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Rice (Oryza sativa L.) production faces a worldwide challenge of severe water scarcity. The ground cover rice production system (GCRPS) is one alternative to the paddy system, using plastic‐film covering and less irrigation water. As contradictory yield performances occurred throughout different regions, a general evaluation of GCRPS was seldom reported. Therefore, a 7‐yr experiment was conducted in a mountainous area of the Hubei Province from 2003 to 2009. the paddy system and GCRPS were compared with 0 and 150 kg N ha−1, where crop growth, yield, plant N uptake, and soil C and N were measured to evaluate the adaptability, stability, and sustainability of GCRPS. Under GCRPS, grain yield was significantly higher than under the paddy system during the 7‐yr period. Additionally, the interannual difference in grain yield under GCRPS was significantly lower than under the paddy system. Furthermore, vegetative growth of GCRPS plants was improved with a sufficient N supply, while reproductive growth was limited with N reduction, which led to low number of spikelets and filled grains. Soil organic C and total N (0–20‐cm soil depth) were both significantly lower under GCRPS than paddy cultivation, while N fertilization slightly reversed organic C and N reductions. Hence, GCRPS is highly adoptable and stable in typical paddy areas where water scarcity and low temperature occur and high clay and organic matter contents prevail. Further research is needed to evaluate GCRPS in other related locations and to assess new techniques for achieving continuous soil N supply to the reproductive stage and increasing sustainability under GCRPS.

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Most recommendation systems face challenges from products that change with time, such as popular or seasonal products, since traditional market basket analysis or collaborative filtering analysis are unable to recommend new products to customers due to the fact that the products are not yet purchased by customers. Although the recommendation systems can find customer groups that have similar interests as target customers, brand new products often lack ratings and comments. Similarly, products that are less often purchased, such as furniture and home appliances, have fewer records of ratings; therefore, the chances of being recommended are often lower. This research attempts to analyze customers' purchasing behaviors based on product features from transaction records and product feature databases. Customers' preferences toward particular features of products are analyzed and then rules of customer interest profiles are thus drawn in order to recommend customers products that have potential attraction with customers. The advantage of this research is its ability of recommending to customers brand new products or rarely purchased products as long as they fit customer interest profiles; a deduction which traditional market basket analysis and collaborative filtering methods are unable to do. This research uses a two-stage clustering technique to find customers that have similar interests as target customers and recommend products to fit customers' potential requirements. Customers' interest profiles can explain recommendation results and the interests on particular features of products can be referenced for product development, while a oneto-one marketing strategy can improve profitability for companies. q

Alkylimidazolium/alkylpyridinium octamolybdates can be used as self-separating catalysts in acetonitrile-mediated olefin epoxidations using hydrogen peroxide as oxidant.

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This study investigated the risk factors and early predictors for heterotopic pregnancy (HP) after in vitro fertilization and embryo transfer (IVF-ET). From January 2008 to January 2013, 41 cases of HP and 72 cases of intrauterine twin pregnancy after IVF-ET were recruited and retrospectively analyzed. Compared with intrauterine twin pregnancy group, the HP group had a lower basal luteinizing hormone (LH) level (P = 0.005) and more cases had a history of hydrosalpinx (P = 0.008). After 14 days of IVF-ET, the serum β-HCG (β-human chorionic gonadotropin), E2 (Estradiol) and P (Progesterone) levels were lower in HP group (P<0.001, respectively). Moreover, vaginal bleeding and abdominal pain were the significant features of HP before diagnosis (P<0.001, respectively). Further by logistic regression, serum β-hCG, P levels on the 14th day after ET, and vaginal bleeding were identified as the independent factors of HP. These results indicate that when two or more embryos transferred in IVF procedure, β-hCG, P levels on the 14th day after ET, and vaginal bleeding could be taken as predictors for HP.

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