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. �

Perturbative correction to the adiabatic approximation for (d,p)(d,p) reactions

The adiabatic distorted wave approximation (ADWA) is widely used by the nuclear community to analyse deuteron stripping ($d$,$p$) experiments. It provides a quick way to take into account an important property of the reaction mechanism: deuteron breakup. In this work we provide a numerical quantification of a perturbative correction to this theory, recently proposed in [R.C. Johnson, J. Phys. G: Nucl. Part. Phys. 41 (2014) 094005] for separable rank-one nucleon-proton potentials. The correction involves an additional, nonlocal, term in the effective deuteron-target ADWA potential in the entrance channel. We test the calculations with perturbative corrections against continuum-discretized coupled channel predictions which treat deuteron breakup exactly

Economic Perspectives on GMO Market Segregation

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Weather-based models for predicting grape powdery mildew (Uncinula necator (Schwein) Burrill) epidemics

El oídio de la vid (Vitis vinifera L.), causado por Uncinula necator (Schwein) Burrill, es una enfermedad fúngica relevante en viñedos de la provincia de Mendoza, ocasionando pérdidas de producción y degradación de la calidad del fruto cosechado. Durante seis campañas agrícolas (2001/02; 2002/03; 2005/06; 2007/08; 2008/09; 2009/10), en un parral del cultivar susceptible Chenín (EEA INTA Mendoza, Luján de Cuyo), se observó la evolución de la incidencia del oídio en racimos (como tasa de incremento epidémica diaria), desde floración hasta envero. A partir de registros térmico-hídricos horarios (monitoreados con sensores ubicados en la parte superior del canopeo) se calcularon variables meteorológicas en los 15 días previos a cada observación del progreso de la epidemia. Con variables que integran efectos de la temperatura, humedad del aire y frecuencia de precipitaciones ligeras sobre el incremento de la enfermedad en función del tiempo, se ajustaron modelos de regresión logística para estimar las probabilidades de ocurrencia de tasas epidémicas categorizadas (severa, moderada y nula), logrando una precisión de predicción máxima de 92,5% (modelo bivariado, N=40). Las predicciones del modelo univariado (seleccionado por "Stepwise"; precisión de predicción: 87,5%) se validaron satisfactoriamente con la curva epidémica observada en 2000/2001. Los valores estimados por estos modelos podrían complementar a las observaciones epidémicas y emitir alarmas regionales que sustenten la toma de decisión de control químico.Powdery mildew, caused by Uncinula necator (Schwein) Burrill is one of the most damaging disease affecting grapevines (Vitis vinifera L.) in Mendoza and worldwide, reducing yield and fruit quality. Throughout six growing seasons (2001/02; 2002/03; 2005/06; 2007/08; 2008/09; 2009/10), powdery mildew incidence values (expressed as daily epidemic increment rates) were observed in clusters from flowering to onset of ripening (change of color of the grape berries), in a grapevine planted with the susceptible Chenin cultivar at the EEA INTA Mendoza (Luján de Cuyo). From hourly values of thermal-moisture elements recorded by upper canopy sensors, meteorological variables were calculated in the 15 previous days of each epidemic observation. Using variables which integrate the effects of air temperature and humidity and frequency of light precipitations over the epidemic progress, logistic models were adjusted for estimating the probability of occurrrence of severe, moderate and nil epidemic increment rates, reaching maximum prediction accuracy of 92.5% (two variable models, N=40). Predicted values by the univariate model (selected by Stepwise procedure; prediction accuracy: 87.5%) were validated with the epidemic curve observed during 2000/2001 growing season. These model predictions could complement epidemic observations, giving regional scale to warning systems for improving the decision making process regarding disease chemical control.Fil: Oriolani, Enrique J. A.. Instituto Nacional de Tecnología Agropecuaria (Argentina). Estación Experimental Agropecuaria Mendoza.Fil: Moschini, Ricardo C.. Instituto de Clima y Agua. CIRN. INTA Castelar.Fil: Salas, Sergio. Instituto Nacional de Tecnología Agropecuaria (Argentina). Estación Experimental Agropecuaria Mendoza.Fil: Martinez, Malvina I.. Instituto de Clima y Agua. CIRN. INTA Castelar.Fil: Banchero, Santiago. Instituto de Clima y Agua. CIRN. INTA Castelar

Strength of Protection for Geographical Indications: Promotion Incentives and Welfare Effects

We address the question of how the strength of protection for geographical indications (GIs) affects the GI industry\u27s promotion incentives, equilibrium market outcomes, and the distribution of welfare. Geographical indication producers engage in informative advertising by associating their true quality premium (relative to a substitute product) with a specific label emphasizing the GI\u27s geographic origin. The extent to which the names/words of the GI label can be used and/or imitated by competing products—which depends on the strength of GI protection—determines how informative the GI promotion messages can be. Consumers’ heterogeneous preferences (vis-à-vis the GI quality premium) are modeled in a vertically differentiated framework. Both the GI industry and the substitute product industry are assumed to be competitive (with free entry). The model is calibrated and solved for alternative parameter values. Results show that producers of the GI and of the lower-quality substitute good have divergent interests: GI producers are better off with full protection, whereas the substitute good\u27s producers prefer intermediate levels of protection (but they never prefer zero protection because they benefit indirectly if the GI producers’ incentives to promote are preserved). For consumers and aggregate welfare, the preferred level of protection depends on the model\u27s parameters, with an intermediate level of protection being optimal in many circumstances

METODICA PREDITTIVA PER LA VALUTAZIONE DEI DIFETTI SU LAMINATI SOTTILI IN LEGA AA3005 PER IL SETTORE PACKAGING DERIVANTI DA INCLUSIONI SOLIDE NEI BAGNI DI FUSIONE

Nel presente lavoro si è cercato di mettere a punto una metodica di prova per l’ individuazione predittiva deimicrofori nei laminati sottili in lega di alluminio sin dalla fase di fusione delle placche (cioè a monte del ciclo difabbricazione.)Mettendo in relazione ripetutamente i risultati del “test PREFIL®” [1], effettuato nella fase di colata delmetallo, in grado di quantificare la presenza di inclusioni solide e ossidi, con i risultati, in termini di microfori,rilevati sul laminato al termine della laminazione a freddo mediante l’utilizzo di un rilevatore ottico laser,è stato possibile ricavare relazioni abbastanza affidabili circa la previsione delle difettosità sul laminato aspessore finale, già dalla fase di colata

Meteorological-Based Predictions of Wheat Head Blight Epidemic in the Southern Argentinean Pampas Region

In Argentina, head blight is a highly risky disease (caused by Fusarium graminearum), although its occurrence is sporadic depending on prevalent environmental variables. These traits stimulated the development of predictive models of head blight occurrence which would help growers in the selection of control strategies. Empirical equations for predicting head blight incidence were developed at Pergamino (33° 56′ S, 60° 30′ W) associating temperature and moisture variables with mean disease data. Recently a new fundamental-empirical approach for estimating Fusarium index (incidence% x severity%/100) was developed using data of Pergamino and Marcos Juarez (32° 41′ S, 62°07′ W). In this study our objective was to validate both approaches at three more southern locations: La Dulce (38° 10′ S, 58° 00′ W), Miramar (38° 00′ S, 57° 33′ W) and Balcarce (37° 45′ S, 58° 18W), for the 2001 crop season. Examining partial and mean deviation values between observed and predicted incidence data, an underestimation especially at La Dulce was assessed. A clear improvement of incidence goodness of fit estimations was obtained decreasing the heat accumulation defining the length of the wheat critical period for infection. Employing this last critical period length for the fundamental-empirical approach led to satisfactory Fusarium index predictions. This study showed that both approaches developed at northern locations of the Pampas region can be portable and useful for predicting disease intensity at more southern locations, making only a few changes.Centro de Investigaciones en Fitopatologí

The impact of COVID-19 pandemic on pornography habits: a global analysis of Google Trends

As the COVID-19 spread globally, social distancing, self-isolation/quarantine, and national lockdowns have become crucial to control the pandemic. However, these measures may also lead to increases in social isolation, loneliness, and stress, which can alter the consumption of pornography habits. The aim of the study was thus to explore the interest pattern in pornography and coronavirus-themed pornography during the COVID-19 outbreak. Google Trends\uae was employed to determine the most popular porn websites (Porn, XNXX, PornHub, xVideos, and xHamster), and coronavirus-themed pornography worldwide and in six nations with different COVID-19 outbreak and self-isolation recommendations. We analyzed every search trend on Google\uae from January 9, 2020 to May 25, 2020 using \u201cjoint point regression analysis\u201d. Comparisons of week relative search volume (WRSV) and temporal patterns were analyzed to assess the change of interest in search terms during nations lockdowns. Paired t-test was used to compare WRSV values among the porn websites during the national lockdowns and the equivalent timespan of the weeks in the previous 4 years. The research trend of almost every keyword increased with significant inflection points for those nations with a straight \u201cstay at home orders\u201d (China, Italy, Spain, and France). \u201cPornHub\u201d and \u201cPorn\u201d showed the highest increase of interest worldwide with an average weekend percentage change (AWPC) of 4.9 and 3.8, respectively. The mean WRSV for keywords in USA and Sweden did not show a similar increase as the other nations. The WRSV percentage change with the historical data had a peak during the straight nations\u2019 lockdowns (p < 0.01). All the nations had a significant increase in WRSV coronavirus-themed pornography for each keyword (p < 0.01) with an AWPC, ranging worldwide between 18.5 and 61.8 (p < 0.01), after the beginning of self-quarantine. As strengths this study uses a big data technology to collect worldwide trend of interest, however, data are anonymous and do not allow analysis of subpopulation groups. In conclusion, we demonstrated an increased interest in pornography and coronavirus-themed pornography after the outbreak of COVID-19 in nations with a straight \u201cstay at home orders\u201d