The gravity model is used extensively to investigate the trade flow effects of Regional Trade Agreements (RTAs). A notable feature common to previous research is the use of aggregate trade data. These studies typically report conflicting, and even negative results of the effect of RTAs on members' trade. Using recent developments in the gravity equation suggested by Baier and Bergstrand (2007) and Anderson and van Wincoop (2003) , this article demonstrates that RTA effects on members' trade depend fundamentally on whether the analysis focuses on agricultural or nonagricultural sectors, on the particular agreement analyzed, and on the length of the phase-in period that characterizes almost all RTAs. Copyright 2008, Oxford University Press.
Empirically assessing sanitary and phytosanitary regulations has proven difficult because most data sources indicate whether a regulation exists but provide no information on the type or importance of the respective measure. In this article, we construct a novel database of U.S. phytosanitary measures and match these to 47 fresh fruit and vegetable product imports from 89 exporting countries over the period 1996–2008. A product‐line gravity equation that accounts for zero trade flows is developed to investigate the trade impact of different pest‐mitigation measures. While the results suggest that phytosanitary treatments generally reduce trade, the actual restrictiveness of these measures diminishes dramatically as exporters accumulate experience, and it vanishes when exporters reach a certain threshold. The results have important policy implications considering the number of empirical studies that find a negative impact of non‐tariff measures on trade.
Optical fluorescence sol-gel sensors have been developed for the detection of carbon dioxide gas in the 0.03-30% range with a detection limit of 0.008% (or 80 ppm) and a quantitation limit of 0.02% (or 200 ppm) CO(2). Sol-gels were spin-coated on glass slides to create an organically modified silica-doped matrix with the 1-hydroxypyrene-3,6,8-trisulfonate (HPTS) fluorescent indicator. The luminescence intensity of the HPTS indicator (513 nm) is quenched by CO(2), which protonates the anionic form of HPTS. An ion pair technique was used to incorporate the lipophilic dye into the hydrophilic sol-gel matrix. TiO(2) particles (<5 microm diameter) were added to induce Mie scattering and increase the incident light interaction with the sensing film, thus increasing the signal-to-noise ratio. Moisture-proof overcoatings have been used to maintain a constant level of water inside the sensor films. The optical sensors are inexpensive to prepare and can be easily coupled to fiber optics for remote sensing capabilities. A fiber-optic bundle was used for the gas detection and shown to work as part of a multianalyte platform for simultaneous detection of multiple analytes. The studies reported here resulted in the development of sol-gel optical fluorescent sensors for CO(2) gas with sensitivity below that in the atmosphere (ca. 387 ppm). These sensors are a complementary approach to current FT-IR measurements for real-time carbon dioxide detection in environmental applications.
Recent contributions to the theoretical and empirical trade literature emphasize the channels by which exporting occurs and the duration and survival rates of trade relationships. However, for agricultural trade, few studies have considered the factors affecting export survival. This article identifies factors affecting the duration of fresh fruit and vegetable exports to the U.S. market, including U.S. sanitary and phytosanitary (SPS) policy regulations. The main findings can be summarized as follows. First, our preferred model with exporter binary variables indicates that changes in U.S. commodity prices and exporter gross domestic product have the largest impact, whereas U.S. production variability and exporter experience have the lowest impacts on the hazard rate of export duration. Second, SPS treatment requirements have persistent impacts on trade duration. Water treatment requirements quadruple the average hazard rate in the first year of a spell of service, and while the hazard rate does diminish over time, it is still nearly three times the average hazard rate, even after the fourth year of the spell of service. Similarly, a combination treatment of fumigation and cold treatment/refrigeration more than triples the average hazard rate in the first year of the spell of service, but this effect diminishes more quickly over time.
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