is growing within NAFTA and that NAFTA has displaced trade with the rest of the world. NAFTA has served to boost trade significantly among its members rather than with the rest of the world. Countries participating in NAFTA have moved toward a lower degree of relative openness in agrifood trade with the rest of the world.</p

Enhancement of lateral load resistance of earth walls with GFRP retrofitting

Earth buildings are used in many countries, including Latin America, Africa, some part of Asia and southern Europe. These structures are built with thick walls made out of local soil. Earth walls possess heavy weight and comparable strength of other masonry and somewhat brittle behaviour. Earth walls are generally lower in tensile carrying capacity and the flexural strength, thereby susceptible for the most of the natural disasters. However, due to sustainable features associated with earth construction, it has regained popularity all over the world. This includes low embodied energy, better thermal comfort, good natural moisture buffering and attractive appearance. Relatively lower resistance to lateral forces under disaster situation has imposed some questions in the minds of the building planners to introduce earth masonry in their projects. Therefore, the aim of the current study has been focused on performance of earth masonry under seismic forces. Two main types of masonry; Compressed stabilized earth blocks (CSEB) and Cement stabilized Rammed Earth (CSRE) were considered in the current study. The performance of these walls under seismic load was experimentally determined with and without retrofitting (GFRP) methods. Shaking table was used as the main apparatus, which has one degree of freedom with 80kg capacity. A set of small-scale wall panels was made out of CSEB and CSRE and tested under scaled version of EL-Centro (EIC) earthquake north south component. As an output deflection, acceleration behaviour at the bottom, middle and top of the panel, failure modes were determined in the experimental program. According to the experimental results, seismic performance of CSEB and CSRE wall panels with retrofitting was found to be satisfactory. However, the panels without retrofitting have shown crack and failure at 6 Hz