Oviposition Suitability of Drosophila Suzukii (Diptera: Drosophilidae) for Nectarine Varieties and Its Correlation with the Physiological Indexes.

The nectarine is an important fruit, which is attacked by Drosophila suzukii in Europe and the United States but there are no reports of it attacking nectarines in China. Here, we determined the oviposition preference of D. suzukii six on intact and sliced nectarine varieties in China and how physical and physiological indexes of the fruit correlate with these preferences. D. suzukii were allowed to oviposit on two early-, two middle- and two late-maturing varieties of nectarine-Shuguang and Chunguang, Fengguang and Zhong you 4, Zhong you 7 and Zhong you 8, respectively and the number of larvae also followed the order. The firmness, soluble solids content and the nutritional components of the amino acid, protein, soluble sugar and pectin contents of each variety were measured. D. suzukii preferred the early Shuguang variety, followed by the early Chunguang variety and then the middle Zhong you 4 and Fengguang varieties. Taken together, results show that D. suzukii shows preferences for earlier rather than later varieties of nectarines in China and that these preferences are related to the fruit's physical and physiological traits. Results suggest that mixed cultivation of early-, middle- and late-maturing nectarine varieties should be avoided in order to prevent fly dispersal and infestation by D. suzukii.

[Simulation of the Spatio-temporally Resolved PM2.5 Aerosol Mass Concentration over the Inland Plain of the Beijing-Tianjin-Hebei Region].

In recent years, haze pollution in China is becoming increasingly serious, especially in the Beijing-Tianjin-Hebei region. In order to identify the temporal and spatial distributional characteristics of PM2.5 aerosol mass concentration in the region, this study selected the inland plain of the Beijing-Tianjin-Hebei region as the research area, and used MODIS AOD as the main predictor in a mixed effects model to establish the daily relationship of AOD-PM2.5 in the study area, from 2013 to 2014. The model was validated by a ten-fold cross validation method. The results showed that the correlation between AOD-PM2.5 can be improved by daily calibration of the mixed effects model (R2=0.78); the cross-validated R2 was 0.70, and RMSE and RPE were 20.80 µg·m-3 and 28.76%, respectively. Considering the importance of unbiased PM2.5 predictions, the correction factors calculated from the surface PM2.5 measurements were applied to correct the biases in the predicted annual average PM2.5 concentrations introduced by non-stochastic missing AOD measurements. The results showed that the annual average concentration of PM2.5 in the study area was higher than 75 µg·m-3, and the spatial distribution of PM2.5 concentration was higher in the southern and western regions, and lower in the northern and eastern regions. These results suggest that the mixed effects model can be used to monitor ground PM2.5, and also provide a scientific basis for the control of atmospheric particulate pollution in the region.

Changing reaction pathways of the dimerization of 2-formylcinnamates by N-heterocyclic carbene/Lewis acid cooperative catalysis: an unusual cleavage of the carbon-carbon bond.

Catalyzed by a triazole carbene, the dimerization of 2-formylcinnamates underwent benzoin condensation followed by intramolecular oxa-Michael addition to afford isochromeno[4,3-c]isochromene products. Under the catalysis of a combination of triazole carbene and Ti(OPr-i)4 catalysts, the dimerization reaction of 2-formylcinnamates proceeded through a completely different route to furnish the formation of isochromenone derivatives with the elimination of an acetate moiety.