抗生素和重金属是两种重要的环境污染物和耐药性选择压力源,但低含量水平下其对环境微生物种群耐药性水平的影响尚不明确.本文全面检索了截至2020年1月1日发表在Web of Science数据库中同时监测了抗生素抗性基因(ARGs)丰度、抗生素含量...抗生素和重金属是两种重要的环境污染物和耐药性选择压力源,但低含量水平下其对环境微生物种群耐药性水平的影响尚不明确.本文全面检索了截至2020年1月1日发表在Web of Science数据库中同时监测了抗生素抗性基因(ARGs)丰度、抗生素含量或重金属含量的研究文献,提取相关数据,利用统计回归方法调查环境介质中3个参数的相关关系.结果表明,除废水外,地表水、沉积物和土壤等环境介质中,即使在非常低的抗生素含量水平下,抗生素选择压力也会对ARGs丰度的增加产生显著的统计效应(P<0.05).不同类别抗生素对耐药基因表现出不同程度的选择和富集作用.重金属含量以及抗生素含量和重金属含量的交互作用对ARGs的传播也具有显著影响(P<0.05).水相和固相环境样本的多变量统计回归模型的最终R2分别为0.482和0.707,比单变量回归的R2更高,能更好地解释ARGs丰度的差异,但环境中还存在其他可能影响ARGs丰度的因素.本文的研究结果可为环境中抗生素耐药性风险评估及传播控制提供支撑.展开更多
With the ever-increasing diversification of people’s interests and preferences,artwork has become one of the most popular commodities or investment goods in E-commerce,and it increasingly attracts the attention of th...With the ever-increasing diversification of people’s interests and preferences,artwork has become one of the most popular commodities or investment goods in E-commerce,and it increasingly attracts the attention of the public.Currently,many real-world or virtual artworks can be found in E-commerce,and finding a means to recommend them to appropriate users has become a significant task to alleviate the heavy burden on artwork selection decisions by users.Existing research mainly studies the problem of single-artwork recommendation while neglecting the more practical but more complex composite recommendation of artworks in E-commerce,which considerably influences the quality of experience of potential users,especially when they need to select a set of artworks instead of a single artwork.Inspired by this limitation,we put forward a novel composite recommendation approach to artworks by a user keyword-driven correlation graph search named ART_(com-rec).Through ART_(com-rec),the recommender system can output a set of artworks(e.g.,an artwork composite solution)in E-commerce by considering the keywords typed by a user to indicate his or her personalized preferences.Finally,we validate the feasibility of the ART_(com-rec) approach by a set of simulated experiments on a real-world PW dataset.展开更多
The paper presents a novel benefit based query processing strategy for efficient query routing. Based on DHT as the overlay network, it first applies Nash equilibrium to construct the optimal peer group based on the c...The paper presents a novel benefit based query processing strategy for efficient query routing. Based on DHT as the overlay network, it first applies Nash equilibrium to construct the optimal peer group based on the correlations of keywords and coverage and overlap of the peers to decrease the time cost, and then presents a two-layered architecture for query processing that utilizes Bloom filter as compact representation to reduce the bandwidth consumption. Extensive experiments conducted on a real world dataset have demonstrated that our approach obviously decreases the processing time, while improves the precision and recall as well.展开更多
In this paper, a template matching and location method, which has been rapidly adopted in microseismic research in recent years, is applied to laboratory acoustic emission(AE) monitoring. First, we used traditional me...In this paper, a template matching and location method, which has been rapidly adopted in microseismic research in recent years, is applied to laboratory acoustic emission(AE) monitoring. First, we used traditional methods to detect P-wave first motions and locate AE hypocenters in three dimensions. In addition, we selected events located with sufficient accuracy(normally corresponding AE events of relatively larger energy, showing clear P-wave first motion and a higher signal-to-noise ratio in most channels) as template events. Then, the template events were used to scan and match other poorly located events in triggered event records or weak events in continuous records. Through crosscorrelation of the multi-channel waveforms between the template and the event to be detected, the weak signal was detected and located using a grid-searching algorithm(with the grid centered at the template hypocenter). In order to examine the performance of the approach, we calibrated the proposed method using experimental data of different rocks and different types of experiments. The results show that the proposed method can significantly improve the detection capability and location accuracy, and can be applied to various laboratory and in situ experiments, which use multi-channel AE monitoring with waveforms recorded in either triggering or continuous mode.展开更多
文摘抗生素和重金属是两种重要的环境污染物和耐药性选择压力源,但低含量水平下其对环境微生物种群耐药性水平的影响尚不明确.本文全面检索了截至2020年1月1日发表在Web of Science数据库中同时监测了抗生素抗性基因(ARGs)丰度、抗生素含量或重金属含量的研究文献,提取相关数据,利用统计回归方法调查环境介质中3个参数的相关关系.结果表明,除废水外,地表水、沉积物和土壤等环境介质中,即使在非常低的抗生素含量水平下,抗生素选择压力也会对ARGs丰度的增加产生显著的统计效应(P<0.05).不同类别抗生素对耐药基因表现出不同程度的选择和富集作用.重金属含量以及抗生素含量和重金属含量的交互作用对ARGs的传播也具有显著影响(P<0.05).水相和固相环境样本的多变量统计回归模型的最终R2分别为0.482和0.707,比单变量回归的R2更高,能更好地解释ARGs丰度的差异,但环境中还存在其他可能影响ARGs丰度的因素.本文的研究结果可为环境中抗生素耐药性风险评估及传播控制提供支撑.
文摘With the ever-increasing diversification of people’s interests and preferences,artwork has become one of the most popular commodities or investment goods in E-commerce,and it increasingly attracts the attention of the public.Currently,many real-world or virtual artworks can be found in E-commerce,and finding a means to recommend them to appropriate users has become a significant task to alleviate the heavy burden on artwork selection decisions by users.Existing research mainly studies the problem of single-artwork recommendation while neglecting the more practical but more complex composite recommendation of artworks in E-commerce,which considerably influences the quality of experience of potential users,especially when they need to select a set of artworks instead of a single artwork.Inspired by this limitation,we put forward a novel composite recommendation approach to artworks by a user keyword-driven correlation graph search named ART_(com-rec).Through ART_(com-rec),the recommender system can output a set of artworks(e.g.,an artwork composite solution)in E-commerce by considering the keywords typed by a user to indicate his or her personalized preferences.Finally,we validate the feasibility of the ART_(com-rec) approach by a set of simulated experiments on a real-world PW dataset.
基金Supported by the National Natural Science Foundation of China (60673139, 60473073, 60573090)
文摘The paper presents a novel benefit based query processing strategy for efficient query routing. Based on DHT as the overlay network, it first applies Nash equilibrium to construct the optimal peer group based on the correlations of keywords and coverage and overlap of the peers to decrease the time cost, and then presents a two-layered architecture for query processing that utilizes Bloom filter as compact representation to reduce the bandwidth consumption. Extensive experiments conducted on a real world dataset have demonstrated that our approach obviously decreases the processing time, while improves the precision and recall as well.
基金funding support from Grant-in-Aid for Scientific Research(Grant No.19H00722)by Japan Society for the Promotion of Science(JSPS)。
文摘In this paper, a template matching and location method, which has been rapidly adopted in microseismic research in recent years, is applied to laboratory acoustic emission(AE) monitoring. First, we used traditional methods to detect P-wave first motions and locate AE hypocenters in three dimensions. In addition, we selected events located with sufficient accuracy(normally corresponding AE events of relatively larger energy, showing clear P-wave first motion and a higher signal-to-noise ratio in most channels) as template events. Then, the template events were used to scan and match other poorly located events in triggered event records or weak events in continuous records. Through crosscorrelation of the multi-channel waveforms between the template and the event to be detected, the weak signal was detected and located using a grid-searching algorithm(with the grid centered at the template hypocenter). In order to examine the performance of the approach, we calibrated the proposed method using experimental data of different rocks and different types of experiments. The results show that the proposed method can significantly improve the detection capability and location accuracy, and can be applied to various laboratory and in situ experiments, which use multi-channel AE monitoring with waveforms recorded in either triggering or continuous mode.
