302 research outputs found
Aid for Trade and the Quality of Exports
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.This paper studies how aid for trade (AfT) affects the quality of recipient countries’ exports. It shows that the quality effect is most discernible for AfT for assistance in trade policy: a 50% increase in the value of AfT received in this category is associated with a 0.5%-1% increase in the quality of exports to the donor and other OECD countries. On average, the actual AfT received for assistance in trade policy leads to a 2% upgrade of the recipient country in the quality ladder of all developing countries. Around half of this quality effect is driven by the quality improvement of continued products in continued markets (intensive margin), and the other half by the quality upgrading of new products in continued markets and existing products in new markets (extensive margin)
The mediating effect of body mass index on the relationship between cigarette smoking and atopic sensitization in Chinese adults
Background: It is unclear whether the relationship between cigarette smoking and atopy is mediated by body fat mass, such as the Body Mass Index (BMI). We assessed the mediating role of BMI on the relationship between smoking and atopy in Chinese adults. Methods: A hospital-based case-control study of 786 atopic cases and 2771 controls was conducted in adults aged 18 years or older from March 2010 to September 2014 in Harbin, China. Mediation models were used to estimate the indirect effects of smoking on atopic sensitization through BMI. Results: Compared to non-smokers, light smokers and moderate smokers had a lower risk of inhalant allergen sensitization. The indirect effect of smoking and sensitization to aeroallergens were only observed in light smokers (point estimate, -0.026; 95% CI, -0.062 to -0.004). The mediating roles of BMI on the relationships between smoking and other types of allergic sensitization were not statistically significant. Conclusion: BMI appeared to partially mediate the effect of light smoking on sensitization to aeroallergens. However, considering the other harmful health effects of cigarette smoking, the effective method to lower the incidence of atopy would be to decrease body fat mass by physical exercise and employing other more healthy ways of living rather than smoking
Engineering Escherichia coli for succinate production from hemicellulose via consolidated bioprocessing
<p>Abstract</p> <p>Background</p> <p>The recalcitrant nature of hemicellulosic materials and the high cost in depolymerization are the primary obstacles preventing the use of xylan as feedstock for fuel and chemical production. Consolidated bioprocessing, incorporating enzyme-generating, biomass-degrading and bioproduct-producing capabilities into a single microorganism, could potentially avoid the cost of the dedicated enzyme generation in the process of xylan utilization. In this study, we engineered <it>Escherichia coli </it>strains capable of exporting three hemicellulases to the broth for the succinate production directly from beechwood xylan.</p> <p>Results</p> <p>Xylanases were extracellular environment-directed by fusing with OsmY. Subsequently, twelve variant OsmY fused endoxylanase-xylosidase combinations were characterized and tested. The combination of XynC-A from <it>Fibrobacter succinogenes </it>S85 and XyloA from <it>Fusarium graminearum </it>which appeared to have optimal enzymatic properties was identified as the best choice for xylan hydrolysis (0.18 ± 0.01 g/l protein in the broth with endoxylanase activity of 12.14 ± 0.34 U/mg protein and xylosidase activity of 92 ± 3 mU/mg protein at 8 h after induction). Further improvements of hemicellulases secretion were investigated by <it>lpp </it>deletion, <it>dsbA </it>overexpression and expression level optimization. With co-expression of α-arabinofuranosidase, the engineered <it>E. coli </it>could hydrolyze beechwood xylan to pentose monosaccharides. The hemicellulolytic capacity was further integrated with a succinate-producing strain to demonstrate the production of succinate directly from xylan without externally supplied hydrolases and any other organic nutrient. The resulting <it>E. coli </it>Z6373 was able to produce 0.37 g/g succinate from xylan anaerobically equivalent to 76% of that from xylan acid hydrolysates.</p> <p>Conclusions</p> <p>This report represents a promising step towards the goal of hemicellulosic chemical production. This engineered <it>E. coli </it>expressing and secreting three hemicellulases demonstrated a considerable succinate production on the released monosaccharides from xylan. The ability to use lower-cost crude feedstock will make biological succinate production more economically attractive.</p
Abnormal Event Detection Based on Deep Autoencoder Fusing Optical Flow
International audienceAs an important research topic in computer vision, abnormal detection has gained more and more attention. In order to detect abnormal events effectively, we propose a novel method using optical flow and deep autoencoder. In our model, optical flow of the original video sequence is calculated and visualized as optical flow image, which is then fed into a deep autoencoder. Then the deep autoencoder extract features from the training samples which are compressed to low dimension vectors. Finally, the normal and abnormal samples gather separately in the coordinate axis. In the evaluation, we show that our approach outperforms the existing methods in different scenes, in terms of accuracy
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